Estimation of human exposure to natural radionuclides using in vivo skull measurements

In a preliminary study, in vivo skull measurements and in vitro urine measurements of 210Pb and nulU have been performed to find out the individual, chronic exposure to waterborne natural radionuclides of a small group of Finnish people. For their domestic water, the studied individuals use water from drilled wells containing elevated concentrations of natural uranium and its daughter nuclides ((234,235,238)U, 222Rn, (226,228)Ra, 210Po, 210Pb). Enhanced 210Pb and 235U activities were observed in several people. A positive correlation is observed between the U concentration in urine (microg d(-1)) and the number of counts (cpm) in the gamma ray energy peaks originating from the decay of 235U and 234Th respectively. Calibration of the detector set-up and the determination of background sources are in progress.     

Experimental investigation of extinction properties and thermal conductivity of metal-coated dielectric fibers in vacuum

This paper describes first experimental steps of an attempt to replace evacuated multifoils by metal-coated dielectric fibers as a new superisolation. Calculations of the Rosseland mean of spectral extinction coefficients for thin highly relective fibers show that radiation transport can be reduced to the same extent that is achievable with multifoils. Experimental results of extinction coefficients and thermal conductivity of Al-coated glass fibers are reported. Apparently, the metal coating does not increase seriously the small solid thermal conductivity of pure glass fibers. The procedure for optimizing this insulation is thus reduced to an optimization of its extinction properties.     

Movement patterns of smallmouth and largemouth bass in and around a Lake Michigan harbor: The importance of water temperature

Smallmouth bass Micropterus dolomieu and largemouth bass M. salmoides in southwestern Lake Michigan use shallow, warm harbors for spawning during spring. After the reproductive period ends in early summer, catch rates from standardized sampling of smallmouth bass in harbors decrease. Fishes are presumed to use the main lake during summer but little is known about how black basses use main-lake habitat in Lake Michigan or mechanisms driving this transition. We tracked smallmouth bass (N = 26) and largemouth bass (N = 8) using radio and acoustic telemetry during 2005–2006 near North Point Marina, IL. A temperature difference persisted between inside and outside the harbor for much of May–October where harbor temperatures were generally warmer than those outside the harbor. Smallmouth bass responded to water temperature changes, inhabiting the harbor until temperatures outside the harbor approached 18.5 °C, at which time they left the harbor. Frequent temperature fluctuations of > 3 °C occurred outside the harbor within 24-hour periods. Sudden reductions in water temperature were associated with smallmouth bass temporarily returning to the harbor until the temperature outside the harbor again approached 18.5 °C. As water cooled during fall, smallmouth bass again returned to the harbor. Largemouth bass exhibited comparatively restricted movements during this time and rarely ranged outside the harbor. Thus, home range estimates for smallmouth bass (142.6 ha) were an order of magnitude greater than those of largemouth bass (12.9 ha). Both water temperature and species played a role in determining the degree of movement outside the harbor but both black basses used the harbor as a thermal refuge.     

Terrain elevation mapping results from airborne spotlight-mode coherent cross-track SAR stereo

Coherent cross-track synthetic aperture radar (SAR) stereo is shown to produce high-resolution three-dimensional maps of the Earth surface. This mode utilizes image pairs with common synthetic apertures but different squint angles allowing automated stereo correspondence and disparity estimation using complex correlation calculations. This paper presents two Ku-band, coherent cross-track stereo collects over rolling and rugged terrain. The first collect generates a digital elevation map (DEM) with 1-m posts over rolling terrain using complex SAR imagery with spatial resolution of 0.125 m and a stereo convergence angle of 13.8/spl deg/. The second collect produces multiple DEMs with 3-m posts over rugged terrain utilizing complex SAR imagery with spatial resolutions better than 0.5 m and stereo convergence angles greater than 40/spl deg/. The resulting DEMs are compared to ground-truth DEMs and relative height root-mean-square, linear error 90-percent confidence, and maximum height error are reported.     

Die Welt ist keine Scheibe

The world is not flat: from field ion microscopy to atom probe tomography Atom probe tomography has gained considerable importance in the past couple of years due to the steadily increasing demands on the capabilities of analytical tools for nanotechnology. Presently available preparation and instrumental methods allow the application of atom probe tomography also for technically relevant specimens. This affords a unique analytical approach for a quantitative and highly sensitive characterization of the chemical content of materials; by combining these features with the three dimensional registration of the elemental distributions, atomic spatial resolution can be achieved both laterally and in‐depth. For this reason, atom probe tomography is very well suited for the determination of the composition and morphology of crystalline and amorphous materials and nanostructures, and may have an enormous impact on research and development in various areas of material sciences. The first part of this contribution on modern atom probe tomography illustrates the evolution of the technique from its beginnings in the 1950s to the presently available commercial instruments. In the course of this overview, the basic physical and instrumental concepts will briefly be outlined. The second part will concentrate on the presentation of selected, current applications; these examples will serve also to emphasize some of the limitations of atom probe tomography.     

The Sleep Heart Health Study: design, rationale, and methods

The Sleep Heart Health Study (SHHS) is a prospective cohort study designed to investigate obstructive sleep apnea (OSA) and other sleep-disordered breathing (SDB) as risk factors for the development of cardiovascular disease. The study is designed to enroll 6,600 adult participants aged 40 years and older who will undergo a home polysomnogram to assess the presence of OSA and other SDB. Participants in SHHS have been recruited from cohort studies in progress. Therefore, SHHS adds the assessment of OSA to the protocols of these studies and will use already collected data on the principal risk factors for cardiovascular disease as well as follow-up and outcome information pertaining to cardiovascular disease. Parent cohort studies and recruitment targets for these cohorts are the following: Atherosclerosis Risk in Communities Study (1,750 participants), Cardiovascular Health Study (1,350 participants), Framingham Heart Study (1,000 participants), Strong Heart Study (600 participants), New York Hypertension Cohorts (1,000 participants), and Tucson Epidemiologic Study of Airways Obstructive Diseases and the Health and Environment Study (900 participants). As part of the parent study follow-up procedures, participants will be surveyed at periodic intervals for the incidence and recurrence of cardiovascular disease events. The study provides sufficient statistical power for assessing OSA and other SDB as risk factors for major cardiovascular events, including myocardial infarction and stroke.     

Intratumoral microdistribution of [131I]MB-1 in patients with B-cell lymphoma following radioimmunotherapy

Leprechaunism is a rare autosomal recessive disorder characterized by marked intrauterine and postnatal growth retardation, severe insulin resistance, and altered glucose homeostasis. This syndrome is related to mutations in the insulin receptor (IR) gene that impair the transmission of the insulin signal by several mechanisms. There is no effective therapy and patients usually die within the first months of life. Here we report the prenatal diagnosis of leprechaunism in two unrelated families in which affected children were compound heterozygotes with two different deficient IR alleles. In family Par-1, the disease IR alleles carried a missense mutation located in exon 18 (Arg1092-->Trp) and exon 20 (Glu1179-->Lys). In family Als, a 3-basepair deletion causing the loss of Asn281 in exon 3 and a major deletion of exons 10-13 were present in the maternal and paternal mutant IR alleles, respectively. Prenatal diagnosis was made in each family by a specific approach combining denaturing gradient gel electrophoresis (DGGE) and Southern blotting. This methodology allowed us to correctly predict the genotype of the two fetuses at the IR locus.     

A re-investigation of questionable subclassifications of presynaptic alpha2-autoreceptors: rat vena cava, rat atria, human kidney and guinea-pig urethra

It has been suggested that at least the majority of mammalian presynaptic alpha2-autoreceptors belong to the genetic alpha2A/D-adrenoceptor subtype. The aim of the present study was to re-examine the alpha2-autoreceptors in tissues in which previous assignments conflicted with this alpha2A/D rule: in the rat vena cava and rat heart atria, where the autoreceptors were classified as alpha2B or similar to, but not identical with, alpha2D, and in the human kidney, where they were classified as alpha2C. Also re-examined were the autoreceptors in the guinea-pig urethra, where they were suggested to be alpha2A, in agreement with the rule, but in contrast to indications that the alpha2A/D-adrenoceptor of the guinea pig possesses alpha2D pharmacological properties. Tissue pieces were preincubated with 3H-noradrenaline and then superfused and stimulated electrically under autoinhibition-free or almost autoinhibition-free conditions. The Kd values of up to 14 antagonists (including the partial agonist oxymetazoline) against the release-inhibiting effect of the alpha2 agonist 5-bromo-6-(2-imidazolin-2-ylamino)-quinoxaline (UK 14,304) were determined. UK 14,304 reduced the evoked overflow of tritium with an EC50 between 6.3 and 13.2 nM. All antagonists (except prazosin in one case) shifted the concentration-inhibition curve of UK 14,304 to the right. Comparison of the Kd values thus obtained with Kd values at known alpha2 subtypes indicated that the autoreceptors in the rat vena cava, rat atria and the guinea-pig urethra were alpha2D and those in the human kidney alpha2A. For example, the pKd values of the antagonists in the rat vena cava, in rat atria and in the guinea-pig urethra were closely correlated with pKd values at the prototypic alpha2D radioligand binding sites in the bovine pineal gland (r = 0.96, P < 0.001; r = 0.92, P < 0.01; and r = 0.95; P < 0.001) and with the pKd values at the alpha2D-autoreceptors of guinea-pig atria (r = 0.99, P < 0.001; r = 0.95, P < 0.001; and r = 0.98, P < 0.001). The pKd values at the autoreceptors in rat vena cava, rat atria and guinea-pig urethra were not significantly or more loosely correlated with pKd values at alpha2A, alpha2B and alpha2C binding sites and alpha2A-autoreceptors. On the other hand, the pKd values of the antagonists in the human kidney were closely correlated with pKd values at the prototypic alpha2A radioligand binding sites in HT29 cells (r = 0.95; P < 0.001) and with pKd values at the alpha2A-autoreceptors of the pig brain cortex (r = 0.97; P < 0.001), but were not significantly or more loosely correlated with pKd values at alpha2B, alpha2C and alpha2D binding sites and alpha2D-autoreceptors. In contrast to previous suggestions, the autoreceptors in rat vena cava and atria are alpha2D, those in the human kidney alpha2A, and those in the guinea-pig urethra equally alpha2D. All, therefore, conform to the rule that alpha2-autoreceptors belong at least predominantly to the genetic alpha2A/D subtype of the alpha2-adrenoceptor. The apparent paradox of an alpha2A-autoreceptor in the urethra of the guinea pig, a species in which the genetic alpha2A/D-adrenoceptor otherwise has alpha2D pharmacological properties, is removed.     

Phosphatidylinositol 3-kinase-gamma activates Bruton's tyrosine kinase in concert with Src family kinases

Bruton's tyrosine kinase (Btk) is essential for normal B lymphocyte development and function. The activity of Btk is partially regulated by transphosphorylation within its kinase domain by Src family kinases at residue Tyr-551 and subsequent autophosphorylation at Tyr-223. Activation correlates with Btk association with cellular membranes. Based on specific loss of function mutations, the Btk pleckstrin homology (PH) domain plays an essential role in this activation process. The Btk PH domain can bind in vitro to several lipid end products of the phosphatidylinositol 3-kinase (PI 3-kinase) family including phosphatidylinositol 3,4,5-trisphosphate. Activation of Btk as monitored by elevation of phosphotyrosine content and a cellular transformation response was dramatically enhanced by coexpressing a weakly activated allele of Src (E378G) and the two subunits of PI 3-kinase-gamma. This activation correlates with new sites of phosphorylation on Btk identified by two-dimensional phosphopeptide mapping. Activation of Btk was dependent on the catalytic activity of all three enzymes and an intact Btk PH domain and Src transphosphorylation site. These combined data define Btk as a downstream target of PI 3-kinase-gamma and Src family kinases.     

Altered proton extrusion in cells adapted to growth at low extracellular pH

Coronary vasodilator and hemodynamic profiles of JTV-506, a newly synthesized 2,2-bis-methoxymethyl benzopyran-derivative potassium channel opener, were evaluated in conscious dogs. JTV-506 (2.5-10 microg/kg, i.v.) elicited dose-dependent increases in coronary blood flow (CBF) and heart rate (HR) but only slight changes in mean blood pressure (MBP). Other vasodilators such as levcromakalim, nicorandil, diltiazem, and nitroglycerin, when administered intravenously, elicited increases in CBF and HR and a decrease in MBP. When dosed orally JTV-506 (0.01-0.1 mg/kg), levcromakalim (0.01-0.1 mg/kg), nicorandil (1-10 mg/kg), and nifedipine (3-30 mg/kg) also elicited increases in CBF and HR and a decrease in MBP. JTV-506 caused a marked increase in CBF with slight changes in HR and MBP. In contrast to JTV-506, however, the changes caused by levcromakalim, nicorandil, and nifedipine were accompanied by a marked increase in HR and a marked decrease in MBP. These results suggest that the action of JTV-506 on hemodynamics is different from that of other vasodilators, including reference potassium channel openers, and that the profile of cardiovascular action of JTV-506 may be useful in the treatment of angina pectoris.