Search

A monolithic macroporous silica (MMS) was prepared by using a pillared epoxy resin macroporous polymer as template. Polydopamine (PDA) as a spacer-arm polymer was modified on the surface of MMS for immobilization of Candida rugosa lipase (CRL), aiming to improve the performance of CRL and overcome the limitations of the immobilized enzymes on mesoporous materials and fine particles. The immobilization conditions and the properties of the immobilized CRL were investigated. The as-prepared monolithic macroporous materials were characterized by SEM, TEM, MIP, BET, FT-IR and TG-DTA. The results revealed that MMS possessed two sets of well-defined and uniform continuous macroporous channels (pore size of 300–500 nm), high mechanical strength, large pore volume and specific surface area, and that the PDA/MMS macroporous composite was constructed by PDA/SiO2/PDA nano-film with a thickness of about 50 nm. Because of its surface chemical properties and unique macropore structure, the PDA/MMS composite provided a simple, cost-effective way to enhance the catalytic activity of directly immobilized enzyme. The activity recovery of CRL–PDA/MMS was 201%, and the stability of the immobilized lipase was remarkably improved. Moreover, this biocatalyst can be easily recovered from the reaction system without centrifugation or filtration.

Amyloid β (Aβ) peptide can cause neurotoxicity in Alzheimer's disease (AD). The main purpose of the present study is to investigate the protective role of asiatic acid (AA) against Aβ25-35-induced neurotoxicity in neuronally differentiated PC12 cells. Differentiated PC12 cells were pretreated with 5, 10 or 20 μM AA before treatment with 20 μM Aβ25-35. The viability and apoptosis of differentiated PC12 cells were determined by MTT assay and Annexin V-FITC/PI double staining, respectively. The mitochondrial membrane potential (MMP) of differentiated PC12 cells was analyzed by JC-1 staining. The expression levels of proteins were detected by western blot analysis. We found that AA significantly increased the viability of differentiated PC12 cells but attenuated the mitochondria-mediated apoptosis dose-dependently when challenging with Aβ25-35. Besides, the results of western blot analysis showed that AA prevented IκBα degradation and p65 nuclear translocation, and promoted the phosphorylation of Akt and GSK-3β in Aβ25-35-treated differentiated PC12 cells. Moreover, LY294002, a specific PI3K inhibitor, was found to abolish the beneficial effects of AA on Aβ25-35-induced apoptosis and tau protein hyperphosphorylation. Our findings demonstrated that AA protects differentiated PC12 cells from Aβ25-35-induced apoptosis and tau protein hyperphosphorylation, which might be partially mediated by the activation of the PI3K/Akt/GSK-3β signaling pathway.

Ethylene signaling converges on the ETHYLENE-INSENSITIVE3 (EIN3)/EIN3-like (EIL) transcription factors to regulate a wide range of developmental processes in plants. EBF1/2 (EIN3-binding F-box protein 1 and 2) negatively regulate the ethylene signaling pathway by mediating the degradation of EIN3/EIL proteins. We uncovered previously that SlEBF1 and SlEBF2 are involved in ethylene response, plant senescence, and fruit ripening in tomato. The present study reports on the identification of a novel tomato F-box gene, designated as SlEBF2-like due that its encoded protein is greater similarity to SlEBF2. The SlEBF2-like promoter region contains three ethylene-response elements (EREs). SlEBF2-like is upregulated by ethylene and downregulated by ethylene inhibitors in tomato seedlings. It is dynamically expressed in flowers during bud-to-anthesis and anthesis-to-post-anthesis transitions, and at the onset of fruit ripening, suggesting its role in these situations where ethylene is required for flower opening and fruit ripening. SlEBF2-like overexpression leaded to fruit elongation, caused ripening and color change to start from fruit bottom and expand gradually to the pedicel, and strongly delayed fruit development and ripening in tomato. Our study indicates that the novel EBF gene, SlEBF2-like, is involved in fruit development and ripening via regulating the ethylene response in tomato.

Three types of surface nanostructures are fabricated on tungsten by adjusting azimuth angle θ of YVO4 birefringent crystal and laser parameters in experiment. Different surface structure morphologies are introduced and their features are investigated. The frequency characteristics of the three type laser-induced surface nanostructures are studied by the fast Fourier transformation (FFT). By varying the azimuth angle of YVO4 crystal we can not only convert one-dimensional (1D) grating-like structures into two-dimensional (2D) surface structures, but also control the structural anrangement. Compared with traditional two-step sequential processing method, the dual orthogonal pulses generating through YVO4 birefringent crystal can induce better periodical 1D grating-like stucrure. Moreover, the 2D microbumps are mainly dependent on the energy deposition effect from dual pulses. We also provide the underlying texturing mechanism of final periodic surface structures.

Nano-TiO 2 /chitosan/poly(N-isopropylacrylamide) (nano-TiO 2 /CS/PNIPAAm) composite hydrogel was prepared by a two-step polymerization method, and nano-TiO 2 can endow the composite hydrogel with photocatalytic activity. The nano-TiO 2 /CS/PNIPAAm composite hydrogel was characterized by FT-IR and SEM. The properties of dye adsorption and photocatalytic degradation were investigated. The results indicated that dye adsorption was strongly influenced by solution pH and the acid fuchsin (AF) removal rate was maximum at pH = 4. The dye removal rate decreased slightly with increasing temperature, and the composite hydrogel adsorbing AF dyes floated on the solution surface at 40 °C and could be readily removed from the aqueous solution. Kinetics analysis indicated that the dye adsorption by nano-TiO 2 /CS/PNIPAAm composite hydrogel conformed to pseudo-second order model. Moreover, nano-TiO 2 /CS/PNIPAAm composite hydrogel exhibited high efficiency of photocatalytic degradation for AF dyes, and AF dye removal rate reached 90.5% under UV irradiation for 160 min.

Analytically discussed is the evolution properties of optical vortices superimposed by Gaussian backgrounds. A kind of Tornado-like pattern is obtained after linear propagations, when the Gaussian background is wide enough compared with optical vortices. The same structures are exhibited by the intensity and the phase for the Tornado-like pattern, and the latter can be regarded as a clockwise rotation of the former. The gradient force exerted by the Tornado-like pattern upon micro-particles is investigated from the application point of view in optical tweezers. Compared to conventional optical vortices, the Tornado-like pattern shows the superior performance on the trapping ability for microparticles.

Idiopathic pulmonary fibrosis (IPF) is a lethal lung disease with few treatment options and poor prognosis. Emodin, extracted from Chinese rhubarb, was found to be able to alleviate bleomycin (BLM)-induced pulmonary fibrosis, yet the underlying mechanism remains largely unknown. This study aimed to further investigate the effects of emodin on the inflammation and fibrosis of BLM-induced pulmonary fibrosis and the mechanism involved in rats. Our results showed that emodin improved pulmonary function, reduced weight loss and prevented death in BLM-treated rats. Emodin significantly relieved lung edema and fibrotic changes, decreased collagen deposition, and suppressed the infiltration of myofibroblasts [characterized by expression of α-smooth muscle actin (α-SMA)] and inflammatory cells (mainly macrophages and lymphocytes). Moreover, emodin reduced levels of TNF-α, IL-6, TGF-β1 and heat shock protein (HSP)-47 in the lungs of BLM-treated rats. In vitro, emodin profoundly inhibited TGF-β1-induced α-SMA, collagen IV and fibronectin expression in human embryo lung fibroblasts (HELFs). Emodin also inhibited TGF-β1-induced Smad2/3 and STAT3 activation, indicating that Smad2/3 and STAT3 inactivation mediates emodin-induced effects on TGF-β1-induced myofibroblast differentiation. These results suggest that emodin can exert its anti-fibrotic effect via suppression of TGF-β1 signaling and subsequently inhibition of inflammation, HSP-47 expression, myofibroblast differentiation and extracellular matrix (ECM) deposition.

In this work, the geometry, stability and electronic structures of atomic palladium chains supported on the NiAl(1 1 0) surface have been investigated by using the first-principles calculations. Palladium monomer strongly adsorbed at Ni Ni and Al Al bridge sites bonding with the two most neighboring Ni atoms. There is competitive mechanism between interactions of Pd Pd and interactions between Pd and NiAl substrate for Pd ad-chains. We also observe the interactions of resonance states give rises to a band of resonance states, which is mainly related to the overlap of 5sp orbital of adjacent Pd atoms. Finally, we demonstrated that the atomic spacing in Pd ad-chains and adsorption sites had significant influences to the bandwidth of resonance band. These results may have potential applications in the fields of nanoelectronics and nanoscale catalysts.

We theoretically calculate the resonant (1 + 1) two photon transition probability in the Rubidium (Rb) atom by the θ − phase shaped pulses. The results show that the resonant two photon transition probability can be enhanced by the θ − phase shaped pulses. The resonant two photon transition amplitude in complex plane have different distributions for different phase step position, but those distributions meet in a point which corresponds the transition amplitude of transitions-limited pulse and the shaped pulses with θ = 0. Moreover, the transition amplitude of on-resonant and near-resonant part is calculated to explain the two photon transition amplitude distribution and reveal the physical control mechanism.

As an herbicide, oryzalin (ORZ) is extensively used to control the growth of weeds, whereas excessive ORZ is harmful to human beings. Therefore, it is imperative for its quantitative detection. However, numerous efforts have been focused on noble-metal materials in electrochemical sensing, increasing the application cost. In this study, CoMoS/O-MWNTs hybrid with wrinkled nanosheets, as a non-noble metal electrocatalyst, is successfully synthesized by hydrothermal method. The CoMoS/O-MWNTs is cost-effective and has the elevated stability and catalytical activity, which can be attributed to the combination between CoMoS and O-MWNTs through O element strengthens strong coupling interaction of Co Mo. The platform possesses the wide linear detecting range of 0.48–22 μM and 22–85 μM, which is wider than previous reports. Thus, the excellent electrochemical property demonstrates CoMoS/O-MWNTs is an effective electrocatalyst for the reduction of ORZ.

Black hierarchical porous ZnO was prepared by oxidation of nano-porous Zn/ZnO sample obtained from the Al-Zn alloy etched in an NaOH aqueous solution, and was characterized by XRD, SEM, TEM, BET, EDS and UV-Vis spectrophotometer measurements. The results showed that the ZnO appeared black in the sunlight and its reflectivity was approximately 19.5% in the wavelength range from 370 nm to 700 nm. The Black ZnO sample exhibited a hierarchical porous structure consisting of nanosheets with uniformly distributed mesopores , that gives rise to a high specific surface area of about 36 m2/g. Compared to the ZnO nanopowders and TiO2 (P25), black porous ZnO exhibited excellent photocatalytic activity in the degradation of a methyl orange solution under visible light.

A new and facile method has been developed in this study for the fabrication of multicore–shell type nanoreactor. On the basis of the characterization results from X-ray diffraction, scanning and transmission electron microscopy, Raman and X-ray photoelectron spectroscopy, and N2 adsorption/desorption analysis, it has been proved that ultrasmall iron oxide particles (∼10 nm) were firstly encapsulated in the matrix of polystyrene spheres via a microemulsion-polymerization-assisted approach, and then were introduced as movable cores inside mesoporous SiO2 shell. The size of iron oxide particles retained almost unchanged even during the calcination procedure in air, indicating high thermal stability, due to the protection of polystyrene matrix. The obtained nanoreactor was applied as an effective heterogeneous catalyst for total oxidation of methylene blue with aqueous hydrogen peroxide and the ultrasmall iron oxide particles within the hollow interior proved to be active sites for such reaction. Mesoporous SiO2 shell not only protects the nanometer-sized iron oxide particles against leaching from the nanoreactor into reaction solution, but also enriches the reactant molecules around multiple ultrasmall iron oxide cores and thus enhances the catalytic activity and reaction rate. Importantly, the nanoreactor can be easily recovered by external magnetic field and reused in successive catalytic cycles without significant loss of activity.

In this paper, we theoretically demonstrate that the fine green emission in Er3+ ion system can be effectively controlled by the shaped ultra-short laser pulses with a π phase modulation. Our results show that the two photon transition probabilities of two excited states are effectively tuned by the single π phase modulation of 800 nm or 1600 nm laser pulses. By combining π phase modulation of the two exciting pulses, one excited state can be populated at maximum value, while the other state population can be widely tuned from zero to the maximum value. Furthermore, we explain the physical control mechanism of fine green emission by considering the second-order power spectrum of the shaped pulses. These schemes can be applied to realize the selective population of multiple excited states.

Multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE), are chronic neuroinflammatory autoimmune diseases characterized by axonal loss, demyelination and neurodegeneration of the central nervous system (CNS). Overactivation of CD4(+)T cells, especially the Th1 and Th17 subsets, is thought to play a causal role in this disease. In this study, we investigated the immunomodulatory effects of IFN-β treatment in EAE. IFN-β significantly inhibits disease severity, and decreases levels of CCR2, CCR4, CCR5, CCR6 and CXCR3 in the CNS. This was associated with fewer Th1/Th17 cells expressing these chemokine receptors. Furthermore, levels of their corresponding ligands CCL2, CCL3, CCL4, CCL5, CCL20, CCL22 and CXCL10 were also reduced, coinciding with reduced CNS inflammation and demyelination. Chemokine expression significantly correlated with disease severity. Furthermore, we demonstrate that IFN-β reduces CCL2/CCL5 induced-T cell migration by inhibiting p38-MAPK and ERK1/2 activation. Our results reveal that IFN-β reduces the expression of chemokines and chemokine receptors expressed by encephalitogenic Th1/Th17 cells, thereby decreasing their migration into the CNS.

Discussed analytically is the dynamics of a vortex dipole embedded in an elliptic Gaussian beam. Two opposite charged vortices of the vortex dipole can repel or attract each other, depending on whether their initial spacing larger or smaller than the critical value. While, stable vortex dipole with invariant spacing is predicated to exist at critical initial spacing. The critical spacing is dramatically related with the host elliptic beam. Furthermore, the dynamics of the vortex dipole can result in an off-axis propagation of optical beams, with propagating directions normal to the orientations of the vortex dipole. The optical beam exhibits larger off-axis velocity when the vortex dipole is parallel to the major axis of the host elliptic beam. The off-axis velocity can be further enhanced by increasing the ellipticity of host beams. The theoretical results can provide a controllable approach to change the propagating directions of optical beams by adjusting the initial spacing of vortex dipoles.

Discussed is the dynamics of optical vortices carrying multi-topological charges, which are nested in optical envelopes with non-circular symmetric amplitudes and phases. As a result of the non-circular symmetry either in amplitudes or in phases, the vortices can split in pairs from the centers of the host beams. During the splitting process of every constituent vortex, its carried integer charges evolve into fractional ones. Furthermore, the overall rotations of the host optical envelopes are found to happen in the splitting process. The theoretical results may find potential applications in beam shaping and engineering.

Improving the site accessibility of molecularly imprinted polymer (MIP) is one of the biggest challenges for application of MIP in solid-phase extraction (SPE). Hierarchically imprinted mesoporous silica polymer was prepared with semicovalently bond imprinting methods based on MCM-41 and SBA-15 mesostructures, aiming to improve the site accessibility of MIP and increase the efficiency of molecularly imprinted-SPE. Characterization and performance tests of the obtained products revealed that molecularly imprinted SBA-15 (MIP-SBA-15) not only retained the mesoporous structure of SBA-15, but also displayed excellent selectivity of MIP to the target molecule. As the MIP-SBA-15 were adopted as the adsorbents of solid-phase extraction for detecting bisphenol A in spiked water samples, the recoveries of spiked samples more than 87%, which reveals that the molecularly imprinted SBA-15 were efficient SPE adsorbents for bisphenol A.

In this paper, we investigate the cooperative beamforming (BF) design problem for amplify-and-forward relay networks that are operating over frequency-selective channels using Orthogonal frequency division multiplexing (OFDM) signaling. We focus on the time-domain (TD) BF due to the lower implementation complexity and lower feedback requirement from the destination. Our aim for the BF design is maximizing the minimum signal-to-noise-ratio (SNR) over all subcarriers at the destination. We show that the BF designs lead to non-convex problems generally. Three approaches to approximate these problems into convex problems are proposed. In the first approach, semidefinite relaxation (SDR) techniques with randomization methods are applied. In the second approach, an existing iterative method for cooperative beamforming of multi-group multicasting (MGM) relay networks is extended to solve our problem. The third approach consists of improving the second approach by appropriately choosing the initial phase rotation. Simulation results demonstrate that the third approach always outperforms the other two approaches. Moreover, the performance of the second approach is close to that of the first approach when the filter length is relatively small. When a longer TD filter is employed, the second approach outperforms the first approach.

Novel media–sludge-fly ash ceramic particles (SFCP) employed in an upflow lab-scale A/O BAF were investigated for synthetic wastewater treatment. The influences of hydraulic retention time (HRT), air–liquid ratio (A/L) and recirculation on the removals of chemical oxygen demand (CODcr), ammonia ( NH 4 + – N ) and total nitrogen (TN) were discussed. The optimum operation conditions were obtained as HRT of 2.0 h, A/L of 15:1 and 200% recirculation. Under the optimal conditions, 90% CODcr, more than 98% NH3–N and approximately 70% TN were removed. The average consumed volumetric loading rates for CODcr, NH 4 + – N and TN with 200% recirculation were 4.06, 0.36 and 0.29 kg (m3 d)−1, respectively. The CODcr and TN removal mainly occurred in the anoxic zone, while nitrification was completed at the height of 70 cm from the inlet of the bottom due to a suitable column layout of biological aerated filter (BAF). The characteristics of wastewater and backwashing affected TN removal to a large degree. In addition, the features of media (SFCP) and synthetic wastewater contributed to a strong buffer capacity in the BAF system so that the effluent pH at different media height fluctuated slightly and was insensitive to recirculation.