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1

Organofunctional Phosphazenes and Organofunctional Phosphazene Polymers.  

National Technical Information Service (NTIS)

Recent work has shown that the range of synthesis of new and useful phosphazene derivatives can be dramatically expanded by incorporation of an organo-functional substituent on the phasphazene ring. This substituent can serve as the site for various synth...

C. W. Allen

1983-01-01

2

Phosphazene Diamines.  

National Technical Information Service (NTIS)

The synthesis of a specific phosphazene diamine was optimized, other phosphorus-containing diamines were prepared, and their effect upon certain characteristics of epoxy resins, prepared via reaction with MY 720, in particular, char yield at elevated temp...

D. H. Harris K. L. Paciorek R. H. Kratzer T. I. Ito

1980-01-01

3

Phosphazenes (2010)  

SciTech Connect

A review of the literature published in 2009 shows an increase in the number of publications addressing phosphazene chemistry over 2008, which suggests a continued strong interest in these intriguing materials. Prominently is the emphasis in the bioactive and biocompatible nature of these materials; although many other applications also exist. Phosphazenes are formed from a phosphorus and nitrogen backbone with pendant group attachments at phosphorus. Typically, they are drawn with alternating single and double bonds between the alternating phosphorus and nitrogen atoms. However, unlike the familiar poly(acetylenes) or poly(thiophenes), the phosphazene backbone is not electrically conductive as there are orbital nodes at phosphorus. Thus, electron delocalization occurs between phosphorus atoms, but not through them. The result of this bonding is a highly flexible backbone that can be controlled through adoit pendant group attachment revealing numerous materials and structures. In this review, novel aspects of the chemistry, structure, and applications of phosphazenes will be discussed.

Frederick F. Stewart

2010-12-01

4

Gas permeability and ideal selectivity of poly[bis-(phenoxy)phosphazene], poly[bis-(4- tert-butylphenoxy)phosphazene], and poly[bis-(3,5-di- tert-butylphenoxy) 1.2(chloro) 0.8phosphazene  

Microsoft Academic Search

Described in this paper is the synthesis and gas permeability characterization of poly[bis-(4-tert-butylphenoxy)phosphazene], and poly[bis-(3,5-di-tert-butylphenoxy)1.2(chloro)0.8phosphazene]. In general, linear chloro-containing polyphosphazenes are hydrolytically unstable. However, in this work, a novel polymer, poly[bis-(3,5-di-tert-butylphenoxy)1.2(chloro)0.8phosphazene], was observed to have an unusually high degree of hydrolytic stability and excellent membrane formation characteristics. Data derived from these polymers were compared to that of the more common

Christopher J. Orme; John R. Klaehn; Frederick F. Stewart

2004-01-01

5

Organosilylphosphazene Oligomers and Polymers: Synthesis via (Lithioaryloxy)phosphazenes.  

National Technical Information Service (NTIS)

(Lithioaryloxy)phosphazenes have been used as reaction intermediates for the synthesis of phosphazenes that bear organosilicon side groups. The synthetic pathways were developed at two levels, first with the use of small-molecule cyclic phosphazenes as re...

H. R. Allcock W. D. Coggio R. S. Archibald D. J. Brennan

1989-01-01

6

Transsilylation Reactions of Phosphazene Precursors,  

National Technical Information Service (NTIS)

Me3SiN-P(OCH2CF3)Me2 (1) are useful precursors to poly-(alkyl/arylphosphazenes) via a thermally induced condensation polymerization process. Aside from this important thermolysis reaction, however, the chemistry of these phosphazene precursors has not bee...

U. G. Wettermark R. H. Neilson

1987-01-01

7

Phosphazene polymer containing composites and method for making phosphazene polymer containing composites  

DOEpatents

The object of the invention is to provide a composite material comprised of phosphazene polymer. A feature of phosphazene-containing composites is their superior stiffness, thermal stability, and hardness which is lacking in more typical composite constituents. An advantage of using phosphazene composites is a wider range of applications, including uses in harsh environments. Another object of the present invention provides a method for producing phosphazene-containing composite materials through a pultrusion process. In brief, these and other objects are achieved by a composite produced by first coating a reinforcing material with an inorganic phosphazene compound and then polymerizing the phosphazene compound so as to confer superior thermal, physical and chemical resistance qualities to the composite. 2 figs., 6 tabs.

Allen, C.A.; Grey, A.E.; McCaffrey, R.R.; Simpson, B.M.; Stone, M.L.

1990-12-31

8

Ring-Opening Polymerization of Phosphazenes.  

National Technical Information Service (NTIS)

Phosphazenes comprise a broad range of cyclic or linear small-molecules and high polymers that occupy and important place in the chemistry of heterocyclic compounds and new macromolecules. Typical structures are shown in Table 7.1. In these molecules the ...

H. R. Allcock

1993-01-01

9

Surface functionalization with phosphazene substrates, Part IV: Silica and Si(100) surface functionalization using cyclophosphazenes partially substituted with trialkoxysilane derivatives and PEG750 monomethylether, 2,2,3,3-tetrafluoropropanol and 4-hydroxyazobenzene  

Microsoft Academic Search

This paper deals with the possibility of functionalizing the surface of silicon-based materials by exploiting cyclophosphazenes containing suitable substituent groups. Thus, phosphazene trimers were prepared, containing about 50% of the reactive sites substituted by ?-aminopropyltriethoxy silane (APTES), while the residual positions in the cycle contain poly(ethylene glycol) monomethylether (MW approx. 750; PEG-750-ME), tetrafluoropropanol (TFP) and 4-hydroxyazobenzene (AzB). Using these novel

Roberto Milani; Alessandro Sassi; Alfonso Venzo; Roberta Bertani; Luca Fambri; Mario Gleria

2007-01-01

10

Sorption and diffusion of organic vapors in poly[bis(trifluoroethoxy) phosphazene] and poly[bis(phenoxy)phosphazene] membranes  

Microsoft Academic Search

The sorption isotherms and diffusivities for vapors of some selected simple alcohols (methanol, ethanol, isopropanol, and 2-butanol), ketones (acetone, methyl ethyl ketone, and methyl isobutyl ketone), and aromatic compounds (benzene, toluene, and xylene) in poly[bis(trifluoroethoxy)phosphazene] (PTFEP) and poly[bis(phenoxy)phosphazene] (PPOP) were determined by integral sorption-desorption experiments at 35°C. The sorption isotherms for these compounds evaluated were almost linear to obey Henry's

Sun Yi-Ming; Lin Cheng-Li; Chen Yuan-Kai; Wu Chi-Huang

1997-01-01

11

Novel fire-resistant polyphosphazenes and phosphazene-containing polymers  

Microsoft Academic Search

A functionalized polyphosphazene, poly[bis(carboxylatophenoxy)phosphazene], was blended with a structural polyurethane via reactive mixing of the polymer with diisocyanate and diol prepolymers. The thermal stabilities of the resultant foams were analyzed by thermogravimetric analysis (TGA). Both qualitative and quantitative flame tests indicated an increase in flame resistance at loadings of 20 wt% and above. Methods for the incorporation of phosphate and

Jonathan Paul Taylor

2000-01-01

12

Helical chirality transmission through a p-phenylene fragment in a hexa-lambda5-phosphazene.  

PubMed

The helical chirality of a conformationally stable macrobicyclic tri-lambda5-phosphazene is propagated through to its C3 symmetry axis and causes a measurable stereoinduction in the formation process of a second macrobicyclic tri-lambda5-phosphazene unit connected to the former one by a p-phenylene linker. PMID:17918955

Alajarín, Mateo; López-Leonardo, Carmen; Berná, José

2007-10-06

13

Insertion of benzynes into the P?N Bond of P-alkenyl(alkynyl)-?5-phosphazenes.  

PubMed

Benzynes, generated from 2-(trimethylsilyl)phenyl triflates, have been found to react with P-Alkenyl-?(5)-phosphazenes via a formal ?-insertion into the P?N bond. A subsequent retro [2 + 2] cycloaddition/6? electrocyclization/protonation cascade explains the formation of the resulting 1,4-benzazaphosphorinium triflates. P-Alkynyl ?(5)-phosphazenes and phosphane sulfides undergo similar transformations. PMID:21954976

Alajarin, Mateo; Lopez-Leonardo, Carmen; Raja, Rosalia; Orenes, Raul-Angel

2011-09-28

14

A novel, two step method for the modification of silicon surfaces with organic groups by chlorinated phosphazene plasma deposition and subsequent reaction in solution  

Microsoft Academic Search

In this work the surface of silicon substrates has been modified with organic ligands by exploiting chlorinated phosphazene as coupling agent. Hexachlorocyclophosphazene-derived thin films were deposited by Glow-Discharge-induced Sublimation (GDS) and then treated with an anhydrous tetrahydrofuran solution of trifluoroethanol and 4-cyanophenol as organic nucleophilic reagents. The sublimation of the chlorinated molecules and their interaction with the plasma ions and

A. Sassi; G. Maggioni; R. Milani; S. Carturan; M. Gleria; G. Della Mea

2007-01-01

15

Phosphorus-nitrogen compounds: Part 28. Syntheses, structural characterizations, antimicrobial and cytotoxic activities, and DNA interactions of new phosphazenes bearing vanillinato and pendant ferrocenyl groups  

NASA Astrophysics Data System (ADS)

The gradually Cl replacement reactions of spirocyclic mono (1 and 2) and bisferrocenyl cyclotriphosphazenes (3-5) with the potassium salt of 4-hydroxy-3-methoxybenzaldehyde (potassium vanillinate) gave mono (1a-5a), geminal (gem-1b-5b), non-geminal (cis-1b, cis-5b and trans-2b-5b), tri (1c-5c) and tetra-substituted phosphazenes (1d-5d). Some phosphazenes have stereogenic P-center(s). The chirality of 4c was verified using chiral HPLC column. Electrochemical behaviors were influenced only by the number of ferrocene groups, but not the length of the amine chains and the substituent(s). The structures of the new phosphazenes were determined by FTIR, MS, 1H, 13C and 31P NMR, HSQC and HMBC spectral data. The solid-state structures of cis-1b and 4d were examined by single crystal X-ray diffraction techniques. The twelve phosphazene derivatives were screened for antimicrobial activity and the compounds 5a, cis-1b and 2c exhibited the highest antibacterial activity against G(+) and G(-) bacteria. In addition, it was found that overall gem-1b inhibited the growth of Mycobacterium tuberculosis. The compounds 1d, 2d and 4d were tested in HeLa cancer cell lines. Among these compounds, 2d had cytotoxic effect on HeLa cell in the first 48 h. Moreover, interactions between compounds 2a, gem-1b, gem-2b, cis-1b, 2c, 3c, 4c, 5c, 1d, 2d and 4d, and pBR322 plasmid DNA were investigated.

Tümer, Yasemin; Asmafiliz, Nuran; K?l?ç, Zeynel; Hökelek, Tuncer; Yasemin Koç, L.; Aç?k, Leyla; Yola, Mehmet Lütfi; Solak, Ali Osman; Öner, Ya?mur; Dündar, Devrim; Yavuz, Makbule

2013-10-01

16

High pressure Raman microprobe studies of phosphazene trimers  

SciTech Connect

A representative class of molecules in which chemical bonding is controlled by marked differences in atom electronegativity as well as d-orbital involvement is exemplified by the planar cyclic phosphazene system, (NPX/sub 2/)/sub 3/, where X represents substituent groups bonded to the ring phosphorus atoms. Ab initio molecular orbital calculations of both chloro- and fluorotrimers using an extended basis set also indicate the presence of highly localized bonding. In these molecules, the sigma electron density on nitrogen is directed inside the ring with the non-bonding pi-orbital normal to the ring. Vibrational Raman spectra of chloro- and fluorophosphazene trimers as a function of applied pressure have been measured in this work and are used to confirm the mode assignments and evaluate subtle changes in chemical bonding induced by the applied pressure.

Exarhos, G.J.; Hess, N.J.

1988-04-01

17

Auger parameter measurements of phosphorus compounds for characterization of phosphazenes  

SciTech Connect

This paper presents x-ray generated photoelectron and Auger transition data for several phosphorus reference compounds, including PCl/sub 3/, P/sub 3/N/sub 5/, P/sub 2/O/sub 5/, (C/sub 6/H/sub 5/)/sub 3/P(C/sub 5/H/sub 4/), (C/sub 6/H/sub 5/)/sub 4/PBr, KH/sub 2/PO/sub 4/ (KDP), NH/sub 4/H/sub 2/PO/sub 4/ (ADP), and NH/sub 4/PF/sub 6/. This data has been used to determine the relative ionicity and polarizability of phosphorus in the chlorophosphazene trimer ((NPCl/sub 2/)/sub 3/) and polymer ((NPCl/sub 2/)/sub n/). The results support recent molecular orbital calculations that predict a highly polarized backbone bond in the phosphazenes. Furthermore, the chlorophosphazene polymer was observed to have a greater value for the Auger parameter than the chlorotrimer, indicating that the media surrounding the polymer is more polarizable than that surrounding the trimer. 15 refs., 2 figs., 2 tabs.

Dake, L.S.; Baer, D.R.; Friedrich, D.M.

1988-10-01

18

Auger parameter measurements of phosphorus compounds for characterization of phosphazenes  

SciTech Connect

X-ray generated photoelectron and Auger transition data for several phosphorus reference compounds, including PCl/sub 3/, P/sub 3/ N/sub 5/, P/sub 2/ O/sub 5/, (C/sub 6/ H/sub 5/ )/sub 3/ P(C/sub 5/ H/sub 4/ ), (C/sub 6/ H/sub 5/ )/sub 4/ PBr, KH/sub 2/ PO/sub 4/ , NH/sub 4/H/sub 2/PO/sub 4/, and NH/sub 4/ PF/sub 6/ are presented. These data have been used to determine the relative ionicity and polarizability of phosphorus in the chlorophosphazene trimer ((NPCl/sub 2/ )/sub 3/ ) and polymer ((NPCl/sub 2/ )/sub n/ ). The results support recent molecular-orbital calculations that predict a highly polarized backbone bond in the phosphazenes. Furthermore, the chlorophosphazene polymer was observed to have a greater value for the Auger parameter than the chlorotrimer, indicating that the bonding environment surrounding the polymer is more polarizable than that surrounding the trimer.

Dake, L.S.; Baer, D.R.; Friedrich, D.M.

1989-05-01

19

Organocatalytic Stereoselective Ring-Opening Polymerization of Lactide with Dimeric Phosphazene Bases  

SciTech Connect

Highly isotactic polylactide with a high melting temperature was synthesized from rac-lactide through an organocatalytic route using dimeric phosphazene base 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2 5,4 5-catenadi(phosphazene) (P2-t-Bu) catalyst at low temperature. Microstructural analysis of the prepared polymer using homodecoupled 1H NMR spectroscopy revealed the formation of a stereoblock architecture containing long isotactic sequence of R- and S- blocks in the main chain. A proposed mechanism involving chain-end control and stereoerror explains the stereoselective polymerization.

Zhang, Lei [Almaden Research Center; Nederberg, Fredrik [Almaden Research Center; Messman, Jamie M [ORNL; Pratt, Russel C [Almaden Research Center; Hedrick, James [Almaden Research Center; Wade, Charles G [Almaden Research Center

2007-01-01

20

Phosphazene-catalyzed intramolecular cyclization of nitrogen-tethered alkynyl esters.  

PubMed

Intramolecular cyclization of nitrogen-tethered alkynyl esters catalyzed by phosphazene organosuperbases P2-tBu and P4-tBu was investigated. Both acyclic and cyclic substrates underwent 5-exo-dig and 5-endo-dig cyclization. This reaction is a rare example of the intramolecular addition of enolates of simple esters to alkynes. PMID:24064956

Kondoh, Azusa; Ando, Kenichi; Terada, Masahiro

2013-10-01

21

Role of Ring Strain and Steric Hindrance in a New Method for Synthesis of Macrocyclic and High Polymeric Phosphazenes,  

National Technical Information Service (NTIS)

Ring strain induces the ring-opening polymerization of phosphazene trimers that bear no halogen substituents. This is of considerable importance because it had previously been assumed that side group halogen atoms were a prerequisite for access to the rin...

G. H. Riding J. A. Dodge H. R. Allcock

1989-01-01

22

Proton conducting membranes from sulfonated poly[bis(phenoxy)phosphazenes] with an interpenetrating hydrophilic network  

Microsoft Academic Search

Proton conducting membranes have been prepared using sulfonated poly[bis(phenoxy)phosphazene] (s-BPP) trapped in a cross-linked interpenetrating hydrophilic network of hexa(vinyloxyethoxyethoxy)cyclotriphosphazene (CVEEP). Membranes with good mechanical and thermal stabilities were obtained exhibiting high ion exchange capacities in the range of 1.62–1.79 mmol\\/g. The proton conductivity was measured as a function of water partial pressure in nitrogen (0 mbar to 25 mbar) in the temperature range

M. Burjanadze; J. Paulsdorf; N. Kaskhedikar; Y. Karatas; H.-D. Wiemhöfer

2006-01-01

23

Crystal structure and thermal transition behavior of poly[bis(phenoxy)phosphazene  

Microsoft Academic Search

The spherulitic crystal structure and thermal transition behavior of poly[bis(phenoxy)phosphazene] have been investigated using differential scanning calorimetry (DSC), polarized microscopy, X-ray diffraction, and thermal mechanical analysis. Polymer films were solution-cast from xylene over relatively wide crystallization and annealing ranges. Large-scale spherulites were created at a polymer concentration (in xylene) of 0.50 wt\\/vol% and a crystallization temperature of 80°C. One or

Hao Tang; P. N Pintauro

1999-01-01

24

Photochemical behavior of poly(organophosphazenes). XI. Photochemistry of poly[bis(4-benzylphenoxy) phosphazene  

Microsoft Academic Search

In this paper we present results on the photolysis of poly[bis(4-benzylphenoxy)-phosphazene] in solution and in film, both in the presence and in the absence of molecular oxygen. Light irradiation of the polymer in oxygen-saturated CH2Cl2 solutions results in a remarkable degradation of the polyphosphazene, while in argon-purged solutions no appreciable variations of the polymer structure could be detected. The photolysis

F. Minto; M. Gleria; M. Scoponi; F. Pradella; P. Bortolus

1992-01-01

25

Synthesis and Characterization of Cyclic and Linear Phosphazenes with Phosphorus-Sulfur Linkages  

SciTech Connect

Recent research at the INEEL has focused on the versatility inherent in polyphosphazene chemistry to membrane separations involving water transport through polymer materials.1 Polyphosphazenes, a hybrid organic and inorganic polymer, have been shown to be effective membranes in gas separation2 and liquid pervaporation applications.3 These characteristics are due to the inorganic nature of the backbone that provides these materials with remarkable chemical and mechanical stability. Additionally, phosphazene materials can be tailored to specific applications depending on the type of pendant groups that are attached to the phosphorus atoms of the backbone.

Luther, Thomas Alan; Harrup, Mason Kurt; Stewart, Frederick Forrest

2004-04-01

26

Photochemical behavior of poly(organophosphazenes). IX. Internal photostabilization effects in (4-benzoylphenoxy) x (?-naphthoxy) 2? x phosphazene copolymers  

Microsoft Academic Search

The synthesis and the photochemical behavior in solution and in films of a series of polyphosphazenes containing both benzophenone and naphthalene groups are described. The light energy absorbed by the benzophenone group is transferred to the naphthalene chromophore and wasted in photophysical processes which are not harmful to the polymer. This leads to a remarkable photostabilization of the benzophenone-containing phosphazene

Francesco Minto; Lucia Flamigni; Pietro Bortolus; Mario Gleria

1991-01-01

27

Synthesis of Poly(bis(phosphazo)phosphazenes) Bearing Aryloxy and Alkoxy Side Groups. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

The synthesis of a new class of phosphazene polymers through the thermalring-opening polymerization of 1,1-bis(trichloropho sphazo)tetrachlorocy clotriphosphazene, gem-(NPCl3)2N3P3Cl4 (1), is reported. The resultant polymer possesses controlled short-chai...

H. R. Allcock D. C. Ngo

1992-01-01

28

Surface Modification of Plasma-Treated Polyamide6 with Fluorinated Alcohols and Azobenzene Compounds using Chlorinated Phosphazenes as Coupling Agents  

Microsoft Academic Search

A three-step procedure for surface functionalization of polyamide-6 plates is presented. The substrate was first treated with cold, low pressure Ar plasma to generate surface OH groups, which were successively reacted with chlorophosphazenes to ensure grafting of these molecules. Substitution of the residual chlorines of the phosphazenes with fluorinated alcohols and 4-hydroxyazobenzene yielded the final surface modification. Characterization was performed

Roberto Milani; Mario Gleria; A. Sassi; R. De Jaeger; A. Mazzah; C. Jama; L. Gengembre

2008-01-01

29

Organometallic Phosphazenes: Synthesis and Rearrangement of Propynyl and Propadienyl Cyclotriphosphazenes.  

National Technical Information Service (NTIS)

Copper- or lithiophosphazene anions react with prop-2-ynyl bromide with the attachment fo the prop-2-ynyl group to the ring. Subsequent rearrangements yielded prop-1,2-dienyl or prop-1-ynyl derivatives. The mechanism of these reactions is discussed. These...

H. R. Allcock P. J. Harris R. A. Nissan

1980-01-01

30

On the Contributions to the Materials Science Aspects of Phosphazene Chemistry by Professor Christopher W. Allen: The One-Pot Synthesis of Linear Polyphosphazenes  

SciTech Connect

The wide range of applications for the phosphazene compounds has stimulated a major research effort involving several industrial, academic, and national laboratories over the past 40 years. One of Professor Allen’s research areas was to establish fundamental synthetic methods for the commercial preparation of phosphazene polymers, investigate their properties, and develop useful products. In this paper we review some of the materials science aspects of Professor Allen’s research including recent advances on the preparation and polymerization of Cl3PNP(O)Cl2. This work, in particular, has led to a route for the “one-pot” synthesis of stable linear poly(organophosphazenes) as demonstrated through the formation of poly[bis-(2-methoxyethoxyethoxy)phosphazene] (MEEP) and a phosphazene heteropolymer (HPP) containing a balance of hydrophilic and hydrophobic components that allow for control and molecular affinities.

Eric S. Peterson; Thomas A. Luther; Mason K. Harrup; John R. Klaehn; Mark L. Stone; Christopher J. Orme; Frederick F. Stewart

2007-06-01

31

Separations of hazardous organics from gas and liquid feedstreams using phosphazene polymer membranes  

SciTech Connect

The liquid-liquid and gas separation properties for the separation of hazardous organic feed streams using pervaporation and gas separation methods with poly[bis(phenoxy)phosphazene] based membranes are reported. Liquid transport behavior was determined using pervaporation techniques. The preliminary gas separations were studied using a mixed gas separation method which the authors have described previously. Using the membrane pervaporation technique, separation factors of 10,000 have been routinely achieved for the separation of methylene chloride from water. Other tests have shown similar results for the removal of hydrocarbon vapors from air. Membranes were prepared using solution casting techniques. Solvent evaporation rates during the casting and subsequent curing processes were controlled to provide a consistent membrane microstructure. These results suggest that polyphosphazene membrane technology could effectively be used in cleaning up air and ground water that has been contaminated with chlorinated hydrocarbons.

Peterson, E.S.; Stone, M.L.; Cummings, D.G.; McCaffrey, R.R. [Idaho National Engineering Lab., Idaho Falls (United States)

1993-01-01

32

Phosphazene Based Additives for Improvement of Safety and Battery Lifetimes in Lithium-Ion Batteries  

SciTech Connect

There need to be significant improvements made in lithium-ion battery technology, principally in the areas of safety and useful lifetimes to truly enable widespread adoption of large format batteries for the electrification of the light transportation fleet. In order to effect the transition to lithium ion technology in a timely fashion, one promising next step is through improvements to the electrolyte in the form of novel additives that simultaneously improve safety and useful lifetimes without impairing performance characteristics over wide temperature and cycle duty ranges. Recent efforts in our laboratory have been focused on the development of such additives with all the requisite properties enumerated above. We present the results of the study of novel phosphazene based electrolytes additives.

Mason K Harrup; Kevin L Gering; Harry W Rollins; Sergiy V Sazhin; Michael T Benson; David K Jamison; Christopher J Michelbacher

2011-10-01

33

Reactions of lithiated P-diphenyl(alkyl)( N-methoxycarbonyl)phosphazenes with Michael acceptors and aldehydes. Synthesis of 1 H-1,2-azaphosphinin-6-ones, ?-hydroxy( N-methoxycarbonyl)phosphazenes and 5,6-dihydro-1,3,4-oxazaphosphinin-2-ones  

Microsoft Academic Search

Lithium (N-methoxycarbonyl)phosphazenes add C-regioselectively to DMAD, dimethyl malonate, fumarate, and butylidenmalonate in a [1,4] manner. Only one diastereoisomer is observed with the olefinic electrophiles. With DMAD the initial adduct evolves through cyclocondensation with the CO2Me group of the phosphazene and 1H-1,2-azaphosphinin-6-ones are obtained. Exceptionally, methyl phenylpropiolate reacted exclusively through the carbonyl yielding a mixture of C- and N-acylated compounds. The

Julia M Álvarez-Gutiérrez; Emma Peralta-Pérez; Isidro Pérez-Álvarez; Fernando López-Ortiz

2001-01-01

34

Surface Functionalization with Phosphazenes: Part 6. Modification of Polyethylene Co -Polyvinylalcohol Copolymer Surface Plates with Fluorinated Alcohols and Azobenzene Derivatives Using Chlorinated Phosphazenes as Coupling Agents  

Microsoft Academic Search

In this paper we describe a two-step surface modification process of poly(ethylene-co-vinyl alcohol) by exploiting hexachlorocyclophosphazene and poly(dichlorophosphazene) as coupling agents. Part of the P–Cl\\u000a groups of the chlorophosphazenes is first reacted with the surface hydroxylic groups of the substrate to form covalent P–O–C\\u000a bonds, the remaining being utilized for successive substitution reactions with different nucleophiles (i.e. 2,2,2-trifluoroethanol,\\u000a heptadecafluorononanol and

Roberto Milani; Mario Gleria; Silvia Gross; Roger De Jaeger; Ahmed Mazzah; Leon Gengembre; Martine Frere; Charafeddine Jama

2008-01-01

35

Oxazoline-containing phosphazene derivatives. Part I: the case of hexakis(4-oxazolinophenoxy)cyclophosphazene  

Microsoft Academic Search

In this paper, the synthesis, characterization, and reactivity of a novel oxazoline-containing cyclophosphazene, hexakis(4-oxazolinophenoxy)cyclophosphazene, C-6-OXA, are reported. This product was synthesized by a two-step procedure that required first the preparation of 2-(4-hydroxyphenyl)-2-oxazoline and then the successive treatment of this compound with hexachlorocyclophosphazene in the presence of NaH (60% oil dispersion). The resulting C-6-OXA was eventually reacted with low-molecular-weight organic molecules,

Mario Gleria; Francesco Minto; Barbara Tiso; Roberta Bertani; Eugenio Tondello; Riccardo Pò; Luisa Fiocca; Emilio Lucchelli; Giorgio Giannotta; Nicoletta Cardi

2001-01-01

36

Biodegradable Poly(2-Dimethylamino Ethylamino)Phosphazene for In Vivo Gene Delivery to Tumor Cells. Effect of Polymer Molecular Weight  

Microsoft Academic Search

Purpose  Previously, we have shown that complexes of plasmid DNA with the biodegradable polymer poly(2-dimethylamino ethylamino)phosphazene\\u000a (p(DMAEA)-ppz) mediated tumor selective gene expression after intravenous administration in mice. In this study, we investigated\\u000a the effect of p(DMAEA)-ppz molecular weight on both in vitro and in vivo tumor transfection, as well as on complex induced toxicity.\\u000a \\u000a \\u000a \\u000a Materials and Methods  p(DMAEA)-ppz with a broad molar

Holger K. de Wolf; Markus de Raad; Cor Snel; Mies J. van Steenbergen; Marcel H. A. M. Fens; Gert Storm; Wim E. Hennink

2007-01-01

37

In vivo tumor transfection mediated by polyplexes based on biodegradable poly(DMAEA)-phosphazene.  

PubMed

In recent years, increasing interest is being paid to the design of transfectants based on non-toxic and biodegradable polymers for gene therapy purposes. We recently reported on a novel, biodegradable polymer, poly(2-dimethylamino ethylamino)phosphazene (p(DMAEA)-ppz) for use in non-viral gene delivery. In this study, the biodistribution and in vivo transfection efficiency of polyplexes composed of plasmid DNA and p(DMAEA)-ppz were investigated after intravenous administration in tumor bearing mice. Data were compared with those of polyplexes based on the non-biodegradable polyethylenimine (PEI 22kDa). Both polyplex systems were rapidly cleared from the circulation (<7% ID, at 60 min after administration) and showed considerable disposition in the liver and the lung, all in line with earlier work on cationic polyplex systems. The lung disposition is attributed to aggregates formed by interaction of the polyplexes with blood constituents. Redistribution of the polyplexes from the lung was observed for both polyplex formulations. Importantly, both polyplex systems showed a substantial tumor accumulation of 5% and 8% ID/g for p(DMAEA)-ppz and PEI22 polyplexes, respectively, at 240 min after administration. The tumor disposition of the p(DMAEA)-ppz and PEI22 polyplexes was associated with considerable expression levels of the reporter gene. In contrast to PEI22 polyplexes, p(DMAEA)-ppz polyplexes did not display substantial gene expression in the lung or other organs (organ gene expression<1/100 of tumor gene expression). The observed preferential tumor gene expression mediated by the p(DMAEA)-ppz polyplexes enables the application of this polymer to deliver therapeutic genes to tumors. PMID:16039747

de Wolf, Holger K; Luten, Jordy; Snel, Cor J; Oussoren, Christien; Hennink, Wim E; Storm, Gert

2005-07-21

38

Synthesis of Potential Purinoceptor Antagonists: Application of P1tBu Phosphazene Base for Alkylation of Adenine in Solution and on Solid Phase  

Microsoft Academic Search

Alkylation of adenine in solution and on solid phase was accelerated by phosphazene base P1-tBu compared to mineral bases. The reactions in solution afforded regioselectively the appropriate N9-alkylated adenines with high preparative yields while the reaction with polystyrene resin-bound N-bromoacetylated peptides gave three regioisomers (alkylated at the N9, N7, and N3 position of adenine) in a 4:2:1 molar ratio. Ten

Erki Enkvist; Gerda Raidaru; Asko Uri; Roshni Patel; Catherine Redick; José L. Boyer; Juhan Subbi; Indrek Tammiste

2006-01-01

39

New materials based on the reaction of cyclo- and poly-(organo phosphazenes) with SiO 2 , TiO 2 and ZrO 2 precursors  

Microsoft Academic Search

A new class of organic-inorganic materials can be prepared, based on inorganic networks and cycloor poly-(organophosphazenes). Poly(organophosphazenes) are polymers characterized by many interesting technological properties. This report is based on a investigation on the reactivity of SiO2, TiO2 and ZrO2 precursors with different phosphazene compounds functionalized with hydroxyl groups, to prepare materials with a hybrid structure. The synthesis of these

M. Guglielmi; P. Colombo; G. Brusatin; G. Facchin; M. Gleria

1994-01-01

40

Synthesis of potential purinoceptor antagonists: application of P1-tBU phosphazene base for alkylation of adenine in solution and on solid phase.  

PubMed

Alkylation of adenine in solution and on solid phase was accelerated by phosphazene base P1-tBu compared to mineral bases. The reactions in solution afforded regioselectively the appropriate N9-alkylated adenines with high preparative yields while the reaction with polystyrene resin-bound N-bromoacetylated peptides gave three regioisomers (alkylated at the N9, N7, and N3 position of adenine) in a 4:2:1 molar ratio. Ten novel nonphosphate nucleotide analogues were tested in an ADP-induced platelet aggregation assay. PMID:16541958

Enkvist, Erki; Raidaru, Gerda; Uri, Asko; Patel, Roshni; Redick, Catherine; Boyer, José L; Subbi, Juhan; Tammiste, Indrek

2006-01-01

41

Molecular dynamics simulations of polyphosphazenes: poly[bis(chloro)phosphazene][NPCl 2 ] n  

Microsoft Academic Search

Suitable parameter sets for the CHARMm force field were derived for the structural units in polychlorophosphazene [P=N, P N, P Cl] using the Dinur Hagler energy second derivative procedure based on quantum mechanical SCI calculations using the 6–31G* basis set. To validate the reliability of the parameter set, structural results obtained with CHARMm for the adopted model compounds (OP2NCl5 and

Maria E. Amato; Antonio Grassi; Kenny B. Lipkowitz; Giuseppe M. Lombardo; Giuseppe C. Pappalardo; Claudia Sadun

1996-01-01

42

Supramolecular rods via halogen bonding-based self-assembly of fluorinated phosphazene nanopillars  

Microsoft Academic Search

A cyclotriphosphazene derivative bearing six 4-iodotetrafluorophenyl-substituted arms self-assembles with dipyridyl derivatives under the control of N?I halogen bonding to give rise to complexes where the starting modules are present in a 1:3 stoichiometric ratio, respectively. The directionality of the N?I halogen bonding translates the pillar-like arrangement adopted by the cyclotriphosphazene module into the rod-shaped supramolecular structure of the formed infinite

Roberta Bertani; Fanny Chaux; Mario Gleria; Pierangelo Metrangolo; Roberto Milani; Tullio Pilati; Giuseppe Resnati; Maurizio Sansotera; Alfonso Venzo

2007-01-01

43

Biodegradable Poly(2-Dimethylamino Ethylamino)Phosphazene for In Vivo Gene Delivery to Tumor Cells. Effect of Polymer Molecular Weight  

PubMed Central

Purpose Previously, we have shown that complexes of plasmid DNA with the biodegradable polymer poly(2-dimethylamino ethylamino)phosphazene (p(DMAEA)-ppz) mediated tumor selective gene expression after intravenous administration in mice. In this study, we investigated the effect of p(DMAEA)-ppz molecular weight on both in vitro and in vivo tumor transfection, as well as on complex induced toxicity. Materials and Methods p(DMAEA)-ppz with a broad molar mass distribution was fractionated by preparative size exclusion chromatography. Polyplexes consisting of plasmid DNA and the collected polymer fractions were tested for biophysical properties, (cyto)toxicity and transfection activity. Results Four p(DMAEA)-ppz fractions were collected with weight average molecular weights ranging from 130 to 950 kDa, and with narrow molecular mass distributions (Mw/Mn from 1.1 to 1.3). At polymer-to-DNA (N/P) ratios above 6, polyplexes based on these polymers were all positively charged (zeta potential 25–29 mV), and had a size of 80–90 nm. The in vitro cytotoxicity of the polyplexes positively correlated with polymer molecular weight. The in vitro transfection activity of the different polyplexes depended on their N/P ratio, and was affected by the degree of cytotoxicity, as well as the colloidal stability of the different polyplexes. Intravenous administration of polyplexes based on the high molecular weight polymers led to apparent toxicity, as a result of polyplex-induced erythrocyte aggregation. On the other hand, administration of polyplexes based on low molecular weight p(DMAEA)-ppz’s (Mw 130 kDa) did not show signs of toxicity and resulted in tumor selective gene expression. Conclusion Polymer molecular weight fractionation enabled us to optimize the transfection efficiency/toxicity ratio of p(DMAEA)-ppz polyplexes for in vitro and in vivo tumor transfection.

de Wolf, Holger K.; de Raad, Markus; Snel, Cor; van Steenbergen, Mies J.; Fens, Marcel H. A. M.; Storm, Gert

2007-01-01

44

Structural characterization of new fungicidal material; complexes of copper(II) with cyclic phosphazenes  

Microsoft Academic Search

Hexaethylamino- and hexabenzylamino- derivatives of cyclotriphosphazene were prepared by substituting the chlorine atoms of hexachlorocyclotriphosphazene. A number of addition complexes of copper(II) acetate were then prepared with these cyclophosphazene ligands in different stoichiometric ratios. The complexes have been characterized on the basis of analytical and physico — chemical studies. The molar conductance measurements suggest the complexes are non - electrolytes.

B. P. Baranwal; S. S. Das; Umme Farva

2002-01-01

45

Effect of adding new phosphazene compounds to poly(butylene terephthalate)\\/polyamide blends. I: Preliminary study in a batch mixer  

Microsoft Academic Search

Poly(butylene terephthalate) (PBT) and a sample of polyamide have been melt processed in the presence of two new phosphazene compounds, namely 2,2-dichloro-4,4,6,6-bis[spiro(2?,2?dioxy-1?,1?biphenyl)]cyclotriphosphazene (2Cl-CP) and 2,2-bis-(2-methoxy-4-methyleneoxy-phenoxy)-4,4,6,6,-bis[spiro(2?,2?dioxy-1?,1?biphenyl)]cyclophosphazene (CP-2EPOX).The blends were prepared by using polyamide 6 (PA6) at 25\\/75w\\/w and 75\\/25w\\/w composition. In order to perform a preliminary analysis on the behaviour of the blends, the materials were prepared in a batch mixer.The

R. Scaffaro; L. Botta; F. P. La Mantia; P. Magagnini; D. Acierno; M. Gleria; R. Bertani

2005-01-01

46

Effect of adding new phosphazene compounds to poly(butylene terephthalate)\\/polyamide blends. II: Effect of different polyamides on the properties of extruded samples  

Microsoft Academic Search

Poly(butylene terephthalate) (PBT) and a sample of polyamide have been melt processed in the presence of two new phosphazene compounds, namely 2,2-dichloro-4,4,6,6-bis[spyro(2?,2?-dioxy-1?,1?-biphenyl)]cyclotriphosphazene (2Cl-CP) and 2,2-bis(2-methoxy-4-methyleneoxy-phenoxy)-4,4,6,6-bis[spyro(2?,2?-dioxy-1?,1?-biphenyl)]cyclophosphazene (CP-2EPOX).The blends were prepared by using polyamide 6 (PA6) and polyamide 6,6 (PA66) in 25\\/75 and 75\\/25w\\/w compositions by using a co-rotating twin-screw extruder.The materials have been completely characterized from a mechanical, rheological, and morphological

R. Scaffaro; L. Botta; F. P. La Mantia; M. Gleria; R. Bertani; F. Samperi; G. Scaltro

2006-01-01

47

Miscibility and in vitro osteocompatibility of biodegradable blends of poly[(ethyl alanato) (p-phenyl phenoxy) phosphazene] and poly(lactic acid-glycolic acid)  

PubMed Central

Previously we demonstrated the ability of ethyl glycinato substituted polyphosphazenes to neutralize the acidic degradation products and control the degradation rate of poly(lactic acid-glycolic acid) by blending. In this study, blends of high strength poly[(50% ethyl alanato) (50% p-phenyl phenoxy) phosphazene] (PNEA50PhPh50) and 85:15 poly(lactic acid-glycolic acid) (PLAGA) were prepared using a mutual solvent approach. Three different solvents, methylene chloride (MC), chloroform (CF) and tetrahydrofuran (THF) were studied to investigate solvent effects on blend miscibility. Three different blends were then fabricated at various weight ratios namely 25:75 (BLEND25), 50:50 (BLEND50), and 75:25 (BLEND75) using THF as the mutual solvent. The miscibility of the blends was evaluated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). Among these, BLEND25 was miscible while BLEND50 and BLEND75 were partially miscible. Furthermore, BLEND25 formed apatite layers on its surface as evidenced in a biomimetic study performed. These novel blends showed cell adhesion and proliferation comparable to PLAGA. However, the PNEA50PhPh50 component in the blends was able to increase the phenotypic expression and mineralized matrix synthesis of the primary rat osteoblasts (PRO) in vitro. Blends of high strength poly[(50% ethyl alanato) (50% p-phenyl phenoxy) phosphazene] (PNEA50PhPh50) and 85:15 poly(lactic acid-glycolic acid) (PLAGA) are promising biomaterials for a variety of musculoskeletal applications.

Deng, Meng; Nair, Lakshmi S.; Nukavarapu, Syam P.; Kumbar, Sangamesh G.; Jiang, Tao; Krogman, Nicholas R.; Singh, Anurima; Allcock, Harry R.; Laurencin, Cato T.

2007-01-01

48

Aspects of Phosphazene Research  

Microsoft Academic Search

This review reports research carried out by the authors during the last 10 years. The research involves the synthesis, characterization, functionalization, and possible utilization of cyclo- and polyphosphazenes. The investigations concern the synthesis of poly(dichlorophosphazene) by polycondensation reaction of dichlorophinoyliminotrichlorophosphorane; the grafting of unsaturated organic substrates (maleic anhydride, maleates or vinyl polymers) onto poly(organophosphazenes) by free radical reactions and the

Mario Gleria; Roger De Jaeger

2001-01-01

49

Polyphosphazenes: A Review  

Microsoft Academic Search

In this paper the synthesis, properties and applications of poly(organophosphazenes) have been highlighted. Five different classes of macromolecules have been described, i.e. phosphazene fluoroelastomers, aryloxy-substituted polymeric flame-retardants, alkoxy-substituted phosphazene electric conductors, biomaterials and photo-inert and\\/or photo-active phosphazene derivatives. Perspectives of future developments in this field are briefly discussed.

Mario Gleria; Roger De Jaeger

50

Poly(Phosphazene) Wire and Cable Insulation.  

National Technical Information Service (NTIS)

The objective of the program under Contract No. N00024-78-C-4644 is to prepare a fire resistant cable utilizing a single poly(aryloxyphosphazene) (firestone APN(trademark)) base material for both the wire insulation and the cable jacket. Formulations will...

T. C. Peterson

1979-01-01

51

Betulinol derivatives  

US Patent & Trademark Office Database

The present invention is directed to betulinol derivatives and betulinol-antibody conjugates having the formulae: ##STR1## and and, in particular, betulinol dimethyl ether. Methods for making and using these derivatives and conjugates, as well as a method for making and using betulonic aldehyde, are also disclosed.

Bomshteyn; Arkadiy L. (Brooklyn, NY); Rathnam; Premila (Englewood Cliffs, NJ); Saxena; Brij B. (Englewood, NJ)

2005-05-10

52

Complex derivatives  

NASA Astrophysics Data System (ADS)

The intrinsic complexity of the financial derivatives market has emerged as both an incentive to engage in it, and a key source of its inherent instability. Regulators now faced with the challenge of taming this beast may find inspiration in the budding science of complex systems.

Battiston, Stefano; Caldarelli, Guido; Georg, Co-Pierre; May, Robert; Stiglitz, Joseph

2013-03-01

53

Glycal Derivatives  

NASA Astrophysics Data System (ADS)

Glycals are unsaturated sugar derivatives in which the double bond engages the anomeric carbon atom. Such cyclic vinyl ethers are characterized by high reactivity, allowing for regio- and stereoselective transformations, directly or indirectly related to glycosylation, as well as to formation of carbon-carbon and carbon-heteroatom bonds at the anomeric center. This review provides a systematic survey of chemical synthetic methods, by which the carbon-carbon double bond is introduced next to the ring oxygen, in an endo- or exocyclic position. Some mechanistic aspects are discussed in relation to traditional methods of glycal preparation, which rely on elimination reactions. Glycal-to-glycal rearrangement and applications of organometallic chemistry and heteroatom-induced transformations for syntheses and activation of glycals are also highlighted.

Priebe, Waldemar; Fokt, Izabela; Grynkiewicz, Grzegorz

54

Raman spectroscopic study of a substituted poly(phosphazene)  

Microsoft Academic Search

Polyphosphazenes present a range of unique and fascinating physical properties, including thermotropic behaviour, which are highly dependent both on the type of substitution at the P atom in the inorganic backbone, and the thermal history of the material. Recent technological advances have allowed us to study this group of polymers using vibrational spectroscopy. Fourier transform (FT) Raman spectra have been

Gary Ellis; M. Angeles Gómez; Carlos Marco; José G. Fatou; Robert C. Haddon

1991-01-01

55

Weather Derivative Valuation  

NASA Astrophysics Data System (ADS)

Weather Derivative Valuation is the first book to cover all the meteorological, statistical, financial and mathematical issues that arise in the pricing and risk management of weather derivatives. There are chapters on meteorological data and data cleaning, the modelling and pricing of single weather derivatives, the modelling and valuation of portfolios, the use of weather and seasonal forecasts in the pricing of weather derivatives, arbitrage pricing for weather derivatives, risk management, and the modelling of temperature, wind and precipitation. Specific issues covered in detail include the analysis of uncertainty in weather derivative pricing, time-series modelling of daily temperatures, the creation and use of probabilistic meteorological forecasts and the derivation of the weather derivative version of the Black-Scholes equation of mathematical finance. Written by consultants who work within the weather derivative industry, this book is packed with practical information and theoretical insight into the world of weather derivative pricing.

Jewson, Stephen; Brix, Anders

2005-04-01

56

Isotopomeric water separations with supported polyphosphazene membranes  

Microsoft Academic Search

Poly[bis(phenoxy)phosphazene] and several carboxylated derivatives were examined for use as membranes to separate tritiated water and deuterated water from light water. The polyphosphazenes were solvent cast from dioxane onto a support material of polyethylene terephthalate. These membranes were tested with water containing 10 pCi\\/ml tritiated water or 10 wt% deuterated water under dead-end filtration conditions.Poly[bis(phenoxy)phosphazene] provided separation of tritiated water

David A. Nelson; James B. Duncan; George A. Jensen; Sarah D. Burton

1996-01-01

57

Neuroprotective Ganglioside Derivatives.  

National Technical Information Service (NTIS)

In this study, neuroprotective ganglioside derivatives are studied in an attempt to devise neuroprotective agents targeted to specific points in cell death pathways. GMl ganglioside and several of its chemically modified derivatives are neuroprotective in...

M. D. Ullman

2004-01-01

58

Mesomorphic Derivatives Of Ferrocene  

Microsoft Academic Search

The first series of ferrocene derivatives exhibiting mesomorphic properties (substituted N-(p-benzoyloxybenzylidene) anilines la and 1b) has been synthesized for application in Mössbauer spectroscopy.

Jacques Malthete; Jean Billard

1976-01-01

59

Irregularities in Imperfective Derivation  

ERIC Educational Resources Information Center

|This article discusses presentation of Russian conjugation via the one-stem system advocated by Lipson and Townsend, and attempts a more unified and complete presentation of irregularities in imperfect derivation. Two major irregularities are occurrence of an unexpected suffix and unpredictable alternation in the root of the derived imperfective.…

Levin, Maurice I.

1977-01-01

60

Higher Derivative Gravity.  

National Technical Information Service (NTIS)

A possible classical route conducting towards a general relativity theory with higher-derivatives starting, in a sense, from first principles, is analysed. A completely causal vacuum solution with the symmetries of the Goedel universe is obtained in the f...

A. J. Accioly

1987-01-01

61

Ferrocene and Ferrocene Derivatives.  

National Technical Information Service (NTIS)

This is an annotated bibliography covering ferrocene and its derivatives from 1962 to August 1966. Several review articles are listed which describe the unique characteristics of ferrocene since its discovery in 1951, its reactions, and some of its uses. ...

W. P. McNutt C. U. Pittman

1966-01-01

62

Neuroprotective Ganglioside Derivatives.  

National Technical Information Service (NTIS)

In this study, neuroprotective ganglioside derivatives are examined so they can be targeted to specific points in cell death pathways. Here, ganglioside functional groups required for neuroprotection and blood-brain barrier permeance are determined. Cell ...

M. D. Ullman

2003-01-01

63

Deriving Common Model Characteristics  

NSDL National Science Digital Library

In this activity, students confront several different models - from the DNA helix Watson and Crick constructed in their laboratory to a map of McDonalds density in the US - and work in small groups to derive their commonalities.

Momsen, Jennifer; Long, Tammy M.; Speth, Elena B.

64

Combinatorics of Partial Derivatives  

Microsoft Academic Search

The natural forms of the Leibniz rule for the kth derivative of a product and of Fa a di Bruno's formula for the kth derivative of a composition involve the dif- ferential operator @k=@x1 @xk rather than dk=dxk, with no assumptions about whether the variables x1;:::;xk are all distinct, or all identical, or partitioned into several distinguishable classes of indistinguishable

Michael Hardy

2006-01-01

65

On higher derivative gravity  

Microsoft Academic Search

A possible classical route conducting towards a general relativity theory with higher-derivatives starting, in a sense, from first principles, is analysed. A completely causal vacuum solution with the symmetries of the Goedel universe is obtained in the framework of this higher-derivative gravity. This very peculiar and rare result is the first known vacuum solution of the fourth-order gravity theory that

A. J. Accioly

1987-01-01

66

Derivative beliefs and evaluations  

Microsoft Academic Search

Purpose – The purpose of this research is to examine how consumers form beliefs and evaluate derivatives (e.g. handheld computers) and branded derivatives (e.g. Palm handheld computers). The aim is to study how consumers combine two categories (e.g. “handheld products” and “computers”) to form beliefs, how the similarity between the categories influences beliefs, how the addition of a brand changes

Daniel A. Sheinin; Laurette Dubé; Bernd H. Schmitt

2008-01-01

67

Semisynthetic Derivatives of Epothilones  

NASA Astrophysics Data System (ADS)

Semisynthetic derivatives of natural products traditionally occupy a prominent space in natural-product-based drug discovery (1, 2). As many biologically active natural products exhibit a high degree of structural complexity (3), the chemical derivatization of material isolated from natural sources often represents the only feasible means (or at least the only economically viable approach) to explore structure-activity-relationships (SAR) and to produce analogs with more favorable pharmacokinetic and pharmacological properties than the natural product lead. Examples of clinically important drugs that are semisynthetic derivatives of natural products exist in virtually all disease areas (1, 2); in the treatment of cancer this includes compounds such as etoposide or teniposide (derived from podophyllotoxin) (4-6), irinotecan and topotecan (derived from camptothecin) (7-9), or docetaxel (derived from 10-deacetylbaccatin III) (10, 11). Even for taxol (11), which is a natural product (12), the sustained supply of sufficient quantities of material for widespread clinical use could only be secured through the development of a semisynthetic production process from another natural product, namely, 10-deacetylbaccatin III (13). In light of these facts, it is not surprising that semisynthesis approaches have also featured prominently in the elucidation of the SAR for epothilones and in the discovery of a number of clinical development candidates.

Altmann, Karl-Heinz

68

Epoxide-derived organosulfates  

NASA Astrophysics Data System (ADS)

Organosulfates (OS) are a significant fraction of secondary organic aerosol (SOA) material in the atmosphere. OS are typically surface-active, and have been suggested to cause surface tension depression in aerosols. Recent field studies suggest that epoxide-derived OS are the most abundant OS type in aerosols. Time-dependent surface tension measurements and Aerosol-CIMS characterization of two epoxides and their organosulfate products are shown. ?-pinene oxide, derived from ?-pinene, shows significant surface tension depression in H2O and ammonium sulfate. Results from cis-2,3-epoxybutane-1,4-diol (BEPOX), a butadiene-derived analog to isoprene-derived epoxydiols, are also shown. In addition, using GAMMA, a photochemical box model using coupled gas- and aqueous-phase chemistry developed in the McNeill laboratory, we show the dominance of epoxide-derived OS formation over other competing OS formation mechanisms, such as radical chemistry, under both high-NOx and low-NOx scenarios.

Schwier, A. N.; Woo, J.; McNeill, V. F.

2011-12-01

69

Crosslinkable cellulose derivatives  

SciTech Connect

This patent describes a method for treating a subterranean formation. It comprises: preparing a treating fluid composition with or without a particulate agent by admixing an aqueous liquid, a cellulose ether derivative consisting essentially of the reaction product of a cellulose ether with a ceric salt, the reaction occurring under acidic conditions and at a temperature in the range of from about 20{degree} to about 60{degree}C. and a cross-linking agent; and injecting the treating fluid composition into the subterranean formation through a wellbore. This patent also describes a method of treating a subterranean formation. It comprises: preparing a treating fluid composition with or without a particulate agent by admixing an aqueous liquid, a cellulose ether derivative that is chemically modified by reacting under acidic conditions the cellulose ether derivative with a vinyl phosphonic acid and a ceric salt, and a crosslinking agent; and injecting the treating fluid composition into the subterranean formation through a wellbore.

Holtmeyer, M.D.; Hunt, C.V.; Harms, W.M.

1991-01-08

70

Novel derivatives of polymyxins.  

PubMed

Polymyxin B and colistin (polymyxin E) are bactericidal pentacationic lipopeptides that act specifically on Gram-negative bacteria, first by disrupting their outermost permeability barrier, the outer membrane (OM), and then damaging the cytoplasmic membrane. Both were discovered in the mid-1950s and subsequently used in intravenous therapy, but soon largely abandoned because of nephrotoxicity. The emergence of extremely multiresistant strains has now forced clinicians to reinstate them in the therapy of severe infections caused by such strains. This article reviews recent attempts to develop novel derivatives of polymyxins that exhibit less toxicity and greater potency than the existing drugs. In addition, studies of novel des-fatty acyl-polymyxin derivatives that display activity against Pseudomonas aeruginosa are included. The review also covers recent studies of derivatives that lack potent bactericidal action, but which disrupt the OM, which increases bacterial permeability to other antibiotics, facilitating their entry into the cell. PMID:23412346

Vaara, Martti

2013-02-13

71

Myeloid derived suppressor cells  

PubMed Central

The goal of achieving measurable response with cancer immunotherapy requires counteracting the immunosuppressive characteristics of tumors. One of the mechanisms that tumors utilize to escape immunosurveillance is the activation of myeloid derived suppressor cells (MDSCs). Upon activation by tumor-derived signals, MDSCs inhibit the ability of the host to mount an anti-tumor immune response via their capacity to suppress both the innate and adaptive immune systems. Despite their relatively recent discovery and characterization, anti-MDSC agents have been identified, which may improve immunotherapy efficacy.

Waldron, Todd J.; Quatromoni, Jon G.; Karakasheva, Tatiana A.; Singhal, Sunil; Rustgi, Anil K.

2013-01-01

72

Crosslinkable cellulose derivatives  

SciTech Connect

This paper reports method of treating a subterranean formation. It comprises: preparing a treating fluid composition with or without a particulate agent by admixing: an aqueous liquid, a cellulose ether derivative that is chemically modified by reacting the cellulose ether derivative with a vinyl phosphonic acid in the presence of the reaction product of hydrogen peroxide and a ferrous salt and a crosslinking agent; and injecting the treating fluid composition into the subterranean formation through a wellbore; injecting the treating fluid composition into the subterranean formation through a wellbore.

Holtmyer, M.; Hunt, C.V.

1991-11-26

73

Credit Derivatives and Risk Management.  

National Technical Information Service (NTIS)

The striking growth of credit derivatives suggests that market participants find them to be useful tools for risk management. I illustrate the value of credit derivatives with three examples. A commercial bank can use credit derivatives to manage the risk...

M. S. Gibson

2007-01-01

74

Deriving Function From Structure  

Microsoft Academic Search

\\u000a The fold and biochemical activity of a protein are tightly coupled. Once a protein is characterized, it is usual to determine\\u000a its structure in order to derive an atomic descrip- tion of its molecular mechanism. The fold reveals interaction surfaces,\\u000a ligand-binding pockets, and the precise juxtaposition of functional groups.

Annabel E. Todd

75

Deriving Darcy's Law  

NSDL National Science Digital Library

This exercise begins with a demonstration of fluid flow through porous sediment using a constant head permeameter, with the students conducting the experiment and collecting the data. The demo is followed by a Think-Pair-Share exercise in which the question is posed to the class: "What could we change in order to increase flow through the system?" The class then works through their brainstormed list of ideas, discussing each and evaluating whether it is correct or a misconception. The students derive Darcy's Law qualitatively, based upon the results of the Think-Pair-Share exercise and discussions.

Salvage, Karen

76

Adipose-derived cells.  

PubMed

Heart failure is by far the most common cause of hospitalization in Western countries, with onerous economic consequences. Cell therapy holds great promise for use in tissue regeneration and is increasingly used in an effort to improve outcomes in cardiac disease. Recently it has been shown that adipose tissue, in addition to committed adipogenic, endothelial progenitor cells and pluripotent vascular progenitor cells, also contains multipotent cell types (adipose-derived stem cells, ADSCs) that, in cell culture conditions, have shown to have an impressive developmental plasticity including the ability to undergo multilineage differentiation and self-renewal. ADSCs express multiple CD marker antigens similar to those observed on MSCs and are also capable of secreting a large number of angiogenesis-related cytokines, including vascular endothelial growth factor, granulocyte/macrophage colony stimulating factor, stromal-derived factor-1alpha, and hepatocyte growth factor. Adipose tissue can be harvested in large quantities with minimal morbidity in several regions of the body and, on average, 100 ml of human adipose tissue yields about 1 x 10(6) stem cells. Studies conducted in porcine AMI models have shown a significant LV functional improvement, with no report of any potentially fatal arrhythmias. The APOLLO trial, a prospective, double blind, randomized, placebo-controlled trial currently in the recruiting phase, is a "first-in-man" study that explores the safety and feasibility of ADSC transplantation in patients with acute MI. PMID:18293895

Meliga, Emanuele; Strem, Brian M; Duckers, H J; Serruys, Patrick W

2007-01-01

77

Inositol derivatives: evolution and functions  

Microsoft Academic Search

Current research on inositols mainly focuses on myo-inositol (Ins) derivatives in eukaryotic cells, and in particular on the many roles of Ins phospholipids and polyphosphorylated Ins derivatives. However, inositols and their derivatives are more versatile than this — they have acquired diverse functions over the course of evolution. Given the central involvement of primordial bacteria and archaea in the emergence

Robert H. Michell

2008-01-01

78

Derivative Analysis of Hyperspectral Data  

Microsoft Academic Search

With the goal of applying derivative spectral analysis to analyze high-resolution, spectrally continuous remote sensing data, several smoothing and derivative computation algorithms have been reviewed and modified to develop a set of cross-platform spectral analysis tools. Emphasis was placed on exploring different smoothing and derivative algorithms to extract spectral details from spectral data sets. A modular program was created to

Fuan Tsai; William Philpot

1998-01-01

79

Derivative spectrophotometry of cobalt alloys  

Microsoft Academic Search

The method of derivative spectrophotometry is briefly described, and derivative absorption spectra are presented for samarium, cobalt, and commercial Sm-Co alloys. It is shown that the use of derivative spectrophotometry not only improves the accuracy and selectivity of element determinations but also simplifies the analysis of alloys. Results of a statistical evaluation of the metrological characteristics of the analytical procedure

Spitsyn

1985-01-01

80

Effects of Alkyl Substitution on the Physical Properties and Gas Transport Behavior in Selected Poly(R-phenoxyphosphazenes)  

SciTech Connect

A systematic preparation of alkyl substituted phenoxy-phosphazene polymers was performed. In this study, phosphazenes substituted with 4-methylphenol, 4-ethylphenol, and 4-isopropylphenol are reported. An additional polymer substituted with 4-tert-butylphenoxy-1-ethanol also was synthesized in this work. Data derived for these materials, including chemical, thermal and gas transport characterization, were compared to previous reports discussing poly[bis-phenoxyphosphazene] and its analog with tert-butyl substitution: poly[bis-(4-tert-butylphenoxy)phosphazene]. The tert-butyl moiety influences orderly chain packing, presumably through steric hindrance that can influence aromatic p-stacking. For the new poly[(alkylphenoxy)phosphazenes], semi-crystallinity is maintained and the added steric bulk serves to decrease the Tg and increase both permeability and selectivity for the gas pairs: O2/N2 and CO2/CH4. Removal of the tert-butyl moiety from the immediate vicinity of the backbone through a flexible spacer serves to depress the Tg as compared to poly[bis-(4-tert-butylphenoxy)phosphazene], but provides no performance enhancement for gas transport.

Mark D. Ogden; Christopher J. Orme; Frederick F. Stewart

2011-08-01

81

Tripyrroledimethine-derived  

Microsoft Academic Search

The syntheses of three new cadmium(II)-containing tripyrroledimethine-derived, 'texaphyrin'-type, macrocycles, 14,15-dicyano-4,5,9,20-tetraethyl-10,19-dimethyl-13,16,21,22,23- pentazatetracyclo[16.2 .1.13,6.18,11]tricosa-1,3,5,7,9,11(23)12,14,16,18(21),19-undecaene (1), 4,5,9,28-tetraethyl-10,27-dimethyl-13,24,29,30,31- pentaazahexaacyclo$B24.2.1.13,6. 18,11.014,23.016,21]-hentriaconta-1,,5,7,9,11(31),12,14(23),15,17,19, 21,24,26(29),27-pentadecaene (2), and 4,5,9,32-tetraethyl-10,31-dimethyl-13,28,33,34,35- pentaazaheptacyclo$B28.2.1.13,6. 18,11.014,27.015,20.021,26]pentariconta-1,3,5,7,9,11(35),12,14( 27),15(20),16,18,21(26),22,24,28,30(33,31-heptadecaene (3), are discussed. These compounds, which contain extended (pi) -systems, possess strong, low-energy, Q-like absorption bands in the 650-900 nm spectral region, making them of possible interest in photodynamic applications. Time-resolved absorption and emission laser studies have

Jonathan L. Sessler; Gregory Hemmi; Bhaskar G. Maiya; Anthony Harriman; Millard M. Judy; Richard L. Boriak; James Lester Matthews; Benjamin Ehrenberg; Zvi Malik; Yeshayahu Nitzan; Angelika C. Rueck

1991-01-01

82

Deriving bedform phase diagrams  

NSDL National Science Digital Library

Students prepare for this activity by working with a unidirectional flume with a sand bed. We adjust water depth, flow velocity, and channel slope to achieve a range of bed states, in an effort for them to understand the controls on bedforms. This portion of the activity could be done in lecture or via another exercise that makes use of digital video of actual experiments. The activity itself is a jigsaw: students form groups of three, each group responsible for plotting depth vs. velocity plots of bedform state for a single sand grain size range (0.10-0.14 mm, 0.5-0.64 mm, and 1.3-1.8 mm). These data are provided to them as Excel files and the data were directly 'stolen' from the original depth vs. velocity plots in Middleton and Southard (1984), Mechanics of Sediment Movement, SEPM Short Course Number 3. Datathief software (available free on the web) was used to steal the data. The data are arranged in columns: depth, velocity, and bedform type. Students must plot each of the different bedform types with a different symbol, then they have to define field boundaries. It is critical that they have never seen the original plots in their textbook. The goal is for them to derive them on their own, not to regurgitate what is in their textbook or elsewhere. After they complete their plots for each grain size range, the groups re-arrange themselves into groups of three with one representative from each of the grain size groups. They then must try to evaluate the effects of changing grain size on bedform state. Finally, after completing the exercise, the bedform analysis is linked to the cross stratification that is produced under conditions of high sediment fallout rates and the given bed state. The activity gives students practice working with realistic datasets, exposure to the role of physical modeling in sedimentary geology, and a chance to plot and interpret real data. Furthermore, it really solidifies the link between cross stratification and its dynamic interpretation from the rock record.

Hickson, Thomas

83

Phosphazene Based Additives for Improvement of Safety and Battery Lifetimes in Lithium-Ion Batteries  

Microsoft Academic Search

There need to be significant improvements made in lithium-ion battery technology, principally in the areas of safety and useful lifetimes to truly enable widespread adoption of large format batteries for the electrification of the light transportation fleet. In order to effect the transition to lithium ion technology in a timely fashion, one promising next step is through improvements to the

Mason K Harrup; Kevin L Gering; Harry W Rollins; Sergiy V Sazhin; Michael T Benson; David K Jamison; Christopher J Michelbacher

2011-01-01

84

Phosphazene-bound Rose Bengal: A novel photosensitizer for singlet oxygen generation  

Microsoft Academic Search

In this paper we report the synthesis and the characterization of cyclo- and polyphosphazenes supporting Rose Bengal. These substrates are suitable for the photosensitized generation of singlet oxygen, both in homogeneous and in heterogeneous phase. The efficiency of1O2 production has been measured in homogeneous solution using, as photosensitizer, the cyclophosphazene-bound Rose Bengal and considering, as testing reaction, the oxidation of

Giacomo Facchin; Francesco Minto; Mario Gleria; Roberta Bertani; Pietro Bortolus

1991-01-01

85

Key Derivation and Randomness Extraction  

Microsoft Academic Search

Key derivation refers to the process by which an agreed upon large random number, often named master secret, is used to derive keys to encrypt and authenticate data. Practitioners and standard- ization bodies have usually used the random oracle model to get key material from a Die-Hellman key exchange. However, proofs in the standard model require randomness extractors to formally

Olivier Chevassut; Pierre-Alain Fouque; Pierrick Gaudry; David Pointcheval

2005-01-01

86

21 CFR 184.1685 - Rennet (animal-derived) and chymosin preparation (fermentation-derived).  

Code of Federal Regulations, 2010 CFR

...animal-derived) and chymosin preparation (fermentation-derived). 184.1685 Section...animal-derived) and chymosin preparation (fermentation-derived). (a)(1...4.23.4). It is derived, via fermentation, from a nonpathogenic and...

2010-01-01

87

21 CFR 184.1685 - Rennet (animal-derived) and chymosin preparation (fermentation-derived).  

Code of Federal Regulations, 2010 CFR

...animal-derived) and chymosin preparation (fermentation-derived). 184.1685 Section...animal-derived) and chymosin preparation (fermentation-derived). (a)(1...4.23.4). It is derived, via fermentation, from a nonpathogenic and...

2009-04-01

88

MCR synthesis of praziquantel derivatives.  

PubMed

Schistosomiasis, a high volume neglected tropical disease affecting more than 200 million people worldwide, can only be effectively treated by the tetrahydroisoquinoline drug praziquantel (PZQ). Herein, we describe an efficient approach to access PZQ derivatives by the Ugi 4-component reaction followed by the Pictet-Spengler reaction in a two-step, one-pot procedure. 30 novel PZQ derivatives are described based on the Ugi 4-component reaction and an X-ray structure of a novel derivative revealing different conformation compared with PZQ is discussed. Several analogues comparable in activity to the drug PZQ have been identified based on an in vitro Schistosoma mansoni worm viability assay. PMID:22151001

Liu, Haixia; William, Samia; Herdtweck, Eberhardt; Botros, Sanaa; Dömling, Alexander

2012-01-30

89

Complex higher order derivative theories  

SciTech Connect

In this work is considered a complex scalar field theory with higher order derivative terms and interactions. A procedure is developed to quantize consistently this system avoiding the presence of negative norm states. In order to achieve this goal the original real scalar high order field theory is extended to a complex space attaching a complex total derivative to the theory. Next, by imposing reality conditions the complex theory is mapped to a pair of interacting real scalar field theories without the presence of higher derivative terms.

Margalli, Carlos A.; Vergara, J. David [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico 04510 DF (Mexico)

2012-08-24

90

Deriving Laws from Ordering Relations.  

National Technical Information Service (NTIS)

The effect of Richard T. Cox's contribution to probability theory was to generalize Boolean implication among logical statements to degrees of implication, which are manipulated using rules derived from consistency with Boolean algebra. These rules are kn...

K. H. Knuth

2004-01-01

91

CB2-Selective Cannabinoid Derivatives.  

National Technical Information Service (NTIS)

Cannabinoid derivatives that exhibit specificity for the CB(sub 2) cannabinoid receptor are provided. The analogues are tetrahydrocannabinols and hydroxyhexahydrocannabinols, and are useful for the treatment of pain, inflammation, and cancer.

B. R. Martin J. W. Huffman M. I. Damaj

2005-01-01

92

Topological Derivatives in Plane Elasticity  

Microsoft Academic Search

We present a method for construction of the topological derivatives in plane elasticity. It is assumed that a hole is created\\u000a in the subdomain of the elastic body which is filled out with isotropic material. The asymptotic analysis of elliptic boundary\\u000a value problems in singularly perturbed geometrical domains is used in order to derive the asymptotics of the shape functionals

Jan Sokolowski; Antoni Zochowski

2007-01-01

93

Citrinin derivatives from the marine-derived fungus Penicillium citrinum.  

PubMed

Three new citrinin derivatives, penicitrinols C, D, and E (1-3), along with two known compounds, citrinin (4) and decarboxydihydrocitrinone (5), were isolated from Penicillium citrinum. Their structures were determined by spectroscopic methods and X-ray diffraction analysis. Compounds 1 and 3 demonstrated weak cytotoxicity against the HL-60 cell line. PMID:21467687

Chen, Li; Liu, Wei; Hu, Xiao; Huang, Kai; Wu, Jiu-Lin; Zhang, Qi-Qing

2011-01-01

94

"Clickable" vitamin B12 derivative.  

PubMed

A "clickable" vitamin B12 derivative possessing the azide functionality at the 5'-position was synthesized by means of a two-step procedure on the gram scale. The reaction of cobalamin with mesyl chloride (MsCl) afforded the 5'-OMs derivative, which was subsequently transformed to the desired 5'-azide, the structure of which was confirmed using X-ray analysis. It proved to be reactive in the azide-alkyne 1,3-dipolar cycloaddition reaction to give substituted triazoles in high yields. A study of the reaction conditions and the scope of the process are reported. PMID:23325459

Chromi?ski, Miko?aj; Gryko, Dorota

2013-01-16

95

Magnetic cellulose-derivative structures  

DOEpatents

Structures to serve as selective magnetic sorbents are formed by dissolving a cellulose derivative such as cellulose triacetate in a solvent containing magnetic particles. The resulting solution is sprayed as a fine mist into a chamber containing a liquid coagulant such as n-hexane in which the cellulose derivative is insoluble but in which the coagulant is soluble or miscible. On contact with the coagulant, the mist forms free-flowing porous magnetic microspheric structures. These structures act as containers for the ion-selective or organic-selective sorption agent of choice. Some sorbtion agents can be incorporated during the manufacture of the structure.

Walsh, Myles A. (Falmouth, MA); Morris, Robert S. (Fairhaven, MA)

1986-09-16

96

Empirically derived injury prevention rules.  

PubMed Central

This study describes a set of empirically derived safety rules that if followed, would have prevented the occurrence of minor injuries. Epidemiologists have criticized behavioral interventions as increasing "safe" behavior but failing to demonstrate a decrease in injury. The present study documents retrospectively the link between safe behavior and injury. It demonstrates that these empirically derived rules are very similar to rules for the prevention of serious injury. The study also shows that these rules are not widely accepted and implemented by parents. Suggestions for future research in this area are advanced.

Peterson, L; Schick, B

1993-01-01

97

40 CFR 721.1820 - Bisphenol derivative.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Bisphenol derivative. 721.1820 Section 721...Chemical Substances § 721.1820 Bisphenol derivative. (a) Chemical substance...chemical substance identified generically as bisphenol derivative (PMN No....

2009-07-01

98

Quinuclidine Derivatives as Potential Antiparasitics  

Microsoft Academic Search

There is an urgent need for the development of new drugs for the treatment of tropical parasitic diseases such as Chagas' disease and leishmaniasis. One potential drug target in the organisms that cause these diseases is sterol biosynthesis. This paper describes the design and synthesis of quinuclidine derivatives as potential inhibitors of a key enzyme in sterol biosynthesis, squalene synthase

Simon B. Cammerer; Carmen Jimenez; Simon Jones; Ludovic Gros; Silvia Orenes Lorente; Carlos Rodrigues; Juliany C. F. Rodrigues; Aura Caldera; Luis Miguel Ruiz Perez; Wanderley da Souza; Marcel Kaiser; Reto Brun; Julio A. Urbina; Dolores Gonzalez Pacanowska; Ian H. Gilbert

2007-01-01

99

Shuttle derived unmanned launch vehicle  

Microsoft Academic Search

An unmanned launch vehicle derived using existing Space Transportation System (STS) components was studied. The vehicle incorporates a standard STS external tank and solid rocket boosters, a new payload module and a recoverable propulsion\\/avionics module housing the high cost avionics and propulsion systems. The main propulsion system is a cluster of three STS space shuttle main engines compatible with the

D. N. Buell; J. R. Tewell

1985-01-01

100

New hydrophobically modified carboxymethylcellulose derivatives  

Microsoft Academic Search

New hydrophobically substituted carboxymethylcellulose derivatives with different percentages of modification by hexadecylamine (from 0.9 to 6% per monomeric unit acid group) were obtained by amidation of the carboxyl group by different methods. The percentage of modification (% HDA) was controlled by conductimetric titration and quantitative 13C NMR spectra on cellulase hydrolyzed oligomers. The least degradation (checked by GPC measurements), was

D. Charpentier; G. Mocanu; A. Carpov; S. Chapelle; L. Merle; G. Müller

1997-01-01

101

Deriving Safety Requirements Using Scenarios  

Microsoft Academic Search

Elicitation of requirements for safety critical aero- engine control systems is dependent on the capture of core design intent and the systematic derivation of requirements addressing hazardous deviations from that intent. Deriva- tion of these requirements is inextricably linked to the safety assessment process. Conventional civil aerospace prac- tice (as advocated by guidelines such as ARP4754 and ARP4671) promotes the

Karen Allenby; Tim Kelly

2001-01-01

102

Microalgae derived biofuels and processes  

Microsoft Academic Search

only renewable biodiesel that can potentially completely displace liquid fuels derived from petroleum. The energy conversion reaction of microalgae can be classified into biochemical, thermochemical. Biochemical conversion can be further subdivided into alcoholic fermentation, anaerobic digestion and photobiological hydrogen production. Thermochemical conversion can be subdivided into gasification, pyrolysis and liquefaction. The productions of these processes include ethanol, methane, H2, Syngas,

Yibin Tian; Chunhu Li; Junjie Bian; Lijuan Feng

2011-01-01

103

Dimeric avermectin and milbemycin derivatives  

US Patent & Trademark Office Database

This invention provides for novel antiparasitic and pesticidal derivatives of avermectin and milbemycin compounds in which two avermectin or milbemycin members are linked together by a chemical linker. The resulting compounds may be used in veterinary compositions which are used in treating, controlling and preventing of endo- and ectoparasite infections and infestations in animals or for combating pests in plants or plant propagation material.

Meng; Charles Q. (Johns Creek, GA)

2013-04-23

104

Informational derivation of quantum theory  

SciTech Connect

We derive quantum theory from purely informational principles. Five elementary axioms - causality, perfect distinguishability, ideal compression, local distinguishability, and pure conditioning - define a broad class of theories of information processing that can be regarded as standard. One postulate - purification - singles out quantum theory within this class.

Chiribella, Giulio; D'Ariano, Giacomo Mauro; Perinotti, Paolo [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Ontario, N2L 2Y5 (Canada); QUIT Group, Dipartimento di Fisica ''A. Volta'' and INFN Sezione di Pavia, via Bassi 6, I-27100 Pavia (Italy)

2011-07-15

105

Lie Derivatives and Dynamical Systems  

Microsoft Academic Search

Applications of Lie derivatives in chaos synchronization and localization of periodic orbits are discussed. We present examples illustrating how one can construct a system that synchronizes with a given dynamical system, and how one can find a set that contains all periodic orbits of a dynamical system.

Ljupco Kocarev; Ulrich Parlitz; Bambi Hu

1998-01-01

106

Derived Categories and Lie Algebras  

Microsoft Academic Search

Let $\\\\md^b(A)$ be the derived category of a finite dimensional basic algebra $A$ with finite global dimension. We construct the Lie algebra arising from the 2-periodic version $\\\\mk_2(\\\\mp(A))$ of $\\\\mk^b(\\\\mp(A))$ in term of constructible functions on varieties attached to $\\\\mk_2(\\\\mp(A))$.

Jie Xiao; Fan Xu; Guanglian Zhang

2006-01-01

107

Anti-Leishmanial Lepidine Derivatives.  

National Technical Information Service (NTIS)

The subject 8-amino-6-methoxy lepidine derivatives have the formula: wherein, R represents an --alkylene (tertiary) amine, --alkylene-NH2, (N-alkylsubstituted piperadyl amino)-alkylene-, --alkylene-(tertiary) amine or -- alkylene-N-heterocyclic; R1, repre...

K. E. Kinnamon

1980-01-01

108

Alchemical derivatives of reaction energetics.  

PubMed

Based on molecular grand canonical ensemble density functional theory, we present a theoretical description of how reaction barriers and enthalpies change as atoms in the system are subjected to alchemical transformations, from one element into another. The change in the energy barrier for the umbrella inversion of ammonia is calculated along an alchemical path in which the molecule is transformed into water, and the change in the enthalpy of protonation for methane is calculated as the molecule is transformed into a neon atom via ammonia, water, and hydrogen fluoride. Alchemical derivatives are calculated analytically from the electrostatic potential in the unperturbed system, and compared to numerical derivatives calculated with finite difference interpolation of the pseudopotentials for the atoms being transformed. Good agreement is found between the analytical and numerical derivatives. Alchemical derivatives are also shown to be predictive for integer changes in atomic numbers for oxygen binding to a 79 atom palladium nanoparticle, illustrating their potential use in gradient-based optimization algorithms for the rational design of catalysts. PMID:20815557

Sheppard, Daniel; Henkelman, Graeme; von Lilienfeld, O Anatole

2010-08-28

109

Combustion of Waste Derived Fuel.  

National Technical Information Service (NTIS)

Over the past decade Warren Spring Laboratory has been involved in programs to investigate various aspects of the incineration of waste and the use of Refuse Derived Fuel (RDF). Investigations were carried out to assess the suitability of RDF for combusti...

B. J. Davis P. Clayton

1984-01-01

110

Revised derivation of Landau damping  

Microsoft Academic Search

We re-derive Landau's damping equation using an alternative method different from that of the original author. This alternative method results in a factor of two greater damping. This factor of two is a result of inconsistent assumptions by Landau about the nature of the singularity.

IGOR ALEXEFF; MARK RADER

1990-01-01

111

CRYSTALLINE ACETYL DERIVATIVES OF PEPSIN  

PubMed Central

Crystalline pepsin has been acetylated by the action of ketene in aqueous solution at pH 4.07–5.5. As acetylation proceeds the activity decreases, the decrease being more rapid at pH 5.0–5.5 than at 4.0–4.5. Three acetyl derivatives have been isolated from the reaction mixture and obtained in crystalline form. The crystal form of these derivatives is similar to that of pepsin. Fractionation and solubility determinations show that these preparations are not mixtures or solid solutions of the original pepsin with an inactive derivative. A compound which contains three or four acetyl groups and which has lost all of its original primary amino groups can be isolated after short acetylation. It has the same activity as the original pepsin. A second derivative containing six to eleven acetyl groups has also been isolated. It has about 60 per cent of the activity of the original pepsin. A third derivative having twenty to thirty acetyl groups and about 10 per cent of the activity of original pepsin can be isolated after prolonged acetylation. The 60 per cent active derivative on standing in strong acid solution loses some of its acetyl groups and at the same time regains the activity of the original pepsin. The compound obtained in this way is probably the same as the completely active three acetyl derivative obtained by mild acetylation. These results show that acetylation of three or four of the primary amino groups of pepsin causes no change in the specific activity of the enzyme but that the introduction of acetyl groups in other parts of the molecule results in a marked loss in activity. The solubilities, amino nitrogen content, acetyl content, isoelectric point, and the specific activity have been determined by a variety of methods and found to be different from the corresponding properties of crystalline pepsin. The pH-activity curves, acid and alkali inactivation, and titration curves were not significantly different from the same respective properties of pepsin.

Herriott, Roger M.; Northrop, John H.

1934-01-01

112

Columbus service vehicle and derivatives  

NASA Astrophysics Data System (ADS)

When Columbus phase B1 started in early 1985 the Service Vehicle (SV) was one of the four candidate elements to be developed by Europe in the frame of the U.S. Space Station program. The present paper will briefly summarize the main results achieved on the SV after phase B1 completion. It will also provide data on some SV derivatives which are currently under study, and particularly one resulting actually from an adaptation of this SV to a more European autonomous environment relying exclusively upon the use of Ariane and Hermes launchers: the so-called Ariane Transfer Vehicle (ATV). An other derivative is an answer to the manned space interventions issue, an intermediate concept betwen a manned SV and an astronaut with its ancilliary devices (e.g. Manned Maneuvering Unit).

Eymar, P.

1986-10-01

113

Plant-derived wildlife repellents  

US Patent & Trademark Office Database

Products from the plant species Nerium oleander and, Urginea maritima, are prepared and tested as wildlife repellents comparing them with digitalis products. Chemical compounds derived from these plants including oleandrin, oleandrigenin, scillirosidin, digitoxigenin and digoxigenin are shown to cause nausea and emesis at low doses in pigeons and to repel, mice, rats, gophers, meadow voles and mountain beavers. After ingestion these animals quickly learn to avoid targets treated with the plant-derived repellents. When the remembrance of a treated food or other target lasts for an extended period of time it can be termed an aversion conditioning agent. Such products can be used for the protection of other plants, seeds, buildings, structures, communication cables and animals exposed to wildlife.

Verbiscar; Anthony J. (Sierra Madre, CA)

1994-10-18

114

Photophysical characterization of fluorenone derivatives  

Microsoft Academic Search

The photophysics of several fluorenone derivatives was studied using fluorescence and laser-induced optoacoustic spectroscopy. Electron-donating substituents increase the energy of the key upper triplet state (T3) which, for the parent compound, is responsible for the increased intersystem crossing quantum yield in non-polar solvents. Electron-withdrawing substituents decrease the energy of T3, and an increase in the intersystem crossing rate constant is

R. S. Murphy; C. P. Moorlag; W. H. Green; C. Bohne

1997-01-01

115

Massive Higher Derivative Gravity Theories  

Microsoft Academic Search

In this thesis massive higher derivative gravity theories are analyzed in some detail. One-particle scattering amplitude between two covariantly conserved sources mediated by a graviton exchange is found at tree-level in $D$ dimensional (Anti)-de Sitter and flat spacetimes for the most general quadratic curvature theory augmented with the Pauli-Fierz mass term. From the amplitude expression, the Newtonian potential energies are

Ibrahim Gullu

2012-01-01

116

Berberine derivatives as antileishmanial drugs.  

PubMed Central

Berberine, a quaternary alkaloid, and several of its derivatives were tested for efficacy against Leishmania donovani and Leishmania braziliensis panamensis in golden hamsters. Tetrahydroberberine was less toxic and more potent than berberine against L. donovani but was not as potent as meglumine antimonate (Glucantime), a standard drug for the treatment of leishmaniasis. Only berberine and 8-cyanodihydroberberine showed significant activity (greater than 50% suppression of lesion size) against L. braziliensis panamensis.

Vennerstrom, J L; Lovelace, J K; Waits, V B; Hanson, W L; Klayman, D L

1990-01-01

117

Microglia-derived cytotoxic factors  

Microsoft Academic Search

The rarity of neoplasms in the adult mammalian retina has led us to hypothesize the presence or increased expression of `tumor-inhibitory molecules' in the mature differentiated retina. We have begun to investigate the source(s) of these molecules, and the following study describes the inhibitory activity of a soluble microglia-derived cytotoxic factor on the proliferation of C6 cells, a glial tumor

Armando A Rosales; Rouel S Roque

1997-01-01

118

Higher-derivative Quantum Cosmology  

Microsoft Academic Search

The quantum cosmology of a higher-derivative gravity theory arising from the heterotic string effective action is reviewed. A new type of Wheeler–DeWitt equation is obtained when the dilaton is coupled to the quadratic curvature terms. Techniques for solving the Wheeler–DeWitt equation with appropriate boundary conditions shall be described, and implications for semiclassical theories of inflationary cosmology will be outlined.

Simon Davis

2000-01-01

119

Resurgence of derived stimulus relations  

Microsoft Academic Search

Resurgence has been shown in human and nonhuman operant behavior, but not in derived rela- tional responses. The present study examined this issue. Twenty-three undergraduates were trained to make conditional discriminations in a three-choice matching-to-sample paradigm. The training resulted in three equivalence classes, each consisting of four arbitrarily configured visual stimuli. The same 12 stimuli were then reorganized, and the

KELLY G. WILSON; STEVEN C. HAYES

1996-01-01

120

SOME DERIVATIVES OF NEWTON'S METHOD  

Microsoft Academic Search

Every first-year calculus student learns Newton's method as part of a repertoire of numerical root-finding methods. We present two other numerical root-finding methods that we derive using Newton's method: a simplified Newton's method, and Halley's method. These two methods are not new, yet they seldom find their way into a first calculus course even though they would not be out

J. B. Thoo

2002-01-01

121

Some Derivatives of Newton's Method  

Microsoft Academic Search

Every rst-year calculus student learns Newton's method as part of a repertoire of numerical root-nding methods. We present two other numerical root-nding methods that we derive using Newton's method: a simplied Newton's method, and Halley's method. These two methods are not new, yet they seldom nd their way into a rst calculus course even though they would not be out

J. B. Thoo

2001-01-01

122

Deriving projective hyperspace from harmonic  

SciTech Connect

We derive actions for projective N=2 superspace ('hyperspace') from those for harmonic hyperspace, including that for non-Abelian Yang-Mills theory (a new result). The method uses Wick rotation of the sphere from complex conjugate coordinates to real, null ones, which can be treated as independent. The result can be considered 'holographic' in that the dimension of the internal (R symmetry) space is reduced from 2 to 1, by solving equations of motion or gauge conditions for dependence on the other coordinate. The auxiliary nature of the redundant dimension makes the hypergraph rules and evaluation almost identical.

Jain, Dharmesh; Siegel, Warren [C. N. Yang Institute for Theoretical Physics, State University of New York, Stony Brook, New York 11794-3840 (United States)

2009-08-15

123

Binder enhanced refuse derived fuel  

DOEpatents

A refuse derived fuel (RDF) pellet having about 11% or more particulate calcium hydroxide which is utilized in a combustionable mixture. The pellets are used in a particulate fuel bring a mixture of 10% or more, on a heat equivalent basis, of the RDF pellet which contains calcium hydroxide as a binder, with 50% or more, on a heat equivalent basis, of a sulphur containing coal. Combustion of the mixture is effective to produce an effluent gas from the combustion zone having a reduced SO.sub.2 and polycyclic aromatic hydrocarbon content of effluent gas from similar combustion materials not containing the calcium hydroxide.

Daugherty, Kenneth E. (Lewisville, TX); Venables, Barney J. (Denton, TX); Ohlsson, Oscar O. (Naperville, IL)

1996-01-01

124

Iron and iron derived radicals  

SciTech Connect

We have discussed some reactions of iron and iron-derived oxygen radicals that may be important in the production or treatment of tissue injury. Our conclusions challenge, to some extent, the usual lines of thought in this field of research. Insofar as they are born out by subsequent developments, the lessons they teach are two: Think fastexclamation Think smallexclamation In other words, think of the many fast reactions that can rapidly alter the production and fate of highly reactive intermediates, and when considering the impact of competitive reactions on such species, think how they affect the microenvironment (on the molecular scale) ''seen'' by each reactive molecule. 21 refs., 3 figs., 1 tab.

Borg, D.C.; Schaich, K.M.

1987-04-01

125

Diagrammatic derivation of Lovelock densities  

SciTech Connect

We discuss a method of calculating the various scalar densities encountered in Lovelock theory, which relies on diagrammatic, instead of algebraic manipulations. Taking advantage of the known symmetric and antisymmetric properties of the Riemann tensor that appears in the Lovelock densities, we map every quadratic or higher contraction into a corresponding permutation diagram. The derivation of the explicit form of each density is then reduced to identifying the distinct diagrams, from which we can also read off the overall combinatoric factors. The method is applied to the first Lovelock densities, of order two (Gauss-Bonnet term) and three.

Bogdanos, C. [Laboratoire de Physique Theorique, Universite de Paris-Sud 11, Batiment 210, 91405 Orsay CEDEX (France)

2009-05-15

126

Deriving projective hyperspace from harmonic  

NASA Astrophysics Data System (ADS)

We derive actions for projective N=2 superspace (“hyperspace”) from those for harmonic hyperspace, including that for non-Abelian Yang-Mills theory (a new result). The method uses Wick rotation of the sphere from complex conjugate coordinates to real, null ones, which can be treated as independent. The result can be considered “holographic” in that the dimension of the internal (R symmetry) space is reduced from 2 to 1, by solving equations of motion or gauge conditions for dependence on the other coordinate. The auxiliary nature of the redundant dimension makes the hypergraph rules and evaluation almost identical.

Jain, Dharmesh; Siegel, Warren

2009-08-01

127

Resurgence of derived stimulus relations.  

PubMed Central

Resurgence has been shown in human and nonhuman operant behavior, but not in derived relational responses. The present study examined this issue. Twenty-three undergraduates were trained to make conditional discriminations in a three-choice matching-to-sample paradigm. The training resulted in three equivalence classes, each consisting of four arbitrarily configured visual stimuli. The same 12 stimuli were then reorganized, and the conditional discrimination training was repeated such that three new classes were possible. In a subsequent test of derived relations, most subjects showed response patterns that were consistent with the altered conditional discriminations. Subjects were then exposed to conditional discrimination trials under extinction. Most subjects continued to respond consistently with the most recently reinforced conditional discrimination trials. During the next phase, subjects were exposed to symmetry and equivalence trials. Responses consistent with the most recent training produced feedback saying that the responses were incorrect, whereas other responses produced no feedback. Most subjects showed a resurgence of responding that was consistent with their earlier training. Finally, subjects were exposed to conditional discrimination trials carried out in extinction. Most subjects continued to show a resurgence of responding that was consistent with their early training.

Wilson, K G; Hayes, S C

1996-01-01

128

Fourth order spatial derivative gravity  

NASA Astrophysics Data System (ADS)

In this work, we study a modified theory of gravity that contains up to fourth order spatial derivatives as a model for the Ho?ava-Lifshitz gravity. The propagator is evaluated and, as a result, one extra pole is obtained, corresponding to a spin-2 nonrelativistic massless particle, an extra term which jeopardizes renormalizability, besides the unexpected general relativity unmodified propagator. Then unitarity is proved at the tree level, where the general relativity pole has been shown to have no dynamics, remaining only the 2 degrees of freedom of the new pole. Next, the nonrelativistic effective potential is determined from a scattering process of two identical massive gravitationally interacting bosons. In this limit, Newton’s potential is obtained, together with a Darwin-like term that comes from the extra nonpole term in the propagator. Regarding renormalizability, this extra term may be harmful by power counting, but it can be eliminated by adjusting the free parameters of the model. This adjustment is in accord with the detailed balance condition suggested in the literature and shows that the way in which extra spatial derivative terms are added is of fundamental importance.

Bemfica, F. S.; Gomes, M.

2011-10-01

129

40 CFR 721.10039 - Diethoxybenzenamine derivative, diazotized, coupled with aminonaphthalenesulfonic acid derivative...  

Code of Federal Regulations, 2013 CFR

...aminonaphthalenesulfonic acid derivative, ammonium salt (generic). 721.10039 Section 721...aminonaphthalenesulfonic acid derivative, ammonium salt (generic). (a) Chemical substance...aminonaphthalenesulfonic acid derivative, ammonium salt (PMN P-02-514) is subject to...

2013-07-01

130

Chromatography of coal derived products: general papers  

SciTech Connect

Twenty papers presented at the Symposium on Chromatography of Coal Derived Products are abstracted separately. These covered liquid column chromatography and gas chromatography/mass spectroscopy for separation and characterization of coal derived products.

Not Available

1981-01-01

131

Derivation of Equations for Variable Rainfall Infiltration.  

National Technical Information Service (NTIS)

Formulae were derived for prediction of ponding time and cumulative infiltration following ponding under a condition of variable and even intermittent rainfall. The derivations do not assume immediate saturation at the surface nor a piston displacement of...

H. J. Morel-Seytoux

1977-01-01

132

Treatment of Cancer Using Benzoic Acid Derivatives.  

National Technical Information Service (NTIS)

The present invention provides a method of treating cancer using benzoic acid derivatives, alone or in combination with standard treatments such as chemotherapy and radiotherapy. Also provided are methods of screening for benzoic derivatives based on thei...

D. Morais D. Rodriquez L. Liebes P. C. Brooks

2005-01-01

133

New, Water Soluble, Antineoplastic Derivatives of Taxol.  

National Technical Information Service (NTIS)

The invention is related to new, water soluble derivatives of taxol with antineoplastic activity. More particularly, the invention is related to 2'-0-acyl derivatives of taxol with improved water solubility while retaining antineoplasic property of the pa...

R. D. Haugwitz L. Zalkow J. Glinski M. Suffness H. M. Deutsch

1988-01-01

134

Evaluation of Derivatives of Gaussian Integrals.  

National Technical Information Service (NTIS)

We show that by a suitable change of variables, the derivatives of molecular integrals over Gaussian-type functions required for analytic energy derivatives can be evaluated with significantly less computational effort than current formulations. The reduc...

T. Helgaker P. R. Taylor

1992-01-01

135

Substituted N-Methyl Derivatives of Mitindomide.  

National Technical Information Service (NTIS)

The present invention relates to certain derivatives of diimidestatin (mitindomide) which is a photosynthetic addition product of benzene and maleimide. More particularly, the present invention relates to N-methyl derivatives of diimidestatin and methods ...

R. D. Haugwitz V. L. Narayanan L. H. Zalkow H. M. Deutsch

1987-01-01

136

Blunt-Cone Roll-Damping Derivative.  

National Technical Information Service (NTIS)

The roll-damping derivative is one of the many aerodynamic coefficients that influence the flight dynamics of a rolling missile. At present, the knowledge of this derivative is limited, especially for unfinned bodies of revolution in hypersonic flight. Th...

B. Quinn

1968-01-01

137

Thermodynamic Partial Derivatives and Experimentally Measurable Quantities.  

ERIC Educational Resources Information Center

|Proposed is a flow-chart and related formulas to obtain expressions for the derivatives of the old thermodynamic function in terms of new variables, the new function and its derivatives, and derivatives of the old function, involving only measurable quantities. (CW)|

Estevez, Gentil A.; And Others

1989-01-01

138

Derivative unfolding by spline techniques  

NASA Astrophysics Data System (ADS)

This paper presents some possible improvements to the derivative unfolding scheme employed in processing recoil proton data to obtain the neutron spectra. The scheme is based on representing the recoil proton spectrum by means of equally spaced cubic bell-splines. The finite spread in the detector response to monoenergetic protons is accounted for by folding the splines suitably. A code based on this formulation has been tested with trial spectra pertaining to standard neutron sources such as Pu-Be and has performed better in terms of resolution and of accuracy of the predicted peak positions. The current formulation is flexible for adding constraints using a priori information. This is demonstrated with respect to the suppression of spurious oscillations occurring near the high energy end of the spectra. This scheme is restricted to continuous spectra, however.

Subbaiah, K. V.; Natarajan, A.

1985-01-01

139

Optical nonlinearities of perylene derivatives  

NASA Astrophysics Data System (ADS)

Nonlinear optical properties of perylene derivatives were studied by femtosecond Z-scan technique. 3,4,9,10-Perylenetetracarboxylic dianhydride (PTCDA), 3,4,9,10-perylenetetracarboxylic diimide (PTCDI), and perylene-66 (dibenzthiophenoperylene-N,N'-dicyclohexylimide), were studied. Tetrahydrofuran was used as a solvent for perylene- 66. The solubility of PTCDA and PTCDI is very poor. Their colloidal solution was prepared by the irradiation of the third harmonics of a pulsed YAG laser to opaque suspension of PTCDA and PTCDI. Transparent colloidal solution was obtained within 50 minutes of UV irradiation. Colloidal solution of quinacridone was also studied. Two-photon absorption cross sections of these dyes were measured by open aperture Z-scan method using a femtosecond laser. The dependence of two-photon cross section on laser wavelength was measured in the wavelength range of 780-820 nm.

Sasaki, Yoshihiko; Takamo, Hiroyuki; Kasatani, Kazuo

2008-01-01

140

Anti-cancer quinazoline derivatives  

US Patent & Trademark Office Database

Quinazoline derivatives of formula: ##STR1## wherein R represents: (1) a straight or branched chain unsaturated hydrocarbon group, or (2) a straight or branched chain saturated or unsaturated hydrocarbon group which is substituted by at least one: heteroatom, the or each heteroatom being halogeno when R is a C.sub.1 hydrocarbon group; or saturated carbocyclic group; or group containing at least one heteroatom, the or each heteroatom being O, N or S when R contains a cyclic group; and n is 0 or an integer of 1-4; X or, when n is an integer of at least 2, each X independently, represents a halogeno, C.sub.1 -C.sub.4 alkyl, aryl or aralkyl group or a group including at least one heteroatom; and Y represents a group of formula: ##STR2## wherein m.gtoreq.1 (poly-L-glutamates); and the pharmaceutically acceptable salts and esters thereof, which are suitable as anti-cancer agents.

1984-05-08

141

Coumarin derivatives from Gerbera saxatilis.  

PubMed

Phytochemical investigation of Gerbera saxatilis (Astraceae) afforded three new coumarin derivatives 1- 3 and a known coumarin 4. Compounds 1 and 2 represent the first examples of the natural occurrence of the novel polycyclic pyrano[3-2c]coumarin carbon skeleton. The structures of compounds 1- 4 were characterized based on extensive spectroscopic analyses as well as comparison to the spectroscopic data reported. The structures of compounds 1 and 3 were further confirmed by X-ray data analyses. The cytotoxic activity of compounds 1- 4 was evaluated against selected cancer cell lines, including human leukemia cell (HL-60), human hepatoma cell (SMMC-7721), and human cervical carcinoma cell (HeLa) lines. PMID:20669089

Qiang, Yin; Chen, Yan-Jun; Li, Ya; Zhao, Jing; Gao, Kun

2010-07-28

142

Endothelium-derived endothelin-1  

PubMed Central

One year after the revelation by Dr. Furchgott in 1980 that the endothelium was obligatory for acetylcholine to relax isolated arteries, it was clearly shown that the endothelium could also promote contraction. In 1988, Dr. Yanagisawa’s group identified endothelin-1 (ET-1) as the first endothelium-derived contracting factor. The circulating levels of this short (21-amino acid) peptide were quickly determined in humans, and it was reported that, in most cardiovascular diseases, circulating levels of ET-1 were increased, and ET-1 was then tagged as “a bad guy.” The discovery of two receptor subtypes in 1990, ETA and ETB, permitted optimization of the first dual ET-1 receptor antagonist in 1993 by Dr. Clozel’s team, who entered clinical development with bosentan, which was offered to patients with pulmonary arterial hypertension in 2001. The revelation of Dr. Furchgott opened a Pandora’s box with ET-1 as one of the actors. In this brief review, we will discuss the physiological and pathophysiological role of endothelium-derived ET-1 focusing on the regulation of the vascular tone, and as much as possible in humans. The coronary bed will be used as a running example in this review because it is the most susceptible to endothelial dysfunction, but references to the cerebral and renal circulation will also be made. Many of the cardiovascular complications associated with aging and cardiovascular risk factors are initially attributable, at least in part, to endothelial dysfunction, particularly dysregulation of the vascular function associated with an imbalance in the close interdependence of nitric oxide and ET-1.

Thorin, Eric; Webb, David J.

2013-01-01

143

Basic cholane derivatives. XI: Comparison between acid and basic derivatives.  

PubMed

A series of hydroxycholan-24-amines was synthesized; the carboxyl group of starting unconjugated bile acids was transformed into a basic moiety [-NH2, -NHCH3, -N(CH3)2, or -NHCH2C6H5] at C-24. Solubilities, acidities, partition coefficients, and critical micellar concentrations were measured and compared with those of the corresponding bile acids. Because the steroid nucleus in the amines is the same as that in the bile acids, most of the physical-chemical properties of the two compound classes were similar. The amines were more soluble than the corresponding acids; solubilities depended mainly on the number of steroid hydroxyls and, to a lesser extent, on the side chain. Amines are strong bases in water, whereas unconjugated bile acids can be classified as weak acids. N-Benzylamino derivatives have higher log P (P is partition coefficient) values, as a consequence of the bulky hydrophobic substituent; the log P values were almost the same for the amines and the bile acids and depended on the steroid hydroxyls. Amines can self-aggregate at an acidic pH and form cationic micelles; the critical micellar concentrations of amines were of the same order of magnitude as those of bile acids. The introduction of a basic function in the side chain of the cholane moiety increased the antimicrobial activity toward most gram-positive strains. PMID:1403713

Fini, A; Fazio, G; Roda, A; Bellini, A M; Mencini, E; Guarneri, M

1992-07-01

144

Representations of partial derivatives in thermodynamics  

NSDL National Science Digital Library

One of the mathematical objects that students become familiar with in thermodynamics, often for the first time, is the partial derivative of a multivariable function. The symbolic representation of a partial derivative and related quantities present difficulties for students in both mathematical and physical contexts, most notably what it means to keep one or more variables fixed while taking the derivative with respect to a different variable. Material properties are themselves written as partial derivatives of various state functions (e.g., compressibility is a partial derivative of volume with respect to pressure). Research in courses at the University of Maine and Oregon State University yields findings related to the many ways that partial derivatives can be represented and interpreted in thermodynamics. Research has informed curricular development that elicits many of the difficulties using different representations (e.g., geometric) and different contexts (e.g., connecting partial derivatives to specific experiments).

Thompson, John R.; Manogue, Corinne A.; Roundy, David J.; Mountcastle, Donald B.

2012-05-15

145

Representations of partial derivatives in thermodynamics  

NASA Astrophysics Data System (ADS)

One of the mathematical objects that students become familiar with in thermodynamics, often for the first time, is the partial derivative of a multivariable function. The symbolic representation of a partial derivative and related quantities present difficulties for students in both mathematical and physical contexts, most notably what it means to keep one or more variables fixed while taking the derivative with respect to a different variable. Material properties are themselves written as partial derivatives of various state functions (e.g., compressibility is a partial derivative of volume with respect to pressure). Research in courses at the University of Maine and Oregon State University yields findings related to the many ways that partial derivatives can be represented and interpreted in thermodynamics. Research has informed curricular development that elicits many of the difficulties using different representations (e.g., geometric) and different contexts (e.g., connecting partial derivatives to specific experiments).

Thompson, John R.; Manogue, Corinne A.; Roundy, David J.; Mountcastle, Donald B.

2012-02-01

146

a Variational Derivation of P  

NASA Astrophysics Data System (ADS)

Multigroup P_{N} theory is a widely-used approximation to multigroup transport theory. However, there are aspects of multigroup P _{N} theory that are not satisfactory, particularly regarding boundary conditions at a boundary having a prescribed incident flux. Historically, P _{N} boundary conditions at such a boundary have been assumed to be in the form given by Marshak or Mark, although Federighi and Pomraning have considered other possibilities for the case of one energy group. In this work we introduce two new variational principles. The first principle, unambiguously leads from a steady-state, first order, slab geometry multigroup transport problem to a multigroup P_{N} problem. The variationally-derived P_{N } problem consists of the conventional multigroup P_{N} equations and variational boundary conditions. At a boundary with a prescribed incident flux, these conditions are new and consistitute a generalization of Pomraning's boundary conditions applied to each energy group. For a vacuum boundary, these conditions reduce the Federighi's boundary condition applied to each energy group. Therefore, we refer to these newly developed P _{N} boundary conditions as the Generalized Federighi-Pomraning (GFP) boundary conditions. The second variational principle introduced in this work leads from a steady-state, even-parity slab geometry, multigroup transport problem to a multigroup, second-order P _{N} problem. This problem consists of the multigroup second-order P_{N } equations and Marshak boundary conditions. We generalize the second-order variational procedure to the three-dimensional geometry and obtain the general geometry multigroup second-order P_{N} equations and the three-dimensional Marshak-like boundary conditions. We also show how the first-order variational principle can be used to derive rigorous boundary conditions for the even-order P_{N}~imations and that these P_{N} approximations can provide accurate numerical results. Finally, a numerical comparison of the Generalized Federighi-Pomraning, Mark, Marshak and (newly developed by Larsen and Pomraning) variational-asymptotic boundary conditions shows that outside the asymptotic limit in which the variational-asymptotic and GFP boundary conditions are always superior, different boundary conditions perform best in different physical situations.

Rulko, Robert Pawel

147

Massive Higher Derivative Gravity Theories  

NASA Astrophysics Data System (ADS)

In this thesis massive higher derivative gravity theories are analyzed in some detail. One-particle scattering amplitude between two covariantly conserved sources mediated by a graviton exchange is found at tree-level in D dimensional (Anti)-de Sitter and flat spacetimes for the most general quadratic curvature theory augmented with the Pauli-Fierz mass term. From the amplitude expression, the Newtonian potential energies are calculated for various cases. Also, from this amplitude and the propagator structure, a three dimensional unitary theory is identified. In the second part of the thesis, the found three dimensional unitary theory is studied in more detail from a canonical point of view. The general higher order action is written in terms of gauge-invariant functions both in flat and de Sitter backgrounds. The analysis is extended by adding static sources, spinning masses and the gravitational Chern-Simons term separately to the theory in the case of flat spacetime. For all cases the microscopic spectrum and the masses are found. In the discussion of curved spacetime, the masses are found in the relativistic and non-relativistic limits. In the Appendix, some useful calculations that are frequently used in the bulk of the thesis are given.

Gullu, Ibrahim

2012-01-01

148

Clinical status of benzoporphyrin derivative  

NASA Astrophysics Data System (ADS)

Benzoporphyrin derivative monoacid ring A (BPD) is currently in Phase II clinical trials for the treatment of cutaneous malignancies (basal cell carcinoma and cutaneous metastases) and psoriasis. Results to date suggest that this photosensitizer has potential in both of these areas. Recently, a clinical trial with BPD was initiated for the treatment of age related macular degeneration, a neovascular condition in the eye which leads to blindness. BPD is a lipophilic photosensitizer which is rapidly taken up by activated cells and the vascular endothelium of neovasculature. The PDT effects seen with BPD appear to be a combination of vascular occlusion and direct killing of target cells. Since many diseases involve either activated cells and/or neovasculature, PDT with photosensitizer with characteristics like those of BPD, has applications far wider than oncology. A new area of interest involving photosensitizers is that of immune modulation. A number of photosensitizers have been shown to effect immune modulation in animal models of immune dysfunction including autoimmunity (rheumatoid arthritis, lupus), cutaneous hypersensitivity and allografts. BPD and PHOTOFRINR have both been shown to be effective in ameliorating arthritic symptoms in a number of animal models. The mechanisms by which immune modulation is affected in these studies still remains to be resolved.

Levy, Julia G.; Chan, Agnes H.; Strong, H. Andrew

1996-01-01

149

Primary ear fibroblast derivation from mice.  

PubMed

Mouse embryonic fibroblasts (MEFs) are commonly utilized as a primary cell culture model and have several advantages over other types of ex vivo-derived cells. However, the successful generation of MEFs is time consuming and requires a certain level of mouse expertise to successfully complete. Thus, primary ear-derived fibroblasts offer an acceptable alternative to MEFs. Fibroblasts derived from the pinna of adult mice are easily attainable with minimal skill, proliferate rapidly, and are easy to manipulate. Likewise, because they are derived from adult mice, other organs can be concurrently harvested for the isolation of additional types of primary cells. Similar to MEFs, ear fibroblasts are an excellent ex vivo model system to study mechanisms associated with virus infection and produce a diverse array of inflammatory mediators, such as cytokines and interferon. Here, we describe a highly versatile and simple method for the derivation, maintenance, and viral challenge of primary ear-derived fibroblasts from mice. PMID:23824888

Moore, Chris B; Allen, Irving C

2013-01-01

150

Biosynthesis and biotechnological production of serotonin derivatives  

Microsoft Academic Search

Serotonin derivatives belong to a class of phenylpropanoid amides found at low levels in a wide range of plant species. Representative\\u000a serotonin derivatives include feruloylserotonin (FS) and 4-coumaroylserotonin (CS). Since the first identification of serotonin\\u000a derivatives in safflower seeds, their occurrence, biological significance, and pharmacological properties have been reported.\\u000a Recently, serotonin N-hydroxycinnamoyl transferase (SHT), which is responsible for the synthesis

Kiyoon Kang; Sangkyu Park; Young Soon Kim; Sungbeom Lee; Kyoungwhan Back

2009-01-01

151

Method for manufacturing neuraminic acid derivatives  

US Patent & Trademark Office Database

A method for manufacturing neuraminic acid derivatives is provided, also synthetic intermediates of the neuraminic acid derivatives and methods for their manufacture, and neuraminic acid derivatives having high purity. [Means for Solution] A synthetic intermediate compound represented by the formula (7) is provided: ##STR00001## [wherein R.sup.3 represents alkyl; R.sup.4 and R.sup.5 each represents H, alkyl, phenyl, or together represent tetramethylene, pentamethylene, oxo].

2013-06-04

152

Adsorption and desorption of cellulose derivatives  

Microsoft Academic Search

Cellulose derivatives, in particular carboxymethyl cellulose (CMC) are used in many (industrial) applications. The aim of this work is to obtain insight into the adsorption mechanism of cellulose derivatives on solid-liquid interfaces.In chapter 1<\\/strong> of this thesis we discuss some applications of cellulose derivatives. Application of CMC in pelleting of iron ore and in papermaking and the role of adsorption

C. W. Hoogendam

1998-01-01

153

Proceedings of refuse-derived fuel (RDF)  

SciTech Connect

This book contains proceedings of Refuse-Derived Fuel (RDF)-Quality. Standards and Processing. Topics covered include: An Overview of RDF Processing Systems: Current Status, Design Features, and Future Trends. The Impact of Recycling and Pre-Combustion Processing of Municipal Solid Waste on Fuel Properties and Steam Combustion. The Changing Role of Standards in the Marketing of RDF. Refuse Derived Fuel Quality Requirements for Firing in Utility, Industrial or Dedicated Boilers. Refuse-Derived Fuel Moisture Effects on Boiler Performance and Operability. Refuse Derived Fuels: Technology, Processing, Quality and Combustion Experiences.

Saltiel, C. (Florida Univ., Gainesville, FL (United States))

1991-01-01

154

Asymmetric syntheses of pipecolic acid and derivatives  

Microsoft Academic Search

Summary Results in the field of asymmetric synthesis of pipecolic acid derivatives are reviewed. Three sections describe the asymmetric syntheses of the title compounds (i) from the chiral pool (a-amino acids or carbohydrates) (ii) using a chiral auxiliary either derived from terpenes,a-amino acids, tartaric acid, an amine orß-amino alcohols (iii) by means of asymmetric catalysis.

François Couty

1999-01-01

155

Benzimidazole derivatives as potential anticancer agents.  

PubMed

Benzimidazole ring system is found in many bioactive heterocyclic compounds because of their diverse biological and clinical applications. Furthermore, benzimidazole derivatives are structural isosters of naturally occurring nucleotides, thus they can interact with biological macromolecules such as proteins, enzymes and receptors. This review discusses the benzimidazole derivatives which possess anticancer activity of medicinal efficacy. PMID:23190032

El Rashedy, Ahmed A; Aboul-Enein, Hassan Y

2013-03-01

156

Analysis of Blackbody Radiation with Derivative Spectroscopy.  

ERIC Educational Resources Information Center

Describes an undergraduate experiment which uses derivative spectroscopy to investigate the validity of the Planck function appearing in the blackbody radiation law. These measurements allow a critical examination of this function and also serve as an introduction to derivative spectroscopy techniques. (Author/HM)

Dusek, J.; And Others

1980-01-01

157

Smoothing Splines: Regression, Derivatives and Deconvolution  

Microsoft Academic Search

The statistical properties of a cubic smoothing spline and its derivative are analyzed. It is shown that unless unnatural boundary conditions hold, the integrated squared bias is dominated by local effects near the boundary. Similar effects are shown to occur in the regularized solution of a translation-kernel integral equation. These results are derived by developing a Fourier representation for a

John Rice; Murray Rosenblatt

1983-01-01

158

ADIFOR --- Generating Derivative Codes from Fortran Programs  

Microsoft Academic Search

. The numerical methods employed in the solution of many scientific computing problems require the computationof derivatives of a function f : Rn!Rm. Both the accuracy and the computationalrequirements of the derivative computationare usually of critical importance for the robustness and speed of the numerical solution. ADIFOR (Automatic DifferentiationIn FORtran) is a source transformation tool that accepts Fortran 77 code

1991-01-01

159

Derive Workshop Matrix Algebra and Linear Algebra.  

ERIC Educational Resources Information Center

This document presents the course content for a workshop that integrates the use of the computer algebra system Derive with topics in matrix and linear algebra. The first section is a guide to using Derive that provides information on how to write algebraic expressions, make graphs, save files, edit, define functions, differentiate expressions,…

Townsley Kulich, Lisa; Victor, Barbara

160

Derivative Markets' Impact on Colombian Monetary Policy  

Microsoft Academic Search

Derivatives are contingent claims that complete financial markets. Their use allow agents and firms to ameliorate the impact over con- sumption, production and investment given a change in relative prices induced by an active monetary policy. In this sense, derivatives gene- rate in some cases a loss in the effectiveness of the traditional monetary transmission channels in the short run,

Esteban Gómez; Diego Vásquez; Camilo Zea

161

Deriving Mode Invariants from SCR Specifications  

Microsoft Academic Search

This paper introduces a formal analysis method to derive modeclass invariants from software cost reduction (SCR) specifications. SCR specifications can be used to specify event-driven systems. Mode invariants in SCR specifications are used to capture safety features that must be ensured during software development. This new method derives mode invariants from well-defined, consistent SCR specifications by transforming an SCR mode

Zhenyi Jin

1996-01-01

162

Inter-relations among flutter derivatives  

Microsoft Academic Search

The interrelations and the approximate equivalences (or dependences) among the flutter derivatives of a low-speed airfoil are analytically described. Using the experimentally obtained flutter derivatives of three different bridge deck sections, the possible validity of the analogous relations for bridges is investigated and discussed.

R. H. Scanlan; N. P. Jones; L. Singh

1997-01-01

163

Comparative analysis of accounting treatments for derivatives  

Microsoft Academic Search

This paper provides educators with a classroom example or a self-study tutorial to teach Statement of Financial Accounting Standards No. 133 (FAS 133), Accounting for Derivative Instruments and Hedging Activities. The example can be used in courses such as intermediate or advanced accounting that discuss derivative instruments or investments topics or in a training program that focuses on implementing FAS

Angela L. J. Hwang

2002-01-01

164

Polymyxin derivatives: a patent evaluation (WO2012168820).  

PubMed

The patent application WO201268820 claims a new class of polymyxin derivatives with potent antibacterial activity, especially toward Gram-negative pathogens. Compared to parent polymyxin B (PMB), the new derivatives have more potent antibacterial activity, as well as reduced cytotoxicity against human renal cells. PMID:23806121

Wu, Haifan; Teng, Peng; Niu, Youhong; Li, Qi; Cai, Jianfeng

2013-06-28

165

Biological Analysis of Progressive Toxicity of Shale-Derived versus Petroleum-Derived Fuels in Rats.  

National Technical Information Service (NTIS)

The administration of petroleum-derived and shale-derived JP5 (Jet Propulsion No.5) to rats resulted in hepatocellular damage characterized by periportal fatty change, increase in binucleated cells, mitotic figures, and cellular necrosis. Elevated levels ...

W. J. Mehm C. L. Feser

1984-01-01

166

Aminoalkylcarbamyl Derivatives of Forskolin as Intermediates for the Synthesis of Useful Forskolin Derivatives.  

National Technical Information Service (NTIS)

The subject matter of the invention relates to aminoalkylcarbamates of forskolin and the uses of these compounds. Specifically, the aminoalkylcarbamates may be utilized as intermediates in the synthesis of forskolin derivatives. The final derivatives or a...

K. B. Seamon J. Robbins A. Laurenza

1990-01-01

167

Perhydroindan Derivatives. Ix. The Diels-Alder Reaction with 7-Methylindene Derivatives.  

National Technical Information Service (NTIS)

1,2-Dicarbomethyoxy-7-methylindene has been synthesized. The Diels-Alder reaction of this indene derivative with butadiene has been found to occur without migration of the carbon-carbon double bond to form the tetrahydrofluorene derivative. (Author)

H. O. House F. J. Sauter

1967-01-01

168

On Relations between the Derivative and the Two-Dimensional Directional Derivatives of a Quaternionic Function  

NASA Astrophysics Data System (ADS)

There is established the concept of two-dimensional directional derivative of a quaternionic function, which is related with the notion of Cullen regularity considered in detail by Gentili and Struppa. There are presented some relations between the notion of quaternionic derivative and two-dimensional directional derivatives.

Luna-Elizarrarás, M. E.; Macías-Cedeño, M. A.; Shapiro, M.

2007-09-01

169

ADIFOR: Fortran source translation for efficient derivatives  

SciTech Connect

The numerical methods employed in the solution of many scientific computing problems require the computation of derivatives of a function f: R{sup n} {yields} R{sup m}. Both the accuracy and the computational requirements of the derivative computation are usually of critical importance for the robustness and speed of the numerical method. ADIFOR (Automatic Differentiation In FORtran) is a source translation tool implemented using the data abstractions and program analysis capabilities of the ParaScope Parallel Programming Environment. ADIFOR accepts arbitrary Fortran-77 code defining the computation of a function and writes portable Fortran-77 code for the computation of its derivatives. In contrast to previous approaches, ADIFOR views automatic differentiation as a process of source translation that exploits computational context to reduce the cost of derivative computations. Experimental results show that ADIFOR can handle real-life codes, providing exact derivatives with a running time that is competitive with the standard divided-difference approximations of derivatives and which may perform orders of magnitude faster than divided-differences in cases. The computational scientist using ADIFOR is freed from worrying about the accurate and efficient computation of derivatives, even for complicated functions,'' and hence, is able to concentrate on the more important issues of algorithm design or system modeling. 35 refs.

Bischof, C.; Corliss, G.; Griewank, A.; Hovland, P. (Argonne National Lab., IL (United States)); Carle, A. (Rice Univ., Houston, TX (United States). Center for Research on Parallel Computation)

1992-01-01

170

Synthesis of Hemigossypol and its Derivatives  

PubMed Central

Hemigossypol (3), a sesquiterpene natural product, was previously isolated from Gossypium barbadense and was shown to display improved anti-fungal activity compared to gossypol (1), the disesquiterpene dimer of hemigossypol (3). Gossypol exhibits multiple biological activities. In order to study whether hemigossypol and it derivatives retain the various bioactivities of gossypol, we developed a short and convenient synthetic scheme to synthesize hemigossypol. This is the first de novo synthesis of this natural product. In addition derivatives of hemigossypol with various 2,5-alkyl substituents were synthesized. Modification of the synthetic scheme also afforded the natural product hemigossylic lactone (4) and its 2,5-substituted derivatives.

Wei, Jun; Vander Jagt, David L.; Royer, Robert E.; Deck, Lorraine M.

2012-01-01

171

Four new bibenzyl derivatives from Dendrobium candidum.  

PubMed

Four new bibenzyl derivatives, namely, dendrocandins F-I (1-4), were isolated from the stems of Dendrobium candidum. Their structures were elucidated by the analysis of spectroscopic data. Dendrocandins F and G represent the fourth and fifth example of bisbibenzyl derivates with a dibenzopyran ring between two units, respectively. Dendrocandin H represents the first example of a bibenzyl derivative formed by a bibenzyl and a 1,4-phenanthraquinone unit via a dibenzopyran ring. Compounds 1-4 were examined for antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. PMID:19721264

Li, Yan; Wang, Chun-Lan; Wang, Ya-Jun; Wang, Fang-Fei; Guo, Shun-Xing; Yang, Jun-Shan; Xiao, Pei-Gen

2009-09-01

172

[Research progress of chromanone derivatives from Calophyllum].  

PubMed

Calophyllum plants have great pharmaceutical value. Some species of this genus are used in folk medicine to treat and cure diseases, such as toothache, rheumatism, diarrhea, chronic ulcers, skin infections, and wounds. The genus is known to be rich in chromanone derivatives, and some of these compounds have antiviral, antifungal, antibacterial, cytotoxic, and other activities. In order to come to a more complete understanding of chromanone derivatives and gain new bioactive constituents from Calophyllum, chemical structures, pharmacological activities, and biogenesis of chromanone derivatives from Calophyllum have been discussed in this review. PMID:21842632

Wang, Huan; Wang, Yuehu; Li, Juan; Chen, Lijuan

2011-05-01

173

An endothelial cell-derived growth factor  

Microsoft Academic Search

Cell-free plasma-derived serum(PDS) isdeficient intheplatelet-derived growth factorand willnotsupportthegrowthof3T3 cells, fibroblasts, orsmoothmuscle cells .However,when PDS-containingmedium ispreincubatedwithendothelial cells, themedium becomesmodifiedsothatitwillsupportgrowth.The activity producedby theendothelial cellsresults from a polypeptideof10,000to30,000 daltonswhich hasseveralfeaturesthatdifferfrom thoseoftheplatelet-derived growthfactor, includingheatinstability and lackofadsorption toCM Sephadex. Growth ofnontransformed cellstrainsin culture requires one or more exogenous growth factors. The availabilityofthese polypeptides appears to determine the extent ofgrowth, and account, at leastin part, for

CORINNE GAJDUSEK; PAUL DICORLETO; RUSSELL ROSS; STEPHEN M. SCHWARTZ

1980-01-01

174

Derived Categories and Zero-Brane Stability  

SciTech Connect

We define a particular class of topological field theories associated to open strings and prove the resulting D-branes and open strings form the bounded derived category of coherent sheaves. This derivation is a variant of some ideas proposed recently by Douglas. We then argue that any 0-brane on any Calabi-Yau threefold must become unstable along some path in the Kahler moduli space. As a byproduct of this analysis we see how the derived category can be invariant under a birational transformation.

Lawrence, Albion

2001-07-25

175

Water Soluble Derivatives of Frederimacycin A.  

National Technical Information Service (NTIS)

The present invention is related generally to fredericamycin A. More particularly, the present invention is related to new, water soluble, biologically active derivatives of fredericamycin A and a process for making the same.

R. Misra

1986-01-01

176

Derivatives of the Stochastic Growth Rate  

PubMed Central

We consider stochastic matrix models for population driven by random environments which form a Markov chain. The top Lyapunov exponent a, which describes the long-term growth rate, depends smoothly on the demographic parameters (represented as matrix entries) and on the parameters that define the stochastic matrix of the driving Markov chain. The derivatives of a — the “stochastic elasticities” — with respect to changes in the demographic parameters were derived by Tuljapurkar (1990). These results are here extended to a formula for the derivatives with respect to changes in the Markov chain driving the environments. We supplement these formulas with rigorous bounds on computational estimation errors, and with rigorous derivations of both the new and the old formulas.

Steinsaltz, David; Tuljapurkar, Shripad; Horvitz, Carol

2011-01-01

177

32 CFR 2001.22 - Derivative classification.  

Code of Federal Regulations, 2013 CFR

...described in E.O. 12951, âRelease of Imagery Acquired by Space-Based National Intelligence Reconnaissance Systems,â the derivative...as prescribed by the Director of National Intelligence. (4) When determining the most...

2013-07-01

178

32 CFR 2001.22 - Derivative classification.  

Code of Federal Regulations, 2010 CFR

...described in E.O. 12951, âRelease of Imagery Acquired by Space-Based National Intelligence Reconnaissance Systems,â the derivative...as prescribed by the Director of National Intelligence. (4) When determining the most...

2010-07-01

179

Peanut-Derived Products Used as Ingredients  

Center for Food Safety and Applied Nutrition (CFSAN)

... work with their suppliers to ensure that all peanut-derived products used as ingredients or sold as food are not subject to an on-going product recall ... More results from www.fda.gov/food/guidanceregulation/retailfoodprotection

180

Cellulose Derivatives for Water Repellent Properties  

Technology Transfer Automated Retrieval System (TEKTRAN)

Synthesis and structural characterizations of nitro-benzyl cellulose, amino-benzyl cellulose and pentafluoro –benzyl cellulose were carried out. Cellulose derivatives were synthesized by etherification process in lithium chloride/N,N-dimethylacetamide homogeneous solution. Nitrobenzylation was effec...

181

Moment Systems Derived from Relativistic Kinetic Equations  

NASA Astrophysics Data System (ADS)

In this paper, we are interested in the derivation of macroscopic equations from kinetic ones using a moment method in a relativistic framework. More precisely, we establish the general form of moments that are compatible with the Lorentz invariance and derive a hierarchy of relativistic moment systems from a Boltzmann kinetic equation. The proof is based on the representation theory of Lie algebras. We then extend this derivation to the classical case and general families of moments that obey the Galilean invariance are also constructed. It is remarkable that the set of formal classical limits of the so-obtained relativistic moment systems is not identical to the set of classical moments quoted in Ref. 21 and one could use a new physically relevant criterion to derive suitable moment systems in the classical case. Finally, the ultra-relativistic limit is considered.

Bagland, Véronique; Degond, Pierre; Lemou, Mohammed

2006-11-01

182

Embryonic stem cell derivation from human embryos.  

PubMed

Human embryonic stem cells (hESCs) are self-renewing, pluripotent cells that serve as a valuable research tool and hold promise for use in regenerative medicine. Most hESC lines are derived from cryopreserved human embryos that were created during in vitro fertilization (IVF) and are in excess of clinical need. Embryos that are discarded during the IVF procedure are also a viable source of hESCs. hESCs can be derived from pre-blastocyst embryos and even from single blastomeres. However, hESC line derivation efficiency is greatest using embryos that have reached the blastocyst stage. This chapter describes a protocol for the derivation of pluripotent stem cell lines from human embryos. PMID:21822865

Lerou, Paul

2011-01-01

183

A New Derivation of the Logistic Distribution.  

National Technical Information Service (NTIS)

Logistic distribution is widely used in describing biological, engineering, industrial, and various other types of data. In this paper it is shown that this distribution is a special case of a compound generalized extreme value distribution which is deriv...

S. D. Dubey

1969-01-01

184

Analysis and the Derivation of Valid Objectives  

ERIC Educational Resources Information Center

|Author states that "to the extent that behavioral objectives are derived from an analysis of relatively broad objectives, they can serve as valid criteria which enable our students to avoid trivia." (Author)|

Tiemann, Philip W.

1973-01-01

185

Derivation of Relativistic Effects in Satellite Tracking.  

National Technical Information Service (NTIS)

Starting with the Schwarzschild solution to Einstein's field equations, the equations for relativistic corrections to satellite tracking are derived. Included are corrections for range from satellite to earth station, range from satellite to satellite, an...

L. R. Gibson

1983-01-01

186

Hydrothermal Syntheses of Some Derivatives of Tetraazatriphenylene  

Microsoft Academic Search

Some derivatives of tetraazatriphenylene can be synthesized readily by a hydrothermal synthetic method. Compared with the traditional technique, this method is effective and simple process, and much high yields of products with higher purity can be harvested.

Guangbo Che; Wenlian Li; Zhiguo Kong; Zisheng Su; Bei Chu; Bin Li; Zhiqiang Zhang; Zhizhi Hu; Haijun Chi

2006-01-01

187

12 CFR 163.172 - Financial derivatives.  

Code of Federal Regulations, 2013 CFR

12 Banks and Banking 1 2013-01-01 2013-01-01 false Financial derivatives. 163.172 Section 163.172 Banks and Banking COMPTROLLER OF THE CURRENCY...ASSOCIATIONS-OPERATIONS Financial Management Policies §...

2013-01-01

188

12 CFR 563.172 - Financial derivatives.  

Code of Federal Regulations, 2013 CFR

12 Banks and Banking 6 2013-01-01 2012-01-01 true Financial derivatives. 563.172 Section 563.172 Banks and Banking OFFICE OF THRIFT SUPERVISION...ASSOCIATIONS-OPERATIONS Financial Management Policies §...

2013-01-01

189

Diarylbenzopyran derivatives as cyclooxygenase-2 inhibitors  

US Patent & Trademark Office Database

The diarylbenzopyran derivatives represented by formula I, and the pharmaceutically acceptable salts thereof, are disclosed. The composition comprising the compound of formula I, or a pharmaceutically acceptable salt thereof, shows an excellent selective inhibition of cyclooxygenase-2. ##STR1##

2002-01-22

190

Inhibition of MXR transport by acridine derivatives  

US Patent & Trademark Office Database

This invention provides methods that are useful for inhibiting a MXR transporter in a cell overexpressing a MXR gene but not overexpressing a Pgp gene by contacting the cell with an acridine derivative. The invention also provides for a method of treating a mammal suffering from a cancer, which overexpressing a MXR gene but not overexpress a Pgp gene, by the co-administration of a chemotherapeutic and an acridine derivative.

2003-02-18

191

A New Derivation of Jeffery's Equation  

NASA Astrophysics Data System (ADS)

In this article, we present a modern derivation of Jeffery’s equation for the motion of a small rigid body immersed in a Navier Stokes flow, using methods of asymptotic analysis. While Jeffery’s result represents the leading order equations of a singularly perturbed flow problem involving ellipsoidal bodies, our formulation is for bodies of general shape and we also derive the equations of the next relevant order.

Junk, Michael; Illner, Reinhard

2007-12-01

192

Molluscicidal and trypanocidal activities of lapachol derivatives.  

PubMed

The activity of the potassium salt of lapachol against the snail Biomphalaria glabrata and its egg masses was tested. The obtained IC50 values (2.70 ppm and 1.43 ppm, respectively) are indicative of a strong activity. Lapachol derivatives were also assayed against infective trypomastigote blood forms of T. cruzi and the triacetoxy derivative of reduced lapachol showed relevant trypanocidal activity, killing 95.7% of the parasites at the concentration of 42 microg/mL. PMID:11270734

Santos, A F; Ferraz, P A; de Abreu, F C; Chiari, E; Goulart, M O; Sant'Ana, A E

2001-02-01

193

Antioxidant activity of chlorophylls and their derivatives  

Microsoft Academic Search

The antioxidant activity of six natural isolated chlorophyll derivatives and Cu-chlorophyllin was investigated by measuring their protective action against lipid oxidation. For this, the ?-carotene bleaching method and the stable radical 2,2-diphenyl-1-picryldrazyl (DPPH) scavenging assay were employed. The results obtained by the ?-carotene bleaching method showed that all chlorophyll derivatives presented a dose-dependent response. Pheophorbide b and pheophytin b were

Ursula M. Lanfer-Marquez; Rosa M. C. Barros; Patricia Sinnecker

2005-01-01

194

Duality completion of higher derivative corrections  

NASA Astrophysics Data System (ADS)

We present a new method for completing higher derivative corrections for theories that exhibit duality symmetries under reduction. This proposal is based on the observation that duality symmetry in the reduced theory highly constrains the form of the unreduced theory. We apply this idea to closed bosonic string theory and complete the Riemann squared term to simply derive the known full tree-level effective action to order ?'.

Godazgar, Hadi; Godazgar, Mahdi

2013-09-01

195

Defining DTG derivations to get semantic graphs  

Microsoft Academic Search

this paper is to find a formalism of theTAG family, where the derivation controller can beinterpreted as a semantic dependency graph, in thesense of Meaning-Text Theory (ZM67; M88).In a previous paper (CK98), we study thisinterpretation of the derivation tree (DT) in the caseof standard TAG. We prove that, in the general case,if the predicate-argument cooccurence principle

Marie-Hélène Candito; Sylvain Kahane

1998-01-01

196

Antimalarial Activities of Dermaseptin S4 Derivatives  

Microsoft Academic Search

The hemolytic antimicrobial peptide dermaseptin S4 was recently shown to exert antimalarial activity. In this study, we attempted to understand the underlying mechanism(s) and identify derivatives with improved antimalarial activity. A number of dermaseptin S4 derivatives inhibited parasite growth with a 50% inhibitory concentration (IC50) in the micromolar range. Among these, the substituted S4 analog K4K20-S4 was the most potent

MIRIAM KRUGLIAK; RINA FEDER; VADIM Y. ZOLOTAREV; LEONID GAIDUKOV; ARIE DAGAN; HAGAI GINSBURG; AMRAM MOR

2000-01-01

197

Leishmanicidal activity of new megazol derivatives.  

PubMed

A series of thirteen new megazol derivatives, designed exploring the molecular hybridization approach between megazol (3) and heterocombretastatins (2), was synthesized. These new compounds were tested for in vitro antiparasitic activity upon axenic amastigotes of Leishmania donovani. Biological results led us to identify a new potent megazol derivative (4g), which presents an IC(50) = 0.081microg/mL, more active tham the reference drug miltefosine (IC(50) = 0.131microg/mL). PMID:19689398

Riente, R R; Souza, V P; Carvalho, S A; Kaiser, M; Brun, R; da Silva, E F

2009-07-01

198

Preferential maternal derivation in inv dup(15)  

Microsoft Academic Search

Eight patients are reported with a de nov extra inverted duplicated chromosome 15. The abnormal chromosome was considered to be the same in all cases, but its precise delineation remained uncertain and was defined as either 15qter?15q12::15q12?15pter or 15pter?15q11::15q13?15pter. Analysis with various techniques of the satellite regions of the bisatellited chromosomes demonstrated maternal derivation in six and paternal derivation in

Paola Maraschio; Orsetta Zuffardi; Franca Bernardi; M. Bozzola; C. De Paoli; Christa Fonatsch; Sibylle D. Flatz; Loretta Ghersini; G. Gimelli; M. Loi; Renata Lorini; Diletta Peretti; Lisa Poloni; Daniela Tonetti; Roberta Vanni; G. Zamboni

1981-01-01

199

Thermal conductivity of pitch-derived fibres  

Microsoft Academic Search

The temperature variation of the thermal conductivity of pitch-derived carbon fibres measured from 3 to 300K is reported and discussed. The results are compared with those previously obtained on benzene-derived fibres (BDF) and with the room-temperature thermal conductivity of PAN-based carbon fibres, the GY70. The data confirm that the structure of pitch fibres is less perfect than that of BDF.

B. Nysten; L. Piraux; J.-P. Issi

1985-01-01

200

Stabilization of biomass-derived pyrolysis oils  

Microsoft Academic Search

BACKGROUND:Biomassistheonlyrenewablefeedstockcontainingcarbon,andthereforetheonlyalternativetofossil-derived crude oil derivatives. However, the main problems concerning the application of biomass for biofuels and bio-based chemicals are related to transport and handling, the limited scale of the conversion process and the competition with the food industry. Toovercome suchproblems,anintegralprocessing routefortheconversionof(non-feed)biomass(residues)totransportation fuels is proposed. It includes a pretreatment process by fast pyrolysis, followed by upgrading to produce a crude-oil-like product,

A. Oasmaa; J. Wildschut; A. R. Ardiyanti; R. H. Venderbosch; H. J. Heeres

2010-01-01

201

Myeloid derived suppressor cells in transplantation.  

PubMed

Myeloid derived suppressor cells (MDSC) are a heterogeneous population of hematopoietic derived cell precursors that can suppress immune responses in a variety of inflammatory settings. Here we review recent studies detailing expansion of phenotypically and functionally disparate MDSC. Findings related to MDSC accumulation, activation, and mechanisms utilized in immune suppression are presented. Further, we discuss recent reports that suggest MDSC are expanded during transplantation and that modulation of MDSC can participate in preventing graft rejection. PMID:21802931

Lees, Jason R; Azimzadeh, Agnes M; Bromberg, Jonathan S

2011-07-28

202

Derived versus full name brand extensions  

Microsoft Academic Search

Most brand extension studies follow the assumption that brand extensions use the full original parent brand name (e.g., Oral-B tooth brush may extend to Oral-B dental floss). However, some companies use derived brand names in their brand extension strategies (e.g. Nestea Iced Tea). This study explores the advantages and disadvantages of derived brand extensions compared to full name extensions. The

Sergio Olavarrieta; Eduardo Torres; Arturo Vásquez-Parraga; Cristóbal Barra

2009-01-01

203

Effects of alkyl substitution on the physical properties and gas transport behavior in selected poly(R-phenoxyphosphazenes)  

Microsoft Academic Search

A systematic preparation of alkyl substituted phenoxyphosphazene polymers was performed and their gas transport properties determined. In this study, phosphazenes substituted with 4-methylphenol, 4-ethylphenol, and 4-isopropylphenol are reported. An additional polymer substituted with 4-tert-butylphenoxy-1-ethanol also was synthesized in this work. Data derived for these materials, including chemical, thermal and gas transport characterization, were compared to previous reports discussing poly[bis-phenoxyphosphazene] and

Mark D. Ogden; Christopher J. Orme; Frederick F. Stewart

2011-01-01

204

Reactive Cyclophosphazenes Containing Oxazoline Groups: the Case of Hexakis(4-Oxazolinophenoxy)Cyclophosphazene  

Microsoft Academic Search

Hexakis(4-oxazolinophenoxy)cyclophosphazene, a multifunctional cyclophosphazene derivatives containing six pending oxazoline groups, was prepared by reacting hexachlorocyclo-phosphazene with 2-(4-hydroxyphenyl)-2-oxazoline. The resulting trimer was successively treated with carboxylic group-containing molecules (4-benzoyl-benzoic acid) and macromolecules (polyethylene terephthalate) to produce a novel photoinitiator and a polymer having higher molecular weight and improved mechanical properties, respectively.

Riccardo Po; Luisa Fiocca; Giorgio Giannotta; Emilio Lucchelli; Nicoletta Cardi; Francesco Minto; Luca Fambri; Mario Gleria

2001-01-01

205

Four new citrinin derivatives from a marine-derived Penicillium sp. fungal strain.  

PubMed

Four new citrinin derivatives, including two citrinin dimers and two citrinin monomer derivatives, were isolated and identified from a marine-derived fungal strain Penicillium sp. ML226 along with six known related compounds. Their structures were elucidated by spectroscopic and chemical methods. The new compounds showed modest cytotoxic activity against HepG-2 cell line and weak antimicrobial activity against Staphylococcus aureus. PMID:23681057

Wang, Mei Ling; Lu, Chun Hua; Xu, Qing Yan; Song, Si Yang; Hu, Zhi Yu; Zheng, Zhong Hui

2013-05-16

206

Novel benzimidazole derivatives as expected anticancer agents.  

PubMed

A series of 1-(1H-benzimidazol-2-yl)-3-(substituted)-2-propen-1-one and its 1-methyl analogues 2c-h were synthesized and cyclized with different reagents such as ethyl cyanoacetate, thiourea, hydroxylamine hydrochloride, guanidinium sulfate, methylhydrazine, phenylhydrazine and/or hydrogen peroxide in different reactions to produce pyridones 3a,b, pyrimidinethione 4a,b, isoxazole 5a,b, aminopyrimidine 6a,b, pyrazoline 7i-k and epoxy derivative 8, respectively. Acetohydrazide 10 reacted with formic acid, acetic anhydride, carbon disulfide and/or thiosemicarbazide to yield compounds 11-19. Also compound 21a,b was condensed with different monosaccharides to yield the corresponding N-glycoside Schiff's bases derivatives 22a-h, which upon treatment with acetic anhydride afforded 23a-h derivatives. The anticancer activity of some of the newly synthesized compounds was evaluated against HEPG2 (human liver carcinoma cell line) and PC12 (pheochromocytoma of the rat adrenal medulla) cells. Benzimidazole-2-isoxazole 5a derivative exhibited high potency against HEPG2 and PC12 cells. Benzimidazole chalcones 2c,e, benzimidazole mercaptoacetohydrazide 14 and benzimidazole thiosemicarbazide 15a,b derivatives gave high potency against PC12 cells. PMID:21796934

Nofal, Zienab M; Soliman, Elsyed A; Abd El-Karim, Somaia S; El Zahar, Magdy I; Srour, Aladdin M; Sethumadhavan, Shalini; Maher, Timothy J

207

Derivative expansion of the effective action  

SciTech Connect

This paper describes some methods for calculating derivative terms in the one loop effective action for a quantum field theory. The functional approach and background field method are first used to derive the general form of the one loop determinant. Then the determinant is expanded in powers of derivatives of the background fields. The form of this expansion is described for the simple case of an interacting scalar field, and then for the more complicated problem of a non-abelian gauge field. Finally, the expansion is applied to the task of calculating Higgs mass dependent effects in the Glashow-Weinberg-Salam model, and all terms which grow with the Higgs mass M/sub H/ are found in the one loop approximation. The result of this calculation is used to find the dependence of the gauge boson mass ratio rho on M/sub H/, and also to estimate the size of corrections to W and Z scattering theorems.

Cheyette, O.

1987-04-01

208

Photochemistry of riboflavin derivatives in methanolic solutions.  

PubMed

Light-induced degradation of the riboflavin derivatives is reported, including 5-deaza-riboflavin, iso-6,7-riboflavin, 3-methyl-tetra-acetyl-riboflavin (3MeTARF), and 3-benzyl-lumiflavin. The studied compounds undergo photolytic processes with considerable quantum yields in methanolic solutions (? ? 10(-3)-10(-4) mol einst(-1)). Photolysis in anaerobic conditions is more efficient than that in the presence of oxygen. Experiments show that triplet excited state of flavin molecules is involved in the reactions. The main photoproducts are the respective alloxazinic and isoalloxazinic derivatives of the substrates. 3MeTARF reveals higher photostability than riboflavin. The values of photodegradation quantum yields were estimated for the four studied derivatives. PMID:22217187

Insi?ska-Rak, Ma?gorzata; Golczak, Anna; Sikorski, Marek

2012-01-20

209

A thermodynamic derivation of the reciprocal relations.  

PubMed

Starting with the continuity and Smoluchowski equations, we write the mass flux for a system out of equilibrium in terms of the physicochemical potential ?(g). ?(g) is a coarse-grained analog of the chemical potential in the presence of forces that drive the system out of equilibrium. The expression for flux in terms of ?(g) allows for a macroscopic derivation of the Onsager reciprocal relations for the case of transport by diffusion and drift in single or multi-component systems, without recourse to microscopic fluctuations or equations of motion. Transport coefficients for any time reversal-invariant properties now are expressed in terms of only partial molar derivatives and mobilities (diffusion coefficients). The thermodynamic derivation cannot treat time reversal. PMID:23556731

Kocherginsky, N; Gruebele, M

2013-03-28

210

Understanding, Deriving, and Computing Buffer Capacity  

NASA Astrophysics Data System (ADS)

The concept of buffer capacity appears in varied disciplines, including bio-, geo-, analytical, and environmental chemistry, physiology, medicine, dentistry, and agriculture. Unfortunately, however, derivation and systematic calculation of buffer capacity is a topic that seems to be neglected in the undergraduate analytical chemistry curriculum. In this work, we give an account of the development of the buffer capacity concept and derive the buffer capacity contribution equations for buffer systems containing mono-, di-, and triprotic weak acids (and their conjugate bases) and aluminum(III), which undergoes hydrolysis. A brief review of pH is provided because pH is involved in applying buffer capacity to the real world. In addition, we discuss evaluation of the equations, numerical approximation of buffer capacity when an analytic solution is not derived, and the mathematical properties of the buffer capacity expressions.

Urbansky, Edward T.; Schock, Michael R.

2000-12-01

211

Immunosuppressive decalin derivatives from red yeast rice.  

PubMed

Five new decalin derivatives (1-5), together with two known compounds (6 and 7), were isolated from the ethyl acetate extract of red yeast rice. Their structures were elucidated by means of NMR and mass spectroscopic analyses. Monascusic lactone A (1) is the first reported naturally occurring decalin derivative possessing a spiro lactone at the C-1 position. The immunosuppressive effects of all these isolates (1-7) on human T cell proliferation were investigated, and all, especially monascusic acids B (2), C (3), D (4), and A (6) and heptaketide (7), suppressed human T cell proliferation in a dose-dependent manner from 10 to 100 ?M. This is the first report on the immunosuppressive activity of decalin derivatives. PMID:22394155

Zhu, Lin; Lu, Jing-Guang; Li, Ting; Zhu, Guo-Yuan; Han, Quan-Bin; Hsiao, Wen-Luan; Liu, Liang; Jiang, Zhi-Hong

2012-03-06

212

Catalytic hydrotreating of biomass-derived oils  

SciTech Connect

A variety of biomass-derived oils have been upgraded by catalytic hydrotreating in a 1-liter reactor system. High yields of high quality gasoline (C/sub 5/-225/sup 0/C boiling range) can be produced from biomass-derived oils, however, low space velocities (long residence times) are required. At high space velocities a low oxygen, highly aromatic crude oil is produced. Cracking and hydrogenation of the higher molecular weight components are the rate limiting steps in upgrading biomass-derived oils. Catalyst development should be directed at these reactions. The TR7 oil is superior to TR12 and both are much superior to pyrolysis oils as feedstocks for catalytic hydrotreating to produce hydrocarbon fuels. Pyrolysis oils can be upgraded by catalytic hydrotreating; however, a catalytic pretreatment step is required. Residual sodium catalyst needs to be removed from liquefaction products to prevent rapid catalyst fouling.

Baker, E.G.; Elliott, D.C.

1986-10-01

213

A Derivation of Modified Newtonian Dynamics  

NASA Astrophysics Data System (ADS)

Modified Newtonian Dynamics (MOND) is a possible solution for the missing mass problem in galactic dynamics; its predictions are in good agreement with observations in the limit of weak accelerations. However, MOND does not derive from a physical mechanism and does not make predictions on the transitional regime from Newtonian to modified dynamics; rather, empirical transition functions have to be constructed from the boundary conditions and comparisons with observations. I compare the formalism of classical MOND to the scaling law derived from a toy model of gravity based on virtual massive gravitons (the ``graviton picture'') which I proposed recently. I conclude that MOND naturally derives from the ``graviton picture'' at least for the case of non-relativistic, highly symmetric dynamical systems. This suggests that -- to first order -- the ``graviton picture'' indeed provides a valid candidate for the physical mechanism behind MOND and gravity on galactic scales in general.

Trippe, Sascha

2013-04-01

214

Derivation of wildlife values for mercury.  

PubMed

A procedure has been developed to estimate surface water concentrations of toxicants ("wildlife values") that will protect the viability of wildlife populations associated with aquatic resources. This procedure was designed primarily to protect piscivorous birds and mammals from compounds that bioaccumulate in fish and was used in the Great Lakes Water Quality Initiative (GLI) to calculate wildlife values (WV) for mercury, DDT/DDE, total polychlorinated biphenyls (PCBs), and 2,3,7,8-tetrachlorodibenzodioxin (TCDD). Published in 1995, and expressed as total mercury in unfiltered water, the final wildlife value (WVf) for mercury derived in the GLI was 1300 pg Hg/L. This value was selected as the wildlife criterion (WC) for mercury in the Great Lakes basin. A second WVf for mercury was derived in 1997 as part of a Congressionally mandated report on airborne mercury emissions. These calculations were based upon mercury speciation data that were largely unavailable when the GLI was developed. Important features of the WVf in the Report to Congress include its calculation on a dissolved methylmercury basis and a reliance on field data to estimate fish bioaccumulation factors. Calculated as methylmercury in filtered water, the WVf derived in the report is 50 pg Hg/L (equivalent to 54 pg MeHg/L). A comparison of WV in the GLI and the Report to Congress requires that average values be specified for mercury speciation in natural systems. Based on this information, the WVf given in the report corresponds to a value of 910 pg Hg/L, as total mercury in unfiltered water, or about 70% of the WVf derived in the GLI. In this article we describe the algorithm used to derive WV in the GLI and the Report to Congress and review its application to mercury. Scientific uncertainties in deriving WV, particularly as they apply to mercury, are critically examined. PMID:10596301

Nichols, J; Bradbury, S; Swartout, J

215

Transplants of blood-derived hematopoietic cells.  

PubMed

Increasing numbers of transplants, particularly autotransplants, are performed using blood-derived cells. Most subjects have leukemia but others have solid tumors or even genetic disorders. Despite this expanding data base, several important issues are unresolved. Can blood-derived cells reconstitute short-term hematopoiesis? Here, the answer is likely yes, although this is not yet proven. Studies using genetically marked cells should resolve this issue. Next, can blood-derived cells reconstitute long-term hematopoiesis? Here, the answer is unknown, but it would not be surprising were this not so. However, since most (if not all) high-dose chemotherapy and radiation treatments do not completely eradicate endogenous hematopoietic stem cells, reconstitution of long-term hematopoiesis from the graft may not be necessary for blood-derived grafts to be useful clinically. Another unresolved area is whether blood-derived grafts have a lower likelihood of tumor recurrence because of a lower probability of tumor contamination (qualitative or quantitative) or because of a different cellular composition of the graft. This issue is only answerable in controlled trials. Most data suggest that recurrence rate would not be higher than bone marrow-derived grafts. Whether it is lower is unknown. Analysis of this point is confounded by the fact that most (perhaps all) relapses that occur post-transplant using current conditioning schedules are explicable by residual leukemia in the recipient. Thus, tumor contamination of the graft is not presently an operationally important issue. There are some recent developments in this area. One is the use of umbilical cord blood cells to reconstitute hematopoiesis in a child with Fanconi anemia. Additional data are needed to evaluate this approach.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2180517

Gale, R P; Butturini, A

1990-01-01

216

Polyphenol derivatives - potential regulators of neutrophil activity  

PubMed Central

The study provides new information on the effect of natural polyphenols (derivatives of stilbene – resveratrol, pterostilbene, pinosylvin and piceatannol and derivatives of ferulic acid – curcumin, N-feruloylserotonin) on the activity of human neutrophils in influencing oxidative burst. All the polyphenols tested were found to reduce markedly the production of reactive oxygen species released by human neutrophils on extra-and intracellular levels as well as in cell free system. Moreover, pinosylvin, curcumin, N-feruloylserotonin and resveratrol decreased protein kinase C activity involved in neutrophil signalling and reactive oxygen species production. Our results suggest that due to their anti-neutrophil activity, the polyphenols tested might be attractive candidates in therapeutic development.

Perecko, Tomas; Nosal, Radomir; Harmatha, Juraj; Smidrkal, Jan; Jancinova, Viera

2012-01-01

217

Geometric derivation of the quantum speed limit  

SciTech Connect

The Mandelstam-Tamm and Margolus-Levitin inequalities play an important role in the study of quantum-mechanical processes in nature since they provide general limits on the speed of dynamical evolution. However, to date there has been only one derivation of the Margolus-Levitin inequality. In this paper, alternative geometric derivations for both inequalities are obtained from the statistical distance between quantum states. The inequalities are shown to hold for unitary evolution of pure and mixed states, and a counterexample to the inequalities is given for evolution described by completely positive trace-preserving maps. The counterexample shows that there is no quantum speed limit for nonunitary evolution.

Jones, Philip J.; Kok, Pieter [Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

2010-08-15

218

Caffeic acid derivatives from Eupatorium perfoliatum L.  

PubMed

From the ethyl acetate soluble fraction of a methanol/water extract of the herb Eupatorium perfoliatum L. (Asteraceae) six caffeic acid derivatives have been isolated and identified by 1D- and 2D-NMR spectroscopic data. Besides the common quinic acid derivatives 5-caffeoylquinic acid (chlorogenic acid), 3-caffeoylquinic acid (neochlorogenic acid) and 3,5-dicaffeoylquinic acid, three up to now unknown depsides of caffeic acid with glucaric acid have been isolated: 2,5-dicaffeoylglucaric acid, 3,4-dicaffeoylglucaric acid, and 2,4- or 3,5-dicaffeoylglucaric acid. PMID:19104484

Maas, Mareike; Petereit, Frank; Hensel, Andreas

2008-12-23

219

Elevation Derivatives for Mojave Desert Tortoise Habitat  

USGS Publications Warehouse

This report describes the methods used to derive various elevation-derivative grids that were inputted to the Mojave Desert Tortoise Habitat model (L. Gass and others, unpub. data). These grids, which capture information on surface roughness and topographic characteristics, are a subset of the environmental datasets evaluated for the tortoise habitat model. This habitat model is of major importance to the U.S. Fish and Wildlife Service, which is charged with management of this threatened population, including relocating displaced tortoises to areas identified as suitable habitat.

Wallace, Cynthia S. A.; Gass, Leila

2008-01-01

220

Iptycene-derived pyridazines and phthalazines.  

PubMed

The synthesis of new heterocyclic oligo(phenylene) analogues based on soluble, nonaggregating 1,2-diazines is reported. Improved palladium-catalyzed reductive coupling methods were developed to allow for the preparation of large quantities of iptycene-derived bipyridazines and biphthalazines, and the controlled synthesis of well-defined oligomers up to sexipyridazine. Crystallographic, spectroscopic, and computational evidence indicate that in these analogues, hindrance at the ortho position is relaxed relative to poly(phenylenes). The resulting building blocks are promising for incorporation in conjugated electronics materials, and as new iptycene-derived ligands for transition metals. PMID:18001104

Bouffard, Jean; Eaton, Robert F; Müller, Peter; Swager, Timothy M

2007-11-15

221

Inhibition of Noroviruses by Piperazine Derivatives  

PubMed Central

There is currently an unmet need for the development of small-molecule therapeutics for norovirus infection. The piperazine scaffold, a privileged structure embodied in many pharmacological agents, was used to synthesize an array of structurally-diverse derivatives which were screened for anti-norovius activity in a cell-based replicon system. The studies described herein demonstrate for the first time that functionalized piperazine derivatives possess anti-norovirus activity. Furthermore, these studies have led to the identification of two promising compounds (6a, 9l) that can be used as a launching pad for the optimization of potency, cytotoxicity, and drug-like characteristics.

Dou, Dengfeng; He, Guijia; Mandadapu, Sivakoteswara Rao; Aravapalli, Sridhar; Kim, Yunjeong; Chang, Kyeong-Ok; Groutas, William C.

2011-01-01

222

Classical solutions of higher-derivative theories  

NASA Astrophysics Data System (ADS)

We present exact classical solutions of the higher-derivative theory that describes the dynamics of the position modulus of a probe brane within a five-dimensional bulk. The solutions can be interpreted as static or time-dependent throats connecting two parallel branes. In the nonrelativistic limit the brane action is reduced to that of the Galileon theory. We derive exact solutions for the Galileon, which reproduce correctly the shape of the throats at large distances, but fail to do so for their central part. We also determine the parameter range for which the Vainshtein mechanism is reproduced within the brane theory.

Tetradis, Nikolaos

2013-10-01

223

Intercepting bacterial indole signaling with flustramine derivatives.  

PubMed

Indole signaling is one of the putative universal signaling networks in bacteria. We have investigated the use of desformylflustrabromine (dFBr) derivatives for the inhibition of biofilm formation through modulation of the indole-signaling network in Escherichia coli and Staphylococcus aureus . We have found dFBr derivatives that are 10-1000 times more active than indole itself, demonstrating that the flustramine family of indolic natural products represent a privileged scaffold for the design of molecules to control pathogenic bacterial behavior. PMID:22091927

Bunders, Cynthia A; Minvielle, Marine J; Worthington, Roberta J; Ortiz, Minoshka; Cavanagh, John; Melander, Christian

2011-11-22

224

Effects of guanidine derivatives on mitochondrial function  

PubMed Central

Long chain free fatty acids interfere with the inhibitory action of phenethylbiguanide and related compounds on mitochondrial respiration in vitro. This interference depends on binding of fatty acids to mitochondria and diminishes with decreasing chain length. Reversal of guanidine-derivative inhibition by fatty acids differs from that caused by dinitrophenol in that the effect of fatty acid is achieved without alteration in coupling or respiratory control. The binding of phenethylbiguanide to mitochondria is inhibited by both fatty acid and dinitrophenol. Serum albumin potentiates the inhibitory potency of guanidine derivatives, probably by removing endogenous mitochondrial free fatty acids.

Davidoff, Frank

1968-01-01

225

40 CFR 721.6097 - Phosphoric acid derivative (generic name).  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Phosphoric acid derivative (generic name...Chemical Substances § 721.6097 Phosphoric acid derivative (generic name...substance identified generically as a phosphoric acid derivative (PMN...

2009-07-01

226

21 CFR 173.135 - Catalase derived from Micrococcus lysodeikticus.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Catalase derived from Micrococcus lysodeikticus...Preparations and Microorganisms § 173.135 Catalase derived from Micrococcus lysodeikticus. Bacterial catalase derived from Micrococcus...

2010-01-01

227

21 CFR 173.135 - Catalase derived from Micrococcus lysodeikticus.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Catalase derived from Micrococcus lysodeikticus...Preparations and Microorganisms § 173.135 Catalase derived from Micrococcus lysodeikticus. Bacterial catalase derived from Micrococcus...

2009-04-01

228

Method of Introducing Hydroxyl Groups into Artemisinin and Its Derivatives.  

National Technical Information Service (NTIS)

The fungus Beauveria sulfurescens has been employed to introduce hydroxyl groups into artemisinin and derivatives of artemisinin, an antimalarial. Hydroxylated derivatives of artemisinin and derivatives of artemisinin produced thereby possess antimalarial...

H. Ziffer Y. Hu

1991-01-01

229

Recent developments of derivative spectrophotometry and their analytical applications.  

PubMed

Articles about the development of derivative spectrophotometric methods and analytical applications of derivative spectrophotometry (DS) published in the last nine years (since 1994) are reviewed. PMID:15984192

El-Sayed, Abdel-Aziz Y; El-Salem, Najeb A

2005-06-01

230

Fused thiophene derivatives as MEK inhibitors.  

PubMed

A number of novel fused thiophene derivatives have been prepared and identified as potent inhibitors of MEK. The SAR data of selected examples and the in vivo profiling of compound 13 h demonstrates the functional activity of this class of compounds in HT-29 PK/PD models. PMID:22119475

Laing, Victoria E; Brookings, Daniel C; Carbery, Rachel J; Simorte, Jose Gascon; Hutchings, Martin C; Langham, Barry J; Lowe, Martin A; Allen, Rodger A; Fetterman, Joanne R; Turner, James; Meier, Christoph; Kennedy, Jeff; Merriman, Mark

2011-11-06

231

Derivation of synchronous machine parameters from tests  

Microsoft Academic Search

This paper describes a test procedure for derivation of synchronous machine parameters. The tests can be conducted with ease and without hazard on generators in utility systems. Unlike textbook methods involving short circuit and slip tests which are inconvenient and hazardous, the proposed method involves simple procedures, which can be implemented in normal operation of the machine.

F. P. de Mello; J. R. Ribeiro

1977-01-01

232

Micropollutants emission from refuse derived fuel combustion.  

National Technical Information Service (NTIS)

In this work, fly ash and solid residues produced by an incinerator of Refuse Derived Fuel (RDF) have been analyzed for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and heavy metals. Furthermore, the content of that species in the f...

C. Di Palo M. Coronidi M. Zagaroli P. Zamora

1993-01-01

233

Synthesis and absorption spectra of thienylphenylpropenol derivatives  

Microsoft Academic Search

Fourteen thienylphenylpropenol derivatives containing substituents of varying electronic nature were synthesized. IR and NMR spectroscopy established that the a, ß-unsaturated alcohols obtained belong to the trans series. The electronic and PMR spectra of the alcohols in neutral and acidic solutions were studied. A correlation was found between the chemical shifts of the proton of the alcohol hydroxyl group and the

V. F. Lavrushin; R. I. Pogonina; N. S. Pivnenko; V. P. Izvekov

1970-01-01

234

Kriging and splines with derivative information  

Microsoft Academic Search

SUMMARY Spline fitting is a popular method of interpolating a real-valued function given its values at a set of points in W. Other linear constraints such as derivative information can also be incorporated as we show here. Spline fitting is well known to be a special case of kriging. Using the kriging framework we give a full description of the

K. V. MARDIA; J. T. KENT; C. R. GOODALL; J. A. LITTLE

1996-01-01

235

High speed point derivative microseismic detector  

DOEpatents

A high speed microseismic event detector constructed in accordance with the present invention uses a point derivative comb to quickly and accurately detect microseismic events. Compressional and shear waves impinging upon microseismic receiver stations disposed to collect waves are converted into digital data and analyzed using a point derivative comb including assurance of quiet periods prior to declaration of microseismic events. If a sufficient number of quiet periods have passed, the square of a two point derivative of the incoming digital signal is compared to a trip level threshold exceeding the determined noise level to declare a valid trial event. The squaring of the derivative emphasizes the differences between noise and signal, and the valid event is preferably declared when the trip threshold has been exceeded over a temporal comb width to realize a comb over a given time period. Once a trial event has been declared, the event is verified through a spatial comb, which applies the temporal event comb to additional stations. The detector according to the present invention quickly and accurately detects initial compressional waves indicative of a microseismic event which typically exceed the ambient cultural noise level by a small amount, and distinguishes the waves from subsequent larger amplitude shear waves. 9 figs.

Uhl, J.E.; Warpinski, N.R.; Whetten, E.B.

1998-06-30

236

Simple Derivation of the Lindblad Equation  

ERIC Educational Resources Information Center

|The Lindblad equation is an evolution equation for the density matrix in quantum theory. It is the general linear, Markovian, form which ensures that the density matrix is Hermitian, trace 1, positive and completely positive. Some elementary examples of the Lindblad equation are given. The derivation of the Lindblad equation presented here is…

Pearle, Philip

2012-01-01

237

Ion exchange membranes derived from sulfonated polyaramides  

Microsoft Academic Search

Homo- and both random and block copolyaramides of high molecular weights, with sulfonated moieties in the backbone, were obtained by low temperature polycondensation technique in a dipolar aprotic solvent (NMP) using (a) free aromatic diamines in the presence of pyridine as acid acceptor and (b) N,N?-bis-trimethylsilyl derivatives of the diamines without additional acid acceptor. The addition of low molecular weight

A Taeger; C Vogel; D Lehmann; D Jehnichen; H Komber; J Meier-Haack; N. A Ochoa; S. P Nunes; K.-V Peinemann

2003-01-01

238

Policy Search via the Signed Derivative  

Microsoft Academic Search

We consider policy search for reinforcement learn- ing: learning policy parameters, for some fixed policy class, that optimize performance of a system. In this paper, we propose a novel policy gradient method based on an approximation we call the Signed Derivative; the approximation is based on the intuition that it is often very easy to guess the direction in which

J. Zico Kolter; Andrew Y. Ng

239

Derivatives and the Graphs of Functions Microworld  

NSDL National Science Digital Library

The purpose of this Microworld is to experiment with some of the general applications of the derivative to the study of the behavior of functions. This includes their critical behavior, their local extrema, regions of monotonicity (increasing or decreasing), and their inflection points.

White, James

2004-11-01

240

Cellulose Derivatives for Water Repellent Properties  

Technology Transfer Automated Retrieval System (TEKTRAN)

In this poster presentation, we will discuss the synthesis and structural characterizations of nitro-benzyl cellulose (1), amino-benzyl cellulose (2) and pentafluoro –benzyl cellulose (3). All cellulose derivatives are synthesized by etherification process in lithium chloride/N,N-dimethylacetamide h...

241

Intelligent Use of Model-Derived Products  

NSDL National Science Digital Library

Many NWP output products must undergo internal processing in order to be readily displayed and used. This module examines how such products are developed, their strengths and weaknesses, and their application in the forecast process. The module focuses on three primary groups of model-derived products: postprocessed products, statistical guidance products, and model assessment tools.

Spangler, Tim

1999-08-31

242

Process for producing formaldehyde and derivatives thereof  

US Patent & Trademark Office Database

A process for formaldehyde production is disclosed comprising the steps of reacting methanol with formaldehyde to form methylal and then oxidizing the resulting methylal to obtain formaldehyde. Formaldehyde derivatives may also be produced. A dilute formaldehyde solution resulting from recovery of the product is recycled and used as feed material for the initial reaction step.

Masamoto; Junzo (Okayama, JP); Ohtake; Junzo (Okayama, JP); Kawamura; Mamoru (Saitama, JP)

1990-10-30

243

Deriving Petri Nets for Finite Transition Systems  

Microsoft Academic Search

This paper presents a novel method to derive a Petri Net from any specification model that can be mapped into a statebasedrepresentation with arcs labeled with symbols from an alphabet of events (a Transition System, TS). The method is based onthe theory of regions for Elementary Transition Systems (ETS). Previous work has shown that, for any ETS, there exists a

Jordi Cortadella; Michael Kishinevsky; Luciano Lavagno; Alexandre Yakovlev

1998-01-01

244

Radon-Nikodym Derivatives of Gaussian Measures  

Microsoft Academic Search

We give simple necessary and sufficient conditions on the mean and covariance for a Gaussian measure to be equivalent to Wiener measure. This was formerly an unsolved problem [26]. An unsolved problem is to obtain the Radom-Nikodym derivative $d\\\\mu\\/d\\\

L. A. Shepp

1966-01-01

245

Effects of artemisinin derivatives on malaria transmissibility  

Microsoft Academic Search

SummaryBackground On the western border of Thailand the efficacy of mefloquine in the treatment of falciparum malaria has declined while gametocyte carriage rates have increased, which suggests increased transmissibility of these resistant infections. We compared the following antimalarial drugs in relation to subsequent Plasmodium falciparum gametocyte carriage: mefloquine, halofantrine, quinine, and the artemisinin derivatives.Methods Between 1990 and 1995 we assessed

R. N Price; F Nosten; C Luxemburger; F. O ter Kuile; L Paiphun; T Chongsuphajaisiddhi; N. J White

1996-01-01

246

Morula-derived human embryonic stem cells  

Microsoft Academic Search

Human embryonic stem (ES) cells are known to derive from the inner cell mass of blastocyst. Although the embryos of other developmental stages have also been used as a source for ES cells in animal models, the feasibility of obtaining ES cell lines from human morula is not known, despite being an obvious source available through assisted reproduction and preimplantation

Nick Strelchenko; Oleg Verlinsky; Valeri Kukharenko; Yury Verlinsky

2004-01-01

247

Optimal design of derivatives in illiquid markets  

Microsoft Academic Search

The aim of this paper is to determine the optimal structure of derivatives written on an illiquid asset, such as a catastrophic or a weather event. This transaction involves two agents: a bank which wants to hedge its initial exposure towards this illiquid asset and an investor which may buy the contract. Both agents also have the opportunity to invest

Pauline Barrieu; Nicole El Karoui

2002-01-01

248

Alternative Derivations for the Poisson Integral Formula  

ERIC Educational Resources Information Center

|Poisson integral formula is revisited. The kernel in the Poisson integral formula can be derived in a series form through the direct BEM free of the concept of image point by using the null-field integral equation in conjunction with the degenerate kernels. The degenerate kernels for the closed-form Green's function and the series form of Poisson…

Chen, J. T.; Wu, C. S.

2006-01-01

249

Lie Algebras of Derivations and Resolvent Algebras  

NASA Astrophysics Data System (ADS)

This paper analyzes the action ? of a Lie algebra X by derivations on a C*-algebra {{A}} . This action satisfies an "almost inner" property which ensures affiliation of the generators of the derivations ? with {{A}} , and is expressed in terms of corresponding pseudo-resolvents. In particular, for an abelian Lie algebra X acting on a primitive C*-algebra {{A}} , it is shown that there is a central extension of X which determines algebraic relations of the underlying pseudo-resolvents. If the Lie action ? is ergodic, i. e. the only elements of {{A}} on which all the derivations in ? X vanish are multiples of the identity, then this extension is given by a (non-degenerate) symplectic form ? on X. Moreover, the algebra generated by the pseudo-resolvents coincides with the resolvent algebra based on the symplectic space ( X, ?). Thus the resolvent algebra of the canonical commutation relations, which was recently introduced in physically motivated analyses of quantum systems, appears also naturally in the representation theory of Lie algebras of derivations acting on C*-algebras.

Buchholz, Detlev; Grundling, Hendrik

2013-06-01

250

Adipose-derived stem cells and lattices  

US Patent & Trademark Office Database

The present invention provides adipose-derived stem cells (ADSCs), adipose-derived stem cell-enriched fractions (ADSC-EF) and adipose-derived lattices, alone and combined with the ADSCs of the invention. In one aspect, the present invention provides an ADSC substantially free of adipocytes and red blood cells and clonal populations of connective tissue stem cells. The ADSCs can be employed, alone or within biologically-compatible compositions, to generate differentiated tissues and structures, both in vivo and in vitro. Additionally, the ADSCs can be expanded and cultured to produce molecules such as hormones, and to provide conditioned culture media for supporting the growth and expansion of other cell populations. In another aspect, the present invention provides an adipose-derived lattice substantially devoid of cells, which includes extracellular matrix material from adipose tissue. The lattice can be used as a substrate to facilitate the growth and differentiation of cells, whether in vivo or in vitro, into anlagen or even mature tissues or structures.

Hedrick; Marc H. (Encino, CA); Katz; Adam J. (Charlottesville, VA); Llull; Ramon (Mallorca, Balearic Isles, ES); Futrell; J. William (Pittsburgh, PA); Benhaim; Prosper (Encino, CA); Lorenz; Hermann Peter (Belmont, CA); Zhu; Min (Los Angeles, CA)

2008-12-30

251

Managing Dairy Profit Risk Using Weather Derivatives  

Microsoft Academic Search

Weather conditions are a primary source of dairy production risk. Hot and humid weather induces heat stress, which reduces lactation. Heat abatement, such as ventilation, directly affects the temperature and humidity. Abatement can increase expected profit, but cannot eliminate the lost revenue caused by heat stress. Weather derivatives can reduce weather-induced profit risk and act as a substitute for abatement

Gang Chen; Matthew C. Roberts; Cameron S. Thraen

2006-01-01

252

Derived Transformation of Children's Pregambling Game Playing  

ERIC Educational Resources Information Center

|Contemporary behavior-analytic perspectives on gambling emphasize the impact of verbal relations, or derived relational responding and the transformation of stimulus functions, on the initiation and maintenance of gambling. Approached in this way, it is possible to undertake experimental analysis of the role of verbal/mediational variables in…

Dymond, Simon; Bateman, Helena; Dixon, Mark R.

2010-01-01

253

Pyrazole Derivatives of Three-Coordinated Boranes.  

National Technical Information Service (NTIS)

The application of the poly(1-pyrazolyl)borate ions, RnB(pz)4-n-(R = noncoordinating substituent, Hpz = pyrazole or C-substituted derivatives thereof, n=0, 1, 2), as polydentate ligands in coordination chemistry has resulted in a concentration of efforts ...

A. Meller J. Serwatowski K. Niedenzu L. Komorowski W. Maringgele

1990-01-01

254

Chemiluminescence of indole and its derivatives  

NASA Astrophysics Data System (ADS)

The results of studies on chemiluminescence of indole and its derivatives are critically analyzed. It is shown that chemical transformations of indoles lead, depending on the structure and experimental conditions, to various electronically excited products and emission of light. Many reactions considered are used as a basis for highly sensitive methods for detection of indoles in biology, medicine, ecology and forensics.

Vasil'ev, Rostislav F.; Trofimov, A. V.; Tsaplev, Yuri B.

2010-02-01

255

Representation of Empirically Derived Causal Relationships  

Microsoft Academic Search

The objective of this paper is to present a method for the computer representation of empiri­ cally derived causal relationships (CR's). This method draws on the theory of multivariate linear models and path analysis. The method is contrasted with the predicate calculus based methods used by most researchers in artificial intelligence. The representation presented here has been used to store

Robert L. Blum

1983-01-01

256

Derived, physically based distribution of flood probabilities  

Microsoft Academic Search

Traditional flood frequency analyses leave much uncertainty as to the magnitudes and return periods of large floods. An alternative, physically based stochastic approach to rainfall-runo ff modelling is discussed. A modified Soil Conservation Service runoff curve number method is used in Monte Carlo simulation to obtain a derived distribution of peak discharge. The potential of this approach in assessing the

I. MUZIK

1993-01-01

257

Model for the Derivation of Kinetic Theory.  

National Technical Information Service (NTIS)

A soluble model for the derivation of kinetic theory is discussed. It is shown that Bogoliubov's adiabatic assumption is not valid even to leading order in the kinetic regime. Furthermore, the adiabatic assumption gives rise to a singular behavior in the ...

G. V. Ramanathan G. Sandri

1969-01-01

258

Anticorrosion activity of some 2-mercaptobenzimidazole derivatives  

SciTech Connect

Corrosion-electrochemical behavior of steel 20 was studied in an acidic solution (1 M HCl), which contained inhibiting 2-mercaptobenzimidazole derivatives. Their effectiveness and nonselectivity are discussed. The results are interpreted from the viewpoint of a probable formation of macrocyclic chelate complexes and {pi}-bonded chelates, taking into account the resonance and induction factors of polar substituents.

Starchak, V.G.; Krasovskii, A.N.; Anishchenko, V.A.; Kosukhina, L.D. [Chernigov Technological Institute (Russian Federation)

1994-07-01

259

Derivation of the Ideal Gas Law  

ERIC Educational Resources Information Center

|Undergraduate and graduate physics and chemistry books usually state that combining the gas laws results in the ideal gas law. Leaving the derivation to the students implies that this should be a simple task, most likely a substitution. Boyle's law, Charles's law, and the Avogadro's principle are given under certain conditions; therefore, direct…

Laugier, Alexander; Garai, Jozsef

2007-01-01

260

Antimicrobial activity of resin acid derivatives  

Microsoft Academic Search

The wide potential of resin acids as bioactive agents gave rise to a growing effort in the search for new applications of the natural forms and their derivatives. In some of these compounds, the antimicrobial activity is associated to the presence in the molecules of functional groups such as the hydroxyl, aldehyde, and ketone or to their cis or trans

Sonia Savluchinske-Feio; Maria João Marcelo Curto; Bárbara Gigante; J. Carlos Roseiro

2006-01-01

261

Derivative luminescence spectra in lanthanide analysis  

SciTech Connect

This communication presents the results of derivative spectroscopic study of luminescence of complex compounds of europium and terbium. Solutions of complexes of europium with ethylenediaminetetraacetate, thenoyltrifluoroacetone, dibenzoylmethane, salicylate and 1,10-phenanthroline, and of terbium with phenyl ester of salicyclic acid and nalidixic acid were investigated.

Bel'tyukova, S.V.; Poluektov, N.S.; Tochidlovskaya, T.L.; Kucher, A.A.

1987-06-01

262

Determination of phosphorus using derivative neutron activation  

Microsoft Academic Search

For the determination of phosphorus in different matrices, the derivative neutron activation analysis is especially applicable to aqueous samples, since the conventional neutron activation analysis is not useful for the determination of phosphorus. Phosphorus when reacted with ammonium molybdate 4 hydrate and ammonium metavanadate forms molybdo vanado phosphoric acid. This complex is preconcentrated by extracting into methyl isobutyl ketone. The

Y. M. Scindia; A. G. C. Nair; A. V. R. Reddy; S. B. Manohar

2002-01-01

263

Root Coverage Technique with Enamel Matrix Derivative  

Microsoft Academic Search

Various periodontal plastic surgical techniques are employed in obtaining root coverage. Recently, the use of an enamel matrix derivative (EMD) has been reported in such treatment. We report 2 cases of root coverage surgery with a coronally positioned flap in combination with EMD (CPFEMD) and connective tissue graft in combination with EMD (CTGEMD). Case 1: The patient was a 25-year-old

Takafumi Moriyama; Shinya Matsumoto; Takemi Makiishi

2009-01-01

264

Coal fueled aero-derivative gas turbine  

Microsoft Academic Search

The direct use of coal as a gas turbine fuel offers the opportunity to burn coal in an environmentally sound manner at a competitive cost of energy. A development program is underway to verify the feasibility of using a coal water mixture to fuel an aero-derivative gas turbine. This paper presents the overall program approach, required gas turbine design modifications,

M. W. Horner; P. E. Sabla; S. G. Kimura

1988-01-01

265

Occupationally derived chemicals in breast milk  

Microsoft Academic Search

Exogenously derived chemicals have been widely reported in breast milk. Chemicals typically found in occupational exposures, including trace metals, solvents, and halogenated hydrocarbons, are reviewed, in terms of milk partition factors, potential infant exposures, and possible infant health effects. In addition to ingestion of a chemical from breast milk, an infant incurs a neonatal body burden of a chemical due

Mary S. Wolff

1983-01-01

266

Mathematical Relationships Derived from Biodiesel Fuels  

Microsoft Academic Search

The objective of this study was to estimate mathematical relationships derived from biodiesel fuels from various vegetable oils by non-catalytic supercritical methanol and ethanol method. The vegetable oils are all extremely viscous with viscosities ranging from 10 to 20 times greater than petroleum diesel fuel. The aim of the transesterification process is to lower the viscosity of the oil. Methyl

A. Demirbas

2007-01-01

267

Deriving Production Rules for Incremental View Maintenance  

Microsoft Academic Search

. It is widely recognized that production rules indatabase systems can be used to automatically maintain deriveddata such as views. However, writing a correct set ofrules for efficiently maintaining a given view can be a difficultand ad-hoc process. We provide a facility whereby a userdefines a view as an SQL select expression, from which thesystem automatically derives set-oriented production rulesthat

Stefano Ceri; Jennifer Widom

1991-01-01

268

Familial Follicular Cell-Derived Thyroid Carcinoma  

PubMed Central

Follicular cell-derived well-differentiated thyroid cancer, papillary (PTC) and follicular thyroid carcinomas comprise 95% of all thyroid malignancies. Familial follicular cell-derived well-differentiated thyroid cancers contribute 5% of cases. Such familial follicular cell-derived carcinomas or non-medullary thyroid carcinomas (NMTC) are divided into two clinical–pathological groups. The syndromic-associated group is composed of predominately non-thyroidal tumors and includes Pendred syndrome, Warner syndrome, Carney complex (CNC) type 1, PTEN-hamartoma tumor syndrome (PHTS; Cowden disease), and familial adenomatous polyposis (FAP)/Gardner syndrome. Other conditions with less established links to the development of follicular cell-derived tumors include ataxia–telangiectasia syndrome, McCune Albright syndrome, and Peutz–Jeghers syndrome. The final group encompasses syndromes typified by NMTC, as well as pure familial (f) PTC with or without oxyphilia, fPTC with multinodular goiter, and fPTC with papillary renal cell carcinoma. This heterogeneous group of diseases does not have the established genotype–phenotype correlations known as in the familial C-cell-derived tumors or medullary thyroid carcinomas (MTC). Clinicians should have the knowledge to identify the likelihood of a patient presenting with thyroid cancer having an additional underlying familial syndrome stemming from characteristics by examining morphological findings that would alert pathologists to recommend that patients undergo molecular genetic evaluation. This review discusses the clinical and pathological findings of patients with familial PTC, such as FAP, CNC, Werner syndrome, and Pendred syndrome, and the heterogeneous group of familial PTC.

Son, Eun Ju; Nose, Vania

2012-01-01

269

Asymptotics for General Multivariate Kernel Density Derivative Estimators  

Microsoft Academic Search

We investigate general kernel density derivative estimators, that is, kernel estimators of multivariate density derivative functions using general (or unconstrained) bandwidth matrix selectors. These density derivative estimators have been relatively less well researched than their density estimator analogues. A major obstacle for progress has been the intractability of the matrix analysis when treating higher order multivariate derivatives. With an alternative

Jose E. Chacon; T. Duon; M. P. Wand

2009-01-01

270

Fluid dynamic derivatives: Marine and wind engineering approaches  

Microsoft Academic Search

An alternative formulation, applied in marine and air craft fluid dynamics, of the traditional aerodynamic derivatives model, is presented. The relationship between the derivatives of the two models is derived, from which the exact interdependencies of the derivatives of the traditional model can be found. A forced motion model testing device, termed a planar motion mechanism (PMM), applicable for the

Andreas G. Jensen

1997-01-01

271

Canonical equilibrium distribution derived from Helmholtz potential  

NASA Astrophysics Data System (ADS)

Plastino and Curado [A. Plastino, E.M.F. Curado, Phys. Rev. E 72 (2005) 047103] recently determined the equilibrium probability distribution for the canonical ensemble using only phenomenological thermodynamical laws as an alternative to the entropy maximization procedure of Jaynes. In the current paper we present another alternative derivation of the canonical equilibrium probability distribution, which is based on the definition of the Helmholtz free energy (and its being constant at the equilibrium) and the assumption of the uniqueness of the equilibrium probability distribution. Noting that this particular derivation is applicable for all trace-form entropies, we also apply it to the Tsallis entropy, showing that the Tsallis entropy yields genuine inverse power laws.

Oikonomou, Thomas; Baris Bagci, G.; Tirnakli, Ugur

2012-12-01

272

Neuroprotective Properties of Chitosan and Its Derivatives  

PubMed Central

Neuronal cells are extremely vulnerable and have a limited capacity for self-repair in response to injury. For those reasons, there is obvious interest in limiting neuronal damage. Mechanisms and strategies used in order to protect against neuronal injury, apoptosis, dysfunction, and degeneration in the central nervous system are recognized as neuroprotection. Neuroprotection could be achieved through several classes of natural and synthetic neuroprotective agents. However, considering the side effects of synthetic neuroprotective agents, the search for natural neuroprotective agents has received great attention. Recently, an increasing number of studies have identified neuroprotective properties of chitosan and its derivatives; however, there are some significant challenges that must be overcome for the success of this approach. Hence, the objective of this review is to discuss neuroprotective properties of chitosan and its derivatives.

Pangestuti, Ratih; Kim, Se-Kwon

2010-01-01

273

Fractional derivatives of products of Airy functions  

NASA Astrophysics Data System (ADS)

Fractional derivatives of the products of Airy functions are investigated, and D[alpha]{Ai(x)×Bi(x)}, where Ai(x) and Bi(x) are the Airy functions of the first and second type, respectively. They turn out to be linear combinations of D[alpha]{Ai(x)} and D[alpha]{Gi(x)}, where Gi(x) is the Scorer function. It is also proved that the Wronskian of the system of half integrals {D-1/2Ai(x),D-1/2Gi(x)} and its Hilbert transform can be considered special functions in their own right since they are expressed in terms of and Ai(x)Bi(x), respectively. Various integral relations are established. Integral representations for D[alpha]{Ai(x-a)Ai(x+a)} and its Hilbert transform -HD[alpha]{Ai(x-a)Ai(x+a)} are derived.

Varlamov, Vladimir

2008-01-01

274

A probabilistic derivation of Stirling's formula  

NASA Astrophysics Data System (ADS)

Stirling's formula is one of the most frequently used results from asymptotics. It is used in probability and statistics, algorithm analysis and physics. In this thesis, we shall give a new probabilistic derivation of Stirling's formula. Our motivation comes from sampling randomly with replacement from a group of n distinct alternatives. Usually a repetition will occur before we obtain all n distinct alternatives consecutively. We shall show that Stirling's formula can be derived and interpreted as follows: as n approaches infinity the expected total number of distinct alternatives we must sample before all n are obtained consecutively is asymptotically equal to the expected number of attempts we make to obtain all n distinct alternatives consecutively times the expected number of distinct alternatives obtained per attempt.

Li, Hsin-Yun

1991-03-01

275

Liquiritigenin derivatives and their hepatotoprotective activity.  

PubMed

Liquiritigenin (7,4'-dihydroxyflavanone), isolated from the roots of Glycyrrhiza glabra, was derivatized to liquiritigenin 7, 4'-diacetate, liquiritigenin 4'-acetate, isoliquiritigenin, and liquiritigenin 7, 4'-dibenzoate. All these derivatives were evaluated for in vitro hepatoprotective activity against D-galactosamine-lipopolysaccharide(GalN/LPS) induced toxicity. In-vitro hepatotoxicity was manifested by a significant increase (P < 0.05) in liver toxicity biomarkers (SGPT, SGOT, ALKP, triglyceride, LPO, NO and LDH). The level of biomarkers in the treatment groups was significantly decreased (P < 0.05) when compared with the GalN/LPS group. The results revealed that isoliquiritigenin exhibited better hepatoprotective activity than liquiritigenin and its derivatives. PMID:20839627

Gaur, Rashmi; Kumar, Sunil; Trivedi, Priyanka; Bhakuni, Rajendra Singh; Bawankule, Dnyaneshwar Umrao; Pal, Anirban; Shanker, Karuna

2010-08-01

276

Mantle-derived Archaean monzodiorites and trachyandesites  

NASA Astrophysics Data System (ADS)

Geochemical data on monzodiorites and trachyandesites from the Rainy Lake area in Ontario which are strongly enriched in large-ion lithophile elements (LILE) are presented. It is concluded that they are derived by direct melting of the mantle at depths of less than 50 km in either anhydrous or hydrous conditions. Their rare earth element abundances and initial Nd-143/Nd-144 ratios suggest that their mantle sources were enriched in LILE shortly before melting. The monzodiorites-trachyandesites and their granodioritic derivatives may comprise up to 20 percent of the exposed igneous rocks in the Rainy Lake region and Vermilion District. If these rocks are as abundant in other Archaean terranes, a significant part of the early continental crust could have formed by direct melting of LILE-enriched mantle.

Shirey, S. B.; Hanson, G. N.

1984-07-01

277

A derivative standard for polarimeter calibration  

SciTech Connect

A long-standing problem in polarized electron physics is the lack of a traceable standard for calibrating electron spin polarimeters. While several polarimeters are absolutely calibrated to better than 2%, the typical instrument has an inherent accuracy no better than 10%. This variability among polarimeters makes it difficult to compare advances in polarized electron sources between laboratories. The authors have undertaken an effort to establish 100 nm thick molecular beam epitaxy grown GaAs(110) as a material which may be used as a derivative standard for calibrating systems possessing a solid state polarized electron source. The near-bandgap spin polarization of photoelectrons emitted from this material has been characterized for a variety of conditions and several laboratories which possess well calibrated polarimeters have measured the photoelectron polarization of cathodes cut from a common wafer. Despite instrumentation differences, the spread in the measurements is sufficiently small that this material may be used as a derivative calibration standard.

Mulhollan, G.; Clendenin, J.; Saez, P. [and others

1996-10-01

278

Polyphenol derivatives - potential regulators of neutrophil activity.  

PubMed

The study provides new information on the effect of natural polyphenols (derivatives of stilbene - resveratrol, pterostilbene, pinosylvin and piceatannol and derivatives of ferulic acid - curcumin, N-feruloylserotonin) on the activity of human neutrophils in influencing oxidative burst. All the polyphenols tested were found to reduce markedly the production of reactive oxygen species released by human neutrophils on extra-and intracellular levels as well as in cell free system. Moreover, pinosylvin, curcumin, N-feruloylserotonin and resveratrol decreased protein kinase C activity involved in neutrophil signalling and reactive oxygen species production. Our results suggest that due to their anti-neutrophil activity, the polyphenols tested might be attractive candidates in therapeutic development. PMID:23118589

Drábiková, Katarína; Pere?ko, Tomáš; Nosá?, Radomír; Harmatha, Juraj; Smidrkal, Jan; Jan?inová, Viera

2012-06-01

279

Vanadium and tungsten derivatives as antidiabetic agents  

Microsoft Academic Search

Tungstate is an oxyanion that has biological similarities to vanadate. In recent years, a number of studies have shown the\\u000a antidiabetic effects of oral tungstate in animal models of diabetes. However, because of the tissue accumulation and potential\\u000a toxicity derived from chronic administration of vanadium and tungsten compounds, the pharmacological use of vanadate or tungstate\\u000a in the treatment of diabetes

José L. Domingo

2002-01-01

280

Satellite Derived Tropical Ocean Surface Currents  

NSDL National Science Digital Library

Users can view imagery and read about tropical Pacific near-surface currents. The analysis is based on satellite altimeter- and scatterometer-derived sea level wind data. Materials presented here include monthly surface current maps, beginning with October 1992 and ending with the latest available satellite data (usually about one month delay). Links to related sites, a publications list, and a presentations list are also inlcuded.

281

Synthesis of ?-carboxyphosphinopeptides derived from norleucine  

Microsoft Academic Search

In the present study, we describe in detail the synthesis of a relatively rare class of phosphorus compounds, ?-carboxyphosphinopeptides.\\u000a We prepared several norleucine-derived ?-carboxyphosphinic pseudopeptides of the general formula Nle-?[PO(OH)]-Gly. These\\u000a compounds could have important applications as transition state-mimicking inhibitors for methionine or leucine aminopeptidases\\u000a or other enzymes. For the preparation of the key ?-carboxyphosphinate protected precursors, we investigated, compared

Jan Pícha; Miloš Bud?šínský; Pavel Fiedler; Miloslav Šanda; Ji?í Jirá?ek

2010-01-01

282

Lineage Tracing of Cardiac Explant Derived Cells  

Microsoft Academic Search

AimsCultured cardiac explants produce a heterogeneous population of cells including a distinctive population of refractile cells described here as small round cardiac explant derived cells (EDCs). The aim of this study was to explore the source, morphology and cardiogenic potential of EDCs.MethodsTransgenic MLC2v-Cre\\/ZEG, and actin-eGFP mice were used for lineage-tracing of EDCs in vitro and in vivo. C57B16 mice were

Lincoln T. Shenje; Loren J. Field; Catrin A. Pritchard; Christopher J. Guerin; Michael Rubart; Mark H. Soonpaa; Keng-Leong Ang; Manuel Galiñanes; Suzannah Rutherford

2008-01-01

283

Synthesis and biological activity of flavanone derivatives  

Microsoft Academic Search

A series of new flavanone derivatives of farrerol was synthesized by a convenient method. The in vitro anti-tumor activity of these compounds was evaluated against human Bel-7402, HL-60, BGC-823 and KB cell lines, the protein tyrosine kinase (PTK) inhibitor activity was also tested. Their cytoprotective activity was tested using hydrogen peroxide (H2O2)-induced injury in human umbilical vein endothelial cells. Their

Lei Shi; Xiu E Feng; Jing Rong Cui; Lian Hua Fang; Guan Hua Du; Qing Shan Li

2010-01-01

284

Biphenylmethane derivatives and pharmaceuticals containing the same  

US Patent & Trademark Office Database

This invention relates to a biphenylmethane derivative represented by the formula (1): ##STR1## wherein A represents a group ##STR2## in which R.sup.1, X, Y, Z and B are as defined in the Specification. The compounds have potent angiotensin II antagonist activity and anti-hypertensive effect. They have therapeutic utility for circulatory diseases such as hypertension, heart diseases and cerebral apoplexy.

Hirata; Terukage (Hiroshima, JP); Sakae; Nobuya (Hiroshima, JP); Tamura; Koichi (Hiroshima, JP); Okuhira; Masayasu (Hiroshima, JP); Amano; Hirotaka (Hiroshima, JP); Yokomoto; Masaharu (Hiroshima, JP); Nomiyama; Jun (Hiroshima, JP)

1997-08-05

285

Synthesis and pharmacological activity of diterpenylnaphthoquinone derivatives.  

PubMed

New diterpenylquinones, combining a diterpene diacid and a naphthoquinone, were prepared from junicedric acid and lapachol. The new derivatives were assessed as gastroprotective agents by the HCl-EtOH-induced gastric lesions model in mice as well as for basal cytotoxicity on the following human cell lines: Normal lung fibroblasts (MRC-5), gastric epithelial adenocarcinoma (AGS), and hepatocellular carcinoma (Hep G2). Several of the new compounds were significantly active as antiulcer agents and showed selective cytotoxicity against AGS cells. PMID:21996716

Pertino, Mariano Walter; Theoduloz, Cristina; Palenzuela, Jose Antonio; Afonso, Maria del Mar; Yesilada, Erdem; Monsalve, Francisco; González, Paulo; Droguett, Daniel; Schmeda-Hirschmann, Guillermo

2011-10-13

286

Hepatoprotective pyrrole derivatives of Lycium chinense fruits  

Microsoft Academic Search

As a part of our search for hepatoprotective compounds from Lycium chinense fruits, three new pyrrole derivatives (1–3) were isolated. These compounds and a related synthetic methylated compound (4) were evaluated for their biological activity and structure–activity relationship, and compounds 1 and 2 showed hepatoprotective effects comparable to silybin at the concentration of 0.1 ?M (64.4 and 65.8%, respectively).

Young-Won Chin; Song Won Lim; Seok-Ho Kim; Dong-Yun Shin; Young-Ger Suh; Yang-Bae Kim; Young Choong Kim; Jinwoong Kim

2003-01-01

287

Warped Phenomenology of Higher-Derivative Gravity  

Microsoft Academic Search

We examine the phenomenological implications at colliders for the existence of higher-derivative gravity terms as extensions to the Randall-Sundrum model. Such terms are expected to arise on rather general grounds, e.g. ,f rom string theory. In 5-d, if we demand that the theory be unitary and ghost free, these new contributions to the bulk action are uniquely of the Gauss-Bonnet

Thomas G. Rizzoa

288

Uncertainty estimates for derivatives and intercepts  

SciTech Connect

Straight line least squares fits of experimental data are widely used in the analysis of test results to provide derivatives and intercepts. A method for evaluating the uncertainty in these parameters is described. The method utilizes conventional least squares results and is applicable to experiments where the independent variable is controlled, but not necessarily free of error. A Monte Carlo verification of the method is given.

Clark, E.L.

1994-09-01

289

Crystal structures of proline-derived enamines  

PubMed Central

The isolation and structural characterization of both aldehyde- and ketone-derived proline enaminones are reported and discussed. Crystal structures of 10 proline enamines provide information on stereochemical aspects, i.e., double bond configuration and syn- vs. anti-positioning of the carboxylate relative to the enamine double bond. Furthermore, the obtained crystal structures are compared with the density functional theory-calculated structures of the ground and transition state and the postulated Seebach–Eschenmoser transition state.

Bock, Dominique Anna; Lehmann, Christian W.; List, Benjamin

2010-01-01

290

Milk Derived Peptides and Hypertension Reduction  

Microsoft Academic Search

This review deals with milk derived peptides related to hypertension reduction, especially those from Calpis sour milk fermented by a starter containing Lactobacillus helveticus and Saccaharomyces cerevisiae. The inhibitory activity of angiotensin-I-converting enzyme (ACE) in milk increased during fermentation with the sour milk starter. Inhibitors were purified and identified as Val–Pro–Pro and Ile–Pro–Pro. These amino acid sequences are found in

Toshiaki Takano

1998-01-01

291

On the Derivatives of Central Loops  

Microsoft Academic Search

The right(left) derivative, a?1,e? and e,a?1? isotopes of a C-loop are shown to be C-loops. Furthermore, for a central loop (L,F), it is shown thatF,Fa 1 ,Fa 1,eand ? F,F a 1,Fe,a 1 ? are systems of isotopic C-loops that obey a form of generalized dis- tributive law. Quasigroup isotopes (L, ?) and (L, ?) of a loop (L,?) and

T. G. Jaiyeo; J. O. Aden ´ õran

292

Chemically Derived, Ultrasmooth Graphene Nanoribbon Semiconductors  

Microsoft Academic Search

We developed a chemical route to produce graphene nanoribbons (GNR) with width below 10 nanometers, as well as single ribbons with varying widths along their lengths or containing lattice-defined graphene junctions for potential molecular electronics. The GNRs were solution-phase derived, stably suspended in solvents with noncovalent polymer functionalization, and exhibited ultrasmooth edges with possibly well-defined zigzag or armchair-edge structures. Electrical

Xiaolin Li; Xinran Wang; Li Zhang; Sangwon Lee; Hongjie Dai

2008-01-01

293

The derivation and interpretation of control coefficients.  

PubMed Central

1. Equations for control coefficients are derived by using a method that generates all the control coefficients for a system in a single procedure. This requires solving fewer simultaneous equations than an equivalent method based on 'control theorems'. 2. The interpretation of control coefficients is discussed: in particular, it is shown that these functions are unsatisfactory as measures of 'control' and are perhaps best used as a means of testing control theories (models).

Crabtree, B; Newsholme, E A

1987-01-01

294

New nonionic detergents derived from epoxidized oils  

Microsoft Academic Search

A new class of nonionic detergents derived from epoxidized oils having an oxirane oxygen content of 6–10% is discussed. Their\\u000a mol wt and micellar wt distributions, as studied in the ultracentrifuge, are presented and cited as partial explanations for\\u000a their unique properties as compared to conventional nonionic detergents such as ethoxylated alkyl phenols. Critical micelle\\u000a concentrations (CMC) determined by light

K. L. Johnson

1964-01-01

295

Carbon structures in silicon carbide derived carbon  

Microsoft Academic Search

Carbide derived carbon (CDC) produced by etching SiC in halogens has been investigated using transmission electron microscopy (TEM). Depending on experimental conditions, CDC may contain sp3- or sp2-bonded carbon phases. Amorphous carbon, poorly ordered turbostratic carbon with lattice spacing exceeding values of 0.35nm as well as highly ordered graphite were observed. sp3-Bonded structures consist of mainly lonsdaleite and cubic diamond

Sascha Welz; Michael J. McNallan; Yury Gogotsi

2006-01-01

296

Theoretical study of borazine and its derivatives  

Microsoft Academic Search

The density functional theory is used to study the geometries, electronic structures, and aromaticity of borazine and its fused ring derivatives. Some new evidences for the ionic nature of B–N bond are found. Geometry studies show that the B–N bond lengths are equal. The lone pair VSCCs of the N atoms are found. As shown, the B–N bonds are of

Wei Shen; Ming Li; Ying Li; Silei Wang

2007-01-01

297

New 23-spirocholestane derivatives from Ypsilandra thibetica.  

PubMed

Three new unusual 23-spirocholestane derivatives, ypsilanogenin (1), ypsilanogenin 3-O-?-D-glucopyranoside (2), and 4'-acetylypsilanogenin 3-O-?-D-glucopyranoside (3), were isolated from the whole plants of Ypsilandra thibetica. The structures of compounds 1-3 were deduced by spectroscopic and chemical methods, and the structure of 1 was further confirmed by a single-crystal diffraction analysis. All isolates were evaluated for their inhibitory activities against HIV-1. PMID:23818269

Xie, Bai-Bo; Chen, Chang-Xiang; Guo, Yong-Hui; Li, Yu-Ye; Liu, Ya-Juan; Ni, Wei; Yang, Liu-Meng; Gong, Ning-Bo; Zheng, Yong-Tang; Wang, Rui-Rui; Lü, Yang; Liu, Hai-Yang

2013-07-01

298

Stop-loss strategies and derivatives portfolios  

Microsoft Academic Search

We carry out a Monte-Carlo simulation of the long-term behaviour of a standard derivatives portfolio to analyse the performance of stop-loss strategies in terms of loss reductions. We observe that the more correlated the underlyings, the earlier the stop-loss activation for every acceptable level of losses. Switching from 0-correlation across underlyings to a very mild form of correlation significantly decreases

Patrick L. Leoni

2008-01-01

299

Inactivation of coliphages by chitosan derivatives  

Microsoft Academic Search

The effect of chitosan fragments with different degrees of polymerization and the chemical derivatives of chitosan differing\\u000a in the number of amino groups and total molecule charge on phages T2, T4, and T7 was studied. The interaction of chitosan\\u000a with bacteriophage particles inactivated them to the extent dependent on the chemical properties of chitosan and its concentration.\\u000a Phage T2 was

Z. M. Kochkina; N. A. Surgucheva; S. N. Chirkov

2000-01-01

300

On Farm Durum-Wheat Derived Products  

Microsoft Academic Search

The adoption of traditional durum-wheat cultivars is attributed not only to the specific adaptation of these cultivars, low-input cultural practices, and difficult growing conditions but also to the greater nutritional quality traits of derived end products such as color, flavor, protein content, and taste. In the cities the main factors underlying consumer perception and preference for at-home (or on-farm) processed

L. Zaibet; S. Rezgui; O. Bouicha; A. Daaloul

2007-01-01

301

Enhanced coset symmetries and higher derivative corrections  

SciTech Connect

After dimensional reduction to three dimensions, the lowest order effective actions for pure gravity, M theory, and the bosonic string admit an enhanced symmetry group. In this paper we initiate study of how this enhancement is affected by the inclusion of higher derivative terms. In particular we show that the coefficients of the scalar fields associated to the Cartan subalgebra are given by weights of the enhanced symmetry group.

Lambert, Neil; West, Peter [Department of Mathematics, King's College, The Strand London WC2R 2LS (United Kingdom)

2006-09-15

302

Cytotoxic rocaglamide derivatives from Aglaia duppereana.  

PubMed

Phytochemical investigation of Aglaia duppereana flowers led to the isolation of a new rocaglamide derivative and twelve known congeners. The structure of the new compound was unambiguously elucidated by spectroscopic techniques (1D- and 2D-NMR, HRESIMS). The isolated compounds exhibited a potent cytotoxic activity against mouse lymphoma (L5178Y) cells with EC50 values ranging from 5.1 to 54.8 nM. PMID:24066511

El-Neketi, Mona; Ebrahim, Weaam; Duong, Ngoc Tu; Gedara, Sahar; Badria, Farid; Saad, Hassan-Elrady A; Müller, Werner E G; Proksch, Peter

303

Thematic Indicators Derived from World News Reports  

Microsoft Academic Search

\\u000a A method for deriving statistical indicators from the Europe Media Monitor (EMM) is described. EMM monitors world news in\\u000a real time from the Internet and various News Agencies. The new method measures the intensity of news reporting for any country\\u000a concerning a particular theme. Two normalised indicators are defined for each theme (j) and for each country (c). The first

Clive Best; Erik Van Der Goot; Monica De Paola

2005-01-01

304

Nile Blue derivatives as lysosomotropic photosensitizers  

NASA Astrophysics Data System (ADS)

The benzophenoxazines, including several Nile blue analogues, are a unique group of dyes that localize selectively in animal tumors. Chemical modifications of Nile blue A can yield derivatives with high 1O2 quantum yields. These derivatives represent a group of potentially effective photosensitizers for selective phototherapy of malignant tumors. In vitro evaluation of these derivatives has indicated that those with high 1O2 yields are very effective in mediating the photocytotoxicity of tumor cells. This photodynamic effect is most likely mediated through the action of 1O2, since photoirradiation under D2O enhanced and under hypoxic conditions diminished the photocytotoxic action. The subcellular localization of these photosensitizers in bladder tumor cells in culture was examined by light and fluorescence microscopies as well as by histochemical and biochemical studies. The results indicate that these dyes are localized primarily in the lysosome. The cellular uptake and retention of these dyes is energy- and pH-dependent. Agents such as nigericin, which alter the transmembrane pH gradient, reduced uptake and enhanced efflux of the dyes, while agents such as valinomycin, which reduce cellular membrane potential, had no effect on the uptake. These findings are consistent with having ion-trapping as the mechanism for the uptake of these dyes. Photoirradiation of sensitizer-treated cells obliterated lysosomes in a light-dose and drug-dose dependent fashion. Release of the hydrolytic enzymes may be the main cause for subsequent cell death since the cytolytic effect was reduced by a specific inhibitor of lysosomal proteolytic enzyme. A lysosomotropic photosensitization mechanism is therefore proposed for the photocytotoxic action of the Nile blue derivatives. This mechanism may provide an approach to the development of new photosensitizers for the effective and selective destruction of malignant tumors.

Lin, Chi-Wei; Shulok, Janine R.; Kirley, S. D.; Cincotta, Louis; Foley, James W.

1991-06-01

305

Managing foreign exchange risk with derivatives  

Microsoft Academic Search

This study investigates the foreign exchange risk management program of HDG Inc. (pseudonym), a US-based manufacturer of durable equipment. Precise examination of factors affecting why and how the firm manages its foreign exchange exposure are explored through the use of internal firm documents, discussions with managers, and data on3,110 foreign-exchange derivative transactions. Informational asymmetries, facilitation of internal contracting, and competitive

Gregory W. Brown

2001-01-01

306

Triamine chelants, their derivatives, complexes and conjugates  

DOEpatents

A group of functionalized triamine chelants and their derivatives that form complexes with radioactive metal ions are disclosed. The complexes can be covalently attached to a protein or an antibody or antibody fragment and used for therapeutic and/or diagnostic purposes. The chelants are of the formula: ##STR1## wherein n, m, R, R.sup.1, R.sup.2 and L are defined in the specification.

Troutner, David E. (Phoenixville, PA); John, Christy S. (Gaithersburg, MD); Pillai, Maroor R. A. (Vashi, IN)

1995-01-01

307

Joint moments of derivatives of characteristic polynomials  

Microsoft Academic Search

We investigate the joint moments of the 2k-th power of the characteristic\\u000apolynomial of random unitary matrices with the 2h-th power of the derivative of\\u000athis same polynomial. We prove that for a fixed h, the moments are given by\\u000arational functions of k, up to a well-known factor that already arises when\\u000ah=0. We fully describe the denominator in

Paul-Olivier Dehaye

2008-01-01

308

Deriving test plans from architectural descriptions  

Microsoft Academic Search

The paper presents an approach to derive test plansfor the conformance testing of a system implementationwith respect to the formal description of its SoftwareArchitecture (SA). The SA describes a system in termsof its components and connections, therefore the derivedtest plans address the integration testing phase.We base our approach on a Labelled Transition System(LTS) modeling the SA dynamics, and on suitable

Antonia Bertolino; Flavio Corradini; Henry Muccini

2000-01-01

309

Substituted imidazole derivatives as novel cardiovascular agents  

Microsoft Academic Search

A series of novel substituted imidazole derivatives were synthesized and have been screened in vivo for their hypotensive and acute toxicity activities. Out of seventeen compounds eight compounds (2b, 2c, 3b, 3c, 3f, 4a, 4b and 4c) have shown good hypotensive and bradycardiac responses. Compounds 3b, 3c, 3f and 4c have shown better activity than reference drug clonidine. All the

Vineet Malhotra; Seema R. Pathak; Rajendra Nath; Devashish Mukherjee; K. Shanker

2011-01-01

310

Pentacene Derivatives: Electronic Structure and Spectra  

NASA Astrophysics Data System (ADS)

The variation in composition and structure of the substituent groups of pentacene compounds promises a broad range of electronic structures and behaviors and provides a vast and alluring field of inquiry with avenues of exploration. These include the development of synthetic schema, the process of design for novel derivatives and, in order to identify those hypothesized compounds which demonstrate the desired behavior, the identification and refinement of computational tools that make accurate predictions about the electronic behavior of theoretical compounds. Two computational techniques and six pentacene derivatives are here examined. One technique was used to predict the vibrational spectra of the compounds, in order to both acquire data about the optical conductivity of the compounds and to establish a pool of theoretical data against which experimental data will be compared. The molecular orbital energy level diagram of the same six compounds was derived using a second approach, with the same goals of discerning between valid and invalid predictive schema by comparison with pending experimental data and between hypothesized compounds which show promise and those which present little potential for use in organic semiconductor technology.

Netusil, Ross; Ilie, Carolina; Kane, Thorin; Damkaci, Fehmi

2013-03-01

311

Batch separation of uracil derivatives from urine.  

PubMed

Commercial mixed-bed deionizing resins have been modified by conversion to the sulfonic acid and acetate forms and used to prepare extracts of urine that contains uracil derivatives (pKa greater than 8). A rapid batch extraction process, requiring less than 15 min is described for the first time that can be used either for rapid spectrophotometric screening of altered levels of these uracil derivatives or for accurate measurement of uracil and pseudouridine by high-performance liquid chromatography on reversed-phase columns using 0.002 M ammonium formate (pH 6) in water as the solvent. The spectrophotometric assay is based on the spectral shift of uracil derivatives when neutral aqueous solutions are made alkaline. After the batch extraction, the factor for conversion of absorbancy change to nmol is 0.0046 per nmol/ml for uracil and 0.0035 per nmol/ml for pseudouridine. Pseudouridine levels in two test urines were found to be 24 and 19.3 nmol/mumol of creatinine, which are consistent with published values of 17.6-24. PMID:3711206

Uziel, M

1986-04-25

312

Novel isoquinoline derivatives as antimicrobial agents.  

PubMed

The wide variety of potent biological activities of natural and synthetic isoquinoline alkaloids encouraged us to develop novel antimicrobial isoquinoline compounds. We synthesized a variety of differently functionalized 1-pentyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines (THIQs), including dihydroisoquinolinium salts (2 and 5), methyl pentanoate-THIQ (6), 1-pentanol-THIQ (7), ester derivatives (8-15) and carbamate derivatives (16-23). We employed classic intramolecular Bischler-Napieralski cyclodehydration to generate the isoquinoline core. All the structures were characterized by nuclear magnetic resonance and mass spectrometry. The bactericide and fungicide activities were evaluated for all the synthesized compounds and structure-activity relationships were established. Many compounds exhibited high and broad-range bactericidal activity. Fluorophenylpropanoate ester 13 and the halogenated phenyl- (17, 18) and phenethyl carbamates (21, 22) exerted the most remarkable bactericidal activity. However, few compounds displayed antifungal activity against most of the fungi tested. Among them, chlorinated derivatives like chlorobenzoate and chlorophenylpropanoate esters (10 and 14, respectively) and chlorophenethyl carbamate 22, exhibited the greatest antifungal activity. PMID:23601815

Galán, Abraham; Moreno, Laura; Párraga, Javier; Serrano, Ángel; Sanz, Ma Jesús; Cortes, Diego; Cabedo, Nuria

2013-04-02

313

Endplate channel block by guanidine derivatives  

PubMed Central

The effects of the n-alkyl derivatives of guanidine on the frog neuromuscular junction were studied using the two-microelectrode voltage clamp and other electrophysiological techniques. Methyl-, ethyl- , and propylguanidine stimulated the nerve-evoked release of transmitter. However, amyl-and octylguanidine had no apparent presynaptic action. All of the derivatives blocked the postsynaptic response to acetylcholine, the potency sequence being octyl-greater than amyl-greater than propyl-, methyl-greater than ethylguanidine. Methyl- and octylguanidine did not protect the receptor from alpha- bungarotoxin block, suggesting that these compounds do not bind to the receptor but probably block the ionic channel. Methyl-, ethyl-, and propylguanidine shortened inward endplate currents but prolonged outward currents. Amylguanidine prolonged both inward and outward endplate currents, and the currents became biphasic at negative membrane potentials. Octylguanidine increased the rate of decay of endplate currents at all potentials. All of the derivatives blocked inward endplate currents more markedly than outward currents, resulting in a highly nonlinear current-voltage relation. Methyl-, ethyl-, and propylguanidine reversed the voltage dependence of endplate current decay, while amyl-and octylguanidine reduced the voltage dependence of endplate current decay. Octylguanidine appears to block the ionic channel in both the open and the closed state. The block of the open channel follows pseudo-first-order kinetics with a forward rate constant of 4-6 X 10(7) M-1 s-1.

1981-01-01

314

The analgesic potential of clostridial neurotoxin derivatives.  

PubMed

Botulinum neurotoxins are the most potent acute lethal toxins known, and yet for the last two decades they, and in particular serotype A, have found increasing use in the clinical treatment of diseases or conditions involving neuromuscular or autonomic neuronal transmission. The neurotoxins work by inhibiting the release of acetylcholine from peripheral cholinergic nerve terminals. More recently, the effects on non-cholinergic pathways have been identified, and this has led to an increase in the diseases and syndromes for which botulinum neurotoxins have been found to have clinical utility. In particular, botulinum neurotoxins have been demonstrated to potentially benefit a range of chronic pain syndromes. With the description in the last decade of the biochemical basis of neurotoxin action and the tertiary structure of the toxin molecule, the possibility of designing novel agents utilising selected aspects of toxin function has arisen. This possibility has been pursued in the context of pain relief with the description of a novel hybrid protein derived from botulinum neurotoxin type A, LH(N)/A-ECL, able to selectively target nociceptive afferent neurons and inhibit the release of neurotransmitters involved in pain transmission. This novel derivative of botulinum neurotoxin type A demonstrates prolonged analgesic activity in vivo. This review will consider the evidence for the analgesic properties of the botulinum neurotoxins and their suitability as the basis for novel therapeutic proteins. The general concept of deriving novel therapeutic molecules from the neurotoxins will also be considered. PMID:15500391

Foster, Keith A

2004-11-01

315

Indirubin derivatives inhibit malignant lymphoid cell proliferation.  

PubMed

Indirubin-3'-monoxime (IO) is a derivative of indirubin, an active compound of a traditional Chinese medicinal recipe used to treat various inflammatory and malignant diseases. The main in vitro targets of IO (i.e. cyclin dependent kinases, glycogen synthase kinase-3beta, Stat 3 and Aryl hydrocarbon receptor) are regulators of lymphocyte activation. We investigated the interest of IO and its derivative 6-bromo-indirubin-3'oxime (6BIO) for inhibiting the growth of malignant lymphoid cells. IO (1-20 microM) induced cell cycle inhibition and cell death in malignant B- (IM9, Reh6) and T- (Jurkat, CEM-T) lymphoid cell lines depending to cell type, doses, and duration of treatment. IO and 6BIO (10 microM) treatment for 24 and 48 h were compared: 6BIO treatment resulted in a stronger cytotoxicity and more profound inhibition of cell proliferation. Taken together, these results showed that IO and, moreover, its derivative 6BIO may be potent antiproliferative agents in malignant lymphoid cells. PMID:19860623

Chebel, Amel; Kagialis-Girard, Sandrine; Catallo, Regine; Chien, Wei Wen; Mialou, Valérie; Domenech, Carine; Badiou, Cedric; Tigaud, Isabelle; Ffrench, Martine

2009-12-01

316

New saccharin derivatives as tyrosinase inhibitors.  

PubMed

A newly series of 6-(phenylurenyl/thiourenyl) saccharin (6a-y) derivatives were synthesized and their inhibitory effects on the diphenolase activity of banana tyrosinase were evaluated. A 70-fold purification of the enzyme with 6.85% yield was achieved by using a Sepharose 4B-l-tyrosine-p-amino benzoic acid affinity column. The result showed that all the synthesized compounds inhibited the tyrosinase enzyme activity. Among the compounds synthesized, 6-(3-iodophenylthiourenyl) saccharin (6s) was found to be most active one (K(i)=3.95 ?M) and the inhibition kinetics analyzed by Lineweaver-Burk double reciprocal plots revealed that compound 6s was a competitive inhibitor. Structure-activity relationships study showed that generally, most of the 6-(phenylthiourenyl) saccharin derivatives (6m-y) exhibited higher inhibitory activity than 6-(phenylurenyl) saccharin derivatives (6a-l). An electron-withdrawing group at 3-position of phenylurenyl-ring increased in activity and the halogen series at 3-position of phenylthiourenyl-ring showed a qualitative relationship for higher inhibitory activity with increasing size and polarizability. We also calculated HOMO-LUMO energy levels and dipole moments of some selected the synthesized compounds (6a, 6h, 6m and 6s) using Gaussian software. PMID:22494841

Gençer, Nahit; Demir, Dudu; Sonmez, Fatih; Kucukislamoglu, Mustafa

2012-03-23

317

Parallel FFT approach for derivative pricing  

NASA Astrophysics Data System (ADS)

Pricing of derivatives is one of the central problems in Computational Finance. Since the theory of derivative pricing is highly mathematical, numerical techniques such as lattice approach, finite-difference and finite-element techniques among others have been resorted in the past. Recently Fast Fourier Transform (FFT) have been used for such applications as derivative pricing. In the current work, we develop a parallel algorithm for FFT and implement it to price options. Our main aim is to study the performance of this algorithm. For a data size of N and P processors, a blocked data distribution for the algorithm in general produces log(N) - log(P) iterations of local communications and log(P) iterations of remote communications. Therefore, the algorithm is divided into two parts: local and remote. In the local algorithm, the processors perform the computations on their locally partitioned data elements without any communications. In the case of remote algorithm, the processors perform the computation on the local data elements with remote communications. In this paper we focus on the remote communication and computation aspect of the algorithm. We discuss the performance of our algorithm and the results (in general terms) from FFT algorithm and binomial tree algorithm developed and implemented for the same/similar problem. We make some general observation on these two algorithms.

Thulasiram, Ruppa K.; Thulasiraman, Parimala

2001-07-01

318

Comparison of NOAA's Operational AVHRR-Derived Cloud Amount to Other Satellite-Derived Cloud Climatologies  

Microsoft Academic Search

A comparison is made between a new operational NOAA Advanced Very High Resolution Radiometer (AVHRR) global cloud amount product to those from established satellite-derived cloud climatologies. The new operational NOAA AVHRR cloud amount is derived using the cloud detection scheme in the extended Clouds from AVHRR (CLAVR-x) system. The cloud mask within CLAVR-x is a replacement for the Clouds from

Sarah M. Thomas; Andrew K. Heidinger; Michael J. Pavolonis

2004-01-01

319

Estimation of samples of the derivative of a signal based on the signal difference derivative  

Microsoft Academic Search

A technique of designing a discrete-time FIR filter called A-DD for converting the backward difference derivative of a discrete-time signal into a train of samples of the first order derivative of the analogue counterpart of this signal is presented. The power of the proposed technique is illustrated by showing the performance of the Lagrangian A-DD, offering very high accuracy in

Ewa Hermanowicz

2001-01-01

320

Facile (Triazolyl)methylation of MACOS-derived Benzofused Sultams Utilizing ROMP-derived OTP Reagents  

PubMed Central

A combination of MACOS scale-out and ROMP-derived oligomeric triazole phosphates (OTPn) have been successfully utilized for the preparation of a 106-member library of triazole containing benzothiaoxazepine-1,1-dioxides. This report demonstrates the utilization of a suite of soluble OTPn reagents for facile (triazolyl)methylation of 10 MACOS-derived sultam scaffolds in purification-free process for parallel synthesis of small molecule collections for HTS.

Faisal, Saqib; Ullah, Farman; Maity, Pradip K.; Rolfe, Alan; Samarakoon, Thiwanka B.; Porubsky, Patrick; Neuenswander, Benjamin; Lushington, Gerald H.; Basha, Fatima Z.; Organ, Michael G.

2012-01-01

321

Facile (triazolyl)methylation of MACOS-derived benzofused sultams utilizing ROMP-derived OTP reagents.  

PubMed

A combination of MACOS scale-out and ROMP-derived oligomeric triazole phosphates (OTP(n)) have been successfully utilized for the preparation of a 106-member library of triazole containing benzothiaoxazepine-1,1-dioxides. This report demonstrates the utilization of a suite of soluble OTP(n) reagents for facile (triazolyl)methylation of 10 MACOS-derived sultam scaffolds in purification-free process for parallel synthesis of small molecule collections for HTS. PMID:22384820

Faisal, Saqib; Ullah, Farman; Maity, Pradip K; Rolfe, Alan; Samarakoon, Thiwanka B; Porubsky, Patrick; Neuenswander, Benjamin; Lushington, Gerald H; Basha, Fatima Z; Organ, Michael G; Hanson, Paul R

2012-03-05

322

Advances in temperature derivative control and calorimetry  

SciTech Connect

Temperature stabilization by inertial feedback control has proven a powerful tool to create the ultrastable environment essential for high resolution calorimetry. A thermally insulated mass, connected to a base through Seebeck effect sensors (thermopiles) is used as a reference to control the base temperature. The thermopile signal is proportional to both the heat capacity of the reference mass and the derivative {dot {Theta}} of the base temperature {Theta}. Using vacuum insulation and bismuth telluride thermopiles, we designed and tested temperature derivative sensors (TDSs) with sensitivities up to 3300 VsK{sup {minus}1}. Standard industrial controllers with approximately {plus_minus}1 {mu}V input noise and stability, permit control of temperature derivatives to {plus_minus}3{times}10{sup {minus}10} Ks{sup {minus}1}. Single-cup thermoelectric calorimeters coupled to the TDS-controlled base permitted measurement of heat flow from samples in a power range from 3 {mu}W to 10 W with high accuracy ({plus_minus}100 ppm), resolution ({plus_minus}0.2 {mu}W), and reproducibility ({plus_minus}1 {mu}W). The design of two instruments is described in detail. Their performance is demonstrated on a variety of measurements, e.g., the determination of sample heat capacities with temperature ramp rates {dot {Theta}}={plus_minus}5{times}10{sup {minus}6} Ks{sup {minus}1}, the half-life of a 3 g tritium sample in a uranium getter bed, the decay heat of depleted uranium, and the heat evolution of epoxy resin. {copyright} {ital 1996 American Institute of Physics.}

Hemmerich, J.L.; Loos, J.; Miller, A.; Milverton, P. [JET Joint Undertaking, Abingdon, Oxon OX14 3EA (United Kingdom)

1996-11-01

323

Biologic Rhythms Derived from Siberian Mammoths Hairs  

SciTech Connect

Hair is preserved for millennia in permafrost; it enshrines a record of biologic rhythms and offers a glimpse at chronobiology as it was in extinct animals. Here we compare biologic rhythms gleaned from mammoth's hairs with those of modern human hair. Four mammoths' hairs came from varying locations in Siberia 4600 km, four time zones, apart ranging in age between 18,000 and 20,000 years before present. We used two contemporaneous human hairs for comparison. Power spectra derived from hydrogen isotope ratios along the length of the hairs gave insight into biologic rhythms, which were different in the mammoths depending on location and differed from humans. Hair growth for mammoths was {approx}31 cms/year and {approx}16 cms/year for humans. Recurrent annual rhythms of slow and fast growth varying from 3.4 weeks/cycles to 8.7 weeks/cycles for slow periods and 1.2 weeks/cycles to 2.2 weeks/cycles for fast periods were identified in mammoth's hairs. The mineral content of mammoth's hairs was measured by electron microprobe analysis (k-ratios), which showed no differences in sulfur amongst the mammoth hairs but significantly more iron then in human hair. The fractal nature of the data derived from the hairs became evident in Mandelbrot sets derived from hydrogen isotope ratios, mineral content and geographic location. Confocal microscopy and scanning electron microscopy showed varied degrees of preservation of the cuticle largely independent of age but not location of the specimens. X-ray fluorescence microprobe and fluorescence computed micro-tomography analyses allowed evaluation of metal distribution and visualization of hollow tubes in the mammoth's hairs. Seasonal variations in iron and copper content combined with spectral analyses gave insights into variation in food intake of the animals. Biologic rhythms gleaned from power spectral plots obtained by modern methods revealed life style and behavior of extinct mega-fauna.

M Spilde; A Lanzirotti; C Qualls; G Phillips; A Ali; L Agenbroad; O Appenzeller

2011-12-31

324

Biologic rhythms derived from Siberian mammoths' hairs.  

PubMed

Hair is preserved for millennia in permafrost; it enshrines a record of biologic rhythms and offers a glimpse at chronobiology as it was in extinct animals. Here we compare biologic rhythms gleaned from mammoth's hairs with those of modern human hair. Four mammoths' hairs came from varying locations in Siberia 4600 km, four time zones, apart ranging in age between 18,000 and 20,000 years before present. We used two contemporaneous human hairs for comparison. Power spectra derived from hydrogen isotope ratios along the length of the hairs gave insight into biologic rhythms, which were different in the mammoths depending on location and differed from humans. Hair growth for mammoths was ?31 cms/year and ?16 cms/year for humans. Recurrent annual rhythms of slow and fast growth varying from 3.4 weeks/cycles to 8.7 weeks/cycles for slow periods and 1.2 weeks/cycles to 2.2 weeks/cycles for fast periods were identified in mammoth's hairs. The mineral content of mammoth's hairs was measured by electron microprobe analysis (k-ratios), which showed no differences in sulfur amongst the mammoth hairs but significantly more iron then in human hair. The fractal nature of the data derived from the hairs became evident in Mandelbrot sets derived from hydrogen isotope ratios, mineral content and geographic location. Confocal microscopy and scanning electron microscopy showed varied degrees of preservation of the cuticle largely independent of age but not location of the specimens. X-ray fluorescence microprobe and fluorescence computed micro-tomography analyses allowed evaluation of metal distribution and visualization of hollow tubes in the mammoth's hairs. Seasonal variations in iron and copper content combined with spectral analyses gave insights into variation in food intake of the animals. Biologic rhythms gleaned from power spectral plots obtained by modern methods revealed life style and behavior of extinct mega-fauna. PMID:21747920

Spilde, Mike; Lanzirotti, Antonio; Qualls, Clifford; Phillips, Genevieve; Ali, Abdul-Mehdi; Agenbroad, Larry; Appenzeller, Otto

2011-06-29

325

Photooxidative coupling of thiophenol derivatives to disulfides.  

PubMed

Disulfide bonds play an important role in determining the structure and stability of proteins and nanoparticles. Despite extensive studies on the oxidation of thiols for the synthesis of disulfides, little is known about the photooxidation of thiols, which may be a clean, safe, and economical alternative to the use of harmful and expensive metal-containing oxidants and catalysts. In this paper, we report the photooxidative coupling of thiophenol derivatives to disulfides. Para-substituted thiophenol derivatives, p-SHC(6)H(4)X (X = NO(2), COOH, Cl, and OCH(3)), are irradiated, and disulfides, X(2)(C(6)H(4))(2)S(2), are identified as the major photoproducts using Raman, UV-vis, IR, and NMR spectroscopies. For p-nitrothiophenol (pNTP), 4,4'-dinitrodiphenyldisulfide (DNDPDS) is produced in 81% yield. The product yield changes with pH, being the highest at pH ? 5, suggesting that both neutral thiol and anionic thiolate forms of pNTP are required for the photoreaction to occur. Excitation at 455 nm, at which the thiolate form of pNTP absorbs strongly, leads to the largest yield of DNDPDS, whereas very little DNDPDS is formed by excitation of the thiol form of pNTP at 325 nm. Our observations suggest that the photooxidation occurs via collisions of the electronically excited thiolate form of pNTP with the surrounding neutral thiol forms of pNTP. The photooxidation reaction happens regardless of the electron-withdrawing or electron-donating properties of the substituents if the pH and excitation wavelengths are properly chosen. The versatility of light and generality of the photooxidative coupling reaction of thiophenol derivatives may open new possibilities for selective and site-specific photocontrol of disulfide bond formation in biology and nanomaterial science as well as in synthetic chemistry. PMID:20964425

Kim, Hyung Jun; Yoon, Jun Hee; Yoon, Sangwoon

2010-10-22

326

On the derivative discontinuity in molecular junctions  

NASA Astrophysics Data System (ADS)

Both the wave and particle aspects of the electron play essential roles in transport through single-molecule junctions. The wave character is implicit both in the Landauer formula used to understand nanoscale transport and in the very chemical bonds holding the junction together, while the particle aspect is manifested in phenomena such as Coulomb blockade and shot noise. The dominant computational paradigm for transport in single-molecule junctions involves local or semilocal approximations to density functional theory combined with nonequilibrium Green's functions. This approach does exceptionally well at describing the wave aspect of the electron, but fails to describe the particle aspect---due to the omission of the derivative discontinuity in the exchange-correlation potential that arises in the limit of vanishing lead-molecule coupling. To understand the role of the derivative discontinuity in molecular junctions, we investigated the transport and occupancy of a simple Anderson model of a molecular junction. We showedootnotetextJustin P. Bergfield, Zhenfei Liu, Kieron Burke, Charles A. Stafford, arXiv:1106.3104v2 that the exact single-particle Kohn-Sham potential of density functional theory reproduces the linear-response transport of the Anderson model exactly, despite the lack of a Kondo peak in its spectral function. Using Bethe ansatz techniques, we calculated this potential exactly for all coupling strengths, including the cross-over from mean-field behavior to charge quantization caused by the derivative discontinuity. The implications of our results for more complex molecular junctions will be discussed.

Stafford, Charles

2012-02-01

327

Biologic Rhythms Derived from Siberian Mammoths' Hairs  

PubMed Central

Hair is preserved for millennia in permafrost; it enshrines a record of biologic rhythms and offers a glimpse at chronobiology as it was in extinct animals. Here we compare biologic rhythms gleaned from mammoth's hairs with those of modern human hair. Four mammoths' hairs came from varying locations in Siberia 4600 km, four time zones, apart ranging in age between 18,000 and 20,000 years before present. We used two contemporaneous human hairs for comparison. Power spectra derived from hydrogen isotope ratios along the length of the hairs gave insight into biologic rhythms, which were different in the mammoths depending on location and differed from humans. Hair growth for mammoths was ?31 cms/year and ?16 cms/year for humans. Recurrent annual rhythms of slow and fast growth varying from 3.4 weeks/cycles to 8.7 weeks/cycles for slow periods and 1.2 weeks/cycles to 2.2 weeks/cycles for fast periods were identified in mammoth's hairs. The mineral content of mammoth's hairs was measured by electron microprobe analysis (k-ratios), which showed no differences in sulfur amongst the mammoth hairs but significantly more iron then in human hair. The fractal nature of the data derived from the hairs became evident in Mandelbrot sets derived from hydrogen isotope ratios, mineral content and geographic location. Confocal microscopy and scanning electron microscopy showed varied degrees of preservation of the cuticle largely independent of age but not location of the specimens. X-ray fluorescence microprobe and fluorescence computed micro-tomography analyses allowed evaluation of metal distribution and visualization of hollow tubes in the mammoth's hairs. Seasonal variations in iron and copper content combined with spectral analyses gave insights into variation in food intake of the animals. Biologic rhythms gleaned from power spectral plots obtained by modern methods revealed life style and behavior of extinct mega-fauna.

Spilde, Mike; Lanzirotti, Antonio; Qualls, Clifford; Phillips, Genevieve; Ali, Abdul-Mehdi; Agenbroad, Larry; Appenzeller, Otto

2011-01-01

328

QCD sign problem as a total derivative  

NASA Astrophysics Data System (ADS)

We consider the distribution of the complex phase of the fermion determinant in QCD at nonzero chemical potential and examine the physical conditions under which the distribution takes a Gaussian form. We then calculate the baryon number as a function of the complex phase of the fermion determinant and show 1) that the exponential cancellations produced by the sign problem take the form of total derivatives, and 2) that the full baryon number is orthogonal to this noise. These insights allow us to define a self-consistency requirement for measurements of the baryon number in lattice simulations.

Greensite, Jeff; Myers, Joyce C.; Splittorff, K.

2013-08-01

329

Bioactive Polyprenylated Acylphloroglucinol Derivatives from Hypericum cohaerens.  

PubMed

Nine new polyprenylated acylphloroglucinol derivatives, hypercohins B-J (1-9), and nine known analogues were isolated from the aerial parts of Hypericum cohaerens. The structures of 1-9 were elucidated based on spectroscopic analysis, and the absolute configuration of 1 was confirmed by X-ray crystallographic analysis. The inhibitory activities of these isolates on acetylcholinesterase and five human tumor cell lines were tested, and hypercohins B-D (1-3) exhibited moderate inhibitory activity (IC50 5.8-17.9 ?M) against the tested tumor cell lines. PMID:23957453

Liu, Xia; Yang, Xing-Wei; Chen, Chao-Qun; Wu, Chun-Yan; Zhang, Jing-Jing; Ma, Jun-Zeng; Wang, Huan; Yang, Li-Xin; Xu, Gang

2013-08-19

330

Photoactivated insecticidal thiophene derivatives from Xanthopappus subacaulis.  

PubMed

Three new photoactivated insecticidal thiophene derivatives, xanthopappins A-C (1-3), were isolated from Xanthopappus subacaulis, along with three known thiophene acetylenes, 5-hydroxymethyl-2-(E)-hept-5-ene-1,3-diynylthiophene (4), 5-(1,2-dihydroxyethyl)-2-(E)-hept-5-ene-1,3-diynylthiophene (5), and 5-(1,2-diacetoxyethyl)-2-(E)-hept-5-ene-1,3-diynylthiophene (6). The structures of 1-3 were elucidated by spectroscopic methods. Compounds 1-6 exhibited significant photoactivated insecticidal activity against the fourth-instar larvae of the Asian tiger mosquito. PMID:16933888

Tian, Yongqing; Wei, Xiaoyi; Xu, Hanhong

2006-08-01

331

Diphenylurea Derivatives Induce Somatic Embryogenesis in Citrus  

Microsoft Academic Search

The present research investigates the possibility that three diphenylurea (DPU) derivatives, N-phenyl-N?-benzothiazol-6-ylurea (PBU), N,N?-bis-(2,3-methilendioxyphenyl)urea (2,3-MDPU) and N,N?-bis-(3,4-methilendioxyphenyl)urea (3,4-MDPU), stimulate the induction of somatic embryogenesis in three Citrus species. The hypothetical embryogenic activity was assessed using stigma and styles of Citrus myrtifolia Raf., Citrus madurensis Lour. and Citrus limon (L.) Burm. The three compounds influenced the production of somatic embryos differently

Angela Carra; Fabio De Pasquale; Ada Ricci; Francesco Carimi

2006-01-01

332

Cationically polymerizable monomers derived from renewable sources  

SciTech Connect

The objectives of this project are to design and synthesize novel monomers which orginate from renewable biological sources and to carry out their rapid, efficient, pollution-free and energy efficient cationic polymerization to useful products under the influence of ultraviolet light or heat. A summary of the results of the past year's research on cationically polymerizable monomers derived from renewable sources is presented. Three major areas of investigation corresponding to the different classes of naturally occurring starting materials were investigated; epoxidized terpenes and natural rubber and vinyl ethers from alcohols and carbohydrates.

Crivello, J.V.

1992-10-01

333

[Synthesis of potential CCK antagonist quinazolone derivatives].  

PubMed

An original route has been found for the synthesis of [1,4]diazepino-quinazolones, a new ring system of heterocondensed quinazolones. These anthranilicacid-alanin-beta-alanin cyclopeptide derivatives constitute a structural moiety of asperlicin, the first natural cholecystokinin antagonist alkaloid. These compounds are therefore potential CCK antagonists. The new compounds were prepared via condensation of 2-amino-alkyl-quinazolones, obtained from 2-alkyl-quinazolones by side-chain substitution, with 1,3-bifunctional-reagents. We studied the cyclisation process under basic, acidic and phase-transfer catalyzed conditions. The structures of the synthesized compounds were characterized by IR, UV and NMR spectroscopy. PMID:7572196

Szabó, M; Kökösi, J; Orfi, L

1995-07-01

334

Geometric derivation of the chronometric redshift.  

PubMed Central

The chronometric redshift-distance relation z = tan 2(1/2rho), where rho is the distance in radians in the Einstein metric, is derived by an elementary geometric analysis comparable to that in traditional analysis of the expanding universe model. The differential dTt of Einstein time evolution Tt through time t, as applied to the local Minkowski coordinates x, takes the form sec2(1/2t). At the point of observation t = rho, implying that for a sufficiently localized source, observed wave lengths are a factor of sec2(1/2rho) greater than the corresponding emitted wave lengths.

Segal, I E

1993-01-01

335

Synthesis and antiglycation potentials of bergenin derivatives.  

PubMed

Bergenin (1), major bioactive compound isolated from methanolic extract of Mallotus philippinensis, displayed moderate AGE inhibition activity (IC(50)=186.73 ?M). A series of derivatives of bergenin (3a-k) containing variety of aromatic acids were synthesized under mild conditions by modification of sugar part. Selective esterification of hydroxyl groups on the sugar part enhanced antiglycation potential of bergenin. Compounds 3j and 3k exhibited potent antiglycation activity with the IC(50) values of 60.75 and 12.28 ?M, respectively. PMID:21752643

Vijaya Kumar, T; Tiwari, Ashok K; Robinson, A; Suresh Babu, K; Sateesh Chandra Kumar, R; Anand Kumar, D; Zehra, A; Madhusudna Rao, J

2011-05-05

336

Dietary derived compounds in cancer chemoprevention.  

PubMed

Cancer chemoprevention is defined as the application of natural or synthetic agents to suppress or reverse cancer development and progression. In this field especially diet derived compounds have recently attracted researchers' attention as potential therapeutics generally exerting low toxicity compared with regular drugs. This review presents a survey of recent findings concerning the most promising dietary chemopreventive agents such as green tea polyphenols (i.e. catechins), long-chain polyunsaturated fatty acids, carotenoids, glucosinolates/isothiocyanates, vitamins (i.e. vitamin D and folate) and minerals (i.e. calcium and selenium). Molecular targets involved in intrinsic pathways affected by these natural compounds are also shortly discussed. PMID:23788916

Langner, Ewa; Rzeski, Wojciech

2012-11-20

337

The tautomeric forms of cyameluric acid derivatives.  

PubMed

The tautomerism of cyameluric acid C6N7O3H3 (1 a), cyamelurates and other heptazine derivatives has recently been studied by several theoretical investigations. In this experimental study we prepared stannyl and silyl derivatives of cyameluric acid (1 a): C6N7O3[Sn(C4H9)3]3 (3 a), C6N7O3[Sn(C2H5)3]3 (3 b), and C6N7O3[Si(CH3)3]3 (4). In order to investigate the structure of 1 a the mono- and dipotassium cyamelurate hydrates K(C6N7O3H2)2 H2O (5) and K2(C6N7O3H)1 H2O (6) were synthesized by UV/Vis-controlled titration of a potassium cyamelurate solution with aqueous hydrochloric acid. Compounds 3-6 were characterized by FTIR and solid-state NMR spectroscopy as well as simultaneous thermal analysis (TGA, DTA). The single crystal X-ray structures of the salts 5 and 6 show that the hydrogen atoms in both anions are localized on the peripheral nitrogen atoms. This indicates-in combination with the solid-state NMR studies-that the most stable tautomer of solid 1 a is the triketo form with C3h symmetry. However, derivatives of both the hydroxyl and the amido tautomers may be formed depending on the substituent atoms: The spectroscopic data and single crystal structures of compounds C6N7O3[Si(CH3)3]3 (4) and the solvate C6N7O3[Sn(C2H5)3]3C2H4Cl2 (3 b') show that the former is derived from the symmetric trihydroxy form of 1 a, while 3 b' crystallizes as a chain-like polymer, which contains the tin atoms as multifunctional building blocks, that is, bridging pentacoordinated Et3SnO2 and Et3SnON units as well as non-bridging four-coordinated Et3SnN units. The cyameluric nucleus is part of the polymeric chains of C6N7O3[Sn(C2H5)3]3C2H4Cl2 (3 b'), by the action of both tautomeric forms of cyameluric acid, the amide and the ester form. PMID:17120262

El-Gamel, Nadia E A; Seyfarth, Lena; Wagler, Jörg; Ehrenberg, Helmut; Schwarz, Marcus; Senker, Jürgen; Kroke, Edwin

2007-01-01

338

Nonbenzamidine isoxazoline derivatives as factor Xa inhibitors.  

PubMed

Factor Xa (fXa) is an important serine protease in the blood coagulation cascade. Inhibition of fXa has emerged as an attractive target for potential therapeutic applications in the treatments of both arterial and venous thrombosis. Herein, we describe a series of non-benzamidine isoxazoline derivatives as fXa inhibitors. The chloroaniline group was found to be the most potent benzamidine mimic in this series. Chloroaniline 1 (ST368) has a K(i) value of 1.5 nM against fXa and is highly selective for fXa relative to thrombin and trypsin. PMID:12643903

Quan, Mimi L; Ellis, Christopher D; He, Ming Y; Liauw, Ann Y; Lam, Patrick Y S; Rossi, Karen A; Knabb, Robert M; Luettgen, Joseph M; Wright, Matthew R; Wong, Pancras C; Wexler, Ruth R

2003-03-24

339

Endothelium-derived hyperpolarizing factor and diabetes  

PubMed Central

In addition to its role as a barrier between blood and tissues, the vascular endothelium is responsible for the synthesis and released of a number of vasodilators including prostaglandins, nitric oxide and endothelium-derived hyperpolarizing factor (EDHF). As one of these vasodilators, the specific nature of EDHF has not been fully elucidated, although a number of roles have been proposed. Importantly, many conditions, such as hypertension, hyperlipidemia, heart failure, ischemia-reperfusion and diabetes mellitus comprise vascular endothelial dysfunction with EDHF dysregulation. This article reviews reports on the role of EDHF in diabetes-related endothelial dysfunction.

Gao, Xue; Martinez-Lemus, Luis A; Zhang, Cuihua

2011-01-01

340

Numerical approach to the Caputo derivative of the unknown function  

NASA Astrophysics Data System (ADS)

If a function can be explicitly expressed, then one can easily compute its Caputo derivative by the known methods. If a function cannot be explicitly expressed but it satisfies a differential equation, how to seek Caputo derivative of such a function has not yet been investigated. In this paper, we propose a numerical algorithm for computing the Caputo derivative of a function defined by a classical (integer-order) differential equation. By the properties of Caputo derivative derived in this paper, we can change the original typical differential system into an equivalent Caputo-type differential system. Numerical examples are given to support the derived numerical method.

Zeng, Fanhai; Li, Changpin

2013-04-01

341

Classical Derivation of Fermion Operators and Correlations  

NASA Astrophysics Data System (ADS)

A second-order wave equation is derived for an ideal elastic solid. The Klein-Gordon equation is a special case of this equation in which the mass term replaces the nonlinear rotation and convection terms. The second-order wave equation is factored to yield a first order bispinor equation. This equation is similar to the Dirac equation. The corresponding Lagrangian is constructed in terms of bispinors. The quantity conjugate to angular velocity is the quantum mechanical angular momentum. The quantity conjugate to velocity includes the quantum mechanical wave momentum and also the momentum of the medium. Along a given axis there are two independent solutions corresponding to forward- and backward-propagating waves. Since these independent states are separated by 180 degrees, their bispinor wave functions transform under rotation with spin one-half. Potentials are derived from consideration of wave interference. Parity is conserved. The conventional Dirac parity operator is incorrect because it represents a 180 degree rotation rather than inversion of velocity space. Correlations between classical bispinor wave functions are identical to the quantum correlations.

Close, Robert

2009-03-01

342

Derivation of Biomonitoring Equivalents for cyfluthrin.  

PubMed

Recent efforts worldwide have resulted in a growing database of measured concentrations of chemicals in blood and urine samples taken from the general population. However, few tools exist to assist in the interpretation of the measured values in a health risk context. Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of a chemical or its metabolite in a biological medium (blood, urine, or other medium) that is consistent with an existing health-based exposure guideline, and are derived by integrating available data on pharmacokinetics with existing chemical risk assessments. This study reviews available health-based exposure guidance values for cyfluthrin from Health Canada, the United States Environmental Protection Agency (USEPA), and the World Health Organization/Food and Agriculture Organization. BE values corresponding to the oral reference dose (RfD), or acceptable daily intake (ADI) estimates from these agencies were derived based on data on excretion fractions of the urinary metabolite 4-fluoro-3-phenoxybenzoic acid (FPBA), which is a metabolite specific to cyfluthrin. These values may be used as screening tools for evaluation of biomonitoring data for cyfluthrin as the metabolite FPBA in the context of existing risk assessments and for prioritization of the potential need for additional risk assessment efforts for cyfluthrin relative to other chemicals. PMID:19751788

Hays, Sean M; Aylward, Lesa L; Gagné, Michelle; Krishnan, Kannan

2009-09-12

343

Biological activities of isatin and its derivatives.  

PubMed

Isatin is an endogenous compound identified in humans that possesses a wide range of biological activities. Isatin has anxiogenic, sedative, anticonvulsant activities and acts as a potent antagonist on atrial natriuretic peptide receptors in vitro. A series of p-substituted isatin semicarbazones have shown anticonvulsant activity in MES, scPTZ and scSTY tests. Various isatin-N-Mannich bases of isatin-3-thiosemicarbazones have shown antiviral and tuberculostatic activity. Methisazone is an effective compound against variola and vaccinia viruses. The N-dimethyl and morpholino derivative of 5-methyl isatin and trimethoprim exhibited an EC50 of more than 4.3 and 17.7 mg mL(-1), respectively. Isatin (3-o-nitrophenyl) hydrazone has shown activity against Walker carcinoma-256. Various substituted indolinones showed antitubercular activity against M. tuberculosis H37Rv with MIC ranging from 10-20 microg mL(-1). Isatin derivatives of Mannich bases had fibrinolytic, muscle relaxant, antiallergic, immunosuppressant, and antithrombotic activity. Isatin showed cardioinhibitory effect on frog heart, and hypotensive, respiratory depression and antidiuretic effects. PMID:15907222

Pandeya, Surendra Nath; Smitha, Sivakumar; Jyoti, Mayank; Sridhar, Seshaiah Krishnan

2005-03-01

344

Primer on electricity futures and other derivatives  

SciTech Connect

Increased competition in bulk power and retail electricity markets is likely to lower electricity prices, but will also result in greater price volatility as the industry moves away from administratively determined, cost-based rates and encourages market-driven prices. Price volatility introduces new risks for generators, consumers, and marketers. Electricity futures and other derivatives can help each of these market participants manage, or hedge, price risks in a competitive electricity market. Futures contracts are legally binding and negotiable contracts that call for the future delivery of a commodity. In most cases, physical delivery does not take place, and the futures contract is closed by buying or selling a futures contract on or near the delivery date. Other electric rate derivatives include options, price swaps, basis swaps, and forward contracts. This report is intended as a primer for public utility commissioners and their staff on futures and other financial instruments used to manage price risks. The report also explores some of the difficult choices facing regulators as they attempt to develop policies in this area.

Stoft, S.; Belden, T.; Goldman, C.; Pickle, S.

1998-01-01

345

Waste Segregation Based on Derived Clearance Levels  

SciTech Connect

This paper describes the methodology and results of a radiological modeling in support of an application to release very low level radiologically contaminated waste from regulatory control and allow its haulage and disposal in a hazardous waste landfill. The Canadian regulatory body responsible for licensing operations involving nuclear materials (the Canadian Nuclear Safety Commission), has not yet formally defined clearance levels for free release of low level radiologically contaminated waste. The IAEA clearance levels have been derived for certain situations and receptor characteristics, which might be too conservative for an actual case. A site-specific pathways analysis was therefore completed to define conditional clearance levels using the concept of de minimis dose limit. Derived Conditional Clearance Levels were calculated for each radionuclide based on the maximally exposed hypothetical individuals to determine whether each waste stream can be 'cleared' from regulatory controls. The results showed that haulage of the waste from the station to the haulage/processing facility and transportation of waste or sludge from the haulage/processing facility to the disposal facility, handling of the waste or sludge at the haulage/processing facility, and incineration and/or disposal of waste or sludge at the disposal facility would not expose the workers to doses above 0.1 {mu}Sv/yr., which is less than the de minimis dose limit of 10 {mu}Sv/yr. (authors)

Garisto, N.C.; Parhizgari, Z. [SENES Consultants Limited, Richmond Hill, ON (United States)

2008-07-01

346

Derive capillary pressure from well logs  

SciTech Connect

A new approach has been developed to estimate in-situ capillary pressure and relative permeability characteristics in the transition zone. The technique is based on incorporating petrophysical data measured on core samples with well log analysis. Relative permeability can be determined for both drainage and inhibition conditions using the matched capillary pressure data. A technique has been developed to extrapolate petro-physical data where core data is absent or not representative of in-situ conditions. It is based on using log data to derive a water saturation vs. depth profile in the transition zone of the formation of interest. The log-derived water saturation distribution is then correlated to generalized capillary pressure curves typical of the formation studied. The capillary pressure type curves are generated from available core data and other petrophysical information. Relative permeability curves are then generated using correlations based on Purcell's model. The technique can be used in multi-layered and homogeneous reservoirs provided that one homogeneous layer is at least 20 ft thick.

Ibrahim, A. (Suez Canal Univ. (Egypt)); Desbrandes, R.; Bassiouni, Z. (Louisiana State Univ., Baton Rouge, LA (United States))

1994-07-01

347

Siderophore production by marine-derived fungi  

PubMed Central

Siderophore production by marine-derived fungi has not been extensively explored. Three studies have investigated the ability of marine-derived fungi to produce siderophores in response to iron limitation [(Vala et al. in Indian J Mar Sci 29:339-340, 2000; Can J Microbiol 52:603-607, 2006); Baakza et al. in J Exp Mar Biol Ecol 311:1-9, 2004]. In all, 24 of 28 marine fungal strains were found to secrete hydroxamate or carboxylate siderophores; no evidence was found for production of catecholate siderophores. These studies did not determine the structures of the iron-binding compounds. More recently, a study of the natural products secreted by a marine Penicillium bilaii revealed that this strain produced the rare catecholate siderophore pistillarin when grown under relatively high iron concentrations (Capon et al. J Nat Prod 70:1746-1752, 2007). Additionally, the production of rhizoferrin by a marine isolate of Cunninghamella elegans (ATCC36112) is reported in this manuscript. The current state of knowledge about marine fungal siderophores is reviewed in light of these promising results.

Holinsworth, Brian; Martin, Jessica D.

2009-01-01

348

Hydrotreating of coal-derived liquids  

SciTech Connect

The objective of Sandia`s refining of coal-derived liquids project is to determine the relationship between hydrotreating conditions and Product characteristics. The coal-derived liquids used in this work were produced In HTI`s first proof-of-concept run using Illinois No. 8 coal. Samples of the whole coal liquid product, distillate fractions of this liquid, and Criterion HDN-60 catalyst were obtained from Southwest Research Inc. Hydrotreating experiments were performed using a continuous operation, unattended, microflow reactor system. A factorial experimental design with three variables (temperature, (310{degrees}C to 388{degrees}C), liquid hourly space velocity (1 to 3 g/h/cm{sup 3}(cat)), pressure (500 to 1000 psig H{sub 2}) is being used in this project. Sulfur and nitrogen contents of the hydrotreated products were monitored during the hydrotreating experiments to ensure that activity was lined out at each set of reaction conditions. Results of hydrotreating the whole coal liquid showed that nitrogen values in the products ranged from 549 ppM at 320{degrees}C, 3 g/h/cm{sup 3}(cat), 500 psig H{sub 2} to <15 ppM at 400{degrees}C, 1 g/h/ cm{sup 3}(cat), 1000 psig H{sub 2}.

Stohl, F.V.; Lott, S.E.; Diegert, K.V.; Goodnow, D.C.; Oelfke, J.B.

1995-06-01

349

[Antioxidant activity of hydroxy derivatives of coumarin].  

PubMed

The inhibition efficiency (antioxidant activity) of hydroxy derivatives of coumarin, such as esculetin, dicumarol, and fraxetin, was studied in the methemalbumin-H2O2-tetramethylbenzidine (TMB) pseudoperoxidase system at 20 degrees C in a buffered physiological solution (pH 7.4) containing 6% DMF and 0.25% DMSO. The inhibitor's efficiency was quantitatively characterized by the inhibition constants (K(i), microM) and the inhibition degree (%). The K(i) values for esculetin, dicumarol, and fraxetin were 9.5, 15, and 26 microM, respectively. Esculetin and fraxetin inhibited pseudoperoxidase oxidation of TMB in a noncompetitive manner; dicumarol, in a mixed manner. The inhibiting activity ofesculetin in peroxidase-catalyzed TMB oxidation at pH 6.4 is characterized by a K(i) value equal to 1.15 microM, and the inhibition process is competitive. Esculetin was found to be the most effective antioxidant of plant origin among all derivatives previously studied in model biochemical systems. PMID:22834298

Potapovich, M V; Metelitsa, D I; Shadyro, O I

350

Hyperspectral derivatives analysis for intertidal habitat mapping  

NASA Astrophysics Data System (ADS)

Analysis of coastal marine algae communities enables an estimation of the state of coastal marine environments and provides evidence for environmental changes. Hyperspectral remote sensing provides a tool for mapping macroalgal habitats if the algal communities are spectrally resolvable. We tested the performance of a new approach for determining the distribution of macroalgae communities in the rocky intertidal zone of Helgoland (Germany) using airborne hyperspectral (AISAeagle) data. This new approach calculates the slopes in wavelength regions between specific pigment absorption features and does not rely on absolute reflectance values. The first order derivatives of these wavelength regions form slope bands, which are then classified using a k-Means approach. The new derivatives approach proved to be a time effective possibility for identifying the dominating macroalgae species with sufficient accuracy (Cohan's kappa = 0.70). The method was tested on another AISA data set and turned out to be as a robust (Cohan's kappa = 0.77) and easy-to-use approach for delineating dominant algae communities or habitats, which can be adapted easily to different data sets.

Oppelt, N.; Schulze, F.; Bartsch, I.

2012-09-01

351

Antiviral properties of deazaadenine nucleoside derivatives.  

PubMed

Viral infections have menaced human beings since time immemorial, and even today new viral strains that cause lethal diseases are being discovered with alarming frequency. One major example is HIV, the etiological agent of AIDS, which spread up in the last two decades. Very recently, other virus based diseases such as avian flu have spread fear around the world, and hemorrhagic fevers from central Africa serious threaten human health because of their very deadly effects. New antiviral agents are still greatly needed to counter these menaces. Many scientists are involved in this field of research, and many of the recently discovered effective antiviral compounds are nucleoside analogues. Among those derivatives, deazapurine nucleoside analogues have demonstrated potent inhibitory effect of viral replication. This review reports on recently generated data from preparing and testing deazapurine nucleoside derivatives as inhibitors in virus replication systems. Although most of the reported data have been produced in antiHIV, antiHCMV, and antiHSV biological testing, very recently other new important fields of application have been discovered, all in topical subjects of strong interest. In fact, deazapurine nucleosides have been found to be active as chemotherapeutics for some veterinary systemic viral infections, for which no antiviral drugs are licensed yet. Furthermore, they demonstrated efficacy in the inhibition of Hepatitis C virus replication. Finally, these compounds showed high potency as virucides against Ebola Virus, curing Ebola infected mice with a single dose administration. PMID:17168721

Vittori, S; Dal Ben, D; Lambertucci, C; Marucci, G; Volpini, R; Cristalli, G

2006-01-01

352

Cytotoxic Anthranilic Acid Derivatives from Deep Sea Sediment-Derived Fungus Penicillium paneum SD-44  

PubMed Central

Five new anthranilic acid derivatives, penipacids A–E (1–5), together with one known analogue (6), which was previously synthesized, were characterized from the ethyl acetate extract of the marine sediment-derived fungus Penicillium paneum SD-44. Their structures were elucidated mainly by extensive NMR spectroscopic and mass spectrometric analysis. The cytotoxicity and antimicrobial activity of the isolated compounds were evaluated. Compounds 1, and 5 exhibited inhibitory activity against human colon cancer RKO cell line, while compound 6 displayed cytotoxic activity against Hela cell line.

Li, Chun-Shun; Li, Xiao-Ming; Gao, Shu-Shan; Lu, Yan-Hua; Wang, Bin-Gui

2013-01-01

353

Electrochemical properties of non-conjugated electrochromic polymers derived from aromatic amine derivatives  

Microsoft Academic Search

The electrochemical and optical properties of two types of non-conjugated electrochromic polymers derived from aromatic amine derivatives (DDP-A, DDB-P) are presented. DDP-A is synthesized by the polymerization of N,N?-dimethyl-N,N?-diphenyl-1,4-phenylenediamine (DDP) and acetaldehyde (A), and DDB-P is polymerized with N,N?-dimethyl-N,N?-diphenylbenzidine (DDB) and propionaldehyde (P). Both DDP-A and DDB-P have a band gap in the ultraviolet region, and are colorless and transparent

Yoshinori Nishikitani; Masaaki Kobayashi; Soichi Uchida; Takaya Kubo

2001-01-01

354

40 CFR 721.10328 - Salt of polyalkylenepolyamine derivative (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Salt of polyalkylenepolyamine derivative (generic...Specific Chemical Substances § 721.10328 Salt of polyalkylenepolyamine derivative (generic...chemical substance identified generically as salt of polyalkylenepolyamine...

2013-07-01

355

21 CFR 184.1282 - Dill and its derivatives.  

Code of Federal Regulations, 2013 CFR

...184.1282 Dill and its derivatives. (a) Dill (American or European) is the herb and seeds from Anethum graveolens L., and dill (Indian) is the herb and seeds from Anethum sowa, D.C. Its derivatives include essential oils,...

2013-04-01

356

21 CFR 173.110 - Amyloglucosidase derived from Rhizopus niveus.  

Code of Federal Regulations, 2013 CFR

...ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.110...derived from Rhizopus niveus. Amyloglucosidase enzyme product, consisting of enzyme derived from Rhizopus niveus, and...

2013-04-01

357

Tandem repeats derived from centromeric retrotransposons  

PubMed Central

Background Tandem repeats are ubiquitous and abundant in higher eukaryotic genomes and constitute, along with transposable elements, much of DNA underlying centromeres and other heterochromatic domains. In maize, centromeric satellite repeat (CentC) and centromeric retrotransposons (CR), a class of Ty3/gypsy retrotransposons, are enriched at centromeres. Some satellite repeats have homology to retrotransposons and several mechanisms have been proposed to explain the expansion, contraction as well as homogenization of tandem repeats. However, the origin and evolution of tandem repeat loci remain largely unknown. Results CRM1TR and CRM4TR are novel tandem repeats that we show to be entirely derived from CR elements belonging to two different subfamilies, CRM1 and CRM4. Although these tandem repeats clearly originated in at least two separate events, they are derived from similar regions of their respective parent element, namely the long terminal repeat (LTR) and untranslated region (UTR). The 5? ends of the monomer repeat units of CRM1TR and CRM4TR map to different locations within their respective LTRs, while their 3? ends map to the same relative position within a conserved region of their UTRs. Based on the insertion times of heterologous retrotransposons that have inserted into these tandem repeats, amplification of the repeats is estimated to have begun at least ~4 (CRM1TR) and ~1 (CRM4TR) million years ago. Distinct CRM1TR sequence variants occupy the two CRM1TR loci, indicating that there is little or no movement of repeats between loci, even though they are separated by only ~1.4 Mb. Conclusions The discovery of two novel retrotransposon derived tandem repeats supports the conclusions from earlier studies that retrotransposons can give rise to tandem repeats in eukaryotic genomes. Analysis of monomers from two different CRM1TR loci shows that gene conversion is the major cause of sequence variation. We propose that successive intrastrand deletions generated the initial repeat structure, and gene conversions increased the size of each tandem repeat locus.

2013-01-01

358

Dispersant using kraft lignin and novel lignin derivative  

US Patent & Trademark Office Database

The dispersant of the present invention comprises at least one component unit derived from kraft lignin and/or its salt and at least one component unit derived from at least one water-soluble monomer. The novel lignin derivative of the present invention comprises at least one component unit derived from kraft lignin and/or its salt, at least one polyoxyalkylene chain, and at least one anionic functional group.

Tomita; Takashi (Toyonaka, JP); Hirata; Tsuyoshi (Kobe, JP)

2010-04-06

359

Molluscicidal activity of synthetic lapachol amino and hydrogenated derivatives.  

PubMed

A series of new amino derivatives and a new partially hydrogenated derivative of the natural naphthoquinone lapachol were assayed for molluscicidal activity against Biomphalaria glabrata. These derivatives showed low to medium LC(50) values, and a 3.1 microg/mL value for the most potent derivative of the series. The toxicity is in agreement with the decrease of polar character of the tested compounds. PMID:15582464

Silva, Tania M S; Camara, Celso A; Barbosa, Ticiano P; Soares, André Z; da Cunha, Luciana C; Pinto, Angelo C; Vargas, Maria D

2005-01-01

360

Alternative derivation of the response of interferometric gravitational wave detectors  

SciTech Connect

It has recently been pointed out by Finn that the long-standing derivation of the response of an interferometric gravitational wave detector contains several errors. Here I point out that a contemporaneous derivation of the gravitational wave response for spacecraft doppler tracking and pulsar timing avoids these pitfalls, and when adapted to describe interferometers, recovers a simplified version of Finn's derivation. This simplified derivation may be useful for pedagogical purposes.

Cornish, Neil J. [Department of Physics, Montana State University, Bozeman, Montana 59717 (United States)

2009-10-15

361

Computing derivatives of a gravity potential by using automatic differentiation  

NASA Astrophysics Data System (ADS)

A new method, based on automatic differentiation technique, has been proposed in this paper to compute the derivatives of the gravity potential. Using this method we can obtain derivatives up to any order. Instead of explicit expressions of the derivatives we use an iterative scheme to simultaneously compute the value of all the desired derivatives. The algorithm here presented can be easily parallelized by using OpenMP with the consequent improvement in CPU-time efficiency.

Abad, Alberto; Lacruz, Elvis

2013-10-01

362

Derivation of the Freundlich Adsorption Isotherm from Kinetics  

ERIC Educational Resources Information Center

|The Freundlich adsorption isotherm is a useful description of adsorption phenomena. It is frequently presented as an empirical equation with little theoretical basis. In fact, a variety of derivations exist. Here a new derivation is presented using the concepts of fractal reaction kinetics. This derivation provides an alternative basis for…

Skopp, Joseph

2009-01-01

363

Time derivatives of screws with applications to dynamics and stiffness  

Microsoft Academic Search

Screw quantities provide geometric insight into three-dimensional mechanics modeled by rigid bodies and lumped parameters. Four distinct cases of time differentiation are examined by combining fixed and moving body derivatives (fundamental to rigid body mechanics) with material and local derivatives (fundamental to continuum mechanics). Three combinations always yield another screw quantity while the most common, the material derivative with respect

Harvey Lipkin

2005-01-01

364

40 CFR 721.10317 - Alkyl phosphate derivative (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Alkyl phosphate derivative (generic). 721.10317...Chemical Substances § 721.10317 Alkyl phosphate derivative (generic). (a) Chemical...substance identified generically as alkyl phosphate derivative (PMN P-02-1040)...

2013-07-01

365

Simplified Derivation of the Fokker-Planck Equation.  

ERIC Educational Resources Information Center

Presents an alternative derivation of the Fokker-Planck equation for the probability density of a random noise process, starting from the Langevin equation. The derivation makes use of the first two derivatives of the Dirac delta function. (Author/GA)

Siegman, A. E.

1979-01-01

366

Synthesis, antifungal, and antiviral activity of hydrophosphoryl derivatives of mycoheptin  

Microsoft Academic Search

Reactions of the polyene macrolide antibiotic mycoheptin with aldehydes and hypophosphorous acid yielded its hydrophosphoryl\\u000a derivatives. The physicochemical and biological properties the resulting mycoheptin derivatives were studied. Biological investigations\\u000a showed that hydrophosphoryl derivatives of mycoheptin were less toxic than the initial antibiotic and had antifungal and antiviral\\u000a activity.

V. V. Belakhov; Yu. L. Shenin

2007-01-01

367

Critique of Home and Sengupta's derivation of a Bell inequality  

NASA Astrophysics Data System (ADS)

Home and Sengupta claim to derive a Bell-type inequality without assuming locality. I show that their derivation implicitly assumes determinism and a weak locality condition. Their derivation also relies upon further, highly implausible conditions that severely limit the physical implications of their argument.

Elby, Andrew

1990-08-01

368

Pricing Derivatives on Financial Securities Subject to Credit Risk  

Microsoft Academic Search

This article provides a new methodology for pricing and hedging derivative securities involving credit risk. Two types of credit risks are considered. The first is where the asset underlying the derivative security may default. The second is where the writer of the derivative security may default. The authors apply the foreign currency analogy of R. Jarrow and S. Turnbull (1991)

Robert A. Jarrow; Stuart M. Turnbull

1995-01-01

369

World petroleum-derived sulfur production  

SciTech Connect

Research efforts in new uses for sulfur, among them those of the Sulfur Development Institute of Canada, have resulted in the development of several new product markets. Petroleum and natural gas derived sulfurs are finding use as asphalt extenders in road construction throughout North America and as concrete extenders and substitutes for Portland cement in the construction industries of Mexico and the Middle East. Their use in masonry blocks is now being commercialized. Canada is the world's largest producer of commercial sulfur; 80% of it is used as a processing chemical in the form of sulfuric acid. Saudi Arabia, recently having begun to commercialize its vast resources, is constructing plants for the extraction of sulfur from natural gas and plans to export between 6 and 7 x 10/sup 5/ tons annually, much of it for fertilizer manufacture to India, Tunisia, Italy, Pakistan, Greece, Morocco, and Thailand.

Cantrell, A.

1982-08-02

370

Metabolism of carbohydrate derivatives by Pseudomonas acidovorans.  

PubMed Central

Wild-type Pseudomonas acidovorans strain A1 was unable to grow on glycerol or glucose as sole source of carbon and energy although it grew well on gluconate. Spontaneous glycerol-positive mutants, which apparently had become permeable to glycerol, were readily isolated, but glucose-positive mutants did not occur. P. acidovorans lacked glucose dehydrogenase and glucokinase, which were sufficient to account for its inability to grow on glucose. Gluconate was degraded exclusively via a noncoordinately induced Entner-Doudoroff pathway. Phosphogluconate dehydrogenase was undetectable. In contrast to P. aeruginosa, P. acidovorans possessed a single glyceraldehyde-phosphate dehydrogenase activity, which was NAD+ specific and constitutive, and an inducible pyruvate kinase. Moreover, growth of glycerol-positive strain K2 on glycerol did not induce any of the enzymes related to metabolism of hexosephosphate derivatives as occurs in fluorescent pseudomonads.

Wettermark, M H; Taylor, J R; Rogers, M L; Heath, H E

1979-01-01

371

Metabolism of carbohydrate derivatives by Pseudomonas acidovorans.  

PubMed

Wild-type Pseudomonas acidovorans strain A1 was unable to grow on glycerol or glucose as sole source of carbon and energy although it grew well on gluconate. Spontaneous glycerol-positive mutants, which apparently had become permeable to glycerol, were readily isolated, but glucose-positive mutants did not occur. P. acidovorans lacked glucose dehydrogenase and glucokinase, which were sufficient to account for its inability to grow on glucose. Gluconate was degraded exclusively via a noncoordinately induced Entner-Doudoroff pathway. Phosphogluconate dehydrogenase was undetectable. In contrast to P. aeruginosa, P. acidovorans possessed a single glyceraldehyde-phosphate dehydrogenase activity, which was NAD+ specific and constitutive, and an inducible pyruvate kinase. Moreover, growth of glycerol-positive strain K2 on glycerol did not induce any of the enzymes related to metabolism of hexosephosphate derivatives as occurs in fluorescent pseudomonads. PMID:220214

Wettermark, M H; Taylor, J R; Rogers, M L; Heath, H E

1979-05-01

372

Tumor-derived VEGF modulates hematopoiesis  

PubMed Central

VEGF-induced angiogenesis significantly contributes to tumor growth, invasion and metastasis. However, little is known about its hematopoietic activity during malignant development and progression. Here we show that in a mouse tumor model, tumor-derived VEGF acts as an endocrine-like hormone to induce extramedullary hematopoiesis by targeting distal organs in the host. In tumor-bearing mice, circulating VEGF induced hepatomegaly and splenomegaly owing to vessel dilation, tortuosity and activation of hematopoiesis. Furthermore, VEGFR1 and VEGFR2 were primarily localized in blood vessels rather than hepatocytes or splenocytes, demonstrating that alteration of angiogenic profiles modulates hematopoiesis in these organs. Stimulation of extramedullary hematopoiesis sheds new light on complex biological functions of VEGF and significantly increases our understanding of molecular mechanisms underlying VEGF-induced tumor growth.

2009-01-01

373

Biologically active Mannich bases derived from nitroxoline.  

PubMed

A series of compounds with various basic side chains were derived from 5-nitro-8-hydroxyquinoline (nitroxoline). Aminomethylation of nitroxoline led exclusively to the formation of o-substituted phenolic Mannich bases. Depending on the kind of the primary or secondary amine participating in the Mannich reaction differently substituted compounds were prepared in order to study the influence of the basic side chain on their biological activity. The compound with N-bis(2-hydroxyethyl)amino group exhibited the highest mitodepressant activity determined in a phyto test on Lepidium sativum L. Preliminary test for antibacterial and antifungal activities using standard test microorganisms indicate rather strong antimicrobial properties of several synthesized compounds. PMID:7433493

Movrin, M; Maysinger, D; Marok, E

1980-08-01

374

Towards Tartaric-Acid-Derived Asymmetric Organocatalysts  

PubMed Central

Tartaric acid is one of the most prominent naturally occurring chiral compounds. Whereas its application in the production of chiral ligands for metal-catalysed reactions has been exhaustively investigated, its potential to provide new organocatalysts has been less extensively explored. Nevertheless, some impressive results, such as the use of TADDOLs as chiral H-bonding catalysts or of tartrate-derived asymmetric quaternary ammonium salt catalysts, have been reported over the last decade. The goal of this article is to provide a representative overview of the potential and the limitations of tartaric acid or TADDOLs in the creation of new organocatalysts and to highlight some of the most spectacular applications of these catalysts, as well as to summarize case studies in which other classes of chiral backbones were better suited.

Gratzer, Katharina; Gururaja, Guddeangadi N; Waser, Mario

2013-01-01

375

Derivation of hyperbolic models for chemosensitive movement.  

PubMed

A Chapman-Enskog expansion is used to derive hyperbolic models for chemosensitive movements as a hydrodynamic limit of a velocity-jump process. On the one hand, it connects parabolic and hyperbolic chemotaxis models since the former arise as diffusion limits of a similar velocity-jump process. On the other hand, this approach provides a unified framework which includes previous models obtained by ad hoc methods or methods of moments. Numerical simulations are also performed and are motivated by recent experiments with human endothelial cells on matrigel. Their movements lead to the formation of networks that are interpreted as the beginning of a vasculature. These structures cannot be explained by parabolic models but are recovered by numerical experiments on hyperbolic models. Our kinetic model suggests that some kind of local interactions might be enough to explain them. PMID:15480673

Filbet, Francis; Laurençot, Philippe; Perthame, Benoît

2004-10-07

376

The binding of xanthone derivatives to transthyretin.  

PubMed

A series of xanthone derivatives, isolated from Calophyllum teysmannii var. inophylloide, have been evaluated for their binding affinity to transthyretin. Transthyretin is a plasma protein involved in the transport of thyroxine (T4) and also implicated in amyloid diseases. Using competition-binding studies with the protein natural ligand T4, we have identified one prenylated xanthone with a very strong affinity to transthyretin. Molecular docking simulations show that the flexible tail of the prenylated xanthone could allow favorable molecular interactions. Since this xanthone may play a role in the thyroxine metabolism and/or over the pathogenic process associated with the amyloid disease, these results may be explored for the design of new ligands. PMID:16236271

Maia, Filipe; Almeida, Maria do Rosário; Gales, Luís; Kijjoa, Anake; Pinto, Madalena M M; Saraiva, Maria J; Damas, Ana M

2005-10-19

377

Enhanced cubic optical nonlinearity of oligoazine derivatives  

NASA Astrophysics Data System (ADS)

We report a large positive third-order optical nonlinearity of synthesized oligoazine derivatives (OADs) using z-scan technique at 532 nm by Q-switched Nd:YAG laser. Optical band gap of OADs shrinks with increasing repeated units. Origin of large cubic nonlinearity is in the extensive ?-electron delocalization. We obtained the values of ?R^{(3)} ? (0.78 - 3.98) × 10^{ - 11} esu and ?I^{(3)} ? (0.21 - 1.95) × 10^{ - 11} esu in OADs. Moreover, values of optical nonlinearity of OADs show reasonable agreement with the theoretically predicted values. We have shown OADs could be used as good reverse saturable absorber and self-focusing materials. Optical limiting, due to reverse saturable absorption, has also been successfully demonstrated at 532 nm.

Singh, Vijender; Aghamkar, Praveen; Malik, Rajesh Kumar

2013-08-01

378

Waverider configurations derived from general conical flowfields  

NASA Astrophysics Data System (ADS)

A method based on the computational fluid dynamics (CFD) is presented for a flexible waverider’s design. The generating bodies of this method could be any cones. In addition, either the leading edge or the profile of the scramjet’s inlet is used as the waverider’s definition curve, parameterized by the quadric function, the sigmoid function or the B-spline function. Furthermore, several numerical examples are carried out to validate the method and the relevant codes. The CFD results of the configurations show that all the designs are successful. Moreover, primary suggestions are proposed for practical design by comparing the geometrical and aerodynamic performances of the cone-derived waveriders at Mach 6.

Cui, Kai; Zhao, Dongxu; Yang, Guowei

2007-06-01

379

Cationically polymerizable monomers derived from renewable sources  

SciTech Connect

The objective of this project is to make use of products obtained from renewable plant sources as monomers for the direct production of polymers which can be used for a wide range of plastic applications. In this report is described progress in the synthesis and polymerization of cationically polymerizable monomers and oligomers derived from botanical oils, terpenes, natural rubber, and lignin. Nine different botanical oils were obtained from various sources, characterized and then epoxidized. Their photopolymerization was carried out using cationic photoinitiators and the mechanical properties of the resulting polymers characterized. Preliminary biodegradation studies are being conducted on the photopolymerized films from several of these oils. Limonene was cationically polymerized to give dimers and the dimers epoxidized to yield highly reactive monomers suitable for coatings, inks and adhesives. The direct phase transfer epoxidation of squalene and natural rubber was carried out. The modified rubbers undergo facile photocrosslinking in the presence of onium salts to give crosslinked elastomers. 12 refs., 3 figs., 10 tabs.

Crivello, J.V.

1991-10-01

380

Malaria and artemisinin derivatives: an updated review.  

PubMed

Malaria is the world's most prevalent disease that affects 515-600 million people each year and about 40% of the world's population live at risk for this infection. The prevalence of morbidity and mortality from drug resistant malaria (Plasmodium falciparum) is increasing in most of the developing countries, which is also a global threat because international travel is common now and imported malaria is increasingly a serious problem. Since rapid schizonticidal action of naturally occurring endoperoxides pharmacophore present in artemisinin against drug-resistant malaria has been documented, researchers have focused more on artemisinin analogs than any other antimalarials. In this review, drugs of choice about malaria i.e. artemisinin and its analogus/derivatives (arteether, artemether, artemiside, artemisinin, artemisone, artesunate, dihydroartemisinin) have been discussed in detail e.g. bioavailability, formulation development, stability, combination therapy, additional benefits, drug resistance and toxicity have been reviewed. PMID:24070206

Ansari, Muhammad Tayyab; Saify, Zafar Saeed; Sultana, Nighat; Ahmad, Imran; Saeed-Ul-Hassan, Syed; Tariq, Imran; Khanum, Munawer

2013-11-01

381

Structure activity relationships of selected naphthalene derivatives  

SciTech Connect

Twenty-two derivatives of naphthalene were assayed under an acute static regime with biological activity being monitored as population growth of Tetrahymena pyriformis. Activity varied over one log unit. Substituent constant structure-activity analyses revealed the model, log BR = 0.282Ha + 0.352..pi.. + 0.692F + 0.334/sup 1/X/sub sub//sup v/ - 0.326R + 0.027, to be best and to account for 85% of the variation in log BR (BR, biological response; Ha, hydrogen acceptance; ..pi.., hydrophobic substituent constant; F, polar electronic substituent constant, /sup 1/X/sub sub//sup v/, substituent molar connectivity index; R, resonance electronic substituent constant). The Ha and ..pi.. parameters are the most important, accounting for 71% of the log BR variability. 21 references, 1 figure, 7 tables.

Schultz, T.W.; Dumont, J.N.; Sankey, F.D.; Schmoyer, R.L. Jr.

1983-01-01

382

Tire derived fuel, cofiring with coal  

SciTech Connect

It is estimated that each year, a waste tire is generated for every four persons in this country. Only about 25 percent of these tires are currently recycled. This results in a tremendous ongoing disposal problem for out communities. In the past, waste tires were stored in piles. These tire storage piles are hazardous to nearby communities, as a source of insect breeding grounds and as a dangerous fire hazard. Burial of used tires is a waste of valuable landfill space. One alternative is to use waste tires as a fuel supplement with coal. This paper describes the test program conducted by Illinois Power on the 560 MW cyclone-fired boiler at Baldwin Power Station and reviews national activities related to tire-derived fuel (TDF) cofiring with coal.

Stopek, D.J. (R and D, Decatu, IL (US)); Licklider, P.L. (Power Plant Performance, Decatur, IL (US)); Millis, A.K. (Technical Performance, Baldwin Power Station (US)); Diewald, D.J. (Coal and Yard, Baldwin Power Station (US))

1992-01-01

383

Platelet-Derived Serotonin Mediates Liver Regeneration  

NASA Astrophysics Data System (ADS)

The liver can regenerate its volume after major tissue loss. In a mouse model of liver regeneration, thrombocytopenia, or impaired platelet activity resulted in the failure to initiate cellular proliferation in the liver. Platelets are major carriers of serotonin in the blood. In thrombocytopenic mice, a serotonin agonist reconstituted liver proliferation. The expression of 5-HT2A and 2B subtype serotonin receptors in the liver increased after hepatectomy. Antagonists of 5-HT2A and 2B receptors inhibited liver regeneration. Liver regeneration was also blunted in mice lacking tryptophan hydroxylase 1, which is the rate-limiting enzyme for the synthesis of peripheral serotonin. This failure of regeneration was rescued by reloading serotonin-free platelets with a serotonin precursor molecule. These results suggest that platelet-derived serotonin is involved in the initiation of liver regeneration.

Lesurtel, Mickael; Graf, Rolf; Aleil, Boris; Walther, Diego J.; Tian, Yinghua; Jochum, Wolfram; Gachet, Christian; Bader, Michael; Clavien, Pierre-Alain

2006-04-01

384

Antifungal and antibacterial activities of diarylamidine derivatives.  

PubMed Central

The antifungal and antibacterial properties of a series of 70 diarylamidine derivatives were evaluated. Several of these compounds exhibited considerable antimicrobial potency. A survey of the structure-activity relationship demonstrated that minor structural variations resulted in significant changes of antimicrobial activity. In general, the structural features required for antifungal activity coincided with those required for antibacterial activity. Both the antifungal and the antibacterial properties of the diarylamidines depended on the presence and the positions, of both amidino groups, on the nature of the central bridge connecting the two aryl moieties, and on the nature of these aryl residues (preferably indole). The most active compound was evaluated for its activity against Candida albicans infection in mice.

Anne, J; De Clercq, E; Eyssen, H; Dann, O

1980-01-01

385

Generation of deletion derivatives by targeted transformation of human-derived yeast artificial chromosomes  

Microsoft Academic Search

Mammalian DNA segments cloned as yeast artificial chromosomes (YACs) can be manipulated by DNA-mediated transformation when placed in an appropriate yeast genetic background. A fragmenting vector has been developed that can introduce a yeast telomere and selectable marker into human-derived YACs at specific sites by means of homologous recombination, deleting all sequences distal to the recombination site. A powerful application

W. J. Pavan; P. Hieter; R. H. Reeves

1990-01-01

386

Adipose-derived stromal cells (ASCs).  

PubMed

Adipose-derived stromal cells (ASCs) are now emerging as a good alternative to bone marrow derived mesenchymal stromal cells (BM-MSC) for cellular therapy. Similarly to BM-MSC, ASCs can be easily isolated as adherent fibroblastoid cell population after processing lipoaspirate samples. Lipoaspiration provides a great number of cells, without extensive manipulation. ASCs express classical mesenchymal markers and only at early passages express CD34. ASCs can differentiate in cells of mesodermal lineages, such as adipocytes, osteocytes and condrocytes. ASCs share with BM-MSC the same ability to inhibit the proliferation of allogeneic, activated immune cells, thus affecting in vivo in animal models the onset and course of rheumatoid arthritis (RA), experimental autoimmune encephalomyelitis (EAE), Crohn's disease (CD), ulcerous colitis (UC) and graft-versus-host disease (GvHD). On the other hand, the main molecular pathway involved in this effect is still unclear. On the basis of this functional property, ASCs are used in different clinical trials to treat RA, CD, UC and GvHD. However, the most promising field of clinical application is represented by bone defect repair. Despite the ability to regenerate injured tissues and to block the progression of inflammatory disorders, some authors reported that ASCs can also induce, in in vivo animal models, the growth and vascularization of solid and hematological tumors. Conversely, ASCs have been shown to hamper tumor cell proliferation, reduce cell viability and induce necrosis. Thus, more accurate studies, collaborative protocols, high standardization of methods, and safety controls are required to exclude transformation of transplanted ASCs. PMID:22818214

Bassi, Giulio; Pacelli, Luciano; Carusone, Roberta; Zanoncello, Jasmina; Krampera, Mauro

2012-07-19

387

Polyketides from a Marine-Derived Fungus Xylariaceae sp.  

PubMed Central

Eighteen polyketides (1–18) including six citrinin derivatives, two phenol derivatives, one cyclopentenone, two naphthol derivatives, and seven tetralone derivatives were isolated from the culture broth of a marine-derived fungal strain Xylariaceae sp. SCSGAF0086. Five of these compounds (1, 2, 8, 9, and 10) were new, and their structures were determined by spectroscopic methods. Compounds 4, 6, 7, and 17 showed enzyme-inhibitory activities towards several tested enzymes, and 6 and 7 showed strong antifouling activity against Bugula neritina larvae settlement. This is the first time that the antifouling and enzyme-inhibitory activities of these compounds has been reported.

Nong, Xu-Hua; Zheng, Zhi-Hui; Zhang, Xiao-Yong; Lu, Xin-Hua; Qi, Shu-Hua

2013-01-01

388

Mutilins derivatives: from veterinary to human-used antibiotics.  

PubMed

Mutilins derivatives, which were successfully developed in veterinary medicines such as tiamulin and valnemulin, have regained interest as promising antibacterial agents with potential for human use in the past few years. In 2007, Retapamulin, as the first in a new class of topical antibacterial in the nearly two decades, was approved for use in human skin infections. This review provides a developed process of mutilins derivatives from veterinary to human-used antibiotics and emphasizes the structure activity relationship (SAR) and antibacterial mechanism of mutilins derivatives. Moreover, the semi-synthetic strategy of water-soluble mutilins derivatives and related novel derivatives during 2006-2008 will also be reviewed. PMID:19929813

Hu, Changhua; Zou, Yi

2009-10-01

389

Polyketides from a marine-derived fungus Xylariaceae sp.  

PubMed

Eighteen polyketides (1-18) including six citrinin derivatives, two phenol derivatives, one cyclopentenone, two naphthol derivatives, and seven tetralone derivatives were isolated from the culture broth of a marine-derived fungal strain Xylariaceae sp. SCSGAF0086. Five of these compounds (1, 2, 8, 9, and 10) were new, and their structures were determined by spectroscopic methods. Compounds 4, 6, 7, and 17 showed enzyme-inhibitory activities towards several tested enzymes, and 6 and 7 showed strong antifouling activity against Bugula neritina larvae settlement. This is the first time that the antifouling and enzyme-inhibitory activities of these compounds has been reported. PMID:23697953

Nong, Xu-Hua; Zheng, Zhi-Hui; Zhang, Xiao-Yong; Lu, Xin-Hua; Qi, Shu-Hua

2013-05-21

390

The fate of flat directions in higher derivative gravity  

NASA Astrophysics Data System (ADS)

We discuss the fate of flat directions in higher derivative gravity by studying two explicit examples, namely higher derivative gauged supergravity in five dimensions and higher derivative type IIB string theory in ten dimensions. In the first case, the supersymmetric spinning black hole solution in asymptotically AdS spacetime, found by Gutowski and Reall, is analyzed. In this case we find that the flat direction at the two derivative level is not lifted after addition of higher derivative terms, and as it turns out, this result holds even for non-supersymmetric deformations of the higher derivative action. For the rotating D3-brane solutions in type IIB theory, the dilaton parametrizes a flat direction at leading order, but its fate changes upon including order (?')3 supersymmetric higher derivative corrections to the type IIB action, i.e. its leading value gets fixed.

Banerjee, Nabamita; Dutta, Suvankar; Lodato, Ivano

2013-05-01

391

Decline curve derivative analysis for homogeneous and composite reservoirs  

SciTech Connect

In this study, the rate decline and rate decline derivatives of a constant pressure well are presented for infinite, constant pressure outer boundary, and closed outer boundary homogeneous reservoirs. A rate derivative type curve is provided for these cases as well. The effects of the dimensionless reservoir exterior radius are discussed. Rate decline and rate decline derivatives of a constant pressure well in an infinite composite reservoir are also presented. For composite reservoirs, the effects of mobility ratios and discontinuity distance on both rate decline and rate decline derivatives are presented. Type curves for dimensionless wellbore flow rate derivatives for infinite composite reservoirs are provided. A new correlating group for the derivative type curve is provided, and is different than the correlating group for the rate type curve presented in the past. Finally, an analysis method that comprises type curve and derivative type curve matching to determine the dimensionless variables is proposed and demonstrated with a simulated example.

Demski, J.A.

1987-06-01

392

Pseudoacids. II. 2-Acylbenzoic acid derivatives.  

PubMed

Structures of derivatives of cyclic o-acylbenzoic acids, including the chloride, endo- and exocyclic amides, esters and anhydrides, are examined. 3-Chloro-1(3H)-isobenzofuranone (1), orthorhombic, Pbca, a = 11.616 (5), b = 8.120 (3), c = 15.640 (9) A; 3-methoxy-3-phenyl-1(3H)-isobenzofuranone (3), orthorhombic, P2(1)2(1)2(1), a = 6.923 (2), b = 8.291 (4), c = 21.551 (8) A; 3-hydroxy-3-phenyl-N-propyl-1(3H)-isoindolone (4), orthorhombic, P2(1)2(1)2(1), a = 8.662 (4), b = 9.551 (7), c = 17.649 (14) A; 3-(N-morpholino)-1(3H)-isobenzofuranone (5), triclinic, P1, a = 6.172 (4), b = 11.163 (7), c = 17.33 (2) A, alpha = 105.91 (6), beta = 99.85 (6), gamma = 97.57 (5) degrees; 3-(2'-benzoylbenzoyloxy)-3-phenyl-1(3H)-isobenzofuranone (7), triclinic, P1, a = 9.694 (3), b = 10.505 (4), c = 11.163 (4) A, alpha = 80.58 (3), beta = 80.41 (3), gamma = 76.49 (3) degrees; bis[1(3H)-isobenzofuranone-3-yl]ether (8), monoclinic, I2/a, a = 15.31 (2), b = 6.111 (12), c = 28.30 (5) A, beta = 101.61 (12) degrees. An open oxoacid tertiary amide is also described: N-morpholino 2'-benzoylbenzamide (6): monoclinic, P2(1)/c, a = 6.844 (4), b = 15.696 (8), c = 14.154 (7) A, beta = 99.43 (4). Pseudoacid derivatives form planar isobenzofuran and isoindole rings, and the former aldehyde/ketone carbon-heteroatom endocyclic and exocyclic bond distances show bond length variations which correlate with the relative basicities of the attached groups. Structures of both endocyclic and exocyclic nitrogen pseudoamides are reported as well as examples of the normal-pseudoanhydride and the dipseudoanhydride. PMID:9658555

Valente, E J; Martin, S B; Sullivan, L D

1998-06-01

393

Metabolic effects of thyroid hormone derivatives.  

PubMed

The processes and pathways mediating the intermediary metabolism of carbohydrates, lipids, and proteins are all affected by thyroid hormones (THs) in almost all tissues. Particular attention has been devoted by scientists to the effects of THs on lipid metabolism. Among others, effects related to cholesterol, lipid handling, and cardiac performance have been the subject of study. Many reports are present in the literature concerning the calorigenic effect of THs, with most of them aimed at identifying the molecular basis of this effect. However, at the moment the mechanism(s) underlying the metabolic effects of THs remain to be elucidated. THs exert most of their effects though TH receptors (TRs). However, some effects of THs cannot be explained by a nuclear-mediated pathway, and recently an increasing number of nonnuclear actions have been described, which can provide a regulatory system of which the effects differ from those mediated on the transcriptional level by TRs. Some of the TH derivatives (naturally occurring metabolites and analogs) possess biological activities. TH-related biological effects have been described for physiological products such as tetraiodothyroacetic acid (Tetrac) and triiodothyroacetic acid (Triac) (via oxidative deamination and decarboxylation of thyroxine [T4] and triiodothyronine [T3] alanine chain), 3,3',5'-triiodothyronine (rT3) (via T4 and T3 deiodination), 3,3'-diiodothyronine (3,3'-T2) and 3,5-diiodothyronine (T2) (via T4, T3, and rT3 deiodination), and 3-iodothyronamine (T1AM) and thyronamine (T0AM) (via T4 and T3 deiodination and amino acid decarboxylation), as well as for TH structural analogs, such as 3,5,3'-triiodothyropropionic acid (Triprop), 3,5-dibromo-3-pyridazinone-l-thyronine (L-940901), N-[3,5-dimethyl-4-(4'-hydroxy-3'-isopropylphenoxy)-phenyl]-oxamic acid (CGS 23425), 3,5-dimethyl-4[(4'-hydroxy-3'-isopropylbenzyl)-phenoxy] acetic acid (GC-1), 3,5-dichloro-4[(4-hydroxy-3-isopropylphenoxy)phenyl] acetic acid (KB-141), and 3,5-diiodothyropropionic acid (DITPA). Most of these compounds have interesting properties: counteracting lipid accumulation, reducing cholesterol level, and increasing lipid metabolism without cardiotoxic effects. Hopefully, further studies on basic mechanisms of such compounds will be harbingers of more knowledge on the metabolic effects of TH derivatives and on their possible clinical application. PMID:18279024

Moreno, Maria; de Lange, Pieter; Lombardi, Assunta; Silvestri, Elena; Lanni, Antonia; Goglia, Fernando

2008-02-01

394

Efficient derivation of embryonic stem cells from nuclear transfer and parthenogenetic embryos derived from cryopreserved oocytes.  

PubMed

Deriving histocompatible embryonic stem (ES) cells by somatic cell nuclear transfer (SCNT) and parthenogenetic activation (PA) requires fresh oocytes, which prevents their applications in humans. Here, we evaluated the efficiency of deriving ES cells from mature metaphase II (MII) and immature metaphase I (MI) vitrified oocytes, by PA or SCNT, in a mouse model. We successfully generated ES cell lines from PA (MII and MI) and SCNT (MII and MI) blastocysts. These cell lines expressed genes and antigens characteristic of pluripotent ES cells and produced full-term pups upon tetraploid embryo complementation. This study established an animal model for efficient generation of patient-specific ES cell lines using cryopreserved oocytes. This is a major step forward in the application of therapeutic cloning and parthenogenetic technology in human regenerative medicine and will serve as an important alternative to the iPS cell technology in countries/regions where these technologies are permitted. PMID:20677934

Sung, Li-Ying; Chang, Ching-Chien; Amano, Tomokazu; Lin, Chih-Jen; Amano, Misa; Treaster, Stephen B; Xu, Jie; Chang, Wei-Fang; Nagy, Zsolt Peter; Yang, Xiangzhong; Tian, X Cindy

2010-04-01

395

Antioxidant bibenzyl derivatives from Notholaena nivea Desv.  

PubMed

Four new bibenzyl derivatives were isolated, together with other known bibenzyls, by bioassay-guided fractionation of a CHCl?-MeOH extract of Notholaena nivea Desv. (Pteridaceae) aerial parts. The structures were elucidated by NMR, ESIMS and other spectral analyses. Their antioxidative effects towards superoxide, lipidic peroxidation and the 2,2'-azino-bis-3-ethilbenzothiazoline-6-sulfonic acid (ABTS) radical were assayed. Results showed that the compound 3,12-dihydroxy-5-methoxybibenzyl (6) is the most active compound in the ABTS free-radical scavenging test, while in the coupled oxidation of ?-carotene and linoleic acid assay the compound 5,12-dihydroxy-3-methoxydibenzyl-6-carboxylic acid (1) exerted the highest activity after 1h. A superoxide anion enzymatic test was also carried out and the results were confirmed by an inhibition of xanthine oxidase activity assay. The putative protective role played by compounds 1 and 6 on the injurious effects of reactive oxygen metabolites on the intestinal epithelium, using a Caco-2 human cell line, was investigated. H?O?-induced alterations were prevented by preincubating the cells with compounds 1 and 6. PMID:21415834

Cioffi, Giuseppina; Montoro, Paola; De Ugaz, Olga Lock; Vassallo, Antonio; Severino, Lorella; Pizza, Cosimo; De Tommasi, Nunziatina

2011-03-17

396

Endothelial Cells Derived From Nuclear Reprogramming  

PubMed Central

The endothelium plays a pivotal role in vascular homeostasis, regulating the tone of the vascular wall, and its interaction with circulating blood elements. Alterations in endothelial functions facilitate the infiltration of inflammatory cells and permit vascular smooth muscle proliferation and platelet aggregation. Therefore, endothelial dysfunction is an early event in disease processes including atherosclerosis, and because of its critical role in vascular health the endothelium is worthy of the intense focus it has received. However, there are limitations to studying human endothelial function in vivo, or human vascular segments ex vivo. Thus, methods for endothelial cell culture have been developed and refined. More recently, methods to derive endothelial cells from pluripotent cells have extended the scientific range of human endothelial cell studies. Pluripotent stem cells may be generated, expanded and then differentiated into endothelial cells for in vitro studies. Constructs for molecular imaging can also be employed to facilitate tracking these cells in vivo. Furthermore, one can generate patient-specific endothelial cells to study the effects of genetic or epigenetic alterations on endothelial behavior. Finally, there is the opportunity to apply these cells for vascular therapy. This review focuses on the generation of endothelial cells from stem cells; their characterization by genetic, histological and functional studies; and their translational applications.

Wong, Wing Tak; Huang, Ngan F.; Botham, Crystal M.; Sayed, Nazish; Cooke, John P.

2012-01-01

397

Ouabain receptor binding of hydroxyprogesterone derivatives.  

PubMed Central

1 A specific and sensitive radioreceptor assay ahs been devised which is based on high affinity, saturable binding of 9 nM [3H]-ouabain to the total particulate fraction isolated from dog heart. Ouabain and other cardiac glycosides, including the aglycones, were about equipotent in their ability to displace [3H]-ouabain from its receptor, the IC50s ranging from 10 to 30 nM. 2 The only other substances found to compete significantly in the assay were derivatives of hydroxyprogesterone having a 17 alpha-acetate substituent: chlormadinone acetate, megestrol acetate, cyproterone acetate and medroxyprogesterone acetate, with IC50s of 2, 7.4, 9 and 21 microM, respectively. Prednisolone-3,20-bisguanyl-hydrazone, reported to have inotropic activity, gave an IC50 of 6.4 microM. Cyproterone-17 alpha-OH was less active (IC50 90 microM) than cyproterone-17 alpha-acetate. 3 A large number of peptide and protein hormones, steroid hormones and their metabolites, amines, and drugs were inactive.

Chow, E.; Kim, R. S.; Labella, F. S.; Queen, G.

1979-01-01

398

Dissolution of human teeth-derived hydroxyapatite.  

PubMed

We have been interested in human teeth which consist of hydroxyapatite (HA), but do not degrade for a long time. In order to overcome dissolution and mechanical degradation of man-made HA, biologically derived hydroxyapatite (BHA) ceramics were prepared from human teeth and their dissolving behavior was investigated in distilled water for 3-14 days and compared with an artificial HA made of synthetic HA powder. BHA ceramics were prepared by calcining freshly extracted human teeth at 900 degrees C and followed by sintering at 1200 degrees C for 2 h. All detectable peaks in the artificial HA are identical to HA lattice planes, whereas BHA consisted of a mixture of HA and beta-tricalcium phosphate (TCP). Although the artificial HA was expected to be stable in water, the surface dissolution initiated at grain boundaries followed by generated many separated grains and their associated pores. On the other hand, BHA showed that definite grains considered as beta-TCP were predominantly dissolved and the grains were separated from the matrix leaving pores. In the mean time, the rest region, mainly consisting of HA, did not show any evidence of dissolution. It indicates that BHA showed rather stable grain boundaries and lack of excessive dissolution in liquid environment. PMID:17943445

Seo, Dong Seok; Lee, Jong Kook

2007-10-18

399

Viable transgenic goats derived from skin cells.  

PubMed

The current study was undertaken to evaluate the possibility of expanding transgenic goat herds by means of somatic cell nuclear transfer (NT) using transgenic goat cells as nucleus donors. Skin cells from adult, transgenic goats were first synchronized at quiescent stage (G0) by serum starvation and then induced to exit G0 and proceed into G1. Oocytes collected from superovulated donors were enucleated, karyoplast-cytoplast couplets were constructed, and then fused and activated simultaneously by a single electrical pulse. Fused couplets were either co-cultured with oviductal cells in TCM-199 medium (in vitro culture) or transferred to intermediate recipient goat oviducts (in vivo culture) until final transfer. The resulting morulae and blastocysts were transferred to the final recipients. Pregnancies were confirmed by ultrasonography 25-30 days after embryo transfer. In vitro cultured NT embryos developed to morulae and blastocyst stages but did not produce any pregnancies while 30% (6/20) of the in vivo derived morulae and blastocysts produced pregnancies. Two of these pregnancies were resorbed early in gestation. Of the four recipients that maintained pregnancies to term, two delivered dead fetuses 2-3 days after their due dates, and two recipients gave birth to healthy kids at term. Fluorescence in situ hybridization (FISH) analysis confirmed that both kids were transgenic and had integration sites consistent with those observed in the adult cell line. PMID:15359599

Behboodi, Esmail; Memili, Erdogan; Melican, David T; Destrempes, Margaret M; Overton, Susan A; Williams, Jennifer L; Flanagan, Peter A; Butler, Robin E; Liem, Hetty; Chen, Li How; Meade, Harry M; Gavin, William G; Echelard, Yann

2004-06-01

400

Prediction of thermodynamic properties of coal derivatives  

SciTech Connect

The purpose of this research program is to understand the relationship between macroscopic thermodynamic properties and the various types of intermolecular forces. Since coal-derived liquids contain a wide variety of compounds, a theory capable of successfully predicting the thermophysical properties for coal processes must take into account the molecular shapes and all significant intermolecular forces: dispersion forces, anisotropic forces due to dipoles and quadrupoles, as well as Lewis acid-base interactions. We have developed the Acid-Base-Perturbed-Anisotropic-Chain Theory (ABPACT), a comprehensive theory that is capable of predicting the thermophysical properties for many systems where these different intermolecular forces are present. The ABPACT can treat non-polar compounds, polar compounds and compounds that associate through Lewis acid-base interactions. In addition to our theoretical work, we have used computer simulations to evaluate (and in some cases correct) the assumptions made in this theory. We also have conducted experiments to help us better understand the interplay of different kinds of interactions in multicomponent mixtures.

Donohue, M.D.

1990-09-01

401

Gnotobiotic pigs-derivation and rearing.  

PubMed Central

The procurement, rearing, nutrition and microbiological monitoring of gnotobiotic pigs and a method for conditioning of primary, colostrum-deprived, specific pathogen free pigs is described. As compared to the established hysterectomy and closed hysterotomy methods for the derivation of gnotobiotic piglets an alternative approach, open caesarian section with the sow maintained under general halothane-nitrous oxide anaesthesia and the introduction of each fetus into the sterile isolator via a liquid germicidal trap, was found to be more efficient and equally successful in providing viable and microbiologically sterile piglets. Two sterile commercially available milk diets, a special formula for orphan animals and condensed cow's milk, when the latter was supplemented with injectable vitamin E, selenium and iron, proved adequate for satisfactory health of the animals. Two types of pelleted starter rations, sterilized by 4.5 megarads of gamma irradiation, provided adequately for the nutritional needs of older gnotobiotic pigs. Results of microbiological monitoring indicated that the surgical and rearing methods employed were capable of preventing contamination of the animals with bacteria, mycoplasma, yeasts, molds, protozoa and helminths but probably could not exclude occasional vertically transmitted viral infections. Exposure of the animals for four weeks to selected strains of lactobacilli, fecal streptococci and Escherichia coli did not result in visible disease while they were maintained in isolators and conditioned them for transfer into a conventional microbial environment.

Miniats, O P; Jol, D

1978-01-01

402

Catanionic gels based on cholic Acid derivatives.  

PubMed

In this paper, the preparation and characterization of an anionic and a cationic surfactant obtained by chemical modifications of a natural bile acid (cholic acid) are reported. The bile acid was modified by introducing a diamine or a dicarboxylic aromatic residue on the lateral chain. The pure cationic surfactant self-assembles in a network of fibers with a cross-section gyration radius of about 15.1 Å, providing hydrogels with a pH-dependent compactness. On the other hand, the anionic molecule gives rise to prolate ellipsoid micelles. Homogeneous catanionic mixtures have also been obtained, with molar fraction of each surfactant ranging from 0.125 to 0.875. At total surfactant concentration of 0.05% (w/v), the mixtures form gels of fibrils partially arranged in secondary twisted superstructures. Comparison of this concentration with the minimum gelation concentration of the pure cationic derivative (0.16% w/v) suggests that, in the mixtures, the presence of the electrostatic component in self-assembly of the molecules allows the formation of gels starting from more dilute samples. In view of these achievements, this work suggests that catanionic mixtures can be exploited to enhance the efficiency of gelators. PMID:24063307

di Gregorio, M Chiara; Pavel, N Viorel; Miragaya, Javier; Jover, Aida; Meijide, Francisco; Vázquez Tato, José; Soto Tellini, Victor H; Galantini, Luciano

2013-09-24

403

Urease inhibitory activities of ?-boswellic acid derivatives  

PubMed Central

Background and the purpose of the study Boswellia carterii have been used in traditional medicine for many years for management different gastrointestinal disorders. In this study, we wish to report urease inhibitory activity of four isolated compound of boswellic acid derivative. Methods 4 pentacyclic triterpenoid acids were isolated from Boswellia carterii and identified by NMR and Mass spectroscopic analysis (compounds 1, 3-O-acetyl-9,11-dehydro-?-boswellic acid; 2, 3-O-acetyl-11-hydroxy-?-boswellic acid; 3. 3-O- acetyl-11-keto-?-boswellic acid and 4, 11-keto-?-boswellic acid. Their inhibitory activity on Jack bean urease were evaluated. Docking and pharmacophore analysis using AutoDock 4.2 and Ligandscout 3.03 programs were also performed to explain possible mechanism of interaction between isolated compounds and urease enzyme. Results It was found that compound 1 has the strongest inhibitory activity against Jack bean urease (IC50?=?6.27?±?0.03 ?M), compared with thiourea as a standard inhibitor (IC50?=?21.1?±?0.3 ?M). Conclusion The inhibition potency is probably due to the formation of appropriate hydrogen bonds and hydrophobic interactions between the investigated compounds and urease enzyme active site and confirms its traditional usage.

2013-01-01

404

Myeloid derived suppressor cells in human diseases  

PubMed Central

Myeloid derived suppressor cells (MDSC) have been described as a heterogeneous cell population with potent immune suppressor function in mice. Limited data are available on MDSC in human diseases. Interpretation of these data is complicated by the fact that different markers have been used to analyze human MDSC subtypes in various clinical settings. Human MDSC are CD11b+, CD33+, HLA-DRneg/low and can be divided into granulocytic CD14? and monocytic CD14+ subtypes. Interleukin 4R?, VEGFR, CD15 and CD66b have been suggested to be more specific markers for human MDSC, however these markers can only be found on some MDSC subsets. Until today the best marker for human MDSC remains their suppressor function, which can be either direct or indirect through the induction of regulatory T cells. Immune suppressor activity has been associated with high arginase 1 and iNOS activity as well as ROS production by MDSC. Not only in murine models, but even more importantly in patients with cancer, different drugs have been shown to either reverse the immune suppressor function of MDSC or directly target these cells. Systemic treatment with all-trans-retinoic acid has been shown to mature human MDSC and reverse their immune suppressor function. Alternatively, MDSC can be targeted by treatment with the multi-targeted receptor tyrosine kinase inhibitor sunitinib. In this review will provide a comprehensive summary of the recent literature on human MDSC.

Greten, Tim F.; Manns, Michael P.; Korangy, Firouzeh

2012-01-01

405

Deriving Chesapeake Bay Water Quality Standards  

USGS Publications Warehouse

Achieving and maintaining the water quality conditions necessary to protect the aquatic living resources of the Chesapeake Bay and its tidal tributaries has required a foundation of quantifiable water quality criteria. Quantitative criteria serve as a critical basis for assessing the attainment of designated uses and measuring progress toward meeting water quality goals of the Chesapeake Bay Program partnership. In 1987, the Chesapeake Bay Program partnership committed to defining the water quality conditions necessary to protect aquatic living resources. Under section 303(c) of the Clean Water Act, States and authorized tribes have the primary responsibility for adopting water quality standards into law or regulation. The Chesapeake Bay Program partnership worked with U.S. Environmental Protection Agency to develop and publish a guidance framework of ambient water quality criteria with designated uses and assessment procedures for dissolved oxygen, water clarity, and chlorophyll a for Chesapeake Bay and its tidal tributaries in 2003. This article reviews the derivation of the water quality criteria, criteria assessment protocols, designated use boundaries, and their refinements published in six addendum documents since 2003 and successfully adopted into each jurisdiction's water quality standards used in developing the Chesapeake Bay Total Maximum Daily Load.

Tango, Peter J.; Batiuk, Richard A.

2013-01-01

406

Derivatives and credit contagion in interconnected networks  

NASA Astrophysics Data System (ADS)

The importance of adequately modeling credit risk has once again been highlighted in the recent financial crisis. Defaults tend to cluster around times of economic stress due to poor macro-economic conditions, but also by directly triggering each other through contagion. Although credit default swaps have radically altered the dynamics of contagion for more than a decade, models quantifying their impact on systemic risk are still missing. Here, we examine contagion through credit default swaps in a stylized economic network of corporates and financial institutions. We analyse such a system using a stochastic setting, which allows us to exploit limit theorems to exactly solve the contagion dynamics for the entire system. Our analysis shows that, by creating additional contagion channels, CDS can actually lead to greater instability of the entire network in times of economic stress. This is particularly pronounced when CDS are used by banks to expand their loan books (arguing that CDS would offload the additional risks from their balance sheets). Thus, even with complete hedging through CDS, a significant loan book expansion can lead to considerably enhanced probabilities for the occurrence of very large losses and very high default rates in the system. Our approach adds a new dimension to research on credit contagion, and could feed into a rational underpinning of an improved regulatory framework for credit derivatives.

Heise, S.; Kühn, R.

2012-04-01

407

Methyltriethoxysilane derived coatings for optical applications  

NASA Astrophysics Data System (ADS)

Acid catalyzed solutions of methyltriethoxysilane (MTES) mixed with tetraethoxysilane (TEOS) or titanbutilate (TiBut) were used to deposit silica and silica-titania coatings by dipping and spinning. Inorganic coatings free of cracks were obtained with a thickness up to 1.5 micrometers , after densification at 500 degree(s)C. The MTES derived coatings were used as matrices for metallic nanoparticles. Gold, silver and platinum nanoparticles were obtained in the coatings by thermal reduction. Gold particles were obtained at a temperature of 200 degree(s)C, while temperatures around 800 degree(s)C were necessary for silver and platinum. The effect of the composition of the matrix, the heat treatment temperature and the atmosphere on the formation of the particles was studied. The metallic particles were characterized by transmission electron microscopy, x-ray diffraction and UV-Vis absorption spectroscopy. The content of MTES and the heat treatment temperature were found to affect the dimension and the shape of the metal particles. The distribution in particle size may be tailored by choosing the heat treatment temperature and the amount of MTES.

Innocenzi, Plinio

1994-10-01

408

Ultralow thermal conductivity of fullerene derivatives  

NASA Astrophysics Data System (ADS)

Recently, Duda [J. C. Duda, P. E. Hopkins, Y. Shen, and M. C. Gupta, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.110.015902 110, 015902 (2013)] reported that the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) has the lowest thermal conductivity ? ever observed in a fully dense solid, ? ? 0.03 W m-1 K-1. We have investigated a variety of phases and microstructures of PCBM and the closely related compound [6,6]-phenyl-C61-butyric acid n-butyl ester (PCBNB) and find that the thermal conductivities of PCBM and PCBNB films are mostly limited to the range 0.05 < ? < 0.06 W m-1 K-1 with a few samples having slightly higher ?. The conductivities we observe are ?70% larger than reported by Duda but are still “ultralow” in the sense that the thermal conductivity is a factor of ?3 below the conductivity predicted by the minimum thermal conductivity model using an estimate of the thermally excited modes per molecule.

Wang, Xiaojia; Liman, Christopher D.; Treat, Neil D.; Chabinyc, Michael L.; Cahill, David G.

2013-08-01

409

Antiproliferative activity of new benzimidazole derivatives.  

PubMed

A series of new benzimidazole derivatives were synthesized and tested in vitro for possible anticancer activity. Their effect of proliferation into selected tumor cell lines at normoxia and hypoxia conditions was determined by WST-1 test. Additionally, apoptosis test (caspase 3/7 assay) was used to check the mode caused by the agents of cell death. Four of the examined compounds (7, 8, 13, 11) showed a very good antiproliferative effect and three of them were specific for hypoxia conditions (8, 14, 11). Compound 8 was the most cytotoxic against human lung adenocarcinoma A549 cells at hypoxic conditions. Hypoxia/ normoxia cytotoxic coefficient of compound 14 (4.75) is close to hypoxia/normoxia cytotoxic coefficient of tirapazamine (5.59) - a reference compound in our experiments and this parameter locates it between mitomycin C and 2-nitroimidazole (misonidazole). Screening test of caspase-dependent apoptosis proved that exposure to A549 cells of compounds 7-8 and 13-14 for 48 h promote apoptotic cell death. These results supplement our earlier study of the activity of new potentialy cytotoxic heterocyclic compounds against selected tumor cells. PMID:23888297

B?aszczak-?wi?tkiewicz, Katarzyna; Olszewska, Paulina; Mikiciuk-Olasik, El?bieta

2013-07-25

410

Derived relations and generalized alteration of preferences.  

PubMed

The present study examined the role of derived relations in the generalizability of the evaluative conditioning effect. Healthy university students participated. Four geometrical shapes were first established as discriminative stimuli for the contingent presentation of pictograms (B1, B2, C1, and C2, respectively). We then assessed the reinforcing properties of B1 versus B2, and C1 versus C2 by using simultaneous discrimination tasks: at baseline (baseline assessment), after pairing B1 with aversive slides plus noise and B2 with pleasant slides (test I), and after employing equivalence training and testing to establish B1 as equivalent to C1 and B2 as equivalent to C2 (test II). Most participants (82%) in the experimental condition, as compared with the control conditions (17% and 10%), selected the discriminative shapes for B2 (test I) and C2 (test II) on most trials, replicating and extending previous findings. Subsequently, the geometrical shapes were established as equivalent to the letters X, Y, W, and Z, respectively, which then served as antecedent stimuli in simultaneous discrimination tasks as before (test III). As was expected, only participants in the experimental condition showed preference for the novel letters that were established as equivalent to B2-producing and C2-producing shapes. These findings suggest that the evaluative conditioning effect may extend far beyond the stimulus being de/valuated and narrow the behavioral repertoire. PMID:23242738

Valdivia-Salas, Sonsoles; Dougher, Michael J; Luciano, Carmen

2013-06-01

411

Derivation of dose conversion factors for tritium  

SciTech Connect

For a given intake mode (ingestion, inhalation, absorption through the skin), a dose conversion factor (DCF) is the committed dose equivalent to a specified organ of an individual per unit intake of a radionuclide. One also may consider the effective dose commitment per unit intake, which is a weighted average of organ-specific DCFs, with weights proportional to risks associated with stochastic radiation-induced fatal health effects, as defined by Publication 26 of the International Commission on Radiological Protection (ICRP). This report derives and tabulates organ-specific dose conversion factors and the effective dose commitment per unit intake of tritium. These factors are based on a steady-state model of hydrogen in the tissues of ICRP's Reference Man (ICRP Publication 23) and equilibrium of specific activities between body water and other tissues. The results differ by 27 to 33% from the estimate on which ICRP Publication 30 recommendations are based. The report also examines a dynamic model of tritium retention in body water, mineral bone, and two compartments representing organically-bound hydrogen. This model is compared with data from human subjects who were observed for extended periods. The manner of combining the dose conversion factors with measured or model-predicted levels of contamination in man's exposure media (air, drinking water, soil moisture) to estimate dose rate to an individual is briefly discussed.

Killough, G. G.

1982-03-01

412

Deriving an underlying mechanism for discontinuous percolation  

NASA Astrophysics Data System (ADS)

Understanding what types of phenomena lead to discontinuous phase transitions in the connectivity of random networks is an outstanding challenge. Here we show that a simple stochastic model of graph evolution leads to a discontinuous percolation transition and we derive the underlying mechanism responsible: growth by overtaking. Starting from a collection of n isolated nodes, potential edges chosen uniformly at random from the complete graph are examined one at a time while a cap, k, on the maximum allowed component size is enforced. Edges whose addition would exceed k can be simply rejected provided the accepted fraction of edges never becomes smaller than a function which decreases with k as g(k) = 1/2 + (2k)-?. We show that if ? < 1 it is always possible to reject a sampled edge and the growth in the largest component is dominated by an overtaking mechanism leading to a discontinuous transition. If ? > 1, once k ? n1/?, there are situations when a sampled edge must be accepted leading to direct growth dominated by stochastic fluctuations and a “weakly” discontinuous transition. We also show that the distribution of component sizes and the evolution of component sizes are distinct from those previously observed and show no finite-size effects for the range of ? studied.

Chen, W.; Zheng, Z.; D'Souza, R. M.

2012-12-01

413

Crystalline supramolecular nanofibers based on dehydrobenzoannulene derivatives.  

PubMed

Supramolecular nanofibers (SNFs) composed of low-molecular-weight ?-conjugated molecules exhibit attractive optical and electrical properties and are expected to be the next optoelectronic materials. In this work, five crystalline SNFs have been constructed from three dehydrobenzoannulene (DBA) derivatives. The DBAs were designed to assemble in one dimension in a strategy based on anisotropic crystal growth. The crystallinity of the SNFs allowed the molecular arrangements in the SNFs to be determined. Therefore the mechanism of construction and correlations between the molecular arrangements and optical and electrical properties could be considered. The results clearly indicate that the properties of the SNFs are affected by the chemical structures and molecular arrangements. Moreover, one of the SNFs exhibits a high charge-carrier mobility (??=0.61?cm(2) ?V(-1) ?s(-1) ) because of its crystallinity and appropriate molecular arrangement. This systematic experimental study based on a proposed strategy has provided information for improving the electrical properties of SNFs. This strategy will lead to highly functional SNFs. PMID:24115390

Shigemitsu, Hajime; Hisaki, Ichiro; Kometani, Eriko; Yasumiya, Daisuke; Sakamoto, Yuu; Osaka, Keisuke; Thakur, Tejender S; Saeki, Akinori; Seki, Shu; Kimura, Fumiko; Kimura, Tsunehisa; Tohnai, Norimitsu; Miyata, Mikiji

2013-09-23

414

Photoelectrochemical information storage using an azobenzene derivative  

NASA Astrophysics Data System (ADS)

HIGH-DENSITY information storage is becoming an increasingly important technological objective. The 'heat-mode' storage techniques (in which only the thermal energy of laser light is used in the recording process and hence information usually stored as a physical change of the storage media) that are used in current optical memories are limited by the diffraction properties of light1, and the alternative 'photon-mode' (in which information is stored as a photon-induced chemical change of the storage media) has attracted attention recently for high-density storage. The most promising candidates for realizing this mode seem to be photochro-ism and photochemical hole burning; but these have some intrinsic drawbacks1,2. Here we present a novel 'photon-mode' technique that uses the photoelectrochemical properties of a Langmuir-Blodgett film of an azobenzene derivative. The system can be interconverted photochemically or electrochemically between three chemical states, and this three-state system is shown to provide a potential storage process that allows for ultra-high storage density, multi-function memory and non-destructive information readout.

Liu, Z. F.; Hashimoto, K.; Fujishima, A.

1990-10-01

415

Jet flames of a refuse derived fuel  

SciTech Connect

This paper is concerned with combustion of a refuse derived fuel in a small-scale flame. The objective is to provide a direct comparison of the RDF flame properties with properties of pulverized coal flames fired under similar boundary conditions. Measurements of temperature, gas composition (O{sub 2}, CO{sub 2}, CO, NO) and burnout have demonstrated fundamental differences between the coal flames and the RDF flames. The pulverized coals ignite in the close vicinity of the burner and most of the combustion is completed within the first 300 ms. Despite the high volatile content of the RDF, its combustion extends far into the furnace and after 1.8 s residence time only a 94% burnout has been achieved. This effect has been attributed not only to the larger particle size of fluffy RDF particles but also to differences in RDF volatiles if compared to coal volatiles. Substantial amounts of oily tars have been observed in the RDF flames even though the flame temperatures exceeded 1300 C. The presence of these tars has enhanced the slagging propensity of RDF flames and rapidly growing deposits of high carbon content have been observed. (author)

Weber, Roman; Kupka, Tomasz; Zajac, Krzysztof [Institute of Energy Process Engineering and Fuel Technology, Clausthal University of Technology, Agicolastrasse 4, 38 678 Clausthal-Zellerfeld (Germany)

2009-04-15

416

Antioxidant activities of licorice-derived prenylflavonoids.  

PubMed

Glycyrrhiza uralensis (or licorice) is a widely used Oriental herbal medicine from which the phenylflavonoids dehydroglyasperin C (DGC), dehydroglyasperin D (DGD), and isoangustone A (IsoA) are derived. The purpose of the present study was to evaluate the antioxidant properties of DGC, DGD, and IsoA. The three compounds showed strong ferric reducing activities and effectively scavenged DPPH, ABTS(+), and singlet oxygen radicals. Among the three compounds tested, DGC showed the highest free radical scavenging capacity in human hepatoma HepG2 cells as assessed by oxidant-sensitive fluorescent dyes dichlorofluorescein diacetate and dihydroethidium bromide. In addition, all three compounds effectively suppressed lipid peroxidation in rat tissues as well as H(2)O(2)-induced ROS production in hepatoma cells. This study demonstrates that among the three phenylflavonoids isolated from licorice, DGC possesses the most potent antioxidant activity, suggesting it has protective effects against chronic diseases caused by reactive oxygen species as well as potential as an antioxidant food additive. PMID:23346298

Kim, Hyo Jung; Seo, Ji-Yeon; Suh, Hwa-Jin; Lim, Soon Sung; Kim, Jong-Sang

2012-12-31

417

Occupationally derived chemicals in breast milk  

SciTech Connect

Exogenously derived chemicals have been widely reported in breast milk. Chemicals typically found in occupational exposures, including trace metals, solvents, and halogenated hydrocarbons, are reviewed, in terms of milk partition factors, potential infant exposures, and possible infant health effects. In addition to ingestion of a chemical from breast milk, an infant incurs a neonatal body burden of a chemical due to transplacental migration from maternal blood. For trace metals, neonatal blood levels are similar to maternal blood levels. Partition of metals to milk is less efficient, but nevertheless can contribute significantly to an infant's body burden. For lipid-soluble pesticide residues and halogenated biphenyls, neonatal body burden is much less than that of the mother, but transfer to milk is efficient, due to the high proportion of milk fat. It is suggested that potential organic mercury toxicity can be estimated from concentration in maternal blood or milk. For other chemicals, available data are not sufficient to evaluate short- or long-term health effects. However, for many halogenated hydrocarbons, concentrations in normal human milk would permit infant exposure above guidelines for allowable daily intake set by the World Health organization.

Wolff, M.S.

1983-01-01

418

Organo derivatives of zirconium-phosphate  

SciTech Connect

A series of alkyl and aryl diphosphonic acids in which the size of the alkyl and aryl group is systematically varied has been synthesized. The corresponding zirconium diphosphonates, mixed-component pillared zirconium phosphite/phosphate diphosphonates, mixed-component non-pillared zirconium phosphite phenyl phosphonates and their sulphonated derivatives have been prepared by various synthetic methods. An extensive study of the preparative conditions of these synthetic methods has been carried out. These compounds were characterized by X-ray diffraction, TG analysis, elemental analysis, IR spectroscopy, titration curves, surface area measurement, pore size distribution, solid state NMR and electron microscopic study. Their various possible applications were also investigated. Since the organic zirconium exchangers readily form membranes which quantitatively adsorb (Ru(bipy)/sub 3/)/sup 2 +/ (bipsy = bipsyridyl) and methyl viologen, they serve as a convenient support for photochemically induced charge transfer reactions. The charge-transfer photochemical reaction between (Ru(bipy)/sub 3/)/sup 2 +/ and (Co(NH/sub 3/)/sub 5/ Cl)/sup 2 +/ in layered film of zirconium sulphophosphonate undergoes a limited cyclic photolytic water splitting reaction was described.

Yang, C.Y.

1986-01-01

419

Synthesis and pharmacological evaluation of some new naphthol derived aryloxy derivatives as cognition enhancers  

Microsoft Academic Search

The present research was designed to describe the synthesis of a series of some 1-naphthol derivatives with their antiamnesic\\u000a activity using mice as the animal model and piracetam as the reference drug. All the synthesized compounds were characterized\\u000a by spectroscopic techniques, elemental analysis and were screened for their efficacy as cognition enhancers by elevated plus\\u000a maze test and acetylcholinestrase inhibitory

Poonam Piplani; Ruchi Malik; Bhavneet Kaur; Anuradha Kaplish

420

Two new 5-hydroxy-2-pyrone derivatives isolated from a marine-derived fungus Aspergillus flavus.  

PubMed

Two new compounds, 4-(hydroxymethyl)-5-hydroxy-2H-pyran-2-one (1) and (5-hydroxy-2-oxo-2H-pyran-4-yl) methyl acetate (2), have been isolated from a marine-derived fungus Aspergillus flavus. Their structures were determined by spectroscopic data. Compound 1 induced the production of cAMP on GPR12 transfected CHO and HEK293 cells in a dose-dependent manner, which indicated 1 might be a possible ligand for GPR12. PMID:18503205

Lin, Aiqun; Lu, Xiaoming; Fang, Yuchun; Zhu, Tianjiao; Gu, Qianqun; Zhu, Weiming

2008-04-01

421

Two New 5Hydroxy2-pyrone Derivatives Isolated from a Marine-derived Fungus Aspergillus flavus  

Microsoft Academic Search

Two new compounds, 4-(hydroxymethyl)-5-hydroxy-2H-pyran-2-one (1) and (5-hydroxy-2-oxo-2H-pyran-4-yl) methyl acetate (2), have been isolated from a marine-derived fungus Aspergillus flavus. Their structures were determined by spectroscopic data. Compound 1 induced the production of cAMP on GPR12 transfected CHO and HEK293 cells in a dose-dependent manner, which indicated 1 might be a possible ligand for GPR12.

Aiqun Lin; Xiaoming Lu; Yuchun Fang; Tianjiao Zhu; Qianqun Gu; Weiming Zhu; W. Zhu

2008-01-01

422

Mechanical Derivation of Functional Myotubes from Adipose-Derived Stem Cells  

PubMed Central

Though reduced serum or myoblast co-culture alone can differentiate adipose-derived stem cells (ASCs) into mesenchymal lineages, efficiency is usually not sufficient to restore function in vivo. Often when injected into fibrotic muscle, their differentiation may be misdirected by the now stiffened tissue. Here ASCs are shown to not just simply reflect the qualitative stiffness sensitivity of bone-marrow-derived stem cells (BMSCs) but to exceed BMSC myogenic capacity, expressing the appropriate temporal sequence of muscle transcriptional regulators on muscle-mimicking extracellular matrix in a tension and focal adhesion-dependent manner. ASCs formed multi-nucleated myotubes with a continuous cytoskeleton that was not due to misdirected cell division; microtubule depolymerization severed myotubes, but after washout, ASCs re-fused at a rate similar to pretreated values. BMSCs never underwent stiffness-mediated fusion. ASC-derived myotubes, when replated onto non-permissive stiff matrix, maintain their fused state. Together these data imply enhanced mechanosensitivity for ASCs, making them a better therapeutic cell source for fibrotic muscle.

Choi, Yu Suk; Vincent, Ludovic G.; Lee, Andrew R.; Dobke, Marek K.; Engler, Adam J.

2011-01-01

423

Paracrine Interaction between Adipose-Derived Stromal Cells and Cranial Suture-Derived Mesenchymal Cells  

PubMed Central

Introduction Adipose derived stromal cells (ASCs) are a potential cell source for the successful healing of skeletal defects. In this study we sought to investigate the potential for cranial suture-derived mesenchymal cells (SMCs) to promote the osteogenic differentiation of ASCs. Various reports have previously examined the unique in vitro attributes of SMCs; this study sought to extend those findings. Methods SMCs were isolated from wild-type mice (N=30) from both the fusing posterofrontal (PF) and patent sagittal (SAG) sutures. Cells were placed in transwell inserts with human ASCs (N=5 patients) with osteogenic differentiation medium with or without rNoggin (10-400 ng/ml). Specific gene expression of osteogenic markers and Hedgehog pathway were assayed; standard osteogenic assays (alkaline phosphatase and Alizarin red staining) were performed. All assays were performed in triplicate. Results Both PF and SAG SMCs induced osteogenic differentiation of ASCs (*p<0.05). PF SMCs induced ASC-osteogenesis to a greater degree than SAG SMCs (*p<0.05). This was accompanied by an increase in BMP expression (*p<0.05). Finally, rNoggin mitigated the pro-osteogenic effects of co-culture accompanied by a reduction in Hedgehog signaling (*p<0.05). Conclusions SMCs secrete paracrine factors that induce osteodifferentiation of multipotent stromal cells (hASCs). Cells derived from the fusing PF suture do this to a significantly greater degree than cells from the patent SAG suture. Enhanced BMP and Hedgehog signaling may underlie this paracrine effect.

James, Aaron W.; Levi, Benjamin; Commons, George W.; Glotzbach, Jason; Longaker, Michael T.

2010-01-01

424

Derivative encoding for parallel magnetic resonance imaging a  

PubMed Central

Purpose: To introduce a linear shift-invariant relationship between the partial derivatives of k space signals acquired using multichannel receive coils and to demonstrate that k space derivatives can be used for image unwrapping.Methods: Fourier transform of k space derivatives contains information on the spatial origins of aliased pixels; therefore, images can be reconstructed by k space derivatives. Fully sampled phantom and brain images acquired at 3 T using a standard eight channel receive coil were used to validate the k space derivatives theorem by unwrapping aliased images.Results: Derivative encoding leads to new methods for parallel imaging reconstruction in both k space and image domains. Noise amplification in sensitivity encoding image reconstruction, which is considered to produce the optimal SNR, can be further reduced using k space derivative encoding without making any assumptions on the characteristics of the images to be reconstructed.Conclusions: This work demonstrated that the partial derivative of the k space signal acquired from one coil with respect to one direction can be expressed as a sum of partial derivatives of signals from multiple coils with respect to the perpendicular k space direction(s). This relationship between the partial derivatives of k space signals is linear and shift-invariant in the Cartesian coordinate system.

Shen, Jun

2011-01-01

425

Intracellular pigment epithelium-derived factor contributes to triglyceride degradation.  

PubMed

Pigment epithelium-derived factor is well known as a secreted glycoprotein with multiple functions, such as anti-angiogenic, neuroprotective and anti-tumor activities. However, its intracellular role remains unknown. The present study was performed to demonstrate the intracellular function of pigment epithelium-derived factor on triglyceride degradation. Hepatic pigment epithelium-derived factor levels increased at the early stage and subsequently decreased after 16 weeks in high-fat-diet-fed mice compared to those in chow-fed mice. Similarly, oleic acid led to long-term downregulation of pigment epithelium-derived factor in HepG2 cells. Endogenous pigment epithelium-derived factor was an intracellular protein with cytoplasmic distribution in hepatocytes by immunostaining. Exogenous FITC-labeled pigment epithelium-derived factor could be absorbed into hepatocytes. Both signal peptide deletion and full-length pigment epithelium-derived factor transfection HeLa cells and hepatocytes promoted triglyceride degradation. Intracellular pigment epithelium-derived factor co-immunoprecipitated with adipose triglyceride lipase and promoted triglyceride degradation in an adipose triglyceride lipase-dependent manner. Additionally, pigment epithelium-derived factor bound to the C-terminal of adipose triglyceride lipase (aa268-504) and adipose triglyceride lipase-G0/G1 switch gene-2 complex simultaneously, which facilitated adipose triglyceride lipase-G0/G1 switch gene-2 translocation onto lipid droplet using bimolecular fluorescence complementation assay. Moreover, knockdown of endogenous pigment epithelium-derived factor in hepatocytes diminished triglyceride degradation. Taken together, these results indicate that hepatic pigment epithelium-derived factor was decreased in obese mice accompanied with hepatic steatosis. Intracellular pigment epithelium-derived factor binds to and facilitates adipose triglyceride lipase translocation onto lipid droplet, which promotes triglyceride degradation. These findings suggest that a decreased level of hepatic pigment epithelium-derived factor may contribute to hepatic steatosis in obesity. PMID:23886488

Dai, Zhiyu; Zhou, Ti; Li, Cen; Qi, Weiwei; Mao, Yuling; Lu, Juling; Yao, Yachao; Li, Lei; Zhang, Ting; Hong, Honghai; Li, Shuai; Cai, Weibin; Yang, Zhonghan; Ma, Jianxing; Yang, Xia; Gao, Guoquan

2013-07-22

426

Derivation of the high field semiconductor equations  

NASA Astrophysics Data System (ADS)

Electron and hole densities evolve in x-z phase space according to Boltzmann equations. When the mean free path of the particles is short and electric force on the particles is weak, a well-known expansion can be used to solve the Boltzmann equation. This asymptotic solution shows that the spatial density of electrons and holes evolves according to diffusion-drift equations. As devices become smaller, electric fields become stronger, which renders the basic semiconductor equations increasingly inaccurate. To remedy this problem, we use singular perturbation techniques to obtain a new asymptotic expansion for the Boltzmann equation. Like the Hilbert expansion, the new expansion requires the mean free path to be short compared to all macroscopic length scales. However, it does not require the electric forces to be weak. The new expansion shows that spatial densities obey diffusion-drift equations as before, but the diffusivity D and mobility (mu) turn out to be nonlinear functions of the electric field. In particular, our analysis determines the field-dependent mobilities, mu(E), and diffusivities, D(E), directly from the scattering operator. By carrying out this asymptotic expansion to higher order, we obtain the high frequency corrections to the drift velocity and diffusivity, and also the corrections due to gradients in the electric field. Remarkably, we find that Einsteins's relation is still satisfied, even with these corrections. The new diffusion-drift equations, together with Poissons' equation for the electric field, form the high-field semiconductor equations, which can be expected to be accurate regardless of the strength of the electric fields within the semiconductor. In addition, our analysis determines the entire momentum distribution of the particles, so we derive a very accurate first moment model for semiconductors by substituting the asymptotically-correct distribution back into the Boltzmann equation and taking moments.

Hagan, P. S.; Cox, R. W.; Wagner, B. A.

427

Deriving Motor Primitives Through Action Segmentation  

PubMed Central

The purpose of the present experiment is to further understand the effect of levels of processing (top-down vs. bottom-up) on the perception of movement kinematics and primitives for grasping actions in order to gain insight into possible primitives used by the mirror system. In the present study, we investigated the potential of identifying such primitives using an action segmentation task. Specifically, we investigated whether or not segmentation was driven primarily by the kinematics of the action, as opposed to high-level top-down information about the action and the object used in the action. Participants in the experiment were shown 12 point-light movies of object-centered hand/arm actions that were either presented in their canonical orientation together with the object in question (top-down condition) or upside down (inverted) without information about the object (bottom-up condition). The results show that (1) despite impaired high-level action recognition for the inverted actions participants were able to reliably segment the actions according to lower-level kinematic variables, (2) segmentation behavior in both groups was significantly related to the kinematic variables of change in direction, velocity, and acceleration of the wrist (thumb and finger tips) for most of the included actions. This indicates that top-down activation of an action representation leads to similar segmentation behavior for hand/arm actions compared to bottom-up, or local, visual processing when performing a fairly unconstrained segmentation task. Motor primitives as parts of more complex actions may therefore be reliably derived through visual segmentation based on movement kinematics.

Hemeren, Paul E.; Thill, Serge

2011-01-01

428

Oxidative stress induced by a dihydropyrazine derivative.  

PubMed

The Maillard reaction contributes to the complications of diabetes and normal aging. Dihydropyrazines (DHPs), which are produced during the Maillard reaction, generate radicals and possess DNA strand-cleaving activities in vitro. In the present study, we evaluated the genotoxic and cytotoxic potentials of a DHP derivative, cyclohexyl-DHP, which is obtained as a mixture of two isomers, 2,3,5,6,7,8-hexahydroquinoxaline (endo-type) and 1,2,3,5,6,7-hexahydroquinoxaline (exo-type), fused with a cyclohexyl ring. Cyclohexyl-DHP caused DNA strand breaks in plasmid pUC18, especially in the presence of Cu(2+). By using Escherichia coli mutant strains, we observed that cyclohexyl-DHP exposure strongly reduced the survival rate of a cytosolic sodium dodecyl sulfate (SOD)-deficient strain (sodA sodB), significantly reduced the survival rates of DNA repair-deficient strains (recA and uvrB) and mildly reduced the survival rate of a catalase-deficient strain (katE katG) compared with the survival rate of the wild-type strain. Addition of Cu(2+) enhanced the cell killing ability of cyclohexyl-DHP. The frequency of mutations induced by cyclohexyl-DHP increased dose-dependently in the sodA sodB strain. Assays with the highly water-soluble tetrazolium salt WST-1 revealed that cyclohexyl-DHP strongly generated superoxide anions. Moreover, cyclohexyl-DHP elevated the protein carbonyl levels in E. coli. These findings indicate that cyclohexyl-DHP could potentially generate superoxide anions, and cause not only breakage of chromosomal DNA leading to mutagenic lesions but also induce damage to cellular proteins. PMID:19182373

Takechi, Shinji; Nakahara, Kazuhide; Adachi, Masaru; Yamaguchi, Tadatoshi

2009-02-01

429

Derivation of Practical Kedem - Katchalsky Equations for Membrane Substance Transport  

NASA Astrophysics Data System (ADS)

The following paper includes a derivation of practical Kedem-Katchalsky (K-K) equations for the volume flow J? and the solute flow Js for non-electrolytes. This derivation makes the equations clearer and consequently their interpretation also becomes easier. The equations have been derived on the basis of the analysis of the membrane transport generated by simultaneous action of two thermodynamic stimuli: the hydrostatic pressure difference ?p and the osmotic pressure difference ??. Furthermore, the derivation of the solute permeability coefficient ?, which results from K-K equations, is also presented in this paper. The formulas for coefficients characterizing membrane permeability, ?d and ?k, as well as their derivation and physical interpretation are also presented below. Finally, a formula for the membrane coefficient LD, which represents a diffusional mobility, is derived.

Jarzy?ska, M.; Pietruszka, M.

2008-09-01

430

Pyrazole derivatives as antitumor, anti-inflammatory and antibacterial agents.  

PubMed

Within the past years, many researches on the synthesis, structure-activity relationships (SAR), antitumor, antiinflammatory and anti-bacterial activities of the pyrazole derivatives have been reported. Several pyrazole derivatives possess important pharmacological activities and they have been proved useful materials in drug research. Pyrazole derivatives play an important role in antitumor agents because of their good inhibitory activity against BRAF(V600E), EGFR, telomerase, ROS Receptor Tyrosine Kinase and Aurora-A kinase. In addition, pyrazole derivatives also show good antiinflammatory and anti-bacterial activities. In this review, the bioactivities of the pyrazole derivatives mentioned above will be summarized in detail. We sincerely hope that increasing knowledge of the SAR and cellular processes underlying the bioactivity of pyrazole derivatives will be beneficial to the rational design of new generation of small molecule drugs. PMID:23937232

Liu, Jia-Jia; Zhao, Meng-Yue; Zhang, Xin; Zhao, Xin; Zhu, Hai-Liang

2013-11-01

431

Contracted auxiliary Gaussian basis integral and derivative evaluation  

NASA Astrophysics Data System (ADS)

The rapid evaluation of two-center Coulomb and overlap integrals between contracted auxiliary solid harmonic Gaussian functions is examined. Integral expressions are derived from the application of Hobson's theorem and Dunlap's product and differentiation rules of the spherical tensor gradient operator. It is shown that inclusion of the primitive normalization constants greatly simplifies the calculation of contracted functions corresponding to a Gaussian multipole expansion of a diffuse charge density. Derivative expressions are presented and it is shown that chain rules are avoided by expressing the derivatives as a linear combination of auxiliary integrals involving no more than five terms. Calculation of integrals and derivatives requires the contraction of a single vector corresponding to the monopolar result and its scalar derivatives. Implementation of the method is discussed and comparison is made with a Cartesian Gaussian-based method. The current method is superior for the evaluation of both integrals and derivatives using either primitive or contracted functions.

Giese, Timothy J.; York, Darrin M.

2008-02-01

432

The Schwarzian derivative, conformal connections, and Möbius structures  

Microsoft Academic Search

Despite its well established role in complex analysis, the Schwarzian derivative remains somewhat mysterious. It is not a derivative, exactly, but what is it? The paper [OS1] takes up that question, introducing a generalized Schwarzian tensor S(f) when f is a conformal mapping between Riemannian manifolds. Upon closer examination, S(f) seems to derive not so much from the Riemannian metrics

Brad Osgood; Dennis Stowe

1998-01-01

433

Higher derivative terms from threebranes in F theory  

Microsoft Academic Search

The computation of higher derivative corrections to the low energy effective actions of N=2 gauge theories is considered. In particular, higher derivative corrections are computed for four dimensional N=2 super Yang-Mills theory with gauge group SU(2) and Nf=4 hypermultiplets in the fundamental representation. The four derivative terms computed in an approach which realizes the gauge theory as the world volume

Robert de Mello Koch; Radu Tatar

1999-01-01

434

Automatic evaluation of first- and higher-derivative vectors  

SciTech Connect

The numerical analysis of parameter-dependent nonlinear systems almost always involves first-derivative matrices and often also requires the evaluation of higher derivatives along certain singular directions. It is shown here how these selected derivative values can be obtained without differencing and at a reasonable cost under the realistic assumption that the nonlinear system is given in the form of a computer program for its evaluation. 14 refs.

Griewank, A.

1990-01-01

435

Synthesis of Hydroxyl Radical Scavengers from Benzalacetone and its Derivatives  

Microsoft Academic Search

Synthesis of hydroxyl radical scavengers from benzalacetone and its derivatives has been done. Benzalacetone synthesis was done by crossed aldol condensation between benzaldehyde and acetone with 1:1 mol ratio, while dibenzalacetone in 2:1 mol ratio. Benzalacetone derivatives were synthesized by replacing benzaldehyde with its derivatives, i.e. p-anisaldehyde, veratraldehyde and cinnamaldehyde. The compounds that were active as radical scavengers based on

Sri Handayani; Indyah Sulistyo Arty

2008-01-01

436

Synthesis and antifungal activity of organofluorine derivatives of levorin  

Microsoft Academic Search

Reactions of the polyene macrolide antibiotic levorin with organofluorine alcohols lead to the formation of organofluorine\\u000a esters. Two organofluorine derivatives of levorin have been synthesized and their physicochemical and biological properties\\u000a have been studied. These derivatives show high antifungal activity against a large number of test cultures. The acute toxicity\\u000a (LD50) of levorin derivatives was about half that of the

V. V. Belakhov; Yu. D. Shenin; R. A. Araviisky

2007-01-01

437

Placental-Derived Stem Cells: Potential Clinical Applications  

Microsoft Academic Search

\\u000a Placental-derived stem cells are easily accessible and do not have many of the limitations of embryonic stem cells and their\\u000a derivatives for use in clinical trials. Preclinical animal studies using amnion and, more recently, human amnion epithelial\\u000a cells (hAECs) have provided evidence of many exciting potential clinical applications. We have characterized hAECs derived\\u000a from term gestational tissues and investigated their

Sean Murphy; Euan Wallace; Graham Jenkin

438

A Continuous Derivative for Real-Valued Functions  

Microsoft Academic Search

Summary. We develop a notion of derivative of a real-valued function on a Banach space, called the L-derivative, which is constructed by introducing a generalization of Lipschitz constant of a map. As with the Clarke gradient, the values of the L-derivative of a function are nonempty, weak,* compact, and convex subsets of the dual of the Banach space. The Lderivative,

Abbas Edalat

439

Synthesis and biological activity of 5-aza-ellipticine derivatives  

PubMed Central

Novel 5-aza-ellipticine derivatives were synthesized and tested as antitumor agents. The new compounds were prepared more readily than the analogous ellipticine derivatives, which are known to be potent anti-tumor agents Although the novel 5-aza-ellipticine derivatives are not as biologically active as their corresponding ellipticine analogues, the new compounds represent a new, readily accessible class of heteroaromatic catalytic inhibitors of topoisomerase II and possible anti-tumor agents.

Moody, Deborah L.; Dyba, Marcin; Kosakowska-Cholody, Teresa; Tarasova, Nadya I.; Michejda, Christopher J.

2007-01-01

440

Criticality safety benchmark experiments derived from ANL ZPR assemblies.  

SciTech Connect

Numerous criticality safety benchmarks have been, and continue to be, developed from experiments performed on Argonne National Laboratory's plate-type fast critical assemblies. The nature and scope of assemblies suitable for deriving these benchmarks are discussed. The benchmark derivation process, including full treatment of all significant uncertainties, is explained. Calculational results are presented that support the small uncertainty assigned to the key derivation step in which complex geometric detail is removed.

Schaefer, R. W.; Lell, R. M.; McKnight, R. D.

2003-09-01

441

Thrombolytic agents and thienopyridine derivatives in acute stroke  

US Patent & Trademark Office Database

Methods and products are provided for treating thromboembolic stroke. A method involves the administration of a thienopyridine derivative in combination with a thrombolytic agent to a patient suffering from thromboembolic stroke. Preferably the thienopyridine derivative is ticlopidine and the thrombolytic agent is tPA. The method also involves the administration of a thrombolytic agent to a subject who already has circulating plasma levels of a thienopyridine derivative. The product is a pharmaceutical preparation of a thienopyridine derivative and a thrombolytic agent and a pharmaceutically acceptable carrier.

1999-08-31

442

Derivatives of the polarization propagator including orbital relaxation effects.  

PubMed

In this article, we relate derivatives of the polarization propagator used in many-body theory to the nonlinear (quadratic) polarization propagator, and we relate derivatives of the quadratic polarization propagator to the nonlinear propagator of the next higher order, the cubic polarization propagator. We restrict the analysis to differentiation with respect to parameters eta for which the derivative of the Hamiltonian can be written as a sum of one-electron operators. Geometrical derivatives are obtained by specializing to the parameter eta to the alpha coordinate of nucleus I. We treat orbital relaxation explicitly by allowing for the eta dependence of creation and annihilation operators in the propagators. This treatment entails an extension of the geometrical derivative relations among response functions proven by Olsen and Jorgensen [J. Chem. Phys. 82, 3235 (1985)], because the propagator derivatives may involve changes in the one-electron orbitals that do not appear in the susceptibility derivatives. These results underlie the relations between Raman intensities and electric-field shielding tensors, which have been explained in terms of nonlocal polarizability and hyperpolarizability densities. The results suggest an alternative computational route to geometrical or other derivatives of both linear- and nonlinear-response functions: these derivatives can be evaluated without numerical differentiation, directly from the propagator of the next higher order. PMID:17552752

Tisko, Edmund L; Hunt, Katharine L C

2007-05-28

443

40 CFR 721.10045 - Diazotized substituted heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel...  

Code of Federal Regulations, 2010 CFR

...heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel complex...heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel complex...heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel...

2010-07-01

444

40 CFR 721.10045 - Diazotized substituted heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel...  

Code of Federal Regulations, 2010 CFR

...heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel complex...heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel complex...heteromonocycle coupled with naphthalene sulfonic acid derivative, nickel...

2009-07-01

445

Asteroid Thermal Properties Derived from Meteorite Data  

NASA Astrophysics Data System (ADS)

The thermal inertia of an asteroid’s surface determines its response to the various Yarkovsky effects, while its internal thermal diffusivity controls its thermal evolution. Each quantity is a function of the material’s thermal conductivity, heat capacity, and density. Over the past ten years we have conducted a detailed survey measuring density in meteorites and are currently in the early stages of similar surveys for thermal conductivity and heat capacity. While various meteorite types differ in small but significant ways, for asteroid studies typical average values of these quantities can be estimated to within about 10%. (Metallic asteroids would have significantly different behavior.) The most important variable controlling density and thermal conductivity is porosity, P, while heat capacity is a strong function of temperature, T. Most stony meteorite densities are within 10% of 3500*(1-P) (SI units); basaltic and volatile rich meteorites are 10% to 30% less dense. Thermal conductivity in the temperature range of interest in the asteroid belt is nearly constant with temperature but varies strongly with porosity; assuming the trend seen for meteorite porosities up to 25% can be extrapolated to higher porosities, with zero conductivity at 100% porosity, a typical conductivity (for porosities greater than 2%) can be approximated by k = 0.11/P - 0.11 (SI units). Heat capacity ranges from under 250 J/kgK at 100 K to over 600 J/kgK at 250 K; over these temperatures this variation can be fitted by a quadratic in T. From these formulae we can derive representative values for thermal inertia and diffusivity and see how they vary as a function of porosity and temperature values appropriate for most asteroids. The greatest variation is with porosity. Thermal diffusivity drops by nearly two orders of magnitude from 0 to 20% porosity, more slowly at higher porosities. Thermal inertia (at 200K) varies from 3000 (SI units) near zero porosity down to 3 as porosity approaches 100%; 10% porosity has a thermal inertia near 1000 while 90% porous is about 60. Literature asteroid thermal inertias range from as high as 1000 to below 30; asteroid thermal inertias below 100 demand an extremely porous (>80%) surface.

Consolmagno, Guy; Macke, R. J.; Britt, D. T.

2013-10-01

446

Rigorous derivation of electromagnetic self-force  

SciTech Connect

During the past century, there has been considerable discussion and analysis of the motion of a point charge in an external electromagnetic field in special relativity, taking into account 'self-force' effects due to the particle's own electromagnetic field. We analyze the issue of 'particle motion' in classical electromagnetism in a rigorous and systematic way by considering a one-parameter family of solutions to the coupled Maxwell and matter equations corresponding to having a body whose charge-current density J{sup a}({lambda}) and stress-energy tensor T{sub ab}({lambda}) scale to zero size in an asymptotically self-similar manner about a worldline {gamma} as {lambda}{yields}0. In this limit, the charge, q, and total mass, m, of the body go to zero, and q/m goes to a well-defined limit. The Maxwell field F{sub ab}({lambda}) is assumed to be the retarded solution associated with J{sup a}({lambda}) plus a homogeneous solution (the 'external field') that varies smoothly with {lambda}. We prove that the worldline {gamma} must be a solution to the Lorentz force equations of motion in the external field F{sub ab}({lambda}=0). We then obtain self-force, dipole forces, and spin force as first-order perturbative corrections to the center-of-mass motion of the body. We believe that this is the first rigorous derivation of the complete first-order correction to Lorentz force motion. We also address the issue of obtaining a self-consistent perturbative equation of motion associated with our perturbative result, and argue that the self-force equations of motion that have previously been written down in conjunction with the 'reduction of order' procedure should provide accurate equations of motion for a sufficiently small charged body with negligible dipole moments and spin. (There is no corresponding justification for the non-reduced-order equations.) We restrict consideration in this paper to classical electrodynamics in flat spacetime, but there should be no difficulty in extending our results to the motion of a charged body in an arbitrary globally hyperbolic curved spacetime.

Gralla, Samuel E.; Harte, Abraham I.; Wald, Robert M. [Enrico Fermi Institute and Department of Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637 (United States)

2009-07-15

447

Nanoscale Reinforced, Polymer Derived Ceramic Matrix Coatings  

SciTech Connect

The goal of this project was to explore and develop a novel class of nanoscale reinforced ceramic coatings for high temperature (600-1000 C) corrosion protection of metallic components in a coal-fired environment. It was focused on developing coatings that are easy to process and low cost. The approach was to use high-yield preceramic polymers loaded with nano-size fillers. The complex interplay of the particles in the polymer, their role in controlling shrinkage and phase evolution during thermal treatment, resulting densification and microstructural evolution, mechanical properties and effectiveness as corrosion protection coatings were investigated. Fe-and Ni-based alloys currently used in coal-fired environments do not possess the requisite corrosion and oxidation resistance for next generation of advanced power systems. One example of this is the power plants that use ultra supercritical steam as the working fluid. The increase in thermal efficiency of the plant and decrease in pollutant emissions are only possible by changing the properties of steam from supercritical to ultra supercritical. However, the conditions, 650 C and 34.5 MPa, are too severe and result in higher rate of corrosion due to higher metal temperatures. Coating the metallic components with ceramics that are resistant to corrosion, oxidation and erosion, is an economical and immediate solution to this problem. Good high temperature corrosion protection ceramic coatings for metallic structures must have a set of properties that are difficult to achieve using established processing techniques. The required properties include ease of coating complex shapes, low processing temperatures, thermal expansion match with metallic structures and good mechanical and chemical properties. Nanoscale reinforced composite coatings in which the matrix is derived from preceramic polymers have the potential to meet these requirements. The research was focused on developing suitable material systems and processing techniques for these coatings. In addition, we investigated the effect of microstructure on the mechanical properties and oxidation protection ability of the coatings. Coatings were developed to provide oxidation protection to both ferritic and austentic alloys and Ni-based alloys. The coatings that we developed are based on low viscosity pre-ceramic polymers. Thus they can be easily applied to any shape by using a variety of techniques including dip-coating, spray-coating and painting. The polymers are loaded with a variety of nanoparticles. The nanoparticles have two primary roles: control of the final composition and phases (and hence the properties); and control of the shrinkage during thermal decomposition of the polymer. Thus the selection of the nanoparticles was the most critical aspect of this project. Based on the results of the processing studies, the performance of selected coatings in oxidizing conditions (both static and cyclic) was investigated.

Rajendra Bordia

2009-07-31

448

Synthesis of novel steroid derivatives derived from dehydroepiandrosterone as potential anticancer agents.  

PubMed

A series of dehydroepiandrosterone derivatives containing dihydrazone unit was synthesized via a convenient condensation procedure, and which were evaluated for their potential anticancer activities. The preliminary assays indicated that some of the newly synthesized compounds exhibited good antitumor activities against human hepatocellular liver carcinoma (HepG2), heptoma (Huh-7), gastric cancer (BGC-823) and breast adenocarcinoma (MCF-7) cell lines compared with 5-fluorouracil (5-FU), which might be considered as promising lead scaffold for further design and synthesis of potential anticancer agents. PMID:23547874

Ke, Shaoyong; Wei, Yanhong; Shi, Liqiao; Yang, Qingyu; Yang, Ziwen

2013-10-01

449

Derivatives of molecular electromagnetic properties using nonlocal susceptibility densities  

NASA Astrophysics Data System (ADS)

This thesis presents three analytic derivative relationships. The underlying concept of these three relationships is connecting the change of a molecular property to other well-defined molecular properties. The foundation of this work lies in nonlocal polarizability density theory. The nonlocal polarizability density characterizes the polarization at one point in a molecule due to its reaction with an electric field at another point in the molecule. In the first part, the derivative of the electronic hyperpolarizability with respect to a Cartesian nuclear coordinate is related to the nonlocal second hyperpolarizability density, the nuclear charge and the dipole propagator. The derivation uses the derivatives of the wavefunctions and operators that comprise the six- term hyperpolarizability. These derivatives, which are also derived, are substituted into the hyperpolarizability to yield a sixty-term expression. The initial result is manipulated algebraically in a nontrivial way to yield the equality. A brief review of hyper-Raman scattering theory is given. Recent applications of hyper-Raman scattering are considered. In the second part a new expression for the derivative of the polarization propagator with respect to an arbitrary coordinate is derived in terms of the quadratic polarization propagator and a sum of polarization propagators. The derivation involves calculating the derivative of a creation and annihilation operator pair with respect to an arbitrary parameter. Then the propagator derivative is calculated via the derivatives of many-electron wavefunctions. Past work calculating the derivatives of molecular properties using polarization propagator techniques is briefly reviewed. The third part concerns finding an expression for the derivative of the electronic magnetic moment with respect to nuclear momentum and its relationship to a nonlocal magnetizability density. The magnetizability density has a structure similar to the chemical shift. The relationship is found by considering the magnetic field produced by a moving nucleus as a perturbation on the electronic structure. The ground state wavefunctions are corrected to first order in perturbation theory using the nuclear magnetic field as the perturbation. The corrected wavefunctions are used to calculate the expectation value of the magnetic moment. When the derivative of this expectation value is taken with respect to nuclear momentum, its relationship with the nonlocal chemical shift density is uncovered. The result is correct when adiabatic wavefunctions that go beyond the Born- Oppenheimer approximation are used. The physical content of the equation is interpreted as a description of intramolecular magnetic response. Other possible paths to a complete susceptibility theory are considered. One path involves substitution of 4- currents into the definition of the nonlocal polarizability density. Other paths arise from an initial consideration of the relativistic Dirac equation and subsequent analysis using the Gordon decomposition and the Foldy-Wouthuysen transformation.

Tisko, Edmund Leo

450

Diketopiperazine Derivatives from the Marine-Derived Actinomycete Streptomyces sp. FXJ7.328  

PubMed Central

Five new diketopiperazine derivatives, (3Z,6E)-1-N-methyl-3-benzylidene-6-(2S-methyl-3-hydroxypropylidene)piperazine-2,5-dione (1), (3Z,6E)-1-N-methyl-3-benzylidene-6-(2R-methyl-3-hydroxypropylidene)piperazine-2,5-dione (2), (3Z,6Z)-3-(4-hydroxybenzylidene)-6-isobutylidenepiperazine-2,5-dione (3), (3Z,6Z)-3-((1H-imidazol-5-yl)-methylene)-6-isobutylidenepiperazine-2,5-dione (4), and (3Z,6S)-3-benzylidene-6-(2S-but-2-yl)piperazine-2,5-dione (5), were isolated from the marine-derived actinomycete Streptomyces sp. FXJ7.328. The structures of 1–5 were determined by spectroscopic analysis, CD exciton chirality, the modified Mosher’s, Marfey’s and the C3 Marfey’s methods. Compound 3 showed modest antivirus activity against influenza A (H1N1) virus with an IC50 value of 41.5 ± 4.5 ?M. In addition, compound 6 and 7 displayed potent anti-H1N1 activity with IC50 value of 28.9 ± 2.2 and 6.8 ± 1.5 ?M, respectively. Due to the lack of corresponding data in the literature, the 13C NMR data of (3Z,6S)-3-benzylidene-6-isobutylpiperazine-2,5-dione (6) were also reported here for the first time.

Wang, Pei; Xi, Lijun; Liu, Peipei; Wang, Yi; Wang, Wei; Huang, Ying; Zhu, Weiming

2013-01-01

451

Incubation-derived calcium carbonate equivalence of papermill boiler ashes derived from sludge and wood sources.  

PubMed

The burning of a papermill sludge and wood mixture and landspreading the resulting ash is a potential means of disposal of papermill sludge without the use of valuable landfill space. This study evaluated the effectiveness of ashes derived from a mixture of papermill sludge and wood sources to act as an alternative liming agent. The calcium carbonate equivalence of the material was determined using a 91-day laboratory incubation test with three mineral soils and one organic horizon soil. Application rates of soil-incorporated sludge-ash ranged from 2.30 to 32.2 g per kg soil. Soil pH increased linearly with increasing sludge-ash application rate. The calcium carbonate equivalence of the material varied temporally and the average value ranged from 19% to 28%. The fraction of total P, K and Mg added with the sludge-ash and extracted from the ash-amended soils using an NH4OAc based soil test method were 2.6, 3.8 and 17.6%, respectively. The low soil test extractability of ash-derived plant nutrients suggests that this material would provide only a modest increase in plant available nutrient levels in landspread fields. PMID:15091902

Ohno, T; Erich, M S

1993-01-01

452

Production of Chemical Derivatives from Renewables  

SciTech Connect

The purpose of this Cooperative Research and Development Agreement (CRADA) between Lockheed Martin Energy Research Corp., (LMER), Argonne National Laboratory (ANL), National Renewable Energy Laboratory (NREL), and Battelle Memorial Institute, operator of Pacific Northwest National Laboratory (PNNL), (collectively referred to as the 'Contractor'), and Applied Carbochemicals, Inc. (Participant) was to scale-up from bench results an economically promising and competitive process for the production of chemical derivatives from biologically produced succinic acid. The products that were under consideration for production from the succinic acid platform included 1,4-butanediol, {gamma}y-butyrolactone, 2-pyrrolidinone and N-methyl pyrrolidinone. Preliminary economic analyses indicated that this platform was competitive with the most recent petrochemical routes. The Contractors and participant are hereinafter jointly referred to as the 'Parties.' Research to date in succinic acid fermentation, separation and genetic engineering resulted in a potentially economical process based on the use of an Escherichia coli strain AFP111 with suitable characteristics for the production of succinic acid from glucose. Economic analysis has shown that higher value commodity chemicals can be economically produced from succinic acid based on preliminary laboratory findings and predicted catalytic parameters. At the time, the current need was to provide the necessary laboratory follow-up information to properly optimize, design and operate a pilot scale process. The purpose of the pilot work was to validate the integrated process, assure 'robustness' of the process, define operating conditions, and provide samples for potential customer evaluation. The data from the pilot scale process was used in design and development of a full scale production facility. A new strain, AFP111 (patented), discovered at ANL was tested and developed for process use at the Oak Ridge National Laboratory (ORNL) and ANL. The operability and product formation are attractive for this strain and effort was being directed at process development and optimization. Key to the transition from the fermentative production unit operation to the chemical catalysis is the 'clean-up' of fermentation broth, succinic acid formation from the salt, and succinic acid concentration. These steps are accomplished by a two-stage membrane ED separation process developed at AWL. Although the current process is well developed, possible modifications and optimization may be called for as development work continues in both the fermentation and catalysis areas. Research to date performed at PNNL has demonstrated that succinic acid can be converted to value added chemicals such as 1,4-butanediol, {gamma}-butyrolactone, N-methyl pyrrolidinone, and 2 pyrrolidinone with high conversion and selectivities. Continued research will be performed in catalyst development and reaction condition optimization to move this work from the bench scale to the pilot scale. All development of the process was guided by the NREL technoeconomic model. The model showed that direct aqueous phase catalysis of succinic acid to 1,4-butanediol, {gamma}-butyrolactone, and N-methyl pyrrolidinone provided significant economical advantages in the market, the margin, and the return on capital investment over existing petrochemical processes for production of these compounds. The model also provided the baseline for evaluating current laboratory research. As data from the bench and pilot work were made available the model was modified and appropriate sensitivities ran to determine impact of the process changes and optimization. The report will present the planned CRADA tasks followed by the results. The results section has an overall project summary follwed by more detailed reports from the participants. This is a nonproprietary report; additional proprietary information may be made available subject to acceptance of the appropriate proprietary information agreements.

Davison, Brian; Nghiem, John; Donnelly, Mark; Tsai, Shih-Perng; Frye, John; Landucci, Ron; Griffin, Michael

1996-06-01

453

Characterization of stem rust resistant derivatives of wheat cultivar Amigo  

Microsoft Academic Search

Originally developed for resistance to greenbug derived from Insave rye, Amigo wheat carries two genes for resistance to stem rust. One of these genes is associated with a rye chromosome 1RS segment carrying the Sec-1 protein marker and presumably greenbug resistance. The second gene which is genetically linked to leaf rust resistance is associated with an Agropyron-derived segment. Rust tests

T. T. The; R. B. Gupta; P. L. Dyck; R. Appels; U. Hohmann; R. A. McIntosh

1991-01-01

454

Direct identification offlutter derivatives and aerodynamic admittances ofbridge decks  

Microsoft Academic Search

Flutter derivatives and aerodynamic admittances provide basis ofpredicting the critical wind speed in flutter and buffeting analysis oflong-span cable-supported bridges. In this paper, one popular stochastic system identification technique, covariance- driven stochastic subspace identification (SSI in short), is first presented for estimation of the flutter derivatives and aerodynamic admittances ofbridge decks f rom their random responses in turbulent flow. Numerical

Ming Gu; Xian-Rong Qin

2004-01-01

455

Unique continuation of solutions of differential equations with weighted derivatives  

NASA Astrophysics Data System (ADS)

The paper contains a generalization of Calderon's theorem on the local uniqueness of the solutions of the Cauchy problem for differential equations with weighted derivatives. Anisotropic estimates of Carleman type are obtained. A class of differential equations with weighted derivatives is distinguished in which germs of solutions have unique continuation with respect to part of the variables.

Shananin, N. A.

2000-04-01

456

Unique continuation of solutions of differential equations with weighted derivatives  

SciTech Connect

The paper contains a generalization of Calderon's theorem on the local uniqueness of the solutions of the Cauchy problem for differential equations with weighted derivatives. Anisotropic estimates of Carleman type are obtained. A class of differential equations with weighted derivatives is distinguished in which germs of solutions have unique continuation with respect to part of the variables.

Shananin, N A [Peoples Friendship University of Russia, Moscow (Russian Federation)

2000-04-30

457

Use of Derived Comparison Scores in Clinical Settings.  

ERIC Educational Resources Information Center

Clinicians use a common practice of reporting age or grade equivalent derived scores, but problems of interpretation exist for such scores. This article examines derived comparison score issues and recommends use of scores of relative standing such as percentile ranks or standard scores in contrast to use of developmental scores like age and grade…

Callahan, Joseph P.

458

21 CFR 189.120 - Cobaltous salts and its derivatives.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Cobaltous salts and its derivatives. 189.120 Section...Use as Human Food § 189.120 Cobaltous salts and its derivatives. (a) Cobaltous salts are the chemicals, CoC4 H6 O4 ,...

2013-04-01

459

Recent advance in living anionic polymerization of functionalized styrene derivatives  

Microsoft Academic Search

This review covers recent advance of living anionic polymerization of styrene derivatives with functional groups. Although there have so far been reported several successful systems of living anionic polymerization of functionalized styrene derivatives, most useful functional groups are not amenable to the conditions of living anionic polymerization of styrene. Therefore, we herein present two generalized strategies to be able to

Akira Hirao; Surapich Loykulnant; Takashi Ishizone

2002-01-01

460

Potential of Novel EPO Derivatives in Limb Ischemia.  

PubMed

Erythropoietin (EPO) has tissue-protective properties, but it increases the risk of thromboembolism by raising the haemoglobin concentration. New generation of EPO derivatives is tissue protective without the haematopoietic side effects. Preclinical studies have demonstrated their effectiveness and safety. This paper summarizes the development in EPO derivatives with emphasis on their potential use in critical limb ischaemia. PMID:22462027

Joshi, Dhiraj; Tsui, Janice; Yu, Rebekah; Shiwen, Xu; Selvakumar, Sadasivam; Abraham, David J; Baker, Daryll M

2012-02-22

461

A Numerical Scheme for Dynamic Systems Containing Fractional Derivatives  

Microsoft Academic Search

This paper presents a numerical scheme for dynamic nalysis of mechanical systems subjected to damping forces which are proportional to fractional derivatives of displacements. In this scheme, a fractional differential equation governing the dynamic of a system is transformed into a set of differential equations with no fractional derivative terms. Using Laguerre integral formula, this set is converted to a

Lixia Yuan; Om P. Agrawal

2002-01-01

462

Method of deriving equations of motion for dynamically adjustable gyroscope  

Microsoft Academic Search

The equations of motion for a dynamically adjustable gyroscope are derived in terms of the Lagrange function, of generalized coordinates and velocities and of time, this function assumed to be analytic. The derivation is based on applying an Euler operator to the corresponding Lagrange equation of the second kind and analyzing the Lagrange function as the difference between kinetic energy

M. Y. Shatalov

1984-01-01

463

DERIVATION OF FLUOROMETRIC CHLOROPHYLL AND PHEOPHYTIN EQUATIONS (JOURNAL VERSION)  

EPA Science Inventory

Equations for calculation of chlorophyll a and pheophytin a by fluorometry have been cited in a number of publications. None of them, however, includes the derivation of the equations to substantiate their validity. The derivation is given here to let the user apply the equations...

464

Metal complexation by chitosan and its derivatives: a review  

Microsoft Academic Search

One of the major applications of chitosan and its many derivatives is based on its ability to bind strongly heavy and toxic metal ions. This article reviews the various classes of chitosan derivatives and compares their ion binding abilities under varying conditions, as well as the analytical methods to analyze them, the sorption mechanism, and structural analysis of the metal

A. J Varma; S. V Deshpande; J. F Kennedy

2004-01-01

465

Novel protein kinase C inhibitors: alpha-terthiophene derivatives.  

PubMed

A series of alpha-terthiophene derivatives were prepared and their protein kinase C inhibitory activity were evaluated. The aldehyde derivatives were most potent inhibitors (IC50 < 1 microM). alpha-Terthiophene monoaldehyde was inactive in the inhibitions of protein kinase A, mitogen activated protein kinase and protein tyrosine kinase. PMID:9873605

Kim, D S; Ashendel, C L; Zhou, Q; Chang, C T; Lee, E S; Chang, C J

1998-10-01

466

The use of derivatives in the Spanish mutual fund industry  

Microsoft Academic Search

We study the use of derivatives in the Spanish mutual fund industry. The picture that emerges from our analysis is rather negative. In general, the use of derivatives does not improve the performance of the funds. In only one out of eight categories we find some (very weak and not robust) evidence of superior performance. In most of the cases

José M. Marín; Thomas A. Rangel

2006-01-01

467

Dibenzothiophene derivatives as organic markers of oil pollution  

Microsoft Academic Search

Sulfur compounds as dibenzothiophene derivatives were used as pollution markers in oyster samples after oil spills. By means of high performance glass capillary gas chromatography (GC) fitted with flame photometric detector and mass fragmentography, specific fingerprints of DBT derivatives were obtained in oils and oyster samples. The retention indices of some alkylated DBT (C1 to C4) were measured.

M. P. Friocourt; F. Berthou; D. Picart

1982-01-01

468

Clinical Validation of the ECG-Derived Respiration (EDR) Technique  

Microsoft Academic Search

Summary Respiratory signals may be derived from body surface ECGs by measuring fluctuations in the mean cardiac electrical axis which accompany respiration. Two ongoing clinical studies illustrate the value of the ECG-derived respiration (EDR) technique. The first study demonstrates the feasibility of using Holter recordings as a screening test for sleep apnea. In a sample of 9 patients, diagnoses based

George B. Moody; Roger G. Mark; Marjorie A. Bump; Joseph S. Weinstein; Aaron D. Berman; Joseph E. Mietus; Ary L. Goldberger

1986-01-01

469

A Bioenvironmental Study of Emissions from Refuse Derived Fuel.  

National Technical Information Service (NTIS)

Refuse derived fuel (processed municipal solid waste) was used as a supplement to coal in a utility boiler (80,000 lbs. steam per hour). Furnance emissions were determined from coal, and from 1:1 and 2:1 mixes (by volume) of refuse derived fuel (RDF) and ...

J. W. Jackson

1976-01-01

470

Different anthracycline derivates for reducing cardiotoxicity in cancer patients  

Microsoft Academic Search

Background The use of anthracyclines is limited by the occurrence of cardiotoxicity. In an effort to prevent this cardiotoxicity, different anthracycline derivates have been studied. Objectives To determine the occurrence of cardiotoxicity with the use of different anthracycline derivates in cancer patients. Search strategy We searched The Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library, Issue 2, 2009),

Dalen van E. C; E. M. C. Michiels; H. N. Caron; L. C. M. Kremer

2010-01-01

471

21 CFR 184.1282 - Dill and its derivatives.  

Code of Federal Regulations, 2010 CFR

... 3 2009-04-01 2009-04-01 false Dill and its derivatives. 184.1282 Section 184...Specific Substances Affirmed as GRAS § 184.1282 Dill and its derivatives. (a) Dill (American or European) is the herb and...

2009-04-01

472

21 CFR 184.1282 - Dill and its derivatives.  

Code of Federal Regulations, 2010 CFR

... 3 2010-01-01 2009-04-01 true Dill and its derivatives. 184.1282 Section 184...Specific Substances Affirmed as GRAS § 184.1282 Dill and its derivatives. (a) Dill (American or European) is the herb and...

2010-01-01

473

Method of thermochemically treating silicon carbide fibers derived from polymers  

Microsoft Academic Search

A method is described of thermochemically treating polymeric-derived silicon carbide fiber comprising the step of: annealing a silicon carbide fiber derived from organosilicon polymeric precursors said fiber further including at least: (1) excess carbon and oxygen, (2) excess silicon and oxygen, or (3) nitrogen, at a temperature between 800 C and 1,800 C, thus outgassing from said silicon carbide fiber

J. S. Wallace; B. A. Bender; D. Schrodt

1993-01-01

474

Derivation and Potential Applications of Human Embryonic Stem Cells  

Microsoft Academic Search

Embryonic stem cells are pluripotent cell lines that are derived from the blastocyst-stage early mammalian embryo. These unique cells are characterized by their capacity for prolonged undifferentiated proliferation in culture while maintaining the potential to differentiate into derivatives of all three germ layers. During in vitro differentiation, embryonic stem cells can develop into specialized somatic cells, including cardiomyocytes, and have

Lior Gepstein; Roberto Bolli

2010-01-01

475

New bactericide derived from Isatin for treating oilfield reinjection water  

PubMed Central

Isatin, an extract from Strobilanthes cusia (Nees) Kuntze, was the base for synthesizing derivatives that were screened for antibacterial activity against oilfield water-borne bacteria. The bacterial groups are sulfate reducing, iron and total. The derivatives were characterized by spectrums and they showed good to moderate activity against sulfate reducing bacteria.

2012-01-01

476

Toxicity of Benzotriazole and Benzotriazole Derivatives to Three Aquatic Species  

Microsoft Academic Search

Benzotriazole and its derivatives comprise an important class of corrosion inhibitors, typically used as trace additives in industrial chemical mixtures such as coolants, deicers, surface coatings, cutting fluids, and hydraulic fluids. Recent studies have shown that benzotriazole derivatives are a major component of aircraft deicing fluids (ADFs) responsible for toxicity to bacteria (Microtox®). Our current research compared the toxicity of

David A Pillard; Jeffrey S Cornell; Doree L DuFresne; Mark T Hernandez

2001-01-01

477

Regioselective Enzymatic Carboxylation of Phenols and Hydroxystyrene Derivatives  

PubMed Central

The enzymatic carboxylation of phenol and styrene derivatives using (de)carboxylases in carbonate buffer proceeded in a highly regioselective fashion: Benzoic acid (de)carboxylases selectively formed o-hydroxybenzoic acid derivatives, phenolic acid (de)carboxylases selectively acted at the ?-carbon atom of styrenes forming (E)-cinnamic acids.

2012-01-01

478

What you should know about simulation and derivatives  

Microsoft Academic Search

Derivatives (or gradients) are important for both sensitivity analysis and optimization, and in simulation models, these can often be estimated efficiently using various methods other than brute-force finite differences. This article briefly summarizes the main approaches and discusses areas in which the approaches can most fruitfully be applied: queueing, inventory, and finance. In finance, the focus is on derivatives of

Michael C. Fu

2008-01-01

479

Expeditious access to (?)-shikimic acid derivatives for Tamiflu synthesis  

Microsoft Academic Search

A three-step, one-pot process has been developed for the synthesis of 5-epi-shikimic acid derivative 5 using inexpensive and abundant d-ribose as the starting material. Based on this pivotal intermediate, the syntheses of two key shikimic acid derivatives 6 and 7 for Tamiflu have been achieved in a concise and practical fashion.

Hiroshi Osato; Ian L. Jones; Huini Goh; Christina L. L. Chai; Anqi Chen

2011-01-01

480

Study of some improved shellac derivatives as microencapsulating materials.  

PubMed

Shellac was chemically modified to alter its permeability and to prevent its 'after hardening'. Various shellac derivatives such as with succinic anhydride, phthalic anhydride, ethylenediamine and myristic acid were prepared. Salicylic acid granules were coated and evaluated for flow properties, moisture absorption and release characteristics before and after ageing. These derivatives imparted better flow properties and showed excellent ageing properties. PMID:1941444

Sheorey, D S; Kshirsagar, M D; Dorle, A K

481

Derivative spectrophotometric analysis of benzophenone (as an impurity) in phenytoin.  

PubMed

Three simple and rapid spectrophotometric methods were developed for detection and trace determination of benzophenone (the main impurity) in phenytoin bulk powder and pharmaceutical formulations. The first method, zero-crossing first derivative spectrophotometry, depends on measuring the first derivative trough values at 257.6 nm for benzophenone. The second method, zero-crossing third derivative spectrophotometry, depends on measuring the third derivative peak values at 263.2 nm. The third method, ratio first derivative spectrophotometry, depends on measuring the peak amplitudes of the first derivative of the ratio spectra (the spectra of benzophenone divided by the spectrum of 5.0 ?g/mL phenytoin solution) at 272 nm. The calibration graphs were linear over the range of 1-10 ?g/mL. The detection limits of the first and the third derivative methods were found to be 0.04 ?g/mL and 0.11 ?g/mL and the quantitation limits were 0.13 ?g/mL and 0.34 ?g/mL, respectively, while for the ratio derivative method, the detection limit was 0.06 ?g/mL and the quantitation limit was 0.18 ?g/mL. The proposed methods were applied successfully to the assay of the studied drug in phenytoin bulk powder and certain pharmaceutical preparations. The results were statistically compared to those obtained using a polarographic method and were found to be in good agreement. PMID:22152156

Walash, Mohamed Ibrahim; Rizk, Mohamed Salem; Sheribah, Zeinab Awad; Salim, Mohamed Mansour

2011-12-12

482

Synthesis and analgetic activity of nicotinic esters of morphine derivatives.  

PubMed

The synthesis of morphine nicotinates is described using nicotinyl chloride in the presence of pyridine. Isomorphine and isocodeine nicotinates were prepared from the corresponding morphine and codeine derivatives with nicotinic acid in the presence of triphenylphosphine and diethyl azodicarboxylate. Unexpectedly the reaction of 14-hydroxy-dihydromorphinone derivatives was anomalous, enolesters were formed. The analgetic activity of selected compounds was determined. PMID:7904819

Hosztafi, S; Köhegyi, I; Simon, C; Fürst, Z

1993-11-01

483

32 CFR 2400.14 - Use of derivative classification.  

Code of Federal Regulations, 2010 CFR

...IMPLEMENT E.O. 12356; OFFICE OF SCIENCE AND] [Subpart C - Derivative...National Defense OFFICE OF SCIENCE AND TECHNOLOGY POLICY REGULATIONS...IMPLEMENT E.O. 12356; OFFICE OF SCIENCE AND Derivative Classification...originating agency or office of origin who has the authority to...

2009-07-01

484

2 Methoxy Antimycin A Derivatives and Methods of Use.  

National Technical Information Service (NTIS)

Disclosed are 2-methoxy antimycin derivatives or analogs that modulate apoptosis by binding to the hydrophobic groove of a Bcl-2 family member protein (e.g., Bcl-2 or BCl-x.sub.L). The 2-methoxy antimycin derivatives or analogs are used in disclosed metho...

D. M. Hockenbery J. A. Simon S. P. Tzung

2005-01-01

485

Derivation of Equations Describing Solute Transport in Ground Water.  

National Technical Information Service (NTIS)

A general equation describing the three-dimensional transport and dispersion of a reacting solute in flowing ground water is derived from the principle of conservation of mass. The derivation presented in this report is more detailed but less rigorous tha...

L. F. KoniKow D. B. Brove

1977-01-01

486

Metallo-?-lactamase inhibitory activity of phthalic acid derivatives  

Microsoft Academic Search

4-Butyl-3-methylphthalic acid was recognized as a metallo-?-lactamase inhibitor. The structure–activity relationship study of substituted phthalic acids afforded 3-phenylphthalic acid derivatives as potent IMP-1 inhibitors. On the other hand, 3-substituted with 4-hydroxyphenyl phthalic acid derivative displayed a potent combination effect with biapenem (BIPM) against Pseudomonas aeruginosa that produce IMP-1.

Yukiko Hiraiwa; Akihiro Morinaka; Takayoshi Fukushima; Toshiaki Kudo

2009-01-01

487

Metallo-beta-lactamase inhibitory activity of phthalic acid derivatives.  

PubMed

4-Butyl-3-methylphthalic acid was recognized as a metallo-beta-lactamase inhibitor. The structure-activity relationship study of substituted phthalic acids afforded 3-phenylphthalic acid derivatives as potent IMP-1 inhibitors. On the other hand, 3-substituted with 4-hydroxyphenyl phthalic acid derivative displayed a potent combination effect with biapenem (BIPM) against Pseudomonas aeruginosa that produce IMP-1. PMID:19632114

Hiraiwa, Yukiko; Morinaka, Akihiro; Fukushima, Takayoshi; Kudo, Toshiaki

2009-07-09

488

15 Software Product Line Engineering with the UML: Deriving Products  

Microsoft Academic Search

Software product line engineering introduces two new dimensions into the traditional engineering of software-based systems: the variability modeling and the product derivation. The variability gathers characteristics that differ from one product to another, while the product derivation is defined as a complete process of building products from the product line. Software Product Line Engineering with the UML has received a

T. Ziadi; J.-M. Jézéquel

489

The Erroneous Derivative Examples of Eleventh Grade Students  

ERIC Educational Resources Information Center

|The derivative is not only an important subject for mathematics but also is an important subject for engineering, physics, economy, chemistry, and statistics. Especially, mathematics depends on strongly preceding learning and the subject of derivative will be used in university education by all students. Therefore, it is one of the most important…

Gur, Hulya; Barak, Basak

2007-01-01

490

Biological activities and corresponding SARs of andrographolide and its derivatives.  

PubMed

In recent years, pharmaceutical chemists have synthesized large numbers of andrographolide derivatives, which bear important biological activities such as anti-inflammatory, antibacterial, antivirus, antitumor, antidiabetic, and antifeedant. Consequently, corresponding SARs were increasingly obvious. This paper aimed to review all the available literature in this field, highlighting the significant achievements on the structural modification and SARs of andrographolide and its derivatives. PMID:23438057

Zhou, Bin; Zhang, Dayong; Wu, Xiaoming

2013-02-01

491

NOVEL SLURRY PHASE DIESEL CATALYSTS FOR COAL-DERIVED SYNGAS  

SciTech Connect

This report describes research conducted to support the DOE program in novel slurry phase catalysts for converting coal-derived synthesis gas to diesel fuels. The primary objective of this research program is to develop attrition resistant catalysts that exhibit high activities for conversion of coal-derived syngas.

Dr. Dragomir B. Bukur; Dr. Ketil Hanssen; Alec Klinghoffer; Dr. Lech Nowicki; Patricia O'Dowd; Dr. Hien Pham; Jian Xu

2001-01-07

492

Objective auditory threshold estimation using sine-wave derived responses  

Microsoft Academic Search

A derived response method of acquiring frequency specific auditory evoked potentials that utilizes a pure tone in combination with a toneburst is applied to the measurement of hearing sensitivity in guinea pigs, chinchillas and pocket gophers. Two experiments which demonstrate that thresholds acquired via tone-derived responses are 10 to 15 dB more sensitive than thresholds to solitary tonebursts are described.

Linda J. Hood; Charles I. Berlin; Rickye S. Heffner; C. Robin Morehouse; Elliott G. Smith; Elizabeth K. Barlow

1991-01-01

493

Non-Calculus Derivation of the Maximum Power Transfer Theorem  

Microsoft Academic Search

In Electrical Engineering Technology textbooks, the maximum power transfer theorem is usually stated and then maybe demonstrated with experimental or simulated evidence. The derivation is not given, because it is thought that calculus is needed. In this paper, we present a derivation of this theorem without using calculus. The method requires the student to know the algebraic rules of inequalities.

Kenneth V. Cartwright

2008-01-01

494

Functional Characterization of Embryonic Stem Cell-Derived Endothelial Cells  

Microsoft Academic Search

Endothelial cells (EC) derived from embryonic stem cells (ESC) require additional functional characterization before they are used as a cell therapy in order to enhance their potential for engraftment and proliferation. We explore several physiologically relevant functions of ESC-derived EC (ESC-EC), such as its capacity to produce nitric oxide (NO), regulate permeability, activate and express surface molecules for the recruitment

Drew E. Glaser; Robert M. Gower; Nicholas E. Lauer; Kayan Tam; Alicia A. Blancas; Albert J. Shih; Scott I. Simon; Kara E. McCloskey

2011-01-01

495

Quantum derivatives and terahertz gain in a superlattice  

SciTech Connect

Simple formulas describing terahertz absorption and gain in a semiconductor superlattice irradiated by a microwave pump field are derived for the case when the signal frequency is a half harmonic of the pump. A simple qualitative analysis provides a geometric interpretation of the derived formulas, which can be used to determine if gain is feasible.

Shorokhov, A. V. [Ogarev Mordovian State University (Russian Federation)], E-mail: shorokhovav@math.mrsu.ru; Alekseev, K. N. [University of Oulu (Finland)

2007-07-15

496

ASSESSMENT OF THE NEUROTOXICITY OF PARENTERAL ARTEMISININ DERIVATIVES IN MICE  

Microsoft Academic Search

In all experimental mammals tested (rats, dogs, primates), intramuscular injections of the oil-soluble antimalarial artemisinin derivatives artemether and arteether have produced an unusual pattern of selective damage to brain stem centers predominantly involved in auditory processing and vestibular reflexes. Artesunate, the most widely used of these compounds, is a water soluble hemisuccinate derivative given parenterally either by intravenous or intramuscular

APICHART NONTPRASERT; MARIKA NOSTEN-BERTRAND; SASITHON PUKRITTAYAKAMEE; SIRIVAN VANIJANONTA; BRIAN J. ANGUS; NICHOLAS J. WHITE

497

STUDIES OF THE NEUROTOXICITY OF ORAL ARTEMISININ DERIVATIVES IN MICE  

Microsoft Academic Search

Intramuscular injections of high doses of the oil-soluble antimalarial artemisinin derivatives artemether and arteether produce an unusual pattern of selective damage to brain stem centers in experimental mammals, pre- dominantly those involved in auditory processing and vestibular reflexes. We have shown recently in adult Swiss albino mice that parenteral artesunate, a water-soluble