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721.
Sambasivarao Kotha Kalyaneswar Mandal KapildevK. Arora V.R. Pedireddi 《Advanced Synthesis \u0026amp; Catalysis》2005,347(9):1215-1218
The synthesis of a [1.1.6] metapara cyclophane derivative, 1,5(1,4),3(1,3)‐tribenzenacycloundecaphan‐8‐ene‐6,11‐dione, has been achieved via the Suzuki–Miyaura cross‐coupling of α,α′‐dibromo‐m‐xylene with an arylboronic acid derivative followed by an allylation and ring‐closing metathesis reaction sequence. 相似文献
722.
A first reported method of measuring coupling capacitance (both inter- and intralevel) between any two lines in the presence of any other lines in a very large scale integration (VLSI) chip, to an accuracy of atto-farad range, is discussed. The setup simply requires dc current measurement and the method has been tested for 180 nm and 130 nm technologies. Furthermore, the method can be easily implemented for on-wafer e-test measurement in a fab, to study die-to-die and wafer-to-wafer coupling capacitance variation due to manufacturing process variation. In one process, it has been observed that the coupling capacitance between parallel lines could vary as much as 17%. 相似文献
723.
O. K. Lim J. S. Arora 《International journal for numerical methods in engineering》1987,24(10):1827-1840
A recently developed recursive quadratic programming (RQP) algorithm is applied to dynamic response design problems. The algorithm incorporates updated Hessians of the Lagrange function and uses an active set strategy in which only a subset of the constraints is included in the direction finding QP subproblem. Hessian updating with dynamic response constraints presents some difficulties. The primary difficulty is that the total number of constraints and the location of time points where they have to be imposed can change from iteration to iteration. This can cause inconsistencies in Hessian updating if proper numerical procedures are not used. A numerical procedure to handle the situation is developed, implemented and evaluated. Automatic restarting procedures are necessary for proper convergence of the algorithm. The new algorithm is robust as well as more efficient than the purely linear algorithm. The active set strategy plays an important role for application to dynamic response problems. The RQP algorithms that do not use such a strategy are not applicable to this class of problems. 相似文献
724.
725.
A design is presented for a digital filter, using the powerful alternation theorem and Remez exchange algorithm. The approach unifies all types of filters and the algorithm developed is exceedingly efficient as it is capable of designing a filter with 100-point impulse response in ca. 20 s. 相似文献
726.
The d.c. electrical conductivity and thermoelectric power of CuWO4 have been measured in the temperature range 300 to 700 K on unannealed and annealed single crystals and on polycrystalline pellets. It has been found that CuWO4 is an n-type semiconductor. Relevant conduction mechanisms appropriate to the regions below and above 455 K are discussed on the basis of the experimental data on activation energy, mobility and carrier concentration. 相似文献
727.
Amides resembling ceramide (fatty acyl sphingosine) were synthesized and tested in vitro for their effects on the rat brain
β-galactosidase which hydrolyzes galactosyl ceramide. The N-decanoyl derivative of 2-amino-2-methyl-1-propanol was most effective,
giving a 34% stimulation at 0.15 mM concentration and a 60% stimulation at maximal levels. Addition of a hydroxyl group in
the 3 position reduced the degree of stimulation, as did increasing or decreasing the length of the fatty acid portion. Omission
of the branched methyl group resulted in inhibition instead of stimulation. Kinetic analysis indicates that the stimulator
does not affect the binding of substrate to enzyme, but does speed the rate of hydrolytic action. Stimulation was also observed
with the cerebrosidase in spleen and kidney. It is suggested that the stimulators act on an enzyme site other than the substrate-active
site. 相似文献
728.
Survey of multi-objective optimization methods for engineering 总被引:28,自引:3,他引:25
R.T.?Marler J.S.?Arora Email author 《Structural and Multidisciplinary Optimization》2004,26(6):369-395
A survey of current continuous nonlinear multi-objective optimization (MOO) concepts and methods is presented. It consolidates and relates seemingly different terminology and methods. The methods are divided into three major categories: methods with a priori articulation of preferences, methods with a posteriori articulation of preferences, and methods with no articulation of preferences. Genetic algorithms are surveyed as well. Commentary is provided on three fronts, concerning the advantages and pitfalls of individual methods, the different classes of methods, and the field of MOO as a whole. The Characteristics of the most significant methods are summarized. Conclusions are drawn that reflect often-neglected ideas and applicability to engineering problems. It is found that no single approach is superior. Rather, the selection of a specific method depends on the type of information that is provided in the problem, the users preferences, the solution requirements, and the availability of software. 相似文献
729.
Although ceramide signaling pathways have been implicated in cell death, neither their role in hepatocellular death nor the cellular mechanisms mediating ceramide-induced cell death are known. The mitochondrial membrane permeability transition (MMPT) has been proposed as a common final pathway in cell death. Thus the aims of our study were to determine if ceramides cause hepatocellular death by necrosis and not apoptosis as confirmed by morphology and the absence of internucleosomal DNA cleavage. Ceramide-mediated hepatocyte necrosis was acyl chain-length, concentration, and time-dependent. Ceramides induced cell necrosis was associated with adenosine triphosphate (ATP) depletion and mitochondrial depolarization suggesting that ceramides caused mitochondrial dysfunction. In isolated mitochondria, ceramides induced the cyclosporine A-sensitive MMPT in an acyl chain-length and concentration dependent manner. Ceramide toxicity was specific as the less potent dihydro form did not induce cell necrosis, significant ATP depletion, mitochondrial depolarization nor the MMPT. In conclusion, ceramide induced cell death is acyl-chain length dependent and mediated by the MMPT. These data show for the first time that ceramide acts as a mediator of hepatocyte necrosis by causing mitochondrial failure. 相似文献
730.
AE Rader R Lazebnik CD Arora J Franklin FW Abdul-Karim 《Canadian Metallurgical Quarterly》1997,41(4):1073-1078
OBJECTIVE: To determine the significance of an atypical squamous cells of undetermined significance (ASCUS) diagnosis in patients 18 years or younger. STUDY DESIGN: From June 1994 to June 1995, 630 cervicovaginal smears were performed on patients 18 years or younger (mean age 16.4, range 14-18) at University Hospitals of Cleveland. Of these patients, 69 (10.9%) were diagnosed with ASCUS or ASCUS with a qualifying statement. Follow-up cervicovaginal smears, biopsies and charts were reviewed for a 12-18-month period following the initial diagnosis of ASCUS. RESULTS: The study population was sexually active: 63% were gravid, 21% were multigravid, 68% had a history of sexually transmitted diseases (STDs), and 32% had multiple STDs. Follow-up cervicovaginal smears or biopsies were obtained on 46 patients (32 cervicovaginal smears and 14 biopsies/endocervical curettage cases). Mild to moderate dysplasia was identified in 21.6% of patients (10.8% on cervicovaginal smears and 10.8% on biopsies), and a repeat diagnosis of ASCUS was given in 37%. In patients with a repeat diagnosis of ASCUS, a follow-up cervicovaginal smear or biopsy revealed dysplasia in an additional 13%. The overall rate of dysplasia was 34.7%. CONCLUSION: Regardless of age, the diagnosis of ASCUS in a sexually active patient population has significant implications. Furthermore, we recommend that these patients be managed the same way as high-risk adult patients. 相似文献