Showing papers by "Henan University of Technology published in 2011"

Single-crystalline MoO3 nanoplates: topochemical synthesis and enhanced ethanol-sensing performance

Abstract: Molybdate-based inorganic–organic hybrid disks with a highly ordered layered structure were synthesized via an acid–base reaction of white molybdic acid (MoO3·H2O) with n-octylamine (C8H17NH2) in ethanol at room temperature. The thermal treatment of the as-obtained molybdate-based inorganic–organic hybrid disks at 550 °C in air led to formation of orthorhombic α-MoO3 nanoplates. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal analysis (TG–DTA), Fourier-transform infrared (FT–IR) spectra, Raman spectra, and a laser-diffraction grain-size analyzer were used to characterize the starting materials, the intermediate hybrid precursors and the final α-MoO3 nanoplates. The XRD, FT–IR and TG–DTA results suggested that the molybdate-based inorganic–organic hybrid compound, with a possible composition of (C8H17NH3)2MoO4, was of a highly ordered lamellar structure with an interlayer distance of 2.306(1) nm, and the n-alkyl chains in the interlayer places took a double-layer arrangement with a tilt angle of 51° against the inorganic MoO6 octahedra layers. The SEM images indicated that the molybdate-based inorganic–organic hybrids took on a well-dispersed disk-like morphology, which differed distinctly from the severely aggregated morphology of their starting MoO3·H2O powders. During the calcining process, the disk-like morphology of the hybrid compounds was well inherited into the orthorhombic α-MoO3 nanocrystals, showing a definite plate-like shape. The α-MoO3 nanoplates obtained were of a single-crystalline structure, with a side-length of 1–2 μm and a thickness of several nanometres, along a thickness direction of [010]. The above α-MoO3 nanoplates were of a loose aggregating texture and high dispersibility. The chemical sensors derived from the as-obtained α-MoO3 nanoplates showed an enhanced and selective gas-sensing performance towards ethanol vapors. The α-MoO3 nanoplate sensors reached a high sensitivity of 44–58 for an 800 ppm ethanol vapor operating at 260–400 °C, and their response times were less than 15 s.

High sensitive simultaneous determination of hydroquinone and catechol based on graphene/BMIMPF6 nanocomposite modified electrode

Abstract: A novel nanocomposite, comprising of graphene sheet (GS) and ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF 6 ), was developed on the glassy carbon electrode (GCE) for the simultaneous determination of hydroquinone and catechol in 0.10 M acetate buffer solution (pH 5.0). At the GS/BMIMPF 6 /GCE, both hydroquinone and catechol can cause a pair of quasi-reversible and well-defined redox peaks. In comparison with bare GCE and GS modified electrode, GS/BMIMPF 6 /GCE showed larger peak currents, which was related to the higher specific surface area of graphene and high ionic conductivity of BMIMPF 6 . Under the optimized condition, the cathodic peak current were linear over ranges from 5.0 × 10 −7 M to 5.0 × 10 −5 M for hydroquinone and from 5.0 × 10 −7 M to 5.0 × 10 −5 M for catechol, with the detection limits of 1.0 × 10 −8 M and 2.0 × 10 −8 M, respectively. The proposed method was successfully applied to the simultaneous determination of hydroquinone and catechol in artificial sample, and the results are satisfactory.

Chromatin-modifying drugs induce miRNA-153 expression to suppress Irs-2 in glioblastoma cell lines.

Abstract: MicroRNAs (miRNAs) are noncoding RNAs that regulate gene expression by inhibiting translation or by promoting mRNA degradation. Previously, we established that microRNA-153 (miR-153) induces apoptosis by downregulating B-cell lymphoma 2 (Bcl-2) and myeloid cell leukemia sequence 1 (Mcl-1) protein expression levels in glioblastoma cell line DBTRG-05MG. In our study, we show that ectopic expression of miR-153 also inhibits the protein kinase B (PKB/Akt) pathway via reducing the protein level of insulin receptor substrate-2 (Irs-2). Moreover, simultaneous treatment with the chromatin-modifying drugs 4-phenylbutyric acid and 5-aza-2′-deoxycytidine induces miR-153 expression to suppress Irs-2, Bcl-2 and Mcl-1 expressions, thus downregulating the survival but upregulating the apoptotic pathways, implying that tumor suppressor miR-153 is a dual life and death regulator.

Aqueous Enzymatic Extraction of Oil and Protein Hydrolysates from Roasted Peanut Seeds

Abstract: To evaluate the effects of the roasting process on the extraction yield and oil quality, peanut seeds were roasted at different temperatures (130–220 °C) for 20 min prior to the aqueous extraction of both oil and protein hydrolysates with Alcalase 2.4 L. Roasting temperatures did not significantly affect the yields of free oil, whereas the temperature of 220 °C led to a reduced recovery of protein hydrolysates. The color and acid values of peanut oils did not change significantly with roasting temperatures. The enzyme-extracted oil with roasting at 190 °C had a relatively low peroxide value, a strong oxidative stability, and the best flavor score. Using the same seed-roasting temperature (190 °C), quality attributes such as color, acid and peroxide values, phosphorus content and oxidative stability of the enzyme-extracted oil were better than those of the oil obtained by an expeller. After the peanut seeds were roasted at 190 °C for 20 min, with a seeds-to-water ratio of 1:5, an enzyme concentration of 2%, and an incubation time of 3 h, the yields of free oil and protein hydrolysates were 78.6 and 80.1%, respectively. After demulsification of the residual emulsion by a freezing and thawing method, the total free oil yield increased to 86–90%.

Accurate Numerical Methods for Computing 2D and 3D Robot Workspace

Abstract: Exact computation of the shape and size of robot manipulator workspace is very important for its analysis and optimum design First, the drawbacks of the previous methods based on Monte Carlo are pointed out in the paper, and then improved strategies are presented systematically In order to obtain more accurate boundary points of two-dimensional (2D) robot workspace, the Beta distribution is adopted to generate random variables of robot joints And then, the area of workspace is acquired by computing the area of the polygon what is a closed path by connecting the boundary points together For comparing the errors of workspaces which are generated by the previous and the improved method from shape and size, one planar robot manipulator is taken as example A spatial robot manipulator is used to illustrate that the methods can be used not only on planar robot manipulator, but also on the spatial The optimal parameters are proposed in the paper to computer the shape and size of 2D and 3D workspace Finally, we provided the computation time and discussed the generation of 3D workspace which is based on 3D reconstruction from the boundary points

Synthesis of high fatty acid starch esters with 1-butyl-3-methylimidazolium chloride as a reaction medium

Abstract: In this work, high fatty acid esters of corn starch were synthesized by reacting the starch with fatty acid methyl ester using 1-butyl-3-methylimidazolium chloride (BMIMCl) ionic liquid (IL) as reaction media. The effect of reaction variables such as the catalyst amount, molar ratio of fatty acid methyl ester/anhydroglucose unit (AGU) in starch, pyridine/AGU molar ratio, reaction temperature, as well as reaction time on the degree of substitution (DS) of starch esters was investigated. The experimental results showed that the DS value of the obtained starch esters could be varied depending on the process conditions. In the optimum reaction condition, the achieved maximum DS of starch laurate and starch stearate was 0.37 and 0.28, respectively, at a reaction temperature of 110°C for starch laurate and 120°C for starch stearate for a reaction duration of 2 h. Furthermore, the starch esters were characterized by FTIR, SEM, and X-ray diffractometry (XRD) techniques, respectively. Results from FT-IR spectroscopy suggested that the hydroxyl groups in the starch molecules were converted into ester groups. SEM and XRD studies showed that the morphology and crystallinity of starch esters were disrupted largely in the IL medium under the reaction conditions.

Genetic structure composed of additive QTL, epistatic QTL pairs and collective unmapped minor QTL conferring oil content and fatty acid components of soybeans

Abstract: The relative importance of various types of quantitative trait locus (QTL) conferring oil content and its fatty acid components in soybean seeds was assessed through testing a recombinant inbred line (RIL) population (derived from KF1 × NN1138-2) in randomized blocks experiments in 2004–2006. The contents of oil and oleic, linoleic, linolenic, palmitic and stearic acids were determined with automatic Soxhlet extraction system and gas chromatography, respectively. Based on the established genetic linkage map with 834 markers, QTLNetwork2.0 was used to detect QTL under the genetic model composed of additive, additive × additive (epistasis), additive × year and epistasis × year effects. The contributions to the phenotypic variances of additive QTL and epistatic QTL pairs were 15.7% (3 QTL) and 10.8% (2 pairs) for oil content, 10.4% (3 QTL) and 10.3% (3 pairs) for oleic acid, 11.6% (3 QTL) and 8.5% (2 pairs) for linoleic acid, 28.5% (7 QTL) and 7.6% (3 pairs) for linolenic acid, 27.0% (6 QTL) and 16.6% (7 pairs) for palmitic acid and 29.7% (5 QTL) and 4.3% (1 pair) for stearic acid, respectively. Those of additive QTL by year interaction were small and no epistatic QTL pair by year interaction was found. Among the 27 additive QTL and 36 epistatic QTL (18 pairs), three are duplicated between the two QTL types. A large difference was found between the genotypic variance among RILs and the total variance of mapped QTL, which accounted for 52.9–74.8% of the genotypic variation, much larger than those of additive QTL and epistatic QTL pairs. This part of variance was recognized as that due to a collection of unmapped minor QTL, like polygenes in biometrical genetics, and was designated as collective unmapped minor QTL. The results challenge the breeders for how to pyramid different types of QTL. In addition, the present study supports the mapping strategy of a full model scanning followed by verification with other procedures corresponding to the first results.

Synthesis of chromium carbide (Cr3C2) nanopowders by the carbonization of the precursor

Abstract: The solution-derived precursor method was used to synthesize chromium carbide (Cr 3 C 2 ) nanopowders, ammonium dichromate ((NH 4 ) 2 Cr 2 O 7 ) and nanometer carbon black were used as raw materials. The products were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The results show that the single phase Cr 3 C 2 can be synthesized under the conditions of 21 wt.% C, 1100 °C and 30 min, and the average crystallite size is 27.2 nm. The powders show good dispersion and are mainly composed of spherical or near- spherical particles with a mean diameter of ~ 30 nm. The surface of the specimen mainly consists of Cr, C and O three species elements. The XPS spectrum of Cr2p consists of two peaks with the binding energies of 577.5 eV and 575.3 eV, which are assigned to the Cr2p 3/2 species of Cr 2 O 3 and Cr 3 C 2 − x (0 ≤ x ≤ 0.5), respectively. The XPS spectrum of O1s energy region for chromium carbide contains three peaks (Oa, Oh and Od), which are considered to be due to O − , OH − and Cr 2 O 3 , respectively.

Traffic accident automatic detection and remote alarm device

Abstract: An automatic alarm device for traffic accidents is introduced in this paper. It can automatically detect a traffic accident, search for the spot and then send the basic information to first aid center within two seconds covering geographical coordinates, the time and circumstances in which a traffic accident takes place. By means of satellite navigation system, first aid rescuers can accurately locate the place with maximum error controlled by 10 meters, so that they can save the injured people as soon as possible.

Overexpression of a Wheat CCaMK Gene Reduces ABA Sensitivity of Arabidopsis thaliana During Seed Germination and Seedling Growth

Abstract: Abscisic acid (ABA) plays pivotal roles in plant biotic and abiotic stress responses, where calcium ions are important second messengers. Calcium/calmodulin-dependent protein kinase (CCaMK) is essential for nodulation in legumes, but whether it will perceive calcium signals from abiotic stresses is not clear, especially in non-legume plants. Here we report the isolation and characterization of the D-genome copy of wheat CCaMK gene TaCCaMK. TaCCaMK was predominantly expressed in root tissues of wheat seedlings, and its proteins were located both on the cytoplasm membrane and in the nucleus as shown in the onion epidermis cells. Quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) assay showed that the expression of TaCCaMK was downregulated by ABA, as well as NaCl and PEG treatments in wheat seedling roots. A DNA fragment of 1,119 bp upstream of the start codon of the TaCCaMK gene (pTaCCaMK) was isolated by thermal asymmetric interlaced PCR (TAIL-PCR), on which six ABA-responsive cis-elements were predicted. pTaCCaMK can drive GUS reporter gene expression in the root and stem stalk of the transgenic Arabidopsis plants which can be repressed by ABA treatments, consistent with the observation in the qRT-PCR assay in wheat. Overexpressing TaCCaMK in Arabidopsis plants reduced their sensitivity to ABA treatment during seed germination and root elongation. Under high-salt conditions, the transgenic plants also conferred enhanced seed germination rate and became hypersensitive with increased chlorosis. Therefore, our data suggest that TaCCaMK is a negative regulator for ABA signaling which may participate in abiotic stress responses in wheat.

Special fiber elements for thermal analysis of fiber‐reinforced composites

Abstract: Purpose – The purpose of this paper is to present a new special element model for thermal analysis of composites.Design/methodology/approach – A hybrid finite element formulation taking the fundamental solution as kernel function is presented in this work for analyzing the thermal behavior and predicting the effective thermal conductivity of fiber‐reinforced composites. A representative volume cell containing single or multiple fibers (or inclusions) is considered to investigate the overall temperature distribution affected by the inclusions and the interactions among them, and to evaluate the effective thermal conductivity of the composites using the presented algorithm with special‐purpose inclusion elements. Numerical examples are presented to demonstrate the accuracy and applicability of the proposed method in analyzing fiber‐reinforced composites.Findings – The independent intra‐element field and frame field, as well as the newly‐developed hybrid functional, make the algorithm versatile in terms of e...

Simultaneous voltammetric detection of dopamine and uric acid in the presence of high concentration of ascorbic acid using multi-walled carbon nanotubes with methylene blue composite film-modified electrode

Abstract: An electrochemically functional nanocomposite through the adsorption of methylene blue onto the multi-walled nanotubes (MB-MWNTs) was prepared, and a sensitive voltammetric sensor was fabricated. The modified electrode showed excellent electrocatalytic activity toward dopamine (DA) and uric acid (UA) in 0.1 M phosphate solution medium (pH 3.0). Compared to the bare electrode, the MB-MWNTs film-modified electrode not only remarkably enhanced the anodic peak currents of DA and UA, i.e., shifted the anodic peak potential of DA negatively, but also avoided the overlapping of the anodic peaks of DA and UA. The interference of ascorbic acid (AA) was eliminated. Under the optimized conditions, the peak separation between AA and DA and between DA and UA was 219 and 174 mV, respectively. In the presence of 1.0 mM AA and 10.0 μM UA, the anodic peak current was linear to the concentration of DA in the range of 0.4–10.0 μM with a detection limit of 0.2 μM DA. The anodic peak current of UA was linear to the concentration in the range of 2.0–20.0 and 20.0–200.0 μM with a lowest detection limit of 1.0 μM in the presence of 1.0 mM AA and 1.0 μM DA.

Distribution and molecular characterization of β-glucans from hull-less barley bran, shorts and flour.

Abstract: Six hull-less barley cultivars widely grown in China were roller-milled to produce bran, shorts and flour fractions. The distribution and molecular characteristics of β-glucans from the three roller-milled fractions were investigated. The β-glucan contents in the six hull-less barley cultivars varied from 4.96% to 7.62%. For all the six cultivars, the shorts fraction contained the highest concentration of β-glucan (8.12–13.01%), followed by bran (6.15–7.58%) and flour (2.48–2.95%). Crude β-glucans were prepared from the three roller-milled fractions using aqueous sodium carbonate (pH 10). These preparations contained 45.38–71.41% β-glucan, 10.81–17.26% arabinoxylan, 2.6–9.6% protein, 2.7–9.0% starch, and 5.23–9.68% ash. Purification using α-amylase and β-xylanase in combination with pH adjustment and dialysis produced high purity β-glucan preparations (91–95%). The molecular weight (Mw) of β-glucan preparations from roller-milled fractions ranged from 117,600 to 852,400 g/mol. β-Glucan from flour had higher Mw than those from shorts and bran within the same cultivar, and β-glucan preparations from bran had the lowest Mw.

Enzymatic Epoxidation of Corn Oil by Perstearic Acid

Abstract: Epoxidized vegetable oils can be used as renewable biodegradable and non-toxic lubricants, polymer stabilizers, and as intermediates. In this study, as a renewable resource, corn oil rich in oleic and linoleic acids, which was epoxidized using hydrogen peroxide as an oxygen donor and stearic acid as an active oxygen carrier in the presence of Novozym 435. The process was optimized for the enzymatic epoxidation of corn oil with an epoxy oxygen group content of 5.8 ± 0.2% and a percentage relative conversion to oxirane of 85.3 ± 2.9% under the following conditions: 35 °C, 28% stearic acid load (relative to the weight of corn oil), 2.7:1 mol ratio of H2O2/C=C-bonds, and 10 h. The influence on the enzymatic epoxidation decreased in the order of stearic acid load > reaction temperature ≈ mole ratio of H2O2/C=C-bonds >reaction time.

Effects of protein content, glutenin-to-gliadin ratio, amylose content, and starch damage on textural properties of Chinese fresh white noodles

Abstract: The independent effects of flour protein and starch on textural properties of Chinese fresh white noodles were investigated through reconstitution of fractionated flour components. Noodle hardness decreased with decreased protein content, whereas it unexpectedly increased as protein content decreased to a very low level (7.0%). Noodle cohesiveness, tensile strength, and breaking length increased with increased protein content. Higher glutenin-to-gliadin ratio resulted in harder and stronger noodles at constant protein content. Increased starch amylose content resulted in increased flour peak viscosity. When water absorption remained the same during noodle making, hardness and cohesiveness of cooked noodles also increased with increased starch amylose content, while springiness did not vary significantly. Increased starch damage of ≈5.5–10.4% effectively improved noodle hardness; however, starch damage >10.4% decreased it. Increased starch damage also enhanced noodle springiness while it decreased...

Diels–Alder reaction in water for the straightforward preparation of thermoresponsive hydrogels

Abstract: Because the properties and applications of hydrogels are determined by the formation principle and conditions of the hydrogels, novel methods for preparing hydrogels have increasingly triggered scientists' interest. Here the Diels–Alder reaction was applied to the preparation of hydrogels. For the resultant polymeric diene and dienophile, the Diels–Alder reaction could be performed in water. The gelation time was found to be closely related to the temperature. The gelation time decreased with the temperature increasing. Moreover, the hydrogels were stable in water, and the retro-Diels–Alder reaction could be performed in N,N-dimethylformamide easily. A study of the swelling ratio indicated that the hydrogels were responsive to the temperature. The hydrogel formation method described here provides several advantages, such as mild reaction conditions, no initiator or catalyst, a tunable gelation rate, and thermal reversibility, and it has great potential for the preparation of biomaterials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

A New Three-Dimensional Imaging Algorithm for Airborne Forward-Looking SAR

Abstract: In this letter, a new 3-D imaging algorithm is proposed for forward-looking synthetic aperture radar based on the imaging geometry and the characteristic of the echo signal. The key point of the proposed algorithm is the introduction of the nonlinear frequency modulation scaling in along-track processing to obtain accurate focusing. As the method needs only Fourier transform and multiplication operations, it is computationally efficient. Simulations with point scatterers are used to validate the method.

Anatomical localization and stereoisomeric composition of Tribolium castaneum aggregation pheromones

Abstract: We report that the abdominal epidermis and associated tissues are the predominant sources of male-produced pheromones in the red flour beetle, Tribolium castaneum and, for the first time, describe the stereoisomeric composition of the natural blend of isomers of the aggregation pheromone 4,8-dimethyldecanal (DMD) in this important pest species. Quantitative analyses via gas chromatography–mass spectrometry showed that the average amount of DMD released daily by single feeding males of T. castaneum was 878 ± 72 ng (SE). Analysis of different body parts identified the abdominal epidermis as the major source of aggregation pheromone; the thorax was a minor source, while no DMD was detectable in the head. No internal organs or obvious male-specific glands were associated with pheromone deposition. Complete separation of all four stereoisomers of DMD was achieved following oxidation to the corresponding acid, derivatization with (1R, 2R)- and (1S, 2S)-2-(anthracene-2,3-dicarboximido)cyclohexanol to diastereomeric esters, and their separation on reversed-phase high-performance liquid chromatography at −54°C. Analysis of the hexane eluate from Porapak-Q-collected volatiles from feeding males revealed the presence of all four isomers (4R,8R)/(4R,8S)/(4S,8R)/(4S,8S) at a ratio of approximately 4:4:1:1. A walking orientation bioassay in a wind tunnel with various blends of the four synthetic isomers further indicated that the attractive potency of the reconstituted natural blend of 4:4:1:1 was equivalent to that of the natural pheromone and greater than that of the 1:1 blend of (4R,8R)/(4R,8S) used in commercial lures.