Atomic-scale probing of heterointerface phonon bridges in nitride semiconductor.

Interface phonon modes that are generated by several atomic layers at the heterointerface play a major role in the interface thermal conductance for nanoscale high-power devices such as nitride-based high-electron-mobility transistors and light-emitting diodes. Here we measure the local phonon spectra across AlN/Si and AlN/Al interfaces using atomically resolved vibrational electron energy-loss spectroscopy in a scanning transmission electron microscope. At the AlN/Si interface, we observe various interface phonon modes, of which the extended and localized modes act as bridges to connect the bulk AlN modes and bulk Si modes and are expected to boost the phonon transport, thus substantially contributing to interface thermal conductance. In comparison, no such phonon bridge is observed at the AlN/Al interface, for which partially extended modes dominate the interface thermal conductivity. This work provides valuable insights into understanding the interfacial thermal transport in nitride semiconductors and useful guidance for thermal management via interface engineering.

Mountain-water-forest-farmland-lake-grassland-sandland holistic protection and restoration engineering and landscape ecology.

Theoretical researches and practices on the life community of mountain-water-forest-farmland-lake-grassland-sandland mosaic and its protection and restoration have been gradually developed in China, which demands the support of a systematic disciplinary theory. Landscape ecology, as an interdisciplinary science of geography and ecology, can meet such demand thanks to its macroscopic spatial theory and technical system. Here, landscape ecology is taken as the supporting discipline of holistic protection and restoration for mountain-water-forest-farmland-lake-grassland-sandland mosaic. Firstly, we clarified that life community of mountain-water-forest-farmland-lake-grassland-sandland is a heterogeneously mosaic landscape, which bears all the characteristics of landscape and thus follows the principles of landscape ecology. Secondly, we expounded how the basic principles of landscape-ecological construction could be applied to the planning and evaluation of holistic protection and restoration for mountain-water-forest-farmland-lake-grassland-sandland mosaic. Finally, we summarized the new trend of landscape-ecological construction research, listed the theoretical and practical problems to be solved, and discussed how the projects of holistic protection and restoration for the mountain-water-forest-farmland-lake-grassland-sandland mosaic can provide a variety of practices for seeking the solutions. The combination of landscape ecology and practical restoration projects would generate effective solutions to realize sustainable development in terms of ecology, economy, and society in China and even the whole world.

Human anti-EGFL7 recombinant full-length antibodies selected from a mammalian cell-based antibody display library.

Epidermal growth factor-like domain 7 (EGFL7) has been implicated in promoting solid tumor growth and metastasis via stimulating tumor-associated angiogenesis. The advent of antibody display technology (phage, bacteria, and yeast) led to an enormous revival in the use of antibodies as diagnostic and therapeutic tools for fighting cancer. However, problems with protein folding, posttranslational modification, and codon usage still limit the number of improved antibodies that can be obtained. We describe here the isolation of an EGFL7-specific antibody from a mammalian cell-based full-length antibody display library generated from peripheral blood mononuclear cells of patients with hepatocellular carcinoma. Using a novel vector, contained glycosylphosphatidylinositol anchor and restriction enzyme sites NheI and ClaI, antibody libraries are displayed as whole IgG molecules on the cell surface and screened for specific antigen binding by a combination of magnetic beads and measured by cell ELISA. Anti-EGFL7 antibody was successfully isolated from the library. The mammalian cell-based full-length antibody display library is a great potential application for rapid identification and cloning of human mAbs of targeting hepatocellular carcinoma.

Construction and development of a mammalian cell-based full-length antibody display library for targeting hepatocellular carcinoma.

We present a detailed method for constructing a mammalian cell-based full-length antibody display library for targeting hepatocellular carcinoma. Two novel mammalian library vectors pcDNA3-CHm and pcDNA3-CLm were constructed that contained restriction enzyme sites NheI, ClaI and antibody constant domain. Mammalian expression vector pcDNA3-CHm contains IgG heavy-chain (HC) constant region and glycosylphosphatidylinositol anchor (GPI) that could be anchored full-length antibodies on the surface of mammalian cells. GOLPH2 prokaryotic expression vector was carried out in Escherichia coli and purified by immobilized metal affinity chromatography. Variable domain of heavy-chain and variable domain of light-chain genes were respectively inserted into the vector pcDNA3-CHm and pcDNA3-CLm by ligation, and antibody libraries are displayed as whole IgG molecules on the cell surface by co-transfecting this HC-GPI with a light chain. By screening the cell library using magnetic beads and cell ELISA, the cell clone that displayed GOLPH2-specific antibodies on cell surfaces was identified. The mammalian cell-based antibody display library is a great potential application for displaying full-length functional antibodies of targeting hepatocellular carcinoma on the surface of mammalian cells. Anti-GOLPH2 display antibody was successfully isolated from the library.

Spaceflight alters the gene expression profile of cervical cancer cells.

Our previous study revealed that spaceflight induced biological changes in human cervical carcinoma Caski cells. Here, we report that 48A9 cells, which were subcloned from Caski cells, experienced significant growth suppression and exhibited low tumorigenic ability after spaceflight. To further understand the potential mechanism at the transcriptional level, we compared gene expression between 48A9 cells and ground control Caski cells with suppression subtractive hybridization (SSH) and reverse Northern blotting methods, and analyzed the relative gene network and molecular functions with the Ingenuity Pathways Analysis (IPA) program. We found 5 genes, SUB1, SGEF, MALAT-1, MYL6, and MT-CO2, to be up-regulated and identified 3 new cDNAs, termed B4, B5, and C4, in 48A9 cells. In addition, we also identified the two most significant gene networks to indicate the function of these genes using the IPA program. To our knowledge, our results show for the first time that spaceflight can reduce the growth of tumor cells, and we also provide a new model for oncogenesis study.

Autoantibodies as potential biomarkers for nasopharyngeal carcinoma.

Autoantibody signatures, as new biomarkers, may improve the early detection of nasopharyngeal carcinoma (NPC). We constructed a T7 phage cDNA library from mixed NPC tissues, and we isolated 31 tumor-associated proteins using biopan enrichment techniques with sera from NPC patients and from healthy population. DNA sequence analysis showed that among 31 phage-displayed proteins, 22 have sequence identity with known or putative tumor-associated proteins. The results of immunochemical reactivity of patients' sera with phage-expressed proteins showed enrichment in the number of immunogenic phage clones in the biopanning process and also confirmed that antibodies were present in the sera of patients but not in the sera of healthy donors. The autoantibody against phage-expressed protein MAGE, HSP70, Fibronectin, and CD44 measured by ELISA had greater predictive value than that against EBNA-1, respectively. The antibody levels against MAGE in sera positively correlated with the clinical stages of NPC, and the antibody levels against other three proteins partly correlated with the clinical stages of NPC. Our studies suggested that the autoantibodies against tumor-associated antigens in the sera of NPC patients could be used as a screening test for NPC. Studies of the corresponding proteins may have significances in tumor biology, novel drug development, and immunotherapy.

Gamma-aminobutyric acid promotes human hepatocellular carcinoma growth through overexpressed gamma-aminobutyric acid A receptor alpha 3 subunit.

AIM: To investigate the expression pattern of gamma-aminobutyric acid A (GABAA) receptors in hepatocellular carcinoma (HCC) and indicate the relationship among gamma-aminobutyric acid (GABA), gamma-aminobutyric acid A receptor alpha3 subunit (GABRA3) and HCC. METHODS: HCC cell line Chang, HepG2, normal liver cell line L-02 and 8 samples of HCC tissues and paired non-cancerous tissues were analyzed with semiquantitative polymerase chain reaction (PCR) for the expression of GABAA receptors. HepG2 cells were treated with gamma-aminobutyric acid (GABA) at serial concentrations (0, 1, 10, 20, 40 and 60 micromol/L), and their proliferating abilities were analyzed with the 3-(4, 5-methylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, cell doubling time test, colon formation assay, cell cycle analysis and tumor planted in nude mice. Small interfering RNA was used for knocking down the endogenous GABRA3 in HepG2. Proliferating abilities of these cells treated with or without GABA were analyzed. RESULTS: We identified the overexpression of GABRA3 in HCC cells. Knockdown of endogenous GABRA3 expression in HepG2 attenuated HCC cell growth, suggesting its role in HCC cell viability. We determined the in vitro and in vivo effect of GABA in the proliferation of GABRA3-positive cell lines, and found that GABA increased HCC growth in a dose-dependent manner. Notably, the addition of GABA into the cell culture medium promoted the proliferation of GABRA3-expressing HepG2 cells, but not GABRA3-knockdown HepG2 cells. This means that GABA stimulates HepG2 cell growth through GABRA3. CONCLUSION: GABA and GABRA3 play important roles in HCC development and progression and can be a promising molecular target for the development of new diagnostic and therapeutic strategies for HCC.

[Detection of autoantibodies in the sera of nasopharyngeal carcinoma patients].

OBJECTIVE: To investigate whether there are autoantibodies to nasopharyngeal carcinoma (NPC) in the sera of patients and to find new NPC biomarkers. METHODS: Cell plate of Epstein Barr virus negative NPC cell line CNE1 was prepared, and difference between 32 NPC patient sera and 54 normal sera was analyzed by ELISA. We extracted the total protein of CNE1, and analyzed whether there were specific proteins to react with NPC sera by Western blot. RESULTS: The average absorbance values of serum antibody in NPC patients (0.904+/-0.032) were significantly higher than those of normal serum antibody absorbance values (0.736+/-0.028) (P< 0.01). The analysis with Western blot showed there were positive bands,and some of these were unanimous bands, but the intensity increased, and some of these were new bands compared with the normal sera. These positive bands may be NPC tumor-associated antigens or NPC tumor-specific antigens. CONCLUSION: Autoantibodies that react with NPC exist in the sera of NPC patients, but they do not react with Epstein-Barr virus. It provides the basis to seek the tumor biomarkers in NPC sera.

[Landscape pattern change and simulation in the SanJiang Plain based on the CLUE-S model.] / 基于CLUE-Sæ¨¡åž‹çš„ä¸‰æ±Ÿå¹³åŽŸæ™¯è§‚æ ¼å±€å˜åŒ–åŠæ¨¡æ‹Ÿ.

The SanJiang Plain is one of the most concentrated and contiGuous area of marshes, which plays an irreplaceable role in maintaining regional ecological security. Based on the 3S technology, we examined the changes in land use and landscape pattern of the SanJiang Plain from 1980 to 2010. The results showed that marshland area lost 7135 km2, with a loss rate of 59.1%. The paddy area increased 18010 km2, with a growth rate of 610.1%. The results of landscape indices analysis showed that the number of patches increased, the landscape fragmentation became stronger, the landscape heterogeneity increased, and the different landscape types became homogenized. The CLUE-S model was validated based on the five different periods of land use maps during 1980-2010. The Kappa index between the simulation and actual measurement at the time scale of 30 years was 0.71, indicating that the model was suitable for 30 years simulation in the study area. The future wetland changes in the SanJiang Plain from 2010 to 2030 was simulated with validated CLUE-S models, including historical development scenario, planning scenario, and ecological restoration scenario. The simulation results showed that the marsh land would decrease 2515.44 km2 and the paddy area would increase 19656.24 km2 in the historical development scenario. The marsh land would decrease 303.28 km2, but the paddy area would increase 1392.08 km2 in the planning scenario. The marsh land would increase 3585.61 km2 and the paddy area would increase 289.72 km2 in the ecological restoration scenario. The landscape patterns of the three scenarios were estimated using landscape indices. The results showed that the landscape pattern fragmentation would become more and more serious in the historical development scenario. The landscape pattern would have no signifi-cant changes in the planning scenario. The wetland area and connectivity would increase, the different landscape types would become balanced, and the landscape pattern would be gradually optimized in the ecological restoration scenario.

[Biological properties of Caski cell lines induced by exposing to the space environment].

OBJECTIVE: To investigate the biological properties of Caski cell lines induced by exposing to the space environment. METHODS: Caski cells were carried in "Shen Zhou IV" airship. After 7 days of spaceflight, cells survived and were monocoloned, and the experimental methods such as cell morphological observation, the cell proliferation assay, flow cytometry cell cycle analysis, the soft agar assay, and tumorigenesis assay were used to analyze cell growth characteristics and malignant phenotypes. RESULTS: Altogether 1440 strains subclonal cell lines were established and 4 strains were screened. Compared with the control group, mutated cells appeared to have multiple cell morphological changes. Strains numbered 44F10 and 17E3 were screened due to their increased cell proliferation and tumorigenesis, and their cell cycles were induced to progress from G(1) to S phase, while strains 48A9 and 31F2 were opposite to 44F10 and 17E3 in cytological events. The average population double time of ground nomal control group, ground simulant control group, strains numbered 44F10, 17E3, 48A9 and 31F2 groups were 56.54, 58.44, 52.96, 51.46, 101.76 and 88.47h, respectively; compared with the control group, the average double time of strains numbered 44F10 and 17E3 was decline, but with no statistical significance. However, compared with the control groups, the average double time of 48A9 and 31F2 was significant increased (P<0.05). The colony formation rates were 9.7%, 9.3%, 14.7%, 12.1%, 0 and 0.1%, respectively, and the difference between the ground control groups and the other groups was significant (P<0.01); 6 groups of above-mentioned Caski cells were inoculated subcutaneously in Babl/c nude mice respectively. Forty-seven days later, the formed tumors in the nude mice were statistically analyzed and tested. The average weight of tumors of the above-mentioned groups was 0.066, 0.066, 0.175, 0.249, 0.011 and 0.018g. The difference between the ground control groups and other groups was significant (P<0.05). CONCLUSION: Spaceflight may affect the physiological characteristics of tumor cells and the variation is complicated.

High lncRNA H19 expression as prognostic indicator: data mining in female cancers and polling analysis in non-female cancers.

Upregulation of lncRNA H19 expression is associated with an unfavorable prognosis in some cancers. However, the prognostic value of H19 in female-specific cancers has remained uncharacterized. In this study, the prognostic power of high H19 expression in female cancer patients from the TCGA datasets was analyzed using Kaplan-Meier survival curves and Cox's proportional hazard modeling. In addition, in a meta-analysis of non-female cancer patients from TCGA datasets and 12 independent studies, hazard ratios (HRs) with 95% confidence interval (CI) for overall survival (OS) and disease-free survival (DFS)/relapse-free survival (RFS)/metastasis-free survival (MFS)/progression-free survival (PFS) were pooled to assess the prognostic value of high H19 expression. Kaplan-Meier analysis revealed that patients with uterine corpus cancer and higher H19 expression had a shorter OS (HR=2.710, p<0.05), while females with cervical cancer and increased H19 expression had a shorter RFS (HR=2.261, p<0.05). Multivariate Cox regression analysis showed that high H19 expression could independently predict a poorer prognosis in cervical cancer patients (HR=4.099, p<0.05). In the meta-analysis, patients with high H19 expression showed a poorer outcome in non-female cancer (p<0.05). These results suggest that high lncRNA H19 expression is predictive of an unfavorable prognosis in two female cancers (uterine corpus endometrioid cancer and cervical cancer) as well as in non-female cancer patients.

Alpha-lipoic acid protects against methylmercury-induced neurotoxic effects via inhibition of oxidative stress in rat cerebral cortex.

MeHg is one of the environmental pollutants that lead to oxidative stress and an indirect excitotoxicity caused by altered glutamate (Glu) concentration. However, little was known of the interaction. Therefore, we developed a rat model of MeHg poisoning to explore its neurotoxic effects, and whether LA could attenuate MeHg-induced neurotoxicity. Seventy-two rats were randomly divided into four groups: control group, MeHg-treated groups (4 and 12µmol/kg), and LA pre-treatment group. Administration of the 12µmol/kg MeHg for 4 weeks significantly increased ROS formation that might be critical to aggravate oxidative damages in cerebral cortex. Meanwhile, Glu metabolism as well as GLAST and GLT-1 appeared to be disrupted by MeHg exposure. Pre-treatment of the 35µmol/kg LA significantly prevented MeHg-induced oxidative stress and Glu dyshomoestasis. In conclusion, findings indicated that MeHg could induce oxidative stress and Glu uptake/metabolism disorders in cerebral cortex, LA might antagonize these neurotoxic effects induced by MeHg.

[Spatial distribution of human activities and their influences on landscape patterns in Daqingshan Nature Reserve].

Based on forest inventory data and field survey information, and by using GIS spatial analysis technique and landscape indices, this paper studied the spatial distribution of three categories of human activities (settlement, roads, and other sources of disturbances) and their impacts on landscape patterns in three sub-divided regions, i. e., the west, central and east regions of the Daqingshan Nature Reserve in Inner Mongolia. Results showed that the impacts of human activities were stronger in the east and west regions and weaker in the central region. Among the three subdivided regions, the landscape pattern in the west region was predominantly affected by other sources of disturbances, making the landscape patterns of coniferous forests, broadleaf forests and shrubs tended to be of aggregated distribution; the central region was mainly affected by roads, resulting in reduced landscape patch aggregation of broadleaf forests and shrubs; the east region was mostly affected by settlement, resulting in increased fragmentation of coniferous forests and broadleaf forests and apparent increases in landscape patch aggregation of shrubs and grasslands.

Anti-hepatoma human single-chain Fv antibody and adriamycin conjugates with potent antitumor activity.

To construct an improved biological missile, an immunoconjugate ADM-Dex-ScFv-SA3 was synthesized, which was composed of a hepatocellular carcinoma-specific, single-chain Fv antibody (ScFv-SA3) and a highly potent cytotoxic drug, adriamycin (ADM), as the warhead. Oxidized Dextran T10 (Dex-T10) was used as a linker to connect these two moieties. The 40 KD soluble anti-hepatoma human Trx-ScFv-SA3 protein was expressed in E. coli BL21 (DE3), using a prokaryotic expression vector, pET21a (+)-Trx-ScFv-SA3-His. It was purified using a His-Tag Ni-Agarose column and identified by western blot. The activity of Trx-ScFv-SA3 was verified by enzyme-linked immunosorbent assay (ELISA) and immunocytochemistry to confirm that it specifically binds to the hepatocellular carcinoma cell line HepG2. To prepare ADM-Dex-ScFv-SA3, ADM was conjugated to the antibody at a molar ratio of 14.21:1. The antitumor effect of the conjugate was tested by MTT assay, plate colony formation assay and xenografts in a nude mice experimental model. In vitro experiments revealed that ADM-Dex-ScFv-SA3 could bind to tumor cells selectively and inhibit the proliferation and the colony formation ability of HepG2 cells. In vivo experiments showed that ADM-Dex-ScFv-SA3 suppressed the tumor growth and prolonged the median survival time in tumor-bearing mice. Tumor histology slides indicated a significantly slower tumor tissue proliferation in the ADM-Dex-ScFv-SA3 group. These data indicate that the targeted drug, ADM-Dex-ScFv-SA3, may be a highly potent and selective therapy for the treatment of hepatoma.

[Effects of forest ownership regime on landscape pattern and animal habitat: a review].

In some European and North American countries where forestry is highly developed, both public and private forest ownership regimes have being existed for a long time. Currently, the researches about both the dynamics of forest landscape and habitat pattern and the relationship between habitat pattern and biological conservation in multi-ownership forest landscape are increasingly becoming important. This paper reviewed the effects of multi-ownership regime on forest landscape pattern and animal habitat and emphasized on the ecological consequences of forest parcelization and land divestiture, including the provision of diverse habitats and fragmentation of the existing large-area habitat. This paper also summarized two ways (changing the ownership pattern and integrating the multi-ownership management by cross boundary coordination) for handling the conflicts between small-scaled multi-ownership management and biological conservation at large scale in forestry-developed countries and analyzed the reasons that those countries prefer to adopt the latter one. Furthermore, the methodological limitations in simulating ownership pattern were pointed out. Finally, the present status, challenges and opportunities in the above-mentioned research issues in China were discussed, and the suggestions for further researches were provided.

A monoclonal antibody against the extracellular domain of p75 neurotrophin receptor.

The aim of this study was to prepare and identify a monoclonal antibody against the extracellular domain of p75 neurotrophin receptor (p75NTR-ECD), which will be used in diagnostics, therapeutics, and as a tool in understanding the role of P75NTR in pathogenesis of neuronal degenerative diseases and cancers. In this study, hybridoma technique was used for production of anti-p75NTR-ECD monoclonal antibody. BALB/c mice were immunized with p75NTR-ECD recombinant protein. Hybridoma clones were screened using indirect enzyme-linked immunosorbent assay (ELISA). Anti-p75NTR-ECD monoclonal antibody was produced by ascites revulsion. Protein A affinity chromatography was used for the purification of anti-p75NTR-ECD monoclonal antibody. Titer of anti-p75NTR-ECD was assessed by ELISA. Specificity of anti-p75NTR-ECD was detected by immunofluorescence and immunohistochemistry. As a result, one stable hybridoma cell clone (3B5F9) producing anti-p75NTR-ECD monoclonal antibody was established. The titer of anti-p75NTR-ECD monoclonal antibody is 1:51200. A 2.91 mg monoclonal antibody against p75NTR-ECD with high specificity was prepared. Immunofluorescence and immunohistochemistry showed that p75NTR-ECD positive staining occurs in the plasma membrane of glioma cell and tissue, which results in an advantage in diagnostic and therapeutic targeting of P75NTR expressing neuronal degenerative diseases and cancers.

[Impacts of road network on forest landscape pattern in Great Xing' an Mountains of Northeast China].

By characterizing the composition of road network in the Huzhong Forestry Bureau in Great Xing' an Mountains, Northeast China, we investigated the effects of road networks on landscape pattern by quantifying 1989 landscape pattern for each of the 17 forestry farms on maps with and without roads by principal component analysis (PCA). The results showed that road networks, including the main and secondary timber-transport roads, were distributed evenly among the observed 17 forestry farms with a density of 2.3 m x hm(-2) and spread along the river networks throughout each farm. The emergence of roads significantly altered the landscape pattern at the landscape level in each farm, which was characterized by landscape fragmentation involving a decline in patch area and an increase in patch number and distance among patches. Furthermore, no significant correlation was found between fragmentation and road density. The road network had more impact on fragmentation than on aggregation at the landscape level.

GABA stimulates human hepatocellular carcinoma growth through overexpressed GABAA receptor theta subunit.

AIM: To investigate the function of gamma-aminobutyric acid (GABA) and gamma-aminobutyric acid A receptor θ subunit (GABRQ) in hepatocellular carcinoma (HCC). METHODS: Semiquantitative polymerase chain reaction was used for detecting the expression of GABRQ receptor among HCC cell line HepG2, normal liver cell line L-02, non-malignant Chang's liver cells, 8 samples of HCC tissues and paired non-cancerous tissues. HepG2 cells were treated with GABA at serial concentrations (0, 1, 10, 20, 40 and 60 µmol/L), and their proliferating abilities were analyzed with the methyl thiazolyl tetrazolium assay, cell cycle analysis and tumor implanted in nude mice. Small interfering RNA was used for knocking down the endogenous GABRQ in HepG2. Proliferating abilities of these cells treated with or without GABA were analyzed. RESULTS: We identified the overexpression of GABRQ in HCC cell lines and half of the tested HCC tissues. Knockdown of endogenous GABRQ expression in HepG2 attenuated HCC cell growth, suggesting its role in HCC cell viability. We studied the effect of GABA in the proliferation of GABRQ-positive cell lines in vitro and in vivo, and found that GABA increased HCC growth in a dose-dependent manner. Notably, the addition of GABA into the cell culture medium promoted the proliferation of GABRQ-expressing HepG2 cells, but not GABRQ-knockdown HepG2 cells, which means that GABA stimulates HepG2 cell growth through GABRQ. CONCLUSION: GABRQ play important roles in HCC development and progression and could be a promising molecular target for the development of new diagnostic and therapeutic strategies of HCC.

Preparation of human scFv antibody against nasopharyngeal carcinoma and identification of its specificity.

UNLABELLED: Abstract Conclusion: The selected scFv antibody could specifically recognize and target nasopharyngeal carcinoma (NPC), and could be applied to clinical diagnosis and therapy. OBJECTIVE: The aim was to construct and screen fully human anti-NPC single chain Fv fusion phage libraries, and to identify the specificity of the scFv antibody. METHODS: Peripheral blood mononuclear cells of patients with NPC were immunized in vitro by NPC cells and transformed by Epstein-Barr virus. The total RNAwas used to construct the scFv libraries. By means of ELISA and immunochemistry, the positively bound scFv was selected and identified. The positive scFv was fused to EGFP, and was then expressed in E. coli strain BL21 (DE3) and purified. Furthermore, we observed the binding bioactivity. RESULTS: The fusion protein has the biological activity of binding the NPC cells and emitting green fluorescence. In targeting experiments in vivo, the results showed that the fusion protein can successfully target the NPC.