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... 

Platelet lysate (PL), a blood product that contains high concentrations of growth factors (GFs), can be considered as a cost-effective source of multiple GFs. In this study, hyaluronic acid (HA) based microgels were developed for delivery of PL proteins. Spherical microgel were prepared using a water in oil emulsion method. First, hyaluronic acid was grafted with tyramine groups, after which prepared microdroplets were crosslinked via an enzymatic reaction in the presence of hydrogen peroxide and horseradish peroxidase. Because of electrostatic interactions, these microgels are promising carriers for positively charged proteins entrapment like most of the GFs. When microgels are incubated in... 

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... 

FeVO4/CeO2 was applied in the electro-Fenton (EF) degradation of Methyl Orange (MO) as a model of wastewater pollution. The results of the characterization techniques indicate that FeVO4 with triclinic structure and face-centered cubic fluorite CeO2 maintained their structures during the nanocomposite synthesis. The effect of applied current intensity, initial pollutant concentration, initial pH, and catalyst weight was investigated. The MO removal reached 96.31% and chemical oxygen demand (COD) removal 70% for 60 min of the reaction. The presence of CeO2 in the nanocomposite plays a key role in H2O2 electro-generation as a significant factor in the electro-Fenton (EF) system. The metal... 

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... 

Novel molybdenum complex, cis-[MoO2(phox)2] has been synthesized and characterized by IR, 1H NMR, elemental analyses (CHN), and X-ray molecular structure determination methods. This complex was found to be an efficient, selective catalyst for the oxidation of various sulfides to sulfoxides with urea hydrogen peroxide (UHP) in excellent yields (100% for diallylsulfide) and short reaction times (20 min) at room temperature. The catalytic system oxidizes diallylsulfide chemoselectively to its corresponding sulfoxide without any over oxidation in double bond. © 2007 Elsevier B.V. All rights reserved  

Catalytic studies were performed to develop a simple oxidation system for olefins and sulfides using manganese(III)-tridentate Schiff base complex, Mn(N-OPh-sal)(acac)(EtOH) (N-HOPh-Hsal = N-hydroxyphenyl-salicyldienamine, Hacac = acetylacetone), and urea-hydrogen peroxide (UHP) as terminal oxidant. Conversions up to 90% for olefins at 0 °C and 96% for sulfides at room temperature as well as sulfoxide selectivity up to 73% were achieved in short reaction times. Also this study confirms the accelerating effect of strong π-donor axial ligands such as imidazole (ImH) on the oxidation reactions. © 2008 Elsevier B.V. All rights reserved  

Photo-oxidation of dyes is a new concern among researchers since it offers an attractive method for decoloration of dyes and breaks them into simple mineral forms. An advanced oxidation process, UV/H2O2, was investigated in a laboratory scale photoreactor for decolorization of the Reactive blue 19 (RB19 dye from synthetic textile wastewater. The effects of operating parameters such as hydrogen peroxide dosage, pH, initial dye concentration and UV dosage, on decolorization have been evaluated. The RB19 solution was completely decolorized under optimal hydrogen peroxide dosage of 2.5 mmol L-1 and low-pressure mercury UV-C lamps (55 w) in less than 30 min. The decolorization rate followed... 

In this work we present results of density functional theory (DFT) calculations on dicopper patellamides and their affinity for molecular oxygen and carbonate. Patellamides are cyclic octapeptides that are produced by a cyanobacterium, and may show promise as therapeutics. Thus, carbonate binding to a dicopper patellamide center gives a stable cyclic octapeptide with a twist of almost 90°. The system exists in close-lying open-shell singlet and triplet spin states with two unpaired electrons in orthogonal σ* orbitals on each metal center. Subsequently, we replaced carbonate with dioxygen and found a stable Cu2(μ-O)2 diamond shaped patellamide core. In this structure the original dioxygen... 

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  

Alcohols have been successfully converted into their corresponding carbonyl compounds using hydrogen peroxide catalyzed by lithium chloride on montmorillonite K10. Clay supported lithium chloride can be recovered after using as catalyst for oxidation of alcohols. The future runs according to this procedure showed no considerable decrease in the reaction yield and catalyst effect  

Hydroxylated aromatic compounds (HACs) are considered to be primary pollutants in a wide variety of industrial wastewaters. Horseradish peroxidase (HRP) is suitable for the removal of these toxic substances. However, development of a mathematical model and optimization of the HRP-based treatment considering the economical issues by novel methods is a necessity. In the present study, optimization of phenol removal from wastewater by horseradish peroxidase (HRP) was carried out using response surface methodology (RSM) and central composite design (CCD). As the initial experimental design, 2 4-1 half-fraction factorial design (H-FFD) is accomplished in triplicate at two levels to select the... 

This paper reports on the recovery of zinc, cobalt and manganese by two-step leaching of zinc-plants purification residue with sulfuric acid. The residue, hot filter press cake (HFC), contains 14 % ZnO, 4.8 % Co 3O4 and 22.9 % MnO. Effects of different parameters are determined and used to optimize the process. With acid to hot filter press cake (HFC) stoichiometry of 0.85, acid concentration of 30 g/L and temperature of 25°C, it took two minutes to separate zinc from zinc plant residue. Hydrogen peroxide (H2O2) was used as an oxidation agent. The most suitable acid concentration for leaching of both cobalt and manganese was 50 g/L. Recovery of cobalt and manganese increased with peroxide... 

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... 

Gelatin is a denatured protein derived from collagen by thermohydrolysis and has a rheological property of thermo reversible transformation between sol & gel. Gelatin is one of the most important biopolymers, with widespread applications in the food, pharmaceutical, cosmetic and photographic industries. Gelatin is commercially made from skins and skeletons of bovine and porcine and mammalian gelatin has been intensively studied. However, mammalian gelatin is at risk for contamination with bovine spongiform encephalopathy and increase in demand for kosher and halal foods have created a demand for fish gelatin for food applications. Therefore, the objective of this study was to extract gelatin... 

Herein, MIL-101(Fe), CoFe2O4, novel binary (MIL-101(Fe)/CoFe2O4, MIL-101(Fe)/GO and CoFe2O4/GO), and ternary (MIL-101(Fe)/CoFe2O4/(3%)GO and MIL-101(Fe)/CoFe2O4/(7%)GO) magnetic composites based upon the MIL-101(Fe) were synthesized. The XRD, FESEM, TEM, EDX, BET-BJH, FTIR, VSM, DRS, PL, EIS and other electrochemical analyses were applied to characterize samples. The MIL/CoFe2O4/(3%)GO demonstrated the best performance compared to other samples for visible light photocatalytic and photo-Fenton-like degradation of Direct Red 23 (DtR-23), Reactive Red 198 (ReR-198) dyes as well as Tetracycline Hydrochloride (TC-H) antibiotic. Degradation of dyes using the ternary composite after 70 min of... 

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...