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Gao Y, Li MM, Yu HB, Xu GQ, Xu BG, Wu M, Wang N, Liang YC, Wang YL, Han Y. [The success rate of His-Purkinje system pacing in patients with various sites of atrioventricular block]. Zhonghua Xin Xue Guan Bing Za Zhi 2022; 50:543-548. [PMID: 35705462 DOI: 10.3760/cma.j.cn112148-20220403-00238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Objective: To evaluate the success rate of His-Purkinje system pacing (HPSP) in patients with various sites of atrioventricular block (AVB) and provide clinical evidence for the selection of HPSP in patients with AVB. Methods: This is a retrospective case analysis. 637 patients with AVB who underwent permanent cardiac pacemaker implantation and requiring high proportion of ventricular pacing from March 2016 to September 2021 in the Department of Cardiology, General Hospital of Northern Theater Command were enrolled. The site of AVB was determined by electrophysiological examination. His bundle pacing (HBP) was performed in the first 130 patients (20.4%) who were classified as the HBP group and HPSP included HBP and/or left bundle branch pacing (LBBP) was performed in later 507 patients (79.6%) and these patients were classified as the HPSP group. The basic clinical information such as age and sex of the two groups was compared, and the success rates of HBP or HPSP in patients with different sites of AVB and QRS intervals were analyzed. Results: The age of HBP group was (66.4±15.9) years with 75 males (57.7%). The age of HPSP group was (66.8±13.6) years with 288 (56.8%) males. Among 637 patients, 63.0% (401/637) had atrioventricular node block; 22.9% (146/637) had intra-His block; 14.1% (90/637) had distal or inferior His bundle block. Totally, the success rate of HPSP was higher than that of HBP [93.9% (476/507) vs. 86.9% (113/130), P<0.05]. In each group of patients with various AVB sites, the success rate of HPSP was higher than that of HBP respectively and both success rates of HBP and HPSP showed a declining trend with the distant AVB site. The success rate of HBP in patients with atrioventricular node block and intra-His block was higher than that in patients with distal or inferior His bundle block [95.2% (79/83) vs. 47.1% (8/17), P<0.001; 86.7% (26/30) vs. 47.1% (8/17), P=0.010]. The success rate of HPSP was higher than that of HBP in patients with distal or inferior His bundle block [87.7% (64/73) vs 47.1% (8/17), P=0.001]. In patients with QRS<120 ms, 94.9% (520/548) of AVB sites were in atrioventricular node or intra-His, and HBP had a similar high success rate with HPSP [95.6% (109/114) vs. 96.3% (418/434), P=0.943] in these patients. In patients with QRS ≥ 120 ms, 69.7% (62/89) of AVB sites were at distal or inferior His bundle, and the success rate of HBP was only 25.0% (4/16), while the success rate of HPSP was as high as 79.5% (58/73), P<0.001. Conclusions: In patients with QRS<120 ms and atrioventricular node block or intra-His block, success rates of HBP and HPSP are similarly high and HBP might be considered as the first choice. In patients with QRS ≥ 120 ms and AVB site at distal or inferior His bundle, the success rate of HPSP is higher than that of HBP, suggesting LBBP should be considered as the first-line treatment option.
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Affiliation(s)
- Y Gao
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - M M Li
- The Graduate School, Dalian Medical University, Dalian 116044, China
| | - H B Yu
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - G Q Xu
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - B G Xu
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - M Wu
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - N Wang
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - Y C Liang
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - Y L Wang
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - Yaling Han
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
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Lin JP, Chen SQ, Li M, Xu GQ, Zhang T, Wang SZ. [Correlation analysis of cervical spine dysfunction, pain and muscle strength in office workers]. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 2022; 40:192-195. [PMID: 35439860 DOI: 10.3760/cma.j.cn121094-20210511-00249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Objective: To expore the correlation between neck disability, neck pain and muscle strength in cervical pondylosis of office worker, and to provide scientific basis for the prevention and treatment of cervical spondylosis. Methods: In April 2021 ,234 patients with cervical spondylotic myelopathy treated in the Subsidiary Rehabilitation Hospital of Fujian University of Traditional Chinese Medicine from April 2015 to April 2017 were selected, the correlation between Neck Disability Index (NDI) score, neck pain and muscle strength was analyzed using the Spearman rank correlation method. Mann-Whitney U test was used to compare the difference of maximum muscle strength of isometric contraction. Results: NDI score was negatively correlated with neck flexion, extension, and muscle strength in the left and right flexion directions (r(s)=-0.164, -0.169, -0.222, -0.176, P=0.012, 0.010, 0.001 , 0.007). In mild and moderate functional disorder patients, the muscle strength in flexion, extension and left and right flexion direction was greater, the difference was statistically significant (P <0.01). Conclusion: There is a negative correlation between cervical functional disorder and cervical muscle strength in office workers, suggesting that strengthening cervical muscle strength may be a way to improve cervical spine function.
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Affiliation(s)
- J P Lin
- School of Health, Fujian Medical University, Fuzhou 350122, China Fujian Provincial Collaborative Innovation Center of Geriatric Rehabilitation and Industry Promotion, Fuzhou 350122, China
| | - S Q Chen
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China
| | - M Li
- School of Health, Fujian Medical University, Fuzhou 350122, China Fujian Provincial Collaborative Innovation Center of Geriatric Rehabilitation and Industry Promotion, Fuzhou 350122, China
| | - G Q Xu
- School of Health, Fujian Medical University, Fuzhou 350122, China
| | - T Zhang
- School of Health, Fujian Medical University, Fuzhou 350122, China
| | - S Z Wang
- School of Health, Fujian Medical University, Fuzhou 350122, China Fujian Provincial Collaborative Innovation Center of Geriatric Rehabilitation and Industry Promotion, Fuzhou 350122, China
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Liu Y, Xu GQ, Ding QL, Mao EQ, Sheng HQ, Wang XF. [A case of acquired hemophilia A with multiple superficial blistering skin disorders as the main manifestation]. Zhonghua Xue Ye Xue Za Zhi 2021; 41:870. [PMID: 33190449 PMCID: PMC7656075 DOI: 10.3760/cma.j.issn.0253-2727.2020.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Y Liu
- Department of Laboratory Medicine, Ruijin Hospital of Medical College, Shanghai Jiaotong University, Shanghai 200025, China
| | - G Q Xu
- Department of Laboratory Medicine, Ruijin Hospital of Medical College, Shanghai Jiaotong University, Shanghai 200025, China
| | - Q L Ding
- Department of Laboratory Medicine, Ruijin Hospital of Medical College, Shanghai Jiaotong University, Shanghai 200025, China
| | - E Q Mao
- Department of Emergency, Ruijin Hospital of Medical College, Shanghai Jiaotong University, Shanghai 200025, China
| | - H Q Sheng
- Department of Emergency, Ruijin Hospital of Medical College, Shanghai Jiaotong University, Shanghai 200025, China
| | - X F Wang
- Department of Laboratory Medicine, Ruijin Hospital of Medical College, Shanghai Jiaotong University, Shanghai 200025, China
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Yan XL, Liang YC, Yu HB, Xu BG, Gao Y, Liu R, Xu GQ, Wu M. [Application and efficacy of the adjustment on left ventricular electrical delay and the distance between right and left ventricular pacing polar in optimizing the left ventricular pacing polar]. Zhonghua Xin Xue Guan Bing Za Zhi 2020; 48:669-674. [PMID: 32847323 DOI: 10.3760/cma.j.cn112148-20200227-00132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To investigate the application and efficacy of left ventricular (LV) electrical delay (LVED) and the distance of right ventricular(RV) pacing polar to LV(DRLV) in optimizing LV pacing polar. Methods: Heart failure (HF) patients who implanted cardiac resynchronization therapy (CRT) device with a LV quadripolar lead from January 2014 to January 2018 at General Hospital of Northern Theater Command were enrolled in the study. Measurements of LVED and DRLV of each polar of the lead were performed in patients with HF who underwent CRT with LV quadripolar lead. The principle in turn for polar selecting used for clinical LV pacing was the pacing polar: (1)without phrenic nerve stimulation(PNS); (2)with appropriate capture threshold; (3)not located in apical; (4)with maximal LVED; (5)with maximal DRLV. The LV pacing polar was selected for CRT according to the procedure. The distribution of target veins implanted with LV quadripolar lead were calculated. The percentage of biventricular pacing at 6-month follow-up was recorded. The following indexes were compared before and 6-month after surgery, including QRS duration, LV end-systolic volume(LVESV), LV ejection fraction(LVEF), LV end-diastolic dimension(LVEDD), 6 minute walking distance(6MWD), New York Heart Association(NYHA) class. The efficacy and echocardiographic efficacy of CRT was evaluated. Results: There were twenty-nine HF patients enrolled. The mean age of enrolled patients was(61.7±7.6)years old, nineteen (66%)of them were male. There were seventeen(59%) patients diagnosed as dilated cardiomyopathy and twelve(41%) patients as ischemic cardiomyopathy. All patients were successfully implanted with LV quadripolar lead into target veins, and all four pacing sites were also in target veins. Target veins were located in lateral veins in 15 patients (52%), anterior veins in 2 patients (7%), posterior veins in 11 patients (38%), and lateral branches of great cardiac veins in 1 patient (3%). After 6-month of follow-up, the percentage of biventricular pacing was greater than 95%.There were nineteen(66%) patients optimized LV pacing polar by the largest LVED and four (14%) patients by the DRLV. Of the 29 patients, 5(17%) patients used D1 as the pacing polar, 5(17%) patients used M2 as the pacing polar, 7(24%) patients used M3 as the pacing polar, and 12(41%) patients used P4 as the pacing polar. The pacing polars (D1, M2) of traditional bipolar lead were used in 10(34%) patients, and the LV quadripolar lead specific pacing polars (M3, P4) were used in 19(66%) patients.Compared to a LV quadripolar lead, the LV pacing polar (M3, P4) selected in 19(66%) patients were not achievable with the traditional LV bipolar lead (D1, M2). Preoperative QRS duration, LVESV, LVEF, LVEDD, 6MWD and NYHA class were (171±24)ms, (231±79)ml, (28±5)%, (74±11)mm, (294±103)m, (3.2±1.0)class and the postoperative 6-month were (130±12)ms, (158±73)ml, (36±10)%, (66±12)mm, (371±86)m, (1.9±0.5)class. These indexes were significantly improved after 6 months operation(P<0.001). 97% and 83% patients were responders of CRT as assessed by 6-month efficacy and echocardiographic efficacy. Conclusion: The maximal LVED and DRLV can be used to select LV pacing polar with a high rate of CRT response rate.
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Affiliation(s)
- X L Yan
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - Y C Liang
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - H B Yu
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - B G Xu
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - Y Gao
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - R Liu
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - G Q Xu
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - M Wu
- Department of Cardiology, General Hospital of Northern Theater Command, Shenyang 110016, China
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Gao Y, Liang YC, Yu HB, Yan XL, Xu BG, Liu R, Wang N, Xu GQ, Wang ZL. [Heart rate control in chronic heart failure patients received cardiovascular implantable electronic device therapy: effects of optimized medication]. Zhonghua Xin Xue Guan Bing Za Zhi 2018; 46:173-177. [PMID: 29562420 DOI: 10.3760/cma.j.issn.0253-3758.2018.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To investigate the heart rate control situation of chronic heart failure (CHF) patients who received cardiovascular implantable electronic device (CIED) therapy, and to assess the heart rate control efficacy by optimized medication adjustment. Methods: We performed a perspective study in heart failure with reduced left ventricular ejection fraction (HFrEF) patients who received CIED according to guideline recommendations, patients were enrolled from January 2012 to January 2017. Resting heart rate (RHR) recorded by electrocardiogram after 10 minutes' rest and medication usage within 1 month were recorded at baseline. RHR less than 70 beats per minute (bpm) was regarded as well controlled. β-receptor blockers and (or) ivabradine would be added in patients whose RHR were over 70 bpm. RHR after optimized medication adjustment was recorded during follow-up period. Results: One hundred and fifty patients were included in this study with average RHR (80.6±11.9) bpm. RHR was<70 bpm in 27.3% (41/150) patients at baseline and β-receptor blockers was underused in 80.7% patients (88/109) whose RHR was>70 bpm. The overall RHR decreased to (73.1±10.4) bpm and percent of patients with RHR<70 bpm increased to 70.0% (105/150) after up-titration of β-receptor blockers compared to baseline (χ2=52.958, P<0.001). Ivabradine was added in the rest 45 patients and RHR was<70 bpm in 43 out of 45 patients after ivabradine use. The overall RHR decreased to (67.1±2.7) bpm and percent of RHR<70 bpm significantly increased to 98.7% (148/150) (χ2=44.504, P<0.001 vs. up-titration of β-receptor blockers only). Conclusion: RHR in CHF patients who received CIED therapy is not ideally controlled in this patient cohort, individual up-titration ofβ-receptor blockers and ivabradine use may help to optimize RHR in these patients.
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Affiliation(s)
- Y Gao
- Department of Cardiology, General Hospital of Shenyang Military Region, Shenyang 110016, China
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Chen YZ, Bai N, Bi JH, Liu XW, Xu GQ, Zhang LF, Li XQ, Huo R. Propranolol inhibits the proliferation, migration and tube formation of hemangioma cells through HIF-1α dependent mechanisms. ACTA ACUST UNITED AC 2017; 50:e6138. [PMID: 28977119 PMCID: PMC5625545 DOI: 10.1590/1414-431x20176138] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 08/15/2017] [Indexed: 12/11/2022]
Abstract
The aim of this study was to investigate the mechanism of propranolol on the regression of hemangiomas. Propranolol-treated hemangioma tissues were collected and the expression of hypoxia inducible factor-1α (HIF-1α) was examined. We also established HIF-1α overexpression and knockdown hemangioma cells, and determined the effects of HIF-1α on the hemangioma cells proliferation, apoptosis, migration and tube formation. Significantly increased HIF-1α level was found in the hemangioma tissues compared to that in normal vascular tissues, whereas propranolol treatment decreased the HIF-1α level in hemangioma tissues in a time- and dose-dependent manner. Moreover, propranolol treatment significantly decreased cell proliferation, migration and tube formation as well as promoted cell apoptosis in HIF-1α overexpression and knockdown hemangioma cells. Propranolol suppressed the cells proliferation, migration and tube formation of hemangioma cells through HIF-1α dependent mechanisms. HIF-1α could serve as a novel target in the treatment of hemangiomas.
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Affiliation(s)
- Y Z Chen
- Department of Aesthetic, Plastic, and Burn Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China.,Department of Aesthetic, Plastic, and Burn Surgery, Linyi People's Hospital, Linyi, Shandong, China
| | - N Bai
- Department of Aesthetic, Plastic, and Burn Surgery, Linyi People's Hospital, Linyi, Shandong, China
| | - J H Bi
- Department of Aesthetic, Plastic, and Burn Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - X W Liu
- Department of Aesthetic, Plastic, and Burn Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - G Q Xu
- Department of Aesthetic, Plastic, and Burn Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - L F Zhang
- Department of Aesthetic, Plastic, and Burn Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - X Q Li
- Department of Aesthetic, Plastic, and Burn Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - R Huo
- Department of Aesthetic, Plastic, and Burn Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
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Chen ZX, Xi YJ, Huang L, Li WC, Li R, Xu GQ, Cheng HS. A novel surface modification scheme for ITO nanocrystals by acetylene: a combined experimental and DFT study. Phys Chem Chem Phys 2015; 17:26740-4. [DOI: 10.1039/c5cp05093f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The chemisorption of C2H2 molecules on the ITO(100) surface results in ethylene-like configurations as studied by DFT and experiment.
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Affiliation(s)
- Z. X. Chen
- Department of Chemistry
- National University of Singapore
- Singapore 117543
- Singapore
| | - Y. J. Xi
- Department of Chemistry
- National University of Singapore
- Singapore 117543
- Singapore
| | - L. Huang
- Sustainable Energy Laboratory
- China University of Geosciences Wuhan
- Wuhan 430074
- China
- Department of Chemical and Petroleum Engineering
| | - W. C. Li
- Department of Chemistry
- National University of Singapore
- Singapore 117543
- Singapore
| | - R. Li
- Department of Chemistry
- National University of Singapore
- Singapore 117543
- Singapore
| | - G. Q. Xu
- Department of Chemistry
- National University of Singapore
- Singapore 117543
- Singapore
| | - H. S. Cheng
- Sustainable Energy Laboratory
- China University of Geosciences Wuhan
- Wuhan 430074
- China
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Abstract
We present a new mechanism--discovered using molecular dynamics simulations--that leads to complete healing of nanocracks. This mechanism relies on the generation of crystal defects known as disclinations by migrating grain boundaries. Crack healing by disclinations does not require any compressive loads applied normal to the crack faces and even occurs under monotonic tensile loading. By closing small cracks and suppressing the propagation of others, this mechanism may provide a novel way of mitigating internal damage that influences ductility in nanocrystalline metals.
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Affiliation(s)
- G Q Xu
- Department of Materials Science and Engineering, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA
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Affiliation(s)
| | - G. Q. Xu
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3,
117543, Singapore
| | - S. G. Ang
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3,
117543, Singapore
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Abstract
Geese form a fatty liver after feeding on a carbohydrate-rich diet, possibly as an evolutionary adaptation to accumulate reserves for migration. To gain insight into the gene-regulation processes of hepatic steatosis in geese, we examined the profile of transcriptional expression in goose fatty liver and control liver by suppression subtractive hybridization and measured the levels of serum biochemical variables. We found 107 genes whose expression was different between the treatment and control groups. The main functions of these genes are metabolic processes, including the metabolism of carbohydrates, amino acids, and lipids. Twenty-four genes were classified using the Kyoto Encyclopaedia of Genes and Genomes pathways. Twelve genes that related to metabolic and cellular processes were confirmed by quantitative RT-PCR. A specific positive effect of feeding was observed on the expression of genes involved mainly in unsaturated fatty acids and triglyceride synthesis, and a negative effect was observed on genes involved in β-oxidation, cholesterol metabolism, and glycolysis. The results could serve as an important reference for the development of goose breeding for fatty liver production and human liver disease research.
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Affiliation(s)
- L H Zhu
- College of Animal Science and Technology, Yangzhou University, Yangzhou, P. R. China
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Zhang YP, Yong KS, Xu GQ, Gao XY, Wang XS, Wee ATS. Molecular anchor Cu-S formed on a thiophene mediated Si(111)-(7x7) surface. J Chem Phys 2008; 128:044706. [PMID: 18247980 DOI: 10.1063/1.2822149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Thiophene molecule selectively binds to the adjacent adatom-rest atom pair on the Si(111)-(7x7) surface through its alpha-carbon atoms, leading to the covalent attachment of a C-S-C linkage and remaining C=C (beta-carbon) bond onto the surface. Photoemission studies show that Cu atom readily adsorbs onto the S atom of the functional group to form the Cu-S molecular anchor in two forms: one points away from the thiophene C=C group; the other points toward the C=C group.
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Affiliation(s)
- Y P Zhang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
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Goh HW, Goh SH, Xu GQ, Lee KY, Yang GY, Lee YW, Zhang WD. Optical Limiting Properties of Double-C60-End-Capped Poly(ethylene oxide), Double-C60-End-Capped Poly(ethylene oxide)/Poly(ethylene oxide) Blend, and Double-C60-End-Capped Poly(ethylene oxide)/Multiwalled Carbon Nanotube Composite. J Phys Chem B 2003. [DOI: 10.1021/jp027726x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- H. W. Goh
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore, DSO National Laboratories, 20 Science Park Drive, Singapore 118230, Singapore, and Institute of Material Research and Engineering, National University of Singapore, Research Link, Singapore 117602, Singapore
| | - S. H. Goh
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore, DSO National Laboratories, 20 Science Park Drive, Singapore 118230, Singapore, and Institute of Material Research and Engineering, National University of Singapore, Research Link, Singapore 117602, Singapore
| | - G. Q. Xu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore, DSO National Laboratories, 20 Science Park Drive, Singapore 118230, Singapore, and Institute of Material Research and Engineering, National University of Singapore, Research Link, Singapore 117602, Singapore
| | - K. Y. Lee
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore, DSO National Laboratories, 20 Science Park Drive, Singapore 118230, Singapore, and Institute of Material Research and Engineering, National University of Singapore, Research Link, Singapore 117602, Singapore
| | - G. Y. Yang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore, DSO National Laboratories, 20 Science Park Drive, Singapore 118230, Singapore, and Institute of Material Research and Engineering, National University of Singapore, Research Link, Singapore 117602, Singapore
| | - Y. W. Lee
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore, DSO National Laboratories, 20 Science Park Drive, Singapore 118230, Singapore, and Institute of Material Research and Engineering, National University of Singapore, Research Link, Singapore 117602, Singapore
| | - W.-D. Zhang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore, DSO National Laboratories, 20 Science Park Drive, Singapore 118230, Singapore, and Institute of Material Research and Engineering, National University of Singapore, Research Link, Singapore 117602, Singapore
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Goh HW, Goh SH, Xu GQ. Hydrogen bonding and hydrophobic interactions between [60]fullerenated poly(2-hydroxyethyl methacrylate) and poly(1-vinylimidazole) or poly(4-vinylpyridine). ACTA ACUST UNITED AC 2002. [DOI: 10.1002/pola.10522] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Dixon-Warren SJ, Polanyi JC, Stanners CD, Xu GQ. Photoinduced charge-transfer dissociation of hydrogen halides on silver and potassium. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100378a011] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Cho CC, Collings BA, Hammer RE, Polanyi JC, Stanners CD, Wang JH, Xu GQ. Photoinduced charge-transfer dissociation of hydrogen chloride on silver(111). ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100360a008] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
The covalent binding of acrylonitrile (CH(2)=CH-C triple bond N) and the formation of a C=C-C=N structure on Si(100) have been investigated using high-resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and density functional theory (DFT) calculations. For chemisorbed acrylonitrile, the absence of nu(C triple bond N) at 2245 cm(-1) and the appearance of nu(C=N) at 1669 cm(-1) demonstrate that the cyano group directly participates in the interaction with Si(100), which is further supported by XPS and UPS observations. Our experimental results and DFT calculations unambiguously demonstrate a [2 + 2] cycloaddition mechanism for acrylonitrile chemisorption on Si(100) through the binding of C triple bond N to Si dimers. The resulting chemisorbed monolayer with a C=C-C=N skeleton can serve as a precursor for further chemical syntheses of multilayer organic thin films in a vacuum and surface functionalization for in situ device fabrication.
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Affiliation(s)
- F Tao
- Department of Chemistry, National University of Singapore, 10 Kent Ridge, Singapore 119260
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Hu YF, Sham TK, Zou Z, Xu GQ, Chan L, Yates BW, Bancroft GM. A study of titanium nitride diffusion barriers between aluminum and silicon by X-ray absorption spectroscopy: the Si, Ti and N results. J Synchrotron Radiat 2001; 8:860-862. [PMID: 11512957 DOI: 10.1107/s0909049500018252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2000] [Accepted: 11/22/2000] [Indexed: 05/23/2023]
Abstract
We report a multi-elment, multi-edge and multi-detection mode X-ray photoabsorption study of a series of Al/TiN(x)/Si(100) thin films as a function of the TiN(x) film thickness (100A-500A) and of the annealing temperature (400 degrees C-600 degrees C). The Si K- and L-edge results show that Si does not diffuse to the surface for all the films. The high resolution Ti L-edge and N K-edge spectra show that the TiN(x) layer undergoes a dramatic chemical reaction with the gradual increase in the annealing temperature. This chemical reaction stabilizes at 560 degrees C at which the TiN(x) film is known to fail to act as an effective diffusion barrier between Al and Si.
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Affiliation(s)
- Y F Hu
- Canadian Synchrotron Radiation Facility, University of Wisconsin-Madison, 53589, USA.
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Li HB, Chen F, Zhang TY, Yang FQ, Xu GQ. Preparative isolation and purification of lutein from the microalga chlorella vulgaris by high-speed counter-current chromatography. J Chromatogr A 2001; 905:151-5. [PMID: 11206781 DOI: 10.1016/s0021-9673(00)00987-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
High-speed counter-current chromatography (HSCCC) was applied to the isolation and purification of lutein from microalgae. Analytical HSCCC was used for the preliminary selection of a suitable solvent system composed of n-hexane-ethanol-water (4:3:1, v/v). Using the above solvent system, preparative HSCCC was successfully performed yielding lutein at 98% purity from 200 mg of the crude extract in a one-step separation.
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Affiliation(s)
- H B Li
- Department of Botany, The University of Hong Kong, China
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Affiliation(s)
- M. H. Qiao
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore, and Department of Chemistry, Fudan University, Shanghai 200433, People's Republic of China
| | - Y. Cao
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore, and Department of Chemistry, Fudan University, Shanghai 200433, People's Republic of China
| | - F. Tao
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore, and Department of Chemistry, Fudan University, Shanghai 200433, People's Republic of China
| | - Q. Liu
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore, and Department of Chemistry, Fudan University, Shanghai 200433, People's Republic of China
| | - J. F. Deng
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore, and Department of Chemistry, Fudan University, Shanghai 200433, People's Republic of China
| | - G. Q. Xu
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore, and Department of Chemistry, Fudan University, Shanghai 200433, People's Republic of China
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Cao Y, Wang Z, Deng JF, Xu GQ. Evidence for Dangling Bond Mediated Dimerization of Furan on the Silicon (111)-(7x7) Surface This work was supported by the National University of Singapore (grant no. 3970612). Angew Chem Int Ed Engl 2000; 39:2740-2743. [PMID: 10934412 DOI: 10.1002/1521-3773(20000804)39:15<2740::aid-anie2740>3.0.co;2-j] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Y Cao
- Department of Chemistry, Fudan University Shanghai 200433 (China)
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Affiliation(s)
- Y. Cao
- Department of Chemistry, National University of Singapore, 10 Kent Ridge, Singapore 119260; Department of Chemistry, Fudan University, Shanghai, 200433, P.R.C.; and Department of Chemistry, Princeton University, Princeton, New Jersey 08544-1009
| | - X. M. Wei
- Department of Chemistry, National University of Singapore, 10 Kent Ridge, Singapore 119260; Department of Chemistry, Fudan University, Shanghai, 200433, P.R.C.; and Department of Chemistry, Princeton University, Princeton, New Jersey 08544-1009
| | - W. S. Chin
- Department of Chemistry, National University of Singapore, 10 Kent Ridge, Singapore 119260; Department of Chemistry, Fudan University, Shanghai, 200433, P.R.C.; and Department of Chemistry, Princeton University, Princeton, New Jersey 08544-1009
| | - Y. H. Lai
- Department of Chemistry, National University of Singapore, 10 Kent Ridge, Singapore 119260; Department of Chemistry, Fudan University, Shanghai, 200433, P.R.C.; and Department of Chemistry, Princeton University, Princeton, New Jersey 08544-1009
| | - J. F. Deng
- Department of Chemistry, National University of Singapore, 10 Kent Ridge, Singapore 119260; Department of Chemistry, Fudan University, Shanghai, 200433, P.R.C.; and Department of Chemistry, Princeton University, Princeton, New Jersey 08544-1009
| | - S. L. Bernasek
- Department of Chemistry, National University of Singapore, 10 Kent Ridge, Singapore 119260; Department of Chemistry, Fudan University, Shanghai, 200433, P.R.C.; and Department of Chemistry, Princeton University, Princeton, New Jersey 08544-1009
| | - G. Q. Xu
- Department of Chemistry, National University of Singapore, 10 Kent Ridge, Singapore 119260; Department of Chemistry, Fudan University, Shanghai, 200433, P.R.C.; and Department of Chemistry, Princeton University, Princeton, New Jersey 08544-1009
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Zou Z, Hu YF, Sham TK, Huang HH, Xu GQ, Seet CS, Chan L. XAFS studies of Al/TiNx films on Si(100) at the Al K- and L3,2-edge. J Synchrotron Radiat 1999; 6:524-525. [PMID: 15263367 DOI: 10.1107/s0909049599001247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/1998] [Accepted: 01/22/1999] [Indexed: 05/24/2023]
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Affiliation(s)
- H. H. Huang
- Chemistry Department, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
| | - Z. Zou
- Chemistry Department, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
| | - X. Jiang
- Chemistry Department, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
| | - W. Y. Chan
- Chemistry Department, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
| | - G. Q. Xu
- Chemistry Department, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
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Huang HH, Sreekanth CS, Seet CS, Xu GQ, Chan L. Thermal and Photoinduced Desorption and Decomposition of Fe(CO)5 on Clean and Oxygen-Modified Ru(001). ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp961174z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- H. H. Huang
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
| | - C. S. Sreekanth
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
| | - C. S. Seet
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
| | - G. Q. Xu
- Department of Chemistry, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
| | - L. Chan
- Chartered Semiconductor Manufacturing Pte. Ltd., 60 Woodlands Industrial Park D, Street 2, Singapore 738406
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Zhang SL, Zhou CT, Cao HK, Xu GQ. [Analysis of the clinic with pathology and detection using IGSS of 201 cases of discoid lupus erythematosus]. Shanghai Kou Qiang Yi Xue 1996; 5:132-4. [PMID: 15160001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Clinic pathology and detection using IGSS of 201 cases of discoid lupus erythematosus (DLE) were studied in this paper.The results showed:1.DLE usually occured on the low lip(60%);2.Suffering from gastrointestinal disease were the first symptom(25%DLE cases was confirmed by mild dysplasia,3 cases of carcinoma.1 cases Combined of DLE and lichen planus(LP);4.Immunogold-silver Staining (IGSS) was applied to detect immune complex.The result indicated that Fg,immunoglobins and complement C3 deposited at basal membrane zone of DLE.It is illustrated that DLE is an autoimmune disease which is caused by many kinds of factors and may be cancerous.Coexistence of DLE and LP suggested that they may be at different stages of the same disease.Its mechanism will be further studied.
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Affiliation(s)
- S L Zhang
- Department of Oral Medicine, Ninth People's Hospital, School of Stomatology, Shanghai Second Medical University. Shanghai 200011,China
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Xu GQ, Yamano T, Shimada M. Copper distribution in fetus and placenta of the macular mutant mouse as a model of Menkes kinky hair disease. Biol Neonate 1994; 66:302-10. [PMID: 7873696 DOI: 10.1159/000244121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Menkes kinky hair disease (MKHD) in humans is caused by a disturbance in copper homeostasis. A mutant mouse shows clinical and biochemical features very close to MKHD. In an attempt to elucidate the defect in copper transport, the copper distribution in various organs of 18-gestational-day-old macular mouse embryos, following administration by a single injection of saline (control) or 50 micrograms of CuCl2 on day 16 of gestation or by two injections on days 15 and 17 of gestation to the dams, was examined both biochemically and histochemically. The copper content in the hemizygous fetus (Ml/y) born to the homozygous mother, who had no copper injection during gestation, was lower in the brain and liver but higher in the placenta than in the respective organs of the normal fetus. When 50 micrograms of CuCl2 was injected into heterozygous dams (Ml/+) on day 16 of gestation, their hemizygous fetuses showed a slight increase in the copper content in the brain and liver, but the amount of copper in these organs was still less than that of the normal fetus. Conversely, the copper content in the placenta of the hemizygous fetus was far higher than that of the normal fetus. In the copper staining of the fetuses harvested from heterozygous dams, some fetuses showed copper deposition in the placenta, but not in the liver. The others showed no copper deposit in both the placenta and liver, thus indicating that the former were hemizygous for the mutation and the latter were normal littermates.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- G Q Xu
- Department of Pediatrics, Shiga University of Medical Science, Japan
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Abstract
Five deletion mutants of the D/E linker region of the troponin C central helix were tested for conformational and functional differences from wild-type troponin C. The mutants were in the region 87KEDAKGKSEEE97: dEDA, dKG, dKGK, dKEDAKGK, and dSEEE, designed to change the length of the central helix and the orientation of the Ca(2+)-binding domains relative to each other [Dobrowolski, Z., Xu, G.-Q., & Hitchcock-DeGregori, S.E. (1991) J. Biol. Chem. 266, 5703-5710]. Previous work showed that all mutants except dSEEE are partially defective in one part of the Ca2+ switch or the other. All mutants undergo Ca(2+)-dependent conformational changes as detected by changes in electrophoretic mobility, alpha-helix content, and hydrophobic exposure. Deletions of the central helix do not extensively alter the thermal stability of troponin C, as determined by temperature-dependent loss of alpha-helix. There are differences among the mutants that do not correlate with function. All troponin C mutants show Ca(2+)-dependent interaction with troponin I and T in polyacrylamide gels. Troponin I-troponin C interaction was also analyzed by Ca(2+)-dependent increase in the monomer/excimer ratio of tropinin I and relief of inhibition of the actomyosin S1 ATPase. While all mutants retain basic function, dKGK, dKEDAKGK, and dEDA have altered interaction with troponin I in the absence of Ca2+. dSEEE differs in conformation from wild type, but it is normal in functional assays. This conserved region of the D/E linker is not required for interaction with troponin I in the presence or absence of urea.
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Affiliation(s)
- Z Dobrowolski
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway 08854
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Xu GQ, Xi NZ, Chen GS, Jiang XG, Xu HN. [Effect of enhancers on cutaneous permeation of piroxicam in vitro]. Zhongguo Yao Li Xue Bao 1991; 12:235-8. [PMID: 1781286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Enhancing effects on the permeation of piroxicam (Pir) through excised hairless mouse (inbred HRS mice) skin were investigated by measuring flux. Azone 1% was found to be the most effective enhancer studied, increasing the flux about 21 times. The effect of Azone was enhanced by the presence of propylene glycol. Oleic acid, ethylacetate, and ethanol promoted the diffusion of Pir. Other enhancers, such as DMSO, PEG 400, acetone, urea and salicylic acid, showed little or no effect. Pir-beta-cyclodextrin inclusion compound increased the flux about 3 times. The results revealed that lipophilic enhancers were more effective than lipophobic ones.
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Affiliation(s)
- G Q Xu
- Division of Biopharmaceutics, Shanghai Medical University, China
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Dobrowolski Z, Xu GQ, Hitchcock-DeGregori SE. Modified calcium-dependent regulatory function of troponin C central helix mutants. J Biol Chem 1991; 266:5703-10. [PMID: 1826002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Mutations have been made in the exposed region of the avian troponin C central helix, the D/E linker, which change its length and the orientation of the Ca2(+)-binding domains relative to each other. The region 87Glu-Asp-Ala-Lys-Gly-Lys-Ser-Glu-Glu-Glu97 has been altered in five deletion (d) mutants: dEDA, dKG, dKGK, dSEEE, and dKEDAKGK. The recombinant troponin Cs were expressed in Escherichia coli, purified, and assayed for function. All mutants retained basic troponin C function. They all bound Ca2+ to the low and high affinity sites, and they all were able to confer Ca2+ sensitivity on the regulated actomyosin ATPase. However, the regulatory function of all mutants except dSEEE was defective in one part of the Ca2+ switch or the other. In certain conditions dKGK and dKEDAKGK failed to inhibit fully whereas dEDA and dKG failed to activate the regulated actomyosin ATPase fully. The following general conclusions have been made. (a) The length of the D/E linker per se (assuming the linker is helical) and the orientation of the two Ca2(+)-binding domains relative to each other are not crucial for regulation. (b) The conserved charge cluster 95Glu-Glu-Glu97, in a region of troponin C known to bind to troponin I and postulated to be required for regulation, appears to be unimportant for function. (c) Deletion of 88Glu-Asp-Ala90 resulted in a troponin C that could not activate the actomyosin (or S1) ATPase over the level of actomyosin alone, thus defining a role for troponin C in this aspect of thin filament regulation. The results have been interpreted in terms of the crystallographic structure of troponin C and related to results with analogous calmodulin mutants.
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Affiliation(s)
- Z Dobrowolski
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway 08854
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Xu GQ, Hitchcock-DeGregori SE. Synthesis of a troponin C cDNA and expression of wild-type and mutant proteins in Escherichia coli. J Biol Chem 1988; 263:13962-9. [PMID: 2971047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
An avian fast striated muscle troponin C cDNA was designed and synthesized from six oligonucleotides using the overlap-fill in method and overproduced in Escherichia coli for the purpose of developing recombinant DNA approaches to study structure-function relationships in this calcium-binding regulatory protein. The recombinant protein isolated from E. coli functions as a bona fide troponin C in all properties that were assayed: calcium binding, calcium-dependent conformational change, calcium-dependent interaction with troponin I, and formation of a functional ternary complex with troponin I and troponin T that can confer calcium sensitivity on the actomyosin MgATPase. The initiating methionine was removed by E. coli leaving alanine as the first amino acid, as in the muscle troponin C. The first amino acid was not acetylated, but this difference from the muscle protein has no apparent effect on the function. The presence of Glu at position 99, as in turkey, versus Ala in chicken resulted in no detectable difference in comparing recombinant with chicken troponin C. A mutant in which residues 91-93 (Lys-Gly-Lys) in the D/E helical linker were deleted differs in function from wild-type troponin C in the conformational change that takes place upon calcium binding and its interaction with troponin I. Also, the mutant troponin C is impaired in its ability to form a functional complex with troponin I and troponin T that will confer calcium sensitivity on the actomyosin MgATPase.
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Affiliation(s)
- G Q Xu
- Department of Anatomy, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway 08854
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Holland RJ, Xu GQ, Levkoff J, Robertson A, Bernasek SL. Experimental studies of the dynamics of nitrogen van der Waals cluster scattering from metal surfaces. J Chem Phys 1988. [DOI: 10.1063/1.454252] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Xu GQ, Zou CL, Tsou CL. The cooperative behavior of yeast D-glyceraldehyde-3-phosphate. Dehydrogenase as studied by the formation of the fluorescent NAD derivative. Sci Sin B 1984; 27:800-10. [PMID: 6505672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The ultraviolet irradiation of the yeast D-glyceraldehyde-3-phosphate dehydrogenase carboxymethylated at the active site Cys residues, as with the rabbit muscle enzyme, led to the formation of a fluorescent NAD derivative with an emission maximum at 410 nm. Similar results were obtained with the enzyme selectively carboxymethylated at only 2 of its 4 active site Cys residues. The binding of NAD+ to both the carboxymethylated enzymes is non-cooperative or only weakly negatively cooperative when determined by NAD+ quenching of the intrinsic protein fluorescence. However, determinations of the amount of fluorescent NAD derivative formed under different NAD+ concentrations show that both the carboxymethylated enzymes appeared to bind NAD+ with positive cooperativity as in the case of the binding of NAD+ to the native apoenzyme. This seems to suggest that the spatial positioning of the nicotinamide moiety at the active site of the irradiated enzyme resembles more closely that of the nicotinamide ring in the native holoenzyme as compared to the carboxymethylated enzymes.
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Tsou CL, Xu GQ, Zhou JM, Zhao KY. A new fluorescent probe for the study of the allosteric properties of D-glyceraldehyde 3-phosphate dehydrogenase. Biochem Soc Trans 1983; 11:425-9. [PMID: 6352362 DOI: 10.1042/bst0110425] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Xu GQ. [Analysis of trace elements in the hair of patients with lichen planus and leukoplakia]. Zhonghua Kou Qiang Ke Za Zhi 1983; 18:5-8. [PMID: 6575903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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