Statistical proportion

Abstract: The process of freeze-thaw not only subjects bioproducts to potentially destabilizing stress, but also imposes challenges to retain container integrity. Shipment and storage of frozen products in glass vials and thawing of the vials prior to use at clinics is a common situation. Vial integrity failure during freeze-thaw results in product loss and safety issues. Formulations of biomolecules often include crystallizable excipients, which can cause glass vial breakage during freeze-thaw operations. In this study, mannitol formulations served as models for mechanistic investigation of root causes for vial breakage. Several parameters and their impacts on vial breakage were investigated, including mannitol concentration (5% and 15%), different freeze-thaw conditions (fast, slow, and staging), fill configurations (varying fill volume/vial size ratio), and vial tray materials (plastic, stainless steel, corrugated cardboard, aluminum, and polyurethane foam). The results in this study were subjected to a statistical proportion test. The data showed that large fill volumes strongly correlated with higher percentage of vial cracks. Furthermore, the 15% mannitol was found to cause more breakage than 5% mannitol, especially with fast temperature gradient. Significantly more thawing vial breakage occurred in the fast compared to slow freeze-thaw with all types of vial trays. The freezing breakage was substantially lower than the thawing breakage using the fast temperature gradient, and the trend was reversed with the slow temperature gradient. An intermediate hold at -30 degrees C prior to further decrease in temperature proved to be a practical approach to minimize mannitol-induced vial breakage. Thermal mechanical analysis (TMA) and strain gage techniques were employed to gain mechanistic insights, and it was found that the primary causes for mannitol-induced vial breakage were partial crystallization during freezing and "secondary" crystallization of non-crystallized fraction during thawing. The strain on the vial's axial direction was significantly higher than the hoop direction, typically resulting in bottom lens of the vial coming off. Without a -30 degrees C hold, rapid volume expansions due to initial crystallization and secondary crystallization of mannitol were observed in TMA profiles, and these expansions were more apparent in 15% mannitol compared to 5% mannitol. With the introduction of a -30 degrees C hold step, abrupt expansions diminished in TMA profiles, suggesting that most of the mannitol crystallization occurred concurrently with ice solidification during the -30 degrees C holding step and, thus, secondary crystallization during thawing was minimal and the sudden expansion event was eliminated. Therefore, vial breakage during both freezing and thawing was reduced.

Abstract: Although guardrail systems are designed to reduce crash impacts for errant vehicles, the actual effects of in-service guardrail on reducing crash severity have been rarely validated and quantified. This article uses real-world guardrail and crash data to assess the effectiveness of guardrail systems in reducing fatal and severe injury crashes. A roadway departure crash severity model is developed using binary logit model, and statistical proportion tests are conducted to compare roadway departure crash severity with and without guardrail hits. Both methods suggest that hitting guardrail could reduce the probability of fatal and severe injury by about 45% to 50% and that the reduction is statistically significant. A unique approach of this article is to pair each roadway departure crash hitting a guardrail with the corresponding guardrail inventory using advanced spatial analysis technique so that the effects of different guardrail types on crash severity can be explored. The results indicate that ...

Abstract: INTRODUCTION Social factors play vital role in unfolding of alcohol use disorders in any given population. Several factors beyond the confines of treatment settings influence treatment outcome in alcohol dependence syndrome. Social support has positive effect in treatment outcome of alcohol dependence syndrome. This has not been much studied in India in past. Therefore we decided to study the perception of social support in cases of alcohol dependence syndrome admitted in a busy hospital in armed forces. AIM The aim was to study the perception of social support across relapsed and abstinent group and see if it reached any statistical proportion and also to see if any socio-demographic variables also affected perception of social support. MATERIALS AND METHODS Fifty five consecutive male patients of alcohol dependent syndrome without a co-morbid neurological/psychiatric diagnosis were assessed for their perception of social support after taking informed consent. They were explained the procedure and their alcoholic milestones were recorded in specially designed pro-forma. Subjects were then divided in abstinent and relapsed group. Subsequently they were assessed for their perception of social support by administering Social provision scale and Social support questionnaire. STATISTICAL ANALYSIS Data were tabulated and statistically analysed by using chi square test, Mann Whitney U-Test and Rank ANOVA test where applicable p-value <.05 was taken as significant. RESULTS Results indicated that perception of social support across abstinent (n=18) and relapsed (n= 37) group reached significant statistical proportion as measured by social provision scale and social support questionnaire. Duration of use, dependence and family history of alcoholism did not influence perception of social support across patient population. There was inverse relationship between patients with alcohol related problem and their perception of social support. Professional and qualified soldiers perceived higher social support than soldiers and lesser qualified individuals. CONCLUSION Abstinent group perceived better social support than relapsed group and soldiers in upper socio-occupational status and less alcohol related problems perceived more social support than soldiers with lower socioeconomic status and more alcohol related problems. Psychosocial therapy must be incorporated in management of Alcohol dependence syndrome.

Abstract: The internal energies of [C3H7]+ ions contributing to the metastable peak [C3H7]+ [C3H5]+ + H2 are higher (by perhaps > 100 kJ mol−1) than those of the ion contributing to the threshold current in appearance energy measurements on [C3H5]+. The measured appearance energy may lead to an underestimation of the activation energy, i.e. negative ‘kinetic shift’, due to quantum, mechanical tunnelling. The distribution of energy released in the decomposition can be explained on the basis that much of the reverse activation energy and a statistical proportion of the excess energy is released as translation.