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Biomedical subjects

Y J Huang

Publications and source records attributed to Y J Huang.

At least 19 recordsLinked to original sources
PubMed2006

Three-dimensional conformal radiotherapy for the treatment of arteriovenous shunting in patients with hepatocellular carcinoma.

The objective of this study is to evaluate the efficacy of radiotherapy for the treatment of arteriovenous shunting (AVS) in patients with hepatocellular carcinoma (HCC). Between November 1997 and April 2005, 20 HCC patients with AVS were referred to our department for radiotherapy. The radiation was delivered with 10-15 MV X-ray given 5 days per week at 2 approximately 2.5 Gy per fraction. Total doses ranged from 45 to 64 Gy (median dose 60 Gy). The patients were followed up with color Doppler sonography. When non-invasive imaging suggested obliteration, X-ray angiography was performed to verify the results. Four of the 20 AVS proved to be completely obliterated at X-ray angiography in 1.9, 2.8, 1.8 and 2.9 months after radiotherapy. One of the remaining 16 showed obvious regression on Doppler sonography 0.5 months after radiotherapy, but X-ray angiography was not performed to verify the result. Radiation-related hepatic failure did not occur during the follow-up period. In conclusion, radiotherapy is a treatment alternative for AVS in HCC patients and gives patients with poor prognosis the chance to receive further transcatheter arterial embolization.

Adult↗
PubMed2006

The relationship between polymorphisms of HCMV UL144 ORF and clinical manifestations in 73 strains with congenital and/or perinatal HCMV infection.

Human cytomegalovirus (HCMV) displays genetic variability and can cause a wide range of diseases in neonates. To explore the relationship between polymorphisms and clinical manifestations, the UL144 genes from 73 clinical strains were sequenced. All of the strains, which came from 70 infants with suspected congenital and/or perinatal HCMV infection, were non-passage strains. Among them, 23 strains were from surgery specimens, and the others were from urine samples. Clinically, 12 infants displayed asymptomatic infection and 58 patients displayed symptomatic infection. The results showed that 36 patients (49.3%) were infected with strains belonging to UL144 group G1 (G1a 33/36, G1b 3/36), 19 patients (28.8%) were infected with strains belonging to group G2, and 15 patients (21.9%) were infected with strains belonging to group G3. This result indicated that UL144 group G1 was the predominant genotype in congenital and/or perinatal HCMV infection in northern China. Compared with the distribution pattern of strains in UL144 genotypes of data from Chicago, Iowa and Texas, and Japan by chi-square test, the difference was statistically significant. This suggested that the distribution pattern of strains in UL144 genotype was related to geographic location. However, no linkage was observed between the UL144 genotypes and the severity and/or outcome of HCMV disease.

Base Sequence↗
PubMed2006

Pyrolysis and oxidation kinetics of medical wastes.

On account of the infectious properties of medical wastes, most are treated carefully by incineration to ensure proper destruction of pathogens. However, the behaviors of medical wastes are not well understood during the process of incineration. Thus, the aim of this work is to investigate pyrolysis and oxidation kinetics of the medical wastes, including cottons, gauzes, saline bottles, stomach medicines with the thermal gravimetric analysis (TGA) method. Experimentally, the degradation of cottons and saline bottles in pyrolysis and oxidation occurred at about 530 K and 510 K as well as 630 K and 530 K, respectively. Oxygen affects the degradation reaction of cottons and saline bottles at lower temperatures. The rate equations of the first stage of thermal treatment in different oxygen contents also showed that oxygen would decrease the activation energies of decomposition of cottons, gauzes and saline bottles. But the presence of oxygen did not influence the decomposition of stomach medicines at temperatures below 550 K, while only pyrolysis took place.

Hot Temperature↗
PubMed2005

Using biosensors to detect the release of serotonin from taste buds during taste stimulation.

CHO cells transfected with high-affinity 5HT receptors were used to detect and identify the release of serotonin from taste buds. Taste cells release 5HT when depolarized or when stimulated with bitter, sweet, or sour tastants. Sour- and depolarization-evoked release of 5HT from taste buds is triggered by Ca2+ influx from the extracellular fluid. In contrast, bitter- and sweet-evoked release of 5HT is triggered by Ca2+ derived from intracellular stores.

Adenosine Triphosphate↗
PubMed2003

Decomposition of NO on the alkalized Pt/Al2O3.

Catalytic decomposition of NO on platinum catalysts at 873-1,173 K was investigated in the present work. The yield of N2 in the NO decomposition process was significantly increased on the alkalizing Pt/Al2O3 catalyst. The enhancement may be attributed to a trap of additional NO molecules by basic sites ofthe alkalized catalyst. The interstitially adsorbed species (NaOH(NO)Pt) might increase the NO adsorption strength during the catalytic NO reduction process. Pt on the high acidity HY was also active for catalytic decomposition of NO. Nevertheless, its activity decreased at higher temperatures (>1,073 K) because of the distortion of the HY framework. Combined results of XPS (X-ray photoelectron spectra) and TPR (temperature programmed reduction) showed that PtO and PtO2 were the main active species on the alkalized Al2O3 and HY during NO reduction.

Adsorption↗
PubMed2003

The feasibility study of the octane-enhancing process: isobutylene dimerization using C4 mixture.

The dimerization of isobutylene to diisobutylene in C4 mixture was evaluated using various catalysts such as nickel salts system, zeolite system and acidic ion exchange resin. There were shown that the strong acidic type ion exchange resin (Amberlyst 15) under 6 kg/cm2 and 60 degrees C gave rise to 90% conversion and more than 60% selectivity to diisobutylene with acceptable amounts of oligomer as a best catalyst. Therefore, Amberlyst 15 was employed to investigate the optimum reaction condition. In the batch reaction, since the catalyst activity was increased with the increasing reaction temperature, the reaction time should be shortened appropriately to prevent a high yield of oligomer. The reaction rate was increased by the increased amount of catalyst without much change in the product composition. The formation of oligomer was inhibited when a small amount of organic solvents (methyl tert-butyl ether) are attended. In the fixed-bed study, the results indicate that the increase in reaction temperature was accompanied by the increase in reaction rate, however, the selectivity to the dimer was affected. Higher WHSV will enhance the selectivity but reduce the conversion. Conclusively, the appropriate reaction condition was 45 degrees C with WHSV of 10.

Air Pollution↗
PubMed2001

Solution NMR structure and folding dynamics of the N terminus of a rat non-muscle alpha-tropomyosin in an engineered chimeric protein.

Tropomyosin is an alpha-helical coiled-coil protein that aligns head-to-tail along the length of the actin filament and regulates its function. The solution structure of the functionally important N terminus of a short 247-residue non-muscle tropomyosin was determined in an engineered chimeric protein, GlyTM1bZip, consisting of the first 19 residues of rat short alpha-tropomyosin and the last 18 residues of the GCN4 leucine zipper. A gene encoding GlyTM1bZip was synthesized, cloned and expressed in Escherichia coli. Triple resonance NMR spectra were analyzed with the program AutoAssign to assign its backbone resonances. Multidimensional nuclear Overhauser effect spectra, X-filtered spectra and (3)J(H(N)-H(alpha)) scalar coupling were analyzed using AutoStructure. This is the first application of this new program to determine the three-dimensional structure of a symmetric homodimer and a structure not previously reported. Residues 7-35 in GlyTM1bZip form a coiled coil, but neither end is helical. Heteronuclear (15)N-(1)H nuclear Overhauser effect data showed that the non-helical N-terminal residues are flexible. The (13)C' chemical shifts of the coiled-coil backbone carbonyl groups in GlyTM1bZip showed a previously unreported periodicity, where resonances arising from residues at the coiled-coil interface in a and d positions of the heptad repeat were displaced relatively upfield and those arising from residues in c positions were displaced relatively downfield. Heteronuclear single quantum coherence spectra, collected as a function of temperature, showed that cross-peaks arising from the alpha-helical backbone and side-chains at the coiled-coil interface broadened or shifted with T(M) values approximately 20 degrees C lower than the loss of alpha-helix measured by circular dichroism, suggesting the presence of a folding intermediate. The side-chain of Ile14, a residue essential for binding interactions, exhibited multiple conformations. The conformational flexibility of the N termini of short tropomyosins may be important for their binding specificity.

Amino Acid Sequence↗
PubMed2001

EXAFS study of copper in waste incineration fly ashes.

Copper species such as CuCO3, Cu(OH)2, CuS and CuO were found in the bag house and EP (electrostatic precipitator) fly ashes of waste incineration processes by X-ray absorption near edge structural (XANES) spectroscopy. A small amount of Cu(I) and metallic Cu was found in the bag house fly ash. The averaged Cu-O bond distance in the fly ashes determined by EXAFS (extended X-ray absorption fine structural) was 1.96 A with coordination numbers of 2.4-3.9. However, the Cu-(O)-Cu (2nd shell) bond distance of the fly ashes in the incineration process was decreased by 0.19-0.21 A if compared to that of the CuO standard. The coordination numbers of the 2nd shell contribution to the bag house fly ash were not very significant.

Carbon↗
PubMed2001

TUNEL staining and electron microscopy studies of apoptotic changes in the guinea pig vallate taste cells after unilateral glossopharyngeal denervation.

On the basis of our previous report that unilateral glossopharyngeal neurectomy in the guinea pig resulted in degeneration and disappearance of taste buds in ipsilateral vallate papillae (Huang and Lu 1996), it is reasonable to speculate that gustatory denervation may enhance apoptosis of taste bud cells, with taste buds decreasing in number and ultimately disappearing after neurectomy. We were therefore determined to investigate apoptosis of taste bud cells in guinea pig vallate papillae after unilateral glossopharyngeal neurectomy using both terminal deoxynuleotidyl transferase (TdT)-mediated dUTP nick-end labelling (TUNEL) at the light microscopic level and by conventional electron microscopy. A total of 34 adult guinea pigs were unilaterally glossopharyngeal-neurectomized and sacrificed at 3, 6, 12 h and 1, 3 and 7 days after surgery. The results revealed that only a very few TUNEL-positive nuclei indicating apoptosis were present in normal taste buds, but in surgically denervated papillae, they increased in number from 6 h-12 h after surgery, reached at peak on day 1 and then gradually decreased. In apoptotic cells from normal taste buds, electron microscopy revealed condensation of the chromatin against the nuclear envelope, changes in the nuclear envelope, and fragmentation of the nucleus, but the integrity of the plasma membrane and organelles was maintained. Neurectomized taste cells were also characterized by condensed and fragmentary nuclei, compactness of the cytoplasmic organelles, and the appearance of pedunculated protuberances on the cell surface. From these observations, we conclude that: (1) glossopharyngeal neurectomy enhanced apoptosis of vallate taste bud cells in guinea pig; (2) appropriate gustatory nerve innervation is an essential component for the maintenance of the taste bud, and may play a role in apoptosis of taste cells.

Animals↗
PubMed2001

Output-sliding control for a class of nonlinear systems.

In this paper, a systematic output-sliding control design methodology for nonlinear multivariable systems is presented. The control law consists of a continuous nominal control and a discontinuous switching control. The former is the equivalent control for the system with all uncertainties at zero and the latter is designed for nonzero uncertainties. Simulation results indicate that the proposed switching control law drives the system state trajectories onto the chosen switching surface in finite time and the output tracking is achieved.

Journal Article↗
PubMed2001

Robust control for a class of time varying systems via switching hypersurface design with output signals.

Sliding mode control methods have been used widely since they provide robustness against parameter variations and disturbances. This paper focuses on the problem of a robust output-sliding control design for linear uncertain multi-input multi-output time-varying systems with norm-bounded uncertainty. Output signals are used for the definition of switching hypersurfaces. The formulation of a control law is emphasized. Output tracking can be achieved against a class of time varying parameter variations and external disturbances. The effectiveness of the proposed output-sliding control is confirmed by an application example.

Journal Article↗
PubMed2001

Placing all closed loop poles of missile attitude control systems in the sliding mode via the root locus technique.

This paper presents a robust control method for uncertain nonminimum phase systems with external disturbances. A systematic design algorithm is developed which links the sliding mode control and the root locus technique. Complete closed-loop pole placement is achieved in addition to the placement of the reduced order equivalent system poles. An integration function is employed in the sliding variable formulation. The output tracking error is guaranteed to vanish. The proposed method was successfully applied to control the angle of attack of a missile attitude control system.

Journal Article↗
PubMed2001

Effect of interleukin (IL)-12 and IL-15 on apoptosis and proliferation of umbilical cord blood mononuclear cells.

Decreased graft-versus-host disease (GVHD) in cord blood (CB) transplantation may be attributed to the immunological immaturity and susceptibility to apoptosis of CB mononuclear cells (MNCs). Cytokines like interleukin (IL)-12 and IL-15 may be used for in vivoadministration or ex vivo expansion of lymphoid cells for more rapid recovery following stem cell transplant, and for providing a graft-versus-leukemia (GVL) effect. We investigated the effects of IL-12 and IL-15, alone or in combination on apoptosis and proliferation of both CB and adult peripheral blood (APB) MNCs, with particular emphasis on CB CD4+, CD8+ and CD56+ lymphocyte subpopulations. The results of our study indicated that: (1) the combination of IL-12+IL-15 resulted in a greater degree of CB and APB apoptosis than either cytokine alone; (2) the level of both spontaneous and cytokine-induced apoptosis by IL-12 and/or IL-15 are greater in CB MNCs than in APB MNCs using TUNEL assays; (3) IL-15 is superior to IL-12 in enhancing the proliferative response in CB and APB MNCs; (4) the combination of IL-12+IL-15, but not either cytokine alone, significantly enhanced apoptosis in CD8+ and CD56+ CB subsets, but not in CD4+ CB subsets; (5) IL-12 or IL-15 alone resulted in increased proliferation in CD4+, CD8+ and CD56+ CB subsets, with IL-12+IL-15 producing the greatest increase of proliferation in all three CB subsets; and (6) IL-15 and/or IL-12 significantly upregulate Fas (CD95) expression on CB T and NK cells. These findings may have therapeutic implications when designing cytokine therapy in patients receiving CB transplant.

Adult↗
PubMed2000

[Evaluation of two-dimensional and color Doppler ultrasonography in diagnosis of peritoneal mesothelioma].

OBJECTIVE: To evaluate diagnostic value of two-dimensional and color Doppler ultrasonography in peritoneal mesothelioma. METHODS: Ten cases of ultrasonograms and color Doppler ultrasonographic manifestations in 3 cases of them were analysed and compared with the outcome of surgery and pathology. RESULTS: Images of 8 cases were showed to be hypoechoic mass which some had no-echoic area; 5 to be ascites; 5 to be peritoneal thickness. With color Doppler, we saw the mass which is rich in the blood flow. CONCLUSION: Combining clinical manifestations, ultrasonography is of benefit to initial diagnosis of peritoneal mesothelioma.

Adult↗
PubMed2000

Minimization of cobalt nuclide emissions in supercritical water oxidation of spent resin.

A rapid and complete destruction of organics in the supercritical water oxidation (SCWO) of the Co-exchanged resin was found experimentally. Due to an extremely low solubility of CoSO4 salt formed and separated effectively in the SCWO process, a minimal release of the nuclide Co would be warranted. In addition, recycling of Co nuclides is also possible by decomposition of the CoSO4 species at elevated temperatures (> 1040 K).

Carbon Monoxide↗