Physical Training and Activity in People With Diabetic Peripheral Neuropathy: Paradigm Shift.

Science.gov (United States)

Kluding, Patricia M; Bareiss, Sonja K; Hastings, Mary; Marcus, Robin L; Sinacore, David R; Mueller, Michael J

2017-01-01

Diabetic peripheral neuropathy (DPN) occurs in more than 50% of people with diabetes and is an important risk factor for skin breakdown, amputation, and reduced physical mobility (ie, walking and stair climbing). Although many beneficial effects of exercise for people with diabetes have been well established, few studies have examined whether exercise provides comparable benefits to people with DPN. Until recently, DPN was considered to be a contraindication for walking or any weight-bearing exercise because of concerns about injuring a person's insensitive feet. These guidelines were recently adjusted, however, after research demonstrated that weight-bearing activities do not increase the risk of foot ulcers in people who have DPN but do not have severe foot deformity. Emerging research has revealed positive adaptations in response to overload stress in these people, including evidence for peripheral neuroplasticity in animal models and early clinical trials. This perspective article reviews the evidence for peripheral neuroplasticity in animal models and early clinical trials, as well as adaptations of the integumentary system and the musculoskeletal system in response to overload stress. These positive adaptations are proposed to promote improved function in people with DPN and to foster the paradigm shift to including weight-bearing exercise for people with DPN. This perspective article also provides specific assessment and treatment recommendations for this important, high-risk group. © 2017 American Physical Therapy Association.

Atomic force microscopy of torus-bearing pit membranes

Science.gov (United States)

Roland R. Dute; Thomas Elder

2011-01-01

Atomic force microscopy was used to compare the structures of dried, torus-bearing pit membranes from four woody species, three angiosperms and one gymnosperm. Tori of Osmanthus armatus are bipartite consisting of a pustular zone overlying parallel sets of microfibrils that form a peripheral corona. Microfibrils of the corona form radial spokes as they traverse the...

Rag Deletion in Peripheral T Cells Blocks TCR Revision

Science.gov (United States)

Hale, J. Scott; Ames, Kristina T.; Boursalian, Tamar E.; Fink, Pamela J.

2010-01-01

Mature CD4+Vβ5+ T cells that recognize a peripherally expressed endogenous superantigen are tolerized either by deletion or T cell receptor (TCR) revision. In Vβ5 transgenic mice, this latter tolerance pathway results in the appearance of CD4+Vβ5−TCRβ+ T cells, coinciding with Rag1, Rag2, and TdT expression and the accumulation of Vβ-DJβ recombination intermediates in peripheral CD4+ T cells. Because post-thymic RAG-dependent TCR rearrangement has remained controversial, we sought to definitively determine whether TCR revision is an extrathymic process that occurs in mature peripheral T cells. We now show that Rag deletion in post-positive selection T cells in Vβ5 transgenic mice blocks TCR revision in vivo, and that mature peripheral T cells sorted to remove cells bearing endogenous TCRβ chains can express newly generated TCRβ molecules in adoptive hosts. These findings unambiguously demonstrate post-thymic, RAG-dependent TCR rearrangement and define TCR revision as a tolerance pathway that targets mature peripheral CD4+ T cells. PMID:20435935

[Changes and significance of peripheral blood platelet count in tumor shrinkage induced by a low dose of CTX in T739 mice].

Science.gov (United States)

Li, Mo-lin; Jia, Yu-jie; Jiang, Miao-na; Shu, Xiao-hong; Li, Chuan-gang

2008-06-01

To establish a mouse model for BTT739 tumor-bearing mice cured by a low dose of cyclophosphamide (CTX). And then to observe the dynamic changes and significance of peripheral blood counts especially blood platelet count during tumor shrinkage induced by a low dose of CTX in T739 mice. Mouse bladder carcinoma tissues were inoculated subcutaneously into T739 mice. Seven days later, different doses of CTX or the same volume of NS were administered intraperitoneally to treat these tumor-bearing T739 mice. Tumor sizes were observed and recorded subsequently to find out the minimal dose of CTX that could cure most of these tumor-bearing mice. Then another 12 tumor-bearing mice were randomly divided into 15 mg/kg CTX treatment group and control group. Blood samples were obtained from orbital venous sinus on different times after CTX treatment. Complete blood counts were performed and the relationship between peripheral blood platelet counts and tumor shrinkage was analyzed. Within 2 weeks after CTX treatment, the speed of tumor shrinkage had a positive relationship with the dose of CTX used; but the survival rate of the tumor-bearing mice had a negative relationship with the dose of CTX used in 2 months after CTX treatment. 15 mg/kg CTX could cure most of the tumor bearing mice, while it had no remarkably inhibitive effects on peripheral blood cells. The perpherial platelet count increased to (1483.4+/-184.4)x10(9)/L in mice 6 h after CTX treatment. There was significant difference compared with that in mice of control group (1086.6+/-81.0)x10(9)/L (P0.05). CTX 15 mg/kg could cure most of bladder tumor-bearing T739 mice. The transient increase of the peripheral platelet count in 6 h after CTX treatment may relate to the antitumor effects of CTX.

DETECTION OF WATER AND/OR HYDROXYL ON ASTEROID (16) Psyche

International Nuclear Information System (INIS)

Takir, Driss; Reddy, Vishnu; Sanchez, Juan A.; Shepard, Michael K.; Emery, Joshua P.

2017-01-01

In order to search for evidence of hydration on M-type asteroid (16) Psyche, we observed this object in the 3 μ m spectral region using the long-wavelength cross-dispersed (LXD: 1.9–4.2 μ m) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility. Our observations show that Psyche exhibits a 3 μ m absorption feature, attributed to water or hydroxyl. The 3 μ m absorption feature is consistent with the hydration features found on the surfaces of water-rich asteroids, attributed to OH- and/or H 2 O-bearing phases (phyllosilicates). The detection of a 3 μ m hydration absorption band on Psyche suggests that this asteroid may not be a metallic core, or it could be a metallic core that has been impacted by carbonaceous material over the past 4.5 Gyr. Our results also indicate rotational spectral variations, which we suggest reflect heterogeneity in the metal/silicate ratio on the surface of Psyche.

DETECTION OF WATER AND/OR HYDROXYL ON ASTEROID (16) Psyche

Energy Technology Data Exchange (ETDEWEB)

Takir, Driss [U.S. Geological Survey, Astrogeology Science Center, Flagstaff, AZ 86001 (United States); Reddy, Vishnu [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Sanchez, Juan A. [Planetary Science Institute, 1700 E Fort Lowell Road, Suite 106, Tucson, AZ 85719 (United States); Shepard, Michael K. [Department of Geography and Geosciences, Bloomsburg University of Pennsylvania, 400 E. Second Street, Bloomsburg, PA 17815 (United States); Emery, Joshua P., E-mail: dtakir@usgs.gov [Earth and Planetary Science Department, Planetary Geosciences Institute, University of Tennessee, Knoxville, TN 37996 (United States)

2017-01-01

In order to search for evidence of hydration on M-type asteroid (16) Psyche, we observed this object in the 3 μ m spectral region using the long-wavelength cross-dispersed (LXD: 1.9–4.2 μ m) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility. Our observations show that Psyche exhibits a 3 μ m absorption feature, attributed to water or hydroxyl. The 3 μ m absorption feature is consistent with the hydration features found on the surfaces of water-rich asteroids, attributed to OH- and/or H{sub 2}O-bearing phases (phyllosilicates). The detection of a 3 μ m hydration absorption band on Psyche suggests that this asteroid may not be a metallic core, or it could be a metallic core that has been impacted by carbonaceous material over the past 4.5 Gyr. Our results also indicate rotational spectral variations, which we suggest reflect heterogeneity in the metal/silicate ratio on the surface of Psyche.

Detection of Water and/or Hydroxyl on Asteroid (16) Psyche

Science.gov (United States)

Takir, Driss; Reddy, Vishnu; Sanchez, Juan A.; Shepard, Michael K.; Emery, Joshua P.

2017-01-01

In order to search for evidence of hydration on M-type asteroid (16) Psyche, we observed this object in the 3 μm spectral region using the long-wavelength cross-dispersed (LXD: 1.9-4.2 μm) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility. Our observations show that Psyche exhibits a 3 μm absorption feature, attributed to water or hydroxyl. The 3 μm absorption feature is consistent with the hydration features found on the surfaces of water-rich asteroids, attributed to OH- and/or H2O-bearing phases (phyllosilicates). The detection of a 3 μm hydration absorption band on Psyche suggests that this asteroid may not be a metallic core, or it could be a metallic core that has been impacted by carbonaceous material over the past 4.5 Gyr. Our results also indicate rotational spectral variations, which we suggest reflect heterogeneity in the metal/silicate ratio on the surface of Psyche.

Water-bearing, high-pressure Ca-silicates

Science.gov (United States)

Németh, Péter; Leinenweber, Kurt; Ohfuji, Hiroaki; Groy, Thomas; Domanik, Kenneth J.; Kovács, István J.; Kovács, Judit S.; Buseck, Peter R.

2017-07-01

Water-bearing minerals provide fundamental knowledge regarding the water budget of the mantle and are geophysically significant through their influence on the rheological and seismic properties of Earth's interior. Here we investigate the CaO-SiO2-H2O system at 17 GPa and 1773 K, corresponding to mantle transition-zone condition, report new high-pressure (HP) water-bearing Ca-silicates and reveal the structural complexity of these phases. We document the HP polymorph of hartrurite (Ca3SiO5), post-hartrurite, which is tetragonal with space group P4/ncc, a = 6.820 (5), c = 10.243 (8) Å, V = 476.4 (8) Å3, and Z = 4, and is isostructural with Sr3SiO5. Post-hartrurite occurs in hydrous and anhydrous forms and coexists with larnite (Ca2SiO4), which we find also has a hydrous counterpart. Si is 4-coordinated in both post-hartrurite and larnite. In their hydrous forms, H substitutes for Si (4H for each Si; hydrogrossular substitution). Fourier transform infrared (FTIR) spectroscopy shows broad hydroxyl absorption bands at ∼3550 cm-1 and at 3500-3550 cm-1 for hydrous post-hartrurite and hydrous larnite, respectively. Hydrous post-hartrurite has a defect composition of Ca2.663Si0.826O5H1.370 (5.84 weight % H2O) according to electron-probe microanalysis (EPMA), and the Si deficiency relative to Ca is also observed in the single-crystal data. Hydrous larnite has average composition of Ca1.924Si0.851O4H0.748 (4.06 weight % H2O) according to EPMA, and it is in agreement with the Si occupancy obtained using X-ray data collected on a single crystal. Superlattice reflections occur in electron-diffraction patterns of the hydrous larnite and could indicate crystallographic ordering of the hydroxyl groups and their associated cation defects. Although textural and EPMA-based compositional evidence suggests that hydrous perovskite may occur in high-Ca-containing (or low silica-activity) systems, the FTIR measurement does not show a well-defined hydroxyl absorption band for this

Experimental contribution to the study of gas bearings

International Nuclear Information System (INIS)

Gobert, G.

1962-01-01

Developments for gas-lubricated bearings are discussed. The study of how the fluid film behaves compared to what one can expect is discussed. Various devices are described which have allowed us to go up to peripheral velocity greater than 400 m/s, leading to rotational speed of several thousand revolutions per second. This is obtained by using an automatic setting for the distance between fixed and rotating walls. (author) [fr

Intracrystalline fractionation of oxygen isotopes between hydroxyl and non-hydroxyl sites in kaolinite measured by thermal dehydroxylation and partial fluorination

Science.gov (United States)

Girard, Jean-Pierre; Savin, Samuel M.

1996-02-01

Thermal dehydroxylation and partial fluorination techniques were used to measure intracrystalline fractionation of oxygen isotopes between hydroxyl and non-hydroxyl sites in kaolinite. Several aliquots of a well characterized, fine-grained (rates, and target temperatures. Measured δ18O values of both the liberated water and the dehydroxylated residue are consistent over a wide range of temperatures (550 850°C) when dehydroxylation is performed in a single-step fashion at a rapid heating rate (>50°C/min.). Similar dehydroxylation experiments indicate that brucite dehydroxylation occurs without any significant isotopic fractionation of the oxygen isotopes. By extrapolation we postulate that no significant fractionation occurs during single-step thermal dehydroxylation of fine-grained kaolinite, provided that dehydroxylation is performed under well controlled conditions. In contrast, gibbsite dehydroxylation is accompanied by substantial isotopic fractionation. This is probably the result of the complex, multi-pathway dehydroxylation reaction of this mineral. Similarly, thermal dehydroxylation of coarsegrained (>1 μm) kaolinites and dickites of weathering and hydrothermal origin yield results that are dependent on the temperature of dehydroxylation. We suggest that this effect may be caused by isotopic exchange during diffusion of water molecules through coarse particles. Partial fluorination of fine-grained kaolinite in the presence of excess F2 at low temperatures (rate of reaction of hydroxyl oxygen than of non-hydroxyl oxygen, but examination of the isotopic data as well as XRD and IR analyses of the residues after partial fluorination indicates that the separation between the two types of oxygen is not complete. The results, therefore, do not yield a reliable δ18O value of the hydroxyl oxygen. The results of this study suggest that the thermal dehydroxylation technique may be appropriate for analysis of OH groups in fine-grained kaolinite. The partial

Synthesis, photophysical and photochemical properties of zinc phthalocyanines bearing fluoro-functionalized substituents

International Nuclear Information System (INIS)

Aktaş, Ayşe; Pişkin, Mehmet; Durmuş, Mahmut; Bıyıklıoğlu, Zekeriya

2014-01-01

In this study, the synthesis of phthalonitrile derivatives bearing fluoro-functionalized groups and their peripherally-tetra substituted zinc phthalocyanine complexes were reported. The phthalonitrile derivatives 2a–5a were prepared by nucleophilic substitution of 4-nitrophthalonitrile with 2-[3-(trifluoromethyl)phenoxy]ethanol, 2-{2-[3-(trifluoromethyl) phenoxy]ethoxy}ethanol, 2-(2,3,5,6-tetrafluorophenoxy)ethanol, 2-[2-(2,3,5,6-tetrafluorophenoxy)ethoxy]ethanol, respectively. Zinc phthalocyanines bearing fluoro-functionalized groups (2b–5b) were obtained from the corresponding phthalonitrile derivatives. The newly synthesized phthalocyanines displayed good solubility in organic solvents such as chloroform (CHCl 3 ), dichloromethane (DCM), tetrahydrofuran (THF), toluene, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). On the other hand, the singlet oxygen, photodegradation, fluorescence quantum yields and fluorescence lifetime of these complexes were determined in DMSO. The effects of the substitution with fluoro-functionalized groups on these parameters were also compared. -- Highlights: • Synthesis of peripherally substituted zinc phthalocyanines. • Photophysical and photochemical properties in DMSO for phthalocyanines. • Photodynamic therapy studies

Synthesis, photophysical and photochemical properties of zinc phthalocyanines bearing fluoro-functionalized substituents

Energy Technology Data Exchange (ETDEWEB)

Aktaş, Ayşe [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Pişkin, Mehmet [Marmara University, Faculty of Art and Science, Department of Chemistry, 34722 Kadikoy-Istanbul (Turkey); Durmuş, Mahmut [Gebze Institute of Technology, Department of Chemistry, PO Box 141, Gebze 41400, Kocaeli (Turkey); Bıyıklıoğlu, Zekeriya, E-mail: zekeriya_61@yahoo.com [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)

2014-01-15

In this study, the synthesis of phthalonitrile derivatives bearing fluoro-functionalized groups and their peripherally-tetra substituted zinc phthalocyanine complexes were reported. The phthalonitrile derivatives 2a–5a were prepared by nucleophilic substitution of 4-nitrophthalonitrile with 2-[3-(trifluoromethyl)phenoxy]ethanol, 2-{2-[3-(trifluoromethyl) phenoxy]ethoxy}ethanol, 2-(2,3,5,6-tetrafluorophenoxy)ethanol, 2-[2-(2,3,5,6-tetrafluorophenoxy)ethoxy]ethanol, respectively. Zinc phthalocyanines bearing fluoro-functionalized groups (2b–5b) were obtained from the corresponding phthalonitrile derivatives. The newly synthesized phthalocyanines displayed good solubility in organic solvents such as chloroform (CHCl{sub 3}), dichloromethane (DCM), tetrahydrofuran (THF), toluene, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). On the other hand, the singlet oxygen, photodegradation, fluorescence quantum yields and fluorescence lifetime of these complexes were determined in DMSO. The effects of the substitution with fluoro-functionalized groups on these parameters were also compared. -- Highlights: • Synthesis of peripherally substituted zinc phthalocyanines. • Photophysical and photochemical properties in DMSO for phthalocyanines. • Photodynamic therapy studies.

Self-hydroxylation of the splicing factor lysyl hydroxylase, JMJD6

DEFF Research Database (Denmark)

Mantri, M.; Webby, C.J.; Loik, N.D.

2012-01-01

The lysyl 5S-hydroxylase, JMJD6 acts on proteins involved in RNA splicing. We find that in the absence of substrate JMJD6 catalyses turnover of 2OG to succinate. H-NMR analyses demonstrate that consumption of 2OG is coupled to succinate formation. MS analyses reveal that JMJD6 undergoes self......-hydroxylation in the presence of Fe(ii) and 2OG resulting in production of 5S-hydroxylysine residues. JMJD6 in human cells is also found to be hydroxylated. Self-hydroxylation of JMJD6 may play a regulatory role in modulating the hydroxylation status of proteins involved in RNA splicing. This journal is...

Peripherally Metalated Porphyrins with Applications in Catalysis, Molecular Electronics and Biomedicine.

Science.gov (United States)

Longevial, Jean-François; Clément, Sébastien; Wytko, Jennifer A; Ruppert, Romain; Weiss, Jean; Richeter, Sébastien

2018-04-24

Porphyrins are conjugated, stable chromophores with a central core that binds a variety of metal ions and an easily functionalized peripheral framework. By combining the catalytic, electronic or cytotoxic properties of selected transition metal complexes with the binding and electronic properties of porphyrins, enhanced characteristics of the ensemble are generated. This review article focuses on porphyrins bearing one or more peripheral transition metal complexes and discusses their potential applications in catalysis or biomedicine. Modulation of the electronic properties and intramolecular communication through coordination bond linkages in bis-porphyrin scaffolds is also presented. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Regioselective alkane hydroxylation with a mutant AlkB enzyme

Science.gov (United States)

Koch, Daniel J.; Arnold, Frances H.

2012-11-13

AlkB from Pseudomonas putida was engineered using in-vivo directed evolution to hydroxylate small chain alkanes. Mutant AlkB-BMO1 hydroxylates propane and butane at the terminal carbon at a rate greater than the wild-type to form 1-propanol and 1-butanol, respectively. Mutant AlkB-BMO2 similarly hydroxylates propane and butane at the terminal carbon at a rate greater than the wild-type to form 1-propanol and 1-butanol, respectively. These biocatalysts are highly active for small chain alkane substrates and their regioselectivity is retained in whole-cell biotransformations.

Hydroxylation of the herbicide isoproturon by fungi isolated from agricultural soil.

Science.gov (United States)

Rønhede, Stig; Jensen, Bo; Rosendahl, Søren; Kragelund, Birthe B; Juhler, René K; Aamand, Jens

2005-12-01

Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N',N'-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea and N-(4-(1-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea. Bacterial metabolism of isoproturon has previously been shown to proceed by an initial demethylation to N-(4-isopropylphenyl)-N'-methylurea. In soils, however, hydroxylated metabolites have also been detected. In this study we identified fungi as organisms that potentially play a major role in the formation of these hydroxylated metabolites in soils treated with isoproturon. Isolates of Mortierella sp. strain Gr4, Phoma cf. eupyrena Gr61, and Alternaria sp. strain Gr174 hydroxylated isoproturon at the first position of the isopropyl side chain, yielding N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea, while Mucor sp. strain Gr22 hydroxylated the molecule at the second position, yielding N-(4-(1-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea. Hydroxylation was the dominant mode of isoproturon transformation in these fungi, although some cultures also produced traces of the N-demethylated metabolite N-(4-isopropylphenyl)-N'-methylurea. A basidiomycete isolate produced a mixture of the two hydroxylated and N-demethylated metabolites at low concentrations. Clonostachys sp. strain Gr141 and putative Tetracladium sp. strain Gr57 did not hydroxylate isoproturon but N demethylated the compound to a minor extent. Mortierella sp. strain Gr4 also produced N-(4-(2-hydroxy-1-methylethyl)phenyl)-N'-methylurea, which is the product resulting from combined N demethylation and hydroxylation.

Hydroxylated PBDEs induce developmental arrest in zebrafish

Energy Technology Data Exchange (ETDEWEB)

Usenko, Crystal Y., E-mail: Crystal_usenko@baylor.edu; Hopkins, David C.; Trumble, Stephen J., E-mail: Stephen_trumble@baylor.edu; Bruce, Erica D., E-mail: Erica_bruce@baylor.edu

2012-07-01

The ubiquitous spread of polybrominated diphenyl ethers (PBDEs) has led to concerns regarding the metabolites of these congeners, in particular hydroxylated PBDEs. There are limited studies regarding the biological interactions of these chemicals, yet there is some concern they may be more toxic than their parent compounds. In this study three hydroxylated PBDEs were assessed for toxicity in embryonic zebrafish: 3-OH-BDE 47, 5-OH-BDE 47, and 6-OH-BDE 47. All three congeners induced developmental arrest in a concentration-dependent manner; however, 6-OH-BDE 47 induced adverse effects at lower concentrations than the other congeners. Furthermore, all three induced cell death; however apoptosis was not observed. In short-term exposures (24–28 hours post fertilization), all hydroxylated PBDEs generated oxidative stress in the region corresponding to the cell death at 5 and 10 ppm. To further investigate the short-term effects that may be responsible for the developmental arrest observed in this study, gene regulation was assessed for embryos exposed to 0.625 ppm 6-OH-BDE 47 from 24 to 28 hpf. Genes involved in stress response, thyroid hormone regulation, and neurodevelopment were significantly upregulated compared to controls; however, genes related to oxidative stress were either unaffected or downregulated. This study suggests that hydroxylated PBDEs disrupt development, and may induce oxidative stress and potentially disrupt the cholinergic system and thyroid hormone homeostasis. -- Highlights: ► OH-PBDEs induce developmental arrest in a concentration-dependent manner. ► Hydroxyl group location influences biological interaction. ► OH-PBDEs induce oxidative stress. ► Thyroid hormone gene regulation was disrupted following exposure. ► To our knowledge, this is the first whole organism study of OH-PBDE toxicity.

Hydroxyl radical induced degradation of ibuprofen

Energy Technology Data Exchange (ETDEWEB)

Illés, Erzsébet, E-mail: erzsebet.illes@chem.u-szeged.hu [Institute of Chemistry, Research Group of Environmental Chemistry, University of Szeged, Szeged (Hungary); Institute of Isotopes, Centre for Energy Research, Hungarian Academy of Sciences, Budapest (Hungary); Takács, Erzsébet [Institute of Isotopes, Centre for Energy Research, Hungarian Academy of Sciences, Budapest (Hungary); Dombi, András [Institute of Chemistry, Research Group of Environmental Chemistry, University of Szeged, Szeged (Hungary); Gajda-Schrantz, Krisztina [Institute of Chemistry, Research Group of Environmental Chemistry, University of Szeged, Szeged (Hungary); Department of Inorganic and Analytical Chemistry, University of Szeged, Szeged (Hungary); EMPA, Laboratory for High Performance Ceramics, Duebendorf (Switzerland); Rácz, Gergely; Gonter, Katalin; Wojnárovits, László [Institute of Isotopes, Centre for Energy Research, Hungarian Academy of Sciences, Budapest (Hungary)

2013-03-01

Pulse radiolysis experiments were used to characterize the intermediates formed from ibuprofen during electron beam irradiation in a solution of 0.1 mmol dm{sup −3}. For end product characterization {sup 60}Co γ-irradiation was used and the samples were evaluated either by taking their UV–vis spectra or by HPLC with UV or MS detection. The reactions of {sup ·}OH resulted in hydroxycyclohexadienyl type radical intermediates. The intermediates produced in further reactions hydroxylated the derivatives of ibuprofen as final products. The hydrated electron attacked the carboxyl group. Ibuprofen degradation is more efficient under oxidative conditions than under reductive conditions. The ecotoxicity of the solution was monitored by Daphnia magna standard microbiotest and Vibrio fischeri luminescent bacteria test. The toxic effect of the aerated ibuprofen solution first increased upon irradiation indicating a higher toxicity of the first degradation products, then decreased with increasing absorbed dose. Highlights: ► In hydroxyl radical attack on the ring mainly hydroxylated products form ► The hydrated electron attacks the carboxyl group. ► Oxidative conditions are more effective in ibuprofen decomposition than reductive. ► Ecotoxicity of ibuprofen solution first increases then decreases with irradiation.

Hydroxyl radical induced degradation of ibuprofen

International Nuclear Information System (INIS)

Illés, Erzsébet; Takács, Erzsébet; Dombi, András; Gajda-Schrantz, Krisztina; Rácz, Gergely; Gonter, Katalin; Wojnárovits, László

2013-01-01

Pulse radiolysis experiments were used to characterize the intermediates formed from ibuprofen during electron beam irradiation in a solution of 0.1 mmol dm −3 . For end product characterization 60 Co γ-irradiation was used and the samples were evaluated either by taking their UV–vis spectra or by HPLC with UV or MS detection. The reactions of · OH resulted in hydroxycyclohexadienyl type radical intermediates. The intermediates produced in further reactions hydroxylated the derivatives of ibuprofen as final products. The hydrated electron attacked the carboxyl group. Ibuprofen degradation is more efficient under oxidative conditions than under reductive conditions. The ecotoxicity of the solution was monitored by Daphnia magna standard microbiotest and Vibrio fischeri luminescent bacteria test. The toxic effect of the aerated ibuprofen solution first increased upon irradiation indicating a higher toxicity of the first degradation products, then decreased with increasing absorbed dose. Highlights: ► In hydroxyl radical attack on the ring mainly hydroxylated products form ► The hydrated electron attacks the carboxyl group. ► Oxidative conditions are more effective in ibuprofen decomposition than reductive. ► Ecotoxicity of ibuprofen solution first increases then decreases with irradiation

Infrared absorption characteristics of hydroxyl groups in coal tars

Energy Technology Data Exchange (ETDEWEB)

Cannon, S A; Chu, C J; Hange, R H; Margrave, J L

1987-01-01

Tar evolution was observed over a temperature range of 150-600 C for four coals. Pittsburgh bituminous, Illinois No.6, Rawhide subbituminous, and Texas lignite. Isolation of the evolved tars in a nitrogen matrix at 15 degrees K produced better resolved infrared spectra than those in a coal matrix, thus enhancing structural characterization of the tar molecules. Two distinct hydroxyl functional groups in the tar molecules free of hydrogen bonding were identified for the first time without interference from H/sub 2/O absorptions. These absorptions at 3626.5 cm/sup -1/ have been assigned to phenolic hydroxyls. It is suggested that carboxylic and aliphatic hydroxyl groups do not survive the vaporization process. Tars from Illinois No.6 were found to contain the largest amount of phenolic hydroxyl; Pittsburgh No. 8 tar contains approximately half of that for Illinois No.6 while Rawhide and Texas lignite contain much less phenolic than either of the other coals. 10 references, 6 figures, 1 table.

Comparison of fluorescence-based techniques for the quantification of particle-induced hydroxyl radicals

Directory of Open Access Journals (Sweden)

Cohn Corey A

2008-02-01

Full Text Available Abstract Background Reactive oxygen species including hydroxyl radicals can cause oxidative stress and mutations. Inhaled particulate matter can trigger formation of hydroxyl radicals, which have been implicated as one of the causes of particulate-induced lung disease. The extreme reactivity of hydroxyl radicals presents challenges to their detection and quantification. Here, three fluorescein derivatives [aminophenyl fluorescamine (APF, amplex ultrared, and dichlorofluorescein (DCFH] and two radical species, proxyl fluorescamine and tempo-9-ac have been compared for their usefulness to measure hydroxyl radicals generated in two different systems: a solution containing ferrous iron and a suspension of pyrite particles. Results APF, amplex ultrared, and DCFH react similarly to the presence of hydroxyl radicals. Proxyl fluorescamine and tempo-9-ac do not react with hydroxyl radicals directly, which reduces their sensitivity. Since both DCFH and amplex ultrared will react with reactive oxygen species other than hydroxyl radicals and another highly reactive species, peroxynitite, they lack specificity. Conclusion The most useful probe evaluated here for hydroxyl radicals formed from cell-free particle suspensions is APF due to its sensitivity and selectivity.

The stability of the hydroxylated (0001) surface of alpha-Al2O3

DEFF Research Database (Denmark)

Lodziana, Zbigniew; Nørskov, Jens Kehlet; Stoltze, Per

2003-01-01

Self-consistent density functional calculations of the hydroxylated (0001) corundum surfaces are presented. It is demonstrated that the hydroxylated surfaces are the most stable under most, but not all, conditions. Hydroxylation significantly lowers the surface free energy of alpha-alumina. The s......Self-consistent density functional calculations of the hydroxylated (0001) corundum surfaces are presented. It is demonstrated that the hydroxylated surfaces are the most stable under most, but not all, conditions. Hydroxylation significantly lowers the surface free energy of alpha......-alumina. The stability of the hydrated surface resolves the discrepancies between the morphology of the alpha-alumina (0001) surface observed under ultra-high vacuum, and at ambient conditions. A method for the calculation of the equilibrium surface stoichiometry is proposed. The proposed approach provides a valuable...

Tuning the Slide-Roll Motion Mode of Carbon Nanotubes via Hydroxyl Groups

Science.gov (United States)

Li, Rui; Wang, Shiwei; Peng, Qing

2018-05-01

Controlling the motion of carbon nanotubes is critical in manipulating nanodevices, including nanorobots. Herein, we investigate the motion behavior of SWCNT (10,10) on Si substrate utilizing molecular dynamics simulations. We show that hydroxyl groups have sensitive effect on the carbon nanotube's motion mode. When the hydroxyl groups' ratio on carbon nanotube and silicon substrate surfaces is larger than 10 and 20%, respectively, the motion of carbon nanotube transforms from sliding to rolling. When the hydroxyl groups' ratio is smaller, the slide or roll mode can be controlled by the speed of carbon nanotube, which is ultimately determined by the competition between the interface potential energy and kinetic energy. The change of motion mode holds true for different carbon nanotubes with hydroxyl groups. The chirality has little effect on the motion behavior, as opposed to the diameter, attributed to the hydroxyl groups' ratio. Our study suggests a new route to control the motion behavior of carbon nanotube via hydroxyl groups.

Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

Energy Technology Data Exchange (ETDEWEB)

Saksono, Nelson; Febiyanti, Irine Ayu, E-mail: irine.ayu41@ui.ac.id; Utami, Nissa; Ibrahim [Department of Chemical Engineering, Universitas Indonesia, Depok 16424, Indonesia Phone: +62217863516, Fax: +62217863515 (Indonesia)

2015-12-29

Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H{sub 2}O{sub 2} amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode.

Effect of curcumin against oxidation of biomolecules by hydroxyl radicals.

Science.gov (United States)

Borra, Sai Krishna; Mahendra, Jaideep; Gurumurthy, Prema; Jayamathi; Iqbal, Shabeer S; Mahendra, Little

2014-10-01

Among various reactive oxygen species, hydroxyl radicals have the strongest chemical activity, which can damage a wide range of essential biomolecules such as lipids, proteins, and DNA. The objective of this study was to investigate the beneficial effects of curcumin on prevention of oxidative damage of biomolecules by hydroxyl radicals generated in in vitro by a Fenton like reaction. We have incubated the serum, plasma and whole blood with H2O2/Cu2+/ Ascorbic acid system for 4 hours at 37 0C and observed the oxidation of biomolecules like albumin, lipids, proteins and DNA. Curcumin at the concentrations of 50,100 and 200 μmoles, prevented the formation of ischemia modified albumin, MDA, protein carbonyls, oxidized DNA and increased the total antioxidant levels and GSH significantly. These observations suggest the hydroxyl radical scavenging potentials of curcumin and protective actions to prevent the oxidation of biomolecules by hydroxyl radicals.

Changes in blood glucose and insulin responses to intravenous glucose tolerance tests and blood biochemical values in adult female Japanese black bears (Ursus thibetanus japonicus).

Science.gov (United States)

Kamine, Akari; Shimozuru, Michito; Shibata, Haruki; Tsubota, Toshio

2012-02-01

The metabolic mechanisms to circannual changes in body mass of bears have yet to be elucidated. We hypothesized that the Japanese black bear (Ursus thibetanus japonicus) has a metabolic mechanism that efficiently converts carbohydrates into body fat by altering insulin sensitivity during the hyperphagic stage before hibernation. To test this hypothesis, we investigated the changes in blood biochemical values and glucose and insulin responses to intravenous glucose tolerance tests (IVGTT) during the active season (August, early and late November). Four, adult, female bears (5-17 years old) were anesthetized with 6 mg/kg TZ (tiletamine HCl and zolazepam HCl) in combination with 0.1 mg/kg acepromazine maleate. The bears were injected intravenously with glucose (0.5 g/kg of body mass), and blood samples were obtained before, at, and intermittently after glucose injection. The basal triglycerides concentration decreased significantly with increase in body mass from August to November. Basal levels of plasma glucose and serum insulin concentrations were not significantly different among groups. The results of IVGTT demonstrated the increased peripheral insulin sensitivity and glucose tolerance in early November. In contrast, peripheral insulin resistance was indicated by the exaggerated insulin response in late November. Our findings suggest that bears shift their glucose and lipid metabolism from the stage of normal activity to the hyperphagic stage in which they show lipogenic-predominant metabolism and accelerate glucose uptake by increasing the peripheral insulin sensitivity.

System for bearing a nuclear reactor vessel cooled by liquid metal

International Nuclear Information System (INIS)

Mahe, A.; Jullien, G.

1976-01-01

The invention relates to a bearing system for supporting a nuclear reactor vessel of the kind which is suspended from the reactor closure slab. The bearing system comprises a ring connected at one end to a collar and at the other end to two collars. The collar connected to the bottom end of the ring forms the top part of the vessel to be supported while the other two collars fit into the slab at two separate places. The ring and collars are disposed in an annular space formed in the slab and dividing it into two parts, i.e., a central part and a peripheral part surrounding the central part of the slab

Characterization of the Ornithine Hydroxylation Step in Albachelin Biosynthesis

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Kendra Bufkin

2017-10-01

Full Text Available N-Hydroxylating monooxygenases (NMOs are involved in siderophore biosynthesis. Siderophores are high affinity iron chelators composed of catechol and hydroxamate functional groups that are synthesized and secreted by microorganisms and plants. Recently, a new siderophore named albachelin was isolated from a culture of Amycolatopsis alba growing under iron-limiting conditions. This work focuses on the expression, purification, and characterization of the NMO, abachelin monooxygenase (AMO from A. alba. This enzyme was purified and characterized in its holo (FAD-bound and apo (FAD-free forms. The apo-AMO could be reconstituted by addition of free FAD. The two forms of AMO hydroxylate ornithine, while lysine increases oxidase activity but is not hydroxylated and display low affinity for NADPH.

Hydroxyl radical reactivity at the air-ice interface

Directory of Open Access Journals (Sweden)

T. F. Kahan

2010-01-01

Full Text Available Hydroxyl radicals are important oxidants in the atmosphere and in natural waters. They are also expected to be important in snow and ice, but their reactivity has not been widely studied in frozen aqueous solution. We have developed a spectroscopic probe to monitor the formation and reactions of hydroxyl radicals in situ. Hydroxyl radicals are produced in aqueous solution via the photolysis of nitrite, nitrate, and hydrogen peroxide, and react rapidly with benzene to form phenol. Similar phenol formation rates were observed in aqueous solution and bulk ice. However, no reaction was observed at air-ice interfaces, or when bulk ice samples were crushed prior to photolysis to increase their surface area. We also monitored the heterogeneous reaction between benzene present at air-water and air-ice interfaces with gas-phase OH produced from HONO photolysis. Rapid phenol formation was observed on water surfaces, but no reaction was observed at the surface of ice. Under the same conditions, we observed rapid loss of the polycyclic aromatic hydrocarbon (PAH anthracene at air-water interfaces, but no loss was observed at air-ice interfaces. Our results suggest that the reactivity of hydroxyl radicals toward aromatic organics is similar in bulk ice samples and in aqueous solution, but is significantly suppressed in the quasi-liquid layer (QLL that exists at air-ice interfaces.

Hydroxyl-dependent Evolution of Oxygen Vacancies Enables the Regeneration of BiOCl photocatalyst

KAUST Repository

Wu, Sujuan

2017-05-02

Photoinduced oxygen vacancies (OVs) are widely investigated as a vital point defect in wide-band-gap semiconductors. Still, the formation mechanism of OVs remains unclear in various materials. To elucidate the formation mechanism of photoinduced OVs in bismuth oxychloride (BiOCl), we synthesized two surface hydroxyl discrete samples in light of the discovery of the significant variance of hydroxyl groups before and after UV light exposure. It is noted that OVs can be obtained easily after UV light irradiation in the sample with surface hydroxyl groups, while variable changes were observed in samples without surface hydroxyls. Density functional theory (DFT) calculations reveal that the binding energy of Bi-O is drastically influenced by surficial hydroxyl groups, which is intensely correlated to the formation of photoinduced OVs. Moreover, DFT calculations reveal that the adsorbed water molecules are energetically favored to dissociate into separate hydroxyl groups at the OV sites via proton transfer to a neighboring bridging oxygen atom, forming two bridging hydroxyl groups per initial oxygen vacancy. This result is consistent with the experimental observation that the disappearance of photoinduced OVs and the recovery of hydroxyl groups on the surface of BiOCl after exposed to a H2O(g)-rich atmosphere, and finally enables the regeneration of BiOCl photocatalyst. Here, we introduce new insights that the evolution of photoinduced OVs is dependent on surface hydroxyl groups, which will lead to the regeneration of active sites in semiconductors. This work is useful for controllable designs of defective semiconductors for applications in photocatalysis and photovoltaics.

The effect of adenosine A(2A) receptor antagonists on hydroxyl radical, dopamine, and glutamate in the striatum of rats with altered function of VMAT2.

Science.gov (United States)

Gołembiowska, Krystyna; Dziubina, Anna

2012-08-01

It has been shown that a decreased vesicular monoamine transporter (VMAT2) function and the disruption of dopamine (DA) storage is an early contributor to oxidative damage of dopamine neurons in Parkinson's disease (PD). In our previous study, we demonstrated that adenosine A(2A) receptor antagonists suppressed oxidative stress in 6-hydroxydopamine-treated rats suggesting that this effect may account for neuroprotective properties of drugs. In the present study, rats were injected with reserpine (10 mg/kg sc) and 18 h later the effect of the adenosine A(2A) receptor antagonists 8-(3-chlorostyryl)caffeine (CSC) and 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM 241385) on extracellular DA, glutamate and hydroxyl radical formation was studied in the rat striatum using in vivo microdialysis. By disrupting VMAT2 function, reserpine depleted DA stores, and increased glutamate and hydroxyl radical levels in the rat striatum. CSC (1 mg/kg) but not ZM 241385 (3 mg/kg) increased extracellular DA level and production of hydroxyl radical in reserpinised rats. Both antagonists decreased the reserpine-induced increase in extracellular glutamate. L-3,4-Dihydroxyphenylalanine (L-DOPA) (25 mg/kg) significantly enhanced extracellular DA, had no effect on reserpine-induced hydroxyl radical production and decreased extracellular glutamate concentration. CSC but not ZM 241385 given jointly with L-DOPA increased the effect of L-DOPA on extracellular DA and augmented the reserpine-induced hydroxyl radical production. CSC and ZM 241385 did not influence extracellular glutamate level, which was decreased by L-DOPA. It seems that by decreasing the MAO-dependent DA metabolism rate, CSC raised cytosolic DA and by DA autoxidation, it induced hydroxyl radical overproduction. Thus, the methylxanthine A(2A) receptor antagonists bearing properties of MAO-B inhibitor, like CSC, may cause a risk of oxidative stress resulting from dysfunctional DA storage

Anaerobic Dehalogenation of Hydroxylated Polychlorinated Biphenyls by Desulfitobacterium dehalogenans

OpenAIRE

Wiegel, Juergen; Zhang, Xiaoming; Wu, Qingzhong

1999-01-01

Ten years after reports on the existence of anaerobic dehalogenation of polychlorinated biphenyls (PCBs) in sediment slurries, we report here on the rapid reductive dehalogenation of para-hydroxylated PCBs (HO-PCBs), the excreted main metabolites of PCB in mammals, which can exhibit estrogenic and antiestrogenic activities in humans. The anaerobic bacterium Desulfitobacterium dehalogenans completely dehalogenates all flanking chlorines (chlorines in ortho position to the para-hydroxyl group) ...

Functionalization of hydroxyl terminated polybutadiene with ...

Indian Academy of Sciences (India)

CBDT), has been covalently attached at the terminal carbon atoms of the hydroxyl terminated polybutadiene (HTPB) backbone. The modification of HTPB backbone by CBDT molecule does not affect the unique physico-chemical properties such ...

Polaprezinc reduces paclitaxel-induced peripheral neuropathy in rats without affecting anti-tumor activity

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Kuniaki Tsutsumi

2016-06-01

Full Text Available Paclitaxel, an anticancer drug, frequently causes painful peripheral neuropathy. In this study, we investigated the preventive effect of polaprezinc on paclitaxel-induced peripheral neuropathy in rats. Polaprezinc (3 mg/kg, p.o., once daily inhibited the development of mechanical allodynia induced by paclitaxel (4 mg/kg, i.p., on days 1, 3, 5 and 7 and suppressed the paclitaxel-induced increase in macrophage migration in dorsal root ganglion cells. In addition, polaprezinc did not affect the anti-tumor activity of paclitaxel in cultured cell lines or tumor-bearing mice. These results suggest a clinical indication for polaprezinc in the prevention of paclitaxel-induced neuropathy.

Raman and FTIR spectroscopic studies on two hydroxylated tung oils (HTO) bearing conjugated double bonds

Science.gov (United States)

Zhuang, Yuwei; Ren, Zhiyong; Jiang, Lei; Zhang, Jiaxiang; Wang, Huafen; Zhang, Guobao

2018-06-01

Tung oil (TO) was used as a model compound to study two hydroxylated tung oils (HTO), prepared from TO by either aminolysis (HTO-am) or alcoholysis (HTO-al). Main bands in Raman and FTIR spectra were initially assigned based on the detailed analysis of the compound spectra before and after exposure to elevated temperature (200 °C). The effect of heat treatment in air on spectral bands, and especially on the changes associated with double bonds, were then investigated. In the present work, changes in spectral bands due to heat treatment were compared with those revealed in the previous work of others. The results show that the conjugated triene structure of TO has been retained during alcoholysis and aminolysis, to yield the HTOs studied; yet the change of the triene structure caused by heating is different among the three samples; the H-bonding strength between OH and Cdbnd O in HTO-am is higher than that in HTO-al; the changes in HTO vOH and vCdbnd O bands in FTIR caused by the present heat treatment were significant; for TO, there is a big difference between changes in spectra as caused by thermal exposure, compared to those caused by ageing under UV light or exposure to a catalyst. The present work has laid additional groundwork for further study of the reactions of such triply conjugated double bond structures under different ageing conditions.

Thermophysical properties of hydroxyl ammonium ionic liquids

International Nuclear Information System (INIS)

Kurnia, K.A.; Wilfred, C.D.; Murugesan, T.

2009-01-01

The thermophysical properties of hydroxyl ammonium ionic liquids: density ρ, T = (293.15 to 363.15) K; dynamic viscosity η, T = (298.2 to 348.2) K; and refractive indices n D , T = (293.15 to 333.15) K have been measured. The coefficients of thermal expansion α, values were calculated from the experimental density results using an empirical correlation for T = (293.15 to 363.15) K. The variation of volume expansion of ionic liquids studied was found to be independent of temperature within the range covered in the present work. The thermal decomposition temperature 'T d ' for all the six hydroxyl ammonium ionic liquids is also investigated using thermogravimetric analyzer (TGA)

Hydroxyl migration disorders the surface structure of hydroxyapatite nanoparticles

Science.gov (United States)

Cheng, Xiajie; Wu, Hong; Zhang, Li; Ma, Xingtao; Zhang, Xingdong; Yang, Mingli

2017-09-01

The surface structure of nano-hydroxyapatite (HAP) was investigated using a combined simulated annealing and molecular dynamics method. The stationary structures of nano-HAP with 4-7 nm in diameter and annealed under different temperatures were analyzed in terms of pair distribution function, structural factor, mean square displacement and atomic coordination number. The particles possess different structures from bulk crystal. A clear radial change in their atomic arrangements was noted. From core to surface the structures change from ordered to disordered. A three-shell model was proposed to describe the structure evolution of nano-HAP. Atoms in the core zone keep their arrangements as in crystal, while atoms in the surface shell are in short-range order and long-range disorder, adopting a typically amorphous structure. Atoms in the middle shell have small displacements and/or deflections but basically retain their original locations as in crystal. The disordered shell is about 1 nm in thickness, in agreement with experimental observations. The disordering mainly stems from hydroxyl migration during which hydroxyls move to the surface and bond with the exposed Ca ions, and their left vacancies bring about a rearrangement of nearby atoms. The disordering is to some extent different for particles unannealed under different temperatures, resulting from fewer number of migrated hydroxyls at lower temperatures. Particles with different sizes have similar surface structures, and their surface energy decreases with increasing size. Moreover, the surface energy is reduced by hydroxyl migration because the exposed Ca ions on the surface are ionically bonded with the migrated hydroxyls. Our calculations proposed a new structure model for nano-HAP, which indicates a surface structure with activities different from those without surface reorganization. This is particularly interesting because most bioactivities of biomaterials are dominated by their surface activity.

Testosterone 15β-hydroxylation by solvent tolerant Pseudomonas putida S12

NARCIS (Netherlands)

Ruijssenaars, H.J.; Sperling, E.M.G.M.; Wiegerinck, P.H.G.; Brands, F.T.L.; Wery, J.; Bont, J.A.M.de

2007-01-01

A steroid 15β-hydroxylating whole-cell solvent tolerant biocatalyst was constructed by expressing the Bacillus megaterium steroid hydroxylase CYP106A2 in the solvent tolerant Pseudomonas putida S12. Testosterone hydroxylation was improved by a factor 16 by co-expressing Fer, a putative Fe-S protein

Isolation and partial characterization of peripheral blood CD4+ T cell clones expressing γδT cell receptors

International Nuclear Information System (INIS)

Kyoizumi, Seishi; Akiyama, Mitoshi; Hirai, Yuko; Kusunoki, Yoichiro.

1990-06-01

Rare T cell clones bearing both CD4 and T cell receptors (TCRγ and TCRδ) were obtained from human peripheral blood by cell sorting using anti-CD4 and anti-TCRδ1 antibodies. All the clones established were reactive with anti-TCRγδ1 antibody, whereas only about 20 % of the clones showed reactivity with anti-δTCS1 antibody. Unlike CD4 + T cells bearing TCRαβ, all the clones tested were lectin-dependent and showed CD3 antibody-redirected cytolytic activity. About 60 % exhibited natural killer cell-like activity. Immunoprecipitation analysis of TCRγδ showed that each clone expressed either a disulfide-linked or nondisulfide-linked heterodimer consisting of 37-44 kilodalton TCRγ and TCRδ chains. Southern blot analyses of TCRγ and TCRδ genes revealed some identical rearrangement patterns, suggesting the limited heterogeneity of CD4 + TCRγδ + T cells in peripheral blood. (author)

Differential effects of collagen prolyl 3-hydroxylation on skeletal tissues.

Directory of Open Access Journals (Sweden)

Erica P Homan

2014-01-01

Full Text Available Mutations in the genes encoding cartilage associated protein (CRTAP and prolyl 3-hydroxylase 1 (P3H1 encoded by LEPRE1 were the first identified causes of recessive Osteogenesis Imperfecta (OI. These proteins, together with cyclophilin B (encoded by PPIB, form a complex that 3-hydroxylates a single proline residue on the α1(I chain (Pro986 and has cis/trans isomerase (PPIase activity essential for proper collagen folding. Recent data suggest that prolyl 3-hydroxylation of Pro986 is not required for the structural stability of collagen; however, the absence of this post-translational modification may disrupt protein-protein interactions integral for proper collagen folding and lead to collagen over-modification. P3H1 and CRTAP stabilize each other and absence of one results in degradation of the other. Hence, hypomorphic or loss of function mutations of either gene cause loss of the whole complex and its associated functions. The relative contribution of losing this complex's 3-hydroxylation versus PPIase and collagen chaperone activities to the phenotype of recessive OI is unknown. To distinguish between these functions, we generated knock-in mice carrying a single amino acid substitution in the catalytic site of P3h1 (Lepre1(H662A . This substitution abolished P3h1 activity but retained ability to form a complex with Crtap and thus the collagen chaperone function. Knock-in mice showed absence of prolyl 3-hydroxylation at Pro986 of the α1(I and α1(II collagen chains but no significant over-modification at other collagen residues. They were normal in appearance, had no growth defects and normal cartilage growth plate histology but showed decreased trabecular bone mass. This new mouse model recapitulates elements of the bone phenotype of OI but not the cartilage and growth phenotypes caused by loss of the prolyl 3-hydroxylation complex. Our observations suggest differential tissue consequences due to selective inactivation of P3H1 hydroxylase

Presence of hydrogen peroxide, a source of hydroxyl radicals, in acid electrolyzed water.

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Takayuki Mokudai

Full Text Available BACKGROUND: Acid electrolyzed water (AEW, which is produced through the electrolysis of dilute sodium chloride (NaCl or potassium chloride solution, is used as a disinfectant in various fields because of its potent antimicrobial activity. The hydroxyl radical, an oxygen radical species, is often suggested as a putative active ingredient for AEW antimicrobial activity. METHODOLOGY/PRINCIPAL FINDINGS: The aim of the present study is to detect hydroxyl radicals in AEW. The hydroxyl radicals in AEW prepared under different conditions were determined using an electron spin resonance (ESR technique. A signal from 5,5-dimethyl-1-pyrroline N-oxide (DMPO-OH, an adduct of DMPO and the hydroxyl radical, was detected in AEW prepared by double or triple electrolyses of 1% NaCl but not of 0.1% NaCl solution. Then the presence of hydrogen peroxide as a proposed source of hydroxyl radicals was examined using a combination of ESR and a Fenton reaction. The DMPO-OH signal was clearly detected, even in AEW prepared by single electrolysis of 0.1% NaCl solution, when ferrous sulfate was added to induce a Fenton reaction, indicating the presence of hydrogen peroxide in the AEW. Since sodium formate, a hydroxyl radical scavenger, did not affect the bactericidal activity of AEW, it is concluded that the radical is unlikely to contribute to the antimicrobial activity of AEW, although a small amount of the radical is produced from hydrogen peroxide. Dimethyl sulfoxide, the other hydroxyl radical scavenger used in the present study, canceled the bactericidal activity of AEW, accompanied by complete depletion of free available chlorine, suggesting that hypochlorous acid is probably a major contributor to the antimicrobial activity. CONCLUSIONS: It is strongly suggested that although hydrogen peroxide is present in AEW as a source of hydroxyl radicals, the antimicrobial activity of AEW does not depend on these radicals.

Bearing system

Science.gov (United States)

Kapich, Davorin D.

1987-01-01

A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

Functionalization of hydroxyl terminated polybutadiene with ...

Indian Academy of Sciences (India)

Administrator

The hydroxyl terminated polybutadiene (HTPB) used in this work was prepared by free radical polymerization using hydrogen peroxide as initiator and was received from HEMRL Pune, India, as a gift sample. The molecu- lar weight and polydispersity of the HTPB was deter- mined by using gel permeable chromatography ...

Measurement of hydroxyl radical production in ultrasonic aqueous solutions by a novel chemiluminescence method.

Science.gov (United States)

Hu, Yufei; Zhang, Zhujun; Yang, Chunyan

2008-07-01

Measurement methods for ultrasonic fields are important for reasons of safety. The investigation of an ultrasonic field can be performed by detecting the yield of hydroxyl radicals resulting from ultrasonic cavitations. In this paper, a novel method is introduced for detecting hydroxyl radicals by a chemiluminescence (CL) reaction of luminol-hydrogen peroxide (H2O2)-K5[Cu(HIO6)2](DPC). The yield of hydroxyl radicals is calculated directly by the relative CL intensity according to the corresponding concentration of H2O2. This proposed CL method makes it possible to perform an in-line and real-time assay of hydroxyl radicals in an ultrasonic aqueous solution. With flow injection (FI) technology, this novel CL reaction is sensitive enough to detect ultra trace amounts of H2O2 with a limit of detection (3sigma) of 4.1 x 10(-11) mol L(-1). The influences of ultrasonic output power and ultrasonic treatment time on the yield of hydroxyl radicals by an ultrasound generator were also studied. The results indicate that the amount of hydroxyl radicals increases with the increase of ultrasonic output power (< or = 15 W mL(-1)). There is a linear relationship between the time of ultrasonic treatment and the yield of H2O2. The ultrasonic field of an ultrasonic cleaning baths has been measured by calculating the yield of hydroxyl radicals.

Mechanism of aromatic hydroxylation of lidocaine at a Pt electrode under acidic conditions

International Nuclear Information System (INIS)

Gul, Turan; Bischoff, Rainer; Permentier, Hjalmar P.

2017-01-01

Aromatic hydroxylation reactions, which are mainly catalyzed by cytochrome P450 (CYP) enzymes in vivo, are some of the most important reactions of Phase I metabolism, because insertion of a hydroxyl group into a lipophilic drug compound increases its hydrophilicity and prepares it for subsequent Phase II metabolic conjugation reactions as a prerequisite to excretion. Aromatic hydroxylation metabolites of pharmaceuticals may be obtained through various synthetic and enzymatic methods Electrochemical oxidation is an alternative with advantages in terms of mild reaction conditions and less hazardous chemicals. In the present study, we report that aromatic hydroxylation metabolites of lidocaine can be readily obtained electrochemically under aqueous acidic conditions at platinum electrodes. Our results show that the dominant N-dealkylation reaction can be suppressed by decreasing the solution pH below 0.5 resulting in selective 3-hydroxylidocaine, which is an in vivo metabolite of lidocaine. Experiments in 18 O labelled water indicated that water is the primary source of oxygen, while dissolved molecular oxygen contributes to a minor extent to the hydroxylation reaction.

Peripheral neuropathy

Science.gov (United States)

... peripheral; Neuritis - peripheral; Nerve disease; Polyneuropathy; Chronic pain - peripheral neuropathy ... Philadelphia, PA: Elsevier; 2016:chap 107. Shy ME. Peripheral neuropathies. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

The hydroxyl species and acid sites on diatomite surface: a combined IR and Raman study

Science.gov (United States)

Yuan, P.; Wu, D. Q.; He, H. P.; Lin, Z. Y.

2004-04-01

Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Raman spectroscopy of adsorbed pyridine molecules (Py-Raman) and in situ Py-IR have been used to investigate the hydroxyl species and acid sites on diatomite surfaces. The Lewis (L) and Brønsted (B) acid sites, and various hydroxyl species, including isolated hydroxyl groups, H-bonded hydroxyl groups and physically adsorbed water, are identified. The L acid sites in diatomite samples are resulted from the clay impurities, and the B acid sites are resulted from some moderate strength H-bonded hydroxyl groups. At room temperature, both of the isolated and H-bonded silanols associate with the physically adsorbed water by hydrogen bond. After calcination treatment, physically adsorbed water will be desorbed from the silanols, and the silanols will condense with the increase of temperature. Generally, the H-bonded silanols condense more easily than the isolated ones. The properties of surface hydroxyl species of diatomaceous silica are more similar to precipitated silica rather than fumed silica.

Modeling gadolinium-bearing fuel in Ringhals PWRs using CASMO/SIMULATE

International Nuclear Information System (INIS)

Kurcyusz, E.

1993-01-01

Ringhals units 2, 3, and 4 are Westinghouse three-loop, 157-assembly pressurized water reactors (PWRs) operated by Vattenfall. Originally, all three reactors were loaded in an out-in scheme using reload fuel without burnable poisons. In recent cycles, gadolinium-bearing fuel was introduced to enable a low-leakage loading pattern and minimize fuel cycle costs. This paper focuses on the Fragema 17 x 17 AFA design with peripheral gadolinium rods loaded in units 3 and 4. The Ringhals units are modeled using the Studsvik core management system, consisting of the CASMO-3 transport theory lattice physics code,and the SIMULATE-3 advanced nodal reactor analysis code. The results of the studies verifying the accuracy of CASMO-3/SIMULATE-3 on the assemblies with peripheral gadolinium rods are presented in this paper. The verification was carried out against CASMO-3 color-set calculations and measured reactor data

Journal bearing

Science.gov (United States)

Menke, John R.; Boeker, Gilbert F.

1976-05-11

1. An improved journal bearing comprising in combination a non-rotatable cylindrical bearing member having a first bearing surface, a rotatable cylindrical bearing member having a confronting second bearing surface having a plurality of bearing elements, a source of lubricant adjacent said bearing elements for supplying lubricant thereto, each bearing element consisting of a pair of elongated relatively shallowly depressed surfaces lying in a cylindrical surface co-axial with the non-depressed surface and diverging from one another in the direction of rotation and obliquely arranged with respect to the axis of rotation of said rotatable member to cause a flow of lubricant longitudinally along said depressed surfaces from their distal ends toward their proximal ends as said bearing members are rotated relative to one another, each depressed surface subtending a radial angle of less than 360.degree., and means for rotating said rotatable bearing member to cause the lubricant to flow across and along said depressed surfaces, the flow of lubricant being impeded by the non-depressed portions of said second bearing surface to cause an increase in the lubricant pressure.

Structure and Dynamics of Hydroxyl-Functionalized Protic Ammonium Carboxylate Ionic Liquids.

Science.gov (United States)

Thummuru, Dhileep Nagi Reddy; Mallik, Bhabani S

2017-10-26

We performed classical molecular dynamics simulations to investigate the structure and dynamics of protic ionic liquids, 2-hydroxy ethylammonium acetate, ethylammonium hydroxyacetate, and 2-hydroxyethylammonium hydroxyacetate at ambient conditions. Structural properties such as density, radial distribution functions, spatial distribution functions, and structure factors have been calculated. Dynamic properties such as mean square displacements, as well as residence and hydrogen bond dynamics have also been calculated. Hydrogen bond lifetimes and residence times change with the addition of hydroxyl groups. We observe that when a hydroxyl group is present on the cation, dynamics become very slow and it forms a strong hydrogen bond with carboxylate oxygen atoms of the anion. The hydroxyl functionalized ILs show more dynamic diversity than structurally similar ILs.

Atmospheric hydroxyl radical production from electronically excited NO2 and H2O.

Science.gov (United States)

Li, Shuping; Matthews, Jamie; Sinha, Amitabha

2008-03-21

Hydroxyl radicals are often called the "detergent" of the atmosphere because they control the atmosphere's capacity to cleanse itself of pollutants. Here, we show that the reaction of electronically excited nitrogen dioxide with water can be an important source of tropospheric hydroxyl radicals. Using measured rate data, along with available solar flux and atmospheric mixing ratios, we demonstrate that the tropospheric hydroxyl contribution from this source can be a substantial fraction (50%) of that from the traditional O(1D) + H2O reaction in the boundary-layer region for high solar zenith angles. Inclusion of this chemistry is expected to affect modeling of urban air quality, where the interactions of sunlight with emitted NOx species, volatile organic compounds, and hydroxyl radicals are central in determining the rate of ozone formation.

Camshaft bearing arrangement

Energy Technology Data Exchange (ETDEWEB)

Aoi, K.; Ozawa, T.

1986-06-10

A bearing arrangement is described for the camshaft of an internal combustion engine or the like which camshaft is formed along its length in axial order with a first bearing surface, a first cam lobe, a second bearing surface, a second cam lobe, a third bearing surface, a third cam lobe and a fourth bearing surface, the improvement comprising first bearing means extending around substantially the full circumference of the first bearing surface and journaling the first bearing surface, second bearing means extending around substantially less than the circumference of the second bearing surface and journaling the second bearing surface, third bearing means extending around substantially less than the circumference of the third bearing surface and journaling the third bearing surface, and fourth bearing means extending around substantially the full circumference of the fourth bearing surface and journaling the first bearing surface.

Anti-hepatoma activity and mechanism of corn silk polysaccharides in H22 tumor-bearing mice.

Science.gov (United States)

Yang, Jingyue; Li, Xiao; Xue, Yan; Wang, Nan; Liu, Wenchao

2014-03-01

Corn silk is a well known traditional Chinese herbal medicine and corn silk polysaccharides (CSP) possess multiple pharmacological activities. However, the antitumor effect of CSP on hepatocarcinoma has not been studied. This study aimed to investigate the effects of CSP on tumor growth and immune functions in H22 hepatocarcinoma tumor-bearing mice. The results demonstrated that CSP could not only inhibit the tumor growth, but also extended the survival time of H22 tumor-bearing mice. Besides, CSP administration could increase the body weight, peripheral white blood cells (WBC) count, thymus index and spleen index of H22 tumor-bearing mice. Furthermore, the production of serum cytokines in H22 tumor-bearing mice, such as IL-2, IL-6 and TNF-α, was enhanced by CSP treatment. In addition, no toxicological effects were observed on hepatic function and renal function in CSP-treated mice transplanted H22 tumor cells. In summary, this experimental finding indicated that CSP could elevate the immune functions in H22 tumor-bearing mice to enhance its antitumor activity and CSP seems to be a safe and effective agent for the treatment of hepatocellular carcinoma. Copyright © 2013 Elsevier B.V. All rights reserved.

Hydroxyl-dependent Evolution of Oxygen Vacancies Enables the Regeneration of BiOCl photocatalyst

KAUST Repository

Wu, Sujuan; Xiong, Jiawei; Sun, Jianguo; Hood, Zachary D.; Zeng, Wen; Yang, Zhenzhong; Gu, Lin; Zhang, Xixiang; Yang, Shize

2017-01-01

irradiation in the sample with surface hydroxyl groups, while variable changes were observed in samples without surface hydroxyls. Density functional theory (DFT) calculations reveal that the binding energy of Bi-O is drastically influenced by surficial

SU-F-T-676: Measurement of Hydroxyl Radicals in Radiolized Water Systems

Energy Technology Data Exchange (ETDEWEB)

Ouyang, Z; Ngwa, W [University of Massachusetts Lowell, Lowell, MA (United States); Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (United States); Strack, G; Sajo, E [University of Massachusetts Lowell, Lowell, MA (United States)

2016-06-15

Purpose: Hydroxyl radicals can be produced within tissue by radiation therapy, and they are largely responsible for DNA damage and cell killing. Coumarin-3-carboxylic acid (3-CCA) and crystal violet are reported to react with hydroxyl radicals and can be used for fluorescence and absorbance measurements, respectively. This study assesses the ability of hydroxyl measurement for both 3-CCA and crystal violet in radiolized water systems in order to provide dosimetric information in radiation chemistry and radiation biology experiments. Methods: 3-CCA and crystal violet were both dissolved in phosphate buffered saline (PBS, pH 7.4) with final concentrations 0.5 mg/mL and 0.05 mg/mL. 3-CCA and control solutions (PBS only) were loaded in black bottom 96-well plates. Crystal violet and control solutions were loaded in clear bottom 96-well plates. The prepared solutions were irradiated at 2 Gy using a small animal radiation research platform. Fluorescence reading with 360 nm excitation wavelength and 485 nm emission wavelength was done for 3-CCA, and absorbance reading at wavelength 580 nm was done for crystal violet before and after radiation. Results: 3-CCA showed clear difference in fluorescence before and after radiation, which suggested hydroxyl production during radiation. However, crystal violet absorbance at 580 nm was not changed significantly by radiation. Conclusion: The overall conclusion is that 3-CCA can be used for hydroxyl measurement in radiolized water systems, while crystal violet cannot, although crystal violet is reported widely to react with hydroxyl radicals produced in Fenton reactions. Possible reasons could relate to reaction pH.

Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α upregulation in human tumours.

Directory of Open Access Journals (Sweden)

Cameron E Snell

Full Text Available The stabilisation of HIF-α is central to the transcriptional response of animals to hypoxia, regulating the expression of hundreds of genes including those involved in angiogenesis, metabolism and metastasis. HIF-α is degraded under normoxic conditions by proline hydroxylation, which allows for recognition and ubiquitination by the von-Hippel-Lindau (VHL E3 ligase complex. The aim of our study was to investigate the posttranslational modification of HIF-1α in tumours, to assess whether there are additional mechanisms besides reduced hydroxylation leading to stability. To this end we optimised antibodies against the proline-hydroxylated forms of HIF-1α for use in formalin fixed paraffin embedded (FFPE immunohistochemistry to assess effects in tumour cells in vivo. We found that HIF-1α proline-hydroxylated at both VHL binding sites (Pro402 and Pro564, was present in hypoxic regions of a wide range of tumours, tumour xenografts and in moderately hypoxic cells in vitro. Staining for hydroxylated HIF-1α can identify a subset of breast cancer patients with poorer prognosis and may be a better marker than total HIF-1α levels. The expression of unhydroxylated HIF-1α positively correlates with VHL in breast cancer suggesting that VHL may be rate-limiting for HIF degradation. Our conclusions are that the degradation of proline-hydroxylated HIF-1α may be rate-limited in tumours and therefore provides new insights into mechanisms of HIF upregulation. Persistence of proline-hydroxylated HIF-1α in perinecrotic areas suggests there is adequate oxygen to support prolyl hydroxylase domain (PHD activity and proline-hydroxylated HIF-1α may be the predominant form associated with the poorer prognosis that higher levels of HIF-1α confer.

CATALYTIC PERFORMANCES OF Fe2O3/TS-1 CATALYST IN PHENOL HYDROXYLATION REACTION

Directory of Open Access Journals (Sweden)

Didik Prasetyoko

2010-07-01

Full Text Available Hydroxylation reaction of phenol into diphenol, such as hydroquinone and catechol, has a great role in many industrial applications. Phenol hydroxylation reaction can be carried out using Titanium Silicalite-1 (TS-1 as catalyst and H2O2 as an oxidant. TS-1 catalyst shows high activity and selectivity for phenol hydroxylation reaction. However, its hydrophobic sites lead to slow H2O2 adsorption toward the active site of TS-1. Consequently, the reaction rate of phenol hydroxylation reaction is tends to be low. Addition of metal oxide Fe2O3 enhanced hydrophilicity of TS-1 catalyst. Liquid phase catalytic phenol hydroxylation using hydrogen peroxide as oxidant was carried out over iron (III oxide-modified TS-1 catalyst (Fe2O3/TS-1, that were prepared by impregnation method using iron (III nitrate as precursor and characterized by X-ray diffraction, infrared spectroscopy, nitrogen adsorption, pyridine adsorption, and hydrophilicity techniques. Catalysts 1Fe2O3/TS-1 showed maximum catalytic activity of hydroquinone product. In this research, the increase of hydroquinone formation rate is due to the higher hydrophilicity of Fe2O3/TS-1 catalysts compare to the parent catalyst, TS-1.   Keywords: Fe2O3/TS-1, hydrophilic site, phenol hydroxylation

Synthesis and pH-dependent assembly of isotropic and anisotropic gold nanoparticles functionalized with hydroxyl-bearing amino acids

Science.gov (United States)

Swami, Anuradha; Mittal, Sherry; Chopra, Adity; Sharma, Rohit K.; Wangoo, Nishima

2018-03-01

In recent years, the synthesis of gold nanostructures of controllable shapes and dimensions has become a subject of intensive and interesting studies. Especially, anisotropic gold nanostructures such as nanoplates, nanoribbons, nanoprisms and nanorods have attracted much attention due to their striking optical properties and promising applications in electronics, photonics, sensing and biomedicine. Keeping this in mind, in the present report, an unprecedented, facile and one pot synthesis of isotropic (spherical) and anisotropic (triangular, pentagonal, hexagonal, rod shaped) gold nanomaterials via pH controlled shape modulation using hydroxyl moeity containing α-amino acids (Serine, Threonine, Tyrosine) as both reducing and capping agents is reported. The synthesized nanostructures have been further characterized by UV-Vis spectroscopy and transmission electron microscopy. It was deduced from these studies that pH played a key role in the anisotropic growth of gold nanostructures. These gold nanoparticles can be further used for applications in biosensing, plasmonics, and electrocatalysis and others involving surface enhanced raman scattering. This study is therefore, important from the point of view of using amino acids for the synthesis of gold nanoparticles of different shapes and sizes leading towards the development of inventive biosensors and biocompatible nanoconstructs.

Prolyl hydroxylation regulates protein degradation, synthesis, and splicing in human induced pluripotent stem cell-derived cardiomyocytes.

Science.gov (United States)

Stoehr, Andrea; Yang, Yanqin; Patel, Sajni; Evangelista, Alicia M; Aponte, Angel; Wang, Guanghui; Liu, Poching; Boylston, Jennifer; Kloner, Philip H; Lin, Yongshun; Gucek, Marjan; Zhu, Jun; Murphy, Elizabeth

2016-06-01

Protein hydroxylases are oxygen- and α-ketoglutarate-dependent enzymes that catalyse hydroxylation of amino acids such as proline, thus linking oxygen and metabolism to enzymatic activity. Prolyl hydroxylation is a dynamic post-translational modification that regulates protein stability and protein-protein interactions; however, the extent of this modification is largely uncharacterized. The goals of this study are to investigate the biological consequences of prolyl hydroxylation and to identify new targets that undergo prolyl hydroxylation in human cardiomyocytes. We used human induced pluripotent stem cell-derived cardiomyocytes in combination with pulse-chase amino acid labelling and proteomics to analyse the effects of prolyl hydroxylation on protein degradation and synthesis. We identified 167 proteins that exhibit differences in degradation with inhibition of prolyl hydroxylation by dimethyloxalylglycine (DMOG); 164 were stabilized. Proteins involved in RNA splicing such as serine/arginine-rich splicing factor 2 (SRSF2) and splicing factor and proline- and glutamine-rich (SFPQ) were stabilized with DMOG. DMOG also decreased protein translation of cytoskeletal and sarcomeric proteins such as α-cardiac actin. We searched the mass spectrometry data for proline hydroxylation and identified 134 high confidence peptides mapping to 78 unique proteins. We identified SRSF2, SFPQ, α-cardiac actin, and cardiac titin as prolyl hydroxylated. We identified 29 prolyl hydroxylated proteins that showed a significant difference in either protein degradation or synthesis. Additionally, we performed next-generation RNA sequencing and showed that the observed decrease in protein synthesis was not due to changes in mRNA levels. Because RNA splicing factors were prolyl hydroxylated, we investigated splicing ± inhibition of prolyl hydroxylation and detected 369 alternative splicing events, with a preponderance of exon skipping. This study provides the first extensive

Hydroxyl radical induced degradation of salicylates in aerated aqueous solution

International Nuclear Information System (INIS)

Szabó, László; Tóth, Tünde; Homlok, Renáta; Rácz, Gergely; Takács, Erzsébet; Wojnárovits, László

2014-01-01

Ionizing radiation induced degradation of acetylsalicylic acid, its hydrolysis product salicylic acid and a salicylic acid derivative 5-sulpho-salicylic acid, was investigated in dilute aqueous solutions by UV–vis spectrophotometry, HPLC separation and diode-array or MS/MS detection, chemical oxygen demand, total organic carbon content and by Vibrio fischeri toxicity measurements. Hydroxyl radicals were shown to degrade these molecules readily, and first degradation products were hydroxylated derivatives in all cases. Due to the by-products, among them hydrogen peroxide, the toxicity first increased and then decreased with the absorbed dose. With prolonged irradiation complete mineralization was achieved. - Highlights: • In OH induced reactions of salicylates first products are hydroxylated derivatives. • With prolonged irradiation dihydroxy derivatives also form. • In aerated solutions the one-electron oxidant OH induces 3–4 oxidations. • Toxicity first increases and then decreases with dose mainly due to H 2 O 2 formation. • The toxicity in tap water is smaller than in pure water

The risk of pedestrian collisions with peripheral visual field loss.

Science.gov (United States)

Peli, Eli; Apfelbaum, Henry; Berson, Eliot L; Goldstein, Robert B

2016-12-01

Patients with peripheral field loss complain of colliding with other pedestrians in open-space environments such as shopping malls. Field expansion devices (e.g., prisms) can create artificial peripheral islands of vision. We investigated the visual angle at which these islands can be most effective for avoiding pedestrian collisions, by modeling the collision risk density as a function of bearing angle of pedestrians relative to the patient. Pedestrians at all possible locations were assumed to be moving in all directions with equal probability within a reasonable range of walking speeds. The risk density was found to be highly anisotropic. It peaked at ≈45° eccentricity. Increasing pedestrian speed range shifted the risk to higher eccentricities. The risk density is independent of time to collision. The model results were compared to the binocular residual peripheral island locations of 42 patients with forms of retinitis pigmentosa. The natural residual island prevalence also peaked nasally at about 45° but temporally at about 75°. This asymmetry resulted in a complementary coverage of the binocular field of view. Natural residual binocular island eccentricities seem well matched to the collision-risk density function, optimizing detection of other walking pedestrians (nasally) and of faster hazards (temporally). Field expansion prism devices will be most effective if they can create artificial peripheral islands at about 45° eccentricities. The collision risk and residual island findings raise interesting questions about normal visual development.

Rate constant for reaction of hydroxyl radicals with bicarbonate ions

International Nuclear Information System (INIS)

Buxton, G.V.; Elliot, A.J.

1986-01-01

The rate constant for reaction of hydroxyl radicals with the bicarbonate ion has been determined to be 8.5 x 10 6 dm 3 mol -1 s -1 . This value was calculated from: the measured rate of formation of the CO 3 - radical in pulsed electron irradiation of bicarbonate solutions over the pH range 7.0 to 9.4; the pK for the equilibrium HCO 3 - = CO 3 2- + H + ; and the rate constant for hydroxyl radicals reacting with the carbonate ion. (author)

11 µ-Hydroxylation of cortexolone using immobilized ...

African Journals Online (AJOL)

Transformation of cortexolone to cortisol and prednisolone by the filamentous fungus Cunninghamella elegans protoplasts as a research tool was studied. The immobilized protoplasts of the fungus hydroxylated cortexolone at 11β -position had significantly higher activity than the free protoplasts. Sucrose as an osmotic ...

Regioselective hydroxylation of isoflavones by Streptomyces avermitilis MA-4680.

Science.gov (United States)

Roh, Changhyun; Seo, Su-Hyun; Choi, Kwon-Young; Cha, Minho; Pandey, Bishnu Prasad; Kim, June-Hyung; Park, Jun-Seong; Kim, Duck Hee; Chang, Ih Seop; Kim, Byung-Gee

2009-07-01

Screening of bacterial whole cells was performed for regioselective hydroxylation of daidzein and genistein. Among the strains examined, Streptomyces avermitilis MA-4680 showed high ortho-dihydroxylation activity to produce 3',4',7-trihydroxyisoflavone and 3',4',5,7-tetrahydroxyisoflavone from daidzein (4',7-dihydroxyisoflavone) and genistein (4',5,7-trihydroxyisoflavone), respectively. Using 100 mg cells (wet wt.) and 1% (v/v) Triton X100 in 1 ml of total reaction volume, where 100 microl of the substrate solution (0.5 mM in 10% (v/v) mixed solvent of DMSO:MeOH = 3:7) was added to 900 microl of potassium phosphate buffer (100 mM, pH 7.2), a 16% molar conversion yield of 3',4',7-trihydroxyisoflavone was obtained from 0.5 mM daidzein after 24 h of reaction time at 28 degrees C and 200 rpm. Ketoconazole significantly (ca. 90%) inhibited the ortho-hydroxylation activity of daidzein, suggesting that cytochrome P450 enzymes putatively play roles in regiospecific daidzein hydroxylation. The analysis of the reaction products was determined by gas chromatography/mass spectrometry (GC/MS) and (1)H NMR.

Monkey liver cytochrome P450 2C19 is involved in R- and S-warfarin 7-hydroxylation.

Science.gov (United States)

Hosoi, Yoshio; Uno, Yasuhiro; Murayama, Norie; Fujino, Hideki; Shukuya, Mitsunori; Iwasaki, Kazuhide; Shimizu, Makiko; Utoh, Masahiro; Yamazaki, Hiroshi

2012-12-15

Cynomolgus monkeys are widely used as primate models in preclinical studies. However, some differences are occasionally seen between monkeys and humans in the activities of cytochrome P450 enzymes. R- and S-warfarin are model substrates for stereoselective oxidation in humans. In this current research, the activities of monkey liver microsomes and 14 recombinantly expressed monkey cytochrome P450 enzymes were analyzed with respect to R- and S-warfarin 6- and 7-hydroxylation. Monkey liver microsomes efficiently mediated both R- and S-warfarin 7-hydroxylation, in contrast to human liver microsomes, which preferentially catalyzed S-warfarin 7-hydroxylation. R-Warfarin 7-hydroxylation activities in monkey liver microsomes were not inhibited by α-naphthoflavone or ketoconazole, and were roughly correlated with P450 2C19 levels and flurbiprofen 4-hydroxylation activities in microsomes from 20 monkey livers. In contrast, S-warfarin 7-hydroxylation activities were not correlated with the four marker drug oxidation activities used. Among the 14 recombinantly expressed monkey P450 enzymes tested, P450 2C19 had the highest activities for R- and S-warfarin 7-hydroxylations. Monkey P450 3A4 and 3A5 slowly mediated R- and S-warfarin 6-hydroxylations. Kinetic analysis revealed that monkey P450 2C19 had high V(max) and low K(m) values for R-warfarin 7-hydroxylation, comparable to those for monkey liver microsomes. Monkey P450 2C19 also mediated S-warfarin 7-hydroxylation with V(max) and V(max)/K(m) values comparable to those for recombinant human P450 2C9. R-warfarin could dock favorably into monkey P450 2C19 modeled. These results collectively suggest high activities for monkey liver P450 2C19 toward R- and S-warfarin 6- and 7-hydroxylation in contrast to the saturation kinetics of human P450 2C9-mediated S-warfarin 7-hydroxylation. Copyright © 2012 Elsevier Inc. All rights reserved.

Synthesis of hydroxyl liquid polybutadiene by photochemical decomposition of hydrogen peroxide

International Nuclear Information System (INIS)

Moutinho, Marcus Tadeu Moura

1995-01-01

The synthesis of hydroxyl terminated polybutadienes (HTPB) by photochemical decomposition (λ=254 nm) of hydrogen peroxide (H 2 O 2 ) in alcoholic medium was studied. The influence of reaction time, H 2 O 2 and alcohol concentrations, type of alcohol and radiation intensity on the polymerization rate was determined. Higher polymerization rates were attained when t-butyl alcohol was used as the compatibilizing agent (19% conversion after 8 hours). The HTPBs were characterized by hydroxyl content (acetylation), functionality, IR microstructure and types of hydroxyl groups ( 1 H-NMR and 13 C-NMR), 2-vinyl cyclohexene (VCH) content and viscosity. The polymers showed molecular weights (Mn) in the range of 458 to 1,099, molecular weight distribution (Mw/Mn) in the range of 1.20 to 1.46 and functionality between 1.2 and 3.2 depending on the alcohol used. NMR results 1 H and 13 C) revealed low cis content for the polybutadienes and identified primary and secondary hydroxyl groups, depending on the alcohol employed as compatibilizing agent. The incorporation of alcohol in polymer chain ends was evidenced. The produced HTPBs presented viscosities in the range of 850 to 1,250 cP (at 25 deg C) and were VCH free. (author)

Mechanism of aromatic hydroxylation of lidocaine at a Pt electrode under acidic conditions

NARCIS (Netherlands)

Gul, Turan; Bischoff, Rainer; Permentier, Hjalmar P.

2017-01-01

Aromatic hydroxylation reactions, which are mainly catalyzed by cytochrome P450 (CYP) enzymes in vivo, are some of the most important reactions of Phase I metabolism, because insertion of a hydroxyl group into a lipophilic drug compound increases its hydrophilicity and prepares it for subsequent

Study of hydroxylation of benzene and toluene using a micro-DBD plasma reactor

International Nuclear Information System (INIS)

Sekiguchi, H; Ando, M; Kojima, H

2005-01-01

The hydroxylation behaviour of benzene and toluene were studied using a micro-plasma reactor, where an atmospheric non-thermal plasma was generated by a dielectric barrier discharge (DBD). The results indicated that oxidation products primarily consisted of phenol and C 4 -compounds for benzene hydroxylation, whereas cresol, benzaldehyde, benzylalcohol and C 4 -compounds were detected for toluene hydroxylation. By taking into consideration the reaction mechanism in the plasma reactor, these products were classified into (1) oxidation of the aromatic ring and functional group on the ring and (2) cleavage of the aromatic ring or dissociation of the functional group on the ring

Hydroxylation of the Herbicide Isoproturon by Fungi Isolated from Agricultural Soil

OpenAIRE

Rønhede, Stig; Jensen, Bo; Rosendahl, Søren; Kragelund, Birthe B.; Juhler, René K.; Aamand, Jens

2005-01-01

Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N′,N′-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N′,N′-dimethylurea and N-(4-(1-hydroxy-1-methylethyl)phenyl)-N′,N′-dimethylurea. Bacterial metabolism of isoproturon has previously been shown to proceed by an initial demethylation to N-(4-isopropylphenyl)-N′-methylurea. In soils, however, hydroxylated metaboli...

Hydroxyl-radical induced dechlorination of pentachlorophenol in water

International Nuclear Information System (INIS)

He Yongke; Wu Jilan; Fang Xingwang; Sonntag, C. von

1998-01-01

The hydroxyl-radical induced dechlorination of pentachlorophenol (PCP) in water has been investigated pulse radiolytically. Hydroxyl radicals react with PCP by both electron transfer and addition. The former process results in pentachlorophenoxyl radicals (PCP-O), the latter process followed by rapid HCl elimination gives birth to deprotonated hydroxytetrachlorophenoxyl radicals ( - O-TCP-O). These phenoxyl radicals exhibit maximum absorption around 452 nm, which hinders the proper estimation of the ratio of the two processes. However, these two processes cause different changes in conductivity. In basic solution, the electron transfer causes a conductivity increase due to the formation of OH - whereas an addition followed by HCl elimination results in a conductivity decrease. The concurrence of these two processes reduces the relative variation in conductivity, from which about 53% electron transfer is deduced

Grizzly bear

Science.gov (United States)

Schwartz, C.C.; Miller, S.D.; Haroldson, M.A.; Feldhamer, G.; Thompson, B.; Chapman, J.

2003-01-01

The grizzly bear inspires fear, awe, and respect in humans to a degree unmatched by any other North American wild mammal. Like other bear species, it can inflict serious injury and death on humans and sometimes does. Unlike the polar bear (Ursus maritimus) of the sparsely inhabited northern arctic, however, grizzly bears still live in areas visited by crowds of people, where presence of the grizzly remains physically real and emotionally dominant. A hike in the wilderness that includes grizzly bears is different from a stroll in a forest from which grizzly bears have been purged; nighttime conversations around the campfire and dreams in the tent reflect the presence of the great bear. Contributing to the aura of the grizzly bear is the mixture of myth and reality about its ferocity. unpredictable disposition, large size, strength, huge canines, long claws, keen senses, swiftness, and playfulness. They share characteristics with humans such as generalist life history strategies. extended periods of maternal care, and omnivorous diets. These factors capture the human imagination in ways distinct from other North American mammals. Precontact Native American legends reflected the same fascination with the grizzly bear as modern stories and legends (Rockwell 1991).

On the spatial coincidence of hydroxyl and methanol masers

Science.gov (United States)

Hartquist, T. W.; Menten, K. M.; Lepp, S.; Dalgarno, A.

1995-01-01

We argue that purely gas-phase chemical models for the production of OH in hydroxyl masers around ultracompact H II regions such as W3(OH) cannot account for the CH_3OH in the methanol masers that are found to coincide with the hydroxyl masers in these sources. We suggest that the CH_3OH in the masers is injected into the gas phase by evaporation of the grain mantles, the grains being heated by the passage of weak shocks. Gas evaporation also injects H_2O into the gas. Photodissociation of H_2O, CH_3OH and OH occur at similar rates, and substantial abundances of CH_3OH and OH coexist.

EPR detection of hydroxyl radical generation and its interaction with antioxidant system in Carassius auratus exposed to pentachlorophenol

Energy Technology Data Exchange (ETDEWEB)

Luo Yi [Key Laboratory of Pollution Processes and Environmental Criteria (Nankai University), Ministry of Education, College of Environmental Sciences and Engineering, Nankai University, Tianjin 300071 (China); Wang Xiaorong, E-mail: yiyluo@gmail.com [State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210093 (China); Ji Liangliang; Su Yan [State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210093 (China)

2009-11-15

In the present study, direct evidence of hydroxyl radical production in livers of Carassius auratus exposed to pentachlorophenol (PCP) was provided using electron paramagnetic resonance (EPR) with spin-trapping. A dose-effect relationship was obtained between hydroxyl radical intensities and PCP exposure. It was observed that hydroxyl radical was significantly induced by 0.001 mg l{sup -1} (below the criteria for Chinese fishery water quality) of PCP exposure. A strong positive correlation (r = 0.9581, p < 0.001) was observed between PCP liver concentrations and hydroxyl radical intensities within 7 d of PCP exposure, which suggests that hydroxyl radical are mainly produced from PCP itself. However, no correlation was observed between PCP liver concentrations and hydroxyl radical intensities after 7 d, and a higher intensity of hydroxyl radical could still be observed when the PCP liver concentrations decreased to a lower level, which suggests that other mechanisms may possibly contribute to hydroxyl radical production after 7 d. The glutathione/oxidized glutathione (GSH/GSSG) ratio decreased below that of the control level during the entire period of PCP exposure (0.05 mg l{sup -1}), which suggested oxidative stress occurred.

Progress modelling of aqueous electrons and hydroxyl radicals in RAIM code

Energy Technology Data Exchange (ETDEWEB)

Kim, A Yeong; Kim, Han-Chul; Lee, Jongseong [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2015-10-15

In this paper, the RAIM code was revised minutely with regards to aqueous electrons and hydroxyl radicals, and simulated the P10T2 test. The recent study indicated that the RAIM had the potential for improvement of simulating the iodine behavior influenced by water radiolysis products such as aqueous electrons and hydroxyl radicals. In the existing RAIM modelling, it was considered that aqueous electrons only interacted with oxygen as a consumption reaction, but the reaction with hydrogen peroxide also could be major contributor to the iodine behavior as well as the consumption reaction of aqueous electrons. In case of hydroxyl radicals, RAIM took no notice of the pH impact. In other words, it dealt with the consumption reaction constants but not as a variable of pH. In this communication, the procedures to develop the model related to aqueous electrons and hydroxyl radicals in RAIM will be addressed. And the upgraded RAIM (RAIM-1, 2, 3) codes were applied to OECD-BIP P10T2 test which showed the effect of pH on the iodine behavior and compared with the existing RAIM1.8.3 code. Comparing with the existing RAIM, the improvement reduced the difference about 10%. However, the absolute difference values that is about one order at pH 10 could not be reduced by this approach.

77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

Science.gov (United States)

2012-11-26

... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...

Regioselective alkane hydroxylation with a mutant CYP153A6 enzyme

Science.gov (United States)

Koch, Daniel J.; Arnold, Frances H.

2013-01-29

Cytochrome P450 CYP153A6 from Myobacterium sp. strain HXN1500 was engineered using in-vivo directed evolution to hydroxylate small-chain alkanes regioselectively. Mutant CYP153A6-BMO1 selectively hydroxylates butane and pentane at the terminal carbon to form 1-butanol and 1-pentanol, respectively, at rates greater than wild-type CYP153A6 enzymes. This biocatalyst is highly active for small-chain alkane substrates and the regioselectivity is retained in whole-cell biotransformations.

Phylogeography of mitochondrial DNA variation in brown bears and polar bears.

Science.gov (United States)

Shields, G F; Adams, D; Garner, G; Labelle, M; Pietsch, J; Ramsay, M; Schwartz, C; Titus, K; Williamson, S

2000-05-01

We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples. Copyright 2000 Academic Press.

Phylogeography of mitochondrial DNA variation in brown bears and polar bears

Science.gov (United States)

Shields, Gerald F.; Adams, Deborah; Garner, Gerald W.; Labelle, Martine; Pietsch, Jacy; Ramsay, Malcolm; Schwartz, Charles; Titus, Kimberly; Williamson, Scott

2000-01-01

We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.

Introgressive hybridization: brown bears as vectors for polar bear alleles.

Science.gov (United States)

Hailer, Frank

2015-03-01

The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. © 2015 John Wiley & Sons Ltd.

Novel denture-cleaning system based on hydroxyl radical disinfection.

Science.gov (United States)

Kanno, Taro; Nakamura, Keisuke; Ikai, Hiroyo; Hayashi, Eisei; Shirato, Midori; Mokudai, Takayuki; Iwasawa, Atsuo; Niwano, Yoshimi; Kohno, Masahiro; Sasaki, Keiichi

2012-01-01

The purpose of this study was to evaluate a new denture-cleaning device using hydroxyl radicals generated from photolysis of hydrogen peroxide (H2O2). Electron spin resonance analysis demonstrated that the yield of hydroxyl radicals increased with the concentration of H2O2 and light irradiation time. Staphylococcus aureus, Pseudomonas aeruginosa, and methicillin-resistant S aureus were killed within 10 minutes with a > 5-log reduction when treated with photolysis of 500 mM H2O2; Candida albicans was killed within 30 minutes with a > 4-log reduction with photolysis of 1,000 mM H2O2. The clinical test demonstrated that the device could effectively reduce microorganisms in denture plaque by approximately 7-log order within 20 minutes.

Steroid hydroxylations: A paradigm for cytochrome P450 catalyzed mammalian monooxygenation reactions

International Nuclear Information System (INIS)

Estabrook, Ronald W.

2005-01-01

The present article reviews the history of research on the hydroxylation of steroid hormones as catalyzed by enzymes present in mammalian tissues. The report describes how studies of steroid hormone synthesis have played a central role in the discovery of the monooxygenase functions of the cytochrome P450s. Studies of steroid hydroxylation reactions can be credited with showing that: (a) the adrenal mitochondrial enzyme catalyzing the 11β-hydroxylation of deoxycorticosterone was the first mammalian enzyme shown by O 18 studies to be an oxygenase; (b) the adrenal microsomal enzyme catalyzing the 21-hydroxylation of steroids was the first mammalian enzyme to show experimentally the proposed 1:1:1 stoichiometry (substrate:oxygen:reduced pyridine nucleotide) of a monooxygenase reaction; (c) application of the photochemical action spectrum technique for reversal of carbon monoxide inhibition of the 21-hydroxylation of 17α-OH progesterone was the first demonstration that cytochrome P450 was an oxygenase; (d) spectrophotometric studies of the binding of 17α-OH progesterone to bovine adrenal microsomal P450 revealed the first step in the cyclic reaction scheme of P450, as it catalyzes the 'activation' of oxygen in a monooxygenase reaction; (e) purified adrenodoxin was shown to function as an electron transport component of the adrenal mitochondrial monooxygenase system required for the activity of the 11β-hydroxylase reaction. Adrenodoxin was the first iron-sulfur protein isolated and purified from mammalian tissues and the first soluble protein identified as a reductase of a P450; (f) fractionation of adrenal mitochondrial P450 and incubation with adrenodoxin and a cytosolic (flavoprotein) fraction were the first demonstration of the reconstitution of a mammalian P450 monooxygenase reaction

Glutathione--hydroxyl radical interaction: a theoretical study on radical recognition process.

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Béla Fiser

Full Text Available Non-reactive, comparative (2 × 1.2 μs molecular dynamics simulations were carried out to characterize the interactions between glutathione (GSH, host molecule and hydroxyl radical (OH(•, guest molecule. From this analysis, two distinct steps were identified in the recognition process of hydroxyl radical by glutathione: catching and steering, based on the interactions between the host-guest molecules. Over 78% of all interactions are related to the catching mechanism via complex formation between anionic carboxyl groups and the OH radical, hence both terminal residues of GSH serve as recognition sites. The glycine residue has an additional role in the recognition of OH radical, namely the steering. The flexibility of the Gly residue enables the formation of further interactions of other parts of glutathione (e.g. thiol, α- and β-carbons with the lone electron pair of the hydroxyl radical. Moreover, quantum chemical calculations were carried out on selected GSH/OH(• complexes and on appropriate GSH conformers to describe the energy profile of the recognition process. The relative enthalpy and the free energy changes of the radical recognition of the strongest complexes varied from -42.4 to -27.8 kJ/mol and from -21.3 to 9.8 kJ/mol, respectively. These complexes, containing two or more intermolecular interactions, would be the starting configurations for the hydrogen atom migration to quench the hydroxyl radical via different reaction channels.

V color centers in electrolytically colored hydroxyl-doped sodium chloride crystals

International Nuclear Information System (INIS)

Gu Hongen; Song Cuiying; Han Li

2006-01-01

Hydroxyl-doped sodium chloride crystals were successfully colored electrolytically by using pointed anode and flat cathode at various temperatures and under various electric field strengths. V 2 and V 3 color centers were produced in the colored crystals. Current-time curves for the electrolytic colorations were given, and activation energy for the V 2 and V 3 color center migration was determined. Production of the V 2 and V 3 color centers and formation of current zones for the electrolytic colorations of the hydroxyl-doped sodium chloride crystals are explained

Hydroxylation of the Herbicide Isoproturon by Fungi Isolated from Agricultural soil

DEFF Research Database (Denmark)

Rønhede, S.; Jensen, Bo; Rosendahl, Søren

2005-01-01

Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N',N'-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea and N-(4-(1-hydroxy-1-methylethyl)phenyl)-N......Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [N-(4-isopropylphenyl)-N',N'-dimethylurea] to N-(4-(2-hydroxy-1-methylethyl)phenyl)-N',N'-dimethylurea and N-(4-(1-hydroxy-1-methylethyl...

Modeling the thermostability of surface functionalisation by oxygen, hydroxyl, and water on nanodiamonds.

Science.gov (United States)

Lai, Lin; Barnard, Amanda S

2011-06-01

Understanding nanodiamond functionalisation is of great importance for biological and medical applications. Here we examine the stabilities of oxygen, hydroxyl, and water functionalisation of the nanodiamonds using the self-consistent charge density functional tight-binding simulations. We find that the oxygen and hydroxyl termination are thermodynamically favourable and form strong C–O covalent bonds on the nanodiamond surface in an O2 and H2 gas reservoir, which confirms previous experiments. Yet, the thermodynamic stabilities of oxygen and hydroxyl functionalisation decrease dramatically in a water vapour reservoir. In contrast, H2O molecules are found to be physically adsorbed on the nanodiamond surface, and forced chemical adsorption results in decomposition of H2O. Moreover, the functionalisation efficiency is found to be facet dependent. The oxygen functionalisation prefers the {100} facets as opposed to alternative facets in an O2 and H2 gas reservoir. The hydroxyl functionalisation favors the {111} surfaces in an O2 and H2 reservoir and the {100} facets in a water vapour reservoir, respectively. This facet selectivity is found to be largely dependent upon the environmental temperature, chemical reservoir, and morphology of the nanodiamonds.

Electrolytic coloration and spectral properties of hydroxyl-doped potassium chloride single crystals

International Nuclear Information System (INIS)

Gu Hongen; Wu Yanru

2011-01-01

Hydroxyl-doped potassium chloride single crystals are colored electrolytically at various temperatures and voltages using a pointed cathode and a flat anode. Characteristic OH - spectral band is observed in the absorption spectrum of uncolored single crystal. Characteristic O - , OH - , U, V 2 , V 3 , O 2- -V a + , F, R 2 and M spectral bands are observed simultaneously in absorption spectra of colored single crystals. Current-time curve for electrolytic coloration of hydroxyl-doped potassium chloride single crystal and its relationship with electrolytic coloration process are given. Production and conversion of color centers are explained. - Highlights: → Expanded the traditional electrolysis method. → Hydroxyl-doped potassium chloride crystals were colored electrolytically for the first time. → Useful V, F and F-aggregate color centers were produced in colored crystals. → V color centers were produced directly and F and F-aggregate color centers indirectly.

FIH Regulates Cellular Metabolism through Hydroxylation of the Deubiquitinase OTUB1.

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Carsten C Scholz

2016-01-01

Full Text Available The asparagine hydroxylase, factor inhibiting HIF (FIH, confers oxygen-dependence upon the hypoxia-inducible factor (HIF, a master regulator of the cellular adaptive response to hypoxia. Studies investigating whether asparagine hydroxylation is a general regulatory oxygen-dependent modification have identified multiple non-HIF targets for FIH. However, the functional consequences of this outside of the HIF pathway remain unclear. Here, we demonstrate that the deubiquitinase ovarian tumor domain containing ubiquitin aldehyde binding protein 1 (OTUB1 is a substrate for hydroxylation by FIH on N22. Mutation of N22 leads to a profound change in the interaction of OTUB1 with proteins important in cellular metabolism. Furthermore, in cultured cells, overexpression of N22A mutant OTUB1 impairs cellular metabolic processes when compared to wild type. Based on these data, we hypothesize that OTUB1 is a target for functional hydroxylation by FIH. Additionally, we propose that our results provide new insight into the regulation of cellular energy metabolism during hypoxic stress and the potential for targeting hydroxylases for therapeutic benefit.

- Hydroxylated Anthraquinones Produced by Geosmithia species

Czech Academy of Sciences Publication Activity Database

Stodůlková, Eva; Kolařík, Miroslav; Křesinová, Zdena; Kuzma, Marek; Šulc, Miroslav; Man, Petr; Novák, Petr; Maršík, Petr; Landa, Přemysl; Olšovská, Jana; Chudíčková, Milada; Pažoutová, Sylvie; Černý, J.; Bella, J.; Flieger, Miroslav

2009-01-01

Roč. 54, č. 3 (2009), s. 179-187 ISSN 0015-5632 R&D Projects: GA AV ČR KAN200200651; GA MŠk LC07017; GA MŠk 1M0506; GA ČR GP203/05/P575 Grant - others:CZ(CZ) 205/2004 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z50380511 Keywords : hydroxylated anthraquinones * staphylococcus aureus * mammalian cell lines Subject RIV: EE - Microbiology, Virology Impact factor: 0.978, year: 2009

EcoBears

DEFF Research Database (Denmark)

Nielsen, Nick; Pedersen, Sandra Bleuenn; Sørensen, Jens Ager

2015-01-01

In this paper, we introduce the EcoBears concept that aims to augment household appliances with functional and aesthetic features to promote their "use'' and "longevity of use'' to prevent their disposal. The EcoBears also aim to support the communication of environmental issues in the home setting....... We present our initial design and implementation of the EcoBears that consist of two bear modules (a mother and her cub). We also present our preliminary concept validations and lessons learned to be considered for future directions....

Stable isotopes to detect food-conditioned bears and to evaluate human-bear management

Science.gov (United States)

Hopkins, John B.; Koch, Paul L.; Schwartz, Charles C.; Ferguson, Jake M.; Greenleaf, Schuyler S.; Kalinowski, Steven T.

2012-01-01

We used genetic and stable isotope analysis of hair from free-ranging black bears (Ursus americanus) in Yosemite National Park, California, USA to: 1) identify bears that consume human food, 2) estimate the diets of these bears, and 3) evaluate the Yosemite human–bear management program. Specifically, we analyzed the isotopic composition of hair from bears known a priori to be food-conditioned or non-food-conditioned and used these data to predict whether bears with an unknown management status were food-conditioned (FC) or non-food-conditioned (NFC). We used a stable isotope mixing model to estimate the proportional contribution of natural foods (plants and animals) versus human food in the diets of FC bears. We then used results from both analyses to evaluate proactive (population-level) and reactive (individual-level) human–bear management, and discussed new metrics to evaluate the overall human–bear management program in Yosemite. Our results indicated that 19 out of 145 (13%) unknown bears sampled from 2005 to 2007 were food-conditioned. The proportion of human food in the diets of known FC bears likely declined from 2001–2003 to 2005–2007, suggesting proactive management was successful in reducing the amount of human food available to bears. In contrast, reactive management was not successful in changing the management status of known FC bears to NFC bears, or in reducing the contribution of human food to the diets of FC bears. Nine known FC bears were recaptured on 14 occasions from 2001 to 2007; all bears were classified as FC during subsequent recaptures, and human–bear management did not reduce the amount of human food in the diets of FC bears. Based on our results, we suggest Yosemite continue implementing proactive human–bear management, reevaluate reactive management, and consider removing problem bears (those involved in repeated bear incidents) from the population.

Hydrotreating of compounds and mixtures of compounds having mercapto and hydroxyl groups

Energy Technology Data Exchange (ETDEWEB)

Viljava, T.R.; Krause, A.O.I. [Helsinki University of Technology, Espoo (Finland)

1997-07-01

Simultaneous hydrodesulfurization (HDS) and hydrodeoxygenation (HDO) of mercapto and hydroxyl group containing benzenes was studied using a commercial presulfided CoMo/{gamma}- Al{sub 2}O{sub 3} catalyst under hydrotreating conditions (150-280 deg C, 7 MPa). Mercaptobenzene, phenol and 4-mercaptophenol were used as model compounds, and CS{sub 2} was used as precursor for H{sub 2}S. The HDS rate of a mercapto group in the presence of a hydroxyl substituent in the para position was higher than that for the molecule containing only a mercapto group. When the hydroxyl group was present as phenol, the HDS rate of the mercapto group was about 30% lower than that for mercaptobenzene without an oxygen-containing additive. The decrease in the HDS rate was independent of the initial molar ratio of sulfur and oxygen within the ratios studied (5:1-1:1). The HDO rate of a hydroxyl group was suppressed by the mercapto group present either in the same or in a separate molecule. HDO reactions did not start until HDS conversion was almost complete. CS{sub 2} also decreased the HDO rate of phenol. When compared to the reactions of phenol alone, the rate of the hydrogenolysis route to benzene was decreased in the presence of a sulfur additive more than the hydrogenolysis- hydrogenation route to cyclohexane. 19 refs.

State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics.

Science.gov (United States)

Tse, Peter W; Wang, Dong

2017-02-14

Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL). Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI) so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics

Directory of Open Access Journals (Sweden)

Peter W. Tse

2017-02-01

Full Text Available Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL. Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

Apoptosis of THP-1 derived macrophages induced by sonodynamic therapy using a new sonosensitizer hydroxyl acetylated curcumin.

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Longbin Zheng

Full Text Available Curcumin is extracted from the rhizomes of the traditional Chinese herb Curcuma longa. Our previous study indicated curcumin was able to function as a sonosensitizer. Hydroxyl acylated curcumin was synthesized from curcumin to eliminate the unstable hydroxy perssad in our group. The potential use of Hydroxyl acylated curcumin as a sonosensitizer for sonodynamic therapy (SDT requires further exploration. This study investigated the sonodynamic effect of Hydroxyl acylated curcumin on THP-1 macrophage. THP-1 macrophages were cultured with Hydroxyl acylated curcumin at a concentration of 5.0 μg/mL for 4 hours and then exposed to pulse ultrasound irradiation (0.5 W/cm2 with 1.0 MHz for 5 min, 10 min and 15 min. Six hours later, cell viability decreased significantly by CCK-8 assay. After ultrasound irradiation, the ratio of apoptosis and necrosis in SDT group was higher than that in control, Hydroxyl acylated curcumin alone and ultrasound alone. Moreover, the apoptotic rate was higher than necrotic rate with the flow cytometry analysis. Furthermore, Hydroxyl acylated curcumin-SDT induced reactive oxygen species (ROS generation in THP-1 macrophages immediately after the ultrasound treatment while ROS generation was reduced significantly with the scavenger of singlet oxygen Sodium azide (NaN3. Hydroxyl acylated curcumin-SDT led to a conspicuous loss of mitochondrial membrane potential (MMP compared with other groups, while MMP was increased significantly with the scavenger of singlet oxygen Sodium azide (NaN3, ROS inhibitor N-acetyl cysteine (NAC and Mitochondrial Permeability Transition Pore (MPTP inhibitor Cyclosporin A (CsA. The cytochrome C, cleaved-Caspase-9, cleaved-Caspase-3 and cleaved-PARP upregulated after SDT through Western blotting. These findings suggested that Hydroxyl acylated curcumin under low-intensity ultrasound had sonodynamic effect on THP-1 macrophages via generation of intracellular singlet oxygen and mitochondria

Comparison of Alignment Correction Angles Between Fixed-Bearing and Mobile-Bearing UKA.

Science.gov (United States)

Inoue, Atsuo; Arai, Yuji; Nakagawa, Shuji; Inoue, Hiroaki; Yamazoe, Shoichi; Kubo, Toshikazu

2016-01-01

Good outcomes have been reported with both fixed-bearing and mobile-bearing unicompartmental knee arthroplasty (UKA). However, overcorrected alignment could induce the progression of arthritis on the non-arthroplasty side. Changes of limb alignment after UKA with both types of bearings (fixed bearing: 24 knees, mobile bearing: 28 knees) were investigated. The mean difference between the preoperative standing femoral-tibial angle (FTA) and postoperative standing FTA was significantly larger in mobile bearing UKA group. In fixed-bearing UKA, there must be some laxity in MCL tension so that a 2-mm tension gauge can be inserted. In mobile-bearing UKA, appropriate MCL tension is needed to prevent bearing dislocation. This difference in MCL tension may have caused the difference in the correction angle between the groups. Copyright © 2016 Elsevier Inc. All rights reserved.

Reactivity of glycyl-amino acids toward hydroxyl radical in neutral aqueous solutions

International Nuclear Information System (INIS)

Masuda, Takahiro; Iwashita, Naomi; Shinohara, Hiroyuki; Kondo, Masaharu

1978-01-01

Rate constants for reactions of hydroxyl radicals with several glycyl-amino acids were determined by a competition method using p-nitrosodimethylailine as a reference compound. For glycyl-aliphatic amino acids, the enhancement of reactivity was observed as compared with the corresponding free amino acids. The reactivity was explained qualitatively in terms of partial reactivities assigned to each C-H bond of the dipeptides. For glycyl-aromatic amino acids, the rate constants were found to be almost equal to those of the corresponding free amino acids. The reactivity of a protein toward hydroxyl radical was well understood by summation of the rate constants, corrected by steric factors, of amino acid residues located on surface of the protein. The enhanced reactivity of the aliphatic peptides was interpreted in terms of the difference in interaction energy between NH 2 - and NH 3 + -forms of an aliphatic amino acid, which was calculated for the system including glycine and hydroxyl radical according to CNDO/2 method. (auth.)

Electrolytic coloration and spectral properties of hydroxyl-doped potassium bromide single crystals

International Nuclear Information System (INIS)

Qi, Lan; Song, Cuiying; Gu, Hongen

2013-01-01

Hydroxyl-doped potassium bromide single crystals are colored electrolytically at various temperatures and voltages by using a pointed cathode and a flat anode. The characteristic OH − spectral band is observed in absorption spectrum of uncolored single crystal. The characteristic O − , OH − , U, V 2 , O 2− −V a + , M L1 , F and M spectral bands are observed simultaneously in absorption spectra of colored single crystals. Current–time curve for electrolytic coloration of hydroxyl-doped potassium bromide single crystal and its relationship with electrolytic coloration processes are given. Production and conversion of color centers are explained. - Highlights: ► We expanded the traditional electrolysis method. ► Hydroxyl-doped potassium bromide crystals were colored electrolytically for the first time. ► Useful V, F and F-aggregate color centers were produced in colored crystals. ► V color centers were produced directly and F as well as F-aggregate color centers indirectly.

Trimeric Hydrogen Bond in Geometrically Frustrated Hydroxyl Cobalt Halogenides

International Nuclear Information System (INIS)

Xiao-Dong, Liu; Masato, Hagihala; Xu-Guang, Zheng; Dong-Dong, Meng; Wan-Jun, Tao; Sen-Lin, Zhang; Qi-Xin, Guo

2011-01-01

The mid-infrared absorption spectra of geometrically frustrated hydroxyl cobalt halogenides Co 2 (OH) 3 Cl and Co 2 (OH) 3 Br are measured by FTIR spectrometers, and the stretching vibrational modes of hydroxyl groups are found to be 3549cm −1 and 3524cm −1 respectively. Through finding their true terminal O-H group stretching vibration frequencies, we obtain 107cm −1 and 99cm −1 red shift caused by the corresponding O-H···Cl and O-H···Br hydrogen bonds. Rarely reported trimeric hydrogen bonds (Co 3 ≡O-H) 3 ···Cl/Br are pointed out to demonstrate the relative weakness of this kind of hydrogen bond which may have a critical effect on the lattice symmetry and magnetic structures. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Modulation of individual steps in group I intron catalysis by a peripheral metal ion.

Science.gov (United States)

Forconi, Marcello; Piccirilli, Joseph A; Herschlag, Daniel

2007-10-01

Enzymes are complex macromolecules that catalyze chemical reactions at their active sites. Important information about catalytic interactions is commonly gathered by perturbation or mutation of active site residues that directly contact substrates. However, active sites are engaged in intricate networks of interactions within the overall structure of the macromolecule, and there is a growing body of evidence about the importance of peripheral interactions in the precise structural organization of the active site. Here, we use functional studies, in conjunction with published structural information, to determine the effect of perturbation of a peripheral metal ion binding site on catalysis in a well-characterized catalytic RNA, the Tetrahymena thermophila group I ribozyme. We perturbed the metal ion binding site by site-specifically introducing a phosphorothioate substitution in the ribozyme's backbone, replacing the native ligands (the pro-R (P) oxygen atoms at positions 307 and 308) with sulfur atoms. Our data reveal that these perturbations affect several reaction steps, including the chemical step, despite the absence of direct contacts of this metal ion with the atoms involved in the chemical transformation. As structural probing with hydroxyl radicals did not reveal significant change in the three-dimensional structure upon phosphorothioate substitution, the effects are likely transmitted through local, rather subtle conformational rearrangements. Addition of Cd(2+), a thiophilic metal ion, rescues some reaction steps but has deleterious effects on other steps. These results suggest that native interactions in the active site may have been aligned by the naturally occurring peripheral residues and interactions to optimize the overall catalytic cycle.

Iron-functionalized Al-SBA-15 for benzene hydroxylation

NARCIS (Netherlands)

Li, Y.; Xia, H.; Fan, F.; Feng, Z.; Santen, van R.A.; Hensen, E.J.M.; Li, Can

2008-01-01

For the first time an ordered mesoporous silica (Fe–Al-SBA-15) with catalytically active isolated Fe surface species for the hydroxylation of benzene with nitrous oxide is prepared by introduction of Fe3+ in the synthesis gel of Al-SBA-15. Graphical abstract image for this article (ID: b717079c)

The Influence of Hydroxylated Carbon Nanotubes on Epoxy Resin Composites

Directory of Open Access Journals (Sweden)

Jiaoxia Zhang

2012-01-01

Full Text Available Hydroxylated multiwall carbon nanotubes (MWNTs/epoxy resin nanocomposites were prepared with ultrasonic dispersion and casting molding. The effect of hydroxylated MWNTs content on reactive activity of composites is discussed. Then the flexural and electrical properties were studied. Transmission electron microscope was employed to characterize the microstructure of nanocomposites. As a result, the reactive activity of nanocomposites obtained increases with the increasing content of MWNTs. When MWNTs content of the composites is 1 wt%, as compared to neat resin, the flexural strength increases from 143 Mpa to 156 MPa, the modulus increases from 3563 Mpa to 3691 MPa, and the volume and surface resistance of nanocomposites decrease by two orders of magnitude, respectively.

Steroid Hydroxylation by Basidiomycete Peroxygenases: a Combined Experimental and Computational Study

Science.gov (United States)

Babot, Esteban D.; del Río, José C.; Cañellas, Marina; Sancho, Ferran; Lucas, Fátima; Guallar, Víctor; Kalum, Lisbeth; Lund, Henrik; Gröbe, Glenn; Scheibner, Katrin; Ullrich, René; Hofrichter, Martin; Martínez, Angel T.

2015-01-01

The goal of this study is the selective oxyfunctionalization of steroids under mild and environmentally friendly conditions using fungal enzymes. With this purpose, peroxygenases from three basidiomycete species were tested for the hydroxylation of a variety of steroidal compounds, using H2O2 as the only cosubstrate. Two of them are wild-type enzymes from Agrocybe aegerita and Marasmius rotula, and the third one is a recombinant enzyme from Coprinopsis cinerea. The enzymatic reactions on free and esterified sterols, steroid hydrocarbons, and ketones were monitored by gas chromatography, and the products were identified by mass spectrometry. Hydroxylation at the side chain over the steroidal rings was preferred, with the 25-hydroxyderivatives predominating. Interestingly, antiviral and other biological activities of 25-hydroxycholesterol have been reported recently (M. Blanc et al., Immunity 38:106–118, 2013, http://dx.doi.org/10.1016/j.immuni.2012.11.004). However, hydroxylation in the ring moiety and terminal hydroxylation at the side chain also was observed in some steroids, the former favored by the absence of oxygenated groups at C-3 and by the presence of conjugated double bonds in the rings. To understand the yield and selectivity differences between the different steroids, a computational study was performed using Protein Energy Landscape Exploration (PELE) software for dynamic ligand diffusion. These simulations showed that the active-site geometry and hydrophobicity favors the entrance of the steroid side chain, while the entrance of the ring is energetically penalized. Also, a direct correlation between the conversion rate and the side chain entrance ratio could be established that explains the various reaction yields observed. PMID:25862224

A review of bear farming and bear trade in Lao People's Democratic Republic

Directory of Open Access Journals (Sweden)

E. Livingstone

2018-01-01

Full Text Available This study reviews the bear farming industry in Lao PDR with the objective of documenting the current number of commercial bear facilities (i.e. captive bear facilities judged to be trading in bear bile and/or bears and bear parts and the number of bears contained within these facilities, noting changes since it was last examined between 2000 and 2012 by Livingstone and Shepherd (2014. We surveyed all known commercial bear facilities and searched for previously unrecorded facilities. We compared our records with Livingstone and Shepherd (2014 and corrected some duplicate records from their study. In 2017, we recorded seven commercial facilities; four dedicated bear farms, and three tiger farms that were reportedly also keeping bears. We found that between 2012 and 2017 the recorded number of dedicated bear farms reduced by two, and the recorded number of tiger farms also keeping bears increased by one. Within the same period, the total number of captive bears among all facilities in Lao PDR hardly changed (+one, but the number of bears within each facility did. The northern facilities, owned by ethnic Chinese, have expanded since 2012, and central and southern facilities have downsized or closed. While bear farming appears to be downsizing in Lao PDR overall, efforts to phase it out are undermined by the expansion of foreign owned facilities in the north, within Special and Specific Economic Zones that largely cater to a Chinese market, and where the Lao government's efforts to enforce laws and protect wildlife appear to be lacking. Closing the facilities in the north will require political will and decisive law enforcement. Keywords: Bear farms, Bear bile, Gall bladder, Urso-deoxycholic acid, Bear bile extraction facilities, Lao PDR, Ursus thibetanus

Administration of polysaccharide from Panax notoginseng prolonged the survival of H22 tumor-bearing mice

Directory of Open Access Journals (Sweden)

Li HY

2016-06-01

Full Text Available Huaiyu Li,1,* Longlong Gu,1,2,* Yuanyuan Zhong,1 Yajuan Chen,1 Lei Zhang,1 Annie R Zhang,3 Robert W Sobol,4,5 Tong Chen,1,6 Jianfeng Li4,5 1Yunnan Key Laboratory of Pharmacology for Natural Products, School of Pharmaceutical Sciences, 2Haiyuan College, Kunming Medical University, Kunming, Yunnan, People’s Republic of China; 3Graduate School of Applied and Professional Psychology, Rutgers, The State University of New Jersey, Piscataway, NJ, 4Department of Oncologic Sciences, 5Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA; 6Yunnan Panax notoginseng (Burk F.H. Chen Biotechnology and Pharmaceutical Engineering Research Center, Kunming, Yunnan, People’s Republic of China *These authors contributed equally to this work Background: Polysaccharides from various sources are being considered potential sources for the treatment of liver cancer. The aim of this study was to investigate the impact of polysaccharide isolated from Panax notoginseng (PPN on the proliferation of H22 liver cancer cells and the survival of the tumor-bearing mice transplanted with H22 cells.Materials and methods: Polysaccharide from PPN was added to the culture medium of mouse hepatoma H22 cells at different doses. Cell proliferation was assayed with a standard MTT assay. Survival rates of tumor-bearing mice were recorded. Peripheral blood lymphocytes were assayed by flow cytometry. Serum interleukin-2 levels in peripheral blood were measured by enzyme-linked immunosorbent assay.Results: Polysaccharide from PPN inhibited the growth of H22 cells and significantly prolonged the survival of tumor-bearing mice. The increase in activated CD4+ T-cells and the elevation of serum interleukin-2 may contribute to the antitumor activity of PPN.Conclusion: PPN has potential antitumor activity for the treatment of liver cancer. Keywords: polysaccharide, Panax notoginseng, liver cancer, immunotherapy, IL-2

Molecular phylogeny and SNP variation of polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus) derived from genome sequences.

Science.gov (United States)

Cronin, Matthew A; Rincon, Gonzalo; Meredith, Robert W; MacNeil, Michael D; Islas-Trejo, Alma; Cánovas, Angela; Medrano, Juan F

2014-01-01

We assessed the relationships of polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus) with high throughput genomic sequencing data with an average coverage of 25× for each species. A total of 1.4 billion 100-bp paired-end reads were assembled using the polar bear and annotated giant panda (Ailuropoda melanoleuca) genome sequences as references. We identified 13.8 million single nucleotide polymorphisms (SNP) in the 3 species aligned to the polar bear genome. These data indicate that polar bears and brown bears share more SNP with each other than either does with black bears. Concatenation and coalescence-based analysis of consensus sequences of approximately 1 million base pairs of ultraconserved elements in the nuclear genome resulted in a phylogeny with black bears as the sister group to brown and polar bears, and all brown bears are in a separate clade from polar bears. Genotypes for 162 SNP loci of 336 bears from Alaska and Montana showed that the species are genetically differentiated and there is geographic population structure of brown and black bears but not polar bears.

Formation of Hydroxylamine from Ammonia and Hydroxyl Radicals

Science.gov (United States)

Krim, Lahouari; Zins, Emilie-Laure

2014-06-01

In the interstellar medium, as well as in icy comets, ammonia may be a crucial species in the first step toward the formation of amino-acids and other prebiotic molecules such as hydroxylamine (NH2OH). It is worth to notice that the NH3/H2 ratio in the ISM is 3 10-5 compared the H2O/H2 one which is only 7 10-5. Using either electron-UV irradiations of water-ammonia ices or successive hydrogenation of solid nitric oxide, laboratory experiments have already shown the feasibility of reactions that may take place on the surface of ice grains in molecular clouds, and may lead to the formation of this precursor. Herein is proposed a new reaction pathway involving ammonia and hydroxyl radicals generated in a microwave discharge. Experimental studies, at 3 and 10 K, in solid phase as well as in neon matrix have shown that this reaction proceed via a hydrogen abstraction, leading to the formation of NH2 radical, that further recombine with hydroxyl radical to form hydroxylamine, under non-energetic conditions.

Thyroid hormone-like and estrogenic activity of hydroxylated PCBs in cell culture

International Nuclear Information System (INIS)

Kitamura, Shigeyuki; Jinno, Norimasa; Suzuki, Tomoharu; Sugihara, Kazumi; Ohta, Shigeru; Kuroki, Hiroaki; Fujimoto, Nariaki

2005-01-01

The thyroid hormone-disrupting activity of hydroxylated PCBs was examined. 4-Hydroxy-2,2',3,4',5,5'-hexachlorobiphenyl (4-OH-2,2',3,4',5,5'-HxCB), 4-hydroxy-3,3',4',5-tetrachlorobiphenyl (4-OH-3,3',4',5-TCB) and 4,4'-dihydroxy-3,3',5,5'-tetrachlorobiphenyl (4,4'-diOH-3,3',5,5'-TCB), which have been detected as metabolites of PCBs in animals and humans, and six other 4-hydroxylated PCBs markedly inhibited the binding of triiodothyronine (1 x 10 -10 M) to thyroid hormone receptor (TR) in the concentration range of 1 x 10 -6 to 1 x 10 -4 M. However, 4-hydroxy-2',4',6'-trichlorobiphenyl (4-OH-2',4',6'-TCB), 3-hydroxy-2,2',5,5'-tetrachlorobiphenyl, 4-hydroxy-2,2',5,5'-tetrachlorobiphenyl, 4-hydroxy-2,3,3',4'-tetrachlorobiphenyl, 2,3',5,5'-tetrachlorobiphenyl and 2,3',4',5,5'-pentachlorodiphenyl did not show affinity for TR. The thyroid hormonal activity of PCBs was also examined using rat pituitary cell line GH3 cells, which grow and release growth hormone in a thyroid hormone-dependent manner. 4-OH-2,2',3,4',5,5'-HxCB, 4,4'-diOH-3,3',5,5'-TCB and 4-OH-3,3',4',5-TCB enhanced the proliferation of GH3 cells and stimulated their production of growth hormone in the concentration range of 1 x 10 -7 to 1 x 10 -4 M, while PCBs which had no affinity for thyroid hormone receptor were inactive. In contrast, only 4-OH-2',4',6'-TCB exhibited a significant estrogenic activity using estrogen-responsive reporter assay in MCF-7 cells. However, the 3,5-dichloro substitution of 4-hydroxylated PCBs markedly decreased the estrogenic activity. These results suggest that, at least for the 17 PCB congeners and hydroxylated metabolites tested, a 4-hydroxyl group in PCBs is essential for thyroid hormonal and estrogenic activities, and that 3,5-dichloro substitution favors thyroid hormonal activity, but not estrogenic activity

New fluorescent probes of the hydroxyl radical: characterisation and modelization of the reactivity of coumarin derivatives with HO

International Nuclear Information System (INIS)

Louit, G.

2005-10-01

The hydroxyl radical is involved in a wide range of different fields, from oxidative stress to atmospheric chemistry. In addition to the study of oxidative damage in biological media, the hydroxyl radical detection allows to perform a dosimetry when it is produced by ionising radiation. The aims of this work have been double: - to improve the detection of the hydroxyl radical by the design of new probes - to improve knowledge on the reactive pathways in which the hydroxyl radical is involved. We have studied the coumarin molecule, as well as 6 derivatives that we have synthesised, as fluorescent probes of the hydroxyl radical. Firstly, fluorescence spectroscopy and HPLC chromatography have allowed the evaluation of the sensibility and selectivity of detection of the probes. Consequently to this study, two applications have been developed, concerning the determination of rate constants by competition kinetics and bidimensional dosimetry. Secondly, we have studied the reactivity of the hydroxyl radical through the regioselectivity of its addition on the aromatic cycle. This problem was addressed by the combined use of experimental methods such as time resolved kinetics and HPLC along with interpretation from classical and ab initio modelization. (author)

Structure, electronic properties, and aggregation behavior of hydroxylated carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

López-Oyama, A. B.; Silva-Molina, R. A.; Ruíz-García, J.; Guirado-López, R. A., E-mail: guirado@ifisica.uaslp.mx [Instituto de Física “Manuel Sandoval Vallarta,” Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí (Mexico); Gámez-Corrales, R. [Departamento de Física, Universidad de Sonora, Apartado Postal 5-088, 83190, Hermosillo, Sonora (Mexico)

2014-11-07

We present a combined experimental and theoretical study to analyze the structure, electronic properties, and aggregation behavior of hydroxylated multiwalled carbon nanotubes (OH–MWCNT). Our MWCNTs have average diameters of ∼2 nm, lengths of approximately 100–300 nm, and a hydroxyl surface coverage θ∼0.1. When deposited on the air/water interface the OH–MWCNTs are partially soluble and the floating units interact and link with each other forming extended foam-like carbon networks. Surface pressure-area isotherms of the nanotube films are performed using the Langmuir balance method at different equilibration times. The films are transferred into a mica substrate and atomic force microscopy images show that the foam like structure is preserved and reveals fine details of their microstructure. Density functional theory calculations performed on model hydroxylated carbon nanotubes show that low energy atomic configurations are found when the OH groups form molecular islands on the nanotube's surface. This patchy behavior for the OH species is expected to produce nanotubes having reduced wettabilities, in line with experimental observations. OH doping yields nanotubes having small HOMO–LUMO energy gaps and generates a nanotube → OH direction for the charge transfer leading to the existence of more hole carriers in the structures. Our synthesized OH–MWCNTs might have promising applications.

Synthesis and properties evaluation of sulfobetaine surfactant with double hydroxyl

Science.gov (United States)

Zhou, Ming; Luo, Gang; Zhang, Ze; Li, Sisi; Wang, Chengwen

2017-09-01

A series of sulfobetaine surfactants {N-[(3-alkoxy-2-hydroxyl)propoxy] ethyl-N,N-dimethyl-N-(2-hydroxyl)propyl sulfonate} ammonium chloride were synthesized with raw materials containing linear saturated alcohol, N,N-dimethylethanolamine, sodium 3-chloro-2-hydroxyl propane sulfonic acid and epichlorohydrin. The molecule structures of sulfobetaine surfactants were characterized by FTIR, 1HNMR and elemental analysis. Surface tension measurements can provide us information about the surface tension at the CMC (γCMC), pC20, Γmax and Amin. The pC20 values of sulfobetaine surfactants increase with the hydrophobic chain length increasing. Amin values of the surfactants decrease with increasing hydrophobic chain length from 10 to 14. The critical micelle concentration (CMC) and surface tension (γCMC) values of the sulfobetaine surfactants decrease with increasing hydrophobic chain length from 10 to 16. The lipophilicity of surfactant was enhanced with the increase of the carbon chain, however, the ability of anti-hard water was weakened. The minimum oil/water interfacial tension of four kinds of sulfobetaine surfactants is 10-2-10-3 mN/m magnitude, which indicates that the synthesized bis-hydroxy sulfobetaine surfactants have a great ability to reduce interfacial tension in the surfactant flooding system. The surface tension (γCMC) values of synthesized surfactants were lower compared with conventional anionic surfactant sodium dodecyl sulfonate.

Teddy Bear Stories

DEFF Research Database (Denmark)

van Leeuwen, Theo; Caldas-Coulthardt, Carmen

2014-01-01

This paper presents a semiotic analysis of a key cultural artefact, the teddy bear. After introducing the iconography of the teddy bear, it analyses different kinds of stories to show how teddy bears are endowed with meaning in everyday life: stories from children's books, reminiscenses by adults...... bears have traditionally centred on interpersonal relations within the nuclear family, but have recently been institutionalized and commercialized....

Les acides gras hydroxylés : agro-tensioactifs aux propriétés moussantes originales

Directory of Open Access Journals (Sweden)

Fameau Anne-Laure

2013-01-01

Full Text Available Surfactants, which are molecules bearing a hydrophobic part and a hydrophilic part, are widely used in many daily life products (detergent, cosmetic, pharmaceutical... because of their foaming properties. Indeed, they spontaneously go to the interface between air and water, which stabilizes the thin water films surrounding air bubbles to obtain foams. Currently, since the most used surfactants come from derivatives from petroleum-based products, their replacement by biomolecules is a major issue in the current context of sustainable development and green chemistry. This could promote the use of molecules from agricultural resources, such as hydroxyl fatty acids that can be extracted from oil or from the tegument of fruits and vegetables, as new agro-based surfactants. Here, we present recent research on the surfactant properties of the 12-hydroxy stearic acid coming from the castor oil. This fatty acid has very advantageous foaming properties compared to conventional synthetic surfactant systems: it enables the production of foams which are at the same time very abundant and, remarkably, stables over a span lasting more than 6 months. Moreover, these foams are thermoresponsive because the foam stability can be easily modulated by a simple modification of the temperature.

Role of hydroxylation modification on the structure and property of reduced graphene oxide/TiO{sub 2} hybrids

Energy Technology Data Exchange (ETDEWEB)

Cao, Shiyi [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Liu, Tiangui, E-mail: tianguiliu@gmail.com [College of Physics and Microelectronics Science, Hunan University, Changsha 410082 (China); Tsang, Yuenhong [Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, 999077 (China); Chen, Chuansheng, E-mail: 1666423158@qq.com [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China)

2016-09-30

Graphical abstract: The structure model and enhancement mechanism of hydroxylation treatment on adsorbability and photocatalytic activity. - Highlights: • Highly-hydroxylated TiO{sub 2}/rGO hybrids can be obtained by UV pre-excitation and microwave method. • Surface hydroxylation induces many defects (Ti{sup 3+}, O vacancy and Ti-OH) and changes color into yellow. • Hydroxylation expands the light absorption up to about 600 nm and benefits to adsorb organic dyes. • ESR reveals the self-accumulation of hydroxyl radicals under the irradiation of UV and visible light. • The photoinduced defects and rGO/TiO{sub 2}@OH-TiO{sub 2} heterojunctions enable the excellent applicability. - Abstract: To extend the spectra response of TiO{sub 2} and enhance its photocatalytic activity, surface modification and catalyst supporter have attracted great attention. In this report, a simple and versatile approach has been developed to hydroxylate the reduced graphene oxide/TiO{sub 2} hybrids (OH-rGO/TiO{sub 2}) by UV-microwave method, and the enhanced mechanisms of hydroxylation were analyzed in details. Experimental results show that TiO{sub 2} nanocrystals@OH-TiO{sub 2} heterojunctions formed on rGO sheets in situ by UV/H{sub 2}O{sub 2} process. Hydroxylation not only can induce many surface defects (Ti{sup 3+}, O vacancy and Ti-OH) on the surface of TiO{sub 2}, but also change the color into yellow and strengthen the interaction between rGO and TiO{sub 2}. OH-rGO/TiO{sub 2} hybrids showed excellent durability for high-concentration dyes, and exhibited strong adsorbability and photocatalytic activity. These enhancements are attributed to the excellent property of rGO and surface defects of TiO{sub 2} induced by hydroxylation, which expand the light absorption up to 600 nm, benefit to the self-dispersion of hybrids, and improve the adsorption dynamic and charge transfer with lower carrier’s recombination.

“Bear-ly” learning: Limits of abstraction in black bear cognition

Directory of Open Access Journals (Sweden)

Jennifer Vonk

2018-02-01

Full Text Available We presented two American black bears (Ursus americanus with a serial list learning memory task, and one of the bears with a matching-to-sample task. After extended training, both bears demonstrated some success with the memory task but failed to generalize the overarching rule of the task to novel stimuli. Matching to sample proved even more difficult for our bear to learn. We conclude that, despite previous success in training bears to respond to natural categories, quantity discriminations, and other related tasks, that bears may possess a cognitive limitation with regards to learning abstract rules. Future tests using different procedures are necessary to determine whether this is a limit of bears’ cognitive capacities, or a limitation of the current tasks as presented. Future tests should present a larger number of varying stimuli. Ideally, bears of various species should be tested on these tasks to demonstrate species as well as individual differences.

Formation of hydroxyl radicals in the human lens is related to the severity of nuclear cataract

DEFF Research Database (Denmark)

Garner, B; Davies, Michael Jonathan; Truscott, R J

2000-01-01

Recent studies have identified specific hydroxylated amino acid oxidation products which strongly suggest the presence of hydroxyl radical (HO.)-damaged proteins in human cataractous lenses. In the present study, the ability of early stage (type II) and advanced (type IV) nuclear cataractous lens...

Synthesis and gas transport properties of hydroxyl-functionalized polyimides with intrinsic microporosity

KAUST Repository

Ma, Xiaohua

2012-05-08

A newly designed diamine monomer, 3,3,3′,3′-tetramethyl-1, 1′-spirobisindane-5,5′-diamino-6,6′-diol, was successfully used to synthesize two types of polyimides for membrane-based gas separation applications. The novel polymers integrate significant microporosity and polar hydroxyl groups, showing the combined features of polymers of intrinsic microporosity (PIMs) and functional polyimides (PIs). They possess high thermal stability, good solubility, and easy processability for membrane fabrication; the resulting membranes exhibit good permeability owing to the intrinsic microporosity introduced by the highly contorted PIM segments as well as high CO 2/CH 4 selectivity that arises from the hydroxyl groups. The membranes show CO 2/CH 4 selectivities of >20 when tested with a 1:1 CO 2/CH 4 mixture for feed pressures up to 50 bar. In addition, the incorporation of hydroxyl groups and microporosity in the polymers enhances their affinity to water, leading to remarkable water sorption capacities of up to 22 wt % at 35 °C and 95% relative humidity. © 2012 American Chemical Society.

Comprehensive database of Manufactured Gas Plant tars. Part C. Heterocyclic and hydroxylated polycyclic aromatic hydrocarbons.

Science.gov (United States)

Gallacher, Christopher; Thomas, Russell; Lord, Richard; Kalin, Robert M; Taylor, Chris

2017-08-15

Coal tars are a mixture of organic and inorganic compounds that were by-products from the manufactured gas and coke making industries. The tar compositions varied depending on many factors such as the temperature of production and the type of retort used. For this reason a comprehensive database of the compounds found in different tar types is of value to understand both how their compositions differ and what potential chemical hazards are present. This study focuses on the heterocyclic and hydroxylated compounds present in a database produced from 16 different tars from five different production processes. Samples of coal tar were extracted using accelerated solvent extraction (ASE) and derivatized post-extraction using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS). The derivatized samples were analysed using two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GCxGC/TOFMS). A total of 865 heterocyclic compounds and 359 hydroxylated polycyclic aromatic hydrocarbons (PAHs) were detected in 16 tar samples produced by five different processes. The contents of both heterocyclic and hydroxylated PAHs varied greatly with the production process used, with the heterocyclic compounds giving information about the feedstock used. Of the 359 hydroxylated PAHs detected the majority would not have been be detected without the use of derivatization. Coal tars produced using different production processes and feedstocks yielded tars with significantly different heterocyclic and hydroxylated contents. The concentrations of the individual heterocyclic compounds varied greatly even within the different production processes and provided information about the feedstock used to produce the tars. The hydroxylated PAH content of the samples provided important analytical information that would otherwise not have been obtained without the use of derivatization and GCxGC/TOFMS. Copyright © 2017 John Wiley & Sons, Ltd.

GAS BEARING

Science.gov (United States)

Skarstrom, C.W.

1960-09-01

A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

MLS/Aura L2 Hydroxyl (OH) Mixing Ratio V002

Data.gov (United States)

National Aeronautics and Space Administration — ML2OH is the EOS Aura Microwave Limb Sounder (MLS) standard product for hydroxyl derived from radiances measured by the THz radiometer. The current version is 2.2....

Microbial carbonylation and hydroxylation of 20(R)-panaxadiol by Aspergillus niger.

Science.gov (United States)

Yan, Bin; Chen, Zhihua; Zhai, Xuguang; Yin, Guibo; Ai, Yafei; Chen, Guangtong

2018-04-01

20(R)-panaxadiol (PD) was metabolised by the fungus Aspergillus niger AS 3.3926 to its C-3 carbonylated metabolite and five other hydroxylated metabolites (1-6). Their structures were elucidated as 3-oxo-20(R)-panaxadiol (1), 3-oxo-7β-hydroxyl- 20(R)-panaxadiol (2), 3-oxo-7β,23α-dihydroxyl-20(R)-panaxadiol (3), 3,12-dioxo- 7β,23β-dihydroxyl-20(R)-panaxadiol (4), 3-oxo-1α,7β-dihydroxyl-20(R)-panaxadiol (5) and 3-oxo-7β,15β-dihydroxyl-20(R)-panaxadiol (6) by spectroscopic analysis. Among them, compounds 2-6 were new compounds. Pharmacological studies revealed that compound 6 exhibited significant anti-hepatic fibrosis activity.

Vasculitic peripheral neuropathy

Directory of Open Access Journals (Sweden)

Mona Amini

2014-02-01

Full Text Available Primary systemic vasculitis in pre-capillary arteries is associated with peripheral neuropathy. In some types of systematic vasculitis about 60 % of patients have peripheral nervous system (PNS involvement. In vasculitic peripheral neuropathies (VPN a necrotizing and inflammatory process leads to narrowing of vasa nervorum lumen and eventually the appearance of ischemic lesions in peripheral nerves. Some features might be suggestive of VPN, like: axonal nerve degeneration, wallerian-like degeneration, and diameter irregularity of nerve. Peripheral nervous system (PNS destruction during systemic vasculitides should be considered, due to its frequency and early occurrence in vasculitis progression. The first line treatment of non systematic VPNs is corticosteroid agents, but these drugs might worsen the VPNs or systemic vasculitis.

Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears.

Science.gov (United States)

Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

2015-03-01

Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we present an analysis of data from a large panel of polar bear and brown bear genomes that includes brown bears from the ABC islands, the Alaskan mainland and Europe. Our results provide clear evidence that gene flow between the two species had a geographically wide impact, with polar bear DNA found within the genomes of brown bears living both on the ABC islands and in the Alaskan mainland. Intriguingly, while brown bear genomes contain up to 8.8% polar bear ancestry, polar bear genomes appear to be devoid of brown bear ancestry, suggesting the presence of a barrier to gene flow in that direction. © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

The effect of hydroxylation on CNT to form Chitosan-CNT composites: A DFT study

International Nuclear Information System (INIS)

Yu, Rui; Ran, Maofei; Wen, Jie; Sun, Wenjing; Chu, Wei; Jiang, Chengfa; He, Zhiwei

2015-01-01

Graphical abstract: - Highlights: • The effect of hydroxylation on CNT to form Chitosan-CNT composites was studied. • The adsorption of Chitosan on CNTs is very weak by electrostatic interactions. • Chitosan loads onto CNT-OH_n via hydrogen-bond interactions. • Chitosan transfers electron to CNT-OH_n and thus improves the reactivity of CNT. - Abstract: The effect of types of CNTs (pristine and hydroxylated) on the synthesis of Chitosan-CNT (CS-CNT) composites was investigated theoretically. The adsorption energy (E_a_d_s) of CS on the pristine CNT and hydroxylated CNTs (CNT-OH_n, n = 1–6) as well as the structural and electronic properties of said composites have been investigated. Results show that the adsorption of CS on CNT and CNT-OH_n is thermodynamically favored. The E_a_d_s of CS on CNTs was calculated to be −20.387 kcal/mol from electrostatic interactions. For CS adsorbed into CNT-OH_n, E_a_d_s ranges from −20.612 to −37.567 kcal/mol. Hydroxyl groups on CNT are the main adsorption sites for CS loading onto CNT-OH_n via hydrogen-bond interactions. The CS-CNT-OH_3 is the most sable composite among tested complexes. The energy gap (ΔE_g_a_p) of CS-CNT-OH_3 was calculated less than pristine CNT and CNT-OH_3, indicative of the composites being more reactive than that of pristine CNTs and CNT-OH_3. It was proved that CS can transfer electron to the hydroxylated CNTs, thus overcoming the drawbacks of CNTs being chemically inert.

The effect of hydroxylation on CNT to form Chitosan-CNT composites: A DFT study

Energy Technology Data Exchange (ETDEWEB)

Yu, Rui [China-America Cancer Research Institute, Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Guangdong Medical University, Dongguan, Guangdong 523808 (China); Department of Chemical Engineering, Sichuan University, Chengdu 610065 (China); Ran, Maofei [College of Chemistry & Environment Protection Engineering, Southwest University for Nationalities, Chengdu 610041, Sichuan (China); Wen, Jie [College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, Sichuan (China); Sun, Wenjing, E-mail: swj_gdmc@163.com [China-America Cancer Research Institute, Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Guangdong Medical University, Dongguan, Guangdong 523808 (China); Chu, Wei; Jiang, Chengfa [Department of Chemical Engineering, Sichuan University, Chengdu 610065 (China); He, Zhiwei, E-mail: zhiweihe688@yahoo.com [China-America Cancer Research Institute, Key Laboratory for Medical Molecular Diagnostics of Guangdong Province, Guangdong Medical University, Dongguan, Guangdong 523808 (China)

2015-12-30

Graphical abstract: - Highlights: • The effect of hydroxylation on CNT to form Chitosan-CNT composites was studied. • The adsorption of Chitosan on CNTs is very weak by electrostatic interactions. • Chitosan loads onto CNT-OH{sub n} via hydrogen-bond interactions. • Chitosan transfers electron to CNT-OH{sub n} and thus improves the reactivity of CNT. - Abstract: The effect of types of CNTs (pristine and hydroxylated) on the synthesis of Chitosan-CNT (CS-CNT) composites was investigated theoretically. The adsorption energy (E{sub ads}) of CS on the pristine CNT and hydroxylated CNTs (CNT-OH{sub n}, n = 1–6) as well as the structural and electronic properties of said composites have been investigated. Results show that the adsorption of CS on CNT and CNT-OH{sub n} is thermodynamically favored. The E{sub ads} of CS on CNTs was calculated to be −20.387 kcal/mol from electrostatic interactions. For CS adsorbed into CNT-OH{sub n}, E{sub ads} ranges from −20.612 to −37.567 kcal/mol. Hydroxyl groups on CNT are the main adsorption sites for CS loading onto CNT-OH{sub n} via hydrogen-bond interactions. The CS-CNT-OH{sub 3} is the most sable composite among tested complexes. The energy gap (ΔE{sub gap}) of CS-CNT-OH{sub 3} was calculated less than pristine CNT and CNT-OH{sub 3}, indicative of the composites being more reactive than that of pristine CNTs and CNT-OH{sub 3}. It was proved that CS can transfer electron to the hydroxylated CNTs, thus overcoming the drawbacks of CNTs being chemically inert.

EFFECT OF CLEARANCE THE BALL BEARINGS ON INCORRECT WORK OF THREE-SUPORT BEARING SHAFT

Directory of Open Access Journals (Sweden)

Jarosław KACZOR

2014-06-01

Full Text Available Durability deep groove ball bearings depends on factors (called attributes design, technological and operational. Among the design features one of the most important is play in the bearings. Polish Norm shows five groups of looseness in the bearings, in which the play range from 0 to 105 microns. Manufacturers of rolling bearings they only play group, which has a bearing data, without giving the exact value of the slack. Aim of this study is to determine how it affects the play in the bearings to work three-bearing shafts, including elasticity and resilience three-bearing shafts.

Peripheral biomarkers revisited: integrative profiling of peripheral samples for psychiatric research.

Science.gov (United States)

Hayashi-Takagi, Akiko; Vawter, Marquis P; Iwamoto, Kazuya

2014-06-15

Peripheral samples, such as blood and skin, have been used for decades in psychiatric research as surrogates for central nervous system samples. Although the validity of the data obtained from peripheral samples has been questioned and other state-of-the-art techniques, such as human brain imaging, genomics, and induced pluripotent stem cells, seem to reduce the value of peripheral cells, accumulating evidence has suggested that revisiting peripheral samples is worthwhile. Here, we re-evaluate the utility of peripheral samples and argue that establishing an understanding of the common signaling and biological processes in the brain and peripheral samples is required for the validity of such models. First, we present an overview of the available types of peripheral cells and describe their advantages and disadvantages. We then briefly summarize the main achievements of omics studies, including epigenome, transcriptome, proteome, and metabolome analyses, as well as the main findings of functional cellular assays, the results of which imply that alterations in neurotransmission, metabolism, the cell cycle, and the immune system may be partially responsible for the pathophysiology of major psychiatric disorders such as schizophrenia. Finally, we discuss the future utility of peripheral samples for the development of biomarkers and tailor-made therapies, such as multimodal assays that are used as a battery of disease and trait pathways and that might be potent and complimentary tools for use in psychiatric research. © 2013 Society of Biological Psychiatry Published by Society of Biological Psychiatry All rights reserved.

Stability, electrochemical behaviors and electronic structures of iron hydroxyl-phosphate

International Nuclear Information System (INIS)

Wang Zhongli; Sun Shaorui; Li Fan; Chen Ge; Xia Dingguo; Zhao Ting; Chu Wangsheng; Wu Ziyu

2010-01-01

Iron hydroxyl-phosphate with a uniform spherical particle size of around 1 μm, a compound of the type Fe 2-y □ y (PO 4 )(OH) 3-3y (H 2 O) 3y-2 (where □ represents a vacancy), has been synthesized by hydrothermal methods. The particles are composed of spheres of diameter -1 and 120 mAh g -1 at current densities of 170 mA g -1 and 680 mA g -1 , respectively. The stability of crystal structure of this material was studied by TGA and XRD which show that the material remains stable at least up to the temperature 200 deg. C. Investigation of the electronic structure of the iron hydroxyl-phosphate by GGA + U calculation has indicated that it has a better electronic conductivity than LiFePO 4 .

Geology and geomorphology of Bear Lake Valley and upper Bear River, Utah and Idaho

Science.gov (United States)

Reheis, M.C.; Laabs, B.J.C.; Kaufman, D.S.

2009-01-01

Bear Lake, on the Idaho-Utah border, lies in a fault-bounded valley through which the Bear River flows en route to the Great Salt Lake. Surficial deposits in the Bear Lake drainage basin provide a geologic context for interpretation of cores from Bear Lake deposits. In addition to groundwater discharge, Bear Lake received water and sediment from its own small drainage basin and sometimes from the Bear River and its glaciated headwaters. The lake basin interacts with the river in complex ways that are modulated by climatically induced lake-level changes, by the distribution of active Quaternary faults, and by the migration of the river across its fluvial fan north of the present lake. The upper Bear River flows northward for ???150 km from its headwaters in the northwestern Uinta Mountains, generally following the strike of regional Laramide and late Cenozoic structures. These structures likely also control the flow paths of groundwater that feeds Bear Lake, and groundwater-fed streams are the largest source of water when the lake is isolated from the Bear River. The present configuration of the Bear River with respect to Bear Lake Valley may not have been established until the late Pliocene. The absence of Uinta Range-derived quartzites in fluvial gravel on the crest of the Bear Lake Plateau east of Bear Lake suggests that the present headwaters were not part of the drainage basin in the late Tertiary. Newly mapped glacial deposits in the Bear River Range west of Bear Lake indicate several advances of valley glaciers that were probably coeval with glaciations in the Uinta Mountains. Much of the meltwater from these glaciers may have reached Bear Lake via groundwater pathways through infiltration in the karst terrain of the Bear River Range. At times during the Pleistocene, the Bear River flowed into Bear Lake and water level rose to the valley threshold at Nounan narrows. This threshold has been modified by aggradation, downcutting, and tectonics. Maximum lake

Bile acid synthesis in man. In vivo activity of the 25-hydroxylation pathway

International Nuclear Information System (INIS)

Duane, W.C.; Pooler, P.A.; Hamilton, J.N.

1988-01-01

During biosynthesis of bile acid, carbons 25-26-27 are removed from the cholesterol side-chain. Side-chain oxidation begins either with hydroxylation at the 26-position, in which case the three-carbon fragment is released as propionic acid, or with hydroxylation at the 25-position, in which case the three-carbon fragment is released as acetone. We have previously shown in the rat that the contribution of the 25-hydroxylation pathway can be quantitated in vivo by measuring production of [ 14 C]acetone from [ 14 C]26-cholesterol. In the present study, we adapted this method to human subjects. 4 d after oral administration of 100 microCi of [ 14 C]26-cholesterol and 1 d after beginning a constant infusion of 16.6 mumol/min unlabeled acetone, three men and two women underwent breath collections. Expired acetone was trapped and purified as the 2,4 dinitrophenylhydrazine derivative. 14 CO 2 was trapped quantitatively using phenethylamine. Specific activity of breath acetone was multiplied by the acetone infusion rate to calculate production of [ 14 C]acetone. [ 14 C]Acetone production averaged 4.9% of total release of 14 C from [ 14 C]26-cholesterol, estimated by 14 CO2 output. The method was validated by showing that [ 14 C]acetone production from [ 14 C]isopropanol averaged 86.9% of the [ 14 C]-isopropanol infusion rate. We conclude that in man, as in the rat, the 25-hydroxylation pathway accounts for less than 5% of bile acid synthesis

Transferrin-bearing polypropylenimine dendrimer for targeted gene delivery to the brain.

Science.gov (United States)

Somani, Sukrut; Blatchford, David R; Millington, Owain; Stevenson, M Lynn; Dufès, Christine

2014-08-28

The possibility of using genes as medicines to treat brain diseases is currently limited by the lack of safe and efficacious delivery systems able to cross the blood-brain barrier, thus resulting in a failure to reach the brain after intravenous administration. On the basis that iron can effectively reach the brain by using transferrin receptors for crossing the blood-brain barrier, we propose to investigate if a transferrin-bearing generation 3-polypropylenimine dendrimer would allow the transport of plasmid DNA to the brain after intravenous administration. In vitro, the conjugation of transferrin to the polypropylenimine dendrimer increased the DNA uptake by bEnd.3 murine brain endothelioma cells overexpressing transferrin receptors, by about 1.4-fold and 2.3-fold compared to that observed with the non-targeted dendriplex and naked DNA. This DNA uptake appeared to be optimal following 2h incubation with the treatment. In vivo, the intravenous injection of transferrin-bearing dendriplex more than doubled the gene expression in the brain compared to the unmodified dendriplex, while decreasing the non-specific gene expression in the lung. Gene expression was at least 3-fold higher in the brain than in any tested peripheral organs and was at its highest 24h following the injection of the treatments. These results suggest that transferrin-bearing polypropylenimine dendrimer is a highly promising gene delivery system to the brain. Copyright © 2014 Elsevier B.V. All rights reserved.

Structure-based engineering of steroidogenic CYP260A1 for stereo- and regioselective hydroxylation of progesterone

NARCIS (Netherlands)

Khatri, Yogan; Jóźwik, Ilona K; Ringle, Michael; Ionescu, Irina Alexandra; Litzenburger, Martin; Hutter, Michael Christopher; Thunnissen, Andy-Mark W H; Bernhardt, Rita

The production of regio- and stereoselectively hydroxylated steroids is of high pharmaceutical interest and can be achieved by cytochrome P450-based biocatalysts. CYP260A1 from Sorangium cellulosum strain So ce56 catalyzes hydroxylation of C19 or C21 steroids at the very unique 1-position. However,

State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics

OpenAIRE

Peter W. Tse; Dong Wang

2017-01-01

Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To exten...

Evaluation of bearing configurations using the single bearing tester in liquid nitrogen

Science.gov (United States)

Jett, T.; Hall, P.; Thom, R.

1991-01-01

Various bearing configurations were tested using the Marshall Space Flight Center single bearing tester with LN2 as the cryogenic coolant. The baseline was one Rocketdyne phase one high pressure oxidizer turbopump (HPOTP) pump end 45-mm bore bearing. The bearing configurations that were tested included a Salox/M cage configuration, a silicon nitride ball configuration, an elongated cage configuration, and a Bray 601 grease configuration.

Hydroxyl radical scavenging activity of peptide from sea cucumber ...

African Journals Online (AJOL)

enzyme complex, sea cucumber protein hydrolysis was carried out to obtain hydrolysates that have hydroxyl-radical-scavenging activity (HRSA). The hydrolytic process was monitored by HRSA and conditions for this process were optimized as follows: pH 6.5, temperature 35°C, 12 mg enzyme complex in a reaction solution ...

Hydroxylative activity of Aspergillus niger towards androst-4-ene and androst-5-ene steroids.

Science.gov (United States)

Świzdor, Alina; Panek, Anna; Milecka-Tronina, Natalia

2017-10-01

Aspergillus niger, one of fungal species most frequently used for experimental and industrial-scale biotransformations of various organic compounds, is generally known to transform steroids at 16β position. In this work, application of the strain A. niger KCH910 to bioconversion of dehydroepiandrosterone (DHEA), androstenediol and testosterone is described, with emphasis on the metabolic steps leading to the products. Evidence from this study indicated that incubated 5-ene steroids underwent bioconversion within two metabolic pathways: oxidation by the action of 3β-HSD (3β-hydroxysteroid dehydrogenase) to 4-ene steroids, and minor allylic hydroxylation to epimeric 7-alcohols. Further transformation of the 3-oxo-4-ene metabolites resulted in non-selective 16-hydroxylation. It is the first report on an A. niger strain able to introduce not only 16β- but also 16α-hydroxyl function into steroids. Copyright © 2017. Published by Elsevier Inc.

Improvement of journal bearing operation at heavy misalignment using bearing flexibility and compliant liners

DEFF Research Database (Denmark)

Thomsen, Kim; Klit, Peder

2012-01-01

A flexure journal bearing design is proposed that will improve operational behaviour of a journal bearing at pronounced misalignment. Using a thermoelastohydrodynamic model, it is shown that the proposed flexure journal bearing has vastly increased the hydrodynamic performance compared to the stiff...... bearing when misaligned. The hydrodynamic performance is evaluated on lubricant film thickness, pressure and temperature. Furthermore, the influence of a compliant bearing liner is investigated and it is found that it increases the hydrodynamic performance when applied to a stiff bearing, whereas...... the liner has practically no influence on the flexure journal bearing's performance....

Peripheral reactions

International Nuclear Information System (INIS)

Greiner, D.

1978-01-01

Peripheral collisions, that is, collisions involving a small amount of overlap of nuclear matter, are discussed including inclusive interactions, the magnitude of the peripheral cross section, fragmentation, a compilation of experiments and available data, limiting fragmentation, factorization, some models, fragment momentum distributions, and future research directions

Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage.

Science.gov (United States)

Hailer, Frank; Kutschera, Verena E; Hallström, Björn M; Klassert, Denise; Fain, Steven R; Leonard, Jennifer A; Arnason, Ulfur; Janke, Axel

2012-04-20

Recent studies have shown that the polar bear matriline (mitochondrial DNA) evolved from a brown bear lineage since the late Pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. Here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. Bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle Pleistocene, about 600 (338 to 934) thousand years ago. This provides more time for polar bear evolution and confirms previous suggestions that polar bears carry introgressed brown bear mitochondrial DNA due to past hybridization. Our results highlight that multilocus genomic analyses are crucial for an accurate understanding of evolutionary history.

Hydroxyl Radical-Mediated Novel Modification of Peptides: N-Terminal Cyclization through the Formation of α-Ketoamide.

Science.gov (United States)

Lee, Seon Hwa; Kyung, Hyunsook; Yokota, Ryo; Goto, Takaaki; Oe, Tomoyuki

2015-01-20

The hydroxyl radical-mediated oxidation of peptides and proteins constitutes a large group of post-translational modifications that can result in structural and functional changes. These oxidations can lead to hydroxylation, sulfoxidation, or carbonylation of certain amino acid residues and cleavage of peptide bonds. In addition, hydroxyl radicals can convert the N-terminus of peptides to an α-ketoamide via abstraction of the N-terminal α-hydrogen and hydrolysis of the ketimine intermediate. In the present study, we identified N-terminal cyclization as a novel modification mediated by a hydroxyl radical. The reaction of angiotensin (Ang) II (DRVYIHPF) and the hydroxyl radical generated by the Cu(II)/ascorbic acid (AA) system or UV/hydrogen peroxide system produced N-terminal cyclized-Ang II (Ang C) and pyruvamide-Ang II (Ang P, CH3COCONH-RVYIHPF). The structure of Ang C was confirmed by mass spectrometry and comparison to an authentic standard. The subsequent incubation of isolated Ang P in the presence of Cu(II)/AA revealed that Ang P was the direct precursor of Ang C. The proposed mechanism involves the formation of a nitrogen-centered (aminyl) radical, which cyclizes to form a five-membered ring containing the alkoxy radical. The subsequent β-scission reaction of the alkoxyl radical results in the cleavage of the terminal CH3CO group. The initial aminyl radical can be stabilized by chelation to the Cu(II) ions. The affinity of Ang C toward the Ang II type 1 receptor was significantly lower than that of Ang II or Ang P. Ang C was not further metabolized by aminopeptidase A, which converts Ang II to Ang III. Hydroxyl radical-mediated N-terminal cyclization was also observed in other Ang peptides containing N-terminal alanine, arginine, valine, and amyloid β 1-11 (DAEFRHDSGYE).

Oxygen activation at the plasma membrane: relation between superoxide and hydroxyl radical production by isolated membranes.

Science.gov (United States)

Heyno, Eiri; Mary, Véronique; Schopfer, Peter; Krieger-Liszkay, Anja

2011-07-01

Production of reactive oxygen species (hydroxyl radicals, superoxide radicals and hydrogen peroxide) was studied using EPR spin-trapping techniques and specific dyes in isolated plasma membranes from the growing and the non-growing zones of hypocotyls and roots of etiolated soybean seedlings as well as coleoptiles and roots of etiolated maize seedlings. NAD(P)H mediated the production of superoxide in all plasma membrane samples. Hydroxyl radicals were only produced by the membranes of the hypocotyl growing zone when a Fenton catalyst (FeEDTA) was present. By contrast, in membranes from other parts of the seedlings a low rate of spontaneous hydroxyl radical formation was observed due to the presence of small amounts of tightly bound peroxidase. It is concluded that apoplastic hydroxyl radical generation depends fully, or for the most part, on peroxidase localized in the cell wall. In soybean plasma membranes from the growing zone of the hypocotyl pharmacological tests showed that the superoxide production could potentially be attributed to the action of at least two enzymes, an NADPH oxidase and, in the presence of menadione, a quinone reductase.

An experimental study of hydroxyl in quartz using infrared spectroscopy and ion microprobe techniques

Energy Technology Data Exchange (ETDEWEB)

Rovetta, M. R.; Blacic, J. D.; Hervig, R. L.; Holloway, J. R.

1989-05-10

We have measured the concentrations of hydroxyl, deuterium, Al, Fe, Li,Na, K, and Rb in a natural quartz crystal before and after hydrothermaltreatment at 1.5 GPa and 800/degree/--1050 /degree/C. We employed microbeam infraredspectroscopy and ion probe techniques to avoid impurities trapped in healedcracks and fluid inclusions that might bias a normal bulk analysis.The /ital f//sub H/sub 2// of our experiments were buffered to thehematite-magnetite-(OH)fluid, nickel-nickel oxide-(OH)fluid, oriron-wustite-(OH)fluid phase assemblages. After hydrothermal treatment,the samples contained local concentrations of hydrogen or deuterium ofseveral hundred atoms/10/sup 6/ Si (the starting crystal contained 45 H/10/sup 6/ Si).We did several experiments with Al/sub 2/O/sub 3/ or RbCl added to the sample chargeand found local Al enrichment where the deuterium concentration was highbut no Rb enrichment. Finally, we measured trace elements and hydroxyl in aquartz sample after plastic deformation in a talc furnace assembly; inregions of the sample containing basal and prismatic deformation lamellae(but no visible healed microcracks at 400/times/ optical magnification)hydroxyl had increased to /similar to/200 oO/10/sup 6/ Si with no increase in Al or Fe.Samples enriched in hydroxyl but not Al (including the plastically strainedsample) gave infrared spectra resembling natural amethyst crystals.

Vibration model of rolling element bearings in a rotor-bearing system for fault diagnosis

Science.gov (United States)

Cong, Feiyun; Chen, Jin; Dong, Guangming; Pecht, Michael

2013-04-01

Rolling element bearing faults are among the main causes of breakdown in rotating machines. In this paper, a rolling bearing fault model is proposed based on the dynamic load analysis of a rotor-bearing system. The rotor impact factor is taken into consideration in the rolling bearing fault signal model. The defect load on the surface of the bearing is divided into two parts, the alternate load and the determinate load. The vibration response of the proposed fault signal model is investigated and the fault signal calculating equation is derived through dynamic and kinematic analysis. Outer race and inner race fault simulations are realized in the paper. The simulation process includes consideration of several parameters, such as the gravity of the rotor-bearing system, the imbalance of the rotor, and the location of the defect on the surface. The simulation results show that different amplitude contributions of the alternate load and determinate load will cause different envelope spectrum expressions. The rotating frequency sidebands will occur in the envelope spectrum in addition to the fault characteristic frequency. This appearance of sidebands will increase the difficulty of fault recognition in intelligent fault diagnosis. The experiments given in the paper have successfully verified the proposed signal model simulation results. The test rig design of the rotor bearing system simulated several operating conditions: (1) rotor bearing only; (2) rotor bearing with loader added; (3) rotor bearing with loader and rotor disk; and (4) bearing fault simulation without rotor influence. The results of the experiments have verified that the proposed rolling bearing signal model is important to the rolling bearing fault diagnosis of rotor-bearing systems.

Polar bears at risk

Energy Technology Data Exchange (ETDEWEB)

Norris, S.; Rosentrater, L.; Eid, P.M. [WWF International Arctic Programme, Oslo (Norway)

2002-05-01

Polar bears, the world's largest terrestrial carnivore, spend much of their lives on the arctic sea ice. This is where they hunt and move between feeding, denning, and resting areas. The world population, estimated at 22,000 bears, is made up of 20 relatively distinct populations varying in size from a few hundred to a few thousand animals. About 60 per cent of all polar bears are found in Canada. In general, the status of this species is stable, although there are pronounced differences between populations. Reductions in the extent and thickness of sea ice has lead the IUCN Polar Bear Specialist Group to describe climate change as one of the major threats facing polar bears today. Though the long-term effects of climate change will vary in different areas of the Arctic, impacts on the condition and reproductive success of polar bears and their prey are likely to be negative. Longer ice-free periods resulting from earlier break-up of sea ice in the spring and later formation in the fall is already impacting polar bears in the southern portions of their range. In Canada's Hudson Bay, for example, bears hunt on the ice through the winter and into early summer, after which the ice melts completely, forcing bears ashore to fast on stored fat until freeze-up in the fall. The time bears have on the ice to hunt and build up their body condition is cut short when the ice melts early. Studies from Hudson Bay show that for every week earlier that ice break-up occurs, bears will come ashore 10 kg lighter and in poorer condition. It is likely that populations of polar bears dividing their time between land and sea will be severely reduced and local extinctions may occur as greenhouse gas emissions continue to rise and sea ice melts. Expected changes in regional weather patterns will also impact polar bears. Rain in the late winter can cause maternity dens to collapse before females and cubs have departed, thus exposing occupants to the elements and to predators. Such

Transient Vibration Prediction for Rotors on Ball Bearings Using Load-dependent Non-linear Bearing Stiffness

Science.gov (United States)

Fleming, David P.; Poplawski, J. V.

2002-01-01

Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus an accurate rotordynamic transient analysis requires bearing forces to be determined at each step of the transient solution. Analyses have been carried out to show the effect of accurate bearing transient forces (accounting for non-linear speed and load dependent bearing stiffness) as compared to conventional use of average rolling-element bearing stiffness. Bearing forces were calculated by COBRA-AHS (Computer Optimized Ball and Roller Bearing Analysis - Advanced High Speed) and supplied to the rotordynamics code ARDS (Analysis of Rotor Dynamic Systems) for accurate simulation of rotor transient behavior. COBRA-AHS is a fast-running 5 degree-of-freedom computer code able to calculate high speed rolling-element bearing load-displacement data for radial and angular contact ball bearings and also for cylindrical and tapered roller beatings. Results show that use of nonlinear bearing characteristics is essential for accurate prediction of rotordynamic behavior.

Local Attitudes towards Bear Management after Illegal Feeding and Problem Bear Activity.

Science.gov (United States)

Dubois, Sara; Fraser, David

2013-09-12

The "pot bears" received international media attention in 2010 after police discovered the intentional feeding of over 20 black bears during the investigation of an alleged marijuana-growing operation in Christina Lake, British Columbia, Canada. A two-phase random digit dialing survey of the community was conducted in 2011 to understand local perspectives on bear policy and management, before and after a summer of problem bear activity and government interventions. Of the 159 households surveyed in February 2011, most had neutral or positive attitudes towards bears in general, and supported the initial decision to feed the food-conditioned bears until the autumn hibernation. In contrast to wildlife experts however, most participants supported relocating the problem bears, or allowing them to remain in the area, ahead of killing; in part this arose from notions of fairness despite the acknowledged problems of relocation. Most locals were aware of the years of feeding but did not report it, evidently failing to see it as a serious form of harm, even after many bears had been killed. This underscores the importance of preventive action on wildlife feeding and the need to narrow the gap between public and expert opinion on the likely effects of relocation versus killing.

Genetic relationships of extant brown bears (Ursus arctos) and polar bears (Ursus maritimus).

Science.gov (United States)

Cronin, Matthew A; MacNeil, Michael D

2012-01-01

Polar bears (Ursus maritimus) and brown bears (Ursus arctos) are closely related species for which extensive mitochondrial and nuclear phylogenetic comparisons have been made. We used previously published genotype data for 8 microsatellite DNA loci from 930 brown bears in 19 populations and 473 polar bears in 16 populations to compare the population genetic relationships of extant populations of the species. Genetic distances (Nei standard distance = 1.157), the proportion of private alleles (52% of alleles are not shared by the species), and Bayesian cluster analysis are consistent with morphological and life-history characteristics that distinguish polar bears and brown bears as different species with little or no gene flow among extant populations.

Peripheral Developing Odontoma or Peripheral Ameloblastic Fibroodontoma: A Rare Challenging Case

Directory of Open Access Journals (Sweden)

Saede Atarbashi Moghadam

2016-01-01

Full Text Available Peripheral odontogenic lesions are considered to be rare within the classification of odontogenic tumors. They share the same microscopic characteristics of their central counterparts. Here, we report an ulcerated mass of the maxillary gingiva that on histopathological examination was diagnosed as peripheral developing odontoma or peripheral ameloblastic fibroodontoma. The diagnosis of this tumor is challenging and may lead to unnecessary treatment.

Hydrogen bonding analysis of hydroxyl groups in glucose aqueous solutions by a molecular dynamics simulation study

International Nuclear Information System (INIS)

Chen, Cong; Li, Wei Zhong; Song, Yong Chen; Weng, Lin Dong; Zhang, Ning

2012-01-01

Molecular dynamics simulations have been performed to investigate hydrogen bonding characteristics of hydroxyl groups in glucose aqueous solutions with different concentrations. The hydrogen bonding abilities and strength of different O and H atom types have been calculated and compared. The acceptor/donor efficiencies have been predicted and it has been found that: (1) O2-HO2 and O3-HO3 are more efficient intramolecular hydrogen bonding acceptors than donors; (2) O1-HO1, O4-HO4 and O6-HO6 are more efficient intramolecular hydrogen bonding donors than acceptors; (5) O1-HO1 and O6-HO6 are more efficient intermolecular hydrogen bonding acceptors than donors while hydroxyl groups O2-HO2 and O4-HO4 are more efficient intermolecular hydrogen bonding donors than acceptors. The hydrogen bonding abilities of hydroxyl groups revealed that: (1) the hydrogen bonding ability of OH2-H w is larger than that of hydroxyl groups in glucose; (2) among the hydroxyl groups in glucose, the hydrogen bonding ability of O6-HO6 is the largest and the hydrogen bonding ability of O4-HO4 is the smallest; (3) the intermolecular hydrogen bonding ability of O6-HO6 is the largest; (4) the order for intramolecular hydrogen bonding abilities (from large to small) is O2-HO2, O1-HO1, O3-HO3, O6-HO6 and O4-HO4

Hydroxyl and water molecule orientations in trypsin: Comparison to molecular dynamics structures

Energy Technology Data Exchange (ETDEWEB)

McDowell, R.S.; Kossiakoff, A.A. [Genentech, Inc., South San Francisco, CA (United States)

1994-12-31

A comparison is presented of experimentally observed hydroxyl and water hydrogens in trypsin determined from neutron density maps with the results of a 140ps molecular dynamics (MD) simulation. Experimental determination of hydrogen and deuterium atom positions in molecules as large as proteins is a unique capability of neutron diffraction. The comparison addresses the degree to which a standard force-field approach can adequately describe the local electrostatic and van der Waals forces that determine the orientations of these hydrogens. Neutron densities, derived from 2.1{Angstrom} D{sub 2}O-H{sub 2}O difference Fourier maps, provide a database of 27 well-ordered hydroxyl hydrogens. Most of the simulated hydroxyl orientations are within a standard deviation of the experimentally-observed positions, including several examples in which both the simulation and the neutron density indicate that a hydroxyl group is shifted from a {open_quote}standard{close_quote} rotamer. For the most highly ordered water molecules, the hydrogen distributions calculated from the trajectory were in good agreement with neutron density; simulated water molecules that displayed multiple hydrogen bonding networks had correspondingly broadened neutron density profiles. This comparison was facilitated by development of a method to construct a pseudo 2{Angstrom} density map based on the hydrogen atom distributions from the simulation. The degree of disorder of internal water molecules is shown to result primarily from the electrostatic environment surrounding that water molecule as opposed to the cavity size available to the molecule. A method is presented for comparing the discrete observations sampled in a dynamics trajectory with the time- averaged data obtained from X-ray or neutron diffraction studies. This method is particularly useful for statically-disordered water molecules, in which the average location assigned from a trajectory may represent a site of relatively low occupancy.

Peripheral Neuropathy and Agent Orange

Science.gov (United States)

... Enter ZIP code here Enter ZIP code here Peripheral Neuropathy and Agent Orange VA presumes Veterans' early-onset ... 10 percent disabling by VA's rating regulations. About peripheral neuropathy Peripheral neuropathy is a condition of the peripheral ...

R+D works for the further development of high temperature reactors. (1) Captive bearing experiments for active magnetic bearings. (2) Captive bearing test for HTR blowers

International Nuclear Information System (INIS)

1991-01-01

When using active magnetic bearings as blower shaft bearings, blower motors and bearings must be protected against mechanical damage in case of faults (example: total electrical supply failure due to the supply cables breaking). So-called captive bearings are provided, in order to be able to shut the blowers down safely in such faults. These captive bearings are roller bearings which are additionally fitted in the area of the blower shaft bearings, to prevent mechanical contact between the blower rotor and stator. As there was little experience available for the given boundary conditions, such as - speed, - acceleration, - bearing load, - bearing dimensions, - ambient conditions, appropriate development and tests had to be carried out. It was important to determine suitable captive bearings and the necessary ambient conditions, which will make it possible to support the failures of the magnetic bearings to be expected in 40 years' operation of the reactor without damage and to meet the requirements of the captive bearings. (orig./GL) [de

EFFECT OF BEARING MACROGEOMETRY ON BEARING PERFORMANCE IN ELASTOHYDRODYNAMIC LUBRICATION

Directory of Open Access Journals (Sweden)

Emin GÜLLÜ

2000-01-01

Full Text Available During manufacturing, ideal dimension and mutual positioning of machine elements proposed in project desing can be achieved only within certain range of tolerances. These tolerances, being classified in two groups, related to micro and macro geometry of machine elements, don't have to effect the functioning of these elements. So, as for all machine elements, investigation of the effects of macro and micro tolerances for journal bearings is important. In this study, we have investigated the effect of macro geometric irregularities of journal bearings on performance characteristics. In this regard, we have studied the change of bearing performance in respect to deviation from ideal circle for an elliptic shaft with small ovality rolling in circular journal bearing.

Properties of the Nafion membrane impregnated with hydroxyl ammonium based ionic liquids

International Nuclear Information System (INIS)

Garaev, Valeriy; Pavlovica, Sanita; Vaivars, Guntars; Kleperis, Janis

2012-01-01

In this work, the Nafion 112 membrane impregnated with nine various hydroxyl ammonium based ionic liquids have been investigated. The used ionic liquids were combined from hydroxyl ammonium cations (2-hydroxyethylammonium/HEA, bis(2- hydroxyethyl)ammonium/BHEA, tris(2-hydroxyethyl)ammonium/THEA) and carboxylate anions (formate, acetate, lactate). The membranes are characterized by conductivity and thermal stability measurements. It was found, that almost all composites have 10 times higher ion conductivity than a pure Nafion 112 at 90 °C in ambient environment due to the higher thermal stability. The thermal stability of Nafion membrane was increased by all studied nine ionic liquids. In this work, only biodegradable ionic liquids were used for composite preparation.

Effect of nitrogen doping of graphene oxide on hydrogen and hydroxyl adsorption

Energy Technology Data Exchange (ETDEWEB)

Min, Byeong June; Jeong, Hae Kyung [Daegu University, Kyungsan (Korea, Republic of)

2014-05-15

We investigate how nitrogen-doping affects the hydrogen (H) and the hydroxyl (OH) adsorption on graphene oxide (GO) and on nitrogen-doped GO (NGO) via pseudopotential plane wave density functional calculations within the local spin density approximation. We find that the nitrogen doping brings about drastic changes in the hydrogen and the hydroxyl adsorption energetics, but its effects depend sensitively on the nitrogen configuration in NGO. The H and the OH adsorption energies are comparable only for pyrrolic NGO. In GO and quarternary NGO, the H adsorption energy is greater than the OH adsorption energy while the trend is reversed in pyridinic NGO. Also, the OH adsorption process is less affected by nitrogen-doping than the H adsorption is.

Footboards: Indigenous and novel method of screening for diabetes peripheral neuropathy – A pilot study

Directory of Open Access Journals (Sweden)

Akram Hussain Bijli

2017-01-01

Full Text Available Background: To validate the effectiveness of indigenously designed “footboard (FB” in early diagnosis of diabetic peripheral neuropathy (PNP by comparing it with Semmes–Weinstein monofilament (SWM and vibration perception (VP. Materials and Methods: Two hundred and forty-four patients with diabetes were examined for PNP using SWM and 128 Hz tuning fork. The findings were compared with indigenously designed FBs with 1, 2, and 3 mm elevations. Results: Out of 108 patients who did not have protective sensation as per SWM, only 10 (9.2% felt 1 mm board bearings, and out of 72 patients who did not feel vibration, only 8 (11.1% felt 1 mm board bearings. Out of 136 patients who had protective sensation, 128 (94.11% felt 2 mm elevated board bearings, and out of 172 patients who had VP, only 152 patients (88.3% felt 2 mm board bearings. With SWM as standard, the sensitivities and specificities, respectively, were 63% and 90% (1 mm board, and 94% and 60% (2 mm board. With VP, the sensitivities and specificities, respectively, were 59% and 90% (1 mm board, and 88% and 61% (2 mm board. Conclusions: FB, which simultaneously tests touch and pressure sensation, shows a high level of performance in detecting at-risk feet. FB may be simple, time-efficient, and inexpensive test for detection of neuropathy and needs further validation in a larger study.

Vascular access in neonatology: peripherally inserted central catheter and peripheral venous catheter

Directory of Open Access Journals (Sweden)

Marcia Lienemann

2014-04-01

The objective of this paper is to present aspects of peripherally inserted central catheter and peripheral venous catheter, highlighting important points in choosing the type of access. For the passage of peripherally inserted central catheter is previously performing specific course necessary, while the primary indication occurs when it is necessary to access the patient's stay for a long period of time. Whereas peripheral venipuncture is the most appropriate in cases of needing an IV line quickly and safely, for the administration of fluids, blood collection, blood transfusion and other.

Passive magnetic bearing configurations

Science.gov (United States)

Post, Richard F [Walnut Creek, CA

2011-01-25

A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

Pristine and thermally-rearranged gas separation membranes from novel o-hydroxyl-functionalized spirobifluorene-based polyimides

KAUST Repository

Ma, Xiaohua

2014-01-01

A novel o-hydroxyl-functionalized spirobifluorene-based diamine monomer, 2,2′-dihydroxyl-9,9′-spiro-bifluorene- 3,3′-diamine (HSBF), was successfully prepared by a universal synthetic method. Two o-hydroxyl-containing polyimides, denoted as 6FDA-HSBF and SPDA-HSBF, were synthesized and characterized. The BET surface areas of 6FDA-HSBF and SPDA-HSBF are 70 and 464 m2 g-1, respectively. To date, SPDA-HSBF exhibits the highest CO2 permeability (568 Barrer) among all hydroxyl-containing polyimides. The HSBF-based polyimides exhibited higher CO2/CH4 selectivity than their spirobifluorene (SBF) analogues (42 for 6FDA-HSBF vs. 27 for 6FDA-SBF) due to an increase in their diffusivity selectivity. Polybenzoxazole (PBO) membranes obtained from HSBF-based polyimide precursors by thermal rearrangement showed enhanced permeability but at the cost of significantly decreased selectivity.

Decomposition of water into highly combustible hydroxyl gas used in ...

African Journals Online (AJOL)

The method proposed involves the decomposition of water into highly combustible hydroxyl gas via electrolysis, which is used in internal combustion engines of electrical generators for electricity generation. The by-product obtained from combustion of this gas is water vapour and oxygen to replenish the atmosphere.

Enhanced electrical properties in solution-processed InGaZnO thin-film transistors by viable hydroxyl group transfer process

Science.gov (United States)

Kim, Do-Kyung; Jeong, Hyeon-Seok; Kwon, Hyeok Bin; Kim, Young-Rae; Kang, Shin-Won; Bae, Jin-Hyuk

2018-05-01

We propose a simple hydroxyl group transfer method to improve the electrical characteristics of solution-processed amorphous InGaZnO (IGZO) thin-film transistors (TFTs). Tuned poly(dimethylsiloxane) elastomer, which has a hydroxyl group as a terminal chemical group, was adhered temporarily to an IGZO thin-film during the solidification step to transfer and supply sufficient hydroxyl groups to the IGZO thin-film. The transferred hydroxyl groups led to efficient hydrolysis and condensation reactions, resulting in a denser metal–oxygen–metal network being achieved in the IGZO thin-film compared to the conventional IGZO thin-film. In addition, it was confirmed that there was no morphological deformation, including to the film thickness and surface roughness. The hydroxyl group transferred IGZO based TFTs exhibited enhanced electrical properties (field-effect mobility of 2.21 cm2 V‑1 s‑1, and on/off current ratio of 106) compared to conventional IGZO TFTs (field-effect mobility of 0.73 cm2 V‑1 s‑1 and on/off current ratio of 105).

Stability, electrochemical behaviors and electronic structures of iron hydroxyl-phosphate

Energy Technology Data Exchange (ETDEWEB)

Wang Zhongli; Sun Shaorui; Li Fan; Chen Ge [College of Environmental and Energy Engineering, Beijing University of Technology, Pingleyuan 100, Chaoyang District, Beijing 100022 (China); Xia Dingguo, E-mail: dgxia@bjut.edu.cn [College of Environmental and Energy Engineering, Beijing University of Technology, Pingleyuan 100, Chaoyang District, Beijing 100022 (China); Zhao Ting; Chu Wangsheng [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); University of Science and Technology of China, Hefei 230026 (China); Wu Ziyu, E-mail: wuzy@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); University of Science and Technology of China, Hefei 230026 (China)

2010-09-01

Iron hydroxyl-phosphate with a uniform spherical particle size of around 1 {mu}m, a compound of the type Fe{sub 2-y}{open_square}{sub y}(PO{sub 4})(OH){sub 3-3y}(H{sub 2}O){sub 3y-2} (where {open_square} represents a vacancy), has been synthesized by hydrothermal methods. The particles are composed of spheres of diameter <100 nm. The compound exhibits good electrochemical performance, with reversible capacities of around 150 mAh g{sup -1} and 120 mAh g{sup -1} at current densities of 170 mA g{sup -1} and 680 mA g{sup -1}, respectively. The stability of crystal structure of this material was studied by TGA and XRD which show that the material remains stable at least up to the temperature 200 deg. C. Investigation of the electronic structure of the iron hydroxyl-phosphate by GGA + U calculation has indicated that it has a better electronic conductivity than LiFePO{sub 4}.

Multi-property characterization chamber for geophysical-hydrological investigations of hydrate bearing sediments

Energy Technology Data Exchange (ETDEWEB)

Seol, Yongkoo, E-mail: Yongkoo.Seol@netl.doe.gov; Choi, Jeong-Hoon; Dai, Sheng [National Energy Technology Laboratory, U.S. Department of Energy, Morgantown, West Virginia 26507 (United States)

2014-08-01

With the increase in the interest of producing natural gas from methane hydrates as well as potential risks of massive hydrate dissociation in the context of global warming, studies have recently shifted from pure hydrate crystals to hydrates in sediments. Such a research focus shift requires a series of innovative laboratory devices that are capable of investigating various properties of hydrate-bearing sediments (HBS). This study introduces a newly developed high pressure testing chamber, i.e., multi-property characterization chamber (MPCC), that allows simultaneous investigation of a series of fundamental properties of HBS, including small-strain stiffness (i.e., P- and S-waves), shear strength, large-strain deformation, stress-volume responses, and permeability. The peripheral coolant circulation system of the MPCC permits stable and accurate temperature control, while the core holder body, made of aluminum, enables X-ray computer tomography scanning to be easily employed for structural and morphological characterization of specimens. Samples of hydrate-bearing sediments are held within a rubber sleeve inside the chamber. The thick sleeve is more durable and versatile than thin membranes while also being much softer than oedometer-type chambers that are incapable of enabling flow tests. Bias introduced by the rubber sleeve during large deformation tests are also calibrated both theoretically and experimentally. This system provides insight into full characterization of hydrate-bearing sediments in the laboratory, as well as pressure core technology in the field.

Multi-property characterization chamber for geophysical-hydrological investigations of hydrate bearing sediments

International Nuclear Information System (INIS)

Seol, Yongkoo; Choi, Jeong-Hoon; Dai, Sheng

2014-01-01

With the increase in the interest of producing natural gas from methane hydrates as well as potential risks of massive hydrate dissociation in the context of global warming, studies have recently shifted from pure hydrate crystals to hydrates in sediments. Such a research focus shift requires a series of innovative laboratory devices that are capable of investigating various properties of hydrate-bearing sediments (HBS). This study introduces a newly developed high pressure testing chamber, i.e., multi-property characterization chamber (MPCC), that allows simultaneous investigation of a series of fundamental properties of HBS, including small-strain stiffness (i.e., P- and S-waves), shear strength, large-strain deformation, stress-volume responses, and permeability. The peripheral coolant circulation system of the MPCC permits stable and accurate temperature control, while the core holder body, made of aluminum, enables X-ray computer tomography scanning to be easily employed for structural and morphological characterization of specimens. Samples of hydrate-bearing sediments are held within a rubber sleeve inside the chamber. The thick sleeve is more durable and versatile than thin membranes while also being much softer than oedometer-type chambers that are incapable of enabling flow tests. Bias introduced by the rubber sleeve during large deformation tests are also calibrated both theoretically and experimentally. This system provides insight into full characterization of hydrate-bearing sediments in the laboratory, as well as pressure core technology in the field

Comparison of fixed-bearing and mobile-bearing total knee arthroplasty after high tibial osteotomy.

Science.gov (United States)

Hernigou, Philippe; Huys, Maxime; Pariat, Jacques; Roubineau, François; Flouzat Lachaniette, Charles Henri; Dubory, Arnaud

2018-02-01

There is no information comparing the results of fixed-bearing total knee replacement and mobile-bearing total knee replacement in the same patients previously treated by high tibial osteotomy. The purpose was therefore to compare fixed-bearing and mobile-bearing total knee replacements in patients treated with previous high tibial osteotomy. We compared the results of 57 patients with osteoarthritis who had received a fixed-bearing prosthesis after high tibial osteotomy with the results of 41 matched patients who had received a rotating platform after high tibial osteotomy. The match was made for length of follow-up period. The mean follow-up was 17 years (range, 15-20 years). The patients were assessed clinically and radiographically. The pre-operative knee scores had no statistically significant differences between the two groups. So was the case with the intra-operative releases, blood loss, thromboembolic complications and infection rates in either group. There was significant improvement in both groups of knees, and no significant difference was observed between the groups (i.e., fixed-bearing and mobile-bearing knees) for the mean Knee Society knee clinical score (95 and 92 points, respectively), or the Knee Society knee functional score (82 and 83 points, respectively) at the latest follow-up. However, the mean post-operative knee motion was higher for the fixed-bearing group (117° versus 110°). In the fixed-bearing group, one knee was revised because of periprosthetic fracture. In the rotating platform mobile-bearing group, one knee was revised because of aseptic loosening of the tibial component. The Kaplan-Meier survivorship for revision at ten years of follow-up was 95.2% for the fixed bearing prosthesis and 91.1% for the rotating platform mobile-bearing prosthesis. Although we did manage to detect significant differences mainly in clinical and radiographic results between the two groups, we found no superiority or inferiority of the mobile-bearing

Hydrodynamic sliding bearings vs. roller bearings. Segmented sliding bearings for higher rotational speed; Hydrodynamische Gleitlager versus Waelzlager. Segmentgleitlager fuer hoehere Drehzahlen

Energy Technology Data Exchange (ETDEWEB)

Hagenhoff, M.; Sauer, M. [Main-Metall-Giesserei Fritz Schorr GmbH und Co. KG, Altenglan (Germany)

2004-10-01

Hydrodynamic sliding bearings are considered only in cases when roller bearings reach their speed limits and there is no other solution. However, this view neglects the fact that there are modern, optimised sliding bearings which have more advantages over roller bearings than should be expected. Many producers of sliding bearings also have computer programs enabling them to offer customised solutions, i.e. optimal adaptation of the bearings to their specific operating conditions. (orig.) [German] Hydrodynamische Gleitlager werden oft erst dann in Betracht gezogen, wenn man an die Drehzahlgrenzen von Waelzlagern stoesst und keine andere sinnvolle Alternative mehr in Frage kommt. Dabei uebersieht man leicht, dass es moderne, optimierte Gleitlagerkonstruktionen gibt, die weitaus haeufiger ihre Staerken im Vergleich zu Waelzlagern ausspielen koennen als zunaechst vermutet. Viele Gleitlagerhersteller haben zudem heute Berechnungsprogramme zur Verfuegung, die eine optimale Anpassung der Lager an die speziellen Betriebsbedingungen erlauben. (orig.)

Hydroxyl group as IR probe to detect the structure of ionic liquid-acetonitrile mixtures

Science.gov (United States)

Xu, Jing; Deng, Geng; Zhou, Yu; Ashraf, Hamad; Yu, Zhi-Wu

2018-06-01

Task-specific ionic liquids (ILs) are those with functional groups introduced in the cations or anions of ILs to bring about specific properties for various tasks. In this work, the hydrogen bonding interactions between a hydroxyl functionalized IL 1-(2-hydroxylethyl)-3-methylimidazolium tetrafluoroborate ([C2OHMIM][BF4]) and acetonitrile were investigated in detail by infrared spectroscopy, excess spectroscopy, two-dimensional correlation spectroscopy, combined with hydrogen nuclear magnetic resonance and density functional theory calculations (DFT). The hydroxyl group rather than C2sbnd H is found to be the main interaction site in the cation. And the ν(Osbnd H) is more sensitive than v(C-Hs) to the environment, which has been taken as an intrinsic probe to reflect the structural change of IL. Examining the region of ν(Osbnd H), by combining excess spectroscopy and DFT calculation, a number of species were identified in the mixtures. Other than the hydrogen bond between a cation and an anion, the hydroxyl group allows the formation of a hydrogen bond between two like-charged cations. The Osbnd H⋯O hydrogen bonding interactions in the hydroxyl-mediated cation-cation complexes are cooperative, while Osbnd H⋯F and C2sbnd H⋯F hydrogen bonding interactions in cation-anion complexes are anti-cooperative. These in-depth studies on the properties of the ionic liquid-acetonitrile mixtures may shed light on exploring their applications as mixed solvents and understanding the nature of doubly ionic hydrogen bonds.

Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears

OpenAIRE

Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

2015-01-01

© 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd. Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we...

The hydroxyl-functionalized magnetic particles for purification of glycan-binding proteins.

Science.gov (United States)

Sun, Xiuxuan; Yang, Ganglong; Sun, Shisheng; Quan, Rui; Dai, Weiwei; Li, Bin; Chen, Chao; Li, Zheng

2009-12-01

Glycan-protein interactions play important biological roles in biological processes. Although there are some methods such as glycan arrays that may elucidate recognition events between carbohydrates and protein as well as screen the important glycan-binding proteins, there is a lack of simple effectively separate method to purify them from complex samples. In proteomics studies, fractionation of samples can help to reduce their complexity and to enrich specific classes of proteins for subsequent downstream analyses. Herein, a rapid simple method for purification of glycan-binding proteins from proteomic samples was developed using hydroxyl-coated magnetic particles coupled with underivatized carbohydrate. Firstly, the epoxy-coated magnetic particles were further hydroxyl functionalized with 4-hydroxybenzhydrazide, then the carbohydrates were efficiently immobilized on hydroxyl functionalized surface of magnetic particles by formation of glycosidic bond with the hemiacetal group at the reducing end of the suitable carbohydrates via condensation. All conditions of this method were optimized. The magnetic particle-carbohydrate conjugates were used to purify the glycan-binding proteins from human serum. The fractionated glycan-binding protein population was displayed by SDS-PAGE. The result showed that the amount of 1 mg magnetic particles coupled with mannose in acetate buffer (pH 5.4) was 10 micromol. The fractionated glycan-binding protein population in human serum could be eluted from the magnetic particle-mannose conjugates by 0.1% SDS. The methodology could work together with the glycan microarrays for screening and purification of the important GBPs from complex protein samples.

The role of human outdoor recreation in shaping patterns of grizzly bear-black bear co-occurrence.

Directory of Open Access Journals (Sweden)

Andrew Ladle

Full Text Available Species' distributions are influenced by a combination of landscape variables and biotic interactions with other species, including people. Grizzly bears and black bears are sympatric, competing omnivores that also share habitats with human recreationists. By adapting models for multi-species occupancy analysis, we analyzed trail camera data from 192 trail camera locations in and around Jasper National Park, Canada to estimate grizzly bear and black bear occurrence and intensity of trail use. We documented (a occurrence of grizzly bears and black bears relative to habitat variables (b occurrence and intensity of use relative to competing bear species and motorised and non-motorised recreational activity, and (c temporal overlap in activity patterns among the two bear species and recreationists. Grizzly bears were spatially separated from black bears, selecting higher elevations and locations farther from roads. Both species co-occurred with motorised and non-motorised recreation, however, grizzly bears reduced their intensity of use of sites with motorised recreation present. Black bears showed higher temporal activity overlap with recreational activity than grizzly bears, however differences in bear daily activity patterns between sites with and without motorised and non-motorised recreation were not significant. Reduced intensity of use by grizzly bears of sites where motorised recreation was present is a concern given off-road recreation is becoming increasingly popular in North America, and can negatively influence grizzly bear recovery by reducing foraging opportunities near or on trails. Camera traps and multi-species occurrence models offer non-invasive methods for identifying how habitat use by animals changes relative to sympatric species, including humans. These conclusions emphasise the need for integrated land-use planning, access management, and grizzly bear conservation efforts to consider the implications of continued access for

The role of human outdoor recreation in shaping patterns of grizzly bear-black bear co-occurrence.

Science.gov (United States)

Ladle, Andrew; Steenweg, Robin; Shepherd, Brenda; Boyce, Mark S

2018-01-01

Species' distributions are influenced by a combination of landscape variables and biotic interactions with other species, including people. Grizzly bears and black bears are sympatric, competing omnivores that also share habitats with human recreationists. By adapting models for multi-species occupancy analysis, we analyzed trail camera data from 192 trail camera locations in and around Jasper National Park, Canada to estimate grizzly bear and black bear occurrence and intensity of trail use. We documented (a) occurrence of grizzly bears and black bears relative to habitat variables (b) occurrence and intensity of use relative to competing bear species and motorised and non-motorised recreational activity, and (c) temporal overlap in activity patterns among the two bear species and recreationists. Grizzly bears were spatially separated from black bears, selecting higher elevations and locations farther from roads. Both species co-occurred with motorised and non-motorised recreation, however, grizzly bears reduced their intensity of use of sites with motorised recreation present. Black bears showed higher temporal activity overlap with recreational activity than grizzly bears, however differences in bear daily activity patterns between sites with and without motorised and non-motorised recreation were not significant. Reduced intensity of use by grizzly bears of sites where motorised recreation was present is a concern given off-road recreation is becoming increasingly popular in North America, and can negatively influence grizzly bear recovery by reducing foraging opportunities near or on trails. Camera traps and multi-species occurrence models offer non-invasive methods for identifying how habitat use by animals changes relative to sympatric species, including humans. These conclusions emphasise the need for integrated land-use planning, access management, and grizzly bear conservation efforts to consider the implications of continued access for motorised

Unbalance Response Prediction for Rotors on Ball Bearings Using Speed and Load Dependent Nonlinear Bearing Stiffness

Science.gov (United States)

Fleming, David P.; Poplawski, J. V.

2003-01-01

Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus an accurate rotordynamic analysis requires that bearing forces corresponding to the actual bearing deflection be utilized. For this work bearing forces were calculated by COBRA-AHS, a recently developed rolling-element bearing analysis code. Bearing stiffness was found to be a strong function of bearing deflection, with higher deflection producing markedly higher stiffness. Curves fitted to the bearing data for a range of speeds and loads were supplied to a flexible rotor unbalance response analysis. The rotordynamic analysis showed that vibration response varied nonlinearly with the amount of rotor imbalance. Moreover, the increase in stiffness as critical speeds were approached caused a large increase in rotor and bearing vibration amplitude over part of the speed range compared to the case of constant bearing stiffness. Regions of bistable operation were possible, in which the amplitude at a given speed was much larger during rotor acceleration than during deceleration. A moderate amount of damping will eliminate the bistable region, but this damping is not inherent in ball bearings.

New insights into the aquatic photochemistry of fluoroquinolone antibiotics: Direct photodegradation, hydroxyl-radical oxidation, and antibacterial activity changes

International Nuclear Information System (INIS)

Ge, Linke; Na, Guangshui; Zhang, Siyu; Li, Kai; Zhang, Peng; Ren, Honglei; Yao, Ziwei

2015-01-01

The ubiquity and photoreactivity of fluoroquinolone antibiotics (FQs) in surface waters urge new insights into their aqueous photochemical behavior. This study concerns the photochemistry of 6 FQs: ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin and enrofloxacin. Methods were developed to calculate their solar direct photodegradation half-lives (t d,E ) and hydroxyl-radical oxidation half-lives (t ·OH,E ) in sunlit surface waters. The t d,E values range from 0.56 min to 28.8 min at 45° N latitude, whereas t ·OH,E ranges from 3.24 h to 33.6 h, suggesting that most FQs tend to undergo fast direct photolysis rather than hydroxyl-radical oxidation in surface waters. However, a case study for levofloxacin and sarafloxacin indicated that the hydroxyl-radical oxidation induced risky photochlorination and resulted in multi-degradation pathways, such as piperazinyl hydroxylation and clearage. Changes in the antibacterial activity of FQs caused by photodegradation in various waters were further examined using Escherichia coli, and it was found that the activity evolution depended on primary photodegradation pathways and products. Primary intermediates with intact FQ nuclei retained significant antibacterial activity. These results are important for assessing the fate and risk of FQs in surface waters. - Highlights: • It is first reported on hydroxyl-radical oxidation of 6 fluoroquinolone antibiotics. • Methods were developed to assess photolysis and oxidation fate in surface waters. • The neutral form reacted faster with hydroxyl radical than protonated forms. • The main oxidation intermediates and transformation pathways were clarified. • The antibacterial activity changes depend on dominant photolysis pathways

Effects of hydroxyl-functionalization and sub-Tg thermal annealing on high pressure pure- and mixed-gas CO2/CH4 separation by polyimide membranes based on 6FDA and triptycene-containing dianhydrides

KAUST Repository

Swaidan, Raja

2015-02-01

A sub-Tg thermally-annealed (250°C, 24h) ultra-microporous PIM-polyimide bearing a 9,10-diisopropyl-triptycene contortion center and hydroxyl-functionalized diamine (2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, APAF) exhibited plasticization resistance up to 50bar for a 1:1 CO2/CH4 feed mixture, with a 9-fold higher CO2 permeability (30Barrer) and 2-fold increase in CO2/CH4 permselectivity (~50) over conventional dense cellulose acetate membranes at 10bar CO2 partial pressure. Interestingly, mixed-gas CO2/CH4 permselectivities were 10-20% higher than those evaluated under pure-gas conditions due to reduction of mixed-gas CH4 permeability by co-permeation of CO2. Gas transport, physisorption and fluorescence studies indicated a sieving pore-structure engaged in inter-chain charge transfer complexes (CTCs), similar to that of low-free-volume 6FDA-APAF polyimide. The isosteric heat of adsorption of CO2 as well as CO2/CH4 solubility selectivities varied negligibly upon replacement of OH with CH3 but CTC formation was hindered, CO2 sorption increased, CO2 permeability increased ~3-fold, CO2/CH4 permselectivity dropped to ~30 and CH4 mixed-gas co-permeation increased. These results suggest that hydroxyl-functionalization did not cause preferential polymer-gas interactions but primarily elicited diffusion-dominated changes owing to a tightened microstructure more resistant to CO2-induced dilations. Solution-processable hydroxyl-functionalized PIM-type polyimides provide a new platform of advanced materials that unites the high selectivities of low-free-volume polymers with the high permeabilities of PIM-type materials particularly for natural gas sweetening applications.

Local Attitudes towards Bear Management after Illegal Feeding and Problem Bear Activity

Directory of Open Access Journals (Sweden)

David Fraser

2013-09-01

Full Text Available The “pot bears” received international media attention in 2010 after police discovered the intentional feeding of over 20 black bears during the investigation of an alleged marijuana-growing operation in Christina Lake, British Columbia, Canada. A two-phase random digit dialing survey of the community was conducted in 2011 to understand local perspectives on bear policy and management, before and after a summer of problem bear activity and government interventions. Of the 159 households surveyed in February 2011, most had neutral or positive attitudes towards bears in general, and supported the initial decision to feed the food-conditioned bears until the autumn hibernation. In contrast to wildlife experts however, most participants supported relocating the problem bears, or allowing them to remain in the area, ahead of killing; in part this arose from notions of fairness despite the acknowledged problems of relocation. Most locals were aware of the years of feeding but did not report it, evidently failing to see it as a serious form of harm, even after many bears had been killed. This underscores the importance of preventive action on wildlife feeding and the need to narrow the gap between public and expert opinion on the likely effects of relocation versus killing.

Involvement of hydroxyl radicals in the release by ionizing radiation of a cell surface nuclease from Micorcoccus radiodurans

International Nuclear Information System (INIS)

Mitchel, R.E.J.

1975-01-01

The ionizing radiation-induced release of a surface exonuclease from Micrococcus radiodurans is to a large extent inhibited by the removal of water. Irradiation of a cell suspension saturated with O 2 (an effective aqueous electron and hydrogen atom scavenger) allows the same release as irradiation in the presence of N 2 . Ethanol (a good hydroxyl radical scavenger) protects the enzyme from release. These data suggest that hydroxyl radicals produced by the radiolysis of water are important releasing agents. Hydroxyl radicals produced by the ultraviolet decomposition of H 2 O 2 were effective in releasing the enzyme

Bearing construction for refrigeration compresssor

Science.gov (United States)

Middleton, Marc G.; Nelson, Richard T.

1988-01-01

A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings.

A semi-analytical bearing model considering outer race flexibility for model based bearing load monitoring

Science.gov (United States)

Kerst, Stijn; Shyrokau, Barys; Holweg, Edward

2018-05-01

This paper proposes a novel semi-analytical bearing model addressing flexibility of the bearing outer race structure. It furthermore presents the application of this model in a bearing load condition monitoring approach. The bearing model is developed as current computational low cost bearing models fail to provide an accurate description of the more and more common flexible size and weight optimized bearing designs due to their assumptions of rigidity. In the proposed bearing model raceway flexibility is described by the use of static deformation shapes. The excitation of the deformation shapes is calculated based on the modelled rolling element loads and a Fourier series based compliance approximation. The resulting model is computational low cost and provides an accurate description of the rolling element loads for flexible outer raceway structures. The latter is validated by a simulation-based comparison study with a well-established bearing simulation software tool. An experimental study finally shows the potential of the proposed model in a bearing load monitoring approach.

The Haber Process Made Efficient by Hydroxylated Graphene

OpenAIRE

Chaban, Vitaly; Prezhdo, Oleg

2016-01-01

The Haber-Bosch process is the main industrial method for producing ammonia from diatomic nitrogen and hydrogen. Very demanding energetically, it uses an iron catalyst, and requires high temperature and pressure. Any improvement of the Haber process will have an extreme scientific and economic impact. We report a significant increase of ammonia production using hydroxylated graphene. Exploiting the polarity difference between N2/H2 and NH3, as well as the universal proton acceptor behavior of...

Drug-induced peripheral neuropathy

DEFF Research Database (Denmark)

Vilholm, Ole Jakob; Christensen, Alex Alban; Zedan, Ahmed

2014-01-01

Peripheral neuropathy can be caused by medication, and various descriptions have been applied for this condition. In this MiniReview, the term 'drug-induced peripheral neuropathy' (DIPN) is used with the suggested definition: Damage to nerves of the peripheral nervous system caused by a chemical...... substance used in the treatment, cure, prevention or diagnosis of a disease. Optic neuropathy is included in this definition. A distinction between DIPN and other aetiologies of peripheral neuropathy is often quite difficult and thus, the aim of this MiniReview is to discuss the major agents associated...

EFFECT OF CLEARANCE THE BALL BEARINGS ON INCORRECT WORK OF THREE-SUPORT BEARING SHAFT

OpenAIRE

Jarosław KACZOR

2014-01-01

Durability deep groove ball bearings depends on factors (called attributes) design, technological and operational. Among the design features one of the most important is play in the bearings. Polish Norm shows five groups of looseness in the bearings, in which the play range from 0 to 105 microns. Manufacturers of rolling bearings they only play group, which has a bearing data, without giving the exact value of the slack. Aim of this study is to determine how it affects the play in the bea...

New insights into the aquatic photochemistry of fluoroquinolone antibiotics: Direct photodegradation, hydroxyl-radical oxidation, and antibacterial activity changes

Energy Technology Data Exchange (ETDEWEB)

Ge, Linke; Na, Guangshui [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Zhang, Siyu [Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Kai [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Zhang, Peng, E-mail: pzhang@nmemc.org.cn [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Ren, Honglei; Yao, Ziwei [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China)

2015-09-15

The ubiquity and photoreactivity of fluoroquinolone antibiotics (FQs) in surface waters urge new insights into their aqueous photochemical behavior. This study concerns the photochemistry of 6 FQs: ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin and enrofloxacin. Methods were developed to calculate their solar direct photodegradation half-lives (t{sub d,E}) and hydroxyl-radical oxidation half-lives (t{sub ·OH,E}) in sunlit surface waters. The t{sub d,E} values range from 0.56 min to 28.8 min at 45° N latitude, whereas t{sub ·OH,E} ranges from 3.24 h to 33.6 h, suggesting that most FQs tend to undergo fast direct photolysis rather than hydroxyl-radical oxidation in surface waters. However, a case study for levofloxacin and sarafloxacin indicated that the hydroxyl-radical oxidation induced risky photochlorination and resulted in multi-degradation pathways, such as piperazinyl hydroxylation and clearage. Changes in the antibacterial activity of FQs caused by photodegradation in various waters were further examined using Escherichia coli, and it was found that the activity evolution depended on primary photodegradation pathways and products. Primary intermediates with intact FQ nuclei retained significant antibacterial activity. These results are important for assessing the fate and risk of FQs in surface waters. - Highlights: • It is first reported on hydroxyl-radical oxidation of 6 fluoroquinolone antibiotics. • Methods were developed to assess photolysis and oxidation fate in surface waters. • The neutral form reacted faster with hydroxyl radical than protonated forms. • The main oxidation intermediates and transformation pathways were clarified. • The antibacterial activity changes depend on dominant photolysis pathways.

Bearing restoration by grinding

Science.gov (United States)

Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

1976-01-01

A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

Impact of Fixed-Bearing and Mobile-Bearing Tibial Insert in Unicondylar Knee Arthroplasty

Directory of Open Access Journals (Sweden)

Mehmet Faruk Çatma

2016-06-01

Full Text Available INTRODUCTION: The aim of the study is to investigate the impact of fixed or mobile-bearing tibial inserts on patellofemoral arthrosis and evaluate which one to be preferred for patients with patellofemoral arthrosis. METHODS: Operated in our clinic between January 2009 and February 2013, 33 with patellofemoral arthritis together with anteromedial compartment arthritis were included in the study. Patellofemoral joints of patients were evaluated according to the scoring system defined by Fulkerson-Shea. RESULTS: Unicondylar knee arthroplasty with fixed-bearing tibial insertsand 22 (66,6% (male: 3, female: 19 and unicondylar knee arthroplasty with mobile-bearing tibial inserts 11 (33,9 % (male: 2, female: 9 were implanted.Average knee flexion was found to be 116,5 (100-135 degrees in 22 patients with mobile-bearing tibial inserts, and 114,5 (95-135 in 11 patients with fixed-bearing tibial inserts. DISCUSSION AND CONCLUSION: Patellofemoral arthrosis is an important factor for unicondylar knee arthroplasty prognosis and one of the determinants of patient satisfaction. Significantly less patellofemoral complaints were seen with UKA with fixed-bearing tibial insert compared to mobile-bearing tibial insert.

Participation of the NO/cGMP/K+ATP pathway in the antinociception induced by Walker tumor bearing in rats

International Nuclear Information System (INIS)

Barbosa, A.L.R.; Pinheiro, C.A.; Oliveira, G.J.; Torres, J.N.L.; Moraes, M.O.; Ribeiro, R.A.; Vale, M.L.; Souza, M.H.L.P.

2012-01-01

Implantation of Walker 256 tumor decreases acute systemic inflammation in rats. Inflammatory hyperalgesia is one of the most important events of acute inflammation. The L-arginine/NO/cGMP/K + ATP pathway has been proposed as the mechanism of peripheral antinociception mediated by several drugs and physical exercise. The objective of this study was to investigate a possible involvement of the NO/cGMP/K + ATP pathway in antinociception induced in Walker 256 tumor-bearing male Wistar rats (180-220 g). The groups consisted of 5-6 animals. Mechanical inflammatory hypernociception was evaluated using an electronic version of the von Frey test. Walker tumor (4th and 7th day post-implantation) reduced prostaglandin E 2 - (PGE 2 , 400 ng/paw; 50 µL; intraplantar injection) and carrageenan-induced hypernociception (500 µg/paw; 100 µL; intraplantar injection). Walker tumor-induced analgesia was reversed (99.3% for carrageenan and 77.2% for PGE 2 ) by a selective inhibitor of nitric oxide synthase (L-NAME; 90 mg/kg, ip) and L-arginine (200 mg/kg, ip), which prevented (80% for carrageenan and 65% for PGE 2 ) the effect of L-NAME. Treatment with the soluble guanylyl cyclase inhibitor ODQ (100% for carrageenan and 95% for PGE 2 ; 8 µg/paw) and the ATP-sensitive K + channel (KATP) blocker glibenclamide (87.5% for carrageenan and 100% for PGE 2 ; 160 µg/paw) reversed the antinociceptive effect of tumor bearing in a statistically significant manner (P < 0.05). The present study confirmed an intrinsic peripheral antinociceptive effect of Walker tumor bearing in rats. This antinociceptive effect seemed to be mediated by activation of the NO/cGMP pathway followed by the opening of KATP channels

Climate Drives Polar Bear Origins

Science.gov (United States)

In their provocative analysis of northern bears (“Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage,” Reports, 20 April, p. 344), F. Hailer et al. use independent nuclear loci to show that polar bears originated during the middle Pleistocene, rather than during t...

Effects of partial hydrogenation, epoxidation, and hydroxylation on the fuel properties of fatty acid methyl esters

Energy Technology Data Exchange (ETDEWEB)

Wadumesthrige, Kapila; Salley, Steven O.; Ng, K.Y. Simon [Department of Chemical Engineering and Materials Science, Wayne State University, 5050 Anthony Wayne Drive, Detroit, MI 48202 (United States)

2009-10-15

The properties of biodiesel depend on the chemical structure of individual fatty acid methyl esters (FAME). In this work the chemical structure of fatty acid chains was modified by catalytic hydrogenation, epoxidation and hydroxylation under controlled conditions. Hydrolysis of ester functionality or oxidation of fatty acid chain was not observed during these reactions. The properties of hydrogenated FAME strongly depend on the hydrogenation time. The total saturated fatty acid (SFA) percentage increased from 29.3% to 76.2% after 2 h of hydrogenation. This hydrogenated FAME showed higher oxidation stability and higher cetane number but poor cold flow properties. Formation of trans FAME was observed during hydrogenation. Both hydroxylation and epoxidation resulted in a decrease of unsaturated fatty acid methyl ester (UFA) fraction. The percentages of total unsaturated FAME decreased 39% in the epoxidation reaction and 44% in the hydroxylation reaction. The addition of hydroxyl groups to the unsaturated regions of the fatty acid chain yields biodiesel with better cold flow properties, increased lubricity and slightly increased oxidative stability. However, epoxy FAME shows some interesting properties such as higher oxidation stability, higher cetane number and acceptable cold flow properties, which met the limits of ASTM D6751 biodiesel specifications. (author)

Monolayer arrangement of fatty hydroxystearic acids on graphite: Influence of hydroxyl groups

Energy Technology Data Exchange (ETDEWEB)

Medina, S. [Laboratorio de Rayos-X, Centro de Investigación Tecnología e Innovación, de la Universidad de Sevilla (CITIUS), Universidad de Sevilla, Avenida Reina Mercedes, 4B. 41012, Sevilla (Spain); Benítez, J.J.; Castro, M.A. [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Avenida Américo Vespucio, 49. 41092, Sevilla (Spain); Cerrillos, C. [Servicio de Microscopía, Centro de Investigación Tecnología e Innovación, de la Universidad de Sevilla (CITIUS), Universidad de Sevilla, Avenida Reina Mercedes, 4B. 41012, Sevilla (Spain); Millán, C. [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Avenida Américo Vespucio, 49. 41092, Sevilla (Spain); Alba, M.D., E-mail: alba@icmse.csic.es [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Avenida Américo Vespucio, 49. 41092, Sevilla (Spain)

2013-07-31

Previous studies have indicated that long-chain linear carboxylic acids form commensurate packed crystalline monolayers on graphite even at temperatures above their melting point. This study examines the effect on the monolayer formation and structure of adding one or more secondary hydroxyl, functional groups to the stearic acid skeleton (namely, 12-hydroxystearic and 9,10-dihydroxystearic acid). Moreover, a comparative study of the monolayer formation on recompressed and monocrystalline graphite has been performed through X-ray diffraction (XRD) and Scanning Tunneling Microscopy (STM), respectively. The Differential Scanning Calorimetry (DSC) and XRD data were used to confirm the formation of solid monolayers and XRD data have provided a detailed structural analysis of the monolayers in good correspondence with obtained STM images. DSC and XRD have demonstrated that, in stearic acid and 12-hydroxystearic acid adsorbed onto graphite, the monolayer melted at a higher temperature than the bulk form of the carboxylic acid. However, no difference was observed between the melting point of the monolayer and the bulk form for 9,10-dihydroxystearic acid adsorbed onto graphite. STM results indicated that all acids on the surface have a rectangular p2 monolayer structure, whose lattice parameters were uniaxially commensurate on the a-axis. This structure does not correlate with the initial structure of the pure compounds after dissolving, but it is conditioned to favor a) hydrogen bond formation between the carboxylic groups and b) formation of hydrogen bonds between secondary hydroxyl groups, if spatially permissible. Therefore, the presence of hydroxyl functional groups affects the secondary structure and behavior of stearic acid in the monolayer. - Highlights: • Hydroxyl functional groups affect structure and behavior of acids in the monolayer. • Acids on the surface have a rectangular p2 monolayer structure. • Lattice parameters of acids are uniaxially

Investigating the Source of Water and/or Hydroxyl on Asteroid (16) Psyche

Science.gov (United States)

Takir, D.; Reddy, V.; Sanchez, J. A.; Shepard, M. K.; Emery, J. P.

2017-12-01

Asteroid (16) Psyche will be visited by the Psyche mission, which was selected by NASA and will be launched in 2022 as the 14th Discovery mission. Psyche is thought to be one of the most massive exposed metallic core in the asteroid belt. The high radar albedos, thermal inertia, and density of Psyche revealed that this asteroid is composed of almost entirely of Fe-Ni metal. Psyche is also characterized by moderately red spectra and the presence of weak features (attributed to silicates) in the visible and near-infrared (NIR) region (0.3-2.5 µm). Recent NIR observations also showed rotational spectral variations indicating a possible change in the metal/silicate ratio on the surface of this asteroid. Additionally, we observed Psyche in the 3-µm spectral region using the long-wavelength cross-dispersed (LXD: 1.9-4.2 µm) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility (IRTF). Our observations revealed that Psyche exhibits a 3-µm feature, more likely attributed to water- and/or hydroxyl molecules. While the source of water and/or hydroxyl on Psyche remains unclear, we proposed a few possible mechanisms for their formation: (1) the water/hydroxyl-rich materials detected on Psyche might have been delivered to its surface by carbonaceous impactors (like on Vesta), (2) Psyche may not be entirely exposed metallic, instead, its surface has a core-mantle boundary of a differentiated body that was disrupted by impacts (e.g., Pallasite-like), or (3) the water/hydroxyl-rich materials detected on Psyche is produced by Solar wind implantation (like on the Moon). In this talk we will discuss these three possible mechanisms and hypotheses and how they can be tested prior to the launch of the Psyche spacecraft using predictive laboratory measurements and modeling, and during the spacecraft encounter with the asteroid using the mission main instruments that will include the multispectral imagers, the gamma-ray and neutron spectrometer, and the dual

Urocanic acid isomers are good hydroxyl radical scavengers: a comparative study with structural analogues and with uric acid

NARCIS (Netherlands)

Kammeyer, A.; Eggelte, T. A.; Bos, J. D.; Teunissen, M. B.

1999-01-01

UV-exposure of the epidermis leads to the isomerisation of trans-UCA into cis-UCA as well as to the generation of hydroxyl radicals. This study shows by means of the deoxyribose degradation test that UCA isomers are more powerful hydroxyl radical scavengers than the other 4-(5-)substituted imidazole

Hydroxyl radical-modified fibrinogen as a marker of thrombosis: the role of iron.

Science.gov (United States)

Lipinski, B; Pretorius, E

2012-07-01

Excessive free iron in blood and in organ tissues (so called iron overload) has been observed in degenerative diseases such as atherosclerosis, cancer, neurological, and certain autoimmune diseases, in which fibrin-like deposits are also found. Although most of the body iron is bound to hemoglobin and myoglobin in a divalent ferrous form, a certain amount of iron exists in blood as a trivalent (ferric) ion. This particular chemical state of iron has been shown to be toxic to the human body when not controlled by endogenous and/or dietary chelating agents. Experiments described in this paper show for the first time that ferric ions (Fe(3+)) can generate hydroxyl radicals without participation of any redox agent, thus making it a special case of the Fenton reaction. Ferric chloride was also demonstrated to induce aggregation of purified fibrinogen at the same molar concentrations that were used for the generation of hydroxyl radicals. Iron-aggregated fibrinogen, by contrast to native molecule, could not be dissociated into polypeptide subunit chains as shown in a polyacrylamide gel electrophoresis. The mechanism of this phenomenon is very likely based on hydroxyl radical-induced modification of fibrinogen tertiary structure with the formation of insoluble aggregates resistant to enzymatic and chemical degradations. Soluble modified fibrinogen species can be determined in blood of thrombotic patients by the reaction with protamine sulfate and/or by scanning electron microscopy. In view of these findings, it is postulated that iron-induced alterations in fibrinogen structure is involved in pathogenesis of certain degenerative diseases associated with iron overload and persistent thrombosis. It is concluded that the detection of hydroxyl radical-modified fibrinogen may be utilized as a marker of a thrombotic condition in human subjects.

Fabrication and characterisation of fluidic based memristor sensor for liquid with hydroxyl group

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Nor Shahanim Mohamad Hadis

2017-06-01

Full Text Available Two types of memristor sensor were fabricated using two different TiO2 deposition methods of sputtering and sol-gel spin coating. The surface morphology of the sensors and the behaviour of the sensors were analysed by using scanning electron microscopy with energy dispersive x-ray system and I-V characterisation system respectively. The sensors were applied with liquid with hydroxyl group to check the capability of this sensor in sensing different concentration of hydroxyl ion inside the liquid. For that purpose, d-glucose liquid with four concentrations of 10mM, 20mM, 30mM and 40mM were chosen. The liquids dispensed onto the TiO2 surface to act as sensing material. The TiO2 surface was initially covered with polydimethylsiloxane to control the liquid. The sensing capability of the sensors was determined via the current-voltage measurement and off-on resistance ratio. The sensitivity of the sensors was analysed from the off-on resistance ratio analysis. Type II memristor sensor which was fabricated using sol-gel spin coating technique recorded high sensitivity of 120.65 (mM−1, while Type I sensor fabricated using the sputtering technique recorded low sensitivity of 0.035 (mM−1. However, SEM-EDX image illustrated that the sputtering technique produced more uniform TiO2 thin film than sol-gel spin coating technique with larger atomic number of oxygen through the sol-gel spin coating technique. This indicates Type II sensor that has large number of oxygen atom produced more reaction with hydroxyl ion inside the liquid. While, Type I sensor produced less reaction compared with Type II and thus produced smaller off-on resistance ratio. Keywords: Fluidic based memristor, Hydroxyl ion, I-V characteristics, Off-on resistance ratio

Cytochemical and x-ray microanalysis studies of intracellular calcium pools in scale-bearing cells of the coccolithophorid emiliana huxleyi

International Nuclear Information System (INIS)

Wal, P. van der; Bruijn, W.C. de; Westbroek, P.

1985-01-01

Emiliania huxleyi is a coccolithophorid with a life cycle including a stage characterized by the occurrence of a scale-bearing cell type. The scales are composed of organic material and are produced in the cisternae of the Golgi apparatus. The present report deals with the ultrastructural calcium localization in scale-bearing cells using cation-precipitating agents. Cations were precipitated either with potassium carbonate, or potassium phosphate, and then with potassium pyroantimonate. The distribution of electron-opaque deposits was the same when visualized by all four techniques. The most extensive deposits occurred in the Golgi apparatus, the 'peripheral space' (a cellular compartment totally encompassing the protoplast), the multivesicular bodies, and the cell vacuole. X-ray microanalysis revealed that calcium was a constituent of the electron-opaque deposits. The uptake and transport of calcium, as universal functions of the Golgi apparatus, are discussed. (Author)

Diffusion of hydroxyl ions from calcium hydroxide and Aloe vera pastes.

Science.gov (United States)

Batista, Victor Eduardo de Souza; Olian, Douglas Dáquila; Mori, Graziela Garrido

2014-01-01

This study evaluated the diffusion through the dentinal tubules of hydroxyl ions from different calcium hydroxide (CH) pastes containing Aloe vera. Sixty single-rooted bovine teeth were used. The tooth crowns were removed, the root canals were instrumented and the specimens were assigned to 4 groups (n=15) according to the intracanal medication: Group CH/S - CH powder and saline paste; Group CH/P - CH powder and propylene glycol paste; Group CH/A - calcium hydroxide powder and Aloe vera gel paste; Group CH/A/P - CH powder, Aloe vera powder and propylene glycol paste. After placement of the root canal dressings, the teeth were sealed coronally and apically with a two-step epoxy adhesive. The teeth were placed in identified flasks containing deionized water and stored in an oven with 100% humidity at 37 °C. After 3 h, 24 h, 72 h, 7 days, 15 days and 30 days, the deionized water in the flasks was collected and its pH was measured by a pH meter. The obtained data were subjected to statistical analysis at a significance level of 5%. The results demonstrated that all pastes provided diffusion of hydroxyl ions through the dentinal tubules. The combination of Aloe vera and CH (group CH/A) provided a constant release of calcium ions. Group CH/A/P showed the highest pH at 24 and 72 h. In conclusion, the experimental pastes containing Aloe vera were able to enable the diffusion of hydroxyl ions through the dentinal tubules.

Mechanism of the N-Hydroxylation of Primary and Secondary Amines by Cytochrome P450

DEFF Research Database (Denmark)

Seger, Signe T.; Rydberg, Patrik; Olsen, Lars

2015-01-01

Cytochrome P450 enzymes (CYPs) metabolize alkyl- and arylamines, generating several different products. For the primary and secondary amines, some of these reactions result in hydroxylated amines, which may be toxic. Thus, when designing new drugs containing amine groups, it is important to be able...... to predict if a given compound will be a substrate for CYPs, in order to avoid toxic metabolites, and hence to understand the mechanism that is utilized by CYPs. Two possible mechanisms, for the N-hydroxylation of primary and secondary amines mediated by CYPs, are studied by density functional theory (DFT...

Activity of Oligoresveratrols from Stem Bark of Hopea mengarawan (Dipterocarpaceae as Hydroxyl Radical Scavenger

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SRI ATUN

2006-06-01

Full Text Available Four oligoresveratrols ranging from dimer to tetramer, isolated from stem bark of Hopea mengarawan (Dipterocarpaceae plants were tested for their activity as hydroxyl radical scavenger. The activity of these compounds was evaluated against the 2-deoxyribose degradation induced by the hydroxyl radical generated via a Fenton-type reaction. Result showed that balanocarpol, heimiol A, vaticanol G, and vaticanol B had IC50 3.83; 15.44; 2.01; and 4.71 µM, respectively. These results suggest that oligoresveratrols from stem bark of H. mengarawan maybe useful as potential sources of natural antioxidants.

Determining the local origin of hydroxyl radical generation during phacoemulsification.

Science.gov (United States)

Aust, Steven D; Terry, Scott; Hebdon, Thomas; Gunderson, Broc; Terry, Michael; Dimalanta, Ramon

2011-06-01

To determine the local origin of hydroxyl radicals during phacoemulsification using an ultrasonic phacoemulsification device that includes longitudinal and torsional modalities. Chemistry and Biochemistry Department, Utah State University, Logan, Utah, USA. Experimental study. Experiments were conducted using the Infiniti Vision System and Ozil handpiece. Hydroxyl radical concentrations during longitudinal and torsional phacoemulsification were quantitated as malondialdehyde (MDA) determined spectrophotometrically using the deoxyribose assay. The difference between the total concentration found in the aspirated solution at steady-state concentrations and the pre-aspirate levels deductively determined the concentration of MDA formed along the interior of the sonicating tip. The time to reach 50% of steady state as a function of reaction vessel volume was determined. The mean maximum for torsional ultrasound at 100% amplitude was 7.70 nM ± 0.38 (SD), 91.1% of which was generated outside the tip. During longitudinal ultrasound at 100% power, MDA concentration in the aspirated solution was 29.5 ± 0.3 nM, 71.6% of which was generated outside the tip. The time (seconds) to reach 50% of maximum for longitudinal ultrasound using 5 mL, 10 mL, and 20 mL reaction vessels was 12.6 ± 1.5, 21.0 ± 1.5, and 25.3 ± 3.4, respectively. Although a significantly greater proportion of the hydroxyl radicals generated during ultrasound modality were formed outside the phaco tip (91.1% torsional; 71.6% longitudinal), torsional ultrasound generated only about one-fourth the amount of MDA as longitudinal ultrasound in total and about one-third that generated outside the tip (7.02 nM versus 21.1 nM). No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Methemoglobinemia Hemotoxicity of Some Antimalarial 8-Aminoquinoline Analogues and Their Hydroxylated Derivatives: Density Functional Theory Computation of Ionization Potentials.

Science.gov (United States)

Ding, Yuanqing; Liu, Haining; Tekwani, Babu L; Nanayakkara, N P Dhammika; Khan, Ikhlas A; Walker, Larry A; Doerksen, Robert J

2016-07-18

The administration of primaquine (PQ), an essential drug for the treatment and radical cure of malaria, can lead to methemoglobin formation and life-threatening hemolysis for glucose-6-phosphate dehydrogenase deficient patients. The ionization potential (IP, a quantitative measure of the ability to lose an electron) of the metabolites generated by antimalarial 8-aminoquinoline (8-AQ) drugs like PQ has been believed to be correlated in part to this methemoglobinemia hemotoxicity: the lower the IP of an 8-AQ derivative, the higher the concentration of methemoglobin generated. In this work, demethoxylated primaquine (AQ02) was employed as a model, by intensive computation at the B3LYP-SCRF(PCM)/6-311++G**//B3LYP/6-31G** level in water, to study the effects of hydroxylation at various positions on the ionization potential. Compared to the parent AQ02, the IPs of AQ02's metabolites hydroxylated at N1', C5, and C7 were lower by 61, 30, and 19 kJ/mol, respectively, while differences in the IP relative to PQ were small for hydroxylation at all other positions. The C6 position, at which the IP of the hydroxylated metabolite was greater than that of AQ02, by 2 kJ/mol, was found to be unique. Several literature and proposed 8-AQ analogues were studied to evaluate substituent effects on their potential to generate methemoglobin, with the finding that hydroxylations at N1' and C5 contribute the most to the potential hemotoxicity of PQ-based antimalarials, whereas hydroxylation at C7 has little effect. Phenoxylation at C5 in PQ-based 8-AQs can block the hydroxylation at C5 and reduce the potential for methemoglobin generation, while -CF3 and chlorines attached to the phenolic ring can further reduce the risk. The H-shift at N1' during the cationization of hydroxylated metabolites of 8-AQs sharply decreased their IPs, but this effect can be significantly reduced by the introduction of an electron-withdrawing group to the quinoline core. The results and this approach may be

Effect of Bulky and Hydroxyl Groups on Gas Separation Performance of Polyimide Membranes.

Science.gov (United States)

Lee, Bo Mi; Kim, Deuk Ju; Nam, Sang Yong

2015-03-01

A series of polyimides were synthesized by a polycondensation reaction using various aromatic dianhydrides and diamines containing bulky cardo and hydroxyl groups. The imidization and chemical structure of the polyimides were confirmed by NMR and FT-IR. The thermal and gas properties of the polyimides were measured by time-lag, XRD, TGA, and DSC studies. The polyimides showed excellent solubility in common organic solvents and high thermal stability. The CO2 selectivity of HPI membrane was higher than traditional polyimides. In particular, the incorporation of hydroxyl groups improved the CO2 permeability of the polyimide due to increased carbon dioxide solubility. The HPI was thermally converted to polybenzoxazole (PBO) at 450 °C.

Ancestral polymorphisms and sex-biased migration shaped the demographic history of brown bears and polar bears.

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Shigeki Nakagome

Full Text Available Recent studies have reported discordant gene trees in the evolution of brown bears and polar bears. Genealogical histories are different among independent nuclear loci and between biparentally inherited autosomal DNA (aDNA and matrilineal mitochondrial DNA (mtDNA. Based on multi-locus genomic sequences from aDNA and mtDNA, we inferred the population demography of brown and polar bears and found that brown bears have 6 times (aDNA or more than 14 times (mtDNA larger population sizes than polar bears and that polar bear lineage is derived from within brown bear diversity. In brown bears, the effective population size ratio of mtDNA to aDNA was at least 0.62, which deviated from the expected value of 0.25, suggesting matriarchal population due to female philopatry and male-biased migration. These results emphasize that ancestral polymorphisms and sex-biased migration may have contributed to conflicting branching patterns in brown and polar bears across aDNA genes and mtDNA.

Ancestral polymorphisms and sex-biased migration shaped the demographic history of brown bears and polar bears.

Science.gov (United States)

Nakagome, Shigeki; Mano, Shuhei; Hasegawa, Masami

2013-01-01

Recent studies have reported discordant gene trees in the evolution of brown bears and polar bears. Genealogical histories are different among independent nuclear loci and between biparentally inherited autosomal DNA (aDNA) and matrilineal mitochondrial DNA (mtDNA). Based on multi-locus genomic sequences from aDNA and mtDNA, we inferred the population demography of brown and polar bears and found that brown bears have 6 times (aDNA) or more than 14 times (mtDNA) larger population sizes than polar bears and that polar bear lineage is derived from within brown bear diversity. In brown bears, the effective population size ratio of mtDNA to aDNA was at least 0.62, which deviated from the expected value of 0.25, suggesting matriarchal population due to female philopatry and male-biased migration. These results emphasize that ancestral polymorphisms and sex-biased migration may have contributed to conflicting branching patterns in brown and polar bears across aDNA genes and mtDNA.

Bearing for liquid metal pump

International Nuclear Information System (INIS)

Dickinson, R.J.; Pennell, W.E.; Wasko, J.

1984-01-01

A liquid metal pump bearing support comprises a series of tangentially oriented spokes that connect the bearing cylinder to the pump internals structure. The spokes may be arranged in a plurality of planes extending from the bearing cylinder to the pump internals with the spokes in one plane being arranged alternately with those in the next plane. The bearing support structure provides the pump with sufficient lateral support for the bearing structure together with the capability of accommodating differential thermal expansion without adversely affecting pump performance

Ultra-precision bearings

CERN Document Server

Wardle, F

2015-01-01

Ultra-precision bearings can achieve extreme accuracy of rotation, making them ideal for use in numerous applications across a variety of fields, including hard disk drives, roundness measuring machines and optical scanners. Ultraprecision Bearings provides a detailed review of the different types of bearing and their properties, as well as an analysis of the factors that influence motion error, stiffness and damping. Following an introduction to basic principles of motion error, each chapter of the book is then devoted to the basic principles and properties of a specific type of bearin

Watchable Wildlife: The Black Bear

Science.gov (United States)

Lynn L. Rogers

1992-01-01

Black bears are the bears people most often encounter. Black bears live in forests over much of North America, unlike grizzlies that live only in Alaska, northern and western Canada, and the northern Rocky Mountains. This brochure presents the latest information on black bear life and how this species responds to an ever-increasing number of campers, hikers, and...

Bioaccumulation and biotransformation of brominated and chlorinated contaminants and their metabolites in ringed seals (Pusa hispida) and polar bears (Ursus maritimus) from East Greenland.

Science.gov (United States)

Letcher, Robert J; Gebbink, Wouter A; Sonne, Christian; Born, Erik W; McKinney, Melissa A; Dietz, Rune

2009-11-01

We report on the comparative bioaccumulation, biotransformation and/or biomagnification from East Greenland ringed seal (Pusa hispida) blubber to polar bear (Ursus maritimus) tissues (adipose, liver and brain) of various classes and congeners of persistent chlorinated and brominated contaminants and metabolic by-products: polychlorinated biphenyls (PCBs), chlordanes (CHLs), hydroxyl (OH-) and methylsulfonyl (MeSO(2)-) PCBs, polybrominated biphenyls (PBBs), OH-PBBs, polybrominated diphenyl ether (PBDE) and hexabromocyclododecane (HBCD) flame retardants and OH- and methoxyl (MeO-) PBDEs, 2,2-dichloro-bis(4-chlorophenyl)ethene (p,p'-DDE), 3-MeSO(2)-p,p'-DDE, pentachlorophenol (PCP) and 4-OH-heptachlorostyrene (4-OH-HpCS). We detected all of the investigated contaminants in ringed seal blubber with high frequency, the main diet of East Greenland bears, with the exception of OH-PCBs and 4-OH-HpCS, which indicated that these phenolic contaminants were likely of metabolic origin and formed in the bears from accumulated PCBs and octachlorostyrene (OCS), respectively, rather than being bioaccumulated from a seal blubber diet. For all of the detectable sum of classes or individual organohalogens, in general, the ringed seal to polar bear mean BMFs for SigmaPCBs, p,p'-DDE, SigmaCHLs, SigmaMeSO(2)-PCBs, 3-MeSO(2)-p,p'-DDE, PCP, SigmaPBDEs, total-(alpha)-HBCD, SigmaOH-PBDEs, SigmaMeO-PBDEs and SigmaOH-PBBs indicated that these organohalogens bioaccumulate, and in some cases there was tissue-specific biomagnification, e.g., BMFs for bear adipose and liver ranged from 2 to 570. The blood-brain barrier appeared to be effective in minimizing brain accumulation as BMFs were bear tissues appeared to be mainly accumulated from the seal blubber rather than being metabolic formed from PBDEs in the bears. In vitro PBDE depletion assays using polar bear hepatic microsomes, wherein the rate of oxidative metabolism of PBDE congeners was very slow, supported the probability that accumulation

Propylthiouracil and peripheral neuropathy

Directory of Open Access Journals (Sweden)

Valentina Van Boekel

1992-06-01

Full Text Available Peripheral neuropathy is a rare manifestation in hyperthyroidism. We describe the neurological manifestations of a 38 year old female with Graves' disease who developed peripheral neuropathy in the course of her treatment with propylthiouracil. After the drug was tapered off, the neurological signs disappeared. Therefore, we call attention for a possible toxic effect on peripheral nervous system caused by this drug.

Active magnetic bearings used as exciters for rolling element bearing outer race defect diagnosis.

Science.gov (United States)

Xu, Yuanping; Di, Long; Zhou, Jin; Jin, Chaowu; Guo, Qintao

2016-03-01

The active health monitoring of rotordynamic systems in the presence of bearing outer race defect is considered in this paper. The shaft is assumed to be supported by conventional mechanical bearings and an active magnetic bearing (AMB) is used in the mid of the shaft location as an exciter to apply electromagnetic force to the system. We investigate a nonlinear bearing-pedestal system model with the outer race defect under the electromagnetic force. The nonlinear differential equations are integrated using the fourth-order Runge-Kutta algorithm. The simulation and experimental results show that the characteristic signal of outer race incipient defect is significantly amplified under the electromagnetic force through the AMBs, which is helpful to improve the diagnosis accuracy of rolling element bearing׳s incipient outer race defect. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Mechanisms of electron transfer from structrual Fe(II) in reduced nontronite to oxygen for production of hydroxyl radicals

Science.gov (United States)

Yuan, Songhu; Liu, Xixiang; Liao, Wenjuan; Zhang, Peng; Wang, Xiaoming; Tong, Man

2018-02-01

Production of hydroxyl radicals (radOH) has been recently revealed upon oxygenation of sediments in redox-dynamic subsurface environments. In particular, Fe(II)-bearing clay minerals are the major sediment components contributing to radOH production upon oxygenation, and the produced radOH can oxidize contaminants and inactivate bacteria. Whereas, the mechanisms of radOH production from oxygenation of Fe(II)-bearing clay minerals remain elusive. The objectives of this study were to identify the structural variation of Fe(II) entities during the oxidation of Fe(II)-bearing clay minerals by O2, and to unravel the mechanisms of electron transfer within the mineral structure and from mineral to O2 for radOH production. Nontronite (NAu-2, 23% Fe) which was chemically reduced to 54.5% Fe(II) in total Fe was used as a model Fe(II)-bearing clay mineral. Production of radOH and oxidation of Fe(II) were measured during the oxidation of reduced NAu-2 by O2. A wide spectrum of spectroscopic techniques, including Fourier transform infrared spectroscopy (FTIR), Fe K-edge X-ray absorption spectroscopy (XAS), Mössbauer spectra, and X-ray photoelectron spectroscopy (XPS), were employed to explore the structural variation of Fe(II) entities in NAu-2 and the electron transfer within NAu-2 and from NAu-2 to O2. For 180 min oxidation of 1 g/L reduced NAu-2, a biphasic radOH production was observed, being quick within the initial 15 min and slow afterwards. Production of radOH correlates well with oxidation of Fe(II) in the reduced NAu-2. Within the initial 15 min, trioctahedral Fe(II)-Fe(II)-Fe(II) entities and edge Fe(II) in the reduced NAu-2 were preferentially and quickly oxidized, and electrons from the interior Fe(II)-Fe(II)-Fe(II) entities were most likely ejected from the basal siloxane plane to O2. Meanwhile, trioctahedral Fe(II)-Fe(II)-Fe(II) entities were mainly transformed to dioctahedral Fe(II)-Fe(II) entities. When the time of oxygenation was longer than 15 min

Hydroxyl pyridine containing polybenzimidazole membranes for proton exchange membrane fuel cells

DEFF Research Database (Denmark)

Yang, Jingshuai; Xu, Yixin; Zhou, Lu

2013-01-01

A polybenzimidazole variant polymer containing hydroxyl pyridine groups, termed as OHPyPBI, was synthesized from 3,3'-diaminobenzidine tetrahydrochloride and 4-hydroxy-2,6-pyridinedicarboxylic acid. The thermal-oxidative stability of the OHPyPBI polymer was as high as that of poly[2,2'-(m-phenyle...

Peripheral Neuropathy: Symptoms and Signs

Science.gov (United States)

... Utah Research News Make a Difference Symptoms of Peripheral Neuropathy Print This Page Peripheral Neuropathy symptoms usually start ... more slowly over many years. The symptoms of peripheral neuropathy often include: A sensation of wearing an invisible “ ...

Per- and polyfluoroalkyl substances (PFASs) - New endocrine disruptors in polar bears (Ursus maritimus)?

Science.gov (United States)

Pedersen, Kathrine Eggers; Letcher, Robert J; Sonne, Christian; Dietz, Rune; Styrishave, Bjarne

2016-11-01

Per- and polyfluoroalkyl substances (PFASs) are emerging in the Arctic and accumulate in brain tissues of East Greenland (EG) polar bears. In vitro studies have shown that PFASs might possess endocrine disrupting abilities and therefore the present study was conducted to investigate potential PFAS induced alterations in brain steroid concentrations. The concentrations of eleven steroid hormones were determined in eight brain regions from ten EG polar bears. Pregnenolone (PRE), the dominant progestagen, was found in mean concentrations of 5-47ng/g (ww) depending on brain region. PRE showed significantly (pbears. Dehydroepiandrosterone (DHEA) found in mean concentrations 0.67-4.58ng/g (ww) was the androgen found in highest concentrations. Among the estrogens estrone (E1) showed mean concentrations of 0.90-2.21ng/g (ww) and was the most abundant. Remaining steroid hormones were generally present in concentrations below 2ng/g (ww). Steroid levels in brain tissue could not be explained by steroid levels in plasma. There was however a trend towards increasing estrogen levels in plasma resulting in increasing levels of androgens in brain tissue. Correlative analyses showed positive associations between PFASs and 17α-hydroxypregnenolone (OH-PRE) (e.g. perflouroalkyl sulfonates (∑PFSA): ppolar bears. It is, however, not possible to determine whether alterations in brain steroid concentrations arise from interference with de novo steroid synthesis or via disruption of peripheral steroidogenic tissues mainly in gonads and feedback mechanisms. Steroids are important for brain plasticity and gender specific behavior as well as postnatal development and sexually dimorph brain function. The present work indicates an urgent need for a better mechanistic understanding of how PFASs may affect the endocrine system of polar bears and potentially other mammal species. Copyright © 2016 Elsevier Ltd. All rights reserved.

Genomic Evidence of Widespread Admixture from Polar Bears into Brown Bears during the Last Ice Age.

Science.gov (United States)

Cahill, James A; Heintzman, Peter D; Harris, Kelley; Teasdale, Matthew D; Kapp, Joshua; Soares, Andre E R; Stirling, Ian; Bradley, Daniel; Edwards, Ceiridwen J; Graim, Kiley; Kisleika, Aliaksandr A; Malev, Alexander V; Monaghan, Nigel; Green, Richard E; Shapiro, Beth

2018-05-01

Recent genomic analyses have provided substantial evidence for past periods of gene flow from polar bears (Ursus maritimus) into Alaskan brown bears (Ursus arctos), with some analyses suggesting a link between climate change and genomic introgression. However, because it has mainly been possible to sample bears from the present day, the timing, frequency, and evolutionary significance of this admixture remains unknown. Here, we analyze genomic DNA from three additional and geographically distinct brown bear populations, including two that lived temporally close to the peak of the last ice age. We find evidence of admixture in all three populations, suggesting that admixture between these species has been common in their recent evolutionary history. In addition, analyses of ten fossil bears from the now-extinct Irish population indicate that admixture peaked during the last ice age, whereas brown bear and polar bear ranges overlapped. Following this peak, the proportion of polar bear ancestry in Irish brown bears declined rapidly until their extinction. Our results support a model in which ice age climate change created geographically widespread conditions conducive to admixture between polar bears and brown bears, as is again occurring today. We postulate that this model will be informative for many admixing species pairs impacted by climate change. Our results highlight the power of paleogenomics to reveal patterns of evolutionary change that are otherwise masked in contemporary data.

Reaction of single-standard DNA with hydroxyl radical generated by iron(II)-ethylenediaminetetraacetic acid

International Nuclear Information System (INIS)

Prigodich, R.V.; Martin, C.T.

1990-01-01

This study demonstrates that the reaction of Fe(II)-EDTA and hydrogen peroxide with the single-stranded nucleic acids d(pT) 70 and a 29-base sequence containing a mixture of bases results in substantial damage which is not directly detected by gel electrophoresis. Cleavage of the DNA sugar backbone is enhanced significantly after the samples are incubated at 90 degree C in the presence of piperidine. The latter reaction is used in traditional Maxam-Gilbert DNA sequencing to detect base damage, and the current results are consistent with reaction of the hydroxyl radical with the bases in single-stranded DNA (although reaction with sugar may also produce adducts that are uncleaved but labile to cleavage by piperidine). We the authors propose that hydroxyl radicals may react preferentially with the nucleic acid bases in ssDNA and that reaction of the sugars in dsDNA is dominant because the bases are sequestered within the double helix. These results have implications both for the study of single-stranded DNA binding protein binding sites and for the interpretation of experiments using the hydroxyl radical to probe DNA structure or to footprint double-stranded DNA binding protein binding sites

Donating Peripheral Blood Stem Cells

Science.gov (United States)

... Print this page My Cart Donating peripheral blood stem cells Peripheral blood stem cell (PBSC) donation is a nonsurgical procedure to collect ... Donating bone marrow Donor experiences videos Peripheral blood stem cell (PBSC) donation is one of two methods of ...

Scaling laws for radial foil bearings

Science.gov (United States)

Honavara Prasad, Srikanth

The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims

Effect of Hydroxyl Concentration on Chemical Sensitivity of Polyvinyl Alcohol/Carbon-Black Composite Chemiresistors

International Nuclear Information System (INIS)

Hughes, Robert C.; Patel, Sanjay V.; Yelton, W. Graham

1999-01-01

The sensitivity and selectivity of polyvinyl alcohol (PVA) / carbon black composite films have been found to vary depending upon the hydroxylation percentage (''-OH'') of the polymer. These chemiresistors made from PVA films whose polymer backbone is 88% hydroxylated (PVA88) have a high sensitivity to water, while chemiresistors made from PVA75 have a higher sensitivity to methanol. The minor differences in polymer composition result in films with different Hildebrand volubility parameters. The relative responses of several different PVA-based chemiresistors to solvents with different volubility parameters are presented. In addition, polyvinyl acetate (PVAC) films with PVA88 are used in an array to distinguish the responses to methanol-water mixtures

Hydroxylation of nitro-(pentafluorosulfanyl)benzenes via vicarious nucleophilic substitution of hydrogen

Czech Academy of Sciences Publication Activity Database

Beier, Petr; Pastýříková, Tereza

2011-01-01

Roč. 52, č. 34 (2011), s. 4392-4394 ISSN 0040-4039 R&D Projects: GA ČR GAP207/11/0344 Institutional research plan: CEZ:AV0Z40550506 Keywords : pentafluorosulfanyl group * vicarious nucleophilic substitution * hydroxylation Subject RIV: CC - Organic Chemistry Impact factor: 2.683, year: 2011

Bears and pipeline construction in Alaska

Energy Technology Data Exchange (ETDEWEB)

Follmann, E.H.; Hechtel, J.L. (Univ. of Alaska Fairbanks, AK (USA))

1990-06-01

Serious problems were encountered with bears during construction of the 1274-km trans-Alaska oil pipeline between Prudhoe Bay and Valdez. This multi-billion-dollar project traversed both black bear (Ursus americanus Pallas) and grizzly bear (U. arctos L.) habitat throughtout its entire length. Plans for dealing with anticipated problems with bears were often inadequate. Most (71%) problems occurred north of the Yukon River in a previously roadless wilderness where inadequate refuse disposal and widespread animal feeding created dangerous situations. Of the 192 officially reported bear problems associated with the Trans-Alaska Pipeline System (TAPS) (1971-1979), about 65% involved the presence of bears in camps or dumps, 13% the feeding of bears on garbage or handouts, 10% property damage or economic loss, 7% bears under and in buildings, and only 5% charges by bears. Remarkably, no bear-related injuries were reported, suggesting that bears became accustomed to people and did not regard them as a threat. Following construction of the TAPS there have been proposals for pipelines to transport natural gas from Prudhoe Bay to southern and Pacific-rim markets. Based on past experience, some animal control measures were developed during the planning phase for the authorized gas pipeline route in Alaska. Fences installed around 100-person survey camps were found to be effective in deterring bears in two traditionally troublesome areas. 16 refs., 7 figs., 1 tab.

Computational design of rolling bearings

CERN Document Server

Nguyen-Schäfer, Hung

2016-01-01

This book comprehensively presents the computational design of rolling bearings dealing with many interdisciplinary difficult working fields. They encompass elastohydrodynamics (EHD), Hertzian contact theory, oil-film thickness in elastohydrodynamic lubrication (EHL), bearing dynamics, tribology of surface textures, fatigue failure mechanisms, fatigue lifetimes of rolling bearings and lubricating greases, Weibull distribution, rotor balancing, and airborne noises (NVH) in the rolling bearings. Furthermore, the readers are provided with hands-on essential formulas based on the up-to-date DIN ISO norms and helpful examples for computational design of rolling bearings. The topics are intended for undergraduate and graduate students in mechanical and material engineering, research scientists, and practicing engineers who want to understand the interactions between these working fields and to know how to design the rolling bearings for automotive industry and many other industries.

The use of double-decker catcher bearing with face-to-face installed inner layer bearings

Science.gov (United States)

Zhu, Yi-Li; Zheng, Zhong-Qiao

2017-07-01

In active magnetic bearing (AMB) system, the catcher bearings (CB) are indispensable to temporarily support the rotor from directly impacting the stators. In most cases, traditional CB cannot bear the ultra-high speed, vibrations and impacts after a rotor drop event. To address the shortcomings, a double-decker ball bearing (DDBB) with inner two face-to-face angular contact ball bearings are proposed to be used as CB in an AMB system, and the dynamic response of the rotor after a rotor drop event is experimentally analyzed. The results indicate that using a DDBB as a CB helps to reduce the following collision forces after a rotor drop. Larger ball initial contact angles and smaller pre-load force on the inner layer bearings, larger radial clearance of the outer layer bearing and choosing AISI 10AISI 1045 steel which has a larger density for the adapter ring can effectively reduce the maximum impact force after a rotor drop event.

Polar bears, Ursus maritimus

Science.gov (United States)

Rode, Karyn D.; Stirling, Ian

2017-01-01

Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

Acoustic Emission Monitoring of Incipient in Journal Bearings - Part I : Detectability and measurement for bearing damages

International Nuclear Information System (INIS)

Yoon, Dong Jin; Kwon, Oh Yang; Chung, Min Hwa; Kim, Kyung Woong

1994-01-01

In contrast to the machinery using rolling element bearings, systems with journal bearings generally operate in large scale and under severe loading condition such as steam generator turbines and internal combustion engines. Failure of the bearings in these machinery can result in the system breakdown. To avoid the time consuming repair and considerable economic loss, the detection of incipient failure in journal bearings becomes very important. In this experimental approach, acoustic emission monitoring is applied to the detection of incipient failure caused by several types of abnormal operating condition most probable in the journal bearing systems. It has been known that the intervention of foreign materials, insufficient lubrication and misassembly etc. are principal factors to cause bearing failure and distress. The experiment was conducted under such designed conditions as hard particles in the lubrication layer, insufficient lubrication, and metallic contact in the simulated journal bearing system. The results showed that acoustic emission could be an effective tool to detect the incipient failure in journal bearings

Preferential hydroxylation over epoxidation catalysis by a horseradish peroxidase mutant: a cytochrome P450 mimic.

Science.gov (United States)

de Visser, Sam P

2007-10-25

Density functional theory calculations are presented on the catalytic properties of a horseradish peroxidase mutant whereby the axial nitrogen atom is replaced by phosphorus. This mutant has never been studied experimentally and only one theoretical report on this system is known (de Visser, S. P. J. Phys. Chem. B 2006, 110, 20759-20761). Thus, a one-atom substitution in horseradish peroxidase changes the properties of the catalytic center of the enzyme to more cytochrome P450-type qualities. In particular, the phosphorus-substituted horseradish peroxidase mutant reacts with substrates via a unique reactivity pattern, whereby alkanes are regioselectively hydroxylated even in the presence of a double bond. Reaction barriers of propene epoxidation and hydroxylation are almost identical to ones observed for a cytochrome P450 catalyst and significantly higher than those obtained for a horseradish peroxidase catalyst. It is shown that the regioselectivity difference is entropy and thermally driven and that the electron-transfer processes that occur during the reaction mechanism follow cytochrome P450-type patterns in the hydroxylation reaction.

Migration and clinical outcome of mobile-bearing versus fixed-bearing single-radius total knee arthroplasty.

Science.gov (United States)

Van Hamersveld, Koen T; Marang-Van De Mheen, Perla J; Van Der Heide, Huub J L; Van Der Linden-Van Der Zwaag, Henrica M J; Valstar, Edward R; Nelissen, Rob G H H

2018-04-01

Background and purpose - Mobile-bearing total knee prostheses (TKPs) were developed in the 1970s in an attempt to increase function and improve implant longevity. However, modern fixed-bearing designs like the single-radius TKP may provide similar advantages. We compared tibial component migration measured with radiostereometric analysis (RSA) and clinical outcome of otherwise similarly designed cemented fixed-bearing and mobile-bearing single-radius TKPs. Patients and methods - RSA measurements and clinical scores were assessed in 46 randomized patients at baseline, 6 months, 1 year, and annually thereafter up to 6 years postoperatively. A linear mixed-effects model was used to analyze the repeated measurements. Results - Both groups showed comparable migration (p = 0.3), with a mean migration at 6-year follow-up of 0.90 mm (95% CI 0.49-1.41) for the fixed-bearing group compared with 1.22 mm (95% CI 0.75-1.80) for the mobile-bearing group. Clinical outcomes were similar between groups. 1 fixed-bearing knee was revised for aseptic loosening after 6 years and 2 knees (1 in each group) were revised for late infection. 2 knees (1 in each group) were suspected for loosening due to excessive migration. Another mobile-bearing knee was revised after an insert dislocation due to failure of the locking mechanism 6 weeks postoperatively, after which study inclusion was preliminary terminated. Interpretation - Fixed-bearing and mobile-bearing single-radius TKPs showed similar migration. The latter may, however, expose patients to more complex surgical techniques and risks such as insert dislocations inherent to this rotating-platform design.

Mating-related behaviour of grizzly bears inhabiting marginal habitat at the periphery of their North American range.

Science.gov (United States)

Edwards, Mark A; Derocher, Andrew E

2015-02-01

In comparison to core populations, peripheral populations have low density and recruitment, and are subject to different selective pressures, such as environmental conditions, food type and availability, predation, disease, etc., which may result in behavioural modifications to mating. We test the roam-to-mate hypothesis for a peripheral population of grizzly bears (Ursus arctos) at the northern extent of their North American range, in Canada's Arctic. If bears are roaming-to-mate, we predicted greater range size and daily displacement, and more linear movements for receptive animals during the mating period compared to post-mating. In contrast to our predictions, we found that in general range size and displacement increased from mating to post-mating regardless of reproductive status. When considered across both periods, females with cubs-of-the-year had smaller range use metrics than other reproductive groups, which we attribute to a counter-strategy against sexually selected infanticide and the reduced mobility of cubs. Linearity of movements remained near zero during both periods across all groups, suggesting tortuous movements more characteristic of foraging than of mate-searching. We suggest that for this population, finding quality habitat takes precedence over mate-searching in this marginal Arctic landscape. Alternatively, a more monogamous mating system and sequestering behaviour may have obscured movement differences between the two periods. The behavioural differences in mating that we observed from what is typical of core populations may reflect local adaptation to marginal conditions and could benefit the species in the face of ongoing environmental change. Copyright © 2014 Elsevier B.V. All rights reserved.

Biological production of hydroxylated aromatics : Optimization strategies for Pseudomonas putida S12

NARCIS (Netherlands)

Verhoef, A.

2010-01-01

To replace environmentally unfriendly petrochemical production processes, the demand for bio-based production of organic chemicals is increasing. This thesis focuses on the biological production of hydroxylated aromatics from renewable substrates by engineered P. putida S12 including several cases

The possible role of hydroxylation in the detoxification of atrazine in mature vetiver (Chrysopogon zizanioides Nash) grown in hydroponics.

Science.gov (United States)

Marcacci, Sylvie; Raventon, Muriel; Ravanel, Patrick; Schwitzguébel, Jean-Paul

2005-01-01

The resistance mechanism of vetiver (Chrysopogon zizanioides) to atrazine was investigated to evaluate its potential for phytoremediation of environment contaminated with the herbicide. Plants known to metabolise atrazine rely on hydroxylation mediated by benzoxazinones, conjugation catalyzed by glutathione-S-transferases and dealkylation probably mediated by cytochromes P450. All three possibilities were explored in mature vetiver grown in hydroponics during this research project. Here we report on the chemical role of benzoxazinones in the transformation of atrazine. Fresh vetiver roots and leaves were cut to extract and study their content in benzoxazinones known to hydroxylate atrazine, such as 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA), 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) and their mono- and di-glucosylated forms. Identification of benzoxazinones was performed by thin layer chromatography (TLC) and comparison of retention factors (Rf) and UV spectra with standards: although some products exhibited the same Rf as standards, UV spectra were different. Furthermore, in vitro hydroxylation of atrazine could not be detected in the presence of vetiver extracts. Finally, vetiver organs exposed to [14C]-atrazine did not produce any significant amount of hydroxylated products, such as hydroxyatrazine (HATR), hydroxy-deethylatrazine (HDEA), and hydroxy-deisopropylatrazine (HDIA). Altogether, these metabolic features suggest that hydroxylation was not a major metabolic pathway of atrazine in vetiver.

Nanocomposites of ferroelectric polymers with surface-hydroxylated BaTiO 3 nanoparticles for energy storage applications

KAUST Repository

Almadhoun, Mahmoud Nassar Mahmoud

2012-01-01

A facile surface hydroxylation treatment using hydrogen peroxide to modify the surface of BaTiO 3 nanofillers dispersed in a ferroelectric copolymer host has been investigated. We demonstrate that the surface functionalization of the BaTiO 3 nanofillers (<100 nm) with hydroxyl groups results in as much as two orders of magnitude reduction in the leakage current of nanocomposite thin-film capacitors. This reduction is observed concurrently with the enhancement of the effective permittivity and breakdown strength of the thin-film nanocomposites. Surface modified BaTiO 3 particles display better dispersion within the polymer matrix, resulting in enhanced relative permittivity and reduced dielectric loss. The dielectric behavior of the nanocomposite films containing up to 30 vol.% BaTiO 3 agreed well with the Bruggeman model. These results demonstrate the potential of facile surface hydroxylation of nanoparticles towards the fabrication of higher energy-density nanocomposites. © 2012 The Royal Society of Chemistry.

Tumors of peripheral nerves

International Nuclear Information System (INIS)

Ho, Michael; Lutz, Amelie M.

2017-01-01

Differentiation between malignant and benign tumors of peripheral nerves in the early stages is challenging; however, due to the unfavorable prognosis of malignant tumors early identification is required. To show the possibilities for detection, differential diagnosis and clinical management of peripheral nerve tumors by imaging appearance in magnetic resonance (MR) neurography. Review of current literature available in PubMed and MEDLINE, supplemented by the authors' own observations in clinical practice. Although not pathognomonic, several imaging features have been reported for a differentiation between distinct peripheral nerve tumors. The use of MR neurography enables detection and initial differential diagnosis in tumors of peripheral nerves. Furthermore, it plays an important role in clinical follow-up, targeted biopsy and surgical planning. (orig.) [de

Peripheral dentinogenic ghost cell tumor

Directory of Open Access Journals (Sweden)

Sushant S Kamat

2013-01-01

Full Text Available Dentinogenic ghost cell tumors (DGCT are uncommon lesions mainly with rare peripheral types. This report presents a case of peripheral DGCT on the left side of the mandibular alveolar ridge of a heavy smoker, a 68-year-old man, with main presenting feature as a mild pain. Submandibular lymphadenopathy and radiological "saucerization" were evident. Differential diagnosis included fibroma, neurofibroma, peripheral ameloblastoma, peripheral odontogenic fibroma, and peripheral giant cell granuloma. Histologically, ameloblastoma-like epithelial elements were seen in association with grouped ghost cells. Proliferating polyhedral cells and stellate reticulum-like cells with various densities were spread over a wide range of the field. The lesion was curetted and after 2 years of follow up, it did not recur.

Hydroxyl radical induced transformation of phenylurea herbicides: A theoretical study

International Nuclear Information System (INIS)

Mile, Viktória; Harsányi, Ildikó; Kovács, Krisztina; Földes, Tamás; Takács, Erzsébet; Wojnárovits, László

2017-01-01

Aromatic ring hydroxylation reactions occurring during radiolysis of aqueous solutions are studied on the example of phenylurea herbicides by Density Functional Theory calculations. The effect of the aqueous media is taken into account by using the Solvation Model Based on Density model. Hydroxyl radical adds to the ring because the activation free energies (0.4–47.2 kJ mol −1 ) are low and also the Gibbs free energies have high negative values ((−27.4) to (−5.9) kJ mol −1 ). According to the calculations in most of cases the ortho- and para-addition is preferred in agreement with the experimental results. In these reactions hydroxycyclohexadienyl type radicals form. In a second type reaction, when loss of chlorine atom takes place, OH/Cl substitution occurs without cyclohexadienyl type intermediate. - Highlights: • Attack of • OH to aniline, phenol, fenuron, monuron, diuron was studied by DFT. • Ortho-para directing is suggested with –NH 2 , –OH and –NHCON(CH 3 ) 2 groups. • • OH addition to the ring gives hydroxycyclohexadienyl radical. • Attack at C-Cl leads to • OH/Cl substitution without cyclohexadienyl intermediate.

Hydroxylated ceramic waste forms and the absurdity of leach tests

Energy Technology Data Exchange (ETDEWEB)

Roy, R; Odoj, R; Merz, E [eds.

1981-06-01

The repository pressure and temperature conditions during the thermal period projected in US repositories have been drastically lowered in the last year or two to new values of say 175 +- 50/sup 0/K. Using the argument that the evidence from natural models indicates the most stable mineral (= ceramic) hosts for radionuclides, one finds that under these new repository conditions such crystalline assemblages would be micas, clays, zeolites and other hydrated minerals, plus the tetravalent anhydrous oxide families. A waste form consisting of specific hydroxylated candidate phases can be made via a simple in-can technology (demonstrated by Oak Ridge) by reacting liquid wastes with precursor gels or phyllo or tektosilicates at <200/sup 0/C under modest pressure within the final disposal canister. The data on the rate of reaction of typical oxide materials to yield hydroxylated phases under these conditions show that the typical leach test (at 25 to 100/sup 0/C in deionized water) does not provide a simulation of the reactions which will occur. Hence such tests are not only totally meaningless with respect to qualifying a waste form for its role in a repository, they can be downright misleading.

Hydroxylated ceramic waste forms and the absurdity of 'leach tests'

Energy Technology Data Exchange (ETDEWEB)

Roy, R; Odoj, R; Merz, E [eds.

1981-06-01

The repository pressure and temperature conditions during the thermal period projected in U.S. repositories have been drastically lowered in the last year or two to new values of say 175 +- 50 K. Using the argument that the evidence from natural models indicates the most stable mineral (= ceramic) hosts for radionuclides, one finds that under these new repository conditions such crystalline assemblages would be micas, clays, zeolites, and other hydrated minerals, plus the tetravalent anhydrous oxide families. A waste form consisting of specific hydroxylated candidate phase can be made via a simple in-can technology (demonstrated by Oak Ridge) by reacting liquid wastes with precursor gels or phyllo or tektosilicates at <200/sup 0/C under modest pressure within the final disposal canister. The data on the rate of reaction of typical oxide materials to yield hydroxylated phases under these conditions show that the typical leach test (at 25-100/sup 0/C in deionized water) does not provide a simulation of the reactions which will occur. Hence such tests are not only totally meaningless with respect to qualifying a waste form for its role in a repository, they can be downright misleading.

Biocatalytic hydroxylation of n-butane with in situ cofactor regeneration at low temperature and under normal pressure

Directory of Open Access Journals (Sweden)

Svenja Staudt

2012-02-01

Full Text Available The hydroxylation of n-alkanes, which proceeds in the presence of a P450-monooxygenase advantageously at temperatures significantly below room temperature, is described. In addition, an enzymatic hydroxylation of the “liquid gas” n-butane with in situ cofactor regeneration, which does not require high-pressure conditions, was developed. The resulting 2-butanol was obtained as the only regioisomer, at a product concentration of 0.16 g/L.

Ancient DNA reveals differences in behaviour and sociality between brown bears and extinct cave bears.

Science.gov (United States)

Fortes, Gloria G; Grandal-d'Anglade, Aurora; Kolbe, Ben; Fernandes, Daniel; Meleg, Ioana N; García-Vázquez, Ana; Pinto-Llona, Ana C; Constantin, Silviu; de Torres, Trino J; Ortiz, Jose E; Frischauf, Christine; Rabeder, Gernot; Hofreiter, Michael; Barlow, Axel

2016-10-01

Ancient DNA studies have revolutionized the study of extinct species and populations, providing insights on phylogeny, phylogeography, admixture and demographic history. However, inferences on behaviour and sociality have been far less frequent. Here, we investigate the complete mitochondrial genomes of extinct Late Pleistocene cave bears and middle Holocene brown bears that each inhabited multiple geographically proximate caves in northern Spain. In cave bears, we find that, although most caves were occupied simultaneously, each cave almost exclusively contains a unique lineage of closely related haplotypes. This remarkable pattern suggests extreme fidelity to their birth site in cave bears, best described as homing behaviour, and that cave bears formed stable maternal social groups at least for hibernation. In contrast, brown bears do not show any strong association of mitochondrial lineage and cave, suggesting that these two closely related species differed in aspects of their behaviour and sociality. This difference is likely to have contributed to cave bear extinction, which occurred at a time in which competition for caves between bears and humans was likely intense and the ability to rapidly colonize new hibernation sites would have been crucial for the survival of a species so dependent on caves for hibernation as cave bears. Our study demonstrates the potential of ancient DNA to uncover patterns of behaviour and sociality in ancient species and populations, even those that went extinct many tens of thousands of years ago. © 2016 John Wiley & Sons Ltd.

Non-contacting "snubber bearing" for passive magnetic bearing systems

Science.gov (United States)

Post, Richard F

2017-08-22

A new non-contacting magnetic "snubber" bearing is provided for application to rotating systems such as vehicular electromechanical battery systems subject to frequent accelerations. The design is such that in the equilibrium position the drag force of the snubber is very small (milliwatts). However in a typical case, if the rotor is displaced by as little as 2 millimeters a large restoring force is generated without any physical contact between the stationary and rotating parts of the snubber bearing.

Serum Hydroxyl Radical Scavenging Capacity as Quantified with Iron-Free Hydroxyl Radical Source

Science.gov (United States)

Endo, Nobuyuki; Oowada, Shigeru; Sueishi, Yoshimi; Shimmei, Masashi; Makino, Keisuke; Fujii, Hirotada; Kotake, Yashige

2009-01-01

We have developed a simple ESR spin trapping based method for hydroxyl (OH) radical scavenging-capacity determination, using iron-free OH radical source. Instead of the widely used Fenton reaction, a short (typically 5 seconds) in situ UV-photolysis of a dilute hydrogen peroxide aqueous solution was employed to generate reproducible amounts of OH radicals. ESR spin trapping was applied to quantify OH radicals; the decrease in the OH radical level due to the specimen’s scavenging activity was converted into the OH radical scavenging capacity (rate). The validity of the method was confirmed in pure antioxidants, and the agreement with the previous data was satisfactory. In the second half of this work, the new method was applied to the sera of chronic renal failure (CRF) patients. We show for the first time that after hemodialysis, OH radical scavenging capacity of the CRF serum was restored to the level of healthy control. This method is simple and rapid, and the low concentration hydrogen peroxide is the only chemical added to the system, that could eliminate the complexity of iron-involved Fenton reactions or the use of the pulse-radiolysis system. PMID:19794928

Journal and Wave Bearing Impedance Calculation Software

Science.gov (United States)

Hanford, Amanda; Campbell, Robert

2012-01-01

The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

Beauty and cuteness in peripheral vision

Science.gov (United States)

Kuraguchi, Kana; Ashida, Hiroshi

2015-01-01

Guo et al. (2011) showed that attractiveness was detectable in peripheral vision. Since there are different types of attractiveness (Rhodes, 2006), we investigated how beauty and cuteness are detected in peripheral vision with a brief presentation. Participants (n = 45) observed two Japanese female faces for 100 ms, then were asked to respond which face was more beautiful (or cuter). The results indicated that both beauty and cuteness were detectable in peripheral vision, but not in the same manner. Discrimination rates for judging beauty were invariant in peripheral and central vision, while discrimination rates for judging cuteness declined in peripheral vision as compared with central vision. This was not explained by lower resolution in peripheral vision. In addition, for male participants, it was more difficult to judge cuteness than beauty in peripheral vision, thus suggesting that gender differences can have a certain effect when judging cuteness. Therefore, central vision might be suitable for judging cuteness while judging beauty might not be affected by either central or peripheral vision. This might be related with the functional difference between beauty and cuteness. PMID:25999883

Bears, Big and Little. Young Discovery Library Series.

Science.gov (United States)

Pfeffer, Pierre

This book is written for children 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes: (1) the eight species of bears, including black bear, brown bear, grizzly bear, spectacled bear, sun bear, sloth bear, polar bear, and giant panda; (2) geographical habitats of bears; (3)…

Bearing tester data compilation analysis, and reporting and bearing math modeling

Science.gov (United States)

Cody, J. C.

1986-01-01

Integration of heat transfer coefficients, modified to account for local vapor quality, into the 45 mm bearing model has been completed. The model has been evaluated with two flow rates and subcooled and saturated coolant. The evaluation showed that by increasing the flow from 3.6 to 7.0 lbs/sec the average ball temperature was decreased by 102 F, using a coolant temperature of -230 F. The average ball temperature was decreased by 63 F by decreasing the inlet coolant temperature from saturated to -230 F at a flow rate of 7.0 lbs/sec. Since other factors such as friction, cage heating, etc., affect bearing temperatures, the above bearing temperature effects should be considered as trends and not absolute values. The two phase heat transfer modification has been installed in the 57 mm bearing model and the effects on bearing temperatures have been evaluated. The average ball temperature was decreased by 60 F by increasing the flow rate from 4.6 to 9.0 lbs/sec for the subcooled case. By decreasing the inlet coolant temperature from saturation to -24 F, the average ball temperature was decreased 57 F for a flow rate of 9.0 lbs/sec. The technique of relating the two phase heat transfer coefficient to local vapor quality will be applied to the tester model and compared with test data.

Evidence for formation of hydroxyl radicals during reperfusion after global cerebral ischaemia in rats using salicylate trapping and microdialysis

DEFF Research Database (Denmark)

Christensen, Thomas; Bruhn, T; Balchen, T

1994-01-01

Systemic administration of salicylate (SA) to rats (100 mg kg-1 i.p. ) was used as an in vivo trap of hydroxyl radicals (.OH). In the brain SA reacts with hydroxyl radicals to form the stable adducts 2, 3- and 2,5 dihydroxybenzoic acid (DHBAs) which can thus be taken as an index of .OH formation...

Fetal exposure to PCBs and their hydroxylated metabolites in a Dutch cohort

NARCIS (Netherlands)

Soechitram, S.D.; Athanasiadou, M.; Hovander, L.; Bergman, A.; Sauer, P. J. J.

2004-01-01

Polychlorinated biphenyls (PCBs) are still the most abundant pollutants in wildlife and humans. Hydroxylated PCB metabolites (OH-PCBs) are known to be formed in humans and wildlife. Studies in animals show that these metabolites cause endocrine-related toxicity. The health effects in humans have not

Structural Mass Spectrometry of Proteins Using Hydroxyl Radical Based Protein Footprinting

OpenAIRE

Wang, Liwen; Chance, Mark R.

2011-01-01

Structural MS is a rapidly growing field with many applications in basic research and pharmaceutical drug development. In this feature article the overall technology is described and several examples of how hydroxyl radical based footprinting MS can be used to map interfaces, evaluate protein structure, and identify ligand dependent conformational changes in proteins are described.

Tribology of alternative bearings.

Science.gov (United States)

Fisher, John; Jin, Zhongmin; Tipper, Joanne; Stone, Martin; Ingham, Eileen

2006-12-01

The tribological performance and biological activity of the wear debris produced has been compared for highly cross-linked polyethylene, ceramic-on-ceramic, metal-on-metal, and modified metal bearings in a series of in vitro studies from a single laboratory. The functional lifetime demand of young and active patients is 10-fold greater than the estimated functional lifetime of traditional polyethylene. There is considerable interest in using larger diameter heads in these high demand patients. Highly cross-linked polyethylene show a four-fold reduction in functional biological activity. Ceramic-on-ceramic bearings have the lowest wear rates and least reactive wear debris. The functional biological activity is 20-fold lower than with highly cross-linked polyethylene. Hence, ceramic-on-ceramic bearings address the tribological lifetime demand of highly active patients. Metal-on-metal bearings have substantially lower wear rates than highly cross-linked polyethylene and wear decreases with head diameter. Bedding in wear is also lower with reduced radial clearance. Differential hardness ceramic-on-metal bearings and the application of ceramic-like coatings reduce metal wear and ion levels.

Journal bearing impedance descriptions for rotordynamic applications

NARCIS (Netherlands)

Childs, D.W.; Moes, H.; Leeuwen, van H.J.

1977-01-01

Bearing impedance vectors are introduced for plain journal bearings which define the bearing reaction force components as a function of the bearing motion. Impedance descriptions are developed directly for the approximate Ocvirk (short) and Sommerfeld (long) bearing solutions. The impedance vector

Diatomite as high performance and environmental friendly catalysts for phenol hydroxylation with H2O2

Directory of Open Access Journals (Sweden)

Yuxin Jia et al

2007-01-01

Full Text Available A series of diatomite catalysts were treated and characterized. For the first time, the resulting materials were used in catalysis for the hydroxylation of phenol with H2O2 and showed very high hydroxylation activity due to the Fe species in the diatomite. The effect of HCl treatment, contents of catalysts and H2O2 were investigated and the active components of diatomite were discussed. The results show that diatomite is the promising candidate for industrial output due to their high catalytic activity, easy physical separation and very low costs.

TOOL ASSEMBLY WITH BI-DIRECTIONAL BEARING

Science.gov (United States)

Longhurst, G.E.

1961-07-11

A two-direction motion bearing which is incorporated in a refueling nuclear fuel element trsnsfer tool assembly is described. A plurality of bi- directional bearing assembliesare fixed equi-distantly about the circumference of the transfer tool assembly to provide the tool assembly with a bearing surface- for both axial and rotational motion. Each bi-directional bearing assembly contains a plurality of circumferentially bulged rollers mounted in a unique arrangement which will provide a bearing surface for rotational movement of the tool assembly within a bore. The bi-direc tional bearing assembly itself is capable of rational motion and thus provides for longitudinal movement of the tool assembly.

Estimating Wear Of Installed Ball Bearings

Science.gov (United States)

Keba, John E.; Mcvey, Scott E.

1993-01-01

Simple inspection and measurement technique makes possible to estimate wear of balls in ball bearing, without removing bearing from shaft on which installed. To perform measurement, one observes bearing cage while turning shaft by hand to obtain integral number of cage rotations and to measure, to nearest 2 degrees, number of shaft rotations producing cage rotations. Ratio between numbers of cages and shaft rotations depends only on internal geometry of bearing and applied load. Changes in turns ratio reflect changes in internal geometry of bearing provided measurements made with similar bearing loads. By assuming all wear occurs on balls, one computes effective value for this wear from change in turns ratio.

Oral coinfection can stress peripheral lymphocyte to inflammatory activity in leprosy

Directory of Open Access Journals (Sweden)

Ana Carolina Fragoso Motta

2013-01-01

Full Text Available INTRODUCTION: This study evaluated the intracellular profile of interleukin-2 (IL-2, interleukin-4 (IL-4, interleukin-10 (IL-10 and interferon-γ (IFN-γ in peripheral blood mononuclear cells (PBMCs from leprosy patients based on oral infections presence to determine whether these coinfections could be associated with pro-inflammatory activity in leprosy. METHODS: Leprosy patients regardless of clinical form and specific leprosy treatment (n=38 were divided into two groups: Group I - leprosy patients with oral infections (n=19, and Group II - leprosy patients without oral infections (n=19. Non-leprosy patients presenting oral infections were assigned to the control Group (n=10. Intracellular IL-2, IL-4, IL-10 and IFN-γ production was evaluated by flow cytometry (FACS before and 7 days after controlling the oral infection in the Group I, before and 7 days after dental prophylaxis in the Group II, and during oral infection process in control Group. RESULTS: Low percentages of CD3+ lymphocytes bearing IL-2, IL-10 and IFN-γ were observed in the Group I and Group II at baseline and 7 days after therapy or prophylaxis compared to controls. Group I showed reduced percentages of IL-4 at baseline and 7 days after therapy compared to controls, or at baseline of Group II, and the Group II showed reduced percentages of CD3+ cells bearing IL-4 compared to control. An increase of the percentages of CD3+cells bearing IL-4 was observed in the Group I after the oral infections treatment. CONCLUSIONS: The occurrence of oral infections favors the intracellular cytokines expression and, probably, the inflammatory reaction operating as a stimulatory signal triggering the leprosy reactions.

Aqueous photochemical degradation of hydroxylated PAHs: Kinetics, pathways, and multivariate effects of main water constituents

Energy Technology Data Exchange (ETDEWEB)

Ge, Linke; Na, Guangshui [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Chen, Chang-Er [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Li, Jun [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); College of Marine Science, Shanghai Ocean University, Shanghai 201306 (China); Ju, Maowei; Wang, Ying; Li, Kai [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Zhang, Peng, E-mail: pzhang@nmemc.org.cn [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China); Yao, Ziwei [Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, Dalian 116023 (China)

2016-03-15

Hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) are contaminants of emerging concern in the aquatic environment, so it is of great significance to understand their environmental transformation and toxicity. This study investigated the aqueous photochemical behavior of four OH-PAHs, 9-Hydroxyfluorene (9-OHFL), 2-Hydroxyfluorene, 9-Hydroxyphenanthrene and 1-Hydroxypyrene, under simulated sunlight irradiation (λ > 290 nm). It was observed that their photodegradation followed the pseudo-first-order kinetics. Based on the determined quantum yields, their calculated solar apparent photodegradation half-lives in surface waters at 45° N latitude ranged from 0.4 min for 9-Hydroxyphenanthrene to 7.5 × 10{sup 3} min for 9-OHFL, indicating that the OH-PAHs would intrinsically photodegrade fast in sunlit surface waters. Furthermore, 9-OHFL as an example was found to undergo direct photolysis, and self-sensitized photooxidation via ·OH rather than {sup 1}O{sub 2} in pure water. The potential photoreactions involved photoinduced hydroxylation, dehydrogenation and isomerization based on product identification by GC–MS/MS. 9-OHFL photodegraded slower in natural waters than in pure water, which was attributed to the integrative effects of the most photoreactive species, such as Fe(III), NO{sub 3}{sup −}, Cl{sup −} and humic acid. The photomodified toxicity was further examined using Vibrio fischeri, and it was found that the toxicity of photolyzed 9-OHFL did not decrease significantly (p > 0.05) either in pure water or in seawater, implying the comparable or higher toxicity of some intermediates. These results are important for assessing the fate and risks of OH-PAHs in surface waters. - Graphical abstract: Aqueous photochemical behavior of 4 hydroxylated PAHs is first reported on revealing the kinetics, mechanisms, toxicity, and multivariate effects of water constituents. - Highlights: • It is first reported on aqueous photochemical behavior of 4 hydroxylated

The impact of stress on tumor growth: peripheral CRF mediates tumor-promoting effects of stress

Directory of Open Access Journals (Sweden)

Stathopoulos Efstathios N

2010-09-01

Full Text Available Abstract Introduction Stress has been shown to be a tumor promoting factor. Both clinical and laboratory studies have shown that chronic stress is associated with tumor growth in several types of cancer. Corticotropin Releasing Factor (CRF is the major hypothalamic mediator of stress, but is also expressed in peripheral tissues. Earlier studies have shown that peripheral CRF affects breast cancer cell proliferation and motility. The aim of the present study was to assess the significance of peripheral CRF on tumor growth as a mediator of the response to stress in vivo. Methods For this purpose we used the 4T1 breast cancer cell line in cell culture and in vivo. Cells were treated with CRF in culture and gene specific arrays were performed to identify genes directly affected by CRF and involved in breast cancer cell growth. To assess the impact of peripheral CRF as a stress mediator in tumor growth, Balb/c mice were orthotopically injected with 4T1 cells in the mammary fat pad to induce breast tumors. Mice were subjected to repetitive immobilization stress as a model of chronic stress. To inhibit the action of CRF, the CRF antagonist antalarmin was injected intraperitoneally. Breast tissue samples were histologically analyzed and assessed for neoangiogenesis. Results Array analysis revealed among other genes that CRF induced the expression of SMAD2 and β-catenin, genes involved in breast cancer cell proliferation and cytoskeletal changes associated with metastasis. Cell transfection and luciferase assays confirmed the role of CRF in WNT- β-catenin signaling. CRF induced 4T1 cell proliferation and augmented the TGF-β action on proliferation confirming its impact on TGFβ/SMAD2 signaling. In addition, CRF promoted actin reorganization and cell migration, suggesting a direct tumor-promoting action. Chronic stress augmented tumor growth in 4T1 breast tumor bearing mice and peripheral administration of the CRF antagonist antalarmin suppressed this

Noise of oil lubricated journal bearings

International Nuclear Information System (INIS)

Rho, Byoung Hoo; Kim, Kyung Woong

2002-01-01

The purpose of the paper is to provide a procedure to calculate the noise of oil lubricated journal bearings. To do this, the nonlinear transient analysis of rotor-bearing system including rotor imbalance is performed. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Furthermore, a transmission theory of plane waves on a boundary of the outer surface of the bearing is used to obtain the sound pressure level of the bearing. Results show that the sound pressure level of the bearing can be increased with the rotational speed of the rotor although the whirl amplitude of the rotor is decreased at high speed. Noise estimating procedures presented in this paper could be an aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

Drug metabolism by cytochrome p450 enzymes: what distinguishes the pathways leading to substrate hydroxylation over desaturation?

Science.gov (United States)

Ji, Li; Faponle, Abayomi S; Quesne, Matthew G; Sainna, Mala A; Zhang, Jing; Franke, Alicja; Kumar, Devesh; van Eldik, Rudi; Liu, Weiping; de Visser, Sam P

2015-06-15

Cytochrome P450 enzymes are highly versatile biological catalysts in our body that react with a broad range of substrates. Key functions in the liver include the metabolism of drugs and xenobiotics. One particular metabolic pathway that is poorly understood relates to the P450 activation of aliphatic groups leading to either hydroxylation or desaturation pathways. A DFT and QM/MM study has been carried out on the factors that determine the regioselectivity of aliphatic hydroxylation over desaturation of compounds by P450 isozymes. The calculations establish multistate reactivity patterns, whereby the product distributions differ on each of the spin-state surfaces; hence spin-selective product formation was found. The electronic and thermochemical factors that determine the bifurcation pathways were analysed and a model that predicts the regioselectivity of aliphatic hydroxylation over desaturation pathways was established from valence bond and molecular orbital theories. Thus, the difference in energy of the OH versus the OC bond formed and the π-conjugation energy determines the degree of desaturation products. In addition, environmental effects of the substrate binding pocket that affect the regioselectivities were identified. These studies imply that bioengineering P450 isozymes for desaturation reactions will have to include modifications in the substrate binding pocket to restrict the hydroxylation rebound reaction. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Grizzly bears (Ursus arctos horribilis) and black bears (Ursus americanus) prevent trabecular bone loss during disuse (hibernation).

Science.gov (United States)

McGee-Lawrence, Meghan E; Wojda, Samantha J; Barlow, Lindsay N; Drummer, Thomas D; Castillo, Alesha B; Kennedy, Oran; Condon, Keith W; Auger, Janene; Black, Hal L; Nelson, O Lynne; Robbins, Charles T; Donahue, Seth W

2009-12-01

Disuse typically causes an imbalance in bone formation and bone resorption, leading to losses of cortical and trabecular bone. In contrast, bears maintain balanced intracortical remodeling and prevent cortical bone loss during disuse (hibernation). Trabecular bone, however, is more detrimentally affected than cortical bone in other animal models of disuse. Here we investigated the effects of hibernation on bone remodeling, architectural properties, and mineral density of grizzly bear (Ursus arctos horribilis) and black bear (Ursus americanus) trabecular bone in several skeletal locations. There were no differences in bone volume fraction or tissue mineral density between hibernating and active bears or between pre- and post-hibernation bears in the ilium, distal femur, or calcaneus. Though indices of cellular activity level (mineral apposition rate, osteoid thickness) decreased, trabecular bone resorption and formation indices remained balanced in hibernating grizzly bears. These data suggest that bears prevent bone loss during disuse by maintaining a balance between bone formation and bone resorption, which consequently preserves bone structure and strength. Further investigation of bone metabolism in hibernating bears may lead to the translation of mechanisms preventing disuse-induced bone loss in bears into novel treatments for osteoporosis.

Hepatic abscess versus peripheral cholangiocarcinoma: Sonographic differentiation

Energy Technology Data Exchange (ETDEWEB)

Chung, Hwan Hoon; Kim, Yun Hwan; Kang, Chang Ho; Chung, Kyoo Byung; Suh, Won Hyuck [Korea University College of Medicine, Seoul (Korea, Republic of); Lee, Chang Hee [Kunkuk University College of Medicine, Chung-Ju Hospital, Chung-Ju (Korea, Republic of)

2000-12-15

To find out the sonographic findings that are useful to differentiate hepatic abscess from peripheral cholangiocarcinoma. Twenty-two hepatic abscesses and 22 peripheral cholangiocarcinomas which had been confirmed histologically were included in this study. Objective points were echo characteristics of the lesion, internal septation, presence of peripheral low echoic rim, demarcation from normal liver(well or poorly defined), posterior enhancement, multiplicity, dilatation of bile duct(obstructive or non-obstructive), intrahepatic duct stone, pleural effusion, and intra-abdominal fluid collection. Echo characteristics of the lesion were classified in-to four types. Type I; Predominantly echogenic with hypoechoic portion, type II; Echogenic without hypoechoic portion, type III; Predominantly hypoechoic with echogenic portion, type IV; Hypoechoic without echogenic portion. 1)Nine abscesses and 2 peripheral cholangiocarcinomas were type I(p=0.037), 2)One abscess and 18 peripheral cholangiocarcinomas were type II(p=0.001), 3)Seven abscesses and none of peripheral cholangiocarcinomas were type III(p=0.001), 4)Five abscesses and 2 peripheral cholangiocarcinomas were type IV(p=0.410). Only 7 abscesses showed internal septations(p=0.013). One abscess and 9 peripheral cholangiocarcinomas showed peripheral hypoechoic halos(p=0.012). Only 9 peripheral cholangiocarcinomas showed obstructive bile duct dilatation (p=0.001). There were no statistically significant differences between abscess and peripheral cholangiocarcinoma on other objective points. Predominantly echogenic with hypoechoic portion, predominantly hypoechoic with echogenic portion, and internal septation are the features suggestive of hepatic abscess, and echogenic without hypoechoic portion, peripheral hypoechoic halo, obstructive bile duct dilatation are suggestive of peripheral cholangiocarcinoma. Therefore these sonographic findings are helpful to differentiate hepatic abscess from peripheral

Prevalence of Trichinella spp. in black bears, grizzly bears, and wolves in the Dehcho Region, Northwest Territories, Canada, including the first report of T. nativa in a grizzly bear from Canada.

Science.gov (United States)

Larter, Nicholas C; Forbes, Lorry B; Elkin, Brett T; Allaire, Danny G

2011-07-01

Samples of muscle from 120 black bears (Ursus americanus), 11 grizzly bears (Ursus arctos), and 27 wolves (Canis lupus) collected in the Dehcho Region of the Northwest Territories from 2001 to 2010 were examined for the presence of Trichinella spp. larvae using a pepsin-HCl digestion assay. Trichinella spp. larvae were found in eight of 11 (73%) grizzly bears, 14 of 27 (52%) wolves, and seven of 120 (5.8%) black bears. The average age of positive grizzly bears, black bears, and wolves was 13.5, 9.9, and approximately 4 yr, respectively. Larvae from 11 wolves, six black bears, and seven grizzly bears were genotyped. Six wolves were infected with T. nativa and five with Trichinella T6, four black bears were infected with T. nativa and two with Trichinella T6, and all seven grizzly bears were infected with Trichinella T6 and one of them had a coinfection with T. nativa. This is the first report of T. nativa in a grizzly bear from Canada. Bears have been linked to trichinellosis outbreaks in humans in Canada, and black bears are a subsistence food source for residents of the Dehcho region. In order to assess food safety risk it is important to monitor the prevalence of Trichinella spp. in both species of bear and their cohabiting mammalian food sources.

Hydrostatic and hybrid bearing design

CERN Document Server

Rowe, W B

1983-01-01

Hydrostatic and Hybrid Bearing Design is a 15-chapter book that focuses on the bearing design and testing. This book first describes the application of hydrostatic bearings, as well as the device pressure, flow, force, power, and temperature. Subsequent chapters discuss the load and flow rate of thrust pads; circuit design, flow control, load, and stiffness; and the basis of the design procedures and selection of tolerances. The specific types of bearings, their design, dynamics, and experimental methods and testing are also shown. This book will be very valuable to students of engineering des

49 CFR 229.69 - Side bearings.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Side bearings. 229.69 Section 229.69....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in...

Formation of 5,6-dihydroxydihydrothymine-type products in DNA by hydroxyl radicals

International Nuclear Information System (INIS)

Remsen, J.F.; Roti, J.L.R.

1977-01-01

The purpose of the study is to determine whether 5,6-dihydroxydihydrothymine type products in purified DNA and in intact cells results from direct or indirect action and, if indirect, which radical species is primarily responsible. It is concluded that hydroxyl radical is primarily responsible. (U.K.)

Electron beam melting of bearing materials

Energy Technology Data Exchange (ETDEWEB)

Goldschmied, G.; Schuler, A. (Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Elektrotechnik); Elsinger, G.; Koroschetz, F. (MIBA Gleitlager AG, Laakirchen (Austria)); Tschegg, E.K. (Technische Univ., Vienna (Austria). Inst. fuer Angewandte und Technische Physik)

1990-06-01

This paper reports on a surface treatment method for the bearing materials AlSn6 which permits the use of this material without the overlay usually required. Microstructural refinement is achieved by means of a surface melting technique using an electron beam with successive rapid solidification. Extremely fine tin precipitates are formed in the melted surface layer which lead to significantly better tribological properties of the bearing material. Tests compared the tribological properties for AlSn6 bearings treated by the surface melting technique with those of untreated bearings. Whereas all untreated bearings failed by seizure after only 2 h of testing, 30% of the tested bearings which had been surface melted survived the entire testing program without damage.

Hydroxyl-substituted ladder polyethers via selective tandem epoxidation/cyclization sequence.

Science.gov (United States)

Czabaniuk, Lara C; Jamison, Timothy F

2015-02-20

A new and highly selective method for the synthesis of hydroxyl-substituted tetrahydropyrans is described. This method utilizes titanium(IV) isopropoxide and diethyl tartrate to perform a diastereoselective epoxidation followed by in situ epoxide activation and highly selective endo-cyclization to form the desired tetrahydropyran ring. The HIJ ring fragment of the marine ladder polyether yessotoxin was synthesized using this two-stage tactic that proceeds with high efficiency and excellent regioselectivity.

Flywheel Challenge: HTS Magnetic Bearing

International Nuclear Information System (INIS)

Werfel, F N; Floegel-Delor, U; Riedel, T; Rothfeld, R; Wippich, D; Goebel, B

2006-01-01

A 200 mm cylindrical engineering prototype high temperature superconducting (HTS) was designed and fabricated. Measurements show that the 17 kg PM rotor can suspend safely 1000 kg in axial direction and 470 kg radially. The rationale for the bearing performance is to stabilize a 400 kg rotor of a new compact 5 kWh/280 kW flywheel energy storage system (COM - FESS). Measurements of the magnetic bearing force, stiffness and drag-torque are presented indicated the successful targeting a milestone in the HTS bearing technology. The influence of the PM configuration and the YBCO temperature on the bearing performance was experimentally studied, providing high-force or high-stiffness behaviour. The axial stiffness 5 kN/mm at 0.5 mm displacement is the highest value of a HTS bearing we know

Catalytic oxidation of 2-aminophenols and ortho hydroxylation of aromatic amines by tyrosinase

International Nuclear Information System (INIS)

Toussaint, O.; Lerch, K.

1987-01-01

The usual substrates of tyrosinase, a copper-containing monooxygenase (EC 1.14.18.1), are monophenols and o-diphenols which are both converted to o-quinones. In this paper, the authors studied the reaction of this enzyme with two new classes of substrates: aromatic amines and o-aminophenols, structural analogues of monophenols and o-diphenols, respectively. They undergo the same catalytic reactions (ortho hydroxylation and oxidation), as documented by product analysis and kinetic studies. In the presence of tyrosinase, arylamines and o-aminophenols are converted to o-quinone imines, which are isolated as quinone anils or phenoxazones. As an example, in the presence of tyrosinase, 2-amino-3-hydroxybenzoic acid (an o-aminophenol) is converted to cinnabarinic acid, a well-known phenoxazone, while p-aminotoluene (an aromatic amine) gives rise to the formation of 5-amino-2-methyl-1,4-benzoquinone 1-(4-methylanil). Kinetic studies using an oxygen electrode show that arylamines and the corresponding monophenols exhibit similar Michaelis constants. In contrast, the reaction rates observed for aromatic amines are relatively slow as compared to monophenols. The enzymatic conversion of arylamines by tryosinase is different from the typical ones: N-oxidation and ring hydroxylation without further oxidation. This difference originates from the regiospecific hydroxylation (ortho position) and subsequent oxidation of the intermediate o-aminophenol to the corresponding o-quinone imine. Finally, the well-know monooxygenase activity of tyrosinase was also confirmed for the aromatic amine p-aminotoluene, with 18 O 2

Eastern slopes grizzly bear project

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-01-01

The cumulative effects of human activities on the grizzly bears in the central Canadian Rockies are not well known. As a result, a project was initiated in 1994 to address the urgent requirement for accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of this study will be used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers are monitoring 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers involved in the project are working with representatives from Husky Oil and Talisman Energy on the sound development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over seven years indicated that the grizzly bears have few and infrequent offspring. Using the information gathered so far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears recover very slowly from high mortality, and also considering that the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The status of the population and habitat of the grizzly bear will be assessed upon the conclusion of the field research phase in 2001. Models will be updated using the data obtained during eight years and will assist in the understanding of complex variables that affect grizzly bears.

New insights into the aquatic photochemistry of fluoroquinolone antibiotics: Direct photodegradation, hydroxyl-radical oxidation, and antibacterial activity changes.

Science.gov (United States)

Ge, Linke; Na, Guangshui; Zhang, Siyu; Li, Kai; Zhang, Peng; Ren, Honglei; Yao, Ziwei

2015-09-15

The ubiquity and photoreactivity of fluoroquinolone antibiotics (FQs) in surface waters urge new insights into their aqueous photochemical behavior. This study concerns the photochemistry of 6 FQs: ciprofloxacin, danofloxacin, levofloxacin, sarafloxacin, difloxacin and enrofloxacin. Methods were developed to calculate their solar direct photodegradation half-lives (td,E) and hydroxyl-radical oxidation half-lives (tOH,E) in sunlit surface waters. The td,E values range from 0.56 min to 28.8 min at 45° N latitude, whereas tOH,E ranges from 3.24h to 33.6h, suggesting that most FQs tend to undergo fast direct photolysis rather than hydroxyl-radical oxidation in surface waters. However, a case study for levofloxacin and sarafloxacin indicated that the hydroxyl-radical oxidation induced risky photochlorination and resulted in multi-degradation pathways, such as piperazinyl hydroxylation and clearage. Changes in the antibacterial activity of FQs caused by photodegradation in various waters were further examined using Escherichia coli, and it was found that the activity evolution depended on primary photodegradation pathways and products. Primary intermediates with intact FQ nuclei retained significant antibacterial activity. These results are important for assessing the fate and risk of FQs in surface waters. Copyright © 2015. Published by Elsevier B.V.

Effects of hydroxylated benzaldehyde derivatives on radiation-induced reactions involving various organic radicals

Science.gov (United States)

Ksendzova, G. A.; Samovich, S. N.; Sorokin, V. L.; Shadyro, O. I.

2018-05-01

In the present paper, the effects of hydroxylated benzaldehyde derivatives and gossypol - the known natural occurring compound - on formation of decomposition products resulting from radiolysis of ethanol and hexane in deaerated and oxygenated solutions were studied. The obtained data enabled the authors to make conclusions about the effects produced by the structure of the compounds under study on their reactivity towards oxygen- and carbon-centered radicals. It has been found that 2,3-dihydroxybenzaldehyde, 4,6-di-tert-butyl-2,3-dihydroxybenzaldehyde and 4,6-di-tert-butyl-3-(1,3-dioxane-2-yl)-1,2-dihydroxybenzene are not inferior in efficiency to butylated hydroxytoluene - the industrial antioxidant - as regards suppression of the radiation-induced oxidation processes occurring in hexane. The derivatives of hydroxylated benzaldehydes were shown to have a significant influence on radiation-induced reactions involving α-hydroxyalkyl radicals.

Conflict bear translocation: investigating population genetics and fate of bear translocation in Dachigam National Park, Jammu and Kashmir, India.

Science.gov (United States)

Mukesh; Sharma, Lalit Kumar; Charoo, Samina Amin; Sathyakumar, Sambandam

2015-01-01

The Asiatic black bear population in Dachigam landscape, Jammu and Kashmir is well recognized as one of the highest density bear populations in India. Increasing incidences of bear-human interactions and the resultant retaliatory killings by locals have become a serious threat to the survivorship of black bears in the Dachigam landscape. The Department of Wildlife Protection in Jammu and Kashmir has been translocating bears involved in conflicts, henceforth 'conflict bears' from different sites in Dachigam landscape to Dachigam National Park as a flagship activity to mitigate conflicts. We undertook this study to investigate the population genetics and the fate of bear translocation in Dachigam National Park. We identified 109 unique genotypes in an area of ca. 650 km2 and observed bear population under panmixia that showed sound genetic variability. Molecular tracking of translocated bears revealed that mostly bears (7 out of 11 bears) returned to their capture sites, possibly due to homing instincts or habituation to the high quality food available in agricultural croplands and orchards, while only four bears remained in Dachigam National Park after translocation. Results indicated that translocation success was most likely to be season dependent as bears translocated during spring and late autumn returned to their capture sites, perhaps due to the scarcity of food inside Dachigam National Park while bears translocated in summer remained in Dachigam National Park due to availability of surplus food resources. Thus, the current management practices of translocating conflict bears, without taking into account spatio-temporal variability of food resources in Dachigam landscape seemed to be ineffective in mitigating conflicts on a long-term basis. However, the study highlighted the importance of molecular tracking of bears to understand their movement patterns and socio-biology in tough terrains like Dachigam landscape.

Conflict bear translocation: investigating population genetics and fate of bear translocation in Dachigam National Park, Jammu and Kashmir, India.

Directory of Open Access Journals (Sweden)

Mukesh

Full Text Available The Asiatic black bear population in Dachigam landscape, Jammu and Kashmir is well recognized as one of the highest density bear populations in India. Increasing incidences of bear-human interactions and the resultant retaliatory killings by locals have become a serious threat to the survivorship of black bears in the Dachigam landscape. The Department of Wildlife Protection in Jammu and Kashmir has been translocating bears involved in conflicts, henceforth 'conflict bears' from different sites in Dachigam landscape to Dachigam National Park as a flagship activity to mitigate conflicts. We undertook this study to investigate the population genetics and the fate of bear translocation in Dachigam National Park. We identified 109 unique genotypes in an area of ca. 650 km2 and observed bear population under panmixia that showed sound genetic variability. Molecular tracking of translocated bears revealed that mostly bears (7 out of 11 bears returned to their capture sites, possibly due to homing instincts or habituation to the high quality food available in agricultural croplands and orchards, while only four bears remained in Dachigam National Park after translocation. Results indicated that translocation success was most likely to be season dependent as bears translocated during spring and late autumn returned to their capture sites, perhaps due to the scarcity of food inside Dachigam National Park while bears translocated in summer remained in Dachigam National Park due to availability of surplus food resources. Thus, the current management practices of translocating conflict bears, without taking into account spatio-temporal variability of food resources in Dachigam landscape seemed to be ineffective in mitigating conflicts on a long-term basis. However, the study highlighted the importance of molecular tracking of bears to understand their movement patterns and socio-biology in tough terrains like Dachigam landscape.

The role of human outdoor recreation in shaping patterns of grizzly bear-black bear co-occurrence

OpenAIRE

Ladle, Andrew; Steenweg, Robin; Shepherd, Brenda; Boyce, Mark S.

2018-01-01

Species' distributions are influenced by a combination of landscape variables and biotic interactions with other species, including people. Grizzly bears and black bears are sympatric, competing omnivores that also share habitats with human recreationists. By adapting models for multi-species occupancy analysis, we analyzed trail camera data from 192 trail camera locations in and around Jasper National Park, Canada to estimate grizzly bear and black bear occurrence and intensity of trail use....

The role of human outdoor recreation in shaping patterns of grizzly bear-black bear co-occurrence

OpenAIRE

Ladle, Andrew; Steenweg, Robin; Shepherd, Brenda; Boyce, Mark S.

2018-01-01

Species’ distributions are influenced by a combination of landscape variables and biotic interactions with other species, including people. Grizzly bears and black bears are sympatric, competing omnivores that also share habitats with human recreationists. By adapting models for multi-species occupancy analysis, we analyzed trail camera data from 192 trail camera locations in and around Jasper National Park, Canada to estimate grizzly bear and black bear occurrence and intensity of trail use....

Load responsive hydrodynamic bearing

Science.gov (United States)

Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

2002-01-01

A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

Diet and Co-ecology of Pleistocene Short-Faced Bears and Brown Bears in Eastern Beringia

Science.gov (United States)

Matheus, Paul E.

1995-11-01

Carbon and nitrogen stable isotope analysis of fossil bone collagen reveals that Pleistocene short-faced bears ( Arctodus simus) of Beringia were highly carnivorous, while contemporaneous brown bears ( Ursus arctos) had highly variable diets that included varying amounts of terrestrial vegetation, salmon, and small amounts of terrestrial meat. A reconsideration of the short-faced bear's highly derived morphology indicates that they foraged as scavengers of widely dispersed large mammal carcasses and were simultaneously designed both for highly efficient locomotion and for intimidating other large carnivores. This allowed Arctodus to forage economically over a large home range and seek out, procure, and defend carcasses from other large carnivores. The isotope data and this reconstruction of Arctodus' foraging behavior refute the hypothesis that competition from brown bears was a significant factor in the extinction of short-faced bears.

Bearing Change to Metal-On-Polyethylene for Ceramic Bearing Fracture in Total Hip Arthroplasty; Does It Work?

Science.gov (United States)

Lee, Soong Joon; Kwak, Hong Suk; Yoo, Jeong Joon; Kim, Hee Joong

2016-01-01

We evaluated the short-term to midterm results of reoperation with bearing change to metal-on-polyethylene (MoP) after ceramic bearing fracture in ceramic-on-ceramic total hip arthroplasty. Nine third-generation ceramic bearing fractures (6 heads and 3 liners) were treated with bearing change to MoP. Mean age at reoperation was 52.7 years. Mean follow-up was 4.3 years. During follow-up, 2 of 3 liner-fractured hips and 1 of 6 head-fractured hips showed radiologic signs of metallosis and elevated serum chromium levels. Re-reoperation with bearing rechange to a ceramic head was performed for the hips with metallosis. One liner-fractured hip had periprosthetic joint infection. Dislocation occurred in 3 hips. From our experience, bearing change to MoP is not a recommended treatment option for ceramic bearing fracture in total hip arthroplasty. Copyright © 2016 Elsevier Inc. All rights reserved.

Hydroxyl tagging velocimetry in a supersonic flow over a cavity

International Nuclear Information System (INIS)

Pitz, Robert W.; Lahr, Michael D.; Douglas, Zachary W.; Wehrmeyer, Joseph A.; Hu Shengteng; Carter, Campbell D.; Hsu, Kuang-Yu; Lum, Chee; Koochesfahani, Manoochehr M.

2005-01-01

Hydroxyl tagging velocimetry (HTV) measurements of velocity were made in a Mach 2 (M 2) flow with a wall cavity. In the HTV method, ArF excimer laser (193 nm) beams pass through a humid gas and dissociate H2O into H + OH to form a tagging grid of OH molecules. In this study, a 7x7 grid of hydroxyl (OH) molecules is tracked by planar laser-induced fluorescence. The grid motion over a fixed time delay yields about 50 velocity vectors of the two-dimensional flow in the plane of the laser sheets. Velocity precision is limited by the error in finding the crossing location of the OH lines written by the excimer tag laser. With a signal-to-noise ratio of about 10 for the OH lines, the determination of the crossing location is expected to be accurate within ±0.1 pixels. Velocity precision within the freestream, where the turbulence is low, is consistent with this error. Instantaneous, single-shot measurements of two-dimensional flow patterns were made in the nonreacting M 2 flow with a wall cavity under low- and high-pressure conditions. The single-shot profiles were analyzed to yield mean and rms velocity profiles in the M 2 nonreacting flow

Seismic isolation rubber bearings for nuclear facilities

International Nuclear Information System (INIS)

Fujita, Takafumi

1991-01-01

This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial-stress-shear-strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of FBR plants. It also discusses the protection method against aging and the quality control which are important for implementation. (orig./HP)

Seismic isolation rubber bearings for nuclear facilities

International Nuclear Information System (INIS)

Fujita, Takafumi

1989-01-01

This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial stress-shear strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of fast breeder reactor (FBR) plants. The paper also discusses the protection method against aging and the quality control which are important for implementation

Space Station alpha joint bearing

Science.gov (United States)

Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

1987-01-01

Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

Reduced Bearing Excursion After Mobile-Bearing Unicompartmental Knee Arthroplasty is Associated With Poor Functional Outcomes.

Science.gov (United States)

Wahal, Naman; Gaba, Sahil; Malhotra, Rajesh; Kumar, Vijay; Pegg, Elise C; Pandit, Hemant

2018-02-01

A small proportion of patients with mobile unicompartmental knee arthroplasty (UKA) report poor functional outcomes in spite of optimal component alignment on postoperative radiographs. The purpose of this study is to assess whether there is a correlation between functional outcome and knee kinematics. From a cohort of consecutive cases of 150 Oxford medial UKA, patients with fair/poor functional outcome at 1-year postsurgery (Oxford Knee Score [OKS] bearing position with knee flexion angle. Mean OKS in the fair/poor group was 29.9 and the mean OKS in the good/excellent group was 41.1. The tibial slope, time taken to complete the exercises, and patellar tendon angle trend over the flexion range were similar in both the groups; however, bearing position and the extent of bearing excursion differed significantly. The total bearing excursion in the OKS bearing was positioned 1.7 mm more posterior on the tibia in the OKS bearing excursion and positioning, are associated with worse functional outcomes after mobile UKA. Copyright © 2017 Elsevier Inc. All rights reserved.

Peripheral visual performance enhancement by neurofeedback training.

Science.gov (United States)

Nan, Wenya; Wan, Feng; Lou, Chin Ian; Vai, Mang I; Rosa, Agostinho

2013-12-01

Peripheral visual performance is an important ability for everyone, and a positive inter-individual correlation is found between the peripheral visual performance and the alpha amplitude during the performance test. This study investigated the effect of alpha neurofeedback training on the peripheral visual performance. A neurofeedback group of 13 subjects finished 20 sessions of alpha enhancement feedback within 20 days. The peripheral visual performance was assessed by a new dynamic peripheral visual test on the first and last training day. The results revealed that the neurofeedback group showed significant enhancement of the peripheral visual performance as well as the relative alpha amplitude during the peripheral visual test. It was not the case in the non-neurofeedback control group, which performed the tests within the same time frame as the neurofeedback group but without any training sessions. These findings suggest that alpha neurofeedback training was effective in improving peripheral visual performance. To the best of our knowledge, this is the first study to show evidence for performance improvement in peripheral vision via alpha neurofeedback training.

Scattering of State-Selected and Oriented Hydroxyl Radicals by Halogen Hydrides and Xenon

NARCIS (Netherlands)

Moise, A.V.

2007-01-01

The interaction of the OH radical with atoms and other molecules is relevant for many physical and chemical processes involved in atmospheric, combustion and interstellar chemistry. Various experimental and theoretical studies have revealed information concerning the interaction of the hydroxyl

Rolling bearing analysis

CERN Document Server

Harris, Tedric A

2001-01-01

One of the most well-known experts in the field brings cutting-edge research to practitioners in the new edition of this important reference. Covers the improved mathematical calculations for rolling bearing endurance developed by the American Society of Mechanical Engineers and the Society of Lubrication and Tribology Engineers. Updated with new material on Condition-Based Maintenance, new testing methods, and new bearing materials.

Elucidation of the substitution pattern of 9,10-anthraquinones through the chemical shifts of peri-hydroxyl protons

DEFF Research Database (Denmark)

Schripsema, Jan; Danigno, Denise

1996-01-01

In 9,10-anthraquinones the chemical shift of a peri-hydroxyl proton is affected by the substituents in the other benzenoid ring. These effects are additive. They are useful for the determination of substitution patterns and have been used to revise the structures of six previously reported...... anthraquinones containing methoxyl, hydroxyl, methylenedioxy and beta-methyl substituents. Because the chemical shifts of the other protons are hardly affected by substitutions in the other ring, the characteristic chemical shifts for a wide variety of substitution patterns could be derived....

The surgery of peripheral nerves (including tumors)

DEFF Research Database (Denmark)

Fugleholm, Kåre

2013-01-01

Surgical pathology of the peripheral nervous system includes traumatic injury, entrapment syndromes, and tumors. The recent significant advances in the understanding of the pathophysiology and cellular biology of peripheral nerve degeneration and regeneration has yet to be translated into improved...... surgical techniques and better outcome after peripheral nerve injury. Decision making in peripheral nerve surgery continues to be a complex challenge, where the mechanism of injury, repeated clinical evaluation, neuroradiological and neurophysiological examination, and detailed knowledge of the peripheral...... nervous system response to injury are prerequisite to obtain the best possible outcome. Surgery continues to be the primary treatment modality for peripheral nerve tumors and advances in adjuvant oncological treatment has improved outcome after malignant peripheral nerve tumors. The present chapter...

Renewable Modified Cellulose Bearing Chelating Schiff Base for Adsorptive Removal of Heavy Metal Ions and Antibacterial Action.

Science.gov (United States)

Saravanan, R; Ravikumar, L

2017-07-01

  A novel approach toward chemically modified cellulose bearing active chelating Schiff base with hydroxyl group (Cell-Hy) was synthesized. The modified cellulose was examined for its heavy metal ion uptake potential from aqueous solution. The chemical and structural features of the adsorbent were characterized by Fourier transform infrared spectroscopy (FT-IR), solid state 13C-NMR, Scanning Electron Microscopy (SEM), and energy dispersive analysis of X-ray (EDAX) observations. The experimental conditions and adsorption parameters, including pH, initial metal ion concentration, adsorbent dosage, temperature, and contact time were optimized for the removal of Cu(II) and Pb(II) ions. Kinetic parameters, equilibrium adsorption capacities, and correlation coefficients for pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were carried out. The data obtained from the adsorption of Cu(II) and Pb(II) onto Cell-Hy were subjected to Langmuir and Freundlich isotherm models. Thermodynamic parameters have also been evaluated. The antibacterial activity of modified cellulose was tested toward specific bacterial species.

Modeling of Hybrid Permanent Magnetic-Gas Bearings

DEFF Research Database (Denmark)

Morosi, Stefano; Santos, Ilmar

2009-01-01

Modern turbomachinery applications require nowadays ever-growing rotational speeds and high degree of reliability. It then becomes natural to focus the attention of the research to contact-free bearings elements. The present alternatives focus on gas lubricated journal bearings or magnetic bearings....... In the present paper, a detailed mathematical modeling of the gas bearing based on the compressible form of the Reynolds equation is presented. Perturbation theory is applied in order to identify the dynamic characteristic of the bearing. Due to the simple design of the magnetic bearings elements - being...... the rotor equilibrium position can be made independent on the rotational speed and applied load; it becomes function of the passive magnetic bearing offset. By adjusting the offset it is possible to significantly influence the dynamic coefficients of the hybrid bearing....

A motor with superconducting magnetic bearings

International Nuclear Information System (INIS)

Gladun, A.; Stoye, P.; Verges, P.; Gawalek, W.; Habisreuther, T.; Goernert, P.

1993-01-01

Superconducting bearings may be one of the most promising near term applications of HTSC. For use at liquid nitrogen temperature and below, they offer the advantage of lower energy consumption and higher reliability. Different bearing configurations have been proposed. But in order to substitute for conventional bearings a further increase in the critical current density of the superconductor and improved bearing concepts are necessary. For this it is necessary to take into account the peculiarities of the interaction between permanent magnets and bulk superconductors. As a contribution to this programme we present the model of a motor with superconducting magnetic bearings. (orig.)

Valve assembly having remotely replaceable bearings

International Nuclear Information System (INIS)

Johnson, E.R.; Tanner, D.E.

1980-01-01

A valve assembly having remotely replaceable bearings is disclosed wherein a valve disc is supported within a flow duct for rotation about a pair of axially aligned bearings, one of which is carried by a spindle received within a diametral bore in the valve disc, and the other of which is carried by a bearing support block releasably mounted on the duct circumferentially of an annular collar on the valve disc coaxial with its diametrical bore. The spindle and bearing support block are adapted for remote removal to facilitate servicing or replacement of the valve disc support bearings

Peripheral Circulatory Features during High-Frequency Jet Ventilation

Directory of Open Access Journals (Sweden)

M. B. Kontorovich

2010-01-01

Full Text Available The paper gives the results of a study of peripheral circulatory features during high-frequency jet ventilation (HFJV. The main specific features of peripheral circulation and oxygen transport during HFJV are formulated on the basis of a study of cardiac output (impedance cardiography, peripheral vascular resistance, peripheral vascular blood filling (photoplethysmogram analysis, adaptive peripheral blood flow reactions (spectral analysis of peripheral vascular pulsation. HFJV gives rise to the peculiar pattern of peripheral hemodynamics and tissue gas exchange, which is characterized by higher oxygen uptake without a decrease in mixed venous blood saturation, with normal extraction coefficient and preserved low peripheral vascular resistance. During HFJV, unlike traditional ventilation, the main peripheral hemodynamic feature is the increased capillary bed blood volume caused by the blood flow involvement of reserve capillaries under control of volume (parasympathetic regulation of adaptive peripheral hemodynamic reactions. Key words: high-frequency jet ventilation, oxygen transport, peripheral hemodynamics.

The Juxtaposition of Ribose Hydroxyl Groups: The Root of Biological Catalysis and the RNA World?

Science.gov (United States)

Bernhardt, Harold S.

2015-06-01

We normally think of enzymes as being proteins; however, the RNA world hypothesis suggests that the earliest biological catalysts may have been composed of RNA. One of the oldest surviving RNA enzymes we are aware of is the peptidyl transferase centre (PTC) of the large ribosomal RNA, which joins amino acids together to form proteins. Recent evidence indicates that the enzymatic activity of the PTC is principally due to ribose 2 '-OHs. Many other reactions catalyzed by RNA and/or in which RNA is a substrate similarly utilize ribose 2 '-OHs, including phosphoryl transfer reactions that involve the cleavage and/or ligation of the ribose-phosphate backbone. It has recently been proposed by Yakhnin (2013) that phosphoryl transfer reactions were important in the prebiotic chemical evolution of RNA, by enabling macromolecules composed of polyols joined by phosphodiester linkages to undergo recombination reactions, with the reaction energy supplied by the phosphodiester bond itself. The almost unique juxtaposition of the ribose 2'-hydroxyl and 3'-oxygen in ribose-containing polymers such as RNA, which gives ribose the ability to catalyze such reactions, may have been an important factor in the selection of ribose as a component of the first biopolymer. In addition, the juxtaposition of hydroxyl groups in free ribose: (i) allows coordination of borate ions, which could have provided significant and preferential stabilization of ribose in a prebiotic environment; and (ii) enhances the rate of permeation by ribose into a variety of lipid membrane systems, possibly favouring its incorporation into early metabolic pathways and an ancestral ribose-phosphate polymer. Somewhat more speculatively, hydrogen bonds formed by juxtaposed ribose hydroxyl groups may have stabilized an ancestral ribose-phosphate polymer against degradation (Bernhardt and Sandwick 2014). I propose that the almost unique juxtaposition of ribose hydroxyl groups constitutes the root of both biological

Anticancer system created by acrolein and hydroxyl radical generated in enzymatic oxidation of spermine and other biochemical reactions.

Science.gov (United States)

Alarcon, R A

2012-10-01

A hypothesis suggesting the existence of a ubiquitous physiological anticancer system created by two highly reactive oxidative stress inducers with anticancer properties, acrolein and hydroxyl radical, is reported in this communication. Both components can originate separately or together in several biochemical interactions, among them, the enzymatic oxidation of the polyamine spermine, which appear to be their main source. The foundations of this hypothesis encompass our initial search for growth-inhibitors or anticancer compounds in biological material leading to the isolation of spermine, a polyamine that became highly cytotoxic through the generation of acrolein, when enzymatically oxidized. Findings complemented with pertinent literature data by other workers and observed anticancer activities by sources capable of producing acrolein and hydroxyl radical. This hypothesis obvious implication: spermine enzymatic oxidations or other biochemical interactions that would co-generate acrolein and hydroxyl radical, the anticancer system components, should be tried as treatments for any given cancer. The biochemical generation of acrolein observed was totally unexpected, since this aldehyde was known; as a very toxic and highly reactive xenobiotic chemical produced in the pyrolysis of fats and other organic material, found as an atmospheric pollutant, in tobacco smoke and car emissions, and mainly used as a pesticide or aquatic herbicide. Numerous studies on acrolein, considered after our work a biological product, as well, followed. In them, acrolein widespread presence, its effects on diverse cellular proteins, such as, growth factors, and its anticancer activities, were additionally reported. Regarding hydroxyl radical, the second component of the proposed anticancer system, and another cytotoxic product in normal cell metabolism, it co-generates with acrolein in several biochemical interactions, occurrences suggesting that these products might jointly fulfill some

Determinants of RNA polymerase alpha subunit for interaction with beta, beta', and sigma subunits: hydroxyl-radical protein footprinting.

OpenAIRE

Heyduk, T; Heyduk, E; Severinov, K; Tang, H; Ebright, R H

1996-01-01

Escherichia coli RNA polymerase (RNAP) alpha subunit serves as the initiator for RNAP assembly, which proceeds according to the pathway 2 alpha-->alpha 2-->alpha 2 beta-->alpha 2 beta beta'-->alpha 2 beta beta' sigma. In this work, we have used hydroxyl-radical protein footprinting to define determinants of alpha for interaction with beta, beta', and sigma. Our results indicate that amino acids 30-75 of alpha are protected from hydroxyl-radical-mediated proteolysis upon interaction with beta ...

Thermodynamic properties of CO2 absorption in hydroxyl ammonium ionic liquids at pressures of (100-1600) kPa

International Nuclear Information System (INIS)

Kurnia, K.A.; Harris, F.; Wilfred, C.D.; Abdul Mutalib, M.I.; Murugesan, T.

2009-01-01

Solubility of CO 2 in six hydroxyl ammonium ionic liquids 2-hydroxyethanaminium acetate [hea], bis(2-hydroxyethyl)ammonium acetate [bheaa], 2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium acetate [hhemea], 2-hydroxyethanaminium lactate [hel], bis(2-hydroxyethyl)ammonium lactate [bheal], 2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium lactate [hhemel] at temperatures (298.15, 313.15, and 328.16) K and pressures ranging from (100 to 1600) kPa was determined. From the experimental solubility data, the Henry's constant of CO 2 for each hydroxyl ammonium ionic liquids was estimated and reported as a function of temperature. Furthermore, enthalpy and entropy of absorption were obtained from estimated Henry's constant. The results showed that the solubility increase with increasing pressure and decrease with increasing temperature and the solubility of CO 2 in these six hydroxyl ammonium ionic liquids was in sequence: [hea] > [bheaa] > [hel] > [bheal] > [hhemel] > [hhemea].

Fatal snake bite in a brown bear (Ursus arctos L.: A case report

Directory of Open Access Journals (Sweden)

Romel Velev

2015-03-01

Full Text Available Poisoning from snake venom in animals is an emergency which requires immediate attention or otherwise, the delayed and inadequate treatment leads to untoward consequences and death. The present paper describes a case of venomous snakebite in a brown bear cub (Ursus arctos L. and its therapeutic management. The brown bear cub of which was found alone on the slopes of a mountain in the southwest part of the country was presented to the peripheral veterinary practice in Ohrid with a history of dullness, disorientation and excessive swelling around the left forepaw. It was diagnosed for snakebite based on the history and physical examination. The hematological parameters showed reduced values of hemoglobin, packed cell volume and increased total leukocyte count. The biochemical values showed elevated levels of alanine aminotransferase and creatinine. After immobilization of the animal, the treatment was conducted with fluids, corticosteroid and broad spectrum antibiotic with careful monitoring. Despite the treatment which was initiated immediately, it was only partially effective, and the animal died one hour after the beginning of its course. Poisonous snakes are common in the mountainous part of Macedonia and, just like humans, wild bears especially their cubs are susceptible to the deadly venom of some species. The severity of the reaction to snake venom and prognosis in animals depends on a number of factors: on the type and species of snake, on how much venom was injected, on the location of the bite, on the age, health and body weight of the animal and crucially, the time interval between the snakebite and the application of the treatment.

Influence of hydroxyl content of binders on rheological properties of cerium-gadolinium oxide (CGO) screen printing inks

DEFF Research Database (Denmark)

Marani, Debora; Gadea, Christophe; Hjelm, Johan

2015-01-01

vinyl resins) were selected and characterized in solution via viscosimetry method. A high degree of hyper-entanglement was observed for ethyl cellulose polymers, whereas a mitigated effect characterized the two vinyl resins. Cerium-gadolinium oxides (CGO)-based inks, prepared using the selected binders......The influence of hydroxyl content of binders on rheological properties of screen printing inks is investigated. The actual amount of hydroxyl groups is correlated to the level of hyper-entanglement that characterizes the binders in solution. Three of the most used binders (ethyl cellulose, and two...

Transient response of two lobe aerodynamic journal bearing

Directory of Open Access Journals (Sweden)

Saurabh Kumar Yadav

2018-03-01

Full Text Available The dynamic behavior of a rotor-dynamic system is greatly affected by the performance of aerodynamic bearing and the performance of bearing is characterized by the stiffness and damping coefficients. In the present work, stiffness and damping coefficients of bearing are computed and the performance of the bearing is greatly changed with the change in bearing air film profile. The effect of lobe offset factors on the transient performance of aerodynamic bearing is presented. Bifurcation and Poincare diagrams of two lobe journal bearing have been presented for different offset factors. A bearing designer can judge the bearing performance based on bifurcation diagrams.

Servo Reduces Friction In Flexure Bearing

Science.gov (United States)

Clingman, W. Dean

1991-01-01

Proposed servocontrol device reduces such resistive torques as stiction, friction, ripple, and cogging in flexure bearing described in LAR-14348, "Flexure Bearing Reduces Startup Friction". Reduces frictional "bump" torque encountered when bearing ball runs into buildup of grease on bearing race. Also used as cable follower to reduce torque caused by cable and hoses when they bend because of motion of bearing. New device includes torquer across ball race. Torquer controlled by servo striving to keep flexure at null, removing torque to outer ring. In effect, device is inner control loop reducing friction, but does not control platforms or any outer-control-loop functions.

Effector/memory CD8+ T cells synergize with co-stimulation competent macrophages to trigger autoimmune peripheral neuropathy.

Science.gov (United States)

Yang, Mu; Shi, Xiang Qun; Peyret, Corentin; Oladiran, Oladayo; Wu, Sonia; Chambon, Julien; Fournier, Sylvie; Zhang, Ji

2018-04-05

Autoimmune peripheral neuropathy (APN) such as Guillain Barre Syndrome (GBS) is a debilitating illness and sometimes life threatening. The molecular and cellular mechanisms remain elusive but exposure to environmental factors including viral/bacterial infection and injury is highly associated with disease incidence. We demonstrated previously that both male and female B7.2 (CD86) transgenic L31 and L31/CD4KO mice develop spontaneous APN. Here we further reveal that CD8 + T cells in these mice exhibit an effector/memory phenotype, which bears a resemblance to the CD8 + T cell response following persistent cytomegalovirus (CMV) infection in humans and mice, whilst CMV has been considered as one of the most relevant pathogens in APN development. These activated, peripheral myelin Ag specific CD8 + T cells are required for the disease initiation. While an injury to a peripheral nerve results in Wallerian degeneration in control littermates, the same injury accelerates the development of APN in other non-injured nerves of L31 mice which have a predisposed inflammatory background consisting of effector/memory CD8 + T (CD8 + T EM ) cells. However, CD8 + T EM cells alone are not sufficient. A certain threshold of B7.2 expression on nerve macrophages is an additional requisite. Our findings reveal that indeed, the synergism between CD8 + T EM cells and co-stimulation competent macrophages is crucial in inducing autoimmune-mediated peripheral neuropathy. The identification of decisive molecular/cellular players connecting environmental triggers and the occurrence of APN provides opportunities to prevent disease onset, reduce relapses and develop new therapeutic strategies. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

The effect of external dynamic loads on the lifetime of rolling element bearings: accurate measurement of the bearing behaviour

International Nuclear Information System (INIS)

Jacobs, W; Boonen, R; Sas, P; Moens, D

2012-01-01

Accurate prediction of the lifetime of rolling element bearings is a crucial step towards a reliable design of many rotating machines. Recent research emphasizes an important influence of external dynamic loads on the lifetime of bearings. However, most lifetime calculations of bearings are based on the classical ISO 281 standard, neglecting this influence. For bearings subjected to highly varying loads, this leads to inaccurate estimations of the lifetime, and therefore excessive safety factors during the design and unexpected failures during operation. This paper presents a novel test rig, developed to analyse the behaviour of rolling element bearings subjected to highly varying loads. Since bearings are very precise machine components, their motion can only be measured in an accurately controlled environment. Otherwise, noise from other components and external influences such as temperature variations will dominate the measurements. The test rig is optimised to perform accurate measurements of the bearing behaviour. Also, the test bearing is fitted in a modular structure, which guarantees precise mounting and allows testing different types and sizes of bearings. Finally, a fully controlled multi-axial static and dynamic load is imposed on the bearing, while its behaviour is monitored with capacitive proximity probes.

Effect of PCB3 and its hydroxylated metabolites on estradiol secretion, cell viability, and caspase-3 activity in porcine small folicles

Energy Technology Data Exchange (ETDEWEB)

Ptak, A.; Gregoraszczuk, E.L. [Lab. of Reproductive Physiology and Toxicology of Domestic Animals, Inst. of Zoology, Jagiellonian Univ., Krakow (Poland); Ludewig, G.; Lehmler, H.J.; Robertson, L.W. [Dept. of Occupational and Environmental Health, Coll. of Public Health, The Univ. of Iowa, Iowa City, IA (United States)

2004-09-15

In general, highly chlorinated PCBs are slowly metabolized and eliminated. Lower chlorinated PCBs on the other hand are hydroxylated in vitro and in vivo. Surprisingly this does not necessarily mean that these hydroxylated PCBs are rapidly excreted, as recent findings of substantial amounts of hydroxylated PCBs in animal and human blood have shown. Therefore it must be assumed that not only the PCBs themselves, but also their metabolites can participate in the toxic effects of PCBs. Indeed, some hydroxylated metabolites of PCBs (OH-PCBs) have significant estrogenic activity through binding to the estrogen receptors. Surprisingly, PCB54 (2,2',6,6'-tetrachlorobiphenyl) has about 10% of the activity of 4-OH-PCB54 in the MCF-7 focus assay, but does not bind to the estrogen receptor, suggesting the possibility of an additional, yet unknown mechanism of estrogenicity. We found that PCBs and their hydroxylated metabolites cause an increase in estrogen secretion from ovarian follicular cells in vitro, with PCB3 < 4-OHPCB3 < 3, 4-OH-PCB3. The most sensitive follicles were those collected during the early stage of their development. In the present study we used this type of follicles to answer the question whether this observed huge stimulatory action of PCB3 and/or its metabolites on estrogen release into the medium is due to the action on cells viability and cell apoptosis.

Hydroxylation of p-substituted phenols by tyrosinase: Further insight into the mechanism of tyrosinase activity

International Nuclear Information System (INIS)

Muñoz-Muñoz, Jose Luis; Berna, Jose; García-Molina, María del Mar; Garcia-Molina, Francisco; Garcia-Ruiz, Pedro Antonio; Varon, Ramon

2012-01-01

Highlights: ► The action the copper complexes and tyrosinase on phenols is equivalent. ► Isotope effect showed that nucleophilic attack to copper atom may be the slower step. ► The value of ρ (Hammett constant) supports an electrophilic aromatic substitution. ► Data obtained in steady state pH 7 conditions support the mechanism of Scheme 1SM. -- Abstract: A study of the monophenolase activity of tyrosinase by measuring the steady state rate with a group of p-substituted monophenols provides the following kinetic information: k cat m and the Michaelis constant, K M m . Analysis of these data taking into account chemical shifts of the carbon atom supporting the hydroxyl group (δ) and σ p + , enables a mechanism to be proposed for the transformation of monophenols into o-diphenols, in which the first step is a nucleophilic attack on the copper atom on the form E ox (attack of the oxygen of the hydroxyl group of C-1 on the copper atom) followed by an electrophilic attack (attack of the hydroperoxide group on the ortho position with respect to the hydroxyl group of the benzene ring, electrophilic aromatic substitution with a reaction constant ρ of −1.75). These steps show the same dependency on the electronic effect of the substituent groups in C-4. Furthermore, a study of a solvent deuterium isotope effect on the oxidation of monophenols by tyrosinase points to an appreciable isotopic effect. In a proton inventory study with a series of p-substituted phenols, the representation of k cat f n /k cat f 0 against n (atom fractions of deuterium), where k cat f n is the catalytic constant for a molar fraction of deuterium (n) and k cat f 0 is the corresponding kinetic parameter in a water solution, was linear for all substrates. These results indicate that only one of the proton transfer processes from the hydroxyl groups involved the catalytic cycle is responsible for the isotope effects. We suggest that this step is the proton transfer from the hydroxyl group

A prototype construction of bearing heater system

International Nuclear Information System (INIS)

Firman Silitonga

2007-01-01

A bearing heater system has been successfully constructed using transformer-like method of 1000 VA power, 220 V primary voltage, and 50 Hz electrical frequency. The bearing heater consists of primary coil 230 turns, U type and bar-type iron core with 36 cm 2 , 9 cm 2 ,and 3 cm 2 cross-section, and electrical isolation. The bearing heater is used to enlarge the diameter of the bearing so that it can be easily fixed on an electric motor shaft during replacement because the heating is conducted by treated the bearing as a secondary coil of a transformer. This bearing heater can be used for bearing with 3 and 6 cm of inner diameter and 12 cm of maximum outside diameter. (author)

Peripherally applied opioids for postoperative pain

DEFF Research Database (Denmark)

Nielsen, B N; Henneberg, S W; Schmiegelow, K

2015-01-01

BACKGROUND: Opioids applied peripherally at the site of surgery may produce postoperative analgesia with few side effects. We performed this systematic review to evaluate the analgesic effect of peripherally applied opioids for acute postoperative pain. METHODS: We searched PubMed (1966 to June...... 2013), Embase (1980 to June 2013), and the Cochrane Central Register of Controlled Trials (The Cochrane Library 2013, Issue 6). Randomized controlled trials investigating the postoperative analgesic effect of peripherally applied opioids vs. systemic opioids or placebo, measured by pain intensity...... difference -5 mm, 95% CI: -7 to -3) for peripherally applied opioids vs. placebo and statistically significant increased time to first analgesic (mean difference 153 min, 95% CI: 41-265). When preoperative inflammation was reported (five studies), peripherally applied opioids significantly improved...

Roller bearing geometry design

Science.gov (United States)

Savage, M.; Pinkston, B. H. W.

1976-01-01

A theory of kinematic stabilization of rolling cylinders is extended and applied to the design of cylindrical roller bearings. The kinematic stabilization mechanism puts a reverse skew into the rolling elements by changing the roller taper. Twelve basic bearing modification designs are identified amd modeled. Four have single transverse convex curvature in their rollers while eight have rollers which have compound transverse curvature made up of a central cylindrical band surrounded by symmetric bands with slope and transverse curvature. The bearing designs are modeled for restoring torque per unit axial displacement, contact stress capacity, and contact area including dynamic loading, misalignment sensitivity and roller proportion. Design programs are available which size the single transverse curvature roller designs for a series of roller slopes and load separations and which design the compound roller bearings for a series of slopes and transverse radii of curvature. The compound rollers are proportioned to have equal contact stresses and minimum size. Design examples are also given.

Gear bearing drive

Science.gov (United States)

Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor); Weinberg, Brian (Inventor)

2011-01-01

A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

Quantum Chemical Study on the Antioxidation Mechanism of Piceatannol and Isorhapontigenin toward Hydroxyl and Hydroperoxyl Radicals.

Directory of Open Access Journals (Sweden)

Yang Lu

Full Text Available A systematic study of the antioxidation mechanisms behind hydroxyl (•OH and hydroperoxyl (•OOH radical scavenging activity of piceatannol (PIC and isorhapontigenin (ISO was carried out using density functional theory (DFT method. Two reaction mechanisms, abstraction (ABS and radical adduct formation (RAF, were discussed. A total of 24 reaction pathways of scavenging •OH and •OOH with PIC and ISO were investigated in the gas phase and solution. The thermodynamic and kinetic properties of all pathways were calculated. Based on these results, we evaluated the antioxidant activity of every active site of PIC and ISO and compared the abilities of PIC and ISO to scavenge radicals. According to our results, PIC and ISO may act as effective •OH and •OOH scavengers in organism. A4-hydroxyl group is a very important active site for PIC and ISO to scavenge radicals. The introducing of -OH or -OCH3 group to the ortho-position of A4-hydroxyl group would increase its antioxidant activity. Meanwhile, the conformational effect was researched, the results suggest that the presence and pattern of intramolecular hydrogen bond (IHB are considerable in determining the antioxidant activity of PIC and ISO.

The Effect of Non-Circular Bearing Shapes in Hydrodynamic Journal Bearings on the Vibration Behavior of Turbocharger Structures

Directory of Open Access Journals (Sweden)

Lukas Bernhauser

2017-03-01

Full Text Available Increasing quality demands of combustion engines require, amongst others, improvements of the engine’s acoustics and all (subcomponents mounted to the latter. A significant impact to the audible tonal noise spectrum results from the vibratory motions of fast-rotating turbocharger rotor systems in multiple hydrodynamic bearings such as floating bearing rings. Particularly, the study of self-excited non-linear vibrations of the rotor-bearing systems is crucial for the understanding, prevention or reduction of the noise and, consequently, for a sustainable engine acoustics development. This work presents an efficient modeling approach for the investigation, optimization, and design improvement of complex turbocharger rotors in hydrodynamic journal bearings, including floating bearing rings with circular and non-circular bearing geometries. The capability of tonal non-synchronous vibration prevention using non-circular bearing shapes is demonstrated with dynamic run-up simulations of the presented model. These findings and the performance of our model are compared and validated with results of a classical Laval/Jeffcott rotor-bearing model and a specific turbocharger model found in the literature. It is shown that the presented simulation method yields fast and accurate results and furthermore, that non-circular bearing shapes are an effective measure to reduce or even prevent self-excited tonal noise.

LIGHT-WEIGHT LOAD-BEARING STRUCTURE

DEFF Research Database (Denmark)

2009-01-01

The invention relates to a light-weight load-bearing structure (1) with optimized compression zone (2), where along one or more compression zones (2) in the structure (1) to be cast a core (3) of strong concrete is provided, which core (3) is surrounded by concrete of less strength (4) compared...... to the core (3) of strong concrete. The invention also relates to a method of casting of light-weight load-bearing structures (1) with optimized compression zone (2) where one or more channels, grooves, ducts, pipes and/or hoses (5) formed in the load-bearing structure (1) serves as moulds for moulding one...... or more cores (3) of strong concrete in the light-weight load-bearing structure (1)....

Uranium-bearing breccia pipes of northwestern Arizona - an overview

International Nuclear Information System (INIS)

Chenoweth, W.L.

1986-01-01

During the 1950s and 1960s, the uranium deposits in breccia pipes of the Grand Canyon region were regarded as geologic curiosities. Today this area is the site of numerous exploration projects for ore-bearing pipes. The classic example of the older mines is the Orphan Lode, a patented claim within Grand Canyon National Park. Between 1956 and 1969, this deposit produced 4.26 million lb U 3 O 8 . Exploration since the mid-1970s has developed numerous new deposits in the Grand Canyon region. The Hack 1, 2, and 3, Pigeon, Kanab North, Canyon, and Pinenut deposits are, or will be, mined. The pipes are circular and originated by dissolution of the Mississippian Redwall Limestone and collapse of the overlying strata. Uraninite ore occurs in both the pipe fill and in association with the peripheral shear zone. The principal host rocks are the Coconino Sandstone, Hermit Shale, and Esplanade Sandstone. Although small (3 to 5 million lb U 3 O 8 ), the high grade (60 to 70% U 3 O 8 ) of the deposits makes the pipes attractive exploration targets

Development and Evaluation of Titanium Spacesuit Bearings

Science.gov (United States)

Rhodes, Richard; Battisti, Brian; Ytuarte, Raymond, Jr.; Schultz, Bradley

2016-01-01

The Z-2 Prototype Planetary Extravehicular Space Suit Assembly is a continuation of NASA's Z-series of spacesuits, designed with the intent of meeting a wide variety of exploration mission objectives, including human exploration of the Martian surface. Incorporating titanium bearings into the Z-series space suit architecture allows us to reduce mass by an estimated 23 lbs per suit system compared to the previously used stainless steel bearing race designs, without compromising suit functionality. There are two obstacles to overcome when using titanium for a bearing race- 1) titanium is flammable when exposed to the oxygen wetted environment inside the space suit and 2) titanium's poor wear properties are often challenging to overcome in tribology applications. In order to evaluate the ignitability of a titanium space suit bearing, a series of tests were conducted at White Sands Test Facility (WSTF) that introduced the bearings to an extreme test profile, with multiple failures imbedded into the test bearings. The testing showed no signs of ignition in the most extreme test cases; however, substantial wear of the bearing races was observed. In order to design a bearing that can last an entire exploration mission (approx. 3 years), design parameters for maximum contact stress need to be identified. To identify these design parameters, bearing test rigs were developed that allow for the quick evaluation of various bearing ball loads, ball diameters, lubricants, and surface treatments. This test data will allow designers to minimize the titanium bearing mass for a specific material and lubricant combination and design around a cycle life requirement for an exploration mission. This paper reviews the current research and testing that has been performed on titanium bearing races to evaluate the use of such materials in an enriched oxygen environment and to optimize the bearing assembly mass and tribological properties to accommodate for the high bearing cycle life for an

Burn-related peripheral neuropathy: A systematic review.

Science.gov (United States)

Tu, Yiji; Lineaweaver, William C; Zheng, Xianyou; Chen, Zenggan; Mullins, Fred; Zhang, Feng

2017-06-01

Peripheral neuropathy is the most frequent disabling neuromuscular complication of burns. However, the insidious and progressive onset of burn neuropathy makes it often undiagnosed or overlooked. In our study, we reviewed the current studies on the burn-related peripheral neuropathy to summarize the morbidity, mechanism, detecting method and management of peripheral neuropathy in burn patients. Of the 1533 burn patients included in our study, 98 cases (6.39%) were presented with peripheral neuropathy. Thermal and electrical burns were the most common etiologies. Surgical procedures, especially nerve decompression, showed good effect on functional recovery of both acute and delayed peripheral neuropathy in burn patients. It is noteworthy that, for early detection and prevention of peripheral neuropathy, electrodiagnostic examinations should be performed on burn patients independent of symptoms. Still, the underlying mechanisms of burn-related peripheral neuropathy remain to be clarified. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

The thermodynamic properties of a new type catcher bearing used in active magnetic bearings system

International Nuclear Information System (INIS)

Jin, Chaowu; Zhu, Yili; Xu, Longxiang; Xu, Yuanping; Zheng, Yantong

2015-01-01

Normally a rotor levitated by active magnetic bearings (AMBs) system would rotate without contacting with any stator component, but the possibility still remains that the supporting force might lose temporarily or permanently, thus requiring the Catcher bearings (CBs) to provide backup protection in case of the failure of AMBs. A new type CB with two separate rolling element bearing series could have the speed distribution between the inner race and intermediate race according to certain ratio, in which the speed of each roller element bearing decreases with the limit speed of the whole CB increasing, offering high capability to sustain its initial rotation speed. Based on the theory of heat transfer, tribology, and rotor dynamics, this paper analyzes the thermal structure of double-decker catcher bearing (DDCB) and single-decker catcher bearing (SDCB), respectively. Through this structure, the thermal resistances and equations of heat transfer can be obtained. Then we calculate the friction heat and temperature distribution in the various CBs upon rotor's dropping on SDCB or DDCB, followed by the discussion on the CBs temperature rise's effects on lubrication conditions and rotor dynamics parameters. Finally various experiments are carried out to measure the temperature rise of different CBs. The results obtained validate the theoretical analysis and also provide main methods to reduce heat generation. Using DDCB is proved to be effective to reduce the temperature rise. - Highlights: • The DDCB is a more suitable catcher bearing for AMBs. • Compared to SDCB, using DDCB, the temperature rise can decrease in the same states. • A lower viscosity of lubricant may induce a lower temperature rise. • The inner raceway temperature of the first layer bearing is the highest. • Reducing the unbalance mass of the rotor is a method to decrease the temperature rise

Herbal Medicine AC591 Prevents Oxaliplatin-Induced Peripheral Neuropathy in Animal Model and Cancer Patients

Directory of Open Access Journals (Sweden)

Xiaolan Cheng

2017-06-01

Full Text Available Oxaliplatin is clinically compelling because of severe peripheral neuropathy. The side effect can result in dosage reductions or even cessation of chemotherapy, and no effective treatments are available. AC591 is a standardized extract of Huangqi Guizhi Wuwu decoction, an herbal formula recorded in “Synopsis of the Golden Chamber” for improving limb numbness and pain. In this study, we investigated whether AC591 could protect against oxaliplatin-induced peripheral neuropathy. To clarify it, a rat model of oxaliplatin-induced peripheral neuropathy was established, and neuroprotective effect of AC591 was studied. Our results showed that pretreatment with AC591 reduced oxaliplatin-induced cold hyperalgesia, mechanical allodynia as well as morphological damage of dorsal root ganglion. Microarray analysis indicated the neuroprotective action of AC591 depended on the modulation of multiple molecular targets and pathways involved in the downregulation of inflammation and immune response. Moreover, AC591 enhanced the antitumor activity of oxaliplatin to some extent in Balb/c mice bearing CT-26 carcinoma cells. The efficacy of AC591 is also investigated in 72 colorectal cancer patients. After four cycles of treatment, the percentage of grades 1–2 neurotoxicity in AC591-treated group (n = 36 was 25%, whereas in the control group the incidence was 55.55% (P < 0.01 (n = 36. No significant differences in the tumor response rate between the two groups were found. These evidences suggested that AC591 can prevent oxaliplatin-induced neuropathy without reducing its antitumor activity, and may be a promising adjuvant to alleviate sensory symptoms in clinical practice.

Noise estimation of oil lubricated journal bearings

International Nuclear Information System (INIS)

Rho, Byoung Hoo; Kim, Kyung Woong

2003-01-01

Noise estimating procedures of oil lubricated journal bearings are presented. Nonlinear analysis of rotor-bearing system including unbalance mass of the rotor is performed in order to obtain acoustical properties of the bearing. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Noise estimating procedures presented in this paper could aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

Individual effects of seasonal changes, visitor density, and concurrent bear behavior on stereotypical behaviors in captive polar bears (Ursus maritimus).

Science.gov (United States)

Kelly, Krista R; Harrison, Michelle L; Size, Daniele D; MacDonald, Suzanne E

2015-01-01

Stereotypical behaviors in captive polar bears (Ursus maritimus) can be detrimental to their welfare. These behaviors can be reduced through enrichment programs but are often not completely eliminated, so identifying potential triggers is important. The present study investigated the influences of seasonal changes, visitor density, and concurrent bear activity on stereotypical behaviors exhibited by 3 captive polar bears at the Toronto Zoo. All bears exhibited these behaviors; however, individual differences were found in duration and form. The male exhibited less stereotypical behavior during spring, and the females exhibited less stereotypical behavior during winter. An increase in visitor density was associated with more stereotypical behavior in 1 female but less stereotypical behavior in the other 2 bears. All bears engaged in more stereotypical behaviors when the other bears were inactive, and 1 female engaged in more stereotypical behaviors when the other bears were out of sight. Further, when conspecifics were active, all bears engaged in less stereotypical behaviors. Given the variability among individual bears, future enrichment programs must be tailored to the needs of individuals to maximize efficacy.

From cation to oxide: hydroxylation and condensation of aqueous complexes

International Nuclear Information System (INIS)

Jolivet, J.P.

1997-01-01

Hydroxylation, condensation and precipitation of metal cations in aqueous solution are briefly reviewed. Hydroxylation of aqueous complexes essentially depends on the format charge (oxidation state), the size and the pH of the medium. It is the step allowing the condensation reaction. Depending on the nature of complexes (aqua-hydroxo, oxo-hydroxo), the. mechanism of condensation is different, olation or ox-olation respectively. The first one leads to poly-cations or hydroxides more or less stable against dehydration. The second one leads to poly-anions or oxides. Oligomeric species (poly-cations, poly-anions) are form from charged monomer complexes while the formation of solid phases requires non-charged precursors. Because of their high lability, charged oligomers are never the precursors of solids phases. The main routes for the formation of solid phases from solution are studied with two important and representative elements, Al and Si. For Al 3+ ions, different methods (base addition in solution, thermo-hydrolysis, hydrothermal synthesis) are discussed in relation to the crystal structure of the solid phase obtained. For silicic species condensing by ox-olation, the role of acid or base catalysis on the morphology of gels is studied. The influence of complexing ligands on the processes and on the characteristics of solids (morphology of particles, basic salts and polymetallic oxides formation) is studied. (author)

Infrared Emission Spectrum of the Hydroxyl Radical: A Novel Experiment in Molecular Spectroscopy.

Science.gov (United States)

Henderson, Giles; And Others

1982-01-01

Describes an experiment in which parameters from an "ab-initio" potential are used to calculate vibrational-rotational energy levels and construct a "stick spectrum" for the overtone emission of the hydroxyl radical. Provides background information on ab-initio spectrum, experimental procedures, and analysis of data. (Author/JN)

49 CFR 229.64 - Plain bearings.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Plain bearings. 229.64 Section 229.64 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....64 Plain bearings. A plain bearing box shall contain visible free oil and may not be cracked to the...

Study on the plasma reaction process of hydroxyl generation by strong electric field ionization discharge

International Nuclear Information System (INIS)

Bai Mindi; Deng Shufang; Bai Xiyao; Zhang Zhitao

2004-01-01

Considering the change in the structure of reaction room, dielectric materials and process technology, authors have specifically studied the plasma reaction process of creating hydroxyl radical OH * and e aq - from ionization of O 2 and H 2 O through a strong electric field discharge. The production volume of hydroxyl radical OH * is up to the project application level, and process technology meets the 12 laws of green chemistry, free from environmental pollution from the source. The authors have emphatically researched on the green method of flue gas desulfurization, which will ionize SO 2 , H 2 O and O 2 in the flue gas to synthesis H 2 SO 4 in molecular level within 0.8 s without absorbent and catalyst. (author)

Hydroxylation of benzene to phenol over magnetic recyclable nanostructured CuFe mixed-oxide catalyst

CSIR Research Space (South Africa)

Makgwane, PR

2015-03-01

Full Text Available A highly active and magnetically recyclable nanostructured copper–iron oxide (CuFe) catalyst has been synthesized for hydroxylation of benzene to phenol under mild reaction conditions. The obtained catalytic results were correlated with the catalyst...

Gold-catalyzed Alkyne Hydroxylation: Synthesis of 2-Substituted Benzo[b]furan Compounds

Institute of Scientific and Technical Information of China (English)

ZHANG Yuan; XIN Zhi-Jun; XUE Ji-Jun; LI Ying

2008-01-01

A strategy concerning the synthesis of 2-substituted benzo[b]furan compounds from o-alkynyl phenols via a gold-catalyzed alkyne hydroxylation is described, which allows the rapid synthesis of various 2-substituted benzo[b]furan derivatives in excellent yields under mild conditions. The o-alkynyl phenol precursors were readily prepared with a Sonogashira coupling reaction.

Ceramic Rail-Race Ball Bearings

Science.gov (United States)

Balzer, Mark A.; Mungas, Greg S.; Peters, Gregory H.

2010-01-01

Non-lubricated ball bearings featuring rail races have been proposed for use in mechanisms that are required to function in the presence of mineral dust particles in very low-pressure, dry environments with extended life. Like a conventional ball bearing, the proposed bearing would include an inner and an outer ring separated by balls in rolling contact with the races. However, unlike a conventional ball bearing, the balls would not roll in semi-circular or gothic arch race grooves in the rings: instead, the races would be shaped to form two or more rails (see figure). During operation, the motion of the balls would push dust particles into the spaces between the rails where the particles could not generate rolling resistance for the balls

Study on the surface hydroxyl group on solid breeding materials by infrared absorption spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Satoru; Taniguchi, Masaki [Tokyo Univ. (Japan). Faculty of Engineering

1996-10-01

Hydroxyl groups on the surface of Li{sub 2}O were studied by using a diffuse reflectance method with Fourier transform infrared absorption spectroscopy at high temperature up to 973K under controlled D{sub 2}O or D{sub 2} partial pressure. It was found that hydroxyl groups could exist on Li{sub 2}O surface up to 973K under Ar atmosphere. Under D{sub 2}O containing atmosphere, only the sharp peak at 2520cm{sup -1} was observed at 973K in the O-D stretching vibration region. Below 973K, multiple peaks due to the surface -OD were observed and they showed different behavior with temperature or atmosphere. Multiple peaks mean that surface is not homogeneous for D{sub 2}O adsorption. Assignment of the observed peaks to the surface bonding structure was also discussed. (author)

Increased hypoxia-inducible factor-1α in striated muscle of tumor-bearing mice.

Science.gov (United States)

Devine, Raymond D; Bicer, Sabahattin; Reiser, Peter J; Wold, Loren E

2017-06-01

Cancer cachexia is a progressive wasting disease resulting in significant effects on the quality of life and high mortality. Most studies on cancer cachexia have focused on skeletal muscle; however, the heart is now recognized as a major site of cachexia-related effects. To elucidate possible mechanisms, a proteomic study was performed on the left ventricles of colon-26 (C26) adenocarcinoma tumor-bearing mice. The results revealed several changes in proteins involved in metabolism. An integrated pathway analysis of the results revealed a common mediator in hypoxia-inducible factor-1α (HIF-1α). Work by other laboratories has shown that extensive metabolic restructuring in the C26 mouse model causes changes in gene expression that may be affected directly by HIF-1α, such as glucose metabolic genes. M-mode echocardiography showed progressive decline in heart function by day 19 , exhibited by significantly decreased ejection fraction and fractional shortening, along with posterior wall thickness. Using Western blot analysis, we confirmed that HIF-1α is significantly upregulated in the heart, whereas there were no changes in its regulatory proteins, prolyl hydroxylase domain-containing protein 2 (PHD2) and von Hippel-Lindau protein (VHL). PHD2 requires both oxygen and iron as cofactors for the hydroxylation of HIF-1α, marking it for ubiquination via VHL and subsequent destruction by the proteasome complex. We examined venous blood gas values in the tumor-bearing mice and found significantly lower oxygen concentration compared with control animals in the third week after tumor inoculation. We also examined select skeletal muscles to determine whether they are similarly affected. In the diaphragm, extensor digitorum longus, and soleus, we found significantly increased HIF-1α in tumor-bearing mice, indicating a hypoxic response, not only in the heart, but also in skeletal muscle. These results indicate that HIF-1α may contribute, in part, to the metabolic changes

Identification of Bearing Failure Using Signal Vibrations

Science.gov (United States)

Yani, Irsyadi; Resti, Yulia; Burlian, Firmansyah

2018-04-01

Vibration analysis can be used to identify damage to mechanical systems such as journal bearings. Identification of failure can be done by observing the resulting vibration spectrum by measuring the vibration signal occurring in a mechanical system Bearing is one of the engine elements commonly used in mechanical systems. The main purpose of this research is to monitor the bearing condition and to identify bearing failure on a mechanical system by observing the resulting vibration. Data collection techniques based on recordings of sound caused by the vibration of the mechanical system were used in this study, then created a database system based bearing failure due to vibration signal recording sounds on a mechanical system The next step is to group the bearing damage by type based on the databases obtained. The results show the percentage of success in identifying bearing damage is 98 %.

Management of brown bears (Ursus arctos) in Europe.

OpenAIRE

Klenzendorf, Sybille A.

1997-01-01

Management of Brown Bears (Ursus arctos) in Europe. Sybille A. Klenzendorf (Abstract) Successful conservation of brown bears (Ursus arctos) in Europe is associated with public acceptance of damages caused by bears. Recent increases in sheep depredation and beehive damage in central Austria resulted in the deaths of two bears there. Since bear numbers are low in most European populations, alternatives to the elimination of problem bears associated with dam...

Conservation of brown bear in the Alps: space use and settlement behavior of reintroduced bears

Science.gov (United States)

Preatoni, Damiano; Mustoni, Andrea; Martinoli, Adriano; Carlini, Eugenio; Chiarenzi, Barbara; Chiozzini, Simonetta; Van Dongen, Stefan; Wauters, Luc A.; Tosi, Guido

2005-11-01

Large carnivores typically need large home ranges containing habitats patches of different quality. Consequently, their conservation requires habitat protection and management at the landscape scale. In some cases, reintroduction might be used to support remnant or restore extinct populations. This is the case for the brown bear ( Ursus arctos) in the Italian Alps. We monitored spacing behavior and settlement of reintroduced brown bears in Adamello-Brenta Natural Park, North-Italy, using radio-tracking. Habitat use, dispersion and survival were studied to evaluate the success of reintroduction and possible conflicts with man. All three males and five of seven females settled in the study area. Most bears roamed widely the first months after release, exploring the new habitat. Patterns of home range overlap between seasons and years revealed that home range use stabilized the year after first hibernation. Home ranges were larger in the mating season (May-July) than in spring or autumn. Home ranges varied between 34 and 1813 km 2 the year after release, but core-areas, where feeding activity was concentrated, were much smaller. Some bears had exclusive core-areas in summer and autumn, but most showed considerable core-area overlap with animals of the same and/or the opposite sex. Bears selected deciduous forests, mixed and conifer forests were used according to availability, and areas with anthropogenic disturbance were avoided. Most bears settled and some reproduced successfully at the release site, causing high initial population growth, suggesting that reintroduction can help to re-establish a brown bear population in the Italian Alps.

Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C-H Amination and Hydroxylation.

Science.gov (United States)

Zheng, Yi-Wen; Chen, Bin; Ye, Pan; Feng, Ke; Wang, Wenguang; Meng, Qing-Yuan; Wu, Li-Zhu; Tung, Chen-Ho

2016-08-17

We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobalt catalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually mild conditions in excellent yields and selectivities.

Intraoperative Ultrasound for Peripheral Nerve Applications.

Science.gov (United States)

Willsey, Matthew; Wilson, Thomas J; Henning, Phillip Troy; Yang, Lynda J-S

2017-10-01

Offering real-time, high-resolution images via intraoperative ultrasound is advantageous for a variety of peripheral nerve applications. To highlight the advantages of ultrasound, its extraoperative uses are reviewed. The current intraoperative uses, including nerve localization, real-time evaluation of peripheral nerve tumors, and implantation of leads for peripheral nerve stimulation, are reviewed. Although intraoperative peripheral nerve localization has been performed previously using guide wires and surgical dyes, the authors' approach using ultrasound-guided instrument clamps helps guide surgical dissection to the target nerve, which could lead to more timely operations and shorter incisions. Copyright © 2017 Elsevier Inc. All rights reserved.

Difference of ore-bearing and non-ore-bearing pegmatite in the Guangshigou area and its research significance

International Nuclear Information System (INIS)

Zuo Wenqian; Zhang Zhanshi; Sha Yazhou; Rao Chaojun

2011-01-01

Guangshigou uranium deposit is one of the typical granite-pegmatite uranium deposits in China, the ore-body are located in the density zone of the outside contact zone of granite pluton. To distinguish the ore-bearing and Non-ore-bearing pegmatite is one of the most practices and have great significance for the effect of mineral exploration. Based on the field investigation and former research results, contrast research on the characteristics of the pegmatite on petrology, geophysical, geochemistry and stable isotopes have been carried out. It is pointed out that the ore-bearing pegmatite differ from the non-ore-bearing one from macro-and-micro-view in Guangshigou Uranium deposits, the main characteristics are summarized; the macro-and-micro signs are established, the genetic difference between the ore-bearing and non-ore-bearing pegmatite are discussed primarily. The achievements would be helpful for prospecting and researching of this type uranium deposits in China. (authors)

Accuracy of Spindle Units with Hydrostatic Bearings

Directory of Open Access Journals (Sweden)

Fedorynenko Dmytro

2016-06-01

Full Text Available The work is devoted to the research of precision regularities in a spindle unit by the trajectory of the spindle installed on hydrostatic bearings. The mathematical model of trajectories spindle with lumped parameters that allows to define the position of the spindle with regard the simultaneous influence of design parameters, geometrical deviations ofform, temperature deformation bearing surfaces, the random nature of operational parameters and technical loads of hydrostatic bearings has been developed. Based on the results of numerical modeling the influence of shape errors of bearing surface of hydrostatic bearing on the statistical characteristics of the radius vector trajectories of the spindle by varying the values rotational speed of the spindle and oil pressure in front hydrostatic bearing has been developed. The obtained statistical regularities of precision spindle unit have been confirmed experimentally. It has been shown that an effective way to increase the precision of spindle units is to regulate the size of the gap in hydrostatic spindle bearings. The new design of an adjustable hydrostatic bearing, which can improve the accuracy of regulation size gap has been proposed.

36 CFR 13.1236 - Bear orientation.

Science.gov (United States)

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bear orientation. 13.1236 Section 13.1236 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR... Developed Area § 13.1236 Bear orientation. All persons visiting the BCDA must receive an NPS-approved Bear...

14 CFR 29.623 - Bearing factors.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 29.623 Section 29.623... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.623 Bearing factors. (a... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

Comparison of Chlorpyrifos-Oxon and Paraoxon Acetylcholinesterase Inhibition Dynamics: Potential role of a peripheral binding site

Energy Technology Data Exchange (ETDEWEB)

Kousba, Ahmed A.; Sultatos, L G.; Poet, Torka S.; Timchalk, Chuck

2004-08-02

The primary mechanism of action for organophosphorus (OP) insecticides involves the inhibition of acetylcholinesterase (AChE) by oxygenated metabolites (oxons). This inhibition has been attributed to the phosphorylation of the serine hydroxyl group located in the active site of the AChE molecule. The rate of phosphorylation is described by the bimolecular inhibitory rate constant (ki), which has been utilized for quantification of OP inhibitory capacity. It has been previously proposed that a peripheral binding site exists on the AChE molecule, which when occupied, reduces the capacity of additional oxon molecules to phosphorylate the active site. The objective of the current study was to evaluate the interaction of chlorpyrifos oxon (CPO) and paraoxon (PO) with rat brain AChE using a modified Ellman assay in conjunction with a pharmacodynamic model to further assess the dynamics of AChE inhibition and the potential role of a peripheral binding site. The ki for AChE inhibition determined at oxon concentrations of 5 x 10{sup -4} 100 nM were 0.212 and 0.0216 nM-1h-1 for CPO and PO, respectively. The spontaneous reactivation rates of the inhibited AChE for CPO and PO were 0.087 and 0.078 h-1, respectively. In contrast, the ki estimated at a low oxon concentration (1 pM) were {approx} 1,000 and 10,000 -fold higher than those determined at high CPO and PO concentrations, respectively. At these low concentrations, the ki estimates were approximately similar for both CPO and PO (180 and 250 nM-1h-1, respectively). This implies that at low exposure concentrations, both oxons exhibited similar inhibitory potency in contrast to the marked difference exhibited at higher concentrations, which is consistent with the presence of a peripheral binding site on the AChE enzyme. These results support the potential importance of a secondary binding site associated with AChE kinetics, particularly at low environmentally relevant concentrations.

[Advances in studies on bear bile powder].

Science.gov (United States)

Zhou, Chao-fan; Gao, Guo-jian; Liu, Ying

2015-04-01

In this paper, a detailed analysis was made on relevant literatures about bear bile powder in terms of chemical component, pharmacological effect and clinical efficacy, indicating bear bile powder's significant pharmacological effects and clinical application in treating various diseases. Due to the complex composition, bear bile powder is relatively toxic. Therefore, efforts shall be made to study bear bile powder's pharmacological effects, clinical application, chemical composition and toxic side-effects, with the aim to provide a scientific basis for widespread reasonable clinical application of bear bile powder.

Functional deficits in peripheral nerve mitochondria in rats with paclitaxel- and oxaliplatin-evoked painful peripheral neuropathy

OpenAIRE

Zheng, Huaien; Xiao, Wen Hua; Bennett, Gary J.

2011-01-01

Cancer chemotherapeutics like paclitaxel and oxaliplatin produce a dose-limiting chronic sensory peripheral neuropathy that is often accompanied by neuropathic pain. The cause of the neuropathy and pain is unknown. In animal models, paclitaxel-evoked and oxaliplatin-evoked painful peripheral neuropathies are accompanied by an increase in the incidence of swollen and vacuolated mitochondria in peripheral nerve axons. It has been proposed that mitochondrial swelling and vacuolation are indicati...

Mini-review: Far peripheral vision.

Science.gov (United States)

Simpson, Michael J

2017-11-01

The region of far peripheral vision, beyond 60 degrees of visual angle, is important to the evaluation of peripheral dark shadows (negative dysphotopsia) seen by some intraocular lens (IOL) patients. Theoretical calculations show that the limited diameter of an IOL affects ray paths at large angles, leading to a dimming of the main image for small pupils, and to peripheral illumination by light bypassing the IOL for larger pupils. These effects are rarely bothersome, and cataract surgery is highly successful, but there is a need to improve the characterization of far peripheral vision, for both pseudophakic and phakic eyes. Perimetry is the main quantitative test, but the purpose is to evaluate pathologies rather than characterize vision (and object and image regions are no longer uniquely related in the pseudophakic eye). The maximum visual angle is approximately 105 0 , but there is limited information about variations with age, race, or refractive error (in case there is an unexpected link with the development of myopia), or about how clear cornea, iris location, and the limiting retina are related. Also, the detection of peripheral motion is widely recognized to be important, yet rarely evaluated. Overall, people rarely complain specifically about this visual region, but with "normal" vision including an IOL for >5% of people, and increasing interest in virtual reality and augmented reality, there are new reasons to characterize peripheral vision more completely. Copyright © 2017 Elsevier Ltd. All rights reserved.

Magnetically leviated superconducting bearing

Science.gov (United States)

Weinberger, Bernard R.; Lynds, Jr., Lahmer

1993-01-01

A magnetically levitated superconducting bearing includes a magnet (2) mounted on a shaft (12) that is rotatable around an axis of rotation and a Type II superconductor (6) supported on a stator (14) in proximity to the magnet (2). The superconductor (6) is positioned so that when it is cooled to its superconducting state in the presence of a magnetic field, it interacts with the magnet (2) to produce an attractive force that levitates the magnet (2) and supports a load on the shaft (12). The interaction between the superconductor (6) and magnet(2) also produces surface screening currents (8) that generate a repulsive force perpendicular to the load. The bearing also has means for maintaining the superconductor at a temperature below its critical temperature (16, 18). The bearing could also be constructed so the magnet (2) is supported on the stator (14) and the superconductor (6) is mounted on the shaft (12). The bearing can be operated by cooling the superconductor (6) to its superconducting state in the presence of a magnetic field.

A theoretical-experimental study of backup bearings

DEFF Research Database (Denmark)

Lampe Linhares da Fonseca, Cesar Augusto

of two types of backup bearings, which are investigated experimentally and theoretically. The first type is a conventional ball bearing commonly used in industrial applications. The second is an unconventional bearing that, which contains pins inside the clearance for the rotor to impact on. The main...... both types of bearings for further investigation. Also, a full failure of the control and a rotor drop on the ball bearing as backup bearing is investigated by removing the magnetic forces. The nonlinear features of the dynamics of the rotor are assessed for different levels of unbalance. It has been...... radial forces. Remaining in this condition, it may lead to permanent damage or total failure of the machine. This is why the backup bearing design has to be carefully planned and investigated as to whether it helps to protect the integrity of the machine. This PhD thesis provides a comprehensive study...

Genomic sequencing of Pleistocene cave bears

Energy Technology Data Exchange (ETDEWEB)

Noonan, James P.; Hofreiter, Michael; Smith, Doug; Priest, JamesR.; Rohland, Nadin; Rabeder, Gernot; Krause, Johannes; Detter, J. Chris; Paabo, Svante; Rubin, Edward M.

2005-04-01

Despite the information content of genomic DNA, ancient DNA studies to date have largely been limited to amplification of mitochondrial DNA due to technical hurdles such as contamination and degradation of ancient DNAs. In this study, we describe two metagenomic libraries constructed using unamplified DNA extracted from the bones of two 40,000-year-old extinct cave bears. Analysis of {approx}1 Mb of sequence from each library showed that, despite significant microbial contamination, 5.8 percent and 1.1 percent of clones in the libraries contain cave bear inserts, yielding 26,861 bp of cave bear genome sequence. Alignment of this sequence to the dog genome, the closest sequenced genome to cave bear in terms of evolutionary distance, revealed roughly the expected ratio of cave bear exons, repeats and conserved noncoding sequences. Only 0.04 percent of all clones sequenced were derived from contamination with modern human DNA. Comparison of cave bear with orthologous sequences from several modern bear species revealed the evolutionary relationship of these lineages. Using the metagenomic approach described here, we have recovered substantial quantities of mammalian genomic sequence more than twice as old as any previously reported, establishing the feasibility of ancient DNA genomic sequencing programs.

14 CFR 27.623 - Bearing factors.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 27.623 Section 27.623... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

14 CFR 25.623 - Bearing factors.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 25.623 Section 25.623... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

Determination of hydroxylated polycyclic aromatic hydrocarbons by HPLC-photoionization tandem mass spectrometry in wood smoke particles and soil samples.

Science.gov (United States)

Avagyan, Rozanna; Nyström, Robin; Boman, Christoffer; Westerholm, Roger

2015-06-01

A simple and fast method for analysis of hydroxylated polycyclic aromatic hydrocarbons using pressurized liquid extraction and high performance liquid chromatography utilizing photoionization tandem mass spectrometry was developed. Simultaneous separation and determination of nine hydroxylated polycyclic aromatic hydrocarbons and two hydroxy biphenyls could be performed in negative mode with a run time of 12 min, including equilibration in 5 min. The calibration curves were in two concentration ranges; 1-50 ng/mL and 0.01-50 μg/mL, with coefficients of correlation R (2) > 0.997. The limits of detection and method quantification limits were in the range of 9-56 pg and 5-38 ng/g, respectively. A two-level full factorial experimental design was used for screening of conditions with the highest impact on the extraction. The extraction procedure was automated and suitable for a large number of samples. The extraction recoveries ranged from 70 to 102 % and the matrix effects were between 92 and 104 %. The overall method was demonstrated on wood smoke particles and soil samples with good analytical performance, and five OH-PAHs were determined in the concentration range of 0.19-210 μg/g. As far as we know, hydroxylated polycyclic aromatic hydrocarbons were determined in wood smoke and soil samples using photoionization mass spectrometry for the first time in this present study. Accordingly, this study shows that high performance liquid chromatography photoionization tandem mass spectrometry can be a good option for the determination of hydroxylated polycyclic aromatic hydrocarbons in complex environmental samples. Graphical Abstract The method developed in this study was used to determine hydroxylated polycyclic aromatic hydrocarbons in wood smoke and soil.

Modelling On Photogeneration Of Hydroxyl Radical In Surface Waters And Its Reactivity Towards Pharmaceutical Wastes

International Nuclear Information System (INIS)

Das, Radha; Vione, Davide; Rubertelli, Francesca; Maurino, Valter; Minero, Claudio; Barbati, Stephane; Chiron, Serge

2010-01-01

This paper reports a simple model to describe the formation and reactivity of hydroxyl radicals in the whole column of freshwater lakes. It is based on empirical irradiation data and is a function of the water chemical composition (the photochemically significant parameters NPOC, nitrate, nitrite, carbonate and bicarbonate), the lake conformation best expressed as the average depth, and the water absorption spectrum in a simplified Lambert-Beer approach. The purpose is to derive the lifetime of dissolved molecules, due to reaction with OH, on the basis of their second-order rate constants with the hydroxyl radical. The model was applied to two compounds of pharmaceutical wastes ibuprofen and carbamazepine, for which the second-order rate constants for reaction with the hydroxyl radical were measured by means of the competition kinetics with 2-propanol. The measured values of the rate constants are 1.0x10 10 and 1.6x10 10 M -1 s -1 for ibuprofen and carbamazepine, respectively. The model suggests that the lifetime of a given compound can be very variable in different lakes, even more than the lifetime of different compounds in the same lake. It can be concluded that as far as the reaction with OH, is concerned the concepts of photolability and photostability, traditionally attached to definite compounds, are ecosystem-dependent at least as much as they depend on the molecule under consideration.

Grease lubrication in rolling bearings

CERN Document Server

Lugt, Piet M

2012-01-01

The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

NDUFAF5 Hydroxylates NDUFS7 at an Early Stage in the Assembly of Human Complex I*

Science.gov (United States)

Rhein, Virginie F.; Carroll, Joe; Ding, Shujing; Fearnley, Ian M.; Walker, John E.

2016-01-01

Complex I (NADH ubiquinone oxidoreductase) in mammalian mitochondria is an L-shaped assembly of 45 proteins. One arm lies in the inner membrane, and the other extends about 100 Å into the matrix of the organelle. The extrinsic arm contains binding sites for NADH, the primary electron acceptor FMN, and seven iron-sulfur clusters that form a pathway for electrons linking FMN to the terminal electron acceptor, ubiquinone, which is bound in a tunnel in the region of the junction between the arms. The membrane arm contains four antiporter-like domains, energetically coupled to the quinone site and involved in pumping protons from the matrix into the intermembrane space contributing to the proton motive force. Seven of the subunits, forming the core of the membrane arm, are translated from mitochondrial genes, and the remaining subunits, the products of nuclear genes, are imported from the cytosol. Their assembly is coordinated by at least thirteen extrinsic assembly factor proteins that are not part of the fully assembled complex. They assist in insertion of co-factors and in building up the complex from smaller sub-assemblies. One such factor, NDUFAF5, belongs to the family of seven-β-strand S-adenosylmethionine-dependent methyltransferases. However, similar to another family member, RdmB, it catalyzes the introduction of a hydroxyl group, in the case of NDUFAF5, into Arg-73 in the NDUFS7 subunit of human complex I. This modification occurs early in the pathway of assembly of complex I, before the formation of the juncture between peripheral and membrane arms. PMID:27226634

Magnetic translator bearings

Science.gov (United States)

Hockney, Richard L. (Inventor); Downer, James R. (Inventor); Eisenhaure, David B. (Inventor); Hawkey, Timothy J. (Inventor); Johnson, Bruce G. (Inventor)

1990-01-01

A magnetic bearing system for enabling translational motion includes a carriage and a shaft for movably supporting the carriage; a first magnetic bearing fixed to one of the carriage and shaft and slidably received in a first channel of the other of the carriage and shaft. The first channel is generally U shaped with two side walls and a back wall. The magnetic bearing includes a pair of spaced magnetic pole pieces, each pole piece having a pair of electromagnetic coils mounted on poles on opposite ends of the pole piece proximate the side walls, and a third electromagnetic coil mounted on a pole of the pole piece proximate the backwall; a motion sensor for sensing translational motion along two axes and rotationally about three axes of the carriage and shaft relative to each other; and a correction circuit responsive to the sensor for generating a correction signal to drive the coils to compensate for any misalignment sensed between the carriage and the shaft.

Delayed child-bearing.

Science.gov (United States)

Johnson, Jo-Ann; Tough, Suzanne

2012-01-01

To provide an overview of delayed child-bearing and to describe the implications for women and health care providers. Delayed child-bearing, which has increased greatly in recent decades, is associated with an increased risk of infertility, pregnancy complications, and adverse pregnancy outcome. This guideline provides information that will optimize the counselling and care of Canadian women with respect to their reproductive choices. Maternal age is the most important determinant of fertility, and obstetric and perinatal risks increase with maternal age. Many women are unaware of the success rates or limitations of assisted reproductive technology and of the increased medical risks of delayed child-bearing, including multiple births, preterm delivery, stillbirth, and Caesarean section. This guideline provides a framework to address these issues. Studies published between 2000 and August 2010 were retrieved through searches of PubMed and the Cochrane Library using appropriate key words (delayed child-bearing, deferred pregnancy, maternal age, assisted reproductive technology, infertility, and multiple births) and MeSH terms (maternal age, reproductive behaviour, fertility). The Internet was also searched using similar key words, and national and international medical specialty societies were searched for clinical practice guidelines and position statements. Data were extracted based on the aims, sample, authors, year, and results. The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). The Society of Obstetricians and Gynaecologists of Canada. RECOMMENDATIONS 1. Women who delay child-bearing are at increased risk of infertility. Prospective parents, especially women, should know that their fecundity and fertility begin to decline significantly after 32 years of age. Prospective parents should know that assisted reproductive technologies cannot guarantee a live birth or completely

Actuators for Active Magnetic Bearings

Directory of Open Access Journals (Sweden)

Eric H. Maslen

2017-10-01

Full Text Available The literature of active magnetic bearing (AMB technology dates back to at least 1937 when the earliest work that clearly describes an active magnetic bearing system was published by Jesse Beams [...

Tumefactive appearance of peripheral nerve involvement in hematologic malignancies: a new imaging association

Energy Technology Data Exchange (ETDEWEB)

Capek, Stepan [Mayo Clinic, Department of Neurosurgery, Rochester, Minnesota (United States); St. Anne' s University Hospital Brno, International Clinical Research Center, Brno (Czech Republic); Hebert-Blouin, Marie-Noelle [McGill University, Department of Neurologic Surgery, Montreal, Quebec (Canada); Puffer, Ross C.; Spinner, Robert J. [Mayo Clinic, Department of Neurosurgery, Rochester, Minnesota (United States); Martinoli, Carlo [Universita degli Studi di Genova, Department of Radiology, Genova (Italy); Frick, Matthew A.; Amrami, Kimberly K. [Mayo Clinic, Department of Radiology, Rochester, MN (United States)

2015-04-29

In neurolymphomatosis (NL), the affected nerves are typically described to be enlarged and hyperintense on T2W MR sequences and to avidly enhance on gadolinium-enhanced T1WI. This pattern is highly non-specific. We recently became aware of a ''tumefactive pattern'' of NL, neuroleukemiosis (NLK) and neuroplasmacytoma (NPLC), which we believe is exclusive to hematologic diseases affecting peripheral nerves. We defined a ''tumefactive'' appearance as complex, fusiform, hyperintense on T2WI, circumferential tumor masses encasing the involved peripheral nerves. The nerves appear to be infiltrated by the tumor. Both structures show varying levels of homogenous enhancement. We reviewed our series of 52 cases of NL in search of this pattern; two extra outside cases of NL, three cases of NLK, and one case of NPLC were added to the series. We identified 20 tumefactive lesions in 18 patients (14 NL, three NLK, one NPLC). The brachial plexus (n = 7) was most commonly affected, followed by the sciatic nerve (n = 6) and lumbosacral plexus (n = 3). Four patients had involvement of other nerves. All were proven by biopsy: the diagnosis was high-grade lymphoma (n = 12), low-grade lymphoma (n = 3), acute leukemia (n = 2), and plasmacytoma (n = 1). We present a new imaging pattern of ''tumefactive'' neurolymphomatosis, neuroleukemiosis, or neuroplasmacytoma in a series of 18 cases. We believe this pattern is associated with hematologic diseases directly involving the peripheral nerves. Knowledge of this association can provide a clue to clinicians in establishing the correct diagnosis. Bearing in mind that tumefactive NL, NLK, and NPLC is a newly introduced imaging pattern, we still recommend to biopsy patients with suspicion of a malignancy. (orig.)

Performance of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped flexibly mounted spiral-groove thrust bearing

Science.gov (United States)

Ream, L. W.

1974-01-01

A test program was conducted to determine the performance characteristics of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped spiral-groove thrust bearing designed for the Brayton cycle rotating unit (BRU). Hydrostatic, hybrid (simultaneously hydrostatic and hydrodynamic), and hydrodynamic tests were conducted in argon gas at ambient pressure and temperature ranges representative of operation to the 10.5 kWe BRU power-generating level. Performance of the gas lubricated bearings is presented including hydrostatic gas flow rates, bearing clearances, bearing temperatures, and transient performance.

14 CFR 23.623 - Bearing factors.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 23.623 Section 23.623... Bearing factors. (a) Each part that has clearance (free fit), and that is subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of normal relative motion. (b) For...

Hydroxyl radical and ozone initiated photochemical reactions of 1,3-butadiene

Science.gov (United States)

Liu, Xiaoyu; Jeffries, Harvey E.; Sexton, Kenneth G.

1,3-Butadiene, classified as hazardous in the 1990 Clean Air Act Amendments, is an important ambient air pollutant. Understanding its atmospheric transformation is useful for its own sake, and is also helpful for eliciting isoprene's fate in the atmosphere (isoprene dominates the biogenic emissions in US). In this paper, samples from both hydroxyl- and ozone-initiated photooxidation of 1,3-butadiene were analyzed by derivatization with O- (2,3,4,5,6-pentafluorobenzyl)-hydroxylamine followed by separation and detection by gas chromatography/ion trap mass spectrometry to detect and identify carbonyl compounds. The following carbonyls were observed: formaldehyde, acrolein, glycolaldehyde, glycidaldehyde, 3-hydroxy-propanaldehyde, hydroxy acetone, and malonaldehyde, which can be classified into three categories: epoxy carbonyls, hydroxyl carbonyls, and di-carbonyls. Three non-carbonyls, furan, 1,3-buatdiene monoxide, and 1,3-butadiene diepoxide, were also found. To confirm their identities, both commercially available and synthesized standards were used. To investigate the mechanism of 1,3-butadiene, separate batch reactor experiments for acrolein and 1,3-butadiene monoxide were carried out. Time series samples for several products were also taken. When necessary, computational chemistry methods were also employed. Based on these results, various schemes for the reaction mechanism are proposed.

Hydrostatic bearing with a stepped duct

International Nuclear Information System (INIS)

Krevsun, Eh.P.; Ivanov, A.A.

1975-01-01

A method for calculating and experimental data from tests on a hydrostatic bearing whose operating hydraulic channel is formed by two cylincrical surfaces, are presented. Unlike currently used hydrostatic bearings, the bearing described has no capillary choke or diaphragm choke at the entrance. This simplifies the construction and increases the reliability, especially when it is operated with corrosive liquids or liquids containing solid suspensoids and causing erosion and blockage of the choke structures. In order to obtain the calculated relations, the flow of a liquid from the bearing in the axial direction to one side through a part of an aperture of unit width was examined. The effect of rotating the axle, of flow in the circumferential direction, and curvature of the aperture was not considered. Isothermal and laminar flows were considered. Because of the simplicity of the hydraulic circuit and the satisfactory properties (bearing capability and flow rate), the bearing described may be used in pumps operating with corrosive liquids, with those containing solid suspensoids and in nuclear energy establishments. (author)

DW_BEAR

Data.gov (United States)

Department of Homeland Security — Subset of BEAR (Bi-Weekly Examination Analysis and Reporting) data used for financial audit remediation reporting within the Coast Guard Business Intelligence (CGBI)...

Long term clinical outcome of peripheral nerve stimulation in patients with chronic peripheral neuropathic pain

DEFF Research Database (Denmark)

Calenbergh, F. Van; Gybels, J.; Laere, K. Van

2009-01-01

BACKGROUND: Chronic neuropathic pain after injury to a peripheral nerve is known to be resistant to treatment. Peripheral nerve stimulation is one of the possible treatment options, which is, however, not performed frequently. In recent years we have witnessed a renewed interest for PNS. The aim...... of the present study was to evaluate the long-term clinical efficacy of PNS in a group of patients with peripheral neuropathic pain treated with PNS since the 1980s. METHODS: Of an original series of 11 patients, 5 patients could be invited for clinical examination, detailed assessment of clinical pain and QST...... functioning) also showed positive effects. Quantitative Sensory Testing results did not show significant differences in cold pain and heat pain thresholds between the "ON" and "OFF" conditions. CONCLUSION: In selected patients with peripheral neuropathic pain PNS remains effective even after more than 20...

Bearing-Mounting Concept Accommodates Thermal Expansion

Science.gov (United States)

Nespodzany, Robert; Davis, Toren S.

1995-01-01

Pins or splines allow radial expansion without slippage. Design concept for mounting rotary bearing accommodates differential thermal expansion between bearing and any structure(s) to which bearing connected. Prevents buildup of thermal stresses by allowing thermal expansion to occur freely but accommodating expansion in such way not to introduce looseness. Pin-in-slot configuration also maintains concentricity.

Blade Bearing Friction Estimation of Operating Wind Turbines

DEFF Research Database (Denmark)

Perisic, Nevena; Pedersen, Bo Juul; Kirkegaard, Poul Henning

2012-01-01

Blade root bearing on a wind turbine (WTG) enables pitching of blades for power control and rotor braking and is a WTG critical component. As the size of modern WTGs is constantly increasing, this leads to relatively less rigid bearings, more sensitive to deformations, thus WTG operational...... reliability can be increased by continuous monitoring of blade bearing. High blade bearing friction is undesirable, as it may be associated with excessive heating of the surfaces, damage and/or inefficient operation. Thus, continuous observation of bearing friction level is crucial for blade bearing health...... monitoring systems. A novel algorithm for online monitoring of bearing friction level is developed combining physical knowledge about pitch system dynamics with state estimator, i.e. observer theory and signal processing assuming realistic sensor availability. Results show estimation of bearing friction...

Mechanistic and structural basis of stereospecific Cbeta-hydroxylation in calcium-dependent antibiotic, a daptomycin-type lipopeptide.

Science.gov (United States)

Strieker, Matthias; Kopp, Florian; Mahlert, Christoph; Essen, Lars-Oliver; Marahiel, Mohamed A

2007-03-20

Non-ribosomally synthesized lipopeptide antibiotics of the daptomycin type are known to contain unnatural beta-modified amino acids, which are essential for bioactivity. Here we present the biochemical and structural basis for the incorporation of 3-hydroxyasparagine at position 9 in the 11-residue acidic lipopeptide lactone calcium-dependent antibiotic (CDA). Direct hydroxylation of l-asparagine by AsnO, a non-heme Fe(2+)/alpha-ketoglutarate-dependent oxygenase encoded by the CDA biosynthesis gene cluster, was validated by Fmoc derivatization of the reaction product and LC/MS analysis. The 1.45, 1.92, and 1.66 A crystal structures of AsnO as apoprotein, Fe(2+) complex, and product complex, respectively, with (2S,3S)-3-hydroxyasparagine and succinate revealed the stereoselectivity and substrate specificity of AsnO. The comparison of native and product-complex structures of AsnO showed a lid-like region (residues F208-E223) that seals the active site upon substrate binding and shields it from sterically demanding peptide substrates. Accordingly, beta-hydroxylated asparagine is synthesized prior to its incorporation into the growing CDA peptide. The AsnO structure could serve as a template for engineering novel enzymes for the synthesis of beta-hydroxylated amino acids.

Hydroxylation of p-substituted phenols by tyrosinase: Further insight into the mechanism of tyrosinase activity

Energy Technology Data Exchange (ETDEWEB)

Munoz-Munoz, Jose Luis [GENZ - Grupo de Investigacion Enzimologia, Departamento de Bioquimica y Biologia Molecular-A, Facultad de Biologia, Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Berna, Jose [Grupo de Quimica Organica Sintetica, Departamento de Quimica Organica, Facultad de Quimica Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia (Spain); Garcia-Molina, Maria del Mar; Garcia-Molina, Francisco [GENZ - Grupo de Investigacion Enzimologia, Departamento de Bioquimica y Biologia Molecular-A, Facultad de Biologia, Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Garcia-Ruiz, Pedro Antonio [QCPAI - Grupo de Quimica de Carbohidratos, Polimeros y Aditivos Industriales, Departamento de Quimica Organica, Facultad de Quimica Campus Internacional de Excelencia Campus Mare Nostrum, Universidad de Murcia (Spain); Varon, Ramon [Departamento de Quimica-Fisica, Escuela de Ingenieros Industriales de Albacete, Universidad de Castilla la Mancha, Avda. Espana s/n. Campus Universitario, E-02071 Albacete (Spain); and others

2012-07-27

Highlights: Black-Right-Pointing-Pointer The action the copper complexes and tyrosinase on phenols is equivalent. Black-Right-Pointing-Pointer Isotope effect showed that nucleophilic attack to copper atom may be the slower step. Black-Right-Pointing-Pointer The value of {rho} (Hammett constant) supports an electrophilic aromatic substitution. Black-Right-Pointing-Pointer Data obtained in steady state pH 7 conditions support the mechanism of Scheme 1SM. -- Abstract: A study of the monophenolase activity of tyrosinase by measuring the steady state rate with a group of p-substituted monophenols provides the following kinetic information: k{sub cat}{sup m} and the Michaelis constant, K{sub M}{sup m}. Analysis of these data taking into account chemical shifts of the carbon atom supporting the hydroxyl group ({delta}) and {sigma}{sub p}{sup +}, enables a mechanism to be proposed for the transformation of monophenols into o-diphenols, in which the first step is a nucleophilic attack on the copper atom on the form E{sub ox} (attack of the oxygen of the hydroxyl group of C-1 on the copper atom) followed by an electrophilic attack (attack of the hydroperoxide group on the ortho position with respect to the hydroxyl group of the benzene ring, electrophilic aromatic substitution with a reaction constant {rho} of -1.75). These steps show the same dependency on the electronic effect of the substituent groups in C-4. Furthermore, a study of a solvent deuterium isotope effect on the oxidation of monophenols by tyrosinase points to an appreciable isotopic effect. In a proton inventory study with a series of p-substituted phenols, the representation of k{sub cat}{sup f{sub n}}/k{sub cat}{sup f{sub 0}} against n (atom fractions of deuterium), where k{sub cat}{sup f{sub n}} is the catalytic constant for a molar fraction of deuterium (n) and k{sub cat}{sup f{sub 0}} is the corresponding kinetic parameter in a water solution, was linear for all substrates. These results indicate that

Unusual spin-trap chemistry for the reaction of hydroxyl radical with the carcinogen N-nitrosodimethylamine

Energy Technology Data Exchange (ETDEWEB)

Wink, D A [National Cancer Inst., Frederick, MD (United States); Desrosiers, M F [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1991-01-01

The reaction of the potent carcinogen N-nitrosodimethylamine (NDMA) with hydroxyl radical generated via radiolysis was studied using EPR techniques. Attempts to spin trap NDMA radical intermediates with 3.5-dibromo-4-nitrosobenzene sulfonate (DBNBS) produced only unusual DBNBS radicals. One of these radicals was shown to be generated by both reaction of DBNBS with nitric oxide, and direct oxidation of DBNBS with an inorganic oxidant (BR{sub 2}{sup -}). Another DBNBS radical was identified as a sulfite spin adduct resulting from the degradation of DBNBS by a NDMA reactive inter-mediate. In the absence of DBNBS, hydroxyl radical reaction with NDMA gave the dimethylnitroxide produced an EPR spectrum nearly identical to that of NDMA solutions with DBNBS added before radiolysis. A proposed mechanism accounting for these observations is presented. (author).

Unusual spin-trap chemistry for the reaction of hydroxyl radical with the carcinogen N-nitrosodimethylamine

International Nuclear Information System (INIS)

Wink, D.A.; Desrosiers, M.F.

1991-01-01

The reaction of the potent carcinogen N-nitrosodimethylamine (NDMA) with hydroxyl radical generated via radiolysis was studied using EPR techniques. Attempts to spin trap NDMA radical intermediates with 3.5-dibromo-4-nitrosobenzene sulfonate (DBNBS) produced only unusual DBNBS radicals. One of these radicals was shown to be generated by both reaction of DBNBS with nitric oxide, and direct oxidation of DBNBS with an inorganic oxidant (BR 2 - ). Another DBNBS radical was identified as a sulfite spin adduct resulting from the degradation of DBNBS by a NDMA reactive inter-mediate. In the absence of DBNBS, hydroxyl radical reaction with NDMA gave the dimethylnitroxide produced an EPR spectrum nearly identical to that of NDMA solutions with DBNBS added before radiolysis. A proposed mechanism accounting for these observations is presented. (author)

Percutaneous Augmented Peripheral Osteoplasty in Long Bones of Oncologic Patients for Pain Reduction and Prevention of Impeding Pathologic Fracture: The Rebar Concept

International Nuclear Information System (INIS)

Kelekis, A.; Filippiadis, D.; Anselmetti, G.; Brountzos, E.; Mavrogenis, A.; Papagelopoulos, P.; Kelekis, N.; Martin, J.-B.

2016-01-01

PurposeTo evaluate clinical efficacy/safety of augmented peripheral osteoplasty in oncologic patients with long-term follow-up.Materials and MethodsPercutaneous augmented peripheral osteoplasty was performed in 12 patients suffering from symptomatic lesions of long bones. Under extensive local sterility measures, anesthesiology care, and fluoroscopic guidance, direct access to lesion was obtained and coaxially a metallic mesh consisting of 25–50 medical grade stainless steel micro-needles (22 G, 2–6 cm length) was inserted. PMMA for vertebroplasty was finally injected under fluoroscopic control. CT assessed implant position 24-h post-treatment.ResultsClinical evaluation included immediate and delayed follow-up studies of patient’s general condition, NVS pain score, and neurological status. Imaging assessed implant’s long-term stability. Mean follow-up was 16.17 ± 10.93 months (range 2–36 months). Comparing patients’ scores prior (8.33 ± 1.67 NVS units) and post (1.42 ± 1.62 NVS units) augmented peripheral osteoplasty, there was a mean decrease of 6.92 ± 1.51 NVS units. Overall mobility improved in 12/12 patients. No complication was observed.ConclusionPercutaneous augmented peripheral osteoplasty (rebar concept) for symptomatic malignant lesions in long bones seems to be a possible new technique for bone stabilization. This combination seems to provide necessary stability against shearing forces applied in long bones during weight bearing

Percutaneous Augmented Peripheral Osteoplasty in Long Bones of Oncologic Patients for Pain Reduction and Prevention of Impeding Pathologic Fracture: The Rebar Concept

Energy Technology Data Exchange (ETDEWEB)

Kelekis, A., E-mail: akelekis@med.uoa.gr; Filippiadis, D., E-mail: dfilippiadis@yahoo.gr [University General Hospital “ATTIKON”, 2nd Radiology Department (Greece); Anselmetti, G., E-mail: gc.anselmetti@fastwebnet.it [GVM Care and Research Maria Pia Hospital (Italy); Brountzos, E., E-mail: ebrountz@med.uoa.gr [University General Hospital “ATTIKON”, 2nd Radiology Department (Greece); Mavrogenis, A., E-mail: afm@otenet.gr; Papagelopoulos, P., E-mail: pjp@hol.gr [University General Hospital “ATTIKON”, A Orthopedic Clinic (Greece); Kelekis, N., E-mail: kelnik@med.uoa.gr [University General Hospital “ATTIKON”, 2nd Radiology Department (Greece); Martin, J.-B., E-mail: jbmartin@cird.ch [Centre Imaginerie Rive Droite & Gauche (Switzerland)

2016-01-15

PurposeTo evaluate clinical efficacy/safety of augmented peripheral osteoplasty in oncologic patients with long-term follow-up.Materials and MethodsPercutaneous augmented peripheral osteoplasty was performed in 12 patients suffering from symptomatic lesions of long bones. Under extensive local sterility measures, anesthesiology care, and fluoroscopic guidance, direct access to lesion was obtained and coaxially a metallic mesh consisting of 25–50 medical grade stainless steel micro-needles (22 G, 2–6 cm length) was inserted. PMMA for vertebroplasty was finally injected under fluoroscopic control. CT assessed implant position 24-h post-treatment.ResultsClinical evaluation included immediate and delayed follow-up studies of patient’s general condition, NVS pain score, and neurological status. Imaging assessed implant’s long-term stability. Mean follow-up was 16.17 ± 10.93 months (range 2–36 months). Comparing patients’ scores prior (8.33 ± 1.67 NVS units) and post (1.42 ± 1.62 NVS units) augmented peripheral osteoplasty, there was a mean decrease of 6.92 ± 1.51 NVS units. Overall mobility improved in 12/12 patients. No complication was observed.ConclusionPercutaneous augmented peripheral osteoplasty (rebar concept) for symptomatic malignant lesions in long bones seems to be a possible new technique for bone stabilization. This combination seems to provide necessary stability against shearing forces applied in long bones during weight bearing.

The shared preference niche of sympatric Asiatic black bears and sun bears in a tropical forest mosaic.

Science.gov (United States)

Steinmetz, Robert; Garshelis, David L; Chutipong, Wanlop; Seuaturien, Naret

2011-01-20

Ecologically similar species often coexist by partitioning use of habitats or resources. Such partitioning can occur through divergent or shared niches. We investigated overlap in habitat use and spatial co-occurrence by sympatric Asiatic black bears and sun bears in three habitats in Thailand, and thereby assessed which niche model best accounts for their coexistence. We used density of species-specific signs to assess habitat use. Signs of both bear species occurred in all three habitats, and on >60% of sampling transects. Both species fed mostly on fruit; insect feeding signs were uncommon, and were mostly from sun bears. Significant differences in habitat use occurred only in montane forest, the habitat in which fruit was most abundant; incidence of black bear sign there was six times higher than that of sun bears. Habitat use was similar between the two species in the other habitats, which comprised 85% of the area. Of 10 habitat attributes examined, fruiting tree density was the best predictor of occurrence for both species. Models that included interspecific competition (fresh foraging activity of the other species) were less supported than the top models without competition. Bear species co-occurrence at both coarse and fine spatial scales and use of the same resources (fruit trees) indicated common niche preferences. However, their habitat use differed in ways expected from their physical differences: larger black bears dominated in the most fruit-rich habitat, and smaller sun bears used less-preferred insects. These results indicate broadly overlapping fundamental niches combined with asymmetric competition-features consistent with the concept of shared preference niches. This model of the niche has received little attention in ecology, but appears to be relatively common in nature.

The shared preference niche of sympatric Asiatic black bears and sun bears in a tropical forest mosaic.

Directory of Open Access Journals (Sweden)

Robert Steinmetz

2011-01-01

Full Text Available Ecologically similar species often coexist by partitioning use of habitats or resources. Such partitioning can occur through divergent or shared niches. We investigated overlap in habitat use and spatial co-occurrence by sympatric Asiatic black bears and sun bears in three habitats in Thailand, and thereby assessed which niche model best accounts for their coexistence.We used density of species-specific signs to assess habitat use. Signs of both bear species occurred in all three habitats, and on >60% of sampling transects. Both species fed mostly on fruit; insect feeding signs were uncommon, and were mostly from sun bears. Significant differences in habitat use occurred only in montane forest, the habitat in which fruit was most abundant; incidence of black bear sign there was six times higher than that of sun bears. Habitat use was similar between the two species in the other habitats, which comprised 85% of the area. Of 10 habitat attributes examined, fruiting tree density was the best predictor of occurrence for both species. Models that included interspecific competition (fresh foraging activity of the other species were less supported than the top models without competition.Bear species co-occurrence at both coarse and fine spatial scales and use of the same resources (fruit trees indicated common niche preferences. However, their habitat use differed in ways expected from their physical differences: larger black bears dominated in the most fruit-rich habitat, and smaller sun bears used less-preferred insects. These results indicate broadly overlapping fundamental niches combined with asymmetric competition-features consistent with the concept of shared preference niches. This model of the niche has received little attention in ecology, but appears to be relatively common in nature.

77 FR 59639 - Bear Lake National Wildlife Refuge, Bear Lake County, ID and Oxford Slough Waterfowl Production...

Science.gov (United States)

2012-09-28

... by 2020 to reduce the sedimentation rate of Bear River water diversions and to better exclude carp... sedimentation rate of Bear River water diversions and better exclude carp from Refuge wetlands. As in... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service [FWS-R1-R-2012-N095; 1265-0000-10137-S3] Bear...

Rotor Rolling over a Water-Lubricated Bearing

Science.gov (United States)

Shatokhin, V. F.

2018-02-01

The article presents the results of studying the effect of forces associated with secondary damping coefficients (gyroscopic forces) on the development of asynchronous rolling of the rotor over a water-lubricated bearing. The damping forces act against the background of other exciting forces in the rotor-supports system, in particular, the exciting forces of contact interaction between the rotor and bearing. The article considers a rotor resting on supports rubbing against the bearing and the occurrence of self-excited vibration in the form of asynchronous roll-over. The rotor supports are made in the form of plain-type water-lubricated bearings. The plain-type bearing's lubrication stiffness and damping forces are determined using the wellknown algorithms taking into account the physical properties of water serving as lubrication of the bearing. The bearing sliding pair is composed of refractory materials. The lubrication layer in such bearings is thinner than that used in oil-lubricated bearings with white metal lining, and there is no white metal layer in waterlubricated bearings. In case of possible deviations from normal operation of the installation, the rotating rotor comes into direct contact with the liner's rigid body. Unsteady vibrations are modeled using a specially developed software package for calculating the vibration of rotors that rub against the turbine (pump) stator elements. The stiffness of the bearing liner with the stator support structure is specified by a dependence in the force-deformation coordinate axes. In modeling the effect of damping forces, the time moment corresponding to the onset of asynchronous rolling-over with growing vibration amplitudes is used as the assessment criterion. With a longer period of time taken for the rolling-over to develop, it becomes possible to take the necessary measures in response to actuation of the equipment set safety system, which require certain time for implementing them. It is shown that the

Rolling Bearing Life Prediction, Theory, and Application

Science.gov (United States)

Zaretsky, Erwin V.

2016-01-01

A tutorial is presented outlining the evolution, theory, and application of rolling-element bearing life prediction from that of A. Palmgren, 1924; W. Weibull, 1939; G. Lundberg and A. Palmgren, 1947 and 1952; E. Ioannides and T. Harris, 1985; and E. Zaretsky, 1987. Comparisons are made between these life models. The Ioannides-Harris model without a fatigue limit is identical to the Lundberg-Palmgren model. The Weibull model is similar to that of Zaretsky if the exponents are chosen to be identical. Both the load-life and Hertz stress-life relations of Weibull, Lundberg and Palmgren, and Ioannides and Harris reflect a strong dependence on the Weibull slope. The Zaretsky model decouples the dependence of the critical shear stress-life relation from the Weibull slope. This results in a nominal variation of the Hertz stress-life exponent. For 9th- and 8th-power Hertz stress-life exponents for ball and roller bearings, respectively, the Lundberg-Palmgren model best predicts life. However, for 12th- and 10th-power relations reflected by modern bearing steels, the Zaretsky model based on the Weibull equation is superior. Under the range of stresses examined, the use of a fatigue limit would suggest that (for most operating conditions under which a rolling-element bearing will operate) the bearing will not fail from classical rolling-element fatigue. Realistically, this is not the case. The use of a fatigue limit will significantly overpredict life over a range of normal operating Hertz stresses. (The use of ISO 281:2007 with a fatigue limit in these calculations would result in a bearing life approaching infinity.) Since the predicted lives of rolling-element bearings are high, the problem can become one of undersizing a bearing for a particular application. Rules had been developed to distinguish and compare predicted lives with those actually obtained. Based upon field and test results of 51 ball and roller bearing sets, 98 percent of these bearing sets had acceptable

Remote detection of magmatic water in Bullialdus crater on the Moon

Science.gov (United States)

Klima, Rachel L.; Cahill, John; Hagerty, Justin J.; Lawrence, David

2013-01-01

Once considered dry compared with Earth, laboratory analyses of igneous components of lunar samples have suggested that the Moon’s interior is not entirely anhydrous. Water and hydroxyl have also been detected from orbit on the lunar surface, but these have been attributed to nonindigenous sources, such as interactions with the solar wind. Magmatic lunar volatiles—evidence for water indigenous to the lunar interior—have not previously been detected remotely. Here we analyse spectroscopic data from the Moon Mineralogy Mapper (M3) and report that the central peak of Bullialdus Crater is significantly enhanced in hydroxyl relative to its surroundings. We suggest that the strong and localized hydroxyl absorption features are inconsistent with a surficial origin. Instead, they are consistent with hydroxyl bound to magmatic minerals that were excavated from depth by the impact that formed Bullialdus Crater. Furthermore, estimates of thorium concentration in the central peak using data from the Lunar Prospector orbiter indicate an enhancement in incompatible elements, in contrast to the compositions of water-bearing lunar samples. We suggest that the hydroxyl-bearing material was excavated from a magmatic source that is distinct from that of samples analysed thus far.

Fractal analysis of polar bear hairs

Directory of Open Access Journals (Sweden)

Wang Qing-Li

2015-01-01

Full Text Available Hairs of a polar bear (Ursus maritimus are of superior properties such as the excellent thermal protection. Why do polar bears can resist such cold environment? The paper concludes that its fractal porosity plays an important role, and its fractal dimensions are very close to the golden mean, 1.618, revealing the possible optimal structure of polar bear hair.

Removable bearing arrangement for a wind turbine generator

Science.gov (United States)

Bagepalli, Bharat Sampathkumaran; Jansen, Patrick Lee; Gadre, Aniruddha Dattatraya

2010-06-15

A wind generator having removable change-out bearings includes a rotor and a stator, locking bolts configured to lock the rotor and stator, a removable bearing sub-assembly having at least one shrunk-on bearing installed, and removable mounting bolts configured to engage the bearing sub-assembly and to allow the removable bearing sub-assembly to be removed when the removable mounting bolts are removed.

Technology development for indigenous water lubricated bearings

International Nuclear Information System (INIS)

Limaye, P.K.; Soni, N.L.; Agrawal, R.G.

2010-01-01

Water Lubricated Bearings (WLB) are used in various mechanisms of fuel handling systems of PHWRs and AHWR. Availability and random failures of these bearings was a major factor in refuelling operations. Indigenous development of these bearings was taken up and 7 types of antifriction bearings in various sizes (totaling 37 variants) for PHWR, AHWR and Dhruva applications were successfully developed. This paper deals with various aspects of WLB development. (author)

Prediction of hydroxyl concentrations in cement pore water using a numerical cement hydration model

NARCIS (Netherlands)

Eijk, van R.J.; Brouwers, H.J.H.

2000-01-01

In this paper, a 3D numerical cement hydration model is used for predicting alkali and hydroxyl concentrations in cement pore water. First, this numerical model is calibrated for Dutch cement employing both chemical shrinkage and calorimetric experiments. Secondly, the strength development of some

Normal and sonographic anatomy of selected peripheral nerves. Part III: Peripheral nerves of the lower limb.

Science.gov (United States)

Kowalska, Berta; Sudoł-Szopińska, Iwona

2012-06-01

The ultrasonographic examination is currently increasingly used in imaging peripheral nerves, serving to supplement the physical examination, electromyography and magnetic resonance imaging. As in the case of other USG imaging studies, the examination of peripheral nerves is non-invasive and well-tolerated by patients. The typical ultrasonographic picture of peripheral nerves as well as the examination technique have been discussed in part I of this article series, following the example of the median nerve. Part II of the series presented the normal anatomy and the technique for examining the peripheral nerves of the upper limb. This part of the article series focuses on the anatomy and technique for examining twelve normal peripheral nerves of the lower extremity: the iliohypogastric and ilioinguinal nerves, the lateral cutaneous nerve of the thigh, the pudendal, sciatic, tibial, sural, medial plantar, lateral plantar, common peroneal, deep peroneal and superficial peroneal nerves. It includes diagrams showing the proper positioning of the sonographic probe, plus USG images of the successively discussed nerves and their surrounding structures. The ultrasonographic appearance of the peripheral nerves in the lower limb is identical to the nerves in the upper limb. However, when imaging the lower extremity, convex probes are more often utilized, to capture deeply-seated nerves. The examination technique, similarly to that used in visualizing the nerves of upper extremity, consists of locating the nerve at a characteristic anatomic reference point and tracking it using the "elevator technique". All 3 parts of the article series should serve as an introduction to a discussion of peripheral nerve pathologies, which will be presented in subsequent issues of the "Journal of Ultrasonography".

Local Attitudes towards Bear Management after Illegal Feeding and Problem Bear Activity

OpenAIRE

David Fraser; Sara Dubois

2013-01-01

Simple Summary The “pot bears” received international media attention in 2010 after police discovered the intentional feeding of black bears during the investigation of an alleged marijuana-growing operation in Christina Lake, British Columbia. Residents of this small community were surveyed by phone twice over the following year, before and after government actions. This study aimed to understand local attitudes on how these bears should be managed and whether they differed from existing bea...

Hydrogen exchange rate of tyrosine hydroxyl groups in proteins as studied by the deuterium isotope effect on C(zeta) chemical shifts.

Science.gov (United States)

Takeda, Mitsuhiro; Jee, Jungoo; Ono, Akira Mei; Terauchi, Tsutomu; Kainosho, Masatsune

2009-12-30

We describe a new NMR method for monitoring the individual hydrogen exchange rates of the hydroxyl groups of tyrosine (Tyr) residues in proteins. The method utilizes (2S,3R)-[beta(2),epsilon(1,2)-(2)H(3);0,alpha,beta,zeta-(13)C(4);(15)N]-Tyr, zeta-SAIL Tyr, to detect and assign the (13)C(zeta) signals of Tyr rings efficiently, either by indirect (1)H-detection through 7-8 Hz (1)H(delta)-(13)C(zeta) spin couplings or by direct (13)C(zeta) observation. A comparison of the (13)C(zeta) chemical shifts of three Tyr residues of an 18.2 kDa protein, EPPIb, dissolved in H(2)O and D(2)O, revealed that all three (13)C(zeta) signals in D(2)O appeared at approximately 0.13 ppm ( approximately 20 Hz at 150.9 MHz) higher than those in H(2)O. In a H(2)O/D(2)O (1:1) mixture, however, one of the three signals for (13)C(zeta) appeared as a single peak at the averaged chemical shifts, and the other two appeared as double peaks at exactly the same chemical shifts in H(2)O and D(2)O, in 50 mM phosphate buffer (pH 6.6) at 40 degrees C. These three peaks were assigned to Tyr-36, Tyr-120, and Tyr-30, from the lower to higher chemical shifts, respectively. The results indicate that the hydroxyl proton of Tyr-120 exchanges faster than a few milliseconds, whereas those of Tyr-30 and Tyr-36 exchange more slowly. The exchange rate of the Tyr-30 hydroxyl proton, k(ex), under these conditions was determined by (13)C NMR exchange spectroscopy (EXSY) to be 9.2 +/- 1.1 s(-1). The Tyr-36 hydroxyl proton, however, exchanges too slowly to be determined by EXSY. These profound differences among the hydroxyl proton exchange rates are closely related to their relative solvent accessibility and the hydrogen bonds associated with the Tyr hydroxyl groups in proteins.

Uranium-bearing wastes and their radon emanation

International Nuclear Information System (INIS)

Sasaki, Tomozo; Imamura, Mitsutaka; Gunji, Yasuyoshi

2007-01-01

There are no data available with regard to radon emanation coefficients for uranium-bearing wastes; such data are needed for the assessment of radiation exposure from radon that will be generated in the distant future as one uranium progeny at shallow land disposal sites for uranium-bearing wastes. There are many kinds of uranium-bearing wastes. However, it is not necessary to measure the radon emanation coefficients for all of them for two reasons. First, the radon emanation coefficients for uranium-bearing wastes contaminated by dissolved uranium are determined by the uranium chemical form, the manner of uranium deposition on the waste matrix, and the size of the particles which constitute the waste matrix. Therefore, only a few representative measurements are sufficient for such uranium-bearing wastes. Second, it is possible to make theoretical calculations of radon emanation coefficients for uranium-bearing wastes contaminated by UO 2 particles before sintering. In the present study, simulated uranium-bearing wastes contaminated by dissolved uranium were prepared, their radon emanation coefficients were measured and radon emanation coefficients were calculated theoretically for uranium-bearing wastes contaminated by UO 2 particles before sintering. The obtained radon emanation coefficients are distributed at higher values than those for ubiquitous soils and rocks in the natural environment. Therefore, it is not correct to just compare uranium concentrations among uranium-bearing wastes, ubiquitous soils and rocks in terms of radiation exposure. The radon emanation coefficients obtained in the present study have to be employed together with the uranium concentration in uranium-bearing wastes in order to achieve proper assessment of radiation exposure. (author)

Failure of GIMBAL bearing in directional GYRO

International Nuclear Information System (INIS)

Pervaiz, R.; Baig, N.A.; Shahid, M.; Ahmad, A.; Chohan, G.Y.

2003-01-01

This paper relates to the directional gyro of a sensing device used in indigenously developed surface-to-surface missile. The assembling of more than one thousand components in the form of several sub assemblies including hundreds of silver solders of this device was done in the hundred-thousands-class clean room according to assembly procedure. Whereas more than twenty bearings including gimbals bearings were assembled in the ten-thousands-class clean room after inspection/ testing them on beating testing system as per routine. The device was entered in testing and adjustment phase after successful completion of assembly work. The directional gyro qualified all the tests except the most critical one, the drift-rate. The drift-rate of outer gimbal was 60% more than permissible limit whereas drift-rate of inner gimbal was found O.K. It was diagnosed that at least one inner gimbal bearing out of two had some problem. The results were same after rebalancing of gimbals three times. The directional gyro was disassembled in clean room and the radial-thrust-bearing was recovered and flange bearing which are inner gimbal bearings. They were checked on bearing testing system and it was found that flange-bearing had more friction than permissible limit and hence rejected but radial thrust bearing were declared O.K. The gyro was reassembled with new O.K. flange bearing and the assembly work was completed in all respects. The sensing device qualified all the tests including the drift-rate. This case study is being presented to emphasize the importance of careful assembly of gyro in clean environment. (author)

Bearing life in contaminated oil and oil passing into bearing for tapered roller bearing; Ensui koro jikuuke ni okeru ibutsu yuchu deno jumyo to kantsu yuryo

Energy Technology Data Exchange (ETDEWEB)

Asai, Y; Oshima, H; Sakamoto, K [Koyo Seiko Co. Ltd., Osaka (Japan)

1997-10-01

In this paper a relationship between depth of dents, area of dents gathered and bearing life has been investigated for tapered roller bearings used in differential gear case. It is effective for the longer bearing life to reduce hard particles of Fe especially among several contaminations existing in the gear case. It is also effective to make oil level lower in the case from the view point for reduction of number of dents. 8 refs., 8 figs., 4 tabs.

Grizzly bears and mining in the Cheviot region

Energy Technology Data Exchange (ETDEWEB)

Symbaluk, M.; Archibald, T. [Foothills Research Inst., Hinton, AB (Canada)

2008-07-01

This presentation described a grizzly bear research program conducted by the Foothill Research Institute at the Cheviot mine. The research program uses a satellite land classification protocol and remote sensing tools to map and identify the grizzly bear habitat. Modelling is also conducted to predict bear probabilities. Global information systems (GIS) are used to evaluate bear responses to human activities. Grizzly bear health and wellness is also assessed as part of the programs. Land maps are combined with global positioning systems (GPS) and resource selection function (RSF) models in order to map grizzly bear distribution. Data obtained from the program is used to inform decision-making and support policy development. Previous studies predicted that the grizzly bear population would disappear from the Cheviot mine area after 20 years of its being in operation. The research program provided real data to test predictions made during previous environmental assessments. Grizzly bear populations have actually increased in the mining area. It was concluded that the bears have moved more freely through industrial landscapes than previously predicted. tabs., figs.

Treatment of painful diabetic peripheral neuropathy.

Science.gov (United States)

Rosenberg, Casandra J; Watson, James C

2015-02-01

Painful diabetic peripheral neuropathy impairs quality of life and can be difficult to treat. To discuss current treatment recommendations for painful diabetic peripheral neuropathy. Literature review. Systematic review of the literature discussing treatment of painful diabetic peripheral neuropathy. Existing treatment guidelines were studied and compared. Painful diabetic peripheral neuropathy occurs in about one in six people with diabetes. This condition impairs quality of life and increases healthcare costs. Treatment recommendations exist, but individual patient therapy can require a trial-and-error approach. Many treatment options have adjuvant benefits or side effects which should be considered prior to initiating therapy. Often, a combination of treatment modalities with various mechanisms of action is required for adequate pain control. Adequate medication titration and a reasonable trial period should be allowed. The treatment of painful diabetic peripheral neuropathy can be challenging, but effective management can improve patient's quality of life. Painful diabetic peripheral neuropathy impairs quality of life and can be difficult to treat. Many treatment options have adjuvant benefits or side effects which should be considered prior to initiating therapy. Often, a combination of treatment modalities with various mechanisms of action is required for adequate pain control. © The International Society for Prosthetics and Orthotics 2014.

Ball Bearing Analysis with the ORBIS Tool

Science.gov (United States)

Halpin, Jacob D.

2016-01-01

Ball bearing design is critical to the success of aerospace mechanisms. Key bearing performance parameters, such as load capability, stiffness, torque, and life all depend on accurate determination of the internal load distribution. Hence, a good analytical bearing tool that provides both comprehensive capabilities and reliable results becomes a significant asset to the engineer. This paper introduces the ORBIS bearing tool. A discussion of key modeling assumptions and a technical overview is provided. Numerous validation studies and case studies using the ORBIS tool are presented. All results suggest the ORBIS code closely correlates to predictions on bearing internal load distributions, stiffness, deflection and stresses.

Levofloxacin oxidation by ozone and hydroxyl radicals: kinetic study, transformation products and toxicity.

Science.gov (United States)

Hamdi El Najjar, Nasma; Touffet, Arnaud; Deborde, Marie; Journel, Romain; Leitner, Nathalie Karpel Vel

2013-10-01

This work was carried out to investigate the fate of the antibiotic levofloxacin upon oxidation with ozone and hydroxyl radicals. A kinetic study was conducted at 20 °C for each oxidant. Ozonation experiments were performed using a competitive kinetic method with carbamazepin as competitor. Significant levofloxacin removal was observed during ozonation and a rate constant value of 6.0×10(4) M(-1) s(-1) was obtained at pH 7.2. An H2O2/UV system was used for the formation of hydroxyl radicals HO. The rate constant of HO was determined in the presence of a high H2O2 concentration. The kinetic expressions yielded a [Formula: see text] value of 4.5×10(9) M(-1) s(-1) at pH 6.0 and 5.2×10(9) M(-1) s(-1) at pH 7.2. These results were used to develop a model to predict the efficacy of the ozonation process and pharmaceutical removal was estimated under different ozonation conditions (i.e. oxidant concentrations and contact times). The results showed that levofloxacin was completely degraded by molecular ozone during ozonation of water and that hydroxyl radicals had no effect in real waters conditions. Moreover, LC/MS/MS and toxicity assays using Lumistox test were performed to identify ozonation transformation products. Under these conditions, four transformation products were observed and their chemical structures were proposed. The results showed an increase in toxicity during ozonation, even after degradation of all of the observed transformation products. The formation of other transformation products not identified under our experimental conditions could be responsible for the observed toxicity. These products might be ozone-resistant and more toxic to Vibrio fisheri than levofloxacin. Copyright © 2013 Elsevier Ltd. All rights reserved.

Superconducting bearings for flywheel applications

DEFF Research Database (Denmark)

Abrahamsen, A.B.

2001-01-01

A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found onthe applications of superconducting bearings...

Stochasticity in Natural Forage Production Affects Use of Urban Areas by Black Bears: Implications to Management of Human-Bear Conflicts

Science.gov (United States)

Baruch-Mordo, Sharon; Wilson, Kenneth R.; Lewis, David L.; Broderick, John; Mao, Julie S.; Breck, Stewart W.

2014-01-01

The rapid expansion of global urban development is increasing opportunities for wildlife to forage and become dependent on anthropogenic resources. Wildlife using urban areas are often perceived dichotomously as urban or not, with some individuals removed in the belief that dependency on anthropogenic resources is irreversible and can lead to increased human-wildlife conflict. For American black bears (Ursus americanus), little is known about the degree of bear urbanization and its ecological mechanisms to guide the management of human-bear conflicts. Using 6 years of GPS location and activity data from bears in Aspen, Colorado, USA, we evaluated the degree of bear urbanization and the factors that best explained its variations. We estimated space use, activity patterns, survival, and reproduction and modeled their relationship with ecological covariates related to bear characteristics and natural food availability. Space use and activity patterns were dependent on natural food availability (good or poor food years), where bears used higher human density areas and became more nocturnal in poor food years. Patterns were reversible, i.e., individuals using urban areas in poor food years used wildland areas in subsequent good food years. While reproductive output was similar across years, survival was lower in poor food years when bears used urban areas to a greater extent. Our findings suggest that bear use of urban areas is reversible and fluctuates with the availability of natural food resources, and that removal of urban individuals in times of food failures has the potential to negatively affect bear populations. Given that under current predictions urbanization is expected to increase by 11% across American black bear range, and that natural food failure years are expected to increase in frequency with global climate change, alternative methods of reducing urban human-bear conflict are required if the goal is to prevent urban areas from becoming population sinks

Stochasticity in natural forage production affects use of urban areas by black bears: implications to management of human-bear conflicts.

Directory of Open Access Journals (Sweden)

Sharon Baruch-Mordo

Full Text Available The rapid expansion of global urban development is increasing opportunities for wildlife to forage and become dependent on anthropogenic resources. Wildlife using urban areas are often perceived dichotomously as urban or not, with some individuals removed in the belief that dependency on anthropogenic resources is irreversible and can lead to increased human-wildlife conflict. For American black bears (Ursus americanus, little is known about the degree of bear urbanization and its ecological mechanisms to guide the management of human-bear conflicts. Using 6 years of GPS location and activity data from bears in Aspen, Colorado, USA, we evaluated the degree of bear urbanization and the factors that best explained its variations. We estimated space use, activity patterns, survival, and reproduction and modeled their relationship with ecological covariates related to bear characteristics and natural food availability. Space use and activity patterns were dependent on natural food availability (good or poor food years, where bears used higher human density areas and became more nocturnal in poor food years. Patterns were reversible, i.e., individuals using urban areas in poor food years used wildland areas in subsequent good food years. While reproductive output was similar across years, survival was lower in poor food years when bears used urban areas to a greater extent. Our findings suggest that bear use of urban areas is reversible and fluctuates with the availability of natural food resources, and that removal of urban individuals in times of food failures has the potential to negatively affect bear populations. Given that under current predictions urbanization is expected to increase by 11% across American black bear range, and that natural food failure years are expected to increase in frequency with global climate change, alternative methods of reducing urban human-bear conflict are required if the goal is to prevent urban areas from

Stochasticity in natural forage production affects use of urban areas by black bears: implications to management of human-bear conflicts.

Science.gov (United States)

Baruch-Mordo, Sharon; Wilson, Kenneth R; Lewis, David L; Broderick, John; Mao, Julie S; Breck, Stewart W

2014-01-01

The rapid expansion of global urban development is increasing opportunities for wildlife to forage and become dependent on anthropogenic resources. Wildlife using urban areas are often perceived dichotomously as urban or not, with some individuals removed in the belief that dependency on anthropogenic resources is irreversible and can lead to increased human-wildlife conflict. For American black bears (Ursus americanus), little is known about the degree of bear urbanization and its ecological mechanisms to guide the management of human-bear conflicts. Using 6 years of GPS location and activity data from bears in Aspen, Colorado, USA, we evaluated the degree of bear urbanization and the factors that best explained its variations. We estimated space use, activity patterns, survival, and reproduction and modeled their relationship with ecological covariates related to bear characteristics and natural food availability. Space use and activity patterns were dependent on natural food availability (good or poor food years), where bears used higher human density areas and became more nocturnal in poor food years. Patterns were reversible, i.e., individuals using urban areas in poor food years used wildland areas in subsequent good food years. While reproductive output was similar across years, survival was lower in poor food years when bears used urban areas to a greater extent. Our findings suggest that bear use of urban areas is reversible and fluctuates with the availability of natural food resources, and that removal of urban individuals in times of food failures has the potential to negatively affect bear populations. Given that under current predictions urbanization is expected to increase by 11% across American black bear range, and that natural food failure years are expected to increase in frequency with global climate change, alternative methods of reducing urban human-bear conflict are required if the goal is to prevent urban areas from becoming population sinks.

Promoting peripheral myelin repair.

Science.gov (United States)

Zhou, Ye; Notterpek, Lucia

2016-09-01

Compared to the central nervous system (CNS), peripheral nerves have a remarkable ability to regenerate and remyelinate. This regenerative capacity to a large extent is dependent on and supported by Schwann cells, the myelin-forming glial cells of the peripheral nervous system (PNS). In a variety of paradigms, Schwann cells are critical in the removal of the degenerated tissue, which is followed by remyelination of newly-regenerated axons. This unique plasticity of Schwann cells has been the target of myelin repair strategies in acute injuries and chronic diseases, such as hereditary demyelinating neuropathies. In one approach, the endogenous regenerative capacity of Schwann cells is enhanced through interventions such as exercise, electrical stimulation or pharmacological means. Alternatively, Schwann cells derived from healthy nerves, or engineered from different tissue sources have been transplanted into the PNS to support remyelination. These transplant approaches can then be further enhanced by exercise and/or electrical stimulation, as well as by the inclusion of biomaterial engineered to support glial cell viability and neurite extension. Advances in our basic understanding of peripheral nerve biology, as well as biomaterial engineering, will further improve the functional repair of myelinated peripheral nerves. Copyright © 2016 Elsevier Inc. All rights reserved.

Characterization and measurement of hybrid gas journal bearings

Science.gov (United States)

Lawrence, Tom Marquis

This thesis concentrates on the study of hybrid gas journal bearings (bearings with externally pressurized mass addition). It differs from most work in that it goes back to "basics" to explore the hydrodynamic phenomena in the bearing gap. The thesis compares geometrically identical bearings with 2 configurations of external pressurization, porous liners where mass-addition compensation is varied by varying the liner's permeability, and bushings with 2 rows of 6 feedholes where the mass-addition compensation is varied by the feedhole diameter. Experimentally, prototype bearings with mass-addition compensation that spans 2 orders of magnitude with differing clearances are built and their aerostatic properties and mass addition characteristics are thoroughly tested. The fundamental equations for compressible, laminar, Poiseuille flow are used to suggest how the mass flow "compensation" should be mathematically modeled. This is back-checked against the experimental mass flow measurements and is used to determine a mass-addition compensation parameter (called Kmeas) for each prototype bushing. In so doing, the methodology of modeling and measuring the mass addition in a hybrid gas bearing is re-examined and an innovative, practical, and simple method is found that makes it possible to make an "apples-to-apples" comparison between different configurations of external pressurization. This mass addition model is used in conjunction with the Reynolds equation to perform theory-based numerical analysis of virtual hybrid gas journal bearings (CFD experiments). The first CFD experiments performed use virtual bearings modeled to be identical to the experimental prototypes and replicate the experimental work. The results are compared and the CFD model is validated. The ontological significance of appropriate dimensionless similitude parameters is re-examined and a, previously lacking, complete set of similitude factors is found for hybrid bearings. A new practical method is

Peripheral neuropathy in HIV: prevalence and risk factors

Science.gov (United States)

Evans, Scott R.; Ellis, Ronald J.; Chen, Huichao; Yeh, Tzu-min; Lee, Anthony J.; Schifitto, Giovanni; Wu, Kunling; Bosch, Ronald J.; McArthur, Justin C.; Simpson, David M.; Clifford, David B.

2011-01-01

Objectives To estimate neuropathic sign/symptom rates with initiation of combination antiretroviral therapy (cART) in HIV-infected ART-naive patients, and to investigate risk factors for: peripheral neuropathy and symptomatic peripheral neuropathy (SPN), recovery from peripheral neuropathy/SPN after neurotoxic ART (nART) discontinuation, and the absence of peripheral neuropathy/SPN while on nART. Design AIDS Clinical Trials Group (ACTG) Longitudinal Linked Randomized Trial participants who initiated cART in randomized trials for ART-naive patients were annually screened for symptoms/signs of peripheral neuropathy. ART use and disease characteristics were collected longitudinally. Methods Peripheral neuropathy was defined as at least mild loss of vibration sensation in both great toes or absent/hypoactive ankle reflexes bilaterally. SPN was defined as peripheral neuropathy and bilateral symptoms. Generalized estimating equation logistic regression was used to estimate associations. Results Two thousand, one hundred and forty-one participants were followed from January 2000 to June 2007. Rates of peripheral neuropathy/SPN at 3 years were 32.1/8.6% despite 87.1% with HIV-1RNA 400 copies/ml or less and 70.3% with CD4 greater than 350 cells/µl. Associations with higher odds of peripheral neuropathy included older patient age and current nART use. Associations with higher odds of SPN included older patient age, nART use, and history of diabetes mellitus. Associations with lower odds of recovery after nART discontinuation included older patient age. Associations with higher odds of peripheral neuropathy while on nART included older patient age and current protease inhibitor use. Associations with higher odds of SPN while on nART included older patient age, history of diabetes, taller height, and protease inhibitor use. Conclusion Signs of peripheral neuropathy remain despite virologic/immunologic control but frequently occurs without symptoms. Aging is a risk factor for

Experiments and simulations of NOx formation in the combustion of hydroxylated fuels

KAUST Repository

Bohon, Myles

2015-06-01

This work investigates the influence of molecular structure in hydroxylated fuels (i.e. fuels with one or more hydroxyl groups), such as alcohols and polyols, on NOx formation. The fuels studied are three lower alcohols (methanol, ethanol, and n-propanol), two diols (1,2-ethanediol and 1,2-propanediol), and one triol (1,2,3-propanetriol); all of which are liquids at room temperature and span a wide range of thermophysical properties. Experimental stack emissions measurements of NO/NO2, CO, and CO2 and flame temperature profiles utilizing a rake of thermocouples were obtained in globally lean, swirling, liquid atomized spray flames inside a refractory-lined combustion chamber as a function of the atomizing air flow rate and swirl number. These experiments show significantly lower NOx formation with increasing fuel oxygen content despite similarities in the flame temperature profiles. By controlling the temperature profiles, the contribution to NOx formation through the thermal mechanism were matched, and variations in the contribution through non-thermal NOx formation pathways are observed. Simulations in a perfectly stirred reactor, at conditions representative of those measured within the combustion region, were conducted as a function of temperature and equivalence ratio. The simulations employed a detailed high temperature chemical kinetic model for NOx formation from hydroxylated fuels developed based on recent alcohol combustion models and extended to include polyol combustion chemistry. These simulations provide a qualitative comparison to the range of temperatures and equivalence ratios observed in complex swirling flows and provide insight into the influence of variations in the fuel decomposition pathways on NOx formation. It is observed that increasing the fuel bound oxygen concentration ultimately reduces the formation of NOx by increasing the proportion of fuel oxidized through formaldehyde, as opposed to acetylene or acetaldehyde. The subsequent

Peripheral Vestibular System Disease in Vestibular Schwannomas

DEFF Research Database (Denmark)

Møller, Martin Nue; Hansen, Søren; Caye-Thomasen, Per

2015-01-01

density of the peripheral vestibular nerve branches, and atrophy of the neuroepithelium of the vestibular end organs. In cases with small tumors, peripheral disease occurred only in the tissue structures innervated by the specific nerve from which the tumor originated. CONCLUSION: Vestibular schwannomas...... are associated with distinctive disease of the peripheral vestibular tissue structures, suggesting anterograde degeneration and that dizziness in these patients may be caused by deficient peripheral vestibular nerve fibers, neurons, and end organs. In smaller tumors, a highly localized disease occurs, which...

Assessing bear-human conflicts in the Yukon Territory

OpenAIRE

Lukie, Raechel Dawn

2010-01-01

Managing conflicts between bears and humans is vital for human safety and for the conservation of bears. This study investigated black bear (Ursus americanus) and grizzly bear (Ursus arctos) interactions with humans in 18 major communities of the Yukon Territory. I used an information theoretic approach to generate predictive models of the relative potential of bear-human interaction for the 9 conservation officer management regions in the Yukon Territory. I independently modeled interactions...

77 FR 77070 - Black Bear Hydro Partners, LLC;

Science.gov (United States)

2012-12-31

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 2727-086] Black Bear Hydro...: October 24, 2012. d. Submitted By: Black Bear Hydro Partners, LLC (Black Bear Hydro). e. Name of Project... designating Black Bear Hydro as the Commission's non-federal representative for carrying out informal...

DNA radiolysis in DNA-protein complex: a stochastic simulation of attack by hydroxyl radicals

Czech Academy of Sciences Publication Activity Database

Běgusová, Marie; Giliberto, S.; Gras, J.; Sy, D.; Charlier, M.; Spotheim Maurizot, M.

2003-01-01

Roč. 79, č. 6 (2003), s. 385-391 ISSN 0955-3002 R&D Projects: GA AV ČR IAA1048103 Institutional research plan: CEZ:AV0Z1048901 Keywords : radiolysis * DNA-protein complexes * hydroxyl radicals Subject RIV: BO - Biophysics Impact factor: 2.165, year: 2003

[Imiquimod combined with dendritic cell vaccine decreases Treg proportion and enhances anti-tumor responses in mice bearing melanoma].

Science.gov (United States)

Ren, Shurong; Wang, Qiubo; Zhang, Yanli; Lu, Cuixiu; Li, Ping; Li, Yumei

2017-02-01

Objective To investigate the therapeutic effect of Toll-like receptor 7 (TLR7) agonist imiquimod combined with dendritic cell (DC)-based tumor vaccine on melanoma in mice and the potential mechanism. Methods Melanoma-bearing mouse models were established by subcutanous injection of B16-OVA cells into C57BL/6 mice. DCs were isolated from mouse bone marrow and propagated in culture medium with recombinant mouse granulocyte-macrophage colony-stimulating factor (rmGM-CSF) and recombinant mouse interleukin-4 (rmIL-4). DC vaccine (OVA-DC) was prepared by overnight incubation of DCs added with chicken ovalbumin. C57BL/6 mice were separated into four groups which were treated with PBS, topical imiquimod application, OVA-DC intradermal injection and imiquimod plus OVA-DC, respectively. The tumor size was calculated by digital vernier caliper. Peripheral blood CD4 + FOXP3 + Tregs of the tumor-bearing mice was detected by flow cytometry. The cytotoxicity of splenic lymphocyte against B16-OVA was assessed in vitro by CCK-8 assay. Results Compared with the other three groups, B16-OVA-bearing mice treated with imiquimod plus DC vaccine had the smallest tumor volume. The percentage of CD4 + FOXP3 + Tregs decreased significantly in the combined treated mice. The combined treatment enhanced significantly cytotoxicity of splenic lymphocytes against B16-OVA cells. Conclusion Imiquimod combined with antigen-pulsed-DC vaccine could reduce CD4 + FOXP3 + Treg proportion and promote anti-tumor effect in mice with melanoma.

Effects of exotic species on Yellowstone's grizzly bears

Science.gov (United States)

Reinhart, Daniel P.; Haroldson, Mark A.; Mattson, D.J.; Gunther, Kerry A.

2001-01-01

Humans have affected grizzly bears (Ursus arctos horribilis) by direct mortality, competition for space and resources, and introduction of exotic species. Exotic organisms that have affected grizzly bears in the Greater Yellowstone Area include common dandelion (Taraxacum officinale), nonnative clovers (Trifolium spp.), domesticated livestock, bovine brucellosis (Brucella abortus), lake trout (Salvelinus namaycush), and white pine blister rust (Cronartium ribicola). Some bears consume substantial amounts of dandelion and clover. However, these exotic foods provide little digested energy compared to higher-quality bear foods. Domestic livestock are of greater energetic value, but use of this food by bears often leads to conflicts with humans and subsequent increases in bear mortality. Lake trout, blister rust, and brucellosis diminish grizzly bears foods. Lake trout prey on native cutthroat trout (Oncorhynchus clarkii) in Yellowstone Lake; white pine blister rust has the potential to destroy native whitebark pine (Pinus albicaulis) stands; and management response to bovine brucellosis, a disease found in the Yellowstone bison (Bison bison) and elk (Cervus elaphus), could reduce populations of these 2 species. Exotic species will likely cause more harm than good for Yellowstone grizzly bears. Managers have few options to mitigate or contain the impacts of exotics on Yellowstone's grizzly bears. Moreover, their potential negative impacts have only begun to unfold. Exotic species may lead to the loss of substantial highquality grizzly bear foods, including much of the bison, trout, and pine seeds that Yellowstone grizzly bears currently depend upon.

Effect of rb-bFGF eye drops and hydroxyl indican eye drops on tear film stability and dry eye symptoms after age-related cataract surgery

Directory of Open Access Journals (Sweden)

Jing Chen

2017-10-01

Full Text Available AIM: To compare and analyze the effect of recombinant bovine basic fibroblast growth factor(bFGFeye drops and hydroxyl indican eye drops on the tear film stability and dry eye symptoms after age-related cataract surgery. METHODS: A total of 115 patients(115 affected eyeswith dry eyes after age-related cataract surgery were divided into the bFGF group, the hydroxyl indican group and the blank control group by the random number table method. The blank control group was only given routine anti-inflammatory treatment, and on the basis, the bFGF group and the hydroxyl indican group were treated with bFGF eye drops and hydroxyl indican eye drops respectively. The clinical efficacy, adverse reactions, changes in scores of dry eye symptoms, Schirmer test(SⅠt, tear film break-up time(BUTand corneal fluorescein staining(CFSscores at different time points were compared among the three groups. RESULTS: The total markedly effective rates in the bFGF group(89.5%was higher than that in the hydroxyl indican group(70.3%or the blank control group(47.5%(PPPCONCLUSION: The tear film is unstable in early stage after age-related cataract surgery, and there are dry eye symptoms. The intervention with bFGF eye drops and hydroxyl indican eye drops can effectively restore the tear film stability and significantly relieve dry eye symptoms, and the effect of bFGF eye drops is more significant.

Unusual spin-trap chemistry for the reaction of hydroxyl radical with the carcinogen N-nitrosodimethylamine

Science.gov (United States)

Wink, David A.; Desrosiers, Marc F.

The reaction of the potent carcinogen N-nitrosodimethylamine (NDMA) with hydroxyl radical generated via radiolysis was studied using EPR techniques. Attempts to spin trap NDMA radical intermediates with 3,5-dibromo-4-nitrosobenzene sulfonate (DBNBS) produced only unusual DBNBS radicals. One of these radicals was shown to be generated by both reaction of DBNBS with nitric oxide, and direct oxidation of DBNBS with an inorganic oxidant ( .Br -2). Another DBNBS radical was identified as a sulfite spin adduct resulting from the degradation of DBNBS by a NDMA reactive intermediate. In the absence of DBNBS, hydroxyl radical reaction with NDMA gave the dimethylnitroxide radical. Unexpectedly, addition of DBNBS to a solution containing dimethylnitroxide produced an EPR spectrum nearly identical to that of NDMA solutions with DBNBS added before radiolysis. A proposed mechanism accounting for these observations is presented.

Study of the hydroxyl radical: Experimental advances in microwave spectroscopy, theoretical model and astrophysical consequences

International Nuclear Information System (INIS)

Destombes, Jean-Luc

1978-01-01

This research thesis mainly addresses the experimental and theoretical study of the hydroxyl radical, and the consequences of the obtained results in astrophysics which are studied with a model of pumping by the far infrared. After a recall of notions related to microwave spectroscopy and to molecular radio-astronomy, the author more particularly discusses different aspects of microwave spectroscopy in the interstellar environment and in laboratory. He also reviews different types of spectrometers for unsteady molecules. In the second part, he addresses issues related to the hydroxyl radical (OH): presentation of spectrometers, study of the reaction environment, study of the radical microwave spectrum, identification of transitions by frequency measurements. In the last parts, the author addresses some aspects of interstellar OH masers, and reports the application of some results to simple models of pumping by the far infra red

Research In Diagnosing Bearing Defects From Vibrations

Science.gov (United States)

Zoladz, T.; Earhart, E.; Fiorucci, T.

1995-01-01

Report describes research in bearing-defect signature analysis - use of vibration-signal analysis to diagnose defects in roller and ball bearings. Experiments performed on bearings in good condition and other bearings in which various parts scratched to provide known defects correlated with vibration signals. Experiments performed on highly instrumented motor-driven rotor assembly at speeds up to 10,050 r/min, using accelerometers, velocity probes, and proximity sensors mounted at various locations on assembly to measure vibrations.

The Biotribology of PEEK-on-HXLPE Bearings Is Comparable to Traditional Bearings on a Multidirectional Pin-on-disk Tester.

Science.gov (United States)

Baykal, Doruk; Siskey, Ryan S; Underwood, Richard J; Briscoe, Adam; Kurtz, Steven M

2016-11-01

All-polymer bearings involving polyetheretherketone (PEEK) have been proposed for orthopaedic applications because they may reduce stress shielding, reduce weight of the implants, reduce wear and risk of osteolysis, and prevent release of metal ions by replacing the metal articulating components. Little is known about the biotribology of all-polymer PEEK bearings, including the effects of cross-shear, which are relevant for implant longevity, especially in the hip, and increased temperature that may affect lubricant proteins and, hence, lubrication in the joint. Using pin-on-disk in vitro testing, we asked: (1) Can all-polymer bearing couples involving PEEK have a comparable or lower wear rate than highly crosslinked UHMWPE (HXLPE) on CoCr bearing couples? (2) Is the wear rate of PEEK bearing couples affected by the amount of cross-shear? (3) Is there a difference in wear mechanism and surface morphology for all-polymer bearing surfaces compared with UHMWPE (HXLPE) on CoCr? We simultaneously tested a total of 100 pin-on-disk couples (n = 10 per bearing couple) consisting of three traditional metal-on-UHMWPE and seven polymer-on-polymer bearings for 2 million cycles under physiologically relevant conditions and in accordance with ASTM F732. Using analysis of variance, we analyzed the effect of bearing surface topography and cross-shear on wear rate. The changes in surface topography were evaluated using optical microscopy. Sample size was sufficient to provide 80% power to detect a difference of 1.4 mm 3 /MC in average wear rates of bearing couples. The combined wear rates of all-polymer bearing couples were not different than traditional bearing couples. With the numbers available, the PEEK and HXLPE bearing couple had a mean wear rate (WR: mean ± SD) of 0.9 ± 1.1 mm 3 /MC (95% confidence interval [CI], 0.2-1.5 mm 3 /MC), which was not different than the wear rate of the CoCr and HXLPE bearing couple (1.6 ± 2.0 mm 3 /MC; 95% CI, 0.4-2.8 mm 3 /MC; mean difference

Bearing assemblies, apparatuses, and motor assemblies using the same

Science.gov (United States)

Sexton, Timothy N.; Cooley, Craig H.; Knuteson, Cody W.

2015-12-29

Various embodiments of the invention relate to bearing assemblies, apparatuses and motor assemblies that include geometric features configured to impart a selected amount of heat transfer and/or hydrodynamic film formation. In an embodiment, a bearing assembly may include a plurality of superhard bearing pads distributed circumferentially about an axis. At least some of the plurality of superhard bearing pads may include a plurality of sub-superhard bearing elements defining a bearing surface. At least some of the plurality of sub-superhard bearing elements may be spaced from one another by one or more voids to impart a selected amount of heat transfer and hydrodynamic film formation thereon during operation. The bearing assembly may also include a support ring that carries the plurality of superhard bearing pads. In addition, at least a portion of the sub-superhard bearing elements may extend beyond the support ring.

Vertically loaded pivot bearing for high-speed shafts

International Nuclear Information System (INIS)

Zippe, G.; Werner, D.; Keller, A.; Stephan, E.

1974-01-01

The pivot bearing subjected to vertical loads has a pivot with a rounded end and a diametral slot and a cup-shaped recess in the bearing box. The end of the pivot and the recess constitute a gap which widens towards the periphery of the bearing. The bearing box carries an attachment with a clearance, the shape of a hollow cylinder and accomodating the pivot and its shaft. To feed the lubricating oil surrounding and filling the bearing there is a groove either in the wall of the clearance or at the end of the pivot in the direction of rotation of the shaft or against it. The oil carried to the support point flows back into the oil bath surrounding the bearing through a slot in the bearing box. (DG) [de

Non-Weight-Bearing and Weight-Bearing Ultrasonography of Select Foot Muscles in Young, Asymptomatic Participants: A Descriptive and Reliability Study.

Science.gov (United States)

Battaglia, Patrick J; Mattox, Ross; Winchester, Brett; Kettner, Norman W

The primary aim of this study was to determine the reliability of diagnostic ultrasound imaging for select intrinsic foot muscles using both non-weight-bearing and weight-bearing postures. Our secondary aim was to describe the change in muscle cross-sectional area (CSA) and dorsoplantar thickness when bearing weight. An ultrasound examination was performed with a linear ultrasound transducer operating between 9 and 12 MHz. Long-axis and short-axis ultrasound images of the abductor hallucis, flexor digitorum brevis, and quadratus plantae were obtained in both the non-weight-bearing and weight-bearing postures. Two examiners independently collected ultrasound images to allow for interexaminer and intraexaminer reliability calculation. The change in muscle CSA and dorsoplantar thickness when bearing weight was also studied. There were 26 participants (17 female) with a mean age of 25.5 ± 3.8 years and a mean body mass index of 28.0 ± 7.8 kg/m 2 . Inter-examiner reliability was excellent when measuring the muscles in short axis (intraclass correlation coefficient >0.75) and fair to good in long axis (intraclass correlation coefficient >0.4). Intraexaminer reliability was excellent for the abductor hallucis and flexor digitorum brevis and ranged from fair to good to excellent for the quadratus plantae. Bearing weight did not reduce interexaminer or intraexaminer reliability. All muscles exhibited a significant increase in CSA when bearing weight. This is the first report to describe weight-bearing diagnostic ultrasound of the intrinsic foot muscles. Ultrasound imaging is reliable when imaging these muscles bearing weight. Furthermore, muscle CSA increases in the weight-bearing posture. Copyright © 2016. Published by Elsevier Inc.

Eastern slopes grizzly bear project : project update

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-01-01

This report updates a study to examine the cumulative effects of human activities on the grizzly bears in the central Canadian Rockies. The project was initiated in 1994 to acquire accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of the study is used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers monitored 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers worked with representatives from Husky Oil and Rigel Energy on the development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over eight years indicates that the grizzly bears have few and infrequent offspring. Using the information gathered thus far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears suffer from high mortality, and the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The research concluded in November 2001 provides sufficient information to accurately asses the status of the grizzly bear population and habitat. The data will be analyzed and integrated in 2002 into models that reflect the variables affecting grizzly bears and a final report will be published.

Nonlinear Dynamic Response of Compliant Journal Bearings

Directory of Open Access Journals (Sweden)

Glavatskih S.

2012-07-01

Full Text Available This paper investigates the dynamic response of the compliant tilting pad journal bearings subjected to synchronous excitation. Bearing compliance is affected by the properties of pad liner and pad support geometry. Different unbalance eccentricities are considered. It is shown that bearing dynamic response is non-linear. Journal orbit complexity increases with pad compliance though the orbit amplitudes are marginally affected at low loads. At high loads, the journal is forced to operate outside the bearing clearance. The polymer liner reduces the maximum oil film pressure by a factor of 2 when compared to the white metal liner. The nonlinear dynamic response of compliant tilting pad journal bearings is thoroughly discussed.

New model system for testing effects of flavonoids on doxorubicin-related formation of hydroxyl radicals

Czech Academy of Sciences Publication Activity Database

Souček, P.; Kondrová, E.; Heřmánek, J.; Stopka, Pavel; Boumendjel, A.; Ueng, YF.; Gut, I.

2011-01-01

Roč. 22, č. 2 (2011), s. 176-184 ISSN 0959-4973 Institutional research plan: CEZ:AV0Z40320502 Keywords : doxorubicin * electron spin resonance * flavonoids hydroxyl radicals Subject RIV: FD - Oncology ; Hematology Impact factor: 2.407, year: 2011

Grizzly bear density in Glacier National Park, Montana

Science.gov (United States)

Kendall, K.C.; Stetz, J.B.; Roon, David A.; Waits, L.P.; Boulanger, J.B.; Paetkau, David

2008-01-01

We present the first rigorous estimate of grizzly bear (Ursus arctos) population density and distribution in and around Glacier National Park (GNP), Montana, USA. We used genetic analysis to identify individual bears from hair samples collected via 2 concurrent sampling methods: 1) systematically distributed, baited, barbed-wire hair traps and 2) unbaited bear rub trees found along trails. We used Huggins closed mixture models in Program MARK to estimate total population size and developed a method to account for heterogeneity caused by unequal access to rub trees. We corrected our estimate for lack of geographic closure using a new method that utilizes information from radiocollared bears and the distribution of bears captured with DNA sampling. Adjusted for closure, the average number of grizzly bears in our study area was 240.7 (95% CI = 202–303) in 1998 and 240.6 (95% CI = 205–304) in 2000. Average grizzly bear density was 30 bears/1,000 km2, with 2.4 times more bears detected per hair trap inside than outside GNP. We provide baseline information important for managing one of the few remaining populations of grizzlies in the contiguous United States.

Research on Bored Bearing Characteristics in Xi’an

Directory of Open Access Journals (Sweden)

Zhang Lipeng

2015-01-01

Full Text Available To analyze the influence of different soil properties on pile foundation load-bearing characteristics, taking a section of railway in Xi’an and a bridge of Xi’an as test area, and by field static load test to study load transfer characteristics after the test piles under axial pressure, including the distribution of axial force, pile lateral friction, tip resistance traits, ultimate bearing capacity determine, and compare with the theory bearing capacity. Experimental results show that, adjacent soil properties change large, axial force and lateral friction mutation at the junction of corresponding soil layer. Silty clay in different parts is below ground, and its lateral friction plays much difference. Pile lateral friction plays an important role in bearing capacity, but the role of round gravel soil end bearing capacity to pile bearing capacity can’t be ignored. Tests calculate pile bearing capacity significantly larger than standardized formula calculation bearing capacity, which are respectively 55.35% and 119.1%. And give the similar project condition the suggested values of pile bearing capacity and soil friction, to provide reference for similar pile foundation design.

On the future of controllable fluid film bearings

DEFF Research Database (Denmark)

Santos, Ilmar

2011-01-01

lubrication regimes, i.e., as tilting-pad journal bearings, multi-recess journal bearings and plain journal bearings. After a comprehensive overview of the theoretical and experimental technological advancements achieved in university laboratories, the feasibility of industrial applications is highlighted......This work gives an overview of the theoretical and experimental achievements of mechatronics applied to fluid film bearings. Compressible and uncompressible fluids are addressed. Rigid and elastic (deformable) bearing profiles are investigated. Hydraulic, pneumatic, magnetic and piezoelectric...

The photophysical and photochemical properties of new unmetallated and metallated phthalocyanines bearing four 5-chloroquinolin-8-yloxy substituents on peripheral sites

Energy Technology Data Exchange (ETDEWEB)

Nas, Asiye; Demirbaş, Ümit [Department of Chemistry, Karadeniz Technical University, 61080 Trabzon (Turkey); Pişkin, Mehmet [Marmara University, Faculty of Art and Science, Department of Chemistry, 34722 Kadıkoy-Istanbul (Turkey); Durmuş, Mahmut [Gebze Institute of Technology, Department of Chemistry, PO Box 141, Gebze, 41400 Kocaeli (Turkey); Kantekin, Halit, E-mail: halit@ktu.edu.tr [Department of Chemistry, Karadeniz Technical University, 61080 Trabzon (Turkey)

2014-01-15

The synthesis and characterization of novel peripherally tetrakis-(5-chloroquinolin-8-yloxy) substituted metal-free (4), zinc(II) (5), lead(II) (6), cobalt(II) (7), copper(II) (8) and nickel(II) (9) phthalocyanines are described for the first time in this study. The spectroscopic, photophysical (fluorescence quantum yields and lifetimes) and photochemical properties (singlet oxygen production and photodegradation under light irradiation) of metal-free (4), zinc(II) (5) and lead(II) (6) phthalocyanines are investigated in N,N-dimetilformamid (DMF). The newly synthesized cobalt(II) (7), copper(II) (8) and nickel(II) (9) phthalocyanine compounds were not evaluated for this purpose due to open shell nature of these central metals in the phthalocyanine cavity. The influence of various the nature of the central metal ion (zinc, lead or without metal) on these properties has also been investigated and compared. -- Highlights: • The synthesis and characterization of novel peripherally tetrakis-(5-chloroquinolin-8-yloxy) substituted metal-free (4), zinc(II) (5), lead(II) (6), cobalt(II) (7), copper(II) (8) and nickel(II) (9) phthalocyanines. • The spectroscopic, photophysical (fluorescence quantum yields and lifetimes) and photochemical properties of metal-free (4), zinc(II) (5) and lead(II) (6)phthalocyanines in N, N-dimetilformamid (DMF). • The influence of various the nature of the central metal ion (zinc, lead or without metal) on these properties.

Factors affecting hydrogen-tunneling contribution in hydroxylation reactions promoted by oxoiron(IV) porphyrin π-cation radical complexes.

Science.gov (United States)

Cong, Zhiqi; Kinemuchi, Haruki; Kurahashi, Takuya; Fujii, Hiroshi

2014-10-06

Hydrogen atom transfer with a tunneling effect (H-tunneling) has been proposed to be involved in aliphatic hydroxylation reactions catalyzed by cytochrome P450 and synthetic heme complexes as a result of the observation of large hydrogen/deuterium kinetic isotope effects (KIEs). In the present work, we investigate the factors controlling the H-tunneling contribution to the H-transfer process in hydroxylation reaction by examining the kinetics of hydroxylation reactions at the benzylic positions of xanthene and 1,2,3,4-tetrahydronaphthalene by oxoiron(IV) 5,10,15,20-tetramesitylporphyrin π-cation radical complexes ((TMP(+•))Fe(IV)O(L)) under single-turnover conditions. The Arrhenius plots for these hydroxylation reactions of H-isotopomers have upwardly concave profiles. The Arrhenius plots of D-isotopomers, clear isosbestic points, and product analysis rule out the participation of thermally dependent other reaction processes in the concave profiles. These results provide evidence for the involvement of H-tunneling in the rate-limiting H-transfer process. These profiles are simulated using an equation derived from Bell's tunneling model. The temperature dependence of the KIE values (k(H)/k(D)) determined for these reactions indicates that the KIE value increases as the reaction temperature becomes lower, the bond dissociation energy (BDE) of the C-H bond of a substrate becomes higher, and the reactivity of (TMP(+•))Fe(IV)O(L) decreases. In addition, we found correlation of the slope of the ln(k(H)/k(D)) - 1/T plot and the bond strengths of the Fe═O bond of (TMP(+•))Fe(IV)O(L) estimated from resonance Raman spectroscopy. These observations indicate that these factors modulate the extent of the H-tunneling contribution by modulating the ratio of the height and thickness of the reaction barrier.

Superconducting bearings for flywheel applications

Energy Technology Data Exchange (ETDEWEB)

Abrahamsen, Asger Bech

2001-05-01

A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found on the applications of superconducting bearings in flywheels. (au)

Wear numbers for ball cup and journal bearings

NARCIS (Netherlands)

Ligterink, D.J.; Moes, H.

1980-01-01

A wear number is defined for ball cup bearings and for journal bearings where the cup and the cylindrical bearing are made of soft material. This dimensionless wear number provides a relation between the following five quantities: the radius of the ball or the length of the journal bearing in

Hypothyroidism: Can It Cause Peripheral Neuropathy?

Science.gov (United States)

Hypothyroidism: Can it cause peripheral neuropathy? Can hypothyroidism cause peripheral neuropathy and, if so, how is it treated? Answers from Todd B. Nippoldt, M.D. Hypothyroidism — a condition in which your ...

Comparison of High-Flexion Fixed-Bearing and High-Flexion Mobile-Bearing Total Knee Arthroplasties-A Prospective Randomized Study.

Science.gov (United States)

Kim, Young-Hoo; Park, Jang-Won; Kim, Jun-Shik

2018-01-01

There is none, to our knowledge, about comparison of high-flexion fixed-bearing and high-flexion mobile-bearing total knee arthroplasties (TKAs) in the same patients. The purpose of this study was to determine whether clinical results; radiographic and computed tomographic scan results; and the survival rate of a high-flexion mobile-bearing TKA is better than that of a high-flexion fixed-bearing TKA. The present study consisted of 92 patients (184 knees) who underwent same-day bilateral TKA. Of those, 17 were men and 75 were women. The mean age at the time of index arthroplasty was 61.5 ± 8.3 years (range 52-65 years). The mean body mass index was 26.2 ± 3.3 kg/m 2 (range 23-34 kg/m 2 ). The mean follow-up was 11.2 years (range 10-12 years). The Knee Society knee scores (93 vs 92 points; P = .531) and function scores (80 vs 80 points; P = 1.000), WOMAC scores (14 vs 15 points; P = .972), and UCLA activity scores (6 vs 6 points; P = 1.000) were not different between the 2 groups at 12 years follow-up. There were no differences in any radiographic and CT scan parameters between the 2 groups. Kaplan-Meier survivorship of the TKA component was 98% (95% confidence interval, 93-100) in the high-flexion fixed-bearing TKA group and 99% (95% confidence interval, 94-100) in the high-flexion mobile-bearing TKA group 12 years after the operation. We found no benefit to mobile-bearing TKA in terms of pain, function, radiographic and CT scan results, and survivorship. Longer-term follow-up is necessary to prove the benefit of the high-flexion mobile-bearing TKA over the high-flexion fixed-bearing TKA. Copyright © 2017 Elsevier Inc. All rights reserved.

Metabolism of diclofenac in plants--hydroxylation is followed by glucose conjugation.

Science.gov (United States)

Huber, Christian; Bartha, Bernadett; Schröder, Peter

2012-12-01

Pharmaceuticals from human or veterinary medication form a new class of micropollutants that poses a serious threat to our aquatic environment and its organisms. The intensively used nonsteroidal anti-inflammatory drug diclofenac is found in the environment worldwide due to its poor elimination during waste water treatment processes. In order to test phytoremediation as a tool for the removal of this drug from waste water, the uptake of the compound into plant tissues and its metabolic pathway was addressed using Hordeum vulgare (barley) and a hairy root cell culture of Armoracia rusticana (horse radish) as model species. Diclofenac is taken up by plants and undergoes rapid metabolization; already after 3h of exposure the drug and its metabolites could be detected in the plant tissues. Similar to its fate in mammalian cells the drug is activated in a phase I reaction resulting in the hydroxylated metabolite 4'OH-diclofenac which is conjugated subsequently in phase II to a glucopyranoside, a typical plant specific metabolite. After exposure to 10 and 100 μM diclofenac a concentration dependent formation of the hydroxylated metabolite was observed, while the formation of the phase II metabolite OH-diclofenac glucopyranoside was not positively affected by the higher concentration. To our knowledge this is the first time these two human painkiller metabolites are shown to occur in plant tissues. Copyright © 2012 Elsevier B.V. All rights reserved.

Concentration-dependent photodegradation kinetics and hydroxyl-radical oxidation of phenicol antibiotics.

Science.gov (United States)

Li, Kai; Zhang, Peng; Ge, Linke; Ren, Honglei; Yu, Chunyan; Chen, Xiaoyang; Zhao, Yuanfeng

2014-09-01

Thiamphenicol and florfenicol are two phenicol antibiotics widely used in aquaculture and are ubiquitous as micropollutants in surface waters. The present study investigated their photodegradation kinetics, hydroxyl-radical (OH) oxidation reactivities and products. Firstly, the photolytic kinetics of the phenicols in pure water was studied as a function of initial concentrations (C0) under UV-vis irradiation (λ>200nm). It was found that the kinetics was influenced by C0. A linear plot of the pseudo-first-order rate constant vs C0 was observed with a negative slope. Secondly, the reaction between the phenicol antibiotics and OH was examined with a competition kinetic method under simulated solar irradiation (λ>290nm), which quantified their bimolecular reaction rate constants of (2.13±0.02)×10(9)M(-1)s(-1) and (1.82±0.10)×10(9)M(-1)s(-1) for thiamphenicol and florfenicol, respectively. Then the corresponding OH oxidated half-lives in sunlit surface waters were calculated to be 90.5-106.1h. Some main intermediates were formed from the reaction, which suggested that the two phenicols underwent hydroxylation, oxygenation and dehydrogenation when OH existed. These results are of importance to assess the phenicol persistence in wastewater treatment and sunlit surface waters. Copyright © 2014 Elsevier Ltd. All rights reserved.

Hydroxyl radical induced cross-linking of cytosine and tyrosine in nucleohistone

International Nuclear Information System (INIS)

Gajewski, E.; Dizdaroglu, M.

1990-01-01

Hydroxyl radical induced formation of a DNA-protein cross-link involving cytosine and tyrosine in nucleohistone in buffered aqueous solution is reported. The technique of gas chromatography-mass spectrometry was used for this investigation. A γ-irradiated aqueous mixture of cytosine and tyrosine was first investigated in order to obtain gas chromatographic-mass spectrometric properties of possible cytosine-tyrosine cross-links. One cross-link was observed, and its structure was identified as the product from the formation of a covalent bond between carbon 6 of cytosine and carbon 3 of tyrosine. With the use of gas chromatography-mass spectrometry with selected-ion monitoring, this cytosine-tyrosine cross-link was identified in acidic hydrolysates of calf thymus nucleohistone γ-irradiated in N 2 O-saturated aqueous solution. The yield of this DNA-protein cross-link in nucleohistone was found to be a linear function of the radiation dose in the range of 100-500 Gy (J·kg -1 ). This yield amounted to 0.05 nmol·J -1 . Mechanisms underlying the formation of the cytosine-tyrosine cross-link in nucleohistone were proposed to involve radical-radical and/or radical addition reactions of hydroxyl adduct radicals of cytosine and tyrosine moieties, forming a covalent bond between carbon 6 of cytosine and carbon 3 of tyrosine. When oxygen was present in irradiated solutions, no cytosine-tyrosine cross-links were observed

Fast MAS ¹H NMR Study of Water Adsorption and Dissociation on the (100) Surface of Ceria Nanocubes: A Fully Hydroxylated, Hydrophobic Ceria Surface

Energy Technology Data Exchange (ETDEWEB)

Gill, Lance [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Beste, Ariana [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Joint Institute for Computational Sciences (JIBS); Univ. of Tennessee, Knoxville, TN (United States); Chen, Banghao [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Li, Meijun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Mann, Amanda K. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Overbury, Steven H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Hagaman, Edward W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division

2017-03-22

¹H nuclear magnetic resonance (NMR) spectroscopy was used to study hydroxylic surface species on ceria nanocubes, a crystalline, high-surface-area CeO₂ that presents mostly (100) facets. Water adsorption and desorption experiments in combination with fast magic angle spinning (MAS, 20–40 kHz) 1H NMR provide high-resolution ¹H spectra that allow the observation of ten resonance bands (water or hydroxyl) on or under the (100) surface. Assignments were made using a combination of adsorption and temperature-programmed desorption, quantitative spin counting, deuterium exchange, spin–lattice (T₁) and spin–spin (T₂) relaxation, and DFT calculations. In air, the (100) surface exists as a fully hydroxylated surface. Water adsorption and dissociation on dry ceria surfaces occur first at oxygen vacancies, but Ce³⁺ centers are not required since water dissociation is barrier-less on the fully oxidized surface. Surface $-$OH functionality occurs in two resolved bands representing isolated $-$OH (1 ppm) and hydrogen-bonded $-$OH (9 ppm), the latter being dominant. Deuterium exchange of surface hydroxyls with D₂O does not occur under mild or forcing conditions. Despite large differences in the T₁ of surface hydroxyls and physisorbed water, surface hydroxyl T₁ values are independent of the presence or absence of physisorbed water, demonstrating that the protons within these two functional group pools are not in intimate contact. These observations show that, once hydroxylated, the surface $-$OH functionality preferentially forms hydrogen bonds with surface lattice oxygen, i.e., the hydroxylated (100) surface of ceria is hydrophobic. Near this surface it is energetically more favorable for physisorbed water to hydrogen bond to itself rather than to the surface. DFT calculations support this notion. Impurity Na⁺ remaining in incompletely washed ceria nanocubes

Peripheral ameloblastic fibro-odontoma or peripheral developing complex odontoma: report of a case

DEFF Research Database (Denmark)

Reibel, Jesper; Grønbæk, Anni Birgitte; Poulsen, Sven

2011-01-01

BACKGROUND. Peripheral (extraosseous) odontogenic tumors are rare. CASE REPORT. This report describes a case which illustrates the clinical and histopathological features of a lesion in an 8-year-old, healthy Caucasian girl that on purely morphological grounds would seem to be an ameloblastic fibro-odontoma......, but may represent a case of a peripheral developing complex odontoma. CONCLUSION. Conservative surgical enucleation of the lesion was followed by unbcomplicated healing and no recurrence was seen....

Measurement of lower limb alignment: there are within-person differences between weight-bearing and non-weight-bearing measurement modalities.

Science.gov (United States)

Schoenmakers, Daphne A L; Feczko, Peter Z; Boonen, Bert; Schotanus, Martijn G M; Kort, Nanne P; Emans, Pieter J

2017-11-01

Previous studies have compared weight-bearing mechanical leg axis (MLA) measurements to non-weight-bearing measurement modalities. Most of these studies compared mean or median values and did not analyse within-person differences between measurements. This study evaluates the within-person agreement of MLA measurements between weight-bearing full-length radiographs (FLR) and non-weight-bearing measurement modalities (computer-assisted surgery (CAS) navigation or MRI). Two independent observers measured the MLA on pre- and postoperative weight-bearing FLR in 168 patients. These measurements were compared to non-weight-bearing measurements obtained by CAS navigation or MRI. Absolute differences in individual subjects were calculated to determine the agreement between measurement modalities. Linear regression was used to evaluate the possibility that other independent variables impact the differences in measurements. A difference was found in preoperative measurements between FLR and CAS navigation (mean of 2.5° with limit of agreement (1.96 SD) of 6.4°), as well as between FLR and MRI measurements (mean of 2.4° with limit of agreement (1.96 SD) of 6.9°). Postoperatively, the mean difference between MLA measured on FLR compared to CAS navigation was 1.5° (limit of agreement (1.96 SD) of 4.6°). Linear regression analysis showed that weight-bearing MLA measurements vary significantly from non-weight-bearing MLA measurements. Differences were more severe in patients with mediolateral instability (p = 0.010), age (p = 0.049) and ≥3° varus or valgus alignment (p = 0.008). The clinical importance of this study lies in the finding that there are within-person differences between weight-bearing and non-weight-bearing measurement modalities. This has implications for preoperative planning, performing total knee arthroplasty (TKA), and clinical follow-up after TKA surgery using CAS navigation or patient-specific instrumentation. III.

Cool Polar Bears: Dabbing on the Texture

Science.gov (United States)

O'Connell, Jean

2011-01-01

In this article, the author describes how her second-graders created their cool polar bears. The students used the elements of shape and texture to create the bears. They used Monet's technique of dabbing paint so as to give the bear some texture on his fur.

Promoting peripheral myelin repair

OpenAIRE

Zhou, Ye; Notterpek, Lucia

2016-01-01

Compared to the central nervous system (CNS), peripheral nerves have a remarkable ability to regenerate and remyelinate. This regenerative capacity to a large extent is dependent on and supported by Schwann cells, the myelin-forming glial cells of the peripheral nervous system (PNS). In a variety of paradigms, Schwann cells are critical in the removal of the degenerated tissue, which is followed by remyelination of newly-regenerated axons. This unique plasticity of Schwann cells has been the ...

Superior long-term survival for fixed bearing compared with mobile bearing in ligament-balanced total knee arthroplasty.

Science.gov (United States)

Heesterbeek, P J C; van Houten, A H; Klenk, J S; Eijer, H; Christen, B; Wymenga, A B; Schuster, A J

2018-05-01

Only few long-term data on ligament-balanced cruciate-retaining total knee arthroplasty (CR TKA) are currently available. Either a mobile- or fixed-bearing insert can be chosen, which showed good mid-term outcome and few complications and revisions. This multi-centre retrospective cross-sectional cohort study investigated the 12-year results of primary TKA using a balancing gap technique and compared survival and clinical outcome between fixed and mobile inserts. In this retrospective cross-sectional cohort study, 557 cases of three clinics (2 Swiss, 1 Dutch) operated between 1998 and 2003 with the first series of a TKA implanted with a balanced gap technique (433 (77.7%) fixed, 124 (22.3%) mobile (anterior-posterior gliding (7-9 mm) and rotational (15°) degrees of freedom) inserts) were included for survival analysis (Kaplan-Meier, by insert type). At the 12-year follow-up (FU) examination of 189 cases, range of motion, knee society score (KSS), numeric rating scale (NRS) for pain and satisfaction were determined and radiographs were evaluated by median tests, by insert type. Of 521 cases available for analysis, 28 (5.4%; 11 fixed, 17 mobile bearing) were revised. Mean cumulative survival after 12.4 years was 97.0% (95% CI 94.7-98.4) for fixed bearings and 85.4% (95% CI 77.5-90.7) after 12.2 years for mobile bearings, p bearings. This study showed a superior survival for fixed bearing compared with mobile bearing in a CR TKA using a ligament-balanced technique after more than 12 years. Clinical outcomes are excellent to good after long-term follow-up, and similar for fixed and mobile bearing. Therapeutic studies-retrospective cohort study, Level III.

On the Design of Tilting-Pad Thrust Bearings

DEFF Research Database (Denmark)

Heinrichson, Niels

2007-01-01

Pockets are often machined in the surfaces of tilting-pad thrust bearings to allow for hydrostatic jacking in the start-up phase. Pockets and other recesses in the surfaces of bearing pads influence the pressure distribution and thereby the position of the pivot resulting in the most advantageous...... based on the Reynolds equation are used. They include the effects of variations of viscosity with temperature and the deformation of the bearing pads due to pressure and thermal gradients. The models are validated using measurements. Tilting-pad bearings of standard design are studied and the influences...... of the friction loss. Both this bearing and the bearing design with enclosed recesses in the high-pressure regions of the pads suffer from a higher sensitivity to the position of the pivot. The design of such bearing is therefore no trivial task....

Bearing Health Assessment Based on Chaotic Characteristics

Directory of Open Access Journals (Sweden)

Chen Lu

2013-01-01

Full Text Available Vibration signals extracted from rotating parts of machinery carry a lot of useful information about the condition of operating machine. Due to the strong non-linear, complex and non-stationary characteristics of vibration signals from working bearings, an accurate and reliable health assessment method for bearing is necessary. This paper proposes to utilize the selected chaotic characteristics of vibration signal for health assessment of a bearing by using self-organizing map (SOM. Both Grassberger-Procaccia algorithm and Takens' theory are employed to calculate the characteristic vector which includes three chaotic characteristics, such as correlation dimension, largest Lyapunov exponent and Kolmogorov entropy. After that, SOM is used to map the three corresponding characteristics into a confidence value (CV which represents the health state of the bearing. Finally, a case study based on vibration datasets of a group of testing bearings was conducted to demonstrate that the proposed method can reliably assess the health state of bearing.

Mechanical design problems associated with turbopump fluid film bearings

Science.gov (United States)

Evces, Charles R.

1990-01-01

Most high speed cryogenic turbopumps for liquid propulsion rocket engines currently use ball or roller contact bearings for rotor support. The operating speeds, loads, clearances, and environments of these pumps combine to make bearing wear a limiting factor on turbopump life. An example is the high pressure oxygen turbopump (HPOTP) used in the Space Shuttle Main Engine (SSME). Although the HPOTP design life is 27,000 seconds at 30,000 rpms, or approximately 50 missions, bearings must currently be replaced after 2 missions. One solution to the bearing wear problem in the HPOTP, as well as in future turbopump designs, is the utilization of fluid film bearings in lieu of continuous contact bearings. Hydrostatic, hydrodynamic, and damping seal bearings are all replacement candidates for contact bearings in rocket engine high speed turbomachinery. These three types of fluid film bearings have different operating characteristics, but they share a common set of mechanical design opportunities and difficulties. Results of research to define some of the mechanical design issues are given. Problems considered include transient strat/stop rub, non-operational rotor support, bearing wear inspection and measurement, and bearing fluid supply route. Emphasis is given to the HPOTP preburner pump (PBP) bearing, but the results are pertinent to high-speed cryogenic turbomachinery in general.

Partial tooth gear bearings

Science.gov (United States)

Vranish, John M. (Inventor)

2010-01-01

A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

Peripheral cemento-ossifying fibroma of maxilla.

Science.gov (United States)

Chatterjee, Anirban; Ajmera, Neha; Singh, Amit

2010-07-01

Peripheral cemento-ossifying fibroma is a reactive gingival overgrowth occurring frequently in anterior maxilla. It is a slow-growing benign tumor which may lead to pathologic migration and other periodontal problems, so it should be excised as soon as possible. The recurrence rate of peripheral cemento-ossifying fibroma is reported to be 8% to 20%, so a close postoperative follow-up is required. Herein, we are reporting a similar case of peripheral cemento-ossifying fibroma in the maxillary anterior region.

A Brief Review on Electro-generated Hydroxyl Radical for Organic Wastewater Mineralization

Directory of Open Access Journals (Sweden)

Ervin Nurhayati

2016-05-01

Full Text Available Hydroxyl radical is a highly reactive oxidizing agent that can be electrochemically generated on the surface of Boron doped diamond (BDD anode. Once generated, this radical will non-selectively mineralize organic pollutants to carbon dioxide, water and organic anions as the oxidation products. Its application in Advanced Oxidation Process (AOP to degrade nonbiodegradable even the recalcitrant pollutants in wastewater has been increasingly studied and even applied.

What Can We Learn?--The Algonquin Bear Attack.

Science.gov (United States)

Strickland, Dan

1992-01-01

Describes a bear attack in Algonquin Park in Lake Opeongo (Canada) in which a man and woman were killed. Hypothesizes that the bear deliberately preyed on its victims and concludes that the bear was physically normal. Despite this isolated attack, the chance of being attacked by a black bear when camping is virtually nonexistent. (KS)

7 CFR 761.53 - Interest bearing accounts.

Science.gov (United States)

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Interest bearing accounts. 761.53 Section 761.53... AGRICULTURE SPECIAL PROGRAMS GENERAL PROGRAM ADMINISTRATION Supervised Bank Accounts § 761.53 Interest bearing accounts. (a) A supervised bank account, if possible, will be established as an interest bearing deposit...

Active magnetic bearings: As applied to centrifugal pumps

Science.gov (United States)

Nelik, Lev; Cooper, Paul; Jones, Graham; Galecki, Dennis; Pinckney, Frank; Kirk, Gordon

1992-05-01

Application of magnetic bearings to boiler feed pumps presents various attractive features, such as longer bearing life, lower maintenance costs, and improved operability through control of the rotordynamics. Magnetic bearings were fitted to an eight-stage, 600 hp boiler feed pump, which generates 2600 ft of heat at 680 gpm and 3560 rpm. In addition to the varied and severe operating environment in steady state operation of this pump in a power plant, it is also subjected to transient loads during frequent starts and stops. These loads can now be measured by the in-built instrumentation of the magnetic bearings. Following site installation, a follow-up bearing tune-up was performed, and pump transient response testing was conducted. The bearing response was completely satisfactory, ensuring trouble-free pump operation even in the range of reduced load. The experience gained so far through design and testing proves feasibility of magnetic bearings for boiler feed pumps, which sets the stage for application of even higher energy centrifugal pumps equipped with magnetic bearings.

Coaching Peripheral Vision Training for Soccer Athletes

Science.gov (United States)

Marques, Nelson Kautzner, Jr.

2010-01-01

Brazilian Soccer began developing its current emphasis on peripheral vision in the late 1950s, by initiative of coach of the Canto do Rio Football Club, in Niteroi, Rio de Janeiro, a pioneer in the development of peripheral vision training in soccer players. Peripheral vision training gained world relevance when a young talent from Canto do Rio,…

49 CFR 230.102 - Tender plain bearing journal boxes.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and bearing...

[Ultrasound-guided peripheral catheterization].

Science.gov (United States)

Salleras-Duran, Laia; Fuentes-Pumarola, Concepció

2016-01-01

Peripheral catheterization is a technique that can be difficult in some patients. Some studies have recently described the use of ultrasound to guide the venous catheterization. To describe the success rate, time required, complications of ultrasound-guided peripheral venous catheterization. and patients and professionals satisfaction The search was performed in databases (Medline-PubMed, Cochrane Library, CINAHL and Cuiden Plus) for studies published about ultrasound-guided peripheral venous catheterization performed on patients that provided results on the success of the technique, complications, time used, patient satisfaction and the type of professional who performed the technique. A total of 21 studies were included. Most of them get a higher success rate 80% in the catheterization ecoguide and time it is not higher than the traditional technique. The Technical complications analyzed were arterial puncture rates and lower nerve 10%. In all studies measuring and comparing patient satisfaction in the art ecoguide is greater. Various professional groups perform the technique. The use of ultrasound for peripheral pipes has a high success rate, complications are rare and the time used is similar to that of the traditional technique. The technique of inserting catheters through ultrasound may be learned by any professional group performing venipuncture. Finally, it gets underscores the high patient satisfaction with the use of this technique. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

Trichinella and polar bears: a limited risk for humans.

Science.gov (United States)

Dupouy-Camet, J; Bourée, P; Yera, H

2017-07-01

In this review, we identified 63 cases reported since World War II of human trichinellosis linked to the consumption of parasitized polar bear (Ursus maritimus) meat. This low number contrasts to the numerous cases of human trichinellosis related to consumption of the meat of black (U. americanus) or brown bears (U. arctos). The prevalence of Trichinella infection is high in bears, but larval muscular burden is usually lower in polar bears compared to other bear species. Polar bears, therefore, seem to play a limited role in the transmission of trichinellosis to humans, as native residents living in the Arctic traditionally consume well-cooked bear meat, and travellers and foreign hunters have only limited access to this protected species due to the declining polar bear population.

Synthesis of hydroxylated and methoxylated polybrominated diphenyl ethers

Institute of Scientific and Technical Information of China (English)

ZHENG Ke-wen; GAO Li-ping; CAO Jie; YU Hai-wen; ZHANG Zhang

2009-01-01

Hydroxylated/methoxylated polybrominated diphenyl ethers (OH/MeO-PBDEs) are not only detected as natural products, but also regarded as metabolites formed from polybrominated diphenyl ethers (PBDEs), which are widely used as flame-retardants in various materials. The aim of the present study was to synthesize authentic OH-PBDEs and MeO-PBDEs, as reference standards for environmental exploration. Twenty OH-PBDEs and their corresponding MeO-PBDEs containing three to six bromine atoms were synthesized via a trial of reactions including coupling, oxidation, bromination, methylation, etc. The products were characterized by GC-MS and 1H-NMR spectroscopy in the work. As results show, all compounds synthesized were up to 99% on purity and be reqarded as authentic standards for detecting the chemical pollutants in the emvironment.