High-resolution submicron patterning of self-assembled monolayers using a molecular fluorine laser at 157 nm

Using a molecular fluorine laser at 157 nm wavelength, submicron patterning of organosilane self-assembled monolayers (SAMs) is demonstrated utilizing mask-contact photolithography. An organosilane, namely, octadecyltrimethoxysilane [ODS, CH(3)(CH(2))(17)Si(OCH(3))(3)], SAM is chemisorbed onto Si substrates covered with a 2 nm thick oxide layer and subsequently patterned using the laser. The optical path of the laser beam and the photomask-sample space are evacuated and then backfilled and purged with nitrogen during laser firing. The resulting pattern is investigated using various measurement techniques. The scanning probe microscopy images show that patterns are transferred to the SAM-covered Si substrates and that 500 nm features are successfully photoprinted in this way.     

Chlorovulones,new halogenated marine prostanoids with an antitumor activity from the stolonifer clavularia viridis Quoy and Gaimard

New halogenated marine prostanoids, chlorovulone I, II and III were isolated from the stolonifer $\text{Clavularia}$$\text{viridis}$ Quoy and Gaimard. The structure elucidation and the antitumor activity of chlorovulones were described.     

Electronic structures of exohedral lanthanide-C60 clusters

We have studied the electronic structures of several gas phase exohedral lanthanide (Ln)-C(60) clusters, Ln(n)C(60) (Ln=Pr, Ho, Tb, Tm, Eu, and Yb) with n=1-4, by photoionization spectroscopy of the neutrals and photoelectron spectroscopy of their anions. Both of the spectroscopic analyses reveal that most of the Ln atoms preferably take +3 oxidation states, while Eu atoms alone assume +2 oxidation states, and that C(60) accepts up to twelve donated electrons in Ln(n)C(60). An additional photoionization examination of the oxygen atom mixing into the Ln(n)C(60) clusters demonstrated that each oxygen atom reduces two electrons from C(60). This result implies that the number of accepted electrons in C(60) can be varied by a suitable choice of the number of Ln atoms and O atoms.     

Methane Decomposition in a Barium Titanate Packed-Bed Nonthermal Plasma Reactor

The behavior of lattice oxygen species of the ferroelectric material during methane oxidation was investigated using a nonthermal plasma reactor packed with BaTiO ₃ pellets. Lattice oxygen species in BaTiO ₃ play an important role in the formation of N ₂ O and the oxidation of CH ₄ . The oxidation products such as CO and CO ₂ were formed from independent reaction pathways. Lattice oxygen species were able to preferentially oxidize the carbon species deposited on the pellet surface into CO. Also, N ₂ O and NO _x were independently formed in the N ₂–O ₂ reaction, suggesting that different oxygen species give N ₂ O and NO _x. N ₂ O was produced by the oxidation of molecular nitrogen with lattice oxygen species.     

De novo design, synthesis, and function of semiartificial myoglobin conjugated with coiled-coil two-alpha-helix peptides

The introduction of a flavin chromophore on the myoglobin (Mb) surface and an effective electron-transfer (ET) reaction through the flavin were successfully achieved by utilizing the self-assembly of heterostranded coiled-coil peptides. We have prepared a semiartificial Mb, named Mb-1alphaK, in which an amphiphilic and cationic alpha-helix peptide is conjugated at the heme propionate (Heme-1alphaK). Heme-1alphaK has a covalently bound iron-protoporphyrin IX (heme) at the N terminus of a 1alphaK peptide sequence. This sequence was designed to form a heterostranded coiled-coil in the presence of a counterpart amphiphilic and anionic 1alphaE peptide sequence in a parallel orientation. Two peptides, Fla(1)-1alphaE and Fla(31)-1alphaE, both incorporating a 10-methylisoalloxazine moiety as an artificial flavin molecule, were also prepared (Fla=2-[7-(10-methyl)isoalloxazinyl]-2-oxoethyl). Heme-1alphaK was successfully inserted into apomyoglobin to give Mb-1alphaK. Mb-1alphaK recognized the flavin-modified peptides and a two-alpha-helix structure was formed. In addition, an efficient ET from reduced nicotinamide adenine dinucleotide to the heme center through the flavin unit was observed. The ET rate was faster in the presence of Fla(1)-1alphaE than in the presence of Fla(31)-1alphaE or the equivalent molecule that has no peptide chain. These results demonstrate that the introduction of a functional chromophore on the Mb surface can be achieved by using specific peptide-peptide interactions. Moreover, the dependence of the ET rate on the position of the flavin indicated that the distance between the heme active site and the flavin chromophore was regulated by the three-dimensional structure of the designed polypeptide.     

2 alpha-(3-hydroxypropyl)- and 2 alpha-(3-hydroxypropoxy)-1 alpha,25-dihydroxyvitamin D3 accessible to vitamin D receptor mutant related to hereditary vitamin D-resistant rickets

Hereditary vitamin D-resistant rickets (HVDRR) is a genetic disorder caused by mutations in the vitamin D receptor, which lead to resistance to 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)]. We found that the A ring-modified analogues, 2alpha-(3-hydroxypropyl)- and 2alpha-(3-hydroxypropoxy)-1alpha,25(OH)(2)D(3), (O1C3 and O2C3) can bind better than the natural hormone to the mutant VDR (R274A), which similar to the HVDRR mutant, R274L, had lost the hydrogen bond to the 1alpha-hydroxyl group of 1alpha,25(OH)(2)D(3).     

Colominic acid: a novel chiral selector for capillary electrophoresis of basic drugs

Capillary zone electrophoresis was used for characterising nine samples of natural organic matter (NOM) using phosphate buffer (25 mM, pH 7) and various modifiers; methanol (50 mM), acetonitrile (10%,v/v), dimethyl sulfoxide (5%,v/v), and urea (5 M). Principal component analysis (PCA) was used to examine whether the electrophoretic profiles can be utilised as fingerprints for tracing the NOM samples to their source and/or type of location. It was found that all modifiers except methanol affect the electropherograms. Furthermore, it was found that the PCA analysis carried out on the electrophoretic profiles recorded in buffer solution modified by urea gave the best results for fingerprinting. The distribution of the fingerprints suggests a model for the humic substances in which all samples can be regarded as mixtures between two endmembers: autochtonous and allocthoneous NOM.     

Structures and stabilities of 3d-transition metal-benzene organometallic clusters

In the gas phase, we have successfully synthesized organometallic clusters, M_n(benzene)_m (M=3d transition metal atoms), by using a laser vaporization method. The measurements of mass spectra and ionization energies (E_i) have revealed that the organometallic clusters can take two types of structures; layered sandwich structures (m = n + 1) and metal clusters saturatedly covered with benzenes. For early transition metals of Sc, Ti, and V, only the multiple decker sandwich structure clusters were preferentially produced, in which benzene and metal atoms are alternately piled up. For late transition metals of Co and Ni, the metal clusters saturatedly surrounded by benzenes were also produced as well as the sandwich clusters. Furthermore, the E_is of M₁(benzene)₂ (M = Sc-Ni) were systematically measured and their electronic properties will be discussed.     

Chemical analysis for small amounts of horseradish peroxidase using “porphyrinogen” as a chromogenic reagent

The properties of porphyrinogen as a new chromogenic reagent were examined. 5,10,15,20-Tetrahydro-tetraphenylporphyrinogen (TPPN) is changed to 5,10,15,20-tetraphenylporphine (TPP) by the oxidative reaction involving six electrons, and its formation of the porphine ring significantly increased the absorbance in the Soret band.The horseradish peroxidase (HRP) accelerated the oxidative reaction as a catalyst and the increment of absorbance depended upon the increase in the concentration of HRP. The reaction proceeded in the presence of dissolved oxygen and in the neighborhood of pH 7. Based on these findings, a chemical analysis by catalytic action using HRP was developed.In the procedure for this determination, the difference in absorbance at 419 nm (ΔA₄₁₉=A_s−A_b, where A_s and A_b are the absorbances of the sample solution containing HRP and the blank solution without HRP after 30 min, respectively), was measured. The determination range of HRP, which was obtained from the ΔA₄₁₉—HRP concentration curve, was 0.05-1.0 mg/l. The relative standard deviation in the median of the calibration curve was 3.19% (seven determinations), and the detection limit (S/N=3) was 29 ng/l. Furthermore, when the proposed method was applied to the enzyme immunoassay, bisphenol A (BPA) was selectively and sensitivity determined.     

A mixed version of Menger's theorem

An(a, b)-n-fan means a union ofn internally disjoint paths. Menger's theorem states that a graphG has an(a, b)-n-fan if and only ifG isn-connected betweena andb. We show thatG contains edge-disjoint(a, b)-n-fans if and only if for anyk withk0min{n–1, |V(G)|–2} and for any subsetX ofV(G)-{a, b} with cardinalityk, G-X is (n-k)-edge-connected betweena andb.