Why do adults with mucoviscidosis refuse a medically recommended course of intravenous antibiotic therapy?

OBJECTIVE: To better understand the needs of spouses who provide care to spinal cord injury (SCI) survivors, by comparing their self-perceptions and complaints with those of their partners with disabilities and with those of spouses who do not provide care. DESIGN: Survey, including demographics, health concerns questionnaire, and administration of the Center for Epidemiologic Studies Depression Scale (CES-D), the Perceived Stress Scale (PSS), the Life Satisfaction Index (LSI-Z), and the Quality of Life and Individual Needs Questionnaire. SETTING: Two British SCI treatment centers, serving a defined population-based catchment area. PARTICIPANTS: One hundred twenty-four spouses of a longitudinally followed sample of SCI survivors, all of whom had been injured 23 or more years when the study was conducted in 1993. OUTCOME MEASURES: Scores on the above standardized tests, and responses to survey questions. RESULTS: Spouses had more depressive affect (p < .001) than their partners with disabilities, as measured by the CES-D. On the PSS, they exhibited no significant differences. Compared with spouses who were not caregivers, the caregiving spouses reported more physical stress (p = .005), emotional stress (p = .011), burnout (p = .007), fatigue (p = .002), and anger and resentment (p = .029). On the CES-D, they had more symptoms of depressive affect (p = .004) and somatic depression (p = .005). CONCLUSIONS: Spouses of long-term SCI survivors who fulfill a caregiving role report more symptoms of stress and depression than their partners with disabilities and other spouses who are not caregivers.     

Monte Carlo calculation of CRT screen efficiency

Abstract— The influence of phosphor grain size on overall CRT screen efficiency has been studied by Monte Carlo calculation of the energy absorption and the photon propagation in the phosphor screen. To calculate the energy absorption, the phosphor layer is modeled as a randomly packed layer of spheres with defined size distribution and screen weight. The absorbed energy in the phosphor grains is obtained from cross sections of the physical processes involved. The optical efficiency is calculated taking into account the scattering and absorption probability of the photons within the phosphor screen. The optimal screen efficiency which can be obtained for CRT screens with constant phosphor powder efficacy and aluminum reflectivity increases with increasing median grain size of the phosphor powder. Depending on the actual anode voltage applied, the CRT screen efficiency increases for a 32‐kV anode voltage by 15%, going from 3‐ to 8‐μm median grain size of the phosphor powder. Larger grains at this anode voltage do not further increase the efficiency. Grain‐size distribution has no noticeable influence on screen efficiency.     

Self‐assembly of ABA triblock copolymers based on functionalized polydimethylsiloxane and polymethyloxazoline

This study describes the responsive behavior of modified amphiphilic ABA triblock copolymers of polymethyloxazoline‐block‐poly(methylhydrosiloxane‐co‐dimethylsiloxane)‐block‐polymethyloxazoline (PMOX‐b‐P(MHS‐co‐DMS)‐b‐PMOX) when subjected to compression on the water surface or to ions in the water bulk phase. The hydrophobic middle block was functionalized with spacers bearing methyl 2‐hydroxybenzoate (Bz) or 18‐crown‐6 ether (Ce) groups. The behavior at the air–water interface was studied by measuring surface pressure versus mean molecular area (π–mmA) isotherms, and atomic force microscopy (AFM) was employed to investigate the morphology of Langmuir–Blodgett (LB) films after transfer to solid supports. Ion‐responsive self‐assembly was followed using light microscopy and can be understood on a molecular level by employing ¹H NMR spectroscopy. The π‐mmA isotherm of PMOX‐b‐P(MHS‐co‐DMS)‐b‐PMOX‐44Bz at the air–water interface had an extended pseudo‐plateau at a surface pressure of ca 22 mN m^?1 reflecting the coil to loop transformation of the hydrophobic middle block which was absent for the crown ether‐functionalized triblock copolymer. AFM images of LB films of PMOX‐b‐P(MHS‐co‐DMS)‐b‐PMOX‐44Bz showed dewetting effects of the polymer film after transfer to a silicon wafer. LB films of PMOX‐b‐P(MHS‐co‐DMS)‐b‐PMOX‐8Ce formed surface micelles having a size of ca 50–100 nm on the solid support. The ion sensitivities of the crown ether‐derivatized copolymers in solution were investigated by exposing polymeric vesicles to potassium, sodium and magnesium ions. Exposure to K⁺ and Na⁺ led to vesicle rupture and the formation of micro‐tubular structures, while Mg²⁺ had no effect on the vesicular structures as confirmed using light microscopy. Specific interactions between the crown ether‐derivatized polymer and ions were further elucidated from ¹H NMR experiments that indicated that K⁺ coordinated with the crown ether causing the dense packing to subside and leading to solubilization of the polymer in water. Copyright © 2010 Society of Chemical Industry     

Morphological influences on the electrical sintering process of Aerosol Jet and Ink Jet printed silver microstructures

The morphology of non-sintered printed structures depends on the applied printing process. Aerosol Jet and Ink Jet printed silver structures have been post-treated by furnace and electrical sintering. The resulting different morphologies of the structures were investigated optically by scanning electron microscopy and electrically by measuring the specific electrical resistances. Aerosol Jet printed silver required higher temperature during furnace sintering compared to Ink Jet printed structures to reach the same specific resistance. At temperatures above 200 °C an influence of the printing process on the final electrical resistance was not observed anymore. The electrical sintering with direct current of Aerosol Jet and Ink Jet printed silver microstructures showed lower specific resistances for the aerosol generated structures. Electrical sintering was extended by an electronic regulator module (ERM), which allows the sintering of the printed structures to a specified target resistance. While the average resistance of the structures is depending on accurate adjustment of the ERM, the maximum standard deviation of the resistance values is only 2 % which is much better than in conventional sintering.     

Fractionated administration of high-dose cyclophosphamide: influence on dose-dependent changes in pharmacokinetics and metabolism

PURPOSE: The alkylating agent cyclophosphamide (CP) is a prodrug that is metabolized to both cytotoxic and inactive compounds. We have previously shown that following dose escalation from conventional-dose (CD) to high-dose (HD) levels; the fraction of the dose cleared by bioactivation is significantly decreased (66% versus 48.5%) in favor of inactivating elimination pathways when the HD is given as a single 1-h infusion. Based on the concept of bioactivating enzyme saturation with increasing doses, we investigated the influence of fractionated application of HD-CP on dose-dependent changes in metabolism. PATIENTS AND METHODS: Plasma concentrations of CP (measured by high-performance liquid chromatography, HPLC) and urinary concentrations of CP and its major metabolites (quantified by [31P]-nuclear magnetic resonance spectroscopy; [31P]-NMR spectroscopy), were determined in four patients with high-risk primary breast cancer who received adjuvant chemotherapy including both CD-CP (500 mg/ m2 infused over 1 h) and split HD-CP (50 mg/kg infused over 1 h on each of 2 consecutive days (d): d1 and d2. RESULTS: (Data are given as mean values for CD and d1/d2 of HD, respectively). Systemic clearance (CL) of CP was similar during CD and d1 of HD, but significantly increased on d2 of HD (CL: 83 and 78/115 ml/min; P < 0.01 for d1 versus d2). The latter was translated into an increase in formation CL of both active (+ 16.4 ml/min) and inactive metabolites (+ 17.6 ml/ min) and reflects autoinduction of metabolism. As compared with CD-CP, no statistically significant decrease was observed in the relative contribution of bioactivation CL to overall CL during both days of HD (63% versus 57%/53%). Recovery of intact CP in 24-h urine corresponded to 24%, 29%, 22% of the dose (P < 0.05 for d1 versus d2 of HD). CONCLUSIONS: Following dose escalation of CP, dividing the high dose over 2 days instead of one single infusion may favorably impact the metabolism of CP in terms of bioactivation. In addition, on day 2 of a split regimen, renal elimination of CP is decreased, which implies that more drug is available for metabolism.     

Waveguide characterization of chiral material: theory

A new procedure to extract all three constitutive parameters of chiral material from waveguide measurements is presented. Two chiral slabs of different length must be measured. Their scattering parameters are inverted in a largely analytical way, complemented by a simple and fast convergent numerical algorithm. Tests with synthetic scattering data show the method to be very accurate and stable     

Flow injection analysis system for the supervision of industrial chromatographic downstream processing in biotechnology

Sugar beet molasses is a natural resource for various products used in daily life, ranging from sucrose to amino acids for pharmaceutical industry. The separation of molasses into these high value components is performed on a large scale by ion exchange/exclusion chromatography. A biosensor system was set up for the "in time" analysis of serine and sucrose during molasses desugarisation. D-Serine was analysed with the multi-enzyme system D-serine dehydratase/lactic dehydrogenase and photometric detection of the NADH consumed. Sucrose was determined with invertase/mutarotase/glucose oxidase and the oxygen consumed was monitored amperometrically. An analysis could be performed within 2-5 min by directly injecting samples from the chromatographic process into the flow injection analysis system. The determination range for the sucrose analysis was 0-2.5 gl-1 and for the analysis of D-serine 0-0.5 gl-1. The standard deviation for the measurement of D-serine was 1.7%.