The one-colour resonant two-photon ionization （R2PI） spectrum of the 1-fluoronaphthalene （1FN） dimer has been studied in the wavelength range of 304 to 322 nm by using a supersonic molecular beam and time-of-fligh...The one-colour resonant two-photon ionization （R2PI） spectrum of the 1-fluoronaphthalene （1FN） dimer has been studied in the wavelength range of 304 to 322 nm by using a supersonic molecular beam and time-of-flight mass spectrometry. Compared with the original band 00^0 （at 313.8 nm） of the S1 ← So transition of the 1FN monomer, a red-shifted band was observed in the 1FN dimer spectrum at about 315 nm with a relatively large linewidth, nearly 2 nm. Based on the consideration of inductive effect and ab initio calculations, this red-shifted band is assigned to the first electronic excited transition of the 1FN dimer. A possible geometric structure of the 1FN dimer is also obtained with calculations that the two 1FN molecules are combined through two hydrogen bonds which are formed between the hydrogen atom of a molecule and the fluorine atom of a neighbouring molecule. A time-dependent calculation was also carried out and the results are consistent with the experimental data.展开更多
BACKGROUND Early quantitative assessment of liver fat content is essential for patients with fatty liver disease.Mounting evidence has shown that magnetic resonance(MR)technique has high accuracy in the quantitative a...BACKGROUND Early quantitative assessment of liver fat content is essential for patients with fatty liver disease.Mounting evidence has shown that magnetic resonance(MR)technique has high accuracy in the quantitative analysis of fatty liver,and is suitable for monitoring the therapeutic effect on fatty liver.However,many packaging methods and postprocessing functions have puzzled radiologists in clinical applications.Therefore,selecting a quantitative MR imaging technique for patients with fatty liver disease remains challenging.AIM To provide information for the proper selection of commonly used quantitative MR techniques to quantify fatty liver.METHODS We completed a systematic literature review of quantitative MR techniques for detecting fatty liver,following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol.Studies were retrieved from PubMed,Embase,and Cochrane Library databases,and their quality was assessed using the Quality Assessment of Diagnostic Studies criteria.The Reference Citation Analysis database(https://www.referencecitationanalysis.com)was used to analyze citation of articles which were included in this review.RESULTS Forty studies were included for spectroscopy,two-point Dixon imaging,and multiple-point Dixon imaging comparing liver biopsy to other imaging methods.The advantages and disadvantages of each of the three techniques and their clinical diagnostic performances were analyzed.CONCLUSION The proton density fat fraction derived from multiple-point Dixon imaging is a noninvasive method for accurate quantitative measurement of hepatic fat content in the diagnosis and monitoring of fatty liver progression.展开更多
本文报道了4.2～300K 温度范围的富含 Si 的 Si_(1-x)Ge_x 合金的晶格振动红外透射光谱.实验首次观察到 Ge 杂质诱发的一个新的共振模吸收.结果还表明,直拉法生长的Si_(1-x)Ge_x 合金存在严重的氧沾污,且氧的振动峰随温度的降低向高频...本文报道了4.2～300K 温度范围的富含 Si 的 Si_(1-x)Ge_x 合金的晶格振动红外透射光谱.实验首次观察到 Ge 杂质诱发的一个新的共振模吸收.结果还表明,直拉法生长的Si_(1-x)Ge_x 合金存在严重的氧沾污,且氧的振动峰随温度的降低向高频方向移动.展开更多
The phase difference Δξ between locked islands(2/1 and 3/1) has been found to influence the heat transport on the thermal quench during disruptions by numerical modeling [Hu Q et al 2019Nucl.Fusion 59,016005].To ver...The phase difference Δξ between locked islands(2/1 and 3/1) has been found to influence the heat transport on the thermal quench during disruptions by numerical modeling [Hu Q et al 2019Nucl.Fusion 59,016005].To verify this experimentally,a set of resonant magnetic perturbation(RMP) coils is required to excite coupled magnetic islands with different Δξ.The spectrum analysis shows that the current RMP coils on J-TEXT can only produce sufficient 2/1 and 3/1RMP fields with a limited phase difference of Δξ∈[-75°,75°].In order to broaden the adjustable range of Δξ,a set of coils on the high field side(HFS) is proposed to generate 2/1 and 3/1 RMP fields with Δξ=180°.As a result,RMPs with adjustable Δξ∈[-180°,180°] and sufficient amplitudes could be achieved by applying the HFS coils and the low field side(LFS)coils.This work provides a feasible solution for flexible adjustment of the phase difference between m and m+1 RMP,which might facilitate the study of major disruptions and their control.展开更多
采用噬菌体展示肽库技术筛选雷公藤内酯醇的靶蛋白,得到了一个肽段,并通过酶联免疫吸附(ELISA)和免疫共沉淀验证了该片段对雷公藤内酯醇的结合特异性。用Basic Local Alignment Search Tool(BLAST)进行序列对比后,找到了77个匹配序列,...采用噬菌体展示肽库技术筛选雷公藤内酯醇的靶蛋白,得到了一个肽段,并通过酶联免疫吸附(ELISA)和免疫共沉淀验证了该片段对雷公藤内酯醇的结合特异性。用Basic Local Alignment Search Tool(BLAST)进行序列对比后,找到了77个匹配序列,其中最为匹配的序列是人类类固醇生成因子-1(hSF-1),因此hSF-1可能是雷公藤内酯醇的一个潜在受体。在大肠杆菌中表达纯化了hSF-1的配体结合域(LBD),荧光光谱实验表明雷公藤内酯醇对hSF-1-LBD有荧光淬灭作用、等温滴定量热(ITC)实验表明雷公藤内酯醇与hSF-1-LBD发生焓驱动的特异性结合,表面等离子体共振(SPR)实验表明雷公藤内酯醇可以与hSF-1-LBD剂量依赖性结合,这些都证实了hSF-1与雷公藤内酯醇存在特异性相互作用。展开更多
基金supported by the Doctoral Special Fund of Qufu Normal University of China
文摘The one-colour resonant two-photon ionization （R2PI） spectrum of the 1-fluoronaphthalene （1FN） dimer has been studied in the wavelength range of 304 to 322 nm by using a supersonic molecular beam and time-of-flight mass spectrometry. Compared with the original band 00^0 （at 313.8 nm） of the S1 ← So transition of the 1FN monomer, a red-shifted band was observed in the 1FN dimer spectrum at about 315 nm with a relatively large linewidth, nearly 2 nm. Based on the consideration of inductive effect and ab initio calculations, this red-shifted band is assigned to the first electronic excited transition of the 1FN dimer. A possible geometric structure of the 1FN dimer is also obtained with calculations that the two 1FN molecules are combined through two hydrogen bonds which are formed between the hydrogen atom of a molecule and the fluorine atom of a neighbouring molecule. A time-dependent calculation was also carried out and the results are consistent with the experimental data.
基金Supported by Beijing Municipal Science and Technology Commission,No.Z171100000417056Key Support Project of Guo Zhong Health Care of China General Technology Group,No.SGGK202201001。
文摘BACKGROUND Early quantitative assessment of liver fat content is essential for patients with fatty liver disease.Mounting evidence has shown that magnetic resonance(MR)technique has high accuracy in the quantitative analysis of fatty liver,and is suitable for monitoring the therapeutic effect on fatty liver.However,many packaging methods and postprocessing functions have puzzled radiologists in clinical applications.Therefore,selecting a quantitative MR imaging technique for patients with fatty liver disease remains challenging.AIM To provide information for the proper selection of commonly used quantitative MR techniques to quantify fatty liver.METHODS We completed a systematic literature review of quantitative MR techniques for detecting fatty liver,following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol.Studies were retrieved from PubMed,Embase,and Cochrane Library databases,and their quality was assessed using the Quality Assessment of Diagnostic Studies criteria.The Reference Citation Analysis database(https://www.referencecitationanalysis.com)was used to analyze citation of articles which were included in this review.RESULTS Forty studies were included for spectroscopy,two-point Dixon imaging,and multiple-point Dixon imaging comparing liver biopsy to other imaging methods.The advantages and disadvantages of each of the three techniques and their clinical diagnostic performances were analyzed.CONCLUSION The proton density fat fraction derived from multiple-point Dixon imaging is a noninvasive method for accurate quantitative measurement of hepatic fat content in the diagnosis and monitoring of fatty liver progression.
基金supported by the National Magnetic Confinement Fusion Energy R & D Program of China (Nos. 2018YFE0309102 and 2019YFE03010004)National Natural Science Foundation of China (Nos.12075096, 11905078,and 51821005)
文摘The phase difference Δξ between locked islands(2/1 and 3/1) has been found to influence the heat transport on the thermal quench during disruptions by numerical modeling [Hu Q et al 2019Nucl.Fusion 59,016005].To verify this experimentally,a set of resonant magnetic perturbation(RMP) coils is required to excite coupled magnetic islands with different Δξ.The spectrum analysis shows that the current RMP coils on J-TEXT can only produce sufficient 2/1 and 3/1RMP fields with a limited phase difference of Δξ∈[-75°,75°].In order to broaden the adjustable range of Δξ,a set of coils on the high field side(HFS) is proposed to generate 2/1 and 3/1 RMP fields with Δξ=180°.As a result,RMPs with adjustable Δξ∈[-180°,180°] and sufficient amplitudes could be achieved by applying the HFS coils and the low field side(LFS)coils.This work provides a feasible solution for flexible adjustment of the phase difference between m and m+1 RMP,which might facilitate the study of major disruptions and their control.
文摘采用噬菌体展示肽库技术筛选雷公藤内酯醇的靶蛋白,得到了一个肽段,并通过酶联免疫吸附(ELISA)和免疫共沉淀验证了该片段对雷公藤内酯醇的结合特异性。用Basic Local Alignment Search Tool(BLAST)进行序列对比后,找到了77个匹配序列,其中最为匹配的序列是人类类固醇生成因子-1(hSF-1),因此hSF-1可能是雷公藤内酯醇的一个潜在受体。在大肠杆菌中表达纯化了hSF-1的配体结合域(LBD),荧光光谱实验表明雷公藤内酯醇对hSF-1-LBD有荧光淬灭作用、等温滴定量热(ITC)实验表明雷公藤内酯醇与hSF-1-LBD发生焓驱动的特异性结合,表面等离子体共振(SPR)实验表明雷公藤内酯醇可以与hSF-1-LBD剂量依赖性结合,这些都证实了hSF-1与雷公藤内酯醇存在特异性相互作用。
