21 research outputs found

    KSC Facilities Status and Planned Management Operations

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    This is a status report on the facilities and planned operations at the Kennedy Space Center that will support Space Shuttle launches, the first of which is now scheduled for late 1979. The facilities are essentially complete, with all new construction and modifications to existing buildings almost finished. Some activity is still in progress at Pad A and on the Mobile Launcher, due to changes in requirements, but is not expected to impact the launch schedule. The installation and testing of the ground checkout equipment that will be used to test the fIight hardware is now in work. The Launch Processing System is currently supporting the development of the applications software that will perform the testing of this fIight hardware. The Shuttle Program is unique to past manned space programs in that very tight budgetary constraints have been imposed in an effort to keep the costs low. For KSC, this means adopting a philosophy of launch-to-cost. In an era of routine space flight, this presents a very real challenge to management; the necessity of controlling costs while maintaining tight schedules. An overview of how this management challenge is to be met will be presented

    Cardiac interventions in patients with achondroplasia: a systematic review.

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    Patients with achondroplasia and other causes of dwarfism suffer from increased rates of cardiovascular disease relative to the remainder of the population. Few studies have examined these patients when undergoing cardiac surgery or percutaneous intervention. This systematic review examines the literature to determine outcomes following cardiac intervention in this unique population. An electronic search was performed in the English literature to identify all reports of achondroplasia, dwarfism, and cardiac intervention. Of the 5,274 articles identified, 14 articles with 14 cases met inclusion criteria. Patient-level data was extracted and analyzed. Median patient age was 55.5 [interquartile ranges (IQR), 43.8, 59.8] years, median height 102.0 [98.8, 112.5] cm, median BMI 32.1 [27.0, 45.9], and 57.1% (8/14) were male. Of these 14 patients, nine had the following documented skeletal abnormalities: 66.7% (6/9) had scoliosis, 66.7% (6/9) had kyphosis, 11.1% (1/9) had lordosis, 11.1% (1/9) pectus carinatum and 11.1% (1/9) spinal stenosis. Coronary artery disease was present in 53.8% (7/13), and 30.8% (4/13) patients previously suffered a myocardial infarction. Of the eight patients who underwent cardiac surgery, 37.5% (3/8) underwent multivessel coronary artery bypass grafting, 37.5% (3/8) underwent aortic valve replacement, 25.0% (2/8) underwent type A aortic dissection repair, and the remaining 12.5% (1/8) underwent pulmonary thromboendarterectomy. Six patients underwent percutaneous intervention. Median cardiopulmonary bypass time was 136.5 [110.0, 178.8] minutes. Median arterial cannula size was 20.0 [20.0, 24.0] Fr. Bicaval cannulation was performed in all cases describing cannulation strategy (5/5). Median superior vena cava cannula size was 28.0 [28.0, 28.0] Fr, and inferior vena cava cannula size was 28.0 [28.0, 28.0] Fr. No mortality was reported with a median follow up time of 6.0 [6.0, 10.5] months. In conclusion, Common cardiac procedures can be performed with reasonable safety in this patient population. Operative adjustments may need to be made with respect to equipment to accommodate patient-specific needs

    Continuous-flow left ventricular assist device outflow graft stenting: Indications and outcomes

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    Introduction: Stenosis in the continuous-flow left ventricular assist device (CF-LVAD) outflow graft can be caused by various mechanical and anatomical factors. Increasingly, percutaneous management has been utilized to re-establish adequate CF-LVAD flow. We sought to evaluate indications for such interventions and their outcomes. Methods: An electronic search was performed to identify all studies in the English literature reporting CF-LVAD outflow graft stenting for various etiologies. Twenty-one studies consisting of 26 patients were included in the analysis. Results: Median patient age was 59 years [45.8-67.0] and 65.4% (17/26) were male. 58.3% (14/24) of patients had HeartWare HVAD, 37.5% (9/24) had HeartMate II LVAD, and 4.2% (1/24) had HeartMate III LVAS. Median time from device placement to outflow graft stenting was 24.0 months [7.8-30.4]. 76.9% of patients (20/26) presented with heart failure. 34.6% (9/26) had outflow graft thrombosis, 34.6% (9/26) stenosis, 11.5% (3/26) kinking, 11.5% (3/26) pseudoaneurysm, 3.8% (1/26) external graft compression, and 3.8% (1/26) had a bronchialarterial fistula. 88.5% (23/26) procedures led to immediate flow improvement with the remaining 11.5% (3/26) receiving additional stenting. Post-intervention flows were significantly improved (4.7 L/min [4.1-4.8] post-intervention vs 2.9 L/min [2.0-3.5] initial, p=0.01). 96.2% (25/26) patients were discharged from the hospital. The 30-day mortality was 6.7% (1/15). Overall mortality during the median follow-up of 90 days [7.0-240.0] was 9.5% (2/21). Discussion: Outflow graft stenting appears to effectively alleviate CF-LVAD outflow graft obstruction with low mortality. Longer-term follow up is necessary to determine the longevity of such an intervention but early results are promising

    Bronchial artery revascularization in lung transplantation: a systematic review and meta-analysis.

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    Background: Bronchial artery revascularization (BAR) during lung transplantation has been hypothesized to improve early tracheal healing and delay the onset of bronchiolitis obliterans syndrome (BOS). We aimed to assess the outcomes of BAR after lung transplantation. Methods: Electronic search in Ovid Medline, Cumulative Index of Nursing and Allied Health Literature (CINAHL), Scopus, and Cochrane Controlled Trials Register (CCTR) databases was performed to identify all relevant studies published about lung transplantation with BAR. Studies discussing lung transplantation utilizing BAR were included while those without outcome data such as BOS and survival were excluded. Cohort-level data were extracted and pooled for analysis. A binary outcome meta-analysis of proportions with logit transformation was conducted. Newcastle-Ottawa scale was used for risk of bias assessment. Results: Seven studies were selected for the analysis comprising 143 patients. Mean patient age was 47 (95% CI: 40-55) years. Sixty-one percent (48-72%) were male. Seventy-three percent (65-79%) of patients underwent double lung transplant while 27% (21-25%) underwent single lung transplant. In patients with postoperative angiography, successful BAR was demonstrated in 93% (82-97%) of all assessed conduits. The 30-day/in-hospital mortality was 6% (3-11%). Seventy-nine percent (63-89%) of patients were free from rejection at three months. Eighty-three percent (29-98%) of patients were free from signs of airway ischemia at three and six months. Pooled survival at one year and five years was 87% (78-92%) and 71% (46-87%), respectively, with a mean follow-up time of 21 (3-38) months. Pooled freedom from bronchiolitis obliterans was 86% (77-91%) at two years. Conclusions: While this systematic review and meta-analysis is limited by the available surgeons, institutions, and papers discussing a highly specialized technique, it does show that BAR is a viable technique to minimize BOS and early anastomotic intervention following lung transplantation

    Surgical Pulmonary Embolectomy Outcomes for Acute Pulmonary Embolism

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    Introduction: Acute pulmonary embolism (PE) is associated with significant mortality. Surgical embolectomy is a viable treatment option; however, it remains controversial due to variable outcomes. This review investigates patient outcomes following surgical embolectomy for acute PE. Methods: Electronic search was performed to identify articles reporting surgical embolectomy for treatment of PE. 32 studies were included comprising 936 patients. Demographic, perioperative, and outcome data were extracted and pooled for systematic review. Results: Mean patient age was 56.3 [95% CI 52.5; 60.1] years and 50% [46; 55] were male. 82% had right ventricular dysfunction [62; 93], 80% [67; 89] had unstable hemodynamics, and 9% [5; 16] experienced cardiac arrest. Massive PE and submassive PE were present in 83% of patients [43; 97] and 13% [2; 56], respectively. Before embolectomy, 33% of patients [14; 60] underwent systemic thrombolysis and 14% [8; 24] catheter embolectomy. Preoperatively, 47% of patients were ventilated [26; 70] and 36% had percutaneous cardiopulmonary support [11; 71]. Mean operative time and mean cardiopulmonary bypass time were 170 [101; 239] and 56 [42; 70] minutes, respectively. Intraoperative mortality was 4% [2; 8]. Mean hospital and ICU stay were 10 [6; 14] and 2 [1; 3] days, respectively. Mean postoperative systolic pulmonary artery pressure (sPAP) was significantly decreased from preoperative (sPAP 57.8 mmHg [53; 62.7]) to postoperative period (sPAP 31.3 mmHg [24.9; 37.8]), p \u3c0.01). In-hospital mortality was 16% [12; 21]. Overall survival at five years was 73% [64; 81]. Discussion: Surgical embolectomy is an acceptable treatment option with favorable outcomes

    Endovascular Intervention for Tracheo-Innominate Fistula: A Systematic Review and Meta-analysis

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    Introduction: Fistula formation between the trachea and the innominate artery is a life-threatening complication rarely seen with existing or previous tracheostomy. Fatal upon rupture, swift diagnosis and immediate intervention are paramount for survival. We aim to identify feasibility and outcomes of endovascular intervention for trachea-innominate fistula (TIF). Methods: Patient-level data of reported individuals above the age of 14 that underwent endovascular intervention for TIF was extracted and analyzed. Identification of 25 patients from 27 studies was accomplished by electronic database search of Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, Ovid Medline, and Scopus. Survival data was evaluated by Kaplan-Meier analysis. Results: Median patient age was 39.0 years [IQR 16.0, 47.5]. Median time to TIF presentation following tracheostomy was 2.2 months [0.5, 42.5]. 84.6% (22/27) exhibited tracheal hemorrhage at presentation. Covered stent graft placement was performed in 96.3% (26/27) and coil embolization in 3.8% (1/27). Repeat endovascular intervention was necessary in 18.5% (5/27) and rescue sternotomy was required in 11.1% (3/27). Overall mortality was 29.6% (8/27) with a median follow-up time of 5 months [1.2, 11.5]. Discussion: Endovascular intervention may be an effective method of TIF repair at presentation. As an alternative to conventional surgical repair, endovascular intervention may be an appropriate method for TIF repair particularly in patients unfit for open sternotomy repair

    Outcomes of Surgical Treatment for Carcinoid Heart Disease: A Systematic Review and Meta-Analysis

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    Introduction and Objective: Carcinoid Heart Disease (CaHD) develops from vasoactive substances released by neuroendocrine tumors causing significant patient morbidity and mortality necessitating surgical intervention. We performed a systematic review and meta-analysis to elucidate granular perioperative details and long-term outcomes in these patients. Methods: Electronic search of Ovid, Scopus, Cumulative Index of Nursing and Allied Health Literature, and Cochrane Controlled Trials Register was performed. Nine articles comprising 416 patients who received surgery were selected. Primary outcomes investigated included patient characteristics, surgical characteristics and survival data. Study-level data were extracted and pooled for meta-analysis. Results: Primary outcomes consisted of survival, length of stay and thirty-day mortality. Secondary outcomes included presence of right heart failure pre-operatively and type of valve replaced. Right heart failure was present in 48%. Moderate or severe regurgitation was present in 97% of tricuspid and 72% of pulmonary valves. 99% of tricuspid and 59% of pulmonary valves were replaced. Mean hospital length of stay was 16 days. Thirty-day mortality was 9%. Mean follow up was 25 months. Median survival was 3 years. Conclusion: Surgical treatment of CaHD can be performed with acceptable short-term outcomes. However, overall survival appears to suffer from ongoing effects of the primary disease. Surgery is often performed after patients have extensive right-sided heart involvement. Overall, onset and duration of symptoms of carcinoid heart disease should be closely monitored to properly identify and refer patients who would most benefit from valvular surgery

    Calibration of Thermal Models of Steel Continuous Casting Molds

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    A new methodology is presented to calibrate the 1D CON1D model with a full 3D finite- element model of the mold. Coupled with models of solidification and interfacial phenomena, this modeling tool is applied to gain insights into many aspects of heat transfer in the process. The CON1D model is based on a 1D finite-difference solidification model of the shell, taking advantage of the large PĂ©clet number that makes axial heat conduction negligible relative to heat transported by the moving steel. It includes conduction and radiation across the interfacial layers, aided by mass, momentum and force balances on the slag, which are all solved analytically. Simplifying the mold geometry for the 1D model requires careful definition of the dimensions in order to retain the thermal characteristics of the system. This calibration of the thermocouple location should be performed after the water channel geometry has been calibrated

    The Magnetic and Electronic Structural Properties of the S3 State of Nature’s Water Oxidising Complex: A Combined Study in ELDOR-Detected Nuclear Magnetic Resonance Spectral Simulation and Broken Symmetry Density Functional Theory

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    ELDOR-detected Nuclear Magnetic Resonance (EDNMR) spectral simulations combined with broken symmetry density functional theory (BS-DFT) calculations are used to obtain and to assign the 55Mn hyperfine coupling constants (hfcs) for modified forms of the water oxidising complex in the penultimate S3 state of the water oxidation cycle. The study shows that an open cubane form of the core Mn4CaO6 cluster is the dominant S = 3 species in all cases studied experimentally with no need to invoke a closed cubane intermediate possessing a distorted pentacoordinate Mn4 ion. EDNMR simulations found that both the experimental bandwidth and multi-nuclear transitions may alter relative EDNMR peak intensities, potentially leading to incorrect assignment of hfcs. The implications of these findings for the water oxidation mechanism are discussed

    Calibration of Thermal Models of Continuous Casting of Steel

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    The harsh environment of commercial steel continuous casting processes makes taking measurements difficult, expensive and limited with regard to the information gained. Computational models potentially offer deeper knowledge, but only if they can accurately predict the plant behavior. This requires including and solving the equations which govern all of the important physical phenomena. To achieve reasonable speed while retaining accuracy, computational models must be simplified and calibrated to match plant experiments, using parameters which remain constant over the range of processing conditions of interest. Only after verification, calibration and validation can a model be used reliably as a predictive tool to investigative complex processes such as continuous casting
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