236 research outputs found

    Laser operation of a Tm:Y<sub>2</sub>O<sub>3</sub> planar waveguide

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    We demonstrate the first Tm-doped yttria planar waveguide laser to our knowledge, grown by pulsed laser deposition. A maximum output power of 35 mW at 1.95 µm with 9% slope efficiency was achieved from a 12 µm-thick film grown on a Y3Al5O12 substrate

    An 11.5 W Yb:YAG planar waveguide laser fabricated via pulsed laser deposition

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    We present details of the homo-epitaxial growth of Yb:YAG onto a &lt;100&gt; oriented YAG substrate by pulsed laser deposition. Material characterization and initial laser experiments are also reported, including the demonstration of laser action from the 15 µm-thick planar waveguide generating 11.5 W of output power with a slope efficiency of 48%. This work indicates that under appropriate conditions, high-quality single-crystal Yb:YAG growth via pulsed laser deposition is achievable with characteristics comparable to those obtained via conventional crystal growth techniques

    Theory of Distinct Crystal Structures of Polymerized Fullerides AC60, A=K, Rb, Cs: the Specific Role of Alkalis

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    The polymer phases of AC60 form distinct crystal structures characterized by the mutual orientations of the (C60-)n chains. We show that the direct electric quadrupole interaction between chains always favors the orthorhombic structure Pmnn with alternating chain orientations. However the specific quadrupolar polarizability of the alkali metal ions leads to an indirect interchain coupling which favors the monoclinic structure I2/m with equal chain orientations. The competition between direct and indirect interactions explains the structural difference between KC60 and RbC60, CsC60.Comment: 4 pages, 2 figures, 1 tabl

    Pregnancy outcomes in women with cardiovascular disease: evolving trends over 10 years in the ESC Registry Of Pregnancy And Cardiac disease (ROPAC)

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    Aims Reducing maternal mortality is a World Health Organization (WHO) global health goal. Although maternal deaths due to haemorrhage and infection are declining, those related to heart disease are increasing and are now the most important cause in western countries. The aim is to define contemporary diagnosis-specific outcomes in pregnant women with heart disease. Methods and results From 2007 to 2018, pregnant women with heart disease were prospectively enrolled in the Registry Of Pregnancy And Cardiac disease (ROPAC). Primary outcome was maternal mortality or heart failure, secondary outcomes were other cardiac, obstetric, and foetal complications. We enrolled 5739 pregnancies; the mean age was 29.5. Prevalent diagnoses were congenital (57%) and valvular heart disease (29%). Mortality (overall 0.6%) was highest in the pulmonary arterial hypertension (PAH) group (9%). Heart failure occurred in 11%, arrhythmias in 2%. Delivery was by Caesarean section in 44%. Obstetric and foetal complications occurred in 17% and 21%, respectively. The number of high-risk pregnancies (mWHO Class IV) increased from 0.7% in 2007–2010 to 10.9% in 2015–2018. Determinants for maternal complications were pre-pregnancy heart failure or New York Heart Association >II, systemic ejection fraction <40%, mWHO Class 4, and anticoagulants use. After an increase from 2007 to 2009, complication rates fell from 13.2% in 2010 to 9.3% in 2017. Conclusion Rates of maternal mortality or heart failure were high in women with heart disease. However, from 2010, these rates declined despite the inclusion of more high-risk pregnancies. Highest complication rates occurred in women with PAH

    2-Hour Accelerated Diagnostic Protocol to Assess Patients With Chest Pain Symptoms Using Contemporary Troponins as the Only Biomarker

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    Objectives The purpose of this study was to determine whether a new accelerated diagnostic protocol (ADP) for possible cardiac chest pain could identify low-risk patients suitable for early discharge (with follow-up shortly after discharge). Background Patients presenting with possible acute coronary syndrome (ACS), who have a low short-term risk of adverse cardiac events may be suitable for early discharge and shorter hospital stays. Methods This prospective observational study tested an ADP that included pre-test probability scoring by the Thrombolysis In Myocardial Infarction (TIMI) score, electrocardiography, and 0 + 2 h values of laboratory troponin I as the sole biomarker. Patients presenting with chest pain due to suspected ACS were included. The primary endpoint was major adverse cardiac event (MACE) within 30 days. Results Of 1,975 patients, 302 (15.3%) had a MACE. The ADP classified 392 patients (20%) as low risk. One (0.25%) of these patients had a MACE, giving the ADP a sensitivity of 99.7% (95% confidence interval [CI]: 98.1% to 99.9%), negative predictive value of 99.7% (95% CI: 98.6% to 100.0%), specificity of 23.4% (95% CI: 21.4% to 25.4%), and positive predictive value of 19.0% (95% CI: 17.2% to 21.0%). Many ADP negative patients had further investigations (74.1%), and therapeutic (18.3%) or procedural (2.0%) interventions during the initial hospital attendance and/or 30-day follow-up. Conclusions Using the ADP, a large group of patients was successfully identified as at low short-term risk of a MACE and therefore suitable for rapid discharge from the emergency department with early follow-up. This approach could decrease the observation period required for some patients with chest pain. (An observational study of the diagnostic utility of an accelerated diagnostic protocol using contemporary central laboratory cardiac troponin in the assessment of patients presenting to two Australasian hospitals with chest pain of possible cardiac origin; ACTRN12611001069943

    Cost-Effectiveness of Highly Active Antiretroviral Therapy in South Africa

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    BACKGROUND: Little information exists on the impact of highly active antiretroviral therapy (HAART) on health-care provision in South Africa despite increasing scale-up of access to HAART and gradual reduction in HAART prices. METHODS AND FINDINGS: Use and cost of services for 265 HIV-infected adults without AIDS (World Health Organization [WHO] stage 1, 2, or 3) and 27 with AIDS (WHO stage 4) receiving HAART between 1995 and 2000 in Cape Town were compared with HIV-infected controls matched for baseline WHO stage, CD4 count, age, and socioeconomic status, who did not receive antiretroviral therapy (ART; No-ART group). Costs of service provision (January 2004 prices, US1=7.6Rand)includedlocalunitcosts,andtwoscenariosforHAARTpricesforWHOrecommendedfirstlineregimens:scenario1usedcurrentSouthAfricanpublicsectorARTdrugpricesof1 = 7.6 Rand) included local unit costs, and two scenarios for HAART prices for WHO recommended first-line regimens: scenario 1 used current South African public-sector ART drug prices of 730 per patient-year (PPY), whereas scenario 2 was based on the anticipated public-sector price for locally manufactured drug of 181PPY.AllanalysesarepresentedintermsofpatientswithoutAIDSandpatientswithAIDS.ForpatientswithoutAIDS,themeannumberofinpatientdaysPPYwas1.08(95181 PPY. All analyses are presented in terms of patients without AIDS and patients with AIDS. For patients without AIDS, the mean number of inpatient days PPY was 1.08 (95% confidence interval [CI]: 0.97–1.19) for the HAART group versus 3.73 (95% CI: 3.55–3.97) for the No-ART group, and 8.71 (95% CI: 8.40–9.03) versus 4.35 (95% CI: 4.12–5.61), respectively, for mean number of outpatient visits PPY. Average service provision PPY was 950 for the No-ART group versus 1,342and1,342 and 793 PPY for the HAART group for scenario 1 and 2, respectively, whereas the incremental cost per life-year gained (LYG) was 1,622forscenario1and1,622 for scenario 1 and 675 for scenario 2. For patients with AIDS, mean inpatients days PPY was 2.04 (95% CI: 1.63–2.52) for the HAART versus 15.36 (95% CI: 13.97–16.85) for the No-ART group. Mean outpatient visits PPY was 7.62 (95% CI: 6.81–8.49) compared with 6.60 (95% CI: 5.69–7.62) respectively. Average service provision PPY was 3,520fortheNoARTgroupversus3,520 for the No-ART group versus 1,513 and 964fortheHAARTgroupforscenario1and2,respectively,whereastheincrementalcostperLYGwascostsavingforbothscenarios.Inasensitivityanalysisbasedonthelower(25964 for the HAART group for scenario 1 and 2, respectively, whereas the incremental cost per LYG was cost saving for both scenarios. In a sensitivity analysis based on the lower (25%) and upper (75%) interquartile range survival percentiles, the incremental cost per LYG ranged from 1,557 to 1,772forthegroupwithoutAIDSandfromcostsavingto1,772 for the group without AIDS and from cost saving to 111 for patients with AIDS. CONCLUSION: HAART is a cost-effective intervention in South Africa, and cost saving when HAART prices are further reduced. Our estimates, however, were based on direct costs, and as such the actual cost saving might have been underestimated if indirect costs were also included

    Rapid Rule-out of Acute Myocardial Infarction With a Single High-Sensitivity Cardiac Troponin T Measurement Below the Limit of Detection: A Collaborative Meta-analysis.

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    Background: High-sensitivity assays for cardiac troponin T (hs-cTnT) are sometimes used to rapidly rule out acute myocardial infarction (AMI). Purpose: To estimate the ability of a single hs-cTnT concentration below the limit of detection (<0.005 µg/L) and a nonischemic electrocardiogram (ECG) to rule out AMI in adults presenting to the emergency department (ED) with chest pain. Data Sources: EMBASE and MEDLINE without language restrictions (1 January 2008 to 14 December 2016). Study Selection: Cohort studies involving adults presenting to the ED with possible acute coronary syndrome in whom an ECG and hs-cTnT measurements were obtained and AMI outcomes adjudicated during initial hospitalization. Data Extraction: Investigators of studies provided data on the number of low-risk patients (no new ischemia on ECG and hs-cTnT measurements <0.005 µg/L) and the number who had AMI during hospitalization (primary outcome) or a major adverse cardiac event (MACE) or death within 30 days (secondary outcomes), by risk classification (low or not low risk). Two independent epidemiologists rated risk of bias of studies. Data Synthesis: Of 9241 patients in 11 cohort studies, 2825 (30.6%) were classified as low risk. Fourteen (0.5%) low-risk patients had AMI. Sensitivity of the risk classification for AMI ranged from 87.5% to 100% in individual studies. Pooled estimated sensitivity was 98.7% (95% CI, 96.6% to 99.5%). Sensitivity for 30-day MACEs ranged from 87.9% to 100%; pooled sensitivity was 98.0% (CI, 94.7% to 99.3%). No low-risk patients died. Limitation: Few studies, variation in timing and methods of reference standard troponin tests, and heterogeneity of risk and prevalence of AMI across studies. Conclusion: A single hs-cTnT concentration below the limit of detection in combination with a nonischemic ECG may successfully rule out AMI in patients presenting to EDs with possible emergency acute coronary syndrome. Primary Funding Source: Emergency Care Foundation

    Personalized diagnosis in suspected myocardial infarction

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    Background: In suspected myocardial infarction (MI), guidelines recommend using high-sensitivity cardiac troponin (hscTn)- based approaches. These require fixed assay-specific thresholds and timepoints, without directly integrating clinical information. Using machine-learning techniques including hs-cTn and clinical routine variables, we aimed to build a digital tool to directly estimate the individual probability of MI, allowing for numerous hs-cTn assays. Methods: In 2,575 patients presenting to the emergency department with suspected MI, two ensembles of machine-learning models using single or serial concentrations of six different hs-cTn assays were derived to estimate the individual MI probability ( ARTEMIS model). Discriminative performance of the models was assessed using area under the receiver operating characteristic curve (AUC) and logLoss. Model performance was validated in an external cohort with 1688 patients and tested for global generalizability in 13 international cohorts with 23,411 patients. Results: Eleven routinely available variables including age, sex, cardiovascular risk factors, electrocardiography, and hs-cTn were included in the ARTEMIS models. In the validation and generalization cohorts, excellent discriminative performance was confirmed, superior to hs-cTn only. For the serial hs-cTn measurement model, AUC ranged from 0.92 to 0.98. Good calibration was observed. Using a single hs-cTn measurement, the ARTEMIS model allowed direct rule-out of MI with very high and similar safety but up to tripled efficiency compared to the guideline- recommended strategy. Conclusion We developed and validated diagnostic models to accurately estimate the individual probability of MI, which allow for variable hs-cTn use and flexible timing of resampling. Their digital application may provide rapid, safe and efficient personalized patient care

    Physical health behaviours and health locus of control in people with schizophrenia-spectrum disorder and bipolar disorder: a cross-sectional comparative study with people with non-psychotic mental illness

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    <p>Abstract</p> <p>Background</p> <p>People with mental illness experience high levels of morbidity and mortality from physical disease compared to the general population. Our primary aim was to compare how people with severe mental illness (SMI; i.e. schizophrenia-spectrum disorders and bipolar disorder) and non-psychotic mental illness perceive their: (i) global physical health, (ii) barriers to improving physical health, (iii) physical health with respect to important aspects of life and (iv) motivation to change modifiable high-risk behaviours associated with coronary heart disease. A secondary aim was to determine health locus of control in these two groups of participants.</p> <p>Methods</p> <p>People with SMI and non-psychotic mental illness were recruited from an out-patient adult mental health service in London. Cross-sectional comparison between the two groups was conducted by means of a self-completed questionnaire.</p> <p>Results</p> <p>A total of 146 people participated in the study, 52 with SMI and 94 with non-psychotic mental illness. There was no statistical difference between the two groups with respect to the perception of global physical health. However, physical health was considered to be a less important priority in life by people with SMI (OR 0.5, 95% CI 0.2-0.9, <it>p </it>= 0.029). There was no difference between the two groups in their desire to change high risk behaviours. People with SMI are more likely to have a health locus of control determined by powerful others (<it>p </it>< 0.001) and chance (<it>p </it>= 0.006).</p> <p>Conclusions</p> <p>People with SMI appear to give less priority to their physical health needs. Health promotion for people with SMI should aim to raise awareness of modifiable high-risk lifestyle factors. Findings related to locus of control may provide a theoretical focus for clinical intervention in order to promote a much needed behavioural change in this marginalised group of people.</p
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