فهرست مطالب sajjad keshipour

Pseudomonas aeruginosa is one of the most important opportunistic pathogens in humans and animals. Natural antibacterial compounds like propolis are the best substitute for antibiotics. The aim of this study was to evaluate the antibacterial effect of Ethanolic extract of propolis, propolis nanoemulsion, and their combinations with ciprofloxacin in the treatment of experimental wound infection contaminated with Pseudomonas aeruginosa in rabbits. Propolis was obtained from a different region of Western Azerbaijan in the year 2018. Then the ethanol extract of propolis was prepared. And so, nanoemulsion of propolis was prepared. The broth microdilution method was used to determine the MIC of propolis and propolis nanoemulsion on P. aeruginosa. 28 rabbits used in 7 groups: Negative control (CO), Tween 20 (T), extract of propolis (P), nanoemulsion of propolis (NP), ciprofloxacin (C), ciprofloxacin+ extract of propolis (C + P), ciprofloxacin + nanoemulsion of propolis (C + NP). Full-thickness skin wound was created under general anesthesia and bacterial suspension (108 CFU/ml) was inoculated to each wound site. Macroscopic and microscopic characteristics and Superficial bacterial load of wounds were studied on days 7, 14, and 21. The number of bacteria in treatment groups was significantly lower than in negative control groups (p < 0.05). The macroscopic evaluation of wounds showed that C+P and C+NP enhanced wound closure in comparison with the negative control group and ciprofloxacin (p < 0.05). Histopathology assessment of the wound showed that the combination of C+P, and C+NP had a better and faster healing effect than the other groups, however, its difference was significant only when compared to CO, C, and T groups (p < 0.05). The results of the present study showed that a combination of ciprofloxacin + ethanolic extract of propolis and ciprofloxacin + propolis nanoemulsion had better therapeutic effects than either agent alone.

Hydrogen has been considered as one of the worthy fuels for the high potential energy and nonpolluting combustion. With increasing the concerns about fossil fuels pollution for the environment, attempts have been concentrated on the improving of new green fuels such as hydrogen. Particularly, the safe and cost-effective production of hydrogen has been widely studied, in which the catalysts deserved remarkable progresses. Herein, photocatalytic activity of cobalt-phthalocyanine/graphene quantum dots/TiO2 was investigated in the formic acid degradation under visible irradiation toward hydrogen generation. TiO2 as a semiconductor trapped photons to generate electron/hole pairs and graphene quantum dots made delay in their recombination to provide long time for promoting the hydrogen and carbon dioxide evolution reactions by electrons/holes. Cobalt (II)-phthalocyanine as a catalyst utilized the electrons in the transformation of protons to H2, while in the positive region carbon dioxide was producing. The reaction was progressed efficiently affording H2 with the rate of 3.60 mmol.h-1 and activation energy was calculated to be 16 KJ.mol-1. This three-component catalyst showed satisfying stability to run the reaction for long time. Notable catalytic activity, and employing light power for the reaction done are two significant characteristics of this hybrid.

While one of the valuable approaches to obtaining a heterogeneous catalyst is supporting them on a high surface area supports, the strategy mainly suffers from the low number of chelating agents on most of the supports to grip the metal cations catalysts. Therefore, loading multidentate compounds susceptible to binding with metal cations is a potent strategy to improve the catalyst stability on the support. In this report, metformin as a multi-dentate ligand was bonded onto graphene quantum dots as a high aspect ratio compound to afford new support susceptible to chelating Co(II). Deposition of Co(II) on graphene quantum dots modified with metformin gave a new sustainable heterogeneous catalyst that was highly active in the oxidation of alkyl arenes. The reactions were performed in solvent-free conditions at 80 ºC with high conversions up to 96%. The organometallic compound is applicable as a recoverable heterogeneous catalyst with recyclability up to 6 times. The modification of graphene quantum dots with metformin also can gain more attention from medicinal researchers.

In this research, graphene oxide (GO) was functionalized with D-penicillamine (DPA) and used to develop an electrochemical sensor for Cu(II) cation. For the successful synthesis of D-penicillamine-functionalized graphene oxide (DPA-GO), Fourier Transfer Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), X-ray diffraction pattern (XRD), and Transmission Electron Microscopy (TEM) are used. DPA-GO modified glassy carbon electrode (DPA-GO / GCE) was prepared and its electrochemical behavior was studied in the presence of Cu(II) cations by cyclic voltammetry, and the results showed the better performance of the DPA-GO-modified electrode compared to unmodified and GO-modified electrode, which related to GO nanostructure and complexing ability of sulfur, nitrogen, and oxygen-containing functional groups in the DPA structure. The prepared sensor was used for the selective and sensitive measurement of Cu(II) cations by square-wave anodic stripping voltammetry (SW-ASV) and the factors affecting the sensor performance were investigated and optimum conditions for sensor operation were determined. Under the optimal conditions, the prepared electrode has a linear response in the range of 1 pM to 0.1 µM and its detection limit was 0.31 pM. The proposed sensor was used satisfactorily to measure copper cation in real water samples with suitable reproducibility and stability.

This study aimed to evaluate the thermal stability and monomer elution of bulk fill composite resins cured at different irradiation distances.

Forty cylindrical-shaped (3×4mm) specimens were fabricated from two composite resins (X-tra fil, X-tra base) and cured from 0 and 7mm distances. In 9 specimens, the degree of conversion was determined by the release of monomers. For this purpose, after curing of composites, they were immersed in 5 mL of 99.9% methanol and stored at 37°C for 24h. The eluted monomer was then analyzed by gas chromatography (GC). Also, thermal stability of one sample from each group was assessed by thermogravimetric analysis (TGA) at a rate of 10°C/min. Data were analyzed using two-way ANOVA and Tukey’s post-hoc test (P<0.05).

X-tra fil had significantly higher degree of conversion than X-tra base (P=0.001). Specimens cured at 7mm distance had significantly lower degree of conversion compared with those cured at 0 mm distance (P=0.001). The interaction effect of composite type and distance of light curing unit from the surface of samples was statistically significant (P=0.001). Regarding the TGA results, the lowest and the highest percentages of weight loss were detected in X-tra fil cured at 0 mm distance and X-tra base cured at 7mm distance, respectively.

X-tra fil composite cured at 0mm distance had the highest degree of conversion and thermal stability, and X-tra base composite cured at 7mm distance had the lowest values.

Esterification reactions of some polyols and diols were investigated in the presence of SnO2 and nano-SnO2 and the results were compared with the catalyst-free conditions. High conversions were obtained for most of the reactions in the presence of SnO2 and nano-SnO2 which shows the high catalytic activity of SnO2 and nano-SnO2 for the esterification reaction. Low cost of the catalysts compared to alkyl tins, high safety compared to protic acids such as sulfuric acid and high chemical and thermal stability of the catalysts make the reactions interesting for the large-scale production of various polyol esters. Due to the important role of the polyol esters in various industries especially in the lubricant industry, the introduced approach can be interesting.

Chitosan was used as a green support for cobalt(II). Chitosan-cobalt(II) after characterization with common methods including FT-IR, flame atomic absorption spectroscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and thermal gravimetric analysis as a biocompatible heterogeneous catalyst was used in the oxidation reaction of styrene to styrene oxide. The reaction led to the formation of styrene oxide in the presence of the prepared catalyst and excess amounts of hydrogen peroxide as a green oxidant in H2O as the solvent at room temperature during 6 h with 96% yield and high selectivity. Also, the reaction gave high yield in the solvent free conditions. The catalyst is recyclable for six times without any significant decreases in the activity.

Pd and Co nanoparticles were deposited on cellulose for use as a heterogeneous catalyst in the bimetallic catalytic reduction reaction. The catalyst was characterized with Energy Dispersive X-Ray Spectroscopy, X-Ray Diffraction pattern, Thermal Gravimetric Analysis, Flame Atomic Absorption Spectroscopy, and Transmission Electron Microscopy, and applied in the reduction reaction of nitroaromatics using NaBH4 at room temperature. Aromatic amines were obtained as the sole product of the reduction reaction during 2h. This reaction has some advantages such as mild reaction conditions, high yield, green solvent, and recyclable catalyst. Also, the recovered catalyst is applicable in the reduction reaction for 4 times without a significant decrease in the activity.

Objective- The healing effect of chitosan supported cerium oxide nanoparticles (nano-CeO2) on cutaneous experimental excisional wound infected with pseudomonas aeruginosa was studied in rat.
Design- Experimental Study.
Animals- Sixty male albino rats.
Procedures- The chitosan supported nano-CeO2 hydrogel was prepared and characterized using Fourier-transform infrared spectroscopy (FT-IR), Energy Dispersive X-ray Spectroscopy (EDX), X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The wound was infected with p. aeruginosa and in positive control (PC) group it was treated with silver sulfadiazine ointment with no treatment in negative control (NC) group. The infected wound was treated with chitosan suspension-gel, cerium oxide nanoparticles solution or chitosan supported-CeO2 nanoparticle gel in the treatment groups. The rats were randomized into five groups (n=12). Each group was subdivided into three subgroups of four animals each and studied 3, 7 and 14 days post-wounding.
Results- Plantimetry, histopathological assessments and hydroxyprolin content showed better and faster healing of the wounds in the treatment groups, particularly in chitosan supported-CeO2 nanoparticle gel (ChCe) group compared to the NC group (PConclusion and Clinical Relevance-Topical application of the chitosan supported nano-CeO2 particles on the infected wound enhanced tissue total antioxidant capacity, reduced the bacterial count, accelerated proliferation and migration of fibroblasts and keratinocytes, increased hydroxyproline level and neovascularization scale of the healing wound. Chitosan supported nano-CeO2 hydrogel could be suggested as an alternative therapy for treating of the infected wound.

A new bimetallic nanocomposite of chitosan was prepared. Pd and Co nanoparticles were deposited on chitosan to produce a new heterogeneous recyclable catalyst for use in the bimetallic catalytic reduction reaction. The catalyst was characterized with common analysis methods for nanocomposites including Energy Dispersive X-Ray Spectroscopy, X-Ray Diffraction pattern, Thermal Gravimetric Analysis, Flame Atomic Absorption Spectroscopy and Scanning Electron Microscopy, and applied in the reduction reaction of nitroaromatics using NaBH4 at room temperature. The bimetallic system gave good results compared to each of the applied metals. Various aromatic amines and diamines were used in the reduction reaction. The aromatic amines were obtained as the sole product of the reduction reaction with 15 mol% Pd and 12 mol% Co during 2h. This reaction had some advantages such as mild reaction conditions, high yield, green solvent, and a recyclable catalyst. Also, the recovered catalyst was applicable in the reduction reaction without a significant decrease in the activity for up to six times.