Dichotomy in the T-linear resistivity in hole-doped cuprates

From analysis of the in-plane resistivity ρ(ab)(T) of La(2-x)Sr(x)CuO(4), we show that normal state transport in overdoped cuprates can be delineated into two regimes in which the electrical resistivity varies approximately linearly with temperature. In the low-temperature limit, the T-linear resistivity extends over a very wide doping range, in marked contrast to expectations from conventional quantum critical scenarios. The coefficient of this T-linear resistivity scales with the superconducting transition temperature T(c), implying that the interaction causing this anomalous scattering is also associated with the superconducting pairing mechanism. At high temperatures, the coefficient of the T-linear resistivity is essentially doping independent beyond a critical doping p(crit)=0.19 at which the ratio of the two coefficients is maximal. Taking our cue from earlier thermodynamic and photoemission measurements, we conclude that the opening of the normal-state pseudogap at p(crit) is driven by the loss of coherence of anti-nodal quasi-particles at low temperatures.

Inclusion of the female condom in a male condom-only intervention in the sex industry in China: a cross-sectional analysis of pre- and post-intervention surveys in three study sites

OBJECTIVES

To describe female condom (FC) use, male condom (MC) use and overall levels of protected sex before, during and after FC education and promotion (using the original prototype FC) combined with MC promotion among female sex workers in three rural or small urban settings in southern China.

STUDY DESIGN

The 1-year FC intervention was conducted by local health workers through outreach to establishments where sex work is conducted. Three serial cross-sectional surveys were conducted in each study town before, during and after the intervention along with process documentation throughout the intervention period.

METHODS

Cross-sectional data from pre-intervention (baseline) and 6-month and 12-month post-intervention surveys from three study sites are used in a descriptive comparison of the context of the sex industry, outreach in two phases of intervention, and FC adoption after the intensive intervention phase in each site.

RESULTS

Approximately 75-80% of eligible women working in sex establishments, varying from 74 to 155 participants for each survey, were recruited from three study sites. After introduction and promotion of the FC along with the MC during the community public health intervention, between one-fifth and one-half of the study participants had tried the FC in the three study sites by the time of the 6-month and 12-month cross-sectional surveys. Among them, 10-30% had used the FC more than once. FC awareness increased following the intervention with much less variation across the three study sites. At baseline, 31-54% of participants across the three sites reported 100% protected sex in the last 30 days with all types of partners. At one of the sites with relatively low MC use before the intervention, the proportion of women reporting 100% protected sex in the last 30 days increased by 15%, and the proportion reporting nil protected sex in the last 30 days decreased by 13% between baseline and 12-month post-intervention surveys. More complex profiles of FC and MC use and protected sex were shown at the other two study sites, where a higher level of protection had been reached before the project started.

CONCLUSIONS

Different levels of FC adoption were identified after the 1-year FC promotion intervention through outreach to sex establishments. The input, output and outcomes of the intervention may be associated with women's demographic and risk characteristics, the local capacities of intervention staff, and other contextual factors. Further analysis of these factors will help establish the role of the FC in increasing protected sex, and provide insight into how to achieve greater FC use.

Meta-analysis of dermatological toxicities associated with sorafenib

A meta-analysis was performed to determine the type, incidence and risks of dermatological toxicities associated with the multikinase inhibitor sorafenib. A literature search was performed using the electronic databases PubMed and EMBASE, and conference abstracts published by the American Society of Clinical Oncology. Eligible studies included prospective phase II or III clinical trials, and expanded-access programmes (i.e. outside a clinical trial) of patients with solid tumours assigned sorafenib at a starting dose of 400 mg twice daily. The overall incidences and risk ratios of dermatological toxicities associated with sorafenib were analysed. For patients assigned sorafenib, the overall incidence of all-grade rash/desquamation was 35.4% (95% CI 0.29-0.43), hand-foot skin reaction (HFSR) 39.0% (95% CI 0.32-0.47), alopecia 25.5% (95% CI 0.18-0.35), pruritus 14.0% (95% CI 0.10-0.20) and dry skin 14.1% (95% CI 0.10-0.20). High-grade rash/desquamation events occurred in 5.0% (95% CI 0.04-0.07), HFSR in 9.0% (95% CI 0.082-0.098), alopecia in 4/1793, pruritus in 2/1265 and dry skin in 0/1689 of patients assigned sorafenib. Meta-analysis of risk ratio showed that sorafenib was associated with a significantly increased risk of rash/desquamation [risk ratio (RR) 2.73; 95% CI 1.66-4.49)], HFSR (RR 7.50; 95% CI 3.90-14.40) and alopecia (RR 7.55; 95% CI 5.26-10.84) in patients with solid tumours, but risk of pruritus (RR 1.80; 95% CI 0.77-4.22) or dry skin (RR 2.18; 95% CI 0.88-5.40) was not increased. In conclusion, the most frequent dermatological toxicities associated with sorafenib were HFSR, rash/desquamation, alopecia, pruritus and dry skin. There was a significantly increased risk of HFSR, rash/desquamation and alopecia with sorafenib compared with placebo. Skin toxicities were mainly mild or moderate in severity. Appropriate prevention and management are recommended.

C10ORF97 is a novel tumor-suppressor gene of non-small-cell lung cancer and a functional variant of this gene increases the risk of non-small-cell lung cancer

In an earlier study we showed that C10ORF97 (chromosome-10, open reading frame-97) was expressed in almost all of the tissues and cell lines tested, and that it inhibited the growth of seven tumor cell lines, including two lung carcinoma cell lines (A549 and PG). Here, we show that C10ORF97 is downregulated in non-small-cell lung cancer (NSCLC) tissue compared with normal lung tissue. Overexpression of C10ORF97 significantly suppressed human lung carcinoma A549 cell growth (proliferation and anchorage-independent growth in soft agar) and motility (migration and adhesion). This tumor-suppressive function of C10ORF97 was also verified in vivo. We further found that C10ORF97 caused G(1) arrest of A549 cells and modulated the expression level of several cell-cycle regulators (such as CDK2, cyclin-E and p27). These effects of C10ORF97 were mediated by physical association between C10ORF97 and Jun-activating domain-binding protein-1 (JAB1), and blocking of JAB1-mediated translocation of p27 from the nucleus to the cytoplasm. Together, these results indicated that C10ORF97 functions as a novel tumor suppressor by modulating several key G(1)/S-regulatory proteins by interacting with JAB1. These findings led us to hypothesize that a single-nucleotide polymorphism (SNP) in the C10ORF97 gene that affects its expression might be associated with susceptibility to NSCLC. SNP216 C>T (rs2297882) in the C10ORF97 Kozak sequence was identified, and allele T of SNP216 suppressed C10ORF97 expression in vitro and in vivo. Furthermore, the TT genotype of SNP216 was associated with an increased risk of NSCLC (adjusted odds ratio=1.73 (95% confidence interval: 1.33-2.25), P=4.6 × 10(-5)). These data indicated that C10ORF97 is a tumor suppressor of NSCLC progression and C10ORF97-SNP216 may serve as a predictor of NSCLC.

Characterization of epidermal growth factor receptor mutations in non-small-cell lung cancer patients of African-American ancestry

Epidermal growth factor receptor (EGFR) mutations are predictive markers for response to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in non-small-cell lung cancer (NSCLC). The most common mutations, exon 19 short deletions and exon 20 point mutation (L858R), activate the tyrosine kinase and confer sensitivity to EGFR-TKIs. However, the function and sensitivity of rare mutations to EGFR-TKIs are unknown. In this study, we found five EGFR mutations out of 16 patients with NSCLC of African-American descent. The frequency of such mutations in this patient population appears to be significantly higher than previously reported. Two of them (N771GY and A767-V769dup) are rare insertion mutations located in exon 20. Using YFP-tagged EGFR mutants, we demonstrated that the mutations confer increased kinase activity, but no sensitivity to erlotinib at clinically available concentrations. In addition, we examined efficacy of PF00299804, an irreversible EGFR-TKI. Although the drug failed to show efficacy to T790M and S768N mutations, the exon 20 insertion mutations were sensitive to PF00299804. These data suggest that rare mutations in exon 20 are resistant to erlotinib but may be sensitive to irreversible inhibitors.

Site-specific hyperphosphorylation of pRb in HIV-induced neurotoxicity

HIV-Associated Neurocognitive Disorder (HAND) remains a serious complication of HIV infection, despite combined Anti-Retroviral Therapy (cART). Neuronal dysfunction and death are attributed to soluble factors released from activated and/or HIV-infected macrophages. Most of these factors affect the cell cycle machinery, determining cellular outcomes even in the absence of cell division. One of the earliest events in cell cycle activation is hyperphosphorylation of the retinoblastoma protein, pRb (ppRb). We and others have previously shown increased ppRb expression in the CNS of patients with HIV encephalitis (HIVE) and in neurons in an in vitro model of HIV-induced neurodegeneration. However, trophic factors also lead to an increase in neuronal ppRb with an absence of cell death, suggesting that, depending on the stimulus, hyperphosphorylation of pRb can have different outcomes on neuronal fate. pRb has multiple serines and threonines targeted for phosphorylation by distinct kinases, and we hypothesized that different stimuli may target separate sites for phosphorylation. Thus, to determine whether pRb is differentially phosphorylated in response to different stimuli and whether any of these sites is preferentially phosphorylated in association with HIV-induced neurotoxicity, we treated primary rat mixed cortical cultures with trophic factors, BDNF or RANTES, or with the neurotoxic factor, N-methyl-d-aspartate (NMDA), or with supernatants containing factors secreted by HIV-infected monocyte-derived macrophages (HIV-MDM), our in vitro model of HIV-induced neurodegeneration. We found that, while BDNF and RANTES phosphorylated serine807/811 and serine608 in vitro, treatment with HIV-MDM did not, even though these trophic factors are components of HIV-MDM. Rather, HIV-MDM targets a specific phosphorylation site, serine795, of pRb for phosphorylation in vitro and this ppRb isoform is also increased in HIV-infected brains in vivo. Further, overexpression of a nonphosphorylatable pRb (ppRb S795A) attenuated HIV-MDM-induced neurotoxicity. These findings indicate that HIV-infection in the brain is associated with site-specific hyperphosphorylation of pRb at serine795, which is not induced by other tested stimuli, and that this phosphorylation contributes to neuronal death in this disease, demonstrating that specific pRb sites are differentially targeted and may have diverse impacts on the viability of post-mitotic neurons.

A novel family of RGD-containing disintegrins (Tablysin-15) from the salivary gland of the horsefly Tabanus yao targets αIIbβ3 or αVβ3 and inhibits platelet aggregation and angiogenesis

A novel family of RGD-containing molecules (Tablysin-15) has been molecularly characterised from the salivary gland of the haematophagous horsefly Tabanus yao. Tablysin-15 does not share primary sequence homology to any disintegrin discovered so far, and displays an RGD motif in the N-terminus of the molecule. It is also distinct from disintegrins from Viperidae since its mature form is not released from a metalloproteinase precursor. Tablysin-15 exhibits high affinity binding for platelet αIIbβ3 and endothelial cell αVβ3 integrins, but not for α5β1 or α2β1. Accordingly, it blocks endothelial cell adhesion to vitronectin (IC50 ~1 nM) and marginally to fibronectin (IC50 ~1 μM), but not to collagen. It also inhibits fibroblast growth factor (FGF)-induced endothelial cell proliferation, and attenuates tube formation in vitro. In platelets, Tablysin-15 inhibits aggregation induced by collagen, ADP and convulxin, and prevents static platelet adhesion to immobilised fibrinogen. In addition, solid-phase assays and flow cytometry demonstrates that αIIbβ3 binds to Tablysin-15. Moreover, immobilised Tablysin-15 supports platelet adhesion by a mechanism which was blocked by anti-integrin αIIbβ3 monoclonal antibody (e.g. abciximab) or by EDTA. Furthermore, Tablysin-15 dose-dependently attenuates thrombus formation to collagen under flow. Consistent with these findings, Tablysin-15 displays antithrombotic properties in vivo suggesting that it is a useful tool to block αIIbβ3, or as a prototype to develop antithrombotics. The RGD motif in the unique sequence of Tablysin-15 represents a novel template for studying the structure-function relationship of the disintegrin family of inhibitors.

A clinical case-control study on the association between mannose-binding lectin and susceptibility to HIV-1 infection among northern Han Chinese population

Mannose-binding lectin (MBL) is a key molecule of the innate immune system and a competent to bind carbohydrates of a variety of microorganisms, resulting in complement activation and opsonophagocytosis against various pathogens. However, there is no systemic investigation on the MBL's role in innate immune responses against HIV-1 infection among northern Han Chinese. This study investigated the association between MBL and HIV-1 infection susceptibility among northern Han Chinese. A total of 91 HIV-1 infected patients and 91 HIV-1 seronegative healthy individuals were recruited. Six polymorphisms of MBL2 gene were genotyped by pyrosequencing. The quantitative measurement of serum MBL concentration and MBL complex activity were performed by ELISA. The CD4+ T-cell counts were determined by flow cytometry. The plasma viral loads of 91 HIV-1 infected patients were determined by bDNA method. The results show that there is an association between MBL and HIV-1 infection susceptibility among northern Han Chinese. The individuals with B variant, low serum MBL concentration and low MBL complex activity are more susceptible to HIV-1 infection.

Predicting microstructures in polymer blends under two-step quench in two-dimensional space

The formation of nanostructures during two-step quench in binary polymer systems having various types of liquid miscibility gaps are investigated systematically via computer simulations using the phase field method. Coupled liquid spinodal decomposition and fluid flow processes are considered by solving simultaneously the Cahn-Hilliard and Navier-Stokes equations. Various interesting phenomena and morphological patterns are predicted. It is found that the primary microstructures developed at the first quench and isothermal holding temperature greatly affect the secondary microstructures developed during the second quench and isothermal holding. Depending on the morphology and scale of the primary microstructure, either multicore and multishell or unicore and unishell structures are predicted. The breakup of annuluses in a core-shell structure in two dimensions is analyzed. The effects of viscosity on the formation of core-shell structure and on the growth and coarsening behaviors of bimodal droplets produced by the two-step quench in systems are also investigated.

The 3Ns chromosome of Psathyrostachys huashanica carries the gene(s) underlying wheat stripe rust resistance

Stripe rust (Puccinia striiformis tritici (Pst)) is one of the most destructive diseases of wheat in the world. Exploiting and utilizing stripe rust resistance genes of wild species has become an essential strategy for resistance breeding. Psathyrostachyshuashanica Keng ex Kuo is a wild species in Triticeae that has been used for wheat improvement because of its high resistance or immunity to stripe rust. In this study, 9 wheat-P. huashanica addition lines were characterized by Giemsa C-banding, genomic in situ hybridization (GISH), and disease resistance evaluation. Giemsa C-banding and GISH demonstrated that lines 163-5, 165-1, 183-5, 240-3, and 240-4 are P. huashanica 3Ns chromosome monosomic addition lines; lines 183-1 and 183-20 are P. huashanica 3Ns chromosome disomic addition lines; line 165-20 is a P. huashanica 3Ns and 4Ns chromosomes double disomic addition line, and line 219-1 is a P. huashanica 1Ns and 3Ns/5A chromosomes double disomic addition-substitution line. All these addition lines with P. huashanica 3Ns chromosome(s) expressed high resistance or immunity to stripe rust. By comparing the series of wheat-P. huashanica chromosome addition lines, we concluded that the P. huashanica 3Ns chromosome carries the gene(s) for resistance or immunity to stripe rust. These addition lines can be used as a donor source of novel stripe rust resistance to wheat breeding programs.

Electrogenerated chemiluminescence from carbon dots

We report an interesting property of carbon dots: they emit light under charge injection. We synthesized carbon dots in diameter about 20 nm using wet chemistry methods. The photoluminescence quantum efficiency of the carbon dots dissolved in water was about 11%. We observed strong electrogenerated chemiluminescence (ECL) from the sample. This observation of ECL from carbon dots indicates that they could be a good candidate material for carbon-based electroluminescent devices.

Tailoring a two-dimensional electron gas at the LaAlO3/SrTiO3 (001) interface by epitaxial strain

Recently a metallic state was discovered at the interface between insulating oxides, most notably LaAlO3 and SrTiO3. Properties of this two-dimensional electron gas (2DEG) have attracted significant interest due to its potential applications in nanoelectronics. Control over this carrier density and mobility of the 2DEG is essential for applications of these unique systems, and may be achieved by epitaxial strain. However, despite the rich nature of strain effects on oxide materials properties, such as ferroelectricity, magnetism, and superconductivity, the relationship between the strain and electrical properties of the 2DEG at the LaAlO3/SrTiO3 heterointerface remains largely unexplored. Here, we use different lattice constant single-crystal substrates to produce LaAlO3/SrTiO3 interfaces with controlled levels of biaxial epitaxial strain. We have found that tensile-strained SrTiO3 destroys the conducting 2DEG, while compressively strained SrTiO3 retains the 2DEG, but with a carrier concentration reduced in comparison to the unstrained LaAlO3/SrTiO3 interface. We have also found that the critical LaAlO3 overlayer thickness for 2DEG formation increases with SrTiO3 compressive strain. Our first-principles calculations suggest that a strain-induced electric polarization in the SrTiO3 layer is responsible for this behavior. The polarization is directed away from the interface and hence creates a negative polarization charge opposing that of the polar LaAlO3 layer. This behavior both increases the critical thickness of the LaAlO3 layer, and reduces carrier concentration above the critical thickness, in agreement with our experimental results. Our findings suggest that epitaxial strain can be used to tailor 2DEGs properties of the LaAlO3/SrTiO3 heterointerface.

Msx1 mutations: how do they cause tooth agenesis?

Mutations in the transcription factors PAX9 and MSX1 cause selective tooth agenesis in humans. In tooth bud mesenchyme of mice, both proteins are required for the expression of Bmp4, which is the key signaling factor for progression to the next step of tooth development. We have previously shown that Pax9 can transactivate a 2.4-kb Bmp4 promoter construct, and that most tooth-agenesis-causing PAX9 mutations impair DNA binding and Bmp4 promoter activation. We also found that Msx1 by itself represses transcription from this proximal Bmp4 promoter, and that, in combination with Pax9, it acts as a potentiator of Pax9-induced Bmp4 transactivation. This synergism of Msx1 with Pax9 is significant, because it is currently the only documented mechanism for Msx1-mediated activation of Bmp4. In this study, we investigated whether the 5 known tooth-agenesis-causing MSX1 missense mutations disrupt this Pax9-potentiation effect, or if they lead to deficiencies in protein stability, protein-protein interactions, nuclear translocation, and DNA-binding. We found that none of the studied molecular mechanisms yielded a satisfactory explanation for the pathogenic effects of the Msx1 mutations, calling for an entirely different approach to the investigation of this step of odontogenesis on the molecular level.

MEMS Materials and Fabrication Technology on Large Areas: The Example of an X-ray Imager

Micromachining has potential applications for large area image sensors and displays, but conventional MEMS technology, based on crystalline silicon wafers cannot be used. Instead, large area devices use deposited films on glass substrates. This presents many challenges for MEMS, both as regards materials for micro-machined structures and the integration with large area electronic devices. We are exploring the novel thick photoresist SU-8, as well as plating techniques for the fabrication of large area MEMS. As an example of its application, we have applied this MEMS technology to improve the performance of an amorphous silicon based image sensor array. SU-8 is explored as the structural material for the X-ray conversion screen and as a thick interlayer dielectric for the thin film readout electronics of the imager.