Search

This paper introduced a kind of micro/nanomotion platform. The platform mainly includes 12 flexible hinges, piezoelectric ceramic driver (PZT), motion platform (loaded platform), pre-tightening force adjusting screw and so on. The orthogonal experiment method was used to the output displacement of the micro/nanoplatform. The relationship among the voltage, pre-tightening force and output displacement of the platform was analyzed. The factor level table of the output displacement was produced. The experimental system was established by Laser interferometer and pressure sensor, then the output displacement was obtained when the voltage ranges from 0V to 150V on the condition of every force (20N, 40N, 60N, 80N and 100N). The experimental result lays the foundation for the regression analysis of the output displacement of the platform.

Protein O-glycosylation is an important post-translational modification in all organisms, but deciphering the specific functions of these glycans is difficult due to their structural complexity. Understanding the glycosylation of mucin-like proteins presents a particular challenge as they are modified numerous times with both the enzymes involved and the glycosylation patterns being poorly understood. Here we systematically explored the O-glycosylation pathway of a mucin-like serine-rich repeat protein PsrP from the human pathogen Streptococcus pneumoniae TIGR4. Previous works have assigned the function of 3 of the 10 glycosyltransferases thought to modify PsrP, GtfA/B, and Gtf3 as catalyzing the first two reactions to form a unified disaccharide core structure. We now use in vivo and in vitro glycosylation assays combined with hydrolytic activity assays to identify the glycosyltransferases capable of decorating this core structure in the third and fourth steps of glycosylation. Specifically, the full-length GlyE and GlyG proteins and the GlyD DUF1792 domain participate in both steps, whereas full-length GlyA and the GlyD GT8 domain catalyze only the fourth step. Incorporation of different sugars to the disaccharide core structure at multiple sites along the serine-rich repeats results in a highly polymorphic product. Furthermore, crystal structures of apo- and UDP-complexed GlyE combined with structural analyses reveal a novel Rossmann-fold "add-on" domain that we speculate to function as a universal module shared by GlyD, GlyE, and GlyA to forward the peptide acceptor from one enzyme to another. These findings define the complete glycosylation pathway of a bacterial glycoprotein and offer a testable hypothesis of how glycosyltransferase coordination facilitates glycan assembly.

This paper introduced a kind of fast tool servo (FTS). Base on in the frame rack, flexible hinge, piezoelectric ceramic driver, tool base, diamond tools and so on. Laser interferometer is used for displacement measuring of the fast tool servo. The structure simulation was done to the FTS and the nature frequency was obtained. The output displacement of FTS was measured by Laser interferometer. Four kinds of different sin wave sign were given and the frequency of driving voltage ranged from 10Hz to 400 Hz. The relation of the displacement and the driving voltage frequency and the relation of displacement and the driving voltage had been established by experiment.

Modal analysis was done to steel shaft and rubber shaft, and their top ten orders of nature frequency were obtained. The lowest nature frequency of steel shaft is 64HZ and the rubber steel’s is 2.2463HZ. Doppler vibration measurement was done to main shaft of paper advance mechanism and the time domain signal and frequency domain signal were obtained when the rotational speed is 80, 160, 240, 320, 400 Rpm. The frequency and amplitude were obtained by signal analysis. It proves that the nature frequency of steel main shaft is much higher than measuring result, but the seventh and eighth order nature frequency of rubber material is in accord with measuring result of laser doppler vibration.

It introduced the application of the behavioral modeling technique and the finite element analysis to optimize the packaging container structure design. Here showed an example about a design process of a certain volume beverage bottle. Firstly, through determining the design targets, analysis the design parameters and iterated calculation for these parameters, the construction and dimension of the container which meet the design targets can be obtained initially. On this basis, the stress on the container can be emulated using finite element analysis. After the strength factor to be considered, the design proposal of the packaging container is the optimized one finally.

One-dimensional nanomaterials and their assemblies attract considerable scientific interest in the physical, chemical, and biological fields because of their potential applications in electronic and optical devices. The interface-assembly method has become an important route for the self-assembly of nanoparticles, nanosheets, nanotubes, and nanorods, but the self-assembly of ultralong nanowires has only been successful using the Langmuir–Blodgett approach. A novel approach for the spontaneous formation of highly aligned, ultralong Ag nanowire films at the oil–water–air interface is described. In this approach, the three-phase interface directs the movement and self-assembly process of the ultralong Ag nanowires without the effect of an external force or complex apparatus. The ordered films exhibit intrinsic large electromagnetic fields that are localized in the interstitials between adjacent nanowires. This new three-phase-interface approach is proven to be a general route that can be extended to self-assemble other ultralong nanowires and produce ordered films.

Background Genetic variants of the genes encoding HIV-1 co-receptors and their ligands, CCR5-Δ32, CCR5m303A, CCR2-64I and SDF1-3′A, are implicated in the susceptibility to HIV-1 infection, and the prevalence of these mutations varies by ethnicity. However, little is known about their distribution in Uighurs. Objectives This study aimed at characterizing the frequency of these HIV-related gene variants in a high-risk Uighur population. Study designs A total of 251 HIV-1 seropositive and 238 seronegative high-risk Uighurs were recruited and their genotypes of CCR5-Δ32, CCR5m303A, CCR2-64I and SDF1-3′A were analyzed by PCR and PCR-ligase detection reaction (PCR-LDR). Results The allelic frequency of CCR5-Δ32, CCR5m303A, CCR2-64I and SDF1-3′A was 4.40%, 2.66%, 25.66% and 57.36%, respectively, in this population. Apparently, the Uighur population has low frequency of CCR5-Δ32 and CCR5m303A, but high frequency of CCR2-64I and SDF1-3′A. While there was no significant difference in the frequency of CCR5-Δ32, CCR2-64I and SDF1-3′ A between HIV-1 seropositive and seronegative groups the frequency of CCR5m303A in HIV-1 seropositive group was significantly higher than that in seronegative group ( P = 0.006, OR = 3.982 and 95%CI 1.514–10.476). Conclusions Our data suggest that the CCR5-Δ32, CCR2-64I and SDF1-3′A variants may have limited effect on protecting from HIV-1 infection in Uighurs. Rather, the CCR5m303A may be associated with the risk for HIV-1 infection in high-risk Uighurs.

To investigate penetration characteristics of artemether and the effect of different permeation enhancer on transdermal permeation of artemether through rat skin.The permeation experiments were performed using rat skin on modified Franz diffusion cells in vitro. The concentrations of artemether in receptor compartment at specified time points were determined by HPLC.The permeating ratio through human skin of artemether solution was Js (2.78 +/- 0.78) microg x cm(-2) x h(-1), the quantity of drug penetrated through and accumulated in the skin by the end of the experiment were (69.07 +/- 3.01) microg x cm(-2), (58.93 +/- 3.56) microg x cm(-2) respectively. Four different permeation enhancers can improve the transdermal permeation of artemether.Artemether have the potential to be developed to new transdermal preparation.

To compare the pharmacokinetics and tissue distribution of alpha-asarone in lipid emulsion and aqueous solution for injection and study the feasibility of lipid emulsion of alpha-asarone as the parenteral drug delivery system.HPLC was used to determine the drug concentration in rat plasma and mice tissues after intravenous (i.v.) administration of lipid emulsion and aqueous solution of alpha-asarone at a single dose (40 mg x kg(-1)), respectively.The plasma concentration-time profiles of lipid emulsion and aqueous solution of alpha-asarone after intravenous administration of them are similar and the drug concentration-time data were fitted to a two-compartment open model. The results of tissues distribution showed that distribution contents of alpha-asarone from lipid emulsion and aqueous solution in vivo are similar in lungs but lipid emulsion increased the uptake in livers and spleens, and decreased the uptake in hearts and kidneys for alpha-asarone.The plasma concentration-time profiles of alpha-asarone in lipid emulsion and aqueous solution are similar, but lipid emulsion significantly altered the tissue distribution of alpha-asarone, which may be beneficial to decrease its potential toxicity to heart and kidney.

PLGA nanoparticles simultaneously loaded with vincristine sulfate (VCR) and quercetin (QC) were prepared via O/W emulsion solvent evaporation. Six independent processing parameters and PLGA characteristics were assessed systematically to enhance the incorporation of the dual agents with different properties (VCR and QC, hydrophilic and hydrophobic molecule, respectively) into PLGA nanoparticles and control particle size. Approaches investigated for the enhancement of drug entrapment efficiencies and the controlling of particle size included the influence of the molecular weight (MW) of PLGA and the lactide-to-glycolide (L:G) ratio of PLGA, PLGA concentration, PVA concentration, initial QC content, acetone-to-dichloromethane (A/D) volume ratio, aqueous phase pH and aqueous to organic phase (W/O) volume ratio. The nanoparticles produced by optimal formulation were submicron size (139.5 ± 4.3nm, n = 3) with low polydispersity index (0.095 ± 0.031, n = 3). Nanoparticles observed by transmission electron microscopy (TEM) showed extremely spherical shape. The entrapment efficiencies determined by high performance liquid chromatography (HPLC) by ultracentrifuge method were 92.84 ± 3.37% for VCR and 32.66 ± 2.92% for QC (n = 3). The drug loadings were 0.0037 ± 0.0001% for VCR and 1.36 ± 0.12% for QC (n = 3).