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31.
OBJECTIVE: To study the effects of thevetoside (TS), a cardiac glycoside, and an inhibitor of Na+, K(+)-ATPase, on tumor cells cultured in vitro. METHODS: The cytotoxic effects of TS on tumor cells were determined by trypan blue dye exclusion, neutral red vital staining and clonogenic assay. The time-effect relationship and growth inhibition of tumor cells by TS were assayed with trypan blue exclusion method. RESULTS: TS at low doses (0.005-0.1 mg.L-1), with dose dependence, was able to kill SMMC-7721, SGC-7901 and HeLa cells. IC50 values for SMMC-7721, SGC-7901 and HeLa cells were 0.007, 0.011 and 0.018 mg.L-1 by trypan blue dye exclusion test and 0.016, 0.055 and 0.078 mg.L-1 by neutral red vital staining test. TS inhibited the clonal forming rate of SMMC-7721 and SGC-7901 significantly with IC50 values of 0.021 and 0.036 mg.L-1, respectively. Only when the cells were continuously treated with TS for more than 8 hours, the drug-induced cell lethality could be displayed and strengthened quickly. The growth of tumor cells was notably inhibited after they were exposed to 0.1 microgram/ml of TS for 12 hours. All the experimental results of antitumor activity in vitro showed that SMMC-7721 was most sensitive to TS among the three kinds of tumor cells. CONCLUSIONS: TS has cytotoxic action on tumor cells cultured in vitro and this lethal effect must have an action process, in which tumor cells are not dead but suffer from deadly injury and lost the capability of unlimited proliferation.  相似文献   
32.
Self-assembled monolayers (SAMs) of alkanethiols and disulfides on gold form organic interfaces with properties largely controlled by the end groups of the molecules composing the film. SAMs provide a unique link between the science of organic surfaces and technologies that seek to exploit their adaptable character. Many techniques are useful for probing the structure of SAMs although only scanning tunneling microscopy (STM) at picoamperes reveals the details of the packing of their end groups at the sub-angstrom level. This review demonstrates that STM effectively tests new types of control over the microscopic structure–property relationships characteristic of SAMs on gold that should prove useful to their application.  相似文献   
33.
We reported an operative case of bilateral coronary artery fistulae to pulmonary artery associated with a giant saccular aneurysm, the largest of which measured 30 x 30 mm. The patient was a 75 year old female who had anginal pain due to coronary steal phenomenon. A continuous murmur was detected. After establishing total cardiopulmonary bypass, two distal orifices of the fistula connected to the main pulmonary artery were closed with 5-0 polypropylene plegeted sutures. Aneurysmorrhaphy was then performed for giant saccular aneurysm. Postoperative course was uneventful.  相似文献   
34.
Hans R. Kricheldorf  Volker D  ring 《Polymer》1992,33(24):5321-5327
The homopolyester of 4-(4′-hydroxyphenoxy)benzoic acid (poly(4-HPBA)), was prepared under two different reaction conditions and compared with a sample provided by another research group. Depending on the synthetic route, different melting points, d.s.c. traces and crystal lattices were found. However, after repeated heating and cooling, one thermodynamically stable modification with a melting point of 370–375°C can be obtained. Copolyesters of 4-hydroxybenzoic acid and 4-(4′-hydroxyphenoxy)benzoic acid were prepared with various molar ratios either in the melt (condensation in bulk) or in solution. These copolyesters were characterized by elemental analyses, 1H n.m.r. spectroscopy, d.s.c. measurements, wide-angle X-ray scattering measurements at various temperatures, and optical microscopy. Whereas copolyesters prepared in solution do not melt below 500°C, those prepared by polycondensation in bulk show melting points down to approximately 260°C and form a nematic melt.  相似文献   
35.
Models and methods are presented for determining practical limits of the packing density of TRISO particles in fuel pebbles for a pebble-bed reactor (PBR). These models are devised for designing and interpreting fuel testing experiments. Two processes for particle failure are accounted for: failure of touching particles at the pressing stage in the pebble manufacturing process and failure due to inner pressure buildup during irradiation. The second process gains importance with increasing fuel temperature, which limits the particle packing density and the corresponding fuel enrichment. Suggestions for improvements to the models are presented.  相似文献   
36.
On-line NMR spectroscopy can beneficially be applied to studies of supercritical and near-critical fluids as an alternative to optical spectroscopy. Up to now high pressure NMR experiments are predominantly accomplished using custom made NMR batch reactors. The authors present a novel high pressure cell with displacement plunger for on-line NMR experiments on compressible fluids which can be used in conjunction with commercially available SCF NMR flow probes. The on-line technique offers advantages compared to stopped flow techniques such as enhanced control of mixture composition and reaction parameters as well as the facility of engagement into the reaction. The new apparatus is used for NMR studies on hydrogen bonding of methanol in near critical and supercritical carbon dioxide up to 403 K and 35 MPa for which data on the chemical shift of the hydroxyl group and methyl group are reported and interpreted.  相似文献   
37.
[Correction Notice: An erratum for this article was reported in Vol 31(3) of Psychotherapy: Theory, Research, Practice, Training (see record 2009-17141-002). This article contained, as Figure 1, an SASB model. The authorship and copyrights for the model were not acknowledged. The following acknowledgement should have been included: "Adapted from Benjamin (1984). Principles of Prediction using Structural Analysis of Social Behavior (SASB). In R. A. Zucker, J. Aronoff, and A. J. Rabin (Eds.), Personality and the Prediction of Behavior (pp. 121- 174). New York: Academic." An apology is offered to the author, Dr. Lorna Smith Benjamin. The particular version used in the article was developed in collaboration with Clinton W. McLemore.] Investigated the internalization of positive aspects of therapist–patient (TP) interactions among 70 patients and their 16 therapists who participated in a 5-yr study (H. H. Strupp et al, unpublished) of time-limited dynamic psychotherapy. Patients sought help for anxiety, depression, or other problems with a clear interpersonal component and qualified for an Axis I or Axis II diagnosis on the Diagnostic and Statistical Manual of Mental Disorders-III (DSM-III). Instruments included the Structural Analysis of Social Behavior and outcome measures of depression, anxiety, and psychological functioning. Patients' intrapsychic functioning became more similar to interpersonal activity in the TP relationship over the course of psychotherapy. Intrapsychic movement toward interpersonal activity in the TP relationship was associated with positive outcome on measures of depression, anxiety, and on independent clinician ratings of patient psychological functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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39.
Argues that in the perception of distance, depth, and visual motion, a single property is often represented by 2 or more stimuli. Two instances of such redundant stimulation are discussed: (a) the various stimuli that represent visual motion and (b) the 2 forms of stimulation by which binocular parallax evokes stereoscopic depth perception. In the case of visual motion, simultaneous operation of redundant stimulation has raised questions concerning the basis of experienced motion and the conditions under which different motion processes are combined. Experiments are described that suggest that some redundant stimuli owe their existence to simple associative learning. Evidence is reviewed that shows that binocular parallax causes stereoscopic depth by means of 2 different perceptual processes. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
40.
The conditions for ferrite and pearlite banding in strip and plate made of structural steels were investigated. Factors found to influence the formation of banded structures were the cooling rate during the γ/α-transformation, the former austenite grain size, and the work-hardened condition of the former austenite. Analyses with the aid of an electron beam microprobe made it possible to demonstrate that the carbon-rich bands correspond locally with banded manganese enrichments, yet that they do not form before the course of the γ/α-transformation as a result of secondary segregation. It was possible to explain the mechanism of action of the influencing factors on the basis of this model.  相似文献   
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