Data correction and verification of thermal simulation experiments under the influence of bulging belly

During the thermal simulation compression test, the formation of an obvious bulge in the specimen leads to a certain deviation between the calculated and actual values of the true stress. The finite element method was used to simulate the single-pass compression of specimens of 34CrNi3MoV steel and obtain the actual nonuniform deformation of the bulging belly during the compression process, and the results were applied to correct experimental flow curves. The results showed that the deformation conditions had a significant influence on the nonuniformity of the specimen deformation during the compression process, and all the modified flow curves were lower than the original ones. The size of the bulge and the metal flow line in the finite element simulation were consistent with the test results. The load value obtained by using the modified flow curve was similar to the load value measured in the test, which indicated that the modified flow curve was very close to the real flow force curve of the material. The method used to modify the flow force curve is simple and practical.

In situ preparation of double gradient anode materials based on polysiloxane for lithium-ion batteries

Although silicon has a high volumetric energy density as an anode material for Li-ion batteries, its volumetric expansion and sluggish Li+ migration kinetics need to be urgently addressed. In this work, cage-like structure materials (HRPOSS) derived from the in situ hydrogen reduction of polyhedral oligomeric silsesquioxane (T8-type POSS) were constructed as an Si@C anode for Li-ion batteries. Benefiting from the intriguing features of the Si/N double gradient and even-distributed silicon, HRPOSS-6 exhibited faint volume changes and fast ion-electron kinetics. Moreover, the uniformly immobilized nano-silicic and concentration gradient were favorable for accelerated ion migration. Therefore, HRPOSS-6 exhibited good electrochemical performances given that its cage structure could relieve the volume expansion. HRPOSS-6 demonstrated a high reversible capacity of 1814.1 mA h g-1 and long cycling performance after 200 cycles with 635 mA h g-1 at a current density of 0.5 A g-1. Accordingly, this Si/C/N composite exhibited great potential for high energy Li-ion batteries, where the corresponding full-cell (HRPOSS-6//LiNi0.6Co0.2Mn0.2O2) showed a cycle life of 200 cycles with over 80% capacity retention at rate of 1C. This work exploits the concentration gradients of dual elements for the capacity improvement of Si anodes and offers insight into the development of high-performance Si@C anode materials for advanced Li-ion batteries.

Study on Material Design and Corrosion Resistance Based on Multi-Principal Component Alloying Theory

This study mainly attempts to develop Mg-based alloy materials with excellent corrosion resistance by means of multi-principal alloying. The alloy elements are determined based on the multi-principal alloy elements and the performance requirements of the components of biomaterials. Mg₃₀Zn₃₀Sn₃₀Sr₅Bi₅ alloy was successfully prepared by vacuum magnetic levitation melting. Through the electrochemical corrosion test with m-SBF solution (pH7.4) as the electrolyte, the corrosion rate of alloy Mg₃₀Zn₃₀Sn₃₀Sr₅Bi₅ alloy decreased to 20% of pure Mg. It could also be seen from the polarization curve that when the self-corrosion current density is low, the alloy shows superior corrosion resistance. Nevertheless, with the increase in self-corrosion current density, although the anodic corrosion performance of the alloy is obviously better than that of pure Mg, the cathode shows the opposite situation. The Nyquist diagram shows that the self-corrosion potential of the alloy is much higher than that of pure Mg. In general, under the condition of low self-corrosion current density, the alloy materials display excellent corrosion resistance. It is proved that the multi-principal alloying method is of positive significance for improving the corrosion resistance of Mg alloys.

In vivo degradation and bone reaction of long-term fixation with a magnesium alloy made by twin-roll casting in a rat femur model

BACKGROUND

The effect of casting parameters on the microstructure and corrosion resistance of Mg alloys is still limited, especially in clinical animal experiments.

OBJECTIVE

We prepared a new magnesium rare earth alloy (Mg-Re, where Re is Ce or La) by vertical two-roll casting and Mg-A by further rolling. The microstructure characteristics, degradation behavior, and bone reaction of the two alloys were studied.

METHOD

Ti, Mg-Re, and Mg-A alloy plates were implanted in a rat femur model, and their degradation behavior was observed 48 weeks later.

RESULTS

In vivo experiments showed no significant changes around the femur in the Ti group, excluding external factors that may cause bone remodeling and lead to new bone formation. Mg-A induces more new bone formation than Mg-Re, which meets the necessary conditions to prevent pathological fracture. The specimen staining and sectioning showed that the liver and heart of rats implanted with magnesium alloys had no pathological changes and the cell structure was normal, similar to that of rats without a magnesium alloy.

CONCLUSION

Mg-A alloy has good healing potential as a biodegradable implant material.

The effect of medical biodegradable magnesium alloy in vivo degradation and bone response in a rat femur model with long-term fixation

BACKGROUND

It is of great significance to understand the effect of the different corrosion behaviors of magnesium (Mg) alloys manufactured using different casting methods and implanted with different methods on the long-term implantation to expand the application of Mg-based biomedical implants.

OBJECTIVE

The effects of four different casting and rolling speeds on the microstructure of an Mg-rare earth (Mg-Re) alloy were analyzed using electron backscatter diffraction (EBSD).

METHOD

Four Mg alloys were obtained using vertical two-roll casting (TRC) at 10 m/min, 16 m/min, 24 m/min, and 30 m/min, and their microstructure, corrosion behavior and bone reaction in vivo were studied.

RESULTS

The corrosion resistance of the alloy increases with an increase in casting speed and finer grain size of the cast-rolled parts. The Mg-Re alloys with TRC-10 m/min and TRC-30 m/min were selected for animal experiments. The two Mg alloys were made into metal rods and inserted into the rat femur to simulate the effect of Mg-Re on femoral healing under an injury condition. The rods were implanted for a long time to judge the effects of the Mg-Re alloy on the body. The TRC-30 m/min implants obtained highly mature new bone tissue in the case of bone injury.

CONCLUSION

The in vivo experiments showed that the corrosion resistance of the TRC-30 m/min implant was better than that of the TRC-10 m/min implant. After 32 weeks of implantation, there were no pathological changes in the liver, heart, or kidney of rats in the TRC-30 m/min group, and the cell structure was normal.

Biomass-Derived Porous Carbon with a Good Balance between High Specific Surface Area and Mesopore Volume for Supercapacitors

Porous carbon has been one desirable electrode material for supercapacitors, but it is still a challenge to balance the appropriate mesopore volume and a high specific surface area (SSA). Herein, a good balance between a high SSA and mesopore volume in biomass-derived porous carbon is realized by precarbonization of wheat husk under air atmosphere via a chloride salt sealing technique and successive KOH activation. Due to the role of molten salt generating mesopores in the precarbonized product, which can further serve as the active sites for the KOH activation to form micropores in the final carbon material, the mesopore-micropore structure of the porous carbon can be tuned by changing the precarbonization temperature. The appropriate amount of mesopores can provide more expressways for ion transfer to accelerate the transport kinetics of diffusion-controlled processes in the micropores. A high SSA can supply abundant sites for charge storage. Therefore, the porous carbon with a good balance between the SSA and mesopores exhibits a specific gravimetric capacitance of 402 F g^-1 at 1.0 A g^-1 in a three-electrode system. In a two-electrode symmetrical supercapacitor, the biomass-derived porous carbon also delivers a high specific gravimetric capacitance of 346 F g^-1 at 1.0 A g^-1 and a good cycling stability, retaining 98.59% of the initial capacitance after 30,000 cycles at 5.0 A^-1. This work has fundamental merits for enhancing the electrochemical performance of the biomass-derived porous carbon by optimizing the SSA and pore structures.

Exploring the Dual Characteristics of CH3OH Adsorption to Metal Atomic Structures on Si (111)-7 × 7 Surface

Metal atoms were deposited on an Si (111)-7 × 7 surface, and they were adsorbed with alcohol gases (CH₃OH/C₂H₅OH/C₃H₇OH). Initially, C_nH_2n+1OH adsorption was simply used as an intermediate layer to prevent the chemical reaction between metal and Si atoms. Through scanning tunneling microscopy (STM) and a mass spectrometer, the C_nH_2n+1OH dissociation process is further derived as the construction of a surface quasi-potential with horizontal and vertical directions. With the help of three typical metal depositions, the surface characteristics of CH₃OH adsorption are more clearly presented in this paper. Adjusting the preheating temperature, the difference of thermal stability between CH₃O^– and H⁺ could be obviously derived in Au deposition. After a large amount of H⁺ was separated, the isolation characteristic of CH₃O^– was discussed in the case of Fe deposition. In the process of building a new metal-CH₃O^–-H⁺ model, the dual characteristics of CH₃OH were synthetically verified in Sn deposition. CH₃O^– adsorption is prone to influencing the interaction between the metal deposition and substrate surface in the vertical direction, while H⁺ adsorption determines the horizontal behavior of metal atoms. These investigations lead one to believe that, to a certain extent, the formation of regular metal atomic structures on the Si (111)-7 × 7-CH₃OH surface is promoted, especially according to the dual characteristics and adsorption models we explored.

The role of protein restriction and interaction with antibiotics in the regulation of compensatory growth in pigs: growth performance, serum hormone concentrations, and messenger RNA levels in component tissues of the endocrine growth axis

The present study investigated the effects of protein restriction and antibiotics on the hypothalamus-pituitary-liver growth axis during the compensatory growth of growing and finishing pigs. Growth performance, serum hormones, and messenger RNA (mRNA) levels of hormones and their receptors in growth axis tissues were recorded for analyses. A total of 64 piglets (large white × Landrace × Duroc cross) with an initial weight of 10.07 ± 0.14 kg were randomly divided into 4 treatment groups of 16 piglets per group. The dietary treatments consisted of 2 protein levels (14% and 20%) and 2 antibiotic levels (no antibiotics and 20 mg/kg colistin sulfate with 50 mg/kg kitasamycin) in a 2 × 2 factorial arrangement. The study was performed over 30 d for the first stage (S1, restriction phase) and 74 d for the second stage (S2, realimentation phase). The 4 treatment diets were maintained throughout the duration in the restriction phase. The 4 groups were fed the same diet in the realimentation phase. The trial period totaled 104 d. Protein restriction decreased BW, average daily food intake, and ADG in weaning pigs (P < 0.01) and induced compensatory growth after feeding a normal diet during the growth of finishing pigs. Average daily gain increased during the last phase of compensatory growth (P < 0.01). Protein restriction increased serum GH and leptin (LEP) and the mRNA levels of liver IGF-1 receptor (IGF-1-R; P < 0.01) but decreased serum IGF-1 (P < 0.01) and the mRNA levels of liver GH receptor (GH-R; P < 0.01) and IGF-1 (P < 0.05) in weaning piglets. Serum GH was increased, but serum IGF-1 was decreased during the realimentation phase (P < 0.05). Antibiotics increased the mRNA levels of GHRH (P < 0.05) and decreased somatostatin (P < 0.01) in the hypothalamus of weaning pigs. Protein restriction and antibiotics had no interactions across the entire trial. In conclusion, the slowing of growth caused by early protein restriction may be compensated for in the later stages of pig raising, and the mechanism of compensation is related to the regulation of GH, IGF-1, GH-R, and IGF-1-R.

X-ray interference fringes from a weakly bent plane-parallel crystal with negative strain gradient

In the waves emitted from the entrance, back and lateral surfaces of a very weakly bent plane-parallel perfect crystal with negative strain gradient, X-ray interference fringes between two refracted beams with different hyperbolic trajectories were observed when the strain was very weak, of the order of 10⁻⁷.

Under the anomalous transmission condition in the Bragg mode, X-ray interference fringes were observed between two beams with different hyperbolic trajectories in a very weakly bent plane-parallel perfect crystal with negative strain gradient. The origin of the fringes was analysed based on the dynamical theory of diffraction for a distorted crystal. In the reflected beam from the entrance surface, the interference fringes were observed between once- and twice-reflected beams from the back surface. In the transmitted beam from the back surface, the interference fringes were observed between the direct beam and once-reflected beam from the entrance surface. In the emitted beam from the lateral surface, the interference fringes were observed between the beams after different numbers of reflections in the crystal. The multiply reflected beams were formed by a combined result of long propagation length along the beam direction with large divergence of the refracted beams when the strain gradient was negative. The period of these interference fringes was sensitive to very weak strain, of the order of 10⁻⁷.

Study on Formation Process and Models of Linear Fe Cluster Structure on a Si(111)-7 × 7-CH₃OH Surface

STM results showed that Fe atoms were deposited on a Si(111)-7 × 7 reconstructed surface, which was saturated with CH₃OH molecules. Fe atomic linear structure was composed of stable clusters and in-situ observed by the scanning tunneling microscopy (STM). The aim to improve its application of magnetic memory material, both formation process and models, has been explored in this paper. By combining surface images and mass spectrometer data, an intermediate layer model was established. In terms of thermal stability, the most favorable adsorption sites of CH₃OH were further explored. After that, Fe atoms were deposited on the Si(111)-7 × 7-CH₃OH surface, forming a linear cluster structure. On the one hand, a new Fe cluster model was put forward in this paper, which was established with height measurement and 3D surface display technology. This model is also affected by the evaporation temperature, which can be consistent with the atomic stacking pattern of face centered cubic structures. On the other hand, the slight height change suggested the stability of linear structures. Even in the condition of thin air introduction, Fe cluster showed a good performance, which suggested the possibility of magnetic memory application in the future. These investigations are believed to have, to a certain extent, increased the probability of forming Fe linear clusters on the surface of silicon substrate, especially according to the models and surface technology we adjusted.

A new study on the growth behavior of austenite grains during heating processes

In this paper, the effects of the heating temperature and holding time on the austenite grain growth of SCM435 steel were studied and analyzed in terms of the average, macro-axis and minor-axis size of the grains. The results indicated that the classical Sellars model was highly consistent for describing the growth stage of the new austenite but poorly described the initial nucleation-growth stage and stability stage of the austenite. A new model that expresses the average austenite grain growth of SCM435 steel was developed, and the values calculated based on this model were highly consistent with the actual measured values. The standard deviation and expected grain-size expressions increased as the heating temperature and holding time increased. The macro-axis and minor-axis size of the grains were linearly correlated with the average size, and the ratio of the macro-axis to the minor-axis size remained generally constant during grain growth. Furthermore, this paper provides a new way of thinking about heredity in materials science from the perspective of mathematical characteristics.

Simulation of the Continuous Casting and Cooling Behavior of Metallic Glasses

The development of melt spinning technique for preparation of metallic glasses was summarized. The limitations as well as restrictions of the melt spinning embodiments were also analyzed. As an improvement and variation of the melt spinning method, the vertical-type twin-roll casting (VTRC) process was discussed. As the thermal history experienced by the casting metals to a great extent determines the qualities of final products, cooling rate in the quenching process is believed to have a significant effect on glass formation. In order to estimate the ability to produce metallic glasses by VTRC method, temperature and flow phenomena of the melt in molten pool were computed, and cooling rates under different casting conditions were calculated with the simulation results. Considering the fluid character during casting process, the material derivative method based on continuum theory was adopted in the cooling rate calculation. Results show that the VTRC process has a good ability in continuous casting metallic glassy ribbons.

Genetic polymorphisms of loci D18S53, D18S59, and D18S488 in fetuses from a Chinese Tianjin Han population

We investigated the genetic polymorphisms of three short tandem repeat (STR) loci, D18S53, D18S59, and D18S488, on chromosome 18 in fetuses from a Chinese Tianjin Han population. Sixty-four villus samples and 374 amniotic fluid samples were collected from fetuses. Quantitative fluorescence polymerase chain reaction was performed to amplify the STR loci, followed by scanned electrophoresis and quantitative analysis of the fluorescence signals. Hardy-Weinberg equilibrium (HWE) analysis was performed based on the genotype distributions of the STR loci to obtain the following population genetic data: genotype frequency, heterozygosity of observation (HO), polymorphism information content (PIC), probability of discrimination power (PD), and probability of exclusion (PE). We detected 15, 13, and 15 alleles of D18S53, D18S59, and D18S488, respectively. The genotype frequencies were found to be in line with HWE. The HO values of the three loci, D18S53, D18S59, and D18S488, were 0.797, 0.847, and 0.792; the PIC values were 0.81, 0.75, and 0.73; the PD values were 0.944, 0.901, and 0.881; and the PE values were 0.593, 0.689, and 0.585, respectively. D18S53, D18S59, and D18S488 loci are good genetic markers of chromosome 18, and show potential for use in the prenatal genetic diagnosis of Edwards' syndrome.

Erratum: An X-ray diffractometer using mirage diffraction. Erratum

Errors in the article by Fukamachi, Jongsukswat, Ju, Negishi, Hirano & Kawamura [J. Appl. Cryst. (2014), 47, 1267–1272] are corrected.

Errors in the article by Fukamachi, Jongsukswat, Ju, Negishi, Hirano & Kawamura [J. Appl. Cryst. (2014), 47, 1267–1272] are corrected.

Molecular-like hierarchical self-assembly of monolayers of mixtures of particles

We present a technique that uses an externally applied electric field to self-assemble monolayers of mixtures of particles into molecular-like hierarchical arrangements on fluid-liquid interfaces. The arrangements consist of composite particles (analogous to molecules) which are arranged in a pattern. The structure of a composite particle depends on factors such as the relative sizes of the particles and their polarizabilities, and the electric field intensity. If the particles sizes differ by a factor of two or more, the composite particle has a larger particle at its core and several smaller particles form a ring around it. The number of particles in the ring and the spacing between the composite particles depend on their polarizabilities and the electric field intensity. Approximately same sized particles form chains (analogous to polymeric molecules) in which positively and negatively polarized particles alternate.

Blocking autophagy enhanced cytotoxicity induced by recombinant human arginase in triple-negative breast cancer cells

Depletion of arginine by recombinant human arginase (rhArg) has proven to be an effective cancer therapeutic approach for a variety of malignant tumors. Triple-negative breast cancers (TNBCs) lack of specific therapeutic targets, resulting in poor prognosis and limited therapeutic efficacy. To explore new therapeutic approaches for TNBC we studied the cytotoxicity of rhArg in five TNBC cells. We found that rhArg could inhibit cell growth in these five TNBC cells. Intriguingly, accumulation of autophagosomes and autophagic flux was observed in rhArg-treated MDA-MB-231 cells. Inhibition of autophagy by chloroquine (CQ), 3-methyladenine (3-MA) and siRNA targeting Beclin1 significantly enhanced rhArg-induced cytotoxic effect, indicating the cytoprotective role of autophagy in rhArg-induced cell death. In addition, N-acetyl-l-cysteine (NAC), a common antioxidant, blocked autophagy induced by rhArg, suggesting that reactive oxygen species (ROS) had an essential role in the cytotoxicity of rhArg. This study provides new insights into the molecular mechanism of autophagy involved in rhArg-induced cytotoxicity in TNBC cells. Meanwhile, our results revealed that rhArg, either alone or in combination with autophagic inhibitors, might be a potential novel therapy for the treatment of TNBC.

Formation of linearly linked Fe clusters on Si(111)-7 × 7-C2H5OH surface

The Fe atoms were deposited on the Si(111)-7 × 7 surface, which has been saturated with the C2H5OH molecules. Then, the Fe clusters were formed on Si(111)-7 × 7-C2H5OH surface and in situ observed by the scanning tunneling microscopy (STM). The STM images showed that with the increase of Fe clusters, the size of clusters was about 5 nm and they self-assembled in straightly linked chain crossing the step to lower or upper terrace. X-ray photoelectron spectroscopy (XPS) was in situ carried out on the surface of Fe/Si(111)-7 × 7-C2H5OH samples before and after the introduction of thin air (4.5 × 10(-2) Langmuir) into the STM chamber. The XPS results showed that the Fe clusters are stable in the abovementioned thin air condition at room temperature. Based on the STM and XPS results, the driving force making one-dimensional straightly linked chain structure might be the magnetic force of the Fe clusters. The formation of straightly linked Fe clusters chains suggests the formation of single magnetic domain Fe clusters.

PACS

07.79.Cz, 81.15.-z, 75.75.Fk.

An X-ray diffractometer using mirage diffraction

Some characteristics are reported of a triple-crystal diffractometer with a (+, −, +) setting of Si(220) using mirage diffraction. The advantages of this diffractometer are that its setup is easy, its structure is simple, the divergence angle from the second crystal is small and the energy resolution of the third crystal is very high.

Some characteristics are reported of a triple-crystal diffractometer with a (+, −, +) setting of Si(220) using mirage diffraction. The first crystal is flat, while the second and third crystals are bent. Basically, the first crystal is used as a collimator, the second as a monochromator and the third as the sample. The third crystal also works as an analyzer. The advantages of this diffractometer are that its setup is easy, its structure is simple, the divergence angle from the second crystal is small and the energy resolution of the third crystal is high, of the order of sub-meV.

Study on the optical property and surface morphology of N doped TiO₂ film deposited with different N₂ flow rates by DCPMS

N doped TiO2 films were deposited by direct current pulse magnetron sputtering system at room temperature. By using UV-Vis spectrophotometer and atomic force microscope, we studied the influence of N2 flow rate on the optical property and surface morphology of films. The results indicate that the optical property and surface morphology of N doped TiO2 film was dominated by the N2 flow rate. The mean absorbency in visible range of pure TiO2 films is near to 0%, which means that the pure TiO2 could hardly display the photocatalytic property in visible range. When N2 flow rate is 2 sccm, the mean absorbency in visible range of N doped TiO2 film could reach at 24%. In this case, the film could be used as photocatalyst induced by visible light. While with increasing N2 flow rate, the mean absorbency in visible range of N doped TiO2 film decreased abruptly. Especially when N2 flow rate exceeded 8 sccm, the mean absorbency in visible range of N doped TiO2 film decreased to about 0%, which is like pure TiO2 fimls.

Effect of stress corrosion cracking at various strain rates on the electrochemical corrosion behavior of Mg-Zn-In-Sn alloy

This study is aimed to determine the effect of stress corrosion with low strain rates on the electrochemical properties of alloy electrode. Stress corrosion cracking tests of Mg-Zn-In-Sn alloy in 3.5 wt.% sodium chloride solutions at 25°C were performed. The effects of the electrochemical properties under the stress corrosion with low strain rates were investigated. The microstructures of cross section were observed by optical microscope. The results showed that the ultimate tensile strengths of Mg-Zn-In-Sn alloy increased and the strain decreased as the strain rates increased. Open circuit potentials (OCP) of Mg-Zn-In-Sn alloy electrode possess stability and the loop currents (LC) were improved with the increasing of stress in the elastic zone. The variation of OCP and LC did not change with the increasing of strain-rate. The microstructure of cross section observing revealed the mechanism of OCP and LC changing.

Preparation of MgO/B₂O₃ coatings by plasma spraying on SUS304 surface and effects of heat-resistant

This study mainly deals with the preparation of MgO/B2O3 coatings by plasma spraying on the SUS304 surface and the effects of heat-resistant. The power materials of low thermal conductivity were selected to control the heat divergent performance of high temperature parts. The reticular micro-structure between the cover thermal layer and the substrate was prepared by using the plasma spraying method. The powder mixture of MgO and B2O3 were selected as spraying materials and the SUS304 was used as the substrate material. The MgO/B2O3 coating was prepared on the surface of the SUS304 to provide better cover thermal performance. The properties of the microstructures and the morphologies were studied by Optical Microscope, Scanning Electron Microscope, Electron Probe Microanalyzer, and X-ray Diffraction. The results showed that the cover thermal performance has been improved.

Recombinant human arginase induced caspase-dependent apoptosis and autophagy in non-Hodgkin's lymphoma cells

Arginase, an arginine-degrading enzyme, has gained increased attention recently as a new experimental therapeutics for a variety of malignant solid cancers. In this study, we found that recombinant human arginase (rhArg) could induce remarkable growth inhibition, cell cycle arrest, and caspase-dependent apoptosis in Raji and Daudi non-Hodgkin's lymphoma (NHL) cells through arginine deprivation. Interestingly, rhArg-treatment resulted in the appearance of autophagosomes and upregulation of microtubule-associated protein light chain 3 II, indicating that rhArg induced autophagy in lymphoma cells. Further study suggested that mammalian target of rapamycin/S6k signaling pathway may be involved in rhArg-induced autophagy in NHL cells. Moreover, blocking autophagy using pharmacological inhibitors (3-methyladenine and chloroquine) or genetic approaches (small interfering RNA targeting autophagy-related gene 5 and Beclin-1) enhanced the cell killing effect of rhArg. These results demonstrated that rhArg has a potent anti-lymphoma activity, which could be improved by in combination with autophagic inhibitors, suggesting that rhArg, either alone or in combination with autophagic inhibitors, could be a potential novel therapeutics for the treatment of NHL.

Strain distribution in an Si single crystal measured by interference fringes of X-ray mirage diffraction

Using the spacing and position of X-ray interference fringes accompanied by mirage diffraction, the strain distribution of a plane-parallel Si single crystal fixed at one end has been measured as a function of the distance l from the incident plane of the X-rays to the crystal edge. The measured strain gradients are proportional to l², which agrees with rod theory.

In X-ray interference fringes accompanied by mirage diffraction, variations have been observed in the spacing and position of the fringes from a plane-parallel Si single crystal fixed at one end as a function of distance from the incident plane of the X-rays to the free crystal end. The variations can be explained by distortion of the sample crystal due to gravity. From the variations and positions of the fringes, the strain gradient of the crystal has been determined. The distribution of the observed strain agrees with that expected from rod theory except for residual strain. When the distortion is large, the observed strain distribution does not agree with that expected from rod theory.

Direct acquisition of interferogram by stage scanning in electron interferometry

We present an electron holography technique to acquire an interferogram, that is, cosine image of phase distribution. The interferogram is constructed by shifting the specimen in one direction with a stage-scanning system and acquiring line intensities of holograms. Taking line intensities eliminates the carrier fringes in the holograms and yields the interferogram. Under phase object approximation, the object phase can be readily obtained from the interferogram without any reconstruction procedure. The spatial resolution of phase is determined independently of the fringe spacing, overcoming the limitation of conventional techniques based on the Fourier transformation method.

Moiré pattern from a multiple Bragg-Laue interferometer

In X-ray section topography of Si 220 diffraction in a multiple Bragg-Laue mode, a moiré pattern is observed when the incident beam is divided into two parts by inserting a platinum wire in the middle of the beam. The moiré pattern can be explained by the summation of two interference fringes corresponding to the two incident beams. The coherency of the X-rays from the bending-magnet beamline is estimated using the moiré pattern.

Composition and crystal structure of N doped TiO2 film deposited at different O2 flow rate by direct current sputtering

N doped Ti02 films were deposited by direct current pulse magnetron sputtering system at room temperature. The influence of 02 flow rate on the crystal structure of deposited films was studied by Stylus profilometer, X-ray photoelectron spectroscopy, and X-ray diffractometer. The results indicate that the 02 flow rate strongly controls the growth behavior and crystal structure of N doped Ti02 film. It is found that N element mainly exists as substitutional doped state and the chemical stiochiometry is near to TiO1.68±0.06N0.11±0.01 for all film samples. N doped Ti02 film deposited with 2 sccm (standard-state cubic centimeter per minute) 02 flow rate is amorphous structure with high growth rate, which contains both anatase phase and rutile phase crystal nucleuses. In this case, the film displays the mix-phase of anatase and rutile after annealing treatment. While N doped Ti02 film deposited with 12 cm(3)/min 02 flow rate displays anatase phase before and after annealing treatment. And it should be noticed that no TiN phase appears for all samples before and after annealing treatment.

Effects of Zn-In-Sn elements on the electric properties of magnesium alloy anode materials

A new magnesium alloy anode is based on an environmentally friendly electrode that contains none of mercury, lead and chromate, but it can enhance the electric properties of alloy significantly. Magnesium alloy adding eco-friendly elements Zn-In-Sn which was developed by orthogonal design were obtained by two casting methods. The effect of additive elements on performance of electrode material was studied. The effects of elements addition and casting method on electric properties and corrosive properties of Mg-Zn-In-Sn alloys were investigated by using electrochemical measurements, corrosive tests and observation of surface structure. The results show that Mg-Zn-In-Sn alloy anode has higher electromotive force and more stable work potential than that commercial magnesium alloy AZ91. It is suitable for anode material of magnesium battery for its small hydrogen evolution, less self-corrosion rate and easy to shed corrosive offspring off.

Influences of working pressure on properties for TiO2 films deposited by DC pulse magnetron sputtering

TiO2 films were deposited at room temperature by DC pulse magnetron sputtering system. The crystalline structures, morphological features and photocatalytic activity of TiO2 films were systematically investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and ultraviolet spectrophotometer, respectively. The results indicated that working pressure was the key deposition parameter influencing the TiO2 film phase composition at room temperature, which directly affected its photocatalytic activity. With increasing working pressure, the target self-bias decreases monotonously. Therefore, low temperature TiO2 phase (anatase) could be deposited with high working pressure. The anatase TiO2 films deposited with 1.4 Pa working pressure displayed the highest photocatalytic activity by the decomposition of Methyl Orange solution, which the degradation rate reached the maximum (35%) after irradiation by ultraviolet light for 1 h.

Electrochemical performance of magnesium alloy and its application on the sea water battery

The magnesium sea water battery belongs to a kind of reserved battery, which takes the active metal such as magnesium alloy as the anode based on the sea water as the electrolyte. Experiments of magnesium alloy sea water battery were carried out and its electrochemical performance was studied. Thin sheets of Mg-Al-Zn and Mg-Mn series of magnesium alloy were fabricated and used as the anode of magnesium battery. The discharging voltage and current were measured for different composition and thickness of Mg alloy sheet under various surface state, temperature as well as electrolyte. The effect of the temperature, the surface condition and the electrolyte to the electrical current and voltage were investigated. Anodic dissolution and mechanism of activation of Mg alloy anode were discussed based on surface microstructure observation. The feasibility to apply magnesium alloy sheet to highly effective sea water battery was verified.

Vaccination with IL-18 gene-modified, superantigen-coated tumor cells elicits potent antitumor immune response

OBJECTIVE

To investigate the induction of antitumor immune response by vaccination with interleukin-18 (IL-18) gene-modified, C215Fab-SEA-coated tumor cells.

MATERIALS

A B16-C215 cell clone stably expressing C215 antigen was established by transfecting the gene-encoding C215 antigen into B16 melanoma cells. The manipulated tumor cell vaccine was prepared with B16-C215 cells genetically modified with the IL-18 gene, coated with the fusion protein of SEA and the Fab region of C215 mAb (C215Fab-SEA) which specifically binds to the C215 antigen and then irradiated. C57BL/6 mice were vaccinated with IL-18 gene-modified, C215Fab-SEA-coated B16-C215 cells followed by tumor challenge. Tumor growth and survival time were observed. The expansion of CD4+, CD8+ cells in lymphocytes derived from draining lymph node was detected by FACS. Induction of CTL activity by vaccination was measured by 51Cr release assay.

RESULTS

IL-18 gene-modified, C215Fab-SEA-coated B16-C215 cell vaccine effectively stimulated lymphocyte proliferation and CD4+, CD8+ cell expansion in vitro. It was more immunogenic than B16-C215 cells genetically modified with IL-18 gene alone or B16-C215 cells coated with C215Fab-SEA alone. Immunization of the mice with the manipulated vaccine elicited protective immunity against the following tumor challenge of parental B16-C215 and wild-type B16 cells. Significant expansion of CD4+, CD8+ T cells was observed in the draining lymph node of the immunized mice when compared with that in unvaccinated mice. Higher CTL activity was induced in vaccinated mice than that in unvaccinated mice.

CONCLUSION

Vaccination with IL-18 gene-modified, C215Fab-SEA-coated tumor cells elicited potent antitumor response through induction of tumor-specific immune response.

Can head injury patients simulate malingering?

In the past few years, there have been many simulation studies on the efficacy of symptom validation tests. These typically involved nonclinical participants. This line of research was limited because the impact of the experience of head injury was not examined. Researchers failed to understand whether individuals with head injury would feign cognitive deficits on symptom validation tests as well as their nonclinical counterparts did. This study was designed to investigate simulation of memory deficits among the head injured on the Portland Digit Recognition Test (PDRT; Binder, 1993). Head injury patients, with and without corroborated brain damage, and a group of controls were involved to resemble clinical populations. Results showed that false negative rates ranged from 67% to 84% when participants were asked to feign memory difficulty on the PDRT. Head injury patients, regardless of corroboration of brain damage, were equally capable of feigning memory deficits on the PDRT as their nonclinical counterparts. Findings suggest that the additive value of symptom validity tests, such as the PDRT, can be limited for their use as malingering tests.

Activation-dependent changes in receptor distribution and dendritic morphology in hippocampal neurons expressing P2X2-green fluorescent protein receptors

ATP-gated P2X(2) receptors are widely expressed in neurons, but the cellular effects of receptor activation are unclear. We engineered functional green fluorescent protein (GFP)-tagged P2X(2) receptors and expressed them in embryonic hippocampal neurons, and report an approach to determining functional and total receptor pool sizes in living cells. ATP application to dendrites caused receptor redistribution and the formation of varicose hot spots of higher P2X(2)-GFP receptor density. Redistribution in dendrites was accompanied by an activation-dependent enhancement of the ATP-evoked current. Substate-specific mutant T18A P2X(2)-GFP receptors showed no redistribution or activation-dependent enhancement of the ATP-evoked current. Thus fluorescent P2X(2)-GFP receptors function normally, can be quantified, and reveal the dynamics of P2X(2) receptor distribution on the seconds time scale.

Dexamethasone inhibits the antigen presentation of dendritic cells in MHC class II pathway

Glucocorticoids (GC) are physiological inhibitors of inflammatory responses and are widely used as anti-inflammatory and immunosuppressive agents in treatment of many autoimmune and allergic diseases. In the present study, we demonstrated that one of the mechanisms by which GC can suppress the immune responses is to inhibit the differentiation and antigen presentation of dendritic cells (DC). DC were differentiated from murine bone marrow hematopoietic progenitor cells by culture with GM-CSF and IL-4 with or without dexamethasone (Dex). Our data showed that Dex, in a dose dependent manner, down-regulated surface expression of CD86, CD40, CD54 and MHC class II molecules by DC, but the expression of MHC class I, CD80, CD95 and CD95L were not affected. In addition, Dex-treated DC showed an impaired function to activate alloreactive T cells and to secrete IL-Ibeta and IL-12p70. Moreover, Dex inhibited DC to present antigen by MHC class II pathway. However, the endocytotic activity of DC was not affected. The inhibitory effect of Dex on the expression of costimulatory molecules and the antigen-presenting capacity of DC could be blocked by the addition of RU486, a potent steroid hormone antagonist, suggesting the requirement of binding to cytosolic receptors in the above-described action of Dex. Since DC have the unique property to present antigen to responding naive T cells and are required in the induction of a primary response, the functional suppression of DC by Dex may be one of the mechanisms by which GC regulate immune responses in vivo.

Constituents of red yeast rice, a traditional Chinese food and medicine

Detailed analyses were undertaken of the natural constituents of red yeast rice, a traditional Chinese medicine and food known for centuries to improve blood circulation. Preparation of red yeast rice following ancient methods by fermenting the fungal strain Monascus purpureus Went on moist and sterile rice indicated the presence of a group of metabolites belonging to the monacolin family of polyketides, together with fatty acids, and trace elements. The presence of these compounds may explain in part the cholesterol-lowering ability associated with this traditional Chinese food.

Long-term neuropsychological sequelae of severe burns

Eight patients who suffered severe burns and protracted periods of amnesia following those burns were evaluated for neuropsychological and neuropsychiatric problems between 6 months and 4 years following their accidents. All were found to have significant problems as evidenced in neuropsychological testing, activities of daily living, and reports from relatives. Findings on these burn patients with postburn amnesia were quite different from those of five burn patients who did not develop amnesia. Problems observed and reported in the burn-amnesia patients appeared to reflect clear neuropathological etiologies, which was not unexpected because their initial amnestic syndromes must also have been the result of significant central nervous system dysfunction. It is recommended that severe burn patients have neuropsychological, psychiatric, and neurological exams as part of routine postburn care.

Expression of a dominant negative TrkB receptor, T1, reveals a requirement for presynaptic signaling in BDNF-induced synaptic potentiation in cultured hippocampal neurons

We have developed a method to analyze the relative contributions of pre- and postsynaptic actions of a particular gene product in neurons in culture and potentially in slices using adenovirus-mediated gene transfer. A recombinant virus directed the expression of both a GFP reporter protein and TrkB.T1, a C-terminal truncated dominant negative TrkB neurotrophin receptor. When expressed in the presynaptic cell at synapses between embryonic hippocampal neurons in culture, the dominant negative TrkB.T1 inhibited two forms of synaptic potentiation induced by the neurotrophin brain-derived neurotrophic factor (BDNF): (i) greater evoked synaptic transmission and (ii) higher frequency of spontaneous miniature synaptic currents. These inhibition effects are not seen if the transgene is expressed only in the postsynaptic cell. We conclude that BDNF-TrkB signal transduction in the presynaptic terminal leads to both types of potentiation and is therefore the primary cause of synaptic enhancement by BDNF in these neurons.

[Therapeutic effects of combined suicide gene and cytokine gene therapy on erythroleukemia-bearing mice]

OBJECTIVE

To explore the antitumor effect of combined transfer of suicide gene and GM-CSF gene in erythroleukemia-bearing mice.

METHODS

Adenovirus harboring E. coli. cytosine deaminase (CD) gene (Ad-CD) and/or GM-CSF gene (Ad-GM-CSF) were used for the treatment of erythroleukemia-bearing mice. The mice were inoculated with FBL-3 erythroleukemia cells subcutaneously and 3 days later received Ad-CD followed by 5-fluorocytosine (5FC) treatment with or without Ad-GM-CSF.

RESULTS

The mice received Ad-CD/5FC and Ad-GM-CSF developed tumors more slowly and survived much longer than those received Ad-CD/5FC alone, Ad-GM-CSF alone, control virus Ad-LacZ/5FC or PBS. Combined transfer of CD gene and GM-CSF gene induced a higher specific CTL activity than control therapies did. Pathological examination illustrated that there were tumor necrosis and massive lymphocyte infiltration in the mice after the combined therapy.

CONCLUSION

Combined transfer of suicide gene and cytokine gene could synergistically inhibit the growth of erythroleukemia cells in the mice and induce tumor specific immunity of the host.

Dietary habits, food intake and functional outcomes in those with a history of Hansen's disease in Korea

This study shows that the nutrition and health status of ex-leprosy patients in Korea was marginal. Their nutrient intakes were low, especially from micronutrients which were associated with food from animal sources. Dietary quality was discriminated by food habits, such as skipping meals, irregularity of meals, food purchase and meal preparation. Dietary quality was best predicted by food habits followed by physical fitness and nutrition knowledge. Our subjects were nutrition-conscious, but they did not have accurate information. These findings suggest that our study population needs nutrition education.

[Antitumor effect of combined therapy with adenovirus-mediated CD suicide gene and interleukin 2 gene transfer and its immunological mechanism]

OBJECTIVE

Adenovirus harboring E. coli cytosine deaminase gene(AdCD) and adenovirus harboring interleukin 2 gene (AdIL-2) were used for the combined treatment of established tumors in vivo.

METHODS

C57BL/6 mice were inoculated with B16F10 melanoma cells and 3 days later received at the tumor site injections of AdCD and/or AdIL-2 followed by i.p. injection of 5-fluorocytosine (5-Fc) 300 mg/kg per day for 10 days.

RESULTS

Mice received combined therapy developed tumors more slowly and survived much longer when compared with mice treated with AdCD/5-Fc, AdIL-2, control adenovirus AdlacZ/5-FC, or PBS. To investigate the immunological mechanism of the antitumor effects of the combined treatment it was found to induce enhanced natural killer cell activity and specific cytotoxic T cell activity. FACS analysis demonstrated that AdIL-2/AdCD/5-Fc therapy increased the expression of H-2Kb and B7-1 on freshly isolated tumor cells. The CD4+ and CD8+ T cell infiltration in the tumor increased significantly.

CONCLUSION

Transfer of CD suicide gene plus 5-Fc combined with transfer of IL-2 gene synergistically inhibits the growth of melanoma in mice. Besides the cytotoxic effect of 5-Fc, specific and non-specific antitumor immunity might be responsible for the therapeutic effect. The combined therapy might have therapeutic potentials for human cancer.

In vivo gene therapy of murine melanoma mediated by recombinant vaccinia virus encoding human IL-2 gene

Direct gene transfer into somatic tissue iii vivo is a developing technology with potential application for cancer gene therapy. In this study, recombinant vaccinia virus encoding human IL-2 gene (rVV-IL-2) was used as a candidate vector in mediating iii vivo gene therapy. After rVV-IL-2 was expanded in VERO cells for 72 h, high titer (10(8)-10(10) PFU/ml) rVV-IL-2 were harvested. When 10(6) murine melanoma cells (F16-F10) were infected with rVV-IL-2, about 200 U/ml IL-2 activity was detected in the supernatants at 8 h, and the up-regulation of ICAM-1 and MHC-I expressions on the melanoma cells were observed. The treatment of murine melanoma model by local injection of rVV-IL-2 into the tumor site showed that rVV-IL-2 transfection significantly inhibited the tumor growth and prolonged the survival time of tumor-bearing mice. The splenocytes from rVV-IL-2 treated mice showed higher cytotoxicities of NK, LAK and CTL in comparison with those from the controls. These results suggest that in vivo transfection mediated by rVV-IL-2 has potential effectiveness in enhancing host immunity and would be a useful approach to cancer gene therapy.

Clinical observation on efficacy of electro-acupuncture therapy in hyperplasia of mammary glands and its effect on immunological function

Based on our work on electro-acupuncture therapy of hyperplasia of mammary glands and in order to observe further the relationship between immunological function and E2 in hyperplasia of mammary glands, we determined the change not only in immunological function before and after electro-acupuncture in 44 in-patients with hyperplasia of mammary glands and having the same menstruation date, but also in electro-acupuncture treated rat hyperplasia of mammary glands model. We found that there was decrease of immunological function in hyperplasia of mammary glands and this function could be remarkably enhanced by electro-acupuncture both in hyperplasia of mammary glands patients and in rat hyperplasia of mammary glands model. The mechanism implies it might be that the inhibitory effect on immunological function exerted by high concentration of E2 was lowered by electro-acupuncture, hence the immunological function was reinforced. The results of this study are important in exploration of both the pathogenesis of this disease and the mechanism of electro-acupuncture, and in reducing the incidence of breast carcinoma.

[Therapeutic effect of vaccinia virus secreting granulocyte-macrophage colony-stimulating factor on pulmonary metastatic melanoma]

A recombinant vaccinia virus containing and expressing the gene of murine granulocyte-macrophage colony-stimulating factor (VVGM-CSF) was tested for its antitumor activity. Murine pulmonary metastasis was established by injecting 2 x 10(5) B16F10 melanoma cells into tail vein of C57BL/6 mouse. Three days after B16F10 inoculation, VVGM-CSF or VVTK, a thymidine kinase gene deficient vaccinia virus, was injected intraperitoneally twice weekly for 2 weeks. Two weeks later mice were sacrificed and pulmonary metastasis foci counted. The results showed that VVGM-CSF treatment significantly decreased the number of pulmonary metastasis and prolonged the survival time of tumor-bearing mice (P < 0.01). Cytotoxic and phagocytic activities of peritoneal macrophages were found to be markedly elevated in mice treated with VVGM-CSF. Nitric oxide released from macrophages was also found to be increased. Based on these data, together with our previous results, we may speculate that continuous secretion of GM-CSF and activation of macrophages might partially explain the antitumor effects of VVGM-CSF.