Biomedical subjects

B J Liu

Publications and source records attributed to B J Liu.

11 recordsLinked to original sources

PubMed2006

Search for invisible decays of eta and eta' in J/psi --> phi eta and phi eta'.

Using a data sample of 58 x 10(6) J/psi decays collected with the Beijing Spectrometer II detector at the Beijing Electron Positron Collider, searches for invisible decays of eta and eta' in J/psi to phi eta and phi eta' are performed. The phi signals, which are reconstructed in K+K- final states, are used to tag the eta and eta' decays. No signals are found for the invisible decays of either eta or eta', and upper limits at the 90% confidence level are determined to be 1.65 x 10(-3) for the ratio B(eta-->invisible)/B(eta --> gamma gamma) and 6.69 x 10(-2) for B(eta' --> invisible)/B(eta' --> gammagamma). These are the first searches for eta and eta' decays into invisible final states.

Journal Article↗

PubMed2006

Observation of a near-threshold enhancement in the omega(phi) mass spectrum from the doubly OZI-suppressed decay J/psi-->gamma(omega)phi.

An enhancement near threshold is observed in the omega(phi) invariant mass spectrum from the doubly Okubo-Zweig-Iizuka-suppressed decays of J/psi-->gamma(omega)phi, based on a sample of 5.8 x 10(7) J/psi events collected with the BESII detector. A partial wave analysis shows that this enhancement favors JP=0+, and its mass and width are M=1812(+19)(-26)(stat)+/-18(syst) MeV/c2 and Gamma=105+/-20(stat)+/-28(syst) MeV/c2. The product branching fraction is determined to be B(J/psi-->gammaX)B(X-->omega(phi))=[2.61+/-0.27(stat)+/-0.65(syst)]x10(-4).

Journal Article↗

PubMed2003

Trends in PACS image storage and archive.

PACS is widely used in hospitals and is considered a mission critical system for around-the-clock daily clinical operation. Scheduled or unscheduled downtime of the main PACS archive storage or server could potentially cripple the entire PACS operation. This is especially the case in a filmless hospital environment. Therefore, in a downtime event, it is most desirable for users to have only a minimal performance impact without interruption of clinical data flow or loss of data and to have available historical PACS studies. This paper summarizes some of the developments in the design and implementation of a reliable PACS that insures maximum uptime for end users while preserving the integrity of the PACS data and making it available during downtime events. It also details strategy for developing proper clinical workflow contingency procedures when a scheduled downtime event to the main archive storage and server occurs. Specifically, the design and implementation of a fault-tolerant (FT) main archive server, the development of a FT back-up archive using an application service provider (ASP) model, and the clinical experiences while upgrading a main archive server and migrating the stored PACS data to new storage media will be discussed.

California↗

PubMed2003

Database of repetitive elements in complete genomes and data mining using transcription factor binding sites.

Approximately 43% of the human genome is occupied by repetitive elements. Even more, around 51% of the rice genome is occupied by repetitive elements. The analysis presented here indicates that repetitive elements in complete genomes may have been very important in the evolutionary genomics. In this study, a database, called the Repeat Sequence Database, is first designed and implemented to store complete and comprehensive repetitive sequences. See http://rsdb.csie.ncu.edu.tw for more information. The database contains direct, inverted and palindromic repetitive sequences, and each repetitive sequence has a variable length ranging from seven to many hundred nucleotides. The repetitive sequences in the database are explored using a mathematical algorithm to mine rules on how combinations of individual binding sites are distributed among repetitive sequences in the database. Combinations of transcription factor binding sites in the repetitive sequences are obtained and then data mining techniques are applied to mine association rules from these combinations. The discovered associations are further pruned to remove insignificant associations and obtain a set of associations. The mined association rules facilitate efforts to identify gene classes regulated by similar mechanisms and accurately predict regulatory elements. Experiments are performed on several genomes including C. elegans, human chromosome 22, and yeast.

Algorithms↗

PubMed2001

[Study of direct determining animal and plant oil in sewage by ultraviolet spectrophotometry method].

In this paper, the trace oil in sewage have been emulsified with S-T emulsifier and determined by ultraviolet spectrophotometry. Under normal temperature, the oil even dispersed in sewage with S-T emulsifier. It is stable and direct determined without separation. The oil is from sewage. The linear range is 0-92 micrograms.mL-1, and rate of recovery is 89%-129%. The method is quick and simple.

Animals↗

PubMed1996

Alteration of dopamine release by rat caudate putamen tissues superfused with alpha 2-macroglobulin.

Monoamine-activated alpha-2-macroglobulin (alpha 2M) has been shown to decrease the dopamine concentrations in rat caudate putamen (CP) in vivo as well as inhibit choline acetyltransferase activities in the culture of basal forebrain neurons. In this study, we further investigated the effects of methylamine-activated alpha 2M (MA-alpha 2M) upon striatal dopaminergic function by determining whether a direct infusion of this glycoprotein will alter dopamine (DA) release in vitro from superfused CP tissue fragments. In experiment 1, an infusion of 2.8 microM MA-alpha 2M produced a statistically significant increase in DA release compared with control superfusions. In experiment 2, varying doses (0, 0.7, 1.4, 2.8, 4.1 microM) of MA-alpha 2M were tested for their capacity to alter DA release. Only the 2.8 microM dose of MA-alpha 2M was effective in producing a significant increase of DA release. In experiment 3, the normal form of alpha 2M (N-alpha 2M) at 2.8 microM was compared with the control superfusions. The infusion of N-alpha 2M produced an increase in DA release which was substantially lower than the DA increase induced by MA-alpha 2M, and not significantly different from that of the control superfusion. These results show that MA-alpha 2M, like some other neurotoxins, can markedly alter CP dopaminergic function as indicated by the acute increase in DA release following infusion of this glycoprotein, and these effects are exerted at a relatively narrow range of doses. Taken together, these data suggest that this glycoprotein, if allowed to accumulate in the central nervous system (CNS), may promote some neurodegenerative changes that can occur in disorders like Parkinson's disease.

Alzheimer Disease↗

PubMed1996

Effect of phencyclidine on dog coronary artery.

AIM: To study the effect of phencyclidine (Phe) on dog coronary artery. METHODS: Contraction of spiral strips of dog coronary artery in bioassay and coronary artery blood flow (CBF) using electromagnetic flowmeter on anesthetized dogs were observed. RESULTS: Phe 0.1-100 mumol.L-1 induced contraction of strips in a concentration-dependent manner. Dextromethorphan (Dex) 10 mumol.L-1, an antagonist of Phe receptor, antagonized the action of Phe. In vivo, Phe 10 mg.kg-1 increased flow of left circumflex coronary artery of anesthetized dogs from 334 +/- 35 mL.kg-1.min-1 to 510 +/- 58 mL.kg-1.min-1, and both left ventrical pressure (LVP) and blood pressure (BP) rose slowly after medication. Dextromethorphan (Dex) 5 mg.kg-1 also antagonized the effect of Phe. CONCLUSION: The regulation of Phe on coronary artery in vivo differs from that in vitro, which may result in the contradictory effects.

Animals↗

PubMed1994

Noise content analysis in clinical digital images.

Most digital modalities in radiology use 12 bits precision to store the digital images. To determine whether all these bits contain useful information, a statistical method called the Moran test was used to measure the noise level in computed tomographic, magnetic resonance, and digital radiographic images. The test was performed on the bit planes of each pixel. After the noise level was estimated, the pixel data were separated into signal bits and noise bits, and image enhancement techniques were applied on the noise-bits-removed images to demonstrate that the removal of noise bits did not affect image quality. Preliminary results showed no noticeable difference between the original images and the noise-bits-removed images.

Algorithms↗

PubMed1994

Effects of antipsoriatic drugs on biosynthesis of platelet activating factor by human keratinocytes.

Human keratinocytes in primary culture stimulated by Ca2+ ionophore A23187(Io) could synthesize and release a material which might aggregate aspirin-treated washed rabbit platelets and was identified as platelet activating factor (PAF) by four methods. Io stimulated the production of PAF by keratinocytes in a time- and dose-dependent manner. The PAF precursors, i.e., AAGPC and Lyso-PAF, were detected in keratinocytes. Nitrogen mustard and dexamethasone could time- and dose-dependently inhibit PAF biosynthesis from Io to induce human keratinocytes in culture. The IC50 of nitrogen mustard and dexamethasone were 6.34 x 10(-9) M and 1.005 x 10(-8) M respectively. The results showed that the synthesis and release of PAF by normal human keratinocytes may be accounted for the development of cutaneous inflammation and the pathogenesis of some skin disorders and application of drugs that inhibit PAF synthesis may be a new and effective approach to the management of some inflammatory skin diseases such as psoriasis.

Calcimycin↗

PubMed1994

[The characterization of 5-HT1A receptor in the central nervous system of the spontaneously hypertensive rats].

With method of the radio binding assay (RBA), it was observed that in the present work that in normotensive Wistar rats, the specific binding of [3H] 8-OH-DPAT at 2.4 nmol/L concentration was about the same in hippocampus (7.62 +/- 0.24 pmol/mg), hypothalamus (8.18 +/- 0.63 pmol/mg) and lower brain stem (9.11 +/- 0.78 pmol/mg); whereas, in spontaneously hypertensive rats (SHR), these regional specific bindings were 2(+)-3+ times higher. Scatchard analyses showed that the Bmax was also higher than that of normotensive Wistar rats in hippocampus and hypothalamus, whereas the KD in hypothalamus was lower. The differences between SHR and normotensive rats in the 5-HT1A receptor contents in various brain regions appear to be related to one of the linking events in the generation of hypertension.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed1994

[Effect of BN52021 on platelet activating factor induced aggregation of psoriatic polymorphonuclear neutrophils].

We investigated the aggregation of PMN from 20 psoriasis patients (PP) and 12 health persons (HP) to PAF and the effect of PAF antagonist BN 52021 on the aggregation. PAF induced a dose dependent aggregative response of polymorphonuclear neutrophils (PMN) from PP and HP. The aggregative responses of PMN from PP to lower concentrations of PAF were increased (P < 0.05) and to higher concentrations of PAF were not different to that of PMN from HP. BN 52021 could time- and dose-dependently inhibit the aggregation of PMN from PP and HP to PAF, and their IC50 was 1.3 x 10(-6) mol and 1.2 x 10(-6) mol respectively. It is suggested that PAF and PMN play an important pathophysiological role in the development of psoriasis, and application of PAF antagonists may be a new and effective approach to the management of psoriasis.

Adult↗