63 research outputs found
Fuzzy modeling for the spread of influenza virus and its possible control
In this paper, we analyze a model of Influenza spread with an asymptotic transmission rate, wherein the disease transmission rate and death rate are considered as fuzzy sets. Comparative studies of the equilibrium points of the disease for the classical and fuzzy models are performed. Using the concept of probability measure and fuzzy expected value, we obtain the fuzzy basic reproduction number for groups of infected individuals with different virus loads. Further, a basic reproduction number for the classical and the fuzzy model are compared. Finally, a program based on the basic reproduction value of disease control is suggested and the numerical simulations are carried out to illustrate the analytical results
Ecological system with fear induced group defence and prey refuge
In this study, we investigate the dynamics of a spatial and non spatial
prey-predator interaction model that includes the following: (i) fear effect
incorporated in prey birth rate; (ii) group defence of prey against predators;
and (iii) prey refuge. We provide comprehensive mathematical analysis of
extinction and persistence scenarios for both prey and predator species. To
better explore the dynamics of the system, a thorough investigation of
bifurcation analysis has been performed using fear level, prey birth rate, and
prey death rate caused by intra-prey competition as bifurcation parameter. All
potential occurrences of bi-stability dynamics have also been investigated for
some relevant sets of parametric values. Our numerical evaluations show that
high levels of fear can stabilize the prey-predator system by ruling out the
possibility of periodic solutions. Also, our model Hopf bifurcation is
subcritical in contrast to traditional prey-predator models, which ignore the
cost of fear and have supercritical Hopf bifurcations in general. In contrast
to the general trend, predator species go extinct at higher values of prey
birth rates. We have also found that, contrary to the typical tendency for prey
species to go extinct, both prey and predator populations may coexist in the
system as intra-prey competition level grows noticeably. The stability and
Turing instability of associated spatial model have also been investigated
analytically. We also perform the numerical simulation to observe the effect of
different parameters on the density distribution of species. Different types of
spatiotemporal patterns like spot, mixture of spots and stripes have been
observed via variation of time evolution, diffusion coefficient of predator
population, level of fear factor and prey refuge. The fear level parameter (k)
has a great impact on the spatial dynamics of model system
BODIPY-based fluorescent probes for sensing protein surface-hydrophobicity
Mapping surface hydrophobic interactions in proteins is key to understanding molecular recognition, biological functions, and is central to many protein misfolding diseases. Herein, we report synthesis and application of new BODIPY-based hydrophobic sensors (HPsensors) that are stable and highly fluorescent for pH values ranging from 7.0 to 9.0. Surface hydrophobic measurements of proteins (BSA, apomyoglobin, and myoglobin) by these HPsensors display much stronger signal compared to 8-anilino-1-naphthalene sulfonic acid (ANS), a commonly used hydrophobic probe; HPsensors show a 10- to 60-fold increase in signal strength for the BSA protein with affinity in the nanomolar range. This suggests that these HPsensors can be used as a sensitive indicator of protein surface hydrophobicity. A first principle approach is used to identify the molecular level mechanism for the substantial increase in the fluorescence signal strength. Our results show that conformational change and increased molecular rigidity of the dye due to its hydrophobic interaction with protein lead to fluorescence enhancement
Biofuels for Defence Use: Past, Present And Future
Defence sector desires to attain energy self-sufficiency and security. In recent years, emergence of biofuel as an alternative source has raised the hopes of Defence. Ethanol and bio-diesel are currently being used as blends in different parts of the world. While, bio-diesel is mostly being blended in 2-20% in different parts of the world, ethanol blending has reached upto 85%. Owing to the sustainability reasons, the choice of feedstock for ethanol production is gradually changing from corn to lignocelluloses biomass. Jatropha curcas, is still the choice feedstockfor bio-diesel in most third world countries. This institute has put in rigrous efforts to identify high yielding varieties of Jatropha, improving its yield, standardizing trans-esterification to obtain high quality bio-diesel and its trials and testing in various vehicles and equipment. Second generation biofuels using biomass such as farm and forest wastes as feedstocks are promising in terms of their overall sustainability and volume produced. They can be used as drop in fuels. However, time is required to utilize their potential fully. Algae, the third generation biofuel feedstock still needs extensive R&D to make it economically sustainable. Whatever, the technology used, defence forces will accept any biofuel, which should be available constantly and priced below the existing petroleum fuels. The scope of producing by-products and finding a lucarative market for these products can ensure that prices ofbiofuels remain lower than the petroleum fuel
The clinical characteristics, etiologic pathogens and the risk factors associated with dehydration status among under-five children hospitalized with acute diarrhea in Savannakhet Province, Lao PDR
Background:Acute diarrhea is a common health problem in children, especially those under five years of age (U5). The mortality rate due to acute diarrhea among U5 children accounted for 11% in Lao PDR in 2016. No study has been done to investigate the etiologic pathogens of acute diarrhea and the risk factors associated with dehydration status among U5 children hospitalized with acute diarrhea in this region.Objectives:The study aimed to evaluate the clinical characteristics, etiological agents and associated factors of dehydration status of acute diarrhea among hospitalized U5 children in Savannakhet Province, Lao PDR.Methods:This retrospective study reviewed paper-based medical records with available stool examination results of 33 U5 children hospitalized with acute diarrhea in Savannakhet Provincial Hospital, Lao PDR between Jan. 2018 and Dec. 2019. Descriptive statistics were used to describe clinical characteristics and etiologic agents of acute diarrhea of the children. Nonparametric test, Pearson’s Chi-square test and Fisher exact test were used to determine the risk factors associated with level of dehydration of the participants.Results:Vomiting was the most common symptom (66.6%), followed by fever (60.6%). Dehydration was found in 48.4% of subjects. Rotavirus was the most common identified pathogen with a prevalence of 55.5%. Bacterial enteric infection was identified in 15.1% of patients. There is a significantly higher prevalence of dehydration among children with acute diarrhea caused by rotavirus compared to those with negative rotavirus testing (70.0% vs. 12.5%, p = 0.02).Conclusions:Rotavirus was the most prevalent pathogen of acute diarrhea among U5 children. Pediatric patients with acute diarrhea caused by rotavirus had a higher prevalence of dehydration compared to those with negative rotavirus testing
THE FIRST REPORT OF A POSSIBLE SARS-CoV-2 REINFECTION IN NEPAL
oai:ojs2.jebas.org:article/1Since August 2020, a growing number of confirmed SARS-CoV-2 cases, after approximately three months, in most of them, again presented a new infection episode, which has been defined as reinfection. So far, no cases have been reported in Nepal, and still there is limited the number of them, especially of those fully confirmed. Here, we report a case and discuss its multiple implications in the ongoing COVID-19 pandemic
Cerebrovascular dysfunction with stress and depression
Maintenance of adequate tissue perfusion through a dense network of cerebral microvessels is critical for the perseveration of normal brain function. Regulation of the cerebral blood flow has to ensure adequate delivery of nutrients and oxygen with moment-to-moment adjustments to avoid both hypo- and hyper-perfusion of the brain tissue. Even mild impairments of cerebral blood flow regulation can have significant implications on brain function. Evidence suggests that chronic stress and depression elicits multifaceted functional impairments to the cerebral microcirculation, which plays a critical role in brain health and the pathogenesis of stress-related cognitive impairment and cerebrovascular events. Identifying the functional and structural changes to the brain that are induced by stress is crucial for achieving a realistic understanding of how related illnesses, which are highly disabling and with a large economic cost, can be managed or reversed. This overview discusses the stress-induced alterations in neurovascular coupling with specific attention to cerebrovascular regulation (endothelial dependent and independent vasomotor function, microvessel density). The pathophysiological consequences of cerebral microvascular dysfunction with stress and depression are explored
Early centralized isolation strategy for all confirmed cases of COVID-19 remains a core intervention to disrupt the pandemic spreading significantly
Background: In response to the spread of the coronavirus disease 2019 (COVID-19), plenty of control measures were proposed. To assess the impact of current control measures on the number of new case indices 14 countries with the highest confirmed cases, highest mortality rate, and having a close relationship with the outbreak’s origin; were selected and analyzed.Methods: In the study, we analyzed the impact of five control measures, including centralized isolation of all confirmed cases, closure of schools, closure of public areas, closure of cities, and closure of borders of the 14 targeted countries according to their timing; by comparing its absolute effect average, its absolute effect cumulative, and its relative effect average.Results: Our analysis determined that early centralized isolation of all confirmed cases was represented as a core intervention in significantly disrupting the pandemic’s spread. This strategy helped in successfully controlling the early stage of the outbreak when the total number of cases were under 100, without the requirement of the closure of cities and public areas, which would impose a negative impact on the society and its economy. However, when the number of cases increased with the apparition of new clusters, coordination between centralized isolation and non-pharmaceutical interventions facilitated control of the crisis efficiently.Conclusion: Early centralized isolation of all confirmed cases should be implemented at the time of the first detected infectious case
The relationship between microstructure and photocatalytic behavior in lanthanum-modified 2D TiO2 nanosheets upon annealing of a freeze-cast precursor
Titanium dioxide modified with 3 wt% La was prepared via a green freeze-casting method, and its photocatalytic activity was tested in terms of its ability to degrade 4-chlorophenol (4-CP) and remove total organic carbon (TOC). Under annealing conditions, the freeze-cast precursor was transformed into an La-modified anatase with a well-defined 2D TiO(2) nanosheet morphology. Rietveld refinement of the X-ray diffraction patterns confirmed the substitutional nature of the La cation that induced local structural variations and involved subtle ion displacement in the TiO(2) lattice due to the ionic size effect. Despite nearly identical tetragonal structures, replacement of Ti with La alters the photocatalytic activity through a reduction in band gap energies and an increase in charge carrier mobility. Material annealed at 650 °C exhibited the highest photocatalytic performance and achieved efficient TOC removal. Upon annealing at 800 °C, nanoscale lanthanum-enriched regions were generated due to the diffusive migration of La cations and phase transition from anatase to rutile. The La(3+) cation, acting as a structural promoter, supported 2D TiO(2) growth with well controlled crystallite size, surface area and porosity. La(3+) could be regarded as a potential electronic promoter that can reduce the band gap of 2D TiO(2) nanosheets and can provide a signature of the electron transfer and carrier charge separation. Both methods, kinetics of degradation of 4-CP and TOC, provided similar results, revealing that the photocatalytic activity under UV light irradiation increased in the order 950C < 500 °C < 800 °C < 650 °C < TiO(2)-P25
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