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1

The Role of Naturally Occurring Stable Isotopes in Mass Spectrometry, Part II: The Instrumentation  

PubMed Central

In the second instalment of this tutorial, the authors explain the instrumentation for measuring naturally occurring stable isotopes, specifically the magnetic sector mass spectrometer. This type of instrument remains unrivalled in its performance for isotope ratio mass spectrometry (IRMS) and the reader is reminded of its operation and its technical advantages for isotope measurements. PMID:23772101

Bluck, Les; Volmer, Dietrich A.

2013-01-01

2

Tracking Trophic Interactions in Coldwater Reservoirs Using Naturally Occurring Stable Isotopes  

Microsoft Academic Search

We measured signatures of naturally occurring stable isotopes of carbon (13C) and nitrogen (15N) in important invertebrate and fish taxa in two coldwater reservoirs in Colorado that had different food webs. One reservoir, Lake Granby, contained a large population of an opossum shrimp, Mysis relicta, and the other, Blue Mesa Reservoir, did not. We compared temporal dynamics of isotopic signatures

Brett M. Johnson; Patrick J. Martinez; Jason D. Stockwell

2002-01-01

3

Tracking Trophic Interactions in Coldwater Reservoirs Using Naturally Occurring Stable Isotopes  

Microsoft Academic Search

We measured signatures of naturally occurring stable isotopes of carbon (C) and nitrogen (N) in important invertebrate and fish taxa in two coldwater reservoirs in Colorado that had different food webs. One reservoir, Lake Granby, contained a large population of an opossum shrimp, Mysis relicta, and the other, Blue Mesa Reservoir, did not. We compared temporal dynamics of isotopic signatures

Brett M. Johnson; Patrick J. Martinez; Jason D. Stockwell

2002-01-01

4

Existence of long-lived isomeric states in naturally-occurring neutron-deficient Th isotopes  

SciTech Connect

Four long-lived neutron-deficient Th isotopes with atomic mass numbers 211 to 218 and abundances of (1-10)x10{sup -11} relative to {sup 232}Th have been found in a study of naturally-occurring Th using inductively coupled plasma-sector field mass spectrometry. It is deduced that long-lived isomeric states exist in these isotopes. The hypothesis that they might belong to a new class of long-lived high spin super- and hyperdeformed isomeric states is discussed.

Marinov, A.; Kashiv, Y. [Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Rodushkin, I. [Analytica AB, Aurorum 10, S-977 75 Luleaa (Sweden); Halicz, L.; Segal, I. [Geological Survey of Israel, 30 Malkhei Israel St., Jerusalem 95501 (Israel); Pape, A. [IPHC-UMR7178, IN2P3-CNRS/ULP, BP 28, F-67037 Strasbourg cedex 2 (France); Gentry, R. V. [Earth Science Associates, P.O. Box 12067, Knoxville, Tennessee 37912-0067 (United States); Miller, H. W. [P. O. Box 1092, Boulder, Colorado 80306-1092 (United States); Kolb, D. [Department of Physics, University GH Kassel, D-34109 Kassel (Germany); Brandt, R. [Kernchemie, Philipps University, D-35041 Marburg (Germany)

2007-08-15

5

Macro-distribution of naturally occurring alpha-emitting isotopes of U in the human skeleton  

Microsoft Academic Search

Argonne National Laboratory (ANL) exhumed the remains of two individuals who had received Pu by intravenous injection, performed Pu analysis on these remains, and then sent portions of individual bones to our laboratory. We analyzed these bone samples to determine the macro-distribution of naturally occurring alpha-emitting isotopes of U (²³⁴U and ²³⁸U). We found that the sacrum contained the highest

Narayani P. Singh; David B. Bennett; McDonald E. Wrenn

1987-01-01

6

Clumped-isotope geochemistryThe study of naturally-occurring, multiply-substituted isotopologues  

NASA Astrophysics Data System (ADS)

Clumped isotope geochemistry is concerned with the state of ordering of rare isotopes in natural materials. That is, it examines the extent to which rare isotopes (D, 13C, 15N, 18O, etc.) bond with or near each other rather than with the sea of light isotopes in which they swim. Abundances of isotopic 'clumps' in natural materials are influenced by a wide variety of factors. In most cases, their concentrations approach (within ca. 1%, relative) the amount expected for a random distribution of isotopes. Deviations from this stochastic distribution result from: enhanced thermodynamic stability of heavy-isotope 'clumps'; slower kinetics of reactions requiring the breakage of bonds between heavy isotopes; the mass dependence of diffusive and thermo-gravitational fractionations; mixing between components that differ from one another in bulk isotopic composition; biochemical and photochemical fractionations that may reflect combinations of these simpler physical mechanisms; and, in some cases, other processes we do not yet understand. Although clumped isotope geochemistry is a young field, several seemingly promising applications have already emerged. Most importantly, it appears that proportions of 13C- 18O bonds in carbonate minerals are sensitive to their growth temperatures, independent of bulk isotopic composition. Thus, 'clumped isotope' analysis of ancient carbonates can be used as a quantitative paleothermometer that requires no assumptions about the ? 18O of waters from which carbonates grew. This approach has been used to reconstruct marine temperatures across the Phanerozoic (reaching back to the Silurian), terrestrial ground temperatures across the Cenozoic, thermal histories of aqueously altered meteorites, among other applications. Clumped isotope geochemistry is also placing new constraints on the atmospheric budget and stratospheric photochemistry of CO 2, and should be capable of placing analogous new constraints on the budgets of other atmospheric gases. Finally, this field could be extended to encompass sulfates, volatile hydrocarbons, organic moieties and other materials.

Eiler, John M.

2007-10-01

7

APPLICATION OF THE NATURALLY-OCCURRING DEUTERIUM ISOTOPE TO TRACING THE CAPILLARY FRINGE  

EPA Science Inventory

Naturally-occurring deuterium is a useful tracer of subsurface hydrologic processes. A possible application includes the identification of capillary fringes in the vadose zone. Multiple and discontinuous water tables persist in many temperate regions, under various hydrogeologi...

8

BIODEGRADATION - MONITORED NATURAL ATTENUATION (MNA) FOR OXYGENATES: HOW IT EVOLVED, WHY IT OCCURS AND STABLE ISOTOPES  

EPA Science Inventory

The organisms that degrade MtBE under anaerobic conditions are evolved to acquire energy for growth by using molecular hydrogen and carbonate ion to cleave methyl ether bonds. Methyl ether bonds are common in nature and the bond also occurs in MTBE. MTBE in contaminated ground...

9

Radiometric method for determining concentration of naturally occurring isotopes and device therefor  

SciTech Connect

The proposed method essentially consists in that a sample of a substance is placed between two scintillators in immediate contact therewith whereupon said sample is hermetically sealed. Arranged in close proximity to each scintillator is a photomultiplier tube recording ionizing ..cap alpha..- and b-radiation. A selector is utilized to select pulses corresponding to ..cap alpha..- and b-particles, and delayed coincidence circuits of a recording element separate and record b-..cap alpha.. and ..cap alpha..-..cap alpha.. cascade pairs of delayed coincidences of RaC, ThC, and AcA radionuclides. Flows are measured twice at a predetermined time interval to account for emanation build-up tendency and concentration of isotopes of radium is determined from a formula.

Yakubovich, S.L.; Gerling, V.E.; Golubnichy, V.V.; Kotsen, M.E.; Stepanov, J.N.

1984-10-09

10

Analysis of Long-Term Diet Changes in Tropical Seabirds Using Naturally Occurring Stable Isotopes  

NASA Astrophysics Data System (ADS)

A clear understanding of ecosystem response to past environmental changes will provide more accurate interpretations of current ecosystem trends. With this mindset, we investigated the effects of the 1976/77 regime shift in the Pacific Ocean on a tropical pelagic community of apex predators. Using study skins from museum collections from 1960 to 2006, we measured stable carbon (?13C) and nitrogen (?15N) isotopes for a suite of ecologically and phylogenetically diverse seabirds from the eastern Pacific warm pool. In this region, seabirds generally forage by depending on subsurface predators to drive prey to the surface or by associating with oceanographic features that increase productivity or aggregate prey in space and time. We found that annual ?15N means from Sooty Terns (Onychoprion fuscatus) feathers decreased by 2.98, while all other species did not show any significant trends over the study period. Annual ?13C means from feathers of Sooty Terns, Wedge-tailed Shearwaters (Puffinus pacificus), Red-footed Boobies (Sula sula) and Juan Fernandez Petrels (Petrodroma externa) decreased by an average of 1.02, at rates between 0.01 and 0.02 ?13C per year-1. Our results do not suggest a response of the seabird community to the 1976/77 regime shift. Instead, they are consistent with a trophic shift and/or change in foraging area for Sooty Terns and a long-term decrease in feather ?13C for the eastern Pacific warm pool seabird community. This long-term decrease in feather ?13C is most likely due to the Suess effect and less likely due to a decline in primary productivity of the system. We hypothesize that a deepening trend in thermocline depth in the eastern Pacific warm pool affected Sooty Terns more than other species in the subsurface predator-dependent guild that depend less on smaller subsurface predators like skipjack tuna.

Vilchis, I.; Ballance, L.

2010-12-01

11

Comparing naturally occurring stable isotopes of nitrogen, carbon, and strontium as markers for the rearing locations of Atlantic salmon ( Salmo salar )  

Microsoft Academic Search

We compared the success of using naturally occurring stable isotopes of N, C, and Sr as markers for the rearing locations of juvenile salmon. We analyzed the isotopic signatures (? 15 Na nd? 13C in muscle and scales and 87 Sr\\/86Sr in otoliths) of >200 juvenile Atlantic salmon (Salmo salar) from 12 tributaries of the Connecticut River, USA. Young salmon

Brian P. Kennedy; C. Page Chamberlain; Joel D. Blum; Keith H. Nislow; Carol L. Folt

2005-01-01

12

Isotopic composition and origin of indigenous natural perchlorate and co-occurring nitrate in the southwestern United States  

USGS Publications Warehouse

Perchlorate (ClO4?) has been detected widely in groundwater and soils of the southwestern United States. Much of this ClO4? appears to be natural, and it may have accumulated largely through wet and dry atmospheric deposition. This study evaluates the isotopic composition of natural ClO4? indigenous to the southwestern U.S. Stable isotope ratios were measured in ClO4? (?18O, ?17O, ?37Cl) and associated NO3? (?18O, ?17O, ?15N) in groundwater from the southern High Plains (SHP) of Texas and New Mexico and the Middle Rio Grande Basin (MRGB) in New Mexico, from unsaturated subsoil in the SHP, and from NO3?-rich surface caliche deposits near Death Valley, California. The data indicate natural ClO4? in the southwestern U.S. has a wide range of isotopic compositions that are distinct from those reported previously for natural ClO4? from the Atacama Desert of Chile as well as all known synthetic ClO4?. ClO4? in Death Valley caliche has a range of high ?17O values (+8.6 to +18.4 ), overlapping and extending the Atacama range, indicating at least partial atmospheric formation via reaction with ozone (O3). However, the Death Valley ?37Cl values (?3.1 to ?0.8 ) and ?18O values (+2.9 to +26.1) are higher than those of Atacama ClO4?. In contrast, ClO4? from western Texas and New Mexico has much lower ?17O (+0.3 to +1.3), with relatively high ?37Cl (+3.4 to +5.1 ) and ?18O (+0.5 to +4.8 ), indicating either that this material was not primarily generated with O3 as a reactant or that the ClO4? was affected by postdepositional O isotope exchange. High ?17O values in ClO4? (Atacama and Death Valley) are associated with high ?17O values in NO3?, indicating that both compounds preserve characteristics of O3-related atmospheric production in hyper-arid settings, whereas both compounds have low ?17O values in less arid settings. Although ?17O variations in terrestrial NO3? can be attributed to mixing of atmospheric (high ?17O) and biogenic (low ?17O) NO3?, variations in ?17O of terrestrial ClO4? are not readily explained in the same way. This study provides important new constraints for identifying natural sources of ClO4? in different environments by multicomponent isotopic characteristics, while presenting the possibilities of divergent ClO4? formation mechanisms and(or) ClO4? isotopic exchange in biologically active environments.

Jackson, W. Andrew; Bhlke, John Karl; Gu, Baohua; Hatzinger, Paul B.; Sturchio, Neil C.

2010-01-01

13

Naturally occurring methyl salicylate glycosides.  

PubMed

As an important part of non steroids anti-inflammation drug (NSAIDs), salicylate has developed from natural substance salicylic acid to natrium salicylicum, to aspirin. Now, methyl salicylate glycoside, a new derivative of salicylic acid, is modified with a -COOH group integrated one methyl radical into formic ether, and a -OH linked with a monosaccharide, a disaccharide or a trisaccharide unit by glycosidic linkage. It has the similar pharmacological activities, anti-inflammatory, analgesic, antipyretic and antithrombotic as the previous salicylates' without resulting in serious side effects, particularly the gastrointestinal toxicity. Owing to the superiority of those significant bioactivities, methyl salicylate glycosides have became a hot research area in NSAIDs for several years. This paper compiles all 9 naturally occurring methyl salicylate glycosides, their distribution of the resource and pharmacological mechanism, which could contribute to the new drug discovery. PMID:24329991

Mao, Ping; Liu, Zizhen; Xie, Meng; Jiang, Rui; Liu, Weirui; Wang, Xiaohong; Meng, Shen; She, Gaimei

2014-01-01

14

Naturally occurring homoisoflavonoids and their pharmacological activities.  

PubMed

Homoisoflavonoids, a special subclass of flavonoids, are rarely found in nature, mainly existing in Fabaceae and Asparagaceae families and being less common in Polygonaceae, Portulacaceae, Orchidaceae, and Gentianaceae families. Until now, approximately 240 natural occurring homoisoflavonoids have been identified from roots, barks, heartwood, bulbs, leaves, and seeds of the plants from the above mentioned families, which have often been used in traditional medicine. Homoisoflavonoids have been reported with a broad range of bioactivities, including anti-microbial, anti-mutagenic, anti-oxidant, immunomodulatory, anti-diabetic, cytotoxic, anti-angiogenic, vasorelaxant, and anti-inflammatory effects. To organize this review, the homoisoflavonoids were classified into five groups based on their structures: sappanin-type (I), scillascillin-type (II), brazilin-type (III), caesalpin-type (IV), and protosappanin-type (V). The structures of natural occurring homoisoflavonoids are described, and their proposed biosynthetic pathway and recent pharmacological studies are discussed. The main purpose of this review is to provide a comprehensive and up-to-date state of knowledge from phytochemical and pharmacological studies performed on homoisoflavonoids during the past decades. Homoisoflavonoids might have a large potential for further investigations of their bioactivities in order to identify important leads. PMID:25153098

Lin, Li-Gen; Liu, Qian-Yu; Ye, Yang

2014-08-01

15

Leaching of technologically enhanced naturally occurring radioactive materials.  

PubMed

A form of waste associated with mining activities is related to the type of deposit being mined and to the procedure of exploitation and enrichment adopted. The wastes usually contain relatively large amounts of technologically enhanced naturally occurring radioactive materials (TENORM). The TENORM are often stored on the surface. Consequently, they can be leached as a result of interaction with aqueous solutions of different chemical composition. This further leads to pollution of water and soil in the vicinity of the stored wastes. The paper presents the results of laboratory investigation aimed at quantifying the leaching process of samples originating from uranium dumps and storage reservoirs associated with brine pumped from coal mines. The leaching process was investigated with respect to selected elements: uranium isotopes, radium isotopes, iron, barium and sodium. The samples were exposed to aqueous solutions of different chemical composition. The experiments revealed that TENORM in form of sulphate compounds are the most resistant against leaching. The leaching coefficient for radium isotopes varies from a few thousandth percent to a few hundredth percent. On the other hand, for TENORM occurring in sand or sludge, the leaching coefficient for uranium and radium isotopes ranged from a few hundredth percent to a few percent. PMID:17482828

Chau, Nguyen Dinh; Chru?ciel, Edward

2007-08-01

16

Naturally occurring contamination in the Mancos Shale.  

PubMed

Some uranium mill tailings disposal cells were constructed on dark-gray shale of the Upper Cretaceous Mancos Shale. Shale of this formation contains contaminants similar to those in mill tailings. To establish the contributions derived from the Mancos, we sampled 51 locations in Colorado, New Mexico, and Utah. Many of the groundwater samples were saline with nitrate, selenium, and uranium concentrations commonly exceeding 250,?000, 1000, and 200 ?g/L, respectively. Higher concentrations were limited to groundwater associated with shale beds, but were not correlated with geographic area, stratigraphic position, or source of water. The elevated concentrations suggest that naturally occurring contamination should be considered when evaluating groundwater cleanup levels. At several locations, seep water was yellow or red, caused in part by dissolved organic carbon concentrations up to 280 mg/L. Most seeps had (234)U to (238)U activity ratios greater than 2, indicating preferential leaching of (234)U. Seeps were slightly enriched in (18)O relative to the meteoric water line, indicating limited evaporation. Conceptually, major ion chemical reactions are dominated by calcite dissolution following proton release from pyrite oxidation and subsequent exchange by calcium for sodium residing on clay mineral exchange sites. Contaminants are likely released from organic matter and mineral surfaces during weathering. PMID:22225529

Morrison, Stan J; Goodknight, Craig S; Tigar, Aaron D; Bush, Richard P; Gil, April

2012-02-01

17

Antigenotoxic activity of naturally occurring furanocoumarins.  

PubMed

This study was designed to investigate the antigenotoxic effects of a series of naturally occurring furanocoumarins (NOFs) including isoimperatorin, imperatorin, (+)-oxypeucedanin, (+)-byakangelicol, and (+)-byakangelicine on antigenotoxic activities against genotoxicity induced by carcinogens [furylfuramide and N-methyl-N'-nitro-N-nitrosoguanidine], and procarcinogens 2-[2-(acetylamino)-4-amino-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-4) and 2-amino-3,4-dimethyl-3H-imidazo-[4,5-f] quinoline (MeIQ)] to genotoxic metabolites catalyzed by rat S9 or rat and human recombinant cytochrome P450 (CYP) 1As by using the umu test based on SOS response. Five different NOFs, which were found in the human diets, strongly inhibited the umuC induction by procarcinogens, but did not be affected by carcinogens. Notably, isoimperatorin and (+)-byakangelicol were found to be potent inhibitors on the metabolic activation of PBTA-4 and MeIQ to genotoxic metabolites catalyzed by rat and human CYP1A1, or rat and human CYP1A2, respectively. In addition, to elucidate the mechanism of their antigenotoxic effects against procarcinogens, the effects of NOFs on rat and human CYP1A1- or rat and human CYP1A2-related enzyme activities of 7-ethoxyresorufin-O-deethylase (EROD) were also investigated. Reduction of the EROD activities by some of the NOFs with IC(50) values of 0.23-20.64 ?M was found to be due to strong inhibition of CYP1A1 and CYP1A2 dependent monooxygenases. Furthermore, the mechanism of inhibitions by NOFs on human CYP1A1 and CYP1A2 was analyzed by means of Dixon plots plus Cornish-Bowden plots. The kinetic studies of inhibition types revealed that these compounds inhibited the human CYP1A1 and CYP1A2 a variety of modes rather than by a uniform one. Moreover, experiments with a two-stage incubation indicated that NOFs, except for imperatorin, inhibited human CYP1A1 in a mechanism-based manner, but directly inhibited human CYP1A2. This data suggest that certain NOFs, to which humans are exposed in the diet, may be capable of affecting the metabolic activation of procarcinogens due to inhibitions of CYP1A1 and CYP1A2 enzymes. PMID:21786339

Marumoto, Shinsuke; Oda, Yoshimitsu; Miyazawa, Mitsuo

2011-10-01

18

Naturally Occurring Radioactive Materials in Cargo at US Borders  

SciTech Connect

In the U.S. and other countries, large numbers of vehicles pass through border crossings each day. The illicit movement of radioactive sources is a concern that has resulted in the installation of radiation detection and identification instruments at border crossing points. This activity is judged to be necessary because of the possibility of an act of terrorism involving a radioactive source that may include any number of dangerous radionuclides. The problem of detecting, identifying, and interdicting illicit radioactive sources is complicated by the fact that many materials present in cargo are somewhat radioactive. Some cargo contains naturally occurring radioactive material or technologically-enhanced naturally occurring radioactive material that may trigger radiation portal monitor alarms. Man-made radioactive sources, especially medical isotopes, are also frequently observed and produce alarms. Such nuisance alarms can be an operational limiting factor for screening of cargo at border crossings. Information about the nature of the radioactive materials in cargo that can interfere with the detection of radionuclides of concern is necessary. This paper provides such information for North American cargo, but the information may also be of use to border control officials in other countries. (PIET-43741-TM-361)

Kouzes, Richard T.; Ely, James H.; Evans, John C.; Hensley, Walter K.; Lepel, Elwood A.; McDonald, Joseph C.; Schweppe, John E.; Siciliano, Edward R.; Strom, Daniel J.; Woodring, Mitchell L.

2006-01-01

19

Tetrahedral boron in naturally occurring tourmaline  

SciTech Connect

Evidence for boron in both trigonal and tetrahedral coordination has been found in {sup 11}B magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectra of natural, inclusion-free specimens of aluminum-rich lithian tourmaline from granitic pregmatites.

Tagg, S.L.; Cho, H. [Pacific Northwest National Lab., Richland, WA (United States). Environmental Molecular Sciences Lab.; Dyar, M.D. [Mount Holyoke Coll., South Hadley, MA (United States). Dept. of Geology and Geography; Grew, E.S. [Univ. of Maine, Orono, ME (United States). Dept. of Geological Sciences

1999-09-01

20

Naturally occurring hepatozoonosis in coyotes from Oklahoma.  

PubMed

Nine of 16 free-ranging coyotes (Canis latrans) from central Oklahoma (USA) had naturally acquired infections of Hepatozoon americanum. Infections were confirmed by recognition of tissue stages closely resembling H. americanum in skeletal and cardiac muscle. At the time coyotes were collected they were infested with a variety of ticks, including adult Gulf Coast ticks (Amblyomma maculatum). We propose that the high prevalence of H. americanum in this small sample of free-ranging coyotes and the ability of these same animals to harbor adult populations of A. maculatum is an important component of the epizootiology of canine hepatozoonosis in North America. PMID:10073352

Kocan, A A; Breshears, M; Cummings, C; Panciera, R J; Ewing, S A; Barker, R W

1999-01-01

21

Naturally occurring hydroxytyrosol: synthesis and anticancer potential.  

PubMed

Several epidemiological and animal studies have suggested that polyphenols, a group of secondary plant metabolites occurring mainly in the plant kingdom, may have a protective effect against some chronic degenerative diseases such as cancer. Polyphenols are part of the human diet, being present in vegetal food and beverages. Among them, an olive biophenol named hydroxytyrosol [2-(3,4- dihydroxyphenyl)ethanol, HTyr] has recently received particular attention because of its antioxidant, antiproliferative, pro-apoptotic, and anti-inflammatory activities, which have the potential to specifically counteract all cancer hallmarks, thus representing the expectant biological activities underlying the anti-tumor properties of this polyphenol. After a description of the synthetic procedures to prepare pure HTyr, this review takes into consideration the chemopreventive and chemotherapeutic potential of HTyr as the result of its antioxidant, antiproliferative and anti-inflammatory activities. In particular, the review is focused on the current knowledge of the main cellular and molecular mechanisms used by HTyr to affect carcinogenesis, highlighting the specific oncogenic and inflammatory signaling pathways potentially targeted by HTyr. PMID:23244583

Bernini, R; Merendino, N; Romani, A; Velotti, F

2013-01-01

22

Analysis of natural-occurring and synthetic sexual hormones in sludge-amended soils by matrix solid-phase dispersion and isotope dilution gas chromatography-tandem mass spectrometry.  

PubMed

A sensitive analytical method is presented for the simultaneous determination of four synthetic estrogens and six steroid hormones in sludge-amended soil. The method employs matrix solid-phase dispersion (MSPD) followed by isotope dilution gas chromatography-tandem mass spectrometry injecting a large volume sample (10?L) after trimethylsilyl derivatization, using the solvent vent mode. It affords good resolution, high sensitivity and reproducibility and freedom from interferences even from complex matrices as soil amended with sewage sludge. The limits of detection (LODs) ranged from 10 to 300pgg(-1) with testosterone and progesterone having the highest limits. Soil amended with sewage sludge was spiked at 2, 10, 25 and 50ngg(-1) and the recoveries after MSPD with acetonitrile:methanol (90:10, v/v), ranged from 80 to 110% with relative standard deviations ?9%. The method was applied to the analysis of six soil samples collected from agricultural plots and forested fields that had been amended with sewage sludge using isotopically labeled surrogates. Three of the synthetic estrogens studied were found at least in one of the six samples analyzed and trans-androsterone and estrone were the only natural hormones detected, although at very low levels (?0.4ngg(-1)). PMID:23465128

Albero, Beatriz; Snchez-Brunete, Consuelo; Miguel, Esther; Prez, Rosa A; Tadeo, Jos L

2013-03-29

23

Isotope shifts of natural Sr+ measured by laser fluorescence in a  

E-print Network

Isotope shifts of natural Sr+ measured by laser fluorescence in a sympathetically cooled Coulomb, France Abstract We measured by laser spectroscopy the isotope shifts between naturally-occurring even-isotopes-component Coulomb crystal in a linear Paul trap containing 103­104 laser-cooled Sr+ ions. The isotope shifts

Paris-Sud XI, Université de

24

Stable Carbon Isotopic Signatures and Fractionations Occurring During Fungal Biosynthesis of Methyl Chloride  

NASA Astrophysics Data System (ADS)

Methyl halides are responsible for approximately 25% of the equivalent chlorine involved in stratospheric ozone depletion, yet quantitative understanding of their atmospheric budgets is still incomplete. The use of an isotopic mass balance to constrain these budgets is currently being investigated. The utility of this approach will depend not only on being able to measure the source signatures and loss kinetic isotope effects contributing to their atmospheric budgets, but also in our ability to assess the variability in these terms. Natural methyl halide sources and sinks due to microbial cycling, combined with their large and variable associated isotopic effects, should have discernable effects on the global atmospheric signature of these gases. Thus, we have begun investigating the isotopic signatures of methyl halides produced by fungi, and the fractionations occurring during their biosynthesis, using controlled laboratory cultures. Measurements of the stable carbon isotopic signatures of growth medium, biomass, respired CO2, CH3Cl, and the carbon mass balance were made over the growth cycle of Inonotus andersonii, a wood-rot fungus previously shown to emit methyl halides. Resulting CH3Cl ? 13C signatures were enriched by approximately 10\\permil as compared to those previously reported for Phellinus pomaceus, another wood-rot species1. Fractionations between substrate and biomass \\{? s-b\\}, as well as biomass and gases \\{? b-g\\}, were nearly constant during exponential and early stationary phase growth. Biomass was depleted by 1\\permil compared to the 13C malt extract medium, and CH3Cl and CO2 were depleted by up to 5\\permil compared to the biomass, implying the bulk of the final CH3Cl signature is determined during CH3Cl synthesis and not during uptake of the carbon substrate. However, the magnitude of these fractionations, and the direction of ? s-b, probably depends on the complexity of the substrate. Additionally, a survey of isotopic signatures of CH3Cl produced by several fungal species on C3 and C4 substrates was begun to quantify likely variability in the natural source signature. 1 Harper, DB., R.M. Kalin, J.T.G. Hamilton, and C. Lamb, Carbon Isotope Ratios for Chloromethane of Biological Origin: Potential Tool in Determining Biological Emissions, Environ. Sci.Technol., 35, 3616-3619, 2001.

Shaw, S. L.; Henn, M. R.; Chapela, I. H.; Conrad, M. E.; Goldstein, A. H.

2003-12-01

25

Naturally occurring asbestosA recurring public policy challenge  

Microsoft Academic Search

The potential environmental hazards and associated public health issues related to exposure to respirable dusts from the vicinity of natural in-place asbestos deposits (commonly referred to as naturally occurring asbestos, NOA) have gained the regulatory and media spotlight in many areas around the United States, such as Libby, MT, Fairfax County, VA, and El Dorado Hills, CA, among others. NOA

R. J. Lee; B. R. Strohmeier; K. L. Bunker; D. R. Van Orden

2008-01-01

26

Appendix II. Calculation of Slope Factors for Naturally Occurring Radionuclides  

E-print Network

) with the principal or parent nuclide in the environment. . . . . Note that there may be circumstances, such as long-life of 5.75 y, and Th-228, with a half-life of 1.91 y. Since the naturally-occurring thorium at the uranium mines will be in equilibrium with this progeny, the thorium slope factors are calculated as the sum

27

Naturally occurring tumours in the basal metazoan Hydra.  

PubMed

The molecular nature of tumours is well studied in vertebrates, although their evolutionary origin remains unknown. In particular, there is no evidence for naturally occurring tumours in pre-bilaterian animals, such as sponges and cnidarians. This is somewhat surprising given that recent computational studies have predicted that most metazoans might be prone to develop tumours. Here we provide first evidence for naturally occurring tumours in two species of Hydra. Histological, cellular and molecular data reveal that these tumours are transplantable and might originate by differentiation arrest of female gametes. Growth of tumour cells is independent from the cellular environment. Tumour-bearing polyps have significantly reduced fitness. In addition, Hydra tumours show a greatly altered transcriptome that mimics expression shifts in vertebrate cancers. Therefore, this study shows that spontaneous tumours have deep evolutionary roots and that early branching animals may be informative in revealing the fundamental mechanisms of tumorigenesis. PMID:24957317

Domazet-Loo, Tomislav; Klimovich, Alexander; Anokhin, Boris; Anton-Erxleben, Friederike; Hamm, Mailin J; Lange, Christina; Bosch, Thomas C G

2014-01-01

28

The characteristics of gas hydrates occurring in natural environment  

NASA Astrophysics Data System (ADS)

In the past few years, extensive analyses have been carried out for characterizing the natural gas hydrate samples from Cascadia, offshore Vancouver Island; Mallik, Mackenzie Delta; Mount Elbert, Alaska North Slope; Nankai Trough, offshore Japan; Japan Sea and offshore India. With the results obtained, it is possible to give a general picture of the characteristics of gas hydrates occurring in natural environment. Gas hydrate can occur in sediments of various types, from sands to clay, although it is preferentially enriched in sediments of certain types, for example coarse sands and fine volcanic ash. Most of the gas hydrates in sediments are invisible, occurring in the pores of the sediments, while some hydrates are visible, appearing as massive, nodular, planar, vein-like forms and occurring around the seafloor, in the fractures related to fault systems, or any other large spaces available in sediments. Although methane is the main component of most of the natural gas hydrates, C2 to C7 hydrocarbons have been recognized in hydrates, sometimes even in significant amounts. Shallow marine gas hydrates have been found generally to contain minor amounts of hydrogen sulfide. Gas hydrate samples with complex gas compositions have been found to have heterogeneous distributions in composition, which might reflect changes in the composition of the available gas in the surrounding environment. Depending on the gas compositions, the structure type of a natural gas hydrate can be structure I, II or H. For structure I methane hydrate, the large cages are almost fully occupied by methane molecules, while the small cages are only partly occupied. Methane hydrates occurring in different environments have been identified with almost the same crystallographic parameters.

Lu, H.; Moudrakovski, I.; Udachin, K.; Enright, G.; Ratcliffe, C.; Ripmeester, J.

2009-12-01

29

Naturally occurring crystalline phases: analogues for radioactive waste forms  

SciTech Connect

Naturally occurring mineral analogues to crystalline phases that are constituents of crystalline radioactive waste forms provide a basis for comparison by which the long-term stability of these phases may be estimated. The crystal structures and the crystal chemistry of the following natural analogues are presented: baddeleyite, hematite, nepheline; pollucite, scheelite;sodalite, spinel, apatite, monazite, uraninite, hollandite-priderite, perovskite, and zirconolite. For each phase in geochemistry, occurrence, alteration and radiation effects are described. A selected bibliography for each phase is included.

Haaker, R.F.; Ewing, R.C.

1981-01-01

30

Naturally Occurring Animal Models with Outer Retina Phenotypes  

PubMed Central

Naturally occurring and laboratory generated animal models serve as powerful tools with which to investigate the etiology of human retinal degenerations, especially retinitis pigmentosa (RP), Leber congenital amaurosis (LCA), cone dystrophies (CD) and macular degeneration (MD). Much progress has been made in elucidating gene defects underlying disease, in understanding mechanisms leading to disease, and in designing molecules for translational research and gene-based therapy to interfere with the progression of disease. Key to this progress has been study of naturally occurring murine and canine retinal degeneration mutants. This article will review the history, phenotypes and gene defects of select animal models with outer retina (photoreceptor and retinal pigment epithelium) degeneration phenotypes. PMID:19375447

Baehr, Wolfgang; Frederick, Jeanne M.

2009-01-01

31

Borehole compensated density logs corrected for naturally occurring gamma rays  

SciTech Connect

A method for measuring formation density is disclosed. It provides a corrected gamma gamma-type density log having a correction for the adverse effects of gamma radiation from thorium, uranium and potassium ore bodies. The adjacent formation is irradiated with gamma radiation preferably from a cesium (Cs/sup 137/) source which emits gamma radiation at 0.663 Mev. Two differently longitudinally spaced detectors are used, a short spaced detector and a long spaced detector. A gamma ray spectrum observed at one of the detectors is broken down into four energy windows across the spectrum and count rate signals are determined and corrected to separate the naturally occurring gamma radiation from the scattered gamma radiation. This information may then be combined with count rate information from the other detector, thereby yielding a compensated density log corrected from naturally occurring gamma rays.

Arnold, D. M.

1985-07-16

32

Tribology of naturally occurring boric acid films on boron carbide  

Microsoft Academic Search

In this paper, we describe the formation and self-lubricating mechanisms of naturally occurring boric acid films on boron carbide (B4C) substrates. The sliding friction coefficients of yttria\\/partially stabilized zirconia pins against plain B4C substrates are quite high at 0.30.4, but are 610 times lower against the B4C substrates subjected to annealing at 800C. We determined that this low friction was

A. Erdemir; C. Bindal; C. Zuiker; E. Savrun

1996-01-01

33

Boron isotope variations in nature: a synthesis  

Microsoft Academic Search

The large relative mass difference between the two stable isotopes of boron, 10B and 11B, and the high geochemical reactivity of boron lead to significant isotope fractionation by natural processes. Published 11B values (relative to the NBS SRM-951 standard) span a wide range of 90. The lowest 11B values around 30 are reported for non-marine evaporite minerals and certain

S. Barth

1993-01-01

34

Issues related to regulatory control of naturally occurring radioactive materials  

SciTech Connect

Nearly 80% of human radiation exposure is from naturally occurring radioactive materials (NORM). While exposure from man-made sources of radiation has been well regulated, no consistent regulatory controls exist for NORM. Because elevated radiation levels have resulted from NORM enhancement activities such as occur in the petroleum, fertilizer, mining, and processing industries, some form of regulatory control is in order. In the US, regulation of NORM by federal agencies such as the Nuclear Regulatory Commission or the Environmental Protection Agency is not anticipated in the near future because there are no authorizing federal statutes. Important issues for addressing the control of NORM include source characterization and generation, radiation protection concerns, waste management and disposition, and the regulatory framework.

Chen, S.Y.

1997-04-01

35

Temporal sequencing of brain activations during naturally occurring thermoregulatory events.  

PubMed

Thermoregulatory events are associated with activity in the constituents of the spinothalamic tract. Whereas studies have assessed activity within constituents of this pathway, in vivo functional magnetic resonance imaging (fMRI) studies have not determined if neuronal activity in the constituents of the tract is temporally ordered. Ordered activity would be expected in naturally occurring thermal events, such as menopausal hot flashes (HFs), which occur in physiological sequence. The origins of HFs may lie in brainstem structures where neuronal activity may occur earlier than in interoceptive centers, such as the insula and the prefrontal cortex. To study such time ordering, we conducted blood oxygen level-dependent-based fMRI in a group of postmenopausal women to measure neuronal activity in the brainstem, insula, and prefrontal cortex around the onset of an HF (detected using synchronously acquired skin conductance responses). Rise in brainstem activity occurred before the detectable onset of an HF. Activity in the insular and prefrontal trailed that in the brainstem, appearing following the onset of the HF. Additional activations associated with HF's were observed in the anterior cingulate cortex and the basal ganglia. Pre-HF brainstem responses may reflect the functional origins of internal thermoregulatory events. By comparison insular, prefrontal and striatal activity may be associated with the phenomenological correlates of HFs. PMID:23787950

Diwadkar, Vaibhav A; Murphy, Eric R; Freedman, Robert R

2014-11-01

36

The sensitizing capacity of chimaphilin, a naturally-occurring quinone.  

PubMed

Chimaphilin is a yellow naphthoquinone which occurs naturally in various chimaphila and Pyrola species. In Chimaphila umbellata (winter green) and C. maculata, it is a major constituent. Folk medicine recommends the leaves of Chimaphila species as a topical application to treat skin diseases. Since 1887, winter green is claimed to have caused dermatitis and to have been responsible for "idiosyncrasy". Experimental sensitization using the open epicutaneous as well as Freund's complete adjuvant technique has now revealed that chimaphilin is a moderate contact sensitizer. PMID:3191678

Hausen, B M; Schiedermair, I

1988-09-01

37

Thermal resistance of naturally occurring airborne bacterial spores.  

PubMed Central

Simulation of a heat process used in the terminal dry-heat decontamination of the Viking spacecraft is reported. Naturally occurring airborne bacterial spores were collected on Teflon ribbons in selected spacecraft assembly areas and subsequently subjected to dry heat. Thermal inactivation experiments were conducted at 105, 111.7, 120, 125, 130, and 135 degrees C with a moisture level of 1.2 mg of water per liter. Heat survivors were recovered at temperatures of 135 degrees C when a 30-h heating cycle was employed. Survivors were recovered from all cycles studied and randomly selected for identification. The naturally occurring spore population was reduced an average of 2.2 to 4.4 log cycles from 105 to 135 degrees C. Heating cycles of 5 and 15 h at temperature were compared with the standard 30-h cycle at 111.7, 120, and 125 degrees C. No significant differences in inactivation (alpha = 0.05) were observed between 111.7 and 120 degrees C. The 30-h cycle differs from the 5-and 15-h cycles at 125 degrees C. Thus, the heating cycle can be reduced if a small fraction (about 10-3 to 10-4) of very resistant spores can be tolerated. PMID:727780

Puleo, J R; Bergstrom, S L; Peeler, J T; Oxborrow, G S

1978-01-01

38

Interaction between manufactured gold nanoparticles and naturally occurring organic macromolecules.  

PubMed

The increasing exploitation of nanomaterials into many consumer and other products is raising concerns as these nanomaterials are likely to be released into the environment. Due to our lack of knowledge about the environmental chemistry, transport and ecotoxicology of nanomaterials, it is of paramount importance to study how natural aquatic colloids can interact with manufactured gold nanoparticles as these interactions will determine their environmental fate and behaviour. In this context, our work aims to quantify the effect of naturally occurring riverine macromolecules--International Humic Substances Society (IHSS) Suwannee River Humic Acid Standard (SRHA)--on citrate- and acrylate-stabilized gold nanoparticles. The influence of SRHA on the stability of the gold colloids was studied as a function of pH by UV-visible absorption spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). At high ionic strengths (0.1 M), extensive and rapid aggregation occurred, while more subtle effects were observed at lower ionic strength values. Evidence was found that SRHA enhances particle stability at extreme pH values (ionic strength<0.01 M) by substituting and/or over-coating the original stabilizer on the gold nanoparticle surface, thus affecting surface charge and chemistry. These findings have important implications for the fate and behaviour of nanoparticles in the environment and their ecotoxicity. PMID:18534664

Diegoli, Sara; Manciulea, Adriana L; Begum, Shakiela; Jones, Ian P; Lead, Jamie R; Preece, Jon A

2008-08-25

39

Using Administrative Data to Identify Naturally Occurring Networks of Physicians  

PubMed Central

Background Physicians naturally form networks. Networks could form a rational basis for Accountable Care Organizations (ACOs) for defined populations of Medicare beneficiaries. Objectives To use methods from network science to identify naturally occurring networks of physicians that might be best suited to becoming ACOs. Research Design, Subjects, and Measures Using nationally representative claims data from the Medicare program for CY 2006 on 51 hospital referral regions (HRRs), we used a network-science based community-detection algorithm to identify groups of physicians likely to have pre-established relationships. We examined the proportion of care delivered within communities and compared our results to potential ACOs organized around single hospitals. Results We studied 4,586,044 Medicare beneficiaries from 51 HRRs who were seen by 68,288 active physicians practicing in those HRRs. The median community-based network ACO had 150 physicians with 5,928 ties whereas the median hospital-based network ACO had 96 physicians with 3,276 ties. Seventy-seven percent of physician visits occurred with physicians in the community-based networks as compared with 56% with physicians in the hospital-based networks; however, just 8% of specialist visits were to specialists within the hospital-based networks as compared with 60% of specialist visits within the community-based networks. Some markets seemed better suited to developing ACOs based on network communities than others. Conclusions We present a novel approach to identifying groups of physicians that might readily function as ACOs. Organic networks identified and defined in this natural and systematic manner already have physicians who exhibit close working relationships, and who, importantly, keep the vast majority of care within the networks. PMID:23807593

Landon, Bruce E.; Onnela, Jukka-Pekka; Keating, Nancy L.; Barnett, Michael L.; Paul, Sudeshna; O'Malley, A. James; Keegan, Thomas; Christakis, Nicholas A.

2013-01-01

40

Explanation for naturally occurring supernumerary limbs in amphibians.  

PubMed

The occasional occurrence of high frequencies of limb abnormalities, including extra limbs, in natural populations of amphibians has long been a puzzle. In this paper we report the discovery of a population in which such limb abnormalities appear to be caused by a parasitic flatworm (trematode) that uses amphibians as intermediate hosts. The cercarial larval stage of the trematode attacks amphibians, penetrating the skin to form cysts (metacercariae). The cysts are preferentially localized in the cloacal region, including the developing hind limb regions in larvae of both frogs (Hyla regilla) and salamanders (Ambystoma macrodactylum). A wide range of limb abnormalities are seen, including duplicated limb structures ranging from extra digits to several extra whole limbs. We hypothesize that these limb abnormalities result from localized regulatory responses of developing and regenerating limb tissues to mechanical disruption caused by the trematode cysts. We have tested this idea by implanting inert resin beads into developing limb buds of frogs and salamanders. Since this treatment can cause supernumerary limb structures, our hypothesis is sufficient to explain the naturally occurring extra limbs. PMID:2348164

Sessions, S K; Ruth, S B

1990-04-01

41

Scrap metal management issues associated with naturally occurring radioactive material  

SciTech Connect

Certain industrial processes sometimes generate waste by-products that contain naturally occurring radioactive material (NORM) at elevated concentrations. Some industries, including the water treatment, geothermal energy, and petroleum industries, generate scrap metal that may be contaminated with NORM wastes. Of these three industries, the petroleum industry probably generates the largest quantity of NORM-contaminated equipment, conservatively estimated at 170,000 tons per year. Equipment may become contaminated when NORM-containing scale or sludge accumulates inside water-handling equipment. The primary radionuclides of concern in these NORM wastes are radium-226 and radium-228. NORM-contaminated equipment generated by the petroleum industry currently is managed several ways. Some equipment is routinely decontaminated for reuse; other equipment becomes scrap metal and may be disposed of by burial at a licensed landfill, encapsulation inside the wellbore of an abandoned well, or shipment overseas for smelting. In view of the increased regulatory activities addressing NORM, the economic burden of managing NORM-contaminated wastes, including radioactive scrap metal, is likely to continue to grow. Efforts to develop a cost-effective strategy for managing radioactive scrap metal should focus on identifying the least expensive disposition options that provide adequate protection of human health and the environment. Specifically, efforts should focus on better characterizing the quantity of radioactive scrap available for recycle or reuse, the radioactivity concentration levels, and the potential risks associated with different disposal options.

Smith, K.P.; Blunt, D.L.

1995-08-01

42

Naturally occurring regulatory T cells: markers, mechanisms, and manipulation.  

PubMed

Naturally occurring CD4(+)CD25(high) forkhead box protein 3 (FOXP3)(+) regulatory T cells (nTregs) are key mediators of immunity, which orchestrate and maintain tolerance to self and foreign antigens. In the recent 1.5 decades, a multitude of studies have aimed to define the phenotype and function of nTregs and to assess their therapeutic potential for modulating immune mediated disorders such as autoimmunity, allergy, and episodes of transplant rejection. In this review, we summarize the current knowledge on the biology of nTregs. We address the exact definition of nTregs by specific markers and combinations thereof, which is a prerequisite for the state-of-the-art isolation of defined nTreg populations. Furthermore, we discuss the mechanism by which nTregs mediate immunosuppression and how this knowledge might translate into novel therapeutic modalities. With first clinical studies of nTreg-based therapies being finished, questions concerning the reliable sources of nTregs are becoming more and more eminent. Consequently, approaches allowing conversion of CD4(+) T cells into nTregs by coculture with antigen-presenting cells, cytokines, and/or pharmacological agents are discussed. In addition, genetic engineering approaches for the generation of antigen-specific nTregs are described. PMID:22362896

Schmetterer, Klaus G; Neunkirchner, Alina; Pickl, Winfried F

2012-06-01

43

Natural occurring epialleles determine vitamin E accumulation in tomato fruits.  

PubMed

Vitamin E (VTE) content is a low heritability nutritional trait for which the genetic determinants are poorly understood. Here, we focus on a previously detected major tomato VTE quantitative trait loci (QTL; mQTL(9-2-6)) and identify the causal gene as one encoding a 2-methyl-6-phytylquinol methyltransferase (namely VTE3(1)) that catalyses one of the final steps in the biosynthesis of ?- and ?-tocopherols, which are the main forms of VTE. By reverse genetic approaches, expression analyses, siRNA profiling and DNA methylation assays, we demonstrate that mQTL(9-2-6) is an expression QTL associated with differential methylation of a SINE retrotransposon located in the promoter region of VTE3(1). Promoter DNA methylation can be spontaneously reverted leading to different epialleles affecting VTE3(1) expression and VTE content in fruits. These findings indicate therefore that naturally occurring epialleles are responsible for regulation of a nutritionally important metabolic QTL and provide direct evidence of a role for epigenetics in the determination of agronomic traits. PMID:24967512

Quadrana, Leandro; Almeida, Juliana; Ass, Ramon; Duffy, Toms; Dominguez, Pia Guadalupe; Bermdez, Luisa; Conti, Gabriela; Corra da Silva, Junia V; Peralta, Iris E; Colot, Vincent; Asurmendi, Sebastian; Fernie, Alisdair R; Rossi, Magdalena; Carrari, Fernando

2014-01-01

44

Ginsenosides Are Novel Naturally-Occurring Aryl Hydrocarbon Receptor Ligands  

PubMed Central

The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor that mediates many of the biological and toxicological actions of structurally diverse chemicals. In this study, we examined the ability of a series of ginsenosides extracted from ginseng, a traditional Chinese medicine, to bind to and activate/inhibit the AHR and AHR signal transduction. Utilizing a combination of ligand and DNA binding assays, molecular docking and reporter gene analysis, we demonstrated the ability of selected ginsenosides to directly bind to and activate the guinea pig cytosolic AHR, and to stimulate/inhibit AHR-dependent luciferase gene expression in a recombinant guinea pig cell line. Comparative studies revealed significant species differences in the ability of ginsenosides to stimulate AHR-dependent gene expression in guinea pig, rat, mouse and human cell lines. Not only did selected ginsenosides preferentially activate the AHR from one species and not others, mouse cell line was also significantly less responsive to these chemicals than rat and guinea pig cell lines, but the endogenous gene CYP1A1 could still be inducted in mouse cell line. Overall, the ability of these compounds to stimulate AHR signal transduction demonstrated that these ginsenosides are a new class of naturally occurring AHR agonists. PMID:23776647

Hu, Qin; He, Guochun; Zhao, Jing; Soshilov, Anatoly; Denison, Michael S.; Zhang, Aiqian; Yin, Huijun; Fraccalvieri, Domenico; Bonati, Laura; Xie, Qunhui; Zhao, Bin

2013-01-01

45

Naturally occurring and forced azimuthal modes in a turbulent jet  

NASA Technical Reports Server (NTRS)

Naturally occurring instability modes in an axisymmetric jet were studied using the modal frequency technique. The evolution of the modal spectrum was obtained for a jet with a Reynolds number based on a diameter of 400,000 for both laminar and turbulent nozzle boundary layers. In the early evolution of the jet the axisymmetric mode was predominant, with the azimuthal modes growing rapidly but dominating only the end of the potential core. The growth of the azimuthal was observed closer to the nozzle exit for the jet in the laminar boundary layer case than for the turbulent. Target modes for efficient excitation of the jet were determined and two cases of excitation were studied. First, a jet was excited simultaneously by two helical modes, m equals plus 1 and m equals minus 1 at a Strouhal number based on jet diameter of 0.15 and the axisymmetric mode, m equals 0 at a jet diameter of 0.6. Second, m equals plus one and m equals minus 1 at jet diameter equals 0.3 and m equals 0 at jet diameter equals 0.6 were excited simultaneously. The downstream evolution of the hydrodynamic modes and the spreading rate of the jet were documented for each case. Higher jet spreading rates, accompanied by distorted jet cross sections were observed for the cases where combinations of axisymmetric and helical forcings were applied.

Raman, Ganesh; Rice, Edward J.; Reshotko, Eli

1991-01-01

46

Naturally occurring mutants inform SHBG structure and function.  

PubMed

SHBG transports and regulates the activities of androgens and estrogens. Several single nucleotide polymorphisms in the human SHBG gene have been linked to sex steroid-dependent diseases, including those associated with the metabolic syndrome. The N-terminal laminin G-like domain of SHBG includes binding sites for calcium, sex steroids, and fibulin family members, as well as a dimerization domain. We have found that 8 of 18 uncharacterized nonsynonymous single nucleotide polymorphisms within this domain alter the production or biochemical properties of SHBG in ways not previously recognized. O-Linked glycosylation at Thr7 is disrupted in SHBG T7N, whereas abnormal glycosylation of SHBG G195E limits its secretion. Three SHBG mutants (R135C, L165M, and E176K) bind estradiol with abnormally high affinity. SHBG R135C also has an increased interaction with fibulin-2. Two different substitutions within the dimer interface at R123 (R123H and R123C) reduce the affinity for 5?-dihydrotestosterone, while increasing the relative binding affinity for estradiol. SHBG T48I is defective in calcium binding, which leads to a defect in dimerization, reduced affinity for sex steroids, and an enhanced interaction with fibulin-2, which can all be restored by calcium supplementation. These naturally occurring mutants provide insight into SHBG structure and function, and defects in SHBG production or function need to be considered in the context of its utility as a biomarker of diseases. PMID:24892637

Wu, Tsung-Sheng; Hammond, Geoffrey L

2014-07-01

47

Naturally occurring radiation sources: existing or planned exposure situation?  

PubMed

After more than fifteen years of application, ICRP Publication 60 has been revised. The revision was based upon the concept of 'controllable dose' as the dose or sum of doses to an individual from a particular source that can reasonably be controlled by whatever means. The new recommendations have been published as ICRP Publication 103. The European Basic Safety Standards as well as the International Basic Safety Standards are currently under revision as a result of the new recommendations from ICRP. According to the ICRP, there have been indications that some changes to the structure and terminology of the system of protection were desirable in order to improve clarity and utility. In particular the distinction between practices and interventions may not have been clearly understood and the ICRP now recognises three types of exposure situations, which replace the previous categorisation into practices and interventions. These exposure situations are intended to cover the entire range of exposure situations: (1) planned exposure, (2) existing exposure and (3) emergency exposure. There are situations of exposure to naturally occurring radiation sources in different occupations, e.g. exposure to radon and radon progeny in workplaces other than where the exposure is required by or is directly related to the work and aircrew exposed to cosmic radiation. In the European (Euratom) and the International Basic Safety Standards, these exposure situations are treated conceptually different-either as a planned exposure situation or as an existing exposure situation. This note reviews the change of exposure situations from Publication 60 to Publication 103 and the implications for the revision of both the International and the European Basic Safety Standards. The paper draws some conclusions on the classification of the exposure situations in the two basic safety standards based on a logical interpretation of the ICRP recommendations. It is recommended that the European and the International Basic Safety Standards should be harmonised to avoid confusion among users of the standards. PMID:21149941

Hedemann-Jensen, Per

2010-12-01

48

Committed effective dose from naturally occuring radionuclides in shellfish  

NASA Astrophysics Data System (ADS)

Recognizing their importance in the average Malaysian daily diet, the radioactivity concentrations in mollusc- and crustacean-based food have been determined for key naturally occuring radionuclides. Fresh samples collected from various maritime locations around peninsular Malaysia have been processed using standard procedures; the radionuclide concentrations being determined using an HPGe ?-ray spectrometer. For molluscs, assuming secular equilibrium, the range of activities of 238U (226Ra), 232Th (228Ra) and 40K were found to be 3.280.35 to 5.340.52, 1.200.21 to 2.440.21 and 1186 to 28114 Bq kg-1 dry weight, respectively. The respective values for crustaceans were 3.020.57 to 4.700.52, 1.380.21 to 2.400.35 and 21611 to 31615 Bq kg-1. The estimated average daily intake of radioactivity from consumption of molluscs are 0.37 Bq kg-1 for 238U (226Ra), 0.16 Bq kg-1 for 232Th (228Ra) and 18 Bq kg-1 for 40K; the respective daily intake values from crustaceans are 0.36 Bq kg-1, 0.16 Bq kg-1 and 23 Bq kg-1. Associated annual committed effective doses from molluscs are estimated to be in the range 21.3 to 34.7 ?Sv for 226Ra, 19.3 to 39.1 ?Sv for 228Ra and 17.0 to 40.4 ?Sv for 40K. For crustaceans, the respective dose ranges are 19.6 to 30.5 ?Sv, 22.0 to 38.4 ?Sv and 31.1 to 45.5 ?Sv, being some several times world average values.

Khandaker, Mayeen Uddin; Wahib, Norfadira Binti; Amin, Yusoff Mohd.; Bradley, D. A.

2013-07-01

49

METHAMPHETAMINE-INDUCED NEUROTOXICITY DISRUPTS NATURALLY OCCURRING PHASIC DOPAMINE SIGNALING  

PubMed Central

Methamphetamine (METH) is a highly addictive drug that is also neurotoxic to central dopamine (DA) systems. Although striatal DA depletions induced by METH are associated with behavioral and cognitive impairments, the link between these phenomena remains poorly understood. Previous work in both METH-pretreated animals and the 6-hydroxydopamine model of Parkinsons disease suggests that a disruption of phasic DA signaling, which is important for learning and goal-directed behavior, may be such a link. However, prior studies used electrical stimulation to elicit phasic-like DA responses and were also performed under anesthesia, which alters DA neuron activity and presynaptic function. Here we investigated the consequences of METH-induced DA terminal loss on both electrically evoked phasic-like DA signals and so-called spontaneous phasic DA transients measured by voltammetry in awake rats. Not ostensibly attributable to discrete stimuli, these sub-second DA changes may play a role in enhancing reward-cue associations. METH-pretreatment reduced tissue DA content in the dorsomedial striatum and nucleus accumbens by ~55%. Analysis of phasic-like DA responses elicited by reinforcing stimulation revealed that METH pretreatment decreased their amplitude and underlying mechanisms for release and uptake to a similar degree as DA content in both striatal subregions. Most importantly, characteristics of DA transients were altered by METH-induced DA terminal loss, with amplitude and frequency decreased and duration increased. These results demonstrate for the first time that denervation of DA neurons alters naturally occurring DA transients and are consistent with diminished phasic DA signaling as a plausible mechanism linking METH-induced striatal DA depletions and cognitive deficits. PMID:23574406

Howard, Christopher D.; Daberkow, David P.; Ramsson, Eric S.; Keefe, Kristen A.; Garris, Paul A.

2013-01-01

50

Probabilities of Natural Events Occurring at Savannah River Plant  

SciTech Connect

This report documents the comprehensive evaluation of probability models of natural events which are applicable to Savannah River Plant. The probability curves selected for these natural events are recommended to be used by all SRP/SRL safety analysts. This will ensure a consistency in analysis methodology for postulated SAR incidents involving natural phenomena.

Huang, J.C.

2001-07-17

51

Organic Food Production and Its Influence on Naturally Occurring Toxins  

Microsoft Academic Search

The levels of natural plant toxins and mycotoxins in foods may be influenced by the methods used (organic vs. conventional)\\u000a for agricultural production. Research findings suggest that organic foods may possess higher levels of natural plant toxins\\u000a than conventional foods based upon mechanistic similarities between natural plant toxin production and the production of plant\\u000a secondary metabolites of nutritional interest. Specific

Carl K. Winter

52

Naturally occurring thallium: a hidden geoenvironmental health hazard?  

Microsoft Academic Search

This paper illustrates a real environmental concern and draws attention to the fact that natural processes can mobilize thallium (Tl), a highly toxic metal, which may enter the food chain as a hidden health killer with severe health impacts on local human population. Natural processes may be exacerbated by human activities such as mining and farming, and may cause enrichment

Tangfu Xiao; Jayanta Guha; Dan Boyle; Cong-Qiang Liu; Baoshan Zheng; Graham C Wilson; Alain Rouleau; Jingan Chen

2004-01-01

53

Natural mercury isotope variation in coal deposits and organic soils  

SciTech Connect

There is a need to distinguish among sources of Hg to the atmosphere in order to more fully understand global Hg pollution. In this study we investigate whether coal deposits within the United States, China, and Russia-Kazakhstan, which are three of the five greatest coal-producing regions, have diagnostic Hg isotopic fingerprints that can be used to discriminate among Hg sources. We also investigate the Hg isotopic composition of modern organic soil horizons developed in areas distant from point sources of Hg in North America. Mercury stored in coal deposits displays a wide range of both mass dependent fractionation and mass independent fractionation. {delta}{sup 202}Hg varies in coals by 3{per_thousand} and {Delta}{sup 201}Hg varies by 0.9{per_thousand}. Combining these two Hg isotope signals results in what may be a unique isotopic 'fingerprint' for many coal deposits. Mass independent fractionation of mercury has been demonstrated to occur during photochemical reactions of mercury. This suggests that Hg found in most coal deposits was subjected to photochemical reduction near the Earth's surface prior to deposition. The similarity in MDF and MIF of modern organic soils and coals from North America suggests that Hg deposition from coal may have imprinted an isotopic signature on soils. This research offers a new tool for characterizing mercury inputs from natural and anthropogenic sources to the atmosphere and provides new insights into the geochemistry of mercury in coal and soils. 35 refs., 2 figs., 1 tab.

Abir, Biswas; Joel D. Blum; Bridget A. Bergquist; Gerald J. Keeler; Zhouqing Xie [University of Michigan, Ann Arbor, MI (United States). Department of Geological Sciences

2008-11-15

54

Stable isotopes as one of nature's ecological recorders  

E-print Network

of the natural variation in stable isotopes of components of ecological systems have provided new insights ecological activi- ties. Among the many examples, carbon isotope ratios (d13 C) of plant organic matterStable isotopes as one of nature's ecological recorders Jason B. West1 , Gabriel J. Bowen2 , Thure

Ehleringer, Jim

55

Biosynthesis of toxic naturally-occurring seafood contaminants.  

PubMed

Outbreaks of human illness caused by the consumption of contaminated seafood, continues to be a major problem particularly for the shellfish industry. Toxins from marine, brackish and freshwater environments, which are often produced as a result of harmful algal blooms, have been implicated as the causative agents of these poisonings. Commonly, poisoning events have been grouped into one of six classes, Paralytic Shellfish Poisoning (PSP), Diarrhetic Shellfish Poisoning (DSP), Neurotoxic Shellfish Poisoning (NSP), Ciguatera Fish Poisoning (CFP), Azaspiracid Shellfish Poisoning (AZP), and Amnesiac Shellfish Poisoning (ASP). The causative agents of these specific poisonings along with their biosyntheses are discussed in this review. The highly unusual and complex structures of most common seafood toxins have made them interesting targets for biosynthetic studies. Many of the toxins presented are biosynthesized via complex pathways that have been elucidated either through isotope labelled precursor feeding studies and/or characterization of the genes encoding the producing organism's biosynthetic machinery. Feeding studies key to our understanding of a particular toxin's biosynthesis, such as the incorporation of unusual precursors, as well as unique biosynthetic pathways and rare chemical mechanisms involved in the assembly process are highlighted. More recently, however, modern genomics-based techniques have been used for the elucidation of biosynthetic pathways and these are presented in the context of polyketide, non-ribosomal peptide, and hybrid pathway derived, toxin assembly. PMID:19761784

Kalaitzis, John A; Chau, Rocky; Kohli, Gurjeet S; Murray, Shauna A; Neilan, Brett A

2010-08-15

56

Overview of naturally occurring Earth materials and human health concerns  

NASA Astrophysics Data System (ADS)

The biosphere and the Earth's critical zone have maintained a dynamic equilibrium for more than 3.5 billion years. Except for solar energy, almost all terrestrial substances necessary for life have been derived from near-surface portions of the land, hydrosphere, and atmosphere. If aggregate biological activities are less than the rate of nutrient supply and/or resource renewal, sustained population growth is possible. Where the replenishment rate of a life-sustaining Earth material is finite, usage may reach a condition of dynamic equilibrium in which biological consumption equals but on average cannot exceed the overall supply. Although large, most natural resources are present in finite abundances; for such commodities, excessive present-day human utilization reduces future availability, and thus the ultimate planetary carrying capacity for civilization. Intensive use of Earth materials has enhanced the quality of life, especially in the developed nations. Still, natural background levels, and Earth processes such as volcanic eruptions, as well as human activities involving agriculture, construction, and the extraction, refining, and transformation of mineral resources have led to harmful side effects involving environmental degradation and public health hazards. Among naturally and anthropogenically induced risks are bioaccessible airborne dusts and gases, soluble pollutants in agricultural, industrial, and residential waters, and toxic chemical species in foods and manufactured products. At appropriate levels of ingestion, many Earth materials are necessary for existence, but underdoses and overdoses have mild to serious consequences for human health and longevity. This overview briefly sketches several natural resource health hazards. Included are volcanic ash + aerosols + gases, mineral dusts, non-volcanic aerosols + nanoparticles, asbestos + fibrous zeolites, arsenic, fluorine, iodine, uranium + thorium + radium + radon + polonium, selenium, mercury, copper, lead, chromium, and cadmium. Also noted are health effects of natural disasters, and an obligatory future sustainable consumption of natural resources. Not treated are the overwhelming adverse effects of malnutrition, lack of potable water, inadequate sanitation, fossil fuel usage, mining, manufacturing, and agricultural pollution, or environmental pathogens, nor are the important impacts of complex mixtures of Earth materials considered. With rise of the worldwide information network, economic globalization, and the industrial thrust of Developing Nations, the achievement of natural resource sustainability has emerged as a strategic imperative. Accompanying increased rates of Earth materials consumption and attendant environmental change, substantially improved, universal public health will require a major global effort, integrating collaborations among geoscientists, medical researchers, and epidemiologists. Governments and NGOs must provide important support of such cooperative efforts, and both health and Earth scientists must cross disciplinary and national boundaries.

Ernst, W. G.

2012-10-01

57

Biomimetic Nitration of Conjugated Linoleic Acid: Formation and Characterization of Naturally Occurring Conjugated Nitrodienes  

PubMed Central

Nitro-conjugated linoleic acids (NO2-cLA), endogenous nitrodiene lipids which act as inflammatory signaling mediators, were isolated and single isomers purified from the biomimetic acidic nitration products of conjugated linoleic acid (CLA). Structures were elucidated by means of detailed NMR and HPLCMS/MS spectroscopic analysis and the relative double bond configurations assigned. Additional synthetic methods produced useful quantities and similar isomeric distributions of these unusual and reactive compounds for biological studies and isotopic standards, and the potential conversion of nitro-linoleic to nitro-conjugated linoleic acids was explored via a facile base-catalyzed isomerization. This represents one of the few descriptions of naturally occurring conjugated nitro dienes (in particular, 1-nitro 1,3-diene), an unusual and highly reactive motif with few biological examples extant. PMID:24350701

Woodcock, Steven R.; Salvatore, Sonia R.; Bonacci, Gustavo; Schopfer, Francisco J.; Freeman, Bruce A.

2014-01-01

58

Evidence of autoinducer activity in naturally occurring biofilms  

Microsoft Academic Search

N-Acyl homoserine lactone (AHL) molecules have been shown to act as mediators of population density-dependent (quorum-sensing) gene expression in numerous Gram-negative bacteria. Functions associated with AHL include light production in Vibrio fischeri, expression of virulence factors in Pseudomonas aeruginosa, and conjugation in Agrobacterium tumefaciens. In nature, bacteria often grow as surface-adherent biofilm communities. As biofilms typically contain high concentrations of

Robert J. C McLean; Marvin Whiteley; David J Stickler; W. Claiborne Fuqua

1997-01-01

59

The Frequency, Nature, and Effects of Naturally Occurring Appearance-Focused Social Comparisons  

ERIC Educational Resources Information Center

This research examined the effects of naturally occurring appearance-focused social comparisons on women's affect, body satisfaction, and weight-related cognitions. During their daily activities, women reporting body dissatisfaction (n = 53) and women reporting body satisfaction (n = 34) recorded their reactions to comparison information.

Leahey, Tricia M.; Crowther, Janis H.; Mickelson, Kristin D.

2007-01-01

60

Naturally occurring C-terminal splice variants of nuclear receptors.  

PubMed

Alternative mRNA splicing in the region encoding the C-terminus of nuclear receptors results in receptor variants lacking the entire ligand-binding domain (LBD), or a part of it, and instead contain a sequence of splice variant-specific C-terminal amino acids. A total of thirteen such splice variants have been shown to occur in vertebrates, and at least nine occur in humans. None of these receptor variants appear to be able to bind endogenous ligands and to induce transcription on promoters containing the response element for the respective canonical receptor variant. Interestingly, ten of these C-terminal splice variants have been shown to display dominant-negative activity on the transactivational properties of their canonical equivalent. Research on most of these splice variants has been limited, and the dominant-negative effect of these receptor variants has only been demonstrated in reporter assays in vitro, using transiently transfected receptors and reporter constructs. Therefore, the in vivo function and relevance of most C-terminal splice variants remains unclear. By reviewing the literature on the human glucocorticoid receptor beta-isoform (hGRbeta), we show that the dominant-negative effect of hGRbeta is well established using more physiologically relevant readouts. The hGR beta-isoform may alter gene transcription independent from the canonical receptor and increased hGRbeta levels correlate with glucocorticoid resistance and the occurrence of several immune-related diseases. Thus, available data suggests that C-terminal splice variants of nuclear receptors act as dominant-negative inhibitors of receptor-mediated signaling in vivo, and that aberrant expression of these isoforms may be involved in the pathogenesis of a variety of diseases. PMID:19636396

van der Vaart, Michiel; Schaaf, Marcel J M

2009-01-01

61

Structures and Properties of Naturally Occurring Polyether Antibiotics  

PubMed Central

Polyether ionophores represent a large group of natural, biologically active substances produced by Streptomyces spp. They are lipid soluble and able to transport metal cations across cell membranes. Several of polyether ionophores are widely used as growth promoters in veterinary. Polyether antibiotics show a broad spectrum of bioactivity ranging from antibacterial, antifungal, antiparasitic, antiviral, and tumour cell cytotoxicity. Recently, it has been shown that some of these compounds are able to selectively kill cancer stem cells and multidrug-resistant cancer cells. Thus, they are recognized as new potential anticancer drugs. The biological activity of polyether ionophores is strictly connected with their molecular structure; therefore, the purpose of this paper is to present an overview of their formula, molecular structure, and properties. PMID:23586016

Rutkowski, Jacek; Brzezinski, Bogumil

2013-01-01

62

Isolation and Spectral Analysis of Naturally Occurring Thiarubrine A  

NASA Astrophysics Data System (ADS)

We have designed an experiment in which students isolate and characterize thiarubrine A, a pseudo-antiaromatic 1,2-dithia-3,5-cyclohexadiene derivative. Thiarubrines are an important class of compounds which have recently received attention because of their unusual reactivity, unique biological activity, and potential medicinal applications. They possess a distinctive red color and structure features that are particularly useful for demonstrating UV-vis, NMR, and IR spectral analyses. A crude mixture containing thiarubrine A is obtained by methanol (liquid-solid) extraction of the roots of short ragweed, Ambrosia artemisiifolia. Alternatively, these compounds can be isolated from numerous taxa within the family Asteraceae. Thiarubrine A possesses alkyl, alkenyl, and alkynyl functionality, which is useful in illustrating the utility of IR and NMR in the characterization of natural products. The long wavelength UV-vis absorption band of thiarubrine is indication of the nonplanarity of dithiin ring and provides an excellent opportunity to discuss the concepts of aromaticity, conjugation, and molecular orbital theory.

Reyes, Juan; Morton, Melita; Downum, Kelsey; O'Shea, Kevin E.

2001-06-01

63

Naturally occurring compounds affect glutamatergic neurotransmission in rat brain.  

PubMed

Natural products, including those derived from plants, have largely contributed to the development of therapeutic drugs. Glutamate is the main excitatory neurotransmitter in the central nervous system and it is also considered a nociceptive neurotransmitter, by acting on peripheral nervous system. For this reason, in this study we investigated the effects of the hydroalcoholic extracts from Drymis winteri (polygodial and drimanial), Phyllanthus (rutin and quercetine), Jathopha elliptica (jatrophone), Hedyosmum brasiliense (13HDS), Ocotea suaveolens (Tormentic acid), Protium kleinii (alphabeta-amyrin), Citrus paradise (naringin), soybean (genistein) and Crataeva nurvala (lupeol), described as having antinociceptive effects, on glutamatergic transmission parameters, such as [(3)H]glutamate binding, [(3)H]glutamate uptake by synaptic vesicles and astrocyte cultures, and synaptosomal [(3)H]glutamate release. All the glutamatergic parameters were affected by one or more of these compounds. Specifically, drimanial and polygodial presented more broad and profound effects, requiring more investigation on their mechanisms. The putative central side effects of these compounds, via the glutamatergic system, are discussed. PMID:17577666

Martini, Lucia Helena; Jung, Fernanda; Soares, Felix Antunes; Rotta, Liane Nanci; Vendite, Deusa Aparecida; Frizzo, Marcos Emilio dos Santos; Yunes, Rosendo A; Calixto, Joo Batista; Wofchuk, Susana; Souza, Diogo O

2007-11-01

64

Naturally occurring and synthetic peptides acting on nicotinic acetylcholine receptors.  

PubMed

Nicotinic acetylcholine receptors (nAChRs) are pentameric membrane-bound proteins belonging to the large family of ligand-gated ion channels. nAChRs possess various binding sites which interact with compounds of different chemical nature, including peptides. Historically first peptides found to act on nAChR were synthetic fragments of snake alpha-neurotoxins, competitive receptor antagonists. Later it was shown that fragments of glycoprotein from rabies virus, having homology to alpha-neurotoxins, and polypeptide neurotoxins waglerins from the venom of Wagler's pit viper Trimeresurus (Tropidolaemus) wagleri bind in a similar way, waglerins being efficient blockers of muscle-type nAChRs. Neuropeptide substance P appears to interact with the channel moiety of nAChR. beta-Amyloid, a peptide forming senile plaques in Alzheimer's disease, also can bind to nAChR, although the mode of binding is still unclear. However, the most well-studied peptides interacting with the ligand-binding sites of nAChRs are so-called alpha-conotoxins, peptide neurotoxins from marine snails of Conus genus. First alpha-conotoxins were discovered in the late 1970s, and now it is a rapidly growing family due to isolation of peptides from multiple Conus species, as well as to cloning, and chemical synthesis of new analogues. Because of their unique selectivity towards distinct nAChR subtypes, alpha-conotoxins became valuable tools in nAChR research. Recent X-ray structures of alpha-conotoxin complexes with acetylcholine-binding protein, a model of nAChR ligand-binding domains, revealed the details of the nAChR ligand-binding sites and provided the basis for design of novel ligands. PMID:19601841

Kasheverov, Igor E; Utkin, Yuri N; Tsetlin, Victor I

2009-01-01

65

Distribution of naturally occurring radionuclides (U, Th) in Timahdit black shale (Morocco).  

PubMed

Attention has been focused recently on the use of Moroccan black oil shale as the raw material for production of a new type of adsorbent and its application to U and Th removal from contaminated wastewaters. The purpose of the present work is to provide a better understanding of the composition and structure of this shale and to determine its natural content in uranium and thorium. A black shale collected from Timahdit (Morocco) was analyzed by powder X-ray diffraction and SEM techniques. It was found that calcite, dolomite, quartz and clays constitute the main composition of the inorganic matrix. Pyrite crystals are also present. A selective leaching procedure, followed by radiochemical purification and alpha-counting, was performed to assess the distribution of naturally occurring radionuclides. Leaching results indicate that 238U, 235U, 234U, 232Th, 230Th and 228Th have multiple modes of occurrence in the shale. U is interpreted to have been concentrated under anaerobic conditions. An integrated isotopic approach showed the preferential mobilization of uranium carried by humic acids to carbonate and apatite phases. Th is partitioned between silicate minerals and pyrite. PMID:17098337

Galindo, C; Mougin, L; Fakhi, S; Nourreddine, A; Lamghari, A; Hannache, H

2007-01-01

66

INFLUENCE OF EASILY DEGRADABLE NATURALLY OCCURRING CARBON SUBSTRATES ON BIODEGRADATION OF MONOSUBSTITUTED PHENOLS BY AQUATIC BACTERIA  

EPA Science Inventory

The influence of readily degradable, naturally occurring carbon substrates on the biodegradation of several monosubstitued phenols (m-cresol, m-aminophenol, p-chlorophenol) was examined. The natural substrate classes used were amino acids, carbohydrates, and fatty acids. Samples ...

67

Polyion complex libraries possessing naturally occurring differentiation for pattern-based protein discrimination.  

PubMed

Polyion complexes with naturally occurring differentiation of enzymes serve to create receptor libraries with high differentiability and lower synthetic demands for pattern-based protein discrimination. PMID:24080832

Tomita, Shunsuke; Yoshimoto, Keitaro

2013-11-14

68

Isotope fractionation during natural gas hydrate formation  

NASA Astrophysics Data System (ADS)

In the task of pursuing the origin of hydrate-bound gas, isotope analysis is a well established tool of prediction. The carbon isotope values of methane, ethane, propane and i-butane will strongly indicate the source to either be microbial, thermogenic or of mixed origin. This is due to kinetic fractionation during microbial activity. In microbial CO2 reduction, the microbes tend to reduce ?12C molecules preferentially to ?13C. This leads to light methane and ethane in the gas from microbial activity compared to methane and ethane of thermogenic origin. Recently, isotopically light methane and ethane from hydrate-bond gas from the pockmark field of Nyegga (Norwegian Sea) has been reported. The gas has migrated from a free gas system beneath the base of gas hydrate stability and reached the seafloor through a chimney structured migration feature. The free gas layer is thought to be supported by deeper sources, and polygonal faulting that is known to lay on top of petroleum reservoirs supports speculations that the free gas layer contains thermogenic gas. The isotopic evidence classifies the hydrate gas as fractionated by microbial activity, while the composition and geological setting tell tales of a thermogenic source. This conundrum has led to the speculation upon a fractionation of carbon isotope through hydrate formation. With an experimental setup consisting of a cooling incubator and a pressure cell with controlled torque stirring, hydrates can form under controlled pressure and temperature conditions. The gas hydrates are formed with excess of gas making it possible to sample both the excess gas and hydrate gas. The gas is 99.5 % methane,

Nesheim Vaular, Espen; Corak, Djurdjica; Barth, Tanja

2010-05-01

69

REMOVAL OF ARSENIC FROM GROUNDWATER USING NATURALLY OCCURRING IRON OXIDES IN RURAL REGIONS OF MONGOLIA  

EPA Science Inventory

We have found that the iron oxide particles produced by grinding naturally occurring iron ores are very effective in removing arsenic from water. The arsenic adsorption isothermal of the particles h...

70

DECIPHERING NATURALLY-OCCURRING PB CONTAMINATION IMPACTING DRINKING WATER WELLS: SHAKER VILLAGE CATCHMENT, MAINE.  

EPA Science Inventory

Trace Pb concentrations in groundwater within glacial deposits across Maine fluctuate considerably. Deciphering the distribution and sources of naturally occurring Pb in groundwater with only the use of conventional anomaly identification techniques presents a challenge. In a rep...

71

In-situ remediation of naturally occurring radioactive materials with high-permeability hydraulic fracturing  

E-print Network

This thesis addresses the problem of removal of Naturally Occurring Radioactive Materials, NORM, and describes an effective alternative to the current treatment method for their removal. High-pen-meability fracturing, recently established...

Demarchos, Andronikos Stavros

2012-06-07

72

Naturally occurring nitrosatable amines. II. Secondary amines in tobacco and cigarette smoke condensate  

Microsoft Academic Search

The previously described method for isolation and identification of naturally occurring secondary amines has been applied to tobacco and cigarette smoke condensate (''tar''). Pyrrolidine and dimethylamine are the predominant amines found in both substances.

George M. Singer; William Lijinsky

1976-01-01

73

Regional Patterns in the Isotopic Composition of Natural and  

E-print Network

Mobilization of natural nitrate (NO3 -) deposits in the subsoil by irrigation water in arid and semiaridRegional Patterns in the Isotopic Composition of Natural and Anthropogenic Nitrate in Groundwater variation in soils, vegetation, topography, and moisture conditions. Introduction Nitrate (NO3 -) is one

74

Standards for stable isotope measurements in natural compounds  

Microsoft Academic Search

RESEARCH based on stable isotope variations in natural compounds is expanding in scientific fields such as geochemistry, hydrology, environmental studies and biochemistry. However, intercomparison of results obtained in different laboratories is often not fully reliable and therefore to improve the intercalibration of deuterium and 18O measurements in natural waters, two water standards have been distributed by the International Atomic Energy

R. Gonfiantini

1978-01-01

75

Ginsenoside Metabolites, Rather Than Naturally Occurring Ginsenosides, Lead to Inhibition of Human Cytochrome P450 Enzymes  

Microsoft Academic Search

There is still an argument about ginseng-prescription drug interactions. To evaluate the influence on cytochrome P450 (P450) activities of ginseng in the present study, the influence on P450 activities of naturally occurring ginsenosides and their degrada- tion products in human gut lumen was assayed by using human liver microsomes and cDNA-expressed CYP3A4. The results showed that the naturally occurring ginsenosides

Yong Liu; Jiang-Wei Zhang; Wei Li; Hong Ma; Jie Sun; Mai-Cun Deng; Ling Yang

2006-01-01

76

The isotopic effects of electron transfer: an explanation for Fe isotope fractionation in nature  

NASA Astrophysics Data System (ADS)

Recent developments in mass spectrometry techniques have created opportunities to examine the partitioning behavior of stable isotopes of transition metals with a focus on application to iron isotopes. Iron oxidizing and reducing bacteria have been shown to cause isotope fractionations similar in magnitude to those observed in sedimentary environments and it is believed that biological activity is responsible for the most significant Fe isotope fractionation in natural settings. Debate over the use of Fe isotopes as a biological marker resulted from subsequent measurements of fractionations in a variety of abiotic systems. The accumulated evidence, in both biotic and abiotic systems, points to a connection between redox processes and Fe isotope fractionation, however the exact mechanism for isotope fractionation is not yet well understood. Here, we present both a newly-developed theory based on chemical kinetics and preliminary experimental results that quantitatively delineate the relationship between driving force in a charge transfer reaction and resulting Fe isotope fractionation. The theory, based on R. Marcus's chemical kinetics theory for electron transfer (Ann. Rev. Phys. Chem. 15 (1964), 155), predicts that fractionation increases linearly with driving force with a proportionality related to two factors: the difference between isotopic equilibrium exchange of products and reactants, and the reorganization energy along the reaction coordinate. The theoretical predictions were confirmed by measurements of isotopic fractionation associated with electroplating iron metal from a ferrous chloride solution. Isotope fractionation of Fe electroplated under potentiostatic conditions was measured as a function of applied electrochemical potential. As plating voltage was varied from -50 mV to -2.0 V, the isotopic signature of the electroplated iron became depleted in heavy Fe, with ? 56Fe values ranging from -0.106(0.01) to -2.290(0.006) , and corresponding ? 57Fe values of -0.145(.011) and -3.354(.019) . The slope of the line created by plotting ? 56Fe vs ? 57Fe is equal to 0.6723(.0032), consistent with fractionation due to a kinetic process involving unsolvated iron atoms. This study demonstrates that there is a voltage-dependent isotope fractionation associated with the reduction of iron. The magnitude of fractionation is similar to observations of Fe reduction by certain bacteria, suggesting that electrochemical processes may be responsible for observed biogeochemical signatures. Charge transfer is a fundamental physicochemical process involving Fe as well as other transition metals with multiple isotopes. Partitioning of isotopes among elements with varying redox states holds promise as a tool in a wide range of the Earth and environmental sciences, biology, and industry.

Kavner, A.; Shahar, A.; Bonet, F.; Simon, J. I.; Young, E.

2004-12-01

77

Mass fractionation of noble gases in synthetic methane hydrate: Implications for naturally occurring gas hydrate dissociation  

USGS Publications Warehouse

As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings may presently be dissociating and releasing methane and other gases to the ocean-atmosphere system. A key challenge in assessing the impact of dissociating gas hydrates on global atmospheric methane is the lack of a technique able to distinguish between methane recently released from gas hydrates and methane emitted from leaky thermogenic reservoirs, shallow sediments (some newly thawed), coal beds, and other sources. Carbon and deuterium stable isotopic fractionation during methane formation provides a first-order constraint on the processes (microbial or thermogenic) of methane generation. However, because gas hydrate formation and dissociation do not cause significant isotopic fractionation, a stable isotope-based hydrate-source determination is not possible. Here, we investigate patterns of mass-dependent noble gas fractionation within the gas hydrate lattice to fingerprint methane released from gas hydrates. Starting with synthetic gas hydrate formed under laboratory conditions, we document complex noble gas fractionation patterns in the gases liberated during dissociation and explore the effects of aging and storage (e.g., in liquid nitrogen), as well as sampling and preservation procedures. The laboratory results confirm a unique noble gas fractionation pattern for gas hydrates, one that shows promise in evaluating modern natural gas seeps for a signature associated with gas hydrate dissociation.

Hunt, Andrew G.; Stern, Laura; Pohlman, John W.; Ruppel, Carolyn; Moscati, Richard J.; Landis, Gary P.

2013-01-01

78

Apoptosis and autophagy induction as mechanism of cancer prevention by naturally occurring dietary agents  

PubMed Central

Nontoxic naturally occurring compounds, especially those from dietary sources, are receiving increasing consideration for prevention and treatment of diseases including cancer. There is a growing need for innovative anticancer therapies and therefore search for natural compounds with novel biological activities or antineoplastic potential is currently an important area in drug discovery. Support for this interest also comes from increasing concern over the efficacy and safety of many conventional therapies, especially those that run over a long course of time. Laboratory studies in different in vitro and in vivo systems have shown that many natural compounds possess the capacity to regulate response to oxidative stress and DNA damage, suppress angiogenesis, inhibit cell proliferation and induce autophagy and apoptosis. This review discusses the induction of apoptosis and autophagy as a mechanism of cancer prevention by some of the most studied naturally occurring dietary compounds. PMID:23140293

Mukhtar, Eiman; Adhami, Vaqar Mustafa; Khan, Naghma; Mukhtar, Hasan

2013-01-01

79

Characterization of Contaminant Transport Using Naturally-Occurring U-Series Disequilibria  

SciTech Connect

Study the migration of nuclear waste contaminants in subsurface fractured systems using naturally occurring uranium and thorium-series radionuclides as tracers under in-situ physico-chemical and hydrogeologic conditions. Radioactive disequilibria among members of these decay-series nuclides can provide information on the rates of adsorption-desorption and transport of contaminants as well as on fluid transport and rock dissolution in a natural setting.

TEH-LUNG KU

2001-06-01

80

Recent progress regarding the bioactivities, biosynthesis and synthesis of naturally occurring resorcinolic macrolides.  

PubMed

Macrolides, which comprise a family of lactones with different ring sizes, belong to the polyketide class of natural products. Resorcinolic macrolides, an important subgroup, possess interesting structures and exhibit a wide variety of bioactivities, such as anti-tumor, anti-bacteria, and anti-malaria activities, etc. This review summarizes progress in isolation, bioactivity studies, biosynthesis, and representative chemical syntheses of this group of macrolides in recent decades, encompassing 63 naturally occurring macrolides published in 120 articles. PMID:24464049

Xu, Jing; Jiang, Cheng-shi; Zhang, Zai-long; Ma, Wen-quan; Guo, Yue-wei

2014-03-01

81

School-Age Children's Attributions About Their Own Naturally Occurring Minor Injuries: A Process Analysis  

Microsoft Academic Search

Objective: To analyze children's attribution of cause regarding their naturally occurring minor injuries in light of the pre-injury parental acceptability of children's behavior and the emotions children experienced immediately after the event. Method: Sixty-one 8-year-old children were interviewed biweekly for one year about their naturally oc- curring minor injuries. Participants monitored environmental and psychosocial elements of the injuries and later

Sara Gable; Lizette Peterson

1998-01-01

82

Residential Proximity to Naturally Occurring Asbestos and Mesothelioma Risk in California  

Microsoft Academic Search

Rationale: Little is known about environmental exposure to low levels of naturally occurring asbestos (NOA) and malignant meso- thelioma (MM) risk. Objectives: To conduct a cancer registry-based case control study of residential proximity to NOA with MM in California. Methods: Incident MM cases (n 2,908) aged 35 yr or more, diag- nosed between 1988 and 1997, were selected from the

Xue-lei Pan; Howard W. Day; Wei Wang; Laurel A. Beckett; Marc B. Schenker

2005-01-01

83

Caffeine and Related Methylxanthines: Possible Naturally Occuring Pesticides Author(s): James A. Nathanson  

E-print Network

Caffeine and Related Methylxanthines: Possible Naturally Occuring Pesticides Author(s): James A Accessed: 02/12/2009 08:17 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms

Cooper, Robin L.

84

Sign languages are naturally occurring languages used by members of deaf communities throughout the world.  

E-print Network

Sign languages are naturally occurring languages used by members of deaf communities throughout, New Haven, Connecticut We investigated effects of sign language experience on deaf and hearing-spreading).AXB discrimination andAXB categorization and goodness ratings on the target items were completed by deaf early

85

A radioimmunological assay for naturally occurring insect juvenile hormones using iodinated tracers  

E-print Network

A radioimmunological assay for naturally occurring insect juvenile hormones using iodinated tracers hormone (JH). The antigens were prepared by binding the JH's to human serum albumin. lodinated tracers.100 of BSA. The assay detection limit was 20 pg for all the three juvenile hormones. RIA sensitivity

Paris-Sud XI, Université de

86

Genome-wide architecture of reproductive isolation in a naturally occurring hybrid zone between Mus  

E-print Network

house mouse subspecies (Mus musculus musculus and M. m. domesticus) along with studies using laboratoryGenome-wide architecture of reproductive isolation in a naturally occurring hybrid zone between Mus musculus musculus and M. m. domesticus VA´ CLAV JANOUS EK,* LIUYANG WANG, KEN LUZYNSKI, PETRA DUFKOVA

Dean, Matthew D.

87

Gene Conversion is Involved in the Transfer of Genetic Information Between Naturally Occurring Inversions of Drosophila  

Microsoft Academic Search

The DNA sequences of the ribosomal protein 49 (rp49) region were determined for 34 isochromosomal strains of Drosophila subobscura representing two chromosomal arrangements, the OST and the O3+4 gene arrangements, which differ by two overlapping inversions. The data reveal that gene conversion is a mechanism responsible for the transfer of genetic information between naturally occurring inversions of Drosophila. The estimated

Julio Rozas; Montserrat Aguade

1994-01-01

88

Comparison of naturally occurring shale bitumen asphaltene and retorted shale oil asphaltene  

Microsoft Academic Search

Asphaltene is ubiquitously present in both the natural occurring bitumen and the retorted shale oil. Very few cases for the comparison of asphaltene properties are available in the literature. In this research, a comparison of the shale bitumen asphaltene and the retorted shale oil asphaltene was undertaken to investigate structural changes during thermal cracking. This was accomplished by means of

F. F. Shue; T. F. Yen

1980-01-01

89

A naturally occurring horizontal gene transfer from a eukaryote to a prokaryote  

Microsoft Academic Search

Summary Naturally occurring horizontal gene transfers between nonviral organisms are difficult to prove. Only with the availability of sequence data from a wide variety of organisms can a convincing case be made. In the case of putative gene transfers between prokaryotes and eukaryotes, the minimum requirements for inferring such an event include (1) sequences of the transferred gene or its

R. F. Doolittle; D. F. Feng; K. L. Anderson; M. R. Alberro

1990-01-01

90

Photoprotection: part I. Photoprotection by naturally occurring, physical, and systemic agents.  

PubMed

The acute and chronic consequences of ultraviolet radiation on human skin are reviewed. An awareness of variations in naturally occurring photoprotective agents and the use of glass, sunglasses, and fabric can lead to effective protection from the deleterious effects of ultraviolet radiation. New systemic agents, including Polypodium leucotomos, afamelanotide, and antioxidants have potential as photoprotective agents. PMID:24238179

Jansen, Rebecca; Wang, Steven Q; Burnett, Mark; Osterwalder, Uli; Lim, Henry W

2013-12-01

91

On Their Own Turf: Community Design and Active Aging in a Naturally Occurring Retirement Community  

Microsoft Academic Search

This research examines neighborhood-scale physical and social environmental conditions that are associated with active living among seniors in Greendale, Wisconsin. The town's demographics reflect a naturally occurring retirement community. From survey responses of over 700 seniors, findings show that far more seniors reported walking for health and exercise reasons than for instrumental reasons or for social interaction. Senior Greendalers rarely

Sherry Ahrentzen

2010-01-01

92

NATURALLY OCCURRING SECONDARY NUTRITIONAL HYPERPARATHYROIDISM IN CATTLE EGRETS (BUBULCUS IBIS) FROM CENTRAL TEXAS  

Microsoft Academic Search

Naturally occurring secondary nutritional hyperparathyroidism is described in the nestlings of two colonies of cattle egrets (Bubulcus ibis) from Central Texas (Bryan and San Antonio, Texas, USA). Nestlings from a third colony (Waco, Texas, USA) were collected in a subsequent year for comparison. Birds from the first two colonies consistently had severe osteo- penia and associated curving deformities and folding

David N. Phalen; Mark L. Drew; Cindy Contreras; Kimberly Roset; Miguel Mora

93

The Importance of Pharmacokinetic Principles in Characterizing Carcinogenic Thresholds for Naturally Occurring and Synthetic Chemicals  

Microsoft Academic Search

Many chemicals, both man-made and naturally occuring, can elicit a carcinogenic response either as a mutagenic response in vitro or as a frank tumor in vivo. In both instances emphasis has been placed historically on the dose which elicits the response. When the carcinogenic response is related to the pharmacokinetics of the carcinogen taking into account the dose, the frequency

David W. Yesair

1983-01-01

94

Simulating dynamic load of naturally occurring TOC from watershed into a river  

Microsoft Academic Search

Naturally occurring total organic carbon (TOC) is an important feature of stream water quality. This study investigates the dynamic load of TOC from the deep creek watershed into the lower St. Johns River (LSJR), FL, USA, using numerical simulations and field measurements. An existing St. Johns River watershed assessment model for simultaneous loading of nutrients from watersheds into rivers is

Ying Ouyang

2003-01-01

95

Fundamental studies on kinetic isotope effect (KIE) of hydrogen isotope fractionation in natural gas systems  

USGS Publications Warehouse

Based on quantum chemistry calculations for normal octane homolytic cracking, a kinetic hydrogen isotope fractionation model for methane, ethane, and propane formation is proposed. The activation energy differences between D-substitute and non-substituted methane, ethane, and propane are 318.6, 281.7, and 280.2cal/mol, respectively. In order to determine the effect of the entropy contribution for hydrogen isotopic substitution, a transition state for ethane bond rupture was determined based on density function theory (DFT) calculations. The kinetic isotope effect (KIE) associated with bond rupture in D and H substituted ethane results in a frequency factor ratio of 1.07. Based on the proposed mathematical model of hydrogen isotope fractionation, one can potentially quantify natural gas thermal maturity from measured hydrogen isotope values. Calculated gas maturity values determined by the proposed mathematical model using ??D values in ethane from several basins in the world are in close agreement with similar predictions based on the ??13C composition of ethane. However, gas maturity values calculated from field data of methane and propane using both hydrogen and carbon kinetic isotopic models do not agree as closely. It is possible that ??D values in methane may be affected by microbial mixing and that propane values might be more susceptible to hydrogen exchange with water or to analytical errors. Although the model used in this study is quite preliminary, the results demonstrate that kinetic isotope fractionation effects in hydrogen may be useful in quantitative models of natural gas generation, and that ??D values in ethane might be more suitable for modeling than comparable values in methane and propane. ?? 2011 Elsevier Ltd.

Ni, Y.; Ma, Q.; Ellis, G.S.; Dai, J.; Katz, B.; Zhang, S.; Tang, Y.

2011-01-01

96

The analysis of naturally-occurring radionuclides from uranium and thorium decay series in table mineral waters.  

PubMed

This project required the highly sensitive analysis of low-level alpha- and beta-emitters naturally occurring in table mineral water sold on the Swiss market. These radionuclides occur in the three major decay series-uranium-238, uranium-235, and thorium-232. The radionuclides analysed were 238U, 235U, 234U, 232Th, 230Th, 228Th, 210Po, 210Pb, and 226Ra. Many other radionuclides were determinable as a result of their equilibrium with an analysed nuclide. Efficient, element specific separation techniques were developed, allowing for the spectral analysis of each element without interference from other radioactive elements. Radioactive tracers, 232U, 230Th, and 209Po, were necessary to determine the percentage yield. These yields often varied greatly between different mineral waters, especially for thorium, ranging from 30 to 100%. Uranium, thorium and polonium isotopes could be directly analysed for by alpha-spectrometry. 226Ra was determined through the ingrowth of its daughter 222Rn by liquid scintillation counting. From the samples remaining after 210Po removal, the isotope's re-ingrowth from 210Pb determined the original 210Pb content. Limits of detection ranged from 0.1 to 2.0 mBq/l. The following contents were determined 234U + 238U 30-720 mBq/l; 232Th + 230Th < 1-5 mBq/l; 228Th 2-40 mBq/l; 226Ra 5-370 mBq/l; 210Po 1-90 mBq/l; 2,0Pb 1-90 mBq/l. PMID:8469952

Aellen, T C; Umbricht, O; Goerlich, W

1993-03-25

97

Issues in the disposal of waste containing naturally occurring radioactive material.  

PubMed

This article considers a number of key issues in the disposal of waste containing enhanced levels of naturally occurring radioactive material (NORM), including gaseous, liquid and solid media. A brief review is made of sources of natural radioactivity in the biosphere and of anthropogenic enhancement of the concentration of NORM in the various media. The factors controlling the mobility of radionuclide activity in the environment are examined and disposal options are considered, comparison also being made with disposal of nuclear fuel cycle materials, in particular the tailings of uranium mining. Current and proposed disposal practices and policies for NORM are cited, reference being made to experiences in a number of countries. PMID:9451776

Bhattacharyya, D K

1998-03-01

98

Cardiovascular reactivity to a naturally occurring stressor: development and psychometric evaluation of a psychophysiological assessment procedure.  

PubMed

Three studies were conducted to examine the feasibility, reactive effects of assessment, stability, sampling parameters, and sensitivity of an assessment procedure designed to measure cardiovascular responses to a discrete, naturally occurring, and replicatable stressor--university course examinations. Undergraduate students monitored their blood pressure and heart rate several times during one or two classroom examinations and for several class sessions preceding each examination. Classroom examinations were generally associated with significant increases in subjective measures of distress and cardiovascular measures. Reactive effects of assessment and other sources of error were minimized and responses were reasonably stable over time. These results support the potential utility, validity, and cost-efficiency of this methodology for assessing cardiovascular reactivity to naturally occurring stressors. PMID:9429988

Hazlett, R L; Falkin, S; Lawhorn, W; Friedman, E; Haynes, S N

1997-12-01

99

Effect of fermentation on naturally occurring deoxynivalenol (DON) in Argentinean bread processing technology.  

PubMed

The stability of naturally occurring DON was evaluated during the fermentation stage of the bread-making process on a pilot scale. Two different products, French bread and Vienna bread, were prepared with naturally contaminated wheat flour (150 mg kg(-1)) under controlled experimental conditions. Dough was fermented at 30, 40 and 50 degrees C according to standard procedures employed in Argentinean low-technology bakeries. When the dough was fermented at 50 degrees C, the maximum reduction was 56% for the Vienna bread, with French bread being reduced by 41%. DON reduction during bread-making occurs not only in the baker due to thermal decomposition, but also during the fermentation step. The Argentinean traditional bread-making process might reduce DON levels during the fermentation stages if the dough is leavened at temperatures > 30 degrees C. PMID:11665728

Samar, M M; Neira, M S; Resnik, S L; Pacin, A

2001-11-01

100

Biosensors for rapid monitoring of primary-source drinking water using naturally occurring photosynthesis  

Microsoft Academic Search

Working with primary-source freshwater drinking samples from the Clinch and Tennessee Rivers, we have developed a tissue-based biosensor detection system that uses naturally occurring aquatic photosynthetic tissue as the sensing material for detection of chemical antagonists in the water. Sensor readout is based on well-known principles of fluorescence induction by living photosynthetic tissue. The Clinch River is the main source

Miguel Rodriguez; Charlene A. Sanders; Elias Greenbaum

2002-01-01

101

Effects of naturally occurring furanocoumarins on lipid peroxidation and carbon tetrachloride induced hepatotoxicity in mice  

Microsoft Academic Search

Several naturally occurring furanocoumarins significantly inhibited microsomal lipid peroxidation not only mediated by endogeneous\\u000a iron and NADPH but also initiated by CCl4 metabolites. Phellopterin, a potent inhibitor of cytochrome P-450, exhibited an almost complete inhibition of CCl4-induced hepatotoxicity as measured by sGPT activity 24 hr after CCl4 intoxication, whereas other furanocoumarins such as imperatorin, byakangelicin and oxypeucedanin methanolate exerted no

Kuk Hyun Shin; Won Sick Woo; Ki Ho Moon; Seung Jo Yoo

1993-01-01

102

Pyrethroid insecticides: A naturally occurring toxin. (Latest citations from Pollution Abstracts). Published Search  

SciTech Connect

The bibliography contains citations concerning the effects of pyrethrum and pyrethroid insecticides. Topics examine toxicity to fish, worms, flies, mosquitoes, and moths. Chemical residue on crops, the transportation of pyrethrum from soils to crops, and pyrethrum accumulation in ponds and lakes are among the topics discussed. Naturally occurring and synthetic pyrethroid insecticides are included. (Contains a minimum of 173 citations and includes a subject term index and title list.)

Not Available

1993-05-01

103

Properties of rigid-line inclusions as building blocks of naturally occurring composites  

Microsoft Academic Search

In the present work, rigid-line inclusions (also known as anticracks) are studied as a potential tool for the modelling of building blocks in naturally occurring composites. The choice of rigid-line inclusions is motivated by observations that the mineral phase in such composites as nacre, enamel, and silk consists of inclusions that have a flat plate-like shape and material properties that

Pawan Pingle; James Sherwood; Larissa Gorbatikh

2008-01-01

104

Hydroxytyrosol, a Natural Molecule Occurring in Olive Oil, Induces Cytochrome c-Dependent Apoptosis  

Microsoft Academic Search

2-(3,4-Dihydroxyphenyl)ethanol (DPE), a naturally occurring phenolic antioxidant molecule found in olive oil, has been reported to exert several biological and pharmacological activities. We studied the effect of this compound on the proliferation and survival of HL60 cell line. Concentrations from 50 to 100 ?M DPE, comparable to its olive oil content, caused a complete arrest of HL60 cell proliferation and

Fulvio Della Ragione; Valeria Cucciolla; Adriana Borriello; Valentina Della Pietra; Gabriele Pontoni; Luigi Racioppi; Caterina Manna; Patrizia Galletti; Vincenzo Zappia

2000-01-01

105

9-?-L(+) Adenosine: A new naturally occurring plant growth substance elicited by triacontanol in rice  

Microsoft Academic Search

The naturally occurring plant growth substance elicited by triacontanol was found to be 9--L(+) adenosine by physical and spectral methods. At picomolar concentrations, 9--L(+) adenosine stimulated growth as determined by dry weight measurements of several plant species. Reaction of adenosine deaminase with adenosine from rice showed that small quantities of 9--L(+) adenosine exist in plants. We believe this is the

Stanley Ries; Violet Wert; N. F. D. O'Leary; Muraleedharan Nair

1990-01-01

106

Intraspecific variation in testis asymmetry in birds: evidence for naturally occurring compensation  

PubMed Central

In many taxa, the left and right testes often differ in size. The compensation hypothesis states that one testis of the pair serves as a back-up for any reduced function in the other and provides a mechanism to explain intraspecific variation in degree and direction of gonad asymmetry. Although testis asymmetry is common in birds, evidence for natural testis compensation is unknown. Using a novel quantitative approach that can be applied to any bilateral organ or structure, we show that testis compensation occurs naturally in birds and can be complete when one testis fails to develop. Owing to a recurrent risk of testis impairment and an evolutionary trade-off between natural and sexual selections acting on the arrangement of internal organs in species with abdominal and/or seasonal testes, compensation adds an important, but neglected, dimension to measures of male reproductive investment. PMID:19324740

Calhim, Sara; Birkhead, Tim R.

2009-01-01

107

Isotopic identification of natural vs. anthropogenic sources of Pb in Laramie basin groundwaters, Wyoming, USA  

Microsoft Academic Search

Water well samples, precipitation, and leachates of aquifer rock samples from the Laramie basin, Wyoming, were analyzed to test the suitability of Pb isotopes for tracing hydrologic processes in a basin where Sr isotopes had proven effective. Leachable Pb from host rocks to aquifers in this basin have isotopically distinct compositions and isotopic tracing would be effective in differentiating natural

R. N. Toner; C. D. Frost; K. R. Chamberlain

2003-01-01

108

Soil-to-Crop Transfer Factors of Naturally Occurring Radionuclides and Stable Elements for Long-Term Dose Assessment  

SciTech Connect

A soil-to-crop transfer factor, TF, is a key parameter that directly affects the internal dose assessment for the ingestion pathway, however, obtaining TFs of various long-lived radionuclides occurred during operation of nuclear power plants is difficult because most of them could not be found in natural environments. In this study, therefore, we collected crops and their associated soils throughout Japan and measured more than 50 elements to obtain TFs under equilibrium conditions. The TFs were calculated for 42 elements (Li, Na, Mg, Al, Si, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Y, Mo, Cd, Sn, I, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tl, Pb, Th and U) from their concentrations in both crop and soil samples. The TF is defined as the concentration of an isotope in a crop (in Bq/kg or mg/kg dry weight) divided by the concentration of the isotope in soil (in Bq.kg or mg/kg dry weight). Probability distributions of TFs for 62 upland field crops were usually log-normal type so that geometric means (GMs) were calculated. The values for the elements of interest from the viewpoint of long-term dose assessment were 2.5E-02 for Se, 7.9E-02 for Sr, 3.1E-03 for Cs, 4.2E-04 for Th and 4.6E-04 for U. Leafy vegetable showed the highest TFs for all the elements among the crop groups. It was clear that these data were usually within the 95% confidence limits of TFs compiled by IAEA in Technical Report Series 364. (authors)

Uchida, S.; Tagami, K. [National Institute of Radiological Sciences, Inage-ku, Chiba (Japan)

2007-07-01

109

Articular Osteochondrosis: A Comparison of Naturally-Occurring Human and Animal Disease  

PubMed Central

Background Osteochondrosis (OC) is a common developmental orthopedic disease affecting both humans and animals. Despite increasing recognition of this disease among children and adolescents, its pathogenesis is incompletely understood because clinical signs are often not apparent until lesions have progressed to end-stage, and examination of cadaveric early lesions is not feasible. In contrast, both naturally-occurring and surgically-induced animal models of disease have been extensively studied, most notably in horses and swine, species in which OC is recognized to have profound health and economic implications. The potential for a translational model of human OC has not been recognized in the existing human literature. Objective The purpose of this review is to highlight the similarities in signalment, predilection sites and clinical presentation of naturally-occurring OC in humans and animals and to propose a common pathogenesis for this condition across species. Study Design Review Methods The published human and veterinary literature for the various manifestations of OC was reviewed. Peer-reviewed original scientific articles and species-specific review articles accessible in PubMed (US National Library of Medicine) were eligible for inclusion. Results A broad range of similarities exists between OC affecting humans and animals, including predilection sites, clinical presentation, radiographic/MRI changes, and histological appearance of the end stage lesion, suggesting a shared pathogenesis across species. Conclusion This proposed shared pathogenesis for OC between species implies that naturally-occurring and surgically-induced models of OC in animals may be useful in determining risk factors and for testing new diagnostic and therapeutic interventions that can be used in humans. PMID:23954774

McCoy, Annette M; Toth, Ferenc; Dolvik, Nils I; Ekman, Stina; Ellermann, Jutta; Olstad, Kristin; Ytrehus, Bjornar; Carlson, Cathy S

2013-01-01

110

Perchlorate isotope forensics with naturally produced 36Cl  

NASA Astrophysics Data System (ADS)

The source of perchlorate (ClO4-) in many surface and groundwaters is not known. Recent studies (Parker et al., 2008) suggest that natural production is widespread and common, and may involve atmospheric processes. The isotopic composition of perchlorate chlorine and oxygen has proven useful for identifying anthropogenic/natural perchlorate sources (Bohlke et al, 2005) and for exploring biodegradation in environmental samples (Sturchio et al, 2007). The stable isotope approach, however, requires processing very large volumes of water to obtain milligrams of rigorously separated perchlorate for analysis, limiting its widespread application. Chlorine-36 (36Cl) is a long-lived and rare radionuclide produced cosmogenically in the upper atmosphere. The measurement of 36Cl/Cl by accelerator mass spectrometry (AMS) only requires micrograms of sample chlorine enabling lower volume extractions (less than 1/10th that required for stable isotope techniques), and potentially less rigorous perchlorate chemistry. The primary technical goal of our work is to determine the utility of 36Cl in distinguishing perchlorate source and in constraining mechanisms of natural perchlorate formation. We expect that synthetic perchlorate compounds produced using chloride brines from ancient sources and concentrated modern deposits will have low 36Cl/Cl ratios that will be distinct from natural perchlorate produced in the atmosphere. High levels of 36Cl in groundwater or rainwater perchlorate would then be an unambiguous indication of a natural atmospheric production, and the distribution of 36Cl/Cl in precipitation and groundwater (in conjunction with stable isotope compositions) would constrain the mechanism for natural perchlorate production in the atmosphere. Using accelerator mass spectrometry (AMS), we have measured 36Cl/Cl in a number of synthetic perchlorate salts (including potassium, sodium, magnesium, and ammonium salts). Synthetic salt 36Cl/Cl atom ratios range from 1 to 35 e-15 (consistent with recently reported analyses in Sturchio et al., 2008), and are two to fifteen times the AMS background. Bohlke et al, 2005. Anal. Chem. 77, 7838-7842. Parker et al, 2008. Environ. Sci. Technol. 42, 1465-1471. Sturchio et al, 2007. Environ. Sci. Technol. 41, 2796-2802. Sturchio et al, 2008. 36Cl: Tracer of perchlorate origin? (abstr.)Goldschmidt 2008 (July 13-18, Vancouver, Canada). This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344

Hillegonds, D.; Parker, D.; Singleton, M.; Buchholz, B.; Esser, B.; Moran, J.; Rood, D.; Finkel, R.

2008-12-01

111

Bibliography of reports, papers, and presentations on naturally occurring radioactive material (NORM) in petroleum industry wastes  

SciTech Connect

This bibliography was created to support projects conducted by Argonne National Laboratory (ANL) addressing issues related to naturally occurring radioactive material (NORM) in petroleum industry wastes. The bibliography provides citations for many of the available published reports, papers, articles, and presentations on petroleum industry NORM. In the past few years, the rapid expansion of NORM treatment and disposal technologies, the efforts to characterize NORM wastes and their associated potential risks, and the promulgation of state-level NORM regulatory programs have been well-documented in project reports and in papers presented at technical conferences and symposia. There are 221 citations.

Smith, K.P.; Wilkey, M.L.; Hames, R.D.

1997-07-01

112

Occupational exposure due to naturally occurring radionuclide material in granite quarry industry.  

PubMed

The potential occupational exposure in granite quarry industry due to the presence of naturally occurring radioactive material (NORM) has been investigated. The activity concentrations of (40)K, (226)Ra and (232)Th were determined using gamma-ray spectroscopy method. The annual effective dose of workers through different exposure pathways was determined by model calculations. The total annual effective dose varied from 21.48 to 33.69 ?Sv y(-1). Inhalation dose contributes the highest to the total effective dose. The results obtained were much lower than the intervention exemption levels (1.0 mSv y(-1)) given in the International Commission on Radiological Protection Publication 82. PMID:21447506

Ademola, J A

2012-02-01

113

Synthesis and anti-cancer activity of naturally occurring 2,5-diketopiperazines.  

PubMed

Three naturally occurring oxyprenylated diketopiperazines were synthesized and preliminarily tested as growth inhibitory agents in vitro against various cancer cell lines. The compounds were tested on six human cancer cell lines with different sensitivity to proapoptotic stimuli using the MTT colorimetric assay. The data revealed that of the chemicals under study only deoxymicelianamide (11) displayed the highest activity, recording mean IC50 growth inhibitory values ranging from 2 to 23?M. A comparative study with the non-geranylated saturated derivative of (11) revealed the importance of the presence of the geranyloxy side chain and the exocyclic 2,5-DPK double bond moiety for the observed activity. PMID:25064216

Mollica, Adriano; Costante, Roberto; Fiorito, Serena; Genovese, Salvatore; Stefanucci, Azzurra; Mathieu, Veronique; Kiss, Robert; Epifano, Francesco

2014-10-01

114

Soft x-ray spectroscopy and microspectroscopy of magnetic and naturally occurring materials  

NASA Astrophysics Data System (ADS)

The ability to obtain spectral information about the electronic, chemical, and magnetic structure of a material on a micron sized spatial scale has been a premiere advantage to using an X-ray photoemission electron microscope (X-PEEM) at a synchrotron radiation facility. The micro-spectroscopic ability of the X-PEEM currently and the ease at which it can be transformed into a fall spectromicroscopy technique make it an ideal candidate for the future. To this end, presented is material from the two techniques, spectroscopy and microscopy, and a micro-spectroscopy study of the surface of a naturally occurring mineral Ilmenite. Results from the ligand field multiplet model calculations are presented along with a configuration interaction approach and compared with the experimentally measured spectra from a number of naturally occurring transition metal compounds of Mn and Fe. The interpretation with a ligand field multiplet model accounts well for the observed spectra and due to its simplicity this model yields accurate and well defined electronic structure parameters. Utilizing the X-ray magnetic circular dichroism (XMCD) the sum rules, we show that the spin to orbital moment for ultra-thin Fe films on Pd(001) and Ag(001) increase as the film thickness decreases but for Fe films grown on ferromagnetic substrates such as fcc Co and Ni the spin to orbital moment remains constant. We also show a dependence of the film coercivity on the amount of mismatch between the Fe overlayers and the substrate. It is theorized that this dramatic increase in the coercive field is due to mismatch dislocations which occur when the film is relaxing into its natural state. A link between anomalous uniaxial anisotropy displayed in ultra-thin films of fcc Co/Cu(001) and the magnetic domain structure is shown. A two-site simple model is used to explain the anomalous uniaxial anisotropy and a correlation between domain structure and underlying crystal topography is theorized. Finally, a case study of lamellar domains present in natural ilmenite is shown which combines the spatial resolution with spectroscopic data. High-resolution spectroscopy from these two different regions reveals fine structure from iron atoms in two different charge states, and titanium in a single phase. These results show that qualitative as well as quantitative surface chemistry studies can be performed on natural mineral samples using X-ray photoemission electron microscopy. (Abstract shortened by UMI.)

Droubay, Timothy Charles

115

A case of naturally occurring visual field loss in a chimpanzee with an arachnoid cyst.  

PubMed

Deficits in the occipital cortex have varying consequences among mammalian species. Such variations are indicative of evolutionary transitions in the striate cortical contribution to visually guided behavior. However, little is known about the role of the striate cortex in visually guided behavior in chimpanzees due to ethical concerns about invasive experiments and methodological limitations such as the inability to monitor gaze movements. We had the opportunity to study the behavioral consequences of a deficit in the occipital cortex in a chimpanzee with a naturally occurring arachnoid cyst in her right occipital lobe. We assessed the chimpanzee's ability to detect a small light probe (0.5 visual degree, Michelson contrast > 0.9) presented at several locations in the visual field while monitoring gaze direction using an infra-red remote eye-tracker recently introduced to studies of great apes. The results showed the chimpanzee was unable to detect the probe in the lower left quadrant of the visual field, suggesting severe loss of contrast sensitivity in a part of hemivisual field that is retinotopically corresponded to the hemisphere of the cyst. A chimpanzee with a naturally occurring deficit in the right striate cortex and the availability of remote eye-tracking technology presented a unique opportunity to compare the role of the occipital lobe in visually guided behavior among various primate species. PMID:24036355

Kaneko, Takaaki; Sakai, Tomoko; Miyabe-Nishiwaki, Takako; Tomonaga, Masaki

2013-11-01

116

Thermal resistance of naturally occurring airborne bacterial spores. [Viking spacecraft dry heat decontamination simulation  

NASA Technical Reports Server (NTRS)

Simulation of a heat process used in the terminal dry-heat decontamination of the Viking spacecraft is reported. Naturally occurring airborne bacterial spores were collected on Teflon ribbons in selected spacecraft assembly areas and subsequently subjected to dry heat. Thermal inactivation experiments were conducted at 105, 111.7, 120, 125, 130, and 135 C with a moisture level of 1.2 mg of water per liter. Heat survivors were recovered at temperatures of 135 C when a 30-h heating cycle was employed. Survivors were recovered from all cycles studied and randomly selected for identification. The naturally occurring spore population was reduced an average of 2.2 to 4.4 log cycles from 105 to 135 C. Heating cycles of 5 and 15 h at temperature were compared with the standard 30-h cycle at 111.7, 120, and 125 C. No significant differences in inactivation (alpha = 0.05) were observed between 111.7 and 120 C. The 30-h cycle differs from the 5- and 15-h cycles at 125 C. Thus, the heating cycle can be reduced if a small fraction (about 0.001 to 0.0001) of very resistant spores can be tolerated.

Puleo, J. R.; Bergstrom, S. L.; Peeler, J. T.; Oxborrow, G. S.

1978-01-01

117

Naturally Occurring Human Urinary Peptides for Use in Diagnosis of Chronic Kidney Disease*  

PubMed Central

Because of its availability, ease of collection, and correlation with physiology and pathology, urine is an attractive source for clinical proteomics/peptidomics. However, the lack of comparable data sets from large cohorts has greatly hindered the development of clinical proteomics. Here, we report the establishment of a reproducible, high resolution method for peptidome analysis of naturally occurring human urinary peptides and proteins, ranging from 800 to 17,000 Da, using samples from 3,600 individuals analyzed by capillary electrophoresis coupled to MS. All processed data were deposited in an Structured Query Language (SQL) database. This database currently contains 5,010 relevant unique urinary peptides that serve as a pool of potential classifiers for diagnosis and monitoring of various diseases. As an example, by using this source of information, we were able to define urinary peptide biomarkers for chronic kidney diseases, allowing diagnosis of these diseases with high accuracy. Application of the chronic kidney disease-specific biomarker set to an independent test cohort in the subsequent replication phase resulted in 85.5% sensitivity and 100% specificity. These results indicate the potential usefulness of capillary electrophoresis coupled to MS for clinical applications in the analysis of naturally occurring urinary peptides. PMID:20616184

Good, David M.; Zurbig, Petra; Argiles, Angel; Bauer, Hartwig W.; Behrens, Georg; Coon, Joshua J.; Dakna, Mohammed; Decramer, Stephane; Delles, Christian; Dominiczak, Anna F.; Ehrich, Jochen H. H.; Eitner, Frank; Fliser, Danilo; Frommberger, Moritz; Ganser, Arnold; Girolami, Mark A.; Golovko, Igor; Gwinner, Wilfried; Haubitz, Marion; Herget-Rosenthal, Stefan; Jankowski, Joachim; Jahn, Holger; Jerums, George; Julian, Bruce A.; Kellmann, Markus; Kliem, Volker; Kolch, Walter; Krolewski, Andrzej S.; Luppi, Mario; Massy, Ziad; Melter, Michael; Neususs, Christian; Novak, Jan; Peter, Karlheinz; Rossing, Kasper; Rupprecht, Harald; Schanstra, Joost P.; Schiffer, Eric; Stolzenburg, Jens-Uwe; Tarnow, Lise; Theodorescu, Dan; Thongboonkerd, Visith; Vanholder, Raymond; Weissinger, Eva M.; Mischak, Harald; Schmitt-Kopplin, Philippe

2010-01-01

118

Natural Ca Isotope Composition of Urine as a Rapid Measure of Bone Mineral Balance  

NASA Astrophysics Data System (ADS)

Naturally occurring stable Ca isotope variations in urine are emerging as a powerful tool to detect changes in bone mineral balance. Bone formation depletes soft tissue of light Ca isotopes while bone resorption releases isotopically light Ca into soft tissue. Previously published work found that variations in Ca isotope composition could be detected at 4 weeks of bed rest in a 90-day bed rest study (data collected at 4, 8 and 12 weeks). A new 30-day bed rest study involved 12 patients on a controlled diet, monitored for 7 days prior to bed rest and 7 days post bed rest. Samples of urine, blood and food were collected throughout the study. Four times daily blood samples and per void urine samples were collected to monitor diurnal or high frequency variations. An improved chemical purification protocol, followed by measurement using multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) allowed accurate and precise determinations of mass-dependent Ca isotope variations in these biological samples to better than 0.2% (?44/42Ca) on <25 ?g of Ca. Results from this new study show that Ca isotope ratios shift in a direction consistent with net bone loss after just 7 days, long before detectible changes in bone density by X-ray measurements occur. Consistent with this interpretation, the Ca isotope variations track changes observed in N-teleopeptide, a bone resorption biomarker. Bone-specific alkaline phosphatase, a bone formation biomarker, is unchanged over this period. Ca isotopes can in principle be used to quantify net changes in bone mass. Using a mass-balance model, our results indicate an average loss of 0.62 0.16 % in bone mass over the course of this 30-day study. This is consistent with the rate of bone loss in longer-term studies as seen by X-ray measurements. This Ca isotope technique should accelerate the pace of discovery of new treatments for bone disease and provide novel insights into the dynamics of bone metabolism.

Skulan, J.; Gordon, G. W.; Morgan, J.; Romaniello, S. J.; Smith, S. M.; Anbar, A. D.

2011-12-01

119

High Diversity of the Fungal Community Structure in Naturally-Occurring Ophiocordyceps sinensis  

PubMed Central

Background Ophiocordyceps sinensis (syn. Cordyceps sinensis), which is a parasite of caterpillars and is endemic to alpine regions on the Tibetan Plateau, is one of the most valuable medicinal fungi in the world. Natural O. sinensis specimens harbor various other fungi. Several of these other fungi that have been isolated from natural O. sinensis specimens have similar chemical components and/or pharmaceutical effects as O. sinensis. Nevertheless, the mycobiota of natural O. sinensis specimens has not been investigated in detail. Methodology/Principal Findings Based on the technique of PCR-single-strand conformation polymorphism (PCR-SSCP), the mycobiota of three different sections (stromata, sclerotia, and mycelial cortices) from natural O. sinensis specimens were investigated using both culture-dependent and -independent methods. For the culture-dependent method, 572 fungal strains were isolated, and 92 putative operational taxonomic units (OTUs) were identified from 226 sequenced strains with the threshold of 97%. For the culture-independent method, 490 fungal clones were identified from about 3000 clones of ITS fragments from the whole-community DNA; based on PCR-SSCP analyses, 266 of these clones were selected to be sequenced, and 118 putative OTUs were detected. The overwhelming majority of isolates/clones and OTUs were detected from mycelial cortices; only a few were detected from stromata and sclerotia. The most common OTUs detected with both methods belonged to Ascomycota; however, only 13 OTUs were detected simultaneously by both methods. Potential novel lineages were detected by each of the two methods. Conclusions/Significance A great number of fungal species present in the mycobiota of naturally-occurring O. sinensis specimens were detected, and many of them may represent undescribed lineages. That only a few of the same OTUs were detected by both methods indicated that different methods should be used. This study increased our understanding about the fungal community structure of this valuable medicinal herb. PMID:21179540

Zhang, Yongjie; Zhang, Shu; Wang, Mu; Bai, Fengyan; Liu, Xingzhong

2010-01-01

120

Arylation of sulfhydryl groups in vitro by the naturally occurring sesquiterpenoid benzoquinone avarone.  

PubMed

Avarone (AQ) is a naturally occurring sesquiterpenoid benzoquinone possessing antileukaemic activity. Its reactivity towards glutathione (GSH) and protein sulfhydryl (SH) groups was investigated. The stoichiometry of AQ reaction with GSH at [GSH]/[AQ] ratios lower than unity proved to be 1:2 (thiol:quinone), consistent with the formation of the corresponding hydroquinone (avarol) as well as a quinone-thioether in the reaction. Conversely, when the [GSH]/[AG] ratio was higher than unity, a hydroquinone-thioether was the only reaction product. AQ/protein interaction was also investigated by using bovine serum albumin (BSA) as model compound. As observed with GSH, arylation rather than oxidation of SH groups appeared to be the mechanism responsible for the AQ-induced depletion of protein SH groups. However, AQ proved to be less effective in depleting BSA sulfhydryls than that of GSH. AQ disappearance after BSA addition was greater than expected on the basis of the total SH groups depleted, if a stoichiometric ratio 1:2 (thiol:quinone) was assumed. It also occurred in the presence of BSA with blocked SH groups, thus suggesting that AQ may react with other nucleophilic protein residues, such as amino or imino groups. When HepG2 cells were exposed to AQ, depletion of both protein SH groups and GSH occurred. However, in contrast to the above, AQ proved to be more effective, probably because of its lipophilic nature, in depleting protein SH groups than GSH. Also, in intact cells AQ appeared to arylate both SH and other nucleophilic groups in proteins. This mechanism may play a major role in AQ-induced cytotoxicity. PMID:8134925

Belisario, M A; Pecce, R; Maturo, M; De Rosa, S

1994-01-26

121

Reactive neurogenesis in response to naturally occurring apoptosis in an adult brain.  

PubMed

Neuronal birth and death are tightly coordinated to establish and maintain properly functioning neural circuits. Disruption of the equilibrium between neuronal birth and death following brain injury or pharmacological insult often induces reactive, and in some cases regenerative, neurogenesis. Many neurodegenerative disorders are not injury-induced, however, so it is critical to determine if and how reactive neurogenesis occurs under noninjury-induced neurodegenerative conditions. Here, we used a model of naturally occurring neural degradation in a neural circuit that controls song behavior in Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii) and examined the temporal dynamics between neuronal birth and death. We found that during seasonal-like regression of the song, control nucleus HVC (proper name), caspase-mediated apoptosis increased within 2 d following transition from breeding to nonbreeding conditions and neural stem-cell proliferation in the nearby ventricular zone (VZ) increased shortly thereafter. We show that inhibiting caspase-mediated apoptosis in HVC decreased neural stem-cell proliferation in the VZ. In baseline conditions the extent of neural stem-cell proliferation correlated positively with the number of dying cells in HVC. We demonstrate that as apoptosis increased and the number of both recently born and pre-existing neurons in HVC decreased, the structure of song, a learned sensorimotor behavior, degraded. Our data illustrate that reactive neurogenesis is not limited to injury-induced neuronal death, but also can result from normally occurring degradation of a telencephalic neural circuit. PMID:25253853

Larson, Tracy A; Thatra, Nivretta M; Lee, Brian H; Brenowitz, Eliot A

2014-09-24

122

Solubilisation of some naturally occurring metal-bearing minerals, limescale and lead phosphate by Aspergillus niger.  

PubMed

The ability of the soil fungus Aspergillus niger to tolerate and solubilise seven naturally occurring metal-bearing minerals, limescale and lead phosphate was investigated. A. niger was able to solubilise four of the test insoluble compounds when incorporated into solid medium: cuprite (CuO2), galena (PbS), rhodochrosite (Mn(CO3)x) and limescale (CaCO3). A. niger was able to grow on all concentrations of all the test compounds, whether solubilisation occurred or not, with no reduction in growth rate from the control. In some cases, stimulation of growth occurred, most marked with the phosphate-containing mineral, apatite. Precipitation of insoluble copper and manganese oxalate crystals under colonies growing on agar amended with cuprite and rhodochrosite was observed after 1-2 days growth at 25 degrees C. This process of oxalate formation represents a reduction in bioavailability of toxic cations, and could represent an important means of toxic metal immobilisation of physiological and environmental significance. PMID:9297818

Sayer, J A; Kierans, M; Gadd, G M

1997-09-01

123

Naturally occurring radionuclides in drinking water: An exercise in risk benefit analysis.  

PubMed

The scientific background information describing the occurrence, measurement, health effects, treatment technology, risk assessment and economic consequences of the presence of naturally occurring radionuclides in drinking water are described for 60,000 public drinking water supplies. The relevant data for the occurrence of radium, uranium and radon in drinking water supplies are discussed and analysed. Radon is of importance because it is released in the process of taking showers and baths and in washing dishes and clothes. Its progeny is then inhaled, leading to the risk of lung cancer. Radium and uranium can both cause bone cancer. The range of average occurrence of natural radioactivity in drinking water is as follows:(226)Ra, 0.3 to 0.8 pCi L(-1);(228)Ra, 0.4 to 1.0 pCi L(-1); uranium, 0.3 to 2.0 pCi L(-1) and(222)Rn, 500 to 600 pCi L(-1). The estimated lifetime risks due to the mean groundwater concentrations of naturally occurring radionuclides are:(226)Ra and(228Ra), 1.0 10(-5); uranium, 2.0 10(-6) and radon, 4.0 10(-4). The cost to reduce total radium levels to 5.0 pCi L(-1) is about $9 million. An equivalent expenditure would be required to reduce radon levels to about 4,000 pCi L(-1), or uranium levels to about 100 pCi L(-1). The problem of maximizing the total mortality and the reduction per unit dollar outlay per unit dollar cost for the uranium/radon case is examined. PMID:24202292

Milvy, P; Cothern, C R

1989-06-01

124

Carbon13 kinetic isotope effects in the decarbonylation of lactic acid of natural isotopic composition in phosphoric acid medium  

Microsoft Academic Search

The13C kinetic isotope effect fractionation in the decarbonylation of lactic acid (LA) of natural isotopic composition by concentrated phosphpric acids (PA) and by 85% H3PO4 has been studied in the temperature interval of 60150C. The values of the13C(1) isotope effects in the decarbonylation of lactic acid in 100% H3PO4, in pyrophosphoric acid and in more concentrated phosphoric acids are intermediate

M. Zieli?ski; G. Czarnota; H. Papiernik-Zieli?ska; G. Kasprzyk; L. Gum?ka; W. Stdter

1993-01-01

125

Background in the context of land contaminated with naturally occurring radioactive material.  

PubMed

The financial implications of choosing a particular threshold for clearance of radioactively contaminated land are substantial, particularly when one considers the volume of naturally occurring radioactive material (NORM) created each year by the production and combustion of fossil fuels and the exploitation of industrial minerals. Inevitably, a compromise needs to be reached between the level of environmental protection sought and the finite resources available for remediation. In the case of natural series radionuclides, any anthropogenic input is always superimposed on the inventory already present in the soil; this 'background' inventory is conventionally disregarded when assessing remediation targets. Unfortunately, the term is not well defined and the concept of 'background dose' is open to alternative interpretations. In this paper, we address the issue of natural background from a geochemical rather than from a solely radiological perspective, illustrating this with an example from the china clay industry. We propose a simple procedure for decision making based on activity concentrations of primordial radionuclides and their progeny. Subsequent calculations of dose need to take into account the mineralogical and chemical characteristics of the contamination, which in the case of NORM are invariably reflected in uranium series disequilibrium. PMID:23519083

Read, D; Read, G D; Thorne, M C

2013-06-01

126

Naturally occurring and experimentally transmitted Hepatozoon americanum in coyotes from Oklahoma.  

PubMed

Twenty free-ranging coyotes (Canis latrans) in Oklahoma (USA) were examined for the presence of naturally occurring infections with Hepatozoon americanum and to determine if bone lesions attributable to H. americanum were present. Although eight of the 20 free-ranging coyotes were found to be naturally infected with H. americanum, no bone lesions were detected. In addition, two coyote pups were exposed to H. americanum oocysts collected from experimentally infected ticks and the course of the resulting infection was followed. Both experimentally infected coyotes developed hepatozoonosis detectable by specific muscle lesions beginning 4 wk after exposure. Bone lesions were detected grossly and histologically at necropsy. Histologic evidence of periosteal bone proliferation ranged from segmental areas of plump hypercellularity and thickening of the periosteum, with minor degrees of osteogenesis, to extensive proliferation of woven bone and periosteal hypercellularity and thickening. Nymphal Amblyomma maculatum that fed on one of the experimentally infected coyote pups became infected and mature H. americanum oocysts were recovered when the ticks molted to adults. These results demonstrate that coyotes in some parts of Oklahoma are naturally infected with H. americanum, that experimentally infected coyotes can develop clinical disease, including characteristic bone lesions, and that A. maculatum nymphs can acquire infections by feeding on them. PMID:10682757

Kocan, A A; Cummings, C A; Panciera, R J; Mathew, J S; Ewing, S A; Barker, R W

2000-01-01

127

ENVIRONMENTAL ISOTOPES FOR RESOLUTION OF HYDROLOGY PROBLEMS  

EPA Science Inventory

The use of environmental isotopes as tracers in the hydrosphere is increasing as analytical instrumentation improves and more applications are discovered. There exists still misconceptions on the role of isotopes in resolving hydrology problems. Naturally occurring isotopes in th...

128

Isotope fractionation by sulfate-reducing natural populations and the isotopic composition of sulfide in marine sediments  

Microsoft Academic Search

Isotope fractionations during sulfate reduction by natural bacterial populations were measured in seven different marine sediments and compared with the isotopic composition of solid-phase sulfides in the same sediments. The measured fractionations during sulfate reduction could explain only between 41% and 85% of the 34S depletion in the sedimentary sulfides. This result directly demonstrates that the depletion of 34S in

Kirsten S. Habicht; Donald E. Canfield

2001-01-01

129

Some Nutritional Characteristics of a Naturally Occurring Alga (Microcystis sp.) in a Guatemalan Lake  

PubMed Central

The nutritional characteristics of an alga (Microcystis sp.) that occurs naturally in a Guatemalan lake were determined. The sun-dried material proved to have a high protein content (55.6%) and to be a possible good source of calcium and phosphorus (1, 169.1 and 633.4 mg/100 mg, respectively). Amino acid analysis showed that total sulfur amino acids were the most deficient ones, giving a protein score of 42 to the material. The in vitro protein digestibility of the material was 69.5%. Biological trials demonstrated that when the material was offered as the only protein source, very low consumption and a high mortality rate were obtained whether or not the diet was supplemented with 0.4% dl-methionine. However, when the material supplied 25% of the total protein of a corn-algae diet, the protein quality of the cereal was significantly improved (P < 0.05). PMID:16345191

de la Fuente, Gabriel; Flores, Antonio; Molina, Mario R.; Almengor, Leticia; Bressani, Ricardo

1977-01-01

130

Hand-held dynamic visual noise reduces naturally occurring food cravings and craving-related consumption.  

PubMed

This study demonstrated the applicability of the well-established laboratory task, dynamic visual noise, as a technique for reducing naturally occurring food cravings and subsequent food intake. Dynamic visual noise was delivered on a hand-held computer device. Its effects were assessed within the context of a diary study. Over a 4-week period, 48 undergraduate women recorded their food cravings and consumption. Following a 2-week baseline, half the participants watched the dynamic visual noise display whenever they experienced a food craving. Compared to a control group, these participants reported less intense cravings. They were also less likely to eat following a craving and consequently consumed fewer total calories following craving. These findings hold promise for curbing unwanted food cravings and craving-driven consumption in real-world settings. PMID:23685086

Kemps, Eva; Tiggemann, Marika

2013-09-01

131

Naturally Occurring Disk Herniation in Dogs: An Opportunity for Pre-Clinical Spinal Cord Injury Research  

PubMed Central

Abstract Traumatic spinal cord injuries represent a significant source of morbidity in humans. Despite decades of research using experimental models of spinal cord injury to identify candidate therapeutics, there has been only limited progress toward translating beneficial findings to human spinal cord injury. Thoracolumbar intervertebral disk herniation is a naturally occurring disease that affects dogs and results in compressive/contusive spinal cord injury. Here we discuss aspects of this disease that are analogous to human spinal cord injury, including injury mechanisms, pathology, and metrics for determining outcomes. We address both the strengths and weaknesses of conducting pre-clinical research in these dogs, and include a review of studies that have utilized these animals to assess efficacy of candidate therapeutics. Finally, we consider a two-species approach to pre-clinical data acquisition, beginning with a reproducible model of spinal cord injury in the rodent as a tool for discovery with validation in pet dogs with intervertebral disk herniation. PMID:21438715

Levine, Gwendolyn J.; Porter, Brian F.; Topp, Kimberly; Noble-Haeusslein, Linda J.

2011-01-01

132

Leishmanicidal and cytotoxic activities of extracts and naturally-occurring compounds from two Lauraceae species.  

PubMed

The in vitro leishmanicidal effects of ethanolic extracts and fifteen naturally-occurring compounds (five lignans, eight neolignans, a diterpene and a dihydrochalcone), obtained from Pleurothyrium cinereum and Ocotea macrophylla, were evaluated on promastigotes of Leishmania panamensis and L. braziliensis. In addition, in order to determine the selective action on Leishmania species as a safety principle, in vitro cytotoxicity on J774 cells was also evaluated for test compounds and extracts. One extract and seven compounds showed activity against Leishmania parasites at different levels. Dihydroflavokawin B (8) was found to be the most potent antileishmanial compound on both parasites, whilst (+)-otobaphenol (14), was found to be the most selective compound on L. panamensis. PMID:21425681

Snchez-Surez, Jeysson; Coy-Barrera, Ericsson; Cuca, Luis Enrique; Delgado, Gabriela

2011-02-01

133

Systems and methods for facilitating hydrogen storage using naturally occurring nanostructure assemblies  

DOEpatents

Some or all of the needs above can be addressed by embodiments of the invention. According to embodiments of the invention, systems and methods for facilitating hydrogen storage using naturally occurring nanostructure assemblies can be implemented. In one embodiment, a method for storing hydrogen can be provided. The method can include providing diatoms comprising diatomaceous earth or diatoms from a predefined culture. In addition, the method can include heating the diatoms in a sealed environment in the presence of at least one of titanium, a transition metal, or a noble metal to provide a porous hydrogen storage medium. Furthermore, the method can include exposing the porous hydrogen storage medium to hydrogen. In addition, the method can include storing at least a portion of the hydrogen in the porous hydrogen storage medium.

Fliermans; , Carl B. (Augusta, GA)

2012-08-07

134

The effect of various naturally occurring metal-binding compounds on the electrochemical behavior of aluminum  

SciTech Connect

Naturally occurring biological molecules are of considerable interest as possible corrosion inhibitors because of increased attention on the development of environmentally compatible, nonpolluting corrosion inhibitors. A hydroxamate yeast siderophore (rhodotorulic acid), a catecholate bacterial siderophore (parabactin), an adhesive protein from the blue mussel Mytilus edulis, and two metal-binding compounds isolated from the tomato and sunflower roots, namely, chlorogenic and caffeic acid, respectively, were adsorbed from solution onto pure aluminum (99.9995%) and their effect on the critical pitting potential and polarization resistance in deaerated 0.1 M NaCl was measured. These measurements were made using anodic polarization and ac impedance spectroscopy. The catechol-containing siderophore has an inhibitive effect on the critical pitting potential of aluminum in 0.1 M NaCl and increases the polarization resistance of the metal over time. The adhesive protein from the blue mussel is also effective in inhibiting the pitting of aluminum.

Hansen, D.C.; McCafferty, E. [Naval Research lab., Washington, DC (United States)

1996-01-01

135

Naturally occurring spore particles at planar fluid interfaces and in emulsions.  

PubMed

We have investigated the potential of utilizing naturally occurring spore particles of Lycopodium clavatum as sole emulsifiers of oil and water mixtures. The preferred emulsions, prepared from either oil-borne or aqueous-borne dispersions of the monodispersed particles of diameter 30 microm, are oil-in-water. The particles act as efficient stabilizers for oils of different polarity. Droplets as large as several millimeters are stable to coalescence indefinitely, despite the low coverage of interfaces by particles observed microscopically. Consistent with the emulsion findings, we discover that particles spontaneously adsorb to bare oil-water interfaces of single drops from oil dispersions, whereas adsorption is less spontaneous and extensive from aqueous dispersions. Monolayers of the spore particles at both air-water and oil-water planar interfaces contain particles in an aggregated state forming clusters and chains. The influence of particle concentration, oil/water ratio, and additives in the aqueous phase is studied. PMID:16114917

Binks, B P; Clint, J H; Mackenzie, G; Simcock, C; Whitby, C P

2005-08-30

136

Review: The history and role of naturally occurring mouse models with Pde6b mutations  

PubMed Central

Mouse models are useful tools for developing potential therapies for human inherited retinal diseases, such as retinitis pigmentosa (RP), since more strains are being identified with the same mutant genes and phenotypes as humans with corresponding retinal degenerative diseases. Mutations in the beta subunit of the human rod phosphodiesterase (PDE6B) gene are a common cause of autosomal recessive RP (arRP). This article focuses on two well-established naturally occurring mouse models of arRP caused by spontaneous mutations in Pde6b, their discovery, phenotype, mechanism of degeneration, strengths and limitations, and therapeutic approaches to restore vision and delay disease progression. Viral vector, especially adeno-associated viral vector (AAV) -mediated gene replacement therapy, pharmacological treatment, cell-based therapy and other approaches that extend the therapeutic window of treatment, is a potentially promising strategy for improving photoreceptor function and significantly slowing the process of retinal degeneration. PMID:24367157

Han, Juanjuan; Dinculescu, Astra; Dai, Xufeng; Du, Wei; Smith, W. Clay

2013-01-01

137

Naturally occurring Parelaphostrongylus tenuis-associated choriomeningitis in a guinea pig with neurologic signs.  

PubMed

An adult male guinea pig (Cavia porcellus) with a 1-month history of hind limb paresis, torticollis, and seizures was euthanized and submitted for necropsy. Gross examination was unremarkable, but histologic examination revealed multifocal eosinophilic and lymphoplasmacytic choriomeningitis and cross sections of nematode parasites within the leptomeninges of the midbrain and diencephalon. Morphologic features of the nematode were consistent with a metastrongyle, and the parasite was identified as Parelaphostrongylus tenuis by polymerase chain reaction testing and nucleotide sequencing. Further questioning of the owner revealed that the guinea pig was fed grass from a yard often grazed by white-tailed deer (Odocoileus virginianus). To the authors' knowledge, this is the first report of a naturally occurring P. tenuis infection in a guinea pig. PMID:23238578

Southard, T; Bender, H; Wade, S E; Grunenwald, C; Gerhold, R W

2013-05-01

138

Variation in daily shedding patterns of Staphylococcus aureus in naturally occurring intramammary infections.  

PubMed

The goal of the current prospective field study was to examine the shedding patterns of naturally occurring Staphylococcus aureus intramammary infections and the association of pulsed field gel electrophoresis pulsotype with shedding. Milk samples from 5 multiparous and 2 primiparous cows identified with S. aureus intramammary infections were collected for 21 consecutive days, 3 times throughout the lactation (63 days total). Cyclicity of each quarter was evaluated using a locally weighted regression. Pulsed field gel electrophoresis was used for genotypic cluster comparisons to evaluate the association of strain type and shedding patterns. Although the amount of shedding varied greatly, 97.5% of the samples were culture positive. There were notable differences in S. aureus shedding patterns among cows as well as within cows; however, no consistent cyclic pattern was identified. Quarters infected with S. aureus isolates grouped in genotypic cluster 1 appeared to shed at consistently higher levels with a median cfu/0.01 ml of 154 (ln[cfu] = 5.0). In comparing ln(cfu)/0.01 ml between genotypic clusters over the first 21-day sample period, accounting for the effect of sample day, samples collected from quarters infected with S. aureus in genotypic cluster 1 had a 1.5 times greater ln(cfu) than those collected from quarters infected with strains in genotypic cluster 2. The ability to detect S. aureus from day to day was very consistent. The current study examining naturally occurring intramammary infections would support the conclusions of other studies suggesting that a single quarter sample would be adequate in determining S. aureus intramammary infections status. PMID:22362791

Walker, Jennifer B; Rajala-Schultz, Pivi J; Walker, William L; Mathews, Jennifer L; Gebreyes, Wondwossen A; DeGraves, Fred J

2011-11-01

139

The effect of inoculum volume on the microbiologic detection of naturally occurring Staphylococcus aureus intramammary infections.  

PubMed

Currently no standard definitions for the diagnosis of Staphylococcus aureus intramammary infection (IMI) exist. As a result, criteria applied in research to diagnose S. aureus IMIs have varied making comparisons between published works difficult. The goal of the current study was to define the optimal inoculum volume used in the diagnosis of naturally occurring S. aureus IMIs. Microbiologic results from 2 field studies examining S. aureus IMIs were used to examine the effects of inoculum volume on the microbiologic detection of S. aureus. A total of 1,583 milk samples were included in the analysis, and the results of using a 0.01-ml and a 0.1-ml inoculum are presented. Using a 0.01-ml inoculum resulted in a sensitivity of 91% (95% confidence interval [CI]: 88.6-93%) and a specificity of 99.4% (95% CI: 98.6-99.8%). Using the larger 0.1-ml inoculum resulted in a sensitivity of 96.8% (95% CI: 95.2-97.9%) and a specificity of 99.3% (95% CI: 98.4-99.7%). All false-positive samples were from S. aureus-negative quarters in S. aureus-positive cows. There were no false-positive cultures from S. aureus-negative cows. Of the false-negative samples, the majority (77%) were from 6 of the 34 S. aureus-positive quarters. Results from the current study of naturally occurring S. aureus IMIs support the hypothesis that, when using quarter level milk samples, a S. aureus IMI is most accurately diagnosed using a 0.1-ml inoculum. Regardless of inoculum volume, a single quarter sample culture that is positive with S. aureus (>or=1 colony-forming unit) is sufficient to diagnose a S. aureus IMI. PMID:20807927

Walker, Jennifer B; Rajala-Schultz, Pivi J; DeGraves, Fred J

2010-09-01

140

Naturally Occurring Eccentric Cleavage Products of Provitamin A ?-Carotene Function as Antagonists of Retinoic Acid Receptors*  

PubMed Central

?-Carotene is the major dietary source of provitamin A. Central cleavage of ?-carotene catalyzed by ?-carotene oxygenase 1 yields two molecules of retinaldehyde. Subsequent oxidation produces all-trans-retinoic acid (ATRA), which functions as a ligand for a family of nuclear transcription factors, the retinoic acid receptors (RARs). Eccentric cleavage of ?-carotene at non-central double bonds is catalyzed by other enzymes and can also occur non-enzymatically. The products of these reactions are ?-apocarotenals and ?-apocarotenones, whose biological functions in mammals are unknown. We used reporter gene assays to show that none of the ?-apocarotenoids significantly activated RARs. Importantly, however, ?-apo-14?-carotenal, ?-apo-14?-carotenoic acid, and ?-apo-13-carotenone antagonized ATRA-induced transactivation of RARs. Competitive radioligand binding assays demonstrated that these putative RAR antagonists compete directly with retinoic acid for high affinity binding to purified receptors. Molecular modeling studies confirmed that ?-apo-13-carotenone can interact directly with the ligand binding site of the retinoid receptors. ?-Apo-13-carotenone and the ?-apo-14?-carotenoids inhibited ATRA-induced expression of retinoid responsive genes in Hep G2 cells. Finally, we developed an LC/MS method and found 35 nm ?-apo-13-carotenone was present in human plasma. These findings suggest that ?-apocarotenoids function as naturally occurring retinoid antagonists. The antagonism of retinoid signaling by these metabolites may have implications for the activities of dietary ?-carotene as a provitamin A and as a modulator of risk for cardiovascular disease and cancer. PMID:22418437

Eroglu, Abdulkerim; Hruszkewycz, Damian P.; dela Sena, Carlo; Narayanasamy, Sureshbabu; Riedl, Ken M.; Kopec, Rachel E.; Schwartz, Steven J.; Curley, Robert W.; Harrison, Earl H.

2012-01-01

141

P-Element repression in Drosophila melanogaster by a naturally occurring defective telomeric P copy.  

PubMed Central

In Drosophila melanogaster, hybrid dysgenesis occurs in progeny from crosses between females lacking P elements and males carrying P elements scattered throughout the genome. We have genetically isolated a naturally occurring P insertion at cytological location 1A, from a Tunisian population. The Nasr'Allah-P(1A) element [NA-P(1A)] has a deletion of the first 871 bp including the P promoter. It is flanked at the 3' end by telomeric associated sequences and at the 5' end by a HeT-A element sequence. The NA-P(1A) element strongly represses dysgenic sterility and P transposition. However, when testing P-promoter repression, NA-P(1A) was unable to repress a germinally expressed P-lacZ construct bearing no 5'-homology with it. Conversely, a second P-lacZ construct, in which the fusion with lacZ takes place in exon 3 of P, was successfully repressed by NA-P(1A). This suggests that NA-P(1A) repression involves a homology-dependent component. PMID:10924479

Marin, L; Lehmann, M; Nouaud, D; Izaabel, H; Anxolabehere, D; Ronsseray, S

2000-01-01

142

Identification of naturally occurring hybrids between two overexploited sciaenid species along the South African coast.  

PubMed

Hybridisation between fish species can play a significant role in evolutionary processes and can influence management and conservation planning, however, this phenomenon has been widely understudied, especially in marine organisms. The distribution limits of two sciaenid species (silver kob, Argyrosomus inodorus, and dusky kob, A. japonicus) partly overlap along the South African coast, where both species have undergone severe depletion due to overfishing. Following the identification of a number of possible cases of species misidentification or hybridisation (21 out of 422 individuals), nuclear and mitochondrial DNA data (12microsatellite loci and 562bp of the COI gene) were analysed to investigate the genetic composition of these individuals. Results indicated a field-based species misidentification rate of approximately 2.8% and a rate of natural hybridisation of 0.7%. Interestingly, all hybrid fish resulted from first-generation (F1) hybridisation events, which occurred exclusively between silver kob females and dusky kob males. Whether hybridisation is the result of natural events (such as secondary contact following a shift in distribution range), or anthropogenic activities (size-selective pressure due to overfishing), these findings have important implications for critical recovery and future management of these species in the wild. PMID:24582737

Mirimin, L; Kerwath, S E; Macey, B M; Bester-van der Merwe, A E; Lamberth, S J; Bloomer, P; Roodt-Wilding, R

2014-07-01

143

Measurement of lithium isotope ratios by quadrupole-ICP-MS: application to seawater and natural carbonates  

E-print Network

­7,9,10 The two stable isotopes of lithium (6 Li and 7 Li) have a large mass difference ($16%), resulting and analysis. Our interest in lithium isotope analyses stems from the crea- tion of d7 Li and Li/Ca recordMeasurement of lithium isotope ratios by quadrupole-ICP-MS: application to seawater and natural

Weston, Ken

144

Survey of Natural Cadmium Isotope Fractionation by Double Spike Thermal Ionisation Mass Spectrometry  

Microsoft Academic Search

Wombacher et al. (2003) have shown recently that natural Cd isotope fractionations in terrestrial materials are extremely limited (~100 ppm\\/amu or less). Thus, excellent external precision is absolutely paramount if Cd isotope fractionations are to be adequately quantified. Here we present a new high-precision double spike (DS) technique for Cd isotopes in which the Cd is measured by thermal ionisation

A. Schmitt; S. J. Galer; W. Abouchami

2006-01-01

145

Lead isotopes in sediments of the Loire River (France): natural versus anthropogenic origin  

E-print Network

Lead isotopes in sediments of the Loire River (France): natural versus anthropogenic origin France) were investigated by means of lead isotopes determined on the labile sediment fraction, or acid-extractable matter (AEM). The combination of trace elements and lead isotopes allows deciphering the origin

Paris-Sud XI, Université de

146

Naturally Occurring Variants of Human ?9 Nicotinic Receptor Differentially Affect Bronchial Cell Proliferation and Transformation  

PubMed Central

Isolation of polyadenilated mRNA from human immortalized bronchial epithelial cell line BEP2D revealed the presence of multiple isoforms of RNA coded by the CHRNA9 gene for ?9 nicotinic acetylcholine receptor (nAChR). BEP2D cells were homozygous for the rs10009228 polymorphism encoding for N442S amino acid substitution, and also contained mRNA coding for several truncated isoforms of ?9 protein. To elucidate the biologic significance of the naturally occurring variants of ?9 nAChR, we compared the biologic effects of overexpression of full-length ?9 N442 and S442 proteins, and the truncated ?9 variant occurring due to a loss of the exon 4 sequence that causes frame shift and early termination of the translation. These as well as control vector were overexpressed in the BEP2D cells that were used in the assays of proliferation rate, spontaneous vs. tobacco nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced cellular transformation, and tumorigenicity in cell culture and mice. Overexpression of the S442 variant significantly increased cellular proliferation, and spontaneous and NNK-induced transformation. The N442 variant significantly decreased cellular transformation, without affecting proliferation rate. Overexpression of the truncated ?9 significantly decreased proliferation and suppressed cellular transformation. These results suggested that ?9 nAChR plays important roles in regulation of bronchial cell growth by endogenous acetylcholine and exogenous nicotine, and susceptibility to NNK-induced carcinogenic transformation. The biologic activities of ?9 nAChR may be regulated at the splicing level, and genetic polymorphisms in CHRNA9 affecting protein levels, amino acid sequence and RNA splicing may influence the risk for lung cancer. PMID:22125646

Chikova, Anna; Grando, Sergei A.

2011-01-01

147

Effects of naturally occurring coumarins on hepatic drug-metabolizing enzymes inmice  

SciTech Connect

Cytochromes P450 (P450s) and glutathione S-transferases (GSTs) constitute two important enzyme families involved in carcinogen metabolism. Generally, P450s play activation or detoxifying roles while GSTs act primarily as detoxifying enzymes. We previously demonstrated that oral administration of the linear furanocoumarins, isopimpinellin and imperatorin, modulated P450 and GST activities in various tissues of mice. The purpose of the present study was to compare a broader range of naturally occurring coumarins (simple coumarins, and furanocoumarins of the linear and angular type) for their abilities to modulate hepatic drug-metabolizing enzymes when administered orally to mice. We now report that all of the different coumarins tested (coumarin, limettin, auraptene, angelicin, bergamottin, imperatorin and isopimpinellin) induced hepatic GST activities, whereas the linear furanocoumarins possessed the greatest abilities to induce hepatic P450 activities, in particular P450 2B and 3A. In both cases, this corresponded to an increase in protein expression of the enzymes. Induction of P4502B10, 3A11, and 2C9 by xenobiotics often is a result of activation of the pregnane X receptor (PXR) and/or constitutive androstane receptor (CAR). Using a pregnane X receptor reporter system, our results demonstrated that isopimpinellin activated both PXR and its human ortholog SXR by recruiting coactivator SRC-1 in transfected cells. In CAR transfection assays, isopimpinellin counteracted the inhibitory effect of androstanol on full-length mCAR, a Gal4-mCAR ligand-binding domain fusion, and restored coactivator binding. Orally administered isopimpinellin induced hepatic mRNA expression of Cyp2b10, Cyp3a11, and GSTa in CAR(+/+) wild-type mice. In contrast, the induction of Cyp2b10 mRNA by isopimpinellin was attenuated in the CAR(-/-) mice, suggesting that isopimpinellin induces Cyp2b10 via the CAR receptor. Overall, the current data indicate that naturally occurring coumarins have diverse activities in terms of inducing various xenobiotic metabolizing enzymes based on their chemical structure.

Kleiner, Heather E. [Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Park Road 1-C, Smithville, TX 78957 (United States)], E-mail: hklein@lsuhsc.edu; Xia, Xiaojun; Sonoda, Junichiro [Howard Hughes Medical Institute, Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA 92037 (United States); Zhang, Jun [Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 (United States); Pontius, Elizabeth; Abey, Jane [Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Park Road 1-C, Smithville, TX 78957 (United States); Evans, Ronald M. [Howard Hughes Medical Institute, Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA 92037 (United States); Moore, David D. [Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 (United States); DiGiovanni, John [Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Park Road 1-C, Smithville, TX 78957 (United States)

2008-10-15

148

Effects of Naturally Occurring Coumarins on Hepatic Drug Metabolizing Enzymes in Mice  

PubMed Central

Cytochromes P450 (P450s) and glutathione S-transferases (GSTs) constitute two important enzyme families involved in carcinogen metabolism. Generally, P450s play activation or detoxifying roles while GSTs act primarily as detoxifying enzymes. We previously demonstrated that oral administration of the linear furanocoumarins, isopimpinellin and imperatorin, modulated P450 and GST activities in various tissues of mice. The purpose of the present study was to compare a broader range of naturally occurring coumarins (simple coumarins, and furanocoumarins of the linear and angular type) for their abilities to modulate hepatic drug metabolizing enzymes when administered orally to mice. We now report that all of the different coumarins tested (coumarin, limettin, auraptene, angelicin, bergamottin, imperatorin and isopimpinellin) induced hepatic GST activities, whereas the linear furanocoumarins possessed the greatest abilities to induce hepatic P450 activities, in particular P450 2B and 3A. In both cases, this corresponded to an increase in protein expression of the enzymes. Induction of P4502B10, 3A11, and 2C9 by xenobiotics often are a result of activation of the pregnane X receptor (PXR) and/or constitutive androstane receptor (CAR). Using a pregnane X receptor reporter system, our results demonstrated that isopimpinellin activated both PXR and its human ortholog SXR by recruiting coactivator SRC-1 in transfected cells. In CAR transfection assays, isopimpinellin counteracted the inhibitory effect of androstanol on full length mCAR, a Gal4-mCAR ligand binding domain fusion, and restored coactivator binding. Orally administered isopimpinellin induced hepatic mRNA expression of Cyp2b10,Cyp3a1, GSTa in CAR(+/+) wild-type mice. In contrast, the induction of Cyp2b10 mRNA by isopimpinellin was attenuated in the CAR(?/?) mice, suggesting that isopimpinellin induces Cyp2b10 via the CAR receptor. Overall, the current data indicate that naturally occurring coumarins have diverse activities in terms of inducing various xenobiotic metabolizing enzymes based on their chemical structure. PMID:18692084

Kleiner, Heather E.; Xia, Xiojun; Sonoda, Junichiro; Zhang, Jun; Pontius, Elizabeth; Abey, Jane; Evans, Ronald M.; Moore, David D.; DiGiovanni., John

2008-01-01

149

Molecular characterization of a naturally occurring intraspecific recombinant begomovirus with close relatives widespread in southern Arabia  

PubMed Central

Background Tomato leaf curl Sudan virus (ToLCSDV) is a single-stranded DNA begomovirus of tomato that causes downward leaf curl, yellowing, and stunting. Leaf curl disease results in significant yield reduction in tomato crops in the Nile Basin. ToLCSDV symptoms resemble those caused by Tomato yellow leaf curl virus, a distinct and widespread begomovirus originating in the Middle East. In this study, tomato samples exhibiting leaf curl symptoms were collected from Gezira, Sudan. The associated viral genome was molecularly characterized, analyzed phylogenetically, and an infectious clone for one isolate was constructed. Findings The complete genomes for five newly discovered variants of ToLCSDV, ranging in size from 2765 to 2767-bp, were cloned and sequenced, and subjected to pairwise and phylogenetic analyses. Pairwise analysis indicated that the five Gezira isolates shared 97-100% nucleotide identity with each other. Further, these variants of ToLCSDV shared their highest nucleotide identity at 96-98%, 91-95%, 91-92%, and 91-92% with the Shambat, Gezira, Oman and Yemen strains of ToLCSDV, respectively. Based on the high maximum nucleotide identities shared between these ToLCSDV variants from Gezira and other previously recognized members of this taxonomic group, they are considered isolates of the Shambat strain of ToLCSDV. Analysis of the complete genome sequence for these new variants revealed that they were naturally occurring recombinants between two previously reported strains of ToLCSDV. Finally, a dimeric clone constructed from one representative ToLCSV genome from Gezira was shown to be infectious following inoculation to tomato and N. benthamiana plants. Conclusion Five new, naturally occurring recombinant begomovirus variants (>96% shared nt identity) were identified in tomato plants from Gezira in Sudan, and shown to be isolates of the Shambat strain of ToLCSDV. The cloned viral genome was infectious in N. benthamiana and tomato plants, and symptoms in tomato closely resembled those observed in field infected tomato plants, indicating the virus is the causal agent of the leaf curl disease. The symptoms that developed in tomato seedlings closely resembled those observed in field infected tomato plants, indicating that ToLCSDV is the causal agent of the leaf curl disease in Gezira. PMID:24890736

2014-01-01

150

Spectral Analysis of Naturally Occurring Methylxanthines (Theophylline, Theobromine and Caffeine) Binding with DNA  

PubMed Central

Nucleic acids exist in a dynamic equilibrium with a number of molecules that constantly interact with them and regulate the cellular activities. The inherent nature of the structure and conformational integrity of these macromolecules can lead to altered biological activity through proper targeting of nucleic acids binding ligands or drug molecules. We studied the interaction of naturally occurring methylxanthines such as theophylline, theobromine and caffeine with DNA, using UV absorption and Fourier transform infrared (FTIR) spectroscopic methods, and especially monitored their binding affinity in the presence of Mg2+ and during helix-coil transitions of DNA by temperature (Tm) or pH melting profiles. The study indicates that all these molecules effectively bind to DNA in a dose dependent manner. The overall binding constants of DNA-theophylline?=?3.5103 M?1, DNA-theobromine?=?1.1103 M?1, and DNA-Caffeine?=?3.8103 M?1. On the other hand Tm/pH melting profiles showed 2435% of enhanced binding activity of methylxanthines during helix-coil transitions of DNA rather than to its native double helical structure. The FTIR analysis divulged that theophylline, theobromine and caffeine interact with all the base pairs of DNA (A-T; G-C) and phosphate group through hydrogen bond (H-bond) interaction. In the presence of Mg2+, methylxanthines altered the structure of DNA from B to A-family. However, the B-family structure of DNA remained unaltered in DNA-methylxanthines complexes or in the absence of Mg2+. The spectral analyses indicated the order of binding affinity as caffeine?theophylline>theobromine to the native double helical DNA, and theophylline?theobromine>caffeine to the denatured form of DNA and in the presence of divalent metal ions. PMID:23236361

Johnson, Irudayam Maria; Prakash, Halan; Prathiba, Jeyaguru; Raghunathan, Raghavachary; Malathi, Raghunathan

2012-01-01

151

Spectral analysis of naturally occurring methylxanthines (theophylline, theobromine and caffeine) binding with DNA.  

PubMed

Nucleic acids exist in a dynamic equilibrium with a number of molecules that constantly interact with them and regulate the cellular activities. The inherent nature of the structure and conformational integrity of these macromolecules can lead to altered biological activity through proper targeting of nucleic acids binding ligands or drug molecules. We studied the interaction of naturally occurring methylxanthines such as theophylline, theobromine and caffeine with DNA, using UV absorption and Fourier transform infrared (FTIR) spectroscopic methods, and especially monitored their binding affinity in the presence of Mg(2+) and during helix-coil transitions of DNA by temperature (T(m)) or pH melting profiles. The study indicates that all these molecules effectively bind to DNA in a dose dependent manner. The overall binding constants of DNA-theophylline?=?3.510(3) M(-1), DNA-theobromine?=?1.110(3) M(-1), and DNA-Caffeine?=?3.810(3) M(-1). On the other hand T(m)/pH melting profiles showed 24-35% of enhanced binding activity of methylxanthines during helix-coil transitions of DNA rather than to its native double helical structure. The FTIR analysis divulged that theophylline, theobromine and caffeine interact with all the base pairs of DNA (A-T; G-C) and phosphate group through hydrogen bond (H-bond) interaction. In the presence of Mg(2+), methylxanthines altered the structure of DNA from B to A-family. However, the B-family structure of DNA remained unaltered in DNA-methylxanthines complexes or in the absence of Mg(2+). The spectral analyses indicated the order of binding affinity as "caffeine?theophylline>theobromine" to the native double helical DNA, and "theophylline?theobromine>caffeine to the denatured form of DNA and in the presence of divalent metal ions. PMID:23236361

Johnson, Irudayam Maria; Prakash, Halan; Prathiba, Jeyaguru; Raghunathan, Raghavachary; Malathi, Raghunathan

2012-01-01

152

Potential environmental and regulatory implications of naturally occurring radioactive materials (NORM).  

PubMed

The immense volume of naturally occurring radioactive materials (NORM) wastes produced annually by extracting industries throughout the world deserves to come to the attention of international and national environmental protection agencies and regulatory bodies. Although a great deal of work has been done in the fields of radiation protection and remedial actions concerning uranium and other mines, the need to dispose of diffuse NORM wastes will have environmental and regulatory implications that thus far are not fully appreciated. NORM wastes constitute, by and large, unwanted byproducts of industrial activities as diverse as thorium and uranium milling, niobium, tin and gold mining extraction, water treatment, and the production of oil, gas, phosphate fertilizer, coal fire and aluminum. The volumes of NORM wastes produced annually could reach levels so high that the existing low level radioactive waste (LLRW) facilities would be readily occupied by NORM if controlled disposal procedures were not adopted. On the other hand, NORM cannot just be ignored as being below radiological concern (BRC) or lower than exempt concentration levels (ECLs), because sometimes NORM concentrations reach levels as high as 1 x 10(3) kBq/kg for 226Ra, and not much less for 228Ra. Unfortunately, thus far there is not enough information available concerning NORM wastes in key industries, though the international scientific community has been concerned, for a long time now, with technologically enhanced natural radiation exposures (TENRE). This article is written with the intention of examining, to the extent possible, the potential environmental and regulatory implications of NORM wastes being produced in selected industries. PMID:9451772

Paschoa, A S

1998-03-01

153

Radiological impact of dietary intakes of naturally occurring radionuclides on Pakistani adults.  

PubMed

Daily dietary intakes of three naturally occurring long-lived radionuclides (232)Th, (238)U and (40)K were estimated for the adult population of Pakistan using neutron activation analysis (NAA), inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS), respectively. The daily intakes of (232)Th ranged from 4 to 29 mBq, (238)U ranged from 17 to 82 mBq and (40)K ranged from 51 to 128 Bq. The geometric means of these intakes were 10 mBqd(-1) for (232)Th, 33 mBqd(-1) for (238)U and 78.5 Bqd(-1) for (40)K. The measured values give annual committed effective doses of 0.80, 0.53 and 178.75 microSvyr(-1) for (232)Th, (238)U and (40)K, respectively to Pakistani population. The net radiological impact of these radionuclides is 180.08 microSvyr(-1). This value gives cancer risk factor of 4.5 x 10(-4) and loss of life expectancy of 0.87 days only. Whereas ICRP cancer risk factor for general public is 2.5 x 10(-3) and total risk involve from the all natural radiation sources based on global average annual radiation dose of 2.4 mSvyr(-1) is 6.0 x 10(-3). The estimated cancer risk shows that probability of increase of cancer risk from daily Pakistani diet is only a minor fraction of ICRP values. Therefore, the diet does not pose any significant health hazard and is considered radiologically safe for human consumption. PMID:17034921

Akhter, P; Rahman, K; Orfi, S D; Ahmad, N

2007-02-01

154

Natural thorium isotopes in marine sediment core off Labuan port  

NASA Astrophysics Data System (ADS)

Sediment core was collected from Labuan port and analyzed to determine the radioactivity of thorium (Th) isotopes. The objectives of this study are to determine the possible sources of Th isotopes at Labuan port and estimates the sedimentation rate based on 228Th/232Th model. The results suggest the 230Th and 232Th might be originated from terrestrial sedimentary rock while 228Th originated by authigenic origin. High ratio value of 230Th/232Th detected at the top surface sediment indicates the increasing of 230Th at the recent years which might be contributed from the anthropogenic sources. The sedimentation rate of core sediment from Labuan Port was successfully estimated by using 228Th/232Th model. The result show high sedimentation rate with 4.67 cm/year indicates rapid deposition occurred at this study area due to the high physical activity at the Labuan port. By assume the constant sedimentation rate at this area; we estimated the age of 142 cm core sediment obtained from Labuan port is 32 years started from 1981 to 2012. This chronology will be used in forthcoming research to investigate the historical profile of anthropogenic activities affecting the Labuan port.

Hafidz, B. Y.; Asnor, A. S.; Terence, R. C.; Mohamed, C. A. R.

2014-02-01

155

The impact of a Naturally Occurring Retirement Communities service program in Maryland, USA.  

PubMed

Most older adults prefer to age in place and it is therefore vital to support them in maintaining a high quality of life in their place of residence. Many Naturally Occurring Retirement Communities (NORCs) have implemented services to fulfill a range of needs of their residents. Community Partners (CP) provided 58 NORC residents in six apartment buildings within two suburban neighborhoods in Maryland with health and social work services, activities and transportation services. Participants were compared with 70 residents who did not receive these services. Residents were assessed prior to initiation of services (e.g. transportation, social work and recreation) and after service usage through a membership program. Members had significantly increased satisfaction with recreational activities and social life in the community as well as significant decreases in depressed affect. Members' self-reports showed that they were more likely to get out of the house, felt less isolated, and were happier since joining CP activities. This study is unique in examining the impact of utilization of a variety of services for older persons, while comparing these individuals to a local group of community-dwelling older persons who are without NORC services. PMID:20200021

Cohen-Mansfield, Jiska; Dakheel-Ali, Maha; Frank, Julia K

2010-06-01

156

Repair of naturally occurring mismatches can induce mutations in flanking DNA  

PubMed Central

Normal genomic DNA contains hundreds of mismatches that are generated daily by the spontaneous deamination of C (U/G) and methyl-C (T/G). Thus, a mutagenic effect of their repair could constitute a serious genetic burden. We show here that while mismatches introduced into human cells on an SV40-based episome were invariably repaired, this process induced mutations in flanking DNA at a significantly higher rate than no mismatch controls. Most mutations involved the C of TpC, the substrate of some single strand-specific APOBEC cytidine deaminases, similar to the mutations that can typify the mutator phenotype of numerous tumors. siRNA knockdowns and chromatin immunoprecipitation showed that TpC preferring APOBECs mediate the mutagenesis, and siRNA knockdowns showed that both the base excision and mismatch repair pathways are involved. That naturally occurring mispairs can be converted to mutators, represents an heretofore unsuspected source of genetic changes that could underlie disease, aging, and evolutionary change. DOI: http://dx.doi.org/10.7554/eLife.02001.001 PMID:24843013

Chen, Jia; Miller, Brendan F; Furano, Anthony V

2014-01-01

157

Naturally occurring Mycoplasma bovis-associated pneumonia and polyarthritis in feedlot beef calves.  

PubMed

Mycoplasma bovis is perceived as an emerging cause of mortality in feedlot beef cattle. This study examined the lesions and infectious agents in naturally occurring M. bovis-associated bronchopneumonia and arthritis and the relationship of this condition with bovine viral diarrhea virus (BVDV) infection. Standardized pathologic, immunohistochemical, and microbiologic investigations were conducted on 99 calves that died or were euthanized within 60 days after arrival in 72 feedlots. Cranioventral bronchopneumonia with multiple foci of caseous necrosis was identified in 54 of 99 calves, including 30 with concurrent fibrinosuppurative bronchopneumonia typical of pneumonic pasteurellosis. Mycoplasma bovis was consistently identified in these lesions by culture and immunohistochemistry, but also commonly in healthy lungs and those with pneumonia of other causes. Focal lesions of coagulation necrosis, typical of pneumonic pasteurellosis, were often infected with both Mannheimia haemolytica and M. bovis. Arthritis was present in 25 of 54 (46%) calves with M. bovis pneumonia, and all calves with arthritis had pneumonia. BVDV infection was more common in calves with lesions of bacterial pneumonia than in those dying of other causes, but BVDV infection was not more common in calves with caseonecrotic bronchopneumonia than those with fibrinosuppurative bronchopneumonia. Retrospective analysis identified cases of M. bovis pneumonia in the early 1980s that had milder lesions than the current cases. The findings suggest that, in at least some calves, M. bovis induces caseonecrotic bronchopneumonia within the lesions of pneumonic pasteurellosis. PMID:16566255

Gagea, Mihai I; Bateman, Kenneth G; Shanahan, Rachel A; van Dreumel, Tony; McEwen, Beverly J; Carman, Susy; Archambault, Marie; Caswell, Jeff L

2006-01-01

158

Use of naturally occurring mercury to determine the importance of cutthroat trout to Yellowstone grizzly bears  

USGS Publications Warehouse

Spawning cutthroat trout (Oncorhynchus clarki (Richardson, 1836)) are a potentially important food resource for grizzly bears (Ursus arctos horribilis Ord, 1815) in the Greater Yellowstone Ecosystem. We developed a method to estimate the amount of cutthroat trout ingested by grizzly bears living in the Yellowstone Lake area. The method utilized (i) the relatively high, naturally occurring concentration of mercury in Yellowstone Lake cutthroat trout (508 ?? 93 ppb) and its virtual absence in all other bear foods (???6 ppb), (ii) hair snares to remotely collect hair from bears visiting spawning cutthroat trout streams between 1997 and 2000, (iii) DNA analyses to identify the individual and sex of grizzly bears leaving a hair sample, (iv) feeding trials with captive bears to develop relationships between fish and mercury intake and hair mercury concentrations, and (v) mercury analyses of hair collected from wild bears to estimate the amount of trout consumed by each bear. Male grizzly bears consumed an average of 5 times more trout/kg bear than did female grizzly bears. Estimated cutthroat trout intake per year by the grizzly bear population was only a small fraction of that estimated by previous investigators, and males consumed 92% of all trout ingested by grizzly bears.

Felicetti, L.A.; Schwartz, C.C.; Rye, R.O.; Gunther, K.A.; Crock, J.G.; Haroldson, M.A.; Waits, L.; Robbins, C.T.

2004-01-01

159

Antioxidant effect of naturally occurring xanthines on the oxidative damage of DNA bases  

NASA Astrophysics Data System (ADS)

The repair of the oxidised radicals of adenine and guanosine by several naturally occurring xanthines was studied. Each pair of DNA purine/xanthine was made to react with the sulphate radical and the decrease of the concentration of both compounds was measured by HPLC as a function of irradiation time. The results show that xanthine efficiently prevents the oxidation of the two DNA purines. Theophyline and paraxanthine repair the oxidised radical of adenine but not the one from guanosine. Theobromine and caffeine do not show any protecting effect. An order of the oxidation potentials of all the purines studied is proposed. La rparation des radicaux oxyds de l'adnine et de la guanosine par des xanthines naturelles a t tudie en soumettant chaque paire base de l'ADN/xanthine l'oxydation par le radical sulfate et en mesurant par HPLC la disparition des deux composs en fonction du temps d'irradiation. Les rsultats montrent que la xanthine joue un rle protecteur efficace contre l'oxydation des deux purines de l'ADN. La thophyline et la paraxanthine rparent le radical oxyd de l'adnine mais pas celui de la guanosine. La thobromine et la cafene n'ont pas d'effet protecteur. Un ordre de potentiels d'oxydation des purines tudies est propos.

Vieira, A. J. S. C.; Telo, J. P.; Pereira, H. F.; Patrocnio, P. F.; Dias, R. M. B.

1999-01-01

160

Treatment of Obesity-Related Complications with Novel Classes of Naturally Occurring PPAR Agonists  

PubMed Central

The prevalence of obesity and its associated comorbidities has grown to epidemic proportions in the US and worldwide. Thus, developing safe and effective therapeutic approaches against these widespread and debilitating diseases is important and timely. Activation of peroxisome proliferator-activated receptors (PPARs) ?, ?, and ? through several classes of pharmaceuticals can prevent or treat a variety of metabolic and inflammatory diseases, including type II diabetes (T2D). Thus, PPARs represent important molecular targets for developing novel and better treatments for a wide range of debilitating and widespread obesity-related diseases and disorders. However, available PPAR ? agonistic drugs such as Avandia have significant adverse side effects, including weight gain, fluid retention, hepatotoxicity, and congestive heart failure. An alternative to synthetic agonists of PPAR ? is the discovery and development of naturally occurring and safer nutraceuticals that may be dual or pan PPAR agonists. The purpose of this paper is to summarize the health effects of three plant-derived PPAR agonists: abscisic acid (ABA), punicic acid (PUA), and catalpic acid (CAA) in the prevention and treatment of chronic inflammatory and metabolic diseases and disorders. PMID:21253508

Bassaganya-Riera, Josep; Guri, Amir J.; Hontecillas, Raquel

2011-01-01

161

SUPPLEMENTARY COMPARISON Technically enhanced naturally occurring radionuclides (TENORM) in phosphogypsum: Comparison CCRI(II)-S5  

NASA Astrophysics Data System (ADS)

Within the frame of mutual cooperation between the IAEA and the BIPM, the Consultative Committee for Ionizing Radiation Section IIMeasurement of Radionuclides accepted an IAEA-organized interlaboratory comparison in 2008 on the determination of technically enhanced naturally occurring radionuclides in phosphogypsum. The study was piloted by the Chemistry Unit at the IAEA's Laboratories in Seibersdorf (Austria). This report presents the methodology applied in conducting this comparison and the results. Activity results for Pb-210, Ra-226, Th-230, U-234, U-235 and U-238 were reported by three national metrology institutes (NMI) and five other expert laboratories or designated institutes. Four different approaches were used to calculate the nominal value of the reported results and associated uncertainties, and the results from each individual participant were evaluated and compared with this nominal reference value. The reported evaluation of the measurement results demonstrated agreement amongst the participating laboratories. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Shakhashiro, A.; Sansone, U.; Wershofen, H.; Bollhfer, A.; Kim, C. K.; Kim, C. S.; Korun, M.; Moune, M.; Lee, S. H.; Tarjan, S.

2010-01-01

162

Relationships of phytomacrofauna to surface area in naturally occurring macrophyte stands  

USGS Publications Warehouse

Most studies of the relationships between freshwater macrophytes and phytomacrofauna, or the macroinvertebrates associated with the macrophytes, have been based on individual plant collections or samples from monotypic plant stands. We describe the phytomacrofauna assemblages within naturally occurring, taxonomically mixed stands, and consider how macrophyte surface area and plant morphology influenced phytomacrofauna diversity and abundance. Samples of submersed macrophytes and phytomacrofauna were collected April-November 1979 in Anchor Bay of Lake St. Clair. Only the portions of macrophytes within the water column and invertebrates from above the sediment were considered. Densities of phytomacrofauna were not consistently related to fluctuations in macrophyte surface area, indicating that the use of macrophyte structure by the invertebrates changed during the year. Both the abundance and species richness of the phytomacrofauna were strongly related to macrophyte species richness reflecting the response of the invertebrates to the structural heterogeneity in taxonomically mixed stands. Vertically heterogeneous stands with an understory of Chara and an overstory of vascular macrophytes, for example, were likely to contain more invertebrates than stands with only one macrophyte taxon.

Brown, Charles L.; Poe, Thomas P.; French, John R. P., III; Schloesser, Donald W.

1988-01-01

163

Naturally occurring HCA1 missense mutations result in loss of function: potential impact on lipid deposition.  

PubMed

The hydroxy-carboxylic acid receptor (HCA1) is a G protein-coupled receptor that is highly expressed on adipocytes and considered a potential target for the treatment of dyslipidemia. In the current study, we investigated the pharmacological properties of naturally occurring variants in this receptor (H43Q, A110V, S172L, and D253H). After transient expression of these receptors into human embryonic kidney 293 cells, basal and ligand-induced signaling were assessed using luciferase reporter gene assays. The A110V, S172L, and D253 variants showed reduced basal activity; the S172L mutant displayed a decrease in potency to the endogenous ligand L-lactate. Both the S172L and D253H variants also showed impaired cell surface expression, which may in part explain the reduced activity of these receptors. The impact of a loss in HCA1 function on lipid accumulation was investigated in the adipocyte cell line, OP9. In these cells, endogenous HCA1 transcript levels rapidly increased and reached maximal levels 3 days after the addition of differentiation media. Knockdown of HCA1 using siRNA resulted in an increase in lipid accumulation as assessed by quantification of Nile Red staining and TLC analysis. Our data suggest that lipid homeostasis may be altered in carriers of selected HCA1 missense variants. PMID:23268337

Doyle, Jamie R; Lane, Jacqueline M; Beinborn, Martin; Kopin, Alan S

2013-03-01

164

Naturally occurring HCA1 missense mutations result in loss of function: potential impact on lipid deposition  

PubMed Central

The hydroxy-carboxylic acid receptor (HCA1) is a G protein-coupled receptor that is highly expressed on adipocytes and considered a potential target for the treatment of dyslipidemia. In the current study, we investigated the pharmacological properties of naturally occurring variants in this receptor (H43Q, A110V, S172L, and D253H). After transient expression of these receptors into human embryonic kidney 293 cells, basal and ligand-induced signaling were assessed using luciferase reporter gene assays. The A110V, S172L, and D253 variants showed reduced basal activity; the S172L mutant displayed a decrease in potency to the endogenous ligand l-lactate. Both the S172L and D253H variants also showed impaired cell surface expression, which may in part explain the reduced activity of these receptors. The impact of a loss in HCA1 function on lipid accumulation was investigated in the adipocyte cell line, OP9. In these cells, endogenous HCA1 transcript levels rapidly increased and reached maximal levels 3 days after the addition of differentiation media. Knockdown of HCA1 using siRNA resulted in an increase in lipid accumulation as assessed by quantification of Nile Red staining and TLC analysis. Our data suggest that lipid homeostasis may be altered in carriers of selected HCA1 missense variants. PMID:23268337

Doyle, Jamie R.; Lane, Jacqueline M.; Beinborn, Martin; Kopin, Alan S.

2013-01-01

165

Evaluation of naturally occurring radioactive materials (NORM) in the South Western oil wells of Iran.  

PubMed

An investigation was carried out to find out the concentration of Naturally Occurring Radioactive Materials (NORMs) in an oil production unit, an evaporation pond, and a drilling site in the Khuzestan province, in south west Iran the 4th largest oil producing country in the world. The nuclides (232)Th and (40)K were determined in soil samples and (226)Ra was analyzed in both soil and water. The (232)Th ranged between 8.7 and 403Bqkg(-1), while the minimum concentration for (40)K was much larger, i.e. 82Bqkg(-1) and its maximum concentration was 815Bqkg(-1). Soil samples indicated very low concentrations of (226)Ra, typically between 10.6 and 42.1Bqkg(-1) with some exceptions of 282, 602, and even 1480Bqkg(-1). Also, the range for (226)Ra in water was less from 0.1 to a maximum 30.3BqL(-1). Results show that on average, NORM concentrations in these areas are lower in comparison with the usual concentration levels in typical oil and gas fields, but despite this fact, necessary measures have to be taken in order to minimize the environmental impact of radioactive materials. PMID:22321893

Khodashenas, Alireza; Roayaei, Emad; Abtahi, Seyed Mojtaba; Ardalani, Elham

2012-07-01

166

Regulatory Initiatives for Control and Release of Technologically Enhanced Naturally-Occurring Radioactive Materials  

SciTech Connect

Current drafts of proposed standards and suggested State regulations for control and release of technologically-enhanced naturally-occurring radioactive material (TENORM), and standards for release of volumetrically-contaminated material in the US are reviewed. These are compared to the recommendations of the International Atomic Energy Association (IAEA) Safety Series and the European Commission (EC) proposals. Past regulatory efforts with respect to TENORM in the US dealt primarily with oil-field related wastes. Currently, nine states (AK, GA, LA, MS, NM, OH, OR SC, TX) have specific regulations pertaining to TENORM, mostly based on uranium mill tailings cleanup criteria. The new US proposals are dose- or risk-based, as are the IAEA and EC recommendations, and are grounded in the linear no threshold hypothesis (LNT). TENORM wastes involve extremely large volumes, particularly scrap metal and mine wastes. Costs to control and dispose of these wastes can be considerable. The current debate over the validity of LNT at low doses and low dose rates is particularly germane to this discussion. Most standards setting organizations and regulatory agencies base their recommendations on the LNT. The US Environmental Protection Agency has released a draft Federal Guidance Report that recommends calculating health risks from low-level exposure to radionuclides based on the LNT. However, some scientific and professional organizations are openly questioning the validity of LNT and its basis for regulations, practices, and costs to society in general. It is not clear at this time how a non-linear regulatory scheme would be implemented.

Egidi, P.V.

1999-03-02

167

Proteomic comparison of two invasive polychaete species and their naturally occurring F1-hybrids.  

PubMed

The mud worm genus Marenzelleria is highly invasive and is therefore studied intensively. In recently invaded habitats, sympatric populations of the sibling species Marenzelleria viridis and Marenzelleria neglecta are found. In these secondary contact zones, hybridization occurs frequently, revealing incomplete reproductive isolation between these recently diverged species. Two-dimensional polyacrylamide gel electrophoresis (2-DE) and mass spectrometric methods were applied for a comparative analysis of these species and their F(1)-hybrids. Nineteen proteins were identified by cross-species identification strategies. A low degree of interindividual variability within either species allowed characterizing qualitative species-specific differences in 2-DE spot patterns as well as in peptide maps. Species-specific peptides were found in tryptic digests of various proteins, such as glyceraldehyde-3-phosphate dehydrogenase, troponin C, gelsolin-like protein, and peroxiredoxin-1. F(1)-hybrids of M. viridis and M. neglecta showed additivity of protein spot patterns, and the presence of both parental traits was confirmed by mass spectrometric data. This study is one of few dealing with global protein expression in polychaetes and is the first proteomic description of natural F(1)-hybrids in polychaetes. It furthermore indicates the feasibility of proteomic methods for analyses of speciation in Marenzelleria siblings as well as of hybridization events in secondary contact zones in general. PMID:22185356

Blank, Miriam; Mikkat, Stefan; Verleih, Marieke; Bastrop, Ralf

2012-02-01

168

Molecular epidemiology of Streptococcus zooepidemicus infection in naturally occurring equine respiratory disease.  

PubMed

The objective of the study was to characterise the molecular epidemiology of Streptococcus zooepidemicus infection among isolates collected sequentially from recently weaned, pasture maintained Welsh mountain ponies with naturally occurring respiratory disease. Weekly nasopharyngeal and tracheal lavage samplings over a 10-week period were conducted in 29 ponies. Two PCR typing methods based on characterisation of the M-protein hypervariable (HV) region and the 16S-23S rRNA gene intergenic spacer were then applied to isolates of S. zooepidemicus recovered from nasopharyngeal swab and tracheal wash samples. S. zooepidemicus infection was highly prevalent during the study, being isolated from 94% of tracheal washes and 88% of nasopharyngeal swabs. Among 39 different S. zooepidemicus types isolated, more were isolated from the trachea (n=33) than the nasopharynx (n=27). There was evidence from temporal patterns of infection for clonal succession over time by the more prevalent S. zooepidemicus types. Novel S. zooepidemicus types were identified, including previously untyped HV regions and intra-strain multiples of both the HV region and intergenic spacer types. PMID:17433734

Newton, J R; Laxton, R; Wood, J L N; Chanter, N

2008-03-01

169

Two Naturally Occurring Terpenes, Dehydrocostuslactone and Costunolide, Decrease Intracellular GSH Content and Inhibit STAT3 Activation  

PubMed Central

The main purpose of the present study is to envisage the molecular mechanism of inhibitory action ofdehydrocostuslactone (DCE) andcostunolide (CS), two naturally occurring sesquiterpene lactones, towards the activation of signal transducer and activator of transcription 3 (STAT3). We report that, in human THP-1 cell line, they inhibit IL-6-elicited tyrosine phosphorylation of STAT3 and its DNA binding activity with EC50 of 10 M with concomitantdown-regulation ofthe phosphorylation of the tyrosine Janus kinases JAK1, JAK2 and Tyk2. Furthermore, these compounds that contain an ?-?-unsatured carbonyl moiety and function as potent Michael reaction acceptor, induce a rapid drop in intracellular glutathione (GSH) concentration by direct interaction with it, thereby triggering S-glutathionylation of STAT3. Dehydrocostunolide (HCS), the reduced form of CS lacking only the ?-?-unsaturated carbonyl group, fails to exert any inhibitory action. Finally, the glutathione ethylene ester (GEE), the cell permeable GSH form, reverts the inhibitory action of DCE and CS on STAT3 tyrosine phosphorylation. We conclude that these two sesquiterpene lactones are able to induce redox-dependent post-translational modification of cysteine residues of STAT3 protein in order to regulate its function. PMID:21625597

Butturini, Elena; Cavalieri, Elisabetta; Carcereri de Prati, Alessandra; Darra, Elena; Rigo, Antonella; Shoji, Kazuo; Murayama, Norie; Yamazaki, Hiroshi; Watanabe, Yasuo; Suzuki, Hisanori; Mariotto, Sofia

2011-01-01

170

A quantitative analysis of microbially-induced calcite precipitation employing artificial and naturally-occurring sediments  

NASA Astrophysics Data System (ADS)

Microbially-induced calcite precipitation is a strong candidate for the production of sustainable construction materials. The process employs the microbe Sporosarcina pasteurii as an agent to microbially mediate the precipitation of calcium carbonate to bind unconsolidated sediment. As this process can be achieved under ambient temperature conditions and can utilise a wide variety of easily-available sediments, potentially including waste materials, it is envisioned that this procedure could significantly reduce carbon-dioxide emissions in the construction industry. This study describes and quantifies the precipitation of calcite cement in a range of naturally-occurring sediments compared with a control matrix. The study establishes the optimum treatment time for effective cement precipitation in order to produce a material that meets the standards required for construction whilst keeping economic and environmental outlays at a minimum. The 'control sediment' employed industrial-grade glass beads with a grain size range of 595-1180 microns (16-30 US mesh). Sporosarcina pasteurii were mixed in a solution of urea and calcium chloride and then inoculated into the control sediment. The microbes attach to the surface of the sediment grains and employ urea as a source of energy to produce ammonia and carbon dioxide. By so doing, they increase the pH of the solution allowing calcium carbonate to precipitate at the cell walls to act as nucleation points facilitating the precipitation of cements as a grain-coating and biocementing the unconsolidated sediment. The solution treatment was repeated at eight hour intervals with samples removed for detailed analysis after each every five consecutive treatments (i.e. 40 hours). The process was repeated to produce 20 samples with treatment times between 40 and 800 hours. Cemented samples were impregnated with blue epoxy and examined petrographically to monitor cement development. Modal analysis was undertaken on each cemented sample to establish the abundance and natures of precipitated cements. Samples were also examined via SEM to monitor cement distribution and quantify the thickness of cements on grain surfaces and at grain-on-grain contacts. Analysis established that precipitation of calcite continues until 400 hours (50 treatments) after which time there is only an insignificant precipitation of new calcite cement. This is inferred to result from the occlusion of porosity (from 40% to 10%) and observed calcite precipitation at grain-on-grain contacts, both factors reduce the permeability of the samples and, thus, inhibit the flow of solution through the medium. The precipitated calcite cement was found to be dominantly grain-rimming with a consistent thickness averaging 11 microns. A range of naturally-occurring sediments were collected from surface locations throughout the United Arab Emirates. Samples were submitted to a range of petrographic and geochemical analysis in order to quantify grain-size distribution, grain composition and bulk total carbonate content (7.5-94 wt%). Sub-samples of these sediments were established by sieving and the cementation potential of different size fractions was established. Following treatment, these samples were submitted to the same analysis as those employed for the control sediment. A relationship between both sediment grain-size characteristics and sediment grain composition to cement precipitation was established and is discussed.

Lokier, Stephen; Krieg Dosier, Ginger

2013-04-01

171

ISOTOPIC EVIDENCE FOR NATURALLY OCCURRING SULFATE PONDS IN THE KANKAKEE RIVER BASIN, ILLINOIS-INDIANA  

EPA Science Inventory

Design of constructed wetlands in the Kankakee watershed, Indiana, include pumping and distribution ditches leaving former channelized river levees intact. Resultant changes in shallow ground water - surface water interactions may be contributing elevated sulfate to wetland ponds...

172

Residential Proximity to Naturally Occurring Asbestos and Mesothelioma Risk in California  

PubMed Central

Rationale: Little is known about environmental exposure to low levels of naturally occurring asbestos (NOA) and malignant mesothelioma (MM) risk. Objectives: To conduct a cancer registry-based case control study of residential proximity to NOA with MM in California. Methods: Incident MM cases (n = 2,908) aged 35 yr or more, diagnosed between 1988 and 1997, were selected from the California Cancer Registry and frequency matched to control subjects with pancreatic cancer (n = 2,908) by 5-yr age group and sex. Control subjects were selected by stratified random sampling from 28,123 incident pancreatic cancers in the same time period. We located 93.7% of subjects at the house or street level at initial diagnosis. Individual occupational exposure to asbestos was derived from the longest held occupation, available for 74% of MM cases and 63% of pancreatic cancers. Occupational exposure to asbestos was determined by a priori classification and confirmed by association with mesothelioma. Main Results: The adjusted odds ratios and 95% confidence interval for low, medium, and high probabilities of occupational exposures to asbestos were 1.71 (1.322.21), 2.51 (1.913.30), and 14.94 (8.3726.67), respectively. Logistic regression analysis from a subset of 1,133 mesothelioma cases and 890 control subjects with pancreatic cancer showed that the odds of mesothelioma decreased approximately 6.3% for every 10 km farther from the nearest asbestos source, an odds ratio of 0.937 (95% confidence interval = 0.8950.982), adjusted for age, sex, and occupational exposure to asbestos. Conclusions: These data support the hypothesis that residential proximity to NOA is significantly associated with increased risk of MM in California. PMID:15976368

Pan, Xue-lei; Day, Howard W.; Wang, Wei; Beckett, Laurel A.; Schenker, Marc B.

2005-01-01

173

Diversity of Opines and Opine-Catabolizing Bacteria Isolated from Naturally Occurring Crown Gall Tumors  

PubMed Central

The diversity of opines from 43 naturally occurring crown gall tumors on several plant species was analyzed for the presence of agropine, chrysopine, iminodiacid, an unidentified leucinopine-like iminodiacid (IDA-B), mannopine, octopine, nopaline, DL- and LL-succinamopine, leucinopine and heliopine. Opine utilization patterns of agrobacteria and fluorescent pseudomonads resident in a tumor were then analyzed and compared for agreement with the opine isolated from that tumor. Nopaline was the most common opine found and was detected in tumors from cherry, blackberry, grape, and plum. Octopine was not found, although octopine-catabolizing bacteria were isolated from several tumors. A new, previously undescribed iminodiacid of the succinamopine-leucinopine type (provisionally designated IDA-B) was isolated from tumors of wild blackberry. Field tumors from apple, blueberry and grape yielded no detectable opines, even though opine-utilizing bacteria were present. Bacterial isolates from plum and cherry showed the best correspondence between the opine in tumors (nopaline) and the presence of bacteria that catabolized that opine. However, several unusual opine catabolic combinations were identified, including isolates that catabolized a variety of opines but were nonpathogenic. More variability was observed among isolates from field tumors on the remaining plant species. We isolated novel mannopine-nopaline type agrobacteria from field tumors of cherry, plum and blackberry that induced tumors containing either mannopine (plus agropine) or nopaline, but not both. Epidemiologically, the galled plants from an area were not of clonal origin (same Ti plasmid), indicating that the field tumors from a small area were incited by more than one type of Ti plasmid. PMID:16535484

Moore, L. W.; Chilton, W. S.; Canfield, M. L.

1997-01-01

174

Estimated trichloroethene transformation rates due to naturally occurring biodegradation in a fractured-rock aquifer  

USGS Publications Warehouse

Rates of trichloroethene (TCE) mass transformed by naturally occurring biodegradation processes in a fractured rock aquifer underlying a former Naval Air Warfare Center (NAWC) site in West Trenton, New Jersey, were estimated. The methodology included (1) dividing the site into eight elements of equal size and vertically integrating observed concentrations of two daughter products of TCE biodegradationcis-dichloroethene (cis-DCE) and chlorideusing water chemistry data from a network of 88 observation wells; (2) summing the molar mass of cis-DCE, the first biodegradation product of TCE, to provide a probable underestimate of reductive biodegradation of TCE, (3) summing the molar mass of chloride, the final product of chlorinated ethene degradation, to provide a probable overestimate of overall biodegradation. Finally, lower and higher estimates of aquifer porosities and groundwater residence times were used to estimate a range of overall transformation rates. The highest TCE transformation rates estimated using this procedure for the combined overburden and bedrock aquifers was 945 kg/yr, and the lowest was 37 kg/yr. However, hydrologic considerations suggest that approximately 100 to 500 kg/yr is the probable range for overall TCE transformation rates in this system. Estimated rates of TCE transformation were much higher in shallow overburden sediments (approximately 100 to 500 kg/yr) than in the deeper bedrock aquifer (approximately 20 to 0.15 kg/yr), which reflects the higher porosity and higher contaminant mass present in the overburden. By way of comparison, pump-and-treat operations at the NAWC site are estimated to have removed between 1,073 and 1,565 kg/yr of TCE between 1996 and 2009.

Chapelle, Francis H.; Lacombe, Pierre J.; Bradley, Paul M.

2012-01-01

175

Identification of Myeloid Derived Suppressor Cells in Dogs with Naturally Occurring Cancer  

PubMed Central

Dogs with naturally occurring cancer represent an important large animal model for drug development and testing novel immunotherapies. However, poorly defined immunophenotypes of canine leukocytes have limited the study of tumor immunology in dogs. The accumulation of myeloid derived suppressor cells (MDSCs) is known to be a key mechanism of immune suppression in tumor-bearing mice and in human patients. We sought to identify MDSCs in the blood of dogs with cancer. Peripheral blood mononuclear cells (PBMCs) from dogs with advanced or early stage cancer and from age-matched healthy controls were analyzed by flow cytometry and microscopy. Suppressive function was tested in T cell proliferation and cytokine elaboration assays. Semi-quantitative RT-PCR was used to identify potential mechanisms responsible for immunosuppression. PBMCs from dogs with advanced or metastatic cancer exhibited a significantly higher percentage of CD11b+CD14?MHCII? cells compared to dogs diagnosed with early stage non-metastatic tumors and healthy dogs. These CD11b+ CD14?MHCII? cells constitute a subpopulation of activated granulocytes that co-purify with PBMCs, display polymorphonuclear granulocyte morphology, and demonstrate a potent ability to suppress proliferation and IFN-? production in T cells from normal and tumor-bearing donors. Furthermore, these cells expressed hallmark suppressive factors of human MDSC including ARG1, iNOS2, TGF-? and IL-10. In summary our data demonstrate that MDSCs accumulate in the blood of dogs with advanced cancer and can be measured using this three-marker immunophenotype, thereby enabling prospective studies that can monitor MDSC burden. PMID:22428007

Goulart, Michelle R.; Pluhar, G. Elizabeth; Ohlfest, John R.

2012-01-01

176

Regulation of IgA production by naturally occurring TNF/iNOS-producing dendritic cells.  

PubMed

Immunoglobulin-A has an irreplaceable role in the mucosal defence against infectious microbes. In human and mouse, IgA-producing plasma cells comprise approximately 20% of total plasma cells of peripheral lymphoid tissues, whereas more than 80% of plasma cells produce IgA in mucosa-associated lymphoid tissues (MALT). One of the most biologically important and long-standing questions in immunology is why this 'biased' IgA synthesis takes place in the MALT but not other lymphoid organs. Here we show that IgA class-switch recombination (CSR) is impaired in inducible-nitric-oxide-synthase-deficient (iNOS-/-; gene also called Nos2) mice. iNOS regulates the T-cell-dependent IgA CSR through expression of transforming growth factor-beta receptor, and the T-cell-independent IgA CSR through production of a proliferation-inducing ligand (APRIL, also called Tnfsf13) and a B-cell-activating factor of the tumour necrosis factor (TNF) family (BAFF, also called Tnfsf13b). Notably, iNOS is preferentially expressed in MALT dendritic cells in response to the recognition of commensal bacteria by toll-like receptor. Furthermore, adoptive transfer of iNOS+ dendritic cells rescues IgA production in iNOS-/- mice. Further analysis revealed that the MALT dendritic cells are a TNF-alpha/iNOS-producing dendritic-cell subset, originally identified in mice infected with Listeria monocytogenes. The presence of a naturally occurring TNF-alpha/iNOS-producing dendritic-cell subset may explain the predominance of IgA production in the MALT, critical for gut homeostasis. PMID:17713535

Tezuka, Hiroyuki; Abe, Yukiko; Iwata, Makoto; Takeuchi, Hajime; Ishikawa, Hiromichi; Matsushita, Masayuki; Shiohara, Tetsuo; Akira, Shizuo; Ohteki, Toshiaki

2007-08-23

177

Staphylococcal Phenotypes Induced by Naturally Occurring and Synthetic Membrane-Interactive Polyphenolic ?-Lactam Resistance Modifiers  

PubMed Central

Galloyl catechins, in particular (-)-epicatechin gallate (ECg), have the capacity to abrogate ?-lactam resistance in methicillin-resistant strains of Staphylococcus aureus (MRSA); they also prevent biofilm formation, reduce the secretion of a large proportion of the exoproteome and induce profound changes to cell morphology. Current evidence suggests that these reversible phenotypic traits result from their intercalation into the bacterial cytoplasmic membrane. We have endeavoured to potentiate the capacity of ECg to modify the MRSA phenotype by stepwise removal of hydroxyl groups from the B-ring pharmacophore and the A:C fused ring system of the naturally occurring molecule. ECg binds rapidly to the membrane, inducing up-regulation of genes responsible for protection against cell wall stress and maintenance of membrane integrity and function. Studies with artificial membranes modelled on the lipid composition of the staphylococcal bilayer indicated that ECg adopts a position deep within the lipid palisade, eliciting major alterations in the thermotropic behaviour of the bilayer. The non-galloylated homolog (-)-epicatechin enhanced ECg-mediated effects by facilitating entry of ECg molecules into the membrane. ECg analogs with unnatural B-ring hydroxylation patterns induced higher levels of gene expression and more profound changes to MRSA membrane fluidity than ECg but adopted a more superficial location within the bilayer. ECg possessed a high affinity for the positively charged staphylococcal membrane and induced changes to the biophysical properties of the bilayer that are likely to account for its capacity to disperse the cell wall biosynthetic machinery responsible for ?-lactam resistance. The ability to enhance these properties by chemical modification of ECg raises the possibility that more potent analogs could be developed for clinical evaluation. PMID:24699700

Palacios, Lucia; Rosado, Helena; Micol, Vicente; Rosato, Adriana E.; Bernal, Patricia; Arroyo, Raquel; Grounds, Helen; Anderson, James C.; Stabler, Richard A.; Taylor, Peter W.

2014-01-01

178

Naturally occurring secondary nutritional hyperparathyroidism in cattle egrets (Bubulcus ibis) from central Texas.  

PubMed

Naturally occurring secondary nutritional hyperparathyroidism is described in the nestlings of two colonies of cattle egrets (Bubulcus ibis) from Central Texas (Bryan and San Antonio, Texas, USA). Nestlings from a third colony (Waco, Texas, USA) were collected in a subsequent year for comparison. Birds from the first two colonies consistently had severe osteopenia and associated curving deformities and folding fractures of their long bones. These birds also had reduced bone ash, increased osteoclasia, a marked decrease in osteoblast activity, variable lengthening and shortening of the hypertrophic zone of the epiphyseal cartilage, decreased and disorganized formation of new bone, and a marked hypertrophy and hyperplasia of the parathyroid glands as compared to birds collected from the third colony. Fibrous osteodystrophy was found in all of the birds from San Antonio and Bryan. Evidence of moderate to severe calcium deficiency was also identified in 33% of the cattle egrets collected from Waco. Gut contents of affected chicks contained predominately grasshoppers and crickets; vertebrate prey items were absent from the Bryan birds. Grasshoppers and crickets collected from fields frequented by the adult egrets in 1994 had 0.12-0.28% calcium and 0.76-0.81% phosphorus. Pooled grasshoppers and crickets collected during a subsequent wet early spring averaged 0.24% calcium and 0.65% phosphorus. Although the phosphorus content of the insect prey was adequate for growth, calcium was approximately one-third the minimum calcium requirement needed for growth for other species of birds. It was postulated that cattle egrets breeding in Central Texas have expanded their range into habitat that contains less vertebrate prey, and as a result, many nestling egrets are being fed diets that contain suboptimal calcium. Therefore, in years where vertebrate prey is scarce and forage for insect prey is reduced in calcium, nestling egrets are at risk for developing secondary nutritional hyperparathyroidism. PMID:16107676

Phalen, David N; Drew, Mark L; Contreras, Cindy; Roset, Kimberly; Mora, Miguel

2005-04-01

179

Acute Toxicological Responses of Fischer Rats to Naturally Occurring Asbestos from theUnited States and Canada  

EPA Science Inventory

This study was designed to provide understanding of the toxicity of naturally occurring asbestos (NOA) including Libby amphibole (LA), Sumas Mountain chrysotile (SM), EI Dorado Hills tremolite (ED) and Ontario actinolite/ferroactinolite cleavage fragments (ON). Ratrespirable fra...

180

Modulation of cytochrome P450 enzyme activity and PAH-induced skin carcinogenesis by naturally occurring coumarins  

Microsoft Academic Search

The present study was designed to determine the potential anticarcinogenic activity of naturally occurring coumarins and their mechanism of action. The results indicated that several naturally occurring coumarins including bergamottin, coriandrin, imperatorin, isopimpinellin, and ostruthin, to which humans are routinely exposed in the diet, were effective inhibitors and\\/or inactivators of CYP1A1-mediated ethoxyresorufin-O-dealkylase (EROD) or CYP2B1-mediated pentoxyresorufin-O-dealkylase (PROD) in mouse liver

Yingna Cai

1996-01-01

181

Multi-Isotope Analysis as a Natural Reaction Probe of Biodegradation Mechanisms of 1,2- Dichloroethane  

NASA Astrophysics Data System (ADS)

1,2-Dichloroethane (1,2-DCA), a chlorinated aliphatic hydrocarbon, is an EPA priority pollutant and a widespread groundwater contaminant. Stable isotope fractionation during biodegradation of 1,2-DCA occurs due to differences in the reaction rates of heavy versus light atoms present at a reacting bond in the 1,2-DCA molecule. In general, light isotopic bonds react more quickly, producing a relative enrichment in the heavy isotope in the remaining contaminant pool. Compound specific isotope analysis has the potential to demonstrate the occurrence and extent of biodegradation at chlorinated solvent contaminated groundwater sites. In this study, stable carbon isotope fractionation was used as a novel reaction probe to provide information about the mechanism of 1,2-DCA biodegradation. Isotopic fractionation was measured during 1,2-DCA degradation by a microbial culture capable of degrading 1,2-DCA under O2-reducing and NO3-reducing conditions. The microbial culture produced isotopic enrichment values that are not only large and reproducible, but are the same whether O2 or NO3 was used as an electron acceptor. The mean isotopic enrichment value of -25.8 permil measured for the microbial culture during 1,2-DCA degradation under both O2 and NO3- reducing conditions can be converted into a kinetic isotope effect (KIE) value to relate the observed isotopic fractionation to the mechanism of degradation. This KIE value (1.05) is consistent with degradation via a hydrolysis (SN2) reaction under both electron-accepting conditions. Isotope analysis was able to provide a first line of evidence for the reaction mechanism of 1,2-DCA biodegradation by the microbial culture. Using a multi-isotope approach incorporating both carbon and hydrogen isotopic data, compound specific isotope analysis also has the potential to determine degradation mechanisms for 1,2-DCA under aerobic conditions where 1,2-DCA is known to be degraded by two distinct enzymatic pathways. Biodegradation of 1,2-DCA via a hydrolysis (SN2) reaction produces a large carbon isotope enrichment (isotopic enrichment factor = -29.2 permil) while oxidation of 1,2-DCA via a monooxygenase enzyme produces a small carbon isotope enrichment (isotopic enrichment factor = -3.9 permil). Conversely, because a hydrogen bond is not broken in the hydrolysis (SN2) reaction, only a small secondary hydrogen isotope enrichment is expected, while a large hydrogen isotope enrichment is expected during oxidation of 1,2-DCA via a monooxygenase enzyme. The complementary information of both carbon and hydrogen isotopic data may be instrumental in identifying the mechanism of biodegradation in the subsurface, and illustrates the potential of compound specific isotope analysis as a natural reaction probe to provide insight into the enzymatic mechanism of subsurface contaminant degradation.

Hirschorn, S. K.; Dinglasan-Panlilio, M.; Edwards, E. A.; Lacrampe-Couloume, G.; Sherwood Lollar, B.

2006-12-01

182

The effect of colloid formulation on colloid osmotic pressure in horses with naturally occurring gastrointestinal disease  

PubMed Central

Background Naturally occurring gastrointestinal disease is an important cause of acute hypoproteinemia in adult horses and hydroxyethyl starch colloid fluid treatment is a component of supportive care in these cases to improve plasma volume and maintain colloid osmotic pressure (COP). The objectives of the present study were to compare 2 formulations of high molecular weight hydroxyethyl starch and their relative effect on COP, acid-base status, and survival of horses with acute hypoproteinemia secondary to gastrointestinal disease. Methods Twenty adult horses, ? 1 year of age, were prospectively enrolled, with informed client consent, if they developed acute hypoproteinemia, defined as a plasma total protein <5.0 g/dL or albumin <2.2 g/dL during hospitalization while undergoing treatment for gastrointestinal disease. Horses were randomly assigned to receive a rapid infusion of either 6% hydroxyethyl starch in 0.9% saline or 6% hydroxyethyl starch in lactated ringers solution at a dose of 10ml/kg. Venous blood gas analysis, COP, and PCV were evaluated before and after colloid administration. Results For both groups, average COP prior to treatment was 11.0 mmHg (9.7 12.2 mmHg) and post colloid treatment was 13.2 mmHg (12.0 -14.7 mmHg) [Normal range 18 22 mmHg]. COP was significantly increased with colloid treatment (p<0.001) but this increase was not significantly different between treatment groups. Venous pH did not change significantly with treatment. Twelve horses survived to hospital discharge and survival did not differ significantly between treatment groups. Conclusions Post-treatment COP improved approximately 20% regardless of the formulation used, however, values did not reach the normal range of COP observed in healthy horses. Acid-base parameters were not significantly impacted by either treatment. Further study is needed to determine how these two products compare with regards to other outcome measures. Evaluation of the relative effects of colloid formulation in horses with clinical disease is a future area of interest. PMID:25237987

2014-01-01

183

Manufactured Home Testing in Simulated and Naturally Occurring High Winds for WCTE Conference  

SciTech Connect

A typical double-wide manufactured home was tested in simulated and naturally occurring high winds to understand structural behavior and improve performance during severe windstorms. Seven (7) lateral load tests were conducted on a double-wide manufactured home at a remote field test site in Wyoming. An extensive instrumentation package monitored the overall behavior of the home and collected data vital to validating computational software for the manufactured housing industry. The tests were designed to approach the design load of the home without causing structural damage, thus allowing the behavior of the home to be accessed when the home was later exposed to high winds (to 80-mph). The data generally show near-linear initial system response with significant non-linear behavior as the applied loads increase. Load transfer across the marriage line is primarily compression. Racking, while present, is very small. Interface slip and shear displacement along the marriage line are nearly insignificant. Horizontal global displacements reached 0.6 inch. These tests were designed primarily to collect data necessary to calibrate a desktop analysis and design software tool, MHTool, under development at the Idaho National Laboratory specifically for manufactured housing. Currently available analysis tools are, for the most part, based on methods developed for "stick built" structures and are inappropriate for manufactured homes. The special materials utilized in manufactured homes, such as rigid adhesives used in the connection of the sheathing materials to the studs, significantly alter the behavior of manufactured homes under lateral loads. Previous full scale tests of laterally loaded manufactured homes confirm the contention that conventional analysis methods are not applicable. System behavior dominates the structural action of manufactured homes and its prediction requires a three dimensional analysis of the complete unit, including tie-downs. This project was sponsored by the US Department of Energy, US Department of Housing and Urban Development, and the Manufactured Housing Institute. The results of this research can lead to savings in annual losses of life and property by providing validated information to enable the advancement of code requirements and by developing engineering software that can predict and optimize wind resistance.

William D. Richins; Thomas K. Larson; Jeffrey M. Lacy; Ryan G. Kobbe

2006-08-01

184

Isotope shifts of natural Sr+ measured by laser fluorescence in a sympathetically cooled Coulomb crystal  

E-print Network

We measured by laser spectroscopy the isotope shifts between naturally-occurring even-isotopes of strontium ions for both the $5s\\,\\,^2S_{1/2}\\to 5p\\,\\,^2P_{1/2}$ (violet) and the $4d\\,\\,^2D_{3/2}\\to 5p\\,\\,^2P_{1/2}$ (infrared) dipole-allowed optical transitions. Fluorescence spectra were taken by simultaneous measurements on a two-component Coulomb crystal in a linear Paul trap containing $10^3$--$10^4$ laser-cooled Sr$^+$ ions. The isotope shifts are extracted from the experimental spectra by fitting the data with the analytical solution of the optical Bloch equations describing a three-level atom in interaction with two laser beams. This technique allowed us to increase the precision with respect to previously reported data obtained by optogalvanic spectroscopy or fast atomic-beam techniques. The results for the $5s\\,\\,^2S_{1/2}\\to 5p\\,\\,^2P_{1/2}$ transition are $\

Brice Dubost; Romain Dubessy; Benjamin Szymanski; Samuel Guibal; Jean-Pierre Likforman; Luca Guidoni

2014-02-14

185

Stable isotopes of nitrate reflect natural attenuation of propellant residues on military training ranges.  

PubMed

Nitroglycerin (NG) and nitrocellulose (NC) are constituents of double-base propellants used notably for firing antitank ammunitions. Nitroglycerin was detected in soil and water samples from the unsaturated zone (pore water) at an active antitank firing position, where the presence of high nitrate (NO3(-)) concentrations suggests that natural attenuation of NG is occurring. However, concentrations alone cannot assess if NG is the source of NO3(-), nor can they determine which degradation processes are involved. To address this issue, isotopic ratios (?(15)N, ?(18)O) were measured for NO3(-) produced from NG and NC through various controlled degradation processes and compared with ratios measured in field pore water samples. Results indicate that propellant combustion and degradation mediated by soil organic carbon produced the observed NO3(-) in pore water at this site. Moreover, isotopic results are presented for NO3(-) produced through photolysis of propellant constituents, which could be a dominant process at other sites. The isotopic data presented here constitute novel information regarding a source of NO3(-) that was practically not documented before and a basis to study the contamination by energetic materials in different contexts. PMID:23815525

Bordeleau, Genevive; Savard, Martine M; Martel, Richard; Smirnoff, Anna; Ampleman, Guy; Thiboutot, Sonia

2013-08-01

186

Investigation of Naturally Occurring Radio Nuclides in Shir-kuh Granites  

SciTech Connect

One of the principle natural radiation resources is Granite which can be dangerous for human because of its radiations. Based on this fact, in this research we attempt to specify the activity amount of these natural radio nuclides, existing in Shir-kuh Granite of Yazd state. To specify the activity amount of this natural radio nuclides, it has been applied the measurement method of Gamma spectroscopy using high purity Germanium (HPGe) detector.

Mazarei, Mohammad Mehdi; Zarei, Mojtaba [Department of Science, Bushehr Branch, Islamic Azad University, City of Aalishahr, Bushehr Province, Iran P.O.Box: 7519619555 (Iran, Islamic Republic of)

2011-12-26

187

AcuteToxicological Responses of Fischer Rats to Naturally Occurring Asbestos Samples from the United States and Canada  

EPA Science Inventory

The potential public health issues related to exposure to natural asbestos deposits (commonly termed naturally occurring asbestos, NO A) has gained the regulatory and media spotlight in recent years. Arguably the most well known example is Libby, Montana, the site of the largest ...

188

Deep-Sea Research I 51 (2004) 11591168 Global distribution of naturally occurring marine  

E-print Network

and bathyal sea floor, where dissolved oxygen is o0.5 ml l?1 ; over half (59%) occurs in the northern Indian conditions. r 2004 Elsevier Ltd. All rights reserved. Keywords: Dissolved oxygen; Oxygen minimum zone; OMZ and is decomposed in mid- water, consuming dissolved oxygen. When high oxygen demand occurs in combination

Levin, Lisa

189

Serological evidence for naturally occurring transmission of Neospora caninum among foxes ( Vulpes vulpes)  

Microsoft Academic Search

The study describes the time course of the Neospora caninum-specific antibody response in experimentally infected foxes, in naturally N. caninum-seropositive vixens and their litters. An immunofluorescence test, a tachyzoite surface antigen based ELISA and an immunoblot assay were established for this purpose. The immunoblot patterns of naturally seropositive and experimentally infected foxes revealed a high degree of similarity and resembled

G. Schares; U. Wenzel; T. Mller; F. J. Conraths

2001-01-01

190

Demonstration of significant abiotic iron isotope fractionation in nature  

USGS Publications Warehouse

Field and laboratory studies reveal that the mineral ferrihydrite, formed as a result of abiotic oxidation of aqueous ferrous to ferric Fe, contains Fe that is isotopically heavy relative to coexisting aqueous Fe. Because the electron transfer step of the oxidation process at pH >5 is essentially irreversible and should favor the lighter Fe isotopes in the ferric iron product, this result suggests that relatively heavy Fe isotopes are preferentially partitioned into the readily oxidized Fe(II)(OH)x(aq) species or their transition complexes prior to oxidation. The apparent Fe isotope fractionation factor, ??ferrihydrite-water, depends primarily on the relative abundances of the Fe(II)(aq) species. This study demonstrates that abiotic processes can fractionate the Fe isotopes to the same extent as biotic processes, and thus Fe isotopes on their own do not provide an effective biosignature.

Bullen, T. D.; White, A. F.; Childs, C. W.; Vivit, D. V.; Schultz, M. S.

2001-01-01

191

Naturally Occurring Arsenic in Ground Water, Norman, Oklahoma, 2004, and Remediation Options for Produced Water  

USGS Publications Warehouse

In 2000, the U.S. Environmental Protection Agency (EPA) reviewed the arsenic drinking water standard for public water supplies. Considering the available research and statistics on the health effects of arsenic ingestion, the EPA reduced the Maximum Contaminant Level (MCL) for public drinking water from 50 micrograms per liter (?g/L) to 10 ?g/L (U.S. Environmental Protection Agency, 2001a). As a result of the more stringent standard, the EPA estimates that about 3,000 public water providers across the United States must take action to meet the new standard before it becomes effective on January 23, 2006 (U.S. Environmental Protection Agency, 2001b). The City of Norman (City) is one of several Oklahoma municipalities affected by the new arsenic standard. About 20 percent of Norman?s water is supplied by wells completed in the Central Oklahoma (Garber-Wellington) aquifer; the rest is supplied by Lake Thunderbird (fig. 1) or purchased from Oklahoma City. The Norman well field is composed of 24 active wells, and water produced from about half of the wells will not be in compliance with the new MCL (figs. 2 and 3). Chemical treatment of water with elevated arsenic is possible, but it is generally cost prohibitive. Another costly solution is simply to abandon the high-arsenic wells and replace them with new wells in low-arsenic areas. In the next phase of well construction beginning in 2005, the City plans to construct as many as 30 new wells in northeast Norman (Bryan Mitchell, City of Norman, oral commun., 2005). The new wells will replace production lost to the new arsenic standard and add new production to keep pace with rapidly growing consumer demand. Well modification to exclude arsenic-bearing water from existing wells is a more cost-effective solution, but it requires a great deal of knowledge about local aquifer properties and individual well dynamics to decide which wells are good candidates for modification. With the goal of determining if well modification can be used to bring some of Norman?s high-arsenic wells into compliance with the new arsenic standard, the EPA Office of Research and Development (ORD) initiated a three-year research project in 2003 with participation from the U.S. Geological Survey (USGS), Oklahoma State University, and the City of Norman. The primary objectives of the project are to: (1) determine where naturally occurring arsenic is entering wells by collecting water samples at different depths, (2) investigate the utility of new methods for collecting water-quality data in a pumping well, (3) better understand the stratigraphy and composition of aquifer rocks, (4) assess 10 wells for the possibility of arsenic remediation by well modification, and (5) evaluate the effectiveness of well modification in bringing marginal wells into compliance with the new arsenic MCL. The purpose of this report is to describe the occurrence of arsenic in ground water near Norman, Oklahoma, and available options for reducing arsenic concentrations in produced ground water.

Smith, S. Jerrod; Christenson, Scott

2005-01-01

192

Zinc isotope variations in natural and cultured marine phytoplankton.  

NASA Astrophysics Data System (ADS)

Zn is an essential micronutrient for marine phytoplankton. Zn distribution in the ocean is largely controlled by biological uptake, being drawn down from several nanomolar concentrations in the deep ocean to picomolar concentrations in the surface ocean. Zn isotopes may record this biological activity based on the preferential uptake of lighter Zn isotopes by phytoplankton. Marechal et. al. (2000) attribute a seasonal cycle in the Zn isotope composition of sediment trap material and global variations in the Zn isotope composition of manganese nodules to this biological fractionation. To better understand the processes controlling the distribution of Zn isotopes in the ocean, the isotopic composition of phytoplankton was investigated. In-situ plankton were collected by trace metal clean plankton tows from both the Atlantic and Pacific Oceans. In a region close to a continental source of Zn, approximately 300 km off the coast of Brazil (7.4 S, 31.4 W), the isotope composition of the plankton tow material closely resembles that of continental material. The isotopic composition of plankton tows from more remote locations in the open ocean may better record the effects of biological cycling. Additional samples from the Atlantic, as well as samples from the central Pacific near Hawaii and the North Pacific are being processed. This data may be used to better understand how biological processes control the global distribution of Zn isotopes in the oceans.

John, S. G.; Bergquist, B. A.; Boyle, E. A.

2004-12-01

193

Retinoid X Receptor-Dependent Transactivation by a Naturally Occurring Structural Variant of Human Constitutive  

E-print Network

6 and CYP3A4 gene enhancers, exhibiting both ligand- and RXR-dependence. These results demonstrate. Furthermore, results of transfec- tion assays reveal that CAR3 is capable of transactivating the natural CYP2B

Omiecinski, Curtis

194

Evaluation of naturally occurring parasitic Hymenoptera attacking silverleaf whitefly, Bemisia argentifolii in Texas  

E-print Network

. californicus was the second most abundant species, at times outnumbering E pergandiella; usually at low whitefly densities. Encarsia nigricephala, E sp. nr. strenua and E. quaintancei were also collected. Evaluation of these natural enemies emphasized...

Moomaw, Charles Philip

2012-06-07

195

Nitrate dynamics in natural plants: insights based on the concentration and natural isotope abundances of tissue nitrate  

PubMed Central

The dynamics of nitrate (NO?3), a major nitrogen (N) source for natural plants, has been studied mostly through experimental N addition, enzymatic assay, isotope labeling, and genetic expression. However, artificial N supply may not reasonably reflect the N strategies in natural plants because NO?3 uptake and reduction may vary with external N availability. Due to abrupt application and short operation time, field N addition, and isotopic labeling hinder the elucidation of in situ NO?3-use mechanisms. The concentration and natural isotopes of tissue NO?3 can offer insights into the plant NO?3 sources and dynamics in a natural context. Furthermore, they facilitate the exploration of plant NO?3 utilization and its interaction with N pollution and ecosystem N cycles without disturbing the N pools. The present study was conducted to review the application of the denitrifier method for concentration and isotope analyses of NO?3 in plants. Moreover, this study highlights the utility and advantages of these parameters in interpreting NO?3 sources and dynamics in natural plants. We summarize the major sources and reduction processes of NO?3 in plants, and discuss the implications of NO?3 concentration in plant tissues based on existing data. Particular emphasis was laid on the regulation of soil NO?3 and plant ecophysiological functions in interspecific and intra-plant NO?3 variations. We introduce N and O isotope systematics of NO?3 in plants and discuss the principles and feasibilities of using isotopic enrichment and fractionation factors; the correlation between concentration and isotopes (N and O isotopes: ?18O and ?17O); and isotope mass-balance calculations to constrain sources and reduction of NO?3 in possible scenarios for natural plants are deliberated. Finally, we offer a preliminary framework of intraplant ?18O-NO?3 variation, and summarize the uncertainties in using tissue NO?3 parameters to interpret plant NO?3 utilization. PMID:25101106

Liu, Xue-Yan; Koba, Keisuke; Makabe, Akiko; Liu, Cong-Qiang

2014-01-01

196

Neutron transmutation doped natural and isotopically engineered germanium thermistors  

NASA Astrophysics Data System (ADS)

We report on the development, fabrication and performance of a new class of thermal sensors for far IR and millimeter wave detection. These devices consist of small single crystal samples of ultra-pure, natural or isotopically engineered germanium which have been doped by the neutron transmutation doping (NTD) technique. The concentrations of the acceptor and donor dopants (N(subscript A),N(subscript D)) can be accurately controlled with this technique. They depend on the thermal neutron fluence, the neutron absorption cross sections and the atomic fractions of (superscript 70)Ge (for the Ga acceptors) and (superscript 74)Ge (for the As donors), respectively. The values of N(subscript A) and N(subscript D) and their ratio result in a predictable resistivity of the Ge crystals down to temperatures of a few milliKelvin. The excellent control of the resistivity down to very low temperatrues, together with the development of ohmic contacts working at the lowest temperatures, allows the fabrication of high sensitivity bolometer arrays with over 100 pixels and highly uniform response.

Haller, Eugene E.; Itoh, K. M.; Beeman, Jeffrey W.; Hansen, William L.; Ozhogin, V. I.

1994-06-01

197

Determination of lithium isotopes at natural abundance levels by atomic absorption spectrometry  

USGS Publications Warehouse

The relationships of the absorption of 6Li and 7Li hollow cathode lamp emissions are used to determine lithium isotopic composition in the natural abundance range of geologic materials. Absorption was found to have a nonlinear dependence upon total lithium concentration and isotopic composition. A method using nonlinear equations to describe the relationship of the absorption of 6Li and 7Li lamp radiation is proposed as a means of calculating isotopic composition that is independent of total lithium concentration.

Meier, A.L.

1982-01-01

198

Potential use of naturally occurring sulphuric acid to beneficiate poorly soluble phosphate from Eppawala, Sri Lanka  

Microsoft Academic Search

A 29 000 yr old high-sulphur peat deposit occurs in the western district of Colombo, Sri Lanka. This permanently submerged deposit has several pyrite-rich layers in 8 to 10 m sequences and is connected to the open ocean. Sea water intrudes to the peat deposit during tidal movements. Villagers have excavated the peat to form islands which serve as foundations

Kapila Dahanayake; Atula Senaratne; S. M. N. D. Subasinghe; A. Liyanaarachchi

1991-01-01

199

The nitrogen cycle in cryoconites: naturally occurring nitrification-denitrification granules on a glacier.  

PubMed

Cryoconites are microbial aggregates commonly found on glacier surfaces where they tend to take spherical, granular forms. While it has been postulated that the microbes in cryoconite granules play an important role in glacier ecosystems, information on their community structure is still limited, and their functions remain unclear. Here, we present evidence for the occurrence of nitrogen cycling in cryoconite granules on a glacier in Central Asia. We detected marker genes for nitrogen fixation, nitrification and denitrification in cryoconite granules by digital polymerase chain reaction (PCR), while digital reverse transcription PCR analysis revealed that only marker genes for nitrification and denitrification were abundantly transcribed. Analysis of isotope ratios also indicated the occurrence of nitrification; nitrate in the meltwater on the glacier surface was of biological origin, while nitrate in the snow was of atmospheric origin. The predominant nitrifiers on this glacier belonged to the order Nitrosomonadales, as suggested by amoA sequences and 16S ribosomal RNA pyrosequencing analysis. Our results suggest that the intense carbon and nitrogen cycles by nitrifiers, denitrifiers and cyanobacteria support abundant and active microbes on the Asian glacier. PMID:24946985

Segawa, Takahiro; Ishii, Satoshi; Ohte, Nobuhito; Akiyoshi, Ayumi; Yamada, Akinori; Maruyama, Fumito; Li, Zhongqin; Hongoh, Yuichi; Takeuchi, Nozomu

2014-10-01

200

Naturally occurring radionuclides in food and drinking water from a thorium-rich area.  

PubMed

This paper focuses on a survey of uranium and thorium decay chain radionuclides in food and drinking water from the thorium-rich (monazite-bearing) region of Buena, which is located in the state of Rio de Janeiro, Brazil. The radionuclide concentration values in the food and drinking water from Buena reached values higher than 100-fold the international reference values. The daily intake of radionuclides by the local population is similar to that of another high background radiation area in Brazil, but the intake is higher than that of residents from a normal background radiation area. Approximately 58 % of the food consumed by Buena inhabitants is produced locally. Based on that figure, locally produced food and the dilution of total radionuclides in the diet of residents caused by food importation are both highly relevant to a population's intake of radionuclides. The concentration values for (210)Pb and the radium isotopes in drinking water from Buena are among the highest values to be reported in the literature. (228)Ra is the most important radionuclide ingested with both food and water among the inhabitants of Buena. PMID:22782172

da Costa Lauria, Dejanira; Rochedo, Elaine R R; Godoy, Maria Luisa D P; Santos, Eliane E; Hacon, Sandra S

2012-11-01

201

INFLUENCE OF NATURALLY OCCURRING HUMIC ACIDS ON BIODEGRADATION OF MONOSUBSTITUTED PHENOLS BY AQUATIC BACTERIA  

EPA Science Inventory

Samples of the microbial community from Lake Michie, a mesotrophic reservoir in central North Carolina, were adapted to various levels (100 to 1,000 micrograms/liter) of natural humic acids in chemostats. Adaptation to increasing levels of humic acids significantly reduced the ab...

202

Laboratory studies using naturally occurring green rust to aid metal mine water remediation  

Microsoft Academic Search

Green rust, an Fe (II) and (III) oxyhydroxy salt, can alter the aqueous oxidation state, mobility and toxicity, of inorganic contaminants and thus could have applications in water treatment. This paper discusses a series of stirred, open batch experiments designed to evaluate green rust, and its oxidised equivalent in this context comparing it to a ferrihydrite\\/goethite ochre. Natural green rust

Jenny M. Bearcock; William T. Perkins; Nicholas J. G. Pearce

2011-01-01

203

Naturally Occurring Proteasome Inhibitors from Mate Tea (Ilex paraguayensis) Serve as Models for Topical Proteasome Inhibitors  

Microsoft Academic Search

Proteasome inhibitors have emerged as a clinically important therapy for neoplastic disease, with velcade, an organoboron compound used extensively in multiple myeloma. Recently, (?)-epigallocatechin gallate has been found to be a potent inhibitor of the proteasomal chymotrypsin-like activity. Other compounds that inhibit angiogenesis and are active as chemopreventive agents, such as curcumin, also inhibit proteasome activity. We have screened natural

Jack L Arbiser; Xing-Cong Li; Chowdhury Fiaz Hossain; Dale G Nagle; David M Smith; Paul Miller; Baskaran Govindarajan; Josh Di Carlo; Kristin R Landis-Piwowar; Q Ping Dou

2005-01-01

204

Algal products as naturally occurring modulators for the multidrug resistance (MDR) transporter  

Microsoft Academic Search

Extracts of various algae show modulating activity of the multidrug resistance (MDR) transporter in the mussel Mytilus californianus. Mytilus californianus is a filter feeder that removes seaweed particulates, phytoplankton and their byproducts from the water. The gills of Mytilus californianus express high MDR titer and activity possibly to provide protection from natural toxins in the diet. To test this hypothesis,

N. Eufemia; S. Girshick; D. Epel

2000-01-01

205

DISTRIBUTION OF NATURALLY OCCURRING RADIONUCLIDES (U, Th) IN TIMAHDIT'S BLACK SHALE (MOROCCO)  

E-print Network

is partitioned between silicate minerals and pyrite. Keywords: uranium - thorium - black shale - mineralogy their natural intrinsic content in uranium and thorium. A black shale collected from Timahdit (Morocco, 230 Th, 228 Th have multiples modes of occurrence in the Moroccan's black shale. Uranium

Paris-Sud XI, Université de

206

The element arsenic occurs naturally in dif-ferent forms, which may be classified  

E-print Network

as organic or inorganic. Arsenic is distributed widely in rocks, soil, water and air--and in living things by human activities. Natural concen- trations of arsenic in soil typically range from 0.1 to 40 parts per or alkalinity of the water (pH) · amount of iron in the water · amount of metal sulfide and sulfide in the water

207

Cooker's sloshing experiment with baffles: a naturally occurring multifold 1: :1 resonance  

E-print Network

discovered a physical system that has an (n + 1)-fold 1 : · · · : 1 resonance for any natural number n : 1 : 1 : 1 resonance are rarer than the 1 : 1 resonance but examples have been discovered. An example of tri-fold resonance is triply- degenerate vibrations of tetrahedral molecules in chemistry (e

Bridges, Tom

208

Naturally occurring spinal hyperostosis in dogs as a model for human spinal disorders.  

PubMed

Both spondylosis and diffuse idiopathic skeletal hyperostosis (DISH) are prevalent in humans and are considered distinct entities. Nowadays, the term spondylosis is in the biomedical literature mostly used when concurrently degenerative disc disease is present. In companion animals, many reports on spondylosis, often without intervertebral disc degeneration, are described. The nomenclature and the definitions of both spondylosis and DISH in biomedical and veterinary literature should be more in line to facilitate comparison. Spondylosis and DISH occur in dogs spontaneously and can co-occur in one animal. Specifically, Boxers may serve as translational disease models for the elucidation of the gene(s) involved in the (etio)pathogenesis of spondylosis and DISH or serve as a test population for newly developed treatment options. PMID:24936035

Kranenburg, Hendrik-Jan C; Hazewinkel, Herman A W; Meij, Bjrn P

2014-01-01

209

Effect of temperature, pH, and oxygen level on the multiplication of naturally occurring Legionella pneumophila in potable water.  

PubMed Central

A water culture containing naturally occurring Legionella pneumophila and associated microbiota was maintained in the laboratory by serially transferring the culture in tap water which had been sterilized by membrane filtration. Successful maintenance of the water culture depended upon transferring the culture when the growth of L. pneumophila was in the late-exponential to early-stationary phase. The water culture was used as a source of naturally occurring bacteria to determine some of the parameters which affect the multiplication of L. pneumophila in tap water. Naturally occurring L. pneumophila multiplied at a temperature between 25 and 37 degrees C, at pH levels of 5.5 to 9.2, and at concentrations of dissolved oxygen of 6.0 to 6.7 mg/liter. Multiplication did not occur in tap water which contained less than 2.2 mg of dissolved oxygen per liter. An association was observed between the multiplication of L. pneumophila and the non-Legionellaceae bacteria which were also present in the water culture. The method of preserving naturally occurring L. pneumophila and associated microbiota may facilitate studies on the symbiosis of L. pneumophila with other microorganisms. PMID:4004233

Wadowsky, R M; Wolford, R; McNamara, A M; Yee, R B

1985-01-01

210

Defining the Origin and Nature of the Tristan da Cunha Plume Source Using He Isotope and Pb Isotope Modelling  

NASA Astrophysics Data System (ADS)

We present new He and Pb isotope and trace element data for Inaccessible Island and Tristan da Cunha, which confirms narrow ranges in He isotopes (5.5Ra+-0.6) and Pb isotopes (207Pb/206Pb=18.59+-0.10; 207Pb/204Pb=15.54+-0.01) and enrichment in incompatible elements (La/Yb=22-38) for the Tristan plume. We use this data to test models on the nature of the Tristan plume source. Helium isotope systematics (5.5Ra) indicate that the Tristan plume source is degassed relative to MORB-source mantle. This combined with distinctive Pb isotope systematics has lead to the theory that the Tristan plume constitutes recycled oceanic and continental lithosphere. Tristan's He isotope composition is more radiogenic than modelled degassed recycled oceanic crust (<0.0001Ra). A component of unradiogenic He is required in the source of the Tristan plume. There are two possible scenarios to explain Tristan's He isotope composition. (1)Subducted lithosphere retains sufficient He during subduction to remain relatively unradiogenic. (2)Degassed recycled material mixes with a unradiogenic He isotope component. If He is not perfectly incompatible than subducted oceanic lithosphere could lose U and He to similar degrees such that U/He ratios do not change significantly, which would lead to minor changes in the He isotope composition of subducted oceanic lithosphere. There is insufficient evidence that He and U have similar compatibilities during melting. T he unradiogenic He isotope component is likely to be primitive undegassed mantle material. Here we investigate two end-member possibilities. 1 A high Ra source analogous to Hawaii and Iceland: This requires a very small contribution from a source with high He concentration (9ppb He for 20ppb U) and unradiogenic He isotope composition (40 Ra). The contribution is sufficiently small (>1%) that it is not distinguishable using other geochemical tools. 2 A primitive mantle component with a Ra of 5.5: The Tristan plume has Pb, Nd and Sr isotope systematics very close to Bulk Earth. The Tristan volcanics were not considered to be melts of primitive mantle because of their low Ra. If, however, degassing of the lower mantle was not homogenous in the early Earth (i.e. primitive U/He ratios vary) it is possible that primitive mantle material could have remained isolated with a Ra lower than the MORB-source mantle. For Tristan 6.7ppb He and 20ppb U will produce a Ra of 5.5 over the lifetime of the Earth.

Murphy, D. T.; Ballentine, C.; Burgess, R.

2005-12-01

211

Impacts of naturally-occurring soil fungi on seeds of meadow plants  

Microsoft Academic Search

Although soil fungi may represent an ecologically important cause of mortality of buried seeds, few studies have provided\\u000a direct evidence of the pathogenicity of fungi colonizing seeds in natural habitats. In response, we conducted a series of\\u000a experiments to investigate the impacts of soil fungi from a range of habitats on seeds of meadow plants. We compared the survival\\u000a of

Michelle Schafer; Peter M. Kotanen

2004-01-01

212

Algal products as naturally occurring substrates for p-glycoprotein in Mytilus californianus  

Microsoft Academic Search

Mytilus californianus is a filter feeder that removes seaweed particulates, phytoplankton, and their byproducts from the water. The gills of this animal express high multixenobiotic resistance (MXR) and multixenobiotic transport activity that is related to the mammalian p-glycoprotein (p-gp). The high p-gp observed in mussel gills may provide the mussel protection from natural toxins in the diet. To test this

N. Eufemia; S. Clerte; S. Girshick; D. Epel

2002-01-01

213

Stable isotope fractionation to investigate natural transformation mechanisms of organic contaminants: principles, prospects and limitations.  

PubMed

Gas chromatography-isotope ratio mass spectrometry (GC-IRMS) has made it possible to analyze natural stable isotope ratios (e.g., (13)C/(12)C, (15)N/(14)N, (2)H/(1)H) of individual organic contaminants in environmental samples. They may be used as fingerprints to infer contamination sources, and may demonstrate, and even quantify, the occurrence of natural contaminant transformation by the enrichment of heavy isotopes that arises from degradation-induced isotope fractionation. This review highlights an additional powerful feature of stable isotope fractionation: the study of environmental transformation mechanisms. Isotope effects reflect the energy difference of isotopologues (i.e., molecules carrying a light versus a heavy isotope in a particular molecular position) when moving from reactant to transition state. Measuring isotope fractionation, therefore, essentially allows a glimpse at transition states! It is shown how such position-specific isotope effects are "diluted out" in the compound average measured by GC-IRMS, and how a careful evaluation in mechanistic scenarios and by dual isotope plots can recover the underlying mechanistic information. The mathematical framework for multistep isotope fractionation in environmental transformations is reviewed. Case studies demonstrate how isotope fractionation changes in the presence of mass transfer, enzymatic commitment to catalysis, multiple chemical reaction steps or limited bioavailability, and how this gives information about the individual process steps. Finally, it is discussed how isotope ratios of individual products evolve in sequential or parallel transformations, and what mechanistic insight they contain. A concluding session gives an outlook on current developments, future research directions and the potential for bridging the gap between laboratory and real world systems. PMID:21038038

Elsner, Martin

2010-11-01

214

Preparation, characterization, and cation exchange selectivity of synthetic and topotactically altered naturally occurring trioctahedral micas  

NASA Astrophysics Data System (ADS)

The large quantity of high level nuclear waste held in underground stainless steel storage tanks around the country has necessitated the need for inorganic ion exchange materials with the ability to selectively remove radioactive species such as 137Cs and 90Sr in the presence of large concentrations of competing cations. Sodium expandable micas, such as sodium fluorophlogopite and K-depleted phlogopite have shown promise for this purpose. During this research highly charged sodium fluorophlogopite micas, Nax(Mg3)[AlxSi4-x]O 10F2yH2O, with layer charges of -2, -3, and -4 per unit cell were synthesized from a dry mix of poorly crystalline kaolinite, Mg(NO3)2, and NaF. Additional silicon was also added to the reaction mixture in the form of amorphous SiO2 to increase the Si:Al ratio as needed. Talc was also utilized for the first time as Si and Mg sources in the synthesis of Na-2-mica. Potassium-depleted phlogopite, K1-xNax(Mg3)[AlSi3]O 10(OH)2, was prepared by conventional and microwave assisted equilibration of <45mum phlogopite mica with a solution containing sodium tetraphenylborate. The synthesized materials were characterized using X-ray diffraction, scanning electron microscopy, magic angle spinning nuclear magnetic resonance, and wet chemical techniques. Three synthetic sodium fluorophlogopite micas and one K-depleted phlogopite sample were selected for ion exchange studies. Ion exchange isotherms for the synthetic sodium fluorophlogopite micas were obtained for Cs+, Sr2+, Ba2+, and Co2+. For the K-depleted phlogopite ion exchange isotherms for Cs+ and Sr2+ were determined. The ion exchange studies indicated that only the Na-2-mica was selective for Cs+, all three micas were selective for Sr2+. All three mica also appeared to be highly selective for both Ba2+ and Co2+. The ion exchange studies indicated that the K-depleted phlogopite was highly selective for both Cs+ and Sr 2+. The ion selectivity of all of these micas indicates that they may be useful not only for removal of radioactive isotopes from the nuclear waste stream, but also removal of transition metal cations from industrial wastes.

Stout, Stephen Anthony

215

Introduction to chemistry and applications in nature of mass independent isotope effects special feature.  

PubMed

Stable isotope ratio variations are regulated by physical and chemical laws. These rules depend on a relation with mass differences between isotopes. New classes of isotope variation effects that deviate from mass dependent laws, termed mass independent isotope effects, were discovered in 1983 and have a wide range of applications in basic chemistry and nature. In this special edition, new applications of these effects to physical chemistry, solar system origin models, terrestrial atmospheric and biogenic evolution, polar paleo climatology, snowball earth geology, and present day atmospheric sciences are presented. PMID:24167299

Thiemens, Mark H

2013-10-29

216

Introduction to Chemistry and Applications in Nature of Mass Independent Isotope Effects Special Feature  

PubMed Central

Stable isotope ratio variations are regulated by physical and chemical laws. These rules depend on a relation with mass differences between isotopes. New classes of isotope variation effects that deviate from mass dependent laws, termed mass independent isotope effects, were discovered in 1983 and have a wide range of applications in basic chemistry and nature. In this special edition, new applications of these effects to physical chemistry, solar system origin models, terrestrial atmospheric and biogenic evolution, polar paleo climatology, snowball earth geology, and present day atmospheric sciences are presented. PMID:24167299

Thiemens, Mark H.

2013-01-01

217

When a natural disaster occurs: lessons learned in meeting students' needs.  

PubMed

Across the nation, weather-related natural disasters-tropical storms, floods, tornadoes, and earthquakes-struck even areas where weather concerns are not paramount on the minds of most people. These natural disasters heightened awareness that all geographic areas are susceptible to aberrant weather conditions. The purpose of this article was to relate the lessons learned by one academic health center in meeting students' emergency preparedness and disaster recovery needs following a major hurricane in fall 2008. To gauge students' storm-related needs, a Hurricane Needs Survey (HNS) was conducted in spring 2009, 7 months after the hurricane. Students responded to 26 structured response items and 3 open-ended questions. Five hundred fifteen surveys were completed, constituting a response rate of 37.2%. Data were analyzed by creating frequencies to profile students' hurricane experiences. Results indicated that all students left the island under mandatory evacuation orders; most stayed with their families, and most experienced moderate material losses. For some students, the evacuation process and life after the storm contributed to ongoing problems, worries, and academic performance issues. Qualitative content analysis was used to derive themes from the students' narrative responses to the HNS open-ended questions about their perceptions of the extent to which the University of Texas Medical Branch met their needs. When students' hurricane response comments were analyzed, three major themes emerged: being prepared, needing to be connected, and returning to normalcy. The major lessons learned are that the emergency preparation of students requires greater specificity and that discussion about poststorm recovery expectations is essential. Following a natural disaster, students experience more distress than may be readily apparent. PMID:22142912

Watson, Pamela G; Loffredo, Vincent J; McKee, John C

2011-01-01

218

Synthesis and biological evaluation of isomeric derivatives of naturally occurring spatozoate.  

PubMed

An isomer of the natural phthalate ester spatozoate (1), n-butyl 2-benzoyloxymethylbenzoate (2a) and a series of its new derivatives 2b-2s were synthesized and exposed to selected biological screening, as phthalates were reported to possess different biological activities. Compound 2g was found to be the most potent cytotoxic agent with a LD50 = 8.98 microg/ml. In a bactericidal assay the compounds showed a broad spectrum of activities. Compound 2a has a very promising fungicidal activity against Microsporum canis. PMID:16821646

Hayat, Safdar; Atta-ur-Rahman; Choudhary, Muhammad Iqbal; Khan, Khalid Mohammed; Perveen, Shahnaz; Shah, Syed Tasadaque Ali; Anwar, Awais; Anwar, M Usman; Bayer, Ernst; Voelter, Wolfgang

2006-01-01

219

The naturally occurring carcinogen ptaquiloside is present in groundwater below bracken vegetation.  

PubMed

The present study demonstrates unequivocally the presence of the natural carcinogen ptaquiloside and its transformation product pterosin B in groundwater and surface water. Groundwater concentrations up to 0.23 nmol/L (92?ng/L) ptaquiloside and up to 2.2 nmol/L (0.47?g/L) pterosin B were found. Of 21 groundwater samples, 5 contained ptaquiloside, exceeding the estimated threshold for drinking water (1.3-40?pmol/L). The results are critical for water abstraction in bracken-infested areas. PMID:24464773

Clauson-Kaas, Frederik; Jensen, Pia H; Jacobsen, Ole S; Juhler, Ren K; Hansen, Hans Christian B

2014-05-01

220

Characterization of calcium isotopes in natural and synthetic barite  

USGS Publications Warehouse

The mineral barite (BaSO4) accommodates calcium in its crystal lattice, providing an archive of Ca-isotopes in the highly stable sulfate mineral. Holocene marine (pelagic) barite samples from the major ocean basins are isotopically indistinguishable from each other (??44/40Ca = -2.01 ?? 0.15???) but are different from hydrothermal and cold seep barite samples (??44/40Ca = -4.13 to -2.72???). Laboratory precipitated (synthetic) barite samples are more depleted in the heavy Ca-isotopes than pelagic marine barite and span a range of Ca-isotope compositions, ??44/40Ca = -3.42 to -2.40???. Temperature, saturation state, a Ba2 + / a SO42 -, and aCa2+/aBa2+ each influence the fractionation of Ca-isotopes in synthetic barite; however, the fractionation in marine barite samples is not strongly related to any measured environmental parameter. First-principles lattice dynamical modeling predicts that at equilibrium Ca-substituted barite will have much lower 44Ca/40Ca than calcite, by -9??? at 0 ??C and -8??? at 25 ??C. Based on this model, none of the measured barite samples appear to be in isotopic equilibrium with their parent solutions, although as predicted they do record lower ??44/40Ca values than seawater and calcite. Kinetic fractionation processes therefore most likely control the extent of isotopic fractionation exhibited in barite. Potential fractionation mechanisms include factors influencing Ca2+ substitution for Ba2+ in barite (e.g. ionic strength and trace element concentration of the solution, competing complexation reactions, precipitation or growth rate, temperature, pressure, and saturation state) as well as nucleation and crystal growth rates. These factors should be considered when investigating controls on isotopic fractionation of Ca2+ and other elements in inorganic and biogenic minerals. ?? 2008 Elsevier Ltd.

Griffith, E.M.; Schauble, E.A.; Bullen, T.D.; Paytan, A.

2008-01-01

221

Recruiting Older Adults into a Physical Activity Promotion Program: "Active Living Every Day" Offered in a Naturally Occurring Retirement Community  

ERIC Educational Resources Information Center

Purpose: This article explores recruitment strategies based on the transtheoretical model (TTM) with older adults living in a naturally occurring retirement community (NORC) to encourage enrollment in a physical activity promotion program, "Active Living Every Day" (ALED). Reasons for participation or nonparticipation are identified. Design and

Hildebrand, Mary; Neufeld, Peggy

2009-01-01

222

Elevated Appraisals of the Negative Impact of Naturally Occurring Life Events: A Risk Factor for Depressive and Anxiety Disorders  

ERIC Educational Resources Information Center

The tendency to appraise naturally occurring life events (LEs) as having high negative impact may be a predisposing factor for the development of depression and anxiety disorders. In the current study, appraisals of the negative impact of recent LEs were examined in relationship to depressive and anxiety disorders in a sample of 653 adolescents

Espejo, Emmanuel Peter; Hammen, Constance; Brennan, Patricia A.

2012-01-01

223

Crime and Fire Log Nature Case No. Date/Time Reported Date/Time Occurred Location Disposition  

E-print Network

Crime and Fire Log Nature Case No. Date/Time Reported Date/Time Occurred Location Disposition:00 Building 3 - 1 North Inactive 12/25/2011 Juvenile Curfew 11-1406 12/22/2011 23:18 12/22/2011 23:52 - 12

Loudon, Catherine

224

Inorganic arsenic (InAs) occurs naturally in the groundwater of many parts of the world, and  

E-print Network

Inorganic arsenic (InAs) occurs naturally in the groundwater of many parts of the world 2002). Ingested arsenic causes cancers of the skin, bladder, and lung and has been associated that are about 30­3,000 times lower (Smith et al. 2002). Importantly, the new U.S. standard for arsenic applies

California at Berkeley, University of

225

Functional Characterization of Naturally Occurring Variants of Human Hepatitis B Virus Containing the Core Internal Deletion Mutation  

Microsoft Academic Search

Naturally occurring variants of human hepatitis B virus (HBV) containing the core internal deletion (CID) mutation have been found frequently in HBV carriers worldwide. Despite numerous sequence analysis reports of CID variants in patients, in the past decade, CID variants have not been characterized functionally, and thus their biological significance to HBV infection remains unclear. We report here two different

THOMAS TA-TUNG YUAN; MIN-HUI LIN; SUI MIN QIU; CHIAHO SHIH

1998-01-01

226

Fuzzy rule-based modelling for human health risk from naturally occurring radioactive materials in produced water  

Microsoft Academic Search

Produced water, discharged from offshore oil and gas operations, contains chemicals from formation water, condensed water, and any chemical added down hole or during the oil\\/water separation process. Although, most of the contaminants fall below the detection limits within a short distance from the discharge port, a few of the remaining contaminants including naturally occurring radioactive materials (NORM) are of

Chowdhury Shakhawat; Husain Tahir; Bose Neil

2006-01-01

227

CO capture from simulated syngas via cyclic carbonation\\/calcination for a naturally occurring limestone: pilot-plant testing  

Microsoft Academic Search

Experiments were performed using a dual fluidized bed reactor system, operated in a batch mode, in order to investigate the effects of steam and simulated syngas on CO capture and sorbent conversion efficiency for a naturally occurring Polish calcitic limestone. In addition, the effect of high partial pressures of CO on the calcination process was examined using either oxygen-enriched air

R. T. Symonds; D. Y. Lu; R. W. Hughes; E. J. Anthony; A. Macchi

2009-01-01

228

The modeling of carbon isotope kinetics and its application to the evaluation of natural gas  

Microsoft Academic Search

The modeling of carbon isotope kinetics of natural gas is an issue driving pioneering research in the oil and gas geochemistry\\u000a in China and internationally. Combined with the sedimentary burial history and basin geothermal history, the modeling of carbon\\u000a isotope kinetics provides a new and effective means for the determination of the origin and accumulation history of natural\\u000a gas pools.

Xianqing LI; Xianming Xiao; Yongchun Tang; Hui Tian; Qiang Zhou; Yunfeng Yang; Peng Dong; Yan Wang; Zhihong Song

2008-01-01

229

Identification and Clinical Relevance of Naturally Occurring Human CD8+HLA-DR+ Regulatory T Cells.  

PubMed

The lack of responsiveness to self and non-self Ags is normally maintained by multiple mechanisms, including the suppressive activities of several T cell subsets. In this study, we show that CD8(+) T cells from both adult peripheral blood and umbilical cord blood mononuclear cells constitutively expressing HLA-DR represent a natural human CD8(+) regulatory T cell subset. Their suppressive effect appears to be cell-to-cell contact dependent and may involve CTLA-4 signaling between neighboring T cells. These regulatory T cells can be expanded in vitro and exhibit a suppressive capacity similar to that observed in ex vivo CD8(+)HLA-DR(+) T cells. The high frequency of CD8(+)HLA-DR(+) T cells that we detected in patients with non-small cell lung cancer deserves further work to confirm their putative suppressor effect within the tumor. PMID:25261474

Arruvito, Lourdes; Payaslin, Florencia; Baz, Plcida; Podhorzer, Ariel; Billordo, Ariel; Pandolfi, Julieta; Semeniuk, Guillermo; Arribalzaga, Eduardo; Fainboim, Leonardo

2014-11-01

230

A novel replicon occurring naturally in Escherichia coli is a phage-plasmid hybrid.  

PubMed Central

A novel DNA replicon in Escherichia coli was identified. It is the smallest natural isolate (1282 bp) found so far. In the presence of phage M13 it grows as a filamentous single-stranded DNA phage. Contrary to previously identified mini-phages this replicon displays sequence homology only to parts of the M13 viral and complementary strand origin. In the absence of M13 this DNA replicates autonomously. The only gene (arp) of the replicon encodes a 32-kd protein, which is essential for autonomous replication. The host rep gene required for replication of single-stranded DNA phages is dispensable. Distinct replication mechanisms are thus involved during growth as defective phage or as autonomous plasmid. Images PMID:3061812

Seufert, W; Lurz, R; Messer, W

1988-01-01

231

Naturally occurring radionuclides and rare earth elements in weathered Japanese soil samples  

NASA Astrophysics Data System (ADS)

The activity concentrations of 226Ra and 228Ac in weathered Japanese soils from two selected prefectures have been measured using a ?-ray spectroscopy system with high purity germanium detector. The uranium, thorium, and rare earth elements (REEs) concentrations were determined from the same soil samples using inductively coupled plasma mass spectrometry (ICP-MS). For example, granitic rocks contain higher amounts of U, Th, and light REEs compared to other igneous rocks such as basalt and andesites. Therefore, it is necessary to understand the interaction between REEs and nature of soils since soils are complex heterogeneous mixture of organic and inorganic solids, water, and gases. In this paper, we will discuss about distribution pattern of 238U and 232Th along with REEs in soil samples of weathered acid rock (granite) collected from two prefectures of Japan: Hiroshima and Miyagi.

Sahoo, Sarata K.; Hosoda, Masahiro; Prasad, Ganesh; Takahashi, Hiroyuki; Sorimachi, Atsuyuki; Ishikawa, Tetsuo; Tokonami, Shinji; Uchida, Shigeo

2013-08-01

232

Estimation of the radiological background and dose assessment in areas with naturally occurring uranium geochemical anomalies--a case study in the Iberian Massif (Central Portugal).  

PubMed

Naturally occurring uranium geochemical anomalies, representative of the several thousand recognized in the Portuguese section of the Iberian Massif and outcropping in three target areas with a total of a few thousand square metres, were subjected to a detailed study (1:1000 scale) to evaluate the radiological health-risk on the basis of a dose assessment. To reach this goal some radioactive isotopes from the uranium, thorium and potassium radioactive series were measured in 52 samples taken from different environmental compartments: soils, stream sediments, water, foodstuff (vegetables) and air; external radiation was also measured through a square grid of 1010 m, with a total of 336 measurements. The results show that some radioisotopes have high activities in all the environmental compartments as well as a large variability, namely for those of the uranium decay chain, which is a common situation in the regional geological setting. Isotopic disequilibrium is also common and led to an enrichment of several isotopes in the different pathways, as is the case of (226)Ra; maximum values of 1.76 Bq L(-1) (water), 986 Bq kg(-1) (soils) and 18.9 Bq kg(-1) (in a turnip sample) were measured. On the basis of a realistic scenario combined with the experimental data, the effective dose from exposure to ionizing radiation for two groups of the population (rural and urban) was calculated; the effective dose is variable between 8.0 and 9.5 mSv year(-1), which is 3-4 times higher than the world average. Thus, the radiological health-risk for these populations could be significant and the studied uranium anomalies must be taken into account in the assessment of the geochemical background. The estimated effective dose can also be used as typical of the background of the Beiras uranium metalogenetic province and therefore as a "benchmark" in the remediation of the old uranium mining sites. PMID:22694913

Pereira, A J S C; Neves, L J P F

2012-10-01

233

Phylogeny and Virulence of Naturally Occurring Type III Secretion System-Deficient Pectobacterium Strains?  

PubMed Central

Pectobacterium species are enterobacterial plant-pathogenic bacteria that cause soft rot disease in diverse plant species. Previous epidemiological studies of Pectobacterium species have suffered from an inability to identify most isolates to the species or subspecies level. We used three previously described DNA-based methods, 16S-23S intergenic transcribed spacer PCR-restriction fragment length polymorphism analysis, multilocus sequence analysis (MLSA), and pulsed-field gel electrophoresis, to examine isolates from diseased stems and tubers and found that MLSA provided the most reliable classification of isolates. We found that strains belonging to at least two Pectobacterium clades were present in each field examined, although representatives of only three of five Pectobacterium clades were isolated. Hypersensitive response and DNA hybridization assays revealed that strains of both Pectobacterium carotovorum and Pectobacterium wasabiae lack a type III secretion system (T3SS). Two of the T3SS-deficient strains assayed lack genes adjacent to the T3SS gene cluster, suggesting that multiple deletions occurred in Pectobacterium strains in this locus, and all strains appear to have only six rRNA operons instead of the seven operons typically found in Pectobacterium strains. The virulence of most of the T3SS-deficient strains was similar to that of T3SS-encoding strains in stems and tubers. PMID:19411432

Kim, Hye-Sook; Ma, Bing; Perna, Nicole T.; Charkowski, Amy O.

2009-01-01

234

Hidden localization motifs: naturally occurring peroxisomal targeting signals in non-peroxisomal proteins  

PubMed Central

Background Can sequence segments coding for subcellular targeting or for posttranslational modifications occur in proteins that are not substrates in either of these processes? Although considerable effort has been invested in achieving low false-positive prediction rates, even accurate sequence-analysis tools for the recognition of these motifs generate a small but noticeable number of protein hits that lack the appropriate biological context but cannot be rationalized as false positives. Results We show that the carboxyl termini of a set of definitely non-peroxisomal proteins with predicted peroxisomal targeting signals interact with the peroxisomal matrix protein receptor peroxin 5 (PEX5) in a yeast two-hybrid test. Moreover, we show that examples of these proteins - chicken lysozyme, human tyrosinase and the yeast mitochondrial ribosomal protein L2 (encoded by MRP7) - are imported into peroxisomes in vivo if their original sorting signals are disguised. We also show that even prokaryotic proteins can contain peroxisomal targeting sequences. Conclusions Thus, functional localization signals can evolve in unrelated protein sequences as a result of neutral mutations, and subcellular targeting is hierarchically organized, with signal accessibility playing a decisive role. The occurrence of silent functional motifs in unrelated proteins is important for the development of sequence-based function prediction tools and the interpretation of their results. Silent functional signals have the potential to acquire importance in future evolutionary scenarios and in pathological conditions. PMID:15575971

Neuberger, Georg; Kunze, Markus; Eisenhaber, Frank; Berger, Johannes; Hartig, Andreas; Brocard, Cecile

2004-01-01

235

Diagnostic features in 10 naturally occurring cases of acute fatal canine leptospirosis.  

PubMed

The current report describes the diagnostic features in 10 cases of acute fatal canine leptospirosis with minimal renal and hepatic changes that may present a diagnostic challenge for the pathologist. Most affected dogs were less than 6 months of age and had a biochemical profile consistent with hepatorenal dysfunction. Clinical signs consisted of vomiting, depression, icterus, dehydration, diarrhea, and anorexia. All dogs died or were humanely euthanized within 3-7 days after the onset of clinical disease. Necropsy findings included pulmonary edema with hemorrhages, icterus, renal and hepatic pallor and swelling, and gastric edema with hemorrhage. Despite severe azotemia, histological changes in the kidneys were subtle in all dogs, and included mild renal tubular simplification, with single-cell necrosis and attenuation, along with minimal interstitial lymphoplasmacytic inflammation, edema, and hemorrhage. Hepatic lesions included scattered hepatocellular single-cell necrosis and hepatocellular dissociation. Prominent extrarenal lesions typically associated with uremia including vascular fibrinoid necrosis in multiple organs, pulmonary mineralization with occasional fibrinosuppurative exudation, and gastric mineralization were also present. Postmortem diagnostic confirmation was based on the detection of leptospiral antigen on fresh renal samples by fluorescent antibody test and on the demonstration of intact spirochetes in sections of kidneys using immunohistochemical staining. Acute fatal canine leptospirosis occurred as a fulminant hepatorenal disease affecting mainly young dogs, and the diagnosis was dependent on the recognition of the subtle renal changes with confirmation via fluorescent antibody testing or immunohistochemical staining. PMID:25274745

Rissi, Daniel R; Brown, Cathy A

2014-11-01

236

Temporal alignment between head gesture and prosodic prominence in naturally occurring conversation: An electromagnetic articulometry study.  

PubMed

Studies of the relationship between speech events and gesticulation have suggested that the peak of the prosodic pitch accent serves as a target with which body gestures may be coordinated (Roth, 2002; Loehr, 2004). While previous work has relied on controlled speech elicitation generally restricted to nonrepresentational extension/retraction (Leonard and Cummins, 2011) or iconic (Kelly et al., 2008) gestures, here we examine the kinematics of the speech articulators and associated head movements from pairs of individuals engaged in spontaneous conversation. Age and gender matched native speakers of American English seated 2 m apart were recorded using two electromagnetic articulometer (EMA) devices (Tiede and Mooshammer, 2013). Head movements were characterized by the centroid of reference sensors placed on the left and right mastoid processes and the upper incisors. Pitch accents were coded following the ToBI implementation of Pierrehumbert's intonational framework following Beckman and Elam (1997). Preliminary findings show that the apex (point of maximum excursion) of head movements within an IP in general precedes the peak of the associated pitch accent, and is consistently aligned with co-occurring articulatory events within the syllable. [Work supported by NIH NIDCD-DC-012350.]. PMID:25235595

Goldenberg, Dolly; Tiede, Mark; Honorof, Douglas N; Mooshammer, Christine

2014-04-01

237

Naturally occurring genetic transfer of hydrogen-oxidizing ability between strains of Alcaligenes eutrophus.  

PubMed Central

Mutants defective in chemolithoautotrophic growth (Aut-) have been isolated from Alcaligenes eutrophus strains H16, N9A, G27, and TF93. Spontaneous Aut- mutants were obtained only with strain TF93. Mutants of the other strains were selected after conventional mutagenesis or treatment with mitomycin. Most of the mutants, including the spontaneous Aut- strains, lacked hydrogenase activity (Hox-) but possessed the ability to fix carbon dioxide (Cfx+). Agar mating of A. eutrophus H16 with Hox- mutants of the various strains resulted in transconjugants which had recovered the ability to grow autotrophically and to express activity of hydrogenase as examined by enzymatic and immunochemical analysis. Transfer of hydrogen-oxidizing ability occurred in the absence of a mobilizing plasmid such as Rp4. The transfer frequency was particularly high (ca. 10(-2) per donor) when the spontaneous Hox- mutants of strain TF93 were used as recipients. These strains proved to be plasmid free, whereas donors, transconjugants, and the mutagen-treated Hox- mutants contained a large plasmid (molecular weight, 270 +/- 10 X 10(6) revealed by agarose gel electrophoresis. The results allow the conclusion that A. eutrophus H16 harbors a self-transmissible plasmid designated pHG1, which carries information for hydrogen-oxidizing ability. Images PMID:6787025

Friedrich, B; Hogrefe, C; Schlegel, H G

1981-01-01

238

Sulphoraphane, a naturally occurring isothiocyanate induces apoptosis in breast cancer cells by targeting heat shock proteins  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer HSPs (27, 70 and 90) and HSF1 are overexpressed in MCF-7 and MDA-MB-231 cells. Black-Right-Pointing-Pointer Sulphoraphane, a natural isothiocyanate inhibited HSPs and HSF1 expressions. Black-Right-Pointing-Pointer Inhibition of HSPs and HSF1 lead to regulation of apoptotic proteins. Black-Right-Pointing-Pointer Alteration of apoptotic proteins activate of caspases particularly caspase 3 and 9 leading to induction of apoptosis. Black-Right-Pointing-Pointer Alteration of apoptotic proteins induce caspases leading to induction of apoptosis. -- Abstract: Heat shock proteins (HSPs) are involved in protein folding, aggregation, transport and/or stabilization by acting as a molecular chaperone, leading to inhibition of apoptosis by both caspase dependent and/or independent pathways. HSPs are overexpressed in a wide range of human cancers and are implicated in tumor cell proliferation, differentiation, invasion and metastasis. HSPs particularly 27, 70, 90 and the transcription factor heat shock factor1 (HSF1) play key roles in the etiology of breast cancer and can be considered as potential therapeutic target. The present study was designed to investigate the role of sulphoraphane, a natural isothiocyanate on HSPs (27, 70, 90) and HSF1 in two different breast cancer cell lines MCF-7 and MDA-MB-231 cells expressing wild type and mutated p53 respectively, vis-a-vis in normal breast epithelial cell line MCF-12F. It was furthermore investigated whether modulation of HSPs and HSF1 could induce apoptosis in these cells by altering the expressions of p53, p21 and some apoptotic proteins like Bcl-2, Bax, Bid, Bad, Apaf-1 and AIF. Sulphoraphane was found to down-regulate the expressions of HSP70, 90 and HSF1, though the effect on HSP27 was not pronounced. Consequences of HSP inhibition was upregulation of p21 irrespective of p53 status. Bax, Bad, Apaf-1, AIF were upregulated followed by down-regulation of Bcl-2 and this effect was prominent in MCF-7 than in MDA-MB-231. However, very little change in the expression of Bid was observed. Alteration in Bcl-2 Bax ratio resulted in the release of cytochrome c from mitochondria and activation of caspases 3 and 9 which are in agreement with apoptotic index values. Sulphoraphane therefore can be regarded as a potent inducer of apoptosis due to HSP modulation in breast cancer cells.

Sarkar, Ruma; Mukherjee, Sutapa [Department of Environmental Carcinogenesis and Toxicology, Chittaranjan National Cancer Institute, 37, SP Mukherjee Road, Kolkata 700 026 (India)] [Department of Environmental Carcinogenesis and Toxicology, Chittaranjan National Cancer Institute, 37, SP Mukherjee Road, Kolkata 700 026 (India); Biswas, Jaydip [Chittaranjan National Cancer Institute, 37, SP Mukherjee Road, Kolkata 700 026 (India)] [Chittaranjan National Cancer Institute, 37, SP Mukherjee Road, Kolkata 700 026 (India); Roy, Madhumita, E-mail: mitacnci@yahoo.co.in [Department of Environmental Carcinogenesis and Toxicology, Chittaranjan National Cancer Institute, 37, SP Mukherjee Road, Kolkata 700 026 (India)] [Department of Environmental Carcinogenesis and Toxicology, Chittaranjan National Cancer Institute, 37, SP Mukherjee Road, Kolkata 700 026 (India)

2012-10-12

239

Using Natural Stable Calcium Isotopes to Rapidly Assess Changes in Bone Mineral Balance Using a Bed Rest Model to Induce Bone Loss  

NASA Technical Reports Server (NTRS)

Metabolic bone diseases like osteoporosis result from the disruption of normal bone mineral balance (BMB) resulting in bone loss. During spaceflight astronauts lose substantial bone. Bed rest provides an analog to simulate some of the effects of spaceflight; including bone and calcium loss and provides the opportunity to evaluate new methods to monitor BMB in healthy individuals undergoing environmentally induced-bone loss. Previous research showed that natural variations in the Ca isotope ratio occur because bone formation depletes soft tissue of light Ca isotopes while bone resorption releases that isotopically light Ca back into soft tissue (Skulan et al, 2007). Using a bed rest model, we demonstrate that the Ca isotope ratio of urine shifts in a direction consistent with bone loss after just 7 days of bed rest, long before detectable changes in bone mineral density (BMD) occur. The Ca isotope variations tracks changes observed in urinary N-teleopeptide, a bone resorption biomarker. Bone specific alkaline phosphatase, a bone formation biomarker, is unchanged. The established relationship between Ca isotopes and BMB can be used to quantitatively translate the changes in the Ca isotope ratio to changes in BMD using a simple mathematical model. This model predicts that subjects lost 0.25 0.07% ( SD) of their bone mass from day 7 to day 30 of bed rest. Given the rapid signal observed using Ca isotope measurements and the potential to quantitatively assess bone loss; this technique is well suited to study the short-term dynamics of bone metabolism.

Morgan, J. L. L.; Skulan, J. L.; Gordon, G. E.; Smith, Scott M.; Romaniello, S. J.; Anbar, A. D.

2012-01-01

240

Naturally occurring arsenic in sandstone aquifer water supply wells of northeastern Wisconsin  

SciTech Connect

The US Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 50 {micro}g/L for arsenic was exceeded in 86 of 2,125 water supply wells sampled over a broad geographic range in parts of Brown, Outagamie, and Winnebago Counties, Wisconsin. The hydrologic and geochemical properties of the area were examined and the source of arsenic was determined to be natural. Ground water collected from two geologic formations, the St. Peter Sandstone and the overlying Platteville/Galena Dolomite, was found to be the principal source of the elevated arsenic concentrations. These two formations supply a large portion of eastern Wisconsin private wells with their drinking water. Based on the data gathered from this study, an arsenic advisory area was designated for both Outagamie and Winnebago Counties. Guidelines were developed for well drillers and owners constructing new wells within the advisory area to reduce the likelihood of arsenic presence in the water supply. Fifteen wells containing arsenic exceeding the MCL were successfully reconstructed or new wells were constructed based on the guidelines developed. These constructions substantially reduced arsenic levels in the well water supplies.

Burkel, R.S.; Stoll, R.C.

1999-10-01

241

Radiological indices of technologically enhanced naturally occurring radionuclides: a PIXE approach.  

PubMed

This paper reports an assessment of the level of the radionuclides (40)K, (232)Th and (238)U in environmental soil samples (process waste), and hence their calculated dose rates. For this purpose, the radioactivity from three natural radionuclides was determined in tin process-waste samples in Jos, Nigeria. This work is based on the particle induced x-ray emission (PIXE) approach, devoid of the secular equilibrium, and most of the resolution, interference, self-absorption, geometrical and density correction problems inherent in gamma spectrometry. Many potential environmental hazards have been observed and the data would be of use to the government in its remediation plan for the study area. The high hazard indices require taking adequate measures to check exposures, and an underground lining in the waste ponds to prevent direct contact with the waste pile is recommended. The use of the wastes as building materials should be stopped and use of soils around this area in any development projects should be discouraged until detailed studies on indoor radiation doses and the effects on the inhabitants of prolonged exposures have been carried out. PMID:21617293

Olise, Felix Samuel; Owoade, Oyediran Kayode; Olaniyi, Hezekiah Bamidele

2011-06-01

242

Naturally Occurring Changes in Women's Drinking From High School to College and Implications for Sexual Victimization  

PubMed Central

Objective: The current study examined the natural trajectories of alcohol use among women as they transitioned from high school to college, considering changes in drinking for students at initially different levels of drinking. We examined the hypothesis that the association between college drinking and sexual victimization would be stronger for women with less high school drinking experience. Method: Female, college-bound, high school seniors were recruited from the community at the time of graduation (N = 437). Alcohol consumption and sexual victimization were assessed at the time of high school graduation (Time 0 [T0]) and at the end of the first (T1) and second (T2) semesters of college. Results: Abstainers and light drinkers increased alcohol consumption from T0 to T1; however, consumption by those already engaging in heavy episodic drinking remained stable. Consumption did not increase for any group from T1 to T2. As expected, maximum consumption in college was strongly associated with experiencing incapacitated rape or other sexual victimization during the same semester; however, prior drinking experience did not moderate the relationship. Conclusions: Occasions of heavy drinking in college are a significant risk factor for sexual victimization for both experienced and inexperienced drinkers. Findings point toward universal prevention, ideally before college entry, as a strategy for reducing heavy episodic drinking and hence, college sexual victimization. PMID:22152659

Testa, Maria; Hoffman, Joseph H.

2012-01-01

243

The isotopic effects of electron transfer: An explanation for Fe isotope fractionation in nature  

Microsoft Academic Search

Isotope fractionation of electroplated Fe was measured as a function of applied electrochemical potential. As plating voltage was varied from ?0.9 V to 2.0 V, the isotopic signature of the electroplated iron became depleted in heavy Fe, with ?56Fe values (relative to IRMM-14) ranging from ?0.18(0.02) to ?2.290(0.006) , and corresponding ?57Fe values of ?0.247(0.014) and ?3.354(0.019) . This study

Abby Kavner; Franois Bonet; Anat Shahar; Justin Simon; Edward Young

2005-01-01

244

Cloning and expression of pig kidney dopa decarboxylase: comparison of the naturally occurring and recombinant enzymes.  

PubMed Central

L-Aromatic amino acid decarboxylase (dopa decarboxylase; DDC) is a pyridoxal 5'-phosphate (PLP)-dependent homodimeric enzyme that catalyses the decarboxylation of L-dopa and other L-aromatic amino acids. To advance structure-function studies with the enzyme, a cDNA that codes for the protein from pig kidney has been cloned by joining a partial cDNA obtained by library screening with a synthetic portion constructed by the annealing and extension of long oligonucleotides. The hybrid cDNA was then expressed in Escherichia coli to produce recombinant protein. During characterization of the recombinant enzyme it was unexpectedly observed that it possesses certain differences from the enzyme purified from pig kidney. Whereas the later protein binds 1 molecule of PLP per dimer, the recombinant enzyme was found to bind two molecules of coenzyme per dimer. Moreover, the Vmax was twice that of the protein purified from tissue. On addition of substrate, the absorbance changes accompanying transaldimination were likewise 2-fold greater in the recombinant enzyme. Examination of the respective apoenzymes by absorbance, CD and fluorescence spectroscopy revealed distinct differences. The recombinant apoprotein has no significant absorbance at 335 nm, unlike the pig kidney apoenzyme; in the latter case this residual absorbance is associated with a positive dichroic signal. When excited at 335 nm the pig kidney apoenzyme has a pronounced emission maximum at 385 nm, in contrast with its recombinant counterpart, which shows a weak broad emission at about 400 nm. However, the holoenzyme-apoenzyme transition did not markedly alter the respective fluorescence properties of either recombinant or pig kidney DDC when excited at 335 nm. Taken together, these findings indicate that recombinant pig kidney DDC has two active-site PLP molecules and therefore displays structural characteristics typical of PLP-dependent homodimeric enzymes. The natural enzyme contains one active-site PLP molecule whereas the remaining PLP binding site is most probably occupied by an inactive covalently bound coenzyme derivative; some speculations are made about its origin. The coenzyme absorbing bands of recombinant DDC show a modest pH dependence at 335 and 425 nm. A putative working model is presented to explain this behaviour. PMID:8670114

Moore, P S; Dominici, P; Borri Voltattorni, C

1996-01-01

245

Naturally occurring and stress induced tubular structures from mammalian cells, a survival mechanism  

PubMed Central

Background Tubular shaped mammalian cells in response to dehydration have not been previously reported. This may be due to the invisibility of these cells in aqueous solution, and because sugars and salts added to the cell culture for manipulation of the osmotic conditions inhibit transformation of normal cells into tubular shaped structures. Results We report the transformation of normal spherical mammalian cells into tubular shaped structures in response to stress. We have termed these transformed structures 'straw cells' which we have associated with a variety of human tissue types, including fresh, post mortem and frozen lung, liver, skin, and heart. We have also documented the presence of straw cells in bovine brain and prostate tissues of mice. The number of straw cells in heart, lung tissues, and collapsed straw cells in urine increases with the age of the mammal. Straw cells were also reproduced in vitro from human cancer cells (THP1, CACO2, and MCF7) and mouse stem cells (D1 and adipose D1) by dehydrating cultured cells. The tubular center of the straw cells is much smaller than the original cell; houses condensed organelles and have filamentous extensions that are covered with microscopic hair-like structures and circular openings. When rehydrated, the filaments uptake water rapidly. The straw cell walls, have a range of 120 nm to 200 nm and are composed of sulfated-glucose polymers and glycosylated acidic proteins. The transformation from normal cell to straw cells takes 5 to 8 hr in open-air. This process is characterized by an increase in metabolic activity. When rehydrated, the straw cells regain their normal spherical shape and begin to divide in 10 to 15 days. Like various types of microbial spores, straw cells are resistant to harsh environmental conditions such as UV-C radiation. Conclusion Straw cells are specialized cellular structures and not artifacts from spontaneous polymerization, which are generated in response to stress conditions, like dehydration. The disintegrative, mobile, disruptive and ubiquitous nature of straw cells makes this a possible physiological process that may be involved in human health, longevity, and various types of diseases such as cancer. PMID:17705822

Wu, Yonnie; Laughlin, Richard C; Henry, David C; Krueger, Darryl E; Hudson, JoAn S; Kuan, Cheng-Yi; He, Jian; Reppert, Jason; Tomkins, Jeffrey P

2007-01-01

246

Nuclear genomic control of naturally occurring variation in mitochondrial function in Drosophila melanogaster  

PubMed Central

Background Mitochondria are organelles found in nearly all eukaryotic cells that play a crucial role in cellular survival and function. Mitochondrial function is under the control of nuclear and mitochondrial genomes. While the latter has been the focus of most genetic research, we remain largely ignorant about the nuclear-encoded genomic control of inter-individual variability in mitochondrial function. Here, we used Drosophila melanogaster as our model organism to address this question. Results We quantified mitochondrial state 3 and state 4 respiration rates and P:O ratio in mitochondria isolated from the thoraces of 40 sequenced inbred lines of the Drosophila Genetic Reference Panel. We found significant within-population genetic variability for all mitochondrial traits. Hence, we performed genome-wide association mapping and identified 141 single nucleotide polymorphisms (SNPs) associated with differences in mitochondrial respiration and efficiency (P ?1??10-5). Gene-centered regression models showed that 23 SNPs can explain 31, 13, and 18% of the phenotypic variation in state 3, state 4, and P:O ratio, respectively. Most of the genes tagged by the SNPs are involved in organ development, second messenger-mediated signaling pathways, and cytoskeleton remodeling. One of these genes, sallimus (sls), encodes a component of the muscle sarcomere. We confirmed the direct effect of sls on mitochondrial respiration using two viable mutants and their coisogenic wild-type strain. Furthermore, correlation network analysis revealed that sls functions as a transcriptional hub in a co-regulated module associated with mitochondrial respiration and is connected to CG7834, which is predicted to encode a protein with mitochondrial electron transfer flavoprotein activity. This latter finding was also verified in the sls mutants. Conclusions Our results provide novel insights into the genetic factors regulating natural variation in mitochondrial function in D. melanogaster. The integrative genomic approach used in our study allowed us to identify sls as a novel hub gene responsible for the regulation of mitochondrial respiration in muscle sarcomere and to provide evidence that sls might act via the electron transfer flavoprotein/ubiquinone oxidoreductase complex. PMID:23171078

2012-01-01

247

Determination of naturally-occurring actinides and their progeny in fresh water using ICP-MS and batch separation  

SciTech Connect

The determination of naturally-occurring actinides (including progeny such as {sup 230}Th) in fresh water is of significance in limnology, hydrology, and environmental monitoring. In many instances, these determinations require multiple analyses and a combination of radiometric and elemental measurement techniques (e.g., alpha spectrometry and thermal ionization mass spectrometry). In this work, we will describe the use of a single technique, inductively coupled plasma-mass spectrometry (ICP-MS), for these determinations. We will also describe the batch separation chemistry used to facilitate these determinations in ground and surface water, where natural analyte concentrations run between 1 {mu}g/L and 1 {mu}g/L.

Crain, J.S.; Alvarado, J.A.; Kiely, J.T. [Argonne National Lab., IL (United States)] [and others

1995-12-01

248

Nature Macmillan Publishers Ltd 1998 ReOs isotope evidence  

E-print Network

and evolution of the crust as a whole, and the petrogenesis of continental basalts. Here we present rhenium­osmium lower continental crust8­9 . Our data indicate that the lower crust has 1 to 2 times as much osmium the rhe- nium­osmium isotope systematics to indicate that assimilation and fractional crystallization

Rudnick, Roberta L.

249

APPLICATIONS OF ENVIRONMENTAL ISOTOPES FOR WATERSHED INVESTIGATIONS  

EPA Science Inventory

Environmental isotopes include naturally-occurring nuclides that can be applied as tracers within watersheds (Sidle, 1998). Recent advances in mass spectroscopy may supplant many traditional and costly hydrometric techniques. It is now possible, for example, to utilize isotopes a...

250

The p75 Neurotrophin Receptor Mediates Neuronal Apoptosis and Is Essential for Naturally Occurring Sympathetic Neuron Death  

Microsoft Academic Search

To determine whether the p75 neurotrophin receptor (p75NTR) plays a role in naturally occurring neuronal death, we examined neonatal sympathetic neurons that express both the TrkA tyrosine kinase re- ceptor and p75NTR. When sympathetic neuron sur- vival is maintained with low quantities of NGF or KCl, the neurotrophin brain-derived neurotrophic factor (BDNF), which does not activate Trk receptors on sympathetic

Shernaz X. Bamji; Marta Majdan; Christine D. Pozniak; Daniel J. Belliveau; Raquel Aloyz; Judi Kohn; Carrie G. Causing; Freda D. Miller

1998-01-01

251

Mangiferin, a natural occurring glucosyl xanthone, increases susceptibility of rat liver mitochondria to calcium-induced permeability transition  

Microsoft Academic Search

Mitochondrial permeability transition (MPT) is a Ca2+-dependent, cyclosporine A-sensitive, non-selective inner membrane permeabilization induced by a wide range of agents or conditions, which has often been associated with necrotic or apoptotic cell death. When mitochondria isolated from livers of rats treated with the natural occurring glucosyl xanthone mangiferin (40mg\\/kg body weight) were exposed in vitro to Ca2+, they underwent CsA,

Gilberto Lzaro Pardo Andreu; Ren Delgado; Jesus Antonio Velho; Carlos Curti; Anibal E. Vercesi

2005-01-01

252

[From alert to laboratory: a coherent network designed to deal with to naturally occurring infectious disease outbreaks and bioterrorism].  

PubMed

Public health prevention requires early detection of disease outbreaks, whether naturally occurring or due to bioterrorism. Permanent surveillance and a network of laboratories are the two main pillars of effective outbreak management. Coordination of information, training, and procedures are under the responsibility of the French public health watch institute and the scientific advisory board for the Biotox-Piratox laboratory network. Protective capacities against bioterrorism are improving but efforts must continue. PMID:18402161

Binder, Patrice; Brucker, Gilles; Josseran, Loc

2007-06-01

253

Cellular targets and mechanistic strategies of remyelination-promoting IgMs as part of the naturally occurring autoantibody repertoire  

PubMed Central

Immunoglobulins with germline sequences occur in invertebrates and vertebrates and are named naturally occurring autoantibodies (NAbs). NAbs may target foreign antigens, self- or altered self-components and are part of the normal immunoglobulin repertoire. Accumulating evidence indicates that naturally occurring antibodies can act as systemic surveillance molecules, which tag, damaged or stressed cells, invading pathogens and toxic cellular debris for elimination by the immune system. In addition to acting as detecting molecules, certain types of NAbs actively signal in different cell types with a broad range of responses from induction of apoptosis in cancer cells to stimulation of remyelination in glial cells. This review emphasizes functions and characteristics of NAbs with focus on remyelination-promoting mouse and human antibodies. Human remyelination-promoting NAbs are potential therapeutics to combat a wide spectrum of disease processes including demyelinating diseases like multiple sclerosis. We will highlight the identified glycosphingolipid (SL) antigens of polyreactive remyelination-promoting antibodies and their proposed mechanism(s) of action. The nature of the identified antigens suggests a lipid raft-based mechanism for remyelination-promoting antibodies with SLs as most essential raft components. However, accumulating evidence also suggests involvement of other antigens in stimulation of remyelination, which will be discussed in the text. PMID:24053345

Watzlawik, Jens O; Wootla, Bharath; Painter, Meghan M; Warrington, Arthur E; Rodriguez, Moses

2014-01-01

254

Laccase-catalysed oxidations of naturally occurring phenols: from in vivo biosynthetic pathways to green synthetic applications  

PubMed Central

Summary Laccases are oxidases that contain several copper atoms, and catalyse single?electron oxidations of phenolic compounds with concomitant reduction of oxygen to water. The enzymes are particularly widespread in ligninolytic basidiomycetes, but also occur in certain prokaryotes, insects and plants. Depending on the species, laccases are involved in various biosynthetic processes contributing to carbon recycling in land ecosystems and the morphogenesis of biomatrices, wherein low?molecular?weight naturally occurring phenols serve as key enzyme substrates. Studies of these in vivo synthetic pathways have afforded new insights into fungal laccase applicability in green synthetic chemistry. Thus, we here review fungal laccase?catalysed oxidations of naturally occurring phenols that are particularly relevant to the synthesis of fine organic chemicals, and we discuss how the discovered synthetic strategies mimic laccase?involved in vivo pathways, thus enhancing the green nature of such reactions. Laccase?catalysed in vivo processes yield several types of biopolymers, including those of cuticles, lignin, polyflavonoids, humus and the melanin pigments, using natural mono? or poly?phenols as building blocks. The in vivo synthetic pathways involve either phenoxyl radical?mediated coupling or cross?linking reactions, and can be adapted to the design of in vitro oxidative processes involving fungal laccases in organic synthesis; the laccase substrates and the synthetic mechanisms reflect in vivo processes. Notably, such in vitro synthetic pathways can also reproduce physicochemical properties (e.g. those of chromophores, and radical?scavenging, hydration and antimicrobial activities) found in natural biomaterials. Careful study of laccase?associated in vivo metabolic pathways has been rewarded by the discovery of novel green applications for fungal laccases. This review comprehensively summarizes the available data on laccase?catalysed biosynthetic pathways and associated applications in fine chemical syntheses. PMID:21791030

Jeon, Jong-Rok; Baldrian, Petr; Murugesan, Kumarasamy; Chang, Yoon-Seok

2012-01-01

255

Prediction of rodent carcinogenic potential of naturally occurring chemicals in the human diet using high-throughput QSAR predictive modeling  

SciTech Connect

Consistent with the U.S. Food and Drug Administration (FDA) Critical Path Initiative, predictive toxicology software programs employing quantitative structure-activity relationship (QSAR) models are currently under evaluation for regulatory risk assessment and scientific decision support for highly sensitive endpoints such as carcinogenicity, mutagenicity and reproductive toxicity. At the FDA's Center for Food Safety and Applied Nutrition's Office of Food Additive Safety and the Center for Drug Evaluation and Research's Informatics and Computational Safety Analysis Staff (ICSAS), the use of computational SAR tools for both qualitative and quantitative risk assessment applications are being developed and evaluated. One tool of current interest is MDL-QSAR predictive discriminant analysis modeling of rodent carcinogenicity, which has been previously evaluated for pharmaceutical applications by the FDA ICSAS. The study described in this paper aims to evaluate the utility of this software to estimate the carcinogenic potential of small, organic, naturally occurring chemicals found in the human diet. In addition, a group of 19 known synthetic dietary constituents that were positive in rodent carcinogenicity studies served as a control group. In the test group of naturally occurring chemicals, 101 were found to be suitable for predictive modeling using this software's discriminant analysis modeling approach. Predictions performed on these compounds were compared to published experimental evidence of each compound's carcinogenic potential. Experimental evidence included relevant toxicological studies such as rodent cancer bioassays, rodent anti-carcinogenicity studies, genotoxic studies, and the presence of chemical structural alerts. Statistical indices of predictive performance were calculated to assess the utility of the predictive modeling method. Results revealed good predictive performance using this software's rodent carcinogenicity module of over 1200 chemicals, comprised primarily of pharmaceutical, industrial and some natural products developed under an FDA-MDL cooperative research and development agreement (CRADA). The predictive performance for this group of dietary natural products and the control group was 97% sensitivity and 80% concordance. Specificity was marginal at 53%. This study finds that the in silico QSAR analysis employing this software's rodent carcinogenicity database is capable of identifying the rodent carcinogenic potential of naturally occurring organic molecules found in the human diet with a high degree of sensitivity. It is the first study to demonstrate successful QSAR predictive modeling of naturally occurring carcinogens found in the human diet using an external validation test. Further test validation of this software and expansion of the training data set for dietary chemicals will help to support the future use of such QSAR methods for screening and prioritizing the risk of dietary chemicals when actual animal data are inadequate, equivocal, or absent.

Valerio, Luis G. [Division of Biotechnology and GRAS Notice Review, US Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Food Additive Safety, HFS-255, 5100 Paint Branch Parkway, College Park, MD 20740 (United States)]. E-mail: luis.valerio@FDA.HHS.gov; Arvidson, Kirk B. [Division of Food Contact Notifications, US Food and Drug Administration, Center for Food Safety and Applied Nutrition, 7Office of Food Additive Safety, HFS-255, 5100 Paint Branch Parkway, College Park, MD 20740 (United States); Chanderbhan, Ronald F. [Division of Biotechnology and GRAS Notice Review, US Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Food Additive Safety, HFS-255, 5100 Paint Branch Parkway, College Park, MD 20740 (United States); Contrera, Joseph F. [US Food and Drug Administration, Center for Drug Evaluation and Research, Office of Pharmaceutical Science, Informatics and Computational Safety Analysis Staff, Silver Spring, MD 20993 (United States)

2007-07-01

256

Natural gas constituent and carbon isotopic composition in petroliferous basins, China  

NASA Astrophysics Data System (ADS)

There are abundant gas resources in petroliferous basins of China. Large to midsize gas fields are found in Eastern, central and Western of China. However, origin, constituents and isotopic composition of natural gas in different gas fields are varied distinctly, and some present strong chemical secondary alteration and show variation both in age and space. Based on the systematic analysis of constituents and carbon isotope of a large number of gas samples, combined with the geological characteristics, this paper classifies the origins of the gases, explores the gas isotope characteristics and evolutionary regulation with the variation time and space, and further discusses the distinctive geochemistry of the gases in China. These gases are dominated by dry gas, its methane carbon isotope values range from -10 to -70, ethane from -16 to -52, propane from -13 to -43, and butane from -18 to -34. The carbon isotopes of most gases show the characteristics of humic-derived gas and crude oil cracked gas. In addition, large primary biogenic gas fields have been discovered in the Qaidam basin; inorganic-derived alkane gases have been discovered in deep of the Songliao Basin. Half of these gas fields are characterized by the alkane carbon isotope reversal in different degrees. Research indicates there are several reasons can result in carbon isotope reversal. Firstly, gas charge of different genetic types or different source in one gas reservoir may cause carbon isotope reversal. Besides, high-over mature evolution of gas can also lead to the carbon isotopic reversal of alkanes. Thirdly, secondary alteration of hydrocarbons may also result in abnormal distribution of carbon isotope, isotope transforms to unusual light and heavy.

Zhu, Guangyou; Wang, Zhengjun; Dai, Jinxing; Su, Jing

2014-02-01

257

Naturally Occurring Radionuclides of Ash Produced by Coal Combustion. The Case of the Kardia Mine in Northern Greece  

NASA Astrophysics Data System (ADS)

West Macedonia Lignite Center (WMLC), located in Northwest Greece, releases into the atmosphere about 21,400 tons/year of fly ash through the stacks of four coal fired plants. The lignite ash contains naturally occurring radionuclides, which are deposited on the WMLC basin. This work investigates the natural radioactivity of twenty six ash samples, laboratory produced from combustion of lignite, which was sampled perpendicularly to the benches of the Kardia mine. The concentrations of radionuclides 40K, 235U, 238U, 226Ra, 228Ra and 232Th, were measured spectroscopically and found round one order of magnitude as high as those of lignite. Subsequently the Radionuclide Partitioning Coefficients of radionuclides were calculated and it was found that they are higher for 232Th, 228Ra and 40K, because the latter have closer affinity with the inorganic matrix of lignite. During combustion up to one third of the naturally occurring radioisotopes escape from the solid phase into the flue gases. With comparison to relative global data, the investigated ash has been found to have relatively high radioactivity, but the emissions of the WMLC radionuclides contribute only 0.03% to the mean annual absorbed dose.

Fotakis, M.; Tsikritzis, L.; Tzimkas, N.; Kolovos, N.; Tsikritzi, R.

2008-08-01

258

Water quality in the vicinity of Mosquito Creek Lake, Trumbull County, Ohio, in relation to the chemistry of locally occurring oil, natural gas, and brine  

USGS Publications Warehouse

Environmental samples collected in the Mosquito Creek Lake area were used to characterize water quality in relation to the chemistry of locally occurring oil, natural gas, and brine and to establish baseline water quality. Mosquito Creek Lake (a manmade reservoir) and the shallow bedrock aquifers near the lake are major sources of potable water in central Trumbull County. The city of Warren relies on the lake as a sole source of potable water. Some of the lake bottom may be in direct hydraulic connection with the underlying aquifers. The city of Cortland, along the southeastern shore of the lake, relies on the Cussewago Sandstone aquifer as a sole source of potable water. This aquifer subcrops beneath the glacio-fluvial sediments that underlie the lake. Nearly all residential homes around the lake, with the exception of homes in the city of Cortland, rely on domestic supply wells as a source of potable water. Oil and natural gas exploration and production have been ongoing in the Mosquito Creek Lakearea since the discovery of the historic Mecca Oil Pool in the Mississippian Berea and Cussewago Sandstones in 1860. Since the late 1970' s, the major drilling objective and zone of production is the Lower Silurian Clinton sandstone. The oil and natural gas resources of the Mosquito Creek Lake area, including reservoir pressure, production history, and engineering and abandonment practices are described in this report. The chemical and isotopic characteristics of the historic Mecca oil and natural gas are very different than those of the Clinton sandstone oil and natural gas. Gas chromatograms show that Mecca oil samples are extensively altered by biodegradation, whereas Clinton sandstone oils are not. Extensive alteration of Mecca oil is consistent with their occurrence at very shallow depths (less than 100 ft below land surface) where microbial activity can affect their composition. Also, the carbon-isotope composition of dissolved methane gas from Berea and Cussewago Sandstone water samples indicates that the gas is microbially generated, whereas the Clinton sandstone gases are thermogenically generated. Methane gas, in addition to crude oil, occurs naturally in the shallow Berea and Cussewago Sandstone aquifers in the Mosquito Creek Lake area and concentrations of dissolved methane are significant in the city of Cortland public-supply wells and in the domestic-supply wells near the southern shore of the lake. Water associated with oil and gas in the Clinton sandstone is a brine with high concentrations of chloride. Water from the Berea and Cussewago Sandstones, however, is fresh and potable. The contrasting geochemical characteristics are important for addressing water-quality issues that relate to oil and natural gas development in the Mosquito Creek area. A reexamination of the geologic framework and results of a subsurface-gas survey show that crude oil in the historic Mecca Oil Pool probably does not seep into Mosquito Creek Lake. Environmental samples show no evidence of any measurable release of oil, gas, or brine from the deeper Clinton sandstone oil and gas wells to the shallow aquifers, the lake, or lake tributaries. Brine is not associated with the hydrocarbons in the shallow Berea-Cussewago aquifer system and therefore cannot be a source of brine contamination. A mixing diagram constructed for dissolved bromide and chloride in surface water and water-supply wells shows no demonstrable mixing of these water resources with brine from the Clinton sandstone. There is some notable salinity in surface waters; however, the water is bromide poor, and a mixing diagram indicates that some local ground waters are influenced by halite solutions, presumably derived from leaching of road salt or from septic effluent.

Barton, G.J.; Burruss, R.C.; Ryder, R.T.

1998-01-01

259

ANALYTICAL CAPABILITY - ISOTOPE HYDROLOGY LABORATORY (WATER QUALITY MANAGEMENT BRANCH, WATER SUPPLY AND WATER RESOURCES DIVISION, NRMRL)  

EPA Science Inventory

The mission of NRMRL's Water Supply and Water Resources Division's Isotope Hydrology Laboratory is to resolve environmental hydrology problems through research and application of naturally occurring isotopes. Analytical capabilities at IHL include light stable isotope radio mass...

260

Stable water isotope characterization of human and natural impacts on land-atmosphere exchanges in the Amazon Basin  

Microsoft Academic Search

Stable water isotopes have been employed as a means of challenging, validating, and improving numerical models of the Amazon Basin since the 1980s. This paper serves as an exemplar of how characterization of human and natural impacts on surface-atmosphere water exchanges could beneficially exploit stable water isotope data and simulations. Interpretations of Amazonian isotopic data and model simulations are found

K. McGuffie; A. Henderson-Sellers

2004-01-01

261

flvi-1, a common integration domain of feline leukemia virus in naturally occurring lymphomas of a particular type.  

PubMed Central

A locus in feline DNA, termed flvi-1, which may play an important role in the natural induction of lymphomas by feline leukemia virus (FeLV) was identified. Examination of a bank of 21 naturally occurring FeLV-positive feline lymphomas revealed that FeLV proviral integration occurs at flvi-1 in four independent tumors (19%). Independent integrations occurred within a 2.4-kilobase region of flvi-1, the probability of which by random chance can be estimated as 10(-16). Several lines of evidence, including sequence analysis of the long terminal repeat, demonstrated that proviruses integrated at flvi-1 are exogenously acquired and are oriented in the same transcriptional direction with respect to the locus. Molecularly cloned flvi-1 did not hybridize with probes representing several previously described proviral integration domains or with probes representing 10 oncogenes. The natural feline lymphomas examined in this study were heterogeneous with respect to tissue of origin, cell type, and number of monoclonal proviral integrations. The four tumors in which flvi-1 is interrupted were classified as members of a phenotypic subgroup containing seven lymphomas, i.e., at least four (57%) of seven lymphomas of this type contained FeLV proviral integration at flvi-1. Members of this phenotypic subgroup are non-T-cell lymphomas isolated from the spleen and contain an average of three proviruses, compared with an average of eight among all of the tumors examined. The small number of proviral integrations in tumors of this subgroup suggests that an early proviral integration event into flvi-1 can induce malignant change. Images PMID:2161948

Levesque, K S; Bonham, L; Levy, L S

1990-01-01

262

Distribution of the PBC-specific- (M2) and the naturally-occurring mitochondrial antigen- (NOMAg) systems in plants.  

PubMed Central

In previous studies it was demonstrated that antibodies in sera from patients with primary biliary cirrhosis (PBC) and their relatives can recognize two different antigen systems in the ATPase fraction prepared from beef heart mitochondria, namely the PBC-related M2- and the naturally occurring mitochondrial antigen (NOMAg)-related epitopes. Since separation of these two antigen systems could not be achieved using mammalian mitochondria, mitochondria from a wide spectrum of plants were analysed with respect to the presence of mitochondrial antigens. Mitochondria from 29 species of plants were prepared and tested by ELISA and Western blot using marker sera from patients with PBC reacting in the Western blot with M2a,b,c,d (alpha-ketoacid-dehydrogenase complex) and NOMAg-specific sera recognizing the three major epitopes epsilon, zeta, and eta at 65, 61 and 58 kD. Naturally occurring mitochondrial antibody (NOMA)-positive marker sera reacted in the ELISA with mitochondria from all plants, and the zeta/eta positive sera gave also a positive reaction at 61/58 kD in the Western blot while the epsilon epitope could not be visualized by this method. In contrast, the M2 antigen was detected preferentially in lower plants such as algae, fungi, and ferns. Analysing these data with respect to the evolution of proteins one would have to assume that the M2 antigen was lost in most higher plants or underwent some structural alterations. Furthermore, considering the fact that the M2- and the NOMAg-related epitopes could be only partially separated, i.e. there were no plant mitochondria showing only M2 but no NOMAg, one could speculate that anti-M2 antibodies are derived from the pool of naturally occurring antibodies. Images Fig. 2 PMID:1281057

Lang, P; Klein, R; Becker, E W; Berg, P A

1992-01-01

263

Subcutaneous 5-Azacitidine Treatment of Naturally Occurring Canine Urothelial Carcinoma: A Novel Epigenetic Approach to Human Urothelial Carcinoma Drug Development  

PubMed Central

Purpose We determined the efficacy, biological activity, pharmacokinetics and safety of the hypomethylating agent 5-azacitidine (Celgene Corp., Summit, New Jersey) in dogs with naturally occurring invasive urothelial carcinoma. Materials and Methods We performed a preclinical phase I trial in dogs with naturally occurring invasive urothelial carcinoma to examine once daily subcutaneous administration of 5-azacitidine in 28-day cycles at doses of 0.10 to 0.30 mg/kg per day according to 2 dose schedules, including days 1 to 5 (28-day cohort) or days 1 to 5 and 15 to 19 (14-day cohort). Clinical efficacy was assessed by serial cystosonography, radiography and cystoscopy. Urinary 5-azacitidine pharmacokinetic analysis was also done. Pretreatment and posttreatment peripheral blood mononuclear cell and invasive urothelial carcinoma DNA, respectively, was analyzed for global and gene specific [CDKN2A (p14ARF)] methylation changes. Results Enrolled in the study were 19 dogs with naturally occurring invasive urothelial carcinoma. In the 28-day cohort the maximum tolerated dose was 0.20 mg/kg per day with higher doses resulting in grade 3 or 4 neutropenia in 4 of 6 dogs. In the 14-day cohort the maximum tolerated dose was 0.10 mg/kg per day with grade 3 or 4 neutropenia seen in 2 of 3 dogs treated at higher doses. No grade 3 or 4 nonhematological toxicity was observed during either dosing schedule. Of 18 dogs evaluable for tumor response partial remission, stable disease and progressive disease were observed in 4 (22.2%), 9 (50.0%) and 4 (22.2%), respectively. Consistent 5-azacitidine levels (205 to 857 ng/ml) were detected in urine. Pretreatment and posttreatment methylation analysis revealed no significant correlation with clinical response. Conclusions Subcutaneous 5-azacitidine showed promising clinical activity in a canine invasive urothelial carcinoma model, thus meriting further development in humans with urothelial carcinoma. PMID:22099988

Hahn, Noah M.; Bonney, Patty L.; Dhawan, Deepika; Jones, David R.; Balch, Curtis; Guo, Zhongmin; Hartman-Frey, Corie; Fang, Fang; Parker, Heidi G.; Kwon, Erika M.; Ostrander, Elaine A.; Nephew, Kenneth P.; Knapp, Deborah W.

2012-01-01

264

Chemical method for nitrogen isotopic analysis of ammonium at natural abundance.  

PubMed

We report a new chemical method to determine the (15)N natural abundance (?(15)N) for ammonium (NH4(+)) in freshwater (e.g., precipitation) and soil KCl extract. This method is based on the isotopic analysis of nitrous oxide (N2O). Ammonium is initially oxidized to nitrite (NO2(-)) by hypobromite (BrO(-)) using previously established procedures. NO2(-) is then quantitatively converted into N2O by hydroxylamine (NH2OH) under strongly acid conditions. The produced N2O is analyzed by a commercially available purge and cryogenic trap system coupled to an isotope ratio mass spectrometer (PT-IRMS). On the basis of a typical analysis size of 4 mL, the standard deviation of ?(15)N measurements is less than 0.3 and often better than 0.1 (3 to 5 replicates). Compared to previous methods, the technique here has several advantages and the potential to be used as a routine method for (15)N/(14)N analysis of NH4(+): (1) substantially simplified preparation procedures and reduced preparation time particularly compared to the methods in which diffusion or distillation is involved since all reactions occur in the same vial and separation of NH4(+) from solution is not required; (2) more suitability for low volume samples including those with low N concentration, having a blank size of 0.6 to 2 nmol; (3) elimination of the use of extremely toxic reagents (e.g., HN3) and/or the use of specialized denitrifying bacterial cultures which may be impractical for many laboratories. PMID:24654992

Liu, Dongwei; Fang, Yunting; Tu, Ying; Pan, Yuepeng

2014-04-15

265

(220)Rn/(222)Rn isotope pair as a natural proxy for soil gas transport.  

PubMed

Radon (Rn) is a naturally occurring radioactive noble gas, which is ubiquitous in soil gas. Especially, its long-lived isotope (222)Rn (half-life: 3.82 d) gained widespread acceptance as a tracer for gas transport in soils, while the short-lived (220)Rn (half-life: 55.6 s) found less interest in environmental studies. However, in some cases, the application of (222)Rn as a tracer in soil gas is complex as its concentrations can be influenced by changes of the transport conditions or of the (222)Rn production of the soil material. Due to the different half-lives of (220)Rn and (222)Rn, the distances that can be traveled by the respective isotopes before decay differ significantly, with (220)Rn migrating over much shorter distances than (222)Rn. Therefore, the soil gas concentrations of (220)Rn and (222)Rn are influenced by processes on different length scales. In laboratory experiments in a sandbox, we studied the different transport behaviors of (220)Rn and (222)Rn resulting from changing the boundary conditions for diffusive transport and from inducing advective gas movements. From the results gained in the laboratory experiments, we propose the combined analysis of (220)Rn and (222)Rn to determine gas transport processes in soils. In a field study on soil gases in the cover soil of a capped landfill we applied the combined analysis of (220)Rn and (222)Rn in soil gas for the first time and showed the feasibility of this approach to characterize soil gas transport processes. PMID:24266394

Huxol, Stephan; Brennwald, Matthias S; Henneberger, Ruth; Kipfer, Rolf

2013-12-17

266

Accidental Predissociation: A Special Case of Photo-Induced Isotope Fractionation Effect and Possible Occurrence in Nature  

NASA Astrophysics Data System (ADS)

Photo-Induced Isotope Fractionation Effects (PHIFE) are known to produce isotopic frac-tionation in some photo-dissociating molecules (1-2). The PHIFE formalism is based on the Born-Oppenheimer approximation and the Reflection Principle. The isotopic fractionation arises principally from the spectral shift induced by the small difference in zero point energy between isotopologues and the contraction of the wave function due to isotopic substitution, consequently, the associated isotopic fractionations depends on the reduced mass of the isotopically substi-tuted species. The PHIFE formalism is only applicable to the molecules which undergo direct photo-dissociation that possess continuous absorption spectra. Simple molecules (N2, O2, CO) however do not follow a direct dissociation pathway and dissociate through an indirect process termed predissociation, which occurs when the molecule is excited to a quasi-bound state energetically above the dissociation continuum. The PHIFE formalism is not applicable when the absorption spectra are discrete. The assumption that the lightest isotopologues are preferentially predissociated is only valid for restricted predissociation cases. There is a special case of predissociation known as accidental predissociation (3), which takes place through an intermediate bound state in two steps (i) leakage to an intermediate bound state (coupled through spin orbit interaction) and, (ii) predissociation to a third quasi-bound state from the intermediate state. Line broadening at an accidental predissociation is a function of the magnitude of coupling matrix elements and the linewidths are strongly influenced by isotopic substitution (4). An anomalous isotopic effect in accidental predissociation was spectroscopically observed in CO (5), N2 (4) and BeH (6). We measured the isotopic fractionation for the first time in two accidental predissociating states of CO through VUV photodissociation using the 9.0.2 beamline at ALS (7-8). In light of these data, anomalous isotopic fractionations associated with accidental predissociation will be discussed for the CO and N2. These fractionations are important as VUV-photodissociation of CO and N2 have been invoked in solar nebula (self-shielding, (9-10)) to explain the observed iso-topic signatures in different solar system objects neglecting these isotope effects during photo-dissociation. References: 1. Y. L. Yung, C. E. Miller, Science 278, 1778 (1997). 2. S. Chakraborty, S. K. Bhattacharya, J. Chem. Phys. 118, 2164 (2003). 3. H. Lefebvre-Brion, R. W. Field, The Spectra and Dynamics of Diatomic Molecules. (Elsevier Academic Press, 2004). 4. A. J. Lorquet, J. C. Lorquet, Chem. Phys. Lett. 26, 138 (1974). 5. W. Ubachs, I. Velchev, P. Cacciani, J. Chem. Phys. 113, 547 (2000). 6. H. Lefebvre-Brion, R. Colin, J. Mol. Spectrosc. 65, 33 (1977). 7. S. Chakraborty, M. Ahmed, T. L. Jackson, M. H. Thiemens, Science 321, 1328 (2008). 8. S. Chakraborty, M. Ahmed, T. L. Jackson, M. H. Thiemens, Science 324, 4 (2009). 9. R. N. Clayton, Nature 415, 860 (2002). 10. J. R. Lyons, E. D. Young, Nature 435, 317 (2005).

Chakraborty, S.; Thiemens, M. H.

2009-12-01

267

Upper limits for the existence of long-lived isotopes of roentgenium in natural gold  

SciTech Connect

A sensitive search for isotopes of a superheavy element (SHE) in natural gold materials has been performed with accelerator mass spectrometry at the Vienna Environmental Research Accelerator, which is based on a 3-MV tandem accelerator. Because the most likely SHE in gold is roentgenium (Rg, Z = 111), the search concentrated on Rg isotopes. Two different mass regions were explored: (i) For the neutron-deficient isotopes {sup 261}Rg and {sup 265}Rg, abundance limits in gold of 3x10{sup -16} were reached (no events observed). This is in stark contrast to the findings of Marinov et al.[Int. J. Mod. Phys. E 18, 621 (2009)], who reported positive identification of these isotopes with inductively coupled plasma sector field mass spectrometry in the (1-10)x10{sup -10} abundance range. (ii) Theoretical models of SHEs predict a region of increased stability around the proton and neutron shell closures of Z = 114 and N = 184. We therefore investigated eight heavy Rg isotopes, {sup A}Rg, A = 289, 290, 291, 292, 293, 294, 295, and 296. For six isotopes no events were observed, setting limits also in the 10{sup -16} abundance range. For {sup 291}Rg and {sup 294}Rg we observed two and nine events, respectively, which results in an abundance in the 10{sup -15} range. However, pileup of a particularly strong background in these cases makes a positive identification as Rg isotopes--even after pileup correction--unlikely.

Dellinger, F.; Kutschera, W.; Forstner, O.; Golser, R.; Priller, A.; Steier, P.; Wallner, A.; Winkler, G. [University of Vienna, Faculty of Physics, Vienna Environmental Research Accelerator (VERA) Laboratory, Waehringer Strasse 17, A-1090 Wien (Austria)

2011-01-15

268

Natural variation of magnesium isotopes in mammal bones and teeth from two South African trophic chains  

NASA Astrophysics Data System (ADS)

Isotopic fractionations accompanying element transfer through terrestrial ecosystems have the potential to shed light on ecological interactions between primary producers and consumers, but with the exception of carbon and nitrogen this potential has barely been exploited. Here, the magnesium stable isotope composition of bones and teeth of extant mammals from Kruger National Park (KNP) and Western Cape (WC), South Africa was measured for the first time. The nature of the geological substrate proves to be a major determinant of the ecosystem isotope baseline, as indicated by the lighter magnesium isotope ratios measured in WC mammals (ranging from -1.58 to -0.79) compared to those from KNP mammals (ranging from -1.01 to -0.04). Therefore, comparisons between the isotope signatures of taxa must be restricted to a pre-defined geographic area with a homogeneous substrate. In both parks, Mg shows slight enrichment in heavier isotopes from herbivores to carnivores. Plant remains trapped in the dentition of herbivores provide direct evidence of dietary source and, when available, were measured. In KNP only, ?26Mg of plant remains is systematically lighter than the values for herbivore teeth. These results invite further exploration of the variability of Mg isotopes in vertebrate ecosystems in order to test whether magnesium, a bio-essential element present in relatively large proportions in bone and teeth apatite, may serve as an additional trophic tracer to nitrogen, which is a constituent of collagen that rapidly degrades after burial.

Martin, Jeremy E.; Vance, Derek; Balter, Vincent

2014-04-01

269

Carbon13 kinetic isotope effects in the decarbonylations of lactic acid containing 13 C at the natural abundance level  

Microsoft Academic Search

The13C kinetic isotope fractionation in the decarbonylation of lactic acid of natural isotopic composition by sulfuric acid has been studied in the temperature range of 2080C. The13C(1) isotope separation in the decarbonylation of lactic acid by concentrated sulfuric acid depends strongly on the temperature above 40C. Below this temperature the13C isotope effect in the decarbonylation of lactic acid by concentrated

M. Zielinski; G. Czarnota; H. Papiernik-Zielinska

1992-01-01

270

Ba isotopic signature for early differentiation between Cs and Ba in natural fission reactors  

NASA Astrophysics Data System (ADS)

Ba isotopic studies of the Oklo and Bangomb natural fission reactors in east Gabon provide information on the geochemical behavior of radioactive Cs ( 135Cs and 137Cs) in a geological medium. Large isotopic deviations derived from fissiogenic Ba were found in chemical leachates of the reactor uraninites. The fissiogenic Ba isotopic patterns calculated by subtracting the non-fissiogenic component are classified into three types that show different magnifications of chemical fractionation between Cs and Ba. In addition, the isotopic signatures of fissiogenic 135Ba, 137Ba and 138Ba suggest an early differentiation between Cs and Ba of less than 20 years after the production of fissiogenic Cs and Ba. On the other hand, only small excesses of 135Ba ( ? < +1.8) and/or 137Ba ( ? < +1.3) were identified in some clay samples, which might have resulted from selective adsorption of 135Cs and 137Cs that migrated from the reactors by differentiation.

Hidaka, Hiroshi; Gauthier-Lafaye, Franois

2008-08-01

271

Molecular Imprint of Exposure to Naturally Occurring Genetic Variants of Human Cytomegalovirus on the T cell Repertoire  

NASA Astrophysics Data System (ADS)

Exposure to naturally occurring variants of herpesviruses in clinical settings can have a dramatic impact on anti-viral immunity. Here we have evaluated the molecular imprint of variant peptide-MHC complexes on the T-cell repertoire during human cytomegalovirus (CMV) infection and demonstrate that primary co-infection with genetic variants of CMV was coincident with development of strain-specific T-cell immunity followed by emergence of cross-reactive virus-specific T-cells. Cross-reactive CMV-specific T cells exhibited a highly conserved public T cell repertoire, while T cells directed towards specific genetic variants displayed oligoclonal repertoires, unique to each individual. T cell recognition foot-print and pMHC-I structural analyses revealed that the cross-reactive T cells accommodate alterations in the pMHC complex with a broader foot-print focussing on the core of the peptide epitope. These findings provide novel molecular insight into how infection with naturally occurring genetic variants of persistent human herpesviruses imprints on the evolution of the anti-viral T-cell repertoire.

Smith, Corey; Gras, Stephanie; Brennan, Rebekah M.; Bird, Nicola L.; Valkenburg, Sophie A.; Twist, Kelly-Anne; Burrows, Jacqueline M.; Miles, John J.; Chambers, Daniel; Bell, Scott; Campbell, Scott; Kedzierska, Katherine; Burrows, Scott R.; Rossjohn, Jamie; Khanna, Rajiv

2014-02-01

272

A naturally-occurring histone acetyltransferase inhibitor derived from Garcinia indica impairs newly acquired and reactivated fear memories.  

PubMed

The study of the cellular and molecular mechanisms underlying the consolidation and reconsolidation of traumatic fear memories has progressed rapidly in recent years, yet few compounds have emerged that are readily useful in a clinical setting for the treatment of anxiety disorders such as post-traumatic stress disorder (PTSD). Here, we use a combination of biochemical, behavioral, and neurophysiological methods to systematically investigate the ability of garcinol, a naturally-occurring histone acetyltransferase (HAT) inhibitor derived from the rind of the fruit of the Kokum tree (Garcina indica), to disrupt the consolidation and reconsolidation of Pavlovian fear conditioning, a widely studied rodent model of PTSD. We show that local infusion of garcinol into the rat lateral amygdala (LA) impairs the training and retrieval-related acetylation of histone H3 in the LA. Further, we show that either intra-LA or systemic administration of garcinol within a narrow window after either fear conditioning or fear memory retrieval significantly impairs the consolidation and reconsolidation of a Pavlovian fear memory and associated neural plasticity in the LA. Our findings suggest that a naturally-occurring compound derived from the diet that regulates chromatin function may be useful in the treatment of newly acquired or recently reactivated traumatic memories. PMID:23349897

Maddox, Stephanie A; Watts, Casey S; Doyre, Valrie; Schafe, Glenn E

2013-01-01

273

Association of naturally occurring radionuclides in sludges from Drinking Water Treatment Plants previously optimized for their removal.  

PubMed

The raw water used in Drinking Water Treatment Plants (DWTPs) can present high values of naturally occurring radionuclides. In order to reduce this content, the routine working conditions of DWTPs were successfully modified. This meant that those radionuclides were accumulated in the sludges generated, whose radioactive content was frequently above the exemption levels. It therefore becomes necessary to assess the association of naturally occurring radionuclides in the sludges for their potential use as agricultural fertilizers. Two approaches were studied: (a) the effect of different sequential extraction methods applied to a selected sludge; and (b) the effect of the different contents of inorganic complexes dissolved in the input water on the composition of the sludges generated by two DWTPs with different origins of their input water. Uranium and radium were mainly associated with the carbonated and reducible fractions, while (210)Po and (228)Th were associated with the residual fraction. There were differences between the two speciation methods, but the order of bioavailable radionuclides was roughly the same: (226)Ra?(234,238)U>(228)Th>(210)Po. The major inorganic complexes content, mainly carbonate, in the raw water affected the radionuclide association. The greater the carbonate content in the raw water, the greater was the association of uranium and radium with the carbonated and easily reducible fractions. PMID:24238776

Baeza, A; Salas, A; Guilln, J; Muoz-Serrano, A

2014-02-01

274

Dual Infection and Superinfection Inhibition of Epithelial Skin Cells by Two Alphaherpesviruses Co-Occur in the Natural Host  

PubMed Central

Hosts can be infected with multiple herpesviruses, known as superinfection; however, superinfection of cells is rare due to the phenomenon known as superinfection inhibition. It is believed that dual infection of cells occurs in nature, based on studies examining genetic exchange between homologous alphaherpesviruses in the host, but to date, this has not been directly shown in a natural model. In this report, gallid herpesvirus 2 (GaHV-2), better known as Mareks disease virus (MDV), was used in its natural host, the chicken, to determine whether two homologous alphaherpesviruses can infect the same cells in vivo. MDV shares close similarities with the human alphaherpesvirus, varicella zoster virus (VZV), with respect to replication in the skin and exit from the host. Recombinant MDVs were generated that express either the enhanced GFP (eGFP) or monomeric RFP (mRFP) fused to the UL47 (VP13/14) herpesvirus tegument protein. These viruses exhibited no alteration in pathogenic potential and expressed abundant UL47-eGFP or -mRFP in feather follicle epithelial cells in vivo. Using laser scanning confocal microscopy, it was evident that these two similar, but distinguishable, viruses were able to replicate within the same cells of their natural host. Evidence of superinfection inhibition was also observed. These results have important implications for two reasons. First, these results show that during natural infection, both dual infection of cells and superinfection inhibition can co-occur at the cellular level. Secondly, vaccination against MDV with homologous alphaherpesvirus like attenuated GaHV-2, or non-oncogenic GaHV-3 or meleagrid herpesvirus (MeHV-1) has driven the virus to greater virulence and these results implicate the potential for genetic exchange between homologous avian alphaherpesviruses that could drive increased virulence. Because the live attenuated varicella vaccine is currently being administered to children, who in turn could be superinfected by wild-type VZV, this could potentiate recombination events of VZV as well. PMID:22629393

Jarosinski, Keith W.

2012-01-01

275

Isotopes of Pennies  

NSDL National Science Digital Library

This lab activity from Science Netlinks is designed to explain the weighted averages that are used in average atomic mass calculations. Students can be expected to learn that isotopes of an element have different masses; that isotopes are atoms of the same element that have different numbers of neutrons; and that atomic mass is the weighted average of the naturally occurring isotopes of an element.

Netlinks, Science; Science, American A.

276

The atomic weight and isotopic composition of boron and their variation in nature  

SciTech Connect

The boron isotopic composition and atomic weight value and their variation in nature are reviewed. Questions are raised about the previously recommended value and the uncertainty for the atomic weight. The problem of what constitutes an acceptable range for normal material and what should then be considered geologically exceptional is discussed. Recent measurements make some previous decisions in need of re-evaluation.

Holden, N.E.

1993-08-01

277

EasyDelta: a spreadsheet for kinetic modeling of the stable carbon isotope composition of natural gases  

Microsoft Academic Search

A new kinetic model and an Excel spreadsheet program for modeling the stable carbon isotope composition of natural gases is provided in this paper. The model and spreadsheet could be used to describe and predict changes in stable carbon isotopes of natural gases under both experimental and geological conditions with heating temperature or geological time. The user-friendly spreadsheet, based on

Yan-Rong Zou; Lianyuan Wang; Yanhua Shuai; Pingan Peng

278

EasyDelta: A spreadsheet for kinetic modeling of the stable carbon isotope composition of natural gases  

Microsoft Academic Search

A new kinetic model and an Excel spreadsheet program for modeling the stable carbon isotope composition of natural gases is provided in this paper. The model and spreadsheet could be used to describe and predict the variances in stable carbon isotope of natural gases under both experimental and geological conditions with heating temperature or geological time. It is a user-friendly

Yan-Rong Zou; Lianyuan Wang; Yanhua Shuai; Pingan Peng

2005-01-01

279

Characterization of naturally occurring cutaneous neurofibromatosis in Holstein cattle. A disorder resembling neurofibromatosis type 1 in humans.  

PubMed

Neurofibromatosis in cattle is typically a noncutaneous disease. A small group of cows in a Holstein dairy herd developed cutaneous neurofibromatosis. This unique condition was investigated and compared with neurofibromatosis type 1 (NF1) in humans. All cutaneous lesions but one were consistent with neurofibromas in noncutaneous sites in cattle and neurofibromas in patients with NF1. One bovine lesion was classified as a neurofibrosarcoma. Immunohistochemistry and electron microscopy supported Schwannian differentiation in benign and malignant lesions. Linkage analysis with a polymorphism in the bovine NF1 gene confirmed that two affected animals from the same sire inherited the same paternal NF1 allele. Bovine cutaneous neurofibromatosis is a naturally occurring disease in this group of animals, characterized by skin tumors morphologically identical to those of NF1. An informative polymorphism at the NF1 locus of two animals and their sire suggests this disorder may be caused by hereditary mutations at the bovine NF1 locus. PMID:7977647

Sartin, E A; Doran, S E; Riddell, M G; Herrera, G A; Tennyson, G S; D'Andrea, G; Whitley, R D; Collins, F S

1994-11-01

280

A method for the determination of vanadium and iron oxidation states in naturally occurring oxides and silicates  

USGS Publications Warehouse

A valence-specific analytical method for determining V3+ in ore minerals has been developed that involves two steps: dissolution of a mineral sample without disturbing the V3+/Vtot ratio, followed by determination of V3+ in the presence of V4+. The samples are dissolved in a mixture of hydrofluoric and sulphuric acids at 100?? in Teflon-lined reaction vessels. Tervalent vanadium is then determined colorimetrically by formation of a V3+-thiocyanate complex in aqueous-acetone medium. Fe3+ is measured semi-quantitatively in the same solution. The method has been tested with two naturally occurring samples containing vanadium and iron. The results obtained were supported by those obtained by other methods, including electron spin resonance spectroscopy, thermogravimetric analysis, and Mo??ssbauer spectroscopy. ?? 1985.

Wanty, R.B.; Goldhaber, M.B.

1985-01-01

281

Capsid protein identification and analysis of mature Triatoma virus (TrV) virions and naturally occurring empty particles.  

PubMed

Triatoma virus (TrV) is a non-enveloped +ssRNA virus belonging to the insect virus family Dicistroviridae. Mass spectrometry (MS) and gel electrophoresis were used to detect the previously elusive capsid protein VP4. Its cleavage sites were established by sequencing the N-terminus of the protein precursor and MS, and its stoichiometry with respect to the other major capsid proteins (VP1-3) was found to be 1:1. We also characterized the polypeptides comprising the naturally occurring non-infectious empty capsids, i.e., RNA-free TrV particles. The empty particles were composed of VP0-VP3 plus at least seven additional polypeptides, which were identified as products of the capsid precursor polyprotein. We conclude that VP4 protein appears as a product of RNA encapsidation, and that defective processing of capsid proteins precludes genome encapsidation. PMID:21030058

Agirre, Jon; Aloria, Kerman; Arizmendi, Jesus M; Iloro, Ibn; Elortza, Flix; Snchez-Eugenia, Rubn; Marti, Gerardo A; Neumann, Emmanuelle; Rey, Flix A; Gurin, Diego M A

2011-01-01

282

Geochemical and Strontium Isotope Characterization of Produced Waters from Marcellus Shale Natural Gas Extraction  

SciTech Connect

Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of 375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (?{sub Sr}{sup SW} = +13.8 to +41.6, where ?{sub Sr}{sup SW} is the deviation of the {sup 87}Sr/{sup 86}Sr ratio from that of seawater in parts per 10{sup 4}); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate between Marcellus Formation produced water and other potential sources of TDS into ground or surface waters.

Chapman, Elizabeth C; Capo, Rosemary C.; Stewart, Brian W.; Kirby, Carl S.; Hammack, Richard W.; Schroeder, Karl T.; Edenborn, Harry M.

2012-03-20

283

Geochemical and Strontium Isotope Characterization of Produced Waters from Marcellus Shale Natural Gas Extraction  

SciTech Connect

Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of ?375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (?Sr SW = +13.8 to +41.6, where ?Sr SW is the deviation of the 87Sr/86Sr ratio from that of seawater in parts per 104); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate between Marcellus Formation produced water and other potential sources of TDS into ground or surface waters.

Elizabeth C. Chapman, Rosemary C. Capo, Brian W. Stewart,*, Carl S. Kirby, Richard W. Hammack,

2012-02-24

284

Isotopic disequilibrium effects in leaching of natural uraninite and thorianite  

SciTech Connect

Fractional leach rates of /sup 228/Th that are greater than those of /sup 232/Th from natural uraninite and thorianite have been interpreted by Eyal and Fleischer in terms of ..cap alpha..-decay damage to the crystal lattice. An alternative interpretation proposed here is that the enhanced leaching of /sup 228/Th is due to its presence as interstitial ions.

Vance, E.R.; Gascoyne, M.

1987-09-01

285

Naturally Occurring Variation in the Glutathione-S-Transferase 4 Gene Determines Neurodegeneration After Traumatic Brain Injury  

PubMed Central

Abstract Aim: Genetic factors are important for outcome after traumatic brain injury (TBI), although exact knowledge of relevant genes/pathways is still lacking. We here used an unbiased approach to define differentially activated pathways between the inbred DA and PVG rat strains. The results prompted us to study further if a naturally occurring genetic variation in glutathione-S-transferase alpha 4 (Gsta4) affects the outcome after TBI. Results: Survival of neurons after experimental TBI is increased in PVG compared to the DA strain. Global expression profiling analysis shows the glutathione metabolism pathway to be the most regulated between the strains, with increased Gsta4 in PVG among top regulated transcripts. A congenic strain (R5) with a PVG genomic insert containing the Gsta4 gene on DA background displays a reversal of the strain pattern for Gsta4 expression and increased survival of neurons compared to DA. Gsta4 is known to effectively reduce 4-hydroxynonenal (4-HNE), a noxious by-product of lipid peroxidation. Immunostaining of 4-HNE was evident in both rat and human TBI. Intracerebral injection of 4-HNE resulted in neurodegeneration with increased levels of a marker for nerve injury in cerebrospinal fluid of DA compared to R5. Innovation: These findings provide strong support for the notion that the inherent capability of coping with increased 4-HNE after TBI affects outcome in terms of nerve cell loss. Conclusion: A naturally occurring variation in Gsta4 expression in rats affects neurodegeneration after TBI. Further studies are needed to explore if genetic variability in Gsta4 can be associated to outcome also in human TBI. Antioxid. Redox Signal. 18, 784794. PMID:22881716

Strom, Mikael; Lindblom, Rickard; Aeinehband, Shahin; Bellander, Bo-Michael; Nyengaard, Jens R.; Lidman, Olle; Piehl, Fredrik

2013-01-01

286

The Effect of Naturally Occurring Chronic Kidney Disease on the Micro-Structural and Mechanical Properties of Bone  

PubMed Central

Chronic kidney disease (CKD) is a growing public health concern worldwide, and is associated with marked increase of bone fragility. Previous studies assessing the effect of CKD on bone quality were based on biopsies from human patients or on laboratory animal models. Such studies provide information of limited relevance due to the small size of the samples (biopsies) or the non-physiologic CKD syndrome studied (rodent models with artificially induced CKD). Furthermore, the type, architecture, structure and biology of the bone of rodents are remarkably different from human bones; therefore similar clinicopathologic circumstances may affect their bones differently. We describe the effects of naturally occurring CKD with features resembling human CKD on the skeleton of cats, whose bone biology, structure and composition are remarkably similar to those of humans. We show that CKD causes significant increase of resorption cavity density compared with healthy controls, as well as significantly lower cortical mineral density, cortical cross-sectional area and cortical cross-sectional thickness. Young's modulus, yield stress, and ultimate stress of the cortical bone material were all significantly decreased in the skeleton of CKD cats. Cancellous bone was also affected, having significantly lower trabecular thickness and bone volume over total volume in CKD cats compared with controls. This study shows that naturally occurring CKD has deleterious effects on bone quality and strength. Since many similarities exist between human and feline CKD patients, including the clinicopathologic features of the syndrome and bone microarchitecture and biology, these results contribute to better understanding of bone abnormalities associated with CKD. PMID:25333360

Meltzer, Hagar; Milrad, Moran; Brenner, Ori; Atkins, Ayelet; Shahar, Ron

2014-01-01

287

The effect of naturally occurring chronic kidney disease on the micro-structural and mechanical properties of bone.  

PubMed

Chronic kidney disease (CKD) is a growing public health concern worldwide, and is associated with marked increase of bone fragility. Previous studies assessing the effect of CKD on bone quality were based on biopsies from human patients or on laboratory animal models. Such studies provide information of limited relevance due to the small size of the samples (biopsies) or the non-physiologic CKD syndrome studied (rodent models with artificially induced CKD). Furthermore, the type, architecture, structure and biology of the bone of rodents are remarkably different from human bones; therefore similar clinicopathologic circumstances may affect their bones differently. We describe the effects of naturally occurring CKD with features resembling human CKD on the skeleton of cats, whose bone biology, structure and composition are remarkably similar to those of humans. We show that CKD causes significant increase of resorption cavity density compared with healthy controls, as well as significantly lower cortical mineral density, cortical cross-sectional area and cortical cross-sectional thickness. Young's modulus, yield stress, and ultimate stress of the cortical bone material were all significantly decreased in the skeleton of CKD cats. Cancellous bone was also affected, having significantly lower trabecular thickness and bone volume over total volume in CKD cats compared with controls. This study shows that naturally occurring CKD has deleterious effects on bone quality and strength. Since many similarities exist between human and feline CKD patients, including the clinicopathologic features of the syndrome and bone microarchitecture and biology, these results contribute to better understanding of bone abnormalities associated with CKD. PMID:25333360

Shipov, Anna; Segev, Gilad; Meltzer, Hagar; Milrad, Moran; Brenner, Ori; Atkins, Ayelet; Shahar, Ron

2014-01-01

288

Naturally occurring hypothermia is more advantageous than fever in severe forms of lipopolysaccharide- and Escherichia coli-induced systemic inflammation  

PubMed Central

The natural switch from fever to hypothermia observed in the most severe cases of systemic inflammation is a phenomenon that continues to puzzle clinicians and scientists. The present study was the first to evaluate in direct experiments how the development of hypothermia vs. fever during severe forms of systemic inflammation impacts the pathophysiology of this malady and mortality rates in rats. Following administration of bacterial lipopolysaccharide (LPS; 5 or 18 mg/kg) or of a clinical Escherichia coli isolate (5 109 or 1 1010 CFU/kg), hypothermia developed in rats exposed to a mildly cool environment, but not in rats exposed to a warm environment; only fever was revealed in the warm environment. Development of hypothermia instead of fever suppressed endotoxemia in E. coli-infected rats, but not in LPS-injected rats. The infiltration of the lungs by neutrophils was similarly suppressed in E. coli-infected rats of the hypothermic group. These potentially beneficial effects came with costs, as hypothermia increased bacterial burden in the liver. Furthermore, the hypotensive responses to LPS or E. coli were exaggerated in rats of the hypothermic group. This exaggeration, however, occurred independently of changes in inflammatory cytokines and prostaglandins. Despite possible costs, development of hypothermia lessened abdominal organ dysfunction and reduced overall mortality rates in both the E. coli and LPS models. By demonstrating that naturally occurring hypothermia is more advantageous than fever in severe forms of aseptic (LPS-induced) or septic (E. coli-induced) systemic inflammation, this study provides new grounds for the management of this deadly condition. PMID:22513748

Liu, Elaine; Lewis, Kevin; Al-Saffar, Hiba; Krall, Catherine M.; Singh, Anju; Kulchitsky, Vladimir A.; Corrigan, Joshua J.; Simons, Christopher T.; Petersen, Scott R.; Musteata, Florin M.; Bakshi, Chandra S.; Romanovsky, Andrej A.; Sellati, Timothy J.

2012-01-01

289

Elevated Appraisals of the Negative Impact of Naturally Occurring Life Events: A Risk Factor for Depressive and Anxiety Disorders  

PubMed Central

The tendency to appraise naturally occurring life events (LEs) as having high negative impact may be a predisposing factor for the development of depression and anxiety disorders. In the current study, appraisals of the negative impact of recent LEs were examined in relationship to depressive and anxiety disorders in a sample of 653 adolescents who were administered diagnostic and life stress interviews at ages 15 and 20. Participants appraisals of the negative impact of LEs reported at age 15 were statistically adjusted using investigator-based ratings to control for objective differences across LEs. Higher appraisals of the negative impact of LEs were associated with both past and current depressive and anxiety disorders at age 15 and predicted subsequent first onsets of depressive and anxiety disorders occurring between ages 15 and 20. In addition, appraisals of the negative impact of LEs were particularly elevated among those experiencing both a depressive and anxiety disorder over the course of the study. The findings suggest that systematically elevated appraisals of the negative impact of LEs is a predisposing factor for depression and anxiety disorders and may represent a specific risk factor for co-morbid depression and anxiety in mid-adolescence and early adulthood. Keywords: depression; anxiety; stress appraisals; prospective study; PMID:21845380

Espejo, Emmanuel P.; Hammen, Constance; Brennan, Patricia A.

2012-01-01

290

Naturally-occurring tetrahydro-?-carboline alkaloids derived from tryptophan are oxidized to bioactive ?-carboline alkaloids by heme peroxidases.  

PubMed

?-Carbolines are indole alkaloids that occur in plants, foods, and endogenously in mammals and humans, and which exhibit potent biological, psychopharmacological and toxicological activities. They form from naturally-occurring tetrahydro-?-carboline alkaloids arising from tryptophan by still unknown way and mechanism. Results in this research show that heme peroxidases catalyzed the oxidation of tetrahydro-?-carbolines (i.e. 1,2,3,4-tetrahydro-?-carboline-3-carboxylic acid and 1-methyl-1,2,3,4-tetrahydro-?-carboline-3-carboxylic acid) into aromatic ?-carbolines (i.e. norharman and harman, respectively). This oxidation followed a typical catalytic cycle of peroxidases through redox intermediates I, II, and ferric enzyme. Both, plant peroxidases (horseradish peroxidase, HRP) and mammalian peroxidases (myeloperoxidase, MPO and lactoperoxidase, LPO) catalyzed the oxidation in an efficient manner as determined by kinetic parameters (VMAX and KM). Oxidation of tetrahydro-?-carbolines was inhibited by peroxidase inhibitors such as sodium azide, ascorbic acid, hydroxylamine and excess of H2O2. The formation of aromatic ?-carbolines by heme peroxidases can help to explain the presence and activity of these compounds in biological systems. PMID:25035927

Herraiz, Toms; Galisteo, Juan

2014-08-15

291

Inhibition of ubiquitin-proteasome pathway-mediated I?B? degradation by a naturally occurring antibacterial peptide  

PubMed Central

Induction of NF-?Bdependent gene expression plays an important role in a number of biological processes including inflammation and ischemia-reperfusion injury. However, few attempts aimed at selective regulation of this transcription factor have been successful. We report here that a naturally occurring antibacterial peptide PR39 reversibly binds to the ?7 subunit of the 26S proteasome and blocks degradation of NF-?B inhibitor I?B? by the ubiquitin-proteasome pathway without affecting overall proteasome activity. I?B? phosphorylation and ubiquitination occur normally after PR39 treatment, and binding of valosin-containing proteins is not impaired. The inhibition of I?B? degradation abolishes induction of NF-?Bdependent gene expression in cell culture and in mouse models of acute pancreatitis and myocardial infarction, including upregulation of endothelial adhesion proteins VCAM-1 and ICAM-1. In the latter model, sustained infusion of PR39 peptide resulted in significant reduction of myocardial infarct size. PR39 and related peptides may provide novel means to regulate cellular function and to control of NF-?Bdependent gene expression for therapeutic purposes. PMID:10930447

Gao, Youhe; Lecker, Stewart; Post, Mark J.; Hietaranta, Antti J.; Li, Jian; Volk, Rudiger; Li, Min; Sato, Kaori; Saluja, Ashok K.; Steer, Michael L.; Goldberg, Alfred L.; Simons, Michael

2000-01-01

292

Effects of Naturally Occurring Six- and Twelve-Nucleotide Inserts on Newcastle Disease Virus Replication and Pathogenesis  

PubMed Central

Newcastle disease virus (NDV) isolates contain genomes of 15,186, 15,192 or 15,198 nucleotides (nt). The length differences reflect a 6-nt insert in the 5? (downstream) non-translated region (NTR) of the N gene (15,192-nt genome) or a 12-nt insert in the ORF encoding the P and V proteins (causing a 4-amino acid insert; 15,198-nt genome). We evaluated the role of these inserts in the N and P genes on viral replication and pathogenicity by inserting them into genomes of two NDV strains that have natural genome lengths of 15,186 nt and represent two different pathotypes, namely the mesogenic strain Beaudette C (BC) and the velogenic strain GB Texas (GBT). Our results showed that the 6-nt and 12-nt inserts did not detectably affect N gene expression or P protein function. The inserts had no effect on the replication or virulence of the highly virulent GBT strain but showed modest degree of attenuation in mesogenic strain BC. We also deleted a naturally-occurring 6-nt insertion in the N gene from a highly virulent 15,192-nt genome-length virus, strain Banjarmasin. This resulted in reduced replication in vitro and reduced virulence in vivo. Thus, although these inserts had no evident effect on gene expression, protein function, or replication in vivo, they did affect virulence in two of the three tested strains. PMID:25093330

Paldurai, Anandan; Xiao, Sa; Kim, Shin-Hee; Kumar, Sachin; Nayak, Baibaswata; Samal, Sweety; Collins, Peter L.; Samal, Siba K.

2014-01-01

293

Radial growth rate increases in naturally occurring ponderosa pine trees: a late-20th century CO2 fertilization effect?  

PubMed

The primary objective of this study was to determine if gradually increasing levels of atmospheric CO2, as opposed to 'step' increases commonly employed in controlled studies, have a positive impact on radial growth rates of ponderosa pine (Pinus ponderosa) in natural environments, and to determine the spatial extent and variability of this growth enhancement. We developed a series of tree-ring chronologies from minimally disturbed sites across a spectrum of environmental conditions. A series of difference of means tests were used to compare radial growth post-1950, when the impacts of rising atmospheric CO2 are best expressed, with that pre-1950. Spearman's correlation was used to relate site stress to growth-rate changes. Significant increases in radial growth rates occurred post-1950, especially during drought years, with the greatest increases generally found at the most water-limited sites. Site harshness is positively related to enhanced radial growth rates. Atmospheric CO2 fertilization is probably operative, having a positive effect on radial growth rates of ponderosa pine through increasing water-use efficiency. A CO2-driven growth enhancement may affect ponderosa pine growing under both natural and controlled conditions. PMID:16866944

Soul, Peter T; Knapp, Paul A

2006-01-01

294

Thermoluminescence (TL) Analysis and Fading Studies of Naturally Occurring Salt Irradiated by 500 mGy Gamma Rays  

SciTech Connect

The aim of the present study was to investigate the potential of the naturally occurring salt for the dosimetry purposes, using TL. The fine powder samples (20 mg) were irradiated by {gamma}- rays from 500 mGy to 2500 mGy by using Theratron-780C Cobalt-60 source, however, this paper discusses about 500 mGy only. The TL glow curve peak parameters were studied by using Chen's peak shape equation. TL glow curves were compared with fitted curves using glow curve deconvolution (GCD) method by using Kitis expression. The kinetic parameter values (E, b and s) so calculated, are in good agreement with those available in literature. The calculated energy values were also verified by using various heating rate (VHR) method. {chi}{sup 2} test and figure of merit (FOM) calculation was done to accept the goodness of fit between the curves. Fading studies of the sample showed a good fitting between the curves. The analysis suggests that natural salt should be considered for dosimetry purposes.

Tiwari, Ramesh Chandra; Pau, Kham Suan [Department of Physics, Mizoram University: Tanhril Campus, Aizawl-796004, Mizoram (India)

2011-10-20

295

Ecological Physiology of Synechococcus sp. Strain SH-94-5, a Naturally Occurring Cyanobacterium Deficient in Nitrate Assimilation  

PubMed Central

Synechococcus sp. strain SH-94-5 is a nitrate assimilation-deficient cyanobacterium which was isolated from an ammonium-replete hot spring in central Oregon. While this clone could grow on ammonium and some forms of organic nitrogen as sole nitrogen sources, it could not grow on either nitrate or nitrite, even under conditions favoring passive diffusion. It was determined that this clone does not express functional nitrate reductase or nitrite reductase and that the lack of activity of either enzyme is not due to inactivation of the cyanobacterial nitrogen control protein NtcA. A few other naturally occurring cyanobacterial strains are also nitrate assimilation deficient, and phylogenetic analyses indicated that the ability to utilize nitrate has been independently lost at least four times during the evolutionary history of the cyanobacteria. This phenotype is associated with the presence of environmental ammonium, a negative regulator of nitrate assimilation gene expression, which may indicate that natural selection to maintain functional copies of nitrate assimilation genes has been relaxed in these habitats. These results suggest how the evolutionary fates of conditionally expressed genes might differ between environments and thereby effect ecological divergence and biogeographical structure in the microbial world. PMID:11425713

Miller, Scott R.; Castenholz, Richard W.

2001-01-01

296

Distribution of naturally occurring radioactivity and ?Cs in the marine sediment of Farasan Island, southern Red Sea, Saudi Arabia.  

PubMed

The present work is a part of a project dedicated to measure the marine radioactivity near the Saudi Arabian coasts of the Red Sea and Arabian Gulf for establishing a marine radioactivity database, which includes necessary information on the background levels of both naturally occurring and man-made radionuclides in the marine environment. Farasan Islands is a group of 84 islands (archipelago), under the administration of the Kingdom of Saudi Arabia, in the Red Sea with its main island of Farasan, which is 50 km off the coast of Jazan City. The levels of natural radioactivity of (238)U, (235)U, (226)Ra, (232)Th and (40)K and man-made radionuclides such as (137)Cs in the grab sediment and water samples around Farasan Island have been measured using gamma-ray spectroscopy. The average activity concentrations of (238)U, (235)U, (226)Ra, (232)Th, (40)K and (137)Cs in the sediment samples were found to be 35.46, 1.75, 3.31, 0.92, 34.34 and 0.14 Bq kg(-1), respectively. PMID:22923246

Al-Zahrany, A A; Farouk, M A; Al-Yousef, A A

2012-11-01

297

The contribution of naturally occurring polymorphisms in altering the biochemical and structural characteristics of HIV-1 subtype C protease.  

PubMed

Fourteen subtype B and C protease variants have been engineered in an effort to study whether the preexistent baseline polymorphisms, by themselves or in combination with drug resistance mutations, differentially alter the biochemical and structural features of the subtype C protease when compared with those of subtype B protease. The kinetic studies performed in this work showed that the preexistent polymorphisms in subtype C protease, by themselves, do not provide for a greater level of resistance. Inhibition analysis with eight clinically used protease inhibitors revealed that the natural polymorphisms found in subtype C protease, in combination with drug resistance mutations, can influence enzymatic catalytic efficiency and inhibitor resistance. Structural analyses of the subtype C protease bound to nelfinavir and indinavir showed that these inhibitors form similar interactions with the residues in the active site of subtype B and C proteases. It also revealed that the naturally occurring polymorphisms could alter the position of the outer loops of the subtype C protease, especially the 60's loop. PMID:18092815

Coman, Roxana M; Robbins, Arthur H; Fernandez, Marty A; Gilliland, C Taylor; Sochet, Anthony A; Goodenow, Maureen M; McKenna, Robert; Dunn, Ben M

2008-01-15

298

Diagnosis of a naturally occurring dual infection of layer chickens with fowlpox virus and gallid herpesvirus 1 (infectious laryngotracheitis virus).  

PubMed

An outbreak of acute respiratory disease in layers was diagnosed as being of dual nature due to fowlpox and infectious laryngotracheitis using a multidisciplinary approach including virus isolation, histopathology, electron microscopy and polymerase chain reaction (PCR). The diagnosis was based on virus isolation of gallid herpesvirus 1 (GaHV-1) in chicken kidney cells and fowlpox virus (FWPV) in 9-day-old chicken embryonated eggs inoculated via the chorioallantoic membrane. The histopathology of tracheas from dead birds revealed intra-cytoplasmic and intra-nuclear inclusions suggestive of poxvirus and herpesvirus involvement. The presence of FWPV was further confirmed by electron microscopy, PCR and histology. All FWPV isolates contained the long terminal repeats of reticuloendotheliosis virus as demonstrated by PCR. GaHV-1 isolates were detected by PCR and were shown to have a different restriction fragment length polymorphism pattern when compared with the chicken embryo origin SA2 vaccine strain; however, they shared the same pattern with the Intervet chicken embryo origin vaccine strain. This is a first report of dual infection of chickens with GaHV-1 and naturally occurring FWPV with reticuloendotheliosis virus insertions. Further characterization of the viruses was carried out and the results are reported here. PMID:20390533

Diallo, Ibrahim S; Taylor, Jim; Gibson, John; Hoad, John; De Jong, Amanda; Hewitson, Glen; Corney, Bruce G; Rodwell, Barry J

2010-02-01

299

Ecological physiology of Synechococcus sp. strain SH-94-5, a naturally occurring cyanobacterium deficient in nitrate assimilation  

NASA Technical Reports Server (NTRS)

Synechococcus sp. strain SH-94-5 is a nitrate assimilation-deficient cyanobacterium which was isolated from an ammonium-replete hot spring in central Oregon. While this clone could grow on ammonium and some forms of organic nitrogen as sole nitrogen sources, it could not grow on either nitrate or nitrite, even under conditions favoring passive diffusion. It was determined that this clone does not express functional nitrate reductase or nitrite reductase and that the lack of activity of either enzyme is not due to inactivation of the cyanobacterial nitrogen control protein NtcA. A few other naturally occurring cyanobacterial strains are also nitrate assimilation deficient, and phylogenetic analyses indicated that the ability to utilize nitrate has been independently lost at least four times during the evolutionary history of the cyanobacteria. This phenotype is associated with the presence of environmental ammonium, a negative regulator of nitrate assimilation gene expression, which may indicate that natural selection to maintain functional copies of nitrate assimilation genes has been relaxed in these habitats. These results suggest how the evolutionary fates of conditionally expressed genes might differ between environments and thereby effect ecological divergence and biogeographical structure in the microbial world.

Miller, S. R.; Castenholz, R. W.

2001-01-01

300

Regulation of rat magnocellular neurosecretory system by D-aspartate: evidence for biological role(s) of a naturally occurring free D-amino acid in mammals  

Microsoft Academic Search

Little evidence is available for the physiological function of ?-amino acids in species other than bacteria. Here we demonstrate that naturally occurring free ?-aspartate (?-Asp) is present in all magnocellular neurons of rat hypothalamus. The levels of this naturally occurring ?-amino acid were elevated during lactation and returned to normal thereafter in the magnocellular neurosecretory system, which produces oxytocin, a

H Wang; H Wolosker; J Pevsner; S H Snyder; D J Selkoe

2000-01-01

301

Survey of naturally occurring hazardous materials in deep geologic formations: a perspective on the relative hazard of deep burial of nuclear wastes  

Microsoft Academic Search

Hazards associated with deep burial of solidified nuclear waste are considered with reference to toxic elements in naturally occurring ore deposits. This problem is put into perspective by relating the hazard of a radioactive waste repository to that of naturally occurring geologic formations. The basis for comparison derives from a consideration of safe drinking water levels. Calculations for relative toxicity

K. A. Tonnessen; J. J. Cohen

1977-01-01

302

Natural mass-dependent variations in the isotopic composition of molybdenum  

Microsoft Academic Search

We present the first observations of natural mass-dependent fractionation of the isotopic composition of molybdenum (Mo), using multi-collector inductively coupled plasma mass spectrometry. Variations in the isotopic composition of Mo are reported as ?97\\/95Mo (=((97Mo\\/95Mo)sample\\/(97Mo\\/95Mo)standard?1)1000). External analytical precision of ?97\\/95Mo is 1 between sediments deposited under anoxic conditions (?97\\/95Mo=+1.02 to +1.52 relative to our in-house standard) and ferromanganese nodules (?97\\/95Mo=?0.63

J Barling; G. L Arnold; A. D Anbar

2001-01-01

303

Analysis of reserve pit sludge from unconventional natural gas hydraulic fracturing and drilling operations for the presence of technologically enhanced naturally occurring radioactive material (TENORM).  

PubMed

Soil and water (sludge) obtained from reserve pits used in unconventional natural gas mining was analyzed for the presence of technologically enhanced naturally occurring radioactive material (TENORM). Samples were analyzed for total gamma, alpha, and beta radiation, and specific radionuclides: beryllium, potassium, scandium, cobalt, cesium, thallium, lead-210 and -214, bismuth-212 and -214, radium-226 and -228, thorium, uranium, and strontium-89 and -90. Laboratory analysis confirmed elevated beta readings recorded at 1329 311 pCi/g. Specific radionuclides present in an active reserve pit and the soil of a leveled, vacated reserve pit included 232Thorium decay series (228Ra, 228Th, 208Tl), and 226Radium decay series (214Pb, 214Bi, 210Pb) radionuclides. The potential for impact of TENORM to the environment, occupational workers, and the general public is presented with potential health effects of individual radionuclides. Current oversight, exemption of TENORM in federal and state regulations, and complexity in reporting are discussed. PMID:23552651

Rich, Alisa L; Crosby, Ernest C

2013-01-01

304

Novel and nontraditional use of stable isotope tracers to study metal bioavailability from natural particles.  

PubMed

We devised a novel tracing approach that involves enriching test organisms with a stable metal isotope of low natural abundance prior to characterizing metal bioavailability from natural inorganic particles. In addition to circumventing uncertainties associated with labeling natural particles and distinguishing background metals, the proposed "reverse labeling" technique overcomes many drawbacks inherent to using radioisotope tracers. Specifically, we chronically exposed freshwater snails ( Lymnaea stagnalis ) to synthetic water spiked with Cu that was 99.4% (65)Cu to increase the relative abundance of (65)Cu in the snail's tissues from ~32% to >80%. The isotopically enriched snails were then exposed to benthic algae mixed with Cu-bearing Fe-Al particles collected from the Animas River (Colorado), an acid mine drainage impacted river. We used (63)Cu to trace Cu uptake from the natural particles and inferred their bioavailability from calculation of Cu assimilation into tissues. Cu assimilation from these particles was 44%, indicating that 44% of the particulate Cu was absorbed by the invertebrate. This demonstrates that inorganic particulate Cu can be bioavailable. The reverse labeling approach shows great potential in various scientific areas such as environmental contamination and nutrition for addressing questions involving uptake of an element that naturally has multiple isotopes. PMID:23458345

Croteau, Marie-Nole; Cain, Daniel J; Fuller, Christopher C

2013-04-01

305

The inactivation of human CYP2E1 by phenethyl isothiocyanate, a naturally occurring chemopreventive agent, and its oxidative bioactivation.  

PubMed

Phenethylisothiocyanate (PEITC), a naturally occurring isothiocyanate and potent cancer chemopreventive agent, works by multiple mechanisms, including the inhibition of cytochrome P450 (P450) enzymes, such as CYP2E1, that are involved in the bioactivation of carcinogens. PEITC has been reported to be a mechanism-based inactivator of some P450s. We describe here the possible mechanism for the inactivation of human CYP2E1 by PEITC, as well as the putative intermediate that might be involved in the bioactivation of PEITC. PEITC inactivated recombinant CYP2E1 with a partition ratio of 12, and the inactivation was not inhibited in the presence of glutathione (GSH) and not fully recovered by dialysis. The inactivation of CYP2E1 by PEITC is due to both heme destruction and protein modification, with the latter being the major pathway for inactivation. GSH-adducts of phenethyl isocyanate (PIC) and phenethylamine were detected during the metabolism by CYP2E1, indicating formation of PIC as a reactive intermediate following P450-catalyzed desulfurization of PEITC. Surprisingly, PIC bound covalently to CYP2E1 to form protein adducts but did not inactivate the enzyme. Liquid chromatography mass spectroscopy analysis of the inactivated CYP2E1 apo-protein suggests that a reactive sulfur atom generated during desulfurization of PEITC is involved in the inactivation of CYP2E1. Our data suggest that the metabolism of PEITC by CYP2E1 that results in the inactivation of CYP2E1 may occur by a mechanism similar to that observed with other sulfur-containing compounds, such as parathion. Digestion of the inactivated enzyme and analysis by SEQUEST showed that Cys 268 may be the residue modified by PIC. PMID:23371965

Yoshigae, Yasushi; Sridar, Chitra; Kent, Ute M; Hollenberg, Paul F

2013-04-01

306

Influence of Asellus aquaticus on Escherichia coli, Klebsiella pneumoniae, Campylobacter jejuni and naturally occurring heterotrophic bacteria in drinking water.  

PubMed

Water lice, Asellus aquaticus (isopoda), frequently occur in drinking water distribution systems where they are a nuisance to consumers and water utilities. Whether they are solely an aesthetic problem or also affect the microbial water quality is a matter of interest. We studied the influence of A. aquaticus on microbial water quality in non-chlorinated drinking water in controlled laboratory experiments. Pure cultures of the indicator organisms Escherichia coli and Klebsiella pneumoniae and the pathogen Campylobacter jejuni as well as naturally occurring heterotrophic drinking water bacteria (measured as heterotrophic plate counts, HPC) were investigated in microcosms at 7 C, containing non-sterilised drinking water, drinking water sediment and A. aquaticus collected from a non-chlorinated ground water based drinking water supply system. Concentrations of E. coli, K. pneumoniae and C. jejuni decreased over time, following a first order decay with half lives of 5.3, 18.4 and 1.3 days, respectively. A. aquaticus did not affect survival of indicators and pathogens substantially whereas HPC were influenced by presence of dead A. aquaticus. Growth rates increased with an average of 48% for bacteria grown on R-2A agar and an average of 83% for bacteria grown on yeast extract agar when dead A. aquaticus were present compared to no and living A. aquaticus present. A. aquaticus associated E. coli, K. pneumoniae and C. jejuni were measured (up to 25 per living and 500 per dead A. aquaticus) and so were A. aquaticus associated heterotrophic bacteria (>1.8*10(4) CFU per living and >6*10(4) CFU per dead A. aquaticus). A. aquaticus did not serve as an optimised habitat that increased survival of indicators and pathogens, since A. aquaticus associated E. coli, K. pneumoniae and C. jejuni were only measured as long as the bacteria were also present in the water and sediment. PMID:22884244

Christensen, Sarah C B; Nissen, Erling; Arvin, Erik; Albrechtsen, Hans-Jrgen

2012-10-15

307

Naturally Occurring Peer Support through Social Media: The Experiences of Individuals with Severe Mental Illness Using YouTube.  

PubMed

Increasingly, people with diverse health conditions turn to social media to share their illness experiences or seek advice from others with similar health concerns. This unstructured medium may represent a platform on which individuals with severe mental illness naturally provide and receive peer support. Peer support includes a system of mutual giving and receiving where individuals with severe mental illness can offer hope, companionship, and encouragement to others facing similar challenges. In this study we explore the phenomenon of individuals with severe mental illness uploading videos to YouTube, and posting and responding to comments as a form of naturally occurring peer support. We also consider the potential risks and benefits of self-disclosure and interacting with others on YouTube. To address these questions, we used qualitative inquiry informed by emerging techniques in online ethnography. We analyzed n?=?3,044 comments posted to 19 videos uploaded by individuals who self-identified as having schizophrenia, schizoaffective disorder, or bipolar disorder. We found peer support across four themes: minimizing a sense of isolation and providing hope; finding support through peer exchange and reciprocity; sharing strategies for coping with day-to-day challenges of severe mental illness; and learning from shared experiences of medication use and seeking mental health care. These broad themes are consistent with accepted notions of peer support in severe mental illness as a voluntary process aimed at inclusion and mutual advancement through shared experience and developing a sense of community. Our data suggest that the lack of anonymity and associated risks of being identified as an individual with severe mental illness on YouTube seem to be overlooked by those who posted comments or uploaded videos. Whether or not this platform can provide benefits for a wider community of individuals with severe mental illness remains uncertain. PMID:25333470

Naslund, John A; Grande, Stuart W; Aschbrenner, Kelly A; Elwyn, Glyn

2014-01-01

308

Naturally occurring Influenza A virus subtype H1N2 infection in a Midwest United States mink (Mustela vison) ranch.  

PubMed

Influenza A virus (FLUAV) causes acute respiratory disease in humans and a variety of animal species. The virus tends to remain within the species of origin; nonetheless, naturally occurring cross-species transmission of FLUAV has been periodically documented. Multiple cross-species transmissions of FLUAV have been reported from companion animals and captive wild animals, neither of which is historically considered as natural hosts of FLUAV. In the fall of 2010, mink (Mustela vison) inhabiting a 15,000-head mink farm in the Midwest United States experienced persistent severe respiratory distress and nose and/or mouth bleeding. Mink losses averaged approximately 10 animals per day. Six dead mink at 6 months of age were submitted to the Iowa State University Veterinary Diagnostic Laboratory for diagnostic investigation. Gross and microscopic examinations revealed that all 6 mink had hemorrhagic bronchointerstitial pneumonia. Hemolytic Escherichia coli was isolated from lungs, probably accounting for hemorrhagic pneumonia. All animals tested negative for Canine distemper virus and Aleutian mink disease virus. Interestingly, FLUAV of H1N2 subtype, which contained the matrix gene of swine lineage, was detected in the lungs. Serological follow-up on mink that remained in the ranch until pelting also confirmed that the ranch had been exposed to FLUAV of H1 subtype (? clade). The case study suggests that FLUAV should be included in the differential diagnosis when mink experience epidemics of respiratory disease. Since the source of FLUAV appeared to be uncooked turkey meat, feeding animals fully cooked ration should be considered as a preventive measure. PMID:22362526

Yoon, Kyoung-Jin; Schwartz, Kent; Sun, Dong; Zhang, Jianqiang; Hildebrandt, Hugh

2012-03-01

309

Naturally Occurring Peer Support through Social Media: The Experiences of Individuals with Severe Mental Illness Using YouTube  

PubMed Central

Increasingly, people with diverse health conditions turn to social media to share their illness experiences or seek advice from others with similar health concerns. This unstructured medium may represent a platform on which individuals with severe mental illness naturally provide and receive peer support. Peer support includes a system of mutual giving and receiving where individuals with severe mental illness can offer hope, companionship, and encouragement to others facing similar challenges. In this study we explore the phenomenon of individuals with severe mental illness uploading videos to YouTube, and posting and responding to comments as a form of naturally occurring peer support. We also consider the potential risks and benefits of self-disclosure and interacting with others on YouTube. To address these questions, we used qualitative inquiry informed by emerging techniques in online ethnography. We analyzed n?=?3,044 comments posted to 19 videos uploaded by individuals who self-identified as having schizophrenia, schizoaffective disorder, or bipolar disorder. We found peer support across four themes: minimizing a sense of isolation and providing hope; finding support through peer exchange and reciprocity; sharing strategies for coping with day-to-day challenges of severe mental illness; and learning from shared experiences of medication use and seeking mental health care. These broad themes are consistent with accepted notions of peer support in severe mental illness as a voluntary process aimed at inclusion and mutual advancement through shared experience and developing a sense of community. Our data suggest that the lack of anonymity and associated risks of being identified as an individual with severe mental illness on YouTube seem to be overlooked by those who posted comments or uploaded videos. Whether or not this platform can provide benefits for a wider community of individuals with severe mental illness remains uncertain. PMID:25333470

Naslund, John A.; Grande, Stuart W.; Aschbrenner, Kelly A.; Elwyn, Glyn

2014-01-01

310

Modeling the effects of naturally occurring organic carbon on chlorinated ethene transport to a public supply well.  

PubMed

The vulnerability of public supply wells to chlorinated ethene (CE) contamination in part depends on the availability of naturally occurring organic carbon to consume dissolved oxygen (DO) and initiate reductive dechlorination. This was quantified by building a mass balance model of the Kirkwood-Cohansey aquifer, which is widely used for public water supply in New Jersey. This model was built by telescoping a calibrated regional three-dimensional (3D) MODFLOW model to the approximate capture zone of a single public supply well that has a history of CE contamination. This local model was then used to compute a mass balance between dissolved organic carbon (DOC), particulate organic carbon (POC), and adsorbed organic carbon (AOC) that act as electron donors and DO, CEs, ferric iron, and sulfate that act as electron acceptors (EAs) using the Sequential Electron Acceptor Model in three dimensions (SEAM3D) code. SEAM3D was constrained by varying concentrations of DO and DOC entering the aquifer via recharge, varying the bioavailable fraction of POC in aquifer sediments, and comparing observed and simulated vertical concentration profiles of DO and DOC. This procedure suggests that approximately 15% of the POC present in aquifer materials is readily bioavailable. Model simulations indicate that transport of perchloroethene (PCE) and its daughter products trichloroethene (TCE), cis-dichloroethene (cis-DCE), and vinyl chloride (VC) to the public supply well is highly sensitive to the assumed bioavailable fraction of POC, concentrations of DO entering the aquifer with recharge, and the position of simulated PCE source areas in the flow field. The results are less sensitive to assumed concentrations of DOC in aquifer recharge. The mass balance approach used in this study also indicates that hydrodynamic processes such as advective mixing, dispersion, and sorption account for a significant amount of the observed natural attenuation in this system. PMID:24372440

Chapelle, Francis H; Kauffman, Leon J; Widdowson, Mark A

2014-09-01

311

Multiple forms of metallothionein from the digestive gland of naturally occurring and cadmium-exposed mussels, Mytilus galloprovincialis  

NASA Astrophysics Data System (ADS)

Polymorphism of metallothioneins in the digestive gland of naturally occurring (control) and experimentally Cd-exposed mussels Mytilus galloprovincialis (200 g Cd l-1 14 days) was studied by applying the conventional methods of Sephadex column liquid chromatography (G-75 and DEAE A-25), and by an electrochemical method (DPASV) for determination of Cd, Zn and Cu concentrations in chromatographic fractions. In both control and Cd-exposed mussels, two distinct molecular mass components of the metallothioneins, monomeric (MT-10) and dimeric (MT-20), were resolved by Sephadex G-75 gel filtration chromatography. In control mussels, the MT-10 component was predominantly expressed as containing markedly higher constitutive levels of Zn (100) and Cu (10) than of Cd. Each of these two molecular mass components was further resolved into seven metal-rich peaks by anion-exchange chromatography. In Cd-exposed mussels the larger proportion of Cd was bound to the MT-20 than to the MT-10 component, suggesting that the dimeric component may be considered as a primarily inducible metallothionein. The elution positions of metal-binding maxima of Cd-exposed and control mussels on the respective DEAE chromatographic profiles were comparable. A great similarity in elution positions of Cd maxima between the composite and single-specimen samples was also observed. Our study confirms a high multiplicity of MT forms in mussels from the Mytilus genus not only under the laboratory high-level metal exposure conditions, but also at a natural seawater metal exposure level. The ecotoxicological significance of dimeric and monomeric MT forms, as well as their possible application in the biomonitoring of seawater for trace metals, has been considered.

Ivankovi?, Duica; Pavi?i?, Jasenka; Kozar, Sonja; Raspor, Biserka

2002-05-01

312

Punishment and reward sensitivity: are naturally occurring clusters in these traits related to eating and weight problems in adolescents?  

PubMed

Little is known about the role of sensitivity to punishment (SP) and reward (SR) in eating problems during adolescence. Therefore, the aim of the present study was to examine the naturally occurring clusters of high and low SP and SR among nonclinical adolescents and the between-cluster differences in various eating problems and weight. A total of 579 adolescents (14-19 years, 39.8% boys) completed the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ), the Behavioural Inhibition System and Behavioural Activation System scales (BIS/BAS scales), the Dutch Eating Behaviour Questionnaire and the Child Eating Disorder Examination Questionnaire and were weighed and measured. On the basis of the SPSRQ, four clusters were established, interpreted as lowSP lowSR, lowSP highSR, highSP highSR and highSP lowSR. These were associated with eating problems but not with adjusted body mass index. It seemed that specifically the highSP highSR cluster outscored the other clusters on eating problems. These results were partly replicated with the BIS/BAS scales, although less significant relations between the clusters and eating problems were found. The implications of the findings in terms of possible risk and protective clusters are discussed. PMID:23426856

Matton, Annelies; Goossens, Lien; Braet, Caroline; Vervaet, Myriam

2013-05-01

313

The influence of naturally occurring heterophilic anti-immunoglobulin antibodies on direct measurement of serum proteins using sandwich ELISAs.  

PubMed

Sandwich ELISAs have become a widely used method for the quantitative detection of serum proteins. However, they can be biased by a variety of interfering substances. As reported recently, we observed false-positive levels of interferon (IFN)-alpha and -beta in up to 27% of sera from healthy blood donors using commercial ELISAs. We now demonstrate that two different groups of naturally occurring heterophilic antibodies (IgG-type) are responsible for these titers. Group I (representing 85% of positive samples) binds to the Fab region of IgG from goat, mouse, rat, horse, and bovidae (but not rabbit). Group II (15%) recognizes an epitope in the Fc region of mouse, horse, bovine, and rabbit (but not goat or rat) immunoglobulins. The antibodies did not crossreact with human IgG subclasses but contributed to false-positive IgG rheumatoid factor levels obtained using a commercially available ELISA. To investigate the susceptibility of assays to these artifacts, various combinations of capture and detection antibodies have been tested. On this basis, we defined the relative risks that standard ELISAs might be influenced by heterophilic anti-immunoglobulin antibodies. In general, assays that use monoclonal antibodies for both capture and detection are less susceptible than others which include at least one polyclonal antiserum. However, only systems utilizing rabbit F(ab')(2) fragments have been found to be immune to this interference. PMID:10675759

Hennig, C; Rink, L; Fagin, U; Jabs, W J; Kirchner, H

2000-02-21

314

Trace element concentrations in transplanted and naturally occurring Unionidae mussels, water, sediments, and macrophytes in Cayuga Lake  

SciTech Connect

This report is a compilation of element concentration data for an EML program whose goal is to determine the environmental fate of combustion-produced pollutants released from a coal-fired electric generating station into an aquatic ecosystem. Because of the enormity of the data set, we have prepared this document to present the data base which will be used in our future interpretive scientific publications. The concentration data for 22 trace elements are reported for naturally occurring fresh water (Unionidae) mussels, macrophytes, lake water, and littoral sediments obtained from Cayuga Lake, NY, the site of the study. Also reported are concentration data for mussels collected from northern Lake George, NY which were transplanted into various locations in Cayuga Lake for periods of up to two years, recovered, and analyzed for the same trace elements. The description of the sampling sites, sampling methodologies, and the results of the analytical quality control programs are presented. Ratios of trace elements in different compartments of the Cayuga Lake ecosystem and correlation coefficients determined by comparing element concentrations in the biota, water, and sediment with distance from the coal-fired power plant are also presented. 21 refs., 2 figs., 33 tabs.

Silvestri, S.; Heit, M.; Klusek, C.S.

1988-08-01

315

Stage of action of naturally occurring andrographolides and their semisynthetic analogues against herpes simplex virus type 1 in vitro.  

PubMed

Andrographolide, an ENT-labdane diterpene, has been found to have activities against many viruses. Three free hydroxyls at C-3, C-14, and C-19 are involved in the activities. No stage of action has ever been explored. In this study, the naturally occurring compounds of andrographolide, 14-deoxy-11,12-didehydroandrographolide and 14-deoxyandrographolide, and eight semisynthetic analogues, modified at the three free OHs of andrographolide, were explored for their anti-HSV-1 activities. The concentrations that produced 80?% viable cells were used to test for both pre- and postinfections by using cytopathic effect reduction assays on Vero cell cultures. Three analogues, 14-acetyl-3,19-isopropylideneandrographolide, 14-acetylandrographolide, and 3,14,19-triacetylandrographolide, significantly exhibited preinfection step activity against the virus. For postinfection activity, only 3,19-isopropylideneandrographolide showed absolute inhibition of HSV-1 replication. Meanwhile, andrographolide exhibited slight inhibitory activities of 34.48??6.93?% and 56.90??2.65?% against HSV-1 for pre- and postinfection, respectively. The results confirm that the three hydroxyl moieties play a role in the anti-HSV-1 activity of andrographolide. From the study, it can be concluded that 14-acetyl analogues are good for blocking the viral entry, and 3,19-isopropylideneandrographolide, a cyclic dioxane analogue, is good for exerting postinfection anti-HSV-1 activity. PMID:21259187

Aromdee, Chantana; Suebsasana, Supawadee; Ekalaksananan, Tipaya; Pientong, Chamsai; Thongchai, Sasithorn

2011-06-01

316

Background dose-rates to reference animals and plants arising from exposure to naturally occurring radionuclides in aquatic environments.  

PubMed

In order to put dose-rates derived in environmental impact assessments into context, the International Commission on Radiological Protection (ICRP) has recommended the structuring of effects data according to background exposure levels. The ICRP has also recommended a suite of reference animals and plants (RAPs), including seven aquatic organisms, for use within their developing framework. In light of these propositions, the objective of this work was to collate information on activity concentrations of naturally occurring primordial radionuclides for marine and freshwater ecosystems and apply appropriate dosimetry models to derive absorbed dose-rates. Although coverage of activity concentration data is comprehensive for sediment and water, few, or in some cases no, data were found for some RAPs, e.g. for frogs (Ranidae) and freshwater grasses (Poaceae) for most radionuclides. The activity concentrations for individual radionuclides in both organisms and their habitat often exhibit standard deviations that are substantially greater than arithmetic mean values, reflecting large variability in activity concentrations. To take account of variability a probabilistic approach was adopted. The dominating radionuclides contributing to exposure in the RAPs are (40)K, (210)Po and (226)Ra. The mean unweighted and weighted dose-rates for aquatic RAPs are in the ranges 0.07-0.39 microGy h(-1) and 0.37-1.9 microGy h(-1) respectively. PMID:20530863

Hosseini, A; Beresford, N A; Brown, J E; Jones, D G; Phaneuf, M; Thrring, H; Yankovich, T

2010-06-01

317

Absence of geographic chromosomal variation in the roan and sable antelope and the cytogenetics of a naturally occurring hybrid.  

PubMed

The determination of geographic chromosomal variation in rare or endangered species, or those of special management concern, is important, since geographically defined cytotypes can negatively influence breeding programs involving founders drawn from widely divergent localities. We cytogenetically analyzed specimens of the roan (Hippotragus equinus) and sable antelope (H. niger) collected from widely divergent localities throughout their respective ranges. Each species was characterized by a diploid number of 60 and an invariant karyotype. In contrast to the absence of intraspecific variation, however, the two species differ with respect to centromeric constitutive heterochromatin and numbers of nucleolar organizer regions. These cytogenetic landmarks were subsequently used to verify an anecdotal account of a naturally occurring roan x sable hybrid. The data show that, despite their markedly distinct phenotypes, the roan and sable antelope are nonetheless sufficiently similar genetically to produce viable offspring. Hybridization, although a rare event between these species, is probably partly promoted by behavioral differences which are not always sufficient to prevent mating between them. PMID:8521725

Robinson, T J; Harley, E H

1995-01-01

318

Naturally occurring chronic gastritis and C pylori infection in the rhesus monkey: a potential model for gastritis in man.  

PubMed Central

Histological examination of the stomachs of Rhesus monkeys at autopsy showed chronic gastritis in a high proportion of all ages. Lesions consisted of mild to heavy infiltration of the lamina propria by lymphocytes, plasma cells, and histiocytes. The antrum was most consistently affected, but lesions were also present in the fundus and pylorus. Gastric Campylobacter-like organisms (GCLO) apparently identical to human C pylori were cultured and/or detected immunohistologically in several animals. Electron microscopy showed the spiral bacteria on the epithelial surface and in gastric pits. They did not penetrate the cells but were intimately attached to the apical plasma membrane and caused loss of microvilli. Antibodies to C pylori were detected in serum of the monkeys by ELISA. The immunospecificity of this antibody response was confirmed by Western blotting techniques. A small number of cynomolgus monkeys examined had gastritis, which may also be associated with the presence of C pylori. Baboons did not have gastritis, nor was C pylori cultured from their stomachs. The study indicates that the Rhesus monkey has a naturally occurring gastritis associated with C pylori infection and may therefore be a suitable experimental animal for the human disease. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 PMID:3371715

Baskerville, A; Newell, D G

1988-01-01

319

Molecular basis for the catalytic inactivity of a naturally occurring near-null variant of human ALOX15.  

PubMed

Mammalian lipoxygenases belong to a family of lipid-peroxidizing enzymes, which have been implicated in cardiovascular, hyperproliferative and neurodegenerative diseases. Here we report that a naturally occurring mutation in the hALOX15 gene leads to expression of a catalytically near-null enzyme variant (hGly422Glu). The inactivity may be related to severe misfolding of the enzyme protein, which was concluded from CD-spectra as well as from thermal and chemical stability assays. In silico mutagenesis experiments suggest that most mutations at hGly422 have the potential to induce sterical clash, which might be considered a reason for protein misfolding. hGly422 is conserved among ALOX5, ALOX12 and ALOX15 isoforms and corresponding hALOX12 and hALOX5 mutants also exhibited a reduced catalytic activity. Interestingly, in the hALOX5 Gly429Glu mutants the reaction specificity of arachidonic acid oxygenation was shifted from 5S- to 8S- and 12R-H(p)ETE formation. Taken together, our data indicate that the conserved glycine is of functional importance for these enzyme variants and most mutants at this position lose catalytic activity. PMID:23958500

Horn, Thomas; Ivanov, Igor; Di Venere, Almerinda; Kakularam, Kumar Reddy; Reddanna, Pallu; Conrad, Melanie L; Richter, Constanze; Scheerer, Patrick; Kuhn, Hartmut

2013-12-01

320

Semicarbazide-sensitive amine oxidase (SSAO) of the rat aorta. Interactions with some naturally occurring amines and their structural analogues.  

PubMed

The influence of a number of naturally occurring amines and their structural analogues has been examined on the metabolism of radiolabelled benzylamine (BZ) by the membrane bound semicarbazide-sensitive amine oxidase (SSAO) of the rat aorta. Only primary monoamines were effective in reducing the deamination of BZ. In the phenylethylamine series, addition of hydroxyl groups to the benzene ring decreased their potency as inhibitors while addition of a hydroxyl group at the beta position increased the inhibitory potency. Stereoselectivity of action was shown with octopamine, the L-isomer being the more active form. Kinetic analysis of these interactions showed predominantly competitive inhibition and kynuramine had the lowest Ki of 5.4 microM. The aliphatic monoamines, isoamylamine and isobutylamine both competed with BZ. 5-Hydroxytryptamine (5-HT) was the only amine that inhibited non-competitively. Direct evidence for metabolism by SSAO of some of the competing amines such as isoamylamine, phenylethylamine, tyramine and tryptamine was obtained by fluorimetric or radiochemical assays. The inhibitors clorgyline and (E)-2-(3',4'-dimethoxyphenyl)-3-fluoroallylamine (MDL 72145) were used to characterise the amine oxidase activity responsible for the deamination. Octopamine and phenylethanolamine (PeOH) were not SSAO substrates and inhibited BZ metabolism in the fluorimetric assay. It is possible that the activity of SSAO is controlled by octopamine released from sympathetic nerve endings or 5-HT released from platelets. PMID:2719723

Elliott, J; Callingham, B A; Sharman, D F

1989-05-01

321

A computer aided thermodynamic approach for predicting the formation of Z-DNA in naturally occurring sequences  

NASA Technical Reports Server (NTRS)

The ease with which a particular DNA segment adopts the left-handed Z-conformation depends largely on the sequence and on the degree of negative supercoiling to which it is subjected. We describe a computer program (Z-hunt) that is designed to search long sequences of naturally occurring DNA and retrieve those nucleotide combinations of up to 24 bp in length which show a strong propensity for Z-DNA formation. Incorporated into Z-hunt is a statistical mechanical model based on empirically determined energetic parameters for the B to Z transition accumulated to date. The Z-forming potential of a sequence is assessed by ranking its behavior as a function of negative superhelicity relative to the behavior of similar sized randomly generated nucleotide sequences assembled from over 80,000 combinations. The program makes it possible to compare directly the Z-forming potential of sequences with different base compositions and different sequence lengths. Using Z-hunt, we have analyzed the DNA sequences of the bacteriophage phi X174, plasmid pBR322, the animal virus SV40 and the replicative form of the eukaryotic adenovirus-2. The results are compared with those previously obtained by others from experiments designed to locate Z-DNA forming regions in these sequences using probes which show specificity for the left-handed DNA conformation.

Ho, P. S.; Ellison, M. J.; Quigley, G. J.; Rich, A.

1986-01-01

322

What do N isotopes tell us about the biogeochemistry of natural gradients? (Invited)  

NASA Astrophysics Data System (ADS)

The two stable isotopes of nitrogen (N) hold great promise for biogeochemistry. Many processes prefer the lighter (14N) over the heavier (15N) isotope (they 'fractionate'), so the ratios of the two isotopes often differ within and across ecosystems. Our instruments are sufficiently awesome that we can observe these slight variations with great accuracy and precision, and these observations have revealed striking patterns along a number of natural environmental gradients. Because N isotopes integrate processes across time and space, there has been much hope that N isotopic patterns can unlock a mechanistic understanding of N dynamics, particularly at scales that are beyond the reach of experimentation. Is this a realistic hope? Certain patterns have clear, theory-based mechanistic implications. For example, the equilibrium (synonymous here with 'steady-state') isotopic signature of bulk soil N relative to net ecosystem N inputs indicates the degree of isotopic fractionation during ecosystem N losses. However, the nitrogen cycle is sufficiently complex that a given pattern could be produced from a variety of mechanisms, and in such cases it would be easy to infer a mechanism incorrectly. To expand our ability to make mechanistic inferences from N isotopic patterns, I extended a mathematical model of ecosystem N biogeochemistry to include explicit representations of the two N isotopes, constrained the theory with fractionation data, and analyzed the model using analytical approximations and numerical simulations. In this talk I will confine discussion to the submodel that studies ammonium and nitrate. The first three results I will discuss concern transient (non-equilibrium) dynamics, and serve as cautions for equilibrium-based interpretations. First, the time it takes to approach equilibrium is longer for N isotopic ratios than for the corresponding N pools, often by many fold, so isotopic ratios might be far from equilibrium even if pools are close. Second, the approach to equilibrium is often slower from above than below, so the average of measurements through time can be biased relative to the equilibrium. Third, the time it takes to approach equilibrium is shorter when N limits the processes of interest, often by an order of magnitude. In each of these cases, equilibrium-based inferences could be biased, but these results give guidance on the degree of bias and the circumstances under which is it expected, and thus give the ability to adjust equilibrium-based inferences accordingly. With these potential biases in mind, equilibrium results from the model yield mechanistic insights. For example, if some fractionation factors are known, data on N isotopic ratios in ammonium and nitrate allow estimates of the relative strengths of denitrification versus hydrologic nitrate loss. As another example, nitrification can be estimated from data on N isotopic ratios in ammonium and bulk soil N along with some fractionation factors. In this talk I will discuss these insights as they relate to N dynamics along natural environmental gradients.

Menge, D.

2013-12-01

323

A Transient Model of Induced Natural Circulation Thermal Cycling for Hydrogen Isotope Separation  

SciTech Connect

The property of selective temperature dependence of adsorption and desorption of hydrogen isotopes by palladium is used for isotope separation. A proposal to use natural circulation of nitrogen to alternately heat and cool a packed bed of palladium coated beads is under active investigation, and a device consisting of two interlocking natural convection loops is being designed. A transient numerical model of the device has been developed to aid the design process. It is a one-dimensional finite-difference model, using the Boussinesq approximation. The thermal inertia of the pipe walls and other heat structures as well as the heater control logic is included in the model. Two system configurations were modeled and results are compared.

SHADDAY, MARTIN

2005-07-12

324

Acetylation and glycation of fibrinogen in vitro occur at specific lysine residues in a concentration dependent manner: A mass spectrometric and isotope labeling study  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Fibrinogen was incubated in vitro with glucose or aspirin. Black-Right-Pointing-Pointer Acetylations and glycations were found at twelve lysine sites by mass spectrometry. Black-Right-Pointing-Pointer The labeling by aspirin and glucose occurred dose-dependently. Black-Right-Pointing-Pointer No competition between glucose and aspirin for binding to fibrinogen was found. -- Abstract: Aspirin may exert part of its antithrombotic effects through platelet-independent mechanisms. Diabetes is a condition in which the beneficial effects of aspirin are less prominent or absent - a phenomenon called 'aspirin resistance'. We investigated whether acetylation and glycation occur at specific sites in fibrinogen and if competition between glucose and aspirin in binding to fibrinogen occurs. Our hypothesis was that such competition might be one explanation to 'aspirin resistance' in diabetes. After incubation of fibrinogen in vitro with aspirin (0.8 mM, 24 h) or glucose (100 mM, 5-10 days), we found 12 modified sites with mass spectrometric techniques. Acetylations in the {alpha}-chain: {alpha}K191, {alpha}K208, {alpha}K224, {alpha}K429, {alpha}K457, {alpha}K539, {alpha}K562, in the {beta}-chain: {beta}K233, and in the {gamma}-chain: {gamma}K170 and {gamma}K273. Glycations were found at {beta}K133 and {gamma}K75, alternatively {gamma}K85. Notably, the lysine 539 is a site involved in FXIII-mediated cross-linking of fibrin. With isotope labeling in vitro, using [{sup 14}C-acetyl]salicylic acid and [{sup 14}C]glucose, a labeling of 0.013-0.084 and 0.12-0.5 mol of acetylated and glycated adduct/mol fibrinogen, respectively, was found for clinically (12.9-100 {mu}M aspirin) and physiologically (2-8 mM glucose) relevant plasma concentrations. No competition between acetylation and glycation could be demonstrated. Thus, fibrinogen is acetylated at several lysine residues, some of which are involved in the cross-linking of fibrinogen. This may mechanistically explain why aspirin facilitates fibrin degradation. We find no support for the idea that glycation of fibrin(ogen) interferes with acetylation of fibrinogen.

Svensson, Jan, E-mail: jan.svensson@ki.se [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden) [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden); Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden); Bergman, Ann-Charlotte [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden)] [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden); Adamson, Ulf [Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden)] [Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden); Blombaeck, Margareta [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden)] [Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital (Solna), SE-171 76 Stockholm (Sweden); Wallen, Hakan; Joerneskog, Gun [Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden)] [Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, SE-182 88 Stockholm (Sweden)

2012-05-04

325

Conformational and thermodynamic effects of naturally occurring base methylations in a ribosomal RNA hairpin of Bacillus stearothermophilus.  

PubMed

The 3'-terminal colicin fragments of 16S ribosomal RNA were isolated from Bacillus stearothermophilus and from its kasugamycin-resistant (ksgA) derivative lacking N6-dimethylation of the two adjacent adenosines in a hairpin loop. The fragment from the ksgA strain still contains a naturally occurring N2-methylguanosine in the loop. An RNA molecule resembling the B. stearothermophilus colicin fragment but without modified nucleosides was synthesized in vitro using a DNA template and bacteriophage T7 RNA polymerase. Proton-NMR spectra of the RNAs were recorded at 500 MHz. The imino-proton resonances of base-paired G and U residues could be assigned on the basis of previous NMR studies of the colicin fragment of Escherichia coli and by a combination of methylation-induced shifts and thermal melting of base pairs. The assignments were partly confirmed by NOE measurements. Adenosine dimethylation in the loop has a distinct conformational effect on the base pairs adjoining the loop. The thermal denaturation melting curve of the enzymatically synthesized RNA fragment was also determined and the transition midpoint (tm) was found to be 73 degrees C at 15 mM Na+. A comparison with previously determined thermodynamic parameters for various colicin fragments demonstrates that base methylations in the loop lead to a relatively strong destabilization of the hairpin helix. In terms of free energy the positive contribution of the methylations are in the order of the deletion of one base pair from the stem. Other data show that recently published free-energy parameters do not apply for certain RNA hairpins. PMID:1690648

Heus, H A; Formenoy, L J; Van Knippenberg, P H

1990-03-10

326

Animal model of naturally occurring bladder cancer: Characterization of four new canine transitional cell carcinoma cell lines  

PubMed Central

Background Development and further characterization of animal models for human cancers is important for the improvement of cancer detection and therapy. Canine bladder cancer closely resembles human bladder cancer in many aspects. In this study, we isolated and characterized four primary transitional cell carcinoma (K9TCC) cell lines to be used for future in vitro validation of novel therapeutic agents for bladder cancer. Methods Four K9TCC cell lines were established from naturally-occurring canine bladder cancers obtained from four dogs. Cell proliferation rates of K9TCC cells in vitro were characterized by doubling time. The expression profile of cell-cycle proteins, cytokeratin, E-cadherin, COX-2, PDGFR, VEGFR, and EGFR were evaluated by immunocytochemistry (ICC) and Western blotting (WB) analysis and compared with established human bladder TCC cell lines, T24 and UMUC-3. All tested K9TCC cell lines were assessed for tumorigenic behavior using athymic mice in vivo. Results Four established K9TCC cell lines: K9TCC#1Lillie, K9TCC#2Dakota, K9TCC#4Molly, and K9TCC#5Lilly were confirmed to have an epithelial-cell origin by morphology analysis, cytokeratin, and E-cadherin expressions. The tested K9TCC cells expressed UPIa (a specific marker of the urothelial cells), COX-2, PDGFR, and EGFR; however they lacked the expression of VEGFR. All tested K9TCC cell lines confirmed a tumorigenic behavior in athymic mice with 100% tumor incidence. Conclusions The established K9TCC cell lines (K9TCC#1Lillie, K9TCC#2Dakota, K9TCC#4Molly, and K9TCC#5Lilly) can be further utilized to assist in development of new target-specific imaging and therapeutic agents for canine and human bladder cancer. PMID:24964787

2014-01-01

327

Effects of Naturally Occurring Aquatic Organic Fractions on 241Am Uptake by Scenedesmus obliquus (Chlorophyceae) and Aeromonas hydrophila (Pseudomonadaceae)  

PubMed Central

Naturally occurring organics were extracted from water collected from Skinface Pond near Aiken, S.C. Organics were separated into four nominal diameter size fractions (I, >0.0183; II, 0.0183 to 0.0032; III, 0.0032 to 0.0009; IV, <0.0009 ?m) by membrane ultrafiltration and introduced into Scenedesmus obliquus and Aeromonas hydrophila cultures to determine their effects on 241Am availability for uptake. Effects on 241Am uptake were determined in actively growing S. obliquus cultures after 96 h of growth and in dense cultures of nongrowing cells after 4 h. Uptake by A. hydrophila was determined after 4 and 24 h in actively growing cultures. All organic fractions stimulated S. obliquus growth, with the most pronounced effects due to larger organic fractions, whereas no apparent growth stimulation of A. hydrophila was observed for any organic fraction. For both long-term and short-term studies, cellular 241Am concentration (picocuries/cell) increased with increasing 241Am concentration for S. obliquus and A. hydrophila. Fraction IV increased 241Am uptake by both S. obliquus and A. hydrophila during 4-h incubations. During 96-h incubations fraction I was flocculated and cosedimented, with S. obliquus and A. hydrophila cells causing an apparent increase in 241Am uptake. Fractions II and III reduced apparent 241Am uptake by S. obliquus as a result of biological dilution caused by increased algal growth due to the organics. Fraction IV caused a reduction in 241Am uptake by S. obliquus not attributable to biological dilution. Organics increased 241Am uptake by A. hydrophila during 4- and 24-h incubations. A. hydrophila also caused flocculation of fraction I during 96-h incubations. PMID:16345193

Giesy, John P.; Paine, Donald

1977-01-01

328

Exposure to low dose of cinnabar (a naturally occurring mercuric sulfide (HgS)) caused neurotoxicological effects in offspring mice.  

PubMed

Cinnabar, a naturally occurring mercuric sulfide (HgS), has long been used in Chinese mineral medicine for more than 2000 years. Although mercury is well-known for its toxicity, whether cinnabar induces neurotoxicity, especially in infants and children, is unknown. The purpose of this study was to explore the neurotoxic effects of low-dose of cinnabar (10 mg/kg/day) on developing mice. The results revealed neurobehavioral defects in F1-C-Cin group, which were associated with Hg accumulation, increased NO(x) levels in whole blood, and Na(+)/K(+)-ATPase activities in brain tissues. F1- and F2-Cin-V groups were found to increase brain Hg contents and prominent neurobehavioral defects compared with F1-C-V group, suggesting that the fetal brain was more susceptible to irreversible effects for cinnabar-induced damage. Moreover, F1- and F2-Cin-Cin groups had severely neurobehavioral dysfunctions, closely correlated with the further alteration of NO(x) levels and Na(+)/K(+)-ATPase activities than F1- and F2-C-Cin groups. Effects in F2-Cin-Cin group were more significant than those in F1-Cin-Cin group. In conclusion, this study demonstrates that exposure to low-dose of cinnabar during the perinatal and developmental stages results in irreversible and severe injuries of the neurotoxicity in offspring, and NO(x) and Na(+)/K(+)-ATPase activities may exist potential and useful biomarkers for neurotoxicity-induced by low-doses of mercuric compounds. PMID:22888198

Huang, Chun-Fa; Hsu, Chuan-Jen; Liu, Shing-Hwa; Lin-Shiau, Shoei-Yn

2012-01-01

329

Infestation of transgenic powdery mildew-resistant wheat by naturally occurring insect herbivores under different environmental conditions.  

PubMed

A concern associated with the growing of genetically modified (GM) crops is that they could adversely affect non-target organisms. We assessed the impact of several transgenic powdery mildew-resistant spring wheat lines on insect herbivores. The GM lines carried either the Pm3b gene from hexaploid wheat, which confers race-specific resistance to powdery mildew, or the less specific anti-fungal barley seed chitinase and ?-1,3-glucanase. In addition to the non-transformed control lines, several conventional spring wheat varieties and barley and triticale were included for comparison. During two consecutive growing seasons, powdery mildew infection and the abundance of and damage by naturally occurring herbivores were estimated under semi-field conditions in a convertible glasshouse and in the field. Mildew was reduced on the Pm3b-transgenic lines but not on the chitinase/glucanase-expressing lines. Abundance of aphids was negatively correlated with powdery mildew in the convertible glasshouse, with Pm3b wheat plants hosting significantly more aphids than their mildew-susceptible controls. In contrast, aphid densities did not differ between GM plants and their non-transformed controls in the field, probably because of low mildew and aphid pressure at this location. Likewise, the GM wheat lines did not affect the abundance of or damage by the herbivores Oulema melanopus (L.) and Chlorops pumilionis Bjerk. Although a previous study has revealed that some of the GM wheat lines show pleiotropic effects under field conditions, their effect on herbivorous insects appears to be low. PMID:21829479

lvarez-Alfageme, Fernando; von Burg, Simone; Romeis, Jrg

2011-01-01

330

Infestation of Transgenic Powdery Mildew-Resistant Wheat by Naturally Occurring Insect Herbivores under Different Environmental Conditions  

PubMed Central

A concern associated with the growing of genetically modified (GM) crops is that they could adversely affect non-target organisms. We assessed the impact of several transgenic powdery mildew-resistant spring wheat lines on insect herbivores. The GM lines carried either the Pm3b gene from hexaploid wheat, which confers race-specific resistance to powdery mildew, or the less specific anti-fungal barley seed chitinase and ?-1,3-glucanase. In addition to the non-transformed control lines, several conventional spring wheat varieties and barley and triticale were included for comparison. During two consecutive growing seasons, powdery mildew infection and the abundance of and damage by naturally occurring herbivores were estimated under semi-field conditions in a convertible glasshouse and in the field. Mildew was reduced on the Pm3b-transgenic lines but not on the chitinase/glucanase-expressing lines. Abundance of aphids was negatively correlated with powdery mildew in the convertible glasshouse, with Pm3b wheat plants hosting significantly more aphids than their mildew-susceptible controls. In contrast, aphid densities did not differ between GM plants and their non-transformed controls in the field, probably because of low mildew and aphid pressure at this location. Likewise, the GM wheat lines did not affect the abundance of or damage by the herbivores Oulema melanopus (L.) and Chlorops pumilionis Bjerk. Although a previous study has revealed that some of the GM wheat lines show pleiotropic effects under field conditions, their effect on herbivorous insects appears to be low. PMID:21829479

Alvarez-Alfageme, Fernando; von Burg, Simone; Romeis, Jorg

2011-01-01

331

Repellency of naturally occurring volatile alcohols to fungus gnat Bradysia sp. nr. coprophila (Diptera: Sciaridae) adults under laboratory conditions.  

PubMed

This study, conducted under laboratory conditions, was designed to determine the repellent activity of 10 naturally occurring volatile alcohol constituents against adults of the fungus gnat, Bradysia sp. nr. coprophila (Lintner) (Diptera: Sciaridae). The essential oil constituents were octanoic acid, furfural, acetophenone, benzaldehyde, dimethoxybenzene, borneol, menthol, 1-octen-3-ol, and 7-hydroxycitronellol, and alpha-terpineol. alpha-Terpineol, octanoic acid and furfural were tested at several concentrations, whereas the remaining seven were tested at only one concentration. The essential oil constituents' menthol, 1-octen-3-ol, and borneol displayed the most repellent activity. The mean percentage of fungus gnat adults recovered from the test compound petri dishes associated with the three essential oil constituents was between 6 and 15% compared with between 36 and 50% for the petri dishes with distilled water. The mean +/- SEM number of fungus gnat adults present in the sample compartments associated with menthol (10.4 +/- 2.6), 1-octen-3-ol (18.8 +/- 2.4), and borneol (23.4 +/- 5.6) was statistically lower than those in the petri dishes containing distilled water (60.9 +/- 7.4, 49.8 +/- 4.0, and 79.7 +/- 13.5), respectively. Only the highest concentration of alpha-terpineol (8.0 micromol) displayed significant repellent activity against fungus gnat adults. The other essential constituents tested, including octanoic acid (all three concentrations), furfural (both concentrations), acetophenone, dimethoxybenzene, and 7-hydroxycitronellol, were not statistically different from the distilled water control. The results of this study indicate that certain essential oil constituents repel fungus gnat adults, which may be useful, from a practical standpoint, in deterring adults from laying eggs into growing media. PMID:22066193

Cloyd, Raymond A; Marley, Karen A; Larson, Richard A; Dickinson, Amy; Arieli, Bari

2011-10-01

332

Exposure to Low Dose of Cinnabar (a Naturally Occurring Mercuric Sulfide (HgS)) Caused Neurotoxicological Effects in Offspring Mice  

PubMed Central

Cinnabar, a naturally occurring mercuric sulfide (HgS), has long been used in Chinese mineral medicine for more than 2000 years. Although mercury is well-known for its toxicity, whether cinnabar induces neurotoxicity, especially in infants and children, is unknown. The purpose of this study was to explore the neurotoxic effects of low-dose of cinnabar (10?mg/kg/day) on developing mice. The results revealed neurobehavioral defects in F1-C-Cin group, which were associated with Hg accumulation, increased NOx levels in whole blood, and Na+/K+-ATPase activities in brain tissues. F1- and F2-Cin-V groups were found to increase brain Hg contents and prominent neurobehavioral defects compared with F1-C-V group, suggesting that the fetal brain was more susceptible to irreversible effects for cinnabar-induced damage. Moreover, F1- and F2-Cin-Cin groups had severely neurobehavioral dysfunctions, closely correlated with the further alteration of NOx levels and Na+/K+-ATPase activities than F1- and F2-C-Cin groups. Effects in F2-Cin-Cin group were more significant than those in F1-Cin-Cin group. In conclusion, this study demonstrates that exposure to low-dose of cinnabar during the perinatal and developmental stages results in irreversible and severe injuries of the neurotoxicity in offspring, and NOx and Na+/K+-ATPase activities may exist potential and useful biomarkers for neurotoxicity-induced by low-doses of mercuric compounds. PMID:22888198

Huang, Chun-Fa; Hsu, Chuan-Jen; Liu, Shing-Hwa; Lin-Shiau, Shoei-Yn

2012-01-01

333

Lithium isotopes in large rivers reveal the cannibalistic nature of modern continental weathering and erosion  

NASA Astrophysics Data System (ADS)

The erosion of major mountain ranges is thought to be largely cannibalistic, recycling sediments that were deposited in the ocean or on the continents prior to mountain uplift. Despite this recognition, it has not yet been possible to quantify the amount of recycled material that is presently transported by rivers to the ocean. Here, we have analyzed the Li content and isotope composition (?Li7) of suspended sediments sampled along river depth profiles and bed sands in three of the largest Earth's river systems (Amazon, Mackenzie and Ganga-Brahmaputra rivers). The ?Li7 values of river-sediments transported by these rivers range from +5.3 to -3.6 and decrease with sediment grain size. We interpret these variations as reflecting a mixture of unweathered rock fragments (preferentially transported at depth in the coarse fraction) and present-day weathering products (preferentially transported at the surface in the finest fraction). Only the finest surface sediments contain the complementary reservoir of Li solubilized by water-rock interactions within the watersheds. Li isotopes also show that river bed sands can be interpreted as a mixture between unweathered fragments of igneous and sedimentary rocks. A mass budget approach, based on Li isotopes, Li/Al and Na/Al ratios, solved by an inverse method allows us to estimate that, for the large rivers analyzed here, the part of solid weathering products formed by present-day weathering reactions and transported to the ocean do not exceed 35%. Li isotopes also show that the sediments transported by the Amazon, Mackenzie and Ganga-Brahmaputra river systems are mostly sourced from sedimentary rocks (>60%) rather than igneous rocks. This study shows that Li isotopes in the river particulate load are a good proxy for quantifying both the erosional rock sources and the fingerprint of present-day weathering processes. Overall, Li isotopes in river sediments confirm the cannibalistic nature of erosion and weathering.

Dellinger, Mathieu; Gaillardet, Jrme; Bouchez, Julien; Calmels, Damien; Galy, Valier; Hilton, Robert G.; Louvat, Pascale; France-Lanord, Christian

2014-09-01

334

Coupled sulfur and oxygen isotope insight into bacterial sulfate reduction in the natural environment  

NASA Astrophysics Data System (ADS)

We present new sulfur and oxygen isotope data in sulfate (?34SSO4 and ?18OSO4, respectively), from globally distributed marine and estuary pore fluids. We use this data with a model of the biochemical steps involved in bacterial sulfate reduction (BSR) to explore how the slope on a ?18OSO4 vs. ?34SSO4 plot relates to the net sulfate reduction rate (nSRR) across a diverse range of natural environments. Our data demonstrate a correlation between the nSRR and the slope of the relative evolution of oxygen and sulfur isotopes (?18OSO4 vs. ?34SSO4) in the residual sulfate pool, such that higher nSRR results in a lower slope (sulfur isotopes increase faster relative to oxygen isotopes). We combine these results with previously published literature data to show that this correlation scales over many orders of magnitude of nSRR. Our model of the mechanism of BSR indicates that the critical parameter for the relative evolution of oxygen and sulfur isotopes in sulfate during BSR in natural environments is the rate of intracellular sulfite oxidation. In environments where sulfate reduction is fast, such as estuaries and marginal marine environments, this sulfite reoxidation is minimal, and the ?18OSO4 increases more slowly relative to the ?34SSO4. In contrast, in environments where sulfate reduction is very slow, such as deep sea sediments, our model suggests sulfite reoxidation is far more extensive, with as much as 99% of the sulfate being thus recycled; in these environments the ?18OSO4 increases much more rapidly relative to the ?34SSO4. We speculate that the recycling of sulfite plays a physiological role during BSR, helping maintain microbial activity where the availability of the electron donor (e.g. available organic matter) is low.

Antler, Gilad; Turchyn, Alexandra V.; Rennie, Victoria; Herut, Barak; Sivan, Orit

2013-10-01

335

Chemical stability of aai fruit ( Euterpe oleracea Mart.) anthocyanins as influenced by naturally occurring and externally added polyphenolic cofactors in model systems  

Microsoft Academic Search

The influence of different classes of naturally occurring and externally added polyphenolic cofactors on the phytochemical and colour stability of anthocyanins in aai fruit (Euterpe oleracea) was investigated. Model systems were based on anthocyanin isolates from aai fruit, rich in cyanidin-3-rutinoside (31127mg\\/l) and cyanidin-3-glucoside (20818mg\\/l), and isolated groups of naturally occurring polyphenolic cofactors in aai fruit (phenolic acids, procyanidins, and

Lisbeth A. Pacheco-Palencia; Stephen T. Talcott

2010-01-01

336

Characterization of Naturally Occurring and Lamivudine-Induced Surface Gene Mutants of Hepatitis B Virus in Patients with Chronic Hepatitis B in India  

Microsoft Academic Search

Background: Besides vaccine escape or immune escape hepatitis B virus (HBV) mutants, naturally occurring and drug-induced mutations have been reported in the surface gene (S-gene) of HBV. Aim: To investigate the frequency and profile of naturally occurring S-gene mutants and the influence of long-term lamivudine therapy in patients with chronic hepatitis B (CHB). Materials and Methods: 57 patients with histologically

Syed Naqui Kazim; Shiv Kumar Sarin; Barjesh Chander Sharma; Luqman Ahmad Khan; Seyed Ehtesham Hasnain

2006-01-01

337

Measurements of CO2 Carbon Stable Isotopes at Artificial and Natural Analog Sites  

NASA Astrophysics Data System (ADS)

Carbon storage in geologic formations is one method to prevent carbon dioxide (CO2), produced by fossil fuel combustion, from entering the Earth's atmosphere. The monitoring, verification and accounting (MVA) of geologically sequestered CO2 is critical to the operation of a geologic storage site. Surface MVA techniques need to identify seepage from the sequestration reservoir at or below ambient CO2 concentrations. The CO2 carbon stable isotope ratio of is a sensitive diagnostic signature that can distinguish between anthropogenic and natural sources of CO2. Frequency Modulated spectroscopy (FMS) is an ultra-sensitive version of absorption spectroscopy that is capable of detecting the CO2 carbon stable isotope ratios. The technique involves phase modulation of the laser such that two side bands, spaced wider than the absorption feature of interest (in this case +/-2 GHz) are created. The signal is mixed with the local oscillator yielding a signal proportional to the species concentration. This FMS signature is recorded at multiple wavelengths to obtain the CO2 carbon isotope ratio.Two instruments using the FMS technique have been built and tested at LANL. One instrument draws ambient air into a multi-pass cell for a measurement, point source measurements. The other instrument uses an open-air path, tested up to 160 m (round trip), to measure the CO2 carbon isotopic ratio along the beam path, column average measurements. In this paper, results from multiple field deployments of one or both of the instruments will be presented. The Zero Emissions Research & Technology (ZERT) group at Montana State University established a field test site where controlled amounts of CO2 are released to test the performance of CO2 detection instruments and measurement techniques. The field site allows a controlled flow rate of CO2 to be released into the near surface through a 100 m long horizontal pipe. In July of 2009, a release was conducted, with a uniform flow rate of 0.2 tons per day, as the subsequent seepage was measured. There was a similar release, but at a flow rate of 0.15 tons/day, in July 2010. Stable isotope measurements have also been made at several natural analog sites. Two places of interest are the Valles Caldera National Preserve in NM and Soda Springs, ID. The Valle traps CO2 at night and can have very large swings in concentrations that test the instrument range. Soda Springs, ID has many carbonated natural springs and carbon isotope information from this site can provide information regarding CO2 from the deep subsurface, useful for future MVA work.

Humphries, S. D.; Clegg, S. M.; Rahn, T.; Fessenden, J. E.; Dobeck, L.; Spangler, L.; McLing, T. L.

2010-12-01

338

Characterization of the National Petroleum Reserve No. 3 (NPR-3) Site for Naturally Occurring Radioactive Material(NORM)  

SciTech Connect

The National Petroleum Reserve No. 3 site (NPR-3) near Casper, Wyoming is being prepared for transfer to private industry. Remediation of the NPR-3 site has already begun in anticipation of this transfer. This document describes the characterization of the NPR-3 site for Naturally Occurring Radioactive Materials (NORM). Data generated on radionuclide concentrations and radon emanation may be used to determine disposal options and the need for remediation at this site. A preliminary gamma survey of the NPR-3 site was conducted to identify areas of potential NORM contamination. Based on these gamma surveys, two general areas of NORM contamination were found: the North Water Flood area and the BTP-10 produced water discharge steam. A maximum surface exposure rate of 120 {micro}R h{sup -1} was observed in the North Water Flood area, with the highest readings found along the drainage channel from the area. Exposure rates dropped to background quickly with increasing distance from the center of the drainage. The maximum observed exposure rate in the BTP-10 produced water drainage was 40 {micro}R h{sup -1}. Soil and sediment sampling were concentrated in these two areas. All samples were analyzed for concentration of {sup 226}Ra, {sup 228}Ra, and {sup 40}K. Maximum {sup 226}Ra concentrations observed in the samples collected were 46 pCi g{sup -1} for soil and 78 pCi g{sup -1} for sediment. Concentrations in most samples were considerably lower than these values. Radon emanation fraction was also measured for a randomly selected fraction of the samples. The mean Rn emanation fraction measured was 0.10, indicating that on average only 10 percent of the Rn produced is released from the medium. Based on the results of these analyses, NORM contamination at the NPR-3 site is minimal, and appears to be restricted to the two general areas sampled. Concentrations of NORM radionuclides found soils and sediments in these two locations do not justify remedial actions at present. However, continued discharge of NORM-contaminated produced waters from the BTP-10 area will likely result in the continued accumulation of NORM in sediment. It is therefore recommended that the sediments in the BTP-10 discharge stream be monitored periodically for NORM.

White, G.J; Rood, A.S.

1999-01-21

339

Naturally occurring IgG antibody levels to the Staphylococcus aureus protein IsdB in humans  

PubMed Central

Staphylococcus aureus is a well-recognized, clinically important cause of nosocomial infections, and as such, a vaccine to prevent S. aureus infections would be an important achievement. A Phase IIB/III study of V710, a vaccine containing iron-regulated surface determinant B (IsdB), demonstrated significant sero-conversion rates in cardiovascular surgery patients following a single pre-surgery immunization. However, the vaccine was not efficacious in preventing bacteremia or deep sternal wound infection post-surgery, thus raising the possibility that IsdB might not be available for immune recognition during infection. The purpose of the work described herein was to evaluate and quantify the naturally occurring anti-IsdB levels at baseline and over time during infection, to understand whether IsdB is expressed during a S. aureus infection in hospitalized non-vaccinated patients. We evaluated baseline and follow-up titers in 3 populations: (1) healthy subjects, (2) hospitalized patients with non-S. aureus infections, and (3) hospitalized patients with S. aureus infections. Baseline anti-IsdB levels generally overlapped between the 3 groups, but were highly variable within each group. In healthy subjects, baseline and follow-up levels were highly correlated (Spearman's rho = 0.93), and the geometric mean fold-rise (GMFR) in anti-IsdB levels between study entry and last value was 0.9-fold (95% confidence interval (CI): 0.8 to 1.0 ; p = 0.09), showing no trend over time. The convalescent GMFR in anti-IsdB levels from baseline was 1.7-fold (95% CI: 1.3 to 2.2, p = 0.0008) during S. aureus infection, significantly different from the 1.0-fold GMFR (95% CI: 0.91.2, p = 0.60) in non-S. aureus infection, p = 0.005. Additionally, S. aureus isolates (51) obtained from the hospitalized patient group expressed the IsdB protein in vitro. Collectively, these data suggest that IsdB expression levels rise substantially following infection with S. aureus, but not with other pathogens, and IsdB is likely well-conserved across S. aureus strains. PMID:23778314

Zorman, Julie K; Esser, Mark; Raedler, Michael; Kreiswirth, Barry N; Ala'aldeen, Dlawer AA; Kartsonis, Nicholas; Smugar, Steven S; Anderson, Annaliesa S; McNeely, Tessie; Arduino, Jean Marie

2013-01-01

340

In-Situ Sampling and Characterization of Naturally Occurring Marine Methane Hydrate Using the D/V JOIDES Resolution  

SciTech Connect

Cooperative Agreement DE-FC26-01NT41329 between Joint Oceanographic Institutions and DOE-NETL was divided into two phases based on successive proposals and negotiated statements of work pertaining to activities to sample and characterize methane hydrates on ODP Leg 204 (Phase 1) and on IODP Expedition 311 (Phase 2). The Phase 1 Final Report was submitted to DOE-NETL in April 2004. This report is the Phase 2 Final Report to DOE-NETL. The primary objectives of Phase 2 were to sample and characterize methane hydrates using the systems and capabilities of the D/V JOIDES Resolution during IODP Expedition 311, to enable scientists the opportunity to establish the mass and distribution of naturally occurring gas and gas hydrate at all relevant spatial and temporal scales, and to contribute to the DOE methane hydrate research and development effort. The goal of the work was to provide expanded measurement capabilities on the JOIDES Resolution for a dedicated hydrate cruise to the Cascadia continental margin off Vancouver Island, British Columbia, Canada (IODP Expedition 311) so that hydrate deposits in this region would be well characterized and technology development continued for hydrate research. IODP Expedition 311 shipboard activities on the JOIDES Resolution began on August 28 and were concluded on October 28, 2005. The statement of work for this project included three primary tasks: (1) research management oversight, provided by JOI; (2) mobilization, deployment and demobilization of pressure coring and core logging systems, through a subcontract with Geotek Ltd.; and, (3) mobilization, deployment and demobilization of a refrigerated container van that will be used for degassing of the Pressure Core Sampler and density logging of these pressure cores, through a subcontract with the Texas A&M Research Foundation (TAMRF). Additional small tasks that arose during the course of the research were included under these three primary tasks in consultation with the DOE-NETL Program Manager. All tasks outlined in the original statement of work were accomplished except for the deployment and use of the X-ray CT system under Subtask 2-2. This reduction in scope provided resources that were applied to other activities to support the overall project. Post-expedition analysis of results and report writing will continue beyond this reporting period, however, all field deployments associated with this project have been successfully concluded as of this writing.

Frank R. Rack

2006-09-20

341

Naturally occurring IgG antibody levels to the Staphylococcus aureus protein IsdB in humans.  

PubMed

Staphylococcus aureus is a well-recognized, clinically important cause of nosocomial infections, and as such, a vaccine to prevent S. aureus infections would be an important achievement. A Phase IIB/III study of V710, a vaccine containing iron-regulated surface determinant B (IsdB), demonstrated significant sero-conversion rates in cardiovascular surgery patients following a single pre-surgery immunization. However, the vaccine was not efficacious in preventing bacteremia or deep sternal wound infection post-surgery, thus raising the possibility that IsdB might not be available for immune recognition during infection. The purpose of the work described herein was to evaluate and quantify the naturally occurring anti-IsdB levels at baseline and over time during infection, to understand whether IsdB is expressed during a S. aureus infection in hospitalized non-vaccinated patients. We evaluated baseline and follow-up titers in 3 populations: (1) healthy subjects, (2) hospitalized patients with non-S. aureus infections, and (3) hospitalized patients with S. aureus infections. Baseline anti-IsdB levels generally overlapped between the 3 groups, but were highly variable within each group. In healthy subjects, baseline and follow-up levels were highly correlated (Spearman's rho = 0.93), and the geometric mean fold-rise (GMFR) in anti-IsdB levels between study entry and last value was 0.9-fold (95% confidence interval (CI): 0.8 to 1.0 ; p = 0.09), showing no trend over time. The convalescent GMFR in anti-IsdB levels from baseline was 1.7-fold (95% CI: 1.3 to 2.2, p = 0.0008) during S. aureus infection, significantly different from the 1.0-fold GMFR (95% CI: 0.9-1.2, p = 0.60) in non-S. aureus infection, p = 0.005. Additionally, S. aureus isolates (51) obtained from the hospitalized patient group expressed the IsdB protein in vitro. Collectively, these data suggest that IsdB expression levels rise substantially following infection with S. aureus, but not with other pathogens, and IsdB is likely well-conserved across S. aureus strains. PMID:23778314

Zorman, Julie K; Esser, Mark; Raedler, Michael; Kreiswirth, Barry N; Ala'Aldeen, Dlawer A A; Kartsonis, Nicholas; Smugar, Steven S; Anderson, Annaliesa S; McNeely, Tessie; Arduino, Jean Marie

2013-09-01

342

Cr Stable Isotopes in Snake River Plain Aquifer Groundwater: Evidence for Natural Reduction of Dissolved Cr(VI)  

SciTech Connect

At Idaho National Laboratory, Cr(VI) concentrations in a groundwater plume once exceeded regulatory limits in some monitoring wells but have generally decreased over time. This study used Cr stable isotope measurements to determine if part of this decrease resulted from removal of Cr(VI) via reduction to insoluble Cr(III). Although waters in the study area contain dissolved oxygen, the basalt host rock contains abundant Fe(II) and may contain reducing microenvironments or aerobic microbes that reduce Cr(VI). Insomecontaminated locations, 53Cr/52Cr ratios are close to that of the contaminant source, indicating a lack of Cr(VI) reduction. In other locations, ratios are elevated. Part of this shift may be caused by mixing with natural background Cr(VI), which is present at low concentrations but insomelocations has elevated 53Cr/52Cr.Somecontaminated wells have 53Cr/52Cr ratios greater than the maximum attainable by mixing between the inferred contaminant and the range of natural background observed in several uncontaminated wells, suggesting that Cr(VI) reduction has occurred. Definitive proof of reduction would require additional evidence. Depth profiles of 53Cr/52Cr suggest that reduction occurs immediately below the water table, where basalts are likely least weathered and most reactive, and is weak or nonexistent at greater depth.

Amanda L. Raddatz; Thomas M. Johnson; Travis L. McLing

2011-01-01

343

Mass-dependent cadmium isotopic variations in nature with emphasis on the marine environment  

NASA Astrophysics Data System (ADS)

We report a survey of natural mass-dependent cadmium isotope fractionation measured by thermal ionization mass spectrometry using a double-spike technique (DS-TIMS). Over sixty samples of natural terrestrial Cd from diverse environments, including MORB, OIB, continental loess, hydrogenic and hydrothermal ferromanganese deposits, and sphalerites (both oceanic and from major continental ore deposits) were analysed. Our results are expressed in terms of ? 112/110Cd, which are deviations in 112Cd/ 110Cd from our in-house JMC Cd standard in parts per 10 4. The total ? 112/110Cd variation is relatively small, with a range of only 5 ?-units, and is one-to-two orders of magnitude smaller than that previously found in meteorites. The MORB, OIB and loess ? 112/110Cd values are similar and provide a good estimate for the bulk silicate Earth (BSE) value which is - 0.95 0.12 relative to our Cd standard (? 112/110Cd = + 0.16 relative to Mnster JMC Cd). Taken together, these data suggest little Cd isotope fractionation takes place during crust-mantle segregation. Cd isotopic compositions of continental sphalerite (ZnS) deposits worldwide and high-temperature oceanic hydrothermal sulphides show remarkably similar ? 112/110Cd values, consistent with our estimate for the BSE. In contrast, mid-temperature oceanic sulphides from a single extinct hydrothermal chimney display over 4 ?-units variation along with the most negative values. These variations are most probably caused by precipitation/redissolution of sulphide phases en route within the hydrothermal system. The ? 112/110Cd variability found in worldwide marine Fe-Mn deposits reflects the seawater Cd isotope signal upon precipitation from ambient seawater. A decrease in ? 112/110Cd is observed in passing from shallow-water Fe-Mn deposits to those from deeper waters (> 2000 m depth). This shift is explained by biological fractionation related to the uptake of dissolved seawater Cd by phytoplankton in the upper water column. The relatively uniform ? 112/110Cd values close to zero at great depths are consistent with regeneration and remineralization of Cd at depth. Our data suggest that Cd isotopes - much like the Cd/Ca ratio in foraminifera - could potentially serve as a proxy for past changes in biological productivity. The temporal Cd isotope record in a Fe-Mn crust archive at 2000 m depth from the NE Atlantic suggests no gross long-term changes in Cd cycling took place over the past 8 Ma.

Schmitt, Anne-Dsire; Galer, Stephen J. G.; Abouchami, Wafa

2009-01-01

344

Oxygen isotope signatures of transpired water vapor - the role of isotopic non-steady-state transpiration of Mediterranean cork-oaks (Quercus suber L.)under natural conditions  

NASA Astrophysics Data System (ADS)

Oxygen isotope signatures of transpired water vapor (?T) are a powerful tracer of water movement from plants to the global scale, but little is known on short-term variability of ?T as direct high-frequency measurements are lacking. A laser spectrometer was coupled to a gas-exchange chamber directly estimating branch-level fluxes and ?T to evaluate a modeling approach and investigate the role of isotopic non-steady-state transpiration under natural conditions in distinct seasons in cork-oaks (Quercus suber L.). The isotope signature of transpiration (?T) always deviated from steady-state predictions (?T) throughout most of the day even when leaf water at the evaporating sites is near isotopic steady-state. Thus, ?T is further amplified compared to deviations of leaf water isotopes from steady-state, specifically in dry conditions. High agreement was found for direct estimates and modeled ?T assuming non-steady-state conditions of leaf-water at the evaporating sites. Strong isoforcing on the atmosphere of transpiration in isotopic non-steady-state imply that short-term variations in ?T have likely consequences for large-scale applications, e.g. partitioning of ecosystem evapotranspiration or carbon fluxes using C18O16O, or satellite-based applications.

Dubbert, Maren; Piayda, Arndt; Cuntz, Matthias; Werner, Christiane

2014-05-01

345

Determination of organic milk authenticity using carbon and nitrogen natural isotopes.  

PubMed

Natural stable isotopes of carbon and nitrogen ((12)C, (13)C, (14)N, (15)N) have abundances unique to each living creature. Therefore, measurement of the stable isotope ratio of carbon and nitrogen (?(13)C=(13)C/(12)C, ?(15)N=(15)N/(14)N) in milk provides a reliable method to determine organic milk (OM) authenticity. In the present study, the mean ?(13)C value of OM was higher than that of conventional milk (CM), whereas the mean ?(15)N value of OM was lower than that of CM; nonetheless both ?(13)C and ?(15)N values were statistically different for the OM and CM (P<0.05). Furthermore, the values of ?(13)C and ?(15)N were found to differ statistically with the collection date and the milk brand (P<0.05). The combination of ?(13)C and ?(15)N values was more effective than either value alone in distinguishing between OM and CM. The results of the present study, which is based on preliminary data from a limited sample size and sampling period, could be highly valuable and helpful for consumers, the food industry, and/or government regulatory agencies as it can prevent fraudulent labelling of organic food. Further studies include additional analyses of other milk brands and analyses over longer time periods in order to accurately determine OM authenticity using stable isotopes of carbon and nitrogen. PMID:24799230

Chung, Ill-Min; Park, Inmyoung; Yoon, Jae-Yeon; Yang, Ye-Seul; Kim, Seung-Hyun

2014-10-01

346

Assessing the role of trichloroacetyl-containing compounds in the natural formation of chloroform using stable carbon isotopes analysis.  

PubMed

Chloroform (CHCl(3)) is an environmental contaminant widely distributed around world, as well as a natural compound formed in various aquatic and terrestrial environments. However, the chemical mechanisms leading to the natural formation of chloroform in soils are not completely understood. To assess the role of trichloroacetyl-containing compound (TCAc) in the natural formation of chloroform in forest soils, carbon stable isotope analyses of chloroform and TCAc in field samples and chlorination experiments were carried out. The isotope analysis of field samples have revealed that the ?(13)C value of natural chloroform (?(13)C(mean)=-25.8) is in the same range as the natural organic matter (?(13)C(mean)=-27.7), whereas trichloromethyl groups of TCAc are much more enriched in (13)C (?(13)C(mean)=-9.8). A similar relationship was also observed for TCAc and chloroform produced by chlorination of natural organic matter with NaOCl. The strong depletion of (13)C in chloroform relative to TCAc can be explained by carbon isotope fractionation during TCAc hydrolysis. As shown using a mathematical model, when steady state between formation of TCAc and hydrolysis is reached, the isotope ratio of chloroform is expected to correspond to isotope composition of NOM while TCAc should be enriched in (13)C by about 18.3, which is in good agreement with field observations. Hence this study suggests that TCAc are likely precursors of chloroform and at the same time explains why natural chloroform has a similar isotope composition as NOM despite large carbon isotope fractionation during its release. PMID:22925426

Breider, Florian; Albers, Christian Nyrop; Hunkeler, Daniel

2013-01-01

347

Naturally occurring reactive sulfur species, their activity against Caco-2 cells, and possible modes of biochemical action  

Microsoft Academic Search

Natural sulfur compounds from plants, bacteria, fungi, and animals frequently exhibit interesting biological activities, such as antioxidant, antimicrobial, and anticancer activity. Considering the recent developments in medicine (e.g. oxidative stress in aging, antibiotic resistant bacteria, selective anticancer agents) and agriculture (e.g. green pesticides), several of these compounds have become the focus of interdisciplinary research. Among the various sulfur agents isolated

Awais Anwar; Torsten Burkholz; Christiane Scherer; Muhammad Abbas; Claus-Michael Lehr; Marc Diederich; Claus Jacob

2008-01-01

348

Tracing sewage and natural freshwater input in a Northwest Mediterranean bay: Evidence obtained from isotopic ratios in marine organisms  

Microsoft Academic Search

Elemental carbon and nitrogen levels and isotope ratios were assessed in different biological compartments of a Northwest (NW) Mediterranean bay to trace the various sources of nutrient input from natural (river runoffs) and anthropogenic (harbor outflows, fish farms and urban sewage outfall) sources. Samples from transplanted mussels and natural sea grass communities (Posidonia oceanica leaves and epiphytes) were harvested from

J. Lassauque; G. Lepoint; T. Thibaut; P. Francour; A. Meinesz

2010-01-01

349

Neurophysiological Effects of Naturally Occurring Defensive Compounds on the Freshwater Snail Planorbis corneus : Comparison with Effects in Insects  

Microsoft Academic Search

The essential oil constituents citral, geraniol, and eugenol have toxic or repellent properties that are utilized by a variety\\u000a of organisms to deter natural enemies. Their mechanism of action is unknown, but some essential oils such as eugenol are claimed\\u000a to act on insects by specific binding to octopamine receptors. We studied their effects on the isolated buccal ganglia of

David N. Price; Michael S. Berry

2008-01-01

350

Development of naturally occurring siliceous material for the preferential removal of thorium from UTh from aquatic environment  

Microsoft Academic Search

During this work highly particle reactive nature of thorium was exploited for the separation of Th from aquatic stream containing\\u000a U\\/Th. The Kd value of Th(IV) ions is 106 which is two order of magnitude higher than uranium (IV & VI). Laboratory simulated experiments were conducted to study the\\u000a preferential removal of thorium by using siliceous material having particle size

H. Basu; R. K. Singhal; M. V. Pimple; V. Manisha; M. K. T. Bassan; A. V. R. Reddy; T. Mukherjee

2011-01-01

351

Hydrochemistry and boron isotopes as natural tracers in the study of groundwaters from North Chianan Plain, Taiwan.  

PubMed

In this paper, hydrochemistry and boron isotopes are successfully applied to elucidate hydrogeological processes by the use of natural tracers. The hydrochemical analysis identifies four end-members in the hydrochemical evolution of groundwater from the North Chianan plain groundwater district. A few groundwater contain extraordinary chlorine concentrations of up to 48,000mgl(-1). However, the hydrochemistry of groundwater only reveals that high saline water is a dominant factor in groundwater hydrochemistry. It is thought that these groundwater experienced precipitation of carbonates during seawater evaporation that did not involve the precipitation of gypsum. Boron isotopes are very efficient tracers in determining the source of salinisation. The boron isotopes reveal the results of mixing of evaporated seawater and water-sediment interaction. In general, the boron isotope ratio of the groundwater is controlled by a two-end-member mixing system, which is composed of evaporated seawater (isotopically heavy) and fresh surface water (isotopically light). Due to a long lagoonal period in the coastal plain, the groundwaters in the downstream area generally have high Cl/B ratios and relatively heavy boron isotope ratios while those in the upstream area are composed of low Cl/B and light boron isotopes. However, there is not a resolvable mixing trend between the Cl/B ratio and the isotopic composition of boron. It is probably obscured by a highly variable boron isotope ratio in fresh surface water and through fractionation associated with water-rock interaction. Both factors would decrease the boron isotope ratio but one effect cannot be distinguished from the other. PMID:23998391

Lu, Hsueh-Yu

2014-01-01

352

Boron Isotopic Compositions of Near-Surface Fluids: A Tracer for Identification of Natural and Anthropogenic Contaminant Sources  

Microsoft Academic Search

Boron (B) is a sensitive stable isotope tracer which allows identification of different anthropogenic contaminant sources, originating from man-made boron products manufactured from non-marine borates (d11B = +10), in near-surface fluids which are characterized by a different natural background signature of predominantly meteoric origin. The data presented show that the boron isotopic composition of uncontaminated groundwater at the study site

S. R. Barth

2000-01-01

353

Isotopical changes induced by ultrasounds in iron  

NASA Astrophysics Data System (ADS)

As part of a series of experiments based on the application of ultrasound to structural materials and metal alloys, a sample of alpha iron (Ferrite) was subjected to ultrasounds in order to investigate the possible emission of nuclear particles and the possible formation of new isotopes. The sample was subsequently subjected to Instrumental Neutron Activation Analysis (INAA) to highlight the possible transformations that occurred, or the formation of new natural isotopes or the variation of the natural isotopic composition of the material.

Cardone, Fabio; Petrucci, Andrea; Rosada, Alberto

2014-05-01

354

The large bowel carcinogenic effects of hydrazines and related compounds occurring in nature and in the environment.  

PubMed

Five substituted hydrazines that induce large bowel and other types of cancer in laboratory animals are described. Two of these compounds, which originate in nature, are 1,1-dimethylhydrazine, a tobacco ingredient, and methylhydrazine, formed from a chemical present in the edible wild mushroom Gyromitra esculenta. The human population is therefore exposed to them considerably. In addition, both compounds are manufactured and used in rocket fuel. The other three chemicals, 1,2-dimethylhydrazine dihydrochloride,1-methyl-2-butylhydrazine dihydrochloride and trimethylhydrazine hydrochloride, are manufactured synthetically only and apparently are not found in substantial quantities in the environment. PMID:922685

Toth, B

1977-11-01

355

Naturally Occurring Ehrlichia chaffeensis Infection in Two Prosimian Primate Species: Ring-tailed Lemurs (Lemur catta) and Ruffed Lemurs (Varecia variegata)  

Microsoft Academic Search

A naturally occurring infection of Ehrlichia chaffeensis in lemurs is described. DNA of Ehrlichia chaffeensis was identified by polymerase chain reaction in peripheral blood from six of eight clinically ill lemurs. Organisms were cultured from the blood of one lemur exhibiting clinical and hematologic abnormalities similar to those of humans infected with E. chaffeensis.

Cathy V. Williams; Jan L. Van Steenhouse; Julie M. Bradley; Susan I. Hancock; Barbara C. Hegarty; Edward B. Breitschwerdt

356

Both Naturally Occurring Insertions of Transposable Elements and Intermediate Frequency Polymorphisms at the achaete-scute Complex Are Associated With Variation in Bristle Number in Drosophila melanogaster  

Microsoft Academic Search

A restriction enzyme survey of a 110-kb region including the achaete scute complex (ASC) examined 14 polymorphic molecular markers in a sample of 56 naturally occurring chromosomes. Large insertions as a class were associated with a reduction in both sternopleural and abdominal bristle number, supporting deleterious mutation-selection equilibrium models for the maintenance of quantitative genetic variation. Two polymorphic sites were

Anthony D. Long; Richard F. Lyman; Alison H. Morgan; Charles H. Langley; Trudy F. C. Mackay

2000-01-01

357

Raman spectroscopic study of melliteA naturally occurring aluminium benzenehexacarboxylate from ligniteClaystone series of the tertiary age  

NASA Astrophysics Data System (ADS)

Raman spectra have been obtained for crystals of the organic mineral mellite, from three different sites. Mellite occurs in the frame of the Tertiary series including lignite and coaly slates at Artern (Thuringia), Tula (Russia) and Blina (Northern Bohemia). Mellite, Al 2C 6(COO) 616H 2O, can be considered as evidence of previous biological activity in the geological record, similar to other salts of carboxylic acids such as whewellite and weddellite. Assignments of the major Raman features of mellite are proposed on the basis of comparison with the parent, mellitic acid, C 6(COOH) 6. During diagenesis and epigenesis, mellite is formed from the reaction between organic carbon rich solutions with aluminosilicates, hence, with the current interest in the adoption of Raman spectroscopy for incorporation into robotic instrumentation for space mission landers, it is important that organic minerals be included into a spectroscopic database for the recognition of biomolecular signatures for remote life-detection experiments.

Jehlicka, J.; Edwards, H. G. M.; Jorge Villar, S. E.

2006-09-01

358

ISOTOPE HYDROLOGY LABORATORY - RECENT RESEARCH PROJECTS (WATER QUALITY MANAGEMENT BRANCH, WSWRD, NRMRL)  

EPA Science Inventory

The mission of NRMRL's Water Supply and Water Resources Division's Isotope Hydrology Laboratory (IHL) is to resolve environmental hydrology problems through research and application of naturally occurring isotopes. Recent research projects undertaken by IHL include (1) Climate ...

359

Simple Quantitative PCR Approach to Reveal Naturally Occurring and Mutation-Induced Repetitive Sequence Variation on the Drosophila Y Chromosome  

PubMed Central

Heterochromatin is a significant component of the human genome and the genomes of most model organisms. Although heterochromatin is thought to be largely non-coding, it is clear that it plays an important role in chromosome structure and gene regulation. Despite a growing awareness of its functional significance, the repetitive sequences underlying some heterochromatin remain relatively uncharacterized. We have developed a real-time quantitative PCR-based method for quantifying simple repetitive satellite sequences and have used this technique to characterize the heterochromatic Y chromosome of Drosophila melanogaster. In this report, we validate the approach, identify previously unknown satellite sequence copy number polymorphisms in Y chromosomes from different geographic sources, and show that a defect in heterochromatin formation can induce similar copy number polymorphisms in a laboratory strain. These findings provide a simple method to investigate the dynamic nature of repetitive sequences and characterize conditions which might give rise to long-lasting alterations in DNA sequence. PMID:25285439

Aldrich, John C.; Maggert, Keith A.

2014-01-01

360

No-go Theorem for One-way Quantum Computing on Naturally Occurring Two-level Systems  

E-print Network

One-way quantum computing achieves the full power of quantum computation by performing single particle measurements on some many-body entangled state, known as the resource state. As single particle measurements are relatively easy to implement, the preparation of the resource state becomes a crucial task. An appealing approach is simply to cool a strongly correlated quantum many-body system to its ground state. In addition to requiring the ground state of the system to be universal for one-way quantum computing, we also want the Hamiltonian to have non-degenerate ground state protected by a fixed energy gap, to involve only two-body interactions, and to be frustration-free so that measurements in the course of the computation leave the remaining particles in the ground space. Recently, significant efforts have been made to the search of resource states that appear naturally as ground states in spin lattice systems. The approach is proved to be successful in spin-5/2 and spin-3/2 systems. Yet, it remains an open question whether there could be such a natural resource state in a spin-1/2, i.e., qubit system. Here, we give a negative answer to this question by proving that it is impossible for a genuinely entangled qubit states to be a non-degenerate ground state of any two-body frustration-free Hamiltonian. What is more, we prove that every spin-1/2 frustration-free Hamiltonian with two-body interaction always has a ground state that is a product of single- or two-qubit states, a stronger result that is interesting independent of the context of one-way quantum computing.

Jianxin Chen; Xie Chen; Runyao Duan; Zhengfeng Ji; Bei Zeng

2010-04-21

361

Application of Stable Carbon Isotope Ratios to Recognize Natural Biodegradation of MTBE  

EPA Science Inventory

The organisms that degrade MTBE under anaerobic conditions are evolved to acquire energy for growth by using molecular hydrogen and carbonate ion to cleave methyl ether bonds. Methyl ether bonds are common in nature and the bond also occurs in MTBE. MTBE in contaminated ground...

362

Evaluation of a stable isotope method to mark naturally-breeding larval mosquitoes for adult dispersal studies.  

PubMed

Understanding mosquito dispersal is critically important for vector-borne disease control and prevention. Mark-release-recapture methods using various marking techniques have made substantial contributions to the study of mosquito biology. However, the ability to mark naturally breeding mosquitoes noninvasively and with life-long retention has remained problematic. Here, we describe a method to mark naturally breeding mosquitoes with stable isotopes. Culex pipiens f. molestus mosquitoes were provisioned as larvae in laboratory experiments with 15N-labeled potassium nitrate and 13C-labeled glucose. Larval enrichment was sufficient to differentiate marked adult mosquitoes from unmarked control mosquitoes and the natural source population from Chicago Illinois, using either delta 15N or delta 13C. Isotopic retention lasted for at least 55 d for adult male and females mosquitoes. There were no consistent effects of isotopic enrichment on immature mosquito survival or adult mosquito body size. We then applied this marking technique to naturally breeding Culex pipiens mosquitoes in suburban Chicago, IL, and for the first time, report successful isotopic enrichment of mosquitoes in the field. This stable isotope marking technique will facilitate studies of mosquito dispersal. PMID:22308772

Hamer, Gabriel L; Donovan, Danielle J; Hood-Nowotny, Rebecca; Kaufman, Michael G; Goldberg, Tony L; Walker, Edward D

2012-01-01

363

Iron isotope composition of particles produced by UV-femtosecond laser ablation of natural oxides, sulfides, and carbonates.  

PubMed

The need for femtosecond laser ablation (fs-LA) systems coupled to MC-ICP-MS to accurately perform in situ stable isotope analyses remains an open question, because of the lack of knowledge concerning ablation-related isotopic fractionation in this regime. We report the first iron isotope analysis of size-resolved, laser-induced particles of natural magnetite, siderite, pyrrhotite, and pyrite, collected through cascade impaction, followed by analysis by solution nebulization MC-ICP-MS, as well as imaging using electron microscopy. Iron mass distributions are independent of mineralogy, and particle morphology includes both spheres and agglomerates for all ablated phases. X-ray spectroscopy shows elemental fractionation in siderite (C-rich agglomerates) and pyrrhotite/pyrite (S-rich spheres). We find an increase in (56)Fe/(54)Fe ratios of +2, +1.2, and +0.8 with increasing particle size for magnetite, siderite, and pyrrhotite, respectively. Fe isotope differences in size-sorted aerosols from pyrite ablation are not analytically resolvable. Experimental data are discussed using models of particles generation by Hergenrder and elemental/isotopic fractionation by Richter. We interpret the isotopic fractionation to be related to the iron condensation time scale, dependent on its saturation in the gas phase, as a function of mineral composition. Despite the isotopic variations across aerosol size fractions, total aerosol composition, as calculated from mass balance, confirms that fs-LA produces a stoichiometric sampling in terms of isotopic composition. Specifically, both elemental and isotopic fractionation are produced by particle generation processes and not by femtosecond laser-matter interactions. These results provide critical insights into the analytical requirements for laser-ablation-based stable isotope measurements of high-precision and accuracy in geological samples, including the importance of quantitative aerosol transport to the ICP. PMID:24261311

d'Abzac, Francois-Xavier; Beard, Brian L; Czaja, Andrew D; Konishi, Hiromi; Schauer, James J; Johnson, Clark M

2013-12-17

364

A naturally occurring defective DNA satellite associated with a monopartite begomovirus: evidence for recombination between alphasatellite and betasatellite.  

PubMed

Monopartite begomoviruses and their associated satellites form unique disease complexes that have emerged as a serious threat to agriculture worldwide. It is well known that frequent recombination contributes to the diversification and evolution of geminiviruses. In this study, we identified a novel defective satellite molecule (RecSat) in association with Tobacco leaf curl Yunnan virus (TbLCYNV) in a naturally infected tobacco plant. Sequence analysis showed that Recsat comprises 754 nucleotides in size and is a chimera involving alphasatellite and betasatellite sequences, containing both betasatellite-conserved region and alphasatellite stem-loop structure. Recombination analysis revealed that RecSat has arisen from three independent recombination events likely involving Tomato yellow leaf curl China betasatellite, Ageratum yellow vein China betasatellite and Tobacco curly shoot alphasatellite. Co-inoculation of RecSat with TbLCYNV induced symptoms indistinguishable from those induced by TbLCYNV alone in Nicotiana benthamiana. Southern blot hybridization showed that RecSat could be trans-replicated stably in N. benthamiana plants by TbLCYNV, and impaired the accumulation of helper virus and co-inoculated alphasatellite. Our results provide the first evidence for recombination between two distinct types of satellites among geminivirus complex and highlight recombination as a driving force for geminivirus evolution. PMID:24018984

Huang, Changjun; Xie, Yan; Zhao, Liling; Ren, He; Li, Zhenghe

2013-09-01

365

No-go theorem for one-way quantum computing on naturally occurring two-level systems  

SciTech Connect

The ground states of some many-body quantum systems can serve as resource states for the one-way quantum computing model, achieving the full power of quantum computation. Such resource states are found, for example, in spin-(5/2) and spin-(3/2) systems. It is, of course, desirable to have a natural resource state in a spin-(1/2), that is, qubit system. Here, we give a negative answer to this question for frustration-free systems with two-body interactions. In fact, it is shown to be impossible for any genuinely entangled qubit state to be a nondegenerate ground state of any two-body frustration-free Hamiltonian. What is more, we also prove that every spin-(1/2) frustration-free Hamiltonian with two-body interaction always has a ground state that is a product of single- or two-qubit states. In other words, there cannot be any interesting entanglement features in the ground state of such a qubit Hamiltonian.

Chen Jianxin [Department of Computer Science and Technology, Tsinghua National Laboratory for Information Science and Technology, Tsinghua University, Beijing (China); Chen Xie [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); Duan Runyao [Department of Computer Science and Technology, Tsinghua National Laboratory for Information Science and Technology, Tsinghua University, Beijing (China); Centre for Quantum Computation and Intelligent Systems (QCIS), Faculty of Engineering and Information Technology, University of Technology, Sydney, New South Wales (Australia); Ji Zhengfeng [Perimeter Institute for Theoretical Physics, Waterloo, Ontario (Canada); State Key Laboratory of Computer Science, Institute of Software, Chinese Academy of Sciences, Beijing (China); Zeng Bei [Institute for Quantum Computing and Department of Combinatorics and Optimization, University of Waterloo, Waterloo, Ontario (Canada)

2011-05-15

366

Natural isotopic signatures of variations in body nitrogen fluxes: a compartmental model analysis.  

PubMed

Body tissues are generally 15N-enriched over the diet, with a discrimination factor (?15N) that varies among tissues and individuals as a function of their nutritional and physiopathological condition. However, both 15N bioaccumulation and intra- and inter-individual ?15N variations are still poorly understood, so that theoretical models are required to understand their underlying mechanisms. Using experimental ?15N measurements in rats, we developed a multi-compartmental model that provides the first detailed representation of the complex functioning of the body's ?15N system, by explicitly linking the sizes and ?15N values of 21 nitrogen pools to the rates and isotope effects of 49 nitrogen metabolic fluxes. We have shown that (i) besides urea production, several metabolic pathways (e.g., protein synthesis, amino acid intracellular metabolism, urea recycling and intestinal absorption or secretion) are most probably associated with isotope fractionation and together contribute to 15N accumulation in tissues, (ii) the ?15N of a tissue at steady-state is not affected by variations of its P turnover rate, but can vary according to the relative orientation of tissue free amino acids towards oxidation vs. protein synthesis, (iii) at the whole-body level, ?15N variations result from variations in the body partitioning of nitrogen fluxes (e.g., urea production, urea recycling and amino acid exchanges), with or without changes in nitrogen balance, (iv) any deviation from the optimal amino acid intake, in terms of both quality and quantity, causes a global rise in tissue ?15N, and (v) ?15N variations differ between tissues depending on the metabolic changes involved, which can therefore be identified using simultaneous multi-tissue ?15N measurements. This work provides proof of concept that ?15N measurements constitute a new promising tool to investigate how metabolic fluxes are nutritionally or physiopathologically reorganized or altered. The existence of such natural and interpretable isotopic biomarkers promises interesting applications in nutrition and health. PMID:25275306

Poupin, Nathalie; Mariotti, Franois; Huneau, Jean-Franois; Hermier, Dominique; Fouillet, Hlne

2014-10-01

367

Natural Isotopic Signatures of Variations in Body Nitrogen Fluxes: A Compartmental Model Analysis  

PubMed Central

Body tissues are generally 15N-enriched over the diet, with a discrimination factor (?15N) that varies among tissues and individuals as a function of their nutritional and physiopathological condition. However, both 15N bioaccumulation and intra- and inter-individual ?15N variations are still poorly understood, so that theoretical models are required to understand their underlying mechanisms. Using experimental ?15N measurements in rats, we developed a multi-compartmental model that provides the first detailed representation of the complex functioning of the body's ?15N system, by explicitly linking the sizes and ?15N values of 21 nitrogen pools to the rates and isotope effects of 49 nitrogen metabolic fluxes. We have shown that (i) besides urea production, several metabolic pathways (e.g., protein synthesis, amino acid intracellular metabolism, urea recycling and intestinal absorption or secretion) are most probably associated with isotope fractionation and together contribute to 15N accumulation in tissues, (ii) the ?15N of a tissue at steady-state is not affected by variations of its P turnover rate, but can vary according to the relative orientation of tissue free amino acids towards oxidation vs. protein synthesis, (iii) at the whole-body level, ?15N variations result from variations in the body partitioning of nitrogen fluxes (e.g., urea production, urea recycling and amino acid exchanges), with or without changes in nitrogen balance, (iv) any deviation from the optimal amino acid intake, in terms of both quality and quantity, causes a global rise in tissue ?15N, and (v) ?15N variations differ between tissues depending on the metabolic changes involved, which can therefore be identified using simultaneous multi-tissue ?15N measurements. This work provides proof of concept that ?15N measurements constitute a new promising tool to investigate how metabolic fluxes are nutritionally or physiopathologically reorganized or altered. The existence of such natural and interpretable isotopic biomarkers promises interesting applications in nutrition and health. PMID:25275306

Poupin, Nathalie; Mariotti, Francois; Huneau, Jean-Francois; Hermier, Dominique; Fouillet, Helene

2014-01-01

368

The expression of a naturally occurring, truncated allele of an ?-SNAP gene suppresses plant parasitic nematode infection.  

PubMed

Transcriptional mapping experiments of the major soybean cyst nematode resistance locus, rhg1, identified expression of the vesicular transport machinery component, ? soluble NSF attachment protein (?-SNAP), occurring during defense. Sequencing the ?-SNAP coding regions from the resistant genotypes G. max ([Peking/PI 548402]) and G. max ([PI 437654]) revealed they are identical, but differ from the susceptible G. max ([Williams 82/PI 518671]) by the presence of several single nucleotide polymorphisms. Using G. max ([Williams 82/PI 518671]) as a reference, a G?T(2,822) transversion in the genomic DNA sequence at a functional splice site of the ?-SNAP([Peking/PI 548402]) allele produced an additional 17 nucleotides of mRNA sequence that contains an in-frame stop codon caused by a downstream G?A(2,832) transition. The G. max ([Peking/PI 548402]) genotype has cell wall appositions (CWAs), structures identified as forming as part of a defense response by the activity of the vesicular transport machinery. In contrast, the 17 nt ?-SNAP([Peking/PI 548402]) mRNA motif is not found in G. max ([PI 88788]) that exhibits defense to H. glycines, but lack CWAs. The ?-SNAP([PI 88788]) promoter contains sequence elements that are nearly identical to the ?-SNAP([Peking/PI 548402]) allele, but differs from the G. max ([Williams 82/PI 518671]) ortholog. Overexpressing the ?-SNAP([Peking/PI 548402]) allele in the susceptible G. max ([Williams 82/PI 518671]) genotype suppressed H. glycines infection. The experiments indicate a role for the vesicular transport machinery during infection of soybean by the soybean cyst nematode. However, increased GmEREBP1, PR1, PR2, PR5 gene activity but suppressed PR3 expression accompanied the overexpression of the ?-SNAP([Peking/PI 548402]) allele prior to infection. PMID:22689004

Matsye, Prachi D; Lawrence, Gary W; Youssef, Reham M; Kim, Kyung-Hwan; Lawrence, Katheryn S; Matthews, Benjamin F; Klink, Vincent P

2012-09-01

369

Genetic Structure and Wolbachia Genotyping in Naturally Occurring Populations of Aedes albopictus across Contiguous Landscapes of Orissa, India  

PubMed Central

Background Aedes albopictus has recently been implicated as a major vector in the emergence of dengue and chikungunya in several parts of India, like Orissa, which is gradually gaining endemicity for arboviral diseases. Ae. albopictus is further known to be naturally infected with Wolbachia (maternally inherited bacterium), which causes cytoplasmic incompatibility (CI) in mosquitoes leading to sperm-egg incompatibility inducing the death of embryo. Knowledge of genetic diversity of Ae. albopictus, along with revealing the type of Wolbachia infection in Ae. albopictus is important to explore the genetic and biological characteristics of Ae. albopictus, prior to exploring the uses of CI-based vector control strategies. In this study, we assessed the population genetic structure and the pattern of Wolbachia infection in Ae. albopictus mosquitoes of Orissa. Methods and Results Ae. albopictus mosquitoes were collected from 15 districts representing the four physiographical regions of Orissa from 20102012, analyzed for genetic variability at seven microsatellite loci and genotyped for Wolbachia strain detection using wsp gene primers. Most microsatellite markers were successfully amplified and were polymorphic, showing moderate genetic structure among all geographic populations (FST?=?0.088). Genetic diversity was high (FST?=?0.168) in Coastal Plains populations when compared with other populations, which was also evident from cluster analyses that showed most Coastal Plains populations consisted of a separate genetic cluster. Genotyping analyses revealed that Wolbachia-infected Ae. albopictus field populations of Orissa were mostly superinfected with wAlbA and wAlbB strains. Wolbachia superinfection was more pronounced in the Coastal Plain populations. Conclusion High genetic structure and Wolbachia superinfection, observed in the Coastal Plain populations of Orissa suggested it to be genetically and biologically more unique than other populations, and hence could influence their vectorial attributes. Such high genetic diversity observed among Coastal Plains populations could be attributed to multiple introductions of Ae. albopictus in this region. PMID:24714653

Das, Biswadeep; Satapathy, Truptimayee; Kar, Santanu K.; Hazra, Rupenangshu K.

2014-01-01

370

Strain specific resistance to murine scrapie associated with a naturally occurring human prion protein polymorphism at residue 171.  

PubMed

Transmissible spongiform encephalopathies (TSE) or prion diseases are neurodegenerative disorders associated with conversion of normal host prion protein (PrP) to a misfolded, protease-resistant form (PrPres).Genetic variations of prion protein in humans and animals can alter susceptibility to both familial and infectious prion diseases. The N171S PrP polymorphism is found mainly in humans of African descent, but its low incidence has precluded study of its possible influence on prion disease. Similar to previous experiments of others, for laboratory studies we created a transgenic model expressing the mouse PrP homolog, PrP-170S, of human PrP-171S. Since PrP polymorphisms can vary in their effects on different TSE diseases, we tested these mice with four different strains of mouse-adapted scrapie. Whereas 22L and ME7 scrapie strains induced typical clinical disease, neuropathology and accumulation of PrPres in all transgenic mice at 99-128 average days post-inoculation, strains RML and 79A produced clinical disease and PrPres formation in only a small subset of mice at very late times. When mice expressing both PrP-170S and PrP-170N were inoculated with RML scrapie, dominant-negative inhibition of disease did not occur, possibly because interaction of strain RML with PrP-170S was minimal. Surprisingly, in vitro PrP conversion using protein misfolding cyclic amplification (PMCA), did not reproduce the in vivo findings, suggesting that the resistance noted in live mice might be due to factors or conditions not present in vitro. These findings suggest that in vivo conversion of PrP-170S by RML and 79A scrapie strains was slow and inefficient. PrP-170S mice may be an example of the conformational selection model where the structure of some prion strains does not favor interactions with PrP molecules expressing certain polymorphisms. PMID:21980292

Striebel, James F; Race, Brent; Meade-White, Kimberly D; LaCasse, Rachel; Chesebro, Bruce

2011-09-01

371

Strain Specific Resistance to Murine Scrapie Associated with a Naturally Occurring Human Prion Protein Polymorphism at Residue 171  

PubMed Central

Transmissible spongiform encephalopathies (TSE) or prion diseases are neurodegenerative disorders associated with conversion of normal host prion protein (PrP) to a misfolded, protease-resistant form (PrPres).Genetic variations of prion protein in humans and animals can alter susceptibility to both familial and infectious prion diseases. The N171S PrP polymorphism is found mainly in humans of African descent, but its low incidence has precluded study of its possible influence on prion disease. Similar to previous experiments of others, for laboratory studies we created a transgenic model expressing the mouse PrP homolog, PrP-170S, of human PrP-171S. Since PrP polymorphisms can vary in their effects on different TSE diseases, we tested these mice with four different strains of mouse-adapted scrapie. Whereas 22L and ME7 scrapie strains induced typical clinical disease, neuropathology and accumulation of PrPres in all transgenic mice at 99-128 average days post-inoculation, strains RML and 79A produced clinical disease and PrPres formation in only a small subset of mice at very late times. When mice expressing both PrP-170S and PrP-170N were inoculated with RML scrapie, dominant-negative inhibition of disease did not occur, possibly because interaction of strain RML with PrP-170S was minimal. Surprisingly, in vitro PrP conversion using protein misfolding cyclic amplification (PMCA), did not reproduce the in vivo findings, suggesting that the resistance noted in live mice might be due to factors or conditions not present in vitro. These findings suggest that in vivo conversion of PrP-170S by RML and 79A scrapie strains was slow and inefficient. PrP-170S mice may be an example of the conformational selection model where the structure of some prion strains does not favor interactions with PrP molecules expressing certain polymorphisms. PMID:21980292

Striebel, James F.; Race, Brent; Meade-White, Kimberly D.; LaCasse, Rachel; Chesebro, Bruce

2011-01-01

372

In-Situ Sampling and Characterization of Naturally Occurring Marine Methane Hydrate Using the D/V JOIDES Resolution  

SciTech Connect

The primary accomplishment of the JOI Cooperative Agreement with DOE/NETL in this quarter was the deployment of tools and measurement systems on ODP Leg 204 to study hydrate deposits on Hydrate Ridge, offshore Oregon from July through September, 2002. During Leg 204, we cored and logged 9 sites on the Oregon continental margin to determine the distribution and concentration of gas hydrates in an accretionary ridge and adjacent slope basin, investigate the mechanisms that transport methane and other gases into the gas hydrate stability zone (GHSZ), and obtain constraints on physical properties of hydrates in situ. A 3D seismic survey conducted in 2000 provided images of potential subsurface fluid conduits and indicated the position of the GHSZ throughout the survey region. After coring the first site, we acquired Logging-While-Drilling (LWD) data at all but one site to provide an overview of downhole physical properties. The LWD data confirmed the general position of key seismic stratigraphic horizons and yielded an initial estimate of hydrate concentration through the proxy of in situ electrical resistivity. These records proved to be of great value in planning subsequent coring. The second new hydrate proxy to be tested was infrared thermal imaging of cores on the catwalk as rapidly as possible after retrieval. The thermal images were used to identify hydrate samples and to map estimate the distribution and texture of hydrate within the cores. Geochemical analyses of interstitial waters and of headspace and void gases provide additional information on the distribution and concentration of hydrate within the stability zone, the origin and pathway of fluids into and through the GHSZ, and the rates at which the process of gas hydrate formation is occurring. Bio- and lithostratigraphic description of cores, measurement of physical properties, and in situ pressure core sampling and thermal measurements complement the data set, providing ground-truth tests of inferred physical and sedimentological properties. Among the most interesting preliminary results are: (1) the discovery that gas hydrates are distributed through a broad depth range within the GHSZ and that different physical and chemical proxies for hydrate distribution and concentration give generally consistent results; (2) evidence for the importance of sediment properties for controlling the migration of fluids in the accretionary complex; (3) geochemical indications that the gas hydrate system at Hydrate Ridge contains significant concentrations of higher order hydrocarbons and that fractionation and mixing signals will provide important constraints on gas hydrate dynamics; and (4) the discovery of very high chlorinity values that extend for at least 10 mbsf near the summit, indicating that hydrate formation here must be very rapid.

Frank Rack; Gerhard Bohrmann; Anne Trehu; Michael Storms; Derryl Schroeder; ODP Leg 204 Shipboard Scientific Party

2002-09-30

373

Isotopic studies of rare gases in terrestrial samples and natural nucleosynthesis  

SciTech Connect

This project is concerned with research in rare gas mass spectrometry. We read the natural record that isotopes of the rare gases provide. We study fluids using a system (RARGA) that is sometimes deployed in the field. In 1990 there was a strong effort to reduce the backlog of RARGA samples on hand, so that it was a year of intensive data gathering. Samples from five different areas in the western United States and samples from Guatemala and Australia were analyzed. In a collaborative study we also began analyzing noble gases from rocks associated with the fluids. An important objective, continuing in 1991, is to understand better the reasons for somewhat elevated {sup 3}He/{sup 4}He ratios in regions where there is no contemporary volcanism which could produce the effect by addition of mantle helium. Our helium data have given us and our collaborators some insights, which are to be followed up, into gold mineralization in geothermal regions. Our DOE work in calibrating a sensitive laser microprobe mass spectrometer for noble gases in fluid inclusions continues. Having completed a series of papers on noble gases in diamonds, we next will attempt to make precise isotopic measurements on xenon from mantle sources, in search of evidence for terrestrially elusive {sup 244}Pu decay.

Not Available

1990-07-01

374

Naturally occurring sulfonium-ion glucosidase inhibitors and their derivatives: a promising class of potential antidiabetic agents.  

PubMed

In humans, four different enzymes mediate the digestion of ingested carbohydrates. First salivary and pancreatic ?-amylases, the two endoacting retaining glucosidases, break down the complex starch molecules into smaller linear maltose-oligomers (LM) and branched ?-limit dextrins (?LDx). Then two retaining exoglucosidases, maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI), convert those molecules into glucose in the small intestine. The small intestinal brush-border epithelial cells anchor MGAM and SI, and each contains a catalytic N- and C-terminal subunit, ntMGAM, ctMGAM, ntSI, and ctSI, respectively. All four catalytic domains have, to varying extents, ?-1,4-exohydrolytic glucosidase activity and belong to the glycoside hydrolase family 31 (GH31). ntSI and ctSI show additional activity toward ?-1,6 (isomaltose substrates) and ?-1,2 (sucrose) glycosidic linkages, respectively. Because they mediate the final steps of starch digestion, both MGAM and SI are important target enzymes for the treatment of type-2 diabetes. Because of their potent inhibitory activities against the mammalian intestinal ?-glucosidases, sulfonium-ion glucosidase inhibitors isolated from the antidiabetic herbal extracts of various Salacia species have received considerable attention recently. Thus far, researchers have isolated eight sulfonium-ion glucosidase inhibitors from Salacia species: salaprinol, salacinol, ponkoranol, kotalanol, and four of their corresponding de-O-sulfonated compounds, the structures of which comprise a 1,4-anhydro-4-thio-d-arabinitol and a polyhydroxylated acyclic side chain. Some of these compounds more strongly inhibit human intestinal ?-glucosidases than the currently available antidiabetic drugs, acarbose and miglitol, and could serve as lead candidates in the treatment of type-2 diabetes. In this Account, we summarize progress in the field since 2010 with this class of inhibitors, with particular focus on their selective inhibitory activities against the intestinal glucosidases. Through structure-activity relationship (SAR) studies, we have modified the natural compounds to derive more potent, nanomolar inhibitors of human MGAM and SI. This structural optimization also yielded the most potent inhibitors known to date for each subunit. Furthermore, we observed that some of our synthetic inhibitors selectively blocked the activity of some mucosal ?-glucosidases. Those results led to our current working hypothesis that selective inhibitors can dampen the action of a fast digesting subunit or subunits which places the burden of digestion on slower digesting subunits. That strategy can control the rate of starch digestion and glucose release to the body. Decreasing the initial glucose spike after a carbohydrate-rich meal and extending postprandial blood glucose delivery to the body can be desirable for diabetics and patients with other metabolic syndrome-associated diseases. PMID:23964564

Mohan, Sankar; Eskandari, Razieh; Pinto, B Mario

2014-01-21

375

Natural and Anthropogenic Impacts on the Stable Isotopes of Nitrogen and Oxygen of Ice-Core Nitrate  

NASA Astrophysics Data System (ADS)

The stable isotopes of nitrogen and oxygen of the Ross Ice Drainage System (RIDS) ice-core nitrate were measured in approximately 2-3 year time resolution using a Delta V Isotope Ratio Mass Spectrometer (IRMS). The nitrogen isotope variation (?15N) and the mass-independent fractionation of oxygen (?17O = ?17O - 0.52*?18O) yield a detailed picture of the changes in the global nitrogen cycling and the shift in the oxidation capacity of the atmosphere in response to natural and anthropogenic induced climate change. This is one of the few studies on stable isotopes of ice-core nitrate for time periods prior to the 1800's and will increase our understanding of the oxidation feedbacks of the atmosphere in response to volcanic events, the Little Ice Age, the Maunder Minimum, and anthropogenic emissions in the Southern Hemisphere.

Walters, W.; Michalski, G. M.

2013-12-01

376

Age and nature of the basement in northeastern Washington and northern Idaho: isotopic evidence from Mesozoic and Cenozoic granitoids  

USGS Publications Warehouse

K-feldspar Pb and whole rock Nd isotopic analyses from 25 Mesozoic and Cenozoic plutonic rocks and two gneisses from NE Washington and northern Idaho are used to elucidate the age and nature of the concealed cratonic basement. The plutons form two highly distinct isotopic groups: Group I have isotopic compositions suggesting derivation from rocks of the Belt Supergroup or their metamorphosed equivalents, Group II have highly retarded Pb isotopic compositions relative to the present day crustal average and require a source region with long-term U depletion, characteristic of cratonic lower crust. A U-Pb zircon upper intercept age of c2600 Ma obtained from one of the Group II samples, together with Sm-Nd data from the gneisses, indicates possible late-Archean crust at depth, which acted as a source region for Eocene extension-related plutonism. -from Authors

Whitehouse, M.J.; Stacey, J.S.; Miller, F.K.

1992-01-01

377

Negative ion ESI-MS analysis of natural yellow dye flavonoids--An isotopic labelling study  

NASA Astrophysics Data System (ADS)

Flavonoids are amongst the most commonly used natural yellow colourants in paintings, as lakes, and in historical textiles as mordant dyes. In this paper, evidence from isotopically labelled substrates is used to propose negative ion electrospray collision induced decomposition mechanisms of flavones, flavonols and an isoflavone. These mechanisms include a retro-Diels-Alder fragmentation (observed for flavones and flavonols) and an M-122 fragmentation (characteristic of 3',4'-dihydroxyflavonols). In addition, the presence of a m/z 125 fragment ion is shown to be characteristic of 2'-hydroxyflavonols and an ion at m/z 149 is shown to be characteristic of 4'-hydroxyflavones. Applications of these methods are exemplified by the identification of a minor component of Dyer's camomile (Anthemis tinctoria L.) and the identification of the dye source in green threads sampled from an 18th Century Scottish tartan fragment.

McNab, Hamish; Ferreira, Ester S. B.; Hulme, Alison N.; Quye, Anita

2009-07-01

378

Ion exchange separation of chromium from natural water matrix for stable isotope mass spectrometric analysis  

USGS Publications Warehouse

A method has been developed for separating the Cr dissolved in natural water from matrix elements and determination of its stable isotope ratios using solid-source thermal-ionization mass spectrometry (TIMS). The separation method takes advantage of the existence of the oxidized form of Cr as an oxyanion to separate it from interfering cations using anion-exchange chromatography, and of the reduced form of Cr as a positively charged ion to separate it from interfering anions such as sulfate. Subsequent processing of the separated sample eliminates residual organic material for application to a solid source filament. Ratios for 53Cr/52Cr for National Institute of Standards and Technology Standard Reference Material 979 can be measured using the silica gel-boric acid technique with a filament-to-filament standard deviation in the mean 53Cr/52Cr ratio for 50 replicates of 0.00005 or less. (C) 2000 Elsevier Science B.V. All rights reserved.

Ball, J.W.; Bassett, R.L.

2000-01-01

379

HCNMBC - A pulse sequence for H-(C)-N Multiple Bond Correlations at natural isotopic abundance  

NASA Astrophysics Data System (ADS)

We propose a pulse sequence, HCNMBC for multiple-bond H-(C)-N correlation experiments via one-bond 1J(C,H) and one- or multiple bond nJ(N,C) coupling constants (typically n = 1-3) at the natural isotopic abundance. A new adiabatic refocussing sequence is introduced to provide accurate and robust refocussing of both chemical shift and J-evolution over wide ranges of C-13 and N-15 frequencies. It is demonstrated that the proposed pulse sequence provides high quality spectra even for sub-milligram samples. We show that when a 1.7 mm cryoprobe is available as little as 10 ?g of glycine in D2O is sufficient to obtain the HCNMBC spectrum in ca. 12 h. The preliminary results indicate that the pulse sequence has a great potential in the structure determination of nitrogen heterocycles especially in cases where synthesis produces regioisomers.

Cheatham, Steve; Gierth, Peter; Bermel, Wolfgang; Kup?e, ?riks

2014-10-01

380

Open system model of Pb isotope evolution of Galer & O'Nions (1985) Nature 316Galer & O'Nions (1985) Nature 316  

E-print Network

and continental crust Plum pudding modelPlum pudding model Model of a chemically unstratified mantle. SubductionOpen system model of Pb isotope evolution of the Earth Galer & O'Nions (1985) Nature 316Galer & O) = atomic Th/U ratio of Earth reservoir #12;Mantle model circa 1975 1982: Allègre Chemical Geodynamics

Siebel, Wolfgang

381

Use of U-Series Isotopic Disequilibrium to Investigate the Nature and Distribution of Actively Flowing Fractures  

NASA Astrophysics Data System (ADS)

Groundwater transport of radioisotopes from underground nuclear tests at the Nevada National Security Site (NNSS) is of concern to the U.S. Department of Energy. Extensive testing was conducted near or below the regional water table (saturated zone; SZ) at Pahute Mesa and within the unsaturated (or partially saturated) zone at Rainier Mesa. Groundwater flow in these rocks is believed to occur mainly through a connected network of fractures. To better understand flow in these fractured rocks, we analyzed U-series isotopes (238U-234U-230Th) from drill core samples. In rock isolated from flow over the last million years, isotopes in the 238U decay chain reach a state of radioactive secular equilibrium, where 234U/238U and 230Th/238U activity ratios (AR) = 1.0. More recent water-rock interaction results in mobilization of 234U relative to 238U, and U relative to Th in migrating waters. Rock surfaces that incorporate this U or are leached of 234U and U will show U-series disequilibrium. Isotope data can thus provide time-sensitive information on hydrologic conditions in host rocks without directly observing or measuring flowing water. To investigate NNSS fracture networks, core was selected from confining units (bedded and zeolitized felsic tuffs) and aquifers (felsic welded tuffs and lavas) in five boreholes on Pahute Mesa and two boreholes on Rainier Mesa. Samples include interiors of intact core as well as natural fracture surfaces and brecciated core. Intact core and brecciated samples were crushed and powdered. Fracture surfaces were sampled using dental burs to remove the outer 0.1 to 0.5 mm of fracture surfaces, which may have thin mineral coatings of zeolites, clays, and Mn oxides. Samples were totally digested, spiked with a 236U-229Th tracer, and analyzed by a solid-source TRITON mass spectrometer equipped with an energy filter and single ion counter. Results show that 8 of 9 intact core samples have 234U/238U AR within 5% of 1.0, suggesting little or no water-rock interaction over the last several hundred thousand years. In contrast, discrete fracture surfaces (N=37) have 234U/238U AR ranging from 2.09 to 0.34, although the median value is 1.04. About one third of the 28 SZ fracture surfaces have 234U/238U AR within 5% of 1.0. Remaining SZ fractures tend to have 234U/238U > 1.0,indicating that U incorporation from migrating groundwater (234U/238U AR ? 2-4) is an important process. Furthermore, samples with isotopic disequilibrium commonly plot along the equiline (equal 234U/238U and 230Th/238U AR) regardless of sample type or location. This pattern cannot be explained by deposition and closed-system isotope evolution of secondary minerals. Instead, it suggests a quasi-steady-state balance of processes including sorption or leaching of U associated with migrating solutions and in-situ production, decay, and ?-recoil of 230Th and 234U. These data will be used to help constrain numerical models of fracture-matrix interaction and spatial distribution of flowing versus non-flowing fractures.

Nichols, P. J.; Paces, J. B.; Neymark, L. A.; Rajaram, H.

2011-12-01

382

Protein Retention Assessment of Four Levels of Poultry By-Product Substitution of Fishmeal in Rainbow Trout (Oncorhynchus mykiss) Diets Using Stable Isotopes of Nitrogen (?15N) as Natural Tracers.  

PubMed

This is second part from an experiment where the nitrogen retention of poultry by-product meal (PBM) compared to fishmeal (FM) was evaluated using traditional indices. Here a quantitative method using stable isotope ratios of nitrogen (?15N values) as natural tracers of nitrogen incorporation into fish biomass is assessed. Juvenile rainbow trout (Oncorhynchus mykiss) were fed for 80 days on isotopically distinct diets in which 0, 33, 66 and 100% of FM as main protein source was replaced by PBM. The diets were isonitrogenous, isolipidic and similar in gross energy content. Fish in all treatments reached isotopic equilibrium by the end of the experiment. Two-source isotope mixing models that incorporated the isotopic composition of FM and PBM as well as that of formulated feeds, empirically derived trophic discrimination factors and the isotopic composition of fish that had reached isotopic equilibrium to the diets were used to obtain a quantitative estimate of the retention of each source of nitrogen. Fish fed the diets with 33 and 66% replacement of FM by PBM retained poultry by-product meal roughly in proportion to its level of inclusion in the diets, whereas no differences were detected in the protein efficiency ratio. Coupled with the similar biomass gain of fishes fed the different diets, our results support the inclusion of PBM as replacement for fishmeal in aquaculture feeds. A re-feeding experiment in which all fish were fed a diet of 100% FM for 28 days indicated isotopic turnover occurred very fast, providing further support for the potential of isotopic ratios as tracers of the retention of specific protein sources into fish tissues. Stable isotope analysis is a useful tool for studies that seek to obtain quantitative estimates of the retention of different protein sources. PMID:25226392

Badillo, Daniel; Herzka, Sharon Z; Viana, Maria Teresa

2014-01-01

383

Protein Retention Assessment of Four Levels of Poultry By-Product Substitution of Fishmeal in Rainbow Trout (Oncorhynchus mykiss) Diets Using Stable Isotopes of Nitrogen (?15N) as Natural Tracers  

PubMed Central

This is second part from an experiment where the nitrogen retention of poultry by-product meal (PBM) compared to fishmeal (FM) was evaluated using traditional indices. Here a quantitative method using stable isotope ratios of nitrogen (?15N values) as natural tracers of nitrogen incorporation into fish biomass is assessed. Juvenile rainbow trout (Oncorhynchus mykiss) were fed for 80 days on isotopically distinct diets in which 0, 33, 66 and 100% of FM as main protein source was replaced by PBM. The diets were isonitrogenous, isolipidic and similar in gross energy content. Fish in all treatments reached isotopic equilibrium by the end of the experiment. Two-source isotope mixing models that incorporated the isotopic composition of FM and PBM as well as that of formulated feeds, empirically derived trophic discrimination factors and the isotopic composition of fish that had reached isotopic equilibrium to the diets were used to obtain a quantitative estimate of the retention of each source of nitrogen. Fish fed the diets with 33 and 66% replacement of FM by PBM retained poultry by-product meal roughly in proportion to its level of inclusion in the diets, whereas no differences were detected in the protein efficiency ratio. Coupled with the similar biomass gain of fishes fed the different diets, our results support the inclusion of PBM as replacement for fishmeal in aquaculture feeds. A re-feeding experiment in which all fish were fed a diet of 100% FM for 28 days indicated isotopic turnover occurred very fast, providing further support for the potential of isotopic ratios as tracers of the retention of specific protein sources into fish tissues. Stable isotope analysis is a useful tool for studies that seek to obtain quantitative estimates of the retention of different protein sources. PMID:25226392

Badillo, Daniel; Herzka, Sharon Z.; Viana, Maria Teresa

2014-01-01

384

Total synthesis of junionone, a natural monoterpenoid from Juniperus communis L., and determination of the absolute configuration of the naturally occurring enantiomer by ROA spectroscopy.  

PubMed

Recently, we reported a novel access to 2,2-diethyl-3-[(E/Z)-prop-1-en-1-yl]cyclobutanone by an intramolecular nucleophilic substitution with allylic rearrangement (S(N)i') of (E)-6-chloro-3,3-diethylhept-4-en-2-one. The ring closure reaction was found to proceed with selective syn-displacement of the leaving group. This method was now applied to the total synthesis of junionone, an olfactorily interesting cyclobutane monoterpenoid isolated from Juniperus communis, L. S(N)i' Ring closure of the ketone enolate of (E)-3,3-dimethyl-5-[(2R,3R)-3-methyloxiran-2-yl]pent-4-en-2-one (R,R)-(E)-4' proceeded only after the epoxide moiety had been activated by Lewis acid and led to the junionone precursors (3R)- and (3S)-3-[(1E,3R)-3-hydroxybut-1-en-1-yl]-2,2-dimethylcyclobutanone (S/R,R)-(E)-3. The ratio of syn- and anti-conformers in the transitory molecular arrangement was found to depend on the nature of the Lewis acid. The absolute configuration of both the synthetic as well as the natural junionone, isolated from juniper berry oil, was determined by Raman Optical Activity (ROA) spectroscopy. Our experiments led to a novel synthetic route to both (+)- and (-)-junionone, the first determination of the absolute configuration of natural junionone, and to the development of a practical ROA procedure for measuring milligram quantities of volatile liquids. PMID:18205115

Lovchik, Martin A; Frter, Georg; Goeke, Andreas; Hug, Werner

2008-01-01