| 1. |
- Javed, M. Tariq, et al.
(författare)
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Cadmium spiked soil modulates root organic acids exudation and ionic contents of two differentially Cd tolerant maize (Zea mays L.) cultivars
- 2017
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Ingår i: Ecotoxicology and Environmental Safety. - : Elsevier BV. - 0147-6513 .- 1090-2414. ; 141, s. 216-225
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Tidskriftsartikel (refereegranskat)abstract
- Our earlier work described that the roots of two maize cultivars, grown hydroponically, differentially responded to cadmium (Cd) stress by initiating changes in medium pH depending on their Cd tolerance. The current study investigated the root exudation, elemental contents and antioxidant behavior of the same maize cultivars (cv. 3062 (Cd-tolerant) and cv. 31P41 (Cd-sensitive)] under Cd stress. Plants were maintained in a rhizobox-like system carrying soil spiked with Cd concentrations of 0, 10, 20, 30, 40 and 50 mu mol/kg soil. The root and shoot Cd contents increased, while Mg, Ca and Fe contents mainly decreased at higher Cd levels, and preferentially in the sensitive cultivar. Interestingly, the K contents increased in roots of cv. 3062 at low Cd treatments. The Cd stress caused acidosis of the maize root exudates predominantly in cv. 3062. The concentration of various organic acids was significantly increased in the root exudates of cv. 3062 with applied Cd levels. This effect was diminished in cv. 31P41 at higher Cd levels. Cd exposure increased the relative membrane permeability, anthocyanin (only in cv. 3062), proline contents and the activities of peroxidases (POD) and superoxide dismutase (SOD). The only exception was the catalase activity, which was diminished in both cultivars. Root Cd contents were positively correlated with the secretion of acetic acid, oxalic acid, glutamic acid, citric acid, and succinic acid. The antioxidants like POD and SOD exhibited a positive correlation with the organic acids under Cd stress. It is likly that a high exudation of dicarboxylic organic acids improves nutrient uptake and activities of antioxidants, which enables the tolerant cultivar to acclimatize in Cd polluted environment.
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| 2. |
- Raza, Rizwan, et al.
(författare)
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Ce-0.8(SmZr)(0.2)O-2-carbonate nanocomposite electrolyte for solid oxide fuel cell
- 2014
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Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 38:4, s. 524-529
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Tidskriftsartikel (refereegranskat)abstract
- A nanocomposite Zr/Sm-codoped ceria electrolyte coated with K2CO3/Na2CO3 was synthesized by a coprecipitation method. The electrochemical study of the two-phase nanocomposite electrolytes with carbonate coated on the doped ceria shows high oxygen ion mobility at low temperatures (300-600 degrees C). The interface between the two constituent phases was studied by electrochemical impedance spectroscopy. Ionic conductivities were also measured with electrochemical impedance spectroscopy. The morphology and structure of composite electrolyte were characterized using field-emission scanning electron microscopy and X-ray diffraction. The fuel cell power density is 700 mW cm(-2), and an open-circuit voltage of 1.00 V is achieved at low temperatures (400-550 degrees C). This codoped approach with a second phase provides a good indication regarding overcoming the challenges of solid oxide fuel cell technology.
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| 3. |
- Tanwir, Kashif, et al.
(författare)
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Cadmium-induced rhizospheric pH dynamics modulated nutrient acquisition and physiological attributes of maize (Zea mays L.)
- 2015
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 22:12, s. 9193-9203
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Tidskriftsartikel (refereegranskat)abstract
- Cadmium (Cd) is a highly mobile toxic element in soil-plant systems that interferes with plant growth and nutrient acquisition by modulations in the rhizospheric environment. The current study investigated the influence of maize roots on the medium pH, alterations in nutrient uptake, and impact on the plant's physiological attributes under Cd stress. Among the nine maize cultivars, subjected to Cd stress (9.15 mg/kg of sand), one was identified as Cd tolerant (3062-Pioneer) and the second as Cd sensitive (31P41-Pioneer). The selected maize cultivars were grown in nutrient solutions supplemented with 0, 10, 20, 30, 40, or 50 mu M CdCl2 under controlled conditions and a starting pH of 6.0. The rhizospheric pH dynamics were monitored each day up to 3 days. Both cultivars caused medium basification; however, the response was different at low (10 and 20 mu M) Cd treatments (sensitive cultivar caused medium basification) and at higher (50 mu M) Cd treatment (tolerant cultivar caused medium basification). Furthermore, higher Cd was accumulated by the sensitive cultivar which was predominantly found in the roots. Higher Cd levels in the medium resulted in increased uptake and translocation of both Cd and K (in the tolerant cultivar) or only Cd (in the sensitive cultivar). Uptake of other nutrients (Ca, Zn, and Fe) was antagonistically affected by Cd stress in both cultivars. Moreover, Cd stress significantly impaired chlorophyll content, catalase activity, and total protein content; irrespective of the genotype. The malondialdehyde (MDA) content was found to increase, in both cultivars, together with Cd level. However, the extent to which Cd interfered with the studied attributes was more pronounced in the sensitive cultivar as compared to the tolerant one. It is concluded that the maize roots responded to Cd stress by initiating modulations of medium pH which might be dependent on Cd tolerance levels. The study results may help to develop strategies to reduce Cd accumulation in maize and decontamination of metal-polluted soil sediments.
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| 4. |
- Ahmed, A., et al.
(författare)
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Highly efficient composite electrolyte for natural gas fed fuel cell
- 2016
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 41:16, s. 6972-6979
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Tidskriftsartikel (refereegranskat)abstract
- Solid oxide fuel cells (SOFCs) have the ability to operate with different variants of hydro carbon fuel such as biogas, natural gas, methane, ethane, syngas, methanol, ethanol, hydrogen and any other hydrogen rich gas. Utilization of these fuels in SOFC, especially the natural gas, would significantly reduce operating cost and would enhance the viability for commercialization of FC technology. In this paper, the performance of two indigenously manufactured nanocomposite electrolytes; barium and samarium doped ceria (BSDC-carbonate); and lanthanum and samarium doped ceria (co-precipitation method LSDC-carbonate) using natural gas as fuel is discussed. The nanocomposite electrolytes were synthesized using co-precipitation and wet chemical methods (here after referred to as nano electrolytes). The structure and morphology of the nano electrolytes were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The fuel cell performance (OCV) was tested at temperature (300-600 °C). The ionic conductivity of the nano electrolytes were measured by two probe DC method. The detailed composition analysis of nano electrolytes was performed with the help of Raman Spectroscopy. Electrochemical study has shown an ionic conductivity of 0.16 Scm-1 at 600 °C for BSDC-carbonate in hydrogen atmosphere, which is higher than conventional electrolytes SDC and GDC under same conditions. In this article reasonably good ionic conductivity of BSDC-carbonate, at 600 °C, has also been achieved in air atmosphere which is comparatively greater than the conventional SDC and GDC electrolytes.
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| 5. |
- Axfors, Cathrine, et al.
(författare)
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Mortality outcomes with hydroxychloroquine and chloroquine in COVID-19 from an international collaborative meta-analysis of randomized trials
- 2021
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Substantial COVID-19 research investment has been allocated to randomized clinical trials (RCTs) on hydroxychloroquine/chloroquine, which currently face recruitment challenges or early discontinuation. We aim to estimate the effects of hydroxychloroquine and chloroquine on survival in COVID-19 from all currently available RCT evidence, published and unpublished. We present a rapid meta-analysis of ongoing, completed, or discontinued RCTs on hydroxychloroquine or chloroquine treatment for any COVID-19 patients (protocol: https://osf.io/QESV4/). We systematically identified unpublished RCTs (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, Cochrane COVID-registry up to June 11, 2020), and published RCTs (PubMed, medRxiv and bioRxiv up to October 16, 2020). All-cause mortality has been extracted (publications/preprints) or requested from investigators and combined in random-effects meta-analyses, calculating odds ratios (ORs) with 95% confidence intervals (CIs), separately for hydroxychloroquine and chloroquine. Prespecified subgroup analyses include patient setting, diagnostic confirmation, control type, and publication status. Sixty-three trials were potentially eligible. We included 14 unpublished trials (1308 patients) and 14 publications/preprints (9011 patients). Results for hydroxychloroquine are dominated by RECOVERY and WHO SOLIDARITY, two highly pragmatic trials, which employed relatively high doses and included 4716 and 1853 patients, respectively (67% of the total sample size). The combined OR on all-cause mortality for hydroxychloroquine is 1.11 (95% CI: 1.02, 1.20; I-2=0%; 26 trials; 10,012 patients) and for chloroquine 1.77 (95%CI: 0.15, 21.13, I-2=0%; 4 trials; 307 patients). We identified no subgroup effects. We found that treatment with hydroxychloroquine is associated with increased mortality in COVID-19 patients, and there is no benefit of chloroquine. Findings have unclear generalizability to outpatients, children, pregnant women, and people with comorbidities. Hydroxychloroquine and chloroquine have been investigated as a potential treatment for Covid-19 in several clinical trials. Here the authors report a meta-analysis of published and unpublished trials, and show that treatment with hydroxychloroquine for patients with Covid-19 was associated with increased mortality, and there was no benefit from chloroquine.
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| 6. |
- Javed, Nimra, et al.
(författare)
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Directly Printable Moisture Sensor Tag for Intelligent Packaging
- 2016
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Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 16:16, s. 6147-6148
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Tidskriftsartikel (refereegranskat)abstract
- A compact, flexible 24-b dual-polarized chip-less radio frequency identification tag with a size of 20.6mm x 19.9mm is realized. The tag structure is optimized and analyzed for Taconic, Kapton HN and organic substrate. The prototype fabricated on HP photopaper with silver nanoparticles-based conductive ink is exhibiting a behavior of moisture sensor. The proposed moisture sensor tag has a bandwidth of 13.5GHz. The direct printability of moisture sensor tag makes it suitable for intelligent packaging and various low-cost applications.
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| 7. |
- Raza, Rizwan, et al.
(författare)
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Composite electrolyte with proton conductivity for low-temperature solid oxide fuel cell
- 2015
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 107:18
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, cost-effective nanocomposite electrolyte (Ba-SDC) oxide is developed for efficient low-temperature solid oxide fuel cells (LTSOFCs). Analysis has shown that dual phase conduction of O-2 (oxygen ions) and H+ (protons) plays a significant role in the development of advanced LTSOFCs. Comparatively high proton ion conductivity (0.19 s/cm) for LTSOFCs was achieved at low temperature (460°C). In this article, the ionic conduction behaviour of LTSOFCs is explained by carrying out electrochemical impedance spectroscopy measurements. Further, the phase and structure analysis are investigated by X-ray diffraction and scanning electron microscopy techniques. Finally, we achieved an ionic transport number of the composite electrolyte for LTSOFCs as high as 0.95 and energy and power density of 90% and 550 mW/cm2, respectively, after sintering the composite electrolyte at 800°C for 4 h, which is promising. Our current effort toward the development of an efficient, green, low-temperature solid oxide fuel cell with the incorporation of high proton conductivity composite electrolyte may open frontiers in the fields of energy and fuel cell technology.
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| 8. |
- Raza, Rizwan, et al.
(författare)
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Fuel cell technology for sustainable development in Pakistan - An over-view
- 2016
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 53, s. 450-461
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Tidskriftsartikel (refereegranskat)abstract
- Fuel cell technology holds the combination of benefits, which are barely offered by any other energy generating technology. Because the fuel used in this technology is found in abundance in nature and can also be renewed/sustained. Pakistan is blessed with renewable energy resources which are suitable for fuel cell technology. Therefore, fuel cell technology offers a great opportunity to meet the demand of energy and for the sustainable development of Pakistan. The energy research group at COMSATS Institute of Information Technology (CIIT), Lahore has made efforts to study the technical aspects of fuel cell technology and its commercial benefits. The research group is interested in finding ways and means of generating and storing the energy produced by using fuel cells. In this paper, the research activities on fuel cell technology in Pakistan have been reviewed and it is also discussed how this technology can resolve the current energy crises in Pakistan and can be the source of sustainable energy. It has been also reviewed that the country would greatly benefit from fuel cells and fuel cell hybrid system (environmental friendly technology), which could be the best solution for electricity production as well for automobile industry.
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| 9. |
- Shahid, M., et al.
(författare)
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Serratia sp. CP-13 augments the growth of cadmium (Cd)-stressed Linum usitatissimum L. by limited Cd uptake, enhanced nutrient acquisition and antioxidative potential
- 2019
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Ingår i: Journal of Applied Microbiology. - : Oxford University Press (OUP). - 1364-5072 .- 1365-2672. ; 126:6, s. 1708-1721
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Tidskriftsartikel (refereegranskat)abstract
- Aims: The current study was aimed to evaluate the beneficial effects and bioremediation potential of a Cd-tolerant bacterial strain, Serratia sp. CP-13, on the physiological and biochemical functions of Linum usitatissimum L., under Cd stress.Methods and Results: The bacterial strain was isolated from the wastewater collection point of Chakera, Faisalabad, Pakistan, as this place contains industrial wastewater of the Faisalabad region. The Serratia sp. CP-13, identified through 16S rRNA gene sequence analysis, exhibited a significant phyto-beneficial potential in terms of in vitro inorganic phosphate solubilization, indole-3-acetic acid production and 1-aminocyclopropane-1-carboxylic acid deaminase activity. Effects of Serratia sp. CP-13 inoculation on L. usitatissimum were evaluated by growing the plants in CdCl2 (0, 5 or 10 mg kg(-1) dry soil)-spiked soil. Without inoculation of Serratia sp. CP-13, Cd stress significantly reduced the plant biomass as well as the quantity of proteins and photosynthetic pigments due to enhanced H2O2, malondialdehyde (MDA) contents and impaired nutrient homeostasis. Subsequently, Serratia sp. CP-13 increased the plant fresh and dry biomass, plant antioxidation capacity, whereas it decreased the lipid peroxidation under Cd stress. In parallel, Serratia sp. inoculation assisted the Cd-stressed plants to maintain an optimum level of nutrients (K, Ca, P, Mg, Fe and Mn).Conclusions: The isolated bacterial strain (Serratia sp. CP-13) when applied to Cd-stressed L. usitatissimum inhibited the Cd uptake, reduced Cd-induced lipid peroxidation, maintained the optimum level of nutrients and thereby, enhanced L. usitatissimum growth. The analysis of bio-concentration and translocation factor revealed that L. usitatissimum with Serratia sp. CP-13 inoculation sequestered Cd in plant rhizospheric zone.Significance and Impact of the Study: Serratia sp. CP-13 inoculation is a potential candidate for the development of low Cd-accumulating linseed and could be used for phytostabilization of Cd-contaminated rhizosphere/soil colloids.
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