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1.
Solving the N-Queens problem with a binary Hopfield-type network 总被引:3,自引:0,他引:3
Jacek Mańdziuk 《Biological cybernetics》1995,72(5):439-445
The application of a discrete Hopfield-type neural network to solving the NP-Hard optimization problem — the N-Queens Problem (NQP) — is presented. The applied network is binary, and at every moment each neuron potential is equal to either 0 or 1. The network can be implemented in the asynchronous mode as well as in the synchronous one with n parallel running processors. In both cases the convergence rate is up to 100%, and the experimental estimate of the average computational complexity is polynomial. Based on the computer simulation results and the theoretical analysis, the proper network parameters are established. The behaviour of the network is explained. 相似文献
2.
Jacek Kęsy Beata Maciejewska Magdalena Sowa Magdalena Szumilak Krzysztof Kawałowski Maja Borzuchowska Jan Kopcewicz 《Plant Growth Regulation》2008,55(1):43-50
It has been shown that both IAA and ethylene application inhibit flower induction in the short-day plant Pharbitis nil. However application of IAA has elevated ethylene production in this plant, as well. Strong enhancement of ethylene production
is also correlated with the night-break effect, which completely inhibits flowering. In order to determine what the role of
IAA and ethylene is in the photoperiodic flower induction in Pharbitis nil, we measured changes in their levels during inductive and non-inductive photoperiods, and the effects of ethylene biosynthesis
and action inhibitors on inhibition of flowering by IAA. Our results have shown that the inhibitory effect of IAA on Pharbitis nil flowering is not physiological but is connected with its effect on ethylene biosynthesis. 相似文献
3.
The topography of the auriculotemporal nerve (ATN) root system is the main criterion of this nerve classification. Previous publications indicate that ATN may have between one and five roots. Most common is a one- or two-root variant of the nerve structure. The problem of many publications is the inconsistency of nomenclature which concerns the terms “roots”, “connecting branches”, or “branches” that are used to identify the same structures. This study was performed on 80 specimens (40 adults and 40 fetuses) to propose a classification based on: (i) the number of roots, (ii) way of root division, and (iii) configuration of interradicular fibers that form the ATN trunk. This new classification is a remedy for inconsistency of nomenclature of ATN in the infratemporal fossa. This classification system has proven beneficial when organizing all ATN variants described in previous studies and could become a helpful tool for surgeons and dentists. Examination of ATN from the infratemporal fossa of fetuses (the youngest was at 18 weeks gestational age) showed that, at that stage, the nerve is fully developed. 相似文献
4.
5.
Photochemical labeling of bovine pancreatic ribonuclease A with 8-azidoadenosine 3',5'-bisphosphate 总被引:1,自引:0,他引:1
A simple method has been developed for the preparation of 5'-32P-labeled 8-azidoadenosine 3',5'-bisphosphate (p8N3Ap) for use in photoaffinity labeling studies. Irradiation of a complex between p8N3Ap and bovine pancreatic ribonuclease A (RNase A) with light of 300-350 nm led to the covalent attachment of the nucleotide to the enzyme. RNase A could also be labeled in the dark with prephotolyzed p8N3Ap. In either case, the nucleotide reacted with the same tryptic peptide, encompassing amino acids 67-85 of the protein. The site of labeling was determined to be either Thr-78 or Thr-82, both of which are close to or at the pyrimidine binding site of the enzyme. This result is consistent with recent nuclear magnetic resonance and X-ray studies which indicate that 8-substituted adenine nucleotides interact with the pyrimidine binding site of RNase A. 相似文献
6.
Marta Zygulska Antonin Eigel Christa Aulehla-Scholz Jacek J. Pietrzyk Jürgen Horst 《Human genetics》1991,86(3):292-294
Summary Out of a population of 138598 infants born in southern Poland between 1987 and 1989, and screened for phenylketonuria (PKU), 28 cases were ascertained giving an incidence of 1 in 5000. DNA from 22 of these probands and their parents was isolated and eight polymorphic restriction sites were analyzed within the phenylalanine hydroxylase gene region. Twenty-one different haplotypes (HT) were revealed, five of them representing new categories. The most common haplotypes among those carrying normal alleles were: HT1 (27.3%) and HT4 (11.4%). Within the group of haplotypes with mutant alleles the most frequent was HT2 (56.8%), whereas the frequency of this haplotype in other European populations, such as French, Danish and German, ranged from 12% to 24%. HT3, being the most common in Danish (38%), and relatively frequent in the other western European (13–14%) populations, appeared to be very rare in our sample (2.3%). The mutation of codon 408 (exon 12, CT, ArgTrp), which has been described to be tightly linked to HT2, was tested on amplified DNA by dot-blot hybridization. This mutation was found in 25 out of 44 proband chromosomes. In one case it was linked to HT5, in the remaining 24 to HT2. Our results confirm molecular heterogeneity of PKU haplotypes, as well as their significant interpopulation variation. 相似文献
7.
A membrane with an arbitrary distribution of fixed charges inside and on its surfaces is considered. A procedure for calculating
the local electrostatic potential at an arbitrary point of the system is described and its validity discussed. This procedure
is based on the linearization of the 3-dimensional Poisson-Boltzmann equation around an exact 1-dimensional solution. 相似文献
8.
The localization of multiple sites on 16S RNA which are cross-linked to proteins S7 and S8 in Escherichia coli 30S ribosomal subunits by treatment with 2-iminothiolane. 总被引:17,自引:13,他引:4 下载免费PDF全文
RNA-protein cross-links were introduced into E. coli 30S ribosomal subunits by reaction with 2-iminothiolane followed by a mild ultraviolet irradiation treatment. After removal of non-reacted protein and partial nuclease digestion of the cross-linked 16S RNA-protein moiety, a number of individual cross-linked complexes could be isolated and the sites of attachment of the proteins to the RNA determined. Protein S8 was cross-linked to the RNA at three different positions, within oligo-nucleotides encompassing positions 629-633, 651-654, and (tentatively) 593-597 in the 16S sequence. Protein S7 was cross-linked within two oligonucleotides encompassing positions 1238-1240, and 1377-1378. In addition, a site at position 723-724 was observed, cross-linked to protein S19, S20 or S21. 相似文献
9.
A procedure is described for the purification of the enzyme indol-3-ylacetylglucose:myo-inositol indol-3-ylacetyltransferase (IAA-myo-inositol synthase). This enzyme catalyzes the transfer of indol-3-ylacetate from 1-0-indol-3-ylacetyl-β-d-glucose to myo-inositol to form indol-3-ylacetyl-myo-inositol and glucose. A hexokinase or glucose oxidase based assay system is described. The enzyme has been purified approximately 16,000-fold, has an isoelectric point of pH 6.1 and yields three catalytically inactive bands upon acrylamide gel electrophoresis of the native protein. The enzyme shows maximum transferase activity with myo-inositol but shows some transferase activity with scyllo-inositol and myo-inosose-2. No transfer of IAA occurs with myo-inositol-d-galactopyranose, cyclohexanol, mannitol, or glycerol as acyl acceptor. The affinity of the enzyme for 1-0-indol-3-ylacetyl-β-d-glucose is, Km = 30 micromolar, and for myo-inositol is, Km = 4 millimolar. The enzyme does not catalyze the exchange incorporation of glucose into IAA-glucose indicating the reaction mechanism involves binding of IAA glucose to the enzyme with subsequent hydrolytic cleavage of the acyl moiety by the hydroxyl of myo-inositol to form IAA myo-inositol ester. 相似文献
10.
The effects of the acylcyclohexanedione-type growth retardant prohexadione calcium on seedling growth and endogenous levels of immunoreactive phytohormone-like substances in shoots of wheat ( Triticum aestivum L. cv. Kanzler) and oilseed rape ( Brassica napus L. ssp. napus cv. Lirajet) were studied. After treatment of seedlings with increasing retardant concentrations in hydroponics, plant height and fresh weight of shoots were reduced by up to 40%. Concomitantly, the amount of immunoreactive gibberellins decreased, on a fresh weight basis, when compared with levels in the shoots of control plants. In contrast, the levels of abscisic acid and dihydrozeatin riboside and isopentenyladenosine-type cytokinins were considerably elevated by the growth retardant. The content of 3-indoleacetic acid decreased slightly. These results suggest that, in addition to its effect on gibberellin content, prohexadione calcium also influences the levels of endogenous abscisic acid and cytokinins. 相似文献