261 research outputs found
Settlement and Growth of quagga mussels (Dreissenia rostriformis bugensis Andrusov, 1897) in Lake Mead, Nevada-Arizona, USA
Settlement and growth of quagga mussels Dreissena rostriformis bugensis were monitored in Lake Mead, NV, USA, where the first dreissenid occurrence was confirmed in the western United States. To measure the settlement rate of these invasive mussels, seven acrylonitrile butadiene styrene (ABS) pipes were attached to a line in shallow water (7.7 m below the surface) since November 23, 2007; eight ABS pipes were placed on another line in deep water (13.4 m below the surface) since January 3, 2008. Quagga mussels were sampled from these pipes on March 19, May 21, July 9, October 20, and December 19, 2008. Active settlement of veligers was recorded in all sampling events. The settlement rates of quagga mussels did not differ among the two lines and the highest settlement rate was found from October 20 to December 19. Three methods were used to estimate the growth of quagga mussels in Lake Mead: caged mussels, size distribution analyses on both natural populations and mussels attached to ABS pipes. Caged mussels were held in Las Vegas Boat Harbor from July 31, 2007 to March 19, 2008, where smaller mussels grew faster than larger ones. Size distribution data on two natural populations of quagga mussels collected from Sentinel Island and Indian Canyon in 2007 also showed that the growth rates decreased significantly as mussel size increased. Shell length data of cohorts collected from the ABS pipes were also used to estimate the growth of quagga mussels. The growth patterns of quagga mussels from the two lines were quite similar with the lowest growth rates detected from late summer to early autumn. The information on settlement and growth of quagga mussels from this study can help understand their population dynamics in the western United States
A standardized design for quagga mussel monitoring in Lake Mead, Nevada-Arizona
The discovery of quagga mussels (Dreissena rostriformis bugensis) in Lake Mead, Nevada-Arizona, on January 6, 2007 is the first known occurrence of dreissenid species in the western United States. This study developed elements of a cost-effective and standardized quagga mussel-monitoring program for Lake Mead using preliminary data to arrive at statistically based numbers of sampling sites. To represent the abundance of adult/juvenile quagga mussels in Lake Mead’s heterogeneous floor with 95% confidence, a stratified simple random sampling design revealed a requirement of 41 samples from hard substrates (i.e., rocky areas) and 97 samples from soft substrates (i.e., sandy and muddy areas). A simple random sampling design demonstrated that 42 samples from the lake’s water column are necessary to represent veliger abundance with 95% confidence. Other important elements of the sampling program, such as standardization of protocols and processes and suggested data analyses, are discussed. The monitoring program, which is based on reconnaissance data, is intended to be optimized with data from its first year’s samples. The sample number-selection approach and the other elements of this plan can be easily implemented by lake managers and can also be adapted to other locations where dreissenid mussel monitoring is needed
Beta blocker use in subjects with type 2 diabetes mellitus and systolic heart failure does not worsen glycaemic control
<p>Abstract</p> <p>Background</p> <p>The prognostic benefits of beta-blockers (BB) in patients with systolic heart failure (SHF) are known but despite this, in patients with diabetes they are underutilized. The aim of this study was to assess the effect of beta-blockers (BB) on glycaemic control in patients with Type 2 Diabetes (T2DM) and systolic heart failure (SHF) stratified to beta-1 selective (Bisoprolol) vs. nonselective BB (Carvedilol).</p> <p>Methods</p> <p>This observational, cohort study was conducted in patients with T2DM and SHF attending an Australian tertiary teaching hospital's heart failure services. The primary endpoint was glycaemic control measured by glycosylated haemoglobin (HbA1c) at initiation and top dose of BB. Secondary endpoints included microalbuminuria, changes in lipid profile and estimated glomerular filtration rate (eGFR).</p> <p>Results</p> <p>125 patients were assessed. Both groups were well matched for gender, NYHA class and use of guideline validated heart failure and diabetic medications. The mean treatment duration was 1.9 ± 1.1 years with carvedilol and 1.4 ± 1.0 years with bisoprolol (<it>p </it>= ns). The carvedilol group achieved a reduction in HbA1c (7.8 ± 0.21% to 7.3 ± 0.17%, <it>p </it>= 0.02) whereas the bisoprolol group showed no change in HbA1c (7.0 ± 0.20% to 6.9 ± 0.23%, <it>p </it>= 0.92). There was no significant difference in the change in HbA1c from baseline to peak BB dose in the carvedilol group compared to the bisoprolol group. There was a similar deterioration in eGFR, but no significant changes in lipid profile or microalbuminuria in both groups (<it>p </it>= ns).</p> <p>Conclusion</p> <p>BB use did not worsen glycaemic control, lipid profile or albuminuria status in subjects with SHF and T2DM. Carvedilol significantly improved glycemic control in subjects with SHF and T2DM and this improvement was non significantly better than that obtained with bisoprolol. BB's should not be withheld from patients with T2DM and SHF.</p
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Feasibility of aortic valve assessment with low dose prospectively triggered adaptive systolic (PTAS) cardiac computed tomography angiography
Background: Cardiac computed tomography angiography (CTA) is feasible for aortic valve evaluation, but retrospective gated protocols required high radiation doses for aortic valve assessment. A prospectively triggered adaptive systolic (PTAS) cardiac CT protocol was recently described in arrhythmia using second-generation dual-source CT. In this study, we sought to evaluate the feasibility of PTAS CTA to assess the aortic valve at a low radiation dose. Findings: A retrospective cohort of 29 consecutive patients whom underwent PTAS protocols for clinical indications other than aortic valve assessment and whom also received echocardiography within 2 months of CT, was identified. Images were reviewed for aortic valve morphology (tricuspid/bicuspid/prosthetic) and stenosis (AS) by experienced blinded readers. Accuracy versus echocardiography and radiation doses were assessed. All PTAS coronary CTAs were clinically diagnostic with 0 un-evaluable coronary segments. The accuracy of PTAS for aortic valve morphology was 92.6%, and for exclusion of severe AS was 93.1%. Two exams were un-evaluable for the aortic valve due to inadequate number of phases archived for interpretation. Total radiation dose was a median of 2.8 mSv (interquartile range 1.4–4.4 mSv). Conclusions: PTAS CTA protocols using second-generation dual-source CT for aortic valve evaluation are feasible at low doses. This protocol should be investigated further in larger cohorts
Can heart rate variability be a bio-index of hope? A pilot study
BackgroundHope can affect the thinking habits, emotional regulations, and behaviors of individuals. Hope is considered as a positive trait by clinicians, who often assess the level of hope in psychological evaluations. Previous measurements of hope were largely based on self-reported questionnaires leading to the problem of subjectivity. Heart Rate Variability (HRV) is a bio index that is an objective, quick, cost effective, and non-invasive measurement. HRV has been used in the evaluation of physical health and some psychiatric conditions. However, it has not been tested for its potential to be a bio-index of the level of hope.MethodThis pilot cross-sectional observational study aimed to examine the relationships between HRV and the level of hope among adult Chinese people in Hong Kong. Convenience sampling was used and 97 healthy participants were recruited. Their level of hope was measured by the Dispositional Hope Scale-Chinese (DHS-C), and their HRV was quantified by emWave Pro Plus, a reliable sensor of HRV. Spearman’s correlation coefficient analysis was performed on the HRV measurements and DHS-C.ResultsThe DHS-C’s overall mean score was 45.49. The mean scores of the subscale DHS-C (Agency) was 22.46, and the mean scores of DHS-C (Pathway) was 23.03. It was also revealed that there were significant, weak, and negative correlations between the level of hope and four out of ten HRV metrics. One HRV metric was found to have a significant, weak, and positive correlation with the level of hope.ConclusionThis study provided initial evidence to support the use of HRV as a bio-index of hope. Implications of the current study and recommendations for future research directions are discussed
Increased Coronary Atherosclerotic Plaque Vulnerability by Coronary Computed Tomography Angiography in HIV-Infected Men
a Objective: Among HIV-infected patients, high rates of MI and sudden cardiac death have been observed. Exploring potential underlying mechanisms, we used multidetector spiral coronary computed tomography angiography (coronary CTA) to compare atherosclerotic plaque morphology in HIV-infected subjects and non-HIVinfected controls. Methods: Coronary atherosclerotic plaques visualized by CTA in HIV-infected (101) and non-HIV-infected (41) men without clinically apparent heart disease matched on cardiovascular risk factors were analyzed for 3 vulnerability features: low attenuation, positive remodeling, and spotty calcification. Results: 95% of HIV-infected subjects were receiving ART (median duration 7.9 years) and had well-controlled disease (median CD4 473 cells/mm3, median HIV RNA <50 copies/ml). Age and traditional cardiovascular risk factors were similar in HIV-infected subjects and controls. Among the HIV-infected (versus control) group, there was a higher prevalence of subjects with at least one: 1) low attenuation plaque (22.8% versus 7.3%, p ¼ 0.02), 2) positively remodeled plaque (49.5% versus 31.7%, p ¼ 0.05) and 3) high-risk 3-feature plaque (7.9% versus 0%, p ¼ 0.02). Moreover, subjects in the HIVinfected (versus control) group demonstrated a higher number of low attenuation plaques (p ¼ 0.01) and positively remodeled plaques (p ¼ 0.03) per subject. Conclusions: Our data demonstrate an increased prevalence of vulnerable plaque features among relatively young HIV-infected patients. Differences in coronary atherosclerotic plaque morphology -namely, increased vulnerable plaque among HIVinfected subjects -are here for the first time reported and may contribute to increased rates of MI and sudden cardiac death in this population
The theoretical and empirical basis of a BioPsychoSocial (BPS) risk screener for detection of older people's health related needs, planning of community programs, and targeted care interventions
Background This study introduces the conceptual basis and operational measure, ofBioPyschoSocial (BPS) healthand related risk to better understand how well older people are managing and to screen for risk status. The BPS Risk Screener is constructed to detectvulnerabilityat older ages, and seeks to measure dynamic processes that place equal emphasis on Psycho-emotional and Socio-interpersonal risks, as Bio-functional ones. We validate the proposed measure and describe its application to programming. Methods We undertook a quantitative cross-sectional, psychometric study withn = 1325 older Singaporeans, aged 60 and over. We adapted the EASYCare 2010 and Lubben Social Network Scale questionnaires to help determine the BPS domains using factor analysis from which we derive the BPS Risk Screener items. We then confirm its structure, and test the scoring system. The score is initially validated against self-reported general health then modelled against: number of falls; cognitive impairment; longstanding diseases; and further tested against service utilization (linked administrative data). Results Three B, P and S clusters are defined and identified and a BPSmanaging score(‘doing’ well, or ‘some’, ‘many’, and ‘overwhelming problems’) calculated such that the risk of problematic additive BPS effects, what we term health‘loads’, are accounted for. Thirty-five items (factor loadings over 0.5) clustered into three distinct B, P, S domains and were found to be independently associated with self-reported health: B: 1.99 (1.64 to 2.41), P: 1.59 (1.28 to 1.98), S: 1.33 (1.10 to 1.60). The fit improved when combined into the managing score 2.33 (1.92 to 2.83, < 0.01). The score was associated with mounting risk for all outcomes. Conclusions BPS domain structures, and the novel scoring system capturing dynamic BPS additive effects, which can combine to engender vulnerability, are validated through this analysis. The resulting tool helps render clients’ risk status and related intervention needs transparent. Given its explicit and empirically supported attention to P and S risks, which have the potential to be more malleable than B ones, especially in the older old, this tool is designed to be change sensitive
Estimating excess 1-year mortality associated with the COVID-19 pandemic according to underlying conditions and age: a population-based cohort study.
BACKGROUND: The medical, societal, and economic impact of the coronavirus disease 2019 (COVID-19) pandemic has unknown effects on overall population mortality. Previous models of population mortality are based on death over days among infected people, nearly all of whom thus far have underlying conditions. Models have not incorporated information on high-risk conditions or their longer-term baseline (pre-COVID-19) mortality. We estimated the excess number of deaths over 1 year under different COVID-19 incidence scenarios based on varying levels of transmission suppression and differing mortality impacts based on different relative risks for the disease. METHODS: In this population-based cohort study, we used linked primary and secondary care electronic health records from England (Health Data Research UK-CALIBER). We report prevalence of underlying conditions defined by Public Health England guidelines (from March 16, 2020) in individuals aged 30 years or older registered with a practice between 1997 and 2017, using validated, openly available phenotypes for each condition. We estimated 1-year mortality in each condition, developing simple models (and a tool for calculation) of excess COVID-19-related deaths, assuming relative impact (as relative risks [RRs]) of the COVID-19 pandemic (compared with background mortality) of 1·5, 2·0, and 3·0 at differing infection rate scenarios, including full suppression (0·001%), partial suppression (1%), mitigation (10%), and do nothing (80%). We also developed an online, public, prototype risk calculator for excess death estimation. FINDINGS: We included 3 862 012 individuals (1 957 935 [50·7%] women and 1 904 077 [49·3%] men). We estimated that more than 20% of the study population are in the high-risk category, of whom 13·7% were older than 70 years and 6·3% were aged 70 years or younger with at least one underlying condition. 1-year mortality in the high-risk population was estimated to be 4·46% (95% CI 4·41-4·51). Age and underlying conditions combined to influence background risk, varying markedly across conditions. In a full suppression scenario in the UK population, we estimated that there would be two excess deaths (vs baseline deaths) with an RR of 1·5, four with an RR of 2·0, and seven with an RR of 3·0. In a mitigation scenario, we estimated 18 374 excess deaths with an RR of 1·5, 36 749 with an RR of 2·0, and 73 498 with an RR of 3·0. In a do nothing scenario, we estimated 146 996 excess deaths with an RR of 1·5, 293 991 with an RR of 2·0, and 587 982 with an RR of 3·0. INTERPRETATION: We provide policy makers, researchers, and the public a simple model and an online tool for understanding excess mortality over 1 year from the COVID-19 pandemic, based on age, sex, and underlying condition-specific estimates. These results signal the need for sustained stringent suppression measures as well as sustained efforts to target those at highest risk because of underlying conditions with a range of preventive interventions. Countries should assess the overall (direct and indirect) effects of the pandemic on excess mortality. FUNDING: National Institute for Health Research University College London Hospitals Biomedical Research Centre, Health Data Research UK
Synthesis and Characterization of Single-Phase Metal Dodecaboride Solid Solutions: Zr1–xYxB12 and Zr1–xUxB12
Single-phase metal dodecaboride solid solutions, Zr0.5Y0.5B12 and Zr0.5U0.5B12, were prepared by arc melting from pure elements. The phase purity and composition were established by powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and 10B and 11B solid-state nuclear magnetic resonance (NMR) spectroscopy. The effects of carbon addition to Zr1–xYxB12 were studied and it was found that carbon causes fast cooling and as a result rapid nucleation of grains, as well as “templating” and patterning effects of the surface morphology. The hardness of the Zr0.5Y0.5B12 phase is 47.6 ± 1.7 GPa at 0.49 N load, which is ∼17% higher than that of its parent compounds, ZrB12 and YB12, with hardness values of 41.6 ± 2.6 and 37.5 ± 4.3 GPa, respectively. The hardness of Zr0.5U0.5B12 is ∼54% higher than that of its UB12 parent. The dodecaborides were confirmed to be metallic by band structure calculations, diffuse reflectance UV–vis, and solid-state NMR spectroscopies. The nature of the dodecaboride colors—violet for ZrB12 and blue for YB12—can be attributed to charge-transfer. XPS indicates that the metals are in the following oxidation states: Y3+, Zr4+, and U5+/6+. The superconducting transition temperatures (Tc) of the dodecaborides were determined to be 4.5 and 6.0 K for YB12 and ZrB12, respectively, as shown by resistivity and superconducting quantum interference device (SQUID) measurements. The Tc of the Zr0.5Y0.5B12 solid solution was suppressed to 2.5 K
Computer-aided screening of aspiration risks in dysphagia with wearable technology: a Systematic Review and meta-analysis on test accuracy
Aspiration caused by dysphagia is a prevalent problem that causes serious health consequences and even death. Traditional diagnostic instruments could induce pain, discomfort, nausea, and radiation exposure. The emergence of wearable technology with computer-aided screening might facilitate continuous or frequent assessments to prompt early and effective management. The objectives of this review are to summarize these systems to identify aspiration risks in dysphagic individuals and inquire about their accuracy. Two authors independently searched electronic databases, including CINAHL, Embase, IEEE Xplore® Digital Library, PubMed, Scopus, and Web of Science (PROSPERO reference number: CRD42023408960). The risk of bias and applicability were assessed using QUADAS-2. Nine (n = 9) articles applied accelerometers and/or acoustic devices to identify aspiration risks in patients with neurodegenerative problems (e.g., dementia, Alzheimer’s disease), neurogenic problems (e.g., stroke, brain injury), in addition to some children with congenital abnormalities, using videofluoroscopic swallowing study (VFSS) or fiberoptic endoscopic evaluation of swallowing (FEES) as the reference standard. All studies employed a traditional machine learning approach with a feature extraction process. Support vector machine (SVM) was the most famous machine learning model used. A meta-analysis was conducted to evaluate the classification accuracy and identify risky swallows. Nevertheless, we decided not to conclude the meta-analysis findings (pooled diagnostic odds ratio: 21.5, 95% CI, 2.7–173.6) because studies had unique methodological characteristics and major differences in the set of parameters/thresholds, in addition to the substantial heterogeneity and variations, with sensitivity levels ranging from 21.7% to 90.0% between studies. Small sample sizes could be a critical problem in existing studies (median = 34.5, range 18–449), especially for machine learning models. Only two out of the nine studies had an optimized model with sensitivity over 90%. There is a need to enlarge the sample size for better generalizability and optimize signal processing, segmentation, feature extraction, classifiers, and their combinations to improve the assessment performance.Systematic Review Registration: (https://www.crd.york.ac.uk/prospero/), identifier (CRD42023408960)
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