Texture development of Ca3Co4O9 thermoelectric oxide by high temperature plastic deformation and its contribution to the improvement in electric conductivity

High temperature uniaxial compression is conducted on Ca₃Co₄O₉ layered cobaltite, in order to achieve a thermoelectric oxide with low resistivity by the development of (0 0 1) texture. It is found that flow stress varies depending on deformation temperature and strain rate. Development of a sharp texture having the maximum (0 0 1) pole density of about 33 times as high as the random level is achieved. It is found that the high temperature compression process is quite effective for the simultaneous achievement of densification and (0 0 1) texture development. It is experimentally confirmed that resistivity decreases drastically by the construction of a sharp (0 0 1) texture.     

Systematic Magnetization Measurements on Single Crystalline Bi2Sr2CaCu2O8+δ with Columnar Defects

We have performed systematic magnetization measurements on single crystalline Bi ₂ Sr ₂ CaCu ₂ O ₈₊ with columnar defects of B = 0.005 to 1 T by using a SQUID magnetometer. Magnetization hysteresis curves of the pristine sample show a weak irreversible behavior in the vortex liquid state, suggesting the existence of the new vortex state in the vortex liquid state. This weak irreversible region persists systematically in the samples with columnar defects even up to B = 1 T. It is shown that the weak hysteresis of magnetization is sensitive to the disorder level of the sample and shifts systematically to higher temperature and field region with increasing the number of columnar defects. This behavior clearly indicates that effective pinning mechanism exists even in the vortex liquid state and generates a finite critical current.     

Wortmannin inhibits repair of DNA double-strand breaks in irradiated normal human cells

Recently the concept of dissociative identity disorder (formerly known as multiple personality disorder) has attracted increasing public and scientific interest. However, it is rarely diagnosed in the clinical setting. the reported case of a 47-year-old woman with a history of child abuse demonstrates the problems of differential diagnosis. A number of psychopathologic symptoms pointed to a multiple personality disorder, but in the follow-up psychotic symptoms such as delusions, possible hallucinations and bizarre behavior clearly emerged. The differential diagnosis of dissociative identity disorder includes paranoid schizophrenia, as in the case described, borderline personality disorder, hysteria, simulation and the false memory syndrome. Finally, social and cultural factors have to be considered.     

Low-threshold CW operation of square-shaped semiconductor ring lasers (orbiter lasers)

The CW operation of square-shaped semiconductor ring lasers is demonstrated with a threshold current as low as 6 mA. The ring resonator consists of straight waveguides and four total reflection mirrors. The lasers are fabricated using Br/sub 2/ dry etching on an InGaAs/GaAs strained single-quantum-well graded-index separate-confinement heterostructure wafer. The low-threshold CW operation is due to the high differential gain of the wafer and the low-loss total reflection mirror.<>     

Control of unidirectional oscillation in semiconductor orbiterlasers

Unidirectional oscillation in a ring-resonator-type semiconductor laser was demonstrated in a square-shaped orbiter laser using an optical feedback mechanism. The bistable switching phenomenon between the unidirectional and bidirectional oscillation was observed synchronized with the switching of the longitudinal lasing mode. A longitudinal-mode bistability results from the compound cavity system formed by the orbiter laser and output waveguide. The feedback light from the output waveguide end interferes with the orbiter lasing light. Switching between the unidirectional and bidirectional oscillation was controlled by injecting a current into the output waveguide, which varies the phase condition of the feedback light     

Induction of DNA double-strand breaks by restriction enzymes in X-ray-sensitive mutant Chinese hamster ovary cells measured by pulsed-field gel electrophoresis

This investigation was designed to determine whether the cytotoxic effects of different restriction endonucleases are related to the number and type of DNA double-strand breaks (DSBs) they produce. Chinese hamster ovary (CHO) K1 and xrs-5 cells, a radiosensitive mutant of CHO K1, were exposed to restriction endonucleases HaeIII, HinfI, PvuII and BamHI by electroporation. These enzymes represent both blunt and sticky end cutters with differing recognition sequence lengths. The number of DSBs was measured by pulsed-field gel electrophoresis (PFGE). Two forms of PFGE were employed: asymmetric field-inversion gel electrophoresis (AFIGE) for measuring the kinetics of DNA breaks by enzyme digestion and clamped homogeneous gel electrophoresis (CHEF) for examining the size distributions of damaged DNA. The amount of DNA damage induced by exposure to all four restriction enzymes was significantly greater in xrs-5 compared to CHO K1 cells, consistent with the reported DSB repair deficiency in these cells. Since restriction endonucleases produce DSBs alone as opposed to the various types of DNA damage induced by X rays, these results confirm that the repair defect in this mutant involves the rejoining of DSBs. Although the cutting frequency was directly related to the length of the recognition sequence for four restriction enzymes, there was no simple correlation between the cytotoxic effect and the amount of DNA damage produced by each enzyme in either cell line. This finding suggests that the type or nature of the cutting sequence itself may play a role in restriction enzyme-induced cell killing.     

Newly developed walking apparatus for identification of obstructions by visually impaired people

In this work, two visual systems to help visually impaired people walk were developed: the first is a white cane with a non-contact detection system, and the second is a three-dimensional (3D) visual system. In place of the sense of sight, the sense of touch, either via vibration or of pins, can relay information on objects and obstacles around people. In a white cane non-contact detection system, two sets of ultrasonic sensors and vibrators, respectively, are employed to indicate the positions of both low- and high-level obstructions in front of the visually impaired person. When objects are detected by the sensor, the vibrator is strongly activated. In this system, the range of obstruction detection can be adjusted between 0.5 m and 5.5 m. By comparison, the 3D visual system uses two different components, an infrared camera sensor to detect obstructions and a tooling apparatus, incorporating a number of 1 mm diameter pins, by which their 3D shapes are derived. The pins are arranged in a 10×10 matrix and move longitudinally between the retracted and extended positions based on the depth data between the infrared sensor and the obstruction. Pins are elongated individually, so that each pin tip represents a specific area of the outer surface of the object. This tactile 3D image can provide effective object information.     

Detection of K-ras point mutations in the supernatants of peritoneal and pleural effusions for diagnosis complementary to cytologic examination

OBJECTIVE: The present study aimed to examine the discriminatory ability of alcohol expectancies and drinking refusal self-efficacy and to identify the differential role of these constructs in social and problem drinkers. METHOD: Drinkers (N = 276) were self-selected from general (n = 185) and clinical (n = 91) populations to complete a 40-minute questionnaire that asked about alcohol expectancies, drinking refusal self-efficacy, consumption, degree of dependence and demographics. RESULTS: The results showed that in social drinkers both the expectancy and self-efficacy constructs were reliably able to discriminate between types of drinker. Expectancy was related to consumption in social drinkers, but did not appear to account for a significant proportion of the variance in problem drinkers. CONCLUSIONS: The findings are discussed in terms of a two-process model of drinking behavior that suggests that expectancies operate differently in social and problem drinkers.     

Spin glass behavior of Mn2+ ions in zeolite-Y at very low temperature

Magnetic properties of manganese ion spin systems in zeolite-Y have been measured. These ions act as almost free ions in the zeolite. Low frequency ac-susceptibility can be described with the Curie-Weiss law down to 50 mK. The susceptibility has a maximum around 30 mK showing a magnetic anomaly. Characteristic relaxation times deduced from frequency dependence of the maxima are studied. They diverge towardsT _c = 0 K according to the following formula, = ₀exp{(b/T)⁺¹} where ₀ = 3 x 10_–10 sec, b = 0.28K, and = 0.4, respectively. It is expected from ESR measurements that the dominant interaction between the manganese ions is dipole-dipole like. This divergence is interpreted as that of a dipolar spin glass.