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Biomedical subjects

X Z Zhao

Publications and source records attributed to X Z Zhao.

At least 19 recordsLinked to original sources
PubMed2003

Ultrasonic transducers using electron-irradiated vinylidene fluoride-trifluoroethylene copolymers.

Single-element, planar transducers have been fabricated using electron-irradiated poly(vinylidene fluoride-trifluoroethylene) 80/20 mol% copolymers with different electron dosage. Electrical field-induced strain response of copolymer film with 100 Mrad dosage has been studied at 5 kHz and the electrostrictive coefficient was calculated. The transmitting response of the air-backing and epoxy-backing transducers was evaluated with the application of high DC bias voltages. Clear ultrasonic amplitudes and high frequency spectrum (>20 MHz) were observed when driven from a standard ultrasonic voltage source through a decoupling circuit. It has also showed that larger generation of ultrasonic waves will be induced under high DC bias field, which is due to the increase of induced d(33) piezoelectric coefficient. Two different polar bias voltages, positive and negative, were applied to the transducers and inverse waveforms were received, which was coincident with the theoretical analysis of the strain response of electrostrictive film.

Journal Article↗
PubMed1998

[Pupillary responses evoked by spatial patterns].

Human pupillary responses evoked by visual spatial patterns were investigated. Experimental data revealed that: (1) pupillary constriction can be induced not only by increment of luminance but also by change of gratings or checkerboards without change of space-averaged luminance; (2) constriction amplitude increases with increasing difference of spatial frequency; (3) pupillary response can be evoked by changing from uniform brightness to checkerboard patterns or from checkerboard to darkness, without any increment of the local luminance. These results indicate that the human pupillary response system is not merely controlled by luminous flux but also receives and processes visual pattern information.

Evoked Potentials, Visual↗
PubMed1994

[Experimental studies on transmission of EHF in rodents].

Studies on the possible routes of transmission of epidemic hemorrhagic fever (EHF) were conducted in experimental animals. Results showed five-ID50/ml of EHF virus (EHFV) suspension could infect rats through their damaged skin. Both gamasid mites and mower's mites collected from epidemic areas could naturally infect and transmit EHFV by biting and stinging, or transmit transovarially. EHFV excreted from the experimentally infected animals could be transmitted to normal ones by aerosol. Experimental rats could be infected with EHFV via damaged mucous membrane of the digestive tract. The above results suggested the main route of transmission of EHFV was via damaged skin. Mite-borne transmission played an important role in perpetuating natural foci of EHF in rats. Respiratory transmission of EHFV via aerosol also was a possible route of transmission under specific conditions. In general, EHFV could hardly be transmitted via digestive tract. All those mentioned above provided an important scientific basis for prevention of EHF.

Animals↗
PubMed1992

[Effects of Astragalus membranaceus and Tripterygium hypoglancum on natural killer cell activity of peripheral blood mononuclear in systemic lupus erythematosus].

Natural killer (NK) activity of peripheral blood mononuclear cells (PBMC) from 28 patients with systemic lupus erythematosus (SLE) was measured using enzyme-release assay. The SLE patients had significantly decreased NK activity in comparing with normal controls. The levels of NK activity correlated with disease activity. Pre-incubation of PBMC separately with Astragalus membranaceus and Tripterygium hypoglaucum or with their mixture considerably stimulated NK cytotoxicity both in SLE patients and healthy donors. The extent of enhancement was dose-dependent and relevant to pre-incubation periods. The release of a soluble natural killer cytotoxic factor (NKCF) by peripheral blood mononuclear cells was tested by cytotoxicity assay induced in K562 cells. Natural killer cytotoxic factor release was significantly lower in SLE patients than in controls. The levels of natural killer cytotoxic factor were correlated well with NK activities, but correlated negatively with clinical activity. Pre-incubated supernatants from peripheral blood mononuclear cells with above-mentioned agents caused much higher percentage of lysis on K562 targets than that of without pre-incubation.

Adolescent↗
PubMed1992

[Observation on the effectiveness of repellent coating against mosquitoes].

The present paper reports on the effectiveness of a repellent coating for the first time. The repellent coating was made by combining DETA (N,N-diethyl-meta-toluamide) with slow-releasing reagent. With this coating employed in the laboratory against Aedes aegypti, the rate of blood-sucking was 3.9-9.5% and the rate of protection was 88.9-95.3% for 1-720 days. During 1-77 days' field trial, the RPI (Relative Population Index) was 0-8.98% in the day-time and 0.74-17.15 during the night-time against Anopheles sinensis, Culex pipiens pallens and Culex tritaeniorhynchus. It is concluded that the repellent coating is effective against mosquitoes, safe and prolongs the protection time following exposure to mosquitoes.

Aedes↗
PubMed1992

Investigation of allotypes of HLA class III (C2, BF and C4) in patients with schizophrenia.

The allotypes of HLA Class III (C2, BF and C4) in 60 patients with schizophrenia were investigated. Significantly higher frequencies of BF*F, BF*SO7 and C4A*4 in patients were found as compared with those of the normal controls. The relative risks (RR) of the three allotypes to schizophrenia were 1.81, 7.79 and 4.18 and the etiologic fraction (EF) were 0.086, 0.060 and 0.042, respectively. There were no significant changes of C2 allotypes.

Complement C2↗
PubMed1990

Genetic polymorphism of MHC class III and GLO in Chinese Yao nationality.

Yao nationality is one of the minority nationalities living mainly in South China (Guangxi Province). The purpose of this study was to provide data of MHC class III and GLO in Chinese Yao nationality and the different genetic background of Yao and Han nationality, the latter representing the major nationality in China. The genetic polymorphism of MHC class III and GLO in Chinese Yao nationality was determined. Previously the Japanese were considered to have the lowest C2*C frequencies (0.9386), but now we ascertained that the Yao have the lowest C2*C frequencies (0.9336). The data concerning gene frequencies of Yao are presented. They were also compared with the available data of Han.

China↗
PubMed1990

[Antisenility effect of ginseng-rhizome saponin].

Ginseng-Rhizome is the Rhizome of Panax ginseng and popularly named "Shenlu". The treatment group treated with the sugar-coated tablets of Ginseng-Rhizome saponin (GRS) orally for two months, one tablet (50 mg per tablet), three times a day. Through the clinical observations of 358 cases of middle and old age persons (age from 50 to 85 years old). The results showed that GRS possessed antisenility effect and marked effect on relieving the symptoms of aging, adjusting organic metabolism and improving physiological function, etc., such as promoting memory, raising the amount of white cells and improving organic immunity function. GRS both improved the function of hypophysisgonad axis and the function of adrenal cortex. It had marked efficacy in the treatment of coronary heart disease with angina pectoris and had better effect on treating concomitant atrial and ventricular prematures. The control group (123 cases, age from 50 to 85 years old) was given sugar-coated tablets of placebo (starch) for two months and then compared themselves with before. There were both no difference in clinical symptoms and experimental tests. After two years experimental researches and clinical observations, it showed that GRS tablet and Shenlu tablet both have no side effect of vomiting and also no toxic effect when they were taken for a long-term.

Aged↗
PubMed1990

Genetic polymorphisms of HLA class III and GLO1 in Chinese Yao nationality.

Yao is one of the minority nationalities located mainly in the South of China (Guang Xi province). The purpose of this study was to examine HLA class III and GLO1 in Yao nationality to identify the difference between Yao and Han. Han is the major nationality in China. Yao has the lowest C2*C frequency (0.9336) in the world. Before this study the lowest C2*C frequency known was that of the Japanese (0.9386). Gene frequencies in Yao are the following: C2*C = 0.9336, C2*B = 0.0664; BF*S = 0.9071, BF*F = 0.0929; C4A*4 = 0.0253, C4A*3 = 0.6061, C4A*2 = 0.2121, C4A*1 = 0.0152, C4A*Q0 = 0.1414; C4B*3 = 0.0051, C4B*2 = 0.0657, C4B*1 = 0.7071, C4B*92 = 0.0455, C4B*95 = 0.0253, C4B*96 = 0.0253, C4B*12 = 0.0051, C4B*Q0 = 0.1212; GLO1*1 = 0.1161, GLO1*2 = 0.8839. We have compared these data with those reported for Han.

Blood Donors↗
PubMed1990

[Sampling process in pupillary response to double pulse light stimuli].

Sampling data behavior of the pupillary control system was explored with experiments of pupillary responses to light stimuli in open loop condition (Maxwellian View). When double-pulse low intensity light stimuli with the separation longer than 0.6 seconds were applied, the pupillary responses normally resulted in a double transient contractions. When the separation between the two pulses was shorter than 0.6 s, a single transient contraction similar to those obtained for single pulse stimuli was found. The same results were obtained from different runs of experiments either in the same subject or from five different subjects. It means that a minimum period about 0.6 s is always required for the pupillary response to the second pulse light stimulus following the first response. It the reveals that dynamic behavior of the pupillary system is a discrete sampling control process. Furthermore, the pupillary responses were transient (AC) with low intensity of pulse stimuli, and were sustained (DC) with high intensity. Therefore the pupillary system control can be interpreted in terms of a dual mode control mechanism: the transient (AC) part exhibits a discrete sampling behavior, while the sustained (DC) part shows continuous feedback control.

Adult↗
PubMed1989

[Genetic polymorphism of the second component of human complement (C2) in the Han Nationality in Wuhan district of China].

A total number of 231 unrelated Chinese (Han Nationality) were investigated for C2 polymorphism by hemolytic overlay technique after polyacrylamide gel isoelectric focusing on plasmas. The following phenotype distributions were observed: C2C, 216; C2BC, 9; C2AC, 5; and C2A, 1. The gene frequencies calculated from these phenotypes were as follows: C2*A, 0.015; C2*B, 0.019; C2*C, 0.965. The C2 phenotypic frequency distributions were in agreement with those expected from Hardy-Weinberg equilibrium.

China↗