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81.
Fluorine was introduced into the 2-position of the side chain of abscisic acid (ABA) analogues by Wittig reaction of alpha-ionone derivatives with ethyl triethylphosphono-2-fluoroacetate. The effects of the fluorinated analogues were evaluated on inhibition of cress seed germination and inhibition of gibberellin-inducible alpha-amylase induction in embryoless barley half-seeds. (2E, 4E)-2-Fluoro-5-(1'-hydroxy-2',6', 6'-trimethyl-2'-cyclohexen-1'-yl)-3-methyl-2,4-pentadienoic acid (5b) showed potent inhibitory activity at the same level as ABA in the cress seed germination test, and 5b also inhibited gibberellin-inducible alpha-amylase induction at 4 x 10(-)(6), 3 times the concentration of ABA (1 x 10(-)(6)) for 50% inhibition of alpha-amylase production. 5b also showed dehydrin induction activity. These results indicate that fluorinated ABA analogues mimic ABA action and can be a lead for a plant growth regulator which regulates plant growth or protects plants from environmental stresses.  相似文献   
82.
The cerebellar flocculus has been implicated in vestibulo-oculomotor control. One major central input to this structure originates from brainstem cells in the paramedian tract (PMT), whose function is unknown. Here it is reported that PMT cells in the pons carry vestibular and eye movement signals and their pharmacological inactivation produces a leaky integrator combined with vestibular imbalance. The results suggest that PMT cells provide the cerebellum with sensory and motor signals that are essential for velocity-to-position integration, a common premotor process that is required in all motor systems.  相似文献   
83.
The nature of the pseudogap phase of cuprate high-temperature superconductors is a major unsolved problem in condensed matter physics. We studied the commencement of the pseudogap state at temperature T* using three different techniques (angle-resolved photoemission spectroscopy, polar Kerr effect, and time-resolved reflectivity) on the same optimally doped Bi2201 crystals. We observed the coincident, abrupt onset at T* of a particle-hole asymmetric antinodal gap in the electronic spectrum, a Kerr rotation in the reflected light polarization, and a change in the ultrafast relaxational dynamics, consistent with a phase transition. Upon further cooling, spectroscopic signatures of superconductivity begin to grow close to the superconducting transition temperature (T(c)), entangled in an energy-momentum-dependent manner with the preexisting pseudogap features, ushering in a ground state with coexisting orders.  相似文献   
84.
The first stars fundamentally transformed the early universe by emitting the first light and by producing the first heavy elements. These effects were predetermined by the mass distribution of the first stars, which is thought to have been fixed by a complex interplay of gas accretion and protostellar radiation. We performed radiation-hydrodynamics simulations that followed the growth of a primordial protostar through to the early stages as a star with thermonuclear burning. The circumstellar accretion disk was evaporated by ultraviolet radiation from the star when its mass was 43 times that of the Sun. Such massive primordial stars, in contrast to the often-postulated extremely massive stars, may help explain the fact that there are no signatures of the pair-instability supernovae in abundance patterns of metal-poor stars in our galaxy.  相似文献   
85.
Coding assignments of genome segments 1 and 2 of Chuzan virus strain K-47 were studied in vitro by using rabbit reticulocyte lysates. The double-stranded RNA segment was extracted from sodium dodecyl sulfate (SDS)-polyacrylamide gels by a modified crushing and eluting technique. Translation products labeled with [35S]methionine were resolved by SDS-polyacrylamide gel electrophoresis. The molecular weights of the products from RNA segments 1 and 2 were estimated to be 98 and 95 kilodaltons, respectively.  相似文献   
86.
Diagnostic significance of electrophoretic findings of serum protein in cows with traumatic pericarditis was evaluated. Affected cows were classified into 3 groups according to autoptical findings: fibrinous, sero-fibrinous, and purulent types. Slight hypoprotenemia, moderate hypo-albuminemia, slight hyper-alpha globulinemia and tendency of hyper-beta globulinemia were commonly observed in the affected cows. The level of gamma globulin tended to be lower in the cows with fibrinous or sero-fibrinous, and higher in purulent pericarditis, than the level in healthy cows. In the serum protein electropherograms of the cows with fibrinous or sero-fibrinous pericarditis, there was pathognostic pattern composed of slender albumin, acute shape of alpha globulin with a broad rising accompanied by double peaks and with main peak migrating toward the albumin side, tendency of rising beta globulin fraction, and large indentation between beta and gamma fractions. These findings except for the slender albumin fraction, however, was not or poorly observed in purulent pericarditis. Electrophoretic findings were subacute inflammatory pattern with non-selective serum protein losing in fibrinous or sero-fibrinous, and chronic inflammatory pattern in purulent pericarditis.  相似文献   
87.
A newly identified aspermia rat mutant was investigated on testicular histology and mode of inheritance of the defect. Average testis weight of mutants was about one-third of that of phenotypically normal males. Spermatogenesis was interrupted at meiosis. Pachytene spermatocytes significantly decreased in number. Secondary spermatocytes and few round spermatids were seen, but no elongated spermatids and sperms were observed. A large basophilic inclusion-like body existed in the cytoplasm of late pachytene spermatocytes. Genetic analysis revealed an autosomal recessive transmission of the defect. Aspermia (As) was designated for the locus.  相似文献   
88.
Urbanization is expanding in and around small to medium-sized cities as well as in large cities, and the expansion includes low-lying areas where the flood risk is high. Flood risk in small watersheds has been evaluated using precise mathematical models. However, these models cannot be applied to larger basins due to the complexity of data collection and analysis. As a result, quantitative evaluations of flood risk at macro scales and the flood-prevention function of paddies around urban areas have not been made. This paper proposes a method and an index that can be used to evaluate the flood-prevention function of paddies on a regional scale. In addition, the use of this system for basin-wide management is illustrated by an example for the Kinu and Kokai rivers, which are tributaries of the Tone River of Japan. The applicability of the approach is evaluated using data from a major flood that occurred in the study area.  相似文献   
89.
The relative effect of light in inducing downward movements of the tips of isolated arms of Asterias amurensis is maximal at 485 millimicrons when the compound ocellus is intact; at 504 millimicrons when the ocellus has been removed. This finding suggests the coexistence of two photoreceptive systems, ocellar and nonocellar.  相似文献   
90.
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