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61.
Since natural proteins are the products of a long evolutionary process, the structural properties of present-day proteins should depend not only on physico-chemical constraints, but also on evolutionary constraints. Here we propose a model for protein evolution, in which membranes play a key role as a scaffold for supporting the gradual evolution from flexible polypeptides to well-folded proteins. We suggest that the folding process of present-day globular proteins is a relic of this putative evolutionary process. To test the hypothesis that membranes once acted as a cradle for the folding of globular proteins, extensive research on membrane proteins and the interactions of globular proteins with membranes will be required.  相似文献   
62.
In the field of data mining, confidence and support are often used to measure the quality of a rule. Pareto-optimal rules, which are Pareto-optimal in terms of confidence and support maximization, have an interesting characteristic that Pareto-optimal rules maximize other various rule evaluation criteria. In this paper, we examine the effectiveness of designing classifiers from Pareto-optimal rules. We consider not only Pareto-optimal rules but also near Pareto-optimal rules. To show the effectiveness, we compare classifiers obtained from Pareto-optimal and near Pareto-optimal rules with classifiers obtained from the rules that have large value in terms of other different rule evaluation criteria. Eight criteria are examined in this paper: CF, confidence, cover, Laplace, lift, random, slave, support. Through computational experiments, we show that classifiers obtained from Pareto-optimal rules have higher accuracy than those from rules extracted according to the other criteria. This work was presented in part and awarded as Young Author Award at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008  相似文献   
63.
In this paper, a rapid and simple method to determine the optimal temperature conditions for denaturant electrophoresis using a temperature-controlled on-chip capillary electrophoresis (CE) device is presented. Since on-chip CE operations including sample loading, injection and separation are carried out just by switching the electric field, we can repeat consecutive run-to-run CE operations on a single on-chip CE device by programming the voltage sequences. By utilizing the high-speed separation and the repeatability of the on-chip CE, a series of electrophoretic operations with different running temperatures can be implemented. Using separations of reaction products of single-stranded DNA (ssDNA) with a peptide nucleic acid (PNA) oligomer, the effectiveness of the presented method to determine the optimal temperature conditions required to discriminate a single-base substitution (SBS) between two different ssDNAs is demonstrated. It is shown that a single run for one temperature condition can be executed within 4 min, and the optimal temperature to discriminate the SBS could be successfully found using the present method.  相似文献   
64.
The interaction between a nonionic polymer and a hydrocarbon or fluorocarbon surfactant has been investigated by means of surface tension, viscosity, electroconductivity, fluorescence probing, solubilization of a waterinsoluble dye, and electron spin resonance (ESR). The systems studied consisted of polyvinylpyrrolidone (PVP) with lithium dodecyl sulfate (LiDS) or lithium perfluorooctane sulfonate (LiFOS). Surface tension measurements indicated that formation of PVP-surfactant complex is more favorable in the PVP-LiFOS system than in the PVP-LiDS system, and that the adsorbed amount of LiFOS is less than that of LiDS, although the CMCs of the surfactants are almost the same. In the PVP-LiFOS system, the relative viscosity and the solubilized amount of a water-insoluble dye showed a maximum at a certain concentration of LiFOS in the region between two transitions observed in the surface tension, where also a change in the slope of the electroconductivity is observed. These results indicate that shielding of effective charge of the PVP-LiFOS complex causes a conformational change of PVP wrapped around the aggregate of LiFOS with an increase of free surfactant in the bulk phase. The conformational change can be correlated with microenvironmental properties of PVP-surfactant complexes. The microviscosity estimated with ESR indicated that the headgroups of LiFOS adsorbed on PVP are less tightly packed than those of LiFOS micelles, while an opposite result was obtained in the PVP-LiDS system. In particular, the marked high viscosity at a low concentration of LiFOS in the PVP-LiFOS system can probably be attributed to rigidity of the fluorocarbon chain of LiFOS.  相似文献   
65.
The female-produced sex pheromone of the scarab beetle Phyllophaga lanceolata was identified as the methyl ester of an essential amino acid, l-leucine. During field testing, 239 male P. lanceolata were caught in traps baited with l-leucine methyl ester. l-Isoleucine and l-valine methyl esters, similar in structure to l-leucine methyl ester and previously identified as female-produced sex pheromone compounds employed by other Phyllophaga species, were also tested. Addition of l-valine or l-isoleucine methyl esters to the l-leucine methyl ester in 1:1 ratios completely inhibited attraction of P. lanceolata males. Males of P. squamipilosa were also captured using l-leucine methyl ester. This is the first record of P. squamipilosa from Kansas.  相似文献   
66.
When guinea pig bone marrow cells were incubated in the presence of 10−8 to 10−6 M platelet activating factor (PAF) for 24 to 72 hr, microbicidal activity againstCandida parapsilosis of cells was augmented. This augmentation was inhibited by PAF-specific antagonists, CV6209 or FR900452. PAF-specific binding sites with a high affinity were found on guinea pig bone marrow cells. Carrageenan or 2-chloroadenosine, reagents known to be preferentially cytotoxic to macrophages, abolished the microbicidal activity of PAF-treated bone marrow cells. Macrophages prepared from the peritoneal cavity, however, acquired no appreciable microbicidal action by treatment with PAF. These observations suggest that PAF may affect a class of guinea pig bone marrow cells through binding to receptors specific to PAF, resulting in activation and/or induction of differentiation of monocyte-macrophage lineage cells.  相似文献   
67.
This paper describes a new integrated service network using packetized voice/data technology which was developed in consideration of the sophisticated service demands for voice, data, and facsimile communication. A major problem in constructing this network is in the local distribution network, i.e., the subscriber interface unit, the local end office, and the subscriber loop which connects them. The concepts, choice of design parameters, and laboratory test results of the packetized service integration network are briefly discussed.  相似文献   
68.
The sensitivity verification with the ultrahigh-frequency (UHF) method will be discussed in this paper. The sensitivity line with the UHF method based on the conventional (IEC 60270) one is different in the radial position of the defects inside gas-insulated substation (GIS), because transverse-electromagentic mode can be more weakened while transverse electric (TE)/transverse magnetic (TM) modes can be more enhanced as the defect comes close to the enclosure than the conductor. The result makes it difficult to detect the free particle with IEC 60270. A unique sensitivity verification, which is combined with real-time PD identification method, first enables us to identify the defects and thereafter to calibrate the apparent charge of each specified defect according to the sensitivity line.  相似文献   
69.
Electron beam misalignment in a submillimeter-wave gyrotron strongly affects its total efficiency as well as excitation of rotating and counterrotating modes. Some of misalignment phenomena were studied theoretically and experimentally.  相似文献   
70.
The sex pheromone of Phyllophaga (Phytalus) georgiana was characterized as valine methyl ester, tentatively the l-enantiomer. This is the first sex pheromone identified from the Phyllophaga subgenus Phytalus. The pheromone was extracted from female glands, the active component isolated by coupled gas chromatography–electroantennogram detection analysis, characterized by mass spectrometry, and shown to be active in field tests. The seasonal flight pattern was determined for P. georgiana as well as for three other species, P. anxia (both northern and southern genitalic forms), P. gracilis, and P. postrema. The latter three species were captured in traps baited with l-isoleucine methyl ester. Sridhar Polavarapu, deceased May 7, 2004. We dedicate this publication to our friend and colleague.  相似文献   
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