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51.
Christer Löfstedt Bill S. Hansson Miklos Tòth Gabor Szöcs Vincas Buda Marie Bengtsson Nils Ryrholm Mats Svensson Ernst Priesner 《Journal of chemical ecology》1994,20(1):91-109
The noctuid sibling taxaDiachrysia chrysitis s. str. andD. tutti, of yet uncertain taxonomic status, have previously been shown to possess differences in morphology and to be attracted to different mixtures of the two presumed pheromone components (Z)-5-decenyl acetate and (Z)-7-decenyl acetate. TypicalD. tutti males (clearly broken forewing marking) are known to respond to a 2: 100 mixture of the two isomers, whereasD. chrysitis males (unbroken marking) are attracted to a 100: 10 mixture. We investigated female pheromone production and male electroantennographic (EAG) response inDiachrysia families raised in the laboratory from field-collected gravid females. Extracts of individual females from typicalD. tutti andD. chrysitis families were subjected to gas chromatography with simultaneous flame ionization and electroantennographic detection. All females produced mixtures of Z5- and Z7-10:OAc, but femaleD. chrysitis produced predominantly Z5-10:OAc and the antennae of their brothers responded more strongly to the Z5 peak than to the Z7-10:OAc peak, whereas the opposite was true forD. tutti families. The pheromone components were shown to be biosynthesized from hexadecanoic and tetradecanoic acid, respectively by Z11-desaturation followed by chain shortening, reduction, and acetylation. The EAG responses of males trapped with the typicalD. tutti andD. chrysitis blends, as well as with an intermediate blend, were investigated. Males trapped with theD. tutti mixture almost exclusively had a clearly broken wing marking and showed strongest EAG response to Z7-10:OAc. The intermediate blend and theD. chrysitis mixture gave more mixed catches, but with a prevalence of males with an unbroken (or almost unbroken) wing marking and with a higher mean response to Z5-10:OAc. Some males with typicalD. tutti EAG responses were attracted in the field to theD. chrysitis pheromone. In the flight tunnel someD. chrysitis males were attracted also to theD. tutti mixture. This indicates that cross attraction may take place between the two taxa under natural conditions. 相似文献
52.
Article presents the state of the art problem of comparing photo portrait and the corresponding hand-drawn portrait (sketch). Proposed novel methods of automatic sketch generation. The result of the application of this methods on two popular face database are given. It is shown that for sketch recognition you can use simple system. 相似文献
53.
This paper describes the pulsed constant current anodization of n+ and p+-GaAs in ethylene glycol–water–tartaric acid (AGW) mixture, up to 17mAcm–2. A 0.26m thick film is obtained for a final voltage of 135V at 4.3mAcm–2 pulsed current density. Cyclic voltammetry showed that the initial growth of a monolayer anodic oxide can be described by a charge transfer with uncompensated cell resistance model. The relationship between peak current, peak voltage and scan rate has been verified for this process, based on the above model. 相似文献
54.
To minimize risks from pathogenic prion proteins, particular tissues from bovines and other ruminants have been declared specified risk materials (SRMs), which are required to be removed from the food chain. However, in particular for the sympathetic trunk (ST) as a part of the autonomous nervous system (ANS), which represents a potential transfer route for abnormal prion proteins (PrP(Sc)), this is not the case. Consequently, its destination during cutting procedures deserves attention. In this survey, the handling of the ST in beef cutting plants was recorded during ongoing work. To ease these observations, the ST was separated into five parts, and eight destinations for cuts were identified. By means of an observation sheet, the destination of the respective tissue was recorded. About one-third of the ST went into human consumption, another one-third was disposed of as SRMs, and the last one-third was used for nonfood purposes or disposed of. The rear thoracic and sacral ganglia primarily remained naturally connected to the bones going as SRMs. The stellate, front thoracic, and lumbar ganglia went in a different percent into the food chain. Frequently, workers in the same plant decided differently, even from case to case, on the destination of the tissue, which indicates a lack of standardization. 相似文献
55.
Low-loss low-confinement GaAs-AlGaAs DQW laser diode with opticaltrap layer for high-power operation
Buda M. van der Vleuten W.C. Iordache Gh. Acket G.A. van de Roer T.G. van Es C.M. van Roy B.H. Smalbrugge E. 《Photonics Technology Letters, IEEE》1999,11(2):161-163
A low-confinement asymmetric GaAs-AlGaAs double-quantum-well molecular-beam-epitaxy grown laser diode structure with optical trap layer is characterized, The value of the internal absorption coefficient is as low as 1.4 cm-1, while keeping the series resistance at values comparable cm with symmetrical quantum-well gradient index structures in the same material system. Uncoated devices show COD values of 35 mW/μm. If coated, this should scale to about 90 mW/μm. The threshold current density is about 1000 A/cm2 for 2-mm-long devices and a considerable part of it is probably due to recombination in the optical trap layer. Fundamental mode operation is limited to 120-180 mW for 6.5-μm-wide ridge waveguide uncoated devices and to 200-300 mW for 13.5-μm-wide ones, because of thermal waveguiding effects. These values are measured under pulsed conditions, 10 μs/l ms 相似文献
56.
The synthesis of mesoporous MCM-41 silica materials was investigated at various conditions. A series of ordered mesopores MCM-41 silica materials was synthesized in concentrated reaction mixtures. The influence of water concentration at the constant ratio of the remaining reagents on the morphology and structural parameters of MCM-41 was studied. Hexadecyltrimethylammonium bromide CTAB was used as a structure-directing agent. The pore size, the wall thickness and cylindrical pores array were characterized by powder X-ray diffraction and nitrogen adsorption. The presented results show that in concentrated reaction mixtures, the pore size and the thickness of the pore walls remain practically constant. However, the dimensions of silica particles depend strongly on the water concentration. A high regularity of pore structure for large MCM-41 particles synthesized in concentrated solution was supported by independent AFM technique. 相似文献
57.
Roxana Mihaela Chiorescu Mihaela Mocan Andreea Ioana Inceu Andreea Paula Buda Dan Blendea Sonia Irina Vlaicu 《International journal of molecular sciences》2022,23(21)
Atherosclerosis and its clinical manifestations, coronary and cerebral artery diseases, are the most common cause of death worldwide. The main pathophysiological mechanism for these complications is the rupture of vulnerable atherosclerotic plaques and subsequent thrombosis. Pathological studies of the vulnerable lesions showed that more frequently, plaques rich in lipids and with a high level of inflammation, responsible for mild or moderate stenosis, are more prone to rupture, leading to acute events. Identifying the vulnerable plaques helps to stratify patients at risk of developing acute vascular events. Traditional imaging methods based on plaque appearance and size are not reliable in prediction the risk of rupture. Intravascular imaging is a novel technique able to identify vulnerable lesions, but it is invasive and an operator-dependent technique. This review aims to summarize the current data from literature regarding the main biomarkers involved in the attempt to diagnose vulnerable atherosclerotic lesions. These biomarkers could be the base for risk stratification and development of the new therapeutic drugs in the treatment of patients with vulnerable atherosclerotic plaques. 相似文献
58.
Low loss, thin p-clad 980-nm InGaAs semiconductor laser diodes with an asymmetric structure design 总被引:1,自引:0,他引:1
Buda M. Hay J. Tan H.H. Wong-Leung J. Jagadish C. 《Quantum Electronics, IEEE Journal of》2003,39(5):625-633
Thin p-clad InGaAs ridge waveguide quantum-well lasers having an asymmetric structure design were fabricated. The internal absorption coefficient is as low as 2.5 cm/sup -1/, due to the restricted field extension in the 0.3-/spl mu/m-thick p-type top AlGaAs cladding layer. Ti-Pt-Au metallization is used outside the ridge to provide adherence on the oxide while Au directly contacts the ridge region. It is shown that the most likely source of loss in these thin p-clad devices is scattering at the rough interface between Au and the p/sup ++/ top GaAs layer, after ohmic contact heat treatment. 相似文献
59.
SR Post LC Rump A Zambon RJ Hughes MD Buda JP Jacobson CC Kao PA Insel 《Canadian Metallurgical Quarterly》1998,273(36):23093-23097
60.
Molecular architecture and biophysical properties of phospholipids during thermal adaptation in fish: An experimental and model study 总被引:1,自引:0,他引:1
Elfrieda Fodor Richard H. Jones Csaba Buda Klara Kitajka Indranil Dey Tibor Farkas 《Lipids》1995,30(12):1119-1126
Phospholipids from livers of carps (Cyprinus carpio L.) adapted to winter (5°C) and summer (25°C) temperatures were isolated, and the fatty acid composition of total phospholipids,
as well as molecular species composition of diacyl phosphatidylcholines and ethanolamines, were determined. Order parameter
of 5-doxyl stearic acid and steady-state fluorescence anisotropy of different anthroyloxy fatty acids—[2-, 12(N-9-anthroyloxy)stearic acid and 16(N-9-anthroyloxy)palmitic acid—embedded in native and synthetic (16∶0/16∶0, 16∶0/22∶6, 18∶0/22∶6, 18∶1/22∶6, 20∶4/20∶4, 22∶6/22∶6
phosphatidylcholines and 16∶0/18∶1, 18∶1/22∶6 phosphatidylethanolamines) phospholipid vesicles was also determined between
−30 and 30°C and 5 and 30°C, respectively. There is an accumulation of 1-monoenoic, 2-polyenoic diacyl phosphatidylcholine
and ethanolamine with a concomitant reduction of 1-stearoyl,2-docosahexaenoyl species in the cold-adapted state. Despite a
30% accumulation of long-chain polyunsaturated fatty acids in phospholipids in cold, there is only a 5°C downshift in the
solid-gel to liquid-crystalline phase transition temperature (−8 vs. −13°C). Vesicles from total phospholipids of cold-adapted
fish proved to be more disordered in all segments than from the warmadapted ones when assayed using 2,12-(N-9-anthroyloxy)stearic and 16-(N-9-anthroyloxy)palmitic acid. Vesicles made from purified phosphatidylcholines showed the same pattern, but they were more
disordered than the corresponding total phospholipids. This could be modelled using mixed phospholipid vesicles made of synthetic
16∶0/22∶6 phosphatidylcholine (75%) and either 18∶1/22∶6 phosphatidylethanolamine (25%) vs. 16∶0/18∶1 phosphatidylethanolamine
(25%) and comparison of the anisotropy parameters of 100% 16∶0/22∶6 and 100% 18∶1/22∶6 phosphatidylcholine vesicles. Mixing
either 16∶0/18∶1 (25%) or 18∶1/22∶6 (25%) phosphatidylethanolamines to 18∶0/22∶6 (75%) phosphatidylcholine shifted down or
up, respectively, the transition temperature of vesicles compared to 100% 18∶0/22∶6 vesicles assayed by electron spin resonance
spectroscopy using 5-doxylstearic acid. It is concluded that it is not the gross amount of long-chain polyunsaturated fatty
acids in phospholipids, but rather their specific combination withcis Δ9 monounsaturated fatty acids in the positionsn-1, especially in phosphatidylethanolamines, that is important in determining the physical properties of biomembranes in relation
to adaptational temperature. 相似文献