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We have studied the temperature and size dependence of the G and 2D phonon modes in graphene. It is shown that in a graphene monolayer the phonon energy decreases whereas the phonon damping increases with increasing temperature. The electron-phonon interaction leads to hardening whereas the fourth-order anharmonic phonon-phonon processes lead to softening of the phonon energy with increasing temperature. We have shown that the electron-phonon interaction plays an important role also by the dispersion dependence of the phonon G mode, by the observation of the Kohn anomaly. The G mode frequency decreases and damping increases, whereas the 2D phonon frequency and damping increase with increasing layer number. The temperature and size effects of the 2D mode are much stronger than those of the G mode.

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The phonon properties of multiferroic BiFeO(3) (BFO) nanoparticles are studied using a Green's function technique on the basis of the Heisenberg and the transverse Ising models, taking into account anharmonic spin-phonon and phonon-phonon interaction terms. The phonon spectrum is obtained for different exchange, magnetoelectric, and spin-phonon interaction constants. The influence of temperature, surface and size effects on the phonon energy and damping is discussed. The phonon energy and damping in BFO nanoparticles are greater in comparison to those in bulk BFO. The strong spin-phonon interactions lead to anomalies in the phonon spectrum around the magnetic and ferroelectric phase transitions. The influence of an applied magnetic field is studied, too. The predictions are consistent with experimental results.

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The investigation make historical analysis of the fundamental normative documents and publications of medical deontology. It study the rise and enrich of of the medico-deontological rules, which control the behavioral of the Bulgarian physicians during the last century. The authors put accent over the work of the famous Bulgarian legal medical man Professor Ivan Moskov (1894-1952) "Deontology- obligations and rights of the physician and short medical low" (1946). He offers a new division into periods.

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In vitro experiments were performed on smooth-muscle strips cut out in longitudinal and circular direction from the colon of Hirschsprung's patients who underwent an operation and from patients operated on for tumors of the sigmoid colon and rectum, serving as controls. The changes in the contractile activity of the smooth-muscle strips after carbachol applied cumulatively were examined and dose-response curves were plotted. The EC50 values for the circular strips from the aganglionic part of the colon were 6 x 10(-7) M in Hirschsprung's patients and 3.7 x 10(-8) M in control patients: the pD2 values were 6.23 and 7.43, respectively. This showed that the affinity of cholinoreceptors in the aganglionic part of the colon for carbachol was 16 times lower in Hirschsprung's patients as compared to control patients. The EC50 values for longitudinal strips from the ganglionic part of the colon were 2.6 x 10(-7) M in Hirschsprung's patients and 4 x 10(-8) M in control patients; pD2 values were 6.6 and 7.4, respectively. The affinity of cholinoreceptors in the smooth muscle of the ganglionic part of the colon for carbachol was also decreased (nearly 6.5 times) in Hirschsprung's patients as compared to controls.

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Postoperative intussusception is a rare but serious complication which occurs usually during the early postoperative period with intermittent, but progressing intestinal obstruction with characteristic appearance of mucus-bloody stools. Two children with postoperative intussusception have been observed among 381 children who have had abdominal operations during the last three years (1985-1987) (0.5 per cent). Various postoperative complications developed in 45 children (11.8 per cent), in 2 of them (4.4 per cent) the complication being intussusception. Both children were operated for tumors. In one (1 1/2 years old) the postoperative intussusception was not diagnosed until it was re-operated; the child died. In the second child (3 months old) the postoperative intussusception was diagnosed by clinical and X-ray examination; the ileocolic portion of the intussusception was reduced by pneumocoloscopy, while the ileo-ileal required re-operation with manual reduction. The infant survived. Early diagnosis of this rare postoperative complication, especially when mucus-bloody stools appear and pneumocoloscopy is performed, is feasible. Appropriate treatment will help for a favourable outcome.

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The distribution of substance P-, methionine-enkephalin-, somatostatin- and 5-hydroxytryptamine-immunoreactive nerve elements in Hirschsprung's disease was studied. It was compared to the distribution of the comparable nerve elements in the sigmoid colon and rectum of control children. A reduction of substance P-, methionine-enkephalin- and 5-hydroxytryptamine-immunoreactive fibers as well as a higher density of somatostatin-immunoreactive fibers were found in the aganglionic segment in Hirschsprung gut as compared to those in the ganglionic segment in Hirschsprung children and the large bowel in control children. The changes in the density of peptide- and 5-hydroxytryptamine-immunoreactive fibers suggest the participation of different transmitters or transmitter candidates in the pathogenesis of Hirschsprung's disease.

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The frequency of occurrence of the adrenergic, cholinergic, 5-hydroxytryptamine (5-HT)-, substance P (SP)-, methionine-enkephalin (met-Enk)- and somatostatin (SOM)-immunoreactive fibres innervating the smooth muscle of the large intestine in Hirschsprung and control children was compared. It was observed a higher frequency of catecholamine-fluorescence, acetylcholinesterase-positive and SOM-immunoreactive fibres in the muscularis externa and muscularis mucosa of the aganglionic segment in Hirschsprung gut as compared to that in the sigmoid colon and rectum in controls. In contrast, the frequency of SP-, met-Enk- and 5-HT-immunoreactive fibres in the aganglionic segment in Hirschsprung gut was lower than that in the controls. Ultrastructurally the cholinergic and adrenergic fibres occurred more often in the aganglionic segment in Hirschsprung gut than in the controls. A treatment with 6-OHDA and a fixation by Tranzer and Richards technique was used to confirm the nature of the adrenergic fibres. The p-type fibres occurred infrequently in the aganglionic segment of Hirschsprung gut. The results suggest that the change in the frequency of the nerves containing inhibitory transmitters may play an important role in the pathogenesis of Hirschsprung's disease.

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