Generalized Theory of Thermoviscoelasticity and a Half-Space Problem

In this work, the equations of generalized thermoviscoelasticity for a viscoelastic medium are derived. Also, uniqueness and reciprocity theorems for these equations are proved. In addition, a one-dimensional problem for a viscoelastic half space is considered. The Laplace transform technique is used to solve the problem. The solution in the transformed domain is obtained by a direct approach. The inverse transforms are obtained in an approximate analytical manner using asymptotic expansions valid for small values of time. The temperature, displacement, and stress are computed and represented graphically.     

Synthesis and application of polymer–clay nanocomposite‐supported dichromate oxidizing agent

A hybride polymer–clay nanocomposite supported dichromate reagents was prepared. Direct interaction of poly(styrene‐co‐N‐methyl‐4‐vinylpyridinium) iodide with sodium montmorillonite (MMT) through ion exchange between sodium cations in MMT and pyridinium ions in the copolymer afforded a polymer–clay nanocomposite (3). The resulting nanocomposite was reacted with potassium dichromate to form the nanocomposite‐supported reagents (4). The structure of the resulting nanocomposite was characterized by elemental analysis, infrared spectroscopy, X‐ray diffraction and transmission electron microscopy. The dispersion of the MMT particles in the polymer matrix was confirmed using scanning electron microscopy. X‐ray mapping for silicon in the nanocomposite revealed uniform distribution of Si in the polymer matrix. The effectiveness of these materials has been tested for oxidation of saturated primary, secondary and benzylic alcohols to their corresponding aldehydic and ketonic compounds in addition to oxidation of quinol to the corresponding quinone. Importantly, there is almost no formation of side‐product of this process. POLYM. COMPOS., 36:2066–2075, 2015. © 2014 Society of Plastics Engineer     

Impact of porosity and thickness of nano‐TiO2 films on the corrosion protection performance of C‐steel in H2SO4

The current study investigates the improvement in the corrosion protection performance of C‐steel after being dip‐coated with nano films from both pure TiO₂ and poly ethylene glycol (PEG) modified TiO₂. Characterization of the deposited TiO₂ films was performed by different techniques. Effect of morphology, porosity, and thickness of the deposited TiO₂ layers were also studied. Results revealed an increased corrosion protection of both coated TiO₂ films as compared to uncoated samples, with pure TiO₂ (without PEG) samples showing higher protection. Moreover, increasing the layer thickness of both types of TiO₂ coated films improved the protective properties.     

Detection of Schistosoma mansoni and Schistosoma haematobium by Real-Time PCR with High Resolution Melting Analysis

The present study describes a real-time PCR approach with high resolution melting-curve (HRM) assay developed for the detection and differentiation of Schistosoma mansoni and S. haematobium in fecal and urine samples collected from rural Yemen. The samples were screened by microscopy and PCR for the Schistosoma species infection. A pair of degenerate primers were designed targeting partial regions in the cytochrome oxidase subunit I (cox1) gene of S. mansoni and S. haematobium using real-time PCR-HRM assay. The overall prevalence of schistosomiasis was 31.8%; 23.8% of the participants were infected with S. haematobium and 9.3% were infected with S. mansoni. With regards to the intensity of infections, 22.1% and 77.9% of S. haematobium infections were of heavy and light intensities, respectively. Likewise, 8.1%, 40.5% and 51.4% of S. mansoni infections were of heavy, moderate and light intensities, respectively. The melting points were distinctive for S. mansoni and S. haematobium, categorized by peaks of 76.49 ± 0.25 °C and 75.43 ± 0.26 °C, respectively. HRM analysis showed high detection capability through the amplification of Schistosoma DNA with as low as 0.0001 ng/µL. Significant negative correlations were reported between the real-time PCR-HRM cycle threshold (Ct) values and microscopic egg counts for both S. mansoni in stool and S. haematobium in urine (p < 0.01). In conclusion, this closed-tube HRM protocol provides a potentially powerful screening molecular tool for the detection of S. mansoni and S. haematobium. It is a simple, rapid, accurate, and cost-effective method. Hence, this method is a good alternative approach to probe-based PCR assays.     

Design and Synthesis of Benzene Homologues Tethered with 1,2,4-Triazole and 1,3,4-Thiadiazole Motifs Revealing Dual MCF-7/HepG2 Cytotoxic Activity with Prominent Selectivity via Histone Demethylase LSD1 Inhibitory Effect

In this study, an efficient multistep synthesis of novel aromatic tricyclic hybrids incorporating different biological active moieties, such as 1,3,4-thiadiazole and 1,2,4-triazole, was reported. These target scaffolds are characterized by having terminal lipophilic or hydrophilic parts, and their structures are confirmed by different spectroscopic methods. Further, the cytotoxic activities of the newly synthesized compounds were evaluated using in vitro MTT cytotoxicity screening assay against three different cell lines, including HepG-2, MCF-7, and HCT-116, compared with the reference drug Taxol. The results showed variable performance against cancer cell lines, exhibiting MCF-7 and HepG-2 selectivities by active analogs. Among these derivatives, 1,2,4-triazoles 11 and 13 and 1,3,4-thiadiazole 18 were found to be the most potent compounds against MCF-7 and HepG-2 cancer cells. Moreover, structure–activity relationship (SAR) studies led to the identification of some potent LSD1 inhibitors. The tested compounds showed good LSD1 inhibitory activities, with an IC₅₀ range of 0.04–1.5 μM. Compounds 27, 23, and 22 were found to be the most active analogs with IC₅₀ values of 0.046, 0.065, and 0.074 μM, respectively. In addition, they exhibited prominent selectivity against a MAO target with apparent cancer cell apoptosis, resulting in DNA fragmentation. This research provides some new aromatic-centered 1,2,4-triazole-3-thione and 1,3,4-thiadiazole analogs as highly effective anticancer agents with good LSD1 target selectivity.     

Fatigue life prediction of composite materials using polynomial classifiers and recurrent neural networks

Due to their massively parallel structure and ability to learn by example, artificial neural networks can deal with nonlinear problems for which an accurate analytical solution is difficult to obtain. These networks have been used in modeling the mechanical behavior of fiber-reinforced composite materials. Although promising results were obtained using such networks, more investigation on the appropriate choice of their structure and their performance in the presence of limited and noisy data is needed. On the other hand, polynomials networks have been known to have excellent properties as classifiers and are universal approximators to the optimal Bayes classifier. Not being dependant on various user defined parameters, having less computational requirements makes their use over other methods, such as neural networks, an advantage.

In this work, the fatigue behavior of unidirectional glass fiber/epoxy composite laminae under tension–tension and tension–compression loading is predicted using feedforward and recurrent neural networks. These predictions are compared to those obtained using polynomial classifiers. Experimental data obtained for fiber orientation angles of 0°, 19°, 45°, 71° and 90° under stress ratios of 0.5, 0 and –1 is used.

It is shown that, even when a small number of experimental data points is used to train both polynomial classifiers and neural networks, the predictions obtained are comparable to other current fatigue life-prediction methods. Also, polynomial classifiers are shown to provide accurate modeling between the input parameters (maximum stress, R-ratio, fiber orientation angle) and the number of cycles to failure when compared to neural networks.     

Synthesis,microstructural investigation and compaction behavior of Al0.3CrFeNiCo0.3Si0.4 nanocrystalline high entropy alloy

This research article focused on developing Al_0.3CrFeNiCo_0.3Si_0.4 nanocrystalline high-entropy alloy (HEA) by mechanical alloying. The initial powders mixture was ball milled for 1 hr (HEA-1 h), 5 hr (HEA-5 h), 15 hr (HEA-15 h) and 25 hr (HEA-25 h) at ball to powder mass ratio (BPR) of 15:1 and a speed of 300 rpm. The mechanical alloying time was varied from 1 to 25 hr to ensure the nanocrystalline nature and attainment of steady state in HEA powders. The structure of the developed HEAs was characterized by means of X-ray diffraction (XRD), Laser particle size analyzer (LPSA), and various electron microscopes (TEM and FEGSEM with EDS). HEA-25hr sample exhibited the crystallite size of 13.8 nm with lattice strain of 0.67% obtained from XRD which matched the result by TEM. The formation of a solid solution (SS) with a uniform elemental dispersion was observed with a major BCC stable structure and a minor FCC structure in HEA-25 h sample. The HEA-25 h sample revealed an average particle size of 386.2 nm (89.8% peak intensity) with Polydispersity Index (PDI) value of 0.364 which confirmed the uniform distribution of particles over a narrow range of particle size. The synthesized powders were consolidated to green compacts with a loading rate of 1 mm/min at different compaction pressures (25, 50, 75, 100, 150, 200, 400, 600, 800, 1000, and 1100 MPa) for examining the powder particles packing. Several compaction models (both linear and non-linear) were discussed to establish the density-pressure relationship of developed HEAs. The results revealed that the milling time has influenced the relative density. HEA-1 h sample was exhibited the relative density of 0.76 whereas HEA-25 h sample was produced the relative density of 0.6 indicating more strength and more amount of strain hardening occurs in MAed HEA-25 sample in addition to the entropy effect for the same composition.     

MR-based assessment of vascular morphology and function

Initially, time-of-flight angiography found its way into clinical routine for imaging vascular morphology. In conjunction with phase-contrast imaging, functional and morphological assessment of vascular pathology became possible. The flow dependence and associated artifacts inherent to these techniques have restricted the clinical use of these magnetic resonance angiography (MRA) techniques to the extra- and intracranial arterial, as well as the systemic and portal, venous systems. With the advent of high-performance gradient systems a new, promising MRA strategy has been developed: contrast-enhanced 3D MR angiography. It is based on the combination of rapid 3D imaging and the T1-shortening effect of intravenously infused paramagnetic contrast. This review provides a technical overview and critically discusses the clinical application for the different MRA techniques regarding morphological as well as functional assessment of the vascular system.     

Ultrafast contrast-enhanced 3D MR angiography of the aorta and renal arteries in apnea

Mixed medullary-follicular carcinomas (MMFC) of the thyroid are rare tumours showing the morphological and immunochemical properties of both parafollicular and follicular cell lineages. Their recognition is based on a classical WHO definition, although several other patterns have been described in recent years. We investigated 11 cases of MMFC by immunohistochemistry and in situ hybridization (ISH) to analyse the structural features, the immunophenotypic profile and the calcitonin (CT) and thyroglobulin (TG) gene expression of the neoplasm. Histologically, 10 cases had mixed parafollicular and follicular cell populations in the primary tumour and 1 only in the lymph node metastasis. All cases were immunoreactive for CT (in medullary areas) and TG (in follicular areas and also in the solid component of 8/11 cases). These findings were confirmed by ISH analysis. Combined ISH and immunostaining showed that most cases had separate CT and TG gene expression, although rare cells with concurrent CT and TG gene expression were identified in 2 tumours. We conclude that (a) MMFC display heterogeneous morphological patterns and are a special type of thyroid tumour undergoing divergent differentiation; (b) in MMFC, CT and TG genes are generally not simultaneously expressed by the same cell, although dual expression of CT and TG was present in rare neoplastic elements; and (c) the origin of MMFC, whether they are derived from the ultimo-branchial body or result from neoplastic transformation of different cell populations following common oncogenic stimuli, is unclear.     

Contrast-enhanced three-dimensional magnetic resonance angiography of the splanchnic vasculature before and after caloric stimulation. Original investigation

BACKGROUND: Onychomycosis, a fungal nail infection, has become one of the most important dermatophytoses. Unfortunately, a predictably successful diagnostic approach to onychomycosis does not yet exist. OBJECTIVE: The purpose of this study was to develop a deoxyribonucleic acid (DNA)-based diagnostic method to improve the sensitivity and specificity of the detection and differentiation of the pathogenic fungi of onychomycosis. METHODS: We attempted to detect fungi in the nail using polymerase chain reaction (PCR) primer systems that were designed in conserved sequences of the small ribosomal subunit 18S-rRNA genes shared by most fungi, and differentiated between species by restriction enzyme analysis of the amplified product. RESULTS: Fragments of the gene coding for 18S-rRNA were amplified successfully from medically important fungi species, but not from normal nails. Restriction fragment length polymorphism patterns using HaeIII endonuclease were sufficiently different to allow the recognition of individual species. CONCLUSIONS: The PCR-restriction enzyme analysis method appears to be a more sensitive detection and identification technique for onychomycosis than conventional methods, and has considerable diagnostic value.