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Development characteristics of cloud-to-ground lightning with multiple grounding points

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Science China Earth Sciences 2018年第8期61卷 1127-1135页

作者： Bin FAN Ping YUAN xuejuan wang Yang ZHAO Jianyong CEN Yanling SU Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province College of Physics and Electronic Engineering Northwest Normal University School of Atmospheric Physics Nanjing University of Information Science and Technology College of Physics and Information Engineering Shanxi Normal University

Using the optical images of a cloud-to-ground lightning flash with multiple grounding points obtained by a highspeed video system in the Qinghai Province of China along with synchronous radiated electric field information, the propagation characteristic and the electric field change features of the leaders and the grounding behavior of discharge channels are *** addition, the two-dimensional velocity of the leader was estimated and its correlation with the time interval of the corresponding subsequent return stroke, and that with the peak current of return stroke are investigated. The results show that the average distance between the three obvious grounded points of the first return stroke channel is about 512.7 m, and the average time interval between the pulses of the corresponding electric field fast changes is 3.8 μs. Further, the average time interval between electric field pulses from the stepped leader is smaller than that of normal single grounding lightning. The observed lightning in our study has two main channels, namely the left and right channels. Based on our observations, it is clear that the dart leader comes close to the ground in case of the left channel after the first return stroke, but it fails to form a return ***, the right channel exhibits a relatively rare phenomenon in that the subsequent return stroke R2 occurred about 2.1 ms after the dart leader arrived at the ground, which was unusually long; this phenomenon might be attributed to the strong discharge of the first return stroke and insufficient charge accumulation near the grounded point in a timely manner. The two-dimensional velocities for the stepped leader of the two main channels are about 1.23×105 and 1.16×105 m s-1, respectively. A sub-branch of stepped leader for the left channel fails to reach the ground and develops into an attempt leader eventually; this might be attributed to the fact that the main branch connects considerably many sub-branches, which lea

关键词： Multiple grounding lightning High-speed camera Electric field changes Leader

Structural fl exibility and functional interaction of Mediator Cdk8 module

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Protein & Cell 2013年第12期4卷 911-920页

作者： xuejuan wang Jianye wang Zhenrui Ding Jinhua Ji Qianqian Sun Gang Cai School of Life Sciences University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory for Physical Sciences at the Microscale Center for Integrative ImagingHefei 230026China

Mediator is a highly conserved large protein complex(25 proteins,>1000 kD a)and preeminently responsible for eu-karyotic transcription,which contains a dissociable‘Cdk8 module’.Although increasing evidence demonstrates that Cdk8 module plays both positive and negative roles in transcription regulation,the detailed structure,and subu-nit organization,molecular mechanism how it regulates transcription remain *** we used single-particle electron microscopy to characterize the structure and subunit organization of the Cdk8 module and illuminated the substantial mobility of the Med13 subunit results in the structural fl *** Cdk8 module interaction with core Mediator is concurrent with active transcription in *** interaction with the Cdk8 module induces core Mediator into very extended conformation in vitro,which is presumed to be an active functional state of *** together,our results illuminated the detailed archi-tecture of Cdk8 module,and suggested the Cdk8 module could positively regulate transcription by modulating Me-diator conformation.

关键词： Mediator Cdk8 kinase module transcription regulation

Modulation of fatty acid synthase by ATR checkpoint kinase Rad3

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Journal of Molecular Cell Biology 2019年第12期11卷 1098-1100页

作者： Shuwan Qiu Sheng Liu Zannati Ferdous Zaoti xuejuan wang and Gang Cai First Affiliated Hospital of USTC School of Life SciencesHefei National Laboratory for Physical Sciences at MicroscaleUniversity of Science and Technology of ChinaHefei 230027China CAS Center for Excellence in Molecular Cell Science Chinese Academy of SciencesHefei 230026China.

Fatty acid synthase (FAS) is the key enzyme for de novo fatty acid synthesis and exists widely from bacteria to mammalian cells (Schweizer and Hofmann, 2004). It is involved in membrane organization, metabolism regulation, energy storage, and many other processes (Maier et al., 2010). The ataxia telangiectasia-mutated and Rad3-related kinase (ATR) is a master regulator of DNA damage response (DDR) and is highly conserved. ATR is activated by DNA double-strand breaks and various types of DNA replication stresses (Cortez et al., 2001). Recent researches have reported that FAS seems closely related to genome stability (Wu et al., 2016). It has been proved that palmitic acid, the product of FAS, can inhibit ATR phosphorylation and kinase activity in mouse fibroblast (Zeng et al., 2008). These studies suggest that there is a crosstalk between fatty acid metabolism and DDR pathway, but the mechanism remains unknown.

关键词： ATR DDR metabolism

A 18FDG PET/CT-based volume parameter is a predictor of overall survival in patients with local advanced gastric cancer

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Chinese Journal of Cancer Research 2019年第4期31卷 632-640页

作者： Jinling Song Zhongwu Li Puyun Chen Jiangyuan Yu Feng wang Zhi Yang xuejuan wang Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education/Beijing) Department of Nuclear MedicinePeking University Cancer Hospital&InstituteBeijing 100142China Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education/Beijing) Department of PathologyPeking University Cancer Hospital&InstituteBeijing 100142China

Objective: The present study investigated the prognosis value of preoperative fluorodeoxyglucose(FDG)positron emission tomography/computed tomography(PET/CT) in patients with local advanced gastric cancer(LAGC).Methods: In total, 144 patients [median age 63(range: 48-80) years old] with LAGC underwent 18 F-FDG PET/CT prior to any treatment. The maximum standardized uptake values(SUVmax), mean standardized uptake values(SUVmean), metabolic tumor volume(MTV) and total lesion glycolysis(TLG) of the primary lesion were measured on PET/CT and correlated with clinicopathological features and ***: Significant differences in SUVmean, SUVmax, MTV and TLG were found according to Lauren’s classification, histologic grade and T category(P<0.05). During the 26.5-month follow-up, 51(35.4%) patients died and 70(48.6%) exhibited disease progression. The optimal thresholds of MTV and TLG were 15.1 cm^3 and 47.3 cm^3, respectively. The 3-year progression-free survival(PFS) and overall survival(OS) for patients with high TLG values were 30% and 38% compared to 38% and 47% for low TLG values, respectively(P<0.05). Univariate and multifactor analyses demonstrated that lymph node metastasis and T stage were independent prognostic factors for PFS;T stage, histologic grade and TLG were independent prognostic factors for OS(P<0.05). Molecular markers had no relationship with patient’s ***: Metabolic activity of primary gastric tumors from 18 F-FDG PET/CT is a prognostic factor in patients with LAGC.

关键词： Gastric cancer 18F-FDG PET/CT metabolic parameters prognosis

Preclinical characterization and validation of a dual-labeled trastuzumab-based imaging agent for diagnosing breast cancer

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Chinese Journal of Cancer Research 2015年第1期27卷 74-82页

作者： xuejuan wang Melissa B. Aldrich Milton V. Marshall Eva M. Sevick-Muraca Department of Nuclear Medicine Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education) Peking University Cancer Hospital & Institute Division of Molecular Imaging The Brown Foundation Institute of Molecular Medicine University of Texas Health Science Center at Houston

Objective： The combination of both nuclear and fluorescent reporters provides unique opportunities for noninvasive nuclear imaging with subsequent fluorescence image-guided resection and pathology. Our objective was to synthesize and optimize a dual-labeled trastuzumab-based imaging agent that can be used to validate an optical imaging agent with potential use in identifying tumor metastases in human epidermal growth factor receptor 2 （HER2） positive breast cancer patients. Methods： [111In]-DTPA-trastuzumab-IRDye 800 was synthesized by a three-step procedure. Purity, stability, immunoreactivity, internalization and biodistribution were explored in HER2＋ SKBR-3 cells. Biodistribution of [111In]-DTPA-trastuzumab-IRDye 800 was performed in a SKBR-3 xenograft model. Results： [111In]-DTPA-trastuzumab-IRDye 800 demonstrated high purity by both chemical and fluorometric determinations. Both flow cytometry and the Lindmo assay demonstrated a high binding affinity of [111In]-DTPA-trastuzumab-IRDye 800 to HER2-overexpressing cells. The dual-labeled conjugate was stable in PBS, but not in serum after 24 h at 37 ℃. Larger molecules （〉150 kD） were seen after a 24 h-incubation in human serum. Biodistribution studies revealed tumor-specific accumulation of [111In]-DTPA- trastuzumab-IRDye 800 in SKBR-3 tumors, and tumor uptakes at 24 and 48 h were （12.42±1.72）% and （9.96±1.05） %, respectively, following intravenous administration. The tumor-to-muscle ratio was 9.13±1.68 at 24 h, and increased to 12.79±2.13 at 48 h. Liver and kidney showed marked uptake of the dual-labeled imaging agent. Conclusions： [111In]-DTPA-trastuzumab-IRDye 800 is an effective diagnostic biomarker that can be used to validate dual-labeled, molecularly targeted imaging agents and can allow these agents to be translated into clinical practice for identifying HER2＋ lesions.

关键词： Dual-labeling trastuzumab human epidermal growth factor receptor 2 (HER2) near-infrared opticalimaging (NIR optical imaging) radioimmunoscintigraphy

Au(Ⅰ)-BSA nanocomposites with assembling-induced excitation-dependent multicolor emission for dynamic cell imaging

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Science China Chemistry 2023年第1期66卷 174-184页

作者： xuejuan wang Guofeng Liu Kuo Fu Xuping Li Mengting Yao Qinghua Lu Liangliang Zhu Xiang Ma Shanghai Key Laboratory of Chemical Assessment and Sustainability Advanced Research Institute School of Chemical Science and EngineeringTongjiUniversityShanghai200092China Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering Frontiers Science Center for Materiobiology and Dynamic ChemistrySchool of Chemistry and Molecular EngineeringEast China University of Scienceand TechnologyShanghai 200237China State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan University Shanghai 200438China

Excitation wavelength dependent(Ex-De) luminescent materials have attracted intense attention due to their great potential in multicolor bioimaging,dynamic anti-counterfeiting,and light emitting ***,it remains a formidable challenge to construct an Ex-De luminescent biomaterial with green starting materials,excellent biocompatibility,good water solubility,and multiple color emission for dynamic cell *** this work,nanocomposites based on the facile self-assembly strategy of bovine serum albumin(BSA) and Au(Ⅰ)-complex are rationally designed and synthesized to simultaneously present Ex-De fluorescence(429–516 nm) and decent phosphorescence(~615 nm) in a dilute aqueous *** analyses of spectroscopic and microscopic results reveal that the luminescent mechanism of Au(Ⅰ)-BSA nanocomposites is cluster-induced Ex-De fluorescence and metal-to-ligand charge transition(MLCT) based ***,based on the excellent biocompatibility,water-solubility and color-tunable emission over the entire visible region(360–800 nm),the Au(Ⅰ)-BSA nanocomposites are successfully used for cell imaging with multiple and switchable colors on *** is more,the solid tablets of Au(Ⅰ)-BSA nanoparticles showed pressure-responsive luminescence and decent room temperature *** work provides an assembling-induced emission strategy for the design of water-soluble,non-cytotoxic,and color-tunable luminescent biomaterials based on the composite of protein and Au nanoparticles.

关键词： nanocomposites excitation wavelength-dependent emission room temperature phosphorescence assembling-induced emission dynamic cell imaging

Influence of chelator and near-infrared dye labeling on biocharacteristics of dual-labeled trastuzumab-based imaging agents

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Chinese Journal of Cancer Research 2016年第3期28卷 362-369页

作者： xuejuan wang Melissa B Aldrich Zhi Yang Nina Zhou Qing Xie Chen Liu Eva Sevick-Muraca Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education/Beijing) Department of Nuclear MedicinePeking University Cancer Hospital&InstituteBeijing 100142China Center for Molecular Imaging the Brown Foundation Institute of Molecular MedicineUniversity of Texas Health Science Center at HoustonHouston TX 77030USA

Objective： To investigate the effect of fluorescent dye labeling on the targeting capabilities of 111 In- （DTPA）.-trastuzumab-（IRDye 800）m. Methods： Trastuzumab-based conjugates were synthesized and conjugated with diethylenetriaminepentaacetic acid （DTPA） at molar ratios of I, 2, 3 and 5 and with a fluorescent dye （IRDye 800CW） at molar ratios of 1, 3 and 5. Immunoreactivity and internalization were assessed on SKBR-3 cells, overexpressing human epidermal growth factor receptor 2. The stability in human serum and phosphate-buffered saline （PBS） was evaluated. The biodistribution of dual-labeled conjugates was compared with that of 111In-（DTPA）2-trastuzumab in a SKBR-3 xenograft model to evaluate the effect of dye-to-protein ratio. Results： All trastuzumab-based conjugates exhibited a high level of chemical and optical purity. Flow cytometry results showed that increasing dye-to-protein ratios were associated with decreased immunoreactivity. Stability studies revealed that the conjugate was stable in PBS, while in human serum, increased degradation and protein precipitation were observed with increasing dye-to-protein ratios. At 4 h, the percentages of internalization of dual-labeled conjugates normalized by dye-to-protein ratio （m） were 24.88%±2.10%, 19.99%±0.59%, and 17.47%±1.26% for ＂m＂ equal to 1, 3, and 5, respectively. A biodistribution study revealed a progressive decrease in tumor uptake with an increase in the dye-to-protein ratios. The liver, spleen and kidney showed a marked uptake with increased dye-to-protein ratios, particularly in the latter. Conclusions： With non-specific-site conjugation of the fluorescent dye with a protein based on imaging agent, the increase in dye-to-protein ratios negatively impacted the immunoreactivity and stability, indicating a reduced tumor uptake.

关键词： Influence near infrared dye trastuzumab human epidermal growth factor receptor 2 dual-labeled

Influence of reconstruction techniques on PET/CT image quality and quantitative accuracy:a phantom study

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Radiation Detection Technology and Methods 2024年第2期8卷 1171-1186页

作者： Xuesong Su Jianhua Geng Jianing Liu Fengshuo Liu Yichen Wu Rong Zheng xuejuan wang Department of Nuclear Medicine National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100021China

Purpose To investigate the influence of different reconstruction techniques on the quantitative accuracy and image quality of PET/*** The NEMA NU2-2018 image quality phantom was scanned on a GE Discovery Elite PET/CT scanner and the spatial resolution was measured based on NEMA NU2 *** same raw data were reconstructed using five different algorithms:ordered subset expectation maximization(OSEM),OSEM with point spread function(PSF)modeling,OSEM with time-of-flight(TOF),OSEM with TOF and PSF,and filtered back-projection(FBP).The recovery coefficient(RC),contrast recovery coefficient(CRC),and contrast-to-noise ratio(CNR)were calculated for the six hot spheres,the percent background variability(PBV)and coefficient of variation(COV)were calculated for the background,and the residual error(RE)was calculated for lung insert in different image *** The incorporation of PSF modeling showed the smallest transverse FWHM and FWTM at both 1 and 10 cm radical *** combination of PSF modeling and TOF improved RCmean and CRC for all spheres and resulted in the highest ratings for the detectability of 10 mm spheres in human observer *** modeling played a role in reducing the COV within the background region of interest and increasing the CNR of the spheres,and decreased background noise ratings in human observer ***,TOF significantly reduced the RE in lung *** PSF modeling nor TOF had a significant effect on *** to FBP,the OSEM algorithm showed significant advantages in PBV,COV,CNR and RE and human observer ratings of image quality,but worse results for RC_(max),RC_(mean) and *** The integration of TOF and PSF modeling into the OSEM algorithm achieves improvements in both quantitative accuracy and image quality,providing distinct *** modeling improves the spatial resolution and decreases the visual appearance of background *** OSEM algorithm shows significantly better image qu

关键词： Positron emission tomography(PET) Image quality Quantification accuracy Reconstruction techniques Phantom

Architecture of SWI/SNF chromatin remodeling complex

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Protein & Cell 2018年第12期9卷 1045-1049页

作者： Zhihui Zhang xuejuan wang Jiyu Xin Zhenrui Ding Sheng Liu Qianglin Fang Na Yang Rui-min Xu Gang Cai Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences University of Science and Technology of ChinaHefei 230027China CAS Center for Excellence in Molecular Cell Science Chinese Academy of SciencesHefei 230026China National Laboratory of Biomacromolecules Institute of BiophysicsChinese Academy of SciencesBeijing 100101China

The SWI/SNF complex is a large ATP-dependent chromatin remodeling complex that is highly conserved from yeast to human, which is essential for transcription regulation, genomic stability, DNA repair and many aspects of development (Kasten et al., 2011). SWI/SNF contains more than 10 subunits (M.W. >1 MDa), including a DNA-dependent ATPase subunit and several accessory subunits. Mutations in several SWI/SNF subunits have been recently identified at a high frequency in a variety of cancers (Masliah-Planchon et al., 2015). Despite the fundamental importance, the structural information of the SWI/SNF complex has been limited to only low-resolution electron microscopy (EM) reconstructions (23-30 A) without subunits localization and the lack of SWI/SNF-nucleosome structure (Smith et al., 2003; Dechassa et al., 2008).

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