High resolution mass spectrometry in molecular structure and stereochemical studies - Effect of stereochemistry on the fragmentation of epimeric derivatives of azabicycloalkanes

High resolution mass spectrometry in studies of stereochemistry effect on fragmentation of epimeric derivatives of azabicycloalkane

Wolf Trap continuation study Final report

Critical evaluation of light and X ray scatter, conductivity, and fluorescence as part of Wolf Trap extraterrestrial life detector developmen

Lunar Outgassing, Transient Phenomena and The Return to The Moon, I: Existing Data

Herein the transient lunar phenomena (TLP) report database is subjected to a discriminating statistical filter robust against sites of spurious reports, and produces a restricted sample that may be largely reliable. This subset is highly correlated geographically with the catalog of outgassing events seen by the Apollo 15, 16 and Lunar Prospector alpha-particle spectrometers for episodic Rn-222 gas release. Both this robust TLP sample and even the larger, unfiltered sample are highly correlated with the boundary between mare and highlands, as are both deep and shallow moonquakes, as well as Po-210, a long-lived product of Rn-222 decay and a further tracer of outgassing. This offers another significant correlation relating TLPs and outgassing, and may tie some of this activity to sagging mare basalt plains (perhaps mascons). Additionally, low-level but likely significant TLP activity is connected to recent, major impact craters (while moonquakes are not), which may indicate the effects of cracks caused by the impacts, or perhaps avalanches, allowing release of gas. The majority of TLP (and Rn-222) activity, however, is confined to one site that produced much of the basalt in the Procellarum Terrane, and it seems plausible that this TLP activity may be tied to residual outgassing from the formerly largest volcanic ffusion sites from the deep lunar interior. With the coming in the next few years of robotic spacecraft followed by human exploration, the study of TLPs and outgassing is both promising and imperiled. We will have an unprecedented pportunity to study lunar outgassing, but will also deal with a greater burden of anthropogenic lunar gas than ever produced. There is a pressing need to study lunar atmosphere and its sources while still pristine. [Abstract abridged.]Comment: 35 pages, 3 figures, submitted to Icarus. Other papers in series found at http://www.astro.columbia.edu/~arlin/TLP

What is a sustainable healthy diet? A discussion paper

The food system today is destroying the environment upon which future food production depends. While the food system generates enough food energy for our population of over 7 billion it does not deliver adequate and affordable nutrition for all. About half the global population is inadequately or inappropriately nourished. Without action, these problems are set to become acute. As our global population grows, urbanises and becomes wealthier, it is demanding more resource intensive, energy rich foods. What, and how much we eat directly affects what, and how much is produced. We therefore need to consume more „sustainable diets‟ – diets that have lower environmental impacts, and are healthier. But what does such a diet look like? Can health, environmental sustainability, and all the other goals we have for our food system really be reconciled, or will there be trade offs

Site-Specific and Regiospecific Installation of Methylarginine Analogues into Recombinant Histones and Insights into Effector Protein Binding

Arginine methylation has emerged as a widespread post-translational modification with influence over myriad cellular processes. However, the molecular mechanisms underlying such methylarginine-dependent phenomena remain unclear. To aid in this research, a facile method was developed to install methylarginine analogues on recombinant protein for use in biochemical, biophysical, and structural studies. Through chemical conjugation of novel α,β-unsaturated amidine precursors with proteins, methylarginine mimics can be displayed with control of methylation site, extent, and regiospecificity. Analogue installation into histones using this strategy produced modified proteins that were recognized by antibodies specific to endogenous methylarginine, and these histones retained the capacity to form mononucleosomes. Moreover, a native methylarginine-specific binding domain was shown to interact with methylarginine analogue-modified substrates. This chemical conjugation method for installing methylarginine analogues provides an efficient route to produce homogeneous modified proteins for subsequent investigations of methylarginine-dependent processes

Transformation Toughening in Ceramics

The origin of transformation toughening in ceramics is examined using two separate approaches: one based on the stress field ahead of the crack and the other on the changes in thermodynamic potential during a crack increment. Both approaches yield essentially similar predictions of trends in toughness with particle size, temperature, composition, etc. The stress intensity analysis provides fully quantitative predictions of the toughness. These indicate that the shielding of the crack by the transformation zone only develops in the presence of a transformed wake, leading to R-curve behavior

The organic geochemistry of ancient sediments, part II

Chemical analysis of sediment and oil hydrocarbon content by gas chromatography and mass spectrometry to establish inception period of bio-organic evolutio

SIRT6 stabilizes DNA-dependent Protein Kinase at chromatin for DNA double-strand break repair

The Sir2 chromatin regulatory factor links maintenance of genomic stability to life span extension in yeast. The mammalian Sir2 family member SIRT6 has been proposed to have analogous functions, because SIRT6-deficiency leads to shortened life span and an aging-like degenerative phenotype in mice, and SIRT6 knockout cells exhibit genomic instability and DNA damage hypersensitivity. However, the molecular mechanisms underlying these defects are not fully understood. Here, we show that SIRT6 forms a macromolecular complex with the DNA double-strand break (DSB) repair factor DNA-PK (DNA-dependent protein kinase) and promotes DNA DSB repair. In response to DSBs, SIRT6 associates dynamically with chromatin and is necessary for an acute decrease in global cellular acetylation levels on histone H3 Lysine 9. Moreover, SIRT6 is required for mobilization of the DNA-PK catalytic subunit (DNA-PKcs) to chromatin in response to DNA damage and stabilizes DNA-PKcs at chromatin adjacent to an induced site-specific DSB. Abrogation of these SIRT6 activities leads to impaired resolution of DSBs. Together, these findings elucidate a mechanism whereby regulation of dynamic interaction of a DNA repair factor with chromatin impacts on the efficiency of repair, and establish a link between chromatin regulation, DNA repair, and a mammalian Sir2 factor

Scientific Opinion on Dietary Reference Values for iron

Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies derived Dietary Reference Values (DRVs) for iron. These include Average Requirement (AR) and Population Reference Intake (PRI). For adults, whole-body iron losses were modelled using data from US adults. Predicted absorption values, at a serum ferritin concentration of 30 \ub5g/L, of 16 % for men and 18 % for women were used to convert physiological requirements to dietary iron intakes. In men, median whole-body iron losses are 0.95 mg/day, and the AR is 6 mg/day. The PRI, calculated as the dietary requirement at the 97.5th percentile, is 11 mg/day. For postmenopausal women, the same DRVs as for men are proposed. In premenopausal women, additional iron is lost through menstruation but, because losses are highly skewed, the Panel set a PRI of 16 mg/day to cover requirements of 95 % of the population. In infants and children, requirements were calculated factorially, taking into consideration the needs for growth, replacement of losses and percentage iron absorption from the diet (10 % up to 11 years and 16 % thereafter). PRIs were estimated using a coefficient of variation of 20 %. They are 11 mg/day in infants (7\u201311 months), 7 mg/day in children aged 1\u20136 years and 11 mg/day in children aged 7\u201311 years and boys aged 12\u201317 years. For girls aged 12\u201317 years, the PRI of 13 mg/day is the midpoint of the calculated dietary requirement of 97.5 % of girls and the PRI for premenopausal women; this approach allows for the large uncertainties in the rate and timing of pubertal growth and menarche. For pregnant and lactating women, for whom it was assumed that iron stores and enhanced absorption provide sufficient additional iron, DRVs are the same as for premenopausal women