178 research outputs found

    Nonisocyanate based polyurethane/silica nanocomposites and their coating performance

    Get PDF
    A series of silica nano-particles with different size were prepared by sol–gel technique, then surface modification by using cyclic carbonate functional organoalkoxysilane (CPS) was performed. Various amounts of carbonated silica particles directly added into carbonated soybean oil (CSBO) and carbonated polypropylene glycol (CPPG) resin mixture to prepare polyurethane–silica nanocomposite coating compositions by nonisocyanate route using an aliphatic diamine as a curing agent. Cupping, gloss, impact, and taber abrasion tests were performed on aluminum panels coated with those nano-composite formulations and tensile tests, thermogravimetric and SEM analyses were conducted on the free films prepared from the same coating formulations. An increase in abrasion resistance of CSBO-CPPG resin combination with the addition of silica was observed. In addition, the maximum weight loss of CSBO-CPPG resin combination was shifted to higher temperatures with incorporation of silica nano-particles The positive effect of modified silica particles on thermal stability of CSBO-CPPG system could be explained in such a way that PPG chains are able to disperse particles in the medium throughout the interactions between ether linkages and silanol groups

    Effect of nitrogen gas flushing treatments on total antioxidant capacity and ascorbic acid content in raw bovine milk during cold storage

    Get PDF
    Continuous nitrogen gas (N-2) flushing extends the shelf life of raw milk (RM) during cold storage. The effect of N-2 treatment on the total antioxidant capacity (TAC) and ascorbic acid (AA) content of RM was determined during cold storage. TAC of RM or deproteinized RM was determined by ABTS and DPPH methods, while L(+)-AA content of RM was determined chromatographically on days 0, 4 and 7 during storage at 6 +/- 1 degrees C. With the ABTS method, the TAC of RM decreased from 472.33 +/- 16.70 to 369.47 +/- 62.06 mu M TEAC while it reduced from 13.30 +/- 0.84 to 8.20 +/- 0.66 mu M TEAC with DPPH method during cold storage. TAC of RM determined with ABTS method decreased after 4 day-storage; however, they remained statistically similar for N-2-treated samples during 7 day-storage. The AA content of RM ranged from 14.06 to 10.76 mg/L during storage but N-2-treatment did not influence AA content significantly. Deproteinization reduced TAC values of milk samples significantly, and the reduction with the ABTS method was about 47.50 % for control samples cold-stored for four days, while it was 11.67 % for N-2-treated deproteinized RM. In conclusion, N-2-flushing through the headspace of milk containing vessels showed a significant protective effect on the antioxidant components of RM during cold storage.Peer reviewe

    Odabir autolitičkih bakterija mliječne kiseline kao mogućih starter kultura za ubrzavanje zrenja sireva u salamuri

    Get PDF
    The aim of this study was to select lactic acid bacteria (LAB) having autolytic activity on the basis of the technological aspects to accelerate the ripening of white-brined cheeses. For this purpose, mesophilic (n=526) and thermophilic (n=413) LAB isolates were collected from 34 raw milk and 16 cheese samples. 27 LAB isolates with a high autolytic activity ranging from 34 to 54 % were identified by (GTG)5 fingerprint and 16S rDNA sequence analyses, which showed that Lactococcus lactis and Enterococcus faecium were abundant among the autolytic isolates in raw milk while E. faecium and Lactobacillus casei were in white-brined cheese. The autolysis rate of LAB strains increased by raising the temperature and pH; however, decreased somewhat at high NaCl concentrations. Additionally, the highest autolysis was observed in the presence of glucose for most of the strains. On the other hand, Lb. plantarum PFC231 was autolyzed differently, being the highest in the presence of lactose. E. durans PFC235, E. faecium PFC232 and Lb. plantarum PFC231 were autolyzed more than other LAB strains, when exposed to low pH, high NaCI concentration at 10 °C simultaneously. However, only Lb. plantarum PFC231, Leuconostoc mesenteroides PFC234, Lc. lactis subsp. cremoris PFC233, Pediococcus acidilactici PFC237 and Lb. rhamnosus PFC238 were able to show intracellular caseinolytic activity. In conclusion, Lb. plantarum PFC231 has the potential to be used as an adjunct starter culture in the production of white-brined cheeses because of its autolysis at low temperature, pH and high salt concentrations, as well as intracellular caseinolytic activity.Cilj ovog rada bio je odabrati bakterije mliječne kiseline (LAB) koje imaju autolitičku aktivnost, kako bi se upotrebljavale za ubrzavanje procesa zrenja sireva u salamuri. U tu svrhu je iz 34 uzorka sirovog mlijeka te 16 uzoraka sira izolirano 526 mezofilnih i 413 termofilnih sojeva LAB. Primjenom 16SrDNA analize sekvenci i (GTG)5 metode otiska prsta izolirano je ukupno 27 sojeva s autolitičkom aktivnošću koja se kretala između 34 i 54 %. Pritom su se najdominantnijim autolitičkim vrstama u sirovom mlijeku pokazali Lactococcus lactis i Enterococcus faecium, dok su u siru prevladavali Enterococcus faecium i Lactobacillus casei. Stupanj autolize sojeva LAB rastao je s porastom temperature i pH, dok je opadao pri povišenim koncentracijama NaCl. Nadalje, kod svih sojeva je najveća autoliza zabilježena uz prisutnost glukoze. Međutim, soj Lb. plantarum PFC231 ovdje se izdvajao, pokazujući najveću autolizu u prisutnosti laktoze. Sojevi E. durans PFC235, E. faecium PFC232 i Lb. plantarum PFC231 su pri izloženosti niskom pH i visokoj koncentraciji NaCl pri 10 °C pokazivali viši stupanj autolize u odnosu na ostale sojeve. Međutim, samo su sojevi Lb. plantarum PFC231, Leuconostoc mesenteroides PFC234, Lc. lactis subsp. cremoris PFC233, Pediococcus acidilactici PFC237 i Lb. rhamnosus PFC238 pokazali sposobnost unutarstanične hidrolize kazeina. Zaključno, soj Lb. plantarum PFC231 jedini je pokazao potencijal za upotrebu kao starter kultura u proizvodnji sireva u salamuri, budući da ima autolitičku aktivnost pri niskim temperaturama i pH vrijednosti, te visokoj koncentraciji soli, a pokazao je i sposobnost unutarstanične hidrolize kazeina

    Wpływ hormonalnej terapii zastępczej oraz tamoxifenu na depresję u szczurów poddanych usunięciu jajników

    Get PDF
    Objectives: To determine the effects of tamoxifen and hormone replacement therapy in order to assess their role in depressive behavior. Material and Methods: Different protocols of hormone replacement therapies were administered to surgically ovariectomized rats. Intact rats were used for tamoxifen experiments. Properly assigned control groups were used and cognitive processes were studied on animal models of surgical menopause using the Porsolt Forced Swim Test and locomotor activity experiments. Results: In the tamoxifen experiments, an interaction between treatment and days did not reach statistical significance, but indicated a trend in this direction [F(1,26)=3.557, p=0.071]. The number of repeated movements significantly decreased after the Porsolt test (F(1,44) = 8.483, PCel: Określenie wpływu tamoxifenu oraz hormonalnej terapii zastępczej celem oceny ich roli w zachowaniach depresyjnych. Materiał i metody: Różne protokoły hormonalnej terapii zastępczej zastosowano u szczurów poddanych chirurgicznemu usunięciu jajników. Tamoxifen podawano szczurom, których nie operowano. Wykorzystano odpowiednio dobraną grupę kontrolną. Zbadano procesy poznawcze na modelach zwierzęcych z chirurgiczną menopauzą przy pomocy testu Porsolt Forced Swim oraz doświadczeń aktywności ruchowej. Wyniki: W doświadczeniach z tamoxifenem, związek pomiędzy terapią a dniami nie osiągnął statystycznej istotności, ale wykazał trend w tym kierunku [F(1,26)=3,557,p=0,071]. Liczba powtórzeń ruchów istotnie zmniejszyła się po teście Porsolta [F(1,44)=8,483,

    Utjecaj dodatka praha sluzi chia sjemenki (Salvia hispanica L.) na neka fizikalno-kemijska i reološka svojstva ayrana

    Get PDF
    In this study, chia seed mucilage powder (MP) was added into ayran drinks at different ratios (0.05, 0.10 and 0.15%, w/v), and its effect on physicochemical, rheological, microbiological and sensory properties of ayran drinks was determined during 10 days of storage at 4±1 °C. MP addition did not influence their major chemical composition significantly (p>0.05). Increasing MP ratio in drinks decreased the colour L* values of drinks while increasing their colour a* and b* values. Addition of 0.05, 0.10 and 0.15% MP reduced serum separation values of drinks by 25, 67 and 83%, respectively. The apparent viscosity value of control samples was 103.20 cP and increased to 134.25, 185.35 and 223.38 cP in ayran drinks with 0.05, 0.10 and 0.15% MP, respectively. The obtained results indicated that chia seed MP up to 0.05% can be used in ayran drink production to reduce serum separation and improve viscosity without any adverse effect on sensory liking scores.U ovom istraživanju, prah sluzi chia sjemenki (MP) dodan je u ayran napitke u različitim omjerima (0,05, 0,10 i 0,15 %, w/v) te je ispitivan njegov učinak na fizikalno-kemijska, reološka, mikrobiološka i senzorska svojstva ayran napitaka tijekom 10 dana skladištenja na 4±1 °C. Dodatak MP nije značajno utjecao na njihov glavni kemijski sastav (p>0,05). Povećanje omjera MP u pićima smanjilo je L* vrijednosti boje pića dok je povećalo njihove a* i b* vrijednosti boje. Dodatak 0,05, 0,10 i 0,15 % MP smanjio je vrijednosti sinereze napitaka za 25, 67 odnosno 83 %. Prividna viskoznost kontrolnih uzoraka bila je 103,20 cP i porasla je na 134,25, 185,35 i 223,38 cP u ayran napicima s 0,05, 0,10 i 0,15 % MP. Rezultati su pokazali da se MP chia sjemenki do 0,05 % može koristiti u proizvodnji ayrana, kako bi se smanjila sinereza i poboljšala viskoznost bez ikakvih negativnih učinaka na senzorska svojstva

    Hemoglobin is inversely related to flow-mediated dilatation in chronic kidney disease

    Get PDF
    The microcirculation is regulated by oxygen gradients and by endothelial release of nitric oxide, which can react with hemoglobin to form S-nitroso derivatives. Here we induced flow-mediated dilatation of the brachial artery in response to ischemia in 141 non-diabetic patients with stage 3–4 chronic kidney disease who had no history of smoking, cardiovascular events or use of erythropoietin-based agents. Patients with hemoglobin concentrations above the cohort median of 11.6 g/dl were found to have significant reductions in flow-mediated dilatation compared to those below the median. This inverse relationship remained significant after adjustment for potential confounders, including insulin sensitivity, glomerular filtration rate, proteinuria, body mass index, serum urate, etiology of underlying renal disease, treatment with anti-hypertensive drugs, and traditional Framingham risk factors. Given that hemoglobin can act as an important nitric oxide carrier and buffer, our studies suggest that the mechanism by which hemoglobin influences the endothelium-dependent microcirculation requires its nitrosylation; however, more direct studies need to be performed

    FGF-23 and vascular dysfunction in patients with stage 3 and 4 chronic kidney disease

    Get PDF
    Studies in animals show that fibroblast growth factor (FGF)-23 interferes with vascular reactivity induced by the nitric oxide (NO) system. To investigate the relationship between circulating FGF-23 levels and the response of forearm blood flow to ischemia (flow-mediated vasodilatation, FMD) and nitroglycerin, we tested 183 patients with stage 3-4 chronic kidney disease (CKD). None of them had cardiovascular complications or were taking drugs interfering with vascular function. Patients with FGF-23 levels above the median had significantly lower glomerular filtration rate, FMD, and fetuin-A levels (an anti-inflammatory molecule and potent inhibitor of calcification). They also had higher proteinuria and phosphate levels when compared to patients whose FGF-23 levels were below the median. The response to nitroglycerin was not different between the two groups. Multiple regression analysis showed that the relationship between FGF-23 and FMD was only modestly sensitive to adjustment for classical risk factors, biomarkers of bone mineral metabolism, high-sensitivity C-reactive protein, and homeostatic model assessment index. Adjustment for asymmetrical dimethyl arginine (ADMA) weakened the strength of this link; however, it remained highly significant. There was no independent association between FGF-23 and nitroglycerin. Thus, attenuation of FMD by ADMA suggests that this endogenous inhibitor of NO synthase may, in part, mediate the vascular effects of FGF-23 in patients with CKD. © 2010 International Society of Nephrology

    Observed variability in physical and biogeochemical parameters in the central Arabian Gulf

    Get PDF
    In situ measurements of physical and biogeochemical variables were conducted along a transect in the Exclusive Economic Zone (EEZ) of Qatar during late summer (September 2014) and winter (January 2015) to investigate their vertical, spatial and temporal variability. The study reveals that the water column is characterized by strong stratification during late summer in the deepest station, where the water depth is around 65 m and the surface to bottom temperature variation is around 9.1°C. The water column is vertically homogeneous during winter due to surface cooling and wind mixing. The surface to 23 m water column is characterized by ample dissolved oxygen (DO) during late summer and winter in the offshore regions, however, relatively low DO is found during late summer due to weak mixing and advection under weak winds and currents. Dissolved oxygen drops to hypoxic levels below the summer thermocline, and the winter high DO layer extends up to the bottom. Chlorophyll-a (Chl-a) is relatively high during late summer in the offshore region, while that in the nearshore regions is very low, which is linked to the anthropogenic stresses from the central east coast of Qatar. The results identified in this study fill an essential gap in the knowledge of regional primary production dynamics.Environmental Science Center (ESC) & Department of Biological and Environmental Sciences (DBES), Qatar University (QU

    Availability and affordability of blood pressure-lowering medicines and the effect on blood pressure control in high-income, middle-income, and low-income countries: an analysis of the PURE study data.

    Get PDF
    BACKGROUND: Hypertension is considered the most important risk factor for cardiovascular diseases, but its control is poor worldwide. We aimed to assess the availability and affordability of blood pressure-lowering medicines, and the association with use of these medicines and blood pressure control in countries at varying levels of economic development. METHODS: We analysed the availability, costs, and affordability of blood pressure-lowering medicines with data recorded from 626 communities in 20 countries participating in the Prospective Urban Rural Epidemiological (PURE) study. Medicines were considered available if they were present in the local pharmacy when surveyed, and affordable if their combined cost was less than 20% of the households' capacity to pay. We related information about availability and affordability to use of these medicines and blood pressure control with multilevel mixed-effects logistic regression models, and compared results for high-income, upper-middle-income, lower-middle-income, and low-income countries. Data for India are presented separately because it has a large generic pharmaceutical industry and a higher availability of medicines than other countries at the same economic level. FINDINGS: The availability of two or more classes of blood pressure-lowering drugs was lower in low-income and middle-income countries (except for India) than in high-income countries. The proportion of communities with four drug classes available was 94% in high-income countries (108 of 115 communities), 76% in India (68 of 90), 71% in upper-middle-income countries (90 of 126), 47% in lower-middle-income countries (107 of 227), and 13% in low-income countries (nine of 68). The proportion of households unable to afford two blood pressure-lowering medicines was 31% in low-income countries (1069 of 3479 households), 9% in middle-income countries (5602 of 65 471), and less than 1% in high-income countries (44 of 10 880). Participants with known hypertension in communities that had all four drug classes available were more likely to use at least one blood pressure-lowering medicine (adjusted odds ratio [OR] 2·23, 95% CI 1·59-3·12); p<0·0001), combination therapy (1·53, 1·13-2·07; p=0·054), and have their blood pressure controlled (2·06, 1·69-2·50; p<0·0001) than were those in communities where blood pressure-lowering medicines were not available. Participants with known hypertension from households able to afford four blood pressure-lowering drug classes were more likely to use at least one blood pressure-lowering medicine (adjusted OR 1·42, 95% CI 1·25-1·62; p<0·0001), combination therapy (1·26, 1·08-1·47; p=0·0038), and have their blood pressure controlled (1·13, 1·00-1·28; p=0·0562) than were those unable to afford the medicines. INTERPRETATION: A large proportion of communities in low-income and middle-income countries do not have access to more than one blood pressure-lowering medicine and, when available, they are often not affordable. These factors are associated with poor blood pressure control. Ensuring access to affordable blood pressure-lowering medicines is essential for control of hypertension in low-income and middle-income countries. FUNDING: Population Health Research Institute, the Canadian Institutes of Health Research, Heart and Stroke Foundation of Ontario, Canadian Institutes of Health Research Strategy for Patient Oriented Research through the Ontario SPOR Support Unit, the Ontario Ministry of Health and Long-Term Care, pharmaceutical companies (with major contributions from AstraZeneca [Canada], Sanofi Aventis [France and Canada], Boehringer Ingelheim [Germany amd Canada], Servier, and GlaxoSmithKline), Novartis and King Pharma, and national or local organisations in participating countries
    corecore