830 research outputs found
Strategies for Supporting Student Learning Needs during the COVID Pandemic in Maine and Other States
Maine Educational Policy Research Institute (MEPRI) report based on a study of the strategies and challenges involved in supporting preK–12 students and teachers during the COVID-19 pandemic
LEC GaAs for integrated circuit applications
Recent developments in liquid encapsulated Czochralski techniques for the growth of semiinsulating GaAs for integrated circuit applications have resulted in significant improvements in the quality and quantity of GaAs material suitable for device processing. The emergence of high performance GaAs integrated circuit technologies has accelerated the demand for high quality, large diameter semiinsulating GaAs substrates. The new device technologies, including digital integrated circuits, monolithic microwave integrated circuits and charge coupled devices have largely adopted direct ion implantation for the formation of doped layers. Ion implantation lends itself to good uniformity and reproducibility, high yield and low cost; however, this technique also places stringent demands on the quality of the semiinsulating GaAs substrates. Although significant progress was made in developing a viable planar ion implantation technology, the variability and poor quality of GaAs substrates have hindered progress in process development
Strategies for Supporting Teachers’ Instructional and Mental Health Needs during the COVID Pandemic in Maine and Other States
The Maine Educational Policy Research Institute (MEPRI) report based on a study of the strategies and challenges involved in supporting preK–12 students and teachers during the COVID-19 pandemic
Update on the Talent aortic stent-graft: A preliminary report from United States phase I and II trials
AbstractPurpose: Phase I and phase II trials were conducted to determine the safety and efficacy of the Talent aortic stent-graft (Medtronic World Medical, Sunrise, Fla) in the treatment of infrarenal abdominal aortic aneurysms (AAA). This is a preliminary report of the technical results and 30-day clinical outcome of these trials. Methods: Multicenter prospective trials were conducted to test the Talent stent-graft in high-risk and low-risk patient populations with AAA, including phase I feasibility and phase II clinical trials. The low-risk study included concurrent surgical controls. Results: In the phase I trial, deployment success was achieved in 92% (23/25 patients), and initial technical success was 78% (18/23 implants without endoleak). The 30-day technical success rate was 96%, with six endoleaks that resolved spontaneously (without need for further intervention); and the 30-day mortality rate was 12% (3/25 patients). The phase II high-risk trial demonstrated a deployment success of 94% (119/127 patients) and an initial technical success of 86% (102/119 implants). The 30-day technical success rate was 96%, and the 30-day mortality rate was 1.5% (2/127 patients). The phase II low-risk trial included a first-generation and a second-generation Talent stent-graft. Deployment success rates were 97% and 99%, respectively, and technical success rates at 30 days were 97% and 96%, respectively. The 30-day mortality rate was 2% in the phase II low-risk first-generation device trial, and the adverse-event rate was 20%. Corresponding figures for the second-generation device were 0% and 1.8%, respectively. Conclusion: The Talent stent-graft can be deployed successfully and achieves endovascular exclusion in a large proportion of patients with AAA. Morbidity and mortality rates are acceptable. One-year clinical results and the comparison with concurrent surgical control subjects remain to be evaluated. (J Vasc Surg 2001;33:S146-9.
Predictors of early and late mortality following open extent IV thoracoabdominal aortic aneurysm repair in a large contemporary single-center experience
ObjectiveThe primary purpose of this study was to examine outcomes following open repair of extent IV thoracoabdominal aortic aneurysms (TAAAs) at a single university hospital. As a secondary aim, comparison was made to patients who underwent open abdominal aortic aneurysm (AAA) repair with supraceliac clamping but without left renal artery bypass to assess the effect of left renal artery bypass on outcomes.MethodsPatients undergoing open extent IV TAAA repair from 1998 to 2008 were identified (n = 108). Primary outcomes were 30-day and long-term survival. Secondary outcomes were major complication, renal failure, and postoperative change in renal function. A second analysis was performed, comparing patients undergoing extent IV TAAA repair with patients undergoing AAA repair with supraceliac clamping but without left renal artery bypass (n = 50).ResultsEighty-three men (76.9%) and 25 women (23.1%), with a mean age of 72.9 years, underwent open extent IV TAAA repair. Nine patients (8.3%) were ruptured. Mean aneurysm maximal diameter was 6.5 ± 1.3 cm. Supraceliac and left renal ischemic times were 22.9 ± 9.3 and 40.6 ± 16.2 minutes, respectively. Six patients (5.6%) died at 30 days. The only predictor of 30-day mortality was decreased preoperative estimated glomerular filtration rate (eGFR) (P = .044 by multivariate analysis; and P = .011 by univariate analysis). One-year and 5-year survival rates were 87% and 50%, respectively. Patients with a history of cerebrovascular disease (P = .001) and postoperative renal insufficiency (P = .034) had increased long-term mortality by log-rank test. Twenty-five (25.3%) patients sustained a postoperative decrease in renal function, while 19 (19.2%) patients had an improvement in renal function. There was no difference in 30-day mortality (5.6% vs 6.0%; P = 1.000), 5-year survival (50% vs 48%; P = .886), major complications (37.0% vs 38.0%; P = 1.000), renal failure (6.1% vs 0%; P = .215), or postoperative change in renal function, in patients undergoing extent IV TAAA repair vs AAA repair with supraceliac clamping but without left renal artery bypass.ConclusionsOpen extent IV TAAA repair can be performed with low morbidity and mortality rates. The performance of left renal artery bypass does not appear to contribute to the morbidity and mortality of extent IV TAAA repair. While decreased preoperative eGFR appears to increase the risk of 30-day mortality, a history of cerebrovascular disease and postoperative renal insufficiency appear to increase the risk of long-term mortality. Finally, open extent IV TAAA repair not uncommonly improves renal function
Propensity-matched cohort validates findings of the VALOR trial
IntroductionThe Evaluation of the Medtronic Vascular Talent Thoracic Stent Graft System for the Treatment of Thoracic Aortic Aneurysms (VALOR) trial findings noted superior 30-day and 1-year outcomes of the Talent thoracic endograft (Medtronic Vascular, Santa Rosa, Calif) compared with surgical repair of descending thoracic aneurysms (DTAs). Data from 195 prospective thoracic endovascular aneurysm repair (TEVAR) patients treated with the Talent device and 189 retrospective controls undergoing open surgical repair (OSR) from three centers of excellence were included in the trial after completion of TEVAR enrollment and compared. Such comparisons are biased by baseline differences among TEVAR vs OSR, however, propensity score (PS) analysis can reduce bias and validate such comparisons.MethodsLogistic regression was used to generate a PS (range, 0-1) to identify baseline characteristics more likely in TEVAR. The PS estimated the probability that any patient would undergo TEVAR (eg, a PS of 0.99 represents a 99% chance a patient belongs to TEVAR). PSs were then generated for all patients, and TEVAR and OSR patients were divided into tertiles based on the PS to reduce up to 80% of inherent bias. Outcomes from the middle tertile (T2), patients equally likely (midrange PS) to be in TEVAR or OSR and therefore best matched, were compared using regression analysis and were also compared with the outcomes in the overall trial group.ResultsCorrelates of membership in TEVAR were smaller aneurysm (P < .001), anticoagulants (P < .01), no previous abdominal aortic aneurysm (AAA) repair (P < .01), no peripheral vascular disease (P = .001), statin use (P = .002), aspirin use (P = .002), older age (P = .028), race (P = .007), male gender (P = .02), and heart failure (P = .035). T2 included 68 TEVAR (PS, 0.58 ± 0.2) and 67 OSR patients (PS, 0.46 ± 0.2). VALOR overall reported differences in aneurysm size (56 mm TEVAR vs 69 mm open) and prior AAA repair (19% TEVAR vs 37% open), and this adjusted to no differences in T2 patients. In the well-matched T2 cohort, TEVAR patients had similar 30-day mortality (0% vs 3% OSR; P = .2) and improved 1-year aneurysm-related mortality rates (0% TEVAR vs 8% OSR; P = .05) compared with the OSR patients. This finding was in concurrence with the VALOR trial reporting similar benefit in TEVAR patients. The all-cause 1-year mortality showed a favorable trend for TEVAR in the VALOR trial; however, in T2 patients, 1-year all-cause mortality was similar in both groups of patients (17% TEVAR vs 15% OSR; P = .8). Age (P = .01), history of cerebrovascular accident (P < .05), antiarrhythmia medication (P = .04), and renal disease (P < .03) independently predicted all-cause and aneurysm-related mortality by regression analysis.ConclusionsPS analysis is an important tool for elimination of bias inherent when retrospective controls are used. Its application to VALOR validates the long-term benefit in aneurysm-related mortality conferred by TEVAR in patients undergoing endovascular DTA repair
The RNA helicase database
RNA helicases are ubiquitous and essential enzymes that function in nearly all aspects of RNA metabolism. The RNA helicase database (www.rnahelicase.org) integrates the wealth of accumulating information on RNA helicases in a readily accessible format. The database is a portal that allows straightforward retrieval of comprehensive information on sequence, structure and on biochemical and cellular functions of all RNA helicases from the most widely used model organisms Escherichia coli, Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, mouse and human. Also included are RNA helicases from other organisms that are subject to specific investigation. The database is structured according to the most recent helicase classification into helicase superfamilies (SFs) and families, and thus emphasizes phyologenetic relations between RNA helicases as well. Information on individual RNA helicases can be accessed through various browsing routes or through text-based searches of the database
Iterative Design and Usability Testing of the iMHere System for Managing Chronic Conditions and Disability
A novel mobile health platform, Interactive Mobile Health and Rehabilitation (iMHere), is being developed to support wellness and self-management among people with chronic disabilities. The iMHere system currently includes a smartphone app with six modules for use by persons with disabilities and a web portal for use by medical and rehabilitation professionals or other support personnel. Our initial clinical research applying use of this system provides insight into the feasibility of employing iMHere in the development of self-management skills in young adults (ages 18-40 years) with spina bifida (Dicianno, Fairman, McCue, Parmanto, Yih, et al., 2015). This article is focused on describing the iterative design of the iMHere system including usability testing of both the app modules and clinician portal. Our pilot population of persons with spina bifida fostered the creation of a system appropriate for people with a wide variety of functional abilities and needs. As a result, the system is appropriate for use by persons with various disabilities and chronic conditions, not only spina bifida. In addition, the diversity of professionals and support personnel involved in the care of persons with spina bifida (SB) also enabled the design and implementation of the iMHere system to meet the needs of an interdisciplinary team of providers who treat various conditions. The iMHere system has the potential to foster communication and collaboration among members of an interdisciplinary healthcare team, including individuals with chronic conditions and disabilities, for client-centered approach to support self-management skills.
Limb interventions in patients undergoing treatment with an unsupported bifurcated aortic endograft system: A review of the Phase II EVT Trial
AbstractIntroduction: Both supported and unsupported bifurcated endograft limbs develop flow-restricting lesions, including kinks, stenoses, and occlusions, which can be identified during or after surgery. Recognition and intervention are essential to achieve long-term graft patency and a satisfactory functional result. This report represents a comprehensive retrospective review of graft limb interventions from the Phase II EVT Trial with the Endovascular Grafting System unsupported bifurcated endograft (Guidant/EVT, Menlo Park, Calif). Methods: The study population consists of 242 patients who underwent treatment with bifurcated endografts implanted during the EVT Phase II Trial. Graft limb interventions have been divided into two groups: those in whom the intervention occurred during surgery versus those in whom the intervention occurred after surgery. Parameters studied included type, incidence, and timing of graft limb intervention, indications for intervention, procedures performed, and overall patient outcome. Results: The mean follow-up period was 31 months. Primary, primary assisted, and secondary limb patency rates were 61.6%, 93.7%, and 97.1%, respectively. Technical success rate at case completion was 97.5%. In 68 of the 242 cases, limb interventions were performed during surgery to assure patency (28.1%). In 28 cases, interventions were performed after surgery (11.6%). Of these postoperative limb problems, 82% occurred during the first 6 months. Repeat limb interventions were necessitated in three patients (1.2%). Within the intraoperative intervention group, perceived indications included kinks (15%), stenosis (57%), dissection (6%), graft redundancy (12%), and instances of twists, thrombosis, and pressure gradients (10%). These findings were successfully managed with percutaneous transluminal angioplasty only (41%), percutaneous transluminal angioplasty and stent (50%), and various combined interventions. Within the postoperative intervention group, symptomatic indications included stenosis (46%) and thrombosis/occlusion (54%). These postoperative limb events were successfully managed with stent (64%), thrombolysis (32%), and femoral-femoral bypass (21%). When limb dysfunction developed in the postoperative setting, it most often occurred within the first 6 months of implantation. Only one patient in this Phase II cohort had a lower extremity amputation unrelated to a graft limb abnormality. Conclusion: The unsupported bifurcated limbs of this endograft necessitated primary adjunctive intervention in 40% of cases. Primary intervention was two times more likely to be performed at the time of the implant rather than after surgery. Repeat limb interventions were not common. Endograft limb flow problems were successfully treated with standard endovascular or surgical interventions or both. These data may support prophylactic stenting of unsupported Ancure graft limbs. A strategy that includes both intraoperative and early postoperative graft limb surveillance is essential to detect reduced limb flow. (J Vasc Surg 2002;36:118-26.
PS64. A Comparison of Carotid Endarterectomy and Carotid Artery Stenting in Patients Undergoing Cardiac Surgery
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