Combined Effect of Temperature and Relative Humidity on the Survival of Salmonella Isolates on Stainless Steel Coupons

The survival on stainless steel of ten Salmonella isolates from food factory, clinical and veterinary sources was investigated. Stainless steel coupons inoculated with Salmonella were dried and stored at a range of temperatures and relative humidity (RH) levels representing factory conditions. Viability was determined from 1 to 22 days. Survival curves obtained for most isolates and storage conditions displayed exponential inactivation described by a log-linear model. Survival was affected by environmental temperatures and RH with decimal reduction times (DRTs) ranging from <1 day to 18 days. At 25 °C/15% RH, all isolates survived at levels of 103 to 105 cfu for >22 days. Furthermore, temperatures and RH independently influenced survival on stainless steel; increasing temperatures between 10 °C and 37 °C and increasing RH levels from 30–70% both decreased the DRT values. Survival curves displaying a shoulder followed by exponential death were obtained for three isolates at 10 °C/70% RH. Inactivation kinetics for these were described by modified Weibull models, suggesting that cumulative injury occurs before cellular inactivation. This study highlights the need to control temperature and RH to limit microbial persistence in the food manufacturing environment, particularly during the factory shut-down period for cleaning when higher temperature/humidity levels could be introduced.

Специфика статистики упругих и деформационно-прочностных свойств высокопрочных волокон полипропилена

Regularities of statistical distributions of a complex of mechanical properties, including the module of elasticity (E), strength () and strain at break (b), high-strength industrial oriented polypropylene (PP) fibers have been analyzed using the Weibull and Gauss models based on large a wide array of measurements (50 identical samples in each series). The values of the statistical Weibull modulus (m) - a parameter characterizing the scatter of the measured values of the data arrays of E,  and b – have been estimated for the PP samples of two types: single fibers (monofilaments) and multifilament fibers consisting from several hundred single fibers. For the PP multifilament fibers, a more correct description of the distributions of E,  and b has been received both in the framework of the normal distribution (Gaussian distribution) and in the framework of the Weibull distribution in comparison with the description of such distributions for the PP monofilaments. The influence of the polymer chain conformation on the regularities of the statistical distributions of E,  and b for the high-strength oriented polymeric materials with different chemical chain structures and the correctness of their descriptions in the framework of the Gauss and Weibull models have been analyzed. For this purpose, the values of m calculated in this work for PP with a helical chain conformation have been compared with the values of m determined by us earlier for ultra-high molecular weight polyethylene and polyamide-6 with the chain conformations in the form of an in-plane trans-zigzag.

Role of Nativity in End of Life Care Planning

Given the rapidly aging population, optimal end-of-life (EOL) consistent with individual wishes is a public health priority. Advanced Care Planning (ACP) involves Advanced Directives (AD) and establishing a Power of Attorney (POA). AD describe EOL Care preferences including options to limit treatment, withhold treatment, provide comfort care, and prolong treatments. Nativity can provide meaningful guidance in decision-making at the end of life. Data from this study came from the Health and Retirement Study, nationally representative longitudinal study of U.S. residents. The sample included 4,015 older adults, 65 and above years of age who died during study follow-up. Nativity was categorized as U.S born and Foreign born. ACP variables included presence of AD and POA, and EOLC preferences included provide comfort care, limit, withhold, or prolong treatment. Covariates included age, gender, race, marital status, education, and subjective health at baseline. Cox Proportional Hazards (Cox PH) and Weibull Models were used to identify associations between nativity and end of life care. Results: Compared to U.S born, Foreign born participants were less likely to have POA (HR: 0.75; 95% CI:0.64-0.89) in Cox PH and POA (HR: 0.63; 95 % CI:0.53-0.75) Weibull models in unadjusted models, limited treatment (HR: 1.58; 95 % CI: 1.2, 2.1), and prolong treatment (HR: 0.23; 95 % CI:0.06-0.99) and Cox PH and (HR: 0.20; 95 % CI: 0.05-0.83) in Weibull modes. Conclusion: There are differences in Advanced Care Planning by nativity. Country of origin should be considered when helping individuals plan for end-of-life care.

Learning Interpretable Mixture of Weibull Distributions—Exploratory Analysis of How Economic Development Influences the Incidence of COVID-19 Deaths

This paper presents an algorithm for learning local Weibull models, whose operating regions are represented by fuzzy rules. The applicability of the proposed method is demonstrated in estimating the mortality rate of the COVID-19 pandemic. The reproducible results show that there is a significant difference between mortality rates of countries due to their economic situation, urbanization, and the state of the health sector. The proposed method is compared with the semi-parametric Cox proportional hazard regression method. The distribution functions of these two methods are close to each other, so the proposed method can estimate efficiently.

Statistical analysis of measured wind speed data’s appealing spreadsheet applications

Once the wind data is measured, the values are processed, based on statistic approach, as accurately as possible, to provide a clear over-view of the locations wind potential, being the basis of any wind farm project, representing the go or no-go in further subsequent design steps. The probability density distributions are derived from time-series data, identifying the associated distributional parameters. The wind energy potential of the locations is studied based on the Rayleigh and Weibull models, implemented with the help of Excel computations, and representing tools, to understand the wind characteristics. Based on the statistical analysis of wind conditions presented here, the results of current study can be used to make a sustainable energy yield for any location.

PHARMACEUTICAL QUALITY ASSESSMENT OF GLIMEPIRIDE TABLETS – COMPARISON OF BRANDS AND NEWLY FORMULATED TABLETS WITH INNOVATOR

Objective: The main objective of the study was to assess the quality attribute of generic brands and newly formulated tablet of glimepiride and compare their drug release profile with innovator brand. Methods: Different brands were purchased from different markets of UAE. The validated high-performance liquid chromatography method was used to assess the quantitative analysis of glimepiride. The linearity of curve (r² = 0.9999) indicated the accuracy and precision of the analytical method. Comparative dissolution of newly formulated and generic tablets was carried out using USP dissolution apparatus II. Study was accomplished in phosphate buffer (pH = 7.8), the paddle speed was adjusted at 75 rpm. F1 and F2 factor among the brands and kinetic assessment were done to obtain the order of release. Results: Dissolution profiles of formulated tablets were almost same as that of innovator, 91.53 and 94.9, respectively, in 15 min. The statistical value between the different brands (F = 3.698) indicated that there were some differences among the few groups of tablets and p-value (0.002154) indicated that it supported H1 hypothesis. First-order and Weibull models described the drug release with r2 value of 0.9981–0.927210 and 0.9992– 0.9835, respectively. Stability of optimized formulated batch was also examined. Conclusion: It was concluded that the formulated tablets are stable and pharmaceutically as good as the innovators; however, all the selected brands could not be used interchangeably in the clinical practice. It was also concluded that the scrutiny and screening of the drug products, available in the markets, can help to build a better health-care setup.

Graduation of term assurance data using frailty approach

Frailty models have been used in literature to account for heterogeneity among insureds in-terms of mortality. In this article, we compare the gamma and the non-central gamma as frailty distributions with the exponentiated exponential and exponentiated Weibull as baseline hazards. We adopt a fully Bayesian approach to calibrate the baselines based on crude mortality rates from a major Kenyan insurer. Comparing the gamma-exponentiated Weibull with the non-central gamma-exponentiated Weibull models shows that the non-central gamma provides a good fit to the real life data-set and is therefore recommended for valuation.

A Survival Analysis of Invasive Fungal Diseases in Children with Cancer

Objective The study aimed to determine the survival in a retrospective cohort of 152 patients treated for invasive fungal diseases (IFD) (133 proven and 19 probable) in 9 years. Methods The study included patients aged 0 to 18 years diagnosed with cancer at our institution and with proven or probable IFD, treated from 2011 to 2019. Weibull distribution was used for hazard ratios and accelerated failure time models for the outcome “death attributed to IFD.” Results The median age was 97 months. The most frequent diagnosis was leukemia (39, 25.7%). A total of 37 patients received prophylaxis with fluconazole (24.3%). Among 133 fungal isolates, the most frequent were Candida species in blood 81 (53.2%). Moreover, 43 deaths were attributed to IFD (28.3%). Survival probabilities were lower for pulmonary IFD (46.9%, p = 0.0017), leukemia (62.5%, p = 0.004), and neutropenia <500 cells/mm3 (55.4%, p < 0.0001). For Candida fungemia, survival probabilities were 76.6% (p = 0.043). In Weibull models, the diagnosis of leukemia shortened survival times by a factor of 0.006, relapse of disease by 0.05, lymphoma by 0.04, pulmonary IFD by 0.04, and neutropenia by 0.015. Hematopoietic stem cell transplantation did not affect the survival times as well as prophylaxis with fluconazole. Conclusion Host factors, such as neutropenia, relapse of disease, and hematologic malignancies, are determinants in the survival times of children with IFD as well as pulmonary involvement.

A Study on Various Transformation Method of Weibull Distribution: A Review

In this article a brief summary of some recent developments of Weibull lifetime models has been presented for a quick overview. Various extensions of the Weibull models and the properties of the extended Weibull distribution have been discussed. A brief discussion about the characteristics and shape behaviour has been presented in the tabular form. Finally, some future research topics have been given.