5,474 research outputs found

    Flow dynamics and mixing past pairs of confined microfluidic cylinders

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    Placing cylindrical obstacles in a micromixer is a promising means to enhance mass transport. However, there is still a lack of fundamental understanding on the effect of obstacle arrangement on the flow. The present work provides new experimental insights into confined inertia flows past two cylindrical pins, placed either in tandem or staggered arrangement in a Y-type micromixer, and their effect on mixing, through micro Particle Image Velocimetry (μPIV) and Laser Induced Fluorescence (μLIF) measurements. It is found that in such confined microfluidic environments, adding a second pin suppresses vortex-shedding for spacings less than 3.5-pin diameters in a tandem arrangement or 0.25-pin diameters in the staggered configurations. Vortex-shedding is found to enhance mixing in tandem configurations but not in staggered ones. The results highlight the important roles of both pin arrangement and flow instabilities in micromixer performance and can serve as a guide to micromixer design

    A decision support tool for health service re-design

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    Many of the outpatient services are currently only available in hospitals, however there are plans to provide some of these services alongside with General Practitioners. Consequently, General Practitioners could soon be based at polyclinics. These changes have caused a number of concerns to Hounslow Primary Care Trust (PCT). For example, which of the outpatient services are to be shifted from the hospital to the polyclinic? What are the current and expected future demands for these services? To tackle some of these concerns, the first phase of this project explores the set of specialties that are frequently visited in a sequence (using sequential association rules). The second phase develops an Excel based spreadsheet tool to compute the current and expected future demands for the selected specialties. From the sequential association rule algorithm, endocrinology and ophthalmology were found to be highly associated (i.e. frequently visited in a sequence), which means that these two specialties could easily be shifted from the hospital environment to the polyclinic. We illustrated the Excel based spreadsheet tool for endocrinology and ophthalmology, however, the model is generic enough to cope with other specialties, provided that the data are available

    An automated vital sign monitoring system for congestive heart failure patients

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    Congestive heart failure (CHF) is a cardiovascular disorder that affects approximately 4.6 million Americans and is a leading cause of death in the United States. Current research shows that strategies to promote early recognition and treatment of symptoms and enhance self-care management behaviors reduce unnecessary hospitalizations. However, mechanisms to monitor patients' health status and behaviors are limited by constraints imposed by the patient's geography, infirmity, or resources. Remote monitoring supports a more dynamic connection between healthcare providers and patients, improves health promotion and patient care through monitoring of health data, communicates health reminders, and makes provisions for patient feedback. This paper will describe two versions of Weight and Activity with Blood Pressure Monitoring System (WANDA [22]) that leverages sensor technology and wireless communication to monitor health status of patients with CHF. The WANDA system is built on a three-tier architecture consisting of sensors, a web server, and back-end database tiers. The system was developed in conjunction with the UCLA School of Nursing and the UCLA Wireless Health Institute to enable early detection of key clinical symptoms indicative of CHF-related decompensation in a real-time automated fashion and allows health professionals to offer surveillance, advice, and continuity of care and triggers early implementation of strategies to enhance adherence behaviors. The small study has enabled patients to reduce or maintain the number of readings which are out of the acceptable range. For diastolic, systolic, and heart rate values, the t-test results show that the WANDA study is effective for patients with CHF. © 2010 ACM

    Quantum corrections and black hole spectroscopy

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    In the work \cite{BRM,RBE}, black hole spectroscopy has been successfully reproduced in the tunneling picture. As a result, the derived entropy spectrum of black hole in different gravity (including Einstein's gravity, Einstein-Gauss-Bonnet gravity and Ho\v{r}ava-Lifshitz gravity) are all evenly spaced, sharing the same forms as Sn=nS_n=n, where physical process is only confined in the semiclassical framework. However, the real physical picture should go beyond the semiclassical approximation. In this case, the physical quantities would undergo higher-order quantum corrections, whose effect on different gravity shares in different forms. Motivated by these facts, in this paper we aim to observe how quantum corrections affect black hole spectroscopy in different gravity. The result shows that, in the presence of higher-order quantum corrections, black hole spectroscopy in different gravity still shares the same form as Sn=nS_n=n, further confirming the entropy quantum is universal in the sense that it is not only independent of black hole parameters, but also independent of higher-order quantum corrections. This is a desiring result for the forthcoming quantum gravity theory.Comment: 14 pages, no figure, use JHEP3.cls. to be published in JHE

    The Effect of ICS Withdrawal and Baseline Inhaled Treatment on Exacerbations in the IMPACT Study: A Randomized, Double-blind Multicenter Trial

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    RATIONALE: In the IMPACT trial fluticasone furoate/umeclidinium/ vilanterol (FF/UMEC/VI) significantly reduced exacerbations compared with FF/VI or UMEC/VI in patients with symptomatic chronic obstructive pulmonary disease and a history of exacerbations. OBJECTIVES: Understand whether inhaled corticosteroid (ICS) withdrawal affected IMPACT results given direct transition from prior maintenance medication to study medication at randomization. METHODS: Exacerbations and change from baseline in trough forced expiratory volume in 1 second (FEV1) and St George's Respiratory Questionnaire (SGRQ) were analyzed by prior ICS use. Exacerbations were also analyzed excluding data from the first 30 days. MEASUREMENTS AND MAIN RESULTS: FF/UMEC/VI significantly reduced annual moderate/severe exacerbation rate versus UMEC/VI in prior ICS users (29% reduction; p<0.001), but only a numerical reduction was seen among prior ICS non-users (12% reduction; p=0.115). To minimize impact from ICS withdrawal, in an analysis excluding the first 30 days, FF/UMEC/VI continued to significantly reduce annual on-treatment moderate/severe exacerbation rate (19%; p<0.001) versus UMEC/VI. Benefit of FF/UMEC/VI versus UMEC/VI was seen for severe exacerbation rates, regardless of prior ICS use (prior ICS users: 35% reduction, p<0.001; non-ICS users: 35% reduction, p=0.018) and overall when excluding the first 30 days (29%, p<0.001). Improvements from baseline with FF/UMEC/VI versus UMEC/VI were also maintained throughout the study for both trough FEV1 and SGRQ regardless of prior ICS use. CONCLUSIONS: These data support important treatment effects from FF/UMEC/VI combination therapy on exacerbation reduction, lung function and quality of life that do not appear to be related to abrupt ICS withdrawal. FUNDING: GSK (CTT116855/NCT02164513). Clinical trial registration available at www.clinicaltrials.gov, ID: NCT02164513. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

    Light smoking at base-line predicts a higher mortality risk to women than to men; evidence from a cohort with long follow-up

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    BACKGROUND: There is conflicting evidence as to whether smoking is more harmful to women than to men. The UK Cotton Workers’ Cohort was recruited in the 1960s and contained a high proportion of men and women smokers who were well matched in terms of age, job and length of time in job. The cohort has been followed up for 42 years. METHODS: Mortality in the cohort was analysed using an individual relative survival method and Cox regression. Whether smoking, ascertained at baseline in the 1960s, was more hazardous to women than to men was examined by estimating the relative risk ratio women to men, smokers to never smoked, for light (1–14), medium (15–24), heavy (25+ cigarettes per day) and former smoking. RESULTS: For all-cause mortality relative risk ratios were 1.35 for light smoking at baseline (95% CI 1.07-1.70), 1.15 for medium smoking (95% CI 0.89-1.49) and 1.00 for heavy smoking (95% CI 0.63-1.61). Relative risk ratios for light smoking at baseline for circulatory system disease was 1.42 (95% CI 1.01 to 1.98) and for respiratory disease was 1.89 (95% CI 0.99 to 3.63). Heights of participants provided no explanation for the gender difference. CONCLUSIONS: Light smoking at baseline was shown to be significantly more hazardous to women than to men but the effect decreased as consumption increased indicating a dose response relationship. Heavy smoking was equally hazardous to both genders. This result may help explain the conflicting evidence seen elsewhere. However gender differences in smoking cessation may provide an alternative explanation

    Effect of Age on the Efficacy and Safety of Once-Daily Single-Inhaler Triple Therapy Fluticasone Furoate/Umeclidinium/Vilanterol in Patients With Chronic Obstructive Pulmonary Disease: A Post Hoc Analysis of the IMPACT Trial

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    BACKGROUND: In the IMPACT trial, single-inhaler triple therapy fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) reduced moderate/severe exacerbation rates versus FF/VI and UMEC/VI in patients with symptomatic chronic obstructive pulmonary disease (COPD) and a history of exacerbations, with a similar safety profile. Research Question Does age have an effect on trial outcomes? STUDY DESIGN AND METHODS: IMPACT was a Phase III, double-blind, 52-week trial. Patients ≥40 years of age with symptomatic COPD and ≥1 moderate/severe exacerbation in the prior year were randomized 2:2:1 to FF/UMEC/VI 100/62.5/25 mcg, FF/VI 100/25 mcg, or UMEC/VI 62.5/25 mcg. Endpoints assessed by age included annual rate of moderate/severe exacerbations, change from baseline (CFB) in trough forced expiratory volume in 1 second (FEV1), proportion of St George's Respiratory Questionnaire (SGRQ) responders (≥4 units decrease from baseline in SGRQ total score) and safety. RESULTS: The intent-to-treat population comprised 10,355 patients; 4724 (46%), 4225 (41%), and 1406 (14%) were ≤64, 65-74, and ≥75 years of age, respectively. FF/UMEC/VI reduced on-treatment moderate/severe exacerbation rates versus FF/VI (% reduction [95% confidence interval (CI)], ≤64 years: 8% [-1, 16], p=0.070; 65-74 years: 22% [14, 29], p<0.001; ≥75 years 18% [3, 31], p=0.021) and versus UMEC/VI (≤64 years: 16% [7, 25], p=0.002; 65-74 years: 33% [25, 41], p<0.001; ≥75 years 24% [6, 38], p=0.012), with greatest rate reduction seen in the 65-74 and ≥75 years subgroups. Post hoc analyses of CFB in trough FEV1, and proportion of SGRQ responders at Week 52 were significantly greater with FF/UMEC/VI than FF/VI or UMEC/VI in all subgroups. No new safety signals were identified. INTERPRETATION: FF/UMEC/VI reduced the rate of moderate/severe exacerbations and improved lung function and health status versus FF/VI and UMEC/VI irrespective of age for most endpoints, with a similar safety profile. CLINICAL TRIAL REGISTRATION: GSK (CTT116855/NCT02164513)

    Prognostic value of clinically important deterioration in COPD: IMPACT trial analysis

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    Introduction: Clinically important deterioration (CID) is a multicomponent measure for assessing disease worsening in chronic obstructive pulmonary disease (COPD). This analysis investigated the prognostic value of a CID event on future clinical outcomes and the effect of single-inhaler triple versus dual therapy on reducing CID risk in patients in the IMPACT trial. Methods: IMPACT was a phase III, double-blind, 52-week, multicentre trial. Patients with symptomatic COPD and at least one moderate/severe exacerbation in the prior year were randomised 2:2:1 to fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) 100/62.5/25 µg, FF/VI 100/25 µg or UMEC/VI 62.5/25 µg. CID at the time-point of interest was defined as a moderate/severe exacerbation, ≥100 mL decrease in trough forced expiratory volume in 1 s or deterioration in health status (increase of ≥4.0 units in St George's Respiratory Questionnaire total score or increase of ≥2.0 units in COPD Assessment Test score) from baseline. A treatment-independent post hoc prognostic analysis compared clinical outcomes up to week 52 in patients with/without a CID by week 28. A prospective analysis evaluated time to first CID with each treatment. Results: Patients with a CID by week 28 had significantly increased exacerbation rates after week 28, smaller improvements in lung function and health status at week 52 (all p<0.001), and increased risk of all-cause mortality after week 28 versus patients who were CID-free. FF/UMEC/VI significantly reduced CID risk versus dual therapies (all p<0.001). Conclusions: Prevention of short-term disease worsening was associated with better long-term clinical outcomes. FF/UMEC/VI reduced CID risk versus dual therapies; this effect may improve long-term prognosis in this population

    Inhibition of Cardiac Sympathetic Afferent Reflex and Sympathetic Activity by Baroreceptor and Vagal Afferent Inputs in Chronic Heart Failure

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    BACKGROUND: Cardiac sympathetic afferent reflex (CSAR) contributes to sympathetic activation and angiotensin II (Ang II) in paraventricular nucleus (PVN) augments the CSAR in vagotomized (VT) and baroreceptor denervated (BD) rats with chronic heart failure (CHF). This study was designed to determine whether it is true in intact (INT) rats with CHF and to determine the effects of cardiac and baroreceptor afferents on the CSAR and sympathetic activity in CHF. METHODOLOGY/PRINCIPAL FINDINGS: Sham-operated (Sham) or coronary ligation-induced CHF rats were respectively subjected to BD+VT, VT, cardiac sympathetic denervation (CSD) or INT. Under anesthesia, renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded, and the CSAR was evaluated by the RSNA and MAP responses to epicardial application of capsaicin. Either CSAR or the responses of RSNA, MAP and CSAR to Ang II in PVN were enhanced in CHF rats treated with BD+VT, VT or INT. Treatment with VT or BD+VT potentiated the CSAR and the CSAR responses to Ang II in both Sham and CHF rats. Treatment with CSD reversed the capsaicin-induced RSNA and MAP changes and the CSAR responses to Ang II in both Sham and CHF rats, and reduced the RSNA and MAP responses to Ang II only in CHF rats. CONCLUSIONS: The CSAR and the CSAR responses to Ang II in PVN are enhanced in intact CHF rats. Baroreceptor and vagal afferent activities inhibit CSAR and the CSAR responses to Ang II in intact Sham and CHF rats
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