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Polycrystalline Mg2Si thin films of varying thickness were grown on (100) Si substrate by employing extensive surface diffusion of elemental atoms. At first, magnesium atoms were deposited on (100) Si substrate with the aid of radio frequency magnetron sputtering; in order to promote interdiffusion of Mg and Si, annealing was carried out in hydrogen atmosphere at the temperature of 500 °C for a period of four hours. Films of thickness values 500 nm and 100 nm were prepared for further study. Electrical transport behaviour of thin films was studied by measuring Hall conductivity, charge carrier concentration and its mobility. Moreover, current-voltage characteristics of Mg2Si thin films were studied by four probe colinear method. Structural analysis was done through X-ray diffraction study; microstructural study was conducted in SEM. While X-ray Photoelectron Spectroscopy (XPS) was used for securing chemical information of the film surface, Energy Dispersive Spectroscopy (EDS) was also employed to know the elemental composition of Mg2Si thin films. Further, Atomoic Force microscopy (AFM) was conducted for topographic study. It was found that the Mg2Si thin films prepared in the present investigation behaved as degenerate semiconductor with the maximum attainable conductivity of in the range of 102 S/m. Further, it was observed that the conductivity of higher thickness Mg2Si thin film(~ 1000 nm) was lower than that of lower thickness film (~ 500 nm) at all the test temperature. [ABSTRACT FROM AUTHOR]

To Background: Obesity is a global epidemic and is associated with cognitive impairment and dementia. It remains unknown whether weight loss interventions, such as bariatric surgery, can mitigate cognitive impairment. Objectives: We aimed to determine the effect of surgical weight loss on cognition in individuals with class II/III obesity. Design: We performed a prospective cohort study of participants who underwent bariatric surgery. At baseline and two years following surgery, participants completed metabolic risk factor and neuropsychological assessments. Setting: Participants were enrolled from an academic suburban bariatric surgery clinic. Participants: There were 113 participants who completed baseline assessments and 87 completed two-year follow-up assessments (66 in-person and 21 virtual) after bariatric surgery. The mean (SD) age was 46.8 (12.5) years and 64 (73.6%) were female. Intervention: Bariatric surgery. There were 77 (88.5%) participants that underwent sleeve gastrectomy and 10 (11.5%) that underwent gastric bypass surgery. Measurements: Cognition was assessed using the NIH toolbox cognitive battery (NIHTB-CB) and the Rey Auditory Verbal Learning Test (AVLT). The primary outcome was the change in NIHTB-CB fluid composite score before and after surgery. Results: The primary outcome, NIHTB-CB composite score, was stable following bariatric surgery (−0.4 (13.9), p=0.81,n=66). Among secondary outcomes, the NIHTB-CB dimensional card sorting test (executive function assessment), improved (+6.5 (19.9), p=0.01, n=66) while the Rey AVLT delayed recall test (memory assessment) declined (−0.24 (0.83), p=0.01, n=87) following surgery. Improvements to metabolic risk factors and diabetes complications were not associated with improvements to NIHTB-CB composite score. The other 4 NIHTB-CB subtests and Rey AVLT assessments of auditory learning and recognition were stable at follow-up. Conclusions: Following bariatric surgery, the age-adjusted composite cognitive outcome did not change, but an executive subtest score improved. These results suggest that bariatric surgery may mitigate the natural history of cognitive decline in individuals with obesity, which is expected to be faster than normal aging, but confirmatory randomized controlled trials are needed. The decline in delayed recall also warrants further studies to determine potential differential effects on cognitive subtests. [ABSTRACT FROM AUTHOR]

This paper reports the results of a study on the effect of N-ion implantation on structure and properties of Magnesium Silicide (Mg2Si) thin film that is known to be a potential thermoelectric (TE) material. Mg2Si thin films of thickness 300 nm have been deposited on the silicon (100) substrate at room temperature using the sputtering technique. The thin films have been subjected to 50 keV N-ion implantation under various fluence values ranging from 5 × 1014 to 1 × 1016 ions/cm2. Structural characterization by X-ray Diffraction (XRD) technique has verified that the pristine thin film is constituted by a crystalline single phase Mg2Si material; however, ion irradiation leads to partial amorphization of the Mg2Si thin film. Field–Emission Scanning Electron Microscopy (FE-SEM) with Energy Dispersive Spectroscopy (EDS) is employed to obtain microstructural and compositional information. While particle coarsening due to ion implantation is affirmed by FESEM observation, the EDS study cannot authenticate the exact stoichiometry of the film due to substrate effect. X-ray Photoelectron Spectroscopy (XPS) study was conducted to secure information about the chemical state of the elements at the film surface which confirms the presence of Mg2Si phase in the pristine film; and of both Mg2Si and nitrogen in the implanted thin films. The electrical transport behavior of Mg2Si thin films have been studied by way of I-V and Hall measurements; the conductivity values are found to increase from 6*102 S/m to 1.17*103 S/m as the fluence is raised from 5 × 1014 to 1 × 1016 ions/cm2 at a temperature of 150 °C. The electrical conductivities of all the samples are seen to increase continuously with increasing temperature thereby, showing semiconducting behavior of the thin films. [ABSTRACT FROM AUTHOR]

Ni nanoparticles layer of nominal thickness in the range of 5–40 nm were deposited on polyvinyl alcohol (PVA) film by using the ion beam sputtering (IBS) technique. PVA films were made on a quartz substrate by the solution casting technique. Grazing incidence X-ray diffraction (GIXRD) results reveal Ni is present in a metallic form in the FCC phase. AFM shows that roughness increases with increase in thickness of Ni layer and corresponding MFM images of magnetic domains were recorded. Soft X-ray absorption spectroscopy (SXAS) studies on the PVA/Ni nanocomposites films were recorded using synchrotron radiation. This study is used to study the electronic structure of the as-prepared nanocomposite films and reveals that Ni nanoparticles are present in their metallic form. Magnetic properties were measured using the magneto-optical Kerr effect (MOKE) magnetometer and the films were found to be magnetically soft with higher value of coercivity at lower thickness of Ni nanoparticles layer. The results of magnetic studies are discussed in light of the microstructure and morphological features of PVA/Ni nanocomposite films. The PVA/Ni nanocomposites showed interesting anisotropic magnetic behavior; thus the investigative results may be useful for the development of futuristic flexible functional magnetic material system. [ABSTRACT FROM AUTHOR]

Silver telluride (Ag2Te) thin films of thickness ranging from 25 to 150 nm have been prepared by thermal evaporation technique. Deposition of Ag2Te thin films is accomplished at 1075 K, on an ultra-clean glass substrate, kept within a resistive heating thermal evaporator under a pressure of less than 10–5 mbar. X-ray diffraction (XRD) study, scanning electron microscopy (SEM), energy-dispersive microanalysis (EDAX) and UV spectroscopy are employed for structural, chemical and optical property characterisation. XRD observation suggests that silver telluride thin films become completely crystalline beyond a 100 nm film thickness. Films of lower thickness resemble amorphous structure. Both XRD and SEM results demonstrate that partial decomposition of Ag2Te has taken place during thermal evaporation. SEM study confirms that the surface of synthesised thin films is quite smooth. The results of UV spectroscopy establish that the band gap of Ag2Te thin films lies within 1.4–1.7 eV. High absorption coefficient in UV region confirms that the Ag2Te thin films exhibit direct band transition. Moreover, the optical band gap of thermally evaporated Ag2Te thin films varies with the thickness of the thin films. I–V characteristics study demonstrates that silver telluride thin films are highly conducting in the presence of light and is supposedly a good candidate material for solar cell application. [ABSTRACT FROM AUTHOR]

This paper presents the structural and magnetic properties of polyvinyl alcohol/iron (PVA/Fe) nanocomposite films. Iron (Fe) films of different thicknesses were deposited on a PVA substrate using ion beam sputtering. The Fe nanoparticle layer thickness ranges from 3 to 50 nm on the PVA substrate. Grazing incidence x-ray diffraction has been carried out to study the structural behavior of the prepared films. An atomic force microscope records the indicated remarkable change in the roughness of the nanocomposite film as a result of initiation of vertical growth of sputtered Fe nanoparticles.Magneto-optic Kerr effect (MOKE) magnetometry and MOKE spectroscopy have been employed to evaluate the magnetic property and simultaneously study the real time growth of the magnetic domain structure for both 0° and 90° azimuthal angles. MOKE microscopic images indicated the magnetization reversal commensurate with the hysteresis loop of the nanocomposites. All the films show soft ferromagnetic behavior. Gradual development of the domain structure is observed in the MOKE micrograph with the increase in the thickness of Fe nanoparticle deposition. Ex situ magnetic force micrographs of the magnetic domain structures supported the observation of MOKE microscopic studies, which indicated switching of in-plane magnetization to out-of-plane magnetization near an Fe nanoparticle deposition thickness of 40 nm. The PVA matrix appears to be an effective material to support the growth of magnetic properties in the PVA/Fe nanocomposite system. The evolution of Fe nanostructures on PVA and the resulting magnetic behavior have been discussed. [ABSTRACT FROM AUTHOR]

In this research work, environmental monitoring processes and assessments are carried out by the modeling and analysis of the water quality of the Chambal River in the state of Rajasthan. Various samples were collected from different locations along the course of the river flow. This water is used for different kinds of human, animal, and agriculture corp. activities. Comparative analyses were conducted on the water parameters, viz. biochemical oxygen demand, chemical oxygen demand, dissolved oxygen, total coliform, and conductivity, for the of consecutive years 2020 and 2021. A model was developed with the help of MATLAB Simulink software (Version R2019a) to find the causes of oxygen deficiency and reoxygenation in water with time and distance. The results of two consecutive years help to predict the responsible factors for the degradation of the river's water quality. The water quality modeling and simulation results conclude that the water quality of the Chambal River flowing through Rajasthan can rejuvenate itself during an alarming oxygen deficit within a short period. According to the results of this study, the concentration of dissolved oxygen in the water of the Chambal River is high enough to support the survival of the endangered species that inhabit the area. [ABSTRACT FROM AUTHOR]

Evolution of structure and properties in ternary Ag2Te1−xSex (x~0.3) alloy is examined in the present paper. Stoichiometric quantity of pure powders of Ag2Te and Ag2Se was mixed in a ball mill and then melted at high temperature, 1025°C in a vacuum sealed quartz tube, followed by annealing at 700°C for 12 hours. Thin films of Ag2Te.7Se.3 of different thickness viz.25, 50, 100, and 150 nm are produced by thermal evaporation method. Thermal evaporation method is carried out by resistive heating of the solid of Ag2Te.7Se.3 sample at 1000°C under a high vacuum (pressure in the chamber is less than 10−5 mbar). The thin films were subjected to structural analysis by XRD, microstructural study by scanning electron microscopy and optical property study by UV-Vis. spectroscopy. It is found that Ag2Te1−xSex (x~0.3) is formed by alloying of two solid solutions, of which one is based on Ag2Te with Se as solute and the other is Ag2Se-based solid solution in which Te is the solute. The peak position of Ag2Te-based solid solution is shifted toward higher angle whereas a reverse trend is observed in Ag2Se-based solution. The microstructure is composed of a solid solution of Ag2Te and Ag2Se along with the fine dispersion of elemental silver, tellurium and selenium. The optical band gap varies within 1.4 to 2.2 eV over the thickness range from 25 to 150 nm. The band gap initially increases with the film thickness, and beyond 50 nm, the band gap continuously decreases to 1.7 eV. The transmittance is lower for higher film thickness; while transmittance increases with wavelength, the rate of increase is enhanced in the infrared region. The absorption coefficient of thin films of Ag2Te.7Se.3 is as high as of the order of 105 cm−1. [ABSTRACT FROM AUTHOR]

Purpose: Postoperative spotting is a frequent adverse symptom after laparoscopic supracervical hysterectomy (LSH). The conical excision (eLSH) reduces the postoperative spotting rate, but data in a larger collective are still rare and inconsistent. The influence of persistent bleeding on the anxious and depressive symptoms has not been analyzed yet. Methods: 311 patients, who underwent a laparoscopic supracervical hysterectomy with conical excision (n = 163), or with straight cervical resection (n = 148) were included. Anxious and depressive symptoms and postoperative spotting were recorded before operation, at 3 month follow-up and at 1 year follow-up in both operative groups using a validated questionnaire (German version of Hospital Anxiety and Depression Scale, HADS-D) and additional questions concerning the frequency and impact of bleeding. Statistical analysis included the impairment of bleeding as well as its impact on depressive and anxious symptoms for both groups. Results: 11.5% after eLSH and 15.5% after LSH reported spotting after 1 year. Supracervical hysterectomy significantly improves depressive and anxious symptoms at 3 and at 12 month follow-up for both groups (p < 0.001) independent on residual spotting. Patients with a preoperative continuous bleeding showed a maximum benefit independent on operative method. Conclusion: Laparoscopic supracervical hysterectomy has a positive effect on anxious and depressive symptoms in the short-term and intermediate-term follow-up. The conical excision of the cervical stump reduces postoperative spotting rate, but has no explicit advantage on symptoms of depression or anxiety, irrespective of residual postoperative spotting. [ABSTRACT FROM AUTHOR]

Nonlocal reaction–diffusion equations describe various biological and biomedical applications. Their mathematical properties are essentially different in comparison with the local equations, and this difference can lead to important biological implications. This review will present the state of the art in the investigation of nonlocal reaction–diffusion models in biomedical applications. We will consider various models arising in mathematical immunology, neuroscience, cancer modelling, and we will discuss their mathematical properties, nonlinear dynamics, resulting spatiotemporal patterns and biological significance. [ABSTRACT FROM AUTHOR]

Thin film-based thermoelectric materials have attracted enormous research interest due to their potential to exhibit excellent thermoelectric (TE) behavior. Considering the potential of earth-abundant and nontoxic magnesium silicide (Mg2Si) to behave as a mid-temperature TE material, the present study was conducted to assess the structural evolution and electrical behavior of Mg2Si films prepared by electron beam thin film deposition technique. The films were deposited on silicon (100) substrate at room temperature with thickness ranging from 0.5 µm to 4 µm. The investigation revealed that the electrical behavior of this alloy film is considerably influenced by its thickness. The effect of film thickness on evolution of the structure was also studied by x-ray diffraction (XRD), field emission scanning electron microscopy, atomic force microscopy, and Raman spectroscopy. It was observed that the present experimentation could produce a nanocrystalline grain structure of Mg2Si alloy with a small quantity of excess magnesium phase. Moreover, XRD results delineated that the crystallite size is influenced by the thickness of the film under the same deposition conditions. The residual stress within the e-beam-deposited film, as manifested through the measured strain values of the films, was found to be thickness-dependent. Moreover, it was confirmed that there was no influence of the substrate on the structure and properties of the studied films. [ABSTRACT FROM AUTHOR]

Purpose: Supracervical as well as total hysterectomy are considered to improve postoperative sexuality as well as quality of life, but the benefit of supracervical hysterectomy (LSH) is impaired in up to 20 percent by postoperative spotting. The aim of this study was to analyze the influence of a conical excision of the cervical stump during supracervical hysterectomy on the postoperative spotting rate and its influence on sexuality and in turn quality of life.Methods: 321 Patients who underwent a laparoscopic supracervical hysterectomy with conical excision (extended laparoscopic supracervical hysterectomy, eLSH, n = 166, Dormagen hospital) or with straight cervical resection (laparoscopic supracervical hysterectomy, LSH, n = 133, MIC Clinics Berlin) were included. Sexual matters, quality of life parameters and additional questions were recorded before operation, at three months of follow up, and at one year of follow up in both groups using a validated questionnaire (German version of International Consultation on Incontinence Questionnaire Vaginal Symptoms Module, ICIQ_VS). Statistical analysis included the impact and impairment of bleeding on sexuality, quality of life in both groups and co-factors such as vaginal symptoms.Results: 11.3% after eLSH and 15.5% after LSH reported spotting after 1 year. Supracervical hysterectomy significantly improves quality of life and sexuality and a conical excision of the remaining stump is associated with a lower but insignificantly reduced spotting rates. Postoperative spotting has no negative influence on sexual matter score of ICIQ_VS, but reduces the postoperative quality of life focusing on vaginal symptoms in a significant way.Conclusion: The improvement of ICIQ_VS scores after supracervical hysterectomy is independent of postoperative spotting, but the quality-of-life score is positively influenced by a reduction in the postoperative spotting rate. [ABSTRACT FROM AUTHOR]

Summary: In this meta-analysis, we analyzed 7 observational studies for assessing the fracture risk in patients with hypoparathyroidism (hypoPT). We found that the risk of vertebral fractures is increased by almost 2-fold, especially those with nonsurgical hypoPT. Purpose: Patients with hypoPT have higher bone mineral density than age- and sex-matched controls. This would theoretically translate into a lower risk of fractures, although available clinical evidence is contradictory. Hence, the present systematic review and meta-analysis was undertaken to collate and provide a precise summary of fracture risk in hypoPT. Methods: PubMed, Scopus, and Web of Science databases were systematically searched using appropriate keywords till March 8, 2021, to identify observational studies reporting the rate of occurrence of fractures among hypoPT patients (nonsurgical and/or postsurgical) compared to non-hypoPT subjects (controls). Study quality was assessed using Newcastle-Ottawa Scale. Pooled odds ratio (OR) with 95% confidence intervals (CI) was calculated. Subgroup analyses of nonsurgical and postsurgical hypoPT patients were also conducted. Results: We identified 7 observational studies of high-quality pooling data retrieved from 1470 patients with hypoPT. When stratified based on the skeletal site, pooled analyses showed that hypoPT patients were at an increased risk of vertebral fractures compared to non-hypoPT controls (OR 2.22, 95% CI: 1.23, 4.03, p = 0.009, I2 = 49%, random-effects model). The increased risk of vertebral fractures was seen only in patients with nonsurgical hypoPT (OR 2.31, 95% CI: 1.32, 4.03, p = 0.003, I2 = 3%, random-effects model) but not in those with postsurgical hypoPT. hypoPT patients were not at an increased or decreased risk of any, humerus, or proximal femur/hip fractures than controls. Conclusions: Nonsurgical hypoPT patients are at an almost 2-fold increased risk of vertebral fractures and thus need to be actively screened irrespective of the underlying BMD. [ABSTRACT FROM AUTHOR]

The pristine poly(vinyl alcohol) and CuS nanoparticles with different concentrations (1 %-10 %) doped PVA films were prepared by solution casting method. The CuS nanoparticles were prepared by chemical precipitation; and XRD studies confirmed the formation of pure CuS nanoparticles with average size of 18 nm. The optical properties of pristine as well as doped PVA films were evaluated using UV-VIS-NIR spectroscopy. UV-VIS-NIR spectrum of CuS nanoparticles showed LSPR band in NIR region. The optical properties like absorption coefficient, bandgaps, high frequency refractive index, and metallization criterion have been evaluated; both the direct and indirect band gaps decreased in case of doped PVA films; and the results and the features are discussed. [ABSTRACT FROM AUTHOR]

This study looks at the dynamics of a Covid-19 type epidemic with a dual purpose. The first objective is to propose a reliable temporal mathematical model, based on real data and integrating the course of illness. It is a daily discrete model with different delay times, and whose parameters are calibrated from the main indicators of the epidemic. The model can be broken down in two decoupled versions: a mortality-mortality version, which can be used with the data on the number of deaths, and an infection-infection version to be used when reliable estimates of infection rate are available. The model allows to describe realistically the evolution of the main markers of the epidemic. In addition, in terms of deaths and occupied ICU beds, the model is not very sensitive to the current uncertainties about IFR. The second objective is to study several original scenarios for the epidemic's evolution, especially after the period of strict lockdown. A coherent strategy is therefore proposed to contain the outbreak and exit lockdown, without going into the risky herd immunity approach. This strategy, called zigzag strategy, is based on a classification of the interventions into four lanes, distinguished by a marker called the daily reproduction number. The model and strategy in question are flexible and easily adaptable to new developments such as mass screenings or infection surveys. They can also be used at different geographical scales (local, regional or national). [ABSTRACT FROM AUTHOR]

This study aims to establish a model-based framework for inferring key transmission characteristics of the newly emerging outbreak of the coronavirus disease 2019 (COVID-19), especially the epidemic dynamics under quarantine conditions. Inspired by the shifting therapeutic levels and capacity at different stages of the COVID-19 pandemic, we propose a modified SEIR model with a two-phase removal rate of quarantined hosts undergoing continuously tunable transition. We employ the Markov Chain Monte Carlo (MCMC) approach for inferring and forecasting the epidemiological dynamics from the publicly available surveillance reports. The effectiveness of a short-term prediction is illustrated by adopting the data sets from 10 demographic regions including Chinese mainland and South Korea. In the surveillance period, the average R0 $\mathcal{R}_0$ R 0 ranges from 1.74 to 3.28, and the median of the mean latent period does not exceed 10 days across the surveillance regions. [ABSTRACT FROM AUTHOR]

The work is devoted to the analysis of cell population dynamics where cells make a choice between differentiation and apoptosis. This choice is based on the values of intracellular proteins whose concentrations are described by a system of ordinary differential equations with bistable dynamics. Intracellular regulation and cell fate are controlled by the extracellular regulation through the number of differentiated cells. It is shown that the total cell number necessarily oscillates if the initial condition in the intracellular regulation is fixed. These oscillations can be suppressed if the initial condition is a random variable with a sufficiently large variation. Thus, the result of the work suggests a possible answer to the question about the role of stochasticity in the intracellular regulation. [ABSTRACT FROM AUTHOR]

Coronavirus disease 2019 (COVID-19) poses a great threat to public health and the economy worldwide. Currently, COVID-19 evolves in many countries to a second stage, characterized by the need for the liberation of the economy and relaxation of the human psychological effects. To this end, numerous countries decided to implement adequate deconfinement strategies. After the first prolongation of the established confinement, Morocco moves to the deconfinement stage on May 20, 2020. The relevant question concerns the impact on the COVID-19 propagation by considering an additional degree of realism related to stochastic noises due to the effectiveness level of the adapted measures. In this paper, we propose a delayed stochastic mathematical model to predict the epidemiological trend of COVID-19 in Morocco after the deconfinement. To ensure the well-posedness of the model, we prove the existence and uniqueness of a positive solution. Based on the large number theorem for martingales, we discuss the extinction of the disease under an appropriate threshold parameter. Moreover, numerical simulations are performed in order to test the efficiency of the deconfinement strategies chosen by the Moroccan authorities to help the policy makers and public health administration to make suitable decisions in the near future. [ABSTRACT FROM AUTHOR]

We propose a model for the COVID-19 epidemic where the population is partitioned into classes corresponding to ages (that remain constant during the epidemic). The main feature is to take into account the infection age of the infected population. This allows to better simulate the infection propagation that crucially depend on the infection age. We discuss how to estimate the coefficients from data available in the future, and introduce a confinement variable as control. The cost function is a compromise between a confinement term, the hospitalization peak and the death toll. Our numerical experiments allow to evaluate the interest of confinement varying with age classes. [ABSTRACT FROM AUTHOR]

Cancer cervix is diagnosed late in women due to anatomical inaccessibility of the area. Hence, a robust screening strategy will help detect carcinoma cervix early which will significantly decrease the mortality and morbidity due to this disease. We evaluated DNA methylation of three tumour suppressor genes p15, p16 and E-Cadherin on cervical smears to assess DNA methylation as a screening tool for detection of early cervical cancer in comparison to PAP smears. DNA was extracted from cervical smears of 20 cases and 30 controls. The DNA was bisulphite modified. Methylation specific PCR (MSP) was performed to assess the methylation status of the promoter region of each of the genes. MSP results were compared with PAP smears to assess the utility of DNA methylation of these genes in screening for cervical cancer. DNA methylation was detected in 55% subjects in p15 gene, 45% in p16 gene and 40% in E-Cadherin gene. This was statistically significant when compared to the controls. DNA methylation of E-Cadherin, and p15 genes as a panel has a sensitivity and specificity of 80% and 90% respectively, which is better than the sensitivity of PAP smear for detection of early cancer cervix. Increased DNA methylation is seen in p15, p16 and E-Cadherin genes in early cancer cervix. p15 and E-Cadherin in combination can be used as a screening tool for detection of early cancer cervix. [ABSTRACT FROM AUTHOR]

Attempts to curb the spread of coronavirus by introducing strict quarantine measures apparently have different effect in different countries: while the number of new cases has reportedly decreased in China and South Korea, it still exhibit significant growth in Italy and other countries across Europe. In this brief note, we endeavour to assess the efficiency of quarantine measures by means of mathematical modelling. Instead of the classical SIR model, we introduce a new model of infection progression under the assumption that all infected individual are isolated after the incubation period in such a way that they cannot infect other people. Disease progression in this model is determined by the basic reproduction number R0 $\mathcal{R}_0$ R 0 (the number of newly infected individuals during the incubation period), which is different compared to that for the standard SIR model. If R0 > 1 $\mathcal{R}_0 >1$ R 0 > 1 , then the number of latently infected individuals exponentially grows. However, if R0 < 1 $\mathcal{R}_0 R 0 < 1 (e.g. due to quarantine measures and contact restrictions imposed by public authorities), then the number of infected decays exponentially. We then consider the available data on the disease development in different countries to show that there are three possible patterns: growth dynamics, growth-decays dynamics, and patchy dynamics (growth-decay-growth). Analysis of the data in China and Korea shows that the peak of infection (maximum of daily cases) is reached about 10 days after the restricting measures are introduced. During this period of time, the growth rate of the total number of infected was gradually decreasing. However, the growth rate remains exponential in Italy. Arguably, it suggests that the introduced quarantine is not sufficient and stricter measures are needed. [ABSTRACT FROM AUTHOR]

This paper reports the results of investigation on 0.1C-17Mn-5.5Ni-1.8Al-2.7W-4.6Mo-2.3Cu-0.002B steel designed to assume excellent combination of strength and toughness. The air induction melted steel was subjected to hot forging at 1200 °C followed by hot rolling in six passes from 1100 °C. The rolled samples were reheat-quenched from 1050 °C in iced water. The quenched samples were isochronally aged at temperatures within 500-650 °C at interval of 50 °C. The mechanical properties were determined by hardness measurement and tensile testing. Structural characterization was accomplished by x-ray diffraction, optical and electron microscopy. Differential scanning calorimetric study was conducted to understand the precipitation kinetics. A typical age-hardening behavior was noted in the aged samples due to the precipitation of M2C and Ni3Al. Strain hardening of martensite, precipitation hardening due to the presence of nanosized precipitates and Orowan hardening were found to be instrumental in attaining a maximum hardness of 723 HV. The microstructure of aged samples consists of retained austenite, ε-martensite, α′-martensite and uniformly distributed nanosized precipitates of Ni3Al and M2C, lying broadly within two different size regimes. The sample peak aged at 550 °C attained a strength of 1.4 GPa at a total elongation value of 25%. The combination of high strength and high ductility has resulted from precipitation strengthening, TRIP phenomenon and high degree of structural fineness. [ABSTRACT FROM AUTHOR]

ZnO nanomaterials are synthesized using one-pot synthesis method. Equimolar solution of Zinc Nitrate hexahydrate (Zn(NO3)2.6H2O) and Hexamethylenetetramine (C6H12N4) is used as a precursor for ZnO formation. Different nanostructures of ZnO are achieved by controlling the pH of the growth solution in the range 2–12 (acidic to alkali). ZnO nanostructures are evaluated for hydrophobic property using static contact angle measurement setup and UV photosensing activity. Surface morphology, structural properties and compositional analysis of ZnO nanostructures are examined by field emission scanning electron microscope (FE-SEM), energy dispersive X-ray analysis (EDX), high-resolution transmission electron microscope (FEG-TEM) and X-ray diffraction (XRD) measurements. Existence of ZnO wurtzite structure is confirmed from XRD study and is analyzed by Rietveld refinement method. Nanomaterials are characterized using Raman spectroscopy which confirms highest oxygen deficiency in ZnO nanorods. The material shows remarkable superhydrophobic and UV photosensing property and hence the name multifunctional. Among all morphologies grown at different pH values, ZnO nanorods show superhydrophobic nature with contact angle more than 170°. Total surface energy value of ZnO nanostructures is calculated using Wendt two-component theory. Different ZnO nanostructures (with variation of pH value) are used to study UV photosensing property. Responsivity and photocurrent show a strong dependence on the morphology of ZnO. [ABSTRACT FROM AUTHOR]

Purpose: There are two groups of undergraduate students involved in endoscopic surgery with different degrees of experience: average and more experience. This study proves whether the subjective impression of the laparoscopic trainer is verifiable and which factors influence extreme talent.Methods: 21 medical students of the eighth term of the University of Witten-Herdecke participated in the study. On their first course day, students got instructed in suturing and knot technique. They were then required to tie a maximum of five knots within 2 h. After a week, students repeated this procedure. Time used for tying knots was stopped.Results: Regarding the time students used for their first knots, great differences were provable (7-8 min, average 23 min). However, an adaption of the knotting time was noticed at the end of the first course day. This was confirmed during the second course day. Neither acquired factors (music, sport, etc.) nor individual factors (visual acuity, handedness, etc.) had any impact on the time used for knotting. Merely, one advantage was seen with the first knots with the factors of playing the guitar and having a more than 10-h surgical previous experience. Knotting times leveled off at 95% to less than 10 min, though.Discussion: Neither normally talented nor extremely talented junior surgeons could be noticed, and so could not the co-factors providing an advantage or disadvantage for surgery, respectively. All prospective surgeons can learn defined tasks (knots) by short interval training, and thus show similarly good results after a few repetitions. [ABSTRACT FROM AUTHOR]

The effect of multiwall carbon nanotube (MWCNT) content on the physical and mechanical properties of Fe-MWCNT composites has been studied. High-energy ball milling (HEBM) is employed to produce the composite powder; following this, spark plasma sintering (SPS) process has been adopted for powder consolidation. The composite powder and the sintered products were subjected to structural characterization by XRD. Microstructural studies were carried out by optical, field-emission scanning and high-resolution transmission electron microscopy. While Fourier transform infrared spectroscopic study of composites was done to understand the bonding characteristics, Raman spectroscopy was employed to assess the structural damage of MWCNT after HEBM. The effects of processing on the behavior of C-C, C-O and Fe-O bonds are studied by x-ray photoelectron spectroscopy. Microhardness and compressive strength of composites are also determined. Finally, magnetic and electrical properties of the composites were characterized. It was observed that optimized ball milling conditions help to preserve the structural identity of MWCNT. Consolidation by SPS insured good interfacial bonding. The microhardness and compression strength are significantly improved in MWCNT-reinforced iron matrix composite. MWCNT has appreciably improved the electrical conductivity of the composites. Tethering of MWCNT by iron oxide has led to appreciable improvement in saturation magnetization till 3 wt.% MWCNT. [ABSTRACT FROM AUTHOR]

Copper metal embedded fullerene C60 thin films are deposited on various substrates via resistive heating co evaporation technique. Rutherford back scattering simulated spectrum confirms the thickness and composition of thin film to be ~ 32 nm and ~ 18 at%, respectively. The deposited thin films are irradiated by 120 MeV Ag ion beam for different fluences within the range, from 1 × 1012 to 3 × 1013 ions/cm2. UV–vis absorption spectroscopy study reveals the appearance of surface plasmon resonance (SPR) band in pristine thin film at ~ 622 nm; this phenomenon is ascribed to the presence of copper nanoparticles in C60 matrix. The SPR band intensity increases with rising fluences, which is suggestive of the growth of Cu nanoparticles. Growth of Cu nanoparticles is further confirmed by transmission electron microscopic (TEM) and X-ray diffraction (XRD) study. Whereas the conversion of C60 into amorphous carbon (a-C) is confirmed by Raman spectroscopy, XRD results of pristine Cu–C60 thin film record the presence of Cu2O within the nanocomposite thin film. However, both X-ray photoelectron spectroscopy (XPS) and XRD studies on irradiated thin film samples authenticate the growth of Cu metal nanoparticles with concurrent removal of oxygen. [ABSTRACT FROM AUTHOR]

Films of pure polyvinyl alcohol (PVA) and its manganese chloride filled polymer composite film (MPVA) were prepared and their optical properties were evaluated. XRD, UV–vis, and FTIR analyses reveal that there is strong interaction between polyvinyl alcohol and manganese chloride. Interchain separation (R) for pristine PVA and MPVA composite films was found as 5.60 and 4.69 Ǻ, respectively, thus showing polymer chains are more compact in MPVA. Optical band gap of polyvinyl alcohol was reduced on incorporation of manganese chloride in polyvinyl alcohol to cause approximately 2.5‐fold increase in optical conductivity. Refractive index of MPVA was found to be higher than that of PVA in the visible range up to 710 nm but beyond that it became lower than that of PVA. Abbe Number was decreased on incorporation of manganese chloride to PVA with concomitant increase in dispersion energy. Urbach energy (Eu) for PVA and MPVA was found to be 0.70 and 0.82 eV, respectively. AFM study reveals formation of sunflower like assembled texture at nano‐scale level in MPVA film and it exhibits a higher root mean square (RMS) roughness and absorbance than those of pristine PVA film. Average oscillation wavelength (λ0) was found to be close to the respective absorption edge; and MPVA showed higher oscillation strength (S0) than that of PVA. POLYM. COMPOS., 40:E765–E775, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Kainic acid, an analogue of the excitatory neurotransmitter glutamate, can trigger seizures and neurotoxicity in the hippocampus and other limbic structures in a manner that mirrors the neuropathology of human temporal lobe epilepsy (TLE). However, the underlying mechanisms associated with the neurotoxicity remain unclear. Since amyloid‐β (Aβ) peptides, which are critical in the development of Alzheimer's disease, can mediate toxicity by activating glutamatergic NMDA receptors, it is likely that the enhanced glutamatergic transmission that renders hippocampal neurons vulnerable to kainic acid treatment may involve Aβ peptides. Thus, we seek to establish what role Aβ plays in kainic acid‐induced toxicity using in vivo and in vitro paradigms. Our results show that systemic injection of kainic acid to adult rats triggers seizures, gliosis and loss of hippocampal neurons, along with increased levels/processing of amyloid precursor protein (APP), resulting in the enhanced production of Aβ‐related peptides. The changes in APP levels/processing were evident primarily in activated astrocytes, implying a role for astrocytic Aβ in kainic acid‐induced toxicity. Accordingly, we showed that treating rat primary cultured astrocytes with kainic acid can lead to increased Aβ production/secretion without any compromise in cell viability. Additionally, we revealed that kainic acid reduces neuronal viability more in neuronal/astrocyte co‐cultures than in pure neuronal culture, and this is attenuated by precluding Aβ production. Collectively, these results indicate that increased production/secretion of Aβ‐related peptides from activated astrocytes can contribute to neurotoxicity in kainic acid‐treated rats. Since kainic acid administration can lead to neuropathological changes resembling TLE, it is likely that APP/Aβ peptides derived from astrocytes may have a role in TLE pathogenesis. [ABSTRACT FROM AUTHOR]

In the present work, a ternary Heusler alloy of composition Ni50Mn40Sn10 with a high martensitic transformation temperature has been prepared by arc-melting technique. The crystal structure of the obtained alloy is investigated by X-ray diffraction. The microstructure of the specimen sintered at 950°C for 72 h followed by ice-water quenching shows needle-like martensitic structure. Energy dispersive spectroscopy is utilized for compositional study. The differential scanning calorimetry result shows that the alloy undergoes a martensitic transformation at 190°C upon cooling. The M-H curve suggests paramagnetic nature of the martensite phase at room temperature. The present alloy system has a great potential to be used for high-temperature shape memory applications. Experimental data of this study may be useful for developing Ga-free high-temperature shape memory alloys. [ABSTRACT FROM AUTHOR]

High-energy ball milling (HEBM) of mixtures of iron powder and multi-walled carbon nanotube (MWCNT) has been performed in an attempt to synthesize nano-grained steel. Even after exposure to a harsh HEBM conditions, the MWCNTs are seen to have retained their structural identity, and therefore, an MWCNT-reinforced steel matrix composite could be finally produced. Moreover, the study has revealed that the minor addition of copper leads to a significant reduction in grain size of ferrite in the so-produced steel matrix-MWCNT composite. It is also noticed that the fine grain structure of ferrite remains intact even after consolidation of the powder composite by spark plasma sintering, followed by hot forging. The micro-hardness values obtained for the composites (with/without copper) are observed as comparable with the submicron-grained steels, so far reported in the literature. [ABSTRACT FROM AUTHOR]