Spatially resolved inhomogeneous depressions of the excitons Zeeman splitting in an integrated magnetic-multiple quantum wells system

We report on the generation of a nonuniform spatial distribution of the heavy and light-hole excitons in a multiple quantum wells system integrated with a localized inhomogeneous weak magnetic field. An inhomogeneous spatially resolved depression of the Zeeman splittings of the heavy-hole excitons and the light-hole excitons with respect to their translational wave vectors is observed. A localized inverted concentration of the two types of the excitons due to the inhomogeneity of the magnetic field is also measured. A simple method to integrate permanent magnetic materials with the multiple quantum wells system is used to create an accessible degree of control for magnetically manipulating the excitonic distribution

Longitudinal Raman Spectroscopic Observation of Skin Biochemical Changes due to Chemotherapeutic Treatment for Breast Cancer in Small Animal Model

The cancer field effect (CFE) has been highlighted as one of indirect indications for tissue variations that are insensitive to conventional diagnostic techniques. In this research, we had a hypothesis that chemotherapy for breast cancer would affect skin biochemical compositions that would be reflected by Raman spectral changes. We used a fiber-optic probe-based Raman spectroscopy to perform preliminary animal experiments to validate the hypothesis. Firstly, we verified the probing depth of the fiber-optic probe (~800 μm) using a simple intravenous fat emulsion-filled phantom having a silicon wafer at the bottom inside a cuvette. Then, we obtained Raman spectra during breast cancer treatment by chemotherapy from a small animal model in longitudinal manner. Our results showed that the treatment causes variations of biochemical compositions in the skin. For further validation, the Raman spectra will have to be collected from more populations and spectra will need to be compared with immunohistochemistry of the breast tissue

Bile Acid Analysis in Biliary Tract Cancer

The etiology of biliary tract cancer is obscure, but there are evidences that bile acid plays a role in carcinogenesis. To find the association between biliary tract cancer and bile acid, this study compared the bile acid concentration and composition among patients with biliary cancer, biliary tract stones, and no biliary disease. Bile was compared among patients with biliary tract cancer (n = 26), biliary tract stones (n = 29), and disease free controls (n = 9). Samples were obtained by percutaneous transhepatic biliary drainage, endoscopic nasobiliary drainage, or gallbladder puncture, and analyzed for cholic, deoxycholic, chenodeoxycholic, lithocholic, and ursodeoxycholic acid composition. Total bile acid concentration was lower in the cancer group than the biliary stone and control groups; the proportions of deoxycholic (2.2% vs. 10.2% and 23.6%, p < 0.001 and p < 0.001, respectively) and lithocholic acid (0.3% vs. 0.6% and 1.0%, p = 0.065 and p < 0.001, respectively) were also lower. This result was similar when disease site was limited to bile duct or gallbladder. Analysis of cases with bilirubin ≤ 2.0 mg/dL also showed lower total bile acid concentration and deoxycholic acid composition in the cancer group compared to controls (5.7% vs. 23.6%, p = 0.003). Although the presence of bile duct obstruction explains some of the difference in total concentration and composition of bile acid, there are other contributing mechanisms. We suspect the alteration of bile acid transport might decrease bile acid excretion and cause the accumulation of carcinogenic bile acid in bile duct epithelium

The First Very Long Baseline Interferometry Image of 44 GHz Methanol Maser with the KVN and VERA Array (KaVA)

We have carried out the first very long baseline interferometry (VLBI) imaging of 44 GHz class I methanol maser (7_{0}-6_{1}A^{+}) associated with a millimeter core MM2 in a massive star-forming region IRAS 18151-1208 with KaVA (KVN and VERA Array), which is a newly combined array of KVN (Korean VLBI Network) and VERA (VLBI Exploration of Radio Astrometry). We have succeeded in imaging compact maser features with a synthesized beam size of 2.7 milliarcseconds x 1.5 milliarcseconds (mas). These features are detected at a limited number of baselines within the length of shorter than approximately 650 km corresponding to 100 Mlambda in the uv-coverage. The central velocity and the velocity width of the 44 GHz methanol maser are consistent with those of the quiescent gas rather than the outflow traced by the SiO thermal line. The minimum component size among the maser features is ~ 5 mas x 2 mas, which corresponds to the linear size of ~ 15 AU x 6 AU assuming a distance of 3 kpc. The brightness temperatures of these features range from ~ 3.5 x 10^{8} to 1.0 x 10^{10} K, which are higher than estimated lower limit from a previous Very Large Array observation with the highest spatial resolution of ~ 50 mas. The 44 GHz class I methanol maser in IRAS 18151-1208 is found to be associated with the MM2 core, which is thought to be less evolved than another millimeter core MM1 associated with the 6.7 GHz class II methanol maser.Comment: 19 pages, 3 figure

Association of Coffee Consumption with Hearing and Tinnitus Based on a National Population-Based Survey

Coffee is the one of the most common beverages worldwide and has received considerable attention for its beneficial health effects. However, the association of coffee with hearing and tinnitus has not been well studied. The aim of this study was to investigate the association of coffee with hearing and tinnitus based on a national population-based survey. We evaluated hearing and tinnitus data from the 2009&ndash;2012 Korean National Health and Nutrition Examination Survey and their relationship with a coffee consumption survey. All patients underwent a medical interview, physical examination, hearing test, tinnitus questionnaire and nutrition examination. Multivariable logistic regression models were used to examine the associations between coffee and hearing loss or tinnitus. We evaluated 13,448 participants (&ge;19 years) participants. The frequency of coffee consumption had a statistically significant inverse correlation with bilateral hearing loss in the 40&ndash;64 years age group. Daily coffee consumers had 50&ndash;70% less hearing loss than rare coffee consumers, which tended to be a dose-dependent relationship. In addition, the frequency of coffee consumption had an inverse correlation with tinnitus in the 19&ndash;64 years age group but its association was related with hearing. Brewed coffee had more of an association than instant or canned coffee in the 40&ndash;64 years age group. These results suggest a protective effect of coffee on hearing loss and tinnitus

Entrance length, turbulence intensity, and local pressure measurement in microchannel flows

Fundamental aspects of the channel flows were experimentally investigated in a microchannel with the planar upstream geometry, i. e. the entrance length and the critical Reynolds number. The effects of the upstream reservoir geometry resulting from typical microfabrication processes on the entrance length of a rectangular microchannel has been studied for a large range of Reynolds numbers (i.e. 1, 10, 20, 30, 50, 70, 100, 210, 1030, 1810, and 2100). The microchannel dimension was 252.29 μm × 694.15 μm × 120 mm. Micro particle image velocimetry was used to measure the velocity profiles in the microchannel. An almost constant entrance length is found for low Reynolds number flows. The entrance lengths for ReD = 210 and 1030 show ∼50% reduction while the entrance lengths are increased for Re = 1810 and 2100 by ∼80%. There exists a nonlinear relation between the entrance length and Reynolds number in the range of 1030 ≤ ReD ≤ 1810. Since the channel has far larger scale compared to where the continuum theory breaks down, the effect is solely from the entrance geometry change. Critical Reynolds number in a rectangular microchannel has been investigated. Laminar flow behavior is observed up to ReD = 2100 while transitional flow is generated at ReD = 2940 in agreement with well established macroscopic observations. Turbulence intensity is calculated and confirms that transition occurs between Reynolds numbers 2100 and 2940. In addition, a new correlation analysis for turbulence intensity measurement has been developed. The results are compared with the turbulence intensity calculated from the velocity field. The turbulence intensity derived from the correlation analysis showed the very close trend compared to the turbulence intensity measured from the velocity field. An inexpensive and simple pressure measurement technique which could be used in a microchannel using air compression is demonstrated. The ideal gas law and surface tension are used to measure the local static pressure in the microchannel. The prototype device was built with SU-8. For the interfacial pressure jump calculation, the contact angle of a water drop on an SU-8 surface was measured and the contact angle was found as 76.0° ± 6°. Because of the complicated boundary condition of the pressure tap, an accurate interfacial pressure jump was not acquired. Long pressure taps showed better sensitivity. The measured pressure shows lower values than the theoretically calculated values. However, the sensor can still be calibrated and used for pressure measurement

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Most heat flux sensors have a large thickness of thermal resistance materials, and hence the sufficient temperature gradients along the thicknesses. They also require heat sinks and cooling methods to maintain the temperature gradients. In this work, we presents a small chip sized radiation heat flux sensor which is composed of two Pt-RTDs where one is gold-coated and the other is not. The gold film reflects radiation heat flux, so that the steady state temperature of the temperature sensor is different from that of the sensor without the gold film. This temperature difference can be correlated with radiation heat flux. Micro-fabricated Pt-RTDs showed an approximate TCR (Temperature Coefficient of Resistance; between 100 oC and 300 oC) of 2830 (??/??/oC). The sensors can be used up to 350 oC, and the heat flux of 3.5 kW/m2 with a convection heat transfer coefficient of 10 W/m2K at 50 oC. This heat flux sensor can be attached to smart clothes for firefighters and measure temperature as well as the radiation heat flux with a fast response time in a harsh environment