Cytochemical studies of planetary microorganisms - Explorations in exobiology Status report, 1 Apr. - 1 Oct. 1967

Molecular research instrumentation for exobiological studie

Cytochemical studies of planetary microorganisms - Explorations in exobiology Status report, Sep. 1, 1965 - Apr. 1, 1966

Cytochemical studies of planetary microorganisms by fluorometry, gas chromatography and optical resolution, mass spectrometry, computer managed instrumentation, and UV microspectrometr

Relationship of planetary quarantine to biological search strategy

Decision theory biological search strategies and planetary quarantine aspects of Mars exploratory mission

Contamination of mars

Spacecraft sterilization standards and microbial contamination of Mar

Statistical Analysis of Native Contact Formation in the Folding of Designed Model Proteins

The time evolution of the formation probability of native bonds has been studied for designed sequences which fold fast into the native conformation. From this analysis a clear hierarchy of bonds emerge a) local, fast forming highly stable native bonds built by some of the most strongly interacting amino acids of the protein, b) non-local bonds formed late in the folding process, in coincidence with the folding nucleus, and involving essentially the same strongly interacting amino acids already participating in the fast bonds, c) the rest of the native bonds whose behaviour is subordinated, to a large extent, to that of the local- and non-local native contacts

The mosaics of Mars: As seen by the Viking Lander cameras

The mosaics and derivative products produced from many individual high resolution images acquired by the Viking Lander Camera Systems are described: A morning and afternoon mosaic for both cameras at the Lander 1 Chryse Planitia site, and a morning, noon, and afternoon camera pair at Utopia Planitia, the Lander 11 site. The derived products include special geometric projections of the mosaic data sets, polar stereographic (donut), stereoscopic, and orthographic. Contour maps and vertical profiles of the topography were overlaid on the mosaics from which they were derived. Sets of stereo pairs were extracted and enlarged from stereoscopic projections of the mosaics

A Criterion That Determines Fast Folding of Proteins: A Model Study

We consider the statistical mechanics of a full set of two-dimensional protein-like heteropolymers, whose thermodynamics is characterized by the coil-to-globular ($T_\theta$) and the folding ($T_f$) transition temperatures. For our model, the typical time scale for reaching the unique native conformation is shown to scale as $\tau_f\sim F(M)\exp(\sigma/\sigma_0)$, where $\sigma=1-T_f/T_\theta$, $M$ is the number of residues, and $F(M)$ scales algebraically with $M$. We argue that $T_f$ scales linearly with the inverse of entropy of low energy non-native states, whereas $T_\theta$ is almost independent of it. As $\sigma\rightarrow 0$, non-productive intermediates decrease, and the initial rapid collapse of the protein leads to structures resembling the native state. Based solely on {\it accessible} information, $\sigma$ can be used to predict sequences that fold rapidly.Comment: 10 pages, latex, figures upon reques

Replacement of PBNA in HB and HC polymers used in SRM propellant and liner

The antioxidant phenyl-beta-naphthylamine (PBNA) was used in both HB and HC polymers. The sole (domestic) supplier of PBNA has withdrawn this product from the market, primarily because of suspected health hazards. Commercially available substitute(s) were selected and qualified for use in the two polymers

Cytochemical studies of planetary microorganisms explorations in exobiology

Experiments to identify free living organisms in soils that may be substantially simpler in genetic content, and mirroring a more primitive stage of evolution than the species with which we are familiar to date, were designed. Organic chemical studies on the composition and disposition of elementary carbon leave nothing wanting as an aboriginal substrate for the original of life and early chemical evolution. Such studies were missed when it came to the interpretation of the Viking lander data, and needed for conceptual planning of future planetary missions