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The COSINE-100 experiment is designed to test the DAMA experiment which claimed an observation of a dark matter signal from an annual modulation in their residual event rate. To measure the 1 %-level signal amplitude, it is crucial to control and monitor nearly all environmental quantities that might systematically mimic the signal. The environmental monitoring also helps ensure a stable operation of the experiment. Here, we describe the design and performance of the centralized environmental monitoring system for the COSINE-100 experiment., 13 pages, 11 figures

Low- and high-resolution nuclease mapping of in vivo transcripts, and in vitro transcription reactions using purified RNA polymerase, were used to analyse transcription of and around the mmr gene, which specifies resistance of Streptomyces coelicolor A3(2) to methylenomycin (Mm) and is located in the middle of a cluster of Mm-production-encoding genes. Transcription of mmr is from a single major start point (tsp) which is separated by only 81 bp from a divergent tsp. A pattern of direct and inverted repeats in the nucleotide sequence in this region may play a part in regulation of these promoters. The 3′ end of the mmr transcript overlaps by 20–30 bp the 3′ end of an RNA molecule involved in Mm production. The converging transcripts both terminate at the same large inverted repeat in the DNA. Purified RNA polymerase terminated transcription at this sequence in vitro (albeit only in one orientation).

The ultrastructure of mature human dental enamel was studied by direct electron microscopy of ultrathin sections cut with a diamond knife and of replicas made from lightly etched cut surfaces. The enamel prisms were found to resemble keyholes when cut in cross-section, with the prisms measuring about 5 μ in dia. across the heads of the keyholes and about 9 μ in height over the extreme head to tail dimensions. The prisms were found to be oriented so that the heads of the prism cross-sections were directed cuspally and the tails were directed cervically. The crystallite orientation within any single prism was characterized by being coaxial with the prism in the extreme head region of the prism, but tipped more and more away from the prism axis in moving towards the tail of the prism. This orientation of crystallites in prisms was observed regardless of the plane of sectioning used to obtain a sample for observation. There was no evidence for an “interprismatic substance” between the prisms. Three-dimensional plastic models were prepared based on an idealized representation of enamel structure and sectioned for comparison with the electron micrographs. All structures observed in the micrographs could be simulated by sectioning the models in the proper planes.

Techniques are described for the routine preparation of ultra-thin sections of mature human dental enamel suitable for direct study in the electron microscope. The proper orientation of the sample block to facilitate cutting is discussed. Photomicrographs of sections prepared by such techniques are presented.