Doping Effects In Off-stoichiometric Glow Discharge Amorphous Silicon Nitride

The effects of boron and phosphorus doping on the electrical properties of a-SiNx:H films are studied. The material is obtained by the glow discharge of SiH4 and N2 mixtures. It is found that for Si-rich materials boron doping produces large conductivity variations while phosphorus appears to be a much less efficient dopant. A phenomenological explanation is given assuming that phosphorus prefers to form bonds in accordance with its own valence configuration; i.e., it will go substitutionally to threefold coordinated N sites. Experimental evidence of such behavior obtained from published IR transmission measurements confirms this assumption.441116118IEEE Italy Sectio

Repositioning of the global epicentre of non-optimal cholesterol

High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol—which is a marker of cardiovascular risk—changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million–4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.</p

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. © 2019, The Author(s)

Repositioning of the global epicentre of non-optimal cholesterol

High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol�which is a marker of cardiovascular risk�changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95 credible interval 3.7 million�4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world. © 2020, The Author(s), under exclusive licence to Springer Nature Limited

Electrochromic Behaviour Of Sputtered Titanium Oxide Thin Films

The electrochromic reaction of titanium oxide films prepared by r.f. sputtering was studied. Chronoamperometric experiments associated with transmittance spectra in LiClO4-propylene carbonate solutions were carried out and compared with the optical properties of titanium oxide films with different stoichiometries. It was verified that the colour changes produced by stoichiometry deviation and by electro-intercalation are similar, because the maximum absorption bands in both cases are centred at the same wavelength and the molar absorption coefficients are similar; these observations can be explained by the mixed valence theory deduced for non-stoichiometric metallic oxides. The analysis of the j vs. E and [d(OD)/dt]vs. E potentiodynamic profiles is an interesting method for studying the kinetic mechanisms of electrochromic reactions without interference from parallel reactions. © 1995.25917074Lampert, (1984) Sol. Energy Mater., 11, p. 1Smith, (1982) Displays, 3, p. 3Smith, Transition metal oxide electrochromic materials and displays: a review (1982) Displays, 4, p. 67Ohzuku, Hirae, An electrochromic display based on titanium dioxide (1982) Electrochimica Acta, 27, p. 1263Ottaviani, Panero, Morzilli, Scrosatti, Lazzari, (1986) Solid State Ionics, 20, p. 197Morisaki, Yazawa, Electrochemical and electrochromic aspects of porous titania glass (1988) Applied Surface Science, 33-34, p. 818Doeuff, Sanchez, (1989) C.R. Acad. Sci. Paris, 309 (2), p. 531Seike, Nagai, (1991) Sol. Energy Mater., 22, p. 107Ozer, (1992) Thin Solid Films, 214, p. 17Canta˜o, Cisneros, Torresi, Kinetic Study of Lithium Electroinsertion in Titanium Oxide Thin Films (1994) The Journal of Physical Chemistry, 98, p. 4865Nassau, The Causes of Color (1980) Scientific American, 243, p. 36Deb, Optical and photoelectric properties and colour centres in thin films of tungsten oxide (1973) Philosophical Magazine, 27, p. 801Schirmer, Wittwer, Baur, Brant, (1977) J. Electrochem. Soc., 124, p. 749Hashimoto, Matsuoka, (1991) J. Appl. Phys., 69, p. 933Robin, Day, (1967) Advances in Inorganic Chemistry and Radiochemistry, 10, p. 247. , 4th edn., H.J. Emeléus, A.G. Sharpe, Academic Press, New YorkCotton, Wilkinson, (1972) Advanced Inorganic Chemistry, , Interscience, New YorkVogel, (1978) Quantitative Inorganic Analysis and Technical, , 4th edn., Longman Scientific, LondonCanta˜o, (1993) Ph.D. Thesis, , Instituto de Fisica “Gleb Wataghin”, Universidade Estadual de Campinas, Campinas, BrazilChapman, (1980) Glow Discharge Process, , Wiley, New YorkCisneros, Rego, Tomyiama, Bilac, Gonçalves, Rodriguez, Argüello, (1983) Thin Solid Films, 100, p. 155Swanepoel, (1983) J. Phys. E, 16, p. 1214Cronemeyer, Infrared Absorption of Reduced Rutile TiO2 Single Crystals (1958) Physical Review, 113, p. 1222Vratny, Micale, (1963) Trans. Faraday Soc., 59, p. 2739Stewart, (1970) Infrared Spectroscopy, , Marcel Dekker, New YorkMedvedeva, Zhukov, Khodos, Gubanov, The Electronic Structure and Cohesive Energy of HfO2, ZrO2, TiO2, and SnO2 Crystals (1990) physica status solidi (b), 160, p. 517Burstein, (1954) Phys. Rev., 93, p. 632Pleskov, Gurevich, (1986) Semiconductor Photoelectrochemistry, , Plenum, New Yor

Kinetic Study Of Lithium Electroinsertion In Titanium Oxide Thin Films

The electrochromic reaction of titanium oxide films prepared by RF sputtering was studied. Chronopotentiometric experiments associated with transmittance measurements in LiClO4/propylene carbonate solutions were carried out for several film thicknesses. The reaction kinetics is controlled by lithium ion diffusion into the titanium oxide matrix. The diffusion equations have been solved for the appropriate finite boundary conditions, and from these analyses l2/D values are obtained. Combining these data with coulometric titration data, one can conclude that the diffusion phenomenon is only produced in a part of the film. The l parameter was calculated and a value of 11 nm was obtained, coinciding with the thickness of the accumulation space charge layer for n-type TiO2. Consequently, Li+ diffusion process only occurs in this region. © 1994 American Chemical Society.98184865486

Bond Densities And Electronic Structure Of Amorphous Sinx:h

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)We present a study of amorphous hydrogenated silicon-nitrogen alloys (a-SiNx:H, 0 x1, Si-N bonds increase at the expense of both Si-Si and Si-H bonds; however, this is not enough to saturate the three N valencies with Si and some N-H and possibly N-N bonds begin to appear. The opening of the optical gap occurs at x 1.1 when the ratio of the densities of Si-Si bonds to Si-N bonds has fallen below 0.10. Near stoichiometry, substantial amounts of Si-Si and N-H bonds are observed. The possibility of segregation into pure silicon and stoichiometric silicon nitride is discussed by analyzing the Si 2p line shape. A linear relationship between the Si 2p chemical shift and the mean number of N-atom nearest neighbors of Si is observed; a charge transfer of 0.35e per Si-N bond is determined. © 1990 The American Physical Society.42956775684CAPES; Conselho Nacional de Desenvolvimento Científico e Tecnológico; CNPq; Conselho Nacional de Desenvolvimento Científico e Tecnológico; FAPESP; Conselho Nacional de Desenvolvimento Científico e TecnológicoFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP