26 research outputs found

    Conductivity study of Zeolitic Imidazolate Frameworks, Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks, and mixed matrix membranes of Polyetherimide/Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks for proton conducting applications

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    [EN] ZIF-8 (Z8), ZIF-67 (Z67), and ZMix, a Zn/Co bimetallic zeolitic imidazolate framework (ZIF), were synthesized and doped with tetrabutylammonium hydroxide (ZIFsT). The obtained powders were used as fillers for polyetherimide (PEI) at a concentration of 20 wt %. The presence of the three ZIFsT in the polymeric matrix enhanced proton transport relative to that observed for PEI or ZIFs alone. The real and imaginary parts of the complex conductivity were obtained for each of the six materials, and the temperature and frequency dependence of the real part was analyzed. The results at different temperatures show that the dc-conductivity are about three orders of magnitude higher for the doped ZIFsT materials than for the PEI/ZIFsT membranes. In addition, the conductivity of the PEI/ZIFsT membranes increases five or six times when the temperature is changed from 25 °C to 55 °C. For these materials, the conductivity measurements have a linear dependency with frequency, which allowed for the creation of a master curve. It was also found that the PEI/ZMixT membrane activation energy is four times smaller than that of PEI/Z8T membranes and five times smaller than that of PEI/Z67T. Similarly, the real and imaginary parts of the complex dielectric constant were obtained, and the tan ¿ was evaluated. Using this value, the diffusion coefficient and the charge carrier density were obtained. A discussion of the proton transport mechanism through the membrane is given, and a comparison of this work with those on similar electrolyte membranes is included.This research has been supported by the ENE/2015-69203-R project, granted by the Ministerio de Economia y Competitividad (MINECO), Spain, and grants from National Mexican Council for Science and Technology for the scholarships of Ph.D. No. 356825 and mixed scholarship 2015 - MZO2016-mobility in the foreigner granted to Jesus Vega Moreno registered scholarship holder number 256015. Thanks to the CONACYT Program for the fellowship at the Universidad Politecnica de Valencia (UPV) and Universitat Jaume I that PhD student Jesus Vega used to carry out the experimental studies of this work. DGAPA-PAPIIT IG-100315.Vega, J.; Andrio, A.; Lemus, AA.; Del Castillo, LF.; Compañ Moreno, V. (2017). Conductivity study of Zeolitic Imidazolate Frameworks, Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks, and mixed matrix membranes of Polyetherimide/Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks for proton conducting applications. Electrochimica Acta. 258:153-166. https://doi.org/10.1016/j.electacta.2017.10.095S15316625

    Spike protein mutations and structural insights of pangolin lineage B.1.1.25 with implications for viral pathogenicity and ACE2 binding affinity

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    Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID -19, is constantly evolving, requiring continuous genomic surveillance. In this study, we used whole-genome sequencing to investigate the genetic epidemiology of SARS-CoV-2 in Bangladesh, with particular emphasis on identifying dominant variants and associated mutations. We used high-throughput next-generation sequencing (NGS) to obtain DNA sequences from COVID-19 patient samples and compared these sequences to the Wuhan SARS-CoV-2 reference genome using the Global Initiative for Sharing All Influenza Data (GISAID). Our phylogenetic and mutational analyzes revealed that the majority (88%) of the samples belonged to the pangolin lineage B.1.1.25, whereas the remaining 11% were assigned to the parental lineage B.1.1. Two main mutations, D614G and P681R, were identified in the spike protein sequences of the samples. The D614G mutation, which is the most common, decreases S1 domain flexibility, whereas the P681R mutation may increase the severity of viral infections by increasing the binding affinity between the spike protein and the ACE2 receptor. We employed molecular modeling techniques, including protein modeling, molecular docking, and quantum mechanics/molecular mechanics (QM/MM) geometry optimization, to build and validate three-dimensional models of the S_D614G-ACE2 and S_P681R-ACE2 complexes from the predominant strains. The description of the binding mode and intermolecular contacts of the referenced systems suggests that the P681R mutation may be associated with increased viral pathogenicity in Bangladeshi patients due to enhanced electrostatic interactions between the mutant spike protein and the human ACE2 receptor, underscoring the importance of continuous genomic surveillance in the fight against COVID -19. Finally, the binding profile of the S_D614G-ACE2 and S_P681R-ACE2 complexes offer valuable insights to deeply understand the binding site characteristics that could help to develop antiviral therapeutics that inhibit protein–protein interactions between SARS-CoV-2 spike protein and human ACE2 receptor

    Human Health Risk Assessment For Arsenic: A Critical Review

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    Millions of people are exposed to arsenic resulting in a range of health implications.This paper provides an up-to-date review of the different sources of arsenic (water, soil and food), indicators of human exposure (biomarker assessment of hair, nail, urine and blood), epidemiological and toxicological studies on carcinogenic and non-carcinogenic health outcomes, and risk assessment approaches. The review demonstrates a need for more work evaluating the risks of different arsenic species such as; arsenate, arsenite monomethylarsonic acid, monomethylarsonous acid, dimethylarsinic acid and dimethylarsinous acid as well as a need to better integrate the different exposure sources in risk assessments

    Letter of interest for a neutrino beam from Protvino to KM3NeT/ORCA

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    The Protvino accelerator facility located in the Moscow region, Russia, is in a good position to offer a rich experimental research program in the field of neutrino physics. Of particular interest is the possibility to direct a neutrino beam from Protvino towards the KM3NeT/ORCA detector, which is currently under construction in the Mediterranean Sea 40 km offshore Toulon, France. This proposal is known as P2O. Thanks to its baseline of 2595 km, this experiment would yield an unparalleled sensitivity to matter effects in the Earth, allowing for the determination of the neutrino mass ordering with a high level of certainty after only a few years of running at a modest beam intensity of ≈ 90 kW. With a prolonged exposure (≈1500 kWyear), a 2σ sensitivity to the leptonic CP-violating Dirac phase can be achieved. A second stage of the experiment, comprising a further intensity upgrade of the accelerator complex and a densified version of the ORCA detector (Super-ORCA), would allow for up to a 6σ sensitivity to CP violation and a 10º−17º resolution on the CP phase after 10 years of running with a 450 kW beam, competitive with other planned experiments. The initial composition and energy spectrum of the neutrino beam would need to be monitored by a near detector, to be constructed several hundred meters downstream from the proton beam target. The same neutrino beam and near detector set-up would also allow for neutrino-nucleus cross section measurements to be performed. A short-baseline sterile neutrino search experiment would also be possible

    Multimessenger NuEM Alerts with AMON

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    The Astrophysical Multimessenger Observatory Network (AMON), has developed a real-time multi-messenger alert system. The system performs coincidence analyses of datasets from gamma-ray and neutrino detectors, making the Neutrino-Electromagnetic (NuEM) alert channel. For these analyses, AMON takes advantage of sub-threshold events, i.e., events that by themselves are not significant in the individual detectors. The main purpose of this channel is to search for gamma-ray counterparts of neutrino events. We will describe the different analyses that make-up this channel and present a selection of recent results

    The global burden of cancer attributable to risk factors, 2010–19: a systematic analysis for the Global Burden of Disease Study 2019

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    BACKGROUND: Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. METHODS: The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk–outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. FINDINGS: Globally, in 2019, the risk factors included in this analysis accounted for 4·45 million (95% uncertainty interval 4·01–4·94) deaths and 105 million (95·0–116) DALYs for both sexes combined, representing 44·4% (41·3–48·4) of all cancer deaths and 42·0% (39·1–45·6) of all DALYs. There were 2·88 million (2·60–3·18) risk-attributable cancer deaths in males (50·6% [47·8–54·1] of all male cancer deaths) and 1·58 million (1·36–1·84) risk-attributable cancer deaths in females (36·3% [32·5–41·3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20·4% (12·6–28·4) and DALYs by 16·8% (8·8–25·0), with the greatest percentage increase in metabolic risks (34·7% [27·9–42·8] and 33·3% [25·8–42·0]). INTERPRETATION: The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden

    Bioactive Compounds and Biochemical and Antioxidant Properties of Selected Minor Indigenous Fruits in Bangladesh

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    Minor fruits are a potential source of antinutrients, but there is no complete primary data source in the Bangladeshi context. Therefore, the present study was undertaken to acquire documentation for a database of the composition of selected minor fruits. The total phenolic (TPH), vitamin C, total carotene, and ß-carotene contents and antioxidant activity of selected minor fruits were determined by 1,1-diphenyl-2picryl hydrazyl (DPPH) scavenging and reducing power assays (RPA). Phenolic compounds were assessed using high-performance liquid chromatography coupled with a photodiode array detector and autosampler. Results revealed that minor fruits contain different phytochemicals, particularly TPH, ascorbic acid, total flavonoid (TF), ß-carotene, total carotenoid (TC), and total anthocyanin content (TAC); values ranged, respectively, 0.23-176.50 mg GAE/g, 16.67-664.92 mg/100 g, 2.26-150.02 mg QE/100 g, 1.41-6897.57 μg/100 g, 1.26-98.24 mg/100 g and 1.15-47.46 mg/100 g. In the parameters antioxidant activity, total antioxidant capacity, DPPH, reducing power capacity (RPC), ferric reducing antioxidant power (FRAP), metal chelating capacity (MCC), nitric oxide (NO), and free radical scavenging activity, IC50 ranged 0.01-278.24 μg of ascorbic acid/mg of extract, 39.70-250.00%, 3.21-634.00%, 0.02-1817.88 μM Fe2SO4/100g, 22.29-210.43%, 0.02-70.50%, and 4.98-856.70 μg/g, respectively. Among the identified and quantified phenolic acids, leading examples were gallic acid (279.06 mg/100 g), vanilic acid (43.77 mg/100 g), Þ-courmaric acid (178.96 mg/100 g), ferulic acid (20.44 mg/100 g), and lutein (91.13 μg/100 g) in aonla, day fruit, elephant apple, and bilimbi. Moreover, all selected minor fruits are rich sources of bioactive, biochemical, and antioxidant compounds with potential for use in therapeutic applications

    Bioactive Compounds and Biochemical and Antioxidant Properties of Selected Minor Indigenous Fruits in Bangladesh

    No full text
    Minor fruits are a potential source of antinutrients, but there is no complete primary data source in the Bangladeshi context. Therefore, the present study was undertaken to acquire documentation for a database of the composition of selected minor fruits. The total phenolic (TPH), vitamin C, total carotene, and ß-carotene contents and antioxidant activity of selected minor fruits were determined by 1,1-diphenyl-2picryl hydrazyl (DPPH) scavenging and reducing power assays (RPA). Phenolic compounds were assessed using high-performance liquid chromatography coupled with a photodiode array detector and autosampler. Results revealed that minor fruits contain different phytochemicals, particularly TPH, ascorbic acid, total flavonoid (TF), ß-carotene, total carotenoid (TC), and total anthocyanin content (TAC); values ranged, respectively, 0.23-176.50 mg GAE/g, 16.67-664.92 mg/100 g, 2.26-150.02 mg QE/100 g, 1.41-6897.57 μg/100 g, 1.26-98.24 mg/100 g and 1.15-47.46 mg/100 g. In the parameters antioxidant activity, total antioxidant capacity, DPPH, reducing power capacity (RPC), ferric reducing antioxidant power (FRAP), metal chelating capacity (MCC), nitric oxide (NO), and free radical scavenging activity, IC50 ranged 0.01-278.24 μg of ascorbic acid/mg of extract, 39.70-250.00%, 3.21-634.00%, 0.02-1817.88 μM Fe2SO4/100g, 22.29-210.43%, 0.02-70.50%, and 4.98-856.70 μg/g, respectively. Among the identified and quantified phenolic acids, leading examples were gallic acid (279.06 mg/100 g), vanilic acid (43.77 mg/100 g), Þ-courmaric acid (178.96 mg/100 g), ferulic acid (20.44 mg/100 g), and lutein (91.13 μg/100 g) in aonla, day fruit, elephant apple, and bilimbi. Moreover, all selected minor fruits are rich sources of bioactive, biochemical, and antioxidant compounds with potential for use in therapeutic applications

    Frequency rate of active hepatitis G virus infection among human immunodeficiency virus infected patients in Tehran

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    Background : Hepatitis virus infections are common in patients suffering from human immunodeficiency virus (HIV) infection due to similar transmission routes of these viruses. Hepatitis virus infections lead to impaired survival in HIV positive patients. In contrast to the expectations, some studies indicate that HGV infection slows down the progression and eventually death of AIDS patients. The aim of this study was to estimate the frequency of active HGV infection among HIV infected patients in Tehran.Material and Methods: Flow cytometric analysis of lymphocyte subpopulations was performed on blood samples of 103 patients with HIV infection referring to the central laboratory of Iranian blood transfusion organization. Their plasma samples were analyzed for the presence of HGV RNA by RT-PCR. HGV Positive cases were confirmed by PCR-ELISA. Results: Of 103 HIV-positive patients, 16 (15.5) were HGV RNA-positive. It was apparent that the frequency of HGV in patients with CD4 count above 500 cell/μl is higher. Conclusion: Sucha frequency is not high compared with those found in other studies. The high frequency of active HGV infection in patients with asymptomatic HIV infection may be due to the loss of active HGV infection in patients with advanced HIV infection

    TB-related catastrophic costs in Ethiopia

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    OBJECTIVES: To measure the progress towards reducing TB-related catastrophic costs in 19 zones of Amhara, Oromia, SNNP (Southern Nations and Nationalities, and Peoples) and Sidama Regions of Ethiopia. METHODS: A baseline survey was conducted in randomly selected health facilities from all districts within the 19 zones from November 2020 to February 2021. Interventions targeting the major drivers of catastrophic costs identified in the baseline survey, such as installation of 126 GeneXpert and 13 Truenat machines, securing connectivity of 372 GeneXpert, establishing alternative specimen referral systems, and capacity-building of health workers, were implemented. A follow-up survey was conducted from October to December 2022. The WHO generic tool was used to collect data based on probability proportional to size. Data were entered into STATA software, and the proportion of catastrophic costs was calculated and compared between the two surveys. RESULTS: A total of 433 and 397 patients participated in the baseline and follow-up surveys, respectively. The proportion of catastrophic costs reduced from 64.7% to 43.8% (P < 0.0001). The share of direct non-medical costs decreased from 76.2% to 19.2%, while medical and indirect costs increased from 11.6% and 12.3% to 30.4% and 52.4 %. CONCLUSION: The proportion of households facing TB-related catastrophic costs has significantly reduced over the 2-year period. However, it remains unacceptably high and varies among regions. Further reducing the catastrophic costs requires multisectoral response, reviewing the TB service exemption policy, further decentralisation and improving the quality of TB services
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