Probing the uniformity of hydrogen intercalation in quasi-free-standing epitaxial graphene on SiC by micro-Raman mapping and conductive atomic force microscopy.

In this paper, micro-Raman mapping and conductive atomic force microscopy (C-AFM) were jointly applied to investigate the structural and electrical homogeneity of quasi-free-standing monolayer graphene (QFMLG), obtained by high temperature decomposition of 4H-SiC(0001) followed by hydrogen intercalation at 900 °C. Strain and doping maps, obtained by Raman data, showed the presence of sub-micron patches with reduced hole density correlated to regions with higher compressive strain, probably associated with a locally reduced hydrogen intercalation. Nanoscale resolution electrical maps by C-AFM also revealed the presence of patches with enhanced current injection through the QFMLG/SiC interface, indicating a locally reduced Schottky barrier height (ΦB). The ΦB values evaluated from local I-V curves by the thermionic emission model were in good agreement with the values calculated for the QFMLG/SiC interface using the Schottky-Mott rule and the graphene holes density from Raman maps. The demonstrated approach revealed a useful and non-invasive method to probe the structural and electrical homogeneity of QFMLG for future nano-electronics applications.

[Multiple coronary endarteriectomy in patients with diffusial coronary disease]. / Mnozhestveni koronarni endarterektomii pri patsienti s difuzna koronarna bolest.

UNLABELLED: In recent years the profile of patients with CAD is continuously changing, often with previous operation or stenting. Multiple coronary endarterectomies have been utilized as an adjunct to CABG in this select group of patients to achieve complete revascularization because of the diffuse CAD. METHODS: Between January 1997 and December 2001 eighty eight consecutive patients undergoing first time CABG with more than two CE were compared with a control group of 967 patients undergoing CABG without CE. RESULTS: More than 9% of the CABG patients need two or more endarterectomies, with involvement of the RCA in 96% and LAD in 59%. The extended time of aortic clamping and the higher rate of perioperative MI lead to higher mortality in Group 1 without significant difference between groups. The 5 years survival was 69% in Group 1 and 84% in Group 2. CONCLUSIONS: The operative results--mortality and morbidity, are similar in both groups instead of the highest complexity of the procedures with multiple endarterectomies. The use of this method together with CABG allows complete revascularization in 10% of the operated patients with diffuse atherosclerosis.

[Effect of antegrade brain perfusion on neurogical complications after surgical treatment of aneurysm and dissection with circulatory arrest]. / Vliianie antegradnata mozuchna perfuziia vurkhu nevrologichnite uslozhneniia sled khirurgichno lechenie na anevrizmi i disekatsii s tsirkulatoren arest.

From January 2001 until December 2003 twenty patients have been operated for acute or chronic dissection with involvement of the aortic arch. 16 of them were men, and 4--women, with middle age of 57 years. Two methods of cerebral perfusion have been used--hypothermic circulatory arrest (HCA) or selective antegrade cerebral perfusion (ACP). Direct cannulation or suturing of vascular prosthesis to the brachiocephalic trunk has been used for ACP. Twelve (12) partial and 8 total arch replacements have been done. The duration of ACP (54 min.) is longer than the time of HCA (32 min.). The neurological postoperative complications--coma (7.6%) and ischemic encephalopathy (30.4%), were significantly lower in the group with ACP than in the group of the HCA--14.2% and 42.6% respectively. Overall mortality is 15%--3 patients dying after the 30th day. Preoperative hemodynamic instability and neurological symptoms are strongly related with postoperative neurological complications. The method of cerebral protection did not influence the mortality, but the postoperative neurological complications are significantly lower in the group with ACP. We recommend ACP in all cases of acute aortic dissection and all aneurisms with arch involvement needing extended surgical operation.

[Immunological and morphological comparisons in toxic goiter]. / Immunologicheskie i morfologicheskie sopostavleniia pri toksicheskom zobe.

Histostructural peculiarities of the toxic goiter tissue were compared with humoral parameters of the autoimmune aggression and with the lymphoblasttransformation intensity in 29 patients operated on for thyrotoxicosis. The intensity of intradermal hypersensitivity reaction of delayed type in response to homologous and autologous tissue of the toxic goiter was also investigated. The majority of the patients displayed marked signs of autoimmune aggression, regardless of the structure of the goiter parenchyma and the intensity of ilt lymphoid infiltration. Immunological disturbances increase with the rise in the clinical severity of thyrotoxicosis. It is suggested that immunological changes of toxic goiter have phasic development. Humoral manifestation of autoimmune aggression were marked and stable, whereas changes of cellular immunity were less significant and specific; they were apparently due to a secondary increase in the lymphocytic immunological activity.