Effects of nerve and fibroblast growth factors on the production of nitric oxide in experimental model of Huntington's disease

The role of nitric oxide (NO) in neurological diseases represents one of the most studied, yet controversial subjects in physiology. The aim was to examine the effects of intrastriatal injection neurotrophins (nerve growth factors-NGF, fibroblast growth factors-FGF) in order to investigate the possible involvement of NO in quinolinic acid (QA) induced striatum toxicity in the rat model of Huntington's disease (HD). QA was administered unilaterally into the striatum of adult Wistar rats in a single dose of 150 nM. The other two groups of animals were pretreated immediately before QA application with NGF and FGF, respectively. Control group was treated with 0.9% saline solution in the same manner. Animals were decapitated 7 days after the treatment. Nitrite levels were significantly decreased both in the ipsi- and contra lateral striatum and forebrain cortex of NGF- and FGF-treated animals compared with QA treatment. These results indicated a temporal and spatial propagation of oxidative stress and spread protective effects of NGF and FGF on the forebrain cortex, the distant structure, but tightly connected with striatum, the place of direct neurotoxin damage. Neurotrophins could be the potential neuroprotective agents in HD

Pentoxifylline Prevents Autoimmune Mediated Inflammation in Low Dose Streptozotocin Induced Diabetes

Xanthine derivative, pentoxifylline (PTX), has been recently shown to exert a protective effects in certain animal models of autoimmunity, including diabetes in NOD mice. In the present study, the immunomodulatory potential of PTX was investigated in autoimmune diabetes induced by multiple low doses of streptozotocin (MLD-SZ) in genetically susceptible CBA/H mice (tested with 40 mg SZ/kg b.w. for 5 days) and DA rats (tested with 20 mg/kg b.w. for 5 days). In both species, 2 – 3 weeks following the MLD-SZ treatment, sustained hyperglycemia developed, as an outcome of inflammatory reaction with endothelial cell activation and accumulation of mononuclear cells. Although there was no evidence of typical insulitis in early disease development (day 10), in both rats and mice, macrophages, CD4+ and CD8+ cells were present in the islets of Langerhans as diffuse mononuclear infiltrates with the expression of IFN-γ and inducible NO synthase (iNOS). Administration of PTX (200 mg/kg/day for 10 days) in combination with MLD-SZ reduced insulitis and the production of mediators tested, and prevented the development of hyperglycemia. These results suggest that beneficial effects of PTX involve down-regulation of local proinflammatory cytokine-mediated NO synthase pathway. They also demonstrate that in addition to ameliorating spontaneous autoimmunity in NOD mice, PTX may be effective in downregulating an inflammatory autoimmune process triggered in susceptible host by an external agents, such as streptozotocin

Novi način formiranja kompozitnih prevlaka

Ni/WC and Cu/WC composite coatings were obtained in two steps. The first step consists of the inert WC particles deposition from the aqueous solution onto steel surface by means of a micro-pipette and covering by the dilute aqueous Nafion solution. The second step is the electrochemical metal deposition from commercial baths in constant current regimes. As result, compact composite coatings were obtained with the different amounts of WC in the deposit in the entire range between a part of a percent up to a few tenths of the percent. The new two-steps method for the formation of the composite coatings renders a very homogeneous distribution of inert WC particles in the deposit and exactly defined chemical composition in each part of the coating Several advantages of splitting the process into two steps are found: the electrolyte for the metal deposition stays clean, no stirring is necessary and it is possible to deposit homogeneously large particles at desired parts of the surface. It is also possible to form multi-layer composite deposits as well as composite foils.Kompozitne prevlake nikal-volframkarbid Ni/WC i bakar-volframkarbid Cu/WC dobijene su iz dva stupnja. Prvi stupanj obuhvata nanošenje inertnih čestica volframkarbida (WC) iz vodenog rastvora mikropipetom na čeličnu površinu. Preko nanetih čestica sipan je razblažen vodeni rastvor nafiona. Drugi stupanj predstavlja elektrohemijsko taloženje metala iz komercijalnih elektrolita pri konstantnom strujnom režimu. Kao rezultat dobijene su kompaktne kompozitne prevlake, gde je količinu WC moguće menjati od dela procenta do nekoliko desetina procenata. Korišćenjem dvostepenog formiranja kompozitnih prevlaka dobija se homogena raspodela inertnih čestica u prevlaci i tačno definisan hemijski sastav u svakom delu prevlake. Prednost ovakvog formiranja kompozitnih materijala je velika, jer ne dolazi do prljanja elektrolita za taloženje osnovnog metala, nije potrebno nikakvo mešanje elektrolita, a moguće je ugraditi velike i teške čestice i to na tačno definisanim mestima na površini. Takođe, moguće je formirati i višeslojne kompozitne prevlake, kao i kompozitne folije

Karakteristike legura Ni-W elektrohemijski taloženih konstantnom i pulsirajućom strujom

The Ni-W alloys were electrochemically deposited from a ammonia-citrate electrolyte on rotation disc electrode with a replaceable steel disc, by direct and pulsed current. The aim of the paper is investigations of parameters of deposition, structure of alloys and temperature treatment on morphology and micro hardness of alloys.Prevlake legure Ni-W su elektrohemijski taložene iz amonijačno-citratnog elektrolita, na rotirajuću disk elektrodu od čelika, konstantnom i pulsirajućom strujom. Cilj rada je ispitivanje uticaja parametara taloženja sastava legure i termičkog tretmana na morfologiju i mikrotvrdoću dobijenih prevlaka

Elektrohemijsko dobijanje i karakterizacija prevlaka legura cink-gvožđe

The influence of the deposition current density and temperature of deposition solution on the phase structure and corrosion properties of Zn-Fe alloys was examined. Alloys were deposited on a rotating disc electrode and on steel panels from alkaline plating bath. The chemical content was determined by EDX analysis, phase structure by anodic linear sweep voltammetry (ALSV) and corrosion properties by polarization measurements and by determining the time of the red rust appearance for Zn-Fe alloys. It was shown that Zn-Fe alloy with the best corrosion properties, among all investigated n this work, was obtained at room temperature at 4 A dm"2.Izučavan je uticaj gustine struje taloženja i temperature rastvora za taloženje na hemijski i fazni sastav, kao i na korozionu stabilnost legura Zn-Fe. Legure su taložene na rotirajućoj disk elektrodi i čeličnim pločicama iz alkalnog rastvora. Hemijski sastav je određivan analizom disperzije X-zraka (EDX), fazni sastav metodom anodne linearne promene potencijala (ALPP), a koroziona stabilnost polarizacionim merenjima, kao i praćenjem promene potencijala otvorenog kola sa vremenom delovanja korozionog agensa. Pokazano je da najveću korozionu stabilnost ima legura dobijena taloženjem na sobnoj temperaturi sa 4 A dm2

Elektrohemijsko taloženje i koroziona stabilnost prevlaka Zn-Co legura

The influence of the type of the deposition solution, deposition current density and temperature of deposition solution on the phase structure and corrosion properties of Zn-Co alloys was examined. Alloys were deposited on a rotating disc electrode from chloride and sulphate plating bath. The phase structure was determined by anodic linear sweep voltammetry (ALSV) and corrosion properties by polarization measurements. It was shown that Zn-Co alloys with the best corrosion properties, among all investigated in this work, were obtained from chloride plating bath at room temperature at 4,5 and 5 A dm-2.Izučavan je uticaj vrste rastvora za taloženje, gustine struje taloženja i temperature rastvora za taloženje na fazni sastav, kao i na korozionu stabilnost legura Zn-Co. Legure su taložene na rotirajućoj disk elektrodi iz sulfatnog i hloridnog rastvora. Fazni sastav legura je određivan metodom anodne linearne promene potencijala (ALPP), a koroziona stabilnost polarizacionim merenjima. Pokazano je da najveću korozionu stabilnost imaju legure dobijene taloženjem iz hloridnog rastvora na sobnoj temperaturi sa 4,5 i 5 A dm-2

The corrosion behaviour of epoxy-resin electrocoated steel

a.c. Impedance measurements carried out on epoxy-resin electrocoated steels have been used to determine the pore resistance of the organic films as a function of time of exposure to 3% NaCl solution. The time dependence of pore resistance for the electrodeposited coatings, formed at different voltages, shows the effect of applied voltage on the protective properties of organic layers. The results were interpreted in terms of a model in which the solution rapidly penetrates capillaries or defects in the coating followed by diffusion of solution through the coating. The model predicted the relationship between film thickness and useful life of the film, i.e. the model showed that useful life of coating depends on the square of film thickness

Kompozitne Ni/WC prevlake dobijene elektrohemijskim taloženjem konstantnom i pulsirajućom strujom

The properties of composite coatings are dependent on properties of the base metal, as well as on properties of incorporating particles. The Ni / W composite coatings were obtained by electro deposition from commercially available Vat bath containing additives for brightness and smoothing of the surface and insoluble WC particles. Before the deposition, magnetic mixer was used and rotating disc electrode (RDE) was used for deposition of the composite. It was showed that the amount of WC in the coating could be altered from parts of percent to over 80 percents., as a result of appropriate regime of mixing and deposition. It was also showed that the amount of insoluble WC in Vat bath had no significant influence on the amount of WC in the coating.Osobine kompozitnih prevlaka zavise od osobina osnovnog metala koji čini kompozit, kao i osobina čestica koje se ugrađuju. Kompozitne prevlake nikal-volframkarbid dobijene su elektrohemijskim taloženjem iz komercijalnog, Vatovog elektrolita za taloženje osnovnog metala nikla, koji sadrži dodatke za sjaj i poravnavanje površine i nerastvornih čestica volframkarbida. Za mešanje elektrolita korišćena je magnetna mešalica (pre taloženja), a za taloženje kompozita korišćena je rotirajuća disk elektroda RDE. Kao rezultat dobijeno je da pri odgovarajućem režimu taloženja i mešanja elektrolita količinu volframkarbid u prevlaci je moguće menjati od dela procenta do preko osamdeset procenata. Takođe, dobijeno je da korišćenjem RDE i magnetne mešalice sadržaj volframkarbida u Vatovom elektrolitu пeтa veliki uticaj na sadržaj volframkarbida и prevlaci

Kompozitne Ni/WC prevlake dobijene elektrohemijskim taloženjem konstantnom i pulsirajućom strujom

The properties of composite coatings are dependent on properties of the base metal, as well as on properties of incorporating particles. The Ni / W composite coatings were obtained by electro deposition from commercially available Vat bath containing additives for brightness and smoothing of the surface and insoluble WC particles. Before the deposition, magnetic mixer was used and rotating disc electrode (RDE) was used for deposition of the composite. It was showed that the amount of WC in the coating could be altered from parts of percent to over 80 percents., as a result of appropriate regime of mixing and deposition. It was also showed that the amount of insoluble WC in Vat bath had no significant influence on the amount of WC in the coating.Osobine kompozitnih prevlaka zavise od osobina osnovnog metala koji čini kompozit, kao i osobina čestica koje se ugrađuju. Kompozitne prevlake nikal-volframkarbid dobijene su elektrohemijskim taloženjem iz komercijalnog, Vatovog elektrolita za taloženje osnovnog metala nikla, koji sadrži dodatke za sjaj i poravnavanje površine i nerastvornih čestica volframkarbida. Za mešanje elektrolita korišćena je magnetna mešalica (pre taloženja), a za taloženje kompozita korišćena je rotirajuća disk elektroda RDE. Kao rezultat dobijeno je da pri odgovarajućem režimu taloženja i mešanja elektrolita količinu volframkarbid u prevlaci je moguće menjati od dela procenta do preko osamdeset procenata. Takođe, dobijeno je da korišćenjem RDE i magnetne mešalice sadržaj volframkarbida u Vatovom elektrolitu пeтa veliki uticaj na sadržaj volframkarbida и prevlaci

Elektrohemijsko taloženje i karakterizacija legura cink-nikal dobijenih konstantnom i reversnom strujom

Zn-Ni alloys electrochemically deposited on steel under various deposition conditions were investigated. The alloys were deposited on a rotating disc electrode and on a steel panel from chloride solutions by direct and reverse current. The influence of reverse plating variables (cathodic and anodic current densities and their time duration) on the composition, phase structure and corrosion properties were investigated. The chemical content and phase composition affect the anticorrosive properties of Zn-Ni alloys during exposure to a corrosive agent (3%NaCl solution). It was shown that the Zn-Ni alloy electrodeposited by reverse current with a full period T = 1 s and r=0.2 exhibits the best corrosion properties of all the investigated alloys deposited by reverse current.Ispitivani su hemijski sastav i fazna struktura legura Zn-Ni dobijenih primenom različitih parametara elektrohemijskog taloženja. Legure su taložene na rotirajućoj disk elektrodi i na čeličnim pločicama konstantnom i reversnom strujom. Ispitivani su parametri reversne struje (katodne i anodne gustine struje taloženja, i njihovog vremena trajanja) na sastav, faznu strukturu i korozione osobine legura. Pokazano je da hemijski sastav i fazna struktura utiču na korozione osobine Zn-Ni legura tokom izlaganja dejstvu rastvora 3%NaCl. Legura Zn-Ni dobijena reversnom strujom sa T=1 s i r=0.2 ima najbolje korozione osobine