Structures of altiloxins a and b,phytotoxins from phomaasparagi sacc

By spectroscopic data, the structures of two new phytotoxins, altiloxins a and b from Phoma asparagi sacc., the incitant of stem blight disease on asparagus are elucidated.     

Synthetic studies on β-lactam antibiotics. 13. Transformation of 6-epipenicillins to 2R-{(1S, 5R)-2-oxa-6-oxo-4,7- diazabicyclo[3.2.0]hept-3-en-7-yl}-3-methylbut-3-enoates

Reaction of 2β-unsubstituted or functionalized-methyl 6-epipenicillin sulfoxides $\text{2}$ with tervalent phosphorus compounds gave azetidinone-epi-oxazolines $\text{3}$, important intermediates in synthesis of 7α-methoxy-1-oxacephems. Preparation of the 2β-functionalized-methyl substrates is described also.     

General synthesis of exomethylene-α-lactones via the retro-diels-alder reaction

New synthetic methods of tulipalin A were deviced via the retro-Diels-Alder reaction and the generality was demonstrated by the synthesis of several α-methylene-α-alkyl-α-butyrolactones.     

Comparison of the shape parameters of DNA-cationic lipid complexes and model polyelectrolyte-lipid complexes

In this study, we used a rheological method to study the shape of DNA-cationic lipid complexes and model polyelectrolyte-lipid complexes. We introduced two kinds of anionic polyelectrolytes, sodium polygalacturonate (PGU) and sodium dextran sulfate (DSS), of varying size, as models for DNA. The prepared complexes were incubated under laminar flow conditions. The results show the same quantitative relation between the shape parameter of lipoplexes and the length of anionic polyelectrolytes, including DNA. The rheological behavior of PGU and DSS were similar to that of DNA.     

Near Infrared Imager with a Flexible Source-Detector Arrangement and a New Detection Gain Control

This paper describes a new near infrared (NIR) spectroscopic imager that has an expanded detection dynamic range intended for measurements with various transmitter-receiver (T-R) distances. Simultaneous multi-distance measurements for 48 points of the human forehead were performed to record brain activation by a mental test called digit span. Similarity Index (SI) analysis of 48 time-course curves was introduced for the evaluation of the result. A new mapping method toward depth direction is also shown for total hemoglobin and SI values. Simultaneous multi-distance measurements are useful for the brain functional analysis to distinguish depth variation.     

Usefulness of MR-seminography using Gd-DTPA in intermediate magnetic field MRI equipment

T(2)-weighted fast advanced spin-echo imaging with gadolinium (hereinafter referred to as "MR-seminography") of the genital tract was evaluated for its usefulness in non-invasive investigation into the morphology of these organs. Twenty healthy male volunteers who are confirmed as free of genital tract obstruction were entered into the study. The genital tract was imaged using the 0.5 T MRI system by fast advanced spin echo (FASE) method. Based on quantitative evaluation, visibility evaluation, and the visualization of the genital tract in each subject, the contrast-enhanced images were assessed in comparison with those at pre-injection of the contrast agent by four specialists. Also examined were the morphology of the seminal vesicle according to age group using "Ishigami-Mori's classification," and the age angle of the main ducts. MR-seminography produced high contrast images and revealed a significantly decreased signal in the pelvic organs under investigation. In the analysis of individual subjects, the area from the proximal portion of the vas deferens to the ampulla and the seminal vesicles was on the whole well visualized except for the distal portion of the vas deferens and the ejaculatory duct. With regard to seminal vesicle morphology, type II was predominant. The age angle showed a trend toward widening with age. MR-seminography is non-invasive, useful, and therefore a highly recommended procedure for observation of the morphology in the area from the proximal portion of the vas deferens to the seminal vesicle.     

Depth control of a silicon structure fabricated by 100q keV Ar ion beam lithography

Ion beam lithography of a silicon surface using an Ar ion beam with an ion energy in the order of hundreds of keV is demonstrated in this study. A specially designed ion irradiation facility was employed that enabled generation and irradiation with a highly accelerated and highly charged Ar ion beam. An ion-beam-induced amorphous layer on a silicon substrate can be selectively etched in hydrofluoric acid, whereas, a non-irradiated area is scarcely etched and, consequently, a concave structure can be fabricated on the irradiated area. To control the depth of the structure, parameters for dependence of the depth on ion irradiation were investigated. As a result, the depth of irradiated area can be controlled by the ion energy that is adjusted by the acceleration voltage and the ion charge. In addition, the etch resistance of the irradiated area increases with an increase in ion energy due to the crystalline layer formed on the surface. Simulation results reveal that the depth is strongly related to the defect distribution induced by ion irradiation. These results indicate the potential use of this method for novel three-dimensional lithography.