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1

Cytochrome P450-mediated activation of the fragrance compound geraniol forms potent contact allergens  

SciTech Connect

Contact sensitization is caused by low molecular weight compounds which penetrate the skin and bind to protein. In many cases, these compounds are activated to reactive species, either by autoxidation on exposure to air or by metabolic activation in the skin. Geraniol, a widely used fragrance chemical, is considered to be a weak allergen, although its chemical structure does not indicate it to be a contact sensitizer. We have shown that geraniol autoxidizes and forms allergenic oxidation products. In the literature, it is suggested but not shown that geraniol could be metabolically activated to geranial. Previously, a skin-like CYP cocktail consisting of cutaneous CYP isoenzymes, was developed as a model system to study cutaneous metabolism. In the present study, we used this system to investigate CYP-mediated activation of geraniol. In incubations with the skin-like CYP cocktail, geranial, neral, 2,3-epoxygeraniol, 6,7-epoxygeraniol and 6,7-epoxygeranial were identified. Geranial was the main metabolite formed followed by 6,7-epoxygeraniol. The allergenic activities of the identified metabolites were determined in the murine local lymph node assay (LLNA). Geranial, neral and 6,7-epoxygeraniol were shown to be moderate sensitizers, and 6,7-epoxygeranial a strong sensitizer. Of the isoenzymes studied, CYP2B6, CYP1A1 and CYP3A5 showed high activities. It is likely that CYP1A1 and CYP3A5 are mainly responsible for the metabolic activation of geraniol in the skin, as they are expressed constitutively at significantly higher levels than CYP2B6. Thus, geraniol is activated through both autoxidation and metabolism. The allergens geranial and neral are formed via both oxidation mechanisms, thereby playing a large role in the sensitization to geraniol.

Hagvall, Lina [Department of Chemistry, Dermatochemistry and Skin Allergy, University of Gothenburg, SE-412 96 Gothenburg (Sweden); Baron, Jens Malte [Department of Dermatology and Allergology, University Hospital RWTH Aachen, Aachen (Germany); Boerje, Anna [Department of Chemistry, Dermatochemistry and Skin Allergy, University of Gothenburg, SE-412 96 Gothenburg (Sweden); Weidolf, Lars [Discovery DMPK and Bioanalytical Chemistry, AstraZeneca R and D Moelndal, SE-421 83 Moelndal (Sweden); Merk, Hans [Department of Dermatology and Allergology, University Hospital RWTH Aachen, Aachen (Germany); Karlberg, Ann-Therese [Department of Chemistry, Dermatochemistry and Skin Allergy, University of Gothenburg, SE-412 96 Gothenburg (Sweden)], E-mail: karlberg@chem.gu.se

2008-12-01

2

Hydroperoxides in oxidized d -limonene identified as potent contact allergens  

Microsoft Academic Search

Hydroperoxides of d-limonene were shown to be potent contact allergens when studied in guinea-pigs. Limonene-2-hydroperoxide (2-hydroperoxy-p-mentha-6,8-diene, a mixture of trans and cis isomers) was synthesized for the first time. The ratio between the trans and cis forms was 3:1. These two hydroperoxides were identified as the major hydroperoxides in autoxidized d-limonene. In photooxidized d-limonene, they constituted a minor part of

A.-T. Karlberg; L. P. Shao; U. Nilsson; E. GÄfvert; J. L. G. Nilsson

1994-01-01

3

Method for forming metal contacts  

DOEpatents

Methods of forming metal contacts with metal inks in the manufacture of photovoltaic devices are disclosed. The metal inks are selectively deposited on semiconductor coatings by inkjet and aerosol apparatus. The composite is heated to selective temperatures where the metal inks burn through the coating to form an electrical contact with the semiconductor. Metal layers are then deposited on the electrical contacts by light induced or light assisted plating.

Reddington, Erik; Sutter, Thomas C; Bu, Lujia; Cannon, Alexandra; Habas, Susan E; Curtis, Calvin J; Miedaner, Alexander; Ginley, David S; Van Hest, Marinus Franciscus Antonius Maria

2013-09-17

4

Pion form factor from a contact interaction  

SciTech Connect

In a Poincare-covariant vector-boson-exchange theory, the pion possesses components of pseudovector origin, which materially influence its observable properties. For a range of such quantities, we explore the consequences of a momentum-independent interaction, regularized in a symmetry-preserving manner. The contact interaction, while capable of describing pion static properties, produces a form factor whose evolution for Q{sup 2}>0.17 GeV{sup 2} disagrees markedly with experiment and whose asymptotic power-law behavior conflicts strongly with perturbative QCD.

Gutierrez-Guerrero, L. X.; Bashir, A. [Instituto de Fisica y Matematicas, Universidad Michoacana de San Nicolas de Hidalgo, Apartado Postal 2-82, Morelia, Michoacan 58040 (Mexico); Cloeet, I. C. [Department of Physics, University of Washington, Seattle, Washington 98195 (United States); Roberts, C. D. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, Peking University, Beijing 100871 (China)

2010-06-15

5

Techniques for forming contacts to quantum well transistors  

US Patent & Trademark Office Database

Techniques are disclosed for providing a low resistance self-aligned contacts to devices formed in a semiconductor heterostructure. The techniques can be used, for example, for forming contacts to the gate, source and drain regions of a quantum well transistor fabricated in III-V and SiGe/Ge material systems. Unlike conventional contact process flows which result in a relatively large space between the source/drain contacts to gate, the resulting source and drain contacts provided by the techniques described herein are self-aligned, in that each contact is aligned to the gate electrode and isolated therefrom via spacer material.

Pillarisetty; Ravi (Portland, OR); Chu-Kung; Benjamin (Hillsboro, OR); Hudait; Mantu K. (Portland, OR); Radosavljevic; Marko (Beaverton, OR); Kavalieros; Jack T. (Portland, OR); Rachmady; Willy (Beaverton, OR); Mukherjee; Niloy (Beaverton, OR); Chau; Robert S. (Beaverton, OR)

2013-02-05

6

An Electron Fractographic Study of Spalls Formed During Rolling Contact.  

National Technical Information Service (NTIS)

A technique is described for making fractographs of fatigue spalls formed in bearings during rolling contact. Results are given which illustrate the usefulness of the method in identifying the fracture modes encountered in spalls. All of the fractures obs...

S. F. Borgese W. J. Pantalone

1967-01-01

7

Method of forming contacts for a back-contact solar cell  

DOEpatents

Methods of forming contacts for back-contact solar cells are described. In one embodiment, a method includes forming a thin dielectric layer on a substrate, forming a polysilicon layer on the thin dielectric layer, forming and patterning a solid-state p-type dopant source on the polysilicon layer, forming an n-type dopant source layer over exposed regions of the polysilicon layer and over a plurality of regions of the solid-state p-type dopant source, and heating the substrate to provide a plurality of n-type doped polysilicon regions among a plurality of p-type doped polysilicon regions.

Manning, Jane

2013-07-23

8

Identification and Quantification of Potent Odorants Formed by Toasting of Wheat Bread  

Microsoft Academic Search

Slices of wheat bread were toasted until a distinct intensity of brown colour was attained. Potent odorants formed were evaluated by aroma extract dilution analysis and gas chromatography\\/olfactometry of headspace samples. Compounds showing high dilution factors were quantified, and their aroma activity values (OAV, ratio of concentration to odour threshold) were calculated on the basis of their odour thresholds in

Michael Rychlik; Werner Grosch

1996-01-01

9

78 FR 23898 - Notice of Request for a New Information Collection (Accredited Laboratory Contact Update Form)  

Federal Register 2010, 2011, 2012, 2013

...Information Collection (Accredited Laboratory Contact Update Form) AGENCY: Food Safety and...collection regarding the compilation of updated contact information for Accredited Laboratories...through Friday. FOR FURTHER INFORMATION CONTACT: Contact John O'Connell,...

2013-04-23

10

75 FR 61245 - Proposed Collection; Comment Request for the EFTPS Primary Contact Information Change Form  

Federal Register 2010, 2011, 2012, 2013

...Comment Request for the EFTPS Primary Contact Information Change Form AGENCY: Internal...comments concerning the EFTPS Primary Contact Information Change Form. DATES: Written...Washington, DC 20224. FOR FURTHER INFORMATION CONTACT: Requests for additional...

2010-10-04

11

78 FR 58608 - Proposed Collection; Comment Request for the EFTPS Primary Contact Information Change Form  

Federal Register 2010, 2011, 2012, 2013

...Comment Request for the EFTPS Primary Contact Information Change Form AGENCY: Internal...comments concerning the EFTPS Primary Contact Information Change Form. DATES: Written...Washington, DC 20224. FOR FURTHER INFORMATION CONTACT: Requests for additional...

2013-09-24

12

Organic light-emitting diodes formed by soft contact lamination  

PubMed Central

Although tremendous progress has been made in organic light-emitting diodes (OLEDs), with few exceptions they are fabricated in the standard way by sequentially depositing active layers and electrodes onto a substrate. Here we describe a different approach for building OLEDs, which is based on physical lamination of thin metal electrodes supported by an elastomeric layer against an electroluminescent organic. This method relies only on van der Waals interactions to establish spatially homogeneous, intimate contacts between the electrodes and the organic. We find that devices fabricated in this manner have better performance than those constructed with standard processing techniques. The lamination approach avoids forms of disruption that can be introduced at the electrode/organic interface by metal evaporation and has a reduced sensitivity to pinhole or partial pinhole defects. In addition, because this form of “soft” contact lamination is intrinsically compatible with the techniques of soft lithography, it is easy to build patterned OLEDs with feature sizes into the nanometer regime. This method provides a new route to OLEDs for applications ranging from high performance displays to storage and lithography systems that rely on subwavelength light sources.

Lee, Tae-Woo; Zaumseil, Jana; Bao, Zhenan; Hsu, Julia W. P.; Rogers, John A.

2004-01-01

13

Feeding deterrence and contact toxicity of Stemona alkaloids-a source of potent natural insecticides.  

PubMed

On the basis of chronic feeding bioassays with neonate larvae of Spodoptera littoralis reared on an artificial diet, the methanolic leaf and root extracts from Stemona collinsae displayed very high insect toxicity compared to those of two Aglaia species, a commercial Pyrethrum extract, and azadirachtin, whereas S. tuberosa extracts demonstrated low activity in roots and no activity in leaves. Beyond that, in leaf disk choice tests against fifth instar larvae, S. collinsae showed strong antifeedant activity, whereas S. tuberosa was characterized by remarkable repellency. The anti-insect properties of both species were based on pyrrolo[1,2-a]azepine alkaloids, from which didehydrostemofoline (asparagamine A) was the major compound of the roots of S. collinsae, exhibiting the highest toxicity in feeding assays. Saturation and hydroxylation of the side chain in the co-occurring stemofoline and 2'-hydroxystemofoline, respectively, led to an increasing loss of activity. Contact toxicity tests with stemofoline and didehydrostemofoline exhibited even higher activities than those of Pyrethrum extract. Tuberostemonine was the dominating alkaloid in the roots of S. tuberosa, showing outstanding repellency but no toxic effects. PMID:12381121

Brem, Brigitte; Seger, Christoph; Pacher, Thomas; Hofer, Otmar; Vajrodaya, Srunya; Greger, Harald

2002-10-23

14

Flavonoids, potent inhibitors of the human P-form phenolsulfotransferase. Potential role in drug metabolism and chemoprevention.  

PubMed

The common dietary constituent quercetin was a potent inhibitor of sulfoconjugation of acetaminophen and minoxidil by human liver cytosol, partially purified P-form phenolsulfotransferase (PST), and recombinant P-form PST, with IC50 values of 0.025-0.095 microM. Quercetin inhibition of acetaminophen was noncompetitive with respect to acceptor substrate, with a Ki value of 0.067 microM. A number of other flavonoids, such as fisetin, galangin, myricetin, kaempferol, chrysin, and apigenin, were also potent inhibitors of P-form PST-mediated sulfation, with IC50 values < 1 microM. Studies of structural analogs indicated the flavonoid 7-hydroxyl group as particularly important for potent inhibition. Potential human metabolites of quercetin were poor inhibitors. Curcumin, genistein, and ellagic acid (other polyphenolic natural products) were also inhibitors of P-form PST, with IC50 values of 0.38-34.8 microM. Quercetin was also shown to inhibit sulfoconjugation by the human hepatoma cell line Hep G2. Although less potent in this intact cell system (IC50 2-5 microM), quercetin was still more potent than 2,6-dichloro-4-nitrophenol, the classical P-form PST inhibitor that has been shown to be an inhibitor also in vivo. These observations suggest the potential for clinically important drug interactions, as well as a possible role for flavonoids as chemopreventive agents in sulfation-induced carcinogenesis. PMID:8742236

Eaton, E A; Walle, U K; Lewis, A J; Hudson, T; Wilson, A A; Walle, T

1996-02-01

15

A finite element analysis of elasto-plastic contact problems in metal forming  

Microsoft Academic Search

A contact finite element has been developed to solve elasto-plastic contact problems frequently encountered in metal forming processes. The element developed is based on the methodology originally used for solving elastic contact problems. It employs an interface spring algorithm that yields a symmetric type of elemental stiffness matrix and that can be conveniently handled by most exiting finite element solvers.

F. H. Lin; A. A. Tseng

1998-01-01

16

Traditional and New Forms of Contact Between Grandparents and Grandchildren  

Microsoft Academic Search

The article concerns factors predicting different types of both traditional and modern forms of grandparent–grandchild communication in a sample of Finnish grandparents and in a separate sample of Finnish grandchildren between 11–13 and 16–17 years of age. The data has been gathered using a New Technologies Questionnaire in both samples and the Grandparent Role Inventory in the grandparent sample. In

Helena Hurme; Susanne Westerback; Tatiana Quadrello

2010-01-01

17

Al-Si contacts formed by ion irradiation and post-annealing  

Microsoft Academic Search

Al-Si contacts have been formed by implantation of As ions through Al-Si interfaces followed by heat treatment at 400–500 °C for 10 min. The erosion of Si proceeds uniformly in contact areas at the sintering temperatures. Diodes using Al-Si contacts produced by this technique have been fabricated on thin n+ layers in p-type Si substrates with junction depths of 0.35

L. S. Hung; J. W. Mayer; M. Zhang; E. D. Wolf

1983-01-01

18

The potent vasodilator ethyl nitrite is formed upon reaction of nitrite and ethanol under gastric conditions  

Microsoft Academic Search

By acting as a bioreactor, affording chemical and mechanical conditions for the reaction between dietary components, the stomach may be a source of new bioactive molecules. Using gas chromatography-mass spectrometry we here demonstrate that, under acidic gastric conditions, ethyl nitrite is formed in µM concentrations from the reaction of red wine or distilled alcoholic drinks with physiological amounts of nitrite.

Bruno Gago; Thomas Nyström; Carlos Cavaleiro; Bárbara S. Rocha; Rui M. Barbosa; João Laranjinha; Jon O. Lundberg

2008-01-01

19

A New Form of Rolling Contact Damage in Grease-Lubricated, Deep-Groove Ball Bearings  

Microsoft Academic Search

A new form of rolling contact damage was discovered in the fatigue tests of series 6206 deep groove ball bearings under pure radial load with grease lubrication. The appearance of the damage reveals a few cracks at right angles to the rolling direction of the ball, along with the formation of a dent about 20 ? m deep in the

Takeo Yoshioka; Shigeo Simizu; Hirokazu Shimoda

2009-01-01

20

Pixantrone can be activated by formaldehyde to generate a potent DNA adduct forming agent  

PubMed Central

Mitoxantrone is an anti-cancer agent used in the treatment of breast and prostate cancers. It is classified as a topoisomerase II poison, however can also be activated by formaldehyde to generate drug–DNA adducts. Despite identification of this novel form of mitoxantrone–DNA interaction, excessively high, biologically irrelevant drug concentrations are necessary to generate adducts. A search for mitoxantrone analogues that could potentially undergo this reaction with DNA more efficiently identified Pixantrone as an ideal candidate. An in vitro crosslinking assay demonstrated that Pixantrone is efficiently activated by formaldehyde to generate covalent drug–DNA adducts capable of stabilizing double-stranded DNA in denaturing conditions. Pixantrone–DNA adduct formation is both concentration and time dependent and the reaction exhibits an absolute requirement for formaldehyde. In a direct comparison with mitoxantrone–DNA adduct formation, Pixantrone exhibited a 10- to 100-fold greater propensity to generate adducts at equimolar formaldehyde and drug concentrations. Pixantrone–DNA adducts are thermally and temporally labile, yet they exhibit a greater thermal midpoint temperature and an extended half-life at 37°C when compared to mitoxantrone–DNA adducts. Unlike mitoxantrone, this enhanced stability, coupled with a greater propensity to form covalent drug–DNA adducts, may endow formaldehyde-activated Pixantrone with the attributes required for Pixantrone–DNA adducts to be biologically active.

Evison, Ben J.; Mansour, Oula C.; Menta, Ernesto; Phillips, Don R.; Cutts, Suzanne M.

2007-01-01

21

Optimization of contact forces in tailor-welded blanks forming process  

Microsoft Academic Search

To attain the objective of minimizing the harmful movement of the weld joint in tailor-welded blanks (TWBs) forming, a novel\\u000a optimization methodology based on dynamic explicit finite element simulation is presented to determine optimum contact forces.\\u000a In this methodology, forming limit diagram (FLD) models developed for different types of TWBs are treated as a criterion of\\u000a constraint in optimizations. Due

Jun Zhang

2007-01-01

22

Effects of varying machine stiffness and contact area in UltraForm Finishing  

NASA Astrophysics Data System (ADS)

UltraForm Finishing (UFF) is a deterministic, subaperture, computer numerically controlled, grinding and polishing platform designed by OptiPro Systems. UFF is used to grind and polish a variety optics from simple spherical to fully freeform, and numerous materials from glasses to optical ceramics. The UFF system consists of an abrasive belt around a compliant wheel that rotates and contacts the part to remove material. This work aims to measure the stiffness variations in the system and how it can affect material removal rates. The stiffness of the entire system is evaluated using a triaxial load cell to measure forces and a capacitance sensor to measure deviations in height. Because the wheel is conformal and elastic, the shapes of contact areas are also of interest. For the scope of this work, the shape of the contact area is estimated via removal spot. The measured forces and removal spot area are directly related to material removal rate through Preston's equation. Using our current testing apparatus, we will demonstrate stiffness measurements and contact areas for a single UFF belt during different states of its lifecycle and assess the material removal function from spot diagrams as a function of wear. This investigation will ultimately allow us to make better estimates of Preston's coefficient and develop spot-morphing models in an effort to more accurately predict instantaneous material removal functions throughout the lifetime of a belt.

Briggs, Dennis E.; Echaves, Samantha; Pidgeon, Brendan; Travis, Nathan; Ellis, Jonathan D.

2013-09-01

23

Thin Film Solid-State Reactions Forming Carbides as Contact Materials for Carbon-Containing Semiconductors  

SciTech Connect

Metal carbides are good candidates to contact carbon-based semiconductors (SiC, diamond, and carbon nanotubes). Here, we report on an in situ study of carbide formation during the solid-state reaction between thin films. The solid-state reaction was examined between 11 transition metals (W, Mo, Fe, Cr, V, Nb, Mn, Ti, Ta, Zr, and Hf) and an amorphous carbon layer. Capping layers (C or TiN) of different thicknesses were applied to prevent oxidation. Carbide formation is evidenced for nine metals and the phases formed have been identified (for a temperature ranging from 100 to 1100 C). W first forms W{sub 2}C and then WC; Mo forms Mo{sub 2}C; Fe forms Fe{sub 3}C; Cr first forms metastable phases Cr{sub 2}C and Cr{sub 3}C{sub 2-x}, and finally forms Cr{sub 3}C{sub 2}; V forms VC{sub x}; Nb transforms into Nb{sub 2}C followed by NbC; Ti forms TiC; Ta first forms Ta{sub 2}C and then TaC; and Hf transforms into HfC. The activation energy for the formation of the various carbide phases has been obtained by in situ x-ray diffraction.

Leroy,W.; Detavernier, C.; Van Meirhaeghe, R.; Lavoie, C.

2007-01-01

24

Thin film solid-state reactions forming carbides as contact materials for carbon-containing semiconductors  

NASA Astrophysics Data System (ADS)

Metal carbides are good candidates to contact carbon-based semiconductors (SiC, diamond, and carbon nanotubes). Here, we report on an in situ study of carbide formation during the solid-state reaction between thin films. The solid-state reaction was examined between 11 transition metals (W, Mo, Fe, Cr, V, Nb, Mn, Ti, Ta, Zr, and Hf) and an amorphous carbon layer. Capping layers (C or TiN) of different thicknesses were applied to prevent oxidation. Carbide formation is evidenced for nine metals and the phases formed have been identified (for a temperature ranging from 100 to 1100 °C). W first forms W2C and then WC; Mo forms Mo2C; Fe forms Fe3C; Cr first forms metastable phases Cr2C and Cr3C2-x, and finally forms Cr3C2; V forms VCx; Nb transforms into Nb2C followed by NbC; Ti forms TiC; Ta first forms Ta2C and then TaC; and Hf transforms into HfC. The activation energy for the formation of the various carbide phases has been obtained by in situ x-ray diffraction.

Leroy, W. P.; Detavernier, C.; van Meirhaeghe, R. L.; Lavoie, C.

2007-03-01

25

The emergence of potent forms of methamphetamine in Sydney, Australia: a case study of the IDRS as a strategic early warning system.  

PubMed

A striking finding of the Illicit Drug Reporting System (IDRS) in recent years has concerned the emergence in Sydney of a number of different forms of potent methamphetamine. This paper demonstrates the operation of the IDRS in detecting and documenting an increase in both the availability and use of these forms of methamphetamine in Sydney, and Australia more widely, since 1998. Data from different components of the IDRS are utilized to propose that there are currently at least three forms of methamphetamine available in Sydney that are considered by the market to be distinct commodities: methamphetamine powder ('speed'), base methamphetamine ('base') and crystalline methamphetamine ('ice'/'shabu'/'crystal meth'). Base and ice are more potent forms of methamphetamine than speed, and international experience, along with preliminary data obtained from the IDRS, suggest that their use is associated with harms in a number of domains. PMID:12537703

Topp, Libby; Degenhardt, Louisa; Kaye, Sharlene; Darke, Shane

2002-12-01

26

Specific Contact Resistance Measurement of Screen-Printed Ag Metal Contacts Formed on Heavily Doped Emitter Region in Multicrystalline Silicon Solar Cells  

NASA Astrophysics Data System (ADS)

Multicrystalline silicon (mc-Si) wafers are widely used to develop low-cost high-efficiency screen-printed solar cells. In this study, the electrical properties of screen-printed Ag metal contacts formed on heavily doped emitter region in mc-Si solar cells have been investigated. Sintering of the screen-printed metal contacts was performed by a co-firing step at 725°C in air ambient followed by low-temperature annealing at 450°C for 15 min. Measurement of the specific contact resistance ( ? c) of the Ag contacts was performed by the three-point probe method, showing a best value of ? c = 1.02 × 10-4 ? cm2 obtained for the Ag contacts. This value is considered as a good figure of merit for screen-printed Ag electrodes formed on a doped mc-Si surface. The plot of ? c versus the inverse of the square root of the surface doping level ( N {s/-½}) follows a linear relationship for impurity doping levels N s ? 1019 atoms/cm3. The power losses due to current traveling through various resistive components of finished solar cells were calculated by using standard expressions. Cross-sectional scanning electron microscopy (SEM) views of the Ag metal and doped mc-Si region show that the Ag metal is firmly coalesced with the doped mc-Si surface upon sintering at an optimum firing temperature of 725°C.

Vinod, P. Narayanan

2013-10-01

27

Ion Channel-Forming Alamethicin Is a Potent Elicitor of Volatile Biosynthesis and Tendril Coiling. Cross Talk between Jasmonate and Salicylate Signaling in Lima Bean  

Microsoft Academic Search

Alamethicin (ALA), a voltage-gated, ion channel-forming peptide mixture from Trichoderma viride, is a potent elicitor of the biosynthesis of volatile compounds in lima bean (Phaseolus lunatus). Unlike elicitation with jasmonic acid or herbivore damage, the blend of substances emitted comprises only the two homoterpenes, 4,11-dimethylnona-1,3,7-triene and 4,8,12-trimethyltrideca-1,3,7,11-tetraene, and methyl salicylate. Inhibition of octadecanoid signaling by aristolochic acid and phenidone as

Jurgen Engelberth; Thomas Koch; Gode Schuler; Nadine Bachmann; Jana Rechtenbach; Wilhelm Boland

2001-01-01

28

Induction of Ca 21 Calmodulin Signaling by Hard-Surface Contact Primes Colletotrichum gloeosporioides Conidia To Germinate and Form Appressoria  

Microsoft Academic Search

Hard-surface contact primes the conidia of Colletotrichum gloeosporioides to respond to plant surface waxes and a fruit-ripening hormone, ethylene, to germinate and form the appressoria required for infection of the host. Our efforts to elucidate the molecular events in the early phase of the hard-surface contact found that EGTA (5 mM) and U73122 (16 nM), an inhibitor of phospholipase C,

YEON-KI KIM; DAOXIN LI; PAPPACHAN E. KOLATTUKUDY

1998-01-01

29

Method of forming platinum and platinum silicide Schottky contacts on beta-silicon carbide  

NASA Astrophysics Data System (ADS)

Platinum Schottky contacts remaining stable up to 800 C have been produced. The adhesion of the platinum deposited at slightly elevated temperatures is good. Platinum provides a metallization that is physically rugged and thermally stable. The Schottky contacts are made on B-Silicon carbide.

Papanicolaou, Nicolas A.

1993-12-01

30

Laser method for forming low-resistance ohmic contacts on semiconducting oxides  

DOEpatents

This invention is a new method for the formation of high-quality ohmic contacts on wide-band-gap semiconducting oxides. As exemplified by the formation of an ohmic contact on n-type BaTiO.sub.3 containing a p-n junction, the invention entails depositing a film of a metallic electroding material on the BaTiO.sub.3 surface and irradiating the film with a Q-switched laser pulse effecting complete melting of the film and localized melting of the surface layer of oxide immediately underlying the film. The resulting solidified metallic contact is ohmic, has unusually low contact resistance, and is thermally stable, even at elevated temperatures. The contact does not require cleaning before attachment of any suitable electrical lead. This method is safe, rapid, reproducible, and relatively inexpensive.

Narayan, Jagdish (Knoxville, TN)

1981-01-01

31

The long-term effects of contact and noncontact forms of child sexual abuse in a sample of university men  

Microsoft Academic Search

The long-term effects of child sexual abuse were examined in a sample of 284 university men. After controlling for the effects of dysfunctional parenting behaviors, a history of abuse involving physical contact was found to be associated with elevated scores on all subscales of the Brief Symptom Inventory. The comparison involving noncontact forms of abuse produced no significant abuse related

Steven J. Collings

1995-01-01

32

The microstructure and electrical properties of contacts formed in the Ni/Al/Si system due to rapid thermal processing  

NASA Astrophysics Data System (ADS)

The microstructure and electrical properties of the contacts formed in the Ni(30 nm)/Al(10 nm)/100-line n-Si system due to rapid thermal processing were studied at temperatures between 300 and 900 C. A melting at the intermediate Al layer was observed already at about 580 C after 2-s heat treatments. This rapid eutectic melting, assumed to initiate at the Al-Si interface, resulted in the formation of a unique contact composed of the Ni(Al/0.5/Si/0.5/)/Al3Ni/Ni(x)Si(y)/n-Si structure with fairly smooth interfaces between the layers. The sheet resistance of the layers and the Schottky barrier height of the contact were measured as a function of the rapid thermal processing temperatures. As a result of the eutectic melting reaction at 580 C, the sheet resistance of the formed layers decreased from 3.2 to 2.6 ohm/unit area, the Schottky barrier height between the layers and Si increased from 0.61-0.76 eV, and the effective electrically active area of the contact increased. These electrical properties are discussed in correlation with the microstructure formed in the Ni/Al/Si system due to the rapid thermal processing.

Katz, A.; Komem, Y.

1988-06-01

33

Thin film solid-state reactions forming carbides as contact materials for carbon-containing semiconductors  

Microsoft Academic Search

Metal carbides are good candidates to contact carbon-based semiconductors (SiC, diamond, and carbon nanotubes). Here, we report on an in situ study of carbide formation during the solid-state reaction between thin films. The solid-state reaction was examined between 11 transition metals (W, Mo, Fe, Cr, V, Nb, Mn, Ti, Ta, Zr, and Hf) and an amorphous carbon layer. Capping layers

W. P. Leroy; C. Detavernier; R. L. van Meirhaeghe; C. Lavoie

2007-01-01

34

A linearly conforming radial point interpolation method (LC-RPIM) for contact problems in metal forming analysis  

Microsoft Academic Search

The total Lagrangian formulation and implementation of a linearly conforming radial point interpolation method (LC-RPIM) is\\u000a presented for the analysis of contact-impact problems with large deformations and for the simulation of metal forming processes.\\u000a In present method, the displacement field function is approximated using RPIM shape functions possessing Kronecker delta function\\u000a property, which facilitates easy the enforcement of essential boundary

Zheng Gang; Cui Xiangyang; Li Guangyao; Wu Suzhen

2010-01-01

35

The microstructure and electrical properties of contacts formed in the Ti\\/Al\\/Si system due to rapid thermal processing  

Microsoft Academic Search

The microstructure and electrical properties of the contacts formed in the Ti(30 nm)\\/Al(10 nm)\\/?100?p-type Si system due to rapid thermal processing at temperatures between 300 and 800 °C were studied extensively. An eutectic melting, initiated at the Al\\/Si interface, was already observed after 2 s at 580 °C. This rapid melting, which was first observed by the authors in the

Y. Komem; A. Katz

1990-01-01

36

Structure of Apo- and Monometalated Forms of NDM-1--A Highly Potent Carbapenem-Hydrolyzing Metallo-?-Lactamase  

PubMed Central

The New Delhi Metallo-?-lactamase (NDM-1) gene makes multiple pathogenic microorganisms resistant to all known ?-lactam antibiotics. The rapid emergence of NDM-1 has been linked to mobile plasmids that move between different strains resulting in world-wide dissemination. Biochemical studies revealed that NDM-1 is capable of efficiently hydrolyzing a wide range of ?-lactams, including many carbapenems considered as “last resort” antibiotics. The crystal structures of metal-free apo- and monozinc forms of NDM-1 presented here revealed an enlarged and flexible active site of class B1 metallo-?-lactamase. This site is capable of accommodating many ?-lactam substrates by having many of the catalytic residues on flexible loops, which explains the observed extended spectrum activity of this zinc dependent ?-lactamase. Indeed, five loops contribute “keg” residues in the active site including side chains involved in metal binding. Loop 1 in particular, shows conformational flexibility, apparently related to the acceptance and positioning of substrates for cleavage by a zinc-activated water molecule.

Kim, Youngchang; Sacchettini, James; Joachimiak, Andrzej

2011-01-01

37

Atmospherically stable nanoscale zero-valent iron particles formed under controlled air contact: characteristics and reactivity.  

PubMed

Atmospherically stable NZVI (nanoscale zero-valent iron) particles were produced by modifying shell layers of Fe(H2) NZVI particles (RNIP-10DS) by using a controlled air contact method. Shell-modified NZVI particles were resistant to rapid aerial oxidation and were shown to have TCE degradation rate constants that were equivalent to 78% of those of pristine NZVI particles. Fe(H2) NZVI particles that were vigorously contacted with air (rapidly oxidized) showed a substantially compromised reactivity. Aging of shell-modified particles in water for one day resulted in a rate increase of 54%, implying that depassivation of the shell would play an important role in enhancing reactivity. Aging of shell-modified particles in air led to rate decreases by 14% and 46% in cases of one week and two months of aging, respectively. A series of instrumental analyses using transmission electron microscopy, X-ray diffractography, X-ray photoelectron spectroscopy, and X-ray absorption near-edge structure showed that the shells of modified NZVI particles primarily consisted of magnetite (Fe(3)O(4)). Analyses also implied that the new magnetite layer produced during shell modification was protective against shell passivation. Aging of shell-modified particles in water yielded another major mineral phase, goethite (alpha-FeOOH), whereas aging in air produced additional shell phases such as wustite (FeO), hematite (alpha-Fe(2)O(3)), and maghemite (gamma-Fe(2)O(3)). PMID:20136088

Kim, Hong-Seok; Ahn, Jun-Young; Hwang, Kyung-Yup; Kim, Il-Kyu; Hwang, Inseong

2010-03-01

38

Physical controls and resulting morphological forms of Quaternary ice-contact volcanoes in western Canada  

Microsoft Academic Search

Volcanism in association with large quantities of ice manifests itself in a variety of morphological forms developed under differing physical conditions. These physical conditions include the location, amount, thickness, and type of confining ice, the location and quantity of trapped water, and the surrounding topography. Ice in the form of thick continental ice sheets, thinner alpine glaciers or even perennial

Catherine J Hickson

2000-01-01

39

Complex formation in aqueous solution and in the solid state of the potent insulin-enhancing V(IV)O2+ compounds formed by picolinate and quinolinate derivatives.  

PubMed

The complexation of V(IV)O(2+) ion with 10 picolinate and quinolinate derivatives, provided with the donor set (N, COO(-)), was studied in aqueous solution and in the solid state through the combined application of potentiometric (pH-titrations), spectroscopic (EPR, UV/vis and IR spectroscopy), and computational (density functional theory (DFT) calculations) methods. Such derivatives, that form potent insulin-enhancing V(IV)O(2+) compounds, are picolinic (picH), 6-methylpicolinic (6-mepicH), 3-methylpicolinic (3-mepicH), 5-butylpicolinic or fusaric (fusarH), 6-methyl-2,3-pyridindicarboxylic (6-me-2,3-pdcH(2)), 2-pyridylacetic (2-pyacH), 2-quinolinecarboxylic or quinaldic (quinH), 4-hydroxyquinoline-2-carboxylic or kynurenic (kynurH), 1-isoquinolinecarboxylic (1-iqcH) and 3-isoquinolinecarboxylic (3-iqcH) acid. On the basis of the potentiometric, spectroscopic, and DFT results, they were divided into the classes A, B, and C. The ligands belonging to class A (3-mepicH, 1-iqcH, 2-pyacH) form square pyramidal complexes in aqueous solution and in the solid state, and those belonging to class B (picH, fusarH, 3-iqcH) form cis-octahedral species, in which the two ligands adopt an (equatorial-equatorial) and an (equatorial-axial) arrangement and one water molecule occupies an equatorial site in cis position with respect to the V?O bond. Class C ligands (6-mepicH, 6-me-2,3-pdcH(2), quinH, kynurH) yield bis chelated species, that in water are in equilibrium between the square pyramidal and trans-octahedral form, where both the ligand molecules adopt an (equatorial-equatorial) arrangement and one water is in trans position with respect to the V?O group. The trans-octahedral compounds are characterized by an anomalous electron paramagnetic resonance (EPR) response, with A(z) value being reduced by about 10% with respect to the prediction of the "additivity rule". DFT methods allow to calculate the structure, (51)V hyperfine coupling constant (A(z)), the stretching frequency of V?O bond (?(V?O)), the relative stability in aqueous solution, and the electronic structure and molecular orbital composition of bis chelated complexes. The results were used to explain the biotransformation of these potent insulin-enhancing compounds in blood serum. PMID:21226475

Lodyga-Chruscinska, Elzbieta; Micera, Giovanni; Garribba, Eugenio

2011-01-12

40

Induction of Ca2+-Calmodulin Signaling by Hard-Surface Contact Primes Colletotrichum gloeosporioides Conidia To Germinate and Form Appressoria  

PubMed Central

Hard-surface contact primes the conidia of Colletotrichum gloeosporioides to respond to plant surface waxes and a fruit-ripening hormone, ethylene, to germinate and form the appressoria required for infection of the host. Our efforts to elucidate the molecular events in the early phase of the hard-surface contact found that EGTA (5 mM) and U73122 (16 nM), an inhibitor of phospholipase C, inhibited (50%) germination and appressorium formation. Measurements of calmodulin (CaM) transcripts with a CaM cDNA we cloned from C. gloeosporioides showed that CaM was induced by hard-surface contact maximally at 2 h and then declined; ethephon enhanced this induction. The CaM antagonist, compound 48/80, completely inhibited conidial germination and appressorium formation at a concentration of 3 ?M, implying that CaM is involved in this process. A putative CaM kinase (CaMK) cDNA of C. gloeosporioides was cloned with transcripts from hard-surface-treated conidia. A selective inhibitor of CaMK, KN93 (20 ?M), inhibited (50%) germination and appressorium formation, blocked melanization, and caused the formation of abnormal appressoria. Scytalone, an intermediate in melanin synthesis, reversed the inhibition of melanization but did not restore appressorium formation. The phosphorylation of 18- and 43-kDa proteins induced by hard-surface contact and ethephon was inhibited by the treatment with KN93. These results strongly suggest that hard-surface contact induces Ca2+-calmodulin signaling that primes the conidia to respond to host signals by germination and differentiation into appressoria.

Kim, Yeon-Ki; Li, Daoxin; Kolattukudy, Pappachan E.

1998-01-01

41

Ion channel-forming alamethicin is a potent elicitor of volatile biosynthesis and tendril coiling. Cross talk between jasmonate and salicylate signaling in lima bean.  

PubMed

Alamethicin (ALA), a voltage-gated, ion channel-forming peptide mixture from Trichoderma viride, is a potent elicitor of the biosynthesis of volatile compounds in lima bean (Phaseolus lunatus). Unlike elicitation with jasmonic acid or herbivore damage, the blend of substances emitted comprises only the two homoterpenes, 4,11-dimethylnona-1,3,7-triene and 4,8,12-trimethyltrideca-1,3,7,11-tetraene, and methyl salicylate. Inhibition of octadecanoid signaling by aristolochic acid and phenidone as well as mass spectrometric analysis of endogenous jasmonate demonstrate that ALA induces the biosynthesis of volatile compounds principally via the octadecanoid-signaling pathway (20-fold increase of jasmonic acid). ALA also up-regulates salicylate biosynthesis, and the time course of the production of endogenous salicylate correlates well with the appearance of the methyl ester in the gas phase. The massive up-regulation of the SA-pathway (90-fold) interferes with steps in the biosynthetic pathway downstream of 12-oxophytodienoic acid and thereby reduces the pattern of emitted volatiles to compounds previously shown to be induced by early octadecanoids. ALA also induces tendril coiling in various species like Pisum, Lathyrus, and Bryonia, but the response appears to be independent from octadecanoid biosynthesis, because inhibitors of lipoxygenase and phospholipase A(2) do not prevent the coiling reaction. PMID:11154344

Engelberth, J; Koch, T; Schüler, G; Bachmann, N; Rechtenbach, J; Boland, W

2001-01-01

42

Open form of syntaxin-1A is a more potent inhibitor than wild-type syntaxin-1A of Kv2.1 channels.  

PubMed

We have shown that SNARE (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor) proteins not only participate directly in exocytosis, but also regulate the dominant membrane-repolarizing Kv channels (voltage-gated K+ channels), such as Kv2.1, in pancreatic beta-cells. In a recent report, we demonstrated that WT (wild-type) Syn-1A (syntaxin-1A) inhibits Kv2.1 channel trafficking and gating through binding to the cytoplasmic C-terminus of Kv2.1. During beta-cell exocytosis, Syn-1A converts from a closed form into an open form which reveals its active H3 domain to bind its SNARE partners SNAP-25 (synaptosome-associated protein of 25 kDa) and synaptobrevin. In the present study, we compared the effects of the WT Syn-1A and a mutant open form Syn-1A (L165A, E166A) on Kv2.1 channel trafficking and gating. When co-expressed in HEK-293 cells (human embryonic kidney-293 cells), the open form Syn-1A decreased Kv2.1 current density more than (P<0.05) the WT Syn-1A (166+/-35 and 371+/-93 pA/pF respectively; control=911+/-91 pA/pF). Confocal microscopy and biotinylation experiments showed that both the WT and open form Syn-1A inhibited Kv2.1 expression at the plasma membrane to a similar extent, suggesting that the stronger reduction of Kv2.1 current density by the open form compared with the WT Syn-1A is probably due to a stronger direct inhibition of channel activity. Consistently, dialysis of the recombinant open form Syn-1A protein into Kv2.1-expressing HEK-293 cells caused stronger inhibition of Kv2.1 current amplitude (P<0.05) than the WT Syn-1A protein (73+/-2 and 82+/-3% of the control respectively). We found that the H3 but not H(ABC) domain is the putative active domain of Syn-1A, which bound to and inhibited the Kv2.1 channel. When co-expressed in HEK-293 cells, the open-form Syn-1A slowed down Kv2.1 channel activation (tau=12.3+/-0.8 ms) much more than (P<0.05) WT Syn-1A (tau=7.9+/-0.8 ms; control tau=5.5+/-0.6 ms). In addition, only the open form Syn-1A, but not the WT Syn-1A, caused a significant (P<0.05) left-shift in the steady-state inactivation curve (V(1/2)=33.1+/-1.3 and -29.4+/-1.1 mV respectively; control V(1/2)=-24.8+/-2 mV). The present study therefore indicates that the open form of Syn-1A is more potent than the WT Syn-1A in inhibiting the Kv2.1 channel. Such stronger inhibition by the open form of Syn-1A may limit K+ efflux and thus decelerate membrane repolarization during exocytosis, leading to optimization of insulin release. PMID:15518587

Leung, Yuk M; Kang, Youhou; Xia, Fuzhen; Sheu, Laura; Gao, Xiaodong; Xie, Huanli; Tsushima, Robert G; Gaisano, Herbert Y

2005-04-01

43

Effect of surface mechanical attrition treatment of titanium using alumina balls: surface roughness, contact angle and apatite forming ability  

NASA Astrophysics Data System (ADS)

The effect of surface mechanical attrition treatment (SMAT) of commercially pure titanium (CP-Ti) using 8mm Ø alumina balls was studied. SMAT induced plastic deformation, increased the surface roughness, reduced the grain size and decreased the contact angle (from 64° to 43°) with a corresponding increase in surface energy (from 32 to 53 mJ/m2). Untreated CP-Ti and those treated using alumina balls for 900 s reveals no apatite growth until the 28th day of immersion whereas those treated for 1800 and 2700 s exhibit apatite growth in selective areas and the extent of growth is increased with increase in immersion time in SBF. The study reveals that SMAT using alumina balls is beneficial in imparting the desired surface characteristics, provided the surface contamination is limited, which would otherwise decrease the apatite forming ability.

Jamesh, M.; Sankara Narayanan, T. S. N.; Chu, Paul K.; Park, Il Song; Lee, Min Ho

2013-09-01

44

Staphylococcal ? -toxin: Oligomerization of Hydrophilic Monomers to Form Amphiphilic Hexamers Induced through Contact with Deoxycholate Detergent Micelles  

NASA Astrophysics Data System (ADS)

Native staphylococcus aureus ? -toxin is secreted as a hydrophilic polypeptide chain of Mr 34,000. The presence of deoxycholate above the critical micellar concentration induced the toxin monomers to self-associate, forming ring or cylindrical oligomers. The oligomers were amphiphilic and bound detergent. In deoxycholate solution, the protein-detergent complexes exhibited a sedimentation coefficient of 10.4 S. A Mr of 238,700 was determined by ultracentrifugation analyses at sedimentation equilibrium. Because quantitative detergent-binding studies indicated a protein/detergent ratio of approximately 5:1 (wt/wt), the protein moiety in each protein-detergent complex was determined to be approximately Mr 200 000, corresponding to a hexamer of the native molecule. The amphiphilic toxin hexamers were ultrastructurally indistinguishable from the cytolytic, annular toxin complexes that form on and in biological target membranes. They bound lipid and could be incorporated into artificial lecithin lipid vesicles. The transition of toxin protein molecules from a hydrophilic monomer to an amphiphilic oligomer through self-association has thus been shown to be inducible solely through contact of the native protein molecules with an appropriate amphiphilic substrate.

Bhakdi, Sucharit; Fussle, Roswitha; Tranum-Jensen, Jorgen

1981-09-01

45

Reduction of the secondary structure topological space through direct estimation of the contact energy formed by the secondary structures  

PubMed Central

Background Electron cryomicroscopy is a fast developing technique aiming at the determination of the 3-dimensional structures of large protein complexes. Using this technique, protein density maps can be generated with 6 to 10 Å resolution. At such resolutions, the secondary structure elements such as helices and ?-strands appear to be skeletons and can be computationally detected. However, it is not known which segment of the protein sequence corresponds to which of the skeletons. The topology in this paper refers to the linear order and the directionality of the secondary structures. For a protein with N helices and M strands, there are (N!2N)(M!2M) different topologies, each of which maps N helix segments and M strand segments on the protein sequence to N helix and M strand skeletons. Since the backbone position is not available in the skeleton, each topology of the skeletons corresponds to additional freedom to position the atoms in the skeletons. Results We have developed a method to construct the possible atomic structures for the helix skeletons by sampling the solution space of all the possible topologies of the skeletons. Our method also ranks the possible structures based on the contact energy formed by the secondary structures, rather than the entire chain. If we assume that the backbone atomic positions are known for the skeletons, then the native topology of the secondary structures can be found in the top 30% of the ranked list of all possible topologies for all the 30 proteins tested, and within the top 5% for most of the 30 proteins. Without assuming the backbone location of the skeletons, the possible atomic structures of the skeletons can be constructed using the axis of the skeleton and the sequence segments. The best constructed structure for the skeletons has RMSD to native between 4 and 5 Å for the four tested ?-proteins. These best constructed structures were ranked the 17th, 31st, 16th and 5th respectively for the four proteins out of 32066, 391833, 98755 and 192935 possible assignments in the pool. Conclusion Our work suggested that the direct estimation of the contact energy formed by the secondary structures is quite effective in reducing the topological space to a small subset that includes a near native structure for the skeletons.

Sun, Weitao; He, Jing

2009-01-01

46

Charge and discharge characteristics of a direct contact latent thermal energy storage unit using form-stable high-density polyethylene  

SciTech Connect

For solar thermal energy utilization in relatively low temperatures, a lab-scale direct contact, latent thermal energy storage unit using a form-stable high-density polyethylene (HDPE) was developed. The phase change material (PCM), the form-stable HDPE, does not fluidize nor adhere even after melting, and this particular property permits a direct contact heat transfer between the PCM and a heat transfer fluid (HTF). The storage column in the present study consists of a bundle of vertically arranged thin HDPE rods, where HTF flows in the axial direction and contacts with the HDPE surface directly. A series of experiments were performed for both charge and discharge modes under conditions of different flow rates, initial temperatures in the column, and HTF inlet temperatures. A numerical simulation was also made to study further detailed performance of the storage unit. The charge and discharge characteristics of the storage unit are discussed.

Abe, Y.; Kamimoto, M.; Kanari, K.; Ozawa, T.; Sakamoto, R.; Takahushi, Y.

1984-11-01

47

Oxidized eicosapentaenoic acids more potently reduce LXR?-induced cellular triacylglycerol via suppression of SREBP-1c, PGC-1? and GPA than its intact form  

PubMed Central

Dietary polyunsaturated fatty acids (PUFA), especially eicosapentaenoic acid (EPA), improve lipid metabolism and contribute to the prevention of vascular diseases such as atherosclerosis. However, EPA in the diet is easily oxidized at room temperature and several types of oxidized EPA (OEPA) derivatives are generated. To compare the efficiencies of OEPAs on lipid metabolism with EPA, human hepatocellular liver carcinoma cell line (HepG2) was treated with EPA or OEPAs and their effects on lipid metabolism related genes were studied. OEPAs more potently suppressed the expression of sterol-responsive element-binding protein (SREBP)-1c, a major transcription factor that activates the expression of lipogenic genes, and its downstream target genes than did EPA under conditions of lipid synthesis enhanced by T0901317, a synthetic liver X receptor (LXR) agonist. Furthermore, PGC-1?, a coactivator of both LXR? and SREBP-1, was markedly down-regulated by OEPAs compared with EPA. The treatment of OEPAs also significantly down-regulated the expression of glycerol-3-phosphate acyltransferase (GPA), the initiating enzyme in triacylglycerol (TG) synthesis, more than EPA. Therefore, the advantageous effects of OEPAs on cardiovascular diseases might be due to their SREBP-1c, PGC-1? and GPA mediated ameliorating effects.

2013-01-01

48

Ultrashallow TiC Source\\/Drain Contacts in Diamond MOSFETs Formed by Hydrogenation-Last Approach  

Microsoft Academic Search

Applying the hydrogen (H) radical exposure at the last step of MOSFET fabrication process, an oxygen (O)-terminated channel was converted to a H-terminated one to obtain subsurface hole accumulation for field-effect transistor operation. Low-resistive titanium carbide (TiC) source\\/drain and alumina gate oxide were resistant to the hydrogenation process. The shallow TiC side contacts (~ 3 nm in depth) to the

Yoshikatsu Jingu; Kazuyuki Hirama; Hiroshi Kawarada

2010-01-01

49

Free form source and mask optimization for negative tone resist development for 22nm node contact holes  

NASA Astrophysics Data System (ADS)

In this paper we demonstrate the feasibility of Negative Tone Development (NTD) process to pattern 22nm node contact holes leveraging freeform source and model based assist features. We demonstrate this combined technology with detailed simulation and wafer results. Analysis also includes further improvement achievable using a freeform source compared to a conventional standard source while keeping the mask optimization approaches the same. Similar studies are performed using the Positive Tone Development (PTD) process to demonstrate the benefits of the NTD process.

Coskun, Tamer H.; Dai, Huixiong; Kamat, Vishnu; Hsu, Ching-Mei; Santoro, Gaetano; Ngai, Chris; Reybrouck, Mario; Grozev, Grozdan; Huang, Hsu-Ting

2012-03-01

50

A simple smoothing procedure of 3D surfaces for accurate contact analysis:application to metal forming problems  

Microsoft Academic Search

In most finite element software, it is very convenient to discretise complex obstacles with segments in 2D and facets in 3D.\\u000a It results in C° continuity of the obstacle and consequent discontinuity of its normal, which is at the origin of convergence\\u000a difficulties of algorithms, of numerical oscillations with exaggerated stresses or unjustified loss of contact. Several methods\\u000a have been

L. Fourment; S. Guerdoux

51

The influence of contact conditions on surface reaction layers formed between steel surfaces lubricated by an aviation oil  

Microsoft Academic Search

This study focuses on the influence of load and temperature on the formation and stability of tribo-films for bearing steel on bearing steel contacts lubricated with an aviation oil, EXXON Turbo 2380 (TCP based - tricresyl phosphate) at ambient temperatures. Experiments were carried out on a pin-on-disc (POD) tribometer (with a ball-on-flat geometry) under an average loading rate of 0.17Ns?1

L. Wang; R. J. K. Wood

2007-01-01

52

Direct analytical solution of a modified form of the meshing equations in two dimensions for non-conjugate gear contact  

Microsoft Academic Search

The current technological state-of-the-art utilises modified gear profiles, which are in part non-conjugate and therefore cannot be analysed using standard conjugate contact theory. Existing non-conjugate mathematical models require the solution of a system of implicit equations, typically with significant computational effort and need for careful monitoring of solution stability, convergence and selection of initial values. This paper derives a modified

C. Spitas; V. Spitas

2008-01-01

53

Optimized Ni Oxidation in 80-nm Contact Holes for Integration of Forming-Free and Low-Power Ni\\/NiO\\/Ni Memory Cells  

Microsoft Academic Search

In this brief, we integrate oxygen-deficient NiO cells in 80-nm-wide contact holes using complementary metal-oxide-semiconductor-compatible Ni electrodes. Ni\\/NiO\\/Ni memory-cell arrays are forming free, and can be operated using very low reset current (< 50 muA) and switching voltage (< 1 V). In contrast to metallic-type filaments formed at high-power switching, low-power switching involves high-resistance semiconducting filaments, probably consisting of oxygen-vacancy-rich

Ludovic Goux; Judit G. Lisoni; Xin Peng Wang; Malgorzata Jurczak; Dirk J. Wouters

2009-01-01

54

Co-Assembled Cytotoxic and Pegylated Peptide Amphiphiles Form Filamentous Nanostructures with Potent Anti-Tumor Activity in Models of Breast Cancer  

PubMed Central

Self-assembled peptide amphiphiles (PAs) consisting of hydrophobic, hydrogen bonding, and charged hydrophilic domains form cylindrical nanofibers in physiological conditions and allow for the presentation of a high density of bioactive epitopes on the nanofiber surface. We report here on the use of PAs to form multifunctional nanostructures with tumoricidal activity. The combination of a cationic, membrane-lytic PA co-assembled with a serum-protective, pegylated PA was shown to self-assemble into nanofibers. Addition of the pegylated PA to the nanostructure substantially limited degradation of the cytolytic PA by the protease trypsin, with an eight-fold increase in the amount of intact PA observed after digestion. At the same time, addition of up to 50% pegylated PA to the nanofibers did not decrease the in vitro cytotoxicity of the cytolytic PA. Using a fluorescent tag covalently attached to PA nanofibers we were able to track the biodistribution in plasma and tissues of tumor bearing mice over time after intraperitoneal administration of the nanoscale filaments. Using an orthotopic mouse xenograft model of breast cancer, systemic administration of the cytotoxic pegylated nanostructures significantly reduced tumor cell proliferation and overall tumor growth, demonstrating the potential of multifunctional PA nanostructures as versatile cancer therapeutics.

Toft, Daniel J.; Moyer, Tyson J.; Standley, Stephany M.; Ruff, Yves; Ugolkov, Andrey; Stupp, Samuel I.; Cryns, Vincent L.

2012-01-01

55

Cytogenetic study of the parapatric contact zone between two 46chromosomal forms of the common vole in European Russia  

Microsoft Academic Search

Since the first description of sympatric sibling species and allopatric chromosomal forms of the common vole (Microtus arvalis group) in 1969, the search of their range boundaries has been continually going on up to the present time. Based on the cytogenetic\\u000a material presented in the present study, the geographical distribution of two karyoforms (2n = 46: NF = 84 and

N. Sh. Bulatova; F. N. Golenishchev; Yu. M. Koval’skaya; L. G. Emelyanova; N. V. Bystrakova; S. V. Pavlova; R. S. Nadzhafova; L. A. Lavrechenko

2010-01-01

56

XANES-EXAFS analysis of se solid-phase reaction products formed upon contacting Se(IV) with FeS2 and FeS.  

PubMed

The solid-phase Se speciation after short-term (3 weeks) contact of selenite [Se(IV)] oxyanions with pyrite (FeS2) and troilite (FeS) was investigated using X-ray absorption spectroscopy (XAS; X-ray absorption near-edge spectroscopy-extended X-ray absorption fine structure (XANES-EXAFS)). It was found that the nature of the sulfide mineral dictates the final speciation since respectively Se(0) and FeSe(x) were formed, meaning that the reaction mechanism is different and that these phases cannot be regarded as geochemically similar. The experimental results support the previously proposed sorption/ reduction mechanism for the reaction of selenite with pyrite. In the presence of troilite the reduction proceeds through the intermediate formation of Se(0) by reduction of selenite with dissolved sulfide. XAS data recorded for the FeS2 and FeS were compared with different Se reference phases, ranging in oxidation state from -II to +IV, used for validation of the XAS analysis methodology. This methodology can in principle be used to analyze Se phases formed in "in situ" geochemical conditions such as high-level radioactive waste disposal facilities. PMID:18546695

Breynaert, E; Bruggeman, C; Maes, A

2008-05-15

57

A comparison of barrier type tunnel junction and point contact tunnel junction formed on the same highT c material  

Microsoft Academic Search

By making a combination of both point contact and barrier type tunnel junctions 11 on a single sample of the high Tc superconductor BSCCO (2212) single crystal, we have jy shown that as the tunneling tip is slowly retracted from the surface a point contact junction f gradually evolves from a N-S short to a high resistance tunnel junction. The

H Srikanth; A K Raychaudhuri

1991-01-01

58

The pro-apoptotic Bcl2 family member tBid localizes to mitochondrial contact sites  

Microsoft Academic Search

BACKGROUND: Following cleavage by caspase 8, the C-terminus of Bid translocates from the cytosol to the mitochondria that is dependent upon structures formed by the mitochondrial-specific lipid cardiolipin. Once associated with mitochondria, truncated Bid (tBid) causes the potent release of cytochrome c, endonuclease G, and smac. RESULTS: We investigated whether tBid localizes specifically to the contact sites of mitochondria purported

Michael Lutter; Guy A Perkins; Xiaodong Wang

2001-01-01

59

Contact Information  

Cancer.gov

CONTACT INFORMATION For information about MECC, please contact: Middle East Cancer Consortium Dr. Michael Silbermann, Executive Director P.O. Box 7495 Haifa 31074, Israel Tel: 972-4-8501821 or 972-4-8244794 Fax: 972-4-8524151 or 972-4-8346338 E-mail:

60

Contact electrification  

Microsoft Academic Search

If two materials are brought into contact and then separated they are found to be charged; this is the phenomenon of `contact electrification'. The subject falls naturally into three divisions---electrification of metals by metals; of insulators by metals; and of insulators by insulators. The first of these is well understood; charge transfer between metals is such as to bring the

J. Lowell; A. C. Rose-Innes

1980-01-01

61

Noneczematous Contact Dermatitis  

PubMed Central

Irritant or allergic contact dermatitis usually presents as an eczematous process, clinically characterized by erythematoedematovesicous lesions with intense itching in the acute phase. Such manifestations become erythematous-scaly as the condition progresses to the subacute phase and papular-hyperkeratotic in the chronic phase. Not infrequently, however, contact dermatitis presents with noneczematous features. The reasons underlying this clinical polymorphism lie in the different noxae and contact modalities, as well as in the individual susceptibility and the various targeted cutaneous structures. The most represented forms of non-eczematous contact dermatitis include the erythema multiforme-like, the purpuric, the lichenoid, and the pigmented kinds. These clinical entities must obviously be discerned from the corresponding “pure” dermatitis, which are not associated with contact with exogenous agents.

Foti, Caterina; Vestita, Michelangelo; Angelini, Gianni

2013-01-01

62

Contact Information  

Cancer.gov

Contact Information If you have questions concerning the Sallie Rosen Kaplan Fellowship, please send an email to kaplanfellowship@mail.nih.gov. You may also write to the following address: Center for Cancer TrainingNational Cancer Institute9609 Medical

63

Contact Us  

Center for Drug Evaluation (CDER)

... Contact Us. Have a comment/question about pharmacy compounding? Please send an e-mail to Compounding@fda.hhs.gov. -. -. ... More results from www.fda.gov/drugs/guidancecomplianceregulatoryinformation/pharmacycompounding

64

Highly potent silver-organoalkoxysilane antimicrobial porous nanomembrane.  

PubMed

We used a simple electrospinning technique to fabricate a highly potent silver-organoalkoxysilane antimicrobial composite from AgNO3-polyvinylpyrrolidone (PVP)/3-aminopropyltrimethoxysilane (APTMS)/tetraethoxysilane (TEOS) solution. Spectroscopic and microscopic analyses of the composite showed that the fibers contain an organoalkoxysilane 'skeleton,' 0.18 molecules/nm2 surface amino groups, and highly dispersed and uniformly distributed silver nanoparticles (5 nm in size). Incorporation of organoalkoxysilanes is highly beneficial to the antimicrobial mat as (1) amino groups of APTMS are adhesive and biocidal to microorganisms, (2) polycondensation of APTMS and TEOS increases the membrane's surface area by forming silicon bonds that stabilize fibers and form a composite mat with membranous structure and high porosity, and (3) the organoalkoxysilanes are also instrumental to the synthesis of the very small-sized and highly dispersed silver metal particles in the fiber mat. Antimicrobial property of the composite was evaluated by disk diffusion, minimum inhibition concentration (MIC), kinetic, and extended use assays on bacteria (Escherichia coli, Bacillus anthracis, Staphylococcus aureus, and Brucella suis), a fungus (Aspergillus niger), and the Newcastle disease virus. The membrane shows quick and sustained broad-spectrum antimicrobial activity. Only 0.3 mg of fibers is required to achieve MIC against all the test organisms. Bacteria are inhibited within 30 min of contact, and the fibers can be used repeatedly. The composite is silver efficient and environment friendly, and its membranous structure is suitable for many practical applications as in air filters, antimicrobial linen, coatings, bioadhesives, and biofilms. PMID:23574791

Umar, Sirajo; Liu, Yuanfeng; Wu, Yiguang; Li, Guangtao; Ding, Jiabo; Xiong, Runsong; Chen, Jinchun

2013-04-10

65

Free form fabricated features on CoCr implants with and without hydroxyapatite coating in vivo: a comparative study of bone contact and bone growth induction  

Microsoft Academic Search

The current study evaluates the in vivo response to free form fabricated cobalt chromium (CoCr) implants with and without\\u000a hydroxyapatite (HA) plasma sprayed coatings. The free form fabrication method allowed for integration of complicated pyramidal\\u000a surface structures on the cylindrical implant. Implants were press fit into the tibial metaphysis of nine New Zealand white\\u000a rabbits. Animals were sacrificed and implants

Anders Palmquist; Stéphane Gonçalves; Andy Taylor; Mark Taylor; Lena Emanuelsson; Peter Thomsen; Håkan Engqvist

2011-01-01

66

Contact-based sequence alignment  

PubMed Central

This paper introduces the novel method of contact-based protein sequence alignment, where structural information in the form of contact mutation probabilities is incorporated into an alignment routine using contact-mutation matrices (CAO: Contact Accepted mutatiOn). The contact-based alignment routine optimizes the score of matched contacts, which involves four (two per contact) instead of two residues per match in pairwise alignments. The first contact refers to a real side-chain contact in a template sequence with known structure, and the second contact is the equivalent putative contact of a homologous query sequence with unknown structure. An algorithm has been devised to perform a pairwise sequence alignment based on contact information. The contact scores were combined with PAM-type (Point Accepted Mutation) substitution scores after parameterization of gap penalties and score weights by means of a genetic algorithm. We show that owing to the structural information contained in the CAO matrices, significantly improved alignments of distantly related sequences can be obtained. This has allowed us to annotate eight putative Drosophila IGF sequences. Contact-based sequence alignment should therefore prove useful in comparative modelling and fold recognition.

Kleinjung, Jens; Romein, John; Lin, Kuang; Heringa, Jaap

2004-01-01

67

Contact Mechanics  

NASA Astrophysics Data System (ADS)

This book describes the stresses and deformations of solid bodies in contact with each other, along curved surfaces that touch initially at a point of contact or along a line. Examples are a railroad track and the wheels running on it, or a pair of meshed gear teeth. The book commences with the development of the theory since the problem was first described in 1882. There is also a discussion of the influence of friction and the topographical roughness of surfaces. An important feature of the book is the treatment of plastic and viscoelastic bodies, and an appreciable section of the book discusses bodies in sliding or rolling contact. The mathematical treatment assumes that users of the book are graduates in engineering; it is a book written by a distinguished engineer for other professionals and their graduate students.

Johnson, K. L.

1987-08-01

68

Electrical contacts to ultrananocrystalline diamond.  

SciTech Connect

The contact behavior of various metals on n-type nitrogen-doped ultrananocrystalline diamond (UNCD) thin films has been investigated. The influences of the following parameters on the current-voltage characteristics of the contacts are presented: (1) electronegativity and work function of various metals, (2) an oxidizing acid surface cleaning step, and (3) oxide formation at the film/contact interface. Near-ideal ohmic contacts are formed in every case, while Schottky barrier contacts prove more elusive. These results counter most work discussed to date on thin diamond films, and are discussed in the context of the unique grain-boundary conductivity mechanism of the nitrogen-doped UNCD.

Gerbi, J. E.; Auciello, O.; Birrell, J.; Gruen, D. M.; Carlisle, J. A.; Alphenaar, B. W.; Materials Science Division; Univ. of Louisville

2003-09-08

69

Contacts to ZnO  

Microsoft Academic Search

A review is given of Ohmic and Schottky contacts to n- and p-type ZnO. It is relatively straightforward to form high-quality Ohmic contacts to n-type ZnO, with specific contacts resistivity in the range 10?6?cm2 even for unnannealed contacts on strongly n-type layers, while recent work has also shown good results (10?5–10?6?cm2) for Au or Ni\\/Au annealed at 300–600°C. Schottky contacts

K. Ip; G. T. Thaler; Hyucksoo Yang; Sang Youn Han; Yuanjie Li; D. P. Norton; S. J. Pearton; Soowhan Jang; F. Ren

2006-01-01

70

Multiple clusters of release sites formed by individual thalamic afferents onto cortical interneurons ensure reliable transmission  

PubMed Central

Summary Thalamic afferents supply the cortex with sensory information by contacting both excitatory neurons and inhibitory interneurons. Interestingly, thalamic contacts with interneurons constitute such a powerful synapse that even one afferent can fire interneurons, thereby driving feedforward inhibition. However, the spatial representation of this potent synapse on interneuron dendrites is poorly understood. Using Ca imaging and electron microscopy we show that an individual thalamic afferent forms multiple contacts with the interneuronal proximal dendritic arbor, preferentially near branch points. More contacts are correlated with larger amplitude synaptic responses. Each contact, consisting of a single bouton, can release up to 7 vesicles simultaneously, resulting in graded and reliable Ca transients. Computational modeling indicates that the release of multiple vesicles at each contact minimally reduces the efficiency of the thalamic afferent in exciting the interneuron. This strategy preserves the spatial representation of thalamocortical inputs across the dendritic arbor over a wide range of release conditions.

Bagnall, Martha W.; Hull, Court; Bushong, Eric A.; Ellisman, Mark H.; Scanziani, Massimo

2012-01-01

71

Contact hysteroscopy.  

PubMed

In 1907 innovations in optics and illumination made by Maximilian Nitze were applied to hysteroscopy by Charles David, who wrote a treatise of hysteroscopy. David improved illumination by placing an electric incandescent bulb at the intrauterine end of his endoscope and also sealed the distal end of the tube with a piece of glass. The history of the contact endoscope that the authors personally used is connected to the invention by Vulmiere (1952) of a revolutionary illumination process in endoscopy--the "cold light" process. The components of cold light consist of a powerful external light source that is transmitted via a special optical guide into the endometrial cavity. The 1st application of his principle (1963) was an optical trochar contained in a metallic sheath. This simple endoscope was perfected, and in 1973 Barbot and Parent, in France, began to use it to examine the uterine cavity. Discussion focuses on methods, instrumentation, method for examination (grasping the instrument, setup, light source, anesthesia, dilatation, technique, and normal endometrium); cervical neoplasia; nonneoplastic lesions of the endometrium (endometrial polyp, submucous myoma, endometrial hyperplasia); intrauterine device localization; neoplastic lesions of the endometrium; precursors (adenocarcinoma); hysteroscopy in pregnancy (embryoscopy, hydatidiform mole, postpartum hemorrhage, incomplete abortion, spontaneous abortion, induced abortions, and amnioscopy); and examinations of children and infants. The contact endoscope must make light contact with the structure to be viewed. The principles of contact endoscopy depend on an interpretation of color, contour, vascular pattern, and a sense of touch. These are computed together and a diagnosis is made on the basis of previously learned clinical pathologic correlations. The contact endoscope is composed of 3 parts: an optical guide; a cylindric chamber that collects and traps ambient light; and a magnifying eyepiece. The phase of the menstrual cycle may be identified on the basis of the endometrial pattern. This pattern diagnosis is dependent on color, contour, and physical adhesiveness of the tissue. Cervical intraepithelial neoplasia (CIN) is the most common neoplastic lesion of the cervix. When atypical epithelium extends into the cervical canal beyond the view of the colposcope, the 6 mm contact hysteroscope has been helpful in determining the extent and severity of the lesion as well as to direct biopsy equipment to the site of the pathologic condition. PMID:6602024

Baggish, M S; Barbot, J

1983-06-01

72

Dynamic Contact Stiffness of Adhesive Hertzian Contact  

Microsoft Academic Search

Based on the JKR and DMT models, dynamic contact stiffness of a rigid sphere against an adhesive semiinfinite solid is investigated by the consideration of dynamic contact deformation at the contact interface. The assumption of sufficiently small oscillating force yields a dynamic contact-pressure distribution of constant contact size, and then dynamic contact stiffness. It is found that except for the

Jiayong Tian

2011-01-01

73

Medicare: Helpful Contacts  

MedlinePLUS

... are here: Home . Contacts Home Share Medicare Helpful Contacts Find Helpful Contacts for Organizations This Helpful Contacts tool will provide ... and learn more about related websites Download Helpful Contacts Database You have the option of downloading the ...

74

Adhesion Effects in Viscoelastic Contacts  

NASA Astrophysics Data System (ADS)

The dynamic formation and rupture of small contacts to viscoelastic materials is not well understood, partly because of the lack of a complete theoretical model that includes the history dependent interplay between adhesion, long range creep, interface fracture, and plastic deformation. We describe experimental studies of dynamic contacts between a Berkovich diamond probe and latex films. Contacts were formed at both constant load and constant loading rate. Total contact times ranged between 10ms to 1000 s. Maximum loads were up to a few hundred micro-Newtons. We will discuss the various limiting regimes and the extraction of important physical quantities such as work of adhesion, stress intensity factor, and creep compliance.

Giri, M.; Bousfield, D.; Unertl, W. N.

2000-03-01

75

Reducing contact resistance in graphene devices through contact area patterning.  

PubMed

Performance of graphene electronics is limited by contact resistance associated with the metal-graphene (M-G) interface, where unique transport challenges arise as carriers are injected from a 3D metal into a 2D-graphene sheet. In this work, enhanced carrier injection is experimentally achieved in graphene devices by forming cuts in the graphene within the contact regions. These cuts are oriented normal to the channel and facilitate bonding between the contact metal and carbon atoms at the graphene cut edges, reproducibly maximizing "edge-contacted" injection. Despite the reduction in M-G contact area caused by these cuts, we find that a 32% reduction in contact resistance results in Cu-contacted, two-terminal devices, while a 22% reduction is achieved for top-gated graphene transistors with Pd contacts as compared to conventionally fabricated devices. The crucial role of contact annealing to facilitate this improvement is also elucidated. This simple approach provides a reliable and reproducible means of lowering contact resistance in graphene devices to bolster performance. Importantly, this enhancement requires no additional processing steps. PMID:23473291

Smith, Joshua T; Franklin, Aaron D; Farmer, Damon B; Dimitrakopoulos, Christos D

2013-03-08

76

Contact lens correction of presbyopia.  

PubMed

The contact lens wearing presbyopic population is underserved worldwide. There are several available options, including single vision contact lenses and spectacle over-correction for near, monovision, rigid gas permeable (GP) multifocal and bifocal lens designs and soft bifocal lens designs. This paper presents an overview of the latest research and clinical experience as it pertains to these forms of correction. Recent comparative studies concluded that contact lens multifocals perform better in many different forms of visual measurements, in some cases performing similar to best spectacle correction, than monovision wearers. The future appears to be very promising for multifocal GP and soft lens modalities. PMID:18201225

Bennett, Edward S

2008-01-08

77

Determining a Surrogate Contact Pair in a Hertzian Contact Problem  

PubMed Central

Laboratory testing of contact phenomena can be prohibitively expensive if the interacting bodies are geometrically complicated. This work demonstrates means to mitigate such problems by exploiting the established observation that two geometrically dissimilar contact pairs may exhibit the same contact mechanics. Specific formulas are derived that allow a complicated Hertzian contact pair to be replaced with an inexpensively manufactured and more easily fixtured surrogate pair, consisting of a plane and a spheroid, which has the same (to second-order accuracy) contact area and pressure distribution as the original complicated geometry. This observation is elucidated by using direct tensor notation to review a key assertion in Hertzian theory; namely, geometrically complicated contacting surfaces can be described to second-order accuracy as contacting ellipsoids. The surrogate spheroid geometry is found via spectral decomposition of the original pair’s combined Hessian tensor. Some numerical examples using free-form surfaces illustrate the theory, and a laboratory test validates the theory under a common scenario of normally compressed convex surfaces. This theory for a Hertzian contact substitution may be useful in simplifying the contact, wear, or impact testing of complicated components or of their constituent materials.

Sanders, Anthony P.; Brannon, Rebecca M.

2013-01-01

78

Flavoxate, a potent phosphodiesterase inhibitor.  

PubMed

The c-AMP phosphodiesterase inhibiting properties of flavoxate and of its main metabolite i.e. 3-methylflavone-8-carboxylic acid (MFCA), were assayed in vitro and compared to those of theophylline. Flavoxate and MFCA are competitive phosphodiesterase inhibitors, and are 21 and respectively 5 times more potent than theophylline. The smooth muscle relaxing activity of flavoxate possibly relies on this enzymatic mechanism. PMID:167667

Conti, M; Setnikar, I

1975-02-01

79

CRCHD - PNP Contact  

Cancer.gov

CRCHD - PNP Contact  Back to CRCHD Ongoing Research PNP Contact PNP Contact For questions about the Patient Navigation Programs contact: Roland Garcia, Ph.D.| PNP Project Leader Center to Reduce Cancer Health Disparities National Cancer Institute 6116

80

Optimization of protease-inhibitor interactions by randomizing adventitious contacts.  

PubMed

Polypeptide protease inhibitors are often found to inhibit targets with which they did not coevolve, as in the case of high-affinity inhibition of bacterial subtilisin by the leech inhibitor eglin c. Two kinds of contacts exist in such complexes: (i) reactive site loop-active site contacts and (ii) interactions outside of these that form the broader enzyme-inhibitor interface. We hypothesized that the second class of "adventitious" contacts could be optimized to generate significant increases in affinity for a target enzyme or discrimination of an inhibitor for closely related target proteases. We began with a modified eglin c, Arg-42-Arg-45-eglin, in which the reactive site loop had been optimized for subtilisin-related processing proteases of the Kex2/furin family. We randomized 10 potential adventitious contact residues and screened for inhibition of soluble human furin. Substitutions at one of these sites, Y49, were also screened against yeast Kex2 and human PC7. These screens identified not only variants that exhibited increased affinity (up to 20-fold), but also species that exhibited enhanced selectivity, that is, increased discrimination between the target enzymes (up to 41-fold for furin versus PC7 and 20-fold for PC7 versus furin). One variant, Asp-49-Arg-42-Arg-45-eglin, exhibited a Ki of 310 pM for furin and blocked furin-dependent processing of von Willebrand factor in COS-1 cells when added to the culture medium of the cells. The exploitation of adventitious contact sites may provide a versatile technique for developing potent, selective inhibitors for newly discovered proteases and could in principle be applied to optimize numerous protein-protein interactions. PMID:12832612

Komiyama, Tomoko; VanderLugt, Bryan; Fugère, Martin; Day, Robert; Kaufman, Randal J; Fuller, Robert S

2003-06-27

81

Celebrity Patients, VIPs, and Potentates  

PubMed Central

Background: During the second half of the 20th century, the literature on the doctor-patient relationship mainly dealt with the management of “difficult” (personality-disordered) patients. Similar problems, however, surround other types of “special” patients. Method: An overview and analysis of the literature were conducted. As a result, such patients can be subcategorized by their main presentations; each requires a specific management strategy. Results: Three types of “special” patients stir up irrational feelings in their caregivers. Sick celebrities threaten to focus public scrutiny on the private world of medical caregivers. VIPs generate awe in caregivers, with loss of the objectivity essential to the practice of scientific medicine. Potentates unearth narcissism in the caregiver-patient relationship, which triggers a struggle between power and shame. Pride, privacy, and the staff's need to be in control are all threatened by introduction of the special patient into medicine's closed culture. Conclusion: The privacy that is owed to sick celebrities should be extended to protect overexposed staff. The awe and loss of medical objectivity that VIPs generate are counteracted by team leadership dedicated to avoiding any deviation from standard clinical procedure. Moreover, the collective ill will surrounding potentates can be neutralized by reassuring them that they are “special”—and by caregivers mending their own vulnerable self-esteem.

Groves, James E.; Dunderdale, Barbara A.; Stern, Theodore A.

2002-01-01

82

Multipotent neural precursors express neural and hematopoietic factors, and enhance ex vivo expansion of cord blood CD34+ cells, colony forming units and NOD/SCID-repopulating cells in contact and noncontact cultures.  

PubMed

In view of the possible crosstalks between hematopoiesis and neuropoiesis, we evaluated two microenvironments, murine neonatal neural cell line C17.2 and primary embryonic aorta-gonad-mesonephros (AGM) stromal cells, on the ex vivo expansion of CD34+ cells from human cord blood. In a contact culture system, C17.2 or AGM cells significantly enhanced the expansion of CD34+ cells to a panel of early and committed hematopoietic progenitor cells. In a noncontact transwell system, pre-established C17.2 cells significantly increased the expansion of total nucleated cells, CD34+ cells and multilineage colony forming cells (P<0.01). Expanded cells were infused into nonobese diabetic/severe-combined immunodeficient mice. The engraftment of human (hu)CD45+ cells in the bone marrow of these mice was consistently higher in all the 10 experiments conducted with the support of C17.2 cells when compared with those in respective control groups (11.9 vs 2.43%, P=0.03). Using RT-PCR and Southern blot analysis, we showed that AGM and C17.2 cells expressed a panel of hematopoietic, bone morphogenetic and neurotrophic factors. Our data provided the first evidence on the promoting effects of a neural progenitor cell line on hematopoiesis at a noncontact condition. The mechanism could be mediated by the expression of multilineage regulatory factors. PMID:15496976

Li, K; Lee, S M; Su, R J; Zhang, X B; Yuen, P M P; Li, C K; Yang, M; Tsang, K S; James, A E; Tse, Y H J; Ng, L Y W; Fok, T F

2005-01-01

83

Thermal Contact Conductance at Low Contact Pressures  

Microsoft Academic Search

New correlations are presented for the truncated Gaussian (TG) thermal contact conductance model during first loading. The TG model is also incorporated into existing models for the hysteresis effect of thermal contact conductance and for the plastic contact pressure. The TG models, as well as the existing fully Gaussian models, are compared against new experimental data collected at very low

Fernando H. Milanez; Marcia B. H. Mantelli; Michael Yovanovich

2004-01-01

84

Buying Cosmetic Contact Lenses?  

MedlinePLUS

... Getting Your Prescription Should Be Easy What Are Cosmetic Contacts? Whether you're planning to cap off ... color from blue to violet for the day, cosmetic contactscontact lenses meant to change the way ...

85

Contact Lens Solution Toxicity  

MedlinePLUS

... are many different types of solutions used with contact lenses, and all can cause a toxic reaction. Such ... with the fit and the comfort of their contact lenses are at greater risk of contact lens solution ...

86

Highly potent aminopyridines as Syk kinase inhibitors.  

PubMed

A novel class of potent Syk inhibitors has been developed from rational design. Highly potent aminopyridine derivatives bearing a 4-trifluoromethyl-2-pyridyl motif and represented by compound 13b IC(50): 0.6 nM were identified. Substitution by a 2-pyrazinyl motif and SAR expansion in position 4 of the central core provided diverse potent non-cytotoxic Syk inhibitors showing nanomolar activity inhibiting human mast cell line LAD2 degranulation. PMID:22877633

Castillo, Marcos; Forns, Pilar; Erra, Montse; Mir, Marta; López, Manel; Maldonado, Mónica; Orellana, Adelina; Carreño, Cristina; Ramis, Isabel; Miralpeix, Montserrat; Vidal, Bernat

2012-07-20

87

Mechanisms in contact dermatitis  

Microsoft Academic Search

Contact dermatitis is one of the most frequently presenting problems of patients seen in dermatology clinics and a common dermatosis seen in industry. Contact dermatitis may be allergic or, more commonly, irritant in nature. Irritant contact dermatitis is a nonimmunologic reaction to environmental chemicals, in which direct skin damage occurs after one or more exposures. Allergic contact dermatitis is a

Elizabeth A. Abel; Gary S. Wood

1986-01-01

88

The Parasocial Contact Hypothesis  

Microsoft Academic Search

We propose a communication analogue to Allport's (1954) Contact Hypothesis called the Parasocial Contact Hypothesis (PCH). If people process mass-mediated parasocial interaction in a manner similar to interpersonal interaction, then the socially beneficial functions of intergroup contact may result from parasocial contact. We describe and test the PCH with respect to majority group members' level of prejudice in three studies,

Edward Schiappa; Peter B. Gregg; Dean E. Hewes

2005-01-01

89

On the nature of tribological contact in automotive brakes  

Microsoft Academic Search

The tribological contact in automotive brakes involves dry sliding contact at high speeds and high contact forces. The commonly used organic binder-type brake pad friction materials are extremely inhomogeneous and exhibit very low bulk strengths. Despite the low strength, the specific contact surfaces that form during the use render the pads very good friction and wear characteristics. This paper gives

Mikael Eriksson; Filip Bergman; Staffan Jacobson

2002-01-01

90

Allergic contact dermatitis due to a herbicide (barban).  

PubMed Central

Canadian farmers are using increasing amounts of herbicides. Often they do not use adequate skin protection. Two cases of severe allergic contact dermatitis due to the herbicide barban are described. Patch testing with various substances, including barban, confirmed the diagnosis. Sensitization studies in guinea pigs and in one of the authors showed that barban is a potent sensitizer. It is recommended that if skin contact with barban occurs the skin be washed immediately with soap and water. Images Fig. 1

Hogan, D J; Lane, P R

1985-01-01

91

Recordkeeping and contact lens practice.  

PubMed

Recordkeeping in contact lens practice may be based on a problem-oriented system that emphasizes the use of forms. Fitting agreements and informed consent agreements are the most important components of such a system. Progress notes are also used to document the episodic care that is an integral part of contact lens practice. Examination findings should be described with descriptive language whenever possible; warnings, diagnoses, patient management, and recall and referral appointments should be conscientiously documented in the record of care. PMID:7812068

Classé, J G

1994-01-01

92

Contact Lenses for Vision Correction  

MedlinePLUS

... Health News Consumer Alerts Contact Lenses for Vision Correction Tweet What are contacts? Contact lenses are thin, ... to see close up). Contact Lenses for Vision Correction Contact Lens Types Important Things to Know About ...

93

Screen printed interdigitated back contact solar cell  

NASA Astrophysics Data System (ADS)

Interdigitated back contact solar cells are made by screen printing dopant materials onto the back surface of a semiconductor substrate in a pair of interdigitated patterns. These dopant materials are then diffused into the substrate to form junctions having configurations corresponding to these patterns. Contacts having configurations which match the patterns are then applied over the junctions.

Baraona, C. R.; Mazaris, G. A.; Chai, A. T.

1984-10-01

94

How do contact systems affect regional development?  

Microsoft Academic Search

The paper reports on theoretical and empirical studies of contact systems. It refines and extends the framework, and consequently the implications, of such systems. This framework forms a base for extensive empirical studies, the results of which are used to suggest how contact systems are resolved and how they affect the quantitative and qualitative aspects of regional development. The analysis

B Thorngren

1970-01-01

95

Avoiding Cross-Contact  

MedlinePLUS

Avoiding Cross-Contact Understanding the difference between Cross-Contamination vs. Cross-Contact When dining at a restaurant, you will need to ... explain the difference to them. Examples of Cross-Contact and How to Avoid It A knife that ...

96

CONTACT URTICARIA: PRESENT SCENARIO  

PubMed Central

Immunological contact urticaria is a hypersensitivity reaction that appears on the skin following contact with an eliciting substance. Recent advances in our understanding of the molecular mechanism and pathogenesis of this reaction have altered its classification, diagnosis, and treatment. We discuss classification, epidemiology, diagnosis, testing, and treatment options that are available to patients with contact urticaria.

Bhatia, Ruchi; Alikhan, Ali; Maibach, Howard I

2009-01-01

97

Contact lens in keratoconus.  

PubMed

Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL. PMID:23925325

Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

2013-08-01

98

Contact lens in keratoconus  

PubMed Central

Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL.

Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

2013-01-01

99

beta Endorphin is a Potent Analgesic Agent  

Microsoft Academic Search

beta -Endorphin, an opiate-like peptide, has potent antinociceptive properties when it is administered directly into the brain and assayed in the tail-flick, hot-plate, and writhing tests in mice and in the wet shake test in rats. On a molar basis, beta -endorphin is 18 to 33 times more potent than morphine and its actions are blocked by the specific opiate

Horace H. Loh; L. F. Tseng; Eddie Wei; Choh Hao Li

1976-01-01

100

Screen Printed Interdigitated Back Contact Solar Cell.  

National Technical Information Service (NTIS)

Interdigitated back contact solar cells were made by screen printing dopant materials onto the back surface of a semiconductor substrate in a pair of interdigitated patterns. These dopant materials were then diffused into the substrate to form junctions h...

C. R. Baraona G. A. Mazaris A. T. Chai

1983-01-01

101

Environmental Decision Memo for Food Contact Notification ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... formed meat and poultry products. Notifier: FMC Corp. 1735 Market St. Philadelphia, PA 19103. To: Division of Food Contact ... More results from www.fda.gov/food/ingredientspackaginglabeling/environmentaldecisions

102

Multipotent neural precursors express neural and hematopoietic factors, and enhance ex vivo expansion of cord blood CD34+ cells, colony forming units and NOD\\/SCID-repopulating cells in contact and noncontact cultures  

Microsoft Academic Search

In view of the possible crosstalks between hematopoiesis and neuropoiesis, we evaluated two microenvironments, murine neonatal neural cell line C17.2 and primary embryonic aorta–gonad–mesonephros (AGM) stromal cells, on the ex vivo expansion of CD34+ cells from human cord blood. In a contact culture system, C17.2 or AGM cells significantly enhanced the expansion of CD34+ cells to a panel of early

K Li; S M Lee; R J Su; X B Zhang; P M P Yuen; C K Li; M Yang; K S Tsang; A E James; Y H J Tse; L Y W Ng; T F Fok

2005-01-01

103

Non-contact measurement of contact wire  

NASA Astrophysics Data System (ADS)

The overhead contact system is the power supply unit of the electric locomotive. This article is to introduce our newly developed method to measure the height and pull out value of the contact wire. A carema dolly which can move on railway is applied to bear the weight of the measure equipment; two linear CCD cameras are installed on the dolly symmetrically about the midline of two rails. While the dolly move along the railway, two CCD cameras grasp the image synchronously, and a computer real-time process the images, the height and pull out value can be calculate out from the images.

Yi, Yaxing; Ye, Xuemei; Li, Zhongke; Yue, Kaiduan

2008-12-01

104

Noneczematous Contact Reactions  

Microsoft Academic Search

\\u000a Not all skin contact reactions present as eczema or dermatitis. There are several distinct noneczematous contact reactions\\u000a which are more commonly seen. The mechanisms of these reactions are not clearly elucidated yet. It is very useful to clinicians\\u000a to be able to identify these dermatoses as contact reactions so that they may be confirmed with patch testing and other unnecessary

Anthony Goon; Chee-Leok Goh

105

Gluing tight contact structures  

Microsoft Academic Search

We prove gluing theorems for tight contact structures. As special\\u000acases, we rederive gluing theorems due to V. Colin and\\u000aS. Makar-Limanov and present an algorithm for determining whether a\\u000agiven contact structure on a handlebody is tight. As applications, we\\u000aconstruct a tight contact structure on a genus $4$ handlebody which\\u000abecomes overtwisted after Legendrian $-1$ surgery and study

Ko Honda

2002-01-01

106

Protein Contact Dermatitis  

Microsoft Academic Search

\\u000a Protein contact with the skin can be associated with two major clinical conditions: immunological contact urticaria (ICU)\\u000a and protein contact dermatitis (PCD), of which the latter will be discussed here. This chapter reviews the pathogenesis, clinical\\u000a pictures and the causal proteins, most of which are responsible for occupation-related skin problems, i.e. fruits, vegetables,\\u000a spices, plants and woods, animal proteins, grains

An Goossens; Cristina Amaro

107

Contact Cheilitis – A Review  

Microsoft Academic Search

Contact dermatitis is a common cause of eczematous cheilitis. In a Singapore series, allergic contact dermatitis is commoner than irritant contact dermatitis. More females are affected than males. Eczematous cheilitis usually presents in the 3rd and 4th decades of life. Eczematous cheilitis tends to occur among office workers and professionals (50.5%). This is probably due to the more frequent use

C. L. Goh

2003-01-01

108

Drug Interaction: Contact Information  

Center for Drug Evaluation (CDER)

... Development Resources. Section Contents Menu. Development & Approval Process (Drugs). ... Drug Interaction: Contact Information. ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

109

Amorphous Ge bipolar blocking contacts on Ge detectors  

SciTech Connect

Semiconductor nuclear radiation detectors are usually operated in a full depletion mode and blocking contacts are required to maintain low leakage currents and high electric fields for charge collection. Blocking contacts on Ge detectors typically consist of n-type contacts formed by lithium diffusion and p-type contacts formed by boron ion implantation. Electrical contacts formed using sputtered amorphous Ge (a-Ge) films on high-purity Ge crystals were found to exhibit good blocking behavior in both polarities with low leakage currents. The a-Ge contacts have thin dead layers associated with them and can be used in place of lithium-diffused, ion-implanted or Schottky barrier contacts on Ge radiation detectors. Multi-electrode detectors can be fabricated with very simple processing steps using these contacts. 12 refs.

Luke, P.N.; Cork, C.P.; Madden, N.W.; Rossington, C.S.; Wesela, M.F.

1991-10-01

110

Allergic contact dermatitis from temporary henna tattoo.  

PubMed

Temporary henna tattooing has been very popular during recent years. Henna (Lawsonia inermis) is a plant from the Lythraceae family. For henna tattooing, henna dye is used. It is a dark green powder, made from the leaves of the plant, used for hair dyeing and body tattooing. Very often, para-phenylenediamine (PPD) is added to henna dye to make color blacker and to speed up dyeing. PPD may be a very potent contact sensitizer. We report a 9-year-old boy with allergic contact dermatitis due to temporary henna tattooing. Patch testing showed a positive reaction to PPD. After the treatment with topical corticosteroid and oral antihistamines, the lesion cleared with discrete residual hypopigmentation. PMID:19207440

Jovanovic, Dragan L; Slavkovic-Jovanovic, Maja R

2009-01-01

111

76 FR 33031 - Agency Information Collection (Request for Contact Information) Activity Under OMB Review  

Federal Register 2010, 2011, 2012, 2013

...Agency Information Collection (Request for Contact Information) Activity Under OMB Review...correspondence. FOR FURTHER INFORMATION CONTACT: Denise McLamb, Enterprise Records Service...SUPPLEMENTARY INFORMATION: Title: Request for Contact Information, VA Form 21-30. OMB...

2011-06-07

112

Enhancing Intergenerational Contact.  

ERIC Educational Resources Information Center

This document is a curriculum module designed to assist secondary school home economic teachers in teaching students about aging. The three major purposes of this module are to provide data-based information on aging related to needs of students to enhance intergenerational contact; to facilitate the expansion of intergenerational contacts by…

Ralston, Penny A.; And Others

113

Language Contact: An Introduction.  

ERIC Educational Resources Information Center

This book surveys situations in which language contact arises and focuses on what happens to the languages themselves: sometimes nothing, sometimes the incorporation of new words, sometimes the spread of new sounds and sentence structures across many languages and wide swathes of territory. It outlines the origins and results of contact-induced…

Thomason, Sarah G.

114

Impact of defect distribution on transport properties for Au/ZnO Schottky contacts formed with H2O2-treated unintentionally doped n-type ZnO epilayers  

NASA Astrophysics Data System (ADS)

The Au/ZnO Schottky contacts fabricated using H2O2-treated unintentionally doped ZnO epilayers showed an abnormal behavior in their transport properties; i.e., the background carrier density-dependent trade-off relation between the barrier height and the ideality factor was observed. This result is attributed to the difference in carrier transport mechanisms for each sample fabricated using ZnO epilayers with different background carrier concentrations; namely, the observed trade-off relation originates from a result that the difference in the distribution of oxygen vacancies near the surface and depletion regions, which depends on the initial background carrier concentration of each sample, causes the different carrier transport mechanism.

Lee, Sejoon; Lee, Youngmin; Kim, Deuk Young; Won Kang, Tae

2010-04-01

115

Contact and non-contact type Hamiltonian systems generated by second-order Lagrangians  

Microsoft Academic Search

We showthatsomeverynaturallyoccurringenergymanifoldsthatareinducedby second-order Lagrangians L = L(u, u? ,u ?? ) are not, in general, of contact type in (R4 ,? ). We also comment on the more general question whether there exist any contact forms on these energy manifolds for which the associated Reeb vector field coincides with the Hamiltonian vector field.

S. B. ANGENENT; J. B. VAN DEN BERG; R. C. A. M. VANDERVORST

2007-01-01

116

Conformal quaternionic contact curvature and the local sphere theorem  

Microsoft Academic Search

A tensor invariant is defined on a quaternionic contact manifold in terms of the curvature and torsion of the Biquard connection involving derivatives up to third order of the contact form. This tensor, called quaternionic contact conformal curvature, is similar to the Weyl conformal curvature in Riemannian geometry and to the Chern–Moser tensor in CR geometry. It is shown that

Stefan Ivanov; Dimiter Vassilev

2010-01-01

117

Coatings tribology—contact mechanisms and surface design  

Microsoft Academic Search

The fundamentals of coating tribology are presented by using a generalised holistic approach to the friction and wear mechanisms of coated surfaces in dry sliding contacts. It is based on a classification of the tribological contact process into macromechanical, micromechanical, nanomechanical and tribochemical contact mechanisms, and material transfer. The important influence of thin tribo- and transfer layers formed during the

Kenneth Holmberg; Allan Matthews; Helena Ronkainen

1998-01-01

118

Contact Mechanisms and Contact Resistance Characteristics of Solid Tin and Plated Tin Contacts Used for Connectors  

Microsoft Academic Search

Tin and its alloys have been applied for the plating of electrical contacts for low electrical power conditions. In particular, tin-plated contacts are widely used as connector contacts in automotive applications and as make-break contacts in keyboard switches. In the relationship between contact resistance (R) and contact load (W) for both solid and plated tin, singularities have been found. Previously

Terutaka Tamai; Shigeru Sawada; Yasuhiro Hattori

2010-01-01

119

Human Meconium Has Potent Antioxidative Properties  

Microsoft Academic Search

In vitro the antioxidative capacity of pooled and lyophilized human meconium, measured by chemiluminescence, was compared to that of three potent antioxidants: vitamin C, a vitamin E analogue and a synthetic antioxidant, butylated hydroxytoluene. Meconium showed a significant superoxide trapping and peroxidation prevention capacity, but its capacity to trap peroxyl radicals was minor. These effects of meconium were possibly due

Pekka Kääpä; Jaakko Kytölä; Hanna Soukka; Markku Ahotupa

1997-01-01

120

Phenyltriazolinones as potent factor Xa inhibitors.  

PubMed

We have discovered that phenyltriazolinone is a novel and potent P1 moiety for coagulation factor Xa. X-ray structures of the inhibitors with a phenyltriazolinone in the P1 position revealed that the side chain of Asp189 has reoriented resulting in a novel S1 binding pocket which is larger in size to accommodate the phenyltriazolinone P1 substrate. PMID:20100660

Quan, Mimi L; Pinto, Donald J P; Rossi, Karen A; Sheriff, Steven; Alexander, Richard S; Amparo, Eugene; Kish, Kevin; Knabb, Robert M; Luettgen, Joseph M; Morin, Paul; Smallwood, Angela; Woerner, Francis J; Wexler, Ruth R

2010-01-11

121

Peptide Fragments of a ?-Defensin Derivative with Potent Bactericidal Activity ?  

PubMed Central

?-Defensins are known to be both antimicrobial and able to chemoattract various immune cells. Although the sequences of paralogous genes are not highly conserved, the core defensin structure is retained. Defb14-1CV has bactericidal activity similar to that of its parent peptide (murine ?-defensin Defb14) despite all but one of the canonical six cysteines being replaced with alanines. The 23-amino-acid N-terminal half of Defb14-1CV is a potent antimicrobial while the C-terminal half is not. Here, we use a library of peptide derivatives to demonstrate that the antimicrobial activity can be localized to a particular region. Overlapping fragments of the N-terminal region were tested for their ability to kill Gram-positive and Gram-negative bacteria. We demonstrate that the most N-terminal fragments (amino acids 1 to 10 and 6 to 17) are potent antimicrobials against Gram-negative bacteria whereas fragments based on sequence more C terminal than amino acid 13 have very poor activity against both Gram-positive and -negative types. We further test a series of N-terminal deletion peptides in both their monomeric and dimeric forms. We find that bactericidal activity is lost against both Gram types as the deletion region increases, with the point at which this occurs varying between bacterial strains. The dimeric form of the peptides is more resistant to the peptide deletions, but this is not due just to increased charge. Our results indicate that the primary sequence, together with structure, is essential in the bactericidal action of this ?-defensin derivative peptide and importantly identifies a short fragment from the peptide that is a potent bactericide.

Reynolds, Natalie L.; De Cecco, Martin; Taylor, Karen; Stanton, Chloe; Kilanowski, Fiona; Kalapothakis, Jason; Seo, Emily; Uhrin, Dusan; Campopiano, Dominic; Govan, John; Macmillan, Derek; Barran, Perdita; Dorin, Julia R.

2010-01-01

122

Solvation induced morphological effects on the polymer/metal contacts  

NASA Astrophysics Data System (ADS)

Polymer/metal interfaces play an important role in determining the performance of polymer based electronic devices. For most polymer diodes, one of the polymer/metal contacts is usually formed by spin casting a polymer solution onto a metal electrode; we call it polymer-on-metal (POM) contact. The other polymer/metal contact is usually formed by vacuum deposition of metal vapor onto the polymer surface; we call it metal-on-polymer (MOP) contact. In this article, we present evidence that the formation of the POM contact is strongly influenced by the processing of polymer thin films. The POM contact has a greater energy barrier for carrier injection than the MOP contact. The morphology of the polymer thin films, i.e., the relative arrangements of the side groups and conjugated backbone, significantly affects the interfacial characteristics. We also present a simple method of evaluating the morphological effects at the contact.

Liu, Jie; Guo, Tzung-Fang; Shi, Yijian; Yang, Yang

2001-04-01

123

Conformational Changes in BAK, a Pore-forming Proapoptotic Bcl-2 Family Member, upon Membrane Insertion and Direct Evidence for the Existence of BH3-BH3 Contact Interface in BAK Homo-oligomers*  

PubMed Central

During apoptosis, the pro-apoptotic Bcl-2 family proteins BAK and BAX form large oligomeric pores in the mitochondrial outer membrane. Apoptotic factors, including cytochrome c, are released through these pores from the mitochondrial intermembrane space into the cytoplasm where they initiate the cascade of events leading to cell death. To better understand this pivotal step toward apoptosis, a method was developed to induce membrane permeabilization by BAK in the membrane without using the full-length protein. Using a soluble form of BAK with a hexahistidine tag at the C terminus and a liposomal system containing the Ni2+-nitrilotriacetic acid lipid analog that can bind hexahistidine-tagged proteins, BAK oligomers were formed in the presence of the activator protein p7/p15Bid. In this system, we determined the conformational changes in BAK upon membrane insertion by applying the site-directed spin labeling method of EPR to 13 different amino acid locations. Upon membrane insertion, the BH3 domains were reorganized, and the ?5-?6 helical hairpin structure was partially exposed to the membrane environment. The monomer-monomer interface in the oligomeric structure was also mapped by measuring the distance-dependent spin-spin interactions for each residue location. Spin labels attached in the BH3 domain were juxtaposed within 5–10 ? distance in the oligomeric form in the membrane. These results are consistent with the current hypothesis that BAK or BAX forms homodimers, and these homodimers assemble into a higher order oligomeric pore. Detailed analyses of the data provide new insights into the structure of the BAX or BAK homodimer.

Oh, Kyoung Joon; Singh, Pawan; Lee, Kyungro; Foss, Kelly; Lee, Shinyoub; Park, Minji; Lee, Steffi; Aluvila, Sreevidya; Park, Matthew; Singh, Puja; Kim, Ryung-Suk; Symersky, Jindrich; Walters, D. Eric

2010-01-01

124

Carbon-Nanotube-Based Electrical Brush Contacts  

Microsoft Academic Search

Sliding electrical contacts are ubiquitous in electric motors and various forms of monolithic metal - carbon composite brushes and filamentous precious metal brushes represent the highest performance materials available. There is a tremendous opportunity to develop a whole new class of high-performance brush contacts using aligned films of carbon nanotubes, possessing super-compressibility,(1) high electrical and thermal conductivity,(2-3) mechanical strength,(4) tunable

Geza Toth; Jani Mäklin; Niina Halonen; Jaakko Palosaari; Jari Juuti; Heli Jantunen; Krisztian Kordas; W. Gregory Sawyer; Robert Vajtai; Pulickel M. Ajayan

2009-01-01

125

Amorphous Ge bipolar blocking contacts on Ge detectors  

Microsoft Academic Search

The authors report on the performance of high-purity Ge radiation detectors with amorphous Ge (a-Ge) contacts fabricated using RF sputtering techniques. Electrical contacts formed using sputtered a-Ge films on high-purity Ge crystals, both n- and p-type, were found to exhibit good blocking behavior with low leakage currents, with the contact biased under either voltage polarity. The a-Ge contacts have thin

P. N. Luke; C. P. Cork; N. W. Madden; C. S. Rossington; M. F. Wesela

1992-01-01

126

Trust v Law: Promoting and Safeguarding Post?Adoption Contact  

Microsoft Academic Search

For adopted children, arrangements are increasingly made for some form of continuing contact between adoptive and birth families. Supporters of such post?adoption contact argue that it is so important for children's long?term well?being that legislation and judicial intervention should act to promote and enforce contact arrangements. Although legislation (Adoption and Children Act 2002) directs courts to consider contact before making

Carole Smith

2005-01-01

127

Contact resistivity reduction through interfacial layer doping in metal-interfacial layer-semiconductor contacts  

NASA Astrophysics Data System (ADS)

Metal-induced-gap-states model for Fermi-level pinning in metal-semiconductor contacts has been extended to metal-interfacial layer (IL)-semiconductor (MIS) contacts using a physics-based approach. Contact resistivity simulations evaluating various ILs on n-Ge indicate the possibility of forming low resistance contacts using TiO2, ZnO, and Sn-doped In2O3 (ITO) layers. Doping of the IL is proposed as an additional knob for lowering MIS contact resistance. This is demonstrated through simulations and experimentally verified with circular-transfer length method and diode measurements on Ti/n+-ZnO/n-Ge and Ti/ITO/n-Ge MIS contacts.

Gupta, Shashank; Paramahans Manik, Prashanth; Kesh Mishra, Ravi; Nainani, Aneesh; Abraham, Mathew C.; Lodha, Saurabh

2013-06-01

128

Ohmic Contacts on Semiconductors  

NSDL National Science Digital Library

This video from the Indian Institute of Technology, hosted by YouTube, contains a lecture which demonstrates ohmic contacts on semiconductors. The lecture includes slides with equations illustrating related concepts. Running time: 57:48.

2010-06-23

129

Contacts & Information Sources  

Cancer.gov

PLCO Background Information about PLCO Sponsoring Organization Participants/Eligibility PLCO Extended Follow-Up Etiology and Early Marker Studies Cancer Data Access System PLCO Publications Contacts & Information Sources PLCO participants who

130

Contacting My Donor Family  

MedlinePLUS

... My Donor Family Newsroom Minorities Contacting My Donor Family Writing anything can be a challenge. Staring at ... down to write a note to your donor family can feeling overwhelming. The good news is that ...

131

Improved EKG Contact.  

National Technical Information Service (NTIS)

The patent application is directed to providing an apparatus located on the body of a living animal for sensing internal electrical potentials. An electrical contact has a resilient outwardly reaching member coupled to remote circuitry for performing an e...

A. F. Langguth

1975-01-01

132

Types of Contact Lenses  

MedlinePLUS

... objects. This procedure is primarily used for the correction of myopia (nearsightedness). Overnight Ortho-K lenses are ... contact lenses. Others will find that their vision correction will wear off during the day. The vision ...

133

ELECTRIC CONTACT MEANS  

DOEpatents

A switch adapted to maintain electrical connections under conditions of vibration or acceleration is described. According to the invention, thc switch includes a rotatable arm carrying a conductive bar arranged to close against two contacts spaced in the same plane. The firm and continuous engagement of the conductive bar with the contacts is acheived by utilizeing a spring located betwenn the vbar and athe a rem frzme and slidable mounting the bar in channel between two arms suspendef from the arm frame.

Grear, J.W. Jr.

1959-03-10

134

Disposable contact lenses.  

PubMed

Disposable soft contact lenses are an alternative to conventional extended-wear lenses and provide an acceptable margin of safety and convenience for the wearer. The lenses are worn for one to two weeks and then discarded. Buildup of tear film deposits is minimized, and the need for cleaning and disinfecting solutions is eliminated. The long-term safety of disposable contact lenses is unknown. PMID:2021100

White, G L; Thiese, S M; Olafsson, H E; Lundergan, M K

1991-05-01

135

The platelet contacts during aggregation  

Microsoft Academic Search

APD-stimulated and aggregated platelets show dense structures (DS) on their free surfaces and filament bridges within 40–50 nm wide spaces of contacts between aggregating platelets (bridge contacts). Within the bridge contacts tight contacts are observed. Adjacent to tight contacts plasmalemmal openings into a canalicular system are seen. Pits and the central ends of these membranes are coated as seen in

Eberhard Morgenstern; Hans-Joachim Reimers

1984-01-01

136

Potent tyrosinase inhibitors from Trifolium balansae.  

PubMed

Trifolium balansae (Leguminosae) yielded a phytylester, phytyl-1-hexanoate, three steroids, stigmast-5-ene-3 beta,26-diol, stigmast-5-ene-3-ol and campesterol, and an alcohol, pentacosanol which were reported for the first time from T.balansae. The structures of the isolates were determined by 1D and 2D NMR techniques and MS spectroscopy. Compounds 1-5 were tested for their enzyme tyrosinase activity. While compounds 1 and 5 did not show any inhibition against the enzyme tyrosinase, compounds 2, 3, and 4 exhibited potent inhibition against tyrosinase. Highly potent (IC50 = 2.39 microM) inhibition was found by compound 2, when compared with the standard tyrosinase inhibitors Kojic acid and L-mimosine. PMID:16901809

Sabudak, Temine; Tareq Hassan Khan, Mahmut; Iqbal Choudhary, M; Oksuz, Sevil

2006-06-01

137

Dmt and opioid peptides: a potent alliance.  

PubMed

The introduction of the Dmt (2',6'-dimethyl-L-tyrosine)-Tic pharmacophore into the design of opioid ligands produced an extraordinary family of potent delta-opioid receptor antagonists and heralded a new phase in opioid research. First reviewed extensively in 1998, the incorporation of Dmt into a diverse group of opioid molecules stimulated the opioid field leading to the development of unique analogues with remarkable properties. This overview will document the crucial role played by this residue in the proliferation of opioid peptides with high receptor affinity (K(i) equal to or less than 1 nM) and potent bioactivity. The discussion will include the metamorphosis between delta-opioid receptor antagonists to delta-agonists based solely on subtle structural changes at the C-terminal region of the Dmt-Tic pharmacophore as well as their behavior in vivo. Dmt may be considered promiscuous due to the acquisition of potent mu-agonism by dermorphin and endomorphin derivatives as well as by a unique class of opioidmimetics containing two Dmt residues separated by alkyl or pyrazinone linkers. Structural studies on the Dmt-Tic compounds were enhanced tremendously by x-ray diffraction data for three potent and biologically diverse Dmt-Tic opioidmimetics that led to the development of pharmacophores for both delta-opioid receptor agonists and antagonists. Molecular modeling studies of other unique Dmt opioid analogues illuminated structural differences between delta- and mu-receptor ligand interactions. The future of these compounds as therapeutic applications for various medical syndromes including the control of cancer-associated pain is only a matter of time and perseverance. PMID:12767112

Bryant, Sharon D; Jinsmaa, Yunden; Salvadori, Severo; Okada, Yoshio; Lazarus, Lawrence H

2003-01-01

138

Tetrahydrogestrinone Is a Potent Androgen and Progestin  

Microsoft Academic Search

Tetrahydrogestrinone (THG) was recently identified as a novel steroid used illicitly to improve athletic performance. Althoughitsstructureiscloselyrelatedtogestrinone,a19-nor progestin, and resembles that of trenbolone, THG was never marketed, so information on its hormonal properties is not known. In this study, we demonstrate that THG is a highly potent androgen and progestin in a yeast-based in vitro bio- assay system expressing human androgen

ALISON K. DEATH; KRISTINE C. Y. MCGRATH; RYMANTAS KAZLAUSKAS; DAVID J. HANDELSMAN

2010-01-01

139

The contact caveat: negative contact predicts increased prejudice more than positive contact predicts reduced prejudice.  

PubMed

Contact researchers have largely overlooked the potential for negative intergroup contact to increase prejudice. In Study 1, we tested the interaction between contact quantity and valence on prejudice toward Black Australians (n = 1,476), Muslim Australians (n = 173), and asylum seekers (n = 293). In all cases, the association between contact quantity and prejudice was moderated by its valence, with negative contact emerging as a stronger and more consistent predictor than positive contact. In Study 2, White Americans (n = 441) indicated how much positive and negative contact they had with Black Americans on separate measures. Although both quantity of positive and negative contact predicted racism and avoidance, negative contact was the stronger predictor. Furthermore, negative (but not positive) contact independently predicted suspicion about Barack Obama's birthplace. These results extend the contact hypothesis by issuing an important caveat: Negative contact may be more strongly associated with increased racism and discrimination than positive contact is with its reduction. PMID:22941796

Barlow, Fiona Kate; Paolini, Stefania; Pedersen, Anne; Hornsey, Matthew J; Radke, Helena R M; Harwood, Jake; Rubin, Mark; Sibley, Chris G

2012-08-31

140

Fabrication of High-Quality Co2FeSi/SiO x N y /Si(100) Tunnel Contacts Using Radical-Oxynitridation-Formed SiO x N y Barrier for Si-Based Spin Transistors  

NASA Astrophysics Data System (ADS)

A high-quality Co2FeSi (CFS)/SiO x N y /Si tunnel junction was fabricated, in which the SiO x N y barrier layer was formed by radical oxynitridation of an Si(100) substrate and the CFS electrode was formed by silicidation of an Fe/Co/amorphous-Si multilayer deposited on the barrier layer. The ultrathin SiO x N y barrier layer completely blocked diffusion of Co and Fe atoms into the Si substrate during rapid thermal annealing (RTA) for the silicidation. X-ray diffraction investigations clarified that the CFS film on the ultrathin SiO x N y barrier layer exhibited a highly (110)-oriented texture structure and that the film had the L21 structure with a high degree of L21 order. High resolution cross-sectional transmission electron microscopy investigations revealed that the CFS/SiO x N y interface was atomically flat and that the crystal lattice of the CFS film was directly grown on the SiO x N y surface without degradation of the crystallinity at the interface.

Takamura, Yota; Hayashi, Kengo; Shuto, Yusuke; Sugahara, Satoshi

2012-05-01

141

Diagnosis and management of contact dermatitis.  

PubMed

Contact dermatitis is a common inflammatory skin condition characterized by erythematous and pruritic skin lesions that occur after contact with a foreign substance. There are two forms of contact dermatitis: irritant and allergic. Irritant contact dermatitis is caused by the non-immune-modulated irritation of the skin by a substance, leading to skin changes. Allergic contact dermatitis is a delayed hypersensitivity reaction in which a foreign substance comes into contact with the skin; skin changes occur after reexposure to the substance. The most common substances that cause contact dermatitis include poison ivy, nickel, and fragrances. Contact dermatitis usually leads to erythema and scaling with visible borders. Itching and discomfort may also occur. Acute cases may involve a dramatic flare with erythema, vesicles, and bullae; chronic cases may involve lichen with cracks and fissures. When a possible causative substance is known, the first step in confirming the diagnosis is determining whether the problem resolves with avoidance of the substance. Localized acute allergic contact dermatitis lesions are successfully treated with mid- or high-potency topical steroids, such as triamcinolone 0.1% or clobetasol 0.05%. If allergic contact dermatitis involves an extensive area of skin (greater than 20 percent), systemic steroid therapy is often required and offers relief within 12 to 24 hours. In patients with severe rhus dermatitis, oral prednisone should be tapered over two to three weeks because rapid discontinuation of steroids can cause rebound dermatitis. If treatment fails and the diagnosis or specific allergen remains unknown, patch testing should be performed. PMID:20672788

Usatine, Richard P; Riojas, Marcela

2010-08-01

142

Metal-Semiconductor Contacts  

NASA Astrophysics Data System (ADS)

Metal-semiconductor contacts display a range of electrical characteristics from strongly rectifying to ohmic, each having its own applications. The rectifying properties of metal points on metallic sulphides were used extensively as detectors in early radio experiments, while during the second world war the rectifying point contact diode became important as a frequency detector and low level microwave radar detector [1]. Since 1945 the development of metal semiconductor contacts has been stimulated by the intense activity in the field of semiconductor physics and has remained vital in the ohmic connection of semiconductor devices with the outside world. The developments in surface science and the increased use of Schottky barriers in microelectronics has lead to much research with the aim of obtaining a full understanding of the physics of barrier formation and of current transport across the metal-semiconductor interface. Large gain spin electronic devices are possible with appropriate designs by incorporating ferromagnetic layers with semiconductors such as silicon [2]. This inevitably leads to metal-semiconductor contacts, and the impact of such junctions on the device must be considered. In this section we aim to look simply at the physical models that can be used to understand the electrical properties that can arise from these contacts, and then briefly discuss how deviations of these models can occur in practical junctions.

Pugh, D. I.

143

Contact Dermatitis - Epidemiological Study  

PubMed Central

ABSTRACT Aim: To evaluate the real incidence of contact dermatitis, to identify the most common allergens, the favoring factors, to establish the prophylaxis methods, the key for a correct management of the patient with contact dermatitis. Method: A retrospective study, on the patients that refers to the Dermatology Clinic, "St. Spiridon" Emergency Hospital Iasi, between 01.01.2006 and 31.12. 2009, based on demographic items, the type of contact dermatitis and the allergens implicated. Results: we enrolled 353 patients between 2006-2009, representing 3,89% from the hospitalized patients; the study reveals a higher incidence at women (60,27%), similar with data from literature; the majority of the patients was aged over 45, with the higher rate in the interval of 45-65 years old; the most frequent implicated allergens and irritants were plants (26,31% - 92 patients) and topical drugs and antiseptics (25,65% - 89 patients); the area most affected was the face (25%) and the hands (19,07%), from which almost 80-90% was occupational dermatitis. The distribution of cases depending on the type of contact dermatitis indicates an approximate percentage of those allergic to those irritant. Conclusions: The real prevalence of this disease is unknown, being frequently a missed diagnosis (other kinds of eczema), the key of the correct diagnose being a repeated, exhaustive anamnesis, revealing all the favoring conditions and possible contact allergens.

STATESCU, Laura; BRANISTEANU, Daciana; DOBRE, C.; SOLOVASTRU, Laura Gheuca; VASILCA, A.; PETRESCU, Zenaida; AZOICAI, Doina

2011-01-01

144

Intergroup contact theory.  

PubMed

Allport specified four conditions for optimal intergroup contact: equal group status within the situation, common goals, intergroup cooperation and authority support. Varied research supports the hypothesis, but four problems remain. 1. A selection bias limits cross-sectional studies, since prejudiced people avoid intergroup contact. Yet research finds that the positive effects of cross-group friendship are larger than those of the bias. 2. Writers overburden the hypothesis with facilitating, but not essential, conditions. 3. The hypothesis fails to address process. The chapter proposes four processes: learning about the outgroup, changed behavior, affective ties, and ingroup reappraisal. 4. The hypothesis does not specify how the effects generalize to other situations, the outgroup or uninvolved outgroups. Acting sequentially, three strategies enhance generalization-decategorization, salient categorization, and recategorization. Finally, both individual differences and societal norms shape intergroup contact effects. The chapter outlines a longitudinal intergroup contact theory. It distinguishes between essential and facilitating factors, and emphasizes different outcomes for different stages of contact. PMID:15012467

Pettigrew, T F

1998-01-01

145

Glenohumeral contact forces.  

PubMed

Glenohumeral contact forces have only been calculated previously either for simple abduction or for athletic activities. The objective of this study was to determine the glenohumeral contact forces for tasks which are demanding of the shoulder but which would commonly be performed by older people. The functional tasks chosen were using the arms to stand up from and sit down into a chair, walking with a cane, lifting a 5 kg box to shoulder height with both hands, and lifting a 10 kg suitcase. The trunk angles, arm angles and hand loads of six healthy subjects, average age 55 years, were recorded. This information was input into a biomechanical computer model which optimized the muscle force distribution by minimizing the sum of squared muscle stresses subject to constraints on the maximum muscle forces and maintaining the direction of the resultant force within the glenoid fossa. Average contact forces ranged from 1.3 to 2.4 times body weight (930-1720 N), the highest force being for lifting a suitcase. This latter value would be even higher if lifting either a greater load or to a greater height. Thus, contact forces at the shoulder should not be underestimated. This study provides functionally relevant contact forces which can be used for mechanical testing or finite element modelling of shoulder prostheses. PMID:11201411

Anglin, C; Wyss, U P; Pichora, D R

2000-01-01

146

Contact Interface Verification for DYNA3D Scenario 1: Basic Contact  

SciTech Connect

A suite of test problems has been developed to examine contact behavior within the nonlinear, three-dimensional, explicit finite element analysis (FEA) code DYNA3D (Lin, 2005). The test problems address the basic functionality of the contact algorithms, including the behavior of various kinematic, penalty, and Lagrangian enforcement formulations. The results from the DYNA3D analyses are compared to closed form solutions to verify the contact behavior. This work was performed as part of the Verification and Validation efforts of LLNL W Program within the NNSA's Advanced Simulation and Computing (ASC) Program. DYNA3D models the transient dynamic response of solids and structures including the interactions between disjoint bodies (parts). A wide variety of contact surfaces are available to represent the diverse interactions possible during an analysis, including relative motion (sliding), separation and gap closure (voids), and fixed relative position (tied). The problem geometry may be defined using a combination of element formulations, including one-dimensional beam and truss elements, two-dimensional shell elements, and three-dimensional solid elements. Consequently, it is necessary to consider various element interactions for each contact algorithm being verified. Most of the contact algorithms currently available in DYNA3D are examined; the exceptions are the Type 4--Single Surface Contact and Type 11--SAND algorithms. It is likely that these algorithms will be removed since their functionality is embodied in other, more robust, contact algorithms. The automatic contact algorithm is evaluated using the Type 12 interface. Two other variations of automatic contact, Type 13 and Type 14, offer additional means to adapt the interface domain, but share the same search and restoration algorithms as Type 12. The contact algorithms are summarized in Table 1. This report and associated test problems examine the scenario where one contact surface exists between two disjoint bodies. These test problems focus on whether a particular contact algorithm properly represents the interactions along the interface. A companion report (McMichael, 2006) and test problems address the multi-contact scenario in which multiple bodies interact with each other via multiple interfaces. The multi-contact test problems examine whether any ordering issues exist in the contact logic. The test problems are analyzed using version 5.2 (compiled on 12/22/2005) of DYNA3D. The analytical results are used to form baseline solutions for subsequent regression testing.

McMichael, L D

2006-05-10

147

Hidden contacts with penicillin*  

PubMed Central

There is much evidence to indicate that the most common cause of drug allergy in recent years has been penicillin, and sensitive patients are warned to avoid treatment with this antibiotic. There are, however, a number of less obvious ways in which the penicillin-sensitive person may be exposed to the risk of contact with this drug, even minute amounts of which have been shown to cause allergic reactions. Four of the main hidden sources of such contact are discussed in detail in this paper.

Siegel, Bernard B.

1959-01-01

148

Carrageenan Is a Potent Inhibitor of Papillomavirus Infection  

PubMed Central

Certain sexually transmitted human papillomavirus (HPV) types are causally associated with the development of cervical cancer. Our recent development of high-titer HPV pseudoviruses has made it possible to perform high-throughput in vitro screens to identify HPV infection inhibitors. Comparison of a variety of compounds revealed that carrageenan, a type of sulfated polysaccharide extracted from red algae, is an extremely potent infection inhibitor for a broad range of sexually transmitted HPVs. Although carrageenan can inhibit herpes simplex viruses and some strains of HIV in vitro, genital HPVs are about a thousand-fold more susceptible, with 50% inhibitory doses in the low ng/ml range. Carrageenan acts primarily by preventing the binding of HPV virions to cells. This finding is consistent with the fact that carrageenan resembles heparan sulfate, an HPV cell-attachment factor. However, carrageenan is three orders of magnitude more potent than heparin, a form of cell-free heparan sulfate that has been regarded as a highly effective model HPV inhibitor. Carrageenan can also block HPV infection through a second, postattachment heparan sulfate–independent effect. Carrageenan is in widespread commercial use as a thickener in a variety of cosmetic and food products, ranging from sexual lubricants to infant feeding formulas. Some of these products block HPV infectivity in vitro, even when diluted a million-fold. Clinical trials are needed to determine whether carrageenan-based products are effective as topical microbicides against genital HPVs.

Buck, Christopher B; Thompson, Cynthia D; Roberts, Jeffrey N; Muller, Martin; Lowy, Douglas R; Schiller, John T

2006-01-01

149

Potent inhibition of tau fibrillization with a multivalent ligand  

SciTech Connect

Small-molecule inhibitors of tau fibrillization are under investigation as tools for interrogating the tau aggregation pathway and as potential therapeutic agents for Alzheimer's disease. Established inhibitors include thiacarbocyanine dyes, which can inhibit recombinant tau fibrillization in the presence of anionic surfactant aggregation inducers. In an effort to increase inhibitory potency, a cyclic bis-thiacarbocyanine molecule containing two thiacarbocyanine moieties was synthesized and characterized with respect to tau fibrillization inhibitory activity by electron microscopy and ligand aggregation state by absorbance spectroscopy. Results showed that the inhibitory activity of the bis-thiacarbocyanine was qualitatively similar to a monomeric cyanine dye, but was more potent with 50% inhibition achieved at {approx}80 nM concentration. At all concentrations tested in aqueous solution, the bis-thiacarbocyanine collapsed to form a closed clamshell structure. However, the presence of tau protein selectively stabilized the open conformation. These results suggest that the inhibitory activity of bis-thiacarbocyanine results from multivalency, and reveal a route to more potent tau aggregation inhibitors.

Honson, Nicolette S.; Jensen, Jordan R. [Center for Molecular Neurobiology, Department of Molecular and Cellular Biochemistry, College of Medicine, Ohio State University, Columbus, OH 43210 (United States); Darby, Michael V. [College of Pharmacy, Ohio State University, Columbus, OH 43210 (United States); Kuret, Jeff [Center for Molecular Neurobiology, Department of Molecular and Cellular Biochemistry, College of Medicine, Ohio State University, Columbus, OH 43210 (United States)], E-mail: kuret.3@osu.edu

2007-11-09

150

Identification of a Potent Endothelium-Derived Angiogenic Factor  

PubMed Central

The secretion of angiogenic factors by vascular endothelial cells is one of the key mechanisms of angiogenesis. Here we report on the isolation of a new potent angiogenic factor, diuridine tetraphosphate (Up4U) from the secretome of human endothelial cells. The angiogenic effect of the endothelial secretome was partially reduced after incubation with alkaline phosphatase and abolished in the presence of suramin. In one fraction, purified to homogeneity by reversed phase and affinity chromatography, Up4U was identified by MALDI-LIFT-fragment-mass-spectrometry, enzymatic cleavage analysis and retention-time comparison. Beside a strong angiogenic effect on the yolk sac membrane and the developing rat embryo itself, Up4U increased the proliferation rate of endothelial cells and, in the presence of PDGF, of vascular smooth muscle cells. Up4U stimulated the migration rate of endothelial cells via P2Y2-receptors, increased the ability of endothelial cells to form capillary-like tubes and acts as a potent inducer of sprouting angiogenesis originating from gel-embedded EC spheroids. Endothelial cells released Up4U after stimulation with shear stress. Mean total plasma Up4U concentrations of healthy subjects (N?=?6) were sufficient to induce angiogenic and proliferative effects (1.34±0.26 nmol L-1). In conclusion, Up4U is a novel strong human endothelium-derived angiogenic factor.

Jankowski, Vera; Tolle, Markus; Tran, Thi Nguyet Anh; van der Giet, Markus; Schuchardt, Mirjam; Lehmann, Kerstin; Janke, Doreen; Flick, Burkhard; Ortiz, Alberto Arduan; Sanchez, Nino Maria Dolores; Tepel, Martin; Zidek, Walter; Jankowski, Joachim

2013-01-01

151

Transport properties of clean quantum point contacts  

NASA Astrophysics Data System (ADS)

Quantum point contacts are fundamental building blocks for mesoscopic transport experiments and play an important role in recent interference and fractional quantum Hall experiments. However, it is unclear how electron-electron interactions and the random disorder potential influence the confinement potential and give rise to phenomena such as the mysterious 0.7 anomaly. Novel growth techniques of AlXGa1-XAs heterostructures for high-mobility two-dimensional electron gases enable us to investigate quantum point contacts with a strongly suppressed disorder potential. These clean quantum point contacts indeed show transport features that are obscured by disorder in standard samples. From these transport data, we are able to extract those parameters of the confinement potential that describe its shape in the longitudinal and transverse directions. Knowing the shape (and hence the slope) of the confinement potential might be crucial for predicting which interaction-induced states can best form in quantum point contacts.

Rössler, C.; Baer, S.; de Wiljes, E.; Ardelt, P.-L.; Ihn, T.; Ensslin, K.; Reichl, C.; Wegscheider, W.

2011-11-01

152

QSAR Optimization of Benzofuran and Benzothiophene Sulfono Biphenyl as Potent PTPase-1B Inhibitors  

Microsoft Academic Search

Insulin resistance is associated with a defect in protein tyrosine phosphorylation in the insulin signal transduction cascade. Protein tyrosine phosphatase (PTPase) enzyme dephosphorylates the active form of insulin receptor and thus attenuates its tyrosine kinase activity, therefore the need of potent PTPase inhibitor is there with that intention the Quantitative structure-activity relationship QSAR was performed. QSAR has been established on

Darpan Kaushik; Suroor A. Khan; Ozair Alam; Geeta Chawla; Satish G. Kashedikar

2007-01-01

153

Does Contact Area Matter?  

NSDL National Science Digital Library

Using the same method for measuring friction that was used in the previous lesson (Discovering Friction), students design and conduct an experiment to determine if the amount of area over which an object contacts a surface it is moving across affects the amount of friction encountered.

Engineering K-Ph.d. Program

154

[Contact allergies in musicians].  

PubMed

During the last years, the problem of allergic diseases has increased. Allergies are errant immune responses to a normally harmless substance. In musicians the allergic contact dermatitis to exotic woods is a special problem. Exotic rosewood contains new flavonoids, which trigger an allergic reaction after permanent contact with the instrument. High quality woodwind instruments such as baroque flute or clarinets are made in ebony or palisander because of its great sound. Today instruments for non-professional players are also made in these exotic materials and non-professionals may have the risk to develop contact dermatitis, too. Brass-player has the risk of an allergic reaction to the different metals contained in the metal sheets of modern flutes and brass instruments. Specially nickel and brass alloys are used to product flute tubes or brass instruments. Special problem arises in children: patients who are allergic to plants or foods have a high risk to develop contact dermatitis. Parents don't know the materials of low-priced instruments for beginners. Often unknown cheap woods from exotic areas are used. Low-priced brass instruments contain high amount of brass and other cheap metals. Physicians should advice musician-patients or parents about the risks of the different materials and look for the reason of eczema on mouth, face, or hands. PMID:23233303

Gasenzer, E R; Neugebauer, E A M

2012-12-11

155

Have Confidence in Contact  

ERIC Educational Resources Information Center

|In an article in the May-June 2009 "American Psychologist," we discussed a new approach to reducing prejudice and encouraging more positive intergroup relations (Crisp & Turner, 2009). We named the approach imagined intergroup contact and defined it as "the mental simulation of a social interaction with a member or members of an outgroup…

Crisp, Richard J.; Turner, Rhiannon N.

2010-01-01

156

Multigrid contact detection method.  

PubMed

Contact detection is a general problem of many physical simulations. This work presents a O(N) multigrid method for general contact detection problems (MGCD). The multigrid idea is integrated with contact detection problems. Both the time complexity and memory consumption of the MGCD are O(N). Unlike other methods, whose efficiencies are influenced strongly by the object size distribution, the performance of MGCD is insensitive to the object size distribution. We compare the MGCD with the no binary search (NBS) method and the multilevel boxing method in three dimensions for both time complexity and memory consumption. For objects with similar size, the MGCD is as good as the NBS method, both of which outperform the multilevel boxing method regarding memory consumption. For objects with diverse size, the MGCD outperform both the NBS method and the multilevel boxing method. We use the MGCD to solve the contact detection problem for a granular simulation system based on the discrete element method. From this granular simulation, we get the density property of monosize packing and binary packing with size ratio equal to 10. The packing density for monosize particles is 0.636. For binary packing with size ratio equal to 10, when the number of small particles is 300 times as the number of big particles, the maximal packing density 0.824 is achieved. PMID:17500829

He, Kejing; Dong, Shoubin; Zhou, Zhaoyao

2007-03-28

157

Contact: Releasing the news  

NASA Astrophysics Data System (ADS)

The problem of mass behavior after man's future contacts with other intelligences in the universe is not only a challenge for social scientists and political leaders all over the world, but also a cultural time bomb as well. In fact, since the impact of CETI (Contact with Extraterrestrial Intelligence) on human civilization, with its different cultures, might cause a serious socio-anthropological shock, a common and predetermined worldwide strategy is necessary in releasing the news after the contact, in order to keep possible manifestations of fear, panic and hysteria under control. An analysis of past studies in this field and of parallel historical situations as analogs suggests a definite "authority crisis" in the public as a direct consequence of an unexpected release of the news, involving a devastating "chain reaction" process (from both the psychological and sociological viewpoints) of anomie and maybe the collapse of today's society. The only way to prevent all this is to prepare the world's public opinion concerning contact before releasing the news, and to develop a long-term strategy through the combined efforts of scientists, political leaders, intelligence agencies and the mass media, in order to create the cultural conditions in which a confrontation with ETI won't affect mankind in a traumatic way. Definite roles and tasks in this multi-level model are suggested.

Pinotti, Roberto

158

Plasticity in fretting contact  

Microsoft Academic Search

The fretting problem of a cyclically loaded cylinder on a flat elastic–plastic surface is analyzed under the assumption of plane strain. Severe fretting conditions are modeled by applying a constant normal load and a cyclic tangential load to the cylinder and describing the contact behavior using a Coulomb friction law. Detailed numerical results are presented for the evolution of plastic

J. M. Ambrico; M. R. Begley

2000-01-01

159

The contact percolation transition  

NASA Astrophysics Data System (ADS)

Typical quasistatic compression algorithms for generating jammed packings of athermal, purely repulsive particles begin with dilute configurations and then apply successive compressions with relaxation of the elastic energy allowed between each compression step. It is well-known that during isotropic compression athermal systems with purely repulsive interactions undergo a jamming transition at packing fraction ?J from an unjammed state with zero pressure to a jammed, rigid state with nonzero pressure. Using extensive computer simulations, we show that a novel second-order-like, contact percolation, which signals the formation of a system-spanning cluster of mutually contacting particles, occurs at ?P< ?J, preceding the jamming transition. By measuring the number of non-floppy modes of the dynamical matrix, the displacement field between successive compression steps, and the overlap between the adjacency matrix, which represents the network of contacting grains, at ? and ?J, we find that the contact percolation transition also heralds the onset of nontrivial response to applied stress. Highly heterogeneous, cooperative, and non-affine particle motion occurs in unjammed systems significantly below the jamming transition for ?P< ?< ?J,

Shen, Tianqi; O'Hern, Corey; Shattuck, Mark

2012-02-01

160

Contact hypothesis in ethnic relations  

Microsoft Academic Search

Reviews research regarding the effects of intergroup contact on ethnic relations. The investigations discussed include both intra- and cross-cultural studies involving contact between various ethnic groups. The principles and generalizations emerging from these studies are categorized under (1) opportunities for contact, (2) the principle of equal status, (3) contact with high-status representatives of a minority group, (4) cooperative and competitive

Yehuda Amir

1969-01-01

161

Thioester derivatives of the natural product psammaplin A as potent histone deacetylase inhibitors.  

PubMed

There has been significant interest in the bioactivity of the natural product psammaplin A, most recently as a potent and isoform selective HDAC inhibitor. Here we report our preliminary studies on thioester HDAC inhibitors derived from the active monomeric (thiol) form of psammaplin A, as a means to improve compound delivery into cells. We have discovered that such compounds exhibit both potent cytotoxicity and enzymatic inhibitory activity against recombinant HDAC1. The latter effect is surprising since previous SAR suggested that modification of the thiol functionality should detrimentally affect HDAC potency. We therefore also report our preliminary studies on the mechanism of action of this observed effect. PMID:23400330

Baud, Matthias G J; Leiser, Thomas; Petrucci, Vanessa; Gunaratnam, Mekala; Neidle, Stephen; Meyer-Almes, Franz-Josef; Fuchter, Matthew J

2013-01-15

162

CCR - Invalid Form Data  

Cancer.gov

CCR Home | About CCR | CCR Intranet Form Validation Error The data that you are trying to submit to the server is invalid. If you believe that the data you have submitted is valid, please contact the webmaster by clicking here or by sending an e-mail

163

Contacting the Government among College Students  

ERIC Educational Resources Information Center

|The literature on political participation indicates that initiating contacts with the government is a vital form of civic engagement. Using this criterion to define participation, some researchers claim that students in general are apathetic about government and have poor efficacy about public affairs. The present study examines this assumption…

Yaghi, Abdulfattah

2009-01-01

164

Ophthalmic glucose monitoring using disposable contact lenses  

Microsoft Academic Search

Summary form only given. We have developed a range of disposable and colorless tear glucose sensing contact lenses, using off-the-shelf lenses embedded with new water soluble, highly fluorescent and glucose sensitive boronic acid containing fluorophores. The new lenses are readily able to track tear glucose levels and therefore blood glucose levels, which are ideally suited for potential use by diabetics.

C. Geddes

2004-01-01

165

CTEP — Forms, Templates and Documents  

Cancer.gov

Skip to Content Home | Investigator Resources | Protocol Development | Initiatives/Programs/Collaborations | Links to More Resources | Funding Opportunities | About CTEP Home | Sitemap | Contact CTEP Search this site Forms, Templates and Documents CTEP

166

[Contact allergy to cosmetics].  

PubMed

This article gives the results of contact allergic reactions to cosmetics seen between 1985 and 1990 (462 patients investigated) and between 1991 and 1996 (486 patients investigated). Perfume components remain the most frequently occurring allergens in cosmetics. They are followed by preservative agents, a class within which important shifts have occurred over time (e.g. as with the isothiazolinone mixture). Excipients and certainly emulsifiers (e.g. cocamidopropylbetaine) are potentially not only irritants but also allergens. Among the "active" or category-specific ingredients, oxidative hair dyes, based on paraphenylenediamine and derivatives, and nail care products, based on (meth)acrylates are particularly apt to cause professional dermatoses. Finally, the share of sunscreens as cosmetic allergens remains limited, which may well be because a contact or photocontactallergy is often not recognized since the differential diagnosis with a primary sun intolerance is not always obvious. PMID:9479432

Goossens, A; Merckx, L

1997-12-01

167

Occupational Contact Dermatitis: Hairdressers  

Microsoft Academic Search

\\u000a Occupational contact dermatitis occurs in about half of all hairdressers and makes hairdressers susceptible to most skin diseases.\\u000a The clinical manifestations are typically seen as hand eczema. The hand eczema starts often at the time of hairdressing apprenticeship,\\u000a and protective gloves are very important for preventing eczema in this occupation. Persulfates are (almost) always used in\\u000a bleaching procedures in hairdressing

Heidi Søsted

168

Obituary--rigid contact lenses.  

PubMed

Scleral and corneal rigid lenses represented 100 per cent of the contact lens market immediately prior to the invention of soft lenses in the mid-1960s. In the United Kingdom today, rigid lenses comprise 2 per cent of all new lens fits. Low rates of rigid lens fitting are also apparent in 27 other countries which have recently been surveyed. Thus, the 1998 prediction of the author that rigid lenses--also referred to as 'rigid gas permeable' (RGP) lenses or 'gas permeable' (GP) lenses--would be obsolete by the year 2010 has essentially turned out to be correct. In this obituary, the author offers 10 reasons for the demise of rigid lens fitting: initial rigid lens discomfort; intractable rigid lens-induced corneal and lid pathology; extensive soft lens advertising; superior soft lens fitting logistics; lack of rigid lens training opportunities; redundancy of the rigid lens 'problem solver' function; improved soft toric and bifocal/varifocal lenses; limited uptake of orthokeratology; lack of investment in rigid lenses; and the emergence of aberration control soft lenses. Rigid lenses are now being fitted by a minority of practitioners with specialist skills/training. Certainly, rigid lenses can no longer be considered as a mainstream form of contact lens correction. May their dear souls (bulk properties) rest in peace. PMID:20674469

Efron, Nathan

2010-07-31

169

Functional modular contact lens  

NASA Astrophysics Data System (ADS)

Tear fluid offers a potential route for non-invasive sensing of physiological parameters. Utilization of this potential depends on the ability to manufacture sensors that can be placed on the surface of the eye. A contact lens makes a natural platform for such sensors, but contact lens polymers present a challenge for sensor fabrication. This paper describes a microfabrication process for constructing sensors that can be integrated into the structure of a functional contact lens in the future. To demonstrate the capabilities of the process, an amperometric glucose sensor was fabricated on a polymer substrate. The sensor consists of platinum working and counter electrodes, as well as a region of indium-tin oxide (ITO) for glucose oxidase immobilization. An external silver-silver chloride electrode was used as the reference electrode during the characterization experiments. Sensor operation was validated by hydrogen peroxide measurements in the 10- 20 ?M range and glucose measurements in the 0.125-20 mM range.

Shum, Angela J.; Cowan, Melissa; Lähdesmäki, Ilkka; Lingley, Andrew; Otis, Brian; Parviz, Babak A.

2009-08-01

170

Electrical contacts for a thin-film semiconductor device  

DOEpatents

A method of fabricating spaced-apart back contacts on a thin film of semiconductor material by forming strips of buffer material on top of the semiconductor material in locations corresponding to the desired dividing lines between back contacts, forming a film of metal substantially covering the semiconductor material and buffer strips, and scribing portions of the metal film overlying the buffer strips with a laser without contacting the underlying semiconductor material to separate the metal layer into a plurality of back contacts. The buffer material serves to protect the underlying semiconductor material from being damaged during the laser scribing. Back contacts and multi-cell photovoltaic modules incorporating such back contacts also are disclosed.

Carlson, David E. (Yardley, PA); Dickson, Charles R. (Pennington, NJ); D' Aiello, Robert V. (East Brunswick, NJ)

1989-08-08

171

Orally Bioavailable Potent Soluble Epoxide Hydrolase Inhibitors  

PubMed Central

A series of N,N?-disubstituted ureas having a conformationally restricted cis- or trans-1,4-cyclohexane ? to the urea were prepared and tested as soluble epoxide hydrolase (sEH) inhibitors. This series of compounds showed low nanomolar to picomolar activities against recombinant human sEH. Both isomers showed similar potencies, but the trans isomers were more metabolically stable in human hepatic microsomes. Furthermore, these new potent inhibitors show a greater metabolic stability in vivo than previously described sEH inhibitors. We demonstrated that trans-4-[4-(3-adamantan-1-ylureido)cyclohexyloxy]benzoic acid 13g (t-AUCB, IC50 = 1.3 ± 0.05 nM) had excellent oral bioavailability (98%, n = 2) and blood area under the curve in dogs and was effective in vivo to treat hypotension in lipopolysaccharide challenged murine models.

Hwang, Sung Hee; Tsai, Hsing-Ju; Liu, Jun-Yan; Morisseau, Christophe; Hammock, Bruce D.

2008-01-01

172

Flavonoid dimers as novel, potent antileishmanial agents.  

PubMed

The present study found that synthetic flavonoid dimers with either polyethylene glycol linker or amino ethyleneglycol linker have marked leishmanicidal activity. Compound 39 showed very consistent and promising leishmanicidal activity for both extracellular promastigotes (IC?? ranging from 0.13 to 0.21 ?M) and intracellular amastigotes (IC?? = 0.63 ?M) irrespective of the drug-sensitivity of parasites. Moreover, compound 39 displayed no toxicity toward macrophage RAW 264.7 cells (IC?? > 100 ?M) and primary mouse peritoneal elicited macrophages (IC?? > 88 ?M). Its high value of therapeutic index (>140) was better than other highly potent antileishmanials such as amphotericin B (therapeutic index = 119). Compound 39 is therefore a new, safe, and effective antileishmanial candidate compound which is even effective against drug-refractory parasites. PMID:22989363

Wong, Iris L K; Chan, Kin-Fai; Chan, Tak Hang; Chow, Larry M C

2012-10-03

173

Metabolism of a potent neuroprotective hydrazide.  

PubMed

Using a drug discovery scheme for Alzheimer's disease (AD) that is based upon multiple pathologies of old age, we identified a potent compound with efficacy in rodent memory and AD animal models. Since this compound, J147, is a phenyl hydrazide, there was concern that it can be metabolized to aromatic amines/hydrazines that are potentially carcinogenic. To explore this possibility, we examined the metabolites of J147 in human and mouse microsomes and mouse plasma. It is shown that J147 is not metabolized to aromatic amines or hydrazines, that the scaffold is exceptionally stable, and that the oxidative metabolites are also neuroprotective. It is concluded that the major metabolites of J147 may contribute to its biological activity in animals. PMID:23582448

Chiruta, Chandramouli; Zhao, Yanrong; Tang, Fangling; Wang, Tao; Schubert, David

2013-03-24

174

Contact mechanics of rough surfaces in tribology: multiple asperity contact  

Microsoft Academic Search

Contact modeling of two rough surfaces under normal approach and with relative motion is carried out to predict real area\\u000a of contact and surface and subsurface stresses affecting friction and wear of an interface. When two macroscopically flat\\u000a bodies with microroughness come in contact, the contact occurs at multiple asperities of arbitrary shapes, and varying sizes\\u000a and heights. Deformation at

Bharat Bhushan

1998-01-01

175

Piezoresistive cantilevers for characterizing thin-film gold electrical contacts  

NASA Astrophysics Data System (ADS)

The electronics packaging and testing industry is interested in new methods for making contacts to electronic chips to allow improvement or replacement of existing interconnect technologies. One approach involves the use of flexible contact structures integrated with the package or the testing apparatus which allow the device to be fully contacted by placing and pressing the interconnect array into contact. This technoOlogy depends on the properties of low-force electrical contacts. The research presented is a careful characterization of the electromechanical properties of such contacts, using instrumented MEMS force sensors. This work provides a sensor, measurement system and methodology for low force contact resistance data collection. This research includes the design, fabrication, and characterization of a micromechanical force sensor integrated with a 4-wire electrical contact characterization capability, a set of parametric measurements in the 10nN-10mN regime, and the development of qualitative design rules for small force thin film gold electrical contacts. The sensor consists of a silicon cantilever beam with a piezoresistive force sensor suitable for high-accuracy force measurements in the mN-nN range. The contact tips consist of a glass spheres for a controlled contact geometry as well as polystyrene spheres for highly-compliant contact structures. The contact halves are coated with varying thicknesses of evaporated, sputtered, or plated thin film gold. Combined with AFM scans and nanoindentation hardness measurements, correlations are found between the contact behavior, resistance measurements, and material characteristics over varied contact sizes, film types, thicknesses, and substrates. Mean stable contact resistance (<10) is achieved with less than 100muN force for 1800A to 1.2mum thick gold. Differences in contact resistance from Hertzian elastic contact theory are attributed to the presence of asperities on the contact spheres, plasticity in the films, and differences in material properties for thin film vs. bulk form. The two most significant factors affecting contact resistance are film hardness and surface roughness. The contact resistance decreases and adhesion force increases with lowered film hardness and surface roughness. Hardness and roughness are functions of substrate properties, film manufacture method, and thickness. Low adhesion forces and low contact resistance are both desirable and present a design tradeoff.

Pruitt, Beth L.

176

Contact Us (Affordable Care Act)  

MedlinePLUS

... content TOPICS Using the Marketplace Health Insurance Basics Contact Us Email Print By phone We’re available ... to see a list of local organizations with contact information, office hours, and types of help offered, ...

177

Conformally flat contact metric manifolds  

Microsoft Academic Search

.   A couple of classes of conformally flat contact metric manifolds have been classified. Conformally flat contact manifolds\\u000a have been characterized as hypersurfaces of 4-dimensional Kaehler Einstein (in particular, Calabi-Yau) manifolds.

Amalendu Ghosh; Themis Koufogiorgos; Ramesh Sharma

2001-01-01

178

Nanowire formation in macroscopic metallic contacts: quantum mechanical conductance tapping a table top  

Microsoft Academic Search

In this letter we show that quantum mechanical conductance is observed in nanowires formed by placing two wires of macroscopic dimensions in contact, making them vibrate so they get in and out of contact, and measuring the conductance response of such a system with an oscilloscope. We do this by tapping the table top on which the loose contact formed

J. L. Costa-Krämer; N. García; P. García-Mochales; P. A. Serena

1995-01-01

179

Spanish in Four Continents: Studies in Language Contact and Bilingualism.  

ERIC Educational Resources Information Center

|Papers on Spanish bilingualism and Spanish in contact with other languages include: "The Study of Language Contact: An Overview of the Issues" (Carmen Silva-Corvalan); "Language Mixture: Ordinary Processes, Extraordinary Results" (Sarah G. Thomason); "The Impact of Quichua on Verb Forms Used in Spanish Requests in Otavalo, Ecuador" (Joni Kay…

Silva-Corvalan, Carmen, Ed.

180

Contact Pressure Measurement System in Cross Wedge Rolling  

Microsoft Academic Search

In the cross wedge rolling process (CWR), plastic deformation is geared by a driving torque transmitted by friction on die surface. Friction plays a role which has to be further identified in this metal forming process. The local contact pressure between a cylindrical billet and flat dies seems to be a relevant parameter to characterize the severe contact conditions during

Philippe Mangin; Laurent Langlois; Régis Bigot

2011-01-01

181

Direct contact dissolution therapy.  

PubMed

Direct contact dissolution using MTBE is a safe, effective treatment for many patients with cholesterol gallstones when performed by clinicians experienced with this technique. This may be the treatment of choice for many patients at high risk for general anaesthesia or surgery. Cholecystostomy using local anaesthesia with subsequent stone extraction is an alternative requiring prolonged catheter drainage, and is associated with some risk and discomfort (Hawkyard et al, 1990). Most experts concur that laparoscopic cholecystectomy cannot be performed safely and comfortably without general anaesthesia under most circumstances. A second small population of patients are inordinately apprehensive about general anaesthesia or surgical removal of their gallbladder and refuse standard therapy in spite of recurrent biliary symptoms. Although direct contact dissolution is generally well tolerated, it may require several days of paramedical attention with medical supervision. This procedure will be most efficiently, effectively and comfortably performed by an experienced team and is, therefore, probably best provided by referral centres with physicians sufficiently interested in the treatment of biliary tract stone disease to develop expertise with this method. PMID:1486211

Thistle, J L

1992-11-01

182

Polymeric Materials for Contact Lenses  

Microsoft Academic Search

A contact lens is an optical device that is placed over the cornea of the eye in such a manner that the lens remains on the eye's surface throughout blinking. The main purpose of wearing a contact lens is to correct vision deficiencies; in this application they are called cosmetic lenses. Contact lenses can also be used medically for the

J. Singh; K. K. Agrawal

1992-01-01

183

Structure-based design of potent, conformationally constrained Smac mimetics.  

PubMed

A successful structure-based design and synthesis of a class of highly potent conformationally constrained Smac mimetics is described. The most potent compound has a Ki value of 25 nM binding to the XIAP BIR3 protein and is 23 times more potent than natural Smac peptides. These potent Smac mimetics can serve as powerful chemical and pharmacological tools to further elucidate the role of Smac and its cellular binding partners in apoptosis regulation and may be developed as a new class of anti-cancer drugs. PMID:15612682

Sun, Haiying; Nikolovska-Coleska, Zaneta; Yang, Chao-Yie; Xu, Liang; Liu, Meilan; Tomita, York; Pan, Hongguang; Yoshioka, Yoshiko; Krajewski, Krzysztof; Roller, Peter P; Wang, Shaomeng

2004-12-29

184

Surface coating for blood-contacting devices  

NASA Astrophysics Data System (ADS)

The major problems always encountered with the blood-contacting surfaces are their compatibility, contact blood damage, and thrombogenicity. Titanium nitride (TiN) is a hard, inert, ceramic material that is widely used in the engineering industry. TiN has been proven to be a good biomaterial in its crystalline form, in orthopedic, and in tissue implant applications. This dissertation describes a method to coat amorphous TiN on the blood-contacting surfaces of certain medical devices using the room-temperature sputtering process and to characterize, to test, and to evaluate the coating for a reliable, durable, and compatible blood-contacting surface The blood-compatibility aspects were evaluated with standard, established protocols and procedures to prove the feasibility. An amorphous TiN coating is developed, characterized, tested, and blood compatibility evaluated by applying to the blood-contacting surfaces of stainless steel, catheters, and blood filters. The flexibility characteristics were proven by applying it to the diaphragms of the pulsatile pneumatic ventricular assist device. The results show that amorphous titanium nitride is flexible and adherent to polymeric substrates like polyurethane and polyester. Blood compatibility evaluation showed comparable results with catheters and superior behavior with stainless steel and polyester filters. It is concluded that amorphous titanium nitride can be considered to be applied to the surfaces of some of the medical devices in order to improve blood compatibility.

Nair, Ajit Kumar Balakrishnan

185

Creation of Principally New Generation of Switching Technique Elements (Reed Switches) with Nanostructured Contact Surfaces  

NASA Astrophysics Data System (ADS)

The cycle of activities of the creation of principally new generation of reed switches with nanostructured contact surfaces was implemented. Experimental justification of the opportunity of reed switches creation with modified contact surface was given (instead of precious metals-based galvanic coating). Principally new technological process of modification of magnetically operated contacts contacting surfaces was developed, based on the usage of the ion-plasma methods of nanolayers and nanostructures forming having specified contact features.

Karabanov, S. M.; Zeltser, I. A.; Maizels, R. M.; Moos, E. N.; Arushanov, K. A.

2011-04-01

186

Proximity effect and multiple Andreev reflections in gold atomic contacts.  

PubMed

We investigate the electronic transport properties of gold point contacts with superconducting aluminum leads. The modifications induced by the proximity effect in the quasiparticle density of states at the contact region are measured by tunnel spectroscopy. The theory of transport through multiple Andreev reflections is extended to incorporate these effects and used to determine the number and transmission coefficients of the conduction channels in the contact regime. We find that the smallest contacts, formed by one gold atom between the electrodes, contribute one single channel to the transport with variable transmission T between 0.1 and 1. PMID:11177812

Scheer, E; Belzig, W; Naveh, Y; Devoret, M H; Esteve, D; Urbina, C

2001-01-01

187

Adaptive contact elements for three-dimensional explicit transient analysis  

SciTech Connect

A finite element method was developed for treating the mechanics of contact between deformable bodies. The method uses a family of adaptive interface elements, which were based on the penalty method, to handle the changing contact configurations that can occur between discretized contacting bodies. The nodal connectivity of these interface elements was allowed to change during the computations in order to accommodate finite sliding. The infusion of these elements in the interface satisfies the stress equilibrium condition during contact. Explicit forms for the nodal internal forces are presented. The methodology has been coded and several sample problems are presented. 23 refs., 29 figs., 6 tabs.

Kulak, R.F.

1989-01-01

188

40 CFR 463.10 - Applicability; description of the contact cooling and heating water subcategory.  

Code of Federal Regulations, 2011 CFR

...CONTINUED) EFFLUENT GUIDELINES AND STANDARDS PLASTICS MOLDING AND FORMING POINT SOURCE CATEGORY Contact...processes where process water comes in contact with plastic materials or plastic products for the purpose of heat transfer...

2011-07-01

189

Clinical contact preceding suicide.  

PubMed Central

Of the 400 consecutive completed suicides investigated over a 5-year period, 114 (28.5%) who had consulted a doctor in the week preceding death were specifically reviewed and compared with those who did not. The study comprised an analysis of the medical history, the scene of death and a complete autopsy with histological and toxicological examination and the identification of features which occurred more frequently in this group when compared with other suicides not contacting their doctors. Suicide-associated factors include psychiatric illness (58.8%), deteriorating health (16.7%), and a loss of spouse (7.0%); all these features were manifested by this group of suicides more frequently than by those who made no clinical contact (P < 0.001). A pre-indication of suicidal intention was made by 45% of these patients. This feature, as with previous attempts, occurred more commonly in patients who consulted a doctor (P < 0.001). Drug overdose was the most common suicidal method chosen (50.9%) and anti-depressants predominated (35%); 78% of those who overdosed ingested prescribed drugs. Poisoning was more common in this group (P < 0.001). Half of the victims committed suicide within 24 hours following consultation; of these, 51% overdosed on drugs with 61% of them ingesting their prescribed drugs. Of these 114 cases, the final consultation in 43% was to collect more drugs. All suicidal threats should be taken seriously, and particular care should be taken in prescribing and dispensing medication which may be fatal in overdose.

Obafunwa, J. O.; Busuttil, A.

1994-01-01

190

Contact angle and local wetting at contact line.  

PubMed

This theoretical study was motivated by recent experiments and theoretical work that had suggested the dependence of the static contact angle on the local wetting at the triple-phase contact line. We revisit this topic because the static contact angle as a local wetting parameter is still not widely understood and clearly known. To further clarify the relationship of the static contact angle with wetting, two approaches are applied to derive a general equation for the static contact angle of a droplet on a composite surface composed of heterogeneous components. A global approach based on the free surface energy of a thermodynamic system containing the droplet and solid surface shows the static contact angle as a function of local surface chemistry and local wetting state at the contact line. A local approach, in which only local forces acting on the contact line are considered, results in the same equation. The fact that the local approach agrees with the global approach further demonstrates the static contact angle as a local wetting parameter. Additionally, the study also suggests that the wetting described by the Wenzel and Cassie equations is also the local wetting of the contact line rather than the global wetting of the droplet. PMID:23066985

Li, Ri; Shan, Yanguang

2012-10-24

191

A Prototype Antifungal Contact Lens  

PubMed Central

Purpose. To design a contact lens to treat and prevent fungal ocular infections. Methods. Curved contact lenses were created by encapsulating econazole-impregnated poly(lactic-co-glycolic) acid (PLGA) films in poly(hydroxyethyl methacrylate) (pHEMA) by ultraviolet photopolymerization. Release studies were conducted in phosphate-buffered saline at 37°C with continuous shaking. The contact lenses and their release media were tested in an antifungal assay against Candida albicans. Cross sections of the pre- and postrelease contact lenses were characterized by scanning electron microscopy and by Raman spectroscopy. Results. Econazole-eluting contact lenses provided extended antifungal activity against Candida albicans fungi. Fungicidal activity varied in duration and effectiveness depending on the mass of the econazole-PLGA film encapsulated in the contact lens. Conclusions. An econazole-eluting contact lens could be used as a treatment for fungal ocular infections.

Ciolino, Joseph B.; Hudson, Sarah P.; Mobbs, Ashley N.; Hoare, Todd R.; Iwata, Naomi G.; Fink, Gerald R.

2011-01-01

192

Transfer form  

Cancer.gov

06/06 Transfer Investigational Agent Form This form is to be used for an intra-in stitutional transfer, one transfer/form. Cancer Therapy Evaluation Program Division of Cancer Treatment and Diagnosis National Cancer Institute National Institutes of

193

Impact of Random Dopant Fluctuation on Size-Dependence of Contact Resistance  

NASA Astrophysics Data System (ADS)

Reducing the size of semiconductor devices causes contact in deca-nano size. Substantial fluctuation of contact resistance is anticipated owing to the reduction of impurity atoms in the contact holes. In this study, the impact of the random dopant fluctuation on the contact resistance is revealed by three-dimensional device simulation with a Schottky contact model. The standard deviation of the contact resistance could become 50%, dominated by the number of impurity atoms in the depletion layer formed by the Schottky barrier. The average value of the contact resistance could increase as the impurity concentration decreases because of the reduction of the tunneling path.

Matsuzawa, Kazuya

2011-12-01

194

Induction of contact-dependent CD8(+) regulatory T cells through stimulation with staphylococcal and streptococcal superantigens.  

PubMed

The bacterial superantigen exotoxins of Staphylococcus aureus and Streptococcus pyogenes are potent stimulators of polyclonal T-cell proliferation. They are the causes of toxic shock syndrome but also induce CD25(+) ?FOXP3(+) regulatory cells in the CD4 compartment. Several studies have recently described different forms of antigen-induced regulatory CD8(+) T cells in the context of inflammatory diseases and chronic viral infections. In this paper we show that bacterial superantigens are potent inducers of human regulatory CD8(+) T cells. We used four prototypic superantigens of S. aureus (toxic shock syndrome toxin-1 and staphylococcal enterotoxin A) and Str. pyogenes (streptococcal pyrogenic exotoxins A and K/L). At concentrations below 1?ng/ml each toxin triggers concentration-dependent T-cell receptor V?-specific expression of CD25 and FOXP3 on CD8(+) T cells. This effect is independent of CD4(+) T-cell help but requires antigen-presenting cells for maximum effect. The cells also express the activation/regulatory markers cytotoxic T-lymphocyte antigen-4 and glucocorticoid-induced tumour necrosis factor receptor-related protein and skin homing adhesins CD103 and cutaneous lymphocyte-associated antigen. Superantigen-induced CD25(+) ?FOXP3(+) ?CD8(+) T cells were as potent as freshly prepared naturally occurring CD4(+) regulatory T cells in suppressing proliferation of CD4(+) ?CD25(-) T cells in response to anti-CD3 stimulation. Although superantigen-induced CD8(+) ?CD25(+) FOXP3(+) express interleukin-10 and interferon-? their suppressive function is cell contact dependent. Our findings indicate that regulatory CD8(+) T cells may be a feature of acute bacterial infections contributing to immune evasion by the microbe and disease pathogenesis. The presence and magnitude of regulatory CD8(+) T-cell responses may represent a novel biomarker in such infections. Superantigen-induced regulatory CD8(+) T cells also have therapeutic potential. PMID:22043981

Taylor, Amanda L; Cross, Elizabeth L A; Llewelyn, Martin J

2012-02-01

195

Induction of contact-dependent CD8+ regulatory T cells through stimulation with staphylococcal and streptococcal superantigens*  

PubMed Central

The bacterial superantigen exotoxins of Staphylococcus aureus and Streptococcus pyogenes are potent stimulators of polyclonal T-cell proliferation. They are the causes of toxic shock syndrome but also induce CD25+ FOXP3+ regulatory cells in the CD4 compartment. Several studies have recently described different forms of antigen-induced regulatory CD8+ T cells in the context of inflammatory diseases and chronic viral infections. In this paper we show that bacterial superantigens are potent inducers of human regulatory CD8+ T cells. We used four prototypic superantigens of S. aureus (toxic shock syndrome toxin-1 and staphylococcal enterotoxin A) and Str. pyogenes (streptococcal pyrogenic exotoxins A and K/L). At concentrations below 1 ng/ml each toxin triggers concentration-dependent T-cell receptor V?-specific expression of CD25 and FOXP3 on CD8+ T cells. This effect is independent of CD4+ T-cell help but requires antigen-presenting cells for maximum effect. The cells also express the activation/regulatory markers cytotoxic T-lymphocyte antigen-4 and glucocorticoid-induced tumour necrosis factor receptor-related protein and skin homing adhesins CD103 and cutaneous lymphocyte-associated antigen. Superantigen-induced CD25+ FOXP3+ CD8+ T cells were as potent as freshly prepared naturally occurring CD4+ regulatory T cells in suppressing proliferation of CD4+ CD25? T cells in response to anti-CD3 stimulation. Although superantigen-induced CD8+ CD25+ FOXP3+ express interleukin-10 and interferon-? their suppressive function is cell contact dependent. Our findings indicate that regulatory CD8+ T cells may be a feature of acute bacterial infections contributing to immune evasion by the microbe and disease pathogenesis. The presence and magnitude of regulatory CD8+ T-cell responses may represent a novel biomarker in such infections. Superantigen-induced regulatory CD8+ T cells also have therapeutic potential.

Taylor, Amanda L; Cross, Elizabeth L A; Llewelyn, Martin J

2012-01-01

196

A Potent Cell-active Allosteric Inhibitor of Murine DNA Cytosine C5 Methyltransferase  

Microsoft Academic Search

The major DNA cytosine methyltransferase isoform in mouse erythroleukemia cells, Dnmt1, exhibits potent dead-end inhibition with a single-stranded nucleic acid by binding to an allosteric site on the enzyme. The pre- viously reported substrate inhibition with double- stranded substrates also involves binding to an allo- steric site. Thus, both forms of inhibition involve ternary enzyme-DNA-DNA complexes. The inhibition potency of

James Flynn; Jing-Yuan Fang; Judy A. Mikovits; Norbert O. Reich

2003-01-01

197

Convergent synthesis of the BCDEFGHIJ-ring polyether core of gambieric acids, potent antifungal polycyclic ethers  

Microsoft Academic Search

A convergent synthesis of the nonacyclic BCDEFGHIJ-ring polyether core of gambieric acids, potent antifungal polycyclic ether marine natural products, has been achieved. The present synthesis involved as key features: (i) convergent union of the BCD- and GHIJ-ring fragments through esterification, (ii) construction of the E-ring as a lactone form via reductive acetylation, (iii) stereoselective allylation to establish the C26 stereocenter,

Kazushi Sato; Makoto Sasaki

2007-01-01

198

Clean transfer of graphene and its effect on contact resistance  

NASA Astrophysics Data System (ADS)

We demonstrate herein an effective method of forming a high-quality contact between metal and graphene on a wafer as large as 6 in. This gold-assisted transfer method producing no polymer residue on the graphene surface is introduced, and then the gold film is used directly as an electrode to form the transfer length method pattern for calculating the contact resistance. The graphene surface obtained using the gold-assisted transfer method is clean and uniform without residue or contamination, and its contact resistance is at least 60% lower than that obtained using the conventional poly(methyl methacrylate) assisted transfer method.

Lee, Jooho; Kim, Yongsung; Shin, Hyeon-Jin; Lee, ChangSeung; Lee, Dongwook; Moon, Chang-Yul; Lim, Juhwan; Chan Jun, Seong

2013-09-01

199

Electroless copper contacts for low concentration silicon solar cells  

NASA Astrophysics Data System (ADS)

The purpose of this work was to form highly conductive and low cost copper contacts on shallow and hence optically thin p-n junctions (<0.4?m deep) on a randomly textured solar cells for low concentration PV (LCPV) module. At first, window formation process in SiNx by femtosecond UV laser pulse ablation on the textured surface was introduced. Then nickel silicide contacts were formed and subsequent contact thickening was performed by electroless copper plating in an industrially feasible way. Characteristics of finished solar cells were investigated in this work. The cells were successfully implemented into the low concentration (C=15x) PV module.

Janušonis, Julius; Galdikas, Algirdas; Juzumas, Valdemaras; Jaramin?, Lina; Lukštaraupis, Tomas; Andrijauskas, Darius; Janušonien?, Vida; Janušonis, Darius; Ulbikas, Juras

2012-10-01

200

Bicycloorthocarboxylate convulsants. Potent GABAA receptor antagonists.  

PubMed

4-t-Butyl-1-(4-bromophenyl)-bicycloorthocarboxylate antagonizes gamma-aminobutyric acid (GABA)-mediated relaxation at a functional insect nerve-muscle synapse, mimicking the action of picrotoxinin, suggesting that it causes GABA antagonism through blockade of the chloride ionophore. It is also a potent GABAA receptor antagonist, inhibiting the binding of [35S]t-butyl-bicyclophosphorothionate ([35S]TBPS) to EDTA/water-dialyzed human brain P2 membranes. Structure-activity relationships of 74 1,4-bis-substituted bicycloorthocarboxylates, mostly new compounds, reveal that for high potency as a GABAA receptor antagonist the optimal 4-substituent is a C4 to C6 branched chain alkyl or cycloalkyl group (e.g., t-butyl, s-butyl, or cyclohexyl) and the optimal 1-substituent is a phenyl moiety with one or more electron-withdrawing groups (e.g., 4-cyano, 4-bromo, 4-chloro, 3,4-dichloro, or pentafluoro). Bicycloorthocarboxylate inhibitors of [35S]TBPS binding with IC50 values of 5-10 nM exceed by several-fold the potency of any GABAA receptor antagonist previously reported. The 4-t-butyl-1-(4-azidophenyl) analog, synthesized as a candidate photoaffinity label, gives an IC50 of 315 nM. The potency of bicycloorthocarboxylates for decreasing [35S]TBPS binding generally correlates with their toxicity, i.e., compounds without inhibitory activity in this brain receptor assay are of low toxicity on intraperitoneal administration to mice, and the analogs most potent as inhibitors are generally those most toxic to mice (e.g., IC50 of 5 nM and LD50 of 0.06 mg/kg for 4-t-butyl-1-(4-cyanophenyl)-bicycloorthocarboxylate). The effects of phenyl substituents on the potency of the orthobenzoates as GABAA receptor antagonists are similar to those on toxicity. In contrast to the 1-substituted phenyl compounds, 4-t-butyl-1-ethynyl-bicycloorthocarboxylate and its 4-i-propyl analog are very toxic (LD50 0.4-2 mg/kg) but have only moderate inhibitory potency (IC50 480-2900 nM), a pattern noted for many 1-alkyl-bicycloorthocarboxylates, suggesting that even within this series there may be different types of receptor-inhibitor interactions. 1-(4-Chlorophenyl)-4-cyclohexyl-bicycloorthocarboxylate is particularly sensitive to oxidative detoxification based on its 10-fold synergism of toxicity by piperonyl butoxide and marked potency loss in a coupled [35S]TBPS receptor/microsomal oxidase assay. Some benzodiazepines and phenobarbital protect against poisoning by 1-(4-bromophenyl)- and 1-ethynyl-4-t-butyl-bicycloorthocarboxylates and their 1-(4-bromophenyl)-4-cyclohexyl analog.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2993847

Casida, J E; Palmer, C J; Cole, L M

1985-09-01

201

Contact Mechanisms and Contact Resistance Characteristics of Solid Tin and Plated Tin Contacts Used for Connectors  

NASA Astrophysics Data System (ADS)

Tin and its alloys have been applied for the plating of electrical contacts for low electrical power conditions. In particular, tin-plated contacts are widely used as connector contacts in automotive applications and as make-break contacts in keyboard switches. In the relationship between contact resistance (R) and contact load (W) for both solid and plated tin, singularities have been found. Previously established and well known theories on the deformation of contact interfaces cannot explain these singularities. In this study, to clarify these singularities, and to obtain a contact model explaining this phenomenon, contact traces for contact load were examined by SEM and STM. The obtained microscopic images indicated piling-up at the periphery of the contact area for both solid and plated tin. In this case the contact configuration comprised a platinum probe with a hemispherical tip surface and a flat tin surface for both solid and plated. When the probe was loaded, this tip of the probe sank into the soft tin surface owing to its lower hardness. In case of solid tin, the sinking of the probe surface into the tin surface causes piling-up around the periphery of the contact trace. In this deformation process, since the periphery of the indentation of the indented contact area severely slid against the surface of the platinum probe while applying a contact load, the contact resistance rapidly decreased with load. In this case, the center portion of the true contact area was not affected mechanically; thus, the surface film on the bottom portion of the deformed of the flat surface did not break down mechanically. On the other hand, in the case of a tin plated surface, similar piling up occurred; however, it was accompanied by scattering and separation of tin crystal grains from the surface. As a result of this process, a decrease in contact resistance similar to that for the solid tin occurred. Since the piling-up of the contact surface is a very important process in the application of connectors, the above-mentioned unusual characteristics were clarified in this study.

Tamai, Terutaka; Sawada, Shigeru; Hattori, Yasuhiro

202

FORMING PROTECTIVE FILMS ON METAL  

DOEpatents

Methods are described of inhibiting the corrosion of ferrous metal by contact with heavy liquid metals such as bismuth and gallium at temperatures above 500 icient laborato C generally by bringing nltrogen and either the metal zirconium, hafnium, or titanium into reactlve contact with the ferrous metal to form a thin adherent layer of the nitride of the metal and thereafter maintaining a fractional percentage of the metal absorbed in the heavy liquid metal in contact with the ferrous metal container. The general purpose for uslng such high boiling liquid metals in ferrous contalners would be as heat transfer agents in liquid-metal-fueled nuclear reactors.

Gurinsky, D.H.; Kammerer, O.F.; Sadofsky, J.; Weeks, J.R.

1958-12-16

203

Graphite-Graphene Contact Resistance  

NASA Astrophysics Data System (ADS)

Exploiting the exceptional electronic properties of graphene has been attempted in several applications. However, graphene based applications still lag behind conventional electronics due, in part, to the highly resistive metal-graphene junction. For example, graphene based RF transistors suffer a diminished (fmax) due to highly resistive source-drain contacts (>200 ?- ?m). Reducing this paracistic resistance can yield substantial improvement in device performance for transistors and many other applications. To achieve this, we create an electrical contact to graphene using mesoscopic, exfoliated graphite (10 - 20 nm thick). We fabricate graphite-graphene contacts by transferring pre-defined graphite contacts to graphene on silicon dioxide. Experimental measurement has shown the contact resistance to be <50 ?- ?m, a four-fold improvement over conventional contacts to graphene.

Chari, Tarun; Dean, Cory; Meric, Inanc; Wang, Lei; Shepard, Ken

2013-03-01

204

Application of power loss calculation to estimate the specific contact resistance of the screen-printed silver ohmic contacts of the large area silicon solar cells  

Microsoft Academic Search

The establishment of a suitable contact formation methodology is a critical part of the technological development of any metal-to-semiconductor\\u000a contact structure. Many test structures and methodologies have been proposed to estimate the specific contact resistance (?c) of the planar ohmic contacts formed on the heavily doped semiconductor surface. These test structures are usually processed\\u000a on the same wafer to monitor

P. N. Vinod

2007-01-01

205

POTENT INHIBITION OF HUMAN AP ENDONUCLEASE 1 BY ARYLSTIBONIC ACIDS  

PubMed Central

Human apurinic/apyrimidinic endonuclease (Ape1) plays an important role by processing the >10,000 highly toxic abasic sites generated in the genome of each cell every day. Ape1 has recently emerged as a target for inhibition as its overexpression in tumors has been linked with poor response to both radiation and chemotherapy and lower overall patient survival. Inhibition of Ape1 using siRNA or the expression of a dominant-negative form of the protein have been shown to sensitize cells to DNA-damaging agents, including various chemotherapeutic agents. However, potent small molecule inhibitors of Ape1 remain to be found. To this end, we screened Ape1 against the NCI Diversity Set of small molecules and discovered aromatic nitroso, carboxylate, sulfonamide and arylstibonic acid compounds with micromolar affinities for the protein. A further screen of a 37-compound arylstibonic acid sublibrary identified ligands with IC50 values in the range 4 to 300 nM. The negatively charged stibonic acids act by a partial-mixed mode, and likely serve as DNA phosphate mimics. These compounds provide a useful scaffold for development of chemotherapeutic agents against Ape1.

Seiple, Lauren A.; Cardellina, John H.; Akee, Rhone; Stivers, James T.

2009-01-01

206

Contact lens correction of presbyopia.  

PubMed

The ageing population highlights the need to provide effective optical solutions for presbyopic contact lens wearers. However, data gathered from annual contact lens fitting surveys demonstrate that fewer than 40% of contact lens wearers over 45 years of age (virtually all of whom can be presumed to suffer a partial or complete loss of accommodation) are prescribed a presbyopic correction. Furthermore, monovision is prescribed as frequently as multifocal lenses. These observations suggest that an optimal solution to the contact lens correction of presbyopia remains elusive. PMID:19535284

Morgan, Philip B; Efron, Nathan

2009-06-16

207

Thermal and Electrical Contact Conductance Studies.  

National Technical Information Service (NTIS)

Prediction of electrical and thermal contact resistance for pressed, nominally flat contacts is complicated by the large number of variables which influence contact formation. This is reflected in experimental results as a wide variation in contact resist...

S. W. Vansciver M. Nilles

1985-01-01

208

Structures of Potent Selective Peptide Mimetics Bound to Carboxypeptidase B  

SciTech Connect

This article reports the crystal structures of inhibitors of the functional form of thrombin-activatable fibrinolysis inhibitor (TAFIa). In vivo experiments indicate that selective inhibitors of TAFIa would be useful in the treatment of heart attacks. Since TAFIa rapidly degrades in solution, the homologous protein porcine pancreatic carboxypeptidase B (pp-CpB) was used in these crystallography studies. Both TAFIa and pp-CpB are zinc-based exopeptidases that are specific for basic residues. The final development candidate, BX 528, is a potent inhibitor of TAFIa (2 nM) and has almost no measurable effect on the major selectivity target, carboxypeptidase N. BX 528 was designed to mimic the tripeptide Phe-Val-Lys. A sulfonamide replaces the Phe-Val amide bond and a phosphinate connects the Val and Lys groups. The phosphinate also chelates the active-site zinc. The electrostatic interactions with the protein mimic those of the natural substrate. The primary amine in BX 528 forms a salt bridge to Asp255 at the base of the S1 pocket. The carboxylic acid interacts with Arg145 and the sulfonamide is hydrogen bonded to Arg71. Isopropyl and phenyl groups replace the side chains of Val and Phe, respectively. A series of structures are presented here that illustrate the evolution of BX 528 from thiol-based inhibitors that mimic a free C-terminal arginine. The first step in development was the replacement of the thiol with a phosphinate. This caused a precipitous drop in binding affinity. Potency was reclaimed by extending the inhibitors into the downstream binding sites for the natural substrate.

Adler, M.; Buckman, B.; Bryant, J.; Chang, Z.; Chu, K.; Emayan, K.; Hrvatin, P.; Islam, I.; Morser, J.; Sukovich, D.; West, C.; Yuan, S.; Whitlow, M.

2009-05-11

209

Contact and thermal analysis of bronze and steel machined surfaces in sliding contact  

Microsoft Academic Search

Between engineering components in sliding contact there are usually small real contact areas inside the nominal contact area. The real contact pressure frequently is in the range of the plastic limit pressure.The effect of different machining processes (grinding, milling, spark-erosion and superfinising) on the contact parameters (real contact areas, contact pressure distribution and contact temperature) were analysed and compared between

Béla Pálasti Kovács

1998-01-01

210

Fluorocyclopentenyl-cytosine with broad spectrum and potent antitumor activity.  

PubMed

On the basis of the potent biological activity of cyclopentenyl-pyrimidines, fluorocyclopentenyl-pyrimidines were designed and synthesized from D-ribose. Among these, the cytosine derivative 5a showed highly potent antigrowth effects in a broad range of tumor cell lines and very potent antitumor activity in a nude mouse tumor xenograft model implanted with A549 human lung cancer cells. However, its 2'-deoxycytidine derivative 5b did not show any antigrowth effects, indicating that 2'-hydroxyl group is essential for the biological activity. PMID:22524616

Choi, Won Jun; Chung, Hwa-Jin; Chandra, Girish; Alexander, Varughese; Zhao, Long Xuan; Lee, Hyuk Woo; Nayak, Akshata; Majik, Mahesh S; Kim, Hea Ok; Kim, Jin-Hee; Lee, Young B; Ahn, Chang H; Lee, Sang Kook; Jeong, Lak Shin

2012-05-01

211

Similarity searching for potent compounds using feature selection.  

PubMed

In similarity searching, compound potency is usually not taken into account. Given a set of active reference compounds, similarity to database molecules is calculated using different metrics without considering compound potency as a search parameter. Herein, we introduce a feature selection method for fingerprint similarity searching to maximize compound recall and preferentially detect potent compounds. On the basis of training examples, fingerprint features are selected that identify potent compounds and produce high recall. Using the reduced fingerprint representations, potent hits are preferentially detected, even if reference compounds have only moderate or low potency. Small sets of simple chemical features are found to yield high search performance. PMID:23808911

Vogt, Martin; Bajorath, Jürgen

2013-07-09

212

An Instrument to Measure Ice Nucleation in the Contact Mode  

NASA Astrophysics Data System (ADS)

Understanding how ice is formed in clouds is a major outstanding challenge in understanding and predicting global climate change. Of the known ice formation pathways in the atmosphere (homogeneous, deposition, immersion, condensation, and contact), the least understood is contact nucleation. Measurement of an aerosol particle's effectiveness in the contact mode requires that the particle be brought into contact with the surface of a supercooled water drop and the subsequent nucleation event (if any) detected. We describe an instrument capable of measuring ice nucleation catalyzed via aerosol particles in the contact mode. The essence of the apparatus is an electric field, created using parallel, conducting plates. The electric field forces charged aerosols into contact with a supercooled water drop held on the temperature controlled lower plate. The size of particles acting as contact nuclei can be determined from the time required for particles to traverse the vertical extent of the chamber. Nucleation events are detected using a laser, which is focused through the droplet onto a photodiode. When the droplet freezes, the voltage across the photodiode changes due to the change in transmitted/scattered laser light. This design allows us to control the temperature of the supercooled water drop as well as measure contact nucleation activity of a distribution of aerosol particles. Preliminary results using Arizona Test Dust have shown that the apparatus successfully allows ice nucleation in the contact mode to be measured.

Bunker, K. W.; Cantrell, W. H.

2009-12-01

213

Contact modeling for robotics applications  

SciTech Connect

At Sandia National Laboratories (SNL), the authors are developing the ability to accurately predict motions for arbitrary numbers of bodies of arbitrary shapes experiencing multiple applied forces and intermittent contacts. In particular, the authors are concerned with the simulation of systems such as part feeders or mobile robots operating in realistic environments. Preliminary investigation of commercial dynamics software packages led them to the conclusion that they could use commercial software to provide everything they needed except for the contact model. They found that ADAMS best fit their needs for a simulation package. To simulate intermittent contacts, they need collision detection software that can efficiently compute the distances between non-convex objects and return the associated witness features. They also require a computationally efficient contact model for rapid simulation of impact, sustained contact under load, and transition to and from contact conditions. This paper provides a technical review of a custom hierarchical distance computation engine developed at Sandia, called the C-Space Toolkit (CSTk). In addition, they describe an efficient contact model using a non-linear damping term developed by SNL and Ohio State. Both the CSTk and the non-linear damper have been incorporated in a simplified two-body testbed code, which is used to investigate how to correctly model the contact using these two utilities. They have incorporated this model into the ADAMS software using the callable function interface. An example that illustrates the capabilities of the 9.02 release of ADAMS with their extensions is provided.

Lafarge, R.A.; Lewis, C.

1998-08-01

214

Creativity, Culture Contact, and Diversity  

Microsoft Academic Search

Recent trends in the understanding of culture contact, with concepts such as hybridization, cosmopolitanism, and cultural innovation, open up the possibility of a new understanding of human interaction. While the social imaginary is rich with images of conflict resulting from culture contact, images of creativity are far rarer. We propose the creation of an extensive research project to document cultural

Alfonso Montuori; Hillary Stephenson

2010-01-01

215

Children's Contact with Absent Parents.  

ERIC Educational Resources Information Center

|Investigated frequency of contact between children and biological parents who were separated. Used data from 1981 national survey to examine effects of living arrangements and other family characteristics on cross-household ties between children and parents. Found frequent contact occurring for children who had recently lived with absent parent…

Seltzer, Judith A.; Bianchi, Suzanne M.

1988-01-01

216

Discrimination against contact lens wearers.  

PubMed

Employers' attitudes toward the use of contact lenses at work have become less discriminatory as lenses have improved and numerous studies have demonstrated their safety, provided that additional personal protective equipment is used when necessary. In 1994, the Occupational Safety and Health Administration published its relevant Standard (29 CFR 1910), stating that "contact lenses do not pose additional hazards to the wearer...". Accommodations required by wearers of contact lenses must comply with Title I of the Americans with Disabilities Act. However, many companies still oppose their use. The recently published policy of the American College of Occupational and Environmental Medicine and the American Academy of Ophthalmology on the use of contact lenses should lead to their wider acceptance. Elements of a corporate contact lens policy are outlined. International aspects are summarized as well. PMID:9800172

Blais, B R

1998-10-01

217

Contact sensing from force measurements  

SciTech Connect

This article addresses contact sensing (i.e., the problem of resolving the location of a contact, the force at the interface, and the moment about the contact normals). Called `intrinsic` contact sensing for the use of internal force and torque measurements, this method allows for practical devices that provide simple, relevant contact information in practical robotic applications. Such sensors have been used in conjunction with robot hands to identify objects, determine surface friction, detect slip, augment grasp stability, measure object mass, probe surfaces, and control collision and for a variety of other useful tasks. This article describes the theoretical basis for their operation and provides a framework for future device design. 24 refs., 12 figs., 3 tabs.

Bicchi, A.; Salisbury, J.K.; Brock, D.L. [Massachusetts Inst. of Technology, Cambridge (United States)

1993-06-01

218

Spray forming  

Microsoft Academic Search

Spray forming is a relatively new manufacturing process for near net shape preforms in a wide variety of alloys. Spray formed materials have a characteristic equiaxed microstructure with small grain sizes, low levels of solute partitioning, and inhibited coarsening of secondary phases. After consolidation to full density, spray formed materials have consistently shown properties superior to conventionally cast materials, and

P. S. Grant

1995-01-01

219

Potent antimicrobial small molecules screened as inhibitors of tyrosine recombinases and Holliday junction-resolving enzymes.  

PubMed

Holliday junctions (HJs) are critical intermediates in many recombination-dependent DNA repair pathways. Our lab has previously identified several hexameric peptides that target HJ intermediates formed in DNA recombination reactions. One of the most potent peptides, WRWYCR, is active as a homodimer and has shown bactericidal activity partly because of its ability to interfere with DNA repair proteins that act upon HJs. To increase the possibility of developing a therapeutic targeting DNA repair, we searched for small molecule inhibitors that were functional surrogates of the peptides. Initial screens of heterocyclic small molecule libraries resulted in the identification of several N-methyl aminocyclic thiourea inhibitors. Like the peptides, these inhibitors trapped HJs formed during recombination reactions in vitro, but were less potent than the peptides in biochemical assays and had little antibacterial activity. In this study, we describe the screening of a second set of libraries containing somewhat larger and more symmetrical scaffolds in an effort to mimic the symmetry of a WRWYCR homodimer and its target. From this screen, we identified several pyrrolidine bis-cyclic guanidine inhibitors that also interfere with processing of HJs in vitro and are potent inhibitors of Gram-negative and especially Gram-positive bacterial growth. These molecules are proof-of-principle of a class of compounds with novel activities, which may in the future be developed into a new class of antibiotics that will expand the available choices for therapy against drug-resistant bacteria. PMID:21938393

Rideout, Marc C; Boldt, Jeffrey L; Vahi-Ferguson, Gabriel; Salamon, Peter; Nefzi, Adel; Ostresh, John M; Giulianotti, Marc; Pinilla, Clemencia; Segall, Anca M

2011-09-22

220

Producing thin film photovoltaic modules with high integrity interconnects and dual layer contacts  

DOEpatents

High performance photovoltaic modules are produced with improved interconnects by a special process. Advantageously, the photovoltaic modules have a dual layer back (rear) contact and a front contact with at least one layer. The front contact and the inner layer of the back contact can comprise a transparent conductive oxide. The outer layer of the back contact can comprise a metal or metal oxide. The front contact can also have a dielectric layer. In one form, the dual layer back contact comprises a zinc oxide inner layer and an aluminum outer layer and the front contact comprises a tin oxide inner layer and a silicon dioxide dielectric outer layer. One or more amorphous silicon-containing thin film semiconductors can be deposited between the front and back contacts. The contacts can be positioned between a substrate and an optional superstrate. During production, the transparent conductive oxide layer of the front contact is scribed by a laser, then the amorphous silicon-containing semiconductors and inner layer of the dual layer back contact are simultaneously scribed and trenched (drilled) by the laser and the trench is subsequently filled with the same metal as the outer layer of the dual layer back contact to provide a superb mechanical and electrical interconnect between the front contact and the outer layer of the dual layer back contact. The outer layer of the dual layer back contact can then be scribed by the laser. For enhanced environmental protection, the photovoltaic modules can be encapsulated.

Jansen, Kai W. (Lawrenceville, NJ); Maley, Nagi (Exton, PA)

2000-01-01

221

Producing thin film photovoltaic modules with high integrity interconnects and dual layer contacts  

DOEpatents

High performance photovoltaic modules are produced with improved interconnects by a special process. Advantageously, the photovoltaic modules have a dual layer back (rear) contact and a front contact with at least one layer. The front contact and the inner layer of the back contact can comprise a transparent conductive oxide. The outer layer of the back contact can comprise a metal or metal oxide. The front contact can also have a dielectric layer. In one form, the dual layer back contact comprises a zinc oxide inner layer and an aluminum outer layer and the front contact comprises a tin oxide inner layer and a silicon dioxide dielectric outer layer. One or more amorphous silicon-containing thin film semiconductors can be deposited between the front and back contacts. The contacts can be positioned between a substrate and an optional superstrate. During production, the transparent conductive oxide layer of the front contact is scribed by a laser, then the amorphous silicon-containing semiconductors and inner layer of the dual layer back contact are simultaneously scribed and trenched (drilled) by the laser and the trench is subsequently filled with the same metal as the outer layer of the dual layer back contact to provide a superb mechanical and electrical interconnect between the front contact and the outer layer of the dual layer back contact. The outer layer of the dual layer back contact can then be scribed by the laser. For enhanced environmental protection, the photovoltaic modules can be encapsulated.

Jansen, Kai W. (Lawrenceville, NJ); Maley, Nagi (Exton, PA)

2001-01-01

222

Contact Interface Verification for DYNA3D Scenario 2: Multi-Surface Contact  

SciTech Connect

A suite of test problems has been developed to examine contact behavior within the nonlinear, three-dimensional, explicit finite element analysis (FEA) code DYNA3D (Lin, 2005). The test problems use multiple interfaces and a combination of enforcement methods to assess the basic functionality of the contact algorithms. The results from the DYNA3D analyses are compared to closed form solutions to verify the contact behavior. This work was performed as part of the Verification and Validation efforts of LLNL W Program within the NNSA's Advanced Simulation and Computing (ASC) Program. DYNA3D models the transient dynamic response of solids and structures including the interactions between disjoint bodies (parts). A wide variety of contact surfaces are available to represent the diverse interactions possible during an analysis, including relative motion (sliding), separation and gap closure (voids), and fixed relative position (tied). The problem geometry may be defined using a combination of element formulations, including one-dimensional beam and truss elements, two-dimensional shell elements, and three-dimensional solid elements. Consequently, it is necessary to consider various element interactions during contact. This report and associated test problems examine the scenario where multiple bodies interact with each other via multiple interfaces. The test problems focus on whether any ordering issues exist in the contact logic by using a combination of interface types, contact enforcement options (i.e., penalty, Lagrange, and kinematic), and element interactions within each problem. The influence of rigid materials on interface behavior is also examined. The companion report (McMichael, 2006) and associated test problems address the basic contact scenario where one contact surface exists between two disjoint bodies. The test problems are analyzed using version 5.2 (compiled on 12/22/2005) of DYNA3D. The analytical results are used to form baseline solutions for subsequent regression testing. In section 2, the test problems are presented, and the static solution is developed for two idealized systems. Section 3 describes the finite element representation of the generic problem, including the interface combinations considered. The verification criteria and expected results are presented next in section 4. Section 5 discusses the numerical results obtained from each test problem. Finally, section 6 summarizes the observed interface behavior.

McMichael, L D

2006-05-10

223

Potent and selective inhibitors of the proteasome: Dipeptidyl boronic acids  

Microsoft Academic Search

Potent and selective dipeptidyl boronic acid proteasome inhibitors are described. As compared to peptidyl aldehyde compounds, boronic acids in this series display dramatically enhanced potency. Compounds such as 15 are promising new therapeutics for treatment of cancer and inflammatory diseases.

Julian Adams; Mark Behnke; Shaowu Chen; Amy A. Cruickshank; Lawrence R. Dick; Louis Grenier; Janice M. Klunder; Yu-Ting Ma; Louis Plamondon; Ross L. Stein

1998-01-01

224

Synthesis of potent antitumor and antiviral benzofuran derivatives.  

PubMed

A new series of potent antitumor and antiviral benzofuran derivatives was synthesized by the reaction of the furochromone-6-carboxaldehydes 1 and 2 with different heterocyclic amines to yield the benzofuran-5-carbonyl derivatives 4-11. The synthesized compounds 1, 3-11 were tested against twelve different human cancer cell lines and all of the compounds were more potent than the comparative standards. The HIV inhibitory activity of the tested compounds 1, 3-11 showed that they have higher potency than Atevirdine. Moreover, compound 6 was significantly potent with wider therapeutic index. The HIV-1 RT inhibitory activity showed that compounds 10, 11, 3 and 4 were notably potent but with lower therapeutic index than Atevirdine. The HCV NS3-4A protease inhibitor activity of the tested compounds revealed that they have weaker potency and less therapeutic index than VX-950, although compounds 1, 4, 9 and 6, respectively exhibited significant activity. PMID:19345581

Galal, Shadia A; Abd El-All, Amira S; Abdallah, Mohamed M; El-Diwani, Hoda I

2009-03-21

225

CORRIGENDUM: Multiscale electrical contact resistance in clustered contact distribution Multiscale electrical contact resistance in clustered contact distribution  

NASA Astrophysics Data System (ADS)

The authors wish to explain the similarity between some figures in the above paper (hereafter called the JPD paper) and in their other publication, Lee S, Jang Y H and Kim W 2008 Effects of nanosized contact spots on thermal contact resistance J. Appl. Phys.103 074308 (hereafter called the JAP paper), and to explain the differences between the two papers, which are not explicitly stated in the JPD paper. The main objective of the JAP paper is to calculate the thermal contact resistance of the nanosized contact spots in multiscale contact. During the process of multiscale analysis, the thermal conductivity varies, especially below the phonon mean free path. The JPD paper deals with the electrical contact resistance in the multiscale contact distribution with an assumption of constant electrical resistivity, which is known as a different kind of physics in a larger characteristic length scale. There are similar figures in the JPD paper and the JAP paper: figures 6, 7 and 8 in the JPD paper and figures 3, 4 and 5 in the JAP paper. Two research works were performed on the basis of a specific microcontact distribution. In the JAP paper, the scale of the contact distribution is in the range of the phonon mean free path of Si, which is a very small size of contact distribution. In the JPD paper, the scale of contact distribution is in the continuum scale, which is larger than the phonon mean free path. In addition, due to the characteristics of a fractal surface which repeatedly generates a similar shape of contact distribution in the different length scales, the shape of contact distribution looks similar, but the total sizes of domain in the JPD and JAP figures are different. The projected areas L × L of fractal surface of the JAP paper and JPD paper are 10 ?m × 10 ?m and 10 mm × 10 mm, respectively. The length scale is already stated in the JAP paper, but not in the JPD paper. Thus, we have to state that the figures were adapted from the JAP paper without clear attribution and that credit should be given to the original source of the images. Most significantly, the two most important features of the two works are based on totally different physics and the calculation methods for contact resistance. The text of section 4.3 of the JPD paper should be modified. The left column of page 5 and the first two lines of the right column should be replaced by the following text. The projected area of a self-affine fractal surface is plotted in figure 6. In order to find the microcontact spot distribution from the fractal surface, numerical simulations are applied to the model of multiscale rough surface. Several contact models are constructed according to the resolution of 1/24 to 1/28. Figure 7 shows a typical finite element model in which the rough elastic surface is in contact with a perfectly flat rigid surface. Due to the fine meshes in the contact interface, strong mesh gradations are required. The contact simulation enforcing the impenetrability constraint on the mating surfaces is performed by a commercial finite element package, Abaqus/HKS ([22] of the JPD paper). The resulting microcontact spot distributions for different resolution of the rough surface are obtained in figure 8. As reported by Borri-Brunetto et al ([23] of the JPD paper), the actual contact area decreases and the number of contact spots increases as the resolution of the discretization escalates. A more detailed description for the model can be obtained in the JAP paper.

Lee, Sangyoung; Cho, Hyun; Jang, Yong Hoon

2010-06-01

226

Biological evaluation and molecular modelling study of podophyllotoxin derivatives as potent inhibitors of tubulin polymerization.  

PubMed

Microtubules are considered as important targets of anticancer therapy. Podophyllotoxin and its structural derivative are major microtubule-interfering agents with potent anticancer activity. In this study, we reported the anticancer effects of 10 representative podophyllotoxin derivatives on a panel of four human cancer cell lines. Deoxypodophyllotoxin (6b) and ?-apopicropodophyllotoxin (6g) elicited strong antiproliferative effects (IC??) at a range of 0.0073-0.14 ?M. Direct tubulin depolymerization assay in vitro was also performed. Results showed that that the two compounds can inhibit microtubule polymerization. Experimental measurements were also supported by molecular dynamic simulations, which showed that the two active compounds formed interactions with the colchicine-binding site of the tubulin protein. Our results helped us understand the nature of tubulin binding and determine the core design of a new series of potent inhibitors of tubulin polymerization. PMID:23786349

Ma, Yaqiong; Fang, Senbiao; Li, Huanhuan; Han, Chao; Lu, Yan; Zhao, Yonglong; Liu, Yingqian; Zhao, Chunyan

2013-07-01

227

Air entrainment by viscous contact lines  

NASA Astrophysics Data System (ADS)

We study the entrainment of air by moving contact lines, by plunging a solid plate into a reservoir of silicone oil. Above a critical plunging velocity we observe the formation of an air film, typically of 10 microns thickness, which subsequently destabilizes to form bubbles. The breakup of the air film occurs through the nucleation of ``rewetting'' holes, growing regions of liquid reestablishing contact with the surface -- the inverse process of the classical dewetting holes. Typical speeds for air entrainment turn out to be orders of magnitude larger than the speed for liquid film deposition. By varying the viscosity of the silicone oil, it is found that this critical speed depends on properties of both the liquid and the air. We propose an approximate hydrodynamic model that accounts for this two-phase nature of air entrainment.

Chan, Tak Shing; Marchand, Antonin; Andreotti, Bruno; Snoeijer, Jacco H.

2011-11-01

228

Dynamics of Solid Dispersions in Oil During the Lubrication of Point Contacts, Part I—Graphite  

Microsoft Academic Search

A Hertzian contact is lubricated with dispersed graphite in mineral oils under boundary lubrication conditions. The contacts are optically observed under pure rolling, combined rolling and sliding, and pure sliding conditions. The contact is formed with a steel ball on the flat surface of a glass disk. Photomicrographs are presented which show the distribution of the graphite in and around

C. Cusano; H. E. Sliney

1982-01-01

229

Evaporation dynamics of sessile liquid drops in still air with constant contact radius  

Microsoft Academic Search

Evaporation of sessile drops with constant wetting radius is investigated. In contrast to constant contact angle the temporal evaluation of the droplet volume can not be formulated in a closed form. We provide two approximations for initial contact angles below 90° which allow predicting the evaporation dynamics in practice easily. The derived linear approximation is suitable for small initial contact

Friedhelm Schönfeld; Karl-Heinz Graf; Steffen Hardt; Hans-Jürgen Butt

2008-01-01

230

Deterministic solutions and thermal analysis for mixed lubrication in point contacts  

Microsoft Academic Search

A deterministic numerical model has been developed for simulation of mixed lubrication in point contacts. The nominal contact area between rough surfaces can be divided into two parts: the regions for hydrodynamic lubrication and asperity contacts (boundary lubrication). In the area where the film thickness approaches zero the Reynolds equation can be modified into a reduced form and the normal

Wen-zhong Wang; Yuan-zhong Hu; Yu-chuan Liu; Hui Wang

2007-01-01

231

Effects of surface defects on rolling contact fatigue of rail  

Microsoft Academic Search

Rolling contact fatigue damages on the surface of rail such as head check, squats are one of growing problems. Squats are originated from the white etching layer (WEL) or the dent on rail surface and accompanied with dark spots including cracks. Another form of rail surface damage, known as “Ballast imprint” has become apparent. This form of damage is associated

Jungwon Seo; Seokjin Kwon; Deonghyeong Lee

2011-01-01

232

Quaternionic contact Einstein structures and the quaternionic contact Yamabe problem  

Microsoft Academic Search

A partial solution of the quaternionic contact Yamabe problem on the quaternionic sphere is given. It is shown that the torsion of the Biquard connection vanishes exactly when the trace-free part of the horizontal Ricci tensor of the Biquard connection is zero and this occurs precisely on 3-Sasakian manifolods. All conformal deformations sending the standard flat torsion-free quaternionic contact structure

Stefan Ivanov; Ivan Minchev; Dimiter Vassilev

2006-01-01

233

UltraForm finishing  

NASA Astrophysics Data System (ADS)

A new compliant sub-aperture optical finishing technique is being investigated for the removal of mid-spatial frequency artifacts and smoothing of hard polycrystalline infrared ceramics for aspheric applications and conformal shaped optics. The UltraForm concept was developed by OptiPro Systems, Ontario, NY, and is a joint process development effort with the Center for Optics manufacturing (COM). The UltraForm tool is a pressurized, elastomeric bladder in the shape of a toroid. Finishing pads are attached to the periphery, allowing the use of a wide variety of pad materials and abrasive selections. Experimentation has been conducted using both slurry mixes and fixed abrasive pads. The toroidal tool is rotated while the compliant tool is compressed into contact with the surface. Currently this process has specific interest for the finishing of conformal ALON Domes. Also to be discussed will be new versions of the UltraForm Tools which are currently be developed and tested.

Fess, E.; Schoen, J.; Bechtold, M.; Mohring, D.

2005-05-01

234

Crystal structure of scytalidoglutamic peptidase with its first potent inhibitor provides insights into substrate specificity and catalysis.  

PubMed

Scytalidoglutamic peptidase (SGP) from Scytalidium lignicolum is the founding member of the newly discovered\\ family of peptidases, G1, so far found exclusively in fungi. The crystal structure of SGP revealed a previously undescribed fold for peptidases and a unique catalytic dyad of residues Gln53 and Glu136. Surprisingly, the beta-sandwich structure of SGP is strikingly similar to members of the carbohydrate-binding concanavalin A-like lectins/glucanases superfamily. By analogy with the active sites of aspartic peptidases, a mechanism employing nucleophillic attack by a water molecule activated by the general base functionality of Glu136 has been proposed. Here, we report the first crystal structures of SGP in complex with two transition state peptide analogs designed to mimic the tetrahedral intermediate of the proteolytic reaction. Of these two analogs, the one containing a central S-hydroxyl group is a potent sub-nanomolar inhibitor of SGP. The inhibitor binds non-covalently to the concave surface of the upper beta-sheet and enables delineation of the S4 to S3' substrate specificity pockets of the enzyme. Structural differences in these pockets account for the unique substrate preferences of SGP among peptidases having an acidic pH optimum. Inhibitor binding is accompanied by a structuring of the region comprising residues Tyr71-Gly80 from being mostly disordered in the apoenzyme and leading to positioning of crucial active site residues for establishing enzyme-inhibitor contacts. In addition, conformational rearrangements are seen in a disulfide bridged surface loop (Cys141-Cys148), which moves inwards, partially closing the open substrate binding cleft of the native enzyme. The non-hydrolysable scissile bond analog of the inhibitor is located in the active site forming close contacts with Gln53 and Glu136. The nucleophilic water molecule is displaced and a unique mode of binding is observed with the S-OH of the inhibitor occupying the oxyanion binding site of the proposed tetrahedral intermediate. Details of the enzyme-inhibitor interactions and mechanistic interpretations are discussed. PMID:17069854

Pillai, B; Cherney, Maia M; Hiraga, Kazumi; Takada, Katsumi; Oda, Kohei; James, Michael N G

2006-09-27

235

Fabrication of optically reflecting ohmic contacts for semiconductor devices  

DOEpatents

A method is provided to produce a low-resistivity ohmic contact having high optical reflectivity on one side of a semiconductor device. The contact is formed by coating the semiconductor substrate with a thin metal film on the back reflecting side and then optically processing the wafer by illuminating it with electromagnetic radiation of a predetermined wavelength and energy level through the front side of the wafer for a predetermined period of time. This method produces a thin epitaxial alloy layer between the semiconductor substrate and the metal layer when a crystalline substrate is used. The alloy layer provides both a low-resistivity ohmic contact and high optical reflectance.

Sopori, Bhushan L. (Denver, CO)

1995-01-01

236

Direct measurement of friction of a fluctuating contact line.  

PubMed

We report a direct measurement of the friction coefficient of a fluctuating (and slipping) contact line using a thin vertical glass fiber of diameter d with one end glued onto a cantilever beam and the other end touching a liquid-air interface. By measuring the broadening of the resonant peak of the cantilever system with varying liquid viscosity ?, we find the friction coefficient of the contact line has a universal form, ?(c)?0.8?d?, independent of the liquid-solid contact angle. The obtained scaling law is further supported by the numerical simulation based on the phase field model under the generalized Navier boundary conditions. PMID:23889421

Guo, Shuo; Gao, Min; Xiong, Xiaomin; Wang, Yong Jian; Wang, Xiaoping; Sheng, Ping; Tong, Penger

2013-07-10

237

Fabrication of optically reflecting ohmic contacts for semiconductor devices  

DOEpatents

A method is provided to produce a low-resistivity ohmic contact having high optical reflectivity on one side of a semiconductor device. The contact is formed by coating the semiconductor substrate with a thin metal film on the back reflecting side and then optically processing the wafer by illuminating it with electromagnetic radiation of a predetermined wavelength and energy level through the front side of the wafer for a predetermined period of time. This method produces a thin epitaxial alloy layer between the semiconductor substrate and the metal layer when a crystalline substrate is used. The alloy layer provides both a low-resistivity ohmic contact and high optical reflectance. 5 figs.

Sopori, B.L.

1995-07-04

238

The Analgesic Activity of Bestatin as a Potent APN Inhibitor  

PubMed Central

Bestatin, a small molecular weight dipeptide, is a potent inhibitor of various aminopeptidases as well as LTA4 hydrolase. Various physiological functions of Bestatin have been identified, viz.: (1) an immunomodifier for enhancing the proliferation of normal human bone marrow granulocyte–macrophage progenitor cells to form CFU-GM colonies; Bestatin exerts a direct stimulating effect on lymphocytes via its fixation on the cell surface and an indirect effect on monocytes via aminopeptidase B inhibition of tuftsin catabolism; (2) an immunorestorator and curative or preventive agent for spontaneous tumor; Bestatin alone or its combination with chemicals can prolongate the disease-free interval and survival period in adult acute or chronic leukemia, therefore, it was primarily marketed in 1987 in Japan as an anticancer drug and servers as the only marketed inhibitor of Aminopeptidase N (APN/CD13) to cure leukemia to date; (3) a pan-hematopoietic stimulator and restorator; Bestatin promotes granulocytopoiesis and thrombocytopoiesis in vitro and restores them in myelo-hypoplastic men; (4) an inhibitor of several natural opioid peptides. Based on the knowledge that APN can cleave several bioactive neuropeptides such as Met-enkaphalins, Leu-enkaphalins, ?-Endorphin, and so on, the anti-aminopeptidase action of Bestatin also allows it to protect endopeptides against their catabolism, exhibiting analgesic activity. Although many scientific studies and great accomplishments have been achieved in this field, a large amount of problems are unsolved. This article reviews the promising results obtained for future development of the analgesic activity of Bestatin that can be of vital interest in a number of severe and chronic pain syndromes.

Jia, Mei-Rong; Wei, Tao; Xu, Wen-Fang

2010-01-01

239

A Highly Stable Al-Si Contact to Mo-Silicided Shallow Junctions  

NASA Astrophysics Data System (ADS)

Highly stable (up to 550°C) contacts have been realized in an Al-2%Si contact to n+-p and p+-n shallow junctions (Xj˜0.16 ?m) covered by a 0.1 ?m thick uniform MoSi2 layer, which was formed by the ion implantation through metal ITM technique. Low contact resistance was maintained, at submicron (0.5 ?m square) Al-Si/MoSi2 contacts, after 550°C sintering for 30 minutes.

Nagasawa, Eiji; Okabayashi, Hidekazu; Iida, Yasuo

1987-03-01

240

Aurelia aurita (Cnidaria) Oocytes' Contact Plate Structure and Development  

PubMed Central

One of the A. aurita medusa main mesoglea polypeptides, mesoglein, has been described previously. Mesoglein belongs to ZP-domain protein family and therefore we focused on A.aurita oogenesis. Antibodies against mesoglein (AB RA47) stain the plate in the place where germinal epithelium contacts oocyte on the paraffin sections. According to its position, we named the structure found the “contact plate”. Our main instrument was AB against mesoglein. ZP-domain occupies about half of the whole amino acid sequence of the mesoglein. Immunoblot after SDS-PAGE and AU-PAGE reveals two charged and high Mr bands among the female gonad germinal epithelium polypeptides. One of the gonads' polypeptides Mr corresponds to that of mesogleal cells, the other ones' Mr is higher. The morphological description of contact plate formation is the subject of the current work. Two types of AB RA47 positive granules were observed during progressive oogenesis stages. Granules form the contact plate in mature oocyte. Contact plate of A.aurita oocyte marks its animal pole and resembles Zona Pellucida by the following features: (1) it attracts spermatozoids; (2) the material of the contact plate is synthesized by oocyte and stored in granules; (3) these granules and the contact plate itself contain ZP domain protein(s); (4) contact plate is an extracellular structure made up of fiber bundles similar to those of conventional Zona Pellucida.

Adonin, Leonid S.; Shaposhnikova, Tatyana G.; Podgornaya, Olga

2012-01-01

241

Contact effects in light activated GaAs switches  

NASA Astrophysics Data System (ADS)

The purpose of this work was to examine the effects of various types of contacts on the switching behavior of a light-triggered power switch. The switch was constructed from a homogeneous wafer of chromium-doped gallium arsenide; the contacts were either ohmic, non-ohmic, or Schottky barriers. These were formed on the wafer in two geometries; both contacts on one side, and one contact spacings were used to permit the effects of the location of the existing laser pulse to be studied. A high voltage power supply (zero to 20 kV) was employed as the bias supply. A Nd:YAG laser, in the pulsed mode, was used to trigger the switch, which was mounted on a cold finger cooled to near liquid nitrogen temperature. Cooling reduced the dark current to manageable values (less than 1 micro A), and also reduced the avalanche breakdown voltage. The results of the measurements indicate that ohmic contacts produced more reliable switching than the non-ohmic or Schottky contacts, in as much as the shape of the output current pulse was better, and the number of pulses which the switches could sustain before the pulse shape deteriorated was greater, for the ohmic contacts. Surface discharge between the one-sided contacts obscured any differences in switching characteristics which might have depended on the location of the pulsed light excitation, so that no correlation between position and behavior could be obtained.

Durkin, P. S.

1985-05-01

242

Model of contact transitioning with \\  

Microsoft Academic Search

Arcing transition of metal-to-metal contacts is a key technical challenge in the development of railgun launchers. Theoretical understanding of the process remains poor and controversial. Several authors have explained transitioning by a velocity skin effect driven \\

John P. Barber; Yuri A. Dreizin

1995-01-01

243

NCI: SBIR & STTR - Contact Us  

Cancer.gov

Skip Navigation Sign Up for Updates | Follow us on Twitter | Connect with us on LinkedIn | Contact Us | Site Map Search About Program Information Program Structure Goals Eligibility Criteria Employment Opportunities Meet the Team Funding Opportunities Find

244

Contact Printing with Nanoscale Resolution  

NASA Astrophysics Data System (ADS)

We have developed an additive contact printing technique that offers nanometer length scale resolution. This printing technique, which we refer to as nanotransfer printing (nTP), relies on tailored interfacial chemistries for transferring thin layers of functional materials from the raised regions of a stamp onto a substrate. Pattern transfer occurs at ambient conditions, with contact times <15 seconds. To illustrate the versatility of nTP, we have fabricated gold contacts and interconnects for functional devices and simple circuits, such as high-performance organic transistors and inverter circuits, as well as metal-insulator-metal capacitors, on plastic substrates. More recently, we have printed mechanically-robust and reliable electrical contacts for organic molecular layers using nTP.

Loo, Yueh-Lin; Rogers, John A.; Hsu, Julia W. P.; Willett, R. L.

2003-03-01

245

Focusing on Contact Lens Safety  

MedlinePLUS

... regulates contact lenses—including those intended for vision correction and for decorative purposes—as prescription devices, and ... ability to focus. It's primarily used for the correction of nearsightedness. The most common type is overnight ...

246

Contact Reductions, Mechanics and Duality.  

National Technical Information Service (NTIS)

Contact reduction is very closely related to symplectic reduction, but it allows symmetries that are not manifest in Hamiltonian mechanics and moreover, solution of the reduced problems yields solution of the original problem without further integration.

P. Severa

1999-01-01

247

Contact Printing with Coherent Light.  

National Technical Information Service (NTIS)

Investigation of coherent light printing included the consideration of both beam swinging and fixed illumination systems, and the latter was chosen for use on the modified Kodak Concord continuous contact printer. A technique was adopted whereby a cylindr...

E. L. Bouche D. A. Servaes

1967-01-01

248

Contact Lens Use in Industry  

MedlinePLUS

... for updates. FS96 7/10 © 2010 Prevent Blindness America ® All rights reserved. According to the Contact Lens ... Occupational Safety and Health (NIOSH). Recommendations Prevent Blindness America makes the following recommendations to management that directs ...

249

Human placenta is a potent hematopoietic niche containing hematopoietic stem and progenitor cells throughout development  

PubMed Central

Hematopoietic stem cells (HSC) are responsible for the life-long production of the blood system and are pivotal cells in hematologic transplantation therapies. During mouse and human development, the first HSCs are produced in the aorta-gonad-mesonephros region. Subsequent to this emergence, HSCs are found in other anatomical sites of the mouse conceptus. While the mouse placenta contains abundant HSCs at midgestation, little is known concerning whether HSCs or hematopoietic progenitors are present and supported in the human placenta during development. In this study we show, over a range of developmental times including term, that the human placenta contains hematopoietic progenitors and HSCs. Moreover, stromal cell lines generated from human placenta at several developmental time points are pericyte-like cells and support human hematopoiesis. Immunostaining of placenta sections during development localizes hematopoietic cells in close contact with pericytes/perivascular cells. Thus, the human placenta is a potent hematopoietic niche throughout development.

Robin, Catherine; Bollerot, Karine; Mendes, Sandra; Haak, Esther; Crisan, Mihaela; Cerisoli, Francesco; Lauw, Ivoune; Kaimakis, Polynikis; Jorna, Ruud; Vermeulen, Mark; Kayser, Manfred; van der Linden, Reinier; Imanirad, Parisa; Verstegen, Monique; Nawaz-Yousaf, Humaira; Papazian, Natalie; Steegers, Eric; Cupedo, Tom; Dzierzak, Elaine

2009-01-01

250

Discovery of highly selective and potent p38 inhibitors based on a phthalazine scaffold.  

PubMed

Investigations into the structure-activity relationships (SAR) of a series of phthalazine-based inhibitors of p38 are described. These efforts originated from quinazoline 1 and through rational design led to the development of a series of orally bioavailable, potent, and selective inhibitors. Kinase selectivity was achieved by exploiting a collection of interactions with p38alpha including close contact to Ala157, occupation of the hydrophobic gatekeeper pocket, and a residue flip with Gly110. Substitutions on the phthalazine influenced the pharmacokinetic properties, of which compound 16 displayed the most desirable profile. Oral dosing (0.03 mg/kg) of 16 in rats 1 h prior to LPS challenge gave a >50% decrease in TNFalpha production. PMID:18817365

Herberich, Brad; Cao, Guo-Qiang; Chakrabarti, Partha P; Falsey, James R; Pettus, Liping; Rzasa, Robert M; Reed, Anthony B; Reichelt, Andreas; Sham, Kelvin; Thaman, Maya; Wurz, Ryan P; Xu, Shimin; Zhang, Dawei; Hsieh, Faye; Lee, Matthew R; Syed, Rashid; Li, Vivian; Grosfeld, David; Plant, Matthew H; Henkle, Bradley; Sherman, Lisa; Middleton, Scot; Wong, Lu Min; Tasker, Andrew S

2008-09-26

251

Method for lubricating contacting surfaces  

SciTech Connect

A method is provided for tribological lubrication of sliding contact surfaces, where two surfaces are in contact and in motion relative to each other, operating in a vapor-phase environment containing at least one alcohol compound at a concentration sufficiently high to provide one monolayer of coverage on at least one of the surfaces, where the alcohol compound continuously reacts at the surface to provide lubrication.

Dugger, Michael T. (Tijeras, NM); Ohlhausen, James A. (Albuquerque, NM); Asay, David B. (Boalsburg, PA); Kim, Seong H. (State College, PA)

2011-12-06

252

Contact dermatitis from textile dyes.  

PubMed

6 female patients with allergic contact dermatitis from textile dyes are described. Lesions were confined to areas in direct contact with the offending garment, mainly where friction and/or pressure occurred. Patch tests were positive to 2 or more disperse dyes. Thin-layer chromatography was carried out on the dyes extracted from fabrics of 3 patients, for the identification of textile dyes. PMID:7924308

Lisboa, C; Barros, M A; Azenha, A

1994-07-01

253

Continuum models for the contact line problem  

NASA Astrophysics Data System (ADS)

Continuum models are derived for the moving contact line problem through a combination of macroscopic and microscopic considerations. Macroscopic thermodynamic argument is used to place constraints on the form of the boundary conditions at the solid surface and the contact line. This information is then used to set up molecular dynamics to measure the detailed functional dependence of the boundary conditions. Long range molecular forces are taken into account in the form of a surface potential. This allows us to handle the case of complete wetting as well as the case of partial wetting. In particular, we obtain a new continuum model for both cases in a unified form. Two main parameters and different spreading regimes are identified from the analysis of the energy dissipations for the continuum model. Scaling laws in these different regimes are derived. The new continuum model also allows us to derive boundary conditions for the lubrication approximation. Numerical results are presented for the thin film model and the effect of the boundary condition is investigated.

Ren, Weiqing; Hu, Dan; E, Weinan

2010-10-01

254

Permission Forms  

ERIC Educational Resources Information Center

The prevailing practice in public schools is to routinely require permission or release forms for field trips and other activities that pose potential for liability. The legal status of such forms varies, but they are generally considered to be neither rock-solid protection nor legally valueless in terms of immunity. The following case and the…

Zirkel, Perry A.

2005-01-01

255

Diabetes and contact lens wear.  

PubMed

The literature suggests that diabetic patients may have altered tear chemistry and tear secretion as well as structural and functional changes to the corneal epithelium, endothelium and nerves. These factors, together with a reported increased incidence of corneal infection, suggest that diabetic patients may be particularly susceptible to developing ocular complications during contact lens wear. Reports of contact lens-induced complications in diabetic patients do exist, although a number of these reports concern patients with advanced diabetic eye disease using lenses on an extended wear basis. Over the past decade or so, there have been published studies documenting the response of the diabetic eye to more modern contact lens modalities. The results of these studies suggest that contact lenses can be a viable mode of refractive correction for diabetic patients. Furthermore, new research suggests that the measurement of tear glucose concentration could, in future, be used to monitor metabolic control non-invasively in diabetic patients. This could be carried out using contact lenses manufactured from hydrogel polymers embedded with glucose-sensing agents or nanoscale digital electronic technology. The purpose of this paper is to review the literature on the anterior ocular manifestations of diabetes, particularly that pertaining to contact lens wear. PMID:22537249

O'Donnell, Clare; Efron, Nathan

2012-04-27

256

The Kinematics of Contact and Grasp  

Microsoft Academic Search

The kinematics of contact describe the motion of a point of contact over the surfaces of two contacting objects in response to a relative motion of these objects. Using concepts from differential geometry, I derive a set of equations, called the contact equations, that embody this relationship. I employ the contact equations to design the following applications to be executed

David J. Montana

1988-01-01

257

Role of Perceived Importance in Intergroup Contact  

Microsoft Academic Search

Furthering G. W. Allport's (1954) contentions for optimal contact, the authors introduce a new construct: the perceived importance of contact. They propose that perceived importance is the best proximal predictor of contact's reduction of prejudice. If individuals have opportunities for contact at work or in the neighborhood, their chances to have intergroup acquaintances and friends increase. Intergroup contact among acquaintances

Rolf van Dick; Ulrich Wagner; Thomas F. Pettigrew; Oliver Christ; Carina Wolf; Thomas Petzel; Vanessa Smith Castro; James S. Jackson

2004-01-01

258

Lateral contact of slender prismatic bodies  

Microsoft Academic Search

Many nominally two-dimensional contact problems, such as the contact of parallel rollers or spur gears, exhibit slow axial variation in contact conditions due to man- ufacturing errors, misalignment or generalized beam deflections of the contacting bodies. In this paper, an asymptotic method is used to develop a solution to such problems, the inner problem being the two-dimensional Hertzian contact theory

J. R. Barber

1997-01-01

259

Partial slip in mesoscale contacts: Dependence on contact size  

NASA Astrophysics Data System (ADS)

Using acoustic resonators, we have studied the occurrence and the magnitude of partial slip between glass spheres and polymer surfaces. The measurement relies on the shifts of resonance frequency and bandwidth, ?f and ??, induced by the contact as well as the dependence of ?f and ?? on the amplitude of oscillation. One often finds a decrease of ?f at elevated amplitudes, which goes back to partial slip (also “microslip”). Building on two different models of partial slip, we derive the frequency-amplitude relation from the force-displacement relation. In accordance with both models, the bandwidth is found to increase with amplitude in the partial slip regime. For the highest amplitudes and largest spheres investigated, one observes a decrease of bandwidth with amplitude, which is interpreted as a transition to gross slip. Deviating from both models of partial slip, ?f is sometimes found to be independent of amplitude in the low-amplitude range. Constant ?f implies linear force-displacement relations. The critical amplitude for the onset of partial slip depends on the contact radius, where partial slip is more pronounced for larger contacts. This finding can be explained by a smooth stress profile at the edge of the contact with no singularity. The stress at the edge might be lowered by nanoscale roughness, by capillary forces, or by the inability of the two surfaces to reestablish a sticking contact at the turning point of the oscillation.

Hanke, Sylvia; Petri, Judith; Johannsmann, Diethelm

2013-09-01

260

Laser Forming of Aerospace Alloys  

Microsoft Academic Search

Non-contact forming by application of a thermal source has been known for some time. Recently, it has been shown that much greater controllability can be introduced by replacing the thermal source with a laser. This yields a process with strong potential for application in aerospace, including the rapid manufacture of prototypes and the adjustment of misaligned components. This paper briefly

K. G. Watkins; S. P. Edwardson; J. Magee; G. Dearden; R. L. Cooke; J. Sidhu; N. J. Calder

261

Cucurbitacins-type triterpene with potent activity on mouse embryonic fibroblast from Cucumis prophetarum, cucurbitaceae  

PubMed Central

Background: Higher plants are considered as a well-known source of the potent anticancer metabolites with diversity of chemical structures. For instance, taxol is an amazing diterpene alkaloid had been lunched since 1990. Objective: To isolate the major compounds from the fruit extract of Cucumis prophetarum, Cucurbitaceae, which are mainly responsible for the bioactivities as anticancer. Materials and Methods: Plant material was shady air dried, extracted with equal volume of chloroform/methanol, and fractionated with different adsorbents. The structures of obtained pure compounds were elucidated with different spectroscopic techniques employing 1D (1H and 13C) and 2D (COSY, HMQC and HMBC) NMR (Nuclear Magnetic Resonance Spectrometry) and ESI-MS (Eelectrospray Ionization Mass Spectrometry) spectroscopy. The pure isolates were tested towards human cancer cell lines, mouse embryonic fibroblast (NIH3T3) and virally transformed form (KA3IT). Results: Two cucurbitacins derivatives, dihydocucurbitacin B (1) and cucurbitacin B (2), had been obtained. Compounds 1 and 2 showed (showed potent inhibitory activities toward NIH3T3 and KA31T with IC50 0.2, 0.15, 2.5 and 2.0 ?g/ml, respectively. Conclusion: The naturally cucurbitacin derivatives (dihydocucurbitacin B and cucurbitacin B) showed potent activities towards NIH3T3 and KA31T, could be considered as a lead of discovering a new anticancer natural drug.

Ayyad, Seif-Eldin N.; Abdel-Lateff, Ahmed; Basaif, Salim A.; Shier, Thomas

2011-01-01

262

Dimeric 2G12 as a Potent Protection against HIV-1  

PubMed Central

We previously showed that broadly neutralizing anti-HIV-1 antibody 2G12 (human IgG1) naturally forms dimers that are more potent than monomeric 2G12 in in vitro neutralization of various strains of HIV-1. In this study, we have investigated the protective effects of monomeric versus dimeric 2G12 against HIV-1 infection in vivo using a humanized mouse model. Our results showed that passively transferred, purified 2G12 dimer is more potent than 2G12 monomer at preventing CD4 T cell loss and suppressing the increase of viral load following HIV-1 infection of humanized mice. Using humanized mice bearing IgG “backpack” tumors that provided 2G12 antibodies continuously, we found that a sustained dimer concentration of 5–25 µg/ml during the course of infection provides effective protection against HIV-1. Importantly, 2G12 dimer at this concentration does not favor mutations of the HIV-1 envelope that would cause the virus to completely escape 2G12 neutralization. We have therefore identified dimeric 2G12 as a potent prophylactic reagent against HIV-1 in vivo, which could be used as part of an antibody cocktail to prevent HIV-1 infection.

Luo, Xin M.; Lei, Margarida Y. Y.; Feidi, Rana A.; West, Anthony P.; Balazs, Alejandro Benjamin; Bjorkman, Pamela J.; Yang, Lili; Baltimore, David

2010-01-01

263

The nature of electrical interaction of Schottky contacts  

SciTech Connect

Electrical interaction between metal-semiconductor contacts combined in a diode matrix with a Schottky barrier manifests itself in an appreciable variation in their surface potentials and static current-volt-characteristics. The necessary condition for appearance of electrical interaction between such contacts consists in the presence of a peripheral electric field (a halo) around them; this field propagates to a fairly large distances (<30 {mu}m). The sufficient condition is the presence of regions where the above halos overlap. It has been shown that variation in the surface potential and the current-voltage characteristics of contacts occurs under the effect of the intrinsic electric field of the contact's periphery and also under the effect of an electric field at matrix periphery; the latter field is formed as a result of superposition of electric fields of halos which form its contacts. The degree of the corresponding effect is governed by the distance between contacts and by the total charge of the space charge regions for all contacts of the matrix: their number, sizes (diameter D{sub i,j}), concentration of doping impurities in the semiconductor N{sub D}, and physical nature of a metal-semiconductor system with a Schottky barrier (with the barrier height {phi}{sub b}). It is established that bringing the contacts closer leads to a relative decrease in the threshold value of the 'dead' zone in the forward current-voltage characteristics, an increase in the effective height of the barrier, and an insignificant increase in the nonideality factor. An increase in the total area of contacts (a total electric charge in the space charge region) in the matrix brings about an increase in the threshold value of the 'dead' zone, a relative decrease in the effective barrier height, and an insignificant increase in the ideality factor.

Torkhov, N. A., E-mail: trkf@mail.ru [Research Institute of Semiconductor Devices (Russian Federation)

2011-08-15

264

National Cancer Institute - CPFP Intranet - Forms  

Cancer.gov

Skip navigation. CPFP Intranet Responsibilities Advisory Board Outside Activities Manuscripts, Abstracts and Presentations Ethics and Ethical Issues Forms and Schedules Travel Training Reports General Information Employment Resources Home Page Contact

265

Dosage Form  

Center for Drug Evaluation (CDER)

... Concept ID: C42636. Version Number. 008. Description. This standard provides for all drug dosage forms. The granularity of ... More results from www.fda.gov/drugs/developmentapprovalprocess/formssubmissionrequirements

266

[Toxic contact dermatitis from poison ivy in a private garden in Germany].  

PubMed

A couple suffered for 5 years from recurrent eruptions with vesicles and bullae after contact with an unknown "climbing weed" in their private garden in Germany. After this plant was identified as poison ivy and eradicated, their skin problems were solved. This is the first report of poison ivy in this setting. Urushiols in poison ivy are not only strong allergens but also potent irritants. Negative patch tests in the husband suggest that the bullous dermatitis was a toxic reaction. PMID:15834598

Schauder, S; Callauch, R; Hausen, B M

2006-07-01

267

SOPP 8103: Headquarters Contacts With Regulated ...  

Center for Biologics Evaluation and Research (CBER)

... When contacted by representatives of a manufacturer of ... should be advised to contact the Director ... ORA or CBER investigator(s). Contacts should be ... More results from www.fda.gov/biologicsbloodvaccines/guidancecomplianceregulatoryinformation/proceduressopps

268

Method and apparatus for high-efficiency direct contact condensation  

DOEpatents

A direct contact condenser having a downward vapor flow chamber and an upward vapor flow chamber, wherein each of the vapor flow chambers includes a plurality of cooling liquid supplying pipes and a vapor-liquid contact medium disposed thereunder to facilitate contact and direct heat exchange between the vapor and cooling liquid. The contact medium includes a plurality of sheets arranged to form vertical interleaved channels or passageways for the vapor and cooling liquid streams. The upward vapor flow chamber also includes a second set of cooling liquid supplying pipes disposed beneath the vapor-liquid contact medium which operate intermittently in response to a pressure differential within the upward vapor flow chamber. The condenser further includes separate wells for collecting condensate and cooling liquid from each of the vapor flow chambers. In alternate embodiments, the condenser includes a cross-current flow chamber and an upward flow chamber, a plurality of upward flow chambers, or a single upward flow chamber. The method of use of the direct contact condenser of this invention includes passing a vapor stream sequentially through the downward and upward vapor flow chambers, where the vapor is condensed as a result of heat exchange with the cooling liquid in the contact medium. The concentration of noncondensable gases in the resulting condensate-liquid mixtures can be minimized by controlling the partial pressure of the vapor, which depends in part upon the geometry of the vapor-liquid contact medium. In another aspect of this invention, the physical and chemical performance of a direct contact condenser can be predicted based on the vapor and coolant compositions, the condensation conditions. and the geometric properties of the contact medium.

Bharathan, Desikan (Lakewood, CO); Parent, Yves (Golden, CO); Hassani, A. Vahab (Golden, CO)

1999-01-01

269

"Contact" of nanoscale stiff films.  

PubMed

We investigated the contact behaviors of a nanoscopic stiff thin film bonded to a compliant substrate and derived an analytical solution for determining the elastic modulus of thin films. Microscopic contact deformations of the gold and polydopamine thin films (<200 nm) coated on polydimethylsiloxane elastomers were measured by indenting a soft tip and analyzed in the framework of the classical plate theory and Johnson-Kendall-Roberts (JKR) contact mechanics. The analysis of this thin film contact mechanics focused on the bending and stretching resistance of thin films and is fundamentally different from conventional indentation measurements where the focus is on the fracture and compression of the films. The analytical solution of the elastic modulus of nanoscopic thin films was validated experimentally using 50 and 100 nm gold thin films coated on polydimethylsiloxane elastomers. The technical application of this analysis was further demonstrated by measuring the elastic modulus of thin films of polydopamine, a recently discovered biomimetic universal coating material. Furthermore, the method presented here is able to quantify the contact behaviors of nanoscopic thin films, effectively providing fundamental design parameters, the elastic modulus, and the work of adhesion, crucial for transferring them effectively into practical applications. PMID:22616836

Yang, Fut K; Zhang, Wei; Han, Yougun; Yoffe, Serge; Cho, Yungchi; Zhao, Boxin

2012-05-31

270

Pharmacokinetics of heptacaine, a novel potent local anaesthetic agent, after rectal administration to rats.  

PubMed

The pharmacokinetics of heptacaine, N-(2-(2-heptyloxyphenylcarbamoyloxy)ethyl)-piperidinium chloride, a new long-acting potent carbanilate type local anaesthetic, proposed for local anaesthesia in complex treatment of hemorrhoids, was studied following its rectal administration to rats in the form of cocoa butter suppositories. The heptacaine plasma concentration, 0.0083% of dose/ml, peaked at 90 min post administration and the maximum rate of its bioavailability, 0.19% of dose/min, assessed by deconvolution, occurred 38 min post administration. The plasma elimination half-life of heptacaine was 133 min and its biological availability of 52% was comparable to other agents of the class. PMID:1490492

Faberová, V; Durisová, M; Trnovec, T; Divisová, D

271

Chroman and tetrahydroquinoline ureas as potent TRPV1 antagonists.  

PubMed

Novel chroman and tetrahydroquinoline ureas were synthesized and evaluated for their activity as TRPV1 antagonists. It was found that aryl substituents on the 7- or 8-position of both bicyclic scaffolds imparted the best in vitro potency at TRPV1. The most potent chroman ureas were assessed in chronic and acute pain models, and compounds with the ability to cross the blood-brain barrier were shown to be highly efficacious. The tetrahydroquinoline ureas were found to be potent CYP3A4 inhibitors, but replacement of bulky substituents at the nitrogen atom of the tetrahydroisoquinoline moiety with small groups such as methyl can minimize the inhibition. PMID:21315587

Schmidt, Robert G; Bayburt, Erol K; Latshaw, Steven P; Koenig, John R; Daanen, Jerome F; McDonald, Heath A; Bianchi, Bruce R; Zhong, Chengmin; Joshi, Shailen; Honore, Prisca; Marsh, Kennan C; Lee, Chih-Hung; Faltynek, Connie R; Gomtsyan, Arthur

2011-01-21

272

Regulatory Submissions - Part V: Food Contact Substance ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... Regulatory Submissions - Part V: Food Contact Substance Submissions. ... A. General Information about Food Contact Notification Submissions. ... More results from www.fda.gov/food/guidanceregulation/guidancedocumentsregulatoryinformation

273

Regulatory Report: FDA's Food Contact Substance ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... Regulatory Report: FDA's Food Contact Substance Notification Program. Authors. ... Food Contact Substance Formulations. ... More results from www.fda.gov/food/ingredientspackaginglabeling/packagingfcs

274

Environmental Decision Memo for Food Contact Notification ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... polylactide polymers in contact with food. Notifier: Johnson Polymer LLC and Nature Works. To: Division of Food Contact ... More results from www.fda.gov/food/ingredientspackaginglabeling/environmentaldecisions

275

Contacts de langues et representations (Language Contacts and Representations).  

ERIC Educational Resources Information Center

|Essays on language contact and the image of language, entirely in French, include: "Representations 'du' contexte et representations 'en' contexte? Eleves et enseignants face a l'apprentissage de la langue" ("Representations 'of' Context or Representations 'in' Context? Students and Teachers Facing Language Learning" (Laurent Gajo); "Le…

Matthey, Marinette, Ed.

1997-01-01

276

Optofluidic realization and retaining of cell–cell contact using an abrupt tapered optical fibre  

NASA Astrophysics Data System (ADS)

Studies reveal that there exists much interaction and communication between bacterial cells, with parts of these social behaviors depending on cell-cell contacts. The cell-cell contact has proved to be crucial for determining various biochemical processes. However, for cell culture with relatively low cell concentration, it is difficult to precisely control and retain the contact of a small group of cells. Particularly, the retaining of cell-cell contact is difficult when flows occur in the medium. Here, we report an optofluidic method for realization and retaining of Escherichia coli cell-cell contact in a microfluidic channel using an abrupt tapered optical fibre. The contact process is based on launching a 980-nm wavelength laser into the fibre, E. coli cells were trapped onto the fibre tip one after another, retaining cell-cell contact and forming a highly organized cell chain. The formed chains further show the ability as bio-optical waveguides.

Xin, Hongbao; Zhang, Yao; Lei, Hongxiang; Li, Yayi; Zhang, Huixian; Li, Baojun

2013-06-01

277

Mechanisms of current flow in metal-semiconductor ohmic contacts  

SciTech Connect

Published data on the properties of metal-semiconductor ohmic contacts and mechanisms of current flow in these contacts (thermionic emission, field emission, thermal-field emission, and also current flow through metal shunts) are reviewed. Theoretical dependences of the resistance of an ohmic contact on temperature and the charge-carrier concentration in a semiconductor were compared with experimental data on ohmic contacts to II-VI semiconductors (ZnSe, ZnO), III-V semiconductors (GaN, AlN, InN, GaAs, GaP, InP), Group IV semiconductors (SiC, diamond), and alloys of these semiconductors. In ohmic contacts based on lightly doped semiconductors, the main mechanism of current flow is thermionic emission with the metal-semiconductor potential barrier height equal to 0.1-0.2 eV. In ohmic contacts based on heavily doped semiconductors, the current flow is effected owing to the field emission, while the metal-semiconductor potential barrier height is equal to 0.3-0.5 eV. In alloyed In contacts to GaP and GaN, a mechanism of current flow that is not characteristic of Schottky diodes (current flow through metal shunts formed by deposition of metal atoms onto dislocations or other imperfections in semiconductors) is observed.

Blank, T. V., E-mail: tblank@mail.ioffe.ru; Gol'dberg, Yu. A. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

2007-11-15

278

Allergic contact dermatitis and cosmetics.  

PubMed

Contact dermatitis is a common dermatologic condition that can result from exposure to allergens at home or at work. Cosmetics represent a large diverse group of products that Americans apply to their skin to treat disease or enhance beauty. With increased use of cosmetics, the rate of sensitization to many allergenic components has increased. We review the more common allergens present in cosmetics as well as the types of cosmetics that are known to contain them. With proper education and patch testing, dermatologists will be able to identify contact allergies to cosmetic ingredients and help patients avoid the offending products. PMID:23259208

Watkins, Shannon; Zippin, Jonathan

2012-10-01

279

[Tefillin-related contact dermatitis].  

PubMed

We describe a 14 year-old male with a background of atopic dermatitis who developed a contact dermatitis reaction on the left arm to the leather straps of tefillin (phylacteries), a religious article worn by observant Jewish men from the age 13 years during most morning prayer services. Patch testing revealed contact allergy to potassium dichromate, a chemical involved in leather tanning. Placing the leather straps over clothing and later switching to potassium dichromate-free leather straps resolved the condition. It is important to recognize this uncommon phenomena in a population in which a large proportion regularly use this religious article. PMID:22026052

Hashkes, Philip J; Sagi, Efraim

2011-09-01

280

Contact Geometry of Hyperbolic Equations of Generic Type  

NASA Astrophysics Data System (ADS)

We study the contact geometry of scalar second order hyperbolic equations in the plane of generic type. Following a derivation of parametrized contact-invariants to distinguish Monge-Ampère (class 6-6), Goursat (class 6-7) and generic (class 7-7) hyperbolic equations, we use Cartan's equivalence method to study the generic case. An intriguing feature of this class of equations is that every generic hyperbolic equation admits at most a nine-dimensional contact symmetry algebra. The nine-dimensional bound is sharp: normal forms for the contact-equivalence classes of these maximally symmetric generic hyperbolic equations are derived and explicit symmetry algebras are presented. Moreover, these maximally symmetric equations are Darboux integrable. An enumeration of several submaximally symmetric (eight and seven-dimensional) generic hyperbolic structures is also given.

The, Dennis

2008-08-01

281

Dynamical Coulomb blockade observed in nanosized electrical contacts.  

PubMed

Electrical contacts between nanoengineered systems are expected to constitute the basic building blocks of future nanoscale electronics. However, the accurate characterization and understanding of electrical contacts at the nanoscale is an experimentally challenging task. Here, we employ low-temperature scanning tunneling spectroscopy to investigate the conductance of individual nanocontacts formed between flat Pb islands and their supporting substrates. We observe a suppression of the differential tunnel conductance at small bias voltages due to dynamical Coulomb blockade effects. The differential conductance spectra allow us to determine the capacitances and resistances of the electrical contacts which depend systematically on the island-substrate contact area. Calculations based on the theory of environmentally assisted tunneling agree well with the measurements. PMID:22540609

Brun, Christophe; Müller, Konrad H; Hong, I-Po; Patthey, François; Flindt, Christian; Schneider, Wolf-Dieter

2012-03-21

282

Contact hole shrink process using directed self-assembly  

NASA Astrophysics Data System (ADS)

We report on a contact hole shrink process using directed self-assembly. A diblock copolymer, poly (styrene-blockmethyl methacrylate) (PS-b-PMMA), is used to shrink contact holes. Contact hole guide patterns for graphoepitaxy are formed by ArF photoresists. Cylindrical domains of PMMA is removed using organic solvents after DUV (? <200 nm) irradiation. In this work, it is found that a solvent system is the best developer from the evaluated single solvent systems and mixed solvent systems. The wet development of PS-b-PMMA strongly depends on total exposure dose of DUV irradiation. With lower exposure dose, the cylindrical domains of PMMA are not clearly removed. With optimum exposure dose, PMMA is developed clearly. The contact hole guide patterns of 75 nm in diameter are successfully shrunk to 20 nm in diameter using the wet development process.

Seino, Yuriko; Yonemitsu, Hiroki; Sato, Hironobu; Kanno, Masahiro; Kato, Hikazu; Kobayashi, Katsutoshi; Kawanishi, Ayako; Azuma, Tsukasa; Muramatsu, Makoto; Nagahara, Seiji; Kitano, Takahiro; Toshima, Takayuki

2012-03-01

283

Divalent Cation Ionophore A23187: A Potent Protein Synthesis Inhibitor.  

National Technical Information Service (NTIS)

The antibiotic drugs A23187 is a potent protein synthesis inhibitor at very low concentrations. This may be a direct effect on protein synthesis or may result from release of internal stores of divalent cations. In addition, the ionophore apparently incre...

J. de Vellis J. E. Bottenstein

1976-01-01

284

2,5-Disubstituted pyridines as potent GPR119 agonists.  

PubMed

A series of 2-piperazinyl-5-alkoxypyridines were synthesized and screened against human GPR119 receptor. Through SAR analysis, compounds containing 2-alkylsulfonylpiperazinyl-5-alkoxypyridines were discovered and found to be potent agonists of the human GPR119 receptor. PMID:20227877

Wu, Yulin; Kuntz, Judith D; Carpenter, Andrew J; Fang, Jing; Sauls, Howard R; Gomez, Daniel J; Ammala, Carina; Xu, Yun; Hart, Shane; Tadepalli, Sarva

2010-02-25

285

Potent Antioxidant Dendrimers Lacking Pro-oxidant Activity  

PubMed Central

It is well known that antioxidants have protective effects against oxidative stress. Unfortunately, in the presence of transition metals, antioxidants including polyphenols with potent antioxidant activities may also exhibit pro-oxidant effects, which may irreversibly damage DNA. Therefore, antioxidants with strong free radical scavenging abilities and devoid of pro-oxidant effects would be of immense biological importance. We report two antioxidant dendrimers with a surface rich in multiple phenolic hydroxyl groups, benzylic hydrogens and electron donating ring substituents that contribute to their potent free radical quenching property. In order to minimize their pro-oxidant effects, the dendrimers were designed with a metal chelating tris(2-aminoethyl)amine (TREN) core. The dendritic antioxidants were prepared by attachment of six syringaldehyde or vanillin molecules to TREN by reductive amination. They exhibited potent radical scavenging properties: 5 times stronger than quercetin and 15 times more potent than Trolox according to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The antioxidant dendrimers also protected low-density lipoprotein, lysozyme and DNA against 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced free radical damage. More importantly, unlike quercetin and Trolox, the two TREN antioxidant dendrimers did not damage DNA via their pro-oxidant effects when incubated with physiological amounts of copper ions. The dendrimers also showed no cytotoxicity towards Chinese hamster ovary cells.

Lee, Choon Young; Sharma, Ajit; Uzarski, Rebecca L.; Cheong, Jae Eun; Xu, Hao; Held, Rich A.; Upadhaya, Samik K.; Nelson, Julie L.

2010-01-01

286

Potent antioxidant dendrimers lacking pro-oxidant activity.  

PubMed

It is well known that antioxidants have protective effects against oxidative stress. Unfortunately, in the presence of transition metals, antioxidants, including polyphenols with potent antioxidant activities, may also exhibit pro-oxidant effects, which may irreversibly damage DNA. Therefore, antioxidants with strong free radical-scavenging abilities and devoid of pro-oxidant effects would be of immense biological importance. We report two antioxidant dendrimers with a surface rich in multiple phenolic hydroxyl groups, benzylic hydrogens, and electron-donating ring substituents that contribute to their potent free radical-quenching properties. To minimize their pro-oxidant effects, the dendrimers were designed with a metal-chelating tris(2-aminoethyl)amine (TREN) core. The dendritic antioxidants were prepared by attachment of six syringaldehyde or vanillin molecules to TREN by reductive amination. They exhibited potent radical-scavenging properties: 5 times stronger than quercetin and 15 times more potent than Trolox according to the 1,1-diphenyl-2-picrylhydrazyl assay. The antioxidant dendrimers also protected low-density lipoprotein, lysozyme, and DNA against 2,2'-azobis(2-amidinopropane) dihydrochloride-induced free radical damage. More importantly, unlike quercetin and Trolox, the two TREN antioxidant dendrimers did not damage DNA via their pro-oxidant effects when incubated with physiological amounts of copper ions. The dendrimers also showed no cytotoxicity toward Chinese hamster ovary cells. PMID:20977937

Lee, Choon Young; Sharma, Ajit; Uzarski, Rebecca L; Cheong, Jae Eun; Xu, Hao; Held, Rich A; Upadhaya, Samik K; Nelson, Julie L

2010-10-23

287

Potent antioxidant role of Pirfenidone in experimental cirrhosis  

Microsoft Academic Search

Three important features must be considered when proposing therapeutic strategies in liver cirrhosis: inflammation, oxidative stress and fibrogenesis. Pirfenidone is a synthetic molecule which oxidative action has not been tested in cirrhosis. Cirrhosis was induced in rats by ligation of the common bile duct or carbon tetrachloride (CCl4) chronic intoxication and treated with Pirfenidone or Diphenyleneiodonium (a potent known antioxidant)

Adriana Salazar-Montes; Luis Ruiz-Corro; Alberto López-Reyes; Eugenio Castrejón-Gómez; Juan Armendáriz-Borunda

2008-01-01

288

Potent pyrrolidine- and piperidine-based BACE-1 inhibitors  

SciTech Connect

Based on lead compound 1 identified from the patent literature, we developed novel patentable BACE-1 inhibitors by introducing a cyclic amine scaffold. Extensive SAR studies on both pyrrolidines and piperidines ultimately led to inhibitor 2f, one of the most potent inhibitors synthesized to date. The discovery and development of novel BACE-1 inhibitors incorporating a cyclic amine scaffold is described.

Iserloh, U.; Wu, Y.; Cumming, J.N.; Pan, J.; Wang, L.Y.; Stamford, A.W.; Kennedy, M.E.; Kuvelkar, R.; Chen, X.; Parker, E.M.; Strickland, C.; Voigt, J. (Schering-Plough)

2008-08-18

289

Extensive screening for herbal extracts with potent antioxidant properties  

PubMed Central

This paper summarizes our research for herbal extracts with potent antioxidant activity obtained from a large scale screening based on superoxide radical (O2•?) scavenging activity followed by characterization of antioxidant properties. Firstly, scavenging activity against O2•? was extensively screened from ethanol extracts of approximately 1000 kinds of herbs by applying an electron spin resonance (ESR)-spin trapping method, and we chose four edible herbal extracts with prominently potent ability to scavenge O2•?. They are the extracts from Punica granatum (Peel), Syzygium aromaticum (Bud), Mangifera indica (Kernel), and Phyllanthus emblica (Fruit). These extracts were further examined to determine if they also scavenge hydroxyl radical (•OH), by applying the ESR spin-trapping method, and if they have heat resistance as a desirable characteristic feature. Experiments with the Fenton reaction and photolysis of H2O2 induced by UV irradiation demonstrated that all four extracts have potent ability to directly scavenge •OH. Furthermore, the scavenging activities against O2•? and •OH of the extracts of P. granatum (peel), M. indica (kernel) and P. emblica (fruit) proved to be heat-resistant. The results of the review might give useful information when choosing a potent antioxidant as a foodstuff. For instance, the four herbal extracts chosen from extensive screening possess desirable antioxidant properties. In particular, the extracts of the aforementioned three herbs are expected to be suitable for food processing in which thermal devices are used, because of their heat resistance.

Niwano, Yoshimi; Saito, Keita; Yoshizaki, Fumihiko; Kohno, Masahiro; Ozawa, Toshihiko

2011-01-01

290

Disulfiram is a potent inhibitor of rat 5-lipoxygenase activity.  

PubMed

The effect of disulfiram on the 5-lipoxygenase activity from rat polymorphonuclear leukocyte cell-free lysates was determined and compared with that of other thiocarbamoyl and aryl disulfides. Disulfiram was a potent inhibitor of the soluble 5-lipoxygenase causing 50% inhibition at submicromolar concentrations (0.4-0.7 microM). The inhibition by disulfiram was similar to that of bis(diisopropylthiocarbamoyl) disulfide with both compounds being about 100-fold more potent as inhibitors than the structurally related bis(4-methyl-1-homopiperazinylthiocarbonyl) disulfide analog. The potency of 5-lipoxygenase inhibition by disulfiram was comparable to that of diphenyldisulfide (IC50 = 0.2-0.4 microM), in the same range or better than most typically used inhibitors. However, the degree of inhibition by disulfiram was more sensitive to thiols than that of diphenyldisulfide, as shown by the selective protection against disulfiram inhibition by low concentrations of thiols. Diethyldithiocarbamate, the reduction product of disulfiram, was a less potent inhibitor of the 5-lipoxygenase activity, causing only a partial inhibition (40-60%) over a wide range of concentrations (2-30 microM). The results demonstrate that disulfiram is a potent inhibitor of 5-lipoxygenase in vitro and provide the basis for further investigations on the effect of the drug on leukotriene biosynthesis inhibition and its contribution to the ethanol-disulfiram reaction. They also indicate that disulfiram represents a sensitive reagent to characterize the thiol requirement of the 5-lipoxygenase reaction. PMID:3449208

Choo, L Y; Riendeau, D

1987-12-01

291

Ohmic contacts for wide bandgap semiconductors: Processing, properties and mechanisms  

NASA Astrophysics Data System (ADS)

Stable Ohmic contacts are essential for reliable operation of wide bandgap semiconductor electronic and optoelectronic devices. Such contacts have been made to molecular beam epitaxy (MBE) grown n-type and p-type ZnSe on (100) semi-insulating GaAs substrates and metalorganic chemical vapor deposition (MOCVD) grown p-type GaN on (0001) sapphire substrates. Various metals have been deposited by thermal evaporation and annealing techniques at different temperatures. Chemical etching and cleaning, plasma treatment using reactive ion etching (RIE), and cryogenic treatment in liquid nitrogen have been studied. Ion implantation was also performed to obtain highly doped materials. The electrical characteristics for the contacts were examined by the current versus voltage data and the specific contact resistance was determined by use of the transmission line method (TLM) for II-VI n-type and p-type ZnSe and the circular transmission line method (c-TLM) for III-V p-type GaN, respectively. Contacts formed by In/Au to n-type ZnSe and Cu/Au to p-type ZnSe showed the lowest specific contact resistance values of 1.04 x 10--2 Ocm2 and 1.67 x 10--1 Ocm 2, respectively. A nitrogen plasma treatment of the ZnSe surface prior to metallization was proven to lower the contact resistance to p-type ZnSe. Two different current flow mechanisms involving thermionic emission and thermionic field emission were shown for the Cu/Au contact to low doped p-ZnSe (1 x 1017 cm--3) and three involving thermionic emission, thermionic field emission, and tunneling for the Mg/Au contact to highly doped n-ZnSe (1.15 x 1019 cm--3). MOCVD grown p-type Mg-doped GaN with hole concentration of 1.41 x 1017 cm--3 was used to study Ohmic contacts to p-type GaN. The effects of the cryogenic process on improving Ohmic behavior (I-V linearity) and reducing the specific contact resistance were investigated and may result from a combination of the improved surface morphology and the recrystallizing of new compounds such as NiO and Au:Pd solid solution. The I-V-T measurement for both contacts had similar behavior and closely fit thermionic field emission current mechanisms with little deviation but dominant transport mechanisms were not clear since the contacts were practically Ohmic. (Abstract shortened by UMI.)

Park, Mi-Ran

292

Patterns of Nonresident Father Contact  

PubMed Central

We used the National Longitudinal Survey of Youth 1979 cohort (NLSY79) from 1979 to 2002 and the Children of the National Longitudinal Survey of Youth (CNLSY) from 1986 to 2002 to describe the number, shape, and population frequencies of U.S. nonresident father contact trajectories over a 14-year period using growth mixture models. The resulting four-category classification indicated that nonresident father involvement is not adequately characterized by a single population with a monotonic pattern of declining contact over time. Contrary to expectations, about two-thirds of fathers were consistently either highly involved or rarely involved in their children’s lives. Only one group, constituting approximately 23% of fathers, exhibited a clear pattern of declining contact. In addition, a small group of fathers (8%) displayed a pattern of increasing contact. A variety of variables differentiated between these groups, including the child’s age at father-child separation, whether the child was born within marriage, the mother’s education, the mother’s age at birth, whether the father pays child support regularly, and the geographical distance between fathers and children.

CHEADLE, JACOB E.; AMATO, PAUL R.; KING, VALARIE

2010-01-01

293

Contact Allergy in Agricultural Workers  

Microsoft Academic Search

Agricultural workers (n = 121) referred to the Nofer Institute of Occupational Medicine for suspected occupational disease were subjected to dermatological and allergological examinations. All were patch and prick tested with standard occupational and environmental allergen sets. Contact dermatitis was diagnosed in 60 (49.6%) patients. In the women, the dominant allergy was that to nickel, benzalkonium, palladium, cobalt, thimerosal, fragrances

Marta Kiec-Swierczynska; Beata Krecisz; Dominika Swierczynska-Machura

2003-01-01

294

Allergic contact dermatitis from aromatherapy  

Microsoft Academic Search

Allergic contact dermatitis secondary to aromatherapy has been only rarely reported. We present 39-year-old woman who had used aromatherapy products for approximately 2 to 3 years who presented with an erythematous eruption on her face and chest. Patch testing showed a positive reaction to neomycin and fragrance mix. On cessation of her aromatherapy products, her eruption rapidly resolved. Aromatherapy products

Rochelle R. Weiss; William D. James

1997-01-01

295

Prosodic Change and Language Contact  

ERIC Educational Resources Information Center

Using evidence from first-hand experimental work and existing studies, Colantoni and Gurlekian take a tentative but encouraging step towards exploring the role of contact in explaining intonational change. Their central question is whether Buenos Aires Spanish intonation is distinctive relative to other varieties of Spanish; and if so, whether…

McMahon, April

2004-01-01

296

Composites for electrical contact applications  

Microsoft Academic Search

Materials for use in electrical engineering and electronics are often required to have combinations of properties which are not generally found in pure metals or alloys. For many years metallic composites have been used for electric-contact applications. The paper discusses the physical properties of composites in terms of 'combination properties' (sum properties and product properties) and structural properties (determined by

D. Stoeckel

1979-01-01

297

Barrier/Cu contact resistivity  

SciTech Connect

The specific contact resistivity of Cu with ({alpha} + {beta})-Ta, TiN, {alpha}-W, and amorphous-Ta{sub 36}Si{sub 14}N{sub 50} barrier films is measured using a novel four-point-probe approach. Geometrically, the test structures consist of colinear sets of W-plugs to act as current and voltage probes that contact the bottom of a planar Cu/barrier/Cu stack. Underlying Al interconnects link the plugs to the current source and voltmeter. The center-to-center distance of the probes ranges from 3 to 200 {micro}m. Using a relation developed by Vu et al., a contact resistivity of roughly 7 {times} 10{sup {minus}9} {Omega} cm{sup 2} is obtained for all tested barrier/Cu combinations. By reflective-mode small-angle X-ray scattering, the similarity in contact resistivity among the barrier films may be related to interfacial impurities absorbed from the deposition process.

Reid, J.S.; Nicolet, M.A. [California Inst. of Tech., Pasadena, CA (United States); Angyal, M.S.; Lilienfeld, D.; Shacham-Diamand, Y. [Cornell Univ., Ithaca, NY (United States); Smith, P.M. [Sandia National Labs., Albuquerque, NM (United States)

1995-10-17

298

Contact geometry in Lagrangian mechanics  

NASA Astrophysics Data System (ADS)

We present a picture of Lagrangian mechanics, free of some unnatural features (such as complete divergences). As a byproduct, a completely natural U(1)-bundle over the phase space appears. The correspondence between classical and quantum mechanics is very clear, e.g. no topological ambiguities remain. Contact geometry is the basic tool.

Ševera, Pavol

1999-02-01

299

Contact dermatitis in Israeli soldiers  

Microsoft Academic Search

This report consists of an evaluation of 41 soldiers from the infantry, armored, and artillery division, who developed hand dermatitis from their contact with oils and fuel. A special “tailored” supplementary tray with five reagents relevant to their field of work and environment was performed. The reagents that were used were gun oil, hydraulic oil, automotive lubricant (oil) 20\\/50, white

Ronni Wolf; Moshe Movshowitz; Sarah Brenner

1994-01-01

300

Amorphous Silicon Contact Image Sensor.  

National Technical Information Service (NTIS)

Development was made of a high-speed and high-resolution amorphous silicon contact image sensor with A4 size width, 16 elements/mm and 0.8-ms/line reading speed. It was believed to be difficult to apply amorphous silicon to a high-speed image sensor becau...

Y. Suda K. Suzuki T. Saito

1984-01-01

301

Ground Contact Area Measurement Device.  

National Technical Information Service (NTIS)

The area of contact between a moving load transfer device (such as a wheel or track) and the surface can be rapidly and accurately measured to determine its magnitude and shape for use in evaluating mobility potential or determining appropriate adjustment...

W. E. Brooks

1982-01-01

302

Contact dermatitis to Shiitake mushroom.  

PubMed

A 44-year-old woman with occupational allergic contact dermatitis to Shiitake mushroom (Lentinus edodes), sawdust and thiuram. She presented with an 8-month history of hand and face dermatitis that developed after working for 2.5 years in a mushroom farm. Within 3 months of ceasing work at the farm, her symptoms resolved completely. PMID:12752194

Curnow, Paul; Tam, Mei

2003-05-01

303

Infiltration of Liquid Droplets Into Porous Media: Effects of Dynamic Contact Angle and Contact Angle Hysteresis  

NASA Astrophysics Data System (ADS)

Infiltration of liquid droplets into dry porous media occurs when rain drops fall onto soil, when accidentally spilling organic liquid (e.g., gasoline and chlorinated solvents) onto ground, or when aerosol pesticides are not intercepted by the vegetation and then released to soils. If harmful chemicals are released from the droplet into the atmosphere through evaporation, it is important to know the time of infiltration. We developed a theory for infiltration, which accounts for a general model for the dynamic contact angle between the droplet and the porous medium as well as contact angle hysteresis. Our theory assumes the droplet to have the shape of a spherical cap and the pressure within the droplet to be uniform. The theory shows that droplet infiltration involves three phases due to contact angle hysteresis: (1) an increasing drawing area (IDA) phase during which the interface between the droplet and the porous medium increases, (2) a constant drawing area (CDA) phase during which the contact line of the droplet remains pinned, and (3) a decreasing drawing area (DDA) phase. We find that infiltration always consists of a cascade process formed by the IDA, CDA, and DDA phases, where the entire process may begin or end in any of the three phases. The entire process is formulated with four nondimensional parameters: three contact angles (initial, advancing, and receding) and a porous permeability parameter that depends on porous medium geometry. The total time of infiltration and the time dependence of drawing area are critically affected by the occurrence of the IDA, CDA, and DDA phases as well as by the permeability. In general, the IDA and DDA phases are described by integro-differential equations. With ordinary differential equations (ODEs), we are able to approximate the IDA phase and to describe exactly infiltration processes that starts out with the CDA or DDA phase.

Hilpert, M.

2008-12-01

304

Localized ohmic contact through a passivation dielectric for solar cell rear surface design  

NASA Astrophysics Data System (ADS)

We report the demonstration of a method for forming localized ohmic contact through dielectric passivation layers, via a laser doped region, with no etching prior to metal deposition. A simple bench top voltage source contacted to the gate and bulk of a test Metal-Insulator-Semiconductor device facilitates localized heating leading to ohmic contact formation. The surface passivation qualities of the dielectrics are preserved away from the contact region using this method, as hard dielectric breakdown is restricted to the laser doped region. This is a potential technique for precisely contacting rear surface of high efficiency solar cells.

Western, Ned J.; Sung, Andrew; Wenham, Stuart R.; Bremner, Stephen P.

2013-06-01

305

(+)-Hydrastine, a potent competitive antagonist at mammalian GABAA receptors.  

PubMed Central

1. (+)-Hydrastine is a phthalide isoquinoline alkaloid, isolated from Corydalis stricta. It has the same 1S,9R configuration as the competitive GABAA receptor antagonist bicuculline and is the enantiomer of the commercially available (-)-hydrastine. 2. (+)-Hydrastine (CD50 0.16 mg kg-1, i.v.) was twice as potent as bicuculline (CD50 0.32 mg kg-1, i.v.) as a convulsant in mice. This action was stereoselective in that (+)-hydrastine was 180 times as potent as (-)-hydrastine. 3. (+)-Hydrastine was a selective antagonist at bicuculline-sensitive GABAA receptors in the guinea-pig isolated ileum. It did not influence phaclofen-sensitive GABAB receptors or acetylcholine receptors in this tissue. (+)-Hydrastine was a competitive antagonist of GABAA responses (pA2 6.5) more potent than bicuculline (pA2 6.1). 4. When tested against the binding of [3H]-muscimol to high affinity GABAA binding sites in rat brain membranes, (+)-hydrastine (IC50 2.37 microM) was 8 times more potent than bicuculline (IC50 19.7 microM). 5. As an antagonist of the activation of low affinity GABAA receptors as measured by the stimulation by GABA of [3H]-diazepam binding to rat brain membranes, (+)-hydrastine (IC50 0.4 microM) was more potent than bicuculline (IC50 2.3 microM). 6. (+)-Hydrastine, 10 nM to 1 mM, did not inhibit the binding of [3H]-(-)-baclofen to GABAB binding sites in rat brain membranes.

Huang, J. H.; Johnston, G. A.

1990-01-01

306

Systemic migration of dendritic cells during contact sensitization.  

PubMed Central

Twenty-four hours after skin painting mice on the flank with the contact sensitizer fluorescein isothiocyanate (FITC), the number of dendritic cells (DC) increased sharply, not only in draining but also in contralateral (CLN) and distant lymph nodes. High levels of antigen were detected on up to 50% of DC isolated from draining lymph nodes (DLN), and these cells were potent stimulators of naive T cells in vitro. Less than 3% of DC from contralateral and distant lymph nodes carried detectable antigen and did not induce significant T-cell proliferation. A significant number of DC had migrated to draining, contralateral and distant lymph nodes without acquiring detectable antigen. This indicates that there is a systemic signal causing the movement of DC to lymph nodes. This appears to be independent of mature T cells, as the systemic migration of DC also occurred in nude mice.

Hill, S; Edwards, A J; Kimber, I; Knight, S C

1990-01-01

307

Effect of surface deformations on contact conductance  

Microsoft Academic Search

This study experimentally investigates the influence of surface deformations on contact conductance when two dissimilar metals are brought into contact. Most relations between the contact conductance and the load use the surface hardness to characterize surface deformations. This inherently assumes that deformations are predominantly plastic. To check the validity of this assumption, five tests were conducted in the contact pressure

M. Williamson; A. Majumdar

1992-01-01

308

Contacts conduction and switching in DC levels  

Microsoft Academic Search

Electrical contact conduction and switching capacity are described by contact resistance and subsequent erosion due to arcing. Measurement of these parameters is therefore useful for testing contact materials under various conditions and applications. In various areas, nominal contact resistance, minimum erosion and material transfer are required with low cost materials working in a wide range of currents from 1 mA

N. Ben Jemaa

2002-01-01

309

Impact of fretting parameters on contact degradation  

Microsoft Academic Search

Two previously developed models, dealing with contact resistance and oxide build-up under fretting conditions, were refined and combined into a single analytical model. This model was used to predict the average effects of contact force and fretting amplitude on contact degradation. The results from fretting tests on specially prepared tin plated contacts were explained within the framework of this model.

Robert D. Malucci

1996-01-01

310

Improved Electrical Contact For Dowhhole Drilling Networks  

DOEpatents

An electrical contact system for transmitting information across tool joints while minimizing signal reflections that occur at the tool joints includes a first electrical contact comprising an annular resilient material. An annular conductor is embedded within the annular resilient material and has a surface exposed from the annular resilient material. A second electrical contact is provided that is substantially equal to the first electrical contact. Likewise, the second electrical contact has an annular resilient material and an annular conductor. The two electrical contacts configured to contact one another such that the annular conductors of each come into physical contact. The annular resilient materials of each electrical contact each have dielectric characteristics and dimensions that are adjusted to provide desired impedance to the electrical contacts.

Hall, David R. (Provo, UT); Hall, Jr., H. Tracy (Provo, UT); Pixton, David S. (Lehi, UT); Dahlgren, Scott (Provo, UT); Fox, Joe (Spanish Fork, UT); Sneddon, Cameron (Provo, UT)

2005-08-16

311

Contact Eczema Caused by True Teak (Tectona Grandis)  

PubMed Central

An epidemiological study of occupational contact eczema in a furniture factory is presented. The localization, distribution, and clinical features of the skin lesions were characteristic of contact eczema caused by a sensitizing or irritating dust. True teak—Tectona grandis—was the cause of the skin condition. That teak is a fairly potent sensitizer and also contains primary irritants is fully confirmed by the present study. About half the employees who were heavily exposed to teak dust suffered from eczema and/or severe itching. Only 8% of those with slight exposure to teak dust experienced skin symptoms. Patch tests with native teak dust moistened with water were applied on 10 “controls” and 112 workers who were exposed to teak in various working procedures. Moistened teak dust produced toxic reactions in 20·5%, while native teak dust did not have primary irritant effects and was, therefore, considered to be the substance of choice for patch testing; 18·7% of the workers showed an allergic skin reaction to native teak dust. The diagnosis of allergic contact eczema was made in 12·5%, and 6·2% were considered to have latent allergy. Primary irritant (contact) eczema was considered to be present in four individuals who had experienced acute, transitory, eczematous eruptions during the hot part of the summer when they perspired freely. In these cases the patch test to native teak dust was negative. Desensitization or “hardening” was observed in four workers. In most cases the skin lesions were not severe enough to cause sickness absence. The cause of the relatively high percentage of sensitization to teak among the workers in the factory is discussed. The importance of suitable prophylactic measures is stressed.

Krogh, H. K.

1962-01-01

312

A direct measurement of interfacial contact resistance  

Microsoft Academic Search

A method is described for directly measuring interfacial contact resistance and estimating the degree of uniformity of the interfacial layer in metal-semiconductor contacts. A two-dimensional resistor network model is used to obtain a relationship between the specific contact resistance and the measured interfacial contact resistance for contacts with a homogeneous interfacial layer. Measurement results are given for 98.5% Al\\/1.5% Si

S. J. Proctor; L. W. Linholm

1982-01-01

313

Context-aware communication with Live Contacts  

Microsoft Academic Search

We demonstrate Live Contacts, a .NET-based context-aware communication application that runs on Pocket PC phones, Smartphones and desktop PCs. In just four clicks, Live Contacts helps you to contact the right person at the right time via the right communication channel. To achieve this, Live Contacts provides up-to-date context information about your most important contacts, including instant messaging status, current

G. Henri; Raymond A. A. Otte; Hans C. J. Kruse; Martin Snijders

314

Simulation of contact in finite deformation problems – algorithm  

Microsoft Academic Search

Numerous problems, involving finite deformation, necessitate an accurate treatment of sliding interface boundaries and impact conditions. Excellent examples of such problems may be found in the areas of radioactive waste transportation package qualification, crashworthiness, fluid-structure interaction and various manufacturing processes including metal forming and cutting. Large scale nonlinear simulations involving arbitrary contact continues to pose a number of challenging issues.

R. G. SAUVE ´; G. D. Morandin

2004-01-01

315

Electrical contacts and conductors for megaamperes pulse currents  

Microsoft Academic Search

Summary form only given. The operation of electrical contacts and conductors in output circuits of pulse current sources, which generate current pulses of several megaamperes and duration of tens or hundreds microseconds, are considered. The admissible linear current density in conductors is defined from condition of the thermal stability of polymeric insulation. Such density is 160 kA\\/cm for steel, copper

B. E. Fridman; P. G. Rutberg

2001-01-01

316

Contact properties of a wet clutch friction material  

Microsoft Academic Search

Wet clutches are required to transmit torque and also prevent motion in automatic transmissions. Their performance is critically dependent on a friction material which comprises one of the contacting surfaces. Friction materials are usually a composite of fibres, naturally occurring minerals and particles of silicon and graphite, which are all bonded together with a resin. The material formed has very

M. Ingram; H. Spikes; J. Noles; R. Watts

2010-01-01

317

Method and apparatus for producing co-current fluid contact  

DOEpatents

An improved packing system and method are disclosed wherein a packing section includes a liquid distributor and a separator placed above the distributor so that gas rising through the liquid distributor contacts liquid in the distributor, forming a gas-liquid combination which rises in co-current flow to the separator. Liquid is collected in the separator, from which gas rises.

Trutna, William R. (6 Postwood, Austin, TX 78738-1503)

1997-01-01

318

Contact angle effects on microdroplet deformation using CFD  

Microsoft Academic Search

In this paper we use computational fluid dynamics (CFD) to study the effect of contact angle on droplet shape as it moves through a contraction. A new non-dimensional number is proposed in order to predict situations where the deformed droplet will form a slug in the contraction and thus have the opportunity to interact with the channel wall. It is

G. Rosengarten; D. J. E. Harvie; J. Cooper-White

2006-01-01

319

Electron transport in molecular wires with transition metal contacts  

Microsoft Academic Search

A molecular wire is an organic molecule that forms a conducting bridge between electronic contacts. Single molecules are likely to be the smallest entities to conduct electricity and thus molecular wires present many interesting challenges to fundamental science as well as enormous potential for nanoelectronic technological applications. A particular challenge stems from the realization that the properties of molecular wires

Hugh Dalgleish

2006-01-01

320

Remedial Action Contacts Directory - 1997  

SciTech Connect

This document, which was prepared for the US Department of Energy (DOE) Office of Environmental Restoration (ER), is a directory of 2628 individuals interested or involved in environmental restoration and/or remedial actions at radioactively contaminated sites. This directory contains a list of mailing addresses and phone numbers of DOE operations, area, site, project, and contractor offices; an index of DOE operations, area, site, project, and contractor office sorted by state; a list of individuals, presented by last name, facsimile number, and e-mail address; an index of affiliations presented alphabetically, with individual contacts appearing below each affiliation name; and an index of foreign contacta sorted by country and affiliation. This document was generated from the Remedial Action Contacts Database, which is maintained by the Remedial Action Program Information Center (RAPIC).

NONE

1997-05-01

321

Sensing with Superconducting Point Contacts  

PubMed Central

Superconducting point contacts have been used for measuring magnetic polarizations, identifying magnetic impurities, electronic structures, and even the vibrational modes of small molecules. Due to intrinsically small energy scale in the subgap structures of the supercurrent determined by the size of the superconducting energy gap, superconductors provide ultrahigh sensitivities for high resolution spectroscopies. The so-called Andreev reflection process between normal metal and superconductor carries complex and rich information which can be utilized as powerful sensor when fully exploited. In this review, we would discuss recent experimental and theoretical developments in the supercurrent transport through superconducting point contacts and their relevance to sensing applications, and we would highlight their current issues and potentials. A true utilization of the method based on Andreev reflection analysis opens up possibilities for a new class of ultrasensitive sensors.

Nurbawono, Argo; Zhang, Chun

2012-01-01

322

Contact microscopy with synchrotron radiation  

SciTech Connect

Soft x-ray contact microscopy with synchrotron radiation offers the biologist and especially the microscopist, a way to morphologically study specimens that could not be imaged by conventional TEM, STEM or SEM methods (i.e. hydrated samples, samples easily damaged by an electron beam, electron dense samples, thick specimens, unstained low contrast specimens) at spatial resolutions approaching those of the TEM, with the additional possibility to obtain compositional (elemental) information about the sample as well. Although flash x-ray sources offer faster exposure times, synchrotron radiation provides a highly collimated, intense radiation that can be tuned to select specific discrete ranges of x-ray wavelengths or specific individual wavelengths which optimize imaging or microanalysis of a specific sample. This paper presents an overview of the applications of x-ray contact microscopy to biological research and some current research results using monochromatic synchrotron radiation to image biological samples. 24 refs., 10 figs.

Panessa-Warren, B.J.

1985-10-01

323

Nickel silicide for Ni/Cu contact mono-silicon solar cells  

NASA Astrophysics Data System (ADS)

A solar cell contact needs to be as thin as possible and have high conductivity since a thick contact causes shading loss and reduced current. Plating is a very suitable method for making a metal contact, and nickel is a high conductivity metal which is easy to form into a contact using electroless plating. After the nickel is plated on the silicon substrate, the nickel contact should be fired in order to form nickel silicide. Nickel silicide is used for the seed layer of the Cu contact for silicon solar cells. In this study, we replaced the screen-printed contact of the Passivated Emitter Solar Cell (PESC) with a Ni/Cu contact that has a selective emitter. The nickel layer was used as the seed layer, adhesion layer, and Cu diffusion barrier. The main contact was formed by plating the copper. The firing conditions of a conventional furnace were varied in order to form nickel silicide. Consequently, we achieved the best solar cell efficiency of 18.15%.

Min, Seon Kyu; Kim, Dong Ho; Lee, Soo Hong

2013-07-01

324

Contact dermatitis in hairdressers' clients.  

PubMed

The aim of our study was to report the frequency of sensitization to hairdressing allergens in a group of patients with contact dermatitis, in whom previous treatments with hair dyes or permanent wave solutions were suspected to be the cause. 49 of 261 hairdressers' clients (18.7%), who were patch tested with the hairdressers' screening series in the years 1985-1990, showed one (27) or more (22) positive reactions to hairdressing chemicals. This study confirms hair dyeing to be the procedure associated with the highest risk of sensitization among hairdressers' clients. Among hair dye allergens, PPD is the most frequent sensitizer (7.3%). A low rate of sensitization to the PPD derivatives PAP, ONPPD and PTD was detected in these clients, there being no differences in the frequency of sensitization to the 3 substances (4.2%, 4.6% and 4.6%, respectively). Only 0.4% of clients were positive to resorcinol, while pyrogallol showed a 2.3% rate of sensitization. Sensitization to GMTG was found in 3.3% of patients. ATG was an infrequent sensitizer (1.1%). Allergic contact dermatitis due to APS is quite rare (2.7%), in view of the widespread use of this compound. A positive open patch test in 1 hairdressers' client, who complained of generalized urticaria after hair bleaching, confirmed the diagnosis of immediate contact reaction due to APS. Sensitization to hairdressing allergens among consumers (18.7%) is possibly more frequent than sensitization to other cosmetic ingredients. We previously detected a 14.3% rate of sensitization to cosmetic ingredients in patients with suspected allergic contact dermatitis caused by cosmetics. On the other hand, reactions to cosmetic ingredients were also common in our patients. This may indicate that hairdressers' clients make greater use of cosmetics than average. PMID:1633700

Guerra, L; Bardazzi, F; Tosti, A

1992-02-01

325

Allergic Contact Dermatitis: Rubber Allergies  

Microsoft Academic Search

\\u000a Latex (rubber) allergy is a growing health concern among medical and nonmedical fields. Common occupational exposures include,\\u000a health care and food industry workers using disposable gloves, latex industry employees, and car ­factory workers assembling\\u000a rubber details. Additionally, high-risk groups include children with spina bifida or spinal dysraphism. Risk factors for latex\\u000a allergic ­contact dermatitis (ACD) include skin damage allowing increased

Peter Burke; Howard I. Maibach

326

Contact dermatitis: facts and controversies.  

PubMed

The history of contact dermatitis (CD) is inseparable from the history of the patch test, and the patch test is inseparable from the pioneer in the field, Josef Jadassohn (1860-1936). Despite the fact that we have been diagnosing, treating, and investigating the condition for more than 100 years, there are still many unsolved questions and controversies, which show no signs of coming to an end in the foreseeable future. This contribution reviews and highlights some of the disagreements and discrepancies associated with CD. For example: • What is the real sensitizer in balsam of Peru, one of the most common allergens, and what, if any, is the value of a low-balsam diet? • Is benzalkonium chloride, which has well-known and undisputed irritant properties, a contact allergen as well? • Is cocamidopropyl betaine (CABP) a common contact allergen and what is the actual sensitizer in CABP allergy the molecule itself, or impurities, or intermediaries in its synthesis? • How can the significant differences in the prevalence of sensitization of formaldehyde (FA, a common cause of contact allergy) between the United States (8%-9%) and Europe (2%-3%) be explained? • What is the relationship between formaldehyde releasers (FRs) allergy and an FA allergy? Should we recommend that FA-allergic patients also avoid FRs, and, if so, to what extent? • What is the true frequency of lanolin allergy? This issue remains enigmatic despite the expenditure of thousands of dollars and the innumerable hours spent investigating this subject. • What is the basis behind the so-called "lanolin paradox"? This label was coined in 1996 and is still a matter of controversy. • Is there such a thing as systemic CD from nickel, and, if so, to what extent? Is there a cross-reactivity or concomitant sensitization between nickel and cobalt?These are some of the controversial problems discussed. We have selected the ones that we consider to be of special interest and importance to the practicing dermatologist. PMID:23806164

Wolf, Ronni; Orion, Edith; Ruocco, Eleonora; Baroni, Adone; Ruocco, Vincenzo

327

Contact sensitivity in atopic dermatitis  

Microsoft Academic Search

Background: There is some debate about whether the prevalence of contact allergy in patients with atopic dermatitis is the same as in the general population.Objective: The aim of this study was to estimate the prevalence of allergic and irritant patch test reactions in patients with atopic dermatitis and to relate these to clinical patterns of disease.Methods: One hundred twenty-two patients

Fiona M. Lewis; Manu Shah; David J. Gawkrodger

1995-01-01

328

Understanding the structure of the first atomic contact in gold  

PubMed Central

We have studied experimentally jump-to-contact (JC) and jump-out-of-contact (JOC) phenomena in gold electrodes. JC can be observed at first contact when two metals approach each other, while JOC occurs in the last contact before breaking. When the indentation depth between the electrodes is limited to a certain value of conductance, a highly reproducible behaviour in the evolution of the conductance can be obtained for hundreds of cycles of formation and rupture. Molecular dynamics simulations of this process show how the two metallic electrodes are shaped into tips of a well-defined crystallographic structure formed through a mechanical annealing mechanism. We report a detailed analysis of the atomic configurations obtained before contact and rupture of these stable structures and obtained their conductance using first-principles quantum transport calculations. These results help us understand the values of conductance obtained experimentally in the JC and JOC phenomena and improve our understanding of atomic-sized contacts and the evolution of their structural characteristics.

2013-01-01

329

Thermal conductance of a pressed Al-Al contact  

NASA Astrophysics Data System (ADS)

Thermal conductance of a screw-fastened joint between two blocks of Al-alloys has been measured. An AlMg4.5Mn-block, the end of which is cooled by liquid helium, constitutes the upper part of the sample and the contact is formed at the face surface of a cylindrical extension of that block onto which a cylinder, made of AlMgSi1, is pressed by means of a copper-nickel screw. Pressing of the contact was carried out at room temperature by applying a defined torque, M, to the fastening screw. Three samples of the same shape but with differently treated surfaces of contact (machined flat, electro-chemically polished, with gold plated contacts) were studied. The results showed that the machined flat surfaces yield the best contact and that the contact conductance (measured in the range 4.2 K to 1.8 K) of all samples increased with increasing torque. In addition to thermal measurements, a study of the electrical conductance would be very interesting to determine the different contributions of phonon and electron heat conduction by means of the Wiedemann-Franz law. The work is useful for the GIRL (German Infra-Red Laboratory) space experiment.

Wanner, M.

1981-01-01

330

Understanding the structure of the first atomic contact in gold  

NASA Astrophysics Data System (ADS)

We have studied experimentally jump-to-contact (JC) and jump-out-of-contact (JOC) phenomena in gold electrodes. JC can be observed at first contact when two metals approach each other, while JOC occurs in the last contact before breaking. When the indentation depth between the electrodes is limited to a certain value of conductance, a highly reproducible behaviour in the evolution of the conductance can be obtained for hundreds of cycles of formation and rupture. Molecular dynamics simulations of this process show how the two metallic electrodes are shaped into tips of a well-defined crystallographic structure formed through a mechanical annealing mechanism. We report a detailed analysis of the atomic configurations obtained before contact and rupture of these stable structures and obtained their conductance using first-principles quantum transport calculations. These results help us understand the values of conductance obtained experimentally in the JC and JOC phenomena and improve our understanding of atomic-sized contacts and the evolution of their structural characteristics.

Sabater, Carlos; Caturla, María José; Palacios, Juan José; Untiedt, Carlos

2013-05-01

331

Understanding the structure of the first atomic contact in gold.  

PubMed

: We have studied experimentally jump-to-contact (JC) and jump-out-of-contact (JOC) phenomena in gold electrodes. JC can be observed at first contact when two metals approach each other, while JOC occurs in the last contact before breaking. When the indentation depth between the electrodes is limited to a certain value of conductance, a highly reproducible behaviour in the evolution of the conductance can be obtained for hundreds of cycles of formation and rupture. Molecular dynamics simulations of this process show how the two metallic electrodes are shaped into tips of a well-defined crystallographic structure formed through a mechanical annealing mechanism. We report a detailed analysis of the atomic configurations obtained before contact and rupture of these stable structures and obtained their conductance using first-principles quantum transport calculations. These results help us understand the values of conductance obtained experimentally in the JC and JOC phenomena and improve our understanding of atomic-sized contacts and the evolution of their structural characteristics. PMID:23718316

Sabater, Carlos; Caturla, María José; Palacios, Juan José; Untiedt, Carlos

2013-05-29

332

Immunotherapy of allergic contact dermatitis.  

PubMed

The term 'immunotherapy' refers to treating diseases by inducing, enhancing or suppressing immune responses. As allergy is an excessive, detrimental immune reaction to otherwise harmless environmental substances, immunotherapy of allergic disease is aimed at the induction of tolerance toward sensitizing antigens. This article focuses on the historical developments, present state and future outlook for immunotherapy with haptens as a therapeutic modality for allergic contact dermatitis. Inspired by the effectiveness of immunotherapy in respiratory allergies, attempts were undertaken at curing allergic contact dermatitis by means of controlled administration of the sensitizing haptens. Animal and human experiments confirmed that tolerance to haptens can be induced most effectively when the induction of tolerance precedes attempted sensitization. In real life, however, therapy is sought by people who are already sensitized and an effective reversal of hypersensitivity seems more difficult to achieve. Decades of research on Rhus hypersensitivity led to a conclusion that immunotherapy can suppress Rhus dermatitis, however, only to a limited degree, for a short period of time, and at a high risk of side effects, which makes this method therapeutically unprofitable. Methodological problems with most available studies of immunotherapy of contact allergy to nickel make any definite conclusions impossible at this stage. PMID:21843085

Spiewak, Radoslaw

2011-08-01

333

Electrical contact resistance as a diagnostic tool for MEMS contact interfaces  

Microsoft Academic Search

The electrical contact resistance (ECR) was evaluated as an in situ diagnostic tool for the contact interface behavior of microelectromechanical systems (MEMS). Special polycrystalline silicon (polysilicon) MEMS devices fabricated by surface micromachining were used to study polysilicon\\/native oxide\\/polysilicon contact interfaces. ECR measurements obtained during monotonic contact loading and unloading and cyclic contact loading are interpreted in the context of a

Ari Lumbantobing; Lior Kogut; Kyriakos Komvopoulos

2004-01-01

334

Measurement of Contact Resistance Distribution in Fretting Corrosion Track for the Tin Plated Contacts  

Microsoft Academic Search

It is observed that contact resistance of tin plated contact in automotive connectors increased due to fretting corrosion, which is originated from heat cycle or vibration. In this study, the measurement condition is established to obtain the contact resistance distribution on fretting corrosion trace of tin plated contact in order to clarify the relationship between contact resistance and oxide formation.

Soushi Masui; Shigeru Sawada; Terutaka Tamai; Yasuhiro Hattori; Kazuo Iida

2011-01-01

335

Contact analysis of three-dimensional rough surfaces under frictionless and frictional contact  

Microsoft Academic Search

A methodology for surface and sub-surface stress calculation of nominally flat on flat rough surface contact has been developed. This methodology is applicable for both large area contact (Hertzian contact) and small area of asperity contact (point load contact) with and without surface friction. A total of nine rough surfaces are generated by the computer with specified standard deviation of

Maria M.-H. Yu; Bharat Bhushan

1996-01-01

336

Novel potent and efficacious nonpeptidic urotensin II receptor agonists.  

PubMed

Six different series of nonpeptidic urotensin II receptor agonists have been synthesized and evaluated for their agonistic activity in a cell-based assay (R-SAT). The compounds are ring-opened analogues of the isochromanone-based agonist AC-7954 with different functionalities constituting the linker between the two aromatic ring moieties. Several of the compounds are highly potent and efficacious, with N-[1-(4-chlorophenyl)-3-(dimethylamino)-propyl]-4-phenylbenzamide oxalate (5d) being the most potent. The pure enantiomers of 5d were obtained from the corresponding diastereomeric amides. It was shown by a combination of X-ray crystallography and chemical correlation that the activity resides in the S-enantiomer of 5d (pEC(50) 7.49). PMID:16570919

Lehmann, Fredrik; Pettersen, Anna; Currier, Erika A; Sherbukhin, Vladimir; Olsson, Roger; Hacksell, Uli; Luthman, Kristina

2006-04-01

337

Synthesis of Unsymmetrical Biphenyls as Potent Cytotoxic Agents  

PubMed Central

Twenty-six unsymmetrical biphenyls were synthesized and evaluated for cytotoxic activity against DU145, A547, KB and KB-Vin tumor cell lines. Three compounds 27, 35 and 40 showed very potent activity against the HTCL panel with an IC50 value range of 0.04–3.23 µM. In addition, fourteen active compounds were all more potent against the drug-resistant KB-Vin cell line than the parental KB cell line. Preliminary SAR analysis indicated that two bulky substituents on the 2,2?-positions of unsymmetrical biphenyl skeleton are necessary and crucial for in vitro anticancer activity, thus providing a good starting point to develop unsymmetrical biphenyls as novel anticancer agents.

Wu, Gang; Guo, Huan-Fang; Gao, Kun; Liu, Yi-Nan; Bastow, Kenneth F.; Morris-Natschke, Susan L.; Lee, Kuo-Hsiung; Xie, Lan

2008-01-01

338

Betulinic acid, a natural compound with potent anticancer effects.  

PubMed

New therapies using novel mechanisms to induce tumor cell death are needed with plants playing a crucial role as a source for potential anticancer compounds. One highly promising class of natural compounds are the triterpenoids with betulinic acid (BetA) as the most prominent representative. In-vitro studies have identified this agent as potently effective against a wide variety of cancer cells, also those derived from therapy-resistant and refractory tumors, whereas it has been found to be relatively nontoxic for healthy cells. In-vivo preclinically applied BetA showed some remarkable anticancer effects and a complete absence of systemic toxicity in rodents. BetA also cooperated with other therapies to induce tumor cell death and several potent derivatives have been discovered. Its antitumor activity has been related to its direct effects on mitochondria where it induces Bax/Bak-independent cytochrome-c release. PMID:20075711

Mullauer, Franziska B; Kessler, Jan H; Medema, Jan Paul

2010-03-01

339

Electron transport in molecular wires with transition metal contacts  

NASA Astrophysics Data System (ADS)

A molecular wire is an organic molecule that forms a conducting bridge between electronic contacts. Single molecules are likely to be the smallest entities to conduct electricity and thus molecular wires present many interesting challenges to fundamental science as well as enormous potential for nanoelectronic technological applications. A particular challenge stems from the realization that the properties of molecular wires are strongly influenced by the combined characteristics of the molecule and the metal contacts. While gold has been the most studied contact material to date, interest in molecular wires with transition metal contacts that are electronically more complex than gold is growing. This thesis presents a theoretical investigation of electron transport and associated phenomena in molecular wires with transition metal contacts. An appropriate methodology is developed on the basis of Landauer theory and ab initio and semi-empirical considerations and new, physically important systems are identified. Spin-dependent transport mechanisms and device characteristics are explored for molecular wires with ferromagnetic iron contacts, systems that have not been considered previously, either theoretically or experimentally. Electron transport between iron point contacts bridged by iron atoms is also investigated. Spin-dependent transport is also studied for molecules bridging nickel contacts and a possible explanation of some experimentally observed phenomena is proposed. A novel physical phenomenon termed strong spin current rectification and a new controllable negative differential resistance mechanism with potential applications for molecular electronic technology are introduced. The phenomena predicted in this thesis should be accessible to present day experimental techniques and this work is intended to stimulate experiments directed at observing them. Keywords. molecular electronics; spintronics; electron transport; interface states.

Dalgleish, Hugh

340

Contact structure for use in catalytic distillation  

DOEpatents

A method and apparatus are disclosed for conducting catalytic chemical reactions and fractionation of the reaction mixture, comprising and feeding reactants into a distillation column reactor contracting said reactant in a liquid phase with a fixed bed catalyst in the form of a contact catalyst structure, consisting of closed porous containers containing the catalyst for the reaction and a clip means to hold and support said containers, which are disposed above, i.e., on the distillation trays in the tower. The trays have weir means to provide a liquid level on the trays to substantially cover the containers. In other words, the trays function in their ordinary manner with the addition thereto of the catalyst. The reaction mixture is concurrently fractionated in the column. 7 figs.

Jones, E.M. Jr.

1985-08-20

341

Contact structure for use in catalytic distillation  

DOEpatents

A method is described for conducting catalytic chemical reactions and fractionation of the reaction mixture comprising feeding reactants into a distillation column reactor, contracting said reactant in liquid phase with a fixed bed catalyst in the form of a contact catalyst structure consisting of closed porous containers containing the catalyst for the reaction and a clip means to hold and support said containers, which are disposed above, i.e., on the distillation trays in the tower. The trays have weir means to provide a liquid level on the trays to substantially cover the containers. In other words, the trays function in their ordinary manner with the addition thereto of the catalyst. The reaction mixture is concurrently fractionated in the column. 7 figs.

Jones, E.M. Jr.

1984-03-27

342

Contact process with sublattice symmetry breaking.  

PubMed

We study a contact process with creation at first- and second-neighbor sites and inhibition at first neighbors, in the form of an annihilation rate that increases with the number of occupied first neighbors. Mean-field theory predicts three phases: inactive (absorbing), active symmetric, and active asymmetric, the latter exhibiting distinct sublattice densities on a bipartite lattice. These phases are separated by continuous transitions; the phase diagram is re-entrant. Monte Carlo simulations in two dimensions verify these predictions qualitatively, except for a first-neighbor creation rate of zero. (In the latter case one of the phase transitions is discontinuous.) Our numerical results confirm that the symmetric-asymmetric transition belongs to the Ising universality class, and that the active-absorbing transition belongs to the directed percolation class, as expected from symmetry considerations. PMID:21867131

de Oliveira, Marcelo Martins; Dickman, Ronald

2011-07-18

343

Method for manufacturing electrical contacts for a thin-film semiconductor device  

DOEpatents

A method of fabricating spaced-apart back contacts on a thin film of semiconductor material by forming strips of buffer material on top of the semiconductor material in locations corresponding to the desired dividing lines between back contacts, forming a film of metal substantially covering the semiconductor material and buffer strips, and scribing portions of the metal film overlying the buffer strips with a laser without contacting the underlying semiconductor material to separate the metal layer into a plurality of back contacts. The buffer material serves to protect the underlying semiconductor material from being damaged during the laser scribing. Back contacts and multi-cell photovoltaic modules incorporating such back contacts also are disclosed.

Carlson, David E. (Yardley, PA); Dickson, Charles R. (Pennington, NJ); D' Aiello, Robert V. (East Brunswick, NJ)

1988-11-08

344

Potent norovirus inhibitors based on the acyclic sulfamide scaffold  

PubMed Central

The development of small molecule therapeutics to combat norovirus infection is of considerable interest from a public health perspective because of the highly contagious nature of noroviruses. A series of amino acid-derived acyclic sulfamide-based norovirus inhibitors has been synthesized and evaluated using a cell-based replicon system. Several compounds were found to display potent anti-norovirus activity, low toxicity, and good aqueous solubility. These compounds are suitable for further optimization of pharmacological and ADMET properties.

Dou, Dengfeng; Tiew, Kok-Chuan; Rao Mandadapu, Sivakoteswara; Reddy Gunnam, Mallikarjuna; Alliston, Kevin R.; Kim, Yunjeong; Chang, Kyeong-Ok; Groutas, William C.

2013-01-01

345

Dynorphin(1-13), an Extraordinarily Potent Opioid Peptide  

Microsoft Academic Search

We describe the opioid properties of a tridecapeptide, the sequence of which corresponds to the NH2-terminal sequence of dynorphin, a novel porcine pituitary endorphin. It contains [Leu]enkephalin. In the guinea pig ileum longitudinal muscle preparation it is about 700 times more potent than [Leu]enkephalin. Its effects in this tissue are blocked completely by naloxone, but the apparent affinity of naloxone

Avram Goldstein; S. Tachibana; L. I. Lowney; M. Hunkapiller; L. Hood

1979-01-01

346

Species-Specific Detoxification Metabolism of Fenpyroximate, a Potent Acaricide  

Microsoft Academic Search

The mode of selective toxicity of fenpyroximate (tert-butyl (E)-?-(1,3-dimethyl-5-phenoxypyrazol-4-ylmethyleneamino-oxy)-p-toluate), a potent acaricide, was studied with respect to its detoxification metabolism. Among its metabolites examined, only ester hydrolyzed metabolites completely lost the inhibitory activity toward NADH–ubiquinone oxidoreductase, which suggested that ester hydrolysis was the key step in detoxification. After a single oral administration of fenpyroximate to rats, two labile intermediates (metabolites

Kazuhiko Motoba; Hideo Nishizawa; Takashi Suzuki; Hiroshi Hamaguchi; Matazaemon Uchida; Shunji Funayama

2000-01-01

347

A Potent Activator of Melanogenesis Identified from Small Molecule Screening  

PubMed Central

Small molecules that increase the cellular level of melanin can be used to study melanogenesis, and have therapeutic potential for melanin-related diseases such as albinism. We describe the identification of a potent activator of melanogenesis from a targeted combinatorial library. Treating melanocytes with our most active molecule results in a 1.8-fold increase in melanin, and an increase in tyrosinase-catalyzed oxidation of L-tyrosine, a key step in melanin biosynthesis.

McNaughton, Brian R.; Gareiss, Peter C.; Jacobs, Stacey E.; Fricke, Alex F.; Scott, Glynis A.

2012-01-01

348

Biaryl analogues of teriflunomide as potent DHODH inhibitors.  

PubMed

The structure-activity relationships of a novel series of biaryl dihydroorotate dehydrogenase (DHODH) inhibitors related to teriflunomide are disclosed. These biaryl derivatives were the result of structure-based design and proved to be potent DHODH inhibitors which in addition showed good antiproliferative activities on peripheral blood mononuclear cells and good efficacies in vivo in the rat adjuvant-induced-arthritis model. PMID:22078215

Erra, Montse; Moreno, Imma; Sanahuja, Jordi; Andrés, Miriam; Reinoso, Raquel F; Lozoya, Estrella; Pizcueta, Pilar; Godessart, Núria; Castro-Palomino, Julio Cesar

2011-10-20

349

RFI641, a Potent Respiratory Syncytial Virus Inhibitor  

Microsoft Academic Search

Human respiratory syncytial virus (RSV), a paramyxovirus, is a major cause of acute upper and lower respiratory tract infections in infants, young children, and adults. RFI-641 is a novel anti-RSV agent with potent in vitro and in vivo activity. RFI-641 is active against both RSV type A and B strains. The viral specificity and the large therapeutic window of RFI-641

Clayton C. Huntley; William J. Weiss; Anna Gazumyan; Aron Buklan; Boris Feld; William Hu; Thomas R. Jones; Timothy Murphy; Antonia A. Nikitenko; Bryan O'Hara; Gregory Prince; Susan Quartuccio; Yuri E. Raifeld; Philip Wyde; John F. O'Connell

2002-01-01

350

A novel potent vasoconstrictor peptide produced by vascular endothelial cells  

Microsoft Academic Search

An endothelium-derived 21-residue vasoconstrictor peptide, endothelin, has been isolated, and shown to be one of the most potent vasoconstrictors known. Cloning and sequencing of preproendothelin complementary DNA shows that mature endothelin is generated through an unusual proteolytic processing, and regional homologies to a group of neurotoxins suggest that endothelin is an endogenous modulator of voltage-dependent ion channels. Expression of the

Masashi Yanagisawa; Hiroki Kurihara; Sadao Kimura; Yoko Tomobe; Mieko Kobayashi; Youji Mitsui; Yoshio Yazaki; Katsutoshi Goto; Tomoh Masaki

1988-01-01

351

Potent antioxidant dendrimers lacking pro-oxidant activity  

Microsoft Academic Search

It is well known that antioxidants have protective effects against oxidative stress. Unfortunately, in the presence of transition metals, antioxidants, including polyphenols with potent antioxidant activities, may also exhibit pro-oxidant effects, which may irreversibly damage DNA. Therefore, antioxidants with strong free radical-scavenging abilities and devoid of pro-oxidant effects would be of immense biological importance. We report two antioxidant dendrimers with

Choon Young Lee; Ajit Sharma; Rebecca L. Uzarski; Jae Eun Cheong; Hao Xu; Rich A. Held; Samik K. Upadhaya; Julie L. Nelson

2011-01-01

352

The discovery of sulfonylated dipeptides as Potent VLA4 antagonists  

Microsoft Academic Search

Directed screening of a carboxylic acid-containing combinatorial library led to the discovery of potent inhibitors of the integrin VLA-4. Subsequent optimization by solid-phase synthesis afforded a series of sulfonylated dipeptide inhibitors with structural components that when combined in a single hybrid molecule gave a sub-nanomolar inhibitor as a lead for medicinal chemistry. Preliminary metabolic studies led to the discovery of

William K Hagmann; Philippe L Durette; Thomas Lanza; Nancy Jo Kevin; Stephen E de Laszlo; Ihor E Kopka; David Young; Plato A Magriotis; Bing Li; Linus S Lin; Ginger Yang; Theodore Kamenecka; Linda L Chang; Jonathan Wilson; Malcolm MacCoss; Sander G Mills; Gail Van Riper; Ermengilda McCauley; Linda A Egger; Usha Kidambi; Kathryn Lyons; Stella Vincent; Ralph Stearns; Adria Colletti; Johannes Teffera; Sharon Tong; Judy Fenyk-Melody; Karen Owens; Dorothy Levorse; Philip Kim; John A Schmidt; Richard A Mumford

2001-01-01

353

A new anthracycline with potent antileukemic activity exhibits reduced mutagenicity  

Microsoft Academic Search

The mutagenicity of a new anthracycline (moflomycin) with potent antileukemic activity was studied by the Ames test in four strains of Salmonella typhimurium (TA97a, TA98, TA100 and TA102), and compared to the mutagenicity of doxorubicin, widely used as antineoplastic agent. Unlike doxorubicin, moflomycin displayed no mutagenic activity in strains TA98 and TA100. Low mutagenicity was only observed in TA102 strain

William Andrivon; Francoise Callais; Joëlle Nafziger; Claude Monneret; Jean Jacques Guillosson

1995-01-01

354

Evaluation of a potent inhibitor of subprimate and primate renins.  

PubMed

Our attempts to synthesize a potent inhibitor of rat renin have resulted in the discovery of CGP 44 099 A, a potent inhibitor of plasma renin from all subprimate species tested so far [IC50 (in nM): dog, 0.007; rabbit, 0.033; guinea pig, 0.34; mouse, 0.4; cat, 0.57; and rat, 1.3]. This compound is also a potent inhibitor of primate renins [IC50 (in nM): human, 0.3; and marmoset, 1.4]. It is less potent against other aspartic proteinases [IC50 (in nM): porcine pepsin, 26; and bovine cathepsin D, 230). CGP 44 099 A exhibited a competitive mode of inhibition against human renin (Ki, 0.12 nM). During i.v. infusion of CGP 44 099 A in sodium-depleted normotensive rats (0.1 mg/kg/min) blood pressure (BP) was lowered by about 25 mm Hg. Plasma renin activity, angiotensin I and angiotensin II were almost completely suppressed. The converting enzyme inhibitor enalaprilat (1 mg/kg i.v.) also lowered BP by about 25 mm Hg. No further fall in BP occurred when CGP 44 099 A (0.1 mg/kg/min) was infused after pretreatment with enalaprilat (1 mg/kg i.v.) and CGP 44 099 A did not lower BP when infused in bilaterally nephrectomized rats. These results indicate that the hypotensive response induced by CGP 44 099 A in sodium-depleted rats is specifically due to the renin inhibition. Compounds such as CGP 44 099 may therefore be useful for comparing the effects of renin inhibition in different species and for studying the role of renin in various models of cardiovascular disease in nonprimate species. PMID:2110974

Wood, J M; Mah, S C; Baum, H P; de Gasparo, M; Cumin, F; Rüeger, H; Nussberger, J

1990-05-01

355

Direct-Write Contacts: Metallization and Contact Formation; Preprint  

SciTech Connect

Using direct-write approaches in photovoltaics for metallization and contact formation can significantly reduce the cost per watt of producing photovoltaic devices. Inks have been developed for various materials, such as Ag, Cu, Ni and Al, which can be used to inkjet print metallizations for various kinds of photovoltaic devices. Use of these inks results in metallization with resistivities close to those of bulk materials. By means of inkjet printing a metallization grid can be printed with better resolution, i.e. smaller lines, than screen-printing. Also inks have been developed to deposit transparent conductive oxide films by means of ultrasonic spraying.

van Hest, M. F. A. M.; Curtis, C. J.; Miedaner, A.; Pasquarelli, R. M.; Kaydonova, T.; Hersh, P.; Ginley, D. S.

2008-05-01

356

The Observation of the Steady State Phase on Rolling Contact Using Finite Element Analysis  

NASA Astrophysics Data System (ADS)

The study of the mechanical components on the micro/nano-scale requires the investigation on stress, contact pressure and deformation of the contacting components particularly. On the micro/nano-scale, the discussion on the rolling contact between two mechanical components takes place not only on the general surface but also covers the asperity level on the rough surface scale. During rolling contact of the mechanical components, the model can be simplified to the contact between a roller on a rough surface. This model is occupied in finite element analysis to observe the steady state phase during rolling contact. The steady state phase is the second phase of the new components life-cycle where the plastic deformation, contact stress and contact pressure found their stabilized form and the optimal condition on the contact loading is reached. The steady state phase takes place after running-in phase where the aforementioned parameters still occur in the transient mode and still vary with time. In this paper, two-dimensional model of a cylinder rolls over a surface are employed in the simulation by considering the elastic-plastic material with strain hardening behavior. The contact stress and residual stress of the rough surface due to rolling contact are observed to determine the steady state phase. The results show that the steady state of the contact stress and residual stress has been obtained on the second repeated rolling contact. The stability of the contact and residual stress on the second cycle is not only influenced by the strain hardening behavior but it is also influenced by the flattening of the asperity which produces larger contact area such that the contact load is homogenously distributed on the truncated asperity.

Ismail, R.; Tauviqirrahman, M.; Jamari, Jamari; Schipper, D. J.

2011-12-01

357

Daidzin: a potent, selective inhibitor of human mitochondrial aldehyde dehydrogenase.  

PubMed Central

Human mitochondrial aldehyde dehydrogenase (ALDH-I) is potently, reversibly, and selectively inhibited by an isoflavone isolated from Radix puerariae and identified as daidzin, the 7-glucoside of 4',7-dihydroxyisoflavone. Kinetic analysis with formaldehyde as substrate reveals that daidzin inhibits ALDH-I competitively with respect to formaldehyde with a Ki of 40 nM, and uncompetitively with respect to the coenzyme NAD+. The human cytosolic aldehyde dehydrogenase isozyme (ALDH-II) is nearly 3 orders of magnitude less sensitive to daidzin inhibition. Daidzin does not inhibit human class I, II, or III alcohol dehydrogenases, nor does it have any significant effect on biological systems that are known to be affected by other isoflavones. Among more than 40 structurally related compounds surveyed, 12 inhibit ALDH-I, but only prunetin and 5-hydroxydaidzin (genistin) combine high selectivity and potency, although they are 7- to 15-fold less potent than daidzin. Structure-function relationships have established a basis for the design and synthesis of additional ALDH inhibitors that could both be yet more potent and specific.

Keung, W M; Vallee, B L

1993-01-01

358

Tetrahydrohyperforin and Octahydrohyperforin Are Two New Potent Inhibitors of Angiogenesis  

PubMed Central

Background We have previously shown that hyperforin, a phloroglucinol derivative found in St. John's wort, behaves as a potent anti-angiogenic compound. To identify the reactive group(s) mainly involved in this anti-angiogenic effect, we have investigated the anti-angiogenic properties of a series of stable derivatives obtained by oxidative modification of the natural product. In addition, in the present work we have studied the role of the four carbonyl groups present in hyperforin by investigating the potential of some other chemically stable derivatives. Methodology/Principal Findings The experimental procedures included the analysis of the effects of treatment of endothelial cells with these compounds in cell growth, cell viability, cell migration and zymographic assays, as well as the tube formation assay on Matrigel. Our study with hyperforin and eight derivatives shows that the enolized ?-dicarbonyl system contained in the structure of hyperforin has a dominant role in its antiangiogenic activity. On the other hand, two of the tested hyperforin derivatives, namely, tetrahydrohyperforin and octahydrohyperforin, behave as potent inhibitors of angiogenesis. Additional characterization of these compounds included a cell specificity study of their effects on cell growth, as well as the in vivo Matrigel plug assay. Conclusions/Significance These observations could be useful for the rational design and chemical synthesis of more effective hyperforin derivatives as anti-angiogenic drugs. Altogether, the results indicate that octahydrohyperforin is a more specific and slightly more potent antiangiogenic compound than hyperforin.

Martinez-Poveda, Beatriz; Verotta, Luisella; Bombardelli, Ezio; Quesada, Ana R.; Medina, Miguel Angel

2010-01-01

359

Potent thermogenic action of triiodothyroacetic acid in brown adipocytes.  

PubMed

Triiodothyroacetic acid (TRIAC) is a triiodothyronine (T3) metabolite with high affinity for T3 nuclear receptors. We compared the thermogenic action of TRIAC versus T3 in brown adipocytes, by studying target genes known to mediate thermogenic action: uncoupling protein 1 (UCP-1), a marker of brown adipocytes, and type II-5'deiodinase (D2), which provides the T3 required for thermogenesis. TRIAC is 10-50 times more potent than T3 at increasing the adrenergic induction of UCP-1 mRNA and D2 activities. TRIAC action on UCP-1 is exerted at the transcriptional level. In the presence of an adrenergic stimulus, TRIAC is also more potent than T3, inducing lipoprotein lipase mRNA and 5 deiodinase (D3) activity and mRNA. Maximal effects occur at very low concentrations (0.2 nM). The greater potency of TRIAC is not due to preferential cellular or nuclear uptake. Therefore, TRIAC is a potent thermogenic agent that might increase energy expenditure and regulate T3 production in brown adipocytes. PMID:14523556

Medina-Gomez, G; Hernàndez, A; Calvo, R-M; Martin, E; Obregón, M-J

2003-09-01

360

Tidal Forms  

NASA Astrophysics Data System (ADS)

We give an overview of some recent investigations on the mechanics of the processes whereby forms develop in tidal environments. The viewpoint taken here is mechanistic. Some of the questions which deserve an answer may be summarised as follows: i) do tidal channels tend to some altimetric long term equilibrium? ii) why are they typically convergent and weakly meandering? iii) how is such equilibrium affected by the hydrodynamics and morphodynamics of tidal inlets? iv) what is the hydrodynamic and morphodynamic role played by tidal flats adjacent to the channels? Some of the above questions have received a considerable attention in the last few years. Schuttelaars and de Swart (1996), Lanzoni and Seminara (2002) and, more recently, Bolla Pittaluga (2003) have investigated the first problem. In particular, the latter two contributions have shown that a straight tidal channel connected to a tidal sea at one end and closed at the other end tends to reach a long term equilibrium profile, which is slightly concave seaward and convex landward where a beach forms. The equilibrium profile is strongly sensitive to the harmonic content of the tidal forcing as well as to the value of sediment concentration established by the coastal hydrodynamics in the far field of the inlet region. Less important are the effect of channel convergence and the role of settling lag in the transport of suspended load. Insufficient attention has been devoted to the understanding of what mechanisms control channel convergence and meandering, though some similarities and differences between tidal and fluvial channels have emerged from some recent works. In particular, free bars form in tidal channels due to an instability mechanism essentially similar to that occurring under steady conditions though the oscillatory character of the flow field makes the bar pattern non migrating (Seminara and Tubino, 2001). Similarly, forced bars in curved tidal channels are driven by the development of centrifugally as well as topographically induced secondary flows, though the oscillatory character of the flow field makes the point bar pattern typical of tidal channels fairly symmetric (Solari et al., 2002, Solari and Toffolon, 2001). However, the detailed analysis of the planimetric pattern of tidal meanders performed by Marani et al. (2002) has shown that the often observed features of fluvial meanders which typically exhibit upstream skewing and downstream migration are both absent in tidal environments. The cause of such a behaviour as well as the weakly dynamic character of tidal meanders still awaits mechanistic explanations. The hydrodynamics of sharp tidal inlets is characterised by a strong asymmetry in the case of fixed beds (Blondeaux et al., 1982), displaying a nearly irrotational flow field in the flood phase and an unsteady jet in the ebb phase. The erodible character of the bed makes the asymmetry weaker due to the progressive excavation of a submerged channel (Tambroni et al., 2003a) which tends to constrain the flow direction also during the flood phase. The consequences of such feature on the exchange of sediments between the channel and the sea are currently being investigated. Finally, the presence of tidal flats has a significant effect on channel hydrodynamics which tends to attain an ebb dominant character as the role of the flats increases (Tambroni et al., 2003b). The morphodynamic effect of such novel feature as well as the exchange of sediments between channel and adjacent flats are also the subject of current investigations. Most of the theoretical results mentioned above have been substantiated through a set of experiments performed at the laboratory of the Department of Environmental Engineering of the University of Genova (Tambroni et al., 2003a). References Blondeaux, P., de Bernardinis, B. and Seminara, G. 1982. Correnti di marea in prossimita di imboccature e loro influenza sul ricambio lagunare. Atti XVIII Conv. Idraulica e Costruzioni Idrauliche, Bologna, 21-23 Settembre. Bolla Pittaluga, M. 2003. Long term morphodynamic equilibrium

Bolla Pittaluga, M.; Seminara, G.; Tambroni, N.

2003-04-01

361

Behavior of contact angles on rough solid surfaces  

NASA Astrophysics Data System (ADS)

In this study, we consider a sinusoidal surface and show explicitly how the pinning and depinning occur for a two dimensional liquid drop on such non-ideal surfaces as the volume of the drop is increased or decreased. The surface energy of the drop have a wave like form affected by solid surface shapes and contact lines are pinned by the energy barriers. We show that the contact angle hysteresis (CAH) emerges from this simple model even though we do not take any effect of viscous dissipation into account.

Yoshitake, Yumiko; Okumura, Ko

2010-11-01

362

Electrical Spin Injection from an Fe\\/AlGaAs Schottky Contact  

Microsoft Academic Search

We report electrical spin injection from a ferromagnetic Fe contact into an AlGaAs(n)\\/GaAs\\/AlGaAs(p)\\/GaAs(p) light emitting diode (LED) . The top Fe layer forms a Schottky tunnel barrier contact to the AlGaAs(n) layer. Spin polarized electrons are injected from the Fe contact while unpolarized holes are injected from the GaAs(p) buffer layer. The injected carriers recombine in the GaAs well and

G. Itskos; R. Mallory; G. Kioseoglou; A. Petrou; A. T. Hanbicki; B. T. Jonker

2002-01-01

363

Applying selective liquid-phase deposition to create contact holes in plasma damage-free process  

Microsoft Academic Search

We apply an alternative plasma damage-free process, selective liquid-phase deposition (S-LPD), instead of the conventional RIE to form metal\\/semiconductor contact holes. This paper studies the performance comparison between S-LPD and RIE for formation of contact holes in n+\\/p junction diodes, Schottky diodes, and ohmic contacts. In our experiments, if the plasma-free S-LPD technique is adopted, there is excellent performance, including

C.-F. Yeh; C.-H. Liu

1998-01-01

364

Comparing the relative benefits of grooming-contact and full-contact pairing for laboratory-housed adult female Macaca fascicularis.  

PubMed

Tactile social contact is the most effective form of environmental enrichment for promoting normal behavior in captive primates. For laboratory macaques housed indoors, pair housing is the most common method for socialization. Pairs can be housed either in full contact (FC), or in protected contact (PC). At Washington National Primate Research Center, PC is provided by grooming-contact (GC) cages whereby two partners are housed individually in adjacent cages with access to each other through widely spaced vertical bars. Grooming-contact has been used to accommodate research protocol restrictions and improve the likelihood of compatibility for various pairings, in part by enabling male-female pairs. This study compares the benefits between the two housing types by video recording 14 pairs of adult female Macaca fascicularis in four sequential housing phases following an ABBA design: baseline grooming-contact, full contact shortly after introduction, 1-month-later full contact, and after reversion to grooming-contact. Prior to this study, pairs had been housed compatibly in GC. Twelve of the 14 long-term pairs transitioned successfully to full contact and data presented exclude the two failed pairs. Allogrooming increased significantly when pairs first switched from GC to FC (P = 0.018), but the effect did not last through the on 1-month-later FC phase suggesting that the initial improvement in affiliative behavior was a transitory novelty response that did not persist. Self-grooming significantly decreased between the first GC and first FC phases (P = 0.016), likely due to redirected allogrooming. Non-contact affiliative behavior towards partner or other conspecifics in the room did not differ, nor did agonism towards partner or others in the room. Occurrence of abnormal, tension, manipulation, miscellaneous active, and inactive behaviors did not differ significantly across housing phases. Proximity measurements indicated that pairs were significantly out of arm's reach more often in protected contact than when in full contact (P ? 0.02). Proportion of time spent in physical contact significantly increased between the first GC and first FC phases (P = 0.002), but subsequently declined. For both FC phases, partners chose to spend about 50% of their time in the same cage. Few behavioral improvements were seen after pairs switched to full contact and no negative effects came of reversion to grooming contact. This study suggests that tactile contact provided through widely spaced bars (grooming-contact) is a viable alternative to full contact housing for adult female longtailed macaques. It provides a degree of social housing while allowing both partners choice and control, key concepts in contemporary animal welfare guidelines. PMID:22685366

Lee, Grace H; Thom, Jinhee P; Chu, Katherine L; Crockett, Carolyn M

2011-10-01

365

The effects of amount of contact, contact expectation, and contact experience with police on attitudes toward police  

Microsoft Academic Search

This study examined the relationship of amount of contact, contact expectation, and contact experience with attitudes toward\\u000a police. A telephone survey conducted in Midland and Odessa, Texas, was given to 581 individuals. Participants were asked questions\\u000a regarding their attitudes toward police. Participants who had contact with police in the last two years (n=258) were also asked about the amount and

Robert A. Bartsch; Sutham Cheurprakobkit

2004-01-01

366

78 FR 14549 - National Contact Center; Information Collection; National Contact Center Customer Evaluation Survey  

Federal Register 2010, 2011, 2012, 2013

...Control No. 3090-0278; Docket 2012-0001; Sequence 19] National Contact Center; Information Collection; National Contact Center Customer Evaluation Survey AGENCY: Contact Center Services, Federal Citizen Information Center, Office of...

2013-03-06

367

75 FR 6032 - National Contact Center; Submission for OMB Review; National Contact Center Customer Evaluation...  

Federal Register 2010, 2011, 2012, 2013

...OMB Control No. 3090-0278] National Contact Center; Submission for OMB Review; National Contact Center Customer Evaluation Survey AGENCY...collection requirement regarding the National Contact Center customer evaluation survey. A...

2010-02-05

368

78 FR 30303 - National Contact Center; Submission for OMB Review; National Contact Center Customer Evaluation...  

Federal Register 2010, 2011, 2012, 2013

...Control No. 3090-0278; Docket 2012-0001; Sequence 19] National Contact Center; Submission for OMB Review; National Contact Center Customer Evaluation Survey AGENCY: Contact Center Services, Federal Citizen Information Center, Office...

2013-05-22

369

How contact metamorphism can trigger global climate changes: Modeling gas generation around igneous sills in sedimentary basins  

NASA Astrophysics Data System (ADS)

Large volumes of greenhouse gases such as CH 4 and CO 2 form by contact metamorphism of organic-rich sediments in aureoles around sill intrusions in sedimentary basins. Thermogenic gas generation and dehydration reactions in shale are treated numerically in order to quantify basin-scale devolatilization. We show that aureole thicknesses, defined as the zone of elevated metamorphism relative to the background level, vary within 30-250% of the sill thickness, depending on the temperature of the host-rock and intrusion, besides the sill thickness. In shales with total organic carbon content of >5 wt.%, CH 4 is the dominant volatile (85-135 kg/m 3) generated through organic cracking, relative to H 2O-generation from dehydration reactions (30-110 kg/m 3). Even using conservative estimates of melt volumes, extrapolation of our results to the scale of sill complexes in a sedimentary basin indicates that devolatilization can have generated ˜2700-16200 Gt CH 4 in the Karoo Basin (South Africa), and ˜600-3500 Gt CH 4 in the Vøring and Møre basins (offshore Norway). The generation of volatiles is occurring on a time-scale of 10-1000 years within an aureole of a single sill, which makes the rate of sill emplacement the time-constraining factor on a basin-scale. This study demonstrates that thousands of gigatons of potent greenhouse gases like methane can be generated during emplacement of Large Igneous Provinces in sedimentary basins.

Aarnes, Ingrid; Svensen, Henrik; Connolly, James A. D.; Podladchikov, Yuri Y.

2010-12-01

370

Contact Binaries: The Current State  

NASA Astrophysics Data System (ADS)

Lucy's model of contact binaries has been serving well since its development in 1968 as an excellent conceptual framework for internal structure and evolution studies of the W UMa type stars. Its over-constrained structural demands were recognized early, but-from the observational point of view-it was particularly appealing in its ability to explain W UMa-type binary light curves. Large numbers of photometric light curves of W UMa type binaries have been solved for geometrical parameters utilizing the clarity and simplicity of Lucy's model to the point of frequent over-interpretation of the meager light-curve information content. Many, single, photometric solutions do not translate into a satisfactory understanding of these binaries. As the David Dunlap Observatory radial velocity program of bright, close binary stars (conducted in the last 10 years before the observatory closure in 2008) has shown, there are problems when spectroscopic results are confronted with light-curve solutions: Very frequently, the crucial parameter of the mass-ratio determined spectroscopically is entirely different from its photometric analogue (i.e. the one determined assuming a strict adherence to the Lucy's model), the third star incidence is high (which makes light curve solutions difficult, if not entirely wrong, even for totally eclipsing systems) and-last but not least-the model has serious difficulties for the best observed case of the crucially important, very low mass-ratio system AW UMa. One would argue that it is spectroscopy which gives correct results, but it requires access to large telescopes, extensive use of special techniques to analyze strongly blended and rotationally broadened spectra and is simply much harder to do than photometry. If the light curve solutions deceive us into believing in correctness of Lucy's contact-binary model and if only a fraction of (or none among) W UMa systems can be explained by that model, then the subject of contact binaries needs new ideas and new, mostly spectroscopic, high quality observations.

Rucinski, Slavek

2010-12-01

371

Nanocrystal-based Ohmic contacts on n and p-type germanium  

NASA Astrophysics Data System (ADS)

We report a simple method of forming Ohmic contacts to n and p-type germanium (Ge) simultaneously using Au nanocrystals embedded in Ti contact metal. The electric field due to the work-function difference of Ti and Au reduces the tunneling resistance at the Ti-Au/Ge interface for n and p-type contacts. The nanocrystal-based contacts on n-Ge exhibit quasi-Ohmic current-voltage characteristics with >1000× increase in current density and an apparent reduction of 0.18 eV in the barrier height over Ti/n-Ge and Au/n-Ge contacts that show rectifying characteristics due to Fermi level pinning. On n+-Ge, the nanocrystal-based contacts exhibit Ohmic characteristics with >35× reduction in zero-bias resistance over Ti/n+-Ge contacts. Similar to Ti and Au contacts on p-Ge, Au nanocrystals embedded in Ti continue to exhibit Ohmic characteristics. This is in contrast to methods that convert p-type contacts from Ohmic to rectifying in the process of forming an Ohmic contact on n-Ge by inserting a thin dielectric layer between the metal and Ge. Device simulations reinforce the observed decrease in tunneling resistance due to the enhanced electric field at the Ti-Au/Ge interface.

Pavan Kishore, V.; Paramahans, Prashanth; Sadana, Sunny; Ganguly, Udayan; Lodha, Saurabh

2012-04-01

372

The Effect of Contact Angle on Rolling-Contact Fatigue and Bearing Load Capacity  

Microsoft Academic Search

The NASA five-ball fatigue tester was used to determine the rolling-contact fatigue life of ½-in.-diameter M-1 steel balls applicable for high-temperature bearing use, and modified 204-size angular-contact ball bearings at various contact angles. For a constant Contact stress in the five-ball fatigue tester, fatigue life decreased with increasing contact angle. In contrast, relative thrust-load capacity increased with increasing contact angle.

Erwin V. Zaretsky; William J. Anderson; Richard J. Parker

1962-01-01

373

Gradient-index contact lens  

NASA Astrophysics Data System (ADS)

A gradient-index (GRIN) contact lens (CL) is proposed to decrease spherical aberration and to increase the diopter. A plastic radial GRIN rod was successfully obtained by using the vapor-phase diffusion copolymerization technique. The resulting index distribution of the GRIN rod was almost parabolic against the distance from the center axis, and the Delta n value was -0.030. The GRIN CL was prepared by grinding and polishing the rod. It is theoretically and experimentally concluded that using the radial GRIN material can significantly improve the optical properties of CL's.

Koike, Yasuhiro; Asakawa, Akihiko; Wu, Shang Pin; Nihei, Eisuke

1995-08-01

374

[Contact dermatitis caused by foods].  

PubMed

Cutaneous adverse reactions to foods and food additives are a growing public health problem which can occur both in the avocational and occupational settings. This article reviews different reaction patterns which can occur upon contact with foods and discusses some clinically important food-associated metal and fragrance allergens responsible for these adverse effects. As ultimately, education and guidance can minimize the morbidity of food allergy and enhance the quality of life of the affected individual; this article highlights this growing problem. PMID:17669298

Amado, A; Jacob, S E

2007-09-01

375

[Contact radiotherapy of rheumatoid arthritis].  

PubMed

The authors have devised a method of contact radiotherapy with open radionuclides (198Au) to be used in the treatment of patients suffering from rheumatoid arthritis. Indications for therapy have been defined. In 360 patients suffering from rheumatoid arthritis, radioactive colloid gold was administered to the affected joints. The therapeutic effect was slow in development. The best clinical results were recorded at month 12. Considerable improvement was noticed in 70% of the patients, improvement in 20%, and in 10% of the patients, no therapeutic effect could be recorded. Good effect was ascertained in patients with X-ray Stage I and II disease (70%). PMID:1284418

Tsyb, A F; Drozdovski?, B Ia; Ikonnikov, A I

1992-01-01

376

Clean Cities Program Contacts (Fact Sheet)  

SciTech Connect

This fact sheet provides contact information for program staff of the U.S. Department of Energy's Clean Cities program, as well as contact information for the nearly 100 local Clean Cities coalitions across the country.

Not Available

2012-03-01

377

Environmental Decision Memo for Food Contact Notification ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... Environmental Decision Memo for Food Contact Notification No. ... 1268. FINDING OF NO SIGNIFICANT IMPACT. A food-contact notification (FCN No. ... More results from www.fda.gov/food/ingredientspackaginglabeling/environmentaldecisions

378

SOPP 8104: Documentation of Telephone Contacts with ...  

Center for Biologics Evaluation and Research (CBER)

... initial point of contact for industry representatives requesting filing requirements, application status, or the appropriate contact for a technical issue. ... More results from www.fda.gov/biologicsbloodvaccines/guidancecomplianceregulatoryinformation/proceduressopps

379

Modeling of Rapid Direct Contact Condensation.  

National Technical Information Service (NTIS)

The focus of the study is on rapid direct-contact condensation phenomena, that is, direct contact condensation situations characterized by extremely high condensation rates and violent mixing at the liquid-vapor interface. Rapid condensation phenomena ari...

G. B. Wallis H. J. Richter J. A. Valenzuela P. H. Rothe

1985-01-01

380

Environmental Decision Memo for Food Contact Notification ...  

Center for Food Safety and Applied Nutrition (CFSAN)

Polyglycolic acid as a nonfood-contact layer of multi-layer polyethylene terephthalate or polylactic acid food-contact articles or as a component ... More results from www.fda.gov/food/ingredientspackaginglabeling/environmentaldecisions

381

Potent aminocyclitol glucocerebrosidase inhibitors are subnanomolar pharmacological chaperones for treating gaucher disease.  

PubMed

Amino-myo-inositol derivatives have been found to be potent inhibitors of glucocerebrosidase (GCase), the ?-glucosidase enzyme deficient in Gaucher disease (GD). When tested using lymphoblasts derived from patients with GD homozygous for N370S or L444P mutations, the compounds enhanced GCase activity at very low concentrations. The most potent inhibitor, (1R,2S,3R,4S,5S,6R)-5-(nonylamino)-6-(nonyloxy)cyclohexane-1,2,3,4-tetraol had a K(i) of 1 nM using isolated enzyme and an IC(50) of 4.3 nM when assayed in human fibroblast cell culture. This aminocyclitol produced maximum increases of GCase activities of 90% in N370S lymphoblasts at 1 nM and 40% in L444P at 0.01 nM following a three-day incubation. In addition to inhibitory potency, this compound has the permeability, subcellular distribution, and cell metabolism characteristics that are important for use as a pharmacological chaperone. It is a remarkable finding that picomolar concentrations of aminocyclitols are sufficient to enhance activity in the L444P variant, which produces a severe neuronopathic form of GD without clinical treatment. PMID:22512696

Trapero, Ana; González-Bulnes, Patricia; Butters, Terry D; Llebaria, Amadeu

2012-05-01

382

Air oxidation of d-limonene (the citrus solvent) creates potent allergens.  

PubMed

Products containing as much as 95% of d-limonene are used for, e.g., degreasing metal before industrial painting and for cleaning assemblies. Experimental studies on the sensitizing potential of limonene show diverging results. In a previous study, we found that the sensitizing potential of d-limonene increased with prolonged air exposure. The aim of this study was to make further chemical analyses, to identify compounds formed by air exposure of d-limonene and to study their allergenic potential. d-limonene was found to be a sensitizer after prolonged exposure to air according to 2 Freund's complete adjuvant test (FCAT) experiments and 1 guinea pig maximization test (GPMT) study. No significant response was obtained to d-limonene not air exposed, even if the animals were sensitized to oxidized d-limonene. 5 main oxidation products of d-limonene were identified. (R)-(-)-carvone and a mixture of cis and trans isomers of (+)-limonene oxide were found to be potent sensitizers, while no significant reactions were obtained in the animals induced with a mixture of cis and trans isomers of (-)-carveol. It can be concluded that air oxidation of d-limonene is essential for its sensitizing potential, and that potent allergens are created. PMID:1395597

Karlberg, A T; Magnusson, K; Nilsson, U

1992-05-01

383

Contact Pressure Measurement System in Cross Wedge Rolling  

NASA Astrophysics Data System (ADS)

In the cross wedge rolling process (CWR), plastic deformation is geared by a driving torque transmitted by friction on die surface. Friction plays a role which has to be further identified in this metal forming process. The local contact pressure between a cylindrical billet and flat dies seems to be a relevant parameter to characterize the severe contact conditions during the rolling. This paper deals with an experimental measurement technology, which has been designed and implemented on a semi-industrial CWR test bench with plate configuration. This measurement system using pin and piezoelectric sensor is presented, with an analysis of the system operation and design detail. Characterization of systematic error and calibration tests are then explained. Additional tests performed on hot steel preforms allow to check the ability of the contact pressure measurement system to resist under severe operating conditions. Realistic results for varying temperatures are then discussed.

Mangin, Philippe; Langlois, Laurent; Bigot, Régis

2011-01-01

384

In-office microwave disinfection of soft contact lenses  

SciTech Connect

We evaluated the effectiveness of an in-office microwave disinfection procedure which allowed for the disinfection of up to 40 soft contact lenses at one time. Ciba AOSept cases filled with sterile unpreserved saline were contaminated with one of six FDA test challenge microorganisms at a concentration of approximately 10(3) colony forming units per milliliter (CFU/ml). Twenty cases were placed on the rotating plate of a standard 2450 MHz 650 W microwave oven in a 10-cm diameter circle. The cases were exposed to high intensity microwave irradiation for periods of 0 to 15 min. None of the 6 microorganisms evaluated survived 2 min or longer of microwave exposure. Our findings indicated that microwave irradiation can be a convenient, rapid, and effective method of disinfecting a number of soft contact lenses at one time and thus adaptable as an in-office soft contact lens disinfection procedure.

Harris, M.G.; Rechberger, J.; Grant, T.; Holden, B.A. (Univ. of California School of Optometry, Berkeley (USA))

1990-02-01

385

Bacterial interactions with contact lenses; effects of lens material, lens wear and microbial physiology  

Microsoft Academic Search

Contact lens wear is a successful form of vision correction. However, adverse responses can occur during wear. Many of these adverse responses are produced as a consequence of bacterial colonization of the lens. The present study demonstrated that during asymptomatic contact lens wear lenses are colonized by low levels of bacteria with gram-positive bacteria, such as coagulase negative staphylococci, predominating.

M. D. P Willcox; N Harmis; B. A Cowell; T Williams; B. A Holden

2001-01-01

386

Arc erosion tests and study of surface of Ag-WC contacts after arc switching operations  

Microsoft Academic Search

This work presents investigation results of surface structures formed on contacts made of Ag-WC composite materials during arc operation on breaking currents 6 kA. The contacts were made using the method of sintering compacts from mixtures of Ag and WC powders. Electrical tests were carried out under standardized conditions. In the paper, the results of SEM investigations are presented for

K. Kaliszuk; K. Frydman; D. Wojcik-Grzybek; W. Bucholc; E. Walczuk; P. Borkowski; D. Zasada

2004-01-01

387

Using Contact Work in Interactions with Adults with Learning Disabilities and Autistic Spectrum Disorders  

ERIC Educational Resources Information Center

|This article describes a project about using contact work with people with learning disabilities and autistic spectrum disorder. People with learning disabilities and additional autistic spectrum disorder are at risk of becoming socially isolated because of their difficulties in interacting with others. Contact work is a form of Pre-Therapy,…

Brooks, Sharon; Paterson, Gail

2011-01-01

388

The Russians Are Coming, the Russians are Dead: Myth and Historical Consciousness in Two Contact Narratives.  

ERIC Educational Resources Information Center

|This research paper examines hidden cultural patterns establishing the expression of historical thought in Native Alaskan narratives which describe first contact with Russians. Historical consciousness in oral contact stories is always mythic in form, as well as in content. Native American oral cultures understood new events by "troping," or…

Ruppert, James

389

The coefficient of proportionality ? between real contact area and load, with new asperity models  

Microsoft Academic Search

Most recent numerical works on fractal surfaces have simply compared the low load limit of the coefficient of proportionality ? of the relationship between real contact area and load. In particular, that provided by Persson's theory, and that obtained from the Bush, Gibson and Thomas (BGT-A) asperity contact theory, which is a generalized form of the Greenwood and Williamson (GW)

Marco Paggi; Michele Ciavarella

2010-01-01

390

Rolling Contact Fatigue of Ceramics  

SciTech Connect

High hardness, low coefficient of thermal expansion and high temperature capability are properties also suited to rolling element materials. Silicon nitride (Si{sub 3}N{sub 4}) has been found to have a good combination of properties suitable for these applications. However, much is still not known about rolling contact fatigue (RCF) behavior, which is fundamental information to assess the lifetime of the material. Additionally, there are several test techniques that are employed internationally whose measured RCF performances are often irreconcilable. Due to the lack of such information, some concern for the reliability of ceramic bearings still remains. This report surveys a variety of topics pertaining to RCF. Surface defects (cracks) in Si{sub 3}N{sub 4} and their propagation during RCF are discussed. Five methods to measure RCF are then briefly overviewed. Spalling, delamination, and rolling contact wear are discussed. Lastly, methods to destructively (e.g., C-sphere flexure strength testing) and non-destructively identify potential RCF-limiting flaws in Si{sub 3}N{sub 4} balls are described.

Wereszczak, Andrew A [ORNL; Wang, W. [Bournemouth University, Bournemouth, United Kingdom; Wang, Y. [Bournemouth University, Bournemouth, United Kingdom; Hadfield, M. [Bournemouth University, Bournemouth, United Kingdom; Kanematsu, W. [National Institute of Advanced Industrial Science and Technology, Japan; Kirkland, Timothy Philip [ORNL; Jadaan, Osama M. [University of Wisconsin, Platteville

2006-09-01

391

Do contacts make a difference?  

Microsoft Academic Search

This article examines the effects of mainstreaming on the attitudes of non-disabled students, in a secondary school, toward people with disabilities. Responses from 389 Form 1 and Form 2 students were analyzed. A 47-item Students’ Attitudes toward People with a Disability Scale was used to measure student attitudes at the beginning and end of the school year. The effect of

Donna Kam Pun Wong

2008-01-01

392

Increased formation of the potent oxidant peroxynitrite in the airways of asthmatic patients is associated with induction of nitric oxide synthase: effect of inhaled glucocorticoid  

Microsoft Academic Search

Peroxynitrite is a potent oxidant formed by the rapid reaction of the free radicals ni- tric oxide (NO) and superoxide. It causes airway hy- perresponsiveness and airway epithelial damage, en- hances inflammatory cell recruitment, and inhibits pulmonary surfactant. Asthma is characterized by in- creased airway hyperresponsiveness, airway epithelial shedding, and inflammation. We examined the pro- duction of peroxynitrite and the

DINA SALEH; PIERRE ERNST; SAM LIM; PETER J. BARNES; ADEL GIAID

393

Occupational issues of allergic contact dermatitis  

Microsoft Academic Search

Occupational contact dermatitis is often of multifactorial origin, and it is difficult to determine the relative significance of the various contributing factors. Contact allergies are relevant in 20–50% of recognised occupational contact dermatitis cases. The reported frequency in different studies varies, depending on differences in how occupational diseases are notified and recognised, in types of occupation in a geographical area,

Klaus E. Andersen

2003-01-01

394

Contact conformers in crystals of coordination compounds  

Microsoft Academic Search

In a continuation of the systematic study of contact conformers (coexisting molecules having different structures), a comparison of the structures of symmetrically independent molecules inthe crystals of 37 coordination compounds have been compared. Fourteen cases of contact conformers have been detected and systematized. The earlier suggestion that contact conformers are more typical of crystals of coordination compounds than of organic

E. É. Lavut; P. M. Zorkii; N. Yu. Chernikova

1982-01-01

395

Dynamic contact angles in CFD simulations  

Microsoft Academic Search

The accurate modelling of contact angle properties plays an important role in the simulation of free-surface micro flows. Taking capillary filling as an example, we first discuss the analytical solutions of a corresponding 1D description in certain limits and then derive an approximate analytical expression for the general case with constant contact angle. In case of a dynamic contact angle

Friedhelm Schönfeld; Steffen Hardt

2009-01-01

396

Contact Resistance Characteristics at Low Temperature  

Microsoft Academic Search

The application of cryogenics to the fields of electrical engineering has great possibility. However, performance of contacts used in the application may be estimated to deteriorate due to contaminant films. It is important subject to clarify the electrical conduction mechanisms of contacts covered with contamination films to obtain low contact resistance characteristics at the low temperature as well as at

TERUTAKA TAMAI; KINYA TSUCHIYA

1978-01-01

397

Contact stability for two-fingered grasps  

Microsoft Academic Search

Abstract We distinguish between two types of grasp stability, which we call spatial grasp stability and contact grasp stability. We show via examples that spatial stability cannot capture certain intuitive concepts of grasp stability and hence that any full understanding of grasp stability must include contact stability. We derive a model of how the positions of the points of contact

D. j. Montana

1992-01-01

398

Optimization techniques for contact stress analysis  

Microsoft Academic Search

The analysis of stresses induced by contact between two bodies is inherently difficult because the size of the contact zone is unknown and constantly changing throughout loading. To overcome these difficulties, two approximation methods have been developed to determine the magnitude of contact stresses using the Rayleigh-Ritz method and the finite element method. Numerical optimization methods are employed to solve

Eric S. McDonald

1992-01-01

399

Multibody Dynamic Simulation of Knee Contact Mechanics  

Microsoft Academic Search

Multibody dynamic musculoskeletal models capable of predicting muscle forces and joint contact pressures simultaneously would be valuable for studying clinical issues related to knee joint degeneration and restoration. Current three-dimensional multi- body knee models are either quasi-static with deformable contact or dynamic with rigid contact. This study proposes a computa- tionally efficient methodology for combining multibody dynamic simulation methods with

Yanhong Bei; Benjamin J. Fregly

400

Allergic contact dermatitis to plastic banknotes.  

PubMed

Allergic contact dermatitis to ultraviolet (UV) cured acrylates occurs predominantly in occupationally exposed workers. Two men presented with dermatitis coinciding with the location of banknotes in their pockets. Patch testing confirmed allergic contact dermatitis to multiple acrylates and Australian plastic banknotes. This is the first report of contact allergy to acrylates present in Australian plastic banknotes. PMID:10439531

Mohamed, M; Delaney, T A; Horton, J J

1999-08-01

401

Contacts Between Police and the Public, 2005.  

National Technical Information Service (NTIS)

An estimated 19% of U.S. residents age 16 or older had a face-to-face contact with a police officer in 2005, a decrease from 21% of residents who had contact with police in 2002. Contact between police and the public was more common among males, whites, a...

E. L. Smith M. R. Durose P. A. Langan

2007-01-01

402

Contact lens fitting in high degree myopia  

Microsoft Academic Search

Advantages and disadvantages of both spectacle and contact lens correction of high degree myopia are reviewed. Pertinent aftercare problems in this group of patients are discussed. Aspects of contact lens wear with regard to the eyelids are described. Soft contact lens problems are discussed in relation to the greater thickness of lenses of high power. Guidelines are provided for the

Christine L. K. Astin

1999-01-01

403

A novel automated method to measure total antioxidant response against potent free radical reactions  

Microsoft Academic Search

Objectives: Oxidative damage of biomolecules occurs as a result of potent free radical reactions. In this study, a novel, colorimetric and fully automated method for measuring total antioxidant response (TAR) against potent free radical reactions is described.Design and methods: Potent free radical reactions were initiated with the production of hydroxyl radical (OH) via Fenton reaction, and the rate of the

Ozcan Erel

2004-01-01

404

Contacting surfaces; A problem in fatigue and diffusion bonding  

SciTech Connect

Contact between surfaces usually occurs at asperities under compression or at connecting ligaments, depending on how the interface is formed. This paper deals with the nondestructive evaluation of the topology of contact and with the use of this information to predict the effects that loads borne by these contacts have on mechanical properties. Two specific examples are discussed: a fatigue crack and a diffusion bond. Asperity contact along the fracture surface of a fatigue crack partially shields the crack tip from the externally applied driving force. Using information from acoustic experiments, the geometry of the asperities, the contacting stress, and the shielding stress intensity factor have been estimated. Acoustically, a diffusion bonded interface looks very similar to that joining the two sides of a partially closed crack. In this particular case, the acoustically determined geometry of well-bonded ligaments can be verified by fractography of destructively tested samples whose bond strength has also been determined. Models to determine the bond strength from the ligament geometry are suggested.

Buck, O.; Thompson, R.B.; Rehbein, D.K.; Brasche, L.J.H. (Ames Lab., IA (USA)); Palmer, D.D. (Burns and McDonnell Engineering Co., Kansas City, MO (USA))

1989-04-01

405

Direct measurement of friction of a fluctuating contact line  

NASA Astrophysics Data System (ADS)

What happens at a moving contact line, where one fluid displaces another (immiscible) fluid over a solid surface, is a fundamental issue in fluid dynamics. In this presentation, we report a direct measurement of the friction coefficient in the immediate vicinity of a fluctuating contact line using a micron-sized vertical glass fiber with one end glued to an atomic force microscope (AFM) cantilever beam and the other end touching a liquid-air interface. By measuring the broadening of the resonance peak of the cantilever system with varying liquid viscosity ?, we obtain the friction coefficient ?c associated with the contact line fluctuations on the glass fiber of diameter d and find it has the universal form, ?c= 0.8?d?, independent of the contact angle. The result is further confirmed by using a soap film system whose bulk effect is negligibly small. This is the first time that the friction coefficient of a fluctuating contact line is measured. *Work supported by the Research Grants Council of Hong Kong SAR.

Guo, Shuo; Gao, Min; Xiong, Xiaomin; Wang, Yong Jian; Wang, Xiaoping; Sheng, Ping; Tong, Penger

2013-03-01

406

Collective and single cell behavior in epithelial contact inhibition  

PubMed Central

Control of cell proliferation is a fundamental aspect of tissue physiology central to morphogenesis, wound healing, and cancer. Although many of the molecular genetic factors are now known, the system level regulation of growth is still poorly understood. A simple form of inhibition of cell proliferation is encountered in vitro in normally differentiating epithelial cell cultures and is known as “contact inhibition.” The study presented here provides a quantitative characterization of contact inhibition dynamics on tissue-wide and single cell levels. Using long-term tracking of cultured Madin-Darby canine kidney cells we demonstrate that inhibition of cell division in a confluent monolayer follows inhibition of cell motility and sets in when mechanical constraint on local expansion causes divisions to reduce cell area. We quantify cell motility and cell cycle statistics in the low density confluent regime and their change across the transition to epithelial morphology which occurs with increasing cell density. We then study the dynamics of cell area distribution arising through reductive division, determine the average mitotic rate as a function of cell size, and demonstrate that complete arrest of mitosis occurs when cell area falls below a critical value. We also present a simple computational model of growth mechanics which captures all aspects of the observed behavior. Our measurements and analysis show that contact inhibition is a consequence of mechanical interaction and constraint rather than interfacial contact alone, and define quantitative phenotypes that can guide future studies of molecular mechanisms underlying contact inhibition.

Puliafito, Alberto; Hufnagel, Lars; Neveu, Pierre; Streichan, Sebastian; Sigal, Alex; Fygenson, D. Kuchnir; Shraiman, Boris I.

2012-01-01

407

Discovery of Tertiary Sulfonamides as Potent Liver X Receptor Antagonists  

SciTech Connect

Tertiary sulfonamides were identified in a HTS as dual liver X receptor (LXR, NR1H2, and NR1H3) ligands, and the binding affinity of the series was increased through iterative analogue synthesis. A ligand-bound cocrystal structure was determined which elucidated key interactions for high binding affinity. Further characterization of the tertiary sulfonamide series led to the identification of high affinity LXR antagonists. GSK2033 (17) is the first potent cell-active LXR antagonist described to date. 17 may be a useful chemical probe to explore the cell biology of this orphan nuclear receptor.

Zuercher, William J.; Buckholz† , Richard G.; Campobasso, Nino; Collins, Jon L.; Galardi, Cristin M.; Gampe, Robert T.; Hyatt, Stephen M.; Merrihew, Susan L.; Moore, John T.; Oplinger, Jeffrey A.; Reid, Paul R.; Spearing, Paul K.; Stanley, Thomas B.; Stewart, Eugene L.; Willson, Timothy M. (GSKNC)

2010-08-12

408

Design and synthesis of a potent histone deacetylase inhibitor.  

PubMed

Histone deacetylase (HDAC) inhibitors have potential for cancer therapy. An HDAC inhibitor based on a cyclic peptide mimic of known structure, linked by an aliphatic chain to a hydroxamic acid, was designed and synthesized. The chimeric compound showed potent competitive inhibition of nuclear HDACs, with an IC50 value of 46 nM and a Ki value of 13.7 nM. The designed inhibitor showed 4-fold selectivity for HDAC1 (57 nM) over HDAC8 (231 nM). PMID:17419603

Liu, Tao; Kapustin, Galina; Etzkorn, Felicia A

2007-04-10

409

Pyrazolopyridines as potent PDE4B inhibitors: 5-Heterocycle SAR  

SciTech Connect

Following the discovery of 4-(substituted amino)-1-alkyl-pyrazolo[3,4-b]pyridine-5-carboxamides as potent and selective phosphodiesterase 4B inhibitors, [Hamblin, J. N.; Angell, T.; Ballentine, S., et al. Bioorg. Med. Chem. Lett.2008, 18, 4237] the SAR of the 5-position was investigated further. A range of substituted heterocycles showed good potencies against PDE4. Optimisation using X-ray crystallography and computational modelling led to the discovery of 16, with sub-nM inhibition of LPS-induced TNF-{alpha} production from isolated human peripheral blood mononuclear cells.

Mitchell, Charlotte J.; Ballantine, Stuart P.; Coe, Diane M.; Cook, Caroline M.; Delves, Christopher J.; Dowle, Mike D.; Edlin, Chris D.; Hamblin, J. Nicole; Holman, Stuart; Johnson, Martin R.; Jones, Paul S.; Keeling, Sue E.; Kranz, Michael; Lindvall, Mika; Lucas, Fiona S.; Neu, Margarete; Solanke, Yemisi E.; Somers, Don O.; Trivedi, Naimisha A.; Wiseman, Joanne O. (GSK)

2012-05-03

410

Methotrexate Is Highly Potent Against Pyrimethamine-Resistant Plasmodium vivax  

PubMed Central

Resistance of vivax malaria to treatment with antifolates, such as pyrimethamine (Pyr), is spreading as mutations in the dihydrofolatereductase (dhfr) genes are selected and disseminated. We tested the antitumor drug methotrexate (MTX), a potent competitive inhibitor of dhfr, against 11 Plasmodium vivax isolates ex vivo, 10 of which had multiple dhfr mutations associated with Pyr resistance. Despite high-grade resistance to Pyr (median 50% inhibitory concentration [IC50], 13,345 nM), these parasites were all highly susceptible to MTX (median IC50, 2.6 nM). Given its potency against Pyr-resistant P. vivax, the antimalarial potential of MTX deserves further investigation.

Imwong, Mallika; Suwanarusk, Rossarin; Nzila, Alexis; Leimanis, Mara L.; Sriprawat, Kanlaya; Kaewpongsri, Supaporn; Phyo, Aung Pyae; Snounou, Georges; Nosten, Francois; Renia, Laurent

2011-01-01

411

Use of highly potent bisphosphonates in the treatment of osteoporosis.  

PubMed

Bisphosphonates are effective inhibitors of bone remodeling. In the clinical setting, these agents prevent bone loss, preserve bone architecture, and improve bone strength. Clinically significant reduction in the risk of spine and nonspine fractures is observed in patients known to be at risk for fracture. When administered appropriately, these drugs are well tolerated and have an excellent safety profile. Potent bisphosphonates are now the preferred treatment option to reduce the fracture risk in men and women with involutional and glucocorticoid-induced osteoporosis. PMID:16036074

McClung, Michael

2003-12-01

412

Nonsteroidal compounds designed to mimic potent steroid sulfatase inhibitors  

Microsoft Academic Search

Chemical synthesis and enzyme inhibition results are reported for a series of nonsteroidal sulfatase inhibitors, 1-(p-sulfamoyloxyphenyl)-5-(p-t-butylbenzyl)-5-alkanols and the lower active phenolic analogues. These compounds conserve some structural elements from the previously reported potent steroidal inhibitor 3-O-sulfamate-17?-(p-t-butylbenzyl)-17?-hydroxy-estra-1,3,5(10)-triene, while the C18-methyl group and the hydrocarbon backbone represented by the steroid rings B, C, and D were replaced with a free conformational chain.

Liviu Constantin Ciobanu; Van Luu-The; Donald Poirier

2002-01-01

413

Antiangiogenic properties of fasudil, a potent Rho-Kinase inhibitor  

Microsoft Academic Search

Purpose  Vascular endothelial growth factor (VEGF) plays a pivotal role in pathological angiogenesis. In this study, we addressed the\\u000a therapeutic potential of fasudil, a potent Rho-kinase inhibitor, for VEGF-elicited angiogenesis and also for the intracellular\\u000a signalings induced by VEGF.\\u000a \\u000a \\u000a \\u000a Methods  In vitro, the inhibitory effects of fasudil on the VEGF-dependent VEGF receptor 2 (VEFGR2 or KDR), extracellular signal-related\\u000a kinase (ERK) 1\\/2, Akt

Yasuaki Hata; Muneki Miura; Shintaro Nakao; Shuhei Kawahara; Takeshi Kita; Tatsuro Ishibashi

2008-01-01

414

New potent calcimimetics: II. Discovery of benzothiazole trisubstituted ureas.  

PubMed

Following the identification of trisubstituted ureas as a promising new chemical series of allosteric modulators of the calcium sensing receptor (CaSR), we further explored the SAR around the urea substitution, leading to the discovery of benzothiazole urea compound 13. This compound is a potent calcimimetic with an EC50=20 nM (luciferase assay). Evaluated in an in vivo model of chronic renal failure (short term and long term in 5/6 nephrectomized rats), benzothiazole urea 13 significantly decreased PTH levels after oral administration while keeping calcemia within the normal range. PMID:23499504

Deprez, Pierre; Temal, Taoues; Jary, Hélène; Auberval, Marielle; Lively, Sarah; Guédin, Denis; Vevert, Jean-Paul

2013-02-08

415

Enantioselective Synthesis of (-)-Jiadifenin, a Potent Neurotrophic Modulator  

PubMed Central

The first enantioselective synthesis of (?)-jiadifenin (1), a potent neurite outgrowth promoter isolated from Illicium species, is described. The synthetic strategy builds upon bicyclic motif 6 that represents the AB ring of the natural product and proceeds in 19 steps and 1.1% overall yield. Key to our approach is a Mn(III)-mediated oxidation reaction of A ring that, following a regio- and diastereoselective ?-hydroxylation and methylation sequence, produces the desired functionalities of (?)-jiadifenin. The effect of synthetic 1 in NGF-mediated neurite outgrowth was also measured in PC-12 cells.

Trzoss, Lynnie; Xu, Jing; Lacoske, Michelle H.; Mobley, William C.; Theodorakis, Emmanuel A.

2011-01-01

416

Fluoxetine Is a Potent Inhibitor of Coxsackievirus Replication  

PubMed Central

No antiviral drugs currently exist for the treatment of enterovirus infections, which are often severe and potentially life threatening. Molecular screening of small molecule libraries identified fluoxetine, a selective serotonin reuptake inhibitor, as a potent inhibitor of coxsackievirus replication. Fluoxetine did not interfere with either viral entry or translation of the viral genome. Instead, fluoxetine and its metabolite norfluoxetine markedly reduced the synthesis of viral RNA and protein. In view of its favorable pharmacokinetics and safety profile, fluoxetine warrants additional study as a potential antiviral agent for enterovirus infections.

Zuo, Jun; Quinn, Kevin K.; Kye, Steve; Cooper, Paige; Damoiseaux, Robert

2012-01-01

417

Novel potent selective phenylglycine antagonists of metabotropic glutamate receptors  

Microsoft Academic Search

The metabotropic glutamate (mGlu) receptor antagonist properties of novel phenylglycine analogues were investigated in adult rat cortical slices (mGlu receptors negatively coupled to adenylyl cyclase), neonatal rat cortical slices and in cultured rat cerebellar granule cells (mGlu receptors coupled to phosphoinositide hydrolysis). (RS)-?-methyl-4-phosphonophenylglycine (MPPG), (RS)-?-methyl-4-sulphonophenylglycine (MSPG), (RS)-?-methyl-4-tetrazolylphenylglycine (MTPG), (RS)-?-methyl-3-carboxymethyl-4-hydroxyphenylglycine (M3CM4HPG) and (RS)-?-methyl-4-hydroxy-3-phosphonomethylphenylglycine (M4H3PMPG) were demonstrated to have potent and selective

Jennifer S. Bedingfield; David E. Jane; Martyn C. Kemp; Nicholas J. Toms; Peter J. Roberts

1996-01-01

418

Biochemical Studies of the Lagunamides, Potent Cytotoxic Cyclic Depsipeptides from the Marine Cyanobacterium Lyngbya majuscula  

PubMed Central

Lagunamides A (1) and B (2) are potent cytotoxic cyclic depsipeptides isolated from the filamentous marine cyanobacterium, Lyngbya majuscula, from Pulau Hantu, Singapore. These compounds are structurally related to the aurilide-class of molecules, which have been reported to possess exquisite antiproliferative activities against cancer cells. The present study presents preliminary findings on the selectivity of lagunamides against various cancer cell lines as well as their mechanism of action by studying their effects on programmed cell death or apoptosis. Lagunamide A exhibited a selective growth inhibitory activity against a panel of cancer cell lines, including P388, A549, PC3, HCT8, and SK-OV3 cells, with IC50 values ranging from 1.6 nM to 6.4 nM. Morphological studies showed blebbing at the surface of cancer cells as well as cell shrinkage accompanied by loss of contact with the substratum and neighboring cells. Biochemical studies using HCT8 and MCF7 cancer cells suggested that the cytotoxic effect of 1 and 2 might act via induction of mitochondrial mediated apoptosis. Data presented in this study warrants further investigation on the mode of action and underscores the importance of the lagunamides as potential anticancer agents.

Tripathi, Ashootosh; Fang, Wanru; Leong, David Tai; Tan, Lik Tong

2012-01-01

419

Potent Inhibitors of Plasmodium Phospholipid Metabolism with a Broad Spectrum of In Vitro Antimalarial Activities  

PubMed Central

We characterized the potent in vitro antimalarial activity and biologic assessment of 13 phospholipid polar head analogs on a comparative basis. There was a positive relationship between the abilities of the drugs to inhibit parasite growth in culture and their abilities to specifically inhibit phosphatidylcholine biosynthesis of Plasmodium falciparum-infected erythrocytes. Maximal activity of G25 was observed for the trophozoite stage of the 48-h erythrocytic cycle (50% inhibitory concentration, 0.75 nM), whereas the schizont and ring stages were 12- and 213-fold less susceptible. The compounds exerted a rapid nonreversible cytotoxic effect, with complete clearance of parasitemia after 5 h of contact with the mature stages. The compounds were highly specific against P. falciparum, with much lower toxicity against three other mammalian cell lines, and the in vitro therapeutic indices ranged from 300 to 2,500,000. Finally, the monoquaternary ammonium E10 and two bis-ammonium salts, G5 and G25, were similarly active against multiresistant strains and fresh isolates of P. falciparum. This impressive selective in vitro toxicity against P. falciparum strongly highlights the clinical potential of these quaternary ammonium salts for malarial chemotherapy.

Ancelin, Marie L.; Calas, Michele; Vidal-Sailhan, Valerie; Herbute, Serge; Ringwald, Pascal; Vial, Henri J.

2003-01-01

420

Insitu TEM observation of controlled gold contact failure under electric bias  

NASA Astrophysics Data System (ADS)

We directly observed the gradual thinning and eventual failure of single-crystalline gold (Au) contacts under increasing electric bias. The contacts fractured in a controlled manner at a current density of around (2-3) × 1010 A/cm2, so that nanogaps 1-2 nm wide were formed reproducibly. Also, the surface migration of Au atoms was observed to be enhanced by stretching the contact, suggesting that the surface migration of the Au atoms was sensitive to the stress distribution. The Au contact is probably fractured in a controlled manner, when it becomes stress free.

Oshima, Yoshifumi; Kurui, Yoshihiko

2013-02-01

421

Improvement of Electrical Contact Reliability by Conductive Polymer Coated Elastomer Structure in Woven Electronic Textiles  

NASA Astrophysics Data System (ADS)

This article presents an improvement in the stability and durability of the electrical contacts employed in flexible devices. A coating of poly(3,4-ethylenedioxythiophene): poly(4-styrenesulfonate) in form of a solid conductive layer on a silicone elastomer structure is employed in creating an electrical circuit embedded into the fabric of a woven electronic textile, where the coating serves as an electrical contact between weft and warp ribbons. When the contact load increases to 1 mN, then, due to the flexibility of the structure, an electric current begins to flow through the circuit. The structure can sextuplicate the life of the electrical contact.

Yamashita, Takahiro; Takamatsu, Seiichi; Miyake, Koji; Itoh, Toshihiro

2012-12-01

422

In situ studies of interfacial contact evolution via a two-axis deflecting cantilever microinstrument  

NASA Astrophysics Data System (ADS)

The time-dependent assessment of two contacting polycrystalline silicon surfaces is realized using a microinstrument that allows for in situ surface analysis. The evolution in contact resistance, morphology, and chemistry is probed as a function of contact cycle. Initially, the contact resistance is found to decrease and then increase with impact cycle. Upon prolonged cycling, the fracture of Si grains is observed which grow to form a wear crater. The electrical, morphological, and chemical analyses suggest that the wear of rough polysilicon surfaces due to impact proceeds through three distinct phases, namely plastic deformation of asperities, adhesive wear, and grain fracture.

Liu, Fang; Laboriante, Ian; Bush, Brian; Roper, Christopher S.; Carraro, Carlo; Maboudian, Roya

2009-09-01

423

Effects of Contact Time and Polarity Level on Adhesion  

NASA Astrophysics Data System (ADS)

We have measured the rate at which adhesion develops between two surfaces that interact by hydrogen bonding. A polydimethylsiloxane elastomer lens with a slightly oxidized surface was pushed against a polystyrene based copolymer substrate that contained acid groups. The interaction was measured on both forming and breaking the contact using the JKR technique. The toughness of the joint, G_c, increased considerably with increasing acid content in the substrate whilst the apparent work of adhesion, W, measured whilst making the contact, decreased with increasing acid content. This decrease in W implies that the acid groups caused repulsion between the surfaces when they were not in contact, but the increase in Gc shows that they formed bonds after contact was made. The rate of increase of Gc with time was found to depend on the acid content in the substrate but, for moderate acid levels, Gc was found to saturate at values that varied approximately linearly with acid content. For 8%acid and 47%acid substrates the rate of adhesion development over a period of 24 hours could be fitted by a model assuming (i) the toughness increased linearly with areal density of bonds between the substrate and the elastomer and (ii) the rate of reaction between the substrate and the elastomer varied as the cube of the density of unreacted acid groups. This cube law may possibly be explained by the kinetics of motion of the elastomer chains on the substrate.

Brown, Hugh; Girard-Reydet, Emmanuel

2004-03-01

424

Interdigitated back contact solar cells  

NASA Astrophysics Data System (ADS)

The interdigitated back contact solar cell (IBC cell) was shown to possess a number of advantages for silicon solar cells, which operate at high concentration. A detailed discussion of the factors which need to be considered in the analysis of semiconducting devices which utilize heavily doped regions such as those which are found in solar cells in both the emitter and in the back surface field regions is given. This discussion covers the questions of: how to handle degeneracy, how to compute carrier concentrations in the absence of knowledge of the details of the band structure under heavily doped conditions, and how to reconcile the usual interpretation of heavy doping as a rigid shift of the bands with the band tailing and impurity level conduction models. It also discusses the reasons for the observed discrepancies between various experimental measurements of bandgap narrowing.

Lundstrom, M. S.; Schwartz, R. J.

1980-08-01

425

Moulding process for contact lens  

NASA Astrophysics Data System (ADS)

Cast molding of contact lenses from a polymerizable monomer composition, encapsulated between two molds, offers a route to a highly reproducible product. Unfortunately, some of the reproducible characteristics are not desirable. In particular, the edge profile is often uneven and causes patient discomfort, or worse. To ensure a good quality edge with current molding processes, it is necessary to polish it. In the polishing steps the final edge profile can vary, but in addition other faults such as scratches and tears, not to mention general handling faults, depress yields and reduce the quality of a perfectly molded lens. This paper describes a process which not only produces a uniform, safe, and comfortable edge but which, by SPC methods, reduces all handling to a minimum and ensures the patient receives a healthy lens of consistently high quality.

Skipper, Richard S.; Shepherd, David W.

1991-12-01

426

Contact dermatitis in Israeli soldiers.  

PubMed

This report consists of an evaluation of 41 soldiers from the infantry, armored, and artillery division, who developed hand dermatitis from their contact with oils and fuel. A special "tailored" supplementary tray with five reagents relevant to their field of work and environment was performed. The reagents that were used were gun oil, hydraulic oil, automotive lubricant (oil) 20/50, white spirit, and car petrol (gasoline). Seven of the 41 patients (17%) showed one or more positive tests to the supplementary tray. The fact that none of the control group of 64 patients not exposed to these substances showed a positive result to the supplementary tray indicates that false positive results are, at least, not probable. It is suggested that soldiers with occupational hand dermatitis should be tested with supplemental aimed trays that are relevant to their work and environment, in addition to the standard trays. PMID:8078094

Wolf, R; Movshowitz, M; Brenner, S

1994-09-01

427

Contact hole imaging characteristics from projection lithography.  

PubMed

Image intensity profiles (IIPs) are calculated for selected cross sections of contact hole arrays for a circular source and objective in the presence of the defocus aberration. The IIPs for selected cross sections of contact holes are compared with IlPs from correspondingly dimensioned gratings. At resolution levels equal to or greater than 0.9 lambda/N.A., the predicted contact hole image quality should be similar to that attainable from correspondingly dimensioned line-space gratings. Although the shapes of the contact holes appear to be predicted well, in some cases the experimental contact hole to grating dimensional comparison indicates significantly less than perfect imaging characteristics. Advanced lens systems with similar resolution ratios but different depth of focus characteristics are also compared for contact hole imaging. Contact hole imaging characteristics are much more sensitive to residual aberrations in the optical lens system and can provide a convenient measure of the relative magnitude of these aberrations. PMID:20489872

White, L K

1987-06-15

428

Dynamic contact stiffness of vibrating rigid sphere contacting semi-infinite transversely isotropic viscoelastic solid  

Microsoft Academic Search

Dynamic contact stiffness at the interface between a vibrating rigid sphere and a semi-infinite transversely isotropic viscoelastic solid is investigated. An oscillating force superimposed onto a static compressive force in the vertical direction excites the vibration of a rigid sphere, which causes variable contact radius and contact pressure distribution in the contact region. The assumption of a sufficiently small oscillating

Jiayong Tian; Zhoumin Xie

2008-01-01

429

Exploration of Tactile Contact in a Haptic Display: Effects of Contact Velocity and Transient Vibrations  

Microsoft Academic Search

Experiments were conducted using a novel tactile contact rendering device to explore important factors of the tactile contact event. The effects of contact velocity and event-based transient vibrations were explored. Our research was motivated by a need to better understand the perception of the tactile contact event and to develop a means of rendering stiff surfaces with a nonspecialized haptic

Brian T. Gleeson; William R. Provancher

2011-01-01

430

The effect of contact capacitance on current-voltage characteristics of stationary metal contacts  

Microsoft Academic Search

This paper investigates experimentally the significance of the effective contact capacitance, i.e., the interfacial capacitance during the current flow, for a wide range of stationary metal contacts operating under high charge injection rates. The effective capacitance of metallic interfaces depends on the ratio between the apparent contact area (which is optically determined) and the effective contact area (which injects the

Constantine T. Dervos; Joseph M. Michaelides

1998-01-01

431

Wheel–rail contact models for vehicle system dynamics including multi-point contact  

Microsoft Academic Search

Advanced modelling of rail vehicle dynamics requires realistic solutions of contact problems for wheels and rails that are able to describe contact singularities, encountered for wheels and rails. The basic singularities demonstrate themselves as double and multiple contact patches. The solutions of the contact problems have to be known practically in each step of the numerical integration of the differential

J. Piotrowski; H. Chollet

2005-01-01

432

Analysis of indeterminate contact forces in robotic grasping and contact tasks  

Microsoft Academic Search

In this paper, we analyze indeterminate contact forces in robotic grasping and contact tasks. Previous studies by Omata and Nagata showed that there is a constraint on static friction forces, which is derived from contact kinematics, in rigid-body power grasps. The set of possible contact forces can be calculated using the constraint. This approach can be applied to not only

Yusuke Maeda; Koutarou Oda; Satoshi Makita

2007-01-01

433

Unsaturated water flow across soil aggregate contacts  

NASA Astrophysics Data System (ADS)

Unsaturated water flow through soil aggregates is controlled by the contacts between aggregates. The contacts are highly conductive when wet and become bottle-necks for flow when drained. We postulate that the hydraulic conductivity of the contacts is in first place determined by the water-filled contact area. The objective of this study was to measure and model the water-filled contact area and to relate it to the conductivity of a series of aggregates. We performed microscopic tomography of an aggregate pair equilibrated at different water potentials. By means of image analysis and a morphological pore network model, the water-filled contact area was calculated. We found that the aggregate surface is rough and the contact region contains macropores which are rapidly drained. As a consequence the water-filled contact area dramatically decreases as the water potential is diminished. We modeled this process by describing the aggregates as spheres covered by much smaller spheres representing the roughness. The water-filled contact was analytically calculated from this model. Knowing the water-filled contact area we up-scale the hydraulic conductivity of a series of aggregates. This is calculated as the harmonic mean of the contact and aggregate conductivities. The contact conductivity is calculated from the water-filled contact area. Near saturation the conductivity of a series of aggregates is close to the conductivity of a single aggregate, and, when further drained, it rapidly decreases as the water-filled contact area. The model matches the experimental data well.

Carminati, A.; Kaestner, A.; Lehmann, P.; Flühler, H.

2008-09-01

434

Investigation on plated Ni/Cu contact for mono-crystalline silicon solar cells  

NASA Astrophysics Data System (ADS)

Silicon solar cells are required to be processed with low cost and high efficiency. Ag paste, which is frequently used for the front contact of commercial screen-printed solar cells, has high contact resistance and high cost. Therefore, it is necessary to develop an inexpensive metallization technique with improved cell performance. As an alternative, plated Ni/Cu contact was used to fabricate low cost and high efficiency solar cells in this paper. Ni/Cu metals have low cost, low contact resistance and high conductivity. Ni was formed for low contact resistance and barrier to plated Cu, which was the main contact for low cost and high conductivity. In particular, a plated Ni layer is a very crucial factor that determines performance of the contact for plated Ni/Cu solar cells. A plated Ni layer has a decisive effect on contact resistance, series resistance and fill factor. In this paper, Ni electroless plating conditions (deposition time and pH) were varied to form a well plated Ni layer. For an optimized Ni electroless plating condition (5 min of deposition time and 8.5 of pH), the efficiency of plated Ni/Cu contact solar cells recorded 18.68%.

Kim, Dong Ho; Lee, Soo Hong

2013-09-01

435

Rational Design of Potent, Small, Synthetic Allosteric Inhibitors of Thrombin  

PubMed Central

Thrombin is a key enzyme targeted by the majority of current anticoagulants that are direct inhibitors. Allosteric inhibition of thrombin may offer a major advantage of finely tuned regulation. We present here sulfated benzofurans as the first examples of potent, small allosteric inhibitors of thrombin. A sulfated benzofuran library of 15 sulfated monomers and 13 sulfated dimers with different charged, polar and hydrophobic substituents was studied in this work. Synthesis of the sulfated benzofurans was achieved through a multiple step, highly branched strategy, which culminated with microwave-assisted chemical sulfation. Of the 28 potential inhibitors, eleven exhibited reasonable inhibition of human ?-thrombin at pH 7.4. Structure activity relationship analysis indicated that sulfation at the 5-position of the benzofuran scaffold was essential for targeting thrombin. A t-butyl 5-sulfated benzofuran derivative was found to be the most potent thrombin inhibitor with an IC50 of 7.3 ?M under physiologically relevant conditions. Michaelis-Menten studies showed an allosteric inhibition phenomenon. Plasma clotting assays indicate that the sulfated benzofurans prolong both the activated partial thromboplastin time and prothrombin time. Overall, this work puts forward sulfated benzofurans as the first small, synthetic molecules as powerful lead compounds for the design of a new class of allosteric inhibitors of thrombin.

Sidhu, Preetpal Singh; Liang, Aiye; Mehta, Akul Y.; Abdel Aziz, May H.; Zhou, Qibing; Desai, Umesh R.

2011-01-01

436

Synthesis of uronic-noeurostegine--a potent bacterial ?-glucuronidase inhibitor.  

PubMed

Inhibition of ?-glucuronidases has recently been shown to be useful in alleviating drug toxicity for common colon cancer chemotherapeutic CPT-11 (also called Irinotecan). We have prepared a new compound of the nortropane-type, uronic-Noeurostegine, and demonstrated that this is a competitive and potent E. coli ?-glucuronidase inhibitor, while inhibition of the mammalian ?-glucuronidase from bovine liver was found to be less significant. Although not intended, two other compounds having N-ethyl and N-(4-hydroxybutyl) substituents were also prepared in this study due to the sluggish debenzylation in the final step. The N-substituents are believed to come from reaction with the solvents used being ethanol and THF, respectively. These compounds also inhibited the two ?-glucuronidases albeit to a lesser extent compared to the parent compound. Noeurostegine and the three uronic-noeurostegines were additionally evaluated as inhibitors against a wide panel of glycosidases with the former showing potent inhibition of rat intestinal lactase and trehalase, whereas the latter was found to be inactive. PMID:21952673

Rasmussen, Tina S; Koldsø, Heidi; Nakagawa, Shinpei; Kato, Atsushi; Schiøtt, Birgit; Jensen, Henrik H

2011-09-27

437

Potent hypoglycemic effect of Nigerian anti-diabetic medicinal plants.  

PubMed

The objective of this paper was to investigate the phytochemistry and hypoglycemic activities of aqueous extracts of Anisopus mannii, Daniella olivieri, Detarium macrocarpum, Leptedenia hastate and Mimosa invisa, traditionally prescribed for diabetes mellitus. The aqueous extracts were tested for phytochemicals and free radical scavenging activity by the DPPH assay. The antidiabetic tests were performed in normoglycemic and alloxan induced diabetic mice. High intensity of saponins, xanthones, tannins and glycosides were detected in A. mannii, D. macrocarpum and M. invisa, respectively. For the free radical scavenging activity, D. macrocarpum showed the highest activity with an IC50 of 0.027 mg/ml which was 2.1 folds of ascorbic acid. All extracts showed potent hypoglycemic effects in alloxan induced diabetic mice with the highest fasting blood glucose reduction of 70.39 percent in A. mannii which was 1.54 and 0.98 fold of glibenclamide and human insulin, respectively. A. mannii showed the potent hypoglycemic activity which was 1.54 and 0.98 fold of glibenclamide and insulin, respectively. This study confirmed the traditional use of these Nigerian medicinal plants in diabetes treatment. These plants showed high potential for further investigation to novel anti-diabetic drugs. PMID:22754948

Manosroi, Jiradej; Zaruwa, Moses Z; Manosroi, Aranya

2011-01-01

438

Potent Inhibition of HIV-1 Replication by a Tat Mutant  

PubMed Central

Herein we describe a mutant of the two-exon HIV-1 Tat protein, termed Nullbasic, that potently inhibits multiple steps of the HIV-1 replication cycle. Nullbasic was created by replacing the entire arginine-rich basic domain of wild type Tat with glycine/alanine residues. Like similarly mutated one-exon Tat mutants, Nullbasic exhibited transdominant negative effects on Tat-dependent transactivation. However, unlike previously reported mutants, we discovered that Nullbasic also strongly suppressed the expression of unspliced and singly-spliced viral mRNA, an activity likely caused by redistribution and thus functional inhibition of HIV-1 Rev. Furthermore, HIV-1 virion particles produced by cells expressing Nullbasic had severely reduced infectivity, a defect attributable to a reduced ability of the virions to undergo reverse transcription. Combination of these inhibitory effects on transactivation, Rev-dependent mRNA transport and reverse transcription meant that permissive cells constitutively expressing Nullbasic were highly resistant to a spreading infection by HIV-1. Nullbasic and its activities thus provide potential insights into the development of potent antiviral therapeutics that target multiple stages of HIV-1 infection.

Major, Lee; Suhrbier, Andreas; Harrich, David

2009-01-01

439

Molecular dynamics characterization of the contact between clean metallic surfaces with nanoscale asperities  

NASA Astrophysics Data System (ADS)

We use molecular dynamics (MD) simulations to characterize the tensile strength of contacts formed between various clean platinum surfaces with nanoscale asperities. Both commensurate contacts between (001) and (111) surfaces and incommensurate (001) ones are considered over a wide range of asperity sizes. In cyclic closing and opening, fresh asperities that form contacts for the first time show significant plastic deformation; this leads to a reduction in the effective contact area during the first few cycles, after which steady state is achieved both in terms of contact size and the pull-out force necessary to open the contacts. As is the case for commensurate surfaces [H. Kim and A. Strachan, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.104.215504 104, 215504 (2010)], the strength of the metallic bridges that form in incommensurate contacts exhibit strong size effects; their strength increases with decreasing size until a length of ˜5 nm, below which weakening is observed. Commensurate contacts lead to stronger bridges than incommensurate ones but only during the initial closing events; after steady state is achieved, commensurate and incommensurate (001) surfaces lead to bridges of similar strengths.

Kim, Hojin; Strachan, Alejandro

2011-01-01

440

Numerical Study of Asperity Distribution in an Electrical Contact  

Microsoft Academic Search

Electrical contacts consists of parts where the surfaces are in contact and where the actual physical contact occur just in a few contact asperity points scattered over the whole apparent contact area. Through these contact spots between the mating bodies the mechanical load and the electric current is transmitted. Often a soft coating is used to enlarge the real contact

Per Lindholm

2011-01-01

441

Ohmic contact to n-type Ge with compositional Ti nitride  

NASA Astrophysics Data System (ADS)

Fermi-Level pinning at Ge surface results in high Schottky barrier height (SBH) for nearly all metal/n-Ge contacts. By varying composition of the TiNx, modulation of the SBH was demonstrated for TiNx/n-Ge contact. The effective SBH of the TiN0.1/n-Ge Schottky contact was found decreased to 0.45 eV, as compared to the Ti/n-Ge contact SBH which was originally pinned at 0.56 eV. Ohmic contact to n-type Ge was realized by increasing the nitrogen composition to x = 0.8 in TiNx. Dipoles formed by the difference of the Pauling electronegativities for Ge and N at the contact interface is proposed to alleviate the Fermi-Level pinning effect.

Wu, H. D.; Huang, W.; Lu, W. F.; Tang, R. F.; Li, C.; Lai, H. K.; Chen, S. Y.; Xue, C. L.

2013-11-01

442

Completely Integrable Contact Hamiltonian Systems and Toric Contact Structures on S^2×S^3  

NASA Astrophysics Data System (ADS)

I begin by giving a general discussion of completely integrable Hamiltonian systems in the setting of contact geometry. We then pass to the particular case of toric contact structures on the manifold S2×S3. In particular we give a complete solution to the contact equivalence problem for a class of toric contact structures, Yp,q, discovered by physicists by showing that Yp,q and Yp',q' are inequivalent as contact structures if and only if p?p'.

Boyer, Charles P.

2011-06-01

443

Reliability of Semiautomated Computational Methods for Estimating Tibiofemoral Contact Stress in the Multicenter Osteoarthritis Study  

PubMed Central

Recent findings suggest that contact stress is a potent predictor of subsequent symptomatic osteoarthritis development in the knee. However, much larger numbers of knees (likely on the order of hundreds, if not thousands) need to be reliably analyzed to achieve the statistical power necessary to clarify this relationship. This study assessed the reliability of new semiautomated computational methods for estimating contact stress in knees from large population-based cohorts. Ten knees of subjects from the Multicenter Osteoarthritis Study were included. Bone surfaces were manually segmented from sequential 1.0 Tesla magnetic resonance imaging slices by three individuals on two nonconsecutive days. Four individuals then registered the resulting bone surfaces to corresponding bone edges on weight-bearing radiographs, using a semi-automated algorithm. Discrete element analysis methods were used to estimate contact stress distributions for each knee. Segmentation and registration reliabilities (day-to-day and interrater) for peak and mean medial and lateral tibiofemoral contact stress were assessed with Shrout-Fleiss intraclass correlation coefficients (ICCs). The segmentation and registration steps of the modeling approach were found to have excellent day-to-day (ICC 0.93–0.99) and good inter-rater reliability (0.84–0.97). This approach for estimating compartment-specific tibiofemoral contact stress appears to be sufficiently reliable for use in large population-based cohorts.

Anderson, Donald D.; Segal, Neil A.; Kern, Andrew M.; Nevitt, Michael C.; Torner, James C.; Lynch, John A.

2012-01-01

444

Cell-Cell Transmission Enables HIV-1 to Evade Inhibition by Potent CD4bs Directed Antibodies  

PubMed Central

HIV is known to spread efficiently both in a cell-free state and from cell to cell, however the relative importance of the cell-cell transmission mode in natural infection has not yet been resolved. Likewise to what extent cell-cell transmission is vulnerable to inhibition by neutralizing antibodies and entry inhibitors remains to be determined. Here we report on neutralizing antibody activity during cell-cell transmission using specifically tailored experimental strategies which enable unambiguous discrimination between the two transmission routes. We demonstrate that the activity of neutralizing monoclonal antibodies (mAbs) and entry inhibitors during cell-cell transmission varies depending on their mode of action. While gp41 directed agents remain active, CD4 binding site (CD4bs) directed inhibitors, including the potent neutralizing mAb VRC01, dramatically lose potency during cell-cell transmission. This implies that CD4bs mAbs act preferentially through blocking free virus transmission, while still allowing HIV to spread through cell-cell contacts. Thus providing a plausible explanation for how HIV maintains infectivity and rapidly escapes potent and broadly active CD4bs directed antibody responses in vivo.

Schanz, Merle; Reynell, Lucy; Gunthard, Huldrych F.; Rusert, Peter; Trkola, Alexandra

2012-01-01

445

Cell-cell transmission enables HIV-1 to evade inhibition by potent CD4bs directed antibodies.  

PubMed

HIV is known to spread efficiently both in a cell-free state and from cell to cell, however the relative importance of the cell-cell transmission mode in natural infection has not yet been resolved. Likewise to what extent cell-cell transmission is vulnerable to inhibition by neutralizing antibodies and entry inhibitors remains to be determined. Here we report on neutralizing antibody activity during cell-cell transmission using specifically tailored experimental strategies which enable unambiguous discrimination between the two transmission routes. We demonstrate that the activity of neutralizing monoclonal antibodies (mAbs) and entry inhibitors during cell-cell transmission varies depending on their mode of action. While gp41 directed agents remain active, CD4 binding site (CD4bs) directed inhibitors, including the potent neutralizing mAb VRC01, dramatically lose potency during cell-cell transmission. This implies that CD4bs mAbs act preferentially through blocking free virus transmission, while still allowing HIV to spread through cell-cell contacts. Thus providing a plausible explanation for how HIV maintains infectivity and rapidly escapes potent and broadly active CD4bs directed antibody responses in vivo. PMID:22496655

Abela, Irene A; Berlinger, Livia; Schanz, Merle; Reynell, Lucy; Günthard, Huldrych F; Rusert, Peter; Trkola, Alexandra

2012-04-05

446

Formulations and computational methods for contact problems in solid mechanics  

NASA Astrophysics Data System (ADS)

A study of existing formulations and computational methods for contact problems is conducted. The purpose is to gain insights into the solution procedures and pinpoint their limitations so that alternate procedures can be developed. Three such procedures based on the augmented Lagrangian method (ALM) are proposed. Small-scale benchmark problems are solved analytically as well as numerically to study the existing and proposed methods. The variational inequality formulation for frictionless contact is studied using the two bar truss-wall problem in a closed form. Sub-differential formulation is investigated using the spring-wall contact and the truss-wall friction problems. A two-phase analytical procedure is developed for solving the truss-wall frictional contact benchmark problem. The variational equality formulation for contact problems is studied using the penalty method along with the Newton-Raphson procedure. Limitations of such procedures, mainly due to their dependence on the user defined parameters (i.e., the penalty values and the number of time steps), are identified. Based on the study it is concluded that alternate formulations need to be developed. Frictionless contact formulation is developed using the basic concepts of ALM from optimization theory. A new frictional contact formulation (ALM1) is then developed employing ALM. Automatic penalty update procedure is used to eliminate dependence of the solution on the penalty values. Dependence of the solution on the number of time steps in the existing as well as ALM1 formulations is attributed to a flaw in the return mapping procedure for friction. Another new frictional contact formulation (ALM2) is developed to eliminate the dependence of solution on the number of time steps along with the penalty values. Effectiveness of ALM2 is demonstrated by solving the two bar and five bar truss-wall problems. The solutions are compared with the analytical and existing formulations. Design sensitivity analysis of frictional contact problems is also studied and potential advantages of ALM2 over the existing formulations to obtain the sensitivity coefficients are identified. Finally, future directions of the research and conclusions are given.

Mirar, Anand Ramchandra

447

Mechanical Response of Living Cells to Contacting Shear Forces  

Microsoft Academic Search

\\u000a Cells adjacent to implanted devices often experience stress in the form of shearing forces from relative motion with those\\u000a devices. Cell response to contacting shear, specifically in the reorganization of the cytoskeletal actin fibrils, is not yet\\u000a fully understood. Many techniques such as atomic force microscopy and micro-pipette aspiration are currently used to deform\\u000a or stress cells in a controlled

Alison C. Dunn; W. Gregory Sawyer; Malisa Sarntinoranont; Roger Tran-Son-Tay

448

Coffee Drops and Coffee Rings: Contact Line Deposits from Evaporation  

NASA Astrophysics Data System (ADS)

When a small drop of coffee placed on a counter top dries, it deposits a thin ring of concentrated solute at the perimeter of the drop. Similar rings form for a wide range of surfaces, solutes, and solvents, provided the contact line is pinned to the surface. An old result of Maxwell can be used to partially explain these dense rings. The predicted rate of ring deposition is shown to agree quantitatively with experimental measurements.

Huber, Greg

1997-03-01

449

Deagglomeration of Transfer Film in Metal Contacts Using Nanolubricants  

Microsoft Academic Search

Experimental results presented in this paper reveal the ability of nanoparticle-dispersed engine oil (nanolubricant) to deagglomerate the metallic transfer films under extreme pressures. Specifically, metallic transfer films were formed and accumulated on the upper AISI 52100 ball in a four-ball tester which resulted in negative wear, i.e. weight gain, under Hertzian contact pressures ranging from 3.4 to 5.5 GPa. When

M. Mosleh; M. Ghaderi

2011-01-01

450

Deagglomeration of Transfer Film in Metal Contacts Using Nanolubricants  

Microsoft Academic Search

Experimental results presented in this article reveal the ability of nanoparticle-dispersed engine oil (nanolubricant) to deagglomerate metallic transfer films under extreme pressures. Specifically, metallic transfer films were formed and accumulated on the upper AISI 52100 ball in a four-ball tester, which resulted in negative wear—that is, weight gain—under Hertzian contact pressures ranging from 3.4 to 5.5 GPa. When molybdenum disulfide

M. Mosleh; M. Ghaderi

2012-01-01

451

Ionic conductivity in hydrogels for contact lens applications  

Microsoft Academic Search

Biphasic hydrogel polymers are in the forefront of new extended wear contact lens development. In the biphasic hydrogel the\\u000a objective is to produce co-continuous domains of siloxane units for high oxygen permeability, coupled with hydrophilic units\\u000a forming aqueous channels for hydraulic and ion mobility. These are distributed in phase separated nano-scale regions such\\u000a that the material is optically clear while

David Austin; R. V. Kumar

2005-01-01

452

Application of Infrared Thermography for Contact Problems  

NASA Astrophysics Data System (ADS)

Several experimental investigations of contact problems were made by the use of infrared thermography. A new experimental technique using infrared thermography combined with infrared transmitting materials was applied for continuous monitoring of the temperature distribution on the contact surface. Contact temperature measurement was examined for dry sliding contact of a plastic pin with an infrared transmitting disk. It was found that steady state contact surface temperature distribution was accurately monitored by thermography. Contact stress field was measured by an infrared stress measurement system based on the thermoelasticity through an infrared transmitting solid. It was found that the contact stress field was successfully visualized by the proposed method. Finally, a newly available infrared thermography system was used to characterize the near-surface conditions associated with fretting contact. It was found that both frictional temperature rise due to the interfacial global slip and the temperature fluctuation due to thermoelasticity can be measured to evaluate the nature of the contact stress field and the mechanics of partial slip fretting contacts.

Sakagami, T.; Ogura, K.; Kubo, S.; Farris, T. N.

453

Electrical contact at the interface between silicon and transfer-printed gold films by eutectic joining.  

PubMed

This paper presents the electrical and morphological properties at the interface between a metal (Au) and a semiconductor (Si) formed by a novel transfer-printing technology. This work shows that a transfer-printed thin (hundreds of nanometers) Au film forms excellent electrical contact on a Si substrate when appropriate thermal treatment is applied. The successful electrical contact is attributed to eutectic joining, which allows for the right amount of atomic level mass transport between Au and Si. The outcomes suggest that transfer-printing-based micromanufacturing can realize not only strong mechanical bonding but also high-quality electrical contact via eutectic joining. PMID:23751269

Keum, Hohyun; Chung, Hyun-Joong; Kim, Seok

2013-06-20

454

Amphibian glucagon family peptides: potent metabolic regulators in fish hepatocytes.  

PubMed

Peptides analogous to glucagon-like peptide-1 (GLP-1) have been isolated from amphibian pancreas and intestine, and their amino acid sequences and cDNA structures elucidated. Just like their mammalian counterpart, these peptides are potent insulinotropins in mammalian pancreatic cells. We show here that these peptides also exert strong glycogenolytic actions when applied to dispersed fish hepatocytes. We compared the potencies of three synthetic GLP-1s from Xenopus laevis and two native GLP-1s from Bufo marinus in the activation of glycogenolysis in the hepatocytes of a marine rockfish (Sebastes caurinus) and two freshwater catfish (Ameiurus nebulosus and A. melas), and demonstrated their effectiveness in increasing the degree of phosphorylation of glycogen phosphorylase. We also compared the glycogenolytic potency of the peptides with those of human GLP-1 and glucagons from human and B. marinus. Sensitivity to these peptides is species-specific, with the rockfish responding at lower concentrations to GLP-1s and the two catfish reacting better to glucagons. However, the relative potency of the amphibian GLP-1s and glucagons is similar in the three species. Xenopus GLP-1C (xGLP-1C) is consistently more potent than xGLP-1B, while xGLP-1A displays the smallest activation of glycogenolysis. Similarly, Bufo GLP-1(32)-the peptide with the highest amino acid sequence identity to xGLP-1C-always shows a higher potency than Bufo GLP-1(37), which is closely related to xGLP-1B. The relative hierarchy of these glycogenolytic GLP-1s differs from their ranking as insulinotropins in mammalian beta-cells. In the rockfish system, Bufo glucagon-36, a C-terminally extended glucagon, is more potent than the shorter bovine glucagon and Bufo glucagon-29 in the activation of glycogenolysis; when tested in A. nebulosus hepatocytes, bovine and amphibian glucagons are equipotent. Amphibian GLP-1s and glucagons activate glycogenolysis in fish hepatocytes through increased phosphorylation of glycogen phosphorylase, implying involvement of the adenylyl cyclase/protein kinase A system in signal transduction. We conclude that the broad physiological effectiveness of GLP-1 has been retained throughout vertebrate evolution, and that both insulinotropic activity and glycogenolytic actions belong to the repertoire of GLP-1. PMID:11384772

Mommsen, T P; Conlon, J M; Irwin, D M

2001-06-15

455

Allergic contact dermatitis to chlorhexidine.  

PubMed

Chlorhexidine is a commonly used antiseptic agent in the health-care setting. Although exposure to chlorhexidine is very common, allergic contact dermatitis (ACD) is rarely reported. We report a case series of ACD to chlorhexidine in health-care workers and discuss our rates of allergy to chlorhexidine, from patch-testing performed at the Skin and Cancer Foundation, Melbourne, Australia. Of 7890 patients patch-tested, 840 patients were tested to 0.5% chlorhexidine diacetate with 28 (3%) positive reactions, 13 (2%) of which relevant to their presenting dermatitis. Altogether 1565 patients were tested to 0.5% chlorhexidine digluconate, with 47 (3%) positive reactions, 16 (1%) of which were relevant. We estimate our rate of relevant chlorhexidine ACD from our total clinic patients, non-occupational and occupational, to be at least 19/7890 (0.24%). Our rate of relevant chlorhexidine ACD in health-care workers is 10/541 (2%). Interestingly, our rates of chlorhexidine allergy are slightly higher than documented elsewhere. This raises the possibility that chlorhexidine is underestimated as an allergen worldwide, and should be tested for in health-care workers where there is a history of exposure. PMID:23789882

Toholka, Ryan; Nixon, Rosemary

2013-06-23

456

Microelectromechanical systems contact stress sensor  

DOEpatents

A microelectromechanical systems stress sensor comprising a microelectromechanical systems silicon body. A recess is formed in the silicon body. A silicon element extends into the recess. The silicon element has limited freedom of movement within the recess. An electrical circuit in the silicon element includes a piezoresistor material that allows for sensing changes in resistance that is proportional to bending of the silicon element.

Kotovsky, Jack (Oakland, CA)

2007-12-25

457

Low k1 Contact Hole Formation by Double Line and Space Formation Method with Contact Hole Mask and Dipole Illumination  

Microsoft Academic Search

The double line and space (L&S) formation method was proved to have the capability to form contact hole (C\\/H) patterns with high resolution and wide process windows. The drawback of the method is its high cost. By replacing two L&S masks by one C\\/H mask with dipole illumination, high performance and mask cost reduction were targeted. The 75 nm (0.33-k1)

Hiroko Nakamura; Kazuya Sato; Satoshi Tanaka; Yasuyuki Taniguchi; Junko Abe; Shoji Mimotogi; Soichi Inoue

2006-01-01

458

Focal Contacts as Mechanosensors: Externally Applied Local Mechanical Force Induces Growth of Focal Contacts by an Mdia1Dependent and Rock-Independent Mechanism  

Microsoft Academic Search

The transition of cell-matrix adhesions from the initial punctate focal complexes into the mature elon- gated form, known as focal contacts, requires GTPase Rho activity. In particular, activation of myosin II-driven contractility by a Rho target known as Rho-associated ki- nase (ROCK) was shown to be essential for focal contact formation. To dissect the mechanism of Rho-dependent induction of focal

Daniel Riveline; Eli Zamir; Nathalie Q. Balaban; Ulrich S. Schwarz; Toshimasa Ishizaki; Shuh Narumiya; Zvi Kam; Benjamin Geiger; Alexander D. Bershadsky

2001-01-01

459

Industrial airborne irritant or allergic contact dermatitis.  

PubMed

Industrial airborne irritant or allergic contact dermatitis is commonly observed in many factories. Examples of airborne irritants include fibres (such as fibreglass or rockwool), various kinds of dust particles (such as cement, slag, sludge, insulating foam, wood chips), acids and alkalis, gasses and vapours. Airborne contact allergens are unequivocally numerous. The clinical symptoms of both irritant and allergic airborne contact dermatitis are reviewed. PMID:2940059

Lachapelle, J M

1986-03-01

460

High Current AC Break Arc Contact Erosion  

Microsoft Academic Search

Contact break arc erosion fundamentals applicable to high power switching devices in air (e.g. air- magnetic circuit breakers and contactors) are reviewed along with recent results showing dominant factors that affect contact erosion in the range of 3 kAp to 22 kAp. Background covers a review of arc plasma theory pertaining to contact erosion in air at atmospheric pressure including

John J. Shea

2008-01-01

461

Occupational allergic contact dermatitis due to thioureas.  

PubMed

Thioureas are used as additives in rubber products and as antidegradants for natural rubber latex. They are an uncommon cause of allergic contact dermatitis. This case represents an example of occupational allergic contact dermatitis solely from thioureas in rubber products and no cross-reactivity with other rubber allergens. Standard patch tests may fail to detect thiourea-induced allergic contact dermatitis, so clinicians should consider thiourea sensitization in rubber allergy. PMID:20137733

Kohli, Nita; Habbal, Souheil

462