分类： 核科学技术 >> 粒子加速器 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： The concentration of the natural ultra-trace radionuclides 36Cl and 236U in the uranium depended on the neutron flux. In this article, a method for measuring 36Cl and 236U in the same uranium mineral with accelerator mass spectrometry was developed in China Institute of Atomic Energy, providing a protocol of the potential application of 236U in uranium mining, environmental, and geological research. The two samples were from Guangxi and Shanxi province, China, and their ratios 36Cl/Cl and 236U/238U were measured. More experimental data conduced to understand the natural nuclides in the uranium mineral. We plan to conduct more efforts on the research.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-12
Wang, Yan
Wang, Mingxia
Wang, Jian
Xu, Tao
Yin, Sanwen
Jang, Richard
Xue, Zhidong
Jang, Richard
Xu, Tao
摘要： Neuropeptides play a variety of roles in many physiological processes and serve as potential therapeutic targets for the treatment of some nervous-system disorders. In recent years, there has been a tremendous increase in the number of identified neuropeptides. Therefore, we have developed NeuroPep, a comprehensive resource of neuropeptides, which holds 5949 non-redundant neuropeptide entries originating from 493 organisms belonging to 65 neuropeptide families. In NeuroPep, the number of neuropeptides in invertebrates and vertebrates is 3455 and 2406, respectively. It is currently the most complete neuropeptide database. We extracted entries deposited in UniProt, the database (www.neuropeptides.nl) and NeuroPedia, and used text mining methods to retrieve entries from the MEDLINE abstracts and full text articles. All the entries in NeuroPep have been manually checked. 2069 of the 5949 (35%) neuropeptide sequences were collected from the scientific literature. Moreover, NeuroPep contains detailed annotations for each entry, including source organisms, tissue specificity, families, names, post-translational modifications, 3D structures (if available) and literature references. Information derived from these peptide sequences such as amino acid compositions, iso-electric points, molecular weight and other physicochemical properties of peptides are also provided. A quick search feature allows users to search the database with keywords such as sequence, name, family, etc., and an advanced search page helps users to combine queries with logical operators like AND/OR. In addition, user-friendly web tools like browsing, sequence alignment and mapping are also integrated into the NeuroPep database.
分类： 物理学 >> 核物理学 提交时间： 2024-09-13
摘要： In conventional isochronous mass spectrometry (IMS) performed at a storage ring, the precision of mass measurement for short-lived nuclei depends on the precise determination of the revolution times (Ts) of stored ions. However, the resolution of T inevitably deteriorates due to the magnetic rigidity spread of the ions, resulting in limited mass resolving power. In this work, we measure the betatron tune Q (the number of betatron oscillations within a single revolution) of the ions, and construct a correlation between T and Q. From this correlation, the T are transformed corresponding to a fixed Q with higher resolution. Using the transformed Ts, we re-determine the masses of 63Ge, 65As, 67Se, and 71Kr, which agree well with the mass values measured by the newly developed IMS (Bρ-IMS). We also study the systematics of Coulomb displacement energies (CDEs) and find that the anomalous staggering in CDEs is removed using the new mass values. This method of T transformation is very useful for the conventional IMS equipped with a single time-of-flight detector.
分类： 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间： 2016-05-12
摘要： The integrins, a family of transmembrane proteins, function in cell-to-cell and cell-to-extracellular matrix (ECM) adhesive interactions, and influence cell signaling of cell growth and differentiation. Expression of integrin 6 in three bladder cancer cell lines, HCV29, KK47 and YST1 were quantitatively analyzed by LC-MS using stable isotope labeling by amino acids in cell culture (SILAC), a simple and powerful proteomic strategy. The results showed that the non-invasive bladder cancer cell line KK47 expressed the highest level of integrin alpha 6. The expression of integrin alpha 6 in invasive bladder cancer cell line YTS1 was also higher than in normal bladder epithelial cell line HCV29. Furthermore, these results were confirmed by Western blotting, qPCR, immunohistochemistry and flow cytometry. Clinical data of mRNA 1TGA6 expression pattern from open-access database (www.oncomine.org) showed the same result during bladder cancer progression. All these indicated that integrin alpha 6 is associated with the invasion progress of the bladder cancer. The preliminary data in this study may sparkle the fundamental role of integrin 6 in the research of bladder cancer.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-11
Li, Yan
Shah, Punit
De Marzo, Angelo M.
Chan, Daniel W.
Zhang, Hui
Van Eyk, Jennifer E.
Li, Yan
Lo, Qianqian
Van Eyk, Jennifer E.
摘要： Glycosylation is one of the most common protein modifications. Each glycoprotein can be glycosylated at multiple glycosites, and each glycosites can be modified by different glycans. Due to this heterogeneity of glycosylation, it has proven difficult to study the structure-function relationship of specific glycans and their affected glycoproteins. Here, we report a novel method for rapid and quantitative identification of glycoproteins containing specific glycans. Lectin affinity isolations are followed by chemical immobilization of the captured glycopeptides, allowing the identification of glycoproteins containing specific glycans by subsequent mass spectrometry. The application of the method should be useful to facilitate our understanding of how changes in glycan associate with diseases, and to discover novel glycoproteins with certain glycans that could serve as biomarkers or therapeutic targets.
分类： 核科学技术 >> 辐射物理与技术 提交时间： 2024-10-29
Wang,Qian
Yan,Xinliang
Zhu,Guangyu
Sanjari,Shahab
Mao,Lijun
Zhao,He
Litvinov,YuriA
Chen,Ruijiu
Wang,Meng
Zhang,Yuhu
Yuan,Youjin
Wu,Junxia
Jiao,Hongyang
Yu,Yue
Chen,Zuyi
Luo,Yinfang
摘要： Schottky mass spectrometry utilizing heavy-ion storage rings is a powerful technique for the precise mass and decay half-life measurements of highly charged ions. Owing to the non-destructive ion-detection features of Schottky noise detectors, the number of stored ions in the ring is determined by the peak area in the measured revolution-frequency spectrum. Because of their intrinsic amplitude-frequency characteristic (AFC), Schottky detector systems exhibit varying sensitivities at different frequencies. Using low-energy electron-cooled stored ions, a new method is developed to calibrate the AFC curve of the Schottky detector system of the Cooler Storage Ring (CSRe) storage ring located in Lanzhou, China. Using the amplitude-calibrated frequency spectrum, a notable refinement was observed in the precision of both the peak position and peak area. As a result, the storage lifetimes of the electron-cooled fully-ionized 56Fe26+ ions were determined with high precision at beam energies of 13.7 and 116.4 MeV/u, despite of frequency drifts during the experiment. When electron cooling was turned off, the effective vacuum condition experienced by the 116.4 MeV/u 56Fe26+ ions was determined using amplitude-calibrated spectra, revealing a value of 2×10−10 mbar, which is consistent with vacuum-gauge readings along the CSRe ring. The method reported herein will be adapted for the next-generation storage ring of the HIAF facility under construction in Huizhou, China. It can also be adapted to other storage-ring facilities worldwide to improve precision and enhance lifetime measurements using many ions in the ring.
分类： 物理学 >> 核物理学 提交时间： 2024-08-31
Qian Wang
Xin-Liang Yan
Guang-Yu Zhu
Shahab Sanjari
Li-Jun Mao
He Zhao
Yuri A. Litvinov
Rui-Jiu Chen
Meng Wang
Yu-Hu Zhang
You-Jin Yuan
Jun-Xia Wu
Hong-Yang Jiao
Yue Yu
Zu-Yi Chen
Yin-Fang Luo
摘要： Schottky mass spectrometry utilizing heavy-ion storage rings serves as a powerful technique for precision mass and decay half-life measurements of highly charged ions. The number of stored ions in the ring is determined by the peak area in the revolution frequency spectrum. Due to intrinsic amplitude frequency characteristic (AFC), Schottky detector systems exhibit varying sensitivities at different frequencies. In this paper, a new method was developed in order to calibrate the AFC curve of the Schottky detector system of the CSRe storage ring using low-energy electron-cooled stored ions. With the amplitude-calibrated frequency spectrum, there was a notable refinement in the precision of both the peak position and peak area. As a result, the storage lifetimesof the electron-cooled fully-ionized 56Fe26+ ions were determined with high precision at the beam energy of 13.7 MeV/u and 116.4 MeV/u, despite of frequency drifts during the experiment. When the electron cooling is turned off, the effective vacuum condition experienced by the 116.4 MeV/u 56Fe26+ ions was determined using the amplitude-calibrated spectra, revealing a value of 10−10 mbar which is consistent with the vacuum gauges readings along the CSRe ring. The method reported here can be adapted at other storage ring facilities to improve the precision and enhance the capability of life-time measurement in the ring.
分类： 物理学 >> 交叉学科物理及相关领域的科学与技术 提交时间： 2017-02-07
摘要： ABSTRACT Compound-specific chlorine/bromine isotope analysis (CSIA-Cl/Br) has become a useful approach for degradation pathway investigation and source appointment of halogenated organic pollutants (HOPs). CSIA-Cl/Br is usually conducted by gas chromatography–mass spectrometry (GC–MS) techniques, which could be negatively impacted by chlorine and bromine isotope fractionation of HOPs on GC columns. In this study, 31 organochlorines and 4 organobromines were systematically investigated in terms of chlorine/bromine isotope fractionation on GC columns using GC–double focus magnetic-sector high resolution MS (GC–DFS-HRMS). On-column chlorine/bromine isotope fractionation behaviors of the HOPs were explored, presenting various isotope fractionation modes and extents. Twenty-nine HOPs exhibited inverse isotope fractionation, and only polychlorinated biphenyl-138 (PCB-138) and PCB-153 presented normal isotope fractionation. And no observable isotope fractionation was found for the rest four HOPs, i.e., PCB-101, 1,2,3,7,8-pentachlorodibenzofuran, PCB-180 and 2,3,7,8-tetrachlorodibenzofuran. The isotope fractionation extents of different HOPs varied from below the observable threshold (5.0‰) to 73.1‰ (PCB-18). The mechanisms of the on-column chlorine/bromine isotope fractionation were tentatively interpreted with the Craig-Gordon model and a modified two-film model. Inverse isotope effects and normal isotope effects might contribute to the total isotope effects together and thus determine the isotope fractionation directions and extents. Proposals derived from the main results of this study for CSIA-Cl/Br research were provided for improving the precision and accuracy of CSIA-Cl/Br results. The findings of this study will shed light on the development of CSIA-Cl/Br methods using GC–MS techniques, and help to implement the research using CSIA-Cl/Br to investigate the environmental behaviors and pollution sources of HOPs.
分类： 物理学 >> 核物理学 提交时间： 2025-05-06
Luo, Mr. Yinfang
Lv, Mr. Jiahao
Xing, Dr. Yuan-ming
Zhang, Prof. Yuhu
Zhang, Mr. Min
Wang, Prof. Meng
Litvinov, Prof. Yuri
Zhou, Prof. Xiaohong 周小红
摘要： The technique of Bρ-defined isochronous mass spectrometry (Bρ-IMS), established at a storage ring, serves as a valuable tool for determining the masses of short-lived nuclei. In the previous Bρ-IMS experiments, the effects of magnetic field drifts have to be corrected in order to improve the mass resolving power of Bρ-IMS [Eur. Phys. J. A 59, 27 (2023)]. The correction procedures are complicated and require multiple reference ions with well-known masses in each injection, which may not be the cases in the measurements of exotic nuclei with tiny production yields. In this study, we propose a novel approach of Bρ-IMS that requires only one reference ion for mass determination in an individual injection, avoiding the tedious and complicated correction procedures. This approach achieves the mass precision comparable to that of previous Bρ-IMS results, and is approved to be suitable for future mass measurements of exotic nuclei with extremely low production yields.
分类： 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间： 2016-05-12
Feng, Zhong-Tao
Deng, Yun-Quan
Zhang, Shi-Chao
Liang, Xue
Yuan, Fang
Wang, Bao-Shan
Hao, Jia-Long
Zhang, Jian-Chao
Sun, Shu-Feng
Sun, Shu-Feng
摘要： Recretohalophytes with specialized salt-secreting structures (salt glands) can secrete excess salts from plant, while discriminating between Na+ and K+. K+/Na+ ratio plays an important role in plant salt tolerance, but the distribution and role of K+ in the salt gland cells is poorly understood. In this article, the in situ subcellular localization of K and Na in the salt gland of the recretohalophyte Limonium bicolor Kuntze is described. Samples were prepared by high-pressure freezing (HPF), freeze substitution (FS) and analyzed using NanoSIMS. The salt gland of L. bicolor consists of sixteen cells. Higher signal strength of Na+ was located in the apoplast of salt gland cells. Compared with control, 200 mM NaCl treatment led to higher signal strength of ICE and Na+ in both cytoplasm and nucleus of salt gland cells although K+/Na+ ratio in both cytoplasm and nucleus were slightly reduced by NaCl. Moreover, the rate of Na+ secretion per salt gland of L. bicolor treated with 200 mM NaCl was five times that of controls. These results suggest that K+ accumulation both in the cytoplasm and nucleus of salt gland cells under salinity may play an important role in salt secretion, although the exact mechanism is unknown. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-11
Zhao, Jiating
Gao, Yuxi
Peng, Xiaomin
Li, Yunyun
Xu, Xiaohan
Li, Bai
Dong, Juncai
Li, Yu-Feng
Pu, Yunxia
Wu, Gang
Zhu, Nali
摘要： A comprehensive approach that can identify and quantify selenium (Se) in seleno-proteins in Se-enriched yeast was developed. The Se-containing compounds in Se-enriched yeast were first extracted and then the fraction of Se-containing proteins in the supernatant was analyzed by 2-dimensional electrophoresis (2-DE) and synchrotron radiation X-ray fluorescence (SR-XRF). The detection limit (DL) of SR-XRF analysis for Se quantification in Se-containing proteins after 2-DE separation was calculated to be 0.20 mu g g(-1), which is suitable for Se quantification in the Se-containing spots present on the 2-D gel. After being scanned by SR-XRF, only spots with a mean Se content exceeding twice the DL of SR-XRF were considered to be seleno-proteins. In this way, a total of 157 Se-containing spots in the gel were visually distinguished. Se contents in all the Se-containing proteins of different molecular weights were quantified. The total Se content on the 2-D gel was calculated to be 126.56 mu g g(-1), which covered most of the seleno-proteins on the 2-D gel.
分类： 材料科学 >> 材料科学（综合） 提交时间： 2017-05-09
摘要： Colorimetric sensor arrays demonstrate numerous superior features in chemo- and bio-sensing, but they are generally not applicable to less-reactive analytes. Based on the findings that N-methyl carbamate pesticides could be decomposed into reactive phenols in basic media, herein, a novel strategy of strong base pre-treatment was developed and employed for the colorimetric sensor array detection and differentiation of the N-methyl carbamate pesticides in an indirect manner. With the use of five inexpensive and commercially available phenol responsive indicators, such a colorimetric sensor array can be facilely fabricated. Classification analysis (e.g. hierarchical clustering analysis (HCA) and principal component analysis (PCA)) reveals that the as-fabricated sensor array has an extremely high dimensionality and, consequently, exhibits excellence in discriminating a variety of N-methyl carbamates from other types of pesticides and potential interferants, and further identifying them exactly from each other. Moreover, semi-quantitative detection could also be achieved through combining HCA/PCA, recognition patterns, and corresponding fitting curves. Overall, the as-developed method exhibits high selectivity and sensitivity, good anti-interference, simultaneous detection and identification capability for each of the N-methyl carbamate pesticides, and potential applicability in real samples. Most importantly, this study demonstrates that pre-treatment strategies are very effective in expanding the range of applications of colorimetric sensor array methodology to less-reactive analytes.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-12
Chen, Xiulan
Wei, Shasha
Ji, Yanlong
Guo, Xiaojing
Yang, Fuquan
Chen, Xiulan
Wei, Shasha
Ji, Yanlong
Guo, Xiaojing
Yang, Fuquan
Ji, Yanlong
摘要： SILAC is based on direct addition of selected stable isotope amino acids into the cell culture medium, allowing superior quantitative analysis of the cellular proteome compared to other labeling methods. The great advantages of SILAC lie in its straight-forward implementation, quantitative accuracy, and reproducibility over chemical labeling or label-free quantification strategies, favoring its adoption for proteomic research. SILAC has been widely applied to characterize the proteomic changes between different biological samples, to investigate dynamic changes of protein PTMs, to distinguish specific interacting proteins in interaction proteomic analysis, and to analyze protein turnover in the proteome-wide scale. The present review summarizes the principles of SILAC technology, its applications in biological research, and the present state of this technology.
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