482 research outputs found
Measurements of Proton, Helium and Muon Spectra at Small Atmospheric Depths with the BESS Spectrometer
The cosmic-ray proton, helium, and muon spectra at small atmospheric depths
of 4.5 -- 28 g/cm^2 were precisely measured during the slow descending period
of the BESS-2001 balloon flight. The variation of atmospheric secondary
particle fluxes as a function of atmospheric depth provides fundamental
information to study hadronic interactions of the primary cosmic rays with the
atmosphere.Comment: 21 pages, 11 figures, 4 table
Precise Measurements of Atmospheric Muon Fluxes with the BESS Spectrometer
The vertical absolute fluxes of atmospheric muons and muon charge ratio have
been measured precisely at different geomagnetic locations by using the BESS
spectrometer. The observations had been performed at sea level (30 m above sea
level) in Tsukuba, Japan, and at 360 m above sea level in Lynn Lake, Canada.
The vertical cutoff rigidities in Tsukuba (36.2 N, 140.1 E) and in Lynn Lake
(56.5 N, 101.0 W) are 11.4 GV and 0.4 GV, respectively. We have obtained
vertical fluxes of positive and negative muons in a momentum range from 0.6 to
20 GeV/c with systematic errors less than 3 % in both measurements. By
comparing the data collected at two different geomagnetic latitudes, we have
seen an effect of cutoff rigidity. The dependence on the atmospheric pressure
and temperature, and the solar modulation effect have been also clearly
observed. We also clearly observed the decrease of charge ratio of muons at low
momentum side with at higher cutoff rigidity region.Comment: 35 pages, 9 figures. Submitted to Astroparticle Physic
Measurement of Low-Energy Cosmic-Ray Antiprotons at Solar Minimum
The absolute fluxes of the cosmic-ray antiprotons at solar minimum are
measured in the energy range 0.18 to 1.4 GeV, based on 43 events unambiguously
detected in BESS '95 data. The resultant energy spectrum appears to be flat
below 1 GeV, compatible with a possible admixture of primary antiproton
component with a soft energy spectrum, while the possibility of secondary
antiprotons alone explaining the data cannot be excluded with the present
accuracy. Further improvement of statistical accuracy and extension of the
energy range are planned in future BESS flights.Comment: REVTeX, 4 pages including 4 eps figures. Submitted to PR
Precision Measurement of Cosmic-Ray Antiproton Spectrum
The energy spectrum of cosmic-ray antiprotons has been measured in the range
0.18 to 3.56 GeV, based on 458 antiprotons collected by BESS in recent
solar-minimum period. We have detected for the first time a distinctive peak at
2 GeV of antiprotons originating from cosmic-ray interactions with the
interstellar gas. The peak spectrum is reproduced by theoretical calculations,
implying that the propagation models are basically correct and that different
cosmic-ray species undergo a universal propagation. Future BESS flights toward
the solar maximum will help us to study the solar modulation and the
propagation in detail and to search for primary antiproton components.Comment: REVTeX, 4 pages including 4 eps figure
The oxytocin analogue carbetocin prevents emotional impairment and stress-induced reinstatement of opioid-seeking in morphine-abstinent mice.
The main challenge in treating opioid addicts is to maintain abstinence due to the affective consequences associated with withdrawal which may trigger relapse. Emerging evidence suggests a role of the neurohypophysial peptide oxytocin (OT) in the modulation of mood disorders as well as drug addiction. However, its involvement in the emotional consequences of drug abstinence remains unclear. We investigated the effect of 7-day opioid abstinence on the oxytocinergic system and assessed the effect of the OT analogue carbetocin (CBT) on the emotional consequences of opioid abstinence, as well as relapse. Male C57BL/6J mice were treated with a chronic escalating-dose morphine regimen (20-100 mg/kg/day, i.p.). Seven days withdrawal from this administration paradigm induced a decrease of hypothalamic OT levels and a concomitant increase of oxytocin receptor (OTR) binding in the lateral septum and amygdala. Although no physical withdrawal symptoms or alterations in the plasma corticosterone levels were observed after 7 days of abstinence, mice exhibited increased anxiety-like and depressive-like behaviors and impaired sociability. CBT (6.4 mg/kg, i.p.) attenuated the observed negative emotional consequences of opioid withdrawal. Furthermore, in the conditioned place preference paradigm with 10 mg/kg morphine conditioning, CBT (6.4 mg/kg, i.p.) was able to prevent the stress-induced reinstatement to morphine-seeking following extinction. Overall, our results suggest that alterations of the oxytocinergic system contribute to the mechanisms underlying anxiety, depression, and social deficits observed during opioid abstinence. This study also highlights the oxytocinergic system as a target for developing pharmacotherapy for the treatment of emotional impairment associated with abstinence and thereby prevention of relapse
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PEG−peptide conjugates
The remarkable diversity of the self-assembly behavior
of PEG−peptides is reviewed, including self-assemblies formed by PEG−peptides with β-sheet and α-helical (coiled-coil) peptide sequences. The modes of self-assembly in solution and in the solid state are discussed. Additionally, applications in bionanotechnology and synthetic materials science are summarized
Surface-Initiated Polymer Brushes in the Biomedical Field: Applications in Membrane Science, Biosensing, Cell Culture, Regenerative Medicine and Antibacterial Coatings
Relationships of the Duration from Onset and Macular Morphology with Metamorphopsia After Surgery for Macula-Off Rhegmatogenous Retinal Detachment
Tadanobu Sato,1 Tadamichi Akagi,1 Daigo Kobayashi,1 Akiko Anraku,2 Yohei Nozaki,1 Takumi Ando,1 Hiromitsu Yoshida,1 Hiroko Terashima,1 Hiruma Hasebe,2 Takeo Fukuchi1 1Division of Ophthalmology and Visual Science, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan; 2Department of Ophthalmology, Saiseikai Niigata Hospital, Niigata, JapanCorrespondence: Tadamichi Akagi, Division of Ophthalmology and Visual Science, Graduate School of Medical and Dental Sciences, Niigata University, 1-757, Asahimachi-dori, Chuo-ku, Niigata, 951-8510, Japan, Tel +81-25-227-2296, Fax: +81-25-227-0785, Email [email protected]: To investigate the relationships among postoperative metamorphopsia and postoperative macular morphological changes and the duration from the onset of visual field disturbance to surgery (DVD) in patients who underwent surgery for macula-off rhegmatogenous retinal detachment (RRD).Patients and Methods: We retrospectively reviewed 33 eyes of 33 patients who underwent pars plana vitrectomy (PPV) for macula-off RRD with known onset of symptoms of visual field disturbance at Niigata University Medical and Dental Hospital or Saiseikai Niigata Hospital and were followed up for at least 6 months postoperatively. Optical coherence tomography images of the macula obtained at 6 months postoperatively and DVD were analyzed, and the associations of the DVD with vertical metamorphopsia (vM) and horizontal metamorphopsia (hM) at 6 months postoperatively were evaluated using M-CHARTS.Results: vM was significantly correlated with the DVD and ellipsoid zone (EZ) disruption (P = 0.004 and P = 0.008, respectively), while hM was significantly correlated only with the DVD (P = 0.018). vM was significantly smaller in eyes with a DVD ≤ 7 days (0.34 ± 0.35)) than in eyes with a DVD ≥ 8 days (0.69 ± 0.32) (P = 0.005). In the multivariate analyses, postoperative vM was significantly associated with EZ disruption and the DVD (≤ 7 or ≥ 8 days) (P = 0.012 and P = 0.014, respectively).Conclusion: Metamorphopsia after PPV for macula off RRD was associated with the DVD and EZ disruption.Keywords: pars plana vitrectomy, optical coherence tomography, vision disorders, macula-off rhegmatogenous retinal detachmen
Cys34-cysteinylated human serum albumin is a sensitive plasma marker in oxidative stress-related chronic diseases
The degree of oxidized cysteine (Cys) 34 in human serum albumin (HSA), as determined by high performance liquid chromatography (HPLC), is correlated with oxidative stress related pathological conditions. In order to further characterize the oxidation of Cys34-HSA at the molecular level and to develop a suitable analytical method for a rapid and sensitive clinical laboratory analysis, the use of electrospray ionization time-of-flight mass spectrometer (ESI-TOFMS) was evaluated. A marked increase in the cysteinylation of Cys34 occurs in chronic liver and kidney diseases and diabetes mellitus. A significant positive correlation was observed between the Cys-Cys34-HSA fraction of plasma samples obtained from 229 patients, as determined by ESI-TOFMS, and the degree of oxidized Cys34-HSA determined by HPLC. The Cys-Cys34-HSA fraction was significantly increased with the progression of liver cirrhosis, and was reduced by branched chain amino acids (BCAA) treatment. The changes in the Cys-Cys34-HSA fraction were significantly correlated with the alternations of the plasma levels of advanced oxidized protein products, an oxidative stress marker for proteins. The binding ability of endogenous substances (bilirubin and tryptophan) and drugs (warfarin and diazepam) to HSA purified from chronic liver disease patients were significantly suppressed but significantly improved by BCAA supplementation. Interestingly, the changes in this physiological function of HSA in chronic liver disease were correlated with the Cys-Cys34-HSA fraction. In conclusion, ESI-TOFMS is a suitable high throughput method for the rapid and sensitive quantification of Cys-Cys34-HSA in a large number of samples for evaluating oxidative stress related chronic disease progression or in response to a treatment
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