An optimization of process parameters for deep desulfurization of model fuel by ZSM-5/ZnO photocatalyst using response surface method

One of the major factors that causes air pollution are sulfur oxides) SO_x) that exiting from vehicles exhaust by combustion of fossil fuel. Although hydrodesulfurization method has always been the option in oil refineries to reduce sulfur contents, but it is almost impossible to meet stringent new environmental regulation by this method. The Achilles heel of the conventional method is weakness in removing aromatic sulfur recalcitrant compounds. In the present research, photocatalytic oxidative desulfurization (PhOD) based on the ZSM-5/ZnO catalyst is developed. n-Decane as the model fuel and benzothiophene (BT) and dibenzothiophene (DBT) as the sulfur compounds are used. Then by the response surface method the optimum conditions were developed. The result indicates that catalyst with 6%wt Zn/ZnO, 45 min reaction time, UV power of 32 watts and catalyst to fuel ratio of 2 gr/L is able to remove BT and DBT with efficiency of 86.1% and 74.0%, respectively.     

Partitioned solution of an unsteady adjoint for strongly coupled fluid-structure interactions and application to parameter identification of a one-dimensional problem

Unsteady fluid-structure interaction (FSI) simulations are generally time-consuming. Gradient-based methods are preferred to minimise the computational cost of parameter identification studies (and more in general optimisation) with a high number of parameters. However, calculating the cost function’s gradient using finite differences becomes prohibitively expensive for a high number of parameters. Therefore, the adjoint equations of the unsteady FSI problem are solved to obtain this gradient at a cost almost independent of the number of parameters. Here, both the forward and the adjoint problems are solved in a partitioned way, which means that the flow equations and the structural equations are solved separately. The application of interest is the identification of the arterial wall’s stiffness by comparing the motion of the arterial wall with a reference, possibly obtained from non-invasive imaging. Due to the strong interaction between the fluid and the structure, quasi-Newton coupling iterations are applied to stabilise the partitioned solution of both the forward and the adjoint problem.     

Graphene-Assisted Synthesis of 2D Polyglycerols as Innovative Platforms for Multivalent Virus Interactions

2D nanomaterials have garnered widespread attention in biomedicine and bioengineering due to their unique physicochemical properties. However, poor functionality, low solubility, intrinsic toxicity, and nonspecific interactions at biointerfaces have hampered their application in vivo. Here, biocompatible polyglycerol units are crosslinked in two dimensions using a graphene-assisted strategy leading to highly functional and water-soluble polyglycerols nanosheets with 263 ± 53 nm and 2.7 ± 0.2 nm average lateral size and thickness, respectively. A single-layer hyperbranched polyglycerol containing azide functional groups is covalently conjugated to the surface of a functional graphene template through pH-sensitive linkers. Then, lateral crosslinking of polyglycerol units is carried out by loading tripropargylamine on the surface of graphene followed by lifting off this reagent for an on-face click reaction. Subsequently, the polyglycerol nanosheets are detached from the surface of graphene by slight acidification and centrifugation and is sulfated to mimic heparin sulfate proteoglycans. To highlight the impact of the two-dimensionality of the synthesized polyglycerol sulfate nanosheets at nanobiointerfaces, their efficiency with respect to herpes simplex virus type 1 and severe acute respiratory syndrome corona virus 2 inhibition is compared to their 3D nanogel analogs. Four times stronger in virus inhibition suggests that 2D polyglycerols are superior to their current 3D counterparts.     

Encapsulation of palladium nanoparticles by multiwall carbon nanotubes‐graft‐poly(citric acid) hybrid materials

Citric acid was polymerized onto the surface of functionalized multiwall carbon nanotubes (MWCNT‐COOH) and MWCNT‐graft‐poly(citric acid) (MWCNT‐g‐PCA) hybrid materials were obtained. Due to the grafted poly(citric acid) branches, MWCNT‐g‐PCA hybrid materials not only were soluble in water but also were able to trap water soluble metal ions. Reduction of trapped metal ions in the polymeric shell of MWCNT‐g‐PCA hybrid materials by reducing agents such as sodium borohydride led to encapsulated metal nanoparticles on the surface of MWCNT. Herein palladium nanoparticles were encapsulated and transported by MWCNT‐g‐PCA hybrid materials (MWCNT‐g‐PCA‐EPN) and their application as nanocatalyst toward Heck reaction in different conditions was investigated. The catalytic activity of palladium ions supported by MWCNT‐g‐PCA hybrid materials (MWCNT‐g‐PCA‐PdCl₂) toward Heck reactions is much more than for MWCNT‐g‐PCA‐EPN. Structure, characteristics and catalytic activity of synthesized systems was investigated using spectroscopy and microscopy methods. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Protein Tyrosine Phosphatase-1B (PTP-1B) Knockdown Improves Palmitate-Induced Insulin Resistance in C2C12 Skeletal Muscle Cells

Insulin resistance is the central defect in type 2 diabetes and obesity. During the development of insulin resistance a lipid accumulation is accompanied by increased PTP-1B expression in the muscle. The aim of this study was to examine the effects of PTP-1B knockdown on insulin signaling and insulin resistance in the presence or absence of palmitate in C2C12 skeletal muscle cells. A stable C2C12 cell line was established using short hairpin RNA (shRNA) to knockdown protein expression of PTP1B. Analysis of PTP-1B protein expression and phosphorylation and protein levels of IRS-1 and Akt were detected by western blot. The effects of PTP-1B knockdown on the glucose uptake was also measured in C2C12 cells. The stable C2C12 cell line harboring the PTP-1B shRNA showed 62% decrease in the PTP-1B protein levels. 0.5 mM palmitate significantly induced insulin resistance in both control (26%) and PTP-1B knockdown cells (16.5%) compared to the untreated cells. Under treatment with palmitate, insulin stimulated phosphorylation of IRS-1 (Tyr632) and Akt (Ser473) in knockdown cells was significantly 1.55- and 1.86-fold, respectively, greater than the controls. In the presence of palmitate, insulin dependent glucose uptake was significantly about 3-fold higher in PTP-1B knockdown stable C2C12 cells compared to the control cells. Our data showed that decreasing the PTP-1B protein level by shRNA can enhance the activity of important elements of insulin signaling. The improvement in insulin action persisted even in palmitate treated insulin resistant myotubes.     

Estimation of sweet cherry antioxidant activity and anthocyanin content during ripening by artificial neural network–assisted image processing technique

This paper presents a new approach for estimating antioxidant activity and anthocyanin content at ripening stages of sweet cherry by combining image processing and artificial neural network (ANN) techniques. The system was consisted of a CCD camera, fluorescent lights, capture card and MATLAB software. Anthocyanin content and antioxidant activity were determined by pH differential and 2, 2‐diphenyl‐1‐picrylhydrazyl methods, respectively. It was found that anthocyanin content was constantly increased during ripening stages, and antioxidant activity decreased during the early stages of development but increased from stage five. Several ANN models were designed and tested. Among these networks, a two hidden layer network with 11‐6‐20‐1 architecture had the highest correlation coefficient (R = 0.965) and the lowest value of mean square error (MSE) (215.4) for modelling anthocyanin content. Similarly, a two hidden layer network with 11‐14‐9‐1 architecture had the highest correlation coefficient (R = 0.914) and the lowest value of MSE (0.070) for modelling antioxidant activity.     

Irbesartan‐loaded electrospun nanofibers‐based PVP K90 for the drug dissolution improvement: Fabrication,in vitro performance assessment,and in vivo evaluation

Irbesartan with a low bioavailability is known as a poorly water‐soluble drug. The purpose of this investigation is the improvement of physicochemical properties (such as solubility and dissolution rate) of Irbesartan using electrospun nanofibers‐based solid dispersion preparation. Nanofibers were prepared using certain weight ratios of the drug and polyvinylpyrrolidone K90 (PVP K90). Then, dissolution studies were carried out. Moreover, selected samples were examined by many different tests such as Fourier transform infra red (FTIR), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), high‐performance liquid chromatography (HPLC), and scanning electron microscopy (SEM). Though solubility and dissolution rate of all Irbesartan‐PVP nanofibers improved, but the best result was obtained through of ENSD5 (3% (w/v) : 7% (w/v)). In sink condition approximately 97% of this sample was released during 60 min. The drug content was among the different batches from 40.55 ± 1.01 to 245.32 ± 1.77 μg/mL. The maximum saturation solubility was belonged to this sample. According to the results of the thermal analysis and FTIR spectroscopy, there is no chemical reaction between drug and carrier, also samples has not changed during the process. Amorphous structure for nanofibers was confirmed by DSC thermograms and XRD diffractograms and morphological structure of samples were observed by SEM images. Ultimately, in vivo studies were performed in healthy grey rabbits and the results were satisfactory. The drug–polymer nanofibers showed an increase in relative bioavailability than the plain Irbesartan suspension. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42212.     

Quantum dot-pseudopolyrotaxane supramolecules as anticancer drug delivery systems

Pseudopolyrotaxanes (Ps-PR) consisting of α-cyclodextrin rings, polyethylene glycol axes and end triazine groups were synthesized and characterized. Dissociation of the α-cyclodextrin rings from the polyethylene glycol axes was avoided by the host-guest relationship between its end triazine groups and β-cyclodextrins conjugated onto the surface of quantum dots (β-CD-graft-QDs), leading to a new type of the dynamic polyrotaxanes in which QDs play the role of stoppers noncovalently. Stability of the synthesized supramolecules was depended on the efficiency of the host-guest relationships between the end triazine groups of Ps-PR and β-CD-graft-QDs through which release of α-cyclodextrin rings from the polyethylene glycol axes was controlled.To prove the efficacy of the synthesized supramolecules as drug delivery systems (DDSs) cisplatin (Cis-Diamminedichloroplatinum (CDDP) a platinum-based chemotherapy drug) and folic acid as a tumor-recognition module were conjugated to their stoppers and they were subjected to the receptor-mediated endocytosis and release inside the cancer cells, murine colon adenocarcinoma tumor C26. Then, it was proved that these tumor-targeting DDSs are promising systems for future cancer therapy. Rate of the release of the drugs, conjugated to the functional groups of stoppers was also investigated.     

PITTING CORROSION OF SAF2205 DUPLEX STAINLESS STEEL IN ACETIC ACID CONTAINING BROMIDE AND CHLORIDE

Development of duplex stainless steels has been linked strongly with the increasing requirements of the industry for resistance of materials to highly aggressive environments. In the present work, the effects of bromide and chloride ion concentrations and temperature on the pitting corrosion of commercial grade SAF2205 duplex stainless steel were studied. Cyclic polarization and scanning electron microscopy (SEM) techniques were used to study the pitting corrosion behavior of this steel in 80%v/v acetic acid solution containing 0.01, 0.1, 0.2, and 0.5 M sodium bromide and sodium chloride, respectively. Pitting potential was found to decrease with the increase of the temperature and bromide ion concentration. In the presence of chloride ions, pitting corrosion was not observed at room temperature. Critical pitting temperature in chloride-containing solutions was estimated to be above 35°C. In the case of pitting, SEM observation revealed that pit initiation is in the austenite phase regions.