Determination of the fracture toughness of polycarbonate using an energy approach

A number of polycarbonate (PC) specimens, having the same compact tension type configuration but with different initial crack lengths, was tested at -12[deg]C under Mode I type loading. The pop-in loads and corresponding displacements at the loading pins were plotted and connected by a common curve. The value of KIC was determined using the method first proposed by Gurney and Hunt and was in close agreement with values reported by others. It is concluded that the pop-in load versus displacement curve is equivalent to a locus describing crack propagation under plane-strain conditions and suggests a new approach for determining KIC for ductile solids.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25364/1/0000812.pd

Aldosterone receptor assay in rat kidney cytosol

A method has been developed to measure aldosterone receptors using rat kidney cytosol preparations. Addition of 0.1 M Na molybdate to homogenization buffer markedly diminished receptor inactivation, allowing for more accurate assessment of affinity and total number of receptors. Statistical analysis of Scatchard plots was used to resolve curvilinear plots into high affinity (type I) and a low affinity (type II) components. Aldosterone and deoxycorticosterone compete most effectively for binding to type I sites, whereas dexamethasone competes most effectively for binding to type II sites. Molybdate does not alter the location of the 8.0S peak on density gradient analysis. Assay of type I sites revealed 47.7 +/- 1.7fmol/ml cytosol protein in male adrenalectomized rats. Constant of dissociation (KD) was measured at 5.08 x 10-10 M. Non-adrenalectomized male rats had 24.4 +/- 3.0 fmol/mg protein type I sites. Addition of molybdate to homogenization buffer combined with statistical analysis of curvilinear Scatchard plots allows for accurate and reproducible measurement of high affinity aldosterone receptors in rat kidney cytosol.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23214/1/0000143.pd

Ductile Fracture Toughness Determined on an Energy Basis Using Polycarbonate.

The quasi-static crack propagation method to measure fracture toughness has been investigated. This method has long been known to be valid when measuring the toughness of brittle materials. It is recognized as being basically different from other methods, e.g., K(,Ic), G(,Ic), J Integral, etc., because these methods apply to the onset of crack propagation whereas the investigated method applies to both initiation and propagation of a crack running under quasi-static conditions. This thesis reports the extension of the applicability of the quasi-static propagation method to a ductile fracture where displacement is not fully recoverable. It was found that by connecting the "pop-in" points of several specimens on a load-displacement diagram, each specimen having a different initial crack length, plane-strain fracture toughness can be found with specimens whose thicknesses are smaller than 2.5 (K(,Ic)/(sigma)(,y))('2), as recommended by ASTM Designation #E399-74. An important finding was in separating the energy expended between the plane-strain and plane-stress portions of the fractured surface, and the contributions of those two toughnesses to the total toughness was found.Ph.D.Mechanical engineeringUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/158361/1/8116350.pd

The effect of adrenal steroids on electrolyte excretion.

The regulation of water and electrolyte metabolism has been the subject of much investigation. Many factors have been implicated, one being that volume plays a role in the regulation of sodium in the body. It has been suggested that there may be receptors somewhere in the body, which are sensitive to changes in the volume of fluid or in the concentration of electrolytes. It has not been clearly established yet whether they are sensitive to blood volume, plasma colloid osmotic pressure, interstitial fluid volume, or some other factor. The importance of the adrenal cortex in influencing sodium metabolism is well established

Japan's Dual Broadcasting System

Master of ArtsCenter for Japanese StudiesUniversity of Michiganhttps://deepblue.lib.umich.edu/bitstream/2027.42/144918/1/cjsmat_227.pdf45

The effect of adrenal cortical hormones on electrolyte excretion.

The importance of tile adrenal cortex in influencing sodium and potassium metabolism is well established. The adrenal cortex secretes a number of steroid hormones which affect sodium and potassium excretion to varying degrees. The hormone which is the most potent in its sodium retaining effect is aldosterone. It promotes the sodium reabsorption for the exchange of potassium or hydrogen ion in the distal tubules of the kidney. There are several problems which are not well understood, e.g. the physiological importance of the rate of secretion of various steroids, the synergistic or antagonistic action of various adrenal cortical hormones on the absorption, distribution and excretion of electrolyte and their interplay with each other

Práticas e comportamentos sexuais de imigrantes que vivem em Portugal

As infeções sexualmente transmissíveis (ISTs) possuem distribuição mundial, constituindo grave problema de saúde pública a nível mundial, de difícil controlo. Estas infeções apresentam-se como uma das principais causas de mortalidade e morbilidade significativas e propiciam a transmissão da HIV/SIDA. Verifica-se que os migrantes representam uma larga percentagem dos novos casos de ISTs, particularmente VIH, a nível global. Sendo Portugal um país tipicamente recetor de imigrantes sobretudo originários da comunidade de países da língua portuguesa, e perante o aumento de globalização, surgiu a necessidade de caracterizar o padrão de prática e comportamento sexual de imigrantes portadores de VIH+ que vivem em Portugal, objetivo geral do presente trabalho. Através do método não probabilístico, selecionaram-se, 265 imigrantes portadores de VIH+ residentes em Portugal, com vida sexual iniciada e idade igual ou superior a 18 anos. Tendo em conta aos objetivos delineados, seguiu-se um desenho de estudo observacional, analítico e transversal. Para a recolha de dados recorreu-se a um questionário de perguntas de resposta fechada. Verificou-se que os participantes no presente estudo são maioritariamente jovens, do género masculino e heterossexuais, detentores do ensino secundário ou superior, e naturais de países da língua portuguesa. Outro dado importante encontrado no nosso estudo, refere-se à maior prevalência e associação das ISTs entre os homens que fazem sexo com homens (HSH). No presente estudo verificou-se que maior parte de imigrantes que contraíram ISTs foram das comunidades de países da língua portuguesa. Feita a reflexão sobre os dados obtidos no presente estudo, e numa tentativa de continuar a diminuir a transmissão de ISTs, particularmente vírus de HIV na era de globalização que vivemos, lembramos que devem ser promovidas medidas direcionados para os imigrantes. Dados encontrados apontam a necessidade de continuar a aposta e investimento em cuidados preventivos que envolvam essencialmente populações vulneráveis, particularmente os migrantes, abordar o tema de promoção e da prevenção da transmissão de ISTs em espaços frequentados por estas comunidades, e continuar a priorizar formação de profissionais de saúde quanto a cuidados de saúde na população imigrantes.Sexually transmitted infections (STIs) have a worldwide distribution, constituting a serious public health problem worldwide, which is difficult to control. These infections are one of the main causes of significant mortality and morbidity and favor the transmission of HIV/AIDS. It appears that immigrants represent a large percentage of new cases of STIs, particularly HIV, globally. As Portugal is a typically receiving country for immigrants, mainly from the community of portuguese-speaking countries, and given the increase in globalization, the need arose to characterize the pattern of sexual practice and behavior of HIV+ immigrants living in Portugal, the general objective of the present work. Through the non-probabilistic method, 265 immigrants with HIV+ residing in Portugal, with initiated sexual life and aged 18 years or older, were selected. Taking into account the objectives outlined, an observational, analytical and cross-sectional study design was followed. For data collection, a questionnaire with closed-ended questions was used. It was found that the participants in the present study are mostly young, male and heterosexual, with secondary or higher education, and natives of Portuguese-speaking countries. Another important finding in our study refers to the higher prevalence and association of STIs among men who have sex with men (MSM). In the present study, it was found that most immigrants who contracted STIs were from communities in Portuguese-speaking countries. After reflecting on the data obtained in the present study, and in an attempt to continue to reduce the transmission of STIs, particularly the HIV virus in the era of globalization we live in, we recall that measures aimed at immigrants must be promoted. The Data indicated the need to continue investing and investing in preventive care that essentially involve vulnerable populations, particularly migrants, addressing the issue of promoting and preventing the transmission of STIs in spaces frequented by these communities, and continuing to prioritize training of professionals and health care in the immigrant population