Component innovations for lower cost mechanical vapor compression.

Despite significant capital and operating costs, mechanical vapor compression (MVC) remains the preferred technology for challenging brine concentration applications. This work seeks to assess the dependence of MVC costs on feedwater salinity and desired water recovery and to quantify the value of improved component performance or reduced component costs for reducing the levelized cost of water (LCOW) of MVC. We built a cost optimization model coupling thermophysical, heat and mass transfer, and technoeconomic models to optimize and identify low cost MVC system designs as a function of feedwater salinity and water recovery. The LCOW ranges over 3.6 to 6.1 $/m3 for seawater feed salinities of 25-150 g/kg and water recoveries of 40-80 %. We then perform sensitivity analysis on parameter inputs to isolate irreducible costs and determine high value component innovation targets. The LCOW was most sensitive to evaporator material costs and performance, including the overall heat transfer coefficient in the evaporator. Process and material innovations such as polymer-composite evaporator tubes that reduce evaporator costs by 25 % without reducing heat transfer performance by more than 10 % would result in MVC cost reductions of 8 %.

Early-onset prescription drug misuse in Indiana youth.

BACKGROUND: Based on 2018 national estimates, approximately 5-10% of youth between the ages of 12-17 report past year prescription drug misuse (PDM) in the United States. PDM among adolescents is associated with negative health outcomes and risk behaviors. The current study examined both the prevalence of PDM among diverse groups of adolescents and the association of alcohol and cigarette use with early PDM. METHODS: Data came from the cross-sectional state-based 2018 Indiana Youth Survey of students from grades 6-12, ranging in age from 10 to 17 years (n = 80,926). Lifetime PDM, alcohol, and cigarettes were assessed by self-report, including ages at first use. A series of analyses were conducted separately for non-Hispanic Black, non-Hispanic White, and Hispanic students. We estimated the prevalence of PDM. Likelihood of PDM was estimated using the Kaplan-Meier survivor function. Cox proportional hazards regression models estimated age at first PDM from ages at first use of alcohol and cigarettes. RESULTS: Three percent of non-Hispanic Black, 4% of non-Hispanic White, and 5% of Hispanic students reported PDM. Onset of smoking was associated with first PDM across adolescence for all groups. Onset of drinking was associated with first PDM among Hispanic students across adolescence. For Non-Hispanic Black and Non-Hispanic White students, likelihood of PDM was most pronounced during very early adolescence. CONCLUSIONS: Onset of alcohol and cigarette use were associated with of PDM among Indiana youth, suggesting that interventions aimed at preventing early smoking and drinking may also reduce PDM among youth.

A tailored, electronic textile conformable suit for large-scale spatiotemporal physiological sensing in vivo.

The rapid advancement of electronic devices and fabrication technologies has further promoted the field of wearables and smart textiles. However, most of the current efforts in textile electronics focus on a single modality and cover a small area. Here, we have developed a tailored, electronic textile conformable suit (E-TeCS) to perform large-scale, multimodal physiological (temperature, heart rate, and respiration) sensing in vivo. This platform can be customized for various forms, sizes and functions using standard, accessible and high-throughput textile manufacturing and garment patterning techniques. Similar to a compression shirt, the soft and stretchable nature of the tailored E-TeCS allows intimate contact between electronics and the skin with a pressure value of around ~25 mmHg, allowing for physical comfort and improved precision of sensor readings on skin. The E-TeCS can detect skin temperature with an accuracy of 0.1 °C and a precision of 0.01 °C, as well as heart rate and respiration with a precision of 0.0012 m/s2 through mechano-acoustic inertial sensing. The knit textile electronics can be stretched up to 30% under 1000 cycles of stretching without significant degradation in mechanical and electrical performance. Experimental and theoretical investigations are conducted for each sensor modality along with performing the robustness of sensor-interconnects, washability, and breathability of the suit. Collective results suggest that our E-TeCS can simultaneously and wirelessly monitor 30 skin temperature nodes across the human body over an area of 1500 cm2, during seismocardiac events and respiration, as well as physical activity through inertial dynamics.

Radiological predictors of cytoreductive outcomes in patients with advanced ovarian cancer.

OBJECTIVE: To assess site of disease on preoperative computed tomography (CT) to predict surgical debulking in patients with ovarian cancer. DESIGN: Two-phase retrospective cohort study. SETTING: West London Gynaecological Cancer Centre, UK. POPULATION: Women with stage 3 or 4, ovarian, fallopian or primary peritoneal cancer undergoing cytoreductive surgery. METHODS: Preoperative CT images were reviewed by experienced radiologists to assess the presence or absence of disease at predetermined sites. Multivariable stepwise logistic regression models determined sites of disease which were significantly associated with surgical outcomes in the test (n = 111) and validation (n = 70) sets. MAIN OUTCOME MEASURES: Sensitivity and specificity of CT in predicting surgical outcome. RESULTS: Stepwise logistic regression identified that the presence of lung metastasis, pleural effusion, deposits on the large-bowel mesentery and small-bowel mesentery, and infrarenal para-aortic nodes were associated with debulking status. Logistic regression determined a surgical predictive score which was able to significantly predict suboptimal debulking (n = 94, P = 0.0001) with an area under the curve (AUC) of 0.749 (95% confidence interval [95% CI]: 0.652, 0.846) and a sensitivity of 69.2%, specificity of 71.4%, positive predictive value of 75.0% and negative predictive value of 65.2%. These results remained significant in a recent validation set. There was a significant difference in residual disease volume in the test and validation sets (P < 0.001) in keeping with improved optimal debulking rates. CONCLUSIONS: The presence of disease at some sites on preoperative CT scan is significantly associated with suboptimal debulking and may be an indication for a change in surgical planning.

Haemodynamic effects of rocuronium during fentanyl anaesthesia: comparison with vecuronium.

Haemodynamic variables were measured following administration of rocuronium 0.6 mg.kg-1 or vecuronium 0.08 mg.kg-1 (approximately equivalent to 2 x ED95 doses) in patients anaesthetized with fentanyl 50 micrograms.kg-1 and scheduled to undergo elective coronary artery bypass grafting. There were increases in stroke volume index (+15%) and cardiac index (+11%), and a decrease in pulmonary capillary wedge pressure (-25%) following administration of rocuronium (P < 0.05). The changes in heart rate (+7%), mean arterial pressure (-5%), systemic vascular resistance (-12%) and other measured or derived indices were insignificant. In comparison the administration of vecuronium was associated with decreases in heart rate (-7%), mean pulmonary artery pressure (-17%), central venous pressure (-15%) and the rate-pressure product (-9%) (P < 0.05). The changes in mean arterial pressure (-7%), cardiac index (-6%) and systemic vascular resistance (-8%) following vecuronium were insignificant. There were no differences in any of the variables between rocuronium and vecuronium. The absolute values of all variables were, however, within acceptable clinical limits. There was no evidence of histamine release in any patient. The present study shows that rocuronium 0.6 mg.kg-1 is associated with changes of only small magnitude in haemodynamic variables.

Comparison of the haemodynamic effects of pipecuronium and pancuronium during fentanyl anaesthesia.

Haemodynamic variables were measured following administration of pipecuronium 70 micrograms.kg-1 and pancuronium 90 micrograms.kg-1 (approximately equivalent to 1.5 x ED95) in patients anaesthetised with fentanyl 50 micrograms.kg-1 and scheduled to undergo coronary artery bypass grafting. There were significant increases in heart rate (22%), mean arterial pressure (10%), cardiac index (16%), and the rate pressure product (35%) following administration of pancuronium. The absolute values of these parameters were, however, within acceptable clinical limits. Administration of pipecuronium produced minimal and insignificant changes in these parameters. Other measured or derived indices showed only small changes with both agents and these were generally insignificant. There were no incidences of significant bradycardia following pipecuronium administration. The results from the present study suggest that pipecuronium would have advantages for use in patients with significant cardiovascular disease.

Propofol sedation after open heart surgery. A clinical and pharmacokinetic study.

One hundred adult patients who required mechanical ventilation after open heart surgery for coronary revascularisation were studied. All received a standard premedication and a high dose opioid anaesthetic. On arrival in the intensive care unit they were allocated randomly to receive either propofol or midazolam to maintain sedation within a predetermined range. Patients who received propofol underwent extubation of the trachea, using standard criteria, after a mean time (log-transformed) of 7.6 minutes after sedation for approximately 17 hours. The corresponding time was 125 minutes in those given midazolam. There were significantly higher morphine requirements during sedation, and higher arterial carbon dioxide tensions 30 minutes after extubation of the trachea, in patients who received midazolam. Pharmacokinetic analysis in 20 patients showed that the elimination half-life of propofol was prolonged (470 minutes) and clearance was reduced (1.14 litres/minute) compared with subjects who had not undergone cardiopulmonary bypass. The rapid clinical recovery was reflected in a rapid redistribution half-life (13.4 minutes), but this was also longer than the redistribution time of 2-4 minutes in other patients.

A pharmacokinetic study of midazolam in paediatric patients undergoing cardiac surgery.

Midazolam 0.3 mg kg-1 was given as a single dose to three groups of children undergoing cardiac surgery to determine its pharmacokinetic profile in this situation. The first group, undergoing closed heart surgery, received the midazolam during the operation. The other groups underwent cardiopulmonary bypass (CPB) with and without complete circulatory arrest. Mean clearance was 512 ml kg-1 h-1 and mean elimination half-lives were 3.3 h following CPB, with a tendency to a higher clearance in those children who had not undergone bypass. In a subsequent part of the study, 10 children received an infusion of midazolam 0.05 mg kg-1 h-1, in combination with intermittent doses of morphine, in the postoperative period. Mean plasma midazolam concentrations consistent with adequate sedation were 80-100 ng ml-1 during the infusion. One child who had not undergone CPB had very low plasma concentrations of midazolam with the same rate of infusion, consistent with the tendency for higher clearance in this group in the bolus pharmacokinetic study.

Comparison of sufentanil-oxygen and fentanyl-oxygen anaesthesia for coronary artery bypass grafting.

Haemodynamic variables were compared in 40 adults undergoing coronary artery bypass grafting during anaesthesia induced with either sufentanil 5 micrograms kg-1 or fentanyl 25 micrograms kg-1 in combination with pancuronium 0.1 mg kg-1. Further doses of sufentanil 2.5 micrograms kg-1 or fentanyl 12.5 micrograms kg-1 were given before skin incision and again before sternotomy. All patients were receiving beta-adrenoceptor blocking therapy. Satisfactory induction of anaesthesia was produced with both drugs and opioid supplementation prevented any marked haemodynamic response to skin incision and to sternotomy. Following induction of anaesthesia, sufentanil produced the greater decrease in mean arterial pressure and left ventricular stroke work index which continued throughout the study. This suggests that, in the doses used in this study, sufentanil is preferable to fentanyl in patients with coronary artery disease.

Midazolam sedation following open heart surgery.

Midazolam given as hourly intermittent injections was compared with the same dose given by infusion for postoperative sedation in patients after cardiopulmonary bypass. A stable concentration was rapidly attained with the infusion whereas 6-8 h was required to attain stable plasma (trough) concentrations in the intermittent injection group. Plasma concentrations decreased rapidly to low values within 6 h of discontinuation of therapy. High plasma concentrations and a long (16 h) half-life were noted in one patient who may be a slow metabolizer of the drug.

Haemodynamic effects of vecuronium, pancuronium and atracurium in patients with coronary artery disease.

Thirty patients with ischaemic heart disease scheduled for coronary artery bypass grafting were randomly allocated to three equal groups. Following morphine, hyoscine and pentobarbitone premedication, anaesthesia was induced with diazepam 0.3 mg kg-1. Five minutes later neuromuscular blockade was induced with pancuronium 0.1 mg kg-1, vecuronium 0.1 mg-1 or atracurium 0.5 mg kg-1, followed after 6 min by fentanyl 25 micrograms kg-1. Pancuronium and atracurium caused significant increases in heart rate, while vecuronium induced little change. Systemic vascular resistance decreased significantly from 1515 dyn s cm-5 to 1200 dyn s cm-5 following atracurium. Cardiac index was increased transiently in the atracurium group, but a more sustained increase was observed following pancuronium. Nine patients in the atracurium group showed skin flushing and one developed skin weals.

Pharmacokinetics of diazepam and midazolam when used for sedation following cardiopulmonary bypass.

The water-soluble benzodiazepine, midazolam, was compared with diazepam for postoperative sedation in patients following cardiopulmonary bypass. Midazolam in repeated doses produced a stable plasma concentration within 4 h, showed no tendency to cumulation and was cleared rapidly following discontinuation. Similar doses of diazepam given with the same frequency produced plasma concentrations which were still increasing at the time of discontinuation and which were still greater than their baseline values 24 h later.

Haemodynamic changes during induction of anaesthesia with midazolam and diazepam (Valium) in patients undergoing coronary artery bypass surgery.

Midazolam 0.3 mg/kg and diazepam 0.5 mg/kg were used for induction of anaesthesia in two groups of 10 patients each undergoing coronary artery bypass surgery. Haemodynamic variables were measured during induction of anaesthesia, after pancuronium and following tracheal intubation. Haemodynamic indices were derived from these measurements using standard formulae. The induction of anaesthesia with midazolam produced a slight but significant increase in heart rate. There was a significant fall in systemic arterial pressure and pulmonary artery pressure following both drugs. Despite the fall in systemic arterial pressure, the cardiac index was maintained in patients who received midazolam. The cardio-stimulatory effect of laryngoscopy and tracheal intubation was not prevented by either of the benzodiazepines and morphine in the dosage used. Midazolam is a suitable alternative to diazepam as part of an intravenous induction regimen in patients with ischaemic heart disease.

The speed of onset and potency of althesin.

The speed of onset of anaesthesia with Althesin has been compared with that of other intravenous anaesthetics. Like thiopentone, Althesin appears to be a truly rapidly acting drug, producing sleep in one arm-brain circulation time. The relative potencies of the drugs studied were approximately Althesin 60 mulitre/kg equivalent to thiopentone 4 mg/kg, equivalent to methohexitone 1.2 mg/kg, although by some criteria Althesin 80 mulitre/kg is required to produce an effect equivalent to thiopentone 4 mg/kg.

Clinical studies of induction agents. XLIII: recovery from althesin--a comparative study with thiopentone and methohexitone.

A detailed assessment of recovery endpoints and a simple performance test were employed to investigate recovery from anaesthesia. 150 patients participated in a comparative study using different doses of Althesin, thiopentone and methohexitone. Althesin was found to be suitable anaesthetic agent for the outpatient practice, although recovery was not as rapid as that following methohexitone.