Refinement of the experimental dynamic structure factor for liquid para-hydrogen and ortho-deuterium using semi-classical quantum simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Kyle K. G., E-mail: kylesmith@utexas.edu; Rossky, Peter J., E-mail: peter.rossky@austin.utexas.edu; Poulsen, Jens Aage, E-mail: jens72@chem.gu.se

The dynamic structure factor of liquid para-hydrogen and ortho-deuterium in corresponding thermodynamic states (T = 20.0 K, n = 21.24 nm{sup −3}) and (T = 23.0 K, n = 24.61 nm{sup −3}), respectively, has been computed by both the Feynman-Kleinert linearized path-integral (FK-LPI) and Ring-Polymer Molecular Dynamics (RPMD) methods and compared with Inelastic X Ray Scattering spectra. The combined use of computational and experimental methods enabled us to reduce experimental uncertainties in the determination of the true sample spectrum. Furthermore, the refined experimental spectrum of para-hydrogen and ortho-deuterium is consistently reproduced by both FK-LPI and RPMD results at momentum transfers lower than 12.8 nm{sup −1}.more » At larger momentum transfers the FK-LPI results agree with experiment much better for ortho-deuterium than for para-hydrogen. More specifically we found that for k ∼ 20.0 nm{sup −1} para-hydrogen provides a test case for improved approximations to quantum dynamics.« less

CLSI-based transference and verification of CALIPER pediatric reference intervals for 29 Ortho VITROS 5600 chemistry assays.

PubMed

Higgins, Victoria; Truong, Dorothy; Woroch, Amy; Chan, Man Khun; Tahmasebi, Houman; Adeli, Khosrow

2018-03-01

Evidence-based reference intervals (RIs) are essential to accurately interpret pediatric laboratory test results. To fill gaps in pediatric RIs, the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) project developed an age- and sex-specific pediatric RI database based on healthy pediatric subjects. Originally established for Abbott ARCHITECT assays, CALIPER RIs were transferred to assays on Beckman, Roche, Siemens, and Ortho analytical platforms. This study provides transferred reference intervals for 29 biochemical assays for the Ortho VITROS 5600 Chemistry System (Ortho). Based on Clinical Laboratory Standards Institute (CLSI) guidelines, a method comparison analysis was performed by measuring approximately 200 patient serum samples using Abbott and Ortho assays. The equation of the line of best fit was calculated and the appropriateness of the linear model was assessed. This equation was used to transfer RIs from Abbott to Ortho assays. Transferred RIs were verified using 84 healthy pediatric serum samples from the CALIPER cohort. RIs for most chemistry analytes successfully transferred from Abbott to Ortho assays. Calcium and CO 2 did not meet statistical criteria for transference (r 2 <0.70). Of the 32 transferred reference intervals, 29 successfully verified with approximately 90% of results from reference samples falling within transferred confidence limits. Transferred RIs for total bilirubin, magnesium, and LDH did not meet verification criteria and are not reported. This study broadens the utility of the CALIPER pediatric RI database to laboratories using Ortho VITROS 5600 biochemical assays. Clinical laboratories should verify CALIPER reference intervals for their specific analytical platform and local population as recommended by CLSI. Copyright © 2018 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

COBALT-60 Gamma Irradiation of Shrimp.

NASA Astrophysics Data System (ADS)

Sullivan, Nancy L. B.

Meta- and ortho-tyrosine were measured using high performance liquid chromatography (HPLC) in conjunction with electrochemical detection in shrimp irradiated using cobalt-60 gamma radiation in the absorbed dose range 0.8 to 6.0 kGy, in nonirradiated shrimp, and in bovine serum albumin (BSA) irradiated in dilute aqueous solution at 25.0 kGy. Ortho-tyrosine was measured in nonirradiated BSA. Para-, meta-, and ortho-tyrosine were measured using HPLC in conjunction with uv-absorption detection in dilute aqueous solutions of phenylalanine irradiated in the absorbed dose range 16.0 to 195.0 kGy. The measured yields of tyrosine isomers were approximately linear as a function of absorbed dose in shrimp, and in irradiated solutions of phenylalanine up to 37.0 kGy. The occurrence of meta- and ortho-tyrosine, which had formerly been considered unique radiolytic products, has not previously been reported in nonirradiated shrimp or BSA. The conventional hydrolyzation and analytical techniques used in the present study to measure meta- and ortho-tyrosine may provide the basis for a method to detect and determine the dose used in food irradiation.

OrthoMCL: Identification of Ortholog Groups for Eukaryotic Genomes

PubMed Central

Li, Li; Stoeckert, Christian J.; Roos, David S.

2003-01-01

The identification of orthologous groups is useful for genome annotation, studies on gene/protein evolution, comparative genomics, and the identification of taxonomically restricted sequences. Methods successfully exploited for prokaryotic genome analysis have proved difficult to apply to eukaryotes, however, as larger genomes may contain multiple paralogous genes, and sequence information is often incomplete. OrthoMCL provides a scalable method for constructing orthologous groups across multiple eukaryotic taxa, using a Markov Cluster algorithm to group (putative) orthologs and paralogs. This method performs similarly to the INPARANOID algorithm when applied to two genomes, but can be extended to cluster orthologs from multiple species. OrthoMCL clusters are coherent with groups identified by EGO, but improved recognition of “recent” paralogs permits overlapping EGO groups representing the same gene to be merged. Comparison with previously assigned EC annotations suggests a high degree of reliability, implying utility for automated eukaryotic genome annotation. OrthoMCL has been applied to the proteome data set from seven publicly available genomes (human, fly, worm, yeast, Arabidopsis, the malaria parasite Plasmodium falciparum, and Escherichia coli). A Web interface allows queries based on individual genes or user-defined phylogenetic patterns (http://www.cbil.upenn.edu/gene-family). Analysis of clusters incorporating P. falciparum genes identifies numerous enzymes that were incompletely annotated in first-pass annotation of the parasite genome. PMID:12952885

Phase transition and intramolecular hydrogen bonding in nitro derivatives of ortho-hydroxy acetophenones

NASA Astrophysics Data System (ADS)

Filarowski, A.; Kochel, A.; Koll, A.; Bator, G.; Mukherjee, S.

2006-03-01

The crystal structures of two ortho-hydroxy aryl ketones (5-chloro-3-nitro-2-hydroxyacetophenone, 5-methyl-3-nitro-2-hydroxyacetophenone and the complex 5-chloro-3-nitro-2-hydroxyacetophenone with 2-aminobenzoic acid (anthranilic acid)) were determined by X-ray diffraction. The existence of an intramolecular hydrogen bond of enol character between the hydroxyl and acetyl groups was found by the X-ray method. The enol character was also confirmed by DFT (B3LYP/6-31+G(d,p)) calculations. A phase transition was found at 138 K in 5-chloro-3-nitro-2-hydroxyacetophenone. This phase transition was investigated by differential scanning calorimetry (DSC), dilatometry, and the dielectric method. A study of the nitro-group dynamics in the ortho-hydroxy acetophenones was carried out with DFT (B3LYP/6-31+G(d,p)) calculations.

Practical in-situ determination of ortho-para hydrogen ratios via fiber-optic based Raman spectroscopy

DOE PAGES

Sutherland, Liese -Marie; Knudson, James N.; Mocko, Michal; ...

2015-12-17

An experiment was designed and developed to prototype a fiber-optic-based laser system, which measures the ratio of ortho-hydrogen to para-hydrogen in an operating neutron moderator system at the Los Alamos Neutron Science Center (LANSCE) spallation neutron source. Preliminary measurements resulted in an ortho to para ratio of 3.06:1, which is within acceptable agreement with the previously published ratio. As a result, the successful demonstration of Raman Spectroscopy for this measurement is expected to lead to a practical method that can be applied for similar in-situ measurements at operating neutron spallation sources.

Practical in-situ determination of ortho-para hydrogen ratios via fiber-optic based Raman spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutherland, Liese -Marie; Knudson, James N.; Mocko, Michal

An experiment was designed and developed to prototype a fiber-optic-based laser system, which measures the ratio of ortho-hydrogen to para-hydrogen in an operating neutron moderator system at the Los Alamos Neutron Science Center (LANSCE) spallation neutron source. Preliminary measurements resulted in an ortho to para ratio of 3.06:1, which is within acceptable agreement with the previously published ratio. As a result, the successful demonstration of Raman Spectroscopy for this measurement is expected to lead to a practical method that can be applied for similar in-situ measurements at operating neutron spallation sources.

Characterization of Slosh Damping for Ortho-Grid and Iso-Grid Internal Tank Structures

NASA Technical Reports Server (NTRS)

Westra, Douglas G.; Sansone, Marco D.; Eberhart, Chad J.; West, Jeffrey S.

2016-01-01

Grid stiffened tank structures such as Ortho-Grid and Iso-Grid are widely used in cryogenic tanks for providing stiffening to the tank while reducing mass, compared to tank walls of constant cross-section. If the structure is internal to the tank, it will positively affect the fluid dynamic behavior of the liquid propellant, in regard to fluid slosh damping. As NASA and commercial companies endeavor to explore the solar system, vehicles will by necessity become more mass efficient, and design margin will be reduced where possible. Therefore, if the damping characteristics of the Ortho-Grid and Iso-Grid structure is understood, their positive damping effect can be taken into account in the systems design process. Historically, damping by internal structures has been characterized by rules of thumb and for Ortho-Grid, empirical design tools intended for slosh baffles of much larger cross-section have been used. There is little or no information available to characterize the slosh behavior of Iso-Grid internal structure. Therefore, to take advantage of these structures for their positive damping effects, there is much need for obtaining additional data and tools to characterize them. Recently, the NASA Marshall Space Flight Center conducted both sub-scale testing and computational fluid dynamics (CFD) simulations of slosh damping for Ortho-Grid and Iso-Grid tanks for cylindrical tanks containing water. Enhanced grid meshing techniques were applied to the geometrically detailed and complex Ortho-Grid and Iso-Grid structures. The Loci-STREAM CFD program with the Volume of Fluid Method module for tracking and locating the water-air fluid interface was used to conduct the simulations. The CFD simulations were validated with the test data and new empirical models for predicting damping and frequency of Ortho-Grid and Iso-Grid structures were generated.

Theoretical study of the design of a catalyst for para to ortho hydrogen conversion

NASA Technical Reports Server (NTRS)

Coffman, Robert E.

1992-01-01

The theory of Petzinger and Scalapino (1973) was thoroughly reviewed, and all of the basic equations for paramagnetic para to ortho hydrogen catalysis re-derived. There are only a few minor phase errors and errors of omission in the description of the theory. Three models (described by Petzinger and Scalapino) for the rate of para to ortho H2 catalysis were worked out, and uniform agreement obtained to within a constant factor of 2 pi. The analytical methods developed in the course of this study were then extended to two new models, which more adequately describe the process of surface catalysis including transfer of hydrogen molecules onto and off of the surface. All five equations for the para to ortho catalytic rate of conversion are described. The two new equations describe the catalytic rate for these models: H2 on the surface is a 2-D gas with lifetime tau; and H2 on the surface is a 2-D liquid undergoing Brownian motion (diffusion) with surface lifetime tau.

Efficient synthesis of anacardic acid analogues and their antibacterial activities.

PubMed

Mamidyala, Sreeman K; Ramu, Soumya; Huang, Johnny X; Robertson, Avril A B; Cooper, Matthew A

2013-03-15

Anacardic acid derivatives exhibit a broad range of biological activities. In this report, an efficient method for the synthesis of anacardic acid derivatives was explored, and a small set of salicylic acid variants synthesised retaining a constant hydrophobic element (a naphthyl tail). The naphthyl side chain was introduced via Wittig reaction and the aldehyde installed using directed ortho-metalation reaction of the substituted o-anisic acids. The failure of ortho-metalation using unprotected carboxylic acid group compelled us to use directed ortho-metalation in which a tertiary amide was used as a strong ortho-directing group. In the initial route, tertiary amide cleavage during final step was challenging, but cleaving the tertiary amide before Wittig reaction was beneficial. The Wittig reaction with protected carboxylic group (methyl ester) resulted in side-products whereas using sodium salt resulted in higher yields. The novel compounds were screened for antibacterial activity and cytotoxicity. Although substitution on the salicylic head group enhanced antibacterial activities they also enhanced cytotoxicity. Copyright © 2013 Elsevier Ltd. All rights reserved.

Introduction and Testing of a Monitoring and Colony-Mapping Method for Waterbird Populations That Uses High-Speed and Ultra-Detailed Aerial Remote Sensing

PubMed Central

Bakó, Gábor; Tolnai, Márton; Takács, Ádám

2014-01-01

Remote sensing is a method that collects data of the Earth's surface without causing disturbances. Thus, it is worthwhile to use remote sensing methods to survey endangered ecosystems, as the studied species will behave naturally while undisturbed. The latest passive optical remote sensing solutions permit surveys from long distances. State-of-the-art highly sensitive sensor systems allow high spatial resolution image acquisition at high altitudes and at high flying speeds, even in low-visibility conditions. As the aerial imagery captured by an airplane covers the entire study area, all the animals present in that area can be recorded. A population assessment is conducted by visual interpretations of an ortho image map. The basic objective of this study is to determine whether small- and medium-sized bird species are recognizable in the ortho images by using high spatial resolution aerial cameras. The spatial resolution needed for identifying the bird species in the ortho image map was studied. The survey was adjusted to determine the number of birds in a colony at a given time. PMID:25046012

The Ratio of Ortho- to Para-H2 in Photodissociation Regions

NASA Technical Reports Server (NTRS)

Sternberg, Amiel; Neufeld, David A.

1999-01-01

We discuss the ratio of ortho- to para-H2 in photodissociation regions (PDRs). We draw attention to an apparent confusion in the literature between the ortho-to-para ratio of molecules in FUV-pumped vibrationally excited states and the total H2 ortho-to-para abundance ratio. These ratios are not the same because the process of FUV pumping of fluorescent H2 emission in PDRs occurs via optically thick absorption lines. Thus gas with an equilibrium ratio of ortho- to para-H2 equal to 3 will yield FUV-pumped vibrationally excited ortho-to-para ratios smaller than 3, because the ortho-H2 pumping rates are preferentially reduced by optical depth effects. Indeed, if the ortho and para pumping lines are on the "square root" part of the curve of growth, then the expected ratio of ortho and para vibrational line strengths is 3(sup 1/2) approximately 1.7, close to the typically observed value. Thus, contrary to what has sometimes been stated in the literature, most previous measurements of the ratio of ortho- to para-H2 in vibrationally excited states are entirely consistent with a total ortho-to-para ratio of 3, the equilibrium value for temperatures greater than 200 K. We present an analysis and several detailed models that illustrate the relationship between the total ratios of ortho- to para-H2 and the vibrationally excited ortho-to-para ratios in PDRs. Recent Infrared Space Observatory measurements of pure rotational and vibrational H2 emissions from the PDR in the star-forming region S140 provide strong observational support for our conclusions.

Electrical transport properties of spray deposited transparent conducting ortho-Zn2SnO4 thin films

NASA Astrophysics Data System (ADS)

Ramarajan, R.; Thangaraju, K.; Babu, R. Ramesh; Joseph, D. Paul

2018-04-01

Ortho Zinc Stannate (Zn2SnO4) exhibits excellent electrical and optical properties to serve as alternate transparent electrode in optoelectronic devices. Here we have optimized ortho-Zn2SnO4 thin film by spray pyrolysis method. Deposition was done onto a pre-heated glass substrate at a temperature of 400 °C. The XRD pattern indicated films to be polycrystalline with cubic structure. The surface of films had globular and twisted metal sheet like morphologies. Films were transparent in the visible region with band gap around 3.6 eV. Transport properties were studied by Hall measurements at 300 K. Activation energies were calculated from Arrhenius's plot from temperature dependent electrical measurements and the conduction mechanism is discussed.

Binding of polychlorinated biphenyls to aquatic humic substances: The role of substrate and sorbate properties on partitioning

USGS Publications Warehouse

Uhle, M.E.; Chin, Y.-P.; Aiken, G.R.; McKnight, Diane M.

1999-01-01

Two ortho- (2,2',5 and 2,2',5,6') and a non-ortho- (3,3',4,4') substituted polychlorinated biphenyl (PCB) congeners were used to study the effects of sorbate structure in binding processes to two lacustrine fulvic acids. Binding constants were determined by solubility enhancement of the solutes by the fulvic acids. The binding of the ortho-trichlorobiphenyl was significantly less than the non-ortho-substituted tetrachlorobiphenyl to both fulvic acids. Surprisingly, the measured ortho-trichlorobiphenyl binding constant to both fulvic acids was approximately the same as the ortho- substituted tetrachlorobiphenyl. The effect of the chlorines in the ortho position inhibits free rotation around the 1,1' carbon bond, thereby making the molecule less able to interact effectively with the fulvic acid substrate relative to its non-ortho-substituted congeners. Finally, binding of all three PCBs to the Great Dismal Swamp fulvic acid was significantly higher than for the Pony Lake sample. This observation is attributable to the former substrate's higher degree of aromaticity and polarizability, which can potentially interact more favorably with the PCBs through an increase in van der Waals type interactions.Two ortho- (2,2???,5 and 2,2???,5,6???) and a non-ortho- (3,3???,4,4???) substituted polychlorinated biphenyl (PCB) congeners were used to study the effects of sorbate structure in binding processes to two lacustrine fulvic acids. Binding constants were determined by solubility enhancement of the solutes by the fulvic acids. The binding of the ortho-trichlorobiphenyl was significantly less than the non-ortho-substituted tetrachlorobiphenyl to both fulvic acids. Surprisingly, the measured ortho-trichlorobiphenyl binding constant to both fulvic acids was approximately the same as the ortho-substituted tetrachlorobiphenyl. The effect of the chlorines in the ortho position inhibits free rotation around the 1,1??? carbon bond, thereby making the molecule less able to interact effectively with the fulvic acid substrate relative to its non-ortho-substituted congeners. Finally, binding of all three PCBs to the Great Dismal Swamp fulvic acid was significantly higher than for the Pony Lake sample. This observation is attributable to the former substrate's higher degree of aromaticity and polarizability, which can potentially interact more favorably with the PCBs through an increase in van der Waals type interactions.

Biological and therapeutic effects of ortho-silicic acid and some ortho-silicic acid-releasing compounds: New perspectives for therapy.

PubMed

Jurkić, Lela Munjas; Cepanec, Ivica; Pavelić, Sandra Kraljević; Pavelić, Krešimir

2013-01-08

Silicon (Si) is the most abundant element present in the Earth's crust besides oxygen. However, the exact biological roles of silicon remain unknown. Moreover, the ortho-silicic acid (H4SiO4), as a major form of bioavailable silicon for both humans and animals, has not been given adequate attention so far. Silicon has already been associated with bone mineralization, collagen synthesis, skin, hair and nails health atherosclerosis, Alzheimer disease, immune system enhancement, and with some other disorders or pharmacological effects. Beside the ortho-silicic acid and its stabilized formulations such as choline chloride-stabilized ortho-silicic acid and sodium or potassium silicates (e.g. M2SiO3; M= Na,K), the most important sources that release ortho-silicic acid as a bioavailable form of silicon are: colloidal silicic acid (hydrated silica gel), silica gel (amorphous silicon dioxide), and zeolites. Although all these compounds are characterized by substantial water insolubility, they release small, but significant, equilibrium concentration of ortho-silicic acid (H4SiO4) in contact with water and physiological fluids. Even though certain pharmacological effects of these compounds might be attributed to specific structural characteristics that result in profound adsorption and absorption properties, they all exhibit similar pharmacological profiles readily comparable to ortho-silicic acid effects. The most unusual ortho-silicic acid-releasing agents are certain types of zeolites, a class of aluminosilicates with well described ion(cation)-exchange properties. Numerous biological activities of some types of zeolites documented so far might probably be attributable to the ortho-silicic acid-releasing property. In this review, we therefore discuss biological and potential therapeutic effects of ortho-silicic acid and ortho-silicic acid -releasing silicon compounds as its major natural sources.

Advanced Hydrogen Liquefaction Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, Joseph; Kromer, Brian; Neu, Ben

2011-09-28

The project identified and quantified ways to reduce the cost of hydrogen liquefaction, and reduce the cost of hydrogen distribution. The goal was to reduce the power consumption by 20% and then to reduce the capital cost. Optimizing the process, improving process equipment, and improving ortho-para conversion significantly reduced the power consumption of liquefaction, but by less than 20%. Because the efficiency improvement was less than the target, the program was stopped before the capital cost was addressed. These efficiency improvements could provide a benefit to the public to improve the design of future hydrogen liquefiers. The project increased themore » understanding of hydrogen liquefaction by modeling different processes and thoroughly examining ortho-para separation and conversion. The process modeling provided a benefit to the public because the project incorporated para hydrogen into the process modeling software, so liquefaction processes can be modeled more accurately than using only normal hydrogen. Adding catalyst to the first heat exchanger, a simple method to reduce liquefaction power, was identified, analyzed, and quantified. The demonstrated performance of ortho-para separation is sufficient for at least one identified process concept to show reduced power cost when compared to hydrogen liquefaction processes using conventional ortho-para conversion. The impact of improved ortho-para conversion can be significant because ortho para conversion uses about 20-25% of the total liquefaction power, but performance improvement is necessary to realize a substantial benefit. Most of the energy used in liquefaction is for gas compression. Improvements in hydrogen compression will have a significant impact on overall liquefier efficiency. Improvements to turbines, heat exchangers, and other process equipment will have less impact.« less

Digital casts in orthodontics: a comparison of 4 software systems.

PubMed

Westerlund, Anna; Tancredi, Weronika; Ransjö, Maria; Bresin, Andrea; Psonis, Spyros; Torgersson, Olof

2015-04-01

The introduction of digital cast models is inevitable in the otherwise digitized everyday life of orthodontics. The introduction of this new technology, however, is not straightforward, and selecting an appropriate system can be difficult. The aim of the study was to compare 4 orthodontic digital software systems regarding service, features, and usability. Information regarding service offered by the companies was obtained from questionnaires and Web sites. The features of each software system were collected by exploring the user manuals and the software programs. Replicas of pretreatment casts were sent to Cadent (OrthoCAD; Cadent, Carlstadt, NJ), OthoLab (O3DM; OrthoLab, Poznan, Poland), OrthoProof (DigiModel; OrthoProof, Nieuwegein, The Netherlands), and 3Shape (OrthoAnalyzer; 3Shape, Copenhagen, Denmark). The usability of the programs was assessed by experts in interaction design and usability using the "enhanced cognitive walkthrough" method: 4 tasks were defined and performed by a group of domain experts while they were observed by usability experts. The services provided by the companies were similar. Regarding the features, all 4 systems were able to perform basic measurements; however, not all provided the peer assessment rating index or the American Board of Orthodontics analysis, simulation of the treatment with braces, or digital articulation of the casts. All systems demonstrated weaknesses in usability. However, OrthoCAD and 03DM were considered to be easier to learn for first-time users. In general, the usability of these programs was poor and needs to be further developed. Hands-on training supervised by the program experts is recommended for beginners. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Applications of ortho-phenylisonitrile and ortho-N-Boc aniline for the two-step preparation of novel bis-heterocyclic chemotypes.

PubMed

Xu, Zhigang; Shaw, Arthur Y; Nichol, Gary S; Cappelli, Alexandra P; Hulme, Christopher

2012-08-01

Concise routes to five pharmacologically relevant bis-heterocyclic scaffolds are described. Significant molecular complexity is generated in a mere two synthetic operations enabling access to each scaffold. Routes are often improved by microwave irradiation and all utilize isocyanide-based multi-component reaction methods to incorporate the required diversity elements. Common reagents in all initial condensation reactions include 2-(N-Boc-amino)-phenyl-isocyanide 1, mono-Boc-phenylenediamine 2 and ethyl glyoxalate 3.

OrthoVenn: a web server for genome wide comparison and annotation of orthologous clusters across multiple species.

PubMed

Wang, Yi; Coleman-Derr, Devin; Chen, Guoping; Gu, Yong Q

2015-07-01

Genome wide analysis of orthologous clusters is an important component of comparative genomics studies. Identifying the overlap among orthologous clusters can enable us to elucidate the function and evolution of proteins across multiple species. Here, we report a web platform named OrthoVenn that is useful for genome wide comparisons and visualization of orthologous clusters. OrthoVenn provides coverage of vertebrates, metazoa, protists, fungi, plants and bacteria for the comparison of orthologous clusters and also supports uploading of customized protein sequences from user-defined species. An interactive Venn diagram, summary counts, and functional summaries of the disjunction and intersection of clusters shared between species are displayed as part of the OrthoVenn result. OrthoVenn also includes in-depth views of the clusters using various sequence analysis tools. Furthermore, OrthoVenn identifies orthologous clusters of single copy genes and allows for a customized search of clusters of specific genes through key words or BLAST. OrthoVenn is an efficient and user-friendly web server freely accessible at http://probes.pw.usda.gov/OrthoVenn or http://aegilops.wheat.ucdavis.edu/OrthoVenn. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

A Study of Polymer Interactions with Moisture in Polyaniline and its Derivatives

NASA Astrophysics Data System (ADS)

Dyakonov, A. J.; McCormick, B. J.; Kahol, P. K.

1997-03-01

Electron Spin Resonance experiments have been performed under different sample treatments on powders of polyaniline, poly(ortho)diaminobenzene, poly(ortho)chloroaniline, poly(ortho)toluidine, poly(ortho)ethylaniline, and poly(ortho)propylaniline, with the objective of finding various adsorption sites for water molecules. It is found that water molecules are adsorbed at two distinct sites in polyaniline. Implications of these results will be presented in relation to dc conductivity results and the inhomogeneously disordered metal description of polyaniline.

Separation of non-ortho polychlorinated biphenyl congeners on pre-packed carbon tubes. Application to analysis in sewage sludge and soil samples.

PubMed

Molina, L; Cabes, M; Díaz-Ferrero, J; Coll, M; Martí, R; Broto-Puig, F; Comellas, L; Rodríguez-Larena, M C

2000-01-01

The analysis of planar (non-ortho) polychlorinated biphenyls (PCB) by HRGC-ECD or HRGC-HRMS requires a fractionation step to avoid the interferences of the bulk of PCB, usually in much higher concentration than the planar ones. In this paper, a new method, based on the fractionation of PCB on SPE commercial tubes pre-packed with Carbopack B, has been developed. After the extract has been applied on the stationary phase, the bulk of PCD are eluted with 15 ml of hexane (fraction I), mono-ortho PCB with 20 ml of hexane/toluene 99:1 (fraction II) and planar PCB with 20 ml of toluene (fraction III) in a station under vacuum. The method has been validated: accuracy (expressed as recovery in %) is >70% and precision (expressed as % RSD) is <20% considering changes of day, analyst and batch of tubes. The method is linear in the range studied. Other advantages are that the method is simple, rapid and it can be easily automated. The application of this separation to the determination of planar PCB in fly-ash extracts from an intercalibration exercise and to sewage sludge, sediment and soil samples has been successful. In addition, this method removes hydrocarbons from the planar PCB fraction and allows its concentration to very small volumes.

ORTHO-PARA SELECTION RULES IN THE GAS-PHASE CHEMISTRY OF INTERSTELLAR AMMONIA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faure, A.; Hily-Blant, P.; Le Gal, R.

The ortho-para chemistry of ammonia in the cold interstellar medium is investigated using a gas-phase chemical network. Branching ratios for the primary reaction chain involved in the formation and destruction of ortho- and para-NH{sub 3} were derived using angular momentum rules based on the conservation of the nuclear spin. We show that the 'anomalous' ortho-to-para ratio of ammonia ({approx}0.7) observed in various interstellar regions is in fact consistent with nuclear spin selection rules in a para-enriched H{sub 2} gas. This ratio is found to be independent of temperature in the range 5-30 K. We also predict an ortho-to-para ratio ofmore » {approx}2.3 for NH{sub 2}. We conclude that a low ortho-to-para ratio of H{sub 2} naturally drives the ortho-to-para ratios of nitrogen hydrides below the statistical values.« less

Evaluation of the Ortho-Clinical Diagnostics Vitros ECi Anti-HCV test: comparison with three other methods.

PubMed

Watterson, Jeannette M; Stallcup, Paulina; Escamilla, David; Chernay, Patrick; Reyes, Alfred; Trevino, Sylvia C

2007-01-01

After observing a high incidence of low positive hepatitis C virus (HCV) antibody screens by the Ortho-Clinical Vitros ECi test (Orthoclinical Diagnostics, Raritan, NJ), we compared results against those obtained using another chemiluminescent analyzer, as well as two U.S. Food and Drug Administration (FDA)-approved confirmatory methodologies. To ascertain the true anti-HCV status of samples deemed low-positive by the Ortho-Clinical Vitros ECi test, we tested samples using the ADVIA Centaur HCV screen test (Siemens Medical Solutions Diagnostics), the Chiron recombinant immunoblot assay (RIBA) test (Chiron Corp., Emeryville, CA), and the Roche COBAS Amplicor HCV qualitative test (Roche Diagnostics, Indianapolis, IN) in a series of studies. Of 94 specimens positive by Vitros ECi, 19% were observed to be negative by Centaur. A separate study of 91 samples with signal-to-cutoff (s/co) values less than 8.0 showed that all but one was negative for HCV ribonucleic acid (RNA). In comparison with RIBA, 100% (77) samples positive by the Vitros ECi test with s/co values less than 12.0 were negative or indeterminate by RIBA. A final study comparing all four methods side-by-side showed 63% disagreement by Centaur for Vitros ECi low-positive samples, 75% disagreement by RIBA, and 97% disagreement by polymerase chain reaction (PCR). In conclusion, the Ortho-Clinical Vitros ECi Anti-HCV test yields a high rate of false-positive results in the low s/co range in our patient population. (c) 2007 Wiley-Liss, Inc.

Shear bond strength of different adhesives tested in accordance with DIN 13990-1/-2 and using various methods of enamel conditioning.

PubMed

Richter, C; Jost-Brinkmann, P-G

2015-03-01

The purpose of this work was to analyze the shear bond strength (SBS) of different adhesives for orthodontic brackets in accordance with DIN 13990-1/-2, also taking into consideration potential effects arising from different scenarios of enamel conditioning and specimen storage. A total of 390 experiments were performed, with groups of 10 specimens subjected to identical treatments. Three adhesives were tested: Transbond™ XT (3M Unitek, Monrovia, USA), Beauty Ortho Bond (Shofu, Kyoto, Japan), and Fuji Ortho LC (GC Europe, Leuven, Belgium). SBS was evaluated separately at the bracket-adhesive and adhesive-enamel interfaces, as well as the total (enamel-adhesive-bracket) interface. The brackets were metal brackets for upper right central incisors (Discovery® from Dentaurum, Ispringen, Germany). A universal testing machine (Zwick Z010, Ulm, Germany) was used for testing the SBS after 15 min, or after storage in distilled water at 37 °C for 24 h, or after 24 h followed by 500 thermocycles alternating between 5 and 55 °C. Transbond™ XT produced the highest levels of SBS. The least favorable performance was observed with Fuji Ortho LC after enamel conditioning with 10 % polyacrylic acid. Thermocycling did not have a significant influence. Transbond™ XT and Beauty Ortho Bond (but not Fuji Ortho LC) yielded levels of SBS adequate for clinical application (≥ 7 MPa).

FEEDING THE MUMMICHOG (FUNDULUS HERTERCLITUS), A DIET SPIKED WITH NON-ORTHO AND MONO-ORTHO SUBSTITUTED POLYCHLORINATED BIPHENYLS:ACCUMULATION AND EFFECTS

EPA Science Inventory

A laboratory model was developed to predict exposure effects in the field. Accumulation of non-ortho- and mono-ortho-substituted PCBs in liver tissue and their effects on mummichogs (Fundulus heteroclitus) were investigated. An artificial diet spiked with a mixture of eight PCB c...

Ortho-Babinet polarization-interrogating filter: an interferometric approach to polarization measurement.

PubMed

Van Delden, Jay S

2003-07-15

A novel, interferometric, polarization-interrogating filter assembly and method for the simultaneous measurement of all four Stokes parameters across a partially polarized irradiance image in a no-moving-parts, instantaneous, highly sensitive manner is described. In the reported embodiment of the filter, two spatially varying linear retarders and a linear polarizer comprise an ortho-Babinet, polarization-interrogating (OBPI) filter. The OBPI filter uniquely encodes the incident ensemble of electromagnetic wave fronts comprising a partially polarized irradiance image in a controlled, deterministic, spatially varying manner to map the complete state of polarization across the image to local variations in a superposed interference pattern. Experimental interferograms are reported along with a numerical simulation of the method.

Ortho effects in quantitative structure-activity relationships for acetylcholinesterase inhibition by aryl carbamates.

PubMed

Lin, Gialih; Liu, Yu-Chen; Lin, Yan-Fu; Wu, Yon-Gi

2004-10-01

Ortho-substituted phenyl-N-butyl carbamates (1-9) are characterized as "pseudo-pseudo-substrate" inhibitors of acetylcholinesterase. Since the inhibitors protonate at pH 7.0 buffer solution, the virtual inhibition constants (K'is) of the protonated inhibitors are calculated from the equation, - logK'i = - logKi - logKb. The logarithms of the inhibition constant (Ki), the carbamylation constant (k(c)), and the bimolecular inhibition constant (k(i)) for the enzyme inhibitions by carbamates 1-9 are multiply linearly correlated with the Hammett para-substituent constant (sigma(p)), the Taft-Kutter-Hansch ortho steric constant (E(S)), and the Swan-Lupton ortho polar constant (F). Values of rho, delta, and f for the - logKi-, logk(c)-, and logk(i)-correlations are -0.6, -0.16, 0.7; 0.11, 0.03, -0.3; and - 0.5, - 0.12, 0.4, respectively. The Ki step further divides into two steps: 1) the pre-equilibrium protonation of the inhibitors, Kb step and 2) formation of a negatively charged enzyme-inhibitor Michaelis-Menten complex--virtual inhibition, K'i step. The Ki step has little ortho steric enhancement effect; moreover, the k(c)step is insensitive to the ortho steric effect. The f value of 0.7 for the Ki step indicates that ortho electron-withdrawing substituents of the inhibitors accelerate the inhibition reactions from the ortho polar effect; however, the f value of -0.3 for the k(c)step implies that ortho electron-withdrawing substituents of the inhibitors lessen the inhibition reactions from the ortho polar effect.

Access to Diosgenyl Glycoconjugates via Gold(I)-Catalyzed Etherification of Diosgen-3-yl ortho-Hexynylbenzoate.

PubMed

Zhang, Li; Li, Linfeng; Bai, Shujin; Zhou, Xin; Wang, Peng; Li, Ming

2016-12-02

An efficient protocol for the synthesis of diverse diosgen-3-yl glycoconjugates, a class of novel synthetic analogs of natural saponins of biological significance, has been developed. The method relies on gold(I)-catalyzed etherification of diosgen-3-yl ortho-hexynylbenzoate with stoichiometric sugar alcohols to afford the corresponding glycoconjugates in 38%-99% yields. The reaction involves the preferential attack of hydroxyl groups to the C3 position of homoallylic carbocation intermediate and displays a broad substrate scope and a good functional group tolerance.

Synthesis and Properties of Ortho-Nitro-Fe Complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishra, A.; Mishra, Niyati; Sharma, R.

2011-07-15

Ortho-Nitro-Fe complex (Transition metal complex) has synthesized by chemical route method and properties of made complex has characterized by X-Ray diffraction (XRD), Moessbauer spectroscopy, Fourier transformation infra-red spectroscopy (FTIR) and X-Ray photoelectron spectroscopy (XPS). XRD analysis shows that sample is crystalline in nature and having particle size in the range of few nano meters. Moessbauer spectroscopy at room temperature shows the oxidation state of Iron (central metal ion) after complaxasion. FTIR spectra of the complex confirms the coordination of metal ion with ligand.

Bioinspired organocatalytic aerobic C-H oxidation of amines with an ortho-quinone catalyst.

PubMed

Qin, Yan; Zhang, Long; Lv, Jian; Luo, Sanzhong; Cheng, Jin-Pei

2015-03-20

A simple bioinspired ortho-quinone catalyst for the aerobic oxidative dehydrogenation of amines to imines is reported. Without any metal cocatalysts, the identified optimal ortho-quinone catalyst enables the oxidations of α-branched primary amines and cyclic secondary amines. Mechanistic studies have disclosed the origins of different performances of ortho-quinone vs para-quinone in biomimetic amine oxidations.

Mutagenic activation reduces carcinogenic activity of ortho-aminoazotoluene for mouse liver.

PubMed

Ovchinnikova, L P; Bogdanova, L A; Kaledin, V I

2013-03-01

Pentachlorophenol (aromatic amine and azo stain metabolic stimulation inhibitor) reduced the hepatocarcinogenic activity of 4-aminoazobenzene and reduced that of ortho-aminoazotoluene in suckling mice. Both 4-aminoazobenzene and ortho-aminoazotoluene exhibited mutagenic activity in Ames' test in vitro on S. typhimurium TA 98 strain with activation with liver enzymes; this mutagenic activity was similarly suppressed by adding pentachlorophenol into activation medium. Induction of xenobiotic metabolism enzymes, stimulating the mutagenic activity of ortho-aminoazotoluene, suppressed its carcinogenic effect on mouse liver. Hence, ortho-aminotoluene (the initial compound), but not its mutagenic metabolites, was the direct active hepatocarcinogen for mice.

A comparison study of the Born effective charges and dielectric properties of the cubic, tetragonal, monoclinic, ortho-I, ortho-II and ortho-III phases of zirconia

NASA Astrophysics Data System (ADS)

Zhang, Yan; Chen, Hua-Xin; Duan, Li; Fan, Ji-Bin; Ni, Lei; Ji, Vincent

2018-07-01

Using density-functional perturbation theory, we systematically investigate the Born effective charges and dielectric properties of cubic, tetragonal, monoclinic, ortho-I (Pbca), ortho-II (Pnma) and ortho-III (Pca21) phases of ZrO2. The magnitudes of the Born effective charges of the Zr and oxygen atoms are greater than their nominal ionic valences (+4 for Zr and -2 for oxygen), indicating a strong dynamic charge transfer from Zr atoms to O atoms and a mixed covalent-ionic bonding in six phases of ZrO2. For all six phases of ZrO2, the electronic contributions εij∞ to the static dielectric constant are rather small (range from 5 to 6.5) and neither strongly anisotropic nor strongly dependent on the structural phase, while the ionic contributions εijion to the static dielectric constant are large and not only anisotropic but also dependent on the structural phase. The average dielectric constant εbar0 of the six ZrO2 phases decreases in the sequence of tetragonal, cubic, ortho-II (Pnma), ortho-I (Pbca), ortho-III (Pca21) and monoclinic. So among six phases of ZrO2, the tetragonal and cubic phases are two suitable phases to replace SiO2 as the gate dielectric material in modern integrated-circuit technology. Furthermore, for the tetragonal ZrO2 the best orientation is [100].

Ortho- and para-hydrogen in dense clouds, protoplanets, and planetary atmospheres

NASA Technical Reports Server (NTRS)

Decampli, W. M.; Cameron, A. G. W.; Bodenheimer, P.; Black, D. C.

1978-01-01

If ortho- and para-hydrogen achieve a thermal ratio on dynamical time scales in a molecular hydrogen cloud, then the specific heat is high enough in the temperature range 35-70 K to possibly induce hydrodynamic collapse. The ortho-para ratio in many interstellar cloud fragments is expected to meet this condition. The same may have been true for the primitive solar nebula. Detailed hydrodynamic and hydrostatic calculations are presented that show the effects of the assumed ortho-para ratio on the evolution of Jupiter during its protoplanetary phase. Some possible consequences of a thermalized ortho-para ratio in the atmospheres of the giant planets are also discussed.

Sensitometric properties of Agfa Dentus OrthoLux, Agfa Dentus ST8G, and Kodak Ektavision panoramic radiographic film.

PubMed

Wakoh, M; Nishikawa, K; Kobayashi, N; Farman, A G; Kuroyanagi, K

2001-02-01

The purpose of this study was to compare the sensitometric properties of and visualization of anatomical structures with Agfa OrthoLux green-sensitive panoramic radiographic film, Agfa ST8G green sensitive panoramic radiographic film, and Kodak Ektavision green-sensitive panoramic radiographic film used in combination with an Agfa Ortho Regular 400 imaging screen, Kodak Ektavision imaging screen, and Kodak Lanex Regular imaging screen. The density response and resolution of panoramic radiographic film/intensifying screen combinations was evaluated by means of Hunter and Driffield curves, modulation transfer functions, and noise-equivalent number of quanta. Image clarity of selected anatomical structures was rated independently by 6 oral and maxillofacial radiologists. The ISO speed for the Agfa OrthoLux panoramic radiographic film combinations was the fastest, and the ISO speed for the Kodak Ektavision green-sensitive panoramic radiographic film combinations was the slowest. The average gradient for the Agfa ST8G systems was relatively steep in comparison with those for the other film/screen combinations. The modulation transfer functions for the Kodak Ektavision film were higher than those for the other films, irrespective of the screen combination used, and those for Agfa OrthoLux film were slightly higher than those for Agfa ST8G film. The noise-equivalent number of quanta for the Agfa ST8G film/screen combinations was lower than those for the other film/screen combinations. The noise-equivalent number of quanta for the Kodak Ektavision film/screen combinations was well within the high-frequency range, whereas Agfa OrthoLux combined with either the Kodak Ektavision imaging screen or the Kodak Lanex Regular imaging screen produced a noise-equivalent number of quanta similar to those of the Kodak Ektavision film/screen combinations in the low-frequency range. Agfa OrthoLux was perceived to provide clearer images of the selected anatomical details than Agfa ST8G, and the Agfa OrthoLux/Agfa Ortho Regular 400 combination was not significantly different from the Kodak Ektavision/Kodak Lanex Regular combination in terms of perceived image quality. Agfa OrthoLux is an improvement over Agfa ST8G in film speed, spatial resolution, granularity, and perceived diagnostic image quality. The Agfa OrthoLux/Agfa Ortho Regular 400 combination did not exceed the Kodak Ektavision film/Kodak Ektavision imaging screen combination in resolution, granularity, or perceived image quality.

Absolute configuration and crystal packing chirality for three conglomerate-forming ortho-halogen substituted phenyl glycerol ethers

NASA Astrophysics Data System (ADS)

Bredikhin, Alexander A.; Gubaidullin, Aidar T.; Bredikhina, Zemfira A.

2010-06-01

Three conglomerate-forming ortho-Hal (Hal = Cl, Br, I) substituted phenyl glycerol ethers 1- 3 were investigated by single-crystal X-ray analysis, and the absolute configuration for all substances was established. The molecular structures and crystal packing details for halogen derivatives were compared with the same characteristics for ortho-OCH 3 and ortho-CH 3 analogues. Two different types of crystal packing were evaluated for these very much alike compounds. The interplay of the supramolecular crystal organization chirality sense and the single molecule absolute configuration was demonstrated. Some stabilizing and destabilizing interactions involving the ortho-substituents were revealed. The resolution of rac-2 by entrainment procedure was successfully realized.

The longitudinal orthokeratology research in children (LORIC) in Hong Kong: a pilot study on refractive changes and myopic control.

PubMed

Cho, Pauline; Cheung, Sin Wan; Edwards, Marion

2005-01-01

Myopia is a common ocular disorder, and progression of myopia in children is of increasing concern. Modern overnight orthokeratology (ortho-k) is effective for myopic reduction and has been claimed to be effective in slowing the progression of myopia (myopic control) in children, although scientific evidence for this has been lacking. This 2 year pilot study was conducted to determine whether ortho-k can effectively reduce and control myopia in children. We monitored the growth of axial length (AL) and vitreous chamber depth (VCD) in 35 children (7-12 years of age), undergoing ortho-k treatment and compared the rates of change with 35 children wearing single-vision spectacles from an earlier study (control). For the ortho-k subjects, we also determined the changes in corneal curvature and the relationships with changes of refractive errors, AL and VCD. The baseline spherical equivalent refractive errors (SER), the AL, and VCD of the ortho-k and control subjects were not statistically different. All the ortho-k subjects found post-ortho-k unaided vision acceptable in the daytime. The residual SER at the end of the study was -0.18 +/- 0.69 D (dioptre) and the reduction (less myopic) in SER was 2.09 +/- 1.34 D (all values are mean +/- SD). At the end of 24 months, the increases in AL were 0.29 +/- 0.27 mm and 0.54 +/- 0.27 mm for the ortho-k and control groups, respectively (unpaired t test; p = 0.012); the increases in VCD were 0.23 +/- 0.25 mm and 0.48 +/- 0.26 mm for the ortho-k and control groups, respectively (p = 0.005). There was significant initial corneal flattening in the ortho-k group but no significant relationships were found between changes in corneal power and changes in AL and VCD. Ortho-k can have both a corrective and preventive/control effect in childhood myopia. However, there are substantial variations in changes in eye length among children and there is no way to predict the effect for individual subjects.

Cross-sectional Associations between Exposure to Persistent Organic Pollutants and Leukocyte Telomere Length among U.S. Adults in NHANES, 2001–2002

PubMed Central

Mitro, Susanna D.; Birnbaum, Linda S.; Needham, Belinda L.; Zota, Ami R.

2015-01-01

Background: Exposure to persistent organic pollutants (POPs) such as dioxins, furans, and polychlorinated biphenyls (PCBs) may influence leukocyte telomere length (LTL), a biomarker associated with chronic disease. In vitro research suggests dioxins may bind to the aryl hydrocarbon receptor (AhR) and induce telomerase activity, which elongates LTL. However, few epidemiologic studies have investigated associations between POPs and LTL. Objectives: We examined the association between 18 PCBs, 7 dioxins, and 9 furans and LTL among 1,330 U.S. adults from NHANES 2001–2002. Methods: We created three summed POP metrics based on toxic equivalency factor (TEF), a potency measure including affinity for the AhR: a) non–dioxin-like PCBs (composed of 10 non–dioxin-like PCBs; no AhR affinity and no TEF); b) non-ortho PCBs (composed of 2 non–ortho-substituted PCBs with high TEFs); and c) toxic equivalency (TEQ) (composed of 7 dioxins, 9 furans, 2 non–ortho-substituted PCBs, and 6 mono–ortho-substituted PCBs; weighted by TEF). We tested the association between each metric and LTL using linear regression, adjusting for demographics, blood cell count and distribution, and another metric with a different TEF (i.e., non-ortho PCBs and TEQ adjusted for non–dioxin-like PCBs; non–dioxin-like PCBs adjusted for non-ortho PCBs). Results: In adjusted models, each doubling of serum concentrations of non-ortho PCBs and TEQ was associated with 3.74% (95% CI: 2.10, 5.40) and 5.29% (95% CI: 1.66, 9.05) longer LTLs, respectively. Compared with the lowest quartile, the highest quartile of exposure was associated with 9.16% (95% CI: 2.96, 15.73) and 7.84% (95% CI: –0.53, 16.92) longer LTLs, respectively. Non–dioxin-like PCBs were not associated with LTL. Conclusions: POPs with high TEFs and AhR affinity were associated with longer LTL. Because many dioxin-associated cancers are also associated with longer LTL, these results may provide insight into the mechanisms underlying PCB- and dioxin-related carcinogenesis. Citation: Mitro SD, Birnbaum LS, Needham BL, Zota AR. 2016. Cross-sectional associations between exposure to persistent organic pollutants and leukocyte telomere length among U.S. adults in NHANES, 2001–2002. Environ Health Perspect 124:651–658; http://dx.doi.org/10.1289/ehp.1510187 PMID:26452299

Poly(ortho esters)--from concept to reality.

PubMed

Heller, Jorge; Barr, John

2004-01-01

The development of poly(ortho esters) dates back to the early 1970s, and during that time, four distinct families were developed. These polymers can be prepared by a transesterification reaction or by the addition of polyols to diketene acetals, and it is the latter method that has proven to be preferred one. The latest polymer, now under intense development, incorporates a latent acid segment in the polymer backbone that takes advantage of the acid-labile nature of the ortho ester linkages and allows control over erosion rates. By use of diols having selected chain flexibility, polymers that range from hard, brittle materials to materials that have a gel-like consistency at room temperature can be obtained. Drug release from solid materials will be illustrated with 5-fluorouacil and bovine serum albumin, and drug release from gel-like materials will be illustrated with mepivacaine, now in Phase II clinical trials as a delivery system to treat post-operative pain. A brief summary of preclinical toxicology studies is also presented.

Two new ortho benzoquinones from Uncaria rhynchophylla.

PubMed

Zhang, Qian; Chen, Lei; Hu, Le-Jian; Liu, Wen-Yuan; Feng, Feng; Qu, Wei

2016-03-01

The present study was designed to determine the chemical constituents of the stems and hooks of Uncaria rhynchophylla. The chemical constituents were isolated and purified from CH2Cl2 fraction by chromatography. Their structures were elucidated by spectroscopic analyses. Their cytotoxicity was tested using MTT method. Two new ortho benzoquinones, 3-diethylamino-5-methoxy-1, 2-benzoquinone (1) and 3-ethylamino-5-methoxy-1, 2-benzoquinone (2), together with a known compound isorhynchophyllic acid (3) were isolated from U. rhynchophylla. These compounds were evaluated for their cytotoxicity against cancer cells A549, HepG2 and A2780. Compounds 1 and 2 were new ortho benzoquinones and showed weak antiproliferative activities on A549, HepG2 and A2780 cells. Compound 3 significantly inhibited the proliferation of A549, HepG2 and A2780 cells with IC50 values being 5.8, 12.8 and 11.8 µmol·L(-1), respectively. Copyright © 2016 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Selective collision-induced fragmentation of ortho-hydroxybenzyl-aminated lysyl-containing tryptic peptides.

PubMed

Simon, E S; Papoulias, P G; Andrews, P C

2013-07-30

In protein studies that employ tandem mass spectrometry the manipulation of protonated peptide fragmentation through exclusive dissociation pathways may be preferred in some applications over the comprehensive amide backbone fragmentation that is typically observed. In this study, we characterized the selective cleavage of the side-chain Cζ-Nε bond of peptides with ortho-hydroxybenzyl-aminated lysine residues. Internal lysyl residues of representative peptides were derivatized via reductive amination with ortho-hydroxybenzaldehyde. The modified peptides were analyzed using collision-induced dissociation (CID) on an Orbitrap tandem mass spectrometer. Theoretical calculations using computational methods (density functional theory) were performed to investigate the potential dissociation mechanisms for the Cζ-Nε bond of the derivatized lysyl residue resulting in the formation of the observed product ions. Tandem mass spectra of the derivatized peptide ions exhibit product peaks corresponding to selective cleavage of the side-chain Cζ-Nε bond that links the derivative to lysine. The ortho-hydroxybenzyl derivative is released either as a neutral moiety [C7H6O1] or as a carbocation [C7H7O1](+) through competing pathways (retro-Michael versus Carbocation Elimination (CCE), respectively). The calculated transition state activation barriers indicate that the retro-Michael pathway is kinetically favored over CCE and both are favored over amide cleavage. The application of ortho-hydroxybenzyl amination is a promising peptide derivatization scheme for promoting selective dissociation pathways in the tandem mass spectrometry of protonated peptides. This can be implemented in the rational development of peptide reactive reagents for applications that may benefit from selective fragmentation paths (including crosslinking or MRM reagents). Copyright © 2013 John Wiley & Sons, Ltd.

Comparison of the protein-coding genomes of three deep-sea, sulfur-oxidising bacteria: "Candidatus Ruthia magnifica", "Candidatus Vesicomyosocius okutanii" and Thiomicrospira crunogena.

PubMed

McGill, Susan E; Barker, Daniel

2017-07-20

" Candidatus Ruthia magnifica", "Candidatus Vesicomyosocius okutanii" and Thiomicrospira crunogena are all sulfur-oxidising bacteria found in deep-sea vent environments. Recent research suggests that the two symbiotic organisms, "Candidatus R. magnifica" and "Candidatus V. okutanii", may share common ancestry with the autonomously living species T. crunogena. We used comparative genomics to examine the genome-wide protein-coding content of all three species to explore their similarities. In particular, we used the OrthoMCL algorithm to sort proteins into groups of putative orthologs on the basis of sequence similarity. The OrthoMCL inflation parameter was tuned using biological criteria. Using the tuned value, OrthoMCL delimited 1070 protein groups. 63.5% of these groups contained one protein from each species. Two groups contained duplicate protein copies from all three species. 123 groups were unique to T. crunogena and ten groups included multiple copies of T. crunogena proteins but only single copies from the other species. "Candidatus R. magnifica" had one unique group, and had multiple copies in one group where the other species had a single copy. There were no groups unique to "Candidatus V. okutanii", and no groups in which there were multiple "Candidatus V. okutanii" proteins but only single proteins from the other species. Results align with previous suggestions that all three species share a common ancestor. However this is not definitive evidence to make taxonomic conclusions and the possibility of horizontal gene transfer was not investigated. Methodologically, the tuning of the OrthoMCL inflation parameter using biological criteria provides further methods to refine the OrthoMCL procedure.

Protodeboronation of ortho- and para-phenol boronic acids and application to ortho and meta functionalization of phenols using boronic acids as blocking and directing groups.

PubMed

Lee, Chun-Young; Ahn, Su-Jin; Cheon, Cheol-Hong

2013-12-06

The first metal-free thermal protodeboronation of ortho- and para-phenol boronic acids in DMSO was developed. The protodeboronation was successfully applied to the synthesis of ortho- and meta-functionalized phenols using the boronic acid moiety as a blocking group and a directing group, respectively. Mechanistic studies suggested that this protodeboronation proceeds through the coordination of water to the boron atom followed by σ-bond metathesis.

Quantum rotation of ortho and para-water encapsulated in a fullerene cage

PubMed Central

Beduz, Carlo; Carravetta, Marina; Chen, Judy Y.-C.; Concistrè, Maria; Denning, Mark; Frunzi, Michael; Horsewill, Anthony J.; Johannessen, Ole G.; Lawler, Ronald; Lei, Xuegong; Levitt, Malcolm H.; Li, Yongjun; Mamone, Salvatore; Murata, Yasujiro; Nagel, Urmas; Nishida, Tomoko; Ollivier, Jacques; Rols, Stéphane; Rõõm, Toomas; Sarkar, Riddhiman; Turro, Nicholas J.; Yang, Yifeng

2012-01-01

Inelastic neutron scattering, far-infrared spectroscopy, and cryogenic nuclear magnetic resonance are used to investigate the quantized rotation and ortho–para conversion of single water molecules trapped inside closed fullerene cages. The existence of metastable ortho-water molecules is demonstrated, and the interconversion of ortho-and para-water spin isomers is tracked in real time. Our investigation reveals that the ground state of encapsulated ortho water has a lifted degeneracy, associated with symmetry-breaking of the water environment. PMID:22837402

BEHAVIORAL ASSESSMENTS OF ADULTS RATS EXPOSED PERINATALLY TO PCB153.

EPA Science Inventory

Ortho-substituted polychlorinated biphenyl (PCB) congeners are more neurotoxic in vitro than are non-ortho-substituted PCB congeners. We selected PCB153, a common ortho-substituted PCB congener, to evaluate the neurobehavioral toxicity of this class of PCBs in vivo. Pregnant fema...

Sequence-defined oligo(ortho-arylene) foldamers derived from the benzannulation of ortho(arylene ethynylene)s† †Electronic supplementary information (ESI) available. CCDC 1483959–1483967. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc02520j Click here for additional data file. Click here for additional data file.

PubMed Central

Lehnherr, Dan; Chen, Chen; Pedramrazi, Zahra; DeBlase, Catherine R.; Alzola, Joaquin M.; Keresztes, Ivan; Lobkovsky, Emil B.

2016-01-01

A Cu-catalyzed benzannulation reaction transforms ortho(arylene ethynylene) oligomers into ortho-arylenes. This approach circumvents iterative Suzuki cross-coupling reactions previously used to assemble hindered ortho-arylene backbones. These derivatives form helical folded structures in the solid-state and in solution, as demonstrated by X-ray crystallography and solution-state NMR analysis. DFT calculations of misfolded conformations are correlated with variable-temperature 1H and EXSY NMR to reveal that folding is cooperative and more favorable in halide-substituted naphthalenes. Helical ortho-arylene foldamers with specific aromatic sequences organize functional π-electron systems into arrangements ideal for ambipolar charge transport and show preliminary promise for the surface-mediated synthesis of structurally defined graphene nanoribbons. PMID:28567248

Building Area Extraction from Polarimetric SAR Data via Stationarity Detection and Circular-Pol Correlation Coefficient

NASA Astrophysics Data System (ADS)

Xiang, Deliang; Su, Yi; Ban, Yifeng

2015-04-01

Since the buildings have complex geometries and may be misclassified as forests or mountains with volume scattering due to the significant cross-pol backscatter and lack reflection symmetry, especially the slant-oriented buildings, building area extraction is a challenging problem. In this paper, the time-frequency decomposition technique is adopted to acquire subaperture images, which correspond to the same scene responses under different azimuthal look angles. Stationarity detection approach with polarimetric G0 distribution is proposed to extract ortho-orientedbuildings and the circular polarization correlation coefficient is optimal in characterizing slant-oriented buildings. We test the aforementioned method using ESAR image with L-band. The results demonstrate that the proposed method can effectively extract both ortho-oriented and slant-oriented buildings and the overall detection accuracy as well as kappa value is 10%-20% higher than the compared methods.

Microwave-Based Reaction Screening: Tandem Retro-Diels-Alder/Diels-Alder Cycloadditions of ortho-Quinol Dimers

PubMed Central

Dong, Suwei; Cahill, Kath arine J.; Kang, Moon -Il; Colburn, Nancy H.; Henrich, Curtis J.; Wilson, Jennifer A.; Beutler, John A.; Johnson, Richard P.; Porco, John A.

2011-01-01

We have accomplished a parallel screen of cycloaddition partners for ortho-quinols utilizing a plate-based microwave system. Microwave irradiation improves the efficiency of retro-Diels-Alder/Diels-Alder cascades of ortho-quinol dimers which generally proceed in a diastereoselective fashion. Computational studies indicate that asynchronous transition states are favored in Diels-Alder cycloadditions of ortho-quinols. Subsequent biological evaluation of a collection of cycloadducts has identified an inhibitor of activator protein-1 (AP-1), an oncogenic transcription factor. PMID:21942286

A centroid molecular dynamics study of liquid para-hydrogen and ortho-deuterium.

PubMed

Hone, Tyler D; Voth, Gregory A

2004-10-01

Centroid molecular dynamics (CMD) is applied to the study of collective and single-particle dynamics in liquid para-hydrogen at two state points and liquid ortho-deuterium at one state point. The CMD results are compared with the results of classical molecular dynamics, quantum mode coupling theory, a maximum entropy analytic continuation approach, pair-product forward- backward semiclassical dynamics, and available experimental results. The self-diffusion constants are in excellent agreement with the experimental measurements for all systems studied. Furthermore, it is shown that the method is able to adequately describe both the single-particle and collective dynamics of quantum liquids. (c) 2004 American Institute of Physics

Determination of the ortho to para ratio of H2Cl+ and H2O+ from submillimeter observations.

PubMed

Gerin, Maryvonne; de Luca, Massimo; Lis, Dariusz C; Kramer, Carsten; Navarro, Santiago; Neufeld, David; Indriolo, Nick; Godard, Benjamin; Le Petit, Franck; Peng, Ruisheng; Phillips, Thomas G; Roueff, Evelyne

2013-10-03

The opening of the submillimeter sky with the Herschel Space Observatory has led to the detection of new interstellar molecular ions, H2O(+), H2Cl(+), and HCl(+), which are important intermediates in the synthesis of water vapor and hydrogen chloride. In this paper, we report new observations of H2O(+) and H2Cl(+) performed with both Herschel and ground-based telescopes, to determine the abundances of their ortho and para forms separately and derive the ortho-to-para ratio. At the achieved signal-to-noise ratio, the observations are consistent with an ortho-to-para ratios of 3 for both H2O(+) and H2Cl(+), in all velocity components detected along the lines-of-sight to the massive star-forming regions W31C and W49N. We discuss the mechanisms that contribute to establishing the observed ortho-to-para ratio and point to the need for a better understanding of chemical reactions, which are important for establishing the H2O(+) and H2Cl(+) ortho-to-para ratios.

Electron Spin Polarization Transfer to ortho-H2 by Interaction of para-H2 with Paramagnetic Species: A Key to a Novel para → ortho Conversion Mechanism.

PubMed

Terenzi, Camilla; Bouguet-Bonnet, Sabine; Canet, Daniel

2015-05-07

We report that at ambient temperature and with 100% enriched para-hydrogen (p-H2) dissolved in organic solvents, paramagnetic spin catalysis of para → ortho hydrogen conversion is accompanied at the onset by a negative ortho-hydrogen (o-H2) proton NMR signal. This novel finding indicates an electron spin polarization transfer, and we show here that this can only occur if the H2 molecule is dissociated upon its transient adsorption by the paramagnetic catalyst. Following desorption, o-H2 is created until the thermodynamic equilibrium is reached. A simple theory confirms that in the presence of a static magnetic field, the hyperfine coupling between unpaired electrons and nuclear spins is responsible for the observed polarization transfer. Owing to the negative electron gyromagnetic ratio, this explains the experimental results and ascertains an as yet unexplored mechanism for para → ortho conversion. Finally, we show that the recovery of o-H2 magnetization toward equilibrium can be simply modeled, leading to the para → ortho conversion rate.

Conversion rate of para-hydrogen to ortho-hydrogen by oxygen: implications for PHIP gas storage and utilization.

PubMed

Wagner, Shawn

2014-06-01

To determine the storability of para-hydrogen before reestablishment of the room temperature thermal equilibrium mixture. Para-hydrogen was produced at near 100% purity and mixed with different oxygen quantities to determine the rate of conversion to the thermal equilibrium mixture of 75: 25% (ortho: para) by detecting the ortho-hydrogen (1)H nuclear magnetic resonance using a 9.4 T imager. The para-hydrogen to ortho-hydrogen velocity constant, k, near room temperature (292 K) was determined to be 8.27 ± 1.30 L/mol · min(-1). This value was calculated utilizing four different oxygen fractions. Para-hydrogen conversion to ortho-hydrogen by oxygen can be minimized for long term storage with judicious removal of oxygen contamination. Prior calculated velocity rates were confirmed demonstrating a dependence on only the oxygen concentration.

Exploitation of the complexation reaction of ortho-dihydroxylated anthocyanins with aluminum(III) for their quantitative spectrophotometric determination in edible sources.

PubMed

Bernal, Freddy A; Orduz-Diaz, Luisa L; Coy-Barrera, Ericsson

2015-10-15

Anthocyanins are natural pigments known for their color and antioxidant activity. These properties allow their use in various fields, including food and pharmaceutical ones. Quantitative determination of anthocyanins had been performed by non-specific methods that limit the accuracy and reliability of the results. Therefore, a novel, simple spectrophotometric method for the anthocyanins quantification based on a formation of blue-colored complexes by the known reaction between catechol- and pyrogallol-containing anthocyanins and aluminum(III) is presented. The method demonstrated to be reproducible, repetitive (RSD<1.5%) and highly sensitive to ortho-dihydroxylated anthocyanins (LOD = 0.186 μg/mL). Compliance with Beer's law was also evident in a range of concentrations (2-16 μg/mL for cyanidin 3-O-glucoside). Good recoveries (98.8-103.3%) were calculated using anthocyanin-rich plant samples. The described method revealed direct correlation to pH differential method results for several common anthocyanin-containing fruits indicating its great analytical potential. The presented method was successfully validated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Developing tools for digital radar image data evaluation

NASA Technical Reports Server (NTRS)

Domik, G.; Leberl, F.; Raggam, J.

1986-01-01

The refinement of radar image analysis methods has led to a need for a systems approach to radar image processing software. Developments stimulated through satellite radar are combined with standard image processing techniques to create a user environment to manipulate and analyze airborne and satellite radar images. One aim is to create radar products for the user from the original data to enhance the ease of understanding the contents. The results are called secondary image products and derive from the original digital images. Another aim is to support interactive SAR image analysis. Software methods permit use of a digital height model to create ortho images, synthetic images, stereo-ortho images, radar maps or color combinations of different component products. Efforts are ongoing to integrate individual tools into a combined hardware/software environment for interactive radar image analysis.

Influence of Adhesives and Methods of Enamel Pretreatment on the Shear Bond Strength of Orthodontic Brackets

PubMed Central

Jurišić, Sanja; Jurišić, Gordan

2015-01-01

Aim The objective of present study was to examine influence of adhesives and methods of enamel pretreatment on the shear bond strength (SBS) of orthodontic brackets. The adhesives used were resin-reinforced glass ionomer cements-GIC (Fuji Ortho LC) and composite resin (Transbond XT). Material and Methods The experimental sample consisted of 80 extracted human first premolars. The sample was divided into four equal groups, and the metal brackets were bonded with different enamel pretreatments by using two adhesives: group A-10% polyacrylic acid; Fuji Ortho LC, group B–37% phosphoric acid; Fuji Ortho LC, group C–self etching primer; Transbond XT, group D–37% phosphoric acid, primer; Transbond XT. SBS of brackets was measured. After debonding of brackets, the adhesive remnant index (ARI) was evaluated. Results After the statistical analysis of the collected data was performed (ANOVA; Sheffe post-hoc test), the results showed that significantly lower SBS of the group B was found in relation to the groups C (p=0.031) and D (p=0.026). The results of ARI were similar in all testing groups and it was not possible to determine any statistically significant difference of the ARI (Chi- square test) between all four experimental groups. Conclusion The conclusion is that the use of composite resins material with appropriate enamel pretreatment according to manufacturer’s recommendation is the “gold standard” for brackets bonding for fixed orthodontic appliances. PMID:27688410

Novel pH-Sensitive Cationic Lipids with Linear Ortho Ester Linkers for Gene Delivery

PubMed Central

Chen, Haigang; Zhang, Huizhen; Thor, Der; Rahimian, Roshanak; Guo, Xin

2012-01-01

In an effort to develop pH-sensitive lipoplexes for efficient gene delivery, we report three novel cationic lipids containing a linear ortho ester linker that conjugates either the headgroup (Type I) or one hydrocarbon chain (Type II) with the rest of the lipid molecule. The cationic lipids carry either an iodide or a chloride counterion. Compared to our previously reported cyclic ortho ester linker, the linear ortho ester linker facilitated the construction of cationic liposomes and lipoplexes with different helper lipids. The chloride counterion not only facilitated the hydration of the lipid films during liposome construction, but also enhanced the hydrolysis of the ortho ester linker in the lipoplexes. After incubation at endosomal pH 5.5, the Type I lipoplexes aggregated and destabilized the endosome-mimicking model liposomes, but not the Type II lipoplexes. The helper lipids (DOPE or cholesterol) of the lipoplexes enhanced the pH-sensitivity of the Type I lipoplexes. In CV-1 cells (monkey kidney fibroblast), the Type I ortho ester-based lipoplexes, especially those with the chloride counterion, significantly improved the gene transfection efficiency, in some cases by more than 100 fold, compared to their pH-insensitive counterparts consisting of DOTAP. The gene transfection efficiency of the ortho ester-based lipoplexes was well correlated with their rate of aggregation and membrane destabilization in response to the endosomal pH 5.5. PMID:22480493

The Mass Spectrometric Ortho Effect Studied for All 209 PCB Congeners

EPA Science Inventory

A method for the determination of polychlorinated biphenyls (PCBs) in caulk was developed; with application to a set of caulk and window glazing material samples. This method was evaluated by analyzing a combination of 47 samples of caulk, glazing materials, and including quality...

Quantitation of ortho-Cresyl Phosphate Adducts to Butyrylcholinesterase in Human Serum by Immunomagnetic-UHPLC-MS/MS

PubMed Central

Johnson, Darryl; Carter, Melissa D.; Crow, Brian S.; Isenberg, Samantha L.; Graham, Leigh Ann; Erol, H. Akin; Watson, Caroline M.; Pantazides, Brooke G.; van der Schans, Marcel J.; Langenberg, Jan P.; Noort, Daan; Blake, Thomas A.; Thomas, Jerry D.; Johnson, Rudolph C.

2017-01-01

Tri-ortho-cresyl phosphate (ToCP) is an anti-wear, flame retardant additive used in industrial lubricants, hydraulic fluids, and gasoline. The neurotoxic effects of ToCP arise from the liver-activated metabolite 2-(o-cresyl)-4H-1,3,2-benzodioxaphosphoran-2-one (cresyl saligenin phosphate or CBDP), which inhibits esterase enzymes including butyrylcholinesterase (BChE). Following BChE adduction, CBDP undergoes hydrolysis to form the aged adduct ortho-cresyl phosphoserine (oCP-BChE), thus providing a biomarker of CBDP exposure. Previous studies have identified ToCP in aircraft cabin and cockpit air, but assessing human exposure has been hampered by the lack of a laboratory assay to confirm exposure. This work presents the development of an immunomagnetic-UHPLC-MS/MS method for the quantitation of unadducted BChE and the long-term CBDP biomarker, oCP-BChE, in human serum. The method has a reportable range from 2.0 ng/mL to 150 ng/mL, which is consistent with the sensitivity of methods used to detect organophosphorus nerve agent protein adducts. The assay demonstrated high intraday and interday accuracy (≥ 85%) and precision (RSD ≤ 15%) across the calibration range. The method was developed for future analyses of potential human exposure to CBDP. Analysis of human serum inhibited in vitro with CBDP demonstrated that the oCP-BChE adduct was stable for at least 72 hours at 4, 22 and 37 °C. Compared to a previously reported assay, this method requires 75% less sample volume, reduces analysis time by a factor of 20, and demonstrates a 3-fold improvement in sensitivity. PMID:26149113

An ortho-substituted BIPHEP ligand and its applications in Rh-catalyzed hydrogenation of cyclic enamides.

PubMed

Tang, Wenjun; Chi, Yongxiang; Zhang, Xumu

2002-05-16

[reaction: see text] An ortho-substituted BIPHEP ligand, o-Ph-hexaMeO-BIPHEP (1), is designed and synthesized. Compared with chiral biaryl phosphines without ortho substituents such as BINAP and MeO-BIPHEP, o-Ph-hexaMeO-BIPHEP shows higher enantioselectivities in Rh-catalyzed hydrogenation of cyclic enamides.

Iridium-catalysed ortho-H/D and -H/T exchange under basic conditions: C-H activation of unprotected tetrazoles.

PubMed

Kerr, William J; Lindsay, David M; Reid, Marc; Atzrodt, Jens; Derdau, Volker; Rojahn, Patrick; Weck, Remo

2016-05-10

The first examples of selective ortho-directed C-H activation with unprotected 2-aryltetrazoles are described. A new base-assisted protocol for iridium(i) hydrogen isotope exchange catalysis allows access to ortho-deuterated and tritiated tetrazoles, including the tetrazole-containing pharmaceutical, Valsartan. Preliminary mechanistic studies are also presented.

Boosting effect of ortho-propenyl substituent on the antioxidant activity of natural phenols.

PubMed

Marteau, Clémentine; Guitard, Romain; Penverne, Christophe; Favier, Dominique; Nardello-Rataj, Véronique; Aubry, Jean-Marie

2016-04-01

Seven new antioxidants derived from natural or synthetic phenols have been designed as alternatives to BHT and BHA antioxidants. Influence of various substituents at the ortho, meta and para positions of the aromatic core of phenols on the bond dissociation enthalpy of the ArO-H bond was evaluated using a DFT method B3LYP/6-311++G(2d,2p)//B3LYP/6-311G(d,p). This prediction highlighted the ortho-propenyl group as the best substituent to decrease the bond dissociation enthalpy (BDE) value. The rate constants of hydrogen transfer from these phenols to DPPH radical in a non-polar and non-protic solvent have been measured and were found to be in agreement with the BDE calculations. For o-propenyl derivatives from 2-tert-butyl-4-methylphenol, BHA, creosol, isoeugenol and di-o-propenyl p-cresol, fewer radicals were trapped by a single phenol molecule, i.e. a lower stoichiometric number. Reaction mechanisms involving the evolution of the primary phenoxyl radical ArO are proposed to rationalise these effects. Copyright © 2015 Elsevier Ltd. All rights reserved.

True Ortho Generation of Urban Area Using High Resolution Aerial Photos

NASA Astrophysics Data System (ADS)

Hu, Yong; Stanley, David; Xin, Yubin

2016-06-01

The pros and cons of existing methods for true ortho generation are analyzed based on a critical literature review for its two major processing stages: visibility analysis and occlusion compensation. They process frame and pushbroom images using different algorithms for visibility analysis due to the need of perspective centers used by the z-buffer (or alike) techniques. For occlusion compensation, the pixel-based approach likely results in excessive seamlines in the ortho-rectified images due to the use of a quality measure on the pixel-by-pixel rating basis. In this paper, we proposed innovative solutions to tackle the aforementioned problems. For visibility analysis, an elevation buffer technique is introduced to employ the plain elevations instead of the distances from perspective centers by z-buffer, and has the advantage of sensor independency. A segment oriented strategy is developed to evaluate a plain cost measure per segment for occlusion compensation instead of the tedious quality rating per pixel. The cost measure directly evaluates the imaging geometry characteristics in ground space, and is also sensor independent. Experimental results are demonstrated using aerial photos acquired by UltraCam camera.

Where does the electron go? The nature of ortho/para and meta group directing in electrophilic aromatic substitution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Shubin, E-mail: shubin@email.unc.edu

Electrophilic aromatic substitution as one of the most fundamental chemical processes is affected by atoms or groups already attached to the aromatic ring. The groups that promote substitution at the ortho/para or meta positions are, respectively, called ortho/para and meta directing groups, which are often characterized by their capability to donate electrons to or withdraw electrons from the ring. Though resonance and inductive effects have been employed in textbooks to explain this phenomenon, no satisfactory quantitative interpretation is available in the literature. Here, based on the theoretical framework we recently established in density functional reactivity theory (DFRT), where electrophilicity andmore » nucleophilicity are simultaneously quantified by the Hirshfeld charge, the nature of ortho/para and meta group directing is systematically investigated for a total of 85 systems. We find that regioselectivity of electrophilic attacks is determined by the Hirshfeld charge distribution on the aromatic ring. Ortho/para directing groups have most negative charges on the ortho/para positions, while meta directing groups often possess the largest negative charge on the meta position. Our results do not support that ortho/para directing groups are electron donors and meta directing groups are electron acceptors. Most neutral species we studied here are electron withdrawal in nature. Anionic systems are always electron donors. There are also electron donors serving as meta directing groups. We predicted ortho/para and meta group directing behaviors for a list of groups whose regioselectivity is previously unknown. In addition, strong linear correlations between the Hirshfeld charge and the highest occupied molecular orbital have been observed, providing the first link between the frontier molecular orbital theory and DFRT.« less

Decalcification prevention around orthodontic brackets bonded to bleached enamel using different topical agents.

PubMed

Msallam, Ferial Ahmed; Grawish, Mohammed El-Awady; Hafez, Ahmad Mohammed; Abdelnaby, Yasser Lotfy

2017-12-01

The present study was conducted to evaluate the effect of different topical agents utilized for prevention of enamel decalcification around orthodontic brackets bonded to bleached and non-bleached enamel. Human maxillary premolars (n = 120) were divided into two equal groups. Teeth in group I were left without bleaching while those in group II were bleached with Vivastyle gel. Metal brackets were bonded to all the teeth using light-cured adhesive. Each group was divided into six equal subgroups (A, B, C, D, E, and F). In subgroup A, no material was applied (control). In subgroups B, C, D, E, and F, the following materials were applied respectively: Profluorid varnish, Enamel Pro Varnish, Ortho-Choice Ortho-Coat, GC Tooth Mousse, and GC MI Paste Plus. All teeth were cycled in a demineralization solution/artificial saliva for 15 days. Laser fluorescence was used to measure the level of enamel mineralization. The data were statistically analyzed. Regarding the non-bleaching subgroups, all studied material revealed significant demineralization reduction in comparison to the control subgroup (P < 0.05). Ortho-Choice Ortho-Coat revealed the highest significant effect while GC Tooth Mousse showed the least effect. In bleached subgroups, Profluorid varnish, Enamel Pro Varnish, and Ortho-Choice Ortho-Coat significantly reduced demineralization (P < 0.05) while either GC MI Paste Plus or GC Tooth Mousse had no significant effects (P > 0.05). Ortho-Choice Ortho-Coat, and Profluorid and Enamel Pro varnishes could be utilized successfully to reduce enamel demineralization around brackets bonded to either bleached or non-bleached enamel. GC MI Paste Plus and GC Tooth Mousse were effective only in non-bleached enamel.

Hydrogen adsorption on two catalysts for the ortho- to parahydrogen conversion: Cr-doped silica and ferric oxide gel.

PubMed

Hartl, Monika; Gillis, Robert Chad; Daemen, Luke; Olds, Daniel P; Page, Katherine; Carlson, Stefan; Cheng, Yongqiang; Hügle, Thomas; Iverson, Erik B; Ramirez-Cuesta, A J; Lee, Yongjoong; Muhrer, Günter

2016-06-29

Molecular hydrogen exists in two spin-rotation coupled states: parahydrogen and orthohydrogen. Due to the variation of energy with rotational level, the occupation of ortho- and parahydrogen states is temperature dependent, with parahydrogen being the dominant species at low temperatures. The equilibrium at 20 K (99.8% parahydrogen) can be reached by natural conversion only after a lengthy process. With the use of a suitable catalyst, this process can be shortened significantly. Two types of commercial catalysts currently being used for ortho- to parahydrogen conversion are: iron(iii) oxide (Fe2O3, IONEX®), and chromium(ii) oxide doped silica catalyst (CrO·SiO2, OXISORB®). We investigate the interaction of ortho- and parahydrogen with the surfaces of these ortho-para conversion catalysts using neutron vibrational spectroscopy. The catalytic surfaces have been characterized using X-ray absorption fine structure (XAFS) and X-ray/neutron pair distribution function measurements.

Probes for narcotic receptor mediated phenomena. 43. Synthesis of the ortho-a and para-a, and improved synthesis and optical resolution of the ortho-b and para–b oxide-bridged phenylmorphans: Compounds with moderate to low opioid-receptor affinity

PubMed Central

Li, Feng; Folk, John E.; Cheng, Kejun; Kurimura, Muneaki; Deck, Jason A.; Deschamps, Jeffrey R.; Rothman, Richard B.; Dersch, Christina M.; Jacobson, Arthur E.; Rice, Kenner C.

2011-01-01

N-Phenethyl-substituted ortho-a and para-a oxide-bridged phenylmorphans have been obtained through an improved synthesis and their binding affinity examined at the various opioid receptors. Although the N-phenethyl substituent showed much greater affinity for μ- and κ-opioid receptors than their N-methyl relatives (e.g., Ki = 167 nM and 171 nM at μ- and κ-receptors vs >2800 and 7500 nM for the N-methyl ortho-a oxide-bridged phenylmorphan), the a-isomers were not examined further because of their relatively low affinity. The N-phenethyl substituted ortho-b and para-b oxide-bridged phenylmorphans were also synthesized and their enantiomers were obtained using supercritical fluid chromatography. Of the four enantiomers, only the (+)-ortho-b isomer had moderate affinity for μ- and κ-receptors (Ki = 49 and 42 nM, respectively, and it was found to also have moderate μ- and κ-opioid antagonist activity in the [35S]GTP-γ-S assay (Ke = 31 and 26 nM). PMID:21684752

Adaptation of the ORTHO-15 test to Polish women and men.

PubMed

Brytek-Matera, Anna; Krupa, Magdalena; Poggiogalle, Eleonora; Donini, Lorenzo Maria

2014-03-01

There is a lack of Polish tools to measure behaviour related to orthorexia nervosa. The purpose of the present study was to validate the Polish version of the ORTHO-15 test. 341 women and 59 men (N = 400) were recruited, whose age ranged from 18 to 35 years. Mean age was 23.09 years (SD = 3.14) in women and 24.02 years (SD = 3.87) in men. The ORTHO-15 test and the EAT-26 test were used in the present study. Factor analysis (exploratory and confirmatory analysis) was used in the present study. Exploratory factor analysis performed on the initial 15 items from a random split half of the study group suggested a nine-item two-factor structure. Confirmatory factor analysis performed on the second randomly selected half of the study group supported this two-factor structure of the ORTHO-15 test. The Polish version of the ORTHO-15 test demonstrated an internal consistency (Cronbach's alpha) equal to 0.644. The Polish version of the ORTHO-15 test is a reliable and valuable instrument to assess obsessive attitudes related to healthy and proper nutrition in Polish female and male population.

Influence of Adhesives and Methods of Enamel Pretreatment on the Shear Bond Strength of Orthodontic Brackets.

PubMed

Jurišić, Sanja; Jurišić, Gordan; Jurić, Hrvoje

2015-12-01

The objective of present study was to examine influence of adhesives and methods of enamel pretreatment on the shear bond strength (SBS) of orthodontic brackets. The adhesives used were resin-reinforced glass ionomer cements-GIC (Fuji Ortho LC) and composite resin (Transbond XT). The experimental sample consisted of 80 extracted human first premolars. The sample was divided into four equal groups, and the metal brackets were bonded with different enamel pretreatments by using two adhesives: group A-10% polyacrylic acid; Fuji Ortho LC, group B-37% phosphoric acid; Fuji Ortho LC, group C-self etching primer; Transbond XT, group D-37% phosphoric acid, primer; Transbond XT. SBS of brackets was measured. After debonding of brackets, the adhesive remnant index (ARI) was evaluated. After the statistical analysis of the collected data was performed (ANOVA; Sheffe post-hoc test), the results showed that significantly lower SBS of the group B was found in relation to the groups C (p=0.031) and D (p=0.026). The results of ARI were similar in all testing groups and it was not possible to determine any statistically significant difference of the ARI (Chi- square test) between all four experimental groups. The conclusion is that the use of composite resins material with appropriate enamel pretreatment according to manufacturer's recommendation is the "gold standard" for brackets bonding for fixed orthodontic appliances.

Reducing phosphorus loss in tile water with managed drainage in a claypan soil.

PubMed

Nash, Patrick R; Nelson, Kelly A; Motavalli, Peter P; Nathan, Manjula; Dudenhoeffer, Chris

2015-03-01

Installing subsurface tile drain systems in poorly drained claypan soils to improve corn ( L.) yields could potentially increase environmental phosphorus (P) loss through the tile drainage system. The objectives of the study were to quantify the average concentration and loss of ortho-P in tile drain water from a claypan soil and to determine whether managed subsurface drainage (MD) could reduce ortho-P loss in tile water compared with free subsurface drainage (FD). Flow-weighted ortho-P concentration in the tile water was significantly lower with MD (0.09 mg L) compared with that of FD (0.15 mg L). Ortho-P loss in the tile water of this study was reduced with MD (36 g ha) by 80% compared with FD (180 g ha). Contrary to previous research, reduced ortho-P loss observed over the 4-yr study was not solely due to the reduced amount of water drained annually (63%) with MD compared with FD. During the spring period, when flow was similar between MD and FD, the concentration of ortho-P in the tile water generally was lower with MD compared with FD, which resulted in significantly less ortho-P loss with MD. We speculate that MD's ability to conserve water during the dry summer months increased corn's uptake of water and P, which reduced the amount of P available for leaching loss in the subsequent springs. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Mechanisms of Decreased Moisture Uptake in ortho- Methylated Di(Cyanate Esters)

DTIC Science & Technology

2014-10-01

Distribution A: Approved for public release; distribution is unlimited. 1 Mechanisms of Decreased Moisture Uptake in ortho- Methylated Di(Cyanate...when analogous networks containing a single methyl group ortho- to each aryl- cyanurate linkage were prepared by reduction and acid-catalyzed coupling...of salicylic acid followed by treatment with cyanogen bromide and subsequent cyclotrimerization. The differences in water uptake were observed

GIS based Cadastral level Forest Information System using World View-II data in Bir Hisar (Haryana)

NASA Astrophysics Data System (ADS)

Mothi Kumar, K. E.; Singh, S.; Attri, P.; Kumar, R.; Kumar, A.; Sarika; Hooda, R. S.; Sapra, R. K.; Garg, V.; Kumar, V.; Nivedita

2014-11-01

Identification and demarcation of Forest lands on the ground remains a major challenge in Forest administration and management. Cadastral forest mapping deals with forestlands boundary delineation and their associated characterization (forest/non forest). The present study is an application of high resolution World View-II data for digitization of Protected Forest boundary at cadastral level with integration of Records of Right (ROR) data. Cadastral vector data was generated by digitization of spatial data using scanned mussavies in ArcGIS environment. Ortho-images were created from World View-II digital stereo data with Universal Transverse Mercator coordinate system with WGS 84 datum. Cadastral vector data of Bir Hisar (Hisar district, Haryana) and adjacent villages was spatially adjusted over ortho-image using ArcGIS software. Edge matching of village boundaries was done with respect to khasra boundaries of individual village. The notified forest grids were identified on ortho-image and grid vector data was extracted from georeferenced cadastral data. Cadastral forest boundary vectors were digitized from ortho-images. Accuracy of cadastral data was checked by comparison of randomly selected geo-coordinates points, tie lines and boundary measurements of randomly selected parcels generated from image data set with that of actual field measurements. Area comparison was done between cadastral map area, the image map area and RoR area. The area covered under Protected Forest was compared with ROR data and within an accuracy of less than 1 % from ROR area was accepted. The methodology presented in this paper is useful to update the cadastral forest maps. The produced GIS databases and large-scale Forest Maps may serve as a data foundation towards a land register of forests. The study introduces the use of very high resolution satellite data to develop a method for cadastral surveying through on - screen digitization in a less time as compared to the old fashioned cadastral parcel boundaries surveying method.

Development of Total Knee Replacement Digital Templating Software

NASA Astrophysics Data System (ADS)

Yusof, Siti Fairuz; Sulaiman, Riza; Thian Seng, Lee; Mohd. Kassim, Abdul Yazid; Abdullah, Suhail; Yusof, Shahril; Omar, Masbah; Abdul Hamid, Hamzaini

In this study, by taking full advantage of digital X-ray and computer technology, we have developed a semi-automated procedure to template knee implants, by making use of digital templating method. Using this approach, a software system called OrthoKneeTMhas been designed and developed. The system is to be utilities as a study in the Department of Orthopaedic and Traumatology in medical faculty, UKM (FPUKM). OrthoKneeTMtemplating process employs uses a technique similar to those used by many surgeons, using acetate templates over X-ray films. Using template technique makes it easy to template various implant from every Implant manufacturers who have with a comprehensive database of templates. The templating functionality includes, template (knee) and manufactures templates (Smith & Nephew; and Zimmer). From an image of patient x-ray OrthoKneeTMtemplates help in quickly and easily reads to the approximate template size needed. The visual templating features then allow us quickly review multiple template sizes against the X-ray and thus obtain the nearly precise view of the implant size required. The system can assist by templating on one patient image and will generate reports that can accompany patient notes. The software system was implemented in Visual basic 6.0 Pro using the object-oriented techniques to manage the graphics and objects. The approaches for image scaling will be discussed. Several of measurement in orthopedic diagnosis process have been studied and added in this software as measurement tools features using mathematic theorem and equations. The study compared the results of the semi-automated (using digital templating) method to the conventional method to demonstrate the accuracy of the system.

Cooling by conversion of para to ortho-hydrogen

NASA Technical Reports Server (NTRS)

Sherman, A. (Inventor)

1983-01-01

The cooling capacity of a solid hydrogen cooling system is significantly increased by exposing vapor created during evaporation of a solid hydrogen mass to a catalyst and thereby accelerating the endothermic para-to-ortho transition of the vapor to equilibrium hydrogen. Catalyst such as nickel, copper, iron or metal hydride gels of films in a low pressure drop catalytic reactor are suitable for accelerating the endothermic para-to-ortho conversion.

Detection of the MW Transition Between Ortho and Para States

NASA Astrophysics Data System (ADS)

Kanamori, Hideto; Dehghani, Zeinab Tafti; Mizoguchi, Asao; Endo, Yasuki

2017-06-01

Thorough the detailed analysis of the hyperfine resolved rotational transitions, we have been pointed out that there exists not a little interaction between ortho and para states in the molecular Hamiltonian of S_2Cl_2. Using the ortho-para mixed molecular wavefunctions derived from the Hamiltonian, we calculated the transition moment and frequency of the ortho-para forbidden transitions in the cm- and mm-wave region, and picked up some promising candidate transitions for the spectroscopic detection. In the experiment, the S_2Cl_2 vapor with Ar buffer gas in a supersonic jet condition was used with FTMW spectrometer at National Chiao Tung University. As a result, seven hyperfine resolved rotational transitions in the cm-wave region were detected as the ortho-para transition at the predicted frequency within the experimental error range. The observed intensity was 10^{-3} smaller than that of an allowed transition, which is also consistent with the prediction. This is the first time the electric dipole transition between ortho and para states has been detected in a free isolated molecule. A. Mizoguchi, S. Ota, H. Kanamori, Y. Sumiyoshi, and Y. Endo, J. Mol. Spectrosc, 250, 86 (2008) Z. T. Dehghani, S. Ota, A. Mizoguchi and H. Kanamori, J. Phys. Chem. A, 117(39), 10041, (2013)

Variations in surface roughness of seven orthodontic archwires: an SEM-profilometry study

PubMed Central

Rakhshan, Vahid; Pousti, Maryam; Rahimi, Hajir; Shariati, Mahsa; Aghamohamadi, Bahareh

2012-01-01

Objective The purpose of this study was to evaluate the surface roughness (SR) of 2 types of orthodontic archwires made by 4 different manufacturers. Methods This in vitro experimental study was conducted on 35 specimens of 7 different orthodontic archwires, namely, 1 nickel-titanium (NiTi) archwire each from the manufacturers American Orthodontics, OrthoTechnology, All-Star Orthodontics, and Smart Technology, and 1 stainless steel (SS) archwire each from the manufacturers American Orthodontics, OrthoTechnology, and All-Star Orthodontics. After analyzing the composition of each wire by energy-dispersive X-ray analysis, the SR of each wire was determined by scanning electron microscopy (SEM) and surface profilometry. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests (α < 0.05). Results The average SR of NiTi wires manufactured by Smart Technology, American Orthodontics, OrthoTechnology, and All-Star Orthodontics were 1,289 ± 915 A°, 1,378 ± 372 A°, 2,444 ± 369 A°, and 5,242 ± 2,832 A°, respectively. The average SR of SS wires manufactured by All-Star Orthodontics, OrthoTechnology, and American Orthodontics were 710 ± 210 A°, 1,831 ± 1,156 A°, and 4,018 ± 2,214 A°, respectively. Similar to the results of profilometry, the SEM images showed more defects and cracks on the SS wire made by American Orthodontics and the NiTi wire made by All-Star Orthodontics than others. Conclusions The NiTi wire manufactured by All-Star Orthodontics and the SS wire made by American Orthodontics were the roughest wires. PMID:23112943

Blood levels of dioxins, furans, dioxin-like PCBs, and TEQs in general populations: a review, 1989-2010.

PubMed

Consonni, Dario; Sindaco, Raffaella; Bertazzi, Pier Alberto

2012-09-01

A comprehensive worldwide literature review of blood levels of dioxins and dioxin-like compounds in non-exposed adult general populations was performed. The studies published in 1989-2010 reporting information on polychlorinated dibenzo-para-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho-PCBs (nPCBs), mono-ortho-PCBs (mPCBs) levels and Toxic Equivalencies (TEQs, a summary weighted measure of their combined toxicity) were reviewed. TEQs were calculated using as standard the most recent WHO 2005 reevaluation of Toxic Equivalency Factors (TEFs). Weighted multiple regression analyses adjusted for year, subject's age, type of sample analyzed, method used for values below detection limit, and central tendency measure used were performed for each congener and standardized TEQs (log-transformed). We identified 187 studies regarding 29,687 subjects of 26 countries. Year of blood collection ranged from 1985 to 2008. The studies reporting congener levels 161. In adjusted analyses, European countries showed higher levels of most dioxin-like congeners and TEQs. A strong positive association of subjects' age with most congeners and with TEQ values was found, confirming previous findings. Significant decreases over time (1985-2008) were documented for PCCDs, PCDFs, and TEQs including their contributions. No significant decrease was found for non-ortho-PCBs, notably PCB 126. Only some mono-ortho-PCBs showed clear significant declines. Accordingly, TEQs including only PCB contribution did not decrease over time. In interpreting these findings, it should be considered that for dioxin-like PCBs the analysis period was shorter (17 years), since these compounds were first measured in 1992. Copyright © 2012 Elsevier Ltd. All rights reserved.

Analysis of the S{sub 2}←S{sub 0} vibronic spectrum of the ortho-cyanophenol dimer using a multimode vibronic coupling approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kopec, Sabine; Köppel, Horst; Ottiger, Philipp

2015-02-28

The S{sub 2}←S{sub 0} vibronic spectrum of the ortho-cyanophenol dimer (oCP){sub 2} is analyzed in a joint experimental and theoretical investigation. Vibronic excitation energies up to 750 cm{sup −1} are covered, which extends our previous analysis of the quenching of the excitonic splitting in this and related species [Kopec et al., J. Chem. Phys. 137, 184312 (2012)]. As we demonstrate, this necessitates an extension of the coupling model. Accordingly, we compute the potential energy surfaces of the ortho-cyanophenol dimer (oCP){sub 2} along all relevant normal modes using the approximate second-order coupled cluster method RI-CC2 and extract the corresponding coupling constantsmore » using the linear and quadratic vibronic coupling scheme. These serve as the basis to calculate the vibronic spectrum. The theoretical results are found to be in good agreement with the experimental highly resolved resonant two-photon ionization spectrum. This allows to interpret key features of the excitonic and vibronic interactions in terms of nodal patterns of the underlying vibronic wave functions.« less

Construction of Escherichia coli Strains for Conversion of Nitroacetophenones to ortho-Aminophenols

DTIC Science & Technology

2003-11-01

curve for quantification by HPLC . NB, 2-nitrotoluene, 3-nitrotoluene, 4-nitrobiphenyl ether, and 1-nitronaphthalene and the aminophenols formed were...pH 8.0, containing 1% glucose. Production of aminophenol or 2AAP from the nitroacetophenone was monitored by HPLC . VOL. 69, 2003 BIOSYNTHESIS OF ortho...ortho- Aminophenols Venkateswarlu Kadiyala, Lloyd J. Nadeau, and Jim C. Spain* Air Force Research Laboratory, Tyndall Air Force Base, Florida 32403-5323

Deployment Family Stress: Child Neglect and Maltreatment in U.S. Army Families

DTIC Science & Technology

2012-10-01

for consideration of an article submission upon the completion of the analyses and written manuscript: (1) Ortho Psychiatry, (2) Child Abuse and...manuscript has been written, the following peer-reviewed journals will be considered for submission of the article: (1) Ortho Psychiatry, (2) Child Abuse and...three journals have been identified for consideration of the final manuscript submission, once it has been completed: (1) Ortho Psychiatry, (2) Child

High explosive compound

DOEpatents

Crawford, Theodore C.

1976-01-01

1. A low detonation velocity explosive consisting essentially of a particulate mixture of ortho-boric acid and trinitrotoluene, said mixture containing from about 25 percent to about 65 percent by weight of ortho-boric acid, said ortho-boric acid comprised of from 60 percent to 90 percent of spherical particles having a mean particle size of about 275 microns and 10 percent to 40 percent of spherical particles having a particle size less than about 44 microns.

Thermal Stability Characteristics of Nitroaromatic Compounds.

DTIC Science & Technology

1986-09-15

of a methyl ortho to the nitro group in nitroaromatic compounds introduces a new element into the decomposition behavior of such compounds. Inasmuch...thus without the aid of acid, base or photon catalysis. It is clear that the presence of a methyl ortho to the nitro group in nitroaromatic compounds...particular interest in terms of the substance of this work is the drastic change in reaction product when a methyl group is ortho to the nitro . Furthermore

Poly(ortho-phenylenediamine-co-aniline) based copolymer with improved capacitance

NASA Astrophysics Data System (ADS)

Olmedo-Martínez, Jorge L.; Farías-Mancilla, Bárbara I.; Vega-Rios, Alejandro; Zaragoza-Contreras, E. Armando

2017-10-01

A poly(ortho-phenylenediamine-co-aniline) copolymer is synthesized via the oxidative route, using a 1:1 M ratio of aniline to ortho-phenylenediamine (oPDA) and ammonium persulfate as the oxidizing agent. Infrared spectroscopy indicates that the copolymer contains the functional groups typically present in polyaniline and poly(ortho-phenylenediamine); whereas UV-vis-NIR spectroscopy shows that the copolymer adopts a phenazine-type structure. Cyclic voltammetry evidences the copolymer synthesis, as a redox peak at -65 mV, different from those exhibited by polyaniline (160 mV and 600 mV) or poly(o-phenylenediamine) (-240 mV) is observed. Finally, electrochemical impedance spectroscopy and the charge/discharge test provide support to propose the copolymer application in electrodes for supercapacitors.

Ortho-para spin isomers of the protons in the methylene group--possible implications for protein structure.

PubMed

Shinitzky, Meir; Elitzur, Avshalom C

2006-09-01

The two hydrogen atoms attached to the carbon in the methylene group are of two different spin configurations, similar to those in the case of water: ortho, where the two proton spins are parallel to each other, and para, where they are antiparallel. The ortho configuration has three degenerate states, while the para configuration is singular, leading to a statistical ratio of these isomers 3:1 ortho/para. Such spin isomers are present in glycine and most chiral amino acids where they may induce broadening of structural zones, a possibility which remains to be assessed. The implications of this neglected possibility could be far-reaching, in particular with respect to protein structure and the origins of biochirality.

Rotational spectra of the van der Waals complexes of molecular hydrogen and OCS.

PubMed

Yu, Zhenhong; Higgins, Kelly J; Klemperer, William; McCarthy, Michael C; Thaddeus, Patrick; Liao, Kristine; Jäger, Wolfgang

2007-08-07

The a- and b-type rotational transitions of the weakly bound complexes formed by molecular hydrogen and OCS, para-H2-OCS, ortho-H2-OCS, HD-OCS, para-D2-OCS, and ortho-D2-OCS, have been measured by Fourier transform microwave spectroscopy. All five species have ground rotational states with total rotational angular momentum J=0, regardless of whether the hydrogen rotational angular momentum is j=0 as in para-H2, ortho-D2, and HD or j=1 as in ortho-H2 and para-D2. This indicates quenching of the hydrogen angular momentum for the ortho-H2 and para-D2 species by the anisotropy of the intermolecular potential. The ground states of these complexes are slightly asymmetric prolate tops, with the hydrogen center of mass located on the side of the OCS, giving a planar T-shaped molecular geometry. The hydrogen spatial distribution is spherical in the three j=0 species, while it is bilobal and oriented nearly parallel to the OCS in the ground state of the two j=1 species. The j=1 species show strong Coriolis coupling with unobserved low-lying excited states. The abundance of para-H2-OCS relative to ortho-H2-OCS increases exponentially with decreasing normal H2 component in H2He gas mixtures, making the observation of para-H2-OCS in the presence of the more strongly bound ortho-H2-OCS dependent on using lower concentrations of H2. The determined rotational constants are A=22 401.889(4) MHz, B=5993.774(2) MHz, and C=4602.038(2) MHz for para-H2-OCS; A=22 942.218(6) MHz, B=5675.156(7) MHz, and C=4542.960(7) MHz for ortho-H2-OCS; A=15 970.010(3) MHz, B=5847.595(1) MHz, and C=4177.699(1) MHz for HD-OCS; A=12 829.2875(9) MHz, B=5671.3573(7) MHz, and C=3846.7041(6) MHz for ortho-D2-OCS; and A=13 046.800(3) MHz, B=5454.612(2) MHz, and C=3834.590(2) MHz for para-D2-OCS.

Molecular polygamy: The promiscuity of l-phenylalanyl-tRNA-synthetase triggers misincorporation of meta- and ortho-tyrosine in monoclonal antibodies expressed by Chinese hamster ovary cells.

PubMed

Popp, Oliver; Larraillet, Vincent; Kettenberger, Hubert; Gorr, Ingo H; Hilger, Maximiliane; Lipsmeier, Florian; Zeck, Anne; Beaucamp, Nicola

2015-06-01

In-depth analytical characterization of biotherapeutics originating from different production batches is mandatory to ensure product safety and consistent molecule efficacy. Previously, we have shown unintended incorporation of tyrosine (Tyr) and leucine/isoleucine (Leu/Ile) at phenylalanine (Phe) positions in a recombinant produced monoclonal antibody (mAb) using an orthogonal MASCOT/SIEVE based approach for mass spectrometry data analysis. The misincorporation could be avoided by sufficient supply of phenylalanine throughout the process. Several non-annotated signals in the primarily chromatographic peptide separation step for apparently single Phe→Tyr sequence variants (SVs) suggest a role for isobar tyrosine isoforms. Meta- and ortho-Tyr are spontaneously generated during aerobic fed-batch production processes using Chinese hamster ovary (CHO) cell lines. Process induced meta- and ortho-Tyr but not proteinogenic para-Tyr are incorporated at Phe locations in Phe-starved CHO cultures expressing a recombinant mAb. Furthermore, meta- and ortho-Tyr are preferably misincorporated over Leu. Structural modeling of the l-phenylalanyl-tRNA-synthetase (PheRS) substrate activation site indicates a possible fit of non-cognate ortho-Tyr and meta-Tyr substrates. Dose-dependent misincorporations of Tyr isoforms support the hypothesis that meta- and ortho-Tyr are competing, alternative substrates for PheRS in CHO processes. Finally, easily accessible at-line surrogate markers for Phe→Tyr SV formation in biotherapeutic production were defined by the calculation of critical ratios for meta-Tyr/Phe and ortho-Tyr/Phe to support early prediction of SV probability, and finally, to allow for immediate process controlled Phe→Tyr SV prevention. © 2014 Wiley Periodicals, Inc.

Triphenylamine based reactive coloro/fluorimetric chemosensors: Structural isomerism and solvent dependent sensitivity and selectivity

NASA Astrophysics Data System (ADS)

Kundu, Anu; Anthony, Savarimuthu Philip

2018-01-01

Triphenyl amine based chemosensors, (2-(((2-(9H-carbazol-9-yl)phenyl)imino)methyl)-5-(diphenylamino)phenol (ortho-CPDP) and 2-(((4-(9H-carbazol-9-yl)phenyl)imino)methyl)-5-(diphenylamino)phenol (para-CPDP), showed solvent and isomerism dependent selective coloro/fluorometric sensing of multiple metal ions (Fe3 +, Al3 + and Zn2 +) with distinguishable responses. In CH3CN, ortho and para-CPDP selectively produced yellow color upon addition of Al3 + and Fe3 + that was slowly disappeared. The yellow color of ortho and para-CPDP in DMF was decolourised selectively by adding Al3 + and Fe3 +. Both ortho and para-CPDP in CH3CN showed nearly similar rate of decolourization for Fe3 + and Al3 +. However, the rate of decolourization of ortho and para-CPDP in DMF was different for Fe3 + (10 μM, 8 min) and Al3 + (5 × 10- 4 M, 40 min) ions. The limit of detection of para-CPDP for Fe3 + is 10 μM and Al3 + 500 μM. The mechanistic studies revealed the imine hydrolysis of ortho and para-CPDP in presence of Lewis acidic Fe3 + and Al3 +. The reactivity based sensing lead to high selectivity for Al3 + and Fe3 + ions. Further, para-CPDP exhibited selective fluorescence turn-on for Zn2 + in DMF (λmax = 513 nm) and detection limit of 6.0 μM. Thus, reactive chemosensors, ortho and para-CPDP, exhibited selective and distinguishable colorimetric sensing of Fe3 + and Al3 + ions and isomerism and solvent dependent fluorescence sensing of Zn2 +.

Evaluation of Six Options for Obtaining Red Water

DTIC Science & Technology

1993-08-01

soluble species and extraction.I The first step, nitration, is accomplished in three successive stages whereby a nitro I (-NO2) group is attached at the 2...4, and 6 positions of the benzene ring of toluene2. Substitution of the nitro group for hydrogen results in water formation requiring higher...isomers, ortho -, meta-, and para-, are formed; but the ortho - is predominant. The ortho - and para- isomers nitrate further to o -TNT in later stages

Effectiveness of FeEDDHA, FeEDDHMA, and FeHBED in Preventing Iron-Deficiency Chlorosis in Soybean.

PubMed

Bin, Levi M; Weng, Liping; Bugter, Marcel H J

2016-11-09

The performance of FeHBED in preventing Fe deficiency chlorosis in soybean (Glycine max (L.) Merr.) in comparison to FeEDDHA and FeEDDHMA was studied, as well as the importance of the ortho-ortho and ortho-para/rest isomers in defining the performance. To this end, chlorophyll production (SPAD), plant dry matter yield, and the mass fractions of important mineral elements in the plant were quantified in a greenhouse pot experiment. All three Fe chelates increased SPAD index and dry matter yield compared to the control. The effect of FeHBED on chlorophyll production was visible over a longer time span than that of FeEDDHA and FeEDDHMA. Additionally, FeHBED did not suppress Mn uptake as much as the other Fe chelates. Compared to the other Fe chelates, total Fe content in the young leaves was lower in the FeHBED treatment; however, total Fe content was not directly related to chlorophyll production and biomass yield. For each chelate, the ortho-ortho isomer was found to be more effective than the other isomers evaluated.

Ultraefficient homogeneous catalyst for the CO2-to-CO electrochemical conversion.

PubMed

Costentin, Cyrille; Passard, Guillaume; Robert, Marc; Savéant, Jean-Michel

2014-10-21

A very efficient electrogenerated Fe(0) porphyrin catalyst was obtained by substituting in tetraphenylporphyrin two of the opposite phenyl rings by ortho-, ortho'-phenol groups while the other two are perfluorinated. It proves to be an excellent catalyst of the CO2-to-CO conversion as to selectivity (the CO faradaic yield is nearly quantitative), overpotential, and turnover frequency. Benchmarking with other catalysts, through catalytic Tafel plots, shows that it is the most efficient, to the best of our knowledge, homogeneous molecular catalyst of the CO2-to-CO conversion at present. Comparison with another Fe(0) tetraphenylporphyrin bearing eight ortho-, ortho'-phenol functionalities launches a general strategy where changes in substituents will be designed so as to optimize the operational combination of all catalyst elements of merit.

Ortho and parahydrogen in interstellar material

NASA Technical Reports Server (NTRS)

Reeves, R. R.; Harteck, P.

1979-01-01

The ortho/para molecular hydrogen ratio in the interstellar medium is considered. It is shown that the ortho/para ratio will be 3:1 in practically all chemical reactions, even at relatively low temperatures. Two examples of exothermic processes that will result in the formation of a 3:1 ortho:para ratio, corresponding to a high-temperature equilibrium, are examined: H2 formation via three-body or surface recombination and catalytic recombination involving electrons and H(-) ions. Gas-phase scrambling ion reactions are also discussed, and it is suggested that virtually all the H2 equilibrated via scrambling reactions involving H(+) and H3(+) ions should exist as parahydrogen in the J ? 0 quantum state. Arguments are given that deuterium cannot interfere with the long scrambling chain that results in parahydrogen formation.

A magnetically focused molecular beam of ortho-water.

PubMed

Kravchuk, T; Reznikov, M; Tichonov, P; Avidor, N; Meir, Y; Bekkerman, A; Alexandrowicz, G

2011-01-21

Like dihydrogen, water exists as two spin isomers, ortho and para, with the nuclear magnetic moments of the hydrogen atoms either parallel or antiparallel. The ratio of the two spin isomers and their physical properties play an important role in a wide variety of research fields, ranging from astrophysics to nuclear magnetic resonance (NMR). Unlike ortho and para H(2), however, the two water isomers remain challenging to separate, and as a consequence, very little is currently known about their different physical properties. Here, we report the formation of a magnetically focused molecular beam of ortho-water. The beam we formed also had a particular spin projection. Thus, in the presence of holding magnetic fields, the water molecules are hyperpolarized, laying the foundation for ultrasensitive NMR experiments in the future.

Strong bases. Directed ortho-meta'- and meta-meta'-dimetalations: a template base approach to deprotonation.

PubMed

Martínez-Martínez, Antonio J; Kennedy, Alan R; Mulvey, Robert E; O'Hara, Charles T

2014-11-14

The regioselectivity of deprotonation reactions between arene substrates and basic metalating agents is usually governed by the electronic and/or coordinative characteristics of a directing group attached to the benzene ring. Generally, the reaction takes place in the ortho position, adjacent to the substituent. Here, we introduce a protocol by which the metalating agent, a disodium-monomagnesium alkyl-amide, forms a template that extends regioselectivity to more distant arene sites. Depending on the nature of the directing group, ortho-meta' or meta-meta' dimetalation is observed, in the latter case breaking the dogma of ortho metalation. This concept is elaborated through the characterization of both organometallic intermediates and electrophilically quenched products. Copyright © 2014, American Association for the Advancement of Science.

Quantitation of ortho-cresyl phosphate adducts to butyrylcholinesterase in human serum by immunomagnetic-UHPLC-MS/MS.

PubMed

Johnson, Darryl; Carter, Melissa D; Crow, Brian S; Isenberg, Samantha L; Graham, Leigh Ann; Erol, H Akin; Watson, Caroline M; Pantazides, Brooke G; van der Schans, Marcel J; Langenberg, Jan P; Noort, Daan; Blake, Thomas A; Thomas, Jerry D; Johnson, Rudolph C

2015-04-01

Tri-ortho-cresyl phosphate (ToCP) is an anti-wear, flame retardant additive used in industrial lubricants, hydraulic fluids and gasoline. The neurotoxic effects of ToCP arise from the liver-activated metabolite 2-(o-cresyl)-4H-1,3,2-benzodioxaphosphoran-2-one (cresyl saligenin phosphate or CBDP), which inhibits esterase enzymes including butyrylcholinesterase (BChE). Following BChE adduction, CBDP undergoes hydrolysis to form the aged adduct ortho-cresyl phosphoserine (oCP-BChE), thus providing a biomarker of CBDP exposure. Previous studies have identified ToCP in aircraft cabin and cockpit air, but assessing human exposure has been hampered by the lack of a laboratory assay to confirm exposure. This work presents the development of an immunomagnetic-UHPLC-MS/MS method for the quantitation of unadducted BChE and the long-term CBDP biomarker, oCP-BChE, in human serum. The method has a reportable range from 2.0 ng/ml to 150 ng/ml, which is consistent with the sensitivity of methods used to detect organophosphorus nerve agent protein adducts. The assay demonstrated high intraday and interday accuracy (≥85%) and precision (RSD ≤ 15%) across the calibration range. The method was developed for future analyses of potential human exposure to CBDP. Analysis of human serum inhibited in vitro with CBDP demonstrated that the oCP-BChE adduct was stable for at least 72 h at 4, 22 and 37 °C. Compared to a previously reported assay, this method requires 75% less sample volume, reduces analysis time by a factor of 20 and demonstrates a threefold improvement in sensitivity. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Mechanistic aspects of the tyrosinase oxidation of hydroquinone.

PubMed

Ramsden, Christopher A; Riley, Patrick A

2014-06-01

Contradictory reports on the behaviour of hydroquinone as a tyrosinase substrate are reconciled in terms of the ability of the initially formed ortho-quinone to tautomerise to the thermodynamically more stable para-quinone isomer. Oxidation of phenols by native tyrosinase requires activation by in situ formation of a catechol formed via an enzyme generated ortho-quinone. In the special case of hydroquinone, catechol formation is precluded by rapid tautomerisation of the ortho-quinone precursor to catechol formation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Application of a New Ensemble Conserving Quantum Dynamics Simulation Algorithm to Liquid para-Hydrogen and ortho-Deuterium

DOE PAGES

Smith, Kyle K.G.; Poulsen, Jens Aage; Nyman, Gunnar; ...

2015-06-30

Here, we apply the Feynman-Kleinert Quasi-Classical Wigner (FK-QCW) method developed in our previous work [Smith et al., J. Chem. Phys. 142, 244112 (2015)] for the determination of the dynamic structure factor of liquid para-hydrogen and ortho-deuterium at state points of (T = 20.0 K, n = 21.24 nm -3) and (T = 23.0 K, n = 24.61 nm -3), respectively. When applied to this challenging system, it is shown that this new FK-QCW method consistently reproduces the experimental dynamic structure factor reported by Smith et al. [J. Chem. Phys. 140, 034501 (2014)] for all momentum transfers considered. Moreover, this showsmore » that FK-QCW provides a substantial improvement over the Feynman-Kleinert linearized path-integral method, in which purely classical dynamics are used. Furthermore, for small momentum transfers, it is shown that FK-QCW provides nearly the same results as ring-polymer molecular dynamics (RPMD), thus suggesting that FK-QCW provides a potentially more appealing algorithm than RPMD since it is not formally limited to correlation functions involving linear operators.« less

Application of a New Ensemble Conserving Quantum Dynamics Simulation Algorithm to Liquid para-Hydrogen and ortho-Deuterium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Kyle K.G.; Poulsen, Jens Aage; Nyman, Gunnar

Here, we apply the Feynman-Kleinert Quasi-Classical Wigner (FK-QCW) method developed in our previous work [Smith et al., J. Chem. Phys. 142, 244112 (2015)] for the determination of the dynamic structure factor of liquid para-hydrogen and ortho-deuterium at state points of (T = 20.0 K, n = 21.24 nm -3) and (T = 23.0 K, n = 24.61 nm -3), respectively. When applied to this challenging system, it is shown that this new FK-QCW method consistently reproduces the experimental dynamic structure factor reported by Smith et al. [J. Chem. Phys. 140, 034501 (2014)] for all momentum transfers considered. Moreover, this showsmore » that FK-QCW provides a substantial improvement over the Feynman-Kleinert linearized path-integral method, in which purely classical dynamics are used. Furthermore, for small momentum transfers, it is shown that FK-QCW provides nearly the same results as ring-polymer molecular dynamics (RPMD), thus suggesting that FK-QCW provides a potentially more appealing algorithm than RPMD since it is not formally limited to correlation functions involving linear operators.« less

Application of a new ensemble conserving quantum dynamics simulation algorithm to liquid para-hydrogen and ortho-deuterium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Kyle K. G., E-mail: kylesmith@utexas.edu; Poulsen, Jens Aage, E-mail: jens72@chem.gu.se; Nyman, Gunnar, E-mail: nyman@chem.gu.se

We apply the Feynman-Kleinert Quasi-Classical Wigner (FK-QCW) method developed in our previous work [Smith et al., J. Chem. Phys. 142, 244112 (2015)] for the determination of the dynamic structure factor of liquid para-hydrogen and ortho-deuterium at state points of (T = 20.0 K, n = 21.24 nm{sup −3}) and (T = 23.0 K, n = 24.61 nm{sup −3}), respectively. When applied to this challenging system, it is shown that this new FK-QCW method consistently reproduces the experimental dynamic structure factor reported by Smith et al. [J. Chem. Phys. 140, 034501 (2014)] for all momentum transfers considered. This shows that FK-QCWmore » provides a substantial improvement over the Feynman-Kleinert linearized path-integral method, in which purely classical dynamics are used. Furthermore, for small momentum transfers, it is shown that FK-QCW provides nearly the same results as ring-polymer molecular dynamics (RPMD), thus suggesting that FK-QCW provides a potentially more appealing algorithm than RPMD since it is not formally limited to correlation functions involving linear operators.« less

Application of a new ensemble conserving quantum dynamics simulation algorithm to liquid para-hydrogen and ortho-deuterium.

PubMed

Smith, Kyle K G; Poulsen, Jens Aage; Nyman, Gunnar; Cunsolo, Alessandro; Rossky, Peter J

2015-06-28

We apply the Feynman-Kleinert Quasi-Classical Wigner (FK-QCW) method developed in our previous work [Smith et al., J. Chem. Phys. 142, 244112 (2015)] for the determination of the dynamic structure factor of liquid para-hydrogen and ortho-deuterium at state points of (T = 20.0 K, n = 21.24 nm(-3)) and (T = 23.0 K, n = 24.61 nm(-3)), respectively. When applied to this challenging system, it is shown that this new FK-QCW method consistently reproduces the experimental dynamic structure factor reported by Smith et al. [J. Chem. Phys. 140, 034501 (2014)] for all momentum transfers considered. This shows that FK-QCW provides a substantial improvement over the Feynman-Kleinert linearized path-integral method, in which purely classical dynamics are used. Furthermore, for small momentum transfers, it is shown that FK-QCW provides nearly the same results as ring-polymer molecular dynamics (RPMD), thus suggesting that FK-QCW provides a potentially more appealing algorithm than RPMD since it is not formally limited to correlation functions involving linear operators.

Rotational quenching of H2CO by molecular hydrogen: cross-sections, rates and pressure broadening

NASA Astrophysics Data System (ADS)

Wiesenfeld, L.; Faure, A.

2013-07-01

We compute the rotational quenching rates of the first 81 rotational levels of ortho- and para-H2CO in collision with ortho- and para-H2, for a temperature range of 10-300 K. We make use of the quantum close-coupling and coupled-state scattering methods combined with the high accuracy potential energy surface of Troscompt et al. Rates are significantly different from the scaled rates of H2CO in collision with He; consequently, critical densities are notably lower. We compare a full close-coupling computation of pressure broadening cross-sections with experimental data and show that our results are compatible with the low-temperature measurements of Mengel & De Lucia, for a spin temperature of H2 around 50 K.

[Comparison of eight screening tests for ant-HCV antibody].

PubMed

Deguchi, Matsuo; Kagita, Masanori; Yamashita, Naoko; Nakano, Takasi; Tahara, Kazuko; Asari, Seishi; Iwatani, Yoshinori

2002-09-01

We compared eight HCV screening tests for detection of anti-HCV antibody; Ortho Quick Chaser HCV Ab (QC), Ortho HCV Ab ELISA III (ELISA), Ortho HVC Ab PA test III (PA), Lumipulse II Ortho HCV (LUMI), IMx HCV.DAINAPACKII (IMx), ARCHITECT HCV (ARCH), Immucheck.F-HCV C50 Ab (Immu), RANREAM HCV Ab Ex II (RAN). Sera from six hundred patients were examined by these eight screening tests. The positive rates of the eight screening tests were from 9.0% to 13.2%. Forty-five sera showed discrepant results between the eight screening tests, and about half of them showed weak positive reaction and/or false positive. Twenty-five of the forty-five sera were negative for ant-HCV antibody in the CHIRON RIBA III confirmatory test, and forty-four of them were negative for HCV-RNA in the PCR method. The agreement rates between the two reagents were from 95.5% to 99.2%, but were not always high between the two reagents that used similar antigen. The specificities and sensitivities evaluated by using the RIBA III confirmatory test were excellent in ELISA, LUMI, IMx, ARCH and Immu. Three BBI seroconversion panels were used to compare the positive readings in the initial stage of HCV infection by eight screening tests. ELISA and ARCH showed the earliest positive readings, and then IMx, LUMI = RAN, PA, QC and Immu in this order. These findings indicate that ELISA and ARCH were the most excellent in the sensitivity, specificity and early diagnosis of HCV infection. However, we must pay attention to the weak positive reaction in the screening tests, because there is a possibility of "false positive".

Supported transition metal catalysts for para- to ortho-hydrogen conversion

NASA Technical Reports Server (NTRS)

Brooks, Christopher J.; Wang, Wei; Eyman, Darrell P.

1994-01-01

The main goal of this study was to develop and improve on existing catalysts for the conversion of ortho- to para-hydrogen. Starting with a commercially available Air Products nickel silicate, which had a beta value of 20, we were trying to synthesize catalysts that would be an improvement to AP. This was accomplished by preparing silicates with various metals as well as different preparation methods. We also prepared supported ruthenium catalysts by various techniques using several metal precursors to improve present technology. What was also found was that the activation conditions prior to catalytic testing was highly important for both the silicates and the supported ruthenium catalysts. While not the initial focus of the research, we made some interesting observations into the adsorption of H2 on ruthenium. This helped us to get a better understanding of how ortho- to para-H2 conversion takes place, and what features in a catalyst are important to optimize activity. Reactor design was the final area in which some interesting conclusions were drawn. As discussed earlier, the reactor catalyst bed must be constructed using straight 1/8 feet OD stainless steel tubing. It was determined that the use of 1/4 feet OD tubing caused two problems. First, the radius from the center of the bed to the wall was too great for thermal equilibrium. Since the reaction of ortho- to para-H2 is exothermic, the catalyst bed center was warmer than the edges. Second, the catalyst bed was too shallow using a 1/4 feet tube. This caused reactant blow-by which was thought to decrease the measured activity when the flow rate was increased. The 1/8 feet tube corrected both of these concerns.

Direct amidation of carboxylic acids catalyzed by ortho-iodo arylboronic acids: catalyst optimization, scope, and preliminary mechanistic study supporting a peculiar halogen acceleration effect.

PubMed

Gernigon, Nicolas; Al-Zoubi, Raed M; Hall, Dennis G

2012-10-05

The importance of amides as a component of biomolecules and synthetic products motivates the development of catalytic, direct amidation methods employing free carboxylic acids and amines that circumvent the need for stoichiometric activation or coupling reagents. ortho-Iodophenylboronic acid 4a has recently been shown to catalyze direct amidation reactions at room temperature in the presence of 4A molecular sieves as dehydrating agent. Herein, the arene core of ortho-iodoarylboronic acid catalysts has been optimized with regards to the electronic effects of ring substitution. Contrary to the expectation, it was found that electron-donating substituents are preferable, in particular, an alkoxy substituent positioned para to the iodide. The optimal new catalyst, 5-methoxy-2-iodophenylboronic acid (MIBA, 4f), was demonstrated to be kinetically more active than the parent des-methoxy catalyst 4a, providing higher yields of amide products in shorter reaction times under mild conditions at ambient temperature. Catalyst 4f is recyclable and promotes the formation of amides from aliphatic carboxylic acids and amines, and from heteroaromatic carboxylic acids and other functionalized substrates containing moieties like a free phenol, indole and pyridine. Mechanistic studies demonstrated the essential role of molecular sieves in this complex amidation process. The effect of substrate stoichiometry, concentration, and measurement of the catalyst order led to a possible catalytic cycle based on the presumed formation of an acylborate intermediate. The need for an electronically enriched ortho-iodo substituent in catalyst 4f supports a recent theoretical study (Marcelli, T. Angew. Chem. Int. Ed.2010, 49, 6840-6843) with a purported role for the iodide as a hydrogen-bond acceptor in the orthoaminal transition state.

Near-resonant rotational energy transfer in HCl–H{sub 2} inelastic collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lanza, Mathieu; Lique, François, E-mail: francois.lique@univ-lehavre.fr; Kalugina, Yulia

2014-02-14

We present a new four-dimensional (4D) potential energy surface for the HCl–H{sub 2} van der Waals system. Both molecules were treated as rigid rotors. Potential energy surface was obtained from electronic structure calculations using a coupled cluster with single, double, and perturbative triple excitations method. The four atoms were described using the augmented correlation-consistent quadruple zeta basis set and bond functions were placed at mid-distance between the HCl and H{sub 2} centers of mass for a better description of the van der Waals interaction. The global minimum is characterized by the well depth of 213.38 cm{sup −1} corresponding to themore » T-shape structure with H{sub 2} molecule on the H side of the HCl molecule. The dissociation energies D{sub 0} are 34.7 cm{sup −1} and 42.3 cm{sup −1} for the complex with para- and ortho-H{sub 2}, respectively. These theoretical results obtained using our new PES are in good agreement with experimental values [D. T. Anderson, M. Schuder, and D. J. Nesbitt, Chem. Phys. 239, 253 (1998)]. Close coupling calculations of the inelastic integral rotational cross sections of HCl in collisions with para-H{sub 2} and ortho-H{sub 2} were performed at low and intermediate collisional energies. Significant differences exist between para- and ortho-H{sub 2} results. The strongest collision-induced rotational HCl transitions are the transitions with Δj = 1 for collisions with both para-H{sub 2} and ortho-H{sub 2}. Rotational relaxation of HCl in collision with para-H{sub 2} in the rotationally excited states j = 2 is dominated by near-resonant energy transfer.« less

Ortho-para-H2 conversion by hydrogen exchange: comparison of theory and experiment.

PubMed

Lique, François; Honvault, Pascal; Faure, Alexandre

2012-10-21

We report fully-quantum time-independent calculations of cross sections and rate coefficients for the collisional (de)excitation of H(2) by H. Our calculations are based on the H(3) global potential energy surface of Mielke et al. [J. Chem. Phys. 116, 4142 (2002)]. The reactive hydrogen exchange channels are taken into account. We show that the ortho-para and para-ortho conversion of H(2) are significant processes at temperatures above ~300 K and for the last process we provide the first comparison with available experimental rate coefficients between 300 and 444 K. The good agreement between theory and experiment is a new illustration of our detailed understanding of the simplest chemical reaction. The importance of the ortho-para-H(2) conversion by hydrogen exchange in astrophysics is discussed.

Molecular hydrogen in the vicinity of NGC 7538 IRS 1 and IRS 2 - Temperature and ortho-to-para ratio

NASA Technical Reports Server (NTRS)

Hoban, Susan; Reuter, Dennis C.; Mumma, Michael J.; Storrs, Alex D.

1991-01-01

Near-infrared spectroscopic observations of the active star-forming region near NGC 7538 IRS 1 and IRS 2 were made. The relative intensities of the v = 1-0 Q(1), Q(3), and Q(5) lines of molecular hydrogen are used to calculate a rotational excitation temperature. Comparison of the measured intensity of the Q(2) transition relative to the intensity of Q(1) and Q(3) permitted the retrieval of the ratio of ortho-to-para hydrogen. It is found that an ortho-to-para ratio of between 1.6 and 2.35 is needed to explain the Q-branch line intensity ratios, depending on the excitation model used. This range in ortho-to-para ratios implies a range of molecular hydrogen formation temperature of approximately 105 K to 140 K.

Accuracy of digital American Board of Orthodontics Discrepancy Index measurements.

PubMed

Dragstrem, Kristina; Galang-Boquiren, Maria Therese S; Obrez, Ales; Costa Viana, Maria Grace; Grubb, John E; Kusnoto, Budi

2015-07-01

A digital analysis that is shown to be accurate will ease the demonstration of initial case complexity. To date, no literature exists on the accuracy of the digital American Board of Orthodontics Discrepancy Index (DI) calculations when applied to pretreatment digital models. Plaster models were obtained from 45 previous patients with varying degrees of malocclusion. Total DI scores and the target disorders were computed manually with a periodontal probe on the original plaster casts (gold standard) and digitally using Ortho Insight 3D (Motion View Software, Hixson, Tenn) and OrthoCAD (Cadent, Carlstadt, NJ). Intrarater and interrater reliabilities were assessed for 15 subjects using the Spearman rho correlation test. Accuracies of the DI scores and target disorders were assessed for all 45 subjects using Wilcoxon signed ranks tests. Intrarater and interrater reliabilities were high for total DI scores and most target disorders (r > 0.8). No significant difference was found between total DI score when measured with OrthoCAD compared with manual calculations. The total DI scores calculated by Ortho Insight 3D were found to be significantly greater than those by manual calculation by 2.71 points. The findings indicate that a DI calculated by Ortho Insight 3D may lead the clinician to overestimate case complexity. OrthoCAD's DI module was demonstrated to be a clinically acceptable alternative to manual calculation of the total scores. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Infrared Space Observatory Observations of Molecular Hydrogen in HH 54: Measurement of a Nonequilibrium Ratio of Ortho- to Para-H2

NASA Technical Reports Server (NTRS)

Neufeld, David A.; Melnick, Gary J.; Harwit, Martin

1998-01-01

We have detected the S(1), S(2), S(3), S(4), and S(5) pure rotational lines of molecular hydrogen toward the outflow source HH 54 using the Short Wavelength Spectrometer on board the Infrared Space Observatory. The observed H2 line ratios indicate the presence of warm molecular gas with an H2 density of at least 10(sup 5) /cc and a temperature approximately 650 K in which the ratio of ortho- to para-H2 is only 1.2 -+ 0.4, significantly smaller than the equilibrium ratio of 3 expected in gas at that temperature. These observations imply that the measured ratio of ortho- to para-H2 is the legacy of an earlier stage in the thermal history of the gas when the gas had reached equilibrium at a temperature approximately 90 K. Based upon the expected timescale for equilibration, we argue that the nonequilibrium ratio of ortho- to para-H2 observed in HH 54 serves as a chronometer that places a conservative upper limit of approximately 5000 yr on the period for which the emitting gas has been warm. The S(2)/,S(l) and S(3)/S(1) H2 line ratios measured toward HH 54 are consistent with recent theoretical models of Timmermann for the conversion of para- to ortho-H2 behind slow, C-type shocks, but only if the preshock ratio of ortho- to para-H2 was approximately < 0.2.

Potential Metabolic Activation of a Representative C2-Alkylated Polycyclic Aromatic Hydrocarbon 6-Ethylchrysene Associated with the Deepwater Horizon Oil Spill in Human Hepatoma (HepG2) Cells

PubMed Central

2016-01-01

Exposure to polycyclic aromatic hydrocarbons (PAHs) is the major human health hazard associated with the Deepwater Horizon oil spill. C2-Chrysenes are representative PAHs present in crude oil and could contaminate the food chain. We describe the metabolism of a C2-chrysene regioisomer, 6-ethylchrysene (6-EC), in human HepG2 cells. The structures of the metabolites were identified by HPLC-UV-fluorescence detection and LC-MS/MS. 6-EC-tetraol isomers were identified as signature metabolites of the diol-epoxide pathway. O-Monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and N-acetyl-l-cysteine(NAC)-6-EC-ortho-quinone were discovered as signature metabolites of the ortho-quinone pathway. Potential dual metabolic activation of 6-EC involving the formation of bis-electrophiles, i.e., a mono-diol-epoxide and a mono-ortho-quinone within the same structure, bis-diol-epoxides, and bis-ortho-quinones was observed as well. The identification of 6-EC-tetraol, O-monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and NAC-6-EC-ortho-quinone supports potential metabolic activation of 6-EC by P450 and AKR enzymes followed by metabolic detoxification of the ortho-quinone through interception of its redox cycling capability by catechol-O-methyltransferase and sulfotransferase enzymes. The tetraols and catechol conjugates could be used as biomarkers of human exposure to 6-EC resulting from oil spills. PMID:27054409

THERMAL PROPERTIES OF SOLID HYDROGEN UNDER PRESSURE (thesis)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orttung, W.H.

1961-02-01

A calorimeter was designed and constructed for use in the temperature interval 1 to 25 deg K with samples of solid hydrogen under pressures up to 12,000 kg/cm/sup 2/. Unusual features of the calorimeter include the use of two baths for liquid hydrogen or helium, a jaw-type thermal contact capable of high contact pressure, and a set of flanges at the cell level for ready access. The associated high-pressuregenerating apparatus was also designed and constructed. Pressures were generated with oil pumps and an intensifier. The oil was separated from the hydrogen by steel U-tubes half full of mercury, three ofmore » which were required for different pressure ranges. The highest-pressure U-tube was isolated from the rest of the system by mercury frozen in a steel capillary. The hydrogen entered the calorimeter through high-pressure capillary tubing, in which it was then frozen to isolate the sample in the cell. Catalyst chambers were constructed for the conversion of normal hydrogen to para hydrogen, and a three- stage system uti lizing alumina catalyst at liquid-hydrogen temperature was constructed for the separation of ortho hydrogen from para hydrogen. Because the calorimeter was of unconventional design, various modifications and procedures had to bo worked out. A dummy cell was used for these developments. The high- pressure apparatas was tested to 6000 kg/cm/sup 2/ with hydrogen at room temperature. Satisfactory highpressure seals for the low-temperatare cell were not developed soon enough to enable data to be taken. The theory of the anomalous heat capacity for low concentrations of ortho hydrogen or para deuterium Was extended by a calculation based on the angular potential energy between adjacent molecules. At 1 atm it was found that only electrostatic quadrupole-quadrupole interactions had to be considered, but at higher pressures, the valence forces became important. The case of three ortho molecules in a row was also treated in the quadrupole approximation. The heat capacity predicted by this model is somewhat different from that predicted for isolated ortho-ortho pairs. The theory was compared with the avnilable 1-atm data, taking into consideration the relation between the total ortho concentration and the relative amounts of isolated ortho molecules, isolated pairs of ortho molecules, and more complicated configurations. The suggestion of T. Nakamura that an additional term in the anomalous heat capacity proportional to the ortho concentration is needed to explain the data seems to be supported by the analysis, although comparison with a larger amount of data would be desirable. (auth)« less

Probes for Narcotic Receptor Mediated Phenomena. 37.1 Synthesis and Opioid Binding Affinity of the Final Pair of Oxide-Bridged Phenylmorphans, the ortho- and para-b Isomers and Their N-Phenethyl Analogues, and the Synthesis of the N-Phenethyl Analogues of the ortho- and para-d Isomers

PubMed Central

Kurimura, Muneaki; Liu, Hehua; Sulima, Agnieszka; Hashimoto, Akihiro; Przybyl, Anna K.; Ohshima, Etsuo; Kodato, Shinichi; Deschamps, Jeffrey R.; Dersch, Christina M.; Rothman, Richard B.; Lee, Yong Sok; Jacobson, Arthur E.; Rice, Kenner C.

2008-01-01

In the isomeric series of 12 racemic topologically rigid N-methyl analogues of oxide-bridged phenylmorphans, all but two of the racemates, the ortho- and para-b-oxide-bridged phenylmorphansa 20 and 12, have remained to be synthesized. The b-isomers were very difficult to synthesize because of the highly strained 5,6-trans-fused ring junction that had to be formed. Our successful strategy required functionalization of the position para (or ortho) to a fluorine atom on the aromatic ring using an electron-withdrawing nitro group to activate that fluorine. The racemic N-phenethyl analogues 24 and 16 were moderately potent κ-receptor antagonists in the [35S]GTPγS assay. We synthesized the N-phenethyl-substituted oxide-bridged phenylmorphans in the ortho- and para-d oxide-bridged phenylmorphana series (51 and 52) which had not been previously evaluated using contemporary receptor binding assays to see whether they also have higher affinity for opioid receptors than their N-methyl relatives 46 and 47. PMID:19053757

Subsurface transport of orthophosphate in five agricultural watersheds, USA

USGS Publications Warehouse

Domagalski, Joseph L.; Johnson, Henry M.

2011-01-01

Concentrations of dissolved orthophosphate (ortho P) in the unsaturated zone, groundwater, tile drains, and groundwater/stream water interfaces were assessed in five agricultural watersheds to determine the potential for subsurface transport. Concentrations of iron oxides were measured in the aquifer material and adsorption of ortho P on oxide surfaces was assessed by geochemical modeling. Attenuation of ortho P in these aquifers was attributed primarily to sorption onto iron oxides, and in one location onto clay minerals. Only one location showed a clear indication of phosphorus transport to a stream from groundwater discharge, although groundwater did contribute to the stream load elsewhere. Subsurface ortho P movement at a site in California resulted in a plume down gradient from orchards, which was attenuated by a 200 m thick riparian zone with natural vegetation. Iron oxides had an effect on phosphorus movement and concentrations at all locations, and groundwater chemistry, especially pH, exerted a major control on the amount of phosphorus adsorbed. Groundwater pH at a site in Maryland was below 5 and that resulted in complete sequestration of phosphorus and no movement toward the stream. Geochemical modeling indicated that as the surfaces approached saturation, groundwater concentrations of ortho P rise rapidly.

The use of the DR CALUX bioassay and indicator polychlorinated biphenyls for screening of elevated levels of dioxins and dioxin-like polychlorinated biphenyls in eel.

PubMed

Hoogenboom, Ron; Bovee, Toine; Traag, Win; Hoogerbrugge, Ronald; Baumann, Bert; Portier, Liza; van de Weg, Guido; de Vries, Jaap

2006-10-01

The DR CALUX bioassay is a very suitable screening method for dioxins and dioxin-like-PCBs in feed and food. This was, e. g. demonstrated in a survey in the Netherlands to control the dioxin levels in eel. The DR CALUX assay, but also indicator polychlorinated biphenyls (PCB) were evaluated as a screening method. Based on the limit for polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/F) [at that time 8 pg toxic equivalents (TEQ)/g eel], and the relation between PCDD/F and dioxin-like-PCB, a decision limit of 30 pg TEQ/g eel was used for screening of 153 field samples. Suspected samples (21) and part of the higher contaminated negative samples (35) were analyzed by GC/MS for dioxins, non-ortho, mono-ortho and indicator PCB, revealing 13 samples exceeding the action limit of 30 pg TEQ/g eel. Only one sample slightly exceeded the dioxin level of 8 pg TEQ/g eel. The relatively low sensitivity for mono-ortho PCB was overcome by the use of reference samples, as shown by the correlation of 0.93 between GC/MS and CALUX determined total TEQ levels. The present data show that the DR CALUX assay can be used for screening of total TEQ levels in eel. The use for dioxins only requires a safe, and therefore relatively low, decision limit. The indicator PCB also showed a good correlation with total TEQ levels, mainly due to the large contribution of the mono-ortho PCB at higher concentrations. The relation with dioxins was very poor and as such indicator PCB seem less suitable than the DR CALUX assay for screening for dioxins only. The present study clearly shows that part of the wild eel samples contains high total TEQ levels and will exceed the future European Union limit of 12 pg TEQ/g eel for dioxins and dioxin-like PCB. Especially at high TEQ levels, dioxin-like PCB contribute most to the total TEQ. In practice, wild eel presents only a minor part of the eel consumed.

Erythrocyte Alloimmunization and Autoimmunization among Blood Donors and Recipients visiting a Tertiary Care Hospital

PubMed Central

Bains, Lovenish; Kandwal, Manoj; Parmar, Indu

2017-01-01

Introduction The ultimate aim of pretransfusion testing is the acceptable survival of donor red cells in recipient’s body and antibody detection plays a critical role in achieving the same. The cornerstone of antibody detection method is detecting an unexpected antibody as against the expected antibodies of ABO blood group system. Autoantibodies can also interfere with the detection of clinically significant alloantibodies. Aim To study the frequency of alloantibodies and autoantibodies in the healthy blood donors and patient population visiting our hospital. Materials and Methods The Column Agglutination Technology (CAT) was used for ABO RhD blood grouping, Direct Antiglobulin Test (DAT), Autocontrol (AC), Indirect Antiglobulin Test (IAT) and red cell antibody screening and the unexpected reactions in any of these tests were recorded for further evaluation. Ethylene Diamine Tetra Acetic Acid (EDTA) blood samples were used for all these tests for both blood donors and admitted patients. The CAT was exercised for the blood grouping (using ABD-Reverse Diluent cassettes) and antibody screening (using 0.8% Surgiscreen, Ortho Clinical Diagnostics Limited, USA and Low Ionic Strength Saline Ortho BLISS with AHG cassettes) on the automated immunohaematology platform ORTHO AutoVue® Innova system (Ortho Clinical Diagnostics Limited, USA). Results Among all blood donors (n=6350), seven (0.11%) donors had showed unexpected reaction. Of these, four had positive antibody screen (three having naturally occuring antibodies 2=anti-M, 1=anti-Lea and 1=inconclusive) and the other three had positive DAT. Of all the patient samples (n=6136) screened for irregular red cell antibodies, four (0.06%) patients were found to have unexpected reaction revealing one (0.02%) with anti-M antibody and the other three (0.05%) had autoantibodies in their serum. Conclusion The combined prevalence for both blood donor and recipient population (n=12,486) was found to be 0.11% at our center. The alloimmunisation among patient population was found to be lower than many other studies worldwide as our hospital does not cater to multitransfused or transfusion dependant patients with haematological disorders and majorly elective surgery patients with no history of previous blood transfusions visit our hospital. PMID:28511387

Selective and Efficient Generation of ortho-Brominated para-Substituted Phenols in ACS-Grade Methanol.

PubMed

Georgiev, David; Saes, Bartholomeus W H; Johnston, Heather J; Boys, Sarah K; Healy, Alan; Hulme, Alison N

2016-01-13

The mono ortho-bromination of phenolic building blocks by NBS has been achieved in short reaction times (15-20 min) using ACS-grade methanol as a solvent. The reactions can be conducted on phenol, naphthol and biphenol substrates, giving yields of >86% on gram scale. Excellent selectivity for the desired mono ortho-brominated products is achieved in the presence of 10 mol % para-TsOH, and the reaction is shown to be tolerant of a range of substituents, including CH3, F, and NHBoc.

pH-triggered chitosan nanogels via an ortho ester-based linkage for efficient chemotherapy.

PubMed

Yang, Guanqing; Wang, Xin; Fu, Shengxiang; Tang, Rupei; Wang, Jun

2017-09-15

We report on new types of chitosan-based nanogels via an ortho ester-based linkage, used as drug carriers for efficient chemotherapy. First, we synthesized a novel diacrylamide containing ortho ester (OEAM) as an acid-labile cross-linker. Subsequently, methacrylated succinyl-chitosan (MASCS) was prepared and polymerized with OEAM at different molar ratios to give a series of pH-triggered MASCS nanogels. Doxorubicin (DOX) as a model anticancer drug was loaded into MASCS nanogels with a loading content of 16.5%. As expected, with the incorporation of ortho ester linkages, these nanogels showed pH-triggered degradation and drug release at acidic pH values. In vitro cellular uptake shows that the DOX-loaded nanogels could be preferentially internalized by two-dimensional (2D) cells and three-dimensional (3D) multicellular spheroids (MCs), resulting in higher inhibition of the proliferation of tumor cells. In vivo biodistribution and anti-tumor effect were determined in H22 tumor-bearing mice, and the results demonstrate that the acid-labile MASCS nanogels can significantly prolong the blood circulation time of DOX and improve the accumulation in tumor areas, leading to higher therapeutic efficacy. We designed new pH-triggered chitosan nanogels via an ortho ester-based cross-linker for efficient drug-loading and chemotherapy. These drug-loaded nanogels exhibit excellent pH-triggered drug release behavior due to the degradation of ortho ester linkages in mildly acidic environments. In vitro and in vivo results demonstrate that the nanogels could be efficiently internalized by 2D cells and 3D-MCs, improve drug concentration in solid tumors, and lead to higher therapeutic efficacy. To the best of our knowledge, this is the first report on using an ortho ester-based cross-linker to prepare pH-triggered chitosan nanogels as tumor carriers, which may provide a potential route for improved safety and to increase the therapeutic efficacy of anticancer therapy. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Hazardous Waste Cleanup: Ortho-Clinical Diagnostics, Raritan, New Jersey

EPA Pesticide Factsheets

Ortho-Clinical Diagnostics (OCD) is an administration and manufacturing facility located at 1001 U.S. Route 202 North in Raritan Borough, Somerset County, New Jersey. The facility manufactures hospital and laboratory reagents used primarily for blood

ortho-Anisidine

Integrated Risk Information System (IRIS)

ortho - Anisidine ; CASRN 90 - 04 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

Asymmetric Oxidation of o-Alkylphenols with Chiral 2-(o-Iodoxyphenyl)-Oxazolines

PubMed Central

Boppisetti, Jagadish K.; Birman, Vladimir B.

2009-01-01

A new class of chiral iodine (V) derivatives has been prepared. These compounds have been found to transform ortho-alkylphenols into ortho-quinol Diels-Alder dimers with significant levels of asymmetric induction. PMID:19231848

Levels and congener pattern of polychlorinated biphenyls in the blubber of the Mediterranean bottlenose dolphins Tursiops truncatus.

PubMed

Storelli, M M; Marcotrigiano, G O

2003-01-01

Isomer specific concentrations of individual polychlorinated biphenyls (PCBs) including toxic non-ortho (IUPAC 77, 126, 169) and mono-ortho (105, 118, 156) coplanar congeners were determined in the blubber of nine bottlenose dolphins (Tursiops truncatus) stranded along the Eastern Italian coast. The total PCB concentrations ranged from 3534 to 24375 ng/g wet wt. The PCB profile was dominated by congeners 138 and 153 collectively accounting for 55% of the total PCB concentrations. Among the most toxic congeners the order of abundance was 126>169>77. The mean total 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalent of six coplanar PCBs in the blubber of bottlenose dolphins was 45596 pg/g. Non-ortho congeners contributed greater to the 2,3,7,8-TCDD toxic equivalents than mono-ortho members. Particularly, PCB 126 was the major contributor to the estimated toxic potency of PCBs in dolphins.

OrthoMaM v8: a database of orthologous exons and coding sequences for comparative genomics in mammals.

PubMed

Douzery, Emmanuel J P; Scornavacca, Celine; Romiguier, Jonathan; Belkhir, Khalid; Galtier, Nicolas; Delsuc, Frédéric; Ranwez, Vincent

2014-07-01

Comparative genomic studies extensively rely on alignments of orthologous sequences. Yet, selecting, gathering, and aligning orthologous exons and protein-coding sequences (CDS) that are relevant for a given evolutionary analysis can be a difficult and time-consuming task. In this context, we developed OrthoMaM, a database of ORTHOlogous MAmmalian Markers describing the evolutionary dynamics of orthologous genes in mammalian genomes using a phylogenetic framework. Since its first release in 2007, OrthoMaM has regularly evolved, not only to include newly available genomes but also to incorporate up-to-date software in its analytic pipeline. This eighth release integrates the 40 complete mammalian genomes available in Ensembl v73 and provides alignments, phylogenies, evolutionary descriptor information, and functional annotations for 13,404 single-copy orthologous CDS and 6,953 long exons. The graphical interface allows to easily explore OrthoMaM to identify markers with specific characteristics (e.g., taxa availability, alignment size, %G+C, evolutionary rate, chromosome location). It hence provides an efficient solution to sample preprocessed markers adapted to user-specific needs. OrthoMaM has proven to be a valuable resource for researchers interested in mammalian phylogenomics, evolutionary genomics, and has served as a source of benchmark empirical data sets in several methodological studies. OrthoMaM is available for browsing, query and complete or filtered downloads at http://www.orthomam.univ-montp2.fr/. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Phenolic Polymer Solvation in Water and Ethylene Glycol, I: Molecular Dynamics Simulations

NASA Technical Reports Server (NTRS)

Bucholz, Eric W.; Haskins, Justin B.; Monk, Joshua D.; Bauschlicher, Charles W.; Lawson, John W.

2017-01-01

Interactions between pre-cured phenolic polymer chains and a solvent have a significant impact on the structure and properties of the final post-cured phenolic resin. Developing an understanding of the nature of these interactions is important and will aid in the selection of the proper solvent that will lead to the desired final product. Here, we investigate the role of phenolic chain structure and solvent type on the overall solvation performance of the system through molecular dynamics simulations. Two types of solvents are considered, ethylene glycol (EGL) and H2O. In addition, three phenolic chain structures were considered including two novolac-type chains with either an ortho-ortho (OON) or ortho-para (OPN) backbone network and a resole-type (RES) chain with an ortho-ortho network. Each system is characterized through structural analysis of the solvation shell and hydrogen bonding environment as well as through quantification of the solvation free energy along with partitioned interaction energies between specific molecular species. The combination of the simulations and analyses indicate that EGL provides a larger solvation free energy than H2O due to more energetically favorable hydrophilic interactions as well as favorable hydrophobic interactions between CH element groups. In addition, phenolic chain structure significantly impacts solvation performance with OON having limited intermolecular hydrogen bond formations while OPN and RES interact more favorably with the solvent molecules. The results suggest that a resole-type phenolic chain with an ortho-para network should have the best solvation performance in EGL, H2O, and other similar solvents.

Infrared Space Observatory Observations of Molecular Hydrogen in HH 54: Measurement of a Nonequilibrium Ratio of Ortho- to Para-H2

NASA Technical Reports Server (NTRS)

Neufeld, David A.; Melnick, Gary J.; Harwit, Martin

1998-01-01

We have detected the S(1), S(2), S(3), S(4), and S(5) pure rotational lines of molecular hydrogen toward the outflow source HH 54 using the Short Wavelength Spectrometer on board the Infrared Space Observatory. The observed H2 line ratios indicate the presence of warm molecular gas with an H2 density of at least 10(exp 5) cm(exp -3) and a temperature approximately 650 K in which the ratio of ortho- to para-H2 is only 1.2 +/- 0.4, significantly smaller than the equilibrium ratio of 3 expected in gas at that temperature. These observations imply that the measured ratio of ortho- to para-H2 is the legacy of an earlier stage in the thermal history of the gas when the gas had reached equilibrium at a temperature approximately less than 90 K. Based upon the expected timescale for equilibration, we argue that the nonequilibrium ratio of ortho- to para-H2 observed in HH 54 serves as a chronometer that places a conservative upper limit of approximately 5000 yr on the period for which the emitting gas has been warm. The S(2)/S(1) and S(3)/S(1) H2 line ratios measured toward HH 54 are consistent with recent theoretical models of Timmermann for the conversion of para- to ortho-H2 behind slow, C-type shocks, but only if the preshock ratio of ortho- to para-H2 was approximately less than 0.2.

Phenolic Polymer Solvation in Water and Ethylene Glycol, I: Molecular Dynamics Simulations.

PubMed

Bucholz, Eric W; Haskins, Justin B; Monk, Joshua D; Bauschlicher, Charles W; Lawson, John W

2017-04-06

Interactions between pre-cured phenolic polymer chains and a solvent have a significant impact on the structure and properties of the final postcured phenolic resin. Developing an understanding of the nature of these interactions is important and will aid in the selection of the proper solvent that will lead to the desired final product. Here, we investigate the role of the phenolic chain structure and the solvent type on the overall solvation performance of the system through molecular dynamics simulations. Two types of solvents are considered: ethylene glycol (EGL) and H 2 O. In addition, three phenolic chain structures are considered, including two novolac-type chains with either an ortho-ortho (OON) or an ortho-para (OPN) backbone network and a resole-type (RES) chain with an ortho-ortho network. Each system is characterized through a structural analysis of the solvation shell and the hydrogen-bonding environment as well as through a quantification of the solvation free energy along with partitioned interaction energies between specific molecular species. The combination of simulations and the analyses indicate that EGL provides a higher solvation free energy than H 2 O due to more energetically favorable hydrophilic interactions as well as favorable hydrophobic interactions between CH element groups. In addition, the phenolic chain structure significantly affects the solvation performance, with OON having limited intermolecular hydrogen-bond formations, while OPN and RES interact more favorably with the solvent molecules. The results suggest that a resole-type phenolic chain with an ortho-para network should have the best solvation performance in EGL, H 2 O, and other similar solvents.

Benzimidazoles and benzoxazoles via the nucleophilic addition of anilines to nitroalkanes.

PubMed

Aksenov, Alexander V; Smirnov, Alexander N; Aksenov, Nicolai A; Bijieva, Asiyat S; Aksenova, Inna V; Rubin, Michael

2015-04-14

PPA-induced umpolung triggers efficient nucleophilic addition of unactivated anilines to nitroalkanes to produce N-hydroxyimidamides. The latter undergo sequential acid-promoted cyclocondensation with ortho-OH or ortho-NHR moieties to afford benzoxazoles and benzimidazoles, respectively.

MARVEL analysis of the measured high-resolution rovibrational spectra of C2H2

NASA Astrophysics Data System (ADS)

Chubb, Katy L.; Joseph, Megan; Franklin, Jack; Choudhury, Naail; Furtenbacher, Tibor; Császár, Attila G.; Gaspard, Glenda; Oguoko, Patari; Kelly, Adam; Yurchenko, Sergei N.; Tennyson, Jonathan; Sousa-Silva, Clara

2018-01-01

Rotation-vibration energy levels are determined for the electronic ground state of the acetylene molecule, 12C2H2, using the Measured Active Rotational-Vibrational Energy Levels (MARVEL) technique. 37,813 measured transitions from 61 publications are considered. The distinct components of the spectroscopic network linking ortho and para states of the molecule are considered separately. The 20,717 ortho and 17,096 para transitions measured experimentally are used to determine 6013 ortho and 5200 para energy levels. The MARVEL results are compared with alternative compilations based on the use of effective Hamiltonians.

Comment on "A centroid molecular dynamics study of liquid para hydrogen and ortho deuterium" [J. Chem. Phys. 121, 6412 (2004)].

PubMed

Miller, Thomas F; Manolopoulos, David E; Madden, Paul A; Konieczny, Martin; Oberhofer, Harald

2005-02-01

We show that the two phase points considered in the recent simulations of liquid para hydrogen by Hone and Voth lie in the liquid-vapor coexistence region of a purely classical molecular dynamics simulation. By contrast, their phase point for ortho deuterium was in the one-phase liquid region for both classical and quantum simulations. These observations are used to account for their report that quantum mechanical effects enhance the diffusion in liquid para hydrogen and decrease it in ortho deuterium.(c) 2005 American Institute of Physics.

A comparative study between para-aminophenyl and ortho-aminophenyl benzothiazoles using NMR and DFT calculations.

PubMed

Pierens, G K; Venkatachalam, T K; Reutens, D

2014-08-01

Ortho-substituted and para-substituted aminophenyl benzothiazoles were synthesised and characterised using NMR spectroscopy. A comparison of the proton chemical shift values reveals significant differences in the observed chemical shift values for the NH protons indicating the presence of a hydrogen bond in all ortho-substituted compounds as compared to the para compounds. The presence of intramolecular hydrogen bond in the ortho amino substituted aminophenyl benzothiazole forces the molecule to be planar which may be an additional advantage in developing these compounds as Alzheimer's imaging agent because the binding to amyloid fibrils prefers planar compounds. The splitting pattern of the methylene proton next to the amino group also showed significant coupling to the amino proton consistent with the notion of the existence of slow exchange and hydrogen bond in the ortho-substituted compounds. This is further verified by density functional theory calculations which yielded a near planar low energy conformer for all the o-aminophenyl benzothiazoles and displayed a hydrogen bond from the amine proton to the nitrogen of the thiazole ring. A detailed analysis of the (1)H, (13)C and (15)N NMR chemical shifts and density functional theory calculated structures of the compounds are described. Copyright © 2014 John Wiley & Sons, Ltd.

Experimental verification of the cluster model of CH3F-(ortho-H2)n in solid para-H2 by using mid-infrared pump-probe laser spectroscopy

NASA Astrophysics Data System (ADS)

Miyamoto, Yuki; Mizoguchi, Asao; Kanamori, Hideto

2017-03-01

The bleaching process in the C-F stretching mode (ν3 band) of CH3F-(ortho-H2)n [n = 0 and 1] clusters in solid para-H2 was monitored using pump and probe laser spectroscopy on the C-H stretching mode (ν1 and 2ν5 bands). From an analysis of the depleted spectral profiles, the transition frequency and linewidth of each cluster were directly determined. The results agree with the values previously derived from a deconvolution analysis of the broadened ν1/2ν5 spectrum observed by FTIR spectroscopy. The complementary increase and decrease between the n = 0 and 1 components were also verified through monitoring the ν1 and 2ν5 bands, which suggests a closed system among the CH3F-(ortho-H2)n clusters. These observations provide experimental verification of the CH3F-(ortho-H2)n cluster model. On the other hand, a trial to observe the bleaching process by pumping the C-H stretching mode was not successful. This result may be important for understanding the dynamics of vibrational relaxation processes in CH3F-(ortho-H2)n in solid para-H2.

The effect of spatial orientation on detecting motion trajectories in noise.

PubMed

Pavan, Andrea; Casco, Clara; Mather, George; Bellacosa, Rosilari M; Cuturi, Luigi F; Campana, Gianluca

2011-09-15

A series of experiments investigated the extent to which the spatial orientation of a signal line affects discrimination of its trajectory from the random trajectories of background noise lines. The orientation of the signal line was either parallel (iso-) or orthogonal (ortho-) to its motion direction and it was identical in all respects to the noise (orientation, length and speed) except for its motion direction, rendering the signal line indistinguishable from the noise on a frame-to-frame basis. We found that discrimination of ortho-trajectories was generally better than iso-trajectories. Discrimination of ortho-trajectories was largely immune to the effects of spatial jitter in the trajectory, and to variations in step size and line-length. Discrimination of iso-trajectories was reliable provided that step-size was not too short and did not exceed line length, and that the trajectory was straight. The new result that trajectory discrimination in moving line elements is modulated by line orientation suggests that ortho- and iso-trajectory discrimination rely upon two distinct mechanisms: iso-motion discrimination involves a 'motion-streak' process that combines motion information with information about orientation parallel to the motion trajectory, while ortho-motion discrimination involves extended trajectory facilitation in a network of receptive fields with orthogonal orientation tuning. Copyright © 2011 Elsevier Ltd. All rights reserved.

Experimental verification of the cluster model of CH3F-(ortho-H2)n in solid para-H2 by using mid-infrared pump-probe laser spectroscopy.

PubMed

Miyamoto, Yuki; Mizoguchi, Asao; Kanamori, Hideto

2017-03-21

The bleaching process in the C-F stretching mode (ν 3 band) of CH 3 F-(ortho-H 2 ) n [n = 0 and 1] clusters in solid para-H 2 was monitored using pump and probe laser spectroscopy on the C-H stretching mode (ν 1 and 2ν 5 bands). From an analysis of the depleted spectral profiles, the transition frequency and linewidth of each cluster were directly determined. The results agree with the values previously derived from a deconvolution analysis of the broadened ν 1 /2ν 5 spectrum observed by FTIR spectroscopy. The complementary increase and decrease between the n = 0 and 1 components were also verified through monitoring the ν 1 and 2ν 5 bands, which suggests a closed system among the CH 3 F-(ortho-H 2 ) n clusters. These observations provide experimental verification of the CH 3 F-(ortho-H 2 ) n cluster model. On the other hand, a trial to observe the bleaching process by pumping the C-H stretching mode was not successful. This result may be important for understanding the dynamics of vibrational relaxation processes in CH 3 F-(ortho-H 2 ) n in solid para-H 2 .

Metallographic structure and hardness of titanium orthodontic brackets.

PubMed

Zinelis, Spiros; Annousaki, Olga; Eliades, Theodore; Makou, Margarita

2003-11-01

To determine the elemental composition, microstructure, and hardness of two different brands of titanium (Ti) orthodontic brackets. Four specimens of each brand were embedded in epoxy resin and, after metallographic grinding and polishing, were studied under a metallographic microscope. The bonding base morphology of each bracket was studied in as-received brackets by scanning electron microscopy. Energy dispersive x-ray microanalysis (EDS) was used on polished specimens to assess the elemental composition of base and wing bracket components, and the brackets were subjected to metallographic etching to reveal the metallurgical structure. The same specimen surfaces were used for assessment of the Vickers hardness. The results were statistically analyzed by two-way analysis of variance (ANOVA) with the bracket brand and bracket region (base, wing) serving as discriminating variables, whilst further group differences were investigated with Tukey's multiple comparison test at the alpha = 0.05 level of significance. Metallographic imaging revealed that the Orthos2 brackets (Ormco, Glendora, CA, USA) consist of two parts joined together by laser welding, with large gaps along the base wing interface, whereas Rematitan brackets (Dentaurum, Ispringen, Germany) are single-piece appliances. Ti was the only element identified in Rematitan and Orthos2 base materials, while aluminium (Al) and vanadium (V) were also found in the Orthos2 wing component. Metallographic analysis showed the presence of a + b phase for Orthos2 and plate-like grains for Rematitan. The results of the Vickers hardness testing were: Orthos2 (wing): 371 +/- 22, Rematitan (wing): 272 +/- 4, Rematitan (base): 271 +/- 16, Orthos2 (base): 165 +/- 2. The findings of the present study suggest that there are significant differences in composition, microstructure and hardness between the two commercial types of Ti brackets tested; the clinical implications of the findings are discussed.

Thermal dechlorination of PCB-209 over Ca species-doped Fe₂O₃.

PubMed

Su, Guijin; Huang, Linyan; Shi, Ruifang; Liu, Yexuan; Lu, Huijie; Zhao, Yuyang; Yang, Fan; Gao, Lirong; Zheng, Minghui

2016-02-01

Degradation reaction of decachlorobiphenyl (PCB-209) was investigated over the synthesized Ca species-doped Fe2O3 at 300 °C. The 1%Ca-Fe2O3 exhibited the highest activity among the four catalysts prepared with the pseudo-first order reaction at k(obs) = 0.103 min(-1). PCB-207, PCB-197, PCB-176, PCB-184, PCB-150, PCB-136, PCB-148, PCB-104, PCB-96, PCB-54, PCB-19, PCB-4 and PCB-1 were identified as the dominant isomers in their respective nonachlorobiphenyl (NonaCB) to monochlorobiphenyl (MonoCB) homologue groups. Analysis of the hydrodechlorination products indicated that dechlorination was much more favored on meta- and para-than on ortho-positions. The formation of significantly predominant NonaCB and octachlorobiphenyl (OctaCB) isomers was attributed to lower energy principles and to the 90° dihedral angles of two aromatic rings which prevented the hydrodechlorination at ortho-positions. When the number of chlorine atoms is not more than 7, the steric effect supports the formation of predominant PCB isomers having chlorines at four ortho-positions. During the dechlorination of tetrachlorobiphenyl (TetraCB) formed to generate monochlorobiphenyl (MonoCB) isomers, the chlorine atoms fully substituted at the ortho-positions have to be successively removed, with the first two dechlorinations preferentially occurring at the two different benzene rings. This is dissimilar to that of octachloronaphthalene (PCN-75) in which the hydrodechlorination reaction happened preferentially at ortho-position due to the existence of steric effects. The opposite roles of the steric effect in ortho-position between PCB-209 and PCN-75 might be due to the difference of the π-conjugated plane caused by the dihedral angle of 90° and 0° of the two aromatic rings. Copyright © 2015 Elsevier Ltd. All rights reserved.

Detection of Interstellar Ortho-D2H+ with SOFIA

NASA Astrophysics Data System (ADS)

Harju, Jorma; Sipilä, Olli; Brünken, Sandra; Schlemmer, Stephan; Caselli, Paola; Juvela, Mika; Menten, Karl M.; Stutzki, Jürgen; Asvany, Oskar; Kamiński, Tomasz; Okada, Yoko; Higgins, Ronan

2017-05-01

We report on the detection of the ground-state rotational line of ortho-D2H+ at 1.477 THz (203 μm) using the German REceiver for Astronomy at Terahertz frequencies (GREAT) on board the Stratospheric Observatory For Infrared Astronomy (SOFIA). The line is seen in absorption against far-infrared continuum from the protostellar binary IRAS 16293-2422 in Ophiuchus. The para-D2H+ line at 691.7 GHz was not detected with the APEX telescope toward this position. These D2H+ observations complement our previous detections of para-H2D+ and ortho-H2D+ using SOFIA and APEX. By modeling chemistry and radiative transfer in the dense core surrounding the protostars, we find that the ortho-D2H+ and para-H2D+ absorption features mainly originate in the cool (T < 18 K) outer envelope of the core. In contrast, the ortho-H2D+ emission from the core is significantly absorbed by the ambient molecular cloud. Analyses of the combined D2H+ and H2D+ data result in an age estimate of ˜5 × 105 yr for the core, with an uncertainty of ˜2 × 105 yr. The core material has probably been pre-processed for another 5 × 105 years in conditions corresponding to those in the ambient molecular cloud. The inferred timescale is more than 10 times the age of the embedded protobinary. The D2H+ and H2D+ ions have large and nearly equal total (ortho+para) fractional abundances of ˜10-9 in the outer envelope. This confirms the central role of {{{H}}}3+ in the deuterium chemistry in cool, dense gas, and adds support to the prediction of chemistry models that also {{{D}}}3+ should be abundant in these conditions.

Photodissociation dynamics of the ortho- and para-xylyl radicals

NASA Astrophysics Data System (ADS)

Pachner, Kai; Steglich, Mathias; Hemberger, Patrick; Fischer, Ingo

2017-08-01

The photodissociation dynamics of the C8H9 isomers ortho- and para-xylyl are investigated in a free jet. The xylyl radicals are generated by flash pyrolysis from 2-(2-methylphenyl)- and 2-(4-methylphenyl) ethyl nitrite and are excited into the D3 state. REMPI- spectra show vibronic structure and the origin of the transition is identified at 32 291 cm-1 for the para- and at 32 132 cm-1 for the ortho-isomer. Photofragment H-atom action spectra show bands at the same energy and thus confirm H-atom loss from xylyl radicals. To gain further insight into the photodissociation dynamics, velocity map images of the hydrogen atom photofragments are recorded. Their angular distribution is isotropic and the translational energy release is in agreement with a dissociation to products in their electronic ground state. Photodissociation of para-xylyl leads to the formation of para-xylylene (C8H8), while the data for ortho-xylyl agree much better with the isomer benzocyclobutene as the dominant molecular fragment rather than ortho-xylylene. In computations we identified a new pathway for the reaction ortho-xylyl → benzocyclobutene + H with a barrier of 3.39 eV (27 340 cm-1), which becomes accessible at the employed excitation energy. It proceeds via a combination of scissoring and rotational motion of the -CH2 and -CH3 groups. However, the observed rate constants measured by delaying the excitation and ionization laser with respect to each other are significantly faster than computed ones, indicating intrinsic non-RRKM behaviour. A comparably high value of around 30% of the excess energy is released as translation of the H-atom photofragment.

Photodissociation dynamics of the ortho- and para-xylyl radicals.

PubMed

Pachner, Kai; Steglich, Mathias; Hemberger, Patrick; Fischer, Ingo

2017-08-28

The photodissociation dynamics of the C 8 H 9 isomers ortho- and para-xylyl are investigated in a free jet. The xylyl radicals are generated by flash pyrolysis from 2-(2-methylphenyl)- and 2-(4-methylphenyl) ethyl nitrite and are excited into the D 3 state. REMPI- spectra show vibronic structure and the origin of the transition is identified at 32 291 cm -1 for the para- and at 32 132 cm -1 for the ortho-isomer. Photofragment H-atom action spectra show bands at the same energy and thus confirm H-atom loss from xylyl radicals. To gain further insight into the photodissociation dynamics, velocity map images of the hydrogen atom photofragments are recorded. Their angular distribution is isotropic and the translational energy release is in agreement with a dissociation to products in their electronic ground state. Photodissociation of para-xylyl leads to the formation of para-xylylene (C 8 H 8 ), while the data for ortho-xylyl agree much better with the isomer benzocyclobutene as the dominant molecular fragment rather than ortho-xylylene. In computations we identified a new pathway for the reaction ortho-xylyl → benzocyclobutene + H with a barrier of 3.39 eV (27 340 cm -1 ), which becomes accessible at the employed excitation energy. It proceeds via a combination of scissoring and rotational motion of the -CH 2 and -CH 3 groups. However, the observed rate constants measured by delaying the excitation and ionization laser with respect to each other are significantly faster than computed ones, indicating intrinsic non-RRKM behaviour. A comparably high value of around 30% of the excess energy is released as translation of the H-atom photofragment.

Collisional excitation of sulfur dioxide by molecular hydrogen in warm molecular clouds

NASA Astrophysics Data System (ADS)

Balança, Christian; Spielfiedel, Annie; Feautrier, Nicole

2016-08-01

Interpretation of SO2 line emission in warm environments requires a detailed knowledge of collisional rate coefficients for a wide range of levels and temperatures. Using an accurate theoretical interaction potential for SO2-H2, rate coefficients for collisions of SO2 with para and ortho-H2 for the 31 first SO2, rotational levels are calculated for temperatures up to 500 K using the coupled states (CS) approximation. From a comparison with previously published close-coupling (CC) results, it was shown that the two sets of data agree within 20-30 per cent for both para- and ortho-H2 collisions. As previously found within the CC approach, the CS rate coefficients with ortho and para-H2 differ by a factor of 2 in average, the largest being mainly the rates for collisions with ortho-H2. For higher levels and temperatures, rate constants were computed within the infinite order sudden (IOS) approximation. Rate coefficients were obtained for the lowest 410 rotational levels of SO2 in the 100-1000 K temperature range. A comparison at 30, 100 and 300 K of the IOS data with the corresponding para-H2 CS results indicates that the IOS approximation systematically underestimates the CS results by a factor up to 2 at the lowest temperatures. As expected, IOS and CS rates are in a better agreement at higher temperatures. Considering that the IOS theory was developed for collisions with para-H2, this approach cannot describe with the same accuracy collisions with ortho-H2. So, our IOS data may be considered as quite reliable for collisions with para-H2 and less accurate for collisions with ortho-H2.

Direct 1H NMR evidence of spin-rotation coupling as a source of para → ortho-H2 conversion in diamagnetic solvents.

PubMed

Terenzi, Camilla; Bouguet-Bonnet, Sabine; Canet, Daniel

2017-04-21

At ambient temperature, conversion from 100% enriched para-hydrogen (p-H 2 ; singlet state) to ortho-hydrogen (o-H 2 ; triplet state) leads necessarily to the thermodynamic equilibrium proportions: 75% of o-H 2 and 25% of p-H 2 . When p-H 2 is dissolved in a diamagnetic organic solvent, conversion is very slow and can be considered as arising from nuclear spin relaxation phenomena. A first relaxation mechanism, specific to the singlet state and involving a combination of auto-correlation and cross correlation spectral densities, can be retained: randomly fluctuating magnetic fields due to inter-molecular dipolar interactions. We demonstrate here that (i) this dipolar mechanism is not sufficient for accounting for the para→ortho conversion rate, (ii) spin-rotation interaction, an intra-molecular mechanism, behaves similarly to random-field interaction and, thus, may be involved in the singlet relaxation rate. Also, as the para→ortho conversion is monitored by proton nuclear magnetic resonance (NMR) of dissolved o-H 2 (p-H 2 is NMR-silent), one has to account for H 2 exchange between the liquid phase and the gas phase within the NMR tube, as well as for dissolution effects. Experimental evidence of the above statements is brought here in the case of two organic solvents: acetone-d 6 and carbon disulfide. The observed temperature dependence of the para→ortho conversion rate shows that spin-rotation can be the dominant contribution to the p-H 2 relaxation rate in the absence of tangible dipolar interactions. Our findings shed new light on the "mysterious" mechanism of the para→ortho conversion which has been searched for several decades.

VizieR Online Data Catalog: Chemical reactions for a deuteration network (Vastel+, 2012)

NASA Astrophysics Data System (ADS)

Vastel, C.; Caselli, P.; Ceccarelli, C.; Bacmann, A.; Lis, D. C.; Caux, E.; Codella, C.; Beckwith, J. A.; Ridley, T.

2012-09-01

The ground-state rotational ortho-D2H+(1,1,1-0,0,0) transition at 1476.6GHz in the prestellar core 16293E has been searched for with the Herschel/HIFI instrument, within the CHESS (Chemical HErschel Surveys of Star forming regions) Key Program. The line has not been detected at the 21mK.km/s level (3 sigma integrated line intensity). We used the ortho-H2D+ 110-111 transition and para-D2H+ 110-101 transition detected in this source to determine an upper limit on the ortho-to-para D2H+ ratio as well as the para-D2H+/ortho-H2D+ ratio from a non-LTE analysis. We then compared our chemical modeling with the observations in order to estimate the CO depletion as well as the H2 density and kinetic temperature at the position observed. The chemical network is provided in the kida.dat file. (1 data file).

Isolation, Bioactivity, and Production of ortho-Hydroxydaidzein and ortho-Hydroxygenistein

PubMed Central

Chang, Te-Sheng

2014-01-01

Daidzein and genistein are two major components of soy isoflavones. They exist abundantly in plants and possess multiple bioactivities. In contrast, ortho-hydroxydaidzein (OHD) and ortho-hydroxygenistein (OHG), including 6-hydroxydaidzein (6-OHD), 8-hydroxydaidzein (8-OHD), 3′-hydroxydaidzein (3′-OHD), 6-hydroxygenistein (6-OHG), 8-hydroxygenistein (8-OHG), and 3′-hydroxygenistein (3′-OHG), are rarely found in plants. Instead, they are usually isolated from fermented soybean foods or microbial fermentation broth feeding with soybean meal. Accordingly, the bioactivity of OHD and OHG has been investigated less compared to that of soy isoflavones. Recently, OHD and OHG were produced by genetically engineering microorganisms through gene cloning of cytochrome P450 (CYP) enzyme systems. This success opens up bioactivity investigation and industrial applications of OHD and OHG in the future. This article reviews isolation of OHD and OHG from non-synthetic sources and production of the compounds by genetically modified microorganisms. Several bioactivities, such as anticancer and antimelanogenesis-related activities, of OHD and OHG, are also discussed. PMID:24705463

[Quantum differences of ortho/para H2O2 spin-isomers as a factor of the femtosecond charge separation kinetics modulation in reaction centers of purple bacteria].

PubMed

Pishchal'nikov, R Iu; Pershin, S M; Bunkin, A F

2012-01-01

We have proposed the mechanism of coherent modulations of the P* state in the transient absorption spectra of the reaction center isolated from purple bacteria. Two water molecules, located between special pair, Ba, Bb chlorophylls and histidine L173 and M202, are supposed to be ortho-H2O and para-H2O isomers with different magnetic properties. The distinctive modulation frequencies were labeling as rotational resonances of ortho-H2O. According to our assumption, the interaction of rotational modes of water isomers with the charge-transfer states is a reason of coherent modulations of kinetics. We have modified a Hamiltonian system in order to take into account the rotational modes of ortho-H2O. Evolution of the density matrix was calculated in Liouville space. The Redfield relaxation theory for molecular aggregates was used to model kinetics up to 3 ps.

Nitroxide paramagnet-induced para-ortho conversion and nuclear spin relaxation of H2 in organic solvents.

PubMed

Sartori, Elena; Ruzzi, Marco; Lawler, Ronald G; Turro, Nicholas J

2008-09-24

The kinetics of para-ortho conversion and nuclear spin relaxation of H 2 in chloroform- d 1 were investigated in the presence of nitroxides as paramagnetic catalysts. The back conversion from para-hydrogen ( p-H 2) to ortho-hydrogen ( o-H 2) was followed by NMR by recording the increase in the intensity of the signal of o-H 2 at regular intervals of time. The nitroxides proved to be hundreds of times more effective at inducing relaxation among the spin levels of o-H 2 than they are in bringing about transitions between p-H 2 and the levels of o-H 2. The value of the encounter distance d between H 2 and the paramagnetic molecule, calculated from the experimental bimolecular conversion rate constant k 0, using the Wigner theory of para-ortho conversion, agrees perfectly with that calculated from the experimental relaxivity R 1 using the force free diffusion theory of spin-lattice relaxation.

Infrared spectra of seeded hydrogen clusters: (para-H2)N-N2O and (ortho-H2)N-N2O, N = 2-13.

PubMed

Tang, Jian; McKellar, A R W

2005-09-15

High-resolution infrared spectra of clusters containing para-H2 and/or ortho-H2 and a single nitrous oxide molecule are studied in the 2225-cm(-1) region of the upsilon1 fundamental band of N2O. The clusters are formed in pulsed supersonic jet expansions from a cooled nozzle and probed using a tunable infrared diode laser spectrometer. The simple symmetric rotor-type spectra generally show no resolved K structure, with prominent Q-branch features for ortho-H2 but not para-H2 clusters. The observed vibrational shifts and rotational constants are reported. There is no obvious indication of superfluid effects for para-H2 clusters up to N=13. Sharp transitions due to even larger clusters are observed, but no definite assignments are possible. Mixed (para-H2)N-(ortho-H2)M-N2O cluster line positions can be well predicted by linear interpolation between the corresponding transitions of the pure clusters.

Rhodium(III)-Catalyzed ortho-Alkylation of Phenoxy Substrates with Diazo Compounds via C-H Activation: A Case of Decarboxylative Pyrimidine/Pyridine Migratory Cyclization Rather than Removal of Pyrimidine/Pyridine Directing Group.

PubMed

Ravi, Manjula; Allu, Srinivasarao; Swamy, K C Kumara

2017-03-03

An efficient Rh(III)-catalyzed ortho-alkylation of phenoxy substrates with diazo compounds has been achieved for the first time using pyrimidine or pyridine as the directing group. Furthermore, bis-alkylation has also been achieved using para-substituted phenoxypyrimidine and 3 mol equiv of the diazo ester. The ortho-alkylated derivatives of phenoxy products possessing the ester functionality undergo decarboxylative pyrimidine/pyridine migratory cyclization (rather than deprotection of pyrimidine/pyridine group) using 20% NaOEt in EtOH affording a novel class of 3-(pyrimidin-2(1H)-ylidene)benzofuran-2(3H)-ones and 6-methyl-3-(pyridin-2(1H)-ylidene)benzofuran-2(3H)-one. The ortho-alkylated phenoxypyridine possessing ester functionality also undergoes decarboxylative pyridine migratory cyclization using MeOTf/NaOMe in toluene providing 6-methyl-3-(1-methylpyridin-2(1H)-ylidene)benzofuran-2(3H)-one.

Assessing the Accuracy of Ortho-image using Photogrammetric Unmanned Aerial System

NASA Astrophysics Data System (ADS)

Jeong, H. H.; Park, J. W.; Kim, J. S.; Choi, C. U.

2016-06-01

Smart-camera can not only be operated under network environment anytime and any place but also cost less than the existing photogrammetric UAV since it provides high-resolution image, 3D location and attitude data on a real-time basis from a variety of built-in sensors. This study's proposed UAV photogrammetric method, low-cost UAV and smart camera were used. The elements of interior orientation were acquired through camera calibration. The image triangulation was conducted in accordance with presence or absence of consideration of the interior orientation (IO) parameters determined by camera calibration, The Digital Elevation Model (DEM) was constructed using the image data photographed at the target area and the results of the ground control point survey. This study also analyzes the proposed method's application possibility by comparing a Ortho-image the results of the ground control point survey. Considering these study findings, it is suggested that smartphone is very feasible as a payload for UAV system. It is also expected that smartphone may be loaded onto existing UAV playing direct or indirect roles significantly.

Upper limit for the D2H+ ortho-to-para ratio in the prestellar core 16293E (CHESS)

NASA Astrophysics Data System (ADS)

Vastel, C.; Caselli, P.; Ceccarelli, C.; Bacmann, A.; Lis, D. C.; Caux, E.; Codella, C.; Beckwith, J. A.; Ridley, T.

2012-11-01

The H_3^+ ion plays a key role in the chemistry of dense interstellar gas clouds where stars and planets are forming. The low temperatures and high extinctions of such clouds make direct observations of H_3^+ impossible, but lead to large abundances of H2D+ and D2H+, which are very useful probes of the early stages of star and planet formation. The ground-state rotational ortho-D2H+ 11,1-00,0 transition at 1476.6 GHz in the prestellar core 16293E has been searched for with the Herschel HIFI instrument, within the CHESS (Chemical HErschel Surveys of Star forming regions) Key Program. The line has not been detected at the 21 mK km s-1 level (3σ integrated line intensity). We used the ortho-H2D+ 11,0-11,1 transition and para-D2H+ 11,0-10,1 transition detected in this source to determine an upper limit on the ortho-to-para D2H+ ratio as well as the para-D2H+/ortho-H2D+ ratio from a non-local thermodynamic equilibrium analysis. The comparison between our chemical modeling and the observations suggests that the CO depletion must be high (larger than 100), with a density between 5 × 105 and 106 cm-3. Also the upper limit on the ortho-D2H+ line is consistent with a low gas temperature (~11 K) with a ortho-to-para ratio of 6 to 9, i.e. 2 to 3 times higher than the value estimated from the chemical modeling, making it impossible to detect this high frequency transition with the present state of the art receivers. The chemical network is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/547/A33Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Clinical efficacy of toric orthokeratology in myopic adolescent with moderate to high astigmatism.

PubMed

Luo, Ming; Ma, Shengsheng; Liang, Na

2014-12-01

To observe the efficacy of toric design orthokera- tology (ortho-k) for correcting myopia and astigmatism in myopic adolescents with moderate to high astigmatism. This was a self-controlled clinical study. Twenty-four subjects (42 eyes) aged 9 to 16 years with myopia of 2.50-6.00 D complicated with rule astigmatism of 1.50-3.50 D were fitted with Lucid Night Toric Ortho-k Lenses (LUCID,KO- REA). The changes in uncorrected visual acuity (UCVA), spherical degree, refraction, axial length (AL), and corneal status were assessed at baseline, 1 night, 1 week, 1 month, 3 months, 6 months, and 1 year after the commencement of ortho-k lens wear. The success rate of the first lens fit was 92.8%. The UCVA after ortho-k wearing was improved significantly compared to the baseline during each visit (all P < 0.01), and became stable 1 month after ortho-k. The manifest myopia was significantly reduced from (-3.41 ± 1.27) D to (-0.41 ± 0.37) D by toric ortho-k and the degree of astigmatism from (-1.81 ± 0.53)D to (-0.41 ± 0.39) D after 1 month of lens wear (P < 0.01). The mean AL was (24.47 ± 0.91) mm at baseline, which did not significantly differ from (24.49 ± 0.87) mm and (24.48 ± 0.94) mm after 6 months and 1 year, respectively, of lens wear (both P > 0.05). Grade 1 corneal staining was observed at 1 week (23.8%), 1 month (21.4%), and 1 year (16.7%) following lens wear, and was improved by lens cleaning, discontinuing lens wear, and moistening the cornea with eye drops. No severe adverse events were reported. The toric ortho-k lens was effective and safe for correction of low to moderate myopia in children with moderate to high astigmatism. The lens also effectively controlled axial length elongation during 1 year of observation. However, the long-term efficacy remains to be elucidated.

High Catalytic Efficiency of Nanostructured β-CoMoO₄ in the Reduction of the Ortho-, Meta- and Para-Nitrophenol Isomers.

PubMed

Al-Wadaani, Fahd; Omer, Ahmed; Abboudi, Mostafa; Oudghiri Hassani, Hicham; Rakass, Souad; Messali, Mouslim; Benaissa, Mohammed

2018-02-09

Nanostructured β-CoMoO₄ catalysts have been prepared via the thermal decomposition of an oxalate precursor. The catalyst was characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller method (BET), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The efficiency of these nanoparticles in the reduction of ortho - and meta -nitrophenol isomers (2-NP, 3-NP, and 4-NP) to their corresponding aminophenols was tested using UV-visible spectroscopy measurements. It was found that, with a β-CoMoO₄ catalyst, NaBH₄ reduces 3-NP instantaneously, whilst the reduction of 2-NP and 4-NP is slower at 8 min. This difference is thought to arise from the lower acidity of 3-NP, where the negative charge of the phenolate could not be delocalized onto the oxygen atoms of the meta-nitro group.

Spin-orbit quenching of the C+(2P) ion by collisions with para- and ortho-H2.

PubMed

Lique, François; Werfelli, Ghofran; Halvick, Philippe; Stoecklin, Thierry; Faure, Alexandre; Wiesenfeld, Laurent; Dagdigian, Paul J

2013-05-28

Spin-orbit (de-)excitation of C(+)((2)P) by collisions with H2, a key process for astrochemistry, is investigated. Quantum-mechanical calculations of collisions between C(+) ions and para- and ortho-H2 have been performed in order to determine the cross section for the C(+) (2)P3∕2 → (2)P1∕2 fine-structure transition at low and intermediate energies. The calculation are based on new ab initio potential energy surfaces obtained using the multireference configuration interaction method. Corresponding rate coefficients were obtained for temperatures ranging from 5 to 500 K. These rate coefficients are compared to previous estimations, and their impact is assessed through radiative transfer computation. They are found to increase the flux of the (2)P3∕2 → (2)P1∕2 line at 158 μm by up to 30% for typical diffuse interstellar cloud conditions.

Dispersion and interaction of graphene oxide in amorphous and semi-crystalline nano-composites: a PALS study

NASA Astrophysics Data System (ADS)

Maurer, Frans H. J.; Arza, Carlos R.

2015-06-01

The influence of dispersion and interaction of Graphene Oxide (GO) in semicrystalline Polyhydroxy butyrate (PHB) and glassy amorphous Poly(tBP-oda) is explored by Positron Annihilation Lifetime Spectroscopy (PALS). The ortho-Positronium lifetimes which represent the main free volume hole size of both polymers are mainly affected by the large differences in internal stresses built up by the shrinkage of the polymers during their preparation, restricted by the platelet structure of GO. The ortho-Positronium intensities, which represent the ortho-Positronium formation probabilities, suggest a strong dependency of on the dispersion of the nano-particles and their aspect ratio.

High lipophilicity of meta Mn(III) N-alkylpyridylporphyrin-based SOD mimics compensates for their lower antioxidant potency and makes them equally effective as ortho analogues in protecting SOD-deficient E. coli

PubMed Central

Kos, Ivan; Benov, Ludmil; Spasojević, Ivan; Rebouças, Júlio S.; Batinić-Haberle, Ines

2009-01-01

Lipophilicity/bioavailibility of Mn(III)N-alkylpyridylporphyrin-based SOD mimics has major impact on their in vivo ability to suppress oxidative stress. Meta isomers are less potent SOD mimics than ortho analogues, but are 10-fold more lipophilic and more planar. Enhanced lipophilicity contributes to their higher accumulation in cytosol of SOD-deficient E. coli, compensating for their lower potency; consequently both isomers exert similar-to-identical protection of SOD-deficient E. coli. Thus meta isomers may be as prospective therapeutics as are ortho porphyrins. PMID:19954250

Mapping the Apollo 17 Astronauts' Positions Based on LROC Data and Apollo Surface Photography

NASA Astrophysics Data System (ADS)

Haase, I.; Oberst, J.; Scholten, F.; Gläser, P.; Wählisch, M.; Robinson, M. S.

2011-10-01

The positions from where the Apollo 17 astronauts recorded panoramic image series, e.g. at the so-called "traverse stations", were precisely determined using ortho-images (0.5 m/pxl) as well as Digital Terrain Models (DTM) (1.5 m/pxl and 100 m/pxl) derived from Lunar Reconnaissance Orbiter Camera (LROC) data. Features imaged in the Apollo panoramas were identified in LROC ortho-images. Least-squares techniques were applied to angles measured in the panoramas to determine the astronaut's position to within the ortho-image pixel. The result of our investigation of Traverse Station 1 in the north-west of Steno Crater is presented.

Outer-Sphere Direction in Iridium C-H Borylation

PubMed Central

Roosen, Philipp C.; Kallepalli, Venkata A.; Chattopadhyay, Buddhadeb; Singleton, Daniel A.; Maleczka, Robert E.; Smith, Milton R.

2013-01-01

The NHBoc group affords ortho selective C–H borylations in arenes and alkenes. Experimental and computational studies support an outer sphere mechanism where the N–H proton hydrogen bonds to a boryl ligand oxygen. The regioselectivities are unique and complement those of directed ortho metalations. PMID:22703452

Improved Preparation of Halopropyl Bridged Carboxylic Ortho Esters

USDA-ARS?s Scientific Manuscript database

Protection of a carboxylic acid function as a bridged ortho ester derivative enables the use of strongly basic conditions in the synthetic strategy because the protons, alpha to the previous carbonyl carbon, are less acidic. Protected 3-halopropionic acid can behave like an alkyl halide making them...

Ultramap v3 - a Revolution in Aerial Photogrammetry

NASA Astrophysics Data System (ADS)

Reitinger, B.; Sormann, M.; Zebedin, L.; Schachinger, B.; Hoefler, M.; Tomasi, R.; Lamperter, M.; Gruber, B.; Schiester, G.; Kobald, M.; Unger, M.; Klaus, A.; Bernoegger, S.; Karner, K.; Wiechert, A.; Ponticelli, M.; Gruber, M.

2012-07-01

In the last years, Microsoft has driven innovation in the aerial photogrammetry community. Besides the market leading camera technology, UltraMap has grown to an outstanding photogrammetric workflow system which enables users to effectively work with large digital aerial image blocks in a highly automated way. Best example is the project-based color balancing approach which automatically balances images to a homogeneous block. UltraMap V3 continues innovation, and offers a revolution in terms of ortho processing. A fully automated dense matching module strives for high precision digital surface models (DSMs) which are calculated either on CPUs or on GPUs using a distributed processing framework. By applying constrained filtering algorithms, a digital terrain model can be derived which in turn can be used for fully automated traditional ortho texturing. By having the knowledge about the underlying geometry, seamlines can be generated automatically by applying cost functions in order to minimize visual disturbing artifacts. By exploiting the generated DSM information, a DSMOrtho is created using the balanced input images. Again, seamlines are detected automatically resulting in an automatically balanced ortho mosaic. Interactive block-based radiometric adjustments lead to a high quality ortho product based on UltraCam imagery. UltraMap v3 is the first fully integrated and interactive solution for supporting UltraCam images at best in order to deliver DSM and ortho imagery.

Rotational spectroscopic study of carbonyl sulfide solvated with hydrogen molecules.

PubMed

Michaud, Julie M; Jäger, Wolfgang

2008-10-14

Rotational spectra of small-sized (H(2))(N)-OCS clusters with N = 2-7 were measured using a pulsed-jet Fourier transform microwave spectrometer. These include spectra of pure (para-H(2))(N)-OCS clusters, pure (ortho-H(2))(N)-OCS clusters, and mixed ortho-H(2) and para-H(2) containing clusters. The rotational lines of ortho-H(2) molecules containing clusters show proton spin-proton spin hyperfine structure, and the pattern evolves as the number of ortho-H(2) molecules in the cluster increases. Various isotopologues of the clusters were investigated, including those with O(13)CS, OC(33)S, OC(34)S, and O(13)C(34)S. Nuclear quadrupole hyperfine structures of rotational transitions were observed for (33)S (nuclear spin quantum number I = 3/2) containing isotopologues. The (33)S nuclear quadrupole coupling constants are compared to the corresponding constant of the OCS monomer and those of the He(N)-OCS clusters. The assignment of the number of solvating hydrogen molecules N is supported by the analyses of the proton spin-proton spin hyperfine structures of the mixed clusters, the dependence of line intensities on sample conditions (pressure and concentrations), and the agreement of the (para-H(2))(N)-OCS and (ortho-H(2))(N)-OCS rotational constants with those from a previous infrared study [J. Tang and A. R. W. McKellar, J. Chem. Phys. 121, 3087 (2004)].

Herschel/HIFI⋆ observations of the circumstellar ammonia lines in IRC+10216

PubMed Central

Schmidt, M. R.; He, J. H.; Szczerba, R.; Bujarrabal, V.; Alcolea, J.; Cernicharo, J.; Decin, L.; Justtanont, K.; Teyssier, D.; Menten, K. M.; Neufeld, D. A.; Olofsson, H.; Planesas, P.; Marston, A. P.; Sobolev, A. M.; de Koter, A.; Schöier, F. L.

2016-01-01

Context A discrepancy exists between the abundance of ammonia (NH3) derived previously for the circumstellar envelope (CSE) of IRC+10216 from far-IR submillimeter rotational lines and that inferred from radio inversion or mid-infrared (MIR) absorption transitions. Aims To address the discrepancy described above, new high-resolution far-infrared (FIR) observations of both ortho- and para-NH3 transitions toward IRC+10216 were obtained with Herschel, with the goal of determining the ammonia abundance and constraining the distribution of NH3 in the envelope of IRC+10216. Methods We used the Heterodyne Instrument for the Far Infrared (HIFI) on board Herschel to observe all rotational transitions up to the J = 3 level (three ortho- and six para-NH3 lines). We conducted non-LTE multilevel radiative transfer modelling, including the effects of near-infrared (NIR) radiative pumping through vibrational transitions. The computed emission line profiles are compared with the new HIFI data, the radio inversion transitions, and the MIR absorption lines in the ν2 band taken from the literature. Results We found that NIR pumping is of key importance for understanding the excitation of rotational levels of NH3. The derived NH3 abundances relative to molecular hydrogen were (2.8 ± 0.5) × 10−8 for ortho-NH3 and (3.2−0.6+0.7)×10−8 for para-NH3, consistent with an ortho/para ratio of 1. These values are in a rough agreement with abundances derived from the inversion transitions, as well as with the total abundance of NH3 inferred from the MIR absorption lines. To explain the observed rotational transitions, ammonia must be formed near to the central star at a radius close to the end of the wind acceleration region, but no larger than about 20 stellar radii (1σ confidence level). PMID:28065983

78 FR 30270 - Foreign-Trade Zone (FTZ) 61-San Juan, Puerto Rico, Notification of Proposed Production Activity...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-22

... to various prescription and over-the-counter pharmaceutical products, including: Anti-cancer; anti..., Puerto Rico, Notification of Proposed Production Activity, Janssen Ortho LLC (Pharmaceutical Products... notification of proposed production activity to the FTZ Board on behalf of Janssen Ortho LLC (Janssen), located...

Cooling by Para-to-Ortho-Hydrogen Conversion

NASA Technical Reports Server (NTRS)

Sherman, A.; Nast, T.

1983-01-01

Catalyst speeds conversion, increasing capacity of solid hydrogen cooling system. In radial-flow catalytic converter, para-hydrogen is converted to equilibrium mixture of para-hydrogen and ortho-hydrogen as it passes through porous cylinder of catalyst. Addition of catalyst increases capacity of hydrogen sublimation cooling systems for radiation detectors.

78 FR 51733 - Draft Report on Carcinogens Monographs for ortho-Toluidine and Pentachlorophenol and By-Products...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-21

... Monographs for ortho-Toluidine and Pentachlorophenol and By-Products of Its Synthesis; Availability of... candidate substance is defined as ``pentachlorophenol and by-products of its synthesis.'' During synthesis of pentachlorophenol, several additional chlorinated molecules are formed as by-products. In addition...

New disinfection and sterilization methods.

PubMed Central

Rutala, W. A.; Weber, D. J.

2001-01-01

New disinfection methods include a persistent antimicrobial coating that can be applied to inanimate and animate objects (Surfacine), a high-level disinfectant with reduced exposure time (ortho-phthalaldehyde), and an antimicrobial agent that can be applied to animate and inanimate objects (superoxidized water). New sterilization methods include a chemical sterilization process for endoscopes that integrates cleaning (Endoclens), a rapid (4-hour) readout biological indicator for ethylene oxide sterilization (Attest), and a hydrogen peroxide plasma sterilizer that has a shorter cycle time and improved efficacy (Sterrad 50). PMID:11294738

Diastereoselective addition of anisoles to N-tert-butanesulfinyl imines via four-membered lithium cycles.

PubMed

Reddy, Leleti Rajender; Kotturi, Sharadsrikar; Waman, Yogesh; Patel, Chirag; Patwa, Aditya; Shenoy, Rajesh

2018-06-06

A highly regio- and diastereo-selective ortho-lithiation/addition of anisoles to N-tert-butanesulfinyl imines resulting in the selective formation of chiral α-branched amines is described. This method is also efficient for highly regioselective benzylic lithiation of o-methylanisoles, followed by diastereoselective addition to N-tert-butanesulfinyl imines.

Asymmetric Synthesis of Secondary and Tertiary Propargylic Alcohols by Umpolung of Acetylenic Sulfones and ortho-Sulfinyl Carbanions.

PubMed

Rodríguez, Ricardo I; Ramírez, Elsie; Yuste, Francisco; Sánchez-Obregón, Rubén; Alemán, José

2018-02-16

The generation of diastereomerically enriched secondary benzyl propargyl alcohols by the asymmetric addition of ortho-sulfinylbenzyl carbanions to sulfonylacetylene derivatives via formation of a Csp-Csp 3 bond is described. This reaction proceeds through an unusual α-attack (anti-Michael addition) of the ortho-sulfinylbenzyl carbanions, followed by elimination of the arylsulfonyl moiety. The scope of this alkynylation reaction is also discussed. Moreover, the development of a new approach for the synthesis of optically active tertiary benzylpropargyl alcohols is described, discussing the possible stereocourse of the reaction so as the influence of the ether 18-crown-6 and steric importance of acetylenic substituent.

78 FR 67371 - Draft Report on Carcinogens Monographs for ortho-Toluidine and Pentachlorophenol and By-products...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-12

... Monographs for ortho-Toluidine and Pentachlorophenol and By-products of Its Synthesis; Availability of... and By-products of its Synthesis (hereafter referred to as ``pentachlorophenol''). These documents were prepared by the Office of the Report on Carcinogens (ORoC), Division of the National Toxicology...

OrthoVenn: a web server for genome wide comparison and annotation of orthologous clusters across multiple species

USDA-ARS?s Scientific Manuscript database

Genome wide analysis of orthologous clusters is an important component of comparative genomics studies. Identifying the overlap among orthologous clusters can enable us to elucidate the function and evolution of proteins across multiple species. Here, we report a web platform named OrthoVenn that i...

The ortho:para-H_2 ratio in C- and J-type shocks

NASA Astrophysics Data System (ADS)

Wilgenbus, D.; Cabrit, S.; Pineau des Forêts, G.; Flower, D. R.

2000-04-01

We have computed extensive grids of models of both C- and J-type planar shock waves, propagating in dark, cold molecular clouds, in order to study systematically the behaviour of the ortho:para-H_2 ratio. Careful attention was paid to both macroscopic (dynamical) and microscopic (chemical reactions and collisional population transfer in H_2) aspects. We relate the predictions of the models to observational determinations of the ortho:para-H_2 ratio using both pure rotational lines and rovibrational lines. As an illustration, we consider ISO and ground-based H_2 observations of HH 54. Neither planar C-type nor planar J-type shocks appear able to account fully for these observations. Given the additional constraints provided by the observed ortho:para H_2 ratios, a C-type bowshock, or a C-type precursor followed by a J-type shock, remain as plausible models. Tables~2a-f and 4a-f are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

Titanium orthodontic brackets: structure, composition, hardness and ionic release.

PubMed

Gioka, Christiana; Bourauel, Christoph; Zinelis, Spiros; Eliades, Theodore; Silikas, Nikolaos; Eliades, George

2004-09-01

The aim of the present study was to investigate the composition, morphology, bulk structure and ionic release of two brands of titanium orthodontic brackets: Orthos2 (Ormco, USA) and Rematitan (Dentaurum, Germany). Five specimens of each group were examined with computerized X-ray microtomography, to reveal the morphology and structure of brackets, whilst resin-embedded and metallographically polished specimens were subjected to SEM/EDS analysis and Vickers microhardness measurements. Brackets were also maintained in 0.9% saline for 2 months and the ionic release in the immersion medium was determined with Inductively Coupled Plasma Atomic Emission Spectroscopy. The results of the hardness and ionic release measurements were statistically analyzed with two-way ANOVA and Tukey's test (alpha = 0.05). Orthos2 brackets consisted of two parts, the base (commercially pure Ti grade II) and the wing (Ti-6Al-4V alloy), joined together by laser welding, producing large gaps along the base-wing interface. The base was of lower hardness (Hv = 145), than the wing (Hv = 392) and incorporated a standard foil base-mesh pad. Rematitan brackets consisted of commercially pure Ti grade IV, with a single-piece manufacturing pattern of virtually identical hardness (p > 0.05) at the base and wings, featuring a laser-etched base-mesh pad. The hardness of the Rematitan brackets was significantly lower than the hardness of the Orthos2 wings, but double the hardness of the Orthos2 base. Released Ti levels were below the threshold level (1 ng/ml) of analysis for both materials, whilst traces of Al (3 ppm) and V (2 ppm) were found in the immersion media for Ti-6Al-4V alloy. The structural and hardness differences found may influence the torque transfer characteristics from activated archwires to the brackets and the crevice corrosion potential at the base-wing interface (Orthos2). The detection of Al and V in the immersion medium (Orthos2) may imply a different biological response from the two types of Ti brackets.

Phosphorus release from cyanobacterial blooms during their decline period in eutrophic Dianchi Lake, China.

PubMed

Zhang, Shenghua; Wang, Weilu; Zhang, Kaixiang; Xu, Peiyao; Lu, Yin

2018-05-01

The phosphorus (P) release from bloom-cyanobacterium during its decline period is one of the most important parts involved in lake P-biogeochemical cycle, which is an important nutrient self-regulating process to sustain eutrophic status in lakes. An in situ experiment was set up to study the phosphorus release mechanisms of cyanobacterial blooms in Dianchi Lake during its decline period. In the enclosure, the cyanobacteria were dying out gradually and this process further affected the water quality parameters and lead to P release from bloom-cyanobacteria. The pH and electric conductivity (EC) increased substantially, while the redox potential (ORP) decreased during the whole experimental period. Among all the released P forms, the orthophosphate (ortho-P) was the main released P form and accounted for 96.7 and 67.8% of the total phosphorus (TP) increment in the water and the TP reduction in algae respectively. According to the TP in sediment and lost P of overlying water column, it could be concluded that the ortho-P released from algae was absorbed by sediment as well. The release of TP, organic P (OP), and ortho-P from bloom-cyanobacteria all followed the first-order kinetics, and the release rate of ortho-P was much higher than that of OP (p < 0.05). Furthermore, according to the total extracellular polysaccharide (EPS) determination and related Pearson's correlation analysis, the release of TP and ortho-P from bloom-cyanobacteria would probably depend on the reduction of capsular polysaccharide (CPS) and colonial sheath disaggregation. In conclusion, a large amount of ortho-P was released and adsorbed by sediment gradually during cyanobacterial bloom decline period, and these bioavailable P could provide the sufficient nutrient for newborn cyanobacteria and could contribute to the construction of a new internal P cycle among sediment, water, and cyanobacterial bloom.

Loss of benzene to generate an enolate anion by a site-specific double-hydrogen transfer during CID fragmentation of o-alkyl ethers of ortho-hydroxybenzoic acids.

PubMed

Attygalle, Athula B; Bialecki, Jason B; Nishshanka, Upul; Weisbecker, Carl S; Ruzicka, Josef

2008-09-01

Collision-induced dissociation of anions derived from ortho-alkyloxybenzoic acids provides a facile way of producing gaseous enolate anions. The alkyloxyphenyl anion produced after an initial loss of CO(2) undergoes elimination of a benzene molecule by a double-hydrogen transfer mechanism, unique to the ortho isomer, to form an enolate anion. Deuterium labeling studies confirmed that the two hydrogen atoms transferred in the benzene loss originate from positions 1 and 2 of the alkyl chain. An initial transfer of a hydrogen atom from the C-1 position forms a phenyl anion and a carbonyl compound, both of which remain closely associated as an ion/neutral complex. The complex breaks either directly to give the phenyl anion by eliminating the neutral carbonyl compound, or to form an enolate anion by transferring a hydrogen atom from the C-2 position and eliminating a benzene molecule in the process. The pronounced primary kinetic isotope effect observed when a deuterium atom is transferred from the C-1 position, compared to the weak effect seen for the transfer from the C-2 position, indicates that the first transfer is the rate determining step. Quantum mechanical calculations showed that the neutral loss of benzene is a thermodynamically favorable process. Under the conditions used, only the spectra from ortho isomers showed peaks at m/z 77 for the phenyl anion and m/z 93 for the phenoxyl anion, in addition to that for the ortho-specific enolate anion. Under high collision energy, the ortho isomers also produce a peak at m/z 137 for an alkene loss. The spectra of meta and para compounds show a peak at m/z 92 for the distonic anion produced by the homolysis of the O-C bond. Moreover, a small peak at m/z 136 for a distonic anion originating from an alkyl radical loss allows the differentiation of para compounds from meta isomers.

Quantifying reactivity for electrophilic aromatic substitution reactions with Hirshfeld charge.

PubMed

Liu, Shubin

2015-03-26

An electrophilic aromatic substitution is a process where one atom or group on an aromatic ring is replaced by an incoming electrophile. The reactivity and regioselectivity of this category of reactions is significantly impacted by the group that is already attached to the aromatic ring. Groups promoting substitution at the ortho/para and meta position are called ortho/para and meta directing groups, respectively. Earlier, we have shown that regioselectivity of the electrophilic aromatic substitution is dictated by the nucleophilicity of the substituted aromatic ring, which is proportional to the Hirshfeld charge on the regioselective site. Ortho/para directing groups have the largest negative charge values at the ortho/para positions, whereas meta directing groups often have the largest negative charge value at the meta position. The electron donation or acceptance feature of a substitution group is irrelevant to the regioselectivity. In this contribution, we extend our previous study by quantifying the reactivity for this kind of reactions. To that end, we examine the transition-state structure and activation energy of an identity reaction for a series of monosubstituted-benzene molecules reacting with hydrogen fluoride using BF3 as the catalyst in the gas phase. A total of 18 substitution groups will be considered, nine of which are ortho/para directing and the other nine groups meta directing. From this study, we found that the barrier height of these reactions strongly correlates with the Hirshfeld charge on the regioselective site for both ortho/para and meta directing groups, with the correlation coefficient R(2) both better than 0.96. We also discovered a less accurate correlation between the barrier height and HOMO energy. These results reconfirm the validity and effectiveness of employing the Hirshfeld charge as a reliable descriptor of both reactivity and regioselectivity for this vastly important category of chemical transformations.

The control effect of orthokeratology on axial length elongation in Chinese children with myopia.

PubMed

Zhu, Meng-Jun; Feng, Hao-Yan; He, Xian-Gui; Zou, Hai-Dong; Zhu, Jian-Feng

2014-11-24

To retrospectively compare axial elongation in children with different degrees of myopia wearing spectacles and undergoing ortho-k treatment. The medical records of 128 patients who were fitted with spectacles or orthokeratology (ortho-k) lenses in our clinic between 2008 and 2009 were reviewed. Ortho-k group comprised 65 subjects and 63 subjects wearing spectacles were included in the control group. Subjects were also divided into low-myopia, moderate-myopia and high-myopia groups, based on the basic spherical equivalent refractive error. Axial length periodically measured over 2-year of lens wear and changes in axial length were compared between treatment groups and between subgroups with different degrees of myopia. The control group exhibited more changes in axial length than the ortho-k group at both 12 months (0.39 ± 0.21 mm vs 0.16 ± 0.17 mm, p <0.001) and 24 months (0.70 ± 0.35 mm vs 0.34 ± 0.29 mm, p <0.001). Axial length elongation was estimated to be slower by about 51% in the ortho-k group. Similar results were found for the subgroups (49%, 59% and 46% reductions, respectively). In the group with low and moderate myopia, the annual increases in axial length were significantly different between the ortho-k and control groups during both the first ( Low myopia: 0.19 ± 0.17 mm vs 0.40 ± 0.18 mm, p = 0.001; Moderate myopia: 0.14 ± 0.18 mm vs 0.45 ± 0.22 mm, p <0.001) and second ( Low myopia: 0.18 ± 0.14 mm vs 0.32 ± 0.19 mm, p = 0.012; Moderate myopia: 0.18 ± 0.16 mm vs 0.34 ± 0.30 mm, p = 0.030) years. In the high myopia groups, significant differences were only found between the ortho-k and control groups during the first year (0.16 ± 0.18 mm vs 0.34 ± 0.22 mm, p = 0.004). The 2-year axial elongation was significantly associated with initial age (p <0.001) and treatment (p <0.001), but not with gender, initial refractive error, initial axial length, initial corneal curvature. This 2-year study indicates that ortho-k contact lens wear is effective for reducing myopia progression in children with low, moderate and high myopia.

Chlorination of 2-phenoxypropanoic acid with NCP in aqueous acetic acid: using a novel ortho-para relationship and the para/meta ratio of substituent effects for mechanism elucidation.

PubMed

Segurado, Manuel A P; Reis, João Carlos R; de Oliveira, Jaime D Gomes; Kabilan, Senthamaraikannan; Shanthi, Manohar

2007-07-06

Rate constants were measured for the oxidative chlorodehydrogenation of (R,S)-2-phenoxypropanoic acid and nine ortho-, ten para- and five meta-substituted derivatives using (R,S)-1-chloro-3-methyl-2,6-diphenylpiperidin-4-one (NCP) as chlorinating agent. The kinetics was run in 50% (v/v) aqueous acetic acid acidified with perchloric acid under pseudo-first-order conditions with respect to NCP at temperature intervals of 5 K between 298 and 318 K, except at the highest temperature for the meta derivatives. The dependence of rate constants on temperature was analyzed in terms of the isokinetic relationship (IKR). For the 20 reactions studied at five different temperatures, the isokinetic temperature was estimated to be 382 K, which suggests the preferential involvement of water molecules in the rate-determining step. The dependence of rate constants on meta and para substitution was analyzed using the tetralinear extension of the Hammett equation. The parameter lambda for the para/meta ratio of polar substituent effects was estimated to be 0.926, and its electrostatic modeling suggests the formation of an activated complex bearing an electric charge near the oxygen atom belonging to the phenoxy group. A new approach is introduced for examining the effect of ortho substituents on reaction rates. Using IKR-determined values of activation enthalpies for a set of nine pairs of substrates with a given substituent, a linear correlation is found between activation enthalpies of ortho and para derivatives. The correlation is interpreted in terms of the selectivity of the reactant toward para- or ortho-monosubstituted substrates, the slope of which being related to the ortho effect. This slope is thought to be approximated by the ratio of polar substituent effects from ortho and para positions in benzene derivatives. Using the electrostatic theory of through-space interactions and a dipole length of 0.153 nm, this ratio was calculated at various positions of a charged reaction center along the benzene C1-C4 axis, being about 2.5 near the ring and decreasing steeply with increasing distance until reaching a minimum value of -0.565 at 1.3 nm beyond the aromatic ring. Activation enthalpies and entropies were estimated for substrates bearing the isoselective substituent in either ortho and para positions, being demonstrated that they are much different from the values for the parent substrate. The electrophilic attack on the phenolic oxygen atom by the protonated chlorinating agent is proposed as the rate-determining step, this step being followed by the fast rearrangement of the intermediate thus formed, leading to products containing chlorine in the aromatic ring.

Comparison of glutathione levels measured using optimized monochlorobimane assay with those from ortho-phthalaldehyde assay in intact cells.

PubMed

Čapek, Jan; Hauschke, Martina; Brůčková, Lenka; Roušar, Tomáš

2017-11-01

Fluorometric glutathione assays have been generally preferred for their high specificity and sensitivity. An additional advantage offered by fluorescent bimane dyes is their ability to penetrate inside the cell. Their ability to react with glutathione within intact cells is frequently useful in flow cytometry and microscopy. Hence, the aims of our study were to use monochlorobimane for optimizing a spectrofluorometric glutathione assay in cells and then to compare that assay with the frequently used ortho-phthalaldehyde assay. We used glutathione-depleting agents (e.g., cisplatin and diethylmalonate) to induce cell impairment. For glutathione assessment, monochlorobimane (40μM) was added to cells and fluorescence was detected at 394/490nm. In addition to the regularly used calculation of glutathione levels from fluorescence change after 60min, we used an optimized calculation from the linear part of the fluorescence curve after 10min of measurement. We found that 10min treatment of cells with monochlorobimane is sufficient for evaluating cellular glutathione concentration and provides results entirely comparable with those from the standard ortho-phthalaldehyde assay. In contrast, the results obtained by the standardly used evaluation after 60min of monochlorobimane treatment provided higher glutathione values. We conclude that measuring glutathione using monochlorobimane with the here-described optimized evaluation of fluorescence signal could be a simple and useful method for routine and rapid assessment of glutathione within intact cells in large numbers of samples. Copyright © 2017 Elsevier Inc. All rights reserved.

Identification of ortho-Substituted Benzoic Acid/Ester Derivatives via the Gas-Phase Neighboring Group Participation Effect in (+)-ESI High Resolution Mass Spectrometry.

PubMed

Blincoe, William D; Rodriguez-Granillo, Agustina; Saurí, Josep; Pierson, Nicholas A; Joyce, Leo A; Mangion, Ian; Sheng, Huaming

2018-04-01

Benzoic acid/ester/amide derivatives are common moieties in pharmaceutical compounds and present a challenge in positional isomer identification by traditional tandem mass spectrometric analysis. A method is presented for exploiting the gas-phase neighboring group participation (NGP) effect to differentiate ortho-substituted benzoic acid/ester derivatives with high resolution mass spectrometry (HRMS 1 ). Significant water/alcohol loss (>30% abundance in MS 1 spectra) was observed for ortho-substituted nucleophilic groups; these fragment peaks are not observable for the corresponding para and meta-substituted analogs. Experiments were also extended to the analysis of two intermediates in the synthesis of suvorexant (Belsomra) with additional analysis conducted with nuclear magnetic resonance (NMR), density functional theory (DFT), and ion mobility spectrometry-mass spectrometry (IMS-MS) studies. Significant water/alcohol loss was also observed for 1-substituted 1, 2, 3-triazoles but not for the isomeric 2-substituted 1, 2, 3-triazole analogs. IMS-MS, NMR, and DFT studies were conducted to show that the preferred orientation of the 2-substituted triazole rotamer was away from the electrophilic center of the reaction, whereas the 1-subtituted triazole was oriented in close proximity to the center. Abundance of NGP product was determined to be a product of three factors: (1) proton affinity of the nucleophilic group; (2) steric impact of the nucleophile; and (3) proximity of the nucleophile to carboxylic acid/ester functional groups. Graphical Abstract ᅟ.

An In-vitro Comparison of Force Loss of Orthodontic Non-Latex Elastics

PubMed Central

Alavi, Shiva; Tabatabaie, Atusa Rahnama; Hajizadeh, Fatemeh; Ardekani, Alireza Haerian

2014-01-01

Objective: The amount and consistency of the applied forces to the tooth are important factors in tooth movements; therefore, the aim of this study was to compare the initial force and the force loss of three brands of elastics in 24 hours. Materials and Methods: In this in-vitro study sixty non-latex elastics (3/16 medium) from three companies (Forestadent, Dentaurum and Ortho Technology) were randomly selected. Two static tests were performed, the first in a dry environment to evaluate the initial force and the other performed in a wet environment (artificial saliva) to evaluate the force loss in 24 hours. The Universal testing machine measured the forces after stretching the elastics to three times the lumen diameter. Data were analyzed by repeated measures ANOVA, One-way ANOVA, Tukey-HSD, Paired samples test, and one sample test. Results: The difference between the brands was significant (p=0.002). Force loss was observed in all samples; 4–7.5% force loss occurred after one hour and 19–38% force loss occurred after 24 hours. The average initial force of Forestadent and Ortho Technology was significantly higher than marketed forces (p<0.001), but the initial force of Dentaurum elastics was similar to the marketed force. Conclusion: The force loss over 24 hours time period was Forestadent>Dentaurum>Ortho-Technology. According to the initial force and force loss percentage it is suggested to replace the non-latex elastics several times a day. PMID:24910671

Identification of ortho-Substituted Benzoic Acid/Ester Derivatives via the Gas-Phase Neighboring Group Participation Effect in (+)-ESI High Resolution Mass Spectrometry

NASA Astrophysics Data System (ADS)

Blincoe, William D.; Rodriguez-Granillo, Agustina; Saurí, Josep; Pierson, Nicholas A.; Joyce, Leo A.; Mangion, Ian; Sheng, Huaming

2018-02-01

Benzoic acid/ester/amide derivatives are common moieties in pharmaceutical compounds and present a challenge in positional isomer identification by traditional tandem mass spectrometric analysis. A method is presented for exploiting the gas-phase neighboring group participation (NGP) effect to differentiate ortho-substituted benzoic acid/ester derivatives with high resolution mass spectrometry (HRMS1). Significant water/alcohol loss (>30% abundance in MS1 spectra) was observed for ortho-substituted nucleophilic groups; these fragment peaks are not observable for the corresponding para and meta-substituted analogs. Experiments were also extended to the analysis of two intermediates in the synthesis of suvorexant (Belsomra) with additional analysis conducted with nuclear magnetic resonance (NMR), density functional theory (DFT), and ion mobility spectrometry-mass spectrometry (IMS-MS) studies. Significant water/alcohol loss was also observed for 1-substituted 1, 2, 3-triazoles but not for the isomeric 2-substituted 1, 2, 3-triazole analogs. IMS-MS, NMR, and DFT studies were conducted to show that the preferred orientation of the 2-substituted triazole rotamer was away from the electrophilic center of the reaction, whereas the 1-subtituted triazole was oriented in close proximity to the center. Abundance of NGP product was determined to be a product of three factors: (1) proton affinity of the nucleophilic group; (2) steric impact of the nucleophile; and (3) proximity of the nucleophile to carboxylic acid/ester functional groups. [Figure not available: see fulltext.

78 FR 30862 - Foreign-Trade Zone 61-San Juan, Puerto Rico; Application for Subzone; Janssen Ortho LLC; Gurabo...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-23

..., Puerto Rico; Application for Subzone; Janssen Ortho LLC; Gurabo, Puerto Rico An application has been submitted to the Foreign-Trade Zones Board (the Board) by the Puerto Rico Trade & Export Company, grantee of... Gurabo, Puerto Rico. The application was submitted pursuant to the provisions of the Foreign-Trade Zones...

FipsOrtho: A Spell Checker for Learners of French

ERIC Educational Resources Information Center

L'Haire, Sebastien

2007-01-01

This paper presents FipsOrtho, a spell checker targeted at learners of French, and a corpus of learners' errors which has been gathered to test the system and to get a sample of specific language learners' errors. Spell checkers are a standard feature of many software products, however they are not designed for specific language learners' errors.…

Nucleophilic ortho-Allylation of Pyrroles and Pyrazoles: An Accelerated Pummerer/Thio-Claisen Rearrangement Sequence

PubMed Central

2013-01-01

Arylsulfinyl groups direct the metal-free, regiospecific, nucleophilic ortho-allylation of pyrroles and pyrazoles. Mechanistic studies support the intermediacy of allylsulfonium salts that undergo facile thio-Claisen rearrangement onto the heterocyclic ring, giving products of coupling. The strategy has been adapted to allow regiospecific propargylation of the heterocyclic substrates. PMID:23855635

Regioselective desymmetrization of diaryltetrahydrofurans via directed ortho-lithiation: an unexpected help from green chemistry.

PubMed

Mallardo, Valentina; Rizzi, Ruggiero; Sassone, Francesca C; Mansueto, Rosmara; Perna, Filippo M; Salomone, Antonio; Capriati, Vito

2014-08-14

An efficient functionalization of diaryltetrahydrofurans via a regioselective THF-directed ortho-lithiation is first described. This reaction can be successfully carried out in cyclopentyl methyl ether as a "greener" alternative to Et2O, with better results in terms of yield and selectivity and, surprisingly, also in protic eutectic mixtures competitively with protonolysis.

EVALUATION OF THE TERATOGENIC EFFECTS OF TRI-ORTHO-CRESYL PHOSPHATE IN THE LONG-EVANS HOODED RAT

EPA Science Inventory

The developmental toxicity of tri-ortho-cresyl phosphate (TOCP) was evaluated in Long-Evans rats. Pregnant rats were treated with 87.5, 175, and 350 mg/kg/day TOCP throughout organogenesis from gestation day 6 through 18 (day of sperm = day 0). The highest dose tested (350 mg/kg)...

Electric Hindrance and Precursor Complexes in the Regiochemistry of Some Nitrations

ERIC Educational Resources Information Center

Sanchez-Viesca, Francisco; Gomez, Maria Reina Gomez; Berros, Martha

2011-01-01

There are still gaps in the theory of supposedly well-known chemical reactions. For example, there is no explanation why there is a notorious preponderance of one of the expected isomers in some electrophilic aromatic substitutions. The preferred ortho orientation of acetyl nitrate has been used widely to obtain ortho nitro compounds; however,…

AN IP3 RECEPTOR-SENSITIVE CALCIUM STORE MEDIATES DISTURBANCES IN INTRACELLULAR CALCIUM UPON EXPOSURE TO AROCLOR 1254 AND ORTHO-SUBSTITUTED PCBS.

EPA Science Inventory

An IP3 Receptor-Sensitive Ca2+ Store Mediates Disturbances In Intracellular Ca2+ Upon Exposure To Aroclor 1254 And Ortho-Substituted PCBs JR Inglefield, WR Mundy, and TJ Shafer. Neurotoxicol. Div., NHEERL, US EPA, RTP, NC. Sponsor: L Birnbaum

Polychlorinated biphenyls (...

A new synthetic route to the preparation of a series of strong photoreducing agents: fac Tris-ortho-metalated complexes of iridium(III) with substituted 2-phenylpyridines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Y.; Baer, C.D.; Camaioni-Neto, C.

1991-04-17

A new procedure is reported for the high-yield synthesis of fac-tris-ortho-metalated complexes of Ir(III) with 2-phenylpyridine (Hppy) and with substituted 2-phenylpyridine (R-Hppy) ligands. The reported procedure uses the Ir(III) starting material Ir(acac){sub 3} (acac = 2,4-pentanedionate) and typically produces the fac-tris-ortho-metalated complexes in yields of 40-75%. Each of the complexes formed with substituted phenylpyridines exhibited a luminescence lifetime of approximately 2-5 microseconds in nitrogen-saturated acetonitrile at room temperature, and each complex is characterized by a reversible oxidative wave in cyclic voltammetry in acetonitrile. 42 refs., 1 fig., 1 tab.

Reaction of formaldehyde at the ortho- and para-positions of phenol: exploration of mechanisms using computational chemistry.

Treesearch

Anthony H. Conner; Melissa S. Reeves

2001-01-01

Computational chemistry methods can be used to explore the theoretical chemistry behind reactive systems, to compare the relative chemical reactivity of different systems, and, by extension, to predict the reactivity of new systems. Ongoing research has focused on the reactivity of a wide variety of phenolic compounds with formaldehyde using semi-empirical and ab...

A Combination of Chemometrics and Quantum Mechanics Methods Applied to Analysis of Femtosecond Transient Absorption Spectrum of Ortho-Nitroaniline

PubMed Central

Yi, Jing; Xiong, Ying; Cheng, Kemei; Li, Menglong; Chu, Genbai; Pu, Xuemei; Xu, Tao

2016-01-01

A combination of the advanced chemometrics method with quantum mechanics calculation was for the first time applied to explore a facile yet efficient analysis strategy to thoroughly resolve femtosecond transient absorption spectroscopy of ortho-nitroaniline (ONA), served as a model compound of important nitroaromatics and explosives. The result revealed that the ONA molecule is primarily excited to S3 excited state from the ground state and then ultrafast relaxes to S2 state. The internal conversion from S2 to S1 occurs within 0.9 ps. One intermediate state S* was identified in the intersystem crossing (ISC) process, which is different from the specific upper triplet receiver state proposed in some other nitroaromatics systems. The S1 state decays to the S* one within 6.4 ps and then intersystem crossing to the lowest triplet state within 19.6 ps. T1 was estimated to have a lifetime up to 2 ns. The relatively long S* state and very long-lived T1 one should play a vital role as precursors to various nitroaromatic and explosive photoproducts. PMID:26781083

Spectroscopic, potentiometric and theoretical studies on the binding properties of a novel tripodal polycatechol-imine ligand towards iron(III)

NASA Astrophysics Data System (ADS)

Kanungo, B. K.; Sahoo, Suban K.; Baral, Minati

2008-12-01

A novel multidentate tripodal ligand, cis, cis-1,3,5-tris[(2,3-dihydroxybenzylidene)aminomethyl]cyclohexane (TDBAC, L) containing one catechol unit in each arms of a tripodal amine, cis, cis-1,3,5-tris(aminomethyl)cyclohexane was investigated as a chelator for iron(III) through potentiometric and spectrophotometric methods in an aqueous medium of 0.1N ionic strength and 25 ± 1 °C as well as in ethanol by continuous variation method. From pH metric in water, three protonation constants characterized for the three-hydroxyl groups of the catechol units at ortho were used as input data to evaluate the stability constants of the complexes. Formation of monomeric complexes FeLH 3, FeLH 2, FeLH and FeL were depicted. In ethanol, formation of complexes FeL, Fe 2L and Fe 3L were characterized. Structures of the complexes were explained by using the experimental evidences and predicted through molecular modeling calculations. The ligand showed potential to coordinate iron(III) through three imine nitrogens and three catecholic oxygens at ortho to form a tris(iminocatecholate) type complex.

Optimization of media components for laccase production by litter dwelling fungal isolate Fusarium incarnatum LD-3.

PubMed

Chhaya, Urvish; Gupte, Akshaya

2010-02-01

Laccase production by solid state fermentation (SSF) using an indigenously isolated litter dwelling fungus Fusarium incarnatum LD-3 was optimized. Fourteen medium components were screened by the initial screening method of Plackett-Burman. Each of the components was screened on the basis of 'p' (probability value) which was above 95% confidence level. Ortho-dianisidine, thiamine HCl and CuSO(4) . 5 H(2)O were identified as significant components for laccase production. The Central Composite Design response surface methodology was then applied to further optimize the laccase production. The optimal concentration of these three medium components for higher laccase production were (g/l): CuSO(4) . 5 H(2)O, 0.01; thiamine HCl, 0.0136 and ortho-dianisidine, 0.388 mM served as an inducer. Wheat straw, 5.0 g was used as a solid substrate. Using this statistical optimization method the laccase production was found to increase from 40 U/g to 650 U/g of wheat straw, which was sixteen times higher than non optimized medium. This is the first report on statistical optimization of laccase production from Fusarium incarnatum LD-3.

Assessing a potential solution for spatially referencing of historical aerial photography in South Africa

NASA Astrophysics Data System (ADS)

Denner, Michele; Raubenheimer, Jacobus H.

2018-05-01

Historical aerial photography has become a valuable commodity in any country, as it provides a precise record of historical land management over time. In a developing country, such as South Africa, that has undergone enormous political and social change over the last years, such photography is invaluable as it provides a clear indication of past injustices and serves as an aid to addressing post-apartheid issues such as land reform and land redistribution. National mapping organisations throughout the world have vast repositories of such historical aerial photography. In order to effectively use these datasets in today's digital environment requires that it be georeferenced to an accuracy that is suitable for the intended purpose. Using image-to-image georeferencing techniques, this research sought to determine the accuracies achievable for ortho-rectifying large volumes of historical aerial imagery, against the national standard for ortho-rectification in South Africa, using two different types of scanning equipment. The research conducted four tests using aerial photography from different time epochs over a period of sixty years, where the ortho-rectification matched each test to an already ortho-rectified mosaic of a developed area of mixed land use. The results of each test were assessed in terms of visual accuracy, spatial accuracy and conformance to the national standard for ortho-rectification in South Africa. The results showed a decrease in the overall accuracy of the image as the epoch range between the historical image and the reference image increased. Recommendations on the applications possible given the different epoch ranges and scanning equipment used are provided.

Health risk assessment of exposure to TriCresyl Phosphates (TCPs) in aircraft: a commentary.

PubMed

de Ree, Hans; van den Berg, Martin; Brand, Teus; Mulder, Gerard J; Simons, Ries; Veldhuijzen van Zanten, Brinio; Westerink, Remco H S

2014-12-01

Possible exposure to TriCresyl Phosphates (TCPs) has led to concerns among airline crew members. One isomer, Tri-ortho-Cresyl Phosphate (ToCP) is known to be neurotoxic and exposure to ToCP via contaminated cabin air has been suggested to be associated with the alleged Aerotoxic syndrome. The symptoms associated with Aerotoxic syndrome are diverse, including headaches, loss of balance, numbness and neurobehavioral abnormalities such as emotional instability, depression and cognitive dysfunction. Other ortho-isomers are toxic as well, but the non-ortho isomers are regarded as less toxic. In a collaborative effort to increase insight into the possible association between exposure to TCPs via contaminated cabin air and Aerotoxic syndrome, we performed an exposure- and toxicological risk assessment. Measurements in KLM 737 aircraft have demonstrated the presence of non-ortho isomers in low concentrations, though ToCP and other ortho-isomers could not be detected. Based on this exposure assessment, we established a toxicological risk model that also takes into account human differences in bioactivation and detoxification to derive a hazard quotient. From this model it appears unlikely that the health effects and alleged Aerotoxic syndrome are due to exposure to ToCP. Alternative explanations for the reported symptoms are discussed, but evaluation of the current findings in light of the criteria for occupational disease leads to the conclusion that the Aerotoxic Syndrome cannot be regarded as such. Additional research is thus required to unravel the underlying causes for the reported health complaints. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of incorporation of nano-fluorapatite or nano-fluorohydroxyapatite on a resin-modified glass ionomer cement.

PubMed

Lin, Jun; Zhu, Jiajun; Gu, Xiaoxia; Wen, Wenjian; Li, Qingshan; Fischer-Brandies, Helge; Wang, Huiming; Mehl, Christian

2011-03-01

This study aimed to investigate the fluoride release properties and the effect on bond strength of two experimental adhesive cements. Synthesized particles of nano-fluorapatite (nano-FA) or nano-fluorohydroxyapatite (nano-FHA) were incorporated into a resin-modified glass ionomer cement (Fuji Ortho LC) and characterized using X-ray diffraction and scanning electron microscopy. Blocks with six different concentrations of nano-FA or nano-FHA were manufactured and their fluoride release properties evaluated by ultraviolet spectrophotometry. The unaltered glass ionomer cement Fuji Ortho LC (GC, control) and the two experimental cements with the highest fluoride release capacities (nano-FA+Fuji Ortho LC (GFA) and nano-FHA+Fuji Ortho LC (GFHA)) were used to bond composite blocks and orthodontic brackets to human enamel. After 24 h water storage all specimens were debonded, measuring the micro-tensile bond strength (μTBS) and the shear bond strength (SBS), respectively. The optimal concentration of added nano-FA and nano-FHA for maximum fluoride release was 25 wt.%, which nearly tripled fluoride release after 70 days compared with the control group. GC exhibited a significantly higher SBS than GFHA/GFA, with GFHA and GFA not differing significantly (P>0.05). The μTBS of GC and GFA were significantly higher than that of GFHA (P≤0.05). The results seem to indicate that the fluoride release properties of Fuji Ortho LC are improved by incorporating nano-FA or nano-FHA, simultaneously maintaining a clinically sufficient bond strength when nano-FA was added. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Discontinuation of orthokeratology on eyeball elongation (DOEE).

PubMed

Cho, P; Cheung, S W

2017-04-01

To evaluate and compare changes in axial elongation, over a 14-month period, in subjects who discontinued and then resumed ortho-k lens wear with those who continued to wear their lenses or spectacles following a 2-year myopia control study. This single masked, prospective study recruited subjects who had just completed a 2-year myopia control study. Ortho-k subjects were classified as Group OKc, in which subjects continued ortho-k lens wear for the duration of the study; or Group OKd in which subjects discontinued lens wear for seven months and wore single-vision spectacles (Phase I) and then resumed ortho-k lens wear for another seven months (Phase II). Spectacle-wearing control subjects from the initial myopia control study continued wearing spectacles as control subjects. Axial lengths were measured at scheduled visits using the IOLMaster. Thirteen, 16, and 15 Control, OKc, and OKd subjects, aged 8-14 years, respectively completed the study. Significant increase in axial elongation was found in OKd subjects only in Phase I but not in Phase II. On resuming lens wear, in Phase II, the rate of axial elongation was no longer significantly different from those of the Control or OKc subjects. Stopping ortho-k lens wear at or before the age of 14 years led to a more rapid increase in axial length; comparable to those wearing spectacles during the initial 2-year myopia control study, but greater than the Control and OKc group in this study. Axial elongation slowed again with resumed lens wear after six months. Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Construction of an ortholog database using the semantic web technology for integrative analysis of genomic data.

PubMed

Chiba, Hirokazu; Nishide, Hiroyo; Uchiyama, Ikuo

2015-01-01

Recently, various types of biological data, including genomic sequences, have been rapidly accumulating. To discover biological knowledge from such growing heterogeneous data, a flexible framework for data integration is necessary. Ortholog information is a central resource for interlinking corresponding genes among different organisms, and the Semantic Web provides a key technology for the flexible integration of heterogeneous data. We have constructed an ortholog database using the Semantic Web technology, aiming at the integration of numerous genomic data and various types of biological information. To formalize the structure of the ortholog information in the Semantic Web, we have constructed the Ortholog Ontology (OrthO). While the OrthO is a compact ontology for general use, it is designed to be extended to the description of database-specific concepts. On the basis of OrthO, we described the ortholog information from our Microbial Genome Database for Comparative Analysis (MBGD) in the form of Resource Description Framework (RDF) and made it available through the SPARQL endpoint, which accepts arbitrary queries specified by users. In this framework based on the OrthO, the biological data of different organisms can be integrated using the ortholog information as a hub. Besides, the ortholog information from different data sources can be compared with each other using the OrthO as a shared ontology. Here we show some examples demonstrating that the ortholog information described in RDF can be used to link various biological data such as taxonomy information and Gene Ontology. Thus, the ortholog database using the Semantic Web technology can contribute to biological knowledge discovery through integrative data analysis.

Quick and simple sample treatment for multiresidue analysis of bisphenols, bisphenol diglycidyl ethers and their derivatives in canned food prior to liquid chromatography and fluorescence detection.

PubMed

Alabi, A; Caballero-Casero, N; Rubio, S

2014-04-04

We report herein a multiresidue method for canned food determination of 12 bisphenols [bisphenol A (BPA), bisphenol B (BPB), bisphenol F (BPF), bisphenol E (BPE)], bisphenol diglycidyl ethers [bisphenol F diglycidyl ether (BFDGE), bisphenol A diglycidyl ether (BADGE)] and their derivatives [BADGE·2H2O, BADGE·H2O, BADGE·HCl·H2O, BADGE·HCl, BADGE·2HCl and BFDGE·2HCl]. The method was based on the microextraction of the target contaminants in 200mg food sample with 600 μL of a supramolecular solvent made up of inverse aggregates of tetradecanol, followed by analysis of the extract by liquid chromatography/fluorescence detection using external calibration. Chromatographic separation of all target compounds, including the ortho-ortho, ortho-para and para-para isomers of BFDGE and BFDGE·2HCl, was achieved with baseline separation (Resolution ≥ 1.52). No concentration of the extracts was required, the microextraction took about 30 min and several samples could be simultaneous treated. Method validation was carried out according to the recommendations of the European Commission Decision 2002/657/EC. Quantitation limits for the different analytes ranged between 0.9 and 3.5 μg kg(-1). Repeatability and reproducibility, expressed as relative standard deviation, were in the ranges 1.8-6.8% and 4.4-8.1%. The method was applied to the analysis of the target compounds in different food categories including vegetables, legumes, fruits, fish and seafood, meat product and grain. Recoveries in samples were within the range 80-110%. Only BPF and BPE were undetected in the canned food analyzed. The concentration found for the rest of bisphenols, diglycidyl ethers and derivatives was in the range 7.1-959 μg kg(-1). The study of the isomeric distribution of BFDGE and BFDGE·2HCl in food showed that they are preferentially present as one of the isomeric forms, that highlighting for further studies. The analytical and operational characteristics of this multiresidue method make it suitable for monitoring programs intended for the assessment of human exposure to bisphenols, diglycidyl ethers and derivatives from diet. Copyright © 2014 Elsevier B.V. All rights reserved.

Mechanical rigidity of the Ortho-SUV frame compared to the Ilizarov frame in the correction of femoral deformity.

PubMed

Skomoroshko, Petr V; Vilensky, Victor A; Hammouda, Ahmed I; Fletcher, Matt D A; Solomin, Leonid N

2015-04-01

The Ortho-SUV frame (OSF) is a novel hexapod circular external fixator which draws upon the innovation of the Ilizarov method and the advantages of hexapod construction in the three-dimensional control of bone segments. Stability of fixation is critical to the success or failure of an external circular fixator for fracture or osteotomy healing. In vitro biomechanical modelling study was performed comparing the stability of the OSF under load in both original form and after dynamisation to the Ilizarov fixator in all zones of the femur utilising optimal frame configuration. A superior performance of the OSF in terms of resistance to deforming forces in both original and dynamised forms over that of the original Ilizarov fixator was found. The OSF shows higher rigidity than the Ilizarov in the control of forces acting upon the femur. This suggests better stabilisation of femoral fractures and osteotomies and thus improved healing with a reduced incidence of instability-related bone segment deformity, non-union and delayed union.

High brilliant thermal and cold moderator for the HBS neutron source project Jülich

NASA Astrophysics Data System (ADS)

Cronert, T.; Dabruck, J. P.; Doege, P. E.; Bessler, Y.; Klaus, M.; Hofmann, M.; Zakalek, P.; Rücker, U.; Lange, C.; Butzek, M.; Hansen, W.; Nabbi, R.; Brückel, T.

2016-09-01

The proposed High Brilliance Neutron Source (HBS), recognized within the Helmholtz Association of German Research Centres, will optimize the entire chain from particle source through particle accelerator, target, moderator, reflector, shielding, beam extraction, beam transport all the way to the detector, utilizing the nuclear Be(p,n) or Be(d,n) reaction in the lower MeV energy range. A D2O moderating reflector prototype (MRP) and a cold source were constructed and build according to MCNP parameter studies. The MRP was tested in a feasibility study at the TREFF instrument at MLZ (Garching). Cold beam extraction from the flux maximum within the moderator based on liquid para H2 and other cold moderators will be tested by energy spectroscopy via TOF-method. Different ratios of liquid ortho/para H2 will be fed to the cold moderator. The ratio will be controlled by feeding from reservoires of natural liquid H2 and a storage loop with an ortho/para converter and determined via online heat capacity measurement.

Global variation of the para hydrogen fraction in Jupiter's atmosphere and implications for dynamics on the outer planets

NASA Technical Reports Server (NTRS)

Conrath, B. J.; Gierasch, P. J.

1984-01-01

A detailed analysis of the Voyager infrared spectrometer measurements on Jupiter's atmosphere is presented, and possible implications of para hydrogen disequilibrium for the energetics and dynamics of that atmosphere are examined. The method of data analysis is described, and results for the large scale latitude variation of the para hydrogen fraction are presented. The Jovian results show pronounced latitude variation, and are compared with other parameters including wind fields, thermal structure, and various indicators of atmospheric clouds. The problem of equilibration rate is reexamined, and it is concluded that on Jupiter the equilibration time is longer than the radiative time constant at the level of emission to space, but that this inequality reverses at greater depths. A model for the interaction of fluid motions with the ortho-para conversion process is presented, and a consistent mixing length theory for the reacting ortho-para mixture is developed. Several implications of the Jovian data for atmospheric energetics and stability on the outer planets are presented.

Isovanillin derived N-(un)substituted hydroxylamines possessing an ortho-allylic group: valuable precursors to bioactive N-heterocycles.

PubMed

Dulla, Balakrishna; Tangellamudi, Neelima D; Balasubramanian, Sridhar; Yellanki, Swapna; Medishetti, Raghavender; Kumar Banote, Rakesh; Hari Chaudhari, Girish; Kulkarni, Pushkar; Iqbal, Javed; Reiser, Oliver; Pal, Manojit

2014-04-28

The intramolecular 1,3-dipolar cycloaddition of isovanillin derived N-aryl hydroxylamines possessing ortho-allylic dipolarophiles affords novel benzo analogues of tricyclic isoxazolidines that can be readily transformed into functionalized lactams, γ-aminoalcohols and oxazepines. The corresponding N-unsubstituted hydroxylamines give rise to tetrahydroisoquinolines. Anxiogenic properties of these compounds are tested in zebra fish.

The Ortho-Syllable as a Processing Unit in Handwriting: The Mute E Effect

ERIC Educational Resources Information Center

Lambert, Eric; Sausset, Solen; Rigalleau, François

2015-01-01

Some research on written production has focused on the role of the syllable as a processing unit. However, the precise nature of this syllable unit has yet to be elucidated. The present study examined whether the nature of this processing unit is orthographic (i.e., an ortho-syllable) or phonological. We asked French adults to copy three-syllable…

Structure and sublimation of water ice films grown in vacuo at 120-190 K studied by positron and positronium annihilation.

PubMed

Townrow, S; Coleman, P G

2014-03-26

The crystalline structure of ∼ 5-20 μm water ice films grown at 165 and 172 K has been probed by measuring the fraction of positrons forming ortho-positronium (ortho-Ps) and decaying into three gamma photons. It has been established that films grown at slower rates (water vapour pressure ≥ 1 mPa) have lower concentrations of lattice defects and closed pores, which act as Ps traps, than those grown at higher rates (vapour pressure ∼ 100 mPa), evidenced by ortho-Ps diffusion lengths being approximately four times greater in the former. By varying the growth temperature between 162 and 182 K it was found that films become less disordered at temperatures above ∼ 172 K, with the ortho-Ps diffusion length rising by ∼ 60%, in this range. The sublimation energy for water ice films grown on copper has been measured to be 0.462(5) eV using the time dependence of positron annihilation parameters from 165 to 195 K, in agreement with earlier studies and with no measurable dependence on growth rate and thermal history.

OrthoANI: An improved algorithm and software for calculating average nucleotide identity.

PubMed

Lee, Imchang; Ouk Kim, Yeong; Park, Sang-Cheol; Chun, Jongsik

2016-02-01

Species demarcation in Bacteria and Archaea is mainly based on overall genome relatedness, which serves a framework for modern microbiology. Current practice for obtaining these measures between two strains is shifting from experimentally determined similarity obtained by DNA-DNA hybridization (DDH) to genome-sequence-based similarity. Average nucleotide identity (ANI) is a simple algorithm that mimics DDH. Like DDH, ANI values between two genome sequences may be different from each other when reciprocal calculations are compared. We compared 63 690 pairs of genome sequences and found that the differences in reciprocal ANI values are significantly high, exceeding 1 % in some cases. To resolve this problem of not being symmetrical, a new algorithm, named OrthoANI, was developed to accommodate the concept of orthology for which both genome sequences were fragmented and only orthologous fragment pairs taken into consideration for calculating nucleotide identities. OrthoANI is highly correlated with ANI (using BLASTn) and the former showed approximately 0.1 % higher values than the latter. In conclusion, OrthoANI provides a more robust and faster means of calculating average nucleotide identity for taxonomic purposes. The standalone software tools are freely available at http://www.ezbiocloud.net/sw/oat.

Observation of Ortho-Para Dependence of Pressure Broadening Coefficient in Acetylene νb{1}+νb{3} Vibration Band Using Dual-Comb Spectroscopy

NASA Astrophysics Data System (ADS)

Iwakuni, Kana; Okubo, Sho; Inaba, Hajime; Onae, Atsushi; Hong, Feng-Lei; Sasada, Hiroyuki; Yamada, Koichi MT

2016-06-01

We observe that the pressure-broadening coefficients depend on the ortho-para levels. The spectrum is taken with a dual-comb spectrometer which has the resolution of 48 MHz and the frequency accuracy of 8 digit when the signal-to-noise ratio is more than 20. In this study, about 4.4-Tz wide spectra of the P(31) to R(31) transitions in the νb{1}+νb{3} vibration band of 12C_2H_2 are observed at the pressure of 25, 60, 396, 1047, 1962 and 2654 Pa. Each rotation-vibration absorption line is fitted to Voight function and we determined pressure-broadening coefficients for each rotation-vibration transition. The Figure shows pressure broadening coefficient as a function of m. Here m is J"+1 for R and -J" for P-branch. The graph shows obvious dependence on ortho and para. We fit it to Pade function considering the population ratio of three-to-one for the ortho and para levels. This would lead to detailed understanding of the pressure boarding mechanism. S. Okubo et al., Applied Physics Express 8, 082402 (2015)

Investigation into the effects of stainless steel ligature ties on the mechanical characteristics of conventional and self-ligated brackets subjected to torque.

PubMed

Al Fakir, Hussam; Carey, Jason P; Melenka, Garrett W; Nobes, David S; Heo, Giseon; Major, Paul W

2014-09-01

Torque is applied to orthodontic brackets in order to alter the buccal-lingual angulation of a tooth. One factor that can affect torque is the ligation mode used to retain the archwire in the bracket slot. The objective of this study was to investigate the effects of stainless steel ligation on torque expression and bracket deformation. This study utilized 60 upper right central incisor Damon Q brackets and 60 Ormco Orthos Twin brackets. The brackets used in this study were subdivided into four groups: (1) Damon Q ligated with SS ligature; (2) Damon Q with the sliding bracket door; (3) Orthos Twin bracket ligated with SS wire; and (4) Orthos Twin ligated with elastic ties. All brackets were tested using an orthodontic torque simulating device that applied archwire rotation from 0° to 45°. All brackets ligated with stainless steel ties exhibited greater torque expression and less deformation than brackets without stainless steel ties. As well, Damon Q brackets exhibit less bracket deformation than Orthos Twin brackets. Stainless steel ties can reduce the amount of plastic deformation for both types of brackets used in this study. © 2014 British Orthodontic Society.

Infrared spectra of CO2-doped hydrogen clusters, (H2)N-CO2.

PubMed

McKellar, A R W

2012-03-07

Clusters of para-H(2) and/or ortho-H(2) containing a single carbon dioxide molecule are studied by high resolution infrared spectroscopy in the 2300 cm(-1) region of the CO(2) ν(3) fundamental band. The (H(2))(N)-CO(2) clusters are formed in a pulsed supersonic jet expansion from a cooled nozzle and probed using a rapid scan tunable diode laser. Simple symmetric rotor type spectra are observed with little or no resolved K-structure, and prominent Q-branch features for ortho-H(2) but not para-H(2). Observed rotational constants and vibrational shifts are reported for ortho-H(2) up to N = 7 and para-H(2) up to N = 15, with the N > 7 assignments only made possible with the help of theoretical simulations. The para-H(2) cluster with N = 12 shows clear evidence for superfluid effects, in good agreement with theory. The presence of larger clusters with N > 15 is evident in the spectra, but specific assignments are not possible. Mixed para- + ortho-H(2) cluster transitions are well predicted by linear interpolation between corresponding pure cluster line positions. © 2012 American Institute of Physics

Quantum effects of translational motions in solid para-hydrogen and ortho-deuterium: anharmonic extension of the Einstein model.

PubMed

Kühn, O; Manz, J; Schild, A

2010-04-07

An anharmonic extension of the Einstein model is developed in order to describe the effect of translational zero point motion on structural and thermodynamic properties of para-H(2) and ortho-D(2) crystals in the zero temperature limit. Accordingly, the molecules carry out large amplitude translational motions in their matrix cage, which are formed by the frozen environment of all other molecules. These translations lead from the molecular equilibrium positions via the harmonic to the anharmonic domain of the potential energy surface. The resulting translational distributions are roughly isotropic, and they have approximately Gaussian shapes, with rather broad full widths at half-maximum, FWHM(para-H(2)/ortho-D(2)) = 1.36/1.02 Å. The translational zero point energies induce expansions of the crystals, in nearly quantitative agreement with experimental results. Furthermore, they make significant contributions to the sublimation energies and zero pressure bulk moduli. These quantum effects decrease with heavier molecular masses. The corresponding isotope effects for ortho-D(2) compared to para-H(2) are confirmed by application of the model to Ar crystals. The results imply consequences for laser induced reaction dynamics of dopants with their host crystals.

Cluster size resolving analysis of CH3F-(ortho-H2)n in solid para-hydrogen using FTIR absorption spectroscopy at 3 μm region.

PubMed

Miyamoto, Yuki; Momose, Takamasa; Kanamori, Hideto

2012-11-21

Infrared absorption spectra of methyl fluoride with ortho-hydrogen (ortho-H(2)) clusters in a solid para-hydrogen (para-H(2)) crystal at 3.6 K were studied in the C-H stretching fundamental region (~3000 cm(-1)) using an FTIR spectrometer. As shown previously, the ν(3) C-F stretching fundamental band of CH(3)F-(ortho-H(2))(n) (n = 0, 1, 2, ...) clusters at 1040 cm(-1) shows a series of n discrete absorption lines, which correspond to different-sized clusters. We observed three unresolved broad peaks in the C-H stretching region and applied this cluster model to them assuming the same intensity distribution function as the ν(3) band. A fitting analysis successfully gave us the linewidth and lineshift of the components in each vibrational band. It was found that the separately determined linewidth, matrix shift of the band origin, and cluster shift are dependent on the vibrational mode. From the transition intensities of the monomer component derived from the fitting analysis, we discuss the mixing ratio of the vibrational modes due to Fermi resonance.

Contextual influences in texture-segmentation: distinct effects from elements along the edge and in the texture-region.

PubMed

Robol, Valentina; Grassi, Massimo; Casco, Clara

2013-08-09

Both neurophysiological and psychophysical evidence suggest a strong influence of context on texture-segmentation. Here we extend and further analyse this issue, with a particular focus on the underlying mechanism. Specifically, we use a texture-edge discrimination task and separately investigate the effect of elements far from and along the edge. Consistent with previous studies, we report both an iso-near contextual effect - whereby performance is better if elements along the edge are iso-oriented compared to ortho-oriented to the edge - as well as an ortho-far effect - whereby discrimination is higher when elements far from the edge are orthogonal to the edge. We found that backward mask, which is known to interrupt re-entrant processing from extrastriate areas, only interferes with the iso-near effect whereas perturbing orientation, position or contrast polarity of elements far from the edge only abolishes the ortho-far effect. This suggests that feedback processes may be involved in the iso-near effect. Instead, the ortho-far effect may be accounted for by recurrent interactions among 1st order filters. Copyright © 2013 Elsevier Ltd. All rights reserved.

Yangians and Yang-Baxter R-operators for ortho-symplectic superalgebras

NASA Astrophysics Data System (ADS)

Fuksa, J.; Isaev, A. P.; Karakhanyan, D.; Kirschner, R.

2017-04-01

Yang-Baxter relations symmetric with respect to the ortho-symplectic superalgebras are studied. We start with the formulation of graded algebras and the linear superspace carrying the vector (fundamental) representation of the ortho-symplectic supergroup. On this basis we study the analogy of the Yang-Baxter operators considered earlier for the cases of orthogonal and symplectic symmetries: the vector (fundamental) R-matrix, the L-operator defining the Yangian algebra and its first and second order evaluations. We investigate the condition for L (u) in the case of the truncated expansion in inverse powers of u and give examples of Lie algebra representations obeying these conditions. We construct the R-operator intertwining two superspinor representations and study the fusion of L-operators involving the tensor product of such representations.

Intramolecular Aza-Diels-Alder Reactions of ortho-Quinone Methide Imines: Rapid, Catalytic, and Enantioselective Assembly of Benzannulated Quinolizidines.

PubMed

Kretzschmar, Martin; Hofmann, Fabian; Moock, Daniel; Schneider, Christoph

2018-04-16

Aza-Diels-Alder reactions (ADARs) are powerful processes that furnish N-heterocycles in a straightforward fashion. Intramolecular variants offer the additional possibility of generating bi- and polycyclic systems with high stereoselectivity. We report herein a novel Brønsted acid catalyzed process in which ortho-quinone methide imines tethered to the dienophile via the N substituent react in an intramolecular ADAR to form complex quinolizidines and oxazinoquinolines in a one-step process. The reactions proceed under very mild conditions, with very good yields and good to very good diastereo- and enantioselectivities. Furthermore, the process was extended to a domino reaction that efficiently combines substrate synthesis, ortho-quinone methide imine formation, and ADAR. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quadratic response functions in the relativistic four-component Kohn-Sham approximation

NASA Astrophysics Data System (ADS)

Henriksson, Johan; Saue, Trond; Norman, Patrick

2008-01-01

A formulation and implementation of the quadratic response function in the adiabatic four-component Kohn-Sham approximation is presented. The noninteracting reference state is time-reversal symmetric and formed from Kramers pair spinors, and the energy density is gradient corrected. Example calculations are presented for the optical properties of disubstituted halobenzenes in their meta and ortho conformations. It is demonstrated that correlation and relativistic effects are not additive, and it is shown that relativity alone reduces the μβ¯-response signal by 62% and 75% for meta- and ortho-bromobenzene, respectively, and enhances the same response by 17% and 21% for meta- and ortho-iodobenzene, respectively. Of the employed functionals, CAM-B3LYP shows the best performance and gives hyperpolarizabilities β distinctly different from B3LYP.

Photoisomerization of Trans Ortho-, Meta-, Para-Nitro Diarylbutadienes: A Case of Regioselectivity.

PubMed

Agnihotri, Harsha; Paramasivam, Mahalingavelar; Palakollu, Veerabhadraiah; Kanvah, Sriram

2015-11-01

A series of ortho-, meta- and para-substituted trans-nitro aryl (phenyl and pyridyl) butadienes have been synthesized and characterized. The effect of substitution and positional selectivity on their fluorescence and photoisomerization were systematically investigated. Among all dienes, meta- and para-nitro phenyl-substituted derivatives exhibit remarkable solvatochromic emission shifts due to intramolecular charge transfer. On the other hand, ortho derivatives undergo regioselective isomerization upon photoexcitation in contrast to inefficient isomerization of para and meta nitro-substituted dienes. Single crystal X-ray analysis revealed existence of intramolecular hydrogen bonding between the nitro group and the hydrogen of the proximal double bond. This restricts the rotation of the proximal double bond thereby allowing regioselective isomerization. The observations were also supported by NMR spectroscopic studies. © 2015 The American Society of Photobiology.

Evidence for disequilibrium of ortho and para hydrogen on Jupiter from Voyager IRIS measurements

NASA Technical Reports Server (NTRS)

Conrath, B. J.; Gierasch, P. J.

1983-01-01

Preliminary results of an analysis of the ortho state/para state ratio (parallel/antiparallel) for molecular H2 in the Jovian atmosphere using Voyager IR spectrometer (IRIS) data are reported. The study was undertaken to expand the understanding of the thermodynamics of a predominantly H2 atmosphere, which takes about 100 million sec to reach equilibrium. IRIS data provided 4.3/cm resolution in the 300-700/cm spectral range dominated by H2 lines. Approximately 600 spectra were examined to detect any disequilibrium between the hydrogen species. The results indicate that the ortho-para ratio is not in an equilibrium state in the upper Jovian troposphere. A thorough mapping of the para-state molecules in the upper atmosphere could therefore aid in mapping the atmospheric flowfield.

Phosphorus losses from agricultural watersheds in the Mississippi Delta.

PubMed

Yuan, Yongping; Locke, Martin A; Bingner, Ronald L; Rebich, Richard A

2013-01-30

Phosphorus (P) loss from agricultural fields is of environmental concern because of its potential impact on water quality in streams and lakes. The Mississippi Delta has long been known for its fish productivity and recreational value, but high levels of P in fresh water can lead to algal blooms that have many detrimental effects on natural ecosystems. Algal blooms interfere with recreational and aesthetic water use. However, few studies have evaluated P losses from agricultural watersheds in the Mississippi Delta. To better understand the processes influencing P loss, rainfall, surface runoff, sediment, ortho-P (orthophosphate, PO(4)-P), and total P (TP) were measured (water years 1996-2000) for two subwatersheds (UL1 and UL2) of the Deep Hollow Lake Watershed and one subwatershed of the Beasley Lake Watershed (BL3) primarily in cotton production in the Mississippi Delta. Ortho-P concentrations ranged from 0.01 to 1.0 mg/L with a mean of 0.17 mg/L at UL1 (17.0 ha), 0.36 mg/L at UL2 (11.2 ha) and 0.12 mg/L at BL3 (7.2 ha). The TP concentrations ranged from 0.14 to 7.9 mg/L with a mean of 0.96 mg/L at UL1, 1.1 mg/L at UL2 and 1.29 mg/L at BL3. Among the three sites, UL1 and UL2 received P application in October 1998, and BL3 received P applications in the spring of 1998 and 1999. At UL1, ortho-P concentrations were 0.36, 0.25 and 0.16 for the first, second and third rainfall events after P application, respectively; At UL2, ortho-P concentrations were 1.0, 0.66 and 0.65 for the first, second and third rainfall events after P application, respectively; and at BL3, ortho-P concentrations were 0.11, 0.22 and 0.09 for the first, second and third rainfall events after P application, respectively. P fertilizer application did influence P losses, but high P concentrations observed in surface runoff were not always a direct result of P fertilizer application or high rainfall. Application of P in the fall (UL1 and UL2) resulted in more ortho-P losses, likely because high rainfall often occurred in the winter months soon after application. The mean ortho-P concentrations were higher at UL1 and UL2 than those at BL3, although BL3 received more P application during the monitoring period, because P was applied in spring at BL3. However, tillage associated with planting and incorporating applied P in the spring (BL3) may have resulted in more TP loss in sediment, thus the mean TP concentration was the highest at BL3. Ortho-P loss was correlated with surface runoff; and TP loss was correlated with sediment loss. These results indicate that applying P fertilizer in the spring may be recommended to reduce potential ortho-P loss during the fallow winter season; in addition, conservation practices may reduce potential TP loss associated with soil loss. Published by Elsevier Ltd.

Phosphorus losses from agricultural watersheds in the Mississippi Delta

USGS Publications Warehouse

Yuan, Yongping; Locke, Martin A.; Bingner, Ronald L.; Rebich, Richard A.

2013-01-01

Phosphorus (P) loss from agricultural fields is of environmental concern because of its potential impact on water quality in streams and lakes. The Mississippi Delta has long been known for its fish productivity and recreational value, but high levels of P in fresh water can lead to algal blooms that have many detrimental effects on natural ecosystems. Algal blooms interfere with recreational and aesthetic water use. However, few studies have evaluated P losses from agricultural watersheds in the Mississippi Delta. To better understand the processes influencing P loss, rainfall, surface runoff, sediment, ortho-P (orthophosphate, PO4–P), and total P (TP) were measured (water years 1996–2000) for two subwatersheds (UL1 and UL2) of the Deep Hollow Lake Watershed and one subwatershed of the Beasley Lake Watershed (BL3) primarily in cotton production in the Mississippi Delta. Ortho-P concentrations ranged from 0.01 to 1.0 mg/L with a mean of 0.17 mg/L at UL1 (17.0 ha), 0.36 mg/L at UL2 (11.2 ha) and 0.12 mg/L at BL3 (7.2 ha). The TP concentrations ranged from 0.14 to 7.9 mg/L with a mean of 0.96 mg/L at UL1, 1.1 mg/L at UL2 and 1.29 mg/L at BL3. Among the three sites, UL1 and UL2 received P application in October 1998, and BL3 received P applications in the spring of 1998 and 1999. At UL1, ortho-P concentrations were 0.36, 0.25 and 0.16 for the first, second and third rainfall events after P application, respectively; At UL2, ortho-P concentrations were 1.0, 0.66 and 0.65 for the first, second and third rainfall events after P application, respectively; and at BL3, ortho-P concentrations were 0.11, 0.22 and 0.09 for the first, second and third rainfall events after P application, respectively. P fertilizer application did influence P losses, but high P concentrations observed in surface runoff were not always a direct result of P fertilizer application or high rainfall. Application of P in the fall (UL1 and UL2) resulted in more ortho-P losses, likely because high rainfall often occurred in the winter months soon after application. The mean ortho-P concentrations were higher at UL1 and UL2 than those at BL3, although BL3 received more P application during the monitoring period, because P was applied in spring at BL3. However, tillage associated with planting and incorporating applied P in the spring (BL3) may have resulted in more TP loss in sediment, thus the mean TP concentration was the highest at BL3. Ortho-P loss was correlated with surface runoff; and TP loss was correlated with sediment loss. These results indicate that applying P fertilizer in the spring may be recommended to reduce potential ortho-P loss during the fallow winter season; in addition, conservation practices may reduce potential TP loss associated with soil loss.

Erythrocyte Alloimmunization and Autoimmunization among Blood Donors and Recipients visiting a Tertiary Care Hospital.

PubMed

Kaur, Daljit; Bains, Lovenish; Kandwal, Manoj; Parmar, Indu

2017-03-01

The ultimate aim of pretransfusion testing is the acceptable survival of donor red cells in recipient's body and antibody detection plays a critical role in achieving the same. The cornerstone of antibody detection method is detecting an unexpected antibody as against the expected antibodies of ABO blood group system. Autoantibodies can also interfere with the detection of clinically significant alloantibodies. To study the frequency of alloantibodies and autoantibodies in the healthy blood donors and patient population visiting our hospital. The Column Agglutination Technology (CAT) was used for ABO RhD blood grouping, Direct Antiglobulin Test (DAT), Autocontrol (AC), Indirect Antiglobulin Test (IAT) and red cell antibody screening and the unexpected reactions in any of these tests were recorded for further evaluation. Ethylene Diamine Tetra Acetic Acid (EDTA) blood samples were used for all these tests for both blood donors and admitted patients. The CAT was exercised for the blood grouping (using ABD-Reverse Diluent cassettes) and antibody screening (using 0.8% Surgiscreen, Ortho Clinical Diagnostics Limited, USA and Low Ionic Strength Saline Ortho BLISS with AHG cassettes) on the automated immunohaematology platform ORTHO AutoVue ® Innova system (Ortho Clinical Diagnostics Limited, USA). Among all blood donors (n=6350), seven (0.11%) donors had showed unexpected reaction. Of these, four had positive antibody screen (three having naturally occuring antibodies 2=anti-M, 1=anti-Le a and 1=inconclusive) and the other three had positive DAT. Of all the patient samples (n=6136) screened for irregular red cell antibodies, four (0.06%) patients were found to have unexpected reaction revealing one (0.02%) with anti-M antibody and the other three (0.05%) had autoantibodies in their serum. The combined prevalence for both blood donor and recipient population (n=12,486) was found to be 0.11% at our center. The alloimmunisation among patient population was found to be lower than many other studies worldwide as our hospital does not cater to multitransfused or transfusion dependant patients with haematological disorders and majorly elective surgery patients with no history of previous blood transfusions visit our hospital.

Effects of orthokeratology on the progression of low to moderate myopia in Chinese children.

PubMed

He, Mengmei; Du, Yaru; Liu, Qingyu; Ren, Chengda; Liu, Junling; Wang, Qianyi; Li, Li; Yu, Jing

2016-07-27

To investigate the effectiveness of orthokeratology (ortho-k) in reducing the development of myopia in Chinese children with low to moderate myopia. This was a retrospective study. In the ortho-k group, there were141 subjects, and the average age was (9.43 ± 1.10) years. The average spherical equivalent refractive error (SER) was (-2.74 ± 1.15)D, with examinations performed 1, 7, 30, and 90 days and 12 months after the patients started wearing ortho-k lenses. In the control group, there were 130 subjects, and the average age was (9.37 ± 1.00) years. The average SER was (-2.88 ± 1.39)D, with examinations performed every 6 months. Axial elongation, which is an important parameter reflecting the progression of myopia, was measured at baseline from the same IOLMaster each time by the same masked examiner and was compared between the groups after 1 year. The subjects were divided into two sub-groups according to age to further study the development of myopia at different ages. An unpaired t-test, paired t-test, Chi-square test and Spearman test were performed to analyze the data. After 1 year, the average axial elongation was (0.27 ± 0.17) mm in the ortho-k lens group and (0.38 ± 0.13) mm in the control group, with a significant difference between the groups (P < 0.001). Axial elongation was not correlated with SER but had a negative correlation with initial age (ortho-k group: r s = -0.309, p < 0.01; control group: r s = -0.472, p < 0.01). The percentages of individuals with fast myopic progression (axial elongation > 0.36 mm per year) were 38.0 % among younger children (7.00 to 9.40 years) and 24.3 % among older children (9.40 to 12.00 years), whereas the respective percentages were 76.5 and 12.9 % in the control group. When SER ranged from -5.0D to -6.0D, the axial elongation in the ortho-k group was 57.1 % slower than that in the control group. Ortho-k lenses are effective in controlling myopic progression in Chinese children, particularly in younger children and in children with higher myopia.

OrthoSelect: a protocol for selecting orthologous groups in phylogenomics.

PubMed

Schreiber, Fabian; Pick, Kerstin; Erpenbeck, Dirk; Wörheide, Gert; Morgenstern, Burkhard

2009-07-16

Phylogenetic studies using expressed sequence tags (EST) are becoming a standard approach to answer evolutionary questions. Such studies are usually based on large sets of newly generated, unannotated, and error-prone EST sequences from different species. A first crucial step in EST-based phylogeny reconstruction is to identify groups of orthologous sequences. From these data sets, appropriate target genes are selected, and redundant sequences are eliminated to obtain suitable sequence sets as input data for tree-reconstruction software. Generating such data sets manually can be very time consuming. Thus, software tools are needed that carry out these steps automatically. We developed a flexible and user-friendly software pipeline, running on desktop machines or computer clusters, that constructs data sets for phylogenomic analyses. It automatically searches assembled EST sequences against databases of orthologous groups (OG), assigns ESTs to these predefined OGs, translates the sequences into proteins, eliminates redundant sequences assigned to the same OG, creates multiple sequence alignments of identified orthologous sequences and offers the possibility to further process this alignment in a last step by excluding potentially homoplastic sites and selecting sufficiently conserved parts. Our software pipeline can be used as it is, but it can also be adapted by integrating additional external programs. This makes the pipeline useful for non-bioinformaticians as well as to bioinformatic experts. The software pipeline is especially designed for ESTs, but it can also handle protein sequences. OrthoSelect is a tool that produces orthologous gene alignments from assembled ESTs. Our tests show that OrthoSelect detects orthologs in EST libraries with high accuracy. In the absence of a gold standard for orthology prediction, we compared predictions by OrthoSelect to a manually created and published phylogenomic data set. Our tool was not only able to rebuild the data set with a specificity of 98%, but it detected four percent more orthologous sequences. Furthermore, the results OrthoSelect produces are in absolut agreement with the results of other programs, but our tool offers a significant speedup and additional functionality, e.g. handling of ESTs, computing sequence alignments, and refining them. To our knowledge, there is currently no fully automated and freely available tool for this purpose. Thus, OrthoSelect is a valuable tool for researchers in the field of phylogenomics who deal with large quantities of EST sequences. OrthoSelect is written in Perl and runs on Linux/Mac OS X. The tool can be downloaded at (http://gobics.de/fabian/orthoselect.php).

Pressure-induced orientational glass phase in molecular para-hydrogen.

PubMed

Schelkacheva, T I; Tareyeva, E E; Chtchelkatchev, N M

2009-02-01

We propose a theoretical description of a possible orientational glass transition in solid molecular para-hydrogen and ortho-deuterium under pressure supposing that they are mixtures of J=0 and J=2 states of molecules. The theory uses the basic concepts and methods of standard spin-glass theory. We expect our orientational glass to correspond to the II' phase of the high-pressure hydrogen phase diagram.

ORTHO-LBNP: A new apparatus for assessing autocontrol mechanisms of the heart-vessel system in pilots undergoing training in conditions of ischemic hypoxia and orthostatic stress

NASA Astrophysics Data System (ADS)

Truszczynski, Olaf; Skibniewski, Franciszek; Dziuda, Lukasz; Gacek, Adam; Krej, Mariusz; Sobotnicki, Aleksander; Rajchel, Jan; Bylinka, Marek; Burek, Michal

The authors present a new system for examining the behaviour of the human body and cerebral circulation in conditions of ischemic hypoxia and orthostatic stress that can cause orthostatic hypotension. Ischemic hypoxia affects mainly pilots of highly manoeuvrable aircraft, where long-lasting G forces not seldom reach 6-8 +Gz and can exceed the gravitational acceleration by ten times or more. Additionally, pilots are subjected to orthostatic hypotension in which abnormally low blood pressure is caused by pressure adjustment disorder and decreased stroke volume when changing body position rapidly. For several decades, these effects have been deeply investigated using human centrifuges or lower body negative pressure (LBNP) chambers. The latter method involves significantly less financial resources to carry out experiments and training, whereas the effects exerted on pilots, and the results of the training can be comparable. A group of researchers from the Military Institute of Aviation Medicine, Warszawa, Poland, and the Institute of Medical Technology and Equipment ITAM, Zabrze, Poland, are developing the innovative ORTHO-LBNP device based on the cradle principle and the LBNP method. The system will be implemented in a modern programme for training cadets of the Polish Air Force Academy, Dęblin, Poland. Together with other equipment such as a high-G centrifuge, pressure chambers, flight and spatial disorientation simulators as well as gymnastic training equipment for pilots (GTEP), the ORTHO-LBNP apparatus will be an element of the selection system of candidates for aviation. It is expected that the experimental studies will result in developing new indicators providing an objective assessment, whether examined persons possess the traits necessary for performing tasks related to the job of a pilot. It is highly probable that those indicators can be incorporated into routine checks for pilots, which in turn, can lead to improving the safety of flight operations and to higher fighting efficiency in pilots.

Photosensitization by iodinated DNA minor groove binding ligands: Evaluation of DNA double-strand break induction and repair.

PubMed

Briggs, Benjamin; Ververis, Katherine; Rodd, Annabelle L; Foong, Laura J L; Silva, Fernando M Da; Karagiannis, Tom C

2011-05-03

Iodinated DNA minor groove binding bibenzimidazoles represent a unique class of UVA photosensitizer and their extreme photopotency has been previously characterized. Earlier studies have included a comparison of three isomers, referred to as ortho-, meta- and para-iodoHoechst, which differ only in the location of the iodine substituent in the phenyl ring of the bibenzimidazole. DNA breakage and clonogenic survival studies in human erythroleukemic K562 cells have highlighted the higher photo-efficiency of the ortho-isomer (subsequently designated UV(A)Sens) compared to the meta- and para-isomers. In this study, the aim was to compare the induction and repair of DNA double-strand breaks induced by the three isomers in K562 cells. Further, we examined the effects of the prototypical broad-spectrum histone deacetylase inhibitor, Trichostatin A, on ortho-iodoHoechst/UVA-induced double-strand breaks in K562 cells. Using γH2AX as a molecular marker of the DNA lesions, our findings indicate a disparity in the induction and particularly, in the repair kinetics of double-strand breaks for the three isomers. The accumulation of γH2AX foci induced by the meta- and para-isomers returned to background levels within 24 and 48 h, respectively; the number of γH2AX foci induced by ortho-iodoHoechst remained elevated even after incubation for 96 h post-irradiation. These findings provide further evidence that the extreme photopotency of ortho-iodoHoechst is due to not only to the high quantum yield of dehalogenation, but also to the severity of the DNA lesions which are not readily repaired. Finally, our findings which indicate that Trichostatin A has a remarkable potentiating effect on ortho-iodoHoechst/UVA-induced DNA lesions are encouraging, particularly in the context of cutaneous T-cell lymphoma, for which a histone deacetylase inhibitor is already approved for therapy. This finding prompts further evaluation of the potential of combination therapies. Copyright © 2011 Elsevier B.V. All rights reserved.

Increasing the Analytical Sensitivity by Oligonucleotides Modified with Para- and Ortho-Twisted Intercalating Nucleic Acids – TINA

PubMed Central

Schneider, Uffe V.; Géci, Imrich; Jøhnk, Nina; Mikkelsen, Nikolaj D.; Pedersen, Erik B.; Lisby, Gorm

2011-01-01

The sensitivity and specificity of clinical diagnostic assays using DNA hybridization techniques are limited by the dissociation of double-stranded DNA (dsDNA) antiparallel duplex helices. This situation can be improved by addition of DNA stabilizing molecules such as nucleic acid intercalators. Here, we report the synthesis of a novel ortho-Twisted Intercalating Nucleic Acid (TINA) amidite utilizing the phosphoramidite approach, and examine the stabilizing effect of ortho- and para-TINA molecules in antiparallel DNA duplex formation. In a thermal stability assay, ortho- and para-TINA molecules increased the melting point (Tm) of Watson-Crick based antiparallel DNA duplexes. The increase in Tm was greatest when the intercalators were placed at the 5′ and 3′ termini (preferable) or, if placed internally, for each half or whole helix turn. Terminally positioned TINA molecules improved analytical sensitivity in a DNA hybridization capture assay targeting the Escherichia coli rrs gene. The corresponding sequence from the Pseudomonas aeruginosa rrs gene was used as cross-reactivity control. At 150 mM ionic strength, analytical sensitivity was improved 27-fold by addition of ortho-TINA molecules and 7-fold by addition of para-TINA molecules (versus the unmodified DNA oligonucleotide), with a 4-fold increase retained at 1 M ionic strength. Both intercalators sustained the discrimination of mismatches in the dsDNA (indicated by ΔTm), unless placed directly adjacent to the mismatch – in which case they partly concealed ΔTm (most pronounced for para-TINA molecules). We anticipate that the presented rules for placement of TINA molecules will be broadly applicable in hybridization capture assays and target amplification systems. PMID:21673988

Luminescence properties of Sm3+-doped alkaline earth ortho-stannates

NASA Astrophysics Data System (ADS)

Stanulis, Andrius; Katelnikovas, Artūras; Enseling, David; Dutczak, Danuta; Šakirzanovas, Simas; Bael, Marlies Van; Hardy, An; Kareiva, Aivaras; Jüstel, Thomas

2014-05-01

A series of Sm3+ doped M2SnO4 (M = Ca, Sr and Ba) samples were prepared by a conventional high temperature solid-state reaction route. All samples were characterized by powder X-ray diffraction (XRD) analysis, photoluminescence (PL), photoluminescence thermal quenching (TQ) and fluorescence lifetime (FL) measurements. The morphology of synthesized phosphor powders was examined by scanning electron microscopy (SEM). Moreover, luminous efficacies (LE) and color points of the CIE 1931 color space diagram were calculated and discussed. Synthesized powders showed bright orange-red emission under UV excitation. Based on the results obtained we demonstrate that Sm3+ ions occupy Ca and Sr sites in the Ca2SnO4 and Sr2SnO4 ortho-stannate structures, respectively. In contrast, Sm3+ substitutes Sn in the barium ortho-stannate Ba2SnO4 structure.

Hyperfine excitation of C2H in collisions with ortho- and para-H2

NASA Astrophysics Data System (ADS)

Dagdigian, Paul J.

2018-06-01

Accurate estimation of the abundance of the ethynyl (C2H) radical requires accurate radiative and collisional rate coefficients. Hyperfine-resolved rate coefficients for (de-)excitation of C2H in collisions with ortho- and para-H2 are presented in this work. These rate coefficients were computed in time-independent close-coupling quantum scattering calculations that employed a potential energy surface recently computed at the coupled-clusters level of theory that describes the interaction of C2H with H2. Rate coefficients for temperatures from 10 to 300 K were computed for all transitions among the first 40 hyperfine energy levels of C2H in collisions with ortho- and para-H2. These rate coefficients were employed in simple radiative transfer calculations to simulate the excitation of C2H in typical molecular clouds.

An antibacterial ortho-quinone diterpenoid and its derivatives from Caryopteris mongolica.

PubMed

Saruul, Erdenebileg; Murata, Toshihiro; Selenge, Erdenechimeg; Sasaki, Kenroh; Yoshizaki, Fumihiko; Batkhuu, Javzan

2015-06-15

To identify antibacterial components in traditional Mongolian medicinal plant Caryopteris mongolica, an ortho-quinone abietane caryopteron A (1) and three its derivatives caryopteron B-D (2-4) were isolated from the roots of the plant together with three known abietanes demethylcryptojaponol (5), 6α-hydroxydemethyl cryptojaponol (6), and 14-deoxycoleon U (7). The chemical structures of these abietane derivatives were elucidated on the basis of spectroscopic data. Compounds 1-4 had C-13 methylcyclopropane substructures, and 2-4 had a hexanedioic anhydride ring C instead of ortho-quinone in 1. The stereochemistry of these compound was assumed from NOE spectra and ECD Cotton effects. Compounds 1 and 5-7 showed antibacterial activities against the Gram-positive bacteria Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, and Micrococcus luteus, being 1 the more potent. Copyright © 2015 Elsevier Ltd. All rights reserved.

orthoFind Facilitates the Discovery of Homologous and Orthologous Proteins.

PubMed

Mier, Pablo; Andrade-Navarro, Miguel A; Pérez-Pulido, Antonio J

2015-01-01

Finding homologous and orthologous protein sequences is often the first step in evolutionary studies, annotation projects, and experiments of functional complementation. Despite all currently available computational tools, there is a requirement for easy-to-use tools that provide functional information. Here, a new web application called orthoFind is presented, which allows a quick search for homologous and orthologous proteins given one or more query sequences, allowing a recurrent and exhaustive search against reference proteomes, and being able to include user databases. It addresses the protein multidomain problem, searching for homologs with the same domain architecture, and gives a simple functional analysis of the results to help in the annotation process. orthoFind is easy to use and has been proven to provide accurate results with different datasets. Availability: http://www.bioinfocabd.upo.es/orthofind/.

H2CS abundances and ortho-to-para ratios in interstellar clouds

NASA Technical Reports Server (NTRS)

Minh, Y. C.; Irvine, W. M.; Brewer, M. K.

1991-01-01

Several H2CS ortho and para transitions have been observed toward interstellar molecular clouds, including cold, dark clouds and star-forming regions. H2CS fractional abundances f(H2CS) about 1-2 10 to the -9th relative to molecular hydrogen toward TMC-1, Orion A, and NGC 7538, and about 5 10 to the -10th for L134N are derived. The H2CS ortho-to-para ratios in TMC-1 are about 1.8 toward the cyanopolyyne peak and the ammonia peak, which may indicate the thermalization of H2CS on 10 K grains. A ratio of about 3, the statistical value, for Orion (3N, 1E) and NGC 7538 is derived, while a value of about 2 for Orion (KL) is found.

Separating para and ortho water.

PubMed

Horke, Daniel A; Chang, Yuan-Pin; Długołęcki, Karol; Küpper, Jochen

2014-10-27

Water exists as two nuclear-spin isomers, para and ortho, determined by the overall spin of its two hydrogen nuclei. For isolated water molecules, the conversion between these isomers is forbidden and they act as different molecular species. Yet, these species are not readily separated, and no pure para sample has been produced. Accordingly, little is known about their specific physical and chemical properties, conversion mechanisms, or interactions. The production of isolated samples of both spin isomers is demonstrated in pure beams of para and ortho water in their respective absolute ground state. These single-quantum-state samples are ideal targets for unraveling spin-conversion mechanisms, for precision spectroscopy and fundamental symmetry-breaking studies, and for spin-enhanced applications, for example laboratory astrophysics and astrochemistry or hypersensitized NMR experiments. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Conversion of para and ortho hydrogen in the Jovian planets

NASA Technical Reports Server (NTRS)

Massie, S. T.; Hunten, D. M.

1982-01-01

A mechanism is proposed which partially equilibrates the para and ortho rotational levels of molecular hydrogen in the atmospheres of Jupiter, Saturn, and Uranus. Catalytic reactions between the free-radical surface sites of aerosol particles and hydrogen modecules yield significant equilibration near 1 bar pressure, if the efficiency of conversion per collision is between 10 to the -8th and 10 to the -10th and the effective eddy mixing coefficient is 10,000 sq cm/sec. At lower pressures the ortho-para ratio retains the value at the top of the cloud layer, except for a very small effect from conversion in the thermosphere. The influence of conversion on the specific heat and adiabatic lapse rate is also investigated. The effect is found to be generally small, though is can rise to 10% inside the aerosol layer.

Dielectric property of NiTiO{sub 3} doped substituted ortho-chloropolyaniline composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lakshmi, Mohana; Faisal, Muhammad; Roy, Aashish S.

2013-11-15

Ortho-chloropolyaniline (OCP)-NiTiO{sub 3} composites have been synthesized via in-situ polymerization of ortho-chloroaniline with various weight percentages of NiTiO{sub 3.} Fourier Transform Infrared spectroscopic studies of Ortho-chloropolyaniline and its composites indicated the formation of composites as a result of Vander Waal's interaction between OCP and NiTiO{sub 3} particles. Surface morphology of OCP and OCP-NiTiO{sub 3} composites were studied using Scanning Electron Microscope (SEM). The SEM micrographs indicated a modified morphology after the composite formation. Dielectric properties and electric modulus of OCP and OCP-NiTiO{sub 3} composites have been investigated in the frequency range of 50 Hz – 5 MHz. It has beenmore » noticed that electrical resistance decreases with increase in weight percentage of NiTiO{sub 3} particles in polymer matrix as well as with applied frequency. The display of semicircular arcs in Cole-Cole plots indicates the formation of series resistor and capacitor in network causing a decrease in the relaxation time and as a result conductivity enhances in these composites. The facile and cost effective synthesis process and excellent dielectric and conductivity response of these materials makes them promising materials for practical applications.« less

Dielectric property of NiTiO{sub 3} doped substituted ortho-chloropolyaniline composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lakshmi, Mohana; Faisal, Muhammad; Roy, Aashish S.

Ortho-chloropolyaniline (OCP)-NiTiO{sub 3} composites have been synthesized via in-situ polymerization of ortho-chloroaniline with various weight percentages of NiTiO{sub 3.} Fourier Transform Infrared spectroscopic studies of Ortho-chloropolyaniline and its composites indicated the formation of composites as a result of Vander Waal's interaction between OCP and NiTiO{sub 3} particles. Surface morphology of OCP and OCP-NiTiO{sub 3} composites were studied using Scanning Electron Microscope (SEM). The SEM micrographs indicated a modified morphology after the composite formation. Dielectric properties and electric modulus of OCP and OCP-NiTiO{sub 3} composites have been investigated in the frequency range of 50 Hz – 5 MHz. It has beenmore » noticed that electrical resistance decreases with increase in weight percentage of NiTiO{sub 3} particles in polymer matrix as well as with applied frequency. The display of semicircular arcs in Cole-Cole plots indicates the formation of series resistor and capacitor in network causing a decrease in the relaxation time and as a result conductivity enhances in these composites. The facile and cost effective synthesis process and excellent dielectric and conductivity response of these materials makes them promising materials for practical applications.« less

High resolution quantum cascade laser studies of the ν3 band of methyl fluoride in solid para-hydrogen.

PubMed

McKellar, A R W; Mizoguchi, Asao; Kanamori, Hideto

2011-09-28

Spectra of solid para-H(2) doped with CH(3)F at 1.8 K are studied in the ν(3) region (~1040 cm(-1)) using a quantum cascade laser source. As shown previously, residual ortho-H(2) in the sample (~1000 ppm) gives rise to distinct spectral features due to clusters of the form CH(3)F-(ortho-H(2))(N), with N = 0, 1, 2, 3, etc. Brief annealing at 7 K is found to give narrower spectral lines (≥0.006 cm(-1)) than conventional (5 K) annealing, and causes the N = 3 and 4 lines to fragment into two or more components. The N = 3 line is observed to be particularly stable and persistent. The N = 0 line (no ortho-H(2) neighbors) is resolved into two closely spaced (≈0.007 cm(-1)) components which are assigned to the K = 0 and 1 states of CH(3)F rotating around its C(3v) symmetry axis (ortho- and para-CH(3)F, respectively). Similar K-structure is also evident for other lines. Weak but persistent features ("N = 1/2 lines") are observed mid way between N = 0 and 1. © 2011 American Institute of Physics

ortho- and meta-substituted aromatic thiols are efficient redox buffers that increase the folding rate of a disulfide-containing protein.

PubMed

Gough, Jonathan D; Barrett, Elvis J; Silva, Yenia; Lees, Watson J

2006-08-20

Thiol based redox buffers are used to enhance the folding rates of disulfide-containing proteins in vitro. Traditionally, small molecule aliphatic thiols such as glutathione are employed. Recently, we have demonstrated that aromatic thiols can further enhance protein-folding rates. In the presence of para-substituted aromatic thiols the folding rate of a disulfide-containing protein was increased by 4-23 times over that measured for glutathione. However, several important practical issues remain to be addressed. Aromatic thiols have never been tested in the presence of denaturants such as guanidine hydrochloride. Only two of the para-substituted aromatic thiols previously examined are commercially available. To expand the number of aromatic thiols for protein folding, several commercially available meta- and ortho-substituted aromatic thiols were studied. Furthermore, an ortho-substituted aromatic thiol, easily obtained from inexpensive starting materials, was investigated. Folding rates of scrambled ribonuclease A at pH 6.0, 7.0 and 7.7, with ortho- and meta-substituted aromatic thiols, were up to 10 times greater than those with glutathione. In the presence of the common denaturant guanidine hydrochloride (0.5M) aromatic thiols provided 100% yield of active protein while maintaining equivalent folding rates.

An effective and low cost carbon based clean-up method for PCDD/Fs and PCBs analysis in food.

PubMed

Kedikoglou, Kleopatra; Costopoulou, Danae; Vassiliadou, Irene; Bakeas, Evangelos; Leondiadis, Leondios

2018-09-01

Sample preparation is of critical importance in dioxin analysis of food and feed samples. It is a complex procedure that includes lipid extraction followed by the application of chromatographic separation techniques, aiming in removing undesirable interferences from the matrix. The separation of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from polychlorinated biphenyls (PCBs) is achieved by carbon-based materials which should have high fat capacity in order to be suitable for lipid-containing matrices. Automated methods are available but due to high cost and use of high amounts of solvents, manual methods are also applied. An active carbon material (Carbosphere) with high fat capacity that has been used in the past for manual methods is no longer commercially available. The present study assesses an alternative active carbon material, FU 4652, that can be used for the separation of PCDD/Fs and non-ortho PCBs. Mono-ortho and 6 non-dioxin-like PCBs are also analyzed. The method was validated according to the analytical criteria set in EU regulations 589/2014 and 709/2014. Control samples analyzed for the evaluation of the above material were olive oil reference samples spiked with PCDD/Fs and dioxin-like PCBs at two concentration levels. The new method was tested successfully on food samples of interlaboratory trials organized in previous years. Farmed fish samples collected within national surveillance programs for the years 2016-2017 were analyzed with the method developed. The results obtained indicate that the FU 4652 carbon sorbent has high fat capacity and is capable of separating congeners with good recoveries. Copyright © 2018 Elsevier Ltd. All rights reserved.

Analysis of cocaine and metabolites in hair: validation and application of measurement of hydroxycocaine metabolites as evidence of cocaine ingestion.

PubMed

Schaffer, Michael; Cheng, Chen-Chih; Chao, Oscar; Hill, Virginia; Matsui, Paul

2016-03-01

An LC/MS/MS method to identify and quantitate in hair the minor metabolites of cocaine-meta-, para-, and ortho-hydroxy cocaine-was developed and validated. Analysis was performed on a triple quadrupole ABSciex API 3000 MS equipped with an atmospheric pressure ionization source via an IonSpray (ESI). For LC, a series 200 micro binary pump with a Perkin Elmer Model 200 autosampler was used. The limit of detection (LOD) and limit of quantification (LOQ) were 0.02 ng/10 mg hair, with linearity from 0.02 to 10 ng/10 mg hair. Concentrations of the para isomer in extensively washed hair samples were in the range of 1-2 % of the cocaine in the sample, while the concentrations of the ortho form were considerably less. The method was used to analyze large numbers of samples from two populations: workplace and criminal justice. In vitro experiments to determine if deodorants or peroxide-containing cosmetic treatments could result in the presence of these metabolites in hair showed that this does not occur with extensively washed hair. Presence of hydroxycocaines, when detected after aggressive washing of the hair samples, provides a valuable additional indicator of ingestion of cocaine rather than mere environmental exposure.

Ortho-H2 and the age of prestellar cores

NASA Astrophysics Data System (ADS)

Pagani, L.; Lesaffre, P.; Jorfi, M.; Honvault, P.; González-Lezana, T.; Faure, A.

2013-03-01

Prestellar cores form from the contraction of cold gas and dust material in dark clouds before they collapse to form protostars. Several concurrent theories exist to describe this contraction but they are currently difficult to distinguish. One major difference is the timescale involved in forming the prestellar cores: some theories advocate nearly free-fall speed via, e.g., rapid turbulence decay, while others can accommodate much longer periods to let the gas accumulate via, e.g., ambipolar diffusion. To tell the difference between these theories, measuring the age of prestellar cores could greatly help. However, no reliable clock currently exists. We present a simple chemical clock based on the regulation of the deuteration by the abundance of ortho-H2 that slowly decays away from the ortho-para statistical ratio of 3 down to or less than 0.001. We use a chemical network fully coupled to a hydrodynamical model that follows the contraction of a cloud, starting from uniform density, and reaches a density profile typical of a prestellar core. We compute the N2D+/N2H+ ratio along the density profile. The disappearance of ortho-H2 is tied to the duration of the contraction and the N2D+/N2H+ ratio increases in the wake of the ortho-H2 abundance decrease. By adjusting the time of contraction, we obtain different deuteration profiles that we can compare to the observations. Our model can test fast contractions (from 104 to 106 cm-3 in ~0.5 My) and slow contractions (from 104 to 106 cm-3 in ~5 My). We have tested the sensitivity of the models to various initial conditions. The slow-contraction deuteration profile is approximately insensitive to these variations, while the fast-contraction deuteration profile shows significant variations. We found that, in all cases, the deuteration profile remains clearly distinguishable whether it comes from the fast collapse or the slow collapse. We also study the para-D2H+/ortho-H2D+ ratio and find that its variation is not monotonic, so it does not discriminate between models. Applying this model to L183 (=L134N), we find that the N2D+/N2H+ ratio would be higher than unity for evolutionary timescales of a few megayears independently of other parameters, such as cosmic ray ionization rate or grain size (within reasonable ranges). A good fit to the observations is only obtained for fast contraction (≤0.7 My from the beginning of the contraction and ≤4 My from the birth of the molecular cloud based on the need to keep a high ortho-H2 abundance when the contraction starts - ortho-H2/para-H2 ≥ 0.2 - to match the observations). This chemical clock therefore rules out slow contraction in L183 and steady-state chemical models, since steady state is clearly not reached here. This clock should be applied to other cores to help distinguish slow and fast contraction theories over a large sample of cases. Appendices are available in electronic form at http://www.aanda.org

Copper-Catalyzed, Directing Group-Assisted Fluorination of Arene and Heteroarene C-H Bonds

PubMed Central

Truong, Thanh; Klimovica, Kristine; Daugulis, Olafs

2013-01-01

We have developed a method for direct, copper-catalyzed, auxiliary-assisted fluorination of β-sp2 C-H bonds of benzoic acid derivatives and γ-sp2 C-H bonds of α,α-disubstituted benzylamine derivatives. The reaction employs CuI catalyst, AgF fluoride source, and DMF, pyridine, or DMPU solvent at moderately elevated temperatures. Selective mono- or difluorination can be achieved by simply changing reaction conditions. The method shows excellent functional group tolerance and provides a straightforward way for the preparation of ortho-fluorinated benzoic acids. PMID:23758609

Diversity-oriented synthesis of dihydrobenzoxazepinones by coupling the Ugi multicomponent reaction with a Mitsunobu cyclization

PubMed Central

Moni, Lisa; Banfi, Luca; Basso, Andrea; Brambilla, Alice

2014-01-01

Summary An operationally simple protocol for the synthesis of 2,3-dihydrobenzo[f][1,4]oxazepin-3-ones, based on an Ugi reaction of an ortho-(benzyloxy)benzylamine, glycolic acid, an isocyanide and an aldehyde, followed by an intramolecular Mitsunobu substitution was developed. The required ortho-(benzyloxy)benzylamines have been in situ generated from the corresponding azides, in turn prepared in high yields from salicylic derivatives. PMID:24605140

[Pd(μ-Cl)Cl(IPr*)]2: a highly hindered pre-catalyst for the synthesis of tetra-ortho-substituted biaryls via Grignard reagent cross-coupling.

PubMed

Lesieur, Mathieu; Slawin, Alexandra M Z; Cazin, Catherine S J

2014-08-14

The new well-defined catalyst [Pd(μ-Cl)Cl(IPr*)]2 enables the efficient Grignard reagent cross-coupling for the synthesis of tetra-ortho-substituted biaryls. The high reactivity of the complex is associated with the important bulkiness of the IPr* ligand. The dimer represents the most efficient catalyst reported to date for this challenging transformation.

Laboratory Graduate Fellowship Program, 1989. Appendix D, Part 1. Certifications and Concurrence

DTIC Science & Technology

1989-01-01

takes place in nitric acid/sulfuric acid at degrees C for 3 hours. Nitration occurs both ortho and para the acetanilide (NHAc) moiety. This was...unexpected as acetanilide is usually a strong para director. Currently we preparing bulkier diamides using isobutyric anhydride and trimethylacetic...C for 3 hours. Nitration occurs both ortho and para t the acetanilide (NHAc) moiety. This was unexpected as acetanilide is usually a strong para

Rotational state modification and fast ortho-para conversion of H2 trapped within the highly anisotropic potential of Pd(210)

NASA Astrophysics Data System (ADS)

Ohno, S.; Ivanov, D.; Ogura, S.; Wilde, M.; Arguelles, E. F.; Diño, W. A.; Kasai, H.; Fukutani, K.

2018-02-01

The rotational state and ortho-para conversion of H2 on a Pd(210) surface is investigated with rotational-state-selective temperature-programmed desorption (RS-TPD) and theoretical calculations. The isotope dependence of TPD shows a higher desorption energy for D2 than that for H2, which is ascribed to the rotational and zero-point vibrational energies. The RS-TPD data show that the desorption energy of H2(J =1 ) (J : rotational quantum number) is higher than that of H2(J =0 ). This is due to the orientationally anisotropic potential confining the adsorbed H2, which is in agreement with theoretical calculations. Furthermore, the H2 desorption intensity ratio in J =1 and J =0 indicates fast ortho-para conversion in the adsorption state, which we estimate to be of the order of 1 s.

ortho-Substituted (Aryl)(3-nitrobenzo[b]thiophen-2-yl)amines: Study of the Electrochemical Behavior

NASA Astrophysics Data System (ADS)

Cosimelli, Barbara; Lanza, Camilla Zaira; Scavetta, Erika; Severi, Elda; Spinelli, Domenico; Stenta, Marco; Tonelli, Domenica

2009-08-01

The reduction potentials of the title compounds 4 have been measured by cyclic voltammetry. The effect of the substituents has been evaluated by using a linear free energy relationship treatment, thus evidencing that the present ortho-substituents affect the Epc values basically by electronic effects. A comparison with data previously collected on ortho-substituted (aryl)(2-nitrobenzo[b]thiophen-3-yl)amines 3 has provided some interesting information. Different electrochemical behaviors are observed during the reduction (a reversible process and an irreversible process are operating in 3 and 4, respectively): to elucidate the reasons for this different behavior, the "reversible" reduction potentials of 5 and of 6 have been measured. Moreover, higher susceptibility constants have been calculated for compounds of series 4 with respect to those of series 3 (ρ4 = 329 and ρ3 = 182, respectively). A rationale for all of these findings has been offered.

Multistep divergent synthesis of benzimidazole linked benzoxazole/benzothiazole via copper catalyzed domino annulation.

PubMed

Liao, Jen-Yu; Selvaraju, Manikandan; Chen, Chih-Hau; Sun, Chung-Ming

2013-04-21

An efficient, facile synthesis of structurally diverse benzimidazole integrated benzoxazole and benzothiazoles has been developed. In a multi-step synthetic sequence, 4-fluoro-3-nitrobenzoic acid was converted into benzimidazole bis-heterocycles, via the intermediacy of benzimidazole linked ortho-chloro amines. The amphiphilic reactivity of this intermediate was designed to achieve the title compounds by the reaction of various acid chlorides and isothiocyanates in a single step through the in situ formation of ortho-chloro anilides and thioureas under microwave irradiation. A versatile one pot domino annulation reaction was developed to involve the reaction of benzimidazole linked ortho-chloro amines with acid chlorides and isothiocyanates. The initial acylation and urea formation followed by copper catalyzed intramolecular C-O and C-S cross coupling reactions furnished the angularly oriented bis-heterocycles which bear a close resemblance to the streptomyces antibiotic UK-1.

Hydroamination reactions of alkynes with ortho-substituted anilines in ball mills: synthesis of benzannulated N-heterocycles by a cascade reaction.

PubMed

Weiße, Maik; Zille, Markus; Jacob, Katharina; Schmidt, Robert; Stolle, Achim

2015-04-20

It was demonstrated that ortho-substituted anilines are prone to undergo hydroamination reactions with diethyl acetylenedicarboxylate in a planetary ball mill. A sequential coupling of the intermolecular hydroamination reaction with intramolecular ring closure was utilized for the syntheses of benzooxazines, quinoxalines, and benzothiazines from readily available building blocks, that is, electrophilic alkynes and anilines with OH, NH, or SH groups in the ortho position. For the heterocycle formation, it was shown that several stress conditions were able to initiate the reaction in the solid state. Processing in a ball mill seemed to be advantageous over comminution with mortar and pestle with respect to process control. In the latter case, significant postreaction modification occurred during solid-state analysis. Cryogenic milling proved to have an adverse effect on the molecular transformation of the reagents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A DFT study of permanganate oxidation of toluene and its ortho-nitroderivatives.

PubMed

Adamczyk, Paweł; Wijker, Reto S; Hofstetter, Thomas B; Paneth, Piotr

2014-02-01

Calculations of alternative oxidation pathways of toluene and its ortho-substituted nitro derivatives by permanganate anion have been performed. The competition between methyl group and ring oxidation has been addressed. Acceptable results have been obtained using IEFPCM/B3LYP/6-31+G(d,p) calculations with zero-point (ZPC) and thermal corrections, as validated by comparison with the experimental data. It has been shown that ring oxidation reactions proceed via relatively early transition states that become quite unsymmetrical for reactions involving ortho-nitrosubstituted derivatives. Transition states for the hydrogen atom abstraction reactions, on the other hand, are late. All favored reactions are characterized by the Gibbs free energy of activation, ΔG(≠), of about 25 kcal mol(-1). Methyl group oxidations are exothermic by about 20 kcal mol(-1) while ring oxidations are around thermoneutrality.

Ortho-para transition rate in mu-molecular hydrogen and the proton's induced pseudoscalar coupling gp.

PubMed

Clark, J H D; Armstrong, D S; Gorringe, T P; Hasinoff, M D; King, P M; Stocki, T J; Tripathi, S; Wright, D H; Zolnierczuk, P A

2006-02-24

We report a measurement of the ortho-para transition rate in the p mu p molecule. The experiment was conducted at TRIUMF via the measurement of the time dependence of the 5.2 MeV neutrons from muon capture in liquid hydrogen. The measurement yielded an ortho-para rate Lambda op = (11.1 +/- 1.7 +/-(0.9)(0.6)) x 10(4) s(-1), which is substantially larger than the earlier result of Bardin et al. The result has striking implications for the proton's induced pseudoscalar coupling g(p), changing the value of g(p) obtained from the most precise ordinary muon capture measurement from 10.6 +/- 2.7 to 0.8 +/- 2.8, and from the sole radiative muon capture measurement from 12.2 +/- 1.1 to 10.6 +/- 1.2, bringing the latter result closer to theoretical predictions.

Probes for narcotic receptor mediated phenomena. 42. Synthesis and in vitro pharmacological characterization of the N-methyl and N-phenethyl analogues of the racemic ortho-c and para-c oxide-bridged phenylmorphans

PubMed Central

Kim, Jin-Hee; Deschamps, Jeffrey R.; Rothman, Richard B.; Dersch, Christina M.; Folk, John E.; Cheng, Kejun; Jacobson, Arthur E.; Rice, Kenner C.

2011-01-01

A new synthesis of N-methyl and N-phenethyl substituted ortho-c and para-c oxide-bridged phenylmorphans, using N-benzyl- rather than N-methyl-substituted intermediates, was used and the pharmacological properties of these compounds were determined. The N-phenethyl substituted ortho-c oxide-bridged phenylmorphan (rac-(3R,6aS,11aS)-2-phenethyl-2,3,4,5,6,11a-hexahydro-1H-3,6a-methanobenzofuro[2,3-c]azocin-10-ol (12)) was found to have the highest μ-opioid receptor affinity (Ki = 1.1 nM) of all of the a- through f-oxide-bridged phenylmorphans. Functional data ([35S]GTP-γ-S) showed that the racemate 12 was more than three times more potent than naloxone as an μ-opioid antagonist. PMID:21570305

Spectral characteristics of ortho, meta and para dihydroxy benzenes in different solvents, pH and beta-cyclodextrin.

PubMed

Stalin, T; Devi, R Anitha; Rajendiran, N

2005-09-01

Spectral characteristics of ortho, meta and para dihydroxy benzenes (DHB's) have been studied in different solvents, pH and beta-cyclodextrin. Solvent study shows that: (i) the interaction of OH group with the aromatic ring is less than that of amino group both in the ground and excited states, (ii) in absorption, the charge transfer interaction of OH group in para position is larger than ortho and meta positions. pH studies reveals that DHB's are more acidic than phenol. The higher pK(a) value of oDHB (monoanion-dianion) indicates that the formed monoanion is more stabilized by intramolecular hydrogen bonding. DHB's forms a 1:1 inclusion complex with beta-CD. In beta-CD medium, absorption spectra of DHB's mono and dianions shows unusual blue shifts, whereas in the excited state, the spectral characteristics of DHB's follow the same trend in both aqueous and beta-CD medium.

Palladium-Catalyzed, N-(2-Aminophenyl)acetamide-Assisted Ortho-Arylation of Substituted Benzamides: Application to the Synthesis of Urolithins B, M6, and M7.

PubMed

Reddy, M Damoder; Blanton, Alexandra N; Watkins, E Blake

2017-05-19

Pd-catalyzed, selective, monoarylation of ortho-C-H bonds of various benzamides with aryl/heteroaryl iodides has been realized using N-(2-aminophenyl)acetamide (APA) as a new bidentate directing group for the first time. The reaction was tolerant of a wide range of functional groups, and a variety of biaryl amide derivatives were successfully prepared in good to moderate yield. The utilization of N-(2-aminophenyl)acetamide as a novel directing group, Mn(OAc) 2 as a co-oxidant (silver free reaction conditions), and absolute ortho-monoaryl selectivity are notable features of this reaction. In addition, the obtained monoarylated products could be further transformed into the bioactive natural products and human microflora metabolites of dietary ellagic acid derivatives, urolithin B, urolithin M6, and urolithin M7.

Core Perylene Diimide Designs via Direct Bay- and ortho-(Poly)trifluoromethylation: Synthesis, Isolation, X-Ray Structures, Optical and Electronic Properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clikeman, Tyler T.; Bukovsky, Eric V.; Wang, Xue-Bin

2015-09-22

We developed an efficient solvent- and catalyst-free direct polytrifluoromethylation of solid perylene-3,4,9,10-tetracarboxylic dianhydride that produced a new family of (poly)perfluoroalkyl bay- and ortho-substituted PDIs with two different imide substituents. Direct hydrogen substitution with CN group led to the synthesis of a cyanated perfluoroalkyl PDI derivative for the first time. Absorption, steady-state and time-resolved emission, X-ray diffraction, electrochemical, and gas-phase electron affinity data allowed for systematic studies of substitution effects at bay, ortho, and imide positions in the new PDIs. Solid-state packing showed remarkable variations in the intermolecular interactions that are important for charge transport and photophysical properties. Moreover, analysis ofmore » the electrochemical data for 143 electron poor PDIs, including newly reported compounds, revealed some general trends and peculiar effects from substituting electron-withdrawing groups at all three positions.« less

Core Perylene Diimide Designs via Direct Bay and Ortho (Poly)trifluoromethylation: Synthesis, Isolation, X-ray Structures, Optical and Electronic Properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clikeman, Tyler T.; Bukovsky, Eric V.; Wang, Xue B.

2015-09-22

We developed an efficient solvent- and catalyst-free direct polytrifluoromethylation of solid perylene-3,4,9,10-tetracarboxylic dianhydride that produced a new family of (poly)perfluoroalkyl bay and ortho substituted PDIs with two different imide substituents. Direct hydrogen substitution with CN group led to the synthesis of a cyanated perfluoroalkyl PDI derivative for the first time. Absorption, steady-state and time-resolved emission, X-ray diffraction, electrochemical, and gas-phase electron affinity data allowed for systematic studies of substitution effects at bay, ortho, and imide positions in the new PDIs. Solid-state packing showed remarkable variations in the intermolecular interactions that are important for charge transport and photophysical properties. Analysis ofmore » the electrochemical data for 143 electron poor PDIs, including newly reported compounds, revealed some general trends and peculiar effects of electron withdrawing group substitution at all three positions.« less

Executive functions and aphasia treatment outcomes: data from an ortho-phonological cueing therapy for anomia in Chinese.

PubMed

Yeung, Olivia; Law, Sam-Po

2010-12-01

This study examined the existence of a possible relationship between anomic treatment outcomes and executive functions. An ortho-phonological cueing method was used to facilitate object naming in 12 Cantonese-speaking anomic individuals. Treatment effectiveness for each participant was quantified and correlated with the performance of executive functions and language tasks. It was found that 10 participants showed significant improvement in naming treated items. Eight of the participants were able to maintain treatment gains for at least 1 month. Phonological generalization effects were observed in two participants. Performance on the Test of Nonverbal Intelligence (TONI-3) was significantly correlated with effect sizes of treatment, treatment generalization and maintenance and the Attention Network Test (ANT) was significantly correlated with phonological generalization. The result of a simultaneous multiple regression suggested that the performance of the ANT played an important role in phonological generalization. The findings reinforce the current view about the role of executive functions in language rehabilitation. They also shed light on the effect of inhibitory control on treatment generalization.

Characterization of commercial iron chelates and their behavior in an alkaline and calcareous soil.

PubMed

Cantera, Rodrigo G; Zamarreño, Angel M; García-Mina, José M

2002-12-18

Iron deficiency is a common problem for many plants grown in alkaline and calcareous soils. To correct this problem, iron is supplied to plants as chelates. Several iron chelates are sold under diverse trademarks with different characteristics. This work evaluated 18 commercial products containing the most representative chelated iron sources used in agricultural practice in Spain when the study was done, namely the ferric chelates of EDDHA, EDDHMA, EDDCHA, EDDHSA, EDTA, and DTPA. The chelates were comprehensively characterized and quantitated by several techniques, including several chromatographic methods. Iron and chelate dynamics in soil were also studied in a model alkaline and calcareous soil. Results indicate that, in this model soil, among the different iron compounds studied only FeEDDHA and analogues have the capacity to maintain soluble iron in soil solution over time. These results are in agreement with general experience under field conditions. Furthermore, among the different ortho-ortho isomers of FeEDDHA's, FeEDDHSA and FeEDDCHA showed greater capacity than FeEDDHA and FeEDDHMA to maintain the chelated iron in soil solution over time.

Assessment of POPs in air from Spain using passive sampling from 2008 to 2015. Part II: Spatial and temporal observations of PCDD/Fs and dl-PCBs.

PubMed

Muñoz-Arnanz, Juan; Roscales, Jose L; Vicente, Alba; Ros, María; Barrios, Laura; Morales, Laura; Abad, Esteban; Jiménez, Begoña

2018-09-01

Time series (2008-2015) of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in ambient air from the Spanish Monitoring Program were analyzed. A total of 321 samples were collected seasonally each year in 5 urban and 7 background sites by means of passive air sampling. Air concentrations were higher at urban than background sites (urban vs. background concentration ranges): PCDD/Fs (26.9-1010 vs. 20.0-357 fg/m 3 ), non-ortho PCBs (0.113-3.14 vs. 0.042-2.00 pg/m 3 ) and mono-ortho PCBs (0.644-41.3 vs. 0.500-32.8 pg/m 3 ). Results showed significant decreases from 2009 for non-ortho PCBs and PCDD/Fs as well as for WHO 2006 -TEQs. These declines were sharper, and sometimes only significant, in urban places resulting in converging levels at urban and background sites for these pollutants at the end of the study period. In contrast, mono-ortho PCBs did not show any significant variation but a steady flat temporal behavior in their concentrations, suggesting the existence of different sources between mono-ortho and non-ortho PCBs. Seasonality was observed for air burdens of all these POPs. PCDD/Fs were mostly measured at higher concentrations in colder than in hot seasons, and the opposite was true for dl-PCBs. Seasonal variations for PCDD/Fs appeared to be related to changes in their sources (e.g. domestic heating, open burning) rather than to temperature per se. In contrast, environmental temperature dependent factors (e.g. increased partitioning into the gas phase) drove seasonal variations in dl-PCBs instead of seasonal changes in their sources. Regarding spatial patterns, significant greater levels of PCDD/Fs and dl-PCBs were generally found in cities compared to background areas, pointing out the role of densely populated areas as sources for these pollutants in Spain. As proven by our results, long-term monitoring activities are essential to assess and understand temporal behaviors for these POPs, as well as to evaluate the achievement of Stockholm Convention objectives. Copyright © 2018 Elsevier B.V. All rights reserved.

Exceptional sensitivity of metal-aryl bond energies to ortho-fluorine substituents: influence of the metal, the coordination sphere, and the spectator ligands on M-C/H-C bond energy correlations.

PubMed

Clot, Eric; Mégret, Claire; Eisenstein, Odile; Perutz, Robin N

2009-06-10

DFT calculations are reported of the energetics of C-H oxidative addition of benzene and fluorinated benzenes, Ar(F)H (Ar(F) = C(6)F(n)H(5-n), n = 0-5) at ZrCp(2) (Cp = eta(5)-C(5)H(5)), TaCp(2)H, TaCp(2)Cl, WCp(2), ReCp(CO)(2), ReCp(CO)(PH(3)), ReCp(PH(3))(2), RhCp(PH(3)), RhCp(CO), IrCp(PH(3)), IrCp(CO), Ni(H(2)PCH(2)CH(2)PH(2)), Pt(H(2)PCH(2)CH(2)PH(2)). The change in M-C bond energy of the products fits a linear function of the number of fluorine substituents, with different coefficients corresponding to ortho-, meta-, and para-fluorine. The values of the ortho-coefficient range from 20 to 32 kJ mol(-1), greatly exceeding the values for the meta- and para-coefficients (2.0-4.5 kJ mol(-1)). Similarly, the H-C bond energies of Ar(F)H yield ortho- and para-coefficients of 10.4 and 3.4 kJ mol(-1), respectively, and a negligible meta-coefficient. These results indicate a large increase in the M-C bond energy with ortho-fluorine substitution on the aryl ring. Plots of D(M-C) vs D(H-C) yield slopes R(M-C/H-C) that vary from 1.93 to 3.05 with metal fragment, all in excess of values of 1.1-1.3 reported with other hydrocarbyl groups. Replacement of PH(3) by CO decreases R(M-C/H-C) significantly. For a given ligand set and metals in the same group of the periodic table, the value of R(M-C/H-C) does not increase with the strength of the M-C bond. Calculations of the charge on the aryl ring show that variations in ionicity of the M-C bonds correlate with variations in M-C bond energy. This strengthening of metal-aryl bonds accounts for numerous experimental results that indicate a preference for ortho-fluorine substituents.

Ligand-Enabled meta-C–H Activation Using a Transient Mediator

PubMed Central

Wang, Xiao-Chen; Gong, Wei; Fang, Li-Zhen; Zhu, Ru-Yi; Li, Suhua; Engle, Keary M.; Yu, Jin-Quan

2015-01-01

Achieving site selectivity in C–H functionalization reactions is a significant challenge, especially when the target C–H bond is distant from existing functional groups.1–5 Coordination of a functional group to a metal catalyst is often a key driving force and control element in many important reactions including asymmetric hydrogenation,6 epoxidation7, 8, and lithiation9. Exploitation of this effect has led to the development of a broad range of directed C–H activation reactions.10–14 However, such C–H activation methods are limited to proximal C–H bonds, which are spatially and geometrically accessible from the directing functional group. Development of meta-selective C–H functionalizations remains a significant challenge.1–5,15–17 We recently developed a U- shaped template that can be used to overcome this constraint and have shown that it can be used to selectively activate remote meta-C–H bonds.1, 2 While this approach has proven applicable for a diverse set of substrates and catalytic transformations,3–5 the need for a covalently attached complex template is a significant drawback for synthetic applications. In this manuscript, we report an alternative approach, one that employs norbornene as a transient mediator to achieve meta-selective C–H activation with a simple and common ortho-directing group. The use of a newly developed pyridine-based ligand is crucial for relaying the palladium catalyst to the meta position by norbornene following initial ortho- C–H activation. Thus, this catalytic reaction demonstrates the feasibility of switching ortho-selectivity to meta-selectivity in C–H activation of the same substrate by catalyst control. PMID:25754328

ORTHO-TO-PARA ABUNDANCE RATIO OF WATER ION IN COMET C/2001 Q4 (NEAT): IMPLICATION FOR ORTHO-TO-PARA ABUNDANCE RATIO OF WATER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shinnaka, Yoshiharu; Kawakita, Hideyo; Kobayashi, Hitomi

2012-04-20

The ortho-to-para abundance ratio (OPR) of cometary molecules is considered to be one of the primordial characteristics of cometary ices, and contains information concerning their formation. Water is the most abundant species in cometary ices, and OPRs of water in comets have been determined from infrared spectroscopic observations of H{sub 2}O rovibrational transitions so far. In this paper, we present a new method to derive OPR of water in comets from the high-dispersion spectrum of the rovibronic emission of H{sub 2}O{sup +} in the optical wavelength region. The rovibronic emission lines of H{sub 2}O{sup +} are sometimes contaminated by othermore » molecular emission lines but they are not affected seriously by telluric absorption compared with near-infrared observations. Since H{sub 2}O{sup +} ions are mainly produced from H{sub 2}O by photoionization in the coma, the OPR of H{sub 2}O{sup +} is considered to be equal to that of water based on the nuclear spin conservation through the reaction. We have developed a fluorescence excitation model of H{sub 2}O{sup +} and applied it to the spectrum of comet C/2001 Q4 (NEAT). The derived OPR of water is 2.54{sup +0.32}{sub -0.25}, which corresponds to a nuclear spin temperature (T{sub spin}) of 30{sup +10}{sub -4} K. This is consistent with the previous value determined in the near-infrared for the same comet (OPR = 2.6 {+-} 0.3, T{sub spin} = 31{sup +11}{sub -5} K).« less

Structure-activity relationship of ortho- and meta-phenol based LFA-1 ICAM inhibitors.

PubMed

Lin, Edward Yin-Shiang; Guckian, Kevin M; Silvian, Laura; Chin, Donovan; Boriack-Sjodin, P Ann; van Vlijmen, Herman; Friedman, Jessica E; Scott, Daniel M

2008-10-01

LFA-1 ICAM inhibitors based on ortho- and meta-phenol templates were designed and synthesized by Mitsunobu chemistry. The selection of targets was guided by X-ray co-crystal data, and led to compounds which showed an up to 30-fold increase in potency over reference compound 1 in the LFA-1/ICAM1-Ig assay. The most active compound exploited a new hydrogen bond to the I-domain and exhibited subnanomolar potency.

Correlation Of Ortho-Positronium Intensity With Doppler Broadening For Rubber Above And Below The Glass Transition Temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Towry, Amanda; Quarles, C. A.

Previous research has demonstrated a correlation between the Doppler broadening S parameter and the intensity of the ortho-positronium lifetime component in polymers that depends on the composition of the polymer. On the other hand, rubber polymers do not show this correlation and behave more like liquids for which the S parameter is essentially independent of the ortho-positronium intensity. The bubble model has been suggested as an explanation of the lack of correlation in analogy with liquids, but the bubble model applied to rubber is controversial. There are two important differences between the rubber and the polymers samples: first, the rubbermore » samples at room temperature were all above the glass transition temperature (T{sub G}). Second, the rubber samples all contained sulfur and were vulcanized. These differences were investigated by first measuring the S parameter for six rubber samples below T{sub G} where the bubble model would not be expected to work. Second, raw rubber samples that did not contain any sulfur and were unvulcanized were studied at room temperature. The results show that the lack of correlation between the S parameter and the ortho-positronium intensity previously observed for vulcanized rubber is due to the inhibition of positronium formation by the sulfur in the vulcanized rubber samples rather than to the rubber being above T{sub G}.« less

OrthoDB v8: update of the hierarchical catalog of orthologs and the underlying free software.

PubMed

Kriventseva, Evgenia V; Tegenfeldt, Fredrik; Petty, Tom J; Waterhouse, Robert M; Simão, Felipe A; Pozdnyakov, Igor A; Ioannidis, Panagiotis; Zdobnov, Evgeny M

2015-01-01

Orthology, refining the concept of homology, is the cornerstone of evolutionary comparative studies. With the ever-increasing availability of genomic data, inference of orthology has become instrumental for generating hypotheses about gene functions crucial to many studies. This update of the OrthoDB hierarchical catalog of orthologs (http://www.orthodb.org) covers 3027 complete genomes, including the most comprehensive set of 87 arthropods, 61 vertebrates, 227 fungi and 2627 bacteria (sampling the most complete and representative genomes from over 11,000 available). In addition to the most extensive integration of functional annotations from UniProt, InterPro, GO, OMIM, model organism phenotypes and COG functional categories, OrthoDB uniquely provides evolutionary annotations including rates of ortholog sequence divergence, copy-number profiles, sibling groups and gene architectures. We re-designed the entirety of the OrthoDB website from the underlying technology to the user interface, enabling the user to specify species of interest and to select the relevant orthology level by the NCBI taxonomy. The text searches allow use of complex logic with various identifiers of genes, proteins, domains, ontologies or annotation keywords and phrases. Gene copy-number profiles can also be queried. This release comes with the freely available underlying ortholog clustering pipeline (http://www.orthodb.org/software). © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Optimization of large-volume injection for the determination of polychlorinated biphenyls in children's fast-food menus by low-resolution mass spectrometry.

PubMed

Esteve-Turrillas, Francesc A; Caupos, Emilie; Llorca, Isabel; Pastor, Agustín; de la Guardia, Miguel

2008-03-26

This study includes the determination of five indicator polychlorinated biphenyls (PCBs) (52, 101, 153, 138, and 180), six non-ortho PCBs (35, 80, 81, 77, 126, and 169), and two mono-ortho PCBs (28 and 118) in fast food for children. A freeze-dried sample of 10 g is extracted by using pressurized n-hexane in two 5 min cycles at 120 degrees C and 100 mbar. Fatty extracts were cleaned up by means of acetonitrile/n-hexane partitioning and gel-permeation chromatography. The fractionation of non-ortho, mono-ortho, and indicator PCBs was made on graphitized carbon solid-phase extraction cartridges by using n-hexane, n-hexane/toluene (99:1, v/v), and toluene as elution solvents. Gas chromatography coupled to tandem mass spectrometry and large-volume injections with a programmed-temperature vaporizer (PTV-LV) were used to increase sensitivity and selectivity of the PCB determination. The PTV-LV injection settings, that is, vaporizing temperature, vaporizing time, and purge flow, were optimized by using a central composite design. A 15-40 times increased sensitivity was reached as compared with that obtained with the conventional 1 microL splitless injection. The limits of detection achieved were between 0.3 and 1.2 pg/g, and repeatability data, as relative standard deviation varied, ranged from 2 to 9% for the 0.05 ng/mL PCB level.

Infrared spectra of N2O-(ortho-D2)N and N2O-(HD)N clusters trapped in bulk solid parahydrogen.

PubMed

Lorenz, Britney D; Anderson, David T

2007-05-14

High-resolution infrared spectra of the clusters N2O-(ortho-D2)N and N2O-(HD)N, N=1-4, isolated in bulk solid parahydrogen at liquid helium temperatures are studied in the 2225 cm-1 region of the nu3 antisymmetric stretch of N2O. The clusters form during vapor deposition of separate gas streams of a precooled hydrogen mixture (ortho-D2para-H2 or HDpara-H2) and N2O onto a BaF2 optical substrate held at approximately 2.5 K in a sample-in-vacuum liquid helium cryostat. The cluster spectra reveal the N2O nu3 vibrational frequency shifts to higher energy as a function of N, and the shifts are larger for ortho-D2 compared to HD. These vibrational shifts result from the reduced translational zero-point energy for N2O solvated by the heavier hydrogen isotopomers. These spectra allow the N=0 peak at 2221.634 cm-1, corresponding to the nu3 vibrational frequency of N2O isolated in pure solid parahydrogen, to be assigned. The intensity of the N=0 absorption feature displays a strong temperature dependence, suggesting that significant structural changes occur in the parahydrogen solvation environment of N2O in the 1.8-4.9 K temperature range studied.

An Artificial Tendon with Durable Muscle Interface

PubMed Central

Melvin, Alan; Litsky, Alan; Mayerson, Joel; Witte, David; Melvin, David; Juncosa-Melvin, Natalia

2010-01-01

A coupling mechanism that can permanently fix a forcefully contracting muscle to a bone anchor or any totally inert prosthesis would meet a serious need in orthopaedics. Our group developed the OrthoCoupler™ device to satisfy these demands. The objective of this study was to test OrthoCoupler’s performance in vitro and in vivo in the goat semitendinosus tendon model. For in vitro evaluation, 40 samples were fatigue-tested, cycling at 10 load levels, n=4 each. For in vivo evaluation, the semitendinosus tendon was removed bilaterally in 8 goats. Left sides were reattached with an OrthoCoupler, and right sides were reattached using the Krackow stitch with #5 braided polyester sutures. Specimens were harvested 60 days post-surgery and assigned for biomechanics and histology. Fatigue strength of the devices in vitro was several times the contractile force of the semitendinosus muscle. The in vivo devices were built equivalent to two of the in vitro devices, providing an additional safety factor. In strength testing at necropsy, suture controls pulled out at 120.5 ± 68.3 N, whereas each OrthoCoupler was still holding after the muscle tore, remotely, at 298±111.3N (mean ± SD)(p<0.0003). Muscle tear strength was reached with the fiber-muscle composite produced in healing still soundly intact. This technology may be of value for orthopaedic challenges in oncology, revision arthroplasty, tendon transfer, and sports-injury reconstruction. PMID:19639642

Theoretical study of the hydrogen abstraction of substituted phenols by nitrogen dioxide as a source of HONO.

PubMed

Shenghur, Abraham; Weber, Kevin H; Nguyen, Nhan D; Sontising, Watit; Tao, Fu-Ming

2014-11-20

The mild yet promiscuous reactions of nitrogen dioxide (NO2) and phenolic derivatives to produce nitrous acid (HONO) have been explored with density functional theory calculations. The reaction is found to occur via four distinct pathways with both proton coupled electron transfer (PCET) and hydrogen atom transfer (HAT) mechanisms available. While the parent reaction with phenol may not be significant in the gas phase, electron donating groups in the ortho and para positions facilitate the reduction of nitrogen dioxide by electronically stabilizing the product phenoxy radical. Hydrogen bonding groups in the ortho position may additionally stabilize the nascent resonantly stabilized radical product, thus enhancing the reaction. Catechol (ortho-hydroxy phenol) has a predicted overall free energy change ΔG(0) = -0.8 kcal mol(-1) and electronic activation energy Ea = 7.0 kcal mol(-1). Free amines at the ortho and para positions have ΔG(0) = -3.8 and -1.5 kcal mol(-1); Ea = 2.3 and 2.1 kcal mol(-1), respectively. The results indicate that the hydrogen abstraction reactions of these substituted phenols by NO2 are fast and spontaneous. Hammett constants produce a linear correlation with bond dissociation energy (BDE) demonstrating that the BDE is the main parameter controlling the dark abstraction reaction. The implications for atmospheric chemistry and ground-level nitrous acid production are discussed.

H2 Ortho-to-para Conversion on Grains: A Route to Fast Deuterium Fractionation in Dense Cloud Cores?

NASA Astrophysics Data System (ADS)

Bovino, S.; Grassi, T.; Schleicher, D. R. G.; Caselli, P.

2017-11-01

Deuterium fractionation, I.e., the enhancement of deuterated species with respect to non-deuterated ones, is considered to be a reliable chemical clock of star-forming regions. This process is strongly affected by the ortho-to-para H2 ratio. In this Letter we explore the effect of the ortho-para (o-p) H2 conversion on grains on the deuteration timescale in fully-depleted dense cores, including the most relevant uncertainties that affect this complex process. We show that (I) the o-p H2 conversion on grains is not strongly influenced by the uncertainties on the conversion time and the sticking coefficient, and (II) that the process is controlled by the temperature and the residence time of ortho-H2 on the surface, I.e., by the binding energy. We find that for binding energies between 330 and 550 K, depending on the temperature, the o-p H2 conversion on grains can shorten the deuterium fractionation timescale by orders of magnitude, opening a new route for explaining the large observed deuteration fraction D frac in dense molecular cloud cores. Our results suggest that the star formation timescale, when estimated through the timescale to reach the observed deuteration fractions, might be shorter than previously proposed. However, more accurate measurements of the binding energy are needed in order to better assess the overall role of this process.

Multiple mechanisms of PCB neurotoxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carpenter, D.O.; Stoner, C.T.; Lawrence, D.A.

1996-12-31

Polychlorinated biphenyls (PCBs) have been implicated in cancer, but many of the symptoms in humans exposed to PCBs are related to the nervous system and behavior. We demonstrated three different direct mechanisms whereby PCBs are neurotoxic in rats. By using flow cytometry, we demonstrated that the orthosubstituted PCB congener 2,4,4{prime}, but neither TCDD nor the coplanar PCB congener 3,4,5,3{prime},4{prime}, causes rapid death of cerebellar granule cells. The ortho-substituted congener 2,4,4{prime} reduced long-term potentiation, an indicator of cognitive potential, in hippocampal brain slices, but a similar effect was observed for the coplanar congener 3,4,3{prime},4{prime}, indicating that this effect may be causedmore » by both ortho- and coplanar congeners by mechanisms presumably not mediated via the Ah receptor. It was previously shown that some ortho-substituted PCB congeners cause a reduction in levels of the neurotransmitter dopamine, and we present in vitro and in vivo evidence that this is due to reduction of synthesis of dopamine via inhibition of the enzyme tyrosine hydroxylase. Thus, PCBs have a variety of mechanisms of primary neurotoxicity, and neurotoxicity is a characteristic of ortho-substituted, non-dioxin-like congeners as well as some coplanar congeners. The relative contribution of each of these mechanisms to the loss of cognitive function in humans exposed to PCBs remains to be determined. 42 refs., 3 figs., 1 tab.« less

Semi-empirical study of ortho-cresol photo degradation in manganese-doped zinc oxide nanoparticles suspensions

PubMed Central

2012-01-01

The optimization processes of photo degradation are complicated and expensive when it is performed with traditional methods such as one variable at a time. In this research, the condition of ortho-cresol (o-cresol) photo degradation was optimized by using a semi empirical method. First of all, the experiments were designed with four effective factors including irradiation time, pH, photo catalyst’s amount, o-cresol concentration and photo degradation % as response by response surface methodology (RSM). The RSM used central composite design (CCD) method consists of 30 runs to obtain the actual responses. The actual responses were fitted with the second order algebraic polynomial equation to select a model (suggested model). The suggested model was validated by a few numbers of excellent statistical evidences in analysis of variance (ANOVA). The used evidences include high F-value (143.12), very low P-value (<0.0001), non-significant lack of fit, the determination coefficient (R2 = 0.99) and the adequate precision (47.067). To visualize the optimum, the validated model simulated the condition of variables and response (photo degradation %) be using a few number of three dimensional plots (3D). To confirm the model, the optimums were performed in laboratory. The results of performed experiments were quite close to the predicted values. In conclusion, the study indicated that the model is successful to simulate the optimum condition of o-cresol photo degradation under visible-light irradiation by manganese doped ZnO nanoparticles. PMID:22909072

Ortho-Rectification of Narrow Band Multi-Spectral Imagery Assisted by Dslr RGB Imagery Acquired by a Fixed-Wing Uas

NASA Astrophysics Data System (ADS)

Rau, J.-Y.; Jhan, J.-P.; Huang, C.-Y.

2015-08-01

Miniature Multiple Camera Array (MiniMCA-12) is a frame-based multilens/multispectral sensor composed of 12 lenses with narrow band filters. Due to its small size and light weight, it is suitable to mount on an Unmanned Aerial System (UAS) for acquiring high spectral, spatial and temporal resolution imagery used in various remote sensing applications. However, due to its wavelength range is only 10 nm that results in low image resolution and signal-to-noise ratio which are not suitable for image matching and digital surface model (DSM) generation. In the meantime, the spectral correlation among all 12 bands of MiniMCA images are low, it is difficult to perform tie-point matching and aerial triangulation at the same time. In this study, we thus propose the use of a DSLR camera to assist automatic aerial triangulation of MiniMCA-12 imagery and to produce higher spatial resolution DSM for MiniMCA12 ortho-image generation. Depending on the maximum payload weight of the used UAS, these two kinds of sensors could be collected at the same time or individually. In this study, we adopt a fixed-wing UAS to carry a Canon EOS 5D Mark2 DSLR camera and a MiniMCA-12 multi-spectral camera. For the purpose to perform automatic aerial triangulation between a DSLR camera and the MiniMCA-12, we choose one master band from MiniMCA-12 whose spectral range has overlap with the DSLR camera. However, all lenses of MiniMCA-12 have different perspective centers and viewing angles, the original 12 channels have significant band misregistration effect. Thus, the first issue encountered is to reduce the band misregistration effect. Due to all 12 MiniMCA lenses being frame-based, their spatial offsets are smaller than 15 cm and all images are almost 98% overlapped, we thus propose a modified projective transformation (MPT) method together with two systematic error correction procedures to register all 12 bands of imagery on the same image space. It means that those 12 bands of images acquired at the same exposure time will have same interior orientation parameters (IOPs) and exterior orientation parameters (EOPs) after band-to-band registration (BBR). Thus, in the aerial triangulation stage, the master band of MiniMCA-12 was treated as a reference channel to link with DSLR RGB images. It means, all reference images from the master band of MiniMCA-12 and all RGB images were triangulated at the same time with same coordinate system of ground control points (GCP). Due to the spatial resolution of RGB images is higher than the MiniMCA-12, the GCP can be marked on the RGB images only even they cannot be recognized on the MiniMCA images. Furthermore, a one meter gridded digital surface model (DSM) is created by the RGB images and applied to the MiniMCA imagery for ortho-rectification. Quantitative error analyses show that the proposed BBR scheme can achieve 0.33 pixels of average misregistration residuals length and the co-registration errors among 12 MiniMCA ortho-images and between MiniMCA and Canon RGB ortho-images are all less than 0.6 pixels. The experimental results demonstrate that the proposed method is robust, reliable and accurate for future remote sensing applications.

Diagnostic and prognostic value of cardiac troponin I assays in patients admitted with symptoms suggestive of acute coronary syndrome.

PubMed

Apple, Fred S; Quist, Heidi E; Murakami, MaryAnn M

2004-04-01

Increasing numbers of patients are presenting to emergency departments with symptoms suggestive of an acute myocardial infarction. To demonstrate the comparative performance of the Ortho Vitros Troponin I and Beckman Access AccuTnI assays used to detect myocardial infarction and to develop risk stratification schemes for all-cause death in patients who presented with myocardial ischemia symptoms that were suggestive of acute coronary syndrome (ACS). The prospective enrollment of patients with ACS and the measurement of serial plasma samples by 2 commercial cardiac troponin I (cTnI) assays. A metropolitan medical center that admitted patients with ACS during a 2-month period. The study population consisted of 200 consecutively admitted patients who presented with symptoms that were suggestive of ACS. Correlation scatterplots showed no significant bias between cTnI assays based on 659 specimens across the dynamic range of each assay. Only minor differences in slopes and intercepts were observed between assays when correlations were based across selected concentration ranges. The receiver operating characteristic curve areas for the detection of myocardial infarction were not significantly different (Ortho,.991; Beckman,.995). At the 99th percentile (Beckman, 0.04 microg/L; Ortho, 0.08 microg/L), each assay demonstrated 100% sensitivity with 78% and 80% specificity, respectively. Kaplan-Meier survival curves and the log-rank test were used to compare time-to-event data. Patients with increased baseline cTnI values had higher odds ratios of death than did those with normal concentrations. For Ortho, the 99th percentile cutoff was 5.9, and the 10% coefficient of variation cutoff was 10.3; for Beckman, the 99th percentile cutoff was 31.4, and the 10% coefficient of variation cutoff was 15.3. Comparable diagnostic and risk stratification abilities were demonstrated in patients with ACS by the Ortho Vitros and Beckman Access cTnI assays, with no significant analytic bias between cTnI assays.

Quenching of triplet-excited flavins by flavonoids. Structural assessment of antioxidative activity.

PubMed

Huvaere, Kevin; Olsen, Karsten; Skibsted, Leif H

2009-10-02

The mechanism of flavin-mediated photooxidation of flavonoids was investigated for aqueous solutions. Interaction of triplet-excited flavin mononucleotide with phenols, as determined by laser flash photolysis, occurred at nearly diffusion-controlled rates (k approximately 1.6 x 10(9) L mol(-1) s(-1) for phenol at pH 7, 293 K), but protection of the phenolic function by methylation inhibited reaction. Still, electron transfer was proposed as the dominating mechanism due to the lack of primary kinetic hydrogen/deuterium isotope effect and the low activation enthalpy (<20 kJ mol(-1)) for photooxidation. Activation entropy worked compensating in a series of phenolic derivatives, supporting a common oxidation mechanism. An ortho-hydroxymethoxy pattern was equally reactive (k approximately 2.3 x 10(9) L mol(-1) s(-1) for guaiacol at pH 7) as compounds with ortho-dihydroxy substitution (k approximately 2.4 x 10(9) L mol(-1) s(-1) for catechol at pH 7), which are generally referred to as good antioxidants. This refutes the common belief that stabilization of incipient phenoxyl radicals through intramolecular hydrogen bonding is the driving force behind the reducing activity of catechol-like compounds. Instead, such bonding improves ionization characteristics of the substrates, hence the differences in reactivity with (photo)oxidation of isolated phenols. Despite the similar reactivity, radicals from ortho-dihydroxy compounds are detected in high steady-state concentrations by electron paramagnetic resonance (EPR) spectroscopy, while those resulting from oxidation of ortho-hydroxymethoxy (or isolated phenolic) patterns were too reactive to be observed. The ability to deprotonate and form the corresponding radical anions at neutral pH was proposed as the decisive factor for stabilization and, consequently, for antioxidative action. Thus, substituting other ionizable functions for the ortho- or para-hydroxyl in phenolic compounds resulted in stable radical anion formation, as demonstrated for para-hydroxybenzoic acid, in contrast to its methyl ester.

Herschel/HIFI observations of the circumstellar ammonia lines in IRC+10216

NASA Astrophysics Data System (ADS)

Schmidt, M. R.; He, J. H.; Szczerba, R.; Bujarrabal, V.; Alcolea, J.; Cernicharo, J.; Decin, L.; Justtanont, K.; Teyssier, D.; Menten, K. M.; Neufeld, D. A.; Olofsson, H.; Planesas, P.; Marston, A. P.; Sobolev, A. M.; de Koter, A.; Schöier, F. L.

2016-08-01

Context. A discrepancy exists between the abundance of ammonia (NH3) derived previously for the circumstellar envelope (CSE) of IRC+10216 from far-IR submillimeter rotational lines and that inferred from radio inversion or mid-infrared (MIR) absorption transitions. Aims: To address the discrepancy described above, new high-resolution far-infrared (FIR) observations of both ortho- and para-NH3 transitions toward IRC+10216 were obtained with Herschel, with the goal of determining the ammonia abundance and constraining the distribution of NH3 in the envelope of IRC+10216. Methods: We used the Heterodyne Instrument for the Far Infrared (HIFI) on board Herschel to observe all rotational transitions up to the J = 3 level (three ortho- and six para-NH3 lines). We conducted non-LTE multilevel radiative transfer modelling, including the effects of near-infrared (NIR) radiative pumping through vibrational transitions. The computed emission line profiles are compared with the new HIFI data, the radio inversion transitions, and the MIR absorption lines in the ν2 band taken from the literature. Results: We found that NIR pumping is of key importance for understanding the excitation of rotational levels of NH3. The derived NH3 abundances relative to molecular hydrogen were (2.8 ± 0.5) × 10-8 for ortho-NH3 and for para-NH3, consistent with an ortho/para ratio of 1. These values are in a rough agreement with abundances derived from the inversion transitions, as well as with the total abundance of NH3 inferred from the MIR absorption lines. To explain the observed rotational transitions, ammonia must be formed near to the central star at a radius close to the end of the wind acceleration region, but no larger than about 20 stellar radii (1σ confidence level). Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. HIFI is the Herschel Heterodyne Instrument for the Far Infrared.The reduced spectra (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A131

Non-metallocene organometallic complexes and related methods and systems

DOEpatents

Agapie, Theodor; Golisz, Suzanne Rose; Tofan, Daniel; Bercaw, John E.

2010-12-07

A non-metallocene organometallic complex comprising a tridentate ligand and a metal bonded to a tridentate ligand, wherein two substituted aryl groups in the tridentate ligand are connected to a cyclic group at the ortho position via semi-rigid ring-ring linkages, and selected so to provide the resulting non-metallocene organometallic complex with a C.sub.S geometry, a C.sub.1 geometry, a C.sub.2 geometry or a C.sub.2v geometry. Method for performing olefin polymerization with a non-metallocene organometallic complex as a catalyst, related catalytic systems, tridentate ligand and method for providing a non-metallocene organometallic complex.

Pyrene-Containing ortho-Oligo(phenylene)ethynylene Foldamer as a Ratiometric Probe Based on Circularly Polarized Luminescence.

PubMed

Reiné, Pablo; Justicia, Jose; Morcillo, Sara P; Abbate, Sergio; Vaz, Belen; Ribagorda, María; Orte, Ángel; Álvarez de Cienfuegos, Luis; Longhi, Giovanna; Campaña, Araceli G; Miguel, Delia; Cuerva, Juan M

2018-04-20

In this manuscript, we report the first synthesis of an organic monomolecular emitter, which behaves as a circularly polarized luminescence (CPL)-based ratiometric probe. The enantiopure helical ortho-oligo(phenylene)ethynylene ( o-OPE) core has been prepared by a new and efficient macrocyclization reaction. The combination of such o-OPE helical skeleton and a pyrene couple leads to two different CPL emission features in a single structure whose ratio linearly responds to silver(I) concentration.

Rotation of molecular hydrogen in Si: unambiguous identification of ortho-H(2) and para-D(2).

PubMed

Chen, E Elinor; Stavola, Michael; Beall Fowler, W; Zhou, J Anna

2002-06-17

The 3618.4 and 2642.6 cm(-1) infrared absorption lines of interstitial H(2) and D(2) in silicon have been studied under applied uniaxial stresses. The resulting splittings and their small dependence on isotope establish that H(2) in Si is a nearly free rotor and that these lines arise from vibrational transitions between rovibrational states with rotational quantum number J = 1 (T(2) in T(d) symmetry) for ortho-H(2) and para-D(2).

Access to 6a-Alkyl Aporphines: Synthesis of (±)-N-Methylguattescidine.

PubMed

Ku, Angela F; Cuny, Gregory D

2016-10-21

(-)-N-Methylguattescidine (3) is an alkaloid recently isolated from Fissistigma latifolium and assigned as a rare example of a 6a-alkyl aporphine. Herein, we report the synthesis of (±)-3 and the des-hydroxyl derivative 4 using our previously reported ortho-phenol arylation methodology mediated by the XPhos precatalyst as a key synthetic step. In addition, substituents on the aryl halide portion of the ortho-phenol arylation substrates significantly influenced the formation of an oxidized side product.

New Polyisoimides: An Approach to In Situ Rigid-Rod Polyimide Formation

DTIC Science & Technology

1987-10-01

substitution, hut because of the highly activated chloro leaving groups ( ortho to a nitro group) it was determined that only a stoichiometric equivalent was...dianhydride (0.5985 g, 2.740 mmol), 24 ml of freshly distilled m- cresol , and six drops of isoquinoline. After the diamine dissolved, 15 ml of toluene were...0 Um cyv W C4 0 LL z 0 20 AFIUAL-TR-87-4071 derivative. Tt was suggested, with good cause, that a pendent group located in the three position ( ortho

Ortho Image and DTM Generation with Intelligent Methods

NASA Astrophysics Data System (ADS)

Bagheri, H.; Sadeghian, S.

2013-10-01

Nowadays the artificial intelligent algorithms has considered in GIS and remote sensing. Genetic algorithm and artificial neural network are two intelligent methods that are used for optimizing of image processing programs such as edge extraction and etc. these algorithms are very useful for solving of complex program. In this paper, the ability and application of genetic algorithm and artificial neural network in geospatial production process like geometric modelling of satellite images for ortho photo generation and height interpolation in raster Digital Terrain Model production process is discussed. In first, the geometric potential of Ikonos-2 and Worldview-2 with rational functions, 2D & 3D polynomials were tested. Also comprehensive experiments have been carried out to evaluate the viability of the genetic algorithm for optimization of rational function, 2D & 3D polynomials. Considering the quality of Ground Control Points, the accuracy (RMSE) with genetic algorithm and 3D polynomials method for Ikonos-2 Geo image was 0.508 pixel sizes and the accuracy (RMSE) with GA algorithm and rational function method for Worldview-2 image was 0.930 pixel sizes. For more another optimization artificial intelligent methods, neural networks were used. With the use of perceptron network in Worldview-2 image, a result of 0.84 pixel sizes with 4 neurons in middle layer was gained. The final conclusion was that with artificial intelligent algorithms it is possible to optimize the existing models and have better results than usual ones. Finally the artificial intelligence methods, like genetic algorithms as well as neural networks, were examined on sample data for optimizing interpolation and for generating Digital Terrain Models. The results then were compared with existing conventional methods and it appeared that these methods have a high capacity in heights interpolation and that using these networks for interpolating and optimizing the weighting methods based on inverse distance leads to a high accurate estimation of heights.

A C-band broadband ortho-mode transducer for radioastronomy polarimetry.

PubMed

Ferreira, Ivan S; Tello, Camilo; Bergano, Miguel; Villela, Thyrso; Barbosa, Domingos; Smoot, George F

2016-01-01

We describe the design, the construction and performance of a narrow band ortho-mode transducer, currently used in the 5 GHz polarimetric receiver of the Galactic Emission Mapping project. The ortho-mode transducer was designed to achieve a high degree of transmission within the 400 MHz of the GEM band around the 5 GHz (4.8-5.2 GHz). It is composed of a circular-to-square waveguide transition, a septum polarizer, a thin waveguide coupler and a smooth square-to-rectangular waveguide transition with custom waveguide bends to the output ports. Our simulations and measurements show a very low level of cross-polarization of about -60 dB and a good impedance match for all three ports (S11; S22; S33 < -30 dB) with only 0:25 dB of insertion loss offset across the 400 MHz (4.8-5.2 GHz) of the reception bandwidth.

How to regulate energy levels and hole mobility of spiro-type hole transport materials in perovskite solar cells.

PubMed

Chi, Wei-Jie; Sun, Ping-Ping; Li, Ze-Sheng

2016-10-21

Methoxyaniline-based organic small molecules with three-dimensional structure have been proven as the most promising hole conductor for state-of-the-art perovskite devices. A fundamental understanding of the electronic properties and hole transport behavior of spiro-CPDT analogues, which is dependent on the number and position of the -OCH 3 groups, is significant for their potential applications as hole transport materials of perovskite solar cells. Our results from density functional theory calculations indicate that meta-substitution is more beneficial to reduce the highest occupied molecular orbital (HOMO) levels of molecules compared with ortho- and para-substitution. Furthermore, the hole mobility can be improved by ortho-substitution or mixed ortho- and para-substitution. Most interestingly, it is found that the improvement in hole mobility is at the expense of raising the HOMO level of spiro-CPDT analogues. These results can be useful in the process of designing and synthesizing excellent hole transport materials with suitable HOMO levels and high hole mobility.

Results and evaluation of the first study of organochlorine contaminants (PCDDs, PCDFs, PCBs and DDTs), heavy metals and metalloids in birds from Baja California, México.

PubMed

Jiménez, Begoña; Rodríguez-Estrella, Ricardo; Merino, Rubén; Gómez, Gema; Rivera, Laura; José González, María; Abad, Esteban; Rivera, Josep

2005-01-01

Organochlorine compounds (OCs) including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p-p'-DDE), heavy metals (Pb, Cd, Zn, Cu), and arsenic were measured in house sparrows (Passer domesticus) and common ground doves (Columbina passerina) from Baja California Sur, México. Concentrations of PCDD/Fs were low, with 21 pg/g for house sparrows, and 7.7 pg/g for common ground doves. Non-ortho-PCB concentrations in house sparrow and common ground doves were 58 and 254 pg/g, respectively, and are within the highest concentrations reported in species that are in the low levels of food webs. The major differences in organochlorine levels between species were found for ortho-PCBs and DDTs. ortho-PCB levels were higher in the seedeater species, whereas DDT levels were higher in the omnivorous species. Heavy metal levels were far below those associated with negative effects.

Quantum-tunneling isotope-exchange reaction H2+D-→HD +H-

NASA Astrophysics Data System (ADS)

Yuen, Chi Hong; Ayouz, Mehdi; Endres, Eric S.; Lakhamanskaya, Olga; Wester, Roland; Kokoouline, Viatcheslav

2018-02-01

The tunneling reaction H2+D-→HD +H- was studied in a recent experimental work at low temperatures (10, 19, and 23 K) by Endres et al. [Phys. Rev. A 95, 022706 (2017), 10.1103/PhysRevA.95.022706]. An upper limit of the rate coefficient was found to be about 10-18cm3 /s. In the present study, reaction probabilities are determined using the ABC program developed by Skouteris et al. [Comput. Phys. Commun. 133, 128 (2000), 10.1016/S0010-4655(00)00167-3]. The probabilities for ortho-H2 and para-H2 in their ground rovibrational states are obtained numerically at collision energies above 50 meV with the total angular momentum J =0 -15 and extrapolated below 50 meV using a WKB approach. Thermally averaged rate coefficients for ortho- and para-H2 are obtained; the largest one, for ortho-H2, is about 3.1 ×10-20cm3 /s, which agrees with the experimental results.

Electrophilic and free radical nitration of benzene and toluene with various nitrating agents*

PubMed Central

Olah, George A.; Lin, Henry C.; Olah, Judith A.; Narang, Subhash C.

1978-01-01

Electrophilic nitration of toluene and benzene was studied under various conditions with several nitrating systems. It was found that high orthopara regioselectivity is prevalent in all reactions and is independent of the reactivity of the nitrating agent. The methyl group of toluene is predominantly ortho-para directing under all reaction conditions. Steric factors are considered to be important but not the sole reason for the variation in the ortho/para ratio. The results reinforce our earlier views that, in electrophilic aromatic nitrations with reactive nitrating agents, substrate and positional selectivities are determined in two separate steps. The first step involves a π-aromatic-NO2+ ion complex or encounter pair, whereas the subsequent step is of arenium ion nature (separate for the ortho, meta, and para positions). The former determines substrate selectivity, whereas the latter determines regioselectivity. Thermal free radical nitration of benzene and toluene with tetranitromethane in sharp contrast gave nearly statistical product distributions. PMID:16592503

Hyperfine excitation of linear molecules by para- and ortho-H{sub 2}: Application to the HCl–H{sub 2} system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lanza, Mathieu; Lique, François, E-mail: francois.lique@univ-lehavre.fr

The determination of hyperfine structure resolved excitation cross sections and rate coefficients due to H{sub 2} collisions is required to interpret astronomical spectra. In this paper, we present several theoretical approaches to compute these data. An almost exact recoupling approach and approximate sudden methods are presented. We apply these different approaches to the HCl–H{sub 2} collisional system in order to evaluate their respective accuracy. HCl–H{sub 2} hyperfine structure resolved cross sections and rate coefficients are then computed using recoupling and approximate sudden methods. As expected, the approximate sudden approaches are more accurate when the collision energy increases and the resultsmore » suggest that these approaches work better for para-H{sub 2} than for ortho-H{sub 2} colliding partner. For the first time, we present HCl–H{sub 2} hyperfine structure resolved rate coefficients, computed here for temperatures ranging from 5 to 300 K. The usual Δj{sub 1} = ΔF{sub 1} propensity rules are observed for the hyperfine transitions. The new rate coefficients will significantly help the interpretation of interstellar HCl emission lines observed with current and future telescopes. We expect that these new data will allow a better determination of the HCl abundance in the interstellar medium, that is crucial to understand the interstellar chlorine chemistry.« less

Thermal degradation of polybrominated diphenyl ethers over as-prepared Fe3O4 micro/nano-material and hypothesized mechanism.

PubMed

Li, Qianqian; Yang, Fan; Su, Guijin; Huang, Linyan; Lu, Huijie; Zhao, Yuyang; Zheng, Minghui

2016-01-01

The thermal degradation of decabromodiphenyl ether (BDE-209) featuring fully substituted bromines was investigated over an as-prepared Fe3O4 micro/nano-material at 300 °C. Degradation followed pseudo-first-order kinetics with kobs = 0.15 min(-1) higher than that for decachlorobiphenyl (CB-209). Twenty-six newly produced polybrominated diphenyl ether (PBDE) congeners were identified using the available PBDE standards, while four PBDE congener products were predicted using third-order polynomial regression equation. Analysis of the products indicated that BDE-209 underwent stepwise hydrodebromination over as-prepared Fe3O4. Similar to the case for CB-209, two initial hydrodebromination steps are favored at the BDE-209 meta-positions, giving the major products BDE-207 and BDE-197. However, the variance about the preferred products began to emerge from the start of heptabromodiphenyl ethers (hepta-BDEs). The majorly produced hepta-BDE isomer with BDE-183 is unbrominated at one ortho-position. However, this is different from the reported degradation of CB-209, which always produced the products chlorinated at all four ortho-positions until the ortho-position had to be removed for the formation of trichlorobiphenyls and dichlorobiphenyl still majorly chlorinated at three or two ortho-positions. The early BDE-209 hydrodebromination steps appear to be strongly influenced by steric effects, whereas subsequent hydrodebromination steps, as more bromine atoms are removed, will be gradually governed more by thermodynamics.

Bacterial entombment by intratubular mineralization following orthograde mineral trioxide aggregate obturation: a scanning electron microscopy study

PubMed Central

Yoo, Jun Sang; Chang, Seok-Woo; Oh, So Ram; Perinpanayagam, Hiran; Lim, Sang-Min; Yoo, Yeon-Jee; Oh, Yeo-Rok; Woo, Sang-Bin; Han, Seung-Hyun; Zhu, Qiang; Kum, Kee-Yeon

2014-01-01

The time domain entombment of bacteria by intratubular mineralization following orthograde canal obturation with mineral trioxide aggregate (MTA) was studied by scanning electron microscopy (SEM). Single-rooted human premolars (n=60) were instrumented to an apical size #50/0.06 using ProFile and treated as follows: Group 1 (n=10) was filled with phosphate buffered saline (PBS); Group 2 (n=10) was incubated with Enterococcus faecalis for 3 weeks, and then filled with PBS; Group 3 (n=20) was obturated orthograde with a paste of OrthoMTA (BioMTA, Seoul, Korea) and PBS; and Group 4 (n=20) was incubated with E. faecalis for 3 weeks and then obturated with OrthoMTA–PBS paste. Following their treatments, the coronal openings were sealed with PBS-soaked cotton and intermediate restorative material (IRM), and the roots were then stored in PBS for 1, 2, 4, 8 or 16 weeks. After each incubation period, the roots were split and their dentin/MTA interfaces examined in both longitudinal and horizontal directions by SEM. There appeared to be an increase in intratubular mineralization over time in the OrthoMTA-filled roots (Groups 3 and 4). Furthermore, there was a gradual entombment of bacteria within the dentinal tubules in the E. faecalis inoculated MTA-filled roots (Group 4). Therefore, the orthograde obturation of root canals with OrthoMTA mixed with PBS may create a favorable environment for bacterial entombment by intratubular mineralization. PMID:25012869

Effect of Different Types of Toothpaste on the Frictional Resistance Between Orthodontic Stainless Steel Brackets and Wires.

PubMed

Hosseinzadeh Nik, Tahereh; Hooshmand, Tabassom; Farhadifard, Homa

2017-09-01

The purpose of this study was to investigate the effect of different types of toothpaste on the frictional resistance between stainless steel brackets and archwires. Ninety stainless steel orthodontic brackets with stainless steel wires were bonded to bovine teeth and were divided into 6 groups for application of the following toothpastes: Colgate® Total® Advanced Whitening, Colgate® Total® Pro Gum Health, Colgate® Anticavity, Ortho.Kin®, and Sunstar GUM® Ortho toothpastes. No toothpaste was applied in the control group. Each group was brushed by a brushing machine with the use of the designated solution for 4.5 minutes. The frictional force was measured in a universal testing machine with a crosshead speed of 10 mm/minute over a 5-mm archwire. Data were analyzed using one-way analysis of variance (ANOVA) at the 0.05 significance level. The frictional resistance values of Ortho.Kin® and GUM® Ortho toothpastes and the control group were not significantly different (P>0.05). However, there were significant differences between the frictional resistance values of Colgate® Total® Pro Gum Health and Colgate® Anticavity toothpastes with that of the control group (P<0.05). The highest and lowest frictional resistance values were related to Colgate® Total® Pro Gum Health toothpaste and the control group, respectively. Among the evaluated toothpastes, the orthodontic toothpastes did not increase the frictional resistance between the orthodontic stainless steel brackets and wires.

Inhibitory mechanism of phthalate esters on Karenia brevis.

PubMed

Liu, Ning; Wen, Fuling; Li, Fengmin; Zheng, Xiang; Liang, Zhi; Zheng, Hao

2016-07-01

The occurrence of phthalate esters (PAEs), a class of widely used and environmentally prevalent chemicals, raises concern to environmental and human health globally. The PAEs have been demonstrated to inhibit algae growth, but the underlying mechanisms remain unclear. In this research, diethyl ortho-phthalate (DEP), diallyl phthalate (DAP), di-n-butyl ortho-phthalate (DBP), di-iso-butyl ortho-phthalate, and benzyl-n-butyl ortho-phthalate (BBP) were screened from 11 species of PAEs to study their inhibitory effects on Karenia brevis and determine their target sites on algae. With increasing the alkyl chains of these five PAEs, the values of EC50,96h decreased. The content of malondialdehyde increased with the continuous accumulation of reactive oxygen species (ROS) in the algae cells. Moreover, the superoxide dismutase and catalase contents were first activated and then inhibited. The ultrastructures of Karenia brevis cells were detected by transmission electron microscopy, and cells treated with PAEs exhibiting distorted shapes and large vacuoles. Thus, the algae were damaged by ROS accumulation, resulting in lipid oxidation and algal growth inhibition. The inhibitors of the electron transport chain showed that the sites of ROS production and accumulation in K. brevis cells under DEP and BBP were the mitochondria and chloroplast, respectively. Moreover, the target sites of DAP and DBP were both the chloroplast and mitochondria. These results are useful for controlling PAEs contamination in and revealing the fate of PAEs in aquatic ecosystem. Copyright © 2016 Elsevier Ltd. All rights reserved.

Distinct charge orders in the planes and chains of ortho-III-ordered YBa2Cu3O(6+δ) superconductors identified by resonant elastic x-ray scattering.

PubMed

Achkar, A J; Sutarto, R; Mao, X; He, F; Frano, A; Blanco-Canosa, S; Le Tacon, M; Ghiringhelli, G; Braicovich, L; Minola, M; Sala, M Moretti; Mazzoli, C; Liang, Ruixing; Bonn, D A; Hardy, W N; Keimer, B; Sawatzky, G A; Hawthorn, D G

2012-10-19

Recently, charge density wave (CDW) order in the CuO(2) planes of underdoped YBa(2)Cu(3)O(6+δ) was detected using resonant soft x-ray scattering. An important question remains: is the chain layer responsible for this charge ordering? Here, we explore the energy and polarization dependence of the resonant scattering intensity in a detwinned sample of YBa(2)Cu(3)O(6.75) with ortho-III oxygen ordering in the chain layer. We show that the ortho-III CDW order in the chains is distinct from the CDW order in the planes. The ortho-III structure gives rise to a commensurate superlattice reflection at Q=[0.33 0 L] whose energy and polarization dependence agrees with expectations for oxygen ordering and a spatial modulation of the Cu valence in the chains. Incommensurate peaks at [0.30 0 L] and [0 0.30 L] from the CDW order in the planes are shown to be distinct in Q as well as their temperature, energy, and polarization dependence, and are thus unrelated to the structure of the chain layer. Moreover, the energy dependence of the CDW order in the planes is shown to result from a spatial modulation of energies of the Cu 2p to 3d(x(2)-y(2)) transition, similar to stripe-ordered 214 cuprates.

Structure, internal mobility, and spectrum of the ammonia dimer: Calculation of the vibration-rotation-tunneling states

NASA Astrophysics Data System (ADS)

Olthof, E. H. T.; van der Avoird, A.; Wormer, P. E. S.

1994-11-01

We have obtained a potential for (NH3)2 by calculating the six-dimensional vibra- tion-rotation-tunneling (VRT) states from a model potential with some variable parameters, and adjusting some calculated transition frequencies to the observed far-infrared spectrum. The equilibrium geometry is strongly bent away from a linear hydrogen bonded structure. Equivalent minima with the proton donor and acceptor interchanged are separated by a barrier of only 7 cm-1. The barriers to rotation of the monomers about their C3 axes are much higher. The VRT levels from this potential agree to about 0.25 cm-1 with all far-infrared frequencies of (NH3)2 observed for K=0, ‖K‖=1, and ‖K‖=2 and for all the symmetry species: Ai=ortho-ortho, Ei=para-para, and G=ortho-para. Moreover, the dipole moments and the nuclear quadrupole splittings agree well with the values that are observed for the G states. The potential has been explicitly transformed to the center-of-mass coordinates of (ND3)2 and used to study the effects of the deuteration on the VRT states. The observed decrease of the dipole moment and the (small) changes in the nuclear quadrupole splittings are well reproduced. It follows from our calculations that the ammonia dimer is highly nonrigid and that vibrational averaging effects are essential. Seemingly contradictory effects of this averaging on its properties are the consequence of the different hindered rotor behavior of ortho and para monomers.

Phenol and Benzoate Metabolism by Pseudomonas putida: Regulation of Tangential Pathways

PubMed Central

Feist, Carol F.; Hegeman, G. D.

1969-01-01

Catechol occurs as an intermediate in the metabolism of both benzoate and phenol by strains of Pseudomonas putida. During growth at the expense of benzoate, catechol is cleaved ortho (1,2-oxygenase) and metabolized via the β-ketoadipate pathway; during growth at the expense of phenol or cresols, the catechol or substituted catechols formed are metabolized by a separate pathway following meta (2,3-oxygenase) cleavage of the aromatic ring of catechol. It is possible to explain the mutually exclusive occurrence of the meta and ortho pathway enzymes in phenol- and benzoate-grown cells of P. putida on the basis of differences in the mode of regulation of these two pathways. By use of both nonmetabolizable inducers and blocked mutants, gratuitous synthesis of some of the meta pathway enzymes was obtained. All four enzymes of the meta pathway are induced by the primary substrate, cresol or phenol, or its analogue. Three enzymes of the ortho pathway that catalyze the conversion of catechol to β-ketoadipate enol-lactone are induced by cis,cis-muconate, produced from catechol by 1,2-oxygenase-mediated cleavage. Observations on the differences in specificity of induction and function of the two pathways suggest that they are not really either tangential or redundant. The meta pathway serves as a general mechanism for catabolism of various alkyl derivatives of catechol derived from substituted phenolic compounds. The ortho pathway is more specific and serves primarily in the catabolism of precursors of catechol and catechol itself. PMID:5354952

Application of Chan-Lam cross coupling for the synthesis of N-heterocyclic carbene precursors bearing strong electron donating or withdrawing groups

NASA Astrophysics Data System (ADS)

Huang, Liliang; He, Chengxiang; Sun, Zhihua

2015-07-01

Chan-Lam cross coupling allowed efficient synthesis of N,N’-disubstituted ortho-phenylene diamines bearing strong electron donating or withdrawing groups, such as nitro or methoxy groups, with moderate to high yields. These diamines can then be turned into N-heterocyclic carbene precursors after condensation with trimethyl orthoformate. The same strategy can also be utilized for the synthesis of N-monosubstituted aniline derivatives containing a functionalized ortho-aminomethyl group as intermediates for chiral 6-membered ring carbene precursors.

Mild Palladium Catalyzed ortho C-H Bond Functionalizations of Aniline Derivatives.

PubMed

Tischler, Ms Orsolya; Tóth, Mr Balázs; Novák, Zoltán

2017-02-01

This account collects the developments and transformations which avoid the utilization of harsh reaction conditions in the field of palladium catalyzed, ortho-directed C-H activation of aniline derivatives from the first attempts to up-to-date results, including the results of our research laboratory. The discussed functionalizations performed under mild conditions include acylation, olefination, arylation, alkylation, alkoxylation reactions. Beside the optimization studies and the synthetic applications mechanistic investigations are also presented. © 2017 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of High-Activity Para- to Ortho-Hydrogen Conversion Catalysts. Volume 2

DTIC Science & Technology

1989-09-28

Proc. Roy. Soc. London AllO, 464 (1925). 2 1929 Para- and ortho-hydrogen, Barmois, E., La Nature No. 2820, 400-1 (1929) C.A. 24,, 1020b. K. F...U.S. At. Energy Comm. LA -2719, 40 pp. (1962); cf. 3. Chem. Eng. Data 7, 179(1962). C.A. 58, 10750g. Schmidt number for normal hydrogen and...A-L);- p 181-9; in Eng. Briones, A. G.; Garcia de la Banda, J. F.; Inst. Quim. Fis. Quim., Madrid, Anales Real. Soc. Espan. Fis. Quim. (Madrid); Ser

Bridging the gap between homogeneous and heterogeneous catalysis: ortho/para H(2) conversion, hydrogen isotope scrambling, and hydrogenation of olefins by Ir(CO)Cl(PPh(3))(2).

PubMed

Matthes, Jochen; Pery, Tal; Gründemann, Stephan; Buntkowsky, Gerd; Sabo-Etienne, Sylviane; Chaudret, Bruno; Limbach, Hans-Heinrich

2004-07-14

Some transition metal complexes are known to catalyze ortho/para hydrogen conversion, hydrogen isotope scrambling, and hydrogenation reactions in liquid solution. Using the example of Vaska's complex, we present here evidence by NMR that the solvent is not necessary for these reactions to occur. Thus, solid frozen solutions or polycrystalline powdered samples of homogeneous catalysts may become heterogeneous catalysts. Comparative liquid- and solid-state studies provide novel insight into the reaction mechanisms.

Pressure-enhanced ortho-para conversion in solid hydrogen up to 58 GPa.

PubMed

Eggert, J H; Karmon, E; Hemley, R J; Mao, A; Goncharov, A F

1999-10-26

We measured the ortho-para conversion rate in solid hydrogen by using Raman scattering in a diamond-anvil cell, extending previous measurements by a factor of 60 in pressure. We confirm previous experiments that suggested a decrease in the conversion rate above about 0.5 GPa. We observe a distinct minimum at 3 GPa followed by a drastic increase in the conversion rate to our maximum pressure of 58 GPa. This pressure enhancement of conversion is not predicted by previous theoretical treatments and must be due to a new conversion pathway.

New ortho-para conversion mechanism in dense solid hydrogen.

PubMed

Strzhemechny, M A; Hemley, R J

2000-12-25

Analysis of recent measurements of striking changes in the rate of ortho-para conversion of solid H(2) up to 58 GPa shows that the conversion mechanism must differ from that at ambient pressure. A new conversion mechanism is identified in which the emerging excitations are coupled to the converting molecules via electric quadrupole-quadrupole rather than nuclear spin-spin interactions. The latter only initiates conversion while the coupling enhancement associated with the new mechanism is ensured by high compression and a gap closing, with the conversion energy diminishing strongly with increasing pressure.

A comparative analysis of the foamy and ortho virus capsid structures reveals an ancient domain duplication.

PubMed

Taylor, William R; Stoye, Jonathan P; Taylor, Ian A

2017-04-04

The Spumaretrovirinae (foamy viruses) and the Orthoretrovirinae (e.g. HIV) share many similarities both in genome structure and the sequences of the core viral encoded proteins, such as the aspartyl protease and reverse transcriptase. Similarity in the gag region of the genome is less obvious at the sequence level but has been illuminated by the recent solution of the foamy virus capsid (CA) structure. This revealed a clear structural similarity to the orthoretrovirus capsids but with marked differences that left uncertainty in the relationship between the two domains that comprise the structure. We have applied protein structure comparison methods in order to try and resolve this ambiguous relationship. These included both the DALI method and the SAP method, with rigorous statistical tests applied to the results of both methods. For this, we employed collections of artificial fold 'decoys' (generated from the pair of native structures being compared) to provide a customised background distribution for each comparison, thus allowing significance levels to be estimated. We have shown that the relationship of the two domains conforms to a simple linear correspondence rather than a domain transposition. These similarities suggest that the origin of both viral capsids was a common ancestor with a double domain structure. In addition, we show that there is also a significant structural similarity between the amino and carboxy domains in both the foamy and ortho viruses. These results indicate that, as well as the duplication of the double domain capsid, there may have been an even more ancient gene-duplication that preceded the double domain structure. In addition, our structure comparison methodology demonstrates a general approach to problems where the components have a high intrinsic level of similarity.

Comparative analysis of QSAR models for predicting pK(a) of organic oxygen acids and nitrogen bases from molecular structure.

PubMed

Yu, Haiying; Kühne, Ralph; Ebert, Ralf-Uwe; Schüürmann, Gerrit

2010-11-22

For 1143 organic compounds comprising 580 oxygen acids and 563 nitrogen bases that cover more than 17 orders of experimental pK(a) (from -5.00 to 12.23), the pK(a) prediction performances of ACD, SPARC, and two calibrations of a semiempirical quantum chemical (QC) AM1 approach have been analyzed. The overall root-mean-square errors (rms) for the acids are 0.41, 0.58 (0.42 without ortho-substituted phenols with intramolecular H-bonding), and 0.55 and for the bases are 0.65, 0.70, 1.17, and 1.27 for ACD, SPARC, and both QC methods, respectively. Method-specific performances are discussed in detail for six acid subsets (phenols and aromatic and aliphatic carboxylic acids with different substitution patterns) and nine base subsets (anilines, primary, secondary and tertiary amines, meta/para-substituted and ortho-substituted pyridines, pyrimidines, imidazoles, and quinolines). The results demonstrate an overall better performance for acids than for bases but also a substantial variation across subsets. For the overall best-performing ACD, rms ranges from 0.12 to 1.11 and 0.40 to 1.21 pK(a) units for the acid and base subsets, respectively. With regard to the squared correlation coefficient r², the results are 0.86 to 0.96 (acids) and 0.79 to 0.95 (bases) for ACD, 0.77 to 0.95 (acids) and 0.85 to 0.97 (bases) for SPARC, and 0.64 to 0.87 (acids) and 0.43 to 0.83 (bases) for the QC methods, respectively. Attention is paid to structural and method-specific causes for observed pitfalls. The significant subset dependence of the prediction performances suggests a consensus modeling approach.

Comparison of the efficacy of disinfectants in automated endoscope reprocessors for colonoscopes: tertiary amine compound (Sencron2®) versus ortho-phthalaldehyde (Cidex®OPA)

PubMed Central

Seo, Hyun Il; Lee, Dae Sung; Yoon, Eun Mi; Kwon, Min-Jung; Park, Hyosoon; Jung, Yoon Suk; Park, Jung Ho; Sohn, Chong Il

2016-01-01

Background/Aims To prevent the transmission of pathogens by endoscopes, following established reprocessing guidelines is critical. An ideal reprocessing step is simple, fast, and inexpensive. Here, we evaluated and compared the efficacy and safety of two disinfectants, a tertiary amine compound (TAC) and ortho-phthalaldehyde (OPA). Methods A total of 100 colonoscopes were randomly reprocessed using two same automated endoscope reprocessors, according to disinfectant. The exposure time was 10 minutes for 0.55% OPA (Cidex® OPA, Johnson & Johnson) and 5 minutes for 4% TAC (Sencron2®, Bab Gencel Pharma & Chemical Ind. Co.). Three culture samples were obtained from each colonoscope after reprocessing. Results A total of nine samples were positive among the 300 culture samples. The positive culture rate was not statistically different between the two groups (4% for OPA and 2% for TAC, P=0.501). There were no incidents related to safety during the study period. Conclusions TAC was non-inferior in terms of reprocessing efficacy to OPA and was safe to use. Therefore, TAC seems to be a good alternative disinfectant with a relatively short exposure time and is also less expensive than OPA. PMID:27175119

Understanding the Double Quantum Muonium RF Resonance

NASA Astrophysics Data System (ADS)

Kreitzman, S. R.; Cottrell, S. P.; Fleming, D. G.; Sun-Mack, S.

A physically intuitive analytical solution to the Mu + RF Hamiltonian and lineshape is developed. The method is based on reformulating the problem in a basis set that explicitly accounts for the 1q RF transitions and identifying an isolated upper 1q quasi-eigenstate within that basis. Subsequently the double quantum resonance explicitly manifests itself via the non-zero interaction term between the pair of lower ortho-normalized 1q basis states, which in this field region are substantially the | \\uparrow \\uparrow > and | \\downarrow \\downarrow > Mu states.

Despite court ruling, experts insist spermicides are safe.

PubMed

1985-03-01

Recently in Atlanta, Georgia, a US District Judge, Marvin Shoob, ordered Ortho Pharmaceutical Corporation to pay US$5.1 million in damages to a 3 year old girl, born with birth defects to a women who used a spermicide, manufactured by Ortho, when the child was conceived and for 4 weeks following conception. The child was born with a missing left arm, missing fingers on the right hand, a cleft palate, and impaired hearing. The spermicide, Ortho-Gynol, contains octoxynol, which prevents pregnancy by destroying the outer layer of sperm cells. The judge maintained that Ortho was negligent for failing to attach a label to the spermicide warning users that birth defects could occur if the product was used during pregnancy. In 1983, a Food and Drug Administration (FDA) advisory committee advised drug companies that is was unnecessary to attach such a label. The chairman of the committee, Ronald W. Nelson, still maintains that a warning label is unwarrented. "Contraceptive Technology Update" spoke with a number of family planning practitioners and several experts, including some who were involved in the case, concerning their views about the case. Most of the partitioners expressed surprise about the ruling, indicated that they did not plan to alter their counseling advise concerning spermicides, and believed that a warning label was not warranted. A representative for Ortho stated that the company still believes that there is no link between birth defects and the use of spermicides. Ortho does not plan to use a warning label. A spokesman from the judge's office said that the ruling pertained only to the specific case, and that the decision was not generalizable. Robert L. Brent, an expert witness for Ortho said that studies failed to find a significant association between birth defects and spermicides; however, he noted that researchers did not rule out the possibility that there was a slightly increased risk of birth defects among infants born to women who used spermicides. Bruce Buehler, an expert witness for the plaintiff, said that there was a probable link between the spermicide and the missing arm defect and a possible link between the spermicide and the missing fingers. He said that the damage probably occurred at some crucial developmental stage during the 4 weeks following conception rather than at the time of conception. A proponent for labeling is Herschel Jick. He and his colleagues conducted a study in 1981 of 763 women, who had prescriptions for spermicides filled within 600 days of pregnancy outcome, and of 3902 nonusers. 2.2% of the users, compared to 1.1% of the nonusers gave birth to infants with birth defects. The study has been criticized by experts for failing to isolate a well-defined syndrome among infants born to spermicide users and for failing to determine if and when those identified as users actually did use the prescribed spermicides. Jose Cordero of the Center for Disease Control noted that the Center does not have an official position concerning the issue, but that he did not feel that the evidence was strong enough to support claims of an association.

Simple ortho- and para-hydroquinones as compounds neuroprotective against oxidative stress in a manner associated with specific transcriptional activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Satoh, Takumi; Saitoh, Sachie; Hosaka, Manami

2009-02-06

Electrophilic compounds protect neurons through the activation of the Keap1/Nrf2 pathway and the induction of phase-2 enzymes [T. Satoh, S.A. Lipton, Redox regulation of neuronal survival by electrophilic compounds, Trends Neurosci. 30 (2007) 38-45; T. Satoh, S. Okamoto, J. Cui, Y. Watanabe, K. Furuta, M. Suzuki, K. Tohyama, S.A. Lipton, Activation of the Keap1/Nrf2 pathway for neuroprotection by electrophilic phase II inducers. Proc. Natl. Acad. Sci. USA 103 (2006) 768-773]. Hydroquinone-type electrophilic compounds such as tert-butyl hydroquinone (TBHQ) and carnosic acid (CA) have attracted special attention, because the oxidative conversion of 'hydroquinone' to 'quinone' is essential for the transcriptional activationmore » of the above-mentioned enzymes [T. Satoh, K. Kosaka, K. Itoh, A. Kobayashi, M. Yamamoto, Y. Shimojo, C. Kitajima, J. Cui, J. Kamins, S. Okamoto, T. Shirasawa, S.A. Lipton, Carnosic acid, a catechol-type electrophilic compound, protect neurons both in vitro and in vivo through activation of the Keap1/Nrf2 pathway via S-alkylation of specific cysteine, J. Neurochem. 104 (2008) 1161-1131; A.D. Kraft, D.A. Johnson, J.A. Johnson, Nuclear factor E2-related factor 2-dependent antioxidant response element activation by tert-butylhydroquinone and sulforaphane occurring preferentially in astrocytes conditions neurons against oxidative insult, J. Neurosci. 24 (2004) 1101-1112]. In the present study, we examined the relationship between electrophilicity and the protective effects afforded by electrophilic compounds. Electrophilicity was assessed in terms of the ability of a compound to bind to a cysteine on bovine serum albumin, by which we found that neuroprotective hydroquinones [TBHQ (para-) and CA (ortho-)] had distinctive patterns of cysteine binding compared with other electrophilic compounds. Further, we found that isomers of simple ortho- and para-hydroquinones such as 2-methylhydroquinone (para-) and 4-methyl-catechol (ortho-) [not in abstract] had similar properties of cysteine binding as TBHQ and CA, which compounds were associated with the transcriptional activation and an increase in the level of reduced glutathione. These results suggest that para- and ortho-dihydroquinones may be neuroprotective compounds active against oxidative stress.« less

Lipophilicity of potent porphyrin-based antioxidants. Comparison of ortho and meta isomers of Mn(III) N-alkylpyridylporphyrins

PubMed Central

Kos, Ivan; Rebouças, Júlio S.; DeFreitas-Silva, Gilson; Salvemini, Daniela; Vujaskovic, Zeljko; Dewhirst, Mark W.; Spasojevic, Ivan; Batinic-Haberle, Ines

2009-01-01

Mn(III) N-alkylpyridylporphyrins are among the most potent known SOD mimics and catalytic peroxynitrite scavengers, and modulators of redox-based cellular transcriptional activity. In addition to their intrinsic antioxidant capacity, bioavailability plays major role in their in vivo efficacy. While of identical antioxidant capacity, lipophilic MnTnHex-2-PyP is up to 120-fold more efficient in reducing oxidative stress injuries than hydrophilic MnTE-2-PyP. Due to limitations of analytical nature, porphyrin lipophilicity has been often estimated by thin-layer chromatographic Rf parameter, instead of the standard n-octanol/water partition coefficient, POW. Herein we used a new methodological approach to finally describe the MnP lipophilicity, by the conventional log POW means, for a series of biologically active ortho and meta isomers of Mn(III) N-alkylpyridylporphyrins. Three new porphyrins (MnTnBu-3-PyP, MnTnHex-3-PyP and MnTnHep-2-PyP) were synthesized to strengthen the conclusions. The log POW was linearly related to Rf and to the number of carbons in the alkyl chain (nC) for both isomer series; the meta isomers being 10-fold more lipophilic than the analogous ortho porphyrins. Increasing the length of the alkyl chain for 1 carbon atom increases the log POW value ~ 1 log unit with both isomers. Dramatic ~4 and ~5 orders of magnitude increase in lipophilicity of ortho isomers by extending pyridyl alkyl chains from 2 (MnTE-2-PyP, log POW = −6.25) to 6 (MnTnHex-2-PyP, log POW = −2.29) and 8 carbon atoms (MnTnOct-2-PyP, log POW = −0.77) parallels the increased efficacy in several oxidative-stress injury models, particularly those of the central nervous system where transport across the blood-brain barrier is critical. Although meta isomers are only slightly less potent SOD mimics and antioxidants than their ortho analogues, their higher lipophilicity and smaller bulkiness may lead to a higher cellular uptake and overall similar effectiveness in vivo. PMID:19361553

Levels of non-ortho-substituted (coplanar), mono- and di-ortho-substituted polychlorinated biphenyls, dibenzo-p-dioxins, and dibenzofurans in human serum and adipose tissue.

PubMed Central

Patterson, D G; Todd, G D; Turner, W E; Maggio, V; Alexander, L R; Needham, L L

1994-01-01

We have measured non-ortho-substituted (coplanar) polychlorinated biphenyl (PCB) levels as well as polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in human adipose tissue and serum collected in Atlanta, Georgia. The results show that the concentrations of the coplanar PCBs can be more than an order of magnitude higher than the concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin. Our measurements in pooled serum collected in 1982, 1988, and 1989 show a decrease in coplanar PCB levels from 1982 to 1989. We found that the pattern of relative amounts of coplanar PCBs in adipose tissue varied greatly from person to person unlike the PCDD and PCDF patterns, which were more nearly the same. Age was significantly correlated with the concentrations of 2,3,7,8-TCDD,3,3'4,4'-PCB, 3,3',4,4',5-PCB, and 3,3'4,4',5,5'-PCB in adipose tissue. We also measured levels of the mono- and di-ortho chlorine-substituted PCBs in human serum. The levels for some of these PCB congeners were three orders of magnitude higher than the coplanar PCBs, PCDDs, and PCDFs. We used the international toxicity equivalency factors (TEFs) for PCDDs and PCDFs and the TEFs proposed by Safe for PCBs to calculate the 2,3,7,8-TCDD equivalents. Four PCBs (3,3',4,4',5-; 2,3',4,4',5-;2,3,3',4,4'-;2,3,3',4,4',5-) make a larger contribution than 2,3,7,8-TCDD, while four other PCBs (3,3',4,4'5,5'-; 2,2',3,4,4',5'-;2,2',4,4',5,5'-;2,2',3,4,4',5,5'-) make nearly the same contribution as 2,3,7,8-TCDD. The mono-ortho-chlorine-substituted 2,3',4,4',5-PCB, however, is the major contributor to the total 2,3,7,8-TCDD equivalents in general population samples from the United States, Sweden, and Japan.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8187709

Nuclear spin/parity dependent spectroscopy and predissociation dynamics in vOH = 2 ← 0 overtone excited Ne-H2O clusters: Theory and experiment

NASA Astrophysics Data System (ADS)

Ziemkiewicz, Michael P.; Pluetzer, Christian; Loreau, Jérôme; van der Avoird, Ad; Nesbitt, David J.

2017-12-01

Vibrationally state selective overtone spectroscopy and state- and nuclear spin-dependent predissociation dynamics of weakly bound ortho- and para-Ne-H2O complexes (D0(ortho) = 34.66 cm-1 and D0(para) = 31.67 cm-1) are reported, based on near-infrared excitation of van der Waals cluster bands correlating with vOH = 2 ← 0 overtone transitions (|02-〉 and |02+〉) out of the ortho (101) and para (000) internal rotor states of the H2O moiety. Quantum theoretical calculations for nuclear motion on a high level potential energy surface [CCSD(T)/VnZf12 (n = 3, 4)], corrected for basis set superposition error and extrapolated to the complete basis set (CBS) limit, are employed to successfully predict and assign Π-Σ, Σ-Σ, and Σ-Π infrared bands in the spectra, where Σ or Π represent approximate projections of the body-fixed H2O angular momentum along the Ne-H2O internuclear axis. IR-UV pump-probe experimental capabilities permit real-time measurements of the vibrational predissociation dynamics, which indicate facile intramolecular vibrational energy transfer from the H2O vOH = 2 overtone vibrations into the VdWs (van der Waals) dissociation coordinate on the τprediss = 15-25 ns time scale. Whereas all predicted strong transitions in the ortho-Ne-H2O complexes are readily detected and assigned, vibrationally mediated photolysis spectra for the corresponding para-Ne-H2O bands are surprisingly absent despite ab initio predictions of Q-branch intensities with S/N > 20-40. Such behavior signals the presence of highly selective nuclear spin ortho-para predissociation dynamics in the upper state, for which we offer a simple mechanism based on Ne-atom mediated intramolecular vibrational relaxation in the H2O subunit (i.e., |02±〉 → {|01±〉; v2 = 2}), which is confirmed by the ab initio energy level predictions and the nascent OH rotational (N), spin orbit (Π1/2,3/2), and lambda doublet product distributions.

1-cyclohexyl-x-methoxybenzene derivatives, novel psychoactive substances seized on the internet market. Synthesis and in vivo pharmacological studies in mice.

PubMed

Fantinati, Anna; Ossato, Andrea; Bianco, Sara; Canazza, Isabella; De Giorgio, Fabio; Trapella, Claudio; Marti, Matteo

2017-05-01

Among novel psychoactive substances notified to EMCDDA and Europol were 1-cyclohexyl-x-methoxybenzene stereoisomers (ortho, meta, and para). These substances share some structural characteristics with phencyclidine and tramadol. Nowadays, no information on the pharmacological and toxicological effects evoked by 1-cyclohexyl-x-methoxybenzene are reported. The aim of this study was to investigate the effect evoked by each one stereoisomer on visual stimulation, body temperature, acute thermal pain, and motor activity in mice. Mice were evaluated in behavioral tests carried out in a consecutive manner according to the following time scheme: observation of visual placing response, measures of core body temperature, determination of acute thermal pain, and stimulated motor activity. All three stereoisomers dose-dependent inhibit visual placing response (rank order: meta > ortho > para), induce hyperthermia at lower and hypothermia at higher doses (meta > ortho > para) and cause analgesia to thermal stimuli (para > meta = ortho), while they do not alter motor activity. For the first time, this study demonstrates that systemic administration of 1-cyclohexyl-x-methoxybenzene compounds markedly inhibit visual response, promote analgesia, and induce core temperature alterations in mice. This data, although obtained in animal model, suggest their possible hazard for human health (i.e., hyperthermia and sensorimotor alterations). In particular, these novel psychoactive substances may have a negative impact in many daily activities, greatly increasing the risk factors for workplace accidents and traffic injuries. Copyright © 2017 John Wiley & Sons, Ltd.

Construction of Escherichia coli Strains for Conversion of Nitroacetophenones to ortho-Aminophenols

PubMed Central

Kadiyala, Venkateswarlu; Nadeau, Lloyd J.; Spain, Jim C.

2003-01-01

The predominant bacterial pathway for nitrobenzene (NB) degradation uses an NB nitroreductase and hydroxylaminobenzene (HAB) mutase to form the ring-fission substrate ortho-aminophenol. We tested the hypothesis that constructed strains might accumulate the aminophenols from nitroacetophenones and other nitroaromatic compounds. We constructed a recombinant plasmid carrying NB nitroreductase (nbzA) and HAB mutase A (habA) genes, both from Pseudomonas pseudoalcaligenes JS45, and expressed the enzymes in Escherichia coli JS995. IPTG (isopropyl-β-d-thiogalactopyranoside)-induced cells of strain JS995 rapidly and stoichiometrically converted NB to 2-aminophenol, 2-nitroacetophenone (2NAP) to 2-amino-3-hydroxyacetophenone (2AHAP), and 3-nitroacetophenone (3NAP) to 3-amino-2-hydroxyacetophenone (3AHAP). We constructed another recombinant plasmid containing the nitroreductase gene (nfs1) from Enterobacter cloacae and habA from strain JS45 and expressed the enzymes in E. coli JS996. Strain JS996 converted NB to 2-aminophenol, 2-nitrotoluene to 2-amino-3-methylphenol, 3-nitrotoluene to 2-amino-4-methylphenol, 4-nitrobiphenyl ether to 4-amino-5-phenoxyphenol, and 1-nitronaphthalene to 2-amino-1-naphthol. In larger-scale biotransformations catalyzed by strain JS995, 75% of the 2NAP transformed was converted to 2AHAP, whereas 3AHAP was produced stoichiometrically from 3NAP. The final yields of the aminophenols after extraction and recovery were >64%. The biocatalytic synthesis of ortho-aminophenols from nitroacetophenones suggests that strain JS995 may be useful in the biocatalytic production of a variety of substituted ortho-aminophenols from the corresponding nitroaromatic compounds.   PMID:14602609

Substitution effects on the absorption spectra of nitrophenolate isomers.

PubMed

Wanko, Marius; Houmøller, Jørgen; Støchkel, Kristian; Suhr Kirketerp, Maj-Britt; Petersen, Michael Åxman; Nielsen, Mogens Brøndsted; Nielsen, Steen Brøndsted; Rubio, Angel

2012-10-05

Charge-transfer excitations highly depend on the electronic coupling between the donor and acceptor groups. Nitrophenolates are simple examples of charge-transfer systems where the degree of coupling differs between ortho, meta and para isomers. Here we report the absorption spectra of the isolated anions in vacuo to avoid the complications of solvent effects. Gas-phase action spectroscopy was done with two different setups, an electrostatic ion storage ring and an accelerator mass spectrometer. The results are interpreted on the basis of CC2 quantum chemical calculations. We identified absorption maxima at 393, 532, and 399 nm for the para, meta, and ortho isomer, respectively, with the charge-transfer transition into the lowest excited singlet state. In the meta isomer, this π-π* transition is strongly redshifted and its oscillator strength reduced, which is related to the pronounced charge-transfer character, as a consequence of the topology of the conjugated π-system. Each isomer's different charge distribution in the ground state leads to a very different solvent shift, which in acetonitrile is bathochromic for the para and ortho, but hypsochromic for the meta isomer.

[Methodology for clinical research in Orthodontics, the assets of the beOrtho website].

PubMed

Ruiz, Martial; Thibult, François

2014-06-01

The rules applying to the "evidence-based" methodology strongly influenced the clinical research in orthodontics. However, the implementation of clinical studies requires rigour, important statistical and methodological knowledge, as well as a reliable environment in order to compile and store the data obtained from research. We developed the project "beOrtho.com" (based on orthodontic evidence) in order to fill up the gap between our desire to drive clinical research and the necessity of methodological rigour in the exploitation of its results. BeOrtho website was created to answer the issue of sample recruitment, data compilation and storage, while providing help for the methodological design of clinical studies. It allows the development and monitoring of clinical studies, as well as the creation of databases. On the other hand, we designed an evaluation grid for clinical studies which helps developing systematic reviews. In order to illustrate our point, we tested a research protocol evaluating the interest of the mandibular advancement in the framework of Class II treatment. © EDP Sciences, SFODF, 2014.

Covalent functionalization of graphene by azobenzene with molecular hydrogen bonds for long-term solar thermal storage

NASA Astrophysics Data System (ADS)

Feng, Yiyu; Liu, Hongpo; Luo, Wen; Liu, Enzuo; Zhao, Naiqin; Yoshino, Katsumi; Feng, Wei

2013-11-01

Reduced graphene oxide-azobenzene (RGO-AZO) hybrids were prepared via covalent functionalization for long-term solar thermal storage. Thermal barrier (ΔEa) of cis to tran reversion and thermal storage (ΔH) were improved by molecular hydrogen bonds (H-bonds) through ortho- or para-substitution of AZO. Intramolecular H-bonds thermally stabilized cis-ortho-AZO on RGO with a long-term half-life of 5400 h (ΔEa = 1.2 eV), which was much longer than that of RGO-para-AZO (116 h). RGO-para-AZO with one intermolecular H-bond showed a high density of thermal storage up to 269.8 kJ kg-1 compared with RGO-ortho-AZO (149.6 kJ kg-1) with multiple intra- and intermolecular H-bonds of AZO according to relaxed stable structures. Thermal storage in experiment was the same order magnitude to theoretical data based on ΔH calculated by density functional theory and packing density. Photoactive RGO-AZO hybrid can be developed for high-performance solar thermal storage by optimizing molecular H-bonds.

Synthesis and NMR Analysis of a Conformationally Controlled β-Turn Mimetic Torsion Balance.

PubMed

Lypson, Alyssa B; Wilcox, Craig S

2017-01-20

The molecular torsion balance concept was applied to a new conformationally controlled scaffold and synthesized to accurately evaluate pairwise amino acid interactions in an antiparallel β-sheet motif. The scaffold's core design combines (ortho-tolyl)amide and o,o,o'-trisubstituted biphenyl structural units to provide a geometry better-suited for intramolecular hydrogen bonding. Like the dibenzodiazocine hinge of the traditional torsion balance, the (ortho-tolyl)amide unit offers restricted rotation around an N-aryl bond. The resulting two-state folding model is a powerful template for measuring hydrogen bond stability between two competing sequences. The aim of this study was to improve the alignment between the amino acid sequences attached to the upper and lower aromatic rings in order to promote hydrogen bond formation at the correct distance and antiparallel orientation. Bromine substituents were introduced ortho to the upper side chains and compared to a control to test our hypothesis. Hydrogen bond formation has been identified between the NH amide proton of the upper side chain (proton donor) and glycine acetamide of the lower side chain (proton acceptor).

Covalent functionalization of graphene by azobenzene with molecular hydrogen bonds for long-term solar thermal storage

PubMed Central

Feng, Yiyu; Liu, Hongpo; Luo, Wen; Liu, Enzuo; Zhao, Naiqin; Yoshino, Katsumi; Feng, Wei

2013-01-01

Reduced graphene oxide-azobenzene (RGO-AZO) hybrids were prepared via covalent functionalization for long-term solar thermal storage. Thermal barrier (ΔEa) of cis to tran reversion and thermal storage (ΔH) were improved by molecular hydrogen bonds (H-bonds) through ortho- or para-substitution of AZO. Intramolecular H-bonds thermally stabilized cis-ortho-AZO on RGO with a long-term half-life of 5400 h (ΔEa = 1.2 eV), which was much longer than that of RGO-para-AZO (116 h). RGO-para-AZO with one intermolecular H-bond showed a high density of thermal storage up to 269.8 kJ kg−1 compared with RGO-ortho-AZO (149.6 kJ kg−1) with multiple intra- and intermolecular H-bonds of AZO according to relaxed stable structures. Thermal storage in experiment was the same order magnitude to theoretical data based on ΔH calculated by density functional theory and packing density. Photoactive RGO-AZO hybrid can be developed for high-performance solar thermal storage by optimizing molecular H-bonds. PMID:24247355

Solvation of carbonaceous molecules by para-H2 and ortho-D2 clusters. II. Fullerenes.

PubMed

Calvo, F; Yurtsever, E

2016-08-28

The coating of various fullerenes by para-hydrogen and ortho-deuterium molecules has been computationally studied as a function of the solvent amount. Rotationally averaged interaction potentials for structureless hydrogen molecules are employed to model their interaction with neutral or charged carbonaceous dopants containing between 20 and 240 atoms, occasionally comparing different fullerenes having the same size but different shapes. The solvation energy and the size of the first solvation shell obtained from path-integral molecular dynamics simulations at 2 K show only minor influence on the dopant charge and on the possible deuteration of the solvent, although the shell size is largest for ortho-D2 coating cationic fullerenes. Nontrivial finite size effects have been found with the shell size varying non-monotonically close to its completion limit. For fullerenes embedded in large hydrogen clusters, the shell size and solvation energy both follow linear scaling with the fullerene size. The shell sizes obtained for C60 (+) and C70 (+) are close to 49 and 51, respectively, and agree with mass spectrometry experiments.

Solvation of carbonaceous molecules by para-H2 and ortho-D2 clusters. II. Fullerenes

NASA Astrophysics Data System (ADS)

Calvo, F.; Yurtsever, E.

2016-08-01

The coating of various fullerenes by para-hydrogen and ortho-deuterium molecules has been computationally studied as a function of the solvent amount. Rotationally averaged interaction potentials for structureless hydrogen molecules are employed to model their interaction with neutral or charged carbonaceous dopants containing between 20 and 240 atoms, occasionally comparing different fullerenes having the same size but different shapes. The solvation energy and the size of the first solvation shell obtained from path-integral molecular dynamics simulations at 2 K show only minor influence on the dopant charge and on the possible deuteration of the solvent, although the shell size is largest for ortho-D2 coating cationic fullerenes. Nontrivial finite size effects have been found with the shell size varying non-monotonically close to its completion limit. For fullerenes embedded in large hydrogen clusters, the shell size and solvation energy both follow linear scaling with the fullerene size. The shell sizes obtained for C 60+ and C 70+ are close to 49 and 51, respectively, and agree with mass spectrometry experiments.

Shear bond strength of different retainer wires and bonding adhesives in consideration of the pretreatment process.

PubMed

Reicheneder, Claudia; Hofrichter, Bernd; Faltermeier, Andreas; Proff, Peter; Lippold, Carsten; Kirschneck, Christian

2014-11-28

We aimed to compare the shear bond strength (SBS) of three different retainer wires and three different bonding adhesives in consideration of the pretreatment process of enamel surface sandblasting. 400 extracted bovine incisors were divided into 10 groups of 20 paired specimens each. 10 specimens of each group were pretreated by enamel sandblasting. The retainer wires Bond-A-Braid™, GAC-Wildcat®-Twistflex and everStick®ORTHO were bonded to the teeth with the adhesives Transbond™-LR, Tetric-EvoFlow™ and Stick®FLOW and then debonded measuring the SBS. While sandblasting generally increased SBS for all tested combinations, the retainer wires bonded with Transbond™-LR showed the highest SBS both with and without prior sandblasting. Significantly lower SBS were found for Tetric-EvoFlow™ that were comparable to those for everStick®ORTHO. Pretreatment of enamel surfaces by sandblasting increased the SBS of all retainer-wires. Transbond™-LR showed the best results compared to Tetric-EvoFlow™ and everStick®ORTHO, while all combinations used provided sufficient bonding strengths for clinical use.

Covalent functionalization of graphene by azobenzene with molecular hydrogen bonds for long-term solar thermal storage.

PubMed

Feng, Yiyu; Liu, Hongpo; Luo, Wen; Liu, Enzuo; Zhao, Naiqin; Yoshino, Katsumi; Feng, Wei

2013-11-19

Reduced graphene oxide-azobenzene (RGO-AZO) hybrids were prepared via covalent functionalization for long-term solar thermal storage. Thermal barrier (ΔEa) of cis to tran reversion and thermal storage (ΔH) were improved by molecular hydrogen bonds (H-bonds) through ortho- or para-substitution of AZO. Intramolecular H-bonds thermally stabilized cis-ortho-AZO on RGO with a long-term half-life of 5400 h (ΔEa = 1.2 eV), which was much longer than that of RGO-para-AZO (116 h). RGO-para-AZO with one intermolecular H-bond showed a high density of thermal storage up to 269.8 kJ kg(-1) compared with RGO-ortho-AZO (149.6 kJ kg(-1)) with multiple intra- and intermolecular H-bonds of AZO according to relaxed stable structures. Thermal storage in experiment was the same order magnitude to theoretical data based on ΔH calculated by density functional theory and packing density. Photoactive RGO-AZO hybrid can be developed for high-performance solar thermal storage by optimizing molecular H-bonds.

Analysis of source data resolution on photogrammetric products quality of architectural object. (Polish Title: Analiza wpęywu rozdzielczości danych śródłowych na jakość produktów fotogrametrycznych obiektu architektury)

NASA Astrophysics Data System (ADS)

Markiewicz, J. S.; Kowalczyk, M.; Podlasiak, P.; Bakuła, K.; Zawieska, D.; Bujakiewicz, A.; Andrzejewska, E.

2013-12-01

Due to considerable development of the non - invasion measurement technologies, taking advantages from the distance measurement, the possibility of data acquisition increased and at the same time the measurement period has been reduced. This, by combination of close range laser scanning data and images, enabled the wider expansion of photogrammetric methods effectiveness in registration and analysis of cultural heritage objects. Mentioned integration allows acquisition of objects three - dimensional models and in addition digital image maps - true - ortho and vector products. The quality of photogrammetric products is defined by accuracy and the range of content, therefore by number and the minuteness of detail. That always depends on initial data geometrical resolution. The research results presented in the following paper concern the quality valuation of two products, image of true - ortho and vector data, created for selected parts of architectural object. Source data is represented by point collection i n cloud, acquired from close range laser scanning and photo images. Both data collections has been acquired with diversified resolutions. The exterior orientation of images and several versions of the true - ortho are based on numeric models of the object, acquired with specified resolutions. The comparison of these products gives the opportunity to rate the influence of initial data resolution on their quality (accuracy, information volume). Additional analysis will be performed on the base of vector product s comparison, acquired from monoplotting and true - ortho images. As a conclusion of experiment it was proved that geometric resolution has significant impact on the possibility of generation and on the accuracy of relative orientation TLS scans. If creation of high - resolution products is considered, scanning resolution of about 2 mm should be applied and in case of architecture details - 1 mm. It was also noted that scanning angle and object structure has significant influence on accuracy and completeness of the data. For creation of true - orthoimages for architecture purposes high - resolution ground - based images in geometry close to normal case are recommended to improve their quality. The use of grayscale true - orthoimages with values from scanner intensity is not advised. Presented research proved also that accuracy of manual and automated vectorisation results depend significantly on the resolution of the generated orthoimages (scans and images resolution) and mainly of blur effect and possible pixel size.

TU-H-BRC-01: A New Fabrication Method for Secondary Skin Collimation Using 3D Scanner and 3D Printer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jung, J; Potter, N; Suh, T

Purpose: Using secondary skin collimation (SSC) to protect the critical organ surrounding the tumors is always desirable for electron and/or ortho-voltage treatments. However, the time-consuming and labor-intensive fabrication processes of current method (manually fabricate the lead mask) restrict the general use of SSC. The aim of this study is to develop a new SSC fabrication method using 3D scanning and 3D printing technologies in order to largely decrease the human labor involvement and fabrication time, also improve the fabrication accuracy. Methods: First, the patient surface was scanned with a 3D scanner (Structure Sensor, Occipital, CO). The raw scan data wasmore » subsequently transferred to a 3D modeling software (Rhinoceros, Ver. 5.0, McNeel North America, Seattle, WA). The tumor contour was then digitized and shielding region was determined by clinicians in the same software. The corresponding SCC conformed to the skin surface was then automatically generated by the software with the proper shielding thickness. The shell of the SCC (with hollow inside) was consequently printed by a 3D printer (Lulzbot TAZ, Aleph Objects, CO) using plastic material. Finally, the hollow mold of SCC was filled up with a melted cerrobend alloy. Once the cerrobend alloy cooled down, the fabrication of SCC was accomplished. Results: The results indicated the proposed method can achieve a much shorter time on making a SCC compared with tradition fabrication method. The processes of making a skin contour model for patients have been eliminated with the new method. SCC created by the new method possessed better accuracy and better conformality to patient’s skin contours. Conclusion: In this study, we have demonstrated a new method for the SCC fabrication. It is anticipated that our method can be an alternative way to replace conventional manual-based methods for electron and/or ortho-voltage SCC fabrication. This research was supported by the Global Ph.D. Fellowship Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant No. 2015H1A2A1034071), Republic of Korea.« less

Georeferencing CAMS data: Polynomial rectification and beyond

NASA Astrophysics Data System (ADS)

Yang, Xinghe

The Calibrated Airborne Multispectral Scanner (CAMS) is a sensor used in the commercial remote sensing program at NASA Stennis Space Center. In geographic applications of the CAMS data, accurate geometric rectification is essential for the analysis of the remotely sensed data and for the integration of the data into Geographic Information Systems (GIS). The commonly used rectification techniques such as the polynomial transformation and ortho rectification have been very successful in the field of remote sensing and GIS for most remote sensing data such as Landsat imagery, SPOT imagery and aerial photos. However, due to the geometric nature of the airborne line scanner which has high spatial frequency distortions, the polynomial model and the ortho rectification technique in current commercial software packages such as Erdas Imagine are not adequate for obtaining sufficient geometric accuracy. In this research, the geometric nature, especially the major distortions, of the CAMS data has been described. An analytical step-by-step geometric preprocessing has been utilized to deal with the potential high frequency distortions of the CAMS data. A generic sensor-independent photogrammetric model has been developed for the ortho-rectification of the CAMS data. Three generalized kernel classes and directional elliptical basis have been formulated into a rectification model of summation of multisurface functions, which is a significant extension to the traditional radial basis functions. The preprocessing mechanism has been fully incorporated into the polynomial, the triangle-based finite element analysis as well as the summation of multisurface functions. While the multisurface functions and the finite element analysis have the characteristics of localization, piecewise logic has been applied to the polynomial and photogrammetric methods, which can produce significant accuracy improvement over the global approach. A software module has been implemented with full integration of data preprocessing and rectification techniques under Erdas Imagine development environment. The final root mean square (RMS) errors for the test CAMS data are about two pixels which are compatible with the random RMS errors existed in the reference map coordinates.

Landslide Mapping Using Imagery Acquired by a Fixed-Wing Uav

NASA Astrophysics Data System (ADS)

Rau, J. Y.; Jhan, J. P.; Lo, C. F.; Lin, Y. S.

2011-09-01

In Taiwan, the average annual rainfall is about 2,500 mm, about three times the world average. Hill slopes where are mostly under meta-stable conditions due to fragmented surface materials can easily be disturbed by heavy typhoon rainfall and/or earthquakes, resulting in landslides and debris flows. Thus, an efficient data acquisition and disaster surveying method is critical for decision making. Comparing with satellite and airplane, the unmanned aerial vehicle (UAV) is a portable and dynamic platform for data acquisition. In particularly when a small target area is required. In this study, a fixed-wing UAV that equipped with a consumer grade digital camera, i.e. Canon EOS 450D, a flight control computer, a Garmin GPS receiver and an attitude heading reference system (AHRS) are proposed. The adopted UAV has about two hours flight duration time with a flight control range of 20 km and has a payload of 3 kg, which is suitable for a medium scale mapping and surveying mission. In the paper, a test area with 21.3 km2 in size containing hundreds of landslides induced by Typhoon Morakot is used for landslides mapping. The flight height is around 1,400 meters and the ground sampling distance of the acquired imagery is about 17 cm. The aerial triangulation, ortho-image generation and mosaicking are applied to the acquired images in advance. An automatic landslides detection algorithm is proposed based on the object-based image analysis (OBIA) technique. The color ortho-image and a digital elevation model (DEM) are used. The ortho-images before and after typhoon are utilized to estimate new landslide regions. Experimental results show that the developed algorithm can achieve a producer's accuracy up to 91%, user's accuracy 84%, and a Kappa index of 0.87. It demonstrates the feasibility of the landslide detection algorithm and the applicability of a fixed-wing UAV for landslide mapping.

Direct observation and modelling of ordered hydrogen adsorption and catalyzed ortho-para conversion on ETS-10 titanosilicate material.

PubMed

Ricchiardi, Gabriele; Vitillo, Jenny G; Cocina, Donato; Gribov, Evgueni N; Zecchina, Adriano

2007-06-07

Hydrogen physisorption on porous high surface materials is investigated for the purpose of hydrogen storage and hydrogen separation, because of its simplicity and intrinsic reversibility. For these purposes, the understanding of the binding of dihydrogen to materials, of the structure of the adsorbed phase and of the ortho-para conversion during thermal and pressure cycles are crucial for the development of new hydrogen adsorbents. We report the direct observation by IR spectroscopic methods of structured hydrogen adsorption on a porous titanosilicate (ETS-10), with resolution of the kinetics of the ortho-para transition, and an interpretation of the structure of the adsorbed phase based on classical atomistic simulations. Distinct infrared signals of o- and p-H2 in different adsorbed states are measured, and the conversion of o- to p-H2 is monitored over a timescale of hours, indicating the presence of a catalyzed reaction. Hydrogen adsorption occurs in three different regimes characterized by well separated IR manifestations: at low pressures ordered 1:1 adducts with Na and K ions exposed in the channels of the material are formed, which gradually convert into ordered 2:1 adducts. Further addition of H2 occurs only through the formation of a disordered condensed phase. The binding enthalpy of the Na+-H2 1:1 adduct is of -8.7+/-0.1 kJ mol(-1), as measured spectroscopically. Modeling of the weak interaction of H2 with the materials requires an accurate force field with a precise description of both dispersion and electrostatics. A novel three body force field for molecular hydrogen is presented, based on the fitting of an accurate PES for the H2-H2 interaction to the experimental dipole polarizability and quadrupole moment. Molecular mechanics simulations of hydrogen adsorption at different coverages confirm the three regimes of adsorption and the structure of the adsorbed phase.

Consistent assignment of the vibrations of symmetric and asymmetric ortho-disubstituted benzenes

NASA Astrophysics Data System (ADS)

Tuttle, William D.; Gardner, Adrian M.; Andrejeva, Anna; Kemp, David J.; Wakefield, Jonathan C. A.; Wright, Timothy G.

2018-02-01

The form of molecular vibrations, and changes in these, give valuable insights into geometric and electronic structure upon electronic excitation or ionization, and within families of molecules. Here, we give a description of the phenyl-ring-localized vibrational modes of the ground (S0) electronic states of a wide range of ortho-disubstituted benzene molecules including both symmetrically- and asymmetrically-substituted cases. We conclude that the use of the commonly-used Wilson or Varsányi mode labels, which are based on the vibrational motions of benzene itself, is misleading and ambiguous. In addition, we also find the use of the Mi labels for monosubstituted benzenes [A.M. Gardner, T.G. Wright. J. Chem. Phys. 135 (2011) 114305], or the recently-suggested labels for para-disubstituted benzenes [A. Andrejeva, A.M. Gardner, W.D. Tuttle, T.G. Wright, J. Molec. Spectrosc. 321, 28 (2016)] are not appropriate. Instead, we label the modes consistently based upon the Mulliken (Herzberg) method for the modes of ortho-difluorobenzene (pDFB) under Cs symmetry, since we wish the labelling scheme to cover both symmetrically- and asymmetrically-substituted molecules. By studying the vibrational wavenumbers from the same force field while varying the mass of the substituent, we are able to identify the corresponding modes across a wide range of molecules and hence provide consistent assignments. We assign the vibrations of the following sets of molecules: the symmetric o-dihalobenzenes, o-xylene and catechol (o-dihydroxybenzene); and the asymmetric o-dihalobenzenes, o-halotoluenes, o-halophenols and o-cresol. In the symmetrically-substituted species, we find a pair of in-phase and out-of-phase carbon-substituent stretches, and this motion persists in asymmetrically-substituted molecules for heavier substituents. When at least one of the substituents is light, then we find that these evolve into localized carbon-substituent stretches.

Synthesis and animal studies of L-para-(/sup 18/F)-fluorophenyl-alanine as probe for in vivo cerebral protein synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coenen, H.H.; Bodsch, W.; Takahashi, K.

For the quantitation of cerebral protein synthesis in man by dynamic PET studies, fluorine-18 analogues seem superior to carbon-11 labeled substrates with respect to half-life and interference of amino acid metabolism giving rise to reutilization. Therefore, para- and ortho- /sup 18/F- fluorophenylalanine were prepared to study its metabolism in neuronal tissue. A labeling method was developed using direct electrophilic fluorination with (/sup 18/F)-F/sub 2/. Reaction of fluorine with L-phenylalanine in CF/sub 3/CO/sub 2/H at O/sup 0/C yielded 12-15% of ortho- and 6-8% of para-/sup 18/F-flurorophenylalanine. Isolation of the isomers was achieved by means of repeated RP-HPLC. The specific activity wasmore » about 2 Ci/mmole at 100 min after EOB. Both compounds showed a pharmacokinetic behaviour in mice after i.v. injection typical for natural amino acids. The accumulation in mice brain tissue reaches a plateau value after 5 min with 1.7% of the injected dose/g for para (2.5% in gerbils) and 2% for ortho. In a pilot study, about 1 mCi of p-/sup 18/F-phenylalanine was coinjected with 0.3 mCi (100 Ci/mmole) /sup 3/H-phenylalanine into the femoral vein of halothane-anesthetized Mongolian gerbils. The distribution obtained autoradiographyically in 20 ..mu..m sections of the frozen brain of an animal after 45 min revealed a similar pattern for both compounds indicating protein synthesis. In a parallel study 3-/sup 14/C-para-fluorophenylalanine was used to determine the chemical form of radioactivity in brain by means of HPLC. After 45 minutes, 7% of total brain activity was found as free amino acid and 60% was incorporated into proteins.« less

TBDPS and Br-TBDPS Protecting Groups as Efficient Aryl Group Donors in Pd-Catalyzed Arylation of Phenols and Anilines

PubMed Central

Huang, Chunhui; Gevorgyan, Vladimir

2009-01-01

It was shown that the TBDPS protecting group can serve as an efficient phenyl group donor for o-bromophenols via the Pd-catalyzed C—H arylation, followed by a routine TBAF deprotection of the forming silacycles. Employment of the newly designed Br-TBDPS protecting group in the same sequence allows for a facile introduction of a phenyl group in the ortho-position of phenols and anilines. Alternatively, switching desilylation to oxidation at the last step allows converting the forming silacycles into valuable ortho-biphenols. PMID:19722665

Michael Additions of Highly Basic Enolates to ortho-Quinone Methides

PubMed Central

Lewis, Robert S.; Garza, Christopher J.; Dang, Ann T.; Pedro, Te Kie A.; Chain, William J.

2015-01-01

A protocol by which ketone or ester enolates and ortho-quinone methides (o-QMs) are generated in situ in a single reaction flask from silylated precursors under the action of anhydrous fluoride is reported. The reaction partners are joined to give a variety of β-(2-hydroxyphenyl)-carbonyl compounds in 32–94% yield in a single laboratory operation. The intermediacy of o-QMs is supported by control experiments utilizing enolate precursors and conventional alkyl halides as competitive alkylating agents and the isolation of 1,5-dicarbonyl products resulting from conjugate additions that do not restore the aromatic system. PMID:25906358

Spectrum of the Reductive Dehalogenation Activity of Desulfitobacterium frappieri PCP-1

PubMed Central

Dennie, D.; Gladu, I.; Lépine, F.; Villemur, R.; Bisaillon, J.-G.; Beaudet, R.

1998-01-01

Desulfitobacterium frappieri PCP-1 was induced for ortho- and para-dechlorinating activities by different chlorophenols. Dehalogenation rates ranging from 25 to 1,158 nmol/min/mg of cell protein were observed according to the chlorophenol tested and the position of the chlorine removed. D. frappieri shows a broad substrate specificity; in addition to tetrachloroethylene and pentachloropyridine, strain PCP-1 can dehalogenate at ortho, meta, and para positions a large variety of aromatic molecules with substituted hydroxyl or amino groups. Reactions of O demethylation and reduction of nitro to amino substituents on aromatic molecules were also observed. PMID:9797330

Pressure-enhanced ortho-para conversion in solid hydrogen up to 58 GPa

PubMed Central

Eggert, Jon H.; Karmon, Eran; Hemley, Russell J.; Mao, Ho-kwang; Goncharov, Alexander F.

1999-01-01

We measured the ortho-para conversion rate in solid hydrogen by using Raman scattering in a diamond-anvil cell, extending previous measurements by a factor of 60 in pressure. We confirm previous experiments that suggested a decrease in the conversion rate above about 0.5 GPa. We observe a distinct minimum at 3 GPa followed by a drastic increase in the conversion rate to our maximum pressure of 58 GPa. This pressure enhancement of conversion is not predicted by previous theoretical treatments and must be due to a new conversion pathway. PMID:10535910

The Reactions of Recoil Tritium with Anilides (in Japanese)

DOE Office of Scientific and Technical Information (OSTI.GOV)

OKAMOTO, Jiro; TSUCHIHASHI, Gen-ichi

1961-01-01

The distribution of tritium in some tritiated anilides (acetanilide, propionanilide, n-butylanilide, iso-butylanilide) which were produced by irradiation of mixed powder of anilides and lithium carbonate, were investigated. The tritium contents of the ortho-, meta-, and para-positions in the anilides were obtained by the activity measurement of some derivatives. The reactivities of ortho-position for tritium decreases in the order acetanilide, propionanilide, nbutylanilide, iso-butylanilide, perhaps because of steric interference of alkyl groups. The contents of incorporated tritium in alkyl groups were 13.2%, 31.7%, 31.1%, and 45.4%, for acetanilide, propionanilide, n-butylanilide, iso- butylanilide, respectively.

Comparison of myopia control between toric and spherical periphery design orthokeratology in myopic children with moderate-to-high corneal astigmatism.

PubMed

Zhang, Yu; Chen, Yue-Guo

2018-01-01

To compare clinical results between toric and spherical periphery design orthokeratology (ortho-k) in myopic children with moderate-to-high corneal astigmatism. This retrospective study enrolled 62 eyes of 62 subjects using toric ortho-k lenses. These subjects were assigned to the toric group. Based on the one-to-one match principle (same age, proximate spherical equivalence and corneal astigmatism), 62 eyes of 62 subjects were enrolled and included in the spherical group. At one-year follow-up visit, visual acuity, corneal astigmatism, treatment zone decentration, axial elongation and adverse reaction were compared between these two groups. At the one-year visit, corneal astigmatism was significantly lower in the toric group (1.22±0.76 D) than in the spherical group (2.05±0.85 D) ( P =0.012). The mean magnitude of the treatment zone decentration was 0.62±0.42 mm in the toric group and 1.07±0.40 mm in the spherical group ( P =0.004). Axial elongation was significantly slower in the toric group (0.04±0.13 mm) than in the spherical group (0.09±0.13 mm) ( P =0.001). The one-year axial elongation was significantly correlated with initial age ( r =-0.487, P <0.001) and periphery design of ortho-k lens ( r =0.315, P <0.001). The incidence of corneal staining was lower in the toric group (8.1%) than in the spherical group (19.4%) ( P <0.001). Toric periphery design ortho-k lenses may provide lower corneal astigmatism, better centration, slower axial elongation and lower incidence of corneal staining in myopic children with moderate-to-high corneal astigmatism.

Candidate Water Vapor Lines to Locate the H2O Snowline through High-dispersion Spectroscopic Observations. III. Submillimeter H2 16O and H2 18O Lines

NASA Astrophysics Data System (ADS)

Notsu, Shota; Nomura, Hideko; Walsh, Catherine; Honda, Mitsuhiko; Hirota, Tomoya; Akiyama, Eiji; Millar, T. J.

2018-03-01

In this paper, we extend the results presented in our former papers on using ortho-{{{H}}}2{}16{{O}} line profiles to constrain the location of the H2O snowline in T Tauri and Herbig Ae disks, to include submillimeter para-{{{H}}}2{}16{{O}} and ortho- and para-{{{H}}}2{}18{{O}} lines. Since the number densities of the ortho- and para-{{{H}}}2{}18{{O}} molecules are about 560 times smaller than their 16O analogs, they trace deeper into the disk than the ortho-{{{H}}}2{}16{{O}} lines (down to z = 0, i.e., the midplane). Thus these {{{H}}}2{}18{{O}} lines are potentially better probes of the position of the H2O snowline at the disk midplane, depending on the dust optical depth. The values of the Einstein A coefficients of submillimeter candidate water lines tend to be lower (typically <10‑4 s‑1) than infrared candidate water lines. Thus in the submillimeter candidate water line cases, the local intensity from the outer optically thin region in the disk is around 104 times smaller than that in the infrared candidate water line cases. Therefore, in the submillimeter lines, especially {{{H}}}2{}18{{O}} and para-{{{H}}}2{}16{{O}} lines with relatively lower upper state energies (∼a few 100 K) can also locate the position of the H2O snowline. We also investigate the possibility of future observations with ALMA to identify the position of the water snowline. There are several candidate water lines that trace the hot water gas inside the H2O snowline in ALMA Bands 5–10.

Role of Tyrosine Isomers in Acute and Chronic Diseases Leading to Oxidative Stress - A Review.

PubMed

Molnár, Gergő A; Kun, Szilárd; Sélley, Eszter; Kertész, Melinda; Szélig, Lívia; Csontos, Csaba; Böddi, Katalin; Bogár, Lajos; Miseta, Attila; Wittmann, István

2016-01-01

Oxidative stress plays a major role in the pathogenesis of a variety of acute and chronic diseases. Measurement of the oxidative stress-related end products may be performed, e.g. that of structural isomers of the physiological para-tyrosine, namely meta- and ortho-tyrosine, that are oxidized derivatives of phenylalanine. Recent data suggest that in sepsis, serum level of meta-tyrosine increases, which peaks on the 2(nd) and 3(rd) days (p<0.05 vs. controls), and the kinetics follows the intensity of the systemic inflammation correlating with serum procalcitonin levels. In a similar study subset, urinary meta-tyrosine excretion correlated with both need of daily insulin dose and the insulin-glucose product in non-diabetic septic cases (p<0.01 for both). Using linear regression model, meta-tyrosine excretion, urinary meta-tyrosine/para-tyrosine, urinary ortho-tyrosine/para-tyrosine and urinary (meta- + orthotyrosine)/ para-tyrosine proved to be markers of carbohydrate homeostasis. In a chronic rodent model, we tried to compensate the abnormal tyrosine isomers using para-tyrosine, the physiological amino acid. Rats were fed a standard high cholesterol-diet, and were given para-tyrosine or vehicle orally. High-cholesterol feeding lead to a significant increase in aortic wall meta-tyrosine content and a decreased vasorelaxation of the aorta to insulin and the glucagon-like peptide-1 analogue, liraglutide, that both could be prevented by administration of para-tyrosine. Concluding, these data suggest that meta- and ortho-tyrosine are potential markers of oxidative stress in acute diseases related to oxidative stress, and may also interfere with insulin action in septic humans. Competition of meta- and ortho-tyrosine by supplementation of para-tyrosine may exert a protective role in oxidative stress-related diseases.

Ultramap: the all in One Photogrammetric Solution

NASA Astrophysics Data System (ADS)

Wiechert, A.; Gruber, M.; Karner, K.

2012-07-01

This paper describes in detail the dense matcher developed since years by Vexcel Imaging in Graz for Microsoft's Bing Maps project. This dense matcher was exclusively developed for and used by Microsoft for the production of the 3D city models of Virtual Earth. It will now be made available to the public with the UltraMap software release mid-2012. That represents a revolutionary step in digital photogrammetry. The dense matcher generates digital surface models (DSM) and digital terrain models (DTM) automatically out of a set of overlapping UltraCam images. The models have an outstanding point density of several hundred points per square meter and sub-pixel accuracy and are generated automatically. The dense matcher consists of two steps. The first step rectifies overlapping image areas to speed up the dense image matching process. This rectification step ensures a very efficient processing and detects occluded areas by applying a back-matching step. In this dense image matching process a cost function consisting of a matching score as well as a smoothness term is minimized. In the second step the resulting range image patches are fused into a DSM by optimizing a global cost function. The whole process is optimized for multi-core CPUs and optionally uses GPUs if available. UltraMap 3.0 features also an additional step which is presented in this paper, a complete automated true-ortho and ortho workflow. For this, the UltraCam images are combined with the DSM or DTM in an automated rectification step and that results in high quality true-ortho or ortho images as a result of a highly automated workflow. The paper presents the new workflow and first results.

Structural basis for regioisomerization in the alkali-metal-mediated zincation (AMMZn) of trifluoromethyl benzene by isolation of kinetic and thermodynamic intermediates.

PubMed

Armstrong, David R; Blair, Victoria L; Clegg, William; Dale, Sophie H; Garcia-Alvarez, Joaquin; Honeyman, Gordon W; Hevia, Eva; Mulvey, Robert E; Russo, Luca

2010-07-14

Performed with a desire to advance knowledge of the structures and mechanisms governing alkali-metal-mediated zincation, this study monitors the reaction between the TMP-dialkylzincate reagent [(TMEDA)Na(TMP)((t)Bu)Zn((t)Bu)] 1 and trifluoromethyl benzene C(6)H(5)CF(3) 2. A complicated mixture of products is observed at room temperature. X-ray crystallography has identified two of these products as ortho- and meta-regioisomers of heterotrianionic [(TMEDA)Na(TMP)(C(6)H(4)-CF(3))Zn((t)Bu)], 3-ortho and 3-meta, respectively. Multinuclear NMR data of the bulk crystalline product confirm the presence of these two regioisomers as well as a third isomer, 3-para, in a respective ratio of 20:11:1, and an additional product 4, which also exhibits ortho-zincation of the aryl substrate. Repeating the reaction at 0 degrees C gave exclusively 4, which was crystallographically characterized as [{(TMEDA)(2)Na}(+){Zn(C(6)H(4)-CF(3))((t)Bu)(2)}(-)]. Mimicking the original room-temperature reaction, this kinetic product was subsequently reacted with TMP(H) to afford a complicated mixture of products, including significantly the three regioisomers of 3. Surprisingly, 4 adopts a solvent-separated ion pair arrangement in contrast to the contacted ion variants of 3-ortho and 3-meta. Aided by DFT calculations on model systems, discussion focuses on the different basicities, amido or alkyl, and steps, exhibited in these reactions, and how the structures and bonding within these isolated key metallic intermediates (prior to any electrophilic interception step), specifically the interactions involving the alkali metal, influence the regioselectivity of the Zn-H exchange process.

Prognostic value of the Ortho Vitros cardiac troponin I assay in patients with symptoms of myocardial ischemia. Risk stratification using European Society of Cardiology/American College of Cardiology recommended cutoff values.

PubMed

Apple, Fred S; Murakami, MaryAnn M; Quist, Heidi H; Pearce, Lesly A; Wieczorek, Stacey; Wu, Alan H B

2003-07-01

We evaluated the risk assessment value of a commercial cardiac troponin (cTn; Ortho Vitros ECi, Ortho-Clinical Diagnostics, Raritan, NJ) I assay in patients with symptoms of myocardial ischemia suggestive of acute coronary syndrome and compared findings with those for a commercial cTnT assay in the same population. The cTn levels were measured by both assays in plasma samples from 273 patients during 24 hours after admission. Baseline and maximum concentrations were used for risk stratification; cutoffs were the 99th percentile and 10% coefficient of variation. End points were all-cause death and cardiac events within 60 days. Relative risks (RRs) were estimated using Cox proportional hazards regression models and Kaplan-Meier curves. RRs of cardiac events and death were significantly higher with increased baseline and maximum concentrations using either cTnI cutoff. The respective mortality rates for baseline cTnI of more than 0.08 microgram/L vs 0.08 microgram/L or less were 17.4% vs 2.9% (P = .001); cardiac event rates were 11.5% vs 3.6% (P = .03). Exclusion of patients with ST-segment elevation had no significant effect on rates for either assay. Mortality was higher in the intermediate (0.09-0.2 microgram/L) than in the low (< or = 0.08 microgram/L) group for cTnI, with directionally similar results for cTnT. Our findings validate the Ortho cTnI assay as a risk stratification biomarker in patients with symptoms of myocardial ischemia.

Ortho-para interconversion in cation-water complexes: The case of V + (H 2 O) and Nb + (H 2 O) clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, T. B.; Miliordos, E.; Carnegie, P. D.

Vanadium and niobium cation-water complexes, V+(H2O) and Nb+(H2O), are produced by laser vaporization in a pulsed supersonic expansion, mass selected in a time-of-flight spectrometer, and studied with infrared photodissociation spectroscopy using rare gas atom (Ar, Ne) complex predissociation. The vibrational bands measured in the O–H stretching region contain K-type rotational sub-band structure, which provides insight into the structures of these complexes. However, rotational sub-bands do not exhibit the simple patterns seen previously for other metal ion-water complexes. The A rotational constants are smaller than expected and the normal 1:3 intensity ratios for K = even:odd levels for independent ortho:para nuclearmore » spin states are missing for some complexes. We relied on highly correlated internally contracted Multi-Reference Configuration Interaction (icMRCI) and Coupled Cluster [CCSD(T)] electronic structure calculations of those complexes with and without the rare gas atoms to investigate these anomalies. Rare gas atoms were found to bind via asymmetric motifs to the hydrated complexes undergoing large amplitude motions that vibrationally average to quasi-C2v symmetry with significant probability off the C2 axis, thus explaining the reduced A values. Both vanadium and iobium cations exhibit unusually strong nuclear spin coupling to the hydrogen atoms of water, the values of which vary with their electronic state. This catalyzes ortho-para interconversion in some complexes and explains the rotational patterns. The rate of ortho-para relaxation in the equilibrated complexes must therefore be greater than the collisional cooling rate in the supersonic expansion (about 106 sec-1).« less

Anion photoelectron spectroscopy of deprotonated ortho-, meta-, and para-methylphenol

NASA Astrophysics Data System (ADS)

Nelson, Daniel J.; Gichuhi, Wilson K.; Miller, Elisa M.; Lehman, Julia H.; Lineberger, W. Carl

2017-02-01

The anion photoelectron spectra of ortho-, meta-, and para-methylphenoxide, as well as methyl deprotonated meta-methylphenol, were measured. Using the Slow Electron Velocity Map Imaging technique, the Electron Affinities (EAs) of the o-, m-, and p-methylphenoxyl radicals were measured as follows: 2.1991±0.0014, 2.2177±0.0014, and 2.1199±0.0014 eV, respectively. The EA of m-methylenephenol was also obtained, 1.024±0.008 eV. In all four cases, the dominant vibrational progressions observed are due to several ring distortion vibrational normal modes that were activated upon photodetachment, leading to vibrational progressions spaced by ˜500 cm-1. Using the methylphenol O-H bond dissociation energies reported by King et al. and revised by Karsili et al., a thermodynamic cycle was constructed and the acidities of the methylphenol isomers were determined as follows: Δa c i dH298K 0=348.39 ±0.25 , 348.82±0.25, 350.08±0.25, and 349.60±0.25 kcal/mol for cis-ortho-, trans-ortho-, m-, and p-methylphenol, respectively. The excitation energies for the ground doublet state to the lowest excited doublet state electronic transition in o-, m-, and p-methylphenoxyl were also measured as follows: 1.029±0.009, 0.962±0.002, and 1.029±0.009 eV, respectively. In the photoelectron spectra of the neutral excited states, C-O stretching modes were excited in addition to ring distortion modes. Electron autodetachment was observed in the cases of both m- and p-methylphenoxide, with the para isomer showing a lower photon energy onset for this phenomenon.

Ortho-para interconversion in cation-water complexes: The case of V+(H2O) and Nb+(H2O) clusters.

PubMed

Ward, T B; Miliordos, E; Carnegie, P D; Xantheas, S S; Duncan, M A

2017-06-14

Vanadium and niobium cation-water complexes, V + (H 2 O) and Nb + (H 2 O), are produced by laser vaporization in a pulsed supersonic expansion, mass selected in a time-of-flight spectrometer, and studied with infrared photodissociation spectroscopy using rare gas atom (Ar, Ne) complex predissociation. The vibrational bands measured in the O-H stretching region contain K-type rotational sub-band structure, which provides insight into the structures of these complexes. However, rotational sub-bands do not exhibit the simple patterns seen previously for other metal ion-water complexes. The A rotational constants are smaller than expected and the normal 3:1 intensity ratios for K = odd:even levels for independent ortho:para nuclear spin states are missing for some complexes. We relied on highly correlated internally contracted multi-reference configuration interaction and Coupled Cluster [CCSD(T)] electronic structure calculations of those complexes with and without the rare gas atoms to investigate these anomalies. Rare gas atoms were found to bind via asymmetric motifs to the hydrated complexes undergoing large amplitude motions that vibrationally average to the quasi-C 2v symmetry with a significant probability off the C 2 axis, thus explaining the reduced A values. Both vanadium and niobium cations exhibit unusually strong nuclear spin coupling to the hydrogen atoms of water, the values of which vary with their electronic state. This catalyzes ortho-para interconversion in some complexes and explains the rotational patterns. The rate of ortho-para relaxation in the equilibrated complexes must therefore be greater than the collisional cooling rate in the supersonic expansion (about 10 6 s -1 ).

Ortho-para interconversion in cation-water complexes: The case of V+(H2O) and Nb+(H2O) clusters

NASA Astrophysics Data System (ADS)

Ward, T. B.; Miliordos, E.; Carnegie, P. D.; Xantheas, S. S.; Duncan, M. A.

2017-06-01

Vanadium and niobium cation-water complexes, V+(H2O) and Nb+(H2O), are produced by laser vaporization in a pulsed supersonic expansion, mass selected in a time-of-flight spectrometer, and studied with infrared photodissociation spectroscopy using rare gas atom (Ar, Ne) complex predissociation. The vibrational bands measured in the O-H stretching region contain K-type rotational sub-band structure, which provides insight into the structures of these complexes. However, rotational sub-bands do not exhibit the simple patterns seen previously for other metal ion-water complexes. The A rotational constants are smaller than expected and the normal 3:1 intensity ratios for K = odd:even levels for independent ortho:para nuclear spin states are missing for some complexes. We relied on highly correlated internally contracted multi-reference configuration interaction and Coupled Cluster [CCSD(T)] electronic structure calculations of those complexes with and without the rare gas atoms to investigate these anomalies. Rare gas atoms were found to bind via asymmetric motifs to the hydrated complexes undergoing large amplitude motions that vibrationally average to the quasi-C2v symmetry with a significant probability off the C2 axis, thus explaining the reduced A values. Both vanadium and niobium cations exhibit unusually strong nuclear spin coupling to the hydrogen atoms of water, the values of which vary with their electronic state. This catalyzes ortho-para interconversion in some complexes and explains the rotational patterns. The rate of ortho-para relaxation in the equilibrated complexes must therefore be greater than the collisional cooling rate in the supersonic expansion (about 106 s-1).

Low-energy collision-induced fragmentation of negative ions derived from ortho-, meta-, and para-hydroxyphenyl carbaldehydes, ketones, and related compounds.

PubMed

Attygalle, Athula B; Ruzicka, Josef; Varughese, Deepu; Bialecki, Jason B; Jafri, Sayed

2007-09-01

Collision-induced dissociation (CID) mass spectra of anions derived from several hydroxyphenyl carbaldehydes and ketones were recorded and mechanistically rationalized. For example, the spectrum of m/z 121 ion of deprotonated ortho-hydroxybenzaldehyde shows an intense peak at m/z 93 for a loss of carbon monoxide attributable to an ortho-effect mediated by a charge-directed heterolytic fragmentation mechanism. In contrast, the m/z 121 ion derived from meta and para isomers undergoes a charge-remote homolytic cleavage to eliminate an *H and form a distonic anion radical, which eventually loses CO to produce a peak at m/z 92. In fact, for the para isomer, this two-step homolytic mechanism is the most dominant fragmentation pathway. The spectrum of the meta isomer on the other hand, shows two predominant peaks at m/z 92 and 93 representing both homolytic and heterolytic fragmentations, respectively. (18)O-isotope-labeling studies confirmed that the oxygen in the CO molecule that is eliminated from the anion of meta-hydroxybenzaldehyde originates from either the aldehydic or the phenolic group. In contrast, anions of ortho-hydroxybenzaldehyde and 2-hydroxy-1-naphthaldehyde, both of which show two consecutive CO eliminations, specifically lose the carbonyl oxygen first, followed by that of the phenolic group. Anions from 2-hydroxyphenyl alkyl ketones lose a ketene by a hydrogen transfer predominantly from the alpha position. Interestingly, a very significant charge-remote 1,4-elimination of a H(2) molecule was observed from the anion derived from 2,4-dihydroxybenzaldehyde. For this mechanism to operate, a labile hydrogen atom should be available on the hydroxyl group adjacent to the carbaldehyde functionality.

Positional effects of second-sphere amide pendants on electrochemical CO2 reduction catalyzed by iron porphyrins† †Electronic supplementary information (ESI) available: Procedures for synthetic, spectroscopic, and electrochemical experiments. CCDC 1582750. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc04682k

PubMed Central

Nichols, Eva M.; Derrick, Jeffrey S.; Nistanaki, Sepand K.; Smith, Peter T.

2018-01-01

The development of catalysts for electrochemical reduction of carbon dioxide offers an attractive approach to transforming this greenhouse gas into value-added carbon products with sustainable energy input. Inspired by natural bioinorganic systems that feature precisely positioned hydrogen-bond donors in the secondary coordination sphere to direct chemical transformations occurring at redox-active metal centers, we now report the design, synthesis, and characterization of a series of iron tetraphenylporphyrin (Fe-TPP) derivatives bearing amide pendants at various positions at the periphery of the metal core. Proper positioning of the amide pendants greatly affects the electrocatalytic activity for carbon dioxide reduction to carbon monoxide. In particular, derivatives bearing proximal and distal amide pendants on the ortho position of the phenyl ring exhibit significantly larger turnover frequencies (TOF) compared to the analogous para-functionalized amide isomers or unfunctionalized Fe-TPP. Analysis of TOF as a function of catalyst standard reduction potential enables first-sphere electronic effects to be disentangled from second-sphere through-space interactions, suggesting that the ortho-functionalized porphyrins can utilize the latter second-sphere property to promote CO2 reduction. Indeed, the distally-functionalized ortho-amide isomer shows a significantly larger through-space interaction than its proximal ortho-amide analogue. These data establish that proper positioning of secondary coordination sphere groups is an effective design element for breaking electronic scaling relationships that are often observed in electrochemical CO2 reduction. PMID:29732079

Alkyne Benzannulation Reactions for the Synthesis of Novel Aromatic Architectures.

PubMed

Hein, Samuel J; Lehnherr, Dan; Arslan, Hasan; J Uribe-Romo, Fernando; Dichtel, William R

2017-11-21

Aromatic compounds and polymers are integrated into organic field effect transistors, light-emitting diodes, photovoltaic devices, and redox-flow batteries. These compounds and materials feature increasingly complex designs, and substituents influence energy levels, bandgaps, solution conformation, and crystal packing, all of which impact performance. However, many polycyclic aromatic hydrocarbons of interest are difficult to prepare because their substitution patterns lie outside the scope of current synthetic methods, as strategies for functionalizing benzene are often unselective when applied to naphthalene or larger systems. For example, cross-coupling and nucleophilic aromatic substitution reactions rely on prefunctionalized arenes, and even directed metalation methods most often modify positions near Lewis basic sites. Similarly, electrophilic aromatic substitutions access single regioisomers under substrate control. Cycloadditions provide a convergent route to densely functionalized aromatic compounds that compliment the above methods. After surveying cycloaddition reactions that might be used to modify the conjugated backbone of poly(phenylene ethynylene)s, we discovered that the Asao-Yamamoto benzannulation reaction is notably efficient. Although this reaction had been reported a decade earlier, its scope and usefulness for synthesizing complex aromatic systems had been under-recognized. This benzannulation reaction combines substituted 2-(phenylethynyl)benzaldehydes and substituted alkynes to form 2,3-substituted naphthalenes. The reaction tolerates a variety of sterically congested alkynes, making it well-suited for accessing poly- and oligo(ortho-arylene)s and contorted hexabenzocoronenes. In many cases in which asymmetric benzaldehyde and alkyne cycloaddition partners are used, the reaction is regiospecific based on the electronic character of the alkyne substrate. Recognizing these desirable features, we broadened the substrate scope to include silyl- and halogen-substituted alkynes. Through a combined experimental and computational approach, we have elucidated mechanistic insight and key principles that govern the regioselectivity outcome of the benzannulation of structurally diverse alkynes. We have applied these methods to prepare sterically hindered, shape-persistent aromatic systems, heterocyclic aromatic compounds, functionalized 2-aryne precursors, polyheterohalogenated naphthalenes, ortho-arylene foldamers, and graphene nanoribbons. As a result of these new synthetic avenues, aromatic structures with interesting properties were uncovered such as ambipolar charge transport in field effect transistors based on our graphene nanoribbons, conformational aspects of ortho-arylene architectures resulting from intramolecular π-stacking, and modulation of frontier molecular orbitals via protonation of heteroatom containing aromatic systems. Given the availability of many substituted 2-(phenylethynyl)benzaldehydes and the regioselectivity of the benzannulation reaction, naphthalenes can be prepared with control of the substitution pattern at seven of the eight substitutable positions. Researchers in a range of fields are likely to benefit directly from newly accessible molecular and polymeric systems derived from polyfunctionalized naphthalenes.

Directed amination of non-acidic arene C-H bonds by a copper-silver catalytic system.

PubMed

Tran, Ly Dieu; Roane, James; Daugulis, Olafs

2013-06-03

Amine meets arene: A method for direct amination of β-C(sp(2))-H bonds of benzoic acid derivatives and γ-C(sp(2))-H bonds of benzylamine derivatives has been developed. The reaction is catalyzed by Cu(OAc)2 and a Ag2CO3 cocatalyst, and shows high generality and functional-group tolerance, as well as providing a straightforward means for the preparation of ortho-aminobenzoic acid derivatives. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In-depth survey report: control technology assessment of unit operations employed in oral-contraceptive tablet-making operations at Ortho Pharmaceutical Corporation, Raritan, New Jersey, June 13-17, 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anastas, M.Y.; Caplan, P.E.; Froehlich, P.A.

An on-site visit was made to the Ortho Pharmaceutical Corporation (OPC), Raritan, New Jersey to evaluate methods of controlling exposure to hazardous materials during the manufacturing of medications. OPC produced oral-contraceptive tablets containing norethindrone (NOR), mestranol, and ethynylestradiol (EE). Ventilation was an important engineering control at this site. Other engineering controls included the isolation of work procedures and automation of work practices for weighing ingredients, granulation of substances, tableting, and packaging. Area samples were taken for air monitoring of steroid concentration levels in each manufacturing area. Access to the work areas was only through the locker rooms. Samples taken inmore » the locker rooms revealed no detectable contaminant levels. Workers performing high risk activities wore air supplied vinyl suits and disposable rubber gloves. The vinyl suits had overshoes attached. For moderate risk activities the workers wore a disposable suit, rubber gloves and shoe covers. Appropriate respirators were provided. Workers in low risk activities wore disposable rubber gloves and appropriate respirators. Sampling indicated that processing workers experienced breathing-zone levels outside their vinyl suits of 16.40 and 0.36 micrograms/cubic meter of NOR and EE, respectively.« less

Radical-scavenging activity and cytotoxicity of p-methoxyphenol and p-cresol dimers.

PubMed

Kadoma, Yoshinori; Murakami, Yukio; Ogiwara, Takako; Machino, Mamoru; Yokoe, Ichiro; Fujisawa, Seiichiro

2010-02-26

Compoundswith two phenolic OH groups like curcumin possess efficient antioxidant and anti-inflammatory activity. We synthesized p-cresol dimer (2,2'-dihydroxy-5,5'-dimethylbiphenol, 2a) and p-methoxyphenol dimer (2,2'-dihydroxy-5,5'-dimethoxybiphenol, 2b) by ortho-ortho coupling reactions of the parent monomers, p-cresol (1a) and p-methoxyphenol (1b), respectively. Their antioxidant activity was determined using the induction period method, and their cytotoxicity towards RAW 264.7 cells was also investigated using a cell counting kit. The stoichiometric factors n (number of free radicals trapped by one mole of antioxidant moiety) for 2a and 2b were 3 and 2.8, respectively, being greater than those for 1a and 1b. The ratio of the rate constant of inhibition to that of propagation (k(inh)/k(p)) for 2a and 2b was similar to that for 2-t-butyl-4-methoxyphenol (BHA), a conventional food antioxidant. The 50% inhibitory dose (ID50) declined in the order 1b > 1a > 2b > 2a > BHA. The cytotoxicity for 2a and 2b was significantly greater than that for the parent monomers (p < 0.001), but smaller than that for BHA (p < 0.01). Compounds 2a and 2b may be useful as food antioxidants.

Study of DT-diaphorase in pigment-producing cells.

PubMed

Smit, N P; Hoogduijn, M J; Riley, P A; Pavel, S

1999-11-01

DT-diaphorase is an FAD-containing enzyme capable of a two-electron reduction of ortho- and paraquinones. Nicotinamide coenzymes (NADH + H+ and NADPH + H+) serve as hydrogen sources in these reactions. The role of DT-diaphorase has been thoroughly investigated in situations when the enzyme is able to reduce exogenous and endogenous quinones, hence protecting the cells against these reactive intermediates. The enzyme has also been studied in connection with its ability to activate some quinoid cytostatics. It is surprising that DT-diaphorase has never been investigated in pigment-producing cells that are known to generate considerable amounts of ortho-quinones. Using a spectrophotometric method we could readily measure the activity of DT-diaphorase in epidermis and various cultured pigment cells. The melanocytes isolated from dark skin showed generally higher DT-diaphorase activity than those from fair skin samples. Also, darkly pigmented congenital naevus cells exhibited higher activity of this enzyme. The most striking was the high DT-diaphorase activity in melanoma cell cultures. In these cells DT-diaphorase activity could be induced by incubation of the cells with 4-hydroxyanisole. A similar effect was seen when a catechol-O-methyltransferase (COMT) inhibitor (3-(3,4-dihydroxy-5-nitrobenzylidene)-2,4-pentanedione (OR-462) was utilised. The induction was inhibited by cyclohexidine.

Development of diagnostics in the search of an explanation for toxic airline syndrome 1

PubMed Central

Schopfer, Lawrence M.; Furlong, Clement E.; Lockridge, Oksana

2010-01-01

Toxic airline syndrome is assumed to be caused by exposure to tri-cresyl phosphate, an additive in engine lubricants and hydraulic fluids, which is activated to the toxic 2-(o-cresyl)-4H-1,3,2-benzodioxaphosphoran-2-one (CBDP). At present there is no laboratory evidence to support intoxication of airline crew by CBDP. Our goal was to develop methods for testing in vivo exposure by identifying and characterizing biomarkers. Mass spectrometry was used to study the reaction of CBDP with human albumin, free tyrosine, and human butyrylcholinesterase. Human albumin made a covalent bond with CBDP, adding a mass of 170 to tyrosine 411 to yield the ortho-cresyl phosphotyrosine derivative. Human butyrylcholinesterase made a covalent bond with CBDP on serine 198 to yield 5 adducts with added masses of 80, 108, 156, 170, and 186. The most abundant adduct had an added mass of 80 from phosphate (HPO3), a surprising result since no pesticide or nerve agent is known to yield phosphorylated serine with an added mass of 80. The next most abundant adduct had an added mass of 170 to form ortho-cresyl phosphoserine. It is concluded that toxic gases or oil mists in cabin air may form adducts on plasma butyrylcholinesterase and albumin, detectable by mass spectrometry. PMID:20447373

Theoretical study on the influence of different para-substituents on 13C NMR of the single carbonyl curcumin analogues

NASA Astrophysics Data System (ADS)

Jia, Fei-yun; Ran, Ming; Zhang, Bo

2015-12-01

The structure of eight kinds of different para-substituents curcumin analogues has been optimized at the level of B3LYP/6-31G( d, p), under which the stability has been verified by means of vibration analysis. Moreover, NMR spectra of curcumin analogues compounds have been studied at the level of B3LYP/6-311G( d, p) by GIAO method. The results show that the structure of eight compounds, a larger conjugated system, has good planarity. The effect of ortho-substituents on bond lengths and bond angles is greater than para and meta. Different substituents and different positions of substituents all have different influence on NMR of the single carbonyl curcumin analogues. In general, after the hydrogen atom on the benzene ring is substituted by other groups, the δ value of α-C changes significantly, the δ value of ortho-carbon atom may also have great change, but the δ value change of meta-carbon atoms is not too obvious. The effect of substituent electronegativity on α-C atoms presents obvious regularity, while the influence of conjugate effect on carbon atoms of benzene ring is more complex. Finally, the bigger substituted alkyl is, the more the δ value of α-C increases.

Synthesis, structure and stability of a chiral imine-based Schiff-based ligand derived from L-glutamic acid and its [Cu4] complex

NASA Astrophysics Data System (ADS)

Muche, Simon; Levacheva, Irina; Samsonova, Olga; Biernasiuk, Anna; Malm, Anna; Lonsdale, Richard; Popiołek, Łukasz; Bakowsky, Udo; Hołyńska, Małgorzata

2017-01-01

Studies of the stability of a ligand derived from L-glutamic acid and ortho-vanillin and its new [Cu4] complex are presented. The [Cu4] complex contains a heterocubane [CuII4O4] core and pendant carboxylic groups increasing its solubility in water, also under basic conditions. The stability of the complex in different solvents is confirmed with ESI-MS studies and such experiments as successful recrystallization. The complex is stable also under physiological conditions whereas the ligand is partly decomposed to L-glutamic acid and ortho-vanillin.

Ortho Group Activation of a Bromopyrrole Ester in Suzuki-Miyaura Cross-Coupling Reactions: Application to the Synthesis of New Microtubule Depolymerizing Agents with Potent Cytotoxic Activities

PubMed Central

Gupton, John T.; Yeudall, Scott; Telang, Nakul; Hoerrner, Megan; Huff, Ellis; Crawford, Evan; Lounsbury, Katie; Kimmel, Michael; Curry, William; Harrison, Andrew; Juekun, Wen; Shimozono, Alex; Ortolani, Joe; Lescalleet, Kristin; Patteson, Jon; Moore-Stoll, Veronica; Rohena, Cristina C.; Mooberry, Susan L.; Obaidullah, Ahmad J.; Kellogg, Glen E.; Sikorski, James A.

2017-01-01

New microtubule depolymerizing agents with potent cytotoxic activities have been prepared with a 5-cyano or 5-oximino group attached to a pyrrole core. The utilization of ortho activation of a bromopyrrole ester to facilitate successful Suzuki-Miyaura cross-coupling reactions was a key aspect of the synthetic methodology. This strategy allows for control of regiochemistry with the attachment of four completely different groups at the 2, 3, 4 and 5 positions of the pyrrole scaffold. Biological evaluations and molecular modeling studies are reported for these examples. PMID:28433513

Regioselective electrochemical reduction of 2,4-dichlorobiphenyl - Distinct standard reduction potentials for carbon-chlorine bonds using convolution potential sweep voltammetry

NASA Astrophysics Data System (ADS)

Muthukrishnan, A.; Sangaranarayanan, M. V.; Boyarskiy, V. P.; Boyarskaya, I. A.

2010-04-01

The reductive cleavage of carbon-chlorine bonds in 2,4-dichlorobiphenyl (PCB-7) is investigated using the convolution potential sweep voltammetry and quantum chemical calculations. The potential dependence of the logarithmic rate constant is non-linear which indicates the validity of Marcus-Hush theory of quadratic activation-driving force relationship. The ortho-chlorine of the 2,4-dichlorobiphenyl gets reduced first as inferred from the quantum chemical calculations and bulk electrolysis. The standard reduction potentials pertaining to the ortho-chlorine of 2,4-dichlorobiphenyl and that corresponding to para chlorine of the 4-chlorobiphenyl have been estimated.

Another side of the oxazaphospholidine oxide chiral ortho-directing group.

PubMed

Martins, Nelson; Mateus, Nuno; Vinci, Daniele; Saidi, Ourida; Brigas, Amadeu; Bacsa, John; Xiao, Jianliang

2012-05-28

A new ferrocenyl oxazaphospholidine oxide 3 was synthesized together with its P-epimer 2 in the reaction of ferrocene lithium with phosphoramidite chloride 1. 3 was successfully derivatized into planar chiral 1,2-ferrocenes, including phosphine ligands, via highly diastereoselective ortho-lithiation and subsequent functionalization; these compounds display opposite planar chirality to those obtained from 2. Some of these 1,2-ferrocenes were further lithiated, allowing for the introduction of a free phosphine group at the oxazaphospholidine ring. The X-ray structures of the compounds 2 and 3 as well as those of the new 1,2-ferrocenes 4 and 7 have been determined.

Kodak T-Mat G film in rotational panoramic radiography.

PubMed

Ponce, A Z; McDavid, W D; Lundeen, R C; Morris, C R

1986-06-01

Panoramic radiographs were taken of a tissue-equivalent phantom to evaluate T-Mat G and Ortho G films in combination with rare earth screens. The radiographs were compared to radiographs made with high-speed calcium tungstate screens and Kodak XRP film. The reduction in the amount of radiation necessary for the use of rare earth screens (50% to 70%) was accomplished by lowering the mA and adding filtration. All evaluated films were diagnostically acceptable. There was a marked preference of the T-Mat radiographs over the Ortho G radiographs and a slight preference over radiographs made with the standard calcium-tungstate screen-film system.

Herschel/SPIRE observations of water production rates and ortho-to-para ratios in comets★

NASA Astrophysics Data System (ADS)

Wilson, Thomas G.; Rawlings, Jonathan M. C.; Swinyard, Bruce M.

2017-04-01

This paper presents Herschel/SPIRE (Spectral and Photometric Imaging Receiver) spectroscopic observations of several fundamental rotational ortho- and para-water transitions seen in three Jupiter-family comets and one Oort-cloud comet. Radiative transfer models that include excitation by collisions with neutrals and electrons, and by solar infrared radiation, were used to produce synthetic emission line profiles originating in the cometary coma. Ortho-to-para ratios (OPRs) were determined and used to derived water production rates for all comets. Comparisons are made with the water production rates derived using an OPR of 3. The OPR of three of the comets in this study is much lower than the statistical equilibrium value of 3; however they agree with observations of comets 1P/Halley and C/2001 A2 (LINEAR), and the protoplanetary disc TW Hydrae. These results provide evidence suggesting that OPR variation is caused by post-sublimation gas-phase nuclear-spin conversion processes. The water production rates of all comets agree with previous work and, in general, decrease with increasing nucleocentric offset. This could be due to a temperature profile, additional water source or OPR variation in the comae, or model inaccuracies.

The structural analysis and modelling of ring substituent effect for the ortho-derivatives of 1-hydroxynaphthalene-2-carboxanilides and 2-hydroxynaphthalene-1-carboxanilides

NASA Astrophysics Data System (ADS)

Škorňa, Peter; Michalík, Martin; Lukeš, Vladimír; Klein, Erik

2017-09-01

The quantum chemical DFT study of 1-hydroxynaphthalene-2-carboxanilide (A-H) and 2-hydroxynaphthalene-1-carboxanilide (B-H) and their selected ortho-derivatives (A-R, B-R) is presented. The structural analysis showed that the energetically preferred conformation is stabilized via the intramolecular hydrogen bonds occurring between the Cdbnd O⋯H-O1 of A-H molecule and Cdbnd O⋯H-O2 groups of B-H molecule. The A-R derivatives are practically planar, while the B-R derivatives are slightly distorted due to the spatial repulsion of hydrogen atoms. The conformation analysis of molecules with deprotonated hydroxyl group supports the concept of existence of two conformer types with respect to the sbnd NHsbnd COsbnd bridge orientation. Stabilization of the naphtholate moiety by a hydrogen bond to the amide sbnd NHsbnd group may allow the compound to cross the membrane to the extracellular space. The ortho substitution effect on the selected calculated properties was analyzed and the theoretical data were correlated with the substituent constants. For the B-R derivatives, the antitubercular activity concentrations were correlated and predicted by the calculated quantities.

Comparison of estrogen-derived ortho-quinone and para-quinol concerning induction of oxidative stress.

PubMed

Rivera-Portalatin, Nilka M; Vera-Serrano, José L; Prokai-Tatrai, Katalin; Prokai, Laszlo

2007-01-01

Ortho-quinones formed from catechol estrogens are considered prooxidants due to the production of superoxide radical anions through redox cycling via semiquinones. Para-quinols have been identified as novel metabolites of and as the major products of hydroxyl-radical scavenging by estrogens. Cycling of these compounds has also been discovered, because they are converted back to the parent estrogen via reductive aromatization in vitro and in vivo. We hypothesized that, unlike ortho-quinones, para-quinols do not induce oxidative stress due to this cycling. Like the estrogen itself, the 17beta-estradiol-derived para-quinol (10beta,17beta-dihydroxyestra-1,4-diene-3-one) did not induce oxidative stress, as the rate of hydrogen peroxide production during the incubations of the compounds in various tissue homogenates was not significantly different from that of the control experiments performed without the addition of a test compound. We also confirmed that the estrogen metabolite estra-1,5(10)-dien-3,4,17-trione (estrone 3,4-quinone) was a profound prooxidant due to redox cycling, especially in uterine tissue. Therefore, we concluded that para-quinols do not induce oxidative stress.

Locked ortho- and para-core chromophores of green fluorescent protein; dramatic emission enhancement via structural constraint.

PubMed

Hsu, Yen-Hao; Chen, Yi-An; Tseng, Huan-Wei; Zhang, Zhiyun; Shen, Jiun-Yi; Chuang, Wei-Ti; Lin, Tzu-Chieh; Lee, Chun-Shu; Hung, Wen-Yi; Hong, Bor-Cherng; Liu, Shih-Hung; Chou, Pi-Tai

2014-08-20

We report the design strategy and synthesis of a structurally locked GFP core chromophore p-LHBDI, its ortho-derivative, o-LHBDI, and H2BDI possessing both para- and ortho-hydroxyl groups such that the inherent rotational motion of the titled compounds has been partially restricted. o-LHBDI possesses a doubly locked configuration, i.e., the seven-membered ring hydrogen bond and five-membered ring C(4-5-10-13-14) cyclization, from which the excited-state intramolecular proton transfer takes place, rendering a record high tautomer emission yield (0.18 in toluene) and the generation of amplified spontaneous emission. Compared with their unlocked counterparts, a substantial increase in the emission yield is also observed for p-LHBDI and H2BDI in anionic forms in water, and accordingly the structure versus luminescence relationship is fully discussed based on their chemistry and spectroscopy aspect. In solid, o-LHBDI exhibits an H-aggregate-like molecular packing, offers narrow-bandwidth emission, and has been successfully applied to fabricate a yellow organic light emitting diodes (λmax = 568 nm, ηext = 1.9%) with an emission full width at half-maximum as narrow as 70 nm.

CYP96T1 of Narcissus sp. aff. pseudonarcissus Catalyzes Formation of the Para-Para' C-C Phenol Couple in the Amaryllidaceae Alkaloids

PubMed Central

Kilgore, Matthew B.; Augustin, Megan M.; May, Gregory D.; Crow, John A.; Kutchan, Toni M.

2016-01-01

The Amaryllidaceae alkaloids are a family of amino acid derived alkaloids with many biological activities; examples include haemanthamine, haemanthidine, galanthamine, lycorine, and maritidine. Central to the biosynthesis of the majority of these alkaloids is a C-C phenol-coupling reaction that can have para-para', para-ortho', or ortho-para' regiospecificity. Through comparative transcriptomics of Narcissus sp. aff. pseudonarcissus, Galanthus sp., and Galanthus elwesii we have identified a para-para' C-C phenol coupling cytochrome P450, CYP96T1, capable of forming the products (10bR,4aS)-noroxomaritidine and (10bS,4aR)-noroxomaritidine from 4′-O-methylnorbelladine. CYP96T1 was also shown to catalyzed formation of the para-ortho' phenol coupled product, N-demethylnarwedine, as less than 1% of the total product. CYP96T1 co-expresses with the previously characterized norbelladine 4′-O-methyltransferase. The discovery of CYP96T1 is of special interest because it catalyzes the first major branch in Amaryllidaceae alkaloid biosynthesis. CYP96T1 is also the first phenol-coupling enzyme characterized from a monocot. PMID:26941773

Comparison of estrogen-derived ortho-quinone and para-quinol concerning induction of oxidative stress

PubMed Central

Rivera-Portalatin, Nilka M.; Vera-Serrano, José L.; Prokai-Tatrai, Katalin; Prokai, Laszlo

2009-01-01

Ortho-quinones formed from catechol estrogens are considered prooxidants due to the production of superoxide radical anions through redox cycling via semiquinones. Para-quinols have been identified as novel metabolites of and as the major products of hydroxyl-radical scavenging by estrogens. Cycling of these compounds has also been discovered, because they are converted back to the parent estrogen via reductive aromatization in vitro and in vivo. We hypothesized that, unlike ortho-quinones, para-quinols do not induce oxidative stress due to this cycling. Like the estrogen itself, the 17β-estradiol-derived para-quinol (10β,17β-dihydroxyestra-1,4-diene-3-one) did not induce oxidative stress, as the rate of hydrogen peroxide production during the incubations of the compounds in various tissue homogenates was not significantly different from that of the control experiments performed without the addition of a test compound. We also confirmed that the estrogen metabolite estra-1,5(10)-dien-3,4,17-trione (estrone 3,4-quinone) was a profound prooxidant due to redox cycling, especially in uterine tissue. Therefore, we concluded that para-quinols do not induce oxidative stress. PMID:17582759

Resonances in the reaction ortho- and para- D2 + H at temperatures below 10 K

NASA Astrophysics Data System (ADS)

Simbotin, I.; Côté, R.

2016-05-01

In a previous study we reported cross sections for the reaction H2 + D in the temperature regime 10-6 < T < 10 K, and found pronounced shape resonances, especially in the p and d partial waves. We found that the resonant structures were sensitive to the initial rovibrational state of H2; in particular, we showed that the effect of the nuclear-spin symmetry was very important, since ortho- and para- H2 gave significantly different results. We now investigate the reaction D2 + H for vibrationally excited ortho- and para- D2, and compare and contrast these results with those for H2 + D. We remark that this benchmark system is a prototypical example of reactions with a strong barrier, which have very small cross sections in the cold and ultracold regimes. However, shape resonances can enhance the reaction cross sections by orders of magnitude for temperatures around and below T = 1 K. Moreover, resonant features would provide stringent tests for quantum chemistry calculations of potential energy surfaces. Partial support from the US Army Research Office (Grant No. W911NF-13-1-0213).

Ortho stops marketing Lippes Loop; cites economic factors.

PubMed

1985-11-01

Ortho Pharmaceutical Corporation has stopped marketing the Lippes Loop IUD, the only inert IUD currently available in the US. The firm cited "economic considerations" as its reason. Linda Organ, company spokeswoman, told Contraceptive Technology Update (CTU) that the number of women using IUDs has declined in the past few years and, as a result, Ortho's Lippes Loop sales dropped. Most physicians, according to Organ, currently prescribe copper-bearing IUDs. Few devices have been studied as thoroughly before marketing as the Lippes Loop, according to its developer, Dr. Jack Lippes. Lippes told CTU that the Population Council analyzed 40,000 women from 1962 to 1968 and "found no trouble with the Loop." Lippes attributes Ortho's recent decision to 2 factors: the IUD has been only "marginally profitable" and the problems of A.H. Robins with the Dalkon Shield has most likely had an effect; and the US Food and Drug Administration (FDA) published a proposed rule in August 1985 that would require any company wanting to manufacture and market IUDs like the Lippes Loop to submit a premarketing approval application to that agency. In effect, the FDA's rule would only apply to the Lippes Loop. Under the proposed rule, any company wanting to market Lippes Loops, or any nondrug IUD, would have to submit an application to the FDA with a detailed discussion and supporting clinical studies addressing the following concerns: pelvic actinomycosis; tubal infertility; duration that the IUD should remain in situ; and safety of leaving the IUD in situ when contraception is no longer indicated. According to Lillian Yin, FDA device evaluation, the clinical effectiveness and most of the safety issues regarding inert IUDs have been thoroughly covered in published data. She told CTU that "most of the information needed is straightforward, but the part that's new involves the long term use infection rate." Yin indicated that the FDA received a letter from Ortho advising the agency of the company's decision to discontinue selling the loop. That decision, according to Organ, is not based on new study information about inert versus copper bearing IUDs. The company sent a letter to physicians on April 15 advising them of revisions in Lippes Loop patient and physician information materials. The added information is cited.

Development, evaluation and comparison of two independent sampling and analytical methods for ortho-phthalaldehyde vapors and condensation aerosols in air† ‡

PubMed Central

2015-01-01

Two independent sampling and analytical methods for ortho-phthalaldehyde (OPA) in air have been developed, evaluated and compared (1) a reagent-coated solid sorbent HPLC-UV method and (2) an impinger-fluorescence method. In the first method, air sampling is conducted at 1.0 L min−1 with a sampler containing 350 mg of silica gel coated with 1 mg of acidified 2,4-dinitrophenylhydrazine (DNPH). After sampling, excess DNPH in ethyl acetate is added to the sampler prior to storage for 68 hours. The OPA-DNPH derivative is eluted with 4.0 mL of dimethyl sulfoxide (DMSO) for measurement by HPLC with a UV detector set at 3S5 nm. The estimated detection limit is 0.016 µg per sample or 0.067 µg m−3 (0.012 ppb) for a 240 L air sample. Recoveries of vapor spikes at levels of 1.2 to 6.2 µg were 96 to 101%. Recoveries of spikes as mixtures of vapor and condensation aerosols were 97 to 100%. In the second method, air sampling is conducted at 1.0 L mm−1 with a midget impinger containing 10 mL of DMSO solution containing N-acetyl-l-cysteine and ethylenediamine. The fluorescence reading is taken 80 min after the completion of air sampling. Since the time of taking the fluorescence reading is critical, the reading is taken with a portable fluorometer. The estimated detection limit is 0.024 µg per sample or 0.1 µg m−3 (0.018 ppb) for a 240 L air sample. Recoveries of OPA vapor spikes at levels of 1.4 to 5.0 µg per sample were 97 to 105%. Recoveries of spikes as mixtures of vapors and condensation aerosols were 95 to 99%. The collection efficiency for a mixture of vapor and condensation aerosol was 99.4%. The two methods were compared side-by-side in a generation system constructed for producing controlled atmospheres of OPA vapor in air. Average air concentrations of OPA vapor found by both methods agreed within ±10%. PMID:26346658

Cadastral Resurvey using High Resolution Satellite Ortho Image - challenges: A case study in Odisha, India

NASA Astrophysics Data System (ADS)

Parida, P. K.; Sanabada, M. K.; Tripathi, S.

2014-11-01

Advancements in satellite sensor technology enabling capturing of geometrically accurate images of earth's surface coupled with DGPS/ETS and GIS technology holds the capability of large scale mapping of land resources at cadastral level. High Resolution Satellite Images depict field bunds distinctly. Thus plot parcels are to be delineated from cloud free ortho-images and obscured/difficult areas are to be surveyed using DGPS and ETS. The vector datasets thus derived through RS/DGPS/ETS survey are to be integrated in GIS environment to generate the base cadastral vector datasets for further settlement/title confirmation activities. The objective of this paper is to illustrate the efficacy of a hybrid methodology employed in Pitambarpur Sasana village under Digapahandi Tahasil of Ganjam district, as a pilot project, particularly in Odisha scenario where the land parcel size is very small. One of the significant observations of the study is matching of Cadastral map area i.e. 315.454 Acres, the image map area i.e. 314.887 Acres and RoR area i.e. 313.815 Acre. It was revealed that 79 % of plots derived by high-tech survey method show acceptable level of accuracy despite the fact that the mode of area measurement by ground and automated method has significant variability. The variations are more in case of Government lands, Temple/Trust lands, Common Property Resources and plots near to river/nalas etc. The study indicates that the adopted technology can be extended to other districts and cadastral resurvey and updating work can be done for larger areas of the country using this methodology.

Automatic Feature Detection, Description and Matching from Mobile Laser Scanning Data and Aerial Imagery

NASA Astrophysics Data System (ADS)

Hussnain, Zille; Oude Elberink, Sander; Vosselman, George

2016-06-01

In mobile laser scanning systems, the platform's position is measured by GNSS and IMU, which is often not reliable in urban areas. Consequently, derived Mobile Laser Scanning Point Cloud (MLSPC) lacks expected positioning reliability and accuracy. Many of the current solutions are either semi-automatic or unable to achieve pixel level accuracy. We propose an automatic feature extraction method which involves utilizing corresponding aerial images as a reference data set. The proposed method comprise three steps; image feature detection, description and matching between corresponding patches of nadir aerial and MLSPC ortho images. In the data pre-processing step the MLSPC is patch-wise cropped and converted to ortho images. Furthermore, each aerial image patch covering the area of the corresponding MLSPC patch is also cropped from the aerial image. For feature detection, we implemented an adaptive variant of Harris-operator to automatically detect corner feature points on the vertices of road markings. In feature description phase, we used the LATCH binary descriptor, which is robust to data from different sensors. For descriptor matching, we developed an outlier filtering technique, which exploits the arrangements of relative Euclidean-distances and angles between corresponding sets of feature points. We found that the positioning accuracy of the computed correspondence has achieved the pixel level accuracy, where the image resolution is 12cm. Furthermore, the developed approach is reliable when enough road markings are available in the data sets. We conclude that, in urban areas, the developed approach can reliably extract features necessary to improve the MLSPC accuracy to pixel level.

Optimized and validated flow-injection spectrophotometric analysis of topiramate, piracetam and levetiracetam in pharmaceutical formulations.

PubMed

Hadad, Ghada M; Abdel-Salam, Randa A; Emara, Samy

2011-12-01

Application of a sensitive and rapid flow injection analysis (FIA) method for determination of topiramate, piracetam, and levetiracetam in pharmaceutical formulations has been investigated. The method is based on the reaction with ortho-phtalaldehyde and 2-mercaptoethanol in a basic buffer and measurement of absorbance at 295 nm under flow conditions. Variables affecting the determination such as sample injection volume, pH, ionic strength, reagent concentrations, flow rate of reagent and other FIA parameters were optimized to produce the most sensitive and reproducible results using a quarter-fraction factorial design, for five factors at two levels. Also, the method has been optimized and fully validated in terms of linearity and range, limit of detection and quantitation, precision, selectivity and accuracy. The method was successfully applied to the analysis of pharmaceutical preparations.

Ph-activated nano-amorphous calcium phosphate-based cement to reduce dental enamel demineralization.

PubMed

Melo, Mary A S; Weir, Michael D; Passos, Vanara F; Powers, Michael; Xu, Hockin H K

2017-12-01

Enamel demineralization is destructive, esthetically compromised, and costly complications for orthodontic patients. Nano-sized amorphous calcium phosphate (NACP) has been explored to address this challenge. The 20% NACP-loaded ortho-cement notably exhibited favorable behavior on reducing demineralization of enamel around brackets in a caries model designed to simulate the carious attack. The 20% NACP-loaded ortho-cement markedly promotes higher calcium and phosphate release at a low pH, and the mineral loss was almost two fold lower and carious lesion depth decreased the by 1/3. This novel approach is promising co-adjuvant route for prevention of dental caries dissemination in millions of patients under orthodontic treatment.

Base-Controlled Completely Selective Linear or Branched Rhodium(I)-Catalyzed C-H ortho-Alkylation of Azines without Preactivation.

PubMed

Tran, Gaël; Hesp, Kevin D; Mascitti, Vincent; Ellman, Jonathan A

2017-05-15

A [Rh I ]/bisphosphine/base catalytic system for the ortho-selective C-H alkylation of azines by acrylates and acrylamides is reported. This catalytic system features an unprecedented complete linear or branched selectivity that is solely dependent on the catalytic base that is used. Complete branched selectivity is even achieved for ethyl methacrylate, which enables the introduction of a quaternary carbon center. Excellent functional group compatibility is demonstrated for both linear and branched alkylations. The operational simplicity and broad scope of this transformation allow for rapid access to functionalized azines of direct pharmaceutical and agrochemical relevance. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

GO-Cu7S4 catalyzed ortho-aminomethylation of phenol derivatives with N,N-dimethylbenzylamines: site-selective oxidative CDC.

PubMed

Gupta, Sonu; Chandna, Nisha; Dubey, Pooja; Singh, Ajai K; Jain, Nidhi

2018-06-21

Copper chalcogenide nanoparticles (Cu7S4) supported on graphene oxide (GO) have been synthesized for the first time from Cu2S, and used as highly efficient heterogeneous catalysts for oxidative ortho-selective C-H aminomethylation of phenols with N,N-dimethylbenzylamines. The NPs (30-80 nm) have been characterized by HRTEM, SEM-EDX, PXRD, FTIR, Raman, ICP-AES and XPS analyses. The NP catalyzed sp2-sp3 cross dehydrogenative coupling (CDC) features a broad substrate scope, excellent functional group tolerance, high yields, use of an inexpensive and reusable copper catalyst, mild conditions, and no need for pre-functionalization of substrates.

Spectroscopic probing of ortho-nitrophenol localization in phospholipid bilayers.

PubMed

Sánchez, Julieta M; Turina, Anahí del V; Perillo, María A

2007-11-12

In the present study we estimated the localization of ortho-nitrophenol (ONP) within model membranes through its efficiency to quench and to modify the anisotropy of DPH and TMA-DPH fluorescence. These fluorescent probes are known to sense the hydrocarbon core and the polar head group region of membranes, respectively. TMA-DPH fluorescence in MLVs was more efficiently quenched than DPH (K(q,TMA-DPH)=2.36 and K(q,DPH)=1.07 mM ns(-1)). Moreover, these results demonstrated the interfacial localization of ONP and may contribute to understand membrane-mediated mechanisms of ONP-induced toxicity and the behavior of ONP as a product of several enzymatic reactions occurring in the presence of lipid-water interfaces.

Surface Temperature Dependence of Hydrogen Ortho-Para Conversion on Amorphous Solid Water.

PubMed

Ueta, Hirokazu; Watanabe, Naoki; Hama, Tetsuya; Kouchi, Akira

2016-06-24

The surface temperature dependence of the ortho-to-para conversion of H_{2} on amorphous solid water is first reported. A combination of photostimulated desorption and resonance-enhanced multiphoton ionization techniques allowed us to sensitively probe the conversion on the surface of amorphous solid water at temperatures of 9.2-16 K. Within a narrow temperature window of 8 K, the conversion time steeply varied from ∼4.1×10^{3} to ∼6.4×10^{2}  s. The observed temperature dependence is discussed in the context of previously suggested models and the energy dissipation process. The two-phonon process most likely dominates the conversion rate at low temperatures.

Human Tissues Investigation Using PALS Technique

NASA Astrophysics Data System (ADS)

Jasińska, B.; Zgardzińska, B.; Chołubek, G.; Gorgol, M.; Wiktor, K.; Wysogląd, K.; Białas, P.; Curceanu, C.; Czerwiński, E.; Dulski, K.; Gajos, A.; Głowacz, B.; Hiesmayr, B.; Jodłowska-Jędrych, B.; Kamińska, D.; Korcyl, G.; Kowalski, P.; Kozik, T.; Krawczyk, N.; Krzemień, W.; Kubicz, E.; Mohammed, M.; Pawlik-Niedźwiecka, M.; Niedźwiecki, S.; Pałka, M.; Raczyński, L.; Rudy, Z.; Sharma, N. G.; Sharma, S.; Shopa, R.; Silarski, M.; Skurzok, M.; Wieczorek, A.; Wiktor, H.; Wiślicki, W.; Zieliński, M.; Moskal, P.

Samples of uterine leiomyomatis and normal tissues taken from patients after surgery were investigated using the Positron Annihilation Lifetime Spectroscopy (PALS). Significant differences in all PALS parameters between normal and diseased tissues were observed. For all studied patients, it was found that the values of the free annihilation and ortho-positronium lifetime are larger for the tumorous tissues than for the healthy ones. For most of the patients, the intensity of the free annihilation and ortho-positronium annihilation was smaller for the tumorous than for the healthy tissues. For the first time, in this kind of studies, the $3\\gamma$ fraction of positron annihilation was determined to describe changes in the tissue porosity during morphologic alteration.

Nucleophilic addition of amines to ruthenium carbenes: ortho-(alkynyloxy)benzylamine cyclizations towards 1,3-benzoxazines.

PubMed

González-Rodríguez, Carlos; Suárez, José Ramón; Varela, Jesús A; Saá, Carlos

2015-02-23

A new ruthenium-catalyzed cyclization of ortho-(alkynyloxy)benzylamines to dihydro-1,3-benzoxazines is reported. The cyclization is thought to take place via the vinyl ruthenium carbene intermediates which are easily formed from [Cp*RuCl(cod)] and N2 CHSiMe3 . The mild reaction conditions and the efficiency of the procedure allow the easy preparation of a broad range of new 2-vinyl-2-substituted 1,3-benzoxazine derivatives. Rearrangement of an internal C(sp) in the starting material into a tetrasubstituted C(sp(3) ) atom in the final 1,3-benzoxazine is highly remarkable. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design of ortho-Substituted Donor-Acceptor Molecules as Highly Efficient Green Thermally Activated Delayed Fluorescent Emitters

NASA Astrophysics Data System (ADS)

Cha, Jae-Ryung; Gong, Myoung-Seon; Lee, Tak Jae; Ha, Tae Hoon; Lee, Chil Won

2018-04-01

The ortho-substituted donor-acceptor molecules 2-(4,6-diphenyl-1, 3, 5-triazin-2-yl)- N,Ndiphenylaniline (DPA- o-Trz) and 2-(4,6-diphenyl-1, 3, 5-triazine-2-yl)- N,N-di- p-tolylaniline (MPA- o-Trz) were designed, synthesized, and found to exhibit green fluorescence characteristics. Notably, the singlet-triplet energy gap was less than 0.1 eV, indicating that reverse intersystem crossing gave rise to thermally activated delayed fluorescence (TADF). The organic light-emitting device performance of MPA- o-Trz showed a high external quantum efficiency of 16.3% and good color stability from 0.1 cd/m2 to 5000 cd/m2.

Theoretical Study of the Mechanism Behind the para-Selective Nitration of Toluene in Zeolite H-Beta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andersen, Amity; Govind, Niranjan; Subramanian, Lalitha

Periodic density functional theory calculations were performed to investigate the origin of the favorable para-selective nitration of toluene exhibited by zeolite H-beta with acetyl nitrate nitration agent. Energy calculations were performed for each of the 32 crystallographically unique Bronsted acid sites of a beta polymorph B zeolite unit cell with multiple Bronsted acid sites of comparable stability. However, one particular aluminum T-site with three favorable Bronsted site oxygens embedded in a straight 12-T channel wall provides multiple favorable proton transfer sites. Transition state searches around this aluminum site were performed to determine the barrier to reaction for both para andmore » ortho nitration of toluene. A three-step process was assumed for the nitration of toluene with two organic intermediates: the pi- and sigma-complexes. The rate limiting step is the proton transfer from the sigma-complex to a zeolite Bronsted site. The barrier for this step in ortho nitration is shown to be nearly 2.5 times that in para nitration. This discrepancy appears to be due to steric constraints imposed by the curvature of the large 12-T pore channels of beta and the toluene methyl group in the ortho approach that are not present in the para approach.« less

Contamination by polychlorinated biphenyls (PCBs) in striped dolphins (Stenella coeruleoalba) from the Southeastern Mediterranean Sea.

PubMed

Storelli, Maria Maddalena; Barone, Grazia; Giacominelli-Stuffler, Roberto; Marcotrigiano, Giuseppe Onofrio

2012-09-01

Concentrations of polychlorinated biphenyls (PCBs) including dioxin-like PCBs (non-ortho, PCB 77, PCB 126, and PCB 169 and mono-ortho, PCB 105, PCB 118, and PCB 156) were measured in different organs and tissues (melon, blubber, liver, kidney, lung, heart, and muscle tissue) of striped dolphins (Stenella coeruleoalba) from the Eastern Mediterranean Sea (Adriatic Sea). The mean highest levels were in blubber and melon, followed by liver, kidney, lung, heart, and muscle tissue. PCB profiles were similar in all tissues and organs being dominated by the higher chlorinated homologues (hexa-CBs, 55.8-62.1%; penta-CBs, 15.4-20.0%; and hepta-CB PCB 180, 12.7-16.5%). Major PCBs in all tissues were congeners 138 and 153 collectively accounting for 50.6-58.3% of the total PCB concentrations, followed by PCB 101, 105, 118, and 180 constituting from 27.0% to 31.0%. PCB levels were higher in adult males than in adult females. The estimated 2,3,7,8-TCDD toxic equivalents of non- and mono-ortho PCBs were much higher than the threshold level above which adverse effects have been observed in other marine mammals species, suggesting that striped dolphins in this region are at risk for toxic effects.

A new ab initio potential energy surface for the collisional excitation of HCN by para- and ortho-H2

NASA Astrophysics Data System (ADS)

Denis-Alpizar, Otoniel; Kalugina, Yulia; Stoecklin, Thierry; Vera, Mario Hernández; Lique, François

2013-12-01

We present a new four-dimensional potential energy surface for the collisional excitation of HCN by H2. Ab initio calculations of the HCN-H2 van der Waals complex, considering both molecules as rigid rotors, were carried out at the explicitly correlated coupled cluster with single, double, and perturbative triple excitations [CCSD(T)-F12a] level of theory using an augmented correlation-consistent triple zeta (aVTZ) basis set. The equilibrium structure is linear HCN-H2 with the nitrogen pointing towards H2 at an intermolecular separation of 7.20 a0. The corresponding well depth is -195.20 cm-1. A secondary minimum of -183.59 cm-1 was found for a T-shape configuration with the H of HCN pointing to the center of mass of H2. We also determine the rovibrational energy levels of the HCN-para-H2 and HCN-ortho-H2 complexes. The calculated dissociation energies for the para and ortho complexes are 37.79 cm-1 and 60.26 cm-1, respectively. The calculated ro-vibrational transitions in the HCN-H2 complex are found to agree by more than 0.5% with the available experimental data, confirming the accuracy of the potential energy surface.

A second ortho-rhom-bic polymorph of (Z)-3-(9-anthr-yl)-1-(2-thien-yl)prop-2-en-1-one.

PubMed

Chantrapromma, Suchada; Suwunwong, Thitipone; Boonnak, Nawong; Fun, Hoong-Kun

2010-01-09

The title heteroaryl chalcone, C(21)H(14)OS, is a second ortho-rhom-bic polymorph which crystallizes in the space group P2(1)2(1)2(1). The structure was previously reported [Fun et al. (2009 ▶). Acta Cryst. E65, o2168-o2169] in the space group Pna2(1). The bond distances and angles are similar in both structures. In contrast, the overall crystal packing is different from that in the first ortho-rhom-bic Pna2(1) polymorph in which mol-ecules were stacked into columns along the b axis and the thio-phene units of two adjacent columns were stacked in a head to tail fashion. In the present polymorph, mol-ecules are found to dimerize through a weak S⋯S inter-action [3.6513 (7) Å] and these dimers are arranged into sheets parallel to the bc plane. There are no classical hydrogen bonds in the packing which features short C⋯O [3.2832 (2)-3.6251 (9) Å], C⋯S [3.4879 (17)-3.6251 (19) Å] and S⋯O [2.9948 (16) Å] contacts, together with C-H⋯π inter-actions. Similar contacts were found in the other polymorph.

Acid-degradable lactobionic acid-modified soy protein nanogels crosslinked by ortho ester linkage for efficient antitumor in vivo.

PubMed

Cheng, Xu; Qin, Jiejie; Wang, Xin; Zha, Qian; Yao, Weijing; Fu, Shengxiang; Tang, Rupei

2018-05-03

It remains a crucial challenge to achieve efficient cellular uptake and intracellular drug release in tumor cells for the nanoscale drug delivery systems. Herein, acid-degradable nanogels were prepared by cross-linking methacrylated soy protein with an acid-labile ortho ester cross-linker (NG1), and then modified with lactobionic acid (LA) to give tumor-targeted nanogels (NG2). Both NG1 and NG2 displayed excellent stability in neutral environment, while showed pH-triggered degradation behaviors under mildly acidic conditions resulting from the breakage of ortho ester bonds. Doxorubicin (DOX) was successfully loaded into nanogels, which exhibited an accelerated release at low pH. In vitro cell studies demonstrated that LA-modified nanogels could effectively improve cellular internalization, show higher cytotoxicity and apoptosis toward asialoglycoprotein receptor (ASGPR) over-expressed HepG2 cells. In vivo antitumor experimentproved that LA modification could significantly enhance the tumor-targeting ability of nanogels and increase DOX concentration in tumor site, leading to better therapeutic efficacy. Histological analysis further demonstrated that soy protein-based nanogels did not cause any damage to normal organs. Overall, these pH-sensitive and tumor-targeting soy protein-based nanogels can be potential drug carriers for efficient tumor treatment. Copyright © 2018. Published by Elsevier B.V.

Conversion of chlorobiphenyls into phenylhexadienoates and benzoates by the enzymes of the upper pathway for polychlorobiphenyl degradation encoded by the bph locus of Pseudomonas sp. strain LB400.

PubMed Central

Seeger, M; Timmis, K N; Hofer, B

1995-01-01

Metabolism of 21 chlorobiphenyls by the enzymes of the upper biphenyl catabolic pathway encoded by the bph locus of Pseudomonas sp. strain LB400 was investigated by using recombinant strains harboring gene cassettes containing bphABC or bphABCD. The enzymes of the upper pathway were generally able to metabolize mono- and dichlorinated biphenyls but only partially transform most trichlorinated congeners investigated: 14 of 15 mono- and dichlorinated and 2 of 6 trichlorinated congeners were converted into benzoates. All mono- and at least 8 of 12 dichlorinated congeners were attacked by the bphA-encoded biphenyl dioxygenase virtually exclusively at ortho and meta carbons. This enzyme exhibited a high degree of selectivity for the aromatic ring to be attacked, with the order of ring preference being non- > ortho- > meta- > para-substituted for mono- and dichlorinated congeners. The influence of the chlorine substitution pattern of the metabolized ring on benzoate formation resembled its influence on the reactivity of initial dioxygenation, suggesting that the rate of benzoate formation may frequently be determined by the rate of initial attack. The absorption spectra of phenylhexadienoates formed correlated with the presence or absence of a chlorine substituent at an ortho position. PMID:7618878

Rotational relaxation of CS by collision with ortho- and para-H{sub 2} molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denis-Alpizar, Otoniel; Departamento de Física, Universidad de Matanzas, Matanzas 40100; Stoecklin, Thierry, E-mail: t.stoecklin@ism.u-bordeaux1.fr

Quantum mechanical investigation of the rotationally inelastic collisions of CS with ortho- and para-H{sub 2} molecules is reported. The new global four-dimensional potential energy surface presented in our recent work is used. Close coupling scattering calculations are performed in the rigid rotor approximation for ortho- and para-H{sub 2} colliding with CS in the j = 0–15 rotational levels and for collision energies ranging from 10{sup −2} to 10{sup 3} cm{sup −1}. The cross sections and rate coefficients for selected rotational transitions of CS are compared with the ones previously reported for the collision of CS with He. The largest discrepanciesmore » are observed at low collision energy, below 1 cm{sup −1}. Above 10 cm{sup −1}, the approximation using the square root of the relative mass of the colliders to calculate the cross sections between a molecule and H{sub 2} from the data available with {sup 4}He is found to be a good qualitative approximation. The rate coefficients calculated with the electron gas model for the He-CS system show more discrepancy with our accurate results. However, scaling up these rates by a factor of 2 gives a qualitative agreement.« less

Spin conversion of positronium in NiO/Al2O3 catalysts observed by coincidence Doppler broadening technique

NASA Astrophysics Data System (ADS)

Zhang, H. J.; Chen, Z. Q.; Wang, S. J.; Kawasuso, A.; Morishita, N.

2010-07-01

High-purity NiO/Al2O3 catalysts were prepared by mixing NiO and γ-Al2O3 nanopowders. X-ray diffraction patterns were measured to characterize the grain size and crystalline phase of the nanopowders. Positron-annihilation spectroscopy was used to study the microstructure and surface properties of the pores inside the NiO/Al2O3 catalysts. The positron lifetime spectrum comprises two short and two long lifetime components. The two long lifetimes τ3 and τ4 correspond to ortho-positronium (o-Ps) annihilated in microvoids and large pores, respectively. With increasing NiO content in the NiO/Al2O3 catalysts, both τ4 and its intensity I4 show continuous decrease. Meanwhile, the para-positronium (p-Ps) intensity, obtained from coincidence Doppler broadening spectra, increases gradually with NiO content. The different variation in o-Ps and p-Ps intensity suggests the ortho-para conversion of positronium in NiO/Al2O3 catalysts. X-ray photoelectron spectroscopy shows that Ni mainly exists in the form of NiO. The electron-spin-resonance measurements reveal that the ortho-para conversion of Ps is induced by the unpaired electrons of the paramagnetic centers of NiO.

H{sub 2}—AgCl: A spectroscopic study of a dihydrogen complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grubbs, G. S.; Obenchain, Daniel A.; Pickett, Herbert M.

2014-09-21

H{sub 2}—AgCl has been observed on a Fourier transform microwave spectrometer equipped with laser ablation source and determined to be a dihydrogen complex. Transitions up to J = 3–2 have been measured and analyzed for four isotopologues of the complex containing ortho and para H{sub 2}. The ortho and para spin states have been included in one fit, a deviation from the typical H{sub 2} complex. Rotational constants B and C, centrifugal distortion constants Δ{sub J} and Δ{sub JK}, nuclear electric quadrupole coupling constants χ{sub aa}, χ{sub bb}, and χ{sub cc} for {sup 35}Cl and {sup 37}Cl have been fitmore » for both spin states while nuclear spin-nuclear spin constants D{sub aa}, D{sub bb}, and D{sub cc}, and nuclear spin-rotation constant C{sub aa} have been reported for the ortho spin state. Quantum chemical calculations predict a strong bonding interaction and the strength of the complex has been related to reported χ{sub aa} and Δ{sub J} values amongst a host of comparable species, including the AgCl monomer itself. Bond lengths have been determined for Ag—Cl, Ag—H{sub 2} center-of-mass, and H—H and are reported.« less

Mass spectrometry of analytical derivatives. 2. "Ortho" and "Para" effects in electron ionization mass spectra of derivatives of hydroxy, mercapto and amino benzoic acids.

PubMed

Todua, Nino G; Mikaia, Anzor I

2016-01-01

Derivatives requiring either anhydrous or aqueous reaction conditions were prepared for robust and reliable gas chromatography/mass spectrometry (GC/MS) characterization of hydroxyl, mercapto, and amino benzoic acids Methylation and trialkylsilytation are employed for blocking the acidic function. Alkyl, trimethylsilyl, acetyl, perfluoroacyl and alkoxycarbonyl derivatization groups are introduced to hydroxyl, mercapto and amino functions. The electron ionization induced fragmentation characteristics of corresponding derivatives are explained by comparing the MS 1 spectra of unlabeled compounds to their 2 H and 13 C labeled analogs, and analysis of collision-induced dissociation data from MS 2 spectra. Competing fragmentation alternatives are identified and specific decomposition processes are detailed that characterize (a) ortho isomers due to interaction or vicinal functional substituents and (b) para isomers prone to forming para quinoid type structures. Skeletal and hydrogen rearrangements typical for methyl benzoates and the blocking groups are considered when discussing diagnostically important ions. Characteristic ions produced as a result of rearrangements in ortho isomers are classified, and skeletal rearrangements required to produce para quinoid type ions specific for para isomers are noted. Key ions for structure elucidation and differentiation of isomers for derivatives of substituted benzoic acids by GC/MS are suggested.

Structure-Kinetics Correlations in Isostructural Crystals of α-(ortho-Tolyl)-acetophenones: Pinning Down Electronic Effects Using Laser-Flash Photolysis in the Solid State.

PubMed

Ayitou, Anoklase J-L; Flynn, Kristen; Jockusch, Steffen; Khan, Saeed I; Garcia-Garibay, Miguel A

2016-03-02

Aqueous suspensions of nanocrystals in the 200-500 nm size range of isostructural α-(ortho-tolyl)-acetophenone (1a) and α-(ortho-tolyl)-para-methylacetophenone (1b) displayed good absorption characteristics for flash photolysis experiments in a flow system, with transient spectra and decay kinetics with a quality that is similar to that recorded in solution. In contrast to solution measurements, reactions in the solid state were characterized by a rate limiting hydrogen transfer reaction from the triplet excited state and a very short-lived biradical intermediate, which does not accumulate. Notably, the rate for δ-hydrogen atom transfer of 1a (2.7 × 10(7) s(-1)) in the crystalline phase is 18-fold larger than that of 1b (1.5 × 10(6) s(-1)). With nearly identical molecular and crystal structures, this decrease in the rate of δ-hydrogen abstraction can be assigned unambiguously to an electronic effect by the para-methyl group in 1b, which increases the contribution of the (3)π,π* configuration relative to the reactive (3)n,π* configuration in the lowest triplet excited state. These results highlight the potential of relating single crystal X-ray structural data with absolute kinetics from laser flash photolysis.

Intramolecular Hydrogen Bonding in Benzoxazines: When Structural Design Becomes Functional.

PubMed

Froimowicz, Pablo; Zhang, Kan; Ishida, Hatsuo

2016-02-18

The future evolution of benzoxazines and polybenzoxazines as advanced molecular, structural, functional, engineering, and newly commercial materials depends to a great extent on a deeper and more fundamental understanding at the molecular level. In this contribution, the field of benzoxazines is briefly introduced along with a more detailed review of ortho-amide-functional benzoxazines, which are the main subjects of this article. Provided in this article are the detailed and solid scientific evidences of intramolecular five-membered-ring hydrogen bonding, which is supposed to be responsible for the unique and characteristic features exhibited by this ever-growing family of ortho-functionalized benzoxazines. One-dimensional (1D) (1)H NMR spectroscopy was used to study various concentrations of benzoxazines in various solvents with different hydrogen-bonding capability and at various temperatures to investigate in detail the nature of hydrogen bonding in both ortho-amide-functionalized benzoxazine and its para counterpart. These materials were further investigated by two-dimensional (2D) (1)H-(1)H nuclear Overhauser effect spectroscopy (NOESY) to verify and support the conclusions derived during the 1D (1)H NMR experiments. Only highly purified single-crystal benzoxazine samples have been used for this study to avoid additional interactions caused by any impurities. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Geosynthesis of organic compounds: I. Alkylphenols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ioppolo-Armanios, M.; Alexander, R.; Kagi, R.I.

1995-07-01

Methylation, isopropylation, and sec-butylation are proposed as geosynthetic processes to account for the alkylphenol compositions of crude oils with phenol distributions dominated by ortho and para substituted compounds. Phenol distributions in eleven crude oils and four kerogen pyrolysates were analysed using GC-MS (gas chromatography-mass spectrometry). Ten of the crude oils show high relative abundances of ortho and para substituted phenol isomers and some were also enriched in C{sub 3}-C{sub 5} alkylphenols compared to the kerogen pyrolysates. Because the distributions of products obtained from the laboratory alkylation of cresols closely resemble those of phenols in these crude oils, we propose thatmore » similar alkylation processes occur in source rocks. Alkylation ratios reflecting the degree of methylation, isopropylation, and sec-butylation, which were based on the relative abundance of the dominant alkylation products compared to their likely precursor ortho-cresol, indicate that high levels of methylation occurred in crude oils over a wide range of maturities, whereas high levels of isopropylation and sec-butylation were observed only in mature samples. Dissolution of the phenols in crude oils by water contact was discounted as an explanation for the observed phenol distributions based on the relative distribution coefficients of phenols between a hydrocarbon phase and water.« less

Efficacy of Fe(o,o-EDDHA) and Fe(o,p-EDDHA) isomers in supplying Fe to strategy I plants differs in nutrient solution and calcareous soil.

PubMed

Rojas, Carmen L; Romera, Francisco J; Alcántara, Esteban; Pérez-Vicente, Rafael; Sariego, Cristina; Garcaí-Alonso, J Ignacio; Boned, Javier; Marti, Gabriel

2008-11-26

The FeEDDHA [iron(3+) ethylenediamine di(o-hydroxyphenylacetic) acid] is one of the most efficient iron chelates employed in the correction of iron clorosis in calcareous soils. FeEDDHA presents different positional isomers: the ortho-ortho (o,o), the ortho-para (o,p), and the para-para (p,p). Of these isomers, the p,p cannot chelate Fe in soil solution in a wide range of pH values, while both o,o and o,p can. The objective of this work was to compare the efficiency of both isomers (o,o and o,p) to provide Fe to two Strategy I plants (tomato and peach) in nutrient solution (pH approximately 6.0), as well as in calcareous soil (pH approximately 8.4; CALCIXEREPT). For this, chelates of both o,o-EDDHA and o,p-EDDHA with 57Fe (a nonradioactive isotope of Fe) were used, where the 57Fe acts as a tracer. The results obtained showed that the o,o isomer is capable of providing sufficient Fe to plants in both nutrient solution and calcareous soil. However, the o,p isomer is capable of providing sufficient Fe to plants in nutrient solution but not in calcareous soil.

Rovibrational transitions of H2 by collision with H+ at high temperature

NASA Astrophysics Data System (ADS)

González-Lezana, T.; Honvault, P.

2017-05-01

The H+ + H2 reaction is studied by means of both exact and statistical quantum methods. Integral cross-sections for processes initiated with rotationally excited H2(v, j = 1) to produce molecular hydrogen in its rotational ground state are reported up to a value of the collision energy of 3 eV. Rate constants for state-to-state transitions between different H2 rovibrational states are calculated up to 3000 K. Special emphasis is made on ortho/para conversion processes in which the parity j of the H2(j) states changes.

First time-dependent study of H{sub 2} and H{sub 3}{sup +} ortho-para chemistry in the diffuse interstellar medium: Observations meet theoretical predictions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albertsson, T.; Semenov, D.; Henning, Th.

The chemistry in the diffuse interstellar medium (ISM) initiates the gradual increase of molecular complexity during the life cycle of matter. A key molecule that enables build-up of new molecular bonds and new molecules via proton donation is H{sub 3}{sup +}. Its evolution is tightly related to molecular hydrogen and thought to be well understood. However, recent observations of ortho and para lines of H{sub 2} and H{sub 3}{sup +} in the diffuse ISM showed a puzzling discrepancy in nuclear spin excitation temperatures and populations between these two key species. H{sub 3}{sup +}, unlike H{sub 2}, seems to be outmore » of thermal equilibrium, contrary to the predictions of modern astrochemical models. We conduct the first time-dependent modeling of the para-fractions of H{sub 2} and H{sub 3}{sup +} in the diffuse ISM and compare our results to a set of line-of-sight observations, including new measurements presented in this study. We isolate a set of key reactions for H{sub 3}{sup +} and find that the destruction of the lowest rotational states of H{sub 3}{sup +} by dissociative recombination largely controls its ortho/para ratio. A plausible agreement with observations cannot be achieved unless a ratio larger than 1:5 for the destruction of (1, 1)- and (1, 0)-states of H{sub 3}{sup +} is assumed. Additionally, an increased cosmic-ray ionization rate to 10{sup –15} s{sup –1} further improves the fit whereas variations of other individual physical parameters, such as density and chemical age, have only a minor effect on the predicted ortho/para ratios. Thus, our study calls for new laboratory measurements of the dissociative recombination rate and branching ratio of the key ion H{sub 3}{sup +} under interstellar conditions.« less

High Spectral Resolution SOFIA/EXES Observations of C2H2 toward Orion IRc2

NASA Astrophysics Data System (ADS)

Rangwala, Naseem; Colgan, Sean W. J.; Le Gal, Romane; Acharyya, Kinsuk; Huang, Xinchuan; Lee, Timothy J.; Herbst, Eric; deWitt, Curtis; Richter, Matt; Boogert, Adwin; McKelvey, Mark

2018-03-01

We present high spectral resolution observations from 12.96 to 13.33 microns toward Orion IRc2 using the mid-infrared spectrograph, Echelon-Cross-Echelle Spectrograph (EXES), at Stratospheric Observatory for Infrared Astronomy (SOFIA). These observations probe the physical and chemical conditions of the Orion hot core, which is sampled by a bright, compact, mid-infrared background continuum source in the region, IRc2. All 10 of the rovibrational C2H2 transitions expected in our spectral coverage are detected with high signal-to-noise ratios (S/Ns), yielding continuous coverage of the R-branch lines from J = 9–8 to J = 18–17, including both ortho and para species. Eight of these rovibrational transitions are newly reported detections. The isotopologue, 13CCH2, is clearly detected with a high S/N. This enabled a direct measurement of the 12C/13C isotopic ratio for the Orion hot core of 14 ± 1 and an estimated maximum value of 21. We also detected several HCN rovibrational lines. The ortho and para C2H2 ladders are clearly separate, and tracing two different temperatures, 226 K and 164 K, respectively, with a non-equilibrium ortho to para ratio (OPR) of 1.7 ± 0.1. Additionally, the ortho and para V LSR values differ by about 1.8 ± 0.2 km s‑1, while the mean line widths differ by 0.7 ± 0.2 km s‑1, suggesting that these species are not uniformly mixed along the line of sight to IRc2. We propose that the abnormally low C2H2 OPR could be a remnant from an earlier, colder phase, before the density enhancement (now the hot core) was impacted by shocks generated from an explosive event 500 years ago.

Quantum mechanical study of the proton exchange in the ortho-para H2 conversion reaction at low temperature.

PubMed

Honvault, P; Jorfi, M; González-Lezana, T; Faure, A; Pagani, L

2011-11-14

Ortho-para H(2) conversion reactions mediated by the exchange of a H(+) proton have been investigated at very low energy for the first time by means of a time independent quantum mechanical (TIQM) approach. State-to-state probabilities and cross sections for H(+) + H(2) (v = 0, j = 0,1) processes have been calculated for a collision energy, E(c), ranging between 10(-6) eV and 0.1 eV. Differential cross sections (DCSs) for H(+) + H(2) (v = 0, j = 1) → H(+) + H(2) (v' = 0, j' = 0) for very low energies only start to develop a proper global minimum around the sideways scattering direction (θ≈ 90°) at E(c) = 10(-3) eV. Rate coefficients, a crucial information required for astrophysical models, are provided between 10 K and 100 K. The relaxation ortho-para process j = 1 → j' = 0 is found to be more efficient than the j = 0 → j' = 1 conversion at low temperatures, in line with the extremely small ratio between the ortho and para species of molecular hydrogen predicted at the temperature of interstellar cold molecular clouds. The results obtained by means of a statistical quantum mechanical (SQM) model, which has previously proved to provide an adequate description of the dynamics of the title reactions at a higher collision energy regime, have been compared with the TIQM results. A reasonable good agreement has been found with the only exception of the DCSs for the H(+) + H(2) (v = 0, j = 1) → H(+) + H(2) (v' = 0, j' = 0) process at very low energy. SQM cross sections are also slightly below the quantum results. Estimates for the rate coefficients, in good accord with the TIQM values, are a clear improvement with respect to pioneering statistical studies on the reaction.

First Time-dependent Study of H2 and H_3^+ Ortho-Para Chemistry in the Diffuse Interstellar Medium: Observations Meet Theoretical Predictions

NASA Astrophysics Data System (ADS)

Albertsson, T.; Indriolo, N.; Kreckel, H.; Semenov, D.; Crabtree, K. N.; Henning, Th.

2014-05-01

The chemistry in the diffuse interstellar medium (ISM) initiates the gradual increase of molecular complexity during the life cycle of matter. A key molecule that enables build-up of new molecular bonds and new molecules via proton donation is H_3^+. Its evolution is tightly related to molecular hydrogen and thought to be well understood. However, recent observations of ortho and para lines of H2 and H_3^+ in the diffuse ISM showed a puzzling discrepancy in nuclear spin excitation temperatures and populations between these two key species. H_3^+, unlike H2, seems to be out of thermal equilibrium, contrary to the predictions of modern astrochemical models. We conduct the first time-dependent modeling of the para-fractions of H2 and H_3^+ in the diffuse ISM and compare our results to a set of line-of-sight observations, including new measurements presented in this study. We isolate a set of key reactions for H_3^+ and find that the destruction of the lowest rotational states of H_3^+ by dissociative recombination largely controls its ortho/para ratio. A plausible agreement with observations cannot be achieved unless a ratio larger than 1:5 for the destruction of (1, 1)- and (1, 0)-states of H_3^+ is assumed. Additionally, an increased cosmic-ray ionization rate to 10-15 s-1 further improves the fit whereas variations of other individual physical parameters, such as density and chemical age, have only a minor effect on the predicted ortho/para ratios. Thus, our study calls for new laboratory measurements of the dissociative recombination rate and branching ratio of the key ion H_{3}^{+} under interstellar conditions. Partly based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile, as part of program 088.C-0351.

Full-dimensional quantum dynamics of CO in collision with H{sub 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Benhui; Stancil, P. C.; Balakrishnan, N.

Inelastic scattering computations are presented for collisions of vibrationally and rotationally excited CO with H{sub 2} in full dimension. The computations utilize a newly developed six-dimensional potential energy surface (PES) and the previously reported four-dimensional V12 PES [P. Jankowski et al., J. Chem. Phys. 138, 084307 (2013)] and incorporate full angular-momentum coupling. At low collision energies, pure rotational excitation cross sections of CO by para-, ortho-, and normal-H{sub 2} are calculated and convolved to compare with recent measurements. Good agreement with the measured data is shown except for j{sub 1} = 0 → 1 excitation of CO for very low-energymore » para-H{sub 2} collisions. Rovibrational quenching results are presented for initially excited CO(v{sub 1}j{sub 1}) levels with v{sub 1} = 1, j{sub 1} = 1–5 and v{sub 1} = 2, j{sub 1} = 0 for collisions with para-H{sub 2} (v{sub 2} = 0, j{sub 2} = 0) and ortho-H{sub 2} (v{sub 2} = 0, j{sub 2} = 1) over the kinetic energy range 0.1–1000 cm{sup −1}. The total quenching cross sections are found to have similar magnitudes, but increase (decrease) with j{sub 1} for collision energies above ∼300 cm{sup −1} (below ∼10 cm{sup −1}). Only minor differences are found between para- and ortho-H{sub 2} colliders for rovibrational and pure rotational transitions, except at very low collision energies. Likewise, pure rotational deexcitation of CO yields similar cross sections for the v{sub 1} = 0 and v{sub 1} = 1 vibrational levels, while rovibrational quenching from v{sub 1} = 2, j{sub 1} = 0 is a factor of ∼5 larger than that from v{sub 1} = 1, j{sub 1} = 0. Details on the PES, computed at the CCSD(T)/aug-cc-pV5Z level, and fitted with an invariant polynomial method, are also presented.« less

A comparison of shear bond strength of orthodontic brackets bonded with four different orthodontic adhesives

PubMed Central

Sharma, Sudhir; Tandon, Pradeep; Nagar, Amit; Singh, Gyan P; Singh, Alka; Chugh, Vinay K

2014-01-01

Objectives: The objective of this study is to compare the shear bond strength (SBS) of stainless steel (SS) orthodontic brackets bonded with four different orthodontic adhesives. Materials and Methods: Eighty newly extracted premolars were bonded to 0.022 SS brackets (Ormco, Scafati, Italy) and equally divided into four groups based on adhesive used: (1) Rely-a-Bond (self-cure adhesive, Reliance Orthodontic Product, Inc., Illinois, USA), (2) Transbond XT (light-cure adhesive, 3M Unitek, CA, USA), (3) Transbond Plus (sixth generation self-etch primer, 3M Unitek, CA, USA) with Transbond XT (4) Xeno V (seventh generation self-etch primer, Dentsply, Konstanz, Germany) with Xeno Ortho (light-cure adhesive, Dentsply, Konstanz, Germany) adhesive. Brackets were debonded with a universal testing machine (Model No. 3382 Instron Corp., Canton, Mass, USA). The adhesive remnant index (ARI) was recordedIn addition, the conditioned enamel surfaces were observed under a scanning electron microscope (SEM). Results: Transbond XT (15.49 MPa) attained the highest bond strength. Self-etching adhesives (Xeno V, 13.51 MPa; Transbond Plus, 11.57 MPa) showed clinically acceptable SBS values and almost clean enamel surface after debonding. The analysis of variance (F = 11.85, P < 0.0001) and Chi-square (χ2 = 18.16, P < 0.05) tests revealed significant differences among groups. The ARI score of 3 (i.e., All adhesives left on the tooth) to be the most prevalent in Transbond XT (40%), followed by Rely-a-Bond (30%), Transbond Plus with Transbond XT (15%), and Xeno V with Xeno Ortho (10%). Under SEM, enamel surfaces after debonding of the brackets appeared porous when an acid-etching process was performed on the surfaces of Rely-a-Bond and Transbond XT, whereas with self-etching primers enamel presented smooth and almost clean surfaces (Transbond Plus and Xeno V group). Conclusion: All adhesives yielded SBS values higher than the recommended bond strength (5.9-7–8 MPa), Seventh generation self-etching primer Xeno V with Xeno Ortho showed clinically acceptable SBS and the least amount of residual adhesive left on the enamel surface after debonding. PMID:24987660

The Domestication of ortho-Quinone Methides

PubMed Central

2015-01-01

Conspectus An ortho-quinone methide (o-QM) is a highly reactive chemical motif harnessed by nature for a variety of purposes. Given its extraordinary reactivity and biological importance, it is surprising how few applications within organic synthesis exist. We speculate that their widespread use has been slowed by the complications that surround the preparation of their precursors, the harsh generation methods, and the omission of this stratagem from computer databases due to its ephemeral nature. About a decade ago, we discovered a mild anionic triggering procedure to generate transitory o-QMs at low temperature from readily available salicylaldehydes, particularly OBoc derivatives. This novel reaction cascade included both the o-QM formation and the subsequent consumption reaction. The overall transformation was initiated by the addition of the organometallic reagent, usually a Grignard reagent, which resulted in the formation of a benzyloxy alkoxide. Boc migration from the neighboring phenol produced a magnesium phenoxide that we supposed underwent β-elimination of the transferred Boc residue to form an o-QM for immediate further reactions. Moreover, the cascade proved controllable through careful manipulation of metallic and temperature levers so that it could be paused, stopped, or restarted at various intermediates and stages. This new level of domestication enabled us to deploy o-QMs for the first time in a range of applications including diastereocontrolled reactions. This sequence ultimately could be performed in either multipot or single pot processes. The subsequent reaction of the fleeting o-QM intermediates included the 1,4-conjugate additions that led to unbranched or branched ortho-alkyl substituted phenols and Diels–Alder reactions that provided 4-unsubstituted or 4-substituted benzopyrans and chroman ketals. The latter cycloadducts were obtained for the first time with outstanding diastereocontrol. In addition, the steric effects of the newly created stereocenters in subsequent reactions of chroman ketals and acetals were studied and proved predictable. Through the use of a chiral auxiliary, Diels–Alder products were deployed in numerous enantioselective reactions including several complex natural products syntheses. In this Account, we summarize our efforts, which we hope have contributed to the synthetic renaissance for this venerable species. PMID:25469551

Analysis of the effects of exposure to polychlorinated biphenyls and chlorinated pesticides on serum lipid levels in residents of Anniston, Alabama

PubMed Central

2013-01-01

Background Anniston, Alabama, is the site of a former Monsanto plant where polychlorinated biphenyls (PCBs) were manufactured from 1929 until 1971. Residents of Anniston are known to have elevated levels of PCBs. The objective of the study was to test the hypothesis that levels of the various lipid components (total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides) are differentially associated with concentrations of total PCBs and total pesticides, and further that different congeners, congener groups and different pesticides do not have identical associations in serum samples obtained from Anniston residents in a cross-sectional study. Methods Fasting serum samples were obtained from 575 residents of Anniston who were not on any lipid-lowering medication and were analyzed for 35 PCB congeners, nine chlorinated pesticides, total cholesterol, LDL and HDL cholesterol and triglyceride concentrations. Associations between toxicant concentrations and lipid levels were determined using multiple linear regression analysis. Results We observed that elevated serum concentrations of lipids were associated with elevated serum concentrations of ΣPCBs and summed pesticides in analyses adjusted for age, race, gender, BMI, alcohol consumption, smoking and exercising status. The strongest associations were seen for PCB congeners with three, four, or at least eight substituted chlorines. Mono-ortho substituted congeners 74 and 156, di-ortho congeners 172 and 194, and tri- and tetra-ortho congeners 199, 196–203, 206 and 209 each were significantly associated with total lipids, total cholesterol and triglycerides. Serum concentrations of HCB and chlordane also had strong associations with lipid components. Conclusions Increased concentrations of PCBs and organochlorine pesticides are associated with elevations in total serum lipids, total cholesterol and triglycerides, but the patterns are different for different groups of PCBs and different pesticides. These observations show selective effects of different organochlorines on serum concentrations of different groups of lipids. This elevation in concentrations of serum lipids may be the basis for the increased incidence of cardiovascular disease found in persons with elevated exposures to PCBs and chlorinated pesticides. PMID:24325314

Positron annihilation in SiO 2-Si studied by a pulsed slow positron beam

NASA Astrophysics Data System (ADS)

Suzuki, R.; Ohdaira, T.; Uedono, A.; Kobayashi, Y.

2002-06-01

Positron and positronium (Ps) behavior in SiO 2-Si have been studied by means of positron annihilation lifetime spectroscopy (PALS) and age-momentum correlation (AMOC) spectroscopy with a pulsed slow positron beam. The PALS study of SiO 2-Si samples, which were prepared by a dry-oxygen thermal process, revealed that the positrons implanted in the Si substrate and diffused back to the interface do not contribute to the ortho-Ps long-lived component, and the lifetime spectrum of the interface has at least two components. From the AMOC study, the momentum distribution of the ortho-Ps pick-off annihilation in SiO 2, which shows broader momentum distribution than that of crystalline Si, was found to be almost the same as that of free positron annihilation in SiO 2. A varied interface model was proposed to interpret the results of the metal-oxide-semiconductor (MOS) experiments. The narrow momentum distribution found in the n-type MOS with a negative gate bias voltage could be attributed to Ps formation and rapid spin exchange in the SiO 2-Si interface. We have developed a two-dimensional positron lifetime technique, which measures annihilation time and pulse height of the scintillation gamma-ray detector for each event. Using this technique, the positronium behavior in a porous SiO 2 film, grown by a sputtering method, has been studied.

Extraction of Airport Features from High Resolution Satellite Imagery for Design and Risk Assessment

NASA Technical Reports Server (NTRS)

Robinson, Chris; Qiu, You-Liang; Jensen, John R.; Schill, Steven R.; Floyd, Mike

2001-01-01

The LPA Group, consisting of 17 offices located throughout the eastern and central United States is an architectural, engineering and planning firm specializing in the development of Airports, Roads and Bridges. The primary focus of this ARC project is concerned with assisting their aviation specialists who work in the areas of Airport Planning, Airfield Design, Landside Design, Terminal Building Planning and design, and various other construction services. The LPA Group wanted to test the utility of high-resolution commercial satellite imagery for the purpose of extracting airport elevation features in the glide path areas surrounding the Columbia Metropolitan Airport. By incorporating remote sensing techniques into their airport planning process, LPA wanted to investigate whether or not it is possible to save time and money while achieving the equivalent accuracy as traditional planning methods. The Affiliate Research Center (ARC) at the University of South Carolina investigated the use of remotely sensed imagery for the extraction of feature elevations in the glide path zone. A stereo pair of IKONOS panchromatic satellite images, which has a spatial resolution of 1 x 1 m, was used to determine elevations of aviation obstructions such as buildings, trees, towers and fence-lines. A validation dataset was provided by the LPA Group to assess the accuracy of the measurements derived from the IKONOS imagery. The initial goal of this project was to test the utility of IKONOS imagery in feature extraction using ERDAS Stereo Analyst. This goal was never achieved due to problems with ERDAS software support of the IKONOS sensor model and the unavailability of imperative sensor model information from Space Imaging. The obstacles encountered in this project pertaining to ERDAS Stereo Analyst and IKONOS imagery will be reviewed in more detail later in this report. As a result of the technical difficulties with Stereo Analyst, ERDAS OrthoBASE was used to derive aviation obstruction measurements for this project. After collecting ancillary data such as GPS locations, South Carolina Geodetic Survey and Aero Dynamics ground survey points to set up the OrthoBASE Block File, measurements were taken of the various glide path obstructions and compared to the validation dataset. This process yielded the following conclusions: The IKONOS stereo model in conjunction with Imagine OrthoBASE can provide The LPA Group with a fast and cost efficient method for assessing aviation obstructions. Also, by creating our own stereo model we achieved any accuracy better currently available commercial products.

A versatile method for the determination of photochemical quantum yields via online UV-Vis spectroscopy.

PubMed

Stadler, Eduard; Eibel, Anna; Fast, David; Freißmuth, Hilde; Holly, Christian; Wiech, Mathias; Moszner, Norbert; Gescheidt, Georg

2018-05-16

We have developed a simple method for determining the quantum yields of photo-induced reactions. Our setup features a fibre coupled UV-Vis spectrometer, LED irradiation sources, and a calibrated spectrophotometer for precise measurements of the LED photon flux. The initial slope in time-resolved absorbance profiles provides the quantum yield. We show the feasibility of our methodology for the kinetic analysis of photochemical reactions and quantum yield determination. The typical chemical actinometers, ferrioxalate and ortho-nitrobenzaldehyde, as well as riboflavin, a spiro-compound, phosphorus- and germanium-based photoinitiators for radical polymerizations and the frequently utilized photo-switch azobenzene serve as paradigms. The excellent agreement of our results with published data demonstrates the high potential of the proposed method as a convenient alternative to the time-consuming chemical actinometry.

GoPros™ as an underwater photogrammetry tool for citizen science

PubMed Central

David, Peter A.; Dupont, Sally F.; Mathewson, Ciaran P.; O’Neill, Samuel J.; Powell, Nicholas N.; Williamson, Jane E.

2016-01-01

Citizen science can increase the scope of research in the marine environment; however, it suffers from necessitating specialized training and simplified methodologies that reduce research output. This paper presents a simplified, novel survey methodology for citizen scientists, which combines GoPro imagery and structure from motion to construct an ortho-corrected 3D model of habitats for analysis. Results using a coral reef habitat were compared to surveys conducted with traditional snorkelling methods for benthic cover, holothurian counts, and coral health. Results were comparable between the two methods, and structure from motion allows the results to be analysed off-site for any chosen visual analysis. The GoPro method outlined in this study is thus an effective tool for citizen science in the marine environment, especially for comparing changes in coral cover or volume over time. PMID:27168973

GoPros™ as an underwater photogrammetry tool for citizen science.

PubMed

Raoult, Vincent; David, Peter A; Dupont, Sally F; Mathewson, Ciaran P; O'Neill, Samuel J; Powell, Nicholas N; Williamson, Jane E

2016-01-01

Citizen science can increase the scope of research in the marine environment; however, it suffers from necessitating specialized training and simplified methodologies that reduce research output. This paper presents a simplified, novel survey methodology for citizen scientists, which combines GoPro imagery and structure from motion to construct an ortho-corrected 3D model of habitats for analysis. Results using a coral reef habitat were compared to surveys conducted with traditional snorkelling methods for benthic cover, holothurian counts, and coral health. Results were comparable between the two methods, and structure from motion allows the results to be analysed off-site for any chosen visual analysis. The GoPro method outlined in this study is thus an effective tool for citizen science in the marine environment, especially for comparing changes in coral cover or volume over time.

Post surgical pain management with poly(ortho esters).

PubMed

Barr, John; Woodburn, Kathryn W; Ng, Steven Y; Shen, Hui-Rong; Heller, Jorge

2002-10-16

Poly(ortho esters), POE, are synthetic bioerodible polymers that can be prepared as solid materials, or as viscous, injectable polymers. These materials have evolved through a number of families, and the latest member of this family, POE IV, is particularly well suited to drug delivery since latent acid is integrated into the polymer backbone, thereby, modulating surface erosion. POE IV predominantly undergoes surface erosion and is able to moderate drug release over periods from days to many months. One indication in which the POE IV polymer is currently being investigated is in sustained post-surgical pain management. The local anesthetic agent, mepivacaine, has been incorporated into a viscous, injectable POE IV and its potential to provide longer-acting anesthesia has been explored in non-clinical models.

New rate coefficients of CS in collision with para- and ortho-H2 and astrophysical implications

NASA Astrophysics Data System (ADS)

Denis-Alpizar, Otoniel; Stoecklin, Thierry; Guilloteau, Stéphane; Dutrey, Anne

2018-05-01

Astronomers use the CS molecule as a gas mass tracer in dense regions of the interstellar medium, either to measure the gas density through multi-line observations or the level of turbulence. This necessarily requires the knowledge of the rates coefficients with the most common colliders in the interstellar medium, He and H2. In the present work, the close coupling collisional rates are computed for the first thirty rotational states of CS in collision with para- and ortho-H2 using a recent rigid rotor potential energy surface. Some radiative transfer calculations, using typical astrophysical conditions, are also performed to test this new set of data and to compare with the existing ones.

Ortho-, meta-, and para-benzyne. A comparative CCSD (T) investigation

NASA Astrophysics Data System (ADS)

Kraka, Elfi; Cremer, Dieter

1993-12-01

Geometries and energies of ortho-benzyne ( 1), mata-benzyne ( 2), and para-benzyne ( 3) have been calculated at the CCSD (T), GVB, GVB-LSDC, and MBPT (2) levels of theory employing the 6-31G(d, p) basis. Calculations suggest relative energies of O, 13.7, and 25.3 kcal/mol, respectively, and Δ H0f(298) values of 110.8, 123.9, and 135.7 kcal/mol for 1, 2, and 3. With the Δ H0f(298) value of 3, the reaction enthalpy Δ RH(298) and the activation enthalpy Δ H#(298) for the Bergman cyclization of (Z)-hexa-1,5-diy -ene to 3 are calculated to be 9.1 and 28.5 kcal/mol.

Carbon Nanotube Formic Acid Sensors Using a Nickel Bis( ortho-diiminosemiquinonate) Selector.

PubMed

Lin, Sibo; Swager, Timothy M

2018-03-23

Formic acid is corrosive, and a sensitive and selective sensor could be useful in industrial, medical, and environmental settings. We present a chemiresistor for detection of formic acid composed of single-walled carbon nanotubes (CNTs) and nickel bis( ortho-diiminosemiquinonate) (1), a planar metal complex that can act as a ditopic hydrogen-bonding selector. Formic acid is detected in concentrations as low as 83 ppb. The resistance of the material decreases on exposure to formic acid, but slightly increases on exposure to acetic acid. We propose that 1 assists in partial protonation of the CNT by formic acid, but the response toward acetic acid is dominated by inter-CNT swelling. This technology establishes CNT-based chemiresistive discrimination between formic and acetic acid vapors.

Measurements of the H2(13)CO ortho/para ratio in cold dark molecular clouds

NASA Technical Reports Server (NTRS)

Minh, Y. C.; Dickens, J. E.; Irvine, W. M.; McGonagle, D.

1995-01-01

H2(13)CO has been detected for the first time toward cold dark molecular clouds using the NRAO 12 m telescope. The H2(13)CO ortho/para abundance ratio R for B335, which we report as R approximately 1.7, suggests equilibrium at the local kinetic temperature and appears to be distinctly different from that for both TMC-1 and L134N, where R is close to or higher than the statistical value 3. Since only B335 among the observed positions includes an imbedded IR source, this difference may result from heating of the grain surfaces, providing the energy necessary for desorption of formaldehyde formed on the grains.

Ortho-phthalic acid esters in lipophilic extract from the cell culture of Aconitum baicalense Turcz ex Rapaics 1907.

PubMed

Semenov, A A; Enikeev, A G; Snetkova, L V; Permyakov, A V; Sokolova, N A; Dudareva, L V

2016-11-01

Optically active bis-2R(-)ethylhexyl o-phthalate was obtained with 0.18% yield from dry cultured cells of Aconitum baicalense Turcz ex Rapaics 1907 by extraction with petroleum ether followed by silica gel column chromatography. Its structure was confirmed by the analysis of 13 C and 1 H NMR spectra. Seasonal fluctuations of quantitative phthalate content in A. baicalense cells were identified. The tests were performed under conditions excluding the presence of phthalates in reagents, materials, and laboratory dishes. The same substance was shown to be produced by cultivated cells of other plants. Biosynthesis of esters of ortho-phthalic acid by cultivated plant cells was discovered for the first time.

The Abundances of Methane and Ortho/Para Hydrogen in Uranus and Neptune: Implications of New Laboratory 4-0 H(sub 2) Quadrapole Line Parameters

NASA Technical Reports Server (NTRS)

Baines, K.; Mickelson, M.; Larson, L.; Ferguson, D.

1994-01-01

The tropospheric methane molar fraction (f(sub ch4,t)) and the ortho/para hydrogen ratio are derived for Uranus and Neptune based on new determinations of spectroscopic parameters for key hydrogen features as reported by Ferguson et al. (1993, J. Mol. Spec 160, 315-325). For each planet, the relatively weak laboratory linestrengths (approximately 30% and 15% less than the theoretical 4-0 S(0) and S(1) linestrengths, respectively) results, when compared to analyses adopting theoretical values, in a 30% decrease in the tropospheric methane ratio and a comparable increase in the pressure level of the optically-thick cloudtop marking the bottom of the visible atmosphere (P(sub cld)).

Positron annihilation in a metal-oxide semiconductor studied by using a pulsed monoenergetic positron beam

NASA Astrophysics Data System (ADS)

Uedono, A.; Wei, L.; Tanigawa, S.; Suzuki, R.; Ohgaki, H.; Mikado, T.; Ohji, Y.

1993-12-01

The positron annihilation in a metal-oxide semiconductor was studied by using a pulsed monoenergetic positron beam. Lifetime spectra of positrons were measured as a function of incident positron energy for a polycrystalline Si(100 nm)/SiO2(400 nm)/Si specimen. Applying a gate voltage between the polycrystalline Si film and the Si substrate, positrons implanted into the specimen were accumulated at the SiO2/Si interface. From the measurements, it was found that the annihilation probability of ortho-positronium (ortho-Ps) drastically decreased at the SiO2/Si interface. The observed inhibition of the Ps formation was attributed to an interaction between positrons and defects at the SiO2/Si interface.

Information yield: a comparison of Kodak T-Mat G, Ortho L and RP X-Omat films.

PubMed

Miles, D A; Van Dis, M L; Peterson, M G

1989-02-01

The information yield from two rare-earth screen-film combinations, Lanex Regular/T-Mat G (TMG) and Lanex regular/Ortho L (OL) has been compared with that from a conventional calcium-tungstate combination, X-Omatic regular/RP X-Omat (XRP), by means of perceptibility curves generated from an aluminum test object. The TMG and OL systems were faster than the XRP and the OL had the widest latitude. The maximum number of details perceived was similar for all three systems. The results support the suggestion that the TMG and OL systems permit more information to be perceived than XRP and that the newer imaging systems do not lose information despite their increased speed.

Ortho-para H₂ conversion by proton exchange at low temperature: an accurate quantum mechanical study.

PubMed

Honvault, P; Jorfi, M; González-Lezana, T; Faure, A; Pagani, L

2011-07-08

We report extensive, accurate fully quantum, time-independent calculations of cross sections at low collision energies, and rate coefficients at low temperatures for the H⁺ + H₂(v = 0, j) → H⁺ + H₂(v = 0, j') reaction. Different transitions are considered, especially the ortho-para conversion (j = 1 → j' = 0) which is of key importance in astrophysics. This conversion process appears to be very efficient and dominant at low temperature, with a rate coefficient of 4.15 × 10⁻¹⁰ cm³ molecule⁻¹ s⁻¹ at 10 K. The quantum mechanical results are also compared with statistical quantum predictions and the reaction is found to be statistical in the low temperature regime (T < 100 K).

Fish contamination by polychlorobiphenyls: the mass spectrometric ortho effect in a new and easy gas chromatography-mass spectrometry method for the analysis of the seven indicators. The case of Bluefin Tuna.

PubMed

Masci, Maurizio; Orban, Elena; Nevigato, Teresina

2015-01-02

A simple instrumental procedure was developed to carry out the not simple analysis of PCBs in fish samples. PCBs with the same degree of chlorination (the isomers) are expected to be totally indistinguishable among them by all existing detectors and by all existing mass spectrometers, and there is no apparent solution in those frequent cases where two isomers chromatographically coelute. Generally such coelutions are solved by means of multidimensional GC, but it is a complex technique impractical for most laboratories. The present research focuses on the seven important "indicator PCBs" by using the mass spectrometer in an innovative way. The "mass spectrometric ortho effect" was usefully exploited in addressing coelutions between isomers. Other new important observations on mass spectra were decisive in solving the apparent problem arising from coelutions between higher chlorinated PCBs with the lower chlorinated ones when low-resolution MS is used. With the proposed procedure, the seven indicators are analyzed in a simple way and with a degree of accuracy never observed with the conventional gas chromatography. The method was applied to some Bluefin Tuna fish samples of big size suspected to have not negligible levels of PCBs due to the high position of this species in the food chain. The supposition was partly confirmed. On the basis of the results here obtained, the recently introduced EU Regulation on six of the seven indicators shows one critical point: in the present paper, an amendment to the Regulation is proposed. A number of important validation measures are reported. Copyright © 2014 Elsevier B.V. All rights reserved.

Measurements for 8 common analytes in native sera identify inadequate standardization among 6 routine laboratory assays.

PubMed

Stepman, Hedwig C M; Tiikkainen, Ulla; Stöckl, Dietmar; Vesper, Hubert W; Edwards, Selvin H; Laitinen, Harri; Pelanti, Jonna; Thienpont, Linda M

2014-06-01

External quality assessment (EQA) with commutable samples is essential for assessing the quality of assays performed by laboratories, particularly when the emphasis is on their standardization status and interchangeability of results. We used a panel of 20 fresh-frozen single-donation serum samples to assess assays for the measurement of creatinine, glucose, phosphate, uric acid, total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides. The commercial random access platforms included: Abbott Architect, Beckman Coulter AU, Ortho Vitros, Roche Cobas, Siemens Advia, and Thermo Scientific Konelab. The assessment was done at the peer group level and by comparison against the all-method trimmed mean or reference method values, where available. The considered quality indicators were intraassay imprecision, combined imprecision (including sample-matrix interference), bias, and total error. Fail/pass decisions were based on limits reflecting state-of-the-art performance, but also limits related to biological variation. Most assays showed excellent peer performance attributes, except for HDL- and LDL cholesterol. Cases in which individual assays had biases exceeding the used limits were the Siemens Advia creatinine (-4.2%), Ortho Vitros phosphate (8.9%), Beckman Coulter AU triglycerides (5.4%), and Thermo Scientific Konelab uric acid (6.4%), which lead to considerable interassay discrepancies. Additionally, large laboratory effects were observed that caused interlaboratory differences of >30%. The design of the EQA study was well suited for monitoring different quality attributes of assays performed in daily laboratory practice. There is a need for improvement, even for simple clinical chemistry analytes. In particular, the interchangeability of results remains jeopardized both by assay standardization issues and individual laboratory effects. © 2014 The American Association for Clinical Chemistry.

The mother of the pill.

PubMed

Djerassi, C

1995-01-01

The first synthesis of an active ingredient of the pill was performed on October 15, 1951, at Syntex in Mexico City. These preliminary results, obtained in late 1951, encouraged the submission of a synthetic progestin, norethindrone (19-nor-17alpha-ethynyltestosterone), to a number of outside investigators for more extensive biological scrutiny. Norethynodrel, together with many other steroids synthesized in the Searle laboratories, as well as Syntex's norethindrone, were examined by Pincus and collaborators for ovulation inhibition in animals and humans. Contrary to predictions, orally effective steroid ovulation inhibitors became the most widely used method of reversible birth control in most parts of the world some 40 years after their first synthesis. Toward the end of the 1960s, at least 13 international pharmaceutical companies (9 of them US) had active research and development programs dedicated to new advances in the field of contraception. Every drug to which a woman or man is exposed to for long periods of time (e.g., vaccines, systemic contraceptives, cholesterol-lowering agents, antihypertensives) in the end has to pass through large-scale postmarketing experiments. The most damaging was the requirement for 6-year toxicology in beagle dogs, which resulted in enormous development costs. Another setback was a 1986 judgment in Georgia against Ortho Pharmaceutical Company for the amount of $5,151,030 for alleged birth defects caused by the use of its spermicide Ortho-Gynol in spite of overwhelming epidemiological evidence against such a cause-effect relationship. Mifepristone (RU-486) is clearly the most significant new development in birth control as an important alternative to conventional abortion. A priority list of six new contraceptive methods for future development includes a spermicide with antiviral properties, a once-a-month menses inducer, a reliable ovulation predictor, easily reversible male sterilization, a male contraceptive pill, and an antifertility vaccine.

Structure from motion, a low cost, very high resolution method for surveying glaciers using GoPros and opportunistic helicopter flights

NASA Astrophysics Data System (ADS)

Girod, L.; Nuth, C.; Schellenberger, T.

2014-12-01

The capability of structure from motion techniques to survey glaciers with a very high spatial and temporal resolution is a promising tool for better understanding the dynamic changes of glaciers. Modern software and computing power allow us to produce accurate data sets from low cost surveys, thus improving the observational capabilities on a wider range of glaciers and glacial processes. In particular, highly accurate glacier volume change monitoring and 3D movement computations will be possible Taking advantage of the helicopter flight needed to survey the ice stakes on Kronenbreen, NW Svalbard, we acquired high resolution photogrammetric data over the well-studied Midre Lovénbreen in September 2013. GoPro Hero 2 cameras were attached to the landing gear of the helicopter, acquiring two images per second. A C/A code based GPS was used for registering the stereoscopic model. Camera clock calibration is obtained through fitting together the shapes of the flight given by both the GPS logger and the relative orientation of the images. A DEM and an ortho-image are generated at 30cm resolution from 300 images collected. The comparison with a 2005 LiDAR DEM (5 meters resolution) shows an absolute error in the direct registration of about 6±3m in 3D which could be easily reduced to 1,5±1m by using fine point cloud alignment algorithms on stable ground. Due to the different nature of the acquisition method, it was not possible to use tie point based co-registration. A combination of the DEM and ortho-image is shown with the point cloud in figure below. A second photogrammetric data set will be acquired in September 2014 to survey the annual volume change and movement. These measurements will then be compared to the annual resolution glaciological stake mass balance and velocity measurements to assess the precision of the method to monitor at an annual resolution.

Morphology, topography, and optics of the orthokeratology cornea

NASA Astrophysics Data System (ADS)

Faria-Ribeiro, Miguel; Belsue, Rafael Navarro; López-Gil, Norberto; González-Méijome, José Manuel

2016-07-01

The goal of this work was to objectively characterize the external morphology, topography, and optics of the cornea after orthokeratology (ortho-k). A number of 24 patients between the ages of 17 and 30 years (median=24 years) were fitted with Corneal Refractive Therapy® contact lenses to correct myopia between -2.00 and -5.00 diopters (D) (median=-3.41 D). A classification algorithm was applied to conduct an automatic segmentation based on the mean local curvature. As a result, three zones (optical zone, transition zone, and peripheral zone) were delimited. Topographical analysis was provided through global and zonal fit to a general ellipsoid. Ray trace on partially customized eye models provided wave aberrations and retinal image quality. Monozone topographic description of the ortho-k cornea loses accuracy when compared with zonal description. Primary (C40) and secondary (C60) spherical aberration (SA) coefficients for a 5-mm pupil increased 3.68 and 19 times, respectively, after the treatments. The OZ area showed a strong correlation with C40 (r=-0.49, p<0.05) and a very strong correlation with C60 (r=0.78, p<0.01). The OZ, as well as the TZ, areas did not correlate with baseline refraction. The increase in the eye's positive SA after ortho-k is the major factor responsible for the decreased retinal optical quality of the unaccommodated eye.

Tautomerism in o-hydroxyanilino-1,4-naphthoquinone derivatives: Structure, NMR, HPLC and density functional theoretic investigations

NASA Astrophysics Data System (ADS)

Bhand, Sujit; Patil, Rishikesh; Shinde, Yogesh; Lande, Dipali N.; Rao, Soniya S.; Kathawate, Laxmi; Gejji, Shridhar P.; Weyhermüller, Thomas; Salunke-Gawali, Sunita

2016-11-01

Structure and spectral characteristics of 'Ortho' ((E)-4-hydroxy-2-(2‧-(4‧-R)-hydroxyphenyl)-imino)-naphthalen-1(2H)-one) and 'para' (2-(2‧-(4‧-R)-hydroxyphenyl)-amino)-1,4-naphthoquinone) tautomers of o-hydroxyanilino-1,4-naphthoquinone derivatives (Rdbnd H, 1A; sbnd CH3, 2A; and -Cl, 3A) are investigated using the 1H, 13C, DEPT, gDQCOSY, gHSQCAD NMR, HPLC, cyclic voltammetry techniques combined with the density functional theory. The compound 2A crystallizes in monoclinic space group P21/c. wherein the polymer chain is facilitated via Osbnd H⋯O and Csbnd H⋯O intermolecular hydrogen bonding. Marginal variations in bond distances in quinonoid and aminophenol moieties render structural flexibility to these compounds those in solution exist as exist in 'ortho - para' tautomers. 1H and 13C NMR spectra in DMSO-d6 showed two sets of peaks in all compounds; whereas only the para tautomer of for 1A and 2A, the para tautomer is predominant in CD3CN solution. Further the ortho-para interconversion is accompanied by a large up-field signals for C(3)sbnd H(3) in their 1H and 13C NMR spectra. These inferences are corroborated by the density functional theoretic calculations.

Detailed Analysis of Near-IR Water (H2O) Emission in Comet C/2014 Q2 (Lovejoy) with the GIANO/TNG Spectrograph

NASA Astrophysics Data System (ADS)

Faggi, S.; Villanueva, G. L.; Mumma, M. J.; Brucato, J. R.; Tozzi, G. P.; Oliva, E.; Massi, F.; Sanna, N.; Tozzi, A.

2016-10-01

We observed the Oort cloud comet C/2014 Q2 (Lovejoy) on 2015 January 31 and February 1 and 2 at a heliocentric distance of 1.3 au and geocentric distance of 0.8 au during its approach to the Sun. Comet Lovejoy was observed with GIANO, the near-infrared high-resolution spectrograph mounted at the Nasmyth-A focus of the TNG (Telescopio Nazionale Galileo) telescope in La Palma, Canary Islands, Spain. We detected strong emissions of radical CN and water, along with many emission features of unidentified origin, across the 1-2.5 μm region. Spectral lines from eight ro-vibrational bands of H2O were detected, six of them for the first time. We quantified the water production rate [Q(H2O), (3.11 ± 0.14) × 1029 s-1] by comparing the calibrated line fluxes with the Goddard full non-resonance cascade fluorescence model for H2O. The production rates of ortho-water [Q(H2O)ORTHO, (2.33 ± 0.11) × 1029 s-1] and para-water [Q(H2O)PARA, (0.87 ± 0.21) × 1029 s-1] provide a measure of the ortho-to-para ratio (2.70 ± 0.76)). The confidence limits are not small enough to provide a critical test of the nuclear spin temperature.

Detailed Analysis of Near-IR Water (H2O) Emission in Comet C/2014 Q2 (LOVEJOY) with the GIANO/TNG Spectrograph

NASA Technical Reports Server (NTRS)

Faggi, S.; Villanueva, G. L.; Mumma, M. J.; Brucato, J.R.; Tozzi, G. P.; Oliva, E.; Massi, F.; Sanna, N.; Tozzi, A.

2016-01-01

We observed the Oort cloud comet C/2014 Q2 (Lovejoy) on 2015 January 31 and February 1 and 2 at a heliocentric distance of 1.3 au and geocentric distance of 0.8 au during its approach to the Sun. Comet Lovejoy was observed with GIANO, the near-infrared high-resolution spectrograph mounted at the Nasmyth-A focus of the TNG (Telescopio Nazionale Galileo) telescope in La Palma, Canary Islands, Spain. We detected strong emissions of radical CN and water, along with many emission features of unidentified origin, across the 1-2.5 micron region. Spectral lines from eight ro-vibrational bands of H2O were detected, six of them for the first time. We quantified the water production rate [Q(H2O), (3.11+/- 0.14) x 10(exp 29)/s] by comparing the calibrated line fluxes with the Goddard full non-resonance cascade fluorescence model for H2O. The production rates of ortho-water [Q(H2O)ORTHO, (2.33+/- 0.11) x 10(exp 29)/s] and para-water [Q(H2O)PARA, (0.87+/-0.21) x 10(exp 29)/s] provide a measure of the ortho-to-para ratio (2.70+/- 0.76)). The confidence limits are not small enough to provide a critical test of the nuclear spin temperature.

A second ortho­rhom­bic polymorph of (Z)-3-(9-anthr­yl)-1-(2-thien­yl)prop-2-en-1-one1

PubMed Central

Chantrapromma, Suchada; Suwunwong, Thitipone; Boonnak, Nawong; Fun, Hoong-Kun

2010-01-01

The title heteroaryl chalcone, C21H14OS, is a second ortho­rhom­bic polymorph which crystallizes in the space group P212121. The structure was previously reported [Fun et al. (2009 ▶). Acta Cryst. E65, o2168-o2169] in the space group Pna21. The bond distances and angles are similar in both structures. In contrast, the overall crystal packing is different from that in the first ortho­rhom­bic Pna21 polymorph in which mol­ecules were stacked into columns along the b axis and the thio­phene units of two adjacent columns were stacked in a head to tail fashion. In the present polymorph, mol­ecules are found to dimerize through a weak S⋯S inter­action [3.6513 (7) Å] and these dimers are arranged into sheets parallel to the bc plane. There are no classical hydrogen bonds in the packing which features short C⋯O [3.2832 (2)–3.6251 (9) Å], C⋯S [3.4879 (17)–3.6251 (19) Å] and S⋯O [2.9948 (16) Å] contacts, together with C—H⋯π inter­actions. Similar contacts were found in the other polymorph. PMID:21579743

OnpA, an Unusual Flavin-Dependent Monooxygenase Containing a Cytochrome b5 Domain

PubMed Central

Xiao, Yi; Liu, Ting-Ting; Dai, Hui; Zhang, Jun-Jie; Liu, Hong; Tang, Huiru; Leak, David J.

2012-01-01

ortho-Nitrophenol 2-monooxygenase (EC 1.14.13.31) from Alcaligenes sp. strain NyZ215 catalyzes monooxygenation of ortho-nitrophenol to form catechol via ortho-benzoquinone. Sequence analysis of this onpA-encoded enzyme revealed that it contained a flavin-binding monooxygenase domain and a heme-binding cytochrome b5 domain. OnpA was purified to homogeneity as a His-tagged protein and was considered a monomer, as determined by gel filtration. FAD and heme were identified by high-performance liquid chromatography (HPLC) and HPLC-mass spectrometry (HPLC-MS) as cofactors in this enzyme, and quantitative analysis indicated that 1 mol of the purified recombinant OnpA contained 0.66 mol of FAD and 0.20 mol of heme. However, the enzyme activity of OnpA was increased by 60% and 450% after addition of FAD and hemin, respectively, suggesting that the optimal stoichiometry was 1:1:1. In addition, site-directed mutagenesis experiments confirmed that two highly conserved histidines located in the cytochrome b5 domain were associated with binding of the heme, and the cytochrome b5 domain was involved in the OnpA activity. These results indicate that OnpA is an unusual FAD-dependent monooxygenase containing a fused cytochrome b5 domain that is essential for its activity. Therefore, we here demonstrate a link between cytochrome b5 and flavin-dependent monooxygenases. PMID:22267507

Hydroxytyrosol inhibits hydrogen peroxide-induced apoptotic signaling via labile iron chelation.

PubMed

Kitsati, Natalia; Mantzaris, Michalis D; Galaris, Dimitrios

2016-12-01

Although it is known that Mediterranean diet plays an important role in maintaining human health, the underlying molecular mechanisms remain largely unknown. The aim of this investigation was to elucidate the potential role of ortho-dihydroxy group containing natural compounds in H 2 O 2 -induced DNA damage and apoptosis. For this purpose, the main phenolic alcohols of olive oil, namely hydroxytyrosol and tyrosol, were examined for their ability to protect cultured cells under conditions of oxidative stress. A strong correlation was observed between the ability of hydroxytyrosol to mitigate intracellular labile iron level and the protection offered against H 2 O 2 -induced DNA damage and apoptosis. On the other hand, tyrosol, which lacks the ortho-dihydroxy group, was ineffective. Moreover, hydroxytyrosol (but not tyrosol), was able to diminish the late sustained phase of H 2 O 2 -induced JNK and p38 phosphorylation. The derangement of intracellular iron homeostasis, following exposure of cells to H 2 O 2 , played pivotal role both in the induction of DNA damage and the initiation of apoptotic signaling. The presented results suggest that the protective effects exerted by ortho-dihydroxy group containing dietary compounds against oxidative stress-induced cell damage are linked to their ability to influence changes in the intracellular labile iron homeostasis. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Longitudinal nuclear spin relaxation of ortho- and para-hydrogen dissolved in organic solvents.

PubMed

Aroulanda, Christie; Starovoytova, Larisa; Canet, Daniel

2007-10-25

The longitudinal relaxation time of ortho-hydrogen (the spin isomer directly observable by NMR) has been measured in various organic solvents as a function of temperature. Experimental data are perfectly interpreted by postulating two mechanisms, namely intramolecular dipolar interaction and spin-rotation, with activation energies specific to these two mechanisms and to the solvent in which hydrogen is dissolved. This permits a clear separation of the two contributions at any temperature. Contrary to the self-diffusion coefficients at a given temperature, the rotational correlation times extracted from the dipolar relaxation contribution do not exhibit any definite trend with respect to solvent viscosity. Likewise, the spin-rotation correlation time obeys Hubbard's relation only in the case of hydrogen dissolved in acetone-d6, yielding in that case a spin-rotation constant in agreement with literature data. Concerning para-hydrogen, which is NMR-silent, the only feasible approach is to dissolve para-enriched hydrogen in these solvents and to follow the back-conversion of the para-isomer into the ortho-isomer. Experimentally, this conversion has been observed to be exponential, with a time constant assumed to be the relaxation time of the singlet state (the spin state of the para-isomer). A theory, based on intermolecular dipolar interactions, has been worked out for explaining the very large values of these relaxation times which appear to be solvent-dependent.

H6+ in irradiated solid para-hydrogen and its decay dynamics: reinvestigation of quartet electron paramagnetic resonance lines assigned to H2-.

PubMed

Kumada, Takayuki; Tachikawa, Hiroto; Takayanagi, Toshiyuki

2005-03-07

The quartet electron paramagnetic resonance (EPR) lines observed in gamma- and X-ray irradiated solid para-H2, which have previously been assigned to H2-, are reinvestigated. We have reassigned the quartet lines to H6 rather than H2- mainly due to comparison of experimentally obtained EPR parameters to theoretical results. Based on the new assignment, trapping site, rotation, ortho-para conversion, quantum diffusion and isotope effect of H+ have been reinterpreted by the precise reanalysis as follows. The H6+ ion is composed of the collinearly aligned H2+ core at the center and two H2 rotors at both ends, occupies a single substitutional site, and has a precession motion around a crystalline axis with the angle of approximately 57 degrees. The ortho-para conversion of H2+ core of H6+ is completed within the time-scale of hours, whereas ortho-H2 molecules near H6+ convert much faster. H6+ diffuses quantum mechanically by the repetition of H6+ + H2 --> H2 + H6+ reaction. The diffusion terminates by the reaction, H6(+) + HD --> H5D(+) + H2, with a HD impurity contained in the para-H2 sample at natural abundance. Finally, we will propose a possible reason why H6+ is produced instead of H3+ in the irradiated solid H2.

Suggestion for search of cyclopropenone (c-C3H2O) in a cosmic object

NASA Astrophysics Data System (ADS)

Sharma, M. K.; Sharma, M.; Chandra, S.

2017-03-01

Following Minimum Energy Principle, out of the three isomers of chemical formula C3H2O, the cyclopropenone (c-C3H2O) is the most stable and therefore may be the most abundant and easily detectable in a cosmic object. The cyclopropenone is detected in Sgr B2(N). Owing to half-spin of each of two hydrogen atoms, the c-C3H2O has two distinct ortho and para species. Using the rotational and centrifugal distortion constants along with the electric dipole moment, we have calculated energies of 100 rotational levels of each of the ortho and para species of c-C3H2O and the Einstein A-coefficients for radiative transitions between the levels. The values of Einstein A-coefficients along with the scaled values for collisional rate coefficients are used for solving a set of statistical equilibrium equations coupled with the equations of radiative transfer. Brightness temperatures of seven rotational transitions of each of the ortho and para species of c-C3H2O are investigated. Out of fourteen transitions, seven are found to show anomalous absorption and rest seven are found to show emission feature. We find that the transitions 110 -111 (1.544 GHz) may play important role in identification of cyclopropenone in a cosmic object.

Adiabatic Variational Theory for Cold Atom-Molecule Collisions: Application to a Metastable Helium Atom Colliding with ortho- and para-Hydrogen Molecules.

PubMed

Pawlak, Mariusz; Shagam, Yuval; Klein, Ayelet; Narevicius, Edvardas; Moiseyev, Nimrod

2017-03-16

We recently developed an adiabatic theory for cold molecular collision experiments. In our previous application of this theory ( Pawlak, M.; et al. J. Chem. Phys. 2015 , 143 , 074114 ), we assumed that during the experiment the collision of an atom with a diatom takes place when the diatom is in the ground rotational state and is located in a plane. In this paper, we present how the variational approach of the adiabatic theory for low-temperature collision experiments can be used for the study a 5D collision between the atom and the diatomic molecule with no limitations on its rotational quantum states and no plane restrictions. Moreover, we show here the dramatic differences in the measured reaction rates of He(2 3 S 1 ) + ortho/para-H 2 → He(1s 2 ) + ortho/para-H 2 + + e - resulting from the anisotropic long-range interactions in the reaction. In collisions of metastable helium with molecular hydrogen in the ground rotational state, the isotropic potential term dominates the dynamics. When the collision is with molecular hydrogen in the first excited rotational state, the nonisotropic interactions play an important role in the dynamics. The agreement of our results with the latest experimental findings ( Klein , A. ; et al. Nat. Phys. 2017 , 13 , 35 - 38 ) is very good.

Possible mechanisms for the relative efficacies of ortho-phthalaldehyde and glutaraldehyde against glutaraldehyde-resistant Mycobacterium chelonae.

PubMed

Walsh, S E; Maillard, J Y; Russell, A D; Hann, A C

2001-07-01

This investigation compared glutaraldehyde (GTA)-sensitive and -resistant strains of Mycobacterium chelonae and examined the effects of pretreatment of GTA-sensitive and -resistant strains of Myco. chelonae with chemical agents that interfere with cell wall synthesis. When exposed to 2% (v/v) GTA at 25 degrees C, GTA-resistant strains of Myco. chelonae dried on to glass carriers were not inactivated to any significant extent. By contrast, GTA-sensitive strains of Myco. chelonae and a strain of Myco. terrae suffered a > 6 log reduction in viability in 5 min. However, ortho-phthalaldehyde (OPA; 0.5% w/v) achieved a corresponding inactivation against two GTA-resistant strains within 5-10 and 10-20 min, respectively. Electron microscopy, using a non-aldehyde fixation process and also negative staining, failed to detect any extensive changes in GTA-sensitive and -resistant cultures exposed to GTA or OPA. Thin-layer chromatography was unsuccessful in detecting differences between GTA-resistant and -sensitive strains of Myco. chelonae. However, pretreatment of GTA-resistant cells with mycobacterial cell wall synthesis inhibitors increased their subsequent susceptibility further to OPA but not to GTA. Ortho-phthalaldehyde is an effective new biocidal agent that, at its in-use concentration, is rapidly bactericidal to non-sporulating bacteria, including GTA-sensitive and -resistant mycobacteria. Pretreatment of GTA-resistant cells with mycobacterial cell wall synthesis inhibitors increased their subsequent susceptibility to OPA but not to GTA.

Synthesis, anticancer and antibacterial activity of salinomycin N-benzyl amides.

PubMed

Antoszczak, Michał; Maj, Ewa; Napiórkowska, Agnieszka; Stefańska, Joanna; Augustynowicz-Kopeć, Ewa; Wietrzyk, Joanna; Janczak, Jan; Brzezinski, Bogumil; Huczyński, Adam

2014-11-25

A series of 12 novel monosubstituted N-benzyl amides of salinomycin (SAL) was synthesized for the first time and characterized by NMR and FT-IR spectroscopic methods. Molecular structures of three salinomycin derivatives in the solid state were determined using single crystal X-ray method. All compounds obtained were screened for their antiproliferative activity against various human cancer cell lines as well as against the most problematic bacteria strains such as methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE), and Mycobacterium tuberculosis. Novel salinomycin derivatives exhibited potent anticancer activity against drug-resistant cell lines. Additionally, two N-benzyl amides of salinomycin revealed interesting antibacterial activity. The most active were N-benzyl amides of SAL substituted at -ortho position and the least anticancer active derivatives were those substituted at the -para position.

Transition metal catalyzed manipulation of non-polar carbon–hydrogen bonds for synthetic purpose

PubMed Central

MURAI, Shinji

2011-01-01

The direct addition of ortho C–H bonds in various aromatic compounds such as ketones, esters, imines, imidates, nitriles, and aldehydes to olefins and acetylenes can be achieved with the aid of transition metal catalysts. The ruthenium catalyzed reaction is usually highly efficient and useful as a general synthetic method. The coordination to the metal center by a heteroatom in a directing group such as carbonyl and imino groups in aromatic compounds is the key step in this process. Mechanistically, the reductive elimination to form a C–C bond is the rate-determining step, while the C–H bond cleavage step is not. PMID:21558759

Synthesis of Dibenzo[h,rst]pentaphenes and Dibenzo[fg,qr]pentacenes by the Chemoselective C-O Arylation of Dimethoxyanthraquinones.

PubMed

Suzuki, Yusuke; Yamada, Kohei; Watanabe, Kentaro; Kochi, Takuya; Ie, Yutaka; Aso, Yoshio; Kakiuchi, Fumitoshi

2017-07-21

A convenient method for the syntheses of dibenzo[h,rst]pentaphenes and dibenzo[fg,qr]pentacenes via the ruthenium-catalyzed chemoselective C-O arylation of 1,4- and 1,5-dimethoxyanthraquinones is described. Dimethoxyanthraquinones reacted selectively with arylboronates at the ortho C-O bonds to give diarylation products. An efficient two-step procedure consisting of a Corey-Chaykofsky reaction and subsequent dehydrative aromatization afforded derivatives of dibenzo[h,rst]pentaphenes and dibenzo[fg,qr]pentacenes. Hole-transporting characteristics were observed for a device with a bottom-contact configuration that was fabricated from one of these polycyclic aromatic hydrocarbons.

Structural phase transition at high temperatures in solid molecular hydrogen and deuterium

NASA Astrophysics Data System (ADS)

Cui, T.; Takada, Y.; Cui, Q.; Ma, Y.; Zou, G.

2001-07-01

We study the effect of temperature up to 1000 K on the structure of dense molecular para-hydrogen (p-H2) and ortho-deuterium (o-D2), using the path-integral Monte Carlo method. We find a structural phase transition from orientationally disordered hexagonal close packed (hcp) to an orthorhombic structure of Cmca symmetry before melting. The transition is basically induced by thermal fluctuations, but quantum fluctuations of protons (deuterons) are important in determining the transition temperature through effectively hardening the intermolecular interaction. We estimate the phase line between hcp and Cmca phases as well as the melting line of the Cmca solid.

Optimizing digital elevation models (DEMs) accuracy for planning and design of mobile communication networks

NASA Astrophysics Data System (ADS)

Hassan, Mahmoud A.

2004-02-01

Digital elevation models (DEMs) are important tools in the planning, design and maintenance of mobile communication networks. This research paper proposes a method for generating high accuracy DEMs based on SPOT satellite 1A stereo pair images, ground control points (GCP) and Erdas OrthoBASE Pro image processing software. DEMs with 0.2911 m mean error were achieved for the hilly and heavily populated city of Amman. The generated DEM was used to design a mobile communication network resulted in a minimum number of radio base transceiver stations, maximum number of covered regions and less than 2% of dead zones.

77 FR 49793 - Ortho-Phthalaldehyde; Receipt of Application for Emergency Exemption, Solicitation of Public Comment

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-17

... parapaucimobilis, Stenotrophomonas maltophilia, Methylobacterium extorquens, and unidentified gram negative rods..., Stenotrophomonas maltophilia, Methylobacterium extorquens, and unidentified gram negative rods. Information in...

Coordination nano-space as stage of hydrogen ortho-para conversion.

PubMed

Kosone, Takashi; Hori, Akihiro; Nishibori, Eiji; Kubota, Yoshiki; Mishima, Akio; Ohba, Masaaki; Tanaka, Hiroshi; Kato, Kenichi; Kim, Jungeun; Real, José Antonio; Kitagawa, Susumu; Takata, Masaki

2015-07-01

The ability to design and control properties of nano-sized space in porous coordination polymers (PCPs) would provide us with an ideal stage for fascinating physical and chemical phenomena. We found an interconversion of nuclear-spin isomers for hydrogen molecule H2 adsorbed in a Hofmann-type PCP, {Fe(pz)[Pd(CN)4]} (pz=pyrazine), by the temperature dependence of Raman spectra. The ortho (o)-para (p) conversion process of H2 is forbidden for an isolated molecule. The charge density study using synchrotron radiation X-ray diffraction reveals the electric field generated in coordination nano-space. The present results corroborate similar findings observed on different systems and confirm that o-p conversion can occur on non-magnetic solids and that electric field can induce the catalytic hydrogen o-p conversion.

Exo-pi-bonding to an ortho-carborane hypercarbon atom: systematic icosahedral cage distortions reflected in the structures of the fluoro-, hydroxy- and amino-carboranes, 1-X-2-Ph-1,2-C2B10H10 (X=F, OH or NH2) and related anions.

PubMed

Boyd, Lynn A; Clegg, William; Copley, Royston C B; Davidson, Matthew G; Fox, Mark A; Hibbert, Thomas G; Howard, Judith A K; Mackinnon, Angus; Peace, Richard J; Wade, Kenneth

2004-09-07

The structures of derivatives of phenyl-ortho-carborane bearing on the second cage hypercarbon atom a pi-donor substituent (F, OH, O-, NH2, NH- and CH2-) were investigated by NMR, X-ray crystallography and computational studies. The molecular structures of these compounds, notably their cage C1-C2 distances and the orientations of their pi-donor substituents (OH, NH2, NH- and CH2-) show remarkable and systematic variations with the degree of exo pi-bonding, which varies as expected with the pi-donor characteristics of the substituent.

The ortho-para H2 distribution on Uranus: Constraints from the collision-induced 3-0 dipole band and 4-0 S(0) and S(1) quadrupole line profiles

NASA Technical Reports Server (NTRS)

Baines, K. H.; Bergstralh, J. T.

1986-01-01

Recent high quality spectral observations have allowed the derivation of constraints on the atmospheric structure of Uranus. The present analysis, which is based on the detailed modeling of a broadband geometric albedo spectrum and high resolution observations of the H2 4-0 quadrupole and 6818.9-A CH4 features, yields (1) a family of models which parameterize an upper tropospheric haze layer, (2) a lower, optically infinite cloud at a given pressure level, (3) the cloud-level methane molar fraction, and (4) the mean ortho/para ratio in the visible atmosphere. The single scattering albedo of atmospheric aerosols exhibits a steep darkening between 5890 and 6040 A.

A local proton source enhances CO2 electroreduction to CO by a molecular Fe catalyst.

PubMed

Costentin, Cyrille; Drouet, Samuel; Robert, Marc; Savéant, Jean-Michel

2012-10-05

Electrochemical conversion of carbon dioxide (CO(2)) to carbon monoxide (CO) is a potentially useful step in the desirable transformation of the greenhouse gas to fuels and commodity chemicals. We have found that modification of iron tetraphenylporphyrin through the introduction of phenolic groups in all ortho and ortho' positions of the phenyl groups considerably speeds up catalysis of this reaction by the electrogenerated iron(0) complex. The catalyst, which uses one of the most earth-abundant metals, manifests a CO faradaic yield above 90% through 50 million turnovers over 4 hours of electrolysis at low overpotential (0.465 volt), with no observed degradation. The basis for the enhanced activity appears to be the high local concentration of protons associated with the phenolic hydroxyl substituents.

H and H2 NMR properties in amorphous hydrogenated silicon (a-Si:H)

NASA Astrophysics Data System (ADS)

Lee, Sook

1986-07-01

It is shown that the basic NMR properties of ortho-H2 molecules with a rotational angular momentum J and a spin angular momentum I under the influence of a completely asymmetric crystalline field in an amorphous matrix can be described by an effective nuclear spin Hamiltonian which contains only the nuclear spin angular momentum operators (Ii), but is independent of the molecular rotational angular momentum operators (Ji). By directly applying the existing magnetic-resonance theories to this effective nuclear spin Hamiltonian, a simple description is presented for various static and dynamic NMR properties of the ortho-H2 NMR centers in amorphous hydrogenated silicon (a-Si:H), thereby resolving many difficulties and uncertainties encountered in understanding and explaining the H and H2 NMR observations in a-Si:H.

Measuring the continuity of diffusion barriers on porous films using γ-ray energy spectra of escaping positronium

NASA Astrophysics Data System (ADS)

Xu, Jun; Mills, Allen P.; Case, Carlye

2005-08-01

Diffusion barriers for capping porous low dielectric constant films are important for preventing metal migration into a semiconductor circuit. Using the fact that positrons implanted into a porous dielectric form ortho-positronium (o-Ps) copiously, Gidley et al. [D. W. Gidley, W. F. Frieze, T. L. Dull, J. Sun, A. F. Yee, C. V. Nguyen, and D. Y. Yoon, Appl. Phys. Lett. 76, 1282 (2000)], have been able to measure open area fractions as low as 10-5 in porous dielectric film barrier layers from the increase in the ortho-positronium lifetime and intensity associated with positronium escape into vacuum. We demonstrate that it is possible to obtain comparable sensitivities by measuring the gamma-ray energy spectrum of the escaping positronium.

Production and characterization of para-hydrogen gas for matrix isolation infrared spectroscopy

NASA Astrophysics Data System (ADS)

Sundararajan, K.; Sankaran, K.; Ramanathan, N.; Gopi, R.

2016-08-01

Normal hydrogen (n-H2) has 3:1 ortho/para ratio and the production of enriched para-hydrogen (p-H2) from normal hydrogen is useful for many applications including matrix isolation experiments. In this paper, we describe the design, development and fabrication of the ortho-para converter that is capable of producing enriched p-H2. The p-H2 thus produced was probed using infrared and Raman techniques. Using infrared measurement, the thickness and the purity of the p-H2 matrix were determined. The purity of p-H2 was determined to be >99%. Matrix isolation infrared spectra of trimethylphosphate (TMP) and acetylene (C2H2) were studied in p-H2 and n-H2 matrices and the results were compared with the conventional inert matrices.

Collisional excitation of HC3N by para- and ortho-H2

NASA Astrophysics Data System (ADS)

Faure, Alexandre; Lique, François; Wiesenfeld, Laurent

2016-08-01

New calculations for rotational excitation of cyanoacetylene by collisions with hydrogen molecules are performed to include the lowest 38 rotational levels of HC3N and kinetic temperatures to 300 K. Calculations are based on the interaction potential of Wernli et al. whose accuracy is checked against spectroscopic measurements of the HC3N-H2 complex. The quantum coupled-channel approach is employed and complemented by quasi-classical trajectory calculations. Rate coefficients for ortho-H2 are provided for the first time. Hyperfine resolved rate coefficients are also deduced. Collisional propensity rules are discussed and comparisons between quantum and classical rate coefficients are presented. This collisional data should prove useful in interpreting HC3N observations in the cold and warm ISM, as well as in protoplanetary discs.

Dynamics of hydrogen guests in ice XVII nanopores

NASA Astrophysics Data System (ADS)

del Rosso, Leonardo; Celli, Milva; Colognesi, Daniele; Rudić, Svemir; English, Niall J.; Burnham, Christian J.; Ulivi, Lorenzo

2017-11-01

The present high-resolution inelastic neutron scattering experiment on ice XVII, containing molecular hydrogen with a different ortho/para ratio, allows one to assign the H2 motion spectral bands to rotational and center-of-mass translational transitions of either para- or ortho-H2. Due to its structure, ice XVII confines H2 molecules to move in spiral channels of molecular size. Reported data demonstrate that H2 molecules rotate almost freely in these nanometric channels, though showing larger perturbation than in clathrate hydrates, and perform a translational motion exhibiting two low-frequency excitations. The agreement between the experimental spectra and the corresponding molecular dynamics results clearly enables one to portray a picture of the confined motions of a hydrophobic guest within a metastable ice framework, i.e., ice XVII.

Dendronized fullerene-porphyrin conjugates in ortho, meta, and para positions: a charge-transfer assay.

PubMed

Krokos, Evangelos; Schubert, Christina; Spänig, Fabian; Ruppert, Michaela; Hirsch, Andreas; Guldi, Dirk M

2012-06-01

The physicochemical characterization, that is, ground and excited state, of a new series of dendronized porphyrin/fullerene electron donor-acceptor conjugates in nonaqueous and aqueous environments is reported. In contrast to previous work, we detail the charge-separation and charge-recombination dynamics in zinc and copper metalloporphyrins as a function of first- and second-generation dendrons as well as a function of ortho, meta, and para substitution. Both have an appreciable impact on the microenvironments of the redox-active constituents, namely the porphyrins and the fullerenes. As a matter of fact, the resulting charge-transfer dynamics were considerably impacted by the interplay between the associated forces that reach from dendron-induced shielding to dipole-charge interactions. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reactions of ortho-lithiophenyl (-hetaryl) isocyanides with carbonyl compounds: rearrangements of 2-metalated 4H-3,1-benzoxazines.

PubMed

Lygin, Alexander V; de Meijere, Armin

2009-06-19

ortho-Lithiophenyl (-hetaryl) isocyanides react with aldehydes and ketones providing isocyanoalcohols 8 (36-89%, nine examples), 4H-3,1-benzoxazines 9 (45-78%, six examples) or, after two types of rearrangements, isobenzofuran-1(3H)-imines (iminophthalanes) 18 (52-75%, four examples), or indolin-2-ones 19 (42-79%, two examples), depending on the reaction conditions and substitution patterns. Isocyanoalcohols 8, in turn, were converted to 9 or 18 under Cu(I) catalysis (66-86%, eight examples). 4H-3,1-Benzoxazin-4-ones 39-Nu and isatoic anhydride 40 were obtained by the reaction of 2 with carbon dioxide followed by trapping of the lithiated intermediate with iodine and subsequent reactions with nucleophiles (45-60%, three examples).

New diamine hardeners for epoxies

NASA Technical Reports Server (NTRS)

Bell, V. L.; St. Clair, T. L.

1977-01-01

Stronger amine-cured polyepoxides can be obtained by using those diaminobenzophenones and diaminodiphenylmethanes that have amine groups located at ortho or meta positions to carbonyl or methylene groups joining two benzene rings.

Types of Contact Lenses

MedlinePlus

... Consumer Devices Consumer Products Contact Lenses Types of Contact Lenses Share Tweet Linkedin Pin it More sharing ... Orthokeratology (Ortho-K) Decorative (Plano) Contact Lenses Soft Contact Lenses Soft contact lenses are made of soft, ...

Exposure of dioxin-like chemicals in participants of the Anniston community health survey follow-up.

PubMed

Yang, Eric; Pavuk, Marian; Sjödin, Andreas; Lewin, Michael; Jones, Richard; Olson, Jim; Birnbaum, Linda

2018-05-12

The 2014 follow-up of the Anniston Community Health Survey (ACHS II) consisted of 338 surviving participants from the 2005-2007 baseline study (ACHS) who had previous polychlorinated biphenyl (PCB) measurements, were not pregnant, and were not institutionalized. Questionnaires and blood samples provided the demographic, personal history, and chemical concentration data of the Anniston residents. Approximately 51% of participants were African American, 72% were female, and the mean age was 63 years old. The objectives of this study were to provide an exposure assessment of dioxin-like chemicals in the ACHS II participants and compare the measurements with the general United States (U.S.) population via the National Health and Nutrition Examination Survey (NHANES). Stratified analyses revealed significantly higher average total dioxin toxic equivalencies (TEQs) among African Americans compared to Whites (33.1 vs. 19.2 pg/g lipid), and in females compared to males (29.8 vs. 17.0 pg/g lipid). When adjusting for age, sex, and race in linear regression, we found ACHS II participants to have significantly higher total dioxin TEQ than the general 2014 U.S. population that we estimated for using half-life and NHANES 2003/04 data (most recent NHANES individual samples data), by 16.7 pg/g lipid. Principal component analyses showed that non-ortho and mono-ortho PCBs were separated from the other dioxin-like chemicals among the Anniston residents, whereas the chemicals were all clustered together for estimated NHANES 2014. The concentrations of dioxin-like chemicals, especially non-ortho and mono-ortho PCBs, in Anniston residents who resided near the former PCB production plant were higher than those in the general U.S. Although data strongly supported this difference, these inferences are limited because NHANES 2013/14 data were unavailable and we used estimated NHANES 2014 levels that we imputed from NHANES 2003/04 data in conjunction with half-life values estimated from Milbrath et al., 2009. Copyright © 2018. Published by Elsevier B.V.

Photochemically Synthesized Polyimides

NASA Technical Reports Server (NTRS)

Meador, Michael A.; Tyson, Daniel S.

2008-01-01

An alternative to the conventional approach to synthesis of polyimides involves the use of single monomers that are amenable to photopolymerization. Heretofore, the synthesis of polyimides has involved multiple-monomer formulations and heating to temperatures that often exceed 250 C. The present alternative approach enables synthesis under relatively mild conditions that can include room temperature. The main disadvantages of the conventional approach are the following: Elevated production temperatures can lead to high production costs and can impart thermal stresses to the final products. If the proportions of the multiple monomeric ingredients in a given batch are not exactly correct, the molecular weight and other physical properties of the final material could be reduced from their optimum or desired values. To be useful in the alternative approach, a monomer must have a molecular structure tailored to exploit Diels-Alder trapping of a photochemically generated ortho-quinodimethane. (In a Diels-Alder reaction, a diene combines with a dienophile to form molecules that contain six-membered rings.) In particular, a suitable monomer (see figure) contains ortho-methylbenzophenone connected to a dienophile (in this case, a maleimide) through a generic spacer group. Irradiation with ultraviolet light gives rise to a photochemical intermediate the aforementioned ortho-quinodimethane from the ortho-methylbenzophenone. This group may react with the dienophile on another such monomer molecule to produce an oligomer that, in turn may react in a stepgrowth manner to produce a polyimide. This approach offers several advantages in addition to those mentioned above: The monomer can be stored for a long time because it remains unreactive until exposed to light. Because the monomer is the only active starting ingredient, there is no need for mixing, no concern for ensuring correct proportions of monomers, and the purity of the final product material is inherently high. The use of solvents is optional: The synthesis can be performed using the neat monomer or the monomer mixed with one or more solvent(s) in dilute or concentrated solution. The solubility of the monomer and the physical and chemical properties of the final polymer can be tailored through selection of the spacer group.

H2D(+) observations give an age of at least one million years for a cloud core forming Sun-like stars.

PubMed

Brünken, Sandra; Sipilä, Olli; Chambers, Edward T; Harju, Jorma; Caselli, Paola; Asvany, Oskar; Honingh, Cornelia E; Kamiński, Tomasz; Menten, Karl M; Stutzki, Jürgen; Schlemmer, Stephan

2014-12-11

The age of dense interstellar cloud cores, where stars and planets form, is a crucial parameter in star formation and difficult to measure. Some models predict rapid collapse, whereas others predict timescales of more than one million years (ref. 3). One possible approach to determining the age is through chemical changes as cloud contraction occurs, in particular through indirect measurements of the ratio of the two spin isomers (ortho/para) of molecular hydrogen, H2, which decreases monotonically with age. This has been done for the dense cloud core L183, for which the deuterium fractionation of diazenylium (N2H(+)) was used as a chemical clock to infer that the core has contracted rapidly (on a timescale of less than 700,000 years). Among astronomically observable molecules, the spin isomers of the deuterated trihydrogen cation, ortho-H2D(+) and para-H2D(+), have the most direct chemical connections to H2 (refs 8, 9, 10, 11, 12) and their abundance ratio provides a chemical clock that is sensitive to greater cloud core ages. So far this ratio has not been determined because para-H2D(+) is very difficult to observe. The detection of its rotational ground-state line has only now become possible thanks to accurate measurements of its transition frequency in the laboratory, and recent progress in instrumentation technology. Here we report observations of ortho- and para-H2D(+) emission and absorption, respectively, from the dense cloud core hosting IRAS 16293-2422 A/B, a group of nascent solar-type stars (with ages of less than 100,000 years). Using the ortho/para ratio in conjunction with chemical models, we find that the dense core has been chemically processed for at least one million years. The apparent discrepancy with the earlier N2H(+) work arises because that chemical clock turns off sooner than the H2D(+) clock, but both results imply that star-forming dense cores have ages of about one million years, rather than 100,000 years.

Steric hindrance inhibits excited-state relaxation and lowers the extent of intramolecular charge transfer in two-photon absorbing dyes.

PubMed

Stewart, David J; Dalton, Matthew J; Long, Stephanie L; Kannan, Ramamurthi; Yu, Zhenning; Cooper, Thomas M; Haley, Joy E; Tan, Loon-Seng

2016-02-21

The two-photon absorbing dye AF240 [1, (7-benzothiazol-2-yl-9,9-diethylfluoren-2-yl)diphenylamine] is modified by adding bulky alkyl groups to the diphenylamino moiety. Three new compounds are synthesized which have ethyl groups in both ortho positions of each phenyl ring (2), t-butyl groups in one ortho position of each phenyl ring (3), and t-butyl groups in the para position of each phenyl ring (4). The dyes are examined in several aprotic solvents with varying polarity to observe the effects of the sterically hindering bulky groups on the ground and excited-state photophysical properties. While the ground state shows minimal solvent dependence, there is significant dependence on the fluorescence quantum yield and lifetime, as well as the excited-state energy levels. This effect is caused by the formation of an intramolecular charge-transfer (ICT) state, which is observed in the solvents more polar than n-hexane and supported by TD-DFT calculations. Electronic effects of ortho or para alkyl substitution should be similar, yet drastic differences are observed. A red shift in the fluorescence maximum is observed in 4 relative to 1, yet a blue shift occurs in 2 and 3 because the substituents at the sterically sensitive ortho-positions inhibit excited-state geometric relaxation and result in less ICT character than 1. Coupled with theoretical calculations, the data support a planar ICT (PICT) excited state where the diphenylamino nitrogen in an sp(2)-like geometry is integral with the plane containing the fluorene and benzothiazole moieties. Ultrafast transient absorption experiments show that ICT occurs rapidly (<150 fs) followed by geometric and solvent relaxation in ∼ 1-4 ps to form the PICT or solvent-stabilized ICT (SSICT) state. This relaxation is not observed in non-polar n-hexane because the solvent dependent ICT state energy lies higher than the locally-excited (LE) state. Finally, formation of a triplet state (T1) is only efficiently observed in n-hexane for all four dyes.

Characterization of a Defined 2,3,5,6-Tetrachlorobiphenyl-ortho-Dechlorinating Microbial Community by Comparative Sequence Analysis of Genes Coding for 16S rRNA

PubMed Central

Pulliam Holoman, Tracey R.; Elberson, Margaret A.; Cutter, Leah A.; May, Harold D.; Sowers, Kevin R.

1998-01-01

Defined microbial communities were developed by combining selective enrichment with molecular monitoring of total community genes coding for 16S rRNAs (16S rDNAs) to identify potential polychlorinated biphenyl (PCB)-dechlorinating anaerobes that ortho dechlorinate 2,3,5,6-tetrachlorobiphenyl. In enrichment cultures that contained a defined estuarine medium, three fatty acids, and sterile sediment, a Clostridium sp. was predominant in the absence of added PCB, but undescribed species in the δ subgroup of the class Proteobacteria, the low-G+C gram-positive subgroup, the Thermotogales subgroup, and a single species with sequence similarity to the deeply branching species Dehalococcoides ethenogenes were more predominant during active dechlorination of the PCB. Species with high sequence similarities to Methanomicrobiales and Methanosarcinales archaeal subgroups were predominant in both dechlorinating and nondechlorinating enrichment cultures. Deletion of sediment from PCB-dechlorinating enrichment cultures reduced the rate of dechlorination and the diversity of the community. Substitution of sodium acetate for the mixture of three fatty acids increased the rate of dechlorination, further reduced the community diversity, and caused a shift in the predominant species that included restriction fragment length polymorphism patterns not previously detected. Although PCB-dechlorinating cultures were methanogenic, inhibition of methanogenesis and elimination of the archaeal community by addition of bromoethanesulfonic acid only slightly inhibited dechlorination, indicating that the archaea were not required for ortho dechlorination of the congener. Deletion of Clostridium spp. from the community profile by addition of vancomycin only slightly reduced dechlorination. However, addition of sodium molybdate, an inhibitor of sulfate reduction, inhibited dechlorination and deleted selected species from the community profiles of the class Bacteria. With the exception of one 16S rDNA sequence that had the highest sequence similarity to the obligate perchloroethylene-dechlorinating Dehalococcoides, the 16S rDNA sequences associated with PCB ortho dechlorination had high sequence similarities to the δ, low-G+C gram-positive, and Thermotogales subgroups, which all include sulfur-, sulfate-, and/or iron(III)-respiring bacterial species. PMID:9726883

A 12 month clinical study of bond failures of recycled versus new stainless steel orthodontic brackets.

PubMed

Cacciafesta, Vittorio; Sfondrini, Maria Francesca; Melsen, Birte; Scribante, Andrea

2004-08-01

The purpose of this prospective longitudinal randomized study was to compare the clinical performance of recycled brackets with that of new stainless steel brackets (Orthos). Twenty patients treated with fixed appliances were included in the investigation. Using a 'split-mouth' design, the dentition of each patient was divided into four quadrants. In 11 randomly selected patients, the maxillary left and mandibular right quadrants were bonded with recycled brackets, and the remaining quadrants with new stainless steel brackets. In the other nine patients the quadrants were inverted. Three hundred and ten stainless steel brackets were examined: 156 were recycled and the remaining 154 were new. All the brackets were bonded with a self-cured resin-modified glass ionomer (GC Fuji Ortho). The number, cause, and date of bracket failures were recorded over 12 months. Statistical analysis was performed by means of a paired t-test, Kaplan-Meier survival estimates, and the log-rank test. No statistically significant differences were found between: (a) the total bond failure rate of recycled and new stainless steel brackets; (b) the upper and lower arches; (c) the anterior and posterior segments. These findings demonstrate that recycling metallic orthodontic brackets can be of benefit to the profession, both economically and ecologically, as long as the orthodontist is aware of the various aspects of the recycling methods, and that patients are informed about the type of bracket that will be used for their treatment.

Accuracy of Bolton analysis measured in laser scanned digital models compared with plaster models (gold standard) and cone-beam computer tomography images

PubMed Central

Kim, Jooseong

2016-01-01

Objective The aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models. Methods CBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC). Results Anterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were 0.41 ± 0.305% and 0.45 ± 0.456%, respectively; for anterior Bolton ratios, 0.59 ± 0.520% and 1.01 ± 0.780%, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with < 1.45% discrepancy in the Bolton analysis. Conclusions Laser scanned digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis. PMID:26877978

Information about Musculoskeletal Conditions

MedlinePlus

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Mastcam Stereo Analysis and Mosaics (MSAM)

NASA Astrophysics Data System (ADS)

Deen, R. G.; Maki, J. N.; Algermissen, S. S.; Abarca, H. E.; Ruoff, N. A.

2017-06-01

Describes a new PDART task that will generate stereo analysis products (XYZ, slope, etc.), terrain meshes, and mosaics (stereo, ortho, and Mast/Nav combos) for all MSL Mastcam images and deliver the results to PDS.

Nucleophilic Aromatic Substitution.

ERIC Educational Resources Information Center

Avila, Walter B.; And Others

1990-01-01

Described is a microscale organic chemistry experiment which demonstrates one feasible route in preparing ortho-substituted benzoic acids and provides an example of nucleophilic aromatic substitution chemistry. Experimental procedures and instructor notes for this activity are provided. (CW)

Photochemistry of fluorinated 4-iodophenylnitrenes: matrix isolation and spectroscopic characterization of phenylnitrene-4-yls.

PubMed

Grote, Dirk; Sander, Wolfram

2009-10-02

The photochemistry of a series of fluorinated p-iodophenyl azides 2 has been investigated using matrix isolation IR and EPR spectroscopy. In all cases, the corresponding phenylnitrenes 1 were formed as primary photoproducts. Further irradiation of the nitrenes 1 resulted in the formation of azirines 3, ketenimines 4, and nitreno radicals 5. The yield of 5 depends on the number of ortho fluorine substituents: with two ortho fluorine atoms the highest yield is observed, whereas without fluorine atoms the yield is too low for IR spectroscopic detection. The interconversion between the isomers 1, 3, and 4 proved to be rather complex. If the fluorine atoms are distributed unsymmetrically, two isomers of azirines 3 and ketenimines 4 can be formed. The yields of these isomers depend critically on the irradiation conditions.

A Structure-Activity Study with Aryl Acylamidases

PubMed Central

Villarreal, David T.; Turco, Ronald F.; Konopka, Allan

1994-01-01

We examined the relationship between chemical structure and biodegradability of acylanilide herbicides by using a set of model compounds. Four bacterial isolates (one gram-negative and three gram-positive) that grew on acetanilide were used. These soil isolates cleaved the amide bond of acetanilide via an aryl acylamidase reaction, producing aniline and the organic acid acetate. A series of acetanilide analogs with alkyl substitutions on the nitrogen atom or the aromatic ring were tested for their ability to induce aryl acylamidase activity and act as substrates for the enzyme. The substrate range, in general, was limited to those analogs not disubstituted in the ortho position of the benzene ring or which did not contain an alkyl group on the nitrogen atom. These same N-substituted compounds did not induce enzyme activity either, whereas the ortho-substituted compounds could in some cases. PMID:16349428

Measuring the continuity of diffusion barriers on porous films using {gamma}-ray energy spectra of escaping positronium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu Jun; Mills, Allen P. Jr.; Case, Carlye

2005-08-01

Diffusion barriers for capping porous low dielectric constant films are important for preventing metal migration into a semiconductor circuit. Using the fact that positrons implanted into a porous dielectric form ortho-positronium (o-Ps) copiously, Gidley et al. [D. W. Gidley, W. F. Frieze, T. L. Dull, J. Sun, A. F. Yee, C. V. Nguyen, and D. Y. Yoon, Appl. Phys. Lett. 76, 1282 (2000)], have been able to measure open area fractions as low as 10{sup -5} in porous dielectric film barrier layers from the increase in the ortho-positronium lifetime and intensity associated with positronium escape into vacuum. We demonstrate thatmore » it is possible to obtain comparable sensitivities by measuring the gamma-ray energy spectrum of the escaping positronium.« less

The toxicity of commercial jet oils.

PubMed

Winder, Chris; Balouet, Jean-Christophe

2002-06-01

Jet oils are specialized synthetic oils used in high-performance jet engines. They have an appreciable hazard due to toxic ingredients, but are safe in use provided that maintenance personnel follow appropriate safety precautions and the oil stays in the engine. Aircraft engines that leak oil may expose others to the oils through uncontrolled exposure. Airplanes that use engines as a source of bleed air for cabin pressurization may have this source contaminated by the oil if an engine leaks. Examination of the ingredients of the oil indicates that at least two ingredients are hazardous: N-phenyl-1-naphthylamine (a skin sensitizer) and tricresyl phosphate (a neurotoxicant, if ortho-cresyl isomers are present). Publicly available information such as labels and MSDS understates the hazards of such ingredients and in the case of ortho-cresyl phosphates by several orders of magnitude.

Ortho and para hydrogen dimers on G/SiC(0001): combined STM and DFT study.

PubMed

Merino, P; Švec, M; Martínez, J I; Mutombo, P; Gonzalez, C; Martín-Gago, J A; de Andres, P L; Jelinek, P

2015-01-01

The hydrogen (H) dimer structures formed upon room-temperature H adsorption on single layer graphene (SLG) grown on SiC(0001) are addressed using a combined theoretical-experimental approach. Our study includes density functional theory (DFT) calculations for the full (6√3 × 6√3)R30° unit cell of the SLG/SiC(0001) substrate and atomically resolved scanning tunneling microscopy images determining simultaneously the graphene lattice and the internal structure of the H adsorbates. We show that H atoms normally group in chemisorbed coupled structures of different sizes and orientations. We make an atomic scale determination of the most stable experimental geometries, the small dimers and ellipsoid-shaped features, and we assign them to hydrogen adsorbed in para dimers and ortho dimers configuration, respectively, through comparison with the theory.

Rotationally inelastic cross sections, rates and cooling times for para-H2 +, ortho-D2 + and HD+ in cold helium gas

NASA Astrophysics Data System (ADS)

Vera, Mario Hernández; Schiller, Stephan; Wester, Roland; Gianturco, Francesco Antonio

2017-05-01

In the present work we discuss the dynamical processes guiding the relaxation of the internal rotational energy of three diatomic ions, the para-H2+, the ortho-D2+ and the HD+ in collision with He atoms. The state-changing cross sections and rates for these Molecular Hydrogen Ions (MHIs) are obtained from Close Coupling quantum dynamics calculations and the decay times into their respective ground states are computed by further solving the relevant time-evolution equations. The comparison of the results from the three molecules allows us to obtain a detailed understanding, and a deep insight, on the relative efficiencies of the relaxation processes considered. Contribution to the Topical Issue "Dynamics of Molecular Systems (MOLEC 2016)", edited by Alberto Garcia-Vela, Luis Banares and Maria Luisa Senent.

Structure-activity relationships among substituted N-benzoyl derivatives of phenylalanine and its analogs in a microbial antitumor prescreen I: Derivatives of o-fluoro-DL-phenylalanine.

PubMed

Otani, T T; Briley, M R

1982-02-01

Twelve derivatives of 0-fluoro-dl-phenylalanine containing fluorine, chlorine, methoxy, and nitro radicals in various positions of the aromatic ring of the benzoyl group were prepared and tested in a Lactobacillus casei system. It was found that most substitutions in the benzoyl phenyl ring resulted in a compound exhibiting greater growth-inhibiting activity than the nonsubstituted benzoyl-o-fluorophenylalanine. The greatest activity was observed in the ortho-substituted fluoro compound and the meta- and para-substituted chloro and nitro compounds. With the methoxy group, the position of substitution appeared unimportant, since all three methoxy isomers exhibited essentially equal inhibition. Nitro substitution in the ortho position had a protective effect in that the product was less active than the unsubstituted benzoyl-o-fluoro-dl-phenylalanine.

Measurement of ortho-positronium properties in liquid scintillators

NASA Astrophysics Data System (ADS)

Perasso, S.; Consolati, G.; Franco, D.; Hans, S.; Jollet, C.; Meregaglia, A.; Tonazzo, A.; Yeh, M.

2013-08-01

Pulse shape discrimination in liquid scintillator detectors is a well-established technique for the discrimination of heavy particles from light particles. Nonetheless, it is not efficient in the separation of electrons and positrons, as they give rise to indistinguishable scintillator responses. This inefficiency can be overtaken through the exploitation of the formation of ortho-Positronium (o-Ps), which alters the time profile of light pulses induced by positrons. We characterized the o-Ps properties in the most commonly used liquid scintillators, i.e. PC, PXE, LAB, OIL and PC + PPO. In addition, we studied the effects of scintillator doping on the o-Ps properties for dopants currently used in neutrino experiments, Gd and Nd. Further measurements for Li-loaded and Tl-loaded liquid scintillators are foreseen. We found that the o-Ps properties are suitable for enhancing the electron-positron discrimination.

Sensitometric and image analysis of T-grain film.

PubMed

Thunthy, K H; Weinberg, R

1986-08-01

The new Kodak T-grain film is the result of a new technology that makes fast films with high image resolution. The purpose of the investigation was to determine the sensitometric properties and image quality of a T-grain film (T-Mat G) and also to compare this film with a green-sensitive orthochromatic film (Ortho G) and a blue-sensitive film (XRP). The criteria for film evaluation were relative speed, average contrast, exposure latitude, and image resolution. The results showed that the T-Mat G film is twice as fast as the X-Omat RP film and, one and one-third times as fast as the Ortho G film. T-Mat G also produces high resolution and high contrast. This is contrary to the widely held notion that speed is inversely proportional to image quality.

Chemoenzymatic Synthesis and α-Glucosidase Inhibitory Activity of Dimeric Neolignans Inspired by Magnolol.

PubMed

Pulvirenti, Luana; Muccilli, Vera; Cardullo, Nunzio; Spatafora, Carmela; Tringali, Corrado

2017-05-26

A chemoenzymatic synthesis of a small library of dimeric neolignans inspired by magnolol (1) is reported. The 2-iodoxybenzoic acid (IBX)-mediated regioselective ortho-hydroxylation of magnolol is described, affording the bisphenols 6 and 7. Further magnolol analogues (12, 13, 15-17, 19-23) were obtained from eugenol (3), tyrosol (4), and homovanillic alcohol (5), through horseradish peroxidase (HRP)-mediated oxidative coupling and regioselective ortho-hydroxylation or ortho-demethylation in the presence of IBX, followed by reductive treatment with Na 2 S 2 O 4 . A chemoselective protection/deprotection of the alcoholic group of 4 and 5 was carried out by lipase-mediated acetylation/deacetylation. The dimeric neolignans, together with 1 and honokiol (2), were evaluated as inhibitors of yeast α-glucosidase, in view of their possible utilization and optimization as antidiabetic drugs. The synthetic analogues of magnolol showed a strong inhibitory activity with IC 50 values in the range 0.15-4.1 μM, much lower than those of honokiol and the reference compounds quercetin and acarbose. In particular, a very potent inhibitory activity, with an IC 50 of 0.15 μM, was observed for 1,1'-dityrosol-8,8'-diacetate (15), and comparable inhibitory activities were also shown by bisphenols 6 (0.49 μM), 13 (0.50 μM), and 22 (0.86 μM). A kinetic study showed that 15 acts as a competitive inhibitor, with a K i value of 0.86 μM.

Polypyrrole-based bilayer nitrate amperometric biosensor with an integrated permselective poly-ortho-phenylenediamine layer for exclusion of inorganic interferences.

PubMed

Adeloju, Samuel B; Sohail, Manzar

2011-07-15

A bilayer amperometric nitrate biosensor with an integrated permselective layer has been developed for exclusion of inorganic anion and cation interferences. The inner PPy(polypyrrole)-NaR-NADH layer of the biosensor is formed by galvanostatic polymerization of pyrrole (Py) in presence of nitrate reductase (NaR) and nicotinamide adenine dinucleotide (NADH), followed by formation of the outer permselective poly-ortho-phenylenediamine (P-o-PDA) layer by potentiodynamic polymerization of ortho-phenylenediamine (o-PDA). The exclusion efficiency (E(eff)) of the outer layer in rejecting inorganic cation and anion interferences is evaluated by a new proposed relationship. 73-87% and 47-84% of anion and cation interferences, respectively, were efficiently rejected with the permselective layer. Further improvement in the exclusion efficiency for cations was accomplished by combining the use of the outer layer with the addition of 1mM EDTA into the measurement solution. The addition of EDTA improved the E(eff) achieved for cation rejection by 10-40% to give net E(eff) of 89-94%. The inclusion of the outer layer also aided the retention of NaR and NADH in the inner PPy-NaR-NADH layer and, hence, enabled improved amperometric detection of nitrate, achieving a detection limit of 0.20 μM and a linear concentration range of 10-500 μM with a 3.4%rsd (n=10). Copyright © 2011 Elsevier B.V. All rights reserved.

Degradation of toluene by ortho cleavage enzymes in Burkholderia fungorum FLU100

PubMed Central

Dobslaw, Daniel; Engesser, Karl-Heinrich

2015-01-01

Burkholderia fungorum FLU100 simultaneously oxidized any mixture of toluene, benzene and mono-halogen benzenes to (3-substituted) catechols with a selectivity of nearly 100%. Further metabolism occurred via enzymes of ortho cleavage pathways with complete mineralization. During the transformation of 3-methylcatechol, 4-carboxymethyl-2-methylbut-2-en-4-olide (2-methyl-2-enelactone, 2-ML) accumulated transiently, being further mineralized only after a lag phase of 2 h in case of cells pre-grown on benzene or mono-halogen benzenes. No lag phase, however, occurred after growth on toluene. Cultures inhibited by chloramphenicol after growth on benzene or mono-halogen benzenes were unable to metabolize 2-ML supplied externally, even after prolonged incubation. A control culture grown with toluene did not show any lag phase and used 2-ML as a substrate. This means that 2-ML is an intermediate of toluene degradation and converted by specific enzymes. The conversion of 4-methylcatechol as a very minor by-product of toluene degradation in strain FLU100 resulted in the accumulation of 4-carboxymethyl-4-methylbut-2-en-4-olide (4-methyl-2-enelactone, 4-ML) as a dead-end product, excluding its nature as a possible intermediate. Thus, 3-methylcyclohexa-3,5-diene-1,2-diol, 3-methylcatechol, 2-methyl muconate and 2-ML were identified as central intermediates of productive ortho cleavage pathways for toluene metabolism in B. fungorum FLU100. PMID:25130674

A new ab initio potential energy surface for the collisional excitation of HCN by para- and ortho-H{sub 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denis-Alpizar, Otoniel, E-mail: otonieldenisalpizar@gmail.com; Departamento de Física, Universidad de Matanzas, Matanzas 40100; Kalugina, Yulia

We present a new four-dimensional potential energy surface for the collisional excitation of HCN by H{sub 2}. Ab initio calculations of the HCN–H{sub 2} van der Waals complex, considering both molecules as rigid rotors, were carried out at the explicitly correlated coupled cluster with single, double, and perturbative triple excitations [CCSD(T)-F12a] level of theory using an augmented correlation-consistent triple zeta (aVTZ) basis set. The equilibrium structure is linear HCN–H{sub 2} with the nitrogen pointing towards H{sub 2} at an intermolecular separation of 7.20 a{sub 0}. The corresponding well depth is −195.20 cm{sup −1}. A secondary minimum of −183.59 cm{sup −1}more » was found for a T-shape configuration with the H of HCN pointing to the center of mass of H{sub 2}. We also determine the rovibrational energy levels of the HCN–para-H{sub 2} and HCN–ortho-H{sub 2} complexes. The calculated dissociation energies for the para and ortho complexes are 37.79 cm{sup −1} and 60.26 cm{sup −1}, respectively. The calculated ro-vibrational transitions in the HCN–H{sub 2} complex are found to agree by more than 0.5% with the available experimental data, confirming the accuracy of the potential energy surface.« less

H{sub 2} Ortho-to-para Conversion on Grains: A Route to Fast Deuterium Fractionation in Dense Cloud Cores?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bovino, S.; Grassi, T.; Schleicher, D. R. G.

Deuterium fractionation, i.e., the enhancement of deuterated species with respect to non-deuterated ones, is considered to be a reliable chemical clock of star-forming regions. This process is strongly affected by the ortho-to-para H{sub 2} ratio. In this Letter we explore the effect of the ortho–para (o–p) H{sub 2} conversion on grains on the deuteration timescale in fully-depleted dense cores, including the most relevant uncertainties that affect this complex process. We show that (i) the o–p H{sub 2} conversion on grains is not strongly influenced by the uncertainties on the conversion time and the sticking coefficient, and (ii) that the processmore » is controlled by the temperature and the residence time of ortho-H{sub 2} on the surface, i.e., by the binding energy. We find that for binding energies between 330 and 550 K, depending on the temperature, the o–p H{sub 2} conversion on grains can shorten the deuterium fractionation timescale by orders of magnitude, opening a new route for explaining the large observed deuteration fraction D {sub frac} in dense molecular cloud cores. Our results suggest that the star formation timescale, when estimated through the timescale to reach the observed deuteration fractions, might be shorter than previously proposed. However, more accurate measurements of the binding energy are needed in order to better assess the overall role of this process.« less

Regiospecific dechlorination of pentachlorophenol by dichlorophenol-adapted microorganisms in freshwater, anaerobic sediment slurries.

PubMed Central

Bryant, F O; Hale, D D; Rogers, J E

1991-01-01

The reductive dechlorination of pentachlorophenol (PCP) was investigated in anaerobic sediments that contained nonadapted or 2,4- or 3,4-dichlorophenol (DCP)-adapted microbial communities. Adaptation of sediment communities increased the rate of conversion of 2,4- or 3,4-DCP to monochlorophenols (CPs) and eliminated the lag phase before dechlorination was observed. Both 2,4- and 3,4-DCP-adapted sediment communities dechlorinated the six DCP isomers to CPs. The specificity of chlorine removal from the DCP isomers indicated a preference for ortho-chlorine removal by 2,4-DCP-adapted sediment communities and for para-chlorine removal by 3,4-DCP-adapted sediment communities. Sediment slurries containing nonadapted microbial communities either did not dechlorinate PCP or did so following a lag phase of at least 40 days. Sediment communities adapted to dechlorinate 2,4- or 3,4-DCP dechlorinated PCP without an initial lag phase. The 2,4-DCP-adapted communities initially removed the ortho-chlorine from PCP, whereas the 3,4-DCP-adapted communities initially removed the para-chlorine from PCP. A 1:1 mixture of the adapted sediment communities also dechlorinated PCP without a lag phase. Dechlorination by the mixture was regiospecific, following a para greater than ortho greater than meta order of chlorine removal. Intermediate products of degradation, 2,3,5,6-tetrachlorophenol, 2,3,5-trichlorophenol, 3,5-DCP, 3-CP, and phenol, were identified by a combination of cochromatography (high-pressure liquid chromatography) with standards and gas chromatography-mass spectrometry. PMID:1768102

Activation of Remote meta-C–H Bonds Assisted by an “End-on” Template

PubMed Central

Leow, Dasheng; Li, Gang; Mei, Tiansheng; Yu, Jin-Quan

2012-01-01

Controlling positional selectivity of C–H activation in molecules possessing multiple inequivalent C–H bonds is one of the most important challenges in developing synthetically useful C–H activation reactions. One widely used approach utilizes σ-chelating directing groups to achieve ortho-selectivity through conformational rigid five- or six-membered cyclic pre-transition states (TS).1–14 We envisioned that an “end-on” chelating template capable of delivering catalysts to previously inaccessible remote meta-C–H bonds via a macrocyclic cyclophane-like pre-TS could overcome the limitations imposed by traditional ortho-directing groups. Herein, we report a class of readily removable nitrile-containing templates that direct the activation of distal meta-C–H bonds (≥ 10 bonds away) of a tethered arene. We attribute this new mode of C–H activation to the weak “end-on” coordination of the linear nitrile group to metal center, as previously observed by Schwarz in the study of remote C–H activation of alkyl nitriles in gas phase.15, 16 The coordination geometry relieves the strain of the cyclophane-like pre-transition state of the meta-C–H activation event. Remarkably, this template overrides electronic and steric biases and ortho-directing effects with two broadly useful classes of arene substrates (toluene derivatives and hydrocinnamic acids), thus constituting a fundamentally new mode of directed C–H activation that is anticipated to be widely adopted. PMID:22739317

Study of the chemistry of ortho- and para-biphenylnitrenes by laser flash photolysis and time-resolved IR experiments and by B3LYP and CASPT2 calculations.

PubMed

Tsao, Meng-Lin; Gritsan, Nina; James, Tammi R; Platz, Matthew S; Hrovat, David A; Borden, Weston Thatcher

2003-08-06

The photochemistry of ortho-biphenyl azide (1a) has been studied by laser flash photolysis (LFP), with UV-vis and IR detection of the transient intermediates formed. LFP (266 nm) of 1a in glassy 3-methylpentane at 77 K releases singlet ortho-biphenylnitrene (1b) (lambda(max) = 410 nm, tau = 59 +/- 6 ns), which under these conditions decays cleanly to the lower energy triplet state. In fluid solution at 298 K, 1b rapidly (tau < 10 ns) partitions between formation of isocarbazole (4) (lambda(max) = 430 nm, tau = 70 ns) and benzazirine (1e) (lambda(max) = 305 nm, tau = 12 ns). Isocarbazole 4 undergoes a 1,5-hydrogen shift, with k(H)/k(D) = 3.4 at 298 K to form carbazole 9 and smaller amounts of two other isocarbazoles (7 and 8). Benzazirine 1e ring-opens reversibly to azacycloheptatetraene (1f), which serves as a reservoir for singlet nitrene 1b. Azacycloheptatetraene 1f ultimately forms carbazole 9 on the millisecond time scale by the pathway 1f --> 1e --> 1b --> 4 --> 9. The energies of the transient intermediates and of the transition structures connecting them were successfully predicted by CASPT2/6-31G calculations. The electronic and vibrational spectra of the intermediates, computed by density functional theory, support the assignment of the transient spectra, observed in the formation of 9 from 1a.

Rotational excitation of HCN by para- and ortho-H₂.

PubMed

Vera, Mario Hernández; Kalugina, Yulia; Denis-Alpizar, Otoniel; Stoecklin, Thierry; Lique, François

2014-06-14

Rotational excitation of the hydrogen cyanide (HCN) molecule by collisions with para-H2(j = 0, 2) and ortho-H2(j = 1) is investigated at low temperatures using a quantum time independent approach. Both molecules are treated as rigid rotors. The scattering calculations are based on a highly correlated ab initio 4-dimensional (4D) potential energy surface recently published. Rotationally inelastic cross sections among the 13 first rotational levels of HCN were obtained using a pure quantum close coupling approach for total energies up to 1200 cm(-1). The corresponding thermal rate coefficients were computed for temperatures ranging from 5 to 100 K. The HCN rate coefficients are strongly dependent on the rotational level of the H2 molecule. In particular, the rate coefficients for collisions with para-H2(j = 0) are significantly lower than those for collisions with ortho-H2(j = 1) and para-H2(j = 2). Propensity rules in favor of even Δj transitions were found for HCN in collisions with para-H2(j = 0) whereas propensity rules in favor of odd Δj transitions were found for HCN in collisions with H2(j ⩾ 1). The new rate coefficients were compared with previously published HCN-para-H2(j = 0) rate coefficients. Significant differences were found due the inclusion of the H2 rotational structure in the scattering calculations. These new rate coefficients will be crucial to improve the estimation of the HCN abundance in the interstellar medium.

A feasibility study of ortho-positronium decays measurement with the J-PET scanner based on plastic scintillators

NASA Astrophysics Data System (ADS)

Kamińska, D.; Gajos, A.; Czerwiński, E.; Alfs, D.; Bednarski, T.; Białas, P.; Curceanu, C.; Dulski, K.; Głowacz, B.; Gupta-Sharma, N.; Gorgol, M.; Hiesmayr, B. C.; Jasińska, B.; Korcyl, G.; Kowalski, P.; Krzemień, W.; Krawczyk, N.; Kubicz, E.; Mohammed, M.; Niedźwiecki, Sz.; Pawlik-Niedźwiecka, M.; Raczyński, L.; Rudy, Z.; Silarski, M.; Wieczorek, A.; Wiślicki, W.; Zgardzińska, B.; Zieliński, M.; Moskal, P.

2016-08-01

We present a study of the application of the Jagiellonian positron emission tomograph (J-PET) for the registration of gamma quanta from decays of ortho-positronium (o-Ps). The J-PET is the first positron emission tomography scanner based on organic scintillators in contrast to all current PET scanners based on inorganic crystals. Monte Carlo simulations show that the J-PET as an axially symmetric and high acceptance scanner can be used as a multi-purpose detector well suited to pursue research including e.g. tests of discrete symmetries in decays of ortho-positronium in addition to the medical imaging. The gamma quanta originating from o-Ps decay interact in the plastic scintillators predominantly via the Compton effect, making the direct measurement of their energy impossible. Nevertheless, it is shown in this paper that the J-PET scanner will enable studies of the { o-Ps }→ 3γ decays with angular and energy resolution equal to σ (θ ) ≈ {0.4°} and σ (E) ≈ 4.1 {keV}, respectively. An order of magnitude shorter decay time of signals from plastic scintillators with respect to the inorganic crystals results not only in better timing properties crucial for the reduction of physical and instrumental background, but also suppresses significantly the pile-ups, thus enabling compensation of the lower efficiency of the plastic scintillators by performing measurements with higher positron source activities.

Degradation of phenanthrene by Burkholderia sp. C3: initial 1,2- and 3,4-dioxygenation and meta- and ortho-cleavage of naphthalene-1,2-diol.

PubMed

Seo, Jong-Su; Keum, Young-Soo; Hu, Yuting; Lee, Sung-Eun; Li, Qing X

2007-02-01

Burkholderia sp. C3 was isolated from a polycyclic aromatic hydrocarbon (PAH)-contaminated site in Hilo, Hawaii, USA, and studied for its degradation of phenanthrene as a sole carbon source. The initial 3,4-C dioxygenation was faster than 1,2-C dioxygenation in the first 3-day culture. However, 1-hydroxy-2-naphthoic acid derived from 3,4-C dioxygenation degraded much slower than 2-hydroxy-1-naphthoic acid derived from 1,2-C dioxygenation. Slow degradation of 1-hydroxy-2-naphthoic acid relative to 2-hydroxy-1-naphthoic acid may trigger 1,2-C dioxygenation faster after 3 days of culture. High concentrations of 5,6- and 7,8-benzocoumarins indicated that meta-cleavage was the major degradation mechanism of phenanthrene-1,2- and -3,4-diols. Separate cultures with 2-hydroxy-1-naphthoic acid and 1-hydroxy-2-naphthoic acid showed that the degradation rate of the former to naphthalene-1,2-diol was much faster than that of the latter. The two upper metabolic pathways of phenanthrene are converged into naphthalene-1,2-diol that is further metabolized to 2-carboxycinnamic acid and 2-hydroxybenzalpyruvic acid by ortho- and meta-cleavages, respectively. Transformation of naphthalene-1,2-diol to 2-carboxycinnamic acid by this strain represents the first observation of ortho-cleavage of two rings-PAH-diols by a Gram-negative species.

The Age of OrthoInfo: A Randomized Controlled Trial Evaluating Patient Comprehension of Informed Consent.

PubMed

Egekeze, Nkemakolam; Dubin, Jonathan; Williams, Karen; Bernhardt, Mark

2016-10-05

Integral to an orthopaedic surgeon-patient informed consent discussion is the assessment of patient comprehension of their medical care. However, little is known about how to optimize patient comprehension of an informed consent discussion. The purpose of our study was to evaluate three time-controlled informed consent discussion methods to determine which optimized patient comprehension immediately after the discussion. Sixty-seven consecutive patients with knee osteoarthritis who were considered medically appropriate for a knee corticosteroid injection were enrolled in our trial. Participants were randomized and were allocated into one of three groups in a parallel fashion and 1:1:1 ratio. Our three groups varied by sensory input and included verbal (hearing), verbal and video (hearing and sight), and verbal and model (hearing, sight, and touch). Each participant listened to a 10-minute scripted lecture given by a researcher; this lecture was based on content from the American Academy of Orthopaedic Surgeons patient education web site OrthoInfo. Patient comprehension was assessed after the lecture using a validated questionnaire called the Nkem test. Our primary outcome evaluated patient comprehension utilizing a pairwise comparison of mean comprehension scores between the groups. The primary outcome was analyzed using a one-way analysis of variance with the least significant difference calculated post hoc and a 95% confidence interval (95% CI). The health-care staff, study participants, and outcome assessor were each blinded to group assignments. The mean comprehension scores were 84% (95% CI, 79% to 88%) for the verbal and model group, 74% (95% CI, 63% to 80%) for the verbal and video group, and 71% (95% CI, 61% to 80%) for the verbal group. The omnibus analysis of variance was significant and showed a difference among the groups (p = 0.019). The pairwise comparison of the groups using the least significant difference calculated post hoc showed that the verbal and model group outperformed the verbal group (p = 0.01) and the verbal and video group (p = 0.023). Multisensory patient education incorporating OrthoInfo and an anatomic model optimized patient comprehension immediately after a time-controlled informed consent discussion. This finding could play an important role in improving surgeon-patient communication in the field of orthopaedic surgery. Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.

Structural Modifications of Benzimidazoles via Multi-Step Synthesis and Their Impact on Sirtuin-Inhibitory Activity.

PubMed

Yoon, Yeong Keng; Choon, Tan Soo

2016-01-01

Benzimidazole derivatives have been shown to possess sirtuin-inhibitory activity. In the continuous search for potent sirtuin inhibitors, systematic changes on the terminal benzene ring were performed on previously identified benzimidazole-based sirtuin inhibitors, to further investigate their structure-activity relationships. It was demonstrated that the sirtuin activities of these novel compounds followed the trend where meta-substituted compounds possessed markedly weaker potency than ortho- and para-substituted compounds, with the exception of halogenated substituents. Molecular docking studies were carried out to rationalize these observations. Apart from this, the methods used to synthesize the interesting compounds are also discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

BCl3 -Induced Annulative Oxo- and Thioboration for the Formation of C3-Borylated Benzofurans and Benzothiophenes.

PubMed

Warner, Andrew J; Churn, Anna; McGough, John S; Ingleson, Michael J

2017-01-02

BCl 3 -induced borylative cyclization of aryl-alkynes possessing ortho-EMe (E=S, O) groups represents a simple, metal-free method for the formation of C3-borylated benzothiophenes and benzofurans. The dichloro(heteroaryl)borane primary products can be protected to form synthetically ubiquitous pinacol boronate esters or used in situ in Suzuki-Miyaura cross couplings to generate 2,3-disubstituted heteroarenes from simple alkyne precursors in one pot. In a number of cases alkyne trans-haloboration occurs alongside, or instead of, borylative cyclization and the factors controlling the reaction outcome are determined. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization and Validation of a Sensitive Method for HPLC-PDA Simultaneous Determination of Torasemide and Spironolactone in Human Plasma using Central Composite Design.

PubMed

Subramanian, Venkatesan; Nagappan, Kannappan; Sandeep Mannemala, Sai

2015-01-01

A sensitive, accurate, precise and rapid HPLC-PDA method was developed and validated for the simultaneous determination of torasemide and spironolactone in human plasma using Design of experiments. Central composite design was used to optimize the method using content of acetonitrile, concentration of buffer and pH of mobile phase as independent variables, while the retention factor of spironolactone, resolution between torasemide and phenobarbitone; and retention time of phenobarbitone were chosen as dependent variables. The chromatographic separation was achieved on Phenomenex C(18) column and the mobile phase comprising 20 mM potassium dihydrogen ortho phosphate buffer (pH-3.2) and acetonitrile in 82.5:17.5 v/v pumped at a flow rate of 1.0 mL min(-1). The method was validated according to USFDA guidelines in terms of selectivity, linearity, accuracy, precision, recovery and stability. The limit of quantitation values were 80 and 50 ng mL(-1) for torasemide and spironolactone respectively. Furthermore, the sensitivity and simplicity of the method suggests the validity of method for routine clinical studies.

Role of Mediator and Effects of Temperature on ortho-C-N Bond Fusion Reactions of Aniline Using Ruthenium Templates: Isolation and Characterization of New Ruthenium Complexes of the in-Situ-Generated Ligands.

PubMed

Roy, Suman K; Sengupta, Debabrata; Rath, Santi Prasad; Saha, Tanushri; Samanta, Subhas; Goswami, Sreebrata

2017-05-01

In this work, ortho-C-N bond fusion reactions of aniline are followed by the use of two different ruthenium mediators. Reaction of aniline with [Ru III (terpy)Cl 3 ] (terpy = 2,2':6',2″-terpyridine) resulted in a trans bis-aniline ruthenium(II) complex [1] + which upon oxidation with H 2 O 2 produced compound [2] + of a bidentate ligand, N-phenyl-1,2-benzoquinonediimine, due to an oxidative ortho-C-N bond fusion reaction. Complex [1] + and aniline (neat) at 185 °C produced a bis-chelated ruthenium complex (3). A previously reported complex [Ru II (N-phenyl-1,2-benzoquinonediimine)(aniline) 2 (Cl) 2 ] (5) undergoes similar oxidation by air at 185 °C to produce complex [3]. A separate chemical reaction between aniline and strongly oxidizing tetra-n-propylammonium perruthenate [(n-pr) 4 N] + [RuO 4 ] - in air produced a ruthenium complex [4] of a N 4 -tetraamidophenylmacrocycle ligand via multiple ortho-C-N bond fusion reaction. Notably, the yield of this product is low (5%) at 100 °C but increases to 25% in refluxing aniline. All these complexes are characterized fully by their physicochemical characterizations and X-ray structure determination. From their structural parameters and other spectroscopic studies, complex [2] + is assigned as [Ru II (terpy)(N-phenyl-1,2-benzoquinonediimine)(Cl)] + whereas complex [4] is described as a ruthenium(VI) complex comprised of a reduced deprotonated N-phenyl-1,2-diamidobenzene and N 4 -tetraamidophenylmacrocyclic ligand. Complex [2] + exhibits one reversible oxidation at 1.32 V and one reversible reduction at -0.75 V vs Ag/AgCl reference electrode. EPR of the electrogenerated complexes has revealed that the oxidized complex is a ruthenium(III) complex with an axial EPR spectrum at g av = 2.06. The reduced complex [2], on the other hand, shows a single-line EPR signal at g av = 1.998. In contrast, complex [4] shows two successive one-electron oxidation waves at 0.5 and 0.8 V and an irreversible reduction wave at -0.9 V. EPR studies of the oxidized complexes [4] + and [4] 2+ reveal that oxidations are ligand centered. DFT calculations were employed to elucidate the electronic structures as well as the redox processes associated with the above complexes. Aerial ortho-C-N bond fusion reactions of aniline using two different mediators, viz. [Ru III (terpy)Cl 3 ] and [(n-pr) 4 N] + [RuO 4 ] - , have been followed. It is found that in the case of oxidizable Ru(III) mediator complex, C-N bond fusion is limited only to dimerization reaction whereas the high-valent Ru(VII) salt mediates multiple C-N bond fusion reactions leading to the formation of a novel tetradentate N 4 -tetraamidophenylmacrocyclic ligand. Valence ambiguity in the complexes of the resultant redox-active ligands is scrutinized.

The changing of coastal landform at Chikou barrier island and lagoon coast, Tainan, Southwestern Taiwan

NASA Astrophysics Data System (ADS)

Jen, C.-H.; Chyi, S.-J.; Hsiao, L.-L.; Wu, M.-S.; Lei, H.-F.

2012-04-01

The coast of southwestern Taiwan is mainly made of barriers and lagoons, which are prone to erosional and depositional processes. By using a serial maps, historical survey data, and RTK-GPS survey data, the changes of coast landforms are depicted. The maps being used in this study include (1) 1904 map(1:50000 scale), (2) 1920 map (1:50000 scale), (3) 1921 map (1:25000 scale), (4) 1924 map (1:25000 scale), (5) 1956 map (1:25000 scale), (6) 1975 map with ortho-rectified image (1:5000 scale), (7) 1983 map with ortho-rectified image (1:5000 scale), (8) 1989 map with ortho-rectified image (1:5000 scale), (9) 1992 map with ortho-rectified image (1:5000 scale), (10) 2001 map with ortho-rectified image (1:5000 scale). All maps are scanned and georeferenced to build a GIS archive for digitizing and further analysis. The results show that this coast was made of continuous sand barriers and lagoons. While lagoons were gradually shrinking, the sand barriers had remained stable from 1904 to 1924. After that, lagoons substantially deposited in the southern part and sand barriers became landward. In 1975 map, lagoons vanished and replaced with a tidal flat and tidal creeks. The following maps show that lagoons start to form again and sand barriers moving landward continuously. It is a significant sign of serious erosion in the coast. The RTK-GPS survey data in recent years show more detail of coast erosion and landform changes. The post-typhoon investigation results show that the seaward side of barrier island is eroded largely, especially for the two segments of the central part of the barrier island. Some depositions were found on the top of northern and central part of barrier dune, as well as washovers. In the southern barrier island, the depositions were carried to backshore and were obstructed in front of the bamboo piles and marine solid bags. The survey indicated the areas eroded by storm surge were gradually accumulating except for the beaches separate with plastic sheet piles and marine solid bags, especially the northern section-north, after the Typhoon Megi happened two month. In late February of 2011, there are some deposition on the top of primary dune, backdune and tidal flat. But the parts of seaward beach which wave can reach are continuously eroded, especially the central segment of the barrier island is mostly vulnerable. In particular, the latter part of southern beach was accumulated, concerning with alongshore current transport. In the late winter monsoon season, elevation changes are smaller than in the medium, corresponding with the wave condition. The latter part of south section begin to be eroded, the sediments may be taken away by the southward current. Area A, located the central of barrier island, attacked by wave continuously, elevation of dune decrease constantly, and then overwashed frequently. Keywords: sand barrier and lagoon coast, archive map analysis, RTK-GPS survey, overwash

[The long-term clinical effects of orthokeratology in high myopia children].

PubMed

Zhou, Jianlan; Xie, Peiying; Wang, Dan; Guo, Xi; Yang, Lina

2015-07-01

To investigate the long-term clinical effects of orthokeratology (ortho-k) in high myopia children with 5 years of follow-ups. Prospective study. We chose 30 high myopia patients to wear ortho-k contact lenses (CLs) for controlling or delaying myopia progression from 2003. Among them, there were 10 boys and 20 girls whose average age was (15 ± 2) years, spherical diopters were (-7.34 ± 0.91) D, corneal astigmatism diopters were (-1.06 ± 0.62) D, uncorrected visual acuity was LogMAR 0.89 ± 0.29, corneal flattened curvature was (43.54 ± 1.16) D, and axial length was (26.38 ± 0.94) mm. All patients, with informed consent before fitting of ortho-k CLs, had conventional refraction and ocular tests. We compared the values of spherical diopters, visual acuity, corneal flattened curvature and axial length before and 6 months, 1 year, 2 years, 3 years, 4 years and 5 years after wearing CLs, respectively. The results were analyzed by SPSS 16.0 software. During the five years of observation periods, all patients' visual acuity and corneal flattened curvature were different from the pre-fitting (P < 0.05). Compared to the pre-fitting, the naked visual acuity was some degree improved, it was LogMAR 0.45 ± 0.31, 0.49 ± 0.32, 0.43 ± 0.30, 0.47 ± 0.31, 0.58 ± 0.35, 0.53 ± 0.27, respectively. F = 10.725, P = 0.000. Corneal flatten curvature was tend to be flatter, such was 41.14 ± 1.54, 41.75 ± 1.88, 41.54 ± 2.10, 41.73 ± 1.89, 41.94 ± 1.61, 40.70 ± 1.67. F = 10.161, P = 0.000 (All P < 0.05). The spherical diopters during the first two years after wearing ortho-k CLs were significantly reduced, compared with the previous values (it was -5.23 ± 1.81, -5.59 ± 2.75, -6.29 ± 2.12, -6.63 ± 2.31, -6.83 ± 2.33, -7.01 ± 1.81, respectively, F = 4.929, P = 0.000), and kept stable in the long-term observation. The axial length checked at 5 years was slightly elongated (it was 26.41 ± 0.90, 26.68 ± 0.93, 26.69 ± 1.06, 26.75 ± 0.94, 26.81 ± 1.04, 27.04 ± 1.01. F = 1.831, P = 0.094). The axial elongation was retarded by using ortho-k CLs in high myopia children. All patients were not subjected to severe complications which may lead to quitting the enrollments. Orthokeratology used in controlling or delaying high myopia progression is definitely outstanding in 5 years observations. Standard lens wearing and regular lens check improve safety of lens use in high myopia.

A modified artificial immune system based pattern recognition approach -- an application to clinic diagnostics

PubMed Central

Zhao, Weixiang; Davis, Cristina E.

2011-01-01

Objective This paper introduces a modified artificial immune system (AIS)-based pattern recognition method to enhance the recognition ability of the existing conventional AIS-based classification approach and demonstrates the superiority of the proposed new AIS-based method via two case studies of breast cancer diagnosis. Methods and materials Conventionally, the AIS approach is often coupled with the k nearest neighbor (k-NN) algorithm to form a classification method called AIS-kNN. In this paper we discuss the basic principle and possible problems of this conventional approach, and propose a new approach where AIS is integrated with the radial basis function – partial least square regression (AIS-RBFPLS). Additionally, both the two AIS-based approaches are compared with two classical and powerful machine learning methods, back-propagation neural network (BPNN) and orthogonal radial basis function network (Ortho-RBF network). Results The diagnosis results show that: (1) both the AIS-kNN and the AIS-RBFPLS proved to be a good machine leaning method for clinical diagnosis, but the proposed AIS-RBFPLS generated an even lower misclassification ratio, especially in the cases where the conventional AIS-kNN approach generated poor classification results because of possible improper AIS parameters. For example, based upon the AIS memory cells of “replacement threshold = 0.3”, the average misclassification ratios of two approaches for study 1 are 3.36% (AIS-RBFPLS) and 9.07% (AIS-kNN), and the misclassification ratios for study 2 are 19.18% (AIS-RBFPLS) and 28.36% (AIS-kNN); (2) the proposed AIS-RBFPLS presented its robustness in terms of the AIS-created memory cells, showing a smaller standard deviation of the results from the multiple trials than AIS-kNN. For example, using the result from the first set of AIS memory cells as an example, the standard deviations of the misclassification ratios for study 1 are 0.45% (AIS-RBFPLS) and 8.71% (AIS-kNN) and those for study 2 are 0.49% (AIS-RBFPLS) and 6.61% (AIS-kNN); and (3) the proposed AIS-RBFPLS classification approaches also yielded better diagnosis results than two classical neural network approaches of BPNN and Ortho-RBF network. Conclusion In summary, this paper proposed a new machine learning method for complex systems by integrating the AIS system with RBFPLS. This new method demonstrates its satisfactory effect on classification accuracy for clinical diagnosis, and also indicates its wide potential applications to other diagnosis and detection problems. PMID:21515033