415 research outputs found
Quantum oscillations of nitrogen atoms in uranium nitride
The vibrational excitations of crystalline solids corresponding to acoustic
or optic one phonon modes appear as sharp features in measurements such as
neutron spectroscopy. In contrast, many-phonon excitations generally produce a
complicated, weak, and featureless response. Here we present time-of-flight
neutron scattering measurements for the binary solid uranium nitride (UN),
showing well-defined, equally-spaced, high energy vibrational modes in addition
to the usual phonons. The spectrum is that of a single atom, isotropic quantum
harmonic oscillator and characterizes independent motions of light nitrogen
atoms, each found in an octahedral cage of heavy uranium atoms. This is an
unexpected and beautiful experimental realization of one of the fundamental,
exactly-solvable problems in quantum mechanics. There are also practical
implications, as the oscillator modes must be accounted for in the design of
generation IV nuclear reactors that plan to use UN as a fuel.Comment: 25 pages, 10 figures, submitted to Nature Communications,
supplementary information adde
Towards condom skills: a cross-sectional study of the association between condom proficiency, condom problems and STI risk amongst MSM
<p>Abstract</p> <p>Background</p> <p>Condom use problems are common amongst Scotland’s men who have sex with men (MSM). To date condom errors have been associated with the likelihood of sexually transmitted infections in heterosexual sexually transmitted infection (STI) clinic attendees but not in MSM and direct evidence of a link between condom problems and STI acquisition in MSM have been lacking. This study investigated the possibility of an independent association between condom proficiency, condom problems and STI acquisition in MSM in Scotland.</p> <p>Methods</p> <p>An exploratory observational design employed cross-sectional surveys in both STI clinic and community settings. Respondents completed self-report measures of socio-demographic variables, scales of condom proficiency and condom problems and numbers of different partners with whom men have had unprotected anal intercourse (UAI partners) in the preceding year. Self-report data was corroborated with clinical STI diagnosis where possible. Analysis included chi-squared and Mann–Whitney tests and multiple logistic regression.</p> <p>Results</p> <p>792 respondents provided data with an overall response rate of 70% (n = 459 clinic sample, n = 333 community sample). Number of UAI partners was the strongest predictor of self-reported STI acquisition over the previous 12 months (p < 0.001 in both clinic and community samples). Demographic characteristics were not associated with self-reported STI diagnosis. However, condom proficiency score was associated with self-reported STI acquisition (p < 0.05 in both samples). Condom problem score was also associated with self-reported STI diagnosis in the clinic (p = 0.001) but not the community sample. Condom problem score remained associated with self-reported STI diagnosis in the clinic sample after adjusting for number of UAI partners with logistic regression.</p> <p>Conclusions</p> <p>This exploratory study highlights the potential importance of targeted condom use skills interventions amongst MSM. It demands further research examining the utility of condom problem measures in wider populations, across prospective and experimental research designs, and a programme of research exploring their feasibility as a tool determining candidacy for brief interventions.</p
Migration and social mobility between Argentina and Spain : climbing the social hierarchy in the transnational space
Production of INCASI Project H2020-MSCA-RISE-2015 GA 691004This chapter analyses the relationship between migration and social mobility in Argentina and Spain from a transnational perspective focusing on two dimensions: the patterns of intergenerational social mobility of immigrants and natives in both countries; the social mobility strategies and trajectories of Galicians families in Buenos Aires and Argentinians, of Galician origin, who migrated to Galicia after the 2001 crisis. The chapter begins by contextualizing the migratory trends in Europe and Latin America. This is followed by a comparative study of how immigration impacts on the class structure and social mobility patterns in Argentina and Spain. Quantitative analysis techniques are used to study the intergenerational social mobility rates. The statistical analysis of stratification and social mobility surveys have been benchmarked against previous studies conducted in Argentina (Germani, G., Movilidad social en la sociedad industrial. EUDEBA, Buenos Aires, 1963; Dalle, P., Movilidad social desde las clases populares. Un estudio sociológico en el Área Metropolitana de Buenos Aires (1960-2013). CLACSO/Instituto de Investigaciones Gino Germani-UBA/CICCUS, Buenos Aires, 2016) and Spain (Fachelli, S., & López-Roldán, P., Revista Española de Sociología 26:1-20, 2017). Secondly, qualitative research methods are used to consider the social mobility strategies and class trajectories of migrant families. We analyse two fieldworks, developed in the framework of other research projects (based on 44 biographical and semi-structured interviews). These case studies were carried out with Galicians that migrated to Argentina between 1940 and 1960 and Argentinians, of Galician origin, who migrated to Galicia after the 2001 crisis
Drug Repurposing: Far Beyond New Targets for Old Drugs
Repurposing drugs requires finding novel therapeutic indications compared to the ones for which they were already approved. This is an increasingly utilized strategy for finding novel medicines, one that capitalizes on previous investments while derisking clinical activities. This approach is of interest primarily because we continue to face significant gaps in the drug–target interactions matrix and to accumulate safety and efficacy data during clinical studies. Collecting and making publicly available as much data as possible on the target profile of drugs offer opportunities for drug repurposing, but may limit the commercial applications by patent applications. Certain clinical applications may be more feasible for repurposing than others because of marked differences in side effect tolerance. Other factors that ought to be considered when assessing drug repurposing opportunities include relevance to the disease in question and the intellectual property landscape. These activities go far beyond the identification of new targets for old drugs
Colouration and Colour Changes of the Fiddler Crab, Uca capricornis: A Descriptive Study
Colour changes in animals may be triggered by a variety of social and environmental factors and may occur over a matter of seconds or months. Crustaceans, like fiddler crabs (genus Uca), are particularly adept at changing their colour and have been the focus of numerous studies. However, few of these studies have attempted to quantitatively describe the individual variation in colour and pattern or their adaptive significance. This paper quantitatively describes the colour patterns of the fiddler crab Uca capricornis and their ability to change on a socially significant timescale. The most dramatic changes in colour pattern are associated with moulting. These ontogenetic changes result in a general reduction of the colour pattern with increasing size, although females are more colourful and variable than similarly-sized males. Uca capricornis are also capable of rapid colour changes in response to stress, but show no endogenous rhythms associated with the semilunar and tidal cycles commonly reported in other fiddler crabs. The extreme colour polymorphism and the relative stability of the colour patterns in Uca capricornis are consistent with their use in visually mediated mate recognition
Cardiovascular and hormonal responses to static handgrip in young and older healthy men
The purpose of this study was to investigate the effect of age on cardiovascular changes and plasma concentrations of adrenomedullin (ADM), catecholamines, endothelin-1 (ET-1) and plasma renin activity (PRA) in healthy men. A total of 15 young (21 ± 0.3 years) and 15 older (64 ± 0.7 years) healthy men performed two 3-min bouts of static handgrip at 30% of maximal voluntary contraction, alternately with each hand without any break between the bouts. During exercise heart rate (HR), blood pressure (BP), stroke volume (SV) and pre-ejection period (PEP) and left ventricle ejection time (LVET) were measured. Blood samples were taken before exercise, at the end of both exercise bouts and in the fifth minute of the recovery period. The handgrip-induced increases in HR and cardiac output were significantly smaller in older than in young men (p < 0.01). SV decreased only in older men (p < 0.001). There were no differences between groups in BP increases. The baseline plasma ADM and catecholamines were higher in older man compared to young subjects. Handgrip caused increases in plasma ADM, ET-1 and PRA only in older men (p < 0.05). The increases in plasma ADM correlated positively with those of noradrenaline (NA), PRA, ET-1 and LVET and negatively with changes in total peripheral resistance (TPR), SV, PEP and PEP/LVET ratio. The increases in plasma ET-1 correlated positively with those of NA, PRA, TPR, mean BP and SV. These results revealed that ADM, ET-1 and angiotensin II can contribute to maintain vascular tone during static exercise in older but not in younger men
Inhibitor of cyclooxygenase-2 induces cell-cycle arrest in the epithelial cancer cell line via up-regulation of cyclin dependent kinase inhibitor p21
Cyclooxygenase-2 is the rate-limiting enzyme in synthesis of prostaglandins and other eicosanoids. Prior reports have shown that inhibition of cyclooxygenase-2 activity, either by selective inhibitors or by antisense oligonucleotide, results in suppression of growth of squamous cell carcinoma cell lines which express high cyclooxygenase-2 levels, such as NA, a cell line established from a squamous cell carcinoma of the tongue. To investigate the mechanisms by which cyclooxygenase-2 inhibitors suppressed growth of these cells, the effects of NS-398, the selective cyclooxygenase-2 inhibitor, on cell-cycle distribution were examined. NS-398 induced G0/G1 cell-cycle arrest in NA cells which expressed cyclooxygenase-2. G0/G1 arrest induced by NS-398 was accompanied by up-regulation of cyclin-dependent kinase inhibitor p21, but not by up-regulation of the other cyclin-dependent kinase inhibitors. Transfection with p21 antisense oligonucleotide inhibited cell-cycle arrest induced by NS-398. Accumulation in G0/G1 was also observed in NA cells transfected with cyclooxygenase-2 antisense oligonucleotide. On the other hand, NS-398-treated NA cells showed a loss of plasma membrane asymmetry, a marker of early events in apoptosis. However, NS-398 did not induce other morphological and biochemical changes related to apoptotic cell death. These results suggest that cyclooxygenase-2 inhibitor induces G0/G1 cell-cycle arrest in NA cells by up-regulation of p21. Our results also suggest that NS-398 is not sufficient to complete the whole process of apoptosis in NA cells, although it induces an early event in apoptosis
HBV Infection in Relation to Consistent Condom Use: A Population-Based Study in Peru
Data on hepatitis B virus (HBV) prevalence are limited in developing countries. There is also limited information of consistent condom use efficacy for reducing HBV transmission at the population level. The study goal was to evaluate the prevalence and factors associated with HBV infection in Peru, and the relationship between anti-HBc positivity and consistent condom use.Data from two different surveys performed in 28 mid-sized Peruvian cities were analyzed. Participants aged 18-29 years were selected using a multistage cluster sampling. Information was collected through a validated two-part questionnaire. The first part (face-to-face) concerned demographic data, while the second part (self-administered using handheld computers) concerned sexual behavior. Hepatitis B core antibody (anti-HBc) was tested in 7,000 blood samples. Prevalences and associations were adjusted for sample strata, primary sampling units and population weights. Anti-HBc prevalence was 5.0% (95%CI 4.1%-5.9%), with the highest prevalence among jungle cities: 16.3% (95%CI 13.8%-19.1%). In the multivariable analysis, Anti-HBc positivity was directly associated with geographic region (highlands OR = 2.05; 95%CI 1.28-3.27, and jungle OR = 4.86; 95%CI 3.05-7.74; compared to coastal region); and inversely associated with age at sexual debut (OR = 0.90; 95%CI 0.85-0.97). Consistent condom use, evaluated in about 40% of participants, was associated with reduced prevalence (OR = 0.34; 95%CI 0.15-0.79) after adjusting for gender, geographic region, education level, lifetime number of sex partners, age at sexual debut and year of survey.Residence in highlands or jungle cities is associated with higher anti-HBc prevalences, whereas increasing age at sexual debut were associated with lower prevalences. Consistent condom use was associated with decreased risk of anti-HBc. Findings from this study emphasize the need of primary prevention programs (vaccination) especially in the jungle population, and imply that condom use promotion might be a potential strategy to prevent HBV infection
A Tale of Switched Functions: From Cyclooxygenase Inhibition to M-Channel Modulation in New Diphenylamine Derivatives
Cyclooxygenase (COX) enzymes are molecular targets of nonsteroidal anti-inflammatory drugs (NSAIDs), the most used medication worldwide. However, the COX enzymes are not the sole molecular targets of NSAIDs. Recently, we showed that two NSAIDs, diclofenac and meclofenamate, also act as openers of Kv7.2/3 K+ channels underlying the neuronal M-current. Here we designed new derivatives of diphenylamine carboxylate to dissociate the M-channel opener property from COX inhibition. The carboxylate moiety was derivatized into amides or esters and linked to various alkyl and ether chains. Powerful M-channel openers were generated, provided that the diphenylamine moiety and a terminal hydroxyl group are preserved. In transfected CHO cells, they activated recombinant Kv7.2/3 K+ channels, causing a hyperpolarizing shift of current activation as measured by whole-cell patch-clamp recording. In sensory dorsal root ganglion and hippocampal neurons, the openers hyperpolarized the membrane potential and robustly depressed evoked spike discharges. They also decreased hippocampal glutamate and GABA release by reducing the frequency of spontaneous excitatory and inhibitory post-synaptic currents. In vivo, the openers exhibited anti-convulsant activity, as measured in mice by the maximal electroshock seizure model. Conversion of the carboxylate function into amide abolished COX inhibition but preserved M-channel modulation. Remarkably, the very same template let us generating potent M-channel blockers. Our results reveal a new and crucial determinant of NSAID-mediated COX inhibition. They also provide a structural framework for designing novel M-channel modulators, including openers and blockers
Corporate philanthropy, political influence, and health policy
Background The Framework Convention of Tobacco Control (FCTC) provides a basis for nation states to limit the political effects of tobacco industry philanthropy, yet progress in this area is limited. This paper aims to integrate the findings of previous studies on tobacco industry philanthropy with a new analysis of British American Tobacco's (BAT) record of charitable giving to develop a general model of corporate political philanthropy that can be used to facilitate implementation of the FCTC. Method Analysis of previously confidential industry documents, BAT social and stakeholder dialogue reports, and existing tobacco industry document studies on philanthropy. Results The analysis identified six broad ways in which tobacco companies have used philanthropy politically: developing constituencies to build support for policy positions and generate third party advocacy; weakening opposing political constituencies; facilitating access and building relationships with policymakers; creating direct leverage with policymakers by providing financial subsidies to specific projects; enhancing the donor's status as a source of credible information; and shaping the tobacco control agenda by shifting thinking on the importance of regulating the market environment for tobacco and the relative risks of smoking for population health. Contemporary BAT social and stakeholder reports contain numerous examples of charitable donations that are likely to be designed to shape the tobacco control agenda, secure access and build constituencies. Conclusions and Recommendations Tobacco companies' political use of charitable donations underlines the need for tobacco industry philanthropy to be restricted via full implementation of Articles 5.3 and 13 of the FCTC. The model of tobacco industry philanthropy developed in this study can be used by public health advocates to press for implementation of the FCTC and provides a basis for analysing the political effects of charitable giving in other industry sectors which have an impact on public health such as alcohol and food
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