| 1. |
- Khan, Kifayatullah, et al.
(författare)
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Heavy Metal Occurrence, Pathways, and Associated Socio-ecological Risks in Riverine Water : Application of Geographic Information System, Multivariate Statistics, and Risk Assessment Models
- 2023
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Ingår i: Water, Air and Soil Pollution. - 0049-6979 .- 1573-2932. ; 234:7
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Tidskriftsartikel (refereegranskat)abstract
- Heavy metal (HM) pollution is one of the major issues of concern in the world due to its serious health consequences on humans and ecology. In this study, riverine water from the River Kabul in Pakistan was studied using inductively coupled plasma mass spectrometry (ICP-MS) to determine the variation, routes, and possible socio-ecological hazards of chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn) cadmium (Cd), mercury (Hg), and lead (Pb). The results revealed significant HMs variation (p < 0.05) in the sequence of Cr > Zn > Ni > Cu > Cd > Pb > Mn > Co > Hg, indicating prevalent metal contaminations in the river. Multivariate statistics showed significant strong positive correlations (p ≤ 0.01) between the individual HMs contents along the monitoring sites. The strong-moderate levels of Cu, Co, Zn, Mn, Pb, and Cd in riverine systems were observed to be caused by surrounding industrial, agrochemicals, mining, and domestic wastewater discharges along with geogenic sources, the weak levels of Cr and Ni could be induced by erosion of mafic and ultramafic rocks, and mining activities, whereas the low contamination of Hg suggests minimal atmospheric deposition with fewer industrial discharges in the environment. The overall mass flux of the ∑HMs was estimated to be around 164.10 kg/year, with significant HM pollution index (HPI) and pollution index (PI) variations along the river characterizing the potential risk of HMs in decreasing order of Cd > Hg > Cr > Ni > Co > Pb > Mn > Cu > Zn and Cd > Hg > Ni > Pb > Cr > Co > Cu > Mn > Zn, respectively. Individual HM contamination was within the ecological risk threshold (ERI < 110), where, the chronic daily intake (CDIs), hazard quotients (HQs), health indices (HIs), and cancer risks (CRs) of Cd, Ni, Co, Cr, and Pb by daily riverine water ingestion and dermal contact posing considerable human health concerns. To protect the environment and public health, our findings suggest that untreated anthropogenic wastewater discharge into the river system be strictly controlled and regulated through public awareness campaigns and legislation prohibiting the use of herbicides and fertilizers containing high levels of Cr, Ni, Co, Cd, and Pb.
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| 2. |
- Khan, Kifayatullah, et al.
(författare)
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Heavy metals in five commonly consumed fish species from River Swat, Pakistan, and their implications for human health using multiple risk assessment approaches
- 2023
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Ingår i: Marine Pollution Bulletin. - 0025-326X .- 1879-3363. ; 195
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Tidskriftsartikel (refereegranskat)abstract
- This study analyzed the levels of heavy metals bioaccumulation in commonly consumed riverine fish species, including G. cavia, T. macrolepis, G. gotyla, S. plagiostomus, and M. armatus from River Swat in Pakistan, and quantify their potential risk to children and adults in general and fisherfolk communities using multiple pollution and risk assessment approaches. The highest metal detected by inductive coupled plasma mass spectrometry (ICP-MS) was Zn, which ranged from 49.61 to 116.83 mg/kg, followed by Fe (19.25–101.33 mg/kg) > Mn (5.25–40.35 mg/kg) > Cr (3.05–14.59 mg/kg) > Ni (4.26–11.80 mg/kg) > Al (1.59–12.25 mg/kg) > Cu (1.24–8.59 mg/kg) > Pb (0.29–1.95 mg/kg) > Co (0.08–0.46 mg/kg) > Cd (0.01–0.29 mg/kg), demonstrating consistent fluctuation with the safe recommendations of global regulatory bodies. The average bioaccumulation factor (BAF) values in the examined fish species were high (BAF > 5000) for Pb, Zn, Mn, Cu, Cr, Ni, and Cd, bioaccumulate (1000 > BAF < 5000) for Co, and probable accumulative (BAF <1000) for Fe, and Al, while the overall ∑heavy metals pollution index (MPI) values were greater than one (MPI > 1) indicating sever heavy metals toxicity in G. cavia, followed by S. plagiostomus, M. armatus, G. gotyla, and T. macrolepis. The multivariate Pearson's correlation analysis identified the correlation coefficients between heavy metal pairs (Ni Cr, Cu Cr, Pb Cr, Al Co, Cu Ni, and Pb Ni), the hierarchical cluster analysis (CA) determined the origin by categorizing heavy metal accumulation into Cluster-A, Cluster-B, and Cluster-C, and the principal component analysis (PCA) discerned nearby weathering, mining, industrial, municipal, and agricultural activities as the potential sources of heavy metals bioaccumulation in riverine fish. As per human risk perspective, S. plagiostomus contributed significantly to the estimated daily intake (EDI) of heavy metals, followed by G.cavia > M. armatus > G. gotyla > T. macrolepis in dependent children and adults of the fisherfolk followed by the general population. The non-carcinogenic target hazard quotient (THQ) and hazard index (HI) values for heavy metal intake through fish exposure were < 1, while the carcinogenic risk (CR) for individual metal intake and the total carcinogenic risk (TCR) for cumulative Cr, Cd, and Pb intake were within the risk threshold of 10−6–10−4, suggesting an acceptable to high non-carcinogenic and carcinogenic risk for both children and adults in the fisherfolk, followed by the general population.
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| 3. |
- Hussain, Muhammad Mahroz, et al.
(författare)
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Arsenic biogeochemical cycling in paddy soil-rice system : Interaction with various factors, amendments and mineral nutrients
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 773
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Tidskriftsartikel (refereegranskat)abstract
- Arsenic (As) contamination is a well-recognized environmental and health issue, threatening over 200 million people worldwide with the prime cases in South and Southeast Asian and Latin American countries. Rice is mostly cultivated under flooded paddy soil conditions, where As speciation and accumulation by rice plants is controlled by various geo-environmental (biotic and abiotic) factors. In contrast to other food crops, As uptake in rice has been found to be substantially higher due to the prevalence of highly mobile and toxic As species, arsenile (As(Ill)), under paddy soil conditions. In this review, we discussed the biogeochemical cycling of As in paddy soil-rice system, described the influence of critical factors such as pH, iron oxides, organic matter, microbial species, and pathways affecting As transformation and accumulation by rice. Moreover, we elucidated As interaction with organic and inorganic amendments and mineral nutrients. The review also elaborates on As (im) mobilization processes and As uptake by rice under the influence of different mineral nutrients and amendments in paddy soil conditions, as well as their role in mitigating As transfer to rice grain. This review article provides critical information on As contamination in paddy soil-rice system, which is important to develop suitable strategies and mitigation programs for limiting As exposure via rice crop, and meet the UN's key Sustainable Development Goals (SDGs: 2 (zero hunger), 3 (good health and well-being), 12 (responsible consumption and production), and 13 (climate action)).
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| 4. |
- Muhammad, Noor, et al.
(författare)
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Novel mutations in MPT64 secretory protein of Mycobacterium tuberculosis complex
- 2023
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 20:3
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Tidskriftsartikel (refereegranskat)abstract
- Tuberculosis (TB) is a global health problem caused by the Mycobacterium tuberculosis complex (MTBC). These bacteria secrete various proteins involved in the pathogenesis and persistence of MTBC. Among the secretory proteins, MPT64 (Rv1980C) is highly conserved and is also known as a major culture filtrate that is used in rapid diagnosis of MTBC. In the current study, we aimed to find the mutation in this highly conserved protein in isolates from the Pashtun-dominant province of Pakistan. We analyzed 470 M. tuberculosis whole-genome sequences of Khyber Pakhtunkhwa Province. Mutations in the MPT64 gene were screened through TB-Profiler and BioEdit software tools. The DynaMut web server was used to analyze the impact of the mutation on protein dynamics and stability. Among 470 MTB genomes, three non-synonymous mutations were detected in nine isolates, and one synonymous mutation (G208A) was found in four isolates. Mutation G211T (F159L), which was detected at the C-terminal domain of the protein in six isolates, was the most prominent. The second novel mutation, T480C (I70V), was detected in two isolates at the C-terminal side of the protein structure. The third novel mutation, A491C (L66R), was detected in a single isolate at the N-terminal side of the MPT64 protein. The effect of these three mutations was destabilizing on the protein structure. The molecular flexibility of the first two mutations increased, and the last one decreased. MPT64 is a highly conserved secretory protein, harboring only a few mutations. This study provides useful information for better managing the diagnosis of MTB isolates in high TB-burden countries.
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| 5. |
- Riaz, Muhammad, et al.
(författare)
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Evaluation of clinical and laboratory characteristics of dengue viral infection and risk factors of dengue hemorrhagic fever : a multi-center retrospective analysis
- 2024
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Ingår i: BMC Infectious Diseases. - : BioMed Central (BMC). - 1471-2334. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundDengue Viral Infection (DVI) has become endemic in Pakistan since the first major outbreak in Karachi in 1996. Despite aggressive measures taken by relevant authorities, Pakistan has been dealing with a worsening dengue crisis for the past two decades. DHF is severe form of dengue infection which is linked with significant morbidity and mortality. Early identification of severe dengue infections can reduce the morbidity and mortality. In this context we planned current study in which we find out the different factors related with DHF as well as clinical laboratory features of DHF and compare them to DF so that patients can be best evaluated for DHF and managed accordingly at admission.MethodsRetrospective study conducted over a period of 6 years (2013-2018) in two tertiary care hospitals in Pakistan. Data were collected by using a pre-structured data collection form. Data were statistically analyzed to determine the clinical and laboratory characteristics of DVI and risk factors of dengue hemorrhagic fever (DHF).ResultsA total 512 dengue cases (34.05 +/- 15.08 years; Male 69.53%) were reviewed. Most common clinical manifestations of DVI were fever (99.60%), headache (89.1%), chills (86.5%), rigors (86.5%), myalgia (72.3%). Less common clinical manifestations were vomiting (52.5%), arthralgia (50.2%) and skin rashes (47.5%). Furthermore, nasal bleeding (44.1%), gum bleeding (32.6%), pleural effusion (13.9%) and hematuria (13.1%) were more profound clinical presentations among DHF patients. Mortality rate was 1.5% in this study. Logistic regression analysis indicated that delayed hospitalization (OR: 2.30) and diabetes mellitus (OR:2.71), shortness of breath (OR:2.21), association with risk groups i.e., living near stagnant water, travelling to endemic areas, living in endemic regions (OR:1.95), and presence of warning signs (OR:2.18) were identified as risk factors of DHF. Statistically we found that there is strong association of diabetes mellitus (DM) with DHF while the patient suffering from DM individually had higher odds (2.71) of developing DHF than patients without disease.ConclusionsThe current study demonstrated that the clinical and laboratory profiles of DF and DHF are significantly distinct. Significant predictors of DHF were advanced age, diabetes mellitus, ascites, pleural effusion, thick gallbladder and delayed hospitalization. The identification of these factors at early stage provides opportunities for the clinicians to identify high risk patients and to reduce dengue-related morbidity and mortality.
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| 6. |
- Naqvi, Salman Raza, et al.
(författare)
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New trends in improving gasoline quality and octane through naphtha isomerization : a short review
- 2018
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Ingår i: APPLIED PETROCHEMICAL RESEARCH. - : Springer. - 2190-5533 .- 2190-5533 .- 2190-5525. ; 8:3, s. 131-139
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Forskningsöversikt (refereegranskat)abstract
- The octane enhancement of light straight run naphtha is one of the significant solid acid catalyzed processes in the modern oil refineries due to limitations of benzene, aromatics, and olefin content in gasoline. This paper aims to examine the role of various catalysts that are being utilized for the isomerization of light naphtha with an ambition to give an insight into the reaction mechanism at the active catalyst sites, and the effect of various contaminants on catalyst activity. In addition, different technologies used for isomerization process are evaluated and compared by different process parameters.
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| 7. |
- Yameen, Muhammad Zubair, et al.
(författare)
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Biodiesel production from marine macroalgae Ulva lactuca lipids using novel Cu-BTC@AC catalyst : Parametric analysis and optimization
- 2024
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Ingår i: Energy Conversion and Management. - : Elsevier. - 2590-1745. ; 23
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Tidskriftsartikel (refereegranskat)abstract
- The pursuit of renewable fuels for the transportation sector, particularly for combustion engines like diesel, is crucial in reducing greenhouse gas emissions. This study introduces an innovative strategy for biodiesel production utilizing marine macroalgae Ulva lactuca as the primary feedstock, emphasizing sustainability and resource efficiency. Lipids were extracted from the macroalgae via a Soxhlet process and characterized using GC–MS and FTIR to ascertain fatty acid composition and functional groups. The Cu–BTC@AC catalyst, synthesized from the lipid-extracted algae residue via pyrolysis and hydrothermal treatment, underwent characterization using SEM–EDS, XRD, and FTIR techniques. Subsequently, the Cu–BTC@AC catalyst was employed in the transesterification process to efficiently convert the extracted algal lipids into biodiesel, achieving a high yield of 92.56 % under RSM-optimized conditions: 65 °C temperature, 3.96 wt% catalyst amount, 15:1 methanol-to-lipid ratio, and 140 min reaction time. Kinetic and thermodynamic parameters for biodiesel production were calculated as follows: Ea = 33.20 kJ mol−1, ΔH# = 30.39 kJ mol−1, ΔS# = –165.86 J mol−1 K−1, and ΔG# = 86.48 kJ mol−1. GC–MS analysis identified a significant FAME content in the biodiesel, comprising 98.12 % of its composition. Notably, the Cu–BTC@AC catalyst exhibited excellent reusability, maintaining 80.21 % biodiesel yield after the third cycle. Moreover, physicochemical analysis of the biodiesel confirmed its compliance with ASTM D6751 specifications, underscoring its potential as a viable alternative fuel for the transportation sector.
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| 8. |
- Yaseen, Noor, et al.
(författare)
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Synergistic impacts of high-volume fly ash and sugarcane bagasse ash on performance of cementitious composites reinforced with polyvinyl alcohol fibers
- 2023
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Ingår i: Results in Materials. - : Elsevier. - 2590-048X. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- Disposal of waste materials in fertile land is one of the pressing environmental issues, disrupting human, animal, and plant life. This has led the researchers to process and use such waste in ecofriendly construction products like mortar and concrete. Their usage as supplementary cementitious materials (SCMs) would reduce the quantity of cement used in the manufacturing of cement-based materials, lowering CO2 emissions related with cement production. In this regard, this study examines the feasibility of replacing high-volume of ordinary Portland cement (OPC) in engineered cementitious composites (ECC) with two widely used waste materials, sugarcane bagasse ash (SCBA) and fly ash (FA) as SCMs. Five different mixes were produced, each containing a fixed amount of polyvinyl alcohol (PVA) fibers at a dosage of 1.5 % by volume of the mix and a constant cement content of 50 % by weight of the binder (OPC + FA + SCBA). However, FA was replaced with SCBA in these mixes up to 100 % by the combined weight of the waste materials (FA + SCBA) in increments of 25 % (i.e., FA100-SCBA0, FA75-SCBA25, FA50-SCBA50, FA25-SCBA75, and FA0-SCBA100). The results showed that the compressive strength and flexural strength of the composites with the increasing levels of SCBA were reduced. Interestingly, the 28-day compressive strength of composite incorporating 50 % FA and 50 % SCBA was still as high as 25.58 MPa, which satisfied the minimum compressive strength requirement of ASTM C270, making the newly produced ECC suitable for use in normal construction works and repairs. The same optimum mix (FA50-SCBA50) produced an average density of 1867.96 kg/m3 as a result of substituting a significant amount of binder with SCBA, demonstrating that it has evolved into a lightweight engineered cementitious composite. Furthermore, the ultrasonic pulse velocity of the mixes decreased whereas water absorption increased as the proportion of SCBA to FA increased. According to microstructural analysis, unreacted SCBA particles were mostly responsible for the detrimental effects of rising SCBA levels on properties of ECC. Based on the aforementioned results, this research concludes that sugarcane bagasse ash, when combined with fly ash, could be a viable alternative for replacing regular cement up to 50 % by weight in the production of cost-effective and environmentally friendly cementitious composites.
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| 9. |
- Yousaf, Muhammad, et al.
(författare)
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Electrochemical properties of Ni0.4Zn0.6 Fe2O4 and the heterostructure composites (Ni-Zn ferrite-SDC) for low temperature solid oxide fuel cell (LT-SOFC)
- 2020
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Ingår i: Electrochimica Acta. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0013-4686 .- 1873-3859. ; 331
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Tidskriftsartikel (refereegranskat)abstract
- In solid oxide fuel cell, the redox reactions (HOR and ORR) demand good catalyst functions at the anode and cathode. Triple phase boundary (TPB) is an important mechanism to determine HOR and ORR as key factors to improve the reaction rate, charge transfer and ion diffusion processes. In the present work, Ni0.4Zn0.6Fe2O4 (Ni-Zn ferrite) and its heterostructures with Sm0.2Ce0.8O2 (SDC) are prepared and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to analyze the phase structure and morphology of the material. X-ray photoelectron spectroscopy (XPS) confirms the phase of Ni-Zn ferrite nanoparticles (NPs) and chemical states on the heterostructure surface. The electrical and conductive behaviors of synthesized samples are investigated through electrochemical impedance spectroscopy (EIS) and fuel cell measurements. Unlike to conventional way, the as-prepared samples promote redox reactions from two aspects: a) as an electrolyte for ion transport; b) as a mixed conductor to extend the ionic transport on TPB region. The ionic transfer mechanism of Ni-Zn ferrite/SDC composite leads the improved fuel cell performance up to 760 mW/cm(2) at 550 degrees C. Further investigations verify the appreciable proton conduction in the prepared devices in a range of 0.012-0.048 Scm(-1).
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| 10. |
- Abbas, Syed Adeel, et al.
(författare)
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Spinel-type Na2MoO4 and Na2WO4 as promising optoelectronic materials : First-principle DFT calculations
- 2020
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Ingår i: Chemical Physics. - : Elsevier. - 0301-0104 .- 1873-4421. ; 538
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical, thermodynamic, electronic, and optical properties of Na2MoO4 (NMO) and Na2WO4 (NWO) spinels are elaborated by density functional theory (DFT) based full potential augmented plane wave method (FP-LAPW + lo). Our optimized lattice constants for the studied spinels are in good agreement with that obtained experimentally. The enthalpy of formation ensures the thermodynamic stability of NMO and NWO in the cubic phase. The Born mechanical stability criteria guarantees their mechanical stability, while Poisson ratio (ν) and Pugh's ratio (B/G) infer their brittle behavior. The Debye temperature (θD) is significant for NMO than NWO. The wide bandgap of 3.5 eV for NMO and 4.4 eV for NWO show the maximum absorption in the ultraviolet region that increases their importance for optoelectronic applications. The optical properties are explained in term of dielectric constant, refractive index, absorption of light, reflection, and optical loss factor.
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