453 research outputs found
Can we predict non-response in developmental tasks? Assessing the longitudinal relation between toddlers’ non-response and early academic skills
Can we predict non-response in developmental tasks? Assessing the longitudinal relation between toddlers’ non-response and early academic skills
Search for Rayleigh scattering in the atmosphere of GJ1214b
We investigate the atmosphere of GJ1214b, a transiting super-Earth planet
with a low mean density, by measuring its transit depth as a function of
wavelength in the blue optical portion of the spectrum. It is thought that this
planet is either a mini-Neptune, consisting of a rocky core with a thick,
hydrogen-rich atmosphere, or a planet with a composition dominated by water.
Most observations favor a water-dominated atmosphere with a small scale-height,
however, some observations indicate that GJ1214b could have an extended
atmosphere with a cloud layer muting the molecular features. In an atmosphere
with a large scale-height, Rayleigh scattering at blue wavelengths is likely to
cause a measurable increase in the apparent size of the planet towards the
blue. We observed the transit of GJ1214b in the B-band with the FOcal Reducing
Spectrograph (FORS) at the Very Large Telescope (VLT) and in the g-band with
both ACAM on the William Hershel Telescope (WHT) and the Wide Field Camera
(WFC) at the Isaac Newton Telescope (INT). We find a planet-to-star radius
ratio in the B-band of 0.1162+/-0.0017, and in the g-band 0.1180+/-0.0009 and
0.1174+/-0.0017 for the WHT & INT observations respectively. These optical data
do not show significant deviations from previous measurements at longer
wavelengths. In fact, a flat transmission spectrum across all wavelengths best
describes the combined observations. When atmospheric models are considered a
small scale-height water-dominated model fits the data best.Comment: Accepted for publication in Ap
Primary retroperitoneal soft tissue sarcoma: Imaging appearances, pitfalls and diagnostic algorithm.
Although retroperitoneal sarcomas are rare tumours, they can be encountered by a wide variety of clinicians as they can be incidental findings on imaging or present with non specific symptoms and signs. Surgical resection can offer hope of cure and patient outcomes are improved when patients are managed in high-volume specialist centers. Failure to recognize retroperitoneal sarcomas on imaging can lead to inappropriate management in inexperienced centers. Therefore it is critical that a diagnosis of retroperitoneal sarcoma should be considered in the differential diagnosis of a retroperitoneal mass with prompt referral to a soft tissue sarcoma unit. In particular, the most common retroperitoneal sarcoma subtypes, liposarcoma and leiomyosarcoma, have characteristic imaging appearances which are discussed. This review therefore aims to set the context and guide clinicians through a diagnostic pathway for retroperitoneal masses in adults which arise extrinsic to the solid abdominal viscera
Female Sex and IL28B, a Synergism for Spontaneous Viral Clearance in Hepatitis C Virus (HCV) Seroconverters from a Community-Based Cohort
BACKGROUND & AIMS: Since acute hepatitis C virus (HCV) infection is often asymptomatic, it is difficult to examine the rate and determinants of spontaneous clearance. Consequently, these studies are subject to bias, which can potentially lead to biased rates of viral clearance and risk estimates. We evaluated determinants of spontaneous HCV clearance among HCV seroconverters identified in a unique community-based cohort. METHODS: Subjects were 106 drug users with documented dates of HCV seroconversion from the Amsterdam Cohort Study. Logistic regression was used to examine sociodemographic, behavioral, clinical, viral and host determinants, measured around acute infection, of HCV clearance. RESULTS: The spontaneous viral clearance rate was 33.0% (95% confidence interval (CI) 24.2-42.8). In univariate analyses female sex and fever were significantly associated with spontaneous clearance. The favorable genotypes for rs12979860 (CC) and rs8099917 (TT) were associated with spontaneous clearance, although borderline significant. In multivariate analysis, females with the favorable genotype for rs12979860 (CC) had an increased odds to spontaneously clear HCV infection (adjusted OR 6.62, 95% 2.69-26.13), whereas females with the unfavorable genotype were as likely as men with the favorable and unfavorable genotype to clear HCV. Chronic Hepatitis B infection and absence of HIV coinfection around HCV seroconversion also favor HCV clearance. CONCLUSIONS: This study shows that co-infection with HIV and HBV and genetic variation in the IL28B region play an important role in spontaneous clearance of HCV. Our findings suggest a possible synergistic interaction between female sex and IL28B in spontaneous clearance of HCV
Epidemiology of acute and chronic hepatitis B virus infection in Norway, 1992-2009
<p>Abstract</p> <p>Background</p> <p>Norway is classified as a low prevalence country for hepatitis B virus infection. Vaccination is only recommended for risk groups (intravenous drug users (IDUs), Men who have Sex with Men (MSM), immigrants and contacts of known carriers). We describe the epidemiology of reported cases of hepatitis B in Norway, during the years 1992-2009 in order to assess the validity of current risk groups and recommend preventive measures.</p> <p>Methods</p> <p>We used case based data from the national surveillance system on acute and chronic hepatitis B. The Norwegian Statistics Bureau provided population and migration data and the Norwegian Institute for Alcohol and Drug Research the estimated number of active IDUs between 2002-2007. Incidence rates (IR) and incidence rate ratios (IRR) for acute hepatitis B and notification rates (NR) and notification rate ratios (NRR) for chronic hepatitis B with 95% confidence intervals were calculated.</p> <p>Results</p> <p>The annual IR of acute hepatitis B ranged from 0.7/100,000 (1992) to 10.6/100,000 (1999). Transmission occurred mainly among IDUs (64%) or through sexual contact (24%). The risk of acquiring acute hepatitis B was highest in people aged 20-29 (IRR = 6.6 [3.3-13.3]), and in males (IRR = 2.4 [1.7-3.3]). We observed two peaks of newly reported chronic hepatitis B cases in 2003 and 2009 (NR = 17.6/100,000 and 17.4/100,000, respectively). Chronic hepatitis B was more likely to be diagnosed among immigrants than among Norwegians (NRR = 93 [71.9-120.6]), and among those 20-29 compared to those 50-59 (NRR = 5.2 [3.5-7.9]).</p> <p>Conclusions</p> <p>IDUs remain the largest risk group for acute hepatitis B. The observed peaks of chronic hepatitis B are related to increased immigration from high endemic countries and screening and vaccination of these groups is important to prevent further spread of infection. Universal screening of pregnant women should be introduced. A universal vaccination strategy should be considered, given the high cost of reaching the target populations. We recommend evaluating the surveillance system for hepatitis B as well as the effectiveness of screening and vaccinating immigrant populations.</p
Incidence of unplanned excisions of soft tissue sarcomas in the Netherlands:A population-based study
Introduction: Timely recognition of soft tissue sarcomas (STS) remains challenging, potentially leading to unplanned excisions (also known as 'whoops procedures'). This population-based study charted the occurrence of unplanned excisions and identified associated patient, tumour, and treatment-related characteristics. Furthermore, it presents an overview of the outcomes and clinical management following an unplanned excision. Methods: From the Netherlands Cancer Registry (NCR) database, information was obtained on 2187 adult patients diagnosed with STS in 2016-2019 who underwent surgery. Tumours located in the mediastinum, heart or retroperitoneum were excluded, as well as incidental findings. Differences between patients with planned and unplanned excisions were assessed with chi-square tests and a multivariable logistic regression model. Results: Overall, unplanned excisions comprise 18.2% of all first operations for STS, with a quarter of them occurring outside a hospital. Within hospitals, the unplanned excision rate was 14.4%. Unplanned excisions were more often performed on younger patients, and tumours unsuspected of being STS prior to surgery were generally smaller ( Discussion: Potential improvement in preventing unplanned excisions may be achieved by better compliance to preoperative imaging and referral guidelines, and stimulating continuous awareness of STS among general surgeons, general practitioners and private practices. (C) 2021 Elsevier Ltd, BASO similar to The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved
PropAngio study protocol: a neoadjuvant trial on the efficacy of propranolol monotherapy in cutaneous angiosarcoma-a proof of principle study
INTRODUCTION: Angiosarcoma is a rare and aggressive malignancy with a high metastatic potential and recurrence rate. Despite optimal treatment with surgery, with or without radiation, the prognosis remains poor and, therefore, new treatment strategies are warranted. Recently, propranolol has effectively been repurposed for the treatment of infantile haemangioma. Propranolol is a β3-sparing antagonist of the β-adrenergic receptor. In infantile haemangioma, the β1, β2 and β3 receptors are highly expressed. Angiosarcoma has several similarities with haemangioma, including its high β-adrenergic receptor expression and the supposedly important role of vascular endothelial growth factor in malignant growth. As a result, propranolol has been administered small scale in individual angiosarcoma cases with promising results. The precise effect of propranolol, however, is not yet established. METHODS AND ANALYSIS: The goal of this neoadjuvant window of opportunity study is to prospectively evaluate the activity of propranolol monotherapy in patients with cutaneous angiosarcoma. The neoadjuvant setting provides a good opportunity to rapidly evaluate both the clinical response and histological response, without a significant delay in standard anticancer treatment. Fourteen patients with primary, recurrent or metastatic cutaneous angiosarcoma will be included. Propranolol will be administered orally in an escalating dose during 3-6 weeks, before the initiation of standard treatment. The primary endpoint is clinical response according to Response Evaluation Criteria in Solid Tumours, as measured on consecutive coloured photographs or CT/MRI. The histological response will be determined as secondary endpoint, comparing the difference in proliferation index before and after propranolol by measuring the change in immunohistochemistry staining of Ki-67. The study will be considered positive when at least three patients have a response to propranolol. ETHICS AND DISSEMINATION: Ethical approval was obtained from the Medical Ethical Committee of the Netherlands Cancer Institute. Independent of the outcome, results of this study will be shared and submitted for publication in an international peer-reviewed journal. TRIAL REGISTRATION NUMBER: NL8118; registry through the Netherlands Trial Register
Self-Organization, Layered Structure, and Aggregation Enhance Persistence of a Synthetic Biofilm Consortium
Microbial consortia constitute a majority of the earth’s biomass, but little is known about how these cooperating
communities persist despite competition among community members. Theory suggests that non-random spatial structures
contribute to the persistence of mixed communities; when particular structures form, they may provide associated
community members with a growth advantage over unassociated members. If true, this has implications for the rise and
persistence of multi-cellular organisms. However, this theory is difficult to study because we rarely observe initial instances
of non-random physical structure in natural populations. Using two engineered strains of Escherichia coli that constitute a
synthetic symbiotic microbial consortium, we fortuitously observed such spatial self-organization. This consortium forms a
biofilm and, after several days, adopts a defined layered structure that is associated with two unexpected, measurable
growth advantages. First, the consortium cannot successfully colonize a new, downstream environment until it selforganizes
in the initial environment; in other words, the structure enhances the ability of the consortium to survive
environmental disruptions. Second, when the layered structure forms in downstream environments the consortium
accumulates significantly more biomass than it did in the initial environment; in other words, the structure enhances the
global productivity of the consortium. We also observed that the layered structure only assembles in downstream
environments that are colonized by aggregates from a previous, structured community. These results demonstrate roles for
self-organization and aggregation in persistence of multi-cellular communities, and also illustrate a role for the techniques
of synthetic biology in elucidating fundamental biological principles
Widespread hepatitis B virus genotype G (HBV-G) infection during the early years of the HIV epidemic in the Netherlands among men who have sex with men
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