Design and development of a compact thermal ionization mass spectrometer for isotope ratio measurement of uranium.

RATIONALE: A new compact thermal ionization (TI) mass spectrometer, for the isotope ratio analysis of the elements relevant to nuclear applications, has been designed and developed. The new development offers superior performance in terms of sensitivity, precision and a compact footprint in comparison with the conventional one. The main feature of the TI mass spectrometer is the magnetic sector analyser with a sector radius of 20 cm (instead of 30/27 cm in conventional/commercial geometry). An apparent reduction in dispersion has been adequately compensated by employing variable dispersion zoom optics (VDZO). METHODS: The theoretical calculations were validated by computer simulations using SIMION 7.0, leading to the finalization of the mechanical design. Experimental evaluation was carried out using standard TI mass spectrometric methodology to determine the parameters, namely peak flatness, mass range, sensitivity, abundance sensitivity, resolution and precision. RESULTS: The multi-collector resolution was 496, and the maximum mass was m/z 382. The sensitivity for uranium was found to be better than 1 ion for 500 atoms, and an abundance sensitivity of 50 ppm at m/z 237 was obtained. The peak flatness for the uranium peak was 3200 ppm of mass. The precision for the isotopic ratio 235 U/238 U was found to be 0.05% for the U200 standard. CONCLUSIONS: A new compact TI mass spectrometer with a 20 cm sector radius has been designed and developed. The advantage of larger dispersion produced by the VDZO (developed in-house) was exploited when deciding the 20 cm sector radius. The comparison study with the conventional TI mass spectrometer shows an enhanced (1.5×) sensitivity and an improved precision (0.05%) for the 235 U/238 U ratio of U200.

The Prevalence and Severity Comparison of COVID-19 Disease in SAARC Affiliated Countries: Pattern Analysis during the First Wave in 2020 / Prevalência e gravidade da COVID-19 em países afiliados à SAARC: análise de padrões durante a primeira onda em 2020

Objectives: This study aimed to explore the prevalence and severity of COVID-19 disease in SAARC affiliated countries and show the comparison by analyzing the patterns of infections, recoveries, and deaths among the countries. Methods: The data related to COVID-19 of SAARC affiliated countries were collected from Worldometer in which the dataset consists of daily confirmed, recovery, and death cases. To compare the prevalence and severity of COVID-19 among these countries, we consider three parameters such as case fatality rate (CFR), recovery-to-death ratio (RDR), and percent active case (PAC). Results: The highest daily CFR among the SAARC affiliated countries was in Bangladesh followed by Afghanistan, India, Sri Lanka, Pakistan, Nepal and the Maldives according to the maximum CFR of the countries until 24 October 2020. The highest RDR among the SAARC affiliated countries was in Nepal followed by the Maldives, Sri Lanka, India, Bangladesh, Pakistan, Afghanistan until 24 October. The most prevalent country according to infection per million people by COVID-19 among the SAARC affiliated countries is the Maldives followed by India, Nepal, Bangladesh, Pakistan, Afghanistan, Bhutan, and Sri Lanka as of October 24. The most death prevalent country per million people is India followed by the Maldives, Afghanistan, Bangladesh, Pakistan, Nepal, Sri Lanka, and no people died in Bhutan until October 24, 2020. Conclusion: This study shows that the severity of COVID-19 is high in the Maldives in terms of infections and India in terms of deaths per million in SAARC, so India is at high risk among the countries.

Objetivos: Este estudo teve como objetivo explorar a prevalência e gravidade da doença COVID-19 em países afiliados à SAARC e mostrar a comparação por meio da análise dos padrões de infecções, recuperações e mortes entre os países. Métodos: Os dados relacionados ao COVID-19 dos países afiliados à SAARC foram coletados do worldometer no qual o conjunto de dados consiste em casos diários confirmados, de recuperação e de óbito. Para comparar a prevalência e gravidade de COVID-19 entre esses países, consideramos três parâmetros, como taxa de letalidade (CFR), razão de recuperação para óbito (RDR) e porcentagem de casos ativos (PAC). Resultados: O CFR diário mais alto entre os países afiliados da SAARC foi em Bangladesh, seguido pelo Afeganistão, Índia, Sri Lanka, Paquistão, Nepal, Maldivas, de acordo com o CFR máximo dos países até 24 de outubro de 2020. O RDR mais alto entre os países afiliados da SAARC foi no Nepal, seguido por Maldivas, Sri Lanka, Índia, Bangladesh, Paquistão, Afeganistão até 24 de outubro. O país mais prevalente, de acordo com a infecção por milhão de pessoas por COVID-19 entre os países afiliados à SAARC, é as Maldivas, seguido pela Índia, Nepal, Bangladesh, Paquistão, Afeganistão, Butão e Sri Lanka em 24 de outubro. País com maior prevalência de morte em por milhão de pessoas é a Índia, seguida por Maldivas, Afeganistão, Bangladesh, Paquistão, Nepal, Sri Lanka, e nenhuma pessoa morreu no Butão até 24 de outubro de 2020. Conclusão: Este estudo mostra que a gravidade do COVID-19 é alta nas Maldivas em termos de infecções e na Índia, em termos de mortes por milhão na SAARC. Portanto, a Índia está em alto risco entre os países.

Infection and Death Patterns of COVID-19 Disease in Bangladesh / Padrões de infecção e morte da doença COVID-19 em Bangladesh

Objectives: This study aimed to reveal the prevalence of COVID-19 and investigate the patterns of deaths due to novel coronavirus in Bangladesh. Methods: The data about daily incidences, sex and deaths by the geography of COVID-19 for Bangladesh as of August 29, 2020 have been collected from the daily press releases of the Institute of Epidemiology, Disease Control and Research (IEDCR) and Directorate General of Health Services (DGHS). Case fatality rates (CFR), doubling time, correlation coefficient and graphical presentation were used to investigate the prevalence and patterns of infection and deaths. Results: Infection to tests, recovery to infections and death to infection rates due to novel coronavirus in Bangladesh until August 29, 2020 was 20.25%, 64.37% and 1.36% respectively. The correlation coefficient between daily tests and infections has found 0.978 with a 95% confidence interval 0.971 to 0.984. About 78.46% male and only 21.54% of females have died. Most deaths were found in the Dhaka division (48.26%) and the least deaths in the Mymensingh division (2.12%). The sex ratio of males to females in deaths was 364.23%. The age below 10 has found the least prevalent (0.45%) to deaths and above 60 has found most vulnerable (49.26%) to death. Conclusions: This study showed a strong positive relationship between daily tests and infections. The doubling time of infections and deaths in Bangladesh increased over time maintaining very low differences. Male people are more vulnerable to death compare to females. Aged people are extremely vulnerable to death. The most deaths geographical division is Dhaka and the least deaths in Mymensingh.

Objetivos: o objetivo deste estudo foi revelar a prevalência de COVID-19 e investigar os padrões de mortes por novos coronavírus em Bangladesh. Métodos: os dados sobre incidências diárias, sexo e mortes por geografia de COVID-19 para Bangladesh em 29 de agosto de 2020 foram coletados dos comunicados de imprensa diários do Instituto de Epidemiologia, Controle e Pesquisa de Doenças (IEDCR) e da Diretoria Geral de Serviços de Saúde (DGHS). As taxas de letalidade (CFR), o tempo de duplicação, o coeficiente de correlação e a apresentação gráfica foram usados para investigar a prevalência e os padrões de infecção e mortes. Resultados: as taxas de infecção para testes, recuperação de infecções e morte por infecção devido a novo coronavírus em Bangladesh até 29 de agosto de 2020 foram de 20,25%, 64,37% e 1,36%, respectivamente. O coeficiente de correlação entre os testes diários e infecções encontrou 0,978 com intervalo de confiança de 95% 0,971 a 0,984. Cerca de 78,46% homens e apenas 21,54% mulheres morreram. A maioria das mortes foi encontrada na divisão de Dhaka (48,26%) e menos mortes na divisão Mymensingh (2,12%). A proporção do sexo entre homens e mulheres nas mortes foi de 364,23%. A faixa etária abaixo de 10 apresentou menor prevalência (0,45%) aos óbitos e acima de 60 foi considerada mais vulnerável (49,26%) ao óbito. Conclusões: este estudo mostrou uma forte relação positiva entre testes diários e infecções. O tempo de duplicação de infecções e mortes em Bangladesh aumentou com o tempo, mantendo diferenças muito baixas. Os homens são mais vulneráveis à morte do que as mulheres. Pessoas idosas são extremamente vulneráveis à morte. A divisão geográfica com mais mortes é Dhaka e menos mortes é Mymensingh.

Simultaneous measurement of mass and rotation of trapped absorbing particles in air.

We trap absorbing micro-particles in air by photophoretic forces generated using a single loosely focused Gaussian trapping beam. We measure a component of the radial Brownian motion of a trapped particle cluster and determine the power spectral density, mean squared displacement, and normalized position and velocity autocorrelation functions to characterize the photophoretic body force in a quantitative fashion for the first time. The trapped particles also undergo spontaneous rotation due to the action of this force. This is evident from the spectral density that displays clear peaks at the rotation and the particles' inertial resonance frequencies. We fit the spectral density to the well-known analytical function derived from the Langevin equation, measure the resonance and rotation frequencies, and determine the values for particle mass that we verify at different trapping laser powers with reasonable accuracy.

Validation of a new serology-based dipstick test for rapid diagnosis of typhoid fever.

Currently, no reliable diagnostic test is available for typhoid fever. One serology-based dipstick test, developed indigenously, was validated in this study. Preserved sera from 336 fever patients with known culture results for Salmonella Typhi were blindly tested by the Widal test and the new assay. Analytical sensitivities, specificities, and efficiencies for the new assay versus the Widal test were 68.8% versus 62.5%, 71.1% versus 37.1%, and 70.5% versus 43.2%, respectively (p < 0.001), considering S. Typhi-positive samples as gold standards. Thereafter, fresh sera from 102 hospital-attending children with clinical typhoid fever (including 20 confirmed nontyphoidal cases as control) were tested by both methods and analyzed statistically. The diagnostic sensitivity, specificity, and efficiency were 51.2%, 85%, and 57.8% for the new assay, and 43.9%, 65%, and 48% for the Widal test, respectively. Overall performance ability of the new assay was not better than the Widal test (p > 0.5). Further improvement of the new point-of-care typhoid assay is recommended before implementation in the field setup.

Randomised controlled clinical trial of Lactobacillus sporogenes (Bacillus coagulans), used as probiotic in clinical practice, on acute watery diarrhoea in children.

OBJECTIVE: To assess the clinical efficacy of Lactobacillus sporogenes (Bacillus coagulans), as probiotic preparation, against dehydrating diarrhoea in children. METHODS: Double-blind, randomised, placebo-controlled, hospital-based clinical trial with children aged 6-24 months who had diarrhoea with some dehydration. Children received tablets of L. sporogenes (B. coagulans) or placebo (control group) and oral rehydration salt solution for correction of initial dehydration as well as maintenance therapy. Duration, frequency, volume of diarrhoea and intake of ORS of two groups were compared as outcome variables. RESULTS: One hundred and forty-eight children participated, of whom 78 (Study group) received L. sporogenes (B. coagulans) and 70 received placebo (Control group). Differences in recovery rate (P=0.2), duration (P=0.5), frequency (P=0.05), volume (P=0.1) of diarrhoea, intake of ORS (P=0.2) and other fluids (P=0.1) were not significant between both groups. Neither did a subgroup analysis of children who had rotavirus as sole enteropathogens show any significant differences in duration (P=0.5), frequency (P=0.6), volume (P=0.8) of diarrhoea, intake of ORS (P=0.8) and other fluids (P=0.8) among both groups. CONCLUSION: L. sporogenes (B. coagulans), as an adjunct to ORS, had no therapeutic impact on management of acute dehydrating diarrhoea of diverse etiology including rotavirus associated diarrhoea in children.

Assessment of Malnutrition Among Adolescents:Can BMI be Replaced by MUAC.

OBJECTIVES: To find out the magnitude of malnutrition among the adolescents of an urban slum of Kolkata study population. To compare the middle upper arm circumference (MUAC) with that of body mass index (BMI) for determination of nutritional status of the study population. MATERIALS AND METHODS: This was a school-based descriptive epidemiological study done among adolescent male students aged 10-19 years in the service area of Urban Health Centre, Chetla. The school is an all boy's government aided school and all the students reside in the Chetla slum, the largest slum of Kolkata. Anthropometric measurements of the students of one section selected from each class i.e. class V to XII were recorded. RESULTS: Results showed 47.93% of study population as per BMI and 60.30% as per MUAC were malnourished. Evaluation of screening test showed MUAC as a marker was 94.6% sensitive and 71.2% specific. A correlation between measurements of MUAC and BMI was demonstrated (r=0.822; SE=0.035; 95% CI; P=0.000000; r(2)=0.74).