Photoconductive terahertz transceiver

A photoconductive dipole antenna can be used as a transceiver, which alternately transmits pulsed electromagnetic radiation and receives the return signal. Preliminary results of using a photoconductive terahertz transceiver with femtosecond optics are reported     

Finite Larmor radius effects on ripple diffusion in tokamaks

The confinement of alpha particle is important in tokamaks. The trajectory or confinement of alpha particles is often calculated with guiding center approximation. The features of spherical tokamak can break the approximation. We investigate finite Larmor radius effect. The orbit calculated by equation of motion is different, especially in toroidal direction, from that by guiding center equations. This difference causes difference of ripple resonance energy and the difference of the peaks of the diffusion coefficients. Furthermore, because of the additional free parameter, Larmor phase, the peaks of diffusion coefficient calculated by equation of motion are broader than those by guiding center equations.     

The structures and functions of ice crystal-controlling proteins from bacteria

Many organisms have evolved into unique mechanisms which minimize freezing injury due to extracellular ice formation. Specifically, certain bacteria have produced a few proteins each with different functions. For example, the ice nucleation protein acts as a template for ice formation, which is responsible for imparting ice nucleating activity. The anti-nucleating protein inhibits the fluctuation of ice nucleus formation by a foreign particle in the water drop. Also, the antifreeze proteins depress the freezing temperature, modify or suppress ice crystal growth, inhibit ice recrystallization, and protect the cell membrane from cold-induced damage. In this article, a review on the current knowledge of the structure and the function of these three types of proteins, which are capable of interacting with ice itself or its nuclei from bacteria.     

Functional analysis of genes encoding putative oxidoreductases in Aspergillus oryzae, which are similar to fungal fructosyl-amino acid oxidase

We found 11 genes (FAO1-11) encoding putative oxidoreductases in the Aspergillus oryzae genome, which are similar to fungal fructosyl-amino acid oxidases. The cDNAs corresponding to the genes were cloned and expressed in Escherichia coli. rFao2 had fructosyl-amino acid oxidase activity, whereas rFao1 did not show any enzyme activity, even though the deduced amino acid sequence of Fao1 is identical to that of one of the fructosyl-amino acid oxidase isozymes from Aspergillus oryzae. rFao7 and rFao8 showed oxidase activity toward sarcosine, L-pipecolate, and L-proline. rFao10 was active toward only sarcosine, of the substrates tested. The functions of the other proteins were also predicted from a phylogenetic analysis.     

Two acyl-CoA dehydrogenases of Acinetobacter sp. strain M-1 that uses very long-chain n-alkanes

Two genes encoding acyl-CoA dehydrogenases, acdA and acdB, arranged in tandem, were found in the chromosomal DNA of Acinetobacter sp. strain M-1. AcdA was purified from the parental strain and AcdB was purified from an Escherichia coli strain expressing the cloned gene. The substrate specificities of the two enzymes suggest that AcdA is a medium-chain acyl-CoA dehydrogenase and that AcdB is a long-chain acyl-CoA dehydrogenase. Characterization of n-alkane metabolism in Acinetobacter sp. strain M-1 has revealed parallel pathways as well as enzymes with overlapping specificities in a single pathway. The two acyl-CoA dehydrogenases described here provide another example of the physiological complexity underlying n-alkane utilization.     

Involvement of the skull base and vault in chronic idiopathic hyperphosphatasia

OBJECTIVE: To evaluate whether mutation in the exon 10 of the fibroblast growth factor receptor 3(FGFR3) gene in common in Chinese patients with achondroplasia. METHODS: Genomic DNA from seven sporadic cases of achondroplasia was studied by using PCR-SSCP and restriction enzymes. RESULTS: All patients carried the same glycine-to-arginine mutation at codon 380(G380R) of the transmembrane domain of FGFR3. CONCLUSION: The results suggest that the G380R mutation of FGFR3 is also a frequent mutation causing achondroplasia in Chinese. Detecting FGFR 3 gene mutation with PCR-SSCP and restriction enzymes analysis is a convenient, rapid and reliable molecular diagnostic assay for prenatal and early diagnosis of achondroplasia.     

An autopsy case of cytokeratin 7-positive minute adenocarcinoma of the lung with systemic metastases

We describe a 60-year-old woman with leg pain. Although metastatic bone tumor and atypical cells mimicking signet-ring cells in the bone marrow picture were observed, systemic survey revealed no primary lesion. The patient died two months after admission from systemic progress of the disease. Autopsy revealed a small focus of adenocarcinoma within the right upper lobe of the lung and systemic metastases without any particular changes in the gastrointestinal tract. The tumor cells of the lung were diffusely positive for cytokeratin 7, whereas cytokeratin 20 immunoreactivity was weak and focal, and that supported the lung origin of the present tumor. Moreover, the tumor cells in the bone marrow showed a similar pattern in immunoreactivity. These findings suggest that cytokeratin 7 and cytokeratin 20 immunoreactivity is helpful for the premortem diagnosis of the metastatic tumor of unknown origin.     

Polymorphism in the promoter region of the alpha 2A adrenergic receptor gene and mood disorders

Alpha 2 adrenergic receptors are thought to play a crucial role in the etiology or treatment of mood disorders. Polymorphism(s) in the promoter region of the alpha 2 receptor may affect the gene expression and be associated with mood disorders. We studied the previously reported polymorphisms of the alpha 2A receptor gene at position-1291 in 114 healthy controls and 103 mood disorder patients. There was statistically no difference between controls and patients in either the genotype or the allele frequency. There was statistically no difference between the genotype and the clinical characteristics. Our results suggest there is no association between this polymorphism in the promoter region of the alpha 2A receptor gene and mood disorders.     

Postbuckling behaviour of stainless steel (SUS304) columns under loading-unloading cycles

Based on the equilibrium configuration paths, this study investigates the postbuckling behaviour, including the shape recovery capability, of stainless steel (SUS304) columns after a complete loading-unloading cycle. Experiments were conducted and later numerical simulation was carried out in order to analyze the observed buckling and postbuckling behaviour. Large deflection analysis is necessary for slender columns. Moreover, comparison of the experimental critical load with analytical predictions verifies the fact that physical nonlinearity should be taken into account to analyze the column’s buckling behaviour comprehensively. Thus, based on large deflection theory as well as the nonlinear stress-strain relations, the load-deformation curves of the columns during a complete loading-unloading cycle have been predicted by using the finite element modelling (FEM) code ANSYS.Precise and quantitative analyses of the results verify the fact that the material’s stress-strain properties, both in tension and compression, attribute to the column’s buckling behaviour.