Soft X-ray resonant Kerr rotation measurement and simulation of element-resolved and interface-sensitive magnetization reversals in a NiFe/FeMn/Co trilayer structure

We report experimental observations of element- and buried interface-resolved magnetization reversals in an oppositely exchange-biased NiFeFeMnCo trilayer structure by soft x-ray resonant Kerr rotation measurements. Not only Co-, Ni-, Fe-specific exchange-biased loops but also interfacial uncompensated (UC) Fe reversal loops coupled to the individual Co and NiFe layers are separately observed. From the experimental results interpreted with the help of the model simulations of soft x-ray resonant Kerr rotation, the effective thicknesses of interfacial UC regions at the buried interfaces of both FeMnCo and NiFeFeMn are found to be tUC =13??2 A and 6??4 A, respectively. The depth sensitivity as well as element specificity of the x-ray resonant Kerr effect offer an elegant way into the investigations of element- and depth-resolved magnetization reversals of ferromagnetic ultrathin regions at buried interfaces in multicomponent multilayer films.open91

Ab initio study of the effect of water adsorption on the carbon nanotube field-effect transistor

We perform density-functional calculations to investigate the effect of adsorbed water molecules on carbon nanotubes (CNTs). Noting that the H2 O molecule has much wider energy gap than the CNT, we find that the charge transfer between them is negligible. We discuss that several recent publications, which claimed a substantial electron transfer from the water molecule to the CNT, have been based on incautious interpretations of the Mulliken population analysis. We suggest that the effect of humidity on nanotube devices may be attributed to various indirect effects enhanced by water vapors, rather than the carrier generations by the physisorbed H2 O molecules.open292

Elevated fasting insulin predicts the future incidence of metabolic syndrome: a 5-year follow-up study

<p>Abstract</p> <p>Background</p> <p>There is controversy about the specific pathophysiology of metabolic syndrome (MS) but several authors have argued that hyperinsulinemia is a key feature of the cluster. We aimed to assess whether the baseline insulin levels could predict the development of MS in a well characterised cohort of otherwise healthy adults who were followed over a five year period.</p> <p>Methods</p> <p>We identified 2, 350 Koreans subjects who did not have MS in 2003 and who were followed up in 2008. The subjects were divided into 4 groups according to the baseline quartiles of fasting insulin, and the predictors of the incidence of MS were analyzed using multivariate regression analysis.</p> <p>Results</p> <p>Over the follow up period, 8.5% of the cohort developed MS. However, 16.4% of the subjects in the highest quartile of the insulin levels developed MS. In a model that included gender, age, the smoking status, the exercise level, alcohol consumption and the systolic blood pressure, the subjects in the highest quartile of the insulin levels had more than a 5 times greater risk of developing MS compared that of the subjects in the lowest quartile. This predictive importance remained significant even after correcting for all the individual features of MS.</p> <p>Conclusions</p> <p>These data suggest that high baseline fasting insulin levels are independent determinants for the future development of MS.</p

Satellite Laser Ranging System at Geochang Sta

Korea Astronomy and Space Science Institute (KASI) has been developing the space optical and laser tracking (SOLT) system for space geodesy, space situational awareness, and Korean space missions. The SOLT system comprises satellite laser ranging (SLR), adaptive optics (AO), and debris laser tracking (DLT) systems, which share numerous subsystems, such as an optical telescope and tracking mount. It is designed to be capable of laser ranging up to geosynchronous Earth orbit satellites with a laser retro-reflector array, space objects imaging brighter than magnitude 10, and laser tracking low Earth orbit space debris of uncooperative targets. For the realization of multiple functions in a novel configuration, the SOLT system employs a switching mirror that is installed inside the telescope pedestal and feeds the beam path to each system. The SLR and AO systems have already been established at the Geochang station, whereas the DLT system is currently under development and the AO system is being prepared for testing. In this study, the design and development of the SOLT system are addressed and the SLR data quality is evaluated compared to the International Laser Ranging Service (ILRS) tracking stations in terms of single-shot ranging precision. The analysis results indicate that the SLR system has a good ranging performance, to a few millimeters precision. Therefore, it is expected that the SLR system will not only play an important role as a member of the ILRS tracking network, but also contribute to future Korean space missions

Hearing Abilities at Ultra-High Frequency in Patients with Tinnitus

ObjectivesTo compare tinnitus patients who have normal hearing between 250 Hz and 8 kHz with normal controls with regard to the ability of each group to hear extended high-frequency pure tone thresholds.MethodsWe enrolled 18 tinnitus patients, each of whom had a threshold of HL <25 dB and threshold differences of <10 dB between ears at frequencies of 250 and 500 Hz and 1, 2, 4, and 8 kHz. We also enrolled age- and gender-matched normal volunteers (10 ears), for each patient. Extended high frequency pure tone audiometry was performed, and the mean hearing thresholds at 10, 12, 14, and 16 kHz of each tinnitus ear were compared with those of the 10 age- and sex-matched normal ears.ResultsOf the 18 patients with tinnitus, 12 had significantly increased hearing thresholds at more than one of the four high frequencies, compared with the normal group. When we assessed results according to frequency, we found that 8 patients had decreased hearing ability at 10 kHz, 10 at 12 kHz, 8 at 14 kHz, and 4 at 16 kHz.ConclusionSome patients with tinnitus who have normal hearing below 8 kHz have decreased hearing ability at extended high-frequencies. Thus, the proportion of patients with tinnitus who have normal hearing over the entire audible range is smaller than in previous reports

Effects of ProstagIand in F2a on the Spontaneous Contractions and Electrical Activities in the Circular Smooth MuscIe of the Guinea-Pig Stomach

Effects of PGF2a and indomethacin on the mechanical and electrical membrane properties of guinea-pig antral smooth muscle were studied using microeletrodes and tension recording technique and whole cell patch clamp technique. In this tissue, indomethacin inhibited the contractility and such an effect was reversed by PGF2a. PGF2a increased spontaneous contractions potently and the frequency and amplitudes of slow waves were also enhanced. PGF2a-induced contractions were not abolished by the pretreatment with nifedipine or by the nominal Ca2+-free condition but were abolished by pretreatment with La3+ or absolute Ca2+-free condition. Ionic currents were also measured by whole cell voltage clamp technique. PGF2a increased the size of voltage operated Ca2+ inward currents, and Ca-dependent K+ outward currents, but had no effect on sustained outward currents. From the above results, it is assumed that PGF2 a acts as an endogenous prostaglandin in the gastric antrum of the guinea-pig. PGF2a has promoting effects on electrical activities and such effects seem to contribute to the increase of contraction, but the greatest part of the increase of contraction is due to receptor-mediated increase of [Ca2+]i. Several possible mechanisms were suggested for the receptor-mediated [Ca2+]i increase

Evaluation of a Laser Altimeter using the Pseudo-Random Noise Modulation Technique for Apophis Mission

Apophis is a near-Earth object with a diameter of approximately 340 m, which will come closer to the Earth than a geostationary orbit in 2029, offering a unique opportunity for characterizing the object during the upcoming encounter. Therefore, Korea Astronomy and Space Science Institute has a plan to propose a space mission to explore the Apophis asteroid using scientific instruments such as a laser altimeter. In this study, we evaluate the performance metrics of a laser altimeter using a pseudorandom noise modulation technique for the Apophis mission, in terms of detection probability and ranging accuracy. The closed-form expression of detection probability is provided using the cross correlation between the received pulse trains and pseudo-random binary sequence. And the new ranging accuracy model using Gaussian error propagation is also derived by considering the sampling rate. The operation range is significantly limited by thermal noise rather than background noise, owing to not only the low power laser but also the avalanche photodiode in the analog mode operation. However, it is demonstrated from the numerical simulation that the laser altimeter can achieve the ranging performance required for a proximity operation mode, which employs commercially available components onboard CubeSat-scale satellites for optical communications