Topological surface state in the Kondo insulator samarium hexaboride

Topological invariants of electron wavefunctions in condensed matter reveal many intriguing phenomena. A notable example is provided by topological insulators, which are characterized by an insulating bulk coexisting with a metallic boundary state. Although there has been intense interest in Bi-based topological insulators, their behaviour is complicated by the presence of a considerable residual bulk conductivity. Theories predict that the Kondo insulator system SmB6, which is known to undergo a transition from a Kondo lattice metal to a small-gap insulator state with decreasing temperature, could be a topological insulator. Although the insulating bulk and metallic surface separation has been demonstrated in recent transport measurements, these have not demonstrated the topologically protected nature of the metallic surface state. Here we report thickness-dependent transport measurements on doped SmB6, and show that magnetic and non-magnetic doping results in contrasting behaviour that supports the conclusion that SmB6 shows virtually no residual bulk conductivity.

Three-dimensional visualization of rat brain microvasculature following permanent focal ischaemia by synchrotron radiation

OBJECTIVE

Identifying morphological changes that occur in microvessels under both normal and ischaemic conditions is crucial for understanding and treating stroke. However, conventional imaging techniques are not able to detect microvessels on a micron or sub-micron scale without angiography. In the present study, synchrotron radiation (SR)-based X-ray in-line phase contrast imaging (ILPCI) was used to acquire high-resolution and high-contrast images of rat brain tissues in both normal and ischaemic states.

METHODS

ILPCI was performed at the Shanghai Synchrotron Radiation Facility, Shanghai, China, without the use of contrast agents. CT slices were reformatted and then converted into three-dimensional (3D) reconstruction images to analyse subtle details of the cerebral microvascular network.

RESULTS

By using ILPCI, brain vessels up to 11.8 μm in diameter were resolved. The number of cortical and penetrating arteries detected were found to undergo a remarkable decrease within the infarct area. 3 days after permanent ischaemia, vascular masses were also observed in the peripheral region of the infarcts.

CONCLUSION

SR-based ILPCI-CT can serve as a powerful tool to accurately visualize brain microvasculature. The morphological parameters of blood vessels in both CT slices and 3D reconstructions were determined, and this approach has great potential for providing an effective diagnosis and evaluation for rehabilitation therapy for stroke.

ADVANCES IN KNOWLEDGE

In the absence of contrast agent, the 3D morphologies of the brain microvasculature in normal and stroke rats were obtained using SR-based ILPCI. SR imaging is a sensitive and promising method which can be used to explore primary brain function.

The cost-effectiveness analysis of laparoscopic treatment of ectopic pregnancy: a single-center review of a five-year experience

PURPOSE

The aim of this study was to investigate the cost-effectiveness of laparoscopic treatment for ectopic pregnancy by comparing the medical expenses and time of hospitalization of laparoscopic and open surgery for ectopic pregnancy in partial area of Shanghai, China.

MATERIALS AND METHODS

Clinical data of 762 cases with ectopic pregnancy undergoing surgical treatment (307 cases for laparoscopic surgery and 455 cases for open surgery) were analyzed retrospectively. The clinical information including the medical expenses and time of hospitalization was compared. The patients were divided into three groups according to the treatments of different lesions (lesions resection, conservative laparotomy, and exploration group) and were analyzed.

RESULTS

The total hospitalization expenses and the top three single costs including surgery, exams, and medicine expenses were higher in laparoscopic group than in open surgery group. There was no significant difference between the two groups on the total time of hospitalization. The hospital days of preoperation were higher but the postoperative hospital days were lower in laparoscopic group than in open surgery group. Compared with the open surgery treatment, the hospitalization expenses of laparoscopic treatment for ectopic pregnancy increased. There was no significant difference on the total hospitalization days.

CONCLUSION

The preoperative waiting period of inpatients increased and the post-operative hospital days reduced in laparoscopic group.

Pathway enrichment analysis of human osteosarcoma U-2 OS bone cells expose to dexamethasone

OBJECTIVE

Osteosarcoma is the second highest cause of cancer-related death in children, mainly due to development of often fatal metastasis, usually in the lungs. Glucocorticoids play an important role in the treatment of a number of inflammatory diseases and immune diseases. The objective of this study was to explore the molecular mechanism of osteosarcoma in response to dexamethasone (DEX, a kind of synthetic glucocorticoid), with a view to obtain information on the pathways activated by DEX.

MATERIALS AND METHODS

By using the GSE6711 Affymetrix microarray data accessible from Gene Expression Omnibus database, we first identified the differentially expressed genes (DEGs) among different time course treatment with dexamethasone of each isoform, and the DEGs among cells expressing different GR isoforms, followed by the pathway enrichment analysis of the DEGs.

RESULTS

The results indicated that DEX could inhibit osteosarcoma cell proliferation and promote osteosarcoma cell apoptosis through induction of lots of related genes expression at the transcription level.

CONCLUSIONS

Our data provide a comprehensive bioinformatics analysis of pathways which may be involved in the response to glucocorticoids.

NKG2D blockade attenuated cardiac allograft vasculopathy in a mouse model of cardiac transplantation

A previous paper has reported that blockade of NKG2D was effective in protecting allograft in murine models of cardiac transplantation, but the mechanism of NKG2D blockade on attenuated cardiac allograft vasculopathy (CAV) was still unknown. In our current study, we found that wild-type recipients treated with anti-NKG2D monoclonal antibody (mAb) plus cytotoxic T lymphocyte antigen (CTLA)-4-immunoglobulin (I)g showed prolonged allograft survivals (>90 days, P < 0·001) significantly and attenuated CAV. These in-vivo results correlated with reduced alloantibody production, low expression of interleukin (IL)-17 and IL-6, while infiltration of regulatory T cells increased. IL-6 administration induced shorter allograft survival and higher CAV grade in CTLA-4-Ig plus anti-NKG2D mAb-treated recipients, whereas IL-17 had no significant effect on allograft survival and CAV grade in CTLA-4-Ig plus anti-NKG2D mAb-treated recipients. Furthermore, the prolonged allograft survival induced by NKG2D blockade was abrogated partially with depletion of regulatory T cells. In conclusion, blockade of NKG2D combined with CTLA-4-Ig attenuated CAV and this effect was associated with lower alloantibody production, inhibited IL-6 expression and enhanced expansion of regulatory T cells.

The huntingtin N17 domain is a multifunctional CRM1 and Ran-dependent nuclear and cilial export signal

The first 17 amino acids of Huntington's disease (HD) protein, huntingtin, comprise an amphipathic alpha-helical domain that can target huntingtin to the endoplasmic reticulum (ER). N17 is phosphorylated at two serines, shown to be important for disease development in genetic mouse models, and shown to be modified by agents that reverse the disease phenotype in an HD mouse model. Here, we show that the hydrophobic face of N17 comprises a consensus CRM1/exportin-dependent nuclear export signal, and that this nuclear export activity can be affected by serine phospho-mimetic mutants. We define the precise residues that comprise this nuclear export sequence (NES) as well as the interaction of the NES, but not phospho-mimetic mutants, with the CRM1 nuclear export factor. We show that the nuclear localization of huntingtin depends upon the RanGTP/GDP gradient, and that N17 phosphorylation can also distinguish localization of endogenous huntingtin between the basal body and stalk of the primary cilium. We present a mechanism and multifunctional role for N17 in which phosphorylation of N17 not only releases huntingtin from the ER to allow nuclear entry, but also prevents nuclear export during a transient stress response event to increase the levels of nuclear huntingtin and to regulate huntingtin access to the primary cilium. Thus, N17 is a master localization signal of huntingtin that can mediate huntingtin localization between the cytoplasm, nucleus and primary cilium. This localization can be regulated by signaling, and is misregulated in HD.

Pollen limitation and Allee effect related to population size and sex ratio in the endangered Ottelia acuminata (Hydrocharitaceae): implications for conservation and reintroduction

Small populations may suffer more severe pollen limitation and result in Allee effects. Sex ratio may also affect pollination and reproduction success in dioecious species, which is always overlooked when performing conservation and reintroduction tasks. In this study, we investigated whether and how population size and sex ratio affected pollen limitation and reproduction in the endangered Ottelia acuminata, a dioecious submerged species. We established experimental plots with increasing population size and male sex ratio. We observed insect visitation, estimated pollen limitation by hand-pollinations and counted fruit set and seed production per fruit. Fruit set and seed production decreased significantly in small populations due to pollinator scarcity and thus suffered more severe pollen limitation. Although frequently visited, female-biased larger populations also suffered severe pollen limitation due to few effective visits and insufficient pollen availability. Rising male ratio enhanced pollination service and hence reproduction. Unexpectedly, pollinator preferences did not cause reduced reproduction in male-biased populations because of high pollen availability. However, reproductive outputs showed more variability in severe male-biased populations. Our results revealed two component Allee effects in fruit set and seed production, mediated by pollen limitation in O. acuminata. Moreover, reproduction decreased significantly in larger female-biased populations, increasing the risk of an Allee effect.

Characterization of diverse antimicrobial peptides in skin secretions of Chungan torrent frog Amolops chunganensis

We have cloned, synthesized, and characterized 11 novel antimicrobial peptides from a skin derived cDNA library of the Chungan torrent frog, Amolops chunganensis. Seven of the 11 antimicrobial peptides were present in authentic A. chunganensis skin secretions. Sequence analysis indicated that the 11 peptides belonged to the temporin, esculentin-2, palustrin-2, brevinin-1, and brevinin-2 families. The peptides displayed potent antimicrobial activities against several strains of microorganisms. One peptide, brevinin-1CG5, demonstrated antimicrobial activity against all tested Gram-positive and Gram-negative bacteria and fungi, and showed high antimicrobial potency (MIC=0.6 μM) against Gram-positive bacterium Rhodococcus rhodochrous. Some peptides also demonstrated weak hemolytic activity against human erythrocytes in vitro. Phylogenetic analysis based on the amino acid sequences of brevinin-1, brevinin-2, and esculentin-2 peptides from family Ranidae confirmed that the current taxonomic status of A. chunganensis is correct.

Anti-interleukin-12/23p40 antibody attenuates chronic rejection of cardiac allografts partly via inhibition γδT cells

In our previous study, we showed that treatment with an anti-interleukin (IL)-12/23p40 antibody inhibits acute cardiac allograft rejection via inhibiting production of interferon (IFN)-γ and IL-17a. However, the impact of this antagonistic anti-p40 antibody on chronic cardiac rejection was unclear. Hearts of B6.C-H2bm12/KhEg mice were transplanted into major histocompatibility complex (MHC) class II-mismatched C57Bl/6J mice (wild-type, γδTCR (-/-) and IL-17(-/-) ), which is an established murine model of chronic allograft rejection without immunosuppression. The mice were treated with control immunoglobulin (Ig)G or 200 µg anti-p40 monoclonal antibody on post-operative days, respectively. Abdominal palpation and echocardiography were used to monitor graft survival. The mice administered with anti-p40 antibody showed a significant promotion in graft survival (median survival time >100 days), and histological analyses revealed that cardiac allograft rejection was attenuated. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunofluorescence analyses demonstrated that anti-p40 antibody down-regulated the level of ingraft cytokine and chemokine expression (IL-6, IFN-γ, IL-17a, CCL2 and CCL20). Flow cytometry analyses showed that γδ T cells are an important ingraft source of IFN-γ and IL-17a and inhibit the production of inflammation cytokine by anti-p40 antibody. Compared with the wild-type group, the graft survival time in the γδ T cell receptor(-/-) and IL-17(-/-) mice was prolonged significantly. Therefore we propose that, in the chronic allograft rejection model, treatment with anti-p40 antibody prolongs graft survival possibly by reducing the amount of reactive inflammatory cells, especially γδ T cells.

Chronic morphine exposure affects contrast response functions of V1 neurons in cats

Opiates disrupt neural functions in many brain areas, including visual cortex. Previous studies have indicated substantial changes of many neuronal response properties induced by chronic morphine exposure in the visual information processing system. However, it remains unclear whether neuronal contrast coding is also affected. To investigate this issue, we measured the contrast response functions (CRFs) of V1 neurons in chronic morphine-treated and saline-treated cats by using extra-cellular single-unit recording techniques. Our results indicated significantly lower contrast sensitivity in morphine-treated cats than in saline-treated cats and V1 neurons in morphine-treated cats exhibited enhanced maximum visual responses, higher baseline responses and lower signal-to-noise ratios compared with saline-treated cats. These findings provide some neurobiological evidence for the morphine-mediated degenerations of the visual cortex, which could underlie the opiate-induced deficits in visual function.

SU-E-J-158: A Prototype of a Real-Time Respiratory Motion Monitoring System Using Microsoft Kinect Sensor

PURPOSE

To investigate the feasibility of a low-cost respiratory motion monitoring system based on the Microsoft Xbox Kinect sensor.

METHODS

We improved Kinect's inherent depth resolution from 1 cm to 1 mm via a motion magnification system. Using the Kinect software development kit, we programmed the Kinect to capture depth images and determine the average depth over a thoracic region of interest, viewed almost parallel to the subject's surface. Kinect respiratory traces (average depth vs time at a rate of 30 Hz) were acquired from four volunteers and compared with those simultaneously acquired using a commercially available strain gauge respiratory gating system.

RESULTS

The correlation coefficient (CC) between Kinect and strain gauge traces varied from 0.958 to 0.978, with a mean CC of 0.969. This strong correlation was also demonstrated by the joint probability distribution and visual inspection.

CONCLUSIONS

This work demonstrates the feasibility of using the Kinect for respiratory motion tracking. Traces are similar to those of a clinically used strain gauge system. The Kinect-based system provides a new and economical way to monitor respiratory motion.

Intermediate-conductance Ca(2+) -activated potassium and volume-sensitive chloride channels in endothelial progenitor cells from rat bone marrow mononuclear cells

AIM

Bone marrow endothelial progenitor cells (BMEPCs) are believed to be a promising cell source for regenerative medicine; however, their electrophysiology properties have not been fully clarified, which is important to the clinical application of BMEPCs. The current study was designed to determine the transmembrane ion currents and mRNA expression levels of related ion channel subunits in rat BMEPCs.

METHODS

Bone marrow mononuclear cells were isolated by density gradient separation and cultured in EPC medium. The transmembrane ion currents were determined using whole-cell patch-voltage clamp technique, and the levels of mRNA and protein expressions of functional ionic channels were measured using RT-PCR and western immunoblot analysis.

RESULTS

We observed two types of ionic currents in undifferentiated rat BMEPCs. One was Ca(2+) -activated potassium current (I(kca) ), which was seen in approx. 90% of cells when 1 μm Ca(2+) was employed in pipette solution, and it was predominantly inhibited by intermediate-conductance I(kca) inhibitor clotrimazole. The other one was volume-sensitive chloride current (I(cl) ), which was detected in 85.7% of cells when BMEPCs were subjected to K(+) -free hypotonic extracellular solution, whose currents could be inhibited by 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB). The corresponding ion channel genes and proteins, KCNN4 for I(kca) and Clcn3 for I(cl) , were confirmed by RT-PCR and western immunoblot analysis of BMEPCs.

CONCLUSION

Our results demonstrated for the first time that rat BMEPCs expressed intermediate-conductance Ca(2+) -activated potassium currents and volume-sensitive chloride currents, and corresponding genes and proteins of these two channels are KCNN4 and Clcn3 respectively.

Perceived parenting and risk for major depression in Chinese women

BACKGROUND

In Western countries, a history of major depression (MD) is associated with reports of received parenting that is low in warmth and caring and high in control and authoritarianism. Does a similar pattern exist in women in China?

METHOD

Received parenting was assessed by a shortened version of the Parental Bonding Instrument (PBI) in two groups of Han Chinese women: 1970 clinically ascertained cases with recurrent MD and 2597 matched controls. MD was assessed at personal interview.

RESULTS

Factor analysis of the PBI revealed three factors for both mothers and fathers: warmth, protectiveness, and authoritarianism. Lower warmth and protectiveness and higher authoritarianism from both mother and father were significantly associated with risk for recurrent MD. Parental warmth was positively correlated with parental protectiveness and negatively correlated with parental authoritarianism. When examined together, paternal warmth was more strongly associated with lowered risk for MD than maternal warmth. Furthermore, paternal protectiveness was negatively and maternal protectiveness positively associated with risk for MD.

CONCLUSIONS

Although the structure of received parenting is very similar in China and Western countries, the association with MD is not. High parental protectiveness is generally pathogenic in Western countries but protective in China, especially when received from the father. Our results suggest that cultural factors impact on patterns of parenting and their association with MD.

Behavioral plasticity in honey bees is associated with differences in brain microRNA transcriptome

Small, non-coding microRNAs (miRNAs) have been implicated in many biological processes, including the development of the nervous system. However, the roles of miRNAs in natural behavioral and neuronal plasticity are not well understood. To help address this we characterized the microRNA transcriptome in the adult worker honey bee head and investigated whether changes in microRNA expression levels in the brain are associated with division of labor among honey bees, a well-established model for socially regulated behavior. We determined that several miRNAs were downregulated in bees that specialize on brood care (nurses) relative to foragers. Additional experiments showed that this downregulation is dependent upon social context; it only occurred when nurse bees were in colonies that also contained foragers. Analyses of conservation patterns of brain-expressed miRNAs across Hymenoptera suggest a role for certain miRNAs in the evolution of the Aculeata, which includes all the eusocial hymenopteran species. Our results support the intriguing hypothesis that miRNAs are important regulators of social behavior at both developmental and evolutionary time scales.

Development of a low-cost magnetic microfluidic chip for circulating tumour cell capture

The authors have developed a novel fabrication process for a selective micro-magnetic activated cell sorting (MACS) chip based on ferromagnetic material encapsulated micropillars (FMEMs), which is technically simple and low cost. The FMEM produces a high field gradient to magnetically attract, capture and hold cells on its interface. System test simulations were carried out to predict the efficacy of target capture and verify that the actual magnetic particles behaviour agreed well with model predictions. To determine the ability of the novel microMACS chip to capture circulating tumour cells (CTCs), SW620 human colon cancer cells were used in an in vitro flow model system and were able to be captured with the efficiency of 72.8%. The obvious accumulation of CTCs at a certain location on the chip suggested shear stress events at the pillar boundary may influence efficacy, and should be considered in further optimisation efforts.

Ginsenoside-Rd improves outcome of acute ischaemic stroke - a randomized, double-blind, placebo-controlled, multicenter trial

BACKGROUND AND PURPOSE

 Ginsenoside-Rd is a receptor-operated calcium channel antagonist and has shown promise as a neuroprotectant in our phase II study. As an extended work, we sought to confirm its efficacy and safety of Ginsenoside-Rd in patients with acute ischaemic stroke.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial involving 390 patients with acute ischaemic stroke in a 3:1 ratio to receive a 14-day intravenous infusion of Ginsenoside-Rd or placebo within 72 h after the onset of stroke. Our primary end-point was the distribution of disability scores on the modified Rankin scale (mRs) at 90 days.

RESULTS

  The efficacy analysis was based on 386 patients (Ginsenoside-Rd group: 290; placebo group: 96). Ginsenoside-Rd significantly improved the overall distribution of scores on the mRs, as compared with the placebo (P = 0.02; odds ratios [OR], 1.74; 95% confidence interval [CI], 1.08-2.78). There were significant differences between the two groups when we categorized the scores into 0-1 vs. 2-5 (P = 0.01; OR, 2.32; 95% CI, 1.23-4.38; 66.8% vs. 53.1%). It also improved the National Institutes of Health Stroke Scale (NIHSS) at 15 days [P < 0.01; least squares mean (LSM), -0.77; 95% CI, -1.31 to -0.24]. Mortality and rates of adverse events were similar in the two groups.

CONCLUSIONS

  Ginsenoside-Rd improved the primary outcome of acute ischaemic stroke and had an acceptable adverse-event profile.