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Abstract Hydrogen bond symmetrisation is the phenomenon where a hydrogen atom is located at the centre of a hydrogen bond. Theoretical studies predict that hydrogen bonds in ice VII eventually undergo symmetrisation upon increasing pressure, involving nuclear quantum effect with significant isotope effect and drastic changes in the elastic properties through several intermediate states with varying hydrogen distribution. Despite numerous experimental studies conducted, the location of hydrogen and hence the transition pressures reported up to date remain inconsistent. Here we report the atomic distribution of deuterium in D2O ice using neutron diffraction above 100 GPa and observe the transition from a bimodal to a unimodal distribution of deuterium at around 80 GPa. At the transition pressure, a significant narrowing of the peak widths of 110 is also observed, attributed to the structural relaxation by the change of elastic properties.

Abstract Hydrogen (H) is considered to be one of the candidates for light elements in the Earth’s core, but the amount and timing of delivery have been unknown. We investigated the effects of sulfur (S), another candidate element in the core, on deuteration of iron (Fe) in iron–silicate–water system up to 6–12 GPa, ~ 1200 K using in situ neutron diffraction measurements. The sample initially contained saturated water (D2O) as Mg(OD)2 in the ideal composition (Fe–MgSiO3–D2O) of the primitive Earth. In the existence of water and sulfur, phase transitions of Fe, dehydration of Mg(OD)2, and formation of iron sulfide (FeS) and silicates occurred with increasing temperature. The deuterium (D) solubility (x) in iron deuterides (FeD x ) increased with temperature and pressure, resulting in a maximum of x = 0.33(4) for the hydrous sample without S at 11.2 GPa and 1067 K. FeS was hardly deuterated until Fe deuteration had completed. The lower D concentrations in the S-containing system do not exceed the miscibility gap (x

Hydrogen bond symmetrisation is the phenomenon where a hydrogen atom is located at the centre of a hydrogen bond. Theoretical studies predict that hydrogen bonds in ice VII eventually undergo symmetrisation upon increasing pressure, involving nuclear quantum effect with significant isotope effect and drastic changes in the elastic properties through several intermediate states with varying hydrogen distribution. Despite numerous experimental studies conducted, the location of hydrogen and hence the transition pressures reported up to date remain inconsistent. Here we report the atomic distribution of deuterium in D2O ice using neutron diffraction above 100 GPa and observe the transition from a bimodal to a unimodal distribution of deuterium at around 80 GPa. At the transition pressure, a significant narrowing of the peak widths of 110 is also observed, attributed to the structural relaxation by the change of elastic properties. Atomic distribution in high-pressure water ice are directly observed, via neutron powder structure analysis, found hydrogen bonds become symmetric at pressures about 80 GPa, marking the transition from ice VII to ice X. [ABSTRACT FROM AUTHOR]

Metastable cubic ice has been identified in several conditions relevant to geo and astrochemistry, but was always characterized by stacking disorder. Here the authors synthesize a hydrogen hydrate and degas hydrogen, obtaining pure non-defected cubic ice, observed by X-ray and neutron diffraction.

Abstract Hexagonal close-packed iron hydride, hcp FeH x , is absent from the conventional phase diagram of the Fe–H system, although hcp metallic Fe exists stably over extensive temperature (T) and pressure (P) conditions, including those corresponding to the Earth’s inner core. In situ X-ray and neutron diffraction measurements at temperatures ranging from 298 to 1073 K and H pressures ranging from 4 to 7 GPa revealed that the hcp hydride was formed for FeH x compositions when x

The Earth’s core has lower density than pure iron and many studies have looked into which light elements may be present. The authors here carry outin situhigh pressure and temperature neutron experiments indicating that hydrogen may have been the first light element to dissolve into the iron core.

The structure of hydrous amorphous SiO2 is fundamental in order to investigate the effects of water on the physicochemical properties of oxide glasses and magma. The hydrous SiO2 glass with 13 wt.% D2O was synthesized under high-pressure and high-temperature conditions and its structure was investigated by small angle X-ray scattering, X-ray diffraction, and neutron diffraction experiments at pressures of up to 10 GPa and room temperature. This hydrous glass is separated into two phases: a major phase rich in SiO2 and a minor phase rich in D2O molecules distributed as small domains with dimensions of less than 100 Å. Medium-range order of the hydrous glass shrinks compared to the anhydrous SiO2 glass by disruption of SiO4 linkage due to the formation of Si−OD deuterioxyl, while the response of its structure to pressure is almost the same as that of the anhydrous SiO2 glass. Most of D2O molecules are in the small domains and hardly penetrate into the void space in the ring consisting of SiO4 tetrahedra.

The structure refinement of black phosphorus was performed at pressures of up to 3.2 GPa at room temperature by powder neutron diffraction techniques. The bond lengths and bond angles between the phosphorus atoms at pressures were precisely determined and confirmed to be consistent with those of the previous single crystal x-ray analysis [A. Brown and S. Rundqvist, Acta Cryst. 19, 684 (1965)]. Although the lattice parameters exhibited an anisotropic compressibility, the covalent P1–P2 and P1–P3 bond lengths were almost independent of pressure and only the P3–P1–P2 bond angle was reduced significantly. On the basis of our results, the significant discrepancy in the bond length reported by Cartz et al. [J. Chem. Phys. 71, 1718 (1979)] has been resolved. Our structural data will contribute to the elucidation of the Dirac semimetal state of black phosphorus under high pressure. [ABSTRACT FROM AUTHOR]

The density of the Earth's core is several percent lower than that of iron-nickel alloy under conditions of pressure and temperature equivalent to the Earth's core. Hydrogen is one of the most promising constituents accounting for the density deficit, but hydrogen occupation sites and density decrease of iron-nickel alloy caused by hydrogenation have never been investigated. In this study, the phase relation and crystal structure of Fe0.9Ni0.1Hx(Dx) at high pressures and temperatures up to 12 GPa and 1000 K were clarified by in situ X-ray diffraction and neutron diffraction measurements. Under the P-T conditions of the present study, no deuterium atoms occupied tetragonal (T) sites of face-centered cubic (fcc) Fe0.9Ni0.1Dx, although the T-site occupation was previously reported for fcc FeHx(Dx). The deuterium-induced volume expansion per deuterium vD was determined to be 2.45(4) and 3.31(6) Å3 for fcc and hcp Fe0.9Ni0.1Dx, respectively. These vD values are significantly larger than the corresponding values for FeDx. The vD value for fcc Fe0.9Ni0.1Dx slightly increases with increasing temperature. This study suggests that only 10% of nickel in iron drastically changes the behaviors of hydrogen in metal. Assuming that vD is constant regardless of pressure, the maximum hydrogen content in the Earth's inner core is estimated to be one to two times the amount of hydrogen in the oceans. [ABSTRACT FROM AUTHOR]

OBJETIVO: Identificar as causas associadas de morte e o número de causas informadas nas declarações de óbito por doenças cerebrovasculares entre residentes no Estado do Paraná. MATERIAL E MÉTODOS: O banco de dados de mortalidade do ano de 2004 foi obtido do Sistema de Informação de Mortalidade disponível no endereço eletrônico do Datasus. A população escolhida foi separada pelo programa TabWin e as causas múltiplas foram processadas pelo programa Tabulador de Causas Múltiplas de Morte. RESULTADOS: O número médio de causas informadas foi de 2,92 para as mulheres e 2,97 para os homens. A maioria dos óbitos (74,8%) foi de pessoas com 65 anos ou mais de idade. Entre as causas associadas aos óbitos por doenças cerebrovasculares se destacaram as doenças do aparelho respiratório (37,9%), as doenças hipertensivas (37,5%) e os sintomas, sinais e achados anormais de exames clínicos e de laboratório (32,3%). CONSIDERAÇÕES FINAIS: Foi observada relativa melhora na qualidade dos dados de mortalidade em relação ao número de causas citadas. A hipertensão arterial como uma das principais causas associadas sugere a necessidade do seu controle no combate à mortalidade por doenças cerebrovasculares. Incentivos devem ser promovidos para estudos com causas múltiplas, para que se utilizem melhor informações tão importantes, que são desprezadas em estudos de mortalidade feitos somente com a causa básica de morte.OBJECTIVE: To identify associated causes and the number of causes on death certificates that reported cerebrovascular diseases as the underlying cause among residents of the State of Paraná, in Brazil. METHODS: Mortality data in 2004 were obtained on the Datasus website. The population was selected by the TabWin program and multiple causes were processed by the Multiple Causes of Death Tabulator program. RESULTS: The mean number of causes listed on death certificates was 2.92 for women and 2.97 for men. Most people who died (74.8%) were aged 65 or older. Among the major causes associated with cerebrovascular disease deaths were respiratory diseases (37.9%), hypertensive diseases (37.5%), and symptoms, signs and abnormal clinical and laboratory tests (32.3%). FINAL CONSIDERATIONS: There was a relative improvement in the quality of mortality data regarding the number of causes registered. Hypertension as a major associated cause suggests the need for its control in the fight against mortality caused by cerebrovascular disease. Studies with multiple causes should be encouraged, taking into account all causes listed on death certificates, many of which are overlooked in mortality studies that only use the underlying cause of death.

A mortalidade por doença cerebrovascular foi analisada, no Paraná, Brasil, em 2007, segundo residência e local de ocorrência do óbito, pelo Sistema de Informações sobre Mortalidade (SIM). Dos óbitos de pessoas com 65 anos e mais e de 45 a 64, 17,6% e 29,8%, respectivamente, ocorreram nos domicílios. Houve associação da residência e escolaridade menor que três anos (OR = 3,96), de quatro a sete anos (OR = 1,75) e raça/cor não branca (OR = 1,39). O local do óbito foi associado com idade acima de 65 anos (OR = 1,69); escolaridade menor que três anos (OR = 1,70); e residência em municípios não sede de Regional de Saúde (OR = 1,33). Os resultados indicaram desigualdades no acesso ao hospital no momento do óbito por doença cerebrovascular, segundo residência e variáveis indicativas de situação socioeconômica. Destacou-se o SIM como fonte de dados para subsidiar ações e políticas públicas. Estudos adicionais são necessários para avaliar os fatores que influenciam no atendimento ao paciente com doença cerebrovascular, e para verificar se o mesmo perfil se repete na mortalidade por outras causas.This study analyzed stroke mortality in Paraná State, Brazil, in 2007, according to residence and place of death, using the official Mortality Information System. For deaths in individuals 65 years and older and from 45 to 64 years of age, 17.6% and 29.8%, respectively, occurred at home. An association was observed between region of residence and less than three years of schooling (OR = 3.96) four to seven years of schooling (OR = 1.75), and race or skin color (non-white: OR = 1.39). Place of death was associated with age over 65 (OR= 1.69), less than three years of schooling (OR = 1.70), and residence in municipalities other than the respective headquarters of the Regional Health offices (OR = 1.33). The results suggested inequalities in access to hospital care at the time of death from stroke, according to region of residence and socioeconomic variables. The study supports use of the Mortality Information System as a data source to back public health policies and interventions. Further studies are needed to evaluate the factors that influence quality of patient care for stroke and to verify whether the same pattern is repeated in mortality from other causes.

The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.

Estudo descritivo, desenvolvido junto a seis mães de crianças com leucemia, internadas em um hospital especializado, com o objetivo de conhecer quem são as crianças atendidas no serviço e identificar como as mães percebem a experiência de cuidar no domicílio e como elas avaliam as orientações recebidas para este cuidado. Os resultados revelaram que apesar das dúvidas, dificuldades e conflitos no interior da família, as mães cuidam com desvelo e se sentem bem em poder fazer isto, e buscam na religiosidade forças para enfrentar a situação. Observou-se ainda que elas sentem necessidade de maior interação com a equipe de enfermagem e que não se sentem à vontade para expressar expectativas ou questionamentos, mesmo quando não compreendem as orientações, revelando a existência de lacunas no âmbito da função educativa-assistencial dos profissionais enfermeiros, como subsídio para atuação da mãe/cuidadora no contexto domiciliar.Se trata de un estudio descriptivo, desarrollado con seis madres de niños con leucemia, internadas en un hospital especializado, con el objetivo de conocer quiénes son los niños atendidos en el servicio e identificar cómo perciben las madres la experiencia de cuidar en el domicilio y cómo evalúan las orientaciones recibidas para este cuidado. Los resultados revelaron que a pesar de las dudas, dificultades y conflictos en el interior de la familia, las madres cuidan con desvelo y se sienten bien de poder hacer esto, y buscan en la religiosidad fuerzas para enfrentar la situación. Además se observó que ellas sienten necesidad de más interacción con el equipo de enfermería y que no se sienten cómodas para expresar expectativas o cuestionamientos, aun cuando no comprenden las orientaciones, revelando la existencia de lagunas en el ámbito de la función educativa-asistencial de los profesionales enfermeros, como subsidio para la actuación de la madre/cuidadora en el contexto domiciliario.This is a descriptive study carried out with six mothers of children suffering from leukemia admitted to a specialized hospital. The objective of the study was to find out who the children being treated in this service are and to identify how mothers perceive the experience of caring for their child at home and how they evaluate the orientation they receive for this type of care. The results revealed that, in spite of doubts, difficulties and conflicts within the family, mothers care for their children with selflessness and feel positive about doing so, resorting to religion to get strength to face the situation. It was also observed that mothers feel a need for further interaction with the nursing staff, but do not feel at ease to express their expectations and questions, even at times when they do not understand the orientations. This is an indication of serious gaps regarding the nursing professional's function of providing assistance and educational support to the mother/caregiver within the family context.