The effects of restraint stress on voluntary ethanol consumption in rats.

Sixty Wistar rats (Rattus norvegicus) were assigned to 4 groups of 15 rats each: ethanol stress (ES), ethanol no-stress (EN), isocaloric stress (IS) and isocaloric no-stress (IN). The effect of restraint stress on daily intake of ethanol and a 0.72% solution of glucose was examined in an ABA design (stress-no stress-stress). During the stress phases, 2 groups were subjected to daily 15-min restraint stress, whereas 2 groups were placed in different cages for 15 min as a control. All 4 groups were then given 6-hr access to their assigned liquid alone for 4 days followed by a choice between their assigned liquid and water on the 5th day. The ES group significantly increased their ethanol intake (g/kg) compared to the EN group on choice days but not on forced days. Percentage preference for ethanol was significantly greater and increased at a faster rate over the 75-day testing period compared with the EN group. However, total ethanol consumption (g/kg) and percentage preference did not vary as a function of phase. It is notable that the effects of restraint stress on ethanol self-administration persisted even after the stress schedule was removed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of machining conditions on specific tangential forces

This paper deals with different hypotheses regarding the resistance of deformable material that is subject to plastic strain. For analysing cutting processes, a new cutting layout with a single shear plane is proposed here to calculate the specific tangential forces. The specific tangential forces in the different shear zones were examined by experiment to verify one of the hypotheses in question. These analyses verified that the forces depend fundamentally on cutting parameters and cutting layouts. Hence, it is necessary to take account of a correlation between yield point and deformation temperature, when determining the mechanical properties of the cutting material during machining. It is suggested here to determine the mechanical properties from the conditions compensating the hardening and the softening of the cutting material.     

Effect of skin temperature on multifrequency bioelectrical impedance analysis

This study assessed the effects of changes in skin temperature on multifrequency bioimpedance analysis (MF-BIA) and on the prediction of body water compartments. Skin temperature (baseline 29.3 +/- 2.1 degrees C) of six healthy adults was raised over 50 min to 35.8 +/- 0.6 degrees C, followed by cooling for 20 min to 26.9 +/- 1.3 degrees C, by using an external heating and cooling blanket. MF-BIA was measured at both distal (conventional) and proximal electrode placements. Both distal and proximal impedance varied inversely with a change in skin temperature across all frequencies (5-500 kHz). The change in proximal impedance per degree centigrade change in skin surface temperature was approximately 60% of distal impedance. The change in measured impedance at 50 kHz erroneously increased predicted total body water (TBW) by 2.6 +/- 0.9 liters (P < 0.001) and underpredicted fat mass by 3.3 +/- 1.3 kg (P < 0.0001). Computer modeling of the MF-BIA data indicated changes in predicted water compartments with temperature modifications; however, the ratio of extracellular water (ECW) to TBW did not significantly change (P < 0.4). This change in impedance was not due to a change in the movement of water of the ECW compartment and thus probably represents a change in cutaneous impedance of the skin. Controlled ambient and skin temperatures should be included in the standardization of BIA measurements. The error in predicted TBW is < 1% within an ambient temperature range of 22.3 to 27.7 degrees C (72.1-81.9 degrees F).     

Disialoganglioside G(D2) loss following monoclonal antibody therapy is rare in neuroblastoma

Ganglioside GD2 is abundant on human neuroblastoma (NB). Monoclonal antibody 3F8 targeted to GD2 may have imaging and therapeutic potential. Antigen-negative clones can escape immune-mediated attack, leading to clinical resistance or recurrence. Among 95 evaluable patients treated i.v. with 3F8 (94 stage 4 and 1 stage 3), 66 received nonradiolabeled 3F8, 11 received 131I-labeled 3F8 (8-28 mCi/kg) with autologous bone marrow rescue, and 18 received both forms of treatment. Prior to treatment, 91 patients tested positive for GD2 reactivity by bone marrow immunofluorescence (n = 68), tumor immunohistochemistry (n = 20), or diagnostic radioimmunoscintigraphy only (n = 3). Of 62 patients who had refractory or recurrent NB following 3F8 treatment, 61 (98%) tested positive for GD2 reactivity by bone marrow immunofluorescence (n = 51) or tumor immunohistochemistry (n = 10). The sole tumor that lost GD2 expression underwent phenotypic transformation into a pheochromocytoma-like tumor. The persistence of GD2 expression in refractory or recurrent NB suggests that complete antigen loss is an uncommon event and cannot account for treatment failure.     

Numerical methods for the solution of the degenerate nonlinear elliptic equations arising in optimal stochastic control theory

Three distinct but related results are obtained. First, an iterative method is derived for obtaining the solution of optimal control problems for Markov chains. The method usually converges much faster, and requires less computer storage space, than the methods of Howard or Eaton and Zadeh. Second, nonlinear finite difference equations, which "approximate" the nonlinear degenerate elliptic equation (2) arising out of the stochastic optimization problem (1), are found. The difference equations, and their solution, may have a meaning for the control problem even when it cannot be proved that (2) has a solution. The iterative methods for the iterative solution of these nonlinear systems are discussed and compared. Both converge to the solution, provided that the difference equations were derived using the method introduced in the paper; one, new to this paper, often much faster than the other (Theorem 2). In fact, the typical time required for the numerical solution is about the time required for a related linear problem. The method of obtaining the difference equations, and the proof of convergence of the associated iterative procedures, are illustrated by a detailed example. Finally, specific numerical results for a "minimum average time" type of optimization problem are presented and discussed.     

Psychological and physiological predictors of response to carbon dioxide challenge in individuals with panic disorder.

Past studies in nonclinical samples have found that suffocation fear, but not a behavioral index of carbon dioxide (CO?) sensitivity (i.e., breath-holding duration), predicts anxious response to CO? challenge. These associations were examined in individuals with panic disorder while adding more sensitive indices Of CO? sensitivity. Consistent with the earlier studies, the authors found that suffocation fear predicted anxious responding to CO? challenge but breath-holding duration did not. However, highly precise measures of CO? sensitivity, not included in earlier studies, did predict anxious challenge responding. These findings support the predictive value and possible etiological relevance of both specific psychological variables and physiological CO? sensitivity in panic vulnerability. Further work is still needed to determine whether the findings are specific to panic disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Gauss-Seidel numerical procedure for Markov stochastic games

Consider the problem of value iteration for solving Markov stochastic games. One simply iterates backward, via a Jacobi-like procedure. The convergence of the Gauss-Seidel form of this procedure is shown for both the discounted and ergodic cost problems, under appropriate conditions, with extensions to problems where one stops when a boundary is hit or if any one of the players chooses to stop, with associated costs. Generally, the Gauss-Seidel procedure accelerates convergence.