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70 result(s) for "Agarwal, Kavita"
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Screening of core filter layer for the development of respiratory mask to combat COVID-19
The severe outbreak of respiratory coronavirus disease 2019 has increased the significant demand of respiratory mask and its use become ubiquitous worldwide to control this unprecedented respiratory pandemic. The performance of a respiratory mask depends on the efficiency of the filter layer which is mostly made of polypropylene melt blown non-woven (PP-MB-NW). So far, very limited characterization data are available for the PPE-MB-NW in terms to achieve desired particulate filtration efficiency (PFE) against 0.3 µm size, which are imperative in order to facilitate the right selection of PP-MB-NW fabric for the development of mask. In present study, eight different kinds of PP-MB-NW fabrics (Sample A–H) of varied structural morphology are chosen. The different PP-MB-NW were characterized for its pore size and distribution by mercury porosimeter and BET surface area analyzer was explored first time to understand the importance of blind pore in PFE. The PP-MB-NW samples were characterized using scanning electron microscopy so as to know the surface morphology. The filtration efficiency, pressure drop and breathing resistance of various PP-MB-NW fabric samples are investigated in single and double layers combination against the particle size of 0.3, 0.5 and 1 µm. The samples which are having low pore dia, high solid fraction volume, and low air permeability has high filtration efficiency (> 90%) against 0.3 µm particle with high pressure drop (16.3–21.3 mm WC) and breathing resistance (1.42–1.92 mbar) when compared to rest of the samples. This study will pave the way for the judicial selection of right kind of filter layer i.e., PP-MB-NW fabric for the development of mask and it will be greatly helpful in manufacturing of mask in this present pandemic with desired PFE indicating considerable promise for defense against respiratory pandemic.
Comparison of 75 mg versus 150 mg aspirin for the prevention of preterm preeclampsia in high-risk women at a tertiary level hospital: study protocol for a randomized double-blind clinical trial
Background Hypertensive disorders of pregnancy (HDP) pose significant risks to maternal and fetal health, with substantial mortality and morbidity rates globally, particularly in developing countries. Pre-eclampsia (PE) accounts for a notable portion of maternal morbidity and mortality, with varied prevalence across regions within countries like India. Despite advancements, disparities in healthcare access persist, influencing outcomes. PE not only affects maternal health during pregnancy but also predisposes women to long-term cardiovascular complications, emphasizing the need for early screening and preventive measures. Methods This prospective randomized double-blind clinical trial aims to compare the efficacy and safety of 75 mg versus 150 mg aspirin for preventing preterm pre-eclampsia in high-risk women. Screen-positive women aged 18–45 years with singleton pregnancies between 12 and 16 weeks of gestational age will be enrolled. They will be randomized in a 1:1 ratio to receive either 75 mg or 150 mg of aspirin nightly until 37 weeks of pregnancy or earlier if preterm pre-eclampsia develops. Feto-maternal outcomes, including preterm pre-eclampsia incidence and neonatal and maternal complications, will be assessed. The sample size calculation based on expected proportions of preterm pre-eclampsia in both groups indicates a total of 370 participants (185 per group) accounting for 20% attrition. Discussion This prospective randomized double-blind clinical trial aims to compare the effectiveness and safety of two doses of aspirin (75 mg vs 150 mg) in preventing preterm pre-eclampsia in high-risk women. The potential implications of this study are significant, including the optimization of aspirin prophylaxis, the development of evidence-based guidelines, and comprehensive assessment of maternal and fetal outcomes. In conclusion, the results of this study have the potential to significantly impact clinical practice by enhancing maternal and perinatal health outcomes and contributing to evidence-based obstetric care. Trial registration Clinical Trials Registry-India CTRI/2023/12/060983. Trial was registered prospectively on 29 December 2023. Acknowledgement Number REF/2023/12/076358. https://acrobat.adobe.com/id/urn:aaid:sc:AP:15870322-f1f4-4460-900c-6e056ab83a44 .
Glycan cross-feeding supports mutualism between Fusobacterium and the vaginal microbiota
Women with bacterial vaginosis (BV), an imbalance of the vaginal microbiome, are more likely to be colonized by potential pathogens such as Fusobacterium nucleatum, a bacterium linked with intrauterine infection and preterm birth. However, the conditions and mechanisms supporting pathogen colonization during vaginal dysbiosis remain obscure. We demonstrate that sialidase activity, a diagnostic feature of BV, promoted F. nucleatum foraging and growth on mammalian sialoglycans, a nutrient resource that was otherwise inaccessible because of the lack of endogenous F. nucleatum sialidase. In mice with sialidase-producing vaginal microbiotas, mutant F. nucleatum unable to consume sialic acids was impaired in vaginal colonization. These experiments in mice also led to the discovery that F. nucleatum may also \"give back\" to the community by reinforcing sialidase activity, a biochemical feature of human dysbiosis. Using human vaginal bacterial communities, we show that F. nucleatum supported robust outgrowth of Gardnerella vaginalis, a major sialidase producer and one of the most abundant organisms in BV. These results illustrate that mutually beneficial relationships between vaginal bacteria support pathogen colonization and may help maintain features of dysbiosis. These findings challenge the simplistic dogma that the mere absence of \"healthy\" lactobacilli is the sole mechanism that creates a permissive environment for pathogens during vaginal dysbiosis. Given the ubiquity of F. nucleatum in the human mouth, these studies also suggest a possible mechanism underlying links between vaginal dysbiosis and oral sex.
Low-dose inoculation of Escherichia coli achieves robust vaginal colonization and results in ascending infection accompanied by severe uterine inflammation in mice
Escherichia coli infection of the female reproductive tract is a significant cause of disease in humans and animals, but simple animal models are lacking. Here we report that vaginal inoculation of uropathogenic E. coli strains UTI89 and CFT073 in non-pregnant, estrogen-treated mice resulted in robust colonization of the vagina and uterine horns, whereas titers of the lab strain MG1655 were significantly lower. Non-estrogenized mice also became colonized, but there was more variation in titers. A dose of 104 colony-forming units (CFU) UTI89 was sufficient to result in colonization in all estrogenized mice, and we also observed bacterial transfer between inoculated and uninoculated estrogenized cage mates. UTI89 infection led to inflammation and leukocyte infiltration into the uterine horns as evidenced by tissue histology. Flow cytometry experiments revealed that neutrophil, monocyte and eosinophil populations were significantly increased in infected uterine horns. This model is a simple way to study host-pathogen interactions in E. coli vaginal colonization and uterine infection. There are immediate implications for investigators studying urinary tract infection using mouse models, as few E. coli are required to achieve reproductive colonization, resulting in an additional, underappreciated mucosal reservoir.
Role of Hemoglobin and Serum Iron in Oral Submucous Fibrosis : A Clinical Study
Background. Oral submucous fibrosis is a chronic, insidious oral mucosal condition affecting the most parts of the oral cavity with high malignant transformation rate triggered by areca nut chewing, nutritional deficiencies, immunologic processes, and genetic predisposition. OSF causes significant hematological abnormalities resulting in anemia and a decrease in serum iron levels. Aim. The aim of this study was to estimate the hemoglobin and serum iron levels among patients with oral submucous fibrosis and to compare the values with healthy subjects. Materials and Methods. In this hospital-based study 30 diagnosed patients of OSMF and 15 healthy individuals were included, and the values of hemoglobin and serum iron levels were estimated using Sahli’s and Ferrene methods. Results. OSMF patients showed significantly lower levels of hemoglobin and serum iron when compared with the healthy subjects. Conclusion. The findings of the study emphasizes on the assessment of hemoglobin and serum iron for patients with oral submucous fibrosis. Also iron therapy should be instituted concomitantly with the initial diagnosis which helps to cease the further progression of the condition. Further extensive studies are indicated to understand the correlation between OSMF and iron deficiency.
Polymer-based nanocomposites as defence material
Nanotechnology has opened the doors for various novel defence applications, such as smart materials, novel fuel sources, energy storage devices, harder/lighter platforms and newer medical applications. Uses of composites instead of steel allow the possible assembling of lightweight aircraft, consequently reducing fuel consumption, CO 2 emissions and fuel costs. Because of their enhanced mechanical, electrical and thermal properties, these polymer nanocomposites and materials have been found in several defence-related areas, such as the military, automobile, electronics, food and leisure. This overview aims to provide insight into the rapidly developing capabilities of lightweight nanofiller-reinforced polymer nanocomposite materials and explore their potential uses in various defence-related applications.
Thermal and microwave-absorbing properties of doped polyaniline–epoxy nanocomposites for stealth applications
The thermal properties of polymeric nanocomposites can be examined using TGA and DSC techniques, while dielectric properties can be examined through simulated scattering (S11, S12, S21, and S22) parameters. Polyaniline (PAni) nanopowder was synthesized using chemical oxidative polymerization techniques. Consequently, the crystallite size and morphology of the synthesized powder were examined using the XRD, TEM, and FESEM techniques. Further, a series of polymeric nanocomposites was developed via wet mixing and compressor molding techniques for various volume percentages (54.0, 57.5, 60.1, and 61.7 vol%) of synthesized powder within PAni/epoxy composites. Consequently, dielectric and absorbing properties have been measured using a vector network analyzer and its software module. The computed complex permittivity data were used to evaluate the absorption for different thicknesses of samples. A minimum reflection loss of − 22.3 dB (> 99.9% absorption) was optimized with broadband frequency ranges. The unique heterostructures of nanocomposite are responsible for the enhanced absorption and shielding performance. Graphical abstract
Real-time photothermal degradation of methylene blue dye by CuS thin film grown using a fully automated spray pyrolysis
The real-time photothermal degradation of methylene blue (MB) dye was studied using CuS thin film (TF) as a photocatalyst. The polycrystalline CuS TFs were fabricated on precleaned glass substrates by an aqueous solution of copper chloride and thiourea using a fully automated spray pyrolysis technique by varying temperatures (250–400°C). The properties of deposited films were studied by XRD, SEM, UV–Vis–NIR spectroscopy, photoluminescence (PL) and Hall measurement. XRD results show that the CuS TFs crystallized in the cubic phase with an average crystallite size ~22–30 nm. CuS TF grown at higher temperatures (350°C, 400°C) exhibited very low strain of about 0.55 and 1%, respectively. Hall study revealed that films deposited at 400°C had good electrical parameters with mobility ( μ ) of 0.866 cm 2  V −1  s −1 , Carrier concentration ( p ) of 5.21 × 1019 cm −3 and conductivity ( σ ) of 49.4 Ω-cm −1 . The estimated optical bandgap of films were found to be in the range of 2.10–2.26 eV, revealing blue shift due to quantum size effects. The PL spectra showed two characteristic bands of the CuS films, at 422 nm and an intense green band at 504 nm. The copper sulphide TF showed high photocatalytic activities in a photo-decolourization of MB dye under irradiation of visible light, as CuS TF was able to completely decompose the dye in 160 min.
High Thermally Stable Polyurethane Nanocomposite Foam Containing Polydimethyl Siloxane and Carbonaceous Nanofillers
High thermally stable polyurethane-based nanocomposite (PU) foam reinforced with different (0.25 - 1.0) wt% of carbonaceous nanofillers, i.e., graphene oxide (GO), reduced graphene oxide (rGO), and carbon black (CB) with polydimethylsiloxane (PDMS), were prepared by melt blending method. PU nanocomposite foam was tested and characterized by several techniques to check its stability and suitability for use at high temperatures. The microstructure of PU nanocomposite foam was studied by Field Emission Electron Microscopy (FESEM). The phase separation and crystallinity of samples were analyzed by X-ray diffraction technique. The tensile strength and extension properties were evaluated. The tensile strength of PU-PDMS with 1.0 wt% GO was 58.9% more than that of neat PU-PDMS. The thermal properties of PU foam were investigated using a Thermogravimetric Analyser (TGA). At 650 °C temperature, PU foam having 1.0 wt% of the carbonaceous-based nanofillers (GO, CB and rGO) is more thermally stable than other wt.% of nanofillers and could be used for high-temperature applications.
Development of Low Density, Heat Resistant and Broadband Microwave Absorbing Materials (MAMs) for Stealth Applications
The development of low density and broadband microwave absorbers are the need of the hour to cater for the needs of all military platforms for stealth technology. The low density and broadband properties can be inculcated in microwave absorbers using dielectric lossy materials (e.g. carbon fibres, carbon nanotubes, carbon black, fullerene, graphite, graphene and silicon carbide fibre). Therefore, we designed low density and heat resistant microwave absorbing materials (MAMs) using a novel approach of ceramic fibre board manufacturing technology. The microwave absorbing composites were prepared with varying percentage of milled carbon fibres, discontinuous aluminosilicate fibres and silicone resin as the matrix. The physico-mechanical properties of microwave absorbing composites were determined. Reflection loss of microwave absorbing composites was measured in the frequency range 2–18 GHz by unique single horn interferometry technique. The electromagnetic properties were measured in X-band using free space measurement system. Based on these properties the effect of thickness on the microwave absorbing properties in X-band was simulated The effect of weight % variation of milled carbon fibres on the microwave absorbing properties of composites have been studied in the frequency range 2–18 GHz.