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•The nZVI@GTBC biochar is prepared and used for lead immobilization studies.•The polyphenol content of green tea influence the particle size of nZVI.•The nZVI@GTBC biochar exhibits ...higher stability as compared with bare GTBC biochar.•Sequential extraction procedure study was carried out.
Biochar-based nanocomposites with functional materials provide an excellent prospect in reactivity and stability. Most biochar reported have no reusability upon aging and offer the risk of release of immobilized components after short-term immobilization. To overcome this, we developed nano zero-valent iron (nZVI) impregnated magnetic green tea biochar (nZVI@GTBC) and studied its performance in immobilizing Pb and long-term effectiveness in the soil. The reactive nZVI units were obtained from iron oxide solution by reducing with polyphenol solution (green tea extract) and were successively stabilized by impregnation onto the remaining green tea waste matrix through co-precipitation technique. Finally, the magnetic biochar was developed from the above nZVI impregnated green tea waste through oven drying and slow pyrolysis technique in different temperature range (150–650 °C). The synthesized nZVI@GTBC biochar was characterized and studied by XRD, FTIR, Raman, UV–Vis, TG/DSC, XPS, SEM, and TEM. The nZVI@GTBC obtained with a particle size of 130 nm and surface charge of +2.8 C/m2 at 450 °C. Moreover, colloidal stability and mobility experiments were considered to explain the transport behavior and stability of bare nZVI and magnetic nZVI@GTBC in the soil. The immobilization of Pb by pristine nZVI, GTBC, and nZVI@GTBC was compared and explained under different soil pH conditions. The bioavailability of Pb content before and after immobilization was investigated through leaching experiments. Further, thirty days of soil incubation were carried out to examine different species of Pb according to the Tessier sequential extraction scheme. The study suggested that nZVI@GTBC enhanced the immobilization efficiency by 19.38% in comparison with pristine nZVI and 57.14% in comparison with bare GTBC biochar.
Mathematical models have been used to provide an explicit framework for understanding malaria transmission dynamics in human population for over 100 years. With the disease still thriving and ...threatening to be a major source of death and disability due to changed environmental and socio-economic conditions, it is necessary to make a critical assessment of the existing models, and study their evolution and efficacy in describing the host-parasite biology. In this article, starting from the basic Ross model, the key mathematical models and their underlying features, based on their specific contributions in the understanding of spread and transmission of malaria have been discussed. The first aim of this article is to develop, starting from the basic models, a hierarchical structure of a range of deterministic models of different levels of complexity. The second objective is to elaborate, using some of the representative mathematical models, the evolution of modelling strategies to describe malaria incidence by including the critical features of host-vector-parasite interactions. Emphasis is more on the evolution of the deterministic differential equation based epidemiological compartment models with a brief discussion on data based statistical models. In this comprehensive survey, the approach has been to summarize the modelling activity in this area so that it helps reach a wider range of researchers working on epidemiology, transmission, and other aspects of malaria. This may facilitate the mathematicians to further develop suitable models in this direction relevant to the present scenario, and help the biologists and public health personnel to adopt better understanding of the modelling strategies to control the disease.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
India's lockdown and subsequent restrictions against SARS-CoV-2, if lifted without any other mitigations in place, could risk a second wave of infection. A test-and-isolate strategy, using PCR ...diagnostic tests, could help to minimise the impact of this second wave. Meanwhile, population-level serological surveillance can provide valuable insights into the level of immunity in the population. Using a mathematical model, consistent with an Indian megacity, we examined how seroprevalence data could guide a test-and-isolate strategy, for fully lifting restrictions. For example, if seroprevalence is 20% of the population, we show that a testing strategy needs to identify symptomatic cases within 5-8 days of symptom onset, in order to prevent a resurgent wave from overwhelming hospital capacity in the city. This estimate is robust to uncertainty in the effectiveness of the lockdown, as well as in immune protection against reinfection. To set these results in their economic context, we estimate that the weekly cost of such a PCR-based testing programme would be less than 2.1% of the weekly economic loss due to the lockdown. Our results illustrate how PCR-based testing and serological surveillance can be combined to design evidence-based policies, for lifting lockdowns in Indian cities and elsewhere.
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•Combining o- aminothiophenol, salisaldehyde and rhodamine-B generates a probe (L). X-ray crystal structure of its precursor is presented.•L discriminates Al3+ and Hg2+ at nano-level ...by turning colorless L to green and red under UV light while they look pink and red at visible light.•CHEF assisted FRET process is responsible for Al3+ sensing whereas simple spirolactam ring opening is responsible for Hg2+ sensing.•Intracellular Hg2+ and Al3+ imaging in human breast cancer cells (MCF7) and their determination in real and sea fish samples.are performed.•L is useful to construct a binary logic gate with discrete output signal for potential unconventional computing systems.
Bringing o- aminothiophenol, salisaldehyde and rhodamine-B under an umbrella to link them chemically, an excellent probe (L) is designed, prepared and characterised to detect and discriminate Hg2+ and Al3+ using emission and absorption spectroscopy. In presence of Hg2+, L emits bright red color. The same color is observed in bare eye in visible light. On the other hand, Al3+ imparts green and pink colors under similar conditions. UV•vis and fluorescence titration, 1H NMR and fluorescence lifetime decay studies unveil the recognition event. Live cell imaging, sea fish and environmental sample analysis has also been performed.
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•Colloidal Mg(OH)2 was used for in situ immobilization of heavy metals.•Transport performance of colloidal Mg(OH)2 was enhanced by viscosity modification.•Colloidal Mg(OH)2 exhibits ...higher remediate capacity after viscosity modification.
Mg(OH)2 is extensively considered as an potential material for groundwater remediation because its injection could provide a long-term pH buffering system. In this study, colloidal Mg(OH)2 was regarded as an alternative reagent for the in-situ remediation of heavy metal polluted groundwater. However, experiments demonstrated that the transport performance of colloidal Mg(OH)2 in groundwater was depressed by the contamination of heavy metals and its stabilization performance for heavy metals was deteriorated. To solve these difficulties, the transport properties of colloidal Mg(OH)2 was enhanced by viscosity modification by adding xanthan gum (XG). Column tests were conducted to investigate the transport performance of colloidal Mg(OH)2 with and without viscosity modification, and to evaluate its stabilization effect for Pb and Cd polluted aquifer. Experimental results indicate that although the injection pressure increased during the migration of colloidal Mg(OH)2, the increased viscosity effectively could decrease the intensity of Brownian motion of Mg(OH)2 particles and reduce the collision efficiency between colloidal particles and aquifer media. Thus, deposition of Mg(OH)2 particles on aquifer media significantly reduced after viscosity modification, and its migration performance in groundwater was effectively enhanced. In contrast, the distribution of colloidal Mg(OH)2 was more uniform after viscosity modification, and immobilization of heavy metals in contaminated aquifer was noticeably improved, furthermore the exchangeable fraction of Pb and Cd is significantly reduced.
A novel hybrid material zirconium polyacrylamide (ZrPACM-43) was synthesized by mixing aqueous solution of zirconium oxychloride and mixture of acrylamide following an environmental friendly sol–gel ...method. The material was characterized by FTIR, XRD, TGA-DTA, and SEM-EDS. The extent of arsenic removal capacity was tested by the material by varying the solution parameters like adsorbent dose, adsorbate concentration, pH of the solution, contact time and temperature. The maximum removal efficiency of arsenic(III) was 98.22% under optimum conditions with adsorption equilibrium time of 120min. The adsorption process followed second order kinetics and adsorption data were best fitted to linearly transformed Freundlich isotherm with correlation coefficient of R2>0.999. Adsorption capacity (qo) calculated from Langmuir isotherm was found to be 41.48mgg−1. The thermodynamic parameter ΔH indicates an endothermic adsorption process. The regeneration study shows that the material is regenerated by 1M alkali solution.
Powders or cohesive granular materials are widely handled in industries. However, our understanding of the rheology of these materials is limited. Here, we provide a comprehensive analysis of the ...rheology of a cohesive granular medium, sheared in a normal-stress-imposed plane shear cell over a wide range of shear rate, employing numerical simulations. At high imposed shear rates, the flow is homogeneous, and the rheology is well described by the existing scaling laws, involving the inertial number and the “effective” cohesion number S. Mandal et al., Insights into the Rheology of Cohesive Granular Media, Proc. Natl. Acad. Sci. U.S.A. 117, 8366 (2020). However, at low imposed shear rates, the flow is inhomogeneous, exhibiting the coexistence of flowing and nonflowing regions in the material, popularly known as shear banding. We thoroughly analyze the crucial features of this shear-banded flow regime and discuss striking similarities between the shear banding for granular media and other complex fluids. We reveal that the occurrence of shear banding is related to the existence of a nonmonotonic intrinsic rheological curve and that increasing adhesion increases the nonmonotonicity and the tendency toward shear localization. A simple theoretical model based on a nonlocal rheological model coupled with a nonmonotonic flow curve is proposed and is shown to successfully reproduce all the key features of the shear banding observed in the numerical simulations. The results have important implications for the handling of powders in industries.
ObjectivesTo investigate the impact of targeted vaccination strategies on morbidity and mortality due to COVID-19, as well as on the incidence of SARS-CoV-2, in India.DesignMathematical ...modelling.SettingsIndian epidemic of COVID-19 and vulnerable population.Data sourcesCountry-specific and age-segregated pattern of social contact, case fatality rate and demographic data obtained from peer-reviewed literature and public domain.ModelAn age-structured dynamical model describing SARS-CoV-2 transmission in India incorporating uncertainty in natural history parameters was constructed.InterventionsComparison of different vaccine strategies by targeting priority groups such as keyworkers including healthcare professionals, individuals with comorbidities (24–60 years old) and all above 60.Main outcome measuresIncidence reduction and averted deaths in different scenarios, assuming that the current restrictions are fully lifted as vaccination is implemented.ResultsThe priority groups together account for about 18% of India’s population. An infection-preventing vaccine with 60% efficacy covering all these groups would reduce peak symptomatic incidence by 20.6% (95% uncertainty intervals (UI) 16.7–25.4) and cumulative mortality by 29.7% (95% CrI 25.8–33.8). A similar vaccine with ability to prevent symptoms (but not infection) will reduce peak incidence of symptomatic cases by 10.4% (95% CrI 8.4–13.0) and cumulative mortality by 32.9% (95% CrI 28.6–37.3). In the event of insufficient vaccine supply to cover all priority groups, model projections suggest that after keyworkers, vaccine strategy should prioritise all who are >60 and subsequently individuals with comorbidities. In settings with weakest transmission, such as sparsely populated rural areas, those with comorbidities should be prioritised after keyworkers.ConclusionsAn appropriately targeted vaccination strategy would witness substantial mitigation of impact of COVID-19 in a country like India with wide heterogeneity. ‘Smart vaccination’, based on public health considerations, rather than mass vaccination, appears prudent.
Background: Measurements TB incidence and mortality are crucial for monitoring progress towards SDG goals for TB. Until recently, WHO estimated TB burden in India with applied simple, transparent ...equilibrium models to data from Gujarat, an Indian state where the first state-level prevalence survey was conducted in 2011. However, since then there has been several interventions in India including national TB prevalence survey, infection survey, sub-national survey & certification which gives opportunity for national and sub-national estimates for TB incidence and mortality. Methods: We developed a model is a compartmental, deterministic framework, taking account of TB natural history, as well as India's healthcare system including health care seeking from public and private sector. To address changes in TB burden owing to COVID disruptions, we followed same model that used by WHO in the global TB Report 2022 with additional impact of delta wave in 2021. Major sources of data included National TB Prevalence survey, trends in caseloads in public and private sector including their contribution and mortality information. Results: We estimated total TB incidence of 2.77 million in the year 2022 as against 2.97 in the year 2015 and corresponding TB mortality of 0.32 and 0.36 million respectively. In terms of rate per 1,00,000 TB incidence in 2022 was 196 as compared to 225 in the year 2015 and mortality was 23 and 27 respectively. TB incidence estimates are similar to what was estimated by WHO, while mortality estimates appear different in our estimates due to different calibration targets depending on in-country published data. Conclusion: Even if TB burden is infeasible to measure directly, a range of data can nonetheless offer indirect evidence for its estimation: mathematical modelling can be a helpful tool for bringing together these diverse sources of evidence, and deriving estimates that are consistent with them all. While the RGI reported mortality is an important source of information, its quality and coverage for medically certified cause of deaths requires improvement in India.
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