Sharif Digital Repository

Cell survival during the early stages of transplantation and before new blood vessels formation is a major challenge in translational applications of 3D bioprinted tissues. Supplementing oxygen (O2) to transplanted cells via an O2 generating source such as calcium peroxide (CPO) is an attractive approach to ensure cell viability. Calcium peroxide also produces calcium hydroxide that reduces the viscosity of bioinks, which is a limiting factor for bioprinting. Therefore, adapting this solution into 3D bioprinting is of significant importance. In this study, a gelatin methacryloyl (GelMA) bioink that is optimized in terms of pH and viscosity is developed. The improved rheological properties... 

The adsorption and dissociation of H2O2 on small PdxM3-x (M=Pt, Cu; x = 1-3) clusters is investigated using the B3PW91 hybrid density functional method. Natural bond orbitals are analysed to obtain partial charges on atoms, dipole moments, bond orders, and hybrid orbitals of the PdxM3-x-H2O2 systems. The calculated adsorption energies are in the range of -0.32 to -2.12 eV. Generally, H2O2 adsorbs on top positions through one of its oxygen atoms and only in a few cases reacts with the cluster through both oxygen and hydrogen sides. In the latter case the cluster sites which are negatively charged interact with the hydrogen atoms. Interestingly, on the triplet Pd2Pt cluster, H2O2 dissociates... 

This study demonstrated the prolonged benefits of polyvinyl-coated calcium peroxide (PVA@CP) in Fe(II)/nFeS mediated Fenton-like reaction. PVA@CP was prepared by a coating of PVA on calcium peroxide (CP) and synthesized nano-sized iron sulfide (nFeS) was characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) with energy dispersive spectroscopy (EDS) elemental mapping, X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES) and Fourier transmission infrared (FTIR) techniques. Trichloroethylene (TCE) degradation in various oxic environments (H2O2, CP, or... 

This study demonstrated the prolonged benefits of polyvinyl-coated calcium peroxide (PVA@CP) in Fe(II)/nFeS mediated Fenton-like reaction. PVA@CP was prepared by a coating of PVA on calcium peroxide (CP) and synthesized nano-sized iron sulfide (nFeS) was characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) with energy dispersive spectroscopy (EDS) elemental mapping, X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES) and Fourier transmission infrared (FTIR) techniques. Trichloroethylene (TCE) degradation in various oxic environments (H2O2, CP, or... 

Oximes were oxidized to the corresponding carbonyl compounds in good to high yields by environmentally friendly and green oxidant, H2O2 catalyzed by montmorillonite K-10 supported cobalt(II) chloride. © 2007 Ali Ezabadi  

In the present work, an amperometric inhibition biosensor for the determination of sulfide has been fabricated by immobilizing Coprinus cinereus peroxidase (CIP) on the surface of screen printed electrode (SPE). Chitosan/acrylamide was applied for immobilization of peroxidase on the working electrode. The amperometric measurement was performed at an applied potential of -150. mV versus Ag/AgCl with a scan rate of 100. mV in the presence of hydroquinone as electron mediator and 0.1. M phosphate buffer solution of pH 6.5. The variables influencing the performance of sensor including the amount of substrate, mediator concentration and electrolyte pH were optimized. The determination of sulfide... 

In this work, Ag nanoparticles were loaded on ZIF-67 covered by graphene oxide (Ag/ZIF-67@GO), and its catalytic performance was studied for the heterogeneous activation of peroxymonosulfate (PMS) under visible-light. The catalyst surface morphology and structure were analyzed by FT-IR, XRD, XPS, DRS, FE-SEM, EDX, TEM, BET, ICP-AES and TGA analysis. The efficacy of PMS activation by the Ag/ZIF-67@GO under visible light was assessed by phenol degradation and E. coli inactivation. Phenol was completely degraded within 30 min by HO•, SO4•− and O2•− generated through the photocatalytic PMS activation. In addition, total E. coli inactivation was attained in 15 min that confirmed the highly... 

A novel binuclear iron(III)-salicylaldazine complex has been synthesized and characterized by various techniques such as IR and UV–Vis spectroscopy and X-ray crystallography. The catalytic oxidation of sulfides in the presence of the aforementioned complex was explored at room temperature using urea hydrogen peroxide (UHP) as an oxidant. Effects of different reaction conditions consisting catalyst and oxidant amount, solvent effect and reaction time on the catalytic activity and selectivity in the reaction of methylphenylsulfide oxidation has been surveyed. Perfect selectivity toward sulfoxide was achieved after 15 min in CH3CN by choice of a properly optimized reaction condition. © 2020... 

A five-coordinated Fe(III) complex with the distorted trigonal bipyramidal configuration was synthesized by reactions of FeCl36H2O and 2-(2′-hydroxyphenyl)oxazoline (Hphox) as a bidentate ON donor oxazoline ligand. Complex [Fe(phox)2Cl] was fully characterized, including by single-crystal X-ray structure analysis. DFT calculations were accompanied with experimental results in order to obtain a deeper insight into the electronic structure and vibrational normal modes of complex. Oxidation of sulfides to sulfoxides in one-step was conducted by this complex as catalyst using urea hydrogen peroxide (UHP) in mixture of CH2Cl 2/CH3OH (1:1) under air at room temperature. The results show that using... 

A novel glucose biosensor based on chromophore (silver nanoparticles) decolorizing for the photometric determination of glucose was developed. Silver nanoparticles are directly synthesized in the sol-gel matrix by a one-step method based on the reduction of the inorganic precursor AgNO3 and were used for the preparation, characterization and calibration of a highly sensitive and cost-effective localized surface plasmon resonance-based glucose biosensor. In the presence of glucose oxidase (GOx) and due to the enzyme-substrate (glucose) reaction, H2O2 was produced and silver nanoparticles in the sol-gel glass have the ability for the decomposition of hydrogen peroxide. Due to the degradation... 

Hydrogen peroxide readily oxidizes Hantzsch type 1,4-dihydropyridines in the presence of cobalt(II) acetate as catalyst at room temperature. No evidence of a dealkylation process for 4-alkyl 1,4-dihydropyridines has been observed  

Nano-sized particles of manganese oxides have been prepared by a very simple and cheap process using a decomposing aqueous solution of manganese nitrate at 100 °C. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction spectrometry have been used to characterize the phase and the morphology of the manganese oxide. The nano-sized manganese oxide shows efficient catalytic activity toward water oxidation and the epoxidation of olefins in the presence of cerium(iv) ammonium nitrate and hydrogen peroxide, respectively  

The catalytic activity of two manganese(III)-oxazoline complexes [Mn(phox)2(CH3OH)2]ClO4 and Mn(phox)3 (Hphox = 2-(2′-hydroxylphenyl)oxazoline), was studied in the epoxidation of various olefins. All of epoxidation reactions were carried out in (1:1) mixture of methanol:dichloromethane at room temperature using urea hydrogen peroxide (UHP) as oxidant and imidazole as co-catalyst. The epoxide yields clearly demonstrate the influence of steric and electronic properties of olefins, the catalysts and nitrogenous bases as axial ligand. [Mn(phox)2(CH3OH)2]ClO4 catalyst with low steric properties has higher catalytic activity than Mn(phox)3. The highest epoxide yield (95%) was achieved for indene... 

The reaction of Fe(acac)3 and 2-(2′-hydroxyphenyl)oxazoline (Hphox) as a bidentate O,N donor ligand afforded a six-coordinated iron(III) complex [Fe(phox)2(acac)] with distorted octahedral configuration. The complex was isolated as an air-stable crystalline solid and characterized by elemental analysis, FTIR, solution electrical conductivity, and by single-crystal X-ray structure analysis. The structure, electronic properties, and vibrational normal modes of the complex were investigated by DFT. The use of this complex as a catalyst for the oxidation of sulfides to their corresponding sulfoxides using urea hydrogen peroxide as the primary oxidant was investigated. The catalyst shows very... 

The efficient catalytic systems were investigated for the oxidation of various sulfide by manganese(III)-oxazoline complexes, [Mn(phox)2(MeOH)2]ClO4 and Mn(phox)3 (Hphox = 2-(2′-hydroxyphenyl)oxazoline). These complexes were found efficient catalysts for the oxidation of sulfides with urea hydrogen peroxide (UHP) in short reaction times (5 min) and under mild condition. Sulfoxides were obtained as the main products together with variable amounts of sulfones. The efficiency of the catalytic system was strongly influenced by the nature of solvents and axial ligands so the best yields were achieved in a mixture of methanol: dichloromethane and in the presence of imidazole as co-catalyst. © 2008... 

The catalytic wet peroxide oxidation (CWPO) of phenol with activated carbon (AC) as the catalyst has been successfully tested in a novel type of two-impinging-jets reactor (TIJR). The TIJR is characterized by a high-intensity reaction chamber, which is separated by a perforated plate from other parts of the reactor. The perforated plate was used as a filter to keep the catalyst particles within the reaction chamber. The influences of various operating and design parameters such as jet Reynolds number, feed flow rate, internozzle distance, and the jet diameter on the performance capability of the TIJR were investigated. As a result of the impinging process, turbulence, complex trajectory of... 

Overexpression of proteins/antigens and other gene-related sequences in the bodies could lead to significant mutations and refractory diseases. Detection and identification of assorted trace concentrations of such proteins/antigens and/or gene-related sequences remain challenging, affecting different pathogens and making viruses stronger. Correspondingly, coronavirus (SARS-CoV-2) mutations/alterations and spread could lead to overexpression of ssDNA and the related antigens in the population and brisk activity in gene-editing technologies in the treatment/detection may lead to the presence of pCRISPR in the blood. Therefore, the detection and evaluation of their trace concentrations are of... 

Watermelon seed oil characteristics were evaluated to determine whether this oil could be exploited as an edible oil. Hexane extraction of watermelon seeds produced yields of 50% (w/w) oil. The refractive index, saponification and iodine value were 1.4712 (at 25 °C), 200 mg KOH/g and 156 g I/100 g, respectively. The acid and peroxide values were 2.4 mg KOH/g and 3.24 mequiv/kg, respectively. The induction time of the oil was also 5.14 h at 110 °C, which was measured for the first time. Total unsaturation contents of the oil was 81.6%, with linoleic acid (18:2) being the dominant fatty acid (68.3%). Considering that the watermelon seed oil was highly unsaturated, the relatively high induction... 

In this study, a three-factor, three-level Box-Behnken design with response surface methodology were used to maximize the TOC removal and minimize the H2O2 residual in the effluent of the combined UV-C/H2O2-VUV system for the treatment of an actual slaughterhouse wastewater (SWW) collected from one of the meat processing plants in Ontario, Canada. The irradiation time and the initial concentrations of total organic carbon (TOCo) and hydrogen peroxide (H2O2o) were the three predictors, as independent variables, studied in the design of experiments. The multiple response approach was used to obtain desirability response surfaces at the optimum factor settings. Subsequently, the optimum...