Vaccine Approaches for Pandemic COVID-19: An Overview

The coronavirus strain, SARS-CoV-2 causative agent of the pandemic viral pneumonia disease COVID-19, identified in the late 2019. Unfortunately, there is no vaccine or therapeutics available to control the disease. Although, earlier research efforts of SARS pandemic (2003) provides the precious information to the researchers for fast track vaccine development. Research efforts for vaccine development of COVID-19 pandemic are unprecedented in terms of promising time period. The inactivated whole virus-based SARS-CoV-2 vaccine is first one developed and entered into clinical trial. However, later on after announce of complete genome sequence of SARS-CoV-2, vaccine based on recombinant viral vector, nucleic acid and immunogenic fragment also introduced. Previous experience of undesired immunopotentiation in SARS-CoV studies represents, vaccine safety should be the main concern.  Researchers believe that next generation vaccine approaches using recombinant technology such as viral vector or subunit protein-based vaccine will be more effective and safer. This review describes brief information of the major vaccine candidates and the current scenario of vaccine approaches against COVID-19 pandemic

Curcumin Alleviates Matrix Metalloproteinase-3 and -9 Activities during Eradication of Helicobacter pylori Infection in Cultured Cells and Mice

Current therapy-regimens against Helicobacter pylori (Hp) infections have considerable failure rates and adverse side effects that urge the quest for an effective alternative therapy. We have shown that curcumin is capable of eradicating Hp-infection in mice. Here we examine the mechanism by which curcumin protects Hp infection in cultured cells and mice. Since, MMP-3 and -9 are inflammatory molecules associated to the pathogenesis of Hp-infection, we investigated the role of curcumin on inflammatory MMPs as well as proinflammatory molecules. Curcumin dose dependently suppressed MMP-3 and -9 expression in Hp infected human gastric epithelial (AGS) cells. Consistently, Hp-eradication by curcumin-therapy involved significant downregulation of MMP-3 and -9 activities and expression in both cytotoxic associated gene (cag)+ve and cag-ve Hp-infected mouse gastric tissues. Moreover, we demonstrate that the conventional triple therapy (TT) alleviated MMP-3 and -9 activities less efficiently than curcumin and curcumin's action on MMPs was linked to decreased pro-inflammatory molecules and activator protein-1 activation in Hp-infected gastric tissues. Although both curcumin and TT were associated with MMP-3 and -9 downregulation during Hp-eradication, but unlike TT, curcumin enhanced peroxisome proliferator-activated receptor-γ and inhibitor of kappa B-α. These data indicate that curcumin-mediated healing of Hp-infection involves regulation of MMP-3 and -9 activities

Constraints on dark matter-nucleon effective couplings in the presence of kinematically distinct halo substructures using the DEAP-3600 detector

DEAP-3600 is a single-phase liquid argon detector aiming to directly detect Weakly Interacting Massive Particles (WIMPs), located at SNOLAB (Sudbury, Canada). After analyzing data taken during the first year of operation, a null result was used to place an upper bound on the WIMP-nucleon spin-independent, isoscalar cross section. This study reinterprets this result within a Non-Relativistic Effective Field Theory framework, and further examines how various possible substructures in the local dark matter halo may affect these constraints. Such substructures are hinted at by kinematic structures in the local stellar distribution observed by the Gaia satellite and other recent astronomical surveys. These include the Gaia Sausage (or Enceladus), as well as a number of distinct streams identified in recent studies. Limits are presented for the coupling strength of the effective contact interaction operators $\mathcal{O}_1$, $\mathcal{O}_3$, $\mathcal{O}_5$, $\mathcal{O}_8$, and $\mathcal{O}_{11}$, considering isoscalar, isovector, and xenonphobic scenarios, as well as the specific operators corresponding to millicharge, magnetic dipole, electric dipole, and anapole interactions. The effects of halo substructures on each of these operators are explored as well, showing that the $\mathcal{O}_5$ and $\mathcal{O}_8$ operators are particularly sensitive to the velocity distribution, even at dark matter masses above 100 GeV/$c^2$

The liquid-argon scintillation pulseshape in DEAP-3600

DEAP-3600 is a liquid-argon scintillation detector looking for dark matter. Scintillation events in the liquid argon (LAr) are registered by 255 photomultiplier tubes (PMTs), and pulseshape discrimination (PSD) is used to suppress electromagnetic background events. The excellent PSD performance of LAr makes it a viable target for dark matter searches, and the LAr scintillation pulseshape discussed here is the basis of PSD. The observed pulseshape is a combination of LAr scintillation physics with detector effects. We present a model for the pulseshape of electromagnetic background events in the energy region of interest for dark matter searches. The model is composed of (a) LAr scintillation physics, including the so-called intermediate component, (b) the time response of the TPB wavelength shifter, including delayed TPB emission at O(ms) time-scales, and c) PMT response. TPB is the wavelength shifter of choice in most LAr detectors. We find that approximately 10% of the intensity of the wavelength-shifted light is in a long-lived state of TPB. This causes light from an event to spill into subsequent events to an extent not usually accounted for in the design and data analysis of LAr-based detectors

A Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics

The nature of dark matter and properties of neutrinos are among the mostpressing issues in contemporary particle physics. The dual-phase xenontime-projection chamber is the leading technology to cover the availableparameter space for Weakly Interacting Massive Particles (WIMPs), whilefeaturing extensive sensitivity to many alternative dark matter candidates.These detectors can also study neutrinos through neutrinoless double-beta decayand through a variety of astrophysical sources. A next-generation xenon-baseddetector will therefore be a true multi-purpose observatory to significantlyadvance particle physics, nuclear physics, astrophysics, solar physics, andcosmology. This review article presents the science cases for such a detector.<br

Scoping review of indicators and methods of measurement used to evaluate the impact of dog population management interventions

Background: Dogs are ubiquitous in human society and attempts to manage their populations are common to most countries. Managing dog populations is achieved through a range of interventions to suit the dog population dynamics and dog ownership characteristics of the location, with a number of potential impacts or goals in mind. Impact assessment provides the opportunity for interventions to identify areas of inefficiencies for improvement and build evidence of positive change. Methods: This scoping review collates 26 studies that have assessed the impacts of dog population management interventions. Results: It reports the use of 29 indicators of change under 8 categories of impact and describes variation in the methods used to measure these indicators. Conclusion: The relatively few published examples of impact assessment in dog population management suggest this field is in its infancy; however this review highlights those notable exceptions. By describing those indicators and methods of measurement that have been reported thus far, and apparent barriers to efficient assessment, this review aims to support and direct future impact assessment

Constraints on dark matter-nucleon effective couplings in the presence of kinematically distinct halo substructures using the DEAP-3600 detector

DEAP-3600 is a single-phase liquid argon detector aiming to directly detect weakly interacting massive particles (WIMPs), located at SNOLAB (Sudbury, Canada). After analyzing data taken during the first year of operation, a null result was used to place an upper bound on the WIMP-nucleon, spin-independent, isoscalar cross section. This study reinterprets this result within a nonrelativistic effective field theory framework and further examines how various possible substructures in the local dark matter halo may affect these constraints. Such substructures are hinted at by kinematic structures in the local stellar distribution observed by the Gaia satellite and other recent astronomical surveys. These include the Gaia Sausage (or Enceladus), as well as a number of distinct streams identified in recent studies. Limits are presented for the coupling strength of the effective contact interaction operators O1, O3, O5, O8, and O11, considering isoscalar, isovector, and xenonphobic scenarios, as well as the specific operators corresponding to millicharge, magnetic dipole, electric dipole, and anapole interactions. The effects of halo substructures on each of these operators are explored as well, showing that the O5 and O8 operators are particularly sensitive to the velocity distribution, even at dark matter masses above 100 GeV=c

Pulse-shape discrimination against low-energy Ar-39 beta decays in liquid argon with 4.5 tonne-years of DEAP-3600 data

The DEAP-3600 detector searches for the scintillation signal from dark matter particles scattering on a 3.3 tonne liquid argon target. The largest background comes from 39Ar beta decays and is suppressed using pulse-shape discrimination (PSD). We use two types of PSD estimator: the prompt-fraction, which considers the fraction of the scintillation signal in a narrow and a wide time window around the event peak, and the log-likelihood-ratio, which compares the observed photon arrival times to a signal and a background model. We furthermore use two algorithms to determine the number of photons detected at a given time: (1) simply dividing the charge of each PMT pulse by the mean single-photoelectron charge, and (2) a likelihood analysis that considers the probability to detect a certain number of photons at a given time, based on a model for the scintillation pulse shape and for afterpulsing in the light detectors. The prompt-fraction performs approximately as well as the log-likelihood-ratio PSD algorithm if the photon detection times are not biased by detector effects. We explain this result using a model for the information carried by scintillation photons as a function of the time when they are detected