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排序方式: 共有820条查询结果,搜索用时 15 毫秒
31.
B. J. Mayr ÖVE IEEE H. Weinrichter ÖVE IEEE 《e & i Elektrotechnik und Informationstechnik》1997,114(3):123-130
Modern communication systems offer high speed and reliable data transmission services. The quality of these services is achieved by combining coded multi-level modulation techniques and modern digital signal processing (Viterbi-decoding) in the receiver. In this paper we first present an introduction to Trellis Coded Modulation (TCM) and then some new results on unversal techniques adapted for the AWGN-channel as well as for the fading channel. It is shown that TCM is well suited for communication channels with time variant characteristics (e.g. mobile communication channels), especially when our new codes are applied. 相似文献
32.
DA Stoyanovosky R Goldman SS Jonnalagadda BW Day HG Claycamp VE Kagan 《Canadian Metallurgical Quarterly》1996,330(1):3-11
Rapidly growing knowledge about the nature and behaviour of breast cancer has led to many treatment modalities. Consequently, the possibilities of individualizing the treatment of breast cancer increase. The major tool for the determination of an optimal treatment plan is the estimation of the extent of the disease: in other words, staging. As a consequence, together with the expected result of the treatment, the stage of the disease gives information on the prognosis of the patient. Current staging systems insufficiently describe the clinically important features of breast cancer with respect to management and outcome: local and regional extent, invasiveness, aggressiveness, the state of dissemination, and the effectiveness of different treatment modalities. For staging of the local and regional extent, histology plays a prominent role and should be incorporated in future staging systems. Histological workup therefore needs standardisation. Histological parameters as tumour size, grade, nodal status, and vascular invasion are also the most important prognostic factors. Many so-called biological prognostic factors are related to the invasiveness and aggressiveness (metastatic potential) of the tumour, and therefore to the prognosis of the patient. However, these factors do not necessarily predict the effectiveness of certain systemic treatments. Only if the biological foundation of a prognostic factor is completely clarified can treatment be based on this knowledge, and the factor will become a predictor for the treatment effect. Many "biological" prognostic factors do not fulfil this main criterion and are therefore not useful for clinical decision making. A clinically useful staging system covers three primary aims: (1) to guide locoregional treatment, (2) to prognosticate the chance of survival, and (3) to indicate who needs what kind of adjuvant treatment. For the conception of a new staging system the following steps should be taken: standardization of all aspects of histology, identification of regional nodal involvement, and validation of prognostic factors with respect to their predictive value to treatment outcome. 相似文献
33.
The activities of coal companies in the Russian Donetsk Basin (Rostov oblast) are considered, as well as the basic coal characteristics, the potential value of local reserves, and the prospects for the region in current economic conditions. 相似文献
34.
NEDJOUA CHEGHIB MOHAMED ABDAOUI THIERRY CRESTEIL GENEVIÈVE AUBERT JEAN-LOUIS KRAUS 《Polycyclic Aromatic Compounds》2013,33(3):143-153
Through the coupling of substituted benzaldehydes with 8-hydroxy 5-amino methyl quinoline scaffold, a series of new derivatives has been synthesized. In vitro growth inhibitory effects on cancer cell line model have been evaluated. Discussion on the chemical reactivity of these new polycyclic aromatic analogs to generate alkylating species led to the hypothesis that the presence of an imine moiety impedes the formation of quinone methide intermediate and consequently abolishes in part their antiproliferative activity. 相似文献
35.
MS Cookson PC Sogani P Russo J Sheinfeld H Herr G Dalbagni VE Reuter CB Begg WR Fair 《Canadian Metallurgical Quarterly》1997,79(3):432-438
OBJECTIVES: To assess the pathological staging and biochemical progression-free survival (assessed using serum prostate-specific antigen level) of patients with clinically localized prostate cancer using neoadjuvant androgen deprivation therapy (ADT) in combination with radical retropubic prostatectomy (RRP). PATIENTS AND METHODS: A prospective study was carried out on 69 patients with localized prostate cancer who were enrolled in a trial of 3 months of ADT followed by RRP (group 1). These patients were compared with 72 patients matched for age and clinical stage who declined ADT therapy and had RRP concurrently (group 2). Assignment to the individual treatment groups was thus determined by the patient's preference and not the physician's selection. Pathological staging and biochemical progression-free recurrence were compared between the groups. RESULTS: The rate of organ-confined (pT2) tumours was 74% in group 1 and 49% in group 2 (P < 0.01), and the rate of margin-negative tumours was 87% in group 1 and 64% in group 2 (P < 0.01). Within a median follow-up of 35 months, there was no significant difference in biochemical failure between the groups (P = 0.37). Patients with pT2 disease, regardless of treatment, had similar biochemical failure rates. In the patients with margin-positive disease, there was a significantly higher biochemical failure rate in group 1 (P = 0.02). CONCLUSIONS: The rates of organ- and specimen-confined disease were higher among the patients treated with ADT. The preliminary follow-up suggested that patients with pT2 disease after ADT have a biochemical progression-free recurrence rate similar to pT2 patients treated with RRP alone. Additionally, high biochemical failure rates in patients with margin-positive disease after ADT may identify a subset of more biologically aggressive tumours in need of early adjuvant treatment. 相似文献
36.
U. Sh. Shayakhmetov I. M. Valiev K. A. Vasin R. S. Malikov 《Refractories and Industrial Ceramics》1999,40(11-12):499-502
Results of high-temperature creep tests of alumosilicate concretes on a phosphate binder that consists of a mixture of electrocorundum, technical alumina, and pyrophillite are presented. The mixing liquid is H3PO4 and an alumochromophosphate binder. The creep tests have been performed using an installation created by BashNIPIstrom State Enterprise, which makes it possible to test three specimens in one cycle simultaneously. The experimental data on the deformation of the concretes as a function of the pressing pressure, the treatment temperature, and the test conditions (the time, the temperature, and the load) are presented. The present work is the first attempt to study the endurance of materials on phosphate binders under the joint action of high pressures and loads. 相似文献
37.
The mechanical properties of totally ischemic hearts of inbred albino rats were studied. The ischemic myocardium was found to be more sensitive to cyclic loads. Energy deficient contracture of cardiomyocytes is a factor which increases the resistance of the myocardium to mechanical effects. 相似文献
38.
R Poon P Lecavalier P Chan C Viau H H?kansson I Chu VE Valli 《Canadian Metallurgical Quarterly》1995,15(6):455-463
Groups of ten male and female weanling Sprague-Dawley rats were fed diet containing 0, 5, 50, 500 or 5000 ppm of a medium-chain chlorinated paraffin (C14-17, 52% chlorination) for a period of 13 weeks. Increased relative liver weight was observed at 500 and 5000 ppm in females and at 5000 ppm in males. Relative kidney weight was increased at 5000 ppm in both sexes. Serum cholesterol was increased in the females in a dose-related manner starting at 50 ppm. At 5000 ppm, animals of both sexes had elevated hepatic UDP-glucuronosyltransferase activity while only females showed increased aminopyrine N-demethylase activity. Increased urinary N-acetylglucosaminidase activity occurred at 5000 ppm in females. Increased urinary ascorbic acid excretion monitored at week 12 and a decreased hepatic vitamin A level were detected in females receiving the 500 ppm diet and male and female rats at 5000 ppm. Mild, adaptive histopathological changes were detected in the liver of rats of both sexes at 500 and 5000 ppm, and in the thyroid of males and females starting at 500 and 50 ppm respectively. Minimal changes were observed in the kidney proximal tubules of male rats fed the 5000 ppm diet and in the inner medulla tubules of female rats fed the 500 and 5000 ppm diets. These data indicate that the medium-chain chlorinated paraffin produces biochemical and histological changes at dietary levels of greater than or = 50 ppm in females and greater than or = 500 ppm in males. 相似文献
39.
Günther Brauner ÖVE 《e & i Elektrotechnik und Informationstechnik》2000,117(7-8):447-447
40.
E. Uhl ÖVE 《e & i Elektrotechnik und Informationstechnik》2000,117(6):369-374
Ohne Zusammenfassung
Kurzfassung eines Vortrags von Vors.-Dir. Dipl.-Ing. Eduard Uhl anl?sslich einer Siemens-Kundentagung in Alphach. 相似文献