Structural Evolution of Supercritical CO2 across the Frenkel Line

Here, we study structural properties of the supercritical carbon dioxide and discover the existence of persistent medium-range order correlations, which make supercritical carbon dioxide nonuniform and heterogeneous on an intermediate length scale. We report on the CO2 heterogeneity shell structure where, in the first shell, both carbon and oxygen atoms experience gas-like-type interactions with short-range order correlations while within the second shell, oxygen atoms essentially exhibit a liquid-like type of interactions due to localization of transverse-like phonon packets. Importantly, we highlight a catalytic role of atoms inside of the nearest-neighbor heterogeneity shell in providing a mechanism for diffusion and proving the existence of an additional thermodynamic boundary in the supercritical carbon dioxide on an intermediate length scale. Finally, we discuss important implications for answering the intriguing question whether Venus may have had CO2 oceans and urge for an experimental detection of this persistent local-order heterogeneity.

HMGB1 is involved in chronic rejection of cardiac allograft via promoting inflammatory-like mDCs

Chronic rejection that leads to diffuse narrowing and occlusion of graft vessels is the most important cause of morbidity and mortality following cardiac transplantation. The role and underlying mechanism of high-mobility group box 1 (HMGB1), as an established inflammatory mediator in acute rejection, remains poorly understood in chronic rejection. Here, we assessed the effects and mechanisms of HMGB1 on the chronic rejection using single MHC Class II-mismatched mouse cardiac transplantation model. It was found that HMGB1 was increased accompanying with the development of chronic rejection, while blockade of HMGB1 with specific neutralizing mAb substantially ameliorated chronic rejection-mediated vasculopathy and fibrosis of allograft, as well as markedly decreased T cell infiltration and production of IL-17A and interferon-gamma in allograft and recipient's spleen. Further, anti-HMGB1 antibody treatment significantly declined the number and frequency of mature dendritic cells (DCs) in allograft and recipient's spleen, especially CD11b(+) Ly6C(high) matured DCs that share the phenotypes with inflammatory-DCs. These findings indicate that HMGB1 contributes to chronic rejection, and HMGB1 blockade may be a novel mean to disrupt the proinflammatory loop after heart transplantation.

Development of eight novel microsatellite markers for Huoyan geese

In this study, we isolated microsatellite DNA from the Huoyan goose genome with magnetic beads. As a result, 150 positive clones were identified, and 148 microsatellites were found. Among the 148 microsatellites, 69.6% were perfect, 17.6% were imperfect, and the rest were compound type (12.8%). Twenty microsatellite primers were used to screen 90 individuals from 3 Huoyan goose populations. Eight loci were polymorphic with a low number of alleles (2 to 4). The observed and expected heterozygosities ranged from 0.3556 to 1 and from 0.2923 to 0.6868, respectively. All the 8 polymorphic loci were in Hardy-Weinberg equilibrium. These molecular markers will be useful for future studies on population genetic structure and conservation genetics in Huoyan geese.

Overexpression of superoxide dismutase 3 gene blocks high-fat diet-induced obesity, fatty liver and insulin resistance

Oxidative stress plays an important role in the development of obesity and obesity-associated metabolic disorders. As an endogenous antioxidant enzyme, superoxide dismutase 3 (SOD3) has the potential to affect diet-induced obesity and obesity associated complications. In the current work, we overexpressed SOD3 in C57BL/6 mice fed a high fat diet to study its effect on high fat diet-induced obesity, fatty liver and insulin resistance. We demonstrated that the Sod3 gene transfer blocked high fat diet induced obesity, fatty liver and insulin resistance. Real Time PCR analysis of adipose and liver tissues revealed that overexpression of the Sod3 gene suppressed expression of pro-inflammatory genes in adipose tissue including F4/80, Tnfα, Cd11c, Mcp1 and Il6, and increased expression of anti-inflammatory genes such as adiponectin. In the liver, high levels of SOD3 activity in animals enhanced expression of the genes responsible for energy expenditure including Cpt1α, Cpt1β, Pgc1α, Pgc1β and Ucp2. These results suggest that overexpression of the Sod3 gene through gene transfer is an effective approach in preventing diet induced obesity and obesity-associated complications.

Nematic twist-bend phase with nanoscale modulation of molecular orientation

A state of matter in which molecules show a long-range orientational order and no positional order is called a nematic liquid crystal. The best known and most widely used (for example, in modern displays) is the uniaxial nematic, with the rod-like molecules aligned along a single axis, called the director. When the molecules are chiral, the director twists in space, drawing a right-angle helicoid and remaining perpendicular to the helix axis; the structure is called a chiral nematic. Here using transmission electron and optical microscopy, we experimentally demonstrate a new nematic order, formed by achiral molecules, in which the director follows an oblique helicoid, maintaining a constant oblique angle with the helix axis and experiencing twist and bend. The oblique helicoids have a nanoscale pitch. The new twist-bend nematic represents a structural link between the uniaxial nematic (no tilt) and a chiral nematic (helicoids with right-angle tilt).

Theories predict the existence of a nematic liquid crystal phase with a local twist-bend structure, but no experimental proof is available over the past 40 years. Borshch et al. identify this phase for the first time in two different materials containing dimeric molecules.

Linezolid in the treatment of extensively drug-resistant tuberculosis

PURPOSE

To investigate the linezolid (LZD) treatment outcome and correlation between in vitro susceptibility to LZD and clinical outcome.

METHODS

We retrospectively reviewed records of tuberculosis (TB) patients who received treatment with linezolid between March 2012 and February 2013.

RESULTS

A total of 43 extensively drug-resistant (XDR) TB patients identified by drug susceptibility testing were enrolled in this study, including 15 (34.9 %) received LZD as part of individualized treatment regimens. Among the 43 XDR TB patients, 15 patients (34.9 %) obtained favorable clinical outcome, including 9 (60.0 %) from LZD group and 6 (21.4 %) from control group without LZD. Statistical analysis revealed that the percentage of favorable outcomes of LZD group was significantly higher than that of control group (P = 0.011). Furthermore, we analyzed the LZD minimum inhibitory concentrations of Mycobacterium tuberculosis (MTB) isolates from patients in LZD group and identified 4 (26.7 %) resistant to LZD. All of the patients with LZD resistance harbored adverse clinical outcome, while most of the patients infected with LZD sensitive MTB harbored favorable clinical outcome (81.8 %, 9/11). Statistical analysis revealed that the percentage of favorable outcome among the patients with LZD resistance was statistically lower than that among the LZD susceptible group (P = 0.011).

CONCLUSION

This study demonstrates that linezolid has efficacy against XDR pulmonary TB patients, even in shorter duration of administration. The XDR TB patients infected with LZD-resistant isolates were more likely to obtain the adverse clinical outcome under the treatment of regimen containing LZD.

Inhibition of eIF2α dephosphorylation enhances TRAIL-induced apoptosis in hepatoma cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an inducer of cancer cell death that holds promise in cancer therapy. Cancer cells are more susceptible than normal cells to the cell-death-inducing effects of TRAIL. However, a variety of cancer cells are resistant to TRAIL through complex mechanisms. Here, we investigate the effects of inhibition of eukaryotic initiation factor 2 subunit α (eIF2α) dephosphorylation on TRAIL-induced apoptosis in hepatoma cells. Treatment of hepatoma cells with salubrinal, an inhibitor of eIF2α dephosphorylation, enhances TRAIL-induced eIF2α phosphorylation, CCAAT/enhancer-binding protein homologous protein (CHOP) expression and caspase activation. Salubrinal enhances TRAIL-induced apoptosis, which could be abrogated by caspase inhibitor. Overexpression of phosphomimetic eIF2α (S51D) enhances TRAIL-induced CHOP expression, caspase 7 and PARP cleavage and apoptosis. By contrast, overexpression of phosphodeficient eIF2α (S51A) abrogates the stimulation of TRAIL-induced apoptosis by salubrinal. Moreover, knockdown of growth arrest and DNA damage-inducible protein 34 (GADD34), which recruits protein phosphatase 1 to dephosphorylate eIF2α, enhances TRAIL-induced eIF2α phosphorylation, CHOP expression, caspase activation and apoptosis. Furthermore, the sensitization of hepatoma cells to TRAIL by salubrinal is dependent on CHOP. Knockdown of CHOP abrogates the stimulation of TRAIL-induced caspase activation and apoptosis by salubrinal. Combination of salubrinal and TRAIL leads to increased expression of Bim, a CHOP-regulated proapoptotic protein. Bim knockdown blunts the stimulatory effect of salubrinal on TRAIL-induced apoptosis. Collectively, these findings suggest that inhibition of eIF2α dephosphorylation may lead to synthetic lethality in TRAIL-treated hepatoma cells.

Controllable morphology and tunable colors of Mg and Eu ion co-doped ZnO by thermal annealing

Controllable morphology and tunable colors of Mg and Eu ion co-doped ZnO by thermal annealing.

Hybrid organic PVDF-inorganic M-rGO-TiO2 (M = Ag, Pt) nanocomposites for multifunctional volatile organic compound sensing and photocatalytic degradation-H2 production

This work focused on the development of a hybrid organic-inorganic TiO2 nanocomposite, which demonstrates the first ever report on harmful volatile organic compound (VOC) sensing and photocatalytic degradation-H2 production. The sensing and photocatalytic properties are enhanced by the synergetic effects of well-structured TiO2 nanotubes, metal nanoparticles and reduced graphene oxide loading for enhanced light absorption and charge-transfer kinetics. Hybridization of a functionalized TiO2 nanocomposite with a polyvinylidene fluoride (PVDF) matrix induced strong cross-linking networks between the inorganic-organic components, which promote mechanical reinforcement-flexibility and highly porous asymmetric structures. The developed solution processable nanocomposite has immense potential to remedy the global environmental and energy issues by producing clean water/air and energy from organic compound waste.

Fibrous hyperplasia involving the orifice of Stensen's duct

This study aimed to describe the clinical features and surgical management of fibrous hyperplasia involving the orifice of Stensen's duct. The clinical data of three patients (one male and two females) were collected and analyzed to characterize this lesion. The lesions surrounding the orifice of Stensen's duct were painless and without obvious causes. The patients' clinical features included sensation of a foreign body and an awkward bite during mastication. All patients received surgical management to resect the polyp and reconstruct the orifice of Stensen's duct. The ducts were preserved intact and parotid glands functioned normally after 12-18 months follow-up. In conclusion, the key point for surgical management of fibrous hyperplasia involving Stensen's duct is to keep the duct intact and unobstructed in consideration of its particular location.

Inhibition of glycogen synthase kinase 3β activity with lithium prevents and attenuates paclitaxel-induced neuropathic pain

Paclitaxel (taxol) is a first-line chemotherapy-drug used to treat many types of cancers. Neuropathic pain and sensory dysfunction are the major toxicities, which are dose-limiting and significantly reduce the quality of life in patients. Two known critical spinal mechanisms underlying taxol-induced neuropathic pain are an increased production of pro-inflammatory cytokines including interleukin-1β (IL-1β) and suppressed glial glutamate transporter activities. In this study, we uncovered that increased activation of glycogen synthase kinase 3beta (GSK3β) in the spinal dorsal horn was concurrently associated with increased protein expressions of GFAP, IL-1β and a decreased protein expression of glial glutamate transporter 1 (GLT-1), as well as the development and maintenance of taxol-induced neuropathic pain. The enhanced GSK3β activities were supported by the concurrently decreased AKT and mTOR activities. The changes of all these biomarkers were basically prevented when animals received pre-emptive lithium (a GSK3β inhibitor) treatment, which also prevented the development of taxol-induced neuropathic pain. Further, chronic lithium treatment, which began on day 11 after the first taxol injection, reversed the existing mechanical and thermal allodynia induced by taxol. The taxol-induced increased GSK3β activities and decreased AKT and mTOR activities in the spinal dorsal horn were also reversed by lithium. Meanwhile, protein expressions of GLT-1, GFAP and IL-1β in the spinal dorsal horn were improved. Hence, suppression of spinal GSK3β activities is a key mechanism used by lithium to reduce taxol-induced neuropathic pain, and targeting spinal GSK3β is an effective approach to ameliorate GLT-1 expression and suppress the activation of astrocytes and IL-1β over-production in the spinal dorsal horn.

Expression of a GDP-L-galactose phosphorylase-like gene in a Chinese wild Vitis species induces responses to Erysiphe necator and defense signaling molecules

Using rapid amplification of cDNA ends, a full-length cDNA sequence of a GDP-L-galactose phosphorylase-like gene was isolated from leaves infected by Erysiphe necator in the Chinese wild (Vitis pseudoreticulata) clone, 'Baihe-35-1', an E. necator-resistant genotype. The full-length cDNA, designated as VpVTC, comprised 1943 bp and putatively encodes a 453-amino acid polypeptide containing an HIT motif. The deduced amino acid sequence showed high similarity with that of VTC genes from other plants. The expression of VpVTC, determined by reverse transcriptase-polymerase chain reaction, was induced by E. necator and defense signaling molecules, including salicylic acid, methyl jasmonate, and ethephon, in 'Baihe-35-1', the V. quinquangularis genotype 'Shang-24', and the E. necator-susceptible V. pseudoreticulata genotype, 'Hunan-1'. Transcript levels of VpVTC correlated well with the degree of disease resistance in the 3 genotypes. Maximum induction of VpVTC by E. necator (>7-fold at 96 h post-inoculation) occurred in 'Baihe-35-1', which also showed the fastest response to signaling molecules. Upregulating the expression of VpVTC in 'Baihe-35-1' resulted in a gradual increase in the ascorbic acid concentration of leaves inoculated with E. necator. Furthermore, VpVTC was expressed in leaves, stems, inflorescence, tendrils, and fruit at all developmental stages, with the highest level occurring in fruit 35 days after flowering.

Overexpression of stearoyl-CoA desaturase 1 in bone-marrow mesenchymal stem cells increases osteogenesis

AIM

The goal of this study was to examine the relationship between stearoyl-CoA desaturase 1 (SCD1) and osteogenesis in bone marrow mesenchymal stem cells (BM-MSCs).

METHODS

SCD1 was overexpressed in BM-MSCs using lentiviral transduction. Then, osteogenesis was induced by low glucose DMEM (10% fetal bovine serum). Alkaline phosphatase (ALP) activity assays, Western blot analyses of SCD1 and osteocalcin, and stainings for ALP and alizarin red were done to assess the extent of osteogenesis in BM-MSCs.

RESULTS

ALP activity was markedly higher in the SCD1 overexpressing cells compared with cells transduced with empty vector or control (untransduced) cells at 1 and 2 weeks after osteogenic induction. By contrast, ALP activities were comparable between control cells and cells transduced with empty vector. Western blot analysis demonstrated that osteocalcin levels were higher in the SCD1 overexpressing cells, compared with cells transduced with empty vector or control cells, at 1 and 2 weeks after osteogenic induction. These findings were corroborated by stainings for ALP and alizarin red that demonstrated a more active osteogenesis in the SCD1 overexpressing cells 2 weeks after osteogenic induction.

CONCLUSION

Increased levels of SCD1 enhance osteogenesis in BM-MSCs.

Angular distribution of diffuse reflectance from incoherent multiple scattering in turbid media

The angular distribution of diffuse reflection is elucidated with greater understanding by studying a homogeneous turbid medium. We modeled the medium as an infinite slab and studied the reflection dependence on the following three parameters: the incident direction, optical depth, and asymmetry factor. The diffuse reflection is produced by incoherent multiple scattering and is solved through radiative transfer theory. At large optical depths, the angular distribution of the diffuse reflection with small incident angles is similar to that of a Lambertian surface, but, with incident angles larger than 60°, the angular distributions have a prominent reflection peak around the specular reflection angle. These reflection peaks are found originating from the scattering within one transport mean free path in the top layer of the medium. The maximum reflection angles for different incident angles are analyzed and can characterize the structure of angular distributions for different asymmetry factors and optical depths. The properties of the angular distribution can be applied to more complex systems for a better understanding of diffuse reflection.

Coordinate phosphorylation of multiple residues on single AKT1 and AKT2 molecules

Aberrant AKT activation is prevalent across multiple human cancer lineages providing an important new target for therapy. Twenty-two independent phosphorylation sites have been identified on specific AKT isoforms likely contributing to differential isoform regulation. However, the mechanisms regulating phosphorylation of individual AKT isoform molecules have not been elucidated because of the lack of robust approaches able to assess phosphorylation of multiple sites on a single AKT molecule. Using a nanofluidic proteomic immunoassay (NIA), consisting of isoelectric focusing followed by sensitive chemiluminescence detection, we demonstrate that under basal and ligand-induced conditions that the pattern of phosphorylation events is markedly different between AKT1 and AKT2. Indeed, there are at least 12 AKT1 peaks and at least 5 AKT2 peaks consistent with complex combinations of phosphorylation of different sites on individual AKT molecules. Following insulin stimulation, AKT1 was phosphorylated at Thr308 in the T-loop and Ser473 in the hydrophobic domain. In contrast, AKT2 was only phosphorylated at the equivalent sites (Thr309 and Ser474) at low levels. Further, Thr308 and Ser473 phosphorylation occurred predominantly on the same AKT1 molecules, whereas Thr309 and Ser474 were phosphorylated primarily on different AKT2 molecules. Although basal AKT2 phosphorylation was sensitive to inhibition of phosphatidylinositol 3-kinase (PI3K), basal AKT1 phosphorylation was essentially resistant. PI3K inhibition decreased pThr451 on AKT2 but not pThr450 on AKT1. Thus, NIA technology provides an ability to characterize coordinate phosphorylation of individual AKT molecules providing important information about AKT isoform-specific phosphorylation, which is required for optimal development and implementation of drugs targeting aberrant AKT activation.

Accuracy improvement of quantitative analysis by spatial confinement in laser-induced breakdown spectroscopy

To improve the accuracy of quantitative analysis in laser-induced breakdown spectroscopy, the plasma produced by a Nd:YAG laser from steel targets was confined by a cavity. A number of elements with low concentrations, such as vanadium (V), chromium (Cr), and manganese (Mn), in the steel samples were investigated. After the optimization of the cavity dimension and laser fluence, significant enhancement factors of 4.2, 3.1, and 2.87 in the emission intensity of V, Cr, and Mn lines, respectively, were achieved at a laser fluence of 42.9 J/cm(2) using a hemispherical cavity (diameter: 5 mm). More importantly, the correlation coefficient of the V I 440.85/Fe I 438.35 nm was increased from 0.946 (without the cavity) to 0.981 (with the cavity); and similar results for Cr I 425.43/Fe I 425.08 nm and Mn I 476.64/Fe I 492.05 nm were also obtained. Therefore, it was demonstrated that the accuracy of quantitative analysis with low concentration elements in steel samples was improved, because the plasma became uniform with spatial confinement. The results of this study provide a new pathway for improving the accuracy of quantitative analysis of LIBS.

LXRα-mediated downregulation of FOXM1 suppresses the proliferation of hepatocellular carcinoma cells

Liver X receptors (LXRs), including LXRα and LXRβ isoforms, have important roles in the metabolic regulation of glucose, cholesterol and lipid. Moreover, activation of LXRs also represses the expression of cyclin D1 and cyclin B1, and thus suppresses the proliferation of multiple cancer cells, but the relevant mechanism is not well known. Forkhead box M1 (FOXM1) is a proliferation-specific member of forkhead box family, which is highly expressed in proliferating normal cells and numerous cancer cells. FOXM1 directly activates transcription of cyclin D1 and cyclin B1, resulting in the enhancement of cell cycle progression and cell proliferation. However, it is unclear whether LXRs are involved in the regulation of FOXM1. In this study, we demonstrated that specific LXRs agonists downregulated expression of FOXM1, cyclin D1 and cyclin B1 in hepatocellular carcinoma (HCC) cells, which led to cell cycle and cell proliferation arrest. Knockdown of FOXM1 significantly alleviated LXRs activation-mediated cell cycle arrest and cell growth suppression. Reporter assays showed that the activation of LXRs significantly reduced the transcriptional activity of FOXM1 promoter. Electrophoretic mobility shift assay and chromatin immunoprecipitation assays demonstrated that LXRα but not LXRβ could bind to an inverted repeat IR2 (-52CCGTCAcgTGACCT-39) in the promoter region of FOXM1 gene. Moreover, the xenograft tumor growth and the corresponding FOXM1 expression in nude mice were dramatically repressed by LXRs agonists. Taken together, we conclude that LXRα but not LXRβ functions as a transcriptional repressor for FOXM1 expression. The pathway 'LXRα-FOXM1-cyclin D1/cyclin B1' is a novel mechanism by which LXRs suppress the proliferation of HCC cells, suggesting that the pathway may be a novel target for HCC treatment.

Clinicopathological study of distant metastases of salivary adenoid cystic carcinoma

Most studies of the clinicopathological characteristics and prognosis of patients with distant metastasis of salivary adenoid cystic carcinoma (SACC) have used small patient samples. To further explore this issue, a descriptive and prognostic study of 467 patients with SACC who were treated from 1963 to 2009 was conducted at a single institution. One hundred and forty-five patients (31.0%) had distant metastases. At least 20% of patients who presented with the early-stage disease and no recurrence developed distant metastasis. The overall 5-, 10-, and 20-year survival rates were 85.6%, 67.4%, and 50.4%, respectively, for patients without distant metastasis, and 69.1%, 45.7%, and 14.3%, respectively, for patients with distant metastasis. The median survival time after distant metastasis was 36 months (range 1-112 months). The prognosis was similar between patients who received treatment for metastasis and those who did not. Patients who were diagnosed with early-stage disease and without local recurrence of the primary tumours could also develop distant metastases. The biological characteristics of adenoid cystic carcinoma were different from those of squamous cell carcinoma. At present, the effectiveness of treatment for distant metastases is not ideal and further research is needed.

Genetic analysis of differentiation of T-helper lymphocytes

In the human immune system, T-helper cells are able to differentiate into two lymphocyte subsets: Th1 and Th2. The intracellular signaling pathways of differentiation form a dynamic regulation network by secreting distinctive types of cytokines, while differentiation is regulated by two major gene loci: T-bet and GATA-3. We developed a system dynamics model to simulate the differentiation and re-differentiation process of T-helper cells, based on gene expression levels of T-bet and GATA-3 during differentiation of these cells. We arrived at three ultimate states of the model and came to the conclusion that cell differentiation potential exists as long as the system dynamics is at an unstable equilibrium point; the T-helper cells will no longer have the potential of differentiation when the model reaches a stable equilibrium point. In addition, the time lag caused by expression of transcription factors can lead to oscillations in the secretion of cytokines during differentiation.

Abstract P6-05-15: Glucocorticoids has diverse effect on the tumorigenicity in estrogen receptor positive and estrogen recptor negative cancer cells

Background: Glucocorticoids (GCs) exerts its biologic effects via GC receptor (GR), which has been linked to signal transduction pathways inducing apoptosis in many hematological malignancies. Generally, GCs are considered not affecting the growth of gross tumor of most non-hematological solid tumor. However, a recent study using meta-analysis of primary breast tumor gene expression from 1378 early breast cancer patients with long-term follow-up, showing that high levels of GR expression significantly correlated with shorter relapse-free survival in estrogen receptor (ER) negative patients. On the contrary, in ER+ breast cancer patients, high levels of GR expression in tumors were significantly associated with better outcome relative to low levels of GR expression. (Cancer Res. 2011, 15;71: 6360–70). We hypothesized that GC has differential effect on the tumorigenicity in ER+ and ER− breast cancer cells.

Methods: Twelve ER− breast cancer cell lines and 5 ER+ breast cancer cell lines were tested. MTT assay, clonogenic assay and soft agar assay was performed with cancer cells treated with or without dexamethasone (DEX). Flow cytometry were applied to detect the effect of DEX on the expression of cancer stem cell markers after treatment with DEX. Nude mice tail vein injection assay of cancer metastasis was performed to evaluate the in vivo tumorigenicity. Transfection with ER expression vector to MDA-MB231, a triple negative cancer cell, by lipofectamine was carried to determine the role of ER in this scenario.

Results. DEX significantly enhanced colony forming ability and/or tumorigenicity in 12 ER− breast cancer cell lines. However, DEX did not affect the proliferation rate of these cancer cells according to MTT assay. We further explored whether DEX could affect the population of cancer stem-like cell, and thereby resulted in increase of tumorigenicity. By flow cytometry study, we found treatment of DEX significantly increased the number stem cell marker + (for examples, ALDH+) cells in ER− cancer cell lines, but not in ER+ cell lines. Sorting and collection of these stem cell marker + cells demonstrated that they had much higher colony forming efficiency and tumorigenicity. Further, in nude mice model by tail vein injection with MDA-MB-231-Lu2 (derived from lung metastasis of MDA-MB-231 cells after two in vivo passages in nude mice using intracardiac injection), treatment of DEX significantly increased the lung metastatic foci number and size. In contrast, DEX significantly decreased the colony forming ability and tumorigenicity in 5 ER+ cancer cell lines. Short term exposure (72hr) of DEX resulted in increased p21 expression and cell cycle G1 arrest in MCF7, an ER+ cancer cell. Prolong incubation of MCF7 cells with DEX (more than 10 days) induced cell apoptosis. When MDA-MB231 cells were stably transfected with ER, MDA-MB231/ER cells showed similar phenotype as those of ER+ cancer cell lines, i.e., DEX decreased the clonogenic and tumorigenicity ability. Studies on underlying mechanisms are ongoing, and preliminary result showed that there is cross talk between ER and GR.

Conclusions: GC increased tumorigenicity in ER− breast cancer cells, but decrease tumorigenicity in ER+ cancer cells.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-05-15.

Direct observation of smectic layers in thermotropic liquid crystals

We demonstrate subnanometer resolution cryo-TEM imaging of smectic layers in the smectic and nematic phases of two bent-core liquid crystals. Our results show perfect periodicity over several hundred layers in the smectic phase and also provide the first direct evidence of smectic clusters on length scales of 30-50 nm in a nematic liquid crystal. The results are corroborated with small angle x-ray scattering measurements. The observation of smectic clusters in the nematic phase is of special interest in bent-core liquid crystals, where the smectic clusters are stable over wide temperature ranges, in contrast to the well-known pretransitional "cybotactic" clusters that appear only in the vicinity of a bulk smectic phase. The means to characterize and manipulate this nanoscale molecular order could open up completely new liquid crystal-based technologies.

Effect of disorder with long-range correlation on transport in graphene nanoribbon

Transport in disordered armchair graphene nanoribbons (AGR) with long-range correlation between quantum wire contacts is investigated by a transfer matrix combined with Landauer's formula. The metal-insulator transition is induced by disorder in neutral AGR. Therein, the conductance is one conductance quantum for the metallic phase and exponentially decays otherwise, when the length of AGR approaches infinity and far longer than its width. Similar to the case of long-range disorder, the conductance of neutral AGR first increases and then decreases while the conductance of doped AGR monotonically decreases, as the disorder strength increases. In the presence of strong disorder, the conductivity depends monotonically and non-monotonically on the aspect ratio for heavily doped and slightly doped AGR, respectively. For edge disordered graphene nanoribbon, the conductance increases with the disorder strength of long-range correlated disordered while no delocalization exists, since the edge disorder induces localization.