The influence of material types on twist angles and torsion stability of a composite shaft

Prednost primjene kompozitnih materijala, u odnosu na konvencionalne materijale, ogleda se u mogućnosti širokog variranja praktično svih svojstava materijala od kojih su sastavljeni, što se postiže putem izbora sastavnih komponenata, njihove količine, rasporeda i orijentacije u okviru materijala, a s ciljem da se iskoriste njihova najbolja svojstva. U nekim slučajevima najbolji rezultati mogu biti postignuti uporabom kombinacije kompozita i tradicionalnih metalnih materijala. U radu su analizirana vratila dobivena kombinacijom aluminija s različitim kompozitnim materijalima – karbonska vlakna/epoksi smola, staklena vlakna/epoksi smola, aramidna vlakna/epoksi smola. Razmatran je njihov utjecaj na vrijednosti kutova uvijanja i kritične vrijednosti momenta uvijanja koje dovode do gubitka stabilnosti vratila. Provedena je i eksperimentalna analiza vratila koje je pokazalo najbolja svojstva (karbonska vlakna/epoksi smola).The advantages of composite materials over the conventional ones include the ability to vary their properties in order to ensure the best combination for each application. This is achieved through selection of their constituent materials, quantities, distribution and fibre orientation angle. In some cases, the best results can be achieved by using a combination of composite and traditional metal materials. This paper analyses shafts made from a combination of aluminium and different composite materials – carbon fibre/epoxy, glass fibre/epoxy, and aramid fibre/epoxy. The influence of these materials on twist angle values and critical torques that impair the shaft stability has also been discussed. Finally, an experimental analysis of the shaft that exhibited the best properties (carbon fibres/epoxy) has been performed

Effect of aspartame on biochemical and oxidative stress parameters in rat blood

Aspartame (ASP) is one of the most widely used nonnutritive sweeteners. This study investigates the chronic effects of ASP on hematological and biochemical parameters, and its effects on the oxidative/antioxidative status in the red blood cells of Wistar albino rats. Rats were provided with ASP (40 mg/kg/daily for six weeks) in drinking water. Increased food and fluid intake was observed in the ASP-treated rats. Total body mass was significantly decreased in the ASP-treated rats. Treatment with ASP caused an increase in the concentrations of glucose, cholesterol, LDL-cholesterol, and in the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH), as well as a decrease in the levels of HDL-cholesterol in the serum. A significant decline in the number of white blood cells (WBC) was observed after ASP uptake. Based on the results we conclude that ASP induces oxidative stress, observed as an alteration of the glutathione redox status, which leads to increased concentrations of nitric oxide (NO) and lipid peroxides (LPO) in the red blood cells. Changes in biochemical parameters, lipid metabolism, as well as changes in the levels of oxidative stress markers and the appearance of signs of liver damage indicate that chronic use of ASP can lead to the development of hyperglycemia, hypercholesterolemia and associated diseases

The Role of Persistent Organic Pollutants in Obesity: A Review of Laboratory and Epidemiological Studies

Persistent organic pollutants (POPs) are considered as potential obesogens that may affect adipose tissue development and functioning, thus promoting obesity. However, various POPs may have different mechanisms of action. The objective of the present review is to discuss the key mechanisms linking exposure to POPs to adipose tissue dysfunction and obesity. Laboratory data clearly demonstrate that the mechanisms associated with the interference of exposure to POPs with obesity include: (a) dysregulation of adipogenesis regulators (PPARγ and C/EBPα); (b) affinity and binding to nuclear receptors; (c) epigenetic effects; and/or (d) proinflammatory activity. Although in vivo data are generally corroborative of the in vitro results, studies in living organisms have shown that the impact of POPs on adipogenesis is affected by biological factors such as sex, age, and period of exposure. Epidemiological data demonstrate a significant association between exposure to POPs and obesity and obesity-associated metabolic disturbances (e.g., type 2 diabetes mellitus and metabolic syndrome), although the existing data are considered insufficient. In conclusion, both laboratory and epidemiological data underline the significant role of POPs as environmental obesogens. However, further studies are required to better characterize both the mechanisms and the dose/concentration-response effects of exposure to POPs in the development of obesity and other metabolic diseases.publishedVersio

DEFICIT IRRIGATION TECHNIQUE FOR REDUCING WATER USE OF TOMATO UNDER POLYTUNNEL CONDITIONS

The aim of paper was to asses the use of regulated deficit irrigation (RDI) for production of two tomato cultivars (Cedrico and Abellus) in polytunnels in Serbia. RDI plants received 60% of the water that was applied to FI plants and significant saving of water for irrigation and increased in irrigation water use efficiency (IWUE) were achieved. Yield data for Cedrico cultivar showed no differences between RDI and FI, while due to the bigger sensitivity to drought, yield of Abellus was reduced under RDI. In general, fruit quality (soluble solids, titrable acidity) was sustained or improved in both cultivars under RDI. Economic analyses showed that due to the current low prices of water and electricity in Serbia, the profit increase of Cedrico, similarly to the previously trialed cultivar Amati, was not high under RDI comparing to FI. Reduction of yield and consequent profit for Abellus, indicated that for future commercial growing of tomato under RDI should be used drought resistant cultivars

Different levels of humoral immunoreactivity to different wheat cultivars gliadin are present in patients with celiac disease and in patients with multiple myeloma

<p>Abstract</p> <p>Background</p> <p>Immunity to food antigens (gliadin, cow's milk proteins) is in the centre of the attention of modern medicine focused on the prevention of diseases, prevention which is based on the use of appropriate restriction diet. Detection of the enhanced levels of the immune reactions to antigen(s) present in food is from this point of view of great importance because there are reports that some of health disturbances, like celiac disease (CD) and some premalignant conditions, like monoclonal gammopathy of undetermined significance (MGUS), were vanished after the appropriate restriction diets.</p> <p>It is well known that gliadin is toxic to small bowel mucosa of relatively small population of genetically predisposed individuals, who under this toxic action develop celiac disease (CD). As the quantity of immunogenic gliadin could vary between different wheat species, the first aim of this work was to determine the percentage of immunogenic gliadin in ten bread wheat cultivars and in three commercially grown durum wheat cultivars. The second part of the study was initiated by results of previous publication, reporting that sera of some of multiple myeloma (MM) patients showed the presence of elevated levels of anti-gliadin IgA, without the enhanced levels of anti-gliadin IgG antibodies, determined with commercial ELISA test. It was designed to assess is it possible to reveal is there any hidden, especially anti-gliadin IgG immunoreactivity, in serum of mentioned group of patients. For this purpose we tested MM patients sera, as well as celiac disease (CD) patients sera for the immunoreaction with the native gliadin isolated from wheat species used for bread and pasta making in corresponding geographic region.</p> <p>Results</p> <p>Gliadin was isolated from wheat flour by two step 60% ehanolic extraction. Its content was determined by commercial R5 Mendez Elisa using PWG gliadin as the standard. Results obtained showed that immunogenic gliadin content varies between 50.4 and 65.4 mg/g in bread wheat cultivars and between 20 and 25.6 mg/g in durum wheat cultivars.</p> <p>Anti-gliadin IgA and IgG immunoreactivity of patients' sera in (IU/ml) was firstly determined by commercial diagnostic Binding Site ELISA test, and then additionally by non-commercial ELISA tests, using standardized ethanol wheat extracts -gliadin as the antigen.</p> <p>In both patients groups IgA immunoreactivity to gliadin from different cultivars was almost homogenous and in correlation with results from commercial test (except for one patient with IgA(λ) myeloma, they were more then five times higher). But, results for IgG immunoreactivity were more frequently inhomogeneous, and especially for few MM patients, they were more then five times higher and did not correlate with results obtained using Binding Site test.</p> <p>Conclusion</p> <p>Results obtained showed different content of immunogenic gliadin epitopes in various species of wheat.</p> <p>They also point for new effort to elucidate is there a need to develop new standard antigen, the representative mixture of gliadin isolated from local wheat species used for bread production in corresponding geographic region for ELISA diagnostic tests.</p

Nickel as a potential disruptor of thyroid function: benchmark modelling of human data

IntroductionNickel (Ni) is one of the well-known toxic metals found in the environment. However, its influence on thyroid function is not explored enough. Hence, the aim of this study was to analyse the potential of Ni to disrupt thyroid function by exploring the relationship between blood Ni concentration and serum hormone levels (TSH, T4, T3, fT4 and fT3), as well as the parameters of thyroid homeostasis (SPINA-GT and SPINA-GD) by using correlation analysis and Benchmark (BMD) concept.MethodsNi concentration was measured by ICP-MS method, while CLIA was used for serum hormone determination. SPINA Thyr software was used to calculate SPINA-GT and SPINA-GD parameters. BMD analysis was performed by PROAST software (70.1). The limitations of this study are the small sample size and the uneven distribution of healthy and unhealthy subjects, limited confounding factors, as well as the age of the subjects that could have influenced the obtained results.Results and discussionThe highest median value for blood Ni concentration was observed for the male population and amounted 8,278 µg/L. Accordingly, the statistically significant correlation was observed only in the male population, for Ni-fT4 and Ni-SPINA-GT pairs. The existence of a dose-response relationship was established between Ni and all the measured parameters of thyroid functions in entire population and in both sexes. However, the narrowest BMD intervals were obtained only in men, for Ni - SPINA-GT pair (1.36-60.9 µg/L) and Ni - fT3 pair (0.397-66.8 µg/L), indicating that even 78.68 and 83.25% of men in our study might be in 10% higher risk of Ni-induced SPINA-GT and fT3 alterations, respectively. Due to the relationship established between Ni and the SPINA-GT parameter, it can be concluded that Ni has an influence on the secretory function of the thyroid gland in men. Although the further research is required, these findings suggest possible role of Ni in thyroid function disturbances

The Effects of Magnesium – Melatonin - Vit B Complex Supplementation in Treatment of Insomnia

Insomnia means difficulty in falling asleep and/or stays asleep. Insomnia commonly leads to daytime sleepiness, lethargy, and a general feeling of being unwell. The most common treatment of insomnia includes GABAA receptor positive allosteric modulators or Melatonin agonists. Our study aimed to evaluate the efficacy of Magnesium- melatonin-vitamin B complex supplement in the treatment of insomnia. The study included 60 patients diagnosed with insomnia. The patients were randomly divided into study group (N = 30), and control group (N = 30), and study group was treated with Magnesium-melatonin-vitamin B complex (one dose contains 175 mg liposomal magnesium oxide, 10 mg Vit B6, 16 μg vit B12, melatonin 1 mg, Extrafolate-S 600 μg) once a day 1 hour before sleep, during the 3 months. The severity of insomnia symptoms was measured by self-reported Athens insomnia scale (AIS), with a cut-off score by Soldatos (AIS score ≥ 6). Mean AIS score at zero points was 14,93 ± 3,778 in the study group and 14,37 ± 4,081 in the control group (p = 0,476), indicating the compatibility of the groups, and both scores correspond to mild to moderate insomnia. Mean AIS score after 3 months of the Magnesium- melatonin- vitamin B complex supplementation was 10,50 ± 4,21 corresponding to mild insomnia, while median AIS score in the control group was 15,13 ± 3,76 which is referred to moderate insomnia, and difference among groups was significant (p = 0,000). Our founding’s indicating that 3 months of the Magnesium- melatonin-vitamin B complex supplementation has a beneficial effect in the treatment of insomnia regardless of cause

Three lines of evidence of the hepatotoxicity young researchers of a mixture containing phthalates and bisphenol a: in silico and two in vivo models

The extensive usage of bis(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), and bisphenol A (BPA) creates a lot of opportunities for combined human exposure to these hazardous compounds in everyday life and a variety of negative outcomes, including hepatotoxicity. In silico research and two in vivo models were used to investigate the links between a mixture including DEHP, DBP and BPA and liver injury. Bioinformatic analysis was performed by Comparative Toxicogenomics Database, ShinyGO, ToppCluster, and Cytoscape. In vivo subacute study included five groups of rats (n = 6): (1) Control: corn oil, (2) DEHP: 50 mg/kg b.w./day, (3) DBP: 50 mg/kg b.w./day, (4) BPA: 25 mg/kg b.w./day, (5) MIX: DEHP + DBP + BPA. Zebrafish embryos were exposed to the investigated substances in multiple dosages, both alone and in combination (binary and ternary mixtures). Liver damage was linked to 75 DEHP, DBP, and BPA genes, the majority of which were associated with inflammation/oxidative stress, identified as the most relevant molecular pathways. In rats, significant changes in redox status/bioelements’ level and pathohistology were more pronounced or evident only in MIX group, suggesting probable additivity. In a dose-dependent manner, BPA reduced the liver area (LA) index. LA values were decreased by DEHP (2 μg/mL) and DBP (5 μg/mL), whereas LA index was raised by their higher concentrations. In binary mixtures, DBP had a lethal effect at the two highest concentrations, whereas BPA directed hepatotoxicity of the DEHP/DBP/BPA mixture

Comparison of exercise, dobutamine-atropine and dipyridamole-atropine stress echocardiography in detecting coronary artery disease

BACKGROUND: Dipyridamole and dobutamine stress echocardiography testing are most widely utilized, but their sensitivity remained suboptimal in comparison to routine exercise stress echocardiography. The aim of our study is to compare, head-to-head, exercise, dobutamine and dipyridamole stress echocardiography tests, performed with state-of-the-art protocols in a large scale prospective group of patients. METHODS: Dipyridamole-atropine (Dipatro: 0.84 mg/kg over 10 min i.v. dipyridamole with addition of up to 1 mg of atropine), dobutamine-atropine (Dobatro: up to 40 mcg/kg/min i.v. dobutamine with addition of up to 1 mg of atropine) and exercise (Ex, Bruce) were performed in 166 pts. Of them, 117 pts without resting wall motion abnormalities were enrolled in study (91 male; mean age 54 ± 10 years; previous non-transmural myocardial infarction in 32 pts, angina pectoris in 69 pts and atypical chest pain in 16 pts). Tests were performed in random sequence, in 3 different days, within 5 day period under identical therapy. All patients underwent coronary angiography. RESULTS: Significant coronary artery disease (CAD; ≥50% diameter stenosis) was present in 69 pts (57 pts 1-vessel CAD, 12 multivessel CAD) and absent in 48 pts. Sensitivity (Sn) was 96%, 93% and 90%, whereas specificity (Sp) was 92%, 92% and 87% for Dobatro, Dipatro and Ex, respectively (p = ns). Concomitant beta blocker therapy did not influence peak rate-pressure product and Sn of Dobatro and Dipatro (p = ns). CONCLUSION: When state-of-the-art protocols are used, dipyridamole and dobutamine stress echocardiography have comparable and high diagnostic accuracy, similar to maximal post-exercise treadmill stress echocardiography

Low-dose adenosine stress echocardiography: Detection of myocardial viability

OBJECTIVE: The aim of this study was to evaluate the diagnostic potential of low-dose adenosine stress echocardiography in detection of myocardial viability. BACKGROUND: Vasodilation through low dose dipyridamole infusion may recruit contractile reserve by increasing coronary flow or by increasing levels of endogenous adenosine. METHODS: Forty-three patients with resting dyssynergy, due to previous myocardial infarction, underwent low-dose adenosine (80, 100, 110 mcg/kg/min in 3 minutes intervals) echocardiography test. Gold standard for myocardial viability was improvement in systolic thickening of dyssinergic segments of ≥ 1 grade at follow-up. Coronary angiography was done in 41 pts. Twenty-seven patients were revascularized and 16 were medically treated. Echocardiographic follow up data (12 ± 2 months) were available in 24 revascularized patients. RESULTS: Wall motion score index improved from rest 1.55 ± 0.30 to 1.33 ± 0.26 at low-dose adenosine (p < 0.001). Of the 257 segments with baseline dyssynergy, adenosine echocardiography identified 122 segments as positive for viability, and 135 as necrotic since no improvement of systolic thickening was observed. Follow-up wall motion score index was 1.31 ± 0.30 (p < 0.001 vs. rest). The sensitivity of adenosine echo test for identification of viable segments was 87%, while specificity was 95%, and diagnostic accuracy 90%. Positive and negative predictive values were 97% and 80%, respectively. CONCLUSION: Low-dose adenosine stress echocardiography test has high diagnostic potential for detection of myocardial viability in the group of patients with left ventricle dysfunction due to previous myocardial infarction. Low dose adenosine stress echocardiography may be adequate alternative to low-dose dobutamine test for evaluation of myocardial viability