83 research outputs found
Utjecaj izloženosti 1,6-heksametilen diizocijanatu (HDI) na vršni ekspiratorni protok u autolakirera u Iranu
Get PDFThe aim of this study was to investigate the effects of occupational exposure to 1,6-hexamethylene diisocyanate (HDI) on peak flowmetry in automobile body paint shop workers in Iran. We studied a population of 43 car painters exposed to HDI at their workplaces. Peak expiratory fl ow was tested for one working week, from the start to the end of each shift. Air was sampled and HDI analysed in parallel, according to the OSHA 42 method. Daily and weekly HDI exposure averages were (0.42±0.1) mg m-3 and (0.13±0.05) mg m-3, respectively. On painting days, 72 % of workers showed more than a 10 % variation in peak expiratory fl ow. Inhalation exposure exceeded the threshold limit value (TLV) ten times over. This strongly suggests that HDI affected the peak fl owmetry in the studied workers.Cilj je ovog ispitivanja bio utvrditi vršni protok u 43 iranska autolakirera profesionalno izložena 1,6-heksametilen diizocijanatu (HDI). Vršni ekspiratorni protok testiran je tjedan dana na početku i kraju svake smjene. Uzorkovanje i mjerenje HDI-ja u zraku radilo se istodobno s testiranjem vršnoga protoka, prema metodi OSHA 42.
Prosječna dnevna izloženost radnika HDI-ju iznosila je (0.42±0.1) mg m-3, a tjedna (0.13±0.05) mg m-3. U 72 % radnika vršni ekspiratorni protok tijekom dana varirao je više od 10 %.
Radnici su udisali deset puta više razine HDI-ja od graničnih te je moguće da je HDI utjecao na mjerenja plućne funkcije
Slip-Flow and Heat Transfer of a Non-Newtonian Nanofluid in a Microtube
Get PDFThe slip-flow and heat transfer of a non-Newtonian nanofluid in a microtube is theoretically studied. The power-law rheology is adopted to describe the non-Newtonian characteristics of the flow, in which the fluid consistency coefficient and the flow behavior index depend on the nanoparticle volume fraction. The velocity profile, volumetric flow rate and local Nusselt number are calculated for different values of nanoparticle volume fraction and slip length. The results show that the influence of nanoparticle volume fraction on the flow of the nanofluid depends on the pressure gradient, which is quite different from that of the Newtonian nanofluid. Increase of the nanoparticle volume fraction has the effect to impede the flow at a small pressure gradient, but it changes to facilitate the flow when the pressure gradient is large enough. This remarkable phenomenon is observed when the tube radius shrinks to micrometer scale. On the other hand, we find that increase of the slip length always results in larger flow rate of the nanofluid. Furthermore, the heat transfer rate of the nanofluid in the microtube can be enhanced due to the non-Newtonian rheology and slip boundary effects. The thermally fully developed heat transfer rate under constant wall temperature and constant heat flux boundary conditions is also compared
Effect of pentoxifylline on preventing acute kidney injury after cardiac surgery by measuring urinary neutrophil gelatinase - associated lipocalin
Get PDFOcjena i usporedba respiratornih simptoma i kapaciteta pluća u radnika tvornice keramičkih pločica iz Yazda u Iranu
Get PDFTile workers are exposed to dust particles and are susceptible to multiple pulmonary complications. Problems like asthma, chronic obstructive pulmonary symptoms, and silicosis are more common among them. As there are many tile factories in Yazd, we decided to evaluate the respiratory symptoms and lung capacities in these workers and compare them with controls. This study included 176 tile and ceramic factory workers occupationally exposed to dust and 115 unexposed workers as controls. We recorded the respiratory symptoms using the British Medical Research Council questionnaire and measured lung capacities of the two groups. All study subjects were male, and the two groups were comparable in age and smoking. The exposed group had frequent respiratory symptoms and a significant relationship between them and duration of employment. In addition, lung capacities in ceramic workers with symptoms were lower than in workers without the symptoms. Even though the respiratory symptoms were more frequent in the exposed group than in controls, lung capacities of the two groups were similar.Radnici u proizvodnji keramičkih pločica izloženi su česticama prašine te su skloni višestrukim plućnim komplikacijama. U njih je veća učestalost tegoba poput astme i simptoma kronične opstruktivne bolesti pluća te silikoze. Budući da u Yazdu ima mnogo tvornica keramike, odlučili smo upravo u tome gradu ocijeniti respiratorne simptome i izmjeriti kapacitet pluća njihovih radnika i usporediti ih s kontrolnom skupinom. Ispitivanje je stoga obuhvatilo 176 radnika u proizvodnji keramičkih pločica izloženih prašini te 115 neizloženih radnika koji su činili kontrolnu skupinu. Respiratorni su se simptomi ispitali rabeći upitnik Britanskoga savjeta za medicinska istraživanja (British Medical Research Council), a u obje je skupine izmjeren kapacitet pluća. Svi su ispitanici bili muškarci, a skupine su se podudarale po dobi i pušenju. Respiratorni simptomi bili su česti u izloženoj skupini te je u njoj uočena značajna povezanost između respiratornih simptoma i radnoga staža u tvornici. Usto su izloženi radnici s respiratornim simptomima iskazali slabije kapacitete pluća od radnika bez simptoma. Ovi su respiratorni simptomi bili češći u izloženoj skupini negoli u kontrolnoj, ali se njihovi kapaciteti pluća nisu bitno razlikovali
Pentoxifylline reduces the inflammatory process in diabetic rats: relationship with decreases of pro-inflammatory cytokines and inducible nitric oxide synthase
Get PDFSemen quality characteristics of Koekoek breeder cocks influenced by supplemental inclusion levels of onion and garlic mixture at 35-41 weeks of age
Full text linkJob Stress in Shift Workers and Non-Shift Workers of One of Yazd Dairy Industries
No full textIntroduction: Many industries need to work all day long and present full-time services. Therefore, individuals and organizations are exposed to new issues like shift work. The necessity of attention to work environment and worker’s health and job stress provoked us to conduct this study to investigate the relationship between job stress and shift work.
Methods: In a descriptive and survey study, we investigated job stress of 100 workers of an industry, selected randomly, using job stress and personal-occupational information questionnaires. To test the research hypotheses, we used correlation, t-test and multi-variables regression.
Results: The results showed that job stress is higher in shift workers than non-shift workers. Furthermore, a significant relationship was observed between the amount (α=0.01, F=8.99) and source (α=0.05, F=3.76) of stress and demographic variables as well as between the worker’s stress and their level of education. Moreover, this research indicated that it is possible to predict stress from demographic variables (α=0.05, F=0.35) and there is a positive significant correlation between the amount (r=0.78) and source (r=0.54) of stress and shift work.
Conclusion: we can conclude that there is a significant relationship between job stress and shift work. So, such studies are suggested the results of which are used to achieve operational solutions and job design interventions related to type of work and ergonomics of work environment to improve worker’s health and job stress
USE OF GLASS FIBER POLYMERS (GFRPS) FOR STRENGTHENING OF SEMI-SUPPORTED STEEL SHEAR WALL
No full textDuring the recent past decade, semi-supported steel shear walls (SSSW) have been introduced as an alternative to the traditional type of steel plate shear walls (SPSW). In this system, the shear wall does not connect directly to the main columns of the building frame; instead, it is connected to a pair of secondary columns that do not carry gravity loads. However, a SSSW system,
compared to the corresponding SPSW system in which the infill plate is connected to the main frame columns, has a lower span width (or lower infill plate width) and, thus, lower strength, stiffness and energy dissipation capability. To offset these effects, one effective and practical approach is the use of fiber-reinforced-polymers (GFRPs) for strengthening the steel infill plate. GFRP laminates can be easily attached to one or both sides of the infill plates by the use of adhesive. In this paper, the behavior of semi-supported steel shear walls reinforced by glass-fiber-reinforced-polymers (GFRPs) is studied using the finite-element method and compared with the corresponding systems without the reinforcement. A number of semi-supported steel shear walls with different plate aspect ratios, plate thicknesses, secondary column profiles, and with and without opening of various sizes is considered for this research. Both pushover and cyclic analyses are performed. The adequacy of the finite-element modeling approach for representing the pushover and cyclic responses of SPSWs is verified through comparisons with experimental results. Results show that the use of GFRP laminates, especially for the system with thinner infill plate thickness, can significantly increase the system strength, initial stiffness, and energy dissipation, while it partially decreases the system ductility. In turn, the improvement of the system strength and energy dissipation capability is mainly due to the improvement of the SSSW infill plate behavior. In fact, the use of GFRP laminates does not affect much the hysteresis and pushover behavior of the SSSW frames
Effect of L-carnitine administration on serum insulin and adiponectin levels, and AMPK, APPL1 and PPARγ gene expression in STZ-induced diabetic rat liver
No full textDiabetes is considered as a metabolic disease in which insulin secretion and functions are disturbed and characterized by hyperglycemia. L-carnitine is synthesized in most mammals and plays critical role in fatty acid oxidation and energy production. Data about the L-carnitine hypoglycemic effects are controversial. We evaluated long-term oral L-carnitine administration effects on blood glucose, insulin and adiponectin levels, as well as expression of AMPK, APPL1 and PPARγ genes in liver of STZ-induced diabetic rats. Group 1 (control), did not receive any treatment, group 2 received 50 mg/kg STZ by i.p injection, group 3 received single dose of 50 mg/kg STZ by i.p injection and also 600 mg/kg/day L-carnitine orally for 5 weeks. Our results showed that L-carnitine long-term oral supplementation significantly reduced blood glucose and normalized insulin levels in diabetic rats. Also, we found that L-carnitine significantly increased AMPK and APPL1 expression, and showed a mild elevation of PPARγ expression. In sum, we suggest that long-term L-carnitine supplementation has beneficial effects on diabetic rats which showed hypoglycemic effects. Probably the beneficial effects of L-carnitine are contributed to the upregulation of insulin sensitizers such as AMPK and adiponectin
The Cytotoxic Effects of Sio2 Nanoparticles on Human Blood Mononuclear Cells
No full textIntroduction: Regarding the increasing use of silicon dioxide nanoparticles in medical biotechnology and probable side effects and diseases resulting from its usage, this study was performed to assess the toxic effects of different concentrations of SiO2 nanoparticles on human blood mononuclear leukocytes using the MTT assay. Methods: In this laboratory trial study, we prepared suspensions of blood mononuclear cells from 10 young healthy men and also different concentrations of the nanoparticles (1, 10, 100, 500, 1000 and 1500µg/mL). The cells were then incubated with these nanoparticles for 24 hours at 37 °c, and finally the percent of dead cells were measured by MTT assay kit using spectrophotometer reading at 490 nm after 6 and 24 hours of incubation. Positive and negative controls and blanking were applied, too. Results: A significant difference was found in percent of dead cells between the different concentrations of SiO2 nanoparticles and also between the exposed cells and control group (p<0.05). There was increasing cytotoxicity in 6 hours as well as 24 hours exposure with higher concentrations of the nanoparticles. Cytotoxicity after 24 hours exposure to 10 µg/mL of nanoparticles was about 6 times that of the 1 µg/mL. Conclusion: This study showed for the first time that SiO2 with a concentration of 1 µg/mL has cytotoxicity on human blood mononuclear cells. Cytotoxic effects of this nanoparticle are time- and concentration-dependent
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