Synaptic delay learning in pulse-coupled neurons

We present rules for the unsupervised learning of coincidence between excitatory postsynaptic potentials (EPSPs) by the adjustment of postsynaptic delays between the transmitter binding and the opening of ion channels. Starting from a gradient descent scheme, we develop a robust and more biological threshold rule by which EPSPs from different synapses can be gradually pulled into coincidence. The synaptic delay changes are determined from the summed potential--at the site where the coincidence is to be established--and from postulated synaptic learning functions that accompany the individual EPSPs. According to our scheme, templates for the detection of spatiotemporal patterns of synaptic activation can be learned, which is demonstrated by computer simulation. Finally, we discuss possible relations to biological mechanisms.     

Recovered memories of childhood sexual abuse: Clinicians' practices and beliefs.

The issue of recovered memories of childhood sexual abuse (CSA) has stirred up a great deal of controversy in the field of psychology and in the public media. Recent court trials and television specials suggest that recovered and false memory cases occur often. Clinicians completed a survey designed to determine the prevalence of recovered memories for CSA in their clinical practices and to assess whether the recovered memory controversy had affected their treatment of female CSA victims. Despite the publicity the debate over memories of CSA has attracted, few cases of so-called recovered memory were reported. Even fewer cases of so-called false memory were reported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Crystal structure and amino acid sequence of Wolinella succinogenes L-asparaginase

Short-chain ubiquinone analogues act as electron acceptors and as inhibitors in the lymphoblast mitochondria of ND1/3460 mutants, which indicates structural changes in the ubiquinone-binding domain of Complex I in this mutant. The ND4/11778 mutant and two secondary ND5 mutants studied are associated with reductions of at least 50, 35 and 30% in the catalytic rate constant, respectively. However, the efficiency of oxidative phosphorylation is unaffected in all these ND mutants. The rate of respiration is only slightly limited by Complex I in lymphoblast mitochondria. Consequently, there is a 30-35% reduction in the electron flow through Complex I compared with that through Complex II, and an increased lactate/pyruvate ratio, in the ND1 and ND4 mutants, but these factors were unaffected in the secondary ND5 mutants. Energy metabolism is thus less severely affected in the secondary mutants than in the primary mutants, which supports the division into these two categories. An increased ubiquinone-10 content in the mitochondrial membrane of all the mutants, and enhanced succinate dehydrogenase and citrate synthase activities in the ND4 mutant, are proposed to be compensatory changes. The efficiency of these changes and the level of kinetic limitation of respiration by Complex I in each tissue are proposed to determine the clinical development of the disease.     

Implementation of the national cervical cancer screening in general practice and feasibility of a general practice-based call system: the GP''s opinion

A male fetus is described with multiple congenital abnormalities including craniosynostosis and bilateral radial aplasia. There are many similarities to the case recently reported by Imaizumi and Kuroki (Am J Med Genet 41: 162-163). These cases may represent a new syndrome with overlapping features of the Baller-Gerold and Roberts syndromes.     

Epoxy resins from fats. I. Epoxidized glycerides cured with phthalic anhydride

Summary and Conclusion Epoxy resins were made from phthalic anhydride and the following expoxidized fatty glycerides: neats-foot oil, lard oil, triolein, soybean oil, perilla oil, and trilinolein. Some physical properties of these resins were measured and tabulated. It has been shown that heat-distortion temperature, tensile strength, and modulus of elasticity increase with the unsaturation of the glyceride precursor of the epoxy intermediate. Presented at the fall meeting, American Oil Chemists' Society, Chicago, Ill., October 20–22, 1958. Eastern Regional Research and Development Division, Agricultural Research Service, United States Department of Agriculture.     

Plasma levels of carbamazepine and carbamazepine-10,11-epoxide during treatment of epilepsy

Carbamazepine and its epoxide in plasma were measured by liquid chromatography in 25 patients treated with a mean dose of carbamazepine of 12.5 +/- 3.3 mg/kg body weight. The mean concentrations of parent drug and metabolite were 5.4 +/- 2.5 mug/ml and 1.10 +/- 0.42 mug/ml, respectively. A singificant correlation was found between the plasma concentrations of the two compounds (r = 0.64; p less than 0.001), but marked interindividual variation existed in the ratio of carbamazepine to carbamazepine to epoxide. Based on simultaneous measurements in plasma and cerebrospinal fluid, the unbound fraction of carbamazepine in plasma was of the order of 20% as compared to 45% for the epoxide. Thirteen ambulant patients suffering from partial epilepsy with complex symptomatology, who were already being treated with phenytoin in optimal doses (plasma level 14-20 mug/ml) were also given carbamazepine. At plasma levels of the latter of about 5 mug/ml there was no further reduction in the frequency of partial or generalized epileptic seizures. In five patients the dose was increased to produce plasma concentrations of 7 - 8 mug/ml. There was still no improvement and side-effects were seen in three patients.     

Metal soaps of wool wax acids as stabilizers for plasticized polyvinyl chloride

Copper, magnesium, lead, nickel, cobalt, manganese, iron, chromium, cadmium, and barium soaps of the wool wax acid fraction have been tested as stabilizers for plasticized polyvinyl chloride polymers. Barium, cadmium, and lead soaps performed well in the light stability evaluations. In the heat aging tests barium, magnesium, lead, and nickel soaps were superior while cadmium, and manganese soaps performed poorly. The copper, cobalt, iron, and chromium soaps were ineffective. Two tests for stability were employed: an accelerated light aging test and an accelerated heat aging test. Combinations of barium and cadmium soaps were tested for synergistic effects and found to be more effective as stabilizers than the individual soaps. Soaps made from fractions of acids by partitioning the whole wool wax acid fraction were also tested. Neither the hydroxy nor the non-hydroxy acid fraction soaps had as goad stabilizing properties for PVC as those of the whole acid fraction. Presented at the Spring Meeting of the American Oil Chemists' Society, St. Louis, Missouri, May 1–3, 1961. Eastern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.