Controlled Oxidation of Cobalt Nanoparticles to Obtain Co/CoO/Co3O4 Composites with Different Co Content.

The paper studies patterns of interaction of electroexplosive Co nanoparticles with air oxygen during heating. The characteristics of Co nanoparticles and composite Co/CoO/Co3O4 nanoparticles formed as a result of oxidation were studied using transmission electron microscopy, X-ray phase analysis, thermogravimetric analysis, differential scanning calorimetry, and vibrating sample magnetometry. It was established that nanoparticles with similar morphology in the form of hollow spheres with different content of Co, CoO, and Co3O4 can be produced by varying oxidation temperatures. The influence of the composition of composite nanoparticles on their magnetic characteristics is shown.

Causes of repeated remodeling of left ventricle after Dor procedure.

OBJECTIVES: To reveal morphological factors causing unfavorable follow-up outcome of surgical treatment of patients with ischemic cardiomyopathy (ICMP) and with left ventricle (LV) aneurysm according to the data of intraoperative biopsies of LV myocardium and right atrium (RA) auricle. METHODS: The object of the study was to examine biopsy material of LV myocardium and RA auricle from 36 patients with ICMP. Clinical criteria of patients' inclusion into the study were: ESI LV >80 ml/m(2), EDP LV >30 mmHg, LV EF <40%, presence of akinetic and dyskinetic areas in LV, angina of II-IV class CCS, heart failure of II-IV class NYHA. The following morphometrical parameters were estimated for revelation of postoperative remodeling risk factors: parenchymal-stromal ratio (PSR), trophic index (TI), pericapillar diffusion zone (PDZ), Kernogan index (KI) and specific volume of granules of natriuretic factor (NUF) in atrial cardiomyocytes. RESULTS: In all the patients LV EF increased significantly (from 36.4+/-4.1% to 46.3+/-4.2%) (P<0.05) in the early postoperative period; LV EDI decreased (from 139.3+/-11.2 ml/m(2) to 108.4+/-8.9 ml/m(2)) (P<0.05). In the follow-up period (one year) all the patients were divided into two groups: in 28 patients (the 1st group) volume of the cavity, contractile function of LV remained satisfactory. In the other eight patients (the 2nd group) there was significant decrease of LV EF (up to 33.9+/-10.2%) due to increase of LV EDI [up to 129.2+/-10.1 ml/m(2) (P<0.05)]. Grade of MR preoperatively was 1.21+/-0.5 and 1.47+/-0.9, correspondingly, for the patients with positive and negative changes in the follow-up postoperative period. Drawing morphological parallels of postoperative heart remodeling in patients with ICMP showed that diffusive, lymphocytic-macrophage inflammatory infiltration of myocardial stroma in combination with severe fibrosis (PSR<1.5), low TI (<0.015) and greater value of PDZ (>1000 microm) and KI (>1.6) of LV myocardium are the factors connected with unfavorable follow-up results of surgical treatment. Moreover, we showed an inverse correlative relationship between content of NUF granules in the cardiomyocytes of RA auricle and the outcomes of the Dor procedure. CONCLUSIONS: Thus, a combination of the foregoing features is a morphological predictor of postoperative heart remodeling in patients with ICMP.