Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al re...Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion reactors.At the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He reaction.The^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of Sciences.The neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb reaction.The measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature data.The newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental values.The obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc.展开更多
Interest has recently emerged in potential applications of(n,2n)reactions of unstable nuclei.Challenges have arisen because of the scarcity of experimental cross-sectional data.This study aims to predict the(n,2n)reac...Interest has recently emerged in potential applications of(n,2n)reactions of unstable nuclei.Challenges have arisen because of the scarcity of experimental cross-sectional data.This study aims to predict the(n,2n)reaction cross-section of long-lived fission products based on a tensor model.This tensor model is an extension of the collaborative filtering algorithm used for nuclear data.It is based on tensor decomposition and completion to predict(n,2n)reaction cross-sections;the corresponding EXFOR data are applied as training data.The reliability of the proposed tensor model was validated by comparing the calculations with data from EXFOR and different databases.Predictions were made for long-lived fission products such as^(60)Co,^(79)Se,^(93)Zr,^(107)P,^(126)Sn,and^(137)Cs,which provide a predicted energy range to effectively transmute long-lived fission products into shorter-lived or less radioactive isotopes.This method could be a powerful tool for completing(n,2n)reaction cross-sectional data and shows the possibility of selective transmutation of nuclear waste.展开更多
Unreduced gametes through chromosome doubling play a major role in the process of plant polyploidization.Our previous work confirmed that Camellia oleifera can produce natural 2n pollen,and it is possible to induce th...Unreduced gametes through chromosome doubling play a major role in the process of plant polyploidization.Our previous work confirmed that Camellia oleifera can produce natural 2n pollen,and it is possible to induce the 2n pollen formation by high temperature treatment.This study focused on the optimization of the 2n pollen induction technique and the mechanisms of high temperature-induced2n pollen formation in C.oleifera.We found that the optimal protocol for inducing 2n pollen via high temperature was to perform 45℃with4 h at the prophaseⅠstage of the pollen mother cells(PMCs).Meanwhile,high temperature significantly decreased the yield and fertility of2n pollen.Through the observation of meiosis,abnormal chromosome and cytological behaviour was discovered under high-temperature treatment,and we confirmed that the formation of 2n pollen is caused by abnormal cell plate.Based on weighted gene co-expression network analysis,fifteen hub genes related to cell cycle control were identified.After male flower buds were exposed to heat shock,polygalacturonase gene(CoPGX3)was significantly upregulated.We inferred that high temperature causes the CoPGX3 gene to be overexpressed and that CoPGX3 is redistributed into the cytosol where it degrades cytoplasmic pectin,which leads to an abnormal cell plate.Furthermore,abnormal cytokinesis resulted in the formation of dyads and triads,and PMCs divided to produce 2n pollen.Our findings provide new insights into the mechanism of 2n pollen induced by high temperature in a woody plant and lay a foundation for further ploidy breeding of C.oleifera.展开更多
目的初步探讨TC2N基因对皮肤黑色素瘤(skin cutaneous melanoma,SKCM)发生的影响及其作用机制。方法使用人类蛋白质图谱(The Human Protein Atlas,HPA)和肿瘤基因图谱(The Cancer Genome Atlas,TCGA)数据库分析TC2N在SKCM中的表达及与...目的初步探讨TC2N基因对皮肤黑色素瘤(skin cutaneous melanoma,SKCM)发生的影响及其作用机制。方法使用人类蛋白质图谱(The Human Protein Atlas,HPA)和肿瘤基因图谱(The Cancer Genome Atlas,TCGA)数据库分析TC2N在SKCM中的表达及与临床病理特征的关系。利用人黑色素瘤A375构建TC2N基因的过表达细胞模型,采用CCK-8法检测TC2N在细胞增殖中的作用。利用TC2N基因敲除小鼠构建皮肤黑色素移植瘤模型,观察并测量移植瘤的生长,通过免疫组化测定Ki67在移植瘤组织中的表达,分析肿瘤细胞的增殖。此外,进行基因集富集分析(Gene Set Enrichment Analysis,GSEA)探索TC2N表达与ERK/MAPK信号通路的相关性,并利用RT-qPCR和Western blot法检测相关基因CyclinD1、c-Myc、CDK2和CyclinE1在体内外的mRNA及蛋白表达水平。结果与正常皮肤组织比较,SKCM组织中TC2N的表达水平更高,且TC2N基因的高表达与SKCM患者的临床病理分期和淋巴结转移显著相关(P<0.05)。体外细胞实验发现,过表达TC2N基因后,A375细胞的增殖能力显著增加(P<0.05)。敲除小鼠皮下移植瘤模型结果显示,与TC2N^(+/+)小鼠比较,TC2N-/-小鼠肿瘤质量和体积明显降低(P<0.05),提示TC2N基因敲除后显著抑制SKCM的生长。GSEA富集分析提示TC2N与MAPK信号通路显著相关(P<0.01),且TC2N基因与ERK/MAPK下游基因表达呈正相关(P<0.01)。体内外实验均发现,TC2N表达显著促进ERK与p-ERK表达,且影响ERK相关分子CyclinD1、c-Myc、CDK2和CyclinE1的mRNA和蛋白的表达水平(P<0.01)。结论TC2N基因可能通过激活ERK/MAPK信号通路促进皮肤黑色素瘤的生长。展开更多
A lead-shielded HPGe detector and offlineγ-ray spectra of the residual product were used to measure the cross section(CS)and ratios of isomeric CS(σm/σg)in^(134)Xe(n,2n)^(133m),gXe reactions at different energies(1...A lead-shielded HPGe detector and offlineγ-ray spectra of the residual product were used to measure the cross section(CS)and ratios of isomeric CS(σm/σg)in^(134)Xe(n,2n)^(133m),gXe reactions at different energies(13.5 MeV,13.8 MeV,14.1 MeV,14.4 MeV,14.8 MeV)relative to the^(93)Nb(n,2n)^(92)mNb reaction CS.The target was high-purity natural Xe gas under high pressure.The T(d,n)4He reaction produces neutrons.TALYS code(version 1.95)for nuclear reactions was used for calculations,with default parameters and nuclear level density models.The uncertainties in the measured CS data were thoroughly analyzed using the covariance analysis method.The results were compared with theoretical values,evaluation data,and previous experimental findings.CS data of the 134Xe(n,2n)133mXe and 134Xe(n,2n)133gXe reactions and the corresponding isomeric CS ratios at 13.5 MeV,13.8 MeV,and 14.1 MeV neutron energies are reported for the first time.This research advances our knowledge of pre-equilibrium emission in the(n,2n)reaction channel by resolving inconsistencies in the Xe data.展开更多
BACKGROUND At present,there is insufficient medical evidence to determine whether adjuvant chemotherapy is necessary for T2N0M0 gastric cancer.AIM To obtain a risk score to assess the need for adjuvant chemotherapy in...BACKGROUND At present,there is insufficient medical evidence to determine whether adjuvant chemotherapy is necessary for T2N0M0 gastric cancer.AIM To obtain a risk score to assess the need for adjuvant chemotherapy in patients with T2N0M0 gastric cancer.METHODS We identified 325 patients with pathological T2N0M0 stage primary gastric cancer at the National Cancer Center between 2011 and 2018.Univariate and multivariate Cox regression analyses were performed to predict factors affecting prognosis.Vascular invasion,tumor site,and body mass index were assessed,and a scoring system was established.We compared the survival outcomes and benefits of adjuvant chemotherapy between the different subgroups.RESULTS Five-year survival rates of the score 0,1,2,and 3 groups were 92%,95%,80%,and 50%,respectively(P<0.001).In the score 2-3 group,five-year survival rates for patients in the adjuvant chemotherapy group and postoperative observation group were 95%and 61%,respectively(P=0.021).CONCLUSION For patients with T2N0M0 stage gastric cancer and two or more risk factors,adjuvant chemotherapy after D2 gastrectomy may have a survival benefit.展开更多
基金the Open Project of Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology(NLK 2022-04)the Central Government Guidance Funds for Local Scientific and Technological Development,China(No.Guike,ZY22096024)+1 种基金the National Natural Science Foundation of China(12065003)Guangxi Key R&D Project(2023AB07029).
文摘Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion reactors.At the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He reaction.The^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of Sciences.The neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb reaction.The measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature data.The newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental values.The obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc.
基金supported by the Key Laboratory of Nuclear Data foundation(No.JCKY2022201C157)。
文摘Interest has recently emerged in potential applications of(n,2n)reactions of unstable nuclei.Challenges have arisen because of the scarcity of experimental cross-sectional data.This study aims to predict the(n,2n)reaction cross-section of long-lived fission products based on a tensor model.This tensor model is an extension of the collaborative filtering algorithm used for nuclear data.It is based on tensor decomposition and completion to predict(n,2n)reaction cross-sections;the corresponding EXFOR data are applied as training data.The reliability of the proposed tensor model was validated by comparing the calculations with data from EXFOR and different databases.Predictions were made for long-lived fission products such as^(60)Co,^(79)Se,^(93)Zr,^(107)P,^(126)Sn,and^(137)Cs,which provide a predicted energy range to effectively transmute long-lived fission products into shorter-lived or less radioactive isotopes.This method could be a powerful tool for completing(n,2n)reaction cross-sectional data and shows the possibility of selective transmutation of nuclear waste.
基金supported by the National Natural Science Foundation of China(Grant No.32101489)Forestry Science and Technology Innovation Program of Hunan Province(Grant No.XLK202101-2)Science and Technology Innovation Platform and Talent Program of Hunan Province(Grant Nos.2023RC3164,2021NK1007)。
文摘Unreduced gametes through chromosome doubling play a major role in the process of plant polyploidization.Our previous work confirmed that Camellia oleifera can produce natural 2n pollen,and it is possible to induce the 2n pollen formation by high temperature treatment.This study focused on the optimization of the 2n pollen induction technique and the mechanisms of high temperature-induced2n pollen formation in C.oleifera.We found that the optimal protocol for inducing 2n pollen via high temperature was to perform 45℃with4 h at the prophaseⅠstage of the pollen mother cells(PMCs).Meanwhile,high temperature significantly decreased the yield and fertility of2n pollen.Through the observation of meiosis,abnormal chromosome and cytological behaviour was discovered under high-temperature treatment,and we confirmed that the formation of 2n pollen is caused by abnormal cell plate.Based on weighted gene co-expression network analysis,fifteen hub genes related to cell cycle control were identified.After male flower buds were exposed to heat shock,polygalacturonase gene(CoPGX3)was significantly upregulated.We inferred that high temperature causes the CoPGX3 gene to be overexpressed and that CoPGX3 is redistributed into the cytosol where it degrades cytoplasmic pectin,which leads to an abnormal cell plate.Furthermore,abnormal cytokinesis resulted in the formation of dyads and triads,and PMCs divided to produce 2n pollen.Our findings provide new insights into the mechanism of 2n pollen induced by high temperature in a woody plant and lay a foundation for further ploidy breeding of C.oleifera.
文摘目的初步探讨TC2N基因对皮肤黑色素瘤(skin cutaneous melanoma,SKCM)发生的影响及其作用机制。方法使用人类蛋白质图谱(The Human Protein Atlas,HPA)和肿瘤基因图谱(The Cancer Genome Atlas,TCGA)数据库分析TC2N在SKCM中的表达及与临床病理特征的关系。利用人黑色素瘤A375构建TC2N基因的过表达细胞模型,采用CCK-8法检测TC2N在细胞增殖中的作用。利用TC2N基因敲除小鼠构建皮肤黑色素移植瘤模型,观察并测量移植瘤的生长,通过免疫组化测定Ki67在移植瘤组织中的表达,分析肿瘤细胞的增殖。此外,进行基因集富集分析(Gene Set Enrichment Analysis,GSEA)探索TC2N表达与ERK/MAPK信号通路的相关性,并利用RT-qPCR和Western blot法检测相关基因CyclinD1、c-Myc、CDK2和CyclinE1在体内外的mRNA及蛋白表达水平。结果与正常皮肤组织比较,SKCM组织中TC2N的表达水平更高,且TC2N基因的高表达与SKCM患者的临床病理分期和淋巴结转移显著相关(P<0.05)。体外细胞实验发现,过表达TC2N基因后,A375细胞的增殖能力显著增加(P<0.05)。敲除小鼠皮下移植瘤模型结果显示,与TC2N^(+/+)小鼠比较,TC2N-/-小鼠肿瘤质量和体积明显降低(P<0.05),提示TC2N基因敲除后显著抑制SKCM的生长。GSEA富集分析提示TC2N与MAPK信号通路显著相关(P<0.01),且TC2N基因与ERK/MAPK下游基因表达呈正相关(P<0.01)。体内外实验均发现,TC2N表达显著促进ERK与p-ERK表达,且影响ERK相关分子CyclinD1、c-Myc、CDK2和CyclinE1的mRNA和蛋白的表达水平(P<0.01)。结论TC2N基因可能通过激活ERK/MAPK信号通路促进皮肤黑色素瘤的生长。
基金supported by the National Natural science Foundation of China(Nos.11875016,12165006).
文摘A lead-shielded HPGe detector and offlineγ-ray spectra of the residual product were used to measure the cross section(CS)and ratios of isomeric CS(σm/σg)in^(134)Xe(n,2n)^(133m),gXe reactions at different energies(13.5 MeV,13.8 MeV,14.1 MeV,14.4 MeV,14.8 MeV)relative to the^(93)Nb(n,2n)^(92)mNb reaction CS.The target was high-purity natural Xe gas under high pressure.The T(d,n)4He reaction produces neutrons.TALYS code(version 1.95)for nuclear reactions was used for calculations,with default parameters and nuclear level density models.The uncertainties in the measured CS data were thoroughly analyzed using the covariance analysis method.The results were compared with theoretical values,evaluation data,and previous experimental findings.CS data of the 134Xe(n,2n)133mXe and 134Xe(n,2n)133gXe reactions and the corresponding isomeric CS ratios at 13.5 MeV,13.8 MeV,and 14.1 MeV neutron energies are reported for the first time.This research advances our knowledge of pre-equilibrium emission in the(n,2n)reaction channel by resolving inconsistencies in the Xe data.
基金the National Natural Science Foundation of China,No.82072734.
文摘BACKGROUND At present,there is insufficient medical evidence to determine whether adjuvant chemotherapy is necessary for T2N0M0 gastric cancer.AIM To obtain a risk score to assess the need for adjuvant chemotherapy in patients with T2N0M0 gastric cancer.METHODS We identified 325 patients with pathological T2N0M0 stage primary gastric cancer at the National Cancer Center between 2011 and 2018.Univariate and multivariate Cox regression analyses were performed to predict factors affecting prognosis.Vascular invasion,tumor site,and body mass index were assessed,and a scoring system was established.We compared the survival outcomes and benefits of adjuvant chemotherapy between the different subgroups.RESULTS Five-year survival rates of the score 0,1,2,and 3 groups were 92%,95%,80%,and 50%,respectively(P<0.001).In the score 2-3 group,five-year survival rates for patients in the adjuvant chemotherapy group and postoperative observation group were 95%and 61%,respectively(P=0.021).CONCLUSION For patients with T2N0M0 stage gastric cancer and two or more risk factors,adjuvant chemotherapy after D2 gastrectomy may have a survival benefit.
