3,829 research outputs found

    Observation of dissipative chlorophyll-to-carotenoid energy transfer in light-harvesting complex II in membrane nanodiscs

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    Abstract Plants prevent photodamage under high light by dissipating excess energy as heat. Conformational changes of the photosynthetic antenna complexes activate dissipation by leveraging the sensitivity of the photophysics to the protein structure. The mechanisms of dissipation remain debated, largely due to two challenges. First, because of the ultrafast timescales and large energy gaps involved, measurements lacked the temporal or spectral requirements. Second, experiments have been performed in detergent, which can induce non-native conformations, or in vivo, where contributions from homologous antenna complexes cannot be disentangled. Here, we overcome both challenges by applying ultrabroadband two-dimensional electronic spectroscopy to the principal antenna complex, LHCII, in a near-native membrane. Our data provide evidence that the membrane enhances two dissipative pathways, one of which is a previously uncharacterized chlorophyll-to-carotenoid energy transfer. Our results highlight the sensitivity of the photophysics to local environment, which may control the balance between light harvesting and dissipation in vivo

    Mycotic aneurysm of the inferior gluteal artery caused by non-typhi Salmonella in a man infected with HIV: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Non-typhi <it>Salmonellae </it>infections represent major opportunistic pathogens affecting human immunodeficiency virus-infected individuals residing in sub-Saharan Africa. To the best of our knowledge, we report the first documented case in the medical literature of a <it>Salmonella</it>-induced mycotic aneurysm involving an artery supplying the gluteal region.</p> <p>Case presentation</p> <p>A 37-year-old black, Kenyan man, infected with human immunodeficiency virus with a CD4 count of 132 cells per microliter presented with a pulsatile gluteal mass and debilitating pain progressing over one week. He was receiving prophylaxis with trimethoprim-sulfamethoxazole. Aspiration of the mass yielded gross blood. An ultrasound examination revealed a 37 ml vascular structure with an intra-luminal clot. Upon exploration, a true aneurysm of the inferior gluteal artery was identified and successfully resected. A culture of the aspirate grew a non-typhi <it>Salmonellae </it>species. Following resection, he was treated with oral ciprofloxacin for 10 weeks. He later began anti-retroviral therapy. Forty-two months after the initial diagnosis, he remained alive and well.</p> <p>Conclusions</p> <p>Clinicians caring for patients infected with human immunodeficiency virus in Africa and other resource-limited settings should be aware of the invasive nature of <it>Salmonella </it>infections and the potential for aneurysm formation in unlikely anatomical locations. Rapid initiation of appropriate anti-microbial chemotherapy and surgical referral is needed. Use of trimethoprim-sulfamethoxazole prophylaxis does not routinely prevent invasive <it>Salmonella </it>infections.</p

    Radiographic assessment of the skeletons of Dolly and other clones finds no abnormal osteoarthritis

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    Our recent report detailing the health status of cloned sheep concluded that the animals had aged normally. This is in stark contrast to reports on Dolly (first animal cloned from adult cells) whose diagnoses of osteoarthritis (OA) at 5½ years of age led to considerable scientific concern and media debate over the possibility of early-onset age-related diseases in cloned animals. Our study included four 8-year old ewes derived from the cell line that gave rise to Dolly, yet none of our aged sheep showed clinical signs of OA, and they had radiographic evidence of only mild or, in one case, moderate OA. Given that the only formal record of OA in Dolly is a brief mention of a single joint in a conference abstract, this led us to question whether the original concerns about Dolly’s OA were justified. As none of the original clinical or radiographic records were preserved, we undertook radiographic examination of the skeletons of Dolly and her contemporary clones. We report a prevalence and distribution of radiographic-OA similar to that observed in naturally conceived sheep, and our healthy aged cloned sheep. We conclude that the original concerns that cloning had caused early-onset OA in Dolly were unfounded

    Probiotics to prevent infantile colic

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    Background Infantile colic is typically defined as full‐force crying for at least three hours per day, on at least three days per week, for at least three weeks. Infantile colic affects a large number of infants and their families worldwide. Its symptoms are broad and general, and while not indicative of disease, may represent a serious underlying condition in a small percentage of infants who may need a medical assessment. Probiotics are live microorganisms that alter the microflora of the host and provide beneficial health effects. The most common probiotics used are of Lactobacillus, Bifidobacterium and Streptococcus. There is growing evidence to suggest that intestinal flora in colicky infants differ from those in healthy infants, and it is suggested that probiotics can redress this balance and provide a healthier intestinal microbiota landscape. The low cost and easy availability of probiotics makes them a potential prophylactic solution to reduce the incidence and prevalence of infantile colic. Objectives To evaluate the efficacy and safety of prophylactic probiotics in preventing or reducing severity of infantile colic. Search methods In January 2018 we searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, 10 other databases and two trials registers. In addition, we handsearched the abstracts of relevant meetings, searched reference lists, ran citation searches of included studies, and contacted authors and experts in the field, including the manufacturers of probiotics, to identify unpublished trials. Selection criteria Randomised control trials (RCTs) of newborn infants less than one month of age without the diagnosis of infantile colic at recruitment. We included any probiotic, alone or in combination with a prebiotic (also known as synbiotics), versus no intervention, another intervention(s) or placebo, where the focus of the study was the effect of the intervention on infantile colic. Data collection and analysis We used standard methodological procedures of Cochrane. Main results Our search yielded 3284 records, and of these, we selected 21 reports for full‐text review. Six studies with 1886 participants met our inclusion criteria, comparing probiotics with placebo. Two studies examined Lactobacillus reuteri DSM, two examined multi‐strain probiotics, one examined Lactobacillus rhamnosus, and one examined Lactobacillus paracasei and Bifidobacterium animalis. Two studies began probiotics during pregnancy and continued administering them to the baby after birth. We considered the risk of bias for randomisation as low for all six trials; for allocation concealment as low in two studies and unclear in four others. All studies were blinded, and at low risk of attrition and reporting bias. A random‐effects meta‐analysis of three studies (1148 participants) found no difference between the groups in relation to occurrence of new cases of colic: risk ratio (RR) 0.46, 95% confidence interval (CI) 0.18 to 1.19; low‐certainty evidence; I2 = 72%. A random‐effects meta‐analysis of all six studies (1851 participants) found no difference between the groups in relation to serious adverse effects (RR 1.02, 95% CI 0.14 to 7.21; low‐certainty evidence; I2 not calculable (only four serious events for one comparison, two in each group: meconium plug obstruction, patent ductus arteriosus and neonatal hepatitis). A random‐effects meta‐analysis of three studies (707 participants) found a mean difference (MD) of –32.57 minutes per day (95% CI –55.60 to –9.54; low‐certainty evidence; I2 = 93%) in crying time at study end in favour of probiotics. A subgroup analysis of the most studied agent, Lactobacillus reuteri, showed a reduction of 44.26 minutes in daily crying with a random‐effects model (95% CI –66.6 to –21.9; I2 = 92%), in favour of probiotics. Authors' conclusions There is no clear evidence that probiotics are more effective than placebo at preventing infantile colic; however, daily crying time appeared to reduce with probiotic use compared to placebo. There were no clear differences in adverse effects. We are limited in our ability to draw conclusions by the certainty of the evidence, which we assessed as being low across all three outcomes, meaning that we are not confident that these results would not change with the addition of further researc

    Parent training programmes for managing infantile colic

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    Background Infantile colic has an effect on both infants and their parents, who become exhausted and concerned as they attempt to comfort their child. Common approaches have focused upon physical treatments to reduce symptoms, with inconclusive evidence as to their effectiveness. An alternative approach seeks to provide training, support and psychological interventions for parents. This approach is known as parent training programmes. Programmes can include soothing techniques, advice on feeding or normalisation material in any form. The teaching format can vary including face‐to‐face courses, online learning, printed materials, home visits and remote support and counselling. Here, we aim to collate the evidence on the effectiveness of these interventions and examine their effectiveness at reducing infantile colic symptoms and parental anxiety levels, and their safety. Objectives 1. To evaluate the effectiveness and safety of parent training programmes for managing colic in infants under four months of age. 2. To identify the educational content and attributes of such published programmes. Search methods In June 2019 we searched CENTRAL, MEDLINE, Embase, 13 other databases and two trials registers. We also handsearched conference abstracts, inspected the references of included studies and contacted leaders in the field for more trials. Selection criteria Randomised controlled trials (RCTs) and quasi‐RCTs investigating the effectiveness of any form of parental training programmes, alone or in combination, versus another intervention(s) or control, on infantile colic. Data collection and analysis Two authors independently selected studies for inclusion, extracted data, and assessed the risk of bias within the included studies. We used Review Manager 5 to analyse the data. We assessed the certainty of the evidence using GRADE methodology

    Social marketing applied to HIV/AIDS prevention: the case of a five-year governmental response in Portugal

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    HIV infection has been a concerning health issue prioritised by health governmental institutions that has required the development of public health policies with an integrated social marketing intervention in an upstream dimension. A behaviour change strategy should invest in segmented communication for priority targets, in partnership with multiple stakeholders. This case explores and discusses the integrated social marketing programme developed by the Portuguese Ministry of Health to prevent HIV/AIDS in the period 2006–2011 and its long-term evaluation in behaviour change, comparing data from 2005 and 2017. This case shows the initial diagnosis; the social marketing strategy developed for different targets in partnership with civil society organisations, following a variety of theoretical frameworks; and effectiveness evaluation in epidemic outcomes. A guide is provided with questions for discussion.FCT - Fundação para a Ciência e a Tecnologia(UID/SOC/04521/2013

    The Complete Star Formation History of the Universe

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    The determination of the star-formation history of the Universe is a key goal of modern cosmology, as it is crucial to our understanding of how structure in the Universe forms and evolves. A picture has built up over recent years, piece-by-piece, by observing young stars in distant galaxies at different times in the past. These studies indicated that the stellar birthrate peaked some 8 billion years ago, and then declined by a factor of around ten to its present value. Here we report on a new study which obtains the complete star formation history by analysing the fossil record of the stellar populations of 96545 nearby galaxies. Broadly, our results support those derived from high-redshift galaxies elsewhere in the Universe. We find, however, that the peak of star formation was more recent - around 5 billion years ago. Our study also shows that the bigger the stellar mass of the galaxy, the earlier the stars were formed. This striking result indicates a very different formation history for high- and low-mass formation.Comment: Accepted by Nature. Press embargo until publishe
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