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21.
Feeding Responses of Free-flying Honeybees to Secondary Compounds Mimicking Floral Nectars 总被引:1,自引:0,他引:1
The role of secondary compounds (SC) in deterring herbivores and pathogens from vegetative parts of plants is well established,
whereas their role in plant reproductive organs such as floral nectar is unclear. The present study aimed to reveal the response
of free-flying honeybees to naturally occurring concentrations of four SC in floral nectar. We selected nicotine, anabasine,
caffeine, and amygdalin, all of which are found in nectar of various plants. In repeated paired-choice experiments, we offered
20% sucrose solution as control along with test solutions of 20% sucrose with various concentrations of the above SC. Except
for anabasine, naturally occurring concentrations of SC did not have a deterring effect. Furthermore, low concentrations of
nicotine and caffeine elicited a significant feeding preference. SC can, therefore, be regarded as postingestive stimulants
to pollinators, indicating that the psychoactive alkaloids in nectar may be a part of their mutualistic reward. Further studies
are needed to test our hypothesis that psychoactive alkaloids in nectar impose dependence or addiction effects on pollinators. 相似文献
22.
23.
The effect of radio-frequency (RF) or low-frequency (LF) bias voltage on the for- mation of amorphous hydrogenated carbon (a-C:H) films was studied on silicon substrates with a low methane (CH4) concentration (2-10 vol.%) in CH4+Ar mixtures. The bias substrate was applied either by RF (13.56 MHz) or by LF (150 kHz) power supply. The highest hardness values (~18-22 GPa) with lower hydrogen content in the fihns (~20 at.%) deposited at 10 vol.% CH4, was achieved by using the RF bias, However, the films deposited using the LF bias, under similar RF plasma generation power and CH4 concentration (50 W and 10 vol.%, respectively), displayed lower hardness (~6-12 GPa) with high hydrogen content (~40 at.%). The structures analyzed by Fourier Transform Infrared (FTIR) and Raman scattering measurements provide an indication of trans-polyacetylene structure formation. However, its excessive formation in the films deposited by the LF bias method is consistent with its higher bonded hydrogen concentration and low level of hardness, as compared to the film prepared by the RF bias method. It was found that the effect of RF bias on the film structure and properties is stronger than the effect of the low-frequency (LF) bias under identical radio-frequency (RF) powered electrode and identical PECVD (plasma enhanced chemical vapor deposition) system configuration. 相似文献
24.
Nishiura M Nagasaka T Fujioka K Fujimoto Y Tanaka T Ido T Yamamoto S Kashiwa S Sasao M 《The Review of scientific instruments》2010,81(10):10D313
We developed a lost alpha detection system to use in burning plasma experiments. The scintillators of Ag:ZnS and polycrystalline Ce:YAG were designed for a high-temperature environment, and the optical transmission line was designed to transmit from the scintillator to the port plug. The required optical components of lenses and mirrors were irradiated using the fission reactor with the initial result that there was no clear change after the irradiation with a neutron flux of 9.6×10(17)?nm(-2) s(-1) for 48 h. We propose a diagnostic of alpha particle loss, so-called alpha particle induced gamma ray spectroscopy. The initial laboratory test has been carried out by the use of the Ce doped Lu(2)SiO(5) scintillator detector and an Am-Be source to detect the 4.44 MeV high energy gamma ray due to the (9)Be(α,nγ)(12)C reaction. 相似文献
25.
Shimizu A Ido T Nakamura S Toi K Nishiura M Kato S 《The Review of scientific instruments》2010,81(10):10E138
The heavy ion beam probe system in the Large Helical Device (LHD) was improved as follows. At first, the additional new sweeper was installed into the diagnostic port to extend the observable region. By using this sweeper, the potential profile was measured in a wider minor radius range than in previous experiments, in the case of outward shifted magnetic configuration of LHD. Next, the real time control system was installed to control the probe beam orbit for measuring the potential in plasma with large plasma current. In this system, a digital signal processor was used to control the probe beam in real time. The system worked well in the fixed position observation mode. In the sweeping mode for profile measurement, this control system became unstable. The details of this system and the experimental results are reported in this article. 相似文献
26.
Noam Ben-Eliezer Eddy Solomon Elad Harel Nava Nevo Lucio Frydman 《Magma (New York, N.Y.)》2012,25(6):433-442
Object
An approach has been recently introduced for acquiring arbitrary 2D NMR spectra or images in a single scan, based on the use of frequency-swept RF pulses for the sequential excitation and acquisition of the spins response. This spatiotemporal-encoding (SPEN) approach enables a unique, voxel-by-voxel refocusing of all frequency shifts in the sample, for all instants throughout the data acquisition. The present study investigates the use of this full-refocusing aspect of SPEN-based imaging in the multi-shot MRI of objects, subject to sizable field inhomogeneities that complicate conventional imaging approaches.Materials and methods
2D MRI experiments were performed at 7 T on phantoms and on mice in vivo, focusing on imaging in proximity to metallic objects. Fully refocused SPEN-based spin echo imaging sequences were implemented, using both Cartesian and back-projection trajectories, and compared with k-space encoded spin echo imaging schemes collected on identical samples under equal bandwidths and acquisition timing conditions.Results
In all cases assayed, the fully refocused spatiotemporally encoded experiments evidenced a ca. 50?% reduction in signal dephasing in the proximity of the metal, as compared to analogous results stemming from the k-space encoded spin echo counterparts.Conclusion
The results in this study suggest that SPEN-based acquisition schemes carry the potential to overcome strong field inhomogeneities, of the kind that currently preclude high-field, high-resolution tissue characterizations in the neighborhood of metallic implants. 相似文献27.
Akihiro Nishiguchi Fumisato Sasaki Hidehito Maeda Masayuki Kabayama Akio Ido Tetsushi Taguchi 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(35)
Endoscopic submucosal dissection (ESD) provides strong therapeutic benefits for early gastrointestinal cancer as a minimally invasive treatment. However, there is currently no reliable treatment to prevent scar contracture resulting from ESD which may lead to cicatricial stricture. Herein, a multifunctional colloidal wound dressing to promote tissue regeneration after ESD is demonstrated. This sprayable wound dressing, composed of hydrophobized microparticles, exhibits the multifunctionality necessary for wound healing including tissue adhesiveness, blood coagulation, re‐epithelialization, angiogenesis, and controlled inflammation based on hydrophobic interaction with biological systems. An in vivo feasibility study using swine gastric ESD models reveals that this colloidal wound dressing suppresses fibrosis and accelerates wound healing. Multifunctional colloidal and sprayable wound dressings have an enormous therapeutic potential for use in a wide range of biomedical applications including accelerated wound healing after ESD, prevention of perforation, and the treatment of inflammatory diseases. 相似文献
28.
Ben-Eliezer E Marom E 《Journal of the Optical Society of America. A, Optics, image science, and vision》2007,24(4):1003-1010
We present an approach that provides superresolution beyond the classical limit as well as image restoration in the presence of aberrations; in particular, the ability to obtain superresolution while extending the depth of field (DOF) simultaneously is tested experimentally. It is based on an approach, recently proposed, shown to increase the resolution significantly for in-focus images by speckle encoding and decoding. In our approach, an object multiplied by a fine binary speckle pattern may be located anywhere along an extended DOF region. Since the exact magnification is not known in the presence of defocus aberration, the acquired low-resolution image is electronically processed via a parallel-branch decoding scheme, where in each branch the image is multiplied by the same high-resolution synchronized time-varying binary speckle but with different magnification. Finally, a hard-decision algorithm chooses the branch that provides the highest-resolution output image, thus achieving insensitivity to aberrations as well as DOF variations. Simulation as well as experimental results are presented, exhibiting significant resolution improvement factors. 相似文献
29.
Maya Bar-Dolev Yeliz Celik J. S. Wettlaufer Peter L. Davies Ido Braslavsky 《Journal of the Royal Society Interface》2012,9(77):3249-3259
Antifreeze proteins (AFPs) evolved in many organisms, allowing them to survive in cold climates by controlling ice crystal growth. The specific interactions of AFPs with ice determine their potential applications in agriculture, food preservation and medicine. AFPs control the shapes of ice crystals in a manner characteristic of the particular AFP type. Moderately active AFPs cause the formation of elongated bipyramidal crystals, often with seemingly defined facets, while hyperactive AFPs produce more varied crystal shapes. These different morphologies are generally considered to be growth shapes. In a series of bright light and fluorescent microscopy observations of ice crystals in solutions containing different AFPs, we show that crystal shaping also occurs during melting. In particular, the characteristic ice shapes observed in solutions of most hyperactive AFPs are formed during melting. We relate these findings to the affinities of the hyperactive AFPs for the basal plane of ice. Our results demonstrate the relation between basal plane affinity and hyperactivity and show a clear difference in the ice-shaping mechanisms of most moderate and hyperactive AFPs. This study provides key aspects associated with the identification of hyperactive AFPs. 相似文献
30.
N. Momono T. Kurosawa Y. Amakai Y. Sato T. Suzuki H. Takano S. Murayama A. Sakai M. Oda M. Ido 《Journal of Superconductivity and Novel Magnetism》2010,23(5):785-787
The Raman scattering experiments were carried out in Zn-doped and Zn-free Bi2Sr2CaCu2O8+y
with optimal hole concentration below and above T
c
. The energy of pair-breaking peak in the B
1g
Raman spectrum, corresponding to the magnitude of superconducting gap 2Δ
0, is suppressed by 1% Zn-doping. In the normal state, the B
1g
Raman spectrum for Zn-doped sample shows no pseudogap behaviour, suggesting that the pseudogap is strongly smeared by Zn-doping. 相似文献