168 research outputs found
The role of SiN/GaN cap interface charge and GaN cap layer to achieve enhancement mode GaN MIS-HEMT operation
The thickness increase of gallium nitride (GaN) cap layer from 2 nm to 35 nm to achieve an enhancement mode GaN MIS-HEMT (Metal-Insulator-Semiconductor High-Electron-Mobility Transistor) with a threshold voltage (Vth) of +0.5 V is studied using TCAD simulations. The simulations are calibrated to measured I-V characteristics of the 1 μm gate length GaN MIS-HEMT with the 2 nm thick GaN cap. A good agreement at low and high drain voltages (VDS=1 V and 5 V) between simulations and measurements is achieved by using a quantum-corrected drift-diffusion transport model. The enhancement mode GaN MIS-HEMT with a GaN cap thickness of 35 nm achieves Vth = + 0.5 V thanks to positive interface traps occurring between the SiN passivation layer and the GaN cap as reported experimentally. The simulations indicate that a parasitic channel is created at the interface between the SiN layer and the 35 nm GaN cap. Our study also shows an increase in the breakdown voltage from 100 V to 870 V when a thickness of the GaN cap layer increases from 15 nm to 35 nm
Role of human milk oligosaccharides in Group B Streptococcus colonisation.
Group B Streptococcus (GBS) infection is a major cause of morbidity and mortality in infants. The major risk factor for GBS disease is maternal and subsequent infant colonisation. It is unknown whether human milk oligosaccharides (HMOs) protect against GBS colonisation. HMO production is genetically determined and linked to the Lewis antigen system. We aimed to investigate the association between HMOs and infant GBS colonisation between birth and postnatal day 90. Rectovaginal swabs were collected at delivery, as well as colostrum/breast milk, infant nasopharyngeal and rectal swabs at birth, 6 days and days 60-89 postpartum from 183 Gambian mother/infant pairs. GBS colonisation and serotypes were determined using culture and PCR. (1)H nuclear magnetic resonance spectroscopy was used to characterise the mother's Lewis status and HMO profile in breast milk. Mothers who were Lewis-positive were significantly less likely to be colonised by GBS (X (2)=12.50, P<0.001). Infants of Lewis-positive mothers were less likely GBS colonised at birth (X (2)=4.88 P=0.03) and more likely to clear colonisation between birth and days 60-89 than infants born to Lewis-negative women (P=0.05). There was no association between Secretor status and GBS colonisation. In vitro work revealed that lacto-N-difucohexaose I (LNDFHI) correlated with a reduction in the growth of GBS. Our results suggest that HMO such as LNDFHI may be a useful adjunct in reducing maternal and infant colonisation and hence invasive GBS disease. Secretor status offers utility as a stratification variable in GBS clinical trials
Six-minute walk distance after coronary artery bypass grafting compared with medical therapy in ischaemic cardiomyopathy
Background: In patients with ischaemic left ventricular dysfunction, coronary artery bypass surgery (CABG) may decrease mortality, but it is not known whether CABG improves functional capacity.
Objective: To determine whether CABG compared with medical therapy alone (MED) increases 6 min walk distance in patients with ischaemic left ventricular dysfunction and coronary artery disease amenable to revascularisation.
Methods: The Surgical Treatment in Ischemic Heart disease trial randomised 1212 patients with ischaemic left ventricular dysfunction to CABG or MED. A 6 min walk distance test was performed both at baseline and at least one follow-up assessment at 4, 12, 24 and/or 36 months in 409 patients randomised to CABG and 466 to MED. Change in 6 min walk distance between baseline and follow-up were compared by treatment allocation.
Results: 6 min walk distance at baseline for CABG was mean 340±117 m and for MED 339±118 m. Change in walk distance from baseline was similar for CABG and MED groups at 4 months (mean +38 vs +28 m), 12 months (+47 vs +36 m), 24 months (+31 vs +34 m) and 36 months (−7 vs +7 m), P>0.10 for all. Change in walk distance between CABG and MED groups over all assessments was also similar after adjusting for covariates and imputation for missing values (+8 m, 95% CI −7 to 23 m, P=0.29). Results were consistent for subgroups defined by angina, New York Heart Association class ≥3, left ventricular ejection fraction, baseline walk distance and geographic region.
Conclusion: In patients with ischaemic left ventricular dysfunction CABG compared with MED alone is known to reduce mortality but is unlikely to result in a clinically significant improvement in functional capacity
Impact of Regional Systems of Care on Disparities in Care Among Female and Black Patients Presenting With ST‐Segment–Elevation Myocardial Infarction
BACKGROUND: The American Heart Association Mission: Lifeline STEMI (ST-segment-elevation myocardial infarction) Systems Accelerator program, conducted in 16 regions across the United States to improve key care processes, resulted in more patients being treated within national guideline goals (time from first medical contact to device: <90 minutes for direct presenters to hospitals capable of performing percutaneous coronary intervention; <120 minutes for transfers). We examined whether the effort reduced reperfusion disparities in the proportions of female versus male and black versus white patients.
METHODS AND RESULTS: In total, 23 809 patients (29.3% female, 82.3% white, and 10.7% black) presented with acute STEMI between July 2012 and March 2014. Change in the proportion of patients treated within guideline goals was compared between sex and race subgroups for patients presenting directly to hospitals capable of performing percutaneous coronary intervention (n=18 267) and patients requiring transfer (n=5542). The intervention was associated with an increase in the proportion of men treated within guideline goals that presented directly (58.7-62.1%, P=0.01) or were transferred (43.3-50.7%, P<0.01). An increase was also seen among white patients who presented directly (57.7-59.9%, P=0.02) or were transferred (43.9-48.8%, P<0.01). There was no change in the proportion of female or black patients treated within guideline goals, including both those presenting directly and transferred.
CONCLUSION: The STEMI Systems Accelerator project was associated with an increase in the proportion of patients meeting guideline reperfusion targets for male and white patients but not for female or black patients. Efforts to organize systems of STEMI care should implement additional processes targeting barriers to timely reperfusion among female and black patients
Association of Rapid Care Process Implementation on Reperfusion Times Across Multiple ST-Segment–Elevation Myocardial Infarction Networks
BACKGROUND: The Mission: Lifeline STEMI Systems Accelerator program, implemented in 16 US metropolitan regions, resulted in more patients receiving timely reperfusion. We assessed whether implementing key care processes was associated with system performance improvement.
METHODS AND RESULTS: Hospitals (n=167 with 23 498 ST-segment-elevation myocardial infarction patients) were surveyed before (March 2012) and after (July 2014) program intervention. Data were merged with patient-level clinical data over the same period. For reperfusion, hospitals were grouped by whether a specific process of care was implemented, preexisting, or never implemented. Uptake of 4 key care processes increased after intervention: prehospital catheterization laboratory activation (62%-91%; P<0.001), single call transfer protocol from an outside facility (45%-70%; P<0.001), and emergency department bypass for emergency medical services direct presenters (48%-59%; P=0.002) and transfers (56%-79%; P=0.001). There were significant differences in median first medical contact-to-device times among groups implementing prehospital activation (88 minutes implementers versus 89 minutes preexisting versus 98 minutes nonimplementers; P<0.001 for comparisons). Similarly, patients treated at hospitals implementing single call transfer protocols had shorter median first medical contact-to-device times (112 versus 128 versus 152 minutes; P<0.001). Emergency department bypass was also associated with shorter median first medical contact-to-device times for emergency medical services direct presenters (84 versus 88 versus 94 minutes; P<0.001) and transfers (123 versus 127 versus 167 minutes; P<0.001).
CONCLUSIONS: The Accelerator program increased uptake of key care processes, which were associated with improved system performance. These findings support efforts to implement regional ST-segment-elevation myocardial infarction networks focused on prehospital catheterization laboratory activation, single call transfer protocols, and emergency department bypass
Regional Systems of Care Demonstration Project: American Heart Association Mission: Lifeline STEMI Systems Accelerator.
BACKGROUND: Up to 50% of patients fail to meet ST-segment-elevation myocardial infarction (STEMI) guideline goals recommending a first medical contact-to-device time of <90 minutes for patients directly presenting to percutaneous coronary intervention-capable hospitals and <120 minutes for transferred patients. We sought to increase the proportion of patients treated within guideline goals by organizing coordinated regional reperfusion plans.
METHODS: We established leadership teams, coordinated protocols, and provided regular feedback for 484 hospitals and 1253 emergency medical services (EMS) agencies in 16 regions across the United States.
RESULTS: Between July 2012 and December 2013, 23 809 patients presented with acute STEMI (direct to percutaneous coronary intervention hospital: 11 765 EMS transported and 6502 self-transported; 5542 transferred). EMS-transported patients differed from self-transported patients in symptom onset to first medical contact time (median, 47 versus 114 minutes), incidence of cardiac arrest (10% versus 3%), shock on admission (11% versus 3%), and in-hospital mortality (8% versus 3%; P<0.001 for all comparisons). There was a significant increase in the proportion of patients meeting guideline goals of first medical contact-to-device time, including those directly presenting via EMS (50% to 55%; P<0.001) and transferred patients (44%-48%; P=0.002). Despite regional variability, the greatest gains occurred among patients in the 5 most improved regions, increasing from 45% to 57% (direct EMS; P<0.001) and 38% to 50% (transfers; P<0.001).
CONCLUSIONS: This Mission: Lifeline STEMI Systems Accelerator demonstration project represents the largest national effort to organize regional STEMI care. By focusing on first medical contact-to-device time, coordinated treatment protocols, and regional data collection and reporting, we were able to increase significantly the proportion of patients treated within guideline goals
Quality of life impact and recovery after ureteroscopy and stent insertion: Insights from daily surveys in STENTS
BACKGROUND: Our objective was to describe day-to-day evolution and variations in patient-reported stent-associated symptoms (SAS) in the STudy to Enhance uNderstanding of sTent-associated Symptoms (STENTS), a prospective multicenter observational cohort study, using multiple instruments with conceptual overlap in various domains.
METHODS: In a nested cohort of the STENTS study, the initial 40 participants having unilateral ureteroscopy (URS) and stent placement underwent daily assessment of self-reported measures using the Brief Pain Inventory short form, Patient-Reported Outcome Measurement Information System measures for pain severity and pain interference, the Urinary Score of the Ureteral Stent Symptom Questionnaire, and Symptoms of Lower Urinary Tract Dysfunction Research Network Symptom Index. Pain intensity, pain interference, urinary symptoms, and bother were obtained preoperatively, daily until stent removal, and at postoperative day (POD) 30.
RESULTS: The median age was 44 years (IQR 29,58), and 53% were female. The size of the dominant stone was 7.5 mm (IQR 5,11), and 50% were located in the kidney. There was consistency among instruments assessing similar concepts. Pain intensity and urinary symptoms increased from baseline to POD 1 with apparent peaks in the first 2 days, remained elevated with stent in situ, and varied widely among individuals. Interference due to pain, and bother due to urinary symptoms, likewise demonstrated high individual variability.
CONCLUSIONS: This first study investigating daily SAS allows for a more in-depth look at the lived experience after URS and the impact on quality of life. Different instruments measuring pain intensity, pain interference, and urinary symptoms produced consistent assessments of patients\u27 experiences. The overall daily stability of pain and urinary symptoms after URS was also marked by high patient-level variation, suggesting an opportunity to identify characteristics associated with severe SAS after URS
Effect of a Hospital and Postdischarge Quality Improvement Intervention on Clinical Outcomes and Quality of Care for Patients With Heart Failure With Reduced Ejection Fraction: The CONNECT-HF Randomized Clinical Trial
Importance: Adoption of guideline-directed medical therapy for patients with heart failure is variable. Interventions to improve guideline-directed medical therapy have failed to consistently achieve target metrics, and limited data exist to inform efforts to improve heart failure quality of care.
Objective: To evaluate the effect of a hospital and postdischarge quality improvement intervention compared with usual care on heart failure outcomes and care.
Design, Setting, and Participants: This cluster randomized clinical trial was conducted at 161 US hospitals and included 5647 patients (2675 intervention vs 2972 usual care) followed up after a hospital discharge for acute heart failure with reduced ejection fraction (HFrEF). The trial was performed from 2017 to 2020, and the date of final follow-up was August 31, 2020.
Interventions: Hospitals (n = 82) randomized to a hospital and postdischarge quality improvement intervention received regular education of clinicians by a trained group of heart failure and quality improvement experts and audit and feedback on heart failure process measures (eg, use of guideline-directed medical therapy for HFrEF) and outcomes. Hospitals (n = 79) randomized to usual care received access to a generalized heart failure education website.
Main Outcomes and Measures: The coprimary outcomes were a composite of first heart failure rehospitalization or all-cause mortality and change in an opportunity-based composite score for heart failure quality (percentage of recommendations followed).
Results: Among 5647 patients (mean age, 63 years; 33% women; 38% Black; 87% chronic heart failure; 49% recent heart failure hospitalization), vital status was known for 5636 (99.8%). Heart failure rehospitalization or all-cause mortality occurred in 38.6% in the intervention group vs 39.2% in usual care (adjusted hazard ratio, 0.92 [95% CI, 0.81 to 1.05). The baseline quality-of-care score was 42.1% vs 45.5%, respectively, and the change from baseline to follow-up was 2.3% vs -1.0% (difference, 3.3% [95% CI, -0.8% to 7.3%]), with no significant difference between the 2 groups in the odds of achieving a higher composite quality score at last follow-up (adjusted odds ratio, 1.06 [95% CI, 0.93 to 1.21]).
Conclusions and Relevance: Among patients with HFrEF in hospitals randomized to a hospital and postdischarge quality improvement intervention vs usual care, there was no significant difference in time to first heart failure rehospitalization or death, or in change in a composite heart failure quality-of-care score.
Trial Registration: ClinicalTrials.gov Identifier: NCT03035474
Does prior coronary angioplasty affect outcomes of surgical coronary revascularization? Insights from the STICH trial
Background:
The STICH trial showed superiority of coronary artery bypass plus medical treatment (CABG) over medical treatment alone (MED) in patients with left ventricular ejection fraction (LVEF) ≤35%. In previous publications, percutaneous coronary intervention (PCI) prior to CABG was associated with worse prognosis.
Objectives:
The main purpose of this study was to analyse if prior PCI influenced outcomes in STICH.
Methods and results:
Patients in the STICH trial (n = 1212), followed for a median time of 9.8 years, were included in the present analyses. In the total population, 156 had a prior PCI (74 and 82, respectively, in the MED and CABG groups). In those with vs. without prior PCI, the adjusted hazard-ratios (aHRs) were 0.92 (95% CI = 0.74–1.15) for all-cause mortality, 0.85 (95% CI = 0.64–1.11) for CV mortality, and 1.43 (95% CI = 1.15–1.77) for CV hospitalization. In the group randomized to CABG without prior PCI, the aHRs were 0.82 (95% CI = 0.70–0.95) for all-cause mortality, 0.75 (95% CI = 0.62–0.90) for CV mortality and 0.67 (95% CI = 0.56–0.80) for CV hospitalization. In the group randomized to CABG with prior PCI, the aHRs were 0.76 (95% CI = 0.50–1.15) for all-cause mortality, 0.81 (95% CI = 0.49–1.36) for CV mortality and 0.61 (95% CI = 0.41–0.90) for CV hospitalization. There was no evidence of interaction between randomized treatment and prior PCI for any endpoint (all adjusted p > 0.05).
Conclusion:
In the STICH trial, prior PCI did not affect the outcomes of patients whether they were treated medically or surgically, and the superiority of CABG over MED remained unchanged regardless of prior PCI.
Clinical trial registration:
Clinicaltrials.gov; Identifier: NCT0002359
Autoimmune enteropathy with a CD8+ CD7- T-cell small bowel intraepithelial lymphocytosis: case report and literature review
<p>Abstract</p> <p>Background</p> <p>Adult onset autoimmune enteropathy (AIE) is a rare condition characterized by diarrhea refractory to dietary therapy diagnosed in patients with evidence of autoimmune conditions. Auto-antibodies to gut epithelial cells and other tissues are commonly demonstrated. Despite increasing awareness, the pathogenesis, histologic, immunologic and clinical features of AIE remain uncertain. There remains controversy regarding the diagnostic criteria, the frequency and types of auto-antibodies and associated autoimmune conditions, and the extent and types of histologic and immunologic abnormalities. CD4+ T-cells are thought to at least responsible for this condition; whether other cell types, including B- and other T-cell subsets are involved, are uncertain. We present a unique case of AIE associated with a CD8+CD7- lymphocytosis and review the literature to characterize the histologic and immunologic abnormalities, and the autoantibodies and autoimmune conditions associated with AIE.</p> <p>Case Presentation</p> <p>We present a case of immune mediated enteropathy distinguished by the CD8+CD7- intra-epithelial and lamina propria lymphocytosis. Twenty-nine cases of AIE have been reported. The majority of patients had auto-antibodies (typically anti-enterocyte), preferential small bowel involvement, and predominately CD3+ CD4+ infiltrates. Common therapies included steroids or immuno-suppressive agents and clinical response with associated with histologic improvement.</p> <p>Conclusions</p> <p>AIE is most often characterized (1) IgG subclass anti-epithelial cell antibodies, (2) preferential small bowel involvement, and (3) CD3+ alphabeta TCR+ infiltrates; there is insufficient evidence to conclude CD4+ T-cells are solely responsible in all cases of AIE.</p
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