Factors determining the stability, resolution, and precision of a conventional Raman spectrometer

We verified the performance of a conventional Raman spectrometer, which is composed of a 30 cm single polychromator, a Si based charge-coupled device (CCD) camera, and a holographic supernotch filter. For that purpose, the time change of the peak positions of Raman spectra of naphthalene and fluorescence spectra of ruby (Cr-doped Al(2)O(3)) were monitored continually. A time-dependent deviation composed of two components was observed: a monotonous drift up to 0.4 cm(-1) and a periodic oscillation with a range of 0.15 cm(-1). The former component was stabilized at approximately 2000 s after the CCD detector was cooled, indicating that incomplete refrigeration of the CCD detector induced the drift. The latter component synchronized with the periodic oscillation of the room temperature, indicating that thermal expansion or contraction of the whole apparatus induced this oscillation. The implemental deviation is reduced when measurements are conducted using a sufficiently cooled CCD detector at a constant room temperature. Moreover, the effect of the room temperature oscillation is lowered in a spectrum acquired over a duration that is longer than one cycle of this oscillation. Applying the least squares fitting method to carefully measured spectra enhanced the precision of the determination of the peak position to 0.05 cm(-1) using the spectrometer with pixel resolution of 1.5 cm(-1).     

Dietary Marine-Derived Tocopherol has a Higher Biological Availability in Mice Relative to Alpha-Tocopherol

The biologic availability of two kinds of tocomonoenols, marine-derived tocopherol (MDT) and α-tocomonoenol, was investigated in ICR mice. Vitamin E-deficient ICR mice were fed MDT and α-tocomonoenol together with α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol, and storage in liver, spleen, lung, and brain was quantified using reverse-phase high-performance liquid chromatography. The vitamin E relative biologic availability (VE-RBA) in liver was 100 for α-tocopherol, 26 ± 3 for β-tocopherol, 4 ± 2 for γ-tocopherol, not detected for δ-tocopherol, 49 ± 6 for MDT, and 30 ± 7 for α-tocomonoenol. The VE-RBA in brain was 100 for α-tocopherol, 5 ± 2 for β-tocopherol, not detected for γ-tocopherol and δ-tocopherol, 8 ± 1 for MDT, and 4 ± 1 for α-tocomonoenol. Tocopherols and tocomonoenols did not accumulate in the spleen or lung. MDT and α-tocomonoenol had high VE-RBA values. The VE-RBA value for MDT was much higher than that for β-tocopherol.     

The High-Resolution X-Ray Microcalorimeter Spectrometer, SXS, on Astro-H

The science and an overview of the Soft X-ray Spectrometer onboard the STRO-H mission are presented. The SXS consists of X-ray focusing mirrors and a microcalorimeter array and is developed by international collaboration lead by JAXA and NASA with European participation. The detector is a 6×6 format microcalorimeter array operated at a cryogenic temperature of 50 mK and covers a 3′×3′ field of view of the X-ray telescope of 5.6 m focal length. We expect an energy resolution better than 7 eV (FWHM, requirement) with a goal of 4 eV. The effective area of the instrument will be 225 cm² at 7 keV; by a factor of about two larger than that of the X-ray microcalorimeter on board Suzaku. One of the main scientific objectives of the SXS is to investigate turbulent and/or macroscopic motions of hot gas in clusters of galaxies.     

Bacterial contamination in an egg-breaking factory and its control

From January to November, 2003, bacterial contamination was surveyed in a small egg-breaking factory that produced non pasteurized liquid egg. Test egg samples were taken at various stages of the egg processing operation. Salmonella Enteritidis was isolated from liquid egg yolk and liquid egg white on October, but was not found in any other samples (50 liquid egg samples, 21 containers and 94 attached production facilities and gloves). The data suggest that the contamination rate (3.8%) is lower than those reported previously. Levels of bacterial standard plate counts, gram-positive bacterial counts and gram-negative bacterial counts were in the ranges of 2 to 5 log CFU/g, 2 to 3 log CFU/g, 2 to 5 log CFU/g, respectively. Liquid egg containers returned from customers was contaminated with bacteria at the level of 8 log CFU per container. However, washing and application of a sanitizer containing sodium hypochlorite reduced the bacterial counts.     

Effect of diacylglycerol on the development of impaired glucose tolerance in sucrose-fed rats

The effects of DAG oil and TAG oil on impaired glucose tolerance in rats that were fed a diet containing high levels of sucrose were compared. Male Wistar rats (8 wk old and 32 wk old) were fed either high-sucrose (57.5% sucrose w/w) or control diets containing either 10% (w/w) DAG or TAG oil with a similar FA composition for 48 wk in 8-wk-old rats and for 24 wk in 32-wk-old rats. Plasma lipids, the size of the islets of Langerhans, and insulin, glucose, and adipocytokine levels were measured. An oral glucose tolerance test (OGTT) was carried out during the study period. For rats in both age groups that were fed a high-sucrose diet, the DAG oil group had lower plasma glucose and insulin response in an OGTT, and lower homeostasis model assessment-R levels, than the TAG oil group. Furthermore, in 8-wk-old rats that were fed a high-sucrose diet, the DAG oil group accumulated less visceral fat and showed decreases of plasma adiponectin and suppressed increases of plasma insulin, leptin, and the size of islet of Langerhans compared with the TAG oil group. No difference in the OGTT was found between the DAG and TAG oil groups in either age group of rats fed a control diet. In conclusion, these results suggest that DAG oil ingestion prevents the high-sucrose-diet-induced development of impaired glucose tolerance compared with TAG oil ingestion.     

Isolation and characterization of murine hepatocytes following collagenase infusion into left ventricle of heart

A method for obtaining mouse hepatocytes by infusing collagenase solution into the left ventricle was established. This technique was shown to be equivalent to the intra-portal infusion method and more practical, especially in postnatal mice with a small body size.     

High spatial resolution photoluminescence and Raman spectroscopic measurements of a natural polycrystalline diamond, carbonado

Photoluminescence and Raman spectra with high spatial resolution (< 1 μm) were observed on a natural polycrystalline diamond, carbonado. The studied sample is from Central African Republic (CAR) and was polished to optical grade. In addition to observation by optical microscopy, Scanning Near-field Optical Microscopy (SNOM) was applied for spectral and topographic analysis at high spatial resolution less than 300 nm. Mapping of the photoluminescence intensity of carbonado using SNOM indicated that the emission intensity was lower at the grain boundaries and the fringe of pores of carbonado revealed weakest intensity. Photoluminescence spectra of carbonado observed using optical microscopy and SNOM comprised three sharp bands at 504, 575 and 638 nm with their side bands and the color of photoluminescence changed according to its location. Raman spectra measured using optical microscopy revealed that the residual stress locally exists underneath the sample surface and the maximum stress value observed in this study was 0.72 GPa. Additionally, pressure dependence of the 575 nm band was measured using a diamond anvil cell up to 3.5 GPa. The 575 nm band shifted linearly to a lower wavelength with increasing pressure with a gradient of − 0.57 GPa/nm. This relationship was applied to estimations of the stress distribution of carbonados using SNOM. No significant changes in peak positions of photoluminescence spectra were detected on the surface of carbonados. This result suggests that carbonado is well sintered and that the residual stress of carbonado exists locally inside the crystal.     

Chromosomal DNA patterns and gene stability of Pichia pastoris

We have clearly resolved four chromosomal bands from four Pichia pastoris (Komagataella pastoris) strains by using contour-clamped homogeneous electric field gel electrophoresis. The size of the P. pastoris chromosomal bands ranged from 1·7 Mb to 3·5 Mb and total genome size was estimated to be 9·5 Mb to 9·8 Mb; however, chromosome-length polymorphisms existed among four strains. Thirteen cloned genes isolated from strain GTS115 were assigned to the separated chromosomes, revealing that different hybridization patterns were observed in the AOX2 and URA3 genes among strains. P. pastoris is frequently used as an efficient host for heterologous gene expressions. We analysed chromosomal stability of strain GTS115-derived recombinant cell expressing human serum albumin during serial cultivation under the condition of vegetative and non-selective growth. No chromosomal rearrangements were observed and the expression constructs integrated into the his4 locus on chromosome I were very stable even at 83 generations, suggesting that stable expression would be carried out even in large-scale fermentation. © 1998 John Wiley & Sons, Ltd.     

Dynamics of antioxidant action of vitamin E

Vitamin E is the major lipophilic, radical-scavenging antioxidant in vivo and protects humans from the oxidative stress mediated by active oxygen and nitrogen species. The mechanisms of the inhibition of oxidation by vitamin E in vitro are now fairly well understood, but the dynamics of antioxidant action of vitamin E in vivo have not been well elucidated yet, primarily because of the inherent heterogeneity of biological systems. In this Account, the factors which determine the antioxidant capacity of vitamin E are discussed, and the importance of its localization and mobility in the membranes and lipoproteins is emphasized.