Showing papers by "Chao Zhang published in 2012"

RAS mutations in cutaneous squamous-cell carcinomas in patients treated with BRAF inhibitors.

Abstract: Background Cutaneous squamous-cell carcinomas and keratoacanthomas are common findings in patients treated with BRAF inhibitors. Methods We performed a molecular analysis to identify oncogenic mutations (HRAS, KRAS, NRAS, CDKN2A, and TP53) in the lesions from patients treated with the BRAF inhibitor vemurafenib. An analysis of an independent validation set and functional studies with BRAF inhibitors in the presence of the prevalent RAS mutation was also performed. Results Among 21 tumor samples, 13 had RAS mutations (12 in HRAS). In a validation set of 14 samples, 8 had RAS mutations (4 in HRAS). Thus, 60% (21 of 35) of the specimens harbored RAS mutations, the most prevalent being HRAS Q61L. Increased proliferation of HRAS Q61L–mutant cell lines exposed to vemurafenib was associated with mitogen-activated protein kinase (MAPK)–pathway signaling and activation of ERK-mediated transcription. In a mouse model of HRAS Q61L–mediated skin carcinogenesis, the vemurafenib analogue PLX4720 was not an initiator or...

Vemurafenib: the first drug approved for BRAF -mutant cancer

Abstract: The identification of driver oncogenes has provided important targets for drugs that can change the landscape of cancer therapies. One such example is the BRAF oncogene, which is found in about half of all melanomas as well as several other cancers. As a druggable kinase, oncogenic BRAF has become a crucial target of small-molecule drug discovery efforts. Following a rapid clinical development path, vemurafenib (Zelboraf; Plexxikon/Roche) was approved for the treatment of BRAF-mutated metastatic melanoma in the United States in August 2011 and the European Union in February 2012. This Review describes the underlying biology of BRAF, the technology used to identify vemurafenib and its clinical development milestones, along with future prospects based on lessons learned during its development.

Rapid self-healing hydrogels.

Abstract: Synthetic materials that are capable of autonomous healing upon damage are being developed at a rapid pace because of their many potential applications. Despite these advancements, achieving self-healing in permanently cross-linked hydrogels has remained elusive because of the presence of water and irreversible cross-links. Here, we demonstrate that permanently cross-linked hydrogels can be engineered to exhibit self-healing in an aqueous environment. We achieve this feature by arming the hydrogel network with flexible-pendant side chains carrying an optimal balance of hydrophilic and hydrophobic moieties that allows the side chains to mediate hydrogen bonds across the hydrogel interfaces with minimal steric hindrance and hydrophobic collapse. The self-healing reported here is rapid, occurring within seconds of the insertion of a crack into the hydrogel or juxtaposition of two separate hydrogel pieces. The healing is reversible and can be switched on and off via changes in pH, allowing external control over the healing process. Moreover, the hydrogels can sustain multiple cycles of healing and separation without compromising their mechanical properties and healing kinetics. Beyond revealing how secondary interactions could be harnessed to introduce new functions to chemically cross-linked polymeric systems, we also demonstrate various potential applications of such easy-to-synthesize, smart, self-healing hydrogels.

Re-emerging superconductivity at 48 kelvin in iron chalcogenides

Abstract: Pressure has an essential role in the production(1) and control(2,3) of superconductivity in iron-based superconductors. Substitution of a large cation by a smaller rare-earth ion to simulate the pressure effect has raised the superconducting transition temperature T-c to a record high of 55 K in these materials(4,5). In the same way as T-c exhibits a bell-shaped curve of dependence on chemical doping, pressure-tuned T-c typically drops monotonically after passing the optimal pressure(1-3). Here we report that in the superconducting iron chalcogenides, a second superconducting phase suddenly re-emerges above 11.5 GPa, after the T-c drops from the first maximum of 32 K at 1 GPa. The T-c of the re-emerging superconducting phase is considerably higher than the first maximum, reaching 48.0-48.7 K for Tl0.6Rb0.4Fe1.67Se2, K0.8Fe1.7Se2 and K0.8Fe1.78Se2.

Cyclin-dependent kinase control of the initiation-to-elongation switch of RNA polymerase II

Abstract: RNA polymerase II (pol II) frequently pauses in the promoter-proximal region to ensure gene-specific regulation and RNA quality control. New research demonstrates that the cyclin-dependent kinase Cdk7 can act to establish the promoter-proximal pause, through its control of the TFIIE-DSIF switch, and to release Pol II from the pause, through its ability to activate Cdk9.

Room temperature giant and linear magnetoresistance in topological insulator Bi2Te3 nanosheets

Abstract: Topological insulators, a new class of condensed matter having bulk insulating states and gapless metallic surface states, have demonstrated fascinating quantum effects. However, the potential practical applications of the topological insulators are still under exploration worldwide. We demonstrate that nanosheets of a ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$ topological insulator several quintuple layers thick display giant and linear magnetoresistance. The giant and linear magnetoresistance achieved is as high as over 600% at room temperature, with a trend towards further increase at higher temperatures, as well as being weakly temperature-dependent and linear with the field, without any sign of saturation at measured fields up to 13 T. Furthermore, we observed a magnetic field induced gap below 10 K. The observation of giant and linear magnetoresistance paves the way for 3D topological insulators to be useful for practical applications in magnetoelectronic sensors such as disk reading heads, mechatronics, and other multifunctional electromagnetic applications.

Hybridization of graphene sheets and carbon-coated Fe3O4 nanoparticles as a synergistic adsorbent of organic dyes

Abstract: Magnetic graphene–Fe3O4@carbon (GFC) hybrids with hierarchical nanostructures have been synthesized and their application as an adsorbent for the removal of organic dyes has been investigated. Graphene–Fe3O4 hybrids were first prepared via a facile one-pot solvothermal process, then carbonaceous coatings on Fe3O4 nanoparticles of nanometer thickness were synthesized by a hydrothermal carbonization process using eco-friendly glucose as a carbon source. Graphene sheets acting as two-dimensional (2D) substrates can effectively prevent the Fe3O4 nanoparticles from aggregating and enable a good dispersion of these magnetic nanoparticles. The carbonaceous layer protects the Fe3O4 nanoparticles in acidic environments and greatly enhances the specific surface area of the hybrids which is beneficial for the removal of organic dyes, such as methylene blue (MB). The resultant GFC hybrids exhibit great adsorption properties not only in water but also in acidic environments, and about 86% and 77% of the dye removal efficiency can be retained after five adsorption–desorption cycles in water and 1 M HCl, respectively. The rapid and efficient adsorption of organic dyes from water as well as acid suggests that the GFC hybrids have potential environmental applications as alternatives to commercial materials in wastewater treatment for the removal of organic dyes.

Immobilization of Co-Al layered double hydroxides on graphene oxide nanosheets: growth mechanism and supercapacitor studies.

Abstract: Layered double hydroxides (LDHs) are generally expressed as [M2+1–xM3+x (OH)2] [An–x/n·mH2O], where M2+ and M3+ are divalent and trivalent metal cations respectively, and A is n-valent interlayer guest anion. Co–Al layered double hydroxides (LDHs) with different sizes have been grown on graphene oxide (GO) via in situ hydrothermal crystallization. In the synthesis procedure, the GO is partially reduced in company with the formation of Co–Al LDHs. The morphology and structure of LDHs/GO hybrids are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The growth mechanism of LDHs on GO nanosheets is discussed. Moreover, both LDHs and LDHs/graphene nanosheets (GNS) hybrids are further used as electrochemical supercapacitor materials and their performance is evaluated by cyclic voltammetry (CV) and galvanostatic charge/discharge measurements. It is shown that the specific capacitance...

Facile preparation of water-dispersible graphene sheets stabilized by acid-treated multi-walled carbon nanotubes and their poly(vinyl alcohol) composites†

Abstract: Graphene has attracted tremendous interest in reinforcing fillers due to its unique structure and excellent physical properties. However, efficient reinforcement has been largely limited because graphene tends to agglomerate within a polymer matrix. In this study, direct reduction of graphene oxide (GO) in water in the presence of acid-treated multi-walled carbon nanotubes (t-CNTs) results in a homogeneous dispersion of reduced graphene oxide (r-GO) and t-CNT hybrids. The three-dimensional r-GO/t-CNTs hybrids (abbreviated as G-CNT hybrids) possess unique properties, making them ideal reinforcing fillers for polymer nanocomposites. Poly(vinyl alcohol) (PVA) composite containing G-CNT hybrids is then prepared by a simple water casting method. Due to the synergistic interaction of the two kinds of nanofillers, the tensile strength and Young's modulus of the resulting PVA nanocomposite filled with only 0.6 wt% G-CNT hybrids are significantly improved by about 77% and 65%, respectively. The results indicate that the nanohybrids are well dispersed throughout the PVA matrix and form strong interfacial interactions with the matrix. Besides, the presence of G-CNT hybrids slightly increases the thermal stability at 5% weight loss and remarkably improves the amount of residues of PVA nanocomposites. For comparison, we also prepare a PVA composite with the addition of only t-CNTs and find that its mechanical properties show limited enhancement owing to the decreased length-to-diameter ratio and structural defects of CNTs by acid treatment. Our work therefore provides a new way for the preparation of hybrid carbon nanomaterials with unique structure and excellent properties for fabricating high-performance polymer nanocomposites.

Orm protein phosphoregulation mediates transient sphingolipid biosynthesis response to heat stress via the Pkh-Ypk and Cdc55-PP2A pathways

Abstract: This study reveals the basis for how temporal phosphoregulation of Orm protein controls sphingolipid production in response to stress. Orm protein phosphorylation is highly responsive to sphingoid ...

Evaluating geo-social influence in location-based social networks

Abstract: The emerging location-based social network (LBSN) services not only allow people to maintain cyber links with their friends, but also enable them to share the events happening on them at different locations. The geo-social correlations among event participants make it possible to quantify mutual user influence for various events. Such a quantification of influence could benefit a wide spectrum of real-life applications such as targeted advertising and viral marketing. In this paper, we perform an in-depth analysis of the geo-social correlations among LBSN users at event level, based on which we address two problems: user influence evaluation and influential events discovery. To capture the geo-social closeness between LBSN users, we propose a unified influence metric. This metric combines a novel social proximity measure named penalized hitting time, with a geographical weight function modeled by power law distribution. We propose two approximate algorithms, namely global iteration (GI) and dynamic neighborhood expansion (DNE), to efficiently evaluate user influence with tight theoretical error bounds. We then adopt the sampling technique and the threshold algorithm to support efficient retrieval of top-K influential events. Extensive experiments on both real-life and synthetic LBSN data sets confirm that the proposed algorithms are effective, efficient, and scalable.

Tracing the evolution and distribution of F and Cl in plutonic systems from volatile-bearing minerals: a case study from the Liujiawa pluton (Dabie orogen, China)

Abstract: Fluorine and chlorine play an important role in magmatic differentiation, hydrothermal alteration, and related mineralization processes, but tracing their evolution in magmatic and especially plutonic systems is not an easy task. The F and Cl in melts can be estimated from F and Cl concentrations in minerals, provided that partitioning between minerals and melts are constrained. Based on available partitioning models between mineral/melt, mineral/fluid, and melt/fluid, a set of equations has been derived to determine F and Cl concentrations in melts from the compositions of amphibole, biotite, and apatite. The new calculation procedure has been applied to a plutonic system, the Liujiawa pluton, eastern Dabie orogen (China). Cl and F concentrations in amphiboles, biotites, and apatites from different rock types (gabbronorite, two-pyroxene diorite, clinopyroxene diorite, and hornblende gabbro) have been determined by electron microprobe. Most amphiboles show a negative correlation between log(Cl/OH) and Mg-number and a positive correlation between log(F/OH) and A-site occupation. Biotites from the gabbronorite and two-pyroxene diorite show a slight positive correlation between log(Cl/OH) and Mg, which is however not the case for the clinopyroxene diorite. Apatites from all the samples are rich in F and show negative correlations between Cl and F concentrations. In our case study, we demonstrate that the Cl concentration in melt remains approximately constant at 1,000–2,000 ppm over the major crystallization interval, but decreases strongly at near solidus temperatures as a result of fluid exsolution. The F concentration in melt remains nearly constant at ca. 2,000–3,000 ppm at high temperatures as well as near solidus conditions, indicating that it is not largely affected by fluid exsolution because of its strongly preferred incorporation into melt. Interestingly, the evolution of Cl and F concentrations in melt with magmatic differentiation is similar to that determined in volcanic systems, suggesting that the evolution of Cl and F in melts during crystallization and late magmatic stages at depth (plutonic systems) is similar to that observed in volcanic systems during decompression and degassing.

All-carbon electrode-based fiber-shaped dye-sensitized solar cells

Abstract: A novel fiber-shaped dye-sensitized solar cell (DSSC) based on an all-carbon electrode is presented, where low-cost, highly-stable, and biocompatible carbon materials are applied to both the photoanode and the counter electrode. The fibrous carbon-based photoanode has a core–shell structure, with carbon fiber core used as conductive substrate to collect carriers and sensitized porous TiO2 film as shell to harvest light effectively. The highly catalytic all-carbon counter electrode is made from ink carbon coatings and carbon fiber substrate. Results show that the open circuit voltage can be largely improved through engineering at the carbon fiber/TiO2 interface. An optimized diameter of the photoanode results in an efficiency of 1.9%. It is the first demonstration of efficient DSSCs based on all-carbon electrodes, and the devices are totally free from TCOs or any other expensive electrode materials. Also, this type of solar cell is significant in obtaining bio-friendly all-carbon photovoltaics suitable for large-scale production.

Generalization Bounds for Domain Adaptation

Abstract: In this paper, we provide a new framework to study the generalization bound of the learning process for domain adaptation. We consider two kinds of representative domain adaptation settings: one is domain adaptation with multiple sources and the other is domain adaptation combining source and target data. In particular, we use the integral probability metric to measure the difference between two domains. Then, we develop the specific Hoeffding-type deviation inequality and symmetrization inequality for either kind of domain adaptation to achieve the corresponding generalization bound based on the uniform entropy number. By using the resultant generalization bound, we analyze the asymptotic convergence and the rate of convergence of the learning process for domain adaptation. Meanwhile, we discuss the factors that affect the asymptotic behavior of the learning process. The numerical experiments support our results.

Chemical-genetic analysis of cyclin dependent kinase 2 function reveals an important role in cellular transformation by multiple oncogenic pathways

Abstract: A family of conserved serine/threonine kinases known as cyclin-dependent kinases (CDKs) drives orderly cell cycle progression in mammalian cells. Prior studies have suggested that CDK2 regulates S-phase entry and progression, and frequently shows increased activity in a wide spectrum of human tumors. Genetic KO/knockdown approaches, however, have suggested that lack of CDK2 protein does not prevent cellular proliferation, both during somatic development in mice as well as in human cancer cell lines. Here, we use an alternative, chemical-genetic approach to achieve specific inhibition of CDK2 kinase activity in cells. We directly compare small-molecule inhibition of CDK2 kinase activity with siRNA knockdown and show that small-molecule inhibition results in marked defects in proliferation of nontransformed cells, whereas siRNA knockdown does not, highlighting the differences between these two approaches. In addition, CDK2 inhibition drastically diminishes anchorage-independent growth of human cancer cells and cells transformed with various oncogenes. Our results establish that CDK2 activity is necessary for normal mammalian cell cycle progression and suggest that it might be a useful therapeutic target for treating cancer.

Electrical and thermoelectric properties of single- wall carbon nanotube doped Bi2Te3

Abstract: The effects of single-wall carbon nanotube (SWCNT) doping in n-type Bi2Te3 bulk samples on the electrical and thermal transport properties have been studied. Bi2Te3 samples doped with 0–5 wt. % SWCNTs were fabricated using solid state reaction and investigated using x-ray diffraction, transmission electron microscopy, and magneto transport measurements. Results show that the 0.5% doping results in the significant enhancement of the Seebeck coefficience to as high as −231.8 μV/K, giant magneto resistance of up to 110%, reduction of thermal conductivity, and change of sign of the Seebeck coefficient from n to p type depending on the doping level and temperature. The figure of merit, ZT, of the optimum SWCNT doped Bi2Te3 was increased by 25%–40% over a wide temperature range compared to the undoped sample.

Glacier changes from 1966-2009 in the Gongga Mountains, on the south-eastern margin of the Qinghai-Tibetan Plateau and their climatic forcing

Abstract: In order to monitor the changes of the glaciers in the Gongga Mountain region on the south-eastern margin of the Qinghai-Tibetan Plateau, 74 monsoonal temperate glaciers were investigated by comparing the Chinese Glacier Inventory (CGI), recorded in the 1960s, with Landsat MSS in 1974, Landsat TM in 1989, 1994, 2005, and ASTER data in 2009 The remote sensing data have been applied to map the glacier outline by threshold ratio images (TM4/TM5) Moreover, the glacier outlines were verified by GPS survey on four large glaciers (Hailuogou (HLG), Mozigou (MZG), Yanzigou (YZG), and Dagongba (DGB)) in 2009 The results show that the area dominated by the 74 glaciers has shrunk by 113% (292 km 2 ) from 1966 to 2009 Glacier area on the eastern and western slopes of the Gongga Mountains decreased by 98% and 146% since 1966, respectively The loss in glacier area and length is, respectively, 08 km 2 and 11464 m for the HLG Glacier, 21 km 2 and 5018 m for the MZG Glacier, 08 km 2 and 7248 m for the YZG Glacier, and 24 km 2 and 10023 m for the DGB Glacier Decades of climate records obtained from three meteorological stations in the Gongga Mountains were analyzed to evaluate the impact of the temperature and precipitation on glacier retreat The mean annual temperatures over the eastern and western slopes of the Gongga Mountains have been increasing by 034 K decade −1 and 024 K decade −1 (1988–2009), respectively Moreover, mean annual precipitation has only increased by 1% in the past 50 yr The increasing amount of precipitation could not compensate for the glacier mass loss due to the temperature increase in the Gongga Mountains This suggests that the warming of the climate is probably also responsible for the glacier retreat in the study region At the region scale, glacier changes were also controlled by local topographical factors

Chemical Genetics Reveals a Specific Requirement for Cdk2 Activity in the DNA Damage Response and Identifies Nbs1 as a Cdk2 Substrate in Human Cells

Abstract: The cyclin-dependent kinases (CDKs) that promote cell-cycle progression are targets for negative regulation by signals from damaged or unreplicated DNA, but also play active roles in response to DNA lesions. The requirement for activity in the face of DNA damage implies that there are mechanisms to insulate certain CDKs from checkpoint inhibition. It remains difficult, however, to assign precise functions to specific CDKs in protecting genomic integrity. In mammals, Cdk2 is active throughout S and G2 phases, but Cdk2 protein is dispensable for survival, owing to compensation by other CDKs. That plasticity obscured a requirement for Cdk2 activity in proliferation of human cells, which we uncovered by replacement of wild-type Cdk2 with a mutant version sensitized to inhibition by bulky adenine analogs. Here we show that transient, selective inhibition of analog-sensitive (AS) Cdk2 after exposure to ionizing radiation (IR) enhances cell-killing. In extracts supplemented with an ATP analog used preferentially by AS kinases, Cdk2as phosphorylated the Nijmegen Breakage Syndrome gene product Nbs1—a component of the conserved Mre11-Rad50-Nbs1 complex required for normal DNA damage repair and checkpoint signaling—dependent on a consensus CDK recognition site at Ser432. In vivo, selective inhibition of Cdk2 delayed and diminished Nbs1-Ser432 phosphorylation during S phase, and mutation of Ser432 to Ala or Asp increased IR–sensitivity. Therefore, by chemical genetics, we uncovered both a non-redundant requirement for Cdk2 activity in response to DNA damage and a specific target of Cdk2 within the DNA repair machinery.

A review on hybridization modification of graphene and its polymer nanocomposites

Abstract: Recently, graphene has attracted numerous interests from both fundamental and applied fields due to its excellent mechanical, thermal, electrical conductivity and other novel properties. This review gives an overview of recent progress on hybridization modifications of graphene with carbon nanomaterials. Some example applications of graphene-based nanohybrids in polymer composites, optical and conducting materials, high performance electrolyte materials and as well as other functional materials are summarized and discussed.

Room-temperature strong terahertz photon mixing in graphene

Abstract: We demonstrate that single layer graphene exhibits a strong nonlinear photon-mixing effect in the terahertz frequency regime. Up to room temperature, the third-order nonlinear current in graphene grows rapidly with increasing temperature. The third-order nonlinear current can be as strong as the linear current under a moderate electric field strength of 104 V/cm. Because of the unique Dirac behavior of the graphene quasi-particles, low Fermi level and electron fillings optimizes the optical nonlinearity. Under a strong-field condition, the strong-field-induced Dirac fermion population redistribution and nonequilibrium carrier heating effects further amplify the optical nonlinearity of graphene. Our results suggest that doped graphene can potentially be utilized as a strong terahertz photon mixer in the room-temperature regime.

A Positive Feedback Loop Links Opposing Functions of P-TEFb/Cdk9 and Histone H2B Ubiquitylation to Regulate Transcript Elongation in Fission Yeast

Abstract: Transcript elongation by RNA polymerase II (RNAPII) is accompanied by conserved patterns of histone modification. Whereas histone modifications have established roles in transcription initiation, their functions during elongation are not understood. Mono-ubiquitylation of histone H2B (H2Bub1) plays a key role in coordinating co-transcriptional histone modification by promoting site-specific methylation of histone H3. H2Bub1 also regulates gene expression through an unidentified, methylation-independent mechanism. Here we reveal bidirectional communication between H2Bub1 and Cdk9, the ortholog of metazoan positive transcription elongation factor b (P-TEFb), in the fission yeast Schizosaccharomyces pombe. Chemical and classical genetic analyses indicate that lowering Cdk9 activity or preventing phosphorylation of its substrate, the transcription processivity factor Spt5, reduces H2Bub1 in vivo. Conversely, mutations in the H2Bub1 pathway impair Cdk9 recruitment to chromatin and decrease Spt5 phosphorylation. Moreover, an Spt5 phosphorylation-site mutation, combined with deletion of the histone H3 Lys4 methyltransferase Set1, phenocopies morphologic and growth defects due to H2Bub1 loss, suggesting independent, partially redundant roles for Cdk9 and Set1 downstream of H2Bub1. Surprisingly, mutation of the histone H2B ubiquitin-acceptor residue relaxes the Cdk9 activity requirement in vivo, and cdk9 mutations suppress cell-morphology defects in H2Bub1-deficient strains. Genome-wide analyses by chromatin immunoprecipitation also demonstrate opposing effects of Cdk9 and H2Bub1 on distribution of transcribing RNAPII. Therefore, whereas mutual dependence of H2Bub1 and Spt5 phosphorylation indicates positive feedback, mutual suppression by cdk9 and H2Bub1-pathway mutations suggests antagonistic functions that must be kept in balance to regulate elongation. Loss of H2Bub1 disrupts that balance and leads to deranged gene expression and aberrant cell morphologies, revealing a novel function of a conserved, co-transcriptional histone modification.

High-level expression of Notch1 increased the risk of metastasis in T1 stage clear cell renal cell carcinoma.

Abstract: Background Although metastasis of clear cell renal cell carcinoma (ccRCC) is basically observed in late stage tumors, T1 stage metastasis of ccRCC can also be found with no definite molecular cause resulting inappropriate selection of surgery method and poor prognosis. Notch signaling is a conserved, widely expressed signal pathway that mediates various cellular processes in normal development and tumorigenesis. This study aims to explore the potential role and mechanism of Notch signaling in the metastasis of T1 stage ccRCC. Methodology/Principal Findings The expression of Notch1 and Jagged1 were analyzed in tumor tissues and matched normal adjacent tissues obtained from 51 ccRCC patients. Compared to non-tumor tissues, Notch1 and Jagged1 expression was significantly elevated both in mRNA and protein levels in tumors. Tissue samples of localized and metastatic tumors were divided into three groups based on their tumor stages and the relative mRNA expression of Notch1 and Jagged1 were analyzed. Compared to localized tumors, Notch1 expression was significantly elevated in metastatic tumors in T1 stage while Jagged1 expression was not statistically different between localized and metastatic tumors of all stages. The average size of metastatic tumors was significantly larger than localized tumors in T1 stage ccRCC and the elevated expression of Notch1 was significantly positive correlated with the tumor diameter. The functional significance of Notch signaling was studied by transfection of 786-O, Caki-1 and HKC cell lines with full-length expression plasmids of Notch1 and Jagged1. Compared to the corresponding controls, all cell lines demonstrated significant promotion in cell proliferation and migration while cell cycle remained unaffected. Conclusions/Significance High-level expression of Notch signaling increased the risk of metastasis in T1 stage ccRCC by stimulating the proliferation and migration of tumor cells, which may be helpful for the selection of suitable operation method and prognosis of ccRCC.

The effect of Fe2+ ions on dielectric and magnetic properties of Yb3Fe5O12 ceramics

Abstract: Yb3Fe5O12 ceramics with garnet structure were prepared employing the solid-state reaction method. The results reveal that the emergence of Fe2+ ions greatly affects dielectric relaxation, magnetic relaxation, saturation magnetization, and magnetoelectric coupling, which was further confirmed by oxygen treatment. More interestingly, the magnetoelectric coefficient (α) reaches 28 ps m−1 at room temperature, which is among the largest values for present single-phase magnetoelectric materials.

Coseeded Schwann cells myelinate neurites from differentiated neural stem cells in neurotrophin-3-loaded PLGA carriers

Abstract: Biomaterials and neurotrophic factors represent promising guidance for neural repair. In this study, we combined poly-(lactic acid-co-glycolic acid) (PLGA) conduits and neurotrophin-3 (NT-3) to generate NT-3-loaded PLGA carriers in vitro. Bioactive NT-3 was released stably and constantly from PLGA conduits for up to 4 weeks. Neural stem cells (NSCs) and Schwann cells (SCs) were coseeded into an NT-releasing scaffold system and cultured for 14 days. Immunoreactivity against Map2 showed that most of the grafted cells (>80%) were differentiated toward neurons. Double-immunostaining for synaptogenesis and myelination revealed the formation of synaptic structures and myelin sheaths in the coculture, which was also observed under electron microscope. Furthermore, under depolarizing conditions, these synapses were excitable and capable of releasing synaptic vesicles labeled with FM1-43 or FM4-64. Taken together, coseeding NSCs and SCs into NT-3-loaded PLGA carriers increased the differentiation of NSCs into neurons, developed synaptic connections, exhibited synaptic activities, and myelination of neurites by the accompanying SCs. These results provide an experimental basis that supports transplantation of functional neural construction in spinal cord injury.