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Biomedical subjects

Yurong Wang

Publications and source records attributed to Yurong Wang.

7 recordsLinked to original sources
PubMed2006

Fabrication of a gold microelectrode for amperometric detection on a polycarbonate electrophoresis chip by photodirected electroless plating.

A novel method of photoresist-free micropatterning coupled with electroless gold plating is described for the fabrication of an integrated gold electrode for electrochemical detection (ED) on a polycarbonate (PC) electrophoresis microchip. The microelectrode layout was photochemically patterned onto the surface of a PC plate by selective exposure of the surface coated without photoresist to 254 nm UV light through a chromium/quartz photomask. Thus, the PC plate was selectively sensitized by formation of reactive chemical moieties in the exposed areas. After a series of wet chemistry reactions, the UV-exposed area was activated with a layer of gold nanoparticles that served as a seed to catalyze the electroless plating. The gold microelectrode was then selectively plated onto the activated area by using an electroless gold plating bath. Nonselective gold deposition on the unwanted areas was eliminated by sonication of the activated PC plate in a KSCN solution before electroless plating, and the adhesion of the plated electrodes to the PC surface was strengthened with thermal annealing. Compared with the previously reported electroless plating technique for fabrication of microelectrodes on a microchip, the present method avoided the use of a membrane stencil with an electrode pattern to restrict the area to be wet-chemically sensitized. The CE with integrated ED (CE-ED) microchip was assembled by thermal bonding an electrode-plated PC cover plate to a microchannel-embossed PC substrate. The novel method allows one to fabricate low-cost, electrode-integrated, complete PC CE-ED chips with no need of a clean room. The fabricated CE-ED microchip was demonstrated for separation and detection of model analytes, including dopamine (DA) and catechol (CA). Detection limits of 0.65 and 1.03 microM were achieved for DA and CA, respectively, and theoretical plate number of 1.4 x 10(4) was obtained for DA. The plated gold electrode can be used for about 4 h, bearing usually more than 100 runs before complete failure.

Catechols↗
PubMed2005

Integrated capillary electrophoresis amperometric detection microchip with replaceable microdisk working electrode. II. Influence of channel cross-sectional area on the separation and detection of dopamine and catechol.

The interference of separation high voltage with the electrochemical detection is a major challenge to the microchip capillary electrophoresis-electrochemical detection systems with end-channel detection mode. Using dopamine and catechol as model analytes, the influences of channel cross-sectional area and channel-to-electrode distance on the high-voltage interference, accordingly on the separation and detection performances of the microchip capillary electrophoresis-electrochemical detection system were investigated. With the increase of the channel cross-sectional area from 312 through 450-615 microm2, the apparent half-wave potentials of hydrodynamic voltammetry for dopamine at the field strength of 288 V/cm shifted positively from 285 through 330-400 mV. By using a chip with the smallest channel cross-section (312 microm2 with top width of 37.3 microm and depth of 8.9 microm) the residual high-voltage field in the detection cell was small, so that detection was conducted at a channel-to-electrode distance of 20 microm to achieve better performances of separation and detection.

Catechols↗
PubMed2004

[The immediate local skin flaps transference for the treatment of acute auricle trauma defect].

OBJECTIVE: To investigate the advantage and postoperation notice of immediate local skin flaps transference for the treatment of acute auricle trauma defect. METHOD: A retrospective study was carried out to judge the immediate local skin flaps transference for sixty-three patients who underwent ear injury. RESULT: All the flaps survived postoperation. After a follow-up observation for 12-18 months, the shapes of all patients' ears were satisfying, and there were no osteochondritis. CONCLUSION: Immediate local skin flaps transference for the treatment of acute auricle trauma defect could recover the shape of ears in short time. The colour of flaps were similar as the ears, so the local skin flaps were ideal material for the ear reconstruction. If the wound were contaminated, antibiotics must be used, in addition to the Dexamethasone intravenous for seven to ten days which may inhibit the osteochondrites to some extent.

Adolescent↗
PubMed2003

Phase-shifting with computer-generated holograms written on a spatial light modulator.

We propose a new computer-controlled phase-shifting method based on computer-generated holograms (CGHs) displayed on a spatial light modulator (SLM). In this method the accurate phase shifts required in phase-shifting digital holography or interferometry are induced by a suitable transformation of the encoding patterns of the CGH displayed on a SLM. Both the theoretical analysis and the experimental results demonstrate the feasibility of this approach. We also discuss possible applications of this method in the field of interferometric null testing of aspheres.

Journal Article↗
PubMed2003

Reduced gap junctional intercellular communication and altered biological effects in mouse osteoblast and rat liver oval cell lines transfected with dominant-negative connexin 43.

Gap junctional intercellular communication (GJIC) maintains normal growth and differentiation of cells in a tissue. The intercellular molecules traversing gap junctions are largely unknown, but the molecular weight (MW) cutoff is normally 1200 Da. No differences in dye transfer were observed in normal or vector controls of WB-F344 rat liver epithelial or mouse osteoblastic MC3T3-E1 cells with either Lucifer Yellow (LY) with a MW of 457 Da (LY-457) or LY with a MW of 649 Da (LY-649). Transfection of a dominant negative-connexin 43 (Cx43) gene decreased GJIC (>50%) when LY-649 was used, however, normal GJIC was observed in both cell lines when LY-457 was used. Therefore, the MW cut off in these clones was considerably less than the wild type. The dominant negative clones of the MC3T3-E1 cells exhibited over 90% less alkaline phosphatase (ALPase) activity and calcium deposition after the induction of differentiation. Similarly, dominant negative Cx43 inhibited gene expression of ALPase and bone sialoprotein but not osteocalcin in MC3T3-E1. WB-F344 cells normally exhibit a biphasic response to 12-O-tetradecanoylphorbol-13-acetate (TPA) where inhibition of GJIC recovers after 2 h, but the dominant negative clones showed no recovery from inhibition of GJIC by TPA. Dominant negative Cx43 also inhibited the formation of network-like structures by WB-F344 cells on Matrigel. These results demonstrate that the dominant negative gene transfected into cell types containing the wild-type connexins result in diminished channel sizes, thus allowing the determination of whether distinct biological endpoints, i.e., differentiation, are dependent upon either small or high MW intercellular signals.

Animals↗
PubMed2003

Localized aggressive periodontitis in primary dentition: a case report.

BACKGROUND: A 5-year-old Japanese boy presented with persistent gingival inflammation and severe mobility of the right lower primary incisors. Due to severe alveolar bone loss and a deep periodontal pocket (5 mm), the incisors were extracted at the second visit. METHODS: Clinical, radiographic, histological, and microbiological examinations were carried out. Then, the polymerase chain reaction (PCR) technique was employed to detect specific periodontal pathogens. The chemotactic activity of polymorphonuclear neutrophils was also measured. RESULTS: Tannerella, Capnocytophaga, Fusobacterium, and Eikenella sp. were recovered from the subgingival microflora around the right lower incisors, while A. actinomycetemcomitans, Tannerella forsythensis (formerly Bacteroides forsythus), Prevotella nigrescens, Campylobacter rectus, and Capnocytophaga gingivalis were detected using the PCR method. Further chemotaxis assay revealed that neutrophil function was depressed compared with that of healthy controls. CONCLUSIONS: Although inflammation remained around the right primary second molars, the bone loss was controlled by periodic professional mechanical teeth cleaning (PMTC), subgingival irrigation, and local antibiotic application. The probing depths of all teeth, including permanent incisors and molars, were within 2.5 mm.

Alveolar Bone Loss↗