236 research outputs found
Electrical and Optical Properties of Flexible Transparent Silver Nanowires electrodes
AgNWs were produced by the one-pot polyol method, and it had been produced by reduction of AgNO3 by ethylene glycol in presence of polyvinylpyrrolidone (PVP) and KCl at high temperature of about 160 oC. AgNWs suspension were purified by centrifuging at 3000 rpm for three times then re-depressed in deionized water with a concentration of 1%. The purified suspension was diluted to different concentrations (2-5) mg. mL-1 using 1% of hydroxy methylcellulose to design different AgNWs transparent conductive films (AgNWs-TCFs). AgNWs suspension inks were coated on the glass and polyethylene terephthalate (PET) substrates. Different AgNWs diameters were obtained by changing the synthesis conditions. It has been observed that the wire diameter will greatly affect both the optical and electrical properties of the obtained AgNWs-TCFs. The best obtained AgNWs-TCFs had high transparency of about 91.5 %, small sheet resistance of about 14 .03 Ω and optical haze less than 2%, which met the requirements for the manufacture of optoelectronic and sensor equipment. Keywords: Silver nanowires, transparent conductive electrode, flexible electrodes, polyol method, AgNWs size control, AgNWs size-dependent and one-pot synthesis
The role of losartan and enalapril in the protection against stress-induced gastric mucosal ulceration in rats
Background: Angiotensin II (ANG II) is a stress hormone and its level dramatically increases in the stomach during stress. In addition, it generates reactive oxygen species (ROS) with cellular damage and inflammation. So the aim of this study is to evaluate the mechanism of losartan and enalapril in the prevention of stress-induced gastric ulcer through their action on mucosal prostaglandin (PGs) and antioxidant enzymes and compare between them.Methods: Thirty- six adult male wistar albino rats weighing 180-200 g were divided into 6 groups; n= 6. Groups 1, 2, and 3 were received saline (normal control), losartan (3 mg/kg/day) and enalapril (10 mg/kg/day) i.p respectively for 4 weeks. Groups 4, 5, and 6 were pretreated with saline (ulcer control), losartan (3 mg/kg/day) and enalapril (10 mg/kg/day) i.p respectively for 4 weeks duration. On 29th day, group 4, 5 and 6 were submitted to gastric ulcer by water immersion method, then animals of all groups were sacrificed, stomachs were excised for gross and microscopic examination and determination of the mucosal levels of prostaglandin E2 (PGE2), superoxide dismutase (SOD), nitric oxide (NO) and catalase (CAT).Results: Stress produced gastric ulcer and a significant decrease in all measured gastric parameters compared to normal control group. Pre-treatment of rats with losartan or enalapril decreased the stress-induced alterations in mucosal parameters, but only losartan caused a significant increase in CAT activity in addition.Conclusions: Antagonize the action of ANG II by losartan and enalapril have preventive advantages in stress-induced gastric ulcer and losartan has better influence as it has an additional effect on CAT activity
Evaluation of serological test in the diagnosis of Helicobacter pylori and risk factors associated with the infection
Background: Serological testing has been widely used for the diagnosis of H. pylori. This study aimed to evaluate the serological test and to determine the sensitivity and specificity of the test in the diagnosis of H. pylori. The study also aimed to address if there are risk factors like blood grouping, Smoking, Age, gender, and residence of the patients associated with H. pylori infection.Methods: A prospective cross‑sectional study was performed among 100 symptomatic patients attending Dr. Suliman dispensary, Elnehoud city in west Kordofan state-Sudan, from March to September 2016. H. pylori were detected on plasma by using Healgen immunochromatography test cards from Xiamen Boson Biotech Co., Ltd (China), and identified from a stool by using monoclonal antigen detection from the same trademarked company. Data for the risk factors associated with the infection were assessed in a participant interview.Results: The serological test showed significant differences when compared to the stool antigen test p-value = 0.000. The statistical analysis showed moderate sensitivity and high specificity of the serological test compared to the stool antigen detection test. The study also showed that smoking [odds ratio (OR): 1.20, 95% confidence interval (CI): (1.24-4.02) and blood grouping (OR: 1.10, 95% CI: (1.08-1.60) were risk factors for H. pylori infection.Conclusions: The serological test showed high specificity and moderate sensitivity in comparison to the stool antigen test. The increased risk of H. pylori infection associated with smoking and blood grouping
Simultaneous enrichment & on-line detection of low-concentration Copper, Cobalt, & Nickel Ions in Water by Near-Infrared diffuse reflectance spectroscopy combined with chemometrics
Sensitive detection of heavy metal ions in water is of great importance considering the effects that heavy metals have on public health. A developed fluidized bed enrichment technique was used to concentrate and detect low concentrations of Cu2+, Co2+, and Ni2+ in water samples by near-IR diffuse reflectance (NIDR) spectroscopy (NIDRS) directly without using any chemicals or reagents. The NIDR spectra of adsorbent were measured on-line, and quantitative detection was achieved by applying a built partial least-squares chemometric model. Sensitivity and accuracy was improved significantly because large-volume mixture solutions were used in the enrichment process. Root mean square error of cross-validation values for Cu2+, Co2+, and Ni2+ were 0.29, 0.41, and 0.35 μg/mL, respectively, with mean relative error values in the acceptable range of 6.56-10.27%. This study confirms the potential application of fluidized bed enrichment combined with NIDRS and chemometrics for the simultaneous detection of trace heavy metal ions in water, with low relative error
Altered Immune Responses in Mice After Receiving Nicotine-pulsed Mesenchymal Stem Cell-conditioned Medium
Introduction: Previous investigations have documented that nicotine-pulsed mesenchymalstem cells (MSCs) can induce an anti-inflammatory phenotype in some immune cells in vitro.This study aimed to assess the effects of nicotine-pulsed MSCS in the function of immunecells, macrophages, and lymphocytes of mice receiving these cels.Materials and Methods: Bone marrow-derived MSCs (1.5×106) were seeded in a T75flaskand incubated with 0, .1, .5, or 1 μM nicotine until the cells reached 90% confluency.Afterwards, immunophenotyping change, vitality, concentration of TGF-β, IL-10, and IDOlevels of the MSC-conditioned medium were examined. Correspondent to in vitro results, theC57BL/6 mice intravenously received 400 μL of the conditioned medium of MSCs (CM),conditioned medium of nicotine (.5 μM)-pulsed MSCs (CMN), or medium. After 12 h, thelymphocytes, neutrophils, and peritoneal macrophages of the mice were isolated and theirfunction was evaluated ex vivo.Results: The least effective dose concentration of nicotine that led to an anti-inflammatoryenvironment by the MSC-conditioned medium was 0.5 μM. Nicotine at this concentrationprompted a higher level of TGF-β, IDO concentration in the conditioned medium. However,this concentration did not affect the MScs’ markers expressions or MScs’ vitality. T lymphocytesisolated from the mice receiving CMN showed a significant decrease in proliferation rate. Theratio of the IFN-γ gene expression to IL-4 gene expression in splenocytes was significantlyreduced in the mice receiving CMN compared to the mice receiving CM. The neutral reduptake, respiratory burst, and nitric oxide production of the peritoneal macrophage onlydecreased in the mice treated with CMN. These factors also decreased in neutrophils isolatedfrom mice receiving CM or CMN. However, these decreases were more prominent in the micetreated with CMN.Conclusion: Treatment of MSCs by nicotine may be a promising strategy to enhance theimmunomodulatory properties of these cells
Investigation of the nanocrytalline SnO2 Synthesized by Homogeneous Precipitation
Nanocrystalline tin dioxide synthesized by the homogeneous pre cipitation method using the reaction of tin tetrachloride pentahydrate and urea solutions has been investigated. The nanocrystalline powder has been traced at different calcination temperatures (300ºC-1050ºC), and then characterized by using   Thermogravemetric analysis, differential thermal analysis and x-ray diffraction. The microstructure of the obtained nanoparticles has been examined by scanning and transmission electron microscopy. The average crystallite size, determined by x-ray diffraction, was found to be in the range of 3 –30 nm. The analysis exhibited a tetragonal phase. Optical properties were investigated by a UV–vis absorption spectrophotometer. The calculated optical band gap lies between 4.47–3.71 eV as a result of increasing the calcination temperatures and crystallite size. Surface area and porosity of SnO2 nanoparticles are measured. Specific surface area which is related to pore volume and decreases from 155 m2/g at 100ºC to 3.3 m2/g at 1050ºC.Â
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