Comprehensive isolation of meiosis-specific genes identifies novel proteins and unusual non-coding transcripts in Schizosaccharomyces pombe.

In order to isolate meiosis-specific genes in Schizosaccharomyces pombe, we have constructed a subtracted cDNA library enriched in clones whose expression is enhanced during meiosis induced by nitrogen starvation. Using northern blot analysis, we isolated 31 kinds of clones whose expression was induced in a meiosis/sporulation-specific manner. We comprehensively named them meu after meiotic expression upregulated. The transcription of 20 meu genes was found to be dependent on the mei4(+) gene, which encodes a transcription factor required for the progression of meiosis. DNA sequencing indicated that most of the meu genes encode novel proteins. Notably, five of the meu genes harbor no apparent protein coding sequences, and the transcripts form stable hairpin structures, suggesting that they may generate non-coding RNAs or antisense RNAS: The results presented here imply that RNAs are also important for the comprehensive characterization of genomic expression.

Effect of a chymotrypsin-like inhibitor, TPCK, on histamine release from cultured human mast cells.

The involvement of endogenous proteases in the secretory process from human mast cells remains to be clarified. A chymotrypsin-like protease inhibitor, N-tosyl-L-phenylalanylchloromethyl ketone (TPCK), blocked both FceRI- and A23187-mediated histamine release from cultured human mast cells at concentrations above 1 microM. At 10 microM, the concentration that completely inhibited FceRI-mediated histamine release, TPCK did not inhibit the chymase activity of the lysate or that in intact cells. The addition of TPCK to cells 30 min before challenge did not affect FceRI- or A23187-mediated Ca2+ mobilization. These findings suggest that a TPCK-sensitive molecule distinct from chymase is involved in a late stage of the process of histamine release from mast cells in man.

Glancing incidence measurements of diamond turned copper mirrors.

The absorptance characteristics of diamond turned copper mirrors are measured at angles of incidence from 0 to 87 degrees . The measurements are performed at 1.06 microm for both s and p polarization and for the diamond turned grooves on the mirror surface oriented either perpendicular or parallel to the plane of incidence. To first order, the absorptances tend to follow the theoretical curves predicted by the Fresnel equations for flat bare metal surfaces. However, at glancing incidence, the Fresnel equations tend to have difficulty accurately predicting the experimental results. When the grooves are oriented perpendicular to the plane of incidence, the measured absorptance for s-polarized light is significantly higher than that predicted by theory; whereas the absorptance is slightly lower than theory when the grooves are parallel to the plane of incidence. Possible explanations for the observed absorptance behavior are discussed.

Mode matching for a passive resonant ring laser gyroscope.

An analytical method of matching the mode of an input laser to the lowest-order mode of a passive resonant ring laser gyro is described, as are the steps in determining the location and focal length of cylindrical mode matching lenses. Results were obtained with no mode matching, with a compromise spherical lens, with horizontal mode matching only, and with the proper cylindrical mode matching lenses. Compared with no mode matching, the latter case shows that the amplitude of the lowest-order mode is increased approximately 2.5 times. In addition, the number and intensity of higher-order modes are reduced to near zero, and the relative intensity of the lowest-order mode to the higher-order mode increased from approximately 5 to approximately 60 times greater.

Adherent dielectric coating of diamond-turned mirrors.

Adherent, high-reflectivity infrared, and multilayer dielectric coatings have been applied to diamond-turned aluminum, copper, and electroless nickel substrates. Samples passed cheesecloth, Scotch tape, salt fog, and humidity tests.

Calorimeter to Measure the 10.6-microm Absorption of Metal Substrate Mirrors.

We have designed, constructed, and tested an instrument to calorimetrically measure the 10.6-microm absorption a of high reflectivity metal-substrate mirrors. Optical, electrical, and thermal design considerations will be discussed. The technique of absorption measurement, including the in situ heat capacities, the reflected laser light to an accuracy of +/-4%, and the simplified data reduction technique will be discussed. From our error analysis we conclude that our accuracy is +/-0.1alpha and has a precision of 0.0005. Comparative measurements on the same mirrors by different reflectivity and absorption devices and extensive absorption data on state-of-the-art 10.6-microm metal-substrate mirrors will be presented. The best absorption that we have measured is 0.0010 for a gold-coated multidielectric enhanced mirror.

Machining of optics: an introduction.

This paper introduces machining of optics, presenting some of the history of machining progress, critical machining variables, material and geometrical capabilities, and some new results on optical evaluation of machined surfaces. A most significant development is electroplating of materials that are otherwise not presently machinable. For example, molybdenum has been electroplated with silver or gold and then successfully diamond turned. Research and development ideas for future machining studies will be briefly discussed.

Tool feed influence on the machinability of CO(2) laser optics.

Influence of tool feed on reflectivity of diamond-machined surfaces was evaluated using materials (gold, silver, and copper) from which CO(2) laser optics are primarily produced. Fifteen specimens were machined by holding all machining parameters constant, except tool feed. Tool feed was allowed to vary by controlled amounts from one evaluation zone (or part) to another. Past experience has verified that the quality of a diamond-machined surface is not a function of the cutting velocity; therefore, this experiment was conducted on the basis that a variation in cutting velocity was not an influencing factor on the diamondturning process. Inspection results of the specimens indicated that tool feeds significantly higher than 5.1 micro/rev (200 microin./rev) produced detrimental effects on the machined surfaces. In some cases, at feeds as high as 13 microm/rev (500 microin./rev), visible scoring was evident. Those surfaces produced with tool feeds less than 5.1 microm/rev had little difference in reflectivity. Measurements indicat d that their reflectivity existed in a range from 96.7% to 99.3% at 10.6 microm.

Performance characteristics of single point diamond machined metal mirrors for infrared laser applications.

Single point diamond knives have been used to machine to microinch tolerances. This micromachining can also produce optics of high quality. Optical micromachining capabilities in terms of materials, shapes, and optical figure are discussed. Comparisons are made between micromachined mirrors and superpolished surfaces including reflectivity, absorption, scatter, roughness, autocorrelation length, and Nomarski microscopy. 10.6-microm pulsed damage data and preliminary 10.6-microm cw damage investigations are also reported. Micromachined well with superpolished samples.

Improvement of absolute accuracy for a multiple bounce reflectometer through a detailed effort to reduce systematic errors.

We have constructed a multiple-bounce reflectometer similar to the one designed by Kelsall. Systematic errors present the reflectivities measured on our multiple-bounce reflectometer have been significantly reduced for high-reflectivity mirrors. This reduction came about through careful study of all components in our system. The diffraction effects of the apertures in the reflectometer were studied with the aid of a computer program that calculated the radial intensity distribution due to the Fresnel diffraction from each aperture. The systematic errors arising from the attempt to measure a concave spherical mirror were studied and minimized. A second computer program calculated the systematic error introduced by pathlength changes as the number of bounces in the reflectometer increased. The replacement of the sample thermopile detector with a thin-film bolometer along with other equipment changes has improved the absolute accuracy to 0.001 for the measured reflectivities with a demonstrated precision of 0.0003. Previous measurements had been about 0.008 low compared to measurements on the V-W pass reflectometer at China Lake, California.