Publications by authors named "Saurabh Dixit"

The emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and onset of the coronavirus disease-19 (COVID-19) pandemic led to an immediate need for therapeutic treatment options. Therapeutic antibodies were developed to fill a gap when traditional antivirals were not available. In late 2020, the United States Government undertook an effort to compare candidate therapeutic antibodies in virus neutralization assays and in the hamster model of SARS-CoV-2 infection.

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Highly anisotropic materials show great promise for spatial control and the manipulation of polaritons. In-plane hyperbolic phonon polaritons (HPhPs) supported by α-phase molybdenum trioxide (MoO) allow for wave propagation with a high directionality due to the hyperbola-shaped isofrequency contour (IFC). However, the IFC prohibits propagations along the [001] axis, hindering information or energy flow.

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Article Synopsis
  • This study looked at how a virus called SARS-CoV-2 affects three different groups of golden hamsters: older ones, younger ones, and those with a special human receptor.
  • Researchers used a special imaging technique called F-FDG PET/CT to track how sick the hamsters got after being exposed to the virus.
  • They found that older hamsters got much sicker than the younger ones, while the hamsters with the human receptor had serious brain problems but less severe lung issues.
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The COVID-19 pandemic spurred the rapid development of a range of therapeutic antibody treatments. As part of the US government's COVID-19 therapeutic response, a research team was assembled to support assay and animal model development to assess activity for therapeutics candidates against SARS-CoV-2. Candidate treatments included monoclonal antibodies, antibody cocktails, and products derived from blood donated by convalescent patients.

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Experimental vaccines for the deadly zoonotic Nipah (NiV), Hendra (HeV), and Ebola (EBOV) viruses have focused on targeting individual viruses, although their geographical and bat reservoir host overlaps warrant creation of multivalent vaccines. Here we explored whether replication-incompetent pseudotyped vesicular stomatitis virus (VSV) virions or NiV-based virus-like particles (VLPs) were suitable multivalent vaccine platforms by co-incorporating multiple surface glycoproteins from NiV, HeV, and EBOV onto these virions. We then enhanced the vaccines' thermotolerance using carbohydrates to enhance applicability in global regions that lack cold-chain infrastructure.

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Humanity has faced three recent outbreaks of novel betacoronaviruses, emphasizing the need to develop approaches that broadly target coronaviruses. Here, we identify 55 monoclonal antibodies from COVID-19 convalescent donors that bind diverse betacoronavirus spike proteins. Most antibodies targeted an S2 epitope that included the K814 residue and were non-neutralizing.

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High-pressure-torsion (HPT) processing introduces a large density of dislocations that form sub-grain boundaries within the refined nano-scale structure, leading to changes in precipitate morphology compared to hot-rolled maraging steels. The impact of such nanostructuring on the deformation and fracture micro-mechanisms is being reported for the first time usingcharacterization techniques along with transmission electron microscopy and atom probe tomography analysis, in this study. Digital image correlation has been used to quantify the full field strain maps in regions of severe strain localization as well as to determine the fracture toughness through critical crack tip opening displacements.

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The potential for future coronavirus outbreaks highlights the need to broadly target this group of pathogens. We used an epitope-agnostic approach to identify six monoclonal antibodies that bind to spike proteins from all seven human-infecting coronaviruses. All six antibodies target the conserved fusion peptide region adjacent to the S2' cleavage site.

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Unlabelled: The potential for future coronavirus outbreaks highlights the need to develop strategies and tools to broadly target this group of pathogens. Here, using an epitope-agnostic approach, we identified six monoclonal antibodies that bound to spike proteins from all seven human-infecting coronaviruses. Epitope mapping revealed that all six antibodies target the conserved fusion peptide region adjacent to the S2' cleavage site.

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The recent discovery of natural biaxial hyperbolicity in van der Waals crystals, such as -MoO, has opened up new avenues for mid-IR nanophotonics due to their deep subwavelength phonon polaritons. However, a significant challenge is the lack of active tunability of these hyperbolic phonon polaritons. In this work, we investigate heterostructures of graphene and -MoO for actively tunable hybrid plasmon phonon polariton modes via electrostatic gating in the mid-infrared spectral region.

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Academic research in tourism and hospitality sector adds value directly to the way the industry grows and develops. Scholars in this area struggle with the pressures to publish in high ranking journals. The present study attempts to help doctoral students and tourism educators in identifying emerging themes in the tourism and hospitality arising out after COVID-19 pandemic.

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Preerythrocytic vaccines prevent malaria by targeting parasites in the clinically silent sporozoite and liver stages and preventing progression to the virulent blood stages. The leading preerythrocytic vaccine, RTS,S/AS01E (Mosquirix), entered implementation programs in 2019 and targets the major sporozoite surface antigen, circumsporozoite protein (CSP). However, in phase III clinical trials, RTS,S conferred partial protection with limited durability, indicating a need to improve CSP-based vaccination.

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As the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic expanded, it was clear that effective testing for the presence of neutralizing antibodies in the blood of convalescent patients would be critical for development of plasma-based therapeutic approaches. To address the need for a high-quality neutralization assay against SARS-CoV-2, a previously established fluorescence reduction neutralization assay (FRNA) against Middle East respiratory syndrome coronavirus (MERS-CoV) was modified and optimized. The SARS-CoV-2 FRNA provides a quantitative assessment of a large number of infected cells through use of a high-content imaging system.

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Recently we reported the immune-potentiating capacity of a nanovaccine (PLGA-rMOMP) comprising rMOMP (recombinant major outer membrane protein) encapsulated in extended-releasing PLGA [poly (D, L-lactide-co-glycolide) (85:15)] nanoparticles. Here we hypothesized that PLGA-rMOMP would bolster immune-effector mechanisms to confer protective efficacy in mice against a genital challenge and re-challenge. Female BALB/c mice received three immunizations, either subcutaneously (SC) or intranasally (IN), before receiving an intravaginal challenge with on day 49 and a re-challenge on day 170.

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Mid-infrared (IR) spectral region is of immense importance for astronomy, medical diagnosis, security and imaging due to the existence of the vibrational modes of many important molecules in this spectral range. Therefore, there is a particular interest in miniaturization and integration of IR optical components. To this end, 2D van der Waals (vdW) crystals have shown great potential owing to their ease of integration with other optoelectronic platforms and room temperature operation.

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As the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic was expanding, it was clear that effective testing for the presence of neutralizing antibodies in the blood of convalescent patients would be critical for development of plasma-based therapeutic approaches. To address the need for a high-quality neutralization assay against SARS-CoV-2, a previously established fluorescence reduction neutralization assay (FRNA) against Middle East respiratory syndrome coronavirus (MERS-CoV) was modified and optimized. The SARS-CoV-2 FRNA provides a quantitative assessment of a large number of infected cells through use of a high-content imaging system.

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The immunopathology of chlamydial diseases is exacerbated by a broad-spectrum of inflammatory mediators, which we reported are inhibited by IL-10 in macrophages. However, the chlamydial protein moiety that induces the inflammatory mediators and the mechanisms by which IL-10 inhibits them are unknown. We hypothesized that major outer membrane protein (MOMP) mediates its disease pathogenesis, and the suppressor of cytokine signaling (SOCS)1 and SOCS3 proteins are mediators of the IL-10 inhibitory actions.

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Vaccine developmental strategies are utilizing antigens encapsulated in biodegradable polymeric nanoparticles. Here, we developed a Chlamydia nanovaccine (PLGA-rMOMP) by encapsulating its recombinant major outer membrane protein (rMOMP) in the extended-releasing and self-adjuvanting PLGA [poly (D, L-lactide-co-glycolide) (85:15)] nanoparticles. PLGA-rMOMP was small (nanometer size), round and smooth, thermally stable, and exhibited a sustained release of rMOMP.

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Inflammation, as induced by the presence of cytokines and chemokines, is an integral part of chlamydial infections. The anti-inflammatory cytokine, interleukin (IL)-10, has been reported to efficiently suppress the secretion of inflammatory cytokines triggered by in mouse macrophages. Though IL-10 is employed in clinical applications, its therapeutic usage is limited due to its short half-life.

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Objective: To investigate the toxicity and antibacterial application of antimicrobial peptide-functionalized silver-coated carbon nanotubes against Staphylococcus infection using a full thickness human three-dimensional skin model.

Materials And Methods: The three-dimensional skin formation on the scaffolds was characterized by electron microscopy and investigation of several skin cell markers by real time-reverse transcriptase polymerase chain reaction. Functionalized silver-coated carbon nanotubes were prepared using carboxylated silver-coated carbon nanotubes with antimicrobial peptides such as TP359, TP226 and TP557.

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Article Synopsis
  • The study focuses on a new biodegradable co-polymeric nanovaccine called PPM that targets chlamydia, enhancing immune responses in a mouse model for genital tract infections.
  • Mice that received the PPM vaccine showed significant protection, evidenced by lower bacterial loads and heightened CD4 T-cell responses, particularly increases in specific antibodies like IgG1 and IgA.
  • The findings indicate that PPM successfully initiated both Th1 and Th2 immune responses, ultimately leading to strong protective effects against chlamydial infection, marking a promising advance in vaccine technology.
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Article Synopsis
  • The text discusses the public health challenges posed by Chlamydia-related diseases, such as trachoma and pelvic inflammatory disease, highlighting the need for an effective human vaccine due to failures in current prevention methods.
  • It emphasizes the potential of biodegradable polymeric nanoparticles as a promising delivery system for vaccine antigens to create a successful Chlamydia vaccine for humans.
  • The review suggests that advancements in research and positive results from animal model testing may lead to imminent clinical trials for Chlamydia vaccines, targeting both trachoma and reproductive health issues.
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We previously developed a Chlamydia trachomatis nanovaccine (PPM) by encapsulating a chlamydial M278 peptide within poly(lactic acid)-poly(ethylene glycol) biodegradable nanoparticles that immunopotentiated Chlamydia-specific immune effector responses in mice. Herein, we investigated the mechanistic interactions of PPM with mouse bone marrow-derived dendritic cells (DCs) for its uptake, trafficking, and T cell activation. Our results reveal that PPM triggered enhanced expression of effector cytokines and chemokines, surface activation markers (Cd1d2, Fcgr1), pathogen-sensing receptors (TLR2, Nod1), co-stimulatory (CD40, CD80, CD86) and MHC class I and II molecules.

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The repair or replacement of damaged skins is still an important, challenging public health problem. Immune acceptance and long-term survival of skin grafts represent the major problem to overcome in grafting given that in most situations autografts cannot be used. The emergence of artificial skin substitutes provides alternative treatment with the capacity to reduce the dependency on the increasing demand of cadaver skin grafts.

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