Changes in medical stability upon admission to a rehabilitation unit

The implementation of Medicare's prospective payment system in acute care has coincided with a steady increase in medically unstable admissions to our freestanding rehabilitation facility. We investigated the consequences of these admissions by collecting medical information regarding transfers beginning in 1983. Patients requiring transfer back to the acute setting within 1 day of admission were considered medically unstable and their charts were reviewed. The number of patients requiring transfer back within 1 day increased from 1.5% of all first admissions to 3.1% in 1988 (Mantel - Haenszel chi 2 = 8.03, (df = 1), p < .01), but the increase among Medicare patients alone was not significant. This progressive increase was most pronounced in the cerebrovascular accident and spinal cord injury populations. Beginning in 1988, an intensified preadmission evaluation program was implemented, resulting in a significant decline in unstable patient transfers from hospitals where our consultants were on staff. Physiatric consultations at referral institutions decreased the number of unstable patients at admission.     

Use of process signals for tool wear progression sensing in drilling small deep holes

Detailed knowledge about the relation between wear progression of a cutting tool and the cutting forces generated is of paramount importance for the development of a tool condition monitoring strategy. This paper discusses the changes in the different process signals with progressing tool wear of small diameter twist drills (D=1.5 mm), when drilling boreholes having a depth of 10 times the diameter in plain carbon steel using MQL. The effect of different wear patterns on the process signals is presented. Furthermore, several features, which evolve over the life of the drills, are identified and extracted from the process signals. Knowledge about the evolution of these features can support the user to determine the final tool life stage, so that the drill can be replaced before the final fracture occurs.     

A Methodology for the Evaluation of a GPS Receiver Performance in Telematics Applications

This paper presents a methodology to evaluate the position availability of automotive grade global positioning system (GPS) receivers intended for Telematics applications utilizing a multichannel GPS satellite signal simulator in a controlled laboratory environment. Initially, field testing of two distinct GPS receivers was conducted in an urban canyon environment and a foliage environment to assess each receiver's position availability performance. Test scenarios were then developed on a multichannel GPS satellite signal simulator in order to create controlled and repeatable stimuli to the GPS receivers. The scenarios take into account the actual satellite constellations at the same day, time, and locations of the field data collections. Furthermore, the number of visible satellites and power levels was adjusted in order to stimulate the hardware tracking sensitivity, hardware acquisition sensitivity, dynamic range, and navigation filter design, all of which impact position availability for GPS receivers. Quantitative results demonstrated good correlation between the results obtained using the developed test scenarios and the results from the field testing. The proposed methodology will result in reducing validation cost and time to market for automotive Telematics products     

Pharmacokinetics of liposomal amphotericin B (Ambisome) in critically ill patients

The liposomal formulation of amphotericin B (AmBisome) greatly reduces the acute and chronic side effects of the parent drug. The present study describes the pharmacokinetic characteristics of AmBisome applied to 10 patients at a dose of 2.8 to 3.0 mg/kg of body weight and compares them to the pharmacokinetics observed in 6 patients treated with amphotericin B deoxycholate at the standard dose of 1.0 mg/kg. Interpatient variabilities of amphotericin B peak concentrations (Cmax) and areas under concentration-time curves (AUC) were 8- to 10-fold greater for patients treated with AmBisome than for patients treated with amphotericin B deoxycholate. At the threefold greater dose of AmBisome, median Cmaxs were 8.4-fold higher (14.4 versus 1.7 microg/ml) and median AUCs exceeded those observed with amphotericin B deoxycholate by 9-fold. This was in part explained by a 5.7-fold lower volume of distribution (0.42 liters/kg) in AmBisome-treated patients. The elimination of amphotericin B from serum was biphasic for both formulations. However, the apparent half-life of elimination was twofold shorter for AmBisome (P = 0.03). Neither hemodialysis nor hemofiltration had a significant impact on AmBisome pharmacokinetics as analyzed in one patient. In conclusion, the liposomal formulation of amphotericin B significantly (P = 0.001) reduces the volume of drug distribution, thereby allowing for greater drug concentrations in serum. The low toxicity of AmBisome therefore cannot readily be explained by its serum pharmacokinetics.     

Vacuum Insulation Panels – Exciting Thermal Properties and Most Challenging Applications

Vacuum insulation panels (VIPs) have a thermal resistance that is about a factor of 10 higher than that of equally thick conventional polystyrene boards. VIPs nowadays mostly consist of a load-bearing kernel of fumed silica. The kernel is evacuated to below 1 mbar and sealed in a high- barrier laminate, which consists of several layers of Al-coated polyethylene (PE) or polyethylene terephthalate (PET). The laminate is optimized for extremely low leakage rates for air and moisture and thus for a long service life, which is required especially for building applications. The evacuated kernel has a thermal conductivity of about 4 × 10⁻³ W · m⁻¹ · K⁻¹ at room temperature, which results mainly from solid thermal conduction along the tenuous silica backbone. A U-value of 0.2 W · m⁻² · K⁻¹ results from a thickness of 2 cm. Thus slim, yet highly insulating fa?ade constructions can be realized. As the kernel has nano-size pores, the gaseous thermal conductivity becomes noticeable only for pressures above 10 mbar. Only above 100 mbar the thermal conductivity doubles to about 8 × 10⁻³ W · m⁻¹ · K⁻¹, such a pressure could occur after several decades of usage in a middle European climate. These investigations revealed that the pressure increase is due to water vapor permeating the laminate itself, and to N₂ and O₂, which tend to penetrate the VIP via the sealed edges. An extremely important innovation is the integration of a thermo-sensor into the VIP to nondestructively measure the thermal performance in situ. A successful “self-trial” was the integration of about 100 hand-made VIPs into the new ZAE-building in Würzburg. Afterwards, several other buildings were super-insulated using VIPs within a large joint R&D project initiated and coordinated by ZAE Bayern and funded by the Bavarian Ministry of Economics in Munich. These VIPs were manufactured commercially and integrated into floorings, the gable fa?ade of an old building under protection, the roof and the facades of a terraced house as well as into an ultra-low-energy “passive house” and the slim balustrade of a hospital. The thermal reliability of these constructions was monitored using an infrared camera.Invited paper presented at the Seventh European Conference on Thermophysical Properties, September 5-8, 2005, Bratislava, Slovak Republic.     

Modification of CaCO3 precipitation rates by water-soluble nacre proteins

Mineral growth in nacre and other CaCO₃-containing biominerals is controlled by biopolymers. Water-soluble proteins were extracted from nacre of the sea snail Haliotis laevigata by dissolving the mineral phase with 6% acetic acid. The influence of this protein mixture on CaCO₃ precipitation rates was investigated at different concentrations. A well-established assay for measuring the pH-value during CaCO₃ precipitation with and without protein additives was extended by calculating maximum precipitation rates from the pH-values. It could be shown that precipitation rates are greatly influenced by the mixtures of water-soluble nacre proteins. At very low protein concentrations (0.02 μg/ml) a rate enhancement in comparison to the pure supersaturated calcium carbonate solution by a factor of 1.4 was observed. At higher protein concentrations, a strong inhibitory effect occurred, with total inhibition at concentrations of 1.0 μg/ml and higher. Two unspecific proteins (bovine serum albumin and lysozyme) showed little or no modification of precipitation rates. In vivo, the function of the strong inhibition of CaCO₃ precipitation by nacre proteins at higher concentrations is presumably to prevent uncontrolled crystallization in the extrapallial fluid. The rate-enhancing capability of proteins at low concentrations may be explained by the presence of acidic and/or hydrophilic moieties.     

Optimized preparation of alumina based fillers for tuning composite properties

Alumina based particles were prepared from aluminium chloride hydroxide as starting material by sol-gel technique. One series of particles was doped with ferrous oxide. Both series of particles were calcinated at three different temperatures: 700?°C, 800?°C and 900?°C. Poly(methyl methacrylate), PMMA, was used as a matrix and two different types of alumina based particles were added into the matrix to form the composites. All composites consisted of 3?wt% of alumina based particles. The aim of this study was to examine whether and how the temperature of particle calcination affects the microhardness and mechanical properties of the composite. The particles were characterized by the X-ray diffraction (XRD) and physical absorption methods. The morphology of the composites was examined using a field emission scanning electron microscope (FESEM). The microhardness of composites was measured using a traditional Vickers hardness (HV) method. The mechanical characteristics of obtained composites were determined using tensile test and impact testing.     

High-resolution capillary zone and gel electrophoresis of structurally similar amphipathic glutathione conjugates based on interaction with beta-cyclodextrins

The tripeptide glutathione is a prominent intracellular constituent that provides protection against genotoxic and carcinogenic electrophiles and is also a component of several biological signal substances. Glutathione conjugates, free glutathione, and glutathione disulfide contain charged amino acid residues, which contribute to solubility in aqueous media. However, the amphipathic nature of glutathione conjugates and the small differences that may distinguish the S substituents, pose analytical problems in their resolution. The present study demonstrates how homologous S-alkyl and S-benzyl conjugates of high structural similarity can be efficiently resolved by capillary electrophoresis. Inclusion of beta-cyclodextrins in the buffer or in a polyacrylamide gel affords baseline separation of the analytes. The separation methods described are applicable to enzyme assays in vitro and to the identification and quantification of glutathione conjugates of importance in toxicology and physiology. The contribution of beta-cyclodextrin to the separation is primarily based on interactions between its hydrophobic cavity and the S-alkyl and S-benzyl groups of the analytes.