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Biomedical subjects

W X Lu

Publications and source records attributed to W X Lu.

At least 19 recordsLinked to original sources
PubMed2006

Assembly of disperse red 1 molecules in the channels of AlPO4-5 single crystals for second-harmonic generation.

Disperse red 1 (DR1) molecules have been successfully incorporated into the one-dimensional channels of AlPO4-5 single crystals by means of vapor-phase diffusion. Polarizing microscope and SHG results indicate that the DR1 molecules are well aligned in a preferred direction along the crystal channels. The p-polarization (parallel to the c-axis of AlPO4-5 crystal) SH intensity (Ip-ex), and s-polarization (perpendicular to the c-axis of AlPO4-5 crystal) SH intensity (Is-ex) of DR1-loaded AlPO4-5 single crystals can be well fitted as a function of input polarization angle (alpha): Ip-ex = 0.69 cos4 alpha + 0.37 sin4 alpha - 0.17, Is-ex = 0.69 cos2 alpha sin2 alpha + 0.06, respectively. This polarization angle dependence can be well explained by three different SHG processes of Ip (0 degrees), Ip (90 degrees), and Is (45 degrees), originated from different combinations of two polarized photons.

Journal Article↗
PubMed1991

On two weighted signal averaging methods and their application to the surface detection of cardiac micropotentials.

In this paper, the variance normalized averaging (VNA) and the optimal weighted averaging (OWA) are derived and their application to the surface detection of cardiac micropotentials is discussed. Theoretical analysis and computer simulation showed that VNA and OWA are superior to the conventional signal averaging (CSA) in reducing random noise with changing variance and the larger the change of noise variance the better the improvements of VNA and OWA relative to CSA. Clinical application of VNA and OWA using a proposed noise variance estimation technique indicated that residual noise on the PR and ST segments can be further reduced in most of the cases. This manifests that the new techniques have a potential advantage for improving the effectiveness of signal averaging as a fundamental method for surface detection of cardiac micropotentials.

Computer Simulation↗
PubMed1990

[Diagnosis of cyanosis and digital clubbing caused by liver cirrhosis].

Six cases of cyanosis and digital clubbing caused by liver cirrhosis were reported. The mean levels of PaO2 and PaCO2 were 6.4 +/- 0.8 kPa (48.3 +/- 6.2 mmHg) and 3.9 +/- 0.8 kPa (29.5 +/- 6.1 mmHg) respectively. The cause of cyanosis and digital clubbing in liver cirrhosis was discussed. Abnormal intrapulmonary shunting (IPS), which was proved in 4 cases by whole-body radionuclide scanning with 99mTc-MAA, is suggested as the major cause of cyanosis in liver cirrhosis. Clinically IPS is usually associated with debilitating conditions characterized by hyperventilation, abnormality of lung diffusion and orthodeoxia or platypnea. The authors suggest that whole-body radionuclide scanning with 99mTc-MAA may be performed for establishing IPS if liver cirrhosis is highly suspected to be the cause of severe hypoxemia.

Adult↗
PubMed1990

[Diagnosis and treatment of chronic eosinophilic pneumonia].

A case of chronic eosinophilic pneumonia (CEP), confirmed by transfibroptic bronchoscope lung biopsy, was reported. CEP is a chronic interstitial lung disease characterized by cough, dyspnea, malaise, fever, night sweats, weight loss, variable degree of blood eosinophilia and film revealing peripheral nonsegmental nonmigratory infiltrates. It usually responds dramatically to corticosteroids. The authors suggested that a tentative diagnosis is often made on clinical grounds only without biopsy confirmation and corticosteroid therapy is instituted. It is necessary to perform lung biopsy for establishing the diagnosis when the patient has normal eosinophilic count, nonpheripheral lung infiltrats or other atypical manifestations.

Biopsy↗
PubMed1989

[Evaluation of the causative bacteria of pneumonia in the elderly in recent years].

A study of 62 cases of elderly pneumonia (EP) in their sixties and eighties with etiologic bacteria confirmed by cultures of sputum, blood or pleural effusion was carried out Greater change of etiologic bacteria of EP in patients of eighties has been found when they were compared with those of sixties. In the group of eighties the incidence of Gram-negative bacilli increased (77%), including pseudomonas aeruginosa (48.39%), Klebsiella pneumoniae (17.35%) and Enteric coli (9.68%), while Staphylococcus aureus accounted only for 16.1%. There were 2 species of Streptococcus pneumoniae; both were mixed with other bacteria in cultures. In patients of eighties the etiologic agents isolated from pneumonia were more resistant to many common antibiotics. The above mentioned results suggest that the diagnosis of etiology of pneumonia in the elderly should be emphasized.

Aged↗
PubMed1988

Parameters of exponentially damped sinusoids in noise and their application to the analysis of visual evoked potentials.

The backward prediction and singular value (SV) truncation methods for estimating multiple exponentially damped real sinusoids in noise have been studied. The basic theory and algorithm are outlined, and the effect on the error of computational parameters, such as the sampling window, the sampling rate, the order of the prediction-error filter (PEF) and the truncated point of SV, were studied using simulated data. If the computational parameters are carefully chosen, the estimate of frequency and damping factor of a damped sinusoid is quite accurate (within a certain range of signal to noise (S/N) ratio). We use this method to estimate the parameters of visual evoked potentials (VEP) and then reconstructed them from estimated parameters according to the resonant model. The error between original VEP and the reconstructed waveform is within 5%. This method can be used in the analysis and recognition of various systems.

Algorithms↗
PubMed1986

An endogenous ligand for phencyclidine receptors: isolated from human brains.

Using preparative HPLC, Sephadex G-25 and analytic HPLC, we obtained an active peak inhibiting (3H) PCP receptor binding, with a molecular weight of 3,000 daltons. Another isolation process included acetic acid extraction, Toyopearl HW gel filtration, Sephadex G-10 chromatography and analytic HPLC. An active peak was also observed, which was consistent with that from the first isolation process.

Brain↗
PubMed1985

The analgesic and respiratory depressant actions of metorphamide in mice and rabbits.

Metorphamide (MET) elicited a potent, dose-dependent analgesia and respiratory depression in mice and rabbits. MET induced-analgesia was naloxone reversible and potentiated by bestatin. Naloxonazine, a relatively selective mu 1 blocker, at certain dosage (50 micrograms per rabbit, icv), could abolish the analgesia but not the respiratory inhibition produced by MET. Our result indicates that mu 1 receptors mediate the MET induced-analgesia but not its respiratory effect. Since MET is a mu- and kappa-ligand with very low delta activity, the MET induced respiratory depression may be mediated by mu 2 or kappa binding sites.

Analgesics↗