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Protective Properties (protective + property)
Selected AbstractsMultifunctional FeCo/TiN Multilayer Thin Films with Combined Magnetic and Protective Properties,ADVANCED ENGINEERING MATERIALS, Issue 12 2009Christian Klever Abstract Coatings with thicknesses ranging from a few nanometer up to several micrometer produced by physical vapor deposition (PVD) processes have been established in engineering technologies since the early 1980s. In particular, magnetron sputtered wear resistance coatings are industrially established and capable to enhance tool lifetimes significantly. However, in cases where optical inspection of a coating in use is not possible, an intrinsic sensor function of the film would be beneficial. Therefore, the development of wear resistant coatings with an integrated sensor functionality based on the insertion of a magnetoelastic ferromagnetic phase is suggested. In combination with appropriate read-out electronics such a film system would be ready for online monitoring of the coatings' actual state (e.g., strain, temperature, volume loss). This paper focuses on the development of wear resistance coatings which simultaneously supply beneficial mechanical properties as well as ferromagnetic properties optimized for online non-contact read-out applications. Multilayer coatings obtained through alternate stacking of magnetron sputtered TiN and FeCo layers with a nominal total thickness of 1000,nm were produced as a model system meeting the above conditions. The bilayer period was varied down to 2.6,nm while the individual layer thickness ratio tTiN/tFeCo was determined by the deposition rates and maintained constant at a value of about 3/1. The films were vacuum annealed ex situ in a static magnetic field subsequent to the deposition. The constitution of the as-deposited and annealed coatings as well as their mechanical (nanohardness, Young's modulus) and magnetic properties (magnetization hysteresis, frequency-dependent permeability) are described. Finally, the suitability of the coatings for the use in remote-interrogable wear sensor applications is briefly discussed. [source] Contribution of endothelium-derived hyperpolarizing factors to the regulation of vascular tone in humansFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 4 2008Jeremy Bellien Abstract Endothelium plays a crucial role in the regulation of cardiovascular homeostasis through the release of vasoactive factors. Besides nitric oxide (NO) and prostacyclin, increasing evidences show that endothelium-derived hyperpolarizing factors (EDHF) participate in the control of vasomotor tone through the activation of calcium-activated potassium channels. In humans, the role of EDHF has been demonstrated in various vascular beds including coronary, peripheral, skin and venous vessels. The mechanisms of EDHF-type relaxations identified in humans involved the release by the endothelium of hydrogen peroxide, epoxyeicosatrienoic acids (EETs), potassium ions and electronical communication through the gap junctions. The role of EETs could be particularly important because, in addition contributing to the maintenance of the basal tone and endothelium-dependent dilation of conduit arteries, these factors share many vascular protective properties of NO. The alteration of which might be involved in the physiopathology of cardiovascular diseases. The evolution of EDHF availability in human pathology is currently under investigation with some results demonstrating an increase in EDHF release to compensate the loss of NO synthesis and to maintain the endothelial vasomotor function whereas others reported a parallel decrease in NO and EDHF-mediated relaxations. Thus, the modulation of EDHF activity emerges as a new pharmacological target and some existing therapies in particular those affecting the renin,angiotensin system have already been shown to improve endothelial function through hyperpolarizing mechanisms. In this context, the development of new specific pharmacological agents especially those increasing EETs availability may help to prevent endothelial dysfunction and therefore enhance cardiovascular protection in patients. [source] Interactions between N,acetylcysteine and sodium selenite in modulating the clastogenicity of urethane and 2,acetylaminofluorene in miceINTERNATIONAL JOURNAL OF CANCER, Issue 1 2004Roumen M. Balansky Abstract Combined treatment with different agents represents a promising approach in cancer chemoprevention. Therefore, it is useful to assess in preclinical models the efficacy of combinations that are selected by taking into account mechanistic considerations. We designed 2 studies evaluating the interaction between N,acetylcysteine (NAC) and sodium selenite (Se), both given with the drinking water to Balb/c mice, in modulating clastogenic effects in bone marrow polychromatic erythrocytes. In a first study, a single i.p. injection of urethane considerably enhanced the frequency of micronucleated cells. While NAC produced a significant inhibition, Se further enhanced urethane clastogenicity. When given in combination at the same doses, NAC prevented the adverse effect of Se. In a second study, a single i.p. injection of 2,acetylaminofluorene enhanced the frequency of micronucleated cells. Se did not reduce this effect to a significant extent, while NAC produced a dose,dependent inhibition. When tested at the lower dose in combination with Se, the protective effect of NAC was unchanged. Especially in association with Se, NAC also prevented the toxicity of 2,acetylaminofluorene by normalizing the ratio of polychromatic to normochromatic erythrocytes. In conclusion, NAC attenuated the clastogenicity of both urethane and 2,acetylaminofluorene and the toxicity of this aromatic amine. In addition, NAC prevented the clastogenic and toxic effects resulting from the interaction of Se with urethane. Together with the findings of previous studies, it appears that, besides its intrinsic protective properties in carcinogenesis, NAC is capable of attenuating the adverse effects of several cytotoxic drugs and chemopreventive agents. © 2003 Wiley-Liss, Inc. [source] Smoking May Impair the Bone Protective Effects of Nutritional Calcium: A Population-Based Approach,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2003Joonas Sirola PhD Abstract Postmenopausal women were randomly selected to investigate the effects of smoking on prevention of bone loss with nutritional calcium. DXA was performed twice, and smoking and calcium intake habits were inquired through the mail in 954 women. Smoking dampened the bone protective effects of nutritional calcium. This may reflect the pathophysiology underlying smoking-induced bone loss postmenopause. This study evaluated the effect of smoking on the bone protective properties of nutritional calcium. Of the random sample of 954 peri- and postmenopausal women selected from the Osteoporosis Risk Factor and Prevention (OSTPRE) study cohort (n = 13,100) in Kuopio, Finland, 182 had smoked at some time (ever smokers) and 772 had never smoked. Women were divided in tertiles according to self-reported dairy nutritional calcium intake (mg/day): <648 (1st), 648-927 (2nd), >927 (3rd). Bone mineral density at lumbar spine (LS) and femoral neck (FN) was measured with DXA at baseline in 1989-1991 and at the 5-year follow-up in 1994-1997. In a linear regression model, nutritional calcium intake did not predict annual bone loss in smokers. These results were similar in the subanalysis on 71 current smokers (at both baseline and 5-year measurements) and on 85 past smokers. In never smokers, a statistically significant linear trend was observed between calcium intake and annual bone loss at LS, but at FN only after adjustment for age, weight, hormone replacement therapy (HRT), and other covariates. In analysis of covariance (ANCOVA), no differences in bone loss rate were observed between calcium intake tertiles among smokers. In nonsmokers, the annual bone loss rate was lower in the second (,0.41%) and the third (,0.35%) tertile compared with the first tertile (,0.61%) at LS (p < 0.05) and lower in the third tertile (,0.55%) than in first tertile (,0.72%) at FN after adjustment for age, weight, HRT, and other covariates (p < 0.05). When smokers were added to the nonsmoker group, the differences in bone loss rate between calcium intake tertiles disappeared. In addition, in ANCOVA, the term of interaction between smoking and calcium intake was statistically significant at LS only. In conclusion, smoking seems to impair the bone protective effects of nutritional calcium in postmenopausal women, more clearly in LS than FN. [source] Excitotoxic damage, disrupted energy metabolism, and oxidative stress in the rat brain: antioxidant and neuroprotective effects of l -carnitineJOURNAL OF NEUROCHEMISTRY, Issue 3 2008Daniela Silva-Adaya Abstract Excitotoxicity and disrupted energy metabolism are major events leading to nerve cell death in neurodegenerative disorders. These cooperative pathways share one common aspect: triggering of oxidative stress by free radical formation. In this work, we evaluated the effects of the antioxidant and energy precursor, levocarnitine (l -CAR), on the oxidative damage and the behavioral, morphological, and neurochemical alterations produced in nerve tissue by the excitotoxin and free radical precursor, quinolinic acid (2,3-pyrindin dicarboxylic acid; QUIN), and the mitochondrial toxin, 3-nitropropionic acid (3-NP). Oxidative damage was assessed by the estimation of reactive oxygen species formation, lipid peroxidation, and mitochondrial dysfunction in synaptosomal fractions. Behavioral, morphological, and neurochemical alterations were evaluated as markers of neurotoxicity in animals systemically administered with l -CAR, chronically injected with 3-NP and/or intrastriatally infused with QUIN. At micromolar concentrations, l -CAR reduced the three markers of oxidative stress stimulated by both toxins alone or in combination. l -CAR also prevented the rotation behavior evoked by QUIN and the hypokinetic pattern induced by 3-NP in rats. Morphological alterations produced by both toxins (increased striatal glial fibrillary acidic protein-immunoreactivity for QUIN and enhanced neuronal damage in different brain regions for 3-NP) were reduced by l -CAR. In addition, l -CAR prevented the synergistic action of 3-NP and QUIN to increase motor asymmetry and depleted striatal GABA levels. Our results suggest that the protective properties of l -CAR in the neurotoxic models tested are mostly mediated by its characteristics as an antioxidant agent. [source] Expression Of O-Acetyl Sialic Acid On Cerebral Microcirculation In A Glycine Or Taurine Treated Diabetic Rat ModelJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2000A Noe Expression of sialic acid is altered in Diabetes mellitus. This modification has also been involved with both vascular and neurologic diseases, and with the increase of no enzymatic glycosylation of proteins. In our opinion, the lectins were very useful with specificity for sialic acids in order to determine the level of sialic acid expression on cerebral microcirculation in a diabetic Wistar rat model with streptozotocin. In this model, the glycine (1%) and taurine (0.5%) aminoacids were placed in drinking-water by six months. At the end of this time, the animals were sacrificed, their brains surgically removed and frozen in liquid nitrogen, and the specimens cut in serial sections. Immediately, the sections were incubated with different biotin-labelled lectins specific to sialic acid using peroxidase-labelled avidin as second ligand and H2O2 chromogen. The results showed greater O-acetyl sialic acid expression in cerebral capillaries of untreated diabetic rats than in glycine-, taurine-treated diabetic rats or than in control animals. The minor sialic acid expression may be an indicator of degenerative diseases such as Alzheimer's or the vascular disease of diabetic patients and probably is related to cellular protective properties of the glycine and taurine aminoacids. These first protective characteristics that have been observed in both ischemia with cellular ATP depletion models, suggest the utilization of aminoacids glycine or taurine in diabetic patient in order to avoid the development of microinfarcts. [source] Effects of yeast probiotic formulation on viability, revival and protection against infection with Salmonella enterica ssp. enterica serovar Typhimurium in miceLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2009F.S. Martins Abstract Aims:, To compare the effects of five yeast probiotic formulations on viability, revival and washout kinetic in the digestive tract of mice, and the protection against an experimental infection with Salmonella enterica serovar Typhimurium. Methods and Results:, The number of viable cells in five commercial probiotic products codified as A, B, C and D (Saccharomyces boulardii, lyophilized) and E (Saccharomyces cerevisiae, aqueous suspension) was determined, as well as revival and washout kinetic in mouse intestine. Protective capacity was evaluated by survival rate and histopathology of liver and intestine of mice treated with each product and then challenged with Salm. Typhimurium. Conclusions:, Product A contained the highest number of viable cells and, fed to mice, gave the highest counts of viable yeasts and the longest persistence in faeces. Probably as a consequence, the highest survival and protection of intestinal and hepatic tissues were observed when product A was used for mouse treatment. Product E showed low counts in the formulation and was not recovered from mouse intestine. Significance and Impact of the Study:, Formulation (lyophilization or aqueous suspension) is an important factor for revival and survival of a probiotic product in vivo and consequently for its protective properties. [source] The wet corrosion of molybdenum thin film , Part III: The effect of Ti and NbMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 5 2006C. R. Tomachuk Abstract Magnetron sputtering has become the process of choice for the deposition of a wide range of industrially important coatings. Over the last decade, interest in molybdenum thin films prepared by magnetron sputtering has been increasing; however, little research has been done on molybdenum-titanium and molybdenum-niobium alloy thin films. During the current study, electrochemical impedance spectroscopy (EIS) was employed to investigate the effect on the corrosion resistance in basic chloride environments of adding titanium and niobium species to molybdenum thin films deposited by physical vapor deposition. The results indicate that the MoTi alloy thin films exhibit better protective properties than either the molybdenum-niobium alloy or unalloyed molybdenum thin films. [source] Inhibition of corrosion of AZ91 magnesium alloy in ethylene glycol solution in presence of chloride anionsMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 2 2005E. Slavcheva Abstract The influence of chloride ions on the corrosion of AZ91 magnesium alloy in water/ethylene glycol solutions and the inhibiting effect of lactobiono-tallowamide (LTA) were investigated using electrochemical and surface analysis methods. Potentiodynamic polarization curves in aqueous solution of ethylene glycol (50:50w%) containing 0.1 g.L,1 chloride and up to 0.5 g.L,1 LBT were obtained at room and at elevated temperatures. The chloride anions showed a distinct deteriorating effect as they caused pit initiation and accelerated the dissolution of the tested alloy. The selected organic compound demonstrated good protective properties against corrosion of AZ91 magnesium alloy and behaved as inhibitor of mixed type hindering both the cathodic and the anodic partial reactions. It showed inhibition efficiency of 77% at relatively low concentration of 0.2 g.L,1 and was considered as a promising corrosion inhibitor. The mechanism of inhibition was discussed on the basis of the electrochemical impedance spectroscopy (EIS) and XRD analysis of the surface. [source] Relative protective properties of three membrane glycoprotein fractions from Haemonchus contortusPARASITE IMMUNOLOGY, Issue 2 2000Smith Jacalin lectin was used as a ligand to isolate a fraction containing two distinct protective antigens from detergent extracts of membranes from Haemonchus contortus. The first antigen was identified as a complex which appeared very similar to Haemonchus galactose-containing glycoprotein (H-gal-GP), which is a previously described protective protease complex, except that it was substantially depleted of one of the main H-gal-GP components, a 230 kDa metallopeptidase-containing band. The new complex was termed Haemonchus sialylated galactose-containing glycoprotein (H-sialgal-GP), because it bound to jacalin but not to peanut lectin and only jacalin will bind the sialylated form of galactosyl (,-1,3) N -acetylgalactosamine. Two protection trials with sheep showed that H-sialgal-GP and H-gal-GP were equally efficacious, reducing numbers of Haemonchus eggs by between 86% and 93% and worms by between 52% and 75%, respectively. The second jacalin-binding protective antigen fraction was separated from H-sialgal-GP by ion exchange and gel filtration chromatography. It was greatly enriched for two proteins termed p46 and p52 according to their apparent molecular weights. Immunization of sheep with these proteins gave protection values of 78% for eggs and 33% for worms, which are significantly lower than those obtained with either H-gal-GP or H-sialgal-GP. N -terminal amino acid sequence data from p46 and p52 showed that both proteins were closely related to a previously described 45 kDa Haemonchus membrane protein, which had conferred protection against Haemonchus in guinea-pigs. [source] Deposition of SiO, -Like Thin Films from a Mixture of HMDSO and Oxygen by Low Pressure and DBD Discharges to Improve the Corrosion Behaviour of SteelPLASMA PROCESSES AND POLYMERS, Issue S1 2007Camille Petit-Etienne Abstract Hexamethyldisiloxane was used to deposit silicon dioxide thin films using a low frequency plasma reactor at low pressure as well as a dielectric barrier discharge (DBD) at atmospheric pressure. FT-IR, XPS, EIS, SEM and ellipsometry were used to analyse the samples. The results show that, at low pressure, the deposited films which are smooth, continuous and dense present a polymer-like structure. By carrying out the film deposition after an oxygen plasma pretreatment step, a further improvement in the protective properties is achieved, which is observed in the case of SiO, coatings with 13.56 MHz RF generators.1 At atmospheric pressure, the deposited films present an inorganic character deposited in open air and a polymer-like one deposited under a controlled nitrogen atmosphere in our DBD reactor. The latter also allows continuous films which present the best anti-corrosive properties (which have been studied for the first time for anti-corrosive properties) when they contain some carbon incorporated. [source] Haplotypes Encompassing the KIAA0391 and PSMA6 Gene Cluster Confer a Genetic Link for Myocardial Infarction and Coronary Artery DiseaseANNALS OF HUMAN GENETICS, Issue 5 2009Osama Alsmadi Summary The role of the KIAA0391 and PSMA6 genes in predisposing individuals to disease is still not fully understood. We evaluated by molecular beacon-based genotyping assays the roles of five single nucleotide polymorphisms (SNPs) in the chromosomal region 14q13.2 harbouring the KIAA0391 and PSMA6 gene cluster in coronary artery disease (CAD) in the Saudi population. Two of the studied SNPs rs8008319 (denoted as 1) and rs7157492 (2), reside in the KIAA0391 locus, two others rs1048990 (3) and rs12878391 (4) are components of the PSMA6, while rs4981283 (5) resides downstream of both genes. In a study involving 1071 patients and 929 controls, none of the studied SNPs showed significant association with CAD. In contrast, two haplotypes consisting of 1A-2G-3C-4A-5A [O.R.(95% C.I.) = 1.49(0.95,2.35); p = 0.022] and 1A-2G-3G-4A-5A [2.24(0.84,5.98); p = 0.031] conferred risk for both CAD and myocardial infarction (MI) in a five-SNP locus model, while another comprising 1A-2G-3C-4A-5G [2.24(0.84,5.98); p = 0.079] showed a borderline association. One haplotype consisting of 1T-2G-3C-4G-5A [0.79(0.59,1.05); p = 0.015] exhibited protective properties and another, 1T-2G-3C-4A-5G [0.20(0.03,139); p = 0.073], showed a similar but weaker trend. Our study identified haplotypes in the chromosomal region encompassing the KIAA0391 and PSMA6 genes as a possible genetic link between CAD and MI. These results also suggest that haplotypes may be more informative than individual SNPs in identifying risk factors for disease. [source] Evaluation of the effect of autologous mesenchymal stem cell injection in a large-animal model of bilateral kidney ischaemia reperfusion injuryCELL PROLIFERATION, Issue 3 2009L. Behr Objectives: Adult mesenchymal stem cells (MSC) have been proven to be of benefit to the kidney in different experimental models of renal injuries. All studies have been performed in valuable rodent models, but the relevance of these results to large mammals and ultimately, to humans remains unknown. Therefore, the aim of this study was to investigate the effect of MSC transplantation in an alternative ovine large-animal model of bilateral kidney ischaemia reperfusion injury. Material and methods: Sheep were divided into three groups: one sham-operated group and two groups submitted to renal bilateral ischaemia for 60 min. Animals with ischaemia reperfusion injury were treated with injection of autologous MSCs or with vehicle medium. Results: The model sheep presented with renal histological manefestations that closely resembled lesions seen in patients. Transplanted MSCs were found in glomeruli but not in tubules and did not express glomerular cell markers (podocin, von Willebrand factor), but functional evaluation showed no beneficial effect of MSC infusion. Morphological and molecular analyses corroborated the functional results. MSCs did not repair kidney parenchyma and failed to modulate cell death and proliferation or cytokine release (tumour necrosis factor-alpha, vascular endothelial growth factor alpha (VEGF-,), Bcl-2, caspase). Conclusion: In this unique autologous large-animal model, MSCs did not exhibit reparative or paracrine protective properties. [source] | ||||||||||||||||