Pleistocene, Holocene and Recent Bird Gastroliths from Interior Alaska

Describes and discusses the origin of polished and rounded grains of quartz, secondary quartz, and chert from (probably) Holocene loess of Easter Egg Hill near Livengood townsite, peat on the Nenana Road, and redeposited Wisconsin loess from the Eva Creek Mine and Ready Bullion Creek Mine at 64 51 N, 148 02 W. The association of these grains with dull, angular grains of the same materials rules out soil or solifluction abrasion in place. Gizzard-bearing birds such as ptarmigan and grouse in Alaska produce glossy polish on their gizzard stones (gastroliths) comparable to that of the Pleistocene and Holocene gastroliths; the polish and roundness of the stones in living birds are more pronounced in late winter. Because the modal size classes of ancient and Recent polished gastroliths do not coincide, some of the ancient gastroliths are believed to have been produced by birds not now living in interior Alaska.Gastrolithes d'oiseaux pléistocènes, holocènes et récents de l'Alaska intérieur. On trouve dans le loess et la tourbe de l'Alaska intérieur des grains polis et arrondis de quartz, de quartz secondaire et de chert. Le diamètre intermédiaire de ces grains se situe entre 35 et 0.07 mm, les plus abondants mesurant 0.07 mm, de 2 à 4 mm et peut-être, de 10 à 20 mm. Le poli de ces grains est le produit de l'abrasion dans des gésiers d'oiseaux. Les oiseaux à gésier qui vivent aujourd'hui dans l'Alaska intérieur produisent sur leurs gastrolithes un fini poli comparable à celui des gastrolithes des dépôts holocènes et pléistocènes. Sur les gastrolithes d'oiseaux récents, le poli et l'arrondi varient directement, atteignant un maximum pour les oiseaux vivants à la fin de l'hiver. On peut croire que certaines gastrolithes polies de l'Holocène et du Pléistocène ont été produites par des oiseaux qui ne vivent plus aujourd'hui dans l'Alaska intérieur, car les classes dimensionnelles de ces gastrolithes anciennes ne coïncident plus avec celles des gastrolithes des oiseaux d'aujourd'hui

Health assessment of gasoline and fuel oxygenate vapors: Micronucleus and sister chromatid exchange evaluations

AbstractMicronucleus and sister chromatid exchange (SCE) tests were performed for vapor condensate of baseline gasoline (BGVC), or gasoline with oxygenates, methyl tert-butyl ether (G/MTBE), ethyl tert butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), t-butyl alcohol (TBA), or ethanol (G/EtOH). Sprague Dawley rats (the same 5/sex/group for both endpoints) were exposed to 0, 2000, 10,000, or 20,000mg/m3 of each condensate, 6h/day, 5days/week over 4weeks. Positive controls (5/sex/test) were given cyclophosphamide IP, 24h prior to sacrifice at 5mg/kg (SCE test) and 40mg/kg (micronucleus test). Blood was collected from the abdominal aorta for the SCE test and femurs removed for the micronucleus test. Blood cell cultures were treated with 5μg/ml bromodeoxyuridine (BrdU) for SCE evaluation. No significant increases in micronucleated immature erythrocytes were observed for any test material. Statistically significant increases in SCE were observed in rats given BGVC alone or in female rats given G/MTBE. G/TAME induced increased SCE in both sexes at the highest dose only. Although DNA perturbation was observed for several samples, DNA damage was not expressed as increased micronuclei in bone marrow cells. Inclusion of oxygenates in gasoline did not increase the effects of gasoline alone or produce a cytogenetic hazard

Individual and joint trajectories of change in bone, lean mass and physical performance in older men.

BackgroundDeclines in bone, muscle and physical performance are associated with adverse health outcomes in older adults. However, few studies have described concurrent age-related patterns of change in these factors. The purpose of this study was to characterize change in four properties of muscle, physical performance, and bone in a prospective cohort study of older men.MethodsUsing repeated longitudinal data from up to four visits across 6.9 years from up to 4681 men (mean age at baseline 72.7 yrs. ±5.3) participating in the Osteoporotic Fractures in Men (MrOS) Study, we used group-based trajectory models (PROC TRAJ in SAS) to identify age-related patterns of change in four properties of muscle, physical performance, and bone: total hip bone mineral (BMD) density (g/m2) and appendicular lean mass/ht2 (kg/m2), by DXA; grip strength (kg), by hand dynamometry; and walking speed (m/s), by usual walking pace over 6 m. We also described joint trajectories in all pair-wise combinations of these measures. Mean posterior probabilities of placement in each trajectory (or joint membership in latent groups) were used to assess internal reliability of the model. The number of trajectories for each individual factor was limited to three, to ensure that the pair-wise determination of joint trajectories would yield a tractable number of groups as well as model fit considerations.ResultsThe patterns of change identified were generally similar for all measures, with three district groups declining over time at roughly similar rates; joint trajectories revealed similar patterns with no cross-over or convergence between groups. Mean posterior probabilities for all trajectories were similar and consistently above 0.8 indicating reasonable model fit to the data.ConclusionsOur description of trajectories of change with age in bone mineral density, grip strength, walking speed and appendicular lean mass found that groups identified by these methods appeared to have little crossover or convergence of change with age, even when considering joint trajectories of change in these factors

In vitro/in vivo assessment of novel 99mTc-bombesin conjugates in human cancer tissue [abstract]

Abstract only availableReceptor-specific, radiolabeled peptides are becoming increasingly popular as targeting vectors for the development of new diagnostic radiopharmaceuticals. The over-expression of certain receptors such as the gastrin releasing peptide receptor (GRPr) on human cancer cells makes this method of drug development a viable tool for tumor targeting in vivo. Breast, pancreatic, prostate, gastric, colon, and small-cell lung cancer have demonstrated GRPr expression. In this project, we have conjugated a diaminoproionic acid (DPR) bifunctional chelator to bombesin (BBN) peptide targeting vector by solid phase peptide synthesis. BBN is an analogue of human gastrin releasing peptide (GRP) that binds to the GRPr with high affinity and specificity. Conjugates of the general structure [DPR-(X)-BBN(7-14)NH2] (X = a series of amino acid pharmacokinetic modifiers) were purified by reverse-phase high-performance liquid chromatography and characterized by electrospray-ionization mass spectrometry. Radiolabeling investigations of with fac-[99mTc(CO)3(H2O)3]+ (Isolink®) provided for metallated conjugates of the following general structure: [99mTc(CO)3-DPR-(X)-BBN(7-14)NH2]. These new conjugates demonstrated the ability to target specific human tumors in rodent models. Subsequent radiolabeling studies of [DPR-(X)-BBN(7-14)NH2] with fac-[188Re(CO)3(H2O)3]+, the therapeutic surrogate precursor of Tc-99m, have given us the potential to treat specific human tumors via these new targeting vectors. Detailed radiolabeling protocols, in vitro cell binding studies, and in vivo biodistribution assays will be reported.Harry S. Truman Memorial VA Hospita

Periodic Variability During the X-ray Decline of 4U 1636-53

We report the onset of a large amplitude, statistically significant periodicity (~46 d) in the RXTE/ASM data of the prototype X-ray burster 4U 1636-53, the X-ray flux of which has been gradually declining over the last four years. This behaviour is remarkably similar to that observed in the neutron star LMXB KS 1731-260, which is a long-term transient. We also report on an INTEGRAL/IBIS observation of 4U 1636-53 during its decline phase, and find that the hard X-ray flux (20-100 keV) indicates an apparent anti-correlation with soft X-rays (2-12 keV). We argue that 4U 1636-53 is transiting from activity to quiescence, as occurred in KS 1731-260. We also suggest that the variability during the X-ray decline is the result of an accretion rate variability related to the X-ray irradiation of the disc.Comment: 6 pages. Accepted by MNRA

Fundamental study of adhesion of corrugated board. Project 2696-4, report one : a progress report to Fourdrinier Kraft Board Institute, Inc.

"January 15, 1969.""Institute of Paper Chemistry: Gerald R. Hoffman ... Joseph J. Becher ... John W. Swanson ... R. C. McKee.