Transmission Electric Microscope Research Articles

High glucose-induced injury in human umbilical vein endothelial cells is alleviated by vitamin D supplementation through downregulation of TIPE1

BackgroundDiabetes mellitus (DM) and its associated vascular complications have become a worldwide health concern. The effects and mechanism of vitamin D supplementation on endothelial function under high glucose condition remain elusive.MethodsHuman umbilical vein endothelial cells (HUVECs) were treated with 35 mM glucose, then 100 nM vitamin D were added. Transwell migration assay, CCK-8, immunofluorescence, flow cytometry, autophagy flux and transmission electric microscope were performed.ResultsVitamin D reduced apoptosis, promoted migration and enhanced viability of HUVECs, decreased TIPE1 (Tumor necrosis factor-α-induced protein 8-like 1) under high glucose conditions. Overexpression of TIPE1 reverses the effects of vitamin D by increasing ROS production, inflammation, cell apoptosis, and suppressing autophagy, cell migration and viability. And vitamin D negatively correlated with TIPE1 mRNA level in DM patients.ConclusionsVitamin D reverses the harmful effects of high glucose on HUVECs by reducing TIPE1 expression. And vitamin D supplementation could help to alleviate high glucose-induced injury in type 2 diabetes mellitus patients with microvascular complications.

Influence of static magnetic field on the heterogeneous nucleation behavior of Al on single crystal Al2O3 substrate

This paper investigates the heterogeneous nucleation behavior of Al on single crystal Al2O3 substrate under the influence of static magnetic field (SMF). The nucleation temperature of the Al melt on the substrate was measured to decrease ~2.9°C under SMF, i.e. the undercooling was enhanced with the application of SMF. Using electric back-scatter diffraction (EBSD) and high-resolution transmission electric microscope (HRTEM), the interfacial crystal orientation matching of Al/Al2O3 was found to change dramatically, from {110}[011]Al~//{101¯0}[0001]Al2O3 without SMF to ~11.4o between {110}[1¯12]Al and {101¯0}[0001]Al2O3 under SMF, indicating that the SMF can increase the lattice misfit of Al/Al2O3 interface. The lattice matching deviation caused by SMF was supposed to lead to the increase of interfacial free energy of the nucleus/substrate interface, and thus the formation of critical nucleus and the undercooling were modified. The results demonstrate that SMF is capable of influencing the heterogeneous nucleation behavior of the melt.

Precipitation Behaviors of a New Antibacterial Maraging Stainless Steel for Medical Instruments

A new antibacterial maraging stainless steel with high hardness and good antibacterial property has been developed. The hardness of the new maraging stainless steel with a cold rolling deformation of 85 pct reaches the peak about 58.5 HRC after aging heat treatment, which is mainly due to the ɛ-Cu and Ni-, Al-, Ti-rich precipitates. Reverted austenite transformed from the martensite is responsible for the decrease of hardness when aging at higher temperature. Three-dimensional atom probe (3DAP) and transmission electric microscope (TEM) were used to investigate the precipitates formed in the martensite matrix after aging at 713 K for 4 hours. The ɛ-Cu and Ni-, Al-, Ti-rich precipitates distribute uniformly in the martensite matrix, and the Ni-, Al-, Ti-rich precipitates are nucleated on the Cu-rich precipitates. Because of the ɛ-Cu precipitates, the new maraging stainless steel possesses an excellent antibacterial property with the rate about 95.08 pct, which has a wide application prospect on scalpels and surgical needles.

Optimization of the Amount and Molecular Weight of Dispersing Agent PEG During the Co-Precipitation Preparation of Nano-Crystalline C-YSZ Powder.

Single-phase nano-crystalline yttria-stabilized zirconia (YSZ) powder was prepared by co-precipitation method using zirconium oxychloride (ZrOCl₂ · 8H₂O) and yttrium nitrate (Y(NO₃)₃ · 6H₂O) as raw materials and ammonium bicarbonate (NH₄HCO₃) and liquor ammonia (NH4OH) as the precipitators. In order to get the powder with favorable dispersibility, polyethylene glycol (PEG, HO(CH₂CH₂O) n H) with different molecular weights and amounts was used as a dispersant agent in the synthesis process and its effects on the YSZ powder was investigated. The scanning electron micrograph (SEM) images showed that the degree of agglomeration and the mean crystal size of YSZ powder varied with the amount and the molecular weight of PEG. The appropriate amount and molecular weight of PEG were given by comparing the dispersibility and crystal size distribution of powders. In the process, one also could find that the promotion of dispersion was insensitive to the molecular weight, and all PEG (400–2000) can exert an ability to reduce the agglomeration. The proper amount of PEG400, PEG600, PEG1000, PEG2000 was 3 wt%, 3 wt%, 2 wt%, 2 wt%, respectively. The transmission electric microscope studies in conjunction with the XRD analyzes verified the low degree of agglomeration and the size of YSZ powder varied between 10~20 nm.

Vancomycin intermediate-Resistant Staphylococcus aureus (VISA) Isolated from a patient who never received Vancomycin treatment

With the abuse of antibiotics, the methicillin-resistant Staphylococcus aureus (MRSA) strain became prevalent. Furthermore, Staphylococcus aureus with a character of vancomycin intermediate-resistance (VISA) has been found globally since the first report in Japan. The main objectives of this study were to report a case of VISA isolated from a Chinese patient who had never undergone Vancomycin treatment, and to determine its molecular character. A total of 9 strains were recovered from a patient during the therapeutic process. Antimicrobial susceptibility testing was performed to determine their antibiotic susceptibility patterns. To detect the VISA strain's molecular epidemiological features, growth and morphological characters, we used multilocus sequence typing, autolysis assay and transmission electric microscope tests. Pulsed-field gel electrophoresis (PFGE) was performed to characterize the heterogeneities of all isolates. One isolate was found to exhibit vancomycin intermediated-resistant with MIC of 8 μg/ml. It was ST239-T030-agr-1, had thickened cell wall, and displayed a slower growth rate and reduced susceptibility to Triton X-100-induced autolysis than other strains. All 9 strains exhibited the same PFGE pattern. This is the first report of VISA found in central China from a patient who had never received vancomycin treatment.

In Operando Observation of (La, Sr)CoO3 Perovskite Oxide Solid/Gas Interface by X-ray Absorption Spectroscopy

1. Introduction Lowering of the cathodic overvoltage is one of the paramount strategies to improve the performance of solid oxide fuel cells (SOFCs). La1-xSrxCoO3-δ (LSC) is considered a potential cathode material for SOFCs since it shows the high electronic and ionic mixed conductivity. The cathodic reaction contains many elementary reaction processes such as gas diffusion, surface reaction, bulk diffusion and ion transfer. The previous studies suggested that the surface reaction is the rate-determining step of LSC electrode reaction [1]. However, the processes occurring at the electrode surface is poorly understood. In this study, we investigate the chemical structure of LSC surface during SOFC operating condition by means of in operandoX-ray absorption spectroscopy, and then surface modification is examined to improve the surface reaction kinetics. Some researchers indicate that LSC is exposed to Sr segregation under SOFC operating condition [2, 3]. Because this reaction is occurred at nanometer scale of the electrode surface, the true phenomena have not been clearly understood. In order to analysis surface chemistry during SOFC operation condition, in operandototal-reflection fluorescence XAS was applied. This method is useful to observe the surface reaction at the nanometer scales[4]. Surface modification of LaSrCoO3- δ (LSC214) on La0.6Sr0.4CoO3- δ (LSC113) is interesting strategy to improve surface reaction [5]. To understand the effect of surface modification, we examined uncoated LSC113 and LSC214 coated LSC113 electrodes with electrochemical impedance spectroscopy, in operandoXAS and fluorescence X-ray analysis (XRF). 2. Experiment Model thin film electrodes were prepared by plasma laser deposition (PLD) method. Substrate was YSZ (110) single crystal. First we deposited Gd0.2Ce0.8O1.9 buffer layer about 5 nm and then La0. 6Sr0. 4CoO3 - d was deposited for about 70 nm thickness. For the surface modification, LaSrCoO3- δwas coated with various thicknesses.We characterized crystal structure by XRD, thickness by a transmission electric microscope, surface roughness by atomic force microscope. Electrochemical impedance spectroscopy was measured range of 1 M-0.1 Hz.For in operandoXAS measurement, homemade cells were used. Counter and reference electrode were porous Pt. We made these 3-electrode cells 5 mm-square as samples for XRF and XAS, and placed into small electric furnace. Co K-edge XAS was measured at BL01B1, SPring-8 in Japan. The fluorescence mode was used and incident X-ray angle was determined as a half of the count value at the critical angle in total reflection measurements. The penetration depth is estimated approximately 5 nm. 3. Results Figure 1 shows Nyquist plots from electrochemical impedance spectroscopy for uncoated LSC113 and LSC214 coated electrodes. The LSC214 coating significantly decreases the electrode resistance. Especially LSC214 coating for 3 nm on LSC113 cathode shows highest reaction kinetics.Figure 2 shows absorption edge energy shift from Co K-edge XAS as a function of applying voltage which is converted to effective oxygen partial pressure [1]. For the uncoated LSC113 electrode, significant energy shift is observed in cathodic condition. Combined with the result of fluorescence spectra, Sr segregation is proofed for the LSC113 electrode. On the other hand, the energy shift is prohibited by LSC 214 coating. As shown in Fig. 2, LSC214 coating suppresses the reduction of Co ion in LSC113 and Sr segregation on surface.Fig.1. Nyquist plot of electrochemical impedance spectroscopy for the uncoated LSC113 and the LSC214 coated LSC113 at 1%-O2atmosphere.Fig.2. Absorption edge shift of XAS as a function of effective partial pressures of oxygen (left). Models of Sr segregation for the uncoated LSC113 and the LSC214 coated LSC113 (right). Reference [1] T. Kawada et. al., J. Electrochem. Soc. 149E252 (2002)[2] E. Crumlin et. al., Energy Environ. Sci., 5, 6081(2011)[3] E. Mutoro et al., J. Phys. Chem. Lett., 3, 40 (2012).[4] D.Takamatsu et a l., Angew. Chem. Int. Ed., 51 ,11597 (2012).[5] E Crumlin et. al., J. Phys. Chem. Lett., 1, 3149 (2010) Acknowledgement This research was partially supported by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Grant-in-Aid for Young Scientists (B) (25810134）

Nano-composite Powder of Tungsten Coated Copper Produced by Thermo-chemistry Co-reduction

Abstract Two kinds of copper oxide with different particle sizes and 1.5 μm tungsten trioxide powder were employed to prepare the high-purity CuWO4 powder. By two stage hydrogen-reduction of the CuWO4 at 360 and 750 °C respectively and continuously, nano-composite powder of tungsten coated copper was synthesized. Micro-morphology, crystallization-components and grain-size of the products were investigated by scanning electron microscope (SEM), X-ray diffract meter (XRD) and transmission electric microscope (TEM) and laser particle size analyzer (LPSA) was also applied to measure the particle-size of CuWO4. The W film thickness of nano-composite powder synthesized by smaller-sized CuWO4 is thinner than that made from bigger-sized CuWO4. The average particle size of nano-composite powder of tungsten coated copper is about 50 nm under the two-stage hydrogen reduction.

Prokaryotic expression and immunogenicity of the chimeric HBcAg containing Aβ(1-15)

To construct a recombinant prokaryoticexpression plasmid pET/ c-Aβ(15)-c, and evaluate the immunogenicity of its encoded fusion protein as expressed in E.coli. The gene fragment HBc88-144 was amplified by PCR and subcloned to pUC19. The synthetic, double-strand Aβ(1-15) gene was inserted downstream of HBc1-71 in pGEMEX/c1-71. After restriction enzyme digestion, c1-71- Aβ(15) was spliced to HBc88-144, yielding the recombinant gene c-Aβ(15)-c; that gene was subcloned into pET-28a(+). The fusion protein (CA15C) expressed in the transformed E.coli BL21 was induced with isopropyl β-D-1-thiogalactopyranoside (IPTG) and analyzed by SDS-PAGE. The virus-like particle (VLP) formed by fusion protein CA15C was observed with transmission electric microscope (TEM). Four Kunming (KM) mice were given intraperitoneal injections of CA15C, and the anti-Aβ antibody elicited was detected by indirect ELISA. The sequence of the recombinant gene was confirmed by restriction enzyme digestion and DNA sequencing. After IPTG induction, the fusion protein was expressed, mainly in the sediment from the bacterial lysate. The expression level was 40% of total protein in the sediment. The CA15C could form VLP. After 5 rounds of immunization, the titer of anti-Aβ antibody in the sera of KM mice reached 1:10000, while the anti-HBc antibody was undetectable. Recombinant c-Aβ(15)-c gene can be expressed in E.coli. The expressed protein can form VLPs and has a strong immunogenicity.

Synthesis and Formation Mechanism of Solid and Hollow Alumina Microspheres at the Water-Oil Interface

NH4Al (OH) 2CO3 (AACH) hollow spheres and solid spheres were successfully synthesized with water in oil in water (W/O/W) emulsion, applying the liquid-to-liquid-phase boundary of the micellar system as a template. During the facile procedure, no high pressure, high temperature, or other complex reaction conditions were required. Transmission electric microscope (TEM) images showed that all the hollow structural products have a good spherical morphology with an average diameter of 1 μm. The as-synthesized spheres had large diameters and thin shells of about 30 nm composed of numerous small nanocrystals. In addition, the AACH product can be calcined into Al2O3 without changing its shape.

Sonodynamically Induced Apoptosis by Protoporphyrin IX on Hepatoma-22 cells In Vitro

The synergistic effect of ultrasound and certain chemicals on cells is known as sonodynamic therapy (SDT). It has been reported that the direct sonochemical and subsequent redox reactions induced by SDT treatment can lead to apoptotic cell death. However, the detailed biologic mechanism about it is not well understood until now. In this study the effect of low-intensity ultrasound on Hepatoma-22 cells (H22) in the presence of the sonosensitizing drug protoporphyrin IX (PpIX) was evaluated at different incubation times after sonication. Trypan blue exclusion was used to detect cell viability. The presence of apoptotic cells was identified by 4'-6-diamidino-2-phenylindole (DAPI) nuclear staining and transmission electric microscope (TEM) observation. An inverted confocal laser scanning microscope was used to detect the release of mitochondrial protein cytochrome c (Cyt c) and the redistribution of Bcl-2 family proteins Bid and Bax. Additionally, the generation of intracellular reactive oxygen species (ROS) and the loss of mitochondria membrane potential (MMP) were quantificationally measured by a fluorescence microplate reader. The results indicated that the synergistic cytotoxicity of PpIX and ultrasound increased in a time-dependent manner and the mitochondria damage may be the main factor for sonodynamically induced apoptosis by PpIX in H22 cells. (E-mail: lshaof@snnu.edu.cn)

Entrapment Efficiency of All-trans Retinoic Acid in Surfactant Vesicles

Spontaneous vesicles of dicetyl dimethyl ammonium chloride (DCDAC) and its mixture with sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) are observed respectively in ethanol-water mixed solvents, which have been demonstrated by negative-staining transmission electric microscope (TEM) and atomic force microscope (AFM). Ethanol can promote the vesicle formation, especially to pure DCDAC surfactant system. The entrapment efficiency of the vesicles to all-trans retinoic acid (ATRA) was measured by the first order derivative spectrophotometry method. The entrapment efficiency of ATRA reaches 22% in 0.5 ethanol volume ratio solution when the concentration of DCDAC is 2.5 × 10−3 mol/L. In the same solvents, the entrapment efficiency could be as high as 62% in 1:9 (molar ratio) DCDAC/AOT mixtures when the total concentration of surfactants is 3.0 × 10−3 mol/L.

Ethambutol induces PKC-dependent cytotoxic and antiproliferative effects on human retinal pigment cells

Ethambutol (EMB)-induced ocular side effects may involve the influence on functions of retinal pigment epithelium (RPE), in addition to EMB-induced optic neuropathy. To address this issue, the molecular and cellular effects of EMB on RPE including growth regulation, morphological responses, phagocytic activity, and the relevant signaling pathways were investigated. EMB (at optimal concentration 8.0 mM) can trigger cell cycle arrest in both RPE50 and ARPE19 cells, accompanied by reduced DNA synthesis. EMB also induced cytoplasmic vacuole formation in both RPE cell lines. Under transmission electric microscope, the phagosomes were replaced by vacuoles and the number of microvilli was reduced in EMB-treated cells. Animal experiments also demonstrated the vacuole formation within RPE of the EMB-treated rats. On the other hand, by in vitro phagocytosis assay using rod outer segment (ROS) as the target, we found EMB suppressed phagocytosis in the cultured RPE, which is consistent with the decreased rhodopsin uptake in the RPE of the EMB-treated rats. Furthermore, inhibitor of protein kinase C but not MAPK, prevented the EMB-induced phenotypical changes. Using a non-radioactive PKC assay, we also demonstrated the PKC activity in both RPE cell lines can be induced by EMB. In conclusion, EMB may exert toxic effects in RPE including suppression of cell growth, formation of cytoplasmic vacuoles and reduction of phagocytic functions via PKC signal pathway.

A Facile Interfacial Reaction Route To Prepare Magnetic Hollow Spheres with Tunable Shell Thickness

Magnetic Fe3O4 hollow spheres were successfully synthesized with a water in oil in water (W/O/W) emulsion. During the facile procedure, no high pressure, high temperature, or other complex reaction conditions were required. Transmission electric microscope (TEM) images showed that all the hollow structural products have a good spherical morphology with an average diameter of 160 nm. The average size and the size distribution were further determined with dynamic light scattering (DLS), which reveals that the hollow nanospheres have a narrow size distribution. The average size from DLS was about 180 nm, which approximated that from TEM data. X-ray diffraction (XRD) demonstrates that the products were all Fe3O4 phase without any impurity. By increasing or decreasing the dosage of precipitate and precipitant sources, we controlled the shell thickness successfully in the tens of nanometers range. The formation mechanism of those hollow magnetic nanospheres was discussed by using the "reverse micelle transport" mechanism.