Surface-relief gratings with high spatial frequency fabricated using direct glass imprinting process.

Surface-relief gratings with high spatial frequencies were first fabricated using a direct imprinting process with a glassy carbon mold at the softening temperature of phosphate glass. A grating with maximum height of 730 nm and 500 nm period was formed on the glass surface by the pressing at the softening temperature of glass under constant pressure of 0.4 kN/cm(2). Phase retardation of 0.1 lambda was observed between TE-polarized and TM-polarized light at 600 nm wavelength.

Antireflection microstructures fabricated upon fluorine-doped SiO(2) films.

Two-dimensional periodic structures were fabricated upon a fluorine-doped SiO(2) film in which the fluorine content changed gradually in the direction of film thickness. The films were deposited by plasma-enhanced chemical-vapor deposition. The film was periodically patterned into a 1-mum period and an ~1-mum -groove depth by inductive coupled plasma reactive-ion etching followed by chemical etching in a diluted HF solution. A surface reflectance of 0.7% was attained at 1.85-mum wavelength, a value that is one fifth as large as the 3.5% Fresnel reflection of a SiO(2) substrate with a flat surface.

Diffraction gratings of photosensitive ZrO2 gel films fabricated with the two-ultraviolet-beam interference method.

Photosensitive ZrO(2) gel films were patterned with a two-beam interference method by use of a 325-nm-wavelength He-Cd laser for the first time to our knowledge. The ZrO(2) gel films were prepared from Zr(O-n-C(4)H(9))(4) chemically modified with benzoylacetone. We fabricated uniform gratings with a 0.5-microm period on Si or SiO(2) substrates by etching the gel films in ethyl alcohol after UV irradiation. A maximum diffraction efficiency of 28% was attained with the grating fabricated on Si substrate under a Littrow mounting condition by use of a 633-nm-wavelength He-Ne laser. Blazed gratings could also be fabricated.

Isolation and characterization of bulgecins, new bacterial metabolites with bulge-inducing activity.

Bulgecins A, B and C, new bacterial metabolites which induce the formation of bulges by cooperation with beta-lactam antibiotics, were isolated from the culture broth of Pseudomonas mesoacidophila. The three components, separated by column chromatography on QAE-Sephadex A-25, are water-soluble acidic compounds containing a sulfate group in the molecule. Acid hydrolysis showed that D-glucosamine and a new proline derivative are common constituents of the three components. In addition, taurine and beta-alanine are constituents of bulgecins A and B, respectively.

Thiotropocin, a new sulfur-containing 7-membered-ring antibiotic produced by a Pseudomonas sp.

Thiotropocin, a new sulfur-containing 7-membered-ring antibiotic, was isolated from a culture broth of Pseudomonas sp. CB-104. The antibiotic occurs as orange or yellowish orange needles and has the molecular formula C8H4O3S2. It is active against Gram-positive and Gram-negative bacteria, some phytopathogens and mycoplasma.

Isosulfazecin, a new beta-lactam antibiotic, produced by an acidophilic pseudomonad. Fermentation, isolation and characterization.

A novel beta-lactam antibiotic, isosulfazecin (iSZ), was found to be produced by an acidophilic pseudomonad, Pseudomonas mesoacidophila sp. nov. iSZ was produced in parallel with bacterial growth in nutrient broth containing glycerol and sodium thiosulfate under aerated conditions. iSZ was isolated by chromatography on activated charcoal and anion-exchangers and crystallized from 70% aqueous methanol. The molecular formula was determined to be C12H20N4O9S from physiochemical data. The IR and NMR spectra suggested that iSZ has a beta-lactam ring, methoxyl and sulfonate groups. On acid hydrolysis, it gave L-alanine and D-glutamic acid. iSZ is an epimeric isomer of sulfazecin. iSZ was weakly active against Gram-positive and -negative bacteria, and was strongly active against mutants hypersensitive to beta-lactam antibiotics.

Sulfazecin, a novel beta-lactam antibiotic of bacterial origin. Isolation and chemical characterization.

Sulfazecin, a new water-soluble acidic antibiotic, which is active against Gram-negative bacteria, was isolated as crystals from the culture broth of Pseudomonas acidophila G-6302 by use of anion exchange resin and activated charcoal. The molecular formula of sulfazecin was determined to be C12H20N4O9S from physicochemical data. The IR and NMR spectra suggested that this antibiotic has a beta-lactam ring, methoxyl and sulfonate groups. On acidic hydrolysis it gave D-alanine and D-glutamic acid. These chemical and physicochemical data indicated that sulfazecin is a new beta-lactam antibiotic.

Sulfazecin and isosulfazecin, novel beta-lactam antibiotics of bacterial origin.

In the long history of screening for antibiotics, fungi and actinomycetes have been the only producers of beta-lactam antibiotics although several phytopathogenic bacteria have been reported to produce toxins with a beta-lactam structure. We report here the first evidence that novel monocyclic beta-lactam antibiotics, sulfazecin and isosulfazecin, are produced by new species of Pseudomonas.

C-19393 S2 and H2, new carbapenem antibiotics. I. Taxonomy of the producing strain, fermentation and antibacterial properties.

C-19393 S2 and H2 are new carbapenem antibiotics produced by a streptomycete. The producing strain was taxonomically studied and named Streptomyces griseus subsp. cryophilus. Cobaltous compounds were necessary for production of the antibiotics. C-19393 S2 and H2 showed a broad spectrum of antibacterial activities with C-19393 H2 being 8 approximately 120 times more active than C-19393 S2. They also exhibited beta-lactamase-inhibiting activities and acted synergistically with ampicillin and cefotiam against clinical isolates resistant to beta-lactam antibiotics.