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Abstract: Troxerutin supported palladium (TXT-Pd) catalyst was prepared readily by using one-step synthetic method. As-fabricated TXT-Pd catalyst was evaluated by means of fourier transform infrared spectrometer (FTIR), atomic absorption spectroscope instrument (AAS), and X-ray photoelectron spectrum (XPS). As-prepared catalyst possessed perfect catalytic properties to the Heck reaction of aryl halide with vinyl compounds in N2 atmosphere and the yields were up to above 95%. Particularly, the TXT-Pd catalyst could catalyze the Heck reaction of bromobenzene with low reaction activity and acrylic acid even at a low temperature 80°C even with a little amount of the catalyst. The remarkable interest was reusing properties, with which the yield was up to 36.7% after 7 times of the reusable catalyst. Moreover, TXT-Pd catalyst also showed high catalytic activity to the Heck reaction of substituted aryl halides with acrylic acid or styrene. [ABSTRACT FROM AUTHOR]

The magnetic, mechanical, and electronic properties of RhHx (x = 0, 0.25, 0.75, 1) have been investigated by first-principles calculations based on density functional theory. It is shown that RhHx (x = 0.25, 0.75, 1) in the cubic structure are magnetic except for Rh. The total magnetic moments of RhHx (x = 0.25, 0.75, 1) decrease with increasing content of H, which mainly results from the change of the Rh moments. The calculated elastic constants indicate that RhHx (x = 0, 0.25, 0.75, 1) in the cubic structure are mechanically stable. With increasing H content, the bulk modulus, shear modulus, and Young modulus gradually decrease except the bulk modulus of RhH. By means of the values of the B/G ratio, it is concluded that H doping improves the ductile properties of Rh. The strong hybridization between H-s and Rh-d is the origin of magnetism for RhHx (x = 0.25, 0.75, 1) and decreases with increasing H content. [ABSTRACT FROM AUTHOR]

This study proposes the generality of surface air temperature ( SAT)-atmospheric circulation feedback during high-temperature weather in late July 2003 over East China by using the Advanced Research Weather Research and Forecasting model ( WRF; Version 3) simulations with a succession of 24-h integrations, i.e. on a daily scale, the SAT increase leads to a weakened ridge of the western Pacific subtropical high in the lower troposphere (i.e. negative feedback), whereas it leads to a strengthened ridge in the upper troposphere (i.e. positive feedback) and vice versa. Additionally, using the balance equation of temperature, the feedbacks are clarified from the diurnal-variation perspective. This shows many complex details, e.g. the changes in geopotential heights are more complex than those in air temperatures, and the overall daily feedback appears to be dominated by the feedback during the phase with intense daytime surface heating. All of the WRF-modified land surface conditions can lead to large changes in the maximum, minimum, and average SATs over the mean diurnal scale, with generally larger differences induced by land surface schemes than those induced by initial soil moisture, suggesting that the SAT-circulation feedback can be greatly reduced (or amplified) by different land conditions over the diurnal weather scale and that diurnal variations could substantially contribute to longer timescale climate. [ABSTRACT FROM AUTHOR]

This paper discusses the necessity of using a transmission system to improve the energy efficiency of purely electric vehicles (EVs). The energy efficiency of an electric motor varies at different operating points to meet the output power demand. The three gear ratios of a transmission system can maintain the motor speed within a stable region with relatively high energy efficiency, while various vehicle speeds are needed. This work is based on a light EV prototype. The optimized gear ratios of this transmission result in a considerably reduced energy consumption of 9.3% compared with conventional EVs with single-speed reducers under the condition of the Urban Dynamometer Driving Schedule driving cycle. Thus, the transmission system is necessary to improve the energy efficiency of EVs. [ABSTRACT FROM AUTHOR]

Bone remodeling is essential for adult bone homeostasis. The failure of this process often leads to the development of osteoporosis, a present major global health concern. The most important factor that affects normal bone remodeling is the tightly controlled and orchestrated regulation of osteoblasts and osteoclasts. The present review summarized the recent discoveries related to osteoblast regulation from several signals, including transforming growth factor-β, bone morphogenetic proteins, Wnt signal, Notch, Eph-Ephrin interaction, parathyroid hormone/parathyroid hormone-related peptide, and the leptin-serotonin-sympathetic nervous systemic pathway. The awareness of these mechanisms will facilitate further research that explores bone remodeling and osteoporosis. Future investigations on the endogenous regulation of osteoblastogenesis will increase the current knowledge required for the development of potential drug targets in the treatment of osteoporosis. [ABSTRACT FROM AUTHOR]

The adsorption and wrapping process of a single flexible comb-like polymer to a single wall nanotube was studied by Molecular Dynamics simulation of a coarse-grained model. We varied the grafting density and length of the side chains, the radius of the nanotube and strength of interaction between the monomers of nanotube and side chains of polymer brush. We investigated the structural and dynamical characters of interactions of the nanotube-polymer composite, such as the effect of Lennard-Jones energy parameter ɛ and the nanotube radius on the adsorption behavior and how the wrapping conformation is affected by the structure of the polymer brush. The simulation results indicate that single comb-like polymer with flexible backbone tends to adsorb and wrap around the nanotube, when the interaction energy exceeds a critical value. The monomer adsorption ratio, interaction energy profiles and moment of inertia are obtained. The helical wrapping only occurs when the interaction energy is large enough. Also, the influence of the polymer structure on the conformational behavior is analyzed. This work underscores design elements important for engineering well-defined nanotube-polymer nanocomposite. [ABSTRACT FROM AUTHOR]

The electronic structures and optical properties of pure, N-doped and N-F codoped ZnO are investigated based on the density-functional theory. The calculations of the impurity formation energies and ionization energies for these systems indicate that incorporating the reactive donor F into N doped ZnO systems, not only enhances the N acceptor solubility, but also leads to a shallower N acceptor energy level in the band gap in p-type codoped ZnO. In addition, we analyze the imaginary part of the dielectric functions, and reflectivities for pure and N-F codoped ZnO. Compared with the pure ZnO, the remarkable feature in the dielectric function for N-F codoped ZnO is that there is a sharp peak in the low-energy region. [ABSTRACT FROM AUTHOR]

We use molecular dynamics simulations to investigate centipede-like polymers with stiff charged side chains, end-grafted to a planar wall. The effect of the grafting density and the Bjerrum length on the conformational behaviour of the brush is examined in detail. In addition, we make a comparison of centipede-like polyelectrolyte (CPE) brushes with neutral centipede-like polymer (NCP) and linear polyelectrolyte (LPE) brushes. At weak electrostatic interaction, the main chains of the CPE chains adopt a strongly stretched conformation, and the monomer density profiles of side chains exhibit a clear oscillatory behaviour. With increasing Bjerrum length, the CPE brush undergoes a collapse transition. Compared to the CPE brushes, the counterion condensation effect is stronger for the LPE brushes, regardless of whether the electrostatic interaction is weak or strong and of whether the grafting density is low or high. Additionally, it is shown that the architecture of the grafted chains makes a weak contribution to the counterion condensation at strong electrostatic interaction. We also find that the electrostatic repulsion between charged side chains can enhance the stiffness of the main chains and thus limit the range of movement of the free-end monomers. [ABSTRACT FROM AUTHOR]

Background:Volatile anesthetics cause Alzheimer's disease (AD)-like neuropathology in animals. We determined whether spine surgery under general anesthesia and anesthetic choice contributed to AD development. Methods: We searched the Clinical Data Repository of the University of Virginia for patients receiving spine surgery from January 1, 1992 to March 1, 2004. Patients with newly-diagnosed AD after the surgery but before March 1, 2009 (a minimal 5-year follow-up time after the surgery) were identified. Results: Among 10,161 spine surgery patients, 26 patients had new-onset AD. Univariate and multivariate logistic regression analyses of the data from these 26 patients and from 161 randomly selected spine surgery patients without new-onset AD suggest that increasing age is a risk factor for new-onset AD. Gender, anesthesia/surgery time, use of volatile anesthetics versus propofol (an intravenous anesthetic) and length of hospital stay were not different between patients with and without new-onset AD. Similar results were found with the case-control study. The frequency of new-onset AD in spine surgery patients was similar to that of patients who had never had a surgery. Conclusion: These results suggest that increasing age is a risk factor for AD in patients after spine surgery. Anesthesia/surgery may not be independent factors for AD development. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

In this paper, the output performances at 1331 nm in continuous-wave (CW) operation and the passive Q-switching regime of a Nd:Gd3Ga5O12(Nd:GGG) laser crystal have been investigated under pumping with diode lasers. A maximum CW output power of 1.5 W was reached at an incident pump power of 7.5 W; the overall optical-to-optical efficiency and the slope efficiency with respect to the pump power were 21.5% and 19.4%, respectively. The passive Q-switching regime was achieved with Co2+:LaMgAl11O19 (Co2+:LMA) saturable absorber (SA) crystals. A maximum average output power of 183 mW was recorded with a Co2+:LMA SA with initial transmission Ti of 90%. The pulse energy was 18.7 μJ and the pulse duration was 26.1 ns, which correspond to a pulse peak power of 0.7 kW. With a Co2+:LMA SA with Ti=81%, the average power decreased to 131 mW. However, the pulse energy increased to 21.4 μJ, the pulse duration was 16.4 ns and the pulse peak power increased to 1.3 kW. [ABSTRACT FROM AUTHOR]

We carried out coarse-grained molecular dynamics simulations to study the electrostatic adsorption of Janus nanoparticles which consist of oppositely charged hemispheres onto charged surfaces. Films with different conformations were formed by Janus nanoparticles. The effects of charge distributions of Janus nanoparticles and the surface on the film structures and dynamic adsorption behavior were investigated in detail. When the surface is highly charged, Janus nanoparticles tend to form single particles or small clusters. In these cases, the surface charge distribution plays an important role in regulating the process of electrostatic adsorption. When the amount of surface charges is reduced, the effect of charge distribution of Janus nanoparticles becomes significant. The repulsive interactions between Janus nanoparticles determine the aggregation behavior of Janus nanoparticles as well as the shape of adsorption structures, which tends to separate Janus nanoparticles and results in a thin adsorption layer and small clusters. When the number of positive charges on the surface of Janus nanoparticle approaches that of negative charges, Janus nanoparticles aggregate into large clusters close to charged surface. The charge distribution of Janus nanoparticles becomes pronounced in the process of electrostatic adsorption. [ABSTRACT FROM AUTHOR]

Coprocessing of bio-oil and petroleum fraction is a prospective way of bio-oil upgrading. The upgrading is a complex combination of kinetic and transport processes. An overall kinetic model was developed considering the internal diffusion and the catalyst deactivation in this paper. First, the parameters of intrinsic kinetics model were calculated by the experimental data obtained in a fixed-bed reactor with a fine powder catalyst particle (0.32 mm). Using the intrinsic kinetic parameters and gas–solid catalysis theory, an effectiveness factor model was developed to evaluate the effect of internal diffusion on coprocessing. Then the kinetic model rB=a×η×rB0was established based on the effectiveness factor model and the deactivation rate equation. The effectiveness factor η and liquid yields at different reaction conditions predicted by this kinetic model agreed closely with the experimental results. [ABSTRACT FROM PUBLISHER]

Symmetrical electrical double layer capacitors with ionic liquid potassium hydroxide (KOH)-based poly(acrylic acid) gel polymer electrolytes and activated charcoal electrodes were constructed and characterised. The optimised composition of gel polymer electrolytes exhibits high room temperature ionic conductivity of 0.46 S cm−1 with good mechanical and dimensional stability, which is suitable for their application as electrolyte in electrical double layer capacitors. Analysis shows that the maximum value of capacitance was 0.343 F cm−2, and this value corresponds to an energy density equal to 0.111 J cm−2. Electrical double layer capacitor exhibits large capacitance and high energy density. The results indicate that the gel polymer electrolyte used in our study is promising and is suitable as a solid electrolyte for high-performance all-solid-state electrochemical devices. [ABSTRACT FROM AUTHOR]

Our study focuses on the morphological parameters of bone growth and bone formation in Sprague–Dawley (SD) rats of different ages, using fluorochrome labelingin vivo. We concluded that bone longitudinal growth rate (LGR) and bone mineral apposition rate (MAR) were significantly increased in both the 1- and 3-month-old rats compared with the 6- and 14-month-old rats, and that of the parameters were significantly decreased in both the 6- and 14-month-old rats. Meanwhile, bone formation rate (BFR) and percent labeled perimeter (%L.Pm) peaked in 3-month-old rats, and were followed by remarkable decrease with aging. In the present study, static parameters including percent trabecular area (%Tb.Ar), trabecular thickness (Tb.Th) and trabecular number (Tb.N), contrary to previous reports, progressively increased, whereas trabecular separation (Tb.Sp) reduced with increasing age. Furthermore, bone mass increased for 14-month-old rats due to the significantly decreased bone turnover rate. [ABSTRACT FROM PUBLISHER]

Porous α-Co(OH) nanoflake array film is prepared by a facile hydrothermal synthesis method. The α-Co(OH) nanoflake array film exhibits a highly porous net-like structure composed of interconnected nanoflakes with a thickness of 15 nm. The pseudo-capacitive behaviour of the Co(OH) nanoflake array film is investigated by cyclic voltammograms (CV) and galvanostatic charge-discharge tests in 2 M KOH. The α-Co(OH) nanoflake array film exhibits high capacitances of 1017 F g at 2 A g and 890 F g at 40 A g as well as rather good cycling stability for supercapacitor application. The porous architecture is responsible for the enhancement of the electrochemical properties because it provides fast ion and electron transfer, large reaction surface area and good strain accommodation. [ABSTRACT FROM AUTHOR]