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Biomedical subjects

Y H Liu

Publications and source records attributed to Y H Liu.

At least 19 recordsLinked to original sources
PubMed2006

Observation of fluorescence emissions from single-bubble sonoluminescence in water doped with quinine.

Sonoluminescence is a phenomenon involving the transduction of sound into light. The detailed mechanism as well as the energy-focusing potentials are not yet fully explored and understood. So far only optical photons are observed, while emissions in the ultra-violet range are only inferred. By doping the fluorescent dye quinine into water with dilute sulphuric acid, the high energy photons can be converted into the optical photons with slower decay constants. These sonoluminescence and fluorescent emissions were observed in coincidence, and the emitted signals of the two modes can be differentiated by their respective timing profiles. Plans for using this technique as a diagnostic tool to quantitatively study ultra-violet and other high energy emissions in sonoluminescence are discussed.

Dose-Response Relationship, Radiation↗
PubMed2006

Structure of multispecies charged particles in a quadratic trap.

Multispecies interacting charged particles in a two-dimensional quadratic trap are studied. The ground-state configurations for different particle and species numbers are obtained by molecular dynamics simulation. It is found that particles with similar mass-to-charge ratio tend to populate a common shell, whose location depends on the particle mass-to-charge ratio, and that the greater the latter, the closer are the particles to the center of the trap. This scaling for the ground-state configuration is independent of the total particle and species numbers in the system.

Journal Article↗
PubMed2006

Modified neodymium-YAG laser in rigid bronchoscopy.

The use of laser bronchoscopy in the treatment of tracheobronchial stenosis has been reported in the past. It is generally safe and effective; however, the complications of haemorrhage, airway perforation, or airway fire are relatively frequent among less experienced surgeons. We illustrate a modified technique of laser probe location to simplify the laser ablation procedure.

Adult↗
PubMed2006

Effects of particle size and physical form of diets on mast cell numbers, histamine, and stem cell factor concentration in the small intestine of broiler chickens.

The aim of this study was to investigate the hypothesis that particle size and diet form may affect the growth of mast cells and histamine release from the small intestine of broiler chickens. A total of 288, day-old male broiler chicks were randomly allocated to 1 of 4 corn-soy diets in a 2 x 2 factorial design. The factors included particle size (coarse vs. fine) and physical form (mash vs. pellet). The birds were housed in 90 x 60 cm pens containing 12 birds, and each treatment contained 6 replicate pens of birds from d 1 to 22. On d 22, 6 broilers from each treatment were slaughtered. Tissues from the small intestine (duodenum, jejunum, and ileum) were obtained to quantify mast cells using the toluidine blue staining technique. The results showed that mast cells in the jejunum were concentrated in the upper part of the villus in birds fed the coarsely ground mash diet, whereas mast cells were evenly distributed throughout the intestine in birds fed the other 3 diets. The number of mast cells was significantly lower in the duodenum (P = 0.04), jejunum (P < 0.01), and ileum (P = 0.01) of birds fed coarsely ground diets compared with finely ground diets, and there was no difference in mast cell numbers between birds fed mashed or pelleted diets at any site in the intestine. The histamine content (P = 0.02) and stem cell factor concentration (P = 0.03) were markedly lower in the jejunum of birds that were fed coarsely ground diets compared with finely ground diets. The stem cell factor concentration in the duodenum (P < 0.01) and jejunum (P = 0.05) was higher in birds fed pelleted compared with mash diets. The overall results of this experiment suggest that particle size and diet form affect mast cell number and histamine content in the small intestine by regulation of stem cell factor concentration.

Animal Feed↗
PubMed2006

[Distribution of hepatitis B virus genotypes in Guizhou and analysis of clinical significance.].

BACKGROUND: To investigate the distribution of HBV genotypes in Guizhou and study the relationship between the genotype and the progression of liver disease. METHOD: Totally 693 patients with chronic HBV infection, from 4 areas of Guizhou, including 292 asymptomatic HBV carriers (ASC), 276 cases with chronic hepatitis (CH), 76 liver cirrhosis (LC), 49 hepatocellular carcinoma (HCC) were examined. The HBV genotype was determined by restriction fragment length polymorphism analysis and the relationship between HBV genotype and the progression of liver disease was studied by multifactor analysis such as HBsAg positivity, HBV DNA load and ALT level. RESULTS: Of the 693 patients, 6 (0.87%), 449 (64.79%), 233 (33.62%), and 5 (0.72%) belonged to genotype A, B, C and D, respectively. There was a statistically siganificant difference in the distribution of genotype B among Kaili (96.4%), Zunye (78.79%), Duyun (76.19%) and Guiyang (53.66%) areas (P less than 0.01). Genotype C was more prevalent in Guiyang than in other three areas (45.68% vs. 23.8%, 45.68% vs. 13.13%, 45.68% vs. 3.96%, P less than 0.01, respectively). There were also statistically significant difference in distribution of genotype B and C in various stages of liver disease (P less than 0.01). Genotype B showed a decreasing trend from ASC, CH, LC to HCC and genotype C was more frequent in patients with CH (45.92%) than in those with ASC (20.6%), LC (17.17%) and HCC (16.31%). The ALT levels and the mean ages were significantly higher and older in patients with genotype C than those in genotype B. The HBeAg positivity was significantly lower in genotype C than that in genotype B (48.07% vs 61.90%, P less than 0.01). CONCLUSION: Genotype A, B, C and D exist in Guizhou. Genotype B predominates and genotype C was the second common. The geographic distribution of genotype B and C are different in some areas of Guizhou. Compared with genotype B, genotype C is associated with the development of more severe liver damage.

China↗
PubMed2005

Identification of a novel HLA-DRB1 allele (HLA-DRB1*111902*).

In this paper, we report a new HLA-DRB1 allele identified in a male acute myeloid leukaemia Chinese patient. This sample was initially typed as DRB1*11XX using commercial polymerase chain reaction-sequence-specific primers kit. When it was typed using a chip-based sequence-specific oligonucleotide technique, a novel hybridization pattern that does not match any known alleles was observed. Through sequencing, we have identified this allele as a new HLA-DRB1 allele, which was later named HLA-DRB1*111902 by the WHO Nomenclature Committee. The sequence of this new allele differs from DRB1*111901 by one nucleotide (from G to C) at 203nt of exon 2 but does not cause any amino acid substitution.

Alleles↗
PubMed2005

The prevalence of PD in a nutritionally deficient rural population in China.

OBJECTIVES: In most reports, the prevalence of PD in mainland China is lower than in western populations. To estimate PD prevalence in China, we performed a cross-sectional study in a rural population in Linxian County, China. PRIMARY OUTCOMES: Clinical diagnosis of PD. RESULTS: Among the 16,488 participants examined, the overall age- and gender-adjusted prevalence rate of PD was 522/100,000 (95% CI: 477-567) assuming no cases of PD would be found among those younger than 50 years of age. The gender-adjusted prevalence rates were 103 (95% CI: 83-123), 621 (95% CI: 572-670), 902 (95% CI: 843-961), and 1744 (95% CI: 1662-1826) per 100,000 in age groups 50-59, 60-69, 70-79, and 80 and above, respectively. CONCLUSIONS: The estimated prevalence of PD in Linxian, China is higher than most of those reported from other areas in China, and similar to those reported from non-Asian populations.

Age Distribution↗
PubMed2005

Molecular epidemiology of Mycobacterium tuberculosis in China: a nationwide random survey in 2000.

OBJECTIVE: To determine the contribution of the Mycobacterium tuberculosis (TB) Beijing genotype to the population structure of M. tuberculosis complex in China. DESIGN: Genotypes of 441 mycobacterial isolates were determined by spoligotyping and IS6110 restriction fragment length polymorphism (RFLP). The isolates were from a nationwide random survey for the epidemiology of TB conducted in 2000, and the drug susceptibility patterns and epidemiological data were known. RESULT: A total of 408 samples contained M. tuberculosis as determined by spoligotyping. Of the M. tuberculosis strains, 64.9% (265/408) were of the Beijing genotype. Using the chi-squared test, no statistically significant differences were observed in the proportion of Beijing genotype TB in patients of different sex, age or living in different areas of the country, but a significant difference was observed with multidrug-resistant (MDR) TB: 77.8% (42/ 54) of MDR isolates were of the Beijing genotype vs. 60.2% (213/354) of the drug-susceptible isolates. In the multivariate logistic regression model, the Beijing genotype was significantly associated with region and not with MDR. CONCLUSION: The M. tuberculosis Beijing genotype has prevailed in China for at least five decades and is associated with region.

Adolescent↗
PubMed2004

Multicentric reticulohistiocytosis with generalized systemic involvement.

We describe a 33-year-old woman with a 2-year history of rheumatoid arthritis-like joint changes and a 1-year history of papulonodules on the fingers, ears, oral mucosa, forearm, elbows and thighs, and erythematous plaques on the buttocks. Six months after the onset of the cutaneous lesions she had dyspnoea, 3 months later she developed a husky sound. Biopsies from the nodules on the ear and left forearm revealed multinucleated giant cells with eosinophilic 'ground-glass' cytoplasm. Bronchoscopy revealed that there were nodules in the bronchus. A biopsy taken from a nodule from the bronchus was consistent with multicentric reticulohistiocytosis. Fibrostic laryngoscopy showed a mass 1.5 x 2.0 cm(2) in size on the left aryepiglottic fold and posterior commissure. Magnetic resonance imaging revealed a large pleural effusion and pericardiac effusion. Ultrasound revealed splenomegaly and peritoneal fluid. Combination therapy with prednisone, cyclophosphamide and methotrexate significantly improved cutaneous and joint symptoms. The huge cutaneous erythematous plaques and the generalized systemic involvement make this case interesting.

Adult↗
PubMed2004

Attention-deficit/hyperactivity disorder: evidence-based diagnosis and management for primary care clinicians.

Attention-deficit/hyperactivity disorder (ADHD) is a disorder characterized by persistent hyperactivity, impulsivity and inattention that impairs educational achievement and/or social development. Families seek an evaluation for children with these behaviors due to the high prevalence of ADHD and potential personal, social, and economic burdens. This review covers the current state of knowledge regarding the epidemiology, etiology, diagnosis, treatment, and prognosis for ADHD. It concludes with recommendations for future research.

Adolescent↗
PubMed2003

Evaluation of influent prefermentation as a unit process upon biological nutrient removal.

The objective of this NSF sponsored research was to provide a controlled comparison of identical continuous flow biological nutrient removal (BNR) processes both with and without prefermentation in order to provide a stronger, more quantitative, technical basis for design engineers to determine the potential benefits of prefermentation to EBPR in treating domestic wastewater. Specifically, this paper focused upon the potential impacts of primary influent prefermentation upon BNR processes treating septic domestic wastewater. This study can be divided into two distinct phases--an initial bench-scale phase which treated septic P-limited (TCOD:TP>40) wastewater and a subsequent pilot-scale phase which treated septic COD-limited (TCOD:TP<40) wastewater. The following conclusions can be drawn from the results obtained to date. Prefermentation increased both RBCOD, SBCOD and VFA content of septic domestic wastewater. Prefermentation resulted in increased biological P removal for a highly septic, non-P limited (TCOD:TP<40:1) wastewater. However, in septic, P-limited (TCOD:TP>40:1) wastewater, changes in net P removal due to prefermentation were suppressed by limited P availability, even though P release and PHA content were affected. Prefermentation increased specific anoxic denitrification rates for both COD and P-limited wastewaters, and in the pilot (COD-limited) study also coincided with greater system N removal.

Bioreactors↗
PubMed2003

Polyhydroxyalkanoate form and polyphosphate regulation: keys to biological phosphorus and glycogen transformations?

Experimental studies with both synthetic and real domestic wastewater showed that poly-3-hydroxy-butyrate (3HB) and poly-3-hydroxy-valerate (3HV) formed in direct proportion to the acetate/propionate (Ace/Pro) ratio of the influent wastewater during Enhanced Biological Phosphorus Removal (EBPR). Acetic acid resulted in higher anaerobic phosphorus (P) release, polyhydroxyalkanoate (PHA) yield, 3HB content, and glycogen (CH) degradation. Linear regression showed that anaerobic P release (Prel) and CH degradation (CHdeg) were both a function of Ace-->3HB, but not of Pro-->3HV. Aerobic P uptake (Pup) correlated best with preceding Prel, rather than PHA (but note Prel correlated with Ace-->3HB). Aerobic CH formation (CHform) correlated best with CHdeg and 3HB. The results imply the acetate/propionate content of influent has a major influence on PHA, CH, and P transformations. Short-term increases in acetic or propionic acid increased Prel, but were always offset by corresponding changes in Pup to yield the same net P removal as the control reactor. Thus net P removal, and EBPR process performance, was probably a function of the population selected (i.e. XPAO fraction) during long-term cultivation.

Bacteria, Anaerobic↗
PubMed2002

YY1 activates Msx2 gene independent of bone morphogenetic protein signaling.

Msx2 is a homeobox gene expressed in multiple embryonic tissues which functions as a key mediator of numerous developmental processes. YY1 is a bi-functional zinc finger protein that serves as a repressor or activator to a variety of promoters. The role of YY1 during embryogenesis remains unknown. In this study, we report that Msx2 is regulated by YY1 through protein-DNA interactions. During embryogenesis, the expression pattern of YY1 was observed to overlap in part with that of Msx2. Most notably, during first branchial arch and limb development, both YY1 and Msx2 were highly expressed, and their patterns were complementary. To test the hypothesis that YY1 regulates Msx2 gene expression, P19 embryonal cells were used in a number of expression and binding assays. We discovered that, in these cells, YY1 activated endogenous Msx2 gene expression as well as Msx2 promoter-luciferase fusion gene activity. These biological activities were dependent on both the DNA binding and activation domains of YY1. In addition, YY1 bound specifically to three YY1 binding sites on the proximal promoter of Msx2 that accounted for this transactivation. Mutations introduced to these sites reduced the level of YY1 transactivation. As bone morphogenetic protein type 4 (BMP4) regulates Msx2 expression in embryonic tissues and in P19 cells, we further tested whether YY1 is the mediator of this BMP4 activity. BMP4 did not induce the expression of YY1 in early mouse mandibular explants, nor in P19 cells, suggesting that YY1 is not a required mediator of the BMP4 pathway in these tissues at this developmental stage. Taken together, these findings suggest that YY1 functions as an activator for the Msx2 gene, and that this regulation, which is independent of the BMP4 pathway, may be required during early mouse craniofacial and limb morphogenesis.

Animals↗
PubMed2002

Application of narrow band laser ultrasonics to the nondestructive evaluation of thin bonding layers.

In this paper, a modified laser induced grating technique (LIG) has been utilized to generate narrow band surface waves in an epoxy-bonded copper-aluminum layered structure. A high performance optical interferometer system was utilized to detect the laser-generated surface waves. The dispersion of surface wave in an epoxy-bonded copper-aluminum specimen was measured and compared with the theoretical solution. An inverse algorithm based on the simplex method was then introduced to determine the bonding thickness as well as the elastic properties of the bonding layer. The inversion results demonstrated that the thickness in the microm range or the elastic properties of the bonding layer could be successfully determined.

Journal Article↗
PubMed2001

[Establishment of rabbit model for peritoneal dialysis related peritonits].

OBJECTIVE: To establish a rabbit model corresponding with clinical characteristics of peritoneal dialysis related peritonitis. METHODS: Twelve New Zealand rabbits were randomly divided into peritonitis group and control group. They were infused standard living Staphylococcus aureus 3 x 10(9) colony forming unit (cfu) (peritonitis group) or 0.9% NaCl 1 ml (control group). After 48 hours, Laboratory rabbits in acute uremic model underwent regular dialysis for 6 hours. At different points of time, the concentration of glucose in dialysate and the dialysate/plasma (D/P) ratio of the concentration creatinine (Cr), total protein(TP), album(Alb) and IgG, the counts of leukocyte in dialysate and water ultrafiltrate were determined. RESULTS: D/D0 were significantly lower in the peritonitis group than that in the control group (P < 0.05). The counts of leukocyte and D/P ratio of Cr, TP, Alb and IgG were significantly increased in the peritonitis group (all P < 0.05). The drained volume was lower in the peritonitis group than that in the control group (but P > 0.05). CONCLUSION: In the rabbit model infused intraperoneally staphylococcus aureus, (1) transport peritoneum of low and large molecular weight solutes is increased, (2) the volume of ultrafiltrate is decreased, (3) the counts of leukocyte in dialysate is increased. These change in this model is basic all correspond with the clinical feature of patients of peritoneal dialysis related peritonitis. So this rabbit model of peritoneal dialysis related peritonitis is a successful experimental infection model.

Animals↗
PubMed2001

Assembly of a robust, thermally stable porous cobalt(II) nicotinate framework based on a dicobalt carboxylate unit.

A series of robust, thermally stable open-framework cobalt nicotinate compounds, Co(2)(H(2)O)[C(6)H(4)O(2)N](4).0.5CH(3)CH(2)OH.0.5H(2)O (1), Co(2)(H(2)O)[C(6)H(4)O(2)N](4) (2), and Co(2)(H(2)O)[C(6)H(4)O(2)N](4).C(6)H(5)CH(2)OH (3), based on rigid dimetallic carboxylate clusters as the basic building unit have been prepared. Single-crystal X-ray crystallographic analyses of 1 and 3 reveal the host framework possessing an effective channel area with the dimensions of 10.8 x 4.5 A. These channels can accommodate guest molecules of various sizes and shapes such as ethanol, water, and benzyl alcohol. Thermogravimetric analysis shows a two-step weight loss corresponding to the loss of guest molecules followed by the loss of coordinated water. The host framework is thermally stable up to 295 degrees C. The cobalt nicotinate host remains intact, even upon the removal of the guest to form compound 2 as revealed by single-crystal X-ray diffraction analysis. Crystal data for 1: Co(2)(H(2)O)[C(6)H(4)O(2)N)](4).0.5CH(3)CH(2)OH.0.5H(2)O, fw = 656.33, triclinic, space group P(-)1, a = 10.5407(2) A, b = 11.8266(3) A, c = 14.1122(2) A, alpha = 106.878(4) degrees, beta = 102.411(2) degrees, gamma = 111.011(3) degrees, V = 1467.9(5) A(3), Z = 2. Crystal data for 2: Co(2)(H(2)O)[C(6)H(4)O(2)N](4), fw = 624.28, triclinic, space group P(-)1, a = 10.507(3) A, b = 11.824(2) A, c = 14.113(3) A, alpha = 107.06(2) degrees, beta = 102.39(2) degrees, gamma = 111.105(16) degrees, V = 1459.5(6) A(3), Z = 2. Crystal data for 3: Co(2)(H(2)O)[C(6)H(4)O(2)N](4).C(6)H(5)CH(2)OH, fw = 732.42, triclinic, space group P(-)1, a = 10.6671(6) A, b = 12.0063(7) A, c = 14.0658(8) A, alpha = 106.7180(10) degrees, beta = 102.2790(10) degrees, gamma = 111.1900(10) degrees, V = 1504.1(6) A(3), Z = 2. The magnetic exchange coupling between the dicobalt centers for compounds 1 and 3 are analyzed on the basis of both the Curie-Weiss expression and a binuclear magnetic model. The negative values of the magnetic exchange coupling constant indicate the antiferromagnetic nature within the cobalt dimer.

Journal Article↗