Turbulence enhancement by ultrasonically induced gaseous cavitation in the CO2 saturated water

Recent primary concern for the design of high performance heat exchanger and highly integrated electronic equipments is to develop an active and creative technologies which enhance the heat transfer without obstructing the coolant flows. In this study, we found through the LDV measurement that the gaseous cavitation induced by ultrasonic vibration applied to the CO₂ saturated water in the square cross-sectioned straight duct flow enhances the turbulence much more than the case of non-ultrasonic or normal ultrasonic conditions without gaseous cavitation does. We also found that gaseous cavitation can enhance effectively the turbulent heat transfer between the heating surfaces and coolants by destructing the viscous sublayer.     

Simultaneous measurement of dissolved oxygen concentration and velocity field in microfluidics using oxygen-sensitive particles

This paper reports a technique for measuring the velocity and dissolved oxygen concentration (DOC) fields simultaneously in a micro-scale water flow using oxygen-sensitive particles (OSP) and a conventional microparticle image velocimetry method. The OSP were fabricated using a dispersion polymerization method by synthesizing platinum (II) octaethyporphyrin (PtOEP) with polystyrene, and used as tracer particles and oxygen sensors. An ultraviolet light-emitting diode with a wavelength of 385 nm was used as the excitation light source, and phosphorescence images of OSP were captured on a CMOS high-speed camera. The interrogation window concept was used to measure the DOC in water from the dispersed phosphorescence intensity distribution of OSP. The Stern–Volmer equations in the interrogation windows were obtained from in situ calibration. Water containing OSP with DOC values of 0 and 100 % were injected into a Y-shaped microchannel using a double loading syringe pump. The velocity and DOC field over the entire channel area were quantified.     

Effects of Annealing Temperature on Microstructure and Tensile Properties in Ferritic Lightweight Steels

An investigation was conducted into the effects of annealing temperature on microstructure and tensile properties of ferritic lightweight steels. Two steels were fabricated by varying the C content, and were annealed at 573 K to 1173 K (300 °C to 900 °C) for 1 hour. According to the microstructural analysis results, κ-carbides were formed at about 973 K (700 °C), which was confirmed by equilibrium phase diagrams calculated from a THERMO-CALC program. In the steel containing low carbon content, needle-shaped κ-carbides were homogeneously dispersed in the ferrite matrix, whereas bulky band-shaped martensites were distributed in the steel containing high carbon content. In the 973 K (700 °C)-annealed specimen of the steel containing high carbon content, deformation bands were formed throughout the specimen, while fine carbides were sufficiently deformed inside the deformation bands, thereby resulting in the greatest level of strength and ductility. These results indicated that the appropriate annealing treatment of steel containing high carbon content was useful for the improvement of both strength and ductility over steel containing low carbon content.     

Modeling for multilevel switching in oxide-based bipolar resistive memory

We report a physical model for multilevel switching in oxide-based bipolar resistive memory (ReRAM). To confirm the validity of the model, we conduct experiments with tantalum-oxide-based ReRAM of which multi-resistance levels are obtained by reset voltage modifications. It is also noticeable that, in addition to multilevel switching capability, the ReRAM exhibits extremely different switching timescales, i.e. of the order of 10(-7)?s to 10(0)?s, with regard to reset voltages of only a few volts difference which can be well explained by our model. It is demonstrated that with this simple model, multilevel switching behavior in oxide bipolar ReRAM can be described not only qualitatively but also quantitatively.     

Sunitinib release from biodegradable films of poly(l-lactide-co-caprolactone)

The aim of this study was to prepare sunitinib-loaded biodegradable films using poly(l-lactide-co-?-caprolactone) (PLCL) for anti-tumor drug delivery. Sunitinib-loaded PLCL film has a rough surface, while empty film has a smooth surface. PLCL film loaded with 5% (w/w) sunitinib showed an absence of a crystalline peak of sunitinib, while sharp peaks were observed at 10% (w/w) loading, indicating that sunitinib was molecularly distributed in the polymer matrix at 5% (w/w). A drug release study revealed an initial burst during the first 2 h, followed by continuous release until 24 h. Since weight loss of film was <10% for 1 week, drug release mechanism was dominantly dependent on the diffusion-mediated release of drugs to the medium. Sunitinib has a dose-dependent anti-proliferation effect against HuCC-T1 human cholangiocarcinoma cells in vitro. These results indicate that sunitinib-loaded PLCL film is a appropriate candidate as a vehicle for anti-tumor drug delivery.     

Prognosis of breast cancer is associated with one-carbon metabolism related nutrients among Korean women

ABSTRACT: BACKGROUND: The 5-year survival rate for breast cancer among Korean women has increased steadily; however, breast cancer remains the leading cause of cancer mortality among women. One-carbon metabolism, which requires an adequate supply of methyl group donors and B vitamins, may affect the prognosis of breast cancer. This aim of this study was to investigate the associations of dietary intake of vitamin B2, vitamin B6 and folate before diagnosis on the prognosis of breast cancer. METHODS: We assessed the dietary intake using a food frequency questionnaire with 980 women who were newly diagnosed and histopathologically confirmed to have primary breast cancer from hospitals in Korea, and 141 disease progression events occurred. Cox's proportional hazard regression models were used to estimate the hazard ratio (HR) and 95% confidence interval (95% CI) adjusting for age, education, recruitment sites, TNM stage, hormone status, nuclear grade and total calorie. RESULTS: There was no significant association between any one-carbon metabolism related nutrients (vitamin B2, B6 and folate) and the progression of breast cancer overall. However, one-carbon metabolism related nutrients were associated with disease progression in breast cancer patients stratified by subtypes. In ER + and/or PR + breast cancers, no association was observed; however, in ER--/PR-- breast cancers, a high intake of vitamin B2 and folate statistically elevated the HR of breast cancer progression (HR = 2.28; 95% CI, 1.20-4.35, HR = 1.84; 95% CI, 1.02-3.32, respectively) compared to a low intake. This positive association between the ER/PR status and progression of the disease was profound when the nutrient intakes were categorized in a combined score (Pinteraction = 0.018). In ER--/PR-- breast cancers, high combined scores were associated with a significantly poor DFS compared to those belonging to the low score group (HR = 3.84; 95% CI, 1.70-8.71). CONCLUSIONS: In conclusion, our results suggest that one-carbon related nutrients have a role in the prognosis of breast cancer depending on the ER/PR status.     

Improvement of the performance of a tetrahedral element with rotational DOFs using strain smoothing techniques

In this paper, the performance of a 4-node tetrahedral element with rotational DOFs is improved using strain smoothing techniques. A partition-of-unity based approximation is used to construct the tetrahedral element with rotational DOFs. To overcome the stiff behavior of the tetrahedral element with rotational DOFs, a face-based strain smoothing technique is used. The stiffness matrix is expressed explicitly and the element performance is evaluated through numerical examples, which demonstrate that the proposed strain smoothed tetrahedral elements with rotational DOFs satisfy the patch test and have a better performance than other tetrahedral elements with rotational DOFs.     

Experimental realization of ‘universal homodyne tomography’ with a single local oscillator

We report preliminary experimental measurement of the twin-beam quantum state via optical homodyne tomography using a single local oscillator. The experiment is a realization of the recently reported ‘universal homodyne tomography’ technique. The results agree well with theoretical predictions and reveal the non-classical photon-number correlation between the signal and idler photons of the twin-beam state.     

Layered Nanoprobe for Long‐Lasting Fluorescent Cell Label

A long‐lasting particle‐based fluorescent label is designed for extended cell imaging studies. This onion‐like nanoprobe is constructed through layer‐by‐layer fabrication technology. The nanoprobes are assembled with multiple layers of optically quenched polyelectrolytes, the fluorescence signal of which can be released later by intracellular proteolysis. Upon incubation with cells, the assembled nanoprobes are taken up efficiently. The tight packing and layered assembly of the quenched polyelectrolytes slow subsequent intracellular degradation, and then result in a prolonged intracellular fluorescence signal for up to 3 weeks with no noticeable toxicity.