Predictive parameters functioning arteriovenous fistula for hemodialysis in the elderly

© 2019, University of Kragujevac, Faculty of Science. All rights reserved. Elderly patients with end stage kidney disease represent a challenge for surgeons to create a vascular access. Determine predictive parameters functionality of the arteriovenous fistulas for hemodialysis in the elderly. The study was organized as a retrospective study at the Center for Dialysis, Clinic for Urology and Nephrology, Clinical Center Kragujevac. The study included patients older than 65 years with arteriovenous fistula thrombosis, in the period of four years, in which there is information on the length of the functioning fistula. The study included 48 patients, mean age 71.3±5.2 years, 29 (60%) men and 19 (40%) women. The data were analyzed according to gender and demographic structure, type of anastomosis, positioning, length of functioning fistulas, and the lumen diameter of the arteries and veins that are used to create a fistula. The median length of functioning arteriovenous fistula, based on Kaplan-Meier model, is 16 months (95% CI 6.9- 25.1). Median functioning for proximaly located fistulas was 24 months (range, 1-259), while median functioning in patient with distally located fistulas was 8 months (range, 1-96). The difference in relation to the positioning of the fistula was statistically significant (p=0.006). In univariate Cox regression model, a statistically significant predictor of the functioning of arteriovenous fistulae is fistula positioning (B=0.700; p=0.022). The predictive parameter of survival of arteriovenous fistulas in elderly is proximally located fistula

Limitations and opportunities for funding agriculture and rural development in the Republic of Serbia

Funding is one of the most important issues of agriculture and rural development of the Republic of Serbia, because insufficient financial resources allocated to this sector of the country's economy are considered the key limitation for better valorization of agricultural resources and the revitalization of rural areas. Agribusiness and rural development have a major socio-economic importance for the Republic of Serbia, which is supported by a number of strategic documents, development indicators and scientific and expert analysis implemented in the country and at a global level; therefore, the aim of this study is to determine whether it is necessary and possible to improve the funding of agricultural development and rural economy of the Republic of Serbia, in current conditions. The survey results indicate potential sources, i.e., the possible ways of funding agriculture and non-agricultural activities in the rural areas of the Republic of Serbia.Publishe

Corrugated thin metal films as couplers between propagating and surface modes for plasmonic enhancement of photocatalytic optofluidic microreactors

Surface plasmons polaritons (SPP) ensure extreme concentrations of electromagnetic near fields at interfaces between materials with negative and positive dielectric permittivity (i.e. between metals and dielectrics), usually several orders of magnitude compared to fields in free space. This is useful for a number of practical applications, including chemical and biological sensing, enhancement of photodetectors and improvement of photocatalytical reactions. One of the problems to be solved with plasmonic field localization is that wavevectors of SPPs may vastly exceed those of propagating waves, so that a coupling device is mandatory between them. In photocatalytic microreactors one often uses nanoparticles with localized SPP as both couplers and field enhancers. In this contribution we consider the possibility to utilize surface corrugation of thin gold films to simultaneously ensure coupling between propagating and plasmon modes and enlarge effective catalytic surface. To this purpose we utilize wet chemical etching (chemical micromachining). Different surface corrugations are obtained by varying etching conditions. A combination of gold thin film over corrugated surface and titanium dioxide nanoparticles is used. The setup can be used for different photocatalytic processes

Plasmonic enhancement of photocatalytic optofluidic microreactors with corrugated thin metal films

Plasmonics deals with electromagnetic waves that are bound to an interface between conductor with free electron plasma and dielectric, and are evanescent in the perpendicular directions. This ensures extreme localizations of electromagnetic near fields in subwavelength volumes [1,2].A number of systems where plasmonic activation is used for photocatalysis has been reported until now [3-6]. A vast majority of these relies on localized surface plasmon resonance on nanoparticles, which may have either monolithic [7] or core shell structure [8]. In our experiment we propose the use of disordered rough plasmonic surface for the enhancement of photocatalytic microreactors. The basic idea was to fabricate a microreactor structure with the microchannel bottom surface roughened by wet chemical etching and subsequently covered by a thin gold layer (plasmonic material). Experiments in wet chemical etching was performed on two single crystal, n-type silicon wafers, double side polished, 3" in diameter. Thermal oxide was used as a masking layer on Si wafers. A protective oxide had a thickness value about 0,6 µm for chemical etching in KOH (potassiumhydroxide) and 1 µm for chemical etching in TMAH (tetramethylammonium hydroxide). Thermal oxide was etched in BHF (buffered hydrofluoric acid) from the top side of wafers, after that wafers were cut on 6 pieces, samples. One set of samples was etched in 30 wt.% KOH water solution at 80 °C for 2 min, 4 min, 6 min, 8 min, 10 min, with etching rate of 1,1 µm/min. And the other set of samples was etched in 25 wt.% TMAH water solution at 60 °C for 2 min, 3 min, 4 min, 5 min, 6 min, with etching rate of 0,16 µm/min.All samples were cut in half, and one half of each sample was gold sputtered. As a coupler between propagating and surface modes for plasmonic enhancement of photocatalytic optofluidicmicroreactors thin layer of gold, Au, was used with sublayer of chrome, Cr. Sublayer must be present for purpose of good adhesion of gold on silicon surface. The minimum of thickness value for gold and chrome as sublayer have to be around 20nm, 10 nm respectively. Thickness value of layer and sublayer, combined, must be smaller then value of roughness of silicon surface. The roughness of the surface of the three dimensional images was determined with atomic force microscope TM Microscopes – Veeco in contactless mode. Different surface profiles were obtained by different profiling mechanisms.We obtained better surface with samples which were etched in 30 wt. % KOH water solution. This opens a path toward surface profile tailoring and optimization in the sense of maximizing the coupling efficiency and tuning it to a desired spectral range. The approach can be used in general optofluidics and for lab on chip devices

Monolithically Integrated Diffused Silicon Two-Zone Heaters for Silicon-Pyrex Glass Microreactors for Production of Nanoparticles: Heat Exchange Aspects.

We present the design, simulation, fabrication and characterization of monolithically integrated high resistivity p-type boron-di used silicon two-zone heaters in a model high temperature microreactor intended for nanoparticle fabrication. We used a finite element method for simulations of the heaters’ operation and performance. Our experimental model reactor structure consisted of a silicon wafer anodically bonded to a Pyrex glass wafer with an isotropically etched serpentine microchannels network. We fabricated two separate spiral heaters with di erent temperatures, mutually thermally isolated by barrier apertures etched throughout the silicon wafer. The heaters were characterized by electric measurements and by infrared thermal vision. The obtained results show that our proposed procedure for the heater fabrication is robust, stable and controllable, with a decreased sensitivity to random variations of fabrication process parameters. Compared to metallic or polysilicon heaters typically integrated into microreactors, our approach o ers improved control over heater characteristics through adjustment of the Boron doping level and profile. Our microreactor is intended to produce titanium dioxide nanoparticles, but it could be also used to fabricate nanoparticles in di erent materials as well, with various parameters and geometries. Our method can be generally applied to other high-temperature microsystems

Uhvaćen je stari lisac - stafilokokni toksični šok sindrom kod odraslog muškarca - prikaz slučaja

Staphylococcal toxic shock syndrome (STSS) is typically detected in newborns and children but can be seen in adults occasionally. In such a case, it points out usually on some immune system dysfunction. We present a case of a critically-ill adult male with STSS and symptoms and signs of serious systemic infection (hemodynamic instability, acute renal failure, mental confusion). After the completion of applied treatment (antistaphylococcal antimicrobials, hemodialysis, vasopressor, supportive, and symptomatic therapy), complete restoration of presented patients' derangements was achieved. Timely diagnosis and appropriate treatment is the mainstay in the management of STSS in adults.Stafilokokni toksični šok sindrom (STŠS) se obično javlja kod novorođenčadi i dece, ali se povremeno može javiti i kod odraslih. U tom slučaju, obično ukazuje na disfunkciju imunog sistema. Prikazan je slučaj kritično-obolelog odraslog muškarca sa STŠS i simptomima i znacima životno-ugrožavajuće sistemske infekcije (hemodinamska nestabilnost, akutna insuficijencija bubrega, konfuzija). Nakon završenog lečenja (anti-stafilokoni antibiotici, hemodijaliza, vazopresori, suportivna i simptomatska terapija), postignuta je potpuna remisija kod obolelog. Pravovremena dijagnostika i adekvatan tretman je glavno uporište u lečenju STŠS kod odraslih

Results of the COVID-19 mental health international for the general population (COMET-G) study.

INTRODUCTION: There are few published empirical data on the effects of COVID-19 on mental health, and until now, there is no large international study. MATERIAL AND METHODS: During the COVID-19 pandemic, an online questionnaire gathered data from 55,589 participants from 40 countries (64.85% females aged 35.80 ± 13.61; 34.05% males aged 34.90±13.29 and 1.10% other aged 31.64±13.15). Distress and probable depression were identified with the use of a previously developed cut-off and algorithm respectively. STATISTICAL ANALYSIS: Descriptive statistics were calculated. Chi-square tests, multiple forward stepwise linear regression analyses and Factorial Analysis of Variance (ANOVA) tested relations among variables. RESULTS: Probable depression was detected in 17.80% and distress in 16.71%. A significant percentage reported a deterioration in mental state, family dynamics and everyday lifestyle. Persons with a history of mental disorders had higher rates of current depression (31.82% vs. 13.07%). At least half of participants were accepting (at least to a moderate degree) a non-bizarre conspiracy. The highest Relative Risk (RR) to develop depression was associated with history of Bipolar disorder and self-harm/attempts (RR = 5.88). Suicidality was not increased in persons without a history of any mental disorder. Based on these results a model was developed. CONCLUSIONS: The final model revealed multiple vulnerabilities and an interplay leading from simple anxiety to probable depression and suicidality through distress. This could be of practical utility since many of these factors are modifiable. Future research and interventions should specifically focus on them

PORTFOLIO PERFORMANCE EVALUATION OF MUTUAL FUNDS IN THE REPUBLIC OF SERBIA

© 2020, Serbian Journal of Management. All Rights Reserved The paper evaluates the performance of open-end mutual funds in the Republic of Serbia in the period 2011-2015, using various modelling approaches based on different models. The aim of this paper is to examine the theoretical, methodological and empirical validity of active portfolio management of mutual funds and to assess the presence of selection and timing abilities of Serbian portfolio managers. The results of the empirical research show that the active portfolio management of mutual funds in the Republic of Serbia has not been successful in terms of outperforming the market. Portfolio managers of most Serbian mutual funds lack the ability to choose profitable securities and do not have market timing ability

Dynamic analysis of the efficiency of research and development systems of South-European countries

© 2019 Faculty of Organizational Sciences, Belgrade. All rights reserved. The non-parametric deterministic procedure of Data Envelopment Analysis (DEA) to measure and compare relative efficiency of research and development (R/D) activities in nine South-European countries in the period 2007-2016 is applied in this paper. To that end, we made a corresponding DEA model with nine decision-making units, two inputs and two outputs, selected by correlation analysis. The obtained results, i.e., relative R/D efficiency, were subject to correlation analysis in the context of the achieved average gross domestic product growth rate of the observed decision-making units, which showed that there was no strong correlation between those two variables at the level of the observed national economies