291 research outputs found

    Alkyne activation and polyhedral reorganization in benzothiazolate-capped osmium clusters on reaction with diethyl acetylenedicarboxylate (DEAD) and ethyl propiolate

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    The reactivity of the face-capped benzothiazolate clusters HOs3(CO)9[Ό3-C7H3(R)NS] (1a, R = H; 1b, R = 2-CH3) with alkynes has been investigated. 1a reacts with DEAD at 67 °C to furnish the isomeric alkenyl clusters Os3(CO)9(Ό-C7H4NS)(Ό3-EtO2CCCHCO2Et) (2a and 3a). X-ray crystallographic analyses of 2a and 3a have confirmed the stereoisomeric relationship of these products and the regiospecific polyhedral expansion that follows the formal transfer of the hydride to the coordinated alkyne ligand in HOs3(CO)9(Ό-C7H4NS)(2-DEAD). The significant structural differences between the two isomers, as revealed by the solid-state structures, derives from the regiospecific cleavage of one of the three Os-Os bonds in the intermediate alkenyl cluster Os3(CO)9(Ό-C7H4NS)(1-EtO2CCCHCO2Et), which follows hydride transfer to the coordinated alkyne ligand in the pi compound HOs3(CO)9(Ό-C7H4NS)(2-DEAD). Control experiments confirm the reversibility of the reaction leading to the formation of 2a and 3a. Whereas heating either isomer in refluxing THF or benzene affords a binary mixture containing 2a and 3a, thermolysis in refluxing toluene leads to the activation of the alkenyl ligand and formation of the new cluster Os3(CO)9(Ό-C7H4NS)(Ό3-EtO2CCCH2) (4). 4 was independently synthesized from 1a and ethyl propiolate at room temperature. The computed mechanisms that account for the formation of 2a and 3a are presented, along with the mechanism for the reaction of 1a with ethyl propiolate to give 4

    Mapping the pharmacological modulation of brain oxygen metabolism:the effects of caffeine on absolute CMRO2 measured using dual calibrated fMRI

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    This study aims to map the acute effects of caffeine ingestion on grey matter oxygen metabolism and haemodynamics with a novel MRI method. Sixteen healthy caffeine consumers (8 males, age = 24.7±5.1) were recruited to this randomised, double-blind, placebo-controlled study. Each participant was scanned on two days before and after the delivery of an oral caffeine (250 mg) or placebo capsule. Our measurements were obtained with a newly proposed estimation approach applied to data from a dual calibration fMRI experiment that uses hypercapnia and hyperoxia to modulate brain blood flow and oxygenation. Estimates were based on a forward model that describes analytically the contributions of cerebral blood flow (CBF) and of the measured end-tidal partial pressures of CO2 and O2 to the acquired dual-echo GRE signal. The method allows the estimation of grey matter maps of: oxygen extraction fraction (OEF), CBF, CBF-related cerebrovascular reactivity (CVR) and cerebral metabolic rate of oxygen consumption (CMRO2). Other estimates from a multi inversion time ASL acquisition (mTI-ASL), salivary samples of the caffeine concentration and behavioural measurements are also reported. We observed significant differences between caffeine and placebo on average across grey matter, with OEF showing an increase of 15.6% (SEM ±4.9%, p <0.05) with caffeine, while CBF and CMRO2 showed differences of −30.4% (SEM ±1.6%, p <0.01) and −18.6% (SEM ±2.9%, p <0.01) respectively with caffeine administration. The reduction in oxygen metabolism found is somehow unexpected, but consistent with a hypothesis of decreased energetic demand, supported by previous electrophysiological studies reporting reductions in spectral power with EEG. Moreover the maps of the physiological parameters estimated illustrate the spatial distribution of changes across grey matter enabling us to localise the effects of caffeine with voxel-wise resolution. CBF changes were widespread as reported by previous findings, while changes in OEF were found to be more restricted, leading to unprecedented mapping of significant CMRO2 reductions mainly in frontal gyrus, parietal and occipital lobes. In conclusion, we propose the estimation framework based on our novel forward model with a dual calibrated fMRI experiment as a viable MRI method to map the effects of drugs on brain oxygen metabolism and haemodynamics with voxel-wise resolution

    A C-elegans stretch receptor neuron revealed by a mechanosensitive TRP channel homologue

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    The nematode Caenorhabditis elegans is commonly used as a genetic model organism for dissecting integration of the sensory and motor systems(1). Despite extensive genetic and behavioural analyses that have led to the identification of many genes and neural circuits involved in regulating C. elegans locomotion behaviour(1), it remains unclear whether and how somatosensory feedback modulates motor output during locomotion. In particular, no stretch receptors have been identified in C. elegans, raising the issue of whether stretch-receptor-mediated proprioception is used by C. elegans to regulate its locomotion behaviour. Here we have characterized TRP-4, the C. elegans homologue of the mechanosensitive TRPN channel. We show that trp-4 mutant worms bend their body abnormally, exhibiting a body posture distinct from that of wild-type worms during locomotion, suggesting that TRP-4 is involved in stretch-receptor-mediated proprioception. We show that TRP-4 acts in a single neuron, DVA, to mediate its function in proprioception, and that the activity of DVA can be stimulated by body stretch. DVA both positively and negatively modulates locomotion, providing a unique mechanism whereby a single neuron can fine-tune motor activity. Thus, DVA represents a stretch receptor neuron that regulates sensory - motor integration during C. elegans locomotion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62770/1/nature04538.pd

    Mechanical analysis of infant carrying in hominoids

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    In all higher nonhuman primates, species survival depends upon safe carrying of infants clinging to body hair of adults. In this work, measurements of mechanical properties of ape hair (gibbon, orangutan, and gorilla) are presented, focusing on constraints for safe infant carrying. Results of hair tensile properties are shown to be species-dependent. Analysis of the mechanics of the mounting position, typical of heavier infant carrying among African apes, shows that both clinging and friction are necessary to carry heavy infants. As a consequence, a required relationship between infant weight, hair–hair friction coefficient, and body angle exists. The hair–hair friction coefficient is measured using natural ape skin samples, and dependence on load and humidity is analyzed. Numerical evaluation of the equilibrium constraint is in agreement with the knuckle-walking quadruped position of African apes. Bipedality is clearly incompatible with the usual clinging and mounting pattern of infant carrying, requiring a revision of models of hominization in relation to the divergence between apes and hominins. These results suggest that safe carrying of heavy infants justify the emergence of biped form of locomotion. Ways to test this possibility are foreseen here

    Safety and Immunogenicity of Neonatal Pneumococcal Conjugate Vaccination in Papua New Guinean Children: A Randomised Controlled Trial

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    Background: Approximately 826,000 children, mostly young infants, die annually from invasive pneumococcal disease. A 6-10-14-week schedule of pneumococcal conjugate vaccine (PCV) is efficacious but neonatal PCV may provide earlier protection and better coverage. We conducted an open randomized controlled trial in Papua New Guinea to compare safety, immunogenicity and priming for memory of 7-valent PCV (PCV7) given in a 0-1-2-month (neonatal) schedule with that of the routine 1-2-3-month (infant) schedule. Methods: We randomized 318 infants at birth to receive PCV7 in the neonatal or infant schedule or no PCV7. All infants received 23-valent pneumococcal polysaccharide vaccine (PPV) at age 9 months. Serotype-specific serum IgG for PCV7 (VT) serotypes and non-VT serotypes 2, 5 and 7F were measured at birth and 2, 3, 4, 9, 10 and 18 months of age. Primary outcomes were geometric mean concentrations (GMCs) and proportions with concentration ≄0.35 ”g/ml of VT serotype-specific pneumococcal IgG at age 2 months and one month post-PPV.Results: We enrolled 101, 105 and 106 infants, respectively, into neonatal, infant and control groups. Despite high background levels of maternally derived antibody, both PCV7 groups had higher GMCs than controls at age 2 months for serotypes 4 (p<0.001) and 9V (p<0.05) and at age 3 months for all VTs except 6B. GMCs for serotypes 4, 9V, 18C and 19F were significantly higher (p<0.001) at age 2 months in the neonatal (one month post-dose2 PCV7) than in the infant group (one month post-dose1 PCV7). PPV induced significantly higher VT antibody responses in PCV7-primed than unprimed infants, with neonatal and infant groups equivalent. High VT and non-VT antibody concentrations generally persisted to age 18 months. Conclusions: PCV7 is well-tolerated and immunogenic in PNG neonates and young infants and induces immunologic memory to PPV booster at age 9 months with antibody levels maintained to age 18 months

    Cost-effectiveness of an integrated 'fast track' rehabilitation service for multi-trauma patients involving dedicated early rehabilitation intervention programs: design of a prospective, multi-centre, non-randomised clinical trial

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    Contains fulltext : 79649.pdf (publisher's version ) (Open Access)ABSTRACT: BACKGROUND: In conventional multi-trauma care service (CTCS), patients are admitted to hospital via the accident & emergency room. After surgery they are transferred to the IC-unit followed by the general surgery ward. Ensuing treatment takes place in a hospital's outpatient clinic, a rehabilitation centre, a nursing home or the community. Typically, each of the CTCS partners may have its own more or less autonomous treatment perspective. Clinical evidence, however, suggests that an integrated multi-trauma rehabilitation approach ('Supported Fast-track multi-Trauma Rehabilitation Service': SFTRS), featuring: 1) earlier transfer to a specialised trauma rehabilitation unit; 2) earlier start of 'non-weight-bearing' training and multidisciplinary treatment; 3) well-documented treatment protocols; 4) early individual goal-setting; 5) co-ordination of treatment between trauma surgeon and physiatrist, and 6) shorter lengths-of-stay, may be more (cost-)effective.This paper describes the design of a prospective cohort study evaluating the (cost-) effectiveness of SFTRS relative to CTCS. METHODS/DESIGN: The study population includes multi-trauma patients, admitted to one of the participating hospitals, with an Injury Severity Scale score > = 16, complex multiple injuries in several extremities or complex pelvic and/or acetabulum fractures. In a prospective cohort study CTCS and SFTRS will be contrasted. The inclusion period is 19 months. The duration of follow-up is 12 months, with measurements taken at baseline, and at 3,6,9 and 12 months post-injury.Primary outcome measures are 'quality of life' (SF-36) and 'functional health status' (Functional Independence Measure). Secondary outcome measures are the Hospital Anxiety & Depression Scale, the Mini-Mental State Examination as an indicator of cognitive functioning, and the Canadian Occupational Performance Measure measuring the extent to which individual ADL treatment goals are met. Costs will be assessed using the PROductivity and DISease Questionnaire and a cost questionnaire. DISCUSSION: The study will yield results on the efficiency of an adapted care service for multi-trauma patients (SFTRS) featuring earlier (and condensed) involvement of specialised rehabilitation treatment. Results will show whether improved SFTRS logistics, combined with shorter stays in hospital and rehabilitation clinic and specialised early rehabilitation training modules are more (cost-) effective, relative to CTCS. TRIAL REGISTRATION: Current Controlled Trials register (ISRCTN68246661) and Netherlands Trial Register (NTR139)

    Migration and social mobility between Argentina and Spain : climbing the social hierarchy in the transnational space

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    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-Roldån, 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

    11th German Conference on Chemoinformatics (GCC 2015) : Fulda, Germany. 8-10 November 2015.

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    Effectiveness of neonatal pulse oximetry screening for detection of critical congenital heart disease in daily clinical routine—results from a prospective multicenter study

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    Pulse oximetry screening (POS) has been proposed as an effective, noninvasive, inexpensive tool allowing earlier diagnosis of critical congenital heart disease (cCHD). Our aim was to test the hypothesis that POS can reduce the diagnostic gap in cCHD in daily clinical routine in the setting of tertiary, secondary and primary care centres. We conducted a prospective multicenter trial in Saxony, Germany. POS was performed in healthy term and post-term newborns at the age of 24–72 h. If an oxygen saturation (SpO2) of ≀95% was measured on lower extremities and confirmed after 1 h, complete clinical examination and echocardiography were performed. POS was defined as false-negative when a diagnosis of cCHD was made after POS in the participating hospitals/at our centre. From July 2006–June 2008, 42,240 newborns from 34 institutions have been included. Seventy-two children were excluded due to prenatal diagnosis (n = 54) or clinical signs of cCHD (n = 18) before POS. Seven hundred ninety-five newborns did not receive POS, mainly due to early discharge after birth (n = 727; 91%). In 41,445 newborns, POS was performed. POS was true positive in 14, false positive in 40, true negative in 41,384 and false negative in four children (three had been excluded for violation of study protocol). Sensitivity, specificity, positive and negative predictive value were 77.78%, 99.90%, 25.93% and 99.99%, respectively. With POS as an adjunct to prenatal diagnosis, physical examination and clinical observation, the percentage of newborns with late diagnosis of cCHD was 4.4%. POS can substantially reduce the postnatal diagnostic gap in cCHD, and false-positive results leading to unnecessary examinations of healthy newborns are rare. POS should be implemented in routine postnatal care
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