A Technique for Totally Automated Audiometry

A means of combining two older audiometric techniques to yield a totally automated determination of hearing threshold levels using an integral audiometer?digital microprocessor is discussed. The design of the audiometric computer is briefly outlined.     

Multi-criteria decision making and uncertainty analysis for materials selection in environmentally conscious design

Around the globe, manufacturers are increasingly trying to design products that are as ecological as possible, which is leading to the establishment of new design methods focused on environmentally conscious design (ECD). Materials selection, as a key element in ECD, differs from traditional design by introducing three additional requirements: life cycle viewpoint, consideration on environmental impact and cost, and uncertainties in the product life cycle scenario. This paper presents a new multi-criteria decision making (MCDM) model and uncertainty analysis method for the environmentally conscious materials selection problem. The model is based on engineering analysis and life cycle simulation, and is constructed in such a way so that it contains uncertainties to be explored and may be executed during product design; it considers such issues as manufacturing and post-use processes such as recycling. The TOPSIS method is employed, and uncertainty analyses are performed for model flexibility. The model is applied to material selection for PC housing. The case study shows that the decision-making analysis can provide useful design guidelines and a criterion for materials selection to achieve Environmentally Conscious Design.     

Assessment of atrial septal defect morphology by transthoracic three dimensional echocardiography using standard grey scale and Doppler myocardial imaging techniques: comparison with magnetic resonance imaging and intraoperative findings

The properties of chemically cured and light-cured composite resins were recorded at baseline and at intervals over seven years, while the materials were exposed to controlled storage conditions as well as to various conditions typical of clinical situations. For chemically cured resins in clinical conditions, mechanical properties decreased, and working and setting times increased over four years; if refrigerated (controlled), properties remained constant past seven years. For light-cured resins, test results were constant over the entire seven-year test period regardless of storage conditions. An accelerated aging protocol was developed to allow for the evaluation of the relative storage stability of new and similar materials.     

A demonstration of pharmacokinetics and physiological modelling using a microcomputer for data capture and analysis

We describe a simple and inexpensive demonstration of mass transport and exchange using dye clearance from a hydrodynamic model. A microcomputer was used for data acquisition and storage, non-linear least squares curve fitting, compartmental analysis and parameter estimation. The system is useful for demonstrating the indicator-dilution technique for fluid volume measurement and compartmental analysis in pharmacokinetics.     

The surgical risk of pancreas transplantation in the cyclosporine era: an overview

BACKGROUND: Pancreas transplants are still associated with the highest surgical complication rate of all routinely performed solid organ transplants. To date, the impact of serious surgical complications in the cyclosporine era on perioperative patient morbidity, graft and patient survival, and hospital costs has not been analyzed in detail. STUDY DESIGN: We retrospectively studied surgical complications after 445 consecutive pancreas transplants (45% simultaneous pancreas-kidney [SPK], 24% pancreas after kidney [PAK], and 31% pancreas transplant alone [PTA]). Of these, 80% were primary transplants, 20% were retransplants. Cadaver donors were used in 92%, living related donors in 8%. To develop guidelines for their prevention and management, we studied the impact of significant surgical complications (intra-abdominal infections, vascular graft thrombosis, and anastomotic leak) requiring relaparotomy on graft and patient survival. RESULTS: Relaparotomy was required after 32% of all pancreas transplants (SPK: 36%, PAK: 25%, PTA: 16% [p = 0.04]). Perioperative mortality was 9%. Graft and patient survival rates were significantly lower for recipients with (versus without) relaparotomy. The most common procedures were drainage of intra-abdominal abscess with graft necrosectomy (50% of all relaparotomies) and transplant pancreatectomy (34%). The most common causes of relaparotomy were intra-abdominal infection, vascular graft thrombosis, and anastomotic leak. Intra-abdominal infection occurred in 20% (SPK: 18%, PAK: 24%, PTA: 20% [p = NS]). The rate was significantly higher for living related donor (42%) versus cadaver donor (18%) recipients and for those with enteric-drained (39%) versus bladder-drained (18%) transplants. Graft and patient survival rates were significantly lower for recipients with (versus without) intra-abdominal infection. Outcome was better after bacterial (versus fungal) infections. For SPK recipients, those not on dialysis before the transplant had significantly higher graft survival than those on dialysis. Vascular graft thrombosis occurred in 12% of all recipients. The rate was significantly higher for PAK (21%) than for PTA (10%) and SPK (9%) recipients. It was significantly lower for recipients of grafts with donor iliac Y-graft reconstruction (versus all other types of arterial reconstruction) and with right-sided (versus left-sided) graft placement. Of note, patient survival was not different for recipients with versus without vascular graft thrombosis. The incidence of anastomotic or duodenal stump leaks was 10%; of these recipients, 70% required relaparotomy. Patient and graft survival rates were no different for recipients with versus without leaks. CONCLUSIONS: Serious surgical complications occurred in 35% of pancreas recipients and had a significant impact on patient and graft survival. Based on multivariate risk factor analyses, we recommend the following: donors over 45 years and those dying of cerebrocardiovascular disease should not be used; recipients over 45 years and those with a history of cardiac disease should be considered for a kidney transplant alone (KTA); surgical technique for graft procurement, preparation, and implantation should be meticulous; right-sided implantation and arterial Y-graft reconstruction should be performed when possible, since they had the highest success rates; when complications require relaparotomy, the focus must switch from graft salvage to life preservation; and the threshold for pancreatectomy should be low. Diagnosis should be timely, and treatment and relaparotomy expeditious. These cornerstones of success should help decrease the risk of surgical complications and mortality after pancreas transplants.     

A comparison of manufacturing and remanufacturing energy intensities with application to diesel engine production

Climate change reports and policies relating to end-of-use products, CO₂ emissions, and energy are causing manufacturers to examine their operations closely. Several reports have touted the economic and environmental benefits of remanufacturing, including claims of significant reductions in terms of energy and CO₂ emissions. However, large-scale remanufacturing of heavy equipment engine components has not been closely examined and no standard procedure exists to quantify the benefits of remanufacturing. A methodology is presented for determining the energy intensity and benefits of remanufacturing as compared to new manufacturing, and this is applied to a diesel engine example. These findings are used to estimate the embodied manufacturing/remanufacturing energy across multiple use cycles.     

High‐throughput microbial bioassays to screen potential New Zealand functional food ingredients intended to manage the growth of probiotic and pathogenic gut bacteria

A spectrophotometric bioassay was used to screen selected food ingredients intended for development of functional foods designed to influence the growth of gut bacteria. Dose–response profiles displaying Δ_growth, the magnitude of deviation from growth of controls, were generated for probiotics Lactobacillus reuteri, Lactobacillus rhamnosus, Bifidobacterium lactis and pathogens Escherichia coli, Salmonella Typhimurium and Staphylococcus aureus. Ingredients were manuka honey UMF?20+(dose‐dependently increased probiotics and decreased pathogens); bee pollen (biphasic growth effects against all); Rosehips and BroccoSprouts^® (increased all dose‐dependently); blackcurrant oil (little effect) and propolis (inhibited all strains). Ingredients were also bioassayed in pairs to assess desirable or undesirable synergistic interactions. Observed synergies included manuka honey (predominantly desirable); rosehips or BroccoSprouts® (desirable and undesirable); blackcurrant oil (desirable) and propolis (tended towards synergies reinforcing its antimicrobial effects), collectively revealing a complex web of interactions which varied by ingredient and bacterial strain. Manuka honey was particularly effective at influencing gut bacteria. The surprising frequency of undesirable synergistic interactions illustrates the importance of pre‐testing potential ingredient combinations intended for use in functional foods.     

Fabrication of Optically Transparent and Electrooptic Strontium Barium Niobate Ceramics

The tetragonal tungsten bronze (TTB) type of Sr _x Ba_{1− x} ^m Nb₂O₆ (SBN) (0.5 ≤ x ≤ 0.75) was synthesized by a mixed-oxide route. Using the two-step densification process of pressureless sintering followed by oxygen HIPing, transparent ceramics were successfully fabricated. Microstructural, dielectric, optical, and electrooptic properties were investigated. All single-phase TTB-type SBN showed the characteristics of relaxor ferroelectrics. The extinction coefficients of the sample with the highest transparency were calculated from transmission spectra to be 30.4, 5.8, and 2.4 cm⁻¹ at 600, 1450, and 2000 nm, respectively. The linear electrooptic coefficients for SBN55, r ₃₃ and r ₁₃, were 46 × 10⁻¹² and 21 × 10⁻¹² m/V at 633 nm, respectively.