Differential isospin-fractionation in dilute asymmetric nuclear matter

The differential isospin-fractionation (IsoF) during the liquid-gas phase transition in dilute asymmetric nuclear matter is studied as a function of nucleon momentum. Within a self-consistent thermal model it is shown that the neutron/proton ratio of the gas phase becomes {\it smaller} than that of the liquid phase for energetic nucleons, although the gas phase is overall more neutron-rich. Clear indications of the differential IsoF consistent with the thermal model predictions are demonstrated within a transport model for heavy-ion reactions. Future comparisons with experimental data will allow us to extract critical information about the momentum dependence of the isovector strong interaction.Comment: Rapid Communication, Phys. Rev. C (2007) in pres

Zigzag graphene nanoribbons without inversion symmetry

Graphene on a substrate will suffer an inversion-symmetry-breaking (ISB) lattice potential. Taking electron-electron interaction into account, we study in this paper the possibility of half-metallicity and noncollinear (NC) magnetic phase for graphene zigzag nanoribbons without inversion symmetry. At half-filling it is found that half-metallic(HM) state can be achieved at an intermediate value of the ISB potential due to its competition with the electron-electron interaction. Away from half-filling, the phase diagrams of doping versus ISB potential for different ribbon width are given, where the regimes for the HM states and NC magnetic state are clearly indicated and discussed. For ribbons with perfect edges, we predict a topological transition between two HM states with different magnetic structures, which is accompanied by an abrupt transition of electrical conductance along the ribbon from $2e^2/h$ to $e^2/h$.Comment: 7 pages, 7 figure

Association between TGFBR1*6A and osteosarcoma: A Chinese case-control study

<p>Abstract</p> <p>Background</p> <p>TGFBR1*6A is a common hypomorphic variant of transforming growth factor β receptor 1 (TGFBR1). TGFBR1*6A is associated with an increased cancer risk, but the association of this polymorphism with osteosarcoma remains unknown. We have measured the frequency of TGFBR1*6A variants in osteosarcoma cases and controls.</p> <p>Methods</p> <p>Our case-control study is based on 168 osteosarcoma patients and 168 age- and gender-matched controls. Blood samples were obtained and the TGFBR1*6A variant determined by PCR amplification and DNA sequencing. The odds ratio (OR) and 95% confidence interval (95% CI) for the TGFBR1*6A polymorphism were calculated by unconditional logistic regression, adjusted for both age and gender. Three models - dominant, additive and recessive - were used to analyze the contribution of the TGFBR1*6A variant to osteosarcoma susceptibility.</p> <p>Results</p> <p>Heterozygotic and homozygotic TGFBR1*6A variants represented 50.4% and 6.0% of the 168 cases, whereas the controls had 18. 5% and 1.3%, respectively. ORs for homozygosity and heterozygosity of the TGFBR1*6A allele were 4.6 [95% CI, 2.33-7.97] and 2.9 [95% CI, 1.59-5.34] in the additive model. There were significant increases in the TGFBR1*6A variants in osteosarcoma cases compared to control in all 3 models. Further analysis showed that TGFBR1*6A genotypes were not associated with gender, age, or tumor location. However, TGFBR1*6A was significantly associated with less metastasis.</p> <p>Conclusions</p> <p>TGFBR1*6A, a dominant polymorphism of TGFBR1, is associated with increased susceptibility and metastasis spread of osteosarcoma.</p

Phase Control on Surface for the Stabilization of High Energy Cathode Materials of Lithium Ion Batteries.

The development of high energy electrode materials for lithium ion batteries is challenged by their inherent instabilities, which become more aggravated as the energy densities continue to climb, accordingly causing increasing concerns on battery safety and reliability. Here, taking the high voltage cathode of LiNi0.5Mn1.5O4 as an example, we demonstrate a protocol to stabilize this cathode through a systematic phase modulating on its particle surface. We are able to transfer the spinel surface into a 30 nm shell composed of two functional phases including a rock-salt one and a layered one. The former is electrochemically inert for surface stabilization while the latter is designated to provide necessary electrochemical activity. The precise synthesis control enables us to tune the ratio of these two phases, and achieve an optimized balance between improved stability against structural degradation without sacrificing its capacity. This study highlights the critical importance of well-tailored surface phase property for the cathode stabilization of high energy lithium ion batteries

The biological effect of 125I seed continuous low dose rate irradiation in CL187 cells

<p>Abstract</p> <p>Background</p> <p>To investigate the effectiveness and mechanism of ¹²⁵I seed continuous low-dose-rate irradiation on colonic cell line CL187 in vitro.</p> <p>Methods</p> <p>The CL187 cell line was exposed to radiation of ⁶⁰Coγ ray at high dose rate of 2 Gy/min and ¹²⁵I seed at low dose rate of 2.77 cGy/h. Radiation responses to different doses and dose rates were evaluated by colony-forming assay. Under ¹²⁵I seed low dose rate irradiation, a total of 12 culture dishes were randomly divided into 4 groups: Control group, and 2, 5, and 10 Gy irradiation groups. At 48 h after irradiation, apoptosis was detected by Annexin and Propidium iodide (PI) staining. Cell cycle arrests were detected by PI staining. In order to investigate the influence of low dose rate irradiation on the MAPK signal transduction, the expression changes of epidermal growth factor receptor (EGFR) and Raf under continuous low dose rate irradiation (CLDR) and/or EGFR monoclonal antibodies were determined by indirect immunofluorescence.</p> <p>Results</p> <p>The relative biological effect (RBE) for ¹²⁵I seeds compared with ⁶⁰Co γ ray was 1.41. Apoptosis rates of CL187 cancer cells were 13.74% ± 1.63%, 32.58% ± 3.61%, and 46.27% ± 3.82% after 2 Gy, 5 Gy, and 10 Gy irradiation, respectively; however, the control group apoptosis rate was 1.67% ± 0.19%. G₂/M cell cycle arrests of CL187 cancer cells were 42.59% ± 3.21%, 59.84% ± 4.96%, and 34.61% ± 2.79% after 2 Gy, 5 Gy, and 10 Gy irradiation, respectively; however, the control group apoptosis rate was 26.44% ± 2.53%. <it>P </it>< 0.05 vs. control groups by Student's t-test were found in every treated group both in apoptosis and in G₂/M cell cycle arrest. After low dose rate irradiation, EGFR and Raf expression increased, but when EGFR was blocked by a monoclonal antibody, EGFR and Raf expression did not change.</p> <p>Conclusion</p> <p>¹²⁵I seeds resulted in more effective inhibition than ⁶⁰Co γ ray high dose rate irradiation in CL187 cells. Apoptosis following G₂/M cell cycle arrest was the main mechanism of cell-killing effects under low dose rate irradiation. CLDR could influence the proliferation of cells via MAPK signal transduction.</p

Proteome analysis of human colorectal cancer tissue using 2-D DIGE and tandem mass spectrometry for identification of disease-related proteins

Laser capture microdissection and two-dimensional difference gel electrophoresis were used to establish the proteomic profiles for tumor and matched adjacent tissues from 12 patients. Differential protein spots were identified by mass spectrometric analysis. The cDNA of the differential protein was transfected into colorectal cancer cells, and the biological behavior of these cells was observed. The proteomic profile in colorectal cancer tissues was significantly different from that in normal adjacent tissues. There was a 1.5-fold difference and 60 differential protein spots between cancer and adjacent tissues. Ten differential protein spots were analyzed. Among them, two protein spots were down-regulated and eight protein spots were up-regulated in the primary tumor tissues. After identification by mass spectrometry, the two down-regulated proteins were carbonic anhydrase II and protein disulfide isomerase, and these eight up-regulated proteins included APC-stimulated guanine nucleotide exchange factor, phosphoglycerate kinase 1, fumarate hydratase, aldolase A, activator protein 2B, glutathione S-transferase A3, Arginase and zinc finger protein 64 homolog. After been transfected with carbonic anhydrase II, the invasive ability, mobility and drug resistance of colon cancer lovo cells were significantly reduced. The proteomic profile was significantly different between colorectal cancer tissues and normal adjacent tissues. The down-regulation of carbonic anhydrase II and protein disulfide isomerase and up-regulation of APC-stimulated guanine nucleotide exchange facto, aldolase A, glutathione S-transferase A3 and arginase were correlated with the onset of colorectal cancer.Key words: Colorectal cancer, proteomics