1,756 research outputs found

    DNA replication: archaeal oriGINS

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    GINS is an essential eukaryotic DNA replication factor that is found in a simplified form in Archaea. A new study in this issue of BMC Biology reveals the first structure of the archaeal GINS complex. The structure reveals the anticipated similarity to the previously determined eukaryotic complex but also has some intriguing differences in the relative disposition of subunit domains

    Observation of the nonlinear Hall effect under time reversal symmetric conditions

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    The electrical Hall effect is the production of a transverse voltage under an out-of-plane magnetic field. Historically, studies of the Hall effect have led to major breakthroughs including the discoveries of Berry curvature and the topological Chern invariants. In magnets, the internal magnetization allows Hall conductivity in the absence of external magnetic field. This anomalous Hall effect (AHE) has become an important tool to study quantum magnets. In nonmagnetic materials without external magnetic fields, the electrical Hall effect is rarely explored because of the constraint by time-reversal symmetry. However, strictly speaking, only the Hall effect in the linear response regime, i.e., the Hall voltage linearly proportional to the external electric field, identically vanishes due to time-reversal symmetry. The Hall effect in the nonlinear response regime, on the other hand, may not be subject to such symmetry constraints. Here, we report the observation of the nonlinear Hall effect (NLHE) in the electrical transport of the nonmagnetic 2D quantum material, bilayer WTe2. Specifically, flowing an electrical current in bilayer WTe2 leads to a nonlinear Hall voltage in the absence of magnetic field. The NLHE exhibits unusual properties sharply distinct from the AHE in metals: The NLHE shows a quadratic I-V characteristic; It strongly dominates the nonlinear longitudinal response, leading to a Hall angle of about 90 degree. We further show that the NLHE directly measures the "dipole moment" of the Berry curvature, which arises from layer-polarized Dirac fermions in bilayer WTe2. Our results demonstrate a new Hall effect and provide a powerful methodology to detect Berry curvature in a wide range of nonmagnetic quantum materials in an energy-resolved way

    Does anxiety moderate the effectiveness of mirtazapine in patients with treatment-resistant depression? A secondary analysis of the MIR trial

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    BACKGROUND: There is a lack of evidence to guide treatment of comorbid depression and anxiety. Preliminary evidence suggests mirtazapine may be effective in treating patients with both depression and anxiety symptoms. METHODS: We undertook a secondary analysis of mirtazapine (MIR): a placebo-controlled trial of the addition of mirtazapine to a selective serotonin reuptake inhibitor or serotonin-norepinephrine reuptake inhibitor in treatment-resistant depression (TRD) in primary care. We subdivided participants into three groups by baseline generalized anxiety disorder score (GAD-7): severe (GAD-7 ⩾ 16), moderate (GAD-7 = 11-15), no/mild (GAD-7 ⩽ 10). We used linear regression including likelihood-ratio testing of interaction terms to assess how baseline anxiety altered the response of participants to mirtazapine as measured by 12-week GAD-7 and Beck Depression Inventory II (BDI-II) scores. RESULTS: Baseline generalized anxiety moderated mirtazapine's effect as measured by GAD-7 (p = 0.041) and BDI-II (p = 0.088) at 12 weeks. Participants with severe generalized anxiety receiving mirtazapine had lower 12-week GAD-7 score (adjusted difference between means (ADM) -2.82, 95% confidence interval (CI) -0.69 to -4.95) and larger decreases in BDI-II score (ADM -6.36, 95% CI -1.60 to -10.84) than placebo. Conversely, there was no anxiolytic benefit (ADM 0.28, 95% CI -1.05 to 1.60) or antidepressant benefit (ADM -0.17, 95% CI -3.02 to 2.68) compared with placebo in those with no/mild generalized anxiety. CONCLUSIONS: These findings extend the evidence for the effectiveness of mirtazapine to reduce generalized anxiety in TRD in primary care. These results may inform targeted prescribing in depression based on concurrent anxiety symptoms, although these conclusions are constrained by the post-hoc nature of this analysis

    Can changing the timing of outdoor air intake reduce indoor concentrations of traffic-related pollutants in schools?

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    Traffic emissions have been associated with a wide range of adverse health effects. Many schools are situated close to major roads, and as children spend much of their day in school, methods to reduce traffic‐related air pollutant concentrations in the school environment are warranted. One promising method to reduce pollutant concentrations in schools is to alter the timing of the ventilation so that high ventilation time periods do not correspond to rush hour traffic. Health Canada, in collaboration with the Ottawa‐Carleton District School Board, tested the effect of this action by collecting traffic‐related air pollution data from four schools in Ottawa, Canada, during October and November 2013. A baseline and intervention period was assessed in each school. There were statistically significant (P < 0.05) reductions in concentrations of most of the pollutants measured at the two late‐start (9 AM start) schools, after adjusting for outdoor concentrations and the absolute indoor–outdoor temperature difference. The intervention at the early‐start (8 AM start) schools did not have significant reductions in pollutant concentrations. Based on these findings, changing the timing of the ventilation may be a cost‐effective mechanism of reducing traffic‐related pollutants in late‐start schools located near major roads

    Standard wide local excision or bilateral reduction mammoplasty in large-breasted women with small tumours: Surgical and patient-reported outcomes.

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    Introduction Oncoplastic breast surgery is used to extend the role of breast-conserving surgery (BCS) to women with an unfavourable tumour to breast volume ratio. However, large-breasted women with a relatively small breast cancer may be offered bilateral reduction mammoplasty (BRM) despite being suitable for standard BCS as the more complex surgery may have advantages in terms of patient satisfaction and reduced adverse effects of radiotherapy.Patient and methods This retrospective study evaluated surgical and patient-reported outcome measures (PROMs) in large-breasted women with early ( 0.05).Conclusion Limitations of this study mean it can only be regarded as hypothesis-generating. Nonetheless, the trends merit a prospective study to investigate the optimal management of smaller breast cancers in larger-breasted women

    Bilateral mammoplasty for cancer: Surgical, oncological and patient-reported outcomes.

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    Introduction Bilateral mammoplasty (BM) can optimise oncological safety and aesthetic outcomes in women with large or ptotic breasts whose tumour to breast volume ratio or tumour location pose a challenge to standard breast-conserving therapy (BCT) and for whom mastectomy (with or without reconstruction) may be the only alternative.Methods We undertook a comprehensive analysis of surgical outcomes (complications according to the Clavien Dindo classification), acute radiation morbidity (Radiation Therapy Oncology Group classification), oncological outcomes, and patient satisfaction (BREAST-Q questionnaire) in women who underwent BM for breast cancer (BC) from June 2009-November 2014.Results 168 women were included. Median age was 55 years (range:33-84) and median tumour size at imaging 35 mm (range:0-170). Median specimen weight was 242 g (range 39-1824). The wise pattern technique was used in 87.5% of procedures. At least one complication occurred in 68 (40.5%) women, mostly Clavien Dindo grade 1. Grade 3 complications were infrequent (8.9%) but occurred mainly on the therapeutic mammoplasty (TM) side (p < 0.05). Complications were associated with higher BMI, specimen weight and longer time to radiotherapy (p < 0.05). Median follow-up was 37 months (range: 13-77). Local recurrence occurred in 3 (1.8%), distant metastases in 5 (3.0%), and 10 (6.0%) women have died. The median score for 'satisfaction with breasts' was 77 (range: 0-100).Conclusions This study provides concurrent data on surgical, oncological and patient-reported outcomes. It offers evidence that BM is an effective treatment for breast cancer in large- or ptotic-breasted women

    Primary radiotherapy and deep inferior epigastric perforator flap reconstruction for patients with breast cancer (PRADA): a multicentre, prospective, non-randomised, feasibility study

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    BACKGROUND: Radiotherapy before mastectomy and autologous free-flap breast reconstruction can avoid adverse radiation effects on healthy donor tissues and delays to adjuvant radiotherapy. However, evidence for this treatment sequence is sparse. We aimed to explore the feasibility of preoperative radiotherapy followed by skin-sparing mastectomy and deep inferior epigastric perforator (DIEP) flap reconstruction in patients with breast cancer requiring mastectomy. METHODS: We conducted a prospective, non-randomised, feasibility study at two National Health Service trusts in the UK. Eligible patients were women aged older than 18 years with a laboratory diagnosis of primary breast cancer requiring mastectomy and post-mastectomy radiotherapy, who were suitable for DIEP flap reconstruction. Preoperative radiotherapy started 3-4 weeks after neoadjuvant chemotherapy and was delivered to the breast, plus regional nodes as required, at 40 Gy in 15 fractions (over 3 weeks) or 42·72 Gy in 16 fractions (over 3·2 weeks). Adverse skin radiation toxicity was assessed preoperatively using the Radiation Therapy Oncology Group toxicity grading system. Skin-sparing mastectomy and DIEP flap reconstruction were planned for 2-6 weeks after completion of preoperative radiotherapy. The primary endpoint was the proportion of open breast wounds greater than 1 cm width requiring a dressing at 4 weeks after surgery, assessed in all participants. This study is registered with ClinicalTrials.gov, NCT02771938, and is closed to recruitment. FINDINGS: Between Jan 25, 2016, and Dec 11, 2017, 33 patients were enrolled. At 4 weeks after surgery, four (12·1%, 95% CI 3·4-28·2) of 33 patients had an open breast wound greater than 1 cm. One (3%) patient had confluent moist desquamation (grade 3). There were no serious treatment-related adverse events and no treatment-related deaths. INTERPRETATION: Preoperative radiotherapy followed by skin-sparing mastectomy and immediate DIEP flap reconstruction is feasible and technically safe, with rates of breast open wounds similar to those reported with post-mastectomy radiotherapy. A randomised trial comparing preoperative radiotherapy with post-mastectomy radiotherapy is required to precisely determine and compare surgical, oncological, and breast reconstruction outcomes, including quality of life. FUNDING: Cancer Research UK, National Institute for Health Research

    Fish introductions and light modulate food web fluxes in tropical streams: a whole-ecosystem experimental approach

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    Decades of ecological study have demonstrated the importance of top-down and bottom-up controls on food webs, yet few studies within this context have quantified the magnitude of energy and material fluxes at the whole-ecosystem scale. We examined top-down and bottom-up effects on food web fluxes using a field experiment that manipulated the presence of a consumer, the Trinidadian guppy Poecilia reticulata, and the production of basal resources by thinning the riparian forest canopy to increase incident light. To gauge the effects of these reach-scale manipulations on food web fluxes, we used a nitrogen (N-15) stable isotope tracer to compare basal resource treatments (thinned canopy vs. control) and consumer treatments (guppy introduction vs. control). The thinned canopy stream had higher primary production than the natural canopy control, leading to increased N fluxes to invertebrates that feed on benthic biofilms (grazers), fine benthic organic matter (collector-gatherers), and organic particles suspended in the water column (filter feeders). Stream reaches with guppies also had higher primary productivity and higher N fluxes to grazers and filter feeders. In contrast, N fluxes to collector-gatherers were reduced in guppy introduction reaches relative to upstream controls. N fluxes to leaf-shredding invertebrates, predatory invertebrates, and the other fish species present (Hart\u27s killifish, Anablepsoides hartii) did not differ across light or guppy treatments, suggesting that effects on detritus-based linkages and upper trophic levels were not as strong. Effect sizes of guppy and canopy treatments on N flux rates were similar for most taxa, though guppy effects were the strongest for filter feeding invertebrates while canopy effects were the strongest for collector-gatherer invertebrates. Combined, these results extend previous knowledge about top-down and bottom-up controls on ecosystems by providing experimental, reach-scale evidence that both pathways can act simultaneously and have equally strong influence on nutrient fluxes from inorganic pools through primary consumers

    Differential expression of collectins in human placenta and role in inflammation during spontaneous Labor.

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    © 2014 Yadav et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Collectins, collagen-containing Ca2+ dependent C-type lectins and a class of secretory proteins including SP-A, SP-D and MBL, are integral to immunomodulation and innate immune defense. In the present study, we aimed to investigate their placental transcript synthesis, labor associated differential expression and localization at feto-maternal interface, and their functional implication in spontaneous labor. The study involved using feto-maternal interface (placental/decidual tissues) from two groups of healthy pregnant women at term (≥37 weeks of gestation), undergoing either elective C-section with no labor ('NLc' group, n = 5), or normal vaginal delivery with spontaneous labor ('SLv' group, n = 5). The immune function of SP-D, on term placental explants, was analyzed for cytokine profile using multiplexed cytokine array. SP-A, SP-D and MBL transcripts were observed in the term placenta. The 'SLv' group showed significant up-regulation of SP-D (p = 0.001), and down-regulation of SP-A (p = 0.005), transcripts and protein compared to the 'NLc' group. Significant increase in 43 kDa and 50 kDa SP-D forms in placental and decidual tissues was associated with the spontaneous labor (p<0.05). In addition, the MMP-9-cleaved form of SP-D (25 kDa) was significantly higher in the placentae of 'SLv' group compared to the 'NLc' group (p = 0.002). Labor associated cytokines IL-1α, IL-1β, IL-6, IL-8, IL-10, TNF-α and MCP-1 showed significant increase (p<0.05) in a dose dependent manner in the placental explants treated with nSP-D and rhSP-D. In conclusion, the study emphasizes that SP-A and SP-D proteins associate with the spontaneous labor and SP-D plausibly contributes to the pro-inflammatory immune milieu of feto-maternal tissues.Funding provided by BT/PR15227/BRB/10/906/2011) Department of Biotechnology (DBT), Government of India http://dbtindia.nic.in/index.asp (TM) and Indian Council of Medical Research (ICMR) Junior Research Fellowship (JRF)/Senior Research Fellowship (SRF), Government of India, www.icmr.nic.in (AKY)

    Clinical management and research priorities for high-risk prostate cancer in the UK:meeting report of a multidisciplinary panel in conjunction with the NCRI Prostate Cancer Clinical Studies Localised Subgroup

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    The management of high-risk prostate cancer has become increasingly sophisticated, with refinements in radical therapy and the inclusion of adjuvant local and systemic therapies. Despite this, high-risk prostate cancer continues to have significant treatment failure rates, with progression to metastasis, castrate resistance and ultimately disease-specific death. In an effort to discuss the challenges in this field, the UK National Clinical Research Institute’s Prostate Cancer Clinical Studies localised subgroup convened a multidisciplinary national meeting in the autumn of 2014. The remit of the meeting was to debate and reach a consensus on the key clinical and research challenges in high-risk prostate cancer and to identify themes that the UK would be best placed to pursue to help improve outcomes. This report presents the outcome of those discussions and the key recommendations for future research in this highly heterogeneous disease entity
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