分类: 物理学 提交时间: 2016-05-08
摘要: There are more than eight hundred interest rates published in China bond market every day.Which are the benchmark interest rates that have broad influences on most interest rates is a major concern for economists. In this paper, multi-variable Granger causality test is developed and applied to construct a directed network of interest rates, whose important nodes, regarded as key interest rates, are evaluated with inverse Page Rank scores. The results indicate that some short-term interest rates have larger influences on the most key interest rates, while repo rates are the benchmark of short-term rates. It is also found that central bank bills rates are in the core position of mid-term interest rates network, and treasury bond rates are leading the long-term bonds rates.The evolution of benchmark interest rates is also studied from 2008 to 2014, and it’s found that SHIBOR has generally become the benchmark interest rate in China. In the frequency domain we detect the properties of information flows between interest rates and the result confirms the existence of market segmentation in China bond market.
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: 2016-05-11
摘要: Body size is one of the features that distinguish one species from another in the biological world. Animals have developed mechanisms to control their body size during normal development. However, how animals cope with genetic alterations and/or environmental stresses to develop into normal-sized adults remain poorly understood. The ability of the animals to develop into a normal-sized adult after the challenges of genetic alterations and/or environmental stresses reveals a robustness of body size control. Here we show that the mutation of dGPAT4, a de novo synthase of lysophosphatidic acid, is a genetic alteration that triggers such a robust response of the animals to body size challenges in Drosophila. Loss of dGPAT4 leads to a severe delay of development, slow growth and resultant small-sized animals during the larval stages, but results in normal-sized adult flies. The robust body size adjustment of the dGPAT4 mutant is likely achieved by corresponding changes in ecdysone and insulin signaling, which is also manifested by compromised food intake. Thus, we propose that a strategy has been evolved by the animals to reach final body size when challenged by genetic alterations, which requires the coordinated ecdysone and insulin signaling.
分类: 物理学 >> 核物理学 提交时间: 2016-09-01
摘要: We investigate the charmed baryon production reaction pp¯→ΛcΛ¯c in an effective Lagrangian approach. Besides the t-channel D0 and D∗0 mesons exchanges, the s-channel Y(4630) meson exchange is taken into account. For the total cross sections, the D0 and D∗0 mesons provide minor background contributions, while the Y(4630) state gives a clear peak structure with the magnitude of 10 μb at center of mass energy 4.63 GeV. Basing on the results, we suggest that the reaction of pp¯→ΛcΛ¯c can be used to search for the 1−− charmonium-like Y(4630) state, and our predictions can be tested in future by theP¯ANDA facility.
分类: 核科学技术 >> 裂变堆工程技术 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: To investigate the corrosion products of Cr in molten FLiNaK salt (46.5 mol% LiF11.5 mol% NaF42 mol% KF), the corrosion test of the pure metal Cr was performed in molten FLiNaK salt at 700 ℃ for 200 h. The FLiNaK salt after the corrosion test was thoroughly investigated by X-ray absorption near-edge structure spectroscopy, a transmission electron microscope, and X-ray diffraction. The results demonstrate that the predominant oxidation state of Cr in FLiNaK salt is Cr3+, and the main corrosion product in cooled FLiNaK salt is K2NaCrF6.
分类: 核科学技术 >> 核材料与工艺技术 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: Extensive accumulation of neurofibrillary tangles (NFTs) consistently correlate with the degree of cognitive impairment and neuronal circuitry deterioration associated with Alzheimers disease. However, no PET probe is currently available for selective detection of NFTs in the living human brain. [18F]-THK523 was developed as a potential in vivo imaging probe for tau pathology. In this paper, we report a new protected precursor, 2-((2-(4-(( tert-butoxycarbonyl)amino)phenyl)quinolin-6-yl)oxy)ethyl 4-methylbenzenesulfonate (THK-7), instead of 2-((2-(4-aminophenyl)quinolin-6-yl)oxy)ethyl 4-methylbenzenesulfonate (BF241), and an improved automated radiosynthesis of [18F]-THK523 and the study on chemical kinetics of the labeling reaction of [18F]-THK523, with high-yield (705%, n=6, decay-corrected to end of bombardment), and high radiochemical purity (>90%) and specific activity (2.5 0.5 Ci/mol) from protected precursor on fully automated module at the end of radiosynthesis (4555 min). The chemical kinetics for [18F]-THK523 demonstrates that nucleophilic substitution can be carried out easily with protected precursor.
分类: 核科学技术 >> 核材料与工艺技术 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: Reliable and non-invasive diagnostic tools are highly valuable for successful therapeutic strategies for the treatment of Alzheimers disease (AD). The existence of neurofibrillary tangles (NFTs) consisting of tau protein are one kind of the pathological features of AD, and its level of severity is correlated with the stage of AD. However, no clinically approved positron emission tomography (PET) probe is currently available for selective imaging of neurofibrillary tangles on patients. In this paper, we report our studies on biological characteristics of [18F]-THK523 as a novel tau imaging probe. With low molecular weight, [18F]-THK523 is stable, electrically neutral, lipophilic and non-mass concentration-dependent. Preliminary biological studies have shown the excellent properties of [18F]-THK523 as brain imaging tracer for further research.