Reallocation of beds to reduce waiting time for cardiac surgery

Waiting time for cardiac surgery is a significant problem in the current medical world. The fact that patients length of stay varies considerably makes effective hospital operation a hard job. In this paper, the patients length of stay is analyzed. Three scenarios for hospital management are presented and evaluated in two ways. First, the theoretical number of beds needed in each of these scenarios is analyzed using techniques from Markov chain theory. This analysis does not include the important variability in length of stay. Therefore, the second evaluation is based on simulation experiments to further investigate the variability. The aim of the analyses is to look at unused bed capacity in the hospital wards. By knowing the size of the unused bed capacity, it is possible to come to a more efficient reallocation of the beds. The results presented in this paper provide some insight in the relation between patients length of stay, bed availability and hospital waiting lists. Finally, some ideas are raised as discussion points for further research.

Analysis of an advanced technology subsonic turbofan incorporating revolutionary materials

Successful implementation of revolutionary composite materials in an advanced turbofan offers the possibility of further improvements in engine performance and thrust-to-weight ratio relative to current metallic materials. The present analysis determines the approximate engine cycle and configuration for an early 21st century subsonic turbofan incorporating all composite materials. The advanced engine is evaluated relative to a current technology baseline engine in terms of its potential fuel savings for an intercontinental quadjet having a design range of 5500 nmi and a payload of 500 passengers. The resultant near optimum, uncooled, two-spool, advanced engine has an overall pressure ratio of 87, a bypass ratio of 18, a geared fan, and a turbine rotor inlet temperature of 3085 R. Improvements result in a 33-percent fuel saving for the specified misssion. Various advanced composite materials are used throughout the engine. For example, advanced polymer composite materials are used for the fan and the low pressure compressor (LPC)

Technology and benefits of aircraft counter rotation propellers

Results are reported of a NASA sponsored analytical investigation into the merits of advanced counter rotation propellers for Mach 0.80 commercial transport application. Propeller and gearbox performance, acoustics, vibration characteristics, weight, cost and maintenance requirements for a variety of design parameters and special features were considered. Fuel savings in the neighborhood of 8 percent relative to single rotation configurations are feasible through swirl recovery and lighter gearboxes. This is the net gain which includes a 5 percent acoustic treatment weight penalty to offset the broader frequency spectrum noise produced by counter rotation blading

Preliminary study of advanced turboprop and turboshaft engines for light aircraft

The effects of engine configuration, advanced component technology, compressor pressure ratio and turbine rotor-inlet temperature on such figures of merit as vehicle gross weight, mission fuel, aircraft acquisition cost, operating, cost and life cycle cost are determined for three fixed- and two rotary-wing aircraft. Compared with a current production turboprop, an advanced technology (1988) engine results in a 23 percent decrease in specific fuel consumption. Depending on the figure of merit and the mission, turbine engine cost reductions required to achieve aircraft cost parity with a current spark ignition reciprocating (SIR) engine vary from 0 to 60 percent and from 6 to 74 percent with a hypothetical advanced SIR engine. Compared with a hypothetical turboshaft using currently available technology (1978), an advanced technology (1988) engine installed in a light twin-engine helicopter results in a 16 percent reduction in mission fuel and about 11 percent in most of the other figures of merit

Advanced core technology: Key to subsonic propulsion benefits

A study was conducted to identify the potential performance benefits and key technology drivers associated with advanced cores for subsonic high bypass turbofan engines. Investigated first were the individual sensitivities of varying compressor efficiency, pressure ratio and bleed (turbine cooling); combustor pressure recovery; and turbine efficiency and inlet temperature on thermal efficiency and core specific power output. Then, engine cycle and mission performance benefits were determined for systems incorporating all potentially achievable technology advancements. The individual thermodynamic sensitivities are shown over a range of turbine temperatures (at cruise) from 2900 to 3500 R and for both constant (current technology) and optimum (maximum thermal efficiency) overall pressure ratios. It is seen that no single parameter alone will provide a large increase in core thermal efficiency, which is the thermodynamic parameter of most concern for transport propulsion. However, when all potentially achievable advancements are considered, there occurs a synergism that produces significant cycle and mission performance benefits. The nature of these benefits are presented along with the technology challenges

Reclassification of asymptomatic beta cell autoimmunity : a critical perspective

Type 1 diabetes is an immune-mediated disease leading to almost total beta cell destruction and permanent exogenous insulin dependency. The appearance of clinical symptoms is preceded by an asymptomatic preclinical period, the duration of which is highly individual. The emergence of diabetes-associated autoantibodies into the peripheral circulation is the first detectable sign of beta cell autoimmunity. If type 1 diabetes is diagnosed in childhood the preclinical period lasts for an average of 2.5-3 years, but clinical symptoms may in some cases appear within a few months or be delayed for more than 20 years. In this issue of Diabetologia, Bonifacio and colleagues (doi:) suggest that asymptomatic beta cell autoimmunity should be considered as a pathological and diagnostic entity. Although such a strategy may have some positive consequences, it might also have serious drawbacks. To label an asymptomatic child that may have 10-20 years of a healthy life ahead of him/her as a patient will most likely affect both the life of the family and the child. Therefore, we think that one should not adapt the new diagnosis before the psychological consequences of such a strategy have been assessed. Instead, since metabolic abnormalities precede the appearance of clinical symptoms of type 1 diabetes, analysis of a combination of immunological and metabolic markers will provide better insight into the likelihood of progression to clinical disease, with a shorter 'sickness' period.Peer reviewe

Lipidomics of human umbilical cord serum : identification of unique sterol sulfates

Aim: There are currently limited lipidomics data for human umbilical cord blood. Therefore, the lipidomes of cord sera from six newborns and sera from six nonpregnant females were compared. Materials & methods: Sera lipidomics analyses were conducted using a high-resolution mass spectrometry analytical platform. Results: Cord serum contained a diverse array of glycerophospholipids, albeit generally at lower concentrations than monitored in adult serum. The unexpected observations were that cord serum contained several neurosteroid sulfates and bile acid sulfates that were not detectable in adult serum. Conclusion: Our data are the first to demonstrate that cord serum contains bile acid sulfates that are synthesized early in the hydroxylase, neutral and acidic pathways of primary bile acid biosynthesis and support previous publications of cord blood perfluoralkyl toxins in newborns. Lay abstract: Umbilical cord blood offers the potential to increase our understanding of fetal development during pregnancy and during development after delivery. Our studies of complex sterols in umbilical cord blood (bile acid sulfates) suggest that with further studies these may be useful biomarkers of abnormal fetal liver development.Peer reviewe

Continuous glucose monitoring and HbA1c in the evaluation of glucose metabolism in children at high risk for type 1 diabetes mellitus

Aims: Continuous glucose monitoring (CGM) parameters, self-monitored blood glucose (SMBG), HbA1c and oral glucose tolerance test (OGTT) were studied during preclinical type 1 diabetes mellitus. Methods: Ten asymptomatic children with multiple (>= 2) islet autoantibodies (cases) and 10 age and sex-matched autoantibody-negative controls from the Type 1 Diabetes Prediction and Prevention (DIPP) Study were invited to 7-day CGM with Dexcom G4 Platinum Sensor. HbA1c and two daily SMBG values (morning and evening) were analyzed. Five-point OGTTs were performed and carbohydrate intake was assessed by food records. The matched pairs were compared with the paired sample t-test. Results: The cases showed higher mean values and higher variation in glucose levels during CGM compared to the controls. The time spent >= 7.8 mmol/l was 5.8% in the cases compared to 0.4% in the controls (p = 0.040). Postprandial CGM values were similar except after the dinner (6.6 mmol/l in cases vs. 6.1 mmol/l in controls; p = 0.023). When analyzing the SMBG values higher mean level, higher evening levels, as well as higher variation were observed in the cases when compared to the controls. HbA1c was significantly higher in the cases [5.7% (39 mmol/mol) vs. 5.3% (34 mmol/mol); p = 0.045]. No differences were observed in glucose or C-peptide levels during OGTT. Daily carbohydrate intake was slightly higher in the cases (254.2 g vs. 217.7 g; p = 0.034). Conclusions: Glucose levels measured by CGM and SMBG are useful indicators of dysglycemia during preclinical type 1 diabetes mellitus. Increased evening glucose values seem to be common in children with preclinical type 1 diabetes mellitus. (C) 2016 Elsevier Ireland Ltd. All rights reserved.Peer reviewe

Thermodynamic Cycle Analysis for Wave Rotor Combustor Based Combined Cycle

poster abstractThe conventional combustor that exists in today’s market is a constant pressure device; whereas, the wave rotor combustor investigated in the present research is a constant volume pressure gain device. This pressure gain wave rotor combustor improves the engine efficiency and reduces fuel consumption, engine weight and emissions. The objective of the present study is to observe and analyze the potential benefits of pressure gain combustion. Therefore, thermodynamic analysis has been conducted to evaluate the performance by comparing the simple Brayton constant pressure combustor with the wave rotor constant volume combustor, recuperated engines with unrecuperated engines, the pressure gain combustor with the work producing combustor, and the single stage Brayton cycle to the combined cycle for power generation applications. Thermodynamic analysis has been carried out by developing in-house code using engineering equation solver (EES) software to determine the overall specific fuel consumption, specific work, and efficiency of the constant volume combustion based cycles. A series of experiments have been conducted in the wave rotor combustor rig available at Combustion and Propulsion Research Laboratory, IUPUI. A high speed camera and pressure transducers have been employed to capture the jet ignition characteristics and to measure the pressure fluctuations during the combustion process respectively. Edge detection analysis is being conducted in MATLAB to determine the ignitability and ignition delay time in the combustion chamber. The measured pressure data are analyzed by EES software, using thermo- and gas dynamics theory, which performs exact analysis as opposed to limited previous studies using approximate analysis. This is expected to more accurately quantify the established results that replacing constant pressure with constant volume combustion increases the turbine cycle fuel efficiency. This work should encourage quicker application of constant volume combustion technology in gas turbines and power generation applications

Reductie milieudruk voedsel : met nadruk op voedselverspilling door huishoudens

Het project "Reductie milieudruk voedsel met nadruk op voedselverspilling door huishoudens – 1e fase" is erop gericht om interventiestrategieën te verkennen, waarmee huishoudens gestimuleerd kunnen worden om voedselverspilling te verminderen. Het verminderen van voedselverspilling is een complexe oplossing voor een complex probleem: niet alleen huishoudens, maar ook andere ketenspelers en stakeholders dienen betrokken te worden om milieudruk in de voedselketen te realiseren