Observation of Q-spoiling ef fects on the resonance modes from a noncircularly deformed liquid jet

Spectral changes in fluorescence and lasing spectra were observed from a noncircularly deformed ink-doped ethanol jet, which was induced by a lateral gas flow. The distortion parameter was determined from the analysis of diffraction patterns to be as much as ~10%. Q -spoiling effects were clearly observed in the appearance of high- Q (~10(7)) modes in fluorescence and their disappearance in lasing. From the behavior of resonance modes, we concluded that the effective Q does not decrease so rapidly as predicted by the relation obtained from the ray-optics model. We also found that the signals leak out, with a wide angular spreading, mainly from near the boundary of the major axis, even for a large distortion parameter.     

Preparation and characterization of N‐methyl‐substituted polyurethane

We prepared N‐methyl‐substituted polyurethanes with different substitution degrees from sodium hydride, methyl p‐toluene sulfonate, and polyether–polyurethane containing poly(oxytetramethylene) glycol, 4,4′‐diphenylmethane diisocyanate, and 1,4‐butanediol. The chemical structures were characterized with Fourier transform infrared and ¹H NMR. To investigate the effects of the N‐substitution degree on the morphology, thermal stability, and mechanical properties, we used differential scanning calorimetry, thermogravimetric analysis, and a universal testing machine. As the substitution degree increased, the new free (1708 cm^?1) and bonded (1650 cm^?1) carbonyl peaks increased. There was no bonded carbonyl peak in fully substituted polyurethane because the urethane groups had no hydrogen. At a small substitution degree, we observed a slight increase in the glass‐transition temperature and decrease in the endotherms of soft‐segment and hard‐segment domains due to the decrease in the hard‐segment domain and the increase in the urethane groups in the soft‐segment domain. The hard‐segment domain decreased and then disappeared as the N‐methyl substitution degree increased. These changes in the morphology resulted (1) in decreased modulus and tensile strength for the films because of the decrease in physical crosslinking points and (2) improved thermal stability as the substitution degree increased. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4077–4083, 2002     

Proteomic Evaluation of Biomarkers to Determine the Postmortem Interval

Proteomics separates and analyzes proteins for investigation at the cellular level in regard to disease processing by analyzing the proteins’ expression, function, structure, post-translational modification, and protein–protein interaction. In general forensic investigations, the postmortem interval was evaluated by measuring changes in body temperature after death, along with forensic entomological knowledge. These investigations may be restrictive and subjective because of external factors. The objectives of this study are to sort biomarker candidates and develop a direct postmortem-interval characterization method using proteomics through analyzing and tracking down proteins in the deceased that change in accordance with the postmortem interval. The liver and heart tissues of rats were collected for protein extraction in the 24-h interval following death, and two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis was conducted based on the isoelectric point and the molecular weight for separation. To validate protein spot changes on the gel, the stained electrophoresis gels were scanned and converted to digital images. Through image analysis, 14 liver proteins and 12 heart proteins were sorted and classified into four groups based on pattern changes. These proteins containing spots were extracted from the gel and analyzed by high-performance liquid chromatography with tandem mass spectrometry. Finally, 26 protein postmortem-interval relevant biomarker candidates were identified using software. Some of the proteins were muscle proteins while others were oxidation-related proteins. This study presents a new approach to the postmortem-interval research using proteomics and could be substituted for postmortem-interval evaluation.     

Iron Oxide Photoelectrode with Multidimensional Architecture for Highly Efficient Photoelectrochemical Water Splitting

Nanostructured metal oxide semiconductors have shown outstanding performances in photoelectrochemical (PEC) water splitting, but limitations in light harvesting and charge collection have necessitated further advances in photoelectrode design. Herein, we propose anodized Fe foams (AFFs) with multidimensional nano/micro-architectures as a highly efficient photoelectrode for PEC water splitting. Fe foams fabricated by freeze-casting and sintering were electrochemically anodized and directly used as photoanodes. We verified the superiority of our design concept by achieving an unprecedented photocurrent density in PEC water splitting over 5 mA cm⁻² before the dark current onset, which originated from the large surface area and low electrical resistance of the AFFs. A photocurrent of over 6.8 mA cm⁻² and an accordingly high incident photon-to-current efficiency of over 50 % at 400 nm were achieved with incorporation of Co oxygen evolution catalysts. In addition, research opportunities for further advances by structual and compositional modifications are discussed, which can resolve the low fill factoring behavior and improve the overall performance.     

Reconstructive extremity dosimetry with 3D scanned hand model in MCNPX

We present a simulation method that can create accurate virtual models of hand with arbitrarily curved surfaces and perform distortion-free MCNPX simulations. Generally, MCNPX simulations of objects with arbitrarily curved surfaces are performed through voxelization. In this study, a polygon model is tetrahedralized by TetGen for the construction of the MCNPX geometry to be distortion-free. Then, dose estimation was successfully performed after converting the virtual model into an MCNPX input. A voxelized model was constructed for comparison purposes. The dose estimation functions of the two models were found to be similar, showing a similar amount of computing time by using the mesh tally option with 2e7 histories.     

1,1-Insertion of substituted alkynes into the Ir-O bond of η-carboxylato iridium complexes

Alkyl-carbonyl-iridium [Ir(CH₃)(CO)(η²-O₂CR′)(PPh₃)₂]⁺ (1, R′ = CH₃, Ph, p-C₆H₄CH₃) react with alkynes (RCCH; R = Ph, p-C₆H₄CH₃) in the presence of NEt₃ to give acyl-alkynyl-iridium Ir(C(O)CH₃)(-CCR)(η²-O₂CR′)(PPh₃)₂ (4) which further react with RCCH to give alkyl-carbonyl-cis-bis(alkynyl) iridium Ir(CH₃)(CO)(CCR)₂(PPh₃)₂ (5). cis-Bis(alkenyl)iridium complexes, Ir(-CHCH₂)₂(η²-O₂CCH₃)(PPh₃)₂ (6) and (η²-O₂CCH₃)(PPh₃)₂ (7) react with substituted alkynes RCCH (R = Ph, p-C₆H₄CH₃, cyclohex-1-enyl) to give cis-bis(alkynyl) Ir(CCR)₂(η²-O₂CCH₃)(PPh₃)₂ (9) that further react with RCCH to undergo the alkyne insertion reaction into the Ir-O bond to produce iridacycles containing vinyl acetate ligands, (-CCR)₂(PPh₃)₂ (8).     

Performance improvement of a Kα source by a high-resolution thin-layer-graphite spectrometer and a polycapillary lens

A tabletop, short-pulse laser-based hard X-ray (Kα) source equipped with an advanced X-ray optics and dedicated for high-resolution spectroscopy and time-resolved diffraction is described. Operation of the source together with a high-resolution spectrometer containing a large-aperture highly annealed pyrolytic graphite gave a resolution E/ΔE of ~1,800 for the spectral range around Kα line of Cu. The estimated total flux of the 8.05-keV photons was equal to 5.9 × 10¹⁰ ph/s in 4π sr. Performance boost of the source caused by X-ray optics relied on the significant increase in the Cu-Kα photon flux on both, the sample (4.7 × 10⁶ ph/s) and the detector (3.4 × 10³ ph/s). A spectral brightness of 1.4 × 10⁷ ph/s/mm²/mrad² was derived from the source parameters for the Kα line. Better performance due to high collecting power and reflectivity of the spectrometer enabled application of the cross-correlation technique with an Ni foil. An upper bound of emission duration of 323 ± 47 fs was obtained in this measurement. X-ray absorption near-edge spectroscopy on an Ni sample with an acquisition time of only 15 min confirmed the increased capability of the setup also for continuous spectrum (bremsstrahlung).