Showing papers by "Henan University of Technology published in 2014"

Enzymatic Production of Biodiesel from Soybean Oil by Using Immobilized Lipase on Fe3O4/Poly(styrene-methacrylic acid) Magnetic Microsphere as a Biocatalyst

Abstract: A magnetic composite poly(styrene-methacrylic acid) microsphere, was prepared using oleic acid-coated magnetic nanoparticles as seeds by microemulsion copolymerization of styrene (St) and methacrylic acid (MAA). The lipase from Candida rugosa was then covalently bound to the magnetic polymer-coated microspheres by using 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDAC) as an activation reagent. The immobilization of lipase could enhance the thermal and pH stability of lipase activity when compared to free lipase. The immobilized lipase microspheres were characterized by lipase activity assays, Fourier transform infrared spectroscopy, powder X-ray diffraction, transmission electron microscopy, and vibrating-sample magnetometer techniques. The bound lipase showed high activities to soybean oil transesterification with methanol to produce biodiesel. It was found that the oil conversion of 86% was attained at a reaction temperature of 35 °C for 24 h. The immobilized lipase is stable with re...

Comments on “Finite-Time $H_{\infty }$ Fuzzy Control of Nonlinear Jump Systems With Time Delays Via Dynamic Observer-Based State Feedback”

Abstract: This paper investigates a defect appearing in “Finite-time H∞ fuzzy control of nonlinear jump systems with time delays via dynamic observer-based state feedback,” which the observer-based finite-time H∞ controller via dynamic observer-based state feedback could not ensuring stochastic finite-time boundedness, and satisfying a prescribed level of H∞ disturbance attenuation for the resulting closed-loop error fuzzy Markov jump systems. The corrected results are presented, and the improved optimal algorithms and new simulation results are also provided in this paper.

Biology of ageing and role of dietary antioxidants.

Abstract: Interest in relationship between diet and ageing is growing Research has shown that dietary calorie restriction and some antioxidants extend lifespan in various ageing models On the one hand, oxygen is essential to aerobic organisms because it is a final electron acceptor in mitochondria On the other hand, oxygen is harmful because it can continuously generate reactive oxygen species (ROS), which are believed to be the factors causing ageing of an organism To remove these ROS in cells, aerobic organisms possess an antioxidant defense system which consists of a series of enzymes, namely, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) In addition, dietary antioxidants including ascorbic acid, vitamin A, vitamin C, α-tocopherol, and plant flavonoids are also able to scavenge ROS in cells and therefore theoretically can extend the lifespan of organisms In this connection, various antioxidants including tea catechins, theaflavins, apple polyphenols, black rice anthocyanins, and blueberry polyphenols have been shown to be capable of extending the lifespan of fruit flies The purpose of this review is to brief the literature on modern biological theories of ageing and role of dietary antioxidants in ageing as well as underlying mechanisms by which antioxidants can prolong the lifespan with focus on fruit flies as an model

Kinesin Family Deregulation Coordinated by Bromodomain Protein ANCCA and Histone Methyltransferase MLL for Breast Cancer Cell Growth, Survival, and Tamoxifen Resistance

Abstract: Kinesins are a superfamily of motor proteins and often deregulated in different cancers. However, the mechanism of their deregulation has been poorly understood. Through examining kinesin gene family expression in estrogen receptor (ER)-positive breast cancer cells, we found that estrogen stimulation of cancer cell proliferation involves a concerted regulation of specific kinesins. Estrogen strongly induces expression of 19 kinesin genes such as Kif4A/4B, Kif5A/5B, Kif10, Kif11, Kif15, Kif18A/18B, Kif20A/20B, Kif21, Kif23, Kif24, Kif25, and KifC1, whereas suppresses the expression of seven others, including Kif1A, Kif1C, Kif7, and KifC3. Interestingly, the bromodomain protein ANCCA/ATAD2, previously shown to be an estrogen-induced chromatin regulator, plays a crucial role in the up- and downregulation of kinesins by estrogen. Its overexpression drives estrogen-independent upregulation of specific kinesins. Mechanistically, ANCCA (AAA nuclear coregulator cancer associated) mediates E2-dependent recruitment of E2F and MLL1 histone methyltransferase at kinesin gene promoters for gene activation–associated H3K4me3 methylation. Importantly, elevated levels of Kif4A, Kif15, Kif20A, and Kif23 correlate with that of ANCCA in the tumors and with poor relapse-free survival of patients with ER-positive breast cancer. Their knockdown strongly impeded proliferation and induced apoptosis of both tamoxifen-sensitive and resistant cancer cells. Together, the study reveals ANCCA as a key mediator of kinesin family deregulation in breast cancer and the crucial role of multiple kinesins in growth and survival of the tumor cells. Implications: These findings support the development of novel inhibitors of cancer-associated kinesins and their regulator ANCCA for effective treatment of cancers including tamoxifen-resistant breast cancers. Mol Cancer Res; 12(4); 539–49. ©2014 AACR.

A study into the extracted ion number for NASICON structured Na3V2(PO4)3 in sodium-ion batteries

Abstract: Excellent C-rate and cycling performance with a high specific capacity of 117.6 mA h g−1 have been achieved on NASICON-structure Na3V2(PO4)3 sodium-ion batteries. Two different Na sites, namely Na(1) and Na(2), are reported in the open three-dimensional framework, of which the ions at the Na(2) sites should be mainly responsible for the electrochemical properties. It is vitally important and interesting to find that there are two kinds of possible ion occupation of Na ions in Na3V2(PO4)3 and the investigation of ion-extraction number is firstly explored by discussing ion occupations with the help of first-principles calculations. The ion occupation of 0.75 for all Na sites is suitable for the configuration of [Na3V2(PO4)3]2, and the two-step extraction process accompanied by structure reorganization can account for the theoretical capacity of Na3V2(PO4)3.

Investigation of the sodium ion pathway and cathode behavior in Na₃V₂(PO₄)₂F₃ combined via a first principles calculation.

Abstract: The electrochemical properties of Na3V2(PO4)2F3 cathode utilized in the sodium ion battery are investigated, and the ion migration mechanisms are proposed as combined via the first principles calculations. Two different Na sites, namely, the Na(1) and Na(2) sites, could cause two sodium ions of Na3V2(PO4)2F3 to be extracted or inserted by a two-step electrochemical process accompanied by structural reorganization that could be responsible for the redox reaction of V(3+/4+). Because the calculated average voltage (V(avg)) of the second charging plateau is 4.04 V for the optimized system but 4.38 V for the unoptimized one, the reorganization of the cathode system can make a stable configuration and lower the extraction energy. Three designed pathways for sodium ions along the x, y, z directions in Na3V2(PO4)2F3, known as a 3D ions transport tunnel, have activation energies (Ea) of 0.449, 0.2, and 0.323 eV, respectively, by using DFT calculations, demonstrating the different feasibilities of the migration directions.

Silver-catalyzed radical tandem cyclization: an approach to direct synthesis of 3-acyl-4-arylquinolin-2(1H)-ones.

Abstract: A silver-catalyzed efficient and practical synthesis of 3-acyl-4-arylquinolin-2(1H)-ones or 3-acyl-4-aryldihydroquinolin-2(1H)-ones through intermolecular radical addition/cyclization in aqueous solution is reported. This method provides a novel, highly efficient, and straightforward route to substituted quinolin-2-ones or 3,4-dihydroquinolin-2-ones in one step. A possible mechanism for the formation of quinolin-2-ones is proposed.

Determination of organophosphate pesticides using an acetylcholinesterase-based biosensor based on a boron-doped diamond electrode modified with gold nanoparticles and carbon spheres

Abstract: We report on a biosensor for organophosphate pesticides (OPs) by exploiting their inhibitory effect on the activity of acetylcholinesterase (AChE). A boron-doped diamond (BDD) electrode was modified with a nanocomposite prepared from carbon spheres (CSs; with an average diameter of 500 nm) that were synthesized from resorcinol and formaldehyde, and then were coated with gold nanoparticles (AuNPs) by chemically growing them of the CSs. Compared to a bare BDD electrode, the electron transfer resistance is lower on this new electrode. Compared to an electrode without Au-NPs, the peak potential is negatively shifted by 42 mV, and the peak current is increased by 55 %. This is ascribed to the larger surface in the AuNP-CS nanocomposite which improves the adsorption of AChE, enhances its activity, and facilitates electrocatalysis. Under optimum conditions, the inhibitory effect of chlorpyrifos is linearly related to the negative log of its concentration in the 10−11 to 10−7 M range, with a detection limit of 1.3 × 10−13 M. For methyl parathion, the inhibition effect is linear in the 10−12 to 10−6 M range, and the detection limit is 4.9 × 10−13 M. The biosensor exhibits good precision and acceptable operational and temporal stability.

A novel damage-tolerant superhydrophobic and superoleophilic material

Abstract: A damage-tolerant superhydrophobic and superoleophilic bulk material is fabricated by a facile method. The novel bulk material demonstrates excellent resistance for oil fouling and can be used for water–oil separation. Different wettabilities have been realized on the material surface under UV irradiation, and the superhydrophobicity can be easily regenerated.

Peroxides as “Switches” of Dialkyl H-Phosphonate: Two Mild and Metal-Free Methods for Preparation of 2-Acylbenzothiazoles and Dialkyl Benzothiazol-2-ylphosphonates

Abstract: Two mild and metal-free methods for the preparation of two kinds of important benzothiazole derivatives, 2-acylbenzothiazoles and dialkyl benzothiazol-2-ylphosphonates, respectively, were developed. The dialkyl H-phosphonate (RO)2P(O)H exists in equilibrium with its tautomer dialkyl phosphite (RO)2POH. TBHP triggered α-carbon-centered phosphite radical formation, whereas DTBP triggered phosphorus-centered phosphonate radical formation. The two types of radicals led respectively to two different reaction processes, the direct C2-acylation of benzothiazoles and C2-phosphonation of benzothiazoles.

Effects of ultrasonic cavitation intensity on the efficient liquid-exfoliation of MoS2 nanosheets

Abstract: Liquid exfoliation has been widely used to yield two dimensional layered materials in laboratory because of its simplicity and ease for mass production characteristics. In this study, the dispersions and morphology of exfoliated MoS2 in N-methyl-2-pyrrolidone (NMP) solvent at different ultrasonic powers are investigated. An optimal power to exfoliate MoS2 nanoflakes in NMP for high yield and small lateral size with narrow size distribution is obtained. Our results showed that the concentration of dispersions did not monotonously increase with growing ultrasonic power, but rather initially increased with input power, and then decreased after 320 W due to the cavitation shielding effect. The flake size decreased with ultrasonic power from 100 W to 250 W and then slightly increased; after 320 W, the average lateral size of flakes dramatically increased and a wide size distribution with relatively large scale nano-flakes was detected. The mechanism of ultrasonic cavitation effect on the concentration and morphology has been analyzed.

Comparison of Graphene-Based Transverse Magnetic and Electric Surface Plasmon Modes

Abstract: Dispersion properties and field distributions of graphene supported transverse magnetic (TM) and transverse electric (TE) surface plasmon (SP) modes in air-graphene-SiO2-Si structures have been investigated. The results show that graphene-based TM (TE) SPs are bound (lossy) modes, which decay into the air in the range of tens of micrometers (several thousand micrometers). In addition, when the thickness of the SiO2 layer is in the range of 200-300 nm, the influence of the Si substrate on the dispersion property is significant (negligible) for the TM (TE) modes. Furthermore, the effective indexes of the graphene TM (TE) modes increase with the increase (decrease) of the frequency. Compared with the traditional metal-based structures, graphene-based TM mode exhibits a better confinement but with a larger loss. The presented results are useful for the design of compact graphene-based optoelectronic devices.

Hybrid sampling strategy-based multiobjective evolutionary algorithm for process planning and scheduling problem

Abstract: Process planning and scheduling (PPS) is an important and practical topic but very intractable problem in manufacturing systems. Many research studies used multiobjective evolutionary algorithm (MOEA) to solve such problems; however, they cannot achieve satisfactory results in both quality and computational speed. This paper proposes a hybrid sampling strategy-based multiobjective evolutionary algorithm (HSS-MOEA) to deal with the PPS problem. HSS-MOEA tactfully combines the advantages of vector evaluated genetic algorithm (VEGA) and a sampling strategy according to a new Pareto dominating and dominated relationship-based fitness function (PDDR-FF). The sampling strategy of VEGA prefers the edge region of the Pareto front and PDDR-FF-based sampling strategy has the tendency converging toward the central area of the Pareto front. These two mechanisms preserve both the convergence rate and the distribution performance. The numerical comparisons state that the HSS-MOEA is better than a generalized Pareto-based scale-independent fitness function based genetic algorithm combing with VEGA in efficacy (convergence and distribution) performance, while the efficiency is closely equivalent. Moreover, the efficacy performance of HSS-MOEA is also better than NSGA-II and SPEA2, and the efficiency is obviously better than their performance.

RAID: a comprehensive resource for human RNA-associated (RNA–RNA/RNA–protein) interaction

Abstract: Transcriptomic analyses have revealed an unexpected complexity in the eukaryote transcriptome, which includes not only protein-coding transcripts but also an expanding catalog of noncoding RNAs (ncRNAs). Diverse coding and noncoding RNAs (ncRNAs) perform functions through interaction with each other in various cellular processes. In this project, we have developed RAID (http://www.rna-society.org/raid), an RNA-associated (RNA-RNA/RNA-protein) interaction database. RAID intends to provide the scientific community with all-in-one resources for efficient browsing and extraction of the RNA-associated interactions in human. This version of RAID contains more than 6100 RNA-associated interactions obtained by manually reviewing more than 2100 published papers, including 4493 RNA-RNA interactions and 1619 RNA-protein interactions. Each entry contains detailed information on an RNA-associated interaction, including RAID ID, RNA/protein symbol, RNA/protein categories, validated method, expressing tissue, literature references (Pubmed IDs), and detailed functional description. Users can query, browse, analyze, and manipulate RNA-associated (RNA-RNA/RNA-protein) interaction. RAID provides a comprehensive resource of human RNA-associated (RNA-RNA/RNA-protein) interaction network. Furthermore, this resource will help in uncovering the generic organizing principles of cellular function network.

Structure and Physical Properties of Organogels Developed by Sitosterol and Lecithin with Sunflower Oil

Abstract: High linoleic acid sunflower oil (HLSO) with various sitosterol (Sit) to lecithin (Lec) mass ratios (i.e., 0:100–100:0) were used to develop organogels at two storage temperatures (T s: 5 and 25 °C). The results showed that, at 25 °C, the hardness value of organogels obtained from HLSO with both Sit and Lec was higher than that of organogels developed from HLSO with only Sit or Lec. Microscopy revealed that the shapes of the crystals in the organogels varied significantly with the composition of the structurant and the T s. At both T s used, the Sit:Lec (80:20) system had a lower degree of supersaturation compared with the (100:0) system. X-ray diffraction (XRD) revealed that Sit:Lec mass ratio of 70:30, 80:20 and 100:0 had similar short spacings, and the presence of Lec might be adverse to the formation of Sit crystal in oil. Small-angel X-ray scattering (SAXS) showed that the layer thickness of Sit/Lec/HLSO organogel was larger than that of Sit/HLSO organogel. It was found that the presence of Lec induced the change of self-assembly structure of Sit in HLSO and caused the changes of physical properties of organogels obtained.

A Wideband Merged CMOS Active Mixer Exploiting Noise Cancellation and Linearity Enhancement

Abstract: A wideband CMOS active mixer is proposed with improved noise and linearity, merging a resistive feedback noise-canceling low-noise amplifier as its transconductor. The noise-canceling characteristic enables the transconductor with low noise over a wide frequency range. An auxiliary pMOS transistor is employed to cancel the third-order nonlinear currents of a composite transistor in the transconductor, and impair the second-order nonlinear currents of that. To enhance input equivalent transconductance, a bulk cross-coupled feedback is applied to the transistor in the transconductor with large power consumption. Together with a current bleeding technique, comparable gain, noise, and improved linearity are achieved, but by reduced bias currents of the mixer. Fabricated in a 0.13- μm triple-well RF CMOS process, the proposed mixer demonstrates a voltage gain of 16.3-14.4 dB, average noise figure of 4.2 dB, and input-referred third-order intercept point of 7.3-2.5 dBm, operating between 500 MHz-5.8 GHz. It consumes 17 mA from a 1.5-V supply and occupies an area of 1.1×1.1 mm 2 .

Ultra-sensitive electrochemical DNA biosensor based on signal amplification using gold nanoparticles modified with molybdenum disulfide, graphene and horseradish peroxidase

Abstract: We have developed an ultra-sensitive electrochemical DNA biosensor by assembling probe ssDNA on a glassy carbon electrode modified with a composite made from molybdenum disulfide, graphene, chitosan and gold nanoparticles. A thiol-tagged DNA strand coupled to horseradish peroxidase conjugated to AuNP served as a tracer. The nanocomposite on the surface acts as relatively good electrical conductor for accelerating the electron transfer, while the enzyme tagged gold nanoparticles provide signal amplification. Hybridization with the target DNA was studied by measuring the electrochemical signal response of horseradish peroxidase using differential pulse voltammetry. The calibration plot is linear in the 5.0 × 10−14 and 5.0 × 10−9 M concentration range, and the limit of detection is 2.2 × 10−15 M. The biosensor displays high selectivity and can differentiate between single-base mismatched and three-base mismatched sequences of DNA. The approach is deemed to provide a sensitive and reliable tool for highly specific detection of DNA.

Effect of mechanically damaged starch on wheat flour, noodle and steamed bread making quality

Abstract: Summary Wheat flour was ground in an ultrafine pulveriser to obtain different levels of damaged starch (DS). The effect of DS content on physicochemical properties of flour and quality attributes of Chinese noodles and northern-style Chinese steamed bread were investigated. Results showed that the degree of starch damage raised from 6.54% to 12.06% as grinding intensity increased from 0 to 130 Hz (P < 0.05). The falling number, sedimentation value, starch pastes' viscosity, dough proofing stability were negatively, while water absorption, pastes thermal stability, the degree of starch pastes and dough level were positively correlated with DS content, respectively (P < 0.05). The increase in DS content from 6.54% to 8.86% did not lead to a deterioration of texture characteristic, which might be attributed to the slight declining in hardness while enhancing in springiness and cohesiveness. The flour with DS content of 6.54–9.66% was suitable for steamed bread making.