130 research outputs found
Absorption of Horseradish Peroxidase (HRP) In Vitro Across Bovine Jejunal and Ileal Epithelia Around the Time of Weaning
Using the everted sac methodology as well as an Ussing chamber, we investigated changes in the absorption of horseradish peroxidase (EC 1.11.1.7, HRP (40 kDa)) in jejunum and ileum segments isolated from male Holstein cattle around the time of weaning (6 to 15 wks old). By the everted sac method, HRP transport (HRP concentration on the serosal side sampled after a 60-min-incubation) at 15 wks of age was significantly greater than that at 6 wks of age, in both segments of the intestine. Absorption was not significantly different between the jejunum and ileum. Addition of Na^+/K^+ ATPase inhibitor (ouabain, 1 mM) did not cause any significant change in HRP absorption, whereas Na^+/H^+ anti-transporter inhibitor (amiloride, 1μM) significantly increased the absorption in both sacs at 8 wks of age. By the Ussing chamber method, there were no significant differences between the values for Jsm and Jms, while the Jnet value was nearly zero for both epithelia. In addition, the flux (Jms) of Lucifer yellow, a cell-membrane-impermeable fluorescence dye, was significantly greater at 6 than at 13 wks of age in the ileal epithelia, although the flux was significantly greater in the jejunal than the ileal epithelia at both ages. From these findings, we conclude that: 1) bovine jejunal and ileal epithelia are able to absorb a large molecule such as the HRP protein; 2) HRP transport occurs in a concentration-dependent manner and may in part be via a paracellular pathway; 3) the increased HRP transport shown at 15 wks of age may not be caused by an increased use of the paracellular pathway.horseradish peroxidaseabsorptiontransportcal
Sensorimotor Modulation Differs with Load Type during Constant Finger Force or Position
During submaximal isometric contraction, there are two different load types: production of a constant force against a rigid restraint (force task), and maintenance of position against a constant load (position task). Previous studies reported that the time to task failure during a fatigue task was twice as long in the force task compared with the position task. Sensory feedback processing may contribute to these differences. The purpose of the current study was to determine the influence of load types during static muscle contraction tasks on the gating effect, i.e., attenuation of somatosensory-evoked potentials (SEPs) and the cortical silent period (cSP). Ten healthy subjects contracted their right first dorsal interosseus muscle by abducting their index finger for 90 s, to produce a constant force against a rigid restraint that was 20% of the maximum voluntary contraction (force task), or to maintain a constant position with 10° abduction of the metacarpophalangeal joint against the same load (position task). Somatosensory evoked potentials (SEPs) were recorded from C3′ by stimulating either the right ulnar or median nerve at the wrist while maintaining contraction. The cortical silent period (cSP) was also elicited by transcranial magnetic stimulation. Reduction of the amplitude of the P45 component of SEPs was significantly larger during the position task than during the force task and under control rest conditions when the ulnar nerve, but not the median nerve, was stimulated. The position task had a significantly shorter cSP duration than the force task. These results suggest the need for more proprioceptive information during the position task than the force task. The shorter duration of the cSP during the position task may be attributable to larger amplitude of heteronymous short latency reflexes. Sensorimotor modulations may differ with load type during constant finger force or position tasks.This work was supported by a Grant-in-Aid for Scientific Research (C) No. 08042773 from the Japan Society for the Promotion of Science (JSPS) (http://www.jsps.go.jp/english/e-grants/index.html) and a Research Grant from Niigata University of Health and Welfare (NUHW) (http://www.nuhw.ac.jp/e/). HK received both grants. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Impact of Full Prelithiation of Si-Based Anodes on the Rate and Cycle Performance of Li-Ion Capacitors
The impact of full prelithiation on the rate and cycle performance of a Si-based Li-ion capacitor (LIC) was investigated. Full prelithiation of the anode was achieved by assembling a half cell with a 2 mu m-sized Si anode (0 V vs. Li/Li+) and Li metal. A three-electrode full cell (100% prelithiation) was assembled using an activated carbon (AC) cathode with a high specific surface area (3041 m(2)/g), fully prelithiated Si anode, and Li metal reference electrode. A three-electrode full cell (87% prelithiation) using a Si anode prelithiated with 87% Li ions was also assembled. Both cells displayed similar energy density levels at a lower power density (200 Wh/kg at <= 100 W/kg; based on the total mass of AC and Si). However, at a higher power density (1 kW/kg), the 100% prelithiation cell maintained a high energy density (180 Wh/kg), whereas that of the 87% prelithiation cell was significantly reduced (80 Wh/kg). During charge/discharge cycling at similar to 1 kW/kg, the energy density retention of the 100% prelithiation cell was higher than that of the 87% prelithiation cell. The larger irreversibility of the Si anode during the initial Li-ion uptake/release cycles confirmed that the simple full prelithiation process is essential for Si-based LIC cells
Refinement of Conditions of Point-Contact Current Imaging Atomic Force Microscopy for Molecular-Scale Conduction Measurements
A walking support/evaluation machine for patients with parkinsonism
Various walk supporting systems have been devised and developed. However, they have not been designed for supporting or evaluating the gait of parkinsonian patients, and not much consideration has been given to gait disturbances of parkinsonian patients. In this study : (a) We prepared a tentative model of walk supporting and monitoring system in consideration of typical symptoms of parkinsonism. (b) We conducted gait rehabilitation in a parkinsonian patient using the walk supporting and monitoring system and confirmed (i) the occurrence of frozen gait during walking, (ii) brachybasia, (iii) the absence of anterior tilting of the posture, pulsion symptom, and festination, and (iv) occurrence of hesitation to start walking. Therefore, typical symptoms of parkinsonism can be detected by the use of this system. (c) The medical staff can evaluate the state of recovery of patients on the basis of the data obtained from this system and use them for purposes such as guidance of rehabilitation
Evaluation of the Pichia pastoris expression system for the production of GPCRs for structural analysis
<p>Abstract</p> <p>Background</p> <p>Various protein expression systems, such as <it>Escherichia coli </it>(<it>E. coli</it>), <it>Saccharomyces cerevisiae </it>(<it>S. cerevisiae</it>), <it>Pichia pastoris </it>(<it>P. pastoris</it>), insect cells and mammalian cell lines, have been developed for the synthesis of G protein-coupled receptors (GPCRs) for structural studies. Recently, the crystal structures of four recombinant human GPCRs, namely β<sub>2 </sub>adrenergic receptor, adenosine A<sub>2a </sub>receptor, CXCR4 and dopamine D3 receptor, were successfully determined using an insect cell expression system. GPCRs expressed in insect cells are believed to undergo mammalian-like posttranscriptional modifications and have similar functional properties than in mammals. Crystal structures of GPCRs have not yet been solved using yeast expression systems. In the present study, <it>P. pastoris </it>and insect cell expression systems for the human muscarinic acetylcholine receptor M2 subtype (CHRM2) were developed and the quantity and quality of CHRM2 synthesized by both expression systems were compared for the application in structural studies.</p> <p>Results</p> <p>The ideal conditions for the expression of CHRM2 in <it>P. pastoris </it>were 60 hr at 20°C in a buffer of pH 7.0. The specific activity of the expressed CHRM2 was 28.9 pmol/mg of membrane protein as determined by binding assays using [<sup>3</sup>H]-quinuclidinyl benzilate (QNB). Although the specific activity of the protein produced by <it>P. pastoris </it>was lower than that of Sf9 insect cells, CHRM2 yield in <it>P. pastoris </it>was 2-fold higher than in Sf9 insect cells because <it>P. pastoris </it>was cultured at high cell density. The dissociation constant (Kd) for QNB in <it>P. pastoris </it>was 101.14 ± 15.07 pM, which was similar to that in Sf9 insect cells (86.23 ± 8.57 pM). There were no differences in the binding affinity of CHRM2 for QNB between <it>P. pastoris </it>and Sf9 insect cells.</p> <p>Conclusion</p> <p>Compared to insect cells, <it>P. pastoris </it>is easier to handle, can be grown at lower cost, and can be expressed quicker at a large scale. Yeast, <it>P. pastoris</it>, and insect cells are all effective expression systems for GPCRs. The results of the present study strongly suggested that protein expression in <it>P. pastoris </it>can be applied to the structural and biochemical studies of GPCRs.</p
Real-time measurement of frozen gait in patient with parkinsonism using a sensor-controlled walker
Patients with Parkinson’s disease develop gait disturbances. Although the use of walkers is very effective for maintaining locomotive ability, patients who have symptoms such as frozen gait (FG) and festinating gait may fall even with a walker equipped with a brake as they cannot use the brake well in an emergency and fail to follow the accelerating walker. None of the studies on walking aids to date have addressed real-time detection of FG or the use of this information for the control of the walking aid, monitoring of the state of improvement in the ambulatory function, or evaluation of the effect of the use of a walker. In this study, we evaluated whether the state called FG, a characteristic symptom of Parkinson’s disease, can be detected by the use of a sensor-controlled walker with heel-to-toe pressure sensors. The following two measurements were carried out in one male healthy and a one male patient with stage 3 Parkinson’s disease by the Hoehn-Yahr scale showing mild muscle rigidity, hypokinesia, and FG. In the healthy subject, the heel-to-toe pressure showed smooth heel-to-toe shifts during the standing phase. In the patient with Parkinson’s disease, the heel-to-toe response time was about 2.4 times longer than in the healthy subject at the beginning of walking, and FG could be recorded as the difficulty in lifting the foot by the toes. Also, when FG was observed during walking, the pressure waves recorded by the same sensors showed two peaks occurring at a short interval, indicating double landings
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Chemical Bonding, Interfaces and Defects in Hafnium Oxide/Germanium Oxynitride Gate Stacks on Ge (100)
Correlations among interface properties and chemical bonding characteristics in HfO{sub 2}/GeO{sub x}N{sub y}/Ge MIS stacks were investigated using in-situ remote nitridation of the Ge (100) surface prior to HfO{sub 2} atomic layer deposition (ALD). Ultra thin ({approx}1.1 nm), thermally stable and aqueous etch-resistant GeO{sub x}N{sub y} interfaces layers that exhibited Ge core level photoelectron spectra (PES) similar to stoichiometric Ge{sub 3}N{sub 4} were synthesized. To evaluate GeO{sub x}N{sub y}/Ge interface defects, the density of interface states (D{sub it}) was extracted by the conductance method across the band gap. Forming gas annealed (FGA) samples exhibited substantially lower D{sub it} ({approx} 1 x 10{sup 12} cm{sup -2} eV{sup -1}) than did high vacuum annealed (HVA) and inert gas anneal (IGA) samples ({approx} 1x 10{sup 13} cm{sup -2} eV{sup -1}). Germanium core level photoelectron spectra from similar FGA-treated samples detected out-diffusion of germanium oxide to the HfO{sub 2} film surface and apparent modification of chemical bonding at the GeO{sub x}N{sub y}/Ge interface, which is related to the reduced D{sub it}
The ASTRO-H X-ray Observatory
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly
successful X-ray missions initiated by the Institute of Space and Astronautical
Science (ISAS). ASTRO-H will investigate the physics of the high-energy
universe via a suite of four instruments, covering a very wide energy range,
from 0.3 keV to 600 keV. These instruments include a high-resolution,
high-throughput spectrometer sensitive over 0.3-2 keV with high spectral
resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in
the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers
covering 5-80 keV, located in the focal plane of multilayer-coated, focusing
hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12
keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and
a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the
40-600 keV band. The simultaneous broad bandpass, coupled with high spectral
resolution, will enable the pursuit of a wide variety of important science
themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical
Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to
Gamma Ray
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