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101.
102.
The microstructures and mechanical properties of amorphous/nanocrystalline hybrid TiNi wires produced by severe cold drawing were investigated. Annealed wires of Ti-50.9?mol%Ni and Ti-41?mol%Ni-8.5?mol%Cu were subjected to severe cold drawing of 50-70% reduction. The as-drawn TiNi wires were composed of the mixture of amorphous phase and predominantly B2 nanocrystalline phase. Young??s modulus increased with the drawing reduction which can be attributed to the increase in the amount of amorphous phase. For the binary TiNi wires, the volume fraction of amorphous phase was estimated to be about 60% from Young??s modulus and electrical resistivity. The wires drawn over 60% exhibited peculiar large linear elastic strain which is quite different from superelasticity. Aging at 573?K led to an increase in tensile elongation as well as in the recoverable strain. The amorphization by cold drawing was also confirmed for Ti-41?mol%Ni-8.5?mol%Cu in 62% drawn wires.  相似文献   
103.
The electricity for the electrolyzer is supplied by a variable electricity supply unit that simulates actual outputs of both series and parallel combinations of solar cells exposed to various solar intensities. An amorphous-silicon solar cell is used as a sensor for the unit The operation was continued for more than 600 days without trouble. The case of direct connection of the solar cell and polymer electrolyte (PE) water electrolyzer is simulated: the test results show that more than 95% of the peak electricity power of the solar battery can be utilized for the electrolyzer over various solar radiation conditions.  相似文献   
104.
Reconstitution of tissue architecture in vitro is important because it enables researchers to investigate the interactions and mutual relationships between cells and cellular signals involved in the three-dimensional (3D) construction of tissues. To date, in vitro methods for producing tissues with highly ordered structure and high levels of function have met with limited success although a variety of 3D culture systems have been investigated. In this study, we reconstituted functional hepatic tissue including mature hepatocyte and blood vessel-like structures accompanied with bile duct-like structures from E15.5 fetal liver cells, which contained more hepatic stem/progenitor cells comparing with neonatal liver cells. The culture was performed in a simulated microgravity environment produced by a rotating wall vessel (RWV) bioreactor. The hepatocytes in the reconstituted 3D tissue were found to be capable of producing albumin and storing glycogen. Additionally, bile canaliculi between hepatocytes, characteristics of adult hepatocyte in vivo were also formed. Apart from this, bile duct structure secreting mucin was shown to form complicated tubular branches. Furthermore, gene expression analysis by semi-quantitative RT-PCR revealed the elevated levels of mature hepatocyte markers as well as genes with the hepatic function. With RWV culture system, we could produce functionally reconstituted liver tissue and this might be useful in pharmaceutical industry including drug screening and testing and other applications such as an alternative approach to experimental animals.  相似文献   
105.
Batch-autoclave experiments have been conducted to evaluate the potential use of synthetic fluid inclusions as a simultaneous temperature–pressure (and fluid sampling) logging tool in deep-seated, high-temperature (>350 °C) geothermal systems. The application of synthetic fluid inclusions allows us to obtain information about thermal-pressure conditions in deep-seated geothermal systems, where conventional tools cannot be used because of the extreme temperature conditions. Fluid inclusions, up to 50 μm long, have been readily synthesized during 5-day autoclave experiments (conducted at 375–475 °C and 39–62 MPa) in pre-fractured, inclusion- and impurity-free artificial quartz. Inferred fluid inclusion (temperature–pressure) trapping conditions are calculated by deducing the intersection of isochores derived from microthermometric data for three sets of simultaneously trapped synthetic fluid inclusions in healed microfractures. Synthetic fluid inclusion logging offers a precise borehole temperature measurement technique without need of any pressure correction. Pressure estimates are less precise, although the method may be improved by using a combination of H2O–NaCl and H2O–KCl solutions/salinities, and fluid/quartz/amorphous silica systems that facilitate crack healing but trap fluids that do not homogenize at near-critical conditions.  相似文献   
106.
We describe the electrochemical detection of DNA methylation through the direct oxidation of both 5-methylcytosine (mC) and cytosine (C) in 5'-CG-3' sequence (CpG) oligonucleotides using a sputtered nanocarbon film electrode after digesting a longer CpG oligonucleotide with endonuclease P1. Direct electrochemistry of the longer CpG oligonucleotides was insufficient for obtaining the oxidation currents of these bases because the CG rich sequence inhibited the direct oxidation of each base in the longer CpG oligonucleotides, owing to the conformational structure and its very low diffusion coefficient. To detect C methylation with better quantitativity and sensitivity in the relatively long CpG oligonucleotides, we successfully used an endonuclease P1 to digest the target CpG oligonucleotide and yield an identical mononucleotide 2'-deoxyribonucleoside 5'-monophosphate (5'-dNMP). Compared with results obtained without P1 treatment, we achieved 4.4 times higher sensitivity and a wider concentration range for mC detection with a resolution capable of detecting a subtle methylated cytosine difference in the CpG oligonucleotides (60mer).  相似文献   
107.
The current understanding of the resonant tunneling process of electrons in double-barrier (DB) diodes and in coupled quantum well structures is described. The authors examine the validity of the simple Fabry-Perot model in describing the electron transport in actual DB diodes. They then describe a picosecond laser study to clarify the dynamics of resonant tunneling, including the intrinsic time delay associated with the multiple reflection of electron waves. Lastly, they discuss both the current state and prospects of device applications for high-speed electronics and optoelectronics  相似文献   
108.
This study was undertaken to determine whether melatonin (N-acetyl-5 methoxytryptamine) is effective in helping emergency medical services (EMS) personnel who work rotating night shifts reset their biological clocks and minimize circadian rhythm disruption. A double-blinded, randomized, crossover study was performed using 22 volunteers. Participants were working a span of consecutive night (2300 to 0700 hours) shifts and received either a melatonin capsule (6 mg) or placebo to be taken before each of the consecutive day sleeps. Each participant completed a total of 4 spans of consecutive night shifts (2 melatonin, 2 placebo). Collected data included daily sleep diaries, quantification of alcohol/caffeine consumed, and drug side effects. Assessment of sleep quality, posttreatment mood, and workload ratings were measured daily by 10-cm visual analog scale (VAS). Analysis of sleep diaries found no significant difference (P > .05) between the two treatments with respect to mean sleep latency, duration, and efficiency, and subjectively rated sleep quality. Similarly, no significant benefits were noted between the median VAS scores for daily posttreatment mood or workload ratings. Adverse effects were rare; one patient taking melatonin reported a prolonged sedative effect. Despite recent interest in melatonin for treatment of circadian-based sleep disorders, no clinical benefits were noted in EMS personnel working rotating night shifts.  相似文献   
109.
Social competence in subjects at risk for schizophrenia and affective disorder and in normal-comparison subjects was examined in childhood and adolescence. Based on interviews with the parents of the subjects and with the children and adolescents themselves, subjects at risk for schizophrenia had poorer overall social competence than subjects at risk for affective disorder and comparison subjects in early adolescence and adolescence but not in childhood. In analyses of specific aspects of social competence, the adolescents at risk for schizophrenia had significantly poorer peer relationships and decreased hobbies/interests than the adolescents at risk for affective disorder and the normal-comparison adolescents. With respect to school adjustment, however, the two groups of adolescent offspring of parents with psychiatric disorders had significantly poorer adjustment than the comparison adolescents but did not differ from each other on this measure. These results suggest that various aspects of poor social competence may precede the onset of schizophrenia and play an important role in its development.  相似文献   
110.
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