Spectroscopic analysis for machining of inorganic materials with the harmonics of a Nd:YAG laser

An analytical method of wavelength optimization for machining of inorganic materials with different harmonics of a Nd:YAG laser is presented here. The explicit quantitative expression for the intrinsic absorptivity of material is provided. Combining the absorptivity of material with the conversion efficiency of laser apparatus, the optimum machining wavelength is estimated by calculating the absorption efficiency. Reflectivities, absorptivities, and absorption efficiencies are examined for semiconductors and insulators, and their optimum machining wavelengths are given in tables. The optimum machining wavelengths are in descending order from metals to semiconductors and then to insulators.     

Finishing of optical moulds to λ/20 by automated corrective polishing

Tungsten carbide is widely used to make replication moulds for small aspheric and freeform optics, like camera lenses. Since aspheric generation by grinding generally fails to reach ultra-precision criteria, a time efficient method for finishing moulds is needed. Using a 7-axis CNC polishing machine, an on-machine tool forming technique and compensation software were developed to correctively polish a plano WC surface of diameter 25 mm from a form error above λ to below λ/20 (29 nm P-V) in under 1 h, while reducing roughness to 1.0 nm Ra. This automatic method and tooling are applicable to aspheric and freeform moulds.     

Mechanism of self-association and filament capping by flagellar HAP2

HAP2 forms a capping structure, which binds very tightly to the distal end of flagellar filaments and still allows insertion of flagellin subunits below the cap by an unknown mechanism. Terminal regions of HAP2 from Salmonella typhimurium were found to be quickly degraded by various proteases, indicating that HAP2 also possesses disordered terminal regions like other axial proteins of bacterial flagellum. Removal of these portions by trypsin results in a fragment of 40 kDa (HP40), which lacks 42 NH2-terminal and 51 COOH-terminal residues. HAP2 in solution readily associates into a decameric structure without any significant population of intermediate oligomeric forms. The HP40 fragments, however, do not form decamers, while they can assemble into pentamers, as revealed by chemical cross-linking and analytical ultracentrifugation. Decameric HAP2 also dissociates into pentamers and smaller oligomers upon a heat induced conformational transition around 36 degreesC. While the highly mobile terminal regions are immobilized in decameric HAP2 complexes, they are still largely disordered in the pentameric state. These results demonstrate that the intersubunit interactions within the pentamers are mainly through the HP40 portions, whereas the terminal regions are responsible for association of pentamers into decameric complexes. Several observations indicate that HAP2 performs its capping function as a pentamer. We suggest that binding of the pentameric HAP2 cap to the filament is mediated by the highly flexible terminal regions. Indeed, HP40 fragments are unable to cap the end of filaments, while removal of about 30 residues from both terminal regions of HAP2 results in a highly reduced capping ability. A model is presented to explain the molecular mechanism of capping, in which conformational entropy in the disordered terminal regions moderates the otherwise too tight HAP2-filament interactions to allow insertion of flagellin subunits below the cap.     

Tumor imaging with technetium-99m-DTPA encapsulated in RES-avoiding liposomes

For passive targeting of liposomes to tumor tissues, we earlier developed reticuloendothelial system (RES)-avoiding liposomes modified with a uronic acid derivative, palmityl-D-glucuronide (PGlcUA). In the present study, we encapsulated technetium-99m (99mTc)-diethylenetriaminepentaacetic acid (DTPA) in PGlcUA-liposomes (dipalmitoylphosphatidylcholine:cholesterol:PGlcUA = 40:40:20 as a molar ratio) and studied the biodistribution of the liposomes in tumor-bearing mice. 99mTc-DTPA encapsulated in liposomes effectively accumulated in tumor tissues after intravenous administration. Corresponding to these results, tumor was strongly imaged by a gamma-camera when 99mTc-DTPA-encapsulated PGlcUA-liposomes were used.     

Hepatoprotective principles of Swertia japonica Makino on D-galactosamine/lipopolysaccharide-induced liver injury in mice

The n-BuOH extract of Swertia japonica showed a significant hepatoprotective effect on D-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced liver injury in mice. The activity-guided fractionation led to the isolation of a new tetrahydroxanthone derivative, tetrahydroswertianolin (1), as well as two known iridoids, gentiopicroside (2) and sweroside (3). Their structures were elucidated by spectroscopic methods and chemical reactions. Of the three compounds, 2 and 3 possessed mild hepatoprotective activity at a dose range of 25-50 mg/kg, whereas, 1 exhibited potent activity in a dose-dependent manner. The hepatoprotective effect of tetrahydroswertianolin (1) was stronger than that of glycyrrhizin which was used as a positive control.     

Chiba Scan Delay Fault Testing with Short Test Application Time

Delay fault testing using a scan design facilitating two-pattern testing, called Chiba scan testing, requires a long test application time (TAT) compared with well-known delay fault testing. This paper presents an improved Chiba scan testing with short TAT by providing a test compaction. In addition, it presents a test generation for the Chiba scan testing improved by the proposed compaction. Evaluation shows that, for robust path delay fault testing on ISCAS89/ ADDENDUM benchmark circuits, the TAT of Chiba scan testing with the proposed compaction is, on average, 47% and 21% shorter than that of Chiba scan testing without test compaction and that of enhanced scan testing with the conventional test compaction, respectively. In addition, in many cases, the fault coverage of the proposed testing is higher than that of launch-off-capture (LoC) and launch-off-shift (LoS) testing with the same TAT.