Slater Insulator in Iridate Perovskites with Strong Spin-Orbit Coupling

The perovskite SrIrO_{3} is an exotic narrow-band metal owing to a confluence of the strengths of the spin-orbit coupling (SOC) and the electron-electron correlations. It has been proposed that topological and magnetic insulating phases can be achieved by tuning the SOC, Hubbard interactions, and/or lattice symmetry. Here, we report that the substitution of nonmagnetic, isovalent Sn^{4+} for Ir^{4+} in the SrIr_{1-x}Sn_{x}O_{3} perovskites synthesized under high pressure leads to a metal-insulator transition to an antiferromagnetic (AF) phase at T_{N}≥225  K. The continuous change of the cell volume as detected by x-ray diffraction and the λ-shape transition of the specific heat on cooling through T_{N} demonstrate that the metal-insulator transition is of second order. Neutron powder diffraction results indicate that the Sn substitution enlarges an octahedral-site distortion that reduces the SOC relative to the spin-spin exchange interaction and results in the type-G AF spin ordering below T_{N}. Measurement of high-temperature magnetic susceptibility shows the evolution of magnetic coupling in the paramagnetic phase typical of weak itinerant-electron magnetism in the Sn-substituted samples. A reduced structural symmetry in the magnetically ordered phase leads to an electron gap opening at the Brillouin zone boundary below T_{N} in the same way as proposed by Slater.

Novel mutations in quinolone resistance-determining regions of gyrA, gyrB, parC and parE in Shigella flexneri clinical isolates from eastern Chinese populations between 2001 and 2011

The aim of this study was to evaluate the prevalence of fluoroquinolone resistance and mechanisms of selected fluoroquinolone resistance in Shigella flexneri isolates. A total of 624 S. flexneri strains isolated between 2001 and 2011 in Jiangsu Province of China were analysed for their fluoroquinolone susceptibility. The quinolone resistance-determining region of gyrA, gyrB, parC and parE were amplified and sequenced. In general, 90.5 % of S. flexneri exhibited resistance to nalidixic acid. The mean norfloxacin resistance rate was 22.4 % during the 11 years from 2001 to 2011 (6.4 % from 2001 to 2005 and 36.8 % from 2006 to 2011). Sequencing of gyrA, gyrB, parC and parE genes of all S. flexneri isolates showed that the mutation rate was as high as 93.9 %. In addition, 91.8 % and 92.3 % of S. flexneri harboured mutations in gyrA and parC, respectively. About 35.2 % of S. flexneri isolates susceptible to nalidixic acid contained mutations. Meanwhile, mutations were detected in 91.2 % of norfloxacin-susceptible strains, and almost all S. flexneri isolates resistant to fluoroquinolone contained mutations. To the best of our knowledge, this is the first study reporting the occurrence of point mutations Asn57Lys and His80Pro in gyrA and Ala85Thr, Asp111His and Ser129Pro in parC. Emerging fluoroquinolone resistance with a significantly high mutation rate of the gyrA and parC genes in S. flexneri in Jiangsu Province deserves attention, and monitoring antibiotic susceptibility is important for the effective management of S. flexneri infections.

Quasi-One-Dimensional Metal-Insulator Transitions in Compound Semiconductor Surfaces

Existing examples of Peierls-type 1D systems on surfaces involve depositing metallic overlayers on semiconducting substrates, in particular, at step edges. Here we propose a new class of Peierls system on the (101[over ¯]0) surface of metal-anion wurtzite semiconductors. When the anions are bonded to hydrogen or lithium atoms, we obtain rows of threefold coordinated metal atoms that act as one-atom-wide metallic structures. First-principles calculations show that the surface is metallic, and below a certain critical temperature the surface will condense to a semiconducting state. The idea of surface scaffolding is introduced in which the rows are constrained to move along simple up-down and/or sideways displacements, mirroring the paradigm envisioned in Peierls's description. We predict that this type of insulating state should be visible in the partially hydrogenated (101[over ¯]0) surface of many wurtzite compounds.

Cotransport of graphene oxide and Cu(II) through saturated porous media

This study examines the cotransport of graphene oxide (GO) and Cu in porous media. The impacts of GO concentration and ion strength (IS) on Cu transport in laboratory packed columns were investigated. The results indicated that GO had fairly high mobility at a IS of 1mM, and could serve as an effective carrier of Cu(II). The facilitated transport was found to increase with increasing concentration of GO (CGO). The peak effluent concentration (C/C0)max of Cu was 0.57 at CGO of 120mg/L and IS=1mM and 0.13 at 40mg/L and IS=1mM. The Cu appears to be irreversibly adsorbed by the sand because no Cu appeared in the effluent in the absence of GO. However, the GO-facilitated Cu transport was reduced as the IS increased from 1 to 1000mM. In fact, the facilitated transport was zero percent at an IS of 1000mM. Particle size analysis, Zeta potential measurements and DLVO calculations demonstrated that higher IS values made the GO became unstable and it flocculated and attached to the sand. We also fed GO into the column pre-equilibrated by Cu as sequential elution experiments and found that the later introduced GO can complex the pre-adsorbed Cu from the sand surface because GO has a higher adsorption affinity for Cu. An advection-dispersion-retention numerical model was able to describe the Cu and GO transport in the column. Our work provides useful insights into fate, transport and risk assessment of heavy metal contaminants in the presence of engineered nanoparticles.

ID: 135: SINGLE CELL GENE EXPRESSION STUDIES IN LUPUS MONOCYTES REVEAL A UNIQUE ANTII-INFLAMMATORY NON-CLASSICAL MONOCYTE POPULATION ASSOCIATED WITH CLINICAL QUIESCENCE

Background

Our previous studies have shown that different cell types from the same blood sample demonstrate diverse gene expression parameters. In follow up work, it seems that this diversity extends to cells of the same type from the same blood sample. In this study, we examine single cell gene expression in SLE patient monocytes and determine correlations with clinical features.

Methods

CD14++CD16− classical monocytes (CLs) and CD14dimCD16+ non-classical monocytes (NCLs) from SLE patients were purified by magnetic separation. The Fluidigm single cell capture and pre-amplification system was used for single cell capture and target gene pre-amplification. Fluidigm Biomark system (Rt-PCR system) was used to quantify expression of 87 monocyte-related genes. IFN-induced genes in monocytes were identified by culturing monocytes isolated from whole blood of healthy controls with or without IFN-α. Genes significant up-regulated by IFN were identified as IFN-induced genes in current study. An individual cell IFN score was given based upon the sum of expression of IFN-induced genes.

Results

Both CLs and NCLs demonstrated a wide range of expression of IFN-induced genes, and NCL monocytes had higher IFN scores than CL monocytes. Using unsupervised hierarchical clustering, we found four gene sets that clustered monocytes functionally. These included an IFN-induced gene set, two inflammatory gene sets, and one immunosuppressive gene set. Interestingly, we could define a large subset of NCL monocytes with upregulation of suppressive transcripts (including TGF-β and PDL1) and IFN-induced transcripts were also upregulated, while the two inflammatory gene sets were down-regulated. These cells were highly over-represented in a patient with inactive disease who was on immunosuppressants at the time of blood draw. The proportion of anti-inflammatory gene set expressing NCLs was inversely correlated with anti-dsDNA titers (rho=−0.77, p=0.0051) and positively correlated with C3 complement (rho=0.68, p=0.030) in the SLE patient group, suggesting that these cells are also associated with serological quiescence.

Conclusion

Using single cell gene expression, we have identified a unique population of NCL monocytes in SLE patients with upregulation of a combination of anti-inflammatory and IFN-induced transcripts. These cells correspond with clinical and serological quiescence.

ID: 133: SINGLE CELL GENE EXPRESSION IN CLASSICAL MONOCYTES CORRELATES WITH TREATMENT RESPONSE TO TNF-ALPHA INHIBITION IN RHEUMATOID ARTHRITIS

Background

In management of rheumatoid arthritis (RA), initiating effective treatment as soon as possible within the so-called therapeutic “window of opportunity” is the strategy, and disease remission is a primary goal. Recent work from our group demonstrated that pre-treatment serum type I IFN-β/α activity ratio>1.3 can predict non-response to anti-TNF-alpha therapy in RA patients. The cellular mechanisms that underlie the IFN-β/α activity ratio that predicts response are not known. Effects of IFN on single immune cells and uncommon cell populations may be masked in whole blood or mixed cell populations.

Methods

To better understand the underpinnings of the pre-treatment IFN-β/α activity ratio, we used single cell expression analysis to investigate whether monocyte gene expression differs significantly between RA patients according to their pre-TNF-α inhibitor serum IFN-β/α activity ratio. Single classical (CL) and single non-classical (NCL) blood-derived monocytes were isolated from 15 seropositive RA subjects prior to biologic therapy. Total serum type I IFN, IFN-α, and IFN-β activity were measured using a functional reporter cell assay. Subjects were grouped by pre-TNF-α inhibitor serum IFN-β/α activity ratio into two groups, IFN-β/α>1.3 (n=6) and IFN-β/α<1.3 (n=9). Comparisons between groups were by Mann-Whitney. Hierarchical clustering of 87 target genes was done to determine if there were functional gene expression differences between groups.

Results

Hierarchical clustering revealed striking differences of expression of gene sets in CL monocytes between patients with IFN-β/α<1.3 and IFN-β/α>1.3, the groups which correspond to response/non-response to anti-TNF-α agents. This same clustering was not observed in NCL monocytes, and the differentiation between anti-TNF-α response patient groups was lost when hierarchical clustering was done on total monocytes (CL and NCL). Two major gene sets which differentiated subjects with IFN-β/α>1.3 (non-response to anti-TNF-α group) in CL monocytes included TLR and IFN pathway genes, cell surface markers and cytokines as follows: cluster 1 (TLR2, CD16, JAK1, IFI27, IL1A, and MAVS) and cluster 2 (GMCSF, TLR7, STAT2, ILT7, MYD88).

Conclusion

These within-cell expression patterns demonstrate biological differences in CL monocytes of RA patients with an IFN-β/α>1.3, the ratio of type I IFNs previously found to be predictive of non-response to anti-TNF-α therapy. Differentiation by gene expression among the response/non-response patient groups is lost when comparing gene expression in single NCL monocytes and single mixed population monocytes (CL and NCL), suggesting that further study of CL monocytes will likely illuminate molecular differences that determine treatment response to TNF-α inhibition in RA. This work will help to develop a more individualized approach to therapy in RA based upon the underlying biology of disease in a given patient.

Bovine leukemia virus infection in cattle of China: Association with reduced milk production and increased somatic cell score

The main objective of this study was to investigate the individual cow effect of bovine leukemia virus (BLV) infection on milk production and somatic cell score (SCS). The fluorescence resonance energy transfer (FRET) quantitative PCR established in this study and a commercial ELISA kit revealed that 49.1% of dairy cattle (964/1,963) from 6 provinces of China and 1.6% of beef cattle (22/1,390) from 15 provinces were BLV positive. In a detailed study of 105 cows, BLV was found most commonly in buffy coat samples that also had highest copy numbers (10(4.75±1.56) per mL); all cows negative for BLV in buffy coat samples were also negative in vaginal swab, milk, and fecal samples. Copy numbers of BLV were 10(2.90±0.42)/gram of feces, 10(0.83±0.62)/mL of milk, and 10(2.18±0.81) per vaginal swab. The BLV-positive cows had significantly lower milk production in the early (26.8 vs. 30.9kg) and middle stages of lactation (22.2 vs. 26.1kg) in animals with ≥4 parities than the BLV-negative cows; they also had significantly higher SCS in early and middle lactation stages (early=5.2 vs. 4.3; middle=4.9 vs. 3.9) in animals with ≥4 parities. Milk production and SCS did not significantly differ between the BLV-infected and -uninfected cows when they were in the late lactation stage or in animals with ≤3 parities. Taken together, our results indicate that BLV infections are widespread in the dairy farms of China. Vaginal secretions and feces may be involved in BLV transmission. A BLV infection may result in reduced milk yield and increased SCS in a parity and lactation stage-restricted manner.

FOXE1 polymorphisms and non-syndromic orofacial cleft susceptibility in a Chinese Han population

OBJECTIVE

FOXE1 plays an important role in craniofacial development. The aim of this study was to investigate associations between genetic variants of FOXE1 and risk of non-syndromic orofacial clefts in a Chinese population.

MATERIALS AND METHODS

Three potentially functional SNPs of FOXE1 (rs3758250 and rs907577 in the 5' upstream and rs7043516 in the 3'-UTR) were selected and their associations with non-syndromic orofacial cleft susceptibility were investigated in a case-control study from a Chinese population (602 cases and 605 controls). Genotyping was performed with double ligation and multiplex fluorescence PCR. Associations between the SNPs and risk of non-syndromic orofacial clefts and its subgroups were estimated from unconditional logistic regression analysis. Luciferase reporter assay was conducted to assess SNP function.

RESULTS

Overall, we did not find any of the individual SNP or haplotype was associated with NSOC susceptibility. Nevertheless, in stratified analysis, we found rs7043516, locating in the 3'-UTR of FOXE1, was associated with risk of cleft lip only. Further in vitro luciferase assay indicated that this SNP could contribute to differential binding ability with miRNA.

CONCLUSIONS

Taken together, this study showed that rs7043516 may be considered as a potentially susceptible marker of cleft lip only among Chinese Han populations.

Synthesis and Electrochemical Properties of Nitrogen-Doped Graphene (NG)/Nickle Oxide (NiO) Nanocomposite for Supercapacitor

A novel nitrogen-doped graphene (NG)/nickle oxide (NiO) nanocomposite was synthesized by a facile two-step method, where NiO particles were dispersed on the surface of NG. The NG/NiO nanocomposite is characterized by using field-emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Raman spectroscopy. The electrochemical properties of NG/NiO nanocomposite have been studied using cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) techniques. Compared with the nitrogen-doped graphene, the electrode prepared by NG/NiO nanocomposite has a mass specific capacitance of 342 F g(-1) at scan rate of 5 mV s(-1), which is much higher than that of nitrogen-doped graphene (NG). The galvanostatic charge/discharge results show this new kind nanocomposite has high specific capacitance with 320 F g(-1) in the range of 0.1-0.5 V at a current density of 1 A g(-1). The enhanced supercapacitive performance of NG/NiO nanocomposite suggesting its promising potential in supercapacitors.

Propofol: an anesthetic possessing neuroprotective effects

Propofol is a short-acting intravenous anaesthetic agent and widely used not only in operating rooms but also in the intensive care unit (ICU). Apart from its multiple anaesthetic advantages, the neuroprotective effect of propofol has been demonstrated in diverse models of neuronal injury. The effect of propofol results from activation of gamma-aminobutyric acid (GABA) receptor, modulation excitatory amino acid transmitter system and protecting brain cells against oxidative stress. Moreover, propofol is able to supress apoptosis and inflammation and to regulate neuroprotection-associated proteins or ion homeostasis to act its neuroprotective effects. This review focuses on the research progress of the neuroprotective effects of propofol and its mechanisms of action to date. The implications for possible use for the clinical setting are also discussed.

Transport of graphene oxide in saturated porous media: effect of cation composition in mixed Na-Ca electrolyte systems

The influence of cation composition in mixed Na-Ca electrolyte systems on the transport of graphene oxide particles in saturated porous media was studied. Column experiments were conducted to elucidate the transport behavior of GO by varied molar ratios of Ca2+/Na+ but of constant ionic strength (IS). The results show that retention of GO in sand column is strongly dependent on IS in the presence of Ca2+, featuring serious deposition rates (Rd) at the higher IS of 10 mM. The maximum Rd was 48.22% at 1 mM and 98.53% at 10 mM. However, there was no obvious difference in GO retention in solutions that only contained Na+ when the IS increased from 1 to 10 mM, and the Rd was 35.17% and 38.21% respectively. The molar ratio of Ca2+/Na+ in solution was much more influential in altering the particle retention behavior at the higher IS of 10 mM, compared with little influence at 1 mM. It was supposed that compression of diffuse double layers mainly controlled GO deposition under lower IS, while charge neutrality and metal (Ca2+) bridging played a significant role at the higher IS. A numerical advection-dispersion-retention model considering the combined processes of Langmuirian dynamics blocking and depth-dependent straining was successfully developed to simulate the transport process of GO through the sand column. Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy calculations were also performed to better understand the mechanisms of GO mobility. Coupling analysis of breakthrough experiments, DLVO theory and numerical modeling in this work provides insight into the mechanisms of GO transport in saturated porous media and is useful for reliable prediction of nanoparticle penetration through the vadose zone.

Effects of acrylonitrile on lymphocyte lipid rafts and RAS/RAF/MAPK/ERK signaling pathways

Acrylonitrile (ACN) is a widely used chemical in the production of plastics, resins, nitriles, acrylic fibers, and synthetic rubber. Previous epidemiological investigations and animal studies have confirmed that ACN affects the lymphocytes and spleen. However, the immune toxicity mechanism is unknown. Lipid rafts are cell membrane structures that are rich in cholesterol and involved in cell signal transduction. The B cell lymophoma-10 (Bcl10) protein is a joint protein that is important in lymphocyte development and signal pathways. This study was conducted to examine the in vitro effects of ACN. We separated lipid rafts, and analyzed Bcl10 protein and caveolin. Western blotting was used to detect mitogen-activated protein kinase (MAPK) and phosphorylated MAPK levels. The results indicated that with increasing ACN concentration, the total amount of Bcl10 remained stable, but was concentrated mainly in part 4 to part 11 in electrophoretic band district which is high density in gradient centrifugation. Caveolin-1 was evaluated as a lipid raft marker protein; caveolin-1 content and position were relatively unchanged. Western blotting showed that in a certain range, MAPK protein was secreted at a higher level. At some ACN exposure levels, MAPK protein secretion was significantly decreased compared to the control group (P < 0.05). These results indicate that ACN can cause immune toxicity by damaging lipid raft structures, causing Bcl10 protein and lipid raft separation and restraining Ras-Raf-MAPK-extracellular signal-regulated kinase signaling pathways.

Identification of early Al-responsive genes in rice bean (Vigna umbellata) roots provides new clues to molecular mechanisms of Al toxicity and tolerance

Significant secretion of citrate from root apex of rice bean (Vigna umbellata) is delayed by several hours under aluminium (Al) stress. However, the molecular basis of regulation of VuMATE1, a gene encoding an Al-activated citrate transporter, remains unclear. In this study, we used suppression subtractive hybridization together with reverse northern blot analysis and qRT-PCR to identify genes with altered transcript levels in the root apex after treatment with low (5 μm) or high (25 μm) concentration of AlCl(3) for a short time (4 h). We found that in addition to VuMATE1, 393 genes showed an early response to Al. Among functionally annotated genes, those related to 'metabolism and energy', 'signal transduction and transcription' and 'transport' was predominantly up-regulated, whereas those associated with 'protein translation, processing and degradation' was predominantly down-regulated. Comparative analysis of transcriptional profiles highlighted candidate genes associated with citrate secretion and revealed several new aspects of the molecular processes underlying Al toxicity and tolerance. Based on the data, it is proposed that metabolic changes represent adaptive mechanisms to Al stress, whereas inhibition of both cell elongation and cell division underlies Al-induced root growth inhibition.

Niv versus dropping vitrification in cryopreservation of human ovarian tissue

BACKGROUND

The containers for vitrification of tissues include cryovials, copper grids, Pasteur pipettes, the solid-surface method and etc. Recently the acupuncture needle was used to achieve better result in vitrification of human ovarian tissue.

OBJECTIVE

To determine if the needle immersed vitrification method (NIV) is a promising approach to vitrify the human ovarian tissue.

METHODS

Human ovarian biopsies from five patients were vitrified using NIV and Dropping vitrification. After 14 days of in vitro culture, the incidence of apoptotic primordial follicles from fresh and vitrified groups was assessed by TUNEL assay. 17β-estradiol (E2) and progesterone (P4) were detected in the media after culturing of vitrified and fresh ovarian tissues.

RESULTS

The incidence of apoptotic primordial follicles was significantly higher in the dropping vitrification group than in the NIV group (P < 0.05). E2 and P4 concentrations were significantly higher in NIV groups than in Dropping vitrification group (P < 0.05).

CONCLUSIONS

NIV was an appropriate method to vitrify ovarian tissue by improving the growth potential of frozen-warmed ovarian tissue in vitro culture.

Taurine improves functional and histological outcomes and reduces inflammation in traumatic brain injury

We investigated the effect of taurine on inflammatory cytokine expression, on astrocyte activity and cerebral edema and functional outcomes, following traumatic brain injury (TBI) in rats. 72 rats were randomly divided into sham, TBI and Taurine groups. Rats subjected to moderate lateral fluid percussion injury were injected intravenously with taurine (200mg/kg) or saline immediately after injury or daily for 7days. Functional outcome was evaluated using Modified Neurological Severity Score (mNSS). Glial fibrillary acidic protein (GFAP) of the brain was measured using immunofluorescence. Concentration of 23 cytokines and chemokines in the injured cortex at 1 and 7days after TBI was assessed by Luminex xMAP technology. The results showed that taurine significantly improved functional recovery except 1day, reduced accumulation of GFAP and water content in the penumbral region at 7days after TBI. Compared with the TBI group, taurine significantly suppressed growth-related oncogene (GRO/KC) and interleukin (IL)-1β levels while elevating the levels of regulated on activation, normal T cell expressed and secreted (RANTES) at 1day. And taurine markedly decreased the level of 17 cytokine: eotaxin, Granulocyte colony-stimulating factor (G-CSF), Granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-gamma (IFN-γ), IL-1α, IL-1β, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-13, IL-17, leptin, monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), vascular endothelial growth factor (VEGF), and only increased the level of MIP-1α in a week. The results suggest that taurine effectively mitigates the severity of brain damage in TBI by attenuating the increase of astrocyte activity and edema as well as pro-inflammatory cytokines.