Investigation of the multiplet features of SrTiO3 in X-ray absorption spectra based on configuration interaction calculations.

Synchrotron-based L2,3-edge absorption spectra show strong sensitivities to the local electronic structure and chemical environment. However, detailed physical information cannot be extracted easily without computational aids. Here, using the experimental Ti L2,3-edges absorption spectrum of SrTiO3 as a fingerprint and considering full multiplet effects, calculations yield different energy parameters characterizing local ground state properties. The peak splitting and intensity ratios of the L3 and L2 set of peaks are carefully analyzed quantitatively, giving rise to a small hybridization energy around 1.2 eV, and the different hybridization energy values reported in the literature are further addressed. Finally, absorption spectra with different linearly polarized photons under various tetragonal crystal fields are investigated, revealing a non-linear orbital-lattice interaction, and a theoretical guidance for material engineering of SrTiO3-based thin films and heterostructures is offered. Detailed analysis of spectrum shifts with different tetragonal crystal fields suggests that the eg crystal field splitting is a necessary parameter for a thorough analysis of the spectra, even though it is not relevant for the ground state properties.

Effects of bisphenol A on decreasing the percentage and promoting the growth of stem cell-like cells from SK-N-SH human neuroblastoma cells.

Bisphenol A (BPA) is an industrial contaminant and is reported to be a risk factor associated with the development of tumors. In our previous studies, we have shown that BPA promoted the growth of SK-N-SH human neuroblastoma cells and increased their invasion and metastasis. In this study, we further investigated the effects of BPA and 17ß-estradiol (E2) on the stem cell-like cells from SK-N-SH cells. Detection of stem cell markers, proliferation assay, and clonogenic analysis showed that the side-population (SP) of SK-N-SH cells had properties similar to those of stem cells. BPA or E2 exposure decreased the percentage of SP cells and the expression of stem cell-marker proteins. BPA and E2 promoted the growth of non-SP cells to a greater extent than of SP cells; in addition, they significantly increased the growth of SP cells. Thus, BPA has effects on stem cell-like cells, which induce tumor formation, and thus, BPA is an environmental factor that plays an important role in the development of neuroblastoma.

Anomalous electronic transport in dual-nanostructured lead telluride.

The Pb- and Sb- dual nanostructured PbTe system exhibits anomalous electronic transport behavior wherein the carrier mobility first increases and then decreases with increase in temperature. By combining in situ transmission electron microscopy observations and theoretical calculations based on energy filtering of charge carriers, we propose a plausible mechanism of charge transport based on interphase potential that is mediated by interdiffusion between coexisting Pb and Sb precipitates. These findings promise new strategies to enhance thermoelectric figure of merit via dual and multinanostructuring of miscible precipitates.

Direct measurement of the low-temperature spin-state transition in LaCoO3.

LaCoO3 exhibits an anomaly in its magnetic susceptibility around 80 K associated with a thermally excited transition of the Co3+-ion spin. We show that electron energy-loss spectroscopy is sensitive to this Co3+-ion spin-state transition, and that the O K edge prepeak provides a direct measure of the Co3+ spin state in LaCoO3 as a function of temperature. Our experimental results are confirmed by first-principles calculations, and we conclude that the thermally excited spin-state transition occurs from a low to an intermediate spin state, which can be distinguished from the high-spin state.

[Application of right jugular vessels to build extracorporeal membrane oxygenation for treating the critically ill children].

OBJECTIVE: To summarize the experience in applying a technique of inserting a cannula through right internal jugular vein and common carotid artery to build extracorporeal membrane oxygenation (ECMO) for critically ill children. METHOD: The data of critically ill patients received ECMO support through right internal jugular vein and common carotid artery between December 2011 and December 2015 from Children's Hospital of Fudan University were analyzed retrospectively.The data included diagnosis, age, body weight, time of cannula and ECMO running, complication and prognosis. RESULT: In total 28 patients received ECMO support, 3 patients of post-cardiac surgery with transthoracic cannula were excluded.Twenty-five patients inserted cannula through neck vessels were enrolled, 15 boys and 10 girls, the median age was 1.8 years (range, 1 d-13 years), the median weight was 12.0 (2.8-50.0) kg.All the cannula sites were right internal jugular vein and right common carotid artery, before cannula use 5 patients had been inserted central vein tube and 3 patients with blood filter tube in right internal jugular vein, in one case cannula was applied during cardiopulmonary resuscitation.V-A ECMO had been built for all the cases successfully, the median operation time was (45±26) min.The pump flow was 80-150 ml/(kg·min), the median duration of ECMO support was 153(14-567) h. Sixteen (64%) patients weaned off ECMO successfully, 15(60%) survived to hospital discharge.About the complication of cannula, six patients developed cannula site bleeding, and two patients required re-fixation of cannula, one patient's external jugular vein had been hurt and sutured for bleeding. CONCLUSION: Application of right jugular vessels to build ECMO is easy and safe for treating the sick children. The skill should be proficient to assure ECMO run and reduce the complications.

CXCR7 Participates in CXCL12-mediated Cell Cycle and Proliferation Regulation in Mouse Neural Progenitor Cells.

BACKGROUND: Cell cycle regulation of neural progenitor cells (NPCs) is an essential process for neurogenesis, neural development, and repair after brain trauma. Stromal cell-derived factor-1 (SDF-1, CXCL12) and its receptors CXCR4 and CXCR7 are well known in regulating the migration and survival of NPCs. The effects of CXCL12 on NPCs proliferation, cell cycle regulation, and their associated signaling pathways remain unclear. Cyclin D1 is a protein required for progression through the G1 phase of the cell cycle and a known downstream target of ß -catenin. Therefore, cyclin D1 plays critical roles of cell cycle regulation, proliferation, and survival in NPCs. METHODS: Primary mouse NPCs (mNPCs) were derived from brain tissues of wild-type, Cxcr4 knockout, or Cxcr7 knockout mice at mouse embryonic day 13.5 (E13.5). Flow cytometry was used to perform cell cycle analysis by quantitation of DNA content. Real-time PCR and Western blot were used to evaluate mRNA and protein expressions, respectively. Ki67 immunostaining and TUNEL assay were used to assess the proliferation and survival of mNPCs, respectively. RESULTS: CXCL12 pretreatment led to the shortening of G0/G1 phase and lengthening of S phase, suggesting that CXCL12 regulates cell cycle progression in mNPCs. Consistently, CXCL12 treatment increased the expression of CyclinD1 and ß -catenin, and promoted proliferation and survival of mNPCs. Cxcr7 knockout of mNPCs blocked CXCL12-mediated mNPCs proliferation, whereas Cxcr4 knockout mNPC did not significantly effect CXCL12- mediated mNPCs proliferation. CONCLUSION: CXCR7 plays an important role in CXCL12-mediated mNPC cell cycle regulation and proliferation.

A new iridovirus isolated from soft-shelled turtle.

A virus was isolated from soft-shelled turtle (Trionyx sinensis) with 'red neck disease' on a farm in Shenzhen, China, the virus multiplied and caused a cytopathogenic effect (CPE) at 15-30 degrees C in CO, FHM, CK and BF-2 cells. The optimum conditions for replication was in CO cells at 25-30 degrees C. The virus was sensitive to chloroform treatment, acid (pH 3) or alkaline (pH 10) conditions and heating at 56 degrees C for 30 min. Treatment with 5-iodo-2-deoxyuridine (IUDR) inhibited viral replication, indicating the presence of a DNA genome. Electron microscopy of infected CO culture fluid revealed spherical particles measuring 120-160 nm in diameter. Observation of ultra-thin sections showed numerous hexagonal viral particles in the cytoplasm and nucleus of cells typical of an iridovirus. This virus was moderately virulent for turtles in infection tests. We suggest that this virus is named soft-shelled turtle iridovirus (STIV).

A novel role of the STAT3 pathway in brain inflammation-induced human neural progenitor cell differentiation.

Brain inflammation is a primary pathological driving force of many neurodegenerative disorders. In the destructive process, pro-inflammatory cytokines (IL-1ß and TNF-α), are robustly released, affecting normal neural progenitor cell (NPC) differentiation, and resulting in a vast number of astrocytes and a diminished neural population. A counteractive mechanism is still unknown. In this study, we have identified a link between brain inflammation and the signal transducer and activator of transcription 3 (STAT3) pathway: IL-1ß and TNF-α induce STAT3 activation in NPCs. Then to investigate STAT3's effects on NPC fate, we observed that an inhibition of STAT3 expression by siRNA inhibited astrocytic differentiation and increased neuronal differentiation of human NPCs in fetal bovine serum (FBS)-induced astrocyte differentiation condition. Furthermore, STAT3-targeting siRNA abrogated IL-1ß and TNF-α-induced astrocyte differentiation and partially restored neuronal differentiation. Elimination of STAT3 expression also countered IL-1ß and TNF-α-induced inhibition of proneural bHLH genes, mammalian achaete-schute homologue-1 (Mash1), Neurogenin1 (Ngn1), and Neurogenin2 (Ngn2). These data suggest that a suppression of STAT3 during brain inflammation would inhibit astrogliogenesis and promote neurogenesis. Thus, STAT3 could be a potential target of drug therapy for neurodegenerative disorders.

Direct conversion of dermal fibroblasts into neural progenitor cells by a novel cocktail of defined factors.

The generation of functional neural progenitor cells (NPCs) independent of donor brain tissue and embryonic tissues is of great therapeutic interest with regard to regenerative medicine and the possible treatment of neurodegenerative disorders. Traditionally, NPCs are derived through the differentiation of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). However, the induction of NPCs from ESCs and iPSCs is a complicated process that increases the risk of neoplasia and undesired cell types. This process can be circumvented through the direct conversion of somatic cells from one cell type to another by ectopic expression of specifically defined transcription factors. Using gene expression profiling and parental cells from E/Nestin:EGFP transgenic mice as a monitoring system, we tested nine factors with the potential to directly convert fibroblasts into NPCs. We found that five of these factors can directly convert adult dermal fibroblasts into NPC-like cells (iNPCs), and the resulting iNPCs possessed similar properties as primary NPCs including proliferation, self-renewal and differentiation. Significantly, iNPCs also exhibit chemotactic properties similar to those of primary NPCs. These provide an important alternative strategy to generate iNPCs for cell replacement therapy of neurodegenerative diseases.

Nanoscale disorder in CaCu3Ti4O12: a new route to the enhanced dielectric response.

Significant nanoscale disorder of Cu and Ca atomic substitution is observed in CaCu(3)Ti(4)O(12), based on our integrated study using quantitative electron diffraction and extended x-ray absorption fine structure. Unambiguous identification of this previously omitted disorder is made possible by the unique sensitivity of these probes to valence-electron distribution and short-range order. Furthermore, first-principles-based theoretical analysis indicates that the Ca-site Cu atoms possess partially filled degenerate e(g) states, suggesting significant boost of dielectric response from additional low-energy electronic contributions. Our study points to a new route of enhancing dielectric response in transitional metal oxides by exploiting the strong electronic correlation beyond classical static pictures.