1,853 research outputs found

    AQUEOUS LIQUID SOLUTIONS FOR LI-LIQUID BATTERY

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    poster abstractThe evolvement of Lithium-ion battery industries has begun to carry the industries to step in a new revolution. Consequently, high demand in high energy density batteries in many electronic and electrical appliances, espe-cially energy storage industries been emerged. This new type of batteries has been in extensive research, such as lithium-water battery. Lithium-water battery is a newly developed battery with lithium as the anode and water as the cathode. Lithium is known as one of the most reac-tive metals in periodic table. Therefore, rigorous reaction will be observed when lithium is reacted with water and hence potentially providing an ex-tremely high energy density. This rigorous reaction can be converted into electrical energy and can be stored in a cell. Lithium-water battery is novel and hence, there is no standardized design. In this presentation, lithium anode is separated from water by liquid electrolyte and a ceramic solid electrolyte. The glass-ceramic solid electro-lyte which has Li1.3Ti1.7Al0.3(PO4)3 composition plays an important role of the design of this lithiumā€“water battery. The main purpose of the solid electro-lyte is to separate water from lithium, avoiding a dangerous exothermic re-action. Also, the presence of the super-ionic conductor ceramic can provide very high lithium ion conductivity. The different sizes of solid electrolytes were used in designing Li-liquid battery cell. The effect of the electrolyte size on the voltage of the cell was studied to optimize the cell design. Then, the aqueous solutions containing different chemicals were tested as the liquid cathodes, and their electro-chemical performance were compared to those of the pure DI water. Further results will be presented in the poster presentation

    Normalizing Community Mask-Wearing: A Cluster Randomized Trial in Bangladesh

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    Background: A growing body of scientiļ¬c evidence suggests that face masks can slow the spread of COVID-19 and save lives, but mask usage remains low across many parts of the world, and strategies to increase mask usage remain untested and unclear. Methods: We conducted a cluster-randomized trial of community-level mask promotion in rural Bangladesh involving 341,830 adults in 600 villages. We employed a series of strategies to promote mask usage, including free household distribution of surgical or cloth masks, distribution and promotion at markets and mosques, mask advocacy by Imams during Friday prayers, role modeling by local leaders, promoters periodically monitoring passers-by and reminding people to put on masks, village police accompanying those mask promoters, providing monetary rewards or certiļ¬cates to villages if mask-wearing rate improves, public signaling of mask-wearing via signage, text message reminders, messaging emphasizing either altruistic or self-protection motives for mask-wearing, and extracting verbal commitments from households. The primary objective was to assess which of these interventions would increase proper (covering nose and mouth) wearing of face masks, and secondarily, whether mask promotion unintentionally creates moral hazard and decreases social distancing. This analysis is part of larger study evaluating the eļ¬€ect of mask-wearing on transmission of SARS-CoV-2. Results: There were 64,937 households in the intervention group and 64,183 households in the control group; study recruitment has ended. In the control group, proper mask-wearing was practiced by 13% of those observed across the study period. Free distribution of masks along with role modeling by community leaders produced only small increases in mask usage during pilot interventions. Adding periodic monitoring by mask promoters to remind people in streets and public places to put on the masks we provided increased proper mask-wearing by 29.0 percentage points (95% CI: 26.7% - 31.3%). This tripling of mask usage was sustained over all 10 weeks of surveillance, which includes a period after intervention activities ended. Physical distancing, measured as the fraction of individuals at least one armā€™s length apart, also increased by 5.2 percentage points (95% CI: 4.2%-6.3%). Beyond the core intervention package comprised of free distribution and promotion at households/mosques/markets, leader endorsements plus periodic monitoring and reminders, several elements had no additional eļ¬€ect on mask wearing, including: text reminders, public signage commitments, monetary or non-monetary incentives, altruistic messaging or verbal commitments, or village police accompanying the mask promoters (the last not cross-randomized, but assessed in panel data). No adverse events were reported during the study period. Conclusions: Our intervention demonstrates a scalable and cost-eļ¬€ective method to promote mask adoption and save lives, and identiļ¬es a precise combination of intervention activities that were necessary. Comparisons between pilots shows that free mask distribution alone is not suļ¬€icient to increase mask-wearing, but adding periodic monitoring in public places to remind people to wear the distributed masks had large eļ¬€ects on behavior. The absence of any further eļ¬€ect of the village police suggests that the operative mechanism is not any threat of formal legal sanctions, but shame and peopleā€™s aversion to a light informal social sanction. The persistence of eļ¬€ects for 10 weeks and after the end of the active intervention period, as well as increases in physical distancing, all point to changes in social norms as a key driver of behavior change. Our cross-randomizations suggest that improved mask-wearing norms can be achieved without incentives that require costly monitoring, that aesthetic design choices and colors can influence mask-wearing, and that surgical masks with a substantially higher ļ¬ltration eļ¬€iciency can be a cost-eļ¬€ective alternative to cloth masks (1/3 the cost) and are equally or more likely to be worn. Implementing these interventions ā€“ including distribution of free masks, and the information campaign, reminders, encouragement ā€“ cost 2.30āˆ’2.30-3.75 per villager, or between 8and8 and 13 per person adopting a mask. Combined with existing estimates of the eļ¬€icacy of masks in preventing COVID-19 deaths, this implies that the intervention cost 28,000āˆ’28,000-66,000 per life saved. Beyond reducing the transmission of COVID-19, mask distribution is likely to be a cost-eļ¬€ective strategy to prevent future respiratory disease outbreaks

    Structure and Recognition of a Novel HIV-1 gp120-gp41 Interface Antibody that Caused MPER Exposure through Viral Escape

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    A comprehensive understanding of the regions on HIV-1 envelope trimers targeted by broadly neutralizing antibodies may contribute to rational design of an HIV-1 vaccine. We previously identified a participant in the CAPRISA cohort, CAP248, who developed trimer-specific antibodies capable of neutralizing 60% of heterologous viruses at three years post-infection. Here, we report the isolation by B cell culture of monoclonal antibody CAP248-2B, which targets a novel membrane proximal epitope including elements of gp120 and gp41. Despite low maximum inhibition plateaus, often below 50% inhibitory concentrations, the breadth of CAP248-2B significantly correlated with donor plasma. Site-directed mutagenesis, X-ray crystallography, and negative-stain electron microscopy 3D reconstructions revealed how CAP248-2B recognizes a cleavage-dependent epitope that includes the gp120 C terminus. While this epitope is distinct, it overlapped in parts of gp41 with the epitopes of broadly neutralizing antibodies PGT151, VRC34, 35O22, 3BC315, and 10E8. CAP248-2B has a conformationally variable paratope with an unusually long 19 amino acid light chain third complementarity determining region. Two phenylalanines at the loop apex were predicted by docking and mutagenesis data to interact with the viral membrane. Neutralization by CAP248-2B is not dependent on any single glycan proximal to its epitope, and low neutralization plateaus could not be completely explained by N- or O-linked glycosylation pathway inhibitors, furin co-transfection, or pre-incubation with soluble CD4. Viral escape from CAP248-2B involved a cluster of rare mutations in the gp120-gp41 cleavage sites. Simultaneous introduction of these mutations into heterologous viruses abrogated neutralization by CAP248-2B, but enhanced neutralization sensitivity to 35O22, 4E10, and 10E8 by 10-100-fold. Altogether, this study expands the region of the HIV-1 gp120-gp41 quaternary interface that is a target for broadly neutralizing antibodies and identifies a set of mutations in the gp120 C terminus that exposes the membrane-proximal external region of gp41, with potential utility in HIV vaccine design

    Ubiquitous outflows in DEEP2 spectra of star-forming galaxies at z=1.4

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    Galactic winds are a prime suspect for the metal enrichment of the intergalactic medium and may have a strong influence on the chemical evolution of galaxies and the nature of QSO absorption line systems. We use a sample of 1406 galaxy spectra at z~1.4 from the DEEP2 redshift survey to show that blueshifted Mg II 2796, 2803 A absorption is ubiquitous in starforming galaxies at this epoch. This is the first detection of frequent outflowing galactic winds at z~1. The presence and depth of absorption are independent of AGN spectral signatures or galaxy morphology; major mergers are not a prerequisite for driving a galactic wind from massive galaxies. Outflows are found in coadded spectra of galaxies spanning a range of 30x in stellar mass and 10x in star formation rate (SFR), calibrated from K-band and from MIPS IR fluxes. The outflows have column densities of order N_H ~ 10^20 cm^-2 and characteristic velocities of ~ 300-500 km/sec, with absorption seen out to 1000 km/sec in the most massive, highest SFR galaxies. The velocities suggest that the outflowing gas can escape into the IGM and that massive galaxies can produce cosmologically and chemically significant outflows. Both the Mg II equivalent width and the outflow velocity are larger for galaxies of higher stellar mass and SFR, with V_wind ~ SFR^0.3, similar to the scaling in low redshift IR-luminous galaxies. The high frequency of outflows in the star-forming galaxy population at z~1 indicates that galactic winds occur in the progenitors of massive spirals as well as those of ellipticals. The increase of outflow velocity with mass and SFR constrains theoretical models of galaxy evolution that include feedback from galactic winds, and may favor momentum-driven models for the wind physics.Comment: Accepted by ApJ. 25 pages, 17 figures. Revised to add discussions of intervening absorbers and AGN-driven outflows; conclusions unchange

    Formation of Corrugated n = 1 2D Tin Iodide Perovskites and Their Use as Lead-Free Solar Absorbers

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    Major strides have been made in the development of materials and devices based around low-dimensional hybrid group 14 metal halide perovskites. Thus far, this work has mostly focused upon compounds containing highly toxic Pb, with the analogous less toxic Sn materials being comparatively poorly evolved. In response, the study herein aims to (i) provide insight into the impact of templating cation upon the structure of n = 1 2D tin iodide perovskites (where n refers to the number of contiguous two-dimensional (2D) inorganic layers, i.e., not separated by organic cations), and (ii) examine their potential as light absorbers for photovoltaic (PV) cells. It was discovered through systematic tuning of organic dications, that imidazolium rings are able to induce formation of (110)-oriented materials, including the examples of ā€œ3 Ɨ 3ā€ corrugated Sn-I perovskites. This structural outcome is a consequence of a combination of supramolecular interactions of the two endocyclic N-atoms in the imidazolium functionalities with the Sn-I framework and the higher tendency of Sn2+ ions to stereochemically express their 5s2 lone pairs relative to the 6s2 electrons of Pb2+. More importantly, the resulting materials feature very short separations between their 2D inorganic layers with iodideā€“iodide (IĀ·Ā·Ā·I) contacts as small as 4.174 ƅ, which is amongst the shortest ever recorded for 2D tin iodide perovskites. The proximate inorganic distances, combined with the polarizable nature of the imidazolium moiety, eases the separation of photogenerated charge within the materials. This is evident from the excitonic activation energies as low as 83(10) meV, measured for ImEA[SnI4]. When combined with superior light absorption capabilities relative to their lead congeners, this allowed fabrication of lead-free solar cells with incident photon-to-current and power conversion efficiencies of up to 70 % and 2.26 %, respectively, which are amongst the highest values reported for pure n = 1 2D group 14 metal halide perovskites. In fact, these values are superior to the corresponding lead iodide material, which demonstrates that 2D Sn-based materials have significant potential as less toxic alternatives to their Pb counterparts

    Whole blood transcriptome changes following controlled human malaria infection in malaria pre-exposed volunteers correlate with parasite prepatent period

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    Malaria continues to be one of mankind's most devastating diseases despite the many and varied efforts to combat it. Indispensable for malaria elimination and eventual eradication is the development of effective vaccines. Controlled human malaria infection (CHMI) is an invaluable tool for vaccine efficacy assessment and investigation of early immunological and molecular responses against Plasmodium falciparum infection. Here, we investigated gene expression changes following CHMI using RNA-Seq. Peripheral blood samples were collected in Bagamoyo, Tanzania, from ten adults who were injected intradermally (ID) with 2.5x104 aseptic, purified, cryopreserved P. falciparum sporozoites (SanariaĀ® PfSPZ Challenge). A total of 2,758 genes were identified as differentially expressed following CHMI. Transcriptional changes were most pronounced on day 5 after inoculation, during the clinically silent liver phase. A secondary analysis, grouping the volunteers according to their prepatent period duration, identified 265 genes whose expression levels were linked to time of blood stage parasitemia detection. Gene modules associated with these 265 genes were linked to regulation of transcription, cell cycle, phosphatidylinositol signaling and erythrocyte development. Our study showed that in malaria pre-exposed volunteers, parasite prepatent period in each individual is linked to magnitude and timing of early gene expression changes after ID CHMI

    Impact of a clinical pharmacist on ultrasound-guided venous thromboembolism screening in hospitalized COVID-19 patients: a pilot prospective study

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    Background The recognition, prevention and treatment of venous thromboembolism (VTE) remains a major challenge in the face of the recent COVID-19 pandemic which has been associated with significant cardiovascular, renal, respiratory and hematologic complications related to hypercoagulability. There has been little literature thus far on the utility of screening ultrasound and the role of the clinical pharmacist in treating these patients. Methods We present a prospective pilot program of thirty-one consecutive COVID-19 patients who were provided four extremity screening ultrasounds for VTE on admission. This was coordinated by a clinical pharmacist as part of a multidisciplinary approach. Quantitative and qualitative data were recorded with the goal of describing the utility of the clinical pharmacist in ultrasound screening. Data collected include demographics, information on clinical symptoms or signs at presentation, and laboratory and radiologic results during the hospitalization from each individual electronic medical record. Results Nine of the thirty-one patients presented with VTE. Of the nine patients, there were twenty-two total clotted vessels, all of which were asymptomatic. The clinical pharmacist, as the coordinator for a multidisciplinary COVID-19 associated coagulopathy management team, drafted a screening and treatment protocol for anticoagulation prophylaxis and therapy of VTE after ultrasound findings. Conclusion VTE screening of hospitalized COVID-19 patients reveals a significant number of asymptomatic VTEs and justifies diagnostic, prophylactic, and treatment measures coordinated by a clinical pharmacist

    Association of HIV-Specific and Total CD8+ T Memory Phenotypes in Subtype C HIV-1 Infection with Viral Set Point.

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    Understanding early immunological events during HIV-1 infection that may set the course of disease progression is important for identifying correlates of viral control. This study explores the association of differentiation profiles of HIV-specific and total memory CD8+ T cells with viral set point. A cohort of 47 HIV-1-infected individuals, with differing viral set points at 12 mo, were recruited during acute infection. We identified that the magnitude of IFN-Ī³+ T cell responses at 6 mo postinfection did not associate with viral set point at 12 mo. A subset of 16 individuals was further studied to characterize CD8+ T cells for expression patterns of markers for memory differentiation, survival (CD127), senescence (CD57), and negative regulation (programmed death-1). We show that viral control and the predicted tempo of HIV disease progression in the first year of infection was associated with a synchronous differentiation of HIV-specific and total CD8+ memory subpopulations. At 6ā€“9 mo postinfection, those with low viral set points had a significantly higher proportion of early differentiated HIV-specific and total memory CD8+ cells of a central memory (CD45RO+CD27+CCR7+) and intermediate memory (CD45ROāˆ’CD27+CCR7āˆ’) phenotype. Those with high viral set points possessed significantly larger frequencies of effector memory (CD45RO+CD27āˆ’CCR7āˆ’) cells. The proportions of memory subsets significantly correlated with CD38+CD8+ T cells. Thus, it is likely that a high Ag burden resulting in generalized immune activation may drive differentiation of HIV-specific and total memory CD8+ T cells
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