Biocompatibility of a new generation of covered metallic biliary stents in a treatment of malignant causes irreversibile cholestasis

Introduction: Overview of periprocedural and postprocedural (early and late) complication giving us access to determine the biological effects of treatment with covered versus uncovered metal stents in patients with irreversible jaundice malignant etiology. The Aim: The aim of study was to compare the clinical therapeutical effects of covered billiary stents versus uncovered billiary stents. Subjects and methods: We treated two groups of patients with irreversible cholestasis malignant etiology. In the first group of patients were used metal covering stents (MCS), while in the other group used metal uncovered stents (MNS). Results: We observed periprocedural complications, technical complications, and the early- to 30-day and late-to 6 months post-procedural complications such as parameters of biocompatibility of inserted endoprosthesis, i.e. biological effects on surrounding tissues. We found statistically high difference in the occurrence of bleeding and periprocedural complications in total of MNS group. In the category of early postprocedural complications, we found a statistically significant difference in the MNS groups for a hemobilia, post-stent cholangitis, stent occlusion, irritative symptoms and appetite loss, and also in the overall appearance of early postprocedural complications in MNS. In the category of late postprocedural complications statistically significant difference we found in the MNS reobstructive cholangitis, reobstruktive jaundice, irritative symptoms, loss of appetite and in full. The cause of stent dysfunction-obliteration, biliary encrustation, ingrowth, overgrowth and mucosal hyperplasia, tells us in favor of the biological effects of the insertion, point applied prosthesis and the final therapeutic effect achieved by them. Conclusions: According to our results, taking into account the parameters of biocompatibility under applicable definitions, authors can conclude that covered stents in contrast to the uncovered are meeting the criteria of almost ideal biological prostheses

Izomerizacija i izračunavanje selektivnosti u procesu hidrogenacije sojinog ulja

Soybean-oil hydrogenation process has been conducted in an industrial reactor by syn­thesized NICAT-2000 catalyst and by commercial G-70 catalyst under the same working conditions. Although this reaction includes a series of side processes, the first approxima­tion indicate that the basis of this mechanism is composed of a series of consecutive stages. The rate constants of consecutive stages and process selectivity are determined by the nu­merical analyzes of experimentally measured fatty acids concentrations. Synthesized NICAT-2000 catalyst has all attributes of the same-type standard commercial catalysts (G-70) with SLo > 40 (linoleic selectivity) and SLn = 2.5 (linolenic selectivity). An analysis of the experi­mentally obtained values confirmed the application of a numeric method used in determin­ing the selectivity of the soybean oil hydrogenation process and isomerization reaction model was proposed. .Proces hidrogenacije sojinog ulja, standardnih fizičko hemijskih karakteristika, vršen je u industrijskom reaktoru firme KRUPP, tip D404S, u fabrici D.D. 'Vital', Vrbas, katalizatorom NICAT-2000 sintetizovanim u IHTM-Centru za katalizu i hemijsko inženjerstvo i komercijalnim katalizatorom G- 70 pod istim uslovima rada. Mada ova reakcija hidrogenacije jestivog sojinog ulja obuhvata i niz bočnih procesa, u prvoj aproksimaciji se može smatrati da osnovu mehanizma čini niz konsekutivnih stupnjeva. Numeričkom analizom eksperimentalno izmerenih koncentracija C18 masnih kiselina, određene su konstante brzina konsekutivnih stupnjeva i parametri selektivnosti procesa. Sintetizovani katalizator NICAT-2000 poseduje sve atribute standardnih komercijalnih katalizatora istoga tipa (G-70) sa selektivnostima: SLo > 40 (prema linolnoj kiselini) i SLn = 2.5 (prema linoleinskoj kiselini). Analizom eksperimentalno dobijenih vrednosti potvrđena je primena upotrebljenog numeričkog postupka u određivanju selektivnosti procesa hidrogenacije sojinog ulja i ponuđen je reakcioni model geometrijske izomerizacije

Izomerizacija i izračunavanje selektivnosti u procesu hidrogenacije sojinog ulja

Soybean-oil hydrogenation process has been conducted in an industrial reactor by syn­thesized NICAT-2000 catalyst and by commercial G-70 catalyst under the same working conditions. Although this reaction includes a series of side processes, the first approxima­tion indicate that the basis of this mechanism is composed of a series of consecutive stages. The rate constants of consecutive stages and process selectivity are determined by the nu­merical analyzes of experimentally measured fatty acids concentrations. Synthesized NICAT-2000 catalyst has all attributes of the same-type standard commercial catalysts (G-70) with SLo > 40 (linoleic selectivity) and SLn = 2.5 (linolenic selectivity). An analysis of the experi­mentally obtained values confirmed the application of a numeric method used in determin­ing the selectivity of the soybean oil hydrogenation process and isomerization reaction model was proposed. .Proces hidrogenacije sojinog ulja, standardnih fizičko hemijskih karakteristika, vršen je u industrijskom reaktoru firme KRUPP, tip D404S, u fabrici D.D. 'Vital', Vrbas, katalizatorom NICAT-2000 sintetizovanim u IHTM-Centru za katalizu i hemijsko inženjerstvo i komercijalnim katalizatorom G- 70 pod istim uslovima rada. Mada ova reakcija hidrogenacije jestivog sojinog ulja obuhvata i niz bočnih procesa, u prvoj aproksimaciji se može smatrati da osnovu mehanizma čini niz konsekutivnih stupnjeva. Numeričkom analizom eksperimentalno izmerenih koncentracija C18 masnih kiselina, određene su konstante brzina konsekutivnih stupnjeva i parametri selektivnosti procesa. Sintetizovani katalizator NICAT-2000 poseduje sve atribute standardnih komercijalnih katalizatora istoga tipa (G-70) sa selektivnostima: SLo > 40 (prema linolnoj kiselini) i SLn = 2.5 (prema linoleinskoj kiselini). Analizom eksperimentalno dobijenih vrednosti potvrđena je primena upotrebljenog numeričkog postupka u određivanju selektivnosti procesa hidrogenacije sojinog ulja i ponuđen je reakcioni model geometrijske izomerizacije

Modelling cholesterol effects on the dynamics of the hypothalamic-pituitary-adrenal (HPA) axis

A mathematical model of the hypothalamic-pituitary-adrenal (HPA) axis with cholesterol as a dynamical variable was derived to investigate the effects of cholesterol, the primary precursor of all steroid hormones, on the ultradian and circadian HPA axis activity. To develop the model, the parameter space was systematically examined by stoichiometric network analysis to identify conditions for ultradian oscillations, determine conditions under which dynamic transitions, i.e. bifurcations occur and identify bifurcation types. The bifurcations were further characterized using numerical simulations. Model predictions agree well with empirical findings reported in the literature, indicating that cholesterol levels may critically affect the global dynamics of the HPA axis. The proposed model provides a base for better understanding of experimental observations, it may be used as a tool for designing experiments and offers useful insights into the characteristics of basic dynamic regulatory mechanisms that, when impaired, may lead to the development of some modern-lifestyle-associated diseases

Surface chemistry, thermal stability and structural properties of graphene oxide/12-tungstophosphoric acid nanocomposite

In recent years the nanocomposites of graphene oxide (GO) and different inorganic and organic compounds have shown great potential for charge storage applications. In present work we have investigated the influence of 12-tungstophosphoric acid (WPA) on surface chemistry of graphene oxide and thermal stability of nanocomposite. For this purpose nanocomposites with different mass ratios of GO and WPA were prepared. The thermal stability of nanocomposites was investigated by thermogravimetric and differential thermal analysis (TGA-DTA) while changes in surface chemistry of GO and structural properties of WPA were investigated by Fourier transform infrared spectroscopy (FTIR) and temperature programmed desorption (TPD) method. The TGA-DTA measurements of composites have shown that the major mass loss, due to carbon combustion, is shifted to higher temperatures (~500 °C vs. 380 °C of pure GO). Furthermore, when the amount of WPA is higher than 25 mass percent the nanocomposites start to act like individual components, which was also confirmed by FTIR analysis. The amount of surface oxygen groups, monitored by both TPD and FTIR methods, showed ˝V˝ shaped dependence from the quantity of WPA with minimum at about 12 mass percent of WPA. At the same time, the FTIR spectra revealed the structural changes of WPA, displayed as shifting and splitting of characteristic bands of Keggin anion structure

Surface chemistry, thermal stability and structural properties of graphene oxide/12-tungstophosphoric acid nanocomposite

In recent years the nanocomposites of graphene oxide (GO) and different inorganic and organic compounds have shown great potential for charge storage applications. In present work we have investigated the influence of 12-tungstophosphoric acid (WPA) on surface chemistry of graphene oxide and thermal stability of nanocomposite. For this purpose nanocomposites with different mass ratios of GO and WPA were prepared. The thermal stability of nanocomposites was investigated by thermogravimetric and differential thermal analysis (TGA-DTA) while changes in surface chemistry of GO and structural properties of WPA were investigated by Fourier transform infrared spectroscopy (FTIR) and temperature programmed desorption (TPD) method. The TGA-DTA measurements of composites have shown that the major mass loss, due to carbon combustion, is shifted to higher temperatures (~500 °C vs. 380 °C of pure GO). Furthermore, when the amount of WPA is higher than 25 mass percent the nanocomposites start to act like individual components, which was also confirmed by FTIR analysis. The amount of surface oxygen groups, monitored by both TPD and FTIR methods, showed ˝V˝ shaped dependence from the quantity of WPA with minimum at about 12 mass percent of WPA. At the same time, the FTIR spectra revealed the structural changes of WPA, displayed as shifting and splitting of characteristic bands of Keggin anion structure

Surface chemistry, thermal stability and structural properties of graphene oxide/12-tungstophosphoric acid nanocomposite

In recent years the nanocomposites of graphene oxide (GO) and different inorganic and organic compounds have shown great potential for charge storage applications. In present work we have investigated the influence of 12-tungstophosphoric acid (WPA) on surface chemistry of graphene oxide and thermal stability of nanocomposite. For this purpose nanocomposites with different mass ratios of GO and WPA were prepared. The thermal stability of nanocomposites was investigated by thermogravimetric and differential thermal analysis (TGA-DTA) while changes in surface chemistry of GO and structural properties of WPA were investigated by Fourier transform infrared spectroscopy (FTIR) and temperature programmed desorption (TPD) method. The TGA-DTA measurements of composites have shown that the major mass loss, due to carbon combustion, is shifted to higher temperatures (~500 °C vs. 380 °C of pure GO). Furthermore, when the amount of WPA is higher than 25 mass percent the nanocomposites start to act like individual components, which was also confirmed by FTIR analysis. The amount of surface oxygen groups, monitored by both TPD and FTIR methods, showed ˝V˝ shaped dependence from the quantity of WPA with minimum at about 12 mass percent of WPA. At the same time, the FTIR spectra revealed the structural changes of WPA, displayed as shifting and splitting of characteristic bands of Keggin anion structure

Dynamic transitions in a model of the hypothalamic-pituitary-adrenal axis

Dynamic properties of a nonlinear five-dimensional stoichiometric model of the hypothalamicpituitary-adrenal (HPA) axis were systematically investigated. Conditions under which qualitative transitions between dynamic states occur are determined by independently varying the rate constants of all reactions that constitute the model. Bifurcation types were further characterized using continuation algorithms and scale factor methods. Regions of bistability and transitions through supercritical Andronov-Hopf and saddle loop bifurcations were identified. Dynamic state analysis predicts that the HPA axis operates under basal (healthy) physiological conditions close to an Andronov-Hopf bifurcation. Dynamic properties of the stress-control axis have not been characterized experimentally, but modelling suggests that the proximity to a supercritical Andronov-Hopf bifurcation can give the HPA axis both, flexibility to respond to external stimuli and adjust to new conditions and stability, i.e., the capacity to return to the original dynamic state afterwards, which is essential for maintaining homeostasis. The analysis presented here reflects the properties of a low-dimensional model that succinctly describes neurochemical transformations underlying the HPA axis. However, the model accounts correctly for a number of experimentally observed properties of the stress-response axis. We therefore regard that the presented analysis is meaningful, showing how in silico investigations can be used to guide the experimentalists in understanding how the HPA axis activity changes under chronic disease and/or specific pharmacological manipulations

Results of the modernization of the electrostatic precipitator at unit B1 of the Thermal Power Plant Kostolac B

The electrostatic precipitator system of the lignite fired 350 MWe unit B1 of Thermal Power Plant Kostolac B has been modernized during 2014. The results of complex in site measurements, performed in the frame of performance control test at the beginning of the exploitation period of the upgraded electrostatic pre-cipitator proved that, under normal and guarantee working conditions of the boiler and precipitator, the emission of particulate matter do not exceed limiting value. After the period of precipitator further adjustments, five series of meas-urements in the frame of acceptance test were performed in accordance with rel-evant standards. This paper presents results of the investigation of particulate matter concentration, laboratory analysis of the lignite, fly and bottom ash sam-ples, working parameters of the unit and upgraded electrostatic precipitator as well as results of the calculations. The averaged mean particulate concentration at the exit of upgraded electrostatic precipitator of the unit B1 during Acceptance test was below guaranteed value. It is confirmed that adjustments of electrostatic precipitator electrical parameters have improved electrostatic precipitator effi-ciency, as well that electrostatic precipitatorcould work highly efficiently in en-ergy save mode with lower power consumption. © 2018 Society of Thermal Engineers of Serbia

Basic ISO standards related to the quality and safety/security in health care institutions

Health systems are under significant pressure in many countries. Every day, with the introduction of new methods/techniques, expensive equipment of high technological value, the latest very expensive drugs... the price of health care is growing much faster than the growth of the national product and the most developed countries, despite the fact that in many countries the percentage of health expenditures in the national product is growing. Funding constraints in health systems are evident even in wealthy countries. The cost of health care is significantly influenced by: the increase in the number of the population, changes in the age structure of the population, constant demands for increasing the level of quality of health services, as well as an increase in the demand for new services. The application of international management standards in healthcare institutions and in state institutions in charge of healthcare can significantly alleviate evident problems in healthcare