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Biomedical subjects

Yu Fu

Publications and source records attributed to Yu Fu.

At least 55 records · Page 3Linked to original sources
PubMed2004

Instantaneous velocity displacement and contour measurement by use of shadow moiré and temporal wavelet analysis.

A temporal wavelet analysis method is proposed for velocity, displacement, and three-dimensional surface-profile measurement of a continuously deforming object by use of the shadow moiré technique. A grating is placed close to a deforming object, and its shadow is observed through the grating. The moiré fringe patterns, generated by the interference of the grating lines and their shadows, are captured by a high-speed CCD camera with a telecentric gauging lens. Instantaneous frequency of gray-value variation is evaluated point by point with the continuous wavelet transform. From the instantaneous frequency of each point on the object, the velocity, displacement, and high-quality surface profile at different instants can be retrieved. In this application, two specimens are tested to demonstrate the validity of the proposed method: One is a small coin with a rigid body motion, and the other is a simply supported beam subjected to a central point load. The results are compared with those obtained from temporal Fourier-transform and mechanical stylus methods.

Journal Article↗
PubMed2004

Rhodium-catalyzed asymmetric hydrogenation of functionalized olefins using monodentate spiro phosphoramidite ligands.

Novel chiral monodentate phosphorus ligands, SIPHOS, were conveniently synthesized from 1,1'-spirobiindane-7,7'-diol. The Rh complexes of SIPHOS can catalyze the hydrogenation of alpha-dehydroamino esters in mild conditions, providing alpha-amino acid derivatives in up to 99% ee. Enamides and beta-dehydroamino esters can also be hydrogenated in good to excellent enantioselectivities (up to 99% and 94% ee, respectively). The SIPHOS ligand with smaller alkyl groups on the N-atom afforded higher enantioselectivity. The X-ray analysis of single crystal showed that the structure of Rh/SIPHOS catalyst is [Rh(COD)((S)-SIPHOS-Me)(2)](+), which clarified the configuration of the catalyst with the monodentate chiral phosphorus ligand in Rh-catalyzed asymmetric hydrogenation. A positive nonlinear effect in the relationship of the optical purities of ligand and product was observed in the hydrogenation of dehydroamino acid derivatives. The kinetic study of hydrogenation showed that the reaction is zero order in the concentration of substrate and first order in the concentration of Rh catalyst and the hydrogenation pressure. The rate of hydrogenation decreased when the Rh/L ratio changed from 1:1 to 1:4.

Journal Article↗
PubMed2004

The TRAF6 RING finger domain mediates physical interaction with Ubc13.

Tumor necrosis factor receptor associated factor 6 (TRAF6) is an important signaling molecule involved in a diverse array of physiological processes. It has been proposed that TRAF6, a RING finger-containing protein, acts as a ubiquitin ligase (E3) and a target for Lys-63 linked polyubiquitination mediated by Ubc13-Uev, a ubiquitin conjugating (E2) complex. However, the physical interaction between TRAF6 and this E2 complex has not been reported. We used the yeast two-hybrid assay to demonstrate that TRAF6 indeed interacts with the E2 complex through its direct binding to Ubc13. Either a single Cys-to-Ser substitution within the TRAF6 RING finger domain or an amino acid substitution on the Ubc13 surface, that is predicted to interact with RING finger proteins, is able to abolish the interaction. In addition, we found that TRAF6 can interact with itself and this self-interaction domain is mapped to the N-terminus containing the RING finger motif. Based on this study and our previous Ubc13-Uev structural analysis, the interface of Ubc13-TRAF6 RING finger can be predicted.

Amino Acid Motifs↗
PubMed2004

Polyelectrolyte multilayer as matrix for electrochemical deposition of gold clusters: toward super-hydrophobic surface.

This communication describes the use of polyelectrolyte multilayer as a preformed matrix in electrochemical deposition to adjust the morphology of gold clusters, and only the surface covered with dendritic gold clusters shows a super-hydrophobic property, with the contact angle above 150 degrees and the tilt angle less than 1.5 degrees , after the surface further chemisorbed with a self-assembled monolayer of n-dodecanethiol.

Journal Article↗
PubMed2004

[A study on the correlation between HLA-DR genes and susceptibility to pulmonary tuberculosis in a population of Han nationality from southern China].

OBJECTIVE: To analyze the association between HLA-DR genes and pulmonary tuberculosis and to explore susceptible genes associated with pulmonary tuberculosis in a population of Han nationality from southern China. METHODS: Using case-control study, we detected by polymerase chain reaction-sequence specific primers (PCR-SSP) technique the 23 alleles of HLA-DR gene sites in 110 tuberculosis cases and 101 controls from Guangdong, Guangxi, Hunan, Hubei, Jiangxi and Fujian provinces. Gene frequency (GF) and odds ratio (OR) were calculated and compared. RESULTS: The frequency of DR16 allele in pulmonary tuberculosis cases was strikingly higher than that in the healthy controls (chi2=5.915, Pc< 0.05). Their GFs were 12.62% and 5.60% respectively, and the OR was 2.53. Significantly decreased frequency of DR1 and DR13.3 alleles in cases were found (chi2 values were 17.847 and 14.258 respectively, Pc < 0.01). Their ratios of GFs were 8.08% vs. 23.57% and 29.29% vs. 50.24%, and their ORs were 0.26 and 0.33 respectively. CONCLUSIONS: The results suggest that DR16 allele is closely correlated to incidence of pulmonary tuberculosis in this population of Han nationality from southern China, or linked to susceptible genes which are functional. It is also suggested that expression of DR1 and DR13.3 alleles may be associated with an antagonist effect in the pathogenesis of pulmonary tuberculosis in this population.

Adolescent↗
PubMed2004

Biphasic firing response of nucleus accumbens neurons elicited by THPB-18 and its correlation with DA receptor subtypes.

AIM: To investigate the possibility whether THPB-18 (l-12-shloroscoulerine) possesses the D1 agonist-D2 antagonist action on meso-accumbens-mPFC DA system. METHODS: Single unit spontaneous firing activity was recorded in the nucleus accumbens (NAc) neurons of naive and unilateral-6-hydroxydopamine (6-OHDA)-lesioned Sprague-Dawley rats. The effects of drugs applied intravenously or iontophoretically were determined by the change of firing rates. RESULTS: Under normal conditions, the systemic administration of THPB-18 produced a decrease-increase biphasic firing pattern in the NAc neurons during cumulative doses. High dose of THPB-18 was capable of reversing the inhibition induced by both D2 agonist LY171555 and D1/D2 agonist APO on NAc firing activity. Spiperone pretreatment could not block the high dose of THPB-18-induced firing rate increase, which was reversed by the D1 selective antagonist SCH23390. The tested NAc neurons were effectively inhibited by iontophoretically applied THPB-18 in 90 % of 6-OHDA-lesioned rats, while THPB-18 caused variable effects on the firing of NAc neurons in the neurons of unlesioned rats. The inhibitory effect of THPB-18 was blocked by iontophoretic application of SCH23390, but not D2 antagonist spiperone. CONCLUSION: Similar to L-stepholidine, THPB-18 also possesses the D1 agonistic-D2 antagonistic dual action on the VTA-NAc DA system.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed2004

[Experimental study on xiaoliu decoction in treating tumor and modulating immune function].

OBJECTIVE: To study the anti-tumor effect and immune function modulation of Xiaoliu decoction (XLD) and to explore the possible mechanism. METHODS: S180 tumor bearing mice were treated with large or small dose of XLD and cyclophosphamide (CTX) to observe the tumor suppressive rate, lymphocyte transformation rate, natural killer cell (NK) activity, tumor necrosis factor alpha (TNFalpha) level in the mice, as well as the tumor cell apoptosis in vitro. RESULTS: The tumor suppressive rate of XLD on tumor bearing mice was over 30%. XLD showed obvious trend in enhancing the tumor suppressing rate of chemotherapy, could increase the lymphocyte transformation rate, NK activity, and TNFalpha level. It also could accelerate the tumor cell apoptosis in vitro. CONCLUSION: XLD has significant anti-tumor effect, it could elevate the immune function or organism and alleviate the chemotherapy induced lowering of immune function.

Adjuvants, Immunologic↗
PubMed2003

Spatial-fringe-modulation-based quality map for phase unwrapping.

The quality-guided algorithm is a method widely used in phase unwrapping. The algorithm uses a quality map to guide its unwrapping process, and its validity depends on whether the quality map can truly reflect phase quality. In fringe projection surface profilometry, discontinuous surface structure, low surface reflectivity, and saturation of the image-recording system are sources of unreliable phase data. To facilitate the unwrapping process, we demonstrate an accurate quality map based on spatial fringe modulation, which is extracted from a single fringe pattern. Compared with temporal fringe modulation, the new criterion is more sensitive to spatial structure changes and less dependent on illumination conditions.

Journal Article↗
PubMed2003

Functional domains required for the Saccharomyces cerevisiae Mus81-Mms4 endonuclease complex formation and nuclear localization.

The Saccharomyces cerevisiae Mms4 and Mus81 proteins form a specific complex, which functions as an endonuclease specific for branched DNA molecules and protects cells from killing by DNA alkylation damage, but not damage induced by ionizing radiations. In an effort to further understand the structure and functions of the Mus81-Mms4 complex, we attempted to define domains required for complex formation and nuclear localization through deletion and mutagenesis analyses. Combined yeast two-hybrid and co-immunoprecipitation experiments indicate that the C-terminal 100 amino acids of both Mus81 and Mms4 are required and sufficient for heterodimer formation. However, a single amino acid substitution in Mms4 in the N-terminal region is able to abolish the interaction, which suggests that the three-dimensional structure is also important for Mms4 to interact with Mus81. By fusion to green fluorescent protein and in vivo subcellular localization studies, we demonstrate that Mms4 and Mus81 are nuclear proteins and can be localized to the nucleus independently. Deletion analyses indicate that one of two putative nuclear localization signals (residues 244-263) in Mms4 is required for localization, whereas the N-terminal half of Mus81 is necessary and sufficient for its localization to the nucleus.

Cell Nucleus↗
PubMed2003

[Molecular epidemical characteristics of Mycobacterium tuberculosis strains from the nationwide random survey for the epidemiology of tuberculosis in China, 2000].

OBJECTIVE: To explore the epidemical distribution characteristics of Mycobacterium tuberculosis isolated from China. METHODS: The M. tuberculosis strains were gained by multi-stratified grouping random sampling method from the nationwide random survey for the epidemiology of tuberculosis in China, 2000, and analyzed by IS6110-based RFLP and DR-based Spoligotyping DNA fingerprinting. These fingerprinting patterns were transferred into digital data and compared each other, and clustered by Gel compar4.1 Software. The clustering values in different TB patients were compared by chi(2) test and the risk factors for recent transmission were calculated by Odd Ratios. RESULTS: Two hundreds and four of 402 M. tuberculosis strains from this survey were determined to be "Beijing Genotype" M. Tuberculosis strain by DNA fingerprinting analysis. Three clusters M. tuberculosis strains sharing identical fingerprint pattern were found, including one cluster belong to a same family. There were significant difference between female and male, and younger (< 40 years old) and elder (>or= 40 years old) (P < 0.05). Odds Ratio 1 showed youth [1.68 95% CI (1.01 - 2.80)] and male [2.04 95% CI (1.07 - 3.96)], but Odds Ratio 2 showed youth [0.3 95% CI (0.2 - 0.44)] and male [4.96 95% CI (2.77 - 9.00)]. CONCLUSION: M. tuberculosis strains of Beijing Genotype are prevailing in China at present. Male and elder were shown to be significant risk factors for recent transmission. The infection source of M. tuberculosis could be traced by DNA fingerprinting.

Adult↗
PubMed2003

[Study of delaying hospital admission after acute stroke].

OBJECTIVE: To explore the association between hospital admission after acute stroke and delaying factors, and try to determine the factors that delay hospital admission and treatment, in order to find good solution. METHODS: We studied 300 patients with acute stroke from Sep. 2002 to Mar. 2003 in our emergency department and used chi 2 test and logistic model to analyze the collected data. RESULTS: The stroke subtypes were confirmed by CT or MRI scan in all the patients, including 210 cases of cerebral infarction, 80 cases of cerebral hemorrhage, and 10 cases of subarachnoid hemorrhage. The most important factor associated with a delay in reaching the hospital was the pattern of arriving hospital. Other factors associated with a delay were the referred hospital, stroke subtype and distance from the hospital. CONCLUSION: The majority of patients who are candidates for acute stroke arrive at the hospital after prolonged delays for multiple reasons. The main reason for hospital admission delay is that they do not pay enough attention. Public and medical personnel education could result in significant reduction of these delays.

Adult↗
PubMed2003

Puerarin blocks Na+ current in rat ventricular myocytes.

AIM: To study the effect of puerarin (Pue) on Na+ channel in rat ventricular myocytes. METHODS: Whole-cell patch-clamp technique was applied on isolated cardiomyocytes from rats. RESULTS: Pue inhibited cardiac INa in a positive rate-dependent and dose-dependent manner, with an IC(50) of 349 micromol/L. The kinetics of blockage of cardiac sodium channel by Pue resembled the ClassIa/Ic of antiarrhythmic agents. Pue 300 micromol/L did not alter the shape of the I-V curve of INa, but markedly shifted the steady-state inactivation curve of INa towards more negative potential by 15.9 mV, and postponed the recovery of INa inactivation state from (21.9+/-1.6) ms to (54.4+/-3.4) ms (P<0.01). It demonstrated that the steady state of inactivation was affected by Pue significantly. CONCLUSION: Pue protected ventricular myocytes against cardiac damage and arrhythmias by inhibiting recovery from inactivation of cardiac Na+ channels.

Animals↗