Soil properties and constituents in relation to mechanisms of sulphate adsorption

Published March 1962. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Evaluation of Plasma Charging Damage in Ultrathin Gate Oxides

Abstract-Monitoring of plasma charging damage in ultrathin oxides (e.g., <4 nm) is essential to understand its impact on device reliability. However, it is observed that the shift of several device parameters, including threshold voltage, transconductance, and subthreshold swing, are not sensitive to plasma charging and thus not suitable for this purpose. Consequently, some destructive methods, such as the charge-to-breakdown measurement, are necessary to evaluate plasma damage in the ultrathin oxides. Index Terms-Dielectric breakdown, plasma materialsprocessing applications, semiconductor device reliability

A molten globule-to-ordered structure transition of Drosophila melanogaster crammer is required for its ability to inhibit cathepsin

Drosophila melanogaster crammer is a novel cathepsin inhibitor that is involved in LTM (long-term memory) formation. The mechanism by which the inhibitory activity is regulated remains unclear. In the present paper we have shown that the oligomeric state of crammer is pH dependent. At neutral pH, crammer is predominantly dimeric in vitro as a result of disulfide bond formation, and is monomeric at acidic pH. Our inhibition assay shows that monomeric crammer, not disulfide-bonded dimer, is a strong competitive inhibitor of cathepsin L. Crammer is a monomeric molten globule in acidic solution, a condition that is similar to the environment in the lysosome where crammer is probably located. Upon binding to cathepsin L, however, crammer undergoes a molten globule-to-ordered structural transition. Using high-resolution NMR spectroscopy, we have shown that a cysteine-to-serine point mutation at position 72 (C72S) renders crammer monomeric at pH 6.0 and that the structure of the C72S variant highly resembles that of wild-type crammer in complex with cathepsin L at pH 4.0. We have determined the first solution structure of propeptide-like protease inhibitor in its active form and examined in detail using a variety of spectroscopic methods the folding properties of crammer in order to delineate its biomolecular recognition of cathepsin

Women with endometriosis have higher comorbidities: Analysis of domestic data in Taiwan

AbstractEndometriosis, defined by the presence of viable extrauterine endometrial glands and stroma, can grow or bleed cyclically, and possesses characteristics including a destructive, invasive, and metastatic nature. Since endometriosis may result in pelvic inflammation, adhesion, chronic pain, and infertility, and can progress to biologically malignant tumors, it is a long-term major health issue in women of reproductive age. In this review, we analyze the Taiwan domestic research addressing associations between endometriosis and other diseases. Concerning malignant tumors, we identified four studies on the links between endometriosis and ovarian cancer, one on breast cancer, two on endometrial cancer, one on colorectal cancer, and one on other malignancies, as well as one on associations between endometriosis and irritable bowel syndrome, one on links with migraine headache, three on links with pelvic inflammatory diseases, four on links with infertility, four on links with obesity, four on links with chronic liver disease, four on links with rheumatoid arthritis, four on links with chronic renal disease, five on links with diabetes mellitus, and five on links with cardiovascular diseases (hypertension, hyperlipidemia, etc.). The data available to date support that women with endometriosis might be at risk of some chronic illnesses and certain malignancies, although we consider the evidence for some comorbidities to be of low quality, for example, the association between colon cancer and adenomyosis/endometriosis. We still believe that the risk of comorbidity might be higher in women with endometriosis than that we supposed before. More research is needed to determine whether women with endometriosis are really at risk of these comorbidities

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

Rising rural body-mass index is the main driver of the global obesity epidemic in adults

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.Peer reviewe

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions

Measurement of Ultrathin (<100 Oxide Films by Multiple-Angle Incident Ellipsometry

ABSTRACT The application of the multiple-angle incident ellipsometry to measure the ultrathin (< 100 A) oxide has been studied in this paper. First, four interfacial models are investigated by using a fitting scheme to fit ellipsometric data (h, ~) at various incident angles, and the abrupt model is found to be the most appropriate model to model the transition region of the SiO2-Si interface. The sensitivities on the incident angle and the errors induced by the ellipsometric parameter variations are also analyzed. Ellipsometry is applied to measure the native oxides of Si wafers after they are treated with different cleaning processes, and it is also applied to measure refractive indexes and thicknesses of ultrathin thermally grown SiO2. It is believed that these are the most accurately measured results on the refractive indexes of ultrathin oxides. Also, an empirical formula for thermal oxide growth in dry 02 is obtained. Thin dielectrics find many applications in metal oxide semiconductor (MOSFET) devices, especially as the gate insulators of MOSFET. As very large scale integrated (VLSI) technology continues to advance, the gate insulators, usually oxides, are getting thinner and thinner. It is predicted that, at the year of 2000, the thickness of the gate oxide will be 40 A (1). Much research work has been devoted to studying the preparation, physics, and device applications of thin dielectrics (2, 3). In these studies, it is important to measure precisely the thickness of thin dielectric. For example, one of the needs is to measure accurately the thickness of thin oxides in studying their oxidation kinetics, especially at the initial oxidation stage (4-6), in order to accurately model the growth process. Another example is that, in studying the carrier conduction mechanism in tunneling oxides for their applications in the electrically erasable programmable read-only memory (EEPROM), it is required to obtain the exact thickness of oxides in order to properly model the carrier conduction process, since several angstroms of error in the oxide thickness could lead to one order of magnitude deviation in calculating the I-V characteristics (7, 8). To measure the oxide thickness, ellipsometry is usually employed because of its simplicity, nondestructiveness, and easy sample preparation (9). As early as 1957, this method had been used to study the oxide growth kinetics of silicon and germanium when they were exposed to the room air (10). Besides measuring thickness, it can also measure the refractive index of the film. Today, ellipsometers, either the nulling type or the rotary type, have been manufactured as automatic instruments to characterize thin films and the measurement results can be obtained within 30 s for one measurement (9). However, when it is applied to measure ultrathin dielectric films, serious errors could occur due to measurement random errors and the instrumental systematic errors To measure the precise thickness of the ultrathin oxide with ellipsometry, a common practice is that the measured ellipsometric data (h, ~) are substituted into ellipsometric equations (11) to solve for the thickness T by assuming a known value for the refractive index N for the oxide. The obtained oxide thickness is then doubly checked with the data obtained with the C-V measurement on the metal oxide capacitor (MOS) capacitor made with the oxide of the same thickness (14). With this practice, if the N value is assumed rightly, errors can be significantly reduced, as indicated by the analyzed results of Ref. The interfacial property of the Si-SiO2 system affects the measurement data significantly, especially for the ultrathin (<50 A) region. Much work has done on this topic based on the use of Auger spectroscopy, electron spectroscopy for chemical analysis (ESCA), Rutherford He backscattering spectroscopy, transmission electron microscopy (TEM), x-ray photoelectron spectroscopy, low-energy ion scattering spectroscopy, infrared spectroscopy and the ellipsometery (17-22). Reference (23) summarizes the results of the above studies on the interfacial transition layer of the Si-SiO2 system. Although the results are controversial, it is fairly safe to say that different oxidation conditions result in a transition layer of different thickness and optical property, and either an abrupt transition layer of two to three atomic layers or a graded transition layer of smaller than 20 A can be used to model the interfacial transition layer of the Si-SiO2 system. For the ellipsometry measurement on ultrathin oxides, the conventional ellipsometry of single wavelength and single incident angle suffers the drawback of inaccuracy mentioned above. Multiple wavelength ellipsometry had been used, and it offered more than two sets of (h, ~) data which could be used to improve the accuracy for the derived values for N and T (24, 25). However, multiple wavelength ellipsometry suffers the problem of dispersiveness of the measured film. Also, it needs the information of the refractive index at various wavelengths for the silicon substrate. Single wavelength multiple incident angle ellipsometry, which does not have the above problem, offers multiple sets of (A, ~) data which can be used to fit the values for the refractive index and the thickness of the measured film. As early as 1964, Crackin and Colson (26) had used it to measure properties of thin films. In multiple angle incident (MAI) ellipsometry, a fitting procedure is usually employed. Ibrahim and Bashara (27) have studied the parameter correlation for the numerical fitting process and found that the initial guesses on parameters were important on the final computed solutions. It was suggested that the refractive index and the thickness of the measured films should be independently estimated. In this paper, a null-type MAI elIipsometry with a 6328 A He-Ne laser source is studied for its application to measure the ultrathin (<100 A) oxide. Four transition layer models 175