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1.
Acoustic wave propagation in piezoelectric crystals of classes?43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe4 (43m) of the Chalcogenide family and the crystal Bi12TiO20 (23) possess strong piezoelectric effect. Because the surface Bleustein-Gulyaev waves cannot exist in piezoelectric cubic crystals, it was concluded that new solutions for shear-horizontal surface acoustic waves (SH-SAWs) are found in the monocrystals using different electrical boundary conditions such as electri- cally “short” and “open” free-surfaces for the unique [101] direction of wave propagation. For the crystal Tl3TaSe4 with coefficient of electromechanical coupling (CEMC) Ke2=e2/(C×g)～1/3, the phase velocity Vph for the new SH-SAWs can be calculated with the following formula: Vph=(Va Vt)/2, where Vt is the speed of bulk SH-wave, Vt=Vt4(1 Ke2)1/2, Va=aKVt4, aK=2[Ke(1 Ke2)1/2-Ke2]1/2, and Vt4=(C44/ρ)1/2. It was found that the CEMC K2 evaluation for Tl3TaSe4 gave the value of K2=2(Vf–Vm)/Vf～0.047 (～4.7%), where Vf～848 m/s and Vm~828 m/s are the new-SAW velocities for the free and metallized surfaces, respectively. This high value of K2(Tl3TaSe4) is significantly greater than K2(Tl3VS4)～3% and about five times that of K2(Bi12TiO20).  相似文献   

2.
In order to comply with the requirements for a drug listed in China, the study was developed to compare the pharmacokinetics and relative bioavailability of two different enteric formulations of omeprazole (OPZ) in healthy Chinese subjects. A total of 32 volunteers participated in the study. Plasma concentrations were analyzed by nonstereospecific liquid chromatography/tandem mass spectrometric (LC-MS/MS) method. After administration of a single 40-mg dose of the two OPZ formulations, the comparative bioavailability was assessed by calculating individual AUC0−t (the area under the concentration-time curve from time zero to the last measurable concentration), AUC0−∞ (the area under the concentration-time curve extrapolated to infinity), C max (the maximum observed concentration), and T peak (the time to C max) values of OPZ, 5-hydroxyomeprazole (OH-OPZ), and omeprazole sulfone (OPZ-SFN), respectively. The 90% confidence intervals (CIs) of AUC0−t , AUC0−∞, and C max were 85.4%–99.0%/88.8%–98.6%/87.6%–99.4%, 85.5%–99.2%/89.0%–98.6%/88.5%–101.3%, and 72.3%–87.6%/79.6%–91.1%/88.4%–99.1% for OPZ/OH-OPZ/OPZ-SFN, respectively, and T peak values did not differ significantly. In this study, the test formulation of OPZ in fasting healthy Chinese male volunteers met the Chinese bioequivalance standard to the reference formulation based on AUC, C max, and T peak.  相似文献   

3.
INTRODUCTION Throughout this paper, we shall work with a filtered complete probability space (?,F,(Ft),P) sat-isfying the usual conditions. Let B=(Bt)t≥0 be a stan-dard Brownian motion with B0=0. Denote by ú the set of all non-negative real numbers. Recall that a diffusion process X starting at x≥0 is called the square of a Bessel process of dimension δ>0 if d X t = δd t 2 | X t |d Bt , X 0= x, (1) Clearly, this equation has a unique non-negative strong solution X, i.e., …  相似文献   

4.
To assess the influence of cyclosporin A (CsA) and tacrolimus (FK506) on mycophenolic acid (MPA) and correlation analysis of the pharmacokinetic parameters and patient characteristics, clinical outcome in Chinese kidney transplant recipients, the pharmacokinetics of 1000 mg mycophenolate mofetil (MMF) twice daily was measured by high-performance liquid chromatography (HPLC). PKS (Pharmaceutical Kinctics Software) 1.0.2 software package was used for the calculation of pharmacokinetic parameters. The meanC max,t max, and AUC(0–12) were (21.88±10.52) μg/ml, (1.20±0.95) h, and (52.546±13.215) μg·h/ml, respectively. The level of AUC(0–12) in the FK506 group was significantly higher than that in the CsA group. MPA appeared not to be affected by renal function. MPA AUC(0–12) showed statistically significant difference according to the patient's gender. Project (No. 20040462) supported by the Foundation of Education Bureau of Zhejiang Province, China  相似文献   

5.
In this paper, the obtained experimental results concerning creation of bulk elementary excitations (BEEs) in iso-topically pure liquid 4He at low temperatures ~60 mK are discussed. Positive rotons’ (R -rotons) creation by a pulsed heater was studied. Signals were recorded for the following quantum processes: quantum evaporation of 4He-atoms from the free liq- uid-helium surface by the BEEs of the liquid helium-II, and BEEs reflection from the free surface back into the bulk liquid. Typical signals are shown, and ratios of signal amplitudes are evaluated. For long heater pulses from 5 to 10 μs, appearance of the second atomic cloud consisting of evaporated 4He-atoms was observed in addition to the first atomic cloud. It is thought that the first atomic cloud of the evaporated helium atoms consists of very fast 4He-atoms with energies ~35 K evaporated by positive rotons with the special energies ~17 K (~2ER~2×8.6 K with ER representing the roton minimum energy) corresponding to the third non-dispersive Zakharenko wave. The second cloud of slower 4He-atoms was created by surface elementary excitations (SEEs or ripplons) possessing the special energies ~7.15 K representing the binding energy. It was assumed that such SEEs can be created by phonons incoming to the liquid surface with special energies ~6.2 K corresponding to the first non-dispersive Zakharenko wave, which can interact at the liquid surface with the same phonons already reflected from the surface for long heater pulses. Also, some pulsed-heater characteristics were studied in order to better understand the features of such heaters in low temperature experi- ments.  相似文献   

6.
１ＩｎｔｒｏｄｕｃｔｉｏｎＤｉｆｅｒｅｎｔｉａｌｅｑｕａｔｉｏｎｓｗｉｔｈｔｕｒｎｉｎｇｐｏｉｎｔｓｅｘｉｓｔｗｉｄｅｌｙｉｎｍａｎｙｐｒｏｂｌｅｍｓｏｆｍａｔｈｅｍａｔｉｃｓｐｈｙｓｉｃｓ,ｓｏｔｈｅｓｅｐｒｏｂｌｅｍｓａｒｅｖｅｒｙｉｍｐｏｒｔａ...  相似文献   

7.
INTRODUCTION Nitrogen oxide (NOx) is one of the main air pol- lutants found in the flue gases from chemical and power plants belching acid rain and photochemical smog. Over 90 percent of all man-made nitrogen ox- ides that enter our atmosphere are produced by the combustion of various fuels. Compared with the ad- vanced stage of SO2 gas removal technologies devel- opment, the removal of NOx gases is still in the initial stages of development as roughly 90 to 95 percent of NOx emitted i…  相似文献   

8.
Objective  This study is to determine the effect of the natural product parthenolide, a sesquiterpene lactone isolated from extracts of the herb Tanacetum parthenium, on the proliferation of vascular smooth muscle cells (VSMCs). Methods  Rat aortic VSMCs were isolated and cultured in vitro, and treated with different concentrations of parthenolide (10, 20 and 30 μmol/L). [3H]thymidine incorporation was used as an index of cell proliferation. Cell cycle progression and distribution were determined by flow cytometric analysis. Furthermore, the expression of several regulatory proteins relevant to VSMC proliferation including IκBα, cyclooxygenase-2 (Cox-2), p21, and p27 was examined to investigate the potential molecular mechanism. Results  Treatment with parthenolide significantly decreased the [3H]thymidine incorporation into DNA by 30%∼56% relative to control values in a dose-dependent manner (P<0.05). Addition of parthenolide also increased cell population at G0/G1 phase by 19.2%∼65.7% (P<0.05) and decreased cell population at S phase by 50.7%∼84.8% (P<0.05), which is consistent with its stimulatory effects on p21 and p27. In addition, parthenolide also increased IκBα expression and reduced Cox-2 expression in a time-dependent manner. Conclusion  Our results show that parthenolide significantly inhibits the VSMC proliferation by inducing G0/G1 cell cycle arrest. IκBα and Cox-2 are likely involved in such inhibitory effect of parthenolide on VSMC proliferation. These findings warrant further investigation on potential therapeutic implications of parthenolide on VSMC proliferation in vivo. Project (No. 491020-W50315) supported by the Foundation of the Health Bureau of Zhejiang, China  相似文献   

9.
SO4^2- / TiO2-La2O3, a novel solid superacid, was prepared and its catalytic activities at different synthetic conditions are discussed with esterification of n-butanoic acid and n-butyl alcohol as probing reaction. The optimum conditions have also been found, mole ratio of n（La^3＋）：n（Ti^4＋） is 1：34, the soaked consistency of H2SO4 is 0.8 tool/L, the soaked time of HESO4 is 24 h, the calcining temperature is 480 ℃, the calcining time is 3 h. Then it was applied in the catalytic synthesis often important ketals and acetals as catalyst and revealed high catalytic activity. Under these conditions on which the molar ratio of aldehyde/ketone to glycol is l： 1.5, the mass ratio of the catalyst used in the reactants is 0.5%, and the reaction time is 1.0 h, the yields of ketals and acetals can reach 41.4%-95.8%.  相似文献   

10.
Modified 1-ethyl-3-(3-dimethylaminopropy) carbodiimide (EDC) method was employed to synthesize the artificial antigen of enrofloxacin (ENR), and New Zealand rabbits were used to produce anti-ENR polyclonal antibody (pAb). Based on the checkerboard titration, an indirect competitive enzyme-linked immunosorbent assay (ELISA) standard curve was established. This assay was sensitive and had a linear range from 0.6 to 148.0 μg/kg (R 2=0.9567), with the half maximal inhibitory concentration (IC50) and limit of detection (LOD) values of 9.4 μg/kg and 0.2 μg/kg, respectively. Of all the competitive analogues, the produced pAb exhibited a high cross-reactivity to ciprofloxacin (CIP) (87%), the main metabolite of ENR in tissues. After optimization, the matrix effects can be ignored using a 10-fold dilution in beef and 20-fold dilution in pork. The overall recoveries and coefficients of variation (CVs) were in the ranges of 86%–109% and 6.8%–13.1%, respectively. It can be concluded that the established ELISA method is suitable for simultaneous detection of ENR and CIP in animal tissues.  相似文献   

11.
Let K be a closed convex subset of a real reflexive Banach space E, T：K→K be a nonexpansive mapping, and f：K→K be a fixed weakly contractive （may not be contractive） mapping. Then for any t∈（0, 1）, let x1∈K be the unique fixed point of the weak contraction x1→tf（x）＋（1-t）Tx. If T has a fixed point and E admits a weakly sequentially continuous duality mapping from E to E^＊, then it is shown that {xt} converges to a fixed point of T as t→0. The results presented here improve and generalize the corresponding results in （Xu, 2004）.  相似文献   

12.
1　Introduction　Ahugeamountofliteratureexistsonthestudyofi dentifyingtracemetalionsbymeansofspectropho tometry[1 3] ,fluorimetry[4 6 ] aswellas polarogra phy[7 9] ,whichhaveactiononlocatingtheendpointoftheindicatingreaction .Howeverbothspectropho tometryandfluorimetryareeasytobeinterferedbycolororprecipitation ,whilepolarographyhasanissueofmercurypollution .Thecatalyzingkineticanalysishasthecharacteristicsofhighsensitivityandspeedi ness.Oscillographicpotentiometryisasimpleintu itionisticanal…  相似文献   

13.
Pakistani wheat varieties are grown over a wide agro-climatic range and as such are anticipated to exhibit yield and quality differences. It is therefore necessary to investigate the nutritional status of wheat varieties in terms of biochemical and physiochemical characteristics available for food and nutritional purposes in Pakistan. The result shows that wheat grains of different varieties contain a net protein level of 9.15%～10.27%, 2.15%～2.55% total fats, 1.72%～1.85% dietary fibers,77.65×10^-6～84.25×10^-6 of potassium and 7.70× 10 6～35.90× 10^-6 of sodium ions concentration, 0.24× 10^-6～0.84× 10^-6 of phosphorus, 1.44%～2.10% ash, 31.108～43.602 g of thousand grain mass （TGM） and 8.38%～9.67% moisture contents. This study is significant in providing an opportunity to explore the available wheat varieties and to further improve their nutritional excellence and also essential for setting nutritional regulations for domestic and export purposes.  相似文献   

14.
Radiation therapy has been widely applied in cancer treatment. However, it often causes thrombocytopenia (deficiency of white blood cells) as an adverse effect. Recombinant human interleukin-6 (rhIL-6) has been found to be a very effective way against this thrombocytopenia, but IL-6 has low stability in blood, which reduces its efficacy. To increases the stability and half-life of rhIL-6, it was modified by polyethylene glycol (PEG). The pharmacokinetics and the tissue distribution of PEG-rhIL-6 labeled with 125I were examined after subcutaneous injection in rats. The pharmacokinetic pattern of PEG-rhIL-6 was defined with linear-kinetics, and we fitted a one-compartment model with half-lives of 10.44–11.37 h (absorption, t 1/2K a) and 19.77–21.53 h (elimination, t 1/2Ke), and peak concentrations at 20.51–21.96 h (t peak) in rats. Half-lives and t peak of PEG-rhIL-6 were longer than those of rhIL-6 previously reported. In the present study, for deposition of PEG-rhIL-6 in rats, the tissue distribution examination showed that blood was the major organ involved, rather than liver. However, as to the elimination of PEG-rhIL-6, the major organ was the kidney. The excretion fraction of the injection dose recovered from urine was 23.32% at 192 h after subcutaneous administration. Less than 6% of PEG-rhIL-6 was eliminated via the feces at 192 h. These results indicate that PEG-rhIL-6 is a good candidate drug formulation for patients with cancer.  相似文献   

15.
1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　Ｔｈｅｆｕｎｄａｍｅｎｔａｌｐｈｙｓｉｃａｌｍｅｔａｌｌｕｒｇｙｏｆｔｈｅｒｍｏｍｅｃｈａｎｉｃａｌｐｒｏｃｅｓｓｉｎｇ(ＴＭＰ)ｈａｓｂｅｃｏｍｅｍｕｃｈｂｅｔｔｅｒｕｎｄｅｒｓｔｏｏｄｏｖｅｒｔｈｅｌａｓｔｔｗｏｄｅｃａｄｅｓ[1～8].ＩｔｉｓｗｅｌｌｃｏｍｍｏｎｌｙｒｅｃｏｇｎｉｚｅｄｔｈａｔｔｈｅｍｉｎｕｔｅａｄｄｉｔｉｏｎｏｆｓｔｒｏｎｇｃａｒｂｏｎｉｔｒｉｄｅｏｒｎｉｔｒｉｄｅｆｏｒｍｉｎｇｅｌｅｍｅｎｔｓｓｕｃｈａｓＮｂ,ＴｉａｎｄＶｔａｋｅｓｖｅｒｙｉｍｐ…  相似文献   

16.
1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　Ｉｎｔｈｅｐａｓｔｄｅｃａｄｅｏｒｓｏ ,ｔｈｅｅｘｉｓｔｅｎｃｅｏｆｇｌｏｂａｌａｔ ｔｒａｃｔｏｒｓａｎｄｔｈｅｅｓｔｉｍａｔｅｓｏｆｔｈｅｉｒＨａｕｓｄｏｒｆｆａｎｄｆｒａｃｔａｌｄｉｍｅｎｓｉｏｎｓｈａｖｅｂｅｅｎｉｎｖｅｓｔｉｇａｔｅｄｆｏｒｎｕｍｅｒｏｕｓｄｉｓｓｉｐａ ｔｉｖｅｎｏｎｌｉｎｅａｒｐａｒｔｉａｌｄｉｆｆｅｒｅｎｔｉａｌｅｑｕａｔｉｏｎｓｗｈｉｃｈａｒｅａｕ ｔｏｎｏｍｏｕｓ[1～ 4 ].Ｔｈｅｎｏｎ ａｕｔｏｎｏｍｏｕｓｉｎｆｉｎｉｔｅ ｄｙｎａｍｉ…  相似文献   

17.
Infrared （IR） absorption spectra and X-ray powder diffraction （XRD） patterrns of sexpenfine cat＇s eye from Sichuan Province have been investigated, and infrared absorption bands of the serpentine have been assigned in this paper. The results indicate that the bands near 3 600 - 3 700 cm^-1 belong to the stretching absorption band VOH, the bands in 948 - 1 100 cm^-1 axe assigned to the stretching vibraling band Usvo, and the bands at 600 570 and 440 cm^-1 respectively belong to the bending vibration band VOH, δMg-O and δSi-O. The serpentine cat＇ s eye includes two types： chrysotile and antigorite. Chrysotile has a sharp and intensive band at 3 688 cm^-1 and a weak band at 3 643 cm^-1 , while antigorite has only one intensive band in the region. At vibration band VSi-O, chrysotile and antigorite have a similar feature at 1 071 cm^-1, but the band at 980 cm^-1 in anfigorite has been split into two bands in chrysotile - a strong one at 1 027 cm^-1 and a weak one at 949 cm^-1. In addition, antigorite has a characteristic bending vibrating band δMg-O at 570 cm^-1. Based on the analysis of the feature of crystal structure, their IR differences axe well explained.  相似文献   

18.
Objective: To investigate the influence of lead exposure on the immune function of lymphocytes and erythrocytes in preschool children. Materials and methods: A group of 217 children three to six years of age from a rural area were given a thorough physical examination and the concentration of lead in blood samples taken from each subject was determined. The indices of lymphocyte immunity (CD 3CD 4, CD 3CD 8, CD 4CD 8, CD-3CD 19) and erythrocyte immunity (RBC-C3b, RBC-IC, RFER, RFIR, CD35 and its average fluorescence intensity) of 40 children with blood lead levels above 0.483 μmol/L were measured and compared with a control group. Results: The blood lead levels of the 217 children ranged from 0.11 μmol/L to 2.11 μmol/L. The CD 3CD 4and CD 4CD 8 cells were lower (P＜0.01) and the CD 3CD 8 cells were higher in the lead-poisoned subjects than those in the control group (P＜0.05). CD 3 and CD-3CD 19 did not show significant differences. Although the RBC-C3b rosette forming rate was lower and the RBC-IC rosette forming rate was higher in the lead-poisoned group, this difference could not be shown to be statistically significant (P＞0.05). RFIR was found to be lower in the lead-poisoned group (P＜0.01). Compared with the control group, the positive rate of CD35 was not found to be significantly different in a group of 25 lead-poisoned children (P＞0.05), while the average fluorescence intensity was lower in the lead-poisoned group (P＜0.05). Conclusion: Lead exposure can result in impaired immune function of T lymphocytes and erythrocytes in preschool children.  相似文献   

19.
BaFe12O19 powders with nanocrystaUine sizes were produced by sol-gel auto-combustion method. The precursors were prepared under the molar ratios of citric acid to the metal nitrate of 0.5, 1.0 and 1.5. Appropriate ethylene diamine （C2H8N2） was added in order to adjust pH of 7. The ions distribution of citric acid at different pH explains the effect of citric acid in the starting solution. The XRD patterns of the as-burnt powders and annealing powders show different phases for different citric acid content. In addition, the lattice constants （a, c） derived from X-ray diffraction pattern were changed from 0.58881 nm to 0.58997 nm and 2.32057 nm to 2.32296 nm respectively. The data from VSM indicated that the powder with high citric acid content took on good magnetic properties. Pure single BaFe12O19 of the specific maximum magnetization M（1 T）≈ 49.73 Am^2/kg, the specific remanent magnetization Mr ≈ 30.77 Am^2/kg and the coercive force He≈ 467 kA/m was produced when the molar ratios of citric acid to the metal nitrate was 1.5.  相似文献   

20.
It is of great importance to investigate an effective and reliable medication against chronic renal failure (CRF)-related erectile dysfunction (ED), which aims to improve patients’ life qualities. The concentrations of cyclic guanosine monophosphate (cGMP) in the corpus cavernosal smooth muscle of both CRF and control rabbits were measured. The effects of various concentrations of tadalafil, papaverine, and sodium nitroprusside on the relaxation responses of corpus cavernosal smooth muscle pre-contracted with phenylephrine in CRF rabbits were observed. There was significant difference in the concentration of cGMP between CRF and control rabbits (P<0.01). Tadalafil had the greatest impacts on CRF rabbits when given the same concentration of papaverine or sodium nitroprusside and particularly significant differences were identified under the concentration levels of 10−5 and 10−4 mol/L (P<0.01). The results suggest that the cGMP concentrations of the corpus cavernosum had been greatly reduced in CRF rabbits compared with control rabbits and that tadalafil may be an ideal medication for use in the treatment of CRF-related ED.  相似文献   

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