Training native English speakers to identify Japanese vowel length contrast with sentences at varied speaking rates

Native English speakers were trained to identify Japanese vowel length in three types of training differing in sentential speaking rate: slow-only, fast-only, and slow-fast. Following Pisoni and Lively's high phonetic variability hypothesis [Pisoni, D. B., and Lively, S. E., Speech Perception and Linguistic Experience, 433-459 (1995)], higher stimulus variability by means of training with two rates was hypothesized to aid learners in adapting to speech rate variation more effectively than training with only one rate. Trained participants identified the length of the second vowel of disyllables, short or long, embedded in a sentence of the respective rate, and received immediate feedback. The three trained groups' abilities before and after training were examined with tests containing sentences of slow, normal, and fast rates, and were compared with those of a control that was not trained. A robust effect of slow-fast training, a marginal effect of slow-only training, but no significant effect of fast-only training were found in the overall test scores. Slow-fast and slow-only training showed small advantages over fast-only training on the fast-rate test scores, while effects for all three training types were found on the slow- and normal-rate test scores. The degree to which the results support the high phonetic variability hypothesis is discussed.     

Transglutaminase-mediated synthesis of a DNA-(enzyme)n probe for highly sensitive DNA detection

A new synthetic strategy for DNA-enzyme conjugates with a novel architecture was explored using a natural cross-linking catalyst, microbial transglutaminase (MTG). A glutamine-donor substrate peptide of MTG was introduced at the 5-position on the pyrimidine of deoxyuridine triphosphate to prepare a DNA strand with multiple glutamine-donor sites by polymerase chain reaction (PCR). A substrate peptide that contained an MTG-reactive lysine residue was fused to the N terminus of a thermostable alkaline phoshatase from Pyrococcus furiosus (PfuAP) by genetic engineering. By combining enzymatically the substrate moieties of MTG introduced to the DNA template and the recombinant enzyme, a DNA-(enzyme)(n) conjugate with 1:n stoichiometry was successfully obtained. The enzyme/DNA ratio of the conjugate increased as the benzyloxycarbonyl-L-glutaminylglycine (Z-QG) moiety increased in the DNA template. The potential utility of the new conjugate decorated with signaling enzymes was validated in a dot blot hybridization assay. The DNA-(enzyme)(n) probe could clearly detect 10(4) copies of the target nucleic acid with the complementary sequence under harsh hybridization conditions, thereby enabling a simple detection procedure without cumbersome bound/free processes associated with a conventional hapten-antibody reaction-based DNA-detection system.     

Systematic fragmentation patterns of archaeal intact polar lipids by high-performance liquid chromatography/electrospray ionization ion-trap mass spectrometry

Archaea are ubiquitous and abundant microorganisms on Earth that mediate key global biogeochemical cycles. The headgroup attached to the sn-1 position of the glycerol backbone and the ether-linked isoprenoid lipids are among the diagnostic traits that distinguish Archaea from Bacteria and Eukarya. Over the last 30 years, numerous archaeal lipids have been purified and described in pure cultures. Coupled high-performance liquid chromatography (HPLC) ion-trap mass spectrometry (ITMS) now enables the detection and rapid identification of intact polar lipids in relatively small and complex samples, revealing a wide range of archaeal lipids in natural environments. Although major structural groups have been identified, the lack of a systematic evaluation of MS/MS fragmentation patterns has hindered the characterization of several atypical components that are therefore considered as unknowns. Here, we examined mass spectra resulting from lipid analysis of natural microbial communities using HPLC/electrospray ionization (ESI)-ITMS(n), and depicted the systematics in MS(2) fragmentation of intact archaeal lipids. This report will be particularly useful for environmental scientists interested in a rapid and straightforward characterization of intact archaeal membrane lipids.     

Redox-responsive conformational alteration of aromatic amides bearing N-quinonyl system

Redox-induced conformational alteration of N-aryl-N-phenylamides, in which the N-aryl group consists of a hydroquinone–p-quinone system, was examined. The reduced form bearing a dihydroxyphenyl or dimethoxyphenyl group exists mainly in the E-form, whereas the oxidized form bearing a N-benzoquinone moiety takes the Z-form both in the crystal and in solution. This redox-induced conformational alteration is associated with a marked change in optical properties. This system appears to have suitable properties for use in external redox stimulus-responsive functional switching.     

Hapalocyclamide: a novel phytotoxic hexapeptide of the cyanobacterium Hapalosiphon sp.

Hapalocyclamide, a novel oxazole-, thiazole- and thiazoline-containing cyclic hexapeptide, was isolated from the terrestrial cyanobacterium Hapalosiphon sp., and which showed phytotoxic activity on lettuce seedling growth. The gross structure of hapalocyclamide was established from spectroscopic data and chemical degradation. The absolute stereochemistry was determined by Marfey’s analysis. Hapalocyclamide was established as cyclo-thiazole-l-alanine-oxazole-d-alanine-d-thiazoline-d-phenylalanine.     

Hydrogen gas-sensing properties of Pt/WO<Subscript>3</Subscript> thin film in various measurement conditions

A well-known gasochromic material is Pt particle-dispersed tungsten trioxide (Pt/WO₃). Its optical properties could make it effective as a hydrogen gas sensor. In this study, Pt nanoparticle-dispersed WO₃ thin films were prepared using the sol–gel process, and their optical and electrical properties dependent on the working environment (i.e., temperature, hydrogen gas concentration, oxygen partial pressure, etc.) were investigated. The Pt/WO₃ thin films prepared at 400 °C showed the largest change in optical transmittance and electrical conductivity when exposed to hydrogen gas compared with the films prepared at other temperatures. The optical absorbance and electrical conductivity were found to be dependent on the hydrogen and oxygen gas concentration in the atmosphere because generation and disappearance of W⁵⁺ in the thin films depend on the equilibrium reaction between injection and rejection of H⁺ into and from the thin films. In addition, the equilibrium reaction depends on the hydrogen and oxygen gas concentrations.     

Degradation of Target Oligosaccharides by Anthraquinone–Lectin Hybrids with Light Switching

Anthraquinone–lectin hybrids were effectively synthesized using water‐soluble anthraquinone derivative 11 with concanavalin A (ConA) and hygrophorus russula lectin (HRL) to give anthraquinone–ConA ( 16 ) and anthraquinone–HRL ( 17 ) hybrids, respectively. These anthraquinone–lectin hybrids effectively and selectively degraded oligosaccharides containing a mannose residue as a non‐reducing terminal sugar, which has affinity for ConA and HRL, under photo‐irradiation with long‐wavelength UV light without additives and under neutral conditions. In addition, anthraquinone–HRL ( 17 ) selectively photo‐degraded only Man(α1,6)Man, which has a high affinity for HRL, among several mannosides by recognition of both the type and glycosidic linkage profile of the sugar in an oligosaccharide.     

Blue light emission from Eu ions in sol-gel-derived Al2O3-SiO2 glasses

Blue light-emitting glasses were successfully prepared by doping Eu²⁺ ions in the system Al₂O₃-SiO₂. The Al₂O₃-SiO₂ glasses doped with Eu³⁺ ions were synthesized using a sol-gel method, followed by heating in hydrogen gas atmosphere to reduce into the Eu²⁺ ions. The obtained glasses exhibited emission spectra with peak at ∼450 nm due to 4f⁶5d→4f⁷ (⁸S_7/2) transition, the intensities of which strongly changed depending on their glass composition and heating conditions. The emission quantum efficiency of 48% was achieved by heating the glass with the ratio of Al³⁺ to Eu³⁺ at about 6 at 1000 °C in hydrogen gas atmosphere. It was found that the Al₂O₃-SiO₂ glasses were appropriate not only for homogeneously doping the Eu³⁺ ions in glass structure but also reducing to Eu²⁺ ions, resulting in enhanced blue light-emission properties.     

Synthesis of phosphorylcholine-oligoethylene glycol-alkane thiols and their suppressive effect on non-specific adsorption of proteins

A series of phosphorylcholine-oligoethylene glycol-alkane thiols were synthesized, and their suppressive effect on the non-specific adsorption of proteins was evaluated by comparison with corresponding oligoethylene glycol-alkane thiols. It was found that phosphorylcholine-oligoethylene glycol-alkane thiols had a greater suppressive effect on the non-specific adsorption of proteins.