227,743 research outputs found
The Quantitative Effect of Noise and Object Diameter on Low-Contrast Detectability of AAPM CT Performance Phantom Images
Parameters for determining computed tomography (CT) image quality include noise and low-contrast detectability. Studies on low-contrast detectability using the AAPM CT performance phantom have several limitations, such as the absence of quantitative information on the effect of noise and object size on low-contrast detectability. In this study, the quantitative effect of noise and object diameter on low-contrast detectability were investigated. Images of the American Association of Physicists in Medicine (AAPM) CT performance phantom model 610 were acquired with a tube voltage of 120 kV and tube currents of 50, 100, 150, and 200 mA. The low-contrast section of the AAPM CT performance phantom model 610 has objects with diameters between 2.5 and 7.5 mm. We analysed the mean CT number, noise level, signal-to noise ratio (SNR), and contrast-to-noise ratio (CNR), acquired using MatLab software. The results obtained indicate that noise and object size affect low-contrast detectability. The CNRs increase linearly with increasing of object diameter with R2 of 0.88, 0.67, 0.75, and 0.83 for tube currents of 50, 100, 150 and 200 mA, respectively
Prevalence of internet addiction disorder in Chinese university students: A comprehensive meta-analysis of observational studies
Background and aims: Internet addiction disorder (IAD) is common in university students. A number of studies have examined the prevalence of IAD in Chinese university students, but the results have been inconsistent. This is a meta-analysis of the prevalence of IAD and its associated factors in Chinese university students.
Methods: Both English (PubMed, PsycINFO, and Embase) and Chinese (Wan Fang Database and Chinese National Knowledge Infrastructure) databases were systematically and independently searched from their inception until January 16, 2017.
Results: Altogether 70 studies covering 122,454 university students were included in the meta-analysis. Using the random-effects model, the pooled overall prevalence of IAD was 11.3% (95% CI: 10.1%ā12.5%). When using the 8-item Young Diagnostic Questionnaire, the 10-item modified Young Diagnostic Questionnaire, the 20-item Internet Addiction Test, and the 26-item Chen Internet Addiction Scale, the pooled prevalence of IAD was 8.4% (95% CI: 6.7%ā10.4%), 9.3% (95% CI: 7.6%ā11.4%), 11.2% (95% CI: 8.8%ā14.3%), and 14.0% (95% CI: 10.6%ā18.4%), respectively. Subgroup analyses revealed that the pooled prevalence of IAD was significantly associated with the measurement instrument (Q = 9.41, p = .024). Male gender, higher grade, and urban abode were also significantly associated with IAD. The prevalence of IAD was also higher in eastern and central of China than in its northern and western regions (10.7% vs. 8.1%, Q = 4.90, p = .027).
Conclusions: IAD is common among Chinese university students. Appropriate strategies for the prevention and treatment of IAD in this population need greater attention
Coronary-artery bypass surgery in patients with ischemic cardiomyopathy
BACKGROUND
The survival benefit of a strategy of coronary-artery bypass grafting (CABG) added to
guideline-directed medical therapy, as compared with medical therapy alone, in patients
with coronary artery disease, heart failure, and severe left ventricular systolic
dysfunction remains unclear.
METHODS
From July 2002 to May 2007, a total of 1212 patients with an ejection fraction of 35%
or less and coronary artery disease amenable to CABG were randomly assigned to
undergo CABG plus medical therapy (CABG group, 610 patients) or medical therapy
alone (medical-therapy group, 602 patients). The primary outcome was death from any
cause. Major secondary outcomes included death from cardiovascular causes and death
from any cause or hospitalization for cardiovascular causes. The median duration of
follow-up, including the current extended-follow-up study, was 9.8 years.
RESULTS
A primary outcome event occurred in 359 patients (58.9%) in the CABG group and in
398 patients (66.1%) in the medical-therapy group (hazard ratio with CABG vs. medical
therapy, 0.84; 95% confidence interval [CI], 0.73 to 0.97; P=0.02 by log-rank test). A
total of 247 patients (40.5%) in the CABG group and 297 patients (49.3%) in the
medical-therapy group died from cardiovascular causes (hazard ratio, 0.79; 95% CI,
0.66 to 0.93; P=0.006 by log-rank test). Death from any cause or hospitalization for
cardiovascular causes occurred in 467 patients (76.6%) in the CABG group and in 524
patients (87.0%) in the medical-therapy group (hazard ratio, 0.72; 95% CI, 0.64 to 0.82;
P<0.001 by log-rank test).
CONCLUSIONS
In a cohort of patients with ischemic cardiomyopathy, the rates of death from any
cause, death from cardiovascular causes, and death from any cause or hospitalization
for cardiovascular causes were significantly lower over 10 years among patients who
underwent CABG in addition to receiving medical therapy than among those who received
medical therapy alone. (Funded by the National Institutes of Health; STICH [and
STICHES] ClinicalTrials.gov number, NCT00023595.
Text Analytics for Android Project
Most advanced text analytics and text mining tasks include text classification, text clustering, building ontology, concept/entity extraction, summarization, deriving patterns within the structured data, production of granular taxonomies, sentiment and emotion analysis, document summarization, entity relation modelling, interpretation of the output. Already existing text analytics and text mining cannot develop text material alternatives (perform a multivariant design), perform multiple criteria analysis,
automatically select the most effective variant according to different aspects (citation index of papers (Scopus, ScienceDirect, Google Scholar) and authors (Scopus, ScienceDirect, Google Scholar), Top 25 papers, impact factor of journals, supporting phrases, document name and contents, density of keywords), calculate utility degree and market value. However, the Text Analytics for Android Project can perform the aforementioned functions. To the best of the knowledge herein, these functions have not been previously implemented; thus this is the first attempt to do so. The Text Analytics for Android Project is briefly described in this article
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Cardiac Biomarkers and Risk of Atrial Fibrillation in Chronic Kidney Disease: The CRIC Study.
Background We tested associations of cardiac biomarkers of myocardial stretch, injury, inflammation, and fibrosis with the risk of incident atrial fibrillation (AF) in a prospective study of chronic kidney disease patients. Methods and Results The study sample was 3053 participants with chronic kidney disease in the multicenter CRIC (Chronic Renal Insufficiency Cohort) study who were not identified as having AF at baseline. Cardiac biomarkers, measured at baseline, were NT-proBNP (N-terminal pro-B-type natriuretic peptide), high-sensitivity troponin T, galectin-3, growth differentiation factor-15, and soluble ST-2. Incident AF ("AF event") was defined as a hospitalization for AF. During a median follow-up of 8Ā years, 279 (9%) participants developed a new AF event. In adjusted models, higher baseline log-transformed NT-proBNP (N-terminal pro-B-type natriuretic peptide) was associated with incident AF (adjusted hazard ratio [HR] per SD higher concentration: 2.11; 95% CI, 1.75, 2.55), as was log-high-sensitivity troponin T (HR 1.42; 95% CI, 1.20, 1.68). These associations showed a dose-response relationship in categorical analyses. Although log-soluble ST-2 was associated with AF risk in continuous models (HR per SD higher concentration 1.35; 95% CI, 1.16, 1.58), this association was not consistent in categorical analyses. Log-galectin-3 (HR 1.05; 95% CI, 0.91, 1.22) and log-growth differentiation factor-15 (HR 1.16; 95% CI, 0.96, 1.40) were not significantly associated with incident AF. Conclusions We found strong associations between higher NT-proBNP (N-terminal pro-B-type natriuretic peptide) and high-sensitivity troponin T concentrations, and the risk of incident AF in a large cohort of participants with chronic kidney disease. Increased atrial myocardial stretch and myocardial cell injury may be implicated in the high burden of AF in patients with chronic kidney disease
Genetic risk factors for ischaemic stroke and its subtypes (the METASTROKE Collaboration): a meta-analysis of genome-wide association studies
<p>Background - Various genome-wide association studies (GWAS) have been done in ischaemic stroke, identifying a few loci associated with the disease, but sample sizes have been 3500 cases or less. We established the METASTROKE collaboration with the aim of validating associations from previous GWAS and identifying novel genetic associations through meta-analysis of GWAS datasets for ischaemic stroke and its subtypes.</p>
<p>Methods - We meta-analysed data from 15 ischaemic stroke cohorts with a total of 12ā389 individuals with ischaemic stroke and 62ā004 controls, all of European ancestry. For the associations reaching genome-wide significance in METASTROKE, we did a further analysis, conditioning on the lead single nucleotide polymorphism in every associated region. Replication of novel suggestive signals was done in 13ā347 cases and 29ā083 controls.</p>
<p>Findings - We verified previous associations for cardioembolic stroke near PITX2 (p=2Ā·8Ć10ā16) and ZFHX3 (p=2Ā·28Ć10ā8), and for large-vessel stroke at a 9p21 locus (p=3Ā·32Ć10ā5) and HDAC9 (p=2Ā·03Ć10ā12). Additionally, we verified that all associations were subtype specific. Conditional analysis in the three regions for which the associations reached genome-wide significance (PITX2, ZFHX3, and HDAC9) indicated that all the signal in each region could be attributed to one risk haplotype. We also identified 12 potentially novel loci at p<5Ć10ā6. However, we were unable to replicate any of these novel associations in the replication cohort.</p>
<p>Interpretation - Our results show that, although genetic variants can be detected in patients with ischaemic stroke when compared with controls, all associations we were able to confirm are specific to a stroke subtype. This finding has two implications. First, to maximise success of genetic studies in ischaemic stroke, detailed stroke subtyping is required. Second, different genetic pathophysiological mechanisms seem to be associated with different stroke subtypes.</p>
Effects of precipitation conditions on the membrane morphology and permeation characteristics
[[abstract]]The permeability and permselectivity of asymmetric and particulate membranes towards glucose and proteins of various molecular sizes were studied. It was found that the skin layer of asymmetric membranes was permeable to glucose and insulin but effectively prevent the permeation of immunoglobulins. This result parallels our interest for the development of artificial pancreas. It was also found that skinless particulate membranes exhibited not only high permeation rates with respect to albumin and immunoglobulins but also good selectivity between these components. Thus, particulate membranes has the potential to be used in separating albumin from immunoglobulins for treating disorders related to immunoglobulin abnormalities.[[notice]]č£ę£å®ē¢[[journaltype]]åå¤[[incitationindex]]SCI[[incitationindex]]E
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Analyzing Chinaās contributions to major dermatologic journals from the past 20 years
Background: Over the past 20 years, China has experienced an increased popularity of Western medicine. The impact of Western medicine in China on the field of dermatology is not well characterized. Objective: To assess the impact China has had on the field of dermatology by analyzing the total publications to six dermatological journals, compared to two other Asian countries: Japan and Korea. Methods: PubMed was utilized to search for publications from China, Japan, and Korea within the past 20 years. Descriptive statistics were used to determine the average percentage change in publications during this 20-year period, and the average annual increase in total number of publications from each country. Comparisons were made using one-way ANOVA and two-group t-tests. Results: From 1998 to 2019, there was a 24% average annual increase in publications from China (M=24.4, SD=24.5), compared to a 6% increase from Japan (M=5.6, SD=25.4, P=0.02) and 8% increase from Korea (M=7.8, SD=23.4, P=0.03). Conclusion: For the past 20 years, there has been a strong positive trend regarding the total number of publications from China. This finding might be related in part to an increased acceptance of Western medicine, which follows a similar trend during the time period we analyzed
Analysis of pregnancy-associated plasma protein a production in human adult cardiac progenitor cells
IGF-binding proteins (IGFBPs) and their proteases regulate IGFs bioavailability in multiple tissues. Pregnancy-associated plasma protein A (PAPP-A) is a protease acting by cleaving IGFBP2, 4, and 5, regulating local bioavailability of IGFs. We have previously shown that IGFs and IGFBPs are produced by human adult cardiac progenitor cells (haCPCs) and that IGF-1 exerts paracrine therapeutic effects in cardiac cell therapy with CPCs. Using immunofluorescence and enzyme immunoassays, we firstly report that PAPP-A is produced and secreted in surprisingly high amounts by haCPCs. In particular, the homodimeric, enzymatically active, PAPP-A is secreted in relevant concentrations in haCPC-conditioned media, while the enzymatically inactive PAPPA/proMBP complex is not detectable in the same media. Furthermore, we show that both homodimeric PAPP-A and proMBP can be detected as cell associated, suggesting that the previously described complex formation at the cell surface does not occur easily, thus positively affecting IGF signalling. Therefore, our results strongly support the importance of PAPP-A for the IGFs/IGFBPs/PAPP-A axis in CPCs biology
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Magnitude of the Difference Between Clinic and Ambulatory Blood Pressures and Risk of Adverse Outcomes in Patients With Chronic Kidney Disease.
Background Obtaining 24-hour ambulatory blood pressure ( BP ) is recommended for the detection of masked or white-coat hypertension. Our objective was to determine whether the magnitude of the difference between ambulatory and clinic BP s has prognostic implications. Methods and Results We included 610 participants of the AASK (African American Study of Kidney Disease and Hypertension) Cohort Study who had clinic and ambulatory BPs performed in close proximity in time. We used Cox models to determine the association between the absolute systolic BP ( SBP ) difference between clinic and awake ambulatory BPs (primary predictor) and death and end-stage renal disease. Of 610 AASK Cohort Study participants, 200 (32.8%) died during a median follow-up of 9.9 years; 178 (29.2%) developed end-stage renal disease. There was a U-shaped association between the clinic and ambulatory SBP difference with risk of death, but not end-stage renal disease. A 5- to <10-mm Hg higher clinic versus awake SBP (white-coat effect) was associated with a trend toward higher (adjusted) mortality risk (adjusted hazard ratio, 1.84; 95% CI, 0.94-3.56) compared with a 0- to <5-mm Hg clinic-awake SBP difference (reference group). A ā„10-mm Hg clinic-awake SBP difference was associated with even higher mortality risk (adjusted hazard ratio, 2.31; 95% CI, 1.27-4.22). A ā„-5-mm Hg clinic-awake SBP difference was also associated with higher mortality (adjusted hazard ratio, 1.82; 95% CI, 1.05-3.15) compared with the reference group. Conclusions A U-shaped association exists between the magnitude of the difference between clinic and ambulatory SBP and mortality. Higher clinic versus ambulatory BPs (as in white-coat effect) may be associated with higher risk of death in black patients with chronic kidney disease
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