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Sample records for grey alder stands

  1. The impact of a pulsing groundwater table on greenhouse gas emissions in riparian grey alder stands.

    PubMed

    Mander, Ülo; Maddison, Martin; Soosaar, Kaido; Teemusk, Alar; Kanal, Arno; Uri, Veiko; Truu, Jaak

    2015-02-01

    Floods control greenhouse gas (GHG) emissions in floodplains; however, there is a lack of data on the impact of short-term events on emissions. We studied the short-term effect of changing groundwater (GW) depth on the emission of (GHG) carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in two riparian grey alder (Alnus incana) stands of different age in Kambja, southern Estonia, using the opaque static chamber (five replicates in each site) and gas chromatography methods. The average carbon and total nitrogen content in the soil of the old alder (OA) stand was significantly higher than in the young alder (YA) stand. In both stands, one part was chosen for water table manipulation (Manip) and another remained unchanged with a stable and deeper GW table. Groundwater table manipulation (flooding) significantly increases CH4 emission (average: YA-Dry 468, YA-Manip 8,374, OA-Dry 468, OA-Manip 4,187 μg C m(-2) h(-1)) and decreases both CO2 (average: OA-Dry 138, OA-Manip 80 mg C m(-2) h(-1)) and N2O emissions (average: OA-Dry 23.1, OA-Manip 11.8 μg N m(-2) h(-1)) in OA sites. There was no significant difference in CO2 and CH4 emissions between the OA and YA sites, whereas in OA sites with higher N concentration in the soil, the N2O emission was significantly higher than at the YA sites. The relative CO2 and CH4 emissions (the soil C stock-related share of gaseous losses) were higher in manipulated plots showing the highest values in the YA-Manip plot (0.03 and 0.0030 % C day(-1), respectively). The soil N stock-related N2O emission was very low achieving 0.000019 % N day(-1) in the OA-Dry plot. Methane emission shows a negative correlation with GW, whereas the 20 cm depth is a significant limit below which most of the produced CH4 is oxidized. In terms of CO2 and N2O, the deeper GW table significantly increases emission. In riparian zones of headwater streams, the short-term floods (e.g. those driven by extreme climate events) may significantly enhance

  2. Humus bacteria of Norway spruce stands: plant growth promoting properties and birch, red fescue and alder colonizing capacity.

    PubMed

    Elo; Maunuksela; Salkinoja-Salonen; Smolander; Haahtela

    2000-02-01

    We studied the potential of the humus layer of the Norway spruce stands to supply beneficial rhizobacteria to birch (Betula pendula), alder (Alnus incana) and fescue grass (Festuca rubra), representatives of pioneer vegetation after clear-cutting of the coniferous forest. Axenically grown seedlings of these species were inoculated with the acid spruce humus, pH 3.7-5.3. Actinorhizal propagules, capable of nodulating alder, were present in high density (10(3) g(-1)) in humus of long-term limed plots, whereas plots with nitrogen fertilization contained almost none (

  3. Root tensile strength of grey alder and mountain maple grown on a coarse grained eco-engineered slope in the Swiss Alps related to wood anatomical features

    NASA Astrophysics Data System (ADS)

    Kink, Dimitri; Bast, Alexander; Meyer, Christine; Meier, Wolfgang; Egli, Markus; Gärtner, Holger

    2014-05-01

    . In order to confirm this assumption and possibly find more important root properties which have an influence on soil stabilization, the root systems of seven trees (three grey alder, four mountain maple) were excavated and analyzed. The study site is a catchment, where shallow landslides are common. It is located in the Prättigau valley in the Eastern Swiss Alps and was eco-engineered in 1997. The substrate is coarse-grained morainic material, mean annual air temperature reaches 4.64°C, average precipitation is 1170 mm, and the altitude is about 1000 m a.s.l.. The root system of each tree was uncovered carefully by hand to keep the roots undamaged, before removal it was photographed in situ to document the root distribution. The root systems were then cut into single root pieces of about 20 cm length and the position of each sample was documented. The root samples were then hierarchically classified in several root classes. The tensile strength of more than 500 samples was determined. In addition, the values for age, diameter, and root moisture were ascertained. Since it was assumed, that the cellular structure of the roots has an influence on the tensile strength, two microscopic thin-sections were prepared from all successfully tested root samples. The microscopic analysis focused on anatomical parameters such as the size and number of vessels, their distribution as well as their conductivity. The results for the final correlation between the anatomical characteristics and the root's tensile strength are presented for both tree species.

  4. New Polybenzimidazole Architectures by Diels Alder Polymerization

    DTIC Science & Technology

    2012-02-14

    REPORT New Polybenzimidazole Architectures By Diels Alder Polymerization. Final Report 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: Due to their high...substituents to improve processability, are desirable. This project was a proof of principle study to determine if Diels - Alder polymerization of monomers...AND ADDRESSES U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS Polybenzimidazole, Diels Alder

  5. "Grey matters".

    PubMed

    Rose, Katie

    2014-01-01

    It's common in this world, for diagnoses to be confused. This grey, oblique world is the "World of Brain Tumors" from which these narratives are written, a world I entered when a tangerine-sized tumor was found on my temporal lobe. Each narrative illustrates this world in which everything is covered in a thick film rendering things once obvious, now unknown. Parents are asked to choose treatment plans for their children, plans that will inevitably alter their child's quality of life but in ways they cannot determine or even imagine. Parents are asked to play God. Most of the parents who share their stories in this collection, parents of PBT (pediatric brain tumor) patients have to walk the line of trying to not disrupt their relationships with their physicians, wanting the best for their child, and facing the decision to follow their gut or go with advised treatment plans.

  6. Headwater riparian invertebrate communities associated with red alder and conifer wood and leaf litter in southeastern Alaska

    USGS Publications Warehouse

    LeSage, C.M.; Merritt, R.W.; Wipfli, M.S.

    2005-01-01

    We examined how management of young upland forests in southeastern Alaska affect riparian invertebrate taxa richness, density, and biomass, in turn, potentially influencing food abundance for fish and wildlife. Southeastern Alaska forests are dominated by coniferous trees including Sitka spruce (Picea sitchensis (Bong.) Carr.), western hemlock (Tsuga heterophylla (Raf.) Sarg.), with mixed stands of red cedar (Thuja plicata Donn.). Red alder (Alnus rubra Bong.) is hypothesized to influence the productivity of young-growth conifer forests and through forest management may provide increased riparian invertebrate abundance. To compare and contrast invertebrate densities between coniferous and alder riparian habitats, leaf litter and wood debris (early and late decay classes) samples were collected along eleven headwater streams on Prince of Wales Island, Alaska, during the summers of 2000 and 2001. Members of Acarina and Collembola were the most abundant taxa collected in leaf litter with alder litter having significantly higher mean taxa richness than conifer litter. Members of Acarina were the most abundant group collected on wood debris and alder wood had significantly higher mean taxa richness and biomass than conifer wood. Alder wood debris in more advanced decay stages had the highest mean taxa richness and biomass, compared to other wood types, while conifer late decay wood debris had the highest densities of invertebrates. The inclusion of alder in young-growth conifer forests can benefit forest ecosystems by enhancing taxa richness and biomass of riparian forest invertebrates. ?? 2005 by the Northwest Scientific Association. All rights reserved.

  7. 35. GREY IRON TUMBLERS, IN THE GREY IRON FOUNDRY ROTATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. GREY IRON TUMBLERS, IN THE GREY IRON FOUNDRY ROTATE CASTINGS WITH SHOT TO REMOVE AND SURFACE OXIDES AND REMAINING EXCESS METALS. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  8. Use of wetlands for production of woody plants for fuels and petrochemical substitutes. [Alders, willows, poplars

    SciTech Connect

    Farnham, R.S.; Read, P.

    1981-03-01

    Work performed on this project in the past year has included the evaluations of natural stands productivity for wetland biomass species; propagation studies with alder, willow and poplar species; nursery establishment for production of cultivars and evaluation of wetland soils suitable for production of woody biomass species. Also a biomass research facility has been established in N. Minnesota suitable for long-term research and demonstration. Propagation research has included both micro and macro propagation techniques with native willows, selected willow clones from Sweden, alder seed selection from Finland and hybrid poplar clones from US Forest Service, Rhinelander, Wisconsin. Approximately 100,000 rooted plants will be available for field research by June 1, 1981.

  9. Factors affecting distribution of wood, detritus, and sediment in headwater streams draining managed young-growth red alder - Conifer forests in southeast Alaska

    USGS Publications Warehouse

    Gomi, T.; Johnson, A.C.; Deal, R.L.; Hennon, P.E.; Orlikowska, E.H.; Wipfli, M.S.

    2006-01-01

    Factors (riparian stand condition, management regimes, and channel properties) affecting distributions of wood, detritus (leaves and branches), and sediment were examined in headwater streams draining young-growth red alder (Alnus rubra Bong.) - conifer riparian forests (40 years old) remained in channels and provided sites for sediment and organic matter storage. Despite various alder-conifer mixtures and past harvesting effects, the abundance of large wood, fine wood, and detritus accumulations significantly decreased with increasing channel bank-full width (0.5-3.5 m) along relatively short channel distances (up to 700 m). Changes in wood, detritus, and sediment accumulations together with changes in riparian stand characteristics create spatial and temporal variability of in-channel conditions in headwater systems. A component of alder within young-growth riparian forests may benefit both wood production and biological recovery in disturbed headwater stream channels. ?? 2006 NRC.

  10. Uncertainty representation of grey numbers and grey sets.

    PubMed

    Yang, Yingjie; Liu, Sifeng; John, Robert

    2014-09-01

    In the literature, there is a presumption that a grey set and an interval-valued fuzzy set are equivalent. This presumption ignores the existence of discrete components in a grey number. In this paper, new measurements of uncertainties of grey numbers and grey sets, consisting of both absolute and relative uncertainties, are defined to give a comprehensive representation of uncertainties in a grey number and a grey set. Some simple examples are provided to illustrate that the proposed uncertainty measurement can give an effective representation of both absolute and relative uncertainties in a grey number and a grey set. The relationships between grey sets and interval-valued fuzzy sets are also analyzed from the point of view of the proposed uncertainty representation. The analysis demonstrates that grey sets and interval-valued fuzzy sets provide different but overlapping models for uncertainty representation in sets.

  11. Can Puva Darken Grey Hair.

    PubMed

    Pasricha, J S

    1987-01-01

    Grey hairs obtained from patients having premature grey hairs were exposed to UVA or UVB for 30 mmutes daily for 17 days and another group of grey hairs were first daily painted with 1% aqueous solution of psoralen and then exposed to UVA for 30 minutes for 17 days. Under neither of these conditions, the greys hairs showed any darkening.

  12. Synthesis of Antitumor Lycorines by Intramolecular Diels-Alder Reaction.

    PubMed

    Pérez, Dolores; Burés, Gema; Guitián, Enrique; Castedo, Luis

    1996-03-08

    Pharmacologically interesting lycorines were obtained by a short, efficient method based on an intramolecular Diels-Alder reaction between an alpha-pyrone and an alkyne, followed by loss of CO(2) in a retro Diels-Alder reaction. The cyclization precursors (pyrones 9) were obtained in good yields in two or three steps from the corresponding homophthalic acid or anhydride.

  13. Covalently crosslinked diels-alder polymer networks.

    SciTech Connect

    Bowman, Christopher; Adzima, Brian J.; Anderson, Benjamin John

    2011-09-01

    This project examines the utility of cycloaddition reactions for the synthesis of polymer networks. Cycloaddition reactions are desirable because they produce no unwanted side reactions or small molecules, allowing for the formation of high molecular weight species and glassy crosslinked networks. Both the Diels-Alder reaction and the copper-catalyzed azide-alkyne cycloaddition (CuAAC) were studied. Accomplishments include externally triggered healing of a thermoreversible covalent network via self-limited hysteresis heating, the creation of Diels-Alder based photoresists, and the successful photochemical catalysis of CuAAC as an alternative to the use of ascorbic acid for the generation of Cu(I) in click reactions. An analysis of the results reveals that these new methods offer the promise of efficiently creating robust, high molecular weight species and delicate three dimensional structures that incorporate chemical functionality in the patterned material. This work was performed under a Strategic Partnerships LDRD during FY10 and FY11 as part of a Sandia National Laboratories/University of Colorado-Boulder Excellence in Science and Engineering Fellowship awarded to Brian J. Adzima, a graduate student at UC-Boulder. Benjamin J. Anderson (Org. 1833) was the Sandia National Laboratories point-of-contact for this fellowship.

  14. Can an Alder Disease Influence the Controls of Ecosystem Water Flux?

    NASA Astrophysics Data System (ADS)

    Rohrs-Richey, J. K.; Mulder, C. P.; Ruess, R. W.; Winton, L. M.; Stanosz, G. R.

    2007-12-01

    In Alaska, nitrogen-fixing shrubs (Alnus spp.) comprise a large component of the vegetation and are important for water and energy flux in the Alaskan tundra, the Interior boreal forest, and south-central Alaska. Recently there has been high incidence and severity of a canker disease on Alnus which alters small scale controls (e.g., leaves, branches) of water and carbon flux and may have ecosystem scale effects in severely diseased areas. The fungal pathogen, Valsa melanodiscus (anamorph =Cytospora umbrina), kills active xylem and phloem, causes long, girdling cankers on stems, and is frequently associated with stem mortality in the thin leaf alder (Alnus tenuifolia) and green alder (Alnus crispa). We are just beginning to understand how this canker disease affects the physiology of its host and the implications for water loss and carbon fixation. An inoculation experiment at the University of Alaska is currently being conducted on well-watered and water-limited green alders to: 1) monitor the response of the water transport system to infection and canker development; 2) assess the ability of colonized alders to adjust water use efficiency; and 3) measure the effect of canker development on photosynthesis. Only 4 weeks after inoculation, stems (3-5 mm diam.) with incipient cankers had an overall reduction in total daily water loss and up to 50 percent decrease in daily peak water loss. Stems with incipient cankers were also unable to attain the maximum photosynthetic rate of healthy stems, and had lower light saturation points and quantum efficiencies. Further quantification of these relationships is underway. This study, in combination with recent field measurements of sapflow, will allow us to estimate the impact of varying degrees of disease severity on stand-level water flux. Alders are a keystone species and are currently responding to climate change by expanding into the Alaska tundra, increasing abundance in northern Alaska, and migrating into river

  15. Grey swan tropical cyclones

    NASA Astrophysics Data System (ADS)

    Lin, Ning; Emanuel, Kerry

    2016-01-01

    We define `grey swan’ tropical cyclones as high-impact storms that would not be predicted based on history but may be foreseeable using physical knowledge together with historical data. Here we apply a climatological-hydrodynamic method to estimate grey swan tropical cyclone storm surge threat for three highly vulnerable coastal regions. We identify a potentially large risk in the Persian Gulf, where tropical cyclones have never been recorded, and larger-than-expected threats in Cairns, Australia, and Tampa, Florida. Grey swan tropical cyclones striking Tampa, Cairns and Dubai can generate storm surges of about 6 m, 5.7 m and 4 m, respectively, with estimated annual exceedance probabilities of about 1/10,000. With climate change, these probabilities can increase significantly over the twenty-first century (to 1/3,100-1/1,100 in the middle and 1/2,500-1/700 towards the end of the century for Tampa). Worse grey swan tropical cyclones, inducing surges exceeding 11 m in Tampa and 7 m in Dubai, are also revealed with non-negligible probabilities, especially towards the end of the century.

  16. Grey water biodegradability.

    PubMed

    Ghunmi, Lina Abu; Zeeman, Grietje; Fayyad, Manar; van Lier, Jules B

    2011-02-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different conditions in the biodegradation test. The maximum aerobic and anaerobic biodegradability and conversion rate for the different COD fractions is determined. The results show that, on average, dormitory grey water COD fractions are 28% suspended, 32% colloidal and 40% dissolved. The studied factors incubation time, inoculum addition and temperature are influencing the determined biodegradability. The maximum biodegradability and biodegradation rate differ between different COD fractions, viz. COD(ss), COD(col) and COD(diss). The dissolved COD fraction is characterised by the lowest degradation rate, both for anaerobic and aerobic conditions. The maximum biodegradability for aerobic and anaerobic conditions is 86 and 70% respectively, whereas the first order conversion rate constant, k₂₀, is 0.119 and 0.005 day⁻¹, respectively. The anaerobic and aerobic conversion rates in relation to temperature can be described by the Arrhenius relation, with temperature coefficients of 1.069 and 1.099, respectively.

  17. Effects of Alder Mine on the Water, Sediments, and Benthic Macroinvertebrates of Alder Creek, 1998 Annual Report.

    SciTech Connect

    Peplow, Dan

    1999-05-28

    The Alder Mine, an abandoned gold, silver, copper, and zinc mine in Okanogan County, Washington, produces heavy metal-laden effluent that affects the quality of water in a tributary of the Methow River. The annual mass loading of heavy metals from two audits at the Alder Mine was estimated to exceed 11,000 kg per year. In this study, water samples from stations along Alder Creek were assayed for heavy metals by ICP-AES and were found to exceed Washington State's acute freshwater criteria for cadmium (Cd), copper (Cu), selenium (Se), and zinc (Zn).

  18. The pentadehydro-Diels–Alder reaction

    PubMed Central

    Wang, Teng; Naredla, Rajasekhar Reddy; Thompson, Severin K.; Hoye, Thomas R

    2016-01-01

    In the classic Diels–Alder (DA) [4+2] cycloaddition reaction1, the overall degree of unsaturation of the 4π (diene) and 2π (dienophile) pairs of reactants dictates the oxidation state of the newly formed six-membered carbocycle. For example, in the classic DA reaction, butadiene and ethylene combine to produce cyclohexene. More recent developments include variants in which the hydrogen atom count in the reactant pair and in the resulting product is reduced by2, for example, four in the tetradehydro-DA (TDDA) and by six in the hexadehydro-DA (HDDA3,4,5,6,7) reactions. Any oxidation state higher than tetradehydro leads to the production of a reactive intermediate that is more highly oxidized than benzene. This significantly increases the power of the overall process because trapping of the benzyne intermediate8,9 can be used to increase the structural complexity of the final product in a controllable and versatile manner. In this manuscript, we report an unprecedented net 4π+2π cycloaddition reaction that generates a different, highly reactive intermediate known as an α,3-dehydrotoluene. This species is at the same oxidation state as a benzyne. Like benzynes, α,3-dehydrotoluenes can be captured by various trapping agents to produce structurally diverse products that are complementary to those arising from the HDDA process. We call this new cycloisomerization reaction a pentadehydro-Diels–Alder (PDDA) reaction—a nomenclature chosen for chemical taxonomic rather than mechanistic reasons. In addition to alkynes, nitriles (RC≡N), although non-participants in aza-HDDA reactions, readily function as the 2π-component in PDDA cyclizations to produce, via trapping of the α,3-(5-aza)dehydrotoluene intermediates, pyridine-containing products. PMID:27088605

  19. A Diels-Alder Route to Angularly Functionalized Bicyclic Structures

    PubMed Central

    Kim, Woo Han; Lee, Jun Hee; Aussedat, Baptiste; Danishefsky, Samuel J.

    2010-01-01

    A Diels-Alder based route to trans-fused angularly functionalized bicyclic structures has been developed. This transformation features the use of a tetrasubstituted dienophile in the cycloaddition step. PMID:20717474

  20. The hetero-Diels-Alder approach to spiroketals.

    PubMed

    Rizzacasa, Mark A; Pollex, Annett

    2009-03-21

    The hetero-Diels-Alder reaction can provide spiroketal systems with excellent stereoselectivity. This perspective article will briefly outline the scope and limitations of this approach for the production of naturally occurring spiroketals and derivatives.

  1. The hexadehydro-Diels–Alder reaction

    PubMed Central

    Hoye, Thomas R.; Baire, Beeraiah; Niu, Dawen; Willoughby, Patrick H.; Woods, Brian P.

    2012-01-01

    Summary o-Benzynes (arynes) are among the most versatile of all reactive (short-lived) intermediates in organic chemistry. These species can be trapped to give products that are valuable from the perspective of both fine (pharmaceuticals) and commodity (agrochemicals, dyes, polymers, etc.) chemicals. Here we show a fundamentally new strategy that unites a de novo generation of benzynes, through the title hexadehydro-Diels–Alder (HDDA) reaction, with their in situ elaboration into structurally complex benzenoid products. In the HDDA reaction a 1,3-diyne is engaged in a [4+2] cycloisomerization with a third (pendant) alkyne–the diynophile–to produce the highly reactive benzyne intermediate. The metal- and reagent-free reaction conditions for this simple, thermal transformation are notable. The subsequent and highly efficient trapping reactions increase the power of the overall process. Finally, we provide examples of how this de novo benzyne generation approach allows new modes of intrinsic reactivity to be revealed. PMID:23060191

  2. New nomenclature combinations in the green alder species complex (Betulaceae)

    PubMed Central

    Chery, Joyce

    2015-01-01

    Abstract The name Alnus viridis (Chaix) DC., based on Betula viridis Chaix (1785), has traditionally been attributed to green alders although it is based on a later basionym. Alnus alnobetula (Ehrh.) K. Koch based on Betula alnobetula Ehrh. (1783) is the correct name for green alders. In light of the increasing use and recognition of the name Alnus alnobetula (Ehrh.) K. Koch in the literature. I herein propose new nomenclatural combinations to account for the Japanese and Chinese subspecies respectively: Alnus alnobetula subsp. maximowiczii (Callier ex C.K. Schneid.) J. Chery and Alnus alnobetula subsp. mandschurica (Callier ex C.K. Schneid.) J. Chery. Recent phylogenetic analyses place these two taxa in the green alder species complex, suggesting that they should be treated as infraspecific taxa under the polymorphic Alnus alnobetula. PMID:26491381

  3. Permuting Diels-Alder and Robinson Annulation Stereopatterns.

    PubMed

    Peng, Feng; Dai, Mingji; Angeles, Angie R; Danishefsky, Samuel J

    2012-01-01

    Controlled isomerization of the double bond of certain Diels-Alder reactions provides substrates that, upon oxidation, give rise to products whose gross structure corresponds to that of a Robinson annulation. In these cases, the stereochemistry of the Robinson annulation product reflects the fact that the initial combination occurred in a Diels-Alder mode. Using these principles, we have synthesized carissone and cosmosoic acid. In the latter case, our total synthesis raised serious questions as to the accuracy of the assigned structure of the natural product.

  4. High stereoselectivity on low temperature Diels-Alder reactions

    PubMed Central

    da Silva Filho, Luiz Carlos; Lacerda Júnior, Valdemar; Constantino, Mauricio Gomes; da Silva, Gil Valdo José; Invernize, Paulo Roberto

    2005-01-01

    We have found that some of the usually poor dienophiles (2-cycloenones) can undergo Diels-Alder reaction at -78°C with unusually high stereoselectivity in the presence of niobium pentachloride as a Lewis acid catalyst. A remarkable difference in reaction rates for unsubstituted and α- or β-methyl substituted 2-cycloenones was also observed. PMID:16542029

  5. 61. Photocopy of Engine Room Floor Plan, White Alder. The ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    61. Photocopy of Engine Room Floor Plan, White Alder. The Niagara Shipbuilding Corp. Engineering Department, Buffalo, New York. Coast Guard Headquarters Drawing No. 540-WAGL-1604-10, dated February 1943; revised January 1963. Original drawing property of the U.S. Coast Guard. - U.S. Coast Guard Cutter WHITE HEATH, USGS Integrated Support Command Boston, 427 Commercial Street, Boston, Suffolk County, MA

  6. N2-fixing red alder indirectly accelerates ecosystem nitrogen cycling

    USGS Publications Warehouse

    Perakis, Steven S.; Matkins, Joselin J.; Hibbs, David E.

    2012-01-01

    Symbiotic N2-fixing tree species can accelerate ecosystem N dynamics through decomposition via direct pathways by producing readily decomposed leaf litter and increasing N supply to decomposers, as well as via indirect pathways by increasing tissue and detrital N in non-fixing vegetation. To evaluate the relative importance of these pathways, we compared three-year decomposition and N dynamics of N2-fixing red alder leaf litter (2.34 %N) to both low-N (0.68 %N) and high-N (1.21 %N) litter of non-fixing Douglas-fir, and decomposed each litter source in four forests dominated by either red alder or Douglas-fir. We also used experimental N fertilization of decomposition plots to assess elevated N availability as a potential mechanism of N2-fixer effects on litter mass loss and N dynamics. Direct effects of N2-fixing red alder on decomposition occurred primarily as faster N release from red alder than Douglas-fir litter, but direct increases in N supply to decomposers via fertilization did not stimulate decomposition of any litter. Fixed N indirectly influenced detrital dynamics by increasing Douglas-fir tissue and litter N concentrations, which accelerated litter N release without accelerating mass loss. By increasing soil N, tissue N, and the rate of N release from litter of non-fixers, we conclude that N2-fixing vegetation can indirectly foster plant-soil feedbacks that contribute to the persistence of elevated N availability in terrestrial ecosystems.

  7. Take a Stand for Standing

    ERIC Educational Resources Information Center

    Labandz, Stephenie

    2010-01-01

    As a school-based physical therapist, the author sees children with a wide variety of diagnoses affecting their mobility and motor function. Supported standing is an important part of the routines of those who are unable to stand independently due to issues affecting the neuromuscular system. Being eye-to-eye with their peers and interacting with…

  8. Application of the aza-Diels-Alder reaction in the synthesis of natural products.

    PubMed

    Cao, Min-Hui; Green, Nicholas J; Xu, Sheng-Zhen

    2017-03-22

    The Diels-Alder reaction that involves a nitrogen atom in the diene or dienophile is termed the aza-Diels-Alder reaction. As well as the powerful all-carbon Diels-Alder reaction, the aza-Diels-Alder reaction has also played an important role in the total synthesis of natural products. Herein, we review various natural products using an aza-Diels-Alder reaction as a key step to their total synthesis, and divide the syntheses into inter- and intra-molecular aza-Diels-Alder reactions and a retro-aza-Diels-Alder reaction. Inter- and intra-molecular aza-Diels-Alder reactions involve an imine as an electron deficient dienophile and an imine as an electron deficient azadiene. The significance of the aza-Diels-Alder reaction for the construction of a six-membered ring containing nitrogen is tremendous, but the development of asymmetric, in particular catalytic enantioselective intramolecular aza-Diels-Alder reaction in the total synthesis of natural products remains highly challenging, and will no doubt see enormous advances in the future.

  9. Whole-brain grey matter density predicts balance stability irrespective of age and protects older adults from falling.

    PubMed

    Boisgontier, Matthieu P; Cheval, Boris; van Ruitenbeek, Peter; Levin, Oron; Renaud, Olivier; Chanal, Julien; Swinnen, Stephan P

    2016-03-01

    Functional and structural imaging studies have demonstrated the involvement of the brain in balance control. Nevertheless, how decisive grey matter density and white matter microstructural organisation are in predicting balance stability, and especially when linked to the effects of ageing, remains unclear. Standing balance was tested on a platform moving at different frequencies and amplitudes in 30 young and 30 older adults, with eyes open and with eyes closed. Centre of pressure variance was used as an indicator of balance instability. The mean density of grey matter and mean white matter microstructural organisation were measured using voxel-based morphometry and diffusion tensor imaging, respectively. Mixed-effects models were built to analyse the extent to which age, grey matter density, and white matter microstructural organisation predicted balance instability. Results showed that both grey matter density and age independently predicted balance instability. These predictions were reinforced when the level of difficulty of the conditions increased. Furthermore, grey matter predicted balance instability beyond age and at least as consistently as age across conditions. In other words, for balance stability, the level of whole-brain grey matter density is at least as decisive as being young or old. Finally, brain grey matter appeared to be protective against falls in older adults as age increased the probability of losing balance in older adults with low, but not moderate or high grey matter density. No such results were observed for white matter microstructural organisation, thereby reinforcing the specificity of our grey matter findings.

  10. Grey Literature and the Internet

    ERIC Educational Resources Information Center

    Hartman, Karen A.

    2006-01-01

    Accreditation standards for professional schools offering social work degrees mandate curriculum content that provides students with skills to analyze, formulate, and influence social policies. An important source of analytical thinking about social policy is the "grey" literature issued by public policy organizations, think tanks,…

  11. Tree Age Effects on Fine Root Biomass and Morphology over Chronosequences of Fagus sylvatica, Quercus robur and Alnus glutinosa Stands

    PubMed Central

    Jagodzinski, Andrzej M.; Ziółkowski, Jędrzej; Warnkowska, Aleksandra; Prais, Hubert

    2016-01-01

    There are few data on fine root biomass and morphology change in relation to stand age. Based on chronosequences for beech (9–140 years old), oak (11–140 years) and alder (4–76 years old) we aimed to examine how stand age affects fine root biomass and morphology. Soil cores from depths of 0–15 cm and 16–30 cm were used for the study. In contrast to previously published studies that suggested that maximum fine root biomass is reached at the canopy closure stage of stand development, we found almost linear increases of fine root biomass over stand age within the chronosequences. We did not observe any fine root biomass peak in the canopy closure stage. However, we found statistically significant increases of mean fine root biomass for the average individual tree in each chronosequence. Mean fine root biomass (0–30 cm) differed significantly among tree species chronosequences studied and was 4.32 Mg ha-1, 3.71 Mg ha-1 and 1.53 Mg ha-1, for beech, oak and alder stands, respectively. The highest fine root length, surface area, volume and number of fine root tips (0–30 cm soil depth), expressed on a stand area basis, occurred in beech stands, with medium values for oak stands and the lowest for alder stands. In the alder chronosequence all these values increased with stand age, in the beech chronosequence they decreased and in the oak chronosequence they increased until ca. 50 year old stands and then reached steady-state. Our study has proved statistically significant negative relationships between stand age and specific root length (SRL) in 0–30 cm soil depth for beech and oak chronosequences. Mean SRLs for each chronosequence were not significantly different among species for either soil depth studied. The results of this study indicate high fine root plasticity. Although only limited datasets are currently available, these data have provided valuable insight into fine root biomass and morphology of beech, oak and alder stands. PMID:26859755

  12. Tree Age Effects on Fine Root Biomass and Morphology over Chronosequences of Fagus sylvatica, Quercus robur and Alnus glutinosa Stands.

    PubMed

    Jagodzinski, Andrzej M; Ziółkowski, Jędrzej; Warnkowska, Aleksandra; Prais, Hubert

    2016-01-01

    There are few data on fine root biomass and morphology change in relation to stand age. Based on chronosequences for beech (9-140 years old), oak (11-140 years) and alder (4-76 years old) we aimed to examine how stand age affects fine root biomass and morphology. Soil cores from depths of 0-15 cm and 16-30 cm were used for the study. In contrast to previously published studies that suggested that maximum fine root biomass is reached at the canopy closure stage of stand development, we found almost linear increases of fine root biomass over stand age within the chronosequences. We did not observe any fine root biomass peak in the canopy closure stage. However, we found statistically significant increases of mean fine root biomass for the average individual tree in each chronosequence. Mean fine root biomass (0-30 cm) differed significantly among tree species chronosequences studied and was 4.32 Mg ha(-1), 3.71 Mg ha(-1) and 1.53 Mg ha(-1), for beech, oak and alder stands, respectively. The highest fine root length, surface area, volume and number of fine root tips (0-30 cm soil depth), expressed on a stand area basis, occurred in beech stands, with medium values for oak stands and the lowest for alder stands. In the alder chronosequence all these values increased with stand age, in the beech chronosequence they decreased and in the oak chronosequence they increased until ca. 50 year old stands and then reached steady-state. Our study has proved statistically significant negative relationships between stand age and specific root length (SRL) in 0-30 cm soil depth for beech and oak chronosequences. Mean SRLs for each chronosequence were not significantly different among species for either soil depth studied. The results of this study indicate high fine root plasticity. Although only limited datasets are currently available, these data have provided valuable insight into fine root biomass and morphology of beech, oak and alder stands.

  13. Is it true that polymerization of vegetable oil occurs through Diels-Alder reaction?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diels-Alder reaction mechanism is known to be one of the major reaction mechanisms to produce dimers and polymers during heating process of vegetable oil. However, our NMR study showed no evidence for Diels-Alder products. Soybean oil oxidized at 180 °C for 24 hrs with 1.45 surface area-to-volume ...

  14. Why a Proximity-Induced Diels–Alder Reaction is So Fast

    PubMed Central

    Krenske, Elizabeth H.; Perry, Emma W.; Jerome, Steven V.; Maimone, Thomas J.; Baran, Phil S.; Houk, K. N.

    2012-01-01

    Unlike normal Diels–Alder reactions of acyclic alkadienes with alkenes, the vinylbicyclo[2.2.2]octene employed in the Baran total synthesis of vinigrol undergoes quantitative Diels–Alder reaction with a tethered alkene at room temperature. Density functional theory calculations reveal that this unprecedented reactivity originates from a combination of preorganization, diene strain, and tether stabilization. PMID:22630569

  15. Alder (alnus crispa) effects on soils in ecosystems of the Agashashok river valley, northwest Alaska

    USGS Publications Warehouse

    Rhoades, C.; Oskarsson, H.; Binkley, D.; Stottlemyer, B.

    2001-01-01

    At the northern limit of the boreal forest biome, alder (Alnus crispa [Ait.] Pursh) shrubs occur in a variety of ecosystems. We assessed the effects of individual alder shrubs on soil properties and understory plant tissue nitrogen in floodplain terraces, valley slopes and tussock tundra ridges. The three ecosystems differed with respect to soil properties and abiotic conditions and supported distinct plant communities. Alder increased resin-exchangeable soil N and NO3 production significantly in each ecosystem. The greatest difference between alder canopy and surrounding soil NO3 measured both under field and laboratory conditions occured in floodplain sites. The shrub effect on soil pH and soil organic matter was greatest on tundra ridges. Alder shrubs also influenced the nitrogen nutrition of plants growing beneath their canopies. Plants growing below alder canopies had higher foliar nitrogen concentration and natural abundance 15N composition and lower carbon to nitrogen ratio than open-grown plants. Similar to soil N availability, understory plant leaf chemistry responded more to alder on floodplains than on slope or tundra ecosystems. This pattern suggests that understory plants rely more heavily on alder-fixed-N in this resource-poor ecosystem.

  16. A facile avenue to conductive polymer brushes via cyclopentadiene-maleimide Diels-Alder ligation.

    PubMed

    Yameen, Basit; Rodriguez-Emmenegger, Cesar; Preuss, Corinna M; Pop-Georgievski, Ognen; Verveniotis, Elisseos; Trouillet, Vanessa; Rezek, Bohuslav; Barner-Kowollik, Christopher

    2013-10-07

    Cyclopentadienyl end-capped poly(3-hexylthiophene) was employed to fabricate conductive surface tethered polymer brushes via a facile route based on cyclopentadiene-maleimide Diels-Alder ligation. The efficient nature of the Diels-Alder ligation was further combined with a biomimetic polydopamine-assisted functionalization of surfaces, making it an access route of choice for P3HT surface immobilization.

  17. Acquired ciliary circumscribed grey hair (ACCG).

    PubMed

    Romero, A G; Calatayud, J C

    2001-12-01

    Grey-haired areas usually occur due to aging or inheritance. A case is described of abrupt occurrence of a focal circumscribed grey-hair in the eyebrow region (a single hair) in a 27-year-old woman. The phenomenon was named acquired ciliary circumscribed grey-hair (ACCG). Qualitative and semiquantitative findings were obtained by microanalytical studies. In addition to morphological differences from control hair, the ACCG hair showed a high percentage of sulfur (99.8%) and absence of oligoelements.

  18. Heavy metal stress in alders: Tolerance and vulnerability of the actinorhizal symbiosis.

    PubMed

    Bélanger, Pier-Anne; Bellenger, Jean-Philippe; Roy, Sébastien

    2015-11-01

    Alders have already demonstrated their potential for the revegetation of both mining and industrial sites. These actinorhizal trees and shrubs and the actinobacteria Frankia associate in a nitrogen-fixing symbiosis which could however be negatively affected by the presence of heavy metals, and accumulate them. In our hydroponic assay with black alders, quantification of the roots and shoots metal concentrations showed that, in the absence of stress, symbiosis increases Mo and Ni root content and simultaneously decreases Mo shoot content. Interestingly, the Mo shoot content also decreases in the presence of Ni, Cu, Pb, Zn and Cd for symbiotic alders. In symbiotic alders, Pb shoot translocation was promoted in presence of Pb. On the other hand, Cd exclusion in symbiotic root tissues was observed with Pb and Cd. In the presence of symbiosis, only Cd and Pb showed translocation into aerial tissues when present in the nutrient solution. Moreover, the translocation of Ni to shoot was prevented by symbiosis in the presence of Cd, Ni and Pb. The hydroponic experiment demonstrated that alders benefit from the symbiosis, producing more biomass (total, root and shoot) than non nodulated alders in control condition, and in the presence of metals (Cu, Ni, Zn, Pb and Cd). Heavy metals did not reduce the nodule numbers (SNN), but the presence of Zn or Cd did reduce nodule allocation. Our study suggests that the Frankia-alder symbiosis is a promising (and a compatible) plant-microorganism association for the revegetation of contaminated sites, with minimal risk of metal dispersion.

  19. Locating grey literature on communication disorders.

    PubMed

    Shpilko, Inna

    2005-01-01

    This article provides an overview of selected Web-based resources containing grey literature in the area of communication disorders. It is geared to practitioners, researchers, students, and consumers seeking reliable, freely available scientific information. Grey (or gray) literature has been defined as "that which is produced on all levels of government, academics, business, and industry in print and electronic formats, but which is not controlled by commercial publishers."1 This paper reviews various general reference sources potentially containing grey literature on communication disorders. This review includes identification of the methods specialists in this field use to obtain this valuable, yet often overlooked, literature. Access points and search tools for identifying grey literature on communication disorders are recommended. Commercial databases containing grey literature are not included. Conclusions presented in this article are considered complementary to traditionally published information resources on communication disorders, such as scholarly journals, online databases, etc.

  20. [Alder forests of Numidia (N.E. Algeria): floristic biodiversity, vulnerability and conservation].

    PubMed

    Belouahem-Abed, Djamila; Belouahem, Foudil; Benslama, Mohamed; de Bélair, Gérard; Muller, Serge D

    2011-01-01

    The phytoecological study of the alder forests of north-east Algeria shows that these habitats with boreal affinities harbour very high species richness (> 400 species) and complex structures, which suggest their ancient origin. They correspond phytosociologically to two syntaxa, the Campanulo alatae-Alnenion glutinosae (riparian alder forests) and the Rusco hypophylli-Alnetum glutinosae (peat-forming alder carrs), respectively. Their degraded state and their regressive dynamics, observed during the 14 years of the study, reveal their precarious situation and their rapid ongoing decline under the influence of human-induced uncontroled disturbances (cutting, burning, draining, dumping…). With regard to their ecological, historical and patrimonial importance, the alder forests of Algerian Numidia should be urgently protected, with the aim of assuring the perennity of their exceptional floristic corteges.

  1. Envisioning an enzymatic Diels-Alder reaction by in situ acid-base catalyzed diene generation.

    PubMed

    Linder, Mats; Johansson, Adam Johannes; Manta, Bianca; Olsson, Philip; Brinck, Tore

    2012-06-07

    We present and evaluate a new and potentially efficient route for enzyme-mediated Diels-Alder reactions, utilizing general acid-base catalysis. The viability of employing the active site of ketosteroid isomerase is demonstrated.

  2. Rheological and chemical analysis of reverse gelation in a covalently crosslinked Diels-Alder polymer network

    PubMed Central

    Adzima, Brian J.; Aguirre, H. Alan; Kloxin, Christopher J.; Scott, Timothy F.; Bowman, Christopher N.

    2009-01-01

    A network polymer, incorporating dynamic and reversible crosslinks, was synthesized using the Diels-Alder reaction. Fourier transform infrared (FTIR) spectroscopy was used to characterize the reaction rate and thermodynamic equilibrium over a broad temperature range. Equilibrium conversion of the furan and maleimide varied from 74% at 85°C to 24% at 155°C, demonstrating significant depolymerization via the retro-Diels-Alder reaction. The gel point temperature, as determined by rheometry using the Winter-Chambon criterion, was 92°C, corresponding to a gel-point conversion of 71%, consistent with the Flory-Stockmayer equation. The scaling exponents for the complex moduli, viscosity, and plateau modulus, in the vicinity of the gel-point, were determined and compared with experimental and theoretical literature values. Further, the material exhibited a low frequency relaxation owing to dynamic rearrangement of crosslinks by the Diels-Alder and retro-Diels-Alder reactions. PMID:20711364

  3. Mannich-Michael versus formal aza-Diels-Alder approaches to piperidine derivatives.

    PubMed

    Girling, P Ricardo; Kiyoi, Takao; Whiting, Andrew

    2011-05-07

    A review into the aza-Diels-Alder reaction, mainly concentrating on literature examples that form piperidin-4-ones from the reaction of imines and electron rich dienes or enones, either through a Lewis acidic/Brønsted acid approach or through the use of an organocatalyst. This review questions whether the mechanism of the aza-Diels-Alder reaction is step wise as opposed to concerted when using oxygenated dienes.

  4. Looking beyond the endo Rule in a Diels-Alder Discovery Lab

    NASA Astrophysics Data System (ADS)

    Jarret, Ronald M.; New, Jamie; Hurley, Rebecca; Gillooly, Laura

    2001-09-01

    The commonly described reaction of maleic anhydride and cyclopentadiene generates a Diels-Alder product in accord with the endo rule. Replacing the dienophile with maleic acid or fumaric acid (with modified reaction conditions) allows students to discover or verify that the Diels-Alder reaction is stereospecific with respect to the stereochemistry of the alkene. The recording of NMR spectra is a particularly useful means of establishing cis-trans stereochemistry (symmetry) of the products.

  5. Winter behavior and ecology of the Alder Flycatcher (Empidonax alnorum) in Peru

    USGS Publications Warehouse

    Foster, M.S.

    2007-01-01

    The winter ecology and behavior of Alder Flycatchers (Empidonax alnorum) were studied along the Manu, a white-water meander river in Manu National Park, Madre de Dios, Peru during October and November, 1993 to 1997. The birds occupied territories in primary-succession habitats on growing point bars. They were most common in mixed stands of Tessaria integrifolia (Asteraceae) and Gynerium sagittatum (Gramineaceae) interspersed with bare sand areas. The uneven height of the Tessaria canopy, which resulted in openings in the vegetation large enough for the birds to flycatch, was an important habitat feature. Birds obtained insects, which formed about 96% of the diet, by aerial hawking (91%), perch gleaning (6%), and hover gleaning (3%). They also fed on fruit. Territory sizes ranged from 0.04 to 0.25 ha. Of nine territories that we observed closely, six were occupied by two birds each, two by one bird each, and one by three birds. Every territory had one dominant individual who was primarily responsible for territory defense; the other birds were associates. Vocalizations given included the fee-bee-o song, a two-syllable song, and the pit note, which are also given on the breeding grounds. A series of pits given increasingly rapidly signaled a territorial interaction. In aggressive encounters, the birds (1) interacted vocally, remaining on their territories and counter calling or exchanging agitated calls; (2) moved toward a common territorial boundary and engaged in a vocal duel; or (3) the dominant chased intruders out of the territory. Chases were most common when a wave of new birds entered the area. Dominant birds, which sang the full song, were probably adult males. Immature males do not sing a full song, and females are not known to sing in nature. Associate individuals were likely females or young males.

  6. Winter behavior and ecology of the Alder Flycatcher (Empidonax alnorum) in Peru

    USGS Publications Warehouse

    Foster, M.S.

    2007-01-01

    The winter ecology and behavior of Alder Flycatchers (Empidonax alnorum) were studied along the Manu, a white-water meander river in Manu National Park, Madre de Dios, Peru?? during October and November, 1993 to 1997. The birds occupied territories in primary-succession habitats on growing point bars. They were most common in mixed stands of Tessaria integrifolia (Asteraceae) and Gynerium sagittatum (Gramineaceae) interspersed with bare sand areas. The uneven height of the Tessaria canopy, which resulted in openings in the vegetation large enough for the birds to flycatch, was an important habitat feature. Birds obtained insects, which formed about 96% of the diet, by aerial hawking (91%), perch gleaning (6%), and hover gleaning (3%). They also fed on fruit. Territory sizes ranged from 0.04 to 0.25 ha. Of nine territories that we observed closely, six were occupied by two birds each, two by one bird each, and one by three birds. Every territory had one dominant individual who was primarily responsible for territory defense; the other birds were associates. Vocalizations given included the fee-bee-o song, a two-syllable song, nd the pit note, which are also given on the breeding grounds. A series of pits given increasingly rapidly signaled a territorial interaction. In aggressive encounters, the birds (1) interacted vocally, remaining on their territories and counter calling or exchanging agitated calls; (2) moved toward a common territorial boundary and engaged in a vocal duel; or (3) the dominant chased intruders out of the territory. Chases were most common when a wave of new birds entered the area. Dominant birds, which sang the full song, were probably adult males. Immature males do not sing a full song, and females are not known to sing in nature. Associate individuals were likely females or young males. ?? The Neotropical Ornithological Society.

  7. Novel Diels-Alder based self-healing epoxies for aerospace composites

    NASA Astrophysics Data System (ADS)

    Coope, T. S.; Turkenburg, D. H.; Fischer, H. R.; Luterbacher, R.; van Bracht, H.; Bond, I. P.

    2016-08-01

    Epoxy resins containing Diels-Alder (DA) furan and maleimide moieties are presented with the capability to self-heal after exposure to an external heat source. A conventional epoxy amine system has been combined with furfuryl and maleimide functional groups in a two-step process, to avoid major side-reactions, and the concentration of a thermo-reversibly binding cross-linker was considered to balance thermoset and thermoplastic behaviours, and the subsequent self-healing performance. In the context of self-repair technologies an inbuilt ‘intrinsic’ self-healing system is deemed favourable as the healing agent can be placed in known ‘hot spot’ regions (i.e. skin-stringer run outs, ply drops and around drilled holes) where operational damage predominately occurs in load bearing aerospace structures. In this study, the mechanical and self-healing performance of furan functionalised epoxy resins containing varying amounts (10, 20, 30 or 40 pph) of bismaleimide were investigated using a bulk epoxy polymer tapered double cantilever beam test specimen geometry. Two forms, a thin film and a bulk material, were evaluated to account for future integration methods into fibre reinforced polymer (FRP) composites. The highest healing efficiency, with respect to the obtained initial load value, was observed from the 20 pph bulk material derivative. The polymers were successful in achieving consistent multiple (three) healing cycles when heated at 150 °C for 5 min. This novel investigated DA material exhibits favourable processing characteristics for FRP composites as preliminary studies have shown successful coextrution with reinforcing fibres to form free standing films and dry fibre impregnation.

  8. Diels–Alder reactions in confined spaces: the influence of catalyst structure and the nature of active sites for the retro-Diels–Alder reaction

    PubMed Central

    Cantín, Ángel

    2016-01-01

    Summary Diels–Alder cycloaddition between cyclopentadiene and p-benzoquinone has been studied in the confined space of a pure silica zeolite Beta and the impact on reaction rate due to the concentration effect within the pore and diffusion limitations are discussed. Introduction of Lewis or Brønsted acid sites on the walls of the zeolite strongly increases the reaction rate. However, contrary to what occurs with mesoporous molecular sieves (MCM-41), Beta zeolite does not catalyse the retro-Diels–Alder reaction, resulting in a highly selective catalyst for the cycloaddition reaction. PMID:27829925

  9. Effect of Grey Hair Evulsion on the Response to Calcium Pantothenate in Premature Grey Hairs.

    PubMed

    Pasricha, J S

    1986-01-01

    Thirty nine girls between 12 and 31 years in age, having Premature grey hairs were, treated with calcium pantothenate 200 mg, Basiton Forte. (a vitamin B complex formulation), and/or vitamin E 200 mg a day orally, combined with grey hair evulsion which consists of pulling out all the grey hairs along with snipping the converted hairs at the grey black junction, and checking after 3-5 months, the numbers of hairs regrowing as grey hairs, new grey hairs, new converted hairs and the hairs missed during the previous check - ups. This study revealed that following evulsion of grey hairs, all such hairs do not regrow as grey hairs, the per cent rate of regrowth varied between nil and 88.23% during the first recheck, and almost similar results were obtained during further follow up. Out of 7 patients who have been followed up for almost 3 years, the total numbers of grey hairs had decreased from 109 to 15, 47 to 1, 35 to 7, and 242 to 7 in 4 cases, increased from 31 to 108 and 23 to 41 in 2 cases, and remained almost unchanged from 25 to 33 in the seventh case. This response is considered better than the effect of calcium panthothenate used without grey hair evulsion.

  10. Absence of net long-term successional facilitation by alder in a boreal Alaska floodplain.

    PubMed

    Stuart Chapin, F; Conway, Alexandra J; Johnstone, Jill F; Hollingsworth, Teresa N; Hollingsworth, Jamie

    2016-11-01

    Long-term experiments provide a way to test presumed causes of successional or environmentally driven vegetation changes. Early-successional nitrogen (N)-fixing plants are widely thought to facilitate productivity and vegetation development on N-poor sites, thus accounting for observed vegetation patterns later in succession. We tested this facilitative impact on vegetation development in a 23-yr field experiment on an Interior Alaska (USA) floodplain. On three replicate early-successional silt bars, we planted late-successional white spruce (Picea glauca) seedlings in the presence and absence of planted seedlings of an early-successional N-fixing shrub, thinleaf alder (Alnus incana). Alder initially facilitated survivorship and growth of white spruce. Within six years, however, after canopy closure, alder negatively affected spruce survivorship and growth. Our three replicate sites followed different successional trajectories. One site was eliminated by erosion and supported no vegetation development during our study. The other two sites, which differed in site moisture, diverged in vegetation composition. Structural equation modeling (SEM) suggested that, in the drier of these two sites, alder inhibited spruce growth directly (presumably by competition) and indirectly through effects mediated by competition with other woody species. However, at the wetter site, alder had both positive and negative effects on spruce growth, with negative effects predominating. Snowshoe hares (Lepus americanus) in alder thickets further reduced height growth of spruce in the wetter site. We conclude that net effects of alder on white spruce, the late-successional dominant, were primarily inhibitory and indirect, with the mechanisms depending on initial site moisture. Our results highlight the importance of long-term research showing that small differences among initial replicate sites can cause divergence in successional trajectories, consistent with individualistic distributions

  11. Disturbed grey matter coupling in schizophrenia.

    PubMed

    Collin, Guusje; de Reus, Marcel A; Cahn, Wiepke; Hulshoff Pol, Hilleke E; Kahn, René S; van den Heuvel, Martijn P

    2013-01-01

    In schizophrenia, grey matter deficits have been shown for many regions throughout the brain. These regions do not operate in isolation. Rather, they form a structural network of interconnected grey matter regions. To examine the mutual dependence of brain regions, this study investigated interregional coupling in lobar and regional grey matter volumes obtained from 146 schizophrenia patients and 122 healthy comparison subjects. Compared to healthy controls, schizophrenia patients showed both decreased (e.g. between left frontal and bilateral subcortical, p≤0.005) and increased (e.g. between left temporal and bilateral subcortical, p≤0.001) coupling between lobar grey matter volumes. On a regional scale, decreased coupling was most pronounced between fronto-parietal cortical regions and subcortical structures, and between frontal and occipital regions. In addition, an increased association was found among frontal and limbic regions, and for temporo-occipital connexions. Consistent with dysconnectivity theories of schizophrenia, impaired grey matter coupling may be reflective of reduced integrity of the brain's network. Furthermore, as cross-sectional volumetric coupling is indicative of maturational coupling, aberrant grey matter coupling may be a marker of neurodevelopmental abnormalities in schizophrenia.

  12. Standing footprint diagnostic method

    NASA Astrophysics Data System (ADS)

    Fan, Y. F.; Fan, Y. B.; Li, Z. Y.; Newman, T.; Lv, C. S.; Fan, Y. Z.

    2013-10-01

    Center of pressure is commonly used to evaluate standing balance. Even though it is incomplete, no better evaluation method has been presented. We designed our experiment with three standing postures: standing with feet together, standing with feet shoulder width apart, and standing with feet slightly wider than shoulder width. Our platform-based pressure system collected the instantaneous plantar pressure (standing footprint). A physical quantity of instantaneous standing footprint principal axis was defined, and it was used to construct an index to evaluate standing balance. Comparison between results from our newly established index and those from the center of pressure index to evaluate the stability of different standing postures revealed that the standing footprint principal axis index could better respond to the standing posture change than the existing one. Analysis indicated that the insensitive response to the relative position between feet and to the standing posture change from the center of pressure could be better detected by the standing footprint principal axis index. This predicts a wide application of standing footprint principal axis index when evaluating standing balance.

  13. Standing Tall: The Benefits of Standing Devices

    ERIC Educational Resources Information Center

    Warner, Mark P.

    2007-01-01

    In the author's opinion as a pediatric physical therapist, with the exception of a wheelchair, there is no other piece of assistive technology that is more beneficial to children and adults with special needs than a standing device. Postural symmetry during standing and walking activities is extremely important for everyone. Very few children…

  14. Linking Landscape Characteristics and High Stream Nitrogen in the Oregon Coast Range: Red Alder Complicates Use of Nutrient Criteria

    EPA Science Inventory

    Red alder (a nitrogen-fixing tree) and sea salt inputs can strongly influence stream nitrogen concentrations in western Oregon and Washington. We compiled a database of stream nitrogen and landscape characteristics in the Oregon Coast Range. Basal area of alder, expressed as a ...

  15. Diels-Alder reactions: The effects of catalyst on the addition reaction

    NASA Astrophysics Data System (ADS)

    Yilmaz, Özgür; Kus, Nermin Simsek; Tunç, Tuncay; Sahin, Ertan

    2015-10-01

    The reaction between 2,3-dimethyl-1,3-butadiene and dimethyl 7-oxabicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylate is efficiently achieved with small amounts of catalyst, i.e. phenol, AcOH, nafion, and β-cyclodextrin. Exo-diastereoselective cycloaddition reactions were observed both without catalyst and different catalysts for 48 days. As a result, different products (tricyclicmolecule 5, retro-Diels-Alder product 6, and oxidation product 7) were obtained with different catalysts. In addition, we synthesized Diels-Alders product 8 and tricyclocyclitol 10 via Diels-Alder reaction. The structures of these products were characterized by 1H NMR, 13C NMR, MS and IR spectroscopy.

  16. Electrostatic catalysis of a Diels-Alder reaction.

    PubMed

    Aragonès, Albert C; Haworth, Naomi L; Darwish, Nadim; Ciampi, Simone; Bloomfield, Nathaniel J; Wallace, Gordon G; Diez-Perez, Ismael; Coote, Michelle L

    2016-03-03

    It is often thought that the ability to control reaction rates with an applied electrical potential gradient is unique to redox systems. However, recent theoretical studies suggest that oriented electric fields could affect the outcomes of a range of chemical reactions, regardless of whether a redox system is involved. This possibility arises because many formally covalent species can be stabilized via minor charge-separated resonance contributors. When an applied electric field is aligned in such a way as to electrostatically stabilize one of these minor forms, the degree of resonance increases, resulting in the overall stabilization of the molecule or transition state. This means that it should be possible to manipulate the kinetics and thermodynamics of non-redox processes using an external electric field, as long as the orientation of the approaching reactants with respect to the field stimulus can be controlled. Here, we provide experimental evidence that the formation of carbon-carbon bonds is accelerated by an electric field. We have designed a surface model system to probe the Diels-Alder reaction, and coupled it with a scanning tunnelling microscopy break-junction approach. This technique, performed at the single-molecule level, is perfectly suited to deliver an electric-field stimulus across approaching reactants. We find a fivefold increase in the frequency of formation of single-molecule junctions, resulting from the reaction that occurs when the electric field is present and aligned so as to favour electron flow from the dienophile to the diene. Our results are qualitatively consistent with those predicted by quantum-chemical calculations in a theoretical model of this system, and herald a new approach to chemical catalysis.

  17. Validation of the Alder Hey Triage Pain Score

    PubMed Central

    Stewart, B; Lancaster, G; Lawson, J; Williams, K; Daly, J

    2004-01-01

    Aims: To describe the validation and reliability of a new pain tool (the Alder Hey Triage Pain Score, AHTPS) for children at triage in the accident and emergency (A&E) setting. Methods: A new behavioural observational pain tool was developed because of dissatisfaction with available tools and a lack of confidence in self-assessment scores at triage. The study was conducted in a large paediatric A&E department; 575 children (aged 0–16 years) were included. Inter-rater reliability and various aspects of validity were assessed. In addition this tool was compared to the Wong-Baker self-assessment tool.1 The children were concurrently scored by a research nurse and triage nurses to assess inter-rater reliability. Construct validity was assessed by comparing the research nurse's triage score with the research nurse reassessment score after intervention and/or analgesia. Known group construct validity was assessed by comparing the research nurse's score at triage with the level of pain of the condition as judged by the discharge diagnosis. Predictive validity was assessed by comparing the research nurse's AHTPS with the level of analgesia needed by each patient. The AHTPS was also compared to a self-assessment score. Results: A high level of inter-rater reliability, kappa statistic 0.84 (95% CI 0.80 to 0.88), was shown. Construct validity was well demonstrated; known group construct validity and predictive validity were also demonstrated to a varying degree. Conclusions: Results support the use of this observational pain scoring tool in the triage of children in A&E. PMID:15210492

  18. Symmetry-enthalpy correlations in Diels-Alder reactions.

    PubMed

    Tuvi-Arad, Inbal; Avnir, David

    2012-08-06

    Woodward-Hoffmann (WH) rules provide strict symmetry selection rules: when they are obeyed, a reaction proceeds; when they are not obeyed, there is no reaction. However, the voluminous experimental literature provides ample evidence that strict compliance to symmetry requirements is not an obstacle for a concerted reaction to proceed, and therefore the idea has developed that it is enough to have a certain degree of the required symmetry to have reactivity. Here we provide quantitative evidence of that link, and show that as one deviates from the desired symmetry, the enthalpy of activation increases, that is, we show that concerted reactions slow down the further they are from the ideal symmetry. Specifically, we study the deviation from mirror symmetry (evaluated with the continuous symmetry measure (CSM)) of the [4+2] carbon skeleton of the transition state of a series of twelve Diels-Alder reactions in seven different solvents (and in the gas phase), in which the dienes are butadiene, cyclopentadiene, cyclohexadiene, and cycloheptadiene; the dienophiles are the 1-, 1,1-, and 1,1,2-cyanoethylene derivatives; the solvents were chosen to sample a range of dielectric constants from heptane to ethanol. These components provide twenty-four symmetry-enthalpy DFT-calculated correlation lines (out of which only one case is a relatively mild exception) that show the general trend of increase in enthalpy as symmetry decreases. The various combinations between the dienophiles, cyanoethylenes, and solvents provide all kinds of sources for symmetry deviations; it is therefore remarkable that although the enthalpy of activation is dictated by various parameters, symmetry emerges as a primary parameter. In our analysis we also bisected this overall picture into solvent effects and geometry variation effects to evaluate under which conditions the electronic effects are more dominant than symmetry effects.

  19. [Effects of the decomposition of poplar and alder mixed leaf litters on soil microbial biomass].

    PubMed

    Chen, Qin; Fang, Sheng-Zuo; Tian, Ye

    2012-08-01

    An incubation test was conducted to study the effects of the decomposition of poplar and trabeculate alder leaf litters with different mixed ratios and under different application ways on soil microbial biomass carbon (MBC) and nitrogen (MBN). The mixed ratio of the litters had significant effects on soil MBC and MBN. On the 30th day of incubation, soil MBC and MBN were significantly higher in the treatments with > or = 50% of alder litter than in the treatment with poplar litter only and the control. On the 75th day of incubation, the soil MBC in the treatments with > or = 40% of alder litter and the soil MBN in the treatments with > or = 30% of alder litter were significantly greater than those in the treatment with poplar litter only and the control. After 135 days incubation, soil MBC and MBN were significant higher in the treatments with > or = 20% and > or = 40% of alder litter than in the treatment with poplar litter only and the control, respectively. There was no significant difference in the soil MBC/MBN between the treatments with different mixed ratios of poplar and alder leaf litters and the control. Overall, soil MBC/MBN increased during the early period of incubation and decreased in the later period, suggesting that soil microflora changed during the decomposition of the litters. In the whole incubation period, the application ways of the litters had lesser effects on the soil MBC, MBN, and MBC/MBN, indicating that the addition ways of the litters did not affect soil microflora.

  20. Enantioselective Organocatalytic Diels–Alder Trapping of Photochemically Generated Hydroxy‐o‐Quinodimethanes

    PubMed Central

    Dell'Amico, Luca; Vega‐Peñaloza, Alberto; Cuadros, Sara

    2016-01-01

    Abstract The photoenolization/Diels–Alder strategy offers straightforward access to synthetically valuable benzannulated carbocyclic products. This historical light‐triggered process has never before succumbed to efforts to develop an enantioselective catalytic approach. Herein, we demonstrate how asymmetric organocatalysis provides simple yet effective catalytic tools to intercept photochemically generated hydroxy‐o‐quinodimethanes with high stereoselectivity. We used a chiral organic catalyst, derived from natural cinchona alkaloids, to activate maleimides toward highly stereoselective Diels–Alder reactions. An unconventional mechanism of stereocontrol is operative, wherein the organocatalyst is actively involved in both the photochemical pathway, by leveraging the formation of the reactive photoenol, and the stereoselectivity‐defining event. PMID:26797768

  1. Diels–Alder reactions of myrcene using intensified continuous-flow reactors

    PubMed Central

    Álvarez-Diéguez, Miguel Á; Kohl, Thomas M; Tsanaktsidis, John

    2017-01-01

    This work describes the Diels–Alder reaction of the naturally occurring substituted butadiene, myrcene, with a range of different naturally occurring and synthetic dienophiles. The synthesis of the Diels–Alder adduct from myrcene and acrylic acid, containing surfactant properties, was scaled-up in a plate-type continuous-flow reactor with a volume of 105 mL to a throughput of 2.79 kg of the final product per day. This continuous-flow approach provides a facile alternative scale-up route to conventional batch processing, and it helps to intensify the synthesis protocol by applying higher reaction temperatures and shorter reaction times. PMID:28228853

  2. Seepage study for unnamed tributary to Alder Creek, Stevens County, Washington

    USGS Publications Warehouse

    Carpenter, P.J.; Drost, B.W.

    1979-01-01

    Analysis of seepage measurements in the Alder Creek basin, Stevens County, Wash., shows that approximately 50% of 0.2 cubic foot per second taken from an unnamed tributary and used for the 1978 irrigation season would have reached Alder Creek as surface flow. Differences in discharge and specific conductance are explained by the basin geology, physical characteristics, climate, and water use. Only general conclusions could be made from data collected for five seepage measurements because irrigation activities could not be scheduled to allow the hydrologic system to reach equilibrium. (USGS)

  3. Tandem enyne metathesis-Diels-Alder reaction for construction of natural product frameworks.

    PubMed

    Rosillo, Marta; Domínguez, Gema; Casarrubios, Luis; Amador, Ulises; Pérez-Castells, Javier

    2004-03-19

    Enynes connected through aromatic rings are used as substrates for metathesis reactions. The reactivity of three ruthenium carbene complexes is compared. The resulting 1,3-dienes are suitable precursors of polycyclic structures via a Diels-Alder process. Some domino RCM-Diels-Alder reactions are performed, suggesting a possible beneficial effect of the ruthenium catalyst in the cycloaddition process. Other examples require Lewis acid cocatalyst. When applied to aromatic ynamines or enamines, a new synthesis of vinylindoles is achieved. Monitorization of several metathesis reactions with NMR shows the different behavior for ruthenium catalysts. New carbenic species are detected in some reactions with an important dependence on the solvent used.

  4. Stereoselection in Intramolecular Diels-Alder Reactions of 2-Cyano-1-azadienes: Indolizidine and Quinolizidine Synthesis.

    PubMed

    Tay, Gidget C; Sizemore, Nicholas; Rychnovsky, Scott D

    2016-07-01

    Progress toward understanding the scope and diastereoselectivity of intramolecular Diels-Alder reactions using 2-cyano-1-azadienes is described herein. The resulting cyanoenamine products are underutilized intermediates in organic synthesis. Assembly of the Diels-Alder precursors was achieved using an improved imine condensation/oxidative cyanation protocol. By this method, several highly substituted indolizidine and quinolizidine architectures were constructed. Quantum mechanical DFT calculations at the B3LYP/6-31+G(d) level of theory were performed for these cyclizations and provide insights into the origins of the observed diastereoselectivities.

  5. Spinal cord grey matter segmentation challenge.

    PubMed

    Prados, Ferran; Ashburner, John; Blaiotta, Claudia; Brosch, Tom; Carballido-Gamio, Julio; Cardoso, Manuel Jorge; Conrad, Benjamin N; Datta, Esha; Dávid, Gergely; Leener, Benjamin De; Dupont, Sara M; Freund, Patrick; Wheeler-Kingshott, Claudia A M Gandini; Grussu, Francesco; Henry, Roland; Landman, Bennett A; Ljungberg, Emil; Lyttle, Bailey; Ourselin, Sebastien; Papinutto, Nico; Saporito, Salvatore; Schlaeger, Regina; Smith, Seth A; Summers, Paul; Tam, Roger; Yiannakas, Marios C; Zhu, Alyssa; Cohen-Adad, Julien

    2017-03-07

    An important image processing step in spinal cord magnetic resonance imaging is the ability to reliably and accurately segment grey and white matter for tissue specific analysis. There are several semi- or fully-automated segmentation methods for cervical cord cross-sectional area measurement with an excellent performance close or equal to the manual segmentation. However, grey matter segmentation is still challenging due to small cross-sectional size and shape, and active research is being conducted by several groups around the world in this field. Therefore a grey matter spinal cord segmentation challenge was organised to test different capabilities of various methods using the same multi-centre and multi-vendor dataset acquired with distinct 3D gradient-echo sequences. This challenge aimed to characterize the state-of-the-art in the field as well as identifying new opportunities for future improvements. Six different spinal cord grey matter segmentation methods developed independently by various research groups across the world and their performance were compared to manual segmentation outcomes, the present gold-standard. All algorithms provided good overall results for detecting the grey matter butterfly, albeit with variable performance in certain quality-of-segmentation metrics. The data have been made publicly available and the challenge web site remains open to new submissions. No modifications were introduced to any of the presented methods as a result of this challenge for the purposes of this publication.

  6. Test Stand Construction

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Construction crews install steel reinforcing rods at the base of what became the A-2 test stand. The excavation for the stand went down 50 feet with steel H-beams driven 100 feet deeper to form a foundation for the huge piers of the test stand.

  7. Comparative phylogenies and host specialization in the alder ectomycorrhizal fungi Alnicola, Alpova and Lactarius (Basidiomycota) in Europe

    PubMed Central

    2011-01-01

    Background Mycorrhizal fungi form intimate associations with their host plants that constitute their carbon resource and habitat. Alnus spp. (Betulaceae) are known to host an exceptional species-poor and specialized ectomycorrhizal (ECM) fungal community compared to other tree species, but the host-specificity pattern and its significance in terms of fungal diversification and speciation remain poorly documented. The degree of parallel speciation, host switching, and patterns of biogeography were explored in the historical associations between alders and three ECM taxa of Basidiomycetes: Alnicola (Agaricales), Alpova (Boletales), and Lactarius (Russulales). The aim was to develop an evolutionary framework on host specificity and diversification of Basidiomycetes in this highly specialized plant-fungus symbiosis. Results Sporocarps of Alnicola (220), Lactarius (61) and Alpova (29) were collected from stands of the four European alder species (A. alnobetula including the endemic subsp. suaveolens in Corsica, A. cordata, A. glutinosa, A. incana) in Western Europe (mainly in France and Austria), from 1995 to 2009. Specimens were morphologically identified to the species level. From these, 402 sequences of four DNA regions (ITS, rpb2, gpd, and the V9 domain of the mit-SSU rDNA) were successfully obtained and analyzed in addition with 89 sequences available in GenBank and UNITE databases. Phylogenetic analyses were conducted on all sequence data sets (individual and combined) using maximum likelihood reconstruction and Bayesian inference. Fungal phylogenies are compared and discussed in relation to the host, with a focus on species boundaries by associating taxonomic, systematic and molecular information. Conclusions Patterns of host specificity and phylogenies of Alnicola and Lactarius suggest coevolution as a basal factor of speciation in relation with the subgeneric diversification of Alnus, possibly due to the very selective pressure of the host. A second element of

  8. Tularemia without lesions in grey tree squirrels: A diagnostic challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fifteen cases of Francisella tularenesis infection (tularemia) were identified in western grey (Sciurus griseus) and eastern grey (Sciurus carolinesis) squirrels submitted to the Washington Animal Disease Diagnostic Laboratory between 2008 and 2011. All of the squirrels originated in Washington stat...

  9. 36. LARGE MOLD MAKING MACHINE, GREY IRON UNIT #4 SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. LARGE MOLD MAKING MACHINE, GREY IRON UNIT #4 SHOWING PATTERNS THAT FLASKS FIT OVER PRIOR TO BEING FILLED WITH SAND AND COMPRESSED. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  10. 40. THIS TUMBLING MILL IN THE GREY IRON FOUNDRY IS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. THIS TUMBLING MILL IN THE GREY IRON FOUNDRY IS USED TO TUMBLE CASTINGS OVER EACH OTHER TO BREAK OFF RUNNERS AND SPRUES. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  11. Grey matter atrophy in patients suffering from multiple sclerosis.

    PubMed

    Kincses, Zsigmond Tamás; Tóth, Eszter; Bankó, Nóra; Veréb, Dániel; Szabó, Nikoletta; Csete, Gergő; Faragó, Péter; Király, András; Bencsik, Krisztina; Vécsei, László

    2014-09-30

    White matter lesions are defining characteristics of multiple sclerosis (MS), whereas grey matter involvement is a less recognised attribute. Recent investigations using dedicated imaging approaches have made it possible to depict cortical lesions. Additionally, grey matter atrophy may be estimated using various methods. Several studies have suggested that grey matter atrophy closely correlates to clinical disability. In this review we have collected information on grey matter atrophy in MS and the effect of disease modifying therapies upon brain atrophy.

  12. Total synthesis of (±)-epithuriferic acid methyl ester via Diels-Alder reaction.

    PubMed

    Koprowski, Marek; Bałczewski, Piotr; Owsianik, Krzysztof; Różycka-Sokołowska, Ewa; Marciniak, Bernard

    2016-02-07

    In this paper, we have described the first total synthesis of (±)-epithuriferic acid methyl ester from non-natural sources, in four steps (20% overall yield). The key step involves the Diels-Alder reaction of isobenzofuran with methyl 3-(dimethoxyphosphoryl)acrylate which is controlled by "ortho" regio- and endo stereoselectivities due to the COOMe group.

  13. Synthesis and Diels-Alder cycloaddition reaction of norbornadiene and benzonorbornadiene dimers.

    PubMed

    Nişanci, Bilal; Dalkiliç, Erdin; Güney, Murat; Daştan, Arif

    2009-08-11

    Dimeric forms of norbornadiene and benzonorbornadiene were synthesized starting with known monobromide derivatives. The Diels-Alder cycloaddition reaction of dimers with TCNE and PTAD was investigated and new norbornenoid polycyclics were obtained. All compounds were characterized properly using NMR spectroscopy.

  14. Concerning the reactivity of PTAD with isomeric dienes: the mechanism of the Diels-Alder cycloaddition.

    PubMed

    Alberti, Mariza N; Orfanopoulos, Michael

    2009-04-02

    Cyclopropyl substituted dienes are employed as mechanistic probes in the triazolinedione Diels-Alder (DA) reaction. In aprotic and protic solvents, apart from the DA adducts that bear an intact cyclopropyl group, complicated and rearranged products are also obtained. These results provide solid evidence for the involvement of an open intermediate with a lifetime greater than 2 x 10(-12) s.

  15. WATERSHED BIOGEOCHEMISTRY IN THE OREGON COAST RANGE: THE ROLE OF RED ALDER AND SALMON

    EPA Science Inventory

    Variations in plant community composition across the landscape can influence nutrient retention and loss at the watershed scale. A striking example of plant species influence is the role of N2-fixing red alder (Alnus rubra) in the biogeochemistry of Pacific Northwest forests. T...

  16. Arthropod fauna of rolled alder leaves in Washington State, United States of America (Insecta: Arachnida)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alders, Alnus spp., growing on the eastern slopes and foothills of the Cascade Range in Washington State, are often infested with shelter-making (primarily leafrolling) Lepidoptera in the families Tortricidae, Gracillariidae, and Choreutidae. Over a 5 year survey period, 5,172 rolled leaves were ex...

  17. Oxazole as an electron-deficient diene in the Diels-Alder reaction.

    PubMed

    Suárez-Moreno, Galdina Vanessa; González-Zamora, Eduardo; Méndez, Francisco

    2011-12-16

    The Diels-Alder cycloaddition reaction of oxazole with ethylene is facilitated by addition of an alkyl group or Brønsted or Lewis acids to the oxazole nitrogen atom. The efficacy consists of stabilizing the transition state, lowering the activation barrier and the HOMO(dienophile)-LUMO(diene) gap, and increasing the reaction exothermicity.

  18. Biotransformation of a cage-like diels-alder adduct and derivatives by Mucor ramosissimus samutsevitsch

    PubMed Central

    Ito, Felicia Megumi; Mena, Ana Elisa Maciel; Marques, Maria Rita; de Lima, Dênis Pires; Beatriz, Adilson

    2009-01-01

    The present study aimed to evaluate the ability for biotransformation of the Diels-Alder adduct tricyclo[6.2.1.02,7]undeca-4,9-dien-3,6-dione (1) and two synthetic derivatives by the saprobe fungus Mucor ramosissimus Samutsevitsch. Products from oxidation, isomerization and, regioselective and enantioselective reduction were achieved. PMID:24031400

  19. Enantioselective Synthesis of (+)-Estrone Exploiting a Hydrogen Bond-Promoted Diels−Alder Reaction

    PubMed Central

    2010-01-01

    Starting from Dane’s diene and methylcyclopentenedione, (+)-estrone is synthesized along the Quinkert−Dane route in 24% total yield. The key step is an enantioselective Diels−Alder reaction promoted by an amidinium catalyst as efficiently as by a traditional Ti-TADDOLate Lewis acid. PMID:20302330

  20. Scope of the Inverse Electron Demand Diels-Alder Reactions of 1,2,3-Triazine

    PubMed Central

    Anderson, Erin D.; Boger, Dale L.

    2011-01-01

    An examination of the scope of the inverse electron demand Diels–Alder reactions of the parent unsubstituted 1,2,3-triazine is described including the first report of its unique capabilities for participating in previously unexplored [4 + 2] cycloaddition reactions with heterodienophiles. PMID:21488676

  1. High-pressure Diels-Alder approach to natural kainic acid.

    PubMed

    Pandey, Sushil K; Orellana, Arturo; Greene, Andrew E; Poisson, Jean-François

    2006-11-23

    The first Diels-Alder based synthesis of (-)-kainic acid is described. Danishefsky's diene and a vinylogous malonate derived from 4-hydroxyproline combine under high pressure to afford a key bicyclic intermediate with virtually no loss of enantiopurity. This adduct can be converted into the natural product with complete stereocontrol. [reaction: see text].

  2. A Computational Experiment of the Endo versus Exo Preference in a Diels-Alder Reaction

    ERIC Educational Resources Information Center

    Rowley, Christopher N.; Woo, Tom K.

    2009-01-01

    We have developed and tested a computational laboratory that investigates an endo versus exo Diels-Alder cycloaddition. This laboratory employed density functional theory (DFT) calculations to study the cycloaddition of N-phenylmaleimide to furan. The endo and exo stereoisomers of the product were distinguished by building the two isomers in a…

  3. Synthesis of isoquinuclidines from highly substituted dihydropyridines via the Diels-Alder reaction.

    PubMed

    Martin, Rhia M; Bergman, Robert G; Ellman, Jonathan A

    2013-02-01

    A stereo- and regioselective Diels-Alder reaction for the synthesis of highly substituted isoquinuclidines from dihydropyridines and electron-deficient alkenes has been developed. While reactions with activated dienophiles proceed readily under thermal conditions, the use of Lewis acid additives is necessary to facilitate cycloadditions for less reactive alkenes. This procedure affords the target compounds in high yields and diastereoselectivities.

  4. NORTHEAST VIEW OF FOUNDRY FROM TOP OF GREY IRON CUPOLA ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTHEAST VIEW OF FOUNDRY FROM TOP OF GREY IRON CUPOLA SHOWING CORE ROOM ROOF DIRECTLY NORTHEAST, GREY IRON FOUNDRY TO THE RIGHT, MALLEABLE IRON CUPOLAS AND FOUNDRY NORTHEAST OF GREY IRON FOUNDRY WITH THE BRASS FOUNDRY IN THE REAR. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  5. 24. INTERIOR VIEW WITH UNIT NO. 2 GREY IRON DISAMATIC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. INTERIOR VIEW WITH UNIT NO. 2 GREY IRON DISAMATIC SETTING A 1 X 1/2 INCH ELBOW PIPE FITTING, A 'GREY IRON EL', THROUGH AN AUTOMATED PROCESS. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  6. 23. INTERIOR VIEW WITH UNIT NO. 2 GREY IRON DISAMATIC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. INTERIOR VIEW WITH UNIT NO. 2 GREY IRON DISAMATIC SETTING A 1 X 1/2 INCH ELBOW PIPE FITTING, A 'GREY IRON EL'. THIS MACHINE SETS CORES THROUGH AN AUTOMATED PROCESS. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  7. 78 FR 17183 - Information Collection: Grey Towers Visitor Comment Card

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-20

    ... Forest Service Information Collection: Grey Towers Visitor Comment Card AGENCY: Forest Service, USDA... collection 0596- 0222, ``Grey Towers Visitor Comment Card'' with 0596-0226, ``Forest Service Generic... addressed to Nicole Bernarsky, USDA Forest Service, Grey Towers National Historic Site, P.O. Box...

  8. Searching for Grey Literature for Systematic Reviews: Challenges and Benefits

    ERIC Educational Resources Information Center

    Mahood, Quenby; Van Eerd, Dwayne; Irvin, Emma

    2014-01-01

    There is ongoing interest in including grey literature in systematic reviews. Including grey literature can broaden the scope to more relevant studies, thereby providing a more complete view of available evidence. Searching for grey literature can be challenging despite greater access through the Internet, search engines and online bibliographic…

  9. Grey Documentation as a Knowledge Base in Social Work.

    ERIC Educational Resources Information Center

    Berman, Yitzhak

    1994-01-01

    Defines grey documentation as documents issued informally and not available through normal channels and discusses the role that grey documentation can play in the social work knowledge base. Topics addressed include grey documentation and science; social work and the empirical approach in knowledge development; and dissemination of grey…

  10. Knowledge Transfer in Social Work: The Role of Grey Documentation.

    ERIC Educational Resources Information Center

    Berman, Yitzhak

    1995-01-01

    Discusses scholarly journals in the field of social work, information sources for social work practitioners versus researchers, and grey documentation as an alternative means of knowledge transfer. Highlights include research versus practice; grey documentation and scientific credibility; and dissemination of grey literature. (LRW)

  11. Changes in sediment volume in Alder Lake, Nisqually River Basin, Washington, 1945-2011

    USGS Publications Warehouse

    Czuba, Jonathan A.; Olsen, Theresa D.; Czuba, Christiana R.; Magirl, Christopher S.; Gish, Casey C.

    2012-01-01

    The Nisqually River drains the southwest slopes of Mount Rainier, a glaciated stratovolcano in the Cascade Range of western Washington. The Nisqually River was impounded behind Alder Dam when the dam was completed in 1945 and formed Alder Lake. This report quantifies the volume of sediment deposited by the Nisqually and Little Nisqually Rivers in their respective deltas in Alder Lake since 1945. Four digital elevation surfaces were generated from historical contour maps from 1945, 1956, and 1985, and a bathymetric survey from 2011. These surfaces were used to compute changes in sediment volume since 1945. Estimates of the volume of sediment deposited in Alder Lake between 1945 and 2011 were focused in three areas: (1) the Nisqually River delta, (2) the main body of Alder Lake, along a 40-meter wide corridor of the pre-dam Nisqually River, and (3) the Little Nisqually River delta. In each of these areas the net deposition over the 66-year period was 42,000,000 ± 4,000,000 cubic meters (m3), 2,000,000 ± 600,000 m3, and 310,000 ± 110,000 m3, respectively. These volumes correspond to annual rates of accumulation of 630,000 ± 60,000 m3/yr, 33,000 ± 9,000 m3/yr, and 4,700 ± 1,600 m3/yr, respectively. The annual sediment yield of the Nisqually (1,100 ± 100 cubic meters per year per square kilometer [(m3/yr)/km2]) and Little Nisqually River basins [70 ± 24 (m3/yr)/km2] provides insight into the yield of two basins with different land cover and geomorphic processes. These estimates suggest that a basin draining a glaciated stratovolcano yields approximately 15 times more sediment than a basin draining forested uplands in the Cascade Range. Given the cumulative net change in sediment volume in the Nisqually River delta in Alder Lake, the total capacity of Alder Lake since 1945 decreased about 3 percent by 1956, 8 percent by 1985, and 15 percent by 2011.

  12. Grey matter heterotopia: an unusual association of intractable epilepsy.

    PubMed

    Stafford Johnson, D B; Brennan, P; Dwyer, A J; Toland, J

    1997-01-01

    Heterotopic grey matter is an abnormality of neuronal migration that has been reported in association with refractory epilepsy. In this study we reviewed the magnetic resonance (MR) imaging records of all patients undergoing MR scanning for evaluation of intractable epilepsy and identified sixteen patients who had grey matter heterotopia. The distribution of the grey matter heterotopia was periventricular in 9 patients, laminar in 3 and was in a "band" form in 4 patients. Congenital anomalies associated with grey matter heterotopia in this study included polymicrogyria in one patient and absence of the corpus callosum in 2 patients. Grey matter heterotopia is an important MR finding in patients with intractable epilepsy.

  13. Evaluation of appropriate technologies for grey water treatments and reuses.

    PubMed

    Li, Fangyue; Wichmann, Knut; Otterpohl, Ralf

    2009-01-01

    As water is becoming a rare resource, the onsite reuse and recycling of grey water is practiced in many countries as a sustainable solution to reduce the overall urban water demand. However, the lack of appropriate water quality standards or guidelines has hampered the appropriate grey water reuses. Based on literature review, a non-potable urban grey water treatment and reuse scheme is proposed and the treatment alternatives for grey water reuse are evaluated according to the grey water characteristics, the proposed standards and economical feasibility.

  14. Effect of Counterion Structure on Rates and Diastereoselectivities in α,β-Unsaturated Iminium-Ion Diels-Alder Reactions

    PubMed Central

    Marcoux, David; Bindschädler, Pascal; Speed, Alexander W. H.; Chiu, Anna; Pero, Joseph E.; Borg, George A.; Evans, David A.

    2012-01-01

    The use of cyclic α,β-unsaturated iminium-ion dienophiles is documented in two highly diastereoselective Diels-Alder (DA) reactions. The dienophilic counterion was found to have a significant effect on reactivity. PMID:21678927

  15. New domino transposition/intramolecular Diels-Alder reaction in monocyclic allenols: a general strategy for tricyclic compounds.

    PubMed

    Alcaide, Benito; Almendros, Pedro; Aragoncillo, Cristina; Redondo, María C

    2002-07-21

    A novel and direct synthetic strategy to prepare fused tricycles has been developed from monocyclic allenols, masked functionalized dienes, which underwent a domino allenol transposition/intramolecular Diels-Alder reaction.

  16. Saw gin stands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The saw gin stand is the heart of the saw ginning system. Almost from the initial filing of patents for the spiked tooth gin and the saw gin in 1794 and 1796 by Whitney and then Holmes respectively (Hughs and Holt, 2015), the saw gin stand has predominated over early roller-type gins in the U.S. co...

  17. Planter unit test stand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A planter test stand was developed to evaluate individual row-crop metering units in early 2013. This test stand provided the ability to quantify actual seed metering in terms of population, seed spacing, skips, and multiples over a range of meter RPMs and vacuum pressures. Preliminary data has been...

  18. Growth of fullerene fragments using the Diels-Alder cycloaddition reaction: first step towards a C60 synthesis by dimerization.

    PubMed

    Mojica, Martha; Méndez, Francisco; Alonso, Julio A

    2013-02-13

    Density Functional Theory has been used to model the Diels-Alder reactions of the fullerene fragments triindenetriphenilene and pentacyclopentacorannulene with ethylene and 1,3-butadiene. The purpose is to prove the feasibility of using Diels-Alder cycloaddition reactions to grow fullerene fragments step by step, and to dimerize fullerene fragments, as a way to obtain C₆₀. The dienophile character of the fullerene fragments is dominant, and the reaction of butadiene with pentacyclopentacorannulene is favored.

  19. Field reflectance calibration with grey standard reflectors

    NASA Astrophysics Data System (ADS)

    Philipson, Warren R.; Gordon, Daniel K.; Philpot, William D.; Duggin, Michael J.

    1989-06-01

    Spectral reflectances of natural targets are measured in comparison with white standards, even when target reflectances are substantially different from those of the white standards. With some targets, the differences are sufficient to require a change in radiometer gain settings. Under these circumstances, measurement errors could likely be reduced if calibration were with standards whose reflectances were closer to those of the targets. This paper describes field testing that compared a black and a grey standard with a white barium sulphate standard. Variations in the reflectance properties of the black and grey standards, although higher than variations in the white standard, were less than 6 percent. The availability and use of such standards would simplify and increase the accuracy of field measurements.

  20. Silvery grey hair: clue to diagnose immunodeficiency.

    PubMed

    Sahana, Ms; Sacchidanand, S; Hiremagalore, R; Asha, Gs

    2012-04-01

    Silvery hair is a common presentation of rare group of autosomal recessive disorders called Silvery hair syndromes including Griscelli syndrome (GS), Chediak-Higashi syndrome, and Elejalde syndrome. GS is characterized by a silvery grey sheen to hair, large clumped melanosomes in hair shaft, partial albinism, and variable cellular immunodeficiency. We report two cases of GS with classical clinical features and confirmatory findings by microscopic skin and hair examination.

  1. Phylogeny and vicariant speciation of the Grey Rhebok, Pelea capreolus

    PubMed Central

    Robinson, T J; Cernohorska, H; Diedericks, G; Cabelova, K; Duran, A; Matthee, C A

    2014-01-01

    A South African endemic antelope, the Grey Rhebok (Pelea capreolus), has long been an evolutionary enigma in bovid systematics—its phylogenetic intractability attributed to its curious combination of derived and primitive morphological attributes and the consequences of a rapid radiation. By using a combination of DNA sequences, chromosomal characteristics and quantitative and qualitative morphological features we show that the species is a sister taxon to a clade that comprises the waterbuck, reedbuck and allies. Our finding of few unambiguous synapomorphies reinforces suggestions of a rapid radiation and highlights the effects of incomplete lineage sorting, including the hemiplasic nature of several chromosomal rearrangements. We investigate these data to address the general question of what may have led to Pelea being both genetically and ecologically distinct from the Reduncini. We argue that its adaptation to exposed habitats, free of standing water, arose by vicariance prompted by increasing aridity of the extreme south/southwestern region of the African continent in the Miocene. Ancestral lineages leading to the extant Redunca and Kobus, on the other hand, retreated to water-abundant refugia in the north during these mostly globally cool phases. The mosaic of water-rich environments provided by the Okavango and the drainage systems in the southwestern extension of the East African Rift system are considered to have facilitated speciation and chromosomal evolution within these antelope. PMID:24281547

  2. Polar Diels-Alder reactions using electrophilic nitrobenzothiophenes. A combined experimental and DFT study

    NASA Astrophysics Data System (ADS)

    Della Rosa, Claudia D.; Mancini, Pedro M. E.; Kneeteman, Maria N.; Lopez Baena, Anna F.; Suligoy, Melisa A.; Domingo, Luis R.

    2015-01-01

    The reactions between 2- and 3-nitrobenzothiophenes with three dienes of different nucleophilicity, 1-methoxy-3-trimethylsilyloxy-1,3-butadiene, 1-trimethylsilyloxy-1,3-butadiene and isoprene developed in anhydrous benzene and alternative under microwave irradiation with molecular solvents or in free solvent conditions, respectively, for produce dibenzothiophenes permit to conclude that both nitroheterocycles act as electrophile with the cited dienes. In the cases of the dienes 1-methoxy-3-trimethylsilyloxy-1,3-butadiene and 1-trimethylsilyloxy-1,3-butadiene which posses major nucleophilicity the observed product is the normal cycloaddition one. However when the diene is isoprene the product with both electrophiles follow the hetero Diels-Alder way. These reactions are considered polar cycloaddition reactions and the yields are reasonables. Moreover the polar Diels-Alder reactions of nitrobenzothiophenes with electron rich dienes 1-trimethylsilyloxy-1,3-butadiene have been theoretically studied using DFT methods.

  3. Origins of Stereoselectivity in Diels-Alder Cycloadditions Catalyzed by Chiral Imidazolidinones

    PubMed Central

    Gordillo, Ruth; Houk, K. N.

    2011-01-01

    B3LYP/6-31G(d) density functional theory has been used to study Diels-Alder reactions of cyclopentadiene with α,β-unsaturated aldehydes and ketones organocatalyzed by MacMillan’s chiral imidazolidinones. Preferred conformations of transition structures and reaction intermediates have been located. The dramatically different reactivities and enantioselectivities exhibited by two similar chiral imidazolidinones are rationalized. PMID:16536527

  4. The unexpected product of Diels-Alder reaction between "indanocyclon" and maleimide

    NASA Astrophysics Data System (ADS)

    Dobrowolski, Michał A.; Roszkowski, Piotr; Struga, Marta; Szulczyk, Daniel

    2017-02-01

    A heterocyclic compound commonly known as "indanocyclon" undergoes an unexpected Diels-Alder addition with maleimide. The resulting product has been isolated and characterized in order to get an information about its structure and possible mechanism of the reaction. Extensive comparison of single crystal properties of 3-(2,8-dioxo-1,3-diphenyl-2,8-dihydrocyclopenta[a]inden-8a(1H)-yl)pyrrolidine-2,5-dione and favorable product of the reaction has been also performed.

  5. Control of femtosecond laser driven retro-Diels-Alder-like reaction of dicyclopentadiene

    NASA Astrophysics Data System (ADS)

    Das, Dipak Kumar; Goswami, Tapas; Goswami, Debabrata

    2010-12-01

    Using femtosecond time resolved degenerate pump-probe mass spectrometry coupled with simple linearly chirped frequency modulated pulse, we elucidate that the dynamics of retro-Diels-Alder reaction of diclopentadiene (DCPD) to cyclopentadiene (CPD) in supersonic molecular beam occurs in ultrafast time scale. Negatively chirped pulse enhances the ion yield of CPD, as compared to positively chirped pulse. This indicates that by changing the frequency (chirp) of the laser pulse we can control the ion yield of a chemical reaction.

  6. Intramolecular Diels–Alder Reactions of Cycloalkenones: Stereoselectivity, Lewis Acid Acceleration, and Halogen Substituent Effects

    PubMed Central

    2015-01-01

    The intramolecular Diels–Alder reactions of cycloalkenones and terminal dienes occur with high endo stereoselectivity, both thermally and under Lewis-acidic conditions. Through computations, we show that steric repulsion and tether conformation govern the selectivity of the reaction, and incorporation of either BF3 or α-halogenation increases the rate of cycloaddition. With a longer tether, isomerization from a terminal diene to the more stable internal diene results in a more facile cycloaddition. PMID:24410341

  7. Diels-Alder reactions as an efficient route to high purity cyclic polymers.

    PubMed

    Glassner, Mathias; Blinco, James P; Barner-Kowollik, Christopher

    2011-05-18

    A simple and efficient route for the synthesis of cyclic polymer systems is presented. Linear furan protected α-maleimide-ω-cyclopentadienyl functionalized precursors (poly(methyl methacrylate) and poly(tert-butyl acrylate)) were synthesized via atom transfer radical polymerization (ATRP) and subsequent substitution of the bromine end-group with cyclopentadiene. Upon heating at high dilution, deprotection of the dieneophile occurs followed by an intramolecular Diels-Alder reaction yielding a high purity cyclic product.

  8. Acid-free aza Diels-Alder reaction of Danishefsky's diene with imines.

    PubMed

    Yuan, Yu; Li, Xin; Ding, Kuiling

    2002-09-19

    [reaction: see text] A highly efficient aza Diels-Alder reaction of Danishefsky's diene with imines was found to occur in methanol in the absence of any acids at room temperature to give corresponding 2-substituted dihydro-4-pyridone derivatives in high yields. This reaction can be also carried out in a three-component one-pot reaction manner. The reaction was found to proceed through a Mannich-type condensation mechanism.

  9. Biomass of Speckled Alder on an Air-Polluted Mountain Site and its Response to Fertilization

    NASA Astrophysics Data System (ADS)

    Kuneš, Ivan; Baláš, Martin; Koňasová, Tereza; Špulák, Ondřej; Balcar, Vratislav; Millerová, Kateřina Bednářová; Kacálek, Dušan; Jakl, Michal; Zahradník, Daniel; Vítámvás, Jan; Š´astná, Jaroslava; Jaklová Dytrtová, Jana

    2014-12-01

    The article summarizes outcomes of a biomass study conducted in a young speckled alder plantation on a cold mountain site. At this location, the previously existing old forest was clear felled because of damage from air pollution, and present-day surface humus is in need of restoration. The intention of this study was to quantify the biomass and nutrients accumulated by alders and their components and assess whether the initial fertilization resulted in increased biomass production and nutrient accumulation in the biomass. Besides the control, two fertilized treatments were installed. In the surface treatment (SUT), the amendment was applied as a base dressing in small circles around trees. In the planting-hole treatment (PHT), the amendment was incorporated into soil inside the planting holes. Five growth seasons after planting and fertilization, six alders from each treatment were harvested including roots. Their biomass was quantified and analyzed for macroelements. The greatest pool of dry mass (DM) was branches in the control and stem wood in the fertilized treatments. The greatest pools of macroelements were leaves and branches. The most pronounced effects of fertilization were recorded in the DM and consequently in the absolute quantities of nutrients. The DM of an average tree in the control, SUT, and PHT was 85, 226, and 231 g, respectively. The absolute contents of nutrients per tree in the fertilized treatments showed the following increases, as compared with the control: (N) 2.5-2.6 times; (P) 1.6-2.4 times; (K) 1.8-2.1 times; and (Mg) 1.8-2.0 times, respectively. Speckled alder responded positively to fertilization.

  10. Light-induced hetero-Diels-Alder cycloaddition: a facile and selective photoclick reaction.

    PubMed

    Arumugam, Selvanathan; Popik, Vladimir V

    2011-04-13

    2-Napthoquinone-3-methides (oNQMs) generated by efficient photodehydration (Φ=0.2) of 3-(hydroxymethyl)-2-naphthol undergo facile hetero-Diels-Alder addition (k(D-A)∼ 4×10(4) M(-1) s(-1)) to electron-rich polarized olefins in an aqueous solution. The resulting photostable benzo[g]chromans are produced in high to quantitative yield. The unreacted oNQM is rapidly hydrated (k(H2O) ∼145 s(-1)) to regenerate the starting diol. This competition between hydration and cycloaddition makes oNQMs highly selective, since only vinyl ethers and enamines are reactive enough to form the Diels-Alder adduct in an aqueous solution; no cycloaddition was observed with other types of alkenes. To achieve photolabeling or photoligation of two substrates, one is derivatized with a vinyl ether moiety, while 3-(hydroxymethyl)-2-naphthol is attached to the other via an appropriate linker. The light-induced Diels-Alder "click" strategy permits the formation of either a permanent or hydrolytically labile linkage. Rapid kinetics of this photoclick reaction (k=4×10(4) M(-1) s(-1)) is useful for time-resolved applications. The short lifetime (τ ∼7 ms in H(2)O) of the active form of the photoclick reagent prevents its migration from the site of irradiation, thus, allowing for spatial control of the ligation or labeling.

  11. Factors for converting hazelnut (Corylus avellana L) into black alder (Alnus glutinosa Yalt.) plantations.

    PubMed

    Durkaya, Ali; Durkaya, Birsen

    2009-07-01

    Hazelnut plantations, which are a major source of income for the villagers in the eastern Black sea region are notable to provide sufficient income to the villagers due to price fluctuations and sudden falls witnessed in recent years. Alternative investments in place of hazelnut cultivation are being investigated in order to prevent migration to urban areas and to increase the welfare of the rural population in the region. Black alder plantation investments have been assessed as one of the most essential alternative investment tools within the framework of the study Assessment was carried out by comparing expected possible net present values (NPV). Although value increase occurs 12-18 years later more income can be obtained through black alder than hazelnut plantation. In hazelnut plantations, the best NPV emerged in the lower zone. NPV was positive in the moderate zone but values were close to zero. In upper zone, positive NPV couldn't emerge. As a result, it was understood that black alder plantation investment is an effective alternative for hazelnut plantations.

  12. NEO Test Stand Analysis

    NASA Technical Reports Server (NTRS)

    Pike, Cody J.

    2015-01-01

    A project within SwampWorks is building a test stand to hold regolith to study how dust is ejected when exposed to the hot exhaust plume of a rocket engine. The test stand needs to be analyzed, finalized, and fabrication drawings generated to move forward. Modifications of the test stand assembly were made with Creo 2 modeling software. Structural analysis calculations were developed by hand to confirm if the structure will hold the expected loads while optimizing support positions. These calculations when iterated through MatLab demonstrated the optimized position of the vertical support to be 98'' from the far end of the stand. All remaining deflections were shown to be under the 0.6'' requirement and internal stresses to meet NASA Ground Support Equipment (GSE) Safety Standards. Though at the time of writing, fabrication drawings have yet to be generated, but are expected shortly after.

  13. Exploring the origins of grey matter damage in multiple sclerosis.

    PubMed

    Calabrese, Massimiliano; Magliozzi, Roberta; Ciccarelli, Olga; Geurts, Jeroen J G; Reynolds, Richard; Martin, Roland

    2015-03-01

    Multiple sclerosis is characterized at the gross pathological level by the presence of widespread focal demyelinating lesions of the myelin-rich white matter. However, it is becoming clear that grey matter is not spared, even during the earliest phases of the disease. Furthermore, grey matter damage may have an important role both in physical and cognitive disability. Grey matter pathology involves both inflammatory and neurodegenerative mechanisms, but the relationship between the two is unclear. Histological, immunological and neuroimaging studies have provided new insight in this rapidly expanding field, and form the basis of the most recent hypotheses on the pathogenesis of grey matter damage.

  14. Searching for grey literature for systematic reviews: challenges and benefits.

    PubMed

    Mahood, Quenby; Van Eerd, Dwayne; Irvin, Emma

    2014-09-01

    There is ongoing interest in including grey literature in systematic reviews. Including grey literature can broaden the scope to more relevant studies, thereby providing a more complete view of available evidence. Searching for grey literature can be challenging despite greater access through the Internet, search engines and online bibliographic databases. There are a number of publications that list sources for finding grey literature in systematic reviews. However, there is scant information about how searches for grey literature are executed and how it is included in the review process. This level of detail is important to ensure that reviews follow explicit methodology to be systematic, transparent and reproducible. The purpose of this paper is to provide a detailed account of one systematic review team's experience in searching for grey literature and including it throughout the review. We provide a brief overview of grey literature before describing our search and review approach. We also discuss the benefits and challenges of including grey literature in our systematic review, as well as the strengths and limitations to our approach. Detailed information about incorporating grey literature in reviews is important in advancing methodology as review teams adapt and build upon the approaches described.

  15. Grey Hair Evlsion Technique For Evaluating the Effect of Drugs For the Treatment of Premature Grey Hairs.

    PubMed

    Pasricha, J S

    1985-01-01

    An improved method for evaluating the effect of treatment for premature grey hairs is described. The method consists of pulling out all the grey hairs in a patient and counting the number removed. Simultaneously, the converted hairs are also snipped at the grey-black junction and counted. After a gap of 3 months, the survey is repeated to count the number of hairs which have regrowing as grey hairs, the hairs which have become grey and also the hairs which have got converted into black during this period. Such surveys are repeated at 3 months intervals over a period of several years to see the progress of greying of hair in an individual and to evaluate the effect of various therapeutic procedures.

  16. Grey('s) Identity: Complications of Learning and Becoming in a Popular Television Show

    ERIC Educational Resources Information Center

    Jubas, Kaela

    2013-01-01

    In this article, the author outlines an analysis of the American show "Grey's Anatomy" as an example of how popular culture represents identity and the process of professional identity construction in a medical workplace, particularly the surgical service of a large urban hospital. In discussing identity, she connects professional identity to…

  17. Looking northeast from Test Stand 'A' superstructure towards Test Stand ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking northeast from Test Stand 'A' superstructure towards Test Stand 'D' tower (4223/E-24, left background), Test Stand 'C' tower (4217/E-18, center), and Test Stand 'B' (4215/E-16, right foreground). - Jet Propulsion Laboratory Edwards Facility, Edwards Air Force Base, Boron, Kern County, CA

  18. PPT Thrust Stand

    NASA Technical Reports Server (NTRS)

    Haag, Thomas W.

    1995-01-01

    A torsional-type thrust stand has been designed and built to test Pulsed Plasma Thrusters (PPT's) in both single shot and repetitive operating modes. Using this stand, momentum per pulse was determined strictly as a function of thrust stand deflection, spring constant, and natural frequency. No empirical corrections were required. The accuracy of the method was verified using a swinging impact pendulum. Momentum transfer data between the thrust stand and the pendulum were consistent to within 1%. Following initial calibrations, the stand was used to test a Lincoln Experimental Satellite (LES-8/9) thruster. The LES-8/9 system had a mass of approximately 7.5 kg, with a nominal thrust to weight ratio of 1.3 x 10(exp -5). A total of 34 single shot thruster pulses were individually measured. The average impulse bit per pulse was 266 microN-s, which was slightly less than the value of 300 microN-s published in previous reports on this device. Repetitive pulse measurements were performed similar to ordinary steady-state thrust measurements. The thruster was operated for 30 minutes at a repetition rate of 132 pulses per minute and yielded an average thrust of 573 microN. Using average thrust, the average impulse bit per pulse was estimated to be 260 microN-s, which was in agreement with the single shot data. Zero drift during the repetitive pulse test was found to be approximately 1% of the measured thrust.

  19. Standing wave compressor

    DOEpatents

    Lucas, Timothy S.

    1991-01-01

    A compressor for compression-evaporation cooling systems, which requires no moving parts. A gaseous refrigerant inside a chamber is acoustically compressed and conveyed by means of a standing acoustic wave which is set up in the gaseous refrigerant. This standing acoustic wave can be driven either by a transducer, or by direct exposure of the gas to microwave and infrared sources, including solar energy. Input and output ports arranged along the chamber provide for the intake and discharge of the gaseous refrigerant. These ports can be provided with optional valve arrangements, so as to increase the compressor's pressure differential. The performance of the compressor in either of its transducer or electromagnetically driven configurations, can be optimized by a controlling circuit. This controlling circuit holds the wavelength of the standing acoustical wave constant, by changing the driving frequency in response to varying operating conditions.

  20. Standing equine sinus surgery.

    PubMed

    Barakzai, Safia Z; Dixon, Padraic M

    2014-04-01

    Trephination of the equine sinuses is a common surgical procedure in sedated standing horses. Standing sinus flap surgery has become increasingly popular in equine referral hospitals and offers several advantages over sinusotomy performed under general anesthesia, including reduced patient-associated risks and costs; less intraoperative hemorrhage, allowing better visualization of the operative site; and allows surgeons to take their time. Other minimally invasive surgical procedures include sinoscopic surgery, balloon sinuplasty, and transnasal laser sinonasal fenestration. Despite the procedure used, appropriate indications for surgery, good patient selection, and familiarity with regional anatomy and surgical techniques are imperative for good results.

  1. 11. INTERIOR VIEW WITH JAMES WILLIAMS INSIDE GREY IRON UNIT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. INTERIOR VIEW WITH JAMES WILLIAMS INSIDE GREY IRON UNIT NO. 1 MOLDING CONVEYOR, AIR CLEANING A PATTERN AS IT SITS WITHIN A FLASK ON A MOLDING MACHINE PRIOR TO BEING FILLED WITH SAND FROM THE OVERHEAD CONVEYOR. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  2. 17. INTERIOR VIEW WITH GREY UNIT NO. 1 MOLD CONVEYOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. INTERIOR VIEW WITH GREY UNIT NO. 1 MOLD CONVEYOR SHOWING CHAIN HELD WEIGHTS THAT TRAVEL AT THE SAME SPEED AS THE CONVEYOR AND REST ON COMPLETED MOLDS TO HOLD THE SAND SEAMS TOGETHER AS MOLTED IRON IS POURED INTO THE MOLD CAVITY. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  3. 28. CORE STORAGE AREA OF THE GREY IRON FOUNDRY SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. CORE STORAGE AREA OF THE GREY IRON FOUNDRY SHOWING CORES THAT WILL BE USED TO CREATE INTERIOR WALLS OF SMALL BALL VALVES, FOREGROUND, AND LARGE GATE VALVES, BACKGROUND. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  4. 31. PETIBONE SAND THROWING MACHINE BOX FLOOR GREY IRON FOUNDRY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. PETIBONE SAND THROWING MACHINE BOX FLOOR GREY IRON FOUNDRY FORCES CONDITIONED MOLDING SAND, AT HIGH VELOCITY, INTO MOLDS TOO BIG TO BE MADE ON ONE OF THE CONVEYOR SYSTEMS. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  5. A High Precision Prediction Model Using Hybrid Grey Dynamic Model

    ERIC Educational Resources Information Center

    Li, Guo-Dong; Yamaguchi, Daisuke; Nagai, Masatake; Masuda, Shiro

    2008-01-01

    In this paper, we propose a new prediction analysis model which combines the first order one variable Grey differential equation Model (abbreviated as GM(1,1) model) from grey system theory and time series Autoregressive Integrated Moving Average (ARIMA) model from statistics theory. We abbreviate the combined GM(1,1) ARIMA model as ARGM(1,1)…

  6. 30. NATIONAL SHELL CORE MACHINE IN THE GREY IRON FOUNDRY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. NATIONAL SHELL CORE MACHINE IN THE GREY IRON FOUNDRY AUTOMATICALLY INJECTS SAND INTO CLOSED, HEATED CORE BOXES THAT SET THE RESINS AND PERMIT A HARDENED CORE TO BE REMOVED BY THE OPERATOR. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  7. 34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES CORES THAT ARE NOT MADE ON HEATED OR COLD BOX CORE MACHINES, TO SET BINDING AGENTS MIXED WITH THE SAND CREATING CORES HARD ENOUGH TO WITHSTAND THE FLOW OF MOLTEN IRON INSIDE A MOLD. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  8. 8. INTERIOR VIEW, LOOKING WEST, WITH GREY IRON HOLDING FURNACES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. INTERIOR VIEW, LOOKING WEST, WITH GREY IRON HOLDING FURNACES AND AN IRON POUR IN PROCESS, CUPOLA TENDER RICHARD SLAUGHTER SUPERVISING THE POUR. MOLTEN DUCTILE IRON IS POURED FROM THIS 25-TON HOLDING FURNACE INTO LADLES FOR TRANSPORT TO CASTING STATIONS. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  9. 32. LARGE LADLE, BOX FLOOR, GREY IRON FOUNDRY IS USED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. LARGE LADLE, BOX FLOOR, GREY IRON FOUNDRY IS USED TO CARRY LARGE BATCHES OF IRON FROM THE CUPOLA AREAS TO THE LARGE MOLDS MADE ON BOX FLOOR AREA. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  10. 41. INTERIOR VIEW, LOOKING WEST, WITH GREY IRON HOLDING FURNACE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. INTERIOR VIEW, LOOKING WEST, WITH GREY IRON HOLDING FURNACE AND AN IRON POUR IN PROCESS. MOLTEN DUCTILE IRON IS POURED FROM THIS 25-TON HOLDING FURNACE INTO LADLES FOR TRANSPORT TO CASTING STATIONS - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  11. 42. INTERIOR VIEW, LOOKING WEST, WITH GREY IRON HOLDING FURNACE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. INTERIOR VIEW, LOOKING WEST, WITH GREY IRON HOLDING FURNACE AND AN IRON POUR IN PROCESS. MOLTEN DUCTILE IRON IS POURED FROM THIS 25-TON HOLDING FURNACE INTO LADLES FOR TRANSPORT TO CASTING STATIONS - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  12. 7. INTERIOR VIEW, LOOKING WEST, WITH GREY IRON HOLDING FURNACE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. INTERIOR VIEW, LOOKING WEST, WITH GREY IRON HOLDING FURNACE AND AN IRON POUR IN PROCESS. MOLTEN DUCTILE IRON IS POURED FROM THIS 25-TON HOLDING FURNACE INTO LADLES FOR TRANSPORT TO CASTING STATIONS. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  13. 33. BENCH CORE STATION, GREY IRON FOUNDRY CORE ROOM WHERE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. BENCH CORE STATION, GREY IRON FOUNDRY CORE ROOM WHERE CORE MOLDS WERE HAND FILLED AND OFTEN PNEUMATICALLY COMPRESSED WITH A HAND-HELD RAMMER BEFORE THEY WERE BAKED. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  14. On grey levels in random CAPTCHA generation

    NASA Astrophysics Data System (ADS)

    Newton, Fraser; Kouritzin, Michael A.

    2011-06-01

    A CAPTCHA is an automatically generated test designed to distinguish between humans and computer programs; specifically, they are designed to be easy for humans but difficult for computer programs to pass in order to prevent the abuse of resources by automated bots. They are commonly seen guarding webmail registration forms, online auction sites, and preventing brute force attacks on passwords. In the following, we address the question: How does adding a grey level to random CAPTCHA generation affect the utility of the CAPTCHA? We treat the problem of generating the random CAPTCHA as one of random field simulation: An initial state of background noise is evolved over time using Gibbs sampling and an efficient algorithm for generating correlated random variables. This approach has already been found to yield highly-readable yet difficult-to-crack CAPTCHAs. We detail how the requisite parameters for introducing grey levels are estimated and how we generate the random CAPTCHA. The resulting CAPTCHA will be evaluated in terms of human readability as well as its resistance to automated attacks in the forms of character segmentation and optical character recognition.

  15. Free-Standing Canes.

    ERIC Educational Resources Information Center

    Ehresman, Paul

    1995-01-01

    A precane device, called the "free-standing cane," was developed to help children with blindness along with other disabilities. The cane detects obstacles; guides the user's hands into a relaxed, static position in front of the hips; facilitates postural security and control; and offers tactile and kinesthetic feedback. (JDD)

  16. A Diels-Alder super diene breaking benzene into C2H2 and C4H4 units

    NASA Astrophysics Data System (ADS)

    Inagaki, Yusuke; Nakamoto, Masaaki; Sekiguchi, Akira

    2014-01-01

    Cyclic polyene with six carbon atoms (benzene) is very stable, whereas cyclic polyene with four carbon atoms (cyclobutadiene) is extremely unstable. The electron-withdrawing pentafluorophenyl group of a substituted cyclobutadiene lowers the energy of the lowest unoccupied molecular orbital, greatly increasing its reactivity as a diene in Diels-Alder reactions with acetylene, ethylene and even benzene. Here we show that the reaction with benzene occurs cleanly at the relatively low temperature of 120 °C and results in the formal fragmentation of benzene into C2H2 and C4H4 units, via a unique Diels-Alder/retro-Diels-Alder reaction. This is a new example of the rare case where breaking the C-C bond of benzene is possible with no activation by a transition metal.

  17. A Diels–Alder super diene breaking benzene into C2H2 and C4H4 units

    PubMed Central

    Inagaki, Yusuke; Nakamoto, Masaaki; Sekiguchi, Akira

    2014-01-01

    Cyclic polyene with six carbon atoms (benzene) is very stable, whereas cyclic polyene with four carbon atoms (cyclobutadiene) is extremely unstable. The electron-withdrawing pentafluorophenyl group of a substituted cyclobutadiene lowers the energy of the lowest unoccupied molecular orbital, greatly increasing its reactivity as a diene in Diels–Alder reactions with acetylene, ethylene and even benzene. Here we show that the reaction with benzene occurs cleanly at the relatively low temperature of 120 °C and results in the formal fragmentation of benzene into C2H2 and C4H4 units, via a unique Diels–Alder/retro-Diels–Alder reaction. This is a new example of the rare case where breaking the C–C bond of benzene is possible with no activation by a transition metal. PMID:24398593

  18. Total Synthesis of the Galbulimima Alkaloids Himandravine and GB17 Using Biomimetic Diels–Alder Reactions of Double Diene Precursors

    PubMed Central

    Larson, Reed T.; Pemberton, Ryan P.; Franke, Jenna M.; Tantillo, Dean J.; Thomson, Regan J.

    2015-01-01

    The enantioselective total syntheses of himandravine and GB17 were completed through a common biomimetic strategy involving Diels–Alder reactions of unusual double diene containing linear precursors. The double diene precursors, containing or lacking a C12 substituent as required to produce GB17 or himandravine, respectively, were found to undergo Diels–Alder reactions to afford mixtures of regioisomeric cycloadducts that map onto the alternative carbocyclic frameworks of both himandravine and GB17. Computational investigations revealed that these Diels–Alder reactions proceed via transition state structures of similar energy that have a high degree of bispericyclic character and that the low levels of regioselectivity observed in the reactions are a consequence of competing orbital interaction and distortion energies. The combined experimental and computational results provide valuable insights into the biosynthesis of the Galbulimima alkaloids. PMID:26305231

  19. Regiocontrol by remote substituents. An enantioselective total synthesis of frenolicin B via a highly regioselective Diels-Alder reaction

    SciTech Connect

    Kraus, G.A.; Li, J. ); Gordon, M.S.; Jensen, J.H. )

    1993-06-30

    The quinone subunit is contained in a broad range of biologically important natural products such as frenolicin B, which is a member of the pyranonaphthoquinone family. The diverse biological activity of quinones has led to the development of several new synthetic methods for quinones. Among the pathways featuring a cycloaddition reaction, one of the most general methods for the regiospecific synthesis of substituted quinones was pioneered by H.J. Rapoport and others. This method involves the Diels-Alder reaction of a substituted quinone. As part of a program to evaluate the directing effects of functional groups not directly attached to the atoms undergoing Diels-Alder cycloaddition, we now report that remote substituents on a dienophile can confer excellent regioselectivity in Diels-Alder reactions. This work has led to an extremely direct synthesis of the pyranonaphthoquinone framework and to the first synthesis of frenolicin B (1). 19 refs., 1 fig.

  20. Aqueous catalysis: Methylrhenium trioxide (MTO) as a homogeneous catalyst for the Diels-Alder reaction

    SciTech Connect

    Zhu, Z.; Espenson, J.H.

    1997-04-16

    The title compound proves to be an effective and efficient catalyst for the Diels-Alder reaction when the dienophile is an {alpha},{beta}-unsaturated ketone or aldehyde. It is especially effective in water. Equal amounts of any such dienophile and any of six representative dienes (isoprene, 2-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, cyclopentadiene, 1,2,3,4,5,-pentamethylcyclopentadiene, and 1,3-cyclohexadiene) were used, along with 1% MTO. The reactions gave usually > 90% isolated yield of the cycloaddition product except for the larger dienophiles. Nearly exclusively, there was formed one product isomer, the same one that usually predominates. The reactions were often run in chloroform (mostly) and in other organic solvents. A select number were carried out in water, where the reactions gave a greater product yield in a considerably shorter time. Water, itself, is known to enhance the rates of Diels-Alder reactions, but MTO exerts an additional accelerating effect. Kinetics studies were carried out to show that the rate is proportional to the catalyst concentration. The products do not inhibit the reaction. The desirability of MTO as a Diels-Alder catalyst stems from a combination of favorable properties: the inertness to air/oxygen, the tolerance for many substrates, the use of an aqueous medium, and the absence of product inhibition. The initial step appears to be the (weak) coordination of the carbonyl oxygen to the electropositive rhenium center. Steric crowding around rhenium inhibits reactions of the larger dienophiles. 26 refs., 3 figs., 4 tabs.

  1. Insight on mendable resin made by combining Diels-Alder epoxy adducts with DGEBA

    NASA Astrophysics Data System (ADS)

    Dello Iacono, S.; Martone, A.; Filippone, G.; Acierno, D.; Zarrelli, M.; Giordano, M.; Amendola, E.

    2016-05-01

    Formation of micro-cracks is a critical problem in polymers and polymer composites during their service in structural applications. In this context, materials endowed with self-healing features would lead to the next polymers generation. In the present paper, an epoxy system integrating Diels-Alder epoxy adducts is investigated by thermal and spectroscopic analysis. The direct and retro D-A reaction have been studied by FTIR and specific absorption bands have been identified. Finally, mechanical tests have been performed on the system. The polymer is able to heal fracture and micro-cracks recovering its stiffness after a thermal treatment.

  2. Asymmetric Syntheses of the Flavonoid Diels–Alder Natural Products Sanggenons C and O

    PubMed Central

    Qi, Chao; Xiong, Yuan; Eschenbrenner-Lux, Vincent; Cong, Huan

    2016-01-01

    Metal-catalyzed, double Claisen rearrangement of a bis-allyloxyflavone has been utilized to enable a concise synthesis of the hydrobenzofuro[3,2-b]chromenone core structure of the natural products sanggenon A and sanggenol F. In addition, catalytic, enantioselective [4+2] cycloadditions of 2′-hydroxychalcones have been accomplished using B(OPh)3/BINOL complexes. Asymmetric syntheses of the flavonoid Diels–Alder natural products sanggenons C and O have been achieved employing a stereodivergent reaction of a racemic mixture (stereodivergent RRM) involving [4+2] cycloaddition. PMID:26735066

  3. Mechanistic insights into the stepwise Diels-Alder reaction of 4,6-dinitrobenzofuroxan.

    PubMed

    Linder, Mats; Johansson, Adam Johannes; Brinck, Tore

    2012-01-06

    The stepwise Diels-Alder reaction between 1-trimethylsiloxy-1,3-butadiene and 4,6-dinitrobenzofuroxan is explored using state-of-the-art computational methods. The results support a stepwise mechanism via a persistent intermediate, however, not the one previously reported (Lakhdar et al., Chem. Eur. J.2007, 16, 5681) but a heterocyclic adduct. The novel DFT functional M062X and the SCS-MP2 method were essential to reproduce a reasonable potential energy surface for this challenging system.

  4. 1-Azadienes as regio- and chemoselective dienophiles in aminocatalytic asymmetric Diels-Alder reaction.

    PubMed

    Ma, Chao; Gu, Jing; Teng, Bin; Zhou, Qing-Qing; Li, Rui; Chen, Ying-Chun

    2013-12-20

    Electron-deficient 1-aza-1,3-butadienes containing a 1,2-benzoisothiazole-1,1-dioxide or 1,2,3-benzoxathiazine-2,2-dioxide motif act as regio- and chemoselective dienophiles in normal-electron-demand Diels-Alder reactions with HOMO-raised trienamines, rather than typical 4π-participation in inverse-electron-demand versions. The enantioenriched cycloadducts could be efficiently converted to spiro or fused frameworks with high structural and stereogenic complexity by a sequential aza-benzoin reaction or other transformations.

  5. Structural Modification of Sol-Gel Materials through Retro Diels-Alder Reaction

    SciTech Connect

    SHALTOUT,RAAFAT M.; LOY,DOUGLAS A.; MCCLAIN,MARK D.; PRABAKAR,SHESHASAYANA; GREAVES,JOHN; SHEA,KENNETH J.

    1999-12-08

    Hydrolysis and condensation of organically bridged bis-triethoxysilanes, (EtO){sub 3}Si-R-Si(OEt){sub 3}, results in the formation of three dimensional organic/inorganic hybrid networks (Equation 1). Properties of these materials, including porosity, are dependent on the nature of the bridging group, R. Flexible groups (akylene-spacers longer than five carbons in length) polymerize under acidic conditions to give non-porous materials. Rigid groups (such as arylene-, alkynylene-, or alkenylene) form non-porous, microporous, and macroporous gels. In many cases the pore size distributions are quite narrow. One of the motivations for preparing hybrid organic-inorganic materials is to extend the range of properties available with sol-gel systems by incorporating organic groups into the inorganic network. For example, organically modified silica gels arc either prepared by co-polymerizing an organoalkoxysilane with a silica precursor or surface silylating the inorganic gel. This can serve to increase hydrophobicity or to introduce some reactive organic functionality. However, the type and orientation of these organic functionalities is difficult to control. Furthermore, many organoalkoxysilanes can act to inhibitor even prevent gelation, limiting the final density of organic functionalities. We have devised a new route for preparing highly functionalized pores in hybrid materials using bridging groups that are thermally converted into the desired functionalities after the gel has been obtained. In this paper, we present the preparation and characterization of bridged polysilsesquioxanes with Diels-Alder adducts as the bridging groups from the sol-gel polymerization of monomers 2 and 4. The bridging groups are constructed such that the retro Diela-Alder reaction releases the dienes and leaves the dienophiles as integral parts of the network polymers. In the rigid architecture of a xerogel, this loss of organic functionality should liberate sufficient space to modify the

  6. Diels-Alder cycloadditions in water for the straightforward preparation of peptide–oligonucleotide conjugates

    PubMed Central

    Marchán, Vicente; Ortega, Samuel; Pulido, Daniel; Pedroso, Enrique; Grandas, Anna

    2006-01-01

    The Diels-Alder reaction between diene-modified oligonucleotides and maleimide-derivatized peptides afforded peptide–oligonucleotide conjugates with high purity and yield. Synthesis of the reagents was easily accomplished by on-column derivatization of the corresponding peptides and oligonucleotides. The cycloaddition reaction was carried out in mild conditions, in aqueous solution at 37°C. The speed of the reaction was found to vary depending on the size of the reagents, but it can be completed in 8–10 h by reacting the diene-oligonucleotide with a small excess of maleimide-peptide. PMID:16478710

  7. Diels-Alder reactions of five-membered heterocycles containing one heteroatom.

    PubMed

    Ding, Xiaoyuan; Nguyen, Son T; Williams, John D; Peet, Norton P

    2014-12-17

    Diels-Alder reactions of five-membered heterocycles containing one heteroatom with an N-arylmaleimide were studied. Cycloaddition of 2,5-dimethylfuran (4) with 2-(4-methylphenyl)maleimide (3) in toluene at 60 °C gave bicyclic adduct 5. Cycloadditions of 3 with 2,5-dimethylthiophene (11) and 1,2,5-trimethylpyrrole (14) were also studied. Interestingly, the bicyclic compound 5 cleanly rearranged, with loss of water, when treated with p-toluenesulfonic acid in toluene at 80 °C to give 4,7-dimethyl-2-p-tolylisoindoline-1,3-dione (6).

  8. Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

    PubMed Central

    Miller, Marvin J

    2016-01-01

    Summary The hetero-Diels–Alder reaction between a nitroso dienophile and a conjugated diene to give the 3,6-dihydro-2H-1,2-oxazine scaffold is useful for the synthesis of many biologically interesting molecules due to the diverse opportunities created by subsequent transformations of the resulting 1,2-oxazine ring. This review discusses the rationale for the observed regio- and stereoselectivity and the methods developed in recent years used to control and improve the stereo- and regioselectivity for the synthesis of 1,2-oxazine scaffolds. PMID:27829901

  9. Highly enantioselective access to cannabinoid-type tricyles by organocatalytic Diels–Alder reactions

    PubMed Central

    Volz, Nicole; Gläser, Franziska; Nieger, Martin

    2012-01-01

    Summary After prosperous domino reactions towards benzopyrans, the products were used as the starting material in Lewis acid catalyzed and organocatalytic Diels–Alder reactions to build up a tricyclic system. Herein, an asymmetric induction up to 96% enantiomeric excess was obtained by the use of imidazolidinone catalysts. This approach can be utilized to construct the tricyclic system in numerous natural products, in particular the scaffold of tetrahydrocannabinol (THC) being the most representative one. Compared with other published methods, condensation with a preexisting cyclohexane moiety in the precursor is needed to gain the heterogenic tricycle systems, whereas we present a novel strategy towards cannabinoid derivatives based on a flexible modular synthesis. PMID:23019475

  10. Highly enantioselective access to cannabinoid-type tricyles by organocatalytic Diels-Alder reactions.

    PubMed

    Bräse, Stefan; Volz, Nicole; Gläser, Franziska; Nieger, Martin

    2012-01-01

    After prosperous domino reactions towards benzopyrans, the products were used as the starting material in Lewis acid catalyzed and organocatalytic Diels-Alder reactions to build up a tricyclic system. Herein, an asymmetric induction up to 96% enantiomeric excess was obtained by the use of imidazolidinone catalysts. This approach can be utilized to construct the tricyclic system in numerous natural products, in particular the scaffold of tetrahydrocannabinol (THC) being the most representative one. Compared with other published methods, condensation with a preexisting cyclohexane moiety in the precursor is needed to gain the heterogenic tricycle systems, whereas we present a novel strategy towards cannabinoid derivatives based on a flexible modular synthesis.

  11. Thiourea-catalyzed Diels-Alder reaction of a naphthoquinone monoketal dienophile.

    PubMed

    Kramer, Carsten S; Bräse, Stefan

    2013-01-01

    A variety of organocatalysts were screened for the catalysis of the naphthoquinone monoketal Diels-Alder reaction. In this study we found that Schreiner's thiourea catalyst 10 and Jacobson's thiourea catalyst 12 facilitate the cycloaddition of the sterically hindered naphthoquinone monoketal dienophile 3 with diene 4. The use of thiourea catalysis allowed for the first time the highly selective synthesis of the exo-product 2a in up to 63% yield. In this reaction a new quaternary center was built. The so formed cycloaddition product 2a represents the ABC tricycle of beticolin 0 (1) and is also a valuable model substrate for the total synthesis of related natural products.

  12. Color and Grey Scale in Sonar Displays

    NASA Technical Reports Server (NTRS)

    Kraiss, K. F.; Kuettelwesch, K. H.

    1984-01-01

    In spite of numerous publications 1 it is still rather unclear, whether color is of any help in sonar displays. The work presented here deals with a particular type of sonar data, i.e., LOFAR-grams (low frequency analysing and recording) where acoustic sensor data are continuously written as a time-frequency plot. The question to be answered quantitatively is, whether color coding does improve target detection when compared with a grey scale code. The data show significant differences in receiver-operating characteristics performance for the selected codes. In addition it turned out, that the background noise level affects the performance dramatically for some color codes, while others remain stable or even improve. Generally valid rules are presented on how to generate useful color scales for this particular application.

  13. 20. Building 202, detail of stand A, rocket test stand ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. Building 202, detail of stand A, rocket test stand in test cell. View looking southeast. - Rocket Engine Testing Facility, GRC Building No. 202, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

  14. Microbiological quality of grey-mullet roe.

    PubMed

    Voidarou, C; Alexopoulos, A; Plessas, S; Noussias, H; Stavropoulou, E; Fotou, K; Tzora, A; Skoufos, I; Bezirtzoglou, E; Demertzi-Akrida, K

    2011-12-01

    The Greek grey-mullet roe is produced from the fully developed gonads of the female mullet (Mugil cephalus) couth in lagoons during their reproductive migration. The traditional processing method of the roe includes, air drying, salting, shape formation and covering with multiple layers of natural beeswax for preservation and distribution. Fish Roe brands have been a staple in local diet and is increasingly becoming popular in the international market. As a ready-to-eat food it's microbial quality should be of concern for the protection of consumers health. In this study, 48 samples of fish roe, just before waxing, were collected from various local processors for microbiological examination by using selective media and incubated under aerobic and anaerobic conditions. The identification of the bacteria was carried out according to the Bergey's manual. Microscopic examination of Gram stained cells, catalase, oxidase and biochemical tests were performed when necessary to further identify. V. parahaemolyticus, Vibrio spp., Salmonella spp., and Aeromonas hydrophila were detected in one sample (2%). Shigella spp., and Flavobacterium spp. in two samples (4%), Clotriduim perfringens (vegetative forms), E. coli, and spores of Bacillus spp., were detected in three samples (6%), Staphylococcus aureus in four samples (8%). Various Micrococcus spp., and spores of C. perfringens in 16% and 35% of the samples respectively. From the Listeria genus, only the species Listeria innocua, Listeria welshimeri, Listeria seeligeri Listeria ivanovii and Listeria grayi were recovered from 2 to 10% of the samples. Microbiological analyses revealed the presence of a small number of pathogens in grey-mullet roe samples which are in accordance with the findings of similar studies. Traditional processing of the fish roe, seems inadequate to ensure the food safety and even waxing isn't expected to fully protect them against facultative anaerobes with salt tolerance. Therefore, additional measures

  15. Using atmospheric pressure plasma treatment for treating grey cotton fabric.

    PubMed

    Kan, Chi-Wai; Lam, Chui-Fung; Chan, Chee-Kooi; Ng, Sun-Pui

    2014-02-15

    Conventional wet treatment, desizing, scouring and bleaching, for grey cotton fabric involves the use of high water, chemical and energy consumption which may not be considered as a clean process. This study aims to investigate the efficiency of the atmospheric pressure plasma (APP) treatment on treating grey cotton fabric when compared with the conventional wet treatment. Grey cotton fabrics were treated with different combinations of plasma parameters with helium and oxygen gases and also through conventional desizing, scouring and bleaching processes in order to obtain comparable results. The results obtained from wicking and water drop tests showed that wettability of grey cotton fabrics was greatly improved after plasma treatment and yielded better results than conventional desizing and scouring. The weight reduction of plasma treated grey cotton fabrics revealed that plasma treatment can help remove sizing materials and impurities. Chemical and morphological changes in plasma treated samples were analysed by FTIR and SEM, respectively. Finally, dyeability of the plasma treated and conventional wet treated grey cotton fabrics was compared and the results showed that similar dyeing results were obtained. This can prove that plasma treatment would be another choice for treating grey cotton fabrics.

  16. Get up, Stand up

    ERIC Educational Resources Information Center

    Melia, Ed

    2009-01-01

    Ignorance about dyslexia meant a miserable school experience for Barrie Hughes. He was in his 50s when he found the courage to stand up in front of a classroom of learners and admit he couldn't read. Barrie, who is now 59 and works for the parks department of Brighton and Hove Council, only began to learn how to read words in the last three years…

  17. Beam optics test stand

    NASA Astrophysics Data System (ADS)

    Humphries, S., Jr.; Hess, G.

    1988-04-01

    The design and construction of the Beam Optics Test Stand (BOTS) is presented. A variety of computer compatible diagnostics has been developed to facilitate experiments. Extensive theoretical work is presented leading to the identification of two potential methods to correct aberrations in magnetic optics: biased grid arrays and space charge corrected solenoidal lenses. A series of experiments is presented which demonstrates, for the first time, the feasibility of space charge corrected optics.

  18. Phagocytosis in pup and adult harbour, grey and harp seals.

    PubMed

    Frouin, Héloïse; Lebeuf, Michel; Hammill, Mike; Fournier, Michel

    2010-04-15

    Knowledge on pinniped immunology is still in its infancy. For instance, age-related and developmental aspects of the immune system in pinnipeds need to be better described. The present study examined the phagocytic activity and efficiency of harbour, grey and harp seal leukocytes. In the first part of the study, peripheral blood was collected from captive female harbour seals of various ages. Data showed an age-related decrease in phagocytosis in female harbour seals from sub-adult to adulthood. In the second part of the study, changes in phagocytosis were quantified during lactation in wild newborn harbour, grey and harp seals and in their mothers (harp and grey seals). In newborns of the same age, leukocytes of harbour and harp seals phagocytosed less than those of grey seal pups. The phagocytic activity and efficiency increased significantly from early to mid-lactation in newborn harbour seals, and from early to late lactation in newborn grey seals, which could suggest that the transfer of phagocytosis-promoting factor(s) in colostrum is an important feature of temporary protection for pups. In contrast, no changes in phagocytic activity and efficiency were observed in lactating females of the two seal species, harp and grey, examined. At late lactation, phagocytic activity in both grey and harp seal pups and phagocytic efficiency in grey seal pups were significantly higher than in their mothers. These results could reflect either the capacity of phagocytes of the newborn harp and grey seals to respond to pathogens. Results from this study suggest that the phagocytosis of the seal species examined is not fully developed at birth as it generally increases in pups during lactation. Thereafter, the phagocytic activity of seals appears to decrease throughout adulthood.

  19. Bibliometric study of grey literature in core veterinary medical journals

    PubMed Central

    Pelzer, Nancy L.; Wiese, William H.

    2003-01-01

    Objectives: Grey literature has been perceived by many as belonging to the primary sources of information and has become an accepted method of nonconventional communication in the sciences and medicine. Since little is known about the use and nature of grey literature in veterinary medicine, a systematic study was done to analyze and characterize the bibliographic citations appearing in twelve core veterinary journals. Methods: Citations from 2,159 articles published in twelve core veterinary journals in 2000 were analyzed to determine the portion of citations from grey literature. Those citations were further analyzed and categorized according to the type of publication. Results: Citation analysis yielded 55,823 citations, of which 3,564 (6.38%) were considered to be grey literature. Four veterinary specialties, internal medicine, pathology, theriogenology, and microbiology, accounted for 70% of the total number of articles. Three small-animal clinical practice journals cited about 2.5–3% grey literature, less than half that of journals with basic research orientations, where results ranged from almost 6% to approximately 10% grey literature. Nearly 90% of the grey literature appeared as conferences, government publications, and corporate organization literature. Conclusions: The results corroborate other reported research that the incidence of grey literature is lower in medicine and biology than in some other fields, such as aeronautics and agriculture. As in other fields, use of the Internet and the Web has greatly expanded the communication process among veterinary professionals. The appearance of closed community email forums and specialized discussion groups within the veterinary profession is an example of what could become a new kind of grey literature. PMID:14566374

  20. Ecology and behaviour of the Alder Flycatcher Empidonax alnorum, Tyrannidae in winter

    USGS Publications Warehouse

    Foster, M.; Adams, N.J.; Slotow, R.H.

    1999-01-01

    The Alder Flycatcher Empidonax alnorum (Tyrannidae) winters from Colombia and Venezuela, south to northern Argentina. We studied the species in Manu National Park, Madre de Dios, Peru. In this area the species occupies riparian zones along lowland meander rivers as well as adjacent transition zone forest in the floodplain. These habitats have a number of age-related longitudinal zones (parallel to the river margin) that are short term (I-2 year) transitory stages in the succession to floodplain forest. The fast growing plant species that make up these habitats are suitable for commercial harvest for paper pulp. We examined habitat use of the species in an attempt to identify the effects of such harvest and resulting habitat loss on these birds. The Alder Flycatcher favours two longitudinal zones where it establishes territories. The territories may be long-term or transitory, and are often occupied and defended by two individuals, generally of different age. One bird tends to be more active in territory defence than the other. Defence involves patrolling, vocal duels, and chases. Birds sally for insects but also eat large quantities of fruit.

  1. Ecology and behaviour of the Alder Flycatcher Empidonax alnorum, Tyrannidae in winter

    USGS Publications Warehouse

    Foster, M.; Adams, N.J.; Slotow, R.H.

    1998-01-01

    The Alder Flycatcher Empidonax alnorum (Tyrannidae) winters from Colombia and Venezuela, south to northern Argentina. We studied the species in Manu National Park, Madre de Dios, Peru. In this area the species occupies riparian zones along lowland meander rivers as well as adjacent transition zone forest in the floodplain. These habitats have a number of age-related longitudinal zones (parallel to the river margin) that are short term (I-2 year) transitory stages in the succession to floodplain forest. The fast growing plant species that make up these habitats are suitable for commercial harvest for paper pulp. We examined habitat use of the species in an attempt to identify the effects of such harvest and resulting habitat loss on these birds. The Alder Flycatcher favours two longitudinal zones where it establishes territories. The territories may be long-term or transitory, and are often occupied and defended by two individuals, generally of different age. One bird tends to be more active in territory defence than the other. Defence involves patrolling, vocal duels, and chases. Birds sally for insects but also eat large quantities of fruit.

  2. New Insights into the Diels-Alder Reaction of Graphene Oxide.

    PubMed

    Brisebois, Patrick P; Kuss, Christian; Schougaard, Steen B; Izquierdo, Ricardo; Siaj, Mohamed

    2016-04-18

    Graphene oxide is regarded as a major precursor for graphene-based materials. The development of graphene oxide based derivatives with new functionalities requires a thorough understanding of its chemical reactivity, especially for canonical synthetic methods such as the Diels-Alder cycloaddition. The Diels-Alder reaction has been successfully extended with graphene oxide as a source of diene by using maleic anhydride as a dienophile, thereby outlining the presence of the cis diene present in the graphene oxide framework. This reaction provides fundamental information for understanding the exact structure and chemical nature of graphene oxide. On the basis of high-resolution (13) C-SS NMR spectra, we show evidence for the formation of new sp(3) carbon centers covalently bonded to graphene oxide following hydrolysis of the reaction product. DFT calculations are also used to show that the presence of a cis dihydroxyl and C vacancy on the surface of graphene oxide are promoting the reaction with significant negative reaction enthalpies.

  3. Diels-Alder reactions of 4-halo masked o-benzoquinones. Experimental and theoretical investigations.

    PubMed

    Surasani, Seshi Reddy; Parumala, Santosh Kumar Reddy; Peddinti, Rama Krishna

    2014-08-14

    The studies on [4 + 2] cycloaddition of 4-halo derivatives of 6,6-dimethoxycyclohexa-2,4-dienones known as orthoquinone monoketals/masked o-benzoquinones are described. The 4-fluoro, 4-chloro- and 4-iodo-masked o-benzoquinones were stable enough for their isolation and characterization. These conjugated dienones cycloadded with several electron-deficient and electron-rich dienophiles in a highly regio- and stereo-selective manner to afford the corresponding halo bicyclo[2.2.2]octenone derivatives in high to excellent chemical yields. The halo masked o-benzoquinones did not undergo dimerization under the reaction conditions. To evaluate the observed selectivities of these Diels-Alder reactions, we have performed quantum mechanical calculations for the reactions between halo masked o-benzoquinones and methyl vinyl ketone and ethyl vinyl ether at the B3LYP/6-31G** theory level. The differences in HOMO and LUMO energy gaps suggest that these reactions can be classified as inverse electron-demand Diels-Alder reactions. The calculated transition state energies and global electronic indexes supported the experimentally observed selectivities of the reaction in many cases.

  4. Alternative statistical methods for interpreting airborne Alder ( Alnus glutimosa (L.) Gaertner) pollen concentrations

    NASA Astrophysics Data System (ADS)

    González Parrado, Zulima; Valencia Barrera, Rosa M.; Fuertes Rodríguez, Carmen R.; Vega Maray, Ana M.; Pérez Romero, Rafael; Fraile, Roberto; Fernández González, Delia

    2009-01-01

    This paper reports on the behaviour of Alnus glutinosa (alder) pollen grains in the atmosphere of Ponferrada (León, NW Spain) from 1995 to 2006. The study, which sought to determine the effects of various weather-related parameters on Alnus pollen counts, was performed using a volumetric method. The main pollination period for this taxon is January-February. Alder pollen is one of the eight major airborne pollen allergens found in the study area. An analysis was made of the correlation between pollen counts and major weather-related parameters over each period. In general, the strongest positive correlation was with temperature, particularly maximum temperature. During each period, peak pollen counts occurred when the maximum temperature fell within the range 9°C-14°C. Finally, multivariate analysis showed that the parameter exerting the greatest influence was temperature, a finding confirmed by Spearman correlation tests. Principal components analysis suggested that periods with high pollen counts were characterised by high maximum temperature, low rainfall and an absolute humidity of around 6 g m-3. Use of this type of analysis in conjunction with other methods is essential for obtaining an accurate record of pollen-count variations over a given period.

  5. Liquid phase thermochemical energy conversion systems - An application of Diels-Alder chemistry

    NASA Astrophysics Data System (ADS)

    Lenz, T. G.; Hegedus, L. S.; Vaughan, J. D.

    1982-12-01

    A method of thermochemical energy conversion, transport, and storage research involving moderate and low temperature liquid phase systems employing Diels-Alder cycloaddition chemistry is described. Proposed as a heat storage system for solar and industrial waste heat, the system involves the meeting, in a reactor, of energy-depleted and energy-rich fluids. The poor fluid gains energy and goes through a chemical, endothermic dissociative change. The use of Diels-Alder reactions provides completely reversible chemical reactions for this application. The heated fluid can be retransported for storage or implementation as a heat source. The return reaction, releasing the stored heat, can be done spontaneously or in the presence of a catalyst such as Lewis acids. Attention is recommended for the Wentworth-Chen temperature of 250-300 C to minimize the system thermal degradation. Research in the synthesis of diene and dienophile candidate chemicals, into sealed tube and reaction kinetic techniques, and into NMR techniques for identifying further reaction candidates are discussed.

  6. Stepwise Diels-Alder: more than just an oddity? A computational mechanistic study.

    PubMed

    Linder, Mats; Brinck, Tore

    2012-08-03

    We have employed hybrid DFT and SCS-MP2 calculations at the SMD-PCM-6-311++G(2d,2p)//6-31+G(d) level to investigate the relationship between three possible channels for forming a Diels-Alder adduct from a highly nucleophilic diene and moderately to highly electrophilic dienophiles. We discuss geometries optimized using the B3LYP and M06-2X functionals with the 6-31+(d) basis set. The transition states and intermediates are characterized on the basis of geometric and electronic properties, and we also address the possibility of predicting detectability of a zwitterionic intermediate based on its relative stability. Our results show that a conventional Diels-Alder transition state conformation yields intermediates in all four investigated cases, but that these are too short-lived to be detected experimentally for the less activated reactants. The stepwise trans pathway, beginning with a conjugate addition-like transition state, becomes increasingly competitive with more activated reactants and is indeed favored for the most electrophilic dienophiles. Addition of a trans diene leads to a dead-end as the trans intermediates have insurmountable rotation barriers that prohibit formation of the second bond, unless another, heterocyclic intermediate is formed. We also show that introduction of a hydrogen bond donating catalyst favors a stepwise pathway even for less activated dienophiles.

  7. Reconfigurable biodegradable shape-memory elastomers via Diels-Alder coupling.

    PubMed

    Ninh, Chi; Bettinger, Christopher J

    2013-07-08

    Synthetic biodegradable elastomers are a class of polymers that have demonstrated far-reaching utility as biomaterials for use in many medical applications. Biodegradable elastomers can be broadly classified into networks prepared by either step-growth or chain-growth polymerization. Each processing strategy affords distinct advantages in terms of capabilities and resulting properties of the network. This work describes the synthesis, processing, and characterization of cross-linked polyester networks based on Diels-Alder coupling reactions. Hyperbranched furan-modified polyester precursors based on poly(glycerol-co-sebacate) are coupled with bifunctional maleimide cross-linking agents. The chemical and thermomechanical properties of the elastomers are characterized at various stages of network formation. Experimental observations of gel formation are compared to theoretical predictions derived from Flory-Stockmayer relationships. This cross-linking strategy confers unique advantages in processing and properties including the ability to fabricate biodegradable reconfigurable covalent networks without additional catalysts or reaction byproducts. Reconfigurable biodegradable networks using Diels-Alder cycloaddition reactions permit the fabrication of shape-memory polymers with complex permanent geometries. Biodegradable elastomers based on polyester networks with molecular reconfigurability achieve vastly expanded properties and processing capabilities for potential applications in medicine and beyond.

  8. Unconventional exo selectivity in thermal normal-electron-demand Diels–Alder reactions

    PubMed Central

    Ho, Guo-Ming; Huang, Ci-Jhang; Li, Elise Yu-Tzu; Hsu, Sheng-Kai; Wu, Ti; Zulueta, Medel Manuel L.; Wu, Kevin Binchia; Hung, Shang-Cheng

    2016-01-01

    The Diels–Alder reaction is a useful tool for generating functionalized chiral molecules through the concerted cycloaddition of dienes and dienophiles leading to six-membered rings. Traditionally, the selective predictions of the products rely heavily on consideration of the secondary orbital interactions that stabilize the endo pathway. However, there remain some basic examples defying this notion and produce the exo-isomer as major product. Here we systematically evaluated of the structural features driving exo selectivity in thermal normal-electron-demand Diels–Alder reactions. Substitution at the Cβ position and the size and electronegativity of the electron-withdrawing group of the dienophile are contributing factors. Experimental and computational studies both point toward the steric and electrostatic forces between the substituents in both the diene and the dienophile that increase the likelihood of the exo pathway. For these substrates, the dominance of the endo pathway is reduced by transition state distortions and poor structural alignments of the reacting partners. We also noted the tilt of the dienophile with respect to the diene causing steric strain on the functionalities at the more advanced bond forming carbon-carbon position of the endo transition state. Insights into such factors may benefit synthetic planning and asserting control over this important named reaction. PMID:27731360

  9. Unconventional exo selectivity in thermal normal-electron-demand Diels–Alder reactions

    NASA Astrophysics Data System (ADS)

    Ho, Guo-Ming; Huang, Ci-Jhang; Li, Elise Yu-Tzu; Hsu, Sheng-Kai; Wu, Ti; Zulueta, Medel Manuel L.; Wu, Kevin Binchia; Hung, Shang-Cheng

    2016-10-01

    The Diels–Alder reaction is a useful tool for generating functionalized chiral molecules through the concerted cycloaddition of dienes and dienophiles leading to six-membered rings. Traditionally, the selective predictions of the products rely heavily on consideration of the secondary orbital interactions that stabilize the endo pathway. However, there remain some basic examples defying this notion and produce the exo-isomer as major product. Here we systematically evaluated of the structural features driving exo selectivity in thermal normal-electron-demand Diels–Alder reactions. Substitution at the Cβ position and the size and electronegativity of the electron-withdrawing group of the dienophile are contributing factors. Experimental and computational studies both point toward the steric and electrostatic forces between the substituents in both the diene and the dienophile that increase the likelihood of the exo pathway. For these substrates, the dominance of the endo pathway is reduced by transition state distortions and poor structural alignments of the reacting partners. We also noted the tilt of the dienophile with respect to the diene causing steric strain on the functionalities at the more advanced bond forming carbon-carbon position of the endo transition state. Insights into such factors may benefit synthetic planning and asserting control over this important named reaction.

  10. Microwave-Enhanced Organic Syntheses for the Undergraduate Laboratory: Diels-Alder Cycloaddition, Wittig Reaction, and Williamson Ether Synthesis

    ERIC Educational Resources Information Center

    Baar, Marsha R.; Falcone, Danielle; Gordon, Christopher

    2010-01-01

    Microwave heating enhanced the rate of three reactions typically performed in our undergraduate organic chemistry laboratory: a Diels-Alder cycloaddition, a Wittig salt formation, and a Williamson ether synthesis. Ninety-minute refluxes were shortened to 10 min using a laboratory-grade microwave oven. In addition, yields improved for the Wittig…

  11. Investigation of the possibility of functionalization of C20 fullerene by benzene via Diels-Alder reaction

    NASA Astrophysics Data System (ADS)

    Siadati, Seyyed Amir; Nami, Navabeh

    2016-10-01

    C20 fullerene, this novel species with all its pentagonal faces has displayed some unique operations in making fast pericyclic reactions. As an example, the high dienophile character of the C20 fullerene and the ability of this species in making an ultra-fast Diels-Alder reaction with 1,3-butadiene, has been recently reported. Moreover, new experimental reports claim that the C60 fullerene, one of the fullerene family, could make a Diels-Alder reaction with the central ring of anthracene and make the ring non-aromatic. These reports may encourage researchers to do more studies on the properties of this small carbon cage. To address this question, the present research has discussed all the reaction channels of the Diels-Alder cycloaddition of benzene molecule as a 1,3-diene with the C20 fullerene in order to answer this question: "Is C20fullerene able to make a Diels-Alder reaction with this molecule?".

  12. Sorocenols G and H, Anti-MRSA Oxygen Heterocyclic Diels-Alder-type Adducts from Sorocea muriculata Roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioassay-guided fractionation of a root extract of Sorocea muriculata led to the isolation and identification of two new oxygen heterocyclic Diels-Alder-type adducts, sorocenols G (1) and H (2), along with lupeol-3-(3'R-hydroxytetradecanoate) and oxyresveratrol. The structures of 1 and 2 were eluci...

  13. NITROGEN EXPORT FROM FORESTED WATERSHEDS IN THE OREGON COAST RANGE: THE ROLE OF N2-FIXING RED ALDER

    EPA Science Inventory

    Variations in plant community composition across the landscape can influence nutrient retention and loss at the watershed scale. A striking example of plant species influence is the role of N2-fixing red alder (Alnus rubra) in the biogeochemistry of Pacific Northwest forests. T...

  14. Organocatalytic sequential hetero-Diels-Alder and Friedel-Crafts reaction: constructions of fused heterocycles with scaffold diversity.

    PubMed

    Zhou, Si-Li; Li, Jun-Long; Dong, Lin; Chen, Ying-Chun

    2011-11-04

    A highly enantioselective aza-Diels-Alder and Friedel-Crafts reaction sequence of N-sulfonyl-1-aza-1,3-butadienes and aliphatic aldehydes tethered to an arene motif has been developed, affording the fused chiral piperidine frameworks with a versatile scaffold diversity. A similar strategy has been applied for the construction of complex chiral tetrahydroquinoxaline structures.

  15. A Counterion‐Directed Approach to the Diels–Alder Paradigm: Cascade Synthesis of Tricyclic Fused Cyclopropanes

    PubMed Central

    Kiss, Emily; Campbell, Craig D.; Driver, Russell W.; Jolliffe, John D.; Lang, Rosemary; Sergeieva, Tetiana; Okovytyy, Sergiy

    2016-01-01

    Abstract An approach to the intramolecular Diels–Alder reaction has led to a cascade synthesis of complex carbocycles composed of three fused rings and up to five stereocenters with complete stereocontrol. Computational analysis reveals that the reaction proceeds by a Michael/Michael/cyclopropanation/epimerization cascade in which size and coordination of the counterion is key. PMID:27714921

  16. A 11-Steps Total Synthesis of Magellanine through a Gold(I)-Catalyzed Dehydro Diels-Alder Reaction.

    PubMed

    McGee, Philippe; Bétournay, Geneviève; Barabé, Francis; Barriault, Louis

    2017-01-12

    We have developed an innovative strategy for the formation of angular carbocycles via a gold(I)-catalyzed dehydro Diels-Alder reaction. This transformation provides rapid access to a variety of complex angular cores in excellent diastereoselectivities and high yields. The usefulness of this Au(I) -catalyzed cycloaddition was further demonstrated by accomplishing a 11-steps total synthesis of (±)-magellanine.

  17. Biosynthesis inspired Diels-Alder route to pyridines: synthesis of the 2,3-dithiazolylpyridine core of the thiopeptide antibiotics.

    PubMed

    Moody, Christopher J; Hughes, Rachael A; Thompson, Stewart P; Alcaraz, Lilian

    2002-08-21

    Reaction of serine derived 1-alkoxy-2-azadienes with dehydroalanine derived dienophiles results in Diels-Alder reaction and aromatisation to give 2,3,6-trisubstituted pyridines, thereby establishing the viability of the proposed biosynthetic route to the pyridine ring of the thiopeptide antibiotics originally proposed by Bycroft and Gowland.

  18. Silver-Catalyzed Formal Inverse Electron-Demand Diels-Alder Reaction of 1,2-Diazines and Siloxy Alkynes

    PubMed Central

    Türkmen, Yunus E.; Montavon, Timothy J.; Kozmin, Sergey A.; Rawal, Viresh H.

    2012-01-01

    A highly effective silver-catalyzed formal inverse electron-demand Diels-Alder reaction of 1,2-diazines and siloxy alkynes has been developed. The reactions provide ready access to a wide range of siloxy naphthalenes and anthracenes, which are formed in good to high yields, under mild reaction conditions, using low catalyst loadings. PMID:22607029

  19. Highly enantioselective aza-Diels-Alder reaction of 1-azadienes with enecarbamates catalyzed by chiral phosphoric acids.

    PubMed

    He, Long; Laurent, Gregory; Retailleau, Pascal; Folléas, Benoît; Brayer, Jean-Louis; Masson, Géraldine

    2013-10-11

    On demand: A highly enantio- and diastereoselective synthesis of 6-amino- trisubstituted tetrahydropyridine compounds has been developed through the inverse-electron-demand aza-Diels-Alder reaction of N-aryl α,β-unsaturated ketimines with enecarbamates (E)-1. Chiral phosphoric acid catalysts achieve simultaneous activation of both the 1-azadiene and dienophile partners.

  20. Strong counteranion effects on the catalytic activity of cationic silicon Lewis acids in Mukaiyama aldol and Diels-Alder reactions.

    PubMed

    Hara, Kenji; Akiyama, Ryuto; Sawamura, Masaya

    2005-12-08

    [chemical reaction: see text]. A toluene-coordinated silyl borate, [Et3Si(toluene)]B(C6F5)4, demonstrated catalytic activities significantly higher than those of Me3SiOTf and Me3SiNTf2 in Mukaiyama aldol and Diels-Alder reactions.

  1. 4. General view of road with grey birch trees looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. General view of road with grey birch trees looking E. - Great Smoky Mountains National Park Roads & Bridges, Heintooga Round Bottom Road & Balsam Mountain Road, Between Blue Ridge Parkway & Big Cove Road, Gatlinburg, Sevier County, TN

  2. How to search for and use 'grey literature' in research.

    PubMed

    Coad, Jane; Hardicre, Jayne; Devitt, Patric

    An ever-growing amount of grey literature is available to nurses, including oral presentations, personal communication, leaflets, newspapers and magazines, unpublished research, internal reports and minutes of meetings. It can be an invaluable research resource.

  3. Standing equine dental surgery.

    PubMed

    Menzies, Robert A; Easley, Jack

    2014-04-01

    Dental surgeries refer to procedures that affect the dental tissues or their supporting structures. With the development of specific, efficacious, and conservative treatments, morbidity risks have been lowered and chances of benefiting the health of equids improved. Advances in quality of sedation, analgesia, and locoregional anesthesia allow a majority of dental surgeries to be performed in the standing patient. This update focuses on an orthograde endodontic technique, a minimally invasive buccotomy technique, with the potential to combine it with a transbuccal screw extraction technique, and revisits the AO pinless external fixator for fractures of the body of the mandible.

  4. 29. DEPENDABLE FORDATHSHELL CORE MACHINES IN THE GREY IRON FOUNDRY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. DEPENDABLE FORDATH-SHELL CORE MACHINES IN THE GREY IRON FOUNDRY INJECTS SAND INTO A CLOSED CORE BOX. SOME OF THE UNITS HEAT THE CORE BOX TO FIX THE RESINS AS THE CORE REMAINS IN THE BOX, OTHERS MERELY SHAPED THE CORE SAND REQUIRING BAKING OF THE CORES TO HARDEN THEM. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  5. Tree species effects on stand transpiration in northern Wisconsin

    NASA Astrophysics Data System (ADS)

    Ewers, B. E.; Mackay, D. S.; Gower, S. T.; Ahl, D. E.; Burrows, S. N.; Samanta, S. S.

    2002-07-01

    We quantified canopy transpiration (EC) using sap flux measurements representing the four major forest types (northern hardwoods, conifer, aspen/fir, and forested wetland) around the WLEF-TV tall tower in northern Wisconsin. In order to scale individual sap flux measurements to EC, we quantified the amount of sapwood area per unit ground area and the spatial distribution of sap flux within trees. Contrary to our hypothesis that all tree species would have the same positive relationship between tree diameter and sapwood depth, white cedar and speckled alder, both wetland species, showed no relationship. We also hypothesized that the conifer trees would have a lower whole tree hydraulic conductance than deciduous trees. We actually discovered that white cedar had the highest hydraulic conductance. Our third hypothesis, that sapwood area per unit ground area would determine stand EC, was not rejected. The resulting average daily EC values over 53 days (23 June to 16 August 2000) from combining sap flux and sapwood area per unit ground area were 1.4, 0.8, 2.1, and 1.4 mm d-1 for conifer, northern hardwoods, aspen/fir, and forested wetland cover types, respectively. Average daily EC was only explained by an exponential saturation with daily average vapor pressure deficit.

  6. Diversity-Oriented Approaches to Polycyclics and Bioinspired Molecules via the Diels-Alder Strategy: Green Chemistry, Synthetic Economy, and Beyond.

    PubMed

    Kotha, Sambasivarao; Chavan, Arjun S; Goyal, Deepti

    2015-05-11

    We describe diverse approaches to various dienes and their utilization in the Diels-Alder reaction to produce a variety of polycycles. The dienes covered here are prepared by simple alkylation reaction or via the Claisen rearrangement or by enyne metathesis of alkyne or enyne building blocks. Here, we have also included the Diels-Alder chemistry of dendralenes, a higher analog of cross-conjugated dienes. The present article is inclusive of o-xylylene derivatives that are generated in situ starting with benzosultine or benzosulfone derivatives. The Diels-Alder reaction of these dienes with various dienophiles gave diverse polycyclic systems and biologically important targets.

  7. Synthesis of tetrasubstituted 1-silyloxy-3-aminobutadienes and chemistry beyond Diels–Alder reactions

    PubMed Central

    Li, Xijian; Peng, Siyu; Li, Li; Huang, Yong

    2015-01-01

    Electron-rich dienes have revolutionized the synthesis of complex compounds since the discovery of the legendary Diels–Alder cycloaddition reaction. This highly efficient bond-forming process has served as a fundamental strategy to assemble many structurally formidable molecules. Amino silyloxy butadienes are arguably the most reactive diene species that are isolable and bottleable. Since the pioneering discovery by Rawal, 1-amino-3-silyloxybutadienes have been found to undergo cycloaddition reactions with unparalleled mildness, leading to significant advances in both asymmetric catalysis and total synthesis of biologically active natural products. In sharp contrast, this class of highly electron-rich conjugated olefins has not been studied in non-cycloaddition reactions. Here we report a simple synthesis of tetrasubstituted 1-silyloxy-3-aminobutadienes, a complementarily substituted Rawal's diene. This family of molecules is found to undergo a series of intriguing chemical transformations orthogonal to cycloaddition reactions. Structurally diverse polysubstituted ring architectures are established in one step from these dienes. PMID:25898310

  8. Click and Patterned Functionalization of Graphene by Diels-Alder Reaction.

    PubMed

    Li, Jing; Li, Meng; Zhou, Li-Li; Lang, Shuang-Yan; Lu, Hai-Yan; Wang, Dong; Chen, Chuan-Feng; Wan, Li-Jun

    2016-06-22

    Chemical functionalization is a promising approach to controllably manipulate the characteristics of graphene. Here, we designed cis-dienes, featuring two dihydronaphthalene backbones, to decorate a graphene surface via Diels-Alder (DA) click reaction. The installation of a diene moiety into a nonplanar molecular structure to form cis-conformation enables a rapid (∼5 min) DA reaction between graphene and diene groups. Patterned graphene of sub-micrometer resolution can be obtained by easily soaking poly(methyl methacrylate)-masked graphene in solution of hydroxyl-substituted cis-diene at room temperature. The functionalization degree can be further controlled by carrying out the reaction at higher temperature. The present result gives important insight into the effect of molecular conformation on the graphene functionalization process, and provides an effective and facile method for graphene functionalization.

  9. (18)F-Based Pretargeted PET Imaging Based on Bioorthogonal Diels-Alder Click Chemistry.

    PubMed

    Meyer, Jan-Philip; Houghton, Jacob L; Kozlowski, Paul; Abdel-Atti, Dalya; Reiner, Thomas; Pillarsetty, Naga Vara Kishore; Scholz, Wolfgang W; Zeglis, Brian M; Lewis, Jason S

    2016-02-17

    A first-of-its-kind (18)F pretargeted PET imaging approach based on the bioorthogonal inverse electron demand Diels-Alder (IEDDA) reaction between tetrazine (Tz) and trans-cyclooctene (TCO) is presented. As proof-of-principle, a TCO-bearing immunoconjugate of the anti-CA19.9 antibody 5B1 and an Al[(18)F]NOTA-labeled tetrazine radioligand were harnessed for the visualization of CA19.9-expressing BxPC3 pancreatic cancer xenografts. Biodistribution and (18)F-PET imaging data clearly demonstrate that this methodology effectively delineates tumor mass with activity concentrations up to 6.4 %ID/g at 4 h after injection of the radioligand.

  10. Impact of Lewis acids on Diels-Alder reaction reactivity: a conceptual density functional theory study.

    PubMed

    Xia, Yue; Yin, Dulin; Rong, Chunying; Xu, Qiong; Yin, Donghong; Liu, Shubin

    2008-10-09

    Density functional theory (DFT) and conceptual/chemical DFT studies are carried out in this work for the normal electron demand Diels-Alder reaction between isoprene and acrolein to compare chemical reactivity and regioselectivity of the reactants in the absence and presence of Lewis acid (LA) catalysts. A cyclic coplanar structure of acrolein-LA complex has been observed and the natural bond orbital analysis has been employed to interpret the interaction between acrolein and LAs. Reactivity indices from frontier molecular orbital energies are proved to be adequate and efficient to evaluate the catalytic property of LAs. Linear relationships have been discovered among the bond order, bond length, catalytic activation, and chemical reactivity for the systems concerned. The validity and applicability of maximum hardness principle, minimum polarizability principle, and minimum electrophilicity principle are examined and discussed in the prediction of the major regioselective isomer and the preferred reaction pathway for the reactions in the present study.

  11. Bio‐orthogonal Fluorescent Labelling of Biopolymers through Inverse‐Electron‐Demand Diels–Alder Reactions

    PubMed Central

    Kozma, Eszter; Demeter, Orsolya

    2017-01-01

    Abstract Bio‐orthogonal labelling schemes based on inverse‐electron‐demand Diels–Alder (IEDDA) cycloaddition have attracted much attention in chemical biology recently. The appealing features of this reaction, such as the fast reaction kinetics, fully bio‐orthogonal nature and high selectivity, have helped chemical biologists gain deeper understanding of biochemical processes at the molecular level. Listing the components and discussing the possibilities and limitations of these reagents, we provide a recent snapshot of the field of IEDDA‐based biomolecular manipulation with special focus on fluorescent modulation approaches through the use of bio‐orthogonalized building blocks. At the end, we discuss challenges that need to be addressed for further developments in order to overcome recent limitations and to enable researchers to answer biomolecular questions in more detail. PMID:28070925

  12. Characterization of vanadium ion uptake in sulfonated diels alder poly(phenylene) membranes

    DOE PAGES

    Lawton, Jamie; Jones, Amanda; Tang, Zhijiang; ...

    2015-11-28

    Sulfonated diels alder poly(phenylene) (SDAPP), alternative aromatic hydrocarbon membranes for vanadium redox flow batteries (VRFBs) are characterized using electron paramagnetic resonance (EPR). Membranes soaked in sulfuric acid and vanadyl sulfate are analyzed to determine the membrane environment in which the vanadyl ion (VO2+) diffuses in the membranes. These results are compared to Nafion 117 membranes. In contrast to Nafion, the VO2+ in SDAPP membranes exists in two different environments. The results of analysis of rotational diffusion determined from fits the EPR spectral lineshapes in comparison with previously reported permeation studies and measurements of partitioning functions reported here suggest that themore » diffusion pathways in SDAPP are very different than in Nafion.« less

  13. Carbocations as Lewis acid catalysts in Diels-Alder and Michael addition reactions.

    PubMed

    Bah, Juho; Franzén, Johan

    2014-01-20

    In general, Lewis acid catalysts are metal-based compounds that owe their reactivity to a low-lying empty orbital. However, one potential Lewis acid that has received negligible attention as a catalyst is the carbocation. We have demonstrated the potential of the carbocation as a highly powerful Lewis acid catalyst for organic reactions. The stable and easily available triphenylmethyl (trityl) cation was found to be a highly efficient catalyst for the Diels-Alder reaction for a range of substrates. Catalyst loadings as low as 500 ppm, excellent yields, and good endo/exo selectivities were achieved. Furthermore, by changing the electronic properties of the substituents on the tritylium ion, the Lewis acidity of the catalyst could be tuned to control the outcome of the reaction. The ability of this carbocation as a Lewis acid catalyst was also further extended to the Michael reaction.

  14. Economic considerations in establishing European alder in herbaceous cover on surface-mined land

    SciTech Connect

    Ringe, J.M.; Graves, D.H.

    1985-12-09

    Herbicides are a practical tool for selectively controlling vegetative competition during tree seedling establishment. A study to investigate the effects of eight herbicide treatments on the survival and height growth of European alder (Alnus glutinosa) seedlings established in herbaceous cover indicated a positive treatment effect, but very little difference between the herbicide treatments themselves. Since the costs of the herbicides varied considerably, similar results could be obtained using the different herbicides, but at substantially different costs. Biological data were combined with the economic data to derive a modified benefit/cost ratio. This ratio facilitates herbicide treatment choice by comparing the amount of added survival or growth obtained per dollar spent on herbicides. 5 references, 6 tables.

  15. Effect of Diels-Alder Reaction in C60-Tetracene Photovoltaic Devices.

    PubMed

    Proudian, Andrew P; Jaskot, Matthew B; Lyiza, Christelle; Diercks, David R; Gorman, Brian P; Zimmerman, Jeramy D

    2016-10-12

    Developing organic photovoltaic materials systems requires a detailed understanding of the heterojunction interface, as it is the foundation for photovoltaic device performance. The bilayer fullerene/acene system is one of the most studied models for testing our understanding of this interface. We demonstrate that the fullerene and acene molecules chemically react at the heterojunction interface, creating a partial monolayer of a Diels-Alder cycloadduct species. Furthermore, we show that the reaction occurs during standard deposition conditions and that thermal annealing increases the concentration of the cycloadduct. The cycloaddition reaction reduces the number of sites available at the interface for charge transfer exciton recombination and decreases the charge transfer state reorganization energy, increasing the open circuit voltage. The submonolayer quantity of the cycloadduct renders it difficult to identify with conventional characterization techniques; we use atom probe tomography to overcome this limitation while also measuring the spatial distribution of each chemical species.

  16. Poly /Diels-Alder/ matrix resins. [high temperature resistant graphite reinforced composites

    NASA Technical Reports Server (NTRS)

    Jones, R. J.; Orell, M. K.; Sheppard, C. H.; Vaughan, R. W.

    1977-01-01

    A poly (Diels-Alder) (PDA) resin approach was investigated as a means to achieve autoclavability of high-temperature resistant resin/fiber composites under mild fabrication conditions. The results of the study were highly promising and program objectives were achieved. Low-void content Type A-S graphite reinforced composites were autoclave fabricated from a PDA resin/fiber prepreg prepared from an acetone:methanol:dioxane varnish. Autoclave conditions were 400 F and 100 psi for up to two hours duration. After postcure at temperatures up to 600 F, the composites demonstrated high initial mechanical properties at temperatures up to 550 F. The results from isothermal aging studies in air for 1000 hours indicated potential for long-term (over 1000 hours) use at 500 F and shorter-term use at 550 F.

  17. Total synthesis of (+)-gelsemine via an organocatalytic Diels–Alder approach

    PubMed Central

    Chen, Xiaoming; Duan, Shengguo; Tao, Cheng; Zhai, Hongbin; Qiu, Fayang G.

    2015-01-01

    The structurally complex alkaloid gelsemine was previously thought to have no significant biological activities, but a recent study has shown that it has potent and specific antinociception in chronic pain. While this molecule has attracted significant interests from the synthetic community, an efficient synthetic strategy is still the goal of many synthetic chemists. Here we report the asymmetric total synthesis of (+)-gelsemine, including a highly diastereoselective and enantioselective organocatalytic Diels–Alder reaction, an efficient intramolecular trans-annular aldol condensation furnishing the prolidine ring and establishing the configuration of the C20 quaternary carbon stereochemical centre. The entire gelsemine skeleton was constructed through a late-stage intramolecular SN2 substitution. The enantiomeric excess of this total synthesis is over 99%, and the overall yield is around 5%. PMID:25995149

  18. Dynamics of methane production, sulfate reduction, and denitrification in a permanently waterlogged alder swamp

    SciTech Connect

    Westermann, P.; Ahring, B.K.

    1987-10-01

    The dynamics of sulfate reduction, methane production, and denitrification were investigated in a permanently waterlogged alder swamp. Molybdate, an inhibitor of sulfate reduction, stimulated methane production in soil slurries, thus suggesting competition for common substrates between sulfate-reducing and methane-producing bacteria. Acetate, hydrogen, and methanol were found to stimulate both sulfate reduction and methane production, while trimethylamine mainly stimulated methane production. Nitrate addition reduced both methane production and sulfate reduction, either as a consequence of competition of poisoning of the bacteria. Sulfate-reducing bacteria were only slightly limited by the availability of electron acceptors, while denitrifying bacteria were seriously limited by low nitrate concentrations. Arrhenius plots of the three processes revealed different responses to temperature changes in the slurries. Methane production was most sensitive to temperature changes, followed by denitrification and sulfate reduction. No significant differences between slope patterns were observed when comparing summer and winter measurements, indicating similar populations regarding temperature responses.

  19. Characterization of vanadium ion uptake in sulfonated diels alder poly(phenylene) membranes

    SciTech Connect

    Lawton, Jamie; Jones, Amanda; Tang, Zhijiang; Lindsey, Melanie; Zawodzinski, Thomas A

    2015-11-28

    Sulfonated diels alder poly(phenylene) (SDAPP), alternative aromatic hydrocarbon membranes for vanadium redox flow batteries (VRFBs) are characterized using electron paramagnetic resonance (EPR). Membranes soaked in sulfuric acid and vanadyl sulfate are analyzed to determine the membrane environment in which the vanadyl ion (VO2+) diffuses in the membranes. These results are compared to Nafion 117 membranes. In contrast to Nafion, the VO2+ in SDAPP membranes exists in two different environments. The results of analysis of rotational diffusion determined from fits the EPR spectral lineshapes in comparison with previously reported permeation studies and measurements of partitioning functions reported here suggest that the diffusion pathways in SDAPP are very different than in Nafion.

  20. Thiourea-catalyzed Diels–Alder reaction of a naphthoquinone monoketal dienophile

    PubMed Central

    Kramer, Carsten S

    2013-01-01

    Summary A variety of organocatalysts were screened for the catalysis of the naphthoquinone monoketal Diels–Alder reaction. In this study we found that Schreiner's thiourea catalyst 10 and Jacobson's thiourea catalyst 12 facilitate the cycloaddition of the sterically hindered naphthoquinone monoketal dienophile 3 with diene 4. The use of thiourea catalysis allowed for the first time the highly selective synthesis of the exo-product 2a in up to 63% yield. In this reaction a new quaternary center was built. The so formed cycloaddition product 2a represents the ABC tricycle of beticolin 0 (1) and is also a valuable model substrate for the total synthesis of related natural products. PMID:23946836

  1. Salmonberry and salal annual aerial stem production: The maintenance of shrub cover in forest stands

    USGS Publications Warehouse

    Tappeiner, J. C.; Zasada, J.; Huffman, D.; Ganio, L.

    2001-01-01

    Annual sprouting of aerial stems and ramets enables populations of salmonberry (Rubus spectabilis Pursh), salal (Gaultheria shallon Pursh), and probably other forest shrubs to maintain dense covers (>20 000 stems/ha). We studied annual stem production of salmonberry on cut (all stems cut within 15 cm of the ground) and uncut (stems were not treated) plots for 8 years and salal for 5 years in the understories of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), alder, and riparian stands, as well as clearcuts, which are all common stand types in western Oregon. Mean salmonberry stem production on uncut plots ranged from 4.7 stemsA?ma??2A?yeara??1 (95% CI 2.9a??7.4) in alder stands and clearcuts to 1.6 stemsA?ma??2A?yeara??1 (95% CI 1.0a??2.6) in conifer stands. Mean salal production was greater, ranging from 58 stemsA?ma??2A?yeara??1 (95% CI 25a??135) to 8.6 stemsA?ma??2A?yeara??1 (95% CI 3.7a??20.1) on uncut plots in clearcuts and unthinned Douglas-fir stands, respectively. Annual production of both species was somewhat greater on cut plots. Most stems produced in early spring die by December, but enough are recruited to replace mortality of older stems. Stem density was maintained for 8 years for salmonberry and 5 years for salal on both cut and uncut plots. Based on length of rhizomes and bud density we estimate that only 1a??5% of the buds in the rhizomes are needed to support this annual stem production. Although these species sprout vigorously after their aerial stems are killed, disturbance is not necessary for maintaining a dense cover. It appears that, once established, salal, salmonberry, and probably other clonal forest shrubs can maintain a dense cover that can interfere with establishment of trees and other shrubs in canopy gaps or other openings.

  2. The inverse electron demand Diels-Alder click reaction in radiochemistry.

    PubMed

    Reiner, Thomas; Zeglis, Brian M

    2014-04-01

    The inverse electron-demand Diels-Alder (IEDDA) cycloaddition between 1,2,4,5-tetrazines and strained alkene dienophiles is an emergent variety of catalyst-free 'click' chemistry that has the potential to have a transformational impact on the synthesis and development of radiopharmaceuticals. The ligation is selective, rapid, high-yielding, clean, and bioorthogonal and, since its advent in 2008, has been employed in a wide variety of chemical settings. In radiochemistry, the reaction has proven particularly useful with (18)  F and has already been utilized to create a number of (18)  F-labeled agents, including the PARP1-targeting small molecule (18)  F-AZD2281, the αv β3 integrin-targeting peptide (18)  F-RGD, and the GLP-1-targeting peptide (18)  F-exendin. The inherent flexibility of the ligation has also been applied to the construction of radiometal-based probes, specifically the development of a modular strategy for the synthesis of radioimmunoconjugates that effectively eliminates variability in the construction of these agents. Further, the exceptional speed and biorthogonality of the reaction have made it especially promising in the realm of in vivo pretargeted imaging and therapy, and pretargeted imaging strategies based on the isotopes (111) In, (18)  F, and (64) Cu have already proven capable of producing images with high tumor contrast and low levels of uptake in background, nontarget organs. Ultimately, the characteristics of inverse electron-demand Diels-Alder click chemistry make it almost uniquely well-suited for radiochemistry, and although the field is young, this ligation has the potential to make a tremendous impact on the synthesis, development, and study of novel radiopharmaceuticals.

  3. Development and applications of Diels-Alder cycloadditions of 2'-hydroxychalcones

    NASA Astrophysics Data System (ADS)

    Cong, Huan

    Single electron transfer (SET)-initiated formal [4+2] cycloadditions of 2'-hydroxychalcones have been achieved employing a combination of Lewis acid and electron donor as catalyst. Mechanistic studies using cyclic voltammetry (CV) and deuterium labeling experiments suggested a radical anion-mediated stepwise mechanism. The utility of this methodology was established in the first total synthesis of natural product nicolaioidesin C. A novel silica-supported silver nanoparticle (AgNP) catalyst has been developed as a highly active, reusable, and user-friendly catalyst for Diels-Alder cycloadditions of 2'-hydroxychalcones, as showcased by the first total synthesis of natural product panduratin A. Our work demonstrates results from an interdisciplinary research project involving synthetic methodology development, nanometric material preparation, heterogeneous catalysis, natural product synthesis, and mechanistic studies using various instrumental techniques. Biomimetic, dehydrogenative cycloadditions of 2'-hydroxychalcones have been achieved using a mixture of platinum on activated carbon (Pt/C) and silica-supported silver nanoparticles (AgNP's) catalysts. This heterogeneous multicatalytic protocol converts a prenyl subunit in situ to diene which subsequently reacts with a 2'-hyroxychalcone dienophile to provide Diels-Alder cycloadducts in a single step. Using this methodology, a concise synthesis of the core structure of the natural product brosimone B has been accomplished. Enantioselective cycloadditions of 2'-hydroxychalcones have been established with excellent yields and enantioselectivity. Two optimized catalytic conditions have been developed: the first method utilizes a catalyst system comprised of chiral rare earth metal complex and electron donor; the second approach involves a chiral borate catalyst. The asymmetric total synthesis of natural product (+)-sorocenol B has been pursued.

  4. Tyrosine-lipid peroxide adducts from radical termination: para coupling and intramolecular Diels-Alder cyclization.

    PubMed

    Shchepin, Roman; Möller, Matias N; Kim, Hye-young H; Hatch, Duane M; Bartesaghi, Silvina; Kalyanaraman, Balaraman; Radi, Rafael; Porter, Ned A

    2010-12-15

    Free radical co-oxidation of polyunsaturated lipids with tyrosine or phenolic analogues of tyrosine gave rise to lipid peroxide-tyrosine (phenol) adducts in both aqueous micellar and organic solutions. The novel adducts were isolated and characterized by 1D and 2D NMR spectroscopy as well as by mass spectrometry (MS). The spectral data suggest that the polyunsaturated lipid peroxyl radicals give stable peroxide coupling products exclusively at the para position of the tyrosyl (phenoxy) radicals. These adducts have characteristic (13)C chemical shifts at 185 ppm due to the cross-conjugated carbonyl of the phenol-derived cyclohexadienone. The primary peroxide adducts subsequently undergo intramolecular Diels-Alder (IMDA) cyclization, affording a number of diastereomeric tricyclic adducts that have characteristic carbonyl (13)C chemical shifts at ~198 ppm. All of the NMR HMBC and HSQC correlations support the structure assignments of the primary and Diels-Alder adducts, as does MS collision-induced dissociation data. Kinetic rate constants and activation parameters for the IMDA reaction were determined, and the primary adducts were reduced with cuprous ion to give a phenol-derived 4-hydroxycyclohexa-2,5-dienone. No products from adduction of peroxyls at the phenolic ortho position were found in either the primary or cuprous reduction product mixtures. These studies provide a framework for understanding the nature of lipid-protein adducts formed by peroxyl-tyrosyl radical-radical termination processes. Coupling of lipid peroxyl radicals with tyrosyl radicals leads to cyclohexenone and cyclohexadienone adducts, which are of interest in and of themselves since, as electrophiles, they are likely targets for protein nucleophiles. One consequence of lipid peroxyl reactions with tyrosyls may therefore be protein-protein cross-links via interprotein Michael adducts.

  5. Assessment of global grey water footprint of major food crops

    NASA Astrophysics Data System (ADS)

    Yang, Hong; Liu, Wenfeng; Antonelli, Marta

    2016-04-01

    Agricultural production is one of the major sources of water pollution in the world. This is closely related to the excess application of fertilizers. Leaching of N and P to water bodies has caused serious degradation of water quality in many places. With the persistent increase in the demand for agricultural products, agricultural intensification evident during the past decades will continue in the future. This will lead to further increase in fertilizer application and consequently water pollution. Grey water footprint is a measure of the intensity of water pollution caused by water use for human activities. It is defined as the volume of water that is required to assimilate a load of pollutants to a freshwater body, based on natural background concentrations and water quality standards. This study conducts a global assessment of grey water footprint for major cereal crops, wheat, maize and rice. A crop model, Python-based EPIC (PEPIT), is applied to quantify the leaching of N and P from the fertilizer application in the three crops on a global scale with 0.5 degree spatial resolution. The hotspots of leaching are identified. The results suggest that, based on the definition and method of grey water footprint proposed by the World Water Footprint Network, the grey water footprint in many parts of the world has exceeded their total water resources availability. This indicates the seriousness of water pollution caused by agricultural production. However, the situation may also call for the development of a realistic measurement of grey water footprint which is more pertinent to water resources management. This paper proposes some alternatives in measuring grey water footprint and also discusses incorporation of grey water footprint assessment into water policy formulation and river basins plan development.

  6. Relationship between grey matter integrity and executive abilities in aging.

    PubMed

    Manard, Marine; Bahri, Mohamed Ali; Salmon, Eric; Collette, Fabienne

    2016-07-01

    This cross-sectional study was designed to investigate grey matter changes that occur in healthy aging and the relationship between grey matter characteristics and executive functioning. Thirty-six young adults (18-30 years old) and 43 seniors (60-75 years old) were included. A general executive score was derived from a large battery of neuropsychological tests assessing three major aspects of executive functioning (inhibition, updating and shifting). Age-related grey matter changes were investigated by comparing young and older adults using voxel-based morphometry and voxel-based cortical thickness methods. A widespread difference in grey matter volume was found across many brain regions, whereas cortical thinning was mainly restricted to central areas. Multivariate analyses showed age-related changes in relatively similar brain regions to the respective univariate analyses but appeared more limited. Finally, in the older adult sample, a significant relationship between global executive performance and decreased grey matter volume in anterior (i.e. frontal, insular and cingulate cortex) but also some posterior brain areas (i.e. temporal and parietal cortices) as well as subcortical structures was observed. Results of this study highlight the distribution of age-related effects on grey matter volume and show that cortical atrophy does not appear primarily in "frontal" brain regions. From a cognitive viewpoint, age-related executive functioning seems to be related to grey matter volume but not to cortical thickness. Therefore, our results also highlight the influence of methodological aspects (from preprocessing to statistical analysis) on the pattern of results, which could explain the lack of consensus in literature.

  7. Morphological measurements and ITS sequences show that the new alder rust in Europe is conspecific with Melampsoridium hiratsukanum in eastern Asia.

    PubMed

    Hantula, J; Kurkela, T; Hendry, S; Yamaguchi, T

    2009-01-01

    Three species of Melampsoridium have been reported to infect hosts in genus Alnus. An epidemic of foliar rust affecting A. glutinosa and A. incana began in Europe in the mid-1990s, and the associated pathogen was identified as Melampsoridium hiratsukanum based on morphology. In this investigation we analyzed the morphology and genetic variation of alder rusts from Europe and Japan and the host specificity of the European epidemic rust. Our results showed that two rusts occur on the leaves of alders native to northern Europe; in Scotland an endemic rust indistinguishable from M. betulinum occurs, whereas alders in areas of Europe affected by the current epidemic were infected by M. hiratsukanum. M. hiratsukanum from naturally infected alder in Finland produced aecia on all Larix species tested but did not infect Betula leaves.

  8. Bisoxazoline-Lewis acid-catalyzed direct-electron demand oxo-hetero-Diels-Alder reactions of N-oxy-pyridine aldehyde and ketone derivatives.

    PubMed

    Landa, Aitor; Richter, Bo; Johansen, Rasmus Lyng; Minkkilä, Anna; Jørgensen, Karl Anker

    2007-01-05

    A general catalytic oxo-hetero-Diels-Alder reaction for pro-chiral aldehyde and ketone N-oxy-pyridines is presented. The catalytic and asymmetric oxo-hetero-Diels-Alder reaction of electron-rich dienes with N-oxy-pyridine-2-carbaldehyde and ketone derivatives, catalyzed by chiral copper(II)-bisoxazoline complexes, gives optically active six-membered oxygen heterocycles in moderate to good yields and with excellent enantioselectivities.

  9. Synthesis of Isochromene-Type Scaffolds via Single-Flask Diels–Alder-[4 + 2]-Annulation Sequence of a Silyl-Substituted Diene with Menadione

    PubMed Central

    2015-01-01

    A sequential Diels–Alder reaction/silicon-directed [4 + 2]-annulation was developed to assemble hydroisochromene-type ring systems from menadione 2. In the first step, a Diels–Alder of the 1-silyl-substituted butadiene 1 with 2 furnished an intermediate cyclic allylsilane. Subsequently, TMSOTf promoted a [4 + 2]-annulation through trapping of an oxonium, generated by condensation between an aldehyde and the TBS protected alcohol resulted in the formation of a cis-fused hydroisochromene 13. PMID:24918110

  10. Synthesis of isochromene-type scaffolds via single-flask Diels-Alder-[4 + 2]-annulation sequence of a silyl-substituted diene with menadione.

    PubMed

    Lee, Jihoon; Panek, James S

    2014-06-20

    A sequential Diels-Alder reaction/silicon-directed [4 + 2]-annulation was developed to assemble hydroisochromene-type ring systems from menadione 2. In the first step, a Diels-Alder of the 1-silyl-substituted butadiene 1 with 2 furnished an intermediate cyclic allylsilane. Subsequently, TMSOTf promoted a [4 + 2]-annulation through trapping of an oxonium, generated by condensation between an aldehyde and the TBS protected alcohol resulted in the formation of a cis-fused hydroisochromene 13.

  11. Regio-, Diastereo-, and Enantioselective Nitroso-Diels-Alder Reaction of 1,3-Diene-1-carbamates Catalyzed by Chiral Phosphoric Acids.

    PubMed

    Pous, Jonathan; Courant, Thibaut; Bernadat, Guillaume; Iorga, Bogdan I; Blanchard, Florent; Masson, Géraldine

    2015-09-23

    Chiral phosphoric acid-catalyzed asymmetric nitroso-Diels-Alder reaction of nitrosoarenes with carbamate-dienes afforded cis-3,6-disubstituted dihydro-1,2-oxazines in high yields with excellent regio-, diastereo-, and enantioselectivities. Interestingly, we observed that the catalyst is able not only to control the enantioselectivity but also to reverse the regioselectivity of the noncatalyzed nitroso-Diels-Alder reaction. The regiochemistry reversal and asynchronous concerted mechanism were confirmed by DFT calculations.

  12. Grey relational clustering associated with CAPRI applied to FPGA placement

    NASA Astrophysics Data System (ADS)

    Wu, Jan-Ou; Fan, Yang-Hsin; Wang, San-Fu

    2016-04-01

    Grey relational clustering is used to minimise wire length during field programmable gate arrays (FPGA) placement and routing. The proposed Grey Relational Clustering Apply to Placement (GRAP) algorithm combines grey relational clustering and convex assigned placement for regular ICs method to construct a placement netlist, which was successfully used to solve the problem of minimising wire length in an FPGA placement. Upon calculating the grey relational grade, GRAP can rank the sequence and analyse the minimal distance in configuration logic blocks based on the grey relational sequence and combined connection-based approaches. The experimental results demonstrate that the GRAP effectively compares the Hibert, Z and Snake with bounding box (BB) cost function in the space-filling curve. The GRAP improved BB cost by 0.753%, 0.324% and 0.096% for the Hilbert, Z and Snake, respectively. This study also compares the critical path with the space-filling curve. The GRAP approach improved the critical path for Snake by 1.3% in the space-filling curve; however, the GRAP increased critical path wire by 1.38% and 0.03% over that of the Hilbert and Z of space-filling curve, respectively.

  13. Where we stand.

    PubMed

    1973-12-01

    To serve the interests of members and to function in the public interest, the California Medical Association must set policies and take positions on current issues affecting the health care of Californians. These policies then guide the activities of the Association in fulfilling its leadership role and its responsibility to the public.Delegates, elected by the membership of CMA's component medical societies, meet annually to deliberate and determine the policies and courses of action for the Association. Between meetings of these Delegates, the CMA Councilors, elected by their district membership, implement the directives of the Delegates and set interim policies. By this democratic process, the membership governs the CMA. Association members must be informed if they are to participate effectively in the affairs of their medical organizations. To disseminate better understanding of CMA's activities, position papers on current issues have been developed. They are based on House of Delegates resolutions and Council actions. Entitled "Where We Stand on Medical and Health Issues," these papers represent the current policy positions of CMA. Each paper is annotated to give the reference source of the policy actions. As with any organization, CMA policies are subject to timely revision. When policies are amended or new policies are adopted, new papers will be developed.

  14. EUV Engineering Test Stand

    SciTech Connect

    Tichenor, D.A.; Kubiak, G.D.; Replogle, W.C.; Klebanoff, L.E.; Wronosky, J.B.; Hale, L.C.; Chapman, H.N.; Taylor, J.S.; Folta, J.A.; Montcalm, C.; Hudyma, R.M.

    2000-02-14

    The Engineering Test Stand (ETS) is an EUV laboratory lithography tool. The purpose of the ETS is to demonstrate EUV full-field imaging and provide data required to support production-tool development. The ETS is configured to separate the imaging system and stages from the illumination system. Environmental conditions can be controlled independently in the two modules to maximize EUV throughput and environmental control. A source of 13.4 nm radiation is provided by a laser plasma source in which a YAG laser beam is focused onto a xenon-cluster target. A condenser system, comprised of multilayer-coated mirrors and grazing-incidence mirrors, collects the EUV radiation and directs it onto a-reflecting reticle. A four-mirror, ring-field optical system, having a numerical aperture of 0.1, projects a 4x-reduction image onto the wafer plane. This design corresponds to a resolution of 70nm at a k{sub 1} of 0.52. The ETS is designed to produce full-field images in step: and-scan mode using vacuum-compatible, one-dimension-long-travel magnetically levitated stages for both reticle and wafer. Reticle protection is incorporated into the ETS design. This paper provides a system overview of the ETS design and specifications.

  15. [Chile: Standing up again].

    PubMed

    Reyes B, Humberto

    2010-03-01

    One of the biggest earthquakes recorded in human history has recently devastated a large part of the Chilean territory and, followed by a Tsunami, destroyed cities, seaports, fishermen's coves, bridges, and countryside houses. This cataclysm affected a large proportion of our population, leaving homeless families, no working tools for work places, hospitals, schools, public buildings, museums. However, the loss of human Uves was small compared to similar disasters. It destroyed part of the national heritage as well as damaged people's living conditions. A national movement started immediately to help and recover, and international resources, both human and technological were also set in motion. As after previous earthquakes in Chile, young M.D.'s and medical students were organized in voluntary groups backed by institutions or by their own organizations and went from large cities as Santiago and others to provide medical and psychological care to those in most need. Young members and students of other health professions (nurses, physical therapists, etc.) were included in these groups or worked in their own ones. National and international experience indicates that the forthcoming months require special care of psychological reactions and sequel (posttraumatic stress symptoms) and health consequences after water pollution, restrictions in housing and deteriorated sanitary conditions. Nevertheless, our country will stand up once more.

  16. Diels-Alder Trapping of Photochemically Generated Dienes with Acrylic Esters: A Novel Approach to Photocured Polymer Film Development

    NASA Technical Reports Server (NTRS)

    Ilhan, Faysal; Tyson, Daniel S.; Smith, Deedee; Meador, Mary Ann; Meador, Michael A.

    2004-01-01

    Diels-Alder cycloadditions have often been utilized in polymer synthesis as an alternative to condensation reactions. In our earlier efforts, we developed a new method for the preparation of linear aromatic polyimides, which employs o-quionodimethanes (o-QDMs), generated by a well-known photochemical reaction: the photoenolization of o-methylphenyl ketones. Photolysis of o-methylbenzophenone 1 produces hydroxy-o-quino- diemthane 2, which can be trapped with dienophiles, such as dimethyl acetylenedicarboxylate, to efficiently yield the corresponding cycloadduct (Scheme 1). Here we extend this approach to a novel photocuring process for development of polymer films. We synthesized a series of molecules with multi o-mehtylphenyl ketone functionalities. We further investigated these molecules as photoreactive monomers to obtain polyester films through Diels-Alder cycloadditions.

  17. Expanding the scope of cyclopropene reporters for the detection of metabolically engineered glycoproteins by Diels–Alder reactions

    PubMed Central

    Späte, Anne-Katrin; Schart, Verena F; Häfner, Julia; Niederwieser, Andrea; Mayer, Thomas U

    2014-01-01

    Summary Monitoring glycoconjugates has been tremendously facilitated by the development of metabolic oligosaccharide engineering. Recently, the inverse-electron-demand Diels–Alder reaction between methylcyclopropene tags and tetrazines has become a popular ligation reaction due to the small size and high reactivity of cyclopropene tags. Attaching the cyclopropene tag to mannosamine via a carbamate linkage has made the reaction even more efficient. Here, we expand the application of cyclopropene tags to N-acylgalactosamine and N-acylglucosamine derivatives enabling the visualization of mucin-type O-glycoproteins and O-GlcNAcylated proteins through Diels–Alder chemistry. Whereas the previously reported cyclopropene-labeled N-acylmannosamine derivative leads to significantly higher fluorescence staining of cell-surface glycoconjugates, the glucosamine derivative gave higher labeling efficiency with protein preparations containing also intracellular proteins. PMID:25298790

  18. Inbreeding and relatedness in Scandinavian grey wolves Canis lupus.

    PubMed

    Ellegren, H

    1999-01-01

    Management of small and threatened populations may require detailed knowledge about the genetic status of individuals and the genetic relatedness between individuals. I show here that individual heterozygosity at a set of 29 microsatellite loci correlates closely to the degree of inbreeding in a captive grey wolf population. Microsatellite allele sharing similarly correlates closely to known relatedness between pairs of individuals. Genotyping the same markers in a small (60-70 individuals) natural population of grey wolves in Sweden, low individual heterozygosities and high values of allele sharing between some animals were found. Since inbreeding depression has been documented in a captive grey wolf population of Scandinavian origin, the results point out an additional risk for the small Swedish wild population.

  19. Efficiency of searching the grey literature in palliative care.

    PubMed

    Cook, A M; Finlay, I G; Edwards, A G; Hood, K; Higginson, I J; Goodwin, D M; Normand, C E; Douglas, H R

    2001-09-01

    A systematic review into palliative care team effectiveness was undertaken which has, inherent in its methodology, grey literature searching. Over 100 letters were written to a systematically chosen range of service providers, commissioners, and experts in combination with requests for information in six UK national cancer/palliative care organization newsletters. In addition, the System for Information on Grey Literature (SIGLE ) database was searched. As a result, 25 document hard copies were received. The documents were, in all but one case (this one study was also highlighted by the SIGLE search), not relevant as they were predominated by annual reports, service descriptions, and needs assessments. In terms of obtaining unpublished studies for possible inclusion in the review, this comprehensive search was unsuccessful and, therefore, it would appear that grey literature searching is not a useful tool in palliative care systematic reviews.

  20. Fluorescence and coloration of grey hair.

    PubMed

    Daly, S; Bianchini, R; Polefka, T; Jumbelic, L; Jachowicz, J

    2009-10-01

    Grey hair samples were collected from 11 individuals and separated into un-pigmented and pigmented fibres (International Hair Importers). Fluorescence measurements were obtained by using a double-grating fluorescence spectrophotometer and a bifurcated fibre optics accessory to measure the spectra directly from the surface of hair at various distances from the fibre root. Colour measurements were carried out by using a Hunter colorimeter. The fluorescence spectra of un-pigmented hair obtained by the excitation at 290 nm show a peak at 356 nm [tryptophan (Trp)], and multi-peak emissions in the range from 395 to 500 nm. A significant variation in the Trp emission intensity at 356 nm vs. the intensity of emission in the 395-500 nm range was observed for hair collected from various individuals with yellow coloured hair producing stronger relative emission in 395-500 nm range. Quantitative measurements of coloration and the calculation of the Yellowness Index (YI) showed linear correlation between YI and the ratio of fluorescence intensities I(440)/I(356) The spectra obtained by excitation at 320 nm showed the emission peaks at 395 nm (unidentified), 420 nm (N-formylkynurenine), 460 nm (kynurenine), and 495 nm (3-hydroxykynurenine), which are the products of oxidative or metabolic conversion of tryptophan. Un-pigmented, yellow hair showed a build-up of the fluorescence band corresponding to 3-hydroxykynurenine at 495 nm. The data also showed the fluorescence quenching effect of melanin resulting in the lowering of the fluorescence intensity of pigmented hair. The spectra obtained at various positions along the fibres demonstrated gradual photo-decomposition of hair chromophores during their lifetimes. This was indicated by a decrease of Trp fluorescence intensity, which was relatively fast (8.10(-4)-1.5.10(-3) [day(-1)] as calculated for hair obtained from various individuals) for un-pigmented hair and slower for pigmented hair. A decrease in Trp emission was accompanied

  1. Quantitative structure-activation barrier relationship modeling for Diels-Alder ligations utilizing quantum chemical structural descriptors

    PubMed Central

    2013-01-01

    Background In the present study, we show the correlation of quantum chemical structural descriptors with the activation barriers of the Diels-Alder ligations. A set of 72 non-catalysed Diels-Alder reactions were subjected to quantitative structure-activation barrier relationship (QSABR) under the framework of theoretical quantum chemical descriptors calculated solely from the structures of diene and dienophile reactants. Experimental activation barrier data were obtained from literature. Descriptors were computed using Hartree-Fock theory using 6-31G(d) basis set as implemented in Gaussian 09 software. Results Variable selection and model development were carried out by stepwise multiple linear regression methodology. Predictive performance of the quantitative structure-activation barrier relationship (QSABR) model was assessed by training and test set concept and by calculating leave-one-out cross-validated Q2 and predictive R2 values. The QSABR model can explain and predict 86.5% and 80% of the variances, respectively, in the activation energy barrier training data. Alternatively, a neural network model based on back propagation of errors was developed to assess the nonlinearity of the sought correlations between theoretical descriptors and experimental reaction barriers. Conclusions A reasonable predictability for the activation barrier of the test set reactions was obtained, which enabled an exploration and interpretation of the significant variables responsible for Diels-Alder interaction between dienes and dienophiles. Thus, studies in the direction of QSABR modelling that provide efficient and fast prediction of activation barriers of the Diels-Alder reactions turn out to be a meaningful alternative to transition state theory based computation. PMID:24171724

  2. Synthesis of polysubstituted 3-hydroxypyridines via the revisited hetero-Diels-Alder reaction of 5-alkoxyoxazoles with dienophiles.

    PubMed

    Sabot, Cyrille; Oueis, Emilia; Brune, Xavier; Renard, Pierre-Yves

    2012-01-18

    A general and single-step access to polysubstituted 3-hydroxypyridine scaffolds via hetero-Diels-Alder (HDA) reactions between readily prepared 5-ethoxyoxazoles and dienophiles is reported. The HDA reaction, run in the presence of Nd(OTf)(3) at room temperature, was successfully applied to various 5-ethoxyoxazoles showing good functional group tolerance, and led to a straightforward process to obtain useful building-blocks.

  3. Controlled spacing of 60-carbon spheres with 1,4-cyclohexadienyl ladders by pairwise Diels-Alder cycloaddition to buckminsterfullerene

    SciTech Connect

    Paquette, L.A.; Graham, R.J.

    1995-05-19

    This article focuses on the synthesis of Buckminsterfullerenes using a pair of Diels-Alder reactions involving C{sub 60} and the multiply unsaturated bisdienes 1 - 3. The achievement of a dumbbell-like structure may not be desirable for solubility, but controlled spacing of the spheres using 1,4-cyclohexadienyl in this manner will lead to other structure-function insights. 20 refs., 2 figs.

  4. Chiral GAP catalysts of phosphonylated imidazolidinones and their applications in asymmetric Diels-Alder and Friedel-Crafts reactions.

    PubMed

    Qiao, Shuo; Mo, Junming; Wilcox, Cody B; Jiang, Bo; Li, Guigen

    2017-02-21

    The design and synthesis of recyclable imidazolidinone catalysts using GAP chemistry/technique was described. Their applications in asymmetric Diels-Alder and Friedel-Crafts reactions with α,β-unsaturated aldehydes resulted in excellent yields and higher enantioselectivities than previous processes. As recyclable small molecular catalysts, phosphonylated imidazolidinones can be recovered and reused for up to three runs without costing significant decrease in catalytic activity.

  5. Enantioselective Diels-Alder reaction of 1,2-dihydropyridines with aldehydes using β-amino alcohol organocatalyst.

    PubMed

    Kohari, Yoshihito; Okuyama, Yuko; Kwon, Eunsang; Furuyama, Taniyuki; Kobayashi, Nagao; Otuki, Teppei; Kumagai, Jun; Seki, Chigusa; Uwai, Koji; Dai, Gang; Iwasa, Tatsuo; Nakano, Hiroto

    2014-10-17

    The enantioselective Diels-Alder reaction of 1,2-dihydropyridines with aldehydes using an easily prepared optically active β-amino alcohol catalyst was found to provide optically active isoquinuclidines, an efficient synthetic intermediate of pharmaceutically important compounds such as oseltamivir phosphate, with a satisfactory chemical yield and enantioselectivity (up to 96%, up to 98% ee). In addition, the obtained highly optically pure isoquinuclidine was easily converted to an optically active piperidine having four successive carbon centers.

  6. A new approach to the synthesis of monomers and polymers incorporating furan/maleimide Diels-Alder adducts

    NASA Astrophysics Data System (ADS)

    Banella, Maria Barbara; Gioia, Claudio; Vannini, Micaela; Colonna, Martino; Celli, Annamaria; Gandini, Alessandro

    2016-05-01

    The Diels-Alder reaction between furan and maleimide moieties is a well-known and widely used strategy to build bio-based macromolecular structures with peculiar properties. The furan-maleimide adducts are thermally reversible because they can be broken above about 120°C and recombined at lower temperatures. At the moment only the monomers exhibiting the furan or the maleimide moieties on their extremity are used in order to get linear or cross-linked polymeric structures. The innovative idea described here consists in using a monomer bearing two carboxylic acidic groups on its extremities and a furan-maleimide Diels-Alder adduct within its structure. This monomer can give rise to classical polycondensation reactions leading to polymers. These polymers (which are polyesters in the present case) can be broken at high temperatures in correspondence of the furane-maleimide Diels-Alder adduct leading to segments exhibiting furan or maleimide moieties at their extremities, which at lower temperature recombine leading to random or block copolymers.

  7. Design Paradigm Utilizing Reversible Diels-Alder Reactions to Enhance the Mechanical Properties of 3D Printed Materials.

    PubMed

    Davidson, Joshua R; Appuhamillage, Gayan A; Thompson, Christina M; Voit, Walter; Smaldone, Ronald A

    2016-07-06

    A design paradigm is demonstrated that enables new functional 3D printed materials made by fused filament fabrication (FFF) utilizing a thermally reversible dynamic covalent Diels-Alder reaction to dramatically improve both strength and toughness via self-healing mechanisms. To achieve this, we used as a mending agent a partially cross-linked terpolymer consisting of furan-maleimide Diels-Alder (fmDA) adducts that exhibit reversibility at temperatures typically used for FFF printing. When this mending agent is blended with commercially available polylactic acid (PLA) and printed, the resulting materials demonstrate an increase in the interfilament adhesion strength along the z-axis of up to 130%, with ultimate tensile strength increasing from 10 MPa in neat PLA to 24 MPa in fmDA-enhanced PLA. Toughness in the z-axis aligned prints increases by up to 460% from 0.05 MJ/m(3) for unmodified PLA to 0.28 MJ/m(3) for the remendable PLA. Importantly, it is demonstrated that a thermally reversible cross-linking paradigm based on the furan-maleimide Diels-Alder (fmDA) reaction can be more broadly applied to engineer property enhancements and remending abilities to a host of other 3D printable materials with superior mechanical properties.

  8. Short-term influence of nitrate on acetylene reduction, photosynthesis and nodule respiration of black alder seedlings

    SciTech Connect

    Cazell, B.H.; Samuelson, L.J.; Seiler, J.R. )

    1990-05-01

    Black alder (Alnus glutinosa L. Gaernt.) has shown significant benefits in several silvicultural applications such as nurse-trees. However, little is known concerning the nitrate/N-fixing interactions. Our objections were to examine the effects of three nitrate levels on acetylene reduction (AR), net photosynthesis (Ps) and nodule respiration (NR). Fifteen month-old black alder rooted cuttings were inoculated with one strain of Frankia inoculum (ARgN22D) at six months, maintained under 16h photoperiod at ambient greenhouse conditions, and fertilized for two months prior to study with a modified Crone's N-free solution. At study initiation seedlings were fertilized for six days with 0, 7.5 or 15 mM NO{sub 3}{sup {minus}}. Measurements of AR, Ps and NR were collected on the second, fourth and sixth day of NO{sub 3}{sup {minus}} application. By day four AR was significantly lowered by 75% for the 15 mM NO{sub 3}{sup {minus}} treatment when compared with the controls. On day six, Ps and NR were lowered significantly by 29% and 59%, respectively, for the 15 mM NO{sub 3}{sup {minus}} treatments when compared to control values. Results suggest any benefit from black alder N-fixation might be negated by nitrate fertilization.

  9. Performance of ectomycorrhizal alders exposed to specific Canadian oil sands tailing stressors under in vivo bipartite symbiotic conditions.

    PubMed

    Beaudoin-Nadeau, Martin; Gagné, André; Bissonnette, Cyntia; Bélanger, Pier-Anne; Fortin, J André; Roy, Sébastien; Greer, Charles W; Khasa, Damase P

    2016-07-01

    Canadian oil sands tailings are predominately sodic residues contaminated by hydrocarbons such as naphthenic acids. These conditions are harsh for plant development. In this study, we evaluated the effect of inoculating roots of Alnus viridis ssp. crispa and Alnus incana ssp. rugosa with ectomycorrhizal fungi in the presence of tailings compounds. Seedlings were inoculated with 7 different strains of Paxillus involutus and Alpova diplophloeus and were grown under different treatments of NaCl, Na2SO4, and naphthenic acids in a growth chamber. Afterwards, seedling survival, height, dry biomass, leaf necrosis, and root mycorrhization rate were measured. Paxillus involutus Mai was the most successful strain in enhancing alder survival, health, and growth. Seedlings inoculated with this strain displayed a 25% increase in survival rate, 2-fold greater biomass, and 2-fold less leaf necrosis compared with controls. Contrary to our expectations, A. diplophloeus was not as effective as P. involutus in improving seedling fitness, likely because it did not form ectomycorrhizae on roots of either alder species. High intraspecific variation characterized strains of P. involutus in their ability to stimulate alder height and growth and to minimize leaf necrosis. We conclude that in vivo selection under bipartite symbiotic conditions is essential to select effective strains that will be of use for the revegetation and reclamation of derelict lands.

  10. Measurement and clinical effect of grey matter pathology in multiple sclerosis.

    PubMed

    Geurts, Jeroen J G; Calabrese, Massimiliano; Fisher, Elizabeth; Rudick, Richard A

    2012-12-01

    During the past 10 years, the intense involvement of the grey matter of the CNS in the pathology of multiple sclerosis has become evident. On gross inspection, demyelination in the grey matter is rather inconspicuous, and lesions in the grey matter are mostly undetectable with traditional MRI sequences. However, the results of immunohistochemical studies have shown extensive involvement of grey matter, and researchers have developed and applied new MRI acquisition methods as a result. Imaging techniques specifically developed to visualise grey matter lesions indicate early involvement, and image analysis techniques designed to measure the volume of grey matter show progressive loss. Together, these techniques have shown that grey matter pathology is associated with neurological and neuropsychological disability, and the strength of this association exceeds that related to white matter lesions or whole brain atrophy. By focusing on the latest insights into the in-vivo measurement of grey matter lesions and atrophy, we can assess their clinical effects.

  11. Review of the technological approaches for grey water treatment and reuses.

    PubMed

    Li, Fangyue; Wichmann, Knut; Otterpohl, Ralf

    2009-05-15

    Based on literature review, a non-potable urban grey water reuse standard is proposed and the treatment alternatives and reuse scheme for grey water reuses are evaluated according to grey water characteristics and the proposed standard. The literature review shows that all types of grey water have good biodegradability. The bathroom and the laundry grey water are deficient in both nitrogen and phosphors. The kitchen grey water has a balanced COD: N: P ratio. The review also reveals that physical processes alone are not sufficient to guarantee an adequate reduction of the organics, nutrients and surfactants. The chemical processes can efficiently remove the suspended solids, organic materials and surfactants in the low strength grey water. The combination of aerobic biological process with physical filtration and disinfection is considered to be the most economical and feasible solution for grey water recycling. The MBR appears to be a very attractive solution in collective urban residential buildings.

  12. Case Report of dirofilariasis in grey wolf in Serbia.

    PubMed

    Gavrilović, Pavle; Blitva-Robertson, Gordana; Özvegy, József; Kiskároly, Ferenc; Becskei, Zsolt

    2014-03-01

    This paper describes a case of dirofilariasis in a two-year old, female grey wolf (Canis lupus lupus). The autopsy revealed the presence of 42 adult forms of Dirofilaria immitis in the pulmonary artery, right ventricle and right atrium, varying in length from 9.5 to 30 cm. This is, to the best of our knowledge, the second report of D. immitis in grey wolves in Serbia. Our finding confirms that the wolf, as a subspecies distinct from the dog, should also be considered as a very suitable definitive host for dirofilariasis.

  13. A Soil Moisture-Heat Based Early Establishment Model of Riparian White Alder (Alnus rhombifolia)

    NASA Astrophysics Data System (ADS)

    Jablkowski, P.; Johnson, E. A.; Martin, Y. E.

    2013-12-01

    Establishment of fluvially dispersed seeds on accreted gravel-sand bars is limited by water availability in streams. Past establishment models have used the stream/water table recession rate, and maximum root growth rate to determine the elevation limit of seedling establishment. This approach neglects the role of the saturated-unsaturated vadose zone in providing water to recently germinated seedlings, the physical processes that determine the soil moisture content, and the effect moisture deficit has on seedling root growth. This study combines a soil moisture-heat budget and a seedling root growth model that responds to soil moisture availability to find the elevation limit of establishment of white alder (Alnus rhombifolia) on vertically accreted bars along the south fork Eel River in the Angelo Coast Range Reserve, California. To establish successfully, seedling roots must maintain a connection with sufficient moisture to avoid water stress. This will depend on the elevation of the bar, the stream recession rate, the root growth rate, and the diurnal cycle of soil moisture. A one-dimensional moisture-heat budget of the top 15 centimeters of sediment was validated at two locations characterized by sand and clay-gravel textures respectively, using soil moisture and temperature measurements at 5, 10 and 15 cm, net radiation, air temperature, humidity, wind velocity and precipitation measured during spring-summer stream recession. Two patterns in soil water content were apparent: an average daily moisture decrease at each depth driven by stream/water table recession, and a diurnal pattern of isothermal liquid and vapour flux increasing soil water content in the upper 15 cm between 12:00 pm and 5:00 pm PDT. To determine seedling root growth rates, white alder seedlings were grown in growth chambers under a range of reduced matric potentials using polyethylene glycol. Root length measurements were made at 4 hour intervals and a quadratic equation was fit to the root

  14. Comparison of grey matter volume and thickness for analysing cortical changes in chronic schizophrenia: a matter of surface area, grey/white matter intensity contrast, and curvature.

    PubMed

    Kong, Li; Herold, Christina J; Zöllner, Frank; Salat, David H; Lässer, Marc M; Schmid, Lena A; Fellhauer, Iven; Thomann, Philipp A; Essig, Marco; Schad, Lothar R; Erickson, Kirk I; Schröder, Johannes

    2015-02-28

    Grey matter volume and cortical thickness are the two most widely used measures for detecting grey matter morphometric changes in various diseases such as schizophrenia. However, these two measures only share partial overlapping regions in identifying morphometric changes. Few studies have investigated the contributions of the potential factors to the differences of grey matter volume and cortical thickness. To investigate this question, 3T magnetic resonance images from 22 patients with schizophrenia and 20 well-matched healthy controls were chosen for analyses. Grey matter volume and cortical thickness were measured by VBM and Freesurfer. Grey matter volume results were then rendered onto the surface template of Freesurfer to compare the differences from cortical thickness in anatomical locations. Discrepancy regions of the grey matter volume and thickness where grey matter volume significantly decreased but without corresponding evidence of cortical thinning involved the rostral middle frontal, precentral, lateral occipital and superior frontal gyri. Subsequent region-of-interest analysis demonstrated that changes in surface area, grey/white matter intensity contrast and curvature accounted for the discrepancies. Our results suggest that the differences between grey matter volume and thickness could be jointly driven by surface area, grey/white matter intensity contrast and curvature.

  15. Study on tunnel settlement prediction method based on parallel grey neural network model

    NASA Astrophysics Data System (ADS)

    Zhu, Lei; Huang, Teng; Shen, Yue-qian; Zeng, Xian-min

    2015-12-01

    In this paper, according to the characteristics of the grey forecast method and the neural network, constructed the parallel grey neural network model(PGNN) and apply to forecast a tunnel monitoring point's settlement displacement data based on Nanjing metro. The results showed that the prediction accuracy of PGNN is significantly higher than that of unitary grey and neural forecast method. proves that the effectiveness of PGNN in the tunnel settlement prediction. Keywords: Tunnel settlement, grey model, neural network model, prediction

  16. Silylium ion-catalyzed challenging Diels-Alder reactions: the danger of hidden proton catalysis with strong Lewis acids.

    PubMed

    Schmidt, Ruth K; Müther, Kristine; Mück-Lichtenfeld, Christian; Grimme, Stefan; Oestreich, Martin

    2012-03-07

    The pronounced Lewis acidity of tricoordinate silicon cations brings about unusual reactivity in Lewis acid catalysis. The downside of catalysis with strong Lewis acids is, though, that these do have the potential to mediate the formation of protons by various mechanisms, and the thus released Brønsted acid might even outcompete the Lewis acid as the true catalyst. That is an often ignored point. One way of eliminating a hidden proton-catalyzed pathway is to add a proton scavenger. The low-temperature Diels-Alder reactions catalyzed by our ferrocene-stabilized silicon cation are such a case where the possibility of proton catalysis must be meticulously examined. Addition of the common hindered base 2,6-di-tert-butylpyridine resulted, however, in slow decomposition along with formation of the corresponding pyridinium ion. Quantitative deprotonation of the silicon cation was observed with more basic (Mes)(3)P to yield the phosphonium ion. A deuterium-labeling experiment verified that the proton is abstracted from the ferrocene backbone. A reasonable mechanism of the proton formation is proposed on the basis of quantum-chemical calculations. This is, admittedly, a particular case but suggests that the use of proton scavengers must be carefully scrutinized, as proton formation might be provoked rather than prevented. Proton-catalyzed Diels-Alder reactions are not well-documented in the literature, and a representative survey employing TfOH is included here. The outcome of these catalyses is compared with our silylium ion-catalyzed Diels-Alder reactions, thereby clearly corroborating that hidden Brønsted acid catalysis is not operating with our Lewis acid. Several simple-looking but challenging Diels-Alder reactions with exceptionally rare dienophile/enophile combinations are reported. Another indication is obtained from the chemoselectivity of the catalyses. The silylium ion-catalyzed Diels-Alder reaction is general with regard to the oxidation level of the

  17. Persistent organic pollutant patterns in grey seals (Halichoerus grypus).

    PubMed

    Roots, O; Zitko, V; Roose, A

    2005-08-01

    The aim of this paper is to examine the patterns of polychlorinated biphenyls (PCB) in the grey seals (Halichoerus grypus) from the Baltic, Northeast and Eastern England, and the St. Lawrence Estuary (Canada). In fact, the feeding habits of the ringed seal (Phoca hispida) include ingestion of major quantities of benthic crustaceans that might cause observed differences obtained in PCBs, whereas the grey seal feed mainly on fish. The profile (percent in mixture) of polychlorinated biphenyls (PCB) 101, 118, 138, 153, and 180, and the total of their concentrations in mg/kg lipid in grey seals from the Baltic, from Northeast and Eastern England, and from the St. Lawrence estuary (Canada), were examined by principal component analysis (PCA). When considering the possible effects of consuming seafood by the grey seal, it is necessary to characterize populations and individuals according to the amounts they consume, since populations in different parts of the world are likely to show big differences in their consumption of seafood. The patterns differ between juveniles and adult animals, but the gender of adults and geography do not appear to play a role.

  18. 20. SIMILAR TO THE SYSTEM INSTALLED IN THE GREY IRON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. SIMILAR TO THE SYSTEM INSTALLED IN THE GREY IRON FOUNDRY, MALLEABLE WORKERS FILLED MOLDS TRAVELING ON A CONVEYOR FROM LADLES ATTACHED TO OVERHEAD RAILS WHILE THEY STOOD ON A PLATFORM MOVING AT THE SAME SPEED AS THE CONVEYOR, CA. 1950 - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  19. The Grey Nomad Phenomenon: Changing the Script of Aging

    ERIC Educational Resources Information Center

    Onyx, Jenny; Leonard, Rosemary

    2007-01-01

    This article explores a relatively new and little understood phenomenon, that of the Australian Grey Nomads. Every year increasing numbers of older Australians take to the road. This article explores the phenomenon both empirically and theoretically. A grounded approach is used by which the experience is explored from an ethnographic account…

  20. SOUTHWEST VIEW OF FOUNDRY FROM TOP OF GREY IRON CUPOLA ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SOUTHWEST VIEW OF FOUNDRY FROM TOP OF GREY IRON CUPOLA SHOWING OPENED TOP OF CUPOLA WITH EMISSION RECOVERY DUCT COMING OFF. TO THE RIGHT IS THE STORAGE AND SHIPPING BUILDING. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  1. Diels Alder polyphenylene anion exchange membrane for nonaqueous redox flow batteries

    DOE PAGES

    Small, Leo J.; Pratt, III, Harry D.; Fujimoto, Cy H.; ...

    2015-10-23

    Here highly conductive, solvent-resistant anionic Diels Alder polyphenylene (DAPP) membranes were synthesized with three different ionic contents and tested in an ionic liquid-based nonaqueous redox flow battery (RFB). These membranes display 3–10× increase in conductivity in propylene carbonate compared to some commercially available (aqueous) anion exchange membranes. The membrane with an ion content of 1.5 meq/g (DAPP1.5) proved too brittle for operation in a RFB, while the membrane with an ion content of 2.5 meq/g (DAPP2.5) allowed excessive movement of solvent and poor electrochemical yields (capacity fade). Despite having lower voltage efficiencies compared to DAPP2.5, the membrane with an intermediatemore » ion content of 2.0 meq/g (DAPP2.0) exhibited higher coulombic efficiencies (96.4% vs. 89.1%) and electrochemical yields (21.6% vs. 10.9%) after 50 cycles. Crossover of the electroactive species was the primary reason for decreased electrochemical yields. Analysis of the anolyte and catholyte revealed degradation of the electroactive species and formation of a film at the membrane-solution interface. Increases in membrane resistance were attributed to mechanical and thermal aging of the membrane; no chemical change was observed. As a result, improvements in the ionic selectivity and ionic conductivity of the membrane will increase the electrochemical yield and voltage efficiency of future nonaqueous redox flow batteries.« less

  2. Diels Alder polyphenylene anion exchange membrane for nonaqueous redox flow batteries

    SciTech Connect

    Small, Leo J.; Pratt, III, Harry D.; Fujimoto, Cy H.; Anderson, Travis M.

    2015-10-23

    Here highly conductive, solvent-resistant anionic Diels Alder polyphenylene (DAPP) membranes were synthesized with three different ionic contents and tested in an ionic liquid-based nonaqueous redox flow battery (RFB). These membranes display 3–10× increase in conductivity in propylene carbonate compared to some commercially available (aqueous) anion exchange membranes. The membrane with an ion content of 1.5 meq/g (DAPP1.5) proved too brittle for operation in a RFB, while the membrane with an ion content of 2.5 meq/g (DAPP2.5) allowed excessive movement of solvent and poor electrochemical yields (capacity fade). Despite having lower voltage efficiencies compared to DAPP2.5, the membrane with an intermediate ion content of 2.0 meq/g (DAPP2.0) exhibited higher coulombic efficiencies (96.4% vs. 89.1%) and electrochemical yields (21.6% vs. 10.9%) after 50 cycles. Crossover of the electroactive species was the primary reason for decreased electrochemical yields. Analysis of the anolyte and catholyte revealed degradation of the electroactive species and formation of a film at the membrane-solution interface. Increases in membrane resistance were attributed to mechanical and thermal aging of the membrane; no chemical change was observed. As a result, improvements in the ionic selectivity and ionic conductivity of the membrane will increase the electrochemical yield and voltage efficiency of future nonaqueous redox flow batteries.

  3. On the method-dependence of transition state asynchronicity in Diels-Alder reactions.

    PubMed

    Linder, Mats; Brinck, Tore

    2013-04-14

    This work discusses the dependence of transition state geometries on the choice of quantum chemical optimization method for the extensively studied Diels-Alder reaction. Rather significant differences are observed between post-Hartree-Fock methods and (hybrid) density functional theory, where the latter predicts larger asynchronicities. The results show that the low MP2 asynchronicity observed is likely artificial. Still, there are significant discrepancies between hybrid and pure density functionals. The role of the exchange functional seems to be most prominent in less activated reacting systems, while the importance of the correlation functional seems to increase as they become more activated by, e.g., an electron-donating group on the diene. To correct the dubious MP2 geometries, we employed the SCS-MP2 protocol for transition state optimization, which leads to significantly better results with respect to CCSD/6-31+G(d) level calculations. We conclude that in order for hybrid functionals to give descriptions consistent with the sample post-Hartree-Fock methods, a balanced combination of both Hartree-Fock exchange (with a couple of exceptions) and a well-behaved correlation functional is required. Given that the benchmark CCSD/6-31+G(d) geometries are sufficient representations, the best geometries were obtained using ωB97X(D), B2PLYP(D) and M06-2X.

  4. Vanadium redox flow battery efficiency and durability studies of sulfonated Diels Alder poly(phenylene)s

    SciTech Connect

    Fujimoto, Cy H.; Kim, Soowhan; Stains, Ronald; Wei, Xiaoliang; Li, Liyu; Yang, Zhenguo

    2012-07-01

    Sulfonated Diels Alder poly(phenylene) (SDAPP) was examined for vanadium redox flow battery (VRFB) use. The ion exchange capacity (IEC) was varied from 1.4, 1.6 and 2.0 meq/g in order to tune the proton conductivity and vanadium permeability. Coulombic efficiencies between 92 to 99% were observed, depending on IEC (lower IEC, higher coulombic efficiencies). In all cases the SDAPP displayed comparable energy efficiencies (88 - 90%) to Nafion 117 (88%) at 50mA/cm2. Membrane durability also was dependent on IEC; SDAPP with the highest IEC lasted slightly over 50 cycles while SDAPP with the lowest IEC lasted over 400 cycles and testing was discontinued only due to time constraints. Accelerated vanadium lifetime studies were initialed with SDAPP, by soaking films in a 0.1 M V5+ and 5.0 M total SO4-2 solution. The rate of degradation was also proportional with IEC; the 2 meq/g sample dissolved within 376 hours, the 1.6 meq/g sample dissolved after 860 hours, while the 1.4 meq/g sample broke apart after 1527 hours.

  5. A Single Molecular Diels-Alder Crosslinker for Achieving Recyclable Cross-Linked Polymers.

    PubMed

    Chen, Shengli; Wang, Fenfen; Peng, Yongjin; Chen, Tiehong; Wu, Qiang; Sun, Pingchuan

    2015-09-01

    A triol-functional crosslinker combining the thermoreversible properties of Diels-Alder (DA) adducts in one molecule is designed, synthesized, and used as an ideal substitute of a traditional crosslinker to prepare thermal recyclable cross-linked polyurethanes with excellent mechanical properties and recyclability in a very simple and efficient way. The recycle property of these materials achieved by the DA/retro-DA reaction at a suitable temperature is verified by differential scanning calorimetry and in situ variable temperature solid-state NMR experiments during the cyclic heating and cooling processes. The thermal recyclability and remending ability of the bulk polyurethanes is demonstrated by three polymer processing methods, including hot-press molding, injection molding, and solution casting. It is notable that all the recycled cross-linked polymers display nearly invariable elongation/stress at break compared to the as-synthesized samples. Further end-group functionalization of this single molecular DA crosslinker provides the potential in preparing a wide range of recyclable cross-linked polymers.

  6. Combinatorial Synthesis of Linearly Condensed Polycyclic Compounds, Including Anthracyclinones, Through Tandem Diels-Alder Additions

    NASA Astrophysics Data System (ADS)

    Vogel, Pierre

    Double exocyclic 1,3-dienes such as 2,3,5,6-tetramethylidene-7-oxabicyclo[2.2.1]heptane and its 1-substituted derivatives undergo two successive Diels-Alder additions with large reactivity difference between the addition of the first equivalent (k 1) and the second equivalent (k 2) of dienophile. This allows one to prepare, through parallel synthesis, a large number of linearly condensed polycyclic systems containing three annulated six-membered rings, including naphthacenyl systems and anthracyclinones. The large k 1/k 2 rate constant ratio is a consequence of the Dimroth principle, the first cycloaddition being significantly more exothermic then the second one. Control of regio- and stereoselectivity of the two successive cycloadditions is possible by 1-substitution of the 2,3,5,6-tetramethylidene-7-oxabicyclo[2.2.1]heptane, for instance by a 1-(dimethoxymethyl) group, or by stereoselective disubstitution of the double diene by arenesulfenyl substituents. Enantiomerically pure anthracyclinones and analogues are obtained using enantiomerically pure dienophiles such as 3-oxo-but-2-en-2-yl esters. The chemistry so-developed has allowed the preparation of enantiomerically pure 6-((aminoalkoxy)oxy)methyl-6,7-dideoxyidarubicinones that are DNA intercalators and inhibitors of topoisomerase II-induced DNA strained religation.

  7. Liquid-Crystalline Ionic Liquids as Ordered Reaction Media for the Diels-Alder Reaction.

    PubMed

    Bruce, Duncan W; Gao, Yanan; Canongia Lopes, José Nuno; Shimizu, Karina; Slattery, John M

    2016-11-02

    Liquid-crystalline ionic liquids (LCILs) are ordered materials that have untapped potential to be used as reaction media for synthetic chemistry. This paper investigates the potential for the ordered structures of LCILs to influence the stereochemical outcome of the Diels-Alder reaction between cyclopentadiene and methyl acrylate. The ratio of endo- to exo-product from this reaction was monitored for a range of ionic liquids (ILs) and LCILs. Comparison of the endo:exo ratios in these reactions as a function of cation, anion and liquid crystallinity of the reaction media, allowed for the effects of liquid crystallinity to be distinguished from anion effects or cation alkyl chain length effects. These data strongly suggest that the proportion of exo-product increases as the reaction media is changed from an isotropic IL to a LCIL. A detailed molecular dynamics (MD) study suggests that this effect is related to different hydrogen bonding interactions between the reaction media and the exo- and endo-transition states in solvents with layered, smectic ordering compared to those that are isotropic.

  8. Returning to the Alder Hey report and its reporting: addressing confusions and improving inquiries.

    PubMed

    Dewar, S; Boddington, P

    2004-10-01

    The Royal Liverpool Children's Inquiry investigated the circumstances leading to the removal, retention, and disposal of human tissue, including children's organs, at the Royal Liverpool Children's NHS Trust (the Alder Hey Hospital). It recommended changes to procedures for obtaining consent for postmortems and retaining organs and tissues for research or education. However, the report contains five areas of confusion. Firstly, it allowed the cultural and historical traditions of horror over the use and misuse of body parts to suffuse the logical analysis of past wrongs and future rights. Secondly, it makes an inappropriate conflation between seeking redress for past wrongs and shaping future policy. Thirdly, the report takes a muddled stance over the value of bodily integrity at burial. Fourthly, the report is inconsistent over the justification for future organ and tissue collections. Fifthly, the notion of "respect" is used with troublesome looseness. The extent to which subsequent policy work has furthered the search for greater ethical clarity over these difficult issues is discussed, together with reflection on three particular improvements that could be made to the process of such an inquiry.

  9. Quantitative rate determination by dynamic nuclear polarization enhanced NMR of a Diels-Alder reaction.

    PubMed

    Zeng, Haifeng; Lee, Youngbok; Hilty, Christian

    2010-11-01

    Emerging techniques for hyperpolarization of nuclear spins, foremost dynamic nuclear polarization (DNP), lend unprecedented sensitivity to nuclear magnetic resonance spectroscopy. Sufficient signal can be obtained from a single scan, and reactions even far from equilibrium can be studied in real-time. When following the progress of a reaction by nuclear magnetic resonance, however, spin relaxation occurs concomitantly with the reaction to alter resonance line intensities. Here, we present a model for accounting for spin-relaxation in such reactions studied by hyperpolarized NMR. The model takes into account auto- and cross-relaxation in dipole-dipole coupled spin systems and is therefore applicable to NMR of hyperpolarized protons, the most abundant NMR-active nuclei. Applied to the Diels-Alder reaction of 1,4-dipheneylbutadiene (DPBD) with 4-phenyl-1,2,4-triazole-3,5-dione (PTD), reaction rates could be obtained accurately and reproducibly. Additional parameters available from the same experiment include relaxation rates of the reaction product, which may yield further information about the molecular properties of the product. The method presented is also compatible with an experiment where a single spin in the reactant is labeled in its spin-state by a selective radio frequency pulse for subsequent tracking through the reaction, allowing the unambiguous identification of its position in the product molecule. In this case, the chemical shift specificity of high-resolution NMR can allow for the simultaneous determination of reaction rates and mechanistic information in one experiment.

  10. Non-grey thermal effects in irradiated planets atmospheres

    NASA Astrophysics Data System (ADS)

    Parmentier, Vivien; Guillot, Tristan; Fortney, Jonathan J.; Marley, Mark S.

    2016-01-01

    The large diversity of exoplanets in terms of irradiation temperature, gravity and chemical composition discovered around stars with different properties call for the development of fast, accurate and versatile atmospheric models. We derive a new, non-grey analytical model for the thermal structure of irradiated exoplanets. Using two different opacity bands in the thermal frequency range, we highlight the dual role of thermal non-grey opacities in shaping the temperature profile of the atmosphere. Opacities dominated by lines enable the upper atmosphere to cool down significantly compared to a grey atmosphere whereas opacities dominated by bands lead both to a significant cooling of the upper atmosphere and a significant heating of the deep atmosphere.We compare our analytical model to a grid of temperature-pressure profiles for solar composition atmospheres obtained with a state-of-the-art numerical model taking into account the full wavelength, temperature and pressure dependence of the opacities. We demonstrate the importance of thermal non-grey opacities in setting the deep temperature of irradiated giant planets atmospheres. In the particular case of highly irradiated planets we show that the presence of TiO in their atmospheres alters both the optical and the thermal opacities. The greenhouse effect - a semi-grey effect - and the "blanketing effect" - an intrisically non-grey effect - contribute equally to set the deep temperature profile of the planet atmosphere. We conclude that non-grey thermal effects are fundamental to understand the deep temperature profile of hot Jupiters.Our calibrated analytical model matches the numerical model within 10% over a wide range of effective temperature, internal temperature and gravities and properly predict the depth of the radiative/convective boundary, an important quantity to understand the cooling history of a giant planet. Such a fast and accurate model can be of great use when numerous temperature profiles need to

  11. Standing Waves on a Shoestring.

    ERIC Educational Resources Information Center

    Hendrix, Laura

    1992-01-01

    Describes the construction of a wave generator used to review the algebraic relationships of wave motion. Students calculate and measure the weight needed to create tension to generate standing waves at the first eight harmonics. (MDH)

  12. Blue and grey water footprint of textile industry in China.

    PubMed

    Wang, Laili; Ding, Xuemei; Wu, Xiongying

    2013-01-01

    Water footprint (WF) is a newly developed idea that indicates impacts of freshwater appropriation and wastewater discharge. The textile industry is one of the oldest, longest and most complicated industrial chains in the world's manufacturing industries. However, the textile industry is also water intensive. In this paper, we applied a bottom-up approach to estimate the direct blue water footprint (WFdir,blue) and direct grey water footprint (WFdir,grey) of China's textile industry at sector level based on WF methodology. The results showed that WFdir,blue of China's textile industry had an increasing trend from 2001 to 2010. The annual WFdir,blue surpassed 0.92 Gm(3)/yr (giga cubic meter a year) since 2004 and rose to peak value of 1.09 Gm(3)/yr in 2007. The original and residuary WFdir,grey (both were calculated based on the concentration of chemical oxygen demand (CODCr)) of China's textile industry had a similar variation trend with that of WFdir,blue. Among the three sub-sectors of China's textile industry, the manufacture of textiles sector's annual WFdir,blue and WFdir,grey were much larger than those of the manufacture of textile wearing apparel, footware and caps sector and the manufacture of chemical fibers sector. The intensities of WFdir,blue and WF(res)dir,grey of China's textile industry were year by year decreasing through the efforts of issuing restriction policies on freshwater use and wastewater generation and discharge, and popularization of water saving and wastewater treatment technologies.

  13. Resolving a Long-Standing Ambiguity: the Non-Planarity of gauche-1,3-BUTADIENE Revealed by Microwave Spectroscopy

    NASA Astrophysics Data System (ADS)

    Martin-Drumel, Marie-Aline; McCarthy, Michael C.; Patterson, David; Eibenberger, Sandra; Buckingham, Grant; Baraban, Joshua H.; Ellison, Barney; Stanton, John F.

    2016-06-01

    The preferred conformation of cis-1,3-butadiene (CH_2=CH-CH=CH_2) has been of long-standing importance in organic chemistry because of its role in Diels-Alder transition states. The molecule could adopt a planar s-cis conformation, in favor of conjugations in the carbon chain, or a non-planar gauche conformation, as a result of steric interactions between the terminal H atoms. To resolve this ambiguity, we have now measured the pure rotational spectrum of this isomer in the microwave region, unambiguously establishing a significant inertial defect, and therefore a gauche conformation. Experimental measurements of gauche-1,3-butadiene and several of its isotopologues using cavity Fourier-transform microwave (FTMW) spectroscopy in a supersonic expansion and chirped-pulse FTMW spectroscopy in a 4 K buffer gas cell will be summarized, as will new quantum chemical calculations.

  14. Diastereoselective Diels–Alder Reactions of N-Sulfonyl-1-aza-1,3-butadienes With Optically Active Enol Ethers: An Asymmetric Variant of the 1-Azadiene Diels–Alder Reaction

    PubMed Central

    Clark, Ryan C.; Pfeiffer, Steven S.

    2008-01-01

    The first detailed study of a room temperature asymmetric Diels–Alder reaction of N-sulfonyl-1-aza-1,3-butadienes enlisting a series of nineteen enol ethers bearing chiral auxilaries is reported with many providing highly diastereoselective (endo and facial diastereoselection) reactions largely the result of an exquisitely organized [4 + 2] cycloaddition transition state. Three new, readily accessible, and previously unexplored auxilaries (18a, 19a and 37a) rationally emerged from the studies and provide remarkable selectivities (for 19a and 37a: 49:1 endo:exo and 48:1 facial selectivity) that promise to be useful in systems beyond those detailed. PMID:16492042

  15. Free-standing chiral plasmonics

    NASA Astrophysics Data System (ADS)

    Leong, Eunice Sok Ping; Deng, Jie; Wu, Siji; Khoo, Eng Huat; Liu, Yan Jun

    2014-11-01

    Chiral plasmonic nanostructures offer the ability to achieve strong optical circular dichroism (CD) activity over a broad spectral range, which has been challenging for chiral molecules. Chiral plasmonic nanostructures have been extensively studied based on top-down and bottom-up fabrication techniques. Particularly, in the top-down electron-beam lithography, 3D plasmonic nanostructure fabrication involves layer-by-layer patterning and complex alignment, which is time-consuming and causes many defects in the structures. Here, we present a free-standing 3D chiral plamonic nanostructures using the electron-beam lithography technique with much simplified fabrication processes. The 3D chiral plasmonic nanostructures consist of a free-standing ultrathin silicon nitride membrane with well-aligned L-shape metal nanostructures on one side and disk-shape ones on the other side. The free-standing membrane provides an ultra-smooth metal/dielectric interface and uniformly defines the gap between the upper and lower layers in an array of chiral nanostructures. Such free-standing chiral plasmonic nanostructures exhibit strong CD at optical frequencies, which can be engineered by simply changing the disk size on one side of the membrane. Experimental results are in good agreement with the finite-difference time-domain simulations. Such free-standing chiral plasmonics holds great potential for chirality analysis of biomolecules, drugs, and chemicals.

  16. Synthesis of novel dendritic 2,2'-bipyridine ligands and their application to Lewis acid-catalyzed diels-alder and three-component condensation reactions.

    PubMed

    Muraki, Takahito; Fujita, Ken-ichi; Kujime, Masato

    2007-10-12

    A series of dendritic ligands with a 2,2'-bipyridine core was synthesized through the coupling of 4,4'-dihydroxy-2,2'-bipyridine with poly(aryl ether) dendrons. The corresponding dendritic Cu(OTf)2 catalysts were used for Diels-Alder and three-component condensation reactions. The dendritic Cu(OTf)2-catalyzed Diels-Alder reaction proceeded smoothly, and these dendritic catalysts could be recycled without deactivation by reprecipitation. Three-component condensation reactions such as Mannich-type reactions also proceeded not only in dichloromethane but also in water. Furthermore, a positive dendritic effect on chemical yields was observed in both Diels-Alder reactions and aqueous-media three-component condensation reactions.

  17. Computational design of a lipase for catalysis of the Diels-Alder reaction.

    PubMed

    Linder, Mats; Hermansson, Anders; Liebeschuetz, John; Brinck, Tore

    2011-04-01

    Combined molecular docking, molecular dynamics (MD) and density functional theory (DFT) studies have been employed to study catalysis of the Diels-Alder reaction by a modified lipase. Six variants of the versatile enzyme Candida Antarctica lipase B (CALB) have been rationally engineered in silico based on the specific characteristics of the pericyclic addition. A kinetic analysis reveals that hydrogen bond stabilization of the transition state and substrate binding are key components of the catalytic process. In the case of substrate binding, which has the greater potential for optimization, both binding strength and positioning of the substrates are important for catalytic efficiency. The binding strength is determined by hydrophobic interactions and can be tuned by careful selection of solvent and substrates. The MD simulations show that substrate positioning is sensitive to cavity shape and size, and can be controlled by a few rational mutations. The well-documented S105A mutation is essential to enable sufficient space in the vicinity of the oxyanion hole. Moreover, bulky residues on the edge of the active site hinders the formation of a sandwich-like nearattack conformer (NAC), and the I189A mutation is needed to obtain enough space above the face of the α,β-double bond on the dienophile. The double mutant S105A/I189A performs quite well for two of three dienophiles. Based on binding constants and NAC energies obtained from MD simulations combined with activation energies from DFT computations, relative catalytic rates (v(cat)/v(uncat)) of up to 103 are predicted.

  18. Harnessing the bioorthogonal inverse electron demand Diels-Alder cycloaddition for pretargeted PET imaging.

    PubMed

    Reiner, Thomas; Lewis, Jason S; Zeglis, Brian M

    2015-02-03

    Due to their exquisite affinity and specificity, antibodies have become extremely promising vectors for the delivery of radioisotopes to cancer cells for PET imaging. However, the necessity of labeling antibodies with radionuclides with long physical half-lives often results in high background radiation dose rates to non-target tissues. In order to circumvent this issue, we have employed a pretargeted PET imaging strategy based on the inverse electron demand Diels-Alder cycloaddition reaction. The methodology decouples the antibody from the radioactivity and thus exploits the positive characteristics of antibodies, while eschewing their pharmacokinetic drawbacks. The system is composed of four steps: (1) the injection of a mAb-trans-cyclooctene (TCO) conjugate; (2) a localization time period during which the antibody accumulates in the tumor and clears from the blood; (3) the injection of the radiolabeled tetrazine; and (4) the in vivo click ligation of the components followed by the clearance of excess radioligand. In the example presented in the work at hand, a (64)Cu-NOTA-labeled tetrazine radioligand and a trans-cyclooctene-conjugated humanized antibody (huA33) were successfully used to delineate SW1222 colorectal cancer tumors with high tumor-to-background contrast. Further, the pretargeting methodology produces high quality images at only a fraction of the radiation dose to non-target tissue created by radioimmunoconjugates directly labeled with (64)Cu or (89)Zr. Ultimately, the modularity of this protocol is one of its greatest assets, as the trans-cyclooctene moiety can be appended to any non-internalizing antibody, and the tetrazine can be attached to a wide variety of radioisotopes.

  19. Actinorhizal Alder Phytostabilization Alters Microbial Community Dynamics in Gold Mine Waste Rock from Northern Quebec: A Greenhouse Study

    PubMed Central

    Callender, Katrina L.; Roy, Sébastien; Khasa, Damase P.; Whyte, Lyle G.; Greer, Charles W.

    2016-01-01

    Phytotechnologies are rapidly replacing conventional ex-situ remediation techniques as they have the added benefit of restoring aesthetic value, important in the reclamation of mine sites. Alders are pioneer species that can tolerate and proliferate in nutrient-poor, contaminated environments, largely due to symbiotic root associations with the N2-fixing bacteria, Frankia and ectomycorrhizal (ECM) fungi. In this study, we investigated the growth of two Frankia-inoculated (actinorhizal) alder species, A. crispa and A. glutinosa, in gold mine waste rock from northern Quebec. Alder species had similar survival rates and positively impacted soil quality and physico-chemical properties in similar ways, restoring soil pH to neutrality and reducing extractable metals up to two-fold, while not hyperaccumulating them into above-ground plant biomass. A. glutinosa outperformed A. crispa in terms of growth, as estimated by the seedling volume index (SVI), and root length. Pyrosequencing of the bacterial 16S rRNA gene for bacteria and the ribosomal internal transcribed spacer (ITS) region for fungi provided a comprehensive, direct characterization of microbial communities in gold mine waste rock and fine tailings. Plant- and treatment-specific shifts in soil microbial community compositions were observed in planted mine residues. Shannon diversity and the abundance of microbes involved in key ecosystem processes such as contaminant degradation (Sphingomonas, Sphingobium and Pseudomonas), metal sequestration (Brevundimonas and Caulobacter) and N2-fixation (Azotobacter, Mesorhizobium, Rhizobium and Pseudomonas) increased over time, i.e., as plants established in mine waste rock. Acetate mineralization and most probable number (MPN) assays showed that revegetation positively stimulated both bulk and rhizosphere communities, increasing microbial density (biomass increase of 2 orders of magnitude) and mineralization (five-fold). Genomic techniques proved useful in investigating

  20. Synthesis of terephthalic acid via Diels-Alder reactions with ethylene and oxidized variants of 5-hydroxymethylfurfural.

    PubMed

    Pacheco, Joshua J; Davis, Mark E

    2014-06-10

    Terephthalic acid (PTA), a monomer in the synthesis of polyethylene terephthalate (PET), is obtained by the oxidation of petroleum-derived p-xylene. There is significant interest in the synthesis of renewable, biomass-derived PTA. Here, routes to PTA starting from oxidized products of 5-hydroxymethylfurfural (HMF) that can be produced from biomass are reported. These routes involve Diels-Alder reactions with ethylene and avoid the hydrogenation of HMF to 2,5-dimethylfuran. Oxidized derivatives of HMF are reacted with ethylene over solid Lewis acid catalysts that do not contain strong Brønsted acids to synthesize intermediates of PTA and its equally important diester, dimethyl terephthalate (DMT). The partially oxidized HMF, 5-(hydroxymethyl)furoic acid (HMFA), is reacted with high pressure ethylene over a pure-silica molecular sieve containing framework tin (Sn-Beta) to produce the Diels-Alder dehydration product, 4-(hydroxymethyl)benzoic acid (HMBA), with 31% selectivity at 61% HMFA conversion after 6 h at 190 °C. If HMFA is protected with methanol to form methyl 5-(methoxymethyl)furan-2-carboxylate (MMFC), MMFC can react with ethylene in the presence of Sn-Beta for 2 h to produce methyl 4-(methoxymethyl)benzenecarboxylate (MMBC) with 46% selectivity at 28% MMFC conversion or in the presence of a pure-silica molecular sieve containing framework zirconium (Zr-Beta) for 6 h to produce MMBC with 81% selectivity at 26% MMFC conversion. HMBA and MMBC can then be oxidized to produce PTA and DMT, respectively. When Lewis acid containing mesoporous silica (MCM-41) and amorphous silica, or Brønsted acid containing zeolites (Al-Beta), are used as catalysts, a significant decrease in selectivity/yield of the Diels-Alder dehydration product is observed.

  1. Can We Use Tree Rings of Black Alder to Reconstruct Lake Levels? A Case Study for the Mecklenburg Lake District, Northeastern Germany

    PubMed Central

    van der Maaten, Ernst; van der Maaten-Theunissen, Marieke; Buras, Allan; Scharnweber, Tobias; Simard, Sonia; Kaiser, Knut; Lorenz, Sebastian; Wilmking, Martin

    2015-01-01

    In this study, we explore the potential to reconstruct lake-level (and groundwater) fluctuations from tree-ring chronologies of black alder (Alnus glutinosa L.) for three study lakes in the Mecklenburg Lake District, northeastern Germany. As gauging records for lakes in this region are generally short, long-term reconstructions of lake-level fluctuations could provide valuable information on past hydrological conditions, which, in turn, are useful to assess dynamics of climate and landscape evolution. We selected black alder as our study species as alder typically thrives as riparian vegetation along lakeshores. For the study lakes, we tested whether a regional signal in lake-level fluctuations and in the growth of alder exists that could be used for long-term regional hydrological reconstructions, but found that local (i.e. site-specific) signals in lake level and tree-ring chronologies prevailed. Hence, we built lake/groundwater-level reconstruction models for the three study lakes individually. Two sets of models were considered based on (1) local tree-ring series of black alder, and (2) site-specific Standardized Precipitation Evapotranspiration Indices (SPEI). Although the SPEI-based models performed statistically well, we critically reflect on the reliability of these reconstructions, as SPEI cannot account for human influence. Tree-ring based reconstruction models, on the other hand, performed poor. Combined, our results suggest that, for our study area, long-term regional reconstructions of lake-level fluctuations that consider both recent and ancient (e.g., archaeological) wood of black alder seem extremely challenging, if not impossible. PMID:26317768

  2. Nitroso Diels-Alder (NDA) Reaction as an Efficient Tool for the Functionalization of Diene-Containing Natural Products

    PubMed Central

    Carosso, Serena; Miller, Marvin J.

    2014-01-01

    This review describes the use of nitroso Diels-Alder reactions for the functionalization of complex diene-containing natural products in order to generate libraries of compounds with potential biological activity. The application of this methodology to the structural modification of a series of natural products (thebaine, steroidal dienes, rapamycin, leucomycin, colchicine, isocolchicine and piperine) is discussed using relevant examples from the literature from 1973 onwards. The biological activity of the resulting compounds is also discussed. Additional comments are provided that evaluate the methodology as a useful tool in organic, bioorganic and medicinal chemistry. PMID:25119424

  3. A Minimal, Unstrained S‐Allyl Handle for Pre‐Targeting Diels–Alder Bioorthogonal Labeling in Live Cells

    PubMed Central

    Oliveira, Bruno L.; Guo, Zijian; Boutureira, Omar; Guerreiro, Ana; Jiménez‐Osés, Gonzalo

    2016-01-01

    Abstract The unstrained S‐allyl cysteine amino acid was site‐specifically installed on apoptosis protein biomarkers and was further used as a chemical handle and ligation partner for 1,2,4,5‐tetrazines by means of an inverse‐electron‐demand Diels–Alder reaction. We demonstrate the utility of this minimal handle for the efficient labeling of apoptotic cells using a fluorogenic tetrazine dye in a pre‐targeting approach. The small size, easy chemical installation, and selective reactivity of the S‐allyl handle towards tetrazines should be readily extendable to other proteins and biomolecules, which could facilitate their labeling within live cells. PMID:27763724

  4. Diels-Alder Reactions of α-Amido Acrylates with N-Cbz-1,2-dihydropyridine and Cyclopentadiene.

    PubMed

    Abas, Hossay; Frampton, Christopher S; Spivey, Alan C

    2016-10-21

    Thermal Diels-Alder reactions of α-amido acrylates with N-Cbz-1,2-dihydropyridine and cyclopentadiene have been explored to investigate the factors influencing the endo/exo selectivity. For the dihydropyridine, steric factors allowed the diastereoselectivity to be modulated to favor either endo- or exo-ester adducts. For cyclopentadiene, the endo-ester adducts were favored regardless of steric perturbation, although catalysis by bulky Lewis acids increased the proportion of exo-ester adducts in some cases. These Lewis acids were incompatible with the dihydropyridine diene as they induced its decomposition.

  5. Elucidation of Diels-Alder Reaction Network of 2,5-Dimethylfuran and Ethylene on HY Zeolite Catalyst

    SciTech Connect

    Do, Phuong T. M.; McAtee, Jesse R.; Watson, Donald A.; Lobo, Raul F.

    2012-12-12

    The reaction of 2,5-dimethylfuran and ethylene to produce p-xylene represents a potentially important route for the conversion of biomass to high-value organic chemicals. Current preparation methods suffer from low selectivity and produce a number of byproducts. Using modern separation and analytical techniques, the structures of many of the byproducts produced in this reaction when HY zeolite is employed as a catalyst have been identified. From these data, a detailed reaction network is proposed, demonstrating that hydrolysis and electrophilic alkylation reactions compete with the desired Diels–Alder/dehydration sequence. This information will allow the rational identification of more selective catalysts and more selective reaction conditions.

  6. Bidentate Lewis Acid Catalyzed Domino Diels-Alder Reaction of Phthalazine for the Synthesis of Bridged Oligocyclic Tetrahydronaphthalenes.

    PubMed

    Schweighauser, Luca; Bodoky, Ina; Kessler, Simon N; Häussinger, Daniel; Donsbach, Carsten; Wegner, Hermann A

    2016-03-18

    A domino process consisting of an inverse and a normal electron-demand Diels-Alder reaction is presented for the formation of bridged tri- and tetracyclic 1,2,3,4-tetrahydronaphthalenes catalyzed by a bidentate Lewis acid. The products were synthesized in a one-pot reaction from commercially available starting materials and contain up to six stereogenic centers. The tetrahydronaphthalenes were isolated as single diastereomers and are derivatives of phenylethylamine, which is well-known as a scaffold of amphetamine or dopamine.

  7. Tandem cross enyne metathesis (CEYM)–intramolecular Diels–Alder reaction (IMDAR). An easy entry to linear bicyclic scaffolds

    PubMed Central

    Miró, Javier; Sánchez-Roselló, María; Sanz, Álvaro; Rabasa, Fernando

    2015-01-01

    Summary A new tandem cross enyne metathesis (CEYM)–intramolecular Diels–Alder reaction (IMDAR) has been carried out. It involves conjugated ketones, esters or amides bearing a remote olefin and aromatic alkynes as the starting materials. The overall process enables the preparation of a small family of linear bicyclic scaffolds in a very simple manner with moderate to good levels of diastereoselectivity. This methodology constitutes one of the few examples that employ olefins differently than ethylene in tandem CEYM–IMDAR protocols. PMID:26425205

  8. Hybrid metal/organo relay catalysis enables enynes to be latent dienes for asymmetric Diels-Alder reaction.

    PubMed

    Han, Zhi-Yong; Chen, Dian-Feng; Wang, Ya-Yi; Guo, Rui; Wang, Pu-Sheng; Wang, Chao; Gong, Liu-Zhu

    2012-04-18

    The hybrid Au(I)/Brønsted acid binary catalyst system enables enynes to serve as latent 1,3-silyloxydienes capable of participating in the first cascade hydrosiloxylation of an enynyl silanol/asymmetric Diels-Alder reaction. A variety of polycyclic compounds bearing multistereogenic centers were obtained in high yields and excellent enantioselectivities from the relay catalytic cascade reaction between (2-(but-3-en-1-ynyl)phenyl) silanols and quinones catalyzed by the combined achiral gold complex and chiral N-triflyl phosphoramide.

  9. One-pot cross-enyne metathesis (CEYM)-Diels-Alder reaction of gem-difluoropropargylic alkynes.

    PubMed

    Fustero, Santos; Bello, Paula; Miró, Javier; Sánchez-Roselló, María; Haufe, Günter; Del Pozo, Carlos

    2013-01-01

    Propargylic difluorides 1 were used as starting substrates in a combination of cross-enyne metathesis and Diels-Alder reactions. Thus, the reaction of 1 with ethylene in the presence of 2(nd) generation Hoveyda-Grubbs catalyst generates a diene moiety which in situ reacts with a wide variety of dienophiles giving rise to a small family of new fluorinated carbo- and heterocyclic derivatives in moderate to good yields. This is a complementary protocol to the one previously described by our research group, which involved the use of 1,7-octadiene as an internal source of ethylene.

  10. Morphology of the lingual papillae in the eastern grey kangaroo.

    PubMed

    Emura, Shoichi

    2016-01-01

    We examined the dorsal lingual surface of an adult eastern grey kangaroo (Macropus gigantues) by scanning electron microscopy. The filiform papillae on the lingual apex and anterior body consisted of a main papilla and secondary papillae. The connective tissue core of the filiform papillae on the lingual apex had several processes. The filiform papillae on the lingual posterior body were thread-like in shape. The connective tissue core of the filiform papillae on the lingual posterior body consisted of many slender processes. The fungiform papillae were round in shape. Three vallate papillae with the apex of the triangle directed posteriorly consisted of a groove and pad. Several conical papillae derived from the posterolateral margin of the tongue where foliate papillae have been shown to be distributed in many other animal species. The surface structure of the tongue in the eastern grey kangaroo resembles that of the red kangaroo.

  11. Improvement of CCME WQI using grey relational method

    NASA Astrophysics Data System (ADS)

    Yan, Feng; Qiao, Danying; Qian, Bao; Ma, Lin; Xing, Xigang; Zhang, You; Wang, Xiaogang

    2016-12-01

    The conventional CCME WQI ignores the uncertainties in aquatic environment, which may lead to biases and abrupt changes in evaluation results. To overcome this shortcoming, this study improves the calculation of CCME WQI using trapezoid grey relational degree method, a model dealing with uncertainties introduced by incomplete information. Compared with the conventional CCME WQI, the grey CCME WQI has a stricter calculation method in synthetic evaluation and a better capacity in water quality warning. The water quality of New Tongyang Canal is evaluated and the result shows that its environment deteriorates with the increasing rainfall and improves with the decreasing precipitation. To decrease its environmental risk, it is suggested to reduce the nutrients in agricultural runoff and the oxygen-consuming pollutants in urban runoff in the rainy season.

  12. 21 CFR 880.6990 - Infusion stand.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Infusion stand. 880.6990 Section 880.6990 Food and....6990 Infusion stand. (a) Identification. The infusion stand is a stationary or movable stand intended to hold infusion liquids, infusion accessories, and other medical devices. (b) Classification....

  13. 21 CFR 880.6990 - Infusion stand.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Infusion stand. 880.6990 Section 880.6990 Food and....6990 Infusion stand. (a) Identification. The infusion stand is a stationary or movable stand intended to hold infusion liquids, infusion accessories, and other medical devices. (b) Classification....

  14. 21 CFR 880.6990 - Infusion stand.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Infusion stand. 880.6990 Section 880.6990 Food and....6990 Infusion stand. (a) Identification. The infusion stand is a stationary or movable stand intended to hold infusion liquids, infusion accessories, and other medical devices. (b) Classification....

  15. Parapox infection in grey seals (Halichoerus grypus) in Cornwall.

    PubMed

    Simpson, V R; Stuart, N C; Stack, M J; Ross, H A; Head, J C

    1994-03-19

    In the winter of 1991/92 there was an outbreak of parapox infection in grey seals (Halichoerus grypus) around the coast of Cornwall. Pups were cared for at a seal rehabilitation centre and the infection occurred in most of them. The presence of parapox virus was confirmed by electron microscopy. The clinical and pathological findings, together with details of the morphology of the virus, are compared with those in previous outbreaks in North America.

  16. Reduced Regional Grey Matter Volumes in Pediatric Obstructive Sleep Apnea

    PubMed Central

    Philby, Mona F.; Macey, Paul M.; Ma, Richard A.; Kumar, Rajesh; Gozal, David; Kheirandish-Gozal, Leila

    2017-01-01

    Pediatric OSA is associated with cognitive risk. Since adult OSA manifests MRI evidence of brain injury, and animal models lead to regional neuronal losses, pediatric OSA patients may also be affected. We assessed the presence of neuronal injury, measured as regional grey matter volume, in 16 OSA children (8 male, 8.1 ± 2.2 years, AHI:11.1 ± 5.9 events/hr), and 200 control subjects (84 male, 8.2 ± 2.0 years), 191 of whom were from the NIH-Pediatric MRI database. High resolution T1-weighted whole-brain images were assessed between groups with voxel-based morphometry, using ANCOVA (covariates, age and gender; family-wise error correction, P < 0.01). Significant grey matter volume reductions appeared in OSA throughout areas of the superior frontal and prefrontal, and superior and lateral parietal cortices. Other affected sites included the brainstem, ventral medial prefrontal cortex, and superior temporal lobe, mostly on the left side. Thus, pediatric OSA subjects show extensive regionally-demarcated grey matter volume reductions in areas that control cognition and mood functions, even if such losses are apparently independent of cognitive deficits. Since OSA disease duration in our subjects is unknown, these findings may result from either delayed neuronal development, neuronal damaging processes, or a combination thereof, and could either reflect neuronal atrophy or reductions in cellular volume (neurons and glia). PMID:28303917

  17. Grey water on three agricultural catchments in the Czech Republic

    NASA Astrophysics Data System (ADS)

    Blazkova, Sarka D.; Kulasova, Alena

    2014-05-01

    The COST project EU EURO-AGRIWAT focuses apart from other problems on the assessment of water footprint (WF). WF is defined as the quantity of water used to produce some goods or a service. In particular, the WF of an agricultural product is the volume of water used during the crop growing period. It has three components: the green water which is rain or soil moisture transpired by a crop, the blue water which is the amount of irrigation water transpired and the grey water which is the volume of water required to dilute pollutants and to restore the quality standards of the water body. We have been observing three different agricultural catchments. The first of them is Smrzovka Brook, located in the protected nature area in the south part of the Jizerske Mountains. An ecological farming has been carried out there. The second agricultural catchment area is the Kralovsky Creek, which lies in the foothills of the Krkonose Mountains and is a part of an agricultural cooperative. The last agricultural catchment is the Klejnarka stream, located on the outskirts of the fertile Elbe lowlands near Caslav. Catchments Kralovsky Brook and Klejnarka carry out usual agricultural activities. On all three catchments, however, recreational cottages or houses not connected to the sewerage system and/or with inefficient septic tanks occur. The contribution shows our approach to trying to quantify the real grey water from agriculture, i.e. the grey water caused by nutrients not utilised by the crops.

  18. Hybrid nuclear reactor grey rod to obtain required reactivity worth

    DOEpatents

    Miller, John V.; Carlson, William R.; Yarbrough, Michael B.

    1991-01-01

    Hybrid nuclear reactor grey rods are described, wherein geometric combinations of relatively weak neutron absorber materials such as stainless steel, zirconium or INCONEL, and relatively strong neutron absorber materials, such as hafnium, silver-indium cadmium and boron carbide, are used to obtain the reactivity worths required to reach zero boron change load follow. One embodiment includes a grey rod which has combinations of weak and strong neutron absorber pellets in a stainless steel cladding. The respective pellets can be of differing heights. A second embodiment includes a grey rod with a relatively thick stainless steel cladding receiving relatively strong neutron absorber pellets only. A third embodiment includes annular relatively weak netron absorber pellets with a smaller diameter pellet of relatively strong absorber material contained within the aperture of each relatively weak absorber pellet. The fourth embodiment includes pellets made of a homogeneous alloy of hafnium and a relatively weak absorber material, with the percentage of hafnium chosen to obtain the desired reactivity worth.

  19. Magnesium therapy in a hypocalcemic African grey parrot (Psittacus erithacus).

    PubMed

    Kirchgessner, Megan S; Tully, Thomas N; Nevarez, Javier; Sanchez-Migallon Guzman, David; Acierno, Mark J

    2012-03-01

    Hypocalcemic-induced seizure activity is a clinical entity that is commonly diagnosed in neurologic African grey parrots (Psittacus erithacus). Plasma calcium levels are typically less than 6.0 mg/dL at the time of seizure activity, and although the underlying cause of the hypocalcemia has not yet been determined, many theories have been proposed. An African grey parrot that had been fed a seed diet for 8 years was presented with hypocalcemia and seizures and exhibited precipitously declining plasma calcium levels, despite aggressive calcium and vitamin A, D, and E supplementation for 4 days. Baseline magnesium levels in this parrot were determined to be 1.9 mg/dL; therefore, magnesium sulfate was administered at a dose of 20 mg/kg IM once. Twenty-four hours after supplementation, the plasma magnesium level was 3.3 mg/dL, and no further seizure activity was observed. We believe that a primary dietary magnesium deficiency may have been present in this African grey parrot, similar to a syndrome in leghorn chicks, which is frequently characterized by progressive hypocalcemia that is unable to be corrected by calcium supplementation alone.

  20. The trajectory prediction of spacecraft by grey method

    NASA Astrophysics Data System (ADS)

    Wang, Qiyue; Zhang, Zili; Wang, Zhongyu; Wang, Yanqing; Zhou, Weihu

    2016-08-01

    The real-time and high-precision trajectory prediction of a moving object is a core technology in the field of aerospace engineering. The real-time monitoring and tracking technology are also significant guarantees of aerospace equipment. A dynamic trajectory prediction method called grey dynamic filter (GDF) which combines the dynamic measurement theory and grey system theory is proposed. GDF can use coordinates of the current period to extrapolate coordinates of the following period. At meantime, GDF can also keep the instantaneity of measured coordinates by the metabolism model. In this paper the optimal model length of GDF is firstly selected to improve the prediction accuracy. Then the simulation for uniformly accelerated motion and variably accelerated motion is conducted. The simulation results indicate that the mean composite position error of GDF prediction is one-fifth to that of Kalman filter (KF). By using a spacecraft landing experiment, the prediction accuracy of GDF is compared with the KF method and the primitive grey method (GM). The results show that the motion trajectory of spacecraft predicted by GDF is much closer to actual trajectory than the other two methods. The mean composite position error calculated by GDF is one-eighth to KF and one-fifth to GM respectively.

  1. Taking Stands for Social Justice

    ERIC Educational Resources Information Center

    Lindley, Lorinda; Rios, Francisco

    2004-01-01

    In this paper the authors describe efforts to help students take a stand for social justice in the College of Education at one predominantly White institution in the western Rocky Mountain region. The authors outline the theoretical frameworks that inform this work and the context of our work. The focus is on specific pedagogical strategies used…

  2. Quartz Crystal Microbalance Analysis of Diels-Alder Reactions of Alkene Gases to Functional Ionic Liquids on Chips.

    PubMed

    Hsu, Tzu-Hsuan; Chiang, Shu-Jen; Chu, Yen-Ho

    2016-11-15

    We demonstrated here a successful development of the use of functional ionic liquids FIL 1 and FIL 3 for chemoselective detection of alkene gases measured by quartz crystal microbalance. This detection of gaseous alkenes was achieved by the Diels-Alder [4 + 2] cycloadditions with FIL 1 and FIL 3 thin-coated on quartz chips. Our functional ionic liquids could be prepared by straightforward synthetic chemistry in short steps and are superior in alkene gas detection. The QCM platform developed in this work is chemoselective with fast gas diffusion into ionic liquids, readily applicable to low molecular weight alkene gases and insensitive to moisture. To the best of our knowledge, this is the first report based upon the Diels-Alder reactions demonstrating sensitive alkene gas detection in ionic liquids on a QCM. This work is a proof-of-concept inspection of the promising use of a QCM-based sensor method for reaction-directed detection of gas samples, which is part of an ongoing program aimed at studying diseases.

  3. Synergistic activation of the Diels-Alder reaction by an organic catalyst and substituents: a computational study.

    PubMed

    Linder, Mats; Brinck, Tore

    2009-04-07

    Density functional theory (DFT), using the hybrid functionals B3LYP and B2PLYP, has been employed to investigate the activation of the acrolein-butadiene Diels-Alder reaction, mediated by a thiourea catalyst. Effects due to electron-donating groups (EDGs) on the diene, as well as electron-withdrawing groups (EWGs) on the dienophile, have also been studied. Organic catalysts such as thioureas are known to lower the activation energy through hydrogen-bonding to the carbonyl oxygen, in a way that mimics the oxyanion holes of hydrolytic enzymes. EDGs and EWGs were found to further activate the reaction, and the catalyst showed a synergistic behavior towards the EDGs. Polar solvents were found to reduce the overall activation energy, but also the relative catalytic effect of the thiourea, in accordance with experimental studies. The substituent-mediated reactions displayed more asynchronous transition structures with lower activation energy, which led us to investigate the possibility of an alternative two-step, Michael-type route, similar to what has been found in macrophomate synthase. Although the concerted Diels-Alder route was found to be favored over the Michael route, the calculated activation energy difference is less than 1 kcal mol(-1), which suggests that the two mechanisms compete, and could be responsible for the particular stereochemical outcome of an experiment.

  4. Magnetic hyaluronic acid nanospheres via aqueous Diels-Alder chemistry to deliver dexamethasone for adipose tissue engineering.

    PubMed

    Jia, Yang; Fan, Ming; Chen, Huinan; Miao, Yuting; Xing, Lian; Jiang, Bohong; Cheng, Qifan; Liu, Dongwei; Bao, Weikang; Qian, Bin; Wang, Jionglu; Xing, Xiaodong; Tan, Huaping; Ling, Zhonghua; Chen, Yong

    2015-11-15

    Biopolymer-based nanospheres have great potential in the field of drug delivery and tissue regenerative medicine. In this work, we present a flexible way to conjugate a magnetic hyaluronic acid (HA) nanosphere system that are capable of vectoring delivery of adipogenic factor, e.g. dexamethasone, for adipose tissue engineering. Conjugation of nanospheres was established by aqueous Diels-Alder chemistry between furan and maleimide of HA derivatives. Simultaneously, a furan functionalized dexamethasone peptide, GQPGK, was synthesized and covalently immobilized into the nanospheres. The magnetic HA nanospheres were fabricated by encapsulating super-paramagnetic iron oxide nanoparticles, which exhibited quick magnetic sensitivity. The aqueous Diels-Alder chemistry made nanospheres high binding efficiency of dexamethasone, and the vectoring delivery of dexamethasone could be easily controlled by a external magnetic field. The potential application of the magnetic HA nanospheres on vectoring delivery of adipogenic factor was confirmed by co-culture of human adipose-derived stem cells (ASCs). In vitro cytotoxicity tests demonstrated that incorporation of dexamethasone into magnetic HA nanospheres showed high efficiency to promote ASCs viabilities, in particular under a magnetic field, which suggested a promising future for adipose regeneration applications.

  5. Detecting Sirex noctilio grey-attacked and lightning-struck pine trees using airborne hyperspectral data, random forest and support vector machines classifiers

    NASA Astrophysics Data System (ADS)

    Abdel-Rahman, Elfatih M.; Mutanga, Onisimo; Adam, Elhadi; Ismail, Riyad

    2014-02-01

    The visual progression of sirex (Sirex noctilio) infestation symptoms has been categorized into three distinct infestation phases, namely the green, red and grey stages. The grey stage is the final stage which leads to almost complete defoliation resulting in dead standing trees or snags. Dead standing pine trees however, could also be due to the lightning damage. Hence, the objective of the present study was to distinguish amongst healthy, sirex grey-attacked and lightning-damaged pine trees using AISA Eagle hyperspectral data, random forest (RF) and support vector machines (SVM) classifiers. Our study also presents an opportunity to look at the possibility of separating amongst the previously mentioned pine trees damage classes and other landscape classes on the study area. The results of the present study revealed the robustness of the two machine learning classifiers with an overall accuracy of 74.50% (total disagreement = 26%) for RF and 73.50% (total disagreement = 27%) for SVM using all the remaining AISA Eagle spectral bands after removing the noisy ones. When the most useful spectral bands as measured by RF were exploited, the overall accuracy was considerably improved; 78% (total disagreement = 22%) for RF and 76.50% (total disagreement = 24%) for SVM. There was no significant difference between the performances of the two classifiers as demonstrated by the results of McNemar's test (chi-squared; χ2 = 0.14, and 0.03 when all the remaining ASIA Eagle wavebands, after removing the noisy ones and the most important wavebands were used, respectively). This study concludes that AISA Eagle data classified using RF and SVM algorithms provide relatively accurate information that is important to the forest industry for making informed decision regarding pine plantations health protocols.

  6. Employing Arynes in Diels-Alder Reactions and Transition-Metal-Free Multicomponent Coupling and Arylation Reactions.

    PubMed

    Bhojgude, Sachin Suresh; Bhunia, Anup; Biju, Akkattu T

    2016-09-20

    Arynes are highly reactive intermediates having several applications in organic synthesis for the construction of various ortho-disubstituted arenes. Traditionally, arynes are generated in solution from haloarenes under strongly basic conditions. However, the scopes of many of the aryne reactions are limited because of the harsh conditions used for their generation. The renaissance of interest in aryne chemistry is mainly due to the mild conditions for their generation by the fluoride-induced 1,2-elimination of 2-(trimethylsilyl)aryl triflates. This Account is focused on the Diels-Alder reaction of arynes and their transition-metal-free application in multicomponent couplings as well as arylation reactions. The Diels-Alder reaction of arynes is a powerful tool for constructing benzo-fused carbocycles and heterocycles. In 2012, we developed an efficient, broad-scope, and scalable Diels-Alder reaction of pentafulvenes with arynes affording benzonorbornadiene derivatives. Subsequently, we accomplished the Diels-Alder reaction of arynes with dienes such as 1,2-benzoquinones and tropones. Moreover, we uncovered a transition-metal-free protocol for the synthesis of 9,10-dihydrophenanthrenes by the reaction of arynes with styrenes that proceeds via a Diels-Alder/ene-reaction cascade. In addition, we demonstrated the reaction of arynes with indene/benzofurans, which proceeds via a tandem [4 + 2]/[2 + 2] sequence. Multicomponent coupling (MCC) involving arynes mainly comprises the initial addition of a nucleophile to the aryne followed by interception of the aryl anion intermediate with an electrophile (provided the nucleophilic and electrophilic moieties do not belong to the same molecule). We have disclosed aryne MCCs initiated by N-heterocycles such as (iso)quinoline, pyridine, and aziridines. When (iso)quinoline is used as the nucleophilic trigger and N-substituted isatin as the third component, the reaction affords spirooxazino(iso)quinolines via 1,4-dipolar

  7. Cellular and ultrastructural characterization of the grey-morph phenotype in southern right whales (Eubalaena australis)

    PubMed Central

    Eroh, Guy D.; Clayton, Fred C.; Florell, Scott R.; Cassidy, Pamela B.; Chirife, Andrea; Marón, Carina F.; Valenzuela, Luciano O.; Campbell, Michael S.; Seger, Jon; Rowntree, Victoria J.; Leachman, Sancy A.

    2017-01-01

    Southern right whales (SRWs, Eubalena australis) are polymorphic for an X-linked pigmentation pattern known as grey morphism. Most SRWs have completely black skin with white patches on their bellies and occasionally on their backs; these patches remain white as the whale ages. Grey morphs (previously referred to as partial albinos) appear mostly white at birth, with a splattering of rounded black marks; but as the whales age, the white skin gradually changes to a brownish grey color. The cellular and developmental bases of grey morphism are not understood. Here we describe cellular and ultrastructural features of grey-morph skin in relation to that of normal, wild-type skin. Melanocytes were identified histologically and counted, and melanosomes were measured using transmission electron microscopy. Grey-morph skin had fewer melanocytes when compared to wild-type skin, suggesting reduced melanocyte survival, migration, or proliferation in these whales. Grey-morph melanocytes had smaller melanosomes relative to wild-type skin, normal transport of melanosomes to surrounding keratinocytes, and normal localization of melanin granules above the keratinocyte nuclei. These findings indicate that SRW grey-morph pigmentation patterns are caused by reduced numbers of melanocytes in the skin, as well as by reduced amounts of melanin production and/or reduced sizes of mature melanosomes. Grey morphism is distinct from piebaldism and albinism found in other species, which are genetic pigmentation conditions resulting from the local absence of melanocytes, or the inability to synthesize melanin, respectively. PMID:28170433

  8. Cellular and ultrastructural characterization of the grey-morph phenotype in southern right whales (Eubalaena australis).

    PubMed

    Eroh, Guy D; Clayton, Fred C; Florell, Scott R; Cassidy, Pamela B; Chirife, Andrea; Marón, Carina F; Valenzuela, Luciano O; Campbell, Michael S; Seger, Jon; Rowntree, Victoria J; Leachman, Sancy A

    2017-01-01

    Southern right whales (SRWs, Eubalena australis) are polymorphic for an X-linked pigmentation pattern known as grey morphism. Most SRWs have completely black skin with white patches on their bellies and occasionally on their backs; these patches remain white as the whale ages. Grey morphs (previously referred to as partial albinos) appear mostly white at birth, with a splattering of rounded black marks; but as the whales age, the white skin gradually changes to a brownish grey color. The cellular and developmental bases of grey morphism are not understood. Here we describe cellular and ultrastructural features of grey-morph skin in relation to that of normal, wild-type skin. Melanocytes were identified histologically and counted, and melanosomes were measured using transmission electron microscopy. Grey-morph skin had fewer melanocytes when compared to wild-type skin, suggesting reduced melanocyte survival, migration, or proliferation in these whales. Grey-morph melanocytes had smaller melanosomes relative to wild-type skin, normal transport of melanosomes to surrounding keratinocytes, and normal localization of melanin granules above the keratinocyte nuclei. These findings indicate that SRW grey-morph pigmentation patterns are caused by reduced numbers of melanocytes in the skin, as well as by reduced amounts of melanin production and/or reduced sizes of mature melanosomes. Grey morphism is distinct from piebaldism and albinism found in other species, which are genetic pigmentation conditions resulting from the local absence of melanocytes, or the inability to synthesize melanin, respectively.

  9. Comparative linkage mapping of the Grey coat colour gene in horses.

    PubMed

    Pielberg, G; Mikko, S; Sandberg, K; Andersson, L

    2005-10-01

    Grey horses are born coloured, turn progressively grey and often develop melanomas late in life. Grey shows an autosomal dominant inheritance and the locus has previously been mapped to horse chromosome 25 (ECA25), around the TXN gene. We have now developed eight new single nucleotide polymorphisms (SNPs) associated with genes on ECA25 using information on the linear order of genes on human chromosome 9q, as well as the human and mouse coding sequences. These SNPs were mapped in relation to the Grey locus using more than 300 progeny from matings between two Swedish Warmblood grey stallions and non-grey mares. Grey was firmly assigned to an interval with flanking markers NANS and ABCA1. This corresponds to a region of approximately 6.9 Mb on human chromosome 9q. Furthermore, no recombination was observed between Grey, TGFBR1 and TMEFF1, the last two being 1.4 Mb apart in human. There are no obvious candidate genes in this region and none of the genes has been associated with pigmentation disorders or melanoma development, suggesting that the grey phenotype is caused by a mutation in a novel gene.

  10. Diels-Alder Cycloadditions: A MORE Experiment in the Organic Laboratory Including a Diene Identification Exercise Involving NMR Spectroscopy and Molecular Modeling

    ERIC Educational Resources Information Center

    Shaw, Roosevelt; Severin, Ashika; Balfour, Miguel; Nettles, Columbus

    2005-01-01

    Two Diels-Alder reactions are described that are suitable for a MORE (microwave-induced organic reaction enhanced) experiment in the organic chemistry laboratory course. A second experiment in which the splitting patterns of the vinyl protons in the nuclear magnetic resonance (NMR) spectra of two MORE adducts are used in conjunction with molecular…

  11. Illustrating the Utility of X-Ray Crystallography for Structure Elucidation through a Tandem Aldol Condensation/Diels-Alder Reaction Sequence

    ERIC Educational Resources Information Center

    Hoang, Giang T.; Kubo, Tomohiro; Young, Victor G., Jr.; Kautzky, Jacob A.; Wissinger, Jane E.

    2015-01-01

    Two introductory organic chemistry laboratory experiments are described based on the Diels-Alder reaction of 2,3,4,5-tetraphenylcyclopentadienone, which is synthesized prior to or in a one-pot reaction, with styrene. Students are presented with three possible products, the "endo" and "exo" diastereomers and the decarbonylated…

  12. Fast Hetero-Diels-Alder Reactions Using 4-Phenyl-1,2,4-Triazoline-3,5-Dione (PTAD) as the Dienophile

    ERIC Educational Resources Information Center

    Celius, Tevye C.

    2010-01-01

    A hetero-Diels-Alder reaction that proceeds rapidly and only requires a simple filtration to purify the product is presented. The dienophile, 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD), is prepared by the heterogeneous oxidation of 4-phenylurazole by the bromenium ion, Br[superscript +], generated in situ by the oxidation of potassium bromide by…

  13. Synthesis of a Self-Healing Polymer Based on Reversible Diels-Alder Reaction: An Advanced Undergraduate Laboratory at the Interface of Organic Chemistry and Materials Science

    ERIC Educational Resources Information Center

    Weizman, Haim; Nielsen, Christian; Weizman, Or S.; Nemat-Nasser, Sia

    2011-01-01

    This laboratory experiment exposes students to the chemistry of self-healing polymers based on a Diels-Alder reaction. Students accomplish a multistep synthesis of a monomer building block and then polymerize it to form a cross-linked polymer. The healing capability of the polymer is verified by differential scanning calorimetry (DSC) experiments.…

  14. Integration of Computational and Preparative Techniques to Demonstrate Physical Organic Concepts in Synthetic Organic Chemistry: An Example Using Diels-Alder Reaction

    ERIC Educational Resources Information Center

    Palmer, David R. J.

    2004-01-01

    The Diels-Alder reaction is used as an example for showing the integration of computational and preparative techniques, which help in demonstrating the physical organic concepts in synthetic organic chemistry. These experiments show that the students should not accept the computational results without questioning them and in many Diels-Alder…

  15. The Synthesis of "N"-Benzyl-2-Azanorbornene via Aqueous Hetero Diels-Alder Reaction: An Undergraduate Project in Organic Synthesis and Structural Analysis

    ERIC Educational Resources Information Center

    Sauvage, Xavier; Delaude, Lionel

    2008-01-01

    The synthesis of "N"-benzyl-2-azanorbornene via aqueous hetero Diels-Alder reaction of cyclopentadiene and benzyliminium chloride formed in situ from benzylamine hydrochloride and formaldehyde is described. Characterization of the product was achieved by IR and NMR spectroscopies. The spectral data acquired are thoroughly discussed. Numerous…

  16. Transformation of D-(-)-ribose into a natural product-like scaffold via a Lewis acid catalyzed intramolecular hetero-Diels-Alder reaction.

    PubMed

    Messer, Roland; Fuhrer, Cyril A; Häner, Robert

    2007-01-01

    Starting from D-(-)-ribose, a tricyclic natural product-like scaffold suitable for combinatorial derivatization was synthesized via an intramolecular hetero-Diels-Alder reaction. Lithium perchlorate was found to enhance the reaction rate and, at the same time, had a pronounced influence on the chemoselectivity of the reaction. The stereochemical course of the reaction, however, was not influenced by the Lewis acid.

  17. Diels-Alder Synthesis of endo-cis-N-phenylbicyclo[2.2.2]oct-5-en-2,3-dicarboximide

    ERIC Educational Resources Information Center

    Baar, Marsha R.; Wustholz, Kristin

    2005-01-01

    A study investigated the Diels-Alder synthesis of endo-cis-N-phenylbicyclo [2.2.2]oct-5-en-2,3-dicarboximide. The amount of time taken by a reaction between the 1,3-cyclohexadiene and N-phenylmaleimide at room temperature and also whether the desired cycloadduct would precipitate directly from the reaction mixture was examined.

  18. Combination of inverse electron-demand Diels-Alder reaction with highly efficient oxime ligation expands the toolbox of site-selective peptide conjugations.

    PubMed

    Hörner, S; Uth, C; Avrutina, O; Frauendorf, H; Wiessler, M; Kolmar, H

    2015-07-14

    A modular approach combining inverse electron-demand Diels-Alder coupling (DARinv) and oxime ligation expands the toolbox of bioorthogonal peptide chemistry. Applicability of versatile site-specific bifunctional building blocks is demonstrated by generation of defined conjugates comprising linear, cystine-bridged and multi-disulfide functional peptides as well as their conjugation with hybrid silsesquioxane nanoparticles.

  19. First kinetic evidence for the CH/π and π/π solute-solvent interaction of C60 in the Diels-Alder reaction with cyclohexadiene.

    PubMed

    Oshima, Takumi; Mikie, Tsubasa; Ikuma, Naohiko; Yakuma, Hajime

    2012-03-07

    The first CH/π solute-solvent interaction of C(60) was evidenced by the kinetic solvent effects in the Diels-Alder reaction with 1,3-cyclohexadiene based on the evaluation of linear free energy relationship of log k(2) with empirical solvent polarity and basicity parameters, E(T)(30) and D(π), respectively.

  20. A π-electronic covalent organic framework catalyst: π-walls as catalytic beds for Diels-Alder reactions under ambient conditions.

    PubMed

    Wu, Yang; Xu, Hong; Chen, Xiong; Gao, Jia; Jiang, Donglin

    2015-06-25

    We report a strategy for developing π-electronic covalent organic frameworks as heterogeneous catalysts that enable the use of columnar π-walls as catalytic beds to facilitate organic transformations in their one-dimensional open channels. The π-frameworks exhibit outstanding catalytic activity, promote Diels-Alder reactions under ambient conditions and are robust for cycle use.

  1. Formal Alder-ene reaction of a bicyclo[1.1.0]butane in the synthesis of the tricyclic quaternary ammonium core of daphniglaucins

    PubMed Central

    Ueda, Masafumi; Walczak, Maciej A. A.; Wipf, Peter

    2008-01-01

    A tricyclic substructure of the tetracyclic nitrogen core of the daphniglaucins was formed by an oxidative activation of the allyl side chain of a bicyclo[1.1.0]butylmethylamine, a spontaneous intramolecular formal Alder-ene reaction, and a selective cyclization of a triol intermediate. PMID:19129907

  2. Reducing stand densities in immature and mature stands, applegate watershed, southwest Oregon. Forest Service research note

    SciTech Connect

    Main, M.L.; Amaranthus, M.P.

    1996-02-01

    In the study the authors examined conditions following density management treatments in two adjacent but dissimilar stands in Applegate Watershed, Oregon. An immature stand received a unique density reduction treatment retaining both hardwoods and conifers to encourage long-term survival and growth of its coniferous component. The mature stand density reduction treatment focused on removal of the competitive influence from overstocked, surpressed understory trees and maintaining existing large-diameter conifers. Precommercial thinning greatly reduced stand density and increased quadratic mean diameters in the immature stand. In the immature stand the combination of commercial and precommercial thinnings produced a reduced stand density designed to improve overall stand vigor.

  3. Increased microglial catalase activity in multiple sclerosis grey matter.

    PubMed

    Gray, Elizabeth; Kemp, Kevin; Hares, Kelly; Redondo, Julianna; Rice, Claire; Scolding, Neil; Wilkins, Alastair

    2014-04-22

    Chronic demyelination, on-going inflammation, axonal loss and grey matter neuronal injury are likely pathological processes that contribute to disease progression in multiple sclerosis (MS). Although the precise contribution of each process and their aetiological substrates is not fully known, recent evidence has implicated oxidative damage as a major cause of tissue injury in MS. The degree of tissue injury caused by oxidative molecules, such as reactive oxygen species (ROS), is balanced by endogenous anti-oxidant enzymes which detoxify ROS. Understanding endogenous mechanisms which protect the brain against oxidative injury in MS is important, since enhancing anti-oxidant responses is a major therapeutic strategy for preventing irreversible tissue injury in the disease. Our aims were to determine expression and activity levels of the hydrogen peroxide-reducing enzyme catalase in MS grey matter (GM). In MS GM, a catalase enzyme activity was elevated compared to control GM. We measured catalase protein expression by immune dot-blotting and catalase mRNA by a real-time polymerase chain reaction (RT-PCR). Protein analysis studies showed a strong positive correlation between catalase and microglial marker IBA-1 in MS GM. In addition, calibration of catalase mRNA level with reference to the microglial-specific transcript AIF-1 revealed an increase in this transcript in MS. This was reflected by the extent of HLA-DR immunolabeling in MS GM which was significantly elevated compared to control GM. Collectively, these observations provide evidence that microglial catalase activity is elevated in MS grey matter and may be an important endogenous anti-oxidant defence mechanism in MS.

  4. Reactivity of N-Phenyl-1-Aza-2-Cyano-1,3-Butadienes in the Diels-Alder Reaction.

    PubMed

    Sisti, Nicholas J.; Motorina, Irina A.; Tran Huu Dau, Marie-Elise; Riche, Claude; Fowler, Frank W.; Grierson, David S.

    1996-05-31

    It is found that N-phenyl-2-cyano-1-azadiene 4, prepared via a two-step, one-pot, sequence from acrylanilide, undergoes efficient [4 + 2] cycloaddition with a complete range of electron rich, electron poor, and neutral dienophiles under remarkably mild thermal conditions (90-120 degrees C for 20-48 h). Regiospecific formation of the alpha-cycloadduct wherein the dienophile substituent is alpha to nitrogen is observed for vinyl ethers and styrene, whereas the Diels-Alder reactions with methyl acrylate and methyl vinyl ketone (MVK) produce alpha/beta mixtures in which the alpha-cycloadduct is the major regioisomer (approximately 4-5:1). An essentially identical reaction pattern was observed in the Diels-Alder reaction of N-(p-methoxyphenyl)-2-cyano-1-azadiene 18 and the 4-methyl-substituted azadiene 27. For compound 19 derived from cycloaddition of 18 with ethyl vinyl ether, facile conversion to the dihydropyridine 21 through loss of EtOH on brief acid treatment was also noted. The 2,4-cis-disubstitution pattern confirmed by X-ray diffraction for the major cycloadduct 29 isolated from the reaction of 27 with styrene provides evidence for the endo mode of cycloaddition in the Diels-Alder reaction of N-phenyl(aryl)-2-cyano-1-azadienes. Calculation of the frontier orbital energies and coefficients, as well as the transition state geometries for the [4 + 2] cycloaddition of N-phenyl-2-cyano-1-azadiene 4 with methyl vinyl ether, styrene, and MVK were carried out at the RHF AM1 level (MOPAC, Version 5.0). The FMO treatment indicates that the reaction of 4 with methyl vinyl ether occurs under LUMO(diene) control, whereas in contrast, the corresponding cycloaddition with MVK occurs preferably under HOMO(diene) control. A high degree of asynchronicity is observed in the calculated transition states for reaction of 4 with the three representative dienophiles. In all cases the transition states leading to the alpha-cycloadducts are lower in energy than those giving the beta

  5. 24 CFR 203.34 - Credit standing.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Credit standing. 203.34 Section 203.34 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued....34 Credit standing. A mortgagor must have a general credit standing satisfactory to the Commissioner....

  6. 24 CFR 203.34 - Credit standing.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Credit standing. 203.34 Section 203.34 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued....34 Credit standing. A mortgagor must have a general credit standing satisfactory to the Commissioner....

  7. 24 CFR 203.34 - Credit standing.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Credit standing. 203.34 Section 203.34 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued....34 Credit standing. A mortgagor must have a general credit standing satisfactory to the Commissioner....

  8. 24 CFR 206.37 - Credit standing.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Credit standing. 206.37 Section 206... CONVERSION MORTGAGE INSURANCE Eligibility; Endorsement Eligible Mortgagors § 206.37 Credit standing. Each mortgagor must have a general credit standing satisfactory to the Secretary....

  9. 24 CFR 206.37 - Credit standing.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Credit standing. 206.37 Section 206... CONVERSION MORTGAGE INSURANCE Eligibility; Endorsement Eligible Mortgagors § 206.37 Credit standing. Each mortgagor must have a general credit standing satisfactory to the Secretary....

  10. 24 CFR 206.37 - Credit standing.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Credit standing. 206.37 Section 206... CONVERSION MORTGAGE INSURANCE Eligibility; Endorsement Eligible Mortgagors § 206.37 Credit standing. Each mortgagor must have a general credit standing satisfactory to the Secretary....

  11. 24 CFR 206.37 - Credit standing.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Credit standing. 206.37 Section 206... CONVERSION MORTGAGE INSURANCE Eligibility; Endorsement Eligible Mortgagors § 206.37 Credit standing. Each mortgagor must have a general credit standing satisfactory to the Secretary....

  12. 24 CFR 203.34 - Credit standing.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Credit standing. 203.34 Section 203.34 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued....34 Credit standing. A mortgagor must have a general credit standing satisfactory to the Commissioner....

  13. 24 CFR 203.34 - Credit standing.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Credit standing. 203.34 Section 203.34 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued....34 Credit standing. A mortgagor must have a general credit standing satisfactory to the Commissioner....

  14. 24 CFR 206.37 - Credit standing.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Credit standing. 206.37 Section 206... CONVERSION MORTGAGE INSURANCE Eligibility; Endorsement Eligible Mortgagors § 206.37 Credit standing. Each mortgagor must have a general credit standing satisfactory to the Secretary....

  15. The geographical distribution of grey wolves (Canis lupus) in China: a systematic review

    PubMed Central

    WANG, Lu; MA, Ya-Ping; ZHOU, Qi-Jun; ZHANG, Ya-Ping; SAVOLAINEN, Peter; WANG, Guo-Dong

    2016-01-01

    The grey wolf (Canis lupus) is one of the most widely distributed terrestrial mammals, and its distribution and ecology in Europe and North America are largely well described. However, the distribution of grey wolf in southern China is still highly controversial. Several well-known western literatures stated that there are no grey wolves in southern China, while the presence of grey wolf across China has been indicated in A Guide to the Mammals of China, published by Princeton University Press. It is essential to solve this discrepancy since dogs may have originated from grey wolfs in southern China. Therefore, we systematically investigated Chinese literatures about wild animal surveys and identified more than 100 articles and books that included information of the distribution of grey wolves in China. We also surveyed the collections of three Chinese natural museums and found 26 grey wolf skins specimens collected across China. Moreover, we investigated the fossil records of wolf in China and identified 25 archaeological sites with wolf remains including south China. In conclusion, with the comprehensive summary of Chinese literatures, museum specimens and fossil records, we demonstrate that grey wolves does distribute across all parts of the Chinese mainland, including the most southern parts of China. PMID:28105796

  16. Forecasting Performance of Grey Prediction for Education Expenditure and School Enrollment

    ERIC Educational Resources Information Center

    Tang, Hui-Wen Vivian; Yin, Mu-Shang

    2012-01-01

    GM(1,1) and GM(1,1) rolling models derived from grey system theory were estimated using time-series data from projection studies by National Center for Education Statistics (NCES). An out-of-sample forecasting competition between the two grey prediction models and exponential smoothing used by NCES was conducted for education expenditure and…

  17. Vocal Learning in Grey Parrots: A Brief Review of Perception, Production, and Cross-Species Comparisons

    ERIC Educational Resources Information Center

    Pepperberg, Irene M.

    2010-01-01

    This chapter briefly reviews what is known-and what remains to be understood--about Grey parrot vocal learning. I review Greys' physical capacities--issues of auditory perception and production--then discuss how these capacities are used in vocal learning and can be recruited for referential communication with humans. I discuss cross-species…

  18. The geographical distribution of grey wolves (Canis lupus) in China: a systematic review.

    PubMed

    Wang, Lu; Ma, Ya-Ping; Zhou, Qi-Jun; Zhang, Ya-Ping; Savolaimen, Peter; Wang, Guo-Dong

    2016-11-18

    The grey wolf (Canis lupus) is one of the most widely distributed terrestrial mammals, and its distribution and ecology in Europe and North America are largely well described. However, the distribution of grey wolf in southern China is still highly controversial. Several well-known western literatures stated that there are no grey wolves in southern China, while the presence of grey wolf across China has been indicated in A Guide to the Mammals of China, published by Princeton University Press. It is essential to solve this discrepancy since dogs may have originated from grey wolfs in southern China. Therefore, we systematically investigated Chinese literatures about wild animal surveys and identified more than 100 articles and books that included information of the distribution of grey wolves in China. We also surveyed the collections of three Chinese natural museums and found 26 grey wolf skins specimens collected across China. Moreover, we investigated the fossil records of wolf in China and identified 25 archaeological sites with wolf remains including south China. In conclusion, with the comprehensive summary of Chinese literatures, museum specimens and fossil records, we demonstrate that grey wolves does distribute across all parts of the Chinese mainland, including the most southern parts of China.

  19. Asymmetric Lewis acid organocatalysis of the Diels-Alder reaction by a silylated C-H acid.

    PubMed

    Gatzenmeier, Tim; van Gemmeren, Manuel; Xie, Youwei; Höfler, Denis; Leutzsch, Markus; List, Benjamin

    2016-02-26

    Silylium ion equivalents have shown promise as Lewis acid catalysts for a range of important C-C bond-forming reactions. Here we describe chiral C-H acids that upon in situ silylation, generate silylium-carbanion pairs, which are extremely active Lewis acid catalysts for enantioselective Diels-Alder reactions of cinnamates with cyclopentadiene. Enantiomeric ratios of up to 97:3 and diastereomeric ratios of more than 20:1 are observed across a diverse set of substitution patterns with 1 mole percent (mol %) of C-H acid catalyst and 10 mol % of a silylating reagent. The results show promise for broad applications of such C-H acid-derived silylium ion equivalents in asymmetric Lewis acid catalysis.

  20. Three biscembranoids and their monomeric counterpart cembranoid, a biogenetic Diels-Alder precursor, from the soft coral Sarcophyton elegans.

    PubMed

    Bishara, Ashgan; Rudi, Amira; Benayahu, Yehuda; Kashman, Yoel

    2007-12-01

    Two new cembranoids, methyl tetrahydrosarcoate ( 1) and methyl tetrahydroisosarcoate ( 2), were isolated from the soft coral Sarcophyton elegans, collected at Kitangambwe Kenya, together with four biscembranoids, the known nyalolide ( 3) and the unprecedented desacetylnyalolide ( 4), diepoxynyalolide ( 5), and dioxanyalolide ( 6). The structures and relative stereochemistry of the compounds were elucidated by interpretation of MS, 1D NMR, COSY, HSQC, HMBC, and NOESY experiments. Compound 1 is most likely the dienophile affording, by a Diels-Alder reaction, the four biscembranoids. Dioxanyalolide ( 6) possesses antibacterial activity against Escherichia coli at a concentration of 1.25 microg/mL. Methyl tetrahydrosarcoate ( 1) and diepoxynyalolide ( 5) exhibited LC 50 values of 1.5 microM in a brine shrimp bioassay, while desacetylnyalolide ( 4) was only mildly active.

  1. The hetero-Diels-Alder addition of sulfur dioxide: the pseudo-chair conformation of a 4,5-dialkylsultine.

    PubMed

    Markovic, Dean; Roversi, Elena; Scoppelliti, Rosario; Vogel, Pierre; Meana, Rubén; Sordo, José A

    2003-10-17

    Even unsubstituted butadiene adds to sulfur dioxide in the hetero-Diels-Alder mode more rapidly than in the chelotropic mode. The sultine can be observed in equilibrium with the diene and the sulfur dioxide only at low temperature and in the presence of CF(3)COOH. Crystals of 4,5-dialkyl-sultine resulting from the SO(2) addition to 1,2-dimethylidenecyclohexane have been obtained at -100 degrees C and analyzed by X-ray diffraction. Quantum chemical calculations have shown that hyperconjugative interactions within the sulfinyl moiety are responsible for the anomeric effects observed in sultines that prefer pseudo-chair conformations with pseudo-axial Sdbond;O bonds.

  2. Discovery of TNF inhibitors from a DNA-encoded chemical library based on diels-alder cycloaddition.

    PubMed

    Buller, Fabian; Zhang, Yixin; Scheuermann, Jörg; Schäfer, Juliane; Bühlmann, Peter; Neri, Dario

    2009-10-30

    DNA-encoded chemical libraries are promising tools for the discovery of ligands toward protein targets of pharmaceutical relevance. DNA-encoded small molecules can be enriched in affinity-based selections and their unique DNA "barcode" allows the amplification and identification by high-throughput sequencing. We describe selection experiments using a DNA-encoded 4000-compound library generated by Diels-Alder cycloadditions. High-throughput sequencing enabled the identification and relative quantification of library members before and after selection. Sequence enrichment profiles corresponding to the "bar-coded" library members were validated by affinity measurements of single compounds. We were able to affinity mature trypsin inhibitors and identify a series of albumin binders for the conjugation of pharmaceuticals. Furthermore, we discovered a ligand for the antiapoptotic Bcl-xL protein and a class of tumor necrosis factor (TNF) binders that completely inhibited TNF-mediated killing of L-M fibroblasts in vitro.

  3. Diels-Alder Trapping of Photochemically Generated o-Quinodimethane Intermediates: An Alternative Route to Photocured Polymer Film Development

    NASA Technical Reports Server (NTRS)

    Tyson, Daniel S.; Ilhan, Faysal; Meador, Mary Ann B.; Smith, Dee Dee; Scheiman, Daniel A.; Meador, Michael A.

    2004-01-01

    Photolysis of o-methylphenyl ketones generates bis-o-quinodimethane intermediates that can be trapped in situ by dienophiles through Diels-Alder cycloadditions. This well-known photochemical process is applied to a series of six new photoreactive monomers containing bis-(o-methylphenyl ketone) functionalities combined with diacrylate and triacrylate ester monomers for the development of acrylic ester copolymer blends. Irradiation of cyclohexanone solutions of the bis-(o-methylphenyl ketone)s and acrylate esters produce thin polymer films. Solid state 13C NMR data indicated 47- 100% reaction of the bis-(o-methylphenyl ketone)s, depending on experimental conditions, to yield the desired products. DSC and TGA analyses were performed to determine the glass transition temperature, T,, and onset of decomposition, Td, of the resulting polymer films. A statistical Design of Experiments approach was used to obtain a systematic understanding of the effects of experimental variables on the extent of polymerization and the final polymer properties.

  4. Dextran-based self-healing hydrogels formed by reversible diels-alder reaction under physiological conditions.

    PubMed

    Wei, Zhao; Yang, Jian Hai; Du, Xiao Jing; Xu, Feng; Zrinyi, Miklos; Osada, Yoshihito; Li, Fei; Chen, Yong Mei

    2013-09-01

    A dextran-based self-healing hydrogel is prepared by reversible Diels-Alder reaction under physiological conditions. Cytocompatible fulvene-modified dextran as main polymer chains and dichloromaleic-acid-modified poly(ethylene glycol) as cross-linkers are used. Both macro- and microscopic observation as well as the rheological recovery test confirm the self-healing property of the dextran-l-poly(ethylene glycol) hydrogels ("l" means "linked-by"). In addition, scanning electrochemical microscopy is used to qualitatively and quantitatively in situ track the self-healing process of the hydrogel for the first time. It is found that the longitudinal depth of scratch on hydrogel surface almost completely healed at 37 °C after 7 h. This work represents a facile approach for fabrication of polysaccharide self-healing hydrogel, which can be potentially used in several biomedical fields.

  5. Enantioselective Diels-Alder approach to C-3-oxygenated angucyclinones from (SS)-2-(p-tolysulfinyl)-1,4-naphthoquinone.

    PubMed

    Carreño, M C; Urbano, A; Di Vitta, C

    2000-03-03

    Chiral racemic vinylcyclohexenes 2, bearing oxygenated substituents and/or a methyl group at the C-5 position of the cyclohexene ring, were submitted to Diels-Alder reactions with enantiomerically pure (SS)-(2-p-tolylsulfinyl)-1,4-naphthoquinone [(+)-1]. The domino cycloaddition/pyrolytic sulfoxide elimination process led to the formation of enantiomerically enriched angularly tetracyclic quinones anti-6 and syn-7, which were obtained from the kinetic resolution of the racemic diene. In all cases, (SS)-(2-p-tolylsulfinyl)-1,4-naphthoquinone reacted from the less hindered face of the more reactive s-cis conformation, to form products in good enantiomeric excesses. Steric effects and torsional interactions in the corresponding approaches account for the observed pi-facial diastereoselectivities at both partners. The usefulness of this methodology is illustrated with the four-step totally asymmetric synthesis of the C-3-oxygenated angucyclinone derivative (-)-8-deoxytetrangomycin 10 in 26% overall yield and with 50% enantiomeric purity.

  6. Catalytic Effects of Oxide Surfaces on Diels-Alder Cycloaddition between Furan and Methyl Acrylate: A DFT Study

    NASA Astrophysics Data System (ADS)

    Salavati-Fard, Taha; Jenness, Glen; Caratzoulas, Stavros; Doren, Douglas

    Using density functional theory with periodic boundary conditions, we study the catalytic effects of oxide surfaces such as ZrO_2 and HfO_2 on Diels-Alder reaction between furan and methyl acrylate. The cycloadduct can be dehydrated later to produce methyl benzoic which is an important step toward benzoic acid production. The gas-phase and on-surface reaction mechanisms are studied in detail. The surface hydration effects on the reaction mechanism and energy profile are studied as well. Our calculations show that the oxide surfaces catalyze the reaction significantly through the interaction of metal sites with methyl acrylate. The calculations are interpreted by making use of electronic density of states and band structure of the catalyst.

  7. Theoretical study of the regioselectivity of successive 1,3-butadiene Diels-Alder cycloadditions to C{sub 60}

    SciTech Connect

    Sola, M.; Duran, M.; Mestres, J.

    1996-09-18

    The possibility of successive Diels-Alder cycloadditions of 1,3-butadiene to C{sub 60} has been studied theoretically by means of the AM1 semiempirical method. The nine unique possible reaction pathways leading to the experimentally observed T{sub h}-symmetric hexakisadduct have been described, and the most thermodynamically favored has been analyzed in more detail. The enthalpy barrier for the cycloaddition changes from 16.2 kcal/mol in the formation of the monoadduct to 17.8 kcal/mol for the hexakisadduct, increasing slightly with successive attacks. However, once the hexakisadduct is reached, addition of a new 1,3-butadiene has an enthalpy barrier as high as 35.5 kcal/mol, in agreement with the fact that experimentally the heptakisadduct has not yet been observed. 26 refs., 2 figs., 2 tabs.

  8. Diels-Alder functionalized carbon nanotubes for bone tissue engineering: in vitro/in vivo biocompatibility and biodegradability

    NASA Astrophysics Data System (ADS)

    Mata, D.; Amaral, M.; Fernandes, A. J. S.; Colaço, B.; Gama, A.; Paiva, M. C.; Gomes, P. S.; Silva, R. F.; Fernandes, M. H.

    2015-05-01

    The risk-benefit balance for carbon nanotubes (CNTs) dictates their clinical fate. To take a step forward at this crossroad it is compulsory to modulate the CNT in vivo biocompatibility and biodegradability via e.g. chemical functionalization. CNT membranes were functionalised combining a Diels-Alder cycloaddition reaction to generate cyclohexene (-C6H10) followed by a mild oxidisation to yield carboxylic acid groups (-COOH). In vitro proliferation and osteogenic differentiation of human osteoblastic cells were maximized on functionalized CNT membranes (p,f-CNTs). The in vivo subcutaneously implanted materials showed a higher biological reactivity, thus inducing a slighter intense inflammatory response compared to non-functionalized CNT membranes (p-CNTs), but still showing a reduced cytotoxicity profile. Moreover, the in vivo biodegradation of CNTs was superior for p,f-CNT membranes, likely mediated by the oxidation-induced myeloperoxidase (MPO) in neutrophil and macrophage inflammatory milieus. This proves the biodegradability faculty of functionalized CNTs, which potentially avoids long-term tissue accumulation and triggering of acute toxicity. On the whole, the proposed Diels-Alder functionalization accounts for the improved CNT biological response in terms of the biocompatibility and biodegradability profiles. Therefore, CNTs can be considered for use in bone tissue engineering without notable toxicological threats.The risk-benefit balance for carbon nanotubes (CNTs) dictates their clinical fate. To take a step forward at this crossroad it is compulsory to modulate the CNT in vivo biocompatibility and biodegradability via e.g. chemical functionalization. CNT membranes were functionalised combining a Diels-Alder cycloaddition reaction to generate cyclohexene (-C6H10) followed by a mild oxidisation to yield carboxylic acid groups (-COOH). In vitro proliferation and osteogenic differentiation of human osteoblastic cells were maximized on functionalized CNT

  9. Full cell study of Diels Alder poly(phenylene) anion and cation exchange membranes in vanadium redox flow batteries

    SciTech Connect

    Pezeshki, Alan M.; Fujimoto, Cy; Sun, Che -Nan; Mench, Matthew M.; Zawodzinski, Thomas A.; Tang, Z. J.

    2015-11-14

    In this paper, we report on the performance of Diels Alder poly(phenylene) membranes in vanadium redox flow batteries. The membranes were functionalized with quaternary ammonium groups to form an anion exchange membrane (QDAPP) and with sulfonic acid groups to form a cation exchange membrane (SDAPP). Both membrane classes showed similar conductivities in the battery environment, suggesting that the ion conduction mechanism in the material is not strongly affected by the moieties along the polymer backbone. The resistance to vanadium permeation in QDAPP was not improved relative to SDAPP, further suggesting that the polarity of the functional groups do not play a significant role in the membrane materials tested. Both QDAPP and SDAPP outperformed Nafion membranes in cycling tests, with both achieving voltage efficiencies above 85% while maintaining 95% coulombic efficiency while at a current density of 200 mA/cm2.

  10. Regioselective Synthesis of C-3-Functionalized Quinolines via Hetero-Diels-Alder Cycloaddition of Azadienes with Terminal Alkynes.

    PubMed

    Saunthwal, Rakesh K; Patel, Monika; Verma, Akhilesh K

    2016-08-05

    A highly efficient metal and protection-free approach for the regioselective synthesis of C-3-functionalized quinolines from azadienes (in situ generated from 2-aminobenzyl alcohol) and terminal alkynes through [4 + 2] cycloaddition has been developed. An unprecedented reaction of 2-aminobenzyl alcohol with 1,3- and 1,4-diethynylbenzene provided the C-3 tolylquinolines via [4 + 2] HDA and oxidative decarboxylation. The -NH2 group directed mechanistic approach was well supported by the control experiments and deuterium-labeling studies and by isolating the azadiene intermediate. The reactivity and selectivity of unprotected azadiene in metal-free base-assisted hetero-Diels-Alder reaction is exploited to quickly assemble an important class of C-3-functionalized quinolines, which are difficult to access.

  11. Full cell study of Diels Alder poly(phenylene) anion and cation exchange membranes in vanadium redox flow batteries

    DOE PAGES

    Pezeshki, Alan M.; Fujimoto, Cy; Sun, Che -Nan; ...

    2015-11-14

    In this paper, we report on the performance of Diels Alder poly(phenylene) membranes in vanadium redox flow batteries. The membranes were functionalized with quaternary ammonium groups to form an anion exchange membrane (QDAPP) and with sulfonic acid groups to form a cation exchange membrane (SDAPP). Both membrane classes showed similar conductivities in the battery environment, suggesting that the ion conduction mechanism in the material is not strongly affected by the moieties along the polymer backbone. The resistance to vanadium permeation in QDAPP was not improved relative to SDAPP, further suggesting that the polarity of the functional groups do not playmore » a significant role in the membrane materials tested. Both QDAPP and SDAPP outperformed Nafion membranes in cycling tests, with both achieving voltage efficiencies above 85% while maintaining 95% coulombic efficiency while at a current density of 200 mA/cm2.« less

  12. Adoption in eastern grey kangaroos: a consequence of misdirected care?

    PubMed

    King, Wendy J; Forsyth, David M; Coulson, Graeme; Festa-Bianchet, Marco

    2015-01-01

    Adoption is rare in animals and is usually attributed to kin selection. In a 6-year study of eastern grey kangaroos (Macropus giganteus), 11 of 326 juveniles were adopted. We detected eight adoptions by observing behavioural associations and nursing between marked mothers and young and three more by analysing the relatedness of mothers and young using microsatellite DNA. Four adoptions involved reciprocal switches and three were by mothers whose own pouch young were known to subsequently disappear. Adoptive mothers were not closely related to each other or to adoptees but adoptive mothers and young associated as closely as did biological pairs, as measured by half-weight indices. Switch mothers did not associate closely. Maternal age and body condition did not influence the likelihood of adoption but females were more likely to adopt in years with high densities of females with large pouch young. Adoption did not improve juvenile survival. We conclude that adoptions in this wild population were potentially costly and likely caused by misdirected care, suggesting that eastern grey kangaroos may have poorly developed mother-offspring recognition mechanisms.

  13. "Osmetrichia" in the grey brocket deer (Mazama gouazoubira).

    PubMed

    Ajmat, M T; Chamut, S; Black-Decima, P

    1999-12-01

    Osmetrichia have been defined as hairs specialized in the storage of secretions used in olfactory communication between conspecifics (Müller-Schwarze, et al. 1977). These authors found highly specialized osmetrichia in the tarsal gland tufts of black-tailed but not white-tailed deer. Chemical communication appears to be well developed in grey brocket deer: the bucks scent mark by rubbing their foreheads on bushes, and all deer urinate and defecate almost exclusively on dung heaps. Brocket deer also possess tarsal tufts. The purpose of this study was to examine hairs from several glandular areas in this species. Osmetrichia, similar to those found in black tailed deer, were found in tarsal tufts and in interdigital gland hairs; these hairs possessed open scales with deep pockets suitable for holding secretions, in comparison to the flat scales seen on control hairs. Hairs with different morphological characteristics (slightly open scales) were found over the frontal gland. Specialized hairs were not found in the tarsal tufts of one specimen of a related species, the red brocket deer (Mazama americana). The similarities in the hairs of grey brocket and black-tailed deer are remarkable in light of the ecological and behavioral differences between these two species.

  14. Adoption in Eastern Grey Kangaroos: A Consequence of Misdirected Care?

    PubMed Central

    King, Wendy J.; Forsyth, David M.; Coulson, Graeme; Festa-Bianchet, Marco

    2015-01-01

    Adoption is rare in animals and is usually attributed to kin selection. In a 6-year study of eastern grey kangaroos (Macropus giganteus), 11 of 326 juveniles were adopted. We detected eight adoptions by observing behavioural associations and nursing between marked mothers and young and three more by analysing the relatedness of mothers and young using microsatellite DNA. Four adoptions involved reciprocal switches and three were by mothers whose own pouch young were known to subsequently disappear. Adoptive mothers were not closely related to each other or to adoptees but adoptive mothers and young associated as closely as did biological pairs, as measured by half-weight indices. Switch mothers did not associate closely. Maternal age and body condition did not influence the likelihood of adoption but females were more likely to adopt in years with high densities of females with large pouch young. Adoption did not improve juvenile survival. We conclude that adoptions in this wild population were potentially costly and likely caused by misdirected care, suggesting that eastern grey kangaroos may have poorly developed mother-offspring recognition mechanisms. PMID:25970624

  15. Modified Discrete Grey Wolf Optimizer Algorithm for Multilevel Image Thresholding

    PubMed Central

    Sun, Lijuan; Guo, Jian; Xu, Bin; Li, Shujing

    2017-01-01

    The computation of image segmentation has become more complicated with the increasing number of thresholds, and the option and application of the thresholds in image thresholding fields have become an NP problem at the same time. The paper puts forward the modified discrete grey wolf optimizer algorithm (MDGWO), which improves on the optimal solution updating mechanism of the search agent by the weights. Taking Kapur's entropy as the optimized function and based on the discreteness of threshold in image segmentation, the paper firstly discretizes the grey wolf optimizer (GWO) and then proposes a new attack strategy by using the weight coefficient to replace the search formula for optimal solution used in the original algorithm. The experimental results show that MDGWO can search out the optimal thresholds efficiently and precisely, which are very close to the result examined by exhaustive searches. In comparison with the electromagnetism optimization (EMO), the differential evolution (DE), the Artifical Bee Colony (ABC), and the classical GWO, it is concluded that MDGWO has advantages over the latter four in terms of image segmentation quality and objective function values and their stability. PMID:28127305

  16. Grey parrots use inferential reasoning based on acoustic cues alone.

    PubMed

    Schloegl, Christian; Schmidt, Judith; Boeckle, Markus; Weiß, Brigitte M; Kotrschal, Kurt

    2012-10-22

    Our ability to make logical inferences is considered as one of the cornerstones of human intelligence, fuelling investigations of reasoning abilities in non-human animals. Yet, the evidence to date is equivocal, with apes as the prime candidates to possess these skills. For instance, in a two-choice task, apes can identify the location of hidden food if it is indicated by a rattling noise caused by the shaking of a baited container. More importantly, they also use the absence of noise during the shaking of the empty container to infer that this container is not baited. However, since the inaugural report of apes solving this task, to the best of our knowledge, no comparable evidence could be found in any other tested species such as monkeys and dogs. Here, we report the first successful and instantaneous solution of the shaking task through logical inference by a non-ape species, the African grey parrot. Surprisingly, the performance of the birds was sensitive to the shaking movement: they were successful with containers shaken horizontally, but not with vertical shaking resembling parrot head-bobbing. Thus, grey parrots seem to possess ape-like cross-modal reasoning skills, but their reliance on these abilities is influenced by low-level interferences.

  17. [Landscape influence on the Grey Herons colonies distribution].

    PubMed

    Boisteau, Benjamin; Marion, Loïc

    2006-03-01

    We analysed the spatial relationship between the location and the size of the 112 grey heron colonies existing in 1994 in the two refuge areas after their decline of the species in the 19th century in France: South Brittany (Loire-Atlantique and Morbihan), and eastern France (Haute-Saône, Saône-et-Loire, Meurthe-et-Moselle, Vosges). We tested 35 variables describing the hydrographical network surrounding the colonies from a local to a regional scale using a Geographic Information System. The results show that, whatever the scale, the distribution of the breeding colonies was not governed by the same elements of the hydrographical network in the different areas. Two strategies of spatial utilization were observed between the western and the eastern parts of France. Moreover, two quite distinct situations were also distinguished between Morbihan and Loire-Atlantique. This study stresses that the type and the spatial organization of the hydrographical elements, but also of the history of the populations, are important in the distribution of the Grey Heron colonies.

  18. Neocortical grey matter distribution underlying voluntary, flexible vocalizations in chimpanzees

    PubMed Central

    Bianchi, Serena; Reyes, Laura D.; Hopkins, William D.; Taglialatela, Jared P.; Sherwood, Chet C.

    2016-01-01

    Vocal learning is a key property of spoken language, which might also be present in nonhuman primate species, such as chimpanzees (Pan troglodytes), to a limited degree. While understanding the origins of vocal learning in the primate brain may help shed light on the evolution of speech and language, little is still known regarding the neurobiological correlates of vocal flexibility in nonhuman primates. The current study used voxel-based morphometry (VBM) to assess whether the cerebral cortex of captive chimpanzees that learned to voluntarily produce sounds to attract the attention of a human experimenter (attention-getting sounds) differs in grey matter distribution compared to chimpanzees that do not exhibit this behavior. It was found that chimpanzees that produce attention-getting sounds were characterized by increased grey matter in the ventrolateral prefrontal and dorsal premotor cortices. These findings suggest that the evolution of the capacity to flexibly modulate vocal output may be associated with reorganization of regions for motor control, including orofacial movements, in the primate brain. PMID:27703216

  19. Modified Discrete Grey Wolf Optimizer Algorithm for Multilevel Image Thresholding.

    PubMed

    Li, Linguo; Sun, Lijuan; Guo, Jian; Qi, Jin; Xu, Bin; Li, Shujing

    2017-01-01

    The computation of image segmentation has become more complicated with the increasing number of thresholds, and the option and application of the thresholds in image thresholding fields have become an NP problem at the same time. The paper puts forward the modified discrete grey wolf optimizer algorithm (MDGWO), which improves on the optimal solution updating mechanism of the search agent by the weights. Taking Kapur's entropy as the optimized function and based on the discreteness of threshold in image segmentation, the paper firstly discretizes the grey wolf optimizer (GWO) and then proposes a new attack strategy by using the weight coefficient to replace the search formula for optimal solution used in the original algorithm. The experimental results show that MDGWO can search out the optimal thresholds efficiently and precisely, which are very close to the result examined by exhaustive searches. In comparison with the electromagnetism optimization (EMO), the differential evolution (DE), the Artifical Bee Colony (ABC), and the classical GWO, it is concluded that MDGWO has advantages over the latter four in terms of image segmentation quality and objective function values and their stability.

  20. Juvenile Competency to Stand Trial.

    PubMed

    Stepanyan, Sofia T; Sidhu, Shawn S; Bath, Eraka

    2016-01-01

    Competency to stand trial is interpreted as a protected due process right for all defendants and is defined as a defendant's fundamental knowledge and understanding of the criminal charges being filed, roles and procedures within the courtroom, and a general ability to work with the defense counsel. Questions of competency are most often raised by the judge, defense, or the prosecution, and competency evaluations are most often completed by psychiatrists or psychologists with forensic training or work experience. Mental illness, intellectual disability, developmental disorders, and developmental immaturity are the 4 main factors considered in most juvenile competency evaluations.

  1. Solid lipid nanoparticles affect microbial colonization and enzymatic activity throughout the decomposition of alder leaves in freshwater microcosms.

    PubMed

    Sampaio, A C; Mendes, R J; Castro, P G; Silva, A M

    2017-01-01

    Solid lipid nanoparticles (SLNs) are used as carriers for drug delivery, and are high biocompatible and designed to endure in the host organism. Despite its current industrial production is low, many of these substances are available on the market, and much more are in the production pipeline. As a result, many of them will end in aquatic systems raising the question whether they can pose a risk to aquatic biota and the associated ecological processes. Microbial decomposers of plant litter, play a key role in forested streams being responsible for the energy flow between terrestrial and aquatic environments. Here, we investigated the effects of SLNs on alder leaf litter decomposition by aquatic microbes. Alder leaves were immersed in a stream of Northeast Portugal to allow microbial colonization before being exposed in microcosms of two types of SLNs at two concentrations for 42 days. Results showed that rates of leaf decomposition decreased with exposure to SLNs. Bacterial biomass was not inhibited by SLNs, and cultivable fungi densities remained constant (SLN-A) or increased (SLN-C) compared with control microcosms. The type and concentration of SLNs influenced differently the leaf colonization by fungi as well as fungal sporulation rate. These effects were accompanied by changes in the community extraenzymatic profile: the activities of alkaline phosphatase, acidic phosphatase, Naphthol-AS-BI-phosphohydrolase (P cycle) and lipases increased in the SLNs microcosms. This study provided the first evidence of the adverse effects of the release of SLNs to streams on leaf litter decomposition. Those effects seem to depend on the composition and concentration of SLNs, as well on the microbial target group, or enzyme. Thus, prior to massive industrial production of these nanomaterials, some measures should be taken to avoid environmental impact affecting the microbial communities responsible for detritus decomposition.

  2. Effects of surface inactivation, high temperature drying and preservative treatment on surface roughness and colour of alder and beech wood

    NASA Astrophysics Data System (ADS)

    Aydin, Ismail; Colakoglu, Gursel

    2005-10-01

    Although extensive research has been conducted in wood surface quality analysis, a unified approach to surface quality characterisation does not exist. Measurements of the variation in surface roughness and surface colour are used widely for the evaluation of wood surface quality. Colour is a basic visual feature for wood and wood-based products. Colour measurement is one of the quality control tests that should be carried out because the colour deviations are spotted easily by the consumers. On the other hand, a common problem faced by plywood manufacturers is panel delamination, for which a major cause is poor quality glue-bonds resulting from rough veneer. Rotary cut veneers with dimensions of 500 mm × 500 mm × 2 mm manufactured from alder ( Alnus glutinosa subsp. barbata) and beech ( Fagus orientalis Lipsky) logs were used as materials in this study. Veneer sheets were oven-dried in a veneer dryer at 110 °C (normal drying temperature) and 180 °C (high drying temperature) after peeling process. The surfaces of some veneers were then exposed at indoor laboratory conditions to obtain inactive wood surfaces for glue bonds, and some veneers were treated with borax, boric acid and ammonium acetate solutions. After these treatments, surface roughness and colour measurements were made on veneer surfaces. High temperature drying process caused a darkening on the surfaces of alder and beech veneers. Total colour change value (Δ E*) increased linear with increasing exposure time. Among the treatment solutions, ammonium acetate caused the biggest colour change while treatment with borax caused the lowest changes in Δ E* values. Considerable changes in surface roughness after preservative treatment did not occur on veneer surfaces. Generally, no clear changes were obtained or the values mean roughness profile ( Ra) decreased slightly in Ra values after the natural inactivation process.

  3. Elevated mercury concentrations in the feathers of grey-faced petrels (Pterodroma gouldi) in New Zealand.

    PubMed

    Lyver, P O' B; Aldridge, S P; Gormley, A M; Gaw, S; Webb, S; Buxton, R T; Jones, C J

    2017-04-01

    Our objective was to measure the concentrations of Hg, As, Cd, Co, Cr, Cu, Pb, Sb, V and Zn in the body feathers of grey-faced petrel (Pterodroma gouldi), fluttering shearwater (Puffinus gavia), little shearwater (Puffinus assimilis) and common diving petrel (Pelecanoides urinatrix) from breeding colonies in New Zealand between 2006 and 2013. The mean Hg concentration (36.48ppm; SD=9.59) in grey-faced petrel feathers was approximately 8.5 to 14 times that detected in the other three species sampled. We detected no trend or differences in Hg concentrations in grey-faced petrels over the 8years of this study, but Hg concentrations varied between breeding colonies although there was no strong relationship with latitude. The elevated Hg concentrations detected in grey-faced petrels could pose a risk to the breeding performance of grey-faced petrels and the customary harvest of chicks by Māori (New Zealand's indigenous peoples).

  4. Survival and band recovery rates of sympatric grey ducks and mallards in New Zealand

    USGS Publications Warehouse

    Caithness, T.; Williams, M.; Nichols, J.D.

    1991-01-01

    We used band recovery data from grey ducks (Anas superciliosa) and mallards. (A. platyrhynchos) banded sympatrically during 1957-74 to estimate annual survival and recovery rates. Young birds tended to have higher recovery rates and lower survival rates than adults for both species. Both species showed strong evidence of year-to-year variation in annual survival rates. Survival rates of male mallards were higher than those in females, as is typical for this species in North America, but there was no evidence of sex-specific survival differences in grey ducks. Recovery rate estimates for grey ducks were high and were significantly higher than those for mallards. However, survival rates did not differ significantly between the 2 species within any age-sex class. The similar survival rates, when mallard populations were increasing and grey ducks were decreasing, suggest that mallard reproductive rates have been greater than those of grey ducks.

  5. Bioflocculation of grey water for improved energy recovery within decentralized sanitation concepts.

    PubMed

    Hernández Leal, L; Temmink, H; Zeeman, G; Buisman, C J N

    2010-12-01

    Bioflocculation of grey water was tested with a lab-scale membrane bioreactor in order to concentrate the COD. Three concentration factors were tested based on the ratio of sludge retention time (SRT) and hydraulic retention time (HRT): 3, 8 and 12. COD concentration factor was up to 7.1, achieving a final concentration of 7.2 g COD L(-1). Large fractions of suspended COD were recovered in the concentrate (57%, 81% and 82% at SRT/HRT ratios of 3, 8 and 12, respectively) indicating a strong bioflocculation of grey water. A maximum of 11% of COD mineralization of grey water was measured at the longest SRT tested (1 d). The integration of bioflocculation of grey water in decentralized sanitation concepts may increase the overall production of methane by 73%, based on the biogas produced by black water only. Therefore, bioflocculation is a promising grey water pre-treatment step for energy recovery within decentralized sanitation concepts.

  6. Grey Nurse Shark ( Carcharias taurus) Diving Tourism: Tourist Compliance and Shark Behaviour at Fish Rock, Australia

    NASA Astrophysics Data System (ADS)

    Smith, Kirby; Scarr, Mark; Scarpaci, Carol

    2010-11-01

    Humans can dive with critically endangered grey nurse sharks ( Carcharias taurus) along the east coast of Australia. This study investigated both compliance of tourist divers to a code of conduct and legislation and the behaviour of grey nurse sharks in the presence of divers. A total of 25 data collection dives were conducted from December 2008 to January 2009. Grey nurse shark and diver behaviour were documented using 2-min scan samples and continuous observation. The proportion of time spent observing human-shark interactions was 9.4% of total field time and mean human-shark interaction time was 15.0 min. Results were used to gauge the effectiveness of current management practices for the grey nurse shark dive industry at Fish Rock in New South Wales, Australia. Grey nurse shark dive tourists were compliant to stipulations in the code of conduct and legislation (compliance ranged from 88 to 100%). The research detailed factors that may promote compliance in wildlife tourism operations such as the clarity of the stipulations, locality of the target species and diver perceptions of sharks. Results indicated that grey nurse sharks spent the majority of their time milling (85%) followed by active swimming (15%). Milling behaviour significantly decreased in the presence of more than six divers. Distance between sharks and divers, interaction time and number of sharks were not significantly correlated with grey nurse shark school behaviour. Jaw gaping, rapid withdrawal and stiff or jerky movement were the specific behaviours of grey nurse sharks that occurred most frequently and were associated with distance between divers and sharks and the presence of six or more divers. Revision of the number of divers allowed per interaction with a school of grey nurse sharks and further research on the potential impacts that shark-diving tourism may pose to grey nurse sharks is recommended.

  7. Grey nurse shark (Carcharias taurus) diving tourism: Tourist compliance and shark behaviour at Fish Rock, Australia.

    PubMed

    Smith, Kirby; Scarr, Mark; Scarpaci, Carol

    2010-11-01

    Humans can dive with critically endangered grey nurse sharks (Carcharias taurus) along the east coast of Australia. This study investigated both compliance of tourist divers to a code of conduct and legislation and the behaviour of grey nurse sharks in the presence of divers. A total of 25 data collection dives were conducted from December 2008 to January 2009. Grey nurse shark and diver behaviour were documented using 2-min scan samples and continuous observation. The proportion of time spent observing human-shark interactions was 9.4% of total field time and mean human-shark interaction time was 15.0 min. Results were used to gauge the effectiveness of current management practices for the grey nurse shark dive industry at Fish Rock in New South Wales, Australia. Grey nurse shark dive tourists were compliant to stipulations in the code of conduct and legislation (compliance ranged from 88 to 100%). The research detailed factors that may promote compliance in wildlife tourism operations such as the clarity of the stipulations, locality of the target species and diver perceptions of sharks. Results indicated that grey nurse sharks spent the majority of their time milling (85%) followed by active swimming (15%). Milling behaviour significantly decreased in the presence of more than six divers. Distance between sharks and divers, interaction time and number of sharks were not significantly correlated with grey nurse shark school behaviour. Jaw gaping, rapid withdrawal and stiff or jerky movement were the specific behaviours of grey nurse sharks that occurred most frequently and were associated with distance between divers and sharks and the presence of six or more divers. Revision of the number of divers allowed per interaction with a school of grey nurse sharks and further research on the potential impacts that shark-diving tourism may pose to grey nurse sharks is recommended.

  8. Standing alone with prosodic help*

    PubMed Central

    Frazier, Lyn; Clifton, Charles; Carlson, Katy; Harris, Jesse A.

    2013-01-01

    Two partially independent issues are addressed in two auditory rating studies: under what circumstances is a sub-string of a sentence identified as a stand-alone sentence, and under what circumstances do globally ill-formed but ‘locally coherent’ analyses (Tabor, Galantucci, & Richardson., 2004) emerge? A new type of locally coherent structure is established in Experiment 1, where a that-less complement clause is at least temporarily analyzed as a stand-alone sentence when it corresponds to a prosodic phrase. In Experiment 2, reduced relative clause structures like those in Tabor et al. were investigated. As in Experiment 1, the root sentence (mis-)analyses emerged most frequently when the locally coherent clause corresponded to a prosodic phrase. However, a substantial number of locally coherent analyses emerged even without prosodic help, especially in examples with for-datives (which do not grammatically permit a reduced relative clause structure for some speakers). Overall, the results suggest that prosodic grouping of constituents encourages analysis of a sub-string as a root sentence, and raise the question of whether all local coherence structures involve analysis of an utterance-final sub-string as a root sentence. PMID:24729648

  9. The ESS Cryomodule Test Stand

    NASA Astrophysics Data System (ADS)

    Hees, W.; Arnold, P.; Fydrych, J.; Spoelstra, H.; Wang, X. L.; Weisend, J. G., II

    The European Spallation Source (ESS) is an intergovernmental project building a multidisciplinary research laboratory based upon the world's most powerful neutron source to be built in Lund, Sweden. The ESS will use a linear accelerator which will deliver protons with 5 MW of power to the target at 2.0 GeV with a nominal current of 62.5 mA. The superconducting part of the linac consists of around 150 niobium cavities cooled with superfluid helium at 2 K. The majority of these cavities are of the elliptical type. They are grouped in cryomodules that hold 4 cavities each, with beam correction optics located between the cryomodules. A dedicated cryoplant will supply the cryomodules with single phase helium through an external cryogenic distribution line. Each of the 30 cryomodules containing elliptical cavities will undergo their site acceptance tests at the ESS cryomodule test stand in Lund. This test stand will use a dedicated 4.5 K cryoplant and warm sub-atmospheric compression to supply the 2 K helium as well as the 40/50 K shield cooling. A test bunker will accommodate one elliptical cavity cryomodule at a time and provide test capacities during both the installation phase as well as later during operation.

  10. The one-leg standing radiograph

    PubMed Central

    Naratrikun, K.; Kanitnate, S.; Sangkomkamhang, T.

    2016-01-01

    Objectives The purpose of this study was to compare the joint space width between one-leg and both-legs standing radiographs in order to diagnose a primary osteoarthritis of the knee. Methods Digital radiographs of 100 medial osteoarthritic knees in 50 patients were performed. The patients had undergone one-leg standing anteroposterior (AP) views by standing on the affected leg while a both-legs standing AP view was undertaken while standing on both legs. The severity of the osteoarthritis was evaluated using the joint space width and Kellgren-Lawrence (KL) radiographic classification. The t-test was used for statistical analysis. Results The mean medial joint space width found in the one-leg and in the both-legs standing view were measured at 1.8 mm and 2.4 mm, respectively (p < 0.001, 95% CI 0.5 to 0.7). 33%, 47.4% and 23.1% of the knees diagnosed with a KL grade of I, II and III in the both-legs standing views were changed to KL grade II, III and IV in the one-leg standing views, respectively. No changes for KL IV osteoarthritis diagnoses have been found between both- and one-leg standing views. Conclusions One-leg standing radiographs better represent joint space width than both-legs standing radiographs. 32% of both-legs standing radiographs have changed the KL grading to a more severe grade than that in the one-leg standing radiographs. Cite this article: P. Pinsornsak, K. Naratrikun, S. Kanitnate, T. Sangkomkamhang. The one-leg standing radiograph: An improved technique to evaluate the severity of knee osteoarthritis. Bone Joint Res 2016;5:436–441. DOI: 10.1302/2046-3758.59.BJR-2016-0049.R1. PMID:27683299

  11. B(C6F5)3: A New Class of Strong and Bulky Lewis Acid for Exo-Selective Intermolecular Diels-Alder Reactions of Unreactive Acyclic Dienes with α,β-Enals.

    PubMed

    Zhou, Jia-Hui; Jiang, Bing; Meng, Fei-Fan; Xu, Yun-He; Loh, Teck-Peng

    2015-09-18

    Lewis acid B(C6F5)3 catalyzed the Diels-Alder reactions of multisubstituted open-chain dienes and α,β-enals to afford the desired products with high exo-selectivities are reported. The substituent effect of the dienes and dienophiles on the product's stereoselectivity was thoroughly investigated, and it was found that most of the desired exo-Diels-Alder products could be obtained in good yields and with high exo-stereoselectivities.

  12. GENERAL VIEW OF SITE LOOKING SOUTHWEST. JUPITER 'HOP' STAND, FOREGROUND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GENERAL VIEW OF SITE LOOKING SOUTHWEST. JUPITER 'HOP' STAND, FOREGROUND CENTER, REDSTONE TEST STAND FOREGROUND RIGHT, SATURN I C TEST STAND BACKGROUND LEFT. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

  13. Stand by electrical supply source

    SciTech Connect

    Mucsy, E.; Hoos, K.

    1985-06-25

    A stand-by electrical energy source for equipment to be operated with substantially continuous current supply, comprising three components one of which is at least one electric rotary machine, another of which is a flywheel and the third of which is an auxiliary energy source. Planetary gearing is provided, comprising a central shaft on which is mounted a sun gear, a planet gear and a ring gear, each of the three components being connected with a respective one of these gears. Two of the three components are interconnected by a drive with an infinitely variable transmission. In one embodiment, the electric rotary machine is connected to the planet gear, the flywheel is connected to the sun gear and the auxiliary energy source is connected with the ring gear. In another embodiment, the electric rotary machine is connected to the sun gear, the flywheel is connected to the ring gear, and the auxiliary energy source is connected to the planet gear.

  14. A house divided cannot stand

    SciTech Connect

    Gilbert, S.M. )

    1994-01-01

    When it comes to the relationships between electric utilities and public service commissions, utilities would do well to remember the words of Abraham Lincoln -- [open quotes]A house divided against itself cannot stand.[close quotes] For just as distrust, dissension, and division threatened the future of the United States during the Civil War, they threaten the future of utilities today.In an effort to lower their costs and increase their competitive advantage, utility companies are increasingly looking to reinvent cultures, reengineer work processes, and redefine corporate missions, values, and strategies. But unless utilities also rebuild regulatory relations, such efforts are doomed to fail. If this prognosis sounds overly simplistic or melodramatic -- especially as utilities appear to be moving toward an era of reduced regulation -- think again. History shows that regulatory relationships drive a utility's ability to successfully integrate demand-side management (DSM) programs that are often critical to business strategies and goals.

  15. Grey Milky Way extinction from SDSS stellar photometry

    NASA Astrophysics Data System (ADS)

    Gorbikov, Evgeny; Brosch, Noah

    2010-01-01

    We report results concerning the distribution and properties of galactic extinction at high galactic latitudes derived from stellar statistics using the Sloan Digital Sky Survey (SDSS). We use the classical Wolf diagram method to identify regions with extinction, and derive the extinction and the extinction law of the dust using all five SDSS spectral bands. We estimate the distance to the extinguishing medium using simple assumptions about the stellar populations in the line of sight. We report the identification of three extinguishing clouds, each a few tens of pc wide, producing 0.2-0.4 mag of g'-band extinction, located 1-2 kpc away or 0.5-1 kpc above the Galactic plane. All clouds exhibit grey extinction, i.e. almost wavelength independent in the limited spectral range of the SDSS. We discuss the implication of this finding on general astrophysical questions.

  16. Species of Cercospora associated with grey leaf spot of maize.

    PubMed

    Crous, Pedro W; Groenewald, Johannes Z; Groenewald, Marizeth; Caldwell, Pat; Braun, Uwe; Harrington, Thomas C

    2006-01-01

    Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the internal transcribed spacers (ITS1 & ITS2), the 5.8S rRNA gene, elongation factor 1-alpha, histone H3, actin and calmodulin gene regions suggest that Groups I and II are two distinct species. Furthermore, Cercospora zeae-maydis (Group I) can be distinguished from C. zeina sp. nov. (Group II) by its faster growth rate on artificial media, the ability to produce cercosporin, longer conidiophores, and broadly fusiform conidia. A PCR-based test that distinguishes the two species was developed using species-specific primers designed from the histone H3 gene.

  17. Causality in condensates: grey solitons as remnants of BEC formation

    SciTech Connect

    Zurek, Wojciech H

    2008-01-01

    Symmetry breaking during phase transitions can lead to the formation of topological defects (such as vortex lines in superfluids). However, the usually studied BEC's have the shape of a cigar, a geometry that impedes vortex formation, survival, and detection. I show that, in elongated traps, one can expect the formation of 'grey solitons' (long-lived, non-topological 'phase defects') as a result of the same mechanism. Their number will rise approximately in proportion to the transition rate. This steep rise is due to the increasing size of the region of the BEC cigar where the phase of the condensate wavefunction is chosen locally (rather than passed on from the already formed BEC).

  18. Myotonic dystrophy in two European grey wolves (Canis lupus).

    PubMed

    Pákozdy, A; Leschnik, M; Nell, B; Kolm, U S; Virányi, Z; Belényi, B; Molnár, M J; Bilzer, T

    2007-03-01

    Two related European Grey wolves (Canis lupus) with the history of muscle stiffness beginning at 2 weeks of age were examined in this study. Muscle tone and muscle mass were increased in both animals. Muscle stiffness was worsened by stress so that the animals fell into lateral recumbency. Blood chemistry revealed mildly increased serum creatine kinase activity. Abnormal potentials typical of myotonic discharges were recorded by electromyography. Cataract, first-degree atrioventricular (AV) block and inhomogeneous myocardial texture by ultrasound suggested extramuscular involvement. Myopathology demonstrated dystrophic signs in the muscle biopsy specimen. The presumptive diagnosis based on the in vivo findings was myotonic dystrophy. Immunochemistry of the striated muscles revealed focal absence of dystrophin 1 and beta-dystroglycan in both cases. Cardiac and ophthalmologic involvement suggested a disorder very similar to a human form of myotonic dystrophy. This is the first description of myotonic dystrophy in wolves.

  19. Nonrelativistic grey S n -transport radiative-shock solutions

    DOE PAGES

    Ferguson, J. M.; Morel, J. E.; Lowrie, R. B.

    2017-06-01

    We present semi-analytic radiative-shock solutions in which grey Sn-transport is used to model the radiation, and we include both constant cross sections and cross sections that depend on temperature and density. These new solutions solve for a variable Eddington factor (VEF) across the shock domain, which allows for interesting physics not seen before in radiative-shock solutions. Comparisons are made with the grey nonequilibrium-diffusion radiative-shock solutions of Lowrie and Edwards [1], which assumed that the Eddington factor is constant across the shock domain. It is our experience that the local Mach number is monotonic when producing nonequilibrium-diffusion solutions, but that thismore » monotonicity may disappear while integrating the precursor region to produce Sn-transport solutions. For temperature- and density-dependent cross sections we show evidence of a spike in the VEF in the far upstream portion of the radiative-shock precursor. We show evidence of an adaptation zone in the precursor region, adjacent to the embedded hydrodynamic shock, as conjectured by Drake [2, 3], and also confirm his expectation that the precursor temperatures adjacent to the Zel’dovich spike take values that are greater than the downstream post-shock equilibrium temperature. We also show evidence that the radiation energy density can be nonmonotonic under the Zel’dovich spike, which is indicative of anti-diffusive radiation flow as predicted by McClarren and Drake [4]. We compare the angle dependence of the radiation flow for the Sn-transport and nonequilibriumdiffusion radiation solutions, and show that there are considerable differences in the radiation flow between these models across the shock structure. Lastly, we analyze the radiation flow to understand the cause of the adaptation zone, as well as the structure of the Sn-transport radiation-intensity solutions across the shock structure.« less

  20. Nonrelativistic radiative shock solutions with grey Sn-transport

    DOE PAGES

    Ferguson, Jim Michael; Morel, Jim Emanuel; Lowrie, Robert Byron

    2017-02-24

    We present semi-analytic radiative-shock solutions in which grey Sn-transport is used to model the radiation, and we include both constant cross sections and cross sections that depend on temperature and density. These new solutions solve for a variable Eddington factor (VEF) across the shock domain, which allows for interesting physics not seen before in radiative-shock solutions. Comparisons are made with the grey nonequilibrium-diffusion radiative-shock solutions of Lowrie and Edwards [1], which assumed that the Eddington factor is constant across the shock domain. It is our experience that the local Mach number is monotonic when producing nonequilibrium-diffusion solutions, but that thismore » monotonicity may disappear while integrating the precursor region to produce Sn-transport solutions. For temperature- and density-dependent cross sections we show evidence of a spike in the VEF in the far upstream portion of the radiative-shock precursor. We show evidence of an adaptation zone in the precursor region, adjacent to the embedded hydrodynamic shock, as conjectured by Drake [2, 3], and also confirm his expectation that the precursor temperatures adjacent to the Zel’dovich spike take values that are greater than the downstream post-shock equilibrium temperature. We also show evidence that the radiation energy density can be nonmonotonic under the Zel’dovich spike, which is indicative of anti-diffusive radiation flow as predicted by McClarren and Drake [4]. We compare the angle dependence of the radiation flow for the Sn-transport and nonequilibriumdiffusion radiation solutions, and show that there are considerable differences in the radiation flow between these models across the shock structure. Lastly, we analyze the radiation flow to understand the cause of the adaptation zone, as well as the structure of the Sn-transport radiation-intensity solutions across the shock structure.« less

  1. Differential grey matter changes in sensorimotor cortex related to exceptional fine motor skills.

    PubMed

    Stoeckel, M Cornelia; Morgenroth, Farina; Buetefisch, Cathrin M; Seitz, Rüdiger J

    2012-01-01

    Functional changes in sensorimotor representation occur in response to use and lesion throughout life. Emerging evidence suggests that functional changes are paralleled by respective macroscopic structural changes. In the present study we used voxel-based morphometry to investigate sensorimotor cortex in subjects with congenitally malformed upper extremities. We expected increased or decreased grey matter to parallel the enlarged or reduced functional representations we reported previously. More specifically, we expected decreased grey matter values in lateral sensorimotor cortex related to compromised hand function and increased grey matter values in medial sensorimotor cortex due to compensatory foot use. We found a medial cluster of grey matter increase in subjects with frequent, hand-like compensatory foot use. This increase was predominantly seen for lateral premotor, supplementary motor, and motor areas and only marginally involved somatosensory cortex. Contrary to our expectation, subjects with a reduced number of fingers, who had shown shrinkage of the functional hand representation previously, did not show decreased grey matter values within lateral sensorimotor cortex. Our data suggest that functional plastic changes in sensorimotor cortex can be associated with increases in grey matter but may also occur in otherwise macroscopically normal appearing grey matter volumes. Furthermore, macroscopic structural changes in motor and premotor areas may be observed without respective changes in somatosensory cortex.

  2. Multiple sclerosis deep grey matter: the relation between demyelination, neurodegeneration, inflammation and iron.

    PubMed

    Haider, Lukas; Simeonidou, Constantina; Steinberger, Günther; Hametner, Simon; Grigoriadis, Nikolaos; Deretzi, Georgia; Kovacs, Gabor G; Kutzelnigg, Alexandra; Lassmann, Hans; Frischer, Josa M

    2014-12-01

    In multiple sclerosis (MS), diffuse degenerative processes in the deep grey matter have been associated with clinical disabilities. We performed a systematic study in MS deep grey matter with a focus on the incidence and topographical distribution of lesions in relation to white matter and cortex in a total sample of 75 MS autopsy patients and 12 controls. In addition, detailed analyses of inflammation, acute axonal injury, iron deposition and oxidative stress were performed. MS deep grey matter was affected by two different processes: the formation of focal demyelinating lesions and diffuse neurodegeneration. Deep grey matter demyelination was most prominent in the caudate nucleus and hypothalamus and could already be seen in early MS stages. Lesions developed on the background of inflammation. Deep grey matter inflammation was intermediate between low inflammatory cortical lesions and active white matter lesions. Demyelination and neurodegeneration were associated with oxidative injury. Iron was stored primarily within oligodendrocytes and myelin fibres and released upon demyelination. In addition to focal demyelinated plaques, the MS deep grey matter also showed diffuse and global neurodegeneration. This was reflected by a global reduction of neuronal density, the presence of acutely injured axons, and the accumulation of oxidised phospholipids and DNA in neurons, oligodendrocytes and axons. Neurodegeneration was associated with T cell infiltration, expression of inducible nitric oxide synthase in microglia and profound accumulation of iron. Thus, both focal lesions as well as diffuse neurodegeneration in the deep grey matter appeared to contribute to the neurological disabilities of MS patients.

  3. Multiple sclerosis deep grey matter: the relation between demyelination, neurodegeneration, inflammation and iron

    PubMed Central

    Haider, Lukas; Simeonidou, Constantina; Steinberger, Günther; Hametner, Simon; Grigoriadis, Nikolaos; Deretzi, Georgia; Kovacs, Gabor G; Kutzelnigg, Alexandra; Lassmann, Hans; Frischer, Josa M

    2014-01-01

    In multiple sclerosis (MS), diffuse degenerative processes in the deep grey matter have been associated with clinical disabilities. We performed a systematic study in MS deep grey matter with a focus on the incidence and topographical distribution of lesions in relation to white matter and cortex in a total sample of 75 MS autopsy patients and 12 controls. In addition, detailed analyses of inflammation, acute axonal injury, iron deposition and oxidative stress were performed. MS deep grey matter was affected by two different processes: the formation of focal demyelinating lesions and diffuse neurodegeneration. Deep grey matter demyelination was most prominent in the caudate nucleus and hypothalamus and could already be seen in early MS stages. Lesions developed on the background of inflammation. Deep grey matter inflammation was intermediate between low inflammatory cortical lesions and active white matter lesions. Demyelination and neurodegeneration were associated with oxidative injury. Iron was stored primarily within oligodendrocytes and myelin fibres and released upon demyelination. In addition to focal demyelinated plaques, the MS deep grey matter also showed diffuse and global neurodegeneration. This was reflected by a global reduction of neuronal density, the presence of acutely injured axons, and the accumulation of oxidised phospholipids and DNA in neurons, oligodendrocytes and axons. Neurodegeneration was associated with T cell infiltration, expression of inducible nitric oxide synthase in microglia and profound accumulation of iron. Thus, both focal lesions as well as diffuse neurodegeneration in the deep grey matter appeared to contribute to the neurological disabilities of MS patients. PMID:24899728

  4. 40Ar/39Ar ages from the rhyolite of Alder Creek, California: Age of the Cobb Mountain Normal-Polarity Subchron revisited

    NASA Astrophysics Data System (ADS)

    Turrin, Brent D.; Donnelly-Nolan, Julie M.; Carter Hearn, B., Jr.

    1994-03-01

    New 40Ar/39Ar age determinations on sanidine from the rhyolite of Alder Creek, California, indicate a 1.186 ±0.006 Ma age for the Cobb Mountain Normal-Polarity Subchron. The new age is statistically older (α = 0.05) than the previously reported K-Ar age (1.12 ±0.02 Ma) and agrees with the age suggested by the astronomical polarity time scale. Incomplete extraction of radiogenic 40Ar (40Ar*) from the sanidine is the most likely reason for the disparity between the 40Ar/39Ar and K-Ar ages. Because the Cobb Mountain subchron is a worldwide, short-duration event, and because no widely used interlaboratory 40Ar/39Ar standard younger than 27 Ma exists, we propose that sanidine from the rhyolite of Alder Creek be considered for use as a new Quaternary 40Ar/39Ar mineral standard.

  5. Highly Regio- and Stereoselective Diels-Alder Cycloadditions via Two-Step and Multicomponent Reactions Promoted by Infrared Irradiation under Solvent-Free Conditions

    PubMed Central

    Flores-Conde, Maria Ines; Reyes, Leonor; Herrera, Rafael; Rios, Hulme; Vazquez, Miguel A.; Miranda, Rene; Tamariz, Joaquin; Delgado, Francisco

    2012-01-01

    Infrared irradiation promoted the Diels-Alder cycloadditions of exo-2-oxazolidinone dienes 1–3 with the Knoevenagel adducts 4–6, as dienophiles, leading to the synthesis of new 3,5-diphenyltetrahydrobenzo[d]oxazol-2-one derivatives (7, 9, 11 and 13–17), under solvent-free conditions. These cycloadditions were performed with good regio- and stereoselectivity, favoring the para-endo cycloadducts. We also evaluated the one-pot three-component reaction of active methylene compounds 20, benzaldehydes 21 and exo-2-oxazolidinone diene 2 under the same reaction conditions. A cascade Knoevenagel condensation/Diels-Alder cycloaddition reaction was observed, resulting in the final adducts 13–16 in similar yields. These procedures are environmentally benign, because no solvent and no catalyst were employed in these processes. The regioselectivity of these reactions was rationalized by Frontier Molecular Orbital (FMO) calculations. PMID:22489113

  6. 40Ar/39Ar ages from the rhyolite of Alder Creek, California: age of the Cobb Mountain normal-polarity subchron revisited

    USGS Publications Warehouse

    Turrin, B.D.; Donnelly-Nolan, J. M.; Hearn, B.C.

    1994-01-01

    New 40Ar/39Ar age determinations on sanidine from the rhyolite of Alder Creek, California, indicate a 1.186 ?? 0.006 Ma age for the Cobb Mountain Normal-Polarity Subchron. The hew age is statistically older (?? = 0.05) than the previously reported K-Ar age (1.12 ?? 0.02 Ma) and agrees with the age suggested by the astronomical polarity time scale. Incomplete extraction of radiogenic 40Ar (40Ar*) from the sanidine is the most likely reason for the disparity between the 40Ar/39Ar and K-Ar ages. Because the Cobb Mountain subchron is a worldwide, short-duration event, and because no widely used interlaboratory 40Ar/39Ar standard younger than 27 Ma exists, it is proposed that sanidine from the rhyolite of Alder Creek be considered for use as a new Quaternary 40Ar/39Ar mineral standard. -Authors

  7. Origins of the Unfavorable Activation and Reaction Energies of 1-Azadiene Heterocycles Compared to 2-Azadiene Heterocycles in Diels-Alder Reactions.

    PubMed

    Fell, Jason S; Martin, Blanton N; Houk, K N

    2017-02-17

    The reactivities of butadiene, cyclopentadiene, furan, thiophene, pyrrole, and their 1-aza- and 2-aza-derivatives in Diels-Alder reactions with ethylene and fumaronitrile were investigated with density functional theory (M06-2X/6-311G(d,p)). The activation free energies for the Diels-Alder reactions of cyclic 1-azadienes are 10-14 kcal mol(-1) higher than those of cyclic 2-azadienes, and the reaction free energies are 17-20 kcal mol(-1) more endergonic. The distortion/interaction model shows that the increased activation energies of cyclic 1-azadienes originate from increased transition state distortion energies and unfavorable interaction energies, arising from addition to the nitrogen terminus of the C═N bond.

  8. Refrigeration system having standing wave compressor

    DOEpatents

    Lucas, Timothy S.

    1992-01-01

    A compression-evaporation refrigeration system, wherein gaseous compression of the refrigerant is provided by a standing wave compressor. The standing wave compressor is modified so as to provide a separate subcooling system for the refrigerant, so that efficiency losses due to flashing are reduced. Subcooling occurs when heat exchange is provided between the refrigerant and a heat pumping surface, which is exposed to the standing acoustic wave within the standing wave compressor. A variable capacity and variable discharge pressure for the standing wave compressor is provided. A control circuit simultaneously varies the capacity and discharge pressure in response to changing operating conditions, thereby maintaining the minimum discharge pressure needed for condensation to occur at any time. Thus, the power consumption of the standing wave compressor is reduced and system efficiency is improved.

  9. Synthesis of Complex Hexacyclic Compounds via a Tandem Rh(II)-Catalyzed Double-Cyclopropanation/Cope Rearrangement/Diels–Alder Reaction

    PubMed Central

    2015-01-01

    Treatment of (E)-1-(methoxymethylene)-1,2,3,4-tetrahydronaphthalene with styryl diazoacetates in the presence of catalytic amounts of the dirhodium complex Rh2(S-DOSP)4 provides a highly enantioenriched hexacyclic product with 10 new stereogenic centers. The transformation proceeds by a cascade sequence starting with a double cyclopropanation of a benzene ring, followed by a Cope rearrangement of a divinylcyclopropane and then an intramolecular Diels–Alder cycloaddition. PMID:25208337

  10. Remarkably high asymmetric amplification in the chiral lanthanide complex-catalyzed hetero-Diels-Alder reaction: first example of the nonlinear effect in ML3 system

    PubMed

    Furuno; Hanamoto; Sugimoto; Inanaga

    2000-01-01

    [reaction: see text] A remarkably high asymmetric amplification was realized in the Yb[(R)-BNP]3-catalyzed hetero-Diels-Alder reaction as the first example in the metal/chiral ligand 1:3 system. The mechanism may be explained by the autogenetic formation of the enantiopure complex as the most active catalyst. The enantiomer-discriminative formation of homochiral ML3 complexes is quite general within the lanthanide metal ions with similar ionic radii to that of the ytterbium ion.

  11. Synthesis of aza polycyclic compounds derived from pyrrolidine, indolizidine, and indole via intramolecular Diels-Alder cycloadditions of neutral 2-azadienes.

    PubMed

    Palacios, Francisco; Alonso, Concepción; Amezua, Patricia; Rubiales, Gloria

    2002-03-22

    A method for the preparation of novel oxaza and diaza polycyclic 9-oxa-4-azaphenanthrene, 5H-pyrido[2,3-a]pyrrolizine, 5H,6H-pyrido[3,2-g]indolizine, and 5H,6H-indeno[2,1-a]indole is described, based on tandem reactions: aza-Wittig reaction of N-vinylic phosphazenes with functionalized aldehydes and an intramolecular aza-Diels-Alder reaction.

  12. An enantioselective Diels-Alder reaction of 1,2-dihydropyridines with α-acyloxyacroleins catalyzed by a chiral primary ammonium salt.

    PubMed

    Ishihara, Kazuaki; Yamada, Hiroki; Akakura, Matsujiro

    2014-06-18

    The first enantioselective Diels-Alder reaction of 1,2-dihydropyridines with α-acyloxyacroleins catalyzed by a chiral primary ammonium salt has been developed and it offers more efficient routes to key synthetic intermediates of alkaloids, for which the direct preparations were unavailable before. The asymmetric induction can be understood through the optimized geometry of an iminium salt aqua complex derived from the catalyst and the dienophile.

  13. CMS memo OKs use of standing orders.

    PubMed

    2008-12-01

    The Centers for Medicare & Medicaid Services (CMS) has reversed course and clarified the use of standing orders in a manner that is much more favorable to EDs. Initiation of standing orders or protocols no longer requires prior authorization by a physician. Documentation still is required, and it must be entered into the medical record, but it can be entered following implementation of the standing order. Nurses can administer drugs if approved by protocol and if it is within their nursing scope of practice.

  14. Non-Grey Radiation Modeling using Thermal Desktop/Sindaworks TFAWS06-1009

    NASA Technical Reports Server (NTRS)

    Anderson, Kevin R.; Paine, Chris

    2006-01-01

    This paper provides an overview of the non-grey radiation modeling capabilities of Cullimore and Ring's Thermal Desktop(Registered TradeMark) Version 4.8 SindaWorks software. The non-grey radiation analysis theory implemented by Sindaworks and the methodology used by the software are outlined. Representative results from a parametric trade study of a radiation shield comprised of a series of v-grooved shaped deployable panels is used to illustrate the capabilities of the SindaWorks non-grey radiation thermal analysis software using emissivities with temperature and wavelength dependency modeled via a Hagen-Rubens relationship.

  15. An alternative to computing grey-scale mathematical morphological operations and its optical implementation

    NASA Astrophysics Data System (ADS)

    Liang, Feng; Liu, Liren; Wang, Binquan; Wang, Zhijiang

    1994-12-01

    An alternative to the umbra definition on grey-scale mathematical morphology is proposed in this paper, which uses the top-surface set instead of the umbra to represent grey-scale structuring element. This algorithm greatly decreases the neighborhood connections for the binary morphological operation transformed from a grey-scale morphological operation. An optical incoherent correlator architecture with threshold device is developed to carry out the suggested algorithm, while a spatial digital coding method is used to represent input 3D binary data in a 2D arrangement. Experimental results are demonstrated too.

  16. How much crosstalk can be allowed in a stereoscopic system at various grey levels?

    NASA Astrophysics Data System (ADS)

    Shestak, Sergey; Kim, Daesik; Kim, Yongie

    2012-03-01

    We have calculated a perceptual threshold of stereoscopic crosstalk on the basis of mathematical model of human vision sensitivity. Instead of linear model of just noticeable difference (JND) known as Weber's law we applied nonlinear Barten's model. The predicted crosstalk threshold varies with the background luminance. The calculated values of threshold are in a reasonable agreement with known experimental data. We calculated perceptual threshold of crosstalk for various combinations of the applied grey level. This result can be applied for the assessment of grey-to-grey crosstalk compensation. Further computational analysis of the applied model predicts the increase of the displayable image contrast with reduction of the maximum displayable luminance.

  17. Grey-Markov model with state membership degree and its application

    NASA Astrophysics Data System (ADS)

    Ye, Jing; Li, Bingjun; Liu, Fang

    2013-10-01

    In the Grey-Markov forecasting, the extent of a given state that a research object belongs to is expressed as state membership degree. The state membership degree can help compensate for the inaccurate states division and improve the predicted results. Based on the Grey-Markov forecasting analysis, this paper uses the central triangle albino function to calculate the state membership degrees of research objects and determine the state transition probability. Thereby, the new model achieves the improvement of conventional Grey-Markov model. Taking the grain production of Henan Province as an example, the validity and applicability of the improved model are verified.

  18. Standing diagnostic and therapeutic equine abdominal surgery.

    PubMed

    Graham, Sarah; Freeman, David

    2014-04-01

    The widespread use of laparoscopy in equine surgery has increased interest in the standing approach to a wide range of procedures typically regarded as feasible only through a ventral midline incision. Although a commonly cited benefit of standing surgery relates to avoiding costs of general anesthesia and risks associated with it, some procedures and horses are not suitable candidates for standing abdominal procedures. Some procedures, such as nephrectomy, colostomy, and closure of the nephrosplenic space, are not only suitable for standing surgery but are performed more easily and more safely through this approach than with general anesthesia.

  19. Simultaneous analysis of 70 pesticides using HPlc/MS/MS: a comparison of the multiresidue method of Klein and Alder and the QuEChERS method.

    PubMed

    Riedel, Melanie; Speer, Karl; Stuke, Sven; Schmeer, Karl

    2010-01-01

    Since 2003, two new multipesticide residue methods for screening crops for a large number of pesticides, developed by Klein and Alder and Anastassiades et al. (Quick, Easy, Cheap, Effective, Rugged, and Safe; QuEChERS), have been published. Our intention was to compare these two important methods on the basis of their extraction efficiency, reproducibility, ruggedness, ease of use, and speed. In total, 70 pesticides belonging to numerous different substance classes were analyzed at two concentration levels by applying both methods, using five different representative matrixes. In the case of the QuEChERS method, the results of the three sample preparation steps (crude extract, extract after SPE, and extract after SPE and acidification) were compared with each other and with the results obtained with the Klein and Alder method. The extraction efficiencies of the QuEChERS method were far higher, and the sample preparation was much quicker when the last two steps were omitted. In most cases, the extraction efficiencies after the first step were approximately 100%. With extraction efficiencies of mostly less than 70%, the Klein and Alder method did not compare favorably. Some analytes caused problems during evaluation, mostly due to matrix influences.

  20. Decrease of ruminal methane production in Rusitec fermenters through the addition of plant material from rhubarb (Rheum spp.) and alder buckthorn (Frangula alnus).

    PubMed

    García-González, R; González, J S; López, S

    2010-08-01

    Roots of rhubarb (Rheum spp.) and bark of alder buckthorn (Frangula alnus) were tested as feed additives for decreasing ruminal methane production released from anaerobic fermentation of a forage-based diet in a rumen-simulating fermenter (Rusitec). Sixteen fermentation units (vessels) were set up for the experiment lasting 19 d. Treated vessels were supplied with 1g/d of rhubarb or alder buckthorn (4 vessels per plant species); another 4 vessels received 12 microM sodium monensin (positive control), and the remaining 4 vessels were controls (no additive). Upon termination of the experimental period, batch cultures were inoculated with the liquid contents of the vessels for examining in vitro fermentation kinetics of cellulose, starch, barley straw, and the same substrate used in the Rusitec cultures. Monensin induced changes in fermentation in agreement with those reported in the literature, and inocula from those cultures decreased the fermentation rate and total gas produced in the gas kinetics study. Rhubarb decreased methane production, associated with limited changes in the profile of volatile fatty acids throughout the duration of the study, whereas digestibility and total volatile fatty acids production were not affected. Rhubarb inocula did not affect gas production kinetics except for cellulose. Alder buckthorn decreased only methane concentration in fermentation gas, and this effect was not always significant. The use of rhubarb (milled rhizomes of Rheum spp.) in the diets of ruminants may effectively modulate ruminal fermentation by abating methane production, thus potentially involving productive and environmental benefits.

  1. Frictional Properties of Sand Collected from the 1906 Rupture Zone of the San Andreas Fault at Alder Creek, CA}

    NASA Astrophysics Data System (ADS)

    Crawford, R. D.; Cashman, S.; Marone, C.; Carpenter, B.; Baldwin, J.

    2006-12-01

    For the purpose of determining fault frictional properties of unconsolidated late Holocene fluvial sediments, samples were collected from trenches excavated across the 1906 rupture trace of the San Andreas Fault (SAF) at Alder Creek, CA. Two fault perpendicular ~2.5m deep trenches cut into late Holocene fluvial sand and gravel exposed a narrow (<1m) steeply dipping, branching, and anastomosing fault zone. Fault strands are defined by abrupt contacts and 0.5-2.0cm wide deformation bands. Samples of sand were collected several meters from the fault zone and enclosed in airtight bags to retain their original moisture content. We sheared layers of the sand in a servocontrolled, double direct shear testing machine at room temperature. A leveling jig prepared 5 mm thick layers of sand that were sheared between rough forcing blocks (5cm x 5cm nominal contact). Normal stress was constant during shear and varied over the suite of experiments from 75KPa to 900KPa, to a corresponding burial of ~3-40 meters. Shear loading was accomplished via a displacement rate boundary condition, which was set initially at 20μm/s and then subject to step changes to 200 and 2000μm/s for a cumulative total shear displacement of 25mm. Velocity stepping procedures are used to measure the velocity dependence of friction where the friction rate parameter, a-b, is the change in steady state sliding friction normalized by the log of velocity. In fault gouge it has been demonstrated that stable frictional behavior (a-b>0) is associated with pervasive shearing and velocity strengthening, while unstable velocity weakening frictional behavior (a-b<0) has been correlated with localized shear. The a-b values for the Alder Creek sands decrease steadily from 0.11 at 75KPa normal stress to less than 0.005 at 900KPa normal stress. If this rate can be extrapolated, it would imply a transition to velocity weakening at ~1Mpa normal stress or a burial of ~45m. The average measured and calculated steady

  2. Stem Photosynthesis not Pressurized Ventilation is Responsible for Light-enhanced Oxygen Supply to Submerged Roots of Alder (Alnus glutinosa)

    PubMed Central

    ARMSTRONG, WILLIAM; ARMSTRONG, JEAN

    2005-01-01

    • Background and Aims Claims that submerged roots of alder and other wetland trees are aerated by pressurized gas flow generated in the stem by a light-induced thermo-osmosis have seemed inconsistent with root anatomy. Our aim was to seek a verification using physical root–stem models, stem segments with or without artificial roots, and rooted saplings. • Methods Radial O2 loss (ROL) from roots was monitored polarographically as the gas space system of the models, and stems were pressurized artificially. ROL and internal pressurization were also measured when stems were irradiated and the xylem stream was either CO2 enriched or not. Stem photosynthesis and respiration were measured polarographically. Stem and root anatomy were examined by light and fluorescence microscopy. • Key Results Pressurizing the models and stems to ≤10 kPa, values much higher than those reportedly generated by thermo-osmosis, created only a negligible density-induced increase in ROL, but ROL increased rapidly when ambient O2 concentrations were raised. Internal pressures rose by several kPa when shoots were exposed to high light flux and ROL increased substantially, but both were due to O2 accumulation from stem photosynthesis using internally sourced CO2. Increased stem pressures had little effect on O2 transport, which remained largely diffusive. Oxygen flux from stems in high light periods indicated a net C gain by stem photosynthesis. Chloroplasts were abundant in the secondary cortex and secondary phloem, and occurred throughout the secondary xylem rays and medulla of 3-year-old stems. Diurnal patterns of ROL, most marked when light reached submerged portions of the stem, were modified by minor variations in light flux and water level. Low root temperatures also helped improve root aeration. • Conclusions Pressurized gas flow to submerged roots does not occur to any significant degree in alder, but stem photosynthesis, using internally sourced CO2 from respiration and the

  3. Standing on a declining surface reduces transient prolonged standing induced low back pain development.

    PubMed

    Gallagher, Kaitlin M; Callaghan, Jack P

    2016-09-01

    While alternating standing position on a sloped surface has proven successful at reducing low back pain during standing, the purpose of this study was to evaluate standing solely on a declining surface to isolate the influence of the postural change. Seventeen participants performed two 75-min prolonged standing occupational simulations- level ground and declining surface. Fifty-three percent of participants (9/17) were categorized as pain developers during the level ground standing condition. For these same pain developers, their average maximum pain scores were 58% lower during sloped standing. All participants showed greater hip flexion, trunk-to-thigh angle flexion, and posterior translation of the trunk center of gravity when standing on the sloped surface. These postural changes could cause the muscles crossing the hip posteriorly to increase passive stiffness and assist with stabilizing the pelvis. This study stresses the importance of hip kinematics, not just lumbar spine posture, in reducing prolonged standing induced low back pain.

  4. Nitrogen mineralization and gaseous nitrogen losses from waterlogged and drained organic soils in a black alder (Alnus glutinosa (L.) Gaertn.) forest

    NASA Astrophysics Data System (ADS)

    Eickenscheidt, T.; Heinichen, J.; Augustin, J.; Freibauer, A.; Drösler, M.

    2014-06-01

    Black alder (Alnus glutinosa (L.) Gaertn.) forests on peat soils have been reported to be hotspots for high nitrous oxide (N2O) losses. High emissions may be attributed to alternating water tables of peatlands and to the incorporation of high amounts of easily decomposable nitrogen (N) into the ecosystem by symbiotic dinitrogen (N2)-fixation of alder trees. Our study addressed the question to what extent drainage enhances the emissions of N2O from black alder forests and how N turnover processes and physical factors influence the production of N2O and total denitrification. The study was conducted in a drained black alder forest with variable groundwater tables at a southern German fen peatland. Fluxes of N2O were measured using the closed chamber method at two drained sites (D-1 and D-2) and one undrained site (U). Inorganic N contents and net N mineralization rates (NNM) were determined. Additionally a laboratory incubation experiment was carried out to investigate greenhouse gas and N2 fluxes at different temperature and soil moisture conditions. Significantly different inorganic N contents and NNM rates were observed, which however did not result in significantly different N2O fluxes in the field but did in the laboratory experiment. N2O fluxes measured were low for all sites, with total annual emissions of 0.51 ± 0.07 (U), 0.97 ± 0.13 (D-1) and 0.93 ± 0.08 kg N2O-N ha-1 yr-1 (D-2). Only 37% of the spatiotemporal variation in field N2O fluxes could be explained by peat temperature and groundwater level, demonstrating the complex interlinking of the controlling factors for N2O emissions. However, temperature was one of the key variables of N2O fluxes in the incubation experiment conducted. Increasing soil moisture content was found to enhance total denitrification losses during the incubation experiment, whereas N2O fluxes remained constant. At the undrained site, permanently high groundwater level was found to prevent net nitrification, resulting in a

  5. Grey seal (Halichoerus grypus) predation on harbour seals (Phoca vitulina) on the island of Helgoland, Germany

    NASA Astrophysics Data System (ADS)

    van Neer, Abbo; Jensen, Lasse Fast; Siebert, Ursula

    2015-03-01

    The prey spectrum of grey seals has to date been described as largely consisting of different fish, cephalopod and shrimp species. On the German island of Helgoland Düne, where harbour seals (Phoca vitulina) and grey seals (Halichoerus grypus) co-occur, a young male grey seal was observed in 2013 and again in 2014 preying upon young harbour seals. A harbour seal carcass with severe traumatic lesions was retrieved and post-mortem examinations were performed. In the following weeks several carcasses showing similar lesions were found. Sightings of grey seals assumed to be preying on harbour porpoises have increased around the North Sea. Increased competition as well as individualised behaviour could explain the increased number of observations, but former cases of abnormal lesions of marine mammals attributed to for example predation by sharks or mechanical processes should be revisited with regard to the emerging knowledge.

  6. Assignment of the horse grey coat colour gene to ECA25 using whole genome scanning.

    PubMed

    Swinburne, June E; Hopkins, A; Binns, M M

    2002-10-01

    The dominant grey coat colour gene of horses has been mapped using a whole genome scanning approach. Samples from a large half-sibling pedigree of Thoroughbred horses were utilized in order to map the grey coat colour locus, G. Multiplex groups of microsatellite markers were developed and used to efficiently screen the horse genome at a resolution of approximately 22 cM, based on an estimated map length for the horse genome of 2720 cM. The grey gene was assigned to chromosome 25 (ECA25), one of the smaller acrocentric horse chromosomes. Based on the current state of knowledge of conserved synteny and coat colour genetics in other mammalian species, there are no obvious candidate genes for the grey gene in the region.

  7. 21 CFR 203.35 - Standing requests.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Standing requests. 203.35 Section 203.35 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL PRESCRIPTION DRUG MARKETING Samples § 203.35 Standing requests. Manufacturers or authorized distributors...

  8. 20 CFR 368.4 - Concession stands.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Concession stands. 368.4 Section 368.4 Employees' Benefits RAILROAD RETIREMENT BOARD INTERNAL ADMINISTRATION, POLICY AND PROCEDURES PROHIBITION OF CIGARETTE SALES TO MINORS § 368.4 Concession stands. Tobacco products may be sold on property occupied...

  9. 20 CFR 368.4 - Concession stands.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Concession stands. 368.4 Section 368.4 Employees' Benefits RAILROAD RETIREMENT BOARD INTERNAL ADMINISTRATION, POLICY AND PROCEDURES PROHIBITION OF CIGARETTE SALES TO MINORS § 368.4 Concession stands. Tobacco products may be sold on property occupied...

  10. 20 CFR 368.4 - Concession stands.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Concession stands. 368.4 Section 368.4 Employees' Benefits RAILROAD RETIREMENT BOARD INTERNAL ADMINISTRATION, POLICY AND PROCEDURES PROHIBITION OF CIGARETTE SALES TO MINORS § 368.4 Concession stands. Tobacco products may be sold on property occupied...

  11. Creating a stand-alone fundraising foundation.

    PubMed

    Dillingham, Walter J; Weiss, Leigh H; Lawson, John M

    2012-10-01

    When considering a stand-alone fundraising foundation, healthcare organizations should: Review the costs and benefits of starting a separate stand-alone foundation. Perform a competitive analysis to see which hospitals use them. Work with a team of legal, development, and investment advisory experts who can help map out a plan. Review governance requirements. Develop an investment policy statement.

  12. 20 CFR 368.4 - Concession stands.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Concession stands. 368.4 Section 368.4 Employees' Benefits RAILROAD RETIREMENT BOARD INTERNAL ADMINISTRATION, POLICY AND PROCEDURES PROHIBITION OF CIGARETTE SALES TO MINORS § 368.4 Concession stands. Tobacco products may be sold on property occupied...

  13. 20 CFR 368.4 - Concession stands.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Concession stands. 368.4 Section 368.4 Employees' Benefits RAILROAD RETIREMENT BOARD INTERNAL ADMINISTRATION, POLICY AND PROCEDURES PROHIBITION OF CIGARETTE SALES TO MINORS § 368.4 Concession stands. Tobacco products may be sold on property occupied...

  14. 9. WEST SIDE, TEST STAND AND SUPERSTRUCTURE. TEST STAND 1B ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. WEST SIDE, TEST STAND AND SUPERSTRUCTURE. TEST STAND 1-B IN DISTANCE. Looking east. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  15. Renal lesions in Baltic grey seals (Halichoerus grypus) and ringed seals (Phoca hispida botnica).

    PubMed

    Bergman, A; Bergstrand, A; Bignert, A

    2001-11-01

    A severe reduction in the populations of grey and ringed seals in the Baltic occurred during the 1960s and 1970s. Adult animals showed (and still show) a series of lesions inter alia in the female reproductive organs, intestines, integument, kidneys, adrenals, and skulls (the Baltic seal disease complex). The morphology and prevalence of light microscopic changes in the kidneys of 76 grey seals and 29 ringed seals collected in the Baltic proper and the Gulf of Bothnia during 1977-1996 are presented in this report. Specific changes in the glomeruli were diffuse thickening of the capillary walls and the presence of large, rounded, hyaline bodies in the capillary or capsular walls. Specific changes in the distal convoluted tubules and the collecting ducts included focal replacement of the normal epithelium by multilayered cell proliferations. The prevalence and extent of the changes were age-related and thus correlated with the time of exposure to environmental toxicants. The lesions were more conspicuous in Baltic grey seals than in Baltic ringed seals. Similar findings were recorded in 5 grey seals from Swedish zoological gardens. These animals had been fed Baltic fish for most of their lives. Electron microscopy was performed on 5 of the Baltic grey seals and on one of the grey seals from zoological gardens. Electron microscopy results mainly based on findings in one of the Baltic grey seals, included mesangial inter-position in the glomerular capillary walls and the characteristics of intercalated cells in cell proliferations in the distal parts of the nephrons. Eleven grey seals from the Scottish coast and 23 ringed seals from Svalbard served as reference material. None of the reference seals showed the specific lesions described above. The authors propose that organochlorine pollution of the Baltic environment is a factor in the cause of these kidney changes.

  16. The Role of Google Scholar in Evidence Reviews and Its Applicability to Grey Literature Searching

    PubMed Central

    Haddaway, Neal Robert; Collins, Alexandra Mary; Coughlin, Deborah; Kirk, Stuart

    2015-01-01

    Google Scholar (GS), a commonly used web-based academic search engine, catalogues between 2 and 100 million records of both academic and grey literature (articles not formally published by commercial academic publishers). Google Scholar collates results from across the internet and is free to use. As a result it has received considerable attention as a method for searching for literature, particularly in searches for grey literature, as required by systematic reviews. The reliance on GS as a standalone resource has been greatly debated, however, and its efficacy in grey literature searching has not yet been investigated. Using systematic review case studies from environmental science, we investigated the utility of GS in systematic reviews and in searches for grey literature. Our findings show that GS results contain moderate amounts of grey literature, with the majority found on average at page 80. We also found that, when searched for specifically, the majority of literature identified using Web of Science was also found using GS. However, our findings showed moderate/poor overlap in results when similar search strings were used in Web of Science and GS (10–67%), and that GS missed some important literature in five of six case studies. Furthermore, a general GS search failed to find any grey literature from a case study that involved manual searching of organisations’ websites. If used in systematic reviews for grey literature, we recommend that searches of article titles focus on the first 200 to 300 results. We conclude that whilst Google Scholar can find much grey literature and specific, known studies, it should not be used alone for systematic review searches. Rather, it forms a powerful addition to other traditional search methods. In addition, we advocate the use of tools to transparently document and catalogue GS search results to maintain high levels of transparency and the ability to be updated, critical to systematic reviews. PMID:26379270

  17. Vocal learning in Grey parrots: A brief review of perception, production, and cross-species comparisons.

    PubMed

    Pepperberg, Irene M

    2010-10-01

    This chapter briefly reviews what is known-and what remains to be understood-about Grey parrot vocal learning. I review Greys' physical capacities-issues of auditory perception and production-then discuss how these capacities are used in vocal learning and can be recruited for referential communication with humans. I discuss cross-species comparisons where applicable and conclude with a description of recent research that integrates issues of reference, production and perception.

  18. The Role of Google Scholar in Evidence Reviews and Its Applicability to Grey Literature Searching.

    PubMed

    Haddaway, Neal Robert; Collins, Alexandra Mary; Coughlin, Deborah; Kirk, Stuart

    2015-01-01

    Google Scholar (GS), a commonly used web-based academic search engine, catalogues between 2 and 100 million records of both academic and grey literature (articles not formally published by commercial academic publishers). Google Scholar collates results from across the internet and is free to use. As a result it has received considerable attention as a method for searching for literature, particularly in searches for grey literature, as required by systematic reviews. The reliance on GS as a standalone resource has been greatly debated, however, and its efficacy in grey literature searching has not yet been investigated. Using systematic review case studies from environmental science, we investigated the utility of GS in systematic reviews and in searches for grey literature. Our findings show that GS results contain moderate amounts of grey literature, with the majority found on average at page 80. We also found that, when searched for specifically, the majority of literature identified using Web of Science was also found using GS. However, our findings showed moderate/poor overlap in results when similar search strings were used in Web of Science and GS (10-67%), and that GS missed some important literature in five of six case studies. Furthermore, a general GS search failed to find any grey literature from a case study that involved manual searching of organisations' websites. If used in systematic reviews for grey literature, we recommend that searches of article titles focus on the first 200 to 300 results. We conclude that whilst Google Scholar can find much grey literature and specific, known studies, it should not be used alone for systematic review searches. Rather, it forms a powerful addition to other traditional search methods. In addition, we advocate the use of tools to transparently document and catalogue GS search results to maintain high levels of transparency and the ability to be updated, critical to systematic reviews.

  19. Self-healable interfaces based on thermo-reversible Diels-Alder reactions in carbon fiber reinforced composites.

    PubMed

    Zhang, W; Duchet, J; Gérard, J F

    2014-09-15

    Thermo-reversible Diels-Alder (DA) bonds formed between maleimide and furan groups have been used to generate an interphase between carbon fiber surface and an epoxy matrix leading to the ability of interfacial self-healing in carbon:epoxy composite materials. The maleimide groups were grafted on an untreated T700 carbon fiber from a three step surface treatment: (i) nitric acid oxidization, (ii) tetraethylenepentamine amination, and (iii) bismaleimide grafting. The furan groups were introduced in the reactive epoxy system from furfuryl glycidyl ether. The interface between untreated carbon fiber and epoxy matrix was considered as a reference. The interfacial shear strength (IFSS) was evaluated by single fiber micro-debonding test. The debonding force was shown to have a linear dependence with embedded length. The highest healing efficiency calculated from the debonding force was found to be about 82% more compared to the value for the reference interface. All the interphases designed with reversible DA bonds have a repeatable self-healing ability. As after the fourth healing, they can recover a relatively high healing efficiency (58% for the interphase formed by T700-BMI which is oxidized for 60 min during the first treatment step).

  20. Diels-Alder derivatization for sensitive detection and characterization of conjugated linoleic acids using LC/ESI-MS/MS.

    PubMed

    Higashi, Tatsuya; Takekawa, Mioko; Min, Jun Zhe; Toyo'oka, Toshimasa

    2012-04-01

    The utility of Diels-Alder derivatization with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) for liquid chromatography/electrospray ionization tandem mass spectrometry of conjugated linoleic acids (CLAs) was examined. PTAD rapidly reacted with the CLAs, and the resulting derivatives were highly responsive in electrospray ionization mass spectrometry operating in the positive-ion mode. The derivatives produced characteristic product ions during tandem mass spectrometry, which enabled the sensitive detection [limit of detection 18 fmol (signal-to-noise ratio of 5)] and the identification of the conjugated diene position. The PTAD derivatization also significantly increased the reversed-phase liquid chromatography separation selectivity for the most biologically active CLA isomers: cis-9,trans-11-CLA and trans-10,cis-12-CLA. The PTAD derivatization was applied to analyses of food and biological samples; the major CLAs in milk and beef fat samples were successfully identified, and trace amounts of CLAs in human saliva were detected with a simple pretreatment and short analysis time.

  1. Spiroketals of Pestalotiopsis fici provide evidence for a biosynthetic hypothesis involving diversified Diels-Alder reaction cascades.

    PubMed

    Liu, Ling; Li, Yan; Li, Li; Cao, Ya; Guo, Liangdong; Liu, Gang; Che, Yongsheng

    2013-04-05

    Chloropestolides B-G (1-6), six new metabolites featuring the chlorinated spiro[benzo[d][1,3]dioxine-2,7'-bicyclo[2.2.2]octane]-4,8'-dione (1-3) and spiro[benzo[d][1,3]dioxine-2,1'-naphthalene]-2',4-dione (4-6) skeletons, and their putative biosynthetic precursor dechloromaldoxin (7) were isolated from the scale-up fermentation cultures of the plant endophytic fungus Pestalotiopsis fici . The structures of 1-7 were determined mainly by NMR experiments. The absolute configurations of 1-3 were deduced by analogy to the previously isolated metabolites from the same fungus (9 and 13-18), whereas those of 4, 5, and 7 were assigned by electronic circular dichroism (ECD) calculations. Structurally, the spiroketal skeletons found in 1-3 and 4-6 could be derived from 2,6-dihydroxy-4-methylbenzoic acid with chlorinated bicyclo[2.2.2]oct-2-en-5-one and 4a,5,8,8a-tetrahydronaphthalen-2(1H)-one, respectively. Biogenetically, compounds 1-6 were derived from the same Diels-Alder precursors as the previously isolated 9 and 12-18. In addition, compounds 2 and 3 were proposed as the biosynthetic intermediates of 17 and 16, respectively. Compound 1 was cytotoxic to three human tumor cell lines.

  2. Face-selective Diels-Alder reactions between unsymmetrical cyclohexadienes and symmetric trans-dienophile: an experimental and computational investigation.

    PubMed

    Lahiri, Saswati; Yadav, Somnath; Banerjee, Srirupa; Patil, Mahendra P; Sunoj, Raghavan B

    2008-01-18

    A combined experimental and theoretical study of the Diels-Alder reactions between 2-trimethylsiloxy-1,3-cyclohexadienes (2-11) and (E)-1,4-diphenylbut-2-ene-1,4-dione (1) is reported. Two diastereomeric products, 5-endo-6-exo- (nx) and 5-exo-6-endo- (xn) dibenzoyl derivatives, are possible with symmetric trans-dienophile (1). While in many cases 5-endo-6-exo product is preferred over the corresponding 5-exo-6-endo product, the product ratio nx:xn is found to vary with the position of substituents on the diene. The density functional theory studies with the mPW1PW91/6-31G* as well as the B3LYP/6-31G* levels reveal that the electrostatic repulsion between the oxygen lone pairs on the diene and the dienophile is critical to the observed product selectivities. The optimized transition state geometries though appeared to involve secondary orbital interactions, careful examination of the frontier Kohn-Sham orbitals as well as calculations with the natural bond orbital (NBO) analyses confirm the absence of SOI in these transition states. In the case of methyl-substituted dienes, a cumulative effect of steric and electrostatic interactions between the diene and the dienophile is found to be the controlling element toward the observed selectivity.

  3. Surface patterning with natural and synthetic polymers via an inverse electron demand Diels-Alder reaction employing microcontact chemistry.

    PubMed

    Roling, Oliver; Mardyukov, Artur; Lamping, Sebastian; Vonhören, Benjamin; Rinnen, Stefan; Arlinghaus, Heinrich F; Studer, Armido; Ravoo, Bart Jan

    2014-10-21

    Bioorthogonal ligation methods are the focus of current research due to their versatile applications in biotechnology and materials science for post-functionalization and immobilization of biomolecules. Recently, inverse electron demand Diels-Alder (iEDDA) reactions employing 1,2,4,5-tetrazines as electron deficient dienes emerged as powerful tools in this field. We adapted iEDDA in microcontact chemistry (μCC) in order to create enhanced surface functions. μCC is a straightforward soft-lithography technique which enables fast and large area patterning with high pattern resolutions. In this work, tetrazine functionalized surfaces were reacted with carbohydrates conjugated with norbornene or cyclooctyne acting as strained electron rich dienophiles employing μCC. It was possible to create monofunctional as well as bifunctional substrates which were specifically addressable by proteins. Furthermore we structured glass supported alkene terminated self-assembled monolayers with a tetrazine conjugated atom transfer radical polymerization (ATRP) initiator enabling surface grafted polymerizations of poly(methylacrylate) brushes. The success of the surface initiated iEDDA via μCC as well as the functionalization with natural and synthetic polymers was verified via fluorescence and optical microscopy, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), atomic force microscopy (AFM) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR).

  4. Alder, Nitrogen, and Lake Ecology: Terrestrial-Aquatic Linkages in the Postglacial History of Lone Spruce Pond, Southwestern Alaska

    PubMed Central

    Axford, Yarrow; Kaufman, Darrell S.

    2017-01-01

    Diatoms, combined with a multiproxy study of lake sediments (organic matter, N, δ15N, δ13C, biogenic silica, grain size, Cladocera and chironomids, Alnus pollen) from Lone Spruce Pond, Alaska detail the late-glacial to Holocene history of the lake and its response to regional climate and landscape change over the last 14.5 cal ka BP. We show that the immigration of alder (Alnus viridis) in the early Holocene marks the rise of available reactive nitrogen (Nr) in the lake as well as the establishment of a primarily planktonic diatom community. The later establishment of diatom Discostella stelligera is coupled to a rise of sedimentary δ15N, indicating diminished competition for this nutrient. This terrestrial-aquatic linkage demonstrates how profoundly vegetation may affect soil geochemistry, lake development, and lake ecology over millennial timescales. Furthermore, the response of the diatom community to strengthened stratification and N levels in the past confirms the sensitivity of planktonic diatom communities to changing thermal and nutrient regimes. These past ecosystem dynamics serve as an analogue for the nature of threshold-type ecological responses to current climate change and atmospheric nitrogen (Nr) deposition, but also for the larger changes we should anticipate under future climate, pollution, and vegetation succession scenarios in high-latitude and high-elevation regions. PMID:28076393

  5. N-(furfural) chitosan hydrogels based on Diels-Alder cycloadditions and application as microspheres for controlled drug release.

    PubMed

    Montiel-Herrera, Marcelino; Gandini, Alessandro; Goycoolea, Francisco M; Jacobsen, Neil E; Lizardi-Mendoza, Jaime; Recillas-Mota, Maricarmen; Argüelles-Monal, Waldo M

    2015-09-05

    In this study, chitosan was chemically modified by reductive amination in a two-step process. The synthesis of N-(furfural) chitosan (FC) was confirmed by FT-IR and (1)H NMR analysis, and the degrees of substitution were estimated as 8.3 and 23.8%. The cross-linkable system of bismaleimide (BM) and FC shows that FC shared properties of furan-maleimide chemistry. This system produced non-reversible hydrogel networks by Diels-Alder cycloadditions at 85 °C. The system composed of BM and FC (23.8% substitution) generated stronger hydrogel networks than those of FC with an 8.3% degree of substitution. Moreover, the FC-BM system was able to produce hydrogel microspheres. Environmental scanning electron microscopy revealed the surface of the microspheres to be non-porous with small protuberances. In water, the microspheres swelled, increasing their volume by 30%. Finally, microspheres loaded with methylene blue were able to release the dye gradually, obeying second-order kinetics for times less than 600 min. This behavior suggests that diffusion is governed by the relaxation of polymer chains in the swelled state, thus facilitating drug release outside the microspheres.

  6. Integrated DEA models and grey system theory to evaluate past-to-future performance: a case of Indian electricity industry.

    PubMed

    Wang, Chia-Nan; Nguyen, Nhu-Ty; Tran, Thanh-Tuyen

    2015-01-01

    The growth of economy and population together with the higher demand in energy has created many concerns for the Indian electricity industry whose capacity is at 211 gigawatts mostly in coal-fired plants. Due to insufficient fuel supply, India suffers from a shortage of electricity generation, leading to rolling blackouts; thus, performance evaluation and ranking the industry turn into significant issues. By this study, we expect to evaluate the rankings of these companies under control of the Ministry of Power. Also, this research would like to test if there are any significant differences between the two DEA models: Malmquist nonradial and Malmquist radial. Then, one advance model of MPI would be chosen to see these companies' performance in recent years and next few years by using forecasting results of Grey system theory. Totally, the realistic data 14 are considered to be in this evaluation after the strict selection from the whole industry. The results found that all companies have not shown many abrupt changes on their scores, and it is always not consistently good or consistently standing out, which demonstrated the high applicable usability of the integrated methods. This integrated numerical research gives a better "past-present-future" insights into performance evaluation in Indian electricity industry.

  7. Integrated DEA Models and Grey System Theory to Evaluate Past-to-Future Performance: A Case of Indian Electricity Industry

    PubMed Central

    Wang, Chia-Nan; Tran, Thanh-Tuyen

    2015-01-01

    The growth of economy and population together with the higher demand in energy has created many concerns for the Indian electricity industry whose capacity is at 211 gigawatts mostly in coal-fired plants. Due to insufficient fuel supply, India suffers from a shortage of electricity generation, leading to rolling blackouts; thus, performance evaluation and ranking the industry turn into significant issues. By this study, we expect to evaluate the rankings of these companies under control of the Ministry of Power. Also, this research would like to test if there are any significant differences between the two DEA models: Malmquist nonradial and Malmquist radial. Then, one advance model of MPI would be chosen to see these companies' performance in recent years and next few years by using forecasting results of Grey system theory. Totally, the realistic data 14 are considered to be in this evaluation after the strict selection from the whole industry. The results found that all companies have not shown many abrupt changes on their scores, and it is always not consistently good or consistently standing out, which demonstrated the high applicable usability of the integrated methods. This integrated numerical research gives a better “past-present-future” insights into performance evaluation in Indian electricity industry. PMID:25821854

  8. Transcriptome analysis of grey mullet (Mugil cephalus) after challenge with Lactococcus garvieae.

    PubMed

    Byadgi, Omkar; Chen, Yao-Chung; Barnes, Andrew C; Tsai, Ming-An; Wang, Pei-Chyi; Chen, Shih-Chu

    2016-11-01

    Grey mullet (Mugil cephalus) is an economically important fish species in Taiwan mariculture industry. Moreover, grey mullet are common hosts of a bacterial infection by Lactococcus garvieae. However, until now the information related to the immune system of grey mullet is unclear. Therefore, to understand the molecular basis underlying the host immune response to L. garvieae infection, Illumina HiSeq™ 2000 was used to analyse the head kidney and spleen transcriptome of infected grey mullet. De novo assembly of paired-end reads yielded 55,203 unigenes. Comparative analysis of the expression profiles between bacterial challenge fish and control fish identified a total of 7192 from head kidney and 7280 in spleen differentially expressed genes (P < 0.05), including 4211 upregulated genes and 2981 downregulated genes in head kidney, while in spleen 3598 genes were upregulated and 3682 downregulated. A significant enrichment analysis of these differentially expressed genes (DEG) in spleen and head kidney revealed major immune-related pathways, including complement and coagulation cascades, Toll-like receptor signalling, and antigen processing and presentation. Moreover, selected DEGs were validated using qPCR. Altogether, the results obtained on immune-related genes may allow for a better understanding of immunity in grey mullet to Lactococcus garvieae, carrying out detailed functional analysis of these genes and developing strategies for efficient immune protection against infections in grey mullet.

  9. Technique of Order Preference by Similarity for Multiple Attribute Decision Making Based on Grey Members

    NASA Astrophysics Data System (ADS)

    Xu, Jiuping; Sasaki, Masato

    The aim of this paper is to extend the technique of order preference by similarity to ideal and anti-ideal alternative to the Grey system. In general, multi-attribute problems in real-life situation have uncertain and imprecise data while Grey system theory is to deal with a linguistic decision process to solve the decision-making problems under uncertainty environment. In this paper, the rating of each alternative and the weight of each criterion are described by linguistic terms that can be expressed in Grey numbers. Further, vertex method is proposed to calculate the distance between Grey numbers. According to the concept of the technique of order preference by similarity to ideal and anti-ideal alternative, a closeness coefficient is defined to determine the ranking order of all alternatives by calculating the distances to both the Grey ideal solution (GIS) and Grey anti-ideal solution (GAIS) simultaneously. Finally, an example is shown to highlight the procedure of the proposed method.

  10. Exposing the grey seal as a major predator of harbour porpoises

    PubMed Central

    Leopold, Mardik F.; Begeman, Lineke; van Bleijswijk, Judith D. L.; IJsseldijk, Lonneke L.; Witte, Harry J.; Gröne, Andrea

    2015-01-01

    Harbour porpoises (Phocoena phocoena) stranding in large numbers around the southern North Sea with fatal, sharp-edged mutilations have spurred controversy among scientists, the fishing industry and conservationists, whose views about the likely cause differ. The recent detection of grey seal (Halichoerus grypus) DNA in bite marks on three mutilated harbour porpoises, as well as direct observations of grey seal attacks on porpoises, have identified this seal species as a probable cause. Bite mark characteristics were assessed in a retrospective analysis of photographs of dead harbour porpoises that stranded between 2003 and 2013 (n = 1081) on the Dutch coastline. There were 271 animals that were sufficiently fresh to allow macroscopic assessment of grey seal-associated wounds with certainty. In 25% of these, bite and claw marks were identified that were consistent with the marks found on animals that had tested positive for grey seal DNA. Affected animals were mostly healthy juveniles that had a thick blubber layer and had recently fed. We conclude that the majority of the mutilated harbour porpoises were victims of grey seal attacks and that predation by this species is one of the main causes of death in harbour porpoises in The Netherlands. We provide a decision tree that will help in the identification of future cases of grey seal predation on porpoises. PMID:25429021

  11. Exposing the grey seal as a major predator of harbour porpoises.

    PubMed

    Leopold, Mardik F; Begeman, Lineke; van Bleijswijk, Judith D L; IJsseldijk, Lonneke L; Witte, Harry J; Gröne, Andrea

    2015-01-07

    Harbour porpoises (Phocoena phocoena) stranding in large numbers around the southern North Sea with fatal, sharp-edged mutilations have spurred controversy among scientists, the fishing industry and conservationists, whose views about the likely cause differ. The recent detection of grey seal (Halichoerus grypus) DNA in bite marks on three mutilated harbour porpoises, as well as direct observations of grey seal attacks on porpoises, have identified this seal species as a probable cause. Bite mark characteristics were assessed in a retrospective analysis of photographs of dead harbour porpoises that stranded between 2003 and 2013 (n = 1081) on the Dutch coastline. There were 271 animals that were sufficiently fresh to allow macroscopic assessment of grey seal-associated wounds with certainty. In 25% of these, bite and claw marks were identified that were consistent with the marks found on animals that had tested positive for grey seal DNA. Affected animals were mostly healthy juveniles that had a thick blubber layer and had recently fed. We conclude that the majority of the mutilated harbour porpoises were victims of grey seal attacks and that predation by this species is one of the main causes of death in harbour porpoises in The Netherlands. We provide a decision tree that will help in the identification of future cases of grey seal predation on porpoises.

  12. Grey leaves in an alpine plant: a cryptic colouration to avoid attack?

    PubMed

    Niu, Yang; Chen, Gao; Peng, De-Li; Song, Bo; Yang, Yang; Li, Zhi-Min; Sun, Hang

    2014-08-01

    Cryptic colouration is a common predation-avoidance strategy in animals that is postulated to occur in plants, but few experimental studies have rigorously tested this hypothesis. We investigated the colouration of Corydalis benecincta, an alpine plant with remarkably dimorphic leaf colours (grey and green), based on a cost-benefit analysis. First we tested the premise that herbivores (Parnassius butterflies) cannot distinguish grey leaves from a scree background by spectrographic measurements and by estimating discriminability between leaves and scree using a butterfly colour vision model. Then we estimated the potential costs of inconspicuousness by comparing the photosynthetic performance and visual attractiveness to flower visitors of the two colour morphs. Finally, we examined the potential benefits of inconspicuousness by comparing damage, survivorship and female reproductive success. It is difficult for herbivores to distinguish grey-coloured morphs against the background. This grey colour originates in a combination of anthocyanins and chlorophylls. The two colour morphs had similar photosynthetic performance, visual attractiveness and female reproductive success. However, grey morphs had significantly lower herbivore damage and higher survivorship. Grey leaves benefit C. benecincta by reducing herbivory with low investment in anthocyanin synthesis, and little cost on photosynthesis and mating opportunity. This cryptic colouration may have evolved through selection pressure imposed by visually foraging herbivores.

  13. Linkage of the grey coat colour locus to microsatellites on horse chromosome 25.

    PubMed

    Locke, M M; Penedo, M C T; Bricker, S J; Millon, L V; Murray, J D

    2002-10-01

    The progressive loss of colour in the hair of grey horses is controlled by a dominantly inherited allele at the Grey locus (GG). In this study, two paternal Quarter Horse (QH) families segregating for the GG allele were genotyped with a set of 101 microsatellite markers spanning the 31 autosomes and the X chromosome. This genome scan demonstrated linkage of Grey to COR018 (RF=0.02, LOD=12.04) on horse chromosome 25 (ECA25). Further chromosome-specific analysis of seven total QH families confirmed the linkage of Grey to a group of ECA25 markers and the map order of NVHEQ43-(0.24)-UCDEQ405-(0.09)-COR080-(0.05)-GREY-(0.14)-UCDEQ464 was produced. Although G was found to be linked to TXN and COR018 in the chromosome-specific analysis, the data were not sufficiently informative to place either marker on our ECA25 map with significant LODs. Our results excluded the equine tyrosinase related protein 1 (TYRP1) and melanocyte protein 17 (Pmel17) genes as possible candidates for the grey phenotype in horses.

  14. Whole genome grey and white matter DNA methylation profiles in dorsolateral prefrontal cortex.

    PubMed

    Sanchez-Mut, Jose Vicente; Heyn, Holger; Vidal, Enrique; Delgado-Morales, Raúl; Moran, Sebastian; Sayols, Sergi; Sandoval, Juan; Ferrer, Isidre; Esteller, Manel; Gräff, Johannes

    2017-01-20

    The brain's neocortex is anatomically organized into grey and white matter, which are mainly composed by neuronal and glial cells, respectively. The neocortex can be further divided in different Brodmann areas according to their cytoarchitectural organization, which are associated with distinct cortical functions. There is increasing evidence that brain development and function are governed by epigenetic processes, yet their contribution to the functional organization of the neocortex remains incompletely understood. Herein, we determined the DNA methylation patterns of grey and white matter of dorsolateral prefrontal cortex (Brodmann area 9), an important region for higher cognitive skills that is particularly affected in various neurological diseases. For avoiding interindividual differences, we analyzed white and grey matter from the same donor using whole genome bisulfite sequencing, and for validating their biological significance, we used Infinium HumanMethylation450 BeadChip and pyrosequencing in ten and twenty independent samples, respectively. The combination of these analysis indicated robust grey-white matter differences in DNA methylation. What is more, cell type-specific markers were enriched among the most differentially methylated genes. Interestingly, we also found an outstanding number of grey-white matter differentially methylated genes that have previously been associated with Alzheimer's, Parkinson's, and Huntington's disease, as well as Multiple and Amyotrophic lateral sclerosis. The data presented here thus constitute an important resource for future studies not only to gain insight into brain regional as well as grey and white matter differences, but also to unmask epigenetic alterations that might underlie neurological and neurodegenerative diseases.

  15. Socioeconomic status and the cerebellar grey matter volume. Data from a well-characterised population sample.

    PubMed

    Cavanagh, Jonathan; Krishnadas, Rajeev; Batty, G David; Burns, Harry; Deans, Kevin A; Ford, Ian; McConnachie, Alex; McGinty, Agnes; McLean, Jennifer S; Millar, Keith; Sattar, Naveed; Shiels, Paul G; Tannahill, Carol; Velupillai, Yoga N; Packard, Chris J; McLean, John

    2013-12-01

    The cerebellum is highly sensitive to adverse environmental factors throughout the life span. Socioeconomic deprivation has been associated with greater inflammatory and cardiometabolic risk, and poor neurocognitive function. Given the increasing awareness of the association between early-life adversities on cerebellar structure, we aimed to explore the relationship between early life (ESES) and current socioeconomic status (CSES) and cerebellar volume. T1-weighted MRI was used to create models of cerebellar grey matter volumes in 42 adult neurologically healthy males selected from the Psychological, Social and Biological Determinants of Ill Health study. The relationship between potential risk factors, including ESES, CSES and cerebellar grey matter volumes were examined using multiple regression techniques. We also examined if greater multisystem physiological risk index-derived from inflammatory and cardiometabolic risk markers-mediated the relationship between socioeconomic status (SES) and cerebellar grey matter volume. Both ESES and CSES explained the greatest variance in cerebellar grey matter volume, with age and alcohol use as a covariate in the model. Low CSES explained additional significant variance to low ESES on grey matter decrease. The multisystem physiological risk index mediated the relationship between both early life and current SES and grey matter volume in cerebellum. In a randomly selected sample of neurologically healthy males, poorer socioeconomic status was associated with a smaller cerebellar volume. Early and current socioeconomic status and the multisystem physiological risk index also apparently influence cerebellar volume. These findings provide data on the relationship between socioeconomic deprivation and a brain region highly sensitive to environmental factors.

  16. Mapping joint grey and white matter reductions in Alzheimer's disease using joint independent component analysis.

    PubMed

    Guo, Xiaojuan; Han, Yuan; Chen, Kewei; Wang, Yan; Yao, Li

    2012-12-07

    Alzheimer's disease (AD) is a neurodegenerative disease concomitant with grey and white matter damages. However, the interrelationship of volumetric changes between grey and white matter remains poorly understood in AD. Using joint independent component analysis, this study identified joint grey and white matter volume reductions based on structural magnetic resonance imaging data to construct the covariant networks in twelve AD patients and fourteen normal controls (NC). We found that three networks showed significant volume reductions in joint grey-white matter sources in AD patients, including (1) frontal/parietal/temporal-superior longitudinal fasciculus/corpus callosum, (2) temporal/parietal/occipital-frontal/occipital, and (3) temporal-precentral/postcentral. The corresponding expression scores distinguished AD patients from NC with 85.7%, 100% and 85.7% sensitivity for joint sources 1, 2 and 3, respectively; 75.0%, 66.7% and 75.0% specificity for joint sources 1, 2 and 3, respectively. Furthermore, the combined source of three significant joint sources best predicted the AD/NC group membership with 92.9% sensitivity and 83.3% specificity. Our findings revealed joint grey and white matter loss in AD patients, and these results can help elucidate the mechanism of grey and white matter reductions in the development of AD.

  17. Towards a Holistic Cortical Thickness Descriptor: Heat Kernel-Based Grey Matter Morphology Signatures.

    PubMed

    Wang, Gang; Wang, Yalin

    2017-02-15

    In this paper, we propose a heat kernel based regional shape descriptor that may be capable of better exploiting volumetric morphological information than other available methods, thereby improving statistical power on brain magnetic resonance imaging (MRI) analysis. The mechanism of our analysis is driven by the graph spectrum and the heat kernel theory, to capture the volumetric geometry information in the constructed tetrahedral meshes. In order to capture profound brain grey matter shape changes, we first use the volumetric Laplace-Beltrami operator to determine the point pair correspondence between white-grey matter and CSF-grey matter boundary surfaces by computing the streamlines in a tetrahedral mesh. Secondly, we propose multi-scale grey matter morphology signatures to describe the transition probability by random walk between the point pairs, which reflects the inherent geometric characteristics. Thirdly, a point distribution model is applied to reduce the dimensionality of the grey matter morphology signatures and generate the internal structure features. With the sparse linear discriminant analysis, we select a concise morphology feature set with improved classification accuracies. In our experiments, the proposed work outperformed the cortical thickness features computed by FreeSurfer software in the classification of Alzheimer's disease and its prodromal stage, i.e., mild cognitive impairment, on publicly available data from the Alzheimer's Disease Neuroimaging Initiative. The multi-scale and physics based volumetric structure feature may bring stronger statistical power than some traditional methods for MRI-based grey matter morphology analysis.

  18. The grey relational approach for evaluating measurement uncertainty with poor information

    NASA Astrophysics Data System (ADS)

    Luo, Zai; Wang, Yanqing; Zhou, Weihu; Wang, Zhongyu

    2015-12-01

    The Guide to the Expression of Uncertainty in Measurement (GUM) is the master document for measurement uncertainty evaluation. However, the GUM may encounter problems and does not work well when the measurement data have poor information. In most cases, poor information means a small data sample and an unknown probability distribution. In these cases, the evaluation of measurement uncertainty has become a bottleneck in practical measurement. To solve this problem, a novel method called the grey relational approach (GRA), different from the statistical theory, is proposed in this paper. The GRA does not require a large sample size or probability distribution information of the measurement data. Mathematically, the GRA can be divided into three parts. Firstly, according to grey relational analysis, the grey relational coefficients between the ideal and the practical measurement output series are obtained. Secondly, the weighted coefficients and the measurement expectation function will be acquired based on the grey relational coefficients. Finally, the measurement uncertainty is evaluated based on grey modeling. In order to validate the performance of this method, simulation experiments were performed and the evaluation results show that the GRA can keep the average error around 5%. Besides, the GRA was also compared with the grey method, the Bessel method, and the Monte Carlo method by a real stress measurement. Both the simulation experiments and real measurement show that the GRA is appropriate and effective to evaluate the measurement uncertainty with poor information.

  19. 2015 Space Radiation Standing Review Panel

    NASA Technical Reports Server (NTRS)

    Steinberg, Susan

    2015-01-01

    The 2015 Space Radiation Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on December 8 - 9, 2015. The SRP met with representatives from the Space Radiation Element and members of the Human Research Program (HRP) to review the updated research plan for the Risk of Radiation Carcinogenesis Cancer Risk. The SRP also reviewed the newly revised Evidence Reports for the Risk of Acute Radiation Syndromes Due to Solar Particle Events (SPEs) (Acute Risk), the Risk of Acute (In-flight) and Late Central Nervous System Effects from Radiation Exposure (CNS Risk), and the Risk of Cardiovascular Disease and Other Degenerative Tissue Effects from Radiation (Degen Risk), as well as a status update on these Risks. The SRP would like to commend Dr. Simonsen, Dr. Huff, Dr. Nelson, and Dr. Patel for their detailed presentations. The Space Radiation Element did a great job presenting a very large volume of material. The SRP considers it to be a strong program that is well-organized, well-coordinated and generates valuable data. The SRP commended the tissue sharing protocols, working groups, systems biology analysis, and standardization of models. In several of the discussed areas the SRP suggested improvements of the research plans in the future. These include the following: It is important that the team has expanded efforts examining immunology and inflammation as important components of the space radiation biological response. This is an overarching and important focus that is likely to apply to all aspects of the program including acute, CVD, CNS, cancer and others. Given that the area of immunology/inflammation is highly complex (and especially so as it relates to radiation), it warrants the expansion of investigators expertise in immunology and inflammation to work with the individual research projects and also the NASA Specialized Center of Research (NSCORs). Historical data on radiation injury to be entered into the Watson

  20. Trauma-specific Grey Matter Alterations in PTSD

    PubMed Central

    Meng, Linghui; Jiang, Jing; Jin, Changfeng; Liu, Jia; Zhao, Youjin; Wang, Weina; Li, Kaiming; Gong, Qiyong

    2016-01-01

    Previous studies have demonstrated that patients with posttraumatic stress disorder (PTSD) caused by different types of trauma may show divergence in epidemiology, clinical manifestation and treatment outcome. However, it is still unclear whether this divergence has neuroanatomic correlates in PTSD brains. To elucidate the general and trauma-specific cortical morphometric alterations, we performed a meta-analysis of grey matter (GM) changes in PTSD (N = 246) with different traumas and trauma-exposed controls (TECs, N = 347) using anisotropic effect-size signed differential mapping and its subgroup analysis. Our results revealed general GM reduction (GMR) foci in the prefrontal-limbic-striatal system of PTSD brains when compared with those of TECs. Notably, the GMR patterns were trauma-specific. For PTSD by single-incident traumas, GMR foci were found in bilateral medial prefrontal cortex (mPFC), anterior cingulate cortex (ACC), insula, striatum, left hippocampus and amygdala; and for PTSD by prolonged traumas in the left insula, striatum, amygdala and middle temporal gyrus. Moreover, Clinician-Administered PTSD Scale scores were found to be negatively associated with the GM changes in bilateral ACC and mPFC. Our study indicates that the GMR patterns of PTSD are associated with specific traumas, suggesting a stratified diagnosis and treatment for PTSD patients. PMID:27651030

  1. Dysbiotic drift: mental health, environmental grey space, and microbiota.

    PubMed

    Logan, Alan C

    2015-05-07

    Advances in research concerning the mental health implications of dietary patterns and select nutrients have been remarkable. At the same time, there have been rapid increases in the understanding of the ways in which non-pathogenic microbes can potentially influence many aspects of human health, including those in the mental realm. Discussions of nutrition and microbiota are often overlapping. A separate, yet equally connected, avenue of research is that related to natural (for example, green space) and built environments, and in particular, how they are connected to human cognition and behaviors. It is argued here that in Western industrial nations a 'disparity of microbiota' might be expected among the socioeconomically disadvantaged, those whom face more profound environmental forces. Many of the environmental forces pushing against the vulnerable are at the neighborhood level. Matching the developing microbiome research with existing environmental justice research suggests that grey space may promote dysbiosis by default. In addition, the influence of Westernized lifestyle patterns, and the marketing forces that drive unhealthy behaviors in deprived communities, might allow dysbiosis to be the norm rather than the exception in those already at high risk of depression, subthreshold (subsyndromal) conditions, and subpar mental health. If microbiota are indeed at the intersection of nutrition, environmental health, and lifestyle medicine (as these avenues pertain to mental health), then perhaps the rapidly evolving gut-brain-microbiota conversation needs to operate through a wider lens. In contrast to the more narrowly defined psychobiotic, the term eco-psychotropic is introduced.

  2. Architectonic subdivisions of neocortex in the grey squirrel (Sciurus carolinensis)

    PubMed Central

    Wong, Peiyan; Kaas, Jon H.

    2010-01-01

    Squirrels are highly visual mammals with an expanded cortical visual system and a number of well-differentiated architectonic fields. In order to describe and delimit cortical fields, subdivisions of cortex were reconstructed from serial brain sections cut in the coronal, sagittal, or horizontal planes. Architectonic characteristics of cortical areas were visualized after brain sections were processed with immunohistochemical and histochemical procedures for revealing parvalbumin, calbindin, neurofilament protein, vesicle glutamate transporter 2, limbic-associated membrane protein, synaptic zinc, cytochrome oxidase, myelin or Nissl substance. In general, these different procedures revealed similar boundaries between areas, suggesting that functionally relevant borders were being detected. The results allowed a more precise demarcation of previously identified areas as well as the identification of areas that had not been previously described. Primary sensory cortical areas characterized by sparse zinc staining of layer 4, as thalamocortical terminations lack zinc, as well as by layer 4 terminations rich in parvalbumin and vesicle glutamate transporter 2. Primary areas also expressed higher levels of cytochrome oxidase and myelin. Primary motor cortex was associated with large SMI-32 labeled pyramidal cells in layers 3 and 5. Our proposed organization of cortex in grey squirrels includes both similarities and differences to the proposed of cortex in other rodents such as mice and rats. The presence of a number of well-differentiated cortical areas in squirrels may serve as a guide to the identification of homologous fields in other rodents, as well as a useful guide in further studies of cortical organization and function. PMID:18780299

  3. First isolation of Mycoplasma iowae in grey partridge flocks.

    PubMed

    Catania, S; Gobbo, F; Rodio, S; Qualtieri, K; Santone, C; Nicholas, R A J

    2014-06-01

    Mycoplasma iowae, an occasional pathogen of turkeys, was isolated for the first time from captive grey partridges (Perdix perdix). Clinical signs including respiratory and intestinal disorder were seen in birds of all ages but mainly in those kept housed during rearing. Mortality rates averaged over 20% during the year. Treatment with antibiotics and antiparasitic drugs produced only a transient improvement in condition. The gross pathology findings included poor body growth, lack of development of the breast muscles, abnormalities in the keel development, and bone fragility. Some birds showed infraorbital sinusitis with serous or fibrinous exudates and catarrhal tracheitis, while others presented serofibrinous airsacculitis and splenomegaly. Laboratory investigations revealed pure cultures of M. iowae in the gut as well as sinus and air sacs. While other organisms such as coccidia, Trichomonas, Escherichia coli, Clostridium perfringens, and Aspergillus spp. were detected, the similarity of the disease with that seen in turkeys infected with M. iowae strongly suggests that this mycoplasma may be the primary pathogen here. The presence of M. iowae in game birds commonly released into the wild could have serious implications particularly in areas where industrial poultry farms are concentrated.

  4. Comparative Cytogenetics of the Congo African Grey Parrot (Psittacus erithacus).

    PubMed

    Seibold-Torres, Cassandra; Owens, Elaine; Chowdhary, Renuka; Ferguson-Smith, Malcolm A; Tizard, Ian; Raudsepp, Terje

    2015-01-01

    The Congo African grey parrot (Psittacus erithacus, PER) is an endemic species of Central Africa, valued for its intelligence and listed as vulnerable due to poaching and habitat destruction. Improved knowledge about the P. erithacus genome is needed to address key biological questions and conservation of this species. The P. erithacus genome was studied using conventional and molecular cytogenetic approaches including Zoo-FISH. P. erithacus has a 'typical' parrot karyotype with 2n = 62-64 and 8 pairs of macrochromosomes. A distinct feature was a sharp macro-microchromosome boundary. Telomeric sequences were present at all chromosome ends and interstitially in PER2q, the latter coinciding with a C-band. NORs mapped to 4 pairs of microchromosomes which is in contrast to a single NOR in ancestral type avian karyotypes. Zoo-FISH with chicken macrochromosomes GGA1-9 and Z revealed patterns of conserved synteny similar to many other avian groups, though neighboring synteny combinations of GGA6/7, 8/9, and 1/4 were distinctive only to parrots. Overall, P. erithacus shared more Zoo-FISH patterns with neotropical macaws than Australian species such as cockatiel and budgerigar. The observations suggest that Psittaciformes karyotypes have undergone more extensive evolutionary rearrangements compared to the majority of other avian genomes.

  5. Pathological differences between white and grey matter multiple sclerosis lesions.

    PubMed

    Prins, Marloes; Schul, Emma; Geurts, Jeroen; van der Valk, Paul; Drukarch, Benjamin; van Dam, Anne-Marie

    2015-09-01

    Multiple sclerosis (MS) is a debilitating disease characterized by demyelination of the central nervous system (CNS), resulting in widespread formation of white matter lesions (WMLs) and grey matter lesions (GMLs). WMLs are pathologically characterized by the presence of immune cells that infiltrate the CNS, whereas these immune cells are barely present in GMLs. This striking pathological difference between WMLs and GMLs raises questions about the underlying mechanism. It is known that infiltrating leukocytes contribute to the generation of WMLs; however, since GMLs show a paucity of infiltrating immune cells, their importance in GML formation remains to be determined. Here, we review pathological characteristics of WMLs and GMLs, and suggest some possible explanations for the observed pathological differences. In our view, cellular and molecular characteristics of WM and GM, and local differences within WMLs and GMLs (in particular, in glial cell populations and the molecules they express), determine the pathway to demyelination. Further understanding of GML pathogenesis, considered to contribute to chronic MS, may have a direct impact on the development of novel therapeutic targets to counteract this progressive neurological disorder.

  6. Ecological factors influence population genetic structure of European grey wolves.

    PubMed

    Pilot, Malgorzata; Jedrzejewski, Wlodzimierz; Branicki, Wojciech; Sidorovich, Vadim E; Jedrzejewska, Bogumila; Stachura, Krystyna; Funk, Stephan M

    2006-12-01

    Although the mechanisms controlling gene flow among populations are particularly important for evolutionary processes, they are still poorly understood, especially in the case of large carnivoran mammals with extensive continuous distributions. We studied the question of factors affecting population genetic structure in the grey wolf, Canis lupus, one of the most mobile terrestrial carnivores. We analysed variability in mitochondrial DNA and 14 microsatellite loci for a sample of 643 individuals from 59 localities representing most of the continuous wolf range in Eastern Europe. We tested an array of geographical, historical and ecological factors to check whether they may explain genetic differentiation among local wolf populations. We showed that wolf populations in Eastern Europe displayed nonrandom spatial genetic structure in the absence of obvious physical barriers to movement. Neither topographic barriers nor past fragmentation could explain spatial genetic structure. However, we found that the genetic differentiation among local populations was correlated with climate, habitat types, and wolf diet composition. This result shows that ecological processes may strongly influence the amount of gene flow among populations. We suggest natal-habitat-biased dispersal as an underlying mechanism linking population ecology with population genetic structure.

  7. Circadian Rhythms of Isoprene Biosynthesis in Grey Poplar Leaves1

    PubMed Central

    Loivamäki, Maaria; Louis, Sandrine; Cinege, Gyöngyi; Zimmer, Ina; Fischbach, Robert J.; Schnitzler, Jörg-Peter

    2007-01-01

    Isoprene (2-methyl-1,3-butadiene) emission varies diurnally in different species. In poplar (Populus spp.), it has recently been shown that the gene encoding the synthesizing enzyme for isoprene, isoprene synthase (ISPS), displays diurnal variation in expression. Working on shoot cultures of Grey poplar (Populus × canescens) placed under a different light regime in phytochambers, we showed that these variations in PcISPS gene expression, measured by quantitative real-time polymerase chain reaction, are not only due to day-night changes, but also are linked to an internal circadian clock. Measurement of additional selected isoprenoid genes revealed that phytoene synthase (carotenoid pathway) displays similar fluctuations, whereas 1-deoxy-d-xylulose 5-phosphate reductoisomerase, possibly the first committed enzyme of the 1-deoxy-d-xylulose 5-phosphate pathway, only shows light regulation. On the protein level, it appeared that PcISPS activity and protein content became reduced under constant darkness, whereas under constant light, activity and protein content of this enzyme were kept high. In contrast, isoprene emission rates under continuous irradiation displayed circadian changes as is the case for gene expression of PcISPS. Furthermore, binding assays with Arabidopsis (Arabidopsis thaliana) late elongated hypocotyl, a transcription factor of Arabidopsis involved in circadian regulation, clearly revealed the presence of circadian-determining regulatory elements in the promoter region of PcISPS. PMID:17122071

  8. Juvenile offenders: competence to stand trial.

    PubMed

    Soulier, Matthew

    2012-12-01

    This article details the legal background and assists the reader in the preparation and practical conduct of evaluations regarding juvenile adjudicative competency. The material is presented to be useful as a guide to direct questions of competency and covers aspects of evaluation that include: legal standard for competency to stand trial, developmental immaturity, current practice in juvenile competency to stand trial, forensic evaluation of juvenile competency to stand trial, organizing the evaluation, collateral sources of information, psychiatric evaluation of juvenile adjudicative competency, assessment of mental disorder and intellectual disability, assessment of developmental status, assessment of functional abilities for adjudicative competence, and reaching the forensic opinion.

  9. A drive system to add standing mobility to a manual standing wheelchair.

    PubMed

    Nickel, Eric; Hansen, Andrew; Pearlman, Jonathan; Goldish, Gary

    2016-05-16

    Current manual standing wheelchairs are not mobile in the standing position. The addition of standing mobility may lead to improved health and function for the user and may increase utilization of standing wheelchairs. In this project, a chain drive system was fitted to a manual standing wheelchair, adding mobility in the standing position. The hand rims are accessible from both seated and standing positions. The prototype uses 16-inch drive wheels in front with casters in the rear. Additional anterior casters are elevated when seated for navigating obstacles and then descend when standing to create a six-wheeled base with extended anterior support. Stability testing shows the center of pressure remains within the base of support when leaning to the sides or front in both seated and standing positions. Four veterans with spinal cord injury provided feedback on the design and reported that mobility during standing was very important or extremely important to them. The veterans liked the perceived stability and mobility of the prototype and provided feedback for future refinements. For example, reducing the overall width (width from hand rim to hand rim) and weight could make this system more functional for users.

  10. Bite Injuries of Grey Seals (Halichoerus grypus) on Harbour Porpoises (Phocoena phocoena)

    PubMed Central

    Loos, Pauline; Bourgain, Jean-Luc; Bouveroux, Thibaut; Coignoul, Freddy; Haelters, Jan; Karpouzopoulos, Jacky; Pezeril, Sylvain; Desmecht, Daniel

    2014-01-01

    Bite-like skin lesions on harbour porpoises (Phocoena phocoena) have been suspected to be caused by grey seals (Halichoerus grypus), and a few field observations have been reported. Bite-like skin lesions observed on stranded animals were characterized by two main components: large flaps of loose or missing skin and blubber with frayed edges and puncture lesions. Definitive demonstration of predation by a grey seal was not reported so far in those stranded animals. In this study, five stranded porpoises with bite-like skin lesions were swabbed for genetic investigations. In addition, the head of a recently dead grey seal was used to mimic bite-like skin injuries on a porpoise carcass. Subsequently, the artificial skin injuries were swabbed, along with the gum of the seal used for inflicting them (positive controls). Total DNA was extracted from the swabs and was used to retrieve a fragment of mitochondrial DNA by PCR. Primers were designed to amplify a specific stretch of mitochondrial DNA known to differ between grey seals and porpoises. The amplicon targeted was successfully amplified from the positive control and from two of the stranded porpoises, and grey seal-specific mitochondrial DNA was retrieved from all those samples. We conclude that (1) it is possible to detect grey seal DNA from dead porpoises even after several days in seawater and (2) bite-like skin lesions found on dead porpoises definitively result from grey seals attacks. The attacks are most likely linked with predation although, in a number of cases, scavenging and aggressive behaviour cannot be excluded. PMID:25461599

  11. Bite injuries of grey seals (Halichoerus grypus) on harbour porpoises (Phocoena phocoena).

    PubMed

    Jauniaux, Thierry; Garigliany, Mutien-Marie; Loos, Pauline; Bourgain, Jean-Luc; Bouveroux, Thibaut; Coignoul, Freddy; Haelters, Jan; Karpouzopoulos, Jacky; Pezeril, Sylvain; Desmecht, Daniel

    2014-01-01

    Bite-like skin lesions on harbour porpoises (Phocoena phocoena) have been suspected to be caused by grey seals (Halichoerus grypus), and a few field observations have been reported. Bite-like skin lesions observed on stranded animals were characterized by two main components: large flaps of loose or missing skin and blubber with frayed edges and puncture lesions. Definitive demonstration of predation by a grey seal was not reported so far in those stranded animals. In this study, five stranded porpoises with bite-like skin lesions were swabbed for genetic investigations. In addition, the head of a recently dead grey seal was used to mimic bite-like skin injuries on a porpoise carcass. Subsequently, the artificial skin injuries were swabbed, along with the gum of the seal used for inflicting them (positive controls). Total DNA was extracted from the swabs and was used to retrieve a fragment of mitochondrial DNA by PCR. Primers were designed to amplify a specific stretch of mitochondrial DNA known to differ between grey seals and porpoises. The amplicon targeted was successfully amplified from the positive control and from two of the stranded porpoises, and grey seal-specific mitochondrial DNA was retrieved from all those samples. We conclude that (1) it is possible to detect grey seal DNA from dead porpoises even after several days in seawater and (2) bite-like skin lesions found on dead porpoises definitively result from grey seals attacks. The attacks are most likely linked with predation although, in a number of cases, scavenging and aggressive behaviour cannot be excluded.

  12. Copy number expansion of the STX17 duplication in melanoma tissue from Grey horses

    PubMed Central

    2012-01-01

    Background Greying with age in horses is an autosomal dominant trait, associated with loss of hair pigmentation, melanoma and vitiligo-like depigmentation. We recently identified a 4.6 kb duplication in STX17 to be associated with the phenotype. The aims of this study were to investigate if the duplication in Grey horses shows copy number variation and to exclude that any other polymorphism is uniquely associated with the Grey mutation. Results We found little evidence for copy number expansion of the duplicated sequence in blood DNA from Grey horses. In contrast, clear evidence for copy number expansions was indicated in five out of eight tested melanoma tissues or melanoma cell lines. A tendency of a higher copy number in aggressive tumours was also found. Massively parallel resequencing of the ~350 kb Grey haplotype did not reveal any additional mutations perfectly associated with the phenotype, confirming the duplication as the true causative mutation. We identified three SNP alleles that were present in a subset of Grey haplotypes within the 350 kb region that shows complete linkage disequilibrium with the causative mutation. Thus, these three nucleotide substitutions must have occurred subsequent to the duplication, consistent with our interpretation that the Grey mutation arose more than 2,000 years before present. Conclusions These results suggest that the mutation acts as a melanoma-driving regulatory element. The elucidation of the mechanistic features of the duplication will be of considerable interest for the characterization of these horse melanomas as well as for the field of human melanoma research. PMID:22857264

  13. Crutches and children - standing and walking

    MedlinePlus

    ... patientinstructions/000641.htm Crutches and children - standing and walking To use the sharing features on this page, ... leg. Keep the crutches slightly forward and apart. Walking with Crutches (No Weight Bearing on Hurt Foot ...

  14. Timelapse: Webb's Ambient Optical Assembly Stand

    NASA Video Gallery

    The clean room at NASA's Goddard Space Flight Center in Greenbelt, Md., has received a giant structural steel frame called "AOAS," the Ambient Optical Assembly Stand that will be used to assemble t...

  15. 15 CFR 10.8 - Standing Committee.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... general interest groups such as municipal, State, and Federal agencies. When requested by the Standing... technology that might affect the standard; (2) Provide the Department with interpretations of provisions...

  16. A Mathematical Prediction of Standing Waves

    ERIC Educational Resources Information Center

    Higgins, Jon

    1970-01-01

    Presents a problem in standing waves that provides an example of the mathematics used by theoretical physicists to generate predictions of new phenomena from fundamental background knowledge. Mathematical analysis required to solve problem is accomplished by simple graphical processes. (BR)

  17. Steel erected at A-3 Test Stand

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Workers erect the first fabricated steel girders to arrive at the A-3 Test Stand at Stennis Space Center. Steel work began at the construction site Oct. 29 and is scheduled to continue into next spring.

  18. Stress analysis of down force calibration stand

    SciTech Connect

    COVERDELL, B.L.

    1998-10-01

    This document presents the stress analysis of the Down Force Calibration Stand. All structural components were evaluated and found to be adequate to withstand the applicable design loads meeting all codes and standards requirements.

  19. Lisa's Lemonade Stand: Exploring Algebraic Ideas.

    ERIC Educational Resources Information Center

    Billings, Esther M. H.; Lakatos, Tracy

    2003-01-01

    Presents an activity, "Lisa's Lemonade Stand," that actively engages students in algebraic thinking as they analyze change by investigating relationships between variables and gain experience describing and representing these relationships graphically. (YDS)

  20. Saturn IB in MSFC Dynamic Test Stand

    NASA Technical Reports Server (NTRS)

    1965-01-01

    A completely assembled Saturn IB launch vehicle stands in the Marshall Space Flight Center (MSFC) Dynamic Test Stand, April 14, 1965, for testing on the structural integrity of the vehicle. Developed by the MSFC as an interim vehicle in MSFC's 'building block' approach to Saturn rocket development, the Saturn IB utilized Saturn I technology to further develop and refine large boosters and the Apollo spacecraft capabilities required for the marned lunar missions.

  1. Inexpensive Guitar Stand Project Really Rocks!

    ERIC Educational Resources Information Center

    Horath, Larry; Horath, Elyse

    2010-01-01

    Anyone who plays a guitar needs a stand to hold the guitar when he or she is not playing it. A guitar is not an instrument that one can lay down or prop against the wall without risking potentially catastrophic and long-term damage. There are several options in pre-made guitar stands made for single or multiple guitars, but as an alternative that…

  2. Grey zone simulations of the morning convective boundary layer development

    NASA Astrophysics Data System (ADS)

    Efstathiou, G. A.; Beare, R. J.; Osborne, S.; Lock, A. P.

    2016-05-01

    Numerical simulations of two cases of morning boundary layer development are conducted to investigate the impact of grid resolution on mean profiles and turbulent kinetic energy (TKE) partitioning from the large eddy simulation (LES) to the mesoscale limit. Idealized LES, using the 3-D Smagorinsky scheme, is shown to be capable of reproducing the boundary layer evolution when compared against measurements. However, increasing grid spacing results in the damping of resolved TKE and the production of superadiabatic temperature profiles in the boundary layer. Turbulence initiation is significantly delayed, exhibiting an abrupt onset at intermediate resolutions. Two approaches, the bounding of vertical diffusion coefficient and the blending of the 3-D Smagorinsky with a nonlocal 1D scheme, are used to model subgrid diffusion at grey zone resolutions. Simulations are compared against the coarse-grained fields from the validated LES results for each case. Both methods exhibit particular strengths and weaknesses, indicating the compromise that needs to be made currently in high-resolution numerical weather prediction. The blending scheme is able to reproduce the adiabatic profiles although turbulence is underestimated in favor of the parametrized heat flux, and the spin-up of TKE remains delayed. In contrast, the bounding approach gives an evolution of TKE that follows the coarse-grained LES very well, relying on the resolved motions for the nonlocal heat flux. However, bounding gives unrealistic static instability in the early morning temperature profiles (similar to the 3-D Smagorinsky scheme) because model dynamics are unable to resolve TKE when the boundary layer is too shallow compared to the grid spacing.

  3. 2. EAST ELEVATION OF POWER PLANT TEST STAND (HORIZONTAL TEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. EAST ELEVATION OF POWER PLANT TEST STAND (HORIZONTAL TEST STAND REMNANTS OF BUILDING-BLANK WHITE WALL ONLY ORIGINAL REMAINS. - Marshall Space Flight Center, East Test Area, Power Plant Test Stand, Huntsville, Madison County, AL

  4. 31. HISTORIC VIEW OF TEST STAND NO. 1 AT PEENEMUENDE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. HISTORIC VIEW OF TEST STAND NO. 1 AT PEENEMUENDE A-4 ENGINE AND ROCKET PROPULSION TEST STAND. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

  5. Birch Stands Growth Increase in Western Siberia

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Kuzmichev, Valeriy V.; Im, Sergey T.; Ranson, Kenneth J.

    2014-01-01

    Birch (Betula pendula Roth) growth within the Western Siberia forest-steppe was analyzed based on long-term (1897-2006) inventory data (height, diameter at breast height [dbh], and stand volume). Analysis of biometry parameters showed increased growth at the beginning of twenty-first century compared to similar stands (stands age = 40-60 years) at the end of nineteenth century. Mean height, dbh, and stem volume increased from 14 to 20 m, from 16 to 22 cm, and from approx. 63 to approx. 220 cu m/ha, respectively. Significant correlations were found between the stands mean height, dbh, and volume on the one hand, and vegetation period length (r(sub s) = 0.71 to 0.74), atmospheric CO2 concentration (r(sub s) = 0.71 to 0.76), and drought index (Standardized Precipitation-Evapotranspiration Index, r(sub s) = -0.33 to -0.51) on the other hand. The results obtained have revealed apparent climate-induced impacts (e.g. increase of vegetation period length and birch habitat drying due to drought increase) on the stands growth. Along with this, a high correlation of birch biometric parameters and [CO2] in ambient air indicated an effect of CO2 fertilization. Meanwhile, further drought increase may switch birch stand growth into decline and greater mortality as has already been observed within the Trans-Baikal forest-steppe ecotone.

  6. Guitar Strings as Standing Waves: A Demonstration

    NASA Astrophysics Data System (ADS)

    Davis, Michael

    2007-08-01

    An undergraduate student's first exposure to modern atomic theory tends to start with Bohr's model of the atom. This familiar introduction to atomic structure also marks a general chemistry student's first foray into waves. Many popular chemistry textbooks illustrate the concept of a standing wave in the development of the modern quantum model by using the phrase “as seen on a guitar string”. In these illustrations, the wave itself is often small and difficult to discern. The same phenomenon, however, can be easily and audibly observed. This demonstration uses an acoustic guitar to produce three unique harmonic vibrations, each of which is representative of a standing wave and illustrates the concept of quantization. Manipulation of the guitar string to produce a standing wave is pervasive in popular music and is audibly recognizable. Lightly placing a finger on the 12th, 7th, or 5th fret and strumming any one or all six strings can produce an audible example of a standing wave on a guitar. This corresponds to a standing wave with 1, 2, or 3 nodes, respectively. Attempting to induce a node at other points on a guitar string does not generate a standing wave, due to destructive interference, thus no audible tone is produced.

  7. A new insight on the gas phase retro-Diels-Alder reaction of bicyclic compounds: density functional theory calculations

    NASA Astrophysics Data System (ADS)

    Mora, Jose R.; Lezama, Jesús; Córdova-Sintjago, Tania C.; Chuchani, Gabriel

    2015-11-01

    The mechanisms of the gas-phase thermal decomposition of bicyclo[2.2.1]heptadiene and 3,7,7-trimethylbicyclo[2.2.1]hept-2-ene were examined by density functional theory calculations with the hybrid functionals: B3LYP, CAM-B3LYP, MPW1PW91, and PBEPBE. Reasonable agreements were found between theoretical and experimental values with the B3LYP hybrid functional. Three molecular concerted pathways for bicyclo[2.2.1]heptadiene decomposition are proposed. The retro-Diels-Alder (retro-DA) pathway yields cyclopentadiene and acetylene through a nearly synchronous transition state structure (Sy = 0.97). The other two reaction channels are stepwise with a common step with the formation of the intermediate bicyclo[4.1.0] heptadiene. This reaction is dominated by C-C bond breaking leading to the methylene migration by an early transition state in the reaction coordinate (Sy = 0.91). The rearrangements of the latter intermediate producing toluene were also studied. The retro-DA elimination of 3,7,7-trimethylbicyclo[2.2.1]hept-2-ene gives 1,5,5-trimethyl-cyclopenta-1,3-diene in a less synchronous process (Sy = 0.77). This fact may be due to the electronic effects of the methyl substituent. The latter product is unstable and undergoes methyl migrations to give a more stable isomer 1,2,3-trimethylcyclopenta-1,3-diene. The stepwise mechanism for the retro-DA reaction through a biradical intermediate appears to be unfavourable because the barrier is bigger than that for the concerted reaction.

  8. A new biopesticide from a local Bacillus thuringiensis var. tenebrionis (Xd3) against alder leaf beetle (Coleoptera: Chrysomelidae).

    PubMed

    Eski, Ardahan; Demir, İsmail; Sezen, Kazım; Demirbağ, Zihni

    2017-05-01

    Use of chemical pesticides in agriculture harms humans, non-target organisms and environments, and causes increase resistance against chemicals. In order to develop an effective bio-pesticide against coleopterans, particularly against Agelastica alni (Coleoptera: Chrysomelidae) which is one of the serious pests of alder leaf and hazelnut, we tested the insecticidal effect of 21 Bacillus isolates against the larvae and adults of the pest. Bacillus thuringiensis var. tenebrionis-Xd3 (Btt-Xd3) showed the highest insecticidal effect based on screening tests. For toxin protein production and high sporulation of Xd3, the most suitable medium, pH and temperature conditions were determined as nutrient broth medium enriched with salts, pH 7 and 30 °C, respectively. Sporulated Btt-Xd3 in nutrient broth medium enriched with salts transferred to fermentation medium containing soybean flour, glucose and salts. After fermentation, the mixture was dried in a spray dryer, and spore count of the powder product was determined as 1.6 × 10(10) c.f.u. g(-1). Moisture content, suspensibility and wettability of the formulation were determined as 8.3, 86% and 21 s, respectively. Lethal concentrations (LC50) of formulated Btt-Xd3 were determined as 0.15 × 10(5) c.f.u. ml(-1) for larvae at laboratory conditions. LC50 values were also determined as 0.45 × 10(6) c.f.u. ml(-1) at the field condition on larval stage. Our results showed that a new bio-pesticide developed from B. thuringiensis tenebrionis (Xd3) (Btt-Xd3) may be valuable as a biological control agent for coleopteran pests.

  9. Development of prolonged standing strain index to quantify risk levels of standing jobs.

    PubMed

    Halim, Isa; Omar, Abdul Rahman

    2012-01-01

    Many occupations in industry such as metal stamping workers, electronics parts assembly operators, automotive industry welders, and lathe operators require working in a standing posture for a long time. Prolonged standing can contribute to discomfort and muscle fatigue particularly in the back and legs. This study developed the prolonged standing strain index (PSSI) to quantify the risk levels caused by standing jobs, and proposed recommendations to minimize the risk levels. Risk factors associated with standing jobs, such as working posture, muscles activity, standing duration, holding time, whole-body vibration, and indoor air quality, were the basis for developing the PSSI. All risk factors were assigned multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness. multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness.

  10. Yellowing and bleaching of grey hair caused by photo and thermal degradation.

    PubMed

    Richena, M; Silveira, M; Rezende, C A; Joekes, I

    2014-09-05

    Yellowing is an undesirable phenomenon that is common in people with white and grey hair. Because white hair has no melanin, the pigment responsible for hair colour, the effects of photodegradation are more visible in this type of hair. The origin of yellowing and its relation to photodegradation processes are not properly established, and many questions remain open in this field. In this work, the photodegradation of grey hair was investigated as a function of the wavelength of incident radiation, and its ultrastructure was determined, always comparing the results obtained for the white and black fibres present in grey hair with the results of white wool. The results presented herein indicate that the photobehaviour of grey hair irradiated with a mercury lamp or with solar radiation is dependent on the wavelength range of the incident radiation and on the initial shade of yellow in the sample. Two types of grey hair were used: (1) blended grey hair (more yellow) and (2) grey hair from a single-donor (less yellow). After exposure to a full-spectrum mercury lamp for 200 h, the blended white hair turned less yellow (the yellow-blue difference, Db(*) becomes negative, Db(*)=-6), whereas the white hair from the single-donor turned slightly yellower (Db(*)=2). In contrast, VIS+IR irradiation resulted in bleaching in both types of hair, whereas a thermal treatment (at 81 °C) caused yellowing of both types of hair, resulting in a Db(*)=3 for blended white hair and Db(*)=9 for single-donor hair. The identity of the yellow chromophores was investigated by UV-Vis spectroscopy. The results obtained with this technique were contradictory, however, and it was not possible to obtain a simple correlation between the sample shade of yellow and the absorption spectra. In addition, the results are discussed in terms of the morphology differences between the pigmented and non-pigmented parts of grey hair, the yellowing and bleaching effects of grey hair, and the occurrence of dark

  11. Right hemisphere grey matter structure and language outcomes in chronic left hemisphere stroke.

    PubMed

    Xing, Shihui; Lacey, Elizabeth H; Skipper-Kallal, Laura M; Jiang, Xiong; Harris-Love, Michelle L; Zeng, Jinsheng; Turkeltaub, Peter E

    2016-01-01

    The neural mechanisms underlying recovery of language after left hemisphere stroke remain elusive. Although older evidence suggested that right hemisphere language homologues compensate for damage in left hemisphere language areas, the current prevailing theory suggests that right hemisphere engagement is ineffective or even maladaptive. Using a novel combination of support vector regression-based lesion-symptom mapping and voxel-based morphometry, we aimed to determine whether local grey matter volume in the right hemisphere independently contributes to aphasia outcomes after chronic left hemisphere stroke. Thirty-two left hemisphere stroke survivors with aphasia underwent language assessment with the Western Aphasia Battery-Revised and tests of other cognitive domains. High-resolution T1-weighted images were obtained in aphasia patients and 30 demographically matched healthy controls. Support vector regression-based multivariate lesion-symptom mapping was used to identify critical language areas in the left hemisphere and then to quantify each stroke survivor's lesion burden in these areas. After controlling for these direct effects of the stroke on language, voxel-based morphometry was then used to determine whether local grey matter volumes in the right hemisphere explained additional variance in language outcomes. In brain areas in which grey matter volumes related to language outcomes, we then compared grey matter volumes in patients and healthy controls to assess post-stroke plasticity. Lesion-symptom mapping showed that specific left hemisphere regions related to different language abilities. After controlling for lesion burden in these areas, lesion size, and demographic factors, grey matter volumes in parts of the right temporoparietal cortex positively related to spontaneous speech, naming, and repetition scores. Examining whether domain general cognitive functions might explain these relationships, partial correlations demonstrated that grey matter

  12. Right hemisphere grey matter structure and language outcomes in chronic left hemisphere stroke.

    PubMed

    Xing, Shihui; Lacey, Elizabeth H; Skipper-Kallal, Laura M; Jiang, Xiong; Harris-Love, Michelle L; Zeng, Jinsheng; Turkeltaub, Peter E

    2015-10-31

    The neural mechanisms underlying recovery of language after left hemisphere stroke remain elusive. Although older evidence suggested that right hemisphere language homologues compensate for damage in left hemisphere language areas, the current prevailing theory suggests that right hemisphere engagement is ineffective or even maladaptive. Using a novel combination of support vector regression-based lesion-symptom mapping and voxel-based morphometry, we aimed to determine whether local grey matter volume in the right hemisphere independently contributes to aphasia outcomes after chronic left hemisphere stroke. Thirty-two left hemisphere stroke survivors with aphasia underwent language assessment with the Western Aphasia Battery-Revised and tests of other cognitive domains. High-resolution T1-weighted images were obtained in aphasia patients and 30 demographically matched healthy controls. Support vector regression-based multivariate lesion-symptom mapping was used to identify critical language areas in the left hemisphere and then to quantify each stroke survivor's lesion burden in these areas. After controlling for these direct effects of the stroke on language, voxel-based morphometry was then used to determine whether local grey matter volumes in the right hemisphere explained additional variance in language outcomes. In brain areas in which grey matter volumes related to language outcomes, we then compared grey matter volumes in patients and healthy controls to assess post-stroke plasticity. Lesion-symptom mapping showed that specific left hemisphere regions related to different language abilities. After controlling for lesion burden in these areas, lesion size, and demographic factors, grey matter volumes in parts of the right temporoparietal cortex positively related to spontaneous speech, naming, and repetition scores. Examining whether domain general cognitive functions might explain these relationships, partial correlations demonstrated that grey matter

  13. Copper(I)-Catalyzed Asymmetric Desymmetrization through Inverse-Electron-Demand aza-Diels-Alder Reaction: Efficient Access to Tetrahydropyridazines Bearing a Unique α-Chiral Silane Moiety.

    PubMed

    Wei, Liang; Zhou, Yu; Song, Zhi-Min; Tao, Hai-Yan; Lin, Zhenyang; Wang, Chun-Jiang

    2017-04-11

    An unprecedented copper(I)-catalyzed asymmetric desymmetrization of 5-silylcyclopentadienes with in situ formed azoalkene was realized through an inverse-electron-demand aza-Diels-Alder reaction (IEDDA) pathway, in which 5-silylcyclopentadienes served as efficient enophiles. This new protocol provides a facile access to the biologically important heterocyclic tetrahydropyridazines containing a unique α-chiral silane motif and three adjoining stereogenic centers in generally good yield (up to 92 %) with exclusive regioselectivity, high diastereoselectivity (>20:1 diastereomeric ratio), and excellent enantioselectivity (up to 98 % enantiomeric excess). DFT calculations and control experiments further confirmed the proposed reaction mechanism.

  14. Bisadducts from the Diels-Alder Trapping of Bis(o-Xylenols) Photochemically Generated from 2,5-Dibenzoyl-p-xylene

    NASA Technical Reports Server (NTRS)

    Meador, Michael A.; Kinder, James D.; Kirby, James P.

    2003-01-01

    Photolysis of 2,5-dibenzoyl-p-xylene produces two discrete o-xylenols which undergo Diels-Alder cycloadditions with standard dienophiles, such as methyl acrylate, to produce 1,5-dihydroxy-1,5-diphenyl-l,2,3,4,5,6,7,8-octahydroanthracenes, 2a, in good yield (greater than 80%). The anti bisadduct crystallizes into hydrogen bonded stacks. Conversion of both syn- and anti-bisadducts to the corresponding anthracenes was achieved through the use of standard dehydration and aromatization chemistry.

  15. Ultra-high precision 40Ar/39Ar ages for Fish Canyon Tuff and Alder Creek Rhyolite sanidine: New dating standards required?

    NASA Astrophysics Data System (ADS)

    Phillips, D.; Matchan, E. L.

    2013-11-01

    The 40Ar/39Ar dating technique is a high precision (<0.1%) method with wide application to geological samples. However, the method is predicated on the availability of natural mineral standards of known age. Widely used 40Ar/39Ar standards include sanidine from the (ca. 28 Ma) Fish Canyon Tuff (FCT) and the (ca. 1.2 Ma) Alder Creek Rhyolite (ACR). Despite common usage, the ages of FCT and ACR sanidine have proven contentious, with reported values varying by >2%; well outside the ±0.1% aspiration of EARTHTIME (http://www.earth-time.org).

  16. Enantioselective synthesis of allenylenol silyl ethers via chiral lithium amide mediated reduction of ynenoyl silanes and their Diels-Alder reactions.

    PubMed

    Sasaki, Michiko; Kondo, Yasuhiro; Moto-ishi, Ta-ichi; Kawahata, Masatoshi; Yamaguchi, Kentaro; Takeda, Kei

    2015-03-06

    An enantioselective Meerwein-Ponndorf-Verley-type reduction of ynenoylsilanes by a chiral lithium amide followed by a Brook rearrangement and anti-mode protonation across conjugated 1,3-enynes provides allene derivatives bearing a 2-siloxyvinyl moiety in high enantioselectivity. The E/Z geometry of enol silyl ethers is controlled by the geometry of the starting enyne moiety. Thus, (E)- and (Z)-enol silyl ethers are obtained from (Z)- and (E)-ynenoylsilans, respectively. The 2-siloxyvinylallene products can participate in Diels-Alder reactions with reactive dienophiles such as PTAD, which can be achieved in a one-pot operation from ynenoylsilanes.

  17. The acyl nitroso Diels-Alder (ANDA) reaction of sorbate derivatives: an X-ray and 15N NMR study with an application to amino-acid synthesis.

    PubMed

    Bollans, Lee; Bacsa, John; Iggo, Jonathan A; Morris, Gareth A; Stachulski, Andrew V

    2009-11-07

    We present a study of the acyl nitroso Diels-Alder (ANDA) reaction of sorbate esters and sorbic alcohol derivatives, using alkoxycarbonyl nitroso dienophiles. An optimisation of the reaction conditions for ethyl sorbate is first presented, and the product is used in an efficient synthesis of 5-methylornithine. Structure-reactivity trends in sorbic alcohol (E,E-2,4-hexadien-1-ol) and its acylated analogues are then discussed. We present single-crystal X-ray structural proof for key adducts in both series and present in detail a novel HMBC/HSQC ((1)H-(15)N) criterion for ready distinction of regioisomers arising from such ANDA reactions.

  18. Lanthanide (III)-catalyzed enantioselective Diels-Alder reactions. Stereoselective synthesis of both enantiomers by using a single chiral source and a choice of achiral ligands

    SciTech Connect

    Kobayashi, Shu; Ishitani, Haruro )

    1994-05-04

    In this paper, we disclose a conceptually different approach to obtaining both enantiomers; choice of enatiofacial selectivity by use of the enatiomerically same chiral source and different achiral ligands. Both enantiomers of the Diels-Alder adducts between e-acyl-1,3-oxazolidin-2-ones and cyclopentadiene were prepared by chiral lanthanides(III)-catalyzed reactions using the same chiral source, (R)-(+)-binaphthol. It is noted that the chiral catalysts with reverse enantiofacial selectivities could be prepared by using the same chiral source and a choice of achiral ligands. 14 refs., 3 tabs.

  19. From enantiopure hydroxyaldehydes to complex heterocyclic scaffolds: development of domino Petasis/Diels-Alder and cross-metathesis/Michael addition reactions.

    PubMed

    Cannillo, Alexandre; Norsikian, Stéphanie; Tran Huu Dau, Marie-Elise; Retailleau, Pascal; Iorga, Bogdan I; Beau, Jean-Marie

    2014-09-15

    One-step assembly of hexahydroisoindole scaffolds by a sequence that combines the Petasis (borono-Mannich) and Diels-Alder reactions is described. The unique selectivity observed experimentally was confirmed by quantum calculations. The current method is applicable to a broad range of substrates, including free sugars, and holds significant potential to efficiently and stereoselectively build new heterocyclic structures. This easy and fast entry to functionalized polycyclic compounds can be pursued by further transformations, for example, additional ring closure by a cross-metathesis/Michael addition domino sequence.

  20. Tandem one-pot synthesis of flavans by recyclable silica-HClO4 catalyzed Knoevenagel condensation and [4 + 2]-Diels-Alder cycloaddition.

    PubMed

    Bharate, Sandip B; Mudududdla, Ramesh; Bharate, Jaideep B; Battini, Narsaiah; Battula, Satyanarayana; Yadav, Rammohan R; Singh, Baldev; Vishwakarma, Ram A

    2012-07-14

    An efficient one-pot multi-component synthesis of flavans using perchloric acid supported on silica as a recyclable heterogeneous catalyst has been described. This is the first report of direct one-step construction of a flavan skeleton from a phenolic precursor. The method involves a Knoevenagel-type condensation leading to in situ formation of transient O-quinone methide which further undergoes [4 + 2]-Diels-Alder cycloaddition with styrene to yield a flavan skeleton. The method provides easy access to a wide range of bio-active natural products viz. flavonoids, anthocyanins and catechins.

  1. Liquid-crystalline and electron-deficient coronene oligocarboxylic esters and imides by twofold benzogenic Diels-Alder reactions on perylenes.

    PubMed

    Alibert-Fouet, Sonia; Seguy, Isabelle; Bobo, Jean-François; Destruel, Pierre; Bock, Harald

    2007-01-01

    Alkyl esters, imides and imido-esters of coronene-tri-, -tetra- and -octacarboxylic acids are accessible by a twofold oxidative benzogenic Diels-Alder reaction. Alkyl acrylates add to perylene, and maleic alkyl imides react twice with perylene as well as with perylene-tetracarboxylic tetraesters. Coronenes substituted with a greatly variable number of electron-withdrawing substituents are thus accessible, and di- and tetraimide derivatives are shown to be very pronounced electron-acceptor materials. The tri- and tetraalkyl esters and imidoesters self-assemble into columnar liquid-crystalline phases.

  2. Comparative sensitivity of harbour and grey seals to several environmental contaminants using in vitro exposure.

    PubMed

    Dufresne, M M; Frouin, H; Pillet, S; Lesage, V; De Guise, S; Fournier, M

    2010-03-01

    In this study, we investigated the effects of cadmium chloride (CdCl(2)), mercury chloride (HgCl(2)), methylmercury chloride (CH(3)HgCl), and PCBs on lymphocyte proliferation in phocids. PBMCs isolated from harbour and grey seals were exposed in vitro to varying concentrations of contaminants. A reduction of viability occurred when cells were exposed to 10(-4)M HgCl(2) or CH(3)HgCl or to 50ppm of Aroclor 1254. In both grey and harbour seals, T-lymphocyte proliferation was suppressed when their cells were incubated with 5 x 10(-5)M CdCl(2) or 10(-4)M HgCl(2). An inhibition of proliferation occurred with CH(3)HgCl from 10(-6)M in grey seals and from 10(-5)M in harbour seals. In grey seals, Aroclor 1254 reduced lymphocyte proliferation at 15ppm. In both harbour and grey seals, CH(3)HgCl was ten times more immunotoxic that HgCl(2). From IC(50), chemicals were ranked in terms of toxicity as followed: CH(3)HgCl>CdCl(2)>HgCl(2)>Aroclor 1254.

  3. Relative Roles of Grey Squirrels, Supplementary Feeding, and Habitat in Shaping Urban Bird Assemblages

    PubMed Central

    Bonnington, Colin; Gaston, Kevin J.; Evans, Karl L.

    2014-01-01

    Non-native species are frequently considered to influence urban assemblages. The grey squirrel Sciurus carolinensis is one such species that is widespread in the UK and is starting to spread across Europe; it predates birds’ nests and can compete with birds for supplementary food. Using distance sampling across the urbanisation intensity gradient in Sheffield (UK) we test whether urban grey squirrels influence avian species richness and density through nest predation and competition for supplementary food sources. We also assess how urban bird assemblages respond to supplementary feeding. We find that grey squirrels slightly reduced the abundance of breeding bird species most sensitive to squirrel nest predation by reducing the beneficial impact of woodland cover. There was no evidence that grey squirrel presence altered relationships between supplementary feeding and avian assemblage structure. This may be because, somewhat surprisingly, supplementary feeding was not associated with the richness or density of wintering bird assemblages. These associations were positive during the summer, supporting advocacy to feed birds during the breeding season and not just winter, but explanatory capacity was limited. The amount of green space and its quality, assessed as canopy cover, had a stronger influence on avian species richness and population size than the presence of grey squirrels and supplementary feeding stations. Urban bird populations are thus more likely to benefit from investment in improving the availability of high quality habitats than controlling squirrel populations or increased investment in supplementary feeding. PMID:25338062

  4. Relative roles of grey squirrels, supplementary feeding, and habitat in shaping urban bird assemblages.

    PubMed

    Bonnington, Colin; Gaston, Kevin J; Evans, Karl L

    2014-01-01

    Non-native species are frequently considered to influence urban assemblages. The grey squirrel Sciurus carolinensis is one such species that is widespread in the UK and is starting to spread across Europe; it predates birds' nests and can compete with birds for supplementary food. Using distance sampling across the urbanisation intensity gradient in Sheffield (UK) we test whether urban grey squirrels influence avian species richness and density through nest predation and competition for supplementary food sources. We also assess how urban bird assemblages respond to supplementary feeding. We find that grey squirrels slightly reduced the abundance of breeding bird species most sensitive to squirrel nest predation by reducing the beneficial impact of woodland cover. There was no evidence that grey squirrel presence altered relationships between supplementary feeding and avian assemblage structure. This may be because, somewhat surprisingly, supplementary feeding was not associated with the richness or density of wintering bird assemblages. These associations were positive during the summer, supporting advocacy to feed birds during the breeding season and not just winter, but explanatory capacity was limited. The amount of green space and its quality, assessed as canopy cover, had a stronger influence on avian species richness and population size than the presence of grey squirrels and supplementary feeding stations. Urban bird populations are thus more likely to benefit from investment in improving the availability of high quality habitats than controlling squirrel populations or increased investment in supplementary feeding.

  5. Principle Study of Head Meridian Acupoint Massage to Stress Release via Grey Data Model Analysis

    PubMed Central

    Lee, Ya-Ting

    2016-01-01

    This paper presents the scientific study of the effectiveness and action principle of head meridian acupoint massage by applying the grey data model analysis approach. First, the head massage procedure for massaging the important head meridian acupuncture points including Taiyang, Fengfu, Tianzhu, Fengqi, and Jianjing is formulated in a standard manner. Second, the status of the autonomic nervous system of each subject is evaluated by using the heart rate variability analyzer before and after the head massage following four weeks. Afterward, the physiological factors of autonomic nerves are quantitatively analyzed by using the grey data modeling theory. The grey data analysis can point out that the status of autonomic nervous system is greatly improved after the massage. The order change of the grey relationship weighting of physiological factors shows the action principle of the sympathetic and parasympathetic nerves when performing head massage. In other words, the grey data model is able to distinguish the detailed interaction of the autonomic nervous system and the head meridian acupoint massage. Thus, the stress relaxing effect of massaging head meridian acupoints is proved, which is lacked in literature. The results can be a reference principle for massage health care in practice. PMID:26904144

  6. Grey matter networks in people at increased familial risk for schizophrenia.

    PubMed

    Tijms, Betty M; Sprooten, Emma; Job, Dominic; Johnstone, Eve C; Owens, David G C; Willshaw, David; Seriès, Peggy; Lawrie, Stephen M

    2015-10-01

    Grey matter brain networks are disrupted in schizophrenia, but it is still unclear at which point during the development of the illness these disruptions arise and whether these can be associated with behavioural predictors of schizophrenia. We investigated if single-subject grey matter networks were disrupted in a sample of people at familial risk of schizophrenia. Single-subject grey matter networks were extracted from structural MRI scans of 144 high risk subjects, 32 recent-onset patients and 36 healthy controls. The following network properties were calculated: size, connectivity density, degree, path length, clustering coefficient, betweenness centrality and small world properties. People at risk of schizophrenia showed decreased path length and clustering in mostly prefrontal and temporal areas. Within the high risk sample, the path length of the posterior cingulate cortex and the betweenness centrality of the left inferior frontal operculum explained 81% of the variance in schizotypal cognitions, which was previously shown to be the strongest behavioural predictor of schizophrenia in the study. In contrast, local grey matter volume measurements explained 48% of variance in schizotypy. The present results suggest that single-subject grey matter networks can quantify behaviourally relevant biological alterations in people at increased risk for schizophrenia before disease onset.

  7. Grey matter changes of the pain matrix in patients with burning mouth syndrome.

    PubMed

    Sinding, Charlotte; Gransjøen, Anne Mari; Schlumberger, Gina; Grushka, Miriam; Frasnelli, Johannes; Singh, Preet Bano

    2016-04-01

    Burning mouth syndrome (BMS) is characterized by a burning sensation in the mouth, usually in the absence of clinical and laboratory findings. Latest findings indicate that BMS could result from neuropathic trigeminal conditions. While many investigations have focused on the periphery, very few have examined possible central dysfunctions. To highlight changes of the central system of subjects with BMS, we analysed the grey matter concentration in 12 subjects using voxel-based morphometry. Data were compared with a control group (Ct). To better understand the brain mechanisms underlying BMS, the grey matter concentration of patients was also compared with those of dysgeusic patients (Dys). Dysgeusia is another oral dysfunction condition, characterized by a distorted sense of taste and accompanied by a reduced taste function. We found that a major part of the 'pain matrix' presented modifications of the grey matter concentration in subjects with BMS. Six regions out of eight were affected [anterior and posterior cingulate gyrus, lobules of the cerebellum, insula/frontal operculum, inferior temporal area, primary motor cortex, dorsolateral pre-frontal cortex (DLPFC)]. In the anterior cingulate gyrus, the lobules of the cerebellum, the inferior temporal lobe and the DLPFC, pain intensity correlated with grey matter concentration. Dys also presented changes in grey matter concentration but in different areas of the brain. Our results suggest that a deficiency in the control of pain could in part be a cause of BMS and that BMS and dysgeusia conditions are not linked to similar structural changes in the brain.

  8. Principle Study of Head Meridian Acupoint Massage to Stress Release via Grey Data Model Analysis.

    PubMed

    Lee, Ya-Ting

    2016-01-01

    This paper presents the scientific study of the effectiveness and action principle of head meridian acupoint massage by applying the grey data model analysis approach. First, the head massage procedure for massaging the important head meridian acupuncture points including Taiyang, Fengfu, Tianzhu, Fengqi, and Jianjing is formulated in a standard manner. Second, the status of the autonomic nervous system of each subject is evaluated by using the heart rate variability analyzer before and after the head massage following four weeks. Afterward, the physiological factors of autonomic nerves are quantitatively analyzed by using the grey data modeling theory. The grey data analysis can point out that the status of autonomic nervous system is greatly improved after the massage. The order change of the grey relationship weighting of physiological factors shows the action principle of the sympathetic and parasympathetic nerves when performing head massage. In other words, the grey data model is able to distinguish the detailed interaction of the autonomic nervous system and the head meridian acupoint massage. Thus, the stress relaxing effect of massaging head meridian acupoints is proved, which is lacked in literature. The results can be a reference principle for massage health care in practice.

  9. Molecular Design of a Chiral Brønsted Acid with Two Different Acidic Sites: Regio-, Diastereo-, and Enantioselective Hetero-Diels-Alder Reaction of Azopyridinecarboxylate with Amidodienes Catalyzed by Chiral Carboxylic Acid-Monophosphoric Acid.

    PubMed

    Momiyama, Norie; Tabuse, Hideaki; Noda, Hirofumi; Yamanaka, Masahiro; Fujinami, Takeshi; Yamanishi, Katsunori; Izumiseki, Atsuto; Funayama, Kosuke; Egawa, Fuyuki; Okada, Shino; Adachi, Hiroaki; Terada, Masahiro

    2016-09-07

    A chiral Brønsted acid containing two different acidic sites, chiral carboxylic acid-monophosphoric acid 1a, was designed to be a new and effective concept in catalytic asymmetric hetero-Diels-Alder reactions of azopyridinecarboxylate with amidodienes. The multipoint hydrogen-bonding interactions among the carboxylic acid, monophosphoric acid, azopyridinecarboxylate, and amidodiene achieved high catalytic and chiral efficiency, producing substituted 1,2,3,6-tetrahydropyridazines with excellent stereocontrol in a single step. This constitutes the first example of regio-, diastereo-, and enantioselective azo-hetero-Diels-Alder reactions by chiral Brønsted acid catalysis.

  10. Cerebellar grey-matter deficits, cannabis use and first-episode schizophrenia in adolescents and young adults.

    PubMed

    Cohen, Martin; Rasser, Paul E; Peck, Greg; Carr, Vaughan J; Ward, Philip B; Thompson, Paul M; Johnston, Patrick; Baker, Amanda; Schall, Ulrich

    2012-04-01

    Epidemiological data link adolescent cannabis use to psychosis and schizophrenia, but its contribution to schizophrenia neuropathology remains controversial. First-episode schizophrenia (FES) patients show regional cerebral grey- and white-matter changes as well as a distinct pattern of regional grey-matter loss in the vermis of the cerebellum. The cerebellum possesses a high density of cannabinoid type 1 receptors involved in the neuronal diversification of the developing brain. Cannabis abuse may interfere with this process during adolescent brain maturation leading to 'schizophrenia-like' cerebellar pathology. Magnetic resonance imaging and cortical pattern matching techniques were used to investigate cerebellar grey and white matter in FES patients with and without a history of cannabis use and non-psychiatric cannabis users. In the latter group we found lifetime dose-dependent regional reduction of grey matter in the right cerebellar lobules and a tendency for more profound grey-matter reduction in lobule III with younger age at onset of cannabis use. The overall regional grey-matter differences in cannabis users were within the normal variability of grey-matter distribution. By contrast, FES subjects had lower total cerebellar grey-matter:total cerebellar volume ratio and marked grey-matter loss in the vermis, pedunculi, flocculi and lobules compared to pair-wise matched healthy control subjects. This pattern and degree of grey-matter loss did not differ from age-matched FES subjects with comorbid cannabis use. Our findings indicate small dose-dependent effects of juvenile cannabis use on cerebellar neuropathology but no evidence of an additional effect of cannabis use on FES cerebellar grey-matter pathology.

  11. High-order solution methods for grey discrete ordinates thermal radiative transfer

    SciTech Connect

    Maginot, Peter G.; Ragusa, Jean C.; Morel, Jim E.

    2016-09-29

    This paper presents a solution methodology for solving the grey radiative transfer equations that is both spatially and temporally more accurate than the canonical radiative transfer solution technique of linear discontinuous finite element discretization in space with implicit Euler integration in time. We solve the grey radiative transfer equations by fully converging the nonlinear temperature dependence of the material specific heat, material opacities, and Planck function. The grey radiative transfer equations are discretized in space using arbitrary-order self-lumping discontinuous finite elements and integrated in time with arbitrary-order diagonally implicit Runge–Kutta time integration techniques. Iterative convergence of the radiation equation is accelerated using a modified interior penalty diffusion operator to precondition the full discrete ordinates transport operator.

  12. Gammaherpesvirus infection in a free-ranging eastern grey kangaroo (Macropus giganteus).

    PubMed

    Wilcox, R S; Vaz, P; Ficorilli, N P; Whiteley, P L; Wilks, C R; Devlin, J M

    2011-01-01

    A gammaherpesvirus was detected by polymerase chain reaction (PCR) in ocular, nasal and oropharyngeal swab samples collected from an adult free-ranging male eastern grey kangaroo (Macropus giganteus) with clinical signs of severe respiratory disease. This is the first time a gammaherpesvirus has been detected in a free-ranging macropod in Australia. The nucleotide sequence of a conserved region of the DNA polymerase gene of the detected virus showed a high degree of identity to a gammaherpesvirus recently detected in a zoological collection of eastern grey kangaroos in North America. The detection of this gammaherpesvirus in a free-ranging, native eastern grey kangaroo provides evidence that this species is a natural host.

  13. Grey situation group decision-making method based on prospect theory.

    PubMed

    Zhang, Na; Fang, Zhigeng; Liu, Xiaqing

    2014-01-01

    This paper puts forward a grey situation group decision-making method on the basis of prospect theory, in view of the grey situation group decision-making problems that decisions are often made by multiple decision experts and those experts have risk preferences. The method takes the positive and negative ideal situation distance as reference points, defines positive and negative prospect value function, and introduces decision experts' risk preference into grey situation decision-making to make the final decision be more in line with decision experts' psychological behavior. Based on TOPSIS method, this paper determines the weight of each decision expert, sets up comprehensive prospect value matrix for decision experts' evaluation, and finally determines the optimal situation. At last, this paper verifies the effectiveness and feasibility of the method by means of a specific example.

  14. Influence of landscape features on the location of grey heron Ardea cinerea colonies in Poland.

    PubMed

    Manikowska-Ślepowrońska, Brygida; Lazarus, Magdalena; Żółkoś, Katarzyna; Zbyryt, Adam; Kitowski, Ignacy; Jakubas, Dariusz

    We analysed hydrographic and habitat factors influencing the location of 207 colonies of the grey heron Ardea cinerea in Poland. We compared areas of particular habitats in three buffers around colonies (0-1, 0-10, 0-20km) among eight regions differing in their proportions of studied habitats. We found the highest inter-region dissimilarities in areas covered by water bodies (all scales) and pastures (0-1km). We recognized some indicator habitats characteristic of the majority (water bodies, pastures) or of some (seacoast, inland marshes, urbanized zone) regions. The habitat selectivity index showed that grey herons in buffer 0-1km preferred pastures and water bodies in seven regions and rivers in one subprovince. In buffer 0-10km, forests and urban zones were preferred in seven and five subprovinces, respectively. Our study revealed that both aquatic and non-aquatic habitats are important for the distribution of the grey heron colonies in Poland.

  15. Attenuation of brain grey matter volume in brachial plexus injury patients.

    PubMed

    Lu, Yechen; Liu, Hanqiu; Hua, Xuyun; Xu, Jian-Guang; Gu, Yu-Dong; Shen, Yundong

    2016-01-01

    Brachial plexus injury (BPI) causes functional changes in the brain, but the structural changes resulting from BPI remain unknown. In this study, we compared grey matter volume between nine BPI patients and ten healthy controls by means of voxel-based morphometry. This was the first study of cortical morphology in BPI. We found that brain regions including the cerebellum, anterior cingulate cortex, bilateral inferior, medial, superior frontal lobe, and bilateral insula had less grey matter in BPI patients. Most of the affected brain regions of BPI patients are closely related to motor function. We speculate that the loss of grey matter in multiple regions might be the neural basis of the difficulties in the motor rehabilitation of BPI patients. The mapping result might provide new target regions for interventions of motor rehabilitation.

  16. Membrane chemical reactor (MCR) combining photocatalysis and microfiltration for grey water treatment.

    PubMed

    Rivero, M J; Parsons, S A; Jeffrey, P; Pidou, M; Jefferson, B

    2006-01-01

    Urban water recycling is now becoming an important issue where water resources are becoming scarce. This paper looks at reusing grey water; the preference is treatment processes based on biological systems to remove the dissolved organic content. Here, an alternative process, photocatalysis is discussed as it is an attractive technology that could be well-suited for treating the recalcitrant organic compounds found in grey water. The photocatalytic process oxidises organic reactants at a catalyst surface in the presence of ultraviolet light. Given enough exposure time, organic compounds will be oxidized into CO2 and water. The best contact is achieved in a slurry reactor but a second step to separate and recover the catalyst is need. This paper discusses a new membrane chemical reactor (MCR) combining photocatalysis and microfiltration for grey water treatment.

  17. High-order solution methods for grey discrete ordinates thermal radiative transfer

    DOE PAGES

    Maginot, Peter G.; Ragusa, Jean C.; Morel, Jim E.

    2016-09-29

    This paper presents a solution methodology for solving the grey radiative transfer equations that is both spatially and temporally more accurate than the canonical radiative transfer solution technique of linear discontinuous finite element discretization in space with implicit Euler integration in time. We solve the grey radiative transfer equations by fully converging the nonlinear temperature dependence of the material specific heat, material opacities, and Planck function. The grey radiative transfer equations are discretized in space using arbitrary-order self-lumping discontinuous finite elements and integrated in time with arbitrary-order diagonally implicit Runge–Kutta time integration techniques. Iterative convergence of the radiation equation ismore » accelerated using a modified interior penalty diffusion operator to precondition the full discrete ordinates transport operator.« less

  18. The genealogy and genetic viability of reintroduced Yellowstone grey wolves.

    PubMed

    Vonholdt, Bridgett M; Stahler, Daniel R; Smith, Douglas W; Earl, Dent A; Pollinger, John P; Wayne, Robert K

    2008-01-01

    The recovery of the grey wolf in Yellowstone National Park is an outstanding example of a successful reintroduction. A general question concerning reintroduction is the degree to which genetic variation has been preserved and the specific behavioural mechanisms that enhance the preservation of genetic diversity and reduce inbreeding. We have analysed 200 Yellowstone wolves, including all 31 founders, for variation in 26 microsatellite loci over the 10-year reintroduction period (1995-2004). The population maintained high levels of variation (1995 H(0) = 0.69; 2004 H(0) = 0.73) with low levels of inbreeding (1995 F(IS) = -0.063; 2004 F(IS) = -0.051) and throughout, the population expanded rapidly (N(1995) = 21; N(2004) = 169). Pedigree-based effective population size ratios did not vary appreciably over the duration of population expansion (1995 N(e)/N(g) = 0.29; 2000 N(e)/N(g) = 0.26; 2004 N(e)/N(g) = 0.33). We estimated kinship and found only two of 30 natural breeding pairs showed evidence of being related (average r = -0.026, SE = 0.03). We reconstructed the genealogy of 200 wolves based on genetic and field data and discovered that they avoid inbreeding through a wide variety of behavioural mechanisms including absolute avoidance of breeding with related pack members, male-biased dispersal to packs where they breed with nonrelatives, and female-biased subordinate breeding. We documented a greater diversity of such population assembly patterns in Yellowstone than previously observed in any other natural wolf population. Inbreeding avoidance is nearly absolute despite the high probability of within-pack inbreeding opportunities and extensive interpack kinship ties between adjacent packs. Simulations showed that the Yellowstone population has levels of genetic variation similar to that of a population managed for high variation and low inbreeding, and greater than that expected for random breeding within packs or across the entire breeding pool. Although short

  19. Pulsed Electric Propulsion Thrust Stand Calibration Method

    NASA Technical Reports Server (NTRS)

    Wong, Andrea R.; Polzin, Kurt A.; Pearson, J. Boise

    2011-01-01

    The evaluation of the performance of any propulsion device requires the accurate measurement of thrust. While chemical rocket thrust is typically measured using a load cell, the low thrust levels associated with electric propulsion (EP) systems necessitate the use of much more sensitive measurement techniques. The design and development of electric propulsion thrust stands that employ a conventional hanging pendulum arm connected to a balance mechanism consisting of a secondary arm and variable linkage have been reported in recent publications by Polzin et al. These works focused on performing steady-state thrust measurements and employed a static analysis of the thrust stand response. In the present work, we present a calibration method and data that will permit pulsed thrust measurements using the Variable Amplitude Hanging Pendulum with Extended Range (VAHPER) thrust stand. Pulsed thrust measurements are challenging in general because the pulsed thrust (impulse bit) occurs over a short timescale (typically 1 micros to 1 millisecond) and cannot be resolved directly. Consequently, the imparted impulse bit must be inferred through observation of the change in thrust stand motion effected by the pulse. Pulsed thrust measurements have typically only consisted of single-shot operation. In the present work, we discuss repetition-rate pulsed thruster operation and describe a method to perform these measurements. The thrust stand response can be modeled as a spring-mass-damper system with a repetitive delta forcing function to represent the impulsive action of the thruster.

  20. Musical training intensity yields opposite effects on grey matter density in cognitive versus sensorimotor networks.

    PubMed

    James, Clara E; Oechslin, Mathias S; Van De Ville, Dimitri; Hauert, Claude-Alain; Descloux, Céline; Lazeyras, François

    2014-01-01

    Using optimized voxel-based morphometry, we performed grey matter density analyses on 59 age-, sex- and intelligence-matched young adults with three distinct, progressive levels of musical training intensity or expertise. Structural brain adaptations in musicians have been repeatedly demonstrated in areas involved in auditory perception and motor skills. However, musical activities are not confined to auditory perception and motor performance, but are entangled with higher-order cognitive processes. In consequence, neuronal systems involved in such higher-order processing may also be shaped by experience-driven plasticity. We modelled expertise as a three-level regressor to study possible linear relationships of expertise with grey matter density. The key finding of this study resides in a functional dissimilarity between areas exhibiting increase versus decrease of grey matter as a function of musical expertise. Grey matter density increased with expertise in areas known for their involvement in higher-order cognitive processing: right fusiform gyrus (visual pattern recognition), right mid orbital gyrus (tonal sensitivity), left inferior frontal gyrus (syntactic processing, executive function, working memory), left intraparietal sulcus (visuo-motor coordination) and bilateral posterior cerebellar Crus II (executive function, working memory) and in auditory processing: left Heschl's gyrus. Conversely, grey matter density decreased with expertise in bilateral perirolandic and striatal areas that are related to sensorimotor function, possibly reflecting high automation of motor skills. Moreover, a multiple regression analysis evidenced that grey matter density in the right mid orbital area and the inferior frontal gyrus predicted accuracy in detecting fine-grained incongruities in tonal music.

  1. Sensory migraine aura is not associated with structural grey matter abnormalities.

    PubMed

    Hougaard, Anders; Amin, Faisal Mohammad; Arngrim, Nanna; Vlachou, Maria; Larsen, Vibeke Andrée; Larsson, Henrik B W; Ashina, Messoud

    2016-01-01

    Migraine with aura (MA) is characterized by cortical dysfunction. Frequent aura attacks may alter cerebral cortical structure in patients, or structural grey matter abnormalities may predispose MA patients to aura attacks. In the present study we aimed to investigate cerebral grey matter structure in a large group of MA patients with and without sensory aura (i.e. gradually developing, transient unilateral sensory disturbances). We included 60 patients suffering from migraine with typical visual aura and 60 individually age and sex-matched controls. Twenty-nine of the patients additionally experienced sensory aura regularly. We analysed high-resolution structural MR images using two complimentary approaches and compared patients with and without sensory aura. Patients were also compared to controls. We found no differences of grey matter density or cortical thickness between patients with and without sensory aura and no differences for the cortical visual areas between patients and controls. The somatosensory cortex was thinner in patients (1.92 mm vs. 1.96 mm, P = 0.043) and the anterior cingulate cortex of patients had a decreased grey matter density (P = 0.039) compared to controls. These differences were not correlated to the clinical characteristics. Our results suggest that sensory migraine aura is not associated with altered grey matter structure and that patients with visual aura have normal cortical structure of areas involved in visual processing. The observed decreased grey matter volume of the cingulate gyrus in patients compared to controls have previously been reported in migraine with and without aura, but also in a wide range of other neurologic and psychiatric disorders. Most likely, this finding reflects general bias between patients and healthy controls.

  2. The Effects of Meditation on Grey Matter Atrophy and Neurodegeneration: A Systematic Review.

    PubMed

    Last, Nicole; Tufts, Emily; Auger, Leslie E

    2017-01-01

    The present systematic review is based on the premise that a variety of neurodegenerative diseases are accompanied by grey matter atrophy in the brain and meditation may impact this. Given that age is a major risk factor for many of these progressive and neurodegenerative diseases and that the percentage of the population over the age of 65 is quickly increasing, there is an obvious need for prompt treatment and prevention advances in research. As there is currently no cure for Alzheimer's disease and other neurodegenerative diseases, many are seeking non-pharmacological treatment options in attempts to offset the disease-related cognitive and functional declines. On the basis of a growing body of research suggesting that meditation is effective in increasing grey matter volume in healthy participants, this paper systematically reviewed the literature regarding the effects of meditation on restoring grey matter volume in healthy individuals and those affected by neurodegeneration. This review searched PubMed, CINAHL, and APA PsycNET to identify original studies that included MRI imaging to measure grey matter volume in meditators and post-mindfulness-based intervention participants compared to controls. Thirteen studies were considered eligible for review and involved a wide variety of meditation techniques and included participants with and without cognitive impairment. All studies reported significant increases in grey matter volume in the meditators/intervention group, albeit in assorted regions of the brain. Limited research exists on the mechanisms through which meditation affects disease-related neurodegeneration, but preliminary evidence suggests that it may offset grey matter atrophy.

  3. Grey matter correlates of susceptibility to scams in community-dwelling older adults.

    PubMed

    Duke Han, S; Boyle, Patricia A; Yu, Lei; Arfanakis, Konstantinos; James, Bryan D; Fleischman, Debra A; Bennett, David A

    2016-06-01

    Susceptibility to scams is a significant issue among older adults, even among those with intact cognition. Age-related changes in brain macrostructure may be associated with susceptibility to scams; however, this has yet to be explored. Based on previous work implicating frontal and temporal lobe functioning as important in decision making, we tested the hypothesis that susceptibility to scams is associated with smaller grey matter volume in frontal and temporal lobe regions in a large community-dwelling cohort of non-demented older adults. Participants (N = 327, mean age = 81.55, mean education = 15.30, 78.9 % female) completed a self-report measure used to assess susceptibility to scams and an MRI brain scan. Results indicated an inverse association between overall grey matter and susceptibility to scams in models adjusted for age, education, and sex; and in models further adjusted for cognitive function. No significant associations were observed for white matter, cerebrospinal fluid, or total brain volume. Models adjusted for age, education, and sex revealed seven clusters showing smaller grey matter in the right parahippocampal/hippocampal/fusiform, left middle temporal, left orbitofrontal, right ventromedial prefrontal, right middle temporal, right precuneus, and right dorsolateral prefrontal regions. In models further adjusted for cognitive function, results revealed three significant clusters showing smaller grey matter in the right parahippocampal/hippocampal/fusiform, right hippocampal, and right middle temporal regions. Lower grey matter concentration in specific brain regions may be associated with susceptibility to scams, even after adjusting for cognitive ability. Future research is needed to determine whether grey matter reductions in these regions may be a biomarker for susceptibility to scams in old age.

  4. Dissociated grey matter changes with prolonged addiction and extended abstinence in cocaine users.

    PubMed

    Connolly, Colm G; Bell, Ryan P; Foxe, John J; Garavan, Hugh

    2013-01-01

    Extensive evidence indicates that current and recently abstinent cocaine abusers compared to drug-naïve controls have decreased grey matter in regions such as the anterior cingulate, lateral prefrontal and insular cortex. Relatively little is known, however, about the persistence of these deficits in long-term abstinence despite the implications this has for recovery and relapse. Optimized voxel based morphometry was used to assess how local grey matter volume varies with years of drug use and length of abstinence in a cross-sectional study of cocaine users with various durations of abstinence (1-102 weeks) and years of use (0.3-24 years). Lower grey matter volume associated with years of use was observed for several regions including anterior cingulate, inferior frontal gyrus and insular cortex. Conversely, higher grey matter volumes associated with abstinence duration were seen in non-overlapping regions that included the anterior and posterior cingulate, insular, right ventral and left dorsal prefrontal cortex. Grey matter volumes in cocaine dependent individuals crossed those of drug-naïve controls after 35 weeks of abstinence, with greater than normal volumes in users with longer abstinence. The brains of abstinent users are characterized by regional grey matter volumes, which on average, exceed drug-naïve volumes in those users who have maintained abstinence for more than 35 weeks. The asymmetry between the regions showing alterations with extended years of use and prolonged abstinence suggest that recovery involves distinct neurobiological processes rather than being a reversal of disease-related changes. Specifically, the results suggest that regions critical to behavioral control may be important to prolonged, successful, abstinence.

  5. The periaqueductal grey area and the cardiovascular system.

    PubMed

    Green, A L; Wang, S; Owen, S L F; Aziz, T Z

    2007-01-01

    In this chapter, we report that blood pressure can be increased or decreased depending on whether an electrode is in ventral or dorsal PAG. We also describe that it is theoretically possible to treat orthostatic hypotension. These are exciting developments not only because they provide an example of direct translational research from animal research to humans but also because they highlight a potential for future clinical therapies. The control of essential hypertension without drugs is attractive because of the side effects of medication such as precipitation of heart failure [10]. Similarly, drug treatment of orthostatic hypotension cannot differentiate between the supine and standing positions and can therefore lead to nocturnal hypertension [22, 29]. A stimulator could be turned off at night or contain a mercury switch that reacts to posture.

  6. The impact of beetle-induced conifer death on stand-scale canopy snow interception

    NASA Astrophysics Data System (ADS)

    Pugh, E. T.; Small, E. E.

    2011-12-01

    Snow that falls on a forest either passes through the canopy to the ground or is intercepted by the canopy on needles, branches or bark. The interception of snowfall in forest canopies impacts the water budget because intercepted snow is more likely to sublimate than subcanopy snow. Because forest canopy characteristics are a primary control of canopy snow interception, which in turn controls subcanopy snow accumulation, reductions in canopy density have important implications for snow accumulation on the forest floor. Forest structure can be drastically and rapidly altered by forest disturbance, such as insect attack, wildfire and blowdown. Here, we look at the impact that changing forest characteristics associated with beetle infestation have on canopy snow interception. The mountain pine beetle is currently impacting more than 100,000 km2 of pine forest in western North America. Trees killed by bark beetles eventually lose the majority of their canopy material. We hypothesize that tree death significantly reduces available interception platforms, leading to greater subcanopy snow accumulation than pre-infestation conditions. These potential impacts on snow accumulation are especially important for water resources in the western U.S., where the hydrologic cycle is dominated by snowmelt. We test this hypothesis using extensive data collected from adjacent living and grey phase dead stands. We employ multiple methods to measure canopy snow interception, at both the storm- and season-scales. During the winter of 2011, we made more than 10,000 spatially distributed measurements of subcanopy snow accumulation in three living and two dead lodgepole pine stands as well as three clearings. Measurements were made daily as well as immediately prior to and following storm events, allowing us to calculate storm-scale canopy interception. Interception is estimated by comparing subcanopy snow accumulation in clearings and forests. Additionally, by taking repeated daily

  7. Reactivity of Single-Walled Carbon Nanotubes in the Diels-Alder Cycloaddition Reaction: Distortion-Interaction Analysis along the Reaction Pathway.

    PubMed

    Li, Yingzi; Osuna, Sílvia; Garcia-Borràs, Marc; Qi, Xiaotian; Liu, Song; Houk, Kendall N; Lan, Yu

    2016-08-26

    Diels-Alder cycloaddition is one of the most powerful tools for the functionalization of single-walled carbon nanotubes (SWCNTs). Density functional theory at the B3-LYP level of theory has been used to investigate the reactivity of different-diameter SWCNTs (4-9,5) in Diels-Alder reactions with 1,3-butadiene; the reactivity was found to decrease with increasing SWCNT diameter. Distortion/interaction analysis along the whole reaction pathway was found to be a better way to explore the reactivity of this type of reaction. The difference in interaction energy along the reaction pathway is larger than that of the corresponding distortion energy. However, the distortion energy plots for these reactions show the same trend. Therefore, the formation of the transition state can be determined from the interaction energy. A lower interaction energy leads to an earlier transition state, which indicates a lower activation energy. The computational results also indicate that the original distortion of the SWCNTs leads to an increase in the reactivity of the SWCNTs.

  8. Inverse Electron Demand Diels–Alder Reactions of 1,2,3-Triazines: Pronounced Substituent Effects on Reactivity and Cycloaddition Scope

    PubMed Central

    Anderson, Erin D.; Boger, Dale L.

    2011-01-01

    A systematic study of the inverse electron demand Diels–Alder reactions of 1,2,3-triazines is disclosed, including an examination of the impact of a C5 substituent. Such substituents were found to exhibit a remarkable impact on the cycloaddition reactivity of the 1,2,3-triazine without altering, and perhaps even enhancing, the intrinsic cycloaddition regioselectivity. The study revealed that not only may the reactivity be predictably modulated by a C5 substituent (R = CO2Me > Ph > H), but that the impact is of a magnitude to convert 1,2,3-triazine (1) and its modest cycloaddition scope into a heterocyclic azadiene system with a reaction scope that portends extensive synthetic utility, expanding the range of participating dienophiles. Significantly, the studies define a now powerful additional heterocyclic azadiene, complementary to the isomeric 1,2,4-triazines and 1,3,5-triazines, capable of dependable participation in inverse electron demand Diels–Alder reactions, extending the number of complementary heterocyclic ring systems accessible with implementation of the methodology. PMID:21736324

  9. A Diels-Alder modulated approach to control and sustain the release of dexamethasone and induce osteogenic differentiation of human mesenchymal stem cells.

    PubMed

    Koehler, Kenneth C; Alge, Daniel L; Anseth, Kristi S; Bowman, Christopher N

    2013-05-01

    We report a new approach to controlled drug release based upon exploiting the dynamic equilibrium that exists between Diels-Alder reactants and products, demonstrating the release of a furan containing dexamethasone peptide (dex-KGPQG-furan) from a maleimide containing hydrogel. Using a reaction-diffusion model, the release kinetics were tuned to achieve sustained concentrations conducive to osteogenic differentiation of human mesenchymal stem cells (hMSCs). Efficacy was first demonstrated in a 2D culture model, in which dexamethasone release induced significant increases in alkaline phosphatase (ALP) activity and mineral deposition in hMSCs compared to a dexamethasone-free treatment. The results were similar to that observed with a soluble dexamethasone treatment. More dramatic differences were observed in 3D culture, where co-encapsulation of a dexamethasone releasing hydrogel depot within an hMSC-laden extracellular matrix mimetic poly(ethylene glycol) hydrogel resulted in a local and robust osteogenic differentiation. ALP activity reached levels that were up to six times higher than the dexamethasone free treatment. Interestingly, at 5 and 10 day time points, the ALP activity exceeded the dexamethasone positive control, suggesting a potential benefit of sustained release in 3D culture. After 21 days, substantial mineralization comparable to the positive control was also observed in the hydrogels. Collectively, these results demonstrate Diels-Alder modulated release as an effective and versatile new platform for controlled drug delivery that may prove especially beneficial for sustaining the release of low molecular weight molecules in hydrogel systems.

  10. Regioselective Inverse Electron Demand Diels-Alder Reactions of N-Acyl 6-Amino-3-(methylthio)-1,2,4,5-tetrazines.

    PubMed

    Boger, Dale L.; Schaum, Robert P.; Garbaccio, Robert M.

    1998-09-04

    The regioselective inverse electron demand Diels-Alder reactions of 6-[(tert-butyloxycarbonyl)amino]-3-(methylthio)-1,2,4,5-tetrazine (2), 6-(acetylamino)-3-(methylthio)-1,2,4,5-tetrazine (3), and 6-(benzyloxycarbonyl)amino-3-(methylthio)-1,2,4,5-tetrazine (4) are disclosed. All three underwent regioselective [4 + 2] cycloaddition with electron-rich dienophiles to form the corresponding functionalized 1,2-diazines in excellent yields. An order of reactivity with electron-rich dienophiles was observed with both 2 and 3 being more reactive than 3,6-bis(methylthio)-1,2,4,5-tetrazine (1, i.e. 3 > 2 > 1), and both 3 and 4 were shown to be more robust than 2 at the higher temperatures necessary for [4 + 2] cycloaddition with less reactive dienophiles. The cycloaddition regioselectivity is consistent with the polarization of the diene and the ability of the methylthio group to stabilize a partial negative charge at C-3, and the N-acylamino group to stabilize a partial positive charge at C-6. While intermolecular reactions of unactivated alkynes either did not proceed or required high temperatures and long reaction times, intramolecular Diels-Alder reactions utilizing tethered unactivated acetylenes led to five- and six-membered bicyclic 1,2-diazines under mild conditions.

  11. Antibiotic resistance in primary care in Austria - a systematic review of scientific and grey literature

    PubMed Central

    2011-01-01

    Background Antibiotic resistance is an increasing challenge for health care services worldwide. While up to 90% of antibiotics are being prescribed in the outpatient sector recommendations for the treatment of community-acquired infections are usually based on resistance findings from hospitalized patients. In context of the EU-project called "APRES - the appropriateness of prescribing antibiotic in primary health care in Europe with respect to antibiotic resistance" it was our aim to gain detailed information about the resistance data from Austria in both the scientific and the grey literature. Methods A systematic review was performed including scientific and grey literature published between 2000 and 2010. Inclusion and exclusion criteria were defined and the review process followed published recommendations. Results Seventeen scientific articles and 23 grey literature documents could be found. In contrast to the grey literature, the scientific publications describe only a small part of the resistance situation in the primary health care sector in Austria. Merely half of these publications contain data from the ambulatory sector exclusively but these data are older than ten years, are very heterogeneous concerning the observed time period, the number and origin of the isolates and the kind of bacteria analysed. The grey literature yields more comprehensive and up-to-date information of the content of interest. These sources are available in German only and are not easily accessible. The resistance situation described in the grey literature can be summarized as rather stable over the last two years. For Escherichia coli e.g. the highest antibiotic resistance rates can be seen with fluorochiniolones (19%) and trimethoprim/sulfamethoxazole (27%). Conclusion Comprehensive and up-to-date antibiotic resistance data of different pathogens isolated from the community level in Austria are presented. They could be found mainly in the grey literature, only few are

  12. Induction hardening treatment and simulation for a grey cast iron used in engine cylinder liners

    NASA Astrophysics Data System (ADS)

    Castellanos-Leal, E. L.; Miranda, D. A.; Coy, A. E.; Barrero, J. G.; González, J. A.; Vesga Rueda, O. P.

    2017-01-01

    In this research, a technical study of induction hardening in a grey cast iron used in engine cylinder liners manufactured by LAVCO Ltda., a Colombian foundry company, was carried out. Metallurgical parameters such as austenitization temperature, cooling rate, and quenching severity were determined. These factors are exclusively dependent on chemical composition and initial microstructure of grey cast iron. Simulations of induction heating through finite elements method were performed and, the most appropriate experimental conditions to achieve the critical transformation temperature was evaluated to reach a proper surface hardening on the piece. Preliminary results revealed an excellent approximation between simulation and heating test performed with a full bridge inverter voltage adapted with local technology.

  13. Beyond PubMed: Searching the “Grey Literature” for Clinical Trial Results

    PubMed Central

    2014-01-01

    Clinical trial results have been traditionally communicated through the publication of scholarly reports and reviews in biomedical journals. However, this dissemination of information can be delayed or incomplete, making it difficult to appraise new treatments, or in the case of missing data, evaluate older interventions. Going beyond the routine search of PubMed, it is possible to discover additional information in the “grey literature.” Examples of the grey literature include clinical trial registries, patent databases, company and industrywide repositories, regulatory agency digital archives, abstracts of paper and poster presentations on meeting/congress websites, industry investor reports and press releases, and institutional and personal websites. PMID:25337445

  14. Skeletal deformities and mortality in grey herons (Ardea cinerea) at Besthorpe heronry, Nottinghamshire.

    PubMed

    Feltrer, Y; Draper, E R C; Perkins, M; Cunningham, A A

    2006-10-14

    Dead and sick grey heron chicks with multiple fractures of the leg and wing bones and/or bone deformities have been reported at Besthorpe Nature Reserve heronry in north Nottinghamshire since 1996. Forty-five grey heron carcases were examined, 35 from the Besthorpe colony and 10 from other colonies where bone disease was not known to occur. On the basis of the results of radiological studies, postmortem examinations, peripheral quantitative computed tomography scanning and four-point bending tests, it was concluded that the skeletal abnormalities were probably due to metabolic bone disease.

  15. Extermination and recovery of red wolf and grey wolf in the contiguous United States

    USGS Publications Warehouse

    Phillips, Michael K.; Bangs, Edward E.; Mech, L. David; Kelly, Brian T.; Fazio, Buddy B.; Macdonald, David W.; Sillero-Zubiri, Claudio

    2004-01-01

    About 150 years ago, the grey wolf (Canis lupus) was distributed throughout the contiguous United States, except for in southeastern US from central Texas to the Atlantic coast, where the red wolf (Canis rufus) occurred. Conflict with agricultural interests resulted in government-supported eradication campaigns beginning in colonial Massachusetts in 1630. Over the next 300 years, the campaigns were extended throughout the US resulting in the near extermination of both species. In recent decades, efforts to recover the red and grey wolf were carried out. This chapter summarizes extermination and recovery efforts for both species in the contiguous US.

  16. Osteoblastic osteosarcoma in a Grey Mouse Lemur (Microcebus murinus) - short communication.

    PubMed

    Liptovszky, Mátyás; Perge, Edina; Molnár, Viktor; Sós, Endre

    2011-12-01

    The Grey Mouse Lemur (Microcebus murinus) is a nocturnal lemur species that lives only in Madagascar. It is one of the most abundant lemur species and its native populations are not endangered, but animals belonging to this species are rarely exhibited in zoos. While tumours are quite frequently described in other primates, there are very few publications about neoplasia in lemurs. In this case report we describe a mandibular osteoblastic osteosarcoma in a Grey Mouse Lemur (Microcebus murinus). To the best of the authors' knowledge, this is the first scientific article describing osteosarcoma in a prosimian and also reporting a tumour in the mandible in this taxon.

  17. Beyond PubMed: Searching the "Grey Literature" for Clinical Trial Results.

    PubMed

    Citrome, Leslie

    2014-07-01

    Clinical trial results have been traditionally communicated through the publication of scholarly reports and reviews in biomedical journals. However, this dissemination of information can be delayed or incomplete, making it difficult to appraise new treatments, or in the case of missing data, evaluate older interventions. Going beyond the routine search of PubMed, it is possible to discover additional information in the "grey literature." Examples of the grey literature include clinical trial registries, patent databases, company and industrywide repositories, regulatory agency digital archives, abstracts of paper and poster presentations on meeting/congress websites, industry investor reports and press releases, and institutional and personal websites.

  18. Standing waves in fiber-optic interferometers.

    PubMed

    de Haan, V; Santbergen, R; Tijssen, M; Zeman, M

    2011-10-10

    A study is presented giving the response of three types of fiber-optic interferometers by which a standing wave through an object is investigated. The three types are a Sagnac, Mach-Zehnder and Michelson-Morley interferometer. The response of the Mach-Zehnder interferometer is similar to the Sagnac interferometer. However, the Sagnac interferometer is much harder to study because of the fact that one input port and output port coincide. Further, the Mach-Zehnder interferometer has the advantage that the output ports are symmetric, reducing the systematic effects. Examples of standing wave light absorption in several simple objects are given. Attention is drawn to the influence of standing waves in fiber-optic interferometers with weak-absorbing layers incorporated. A method is described for how these can be theoretically analyzed and experimentally measured. Further experiments are needed for a thorough comparison between theory and experiment.

  19. Torsional thrust stand for characterization of microthrusters

    NASA Astrophysics Data System (ADS)

    Cheah, K. H.; Low, K. S.

    2016-10-01

    This paper describes the setup of a precise thrust stand based on torsional pendulum design for characterizing the performance of microthrusters. Calibration has been carried out by using an improved version of electrostatic calibrator, which produces a wide range of accurate and repeatable calibration force. After the calibration, the thrust stand can resolve constant force from 40μN to 3.4mN and impulse bit from 7μNs to 340μNs. The usefulness of the thrust stand has been demonstrated by measuring the performance of two different microthrusters: a pulsed plasma thruster that produces impulse bit of 23.15μNs and a vaporizing liquid microthruster that produces steady state thrust of 633.5μN.

  20. Standing sausage modes in curved coronal slabs

    NASA Astrophysics Data System (ADS)

    Pascoe, D. J.; Nakariakov, V. M.

    2016-09-01

    Context. Magnetohydrodynamic waveguides such as dense coronal loops can support standing modes. The ratios of the periods of oscillations for different longitudinal harmonics depend on the dispersive nature of the waveguide and so may be used as a seismological tool to determine coronal parameters. Aims: We extend models of standing sausage modes in low β coronal loops to include the effects of loop curvature. The behaviour of standing sausage modes in this geometry is used to explain the properties of observed oscillations that cannot be accounted for using straight loop models. Methods: We perform 2D numerical simulations of an oscillating coronal loop, modelled as a dense slab embedded in a potential magnetic field. The loop is field-aligned and so experiences expansion with height in addition to being curved. Standing sausage modes are excited by compressive perturbations of the loop and their properties are studied. Results: The spatial profiles of standing sausage modes are found to be modified by the expanding loop geometry typical for flaring loops and modelled by a potential magnetic field in our simulations. Longitudinal harmonics of order n > 1 have anti-nodes that are shifted towards the loop apex and the amplitude of anti-nodes near the loop apex is smaller than those near the loop footpoints. Conclusions: We find that the observation of standing sausage modes by the Nobeyama Radioheliograph in a flaring coronal loop on 12 January 2000 is consistent with interpretation in terms of the global mode (n = 1) and third harmonic (n = 3). This interpretation accounts for the period ratio and spatial structure of the observed oscillations.