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S Z Li

Publications and source records attributed to S Z Li.

At least 37 records · Page 2Linked to original sources
PubMed2002

Observation of the decay Omega(0)(c)-->Omega(-)e(+)nu(e).

Using the CLEO detector at the Cornell Electron Storage Ring we have observed the Omega(0)(c) (css ground state) in the decay Omega(0)(c)-->Omega(-)e(+)nu(e). We find a signal of 11.4+/-3.8(stat) events. The probability that we have observed a background fluctuation is 7.6x10(-5). We measure B(Omega(0)(c)-->Omega(-)e(+)nu(e)).sigma(e(+)e(-)-->Omega(0)(c)X)=(42.2+/-14.1(stat)+/-5.7(syst)) fb and R=[Gamma(Omega(0)(c)-->Omega(-)pi(+))]/[Gamma(Omega(0)(c)-->Omega(-)enu(e))]=00.41+/-0.19(stat)+/-0.04(syst). This is the first statistically significant observation of an individual decay mode of the Omega(0)(c) in e(+)e(-) annihilation and the first example of a baryon decaying via beta emission, where no quarks from the first generation participate in the reaction.

Journal Article↗
PubMed2002

Improved measurement of /V(cb)/ using B-->D*l nu decays.

We determine the weak coupling /V(cb)/ between the b and c quarks using a sample of 3 x 10(6) BB; events in the CLEO detector at the Cornell Electron Storage Ring. We determine the yield of reconstructed B-->D*l nu; decays as a function of w, the boost of the D* in the B rest frame, and from this we obtain the differential decay rate d Gamma/dw. By extrapolating d Gamma/dw to w=1, the kinematic end point at which the D* is at rest relative to the B, we extract the product /V(cb)/F(1), where F(1) is the form factor at w=1. Combined with theoretical results for F(1) we determine /V(cb)/=0.0469+/-0.0014(stat)+/-0.0020(syst)+/-0.0018(theor).

Journal Article↗
PubMed2002

Improved measurement of Vub with inclusive semileptonic B decays.

We report a new measurement of the Cabibbo-Kobayashi-Maskawa parameter Vub made with a sample of 9.7 x 10(6) BB- events collected with the CLEO II detector. Using heavy quark theory, we combine the observed yield of leptons from semileptonic B decay in the end-point momentum interval 2.2-2.6 GeV/c with recent CLEO II data on B-->X(s)gamma to find Vub = (4.08+/-0.34+/-0.44+/-0.16+/-0.24)x10(-3), where the first two uncertainties are experimental and the last two are from theory.

Journal Article↗
PubMed2002

Search for CP violation in tau--> K(pi)nu(tau) decays.

We search and find no evidence for CP violation in tau decays into the K(pi)nu(tau) final state. We provide limits on the imaginary part of the coupling constant Lambda describing a relative contribution of the CP violating processes with respect to the standard model to be -0.172<Im(Lambda)<0.067 at 90% C.L.

Journal Article↗
PubMed2002

Observation of exclusive B --> D(*)K(*-) decays.

We report the first observation of the exclusive decays B-->D((*))K(*-), using 9.66 x 10(6) BB pairs collected at the Upsilon(4S) with the CLEO detector. We measure the following branching fractions: B(B--->D(0)K(*-)) = (6.1+/-1.6+/-1.7)x10(-4), B(B(0)-->D(+)K(*-)) = (3.7+/-1.5+/-1.0)x10(-4), B(B(0)-->D(*+)K(*-)) = (3.8+/-1.3+/-0.8)x10(-4), and B(B--->D(*0)K(*-)) = (7.7+/-2.2+/-2.6)x10(-4). The B-->D(*)K(*-) branching ratios are the averages of those corresponding to the 00 and 11 helicity states. The errors shown are statistical and systematic, respectively.

Journal Article↗
PubMed2001

[Study on time limit of ACP and sperm positive-detected in mixed spot].

OBJECTIVE: The study was carried out on time limit of ACP and sperm positive-detected in mixed spot. METHODS: 600 vaginal swabs from living body after sexual intercourse were tested by routine and three-blindness methods. RESULTS: The longest time limit of ACP which was positively detected is 255 h, average time limit is 52 h, 41.3% of those samples was ACP-detected in positive degree (++). The longest time limit of sperm positively detected is 132 h, average time limit is 29 h. The number of sperms observed in 34.3% of those samples with positive result, is from 6 to 10/HP. CONCLUSION: This study is helpful to forensic identification of sex cases.

Acid Phosphatase↗
PubMed2001

[Effect of sodium ferulate on leucocyte spontaneous activation and surface adhesion molecule expression in arteriosclerosis obliterans patients].

OBJECTIVE: To explore the effect of sodium ferulate (SF) on leucocyte spontaneous activation rate (LSAR) and the surface expression of adhesion molecule (SEAM) in patients with arteriosclerosis obliterans (ASO). METHODS: Forty-two patients with ASO were treated by SF, LSAR and SEAM in them were determined qualitatively before and after SF treatment, as well as in 36 healthy subjects for control. RESULTS: Therapeutic effect of SF in the treated 42 patients was short-term cured in 17 cases (40.5%), markedly effective in 21 (50%), effective in 2 (4.8%), ineffective in 2(4.8%), and the total effective rate being 95.2%. LSAR and SEAM in ASO patients before treatment was 14.84 +/- 7.54% and 47.94 +/- 13.48% respectively, which was obviously higher than 4.96 +/- 2.04% and 24.12 +/- 9.35% in healthy subjects (P < 0.01) respectively, but markedly reduced to 8.19 +/- 4.09% and 28.63 +/- 7.91% after SF treatment (P < 0.01). CONCLUSION: SF could not only obviously lower both LSAR and SEAM but also exert a good therapeutic effect on patients with ASO.

Adult↗
PubMed2001

[A clinical application and study of analysis system of sound spectrography].

OBJECTIVE: The phonetic features were studied for non-velopharyngeal dysfunction in postoperative patients with cleft plate. METHODS: The feature of velopharyngeal competency of 32 postoperative patients with cleft palate were analyzed with KAY-7800 sound spectrograph, compared with characteristic of 30 subjects with normal phonogram. RESULTS: There were three types of abnormal phonogram for the postoperative patients of cleft palate with velopharyngeal competence. The heavy noise was a common sight. CONCLUSION: An analytic system of sound spectrography has certain value for evaluation of phonic function in cleft palate patients.

English Abstract↗
PubMed2000

Effects of cyclosporin A on sex hormone and estrogen receptor in male rat with special reference to cyclosporin A-induced osteoporosis.

The mechanisms of high turnover bone loss induced by Cyclosporin A (CsA) are not clearly understood. Deficiencies in sex hormones result in high turnover osteoporosis, and not only androgen but also estrogen plays an important role in maintaining bone mass in men. To study whether or not there are any changes in the levels of sex hormones, aromatization, and the expression of estrogen receptors in CsA-induced osteoporosis, we treated 39 rats with vehicle, low-dose CsA (5 mg/kg) and high dose CsA (15 mg/kg) for 28 days, and measured sex hormone levels by radioimmunoassay. Aromatase activities in ROS cells and 3T3-L1 cells were determined by measuring the conversion rate of 3H-androstenedione into 3H-estrone. ER and ER mRNA were measured by competitive RT-PCR in collected marrow cells and ROS cells. The levels of free testosterone in the serum in low-dose CsA-treated rats were unchanged, but the levels were significantly decreased in those treated with high-dose CsA as previously reported. The levels of total estradiol in the serum were significantly increased in the low-dose CsA-treated group (5 mg/kg) and were comparable to levels of the control group in the high-dose CsA-treated group (15 mg/kg). CsA increased the conversion of 3H-androstenedione to 3H-estrone in ROS cells, but not in 3T3-L1 cells. Meanwhile, CsA treatment did not change the rates of ER or ER mRNA expression in ROS cells or in collected bone marrow cells. In conclusion, CsA treatment decreased the level of free testosterone in the serum, but did not decrease the level of serum estradiol by enhancing aromatization. High-turnover osteoporosis induced by clinical dosage CsA treatment may not be caused by lowering the levels of circulating estrogen or by decreasing the expression of estrogen receptors.

3T3 Cells↗
PubMed2000

[Clinical significance of plasma PGE2 levels in pre- and post-operative patients with laryngeal carcinoma].

OBJECTIVE: To study the clinical significance of PGE2 Levels in patients with laryngeal carcinoma. METHOD: Radioimmunoassay was used to evaluate plasma PGE2 levels in 35 patients with laryngeal carcinoma. RESULT: The plasma PGE2 levels in patients with laryngeal carcinoma were significant higher than that of normal subjects (P < 0.05), but there was no correlation with the stage of laryngeal carcinoma (P > 0.05). The plasma PGE2 levels of postoperative patients with laryngeal carcinoma were significant lower than that of preoperative patients (P < 0.05). After operation, the plasma PGE2 levels of recurrent patients were significant higher than that in patients with no recurrence (P < 0.01). CONCLUSION: The determination of PGE2 levels in patient plasma may help the diagnosis and prognostic judgment of laryngeal carcinoma.

Carcinoma, Squamous Cell↗
PubMed1999

Type I beta-turn conformation is important for biological activity of the melanocyte-stimulating hormone analogues.

In order to define which structure of alpha-melanocyte-stimulating hormone (MSH) analogues plays a critical role for ligand-receptor interaction and selectivity, we analysed receptor-binding and cAMP-generating activity in Chinese hamster ovary cell lines stably transfected with rMC3R and hMC4R, as well as the NMR structures of chemically synthesized alpha-MSH analogues. Compared with [Ahx4]alpha-MSH, the linear MTII designated as alpha-MSH-ND revealed a preference for the MC4R, whereas its IC50 and EC50 values were comparable to those of MTII reported previously. Truncation of Ahx4 and Asp5 of alpha-MSH-ND remarkably decreased the receptor-binding and cAMP-generating activity. Meanwhile, maximum cAMP-generating activity was observed at a higher concentration (10(-5) M) of alpha-MSH-ND(6-10), and MC4R preference was changed into MC3R preference. In contrast, [Gln6]alpha-MSH-ND(6-10) lost its cAMP-generating activity almost completely, even though it bound to both receptors. Whereas the solution conformation of alpha-MSH-ND revealed a stable type I beta-turn structure, [Gln6]alpha-MSH-ND(6-10) revealed a tight gamma-turn composed of Gln6-D-Phe7-Arg8. Replacement of the His6 residue of alpha-MSH-ND by Gln, Asn, Arg or Lys decreased not only the receptor binding, but also the cAMP-generating activity in both the MC3R and the MC4R. The structure of [Gln6]alpha-MSH-ND exhibited a stable type I' beta-turn comprising Asp5, Gln6, D-Phe7 and Arg8. [Lys6]alpha-MSH-ND showed a greatly reduced binding affinity and cAMP-generating activity with the loss of MC4R selectivity. In NMR studies, [Lys6]alpha-MSH-ND also demonstrated a gamma-turn conformation around Lys6-DPhe7-Arg8. From the above results, we conclude that a type I beta-turn conformation comprising the residues Asp5-His6-(D-Phe7)-Arg8 was important for receptor binding and activation, as well as the selectivity of MSH analogues.

Animals↗
PubMed1997

Membrane formation and cellular response on the surface of lenses implanted in rabbit eyes.

PURPOSE: To study the pathogenesis of membrane formation and cellular response on the surface of posterior chamber intraocular lenses (IOLs) implanted in rabbits. SETTING: Department of Histology and Embryology, Pathology, Ophthalmology. The First Military Medical University, Guangzhou, P.R. China. METHODS: Thirty rabbits had extracapsular lens extraction and posterior chamber IOL implantation. The IOLs were removed 4, 7, 15, 30, and 90 days postoperatively. Membrane formation and cellular response on IOL surfaces were evaluated using light (n = 25), transmission (n = 5), and scanning electron (n = 5) microscopy. RESULTS: On 30 IOLs, the incidence of cellular adhesion was 100%. Cellular components comprised macrophages, fibroblast-like cells, epithelioid cells, giant cells, ultralarge giant cells, and lymphocytes. A thin, proteinaceous film was also seen on the surface of the IOLs. The membrane of the IOL surface comprised fibrin, collagen fibrils, macrophages, fibroblast-like cells, giant cells, and fibroblasts. CONCLUSION: The findings of this study might apply to humans because cellular elements and membranes have been reported in humans.

Animals↗
PubMed1994

The development changes and correlations of some blood hormone levels and immune indexes during the postnatal period in neonatal calves.

The developmental changes and correlations of some hormone levels and immune parameters in six spontaneously delivered Holstein calves with a birth weight of 40-50 kg were studied for a postnatal period of 1-15 days after birth. The mean levels of insulin (I), glucagon (Gc), cortisol (C) and growth hormone (GH) before feeding on day 1 were 9.68 +/- 3.27 muu/ml, 685.39 +/- 95.42 pg/ml, 14.27 +/- 5.58 micrograms/dl and 0.85 +/- 0.10 ng/ml respectively. I and GH increased on day 2 and then decreased to a steady level. Gc and C fell fluctuantly within week 1 and remained at a stable level after then. WBC, neutrophil percentage, B-lymphocyte percentage, albumin percentage decreased with day of age in 1st week and lymphocyte percentage, T-lymphocyte percentage, T-G (total globulin) percentage and gamma-G percentage increased with day of age in 1st week and then reached a steady level. The correlations between some hormone levels and immune parameters indicated that C and Gc have significantly negative correlations with gamma-G (%), T-G (%) and T-lymphocyte (%) respectively. WBC is positively correlated to C and Gc significantly. The correlations of I and GH with some immune parameters have no significance.

Animals↗
PubMed1994

[Study on the collagen of the different region of disc and different sigmental disc].

With the method of the collagen decomposition producting special hyoroxyprolines (HYP), the collagens of the different region of discs and different segmental discs were studied. The results were as follow: The fibrous annulus had a higher collagen content than did the nucleus pulposus (P < 0.001). In fibrous annulus, the inner region had a lower collagen content was found at the postolateral part of the fibrous annulus (P < 0.05), especially at the poster-lateral inner zone (P < 0.001). The local low-collagen content at the particular location may be one of the factors, which was clinically susceptible to a disc herniation at the part. An increasing graduation of collagen content was found from thoracic disc12 to lumbar disc 5. But, there was no statistically significant difference (P > 0.05).

Adult↗
PubMed1994

[Cataract extraction and intraocular lens implantation in patients with uveitis].

Thirty two patients with uveitis had a posterior chamber intraocular lens implantation after extracapsular cataract extraction. After a mean follow-up period of 5.4 months (range 3 to 29 months), the corrected visual acuity in 93.7% of the patients reached to 0.5 or better. Postoperative complications included posterior capsule opacification and iris posterior synechiae. The results suggest that careful selection of candidates for IOL implantation be crucial for successful cataract surgery in uveitis patients.

Adolescent↗