Here we report on the spontaneous assembly of Ti
3
C
2
T
x
MXene flakes into monolayer films at the liquid-air interface. According to X-ray reflectivity and grazing incidence X-ray fluorescence both ...the structure of the layers and assembly kinetics depends on the pH value of the solution. At pH > 4 MXene flakes form a single ∼1.5 nm thick layer carrying a negative charge, while in the acidic medium the layer contains coordinated anions with the formation of the Br
aq
−
/Ti
3
C
2
T
x
/subphase interface. The surface layer compression allows the assembling of MXene flakes into a dense monolayer films with the surface coverage of up to 96% and surface pressure exceeding 40 mN m
−1
in the case of the acidic subphase. The films can readily be transferred onto solid substrates by the conventional Langmuir-Blodgett approach or modified by surfactants to form MXene/surfactant composite films.
Here we report on the spontaneous assembly of Ti
3
C
2
T
x
MXene flakes into monolayer films at the liquid-air interface.
Neste trabalho é feita uma análise do problema inicialmente discutido por S. Strogatz que trata da relação amorosa entre duas pessoas por meio de um sistema dinâmico. Para tanto, faz-se uma discussão ...dos conceitos e ferramentas básicas da teoria de Sistemas Dinâmicos essenciais para a análise proposta. Investiga-se o comportamento assintótico do sistema para os valores dos parâmetros correspondentes aos casos em que se tem "sentimentos opostos" e "personalidades opostas" de acordo com a interpretação dada ao sistema a fim de discutir a questão "os opostos se atraem?". Discute-se também a situação em que o casal sofre influência de um agente externo cuja dinâmica é governada por uma equação não-linear. Como resultado, obtém-se os planos de fase para as várias situações consideradas bem como a função hamiltoniana para os casos de centros e selas. Conclui-se citando alguns problemas físicos que são descritos por equações semelhantes.
This intellectual biography of Lev Shternberg (1861-1927) illuminates the development of professional anthropology in late imperial and early Soviet Russia. Shortly after the formation of the Soviet ...Union the government initiated a detailed ethnographic survey of the country's peoples. Lev Shternberg, who as a political exile during the late tsarist period had conducted ethnographic research in northeastern Siberia, was one of the anthropologists who directed this survey and consequently played a major role in influencing the professionalization of anthropology in the Soviet Union.
But Shternberg was much more than a government anthropologist. Under the new regime he continued his work as the senior curator of the St. Petersburg Museum of Anthropology and Ethnography, which began in the early 1900s. In the last decade of his life Shternberg also played a leading role in establishing a new Soviet school of cultural anthropology and in training a cohort of professional anthropologists. True to the ideals of his youth, he also continued an active involvement in the intellectual life of the Jewish community, even though the new regime was making it increasingly difficult.
This in-depth biography explores the scholarly and political aspects of Shternberg's life and how they influenced each other. It also places his career in both national and international perspectives, showing the context in which he lived and worked and revealing the important developments in Russian anthropology during these tumultuous years.
As mortality rates decline, life expectancy increases, and populations age, non-fatal outcomes of diseases and injuries are becoming a larger component of the global burden of disease. The Global ...Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) provides a comprehensive assessment of prevalence, incidence, and years lived with disability (YLDs) for 328 causes in 195 countries and territories from 1990 to 2016.
We estimated prevalence and incidence for 328 diseases and injuries and 2982 sequelae, their non-fatal consequences. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between incidence, prevalence, remission, and cause of death rates for each condition. For some causes, we used alternative modelling strategies if incidence or prevalence needed to be derived from other data. YLDs were estimated as the product of prevalence and a disability weight for all mutually exclusive sequelae, corrected for comorbidity and aggregated to cause level. We updated the Socio-demographic Index (SDI), a summary indicator of income per capita, years of schooling, and total fertility rate. GBD 2016 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER).
Globally, low back pain, migraine, age-related and other hearing loss, iron-deficiency anaemia, and major depressive disorder were the five leading causes of YLDs in 2016, contributing 57·6 million (95% uncertainty interval UI 40·8–75·9 million 7·2%, 6·0–8·3), 45·1 million (29·0–62·8 million 5·6%, 4·0–7·2), 36·3 million (25·3–50·9 million 4·5%, 3·8–5·3), 34·7 million (23·0–49·6 million 4·3%, 3·5–5·2), and 34·1 million (23·5–46·0 million 4·2%, 3·2–5·3) of total YLDs, respectively. Age-standardised rates of YLDs for all causes combined decreased between 1990 and 2016 by 2·7% (95% UI 2·3–3·1). Despite mostly stagnant age-standardised rates, the absolute number of YLDs from non-communicable diseases has been growing rapidly across all SDI quintiles, partly because of population growth, but also the ageing of populations. The largest absolute increases in total numbers of YLDs globally were between the ages of 40 and 69 years. Age-standardised YLD rates for all conditions combined were 10·4% (95% UI 9·0–11·8) higher in women than in men. Iron-deficiency anaemia, migraine, Alzheimer's disease and other dementias, major depressive disorder, anxiety, and all musculoskeletal disorders apart from gout were the main conditions contributing to higher YLD rates in women. Men had higher age-standardised rates of substance use disorders, diabetes, cardiovascular diseases, cancers, and all injuries apart from sexual violence. Globally, we noted much less geographical variation in disability than has been documented for premature mortality. In 2016, there was a less than two times difference in age-standardised YLD rates for all causes between the location with the lowest rate (China, 9201 YLDs per 100 000, 95% UI 6862–11943) and highest rate (Yemen, 14 774 YLDs per 100 000, 11 018–19 228).
The decrease in death rates since 1990 for most causes has not been matched by a similar decline in age-standardised YLD rates. For many large causes, YLD rates have either been stagnant or have increased for some causes, such as diabetes. As populations are ageing, and the prevalence of disabling disease generally increases steeply with age, health systems will face increasing demand for services that are generally costlier than the interventions that have led to declines in mortality in childhood or for the major causes of mortality in adults. Up-to-date information about the trends of disease and how this varies between countries is essential to plan for an adequate health-system response.
Bill & Melinda Gates Foundation, and the National Institute on Aging and the National Institute of Mental Health of the National Institutes of Health.
Anxiety disorders are common, complex psychiatric disorders with twin heritabilities of 30-60%. We conducted a genome-wide association study of Lifetime Anxiety Disorder (n
= 25 453, n
= 58 113) ...and an additional analysis of Current Anxiety Symptoms (n
= 19 012, n
= 58 113). The liability scale common variant heritability estimate for Lifetime Anxiety Disorder was 26%, and for Current Anxiety Symptoms was 31%. Five novel genome-wide significant loci were identified including an intergenic region on chromosome 9 that has previously been associated with neuroticism, and a locus overlapping the BDNF receptor gene, NTRK2. Anxiety showed significant positive genetic correlations with depression and insomnia as well as coronary artery disease, mirroring findings from epidemiological studies. We conclude that common genetic variation accounts for a substantive proportion of the genetic architecture underlying anxiety.
Numerous reports of vascular events after an initial recovery from COVID-19 form our impetus to investigate the impact of COVID-19 on vascular health of recovered patients. We found elevated levels ...of circulating endothelial cells (CECs), a biomarker of vascular injury, in COVID-19 convalescents compared to healthy controls. In particular, those with pre-existing conditions (e.g., hypertension, diabetes) had more pronounced endothelial activation hallmarks than non-COVID-19 patients with matched cardiovascular risk. Several proinflammatory and activated T lymphocyte-associated cytokines sustained from acute infection to recovery phase, which correlated positively with CEC measures, implicating cytokine-driven endothelial dysfunction. Notably, we found higher frequency of effector T cells in our COVID-19 convalescents compared to healthy controls. The activation markers detected on CECs mapped to counter receptors found primarily on cytotoxic CD8
T cells, raising the possibility of cytotoxic effector cells targeting activated endothelial cells. Clinical trials in preventive therapy for post-COVID-19 vascular complications may be needed.
Tissue wounding induces the rapid recruitment of leukocytes. Wounds and tumours--a type of 'unhealed wound'--generate hydrogen peroxide (H(2)O(2)) through an NADPH oxidase (NOX). This extracellular ...H(2)O(2) mediates recruitment of leukocytes, particularly the first responders of innate immunity, neutrophils, to injured tissue. However, the sensor that neutrophils use to detect the redox state at wounds is unknown. Here we identify the Src family kinase (SFK) Lyn as a redox sensor that mediates initial neutrophil recruitment to wounds in zebrafish larvae. Lyn activation in neutrophils is dependent on wound-derived H(2)O(2) after tissue injury, and inhibition of Lyn attenuates neutrophil wound recruitment. Inhibition of SFKs also disrupted H(2)O(2)-mediated chemotaxis of primary human neutrophils. In vitro analysis identified a single cysteine residue, C466, as being responsible for direct oxidation-mediated activation of Lyn. Furthermore, transgenic-tissue-specific reconstitution with wild-type Lyn and a cysteine mutant revealed that Lyn C466 is important for the neutrophil wound response and downstream signalling in vivo. This is the first identification, to our knowledge, of a physiological redox sensor that mediates leukocyte wound attraction in multicellular organisms.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background Non-fatal outcomes of disease and injury increasingly detract from the ability of the world's population to live in full health, a trend largely attributable to an epidemiological ...transition in many countries from causes affecting children, to non-communicable diseases (NCDs) more common in adults. For the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015), we estimated the incidence, prevalence, and years lived with disability for diseases and injuries at the global, regional, and national scale over the period of 1990 to 2015. Methods We estimated incidence and prevalence by age, sex, cause, year, and geography with a wide range of updated and standardised analytical procedures. Improvements from GBD 2013 included the addition of new data sources, updates to literature reviews for 85 causes, and the identification and inclusion of additional studies published up to November, 2015, to expand the database used for estimation of non-fatal outcomes to 60 900 unique data sources. Prevalence and incidence by cause and sequelae were determined with DisMod-MR 2.1, an improved version of the DisMod-MR Bayesian meta-regression tool first developed for GBD 2010 and GBD 2013. For some causes, we used alternative modelling strategies where the complexity of the disease was not suited to DisMod-MR 2.1 or where incidence and prevalence needed to be determined from other data. For GBD 2015 we created a summary indicator that combines measures of income per capita, educational attainment, and fertility (the Socio-demographic Index SDI) and used it to compare observed patterns of health loss to the expected pattern for countries or locations with similar SDI scores. Findings We generated 9·3 billion estimates from the various combinations of prevalence, incidence, and YLDs for causes, sequelae, and impairments by age, sex, geography, and year. In 2015, two causes had acute incidences in excess of 1 billion: upper respiratory infections (17·2 billion, 95% uncertainty interval UI 15·4–19·2 billion) and diarrhoeal diseases (2·39 billion, 2·30–2·50 billion). Eight causes of chronic disease and injury each affected more than 10% of the world's population in 2015: permanent caries, tension-type headache, iron-deficiency anaemia, age-related and other hearing loss, migraine, genital herpes, refraction and accommodation disorders, and ascariasis. The impairment that affected the greatest number of people in 2015 was anaemia, with 2·36 billion (2·35–2·37 billion) individuals affected. The second and third leading impairments by number of individuals affected were hearing loss and vision loss, respectively. Between 2005 and 2015, there was little change in the leading causes of years lived with disability (YLDs) on a global basis. NCDs accounted for 18 of the leading 20 causes of age-standardised YLDs on a global scale. Where rates were decreasing, the rate of decrease for YLDs was slower than that of years of life lost (YLLs) for nearly every cause included in our analysis. For low SDI geographies, Group 1 causes typically accounted for 20–30% of total disability, largely attributable to nutritional deficiencies, malaria, neglected tropical diseases, HIV/AIDS, and tuberculosis. Lower back and neck pain was the leading global cause of disability in 2015 in most countries. The leading cause was sense organ disorders in 22 countries in Asia and Africa and one in central Latin America; diabetes in four countries in Oceania; HIV/AIDS in three southern sub-Saharan African countries; collective violence and legal intervention in two north African and Middle Eastern countries; iron-deficiency anaemia in Somalia and Venezuela; depression in Uganda; onchoceriasis in Liberia; and other neglected tropical diseases in the Democratic Republic of the Congo. Interpretation Ageing of the world's population is increasing the number of people living with sequelae of diseases and injuries. Shifts in the epidemiological profile driven by socioeconomic change also contribute to the continued increase in years lived with disability (YLDs) as well as the rate of increase in YLDs. Despite limitations imposed by gaps in data availability and the variable quality of the data available, the standardised and comprehensive approach of the GBD study provides opportunities to examine broad trends, compare those trends between countries or subnational geographies, benchmark against locations at similar stages of development, and gauge the strength or weakness of the estimates available. Funding Bill & Melinda Gates Foundation.
We report on the specific properties of O- and OH-terminated Ti3C2Tx nanosheets contributing the permeance of MXene membranes with sorption type selectivity. Thin MXene selective layers on porous ...support demonstrated separation factor for NH3/H2 pair over 50 with ammonia permeance up to 5.0 m3(STP)∙m−2∙bar−1∙h−1 facilitated for humid medium and separation factor for H2O/N2 over 1000 with water permeance over 30 m3(STP)∙m−2∙bar−1∙h−1 close to P0(H2O). According to QCM and GIWAXS studies, high permeance and selectivity of membranes towards ammonia and water vapors are attributed both to ultimate sorption capacity for “basic” vapors and condensation-induced expansion of the interlayer space. Sorption capacity of MXene over 0.045 g∙g(MXene)−1 at 0.3P0 for both NH3 and H2O, significantly exceeds the sorption capacity for permanent gases. Calculations of the diffusion coefficient suggest labyrinthine transport of vapors. For permanent gases no variation of diffusion coefficients was observed with feed pressure, indicating Knudsen diffusion mechanism. Diffusion coefficient of strongly absorbed gases significantly increases with pressure. According to GIWAXS the effect was attributed to the increase of the interlayer distance with saturation of membrane with vapors and reduction of activation barriers for hopping diffusion. Demonstrated characteristics of Ti3C2Tx nanosheets makes it a promising candidate for developing of ammonia selective membranes for Haber-Bosch process membrane extractors.
Display omitted
•Acidic properties of OH groups on MXene surface determine affinity to “basic” gases.•NH3 sorption coefficient attains 52 mmol/(m3·Pa), drastically exceed sorption for other gases.•Membranes with Ti3C2Tx selective layer were obtained by spin-coating technique.•Selectivity for a NH3/H2 exceeds 50 with ammonia permeance up to 3.91 m3 m−2 bar−1∙h−1.•The increase of interlayer distance with MXene saturation with vapors was founded.
PDF
