Antireflective structure imprinted on the surface of optical glass by SiC mold

An antireflective structure with two-dimensional 300-nm periodicity was fabricated on a phosphate glass surface using an imprinting process with a SiC mold. The optimized structure designed using RCWA calculation was a convex circular cone sharing the ridge line of adjacent cones. The SiC mold was fabricated using electron beam drawing and subsequent reactive ion etching with CHF₃ and O₂ gases. The glass’ surface reflectance was estimated as 0.2% at 530 nm wavelength, which was approximately 1/20 that of the optically polished surface.     

Total Synthesis of the Bicyclic Depsipeptide HDAC Inhibitors Spiruchostatins A and B, 5′′‐epi‐Spiruchostatin B,FK228 (FR901228) and Preliminary Evaluation of Their Biological Activity

The bicyclic depsipeptide histone deacetylase (HDAC) inhibitors spiruchostatins A and B, 5′′‐epi‐spiruchostatin B and FK228 were efficiently synthesized in a convergent and unified manner. The synthetic method involved the following crucial steps: i) a Julia–Kocienski olefination of a 1,3‐propanediol‐derived sulfone and a L ‐ or D ‐malic acid‐derived aldehyde to access the most synthetically challenging unit, (3S or 3R,4E)‐3‐hydroxy‐7‐mercaptohept‐4‐enoic acid, present in a D ‐alanine‐ or D ‐valine‐containing segment; ii) a condensation of a D ‐valine‐D ‐cysteine‐ or D ‐allo‐isoleucine‐D ‐cysteine‐containing segment with a D ‐alanine‐ or D ‐valine‐containing segment to directly assemble the corresponding seco‐acids; and iii) a macrocyclization of a seco‐acid using the Shiina method or the Mitsunobu method to construct the requisite 15‐ or 16‐membered macrolactone. The present synthesis has established the C5′′ stereochemistry of spiruchostatin B. In addition, HDAC inhibitory assay and the cell‐growth inhibition analysis of the synthesized depsipeptides determined the order of their potency and revealed some novel aspects of structure–activity relationships. It was also found that unnatural 5′′‐epi‐spiruchostatin B shows extremely high selectivity (ca. 1600‐fold) for class I HDAC1 (IC₅₀=2.4 nM ) over class II HDAC6 (IC₅₀=3900 nM ) with potent cell‐growth‐inhibitory activity at nanomolar levels of IC₅₀ values.     

Highly Elastic and Deformable Hydrogel Formed from Tetra‐arm Polymers

After decades of efforts by many researchers, we have succeeded in realizing a near‐ideal polymer network. This network, the Tetra network, is made by cross‐end‐coupling of tetra‐arm polymer modules. The mechanical energy dissipation was extremely low (tan δ ≈ 10⁻⁴). The macroscopic stress–strain relationship of the Tetra network was in good agreement with that of microscopic elastic blobs. The maximum breaking strength was extremely high (≥27 MPa). These results indicate that the Tetra network is closer to an ideal polymer network than any other conventional model networks. Because the Tetra network can be treated as uniformly packed elastic blobs, it should help apply the knowledge of single polymer chains seamlessly to the design of polymer materials and help further develop the theory of rubber elasticity.

     

Parallel two-step phase-shifting digital holography using polarization

We propose an optical implementation of a parallel two-step phase-shifting digital holography that utilizes a polarization technique. The implementation uses a phase-shifting array device consisting of a retarder array attached to an image sensor, and does not require the optical system to image the phase-shifting array device onto the image sensor required for the previously reported optical implementation of the parallel two-step phase-shifting digital holography. Then, the proposed implementation is essentially simple to align and compose. A preliminary experiment showed that the parallel two-step phase-shifting digital holography based on the proposed implementation can remove the conjugate image clinging to the image reconstructed by Fresnel transform alone with DC term suppression. Also, when the reconstruction distance was changed, the qualities of the reconstructed images were quantitatively evaluated by using normalized root-mean-square error. It was clarified that the proposed implementation was superior to other parallel phase-shifting digital holographies and Fresnel transform alone. Thus, the validity of the proposed implementation was confirmed.     

Evaluation of bone repair in the femur of rats submitted to laser therapy in different wavelengths: An image segmentation method of analysis

The aim of this study was to histologically assess the effect of laser therapy (LILT, 660 and 780 nm) on the repair of standardized bone defects on the femur of Wistar albinus rats. The sample was composed of 12 Wistar albinus young adult rats of both genders. Three randomized groups were studied: group I (control, n = 4), group II (LILT, 660 nm, n = 4), and group III (LILT, 780 nm, n = 4). Samples were prepared using a bone defect on the left-side femur surface of the animals, with a total dimension of approximately 3 mm³. Groups II and III were irradiated every 48 h from the second application, where the first dose was given immediately after surgery and the second application came 24 h after surgery. The irradiations were applied transcutaneously at four points around the wound for 14 days. At each point, a dose of 50 J/cm² (2 J) was given (s ～ 0.04 cm², 40 mW) and the total dose per session was 200 J/cm² (8 J). The sacrifices were made 15 days after surgery and the specimens were routinely processed to wax, serially cut, stained with an H&;E stain, and analyzed under light microscopy. The images were submitted to morphometric analysis using the image segmentation method using the K-means algorithm. The data obtained through the morphometric analysis were submitted to statistical analysis using the Tukey test. The results showed that the group treated with laser therapy in the infrared spectrum resulted in an increase in the repair of bone defects when compared with the group treated with the laser in the red spectrum and control group, which, in turn, had a very similar pattern of repair. A statistical significance (p < 0.01) was observed when comparing the results of group III and the results of Groups I and II. We concluded that the LILT in the infrared spectrum produced a positive biomodulation effect on the repair of bone defects in the femur of rats.     

Evaluating glycogen signal contamination in muscle by (13)C MRS of the liver

To evaluate the contamination of glycogen signal synthesized in skeletal muscle by that in the liver, long-term monitoring of over 7 h of in vivo [1-¹³C] glycogen synthesis/degradation at the right abdomen and left shoulder was achieved using a 3.0-T clinical MR system. ¹³C MR spectra without localization were obtained from five healthy volunteers before and after oral administration of 85 g of d-glucose, including 10 g of 99% [1-¹³C] glucose. In all volunteers, the relative signal intensities at the abdomen to those at shoulder were about two- to fivefold, and those of time-course changes at the abdomen and shoulder were dissimilar. It is considered that the quantity of muscle-synthesized glycogen signal at the abdomen is less than that at the shoulder because of the lesser muscle volume at the abdomen, and it may be less affected for evaluating glycogen synthesis/degradation in the liver even without localization pulses.     

SaxsMDView: a three‐dimensional graphics program for displaying force vectors

A new three‐dimensional graphics program, SaxsMDView, is described. The program performs a three‐dimensional graphical representation for protein molecules along with the force vector (or vector potential) applying to each atom. The displayed object can be rotated and translated in arbitrary directions by interactive mouse manipulation. While SaxsMDView was originally intended to visualize the result of SAXS_MD, a previously developed program based on the restrained molecular dynamics with small‐angle X‐ray scattering constraints, it can also be useful for graphical representation of other objects such as coarse‐grained molecular models reconstructed by ab initio modelling or solvent site‐dipole field vectors induced around the protein molecule. Some examples of the application of the program including the graphical analyses of the results with SAXS_MD are also presented.     

X-ray photoelectron spectroscopic studies on initial oxidation of iron and manganese mono-silicides

Initial oxidation of iron and manganese mono-silicides (FeSi and MnSi) surfaces was studied by X-ray photoelectron spectroscopy (XPS). Clean surfaces of these silicides were prepared by fracturing in an ultra high vacuum, and then the fractured surfaces were oxidized by exposing to high-purity oxygen at pressures up to 1.3 Pa. For the clean FeSi surface, positive chemical shifts of the Fe 2p_3/2 and Si 2p peaks from elemental Fe and Si were 0.5 eV and 0.1 eV, respectively. For the clean MnSi surface, a negative chemical shift of the Si 2p peak from elemental Si was 0.1 eV. Iron on the FeSi surface was oxidized at an oxygen pressure of 1.3 Pa, whereas the silicon was oxidized under the pressure of 1.3 × 10⁻⁶ Pa, indicating that oxidation of silicon occurred prior to that of iron. Manganese and silicon on the MnSi were simultaneously oxidized in the range from 1.3 × 10⁻⁶ Pa to 1.3 × 10⁻³ Pa; however, over the pressure of 1.3 Pa, the oxidation of manganese occurs prior to that of silicon. These oxidation behaviors at low oxygen pressures were similar to those of the FeSi and MnSi fractured in air.