Showing papers by "Tokyo University of Science published in 2000"
TL;DR: In this article, the authors showed that the performance of NiO/NaTaOO3 photocatalysts was improved by doping of lanthanides, La, Pr, Nd, Sm, Gd, Tb and Dy into NaTaO3.
287 citations
TL;DR: Small enantiomeric imbalances of chiral molecules induced by physical factors can be amplified by the present asymmetric autocatalysis.
Abstract: Asymmetric autocatalysis is a process of automultiplication of a chiral compound in which chiral product acts as a chiral catalyst for its own production. The discovery and the development of asymmetric autocatalysis of pyrimidyl-, quinolyl-, and pyridylalkanols are described in the enantioselective additions of diisopropylzinc to the corresponding nitrogen-containing aldehydes. (Alkynylpyrimidyl)alkanols automultiply with a yield of over 99% and over 99.5% ee. Asymmetric autocatalysts with extremely low ee's automultiply with significant amplification of ee's without the need for any other chiral auxiliaries. Small enantiomeric imbalances of chiral molecules induced by physical factors can be amplified by the present asymmetric autocatalysis.
274 citations
TL;DR: The functionalized PEG layer thus prepared on a biodegradable polylactide surface has both nonfouling and ligand-binding properties and may have promising utility as engineered biomaterials including tissue engineering scaffolds.
158 citations
TL;DR: It is concluded that beta-rubromycin appears to be a lead structure for the development of more potent and selective inhibitors of human telomerase.
Abstract: We found that a group of rubromycins and their analogues, a class of quinone antibiotics that possesses benzofuran and benzodipyran rings to form a spiroketal system, strongly inhibited human telomerase as assessed with a modified telomeric repeat amplification protocol. beta- and gamma-Rubromycins and purpuromycin appeared to be the most potent telomerase inhibitors, with 50% inhibitory concentrations (IC(50)) of about 3 microM, and griseorhodins A and C also showed comparable potencies for the inhibition (IC(50) = 6-12 microM). In contrast, opening of the spiroketal system of beta-rubromycin, giving rise to alpha-rubromycin, substantially decreased its inhibitory potency toward telomerase (IC(50) > 200 microM), indicating the essential role of the spiroketal system in telomerase inhibition. A kinetic study of the inhibition by beta-rubromycin revealed a competitive interaction with respect to the telomerase substrate primer, with a K(i) of 0.74 microM, whereas a mixed type inhibition was observed with respect to the nucleotide substrate. beta-Rubromycin was also potent in inhibiting retroviral reverse transcriptases but had virtually no effect on other DNA/RNA-modifying enzymes including DNA and RNA polymerases, deoxyribonuclease, and topoisomerase. Although beta-rubromycin showed nonspecific cytotoxicities, reducing proliferation of cancer cells (IC(50) approximately 20 microM), we conclude that beta-rubromycin appears to be a lead structure for the development of more potent and selective inhibitors of human telomerase.
136 citations
TL;DR: The BASH-deficient B cells scarcely proliferated or up-regulated B7-2 in response to BCR ligation and poorly proliferated upon CD40 ligation or lipopolysaccharide stimulation, which indicates that BASH is critical for preB cell receptor signaling inducing proliferation of large preB cells and the following differentiation, for peripheral B cell maturation, and for BCR signaling inducing activation/proliferation of B cells.
Abstract: B cell antigen receptor signals development, activation, proliferation, or apoptosis of B cells depending on their condition, and its proper signaling is critical for activation and homeostasis of the immune system. The B cell-restricted adaptor protein BASH (also termed BLNK/SLP-65) is rapidly phosphorylated by the tyrosine kinase Syk after BCR ligation and binds to various signaling proteins. BASH structurally resembles SLP-76, which is essential for T cell development and T cell receptor signaling. To evaluate the role for BASH in B cell development and function in vivo, we disrupted BASH alleles in embryonic stem cells by means of homologous recombination and used these cells to complement lymphocyte-incompetent blastocysts from RAG2-deficient mice. In the resultant chimeric mice, T cell development was apparently normal, but B cell development was impaired, and a normally rare population of large preB cells expressing preB cell receptor dominated in the bone marrow in place of small preB cells, although they were mostly noncycling. In addition, the mature B cell populations in the periphery and the bone marrow profoundly decreased in size, as did B-1 cells in the peritoneal cavity, and serum Ig was severely reduced. The BASH-deficient B cells scarcely proliferated or up-regulated B7-2 in response to BCR ligation and poorly proliferated upon CD40 ligation or lipopolysaccharide stimulation. This phenotype indicates that BASH is critical for preB cell receptor signaling inducing proliferation of large preB cells and the following differentiation, for peripheral B cell maturation, and for BCR signaling inducing activation/proliferation of B cells.
134 citations
TL;DR: A thin layer of hydrogel possessing a highly ordered three-dimensional architecture is prepared, and its applicability as a biofunctional material is explored and its thickness can be controlled by the number of coatings.
Abstract: A variety of surfaces have been modified with hydrophilic polymers and hydrogels for biomedical and biotechnical applications. The modification reduces nonspecific adsorption of biomolecules such as proteins and allows the immobilization of bioactive molecules without loss of activity. We prepared a thin layer of hydrogel possessing a highly ordered three-dimensional architecture as shown in Scheme 1, and explored its applicability as a biofunctional material. The hydrogels consist of laminated layers of stabilized reactive polymeric micelles from a block copolymer of poly(ethylene glycol) -poly(D,L-lactide) (PEGPLA) and polyallylamine. 1,2 The PEG-PLA bearing an acetal group at the PEG-end and a methacryloyl group at the PLA-end was prepared by anionic ring-opening polymerization of corresponding monomers as reported in our previous publication. 1 The micelle prepared by dialysis was stabilized by polymerizing the methacryloyl group in the core and made reactive by the hydrolysis of the acetal group on the surface of the micelle. 1 The resultant aldehyde-bearing micelle of 30 -35 nm in diameter was coated on the aminated surface at 22 °C in the presence of NaCNBH3. Since the micelle bears aldehyde groups on its surface, it reacts with an amine on the substrate to form a Schiff base that can be reduced into a stable secondary amine by NaCNBH3. Due to the polymerization of the PLA-end located in the core, the micellar structure was maintained, while nonpolymerized micelles disrupted when they covered the substrate. 2 A multilayer structure was then formed by the alternate coatings of polyallylamine (PAlAm) and the micelles. 3 This procedure is presented in Scheme 1. Following the formation of a single layer of the micelles on the substrate, amino groups were introduced on the top of the micellar layer by tethering PAlAm onto the surface-attached micelles for additional attachment of the second layer of the micelles. By repeating these alternate coatings of micelles and PAlAm in the presence of NaCNBH 3, micellar multilayers can be formed on the substrate. The resultant multilayer is a thin hydrogel possessing layer-by-layer structure, and the thickness of the layer can be controlled by the number of coatings, which is peculiar to this method. 3
72 citations
TL;DR: In this article, a linear block copolymer of poly(ethylene glycol) (PEG) and poly (ethylenimine) (PEI) possessing an acetal group at the PEG chain end was prepared by a heterotelechelic PEG macroinitiator technique.
Abstract: A new linear block copolymer of poly(ethylene glycol) (PEG) and poly(ethylenimine) (PEI) possessing an acetal group at the PEG chain end was prepared by a heterotelechelic PEG macroinitiator technique. Heterotelechelic PEG with an acetal group at one end and a methanesulfonic group at the other end (acetal-PEG-SO2CH3) was synthesized by the anionic ring-opening polymerization of ethylene oxide (EO) initiated with potassium 3,3-diethoxypropanolate (PDP), followed by end-capping with methanesulfonyl chloride. Acetal-PEG-SO2CH3 was then used as a macroinitiator for the cationic ring-opening polymerization of 2-methyl-2-oxazoline (Oz) to form the block copolymer, acetal-PEG-POz. The block efficiency attained almost 100%, allowing to control the molecular weight of the POz segment by the initial monomer/initiator ratio. Alkaline hydrolysis of the repeating acetyl groups in the POz segment gave the completely deacylated block copolymer retaining the acetal group at the PEG chain end. The acetal-PEG-poly(ethylen...
71 citations
TL;DR: The anisotropy in the T dependence of chi's is universal, i.e., chic approximately 1.6chiab, showing that there is only a single T-dependent component in the chi's, which implies that the Curie-like behavior observed in overdoped samples is also caused by a DOS effect.
Abstract: We find in the Bi2Sr2CaCu2O8+delta system that the characteristic temperatures T*chi [below which the uniform susceptibilities chiabT (Hperpendicularc) and chicT (Hparallelc) decrease] and T*(rhoc) [below which the out-of-plane resistivity rhoc(T) shows typical upturn] coincide for all doping levels. We attribute the T dependence of chi's and rhoc to the anomalous (pseudogapped) density of states (DOS) in high- Tc cuprates. Furthermore, the anisotropy in the T dependence of chi's is universal, i.e., chic approximately 1.6chiab, showing that there is only a single T-dependent component in the chi's. This implies that the Curie-like behavior (dchi/dT<0) observed in overdoped samples is also caused by a DOS effect.
65 citations
TL;DR: In this article, the effects of cross-wind on flame properties for unconfined fires were investigated using an O.lm XO diffusion burner employed as a model fire source.
Abstract: Experiments were conducted to characterize the effects of cross-wind on flame properties for unconfined fires. Propane gas was used as a fuel in a O.lm XO.lm diffusion burner employed as a model fire source. The effects of the floor around a fire source, which would control the volume of air entrained into the hot current, were also investigated. Empirical models of the apparent flame height of the inclined flame are presented. We also develop empirical models of the flame tilt angle based on the balance of mass fluxes given by the upward hot current and cross-wind. These models are based on functions of dimensionless heat release rate and Froude number. The values of empirical coefficients and exponents were derived from the experimental results. The calculated flame length based on the flame tilt angle and the apparent flame height was compared with experimental results, showing that models can be used to estimate flame length in cross-winds.
53 citations
TL;DR: In this article, the importance of doping or alloying with In for obtaining high external quantum efficiency was shown for GaN-based single-quantum-well (SQW) structures in terms of localization effects due to quantum-disk (Q-disk [M. Sugawara, Phys. Rev. B 51, 10743 (1995)])-size potential minima in the QW plane.
Abstract: The importance of doping or alloying with In for obtaining high external quantum efficiency was shown for GaN-based single-quantum-well (SQW) structures in terms of localization effects due to quantum-disk (Q-disk [M. Sugawara, Phys. Rev. B 51, 10743 (1995)])-size potential minima in the QW plane. The ultraviolet light-emitting diode with lightly In-alloyed InGaN SQW exhibited an electroluminescence peak from the band-tail states. Monochromatic cathodoluminescence mapping images of In0.03Ga0.97N SQW indicated the presence of Q-disk-size effective bandgap variation. Furthermore, cubic InGaN QW which does not suffer from the piezoelectric field normal to the QW plane, also exhibited a broad band-tail.
53 citations
TL;DR: A novel member of the BASH/SLP-76 immunoreceptor-coupled adaptor family expressed in mast cells, termed MIST (for mast cell Immunoreceptor signal transducer), which has later been found to be identical to a recently reported cytokine-dependent hemopoietic cell linker, Clnk, might serve as a target for anti-allergic therapy.
Abstract: Cross-linking of the high-affinity IgE receptor (FceRI) on mast cells by IgE‐antigen complex triggers signal transduction cascades leading to the release of inflammatory mediators and production of cytokines, which are critical for the development of allergic reactions We have identified a novel member of the BASH/SLP-76 immunoreceptor-coupled adaptor family expressed in mast cells, termed MIST (for mast cell immunoreceptor signal transducer), which has later been found to be identical to a recently reported cytokine-dependent hemopoietic cell linker, Clnk Upon FceRI cross-linking, MIST/Clnk is tyrosine phosphorylated and associates with signaling proteins, phospholipase Cγ, Vav, Grb2 and linker for activation of T cells (LAT) Overexpression of a mutant form of MIST/Clnk inhibited FceRI-mediated degranulation, increase in intracellular Ca 2 , NF-AT
TL;DR: The induction of endogenous glutathione immediately after low-dose gamma-ray irradiation is at least partially responsible for the enhancement of immune function, and may throw light on the mechanisms of carcinostatic effects induced by low dose ionizing radiation.
Abstract: Purpose : To examine the relation between the induction of an increased glutathione level and the elevated proliferative response of mouse splenocytes by a small dose of γ-rays. Materials and methods : Male ICR strain mice, 7 weeks of age, were divided into irradiated and non-irradiated control groups. Irradiation was done with γ-rays from a 137 Cs source at a dose of 50cGy (1.11Gy/min). Glutathione content in the splenocytes was measured using a modified spectrophotometric technique. Concanavalin A (Con A)-induced proliferative response of the splenocytes after whole-body γ-ray irradiation was estimated from the 3 H-thymidine incorporation into the cells. Results : The glutathione level in mouse splenocytes increased 2h after whole-body γ-ray irradiation at 50 cGy, peaked at 4h and thereafter decreased almost to the zero-time level by 12-h postirradiation. A significant enhancement of Con A-induced proliferation was observed in the splenocytes obtained from the wholebody-irradiated animals between 2h and...
TL;DR: K2LnTa5O15 (Ln = La, Pr, Nd, Sm, Gd, Tb, Dy, and Tm) loaded with NiO co-catalysts showed photocatalytic activities for water splitting into H2 and O2 in stoichiometric amounts under UV light irradi...
Abstract: K2LnTa5O15 (Ln = La, Pr, Nd, Sm, Gd, Tb, Dy, and Tm) loaded with NiO co-catalysts showed photocatalytic activities for water splitting into H2 and O2 in stoichiometric amounts under UV light irradi...
TL;DR: In this article, it was found that polyvinyl alcohol effectively stabilizes the dichloromethane in water emulsion, and the release of estradiol from poly (lactide-co-glycolide) microspheres containing 0.15, 0.3, 1.5 and 2.25% was observed for 30 days and 100 days, respectively.
TL;DR: Phenotypic and phylogenetic studies were performed with 10 strains of bacteriochlorophyll-containing bacteria isolated from a variety of marine environments on the east and west coasts of Australia and it was concluded that these two strains should be placed into a new genus, Roseibium gen. nov.
Abstract: Phenotypic and phylogenetic studies were performed with 10 strains of bacteriochlorophyll-containing bacteria isolated from a variety of marine environments (surface of Rhodophyta, sand and algal sand mat) on the east and west coasts of Australia. The strains were aerobic, chemoheterotrophic, Gram-negative, motile rods with peritrichous flagella. Bacteriochlorophyll a was synthesized under aerobic conditions. Catalase, nitrate reductase, oxidase and phosphatase were produced. ONPG reaction was positive. The strains have been divided into genotype group 1 (seven strains) and genotype group 2 (three strains) according to previously described DNA-DNA hybridization data. Strains OCh 254T and OCh 368T have been included in genotype groups 1 and 2, respectively. The results of 165 rRNA gene sequence comparisons revealed that strains OCh 254T and OCh 368T formed a new cluster within the alpha-2 group of the alpha subclass of the Proteobacteria. The similarity value of the 16S rRNA gene sequences between strain OCh 254T and the most closely related species, Stappia aggregata, was 95.6 %. The sequence similarity value between strains OCh 254T and OCh 368T was 97.1%. It was concluded that these two strains should be placed into a new genus, Roseibium gen. nov., as Roseibium denhamense sp. nov. and Roseibium hamelinense sp. nov. The type species of the genus is Roseibium denhamense. The type strains of Roseibium denhamense and Roseibium hamelinense are OCh 254T (= JCM 10543T) and OCh 368T (= JCM 10544T), respectively.
TL;DR: In this paper, the photoreflectance (PR) spectra of high-purity, nearly free-standing GaN substrate were compared with emission and reflectance spectra, which were analyzed based on a model exciton-polariton picture in which A, B, and C free excitons couple simultaneously to an electromagnetic wave.
Abstract: Photoreflectance (PR) spectra of high-purity, nearly free-standing GaN substrate were compared with emission and reflectance spectra, which were analyzed based on a model exciton-polariton picture in which A, B, and C free excitons couple simultaneously to an electromagnetic wave. The GaN substrate with reduced dislocation density was prepared by lateral epitaxial overgrowth technique and it exhibited predominant excitonic emissions with the decay time nearly 1 ns even at room temperature. The transition energies obtained from the PR spectrum agree with the energies of bottlenecks of the excitonic polariton branches. The result means that perturbation-induced change in the dielectric function is mainly due to polaritons. Temperature dependence of the A-exciton energy was well described using a model which assumes Einstein phonons.
TL;DR: In this article, a thin hydrogel possessing layer-by-layer structure was prepared on substrates from a stabilized reactive micelle from a poly(ethylene glycol)−poly(d,l-lactide) (PEG−PLA) bearing an acetal group at the center.
Abstract: A thin hydrogel possessing layer-by-layer structure was prepared on substrates from a stabilized reactive micelle from a poly(ethylene glycol)−poly(d,l-lactide) (PEG−PLA) bearing an acetal group at...
TL;DR: In this paper, a chiral dendrimer with three or six β-amino alcohols on hyperbranched hydrocarbon chain-ends was synthesized, which can act as chiral catalysts for the enantioselective addition of dialkylzincs to aldehydes.
TL;DR: In this paper, the glass-transition behavior from the supercooled liquid of a Pd40Cu30Ni10P20 alloy was investigated by employing a power-compensated differential scanning calorimetry under continuous cooling.
Abstract: The glass-transition behavior from the supercooled liquid of a Pd40Cu30Ni10P20 alloy was investigated by employing a power-compensated differential scanning calorimetry under continuous cooling. At cooling rates of 0.83, 1.17, and 1.67 K/s, the transition was clearly detected as an abrupt decrease in heat capacity. From the difference in heat capacity between the undercooled liquid and glass, the alloy obtained at the lower cooling rate was found to have a more relaxed structure. The thermodynamic parameters determined in the present study enable us to interpret the reason for the outstandingly high glass-forming ability of the alloy.
TL;DR: The alterations in protein expression identified in this study may imply a p53‐related brain function and further information based on this study will provide new insights into the p53 function in the central nervous system.
Abstract: p53 is a tumor suppressor protein that regulates many cellular processes including the cell cycle, DNA repair, and apoptosis. It also serves as a critical regulator of neuronal apoptosis in the central nervous system (CNS). To elucidate the role of p53 in the CNS, brain proteins of p53 knock-out mice (p53−/−) were analyzed by two-dimensional gel electrophoresis (2-DE) and compared with those from p53 wild type (p53+/+) mice. Six types of brain tissue (temporal cortex, cerebellum, hippocampus, striatum, olfactory bulb, and cervical spinal cord) and other control tissues (lung and blood) from 18-week-old non-stress-induced mice were analyzed. The morphology of brains from p53−/− mice appeared to be normal and identical to that of p53+/+ mice, although lungs showed diffuse tumors that may have been caused by p53 deficiency. Comparative 2-D gel analysis showed that, on average, 7 of 886 spots from brain tissue were p53−/− specific, whereas 12 of 1008 spots from lung tissue were p53−/− specific. N-terminal amino acid sequence was determined for p53−/− specific proteins. In all brain tissues from p53−/− mice, a newly identified mouse mitochondrial NADH-ubiquinone oxidoreductase 24 kDa subunit showed decreased expression, and apolipoprotein A1 acidic forms showed increased expression. In addition, brain-type creatine kinase B chain and tubulin β-5 N-terminal fragment were increased in the p53−/− cerebellum, and a new protein in mouse, hydroxyacylglutathione hydrolase (glyoxalase II) was decreased in the temporal cortex of p53−/− mice. The alterations in protein expression identified in this study may imply a p53-related brain function. This is the first proteomic analysis on the p53−/− mouse brain, and further information based on this study will provide new insights into the p53 function in the CNS.
Kobe University1, Kyoto University2, Women's College, Kolkata3, University of Tokyo4, Niigata University5, Okayama University6, Osaka University7, Tokyo University of Science8, Tohoku University9, Tokai University10, Seoul National University11, Chonnam National University12, Dongshin University13, Boston University14, University of California, Irvine15, Stony Brook University16, University of Washington17, University of Warsaw18
11 Oct 2000-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the authors describe the construction and performance of a scintillating fiber detector used in the near detector for the K2K (KEK to Kamioka, KEK E362) long baseline neutrino oscillation experiment.
Abstract: We describe the construction and performance of a scintillating fiber detector used in the near detector for the K2K (KEK to Kamioka, KEK E362) long baseline neutrino oscillation experiment. The detector uses 3.7 m long and 0.692 mm diameter scintillating fiber coupled to image-intensifier tubes (IIT), and a CCD camera readout system. Fiber sheet production and detector construction began in 1997, and the detector was commissioned in March 1999. Results from the first K2K runs confirm good initial performance: position resolution is estimated to be about 0.8 mm, and track finding efficiency is 98±2% for long tracks (i.e., those which intersect more than 5 fiber planes). The hit efficiency was estimated to be 92±2% using cosmic-ray muons, after noise reduction at the offline stage. The possibility of using the detector for particle identification is also discussed.
23 Jan 2000
TL;DR: In this article, a new control method with square-wave currents in the motor main windings is proposed for bearingless switched reluctance motors and the rotational torque produced by the radial force winding currents is also considered.
Abstract: Bearingless switched reluctance motors have the combined characteristics of synchronous motors and magnetic bearings. Radial force production for rotor shaft magnetic suspension is explained with differential stator windings composed of the motor main windings and radial force windings. In this paper, a new control method with square-wave currents in the motor main windings is proposed. Under every condition, from no load to full load, stable operation is realized by opportunely controlling the advanced current phase angle /spl theta//sub m/, and the current pulse width /spl theta//sub m/ with the new control method. The rotational torque produced by the radial force winding currents is also considered in the new control method. It is shown in experimental results that a proposed method is very effective for stable operation at no load.
TL;DR: In this article, the diisopropylzinc was added to 5-Carbamoyl-3-pyridine carbaldehydes to act as asymmetric autocatalysts.
Abstract: 5-Carbamoyl-3-pyridyl alkanols with low e.e. act as asymmetric autocatalysts in the consecutive asymmetric autocatalytic addition of diisopropylzinc to 5-carbamoyl-3-pyridinecarbaldehydes. The e.e. of pyridyl alkanol amplified up to 88% e.e. without the need for any other chiral auxiliary.
TL;DR: In this paper, the authors investigated the switching charge of as-grown SrBi2Ta2O9 (SBT) capacitors with polarization reversal and found that the capacitors exhibit a rapid increase in leakage current at a certain applied field after the switching.
Abstract: The increase in switching charge of as-grown SrBi2Ta2O9 (SBT) capacitors with polarization reversal was investigated. We call this phenomenon wake-up. The switching charge was increased and the rectangularity of the D-E hysteresis loops was improved with polarization reversal. The switching pulse with larger amplitude, longer width and shorter period generated a larger increase in the switching charge with polarization reversal. At the same time, the capacitors came to exhibit a rapid increase in leakage current at a certain applied field after the switching. Furthermore, the D-E hysteresis loop of the capacitors with wake-up shifted toward the positive- or negative-bias field according to the sweeping direction of the applied voltage. We have concluded that some spontaneous polarizations locked by localized space charges at the interface layer in the wake-up-exhibiting SBT capacitors were freed by the application of numerous switching pulses, and trap levels generated in the interface layer by the switching rendered the rapid increase in leakage current and the voltage shift of D-E hysteresis easy.
TL;DR: Experiments suggested that in vivo SEB-induced anergy is established and/or maintained by a selective impairment in the TCR-induced activation of the Ca/calcineurin pathway.
Abstract: Clonal anergy is one of the mechanisms that may account for self tolerance induced in T cells in the periphery. In this study we used the well-documented system of in vivo administration of a superantigen, staphylococcal enterotoxin B (SEB), to induce a state of hyporesponsiveness (anergy) in murine peripheral T cells to decipher the intracellular biochemical basis for this process. The TCR-induced Ca response of in vitro activated T cells was found to be impaired with significant defects in the phosphorylation of phospholipase C-γ1. Experiments with calcium ionophore and newly established transgenic mouse lines that express an active form of calcineurin suggested that in vivo SEB-induced anergy is established and/or maintained by a selective impairment in the TCR-induced activation of the Ca/calcineurin pathway.
TL;DR: Chiral dendrimers bearing three or six chiral β-amino alcohols on the hyperbranched hydrocarbon chain-ends act as efficient chiral ligands for the enantioselective addition of diethylzinc to N -diphenylphosphinylimines to afford enantiomerically enriched N-diphexophosphinylamines with up to 94% e.g.
Abstract: Chiral dendrimers bearing three or six chiral β-amino alcohols on the hyperbranched hydrocarbon chain-ends act as efficient chiral ligands for the enantioselective addition of diethylzinc to N -diphenylphosphinylimines to afford enantiomerically enriched N -diphenylphosphinylamines with up to 94% e.e.
TL;DR: In this paper, self-assembled monolayers of heavy chalcogenes and dialkyl heavy CHs on Au(111) were prepared by a vapor adsorption method.
Abstract: Self-assembled monolayers (SAMs) of heavy chalcogenophenes and dialkyl heavy chalcogenides on Au(111) were prepared by a vapor adsorption method. The adsorption of heavy chalcogenide analogues was confirmed by X-ray photoelectron spectroscopy. The structures of the films were observed using scanning tunneling microscopy under atmospheric conditions. The SAM of selenophene was stable and showed striped patterns with a row-to-row spacing of 16 ± 1 A. Dibutyl selenide also formed striped patterns but with longer exposure times. Tellurophene and dibutyl telluride were found to adsorb on Au(111) but did not form ordered structures. The interactions of furan and thiophene with Au(111) were not strong enough for the molecule to adsorb on Au(111) at room temperature.