Vocational rehabilitation from a behavioral economics perspective.

Behavioral economics represents a synthesis of basic principles of economics and behavioral psychology that has become a major perspective for understanding addictions and health service utilization. The present article discusses the basic assumptions and concepts of behavioral economics as they apply to vocational rehabilitation (VR) services. The concepts of value and unit price, demand, elasticity, substitutes and complements, and discounting are examined within the context of VR and common choices of VR participants. Common models of VR, such as supported employment and transitional employment, are discussed from a behavioral economics perspective. Implications for VR programs and staff are identified. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A universal model for spike-frequency adaptation

Spike-frequency adaptation is a prominent feature of neural dynamics. Among other mechanisms, various ionic currents modulating spike generation cause this type of neural adaptation. Prominent examples are voltage-gated potassium currents (M-type currents), the interplay of calcium currents and intracellular calcium dynamics with calcium-gated potassium channels (AHP-type currents), and the slow recovery from inactivation of the fast sodium current. While recent modeling studies have focused on the effects of specific adaptation currents, we derive a universal model for the firing-frequency dynamics of an adapting neuron that is independent of the specific adaptation process and spike generator. The model is completely defined by the neuron's onset f-I curve, the steady-state f-I curve, and the time constant of adaptation. For a specific neuron, these parameters can be easily determined from electrophysiological measurements without any pharmacological manipulations. At the same time, the simplicity of the model allows one to analyze mathematically how adaptation influences signal processing on the single-neuron level. In particular, we elucidate the specific nature of high-pass filter properties caused by spike-frequency adaptation. The model is limited to firing frequencies higher than the reciprocal adaptation time constant and to moderate fluctuations of the adaptation and the input current. As an extension of the model, we introduce a framework for combining an arbitrary spike generator with a generalized adaptation current.     

C1 inhibitor-C1s complexes are internalized and degraded by the low density lipoprotein receptor-related protein

Like other serpin-enzyme complexes (SECs), proteinase-complexed C1 inhibitor (C1-INH) is rapidly cleared from the circulation and thought to be a neutrophil chemoattractant, suggesting that complex formation causes structural rearrangements exposing a domain which is recognized by specific cell surface receptors. However, the cellular receptor(s) responsible for the catabolism and potential mediation of chemotaxis by C1-INH-protease complexes remained obscure. To determine whether the SEC receptor mediates the binding and potential chemotaxis of C1-INH.Cs, we performed binding assays with HepG2 cells, neutrophils, and monocytes, and the results show that C1-INH.Cs neither bind to these cells nor cause a chemotactic response of neutrophils and monocytes. Furthermore, C1-INH.Cs, the COOH-terminal C1 inhibitor peptide, or the tetrameric C1-INH.Cs.Cr. C1-INH complex were found to be significantly less effective in competing with the SEC receptor ligand 125I-peptide 105Y for the binding to HepG2 cells than unlabeled 105Y, indicating that the SEC receptor does not sufficiently recognize C1-INH-protease complexes. The asialoglycoprotein receptor was also ruled out to be responsible for the removal of the heavily glycosylated C1-INH.Cs complex, since asialoorosomucoid did not compete for the clearance of C1-INH. 125I-Cs and asialoglycoprotein receptor knockout mice showed no alterations in the C1-INH.125I-Cs clearance rate. We found that C1-INH.125I-Cs complexes were efficiently degraded by normal murine fibroblasts expressing the low density lipoprotein receptor-related protein (LRP) and cellular degradation was significantly reduced by chloroquine and the receptor-associated protein, which is a potent inhibitor of the binding of all known ligands to LRP. Moreover, receptor-associated protein inhibited the in vivo clearance of C1-INH.125I-Cs and murine fibroblasts genetically deficient for LRP did not degrade C1-INH.125I-Cs. Our results demonstrate that C1-INH. Cs complexes do not stimulate neutrophil or monocytic chemotaxis but are removed by LRP, further underscoring its role as a serpin-enzyme complex clearance receptor.     

Comparative study on the expression of stress-response protein (srp) 72, srp 27, alpha B-crystallin and ubiquitin in brain tumours. An immunohistochemical investigation

The cardiac conduction system may be affected by various pathologic changes. Some of these changes are general and affect the nonconduction system tissues of the heart (atrophy, fibrosis, necrosis, segment deposition, mineral) and others are more localized to the conduction system (Lev and Lenegre disease). Pathologic conditions associated with atrial, junctional, and ventricular arrhythmias are reviewed.     

Rate characteristics for the reaction of carboxyl-modified polyamide with potassium hydroxide

Nylon 66 fiber, carrying 2.0 meq/g of carboxyl groups from radiation grafting of acrylic acid, was found to display chemical kinetics strongly first order with respect to the potassium hydroxide. The apparent rate constant k' remains nearly unchanged as the initial bath pH is varied from 8.3 to 10.5. At this point, the value of k' drops sharply, and continues to drop as the initial pH is increased. This discontinuity is attributed to a previously reported morphological transition indicated by a break in titration data at the corresponding equilibrium point of pH 9.2.     

Specific volume of polystyrene networks

We have described a method for the measurement of the specific volume of polymer networks at different degrees of swelling. We have observed a very small difference between the apparent specific volume of polystyrene in the swollen gel state and in solution in the same solvent and at the same polymer concentration. This indicates a small variation in the chain expansion with the degree of swelling. Moreover, our precise measurements of the swelling parameters confirm the interdispersion phenomenon as the main process for the swelling in a ‘theta’ solvent.     

Ultrafast charge separation at a polymer-single-walled carbon nanotube molecular junction

We have investigated the charge photogeneration dynamics at the interface formed between single-walled carbon nanotubes (SWNTs) and poly(3-hexylthiophene) (P3HT) using a combination of femtosecond spectroscopic techniques. We demonstrate that photoexcitation of P3HT forming a single molecular layer around a SWNT leads to an ultrafast (～430 fs) charge transfer between the materials. The addition of excess P3HT leads to long-term charge separation in which free polarons remain separated at room temperature. Our results suggest that SWNT-P3HT blends incorporating only small fractions (1%) of SWNTs allow photon-to-charge conversion with efficiencies comparable to those for conventional (60:40) P3HT-fullerene blends, provided that small-diameter tubes are individually embedded in the P3HT matrix.     

Psychometric profile of posttraumatic stress disorder, anxious, and healthy Vietnam veterans: Correlations with psychophysiologic responses.

Three groups of Vietnam combat veterans, posttraumatic stress disorder (PTSD, n?=?25), anxious (n?=?7) and healthy (n?=?18), completed a battery of psychometric tests. Measurement of psychophysiologic responses to imagery of individualized combat experiences followed the psychometrics. The PTSD Ss differed significantly from the healthy Ss on almost all measures but showed fewer differences from the anxious Ss. The typical PTSD S was characterized as anxious, depressed, prone to dissociation, and external in locus of control. Correlations with the physiologic responses supported the validity of psychometric scales specifically designed to measure PTSD but cast doubt on the interpretation of traditional measures of overreporting or dissimulation in this disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of operational parameters and material properties on the contact heat transfer in rotary kilns

The heat transfer by contact between the covered inner wall surface and the solid bed in a rotary kiln was experimentally investigated. An indirect heated batch rotary drum with a diameter of D = 600 mm and a length of L = 450 mm has been used. Inside the drum, a rotating and stationary measuring rod was installed, each assembled with 16 k-type thermocouples to measure the temperatures. Thus, the radial and circumferential temperature gradients within the solid bed were measured, and the contact heat transfer was determined from the heating of the bed. The effect on the contact heat transfer coefficient was estimated for the operational parameters of the drum, rotational speed (1, 3, 6 rpm) and filling degree (10%, 15%, 20%); the solid bed parameters, particle diameter (0.7, 1.3, 2.0 mm) and thermo physical properties (conductivity, heat capacity, density). As test material, quartz sand, glass beads and copper beads were used. The measured heat transfer coefficients were compared with theoretical calculations of four model approaches from the recent literature. A good agreement with just one of these model approaches could be achieved.