Search

Sm-doped YBa2Cu3O7–δ samples were prepared by conventional solid state reaction method in air. The studies of X-ray photoemission spectroscopy and X-ray absorption spectroscopy indicate that the extra electrons fill the holes in CuO2 planes, so that the hole carrier concentration decrease under Sm substitution. The X-ray absorption spectroscopy of Cu L-edge and O K-edge demonstrates that the hybridization strength between Cu 3 d and O 2 p decreases with increasing content of Sm, but the hybridization strength between Y 4 d, Ba 5 d, Sm 4 f and O 2 p increases with the increasing of Sm content, while the superconductivity of the Sm-doped YBa2Cu3O7–δ samples is suppressed, i.e., the superconducting transition temperature of the samples was lowered. Thus, our experimental results suggest a close relationship between the superconductivity and orbital hybridization.

Central nervous system damage is an essential clinical feature that occurs in the early or late stages of syphilis infection. The abnormal enhancement of microglial phagocytosis can cause damage to the nervous system. However, the contribution of abnormally enhanced microglial phagocytosis to the pathogenesis of Treponema pallidum subsp. pallidum (T. pallidum) infection remains unknown.In this study, we sought to determine the role of recombinant T. pallidum Tp47 in promoting microglia phagocytosis and its associated mechanisms.Microglial HMC3 cells were used to investigate the effect of the Tp47 on phagocytosis and the roles of autophagy and endoplasmic reticulum stress in Tp47-induced phagocytosis.HMC3 cells exhibited obvious phagocytosis when stimulated with Tp47. The levels of P62 degradation, Beclin1 expression and the LC3II/LC3I ratio were significantly elevated, and the fusion of autophagosomes and lysosomes was promoted in Tp47-stimulated HMC3 cells. Treatment with the autophagy inhibitors 3-MA and Baf A1 inhibited Tp47-induced phagocytosis. Meanwhile, the endoplasmic reticulum stress markers PERK, IRE1α, GRP78, ATF4 and XBP1s were upregulated in Tp47-stimulated HMC3 cells. In addition, we found that TUDCA could inhibit Tp47-induced expression of IRE1α but not PERK or ATF4. 4-PBA inhibited TP47-induced PERK and ATF4 protein expression but did not inhibit IRE1α expression. Attenuation of endoplasmic reticulum stress by administration of TUDCA and 4-PBA abrogated Tp47-mediated autophagy.These results suggested that Tp47 activated autophagy through two key pathways associated with endoplasmic reticulum stress, PERK/ATF4 and IRE1/XBP1, to promote phagocytosis in HMC3 cells. These findings provided a basis for the understanding of the pathophysiology of neurological disorders that occur during the course of syphilis.

1例因腹胀就诊新生儿，发现肠系膜肿物，伴凝血功能异常、血小板减少，超声及CT未能明确该肿瘤性质，腹腔穿刺放腹水，输血治疗效果差，行剖腹探查术，术中见瘤体来源于肠系膜并广泛侵犯血管及小肠肠管，难以切除，病理免疫组化诊断为卡波西型血管内皮瘤。.

Objective To construct a polymerase chain reaction-capillary electrophoresis （PCR-CE） detection method using绿藻目的 利用绿藻法医病理学；法医遗传学；溺水；聚合酶链反应；毛细管电泳；蓝藻；绿藻；

The aim of this study was to explore the effect of circ MTHFD2 on resistance to pemetrexed (MTA) in gastric cancer by regulating the expression of micro ribonucleic acid (miR)-124.Human gastric cancer MGC-803 cells were induced by MTA at an increasing concentration. MGC-803/MTA resistant cell model was successfully established after 5 months. The half-maximal inhibitory concentration (IC50) of MTA on the two kinds of cells was detected via cell counting kit-8 (CCK-8) assay. Differentially expressed circular RNAs (circRNAs) were screened using circRNA microarray analysis. Meanwhile, the target miRNAs of circRNAs were predicted using bioinformatics tool and verified via luciferase reporter assay, respectively. In MGC-803 cells, the effects of overexpression and knockdown of circ MTHFD2 on the expression of miR-124 were detected via quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Finally, the effects of circ MTHFD2 on the protein expressions of FDZ5 and multidrug resistance gene-1 (MDR-1) were detected via Western blotting.MGC-803/MTA resistant cell lines were successfully constructed via persistent drug exposure to MTA at an increasing concentration for 5 months. Compared with parental cells, MGC-803/MTA resistant cells showed significantly enhanced drug resistance. Subsequently, differentially expressed circRNAs were screened using circRNA microarray analysis. A total of 673 circRNAs were screened out based on Fold Change3 and adjusted p-value. The results of qRT-PCR showed that the expression levels of all differentially expressed circRNAs were significantly changed when compared with MGC-803/MTA resistant cells. Compared with MGC-803/MTA resistant cells, the drug resistance of cells increased significantly in circ MTHFD2 overexpression group. However, it markedly decreased in circ MTHFD2 knockdown group. According to the results of bioinformatics and luciferase reporter assay, circ MTHFD2 could target bind to miR-124. In MGC-803/MTA cells, miR-124 could remarkably increase the resistance of MGC-803/MTA cells to MTA. Western blotting results revealed that overexpression of circ MTHFD2 significantly increased the protein expressions of FDZ5 and MDR-1. However, miR-124 mimics reversed the inhibitory effect of circ MTHFD2 on FDZ5 and MDR-1.Circ MTHFD2 directly binds to miR-124 through the molecular sponge effect. This may induce increased protein expression of MDR-1, ultimately enhancing the drug resistance of MGC-803/MTA cells.

To detect the protein level of Decorin in non-small cell lung cancer (NSCLC) patients, and to study the mechanism of Decorin inhibiting invasion and metastasis of non-small cell lung cancer from the perspective of in vitro cells, and provide some theoretical support for the treatment of non-small cell lung cancer.Immunohistochemical staining was used to detect the expression of Decorin protein in 332 cases of stage I-IIIA clinical NSCLC and 70 cases of adjacent tissues. Then, in vitro cell experiments (cell scratch assay and transwell assay) were used to further study the effects of Decorin on migration and invasion of human lung cancer cell line A549; the effect of transforming growth factor-β on the expression of Decorin and Ets-1 protein was verified by Western blotting. The binding sites of Ets-1 and Decorin promoter were analyzed by bioinformatics.Exogenous Decorin inhibited invasion and metastasis of lung adenocarcinoma cells in vitro. Immunohistochemical staining showed that Decorin was lowly expressed in non-small cell lung cancer and Decorin had a certain effect on lung fibroblast activation. Western blotting results showed that TGF-β affects the expression of Decorin and Ets-1. Bioinformatics results showed that Ets-1 and Decorin gene DNA promoter regions have 18 binding sites.Decorin inhibits invasion and metastasis of non-small cell lung cancer through the TGF-β signaling pathway.

Dietary delivery of bacterially expressed double-stranded RNA (dsRNA) has a great potential for management of Leptinotarsa decemlineata. An important first step is to discover possible RNA-interference (RNAi)-target genes effective against larvae, especially the old larvae. In the present paper, five putative Broad-Complex (BrC) cDNAs (Z1-Z4, and Z6) were identified in L. decemlineata. The expression of the five LdBrC isoforms was suppressed by juvenile hormone signaling, whereas the transcription was upregulated by 20-hydroxyecdysone signaling at the fourth (final) instar larval stage. Feeding of bacterially expressed dsBrC (derived from a common fragment of the five LdBrC variants) in the third- and fourth-instar larvae successfully knocked down the target mRNAs. For the fourth-instar LdBrC RNAi hypomorphs, they had a higher larval mortality compared with the controls. Moreover, most dsBrC-fed beetles did not pupate normally. After removal of the apolysed larval cuticle, a miniature adult was found. The adult head, compound eyes, prothorax, mesothorax, metathorax were found on the dorsal view. Distinct adult cuticle pigmentation was seen on the prothorax. The mouthparts, forelegs, midlegs, and hindlegs could be observed on the ventral view of the miniature adults. For the third-instar LdBrC RNAi specimens, around 20% moribund beetles remained as prepupae and finally died. Therefore, LdBrC is among the most attractive candidate genes for RNAi to control the fourth-instar larvae in L. decemlineata.

Many studies have examined the general public’s attitudes towards people with mental illness, but such studies are scarce in China. This study examined the perceptions of the Beijing population regarding their society’s prevalent attitudes towards people with mental illness. A total of 5000 individuals aged 18 or above living in Beijing were selected using a multistage, stratified, cluster and random sampling method. This was followed by a face-to-face interview which used a standardized questionnaire asking about societal attitudes towards individuals with mental illness. 4602 out of 5000 eligible individuals met the inclusion criteria and participated in the interview. 4596 questionnaires were deemed valid and included in the analyses. A large proportion of respondents believed that most individuals within their society held negative attitudes and had a strong desire to distance themselves from people with mental illness. Respondents aged 60 or older, who lived farther to downtown Beijing, or with higher education tended to believe that most individuals have relatively positive and tolerant attitudes towards people with mental illness. Many people in Beijing perceive that most members of their society have negative beliefs towards people with mental illness. Further efforts are needed to determine if these perceptions are accurate and to reduce the stigma that is reinforced by these perceptions.

Two Drosophila melanogaster E-twenty-six domain transcription factor isoforms (E74A and E74B) act differentially at the start of the 20-hydroxyecdysone (20E) signalling cascade to regulate larval-pupal metamorphosis. In the present paper, we identified the two isoforms (LdE74A and LdE74B) in Leptinotarsa decemlineata. During the larval development stage, the mRNA transcript levels of the two LdE74 isoforms were correlated with circulating 20E titres. In vitro midgut culture and in vivo dietary supplementation with 20E revealed that the presence of 20E induced expression peaks of both LdE74A and LdE74B, with similar patterns observed for the two isoforms. Moreover, the mRNA transcript levels of both LdE74A and LdE74B isoforms were significantly downregulated in the L. decemlineata ecdysone receptor RNA interference (RNAi) specimens, but not in the LdE75 RNAi beetles. Ingestion of 20E reduced the larval fresh weights and shortened the larval development period, irrespective of knockdown of LdE74 or not. RNAi of LdE74 did not affect 20E-induced expression of the Ecdysone induced protein 75-hormone receptor 3-fushi tarazu factor 1 (E75-HR3-FTZ-F1) transcriptional cascade. Thus, it seems that LdE74 mediates 20E signalling independent of the E75-HR3-FTZ-F1 transcriptional cascade. Furthermore, silencing of both LdE74 isoforms caused failure of ecdysis. Most of the LdE74 RNAi beetles remained as prepupae. The LdE74 RNAi prepupae exhibited adult character-like forms underneath after removal of the apolysed larval cuticle. Their appendages such as antennae, legs and wings were shorter than those of control larvae. Only a few LdE74 RNAi larvae finally became deformed pupae, with shortened antennae and legs. Therefore, LdE74 is required for larval-pupal metamorphosis and appendage growth in L. decemlineata.

Objective To discuss the application value of diatom examination in lung tissue for the forensic diagnosis of drowning. Methods The experimental animals were divided randomly into drowning, postmortem submergence and dying on land group. Diatoms in lung tissue and drowning fluid were analyzed quantitatively by microwave digestion-vacuum filtration-automated scanning electron microscopy diatom examination method. The ratios of content of diatoms in lung tissue and drowning fluid （肺组织硅藻定量分析在实验动物溺死诊断中的应用.目的 探讨肺组织硅藻检验在法医学溺死诊断中的应用价值。 方法 将实验动物随机分为溺死组、死后入水组和陆地死亡组，采用微波消解-真空抽滤-扫描电镜联用的硅藻检验方法对肺组织和溺液硅藻进行定量分析，记录肺组织与溺液硅藻含量的比值（ratio of content of diatoms in lung tissue and drowning fluid，法医病理学；溺水；硅藻类；动物，实验；兔；猪；肺.

Acanthopanax senticosus fresh leaf was used as the experimental material to produce tea, Eurotium cristatum was used to ferment the Acanthopanax sentieosus tea. The variations of main quality components and enzymatic activity were examined during the fermentation process. The results showed that tea polyphenols, amino acid, and soluble sugar were decreased from 16.36%, 4.33%, 1.96% to 5.42%, 1.34%, 0.88%. The theabrownin was increased from 14.0% to 16.61%, but theaflavins and thearubigins were increased and then decreased during the fermentation process of Acanthopanax sentieosus tea. In addition, cellulase, pectinase and protease had been there as the endogenous enzyme before generating microorganisms, while polyphenol oxidase were exogenous enzymes. The main quality components and enzymatic activity were changed obviously as the time was prolonged. The quality of Acanthopanax sentieosus tea was improved effectively, which provided theoretical basis for the production and application of fermented-tea of Acanthopanax senticosus.

The AML1-ETO fusion protein (AE) resulting from the t(8;21) translocation is highly related to the pathogenesis and development of leukemia. microRNA-9 (miR-9) acts as a tumor suppressor gene in AE-positive acute myeloid leukemia (AML). Silent mating type information regulation 2 homolog-1 (SIRT1) is overexpressed in most cancer cells by increasing proliferation as a tumorigenic gene. The present study was performed to investigate the underlying interaction between miR-9 and SIRT1 in AE-positive AML.Expression of miR-9 and SIRT1 in AE-positive AML patients, healthy donors and AML cell lines were detected by qPCR. Relevance between miR-9 and SIRT1 was assessed by plasmid transfection, Western blot and correlation analysis. Luciferase assay was used to confirm the target gene of miR-9. Knockdown of SIRT1 in different cell lines was achieved by shRNA transfection and CCK-8 assay was used to investigate the effects on cell proliferation.The miR-9 expression was lower in AE-positive cell lines compared to that in other AE-negative AML cell lines, while expression of SIRT1 was higher in AE-positive cell lines. Expression of miR-9 was also downregulated in adult primary t(8;21) AML patients compared to healthy donors. The over-expression of miR-9 decreased luciferase activity of wild-type SIRT1, which was recovered after transfection with mutant SIRT1. The miR-9 directly targets SIRT1 by binding to its 3'-untranslated region and reducing its protein levels. Importantly, miR-9 and SIRT1 mRNA levels were inversely correlated in AE-positive AML cell lines and t(8;21) AML primary leukemia cells. Knockdown of SIRT1 levels using shSIRT1 inhibited cell proliferation in AE-positive AML cell lines.SIRT1 is the target gene of miR-9 and the signaling pathway connecting miR-9 and SIRT1 is a therapeutic target for t(8;21) AML.

The bodies found in water are one of the most common types in forensic practice. The discovery site of the body is often not the drowning site. However, the determination of drowning site is vital for the identification of victim. Inorganic particles and planktons, such as granular impurities, diatoms and bacteria, are valuable markers for the diagnosis of drowning. By comparing the granular impurities and planktons in tissues and suspicious drowning mediums, the drowning site can be concluded based on their similarity of types and distribution, which has practical applied value. In this paper, the research progress on determination of drowning site is summarized to provide reference for the peers.

The aim of this study was to retrospectively evaluate the technical success rates and clinical effectiveness of fluoroscopically guided nose tube drainage of mediastinal abscesses and a nasojejunum feeding tube in post-operative gastro-oesophageal anastomotic leakage (GEAL).From January 2006 to June 2011, 18 cases of post-operative GEAL with mediastinal abscesses after oesophagectomy with intrathoracic oesophagogastric anastomotic procedures for oesophageal and cardiac carcinoma were treated by insertion of a nose drainage tube and nasojejunum feeding tube under fluoroscopic guidance. We evaluated the feasibility of two-tube insertion to facilitate leakage site closure and complete resolution of the abscess, and the patients' nutritional benefit was also evaluated by checking the serum albumin level between pre- and post-enteral feeding via the feeding tube.The two tubes were placed successfully under fluoroscopic guidance in 18 patients (100%). The procedure time for two-tube insertion ranged from 20 to 40 min (mean 30 min). 17 patients (94%) achieved leakage site closure after two-tube insertion and had a good tolerance of two tubes in the nasal cavity. The serum albumin level was significant, increased from pre-enteral feeding (2.49 ± 0.42 g dl(-1)) to the post-enteral feeding (3.58 ± 0.47 g dl(-1)) via the feeding tube (p0.001). The duration of follow-up ranged from 1 to 49 months (mean 19 months).The insertion of nose tube drainage and a nasojejunum feeding tube under fluoroscopic guidance is safe, and it provides effective relief from mediastinal abscesses in GEAL after oesophagectomy. Moreover, our findings indicate that two-tube insertion may be used as a selective procedure to treat mediastinal abscesses in post-operative GEAL. Advances in knowledge Directive drainage of mediastinal abscesses in post-operative GEAL may be an effective treatment.

Hyaluronic acid (HA) hydrogel was modified with poly(L-lysine) (PLL) and Nogo-66 Receptor antibody (antiNgR) to enhance the repair of central nervous system (CNS) injuries. The immobilization of PLL was characterized by X-ray photoelectron spectroscopy (XPS) and the immobilization of antiNgR was studied by immunofluorescence. The cytocompatibility of this modified hydrogel was analyzed by culturing primary hippocampal neurons. The quantity and morphology of the neurons were influenced by different modifications; the primary hippocampal neurons cultured with modified HA hydrogel exhibited multipolar and bipolar morphology were compared with unmodified hydrogel cultures. The number of neurons obtained by culturing with HA hydrogel modified with both PLL and antiNgR was almost twice the number of neurons cultured with HA modified with only PLL or antiNgR. This phenomenon was attributed to the collaborative effect of PLL and antiNgR on the neurons. The characteristics of this new hydrogel system, including pore structure, water absorption, hydrolysis degradation did not change much when compared with the hydrogel modified with PLL or antiNgR, respectively. It is expected that this modified HA hydrogel has potential as a CNS tissue engineering material.

EXO-200 is a single phase liquid xenon detector designed to search for neutrinoless ββ decay of ^(136)Xe to the ground state of ^(136)Ba. We report here on a search for the two-neutrino ββ decay of 136Xe to the first 0+ excited state, 0^+_1, of ^(136)Ba based on a 100 kg yr exposure of ^(136)Xe. Using a specialized analysis employing a machine learning algorithm, we obtain a 90% CL half-life sensitivity of 1.7 × 10^(24) yr. We find no statistically significant evidence for the 2νββ decay to the excited state resulting in a lower limit of T^(2ν)_(1/2)(0^+ → 0^+_1) > 6.9 ×10^(23) yr at 90% CL. This observed limit is consistent with the estimated half-life of 2.5 × 10^(25) yr.

In this study, we investigated the association between the interleukin (IL)-10 -592C/A, -819C/T, and -1082G/A genetic variations and susceptibility to diabetic nephropathy in a Chinese population. The IL-10 -592C/A, -819C/T, and -1082G/A polymorphisms were genotyped in diabetic nephropathy patient and control samples by polymerase chain reaction-restriction fragment length polymorphism. The results were then statistically analyzed using SPSS 17.0. The results of the χ(2) test revealed a significant difference in the frequencies of the GG, GA, and AA genotypes of IL-10 -1082G/A between patients with diabetic nephropathy and control subjects (χ(2) = 10.03, P = 0.007). Unconditional logistic regression analysis revealed that the AA genotype of IL-10 -1082G/A significantly increased the susceptibility to diabetic nephropathy [adjusted odds ratio (OR) = 2.52, 95% confidence interval (CI) = 1.31-4.82] compared to the wild-type genotype. Moreover, the A allele of this polymorphism was associated with an increased risk of diabetic nephropathy compared to the G allele (adjusted OR = 1.51, 95%CI = 1.15-1.99). However, the IL-10 -819T/C and -592A/C genetic polymorphisms did not increase the risk of diabetic nephropathy. In conclusion, the IL-10 -1082G/A polymorphism was found to be correlated with the development of diabetic nephropathy.

In this paper, hyaluronic acid hydrogels with open porous structure have been developed for scaffold of brain tissue engineering. A short peptide sequence of arginine–glycine–aspartic acid (RGD) was immobilized on the backbone of the hydrogels. Both unmodified hydrogels and those modified with RGD were implanted into the defects of cortex in rats and evaluated for their ability to improve tissue reconstruction. After 6 and 12 weeks, sections of brains were processed for DAB and Glees staining. They were also labeled with GFAP and ED1 antibodies, and observed under the SEM for ultrastructral examination. After implanting into the lesion of cortex, the porous hydrogels functioned as a scaffold to support cells infiltration and angiogenesis, simultaneously inhibitting the formation of glial scar. In addition, HA hydrogels modified with RGD were able to promote neurites extension. Our experiments showed that the hyaluronic acid-RGD hydrogel provided a structural, three-dimensional continuity across the defect and favoured reorganization of local wound-repair cells, angiogenesis and axonal growth into the hydrogel scaffold, while there was little evidence of axons regeneration in unmodified hydrogel.

The rat hippocampal cells were selected as model to study the interaction between the neural cells and silicon substrates using atomic force microscopy (AFM). The hippocampal cells show tight adherence on silicon wafers with nano-scale surface topograph. The lateral friction force investigated by AFM shows significant increase on the boundary around the cellular body. It is considered to relate to the cytoskeleton and cellular secretions. After ultrasonic wash in ethanol and acetone step by step, the surface of silicon wafers was observed by AFM sequentially. We have found that the culture leftovers form tight porous networks and a monolayer on the silicon wafers. It is concluded that the leftovers overspreading on the silicon substrates are the base of cell adherence on such smooth inert surfaces.

Electron holography was applied to study the microstructure evolution of magnetic tunnelling junctions (MTJs) CoFe/AlO(x)/Co annealed at different temperatures. A mean inner potential barrier was observed in the as-deposited MTJ sample, while it was changed to a potential well after a 200 degrees C or a 400 degrees C annealing. It is suggested that the oxygen atoms were redistributed during the annealing, which left metallic atoms acting as acceptors to confine the electrons, leading to the decrease of the potential of the AlO(x) barrier layer. The results suggest that the electron holography may be a useful tool for the study of the microstructure of amorphous materials.

The sensitizing effects of polyfunctional poly(ester acrylate) on the radiation crosslinking of polycaprolactone (PCL) were studied. The influences of the use of the polyfunctional material, the number of functional groups, and the radiation dose on the radiation crosslinking, dynamic mechanical properties, and shape-memory behaviors of PCL, respectively, were investigated. The radiation crosslinking of PCL, under the conditions in which the polyfunctional material was applied, did not follow the classic Charlesby–Pinner equation but instead followed the Chen–Liu–Tang relation. The efficiency of the radiation crosslinking of PCL was distinctly improved with the polyfunctional material. The greater the usage and functional group number were, the greater gel content and the more distinctive the radiation-crosslinking effects were. This also indicated that the polyfunctional material directly participated in the crosslinking reaction. Dynamic mechanical analysis indicated that enhanced radiation crosslinking better raised the heat deformation temperature of PCL and presented a higher and wider rubbery-state plateau; it also produced greater strength at temperatures higher than the melting temperature and provided greater force for recovering the deformation than pure PCL. The shape-memory results revealed that sensitizing crosslinked PCL presented 100% recoverable deformation and a quicker recovery rate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 634–639, 2005

A poly[N-(2-hydroxypropyl) methacrylamide] (PHPMA) hydrogel immobilized with the neurite-promoting peptide sequence of xIKVAVx was synthesized and its structure was characterized. The PHPMA-IKVAV hydrogel displayed an interconnected porous structure. The ability of the hydrogel to support axonal outgrowth in the injured adult rats cerebrum cavity and to promote tissue regeneration was evaluated. After implantation for 4, 6, 12 and 18 weeks, the brain sections were processed for histological staining. The observations of the sections showed that the polymer hydrogel provided a structural, three-dimensional continuity across the defect and favoured reorganization of local wound-repair cells, angiogenesis and axonal growth into the hydrogel scaffold. Compared with the unmodified PHPMA hydrogel, the PHPMA-IKVAV hydrogel displayed greater ability to repair tissue defects in the cerebrum nervous system.

Poly(ϵ-caprolactone) (PCL) with different molecular weight were crosslinked by γ-radiation. The radiation crosslinking features were analyzed by Soxhlet extraction with toluene and the Charlesby–Pinner equation. The crosslinking degree is relative to molecular weight and radiation dose; the relation between sol fraction and dose follows the Charlesby–Pinner equation. All the samples were crystalline at room temperature, and the radiation crosslinking had a little effect on the crystallinity and the melting behavior of PCL. The shape-memory results indicated that only those specimens that had a sufficiently high crosslinking degree (gel content is higher than about 10%) were able to show the typical shape-memory effect, a large recoverable strain, and a high final recovery rate. The response temperature of the recovery effect (about 55°C) was related to the melting point of the samples. The PCL shape-memory polymer was characterized by its low recovery temperature and large recovery deformation that resulted from the aliphatic polyester chain of PCL. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1589–1595, 2003

The plateaus in laser-assisted recombination and high-order harmonic generation are investigated in the frequency domain. It is found that the probability amplitude of finding an electron with a given energy is given by a generalized Bessel function, which can be represented as a coherent superposition of contributions from a few electronic quantum trajectories. This concept is illustrated by comparing the spectral density of the electron with the laser-assisted recombination spectrum. On the other hand, the plateau of high-order harmonic generation reflects the spectral density of the electron at the location of the nucleus after above-threshold ionization.

The microstructure of domains and boundaries in a bulk orthorhombic La2/3Ca1/3MnO3 material is analysed by applying symmetry group theory. Group theory predicts that the 120° and 90° orientation domains occur in bulk La1− x Ca x MnO3 (LCMO) when the cubic LCMO transforms into the orthorhombic LCMO by means of a structural phase transition. The orientation domains are observed and characterized by means of electron diffraction and high-resolution electron microscopy. Antiphase boundaries due to the loss of translation operations have displacement vectors of 1/2[010]o, 1/2[101]o and 1/2[111]0, according to the group theory. Diffraction contrast technique reveals that the displacive vector of most antiphase boundaries is 1/2[111]o, which is also confirmed by means of high-resolution electron microscopy.

Electron holography (EH) in a field emission gun transmission electron microscope has been used to profile the inner potential V 0 across CoFe/AlO x /Co magnetic tunneling junctions (MTJs). The spatial dimension of the AlO x barrier layer can be accurately determined from the phase profile at the tunneling junctions. The EH results show unambiguously that the potential jump across the CoFe/AlO x interface is smaller than that across the Co/AlO x interface, which results in asymmetrical barriers in the MTJs. The inner potential difference and the asymmetrical barrier were discussed based on the different oxidation statuses between Co/AlO x and CoFe/AlO x interfaces.

The adherence and viability of central neural cells (substantia nigra) on a thin layer of SiO 2 on Si wafers with different surface roughness were investigated. Variable roughness of the Si wafer surface was achieved by etching. The nano-scale surface topography was evaluated by atomic force microscopy. The adherence and subsequent viability of the cells on the wafer were examined by scanning electron microscopy (SEM) and fluorescence immunostaining of tyrosine hydroxylase (TH). It is found that the surface roughness significantly affected cell adhesion and viability. Cells survived for over 5 days with normal morphology and expressed neuronal TH when grown on surfaces with an average roughness (Ra) ranging from 20 to 50 nm. However, cell adherence was adversely affected when surfaces with Ra less than 10 nm and rough surfaces with Ra above 70 nm were used as the substrate. Such a simple preparation procedure may provide a suitable interface surface for silicon-based devices and neurones or other living tissues.

The adherence and subsequent viability of central neural cells (substantia nigra) on silicon wafers with different surface roughness conditions were investigated. Various roughness conditions of the silicon wafer were achieved by etching at different times. The topography was evaluated by AFM. Primary neurons were obtained from Wistar rats. The adherence and subsequent viability of the cells on the wafer were examined by scanning electronic microscopy and fluorescence immunostaining of tyrosine hydroxylase. It is found that the surface roughness affects significantly cell adhesion and viability. Cells can survive for over 5 days on the surface with average roughness in the range 20–70 nm. Such a treatment may provide a new method to make a mild interface of silicon-based electronic devices and neurons as well as other living tissues.

We have determined the dependence of the exchange coupling on both the thickness of the antiferromagnetic (AF) layer (tAF) and that of the ferromagnetic (FM) layer (tFM) in a Fe50Mn50/permalloy bilayer, where the thickness of the FeMn layer varies from 0.5 to 32 nm with a fixed permalloy layer of 30 nm, and that of the permalloy layer varies from 3.5 to 45 nm with the uniform FeMn layer fixed at 10 nm. For tAF>3 nm, the exchange field Hex varies as 1/tAF0.3 at both 80 and 300 K, whereas the coercivity does not vary with tAF. The dependence of Hex on tFM displays a behaviour varying as 1/tFM0.9, and HC a behaviour varying as 1/tFM1.7 which is close to the theoretical prediction based on a random field at the interface of a FM/AF bilayer.

A series of NiO(110 A)/FeNi(tF A)/Cu(24 A)/FeNi(tF A) spin-valve-structure samples were fabricated using ion beam sputtering. The exchange bias HE of the pinned FeNi layer increases as the FeNi thickness tF decreases. For tF

A series of (Co0.35Fe0.65)x(Al2O3)(1-x) (volume fraction) nanogranular films was fabricated using magnetron sputtering. The Hall effect of the films increases as the volume fraction of Co0.35Fe0.65 decreases near percolation. The saturated Hall resistivity of (Co0.35Fe0.65)0.43(Al2O3)0.57 is about 5.5 µΩ cm at room temperature. This suggests that the giant Hall effect (GHE) may be due to the percolation phenomenon. The correlation of the Hall effect and tunnelling magnetoresistance (TMR) with the alloy volume fraction is discussed.

An alloy of the nominal composition of Ti-62.5at.% Al was annealed at 1000 degrees C. Transmission electron microscopy (TEM) was performed to study the microstructure. Two types of crystallographic orientation relationships (ORs) between Ti3Al5 and TiAl2L (L for long period) were found. They respectively correspond to different phase interfaces. Most of the observed interfaces correspond to an OR of aTi(3)Al(5) // aTiAl(2)(L), cTi(3)Al(5) // cTiAl(2)(L). Such a type of (001) interfaces contains dislocation networks with orthogonal Burgers vectors along [110] and [110]. (101) interfaces containing ledges can occasionally be observed. The corresponding OR slightly deviates from bTi(3)Al(5) // bTiAl(2)(L), aTi(3)Al(5) // cTiAl(2)(L). The different interfaces are accounted for misfit between Ti3Al5 and TiAl2L, and might result from different phase transition procedures.

An 8-wk experiment was conducted to evaluate the effect of replacing fish meal (FM) with soy protein isolate (SPI) on the growth, digestive enzyme activity and serum biochemical parameters of juvenile Amur sturgeon (Acipenser schrenckii). SPI was used to replace 0, 25, 50, 62.5, 75, 87.5, 100% of dietary FM and 100% replacement supplemented crystalline amino acid. Healthy sturgeon with an average initial weight of 26.38±0.24 g were randomly assigned to 24 aquaria (8 treatments with triplicates each) at an initial stocking density of 11 fish per aquarium and cultured for 8 wks. The results showed that 75.00% or more substitution resulted in a poor weight gain rate, feed conversion ratio and survival rate compared to that of fish fed the control diet (p

Microstructures of the specular spin valve with two nano-oxide layers (NOL1 and NOL2) have been studied at the atomic level. When the NOLs are incorporated in a bottom-pinned spin valve, a significant enhancement in magnetoresistance ratio with greatly decreased sense-layer thickness is achieved. Cross-sectional high-resolution electron microscopy (HREM) studies show that the NOL1 introduced from oxidation of the original bottom-pinned CoFe layer is actually a mixture of oxides and ferromagnetic metals. No CoFe oxides but Ta2O5 is found over the oxidation-treated CoFe sense layer by HREM and x-ray photoelectron spectroscopy study. The Ta2O5 layer acting as the NOL2 can be interpreted as being formed through a solid-state oxidation reaction between the oxidized CoFe sense layer and the Ta capping layers.

The objective of the study was to determine the effects of a hyaluronic-acid-based (HA-based) hydrogel implant, carrying a polyclonal antibody to the Nogo-66 receptor (NgR), on adult rats that underwent middle cerebral artery occlusion (MCAO). Behavioral tests of a forelimb-reaching task suggested that the disabled function of the impaired forelimb in this stroke model was ameliorated by the implant to a certain extent. These behavioral findings were correlated with immunohistochemical results of investigating the distribution of NgR antibody, neurofilaments (NF) and neuron-specific class III beta-tubulin (TuJ1) in the brain sections. The porous hydrogel functioned as a scaffold to deliver the NgR antibody, support cell migration and development. In addition, it was found NF-positive and TuJ1-positive expressions were distributed in the implanted hydrogel. Collectively, the results demonstrate the promise of the HA hydrogel as a scaffold material and the delivery vehicle of the NgR antibody for the repair of defects and the support of neural regeneration in the brain.

The selection of appropriate surface materials that promote cellular adhesion and growth is an important consideration when designing a simplified neuronal network in vitro. In the past, extracellular matrix proteins such as laminin (LN) or positively charged substances such as poly-l-lysine (PLL) have been used. In this study, we examined the ability of another positively charged polymer, polyethyleneimine (PEI), to promote neuronal adhesion, growth and the formation of a functional neuronal network in vitro. PEI, PLL and LN were used to produce grid-shape patterns on glass coverslips by micro-contact printing. Post-mitotic neurons from the rat fetal hippocampus were cultured on the different polymers and the viability and morphology of these neurons under serum-free culture conditions were observed using fluorescent microscopy and atomic force microscopy (AFM). We show that neurons cultured on the PEI- and PLL-coated surfaces adhered to and extended neurites along the grid-shape patterns, whereas neurons cultured on the LN-coated coverslips clustered into clumps of cells. In addition, we found that the neurons on the PEI and PLL-coated grids survived for more than 2 weeks in serum-free conditions, whereas most neurons cultured on the LN-coated grids died after 1 week. Using AFM, we observed some neurosynapse-like structures near the neuronal soma on PEI-coated coverslips. These findings indicate that PEI is a suitable surface for establishing a functional neuronal network in vitro.

The using of layer-by-layer assembly polyelectrolyte (PE) films has been suggested as a new versatile technique for surface modification aimed at tissue engineering and cell-based chips. In this study, we investigated the surface morphology of the hyaluronic acid (HA)-based PE films deposited on the amino-functionalized glass slides using atomic force microscopy. These thin films (bilayer number

Primary neuronal cultures on substrates patterned with extracellular matrix proteins such as laminin have yielded much information regarding the physiological characteristics of neuronal cells in vitro. Surface charge also influences neuronal adherence, and a positive charge can have stimulatory effects. The attraction between laminin patterns and polycation films are of interest in the study of neuronal adhesion. We cultured primary hippocampal neurons on poly(ethylenimine) (PEI) films with laminin grids and evaluated their viability and morphology by means of fluorescent microscopy after 5-7 days. The results showed that the neurons did not form networks on the laminin grids. It is inferred that the PEI films were more favourable for neuronal adhesion than the laminin grid.

The primary cortical cells were selected as a model to study the adherence and neural network development on chemically roughened silicon substrates without any coatings using confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM). The silicon substrates have a nano-range roughness (RMS) achieved by chemical etching using hydrofluoric (HF) acid. After 7 days of culturing, the neurons were observed to connect together and form dense neural networks. Furthermore, AFM results revealed that some porous structures at a few micrometer range existed between the neuron cells and the silicon substrates. It is suggested that the porous structures are made of extracellular matrix (ECM) components and play an important role in the neuronal adhesion and neurite outgrowth on the inert silicon wafers.

The hyaluronic acid (HA) hydrogels modified with laminin were used for implantation in rat brain in present study, in order to investigate its effects in reparation of injury in the CNS. Cross-linked HA hydrogels were synthesized and their characteristics were analyzed. Laminin, an extracellular matrix protein, which participates in neuronal development and survival, was immobilized on the backbone of the hydrogels. Hydrogels unmodified and modified with laminin were implanted into cortical defects mechanically created in rats and their ability to improve tissue reconstruction was then evaluated. After 6 and 12 weeks of implantation, sections of brains were processed with Nissl and Glees staining for revealing neural cell bodies and fibers, with DAB histochemistry for detecting the blood vessels, as well as with immunocytochemistry for recognizing GFAP. The sections were also taken to SEM and TEM for ultrastructral examination. The results showed that the HA hydrogels synthesized had mechanical properties and rheological behavior similar to the brain tissue. After being implanted into the lesion of the cortex, the porous hydrogels created a scaffold, which could support cell infiltration and angiogenesis, and simultaneously inhibit the formation of glial scar. In addition, HA hydrogels modified with laminin could promote neurite extension. It seems possible that the tissue engineering technique may pave the way to repair injury in the CNS as suggested by the results in present study.