161 research outputs found

    AC ELECTRIC TRANSPORT PROPERTIES OF Zn SUBSTITUTED Li FERRITES

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    The electrical transport properties of ZnxLi0.45-x/2Fe2.55-x/2O4 (where, x=0.0, 0.3, 0.5) synthesized by conventional ceramic method have been investigated as a function of Zn content. The X-ray analysis confirms the formation of single phase cubic spinel structure. The ac resistivity and dielectric constant show opposite trend with increase in Zn content. The ac resistivity and dielectric constant of the samples are found to decreases with increase in frequency, exhibiting normal ferromagnetic behaviour. Dielectric constant of the samples decreases rapidly at lower frequencies and slower at higher frequencies which may be due to the Maxwell-Wagner interfacial polarization. The electrical properties can be explained on the basis of Fe2+/Fe3+ ionic concentration

    Surface modification of thin-film composite forward osmosis membranes with polyvinyl alcohol–graphene oxide composite hydrogels for antifouling properties

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    © 2020 Elsevier B.V. In this study, the polyamide (PA) layers of commercial thin-film composite (TFC) forward osmosis (FO) membranes were coated with glutaraldehyde cross-linked polyvinyl alcohol (PVA) hydrogel comprising of graphene oxide (GO) at various loadings to enhance their fouling resistance. The optimal GO concentration of 0.02 wt% in hydrogel solution was confirmed from the FO membrane performance, and its influence on membrane antifouling properties was studied. The properties of the modified membranes, such as surface morphology, surface charge and wettability, were also investigated. PVA/GO coating was observed to increase the smoothness and hydrophilicity of the membrane surface. The foulant resistances of the pristine, PVA-coated and PVA/GO-coated membranes were also reported. PVA hydrogel-coated TFC membrane with a GO loading of 0.02 wt% showed a 55% reduction in specific reverse solute flux, only a marginal reduction in the water flux, and the best antifouling property with a 58% higher flux recovery than the pristine TFC membrane. The significant improvement in the selectivity of the modified membranes meant that the hydrogel coating could be used to seal PA defects. The biocidal GO flakes in PVA hydrogel coating also improved the biofouling resistance of the modified membranes, which could be attributed to their morphologies and superior surface properties

    Naupliar and Metanaupliar development of Thysanoessa raschii (Malacostraca, Euphausiacea) from Godthåbsfjord, Greenland, with a reinstatement of the ancestral status of the free-living Nauplius in Malacostracan evolution

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    The presence of a characteristic crustacean larval type, the nauplius, in many crustacean taxa has often been considered one of the few uniting characters of the Crustacea. Within Malacostraca, the largest crustacean group, nauplii are only present in two taxa, Euphauciacea (krill) and Decapoda Dendrobranchiata. The presence of nauplii in these two taxa has traditionally been considered a retained primitive characteristic, but free-living nauplii have also been suggested to have reappeared a couple of times from direct developing ancestors during malacostracan evolution. Based on a re-study of Thysanoessa raschii (Euphausiacea) using preserved material collected in Greenland, we readdress this important controversy in crustacean evolution, and, in the process, redescribe the naupliar and metanaupliar development of T. raschii. In contrast to most previous studies of euphausiid development, we recognize three (not two) naupliar (= ortho-naupliar) stages (N1-N3) followed by a metanauplius (MN). While there are many morphological changes between nauplius 1 and 2 (e.g., appearance of long caudal setae), the changes between nauplius 2 and 3 are few but distinct. They involve the size of some caudal spines (largest in N3) and the setation of the antennal endopod (an extra seta in N3). A wider comparison between free-living nauplii of both Malacostraca and non-Malacostraca revealed similarities between nauplii in many taxa both at the general level (e.g., the gradual development and number of appendages) and at the more detailed level (e.g., unclear segmentation of naupliar appendages, caudal setation, presence of frontal filaments). We recognize these similarities as homologies and therefore suggest that free-living nauplii were part of the ancestral malacostracan type of development. The derived morphology (e.g., lack of feeding structures, no fully formed gut, high content of yolk) of both euphausiid and dendrobranchiate nauplii is evidently related to their non-feeding (lecithotrophic) status

    Assessment of serum IgE level in patients with transfusion related allergic reaction receiving fresh frozen plasma

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    Background: Blood transfusion is a routine lifesaving medical intervention which is generally regarded as safe when done properly. However, at the same time it also bears considerable risk. The aim of the study was to assess the serum IgE levels in patients experiencing transfusion-related allergic reactions after receiving fresh frozen plasma. Methods: This cross-sectional observational study was conducted at the Department of Transfusion Medicine, BSMMU, from March 2019 to August 2021, focusing on patients aged 5 to 60 years receiving fresh frozen plasma. Patients were included after obtaining informed consent from themselves or their legal guardians in the case of minors, according to the eligibility criteria. Data were analyzed using SPSS version 26, with statistical significance set at p<0.05, employing Chi-square tests and Pearson’s correlation coefficient for variable comparisons. Results: Raised IgE level was significantly related with transfusion related allergic reaction after receiving fresh frozen plasma (p<0.05). The mean IgE was 521.4±434.6 in patients with reaction and 67.8±33.2 in patients without reaction. Significant positive correlation was observed in serum IgE level with age in years. Conclusions: Patients with transfusion related allergic reaction receiving fresh frozen plasma had higher mean IgE levels as compared to those without reaction

    On the valence shell spectroscopy of 1,2-dichlorobenzene

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    Funding Information: MHFB acknowledges the Brazilian agency Coordenaç˜ ao de Aperfei çoamento de Pessoal de Nível Superior (CAPES) and together with LVSD and ASB the support from the Brazilian agency Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). LVSD, ASB and MHFB also acknowledge Prof. Carlos A. M. de Carvalho for computational support at LFTC-DFis-UFPR and at LCPAD-UFPR. The authors wish to acknowledge the beam time at the ISA synchrotron, Aarhus University, Denmark. The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. PLV acknowledges the Portuguese National Funding Agency (FCT) through research grant CEFITEC (UIDB/00068/2020), his visiting professor position at Federal University of Paraná, Curitiba, Brazil and the support from CAPES PrInt/UFPR. This work was also supported by Radiation Biology and Biophysics Doctoral Training Programme (RaBBiT, PD/00193/2012) and UCIBIO (UIDB/04378/2020).We report high-resolution vacuum ultraviolet (VUV) photoabsorption spectrum of 1,2-dichlorobenzene in the photon energy range 4.0–10.8 eV (310–115 nm). The electronic state spectroscopy of ortho-C6H4Cl2 has been investigated together with quantum chemical calculations at different levels of theory, also providing vertical excitation energies and oscillator strengths. The valence, mixed valence-Rydberg and Rydberg character of the electronic transitions is accompanied by fine structure which has been mainly assigned to in-plane breathing with C–Cl stretching, v7′a1, ring breathing and C–C stretching, v8′a1, in-plane ring breathing, v9′a1, C–Cl symmetric stretching, v10′a1, and in-plane C–Cl bending v11′a1 modes. The experimental absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of 1,2-dichlorobenzene in the Earth's atmosphere (0–50 km), showing that solar photolysis is expected to be a weak sink at altitudes lower than 20 km relative to [rad]OH radical reactions. Potential energy curves for the lowest-lying excited electronic states, as a function of the C–Cl stretching and in-plane C–Cl bending coordinates, were also obtained employing the time dependent density functional theory (TD-DFT) method. The results show the importance of the complex quasi-degenerate nature of the lowest-lying electronic states which in the intricate nuclear dynamics of the reaction coordinates, yield relevant internal conversion from Rydberg to valence character and in the asymptotic limit bond excision.publishersversionpublishe

    Advances in understanding physical and biological controls on eggs and larval distribution in Pacific fisheries: A review

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    The early stages of fish, comprising eggs and larvae, are exceptionally fragile and sensitive to environmental dynamics and climate change. Pacific Ocean (PO) currents play an important role in shaping the distribution of marine organisms, influencing global climate patterns, heat distribution, coastal temperatures, and nutrient redistribution. These currents reveal significant changes within the climate system. Their variability across different timescales can be attributed to the complex interplay of physical forces. These currents are subjected to diverse anthropogenic factors, exerting detrimental effects on the dispersal of fish larvae. Furthermore, climate change variables, including alterations in tropical PO temperature associated with the ENSO cycle, Atlantic Nino modes influencing equatorial Atlantic temperature, changes in ocean salinity, polar ice cap melting, increasing greenhouse gases, marine heatwaves, and fluctuations in subsurface flows, directly impact the distribution, abundance, and species composition of early life stages. Major Pacific fisheries, such as those targeting Pacific sardines, saury, and anchovies, undergo population booms and declines due to significant alterations in the current dynamics of currents and fronts within the PO. The anticipated intensification of the ENSO cycle, characterized by more frequent and severe El Niño (warm) and La Niña (cold) events as a result of climate change, is expected to significantly impact the early developmental stages of important commercial fish stocks regularly. This review synthesizes the current understanding of the physical and biological parameters driving changes in ocean currents and their implications for early fish dispersion, emphasizing the critical need for research in this area to inform global conservation efforts, fisheries management, and food security

    Post-COVID-19 complications in home and hospital-based care: A study from Dhaka city, Bangladesh

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    A cross-sectional survey was undertaken to understand the management patterns and post-COVID-19 complications among hospital and home-treated participants. Retrospective information was collected from four COVID-19 dedicated hospitals and four selected community settings. Using probability proportional sampling, 925 participants were selected. Data were collected using a semi-structured questionnaire. Bivariate and multivariate logistic regression analysis and the exact chi-square tests were utilized to analyze the association between the studied variables. A total of 659 participants responded (response rate 70.93%); 375 from hospitals and 284 from communities. About 80% of participants were mild cases, 75% were treated at home, and 65% of hospital-treated participants were referred after home treatment. Participants treated at home-to hospital and directly in the hospital had 1.64 and 3.38 times longer recovery time respectively than what home-based participants had. A significant increasing trend (p < 0.001) of co-morbidities was found among referred and hospital treated participants. Age, level of education, physical exercise, practicing preventive measures, exposure to sunlight, and intake of carbohydrate, additional liquid, food supplements, and avoidance of junk foods were significantly associated with place of treatment. Post-COVID-19 difficulties of all factors were statistically significant for home treatment participants, whilst only depression (p = 0.026), chest pain (p = 0.017), and digestive disorders (p = 0.047) were significant (p < 0.05) for hospital treated participants. The outcomes from this study provide insight into a range of post-COVID-19 difficulties relating to at home and in hospital treatment participants. There are clear differences in the complications experienced, many of which are statistically significant. The health care professionals, the community people and COVID-19 survivors will be benefitted from the study findings, and the policy level people may use the information for designing health education program on post COVID-19 complications
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