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71.
Mucignat-Caretta C 《Journal of chemical ecology》2002,28(9):1853-1863
Male pheromones are believed to attract females and repel male mice in open field tests but, when tested in more complex environments, they can attract male mice in usually avoided areas. Females were tested in an apparatus with one dark and one light side, in the absence or presence of male urine or the major urinary proteins (MUPs) bearing the natural ligands. Diestrous females were slower in leaving from the dark area when male urine or MUPs were present in it. Estrogen-primed females showed the opposite behavior, with an increase in the same latency. The light-avoidance behavior of prepubertal females, or females reared without males was not influenced by the presence of male chemosignals. The results show that adult female mice can react to MUP-borne volatiles as to adult male urine and use them as cues of male mice, if they were previously exposed to male cues during infancy. MUP-borne molecules are, thus, the olfactory trace of males in the environment and modulate mice exploratory behavior. 相似文献
72.
Stefano Messelodi Carla Maria Modena Michele Zanin 《Pattern Analysis & Applications》2005,8(1-2):17-31
The paper presents a real-time vision system to compute traffic parameters by analyzing monocular image sequences coming from pole-mounted video cameras at urban crossroads. The system uses a combination of segmentation and motion information to localize and track moving objects on the road plane, utilizing a robust background updating, and a feature-based tracking method. It is able to describe the path of each detected vehicle, to estimate its speed and to classify it into seven categories. The classification task relies on a model-based matching technique refined by a feature-based one for distinguishing between classes having similar models, like bicycles and motorcycles. The system is flexible with respect to the intersection geometry and the camera position. Experimental results demonstrate robust, real-time vehicle detection, tracking and classification over several hours of videos taken under different illumination conditions. The system is presently under trial in Trento, a 100,000-people town in northern Italy. 相似文献
73.
74.
M. Bastić Lj. Bastić J. A. Jovanović G. Spiteller 《Journal of the American Oil Chemists' Society》1977,54(11):525-527
The sterol fraction of unsaponifiable matter obtained from a Yugoslav pumpkin seed ripening was investigated by gas liquid chromatography on a glass capillary column. It contained at least 14 different sterols ten of which were identified primarily by combined gas chromatography-mass spectrometry as cholesterol, brassicasterol, campesterol, stigmasterol, 24-methylcholest-7-en-3β-ol, Δ7,22,25-stimastatrien-3β-ol, α-spinasterol, Δ7,25-stigmastadien-3β-ol, Δ7,25-stigmastenol, and Δ7-avenasterol. It was shown that the unidentified sterols in the oil obtained from a Chinese pumpkin seed were Δ7,25-stigmastadien-3β-ol, and Δ7,22,25-stigmastatrien-3β-ol,. There was practically no difference in the composition of Yugoslav and Chinese pumpkin seed oil, the main characteristic of which was the presence of Δ7-sterols as was already stated by Sucrow. 相似文献
75.
Chemical signals modulate aggressive behavior in mice. For example, male urinary cues enhance aggression against other adults: a resident mouse attacks a male but not a castrated intruder, unless it is anointed with male urine. Our purpose was to understand whether molecules excreted with urine also act as aggression triggers in a different context. Therefore, the effect of urine, or molecules purified from urine, voided by different animals (males or females), was tested on the aggression of male mice against pups. Latency to the first attack, percentage of pups receiving the first attack, and percentage of attacked pups after 5 and 15 min were recorded. At variance with intermale aggression, male urinary chemosignals sprayed on pups reduced infanticide, while female urine did not. Male urine also delayed infanticide when compared to female urine. Pups anointed with low molecular weight dialyzed urine and with the high molecular weight protein fraction were attacked later than controls. Pups anointed with Major Urinary Proteins (MUPs) also were attacked later. The volatiles retained by MUPs act in the same way as adult male urine. MUPs and their ligands did not modify biting of food items. The results show that mice do not perceive male chemosignals as compulsory aggression triggers but rather can consistently and differentially shape their behavior in response to the same molecules according to different contextual events. 相似文献
76.
Identification of potent human anti-IL-1RI antagonist antibodies 总被引:4,自引:0,他引:4
Fredericks ZL Forte C Capuano IV Zhou H Vanden Bos T Carter P 《Protein engineering, design & selection : PEDS》2004,17(1):95-106
Interleukin-1 (IL-1) blockade by IL-1 receptor antagonist benefits some arthritis patients by reducing joint damage. This fact inspired us to develop antagonist human therapeutic antibodies against IL-1R(I) using phage libraries that display single-chain variable fragment (scFv) antibody fragments. Panning libraries against human IL-1R(I) generated 39 unique scFv-phage whose binding to IL-1R(I) was competed by IL-1 ligands. Fifteen of these scFv-phage, identified using IL-1R(I)-binding assays and dissociation rate ranking, were reformatted as scFv-Fc and IgG(4) molecules. The ease of producing antibodies in the scFv-Fc format permitted rapid identification of four lead clones (C10, C13, C14, C15) that inhibit NF-kappaB nuclear translocation induced by IL-1. Reformatting these clones as IgG(4) molecules increased their inhibition potency by =24-fold. C10 IgG(4) is the most potent antagonist of IL-1alpha (26 nM IC(50)) and IL-1beta (18 nM IC(50)) in the NF-kappaB bioassay, although less potent than IL-1ra ( approximately 0.4 nM IC(50)). C10 is the highest affinity clone for human IL-1R(I) (K(D) approximately 60 nM). Flow cytometry indicates that several lead clones bind cell-surface cynomolgus or murine IL-1R(I), characteristics advantageous for preclinical toxicology and efficacy studies. This study demonstrates the utility of scFv-Fc fusion proteins for rapid screening of clones derived from phage libraries to identify antibody leads with therapeutic potential. 相似文献
77.
We present C2 quasi-interpolating schemes with tension properties. The B-splines like functions used in the quasi-interpolanting schemes are parametric cubic curves and their shape can be easily controlled via tension parameters which have an immediate geometric interpretation. Applications to the problem of approximation of curves with shape-constraints are discussed. 相似文献
78.
Poly(ethylene terephthalate) (PET) is one of the most commonly employed polymers in the textile industry. Its relevance as a source of evidence in the reconstruction of criminal cases is nevertheless very limited because the properties and morphologies of fibers from different producers tend to be very similar. By integrating bands, obtained on single fibers by infrared (IR) microscopy, associated with trans and gauche conformation and to the O-H end-groups of the molecules, a method is proposed that can discriminate otherwise similar PET fibers. The absorbancies at 1370 and at 846 cm(-1) relative, respectively, to the gauche and trans conformation, were measured and ratioed. The end-group content was evaluated by ratioing the absorbancies of the signals at 3440 and at 874 cm(-1). Relative standard deviation (R. S. D.) was 1% for repetitive analyses on the same location of the same single fiber. Precision was reduced if the ratios were measured along the length of a single fiber (R. S. D. = 3%) and even further when different fibers of the same sample were examined (R. S. D. varied from 2 to 10%). This simple method can greatly enhance the evidential value of PET fibers by subclassifying them, thus helping the Court to better assess their significance. 相似文献
79.
This paper introduces the computer security domain of anomaly detection and formulates it as a machine learning task on temporal sequence data. In this domain, the goal is to develop a model or profile of the normal working state of a system user and to detect anomalous conditions as long-term deviations from the expected behavior patterns. We introduce two approaches to this problem: one employing instance-based learning (IBL) and the other using hidden Markov models (HMMs). Though not suitable for a comprehensive security solution, both approaches achieve anomaly identification performance sufficient for a low-level focus of attention detector in a multitier security system. Further, we evaluate model scaling techniques for the two approaches: two clustering techniques for the IBL approach and variation of the number of hidden states for the HMM approach. We find that over both model classes and a wide range of model scales, there is no significant difference in performance at recognizing the profiled user. We take this invariance as evidence that, in this security domain, limited memory models (e.g., fixed-length instances or low-order Markov models) can learn only part of the user identity information in which we're interested and that substantially different models will be necessary if dramatic improvements in user-based anomaly detection are to be achieved. 相似文献
80.
Bassarello C Cimino P Bifulco G Boger DL Smith JA Chazin WJ Gomez-Paloma L 《Chembiochem : a European journal of chemical biology》2003,4(11):1188-1193
We report the NMR solution structure of (+)-CPI-indole (CPI, 1,2,8,8a-tetrahydrocyclopropa[c]pyrrolo[3,2-e]indol-4(5H)-one), an agent belonging to the CC-1065/duocarmycin family of antitumor compounds. This (+)-CPI-indole structure is covalently bound to d(G(1)ACTAATTGTC(11))-d(G(12)TCAATTAGTC(22)), a synthetic DNA duplex containing a high-affinity binding site. The three-dimensional structure has been determined by several cycles of restrained molecular dynamics calculations with a total of 563 NMR-derived constraints, both in vacuo and by using the generalized Born solvent continuum model. In-depth analysis of the structure of this ligand-DNA complex led to a detailed knowledge of the bound state conformation of the CPI-indole, the most simplified agent related to CC-1065 and duocarmycins, the parent members of a family of extremely potent antitumor compounds. Comparison of the CPI-indole bound conformation with those previously found for (+)-duocarmycin SA (DSA), its unnatural enantiomer (-)-DSA, and the demethoxylated analogue (+)-DSI in their DNA complexes provided additional evidence of the tight correlation between the catalytic effect exerted by DNA on the alkylation reaction and the extent of angular twist between the two planar heteroaromatic subunits of these agents. Additionally, comparison of the structural features of the DNA-bound state of a "naked" ligand, such as CPI-indole, with those of various other duocarmycin agents provided useful information for the interpretation of the observed effects on chemical reactivity of the different substitution patterns at the hemispheres of these types of complex. 相似文献