48 research outputs found

    A CsI hodoscope on CSHINE for Bremsstrahlung {\gamma}-rays in Heavy Ion Reactions

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    Bremsstrahlung γ\gamma production in heavy ion reactions at Fermi energies carries important physical information including the nuclear symmetry energy at supra-saturation densities. In order to detect the high energy Bremsstrahlung γ\gamma rays, a hodoscope consisting of 15 CsI(Tl) crystal read out by photo multiplier tubes has been built, tested and operated in experiment. The resolution, efficiency and linear response of the units to γ\gamma rays have been studied using radioactive source and (p,γ)({\rm p},\gamma) reactions. The inherent energy resolution of 1.6%+2%/Eγ1/21.6\%+2\%/E_{\gamma}^{1/2} is obtained. Reconstruction method has been established through Geant 4 simulations, reproducing the experimental results where comparison can be made. Using the reconstruction method developed, the whole efficiency of the hodoscope is about 2.6×10−42.6\times 10^{-4} against the 4π4\pi emissions at the target position, exhibiting insignificant dependence on the energy of incident γ\gamma rays above 20 MeV. The hodoscope is operated in the experiment of 86^{86}Kr + 124^{124}Sn at 25 MeV/u, and a full γ\gamma energy spectrum up to 80 MeV has been obtained.Comment: 9 pages, 19 figure

    A Novel Splicing Mutation Alters DSPP Transcription and Leads to Dentinogenesis Imperfecta Type II

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    Dentinogenesis imperfecta (DGI) type II is an autosomal dominant disease characterized by a serious disorders in teeth. Mutations of dentin sialophosphoprotein (DSPP) gene were revealed to be the causation of DGI type II (DGI-II). In this study, we identified a novel mutation (NG_011595.1:g.8662T>C, c.135+2T>C) lying in the splice donor site of intron 3 of DSPP gene in a Chinese Han DGI-II pedigree. It was found in all affected subjects but not in unaffected ones or other unrelated healthy controls. The function of the mutant DSPP gene, which was predicted online and subsequently confirmed by in vitro splicing analysis, was the loss of splicing of intron 3, leading to the extended length of DSPP mRNA. For the first time, the functional non-splicing of intron was revealed in a novel DSPP mutation and was considered as the causation of DGI-II. It was also indicated that splicing was of key importance to the function of DSPP and this splice donor site might be a sensitive mutation hot spot. Our findings combined with other reports would facilitate the genetic diagnosis of DGI-II, shed light on its gene therapy and help to finally conquer human diseases

    Probing high-momentum component in nucleon momentum distribution by neutron-proton bremsstrahlung {\gamma}-rays in heavy ion reactions

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    The high momentum tail (HMT) of nucleons, as a signature of the short-range correlations in nuclei, has been investigated by the high-energy bremsstrahlung γ\gamma rays produced in 86^{86}Kr + 124^{124}Sn at 25 MeV/u. The energetic photons are measured by a CsI(Tl) hodoscope mounted on the spectrometer CSHINE. The energy spectrum above 30 MeV can be reproduced by the IBUU model calculations incorporating the photon production channel from npnp process in which the HMTs of nucleons is considered. A non-zero HMT ratio of about 15%15\% is favored by the data. The effect of the capture channel np→dγnp \to d\gamma is demonstrated

    Aspect of Clusters Correlation at Light Nuclei Excited State

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    The correlation of αα\alpha\alpha was probed via measuring the transverse momentum pTp_{T} and width δpT\delta p_{T} of one α\alpha, for the first time, which represents the spatial and dynamical essentialities of the initial coupling state in 8^{8}Be nucleus. The weighted interaction vertex of 3α\alpha reflected by the magnitudes of their relative momentums and relative emission angles proves the isosceles triangle configuration for 3α\alpha at the high excited energy analogous Hoyle states.Comment: 8 pages, 9 figure

    Variation of Tensor Force due to Nuclear Medium Effect

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    The enhancement of JÏ€(T)J^{\pi}(T)=3+^{+}(0) state with isospin T=0T=0 excited by the tensor force in the free 6^{6}Li nucleus has been observed, for the first time, relative to a shrinkable excitation in the 6^{6}Li cluster component inside its host nucleus. Comparatively, the excitation of JÏ€(T)J^{\pi}(T)=0+^{+}(1) state with isospin T=1T=1 for these two 6^{6}Li formations take on an approximately equal excitation strength. The mechanism of such tensor force effect was proposed due to the intensive nuclear medium role on isospin TT=0 state.Comment: 6 pages, 4 figure

    Multi-alpha Boson Gas state in Fusion Evaporation Reaction and Three-body Force

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    The experimental evidence for the α\alpha Boson gas state in the 11^{11}C+12^{12}C→\rightarrow23^{23}Mg∗^{\ast} fusion evaporation reaction is presented. By measuring the α\alpha emission spectrum with multiplicity 2 and 3, we provide insight into the existence of a three-body force among α\alpha particles. The observed spectrum exhibited distinct tails corresponding to α\alpha particles emitted in pairs and triplets consistent well with the model-calculations of AV18-UX and chiral effective field theory of NV2-3-la*, indicating the formation of α\alpha clusters with three-body force in the Boson gas state.Comment: 7 pages, 6 figure

    Revisit to the yield ratio of triton and 3^3He as an indicator of neutron-rich neck emission

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    The neutron rich neck zone created in heavy ion reaction is experimentally probed by the production of the A=3A=3 isobars. The energy spectra and angular distributions of triton and 3^3He are measured with the CSHINE detector in 86^{86}Kr +208^{208}Pb reactions at 25 MeV/u. While the energy spectrum of 3^{3}He is harder than that of triton, known as "3^{3}He-puzzle", the yield ratio R(t/3He)R({\rm t/^3He}) presents a robust rising trend with the polar angle in laboratory. Using the fission fragments to reconstruct the fission plane, the enhancement of out-plane R(t/3He)R({\rm t/^3He}) is confirmed in comparison to the in-plane ratios. Transport model simulations reproduce qualitatively the experimental trends, but the quantitative agreement is not achieved. The results demonstrate that a neutron rich neck zone is formed in the reactions. Further studies are called for to understand the clustering and the isospin dynamics related to neck formation

    31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

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    Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

    Investigation of antioxidant edible coating and modified atmosphere packaging for enhancing storability of hazelnut kernels

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    This study investigated the effects of antioxidant edible coating and modified atmosphere packaging for improving storability of dried hazelnut kernels by delaying lipid oxidation and color degradation. Hazelnut kernels were coated with different coating matrix (methylcellulose and chitosan) that contain different antioxidant substances (DL-α-tocopherol acetate, cinnamon essential oil, rosemary essential oil and hazelnut oil) and subjected to an accelerated storage condition at 35 °C for 270 days. Hazelnut kernels were also packed under modified atmosphere (MAP) with 100 % N2 in mylar bags and stored at 35 °C for 180 days. Lipid oxidation (free fatty acids, K232 and K270, peroxide values) and color (browning index) were measured for investigating quality changes during the storage. The free fatty acids of kernels from two packaging experiments remained stable during storage. K232 value of MAP kernels was significantly lower (2.20) than that of control (2.90) at the end of the storage, showing delayed production of conjugated dienes. The chitosan based edible coating with encapsulated cinnamon essential oil and oleic acid (CH/ECO/OA) resulted in significantly (P < 0.05) lower PV values (0.53 meq/kg oil), and all the coated samples had the positive effect on reducing browning index with 12–25 compared with control. K270 (0.04–0.18) remained relatively low throughout the long-term storage. As a result, modified atmosphere packaging performed better than edible coatings. This study demonstrated the importance of implicating proper postharvest technology for reducing lipid oxidation and quality deteriorations of hazelnut kernels during prolonged storage
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