Photocatalytic degradation of bromophenol blue in aqueous medium using chitosan conjugated magnetic nanoparticles

Three different chitosan conjugated magnetic nanoparticles (CCMN) of Co, Ni and Fe were prepared using co-precipitation method. The prepared CCMN were characterized by scanning electron microscopy (SEM), Xray diffraction (XRD) and Fourier transform infra-red (FT-IR) spectroscopic techniques. The SEM results showed a smooth surface morphology with almost uniform particle size and irregular shape structure for all CCMN. The XRD study revealed the crystalline structure in case of Co-CCMN and Ni-CCMN, while amorphous nature of Fe-CCMN was observed. The particle size of the prepared CCMN was found to be <95 nm, as confirmed from SEM and XRD analyses. Similarly, FT-IR analysis showed the incorporation and conjugation of Co, Ni and Fe magnetic nanoparticles into the chitosan polymer matrix. The point of zero charge (PZC) was found to be 7.41 for Co-CCMN and Ni-CCMN and 7.70 for Fe-CCMN. The photocatalytic activity of the prepared CCMN was investigated under UV light irradiation (254 nm and 15 W) in the aqueous medium using bromophenol blue (BPB). The photocatalytic process was monitored by UV-visible spectrophotometer for different irradiation times (0 to 10 h). The results showed that all the prepared CCMN displayed good to excellent photocatalytic property where the highest degradation was exhibited by Fe-CCMN (94.5%), followed by Co-CCMN (85.1%) and Ni-CCMN (83.0%). The prepared catalysts were recycled and reused, maintaining good photocatalytic activity for four consecutive batches.     

Biomathematical study of non‐Newtonian nanofluid in a diverging tube

The present article deals with the peristaltic ?ow of a nano‐Eyring Prandtl ?uid model in a diverging tube. The governing equations for the considered model in view of the nanoparticles are presented in cylindrical coordinates using long wavelength and low Reynolds number approximation. The resulting nonlinear di?erential equations are solved for velocity, temperature, nanoparticle, and pressure gradient using the homotopy perturbation method. Numerical integration has been carried out for pressure rise, frictional forces, velocity, temperature, and nanoparticles. The numerical results are discussed through graphs. The e?ects of various emerging parameters are investigated for ?ve di?erent peristaltic waves. Streamlines have been plotted at the end of the article for the considered waveforms. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21047     

Production of mixed methyl/ethyl esters from waste fish oil through transesterification with mixed methanol/ethanol system

Biodiesel (mixed fatty acid methyl/ethyl esters) was prepared from waste fish oil through base-catalyzed transesterification with mixed methanol/ethanol system. Effect of methanol/ethanol (% v/v), type and concentration of the catalyst, mixed alcohols to oil molar ratio, the reaction temperature, and the reaction time on the biodiesel yield was optimized. Maximum biodiesel yield (97.30?wt%) was produced by implementing 1:1 methanol/ethanol (v/v), 1.0?wt% KOH, 6:1 mixed alcohols to oil molar ratio, 40°C reaction temperature, and 30?min of reaction time. Conversion of the waste fish oil to mixed methyl/ethyl esters was confirmed by ¹H NMR spectroscopy. Fuel properties of the resulting biodiesel in addition to its blends with petrodiesel were in good agreement with specifications of ASTM D6751 and ASTM D7467, respectively. Therefore, it was concluded that using mixed alcohol system for biodiesel production could reduce the production cost through reducing conditions required for maximum conversion.     

ROS/TNF-α Crosstalk Triggers the Expression of IL-8 and MCP-1 in Human Monocytic THP-1 Cells via the NF-κB and ERK1/2 Mediated Signaling

IL-8/MCP-1 act as neutrophil/monocyte chemoattractants, respectively. Oxidative stress emerges as a key player in the pathophysiology of obesity. However, it remains unclear whether the TNF-α/oxidative stress interplay can trigger IL-8/MCP-1 expression and, if so, by which mechanism(s). IL-8/MCP-1 adipose expression was detected in lean, overweight, and obese individuals, 15 each, using immunohistochemistry. To detect the role of reactive oxygen species (ROS)/TNF-α synergy as a chemokine driver, THP-1 cells were stimulated with TNF-α, with/without H₂O₂ or hypoxia. Target gene expression was measured by qRT-PCR, proteins by flow cytometry/confocal microscopy, ROS by DCFH-DA assay, and signaling pathways by immunoblotting. IL-8/MCP-1 adipose expression was significantly higher in obese/overweight. Furthermore, IL-8/MCP-1 mRNA/protein was amplified in monocytic cells following stimulation with TNF-α in the presence of H₂O₂ or hypoxia (p ˂ 0.0001). Synergistic chemokine upregulation was related to the ROS levels, while pre-treatments with NAC suppressed this chemokine elevation (p ≤ 0.01). The ROS/TNF-α crosstalk involved upregulation of CHOP, ERN1, HIF1A, and NF-κB/ERK-1,2 mediated signaling. In conclusion, IL-8/MCP-1 adipose expression is elevated in obesity. Mechanistically, ROS/TNF-α crosstalk may drive expression of these chemokines in monocytic cells by inducing ER stress, HIF1A stabilization, and signaling via NF-κB/ERK-1,2. NAC had inhibitory effect on oxidative stress-driven IL-8/MCP-1 expression, which may have therapeutic significance regarding meta-inflammation.     

Selective Mobile Communication in Socially Sensitive Environments

In certain environments, the use of mobile phones must be curtailed for the sake of security or out of respect for others. We present a novel method for selectively controlling mobile phone services in such areas using a base station controller and a sequence of detection steps to identify when the mobile device is within the coverage area. A prototype for the method has been developed using commercial off-the-shelf and custom designed hardware and software subsystems. Key components in the prototype system are two directional antennas located at the entry to the controlled area with one antenna facing outwards and the other inwards. By using the proposed detection method, the base station controller is able to detect when a mobile station enters or leaves the controlled area. Experiments using a variety of detection sequences by the two directional antennas and associated white- and blacklists of allowable and disallowed devices, respectively, confirm that the prototype system is able to effectively control the use of mobile devices within the coverage area.     

Discriminating protein structure classes by incorporating Pseudo Average Chemical Shift to Chou's general PseAAC and Support Vector Machine

Proteins control all biological functions in living species. Protein structure is comprised of four major classes including all-α class, all-β class, α+β, and α/β. Each class performs different function according to their nature. Owing to the large exploration of protein sequences in the databanks, the identification of protein structure classes is difficult through conventional methods with respect to cost and time. Looking at the importance of protein structure classes, it is thus highly desirable to develop a computational model for discriminating protein structure classes with high accuracy. For this purpose, we propose a silco method by incorporating Pseudo Average Chemical Shift and Support Vector Machine. Two feature extraction schemes namely Pseudo Amino Acid Composition and Pseudo Average Chemical Shift are used to explore valuable information from protein sequences. The performance of the proposed model is assessed using four benchmark datasets 25PDB, 1189, 640 and 399 employing jackknife test. The success rates of the proposed model are 84.2%, 85.0%, 86.4%, and 89.2%, respectively on the four datasets. The empirical results reveal that the performance of our proposed model compared to existing models is promising in the literature so far and might be useful for future research.     

Elastic Properties of UHMWPE-SWCNT Nanocomposites’ Fiber: An Experimental, Theoretic, and Molecular Dynamics Evaluation

Ultrahigh molecular weight polyethylene (PE) filaments were reinforced with 2 wt.% of single-walled carbon nanotubes (SWCNTs). The solution spinning method was used to produce both neat and reinforced PE filaments. Tensile tests and strain hardening through repeated loading-unloading cycles of the filaments revealed a spectacular contribution of the SWCNTs in enhancing the elastic properties, e.g., strength and modulus. The theoretic strength and modulus of the reinforced PE were predicted using the shear lag model and micromechanics-based model, respectively, and verifying with experimental results. It was observed that the predicted strength and modulus were comparable only with those obtained after strain hardening. In the next step, a molecular dynamic simulation was conducted by simulating a unit cell containing a SWCNT surrounded by PE matrix subjected to uniaxial tensile strain. The strength and modulus of the simulated structure showed an agreement, to certain extent, with experimental observations of strain-hardened nanocomposites.