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1.
  • Marichelvam, M.K., et al. (author)
  • Investigation on mechanical properties of novel natural fiber-epoxy resin hybrid composites for engineering structural applications
  • 2023
  • In: Case Studies in Construction Materials. - : Elsevier. - 2214-5095. ; 19
  • Journal article (peer-reviewed)abstract
    • Polymers and fibers are the main components of cementitious composite materials to reinforce concrete. The synthetic fibers used in concrete composites typically weigh and also, and they are easily subjected to thermal degradation. To tackle the above issues, researchers developed various natural fiber-based composites. In the paper, the mechanical characteristics of hybrid composites were examined. The hybrid composites were developed using Madar, Gongura, and Hibiscus cannabinus fibers. The polyester resin was the matrix. The fibers were treated chemically using a 5% sodium hydroxide (NaOH) solution. The fibers were then carefully cleaned with distilled water twice and baked for 70 min at 60 °C. For the evaluation of the tensile, flexural, and impact properties of the hybrid composites, specimens were made in accordance with ASTM standards. The treated composite sample (S3) specimen exhibits a tensile strength (TS) of approximately 34.720 N/mm2, flexural strength (FS) of 77.957 MPa, and flexural modulus (FM) of 1548.588 GPa. The average water absorption of the sample is only 2.45%. The hardness and impact strength (IS) of the samples are also superior to those of several other composites studied in the literature. Hence, the proposed hybrid composites could be a potential material for reinforcing the concrete composites to provide a higher service rate and greater durability to the structures.
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2.
  • Kumar, A. Naresh, et al. (author)
  • Upgrading the value of anaerobic fermentation via renewable chemicals production : A sustainable integration for circular bioeconomy
  • 2022
  • In: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 806, part 1
  • Research review (peer-reviewed)abstract
    • The single bioprocess approach has certain limitations in terms of process efficiency, product synthesis, and effective resource utilization. Integrated or combined bioprocessing maximizes resource recovery and creates a novel platform to establish sustainable biorefineries. Anaerobic fermentation (AF) is a well-established process for the transformation of organic waste into biogas; conversely, biogas CO2 separation is a challenging and cost-effective process. Biological fixation of CO2 for succinic acid (SA) mitigates CO2 separation issues and produces commercially important renewable chemicals. Additionally, utilizing digestate rich in volatile fatty acid (VFA) to produce medium-chain fatty acids (MCFAs) creates a novel integrated platform by utilizing residual organic metabolites. The present review encapsulates the advantages and limitations of AF along with biogas CO2 fixation for SA and digestate rich in VFA utilization for MCFA in a closed-loop approach. Biomethane and biohydrogen process CO2 utilization for SA production is cohesively deliberated along with the role of biohydrogen as an alternative reducing agent to augment SA yields. Similarly, MCFA production using VFA as a substrate and function of electron donors namely ethanol, lactate, and hydrogen are comprehensively discussed. A road map to establish the fermentative biorefinery approach in the framework of AF integrated sustainable bioprocess development is deliberated along with limitations and factors influencing for techno-economic analysis. The discussed integrated approach significantly contributes to promote the circular bioeconomy by establishing carbon-neutral processes in accord with sustainable development goals.
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3.
  • Kumar Dey, Tushar, et al. (author)
  • Analyses of Extended-Spectrum-β-Lactamase, Metallo-β-Lactamase, and AmpC-β-Lactamase Producing Enterobacteriaceae from the Dairy Value Chain in India
  • 2023
  • In: Antibiotics. - : MDPI. - 2079-6382. ; 12:9
  • Journal article (peer-reviewed)abstract
    • The consumption of milk contaminated with antibiotic-resistant bacteria poses a significant health threat to humans. This study aimed to investigate the prevalence of Enterobacteriaceae producing β-lactamases (ESBL, MBL, and AmpC) in cow and buffalo milk samples from two Indian states, Haryana and Assam. A total of 401 milk samples were collected from dairy farmers and vendors in the specified districts. Microbiological assays, antibiotic susceptibility testing, and PCR-based genotyping were employed to analyze 421 Gram-negative bacterial isolates. The overall prevalence of β-lactamase genes was 10% (confidence interval (CI) (7–13)), with higher rates in Haryana (13%, CI (9–19)) compared to Assam (7%, CI (4–11)). The identified β-lactamase genes in isolates were blaCMY, blaMOX, blaFOX, blaEBC, and blaDHA, associated with AmpC production. Additionally, blaCTX-M1, blaSHV, and blaTEM were detected as ESBL producers, while blaVIM, blaIMP, blaSPM, blaSIM, and blaGIM were identified as MBL producers. Notably, Shigella spp. were the dominant β-lactamase producers among identified Enterobacteriaceae. This study highlights the presence of various prevalent β-lactamase genes in milk isolates, indicating the potential risk of antimicrobial-resistant bacteria in dairy products. The presence of β-lactam resistance raises concern as this could restrict antibiotic options for treatment. The discordance between genotypic and phenotypic methods emphasizes the necessity for comprehensive approaches that integrate both techniques to accurately assess antibiotic resistance. Urgent collaborative action incorporating rational and regulated use of antibiotics across the dairy value chain is required to address the global challenge of β-lactam resistance.
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4.
  • Kumar Dey, Tushar, et al. (author)
  • Molecular Characterization of Methicillin-Resistant Staphylococci from the Dairy Value Chain in Two Indian States
  • 2023
  • In: Pathogens. - : MDPI. - 2076-0817. ; 12:2
  • Journal article (peer-reviewed)abstract
    • Bovine milk and milk products may contain pathogens, antimicrobial resistant bacteria, and antibiotic residues that could harm consumers. We analyzed 282 gram-positive isolates from milk samples from dairy farmers and vendors in Haryana and Assam, India, to assess the prevalence of methicillin-resistant staphylococci using microbiological tests, antibiotic susceptibility testing, and genotyping by PCR. The prevalence of genotypic methicillin resistance in isolates from raw milk samples was 5% [95% confidence interval, CI (3-8)], with 7% [CI (3-10)] in Haryana, in contrast to 2% [CI (0.2-6)] in Assam. The prevalence was the same in isolates from milk samples collected from farmers [5% (n = 6), CI (2-11)] and vendors [5% (n = 7), CI (2-10)]. Methicillin resistance was also observed in 15% of the isolates from pasteurized milk [(n = 3), CI (3-38)]. Two staphylococci harboring a novel mecC gene were identified for the first time in Indian dairy products. The only SCCmec type identified was Type V. The staphylococci with the mecA (n = 11) gene in raw milk were commonly resistant to oxacillin [92%, CI (59-100)] and cefoxitin [74%, CI (39-94)], while the isolates with mecC (n = 2) were resistant to oxacillin (100%) only. All the staphylococci with the mecA (n = 3) gene in pasteurized milk were resistant to both oxacillin and cefoxitin. Our results provided evidence that methicillin-resistant staphylococci occur in dairy products in India with potential public health implications. The state with more intensive dairy systems (Haryana) had higher levels of methicillin-resistant bacteria in milk.
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5.
  • Kumar, Naresh, et al. (author)
  • Understanding Antibiotic Usage on Small-Scale Dairy Farms in the Indian States of Assam and Haryana Using a Mixed-Methods Approach—Outcomes and Challenges
  • 2021
  • In: Antibiotics. - : MDPI. - 2079-6382. ; 10:9, s. 1124-1124
  • Journal article (peer-reviewed)abstract
    • The use and misuse of antibiotics in both humans and animals contributes to the global emergence of antimicrobial resistant (AMR) bacteria, a threat to public health and infection control. Currently, India is the world’s leading milk producer but antibiotic usage within the dairy sector is poorly regulated. Little data exists reflecting how antibiotics are used on dairy farms, especially on small-scale dairy farms in India. To address this lack of data, a study was carried out on 491 small-scale dairy farms in two Indian states, Assam and Haryana, using a mixed method approach where farmers were interviewed, farms inspected for the presence of antibiotics and milk samples taken to determine antibiotic usage. Usage of antibiotics on farms appeared low only 10% (95% CI 8–13%) of farmers surveyed confirmed using antibiotics in their dairy herds during the last 12 months. Of the farms surveyed, only 8% (6–11%) had milk samples positive for antibiotic residues, namely from the novobiocin, macrolides, and sulphonamide classes of antibiotics. Of the farmers surveyed, only 2% (0.8–3%) had heard of the term “withdrawal period” and 53% (40–65%) failed to describe the term “antibiotic”. While this study clearly highlights a lack of understanding of antibiotics among small-scale dairy farmers, a potential factor in the emergence of AMR bacteria, it also shows that antibiotic usage on these farms is low and that the possible role these farmers play in AMR emergence may be overestimated.
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6.
  • Kumar Wagri, Naresh, et al. (author)
  • Investigation on the performance of coated carbide tool during dry turning of AISI 4340 alloy steel
  • 2023
  • In: Materials. - : MDPI. - 1996-1944. ; 16:2
  • Journal article (peer-reviewed)abstract
    • The machinability of materials is highly affected by their hardness, and it affects power consumption, cutting tool life as well as surface quality while machining the component. This work deals with machining of annealed AISI 4340 alloy steel using a coated carbide tool under a dry environment. The microhardness of annealed and non-annealed workpieces was compared and a significant reduction was found in the microhardness of annealed samples. Microstructure examination of the annealed sample revealed the formation of coarse pearlite which indicated a reduction of hardness and improved ductility. A commercially CVD multilayer (TiN/TiCN/Al2O3/ZrCN) coated cemented carbide cutting tool was employed for turning quenched and tempered structural AISI 4340 alloy steel by varying machining speed, rate of feed, and depth of cut to evaluate the surface quality, machining forces, flank wear, and chip morphology. According to the findings of experiments, the feed rate possesses a high impact on surface finish, followed by cutting speed. The prominent shape of the serrated saw tooth chip was noticed at a higher cutting speed. Machined surface finish and cutting forces during turning is a function of the wear profile of the coated carbide insert. This study proves that annealing is a low-cost and economical process to enhance the machinability of alloy steel.
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7.
  • Maurya, Naresh Chandra, et al. (author)
  • Exciton many-body interactions and charge transfer in CsPbBr3/graphene derivatives
  • 2023
  • In: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 108:15
  • Journal article (peer-reviewed)abstract
    • Charge separation and many-body interactions at the interface of the light-absorbing semiconductor and contact layer are of crucial importance to the photophysical properties and optoelectronic device performance. Here, we report the exciton many-body interactions and charge transfer dynamics at the interface of metal halide perovskite nanocrystals and graphene derivatives [graphene oxide (GO) and reduced GO (RGO)] using ultrafast transient absorption (TA) and time-resolved photoluminescence (PL) measurements. At the early timescales, the TA spectra of CsPbBr3/GO and CsPbBr3/RGO show an asymmetric derivative feature originating from the exciton many-body interactions. The band gap renormalization and binding energies of exciton and biexciton of CsPbBr3 nanocrystals are significantly reduced in CsPbBr3/GO(RGO) due to the charge transfer and change in the dielectric environment, respectively. More specifically, the exciton (biexciton) binding energy of CsPbBr3 nanocrystals, originally 38 +/- 2 (34 +/- 1) meV, decreases to 27 +/- 1 (22 +/- 1) meV in CsPbBr3/RGO and 17 +/- 1 (15 +/- 1) meV in CsPbBr3/GO. Furthermore, we observe a reduction in the Auger recombination rate and exciton PL quenching in CsPbBr3/GO and CsPbBr3/RGO, corroborating the charge transfer mechanism. Our systematic studies successfully describe photoexcited charge transfer from CsPbBr3 nanocrystals to GO (RGO) in 7.0 +/- 0.4 (4.2 +/- 0.1) ps, which is one order of magnitude faster than the charge transfer for other acceptor materials such as metal oxide, fullerene, anthraquinone, 1-aminopyrene, and phenothiazine. Our results offer insights and guidance for perovskite-based high-performance optoelectronic devices.
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8.
  • Sharma, Garima, et al. (author)
  • A qualitative study on antibiotic use and animal health management in smallholder dairy farms of four regions of India
  • 2020
  • In: Infection Ecology & Epidemiology. - : Taylor & Francis. - 2000-8686. ; 10:1
  • Journal article (peer-reviewed)abstract
    • BackgroundAntimicrobial resistance (AMR) is a major global public health issue. In India, access to medicines is poorly regulated and therefore antibiotics in dairy cattle are commonly used by farmers without consulting with veterinarians. This study was conducted to understand practices and knowledge related to antibiotic use and AMR among dairy farmers and veterinary professionals in selected urban and peri-urban areas of India.MethodsA total of 28 focus group discussions with farmers and 53 interviews with veterinary professionals were carried out.ResultsMastitiswas identified as the main animal health challenge. Antibiotic consultation behavior of farmers depended on the availability of veterinarians. Except in Bangalore, farmers were found to often treat animals on their own. They were found unaware of the concept of AMR, but knew the importance of vaccination. Veterinarians included in the study had a good understanding of antibiotics, AMR, and zoonotic diseases.ConclusionThe knowledge level and practices observed in the study related to the use/abuse of antibiotics can potentially increase the risk of development of AMR and its transfer in the community. Our findings can help support AMR – mitigation efforts in the country, including the design of better policies on antibiotic use in dairy.
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9.
  • Sharma, Garima, et al. (author)
  • Comparing the Effectiveness of Different Approaches to Raise Awareness About Antimicrobial Resistance in Farmers and Veterinarians of India
  • 2022
  • In: Frontiers In Public Health. - : Frontiers Media S.A.. - 2296-2565. ; 10
  • Journal article (peer-reviewed)abstract
    • BackgroundAntimicrobial resistance (AMR) is a global public health threat. The indiscriminate use of antibiotics in the animal health sector contributes to increasing rates of AMR and studies involving dairy farmers in India have found knowledge levels regarding antibiotics and AMR to be very low. The purpose of this study was to assess different methods to raise awareness and knowledge about AMR and antibiotic use among dairy farmers, paravets (veterinary assistants), and veterinarians. Materials and MethodsThe study was conducted in September-December of 2018 in some parts of Haryana, Assam, Karnataka, and West Bengal. It had two parts: an intervention meeting (September-October 2018) which consisted of focus group discussions (FGD) with farmers, key informant interviews (KII) with veterinary professionals along with distribution of information packages, and then a follow-up survey (November-December 2018). The villages were randomly allocated to either one of the four intervention approaches (1-FGD/KII and information package on AMR; 2-FGD/KI and information on animal health; 3- FGD/KII and information package on animal health plus information on AMR; or 4- only the FGD/KII). A follow-up survey was done to assess the effect of interventions. ResultsIn total, 274 dairy farmers and 51 veterinary professionals (21 veterinarians and 30 paravets) participated in the follow-up survey. Many of the farmers and veterinary professionals who participated in the follow-up survey had been part of the intervention meetings. The average knowledge score of farmers was 7.8. It was found that the knowledge score was higher amongst farmers who had participated in the intervention meetings (p < 0.05), had received intervention approach 2 (p = 0.03) or approach 3 (p = 0.01), and amongst female farmers (p = 0.03) compared to male. The veterinary professionals had good knowledge but lacked interest in training the farmers about antimicrobial resistance. ConclusionOur research demonstrated that a higher percentage of farmers and veterinary professionals who attended the intervention meeting had improved knowledge. Dairy farmers should be regularly educated on antibiotic usage and how to avoid misusing them. Also, veterinary experts should be provided with tools and strategies to educate farmers on the use of antimicrobials.
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11.
  • Cachafeiro, Miguel A. Torre, et al. (author)
  • Pulsed operation of perovskite LEDs: a study on the role of mobile ions
  • 2024
  • In: NATIONAL SCIENCE REVIEW. - : OXFORD UNIV PRESS. - 2095-5138.
  • Journal article (peer-reviewed)abstract
    • Metal halide perovskite light-emitting diodes (PeLEDs) are a promising technology for energy-efficient and cost-effective lighting and displays, thanks to their tunable color emission, high brightness, color purity and low-temperature fabrication. However, the mixed ionic-electronic conductivity of perovskite materials presents unique challenges, as ionic defects can redistribute under operation, affecting the energy landscape and charge recombination mechanisms. Our drift-diffusion simulations establish a connection between the transient electroluminescence (TrEL) signals of PeLEDs under pulsed operation and the influence of mobile ions. We find that the TrEL plateau value's dependence on the duty cycle and end-of-pulse overshoot can be explained by the time-varying distribution of ionic defects. The inclusion of mobile ions is crucial to understand the TrEL response. Moreover, the simulations highlight injection barriers at the perovskite/charge-transport layer interfaces, such as is the case for the hole transport layer in our example, as a significant source of non-radiative charge recombination. These findings contribute to the understanding of transient ionic processes in perovskite-based devices. This study explores ionic redistribution in perovskite LEDs during pulsed operation, using drift-diffusion simulations to analyze the impact of mobile ionic defects on light emission and providing insights into the functionality of these promising devices.
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12.
  • Das, Theerthankar, et al. (author)
  • Ascorbic acid modulates the structure of the Pseudomonas aeruginosa virulence factor pyocyanin and ascorbic acid-furanone-30 combination facilitate biofilm disruption
  • 2023
  • In: Frontiers in Microbiology. - 1664-302X. ; 14
  • Journal article (peer-reviewed)abstract
    • The production of pyocyanin by Pseudomonas aeruginosa increases its virulence, fitness and biofilm formation. Pyocyanin is also a redox molecule and we hypothesize that ascorbic acid being an antioxidant will interact with pyocyanin. The main objective of this study was to investigate the potential interaction of ascorbic acid with pyocyanin, and also to investigate the impact of ascorbic acid in combination with Furanone-30 on quorum sensing and biofilm formation of P. aeruginosa. When incubated with ascorbic acid, hyperchromic and hypsochromic shifts in pyocyanin absorbance peaks at 385 nm and 695 nm were observed. In the presence of dehydroascorbic acid and citric acid, these shifts were absent, indicating that the intrinsic antioxidant property of ascorbic acid was probably essential in binding to pyocyanin. NMR spectroscopy showed shifts in 1H NMR pyocyanin peaks between 8.2 to 5.8 ppm when incubated in the presence of ascorbic acid. Density Functional Theory (DFT) supported potential interactions between the -CH2OH or -OH moieties of ascorbic acid with the -C=O moiety of pyocyanin. The pyocyanin-ascorbic acid complex impaired pyocyanin binding to DNA. Ascorbic acid combined with furanone-30 elevated quorum-sensing inhibition in P. aeruginosa, which was directly associated with significantly reduced P. aeruginosa virulence, adhesion, aggregation and biofilm formation and enhanced antibiotic-mediated bacterial killing. This study demonstrated that the antioxidant ascorbic acid directly binds to pyocyanin, modulates its structure and results in disruption of biofilm formation and associated tolerance to antibiotics.
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13.
  • Day, Louise T., et al. (author)
  • "Every Newborn-BIRTH" protocol : observational study validating indicators for coverage and quality of maternal and newborn health care in Bangladesh, Nepal and Tanzania
  • 2019
  • In: Journal of Global Health. - : International Global Health Society. - 2047-2978 .- 2047-2986. ; 9:1
  • Journal article (peer-reviewed)abstract
    • Background: To achieve Sustainable Development Goals and Universal Health Coverage, programmatic data are essential. The Every Newborn Action Plan, agreed by all United Nations member states and >80 development partners, includes an ambitious Measurement Improvement Roadmap. Quality of care at birth is prioritised by both Every Newborn and Ending Preventable Maternal Mortality strategies, hence metrics need to advance from health service contact alone, to content of care. As facility births increase, monitoring using routine facility data in DHIS2 has potential, yet validation research has mainly focussed on maternal recall surveys. The Every Newborn - Birth Indicators Research Tracking in Hospitals (EN-BIRTH) study aims to validate selected newborn and maternal indicators for routine tracking of coverage and quality of facility-based care for use at district, national and global levels.Methods: EN-BIRTH is an observational study including >20000 facility births in three countries (Tanzania, Bangladesh and Nepal) to validate selected indicators. Direct clinical observation will be compared with facility register data and a pre-discharge maternal recall survey for indicators including: uterotonic administration, immediate newborn care, neonatal resuscitation and Kangaroo mother care. Indicators including neonatal infection management and antenatal corticosteroid administration, which cannot be easily observed, will be validated using inpatient records. Trained clinical observers in Labour/Delivery ward, Operation theatre, and Kangaroo mother care ward/areas will collect data using a tablet-based customised data capturing application. Sensitivity will be calculated for numerators of all indicators and specificity for those numerators with adequate information. Other objectives include comparison of denominator options (ie, true target population or surrogates) and quality of care analyses, especially regarding intervention timing. Barriers and enablers to routine recording and data usage will be assessed by data flow assessments, quantitative and qualitative analyses.Conclusions: To our knowledge, this is the first large, multi-country study validating facility-based routine data compared to direct observation for maternal and newborn care, designed to provide evidence to inform selection of a core list of indicators recommended for inclusion in national DHIS2. Availability and use of such data are fundamental to drive progress towards ending the annual 5.5 million preventable stillbirths, maternal and newborn deaths.
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14.
  • Day, Louise T, et al. (author)
  • "Every Newborn-BIRTH" protocol: observational study validating indicators for coverage and quality of maternal and newborn health care in Bangladesh, Nepal and Tanzania.
  • 2019
  • In: Journal of global health. - : International Global Health Society. - 2047-2986 .- 2047-2978. ; 9:1
  • Journal article (peer-reviewed)abstract
    • To achieve Sustainable Development Goals and Universal Health Coverage, programmatic data are essential. The Every Newborn Action Plan, agreed by all United Nations member states and >80 development partners, includes an ambitious Measurement Improvement Roadmap. Quality of care at birth is prioritised by both Every Newborn and Ending Preventable Maternal Mortality strategies, hence metrics need to advance from health service contact alone, to content of care. As facility births increase, monitoring using routine facility data in DHIS2 has potential, yet validation research has mainly focussed on maternal recall surveys. The Every Newborn - Birth Indicators Research Tracking in Hospitals (EN-BIRTH) study aims to validate selected newborn and maternal indicators for routine tracking of coverage and quality of facility-based care for use at district, national and global levels.EN-BIRTH is an observational study including >20 000 facility births in three countries (Tanzania, Bangladesh and Nepal) to validate selected indicators. Direct clinical observation will be compared with facility register data and a pre-discharge maternal recall survey for indicators including: uterotonic administration, immediate newborn care, neonatal resuscitation and Kangaroo mother care. Indicators including neonatal infection management and antenatal corticosteroid administration, which cannot be easily observed, will be validated using inpatient records. Trained clinical observers in Labour/Delivery ward, Operation theatre, and Kangaroo mother care ward/areas will collect data using a tablet-based customised data capturing application. Sensitivity will be calculated for numerators of all indicators and specificity for those numerators with adequate information. Other objectives include comparison of denominator options (ie, true target population or surrogates) and quality of care analyses, especially regarding intervention timing. Barriers and enablers to routine recording and data usage will be assessed by data flow assessments, quantitative and qualitative analyses.To our knowledge, this is the first large, multi-country study validating facility-based routine data compared to direct observation for maternal and newborn care, designed to provide evidence to inform selection of a core list of indicators recommended for inclusion in national DHIS2. Availability and use of such data are fundamental to drive progress towards ending the annual 5.5 million preventable stillbirths, maternal and newborn deaths.
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15.
  • De Adhikari, Amrita, et al. (author)
  • Polyaniline-Stabilized Intertwined Network-like Ferrocene/Graphene Nanoarchitecture for Supercapacitor Application
  • 2017
  • In: Chemistry - An Asian Journal. - : WILEY-V C H VERLAG GMBH. - 1861-4728 .- 1861-471X. ; 12:8, s. 900-909
  • Journal article (peer-reviewed)abstract
    • The present work highlights the effective H-p interaction between metallocenes ( ferrocene; Fc) and graphene and their stabilization in the presence of polyaniline ( PANI) through pi-pi interactions. The PANI-stabilized Fc@ graphene nanocomposite ( FcGA) resembled an intertwined network-like morphology with high surface area and porosity, which could make it a potential candidate for energy-storage applications. The relative interactions between the components were assessed through theoretical ( DFT) calculations. The specific capacitance calculated from galvanostatic charging/discharging indicated that the PANI-stabilized ter-nary nanocomposite exhibited a maximum specific capacitance of 960 Fg(-) at an energy density of 85 WhKg(-1) and a current density of 1 Ag-. Furthermore, electrochemical impedance spectroscopy (EIS) analysis confirmed the low internal resistance of the as-prepared nanocomposites, which showed improved charge-transfer properties of graphene after incorporation of Fc and stabilization with PANI. Additionally, all electrodes were found to be stable up to 5000 cycles with a specific capacitance retention of 86%, thus demonstrating the good reversibility and durability of the electrode material.
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16.
  • Durisala, Naresh, et al. (author)
  • Determination and classification of the problems experienced by adults with single-sided deafness using ICF classification : an exploratory study using 26 participants
  • 2017
  • In: Clinical Otolaryngology. - : John Wiley & Sons. - 1749-4478 .- 1365-2273. ; 42:3, s. 748-752
  • Journal article (peer-reviewed)abstract
    •  1. Previous studies have shown the application of ICF in classifying hearing problems using open ended questionnaire.2. The present study leveraged on that concept and used ICF in classifying hearing related problems and their effects on life style in adults with single-sided deafness.3. We have used "problem and life effects" questionnaire to which patients were asked to list the problems and effects of hearing loss on their lives.4. Apart from hearing and emotional related problems, use of an open ended questionnaire allowed tapping onto some of the non-auditory problems that these individuals may experience. 5.ICF classification provided basic information on the complex character of single sided deafness and can serve as a key element for rehabilitation.
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17.
  • Gaur, Ashish, et al. (author)
  • A novel approach for industrial concrete defect identification based on image processing and deep convolutional neural networks
  • 2023
  • In: Case Studies in Construction Materials. - : Elsevier. - 2214-5095. ; 19
  • Journal article (peer-reviewed)abstract
    • The preservation of structural integrity and durability is essential for the long-term viability of civil infrastructure projects. Addressing concrete defects promptly is crucial to achieving this objective. In this research, the research proposes a novel method for concrete defect analysis, harnessing the potential of image processing and deep learning techniques. It employs a fusion-based deep convolutional neural network (CNN), amalgamating the features of Inception V3, VGG16, and AlexNet architectures to identify and classify six distinct concrete defect characteristics, namely Cracks, Crazing, Efflorescence, Pop-out, Scaling, and Surface Cracks. Through rigorous training and validation, we thoroughly assess the performance of the proposed fusion-based CNN model. The testing phase reveals precision rates, with Crazing showing the lowest precision at 95%, and Cracks/Pop-outs achieving 98%, while other defect classifications exhibit exceptional 100% precision rates. The overall efficacy of our proposed model is evaluated using accuracy and F1-score metrics. Our findings demonstrate an impressive overall accuracy of 98.31% and an F1-score of 0.98, affirming the robustness and reliability of our approach. The outcomes of this study signify a significant advancement toward accurate and automated detection and classification of concrete defects.
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18.
  • Gupta, Rajeev Kumar, et al. (author)
  • Biochar influences nitrogen and phosphorus dynamics in two texturally different soils
  • 2024
  • In: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14
  • Journal article (peer-reviewed)abstract
    • Nitrogen (N) and phosphorus (P) are vital for crop growth. However, most agricultural systems have limited inherent ability to supply N and P to crops. Biochars (BCs) are strongly advocated in agrosystems and are known to improve the availability of N and P in crops through different chemical transformations. Herein, a soil-biochar incubation experiment was carried out to investigate the transformations of N and P in two different textured soils, namely clay loam and loamy sand, on mixing with rice straw biochar (RSB) and acacia wood biochar (ACB) at each level (0, 0.5, and 1.0% w/w). Ammonium N (NH4-N) decreased continuously with the increasing incubation period. The ammonium N content disappeared rapidly in both the soils incubated with biochars compared to the unamended soil. RSB increased the nitrate N (NO3–N) content significantly compared to ACB for the entire study period in both texturally divergent soils. The nitrate N content increased with the enhanced biochar addition rate in clay loam soil until 15 days after incubation; however, it was reduced for the biochar addition rate of 1% compared to 0.5% at 30 and 60 days after incubation in loamy sand soil. With ACB, the net increase in nitrate N content with the biochar addition rate of 1% remained higher than the 0.5% rate for 60 days in clay loam and 30 days in loamy sand soil. The phosphorus content remained consistently higher in both the soils amended with two types of biochars till the completion of the experiment.
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19.
  • Iragavarapu, Gayathri Priya, et al. (author)
  • Bioprocessing of Waste for Renewable Chemicals and Fuels to Promote Bioeconomy
  • 2023
  • In: Energies. - : MDPI. - 1996-1073. ; 16:9
  • Journal article (peer-reviewed)abstract
    • The world’s rising energy needs, and the depletion of fossil resources demand a shift from fossil-based feedstocks to organic waste to develop a competitive, resource-efficient, and low-carbon sustainable economy in the long run. It is well known that the production of fuels and chemicals via chemical routes is advantageous because it is a well-established technology with low production costs. However, the use of toxic/environmentally harmful and expensive catalysts generates toxic intermediates, making the process unsustainable. Alternatively, utilization of renewable resources for bioprocessing with a multi-product approach that aligns novel integration improves resource utilization and contributes to the “green economy”. The present review discusses organic waste bioprocessing through the anaerobic fermentation (AF) process to produce biohydrogen (H2), biomethane (CH4), volatile fatty acids (VFAs) and medium chain fatty acids (MCFA). Furthermore, the roles of photosynthetic bacteria and microalgae for biofuel production are discussed. In addition, a roadmap to create a fermentative biorefinery approach in the framework of an AF-integrated bioprocessing format is deliberated, along with limitations and future scope. This novel bioprocessing approach significantly contributes to promoting the circular bioeconomy by launching complete carbon turnover practices in accordance with sustainable development goals.
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20.
  • Jena, Naresh Kumar, et al. (author)
  • Solvent-Dependent Structure of the I-3(-) Ion Derived from Photoelectron Spectroscopy and Ab Initio Molecular Dynamics Simulations
  • 2015
  • In: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 21:10, s. 4049-4055
  • Journal article (peer-reviewed)abstract
    • Ab initio molecular dynamics (MD) simulations of the solvation of LiI3 in four different solvents (water, methanol, ethanol, and acetonitrile) are employed to investigate the molecular and electronic structure of the I-3(-) ion in relation to X-ray photoelectron spectroscopy (XPS). Simulations show that hydrogen-bond rearrangement in the solvation shell is coupled to intramolecular bond-length asymmetry in the I-3(-) ion. By a combination of charge analysis and I 4d core-level XPS measurements, the mechanism of the solvent-induced distortions has been studied, and it has been concluded that charge localization mediates intermolecular interactions and intramolecular distortion. The approach involving a synergistic combination of theory and experiment probes the solvent-dependent structure of the I-3(-) ion, and the geometric structure has been correlated with the electronic structure.
  •  
21.
  • Jonstrup, Maria, et al. (author)
  • Decolorization of textile dyes by Bjerkandera sp BOL 13 using waste biomass as carbon source
  • 2013
  • In: Journal of Chemical Technology and Biotechnology. - : Wiley. - 0268-2575. ; 88:3, s. 388-394
  • Journal article (peer-reviewed)abstract
    • BACKGROUND: Phanerochaete chrysosporium, Trametes versicolor and Bjerkandera sp BOL13 were compared for decolorization of azo dyes supplied individually or as a mixture. The dye decolorization was also evaluated during continuous treatment under non-sterile conditions using a lignocellulosic growth substrate. RESULTS: Bjerkandera sp BOL13 showed the highest dye decolorization potential. This fungus was also found to support high decolorization of Remazol Red RR at an initial pH of 4-6 and when using straw as co-substrate. The fungus was evaluated for Remazol Red RR decolorization in a continuously fed packed-bed bioreactor operated under non-sterile conditions with 3 days of hydraulic retention time. When glucose was supplied as growth-substrate, decolorization efficiencies of 65-90% were maintained for 12 days in a bioreactor packed with wooden material. The decolorization efficiency was lower when glucose was not fed to the fungus or when a plastic material was used as packing. Higher manganese peroxidase and laccase activities were also recorded when the wood packing was used. Contamination caused a drop in decolorization efficiency after 17-19 days operation. CONCLUSIONS: The potential of Bjerkandera sp BOL13 for decolorization of azo dyes under non-sterile conditions using lignocellulosic growth substrates was demonstrated. Research is needed to reduce contamination under non-sterile conditions. (c) 2012 Society of Chemical Industry
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22.
  • Jonstrup, Maria, et al. (author)
  • Sequential anaerobic-aerobic treatment of azo dyes: Decolourisation and amine degradability
  • 2011
  • In: Desalination. - : Elsevier BV. - 1873-4464 .- 0011-9164. ; 280:1-3, s. 339-346
  • Journal article (peer-reviewed)abstract
    • The feasibility of sequential anaerobic-aerobic treatment for complete dye degradation was evaluated using three azo dyes, namely Remazol Red RR, Remazol Blue RR and Remazol Yellow RR. The robustness of the anaerobic treatment was investigated in biofilm reactors and the influences of carrier type, hydraulic retention time, dye concentration and dye type were studied. A decolourisation of 98% was obtained in the anaerobic reactors with Poraver carriers whilst decolourisation was slightly lower in the reactors with Kaldnes carriers, which could be attributed to differences in biofilm structure. Almost complete decolourisation could be achieved at dye concentrations between 100 and 2000 mg l(-1) even when the reactors were not adapted to the specific dye. The fate of the metabolites during aerobic treatment was followed: however, only partial degradation of the aromatic amines could be achieved. The metabolites from Remazol Yellow RR auto-oxidised upon exposure to aerobic conditions forming a product, which resisted further degradation. Additional batch tests were conducted using aerobic sludge from a textile and a chemical industry but neither of these inocula was able to completely degrade the recalcitrant amines. This shows the need of a post-treatment to be able to ensure complete amine degradation. (C) 2011 Elsevier B.V. All rights reserved.
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23.
  • Khalid, Muhammad, et al. (author)
  • Frontier molecular, natural bond orbital, UV-VIS spectral study, solvent influence on geometric parameters, vibrational frequencies and solvation energies of 8-hydroxyquinoline
  • 2017
  • In: International Journal of Pharmaceutical Sciences and Research. - : International Journal of Pharmaceutical Sciences and Research. - 0975-8232. ; 8:2, s. 457-469
  • Journal article (peer-reviewed)abstract
    • N-heterocyclic compounds have extensive biological and pharmaceutical applications. 8-Hydroxyquinoline (8-HQ) also plays a significant role in many fields of life. The excellent biological significance of the 8-HQ prompted us to extend the DFT based studies. The frontier molecular orbitals (FMOs), UV-VIS and solvation model based studies remained unknown. Therefore, we intended to study the natural bond orbital, FMOs, UV-VIS, thermodynamic properties and medium influence on solvation energies, dipole moment, FTIR and FT-Raman using polarizable continuum model (PCM) and density-based solvation model (SMD). The electronic properties of molecule were calculated by M06-2X/6-31G (d,P) and B3LYP/6-31G (d,p) level of theories. The solvent influence on the geometric parameters, FT-IR and FT-Raman were studied by B3LYP /6-31G(d) method. A good correspondence is found between the optimized parameters and the reported X-ray data. Natural bond orbital reveals that the maximum stabilization energy reached up to 39.64kJ/mol which is responsible for extra stability of the molecule. In solvated 8-HQ, a significant medium effects on FT-IR and FT-Raman intensities is observed. The intensities enhanced from gas to solvent phase. The solvation free energies are found to be -28.710 and -39.456 kJ/mol in PCM and SMD models respectively. FMOs suggested that this molecule contain less hardness and larger softness values. These findings reveal that the molecule might be bioactive.
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24.
  • Kishore, Kamal, et al. (author)
  • Technological challenges in nanoparticle-modified geopolymer concrete : a comprehensive review on nanomaterial dispersion, characterization techniques and its mechanical properties
  • 2023
  • In: Case Studies in Construction Materials. - : Elsevier. - 2214-5095. ; 19
  • Journal article (peer-reviewed)abstract
    • The use of geopolymer-based concrete has many advantages over conventional cement concrete. Geopolymer, which derives its basic ingredients from industrial waste, has considerable opportunity to dump the industrial waste and reduce the carbon dioxide emissions that could be emitted during cement manufacturing. Geopolymer concrete is potentially suitable for structural engineering applications; however, its unskilled manufacturing leads to several deficits such as cracking, weak mechanical characteristics, and reduced serviceability of the geopolymer structures. Nanomaterials are now being applied and developed in the realm of materials, where they have shown strong filling effects on composite materials that significantly enhance the integrity of composite materials. Research into how nanomaterials might enhance the performance of geopolymer concrete (GPC) in engineering applications is gaining a lot of attention. The past literature revealed that the GPC characteristics can be enhanced by adding nanoparticles; thereby increasing its engineering applications in practical usage. This study highlighted the primary technical issues of nanomaterial-or modified GPC during the last decade in light of widespread fascination with the subject and the need to provide an up-to-date and comprehensive study for future related research. This review study has covered the most up-to-date information and data on geopolymer concrete, including its methods of dispersion, characterization methodologies, interface mechanisms of nanoparticles, and mechanical characteristics. Concurrently, the limitations and major issues associated with using nanomaterials to modify GPC in practical applications are thoroughly examined. Finally, the future potential and difficulties of this area of study are highlighted.
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25.
  • Kumar, Radhakrishnan Naresh, et al. (author)
  • Old Landfill Leachate and Municipal Wastewater Co-Treatment by Sequencing Batch Reactor Combined with Coagulation-Flocculation Using Novel Flocculant
  • 2023
  • In: Sustainability. - : MDPI AG. - 2071-1050. ; 15:10
  • Journal article (peer-reviewed)abstract
    • The use of novel flocculants in combination with a sequencing batch reactor (SBR) for the treatment of landfill leachate and municipal wastewater has been shown to be an effective method for reducing polluted effluents. Co-treatment of landfill leachate with a mixture of municipal wastewater was performed at 5%, 10%, 15% and 20% in SBR and effluent was treated by coagulation-flocculation. SBR with 6 d hydraulic retention time (HRT) and 30 d solids retention time (SRT) removed 58 to 70% COD, 86 to 93% ammonia, 76 to 83% nitrate and 69 to 95% phosphate. Coagulation-flocculation with different dosages of alum and ferric chloride with polyacrylamide grafted gum ghatti (GGI-g-PAM) as a novel flocculant was used for chemical oxygen demand (COD), turbidity, total suspended solids (TSS) and color removal. Maximum COD removal was at 20% leachate, which was 74% with alum at 2800 mg/L and 77% with ferric chloride at 470 mg/L. Alum and ferric chloride with GGI-g-PAM flocculant removed 96% and 82% of turbidity and 80% and 82% TSS, respectively. At 20% leachate, combined treatment with SBR and coagulation-flocculation resulted in the total removal of 89% COD, 83% ammonia, 82% nitrate 98% turbidity and 93% TSS with alum. The combined treatment with ferric chloride resulted in a removal of 90% COD, 86% ammonia, 83% nitrate, 98% turbidity and 94% TSS. Except for nitrate combined treatment with both the coagulants at 20% landfill leachate to municipal wastewater ratio removed COD, ammonia, phosphate and TSS to a level that met international standards for discharges to inland surface water. As such, the use of new flocculants with SBR can help reduce water pollution from landfill leachate and municipal wastewater. In addition to coagulation-flocculation, other physico-chemical processes can also be studied as post-treatment options for the co-treatment of wastewater mixture.
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26.
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27.
  • Kumar Wagri, Naresh, et al. (author)
  • An overview of the machinability of alloy steel
  • 2022
  • In: Materials Today. - : Elsevier. - 2214-7853. ; 62, s. 3771-3781
  • Journal article (peer-reviewed)abstract
    • Machinability is an important aspect for the machining of any materials. In general, it is controlled by means of tool life, surface roughness, power consumption, chip morphology, cutting forces, cutting fluid and material removal rate. Furthermore, it is also affected the microstructure, grain size, hardness, yield, tensile strength and chemical composition of the work piece material and tool materials. Advanced materials such as alloy steel, structural ceramics, and hardened steel are difficult to machine using conventional tool materials. The machining parameters such as depth of cut, cutting velocity and feed rate play a very important role to achieve high quality of surface finish on the machined surface. High interface temperatures at the tool tip and work piece material resulted poor surface finish and increases cutting forces and tool wear. A high cutting speeds with high feed and depth of cut causes high heat generation which reduces the tool substrates bonding strength resulting in accelerated tool wear and reducing tool life. In this article influence of heat treatment to enhance machinability alloy steel reviewed in terms of tool life, surface roughness, cutting forces and chip morphology. This article will be very useful for the students, research scholar and industrialist working in the area of machining.
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28.
  • Kumar Wagri, Naresh, 1988- (author)
  • Assessment of bio-based fuel ash effects on magnesia refractory materials in quicklime production kilns
  • 2023
  • Doctoral thesis (other academic/artistic)abstract
    • Limestone is calcined into quicklime in lime kilns at temperatures above 1000°C. Heat is supplied through combustion inside the kilns, which are insulated with a lining of refractory bricks to mitigate heat loss and to protect the kiln from the hot, chemically aggressive, and mechanically abrasive environment. While magnesia bricks have proven to be effective lining materials, they are still susceptible to extensive wear in lime kilns, especially in the burn zone. Refractory corrosion, in particular, can occur when melted fuel ash infiltrates the refractory materials through pores and small cracks. This resultant wear can lead to high maintenance and operational costs, often due to unplanned kiln shutdowns.To reduce the release of fossil-based carbon dioxide into the atmosphere from lime production kilns, there is a growing interest in introducing bio-based fuels with only relatively minor modifications to the process. Biomass fuels can be sourced from bio-based waste streams from industries or be specifically cultivated for combustion. However, the ash content and properties of bio-based fuels tend to be problematic from an ash chemistry perspective. Therefore, before introducing a new fuel source, it is essential to investigate its potential effects on the kiln lining material. In this thesis work, the interactions between melted olive pomace ash and coal ash with commercially available magnesia refractory materials, primarily composed of periclase (MgO) with minor amounts of spinel (MgAl2O4), were studied. A procedure for quantifying the intrusion depths was described. Refractory samples were exposed to the fuel ashes under a simulated lime kiln atmosphere with high CO2 levels at 1200 and 1400°C for 15 and 60 minutes. Cold crushing strength tests were conducted on refractory samples exposed to coal and olive pomace ash, along with CaO powder, at 1400°C for 96 hours. Additionally, postmortem analyses of spent MgO-based refractory bricks were carried out to investigate their chemical characterization and resistance to slag attack after serving as part of the lining in a quick lime rotary kiln for six months.The morphology and elemental compositions of the exposed samples were examined using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Crystalline phases were investigated with powder X-ray diffraction. Thermodynamic equilibrium calculations were performed to further investigate the ash’s melting behavior in contact with the refractories.The results indicated that the potassium-rich olive pomace ash exhibited a greater tendency to infiltrate compared to the silicon-rich coal ash, while the latter formed a glassy melt layer on top of the refractory samples. The ash slags primarily infiltrated through the porous matrix and grain boundaries of the refractory materials. Also, refractory phases were observed in both types of ashes, indicating migration of refractory constituents. K2MgSiO4 phase was found in the olive pomace ash residues on top of the samples, both for the 1200°C and 1400°C exposures. Similarly, Al6Si2O13 phase was dominant in the residual coal ash, in both the 1200°C and 1400°C exposed samples. None of these phases were present in the original ashes.The results of the postmortem analysis revealed that there was no potassium (K) from the fuel ash present on the hot side of the refractory bricks. However, some K was detected in the middle and back parts of the bricks. On the other hand, some phases, possibly connected to degradation, could be found on the hot side of the bricks, where most of the wear was observed.The crushing strengths increased after exposure for all samples, except for those exposed exclusively to coal ash. One possible explanation for this is that the refractory materials exhibited a sintered structure, as a result of their interaction with the ashes and CaO. However, in the samples exposed to coal ash, forsterite (Mg2SiO4) was identified, which can be considered a corrosion product.
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29.
  •  
30.
  • Kumar Wagri, Naresh, et al. (author)
  • High temperature interactions between coal ash and MgO-based refractories in lime kiln conditions
  • 2023
  • In: Fuel. - : Elsevier. - 0016-2361 .- 1873-7153. ; 342
  • Journal article (peer-reviewed)abstract
    • Magnesium oxide (MgO)-based refractories are commonly used in quicklime and cement rotary kilns. At the high temperatures in the kiln burn zone, the infiltration of molten fuel ash into the refractory can occur. Subsequent chemical interactions can cause refractory wear that inflicts high maintenance costs and loss of production. To improve refractory reliability, it is necessary to increase the understanding of the interactions between fuel ash slag and refractory liner materials. Three commercially available MgO-based refractory materials were exposed to coal ash at 1200 °C and 1400 °C for between 15 and 60 min under a CO2-rich gaseous environment. Hot slag from the coal ash infiltrated the refractories and the infiltration depths were estimated with scanning electron microscope with energy dispersive X-ray spectroscopy. Based on detailed elemental and microstructure analyses, the interactions between ash and refractory were examined. Molten silicates infiltrated the refractory through grain boundaries and pores into depths of up to 2.8 mm. Powder X-ray diffraction of the exposed refractory samples indicated that MgO grains reacted with SiO2-containing phases to form Mg2SiO4. This was identified as a corrosion product whose formation was supported by thermochemical equilibrium calculations. Elevated Mg content was found in the ash residue on top of the samples, indicating the dissolution or dislocation of refractory components. In addition, phases such as MgO were identified in the ash residue.
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31.
  • Kumar Wagri, Naresh, et al. (author)
  • High temperature interactions between K-rich biomass ash and MgO-based refractories
  • 2023
  • In: Journal of the European Ceramic Society. - : Elsevier. - 0955-2219 .- 1873-619X. ; 43:8, s. 3770-3777
  • Journal article (peer-reviewed)abstract
    • MgO-based refractories are used in lime kilns to withstand the high temperature and chemical environment. Efforts to reduce CO2 emissions have led to an increased interest to use bio-based fuels as alternatives to traditional fossil sources. The potential for refractory corrosion from a potassium-rich biomass ash was investigated by studying the infiltration of olive pomace ash into magnesia/spinel refractories. Refractory samples were exposed to the ash at up to 1400 °C for 15–60 min in a CO2–rich atmosphere. Molten ash infiltrated the refractories through pores and grain boundaries to a depth of up to 9.6 mm, which was quantified with a new systematic procedure. The phase KAlO2 was identified inside the refractories after exposure, indicating an attack of spinel components by potassium. Phases found in the ash residues also indicated the migration of refractory constituents. Thermochemical equilibrium calculations were also used to investigate the ash/refractory chemistry.
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32.
  • Kumar Wagri, Naresh, et al. (author)
  • Interaction of olive pomace ash and coal ash with magnesium oxide based refractories
  • 2022
  • In: Proceedings of the 28th International Conference on the Impact of Fuel Quality on Power Production and the Environment. - : Department of Applied Physics and Electronics, Umeå University.
  • Conference paper (other academic/artistic)abstract
    • In quicklime production, limestone is calcined at temperatures above 1000°C, depending on the desired product quality. Heat is supplied to the process from combustion inside the kilns that are insulated to reduce heat loss. The kilns are lined with insulating refractory bricks to withstand the hot, chemically aggressive, and mechanically abrasive environment. Magnesia bricks have emerged as well-performinglining materials, but they are still prone to extensive wear in kilns that are operated at higher temperatures. In particular, refractory corrosion can be caused by fuel ash infiltration that results inmaterial wear, which can incur high maintenance and operational costs through unplanned shutdowns of the kilns. At the same time, to reduce the release of fossil-based carbon to the atmosphere, it is of interest to introduce bio-based fuels into the kilns with only relatively small modifications to the process. Biobased waste streams from existing industries are preferable rather than biomass grown with the sole purpose of combustion. The ash content and properties of these types of waste residues do, however, tend to be problematic from a fuel ash chemistry point of view. Therefore, before introducing a new fuel, their potential effects on kiln lining material should be investigated. In this study, the infiltration of olivepomace ash and coal ash into commercially available refractory materials composed of mainly periclase(MgO) with minor amounts of spinel (MgAl2O4) were compared. They were exposed to the fuel ashes under a simulated lime kiln high CO2 atmosphere at 1200 and 1400°C for 15 and 60 minutes. The morphology and elemental composition of the exposed samples were investigated with scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy. Ash-forming elements infiltrated the porous parts of the materials. The analytical results are complemented with thermodynamic equilibrium calculations to investigate the ash melting behavior. Crystalline phases in the residual ashes were investigated with X-ray diffraction. Refractory phases could be found in both ashes, indicating migration of refractory constituents. Olive pomace ash formed new crystalline compounds together with the refractory components whereas this was not observed for the coal ash, indicating that the former is more of a risk for material failure.  
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33.
  • Kumawat, Naresh Kumar, et al. (author)
  • Blue perovskite light-emitting diodes: progress, challenges and future directions
  • 2019
  • In: Nanoscale. - : ROYAL SOC CHEMISTRY. - 2040-3364 .- 2040-3372. ; 11:5, s. 2109-2120
  • Research review (peer-reviewed)abstract
    • Metal halide perovskites have excellent optical and electrical properties and can be easily processed via low-cost solution-based techniques like blade-coating and inkjet printing, promising a bright future for various optoelectronic applications. Recently, encouraging progress has been made in perovskite light-emitting diodes (PeLEDs). Green, red, and near-infrared PeLEDs have achieved high external quantum efficiencies of more than 20%. However, as historically blue electroluminescence remains challenging in all previous LED technologies, we are witnessing a similar case with the development of blue PeLEDs, an essential part of displays and solid-state lighting, which lag far behind those of their counterparts. Herein, we review the recent progress of blue PeLEDs and discuss the main challenges including colour instability, poor photoluminescence efficiency and emission quenching by interlayers. Future directions are provided to facilitate the development of efficient blue PeLEDs.
  •  
34.
  • Kumawat, Naresh Kumar, et al. (author)
  • Metal Doping/Alloying of Cesium Lead Halide Perovskite Nanocrystals and their Applications in Light-Emitting Diodes with Enhanced Efficiency and Stability
  • 2019
  • In: Israel Journal of Chemistry. - : WILEY-V C H VERLAG GMBH. - 0021-2148 .- 1869-5868. ; 59:8, s. 695-707
  • Research review (peer-reviewed)abstract
    • Metal halide perovskite nanocrystals (NCs) have demonstrated great advances for light-emitting diodes (LEDs) applications, owing to their excellent optical, electrical properties and cost-effective solution-processing potentials. Tremendous progress has been made in perovskite NCs-based LEDs during the past several years, with the external quantum efficiency (EQE) boosted to over 20 %. Recently, metal doping/alloying strategy has been explored to finely tune the optoelectronic properties and enhance material stability of perovskite NCs, leading to further improved device efficiency and stability of the obtained perovskite NCs-based LEDs. In this review, we summarize recent progress on the metal doping/alloying of perovskite NCs and their applications in LEDs. We focus on the effects of different metal doping strategies on the structural and optoelectronic properties of the perovskite NCs. In addition, several works on high-performance LEDs based on metal doped/alloyed perovskite NCs with different light emission colours are highlighted. Finally, we present an outlook on employing metal doping/alloying strategies to further improve the device efficiency and stability of LEDs based on perovskite NCs.
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35.
  • Kumawat, Naresh Kumar, et al. (author)
  • Mobile ions determine the luminescence yield of perovskite light-emitting diodes under pulsed operation
  • 2021
  • In: Nature Communications. - : NATURE PORTFOLIO. - 2041-1723. ; 12:1
  • Journal article (peer-reviewed)abstract
    • The external quantum efficiency of perovskite light-emitting diodes (PeLEDs) has advanced quickly during the past few years. However, under pulsed operation, an operation mode which is important for display and visible light communication, the performance of PeLEDs changes a lot and requires in-depth understanding to facilitate these applications. Here, we report the response of PeLEDs under pulsed operation in the range of 10 Hz to 20 kHz. Beyond transient effects in the low frequencies, we find that for higher frequencies (>500 Hz) the transient electroluminescence intensity depends strongly on the duty cycle. This feature is much more pronounced and of different origin than that in conventional LEDs. We rationalise our experimental observations using a mathematical model and assign these features to the effect of mobile ionic charges in the perovskite. Our work also provides important implications for the operation of PeLEDs under the steady state, where accumulation of mobile ions at the interfaces could be beneficial for high electroluminescence yields but harmful for the long-term stability. 
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36.
  • Lindahl, Johanna, et al. (author)
  • Serological evidence of Brucella infections in dairy cattle in Haryana, India
  • 2018
  • In: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 8:1
  • Journal article (peer-reviewed)abstract
    • Background: In India, milk production is important for both the economy and the provision of nutritious food. However, the productivity of the livestock is affected by circulating infectious diseases, and some zoonotic diseases, such as brucellosis, may cause a heavy impact on the farm as the disease cause abortions and reproductive failures in bovines, with chronic febrile illness in humans.Methods: 249 dairy farms in the state of Haryana, India, were interviewed, and collected raw milk from 81 were analyzed for antibodies towards Brucella abortus.Results: More samples were positive using milk ring test (MRT) (55.6%, 45/81) than using enzyme-linked immunosorbent assay (ELISA) (29.6%, 24/81), with all ELISA positive samples also positive in MRT. The ELISA results were used for risk factor analyses. Seropositive farms were significantly (p = 0.015) larger than seronegative, with an average 7.9 cattle, compared to 4.9. Seropositive farms were more likely to report stillbirth occurring the last year, and a significantly higher proportion of seropositive farms reported retained placenta (odds ratio 5.2).Conclusion: This study showed that Brucella seroprevalence is high among farms in Haryana, and a control program is needed to ensure improved human and animal health, as well as improved livestock productivity.
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37.
  • Lindström, Elin, et al. (author)
  • Regularized reconstruction of digital time-of-flight Ga-68-PSMA-11 PET/CT for the detection of recurrent disease in prostate cancer patients
  • 2019
  • In: Theranostics. - : Ivyspring International Publisher. - 1838-7640. ; 9:12, s. 3476-3484
  • Journal article (peer-reviewed)abstract
    • Accurate localization of recurrent prostate cancer (PCa) is critical, especially if curative therapy is intended. With the aim to optimize target-to-background uptake ratio in Ga-68-PSMA-11 PET, we investigated the image quality and quantitative measures of regularized reconstruction by block-sequential regularized expectation maximization (BSREM).Methods: The study encompassed retrospective reconstruction and analysis of 20 digital time-of-flight (TOF) PET/CT examinations acquired 60 min post injection of 2 MBq/kg of Ga-68-PSMA-11 in PCa patients with biochemical relapse after primary treatment. Reconstruction by ordered-subsets expectation maximization (OSEM; 3 iterations, 16 subsets, 5 mm gaussian postprocessing filter) and BSREM (beta-values of 100-1600) were used, both including TOF and point spread function (PSF) recovery. Background variability (BV) was measured by placing a spherical volume of interest in the right liver lobe and defined as the standard deviation divided by the mean standardized uptake value (SUV). The image quality was evaluated in terms of signal-to-noise ratio (SNR) and signal-to-background ratio (SBR), using SUVmax of the lesions. A visual assessment was performed by four observers.Results:OSEM reconstruction produced images with a BV of 15%, whereas BSREM with a beta-value above 300 resulted in lower BVs than OSEM (36% with beta 100, 8% with beta 1300). Decreasing the acquisition duration from 2 to 1 and 0.5 min per bed position increased BV for both reconstruction methods, although BSREM with beta-values equal to or higher than 800 and 1200, respectively, kept the BV below 15%. In comparison of BSREM with OSEM, the mean SNR improved by 25 to 66% with an increasing beta-value in the range of 200-1300, whereas the mean SBR decreased with an increasing beta-value, ranging from 0 to 125% with a beta-value of 100 and 900, respectively. Decreased acquisition duration resulted in beta-values of 800 to 1000 and 1200 to 1400 for 1 and 0.5 min per bed position, respectively, producing improved image quality measures compared with OSEM at a full acquisition duration of 2 min per bed position. The observer study showed a slight overall preference for BSREM beta 900 although the interobserver variability was high.Conclusion:BSREM image reconstruction with beta-values in the range of 400-900 resulted in lower BV and similar or improved SNR and SBR in comparison with OSEM.
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38.
  •  
39.
  • Mirabediny, Maryam, et al. (author)
  • Effective PFAS degradation by electrochemical oxidation methods-recent progress and requirement
  • 2023
  • In: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 321
  • Journal article (peer-reviewed)abstract
    • The presence of per-and poly-fluoroalkyl substances (PFASs) in water is of global concern due to their high stability and toxicity even at very low concentrations. There are several technologies for the remediation of PFASs, but most of them are inadequate either due to limited effectiveness, high cost, or production of a large amount of sludge. Electrochemical oxidation (EO) technology shows great potential for large-scale application in the degradation of PFASs due to its simple procedure, low loading of chemicals, and least amount of waste. Here, we have reviewed the recent progress in EO methods for PFAS degradation, focusing on the last 10 years, to explore an efficient, cost-effective, and environmentally benign remediation technology. The effects of important parameters (e.g., anode material, current density, solution pH, electrolyte, plate distance, and electrical connector type) are summarized and evaluated. Also, the energy consumption, the consequence of different PFASs functional groups, and water matrices are discussed to provide an insight that is pivotal for developing new EO materials and technologies. The proposed degradation pathways of shorter-chain PFAS by-products during EO of PFAS are also discussed.
  •  
40.
  • Mirabediny, Maryam, et al. (author)
  • Fast reductive defluorination of branched perfluorooctane sulfonic acids by cobalt phthalocyanine : electrochemical studies and mechanistic insights
  • 2024
  • In: Environmental Science. - 2053-1400 .- 2053-1419. ; 10:1, s. 216-227
  • Journal article (peer-reviewed)abstract
    • Branched perfluorooctane sulfonic acid (PFOS) is recognized as a threatening environmental pollutant due to its high persistence and bioaccumulation in various environmental matrices as well as for its toxic effects on humans and wildlife even at very low concentrations. This study reports the first investigation of branched PFOS defluorination catalyzed by metal phthalocyanines. The reaction conditions were optimized using different reductants and temperatures. CobaltII phthalocyanine, when combined with TiIII citrate as a reducing agent, was able to defluorinate 10.9% of technical PFOS within 8 hours. In contrast, vitamin B12 only showed 2.4% defluorination during the same time period, under similar conditions. The defluorination mediated by the cobaltII phthalocyanine and TiIII citrate system corresponds to 54.5% of all branched PFOS isomers (br-PFOS isomers). Isomer-specific degradation was also investigated via high-resolution LC-orbitrap followed by their relative rates. The difference in catalytic efficacy of various phthalocyanine complexes is rationalized by their structures and electrochemical response. Lastly, a new defluorination mechanism is proposed based on the newly detected degradation products after the phthalocyanine treatment and previous studies. CobaltII phthalocyanine in the presence of TiIII citrate acts as an efficient reducing agent which was able to defluorinate 54.5% of all branched PFOS isomers.
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41.
  • Naqvi, Syeda Rabab, et al. (author)
  • Exploring two-dimensional M2NS2 (M = Ti, V) MXenes based gas sensors for air pollutants
  • 2020
  • In: Applied Materials Today. - : Elsevier. - 2352-9407. ; 19
  • Journal article (peer-reviewed)abstract
    • Albeit a very recent development, Mxenes have offered numerous potential avenues for researchers from physics, chemistry and materials science. Here in, we have explored S-terminated M2N (M = Ti, V) MXenes, which are one of the lightest and thinnest members of the MXene family, for gas sensing applications. We performed spin-polarized DFT calculations with vdW correction to investigate the sensing propensity of several gases such as CH4, CO, CO2, NH3, NO, NO2, H2S, and SO2 on M2NS2 sheets. The adsorption kinetics, charge transfer, electronic density of states (DOS) and electronic transport behaviors are investigated in relation to M2NS2 Mxene based nanoscale gas sensor. Among all the gases under consideration, NO, and NO2 exhibit superior sensitivity towards 2D nitride MXenes. Charge transfer analysis reveals that the considerable quantity of charge is transferred from NO, and NO2 gas molecules to Ti2NS2 and V2NS2 MXene sheets, respectively. Spin-polarized DOS reveals that pristine non-magnetic nitride Mxenes transform to magnetic systems upon NO and NO2 adsorption. By computing the electronic transport properties in the form of I–V characteristics for adsorbed gases on M2NS2 and comparing it against the pristine Mxene sheets, distinct changes in I–V relationships can be identified which further substantiate the promising role of Mxenes for gas sensing applications.
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42.
  • Naresh, R. K., et al. (author)
  • Long-term application of agronomic management strategies effects on soil organic carbon, energy budgeting, and carbon footprint under rice–wheat cropping system
  • 2024
  • In: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14:1
  • Journal article (peer-reviewed)abstract
    • In the plains of western North India, traditional rice and wheat cropping systems (RWCS) consume a significant amount of energy and carbon. In order to assess the long-term energy budgets, ecological footprint, and greenhouse gas (GHG) pollutants from RWCS with residual management techniques, field research was conducted which consisted of fourteen treatments that combined various tillage techniques, fertilization methods, and whether or not straw return was present in randomized block design. By altering the formation of aggregates and the distribution of carbon within them, tillage techniques can affect the dynamics of organic carbon in soil and soil microbial activity. The stability of large macro-aggregates (> 2 mm), small macro-aggregates (2.0–2.25 mm), and micro-aggregates in the topsoil were improved by 35.18%, 33.52%, and 25.10%, respectively, over conventional tillage (0–20 cm) using tillage strategies for conservation methods (no-till in conjunction with straw return and organic fertilizers). The subsoil (20–40 cm) displayed the same pattern. In contrast to conventional tilling with no straw returns, macro-aggregates of all sizes and micro-aggregates increased by 24.52%, 28.48%, and 18.12%, respectively, when conservation tillage with organic and chemical fertilizers was used. The straw return (aggregate-associated C) also resulted in a significant increase in aggregate-associated carbon. When zero tillage was paired with straw return, chemical, and organic fertilizers, the topsoil's overall aggregate-associated C across all aggregate proportions increased. Conversely, conventional tillage, in contrast to conservation tillage, included straw return as well as chemical and organic fertilizers and had high aggregate-associated C in the subsurface. This study finds that tillage techniques could change the dynamics of microbial biomass in soils and organic soil carbon by altering the aggregate and distribution of C therein.
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43.
  • Odelius, Karin, et al. (author)
  • Porosity and Pore Size Regulate the Degradation Product Profile of Polylactide
  • 2011
  • In: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 12:4, s. 1250-1258
  • Journal article (peer-reviewed)abstract
    • Porosity and pore size regulated the degradation rate and the release of low molar mass degradation products from porous polylactide (PLA) scaffolds. PLA scaffolds with porosities above 90% and different pore size ranges were subjected to hydrolytic degradation and compared to their solid analog. The solid film degraded fastest and the degradation rate of the porous structures decreased with decreasing pore size. Degradation products were detected earlier from the solid films compared to the porous structures as a result of the additional migration path within the porous structures. An intermediate degradation rate profile was observed when the pore size range was broadened. The morphology of the scaffolds changed during hydrolysis where the larger pore size scaffolds showed sharp pore edges and cavities on the scaffold surface. In the scaffolds with smaller pores, the pore size decreased during degradation and a solid surface was formed on the top of the scaffold. Porosity and pore size, thus, influenced the degradation and the release of degradation products that should be taken into consideration when designing porous scaffolds for tissue engineering.
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44.
  • Padhan, Smita, et al. (author)
  • Investigation on surface integrity in hard turning of AISI 4140 steel with SPPP-AlTiSiN coated carbide insert under nano-MQL
  • 2023
  • In: Lubricants. - : MDPI. - 2075-4442. ; 11:2
  • Journal article (peer-reviewed)abstract
    • The machined surface integrity in the turning of hardened steels is adversely influenced by heat generation and friction which requires pacification of the temperature by the effective cooling-lubrication approach and cutting tool performance. The present research analyzes the surface integrity of hardened AISI 4140 steel during turning with recently developed scalable pulsed power plasma SPPP-AlTiSiN coated carbide tool under nanofluid-assisted minimum quantity lubrication (MQL). Zinc oxide nanoparticles and environmentally friendly radiator coolant are mixed to prepare the nano cutting fluid. This analysis addresses the various aspects of surface integrity concerning surface morphology, machined surface hardness, residual stress and white layer development, and machined surface finish under varying cutting parameters (depth of cut, speed, feed, nose radius). Response surface methodology (RSM) is suggested to predict and to optimize the surface roughness in hard turning. Thereafter, the predictive modelling and optimization results are implemented for economic analysis. According to the findings of the experiments, with a contribution of 58.18%, the feed rate possesses a high impact on the surface finish, followed by the nose radius (12.32%) and speed (0.85%). Consequently, the machined surface quality improved with the increase of the nose radius because of the minimum tool wear and due to the increase of the effective length of the cutting edge. At optimum cutting conditions, the tool life of SPPP-AlTiSiN coated carbide insert is noted as 46 minutes under nanofluid-MQL and consequently, it estimated the overall machining cost per component as Rs.23.12 in Indian currency.
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45.
  • Paladugu, Sri Ram Murthy, et al. (author)
  • A Comprehensive Review of Self-Healing Polymer, Metal, and Ceramic Matrix Composites and Their Modeling Aspects for Aerospace Applications
  • 2022
  • In: Materials. - : Mdpi. - 1996-1944. ; 15:23
  • Research review (peer-reviewed)abstract
    • Composites can be divided into three groups based on their matrix materials, namely polymer, metal and ceramic. Composite materials fail due to micro cracks. Repairing is complex and almost impossible if cracks appear on the surface and interior, which minimizes reliability and material life. In order to save the material from failure and prolong its lifetime without compromising mechanical properties, self-healing is one of the emerging and best techniques. The studies to address the advantages and challenges of self-healing properties of different matrix materials are very limited; however, this review addresses all three different groups of composites. Self-healing composites are fabricated to heal cracks, prevent any obstructed failure, and improve the lifetime of structures. They can self-diagnose their structure after being affected by external forces and repair damages and cracks to a certain degree. This review aims to provide information on the recent developments and prospects of self-healing composites and their applications in various fields such as aerospace, automobiles etc. Fabrication and characterization techniques as well as intrinsic and extrinsic self-healing techniques are discussed based on the latest achievements, including microcapsule embedment, fibers embedment, and vascular networks self-healing.
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46.
  • Purrington, Kristen S., et al. (author)
  • Genome-wide association study identifies 25 known breast cancer susceptibility loci as risk factors for triple-negative breast cancer
  • 2014
  • In: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 35:5, s. 1012-1019
  • Journal article (peer-reviewed)abstract
    • In a genome-wide scan, we show that 30 variants in 25 genomic regions are associated with risk of TN breast cancer. Women carrying many of the risk variants may have 4-fold increased risk relative to women with few variants.Triple-negative (TN) breast cancer is an aggressive subtype of breast cancer associated with a unique set of epidemiologic and genetic risk factors. We conducted a two-stage genome-wide association study of TN breast cancer (stage 1: 1529 TN cases, 3399 controls; stage 2: 2148 cases, 1309 controls) to identify loci that influence TN breast cancer risk. Variants in the 19p13.1 and PTHLH loci showed genome-wide significant associations (P < 5 x 10(-) (8)) in stage 1 and 2 combined. Results also suggested a substantial enrichment of significantly associated variants among the single nucleotide polymorphisms (SNPs) analyzed in stage 2. Variants from 25 of 74 known breast cancer susceptibility loci were also associated with risk of TN breast cancer (P < 0.05). Associations with TN breast cancer were confirmed for 10 loci (LGR6, MDM4, CASP8, 2q35, 2p24.1, TERT-rs10069690, ESR1, TOX3, 19p13.1, RALY), and we identified associations with TN breast cancer for 15 additional breast cancer loci (P < 0.05: PEX14, 2q24.1, 2q31.1, ADAM29, EBF1, TCF7L2, 11q13.1, 11q24.3, 12p13.1, PTHLH, NTN4, 12q24, BRCA2, RAD51L1-rs2588809, MKL1). Further, two SNPs independent of previously reported signals in ESR1 [rs12525163 odds ratio (OR) = 1.15, P = 4.9 x 10(-) (4)] and 19p13.1 (rs1864112 OR = 0.84, P = 1.8 x 10(-) (9)) were associated with TN breast cancer. A polygenic risk score (PRS) for TN breast cancer based on known breast cancer risk variants showed a 4-fold difference in risk between the highest and lowest PRS quintiles (OR = 4.03, 95% confidence interval 3.46-4.70, P = 4.8 x 10(-) (69)). This translates to an absolute risk for TN breast cancer ranging from 0.8% to 3.4%, suggesting that genetic variation may be used for TN breast cancer risk prediction.
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47.
  • Regula, Naresh Kumar, et al. (author)
  • Comparison of Ga-68-PSMA PET/CT with fluoride PET/CT for detection of bone metastatic disease in prostate cancer
  • 2022
  • In: European Journal of Hybrid Imaging. - : Springer Nature. - 2510-3636. ; 6:1
  • Journal article (peer-reviewed)abstract
    • Background F-18-NaF positron emission tomography/computed tomography (fluoride PET/CT) is considered the most sensitive technique to detect bone metastasis in prostate cancer (PCa). Ga-68-PSMA-11 (PSMA) PET/CT is increasingly used for staging of PCa. This study primarily aimed to compare the diagnostic performance of fluoride PET/CT and gallium-based PSMA PET/CT in identifying bone metastasis followed by a comparison of PSMA PET/CT with contrast-enhanced CT (CE-CT) in identifying soft tissue lesions as a secondary objective. Methods Twenty-eight PCa patients with high suspicion of disseminated disease following curative treatment were prospectively evaluated. PET/CT examinations using fluoride and PSMA were performed. All suspicious bone lesions were counted, and the tracer uptake was measured as standardized uptake values (SUV) for both tracers. In patients with multiple findings, ten bone lesions with highest SUVmax were selected from which identical lesions from both scans were considered for direct comparison of SUVmax. Soft tissue findings of local and lymph node lesions from CE-CT were compared with PSMA PET/CT. Results Both scans were negative for bone lesions in 7 patients (25%). Of 699 lesions consistent with skeletal metastasis in 21 patients on fluoride PET/CT, PSMA PET/CT identified 579 lesions (83%). In 69 identical bone lesions fluoride PET/CT showed significantly higher uptake (mean SUVmax: 73.1 +/- 36.8) compared to PSMA PET/CT (34.5 +/- 31.4; p < 0.001). Compared to CE-CT, PSMA PET/CT showed better diagnostic performance in locating local (96% vs 61%, p = 0.004) and lymph node (94% vs 46%, p < 0.001) metastasis. Conclusion In this prospective comparative study, PSMA PET/CT detected the majority of bone lesions that were positive on fluoride PET/CT. Further, this study indicates better diagnostic performance of PSMA PET/CT to locate soft tissue lesions compared to CE-CT.
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48.
  • Regula, Naresh Kumar, et al. (author)
  • Dynamic Imaging of Prostate Cancer with 11C-acetate PET/CT
  • 2017
  • In: Journal of Nuclear Medicine. - 0161-5505 .- 1535-5667. ; 58:S1
  • Journal article (other academic/artistic)abstract
    • Objectives: Dynamic 11C-acetate PET/CT can be used to study tissue perfusion and carbon flux simultaneously, but studies in cancer are limited. We investigated the kinetics of 11C-acetate in prostate cancer subjects using parametric images with an image-derived input function (IDIF).Methods: Twenty-one patients with newly diagnosed low-moderate risk prostate cancer were studied. All underwent pelvic MRI. Dynamic 11C-acetate (5 MBq/kg) PET/CT of the pelvis was acquired for 32 minutes with 32 time frames. An IDIF was acquired from iliac vessels with multiple small regions of interest (ROIs) and a standardized metabolite correction. Parametric images of K1 (extraction), k2 (oxidative metabolism) and Vd (=K1/k2, anabolic metabolism defined as carbon retention) were constructed using a one-tissue compartment model. ROIs of the largest cancer region in each patient and normal prostate tissue were drawn using information from MRI (T2 and DWI images) and from post-surgical histopathology of whole prostate sections (n=7).Results: Mean PSA was 8.3±3.9. Median Gleason Sum was 6 (range 5-7). K1, Vd and SUVs were higher in cancerous regions compared to normal prostate for all patients (p<0.001). PSA correlated to early SUV (r=0.50, p=0.02) and K1 (r=0.48, p=0.03). Early and late SUVs were correlated to Vd (r>0.76, p<0.001) and K1 (r>0.61, p<0.005).Conclusion: Parametric images could be used to visualize the 11C-acetate kinetics of the prostate. In this cohort of relatively low-risk cancers, PSA values were related to cancer perfusion. SUV of cancerous regions at any time point is primarily associated with anabolic metabolism. Research Support: Swedish Cancer Foundation (Cancerfonden)
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49.
  • Regula, Naresh Kumar, 1985- (author)
  • PET in Prostate Cancer – Detection, Tumour Biology and Prognosis
  • 2020
  • Doctoral thesis (other academic/artistic)abstract
    • Prostate cancer (PCa) is the most common non-cutaneous malignancy in men and the leading cause of cancer-related deaths in Sweden. Despite the major advances, the current diagnostic modalities fall short of standards, specifically, precise localization required for effective management of the PCa. positron emission tomography (PET) combined with computed tomography (CT) has evolved as a promising diagnostic imaging technique for PCa. The progression of the PCa is often associated with metabolic alterations and overexpression of several proteins. Increased de novo fatty acid synthesis and prostate-specific membrane antigen (PSMA) overexpression are some of the distinctive features linked with PCa growth and the potential targets for the development of PET radiotracers.       This thesis is based on four original articles and focuses on the utilization of some of several different PET tracers available to visualize PCa spread. The work can be divided into two distinctive parts: (1) evaluate the prognostic value of 11C-acetate PET/CT towards survival in the setting of biochemical relapse after surgery, investigate tumour biology using single-tissue compartment model derived parametric images of 11C-acetate dynamic PET/CT both at patient and cell level and (2) the comparison of 68Ga-PSMA-11 PET/CT with 11C-acetate PET/CT and 18F-NaF PET/CT in patients with PCa relapse depicting different aspects of PCa biology.We demonstrated that quantification of 11C-acetate accumulation in PCa lesions was a strong predictor of survival in patients with biochemical relapse. Furthermore, parametric images of 11C-acetate dynamic PET/CT enabled visualization of tumour biology exhibiting elevated extraction of 11C-acetate associated with cancer aggressiveness also confirmed in in-vitro studies. 68Ga-PSMA-11 PET/CT located more widespread disease and performed significantly better in locating lymph node and bone metastases compared to 11C-acetate PET/CT. Similarly, 68Ga-PSMA-11 PET/CT was able to detect most of the bone lesions detected with 18F-NaF PET/CT along with additional soft tissue lesions.In conclusion, we showed the role of 11C-acetate PET/CT in PCa prognosis with additional understanding of tumour biology. Further, we successfully showed better performance of 68Ga-PSMA-11 PET/CT in locating PCa relapse and established it as a promising option for PCa re-staging.
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50.
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