351
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Liu D, Zheng C, Chen Q, Zhang Z, Wu Y, Wang R, Ling J. [Coexisting pheochromocytoma and renal artery stenosis]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1998; 36:295-6. [PMID: 11825392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To improve the diagnosis of coexisting pheochromocytoma and renal artery stenosis. METHOD Four patients with coexisting pheochromocytoma and renal artery stenosis were treated. RESULT After removal of the pheochromocytoma, the blood pressure became normal in two patients combined with resection of kidney with renal artery stenosis, and one patient with local adhesion loosened. The hypertension, however, persisted in another patient after the resection of pheochromocytoma even though the long segment of renal artery stenosis was relieved. CONCLUSION After pheochromocytoma was diagnosed with its known position, coexisting renal artery stenosis should be suspected according to one of the following conditions: (1) Vascular murmurs are noted at the area of the upper abdomen or back; (2) One of the kidneys becomes less sized; (3) Using the inhibitor of receptor alpha only has no effect lowering blood pressure and it is necessary to add the inhibitor of angiotension; (4) Postoperative hypertension does not resolve when no remaining pheochromocytoma is present. the renal artery stenosis can be reversed after both removal of pheochromocytoma and loosening of adhesion in case of stenosis due to the pressure of the tumor and adhesion caused renal artery angling and local stricture. Extensive stenosis or closure, however, can not be corrected with severe atrophy of renal parenchyma due to pheochromocytoma, and the resection of kidney should be indicated.
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352
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Zhang J, Zheng C. [Bispectral analysis of EEG signal during focal cerebral ischemia]. HANG TIAN YI XUE YU YI XUE GONG CHENG = SPACE MEDICINE & MEDICAL ENGINEERING 1998; 11:97-101. [PMID: 11543237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Early noninvasive detection of cerebral ischemia is important for fighter pilots as well as in clinical diagnosis. In this paper, a model of focal cerebral ischemia was presented. Bispectrum of EEG signals recorded from ischemic region and normal region after 30 min ischemia was analyzed using the third-order recursion method, which possesses higher frequency resolving ability. It can resolve two closely spaced peaks in the bispectrum and detect the presence or absence of quadratic phase coupling at frequency pairs that are very close to each other. It was found that some characteristics of such bispectrum are very sensitive to focal cerebral ischemia. The maximum bispectrum magnitude of EEG and the weighted center of bispectrum (WCOB) changed sensitively to the different ischemic regions and ischemic stages. The ischemic and normal regions as well as the degree of ischemia can be clearly distinguished by analyzing their bispectrum of EEG. It demonstrates that this method can be used as a quantitative method for the detection of focal cerebral ischemia in the early phase.
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353
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Chen Z, Zheng C, Feng Y, Hofmann H. Local bubble behavior in three-phase fluidized beds. CAN J CHEM ENG 1998. [DOI: 10.1002/cjce.5450760220] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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354
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Cao X, Jiang D, Zheng C. [Studies on trigonometric transform enhancement of chest radiograph based on its anatomical feature]. ZHONGGUO YI LIAO QI XIE ZA ZHI = CHINESE JOURNAL OF MEDICAL INSTRUMENTATION 1998; 22:92-97. [PMID: 12016837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this paper, we present a novel trigonometric transform contrast enhancement method for digital chest radiograph, which is based on the anatomical feature of the image processed. With automatic segmenting chest image into a lung region and a non-chest region, a positive linear transform and a negative one are used in lung region and the other region respectively. Therefore, it can enhance the contrast both in lung regions and in mediastinum region up to entire dynamic range of display device.
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355
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He X, Kuijpers GA, Goping G, Kulakusky JA, Zheng C, Delporte C, Tse CM, Redman RS, Donowitz M, Pollard HB, Baum BJ. A polarized salivary cell monolayer useful for studying transepithelial fluid movement in vitro. Pflugers Arch 1998; 435:375-81. [PMID: 9426293 DOI: 10.1007/s004240050526] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
There are no reported, convenient in vitro models for studying polarized functions in salivary epithelial cells. Accordingly, we examined three often-used salivary cell lines for their ability to form a polarized monolayer on permeable, collagen-coated polycarbonate filters. Only the SMIE line, derived from rat submandibular gland, had this ability. The SMIE cell monolayer exhibited junctional complexes, with a tight-junction-associated protein, ZO-1, localized to cell-cell contact areas. The Na+/K+-ATPase alpha1-subunit was detected predominantly in the basolateral membranes, while the Na+/H+ exchanger isoform 2 appeared primarily in the apical membranes. Using adenovirus-mediated cDNA transfer, SMIE cells were shown to be capable of routing marker proteins (beta-galactosidase +/- a nuclear targeting signal, alpha1-antitrypsin, aquaporin-1) to appropriate locations. Furthermore, this salivary cell monolayer provided a convenient tool for studying aquaporin-1-mediated, osmotically directed, transepithelial fluid movement in vitro. Thus, SMIE cells appear to be a useful experimental model with which to study some polarized functions in a salivary epithelial cell line.
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356
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Zheng C, Xing Z, Bian ZC, Guo C, Akbay A, Warner L, Guan JL. Differential regulation of Pyk2 and focal adhesion kinase (FAK). The C-terminal domain of FAK confers response to cell adhesion. J Biol Chem 1998; 273:2384-9. [PMID: 9442086 DOI: 10.1074/jbc.273.4.2384] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Pyk2 is a recently described cytoplasmic tyrosine kinase that is related to focal adhesion kinase (FAK) and can be activated by a variety of stimuli that elevate intracellular calcium. In this report, we showed that Pyk2 and FAK tyrosine phosphorylation are regulated differentially by integrin-mediated cell adhesion and soluble factors both in rat aortic smooth muscle cells, which express endogenous Pyk2 and FAK, and in transfected Chinese hamster ovary cells. We also found that Pyk2 is diffusely present throughout the cytoplasm, while FAK is localized in focal contacts as expected, suggesting that the different localization may account for their differential regulation. By analyzing a chimeric protein contain N-terminal and kinase domains of Pyk2 and C-terminal domain of FAK, we provided evidence that the distinctive C-terminal domains of Pyk2 and FAK were responsible for their differential regulation by integrins and soluble stimuli as well as their subcellular localization. Finally, we correlated FAK, Pyk2, and the chimeric protein binding to talin, but not paxillin, with their regulation by integrins and focal contact localization. These results demonstrate that the distinctive C-terminal domain of Pyk2 and FAK confer their differential regulation by different subcellular localization and association with the cytoskeletal protein talin.
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357
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Zheng C, Feng G, Yang J, Liang H, Tian Z. Renal angiomyolipoma: diagnosis with B-ultrasonography, CT scanning, DSA and its interventional treatment. JOURNAL OF TONGJI MEDICAL UNIVERSITY = TONG JI YI KE DA XUE XUE BAO 1997; 16:241-4, 252. [PMID: 9389091 DOI: 10.1007/bf02888116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
From 1989, 15 cases of renal angiomyolipoma (AML) have been diagnosed by ultrasonography. CT scanning and digital subtraction angiography (DSA) at our hospital. In 8 patients with uneven hyperechoes on B-mode ultrasonography (B-US) (8/15) and 7 with low density of fat on CT scanning (7/12) accurate diagnosis was established preoperatively. DSA revealed the "berry-like" pseudoaneurysms in the arterial phase (14 cases), the defined lucent area in the nephrogram phase (10 cases) and the "onion-peel appearances" during venous phases (8 cases), correct diagnosis was achieved in all patients. 8 cases were surgically treated and 7 treated by subselective embolization of renal artery. Effects in all cases were good. The diagnostic value of B-US, CT scanning, DSA and interventional treatment of AML was discussed. It was believed that the diagnosis with DSA was a technique with high specificity, and embolization therapy was simple and effective for AML.
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358
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Zheng C, Liu Y, Chang C. [Doppler echocardiographic studies on the fetal cardiac function in intrauterine growth retardation]. ZHONGHUA FU CHAN KE ZA ZHI 1997; 32:725-7. [PMID: 9772435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
OBJECTIVE To assess fetal cardiac function by Doppler echocardiography in intrauterine growth retardation (IUGR). METHODS We investigated the changes in cardiac function in 64 normal fetuses and 36 fetuses with IUGR. Blood flow velocity waveforms were obtained from the aorta, pulmonary artery and atrioventricular valves. The following variables were measured: peak flow velocity (PFV), mean velocity (V), accelerate time (ACT), systolic volume (SV) and cardiac output (CO) represented the systolic function; the peak early flow velocity (PFVe), peak late flow velocity (PFVa), PFVe/PFVa (E/A), mean velocity (V) of mitral or tricuspid valve represented the diastolic function. RESULTS In normal fetuses, the PFV, V, ACT of aorta were all greater than those of pulmonary artery, whereas SV, CO in left ventricle were smaller. The PFVe, PFVa in mitral valve were smaller than those of tricuspid valve. In IUGR fetuses, the PFV, V, SV, CO of aorta or pulmonary artery were significantly lower than those of normal. The ACT in pulmonary artery decreased significantly, but increased in aortic artery. The SV, Co of left ventricle were greater than those of righ ventricle. The E/A of mitral and tricuspid valve, PFVe, PFVa, V of tricuspid valve were all decreased. The PFVe, PFVa in mitral valve were greater than those of tricuspid valve. CONCLUSIONS The changes of cardiac function in IUGR are probably caused by "brain sparing", which means a redistribution of cardiac flow after hypoxia.
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359
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Feng G, Kramann B, Zheng C, Zhou R. [Comparative study on the long-term effect of permanent embolization of hepatic artery with Bletilla striata in patients with primary liver cancer]. JOURNAL OF TONGJI MEDICAL UNIVERSITY = TONG JI YI KE DA XUE XUE BAO 1997; 16:111-6. [PMID: 9324524 DOI: 10.1007/bf02887970] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
From May, 1990 to Sept., 1993 106 cases of primary liver cancer were treated by temporary or permanent hepatic arterial embolization with Bletilla striata powders (permanent, 56 cases) or gelfoam powders (temporary, 50 cases) under controlled technical conditions, in term of degree of tumor necrosis, revascularization of tumor, and long-term effect, the results of Bletilla striata group were better as compared with those of gelfoam group. The 1, 2 and 3 year survival rates were 44.9%, 33.6% and 33.6% in Beltilla striata group while the rates were 48.9%, 31.1% and 16.0% in gelfoam group, suggesting that Bletilla striata is superior to gelfoam as an embolizing agent for hepatic carcinoma.
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360
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Zheng C, Huang Y, Pan X, Ji L. [Pharmacognostical identification of Anoectochilus roxburghii]. ZHONG YAO CAI = ZHONGYAOCAI = JOURNAL OF CHINESE MEDICINAL MATERIALS 1997; 20:552-4. [PMID: 12572511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
This paper reported the pharmacognostical identification on characters, microscopic characteristics and TLC of the Anoectochilus roxburghii (Wall.) Lindl., and compared with different resouce samples. The results may provide reference for its identification.
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361
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Zhou K, Shang C, Liu C, Zheng C. [An experimental study on regeneration device for urine and waste water in space station]. HANG TIAN YI XUE YU YI XUE GONG CHENG = SPACE MEDICINE & MEDICAL ENGINEERING 1997; 10:323-7. [PMID: 11540382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The principle, structure and function of the regeneration system for urine and waste water treatment were introduced. The experimental results demonstrated that, the treatment capacity was 1.2-1.9 kg/h, and the regeneration efficiency exceeded 92%. The quality of the treated water were: TOC < 20 g/m3, (NH3 + NH4+) < 10 g/m3, electric conductivity < 100 micro s/cm, pH= 6-8.
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362
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Zheng C, Peyton D, Breslow E. Modulation of dimerization by residues distant from the interface in bovine neurophysin-II. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1997; 50:199-209. [PMID: 9309584 DOI: 10.1111/j.1399-3011.1997.tb01186.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The crystal structure of bovine neurophysin-II in its liganded state (Chen et al. [1991] Proc. Natl. Acad. Sci. USA 88, 4240-4244) indicates that the 1-6 sequence has a disordered conformation, lacks noncovalent contacts to other regions of the protein and is distant from the monomer-monomer interface. Cleavage of the 1-6 sequence by Staphylococcus protease V8 yielded a protein that, for the first time, crystallized in both liganded and unliganded states. Insights into the role of the 1-6 sequence in the unliganded state were obtained by NMR and related biophysical comparisons of the native and des-1-6 proteins. NMR spectra demonstrated that the environment and/or conformation of residues in the 1-6 sequence differed in liganded and unliganded states. Additionally, the unliganded des-1-6 protein exhibited a dimerization constant four to five times that of the native protein, potentially accounting for the observation that its peptide affinity was also increased. NMR studies further indicated that the increased dimerization constant of the des-1-6 protein correlated with the presence in the native protein of two isoenergetic forms of the monomer, in contrast to only a single form in the des-1-6 protein, as evidenced by signals from an internal dimerization-sensitive alpha-proton. Thus, the 1-6 sequence reduces the dimerization constant by stabilization of an alternative monomer conformation. A second product of Staphylococcus protease V8 digestion of the native protein was identified as the des-1-6 protein with an internal clip after binding site residue Glu-47, the clip presumably breaking the short 3,10 helix that most directly connects the interface to the interface to the binding site. This product, although unable to bind peptide, retained the dimerization constant of the des-1-6 protein, suggesting a lack of importance of the helix in dimerization and contrasting with the effects of the 1-6 sequence. A model is proposed in which the 1-6 sequence stabilizes the second conformation of the unliganded monomer via interactions affecting the loop region that separates the two neurophysin domains and which has been shown to influence neurophysin self-association.
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363
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Zhang J, Zheng C. Extracting evoked potentials with the singularity detection technique. IEEE ENGINEERING IN MEDICINE AND BIOLOGY MAGAZINE : THE QUARTERLY MAGAZINE OF THE ENGINEERING IN MEDICINE & BIOLOGY SOCIETY 1997; 16:155-61. [PMID: 9313095 DOI: 10.1109/51.620509] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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364
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Liu D, Zheng C, Chen Q. [Factors for postoperative persistent hypertension in patients with aldosterone-producing adenoma]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1997; 35:437-9. [PMID: 10677982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
We determined the factors for postoperative persistent hypertension in the patients with aldosterone-producing adrenal adenoma (APA) in 53 patients with APA who were followed up for average 3.1 years. All had normal serum potassium concentration postoperatively. Blood pressure was normal in 37 patients (69.8%) but 18.7/12.7 kPa or more in 16 patients (30.2%) with persistent hypertension. Also compared were sex, age, history of hypertension, effect of reducing blood pressure to antisterone, preoperative blood pressure, time of persistent hypertension, serum potassium concentration, aldosterone concentration in 24 hour urine, amount of PRA, and the type of operation. The results showed that an APA patient aged 50 years or more appears to have a great chance of persistent hypertension than an APA patient under age of 40 years, and the odds ratio is 3:1. There was a significant difference between the mean age for persistent hypertension and for normal blood pressure, and varioas response of reducing blood pressure to antisterone (P < 0.05). It is suggested that for an older APA patient and the patient without of reducing blood pressure to antisterone, there are other factors for hypertension such as renal veinlet change or renal interstitial lesions except for hyperaldosteronism. We recommend renal biopsy (using kidney puncture) at the operating table for those patients in order to understand pathological change and guide treatment after operation.
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365
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Zhang Q, Zhang S, Zheng C. [A new type of reference electrode tube for dynamic monitoring of the acidity in digestive tract]. ZHONGGUO YI LIAO QI XIE ZA ZHI = CHINESE JOURNAL OF MEDICAL INSTRUMENTATION 1997; 21:214-217. [PMID: 11189258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new soft Ag-AgCl electrode tube is introduced in this paper. The character test and clinical application show it is especially suitable for dynamic monitoring of the acidity in upper digestive tract.
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366
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Zheng C, Wang Z. [Control of blood flow in nasal mucosa by electro-stimulation of sphenopalatine ganglion]. ZHONGHUA ER BI YAN HOU KE ZA ZHI 1997; 32:163-6. [PMID: 10743157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The effects of control of blood flow on cat nasal mucosa by stimulating sphenopalatine ganglion (SPG) were studied using laser Doppler flowmetry in order to investigate the role of SPG. The study showed that the stimulation on one side of SPG could induce vasodilation, with increased blood flow, as well as protective reflexes on both sides. The reactivity depended on the stimulation intensity, frequency and duration. The stimulation on one side of postganglionic parasympathetic nerves, in which the stellate ganglion was resected, caused vasodilation only ipsilaterally. The results indicated that the vasodilation induced by stimulating SPG might be mediated via central reflex arc. The "reverse blood regulation" phenomenon was observed during stimulation of SPG as well. The mechanisms of "reverse blood regulation" induced by stimulating SPG need further investigation.
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367
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Yu N, Zheng C, Shi L. Variation in Mitochondrial DNA and Phylogeny of Six Species of Pikas (Ochotona). J Mammal 1997. [DOI: 10.2307/1382892] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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368
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Guo S, Zhang Q, Zheng C. [The development of long-term dynamic multi-parameter monitoring and analyzing system for upper digestive tract]. ZHONGGUO YI LIAO QI XIE ZA ZHI = CHINESE JOURNAL OF MEDICAL INSTRUMENTATION 1997; 21:136-166. [PMID: 11189348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A long-term dynamic multi-parameter monitoring and analyzing system for upper digestive tract is presented. The system can record 24-hour pH values of the esophagus and stomach, and necessary ECG data by pressing event key. Hardware and software is described in the paper.
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369
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Liu J, He T, Zheng C, Huang Y. [Measuring EEG complexity for studying the state of mental load]. SHENG WU YI XUE GONG CHENG XUE ZA ZHI = JOURNAL OF BIOMEDICAL ENGINEERING = SHENGWU YIXUE GONGCHENGXUE ZAZHI 1997; 14:33-7. [PMID: 9817662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The complexity defined by Lemple and Ziv (1976) represents the degree of the sequence randomness. In this paper, the complexity of EEG under different mental loads was measured and the relation between the brain active state and the EEG complexity was analyzed. The results showed a statistically strong relation between the mental load and the EEG complexity. Further study showed that the heavier the mental load was the smaller the EEG complexity became. This correlation was especially apparent in the frontal lobe, and the complexity of EEG might be regarded as one of the parameters representing the functional state of the brain. The results indicate that EEG complexity represents the active state of brain in processing information, and the measurement of EEG complexity may provide a new path to the research in the advanced cognitive function of the human brain.
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370
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Wang C, Zheng C, Ran J. [Materials for joint replacement and friction and wear]. SHENG WU YI XUE GONG CHENG XUE ZA ZHI = JOURNAL OF BIOMEDICAL ENGINEERING = SHENGWU YIXUE GONGCHENGXUE ZAZHI 1997; 14:64-7. [PMID: 9817671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Debilitating diseases such as osteo- and rheumatoid arthritis, trauma and bone cancer can be treated by using prostheses. The wear resistance of materials for joint replacement can affect the service-quality and service-life of prostheses. Materials for joint replacement and friction and wear were briefly reviewed in this paper.
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371
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Fink JM, Hirsch BA, Zheng C, Dietz G, Hatten ME, Ross ME. Astrotactin (ASTN), a gene for glial-guided neuronal migration, maps to human chromosome 1q25.2. Genomics 1997; 40:202-5. [PMID: 9070947 DOI: 10.1006/geno.1996.4538] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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372
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Bølviken B, Flaten TP, Zheng C. Relations between nasopharyngeal carcinoma and magnesium and other alkaline earth elements in soils in China. Med Hypotheses 1997; 48:21-5. [PMID: 9049985 DOI: 10.1016/s0306-9877(97)90019-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Comparison of maps shows a striking geographical relation between high mortality rates from nasopharyngeal cancer in China and low contents of magnesium, calcium and strontium in the soil. We suggest that deficiencies of these elements in the soil could be indirect markers of aetiological factors, e.g. inhalable carcinogens of local natural origin. A search for such factors could be fruitful in further studies of environmental factors in the aetiology of nasopharyngeal carcinoma.
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373
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Cao X, Liu X, Deng Z, Jiang D, Zheng C. [A fast iterative algorithm for adaptive histogram equalization]. ZHONGGUO YI LIAO QI XIE ZA ZHI = CHINESE JOURNAL OF MEDICAL INSTRUMENTATION 1997; 21:8-10. [PMID: 9644133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In this paper, we propose an iterative algorthm called FAHE., which is based on the relativity between the current local histogram and the one before the sliding window moving. Comparing with the basic AHE, the computing time of FAHE is decreased from 5 hours to 4 minutes on a 486dx/33 compatible computer, when using a 65 x 65 sliding window for a 512 x 512 with 8 bits gray-level range.
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374
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Zheng C, Cahill S, Breslow E. The behavior of the active site salt bridge of bovine neurophysins as monitored by 15N NMR spectroscopy and chemical substitution. Relationship to biochemical properties. Biochemistry 1996; 35:11763-72. [PMID: 8794757 DOI: 10.1021/bi960906a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The active site of liganded neurophysin contains a salt bridge that involves the side chains of Arg-8 and Glu-47 of the protein and the alpha-amino group of bound hormone or related peptide. The extent to which the Arg-8-Glu-47 salt bridge persists in the absence of peptide, or to which the environment of Arg-8 in the unliganded state differs in monomers and dimers, is relevant to an understanding of allosteric mechanism in this system. In the present study, the behavior of the salt bridge was investigated by 15N NMR and chemical replacement of Arg-8. Bovine neurophysin-I was converted to its des 1-8 derivative, and Arg-8 was replaced by 15N-substituted Arg or by other residues using chemical semisynthesis. The relative abilities of different amino acids to restore peptide affinity to the des 1-8 protein were in good accord with the view of the salt bridge in the liganded state obtained from crystals of bovine neurophysin-II complexes. In the unliganded state, comparison of the 15N and proton NMR signals from Arg-8 with those in smaller arginine systems suggested the absence of significant interactions between the guanidinium of Arg-8 and Glu-47 or between the amino terminal region of Arg-8 and other elements of the protein. No evidence of a difference in Arg-8 environment between unliganded monomers and dimers was found. Marked spectral changes accompanying the binding of oxytocin indicated changes in the environment of both the side chain and amino terminal region of Arg-8. The NMR results were in good agreement with a recently emerging comparison of bovine neurophysin-II derivatives in the liganded and unliganded states, with the notable exception of the extent of salt bridge formation in the unliganded state. The results are shown to be consistent with, and to help explain, significant differences between the two bovine neurophysins in the susceptibility to tryptic cleavage at Arg-8 in the unliganded state and in the pH dependence of peptide binding and additionally constrain potential allosteric mechanisms underlying neurophysin ligand-facilitated dimerization.
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375
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Jiang X, Shen L, Zheng C, Zeng Q, Fan W. [Combustion under microgravity and technique of fire prevention and suppression in space cabin]. HANG TIAN YI XUE YU YI XUE GONG CHENG = SPACE MEDICINE & MEDICAL ENGINEERING 1996; 9:302-7. [PMID: 11539917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
This is a brief review on microgravity combustion, along with the discussion of the fundamental characteristics of combustion and fire processes under microgravity. Recent research activities in microgravity combustion and space fire prevention were emphasized. In addition, the potential use of flame-inhibiting atmospheres in the space cabin was introduced. The technique of fire detection and extinguishment in spacecraft environments was also discussed.
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