Optical resolution of n-butyl d- and l-lactates using immobilized lipase catalyst

n-Butyl d- and l-lactates (BuDLa and BuLLa) were incubated with immobilized lipase. ¹H-NMR showed that BuDLa reacted to oligomers, while BuLLa did not react. A mixture containing 90.4% of BuLLa and 9.6% of BuDLa was incubated with the enzyme for 72 h, then distilled. The purity of BuLLa increased to 98.6%.     

Programmable self-assembly of metal ions inside artificial DNA duplexes

The ultimate bottom-up approach for the construction of functional nanosystems requires the precise arrangement of atoms and molecules in three dimensions. DNA is currently one of the most prominent molecules able to self-assemble into complex networks and is therefore regarded as the 'silicon of the nano-world'. Metals and metal ions, in contrast, are the atomic building-blocks needed in such materials to establish functions such as electrical conductivity or magnetism. Here we report a new concept, which efficiently combines metal ions and DNA. The DNA structure is used as a matrix to program robustly the complexation of different metal ions under precise control with regard to element, number and composition.     

Temperature phase-matching properties for harmonic generation in GdCa4O(BO3)3 and Gd(x)Y(1-x)Ca4O(BO3)3

GdCa4O(BO3)3 has been found to have phase-matching points where the temperature variations of the phase-matching angles become zero for type-1 sum-frequency generation in the zx plane. We also found that the temperature sensitivities of the phase-matching conditions in the zx plane are different along the phi = 0 degrees and phi = 180 degrees directions in this material. In addition, the thermo-optic dispersion formula of this material that reproduces the temperature phase-matching properties of GdCa4O(BO3)3 and Gd(x)Y(1-x)Ca4O(BO3)3 is presented.     

Regional difference of water content in human skin studied by diffuse-reflectance near-infrared spectroscopy: consideration of measurement depth

Diffuse reflectance (DF) spectra in the 1250-2500 nm region were measured in vivo for the skin of the forehead, cheek, jaw, elbow, volar forearm, palm, knee, and heel of seven healthy volunteers, using a Fourier transform near-infrared (FT-NIR) spectrophotometer with a fiber-optic probe. Apparent regional differences of water content in the skin, as estimated from the diffuse reflectance NIR spectra, are discussed in relation to the influence of measurement depth. The NIR spectra were collected with or without a 300 microm gap between the fiber-optic probe and the skin surface. For comparison, in vitro NIR spectra of stratum corneum sheets equilibrated at 41, 50, 63, and 81% relative humidity, at 25 degrees C, were also obtained. There was a difference in the ratio of the two water bands centered near 1450 nm and 1900 nm between the contact and non-contact measurements. In addition, regional differences of water content calculated from the peak height of the 1900 nm water band, which was normalized to the peak height of the 2175 nm amide band, were compared. The results of Monte Carlo simulation indicated that the apparent regional differences arise at least in part from differences in the measurement depth due to differences in specular reflection at the skin surface and in the thickness of the stratum corneum.     

Detection and activity of iodine-131 in brown algae collected in the Japanese coastal areas

Iodine-131 (physical half-life: 8.04 days) was detected in brown algae collected off the Japanese coast. Brown algae have been extensively used as bioindicators for radioiodine because of their ability to accumulate radionuclides in high concentration factors. The maximum measured specific activity of ¹³¹I in brown algae was 0.37 ± 0.010 Bq/kg-wet. Cesium-137 was also detected in all brown algal samples used in this study. There was no correlation between specific activities of ¹³¹I and ¹³⁷Cs in these seaweeds. The specific activity of ¹³⁷Cs ranged from 0.0034 ± 0.00075 to 0.090 ± 0.014 Bq/kg-wet. Low specific activity and minimal variability of ¹³⁷Cs in brown algae indicated that past nuclear weapon tests were the source of ¹³⁷Cs. Although nuclear power stations and nuclear fuel reprocessing plants are known to be pollution sources of ¹³¹I, there was no relationship between the sites where ¹³¹I was detected and the locations of nuclear power facilities. Most of the sites where ¹³¹I was detected were near big cities with large populations. Iodine-131 is frequently used in diagnostic and therapeutic nuclear medicine. On the basis of the results, we suggest that the likely pollution source of ¹³¹I, detected in brown seaweeds, is not nuclear power facilities, but nuclear medicine procedures.     

Potential use of only Yb2O3 in producing dense Si3N4 ceramics with high thermal conductivity by gas pressure sintering

Yb₂O₃ is an efficient sintering additive for enhancing not only thermal conductivity but also the high-temperature mechanical properties of Si₃N₄ ceramics. Here we report the fabrication of dense Si₃N₄ ceramics with high thermal conductivity by the gas pressure sintering of α-Si₃N₄ powder compacts, using only Yb₂O₃ as an additive, at 1900 °C under a nitrogen pressure of 1 MPa. The effects of Yb₂O₃ content, sample packing condition and sintering time on the densification, microstructure and thermal conductivity were investigated. Curves of the density plotted against the Yb₂O₃ content exhibited a characteristic ‘N’ shape with a local minimum at 3 mol% Yb₂O₃ and nearly complete densification below and above this concentration. The effects of the sample packing condition on the densification, microstructure and thermal conductivity strongly depended on the Yb₂O₃ content. The embedded condition led to more complete densification but also to a decrease in thermal conductivity from 119 to 94 W m^-1 K⁻¹ upon 1 mol% Yb₂O₃ addition. The sample packing condition had little effect on the density and thermal conductivity (102–106 W m⁻¹ K⁻¹) at 7 mol% Yb₂O₃. The thermal conductivity value was strongly related to the microstructure.     

KOMPEITO,an Atypical Arabidopsis Rhomboid-Related Gene,Is Required for Callose Accumulation and Pollen Wall Development

Fertilization is a key event for sexually reproducing plants. Pollen–stigma adhesion, which is the first step in male–female interaction during fertilization, requires proper pollen wall patterning. Callose, which is a β-1.3-glucan, is an essential polysaccharide that is required for pollen development and pollen wall formation. Mutations in CALLOSE SYNTHASE 5 (CalS5) disrupt male meiotic callose accumulation; however, how CalS5 activity and callose synthesis are regulated is not fully understood. In this paper, we report the isolation of a kompeito-1 (kom-1) mutant defective in pollen wall patterning and pollen–stigma adhesion in Arabidopsis thaliana. Callose was not accumulated in kom-1 meiocytes or microspores, which was very similar to the cals5 mutant. The KOM gene encoded a member of a subclass of Rhomboid serine protease proteins that lacked active site residues. KOM was localized to the Golgi apparatus, and both KOM and CalS5 genes were highly expressed in meiocytes. A 220 kDa CalS5 protein was detected in wild-type (Col-0) floral buds but was dramatically reduced in kom-1. These results suggested that KOM was required for CalS5 protein accumulation, leading to the regulation of meiocyte-specific callose accumulation and pollen wall formation.     

Fluorescence Imaging Using Enzyme-Activatable Probes for Detecting Diabetic Kidney Disease and Glomerular Diseases

A clear identification of the etiology of glomerular disease is essential in patients with diabetes. Renal biopsy is the gold standard for assessing the underlying nephrotic pathology; however, it has the risk for potential complications. Here, we aimed to investigate the feasibility of urinary fluorescence imaging using an enzyme-activatable probe for differentiating diabetic kidney disease and the other glomerular diseases. Hydroxymethyl rhodamine green (HMRG)-based fluorescent probes targeting gamma-glutamyl transpeptidase (GGT) and dipeptidyl-peptidase (DPP) were used. Urinary fluorescence was compared between groups which were classified by their histopathological diagnoses (diabetic kidney disease, glomerulonephritis, and nephrosclerosis) as obtained by ultrasound-guided renal biopsy. Urinary fluorescence was significantly stronger in patients with diabetic kidney disease compared to those with glomerulonephritis/nephrosclerosis after DPP-HMRG, whereas it was stronger in patients with nephrosclerosis than in patients with glomerulonephritis after GGT-HMRG. Subgroup analyses of the fluorescence performed for patients with diabetes showed consistent results. Urinary fluorescence imaging using enzyme-activatable fluorescence probes thus represents a potential noninvasive assessment technique for kidney diseases in patients with diabetes.     

Involvement of a Cluster of Basic Amino Acids in Phosphorylation-Dependent Functional Repression of the Ceramide Transport Protein CERT

Ceramide transport protein (CERT) mediates ceramide transfer from the endoplasmic reticulum to the Golgi for sphingomyelin (SM) biosynthesis. CERT is inactivated by multiple phosphorylation at the serine-repeat motif (SRM), and mutations that impair the SRM phosphorylation are associated with a group of inherited intellectual disorders in humans. It has been suggested that the N-terminal phosphatidylinositol 4-monophosphate [PtdIns(4)P] binding domain and the C-terminal ceramide-transfer domain of CERT physically interfere with each other in the SRM phosphorylated state, thereby repressing the function of CERT; however, it remains unclear which regions in CERT are involved in the SRM phosphorylation-dependent repression of CERT. Here, we identified a previously uncharacterized cluster of lysine/arginine residues that were predicted to be located on the outer surface of a probable coiled-coil fold in CERT. Substitutions of the basic amino acids in the cluster with alanine released the SRM-dependent repression of CERT activities, i.e., the synthesis of SM, PtdIns(4)P-binding, vesicle-associated membrane protein-associated protein (VAP) binding, ceramide-transfer activity, and localization to the Golgi, although the effect on SM synthesis activity was only partially compromised by the alanine substitutions, which moderately destabilized the trimeric status of CERT. These results suggest that the basic amino acid cluster in the coiled-coil region is involved in the regulation of CERT function.     

Numerical experiment of measurement-integrated simulation to reproduce turbulent flows with feedback loop to dynamically compensate the solution using real flow information

Reproduction of the exact structure of real turbulent flows is crucial in many applications. Four Dimensional variation (4D-VAR) is widely used in numerical weather forecasting, but it requires huge computational power to repeatedly solve flow dynamics and its adjoint, and, therefore, is not suitable to apply to problems of real-time flow reproduction such as feedback flow control. Kalman filter and observer, in which numerical solution converges to the real state asymptotically by means of the feedback signal proportional to the difference between the calculated state and the real state, requiring much less computational load than the variational method, are potential candidates to solve the problem. By comparing Kalman filter and observer, the latter has simpler structure retaining essential part of the state estimation. This study deals with a special type of observer, or measurement-integrated simulation (MI simulation), in which a SIMPLER-based flow solver is used as the mathematical model of the system in place of approximate small dimensional linear differential equations usually used in observers. Reproduction of the exact structure of a turbulent flow was investigated by a MI simulation. A numerical experiment was performed for a fully developed turbulent flow in a pipe with a square cross section. The MI simulation was performed with the feedback from the standard solution in the flow domain for the cases using: (1) all velocity components at all grid points, (2) partial velocity components at all grid points, or (3) all velocity components at partial grid points. Convergence of the MI simulation to the standard solution was investigated using the steady error norm for the convergent state and the time constant for the transient state. The result of the MI simulation using all the velocity information exponentially converges to the standard solution with a steady state error reduced from that of the ordinary simulation in a range of the feedback gain. Decreasing the feedback gain reduces the effect of feedback, and a feedback gain which is too large destabilizes the closed loop system, resulting in large error. The time constant decreases almost inversely proportional to the feedback gain as long as the feedback system is stable. For the MI simulation with the feedback using limited information, feedback using two velocity components by omitting one transverse velocity component showed a good result, although the other results were not satisfactory. For the MI simulation with the feedback using limited grid points, the result of the MI simulation applying the feedback at the grid points on every 20th plane in the x₁ direction was almost the same as that using all grid points at some feedback gain, while the result with the feedback on the planes skipped in the x₂ direction requires 10 times more planes to achieve the same reduction rate.