Fracture mechanics analysis of damaged turbine rotor discs using finite element method

This paper presents evaluation fracture mechanics parameters in low pressure turbine components. Critical locations such as keyway and dovetail area are experiencing stress concentration leading to crack initiation. Stress intensity factors were evaluated using the J-Integral approach available within ANSYS software code. The finite element method allowed the prediction of the point of crack initiation and the crack propagation using the orientations of the maximum principal stresses. Special attention in this investigation is focused to develop analytic expressions for stress intensity factors at critical location of low pres-sure steam turbine disc. [Projekat Ministarstva nauke Republike Srbije, br. I-174001 i br. TR-35045

GENDER DIFFERENCES IN ACADEMIC STRESS AND BURNOUT AMONG MEDICAL STUDENTS IN FINAL YEARS OF EDUCATION

Background: The educational process brings a considerable amount of stress to medical students that can influence mental health status and contribute to further professional burnout. The authors assessed the academic stress influences, mental health status and burnout syndrome, with the intent to find different patterns in female and male medical students. Subjects and methods: The applied cross sectional study was in the form of an anonymous questionnaire which included: sociodemographic data, self-reported health status and influence of studying activities on stress level in 755 medical students who attended two final years. Mental health status was explored by the General Health Questionnaire (GHQ-12), and Maslach Burnout Inventory (MBI). Results: Female students assessed their physical health status and general stress level as worse compared to males (p<0.001). Exams were described as a high stressor in about 50% of all examined students. However, this stressor was significantly more frequent in female students (p<0.001). Female students frequently declared high stressful effects of contacts with patients (p=0.009) and autopsy (p<0.001). The scores of the GHQ-12 questionnaire were above the threshold or high in 51.5% of all students, and also significantly higher in females (p=0.001). High scores were found among 52.6% of all examined students on MBI subscale of Depersonalization, and 33.6% on MBI subscale of Emotional exhaustion without gender difference. Conclusion: Measures for prevention of academic distress should be targeted at optimization of the educational process, development of the clinical skills and professionalism, with special concern to female students who manifested high vulnerability

ELECTRODEPOSITION AND MORPHOLOGY OF COPPER POWDER PARTICLES OBTAINED AT DIFFERENT CURRENT REGIMES

The effect different deposition regimes (constant and reversing currents), on the powdered copper electrodeposits morphology were investigated. The morphology of electrodeposited copper powder was investigated using a scanning electron microscope (SEM). The effect of the current amplitude, cathodic to anodic time ratio and period of the current wave are discussed. It is shown that the parameters determining the reversing current wave determine the micro-morphology of the copper powder particles deposited

The content of antioxidants in sunflower seed and kernel

The primary objective of this research was to determine differences among investigated sunflower genotypes and whether the analyzed hybrids could be sources of phenols and tocopherols important for storage stability of sunflower seeds and their derived products. DPPH• radical scavenging activity, the content of phenolic components and tocopherols (α-, β-, γ-, and δ-) in seeds and kernels of three sunflower hybrids were analyzed. In the present study, six different phenolic compounds were separated by the HPLC analysis. Chlorogenic acid was the most abundant phenol. The chlorogenic acid content strongly correlated with total phenols (r=0.93). Other marked phenolics were caffeic acid, ferulic acid, rosmarinic acid, myricetin and rutin. The total tocopherols were significantly higher (P lt 0.05) in kernels than in seeds of all sunflower hybrids. Concentrations in sunflower seeds ranged from 200.67 to 220.05 μg/g and from 256.62 to 267.49 μg/g in sunflower kernels where α-tocopherol was the dominant isomer in all samples. The α-tocopherol content was 98% of averaged of the total tocopherols in all analysed samples. All these nutrients with antioxidant properties influenced the capacity of DPPH• scavenging. Accordingly, sunflower kernels had a higher DPPH• scavenging activity, and a higher nutritive value than sunflower seeds

Short-term liquid storage of ram semen in various extenders

The aim of this study was to investigate the effects of three extenders on ram sperm quality after short-term liquid storage (24 hours’ holding time). The study included 20 crossbred rams (Pirot Pramenka x Wurttemberg x Ile de France), 12 months old. Animals were housed at the experimental sheep farm of the Institute for Animal Husbandry in Belgrade, Serbia. Semen was collected through electro ejaculation. The ejaculates were obtained from single services and routine field analysis of the semen was performed immediately after the collection. The semen was split and diluted with three extenders, namely Optidyl®, Andromed® and ultrahigh temperature processed (UHT) milk, in ratios of 1 : 50 or 1 : 100. The ejaculates were examined for sperm motility variables (sperm cell motility percentage, the progressive motility percentage, curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), sperm linearity (LIN), straightness (STR), amplitude of lateral sperm head displacement (ALH), beat cross frequency (BCF) and circular tracks), and sperm morphology (live sperm percentage, percentage of normal sperm forms with intact acrosome, percentage of abnormal sperm forms and total damaged acrosome) by computer-assisted sperm analysis (CASA) and classic sperm cytology after supravital eosin/nigrosine/trypan blue staining, respectively. It was observed that the type of extender used in diluting ram semen is an important factor in the successful short-term liquid preservation (at 4 °C) of ram spermatozoa. In conclusion, this study showed that egg yolk (Optidyl) and soybean (Andromed)-based extenders gave better results of both sperm morphology and sperm motility parameters compared with UHT milk.Keywords: Diluents, morphology, motility, sper

Detekcija i genotipizacija izolata virusa klasične kuge svinja u Srbiji

Classical swine fever (CSF) is a highly contagious disease of pigs leading to significant economic losses worldwide. Classical swine fever virus can be classified into three genogroups, each consisting of three or four subgroups. However, there is a lack of knowledge on the genotypes of CSFV isolates in Republic of Serbia. This study, based on the sequences analysis of partial E2 gene and 5' non coding region (NCR) of 15 CSFV isolated during 2006-2008 from domestic pigs, revealed that all were clustered into genetic group 2.3. Additionally, we showed that the two most often used real time RT-PCR assays were able to detect all local CSF viruses circulated in Serbia in the last years during intensive vaccination campaign against CSF.Klasična kuga svinja (CSF) je visoko kontagiozno oboljenje svinja koje dovodi do značajnih ekonomskih gubitaka širom sveta. Na osnovu genetske strukture, virus klasicne kuge svinja podeljen je utri genogrupe, od kojih svaka ima tri ili četiri podgrupe. Nedostaju podaci o tome koji genotipovi virusa klasične kuge svinja na teritoriji Republike Srbije cirkulišu u prijemčivoj populaciji. Sekvencioniranjem dela E2 gena i 5’nekodirajućeg regiona (NCR) 15 izolata virusa klasične kuge svinja prikupljenih u periodu od 2006-2008 godine, poreklom od domaćih svinja, dokazano je da svi pripadaju genetskoj grupi 2.3. Uz to, dokazano je i da je upotrebom dva najčešće korišćena real time RT-PCR protokola moguće detektovati sve lokalne izolate virusa klasične kuge svinja koji cirkulišu u Srbiji poslednjih godina, u kojoj se uporedo vršila i intenzivna vakcinacija protiv ove bolesti

Occupational exposure to blood and body fluids among health-care workers in Serbia

© 2014 S. Karger AG, Basel. Objectives: The aim of this study was to examine the epidemiology of occupational accidents and self-reported attitude of health-care workers (HCWs) in Serbia. Subjects and Methods: A cross-sectional study was conducted among HCWs in selected departments of five tertiary care hospitals and in one secondary care hospital in February 2012. A previously developed self-administered questionnaire was provided to HCWs who had direct daily contact with patients. χ2 test and Student's t test were used for statistical analysis of the data. Results: Of the 1,441 potential participants, 983 (68.2%) completed the questionnaire: 655 (66.7%) were nurses/medical technicians, 243 (24.7%) were physicians and 85 (8.6%) were other personnel. Of the 983 participants, 291 (29.6%) HCWs had had at least one accident during the previous year and 106 (40.2%) of them reported it to the responsible person. The highest prevalence (68.6%) of accidents was among nurses/technicians (p = 0.001). Accidents occurred more often in large clinical centers (81.1%; p < 0.001) and in the clinical ward, intensive care unit and operating theater (p = 0.003) than in other departments. Seventy-six (13.1%) nurses/medical technicians had an accident during needle recapping (p < 0.001). Of all the HCWs, 550 (55.9%) were fully vaccinated, including significantly more doctors (154, 63.4%) than participants from other job categories (p < 0.001). Conclusion: There was a relatively high rate of accidents among HCWs in our hospitals, most commonly amongst nurses and staff working in clinical wards, intensive care units and operating theaters. The most common types of accidents were needlestick injuries and accidents due to improper handling of contaminated sharp devices or occuring while cleaning instruments or by coming into contact with blood through damaged skin or through the conjunctiva/mucous membranes

Effect of low temperature on rooting rate and carbohydrate content of Fritillaria meleagris bulbs formed in culture in vitro

Projekat ministarstva br. 143026

Djelovanje mono-kvaternernih i bis-kvaternernih piridinijumskih oksima na akutnu toksičnost i antiholinesterazno djelovanje karbarila, dioksakarba i karbofurana

The acute toxicities of insecticidal carbamates (Dioxacarb, Carbaryl and Carbofuran) were determined in mice by s. c. or i. p. injection, both in the absence and in the presence of atropine and several pyridinium oximes. Atropine had a beneficial effect on the toxicity of all the three carbamates, while the oximes varied in their effects. In the case of Carbaryl all oximes used increased its toxicity, while in Dioxacarb and Carbofuran poisoning some of them were effective. It was found that the oximes do not influence the action of carbamates on the activity of serum cholinesterase in vitro, in a way which could explain their effect on the toxicity of these compounds. It is concluded, that the use of oximes is contraindicated in cases of intoxication with Carbaryl, Dioxacarb and Carbofuran.Ispitana je akutna toksičnost karbamatnih insekticida dioksarba, karbarila i karbofurana (LD-50) s. c. ili i. p., sa simultanom primjenom atropina ili bez nje i nekoliko piridinijumskih oksima. Atropin je pokazao povoljan efekat u trovanjima sa sva tri karbamata, dok je djelovanje oksima bilo različito. U trovanjima karbarilom i karbofuranom gotovo svi oksimi su potencirali njihovo toksično djelovanje, dok su u trovanju dioksakarbom neki bili djelotvorni. Oksimi ne utiču na inhibiciju holinesteraze in vitro ovim karbamatima na način kojim bi se moglo rastumačiti njihovo in vivo djelovanje. Na temelju eksperimenata je zaključena da je upotreba oksima u trovanju karbarilom, dioksakarbom i karbofuranom kontraindikovana