445 research outputs found

    Coronagraph particulate measurements. Skylab flight experiment T025

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    Major results of the Skylab T025 Coronagraph experiment designed to monitor the particulate contamination about the spacecraft and to study the earth's atmospheric aerosol distribution are presented. A model for comet outbursts based on the properties of amorphous ice and ground based narrow-band and white light photography of comet Kohoutek ten days to perihelion are included. The effect of atmospheric refraction on the analysis of the T025 atmospheric data was also investigated

    Rituximab for people with multiple sclerosis

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    Objectives: This is a protocol for a Cochrane Review (intervention). The objectives are as follows:. The main objective is to assess the benefits and harms of rituximab compared to placebo or another DMT for people with multiple sclerosis. Specific comparisons include:. rituximab compared with placebo or other DMTs as first choice treatment for relapsing forms of MS; rituximab when switching from another DMT compared with placebo or other DMTs for relapsing forms of MS; rituximab compared with placebo or other DMTs as first choice treatment for progressive forms of MS; and rituximab when switching from another DMT compared with placebo or other DMTs for progressive forms of MS

    Distance as a barrier to cancer diagnosis and treatment: Review of the literature

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    The burden of travel from a patient’s residence to health care providers is an important issue that can influence access to diagnosis and treatment ofcancer.Although several studies have shown that the travel burden can result in delays in diagnosis and treatment of many common cancers, its role appears underestimated in the treatment of patients in clinical practice. Therefore, we performed a review of the published data on the role of travel burden influencing four items: delay of diagnosis, adequate treatment of cancer, outcome, and quality of life of cancer patients. Forty-seven studies published up to December 2014 were initially identified. Twenty studies were excluded because they did not regard specifically the four items of our review.Twenty-seven studies formed the basis of our study and involved 716,153 patients. The associations between travel burden and (a) cancer stage at diagnosis (12 studies), (b) appropriate treatment (8 studies), (c) outcome (4 studies), and (d) quality of life (1 study) are reported. In addition, in two studies,therelationbetween travel burden and compliance with treatment was examined. The results of our review show that increasing travel requirements are associated with more advanced disease at diagnosis, inappropriatetreatment, aworse prognosis, and a worse quality of life. These results suggest that clinical oncologists should remember the specific travel burden problem for cancer patients, who often need health care services every week or every month for many years

    Evaluating the quality of evidence from a network meta-analysis

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    Systematic reviews that collate data about the relative effects of multiple interventions via network meta-analysis are highly informative for decision-making purposes. A network meta-analysis provides two types of findings for a specific outcome: the relative treatment effect for all pairwise comparisons, and a ranking of the treatments. It is important to consider the confidence with which these two types of results can enable clinicians, policy makers and patients to make informed decisions. We propose an approach to determining confidence in the output of a network meta-analysis. Our proposed approach is based on methodology developed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group for pairwise meta-analyses. The suggested framework for evaluating a network meta-analysis acknowledges (i) the key role of indirect comparisons (ii) the contributions of each piece of direct evidence to the network meta-analysis estimates of effect size; (iii) the importance of the transitivity assumption to the validity of network meta-analysis; and (iv) the possibility of disagreement between direct evidence and indirect evidence. We apply our proposed strategy to a systematic review comparing topical antibiotics without steroids for chronically discharging ears with underlying eardrum perforations. The proposed framework can be used to determine confidence in the results from a network meta-analysis. Judgements about evidence from a network meta-analysis can be different from those made about evidence from pairwise meta-analyses. © 2014 Salanti et al

    OSS-1/STS-3 Shuttle induced atmosphere experiment

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    Direct light form the Sun and the sunlit Earth, and indirect light from these same sources reflected off parts of the orbiter and its payload were the two major sources of light seen in the bay during spacecraft day. Brightness arising from sunlight reflected off particulates originating from the spacecraft (corona or induced atmosphere) were tentatively identified. Sources of light observed during spacecraft night include large scale diffuse glows associated with Vernier thruster firings, surface glows on the orbiter in the direction of orbiter n motion, and periodic sky brightness structures observed primarily at 4200 A and 6300 A. Some information was obtained on the size and trajectories of individual contaminant particulates. Astronomical data were obtained from large regions of the Milky Way and zodiacal light, including large regions to within 35 deg of the Sun and possibly closer. Coordinated and sometimes simultaneous observations were successfully made from Hawaii and from STS-3 to provide unique information on atmospheric sources and sinks of radiation

    Stem cell transplantation for ischemic stroke

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    Background Stroke is a leading cause of morbidity and mortality worldwide, with very large healthcare and social costs, and a strong demand for alternative therapeutic approaches. Preclinical studies have shown that stem cells transplanted into the brain can lead to functional improvement. However, to date, evidence for the benefits of stem cell transplantation in people with ischemic stroke is lacking. This is the first update of the Cochrane review published in 2010. Objectives To assess the efficacy and safety of stem cell transplantation compared with control in people with ischemic stroke. Search methods We searched the Cochrane Stroke Group Trials Register (last searched August 2018), CENTRAL (last searched August 2018), MED-LINE (1966 to August 2018), Embase (1980 to August 2018), and BIOSIS (1926 to August 2018). We handsearched potentially relevant conference proceedings, screened reference lists, and searched ongoing trials and research registers (last searched August 2018). We also contacted individuals active in the field and stem cell manufacturers (last contacted August 2018). Selection criteria We included randomized controlled trials (RCTs) that recruited people with ischemic stroke, in any phase of the disease (acute, subacute or chronic), and an ischemic lesion confirmed by computerized tomography or magnetic resonance imaging scan. We included all types of stem cell transplantation, regardless of cell source (autograft, allograft, or xenograft; embryonic, fetal, or adult; from brain or other tissues), route of cell administration (systemic or local), and dosage. The primary outcome was efficacy (assessed as neurologic impairment or functional outcome) at longer term follow-up (minimum six months). Secondary outcomes included post-procedure safety outcomes (death, worsening of neurological deficit, infections, and neoplastic transformation). Data collection and analysis Two review authors independently applied the inclusion criteria, assessed trial quality and risk of bias, and extracted data. If needed, we contacted study authors for additional information. We performed random effects meta-analyses when two or more RCTs were available for any outcome. We assessed the certainty of the evidence by using the GRADE approach. Main results In this updated review, we included seven completed RCTs with 401 participants. All tested adult human non-neural stem cells; cells were transplanted during the acute, subacute, or chronic phase of ischemic stroke; administered intravenously, intra-arterially, intracerebrally, or into the lumbar subarachnoid space. Follow-up ranged from six months to seven years. Efficacy outcomes were measured with the National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS), or Barthel Index (BI). Safety outcomes included case fatality, and were measured at the end of the trial. Overall, stem cell transplantation was associated with a better clinical outcome when measured with the NIHSS (mean difference [MD]-1.49, 95% confidence interval [CI]-2.65 to-0.33; five studies, 319 participants; low-certainty evidence), but not with the mRS (MD-0.42, 95% CI-0.86 to 0.02; six studies, 371 participants; very low-certainty evidence), or the BI (MD 14.09, 95% CI-1.94 to 30.13; three studies, 170 participants; very low-certainty evidence). The studies in favor of stem cell transplantation had, on average, a higher risk of bias, and a sample size of 32 or fewer participants. No significant safety concerns associated with stem cell transplantation were raised with respect to death (risk ratio [RR] 0.66, 95% CI 0.39 to 1.14; six studies, participants; low-certainty evidence). We were not able to perform the sensitivity analysis according to the quality of studies, because all of them were at high risk of bias. Authors’ conclusions Overall, in participants with ischemic stroke, stem cell transplantation was associated with a reduced neurological impairment, but not with a better functional outcome. No obvious safety concerns were raised. However, these conclusions came mostly from small RCTs with high risk of bias, and the certainty of the evidence ranged from low to very low. More well-designed trials are needed

    Determining the Effects of Transcranial Direct Current Stimulation on Tinnitus, Depression, and Anxiety: A Systematic Review

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    (1) Background: Tinnitus is the awareness of a sound in the absence of an external source. It affects around 10–15% of people, a significant proportion of whom also experience symptoms such as depression or anxiety that negatively affect their quality of life. Transcranial direct current stimulation (tDCS) is a technique involving constant low-intensity direct current delivered via scalp electrodes. It is a potential treatment option for tinnitus, as well as tinnitus-related conditions such as depression and anxiety. This systematic review estimates the effects of tDCS on outcomes relevant to tinnitus. In addition, it sheds light on the relationship between stimulation parameters and the effect of tDCS on these outcomes; (2) Methods: Exhaustive searches of electronic databases were conducted. Randomised controlled trials were included if they reported at least one of the following outcomes: tinnitus symptom severity, anxiety, or depression. Where available, data on quality of life, adverse effects, and neurophysiological changes were also reviewed. GRADE was used to assess the certainty in the estimate; (3) Results: Meta-analyses revealed a statistically significant reduction in tinnitus (moderate certainty) and depression (low certainty)-but not anxiety-following active tDCS compared to sham control. Network meta-analyses revealed potential optimal stimulation parameters; (4) Conclusions: The evidence synthesised in this review suggests tDCS has the potential to reduce symptom severity in tinnitus and depression. It further narrows down the number of potentially optimal stimulation parameters

    Comparative efficacy and tolerability of first-generation and newer-generation antidepressant medications for depressive disorders in children and adolescents: Study protocol for a systematic review and network meta-analysis

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    Introduction: Depressive disorders are among the most common psychiatric disorders in children and adolescents, and have adverse effects on their psychosocial functioning. Questions concerning the efficacy and safety of antidepressant medications in the treatment of depression in children and adolescents, led us to integrate the direct and indirect evidence using network meta-analysis to create hierarchies of these drugs. Methods and analysis: Seven databases with PubMed, EMBASE, the Cochrane Library, Web of Science, CINAHL, LiLACS and PsycINFO will be searched from 1966 to December 2013 (updated to May, 2015). There are no restrictions on language or type of publication. Randomised clinical trials assessing first-generation and newer-generation antidepressant medications against active comparator or placebo as acute treatment for depressive disorders in children and adolescents (under 18 years of age) will be included. The primary outcome for efficacy will be mean improvement in depressive symptoms, as measured by the mean change score of a depression rating scale from baseline to post-treatment. The tolerability of treatment will be defined as side effect discontinuation, as defined by the proportion of patients who discontinued treatment due to adverse events during the trial. We will also assess the secondary outcome for efficacy (response rate), acceptability (all-cause discontinuation) and suiciderelated outcomes. We will perform the Bayesian network meta-analyses for all relative outcome measures. Subgroup analyses and sensitivity analyses will be conducted to assess the robustness of the findings. Dissemination: The network meta-analysis will provide useful information on antidepressant treatment for child and adolescent depression. The results will be disseminated through peer-reviewed publication or conference presentations

    Development and validation of a life expectancy estimator for multimorbid older adults: A cohort study protocol

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    Background Older multimorbid adults have a high risk of mortality and a short life expectancy (LE). Providing high-value care and avoiding care overuse, including of preventive care, is a serious challenge among multimorbid patients. While guidelines recommend to tailor preventive care according to the estimated LE, there is no tool to estimate LE in this specific population. Our objective is therefore to develop an LE estimator for older multimorbid adults by transforming a mortality prognostic index, which will be developed and internally validated in a prospective cohort. Methods and analysis We will analyse data of the Optimising Therapy to Prevent Avoidable Hospital Admissions in Multimorbid Older People cohort study in Bern, Switzerland. 822 participants were included at hospitalisation with age of 70 years or older, multimorbidity (three or more chronic medical conditions) and polypharmacy (use of five drugs or more for >30 days). All-cause mortality will be assessed during 3 years of follow-up. We will apply a flexible parametric survival model with backward stepwise selection to identify the mortality risk predictors. The model will be internally validated using bootstrapping techniques. We will derive a point-based risk score from the regression coefficients. We will transform the 3-year mortality prognostic index into an LE estimator using the Gompertz survival function. We will perform a qualitative assessment of the clinical usability of the LE estimator and its application. We will conduct the development and validation of the mortality prognostic index following the Prognosis Research Strategy (PROGRESS) framework and report it following the Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis (TRIPOD) statement. Ethics and dissemination Written informed consent by patients themselves or, in the case of cognitive impairment, by a legal representative, was required before enrolment. The local ethics committee (Kantonale Ethikkommission Bern) has approved the study. We plan to publish the results in peer-reviewed journals and present them at national and international conferences

    Screening and treatment of hypertension in older adults: Less is more?

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    Screening and treatment of hypertension is a cornerstone of cardiovascular disease (CVD) prevention. Hypertension causes a large proportion of cases of stroke, coronary heart disease, heart failure, and associated disability and is highly prevalent especially among older adults. On the one hand, there is robust evidence that screening and treatment of hypertension prevents CVD and decreases mortality in the middle-aged population. On the other hand, among older adults, observational studies have shown either positive, negative, or no correlation between blood pressure (BP) and cardiovascular outcomes. Furthermore, there is a lack of high quality evidence for a favorable harm-benefit balance of antihypertensive treatment among older adults, especially among the oldest-old (i.e., above the age of 80 years), because very few trials have been conducted in this population. The optimal target BP may be higher among older treated hypertensive patients than among middle-aged. In addition, among frail or multimorbid older individuals, a relatively low BP may be associated with worse outcomes, and antihypertensive treatment may cause more harm than benefit. To guide hypertension screening and treatment recommendations among older patients, additional studies are needed to determine the most efficient screening strategies, to evaluate the effect of lowering BP on CVD risk and on mortality, to determine the optimal target BP, and to better understand the relationship between BP, frailty, multimorbidity, and health outcomes
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