Confirmation of Disorder α Form of Poly(L-lactic acid) by the X-ray Fiber Pattern and Polarized IR/Raman Spectra Measured for Uniaxially-Oriented Samples

In the present research, we report for the first time the X-ray fiber pattern and polarized IR/Raman spectra taken for the uniaxially oriented disorder α form of PLLA, which can confirm the existence of the disorder PLLA α form (α′-form) and provide some new insight on the structural difference between the order and disorder α forms.     

Post‐synthetic Spin‐Labeling of RNA through Click Chemistry for PELDOR Measurements

Site‐directed spin labeling of RNA based on click chemistry is used in combination with pulsed electron‐electron double resonance (PELDOR) to benchmark a nitroxide spin label, called here d? . We compare this approach with another established method that employs the rigid spin label Çm for RNA labeling. By using CD spectroscopy, thermal denaturation measurements, CW‐EPR as well as PELDOR we analyzed and compared the influence of d? and Çm on a self‐complementary RNA duplex. Our results demonstrate that the conformational diversity of d? is significantly reduced near the freezing temperature of a phosphate buffer, resulting in strongly orientation‐selective PELDOR time traces of the d? ‐labeled RNA duplex.     

Preparation of poly(acrylic acid)‐b‐polystyrene by two‐step atom transfer radical polymerization in supercritical carbon dioxide

It is known that it is difficult to polymerize carboxylic acid‐based monomer by atom transfer radical polymerization (ATRP) in polar solvents due to the protonation of ligand caused by acidic dissociation of the monomer. In this study, precipitation reverse ATRP of acrylic acid (AA) was carried out in supercritical carbon dioxide (scCO₂), which is a nonpolar solvent to dissolve transition metal complexes, at 30 MPa and 45 °C. The polymerization proceeded smoothly and the conversion reached 86% for 3 h. After vending of scCO₂, a dry poly(acrylic acid) (PAA) powder was obtained. Weight‐average molecular weight and polydispersity of the methylated PAA, which were measured by gel‐permeation chromatography after methyl esterification, were 3.5 × 10⁴ and 2.07, respectively, indicating that the precipitation reverse ATRP proceeded with a bad control manner. However, chain extension of the methylated PAA with styrene was possible by ATRP in a bulk system. Moreover, PAA‐b‐polystyrene was successfully prepared in scCO₂ directly by two‐step ATRP, although its molecular weight distribution was broad. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Complexation of Terbium Ion with the Copolymer of Acrylic Acid and Acrylamide Grafted onto Polyethylene

Acrylic acid (AA) and acrylamide (AAm) were graft copolymerized onto polyethylene powder by the preirradiation method. The PE powder grafted with both AA and AAm (PE-g-(AA-co-AAm)) rapidly adsorbed Tb ion with an efficiency higher than did PE powder grafted with AA (PE-g-AA). The complex formation constant of Tb ion with PE-g-(AA-co-AAm) was larger than that with PE-g-AA because the introduction of the acrylamide part decreased the steric hindrance for complexation between Tb and the carboxyl group of the graft chains. Tb ion was efficiently separated from transition metal ions, such as Co, upon passage of a solution through a column packed with PE-g-(AA-co-AAm).     

Challenge of advanced low temperature fuel cells based on high degree of freedom of group 4 and 5 metal oxides

To obtain an ideal electrocatalysts for hydrogen fuel cells, we investigated group 4 and 5 oxide-based compounds because of their high degree of freedom. First-principles calculations revealed that oxide surfaces such as those of titanium oxide could break down the universal scaling to achieve the ideal state of the oxygen reduction reaction. We experimentally clarified that the active sites were oxygen vacancies for tantalum and zirconium oxides, in addition to doped foreign elements and crystalline structures for titanium oxide. We successfully demonstrated that precious metal-free and carbon-free oxide-based cathodes have high quality active sites and superior durability in 0.1 M sulfuric acid at 80°C. Our strategy was developed as follows: (1) Active sites are created on the oxide surface by modifying the crystalline structure and electronic states and (2) electrons participating in the oxygen reduction reaction are supplied by nanosized oxide particles and oxide films through the tunneling effect of electrons.     

Thermal activation of KF/alumina catalyst for double bond isomerization and Michael addition

KF/alumina catalyst exhibits activity for double bond isomerization of 1-pentene at 273 K when pretreatedin vacuo in the temperature range 573–673 K, while the activity for Michael addition of nitromethane to butene-2-one does not change much with the pretreatment temperature.     

M-Mode Color Doppler Ultrasonic Imaging of Vertical Tongue Movement During Articulatory Movement

To observe and estimate the movement of the tongue, ultrasonic investigation is the most harmless real-time monitoring procedure for analyzing articulatory movements. Color Doppler ultrasonic imaging is special in that it can only sample a moving target, and it can indicate the velocity and direction of the target by color and brightness in real time. This study assessed and demonstrated the validity of M-mode color Doppler ultrasonic imaging to observe the movements of the tongue during syllable repetition tasks performed by normal subjects and dysarthric patients, those affected by amyotrophic lateral sclerosis, cerebellar ataxia, Parkinsonism, and polymyopathy. When the transducer was set below the jaw, upward movement was indicated by a blue signal and downward movement was indicated by a red one on the screen of the ultrasound machine. We also measured the velocity of the tongue by contrast scale classified by 15 degrees. Thus, we could observe vertical tongue movement by a color-coded pattern after quantitative analysis. The Doppler signal patterns of normal subjects were verified by simultaneous video x-ray fluorography recordings. The findings for dysarthric patients corresponded well with previously reported features analyzed by other methods. Therefore, color Doppler ultrasonic imaging of the tongue is a useful procedure to researchers for clinical speech and voice studies.     

Physiological Studies of Retrusive Movements of the Human Tongue

SUMMARY: This study identified that physiologically the superior pharyngeal constrictor muscle at the level of the base of the tongue contributes to retrusive movement of the tongue with constriction of the mid-pharyngeal cavity and possesses unique properties in terms of motor speech control along with the genioglossus muscle. From a kinematic study involving trans-nasal fiberscopy and lateral X-ray fluorography, retrusive movement of the tongue was highly correlated with constrictive movement of the mid-pharyngeal cavity. An electromyographic study revealed that the superior pharyngeal constrictor muscle at the level of the base of the tongue contributes to retrusive movement of the tongue and that the genioglossus muscle contributes to protrusive movement. We also noted that this relationship between the activities of these two muscles were in response to postural changes during vowel productions without changes in the acoustic features. These findings suggest that these two muscles act not only antagonistically to produce retrusive and protrusive movement of the tongue, but also they complement each other to conserve the shape of the vocal tract for speech production. The functional relationship between these two muscles could contribute the consecutive movement of human speech production under various conditions and might be useful when applying rehabilitation approaches for the patients with neurological speech and swallowing disorders.     

Chemical bond and density of states of silver and copper halides based on DV-Xα method

We have calculated the electronic states of AgX and CuX (X = Cl, Br, I) by using the DV-Xα method. The density of states (DOS) and the bond overlap populations (BOP) of AgX and CuX are calculated by assuming the several model clusters with the nearest, second, and third-neighbor atoms. The cluster-size variations of DOS and BOP are discussed from the viewpoint of the chemical bond between the neighboring ions. We found that the BOP of AgI and CuX are larger than those of AgCl and AgBr. This result is consistent with the Phillips ionicity for A ^N B^8-N compounds. Furthermore, we have investigated the variation of the BOP between Ag and I ions along the diffusion path of the mobile Ag ions in the model cluster for α-AgI.