282 research outputs found
Proton Irradiation Experiment for the X-ray Charge-Coupled Devices of the Monitor of All-sky X-ray Image mission onboard the International Space Station: I. Experimental Setup and Measurement of the Charge Transfer Inefficiency
We have investigated the radiation damage effects on a CCD to be employed in
the Japanese X-ray astronomy mission including the Monitor of All-sky X-ray
Image (MAXI) onboard the International Space Station (ISS). Since low energy
protons release their energy mainly at the charge transfer channel, resulting a
decrease of the charge transfer efficiency, we thus focused on the low energy
protons in our experiments. A 171 keV to 3.91 MeV proton beam was irradiated to
a given device. We measured the degradation of the charge transfer inefficiency
(CTI) as a function of incremental fluence. A 292 keV proton beam degraded the
CTI most seriously. Taking into account the proton energy dependence of the
CTI, we confirmed that the transfer channel has the lowest radiation tolerance.
We have also developed the different device architectures to reduce the
radiation damage in orbit. Among them, the ``notch'' CCD, in which the buried
channel implant concentration is increased, resulting in a deeper potential
well than outside, has three times higher radiation tolerance than that of the
normal CCD. We then estimated the charge transfer inefficiency of the CCD in
the orbit of ISS, considering the proton energy spectrum. The CTI value is
estimated to be 1.1e-5 per each transfer after two years of mission life in the
worse case analysis if the highest radiation-tolerant device is employed. This
value is well within the acceptable limit and we have confirmed the high
radiation-tolerance of CCDs for the MAXI mission.Comment: 17 pages, 2 table, 12 figures. Accepted for publication of Japanese
Journal of Applied Physics. High resolution file is available from
http://wwwxray.ess.sci.osaka-u.ac.jp/~miyata/paper/proton_cti.pd
Integrated pulmonary index can predict respiratory compromise in high-risk patients in the post-anesthesia care unit: a prospective, observational study
Background: Respiratory compromise (RC) including hypoxia and hypoventilation is likely to be missed in the postoperative period. Integrated pulmonary index (IPI) is a comprehensive respiratory parameter evaluating ventilation and oxygenation. It is calculated from four parameters: end-tidal carbon dioxide, respiratory rate, oxygen saturation measured by pulse oximetry (SpO(2)), and pulse rate. We hypothesized that IPI monitoring can help predict the occurrence of RC in patients at high-risk of hypoventilation in post-anesthesia care units (PACUs).
Methods: This prospective observational study was conducted in two centers and included older adults (>= 75-year-old) or obese (body mass index >= 28) patients who were at high-risk of hypoventilation. Monitoring was started on admission to the PACU after elective surgery under general anesthesia. We investigated the onset of RC defined as respiratory events with prolonged stay in the PACU or transfer to the intensive care units; airway narrowing, hypoxemia, hypercapnia, wheezing, apnea, and any other events that were judged to require interventions. We evaluated the relationship between several initial parameters in the PACU and the occurrence of RC. Additionally, we analyzed the relationship between IPI fluctuation during PACU stay and the occurrences of RC using individual standard deviations of the IPI every five minutes (IPI-SDs).
Results: In total, 288 patients were included (199 elderly, 66 obese, and 23 elderly and obese). Among them, 18 patients (6.3 %) developed RC. The initial IPI and SpO(2) values in the PACU in the RC group were significantly lower than those in the non-RC group (6.7 +/- 2.5 vs. 9.0 +/- 1.3, p
Conclusions: Our study showed that low value of the initial IPI and the fluctuating IPI after admission to the PACU predict the occurrence of RC. The IPI might be useful for respiratory monitoring in PACUs and ICUs after general anesthesia
Histidine-rich glycoprotein as a prognostic biomarker for sepsis
Various biomarkers have been proposed for sepsis; however, only a few become the standard. We previously reported that plasma histidine-rich glycoprotein (HRG) levels decreased in septic mice, and supplemental infusion of HRG improved survival in mice model of sepsis. Moreover, our previous clinical study demonstrated that HRG levels in septic patients were lower than those in noninfective systemic inflammatory response syndrome patients, and it could be a biomarker for sepsis. In this study, we focused on septic patients and assessed the differences in HRG levels between the non-survivors and survivors. We studied ICU patients newly diagnosed with sepsis. Blood samples were collected within 24 h of ICU admission, and HRG levels were determined using an enzyme-linked immunosorbent assay. Ninety-nine septic patients from 11 institutes in Japan were included. HRG levels were significantly lower in non-survivors (n=16) than in survivors (n=83) (median, 15.1 [interquartile ranges, 12.7-16.6] vs. 30.6 [22.1-39.6] mu g/ml; p<0.01). Survival analysis revealed that HRG levels were associated with mortality (hazard ratio 0.79, p<0.01), and the Harrell C-index (predictive power) for HRG was 0.90. These results suggested that HRG could be a novel prognostic biomarker for sepsis
Differing deregulation of HER2 in primary gastric cancer and synchronous related metastatic lymph nodes
Sorbtional properties of carbonic sorbents on the base of pine sawdust in the processes of purification of water mediums and complicated technological solution from petroleum products and phosphorus compounds are investigated. The possibility of carbonic sorbents modification by halogen organic compounds to increase the degree of purification of water ecosystems is analyzed. Исследованы сорбционные свойства углеродных сорбентов на основе опилок сосны в процессе очистки водных сред и сложных технологических растворов от нефтепродуктов и соединений фосфора. Рассмотрена возможность модифицирования углеродных сорбентов галогенсодержащих органическими соединениями с целью повыше-ния степени очистки водных экосистем. Досліджено сорбційні властивості вуглецевих сорбентів на основі обпилювань сосни у процесі очищення водних середовищ і складних технологічних розчинів від нафтопродуктів і з’єднань фосфору. Розглянуто можливість модифікування вуглецевих сорбентів галогеновмісними органічними з’єднаннями з метою підвищення ступеня очищення водних екосистем
MAXI GSC observations of a spectral state transition in the black hole candidate XTE J1752-223
We present the first results on the black hole candidate XTE J1752-223 from
the Gas Slit Camera (GSC) on-board the Monitor of All-sky X-ray Image (MAXI) on
the International Space Station. Including the onset of the outburst reported
by the Proportional Counter Array on-board the Rossi X-ray Timing Explorer on
2009 October 23, the MAXI/GSC has been monitoring this source approximately 10
times per day with a high sensitivity in the 2-20 keV band. XTE J1752-223 was
initially in the low/hard state during the first 3 months. An anti-correlated
behavior between the 2-4 keV and 4-20 keV bands were observed around January
20, 2010, indicating that the source exhibited the spectral transition to the
high/soft state. A transient radio jet may have been ejected when the source
was in the intermediate state where the spectrum was roughly explained by a
power-law with a photon index of 2.5-3.0. The unusually long period in the
initial low/hard state implies a slow variation in the mass accretion rate, and
the dramatic soft X-ray increase may be explained by a sudden appearance of the
accretion disk component with a relatively low innermost temperature (0.4-0.7
keV). Such a low temperature might suggest that the maximum accretion rate was
just above the critical gas evaporation rate required for the state transition.Comment: Publication of Astronomical Society of Japan Vol.62, No.5 (2010) [in
print
Bright X-ray flares from the BL Lac object Mrk 421, detected with MAXI in 2010 January and February
Strong X-ray flares from the blazar Mrk 421 were detected in 2010 January and
February through the 7 month monitoring with the MAXI GSC. The maximum 2 -- 10
keV flux in the January and February flares was measured as 120 +- 10 mCrab and
164 +- 17 mCrab respectively; the latter is the highest among those reported
from the object. A comparison of the MAXI and Swift BAT data suggests a convex
X-ray spectrum with an approximated photon index of about 2. This spectrum is
consistent with a picture that MAXI is observing near the synchrotron peak
frequency. The source exhibited a spectral variation during these flares,
slightly different from those in the previous observations, in which the
positive correlation between the flux and hardness was widely reported. By
equating the halving decay timescale in the January flare, s, to the synchrotron cooling time, the magnetic field was
evaluated as B = 0.045 G , where is the jet
beaming factor. Assuming that the light crossing time of the emission region is
shorter than the doubling rise time, s,
the region size was roughly estimated as cm
. These are consistent with the values previously reported. For
the February flare, the rise time, s, gives a
loose upper limit on the size as cm ,
although the longer decay time s, indicates
B = 0.015 G , which is weaker than the previous results.
This could be reconciled by invoking a scenario that this flare is a
superposition of unresolved events with a shorter timescale.Comment: 14 pages, 4 figures, accepted for PASJ (Vol. 62 No. 6
Internet use and problematic Internet use among adolescents in Japan: A nationwide representative survey
AbstractIntroductionJapan is assumed to have serious health and social problems due to Internet overuse, but little is known about the actual conditions. This study was conducted to investigate the prevalence of problematic Internet use (PIU) and associated Internet use in adolescents in Japan.MethodsA nationwide survey of adolescent Internet use was conducted in 2012 and 2013. The participants were 100,050 students from randomly selected junior and senior high schools nationwide who gave valid responses to a self-reported questionnaire. The questionnaire included questions on Internet use and the Japanese version of the Young's Diagnostic Questionnaire (YDQ) as well as other questions related to lifestyle habits. Internet users were classified by gender according to three categories on the basis of their YDQ scores: adaptive use, maladaptive use, and PIU.ResultsThe estimated prevalence of PIU was 6.2% in males, 9.8% in females, and 7.9% in total; it closely correlated with female gender, school grades, and number of Internet hours. The following common and gender-specific applications that conferred a risk of PIU were identified: downloading (both genders), online gaming (males), social networking services, blogs, and bulletin boards (females).ConclusionsA cross-sectional survey using YDQ of a large number of high school students yielded a PIU prevalence of 7.9% in Japan. This study showed that problems associated with Internet overuse have already become serious; therefore, planning and implementation of prevention and control measures is urgently required
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