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Theoretical and experimental investigations have been made of the three-dimensional microchannel fabrication of photostructurable glass by use of a femtosecond (fs) laser. Generally, a microchannel fabricated inside glass by the scanning focal spot of a fs laser perpendicular to the direction of laser propagation assumes an elliptical shape with a cross section of large aspect ratio. We demonstrate that one can greatly reduce the aspect ratio merely by inserting a slit, which is oriented parallel to the laser's scanning direction, before the focusing lens. Computer simulations show that a more symmetrical pattern is obtained in the vicinity of the focal point with the help of such a slit, owing essentially to a diffraction effect.

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Photoetching of polymethyl methacrylate (PMMA) for pulsed high power UV light is demonstrated. As a high power UV light source, a KrF excimer laser was used. Etching depth obtained by deep UV light irradiation has not only energy dependence, but also power dependence. It increased abruptly by increasing the exposed power density for the same exposed energy density.These experimental results show that high power excimer lasers are the effective light source for UV photoetching of PMMA.

We show that three-dimensional micro-optical components can be embedded in a photosensitive glass by a femtosecond (fs) laser. After exposure to the tightly focused fs laser beam, latent images are written inside the sample. Modified regions are developed by a postbaking process and then preferentially etched away in a 10%-dilute solution of hydrofluoric acid. After this process, hollow internal structures are formed that act as a mirror and a beam splitter. Furthermore, we find that postannealing smoothes the surfaces of the fabricated hollow structures, resulting in great improvement of their optical properties.

Corynebacterium glutamicum GlxR is a cyclic AMP (cAMP) receptor protein-type regulator. Although over 200 GlxR-binding sites in the C. glutamicum genome are predicted in silico, studies on the physiological function of GlxR have been hindered by the severe growth defects of a glxR mutant. This study identified the GlxR regulon by chromatin immunoprecipitation in conjunction with microarray (ChIP-chip) analyses. In total, 209 regions were detected as in vivo GlxR-binding sites. In vitro binding assays and promoter-reporter assays demonstrated that GlxR directly activates expression of genes for aerobic respiration, ATP synthesis, and glycolysis and that it is required for expression of genes for cell separation and mechanosensitive channels. GlxR also directly represses a citrate uptake gene in the presence of citrate. Moreover, ChIP-chip analyses showed that GlxR was still able to interact with its target sites in a mutant with a deletion of cyaB, the sole adenylate cyclase gene in the genome, even though binding affinity was markedly decreased. Thus, GlxR is physiologically functional at the relatively low cAMP levels in the cyaB mutant, allowing the cyaB mutant to grow much better than the glxR mutant.

We report the first observation of amplification of spontaneous emission on the Lyman-a transition of hydrogenlike lithium ions by optical-field-induced ionization. Using a subpicosecond KrF laser (0.5 ps, 50 mJ) focused at 10 17 W/cm 2 , singly ionized lithium ions have been further ionized to fully stripped states, resulting in the population inversion with respect to the ground state of the hydrogenic ions. A small signal gain coefficient of 20 cm _1 was obtained.PACS numbers: 32.80. Rm, 42.55.Vc, 52.50.Jm Recent research in x-ray lasers has focused on the development of more efficient and shorter wavelength lasers which can be pumped by a compact driver. Present x-ray layers [1,2] require large scale and very expensive drivers to heat a plasma medium to a desired ionization state by collisional excitation. Recently, Burnett and co-workers [3,4], Amendt, Eder, and Wilks [5], and Eder, Amendt, and Wilks [6] have proposed a new scheme for an x-ray laser based on an optical-field-induced ionization (OFI). In this scheme, an ultrashort high-intensity laser produces a plasma consisting of fully stripped ions and cold free electrons on a time scale much shorter than the recombination time. In such a plasma, a rapid recombination cascade of the electrons could lead to a population inversion because of a sufficiently low electron temperature of the plasma. X-ray lasing by OFI, however, has not yet been demonstrated.The use of OFI for the production of an x-ray laser plasma medium introduces some favorable characteristics. First, it is possible to produce population inversions with respect to the ground state of an ion [7,8], leading to a transition to much shorter wavelength compared to relevant transitions. The transition between n=2 and 1 in H-like ions has a photon energy 5 times as large as the transition between n=3 and 2 state. Second, the use of ultrashort pulses requires a lower pump energy, compared with conventional x-ray laser schemes. The recent progress in the technology of ultrashort laser pulses would make it possible to realize table top laser drivers for OFI x-ray lasers.This Letter reports the first observation of the amplification of spontaneous emission on the Lyman-a transition (13.5 nm) in H-like Li ions, using a novel optical-fieldinduced ionization scheme. A very large small-signal gain coefficient of 20 cm ~l was obtained from the exponential growth of the 13.5 nm line intensity against the linear increase of the gain length. The anisotropy of the amplified spontaneous emission was also observed by comparing with the relative intensities along on-axis and off-axis directions.Our method described in this Letter is a unique modification of the original OFI scheme proposed previously [3][4][5][6]. In our scheme, singly ionized lithium ions which are initially prepared by a nanosecond KrF excimer laser are further ionized to a fully stripped state by a subpicosecond high-intensity KrF laser. This modified scheme provides some advantages for the production of cold electrons and for pump beam foc...

Hydrogenovibrio marinus strain MH-110, an obligately lithoautotrophic hydrogen-oxidizing bacterium, fixes CO 2 by the Calvin-Benson-Bassham cycle. Strain MH-110 possesses three different sets of genes for ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO): CbbLS-1 and CbbLS-2, which belong to form I (L 8 S 8 ), and CbbM, which belongs to form II (L x ). In this paper, we report that the genes for CbbLS-1 (cbbLS-1) and CbbM (cbbM) are both followed by the cbbQO genes and preceded by the cbbR genes encoding LysR-type regulators. In contrast, the gene for CbbLS-2 (cbbLS-2) is followed by genes encoding carboxysome shell peptides. We also characterized the three RubisCOs in vivo by examining their expression profiles in environments with different CO 2 availabilities. Immunoblot analyses revealed that when strain MH-110 was cultivated in 15% CO 2 , only the form II RubisCO, CbbM, was expressed. When strain MH-110 was cultivated in 2% CO 2 , CbbLS-1 was expressed in addition to CbbM. In the 0.15% CO 2 culture, the expression of CbbM decreased and that of CbbLS-1 disappeared, and CbbLS-2 was expressed. In the atmospheric CO 2 concentration of approximately 0.03%, all three RubisCOs were expressed. Transcriptional analyses of mRNA by reverse transcription-PCR showed that the regulation was at the transcriptional level. Electron microscopic observation of MH-110 cells revealed the formation of carboxysomes in the 0.15% CO 2 concentration. The results obtained here indicate that strain MH-110 adapts well to various CO 2 concentrations by using different types of RubisCO enzymes.Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO; EC 4.1.1.39) is a key enzyme in the Calvin-Benson-Bassham (CBB) cycle. RubisCO for the CBB cycle is typically categorized into two forms. Form I RubisCO, the most common form, consists of eight large and eight small subunits in a hexadecameric (L 8 S 8 ) structure. This form is widely distributed in CO 2 -fixing organisms, including all higher plants, algae, cyanobacteria, and many autotrophic bacteria. Form II RubisCO, on the other hand, consists of only large subunits (Lx), the number of which differs among organisms. Although this form, first found in Rhodospirillum rubrum (31,42), is more widespread among species than was originally thought, its existence is limited to autotrophic bacteria. In addition to these traditional form I and form II enzymes, two novel types, form III and form IV RubisCO, have been revealed by the complete genome sequences of some archaea and bacteria (1,12, 17,47). Even though these two forms have not been shown to be a part of the CBB cycle, form III and form IV RubisCOs are fairly well established now.RubisCO for the CBB cycle catalyzes two different reactions: CO 2 fixation, in which CO 2 interacts with enzyme-bound ribulose-1,5-bisphosphate (RuBP) to produce 2 molecules of 3-phosphoglycerate (PGA), and O 2 fixation, in which O 2 interacts with enzyme-bound RuBP to produce 1 molecule each of PGA and 2-phosphoglycolate (PG). A RubisCO enzyme's efficien...