PubMed Health⌕ Search

Biomedical subjects

J Kou

Publications and source records attributed to J Kou.

10 recordsLinked to original sources
PubMed2004

Double photoionization of C(60) and C(70) in the valence region.

Photoion yields from gaseous fullerenes, C(60) and C(70), for production of singly and doubly charged ions are measured by mass spectrometry combined with tunable synchrotron radiation at hnu=25-150 eV. Since the signal of triply or highly charged ions is very weak, the total photoionization yield curve can be estimated from the sum of the yields of the singly and doubly charged ions. A distinct feature appears in the resultant curve of C(60) which is absent in the calculated total photoabsorption cross section previously reported. This difference is attributed to C(60) (2+) ions chiefly produced by spectator Auger ionization of the shape resonance states followed by tunneling of the trapped electron or by cascade Auger ionization. Ratios between the yields of doubly and singly charged ions for C(60) and C(70) are larger than unity at hnu>50 eV. These ratios are quite different from those reported in the experiments using electron impact ionization.

Journal Article↗
PubMed2004

Lot consistency as an equivalence problem.

One requirement for licensure of a vaccine in the United States is demonstration by the manufacturer of consistently produced lots of vaccine. Demonstration of consistency of manufacturing can be viewed as a multigroup equivalence problem. The standard statistical procedures for evaluating equivalence assume normally distributed data and define equivalence margins with respect to group means. As an alternative approach, we define a measure of the similarity among group distributions and their nonparametric estimators. Through computer simulations we explore the statistical properties of an equivalence test based on this estimator and compare them to the standard methods. Preliminary work suggests that a test of similarity can be useful in demonstrating equivalence when distributions are not normal or when there are differences in scale or shape. It appears to detect departures from equivalence that are not reflected by differences among group means.

Models, Theoretical↗
PubMed2002

Risk factors for spinal epidural hematoma after spinal surgery.

STUDY DESIGN: A case-control retrospective analysis comparing patients who developed a postoperative spinal epidural hematoma with patients who did not develop this complication. OBJECTIVES: To identify risk factors for the development of an epidural hematoma following spinal surgery. SUMMARY OF BACKGROUND DATA: Neurologic deterioration following spinal surgery is a rare but devastating complication. Epidural hematomas should be suspected in the patient who demonstrates a new postoperative neurologic deficit. The risk factors that predispose a patient to a postoperative spinal epidural hematoma have not been identified. METHODS: Patients who underwent spinal surgery at a single institution over a 10-year period were retrospectively reviewed. Twelve patients who demonstrated neurologic deterioration after surgery and required surgical decompression because of an epidural hematoma were identified. All cases involved lumber laminectomies. A total of 404 consecutive patients that underwent lumbar decompression and did not develop an epidural hematoma formed the control group. Factors postulated to increase the risk of postoperative spinal epidural hematoma were compared between the two groups using logistic regression. RESULTS: Multilevel procedures (P = 0.037) and the presence of a preoperative coagulopathy (P < 0.001) were significant risk factors. Age, body mass index, perioperative durotomies, and postoperative drains were not statistically significant risk factors. CONCLUSIONS: Patients who require multilevel lumbar procedures and/or have a preoperative coagulopathy are at a significantly higher risk for developing a postoperative epidural hematoma.

Blood Coagulation Disorders↗
PubMed1998

Study on the transmission threshold value of bancroftian filariasis.

OBJECTIVE: To elucidate the transmission dynamic and epidemic trend of bancroftian filariasis occurred under the condition with no control measure taken 5 years after elimination of filariasis. METHODS: A 10-year longitudinal observation (from 1984 to 1994) was made in Huayuan Village in Shengli Township of Tancheng County, which used to be a high bancroftian filariasis-endemic area in southern part of Shandong Province. RESULTS: The microfilarial rate decreased from 0.56% before the study to 0.12% after the study and 8 out of the 9 previous microfilaria-positive cases became negative gradually. During the study period, 6 new microfilaremia cases were detected, 5 of which became negative naturally within 3 to 4 years. Eighty-eight point eight nine per cent of the detected patients with microfilaremia converted into IgG4-negative after 10 years. The natural infective rate of vectors decreased year by year and became zero by the tenth year of the study, the annual transmission potency decreased also from 3.47 to zero by the tenth year. CONCLUSIONS: It showed that under the local natural environment the biting rate representing the vector density which was obtained by capture method was from 24.1 to 52.5 person/night among the residents who did not use mosquito nets, and 13.5 to 21 person/night among the residents who used mosquito nets. The microfilarial rate of 0.56% in population with the average microfilarial density of 6.6 to 20.7 capita/60 microliters ear blood of residual microfilaria-positive patients might be considered as the terminal threshold of transmission.

Animals↗
PubMed1997

[Effects of yizhi pills on memory, superoxide dismutase and malondialdehyde of brain and immunity in mice].

Passive avoidance tests have shown that Yizhi Pills (YZ) markedly improve the memory of normal mice at a dose of 100 mg/kg after oral administration for fifteen days, and significantly reverse the scopolamine, NaNO2 and EtOH-induced disruptions of memory retention in mice at doses of 100, 200, 500 mg/kg after oral administration for five days. In aged mice induced by D-galactose, YZ also significantly improve the impaired memory, increase the activity of SOD and decrease the content of MDA in brain. All these effects were observed at doses of 200, 500 mg/kg after oral administration for forty-one days. YZ significantly promote blood carbon particle clearance, enhance hemolysin antibody in immunodepressed mice induced by cyclophosphamide, and increase earswelling in immunodepressed mice induced by prednisolonum.

Animals↗
PubMed1997

[Pharmacological study on the compatibility of cortex Cinnamomi with Halloysitum Rubrum].

The decoction of Cortex Cinnamomi (CC, 1 g/kg p.o.) and Halloysitum Rubrum (HR, 3 g/kg p.o.) or the combination of the two drugs (4 g/kg p.o., CC 1 g/kg, HR 3 g/kg) could antagonize the diarrhea caused by p.o. water ex tract of Radix et Rhizoma Rhei in mice; and inhibit the platelet aggregation induced by ADP in vitro. Meanwhile, the effect of the combination of the two drugs was not different from that of each single one. In addition, CC was able to inhibit the spontaneous movement of intestine in situ and showed an analgesic effect (hot-plate method) in mice; HR was ineffective in these aspects and did not reduce the effect of CC. CC(20 g/kg p.o., i.p. or i.v.) exhibited very strong toxicity in mice, while HR(60 g/kg p.o., i.p. or i.v.) was nontoxic. When the two drugs were used together, the toxicity was markedly reduced.

Aluminum Silicates↗
PubMed1996

Teaching safety: evaluation of a children's village in Maryland.

OBJECTIVES: The purpose of this study was to evaluate Children's Village, a life safety education facility for children. SETTING: The study took place in Washington County, Maryland, a rural county. METHODS: Eight elementary schools with 20 second grade classrooms (410 students aged 7 and 8) were selected to participate. Using a quasiexperimental design, tests were administered to two cohorts of children before (pretest) and after (post-test) they attended the Children's Village during 1993-4. Parent and teacher surveys were also completed after the program. RESULTS: Among children who attended in December 1993-January 1994, there was a significant improvement in average test scores between the pretest (58% correct) and post-test (78%). Among children who attended in April 1994, there also was a significant improvement in test scores between pretest (74%) and post-test (85%). Among parents, 70% reported that their child learned a great deal at Children's Village and 33% reported having made changes in their home as a result. The parent survey also revealed that 25% of children and 35% of adults did not always wear their seat belts, and 74% of children did not always wear bicycle helmets. Teachers' responses to the program were generally positive. CONCLUSIONS: Children's Village brought together an extensive network of community leaders, parents, and teachers dedicated to safety education of children. The curriculum had a positive impact on children's knowledge and, to a lesser extent, on parents' safety practices. Program impact could be enhanced by more emphasis on automobile restraints and helmets (behaviors that parents reported were not consistently practiced) and by expanding the village services to parents as well as children. Others considering creating similar programs need to identify community leaders willing to commit the time, effort, and resources required to develop and sustain such programs.

Accident Prevention↗
PubMed1995

Effect of ibudilast on ciliary activity of human paranasal sinus mucosa in vitro.

The effect of ibudilast (CAS 50847-11-5, 3-isobutyryl-2-isopropylpyrazolo[1,5-a]pyridine, KC-404), an anti-asthmatic drug, on ciliary beat frequency (CBF) of human paranasal sinus mucosa was examined in vitro. Ciliary activation was observed after a 10-min exposure to 4.6 x 10(-6) mol/l ibudilast. Ibudilast dose-dependently increase CBF at the concentrations ranging from 4.6 x 10(-7) mol/l to 4.6 x 10(-5) mol/l. Propranolol inhibited ciliary activity induced by ibudilast; however, neither indometacin nor verapamil affected the activation of ibudilast on CBF. Platelet activating factor (PAF) and Leukotriene D4 (LTD4) are chemical mediators inducing mucosal dysfunction and damage. Ibudilast prevented ciliary inhibition induced by PAF and LTD4. These findings indicated that ibudilast activates CBF and inhibits the effect of PAF and LTD4 on ciliated cells, and consequently improves the pathogenesis of allergic disorders such as the inhibited mucociliary transport system and airway hyperresponsiveness.

Bronchodilator Agents↗
PubMed1980

Analysis of models for determining intestinal wall permeabilities.

In determining intestinal wall permeabilities, several mass transport models may be applied to analyze the results from external perfusion experiments. The appropriateness of any given model depends on the applicability of the model assumptions to the experimental system. This report compares several mass transport models with respect to their assumptions and applicability to a particular experimental design. The models are shown to differ in their assumptions regarding convection and diffusion in the perfusing fluid. However, since the wall permeability is an unknown parameter in each model and is estimated from the data, all of the models fit the mass transfer results reasonably well, despite fundamentally different assumptions. However, the determined permeabilities differ. Residence time distribution analysis of the experimental system is more sensitive to the model assumptions. It is shown that, in a particular experimental system, laminar flow in a cylindrical tube is the most appropriate model. The model also has the advantage of implicitly accounting for the convection-diffusion problem in the perfusing fluid. Hence, the diffusion layer thickness is not estimated from the data. With the hydrodynamics defined, the relative permeabilities resulting from the application of the several models to the data can be interpreted. The wall permeability determined in the suggested manner provides an estimate of the limiting assistance under perfect mixing conditions.

Animals↗