Identification of self‐regulatory network motifs in reverse engineering gene regulatory networks using microarray gene expression data

Gene Regulatory Networks (GRNs) are reconstructed from the microarray gene expression data through diversified computational approaches. This process ensues in symmetric and diagonal interaction of gene pairs that cannot be modelled as direct activation, inhibition, and self‐regulatory interactions. The values of gene co‐expressions could help in identifying co‐regulations among them. The proposed approach aims at computing the differences in variances of co‐expressed genes rather than computing differences in values of mean expressions across experimental conditions. It adopts multivariate co‐variances using principal component analysis (PCA) to predict an asymmetric and non‐diagonal gene interaction matrix, to select only those gene pair interactions that exhibit the maximum variances in gene regulatory expressions. The asymmetric gene regulatory interactions help in identifying the controlling regulatory agents, thus lowering the false positive rate by minimizing the connections between previously unlinked network components. The experimental results on real as well as in silico datasets including time‐series RTX therapy, Arabidopsis thaliana, DREAM‐3, and DREAM‐8 datasets, in comparison with existing state‐of‐the‐art approaches demonstrated the enhanced performance of the proposed approach for predicting positive and negative feedback loops and self‐regulatory interactions. The generated GRNs hold the potential in determining the real nature of gene pair regulatory interactions.Inspec keywords: molecular biophysics, principal component analysis, genetics, biology computing, reverse engineeringOther keywords: controlling regulatory agents, interacting genes, unlinked network components, self‐regulatory interactions, gene pair regulatory interactions, self‐regulatory network motifs, reverse engineering gene regulatory networks, microarray gene expression data, diversified computational approaches, symmetric interaction, diagonal interaction, gene pairs, gene co‐expressions, co‐expressed genes, mean expressions, gene regulatory expressions, asymmetric gene regulatory interactions     

DIFFUSIONAL EFFECT OF PORES ON THE DENSIFICATION IN MICROGRAVITY LIQUID PHASE SINTERED FE-CU ALLOYS

OLiPSE-02 Fe-Cu samples, which were liquid phase sintered under 10 -5 torr in microgravity for 20, 30, 60, and 330 min for each composition, were analyzed in this article. The compositions of the samples are 80% Fe/Cu, 70% Fe/Cu, 60% Fe/Cu, and 50% Fe/Cu by volume. The experimental results of distortion and densification were presented. During the microgravity processing, liquid ejection occured for the long duration samples with compositions 70% Fe/Cu and 60% Fe/Cu. Measurements of the weights and dimensions of all the beads were made and their distributions were presented. One of the beads that are about the average weight and size from the 70% Fe/Cu long duration sample was chosen to be mounted, polished, etched, and analyzed under an optical microscope. The iron in the bead appeared as iron grains and its grain size was smaller than that in the mother sample with the same composition. Discussions of the bead and its iron grain formations are provided.     

A strategy for increasing use of autogenous hemodialysis access procedures: impact of preoperative noninvasive evaluation

PURPOSE: We studied the efficacy of preoperative noninvasive assessment of the upper extremity to identify arteries and veins suitable for hemodialysis access to increase our use of autogenous fistulas (AF). METHODS: From Sep. 1, 1994, to Apr. 1, 1997, 172 patients who required chronic hemodialysis underwent segmental upper extremity Doppler pressures and duplex ultrasound with mapping of arteries and veins. The following criteria were necessary for satisfactory arterial inflow: absence of a pressure gradient between arms, patent palmar arch, and arterial lumen diameter 2.0 mm or more. The criteria necessary for satisfactory venous outflow were venous luminal diameter greater than or equal to 2.5 mm for AF and greater than or equal to 4.0 mm for synthetic bridging grafts (BG) and continuity with distal superficial veins in the arm. Intraoperative and duplex ultrasound measurements were compared. Contemporary experience was compared with the 2-year period (1992 to 1994) before implementation of the protocol. RESULTS: During the period from Sep. 1, 1994, to Apr. 1, 1997, 108 patients (63%) had AF, 52 (30%) had prosthetic BG, and 12 (7%) had permanent catheters (PC) placed. Early failure was seen in 8.3% of AFs. Primary cumulative patency rates were 83% for AF and 74% for BG at 1 year (p < 0.05), with a mean clinical follow-up of 15.2 months. No postoperative infections were observed with AF, whereas six infections (12%) were observed with BG and two (17%) with PC insertion. During the period from June 1, 1992, to Aug. 31, 1994, 183 procedures were performed with a distribution of 14% AF, 62% BG, and 24% PC. In this earlier period the AF early failure rate was 36%, and the patency rates were 48%, 63%, and 48% for AF, BG, and PC, respectively (mean follow-up, 13.8 months). CONCLUSION: A protocol of noninvasive assessment increased use of AFs. The cumulative patency rate of AFs was improved, and early failure rates were reduced when compared with the preceding institutional experience. Routine noninvasive assessment is recommended to document adequacy of arterial inflow and delineate venous outflow to maximize opportunities for AF.     

Room-Temperature Photomagnetic Effect of Fe<Subscript>3</Subscript>Ga<Subscript>4</Subscript> Grown on GaAs Substrates

Ga–As–Fe composite films prepared by molecular beam epitaxy at 600°C on GaAs(100) substrates with the stacking sequence of [100-nm GaAs/50-nm Fe₃Ga_{2− x} As _x /100-nm GaAs] exhibit the distinct photo-enhanced magnetization at room temperature. Transmission electron microscopy reveals the formation of metamagnetic Fe₃Ga₄ grains on the sample surface. Illumination power dependence of the enhanced magnetization has been carefully compared with the antiferromagnetic-type magnetization–temperature (M–T) curve (Neel temperature of T _N = 340–390 K), from which we have discussed the existence of photon-mode photo-enhanced magnetization of some sort in addition with the enhancement due to the light-induced heating.     

Fabrication and characterization of novel zirconia filled glass fiber reinforced polyester hybrid composites

Novel hybrid glass fiber reinforced polyester composites (GFRPCs) filled with 1‐5 wt % microsized zirconia (ZrO₂) particles, were fabricated by hand lay‐up process followed by compression molding and evaluated their physical, mechanical and thermal behaviors. The consumption of styrene in cured GFRPCs was confirmed by Fourier transform infrared spectroscopy. The potential implementation of ZrO₂ particles lessened the void contents marginally and substantially enhanced the mechanical and thermal properties in the resultant hybrid composites. The GFRPCs filled with 4 wt % ZrO₂ illustrated noteworthy improvement in tensile strength (66.672 MPa) and flexural strength (67.890 MPa) while with 5 wt % ZrO₂ showed 63.93% rise in hardness, respectively, as compared to unfilled GFRPCs. Physical nature of polyester matrix for composites and an improved glass transition temperature (T_g) from 103 to 112 °C was perceived by differential scanning calorimetry thermograms. Thermogravimetric analysis revealed that the thermal stability of GFRPCs was remarkably augmented with the addition of ZrO₂. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43615.     

Microwave synthesis of zeolites from Egyptian kaolin: Evaluation of heavy metals removal

Zeolite A and analcime were prepared using microwave method and fully characterized. Both zeolites had high surface area and sharp peak. Both zeolite types were introduced for removal of 100 mg/L of 5 metal ions. The operating conditions were optimized. Adsorption followed pseudo-first-order kinetics and fits for Langmuir, Freundlich, Dubinin–Kaganer–Radushkevich, and Temkin models. Adsorption capacities were in the order Co > V > As > Pb > Ni. Zeolite A was more efficient in metal removal than analcime due to its higher surface area. Zeolite types can be used in efficient metals removal up to more than eight cycles.     

Silanization of ZnO nanofibers by tetraethoxysilane

Zinc oxide (ZnO) nanofibers are synthesized by electrospinning technique and then silanized to tailor its structural, optical, and electrical properties. The modification of ZnO nanofibers by chemical treatment of tetraethoxysilane (TEOS) is clearly evident from the appearance of relevant Fourier transform infrared peak at about 1000 cm^?1 corresponding to Zn? O? Si bond. The height of this peak increases linearly with increase in concentration of silane up to 400 μL, and afterward become plateau up to 500 μL. Diffuse reflectance spectroscopy measurement shows that band gap decreases from 3.35 eV for pure zinc oxide nanofibers to 3.11 eV with successive increase in concentration of TEOS from 100 to 500 μL. The electrical characteristics of modified ZnO nanofibers are analyzed by impedance spectroscopy. It is observed that impedance of ZnO nanofibers increases (resistance from 1.69 × 10⁸ to 2.618 × 10⁹ ohm and capacitance from 2.043 × 10^?12 to 7.618 × 10^?13 F) with increase of TEOS concentration. This study provides guidelines for tailoring the electrical properties of ZnO nanofibers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45378.     

Synthesis,Characterization, and Application Studies of Polyurethane Acrylate Thermoset Coatings: Effect of Hard Segment

The waterborne polyurethane acrylate coatings are smart option to reduce the environmental hazards. To evaluate the structure–property relationship, polyurethane acrylate coating dispersions were synthesized with aromatic and aliphatic hard segments. Furthermore, to evaluate the performance, dispersions were used to finish the cotton fabric. The dispersions were prepared by prepolymer method followed by emulsion polymerization in aqueous medium. The characterization of dispersions was performed by Fourier transform infrared, dynamic light scattering, atomic force microscopy, differential scanning calorimetry, and thermogravimetric analysis. In general, aliphatic hard segment has shown more appreciable results. But, thermal stability of aromatic polyurethane acrylate was more pronounced as inherent rigidity of aromatic diisocyanate dominates.