Grain size dependent photoresponsivity in GaAs films formed on glass with Ge seed layers.

The strong correlation between grain size and photoresponsivity in polycrystalline GaAs films on glass was experimentally demonstrated using Ge seed layers with a wide range of grain sizes (1‒330 µm). The crystal evaluations using Raman spectroscopy, scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy revealed that 500-nm-thick GaAs films epitaxially grown from the Ge seed layers at 550 °C inherited the grain boundaries and crystal orientations in Ge. With increasing grain size, the photoresponsivity corresponding to GaAs increased from 0.01 to 3 A W-1 under a bias voltage of 0.3 V. The maximum value approached that of the GaAs film formed simultaneously on a single-crystal Ge wafer, indicating the high potential of the large-grained GaAs film. Knowledge gained from this study will be essential for designing advanced solar cells based on polycrystalline III-V compound semiconductors using inexpensive substrates.

Fabrication of SrGe2 thin films on Ge (100), (110), and (111) substrates.

Semiconductor strontium digermanide (SrGe2) has a large absorption coefficient in the near-infrared light region and is expected to be useful for multijunction solar cells. This study firstly demonstrates the formation of SrGe2 thin films via a reactive deposition epitaxy on Ge substrates. The growth morphology of SrGe2 dramatically changed depending on the growth temperature (300-700 °C) and the crystal orientation of the Ge substrate. We succeeded in obtaining single-oriented SrGe2 using a Ge (110) substrate at 500 °C. Development on Si or glass substrates will lead to the application of SrGe2 to high-efficiency thin-film solar cells.

The application of a vacuum-ultraviolet Fourier transform spectrometer and synchrotron-radiation source to measurements of bands of NO. VII. The final report.

Photoabsorption measurements of NO bands have been made by vacuum-ultraviolet Fourier transform spectrometry with a resolution of 0.12 cm(-1) in the wavelength region of 166.2-196.2 nm. Accurate line positions are obtained for the delta(upsilon,0) bands with upsilon=2, 3, the epsilon(upsilon,0) bands with upsilon=2, 3, and the beta(upsilon,0) bands with upsilon=10,12,14. Absolute term values are found for the corresponding upper levels C(2,3), D(2,3), and B(10,12,14). Accurate rotational line integrated cross sections have also been obtained for the lines in these bands. Integrated cross sections reported in our earlier papers [J. Chem. Phys. 109, 1751 (1998); 112, 2251 (2000); 115, 3719 (2001); 116, 155 (2002); 117, 10621 (2002); 119, 8373 (2003)] have been revised, and the results reported here comprise the delta(upsilon,0) bands with upsilon=0-3, the epsilon(upsilon,0) bands with upsilon=0-3, the beta(upsilon,0) bands with upsilon=6,7,9-12,14, and the gamma(3,0) band. For each band, the band oscillator strength is obtained from the sum of the line strengths of all rotational lines, and these are compared with other published values.

High-Resolution Fourier Transform Emission Spectroscopy of the B(2)Sigma(+) (v = 0)-X(2)Sigma(+) (v = 0) Transition of the PN(+) Ion.

Ultraviolet emission spectrum of the B(2)Sigma(+) (v = 0)-X(2)Sigma(+) (v = 0) transition of the PN(+) ion has been observed at a resolution of 0.05 cm(-1) by a Fourier transform spectrometer. The rotational analysis led to a great improvement of rotational constants in the B(2)Sigma(+) (v = 0) and X(2)Sigma(+) (v = 0) states as well as to the first determination of centrifugal distortion constants for both levels and spin-rotation interaction constant in the X(2)Sigma(+) (v = 0) state. Rotational perturbation in the B(2)Sigma(+) (v = 0) state was observed. Copyright 2000 Academic Press.

High-Resolution Fourier Transform Emission Spectroscopy of the TiCl Radical in the 420-nm Region.

Emission spectra of the TiCl radical in the 420-nm region have been observed at a resolution of 0.04 cm(-1) using a Fourier transform spectrometer. A new electronic assignment of (4)Gamma-X(4)Phi has been proposed. Rotational analysis has been provided for the 0-0 and 1-1 vibrational bands of the (4)Gamma(5/2)-X(4)Phi(3/2) and (4)Gamma(7/2)-X(4)Phi(5/2) spin components and the 0-0 band of (4)Gamma(9/2)-X(4)Phi(7/2). Copyright 2000 Academic Press.

Bioluminescent monitoring of intracellular ATP during fermentation.

The luciferase gene was introduced as a probe into a cell in order to develop a bioluminescent monitoring of intracellular ATP during fermentation. Two plasmids were constructed with two types of promoters. One was pLac-Luc, which had the luciferase gene under the lac promoter to be expressed at a high level. The other was pTet-Luc, which had the luciferase gene under the tetracycline promoter to be stably expressed. A threonine-overproducing strain of Escherichia coli (No. 29-4) was transformed with each plasmid. The recombinant E. coli strains were characterized in their growth, threonine production and luciferase expression. The bioluminescence produced intracellularly from expressed luciferase was detected during fermentation -in a non-destructive manner. The bioluminescent intensity reflected both intracellular ATP and luciferase levels, and the results indicate that stable expression of a luciferase reporter is essential for monitoring intracellular ATP.

Immunochemically distinct NADP-linked isocitrate dehydrogenase isozymes in mitochondria and peroxisomes of Candida tropicalis.

Although peroxisomal localization of NADP-linked isocitrate dehydrogenase (Idp) was first demonstrated in Candida tropicalis, the mitochondrial isozyme has not been found in this yeast. Here we report that the presence of mitochondrial Idp in the yeast was demonstrated by screening for its gene with a DNA probe containing conserved sequences of Idps from various organisms. The nucleotide sequence of the gene (CtIDP1) revealed a 1,290-bp open reading frame corresponding to a 430-amino-acid protein with a high similarity to previously reported Idps. Overexpression of CtIDP1 in Saccharomyces cerevisiae gave a high intracellular Idp activity, and the purified recombinant Idp was shown to be a homodimer with a subunit molecular mass of approximately 44 kDa, different from that of peroxisomal Idp (45 kDa) previously purified from C. tropicalis. Western blot analysis of the subcellular fractions from acetate-grown C. tropicalis with polyclonal antibodies raised against the recombinant CtIdp1 showed that the CtIdp1 in C. tropicalis was localized in mitochondria but not in peroxisomes. Similar levels of CtIDP1 mRNA and its protein product were detected in cells grown on glucose, acetate, and n-alkane, although a slight decrease was observed in n-alkane-grown cells. From these results, CtIdp1 was demonstrated to be mitochondrial Idp. The properties of mitochondrial Idp and peroxisomal Idp isozymes were proven to be similar, but they were immunochemically distinct, suggesting the presence of another gene responsible for peroxisomal Idp in C. tropicalis.

Diffuse axonal injury: its mechanism in an assault case.

Diffuse axonal injury is caused by irreparable shearing of the axons. A case of diffuse axonal injury by a well-witnessed assault is reported. The victim survived for 13 days after the assault. The mode of assault was numerous kicks to the head of the victim lying on the ground. The kicking motion was sideways across the long axis of the body. Thus, on each impact, the victim's head moved with relative freedom or was tossed violently side to side or in a lateral, even angular or rotational, manner. This resulted in a low acceleration/deceleration rate. Grossly, the brain showed no lesions; however, a microscopic lytic lesion was present in the corpus callosum. These injuries were consistent with a grade-2 diffuse axonal injury (Adams classification).

Diffuse axonal injury by simple fall.

Diffuse axonal injury (DAI) is the second most common lethal head trauma after subdural hematoma and probably the most frequent cause of traumatic coma in the absence of an expanding intracranial mass lesion. Though it occurs most often in traffic accidents, it may occasionally result from falls from a height. Previously, it has not been associated with a simple fall or a fall of a distance not more than the victim's own height. We report herein a case of DAI from a simple fall.

Diffuse axonal injury by assault.

A case of diffuse axonal injury (DAI) by assault is reported. The majority of DAI cases documented have been due to traffic accidents and some due to falls from height. DAI is caused by angular or rotational acceleration of the victim's head. The condition is common and is the second most important head injury after subdural hematoma with regard to death. Its clinical picture is characterized by immediate and prolonged coma or demented state. Because of the subtle nature of histological changes in DAI, awareness and intentional search for the lesion is essential. The triad of DAI is as follows: focal lesions (hemorrhages and/or lacerations) in the corpus callosum and brain stem, and microscopic demonstration of axonal damage--retraction balls. The concept of DAI will elucidate and enhance the understanding of many head trauma cases.

Diffuse axonal injury.

Diffuse axonal injury is a distinct form of head injury, induced by direct external forces at the time of the trauma, and not produced by secondary changes due to a primary injury. This type of lesion may be without conspicuous findings on gross brain examination, or may be found with coexisting conventional types of brain injuries. It is characterized by diffuse retraction balls (axonal swellings), hemorrhage or laceration of the corpus callosum, and hemorrhages in the brain stem. It is of utmost importance for forensic pathologists to be aware of this little-recognized entity. Five illustrative cases are presented.

Drug automatism.

The historic development and validity of drug automatism are discussed. Original articles and other publications supporting the concept do not present authenticated cases to validate the concept; therefore, it remains unproved.

Suicide by motor vehicle.

Five suicides by motor vehicle drivers are reported. Possible frequency of such incidents and methods for their investigation, as well as patterns and characteristics of suicidal behavior, are discussed. Published reports of suicide by motor vehicle are scarce. Proven cases should be reported by medical examiners and coroners to help establish the patterns of such deaths.