Search for Dark Photon Dark Matter in the Mass Range 74-110 µeV with a Cryogenic Millimeter-Wave Receiver.

We search for the dark photon dark matter (DPDM) using a cryogenic millimeter-wave receiver. DPDM has a kinetic coupling with electromagnetic fields with a coupling constant of χ and is converted into ordinary photons at the surface of a metal plate. We search for signal of this conversion in the frequency range 18-26.5 GHz, which corresponds to the mass range 74-110 µeV/c^{2}. We observed no significant signal excess, allowing us to set an upper bound of χ<(0.3-2.0)×10^{-10} at 95% confidence level. This is the most stringent constraint to date and tighter than cosmological constraints. Improvements from previous studies are obtained by employing a cryogenic optical path and a fast spectrometer.

The relationship between central motor conduction time and spinal cord compression in patients with cervical spondylotic myelopathy.

STUDY DESIGN: Retrospective study. OBJECTIVES: Few studies have reported a relationship between central motor conduction time (CMCT), which evaluates corticospinal function, and degree of spinal cord compression in patients with myelopathy. Thus, there is no consensus on predicting the degree of prolonged CMCT on the basis of the degree of spinal cord compression. If a correlation exists between CMCT and spinal cord compression, then spinal cord compression may be a useful noninvasive clinical indicator of corticospinal function. Therefore, this study evaluated the relationship between CMCT and cervical spinal cord compression measured by magnetic resonance imaging (MRI) in patients with cervical spondylotic myelopathy (CSM). SETTING: Hiroshima University Hospital in Japan. METHODS: We studied 33 patients undergoing laminoplasty. Patients exhibited significant cervical spinal cord compression on both MRI and intraoperative electrophysiological examination. We assessed transcranial magnetic stimulation measurement of CMCT; spinal cord compression parameters such as area, lateral diameter, anteroposterior diameter and flattening of the spinal cord at the lesion site and C2/3 levels on MRI; and pre- versus postoperative Japanese Orthopaedic Association (JOA) scores. RESULTS: Correlations between CMCT and flattening as well as anteroposterior diameter of the spinal cord at the lesion level were observed. Strong correlations between CMCT and the ratio of the flattening and anteroposterior diameter parameters at the lesion level to that at the C2/3 level were also observed. CONCLUSIONS: Measurement of spinal cord compression may be useful for the evaluation of corticospinal function as a proxy for CMCT in patients with CSM.

A novel subtype of G-protein-coupled receptor kinase, GRK7, in teleost cone photoreceptors.

Two kinds of retinal cDNA fragments (OIGRK-R and -C) encoding the putative G-protein-coupled receptor kinases (GRKs) were isolated from medaka, Oryzias latipes. OIGRK-R appears to be closely related to the rhodopsin kinase (RK) found in the outer segments of mammalian photoreceptors, but the deduced amino acid sequence of OIGRK-C shows less than 50% identity to those of GRKs known to date, suggesting that OIGRK-C is a novel GRK subtype (GRK7). The mRNA of OIGRK-R is detectable in rods, and that of OIGRK-C is found in all four types of cone photoreceptor. The C-terminal of OIGRK-R has a consensus sequence for farnesylation, whereas, surprisingly, OIGRK-C has a consensus sequence for geranylgeranylation. Our result are consistent with the concept that lower vertebrates have rod- and cone-specific opsin kinases.

The influence of eye movements and tactile information on postural sway in patients with peripheral vestibular lesions.

The statokinesigram of the 16 benign paroxysmal positional vertigo (BPPV) patients and the 28 vestibular deficits (VDS) patients were analyzed in comparison with the 20 normal subjects (NS). Velocity of the track (LNG/T), root mean square (RMS), and standard deviation area (SD-Area) were used as parameters. Fourteen different tests were done. When the result for each subject group were analyzed there were interesting differences between the compensated VDS and BPPV patients and between the untreated period and the compensated stage in each patient group. Comparing the data between NS and BPPV at the compensated stage, the latter group was unstable while watching LED with OKN on the tactile information plate (S-G plate). The significant differences were for RMS and SD-Area. The data of the NS and the untreated VDS show that the latter group was more unstable while watching LED with OKN than in the dark on the S-G plate. According to the data of the NS and the VDS at the compensated stage, the latter group was more unstable during OKN or watching LED which was almost the same as in the dark on both plate conditions. And it was more unstable while watching LED than during OKN on the S-G plate. The significant differences were for velocity of body sway (LNG/T). The neural region for compensation in BPPV patients might be on the visuo-oculomotor pathway through the peripheral retina. One of the most important regions for compensation in VDS patients might be in the rombencephalic reticular formation.

[Somatosensory-visual-vestibular interaction in a case of vermis agenesis].

It is well known that the somatosensory input is important for keep a balance as well as the visual and the vestibular inputs. However the knowledge of somatosensory-visual-vestibular interaction is incomplete at now. We have already made a mathematical model of these interactions by extension of the Raphan-Cohen model (Raphan et al, 1979) for visual-vestibular interaction with a direct and an indirect somatosensory pathway. This indirect somatosensory pathway has access to the common visual-vestibular velocity storage integrative mechanism. So the purpose of the present experiment was to verify whether such an extended model (Fig. 4) can be used to describe the nystagmus due to stimulation of the sensory system apart or in combination in case of vermis agenesis with Dandy-Walker's cyst. It was checked, on the other hand, where the lesion are extended. And moreover it was suspected that each parts of the mathematical model are compared with any central neural regions. As a result, the indirect pathways of visual, vestibular and somatosensory inputs and the direct pathways of visual and somatosensory inputs were disturbed completely. The disturbance of the indirect pathways was caused by lesion in the velocity storage integrator which was though to be included in the vestibular nuclei in monkey. The lesion in epsilon 3-h2 was suspected to explain a blockage of the direct visual pathway, and a disturbance of the direct somatosensory pathway was suspected the lesion in gs. We could explain this cause by a mathematical model for somatosensory-visual-vestibular interaction, so we could conclude that this model was useful for human beings as well as monkey.(ABSTRACT TRUNCATED AT 250 WORDS)

Some observations on the bleaching of ethylenediaminetetraacetic acid on green barley leaves.

Green barley leaves (Hordeum vulgaris) floated on the surface of 0.05 m ethylenediamine disodium tetraacetate, EDTA-2Na, pH 7.0 and exposed to light (5000 lux) at 25 degrees exhibited a marked bleaching (EDTA-bleaching) visible to the naked eye and paralleled by a striking reduction in content of chlorophylls a and b. This loss of color did not occur in controls which were treated with H(2)O instead of EDTA (water controls). In darkness the leaves in the water controls were bleached while EDTA-treated leaves retained all their color.EDTA bleaching was observed only in intact leaves. When leaves were boiled EDTA protected their pigment against photodecomposition. Without EDTA boiled leaves were bleached completely in light. When intact green leaves which had been floated on water and exposed to light for 48 hr were treated with boiling ethanol or acetone, the chlorophylls extracted by this procedure did not undergo bleaching if EDTA were present in solution. Under these conditions a green fine grain precipitate formed which was insoluble in ethanol or acetone and was stable in light or darkness.EDTA bleaching of green barley leaves was inhibited by KCN, and by the addition of casein hydrolysate.