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1

Indirect inhibition of polymerization of a polyvinyl siloxane impression material: a case report.  

PubMed

The inhibition of polymerization of polyvinyl siloxane impression materials by direct contact with latex gloves has been well documented. Indirect intraoral inhibition of polymerization that results from contact of oral tissues with latex gloves during tooth preparation and gingival retraction procedures has been reported. This case report illustrates the problems that can occur when the dentist used polyvinyl siloxane impression materials while wearing latex gloves. In the reported case, the inhibition is severe and obvious; in most situations the inhibition of polymerization is more subtle and is frequently undetected. Clinicians must be aware of this potential problem and the solution to it. PMID:2068247

Chee, W W; Donovan, T E; Kahn, R L

1991-02-01

2

Interaction of gloves and rubber dam with a poly(vinyl siloxane) impression material: a screening test.  

PubMed

Polymerization inhibition of poly(vinyl siloxane) impression materials has been reported with the use of latex gloves. This study evaluated the effect on polymerization of a poly(vinyl siloxane) impression material in both direct and indirect contact with 25 brands of latex gloves, two brands of vinyl gloves, and two weights of rubber dam. Use of all but one of the latex products (96%) resulted in inhibition of polymerization with direct contact. Forty percent of the latex gloves tested inhibited polymerization with indirect contact. The vinyl gloves tested had no effect on polymerization. The implications of inhibited polymerization were discussed. PMID:2638846

Kahn, R L; Donovan, T E; Chee, W W

3

Effect of frequency and amplitude of vibration and role of a surfactant on void formation in models poured from polyvinyl siloxane impressions  

PubMed Central

Aims: To determine whether the frequency and amplitude of vibration and the use of surfactant has any effect on the formation of voids on the cast surface, poured from a polyvinyl siloxane impression material, using a mechanical model vibrator. Materials and Methods: A total of 100 impressions of a master die were made using Reprosil, Type 1, Medium Viscosity, Regular body, and Dentsply Caulk. The test group was subdivided into a surfactant and non-surfactant group, 50 impressions each. The impressions were poured in a dental stone with a mechanical model vibrator that was set at a vibration frequency of 3000 cycles / minute (low) and 6000 cycles / minute (high) with the help of a knob. The resultant casts were examined with a Stereomicroscope (LABOMED CZM4) under ×10 magnifications. Results: For the low and high frequencies, when surfactant and non-surfactant groups were compared, for all the amplitudes and for both the material groups, the surfactant groups resulted in fewer void formations and showed very high statistical significance (P-value = 0.001). Conclusions: The lowest mean voids were obtained for high frequency surfactant groups. Reprosil: High frequency amplitude 2 being the most prominent, produced the least mean voids (mean = 23.2000, P = 0.001, very highly significant). In comparison, the surfactant groups produced the least voids for both frequencies.

Reddy, N Kulashekar; Aparna, IN

2011-01-01

4

Effect of five brands of latex gloves on the setting time of polyvinyl siloxane putty impression materials.  

PubMed

Addition silicone impression materials have been used as impression material for more than 20 years. Although they are among the most expensive impression materials, they became popular during the past decade as they have excellent physical properties. Prevention of infection is an important aspect in dental treatment since dental professionals are routinely exposed to the wide variety of microorganisms present in saliva. Gloves are the most common protective measure used during dental treatment. The gloves are mostly made of latex. In this study, we examine how the setting time of three types polyvinyl putty materials were affected by the use of five different brands of latex gloves and one brand of vinyl gloves. Each material was first mixed without wearing gloves according to the manufacturer's instructions. After the stipulated mixing time, the setting time was measured using the Vicat needle. The setting time is measured from the time of mixing till the time that the needle does not produce any indentation on the surface of the material. The putty material was then mixed with gloved hands (using the five different brands of latex gloves in turn) and the setting time was measured. Then the material was mixed with washed gloved hands, and the setting time was measured again. Finally, the material was mixed with vinyl gloved hands and the setting time was measured. The following conclusions were drawn from the study: Reprosil and Express showed significant variation in the setting time with the latex gloved hands.There was no significant variation in the setting time when material was mixed with unwashed vs washed gloved hands.Vinyl gloves did not significantly affect the setting time of any of the putty impression materials. PMID:22945711

Ravikumar, C M; Sangur, Rajashekar

5

Silicone impression materials and latex gloves. Is interaction fact or fallacy?  

PubMed

This review will explore the mechanism of delayed setting and inhibition of polyvinyl siloxane impression material by latex and examine the evidence for and against this phenomenon. Clinical implications are discussed and recommendations for clinical practice made. Clinical Relevance: The production of accurate polyvinyl siloxane impressions in the fabrication of indirect restorations/prostheses is vital for a good clinical outcome. PMID:22720379

Walid, Yaman; Al-Ani, Ziad; Gray, Robin

6

Effects of chemical disinfectant solutions on the stability and accuracy of the dental impression complex  

Microsoft Academic Search

Currently available impression materials were not designed for disinfection or sterilization, and it is conceivable that disinfectants may adversely affect impressions. This study evaluated the accuracy and dimensional stability of polyether (Permadyne\\/Impregum) and polyvinyl siloxane (Express) impression materials retained by their adhesives in two different acrylic resin tray designs (perforated and nonperforated) when the materials were immersed for either 30

Maria del Pilar Rios; Steven M Morgano; R. Sheldon Stein; Lynda Rose

1996-01-01

7

Effect of surfactant on surface hardness of dental stone and investment casts produced from polyvinyl siloxane duplicating materials.  

PubMed

Polyvinylsiloxane duplicating materials are typically treated with a topical surfactant before pouring dental models, but the use of topical surfactants in the dental laboratory may affect the surface hardness of the resultant models. The effect of two different topical surfactants on surface hardness of two dental stones (FujiRock and Dentstone) and one phosphate bonded investment material (Croform WB) produced from polyvinyl siloxane (PVS) dental laboratory duplicating moulds was investigated. Topical surfactants affected the surface hardness of FujiRock, Dentstone and Croform WB investment material. Surface hardness of FujiRock increased with Wax-Mate surfactant. However, surface hardness of Croform WB investment material decreased with both topical surfactants. PMID:18637383

Al-Johani, Attalah; Clark, Robert K F; Juszczyk, Andrzej S; Radford, David R

2008-06-01

8

The effect of custom tray material type and adhesive drying time on the tensile bond strength of an impression material/adhesive system.  

PubMed

The purpose of this investigation was to compare the tensile bond strength of one poly(vinyl siloxane) impression material/adhesive system to three different custom tray materials 10 minutes, 48 hours, and 7 days after adhesive application. One autopolymerizing (Fastray) and two light-polymerizing (Triad and Extoral) custom tray resins were examined. The Triad tray resin exhibited the significantly highest mean adhesive tensile bond strengths, and the Fastray resin exhibited the lowest. It was also observed that the 48-hour adhesive drying time group exhibited the highest mean adhesive tensile bond strengths for all the materials tested, and the 10-minute group exhibited the lowest. PMID:8003192

Dixon, D L; Breeding, L C; Brown, J S

9

SILOXANE-PHOSPHONATE POLYMERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The polymerization of di- and tri-alkoxysilanes using conventional sol-gel techniques produces two and three-dimensional siloxane networks. The hydrolysis and condensation result in the formation of an alcohol under mild conditions which can be removed under reduced pressure and moderate temperature...

10

Siloxane-grafted membranes  

DOEpatents

Composite cellulosic semipermeable membranes are disclosed which are the covalently bonded reaction product of an asymmetric cellulosic semipermeable membrane and a polysiloxane containing reactive functional group. The two reactants chemically bond by ether, ester, amide or acrylate linkages to form a siloxane-grafted cellulosic membrane having superior selectivity and flux stability. Selectivity may be enhanced by wetting the surface with a swelling agent such as water.

Friesen, D.T.; Obligin, A.S.

1989-10-31

11

Assessment of Liquid Siloxanes (Silicones).  

National Technical Information Service (NTIS)

This report reviews the potential environmental hazard from the commercial use of large quantities of liquid siloxanes which are used for the most part in waxes, polishes, cosmetics, and in the foaming of polyurethane; and as lubricants, antifoaming agent...

P. H. Howard P. R. Durkin A. Hanchett

1974-01-01

12

Dinosaur Impressions  

NASA Astrophysics Data System (ADS)

Perhaps you are a paleontologist or have always wondered what it is like to be one. Or you are fascinated by fossils and like to read about the origins and natural history of dinosaurs. Or maybe you are an avid traveler and reader of travelogues. If you are any of these things, then this book is for you. Originally published in 1994 in French, Dinosaur Impressions is the engaging account of thirty years of travel and paleontological exploration by Philippe Taquet, one of the world's most noted paleontologists. Dr. Taquet takes the reader on a surprisingly far-flung tour ranging from the Provence countryside to the Niger desert, from the Brazilian bush to the Mongolian Steppes, and from the Laos jungle to the Moroccan mountains in search of dinosaur bones and what they have to tell us about a vanished world. With wry humor and lively anecdotes, Dr. Taquet retraces the history of paleontological research, along the way discussing the latest theories of dinosaur existence and extinction. Elegantly translated by Kevin Padian, Dinosaur Impressions provides a unique, thoughtful perspective not often encountered in American- and English-language works. This insightful, first-hand account of an exceptional career is also a travelogue par excellence that will enthrall enthusiasts and general readers alike. Philippe Taquet is the Director of the National Museum of Natural History in Paris and is a member of the French Academy of Sciences. Kevin Padian is a professor in the Department of Integrative Biology and Curator of the Museum of Paleontology at the University of California, Berkeley. He is also the editor of The Beginning of the Age of Dinosaurs (Cambridge, 1986) and The Encyclopedia of Dinosaurs (1997).

Taquet, Philippe

1998-09-01

13

40 CFR 721.10119 - Siloxane modified silica nanoparticles (generic).  

Code of Federal Regulations, 2013 CFR

... false Siloxane modified silica nanoparticles (generic). 721.10119 Section...10119 Siloxane modified silica nanoparticles (generic). (a) Chemical substance...generically as siloxane modified silica nanoparticles (PMN P-05-673) is subject...

2013-07-01

14

40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).  

Code of Federal Regulations, 2013 CFR

... false Siloxane modified alumina nanoparticles (generic). 721.10120 Section...10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical substance...generically as siloxane modified alumina nanoparticles (PMN P-05-687) is subject...

2013-07-01

15

40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).  

Code of Federal Regulations, 2010 CFR

... false Siloxane modified alumina nanoparticles (generic). 721.10120 Section...10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical substance...generically as siloxane modified alumina nanoparticles (PMN P-05-687) is subject...

2010-07-01

16

40 CFR 721.10119 - Siloxane modified silica nanoparticles (generic).  

Code of Federal Regulations, 2010 CFR

... false Siloxane modified silica nanoparticles (generic). 721.10119 Section...10119 Siloxane modified silica nanoparticles (generic). (a) Chemical substance...generically as siloxane modified silica nanoparticles (PMN P-05-673) is subject...

2009-07-01

17

40 CFR 721.10119 - Siloxane modified silica nanoparticles (generic).  

Code of Federal Regulations, 2010 CFR

... false Siloxane modified silica nanoparticles (generic). 721.10119 Section...10119 Siloxane modified silica nanoparticles (generic). (a) Chemical substance...generically as siloxane modified silica nanoparticles (PMN P-05-673) is subject...

2010-07-01

18

40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).  

Code of Federal Regulations, 2010 CFR

... false Siloxane modified alumina nanoparticles (generic). 721.10120 Section...10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical substance...generically as siloxane modified alumina nanoparticles (PMN P-05-687) is subject...

2009-07-01

19

Permeation of substituted silanes and siloxanes through selected gloves and protective clothing.  

PubMed

Testing of the permeation resistance of eight glove and suit barriers against commercially available substituted silanes and siloxanes was performed using the ASTM F739-96 standard test method. In addition to barrier performance to the pure organosilanes, the permeation rates of the hydrolysis product (usually ethanol or methanol) were investigated. The silanes and siloxanes used as the challenge agents were N-2-(aminoethyl)-3-aminopropyltrimethoxysilane; 3-aminopropyltriethoxysilane; 3-chloropropyltrimethoxysilane; ethyltriacetoxysilane; 3-glycidoxypropyltrimethoxysilane; 1,1,1,3,3,3-hexamethyldisilazane; hexamethyldisiloxane; 3-methacryloxypropyltrimethoxysilane; methyltriacetoxysilane (50%)/ethyltriacetoxysilane (50%); methyltrimethoxysilane; methyltris(methylethylketoxime)silane; phenyltrimethoxysilane; polydimethyl siloxanes (PS 340); octamethylcyclotetrasiloxane (D4); tetraethoxysilane; tetramethoxysilane; 1,1,3,3-tetramethyl disiloxane; triethoxysilane; trimethoxysilane; vinyltrimethoxysilane; and vinyltris(methylethylketoxime)silane. Protective gloves tested were nitrile rubber, neoprene rubber, butyl rubber, 4H laminate, and polyvinyl chloride. Garments tested included Tyvek/Saranex 23P, CPF 2, and Responder, all made by Kappler Safety Group. In all cases the protective suit materials lasted 8 hours or more. The only glove that lasted 8 hours against all chemicals was the 4H laminate. The polyvinyl chloride glove lasted 10 min to 8 hours or more depending on the chemical. The nitrile, neoprene, and butyl rubber gloves lasted from 53 min to 8 hours or more depending on the chemical. The alcohol permeation was similar to the organosilicon compounds. The suit materials and the butyl glove all lasted more than 8 hours for both methanol and ethanol. PMID:11071423

Nelson, G O; Priante, S J; Strong, M; Anderson, D; Fallon-Carine, J

20

A pilot study of polymerization inhibition of poly (vinyl siloxane) materials by latex gloves.  

PubMed

Intraoral inhibition of two poly (vinyl siloxane) low-viscosity impression materials was experienced when making an impression of prepared anterior teeth. It was hypothesized that the noted inhibition was a result of contamination with latex gloves. A screening test demonstrated inhibition of polymerization of three different materials when placed in contact with a surface that had been touched with one brand of latex gloves. This inhibition also occurred even if the gloves were washed prior to contact or if the surface was washed after contact with the gloves. Further studies are underway to determine which brands of gloves are safe to use. PMID:2597297

Kahn, R L; Donovan, T E

21

Suitability of Tedlar gas sampling bags for siloxane quantification in landfill gas.  

PubMed

Landfill or digester gas can contain man-made volatile methylsiloxanes (VMS), usually in the range of a few milligrams per normal cubic metre (Nm(3)). Until now, no standard method for siloxane quantification exists and there is controversy with respect to which sampling procedure is most suitable. This paper presents an analytical and a sampling procedure for the quantification of common VMS in biogas via GC-MS and polyvinyl fluoride (Tedlar) bags. Two commercially available Tedlar bag models are studied. One is equipped with a polypropylene valve with integrated septum, the other with a dual port fitting made from stainless steel. Siloxane recovery in landfill gas samples is investigated as a function of storage time, temperature, surface-to-volume ratio and background gas. Recovery was found to depend on the type of fitting employed. The siloxanes sampled in the bag with the polypropylene valve show high and stable recovery, even after more than 30 days. Sufficiently low detection limits below 10 microg Nm(-3) and good reproducibility can be achieved. The method is therefore well applicable to biogas, greatly facilitating sampling in comparison with other common techniques involving siloxane enrichment using sorption media. PMID:20685441

Ajhar, M; Wens, B; Stollenwerk, K H; Spalding, G; Yüce, S; Melin, T

2010-04-09

22

First Impressions Experiment  

NSDL National Science Digital Library

This is the entry page for participation in the first impressions experiment. This study allows participants to experience the formation of initial impressions and the roles minority/majority status and positive/negative attributes play in that formation process.

23

Very First Impressions  

Microsoft Academic Search

First impressions of people's personalities are often formed by using the visual appearance of their faces. Defining how quickly these impressions can be formed has critical implications for understanding social interactions and for determining the visual properties used to shape them. To study impression formation independent of emotional cues, threat judgments were made on faces with a neutral expression. Consequently,

Moshe Bar; Maital Neta; Heather Linz

2006-01-01

24

Bacteriorhodopsin oriented in polyvinyl alcohol films as an erasable optical storage medium  

Microsoft Academic Search

Films of oriented bacteriorhodopsin have been formed in polyvinyl alcohol with excellent optical quality. Images with high contrast have been impressed and erased on these films. Second-harmonic microscopy has been used to read the image on a bacteriorhodopsin-polyvinyl alcohol film without erasure. The potential of these films for molecular information storage and computation is discussed.

Zhongping Chen; Hiroyuki Takei; Aaron Lewis; Isaiah Nebenzahl

1991-01-01

25

Formulations of meta-Carborane-Siloxanes.  

National Technical Information Service (NTIS)

D2-meta-carborane-siloxane polymers have been developed for ultrahigh temperature elastomer applications. In particular, these materials have outstanding thermal stability in addition to fire and chemical resistance. Basic studies relating to resin-filler...

E. N. Peters D. D. Stewart J. J. Bohan G. T. Kwiatkowski C. D. Beard

1975-01-01

26

First impressions count.  

PubMed

The art and craft of recording intra-oral anatomy successfully with dental impressions relies on the interaction of three critical factors--the 'golden triangle of impression-taking': an appreciation of the anatomical features to be recorded, the material used to take the impression and the clinical handling/operative technique applied. This paper aims to discuss the three factors and their inter-relationships, detailing clinical tips for successful, reproducible and consistent outcomes. Clinical Relevance: Obtaining accurate dental impressions is the key to success in a wide range of clinical restorative procedures. This paper offers clinical advice to practitioners to plan and then take predictable, good quality impressions for their restorative cases. PMID:23094567

Turner, Jonathan W; Moazzez, Rebecca; Banerjee, Avijit

2012-09-01

27

Laser ablative patterning of copoly(imide siloxane)s generating superhydrophobic surfaces.  

PubMed

Low surface energy copoly(imide siloxane)s were generated via condensation polymerization reactions. The generated materials were characterized spectroscopically, thermally, mechanically, and via contact angle goniometry. The decrease in tensile modulus and opaque appearance of copoly(imide siloxane) films indicated phase segregation in the bulk. Preferential surface partitioning of the siloxane moieties was verified by X-ray photoelectron spectroscopy (XPS) and increased advancing water contact angle values (theta(A)). Pristine copoly(imide siloxane) surfaces typically exhibited theta(A) values of 111 degrees and sliding angles from 27 degrees to >60 degrees. The surface properties of these copoly(imide siloxane) films were further altered using laser ablation patterning (frequency-tripled Nd:YAG laser, 355 nm). Laser-etched square pillar arrays (25 microm pillars with 25 microm interspaces) changed theta(A) by up to 64 degrees. Theta(A) values approaching 175 degrees and sliding angles from 1 degree to 15 degrees were observed. ATR-IR spectroscopy and XPS indicated polymer chain scission reactions occurred as a result of laser ablation. Initial particle adhesion studies revealed that the copoly(imide siloxane)s outperformed the corresponding homopolyimides and that laser ablation patterning further enhanced this result. PMID:20446721

Wohl, Christopher J; Belcher, Marcus A; Chen, Lillian; Connell, John W

2010-07-01

28

Polysiloxane and Siloxane-Based Dendrimers  

NASA Astrophysics Data System (ADS)

Three different original protocols for the synthesis of siloxane dendrimers have been described. However, after appearing in the literature at much the same time they did not result in any follow-up, unlike many other strategies proposed simultaneously or even later. To appreciate the suddenness of the introduction of siloxane dendrimers and the reasons for their subsequent neglect we need to make an excursion into orga-nosiloxane chemistry. Silicones are based on a relatively small number of starting functional monomers. Moreover, their combination into new structures is restricted by the reversibility of most reactions and as a consequence by the statistical character of the main methods for the synthesis of siloxane polymers [1-3]. Although the existence of some selectivity results in the formation of useful polycyclics, the possibilities of structural control of linear and especially of branched oligomers and polymers are seriously limited. The nonequilibrium polymerization of strained cyclosiloxanes [4] is a rare exception to this rule which emphasizes the hopelessness of attempts to overcome the “statistical ill fate” that haunts the siloxane structures. All efforts to apply heterofunctional processes to achieve structural diversity are limited by this specificity of the siloxane bond and by a scanty number of appropriate reagents.

Muzafarov, Aziz; Rebrov, Evgenij

29

Siloxanes from the hydrolysis of isopropyltrimethoxysilane  

Microsoft Academic Search

The behavior of isopropyltrimethoxysilane (1 in the presence one equivalent of water and a dibutyltin dilaurate catalyst has been investigated. Under these conditions, partial hydrolysis of the methoxy groups of 1 occurred, followed by condensation reactions leading to the formation of low molecular-weight oligomers. Disiloxane 4, trisiloxane 6 and cyclic siloxane 7 and 8 have been isolated and fully characterized.

Jack K. Crandall; Christophe Morel-Fourrier

1995-01-01

30

METAL BINDING IN SILOXANE-PHOSPHONATE POLYMERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The polymerization of di- and trialkoxysilanes using conventional sol-gel techniques produces two and three-dimensional siloxane networks. The hydrolysis and condensation result in the formation of an alcohol under mild conditions which can be removed under reduced pressure and moderate temperature...

31

Impressions of Leadership  

ERIC Educational Resources Information Center

I was early arriving for an appointment with the superintendent at the school where I would begin my first year as an elementary school principal. While I waited, I reflected on my first teaching job, where I had formed my first and most lasting impressions of leadership from the principal. Now it was my turn to be a principal, and I aspired to…

Smith, Agnes

2005-01-01

32

Virtual First Impressions  

ERIC Educational Resources Information Center

Frequently, a nurse's first and only contact with a graduate school, legislator, public health official, professional organization, or school nursing colleague is made through e-mail. The format, the content, and the appearance of the e-mail create a virtual first impression. Nurses can manage their image and the image of the profession by…

Bergren, Martha Dewey

2005-01-01

33

Forming impressions of personality  

Microsoft Academic Search

In a series of investigations, students were asked to form impressions and write brief characterizations of the person to whom a short list of trait adjectives applied. To facilitate evaluation, some groups of judges also rated the hypothetical person on a list of bipolar traits. It appears that traits may be central or peripheral, according to their fit in the

S. E. Asch

1946-01-01

34

Stereoregular Polyvinyl Nitrate.  

National Technical Information Service (NTIS)

Isotactic polyvinyl nitrate (PVN) was prepared to investigate the effect of stereorgularity on the physical properties of PVN. The isotatic PVN had a higher softening point and was more difficult to stabilize than regular PVN. (Author)

R. A. Strecker

1980-01-01

35

Siloxane treatment by adsorption into porous materials.  

PubMed

Siloxanes are widely used in different applications: health care, dry cleaning, household products, paints and coatings, paper, personal care, for example. This explains their prevalence in the environment. Because of their volatile nature, most of the time they are dispersed in the atmosphere, but they can also be present in the slurry from landfills. During anaerobic digestion, when the temperature goes up to 60 degrees C, siloxanes are volatilized, forming part of the biogas. Operational problems using biogas to produce energy, heat and hydrogen have been identified. At high temperatures the siloxanes are transformed into silicate dioxide (commonly called sand transmission). These white deposits may adhere to metal or catalytic substrate surfaces, seriously reducing equipment efficiency, and this can be a reason for changing equipment warranties. Consequently, elimination of siloxanes has become very important. Unfortunately, relatively little information can be found on this subject. Nevertheless some authors have described different analytical methods for siloxane quantification, and recent studies have looked at the presence of siloxanes in landfills and the restriction on the energy recovery equipment using the biogas produced. The growing consumption of siloxanes and silicones in industrial processes consequently increase their prevalence in the environment, hampering the use of biogas as a source of 'green energy'. Therefore, the principal focus of this study is the treatment of siloxanes. Their elimination was carried out using an adsorption process with four different porous materials: activated carbon cloths (ACC), granular activated carbon (GAC), zeolite and silica gel. Two representative siloxane compounds were used in this study, hexamethyldisiloxane (L2) and octamethylcyclotetrasiloxane (D4). Adsorption kinetics and isotherms in batch reactors were performed. It was observed that the mass transfer into the porous material was more rapid for the activated carbon than for the zeolite and silica gel, congruent with the porous structure of the material. Moreover, it was found that D4 is more adsorbable than L2, due to possible interactions between the solid surface and the physical structure of the cyclic compound (D4). The influence of humidity and temperature were also studied. The increase in the temperature reduced the adsorption capacities. The influence of humidity on the adsorption was investigated under dry air and humid air at 70%. No significant difference in the adsorption capacities was found for the activated carbon and for the zeolite, but for the silica gel the mass transfer decreased considerably. For the adsorption isotherms, the maximal capacity of elimination was obtained with the activated carbon materials and was directly related to the porous structure. Thus activated carbon cloth was chosen to design the adsorption-desorption processes in a dynamic system. Thermal heating was used to achieve the regeneration process. Initial cycles have been accomplished and show the stability of the process. PMID:19886432

Ricaurte Ortega, D; Subrenat, A

2009-09-01

36

New interpenetrating network type siloxane polymer electrolyte.  

SciTech Connect

An interpenetrating network (IPN), comb-type, siloxane-based solid polymer electrolyte solid polymer electrolyte was prepared and its electrochemical properties were evaluated. The cross-linking reaction conditions were established from accelerated rate calorimetry studies. An IPN solid ploymer electrolyte with 60 wt % of the comb-shaped siloxane showed an ionic conductivity of greater than 5x10{sup -4} S/cm at 37 C, with a wide electrochemical stability window of up to 4.5 V vs. lithium. A Li metal/solid polymer electrolyte/LiNi{sub 0.8}Co{sub 0.2}O{sub 2} cell showed promising discharge capacities above 130 mAh/g and good cycling performance.

Oh, B.; Hyung, Y.-E.; Vissers, D. R.; Amine, K.; Chemical Engineering

2002-11-01

37

Dielectric studies of a laterally-linked siloxane ester dimer  

Microsoft Academic Search

This paper reports measurements of the dielectric response over the frequency range 10 to 10?Hz of a liquid crystal dimer consisting of two ester mesogens laterally linked by an alkoxy chain containing a siloxane group. The synthesis and phase behaviour of the siloxane dimer are also reported. Results show that there are two relaxations in the isotropic phase and four

Sergio Diez; M. Rosario De La Fuente; Panagiota K. Karahaliou; Georg Mehl; Thomas Meyer; Miguel Ángel PerÉz Jubindo; Demetri J. Photinos

2003-01-01

38

Energy use of biogas hampered by the presence of siloxanes  

Microsoft Academic Search

Siloxanes are widely used in industrial processes and consumer products. Some of them reach the wastewater. Siloxanes are not decomposed in the activated sludge process and partly concentrate in the sludge. During anaerobic digestion of the sludge, they volatilise into the formed biogas. Combustion of silicon containing gases, e.g., when producing electricity, produces, however, the abrasive microcrystalline silica that has

Raf Dewil; Lise Appels; Jan Baeyens

2006-01-01

39

SOURCE ASSESSMENT: POLYVINYL CHLORIDE  

EPA Science Inventory

This report summarizes data on air emissions from the polyvinyl chloride (PVC) industry. PVC is manufactured by 20 companies at 35 plants. Each plant uses one or more of four possible polymerization processes: (1) suspension polymerization, (2) emulsion polymerization, (3) bulk p...

40

Making a Great First Impression  

ERIC Educational Resources Information Center

Managers and business owners often base hiring decisions on first impressions. That is why it is so important to teach students to make a great first impression--before they go on that first job interview. Managers do not have unrealistic expectations, they just want to hire people who they believe can develop into valuable employees. A nice…

Evenson, Renee

2007-01-01

41

Kinetic investigation of the solvation of lithium salts in siloxanes.  

SciTech Connect

The solvation of lithium salts in siloxanes was investigated with the aim to understand the key barriers that limit the ionic conductivity of siloxane-based electrolytes. The conductivity and kinetic data were measured for electrolytes with different salts, different salt concentrations, and solvents. The results show that both the conductivity and the kinetics of ionic transportation were greatly impacted by the specific interactions between ions and the solvent molecules. The high content of ion pairs in the electrolytes can be one of the main reasons for the low ionic conductivity observed in the siloxane-based electrolytes.

Chen, Z.; Wang, H. H.; Vissers, D. R.; Zhang, L.; West, R.; Lyons, L. J.; Amine, K.; Chemical Sciences and Engineering Division; Univ. of Wisconsin; Grinnell Coll.

2008-02-14

42

75 FR 61175 - Polyvinyl Alcohol From Taiwan  

Federal Register 2010, 2011, 2012, 2013

...731-TA-1088 (Final)] Polyvinyl Alcohol From Taiwan AGENCY: United...less-than-fair-value imports from Taiwan of polyvinyl alcohol, provided for in subheading...of Commerce that imports of polyvinyl alcohol from Taiwan are being sold...

2010-10-04

43

76 FR 13660 - Polyvinyl Alcohol From Taiwan  

Federal Register 2010, 2011, 2012, 2013

...731-TA-1088 (Final)] Polyvinyl Alcohol From Taiwan Determination On...reason of imports from Taiwan of polyvinyl alcohol, provided for under subheading...by Commerce that imports of polyvinyl alcohol from Taiwan were being...

2011-03-14

44

Characterization of Poly(Dimethyl Siloxane)-Polycarbonate Block Copolymers.  

National Technical Information Service (NTIS)

Shear modulus-temperature curves and swelling behavior of poly(dimethyl siloxane)-bisphenol-A polycarbonate block copolymers were studied. Two glass transitions corresponding to the silicone and polycarbonate phases are found. The dependence of one phase ...

M. Narkis A. V. Tobolsky

1969-01-01

45

PROPERTIES OF LITHIUM-DOPED SILOXANE-PHOSPHONATE CONDUCTING POLYMERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

A series of siloxane copolymers containing pendent phosphonate groups have been prepared and their electrochemical impedance tested. Condensation reactions between methoxy groups of the mononomers produced crosslinked films which were clear, colorless, and stable to air and moisture. The polymers ...

46

Ultra-High Molecular Weight Silphenylene-Siloxane Polymers.  

National Technical Information Service (NTIS)

Silphenylene-siloxane copolymers with molecular weights above one million were prepared using a two stage polymerization technique. The technique was successfully scaled up to produce 50 grams of this high polymer in a single run. The reactive monomer app...

W. J. Patterson N. H. Hundley L. M. Ludwick

1984-01-01

47

Enhancement of muddy footwear impressions.  

PubMed

Methods for chemical enhancement of muddy footwear impressions were compared in order to differentiate between utilisation at the scene of crime, the local (regional) police laboratory and the Netherlands Forensic Institute (NFI) PMID:11348794

Theeuwen, A B; van Barneveld, S; Drok, J W; Keereweer, I; Lesger, B; Limborgh, J C; Naber, W M; Schrok, R; Velders, T

2001-06-01

48

Enhancement of muddy footwear impressions  

Microsoft Academic Search

Methods for chemical enhancement of muddy footwear impressions were compared in order to differentiate between utilisation at the scene of crime, the local (regional) police laboratory and the Netherlands Forensic Institute (NFI)

A. B. E Theeuwen; S van Barneveld; J. W Drok; I Keereweer; B Lesger; J. C. M Limborgh; W. M Naber; R Schrok; T Velders

2001-01-01

49

Adsorption behavior of protein onto siloxane microspheres  

NASA Astrophysics Data System (ADS)

The siloxane microspheres with core-shell structure (PMMA/PMPS) (MMA, methyl methacrylate; MPS, 3-methacryloxypropyl-trimethoxysilane) have been prepared by dispersion polymerization as described in our previous work. In this paper, the developed poly(MMA-MPS) microspheres, as a carrier, are used to investigate the adsorption behavior of bovine serum albumin (BSA) on them. The Langmuir and Freundlich models have been applied to describe the adsorption behavior. The experimental results indicated that the presence of PMPS evidently increases the adsorption rate and the amount of protein, and it also influences the interaction of BSA molecules. The adsorption of BSA on the poly(MMA-MPS) microspheres seems to be sensitive to pH and ionic strength. The fittings curves from Langmuir and Freundlich models showed that the adsorption was actually more complicated than ideal situation because one or more interactions were involved in the process. For understanding the electronic contribution, the Zeta potential was used to measure the reactive system before and after protein adsorption.

Liu, Bailing; Cao, Shunsheng; Deng, Xiaobo; Li, Songjun; Luo, Rong

2006-09-01

50

Multimode siloxane polymer components for optical interconnects  

NASA Astrophysics Data System (ADS)

This paper presents an overview of multimode waveguides and waveguide components formed from siloxane polymer materials which are suitable for use in optical interconnection applications. The components can be cost-effectively integrated onto conventional PCBs and offer increased functionality in optical transmission. The multimode waveguides exhibit low loss (0.04 dB/cm at 850 nm) and low crosstalk (< -30 dB) performance, large alignment tolerances and negligible mode mixing for short waveguide lengths. Error-free data transmission at 10 Gb/s over 1.4 m long waveguides has been successfully demonstrated. Waveguide crossings exhibit very low excess losses, below 0.01 dB/crossing, and excellent crosstalk performance. Low loss is obtained for waveguide bends with radii of curvature larger than 8 mm and 6 mm for 90° and S-shaped bends respectively. High-uniformity splitting is achieved with multimode Y-splitters even in the presence of input misalignments. Y-combiners are shown to benefit from the multimode nature of the waveguides allowing low loss combining (4 dB for an 8×1 device). A large range of power splitting ratios between 30% and 75% is achieved with multimode coupler devices. Examples of system applications benefiting from the use of these components are briefly presented including a terabit capacity optical backplane, a radio-over-fibre multicasting system and a SCM passive optical network.

Bamiedakis, Nikolaos; Beals, Joseph, IV; Penty, Richard V.; White, Ian H.; Degroot, Jon V., Jr.; Clapp, Terry V.; de Shazer, David

2009-02-01

51

Maternal Imagination: Reconceiving First Impressions  

Microsoft Academic Search

The concept of maternal imagination, whereby the disordered thoughts and impressions of pregnant women are used to explain the prevalence of monstrous births, was at its height during the early modern period, albeit it with many prior and subsequent manifestations. Against a more familiar, and enduring, medieval and Renaissance context of supernatural agency at work, the device of MI was

Margrit Shildrick

2000-01-01

52

Salesperson impression and strategy formation  

Microsoft Academic Search

Personal selling is one of the most expensive, and for many companies, one of the most important elements of the marketing mix. Salesperson adaptivity is an especially important element of salesperson performance. The purpose of this research was to explore factors that may influence salespersons' adaptivity during the impression-formation and strategy formulation stages of the selling process. We found that

Elizabeth H. Creyer; William T. Ross

1994-01-01

53

Methyl modified siloxane melting gels for hydrophobic films  

Microsoft Academic Search

Hybrid melting gels were prepared by a sol–gel process, starting with a mono-substituted siloxane and a di-substituted siloxane.\\u000a Methyl-modified melting gels were prepared using (a) methyltriethoxysilane (MTES) with dimethyldiethoxysilane (DMDES) and\\u000a (b) methyltrimethoxysilane (MTMS) together with dimethyldimethoxysilane (DMDMS). The gels with MTES–DMDES were prepared with\\u000a concentrations between 50–50 and 75–25 mol%. The gels with MTMS–DMDMS were prepared with concentrations between 50–50

Andrei Jitianu; John Doyle; Glenn Amatucci; Lisa C. Klein

2010-01-01

54

The Preparation and Properties of D2-Carborane-Siloxanes.  

National Technical Information Service (NTIS)

The preparation of linear and amorphous D2-meta-carborane-siloxane polymers having molecular weights up to 250,000 by a new condensation process is described. These unique materials were compounded and vulcanized to give elastomers having outstanding rete...

E. N. Peters J. J. Bohan E. Hedaya J. H. Kawakami G. T. Kwiatkowski

1974-01-01

55

Diffusion of low molecular weight siloxane from bulk to surface  

Microsoft Academic Search

Silicone-based materials for outdoor insulators have the advantage that low molecular weight (LMW) components migrate through the material and coat the surface, thereby restoring hydrophobicity over a period of hours. By measuring the IR absorption of siloxane migrating to the silicone surface through a thin carbon coating, the time constant for migration was calculated. According to the time dependence of

H. Homma; T. Kuroyagi; K. Izumi; C. L. Mirley; J. Ronzello; S. A. Boggs

1999-01-01

56

Structure–gas transport property relationships of hexafluoroisopropylidene based poly(imide-siloxane)s  

Microsoft Academic Search

The gas permeation behaviour of three gases (N2, O2 and CO2) were studied through three different hexafluoroisopropylidene (6FDA) based novel poly(imide-siloxane) (PIS) membranes. The rigidity of the imide groups were varied by utilizing three different amines namely the flexible siloxane containing amine, diaminodiphenyl ether and diaminodiphenyl sulphone. The permeability value was found to be maximum for the more flexible siloxane

M. Srividhya; B. S. R. Reddy

2007-01-01

57

Siloxanes removal from biogas by high surface area adsorbents.  

PubMed

Biogas utilized for energy production needs to be free from organic silicon compounds, as their burning has damaging effects on turbines and engines; organic silicon compounds in the form of siloxanes can be found in biogas produced from urban wastes, due to their massive industrial use in synthetic product, such as cosmetics, detergents and paints. Siloxanes removal from biogas can be carried out by various methods (Mona, 2009; Ajhar et al., 2010 May; Schweigkofler and Niessner, 2001); aim of the present work is to find a single practical and economic way to drastically and simultaneously reduce both the hydrogen sulphide and the siloxanes concentration to less than 1ppm. Some commercial activated carbons previously selected (Monteleone et al., 2011) as being effective in hydrogen sulfide up taking have been tested in an adsorption measurement apparatus, by flowing the most volatile siloxane (hexamethyldisiloxane or L2) in a nitrogen stream, typically 100-200ppm L2 over N2, through an activated carbon powder bed; the adsorption process was analyzed by varying some experimental parameters (concentration, grain size, bed height). The best activated carbon shows an adsorption capacity of 0.1g L2 per gram of carbon. The next thermogravimetric analysis (TGA) confirms the capacity data obtained experimentally by the breakthrough curve tests. The capacity results depend on L2 concentration. A regenerative carbon process is then carried out by heating the carbon bed up to 200°C and flushing out the adsorbed L2 samples in a nitrogen stream in a three step heating procedure up to 200°C. The adsorption capacity is observed to degrade after cycling the samples through several adsorption-desorption cycles. PMID:24075968

Gislon, P; Galli, S; Monteleone, G

2013-09-26

58

Mass loading and fate of linear and cyclic siloxanes in a wastewater treatment plant in Greece.  

PubMed

The occurrence and fate of 5 cyclic (D3 to D7) and 12 linear (L3 to L14) siloxanes were investigated in raw and treated wastewater (both particulate and dissolved phases) as well as in sludge from a wastewater treatment plant (WWTP) in Athens, Greece. Cyclic and linear siloxanes (except for L3) were detected in all influent wastewater and sludge samples at mean concentrations of (sum of 17 siloxanes) 20 ?g L(-1) and 75 mg kg(-1), respectively. The predominant compounds in wastewater were L11 (24% of the total siloxane concentration), L10 (16%), and D5 (13%), and in sludge were D5 (20%) and L10 (15%). The distribution of siloxanes between particulate and dissolved phases in influents differed significantly for linear and cyclic siloxanes. Linear siloxanes showed higher solid-liquid distribution coefficients (log K(d)) than did cyclic compounds. For 10 of the 16 compounds detected in influents, the removal efficiency was higher than 80%. Sorption to sludge and biodegradation and/or volatilization losses are important factors that affect the fate of siloxanes in WWTPs. The mean total mass of siloxanes that enter into the WWTP via influent was 15.1 kg per day(-1), and the mean total mass released into the environment via effluent was 2.67 kg per day(-1). PMID:23320453

Bletsou, Anna A; Asimakopoulos, Alexandros G; Stasinakis, Athanasios S; Thomaidis, Nikolaos S; Kannan, Kurunthachalam

2013-01-30

59

Polyvinyl Esters of Omega-H-Perfluoroacids and Polyvinyl Alcohol Obtained from Them,  

National Technical Information Service (NTIS)

By means of radical polymerization at 20 we obtained polyvinyl esters of omega-H-perfluoroacids from monomers. The product of their saponification - polyvinyl alcohol (PVA) - differs significantly from PVA which is obtained by other methods (mainly with r...

Y. N. Rostovskiy L. D. Budovskaya

1987-01-01

60

Salience of Physical Appearance in Impression Formation  

Microsoft Academic Search

Descriptions of others often include an enumeration of their traits and it is char acteristic of people to form impressions of others based solely on these descrip tions. The present research assumed an analogy between these trait descriptions and various aspects of physical appearance which are known to generate such descriptions. Thus impression formation research on trait descriptions was used

Sharron J. Lennon; Franklin G. Miller

1984-01-01

61

The Role of Cosmetics in Impression Formation  

Microsoft Academic Search

The purpose of this research was to investigate the effect of cosmetics use on impression formation. The study was a single factor experiment with three levels of cosmetics (heavy, moderate, none). Eighty-five undergraduate females viewed one of three colored photographs of a professional model wearing either heavy, moderate, or no cosmetics and indicated impressions of her attractiveness, femininity, personal temperament,

Jane E. Workman; Kim K. P. Johnson

1991-01-01

62

First Impressions: The Factors of Influence  

Microsoft Academic Search

First impressions of women are formulated from observable characteristics that convey messages about their personality characteristics and demeanor. Hair, clothing, posture, smile and eye contact are a few examples of the factors that influence these perceptions. Impression management is important not only because judgments are made in a quick and permanent manner, but they may also affect the future of

Taylor Dury; Keith McGowan; Danika Kramer; Cassie Lovejoy; Diana Ries

2009-01-01

63

Are First Impressions Important in Academia?  

ERIC Educational Resources Information Center

Salary data from mathematicians and economists were used to test a model that first impressions of scholarly work are important to career success. Long-run salary increases from additional articles or citations decline with the age received. Large standard errors suggest that first impressions are not overly important. (Author/SK)

Siow, Aloysius

1991-01-01

64

Impression cytology in Down's syndrome  

PubMed Central

AIM—To evaluate both the number and the average distribution of goblet cells, which are responsible for the production of the mucin layer of the tear film, in the bulbar conjunctiva of patients with Down's syndrome. Previous research had used the ferning test to indicate an alteration in Down's syndrome, but had not determined which film layer was involved.?METHODS—The presence of goblet cells in the bulbar conjunctiva of 30 subjects (15 with Down's syndrome, and 15 normal control subjects) was evaluated using impression cytology.?RESULTS—A marked reduction of goblet cells was found in the Down's syndrome group (81.4 per mm2) when compared with the control group, where (209.8 per mm2) was found.?CONCLUSION—The deficit observed appears to be the cause of the tear film alterations observed in Down's syndrome. In turn, this may often lead to the formation of dry spots, and to consequent frequent infections of the anterior segment of the eye. While it is further hypothesised that the alteration of the conjunctival epithelium in Down's syndrome may be due to an altered metabolism of some element or elements, such as vitamin A, further research will be necessary to corroborate this.??

Filippello, M; Cascone, G; Zagami, A; Scimone, G

1997-01-01

65

The neural dynamics of updating person impressions.  

PubMed

Person perception is a dynamic, evolving process. Because other people are an endless source of social information, people need to update their impressions of others based upon new information. We devised an fMRI study to identify brain regions involved in updating impressions. Participants saw faces paired with valenced behavioral information and were asked to form impressions of these individuals. Each face was seen five times in a row, each time with a different behavioral description. Critically, for half of the faces the behaviors were evaluatively consistent, while for the other half they were inconsistent. In line with prior work, dorsomedial prefrontal cortex (dmPFC) was associated with forming impressions of individuals based on behavioral information. More importantly, a whole-brain analysis revealed a network of other regions associated with updating impressions of individuals who exhibited evaluatively inconsistent behaviors, including rostrolateral PFC, superior temporal sulcus, right inferior parietal lobule and posterior cingulate cortex. PMID:22490923

Mende-Siedlecki, Peter; Cai, Yang; Todorov, Alexander

2012-04-03

66

75 FR 15726 - Polyvinyl Alcohol From Taiwan; Determination  

Federal Register 2010, 2011, 2012, 2013

...Preliminary) (Remand)] Polyvinyl Alcohol From Taiwan; Determination...reason of imports from Taiwan of polyvinyl alcohol provided for in subheading 3905...of allegedly LTFV imports of polyvinyl alcohol from...

2010-03-30

67

76 FR 13982 - Antidumping Duty Order: Polyvinyl Alcohol From Taiwan  

Federal Register 2010, 2011, 2012, 2013

...A-583-841] Antidumping Duty Order: Polyvinyl Alcohol From Taiwan AGENCY: Import...an antidumping duty order on polyvinyl alcohol (PVA) from Taiwan. DATES...investigation of PVA from Taiwan. See Polyvinyl Alcohol From Taiwan: Final...

2011-03-15

68

21 CFR 177.1670 - Polyvinyl alcohol film.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 2013-04-01 false Polyvinyl alcohol film. 177.1670 Section 177.1670...Use Food Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact...

2013-04-01

69

21 CFR 177.1670 - Polyvinyl alcohol film.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2009-04-01 true Polyvinyl alcohol film. 177.1670 Section 177.1670...Use Food Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact...

2010-01-01

70

21 CFR 177.1670 - Polyvinyl alcohol film.  

Code of Federal Regulations, 2010 CFR

... 2009-04-01 2009-04-01 false Polyvinyl alcohol film. 177.1670 Section 177.1670...Use Food Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact...

2009-04-01

71

Miniemulsion copolymerization of methyl methacrylate and butyl acrylate in the presence of vinyl siloxane rubber  

Microsoft Academic Search

Vinyl siloxane rubber was successfully used as the co-stabilizer in the miniemulsion copolymerization of methyl methacrylate (MMA) and butyl acrylate (BA) initiated by ammonium persulfate. Effects of the molecular weight, vinyl content, and the amount of vinyl siloxane rubber on the kinetics and the particle morphology of the latex prepared were investigated. The rate of copolymerization was found to decrease

Zhang-Qing Yu; Pei-Hong Ni; Jie-Ai Li; Xiu-Lin Zhu

2004-01-01

72

Characterization of cholesteric cyclic siloxane liquid crystalline materials  

NASA Astrophysics Data System (ADS)

The preliminary investigation of a new type of a liquid crystalline material is described. These cyclic cholesteric siloxanes exhibit selective reflection which can be varied from the UV to the NIR by changing composition. DSC, TGA, SEK, TEM, UV-VIS-NIR spectroscopy, and polarized optical microscopy (POM) were used to obtain preliminary information on the thermal, optical, and macroscopic packing behavior as it related to possible optical applications of these materials. Considerable effort was also employed in examining the wide-angle and small-angle X-ray scattering (WAXS and SAXS) patterns obtained from these materials in a variety of forms including film, fiber, and powder samples.

Bunning, Timothy J.; Klei, Herbert E.; Samulski, Edward T.; Adams, W. W.; Crane, R. L.

1991-11-01

73

Development of novel cycloaliphatic siloxanes for thermal and UV-curable applications  

NASA Astrophysics Data System (ADS)

Siloxanes have been extensively used as additives to modulate surface properties such as surface tension, hydrophobicity/hydrophobicity, and adhesion, etc. Although, polydimethyl -siloxane and polydiphenylsiloxane are the most commonly used siloxanes, the properties are at extremes in terms of glass transition temperature and flexibility. It is proposed that the ability to control the properties in between the these extremes can be provided by cycloaliphatic substitutions at the siloxane backbone. It is expected that this substitution might work due to the intermediate backbone rigidity. In order to achieve the above objectives, a synthetic route was developed to prepare cycloaliphatic (cyclopentane and cyclohexane) silane monomers followed by subsequent polymerization and functionalizations to obtain glycidyl epoxy, aliphatic amine and methacrylate telechelic siloxanes. The siloxanes were either thermally or UV-cured depending on end functionalizations. Chemical characterization of monomers, oligomers and polymers were performed using 1H, 13C, 29Si-NMR, FT-IR and GPC. The curing kinetics of photo-induced reactions were investigated through photo-differential scanning calorimetry (PDSC). The oxygen permeability, mechanical, coatings, and release properties of siloxanes were studied as a function of the backbone substitutions. The mechanical, coatings and released properties of cycloaliphatic siloxanes improved with respect to polydimethylsiloxanes. The thermal analysis of the cured films were carried out using differential scanning calorimetry (DSC). Viscoelastic properties of the cured siloxanes due to the variation of substitution at the siloxane backbone were measured using dynamic mechanical thermal analysis (DMTA). The cycloaliphatic substituted siloxanes showed an increased glass transition temperature and permeability but reduced crosslink density, conversion, and rate of curing with respect to polydimethylsiloxanes. Hybrids of siloxanes were prepared with linseed oil based alkyds to study the effect of variation of alkyd oil lengths and cycloaliphatic substitutions on siloxane backbone. The oil length of an alkyd resin is defined as the number of grams of oil used to produce 100 grams of resin. Three linseed oil based alkyds representing long, medium, and short oil lengths were grafted with siloxanes substituted with methyl, cyclopentyl, and cyclohexyl groups. The reaction was monitored through FTIR and 1H-NMR. The hybrids were formulated with standard drier package and thermally cured for detailed film characterization. Improvement in crosslink density, flexibility, and reverse impact resistance were found as function of oil length. However, tensile modulus, elongation, glass transition temperature, drying time and fracture toughness decreased with increase in oil length. For hybrids, the cycloaliphatic substituents at the siloxane backbone showed enhanced mechanical and coating properties as compared to hybrids with polydimethylsiloxanes. Random and block copolymer of polydimethylsiloxanes with polydicycloaliphatic-siloxanes were synthesized and compared with homopolymers of polydicycloaliphatic siloxanes. The chemical characterization of the copolymers and homopolymers were carried out through 1H, 13C, 29Si-NMR, and FT-IR. The glass transition temperatures (Tg) of the synthesized polymers were obtained through DSC and advanced rheometric expansion system (ARES). The Tg of random copolymers were found to be higher than the corresponding block copolymers. There was very small difference in T g between cycloaliphaticsiloxanes homopolymers and corresponding random copolymers. From the above results, it can be inferred that the cycloaliphatic substitutions at the siloxane backbone can be used as a means to obtain properties intermediate to polydimethyl- and polydiphenyl siloxanes.

Chakraborty, Ruby

74

Shark fin test and impression quality: A correlation analysis  

Microsoft Academic Search

ObjectivesTo evaluate the correlation between the shark fin test and the dimensional accuracy of impressions, surface detail reproduction of impressions and rheological properties of impression materials within the manufacturer's recommended working time.

Markus Balkenhol; Bernd Wöstmann; Masafumi Kanehira; Werner J. Finger

2007-01-01

75

Enhancement of footwear impressions in blood  

Microsoft Academic Search

Methods for chemical enhancement of footwear impressions in blood were compared in order to make a separation between utilization at the scene of crime, the local (regional) police laboratory and the Dutch Forensic Science Laboratory (DFSL).

A. B. E Theeuwen; S van Barneveld; J. W Drok; I Keereweer; J. C. M Limborgh; W. M Naber; T Velders

1998-01-01

76

Enhancement of footwear impressions in blood.  

PubMed

Methods for chemical enhancement of footwear impressions in blood were compared in order to make a separation between utilization at the scene of crime, the local (regional) police laboratory and the Dutch Forensic Science Laboratory (DFSL). PMID:9722976

Theeuwen, A B; van Barneveld, S; Drok, J W; Keereweer, I; Limborgh, J C; Naber, W M; Velders, T

1998-07-20

77

First Impressions of the Comet Drilling Problem.  

National Technical Information Service (NTIS)

Preliminary impressions gained from the workshop by someone with no prior knowledge of comets or space technology are presented. Ideas on the composition and density of comet material are suggested as needing refinement in order to give the drill designer...

M. Mellor

1989-01-01

78

First Impressions of Eastern European Education.  

ERIC Educational Resources Information Center

Describes the first impressions of a high school teacher on her first day of teaching conversational English at a secondary school in Budapest, Hungary. Notes the great variation in students' English language skills. (RS)

Spoleti, Linda Higgins

1995-01-01

79

21 CFR 872.3660 - Impression material.  

Code of Federal Regulations, 2013 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3660 Impression material. (a) Identification...provide models for study and for production of restorative prosthetic devices, such as gold inlays and dentures. (b)...

2013-04-01

80

Police uniform color and citizen impression formation  

Microsoft Academic Search

Clothing color and style are significant factors in impression formation in first-time dealings with strangers. Four common\\u000a police uniform color schemes are evaluated for their influence on seven scales of impression formation with a sample of 737\\u000a citizens in a Midwestern city. Consistent with the previous literature, the all black color scheme was viewed most negatively\\u000a on six of the

Richard R. Johnson

2005-01-01

81

Polyvinyl alcohol hydrogels for iontohporesis  

NASA Astrophysics Data System (ADS)

Transdermal therapeutic systems propound controlled release of active ingredients through the skin into the systemic circulation in a predictive manner. Drugs administered through these systems escape first-pass metabolism and maintain a steady state scenario similar to a continuous intravenous infusion for up to several days. The iontophoresis deal with the systemic delivery of the bioactive agents (drug) by applying an electric current. It is basically an injection without the needle. The iontophoretic system requires a gel-based matrix to accommodate the bioactive agent. Hydrogels have been used by many investigators in controlled-release drug delivery systems because of their good tissue compatibility and easy manipulation of swelling level and, thereby, solute permeability. In this work we have prepared polyvinyl alcohol (PVA) hydrogel. We have cross linked polyvinyl alcohol chemically with Glutaraldehyde with different wt%. FTIR study reveals the chemical changes during cross linking. Swelling in water, is done to have an idea about drug loading and drug release from the membrane. After drug loading to the hydrogels, we have studied the drug release property of the hydrogels using salicylic acid as a model drug.

Bera, Prasanta; Alam, Asif Ali; Arora, Neha; Tibarewala, Dewaki Nandan; Basak, Piyali

2013-06-01

82

Carbonate-modified siloxanes as solvents of electrolyte solutions for rechargeable lithium cells  

Microsoft Academic Search

Influence of mixing carbonate-modified siloxanes into LiPF6-ethylene carbonate (EC)\\/ethylmethyl carbonate (EMC) (mixing volume ratio=3:7) mixed solvent electrolytes on charge–discharge cycling properties of lithium was examined. As the solute, 1M (M: molL?1) LiPF6 was used. As siloxanes, 4-(2-trimethylsilyloxydimethylsilylethyl)-1,3-dioxolan-2-one and 4-(2-bis(trimethylsilyloxy)methylsilylethyl)-1,3-dioxolan-2-one were investigated. These siloxanes are derivatives of butylene cyclic carbonate or vinyl ethylene carbonate. Charge–discharge cycling efficiencies of lithium metal anodes

Takashi Takeuchi; Satoshi Noguchi; Hideyuki Morimoto; Shin-ichi Tobishima

2010-01-01

83

Assessing the clarity of friction ridge impressions.  

PubMed

The ability of friction ridge examiners to correctly discern and make use of the ridges and associated features in finger or palm impressions is limited by clarity. The clarity of an impression relates to the examiner's confidence that the presence, absence, and attributes of features can be correctly discerned. Despite the importance of clarity in the examination process, there have not previously been standard methods for assessing clarity in friction ridge impressions. We introduce a process for annotation, analysis, and interchange of friction ridge clarity information that can be applied to latent or exemplar impressions. This paper: (1) describes a method for evaluating the clarity of friction ridge impressions by using color-coded annotations that can be used by examiners or automated systems; (2) discusses algorithms for overall clarity metrics based on manual or automated clarity annotation; and (3) defines a method of quantifying the correspondence of clarity when comparing a pair of friction ridge images, based on clarity annotation and resulting metrics. Different uses of this approach include examiner interchange of data, quality assurance, metrics, and as an aid in automated fingerprint matching. PMID:23313600

Hicklin, R Austin; Buscaglia, JoAnn; Roberts, Maria Antonia

2013-01-10

84

Giving the wrong impression: food and beverage brand impressions delivered to youth through popular movies  

PubMed Central

Background Marketing on television showcases less-healthful options, with emerging research suggesting movies promote similar products. Given the obesity epidemic, understanding advertising to youth should be a public health imperative. The objective of this study was to estimate youth impressions to food and beverages delivered through movies. Methods Impressions were calculated by dividing US receipts annually into average movie ticket prices, then multiplying this by the number of brand appearances. Examination by ratings, product types and ages were conducted by Spearman rank correlation coefficient tests. Results Youth in the USA saw over 3 billion food, beverage or food–retail establishment (FRE) impressions on average, annually from 1996 to 2005. Those aged 12–18 viewed over half of all impressions, with PG-13-rated movies containing 61.5% of impressions. There were no significant trends in brand appearances by food, beverage or FRE impressions over the decade, although there was a decreasing trend in R-rated impressions for both foods (P< 0.01) and beverages (P< 0.01), but not FREs (P= 0.08). Conclusions Movies promote billions of food and beverage impressions annually to youth. Given the public health crisis of obesity, future research should further investigate these trends, as well as the potential association of these unhealthy exposures in youth.

Skatrud-Mickelson, Monica; Adachi-Mejia, Anna M.; MacKenzie, Todd A.; Sutherland, Lisa A.

2012-01-01

85

Experienced and inexperienced counselors' first impressions of clients and case outcomes: Are first impressions lasting?  

Microsoft Academic Search

Investigated whether or not counselors' 1st interview impressions were related to case outcomes among experienced and inexperienced counselors. 1st-impression variables included intensity of client concern, client physical attractiveness, ease with which the client expressed himself, assessment of the client's potential for change, and the counselor's personal liking for the client. Some variables were significantly related to the number of counseling

Robert D. Brown

1970-01-01

86

Cognitive representation of personality impressions: Organizational processes in first impression formation  

Microsoft Academic Search

In 3 experiments with a total of 186 graduate and undergraduate students, Ss given either impression formation (IF) or memory task (MT) instructions read a series of behavior descriptions that either did or did not contain a highly distinctive item. In each study, IF Ss recalled significantly more items than did MT Ss. Ss given impression formation instructions were more

David L. Hamilton; Lawrence B. Katz; Von O. Leirer

1980-01-01

87

Quantitative estimation method for discrimination of nuance among impression words  

Microsoft Academic Search

In this paper the authors discuss a quantitative estimation method for discrimination of nuance among impression words that express favor, impression feeling, emotion, or aesthetic sense. The impression words play the role of keywords on information retrieval for the database of fine arts or industrial design. The subtle discrimination among the nuance of impression words makes verbal expression of our

S. Taka Gi; Y. Isomoto; H. Nozaki

2000-01-01

88

Social Psychological Models of Impression Formation among Consumers  

Microsoft Academic Search

Three different perspectives on the formation of product impressions among consumers were compared: the adding model of impression formation, the averaging model of impression formation, and attribution theory. These three models lead to mutually exclusive predictions regarding the results of information processing and impression formation among consumers. One hundred thirty-four subjects participated in three studies which compared the accuracy of

Brian Mullen

1984-01-01

89

Impression management training: Conceptualization and application to personal selling  

Microsoft Academic Search

This article addresses the need for knowledge about impression management as a communication phenomenon in the training industry. The article discusses the importance of impression management, as a communicative phenomenon, in a variety of real?world contexts, provides a comprehensive conceptualization of the impression management process, and demonstrates how this conceptualization of the impression management process can facilitate effective training of

Dale G. Leathers

1988-01-01

90

Accuracy of three implant impression techniques with different impression materials and stones.  

PubMed

The purpose of this study was to compare the accuracy of casts made using three different impression techniques to obtain an accurate definitive cast for fabrication of multiple-implant prostheses. Twelve experimental groups were formed combining the following conditions: three impression techniques, two impression materials, and two cast materials. The main effects of the three factors were analyzed by three-way analysis of variance using the full factorial general linear model between factors. The results showed that there were no significant differences in mean values for the transferred dimensions between the control and experimental groups. None of the measurements in the horizontal plane of the definitive casts demonstrated significant differences among the impression techniques with different impression and cast materials (P > .01). PMID:22259795

Chang, Won-Gun; Vahidi, Farhad; Bae, Kwang-Hak; Lim, Bum-Soon

91

Structure-property relationships in silica-siloxane nanocomposite materials  

SciTech Connect

The simultaneous formation of a filler phase and a polymer matrix via in situ sol-gel techniques provides silica-siloxane nanocomposite materials of high strength. This study concentrates on the effects of temperature and relative humidity on a trimodal polymer system in an attempt to accelerate the reaction as well as evaluate subtle process- structure-property relations. It was found that successful process acceleration is only viable for high humidity systems when using the tin(IV) catalyst dibutyltin dilaurate. Processes involving low humidity were found to be very temperature and time dependent. Bimodal systems were investigated and demonstrated that the presence of a short-chain component led to enhanced material strength. This part of the study also revealed a link between the particle size and population density and the optimization of material properties.

Ulibarri, T.A.; Derzon, D.K.; Wang, L.C.

1997-03-01

92

Termite Resistance of Polyvinyl Chloride Plastics.  

National Technical Information Service (NTIS)

A project for determining the nature of termite attack upon polymeric materials is in progress. Thirty-two formulations containing polyvinyl chloride resin were prepared incorporating, variously, four plasticizers, three insecticides and two degrees of ha...

J. D. Bultman J. M. Leonard C. R. Southwell

1966-01-01

93

Primary Plasticizers for Poly(Vinyl Chloride).  

National Technical Information Service (NTIS)

According to the patent application, acetal derivatives of polyunsaturated fatty compositions were prepared and found to function as primary plasticizers. Poly(vinyl chloride) resins plasticized by the compositions of this application have properties equa...

R. A. Awl E. H. Pryde

1974-01-01

94

Electrophoresis in Polyvinyl-Alcohol Gel.  

National Technical Information Service (NTIS)

It was found that electrophoresis in polyvinyl-alcohol, although not completely equivalent to that in polyacrylamide, is entirely possible and can accordingly be employed as an alternative method in certain cases, e.g. difficulties of procurement of polya...

C. Reich H. Sieber

1967-01-01

95

Gas transport properties of segmented poly(ether siloxane urethane urea) membranes  

Microsoft Academic Search

Poly(ether siloxane urethane urea) with different polysiloxane contents were synthesized and characterized. The single gas permeation properties of poly(ether siloxane urethane urea) membranes were determined at 30°C for O2, N2, CO2, CH4, n-C4H10. Their structures and gas permeation properties were compared. Significant correlation among the polysiloxane soft segment with the permeation properties was found. In addition, an analysis of the

D. Gomes; K.-V. Peinemann; S. P. Nunes; W. Kujawski; J. Kozakiewicz

2006-01-01

96

Permeation of Substituted Silanes and Siloxanes Through Selected Gloves and Protective Clothing  

Microsoft Academic Search

Testing of the permeation resistance of eight glove and suit barriers against commercially available substituted silanes and siloxanes was performed using the ASTM F739–96 standard test method. In addition to barrier performance to the pure organosilanes, the permeation rates of the hydrolysis product (usually ethanol or methanol) were investigated. The silanes and siloxanes used as the challenge agents were N-2-(aminoethyl)-3-aminopropyltrimethoxysilane;

Gary O. Nelson; Stephen J. Priante; Michael Strong; Dennis Anderson; Jeanne Fallon-Carine

2000-01-01

97

Photo-Reactive Polyimides and Poly(siloxane imide)s as Reversible Polymeric Interfaces  

Microsoft Academic Search

Polyimides and poly(siloxane imide)s containing photo-active cyclobutane diimide units were developed as reversible adhesives for temporary bonding in micro-fabrication processes. Poly(amic acid) formation in dipolar aprotic solvents and subsequent chemical or thermal solution imidization yielded the corresponding organic soluble polyimides. Incorporation of nonplanar (alicyclic or bicyclic) structures and poly(dimethyl siloxane) blocks into the main chain improved the solubility. The synthesized

Stephen M. June; Takeo Suga; William H. Heath; Timothy E. Long; Qin Lin; Rama Puligadda

2010-01-01

98

Functionalized siloxane-based polymers and network materials for second-order nonlinear optics  

Microsoft Academic Search

We have developed a new chemical methodology, based on simple acid-base hydrolysis of aminosilanes with molecules containing terminal OH groups, to prepare robust siloxane based polymers and organic-inorganic hybrid network materials for second-order nonlinear optics. First, a variety of polymers containing NLO- active chromophores covalently bound to the siloxane backbones, [-R2Si-(O- SiR2)n-O-(NLO-Chromophore)-O-] n (R = CH3 or CH3\\/C6H4) and [-

Hongwei Jiang

1999-01-01

99

Survey of Organosilicone Compounds, Including Cyclic and Linear Siloxanes, in Personal-Care and Household Products  

Microsoft Academic Search

The determination of organosiloxanes in consumer products is important for the evaluation and characterization of sources\\u000a of human and environmental exposures. In this study, we determined concentrations of cyclic siloxanes [octamethylcyclotetrasiloxane\\u000a (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6)], tetradecamethylcycloheptasiloxane (D7)] and linear siloxanes (L4 to L14) in a variety of consumer products (n = 76), including hair-care products, skin lotions, body washes, cosmetics, nursing

Yuichi Horii; Kurunthachalam Kannan

2008-01-01

100

Interpersonal Teaching Style and Student Impression Formation  

ERIC Educational Resources Information Center

Assuming that learning is an inherently social process, this research explores interpersonal variables that affect teaching. Specifically, does the interpersonal teaching style affect student impressions of the instructor? Eighty-five undergraduates viewed one of three ten-minute videos that portrayed either an authoritarian, authoritative, or…

Coldren, Jeffrey; Hively, Jodi

2009-01-01

101

Ultrasound influence on impression evaluation of music  

Microsoft Academic Search

We have investigated whether ultrasound changes our audible impressions when we listen to music or not. To solve this question, we verify that there might be a mechanism perceiving ultrasound by a physiological pre-experiment, and review discrepancy in subjective estimations for two kinds of sounds played back with and without ultrasound by a psychological experiment. In this paper, we study

Masakazu Higuchi; Mitsuteru Nakamura; Yasuhiro Toraichi; Kazuo Toraichi; Yasuo Morooka; Kazuki Katagishi; Nobuyuki Otsu; Hitomi Murakami

2009-01-01

102

A neural mechanism of first impressions  

Microsoft Academic Search

Evaluating social others requires processing complex information. Nevertheless, we can rapidly form an opinion of an individual during an initial encounter. Moreover, people can vary in these opinions, even though the same information is provided. We investigated the brain mechanisms that give rise to the impressions that are formed on meeting a new person. Neuroimaging revealed that responses in the

Jonathan B Freeman; Jason P Mitchell; James S Uleman; Daniela Schiller; Elizabeth A Phelps

2009-01-01

103

Are First Impressions Important in Academia?  

Microsoft Academic Search

This paper demonstrates that the popular belief that first impressions are important in determining career success is theoretically sound. The model is then tested with salary data on mathematicians and economists. In general, the point estimates show that the long run increase in salary from an additional article or citation declines with the age at which it is received. The

Aloysius Siow

1991-01-01

104

Handshaking, gender, personality, and first impressions  

Microsoft Academic Search

Although people's handshakes are thought to reflect their personality and influence our first impressions of them, these relations have seldom been formalLy investigated. One hundred twelve participants had their hand shaken twice by 4 trained coders (2 men and 2 women) and completed 4 personality measures. The participants' handshakes were stable and consistent across time and coders. There were also

William F. Chaplin; Jeffrey B. Phillips; Jonathan D. Brown; Nancy R. Clanton; Jennifer L. Stein

2000-01-01

105

Magnetite anodes for impressed current cathodic protection  

Microsoft Academic Search

Magnetite anodes for impressed current cathodic protection, when constructed according to the design by Paul Bergsoee and Son A.B., overcome certain inherent disadvantages of magnetite (magnetic iron oxide) to afford low consumption at high current loads. More than 30,000 Bera Magnetite anodes have been put into operation. The anode is cast as an open cylinder with one end closed, approximately

1978-01-01

106

Irradiation of polyvinyl alcohol and polyvinyl pyrrolidone blended hydrogel for wound dressing  

Microsoft Academic Search

Polyvinyl alcohol and polyvinyl pyrrolidone (PVA–PVP) blended hydrogel for wound dressing has been prepared by using gamma rays irradiation technique. The gel fraction, mechanical properties, the water content and water absorption performance of the hydrogels were measured. It was found that the gel fraction increases with increasing irradiation dose but never reaches 100% of gel. The PVA\\/PVP blended hydrogel has

Mirzan T Razzak; Darmawan Darwis; Zainuddin; Sukirno

2001-01-01

107

The effect of polyvinyl alcohol and polyvinyl pyrrolidone on diffusion artifacts in lactate dehydrogenase histochemistry  

Microsoft Academic Search

The effect of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), alone and in combination, on diffusion artifacts in histochemical incubations has been investigated using LDH as model enzyme. By measuring the amount of formazan in the medium at the end of the incubation it has been shown that both substances, but especially PVA, are effective in limiting diffusion. The significance

Hans A. Dahl; Svein Ivar Mellgren

1970-01-01

108

Polyvinyl Alcohol Cross-Linked with 2 Aldehydes.  

National Technical Information Service (NTIS)

A film-forming polyvinyl alcohol resin is admixed, in aqueous solution, with a dialdehyde crosslinking agent which is capable of crosslinking the polyvinyl alcohol resin and a water soluble acid aldehyde containing a reactive aldehyde group capable of rea...

D. W. Sheibley L. L. Rieker L. C. Hsu M. A. Manzo

1982-01-01

109

Leaf Impressions: A Model for Carbonization  

NSDL National Science Digital Library

In this activity students make leaf impressions on paper to illustrate how carbonization works. They use the leaf press method to demonstrate staining as a model for carbonization, when living tissue leaves a carbon film in sediment and rock. The students will discover that many plant fossils are preserved through carbonization and that soft parts of animals including skin and fur have also been preserved as fossils through the process of carbonization.

Greb, Stephen

110

Junge relationships in measurement data for cyclic siloxanes in air.  

PubMed

In 1974, Junge postulated a relationship between variability of concentrations of gases in air at remote locations and their atmospheric residence time, and this Junge relationship has subsequently been observed empirically for a range of trace gases. Here, we analyze two previously-published datasets of concentrations of cyclic volatile methyl siloxanes (cVMS) in air and find Junge relationships in both. The first dataset is a time series of concentrations of decamethylcyclopentasiloxane (D5) measured between January and June, 2009 at a rural site in southern Sweden that shows a Junge relationship in the temporal variability of the measurements. The second dataset consists of measurements of hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4) and D5 made simultaneously at 12 sites in the Global Atmospheric Passive Sampling (GAPS) network that shows a Junge relationship in the spatial variability of the three cVMS congeners. We use the Junge relationship for the GAPS dataset to estimate atmospheric lifetimes of dodecamethylcyclohexasiloxane (D6), 8:2-fluorotelomer alcohol and trichlorinated biphenyls that are within a factor of 3 of estimates based on degradation rate constants for reaction with hydroxyl radical determined in laboratory studies. PMID:23177712

Macleod, Matthew; Kierkegaard, Amelie; Genualdi, Susie; Harner, Tom; Scheringer, Martin

2012-11-21

111

A novel chemically selective siloxane polymer for chemical vapor sensing  

NASA Astrophysics Data System (ADS)

A new hydrogen-bond acidic carbosiloxane polymer for quartz crystal microbalance sensors (QCMs) application was synthesized via O-alkylation, Claisen rearrange, hydrosilylation reaction and functionalized the polysiloxane with trifluoroacetone groups (TFA). The trifluoroisopropanol functionalized polysiloxane was characterized by FT-IR and 1HNMR. And this novel siloxane polymer was coated onto AT-cut 8 MHz QCM sensors to investigate its gas sensitive responses to the organophosphorus nerve agent stimulant dimethyl methylphosphonate (DMMP) vapor as well as other interfering organic vapors. The research work indicated that frequency shifts of the trifluoroisopropanol functionalized polysiloxane based QCM sensor to the DMMP vapor were completely linear, and with a regression coefficient of 0.9973 in the concentration range of 10-60 ppm. In addition, the sensitivity of the fabricated QCM sensors to DMMP was up to 10.64 Hz/ ppm, and much higher than the other interfering vapors, limits of detection (LODs) of the QCM sensors was 0.28 ppm, thus high selectivity to DMMP was demonstrated in this work.

Huang, Jia; Jiang, Yadong; Du, Xiaosong; Bi, Juan

2010-05-01

112

Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test.  

PubMed

Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane. PMID:23684695

Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

2013-05-16

113

Radiolysis of tetrazolium salts in polyvinyl alcohol  

SciTech Connect

The radiation chemical yields of formazans were measured in binary systems containing polyvinyl alcohol and tetrazolium salts as additives; it was established that they are more than half of the yields of radicals in pure polyvinyl alcohol. The ESR spectra of the indicated systems were measured at various temperatures, and the relative changes in the radical concentrations were determined. It was suggested that the increase in the concentration of single radicals at T > 400 K is due to the participation of radical pairs in the reaction. 15 refs., 4 figs., 1 tab.

Kriminskaya, Z.K.; Ginzburg, S.F.; Molin, A.A.

1992-01-01

114

Polyvinyl alcohol battery separator containing inert filler  

SciTech Connect

A cross-linked polyvinyl alcohol battery separator is disclosed. A particulate filler, inert to alkaline electrolyte of an alkaline battery, is incorporated in the separator in an amount of 1-20% by weight, based on the weight of the polyvinyl alcohol, and is dispersed throughout the product. Incorporation of the filler enhences performance and increases cycle life of alkaline batteries when compared with batteries containing a similar separator not containing filler. Suitable fillers include titanates, silicates, zirconates, aluminates, wood floor, lignin, and titania. Particle size is not greater than about 50 microns.

Sheibley, D.W.; Hsu, L.C.; Manzo, M.A.

1981-06-01

115

Cross-Linked Polyvinyl Alcohol and Method of Making Same.  

National Technical Information Service (NTIS)

A method is described for producing cross-linked polyvinyl alcohol battery separators. A film-forming polyvinyl alcohol resin is admixed, in aqueous solution, with a dialdehyde cross-linking agent which is capable of cross-linking the polyvinyl alcohol re...

D. W. Sheibley L. L. Rieker L. C. Hsu M. A. Manzo

1981-01-01

116

Auditory and visual spatial impression: Recent studies of three auditoria  

Microsoft Academic Search

Auditory spatial impression is widely studied for its contribution to auditorium acoustical quality. By contrast, visual spatial impression in auditoria has received relatively little attention in formal studies. This paper reports results from a series of experiments investigating the auditory and visual spatial impression of concert auditoria. For auditory stimuli, a fragment of an anechoic recording of orchestral music was

Andy Nguyen; Densil Cabrera

2004-01-01

117

Auditory Versus Visual Spatial Impression: A Study of Two Auditoria  

Microsoft Academic Search

Spatial impression refers to the attributes of subjective space beyond localization. In the field of auditorium acoustics, auditory spatial impression is often divided into 'apparent source width', 'envelopment' and sometimes 'intimacy'. In separate experiments, this study considers how visual and auditory spatial impression vary within two auditoria, and hence similarities between these two sensory modes. In the visual experiment, the

Densil Cabrera; Andy Nguyen; Young-ji Choi

2004-01-01

118

Faceplant: Impression (Mis)management in Facebook Status Updates  

Microsoft Academic Search

While recent research examined the impressions projected by users of Social Network Sites through their relatively static online profiles, the addition of status updates to Facebook offers the opportunity to study a more fluid type of impression management. In this paper, we take a first look at data collected with a custom application designed to capture the impressions both \\

Vladimir Barash; Nicolas Ducheneaut; Ellen Isaacs; Victoria Bellotti

119

Faceplant: Impression (Mis)management in Facebook Status Updates  

Microsoft Academic Search

While recent research examined the impressions projected by users of Social Network Sites through their relatively static online profiles, the addition of status updates to Facebook offers the opportunity to study a more fluid type of impression management. In this paper, we take a first look at data collected with a custom application designed to capture the impressions both \\

Vladimir Barash; Nicolas Ducheneaut; Ellen Isaacs; Victoria Bellotti

2010-01-01

120

Impression Management Training: Conceptualization and Application to Personal Selling.  

ERIC Educational Resources Information Center

Discusses the importance of impression management, an individual's conscious attempt to exercise control over selected communicative behaviors and cues for purposes of making a desired impression. Provides a comprehensive conceptualization of the impression-management process, and demonstrates how this process can facilitate effective training of…

Leathers, Dale G.

1988-01-01

121

Determination of siloxanes and VOC in landfill gas and sewage gas by canister sampling and GC-MS\\/AES analysis  

Microsoft Academic Search

Biogases such as landfill gas and sewage gas undergo a combustion process which is generating electric energy. Since several trace compounds such as siloxanes (also halogenated and sulfur compounds) are known to cause severe problems to these gas combustion engines, they are of particular interest. In this work, a new technique for sampling, identification, and quantification of siloxanes and volatile

Martin Schweigkofler; Reinhard Niessner

1999-01-01

122

Quantitative and high mass ToF-SIMS studies of siloxane segregation in hydrogel polymers using cryogenic sample handling techniques  

Microsoft Academic Search

This paper examines the capabilities of cryogenic sample handling to examine composition and structure of hydrogel materials where siloxane components are central to the analysis. XPS analysis of multicomponent polymers with cryogenic sample handling following exposure to aqueous environments has revealed the composition and kinetics of near surface reorganization for siloxane and fluorocarbon containing polymers. In this study we report

Daniel J. Hook; Paul L. Valint; Lu Chen; Joseph A. Gardella

2006-01-01

123

Polyvinyl Alcohol Particle Size and Suspension Characteristics  

Microsoft Academic Search

PURPOSE: To evaluate the size and shape of commercially available polyvinyl alcohol (PVA) particles and to determine whether they change in size when suspended in nonionic contrast and in a solution of nonionic contrast and absolute alcohol. METHODS: The two-dimensional area and the long and short axis of PVA particles from several different vendors were measured using a light microscope

Colin P. Derdeyn; Christopher J. Moran; DeWitte T. Cross; Hans H. Dietrich; Ralph G. Dacey

124

Sisal cellulose whiskers reinforced polyvinyl acetate nanocomposites  

Microsoft Academic Search

Sisal nanowhiskers were used as novel reinforcement to obtain nanocomposites with polyvinyl acetate (PVAc) as matrix phase. They are seen as attractive materials due to the widespread availability and low cost of the sisal source material. Statistical analysis of the sisal whisker length and diameter resulted in average values of 250 nm and 4 nm, respectively, resulting in an average aspect ratio

Nancy Lis Garcia de Rodriguez; Wim Thielemans; Alain Dufresne

2006-01-01

125

Endgroup-assisted siloxane bond cleavage in the gas phase.  

PubMed

Unimolecular dissociation of H(2)N(CH(2))(3)SiOSi(CH(2))(3)NH(3)(+) generates SiC(5)H(16)NO(+) and SiC(5)H(14)N(+). The formation of SiC(5)H(16)NO(+) involves dissociation of a Si[bond]O bond and formation of an O[bond]H bond through rearrangement. The fragmentation mechanism was investigated utilizing ab initio calculations and Fourier transform ion cyclotron resonance (FTICR) mass spectrometry in combination with hydrogen/deuterium (H/D) exchange reactions. Sustained off-resonance irradiation collision-induced dissociation (SORI-CID) studies of the fully deuterated ion D(2)N(CH(2))(3)SiOSi(CH(2))(3)ND(3)(+) provided convincing evidence for a backbiting mechanism which involves hydrogen transfer from the terminal amine group to the oxygen to form a silanol-containing species. Theoretical calculations indicated decomposition of H(2)N(CH(2))(3)SiOSi(CH(2))(3)NH(3)(+) through a backbiting mechanism is the lowest energy decomposition channel, compared with other alternative routes. Two mechanisms were proposed for the fragmentation process which leads to the siloxane bond cleavage and the SORI-CID results of partially deuterated precursor ions suggest both mechanisms should be operative. Rearrangement to yield a silanol-containing product ion requires end groups possessing a labile hydrogen atom. Decomposition of disiloxane ions with end groups lacking labile hydrogen atoms yielded product ions from direct bond cleavages. PMID:12954172

Chen, Huiping

2003-09-01

126

Assessment of tissue conditioning materials for functional impressions.  

PubMed

The validity of two types of tissue conditioning materials was studied and compared with that of two commonly used impression materials. The effect of three important factors on the accuracy of the impressions was observed. These factors were thickness of the impression material, time of compression of the impression, and the time interval before pouring the impression. A chrome-cobalt master cast was specially designed and 500 impressions were made and poured, resulting in 900 casts. Conclusions reached from this investigation were that: 1. Visco-Gel and Coe-Comfort tissue conditioning materials can be used as impression materials. 2. The dimensional accuracy of Visco-Gel is better than that of the Coe-Comfort impressions. 3. There is no significant difference between using a tray with a space of 1.5 mm or 3.0 mm for the impression material. 4. The less bulky the impression, the less time is required for compression with fewer inaccuracies. 5. It is preferable to pour the cast in the impression immediately or within 2 hours. 6. Both kinds of materials tested can be used as duplicating materials under certain conditions. PMID:290790

Razek, M K

1979-10-01

127

Physician relationships: make your first impression count.  

PubMed

Strategies for physician recruitment should include the following: Consider creating an in-house recruiting system to save money and to "own" the health system's first impression. Gain a competitive advantage by nurturing relationships with prospects over the long-term. Use innovative recruitment techniques, such as video interviewing and electronic reference checking, to better coordinate recruitment, follow-up, and mentoring. Make a new hire's job satisfaction and home life a top priority during the first 90 days of employment, and then plan regular follow-ups to maintain a positive relationship. PMID:22616516

Crepeau, Jason

2012-05-01

128

Malleability of social impressions of hyperactive children.  

PubMed

The role of adults' social cognitions in mediating judgments of hyperactive children's medication-related behavior change was explored. Two hundred eight-eight undergraduates observed two videotaped excerpts of a hyperactive "target" boy playing a group game with two peers. Each target was taking either methylphenidate (0.6 mg/kg) during both excerpts, placebo during both excerpts, methylphenidate first followed by placebo, or placebo first followed by methylphenidate. Adults' cumulative social evaluations of the child were assessed after they viewed both video segments. Results indicated that observers combined their perceptions of the two behavior samples into composite impressions using an equal-weight averaging algorithm. Even for children whose behavior improved, adults' ratings of undercontrolled behaviors continued to meet or, in some cases exceed, research cutoff scores used to identify hyperactive children. The findings suggest that the actual behaviors of children with attention-deficit hyperactivity disorder (ADHD) play a more influential role in shaping interpersonal impressions than do perceiver social-cognitive processes such as primacy, recency, or integration biases. PMID:8126317

Granger, D A; Whalen, C K; Henker, B

1993-12-01

129

First Impressions Versus Good Impressions: The Effect of Self-Regulation on Interview Evaluations  

Microsoft Academic Search

Self-regulation may interfere with the ability to fully use situational information to form impressions of others. The demands posed by self-regulation were studied in a job interview situation. In the context of a simulated job interview, participants in the high cognitive load condition (interviewers) were less able to correct their initial characterizations of a job applicant with situational information than

Cynthia R. Nordstrom; Rosalie J. Hall; Lynn K. Bartels

1998-01-01

130

Making the Right Impression: A Field Study of Applicant Impression Management During Job Interviews  

Microsoft Academic Search

Two issues were explored: (a) which impression management (IM) tactics applicants use during actual interviews and (b) whether there is a relationship between applicants' IM tactics and their interview outcomes. The study also examined convergence across different methods and raters when measuring IM. Postinterview survey measures were obtained from applicants and interviewers regarding applicant IM behavior during a specific interview;

Cynthia Kay Stevens; Amy L. Kristof

1995-01-01

131

Synthesis, NMR (Nuclear Magnetic Resonance) Characterization and Electrical Properties of Siloxane- Based Polymer Electrolytes.  

National Technical Information Service (NTIS)

A crosslinked siloxane-based polymer has been prepared by the reaction of Poly(methylhudrosiloxane), monomethyl ether poly(ethylene glycol), and poly(ethylene glycol). The polymer, which has been structurally characterized by 29 Si NMR, forms complexes wi...

R. Spindler D. F. Shriver

1987-01-01

132

Damage Mechanisms of Filled Siloxanes for Predictive Multiscale Modeling of Aging Behavior  

Microsoft Academic Search

Predictions of component performance versus lifetime are often risky for complex materials in which there may be many underlying aging or degradation mechanisms. In order to develop more accurate predictive models for silica-filled siloxane components, we are studying damage mechanisms over a broad range of size domains, linked together through several modeling efforts. Atomistic and molecular dynamic modeling has elucidated

B Balazs; R Maxwell; S de Teresa; L Dinh; R Gee

2002-01-01

133

New Polysaccharide-based Microparticles Crosslinked with Siloxane: Interactions with Biologically Active Substances  

Microsoft Academic Search

The interaction of microparticles of carboxymethyl pullulan crosslinked with siloxane (provided by a new crosslinking agent: 3-(glycid oxypropyl) trimethoxysilane) with biologically active molecules, such as enzymes (lysozyme) and drugs (propranolol, quinidine) was studied. The anionic amphiphilic supports retained through electrostatic and\\/or hydrophobic forces, variable amounts of the substances as a function of their structure, such as crosslinking degree and amount

Georgeta Mocanu; Doina Mihai; Mélanie Legros; Luc Picton; Didier Lecerf

2008-01-01

134

Glucose permeable poly (dimethyl siloxane) poly ( N-isopropyl acrylamide) interpenetrating networks as ophthalmic biomaterials  

Microsoft Academic Search

Poly (dimethyl siloxane) (PDMS) has been widely used as a biomaterial in ophthalmic and other applications due to its good compatibility, high mechanical strength, excellent oxygen permeability and transparency. However, for use as an artificial cornea, contact lens and in other applications, modifications with hydrophilic functional groups or polymers are necessary to improve wettability for tear protein and mucin interactions

L Liu; H Sheardown

2005-01-01

135

The Effect of Surface Siloxane Layers on the Penetration of Hydrogen into Iron  

Microsoft Academic Search

In acid and weakly alkaline media, including those containing hydrogenation promoters, mono- and polymolecular siloxanes layers applied to iron inhibit both the summary cathodic process and the penetration of hydrogen into the metal, provided the structure and thickness of the layers have been controlled by properly chosen adsorption conditions and the chemical nature of the starting silane. In varying the

M. A. Petrunin; L. B. Maksaeva; A. I. Marshakov

2001-01-01

136

Study of zwitterionic sulfopropylbetaine containing reactive siloxanes for application in antibacterial materials  

Microsoft Academic Search

Antibacterial agents receive a great deal of attention around the world due to the interesting academic problems of how to combat bacteria and of the beneficial health, social and economic effects of successful agents. Scientists are actively developing new antibacterial agents for biomaterial applications. This paper reports the novel antibacterial agent siloxane sulfopropylbetaine (SSPB), which contains reactive alkoxysilane groups. The

Shiguo Chen; Shaojun Chen; Song Jiang; Yangmiao Mo; Junxuan Luo; Jiaoning Tang; Zaochuan Ge

2011-01-01

137

Radiographic aspects of office hysteroscopic tubal occlusion with siloxane intratubal devices (the Ovabloc® method)  

Microsoft Academic Search

Objective: To evaluate the importance of radiographs in women sterilized with hysteroscopically applied siloxane intratubal devices (ITDs). Methods: A retrospective study of the frequency of abnormal radiographs in 500 women was carried out. The agreement in judging these radiographs and the expected reliability of the sterilization was measured. Results: Abnormal radiographs were mostly documented in the first 100 sterilization procedures.

G van der Leij; F. B Lammes

1997-01-01

138

Reaction of Organoaluminum Compounds with Organo(Poly)Siloxanes, Alkylaluminum Silanolates.  

National Technical Information Service (NTIS)

Organo(poly)siloxanes readily react with aluminum alkyls, e.g., with triethylaluminum (AlR(sub 3)), at elevated temperatures, with cleavage of the otherwise very stable Si-O-Si bond to form the so far unknown alkylaluminum silanolates. The behavior of the...

H. Jenkner

1989-01-01

139

Formation of bubbles during ultrasonic treatment of cured poly(dimethyl siloxane)  

Microsoft Academic Search

A static ultrasonic treatment device was used to investigate the effect of ultrasound on degradation of unfilled poly(dimethyl siloxane) (PDMS) vulcanizate in the absence of shearing effect. The effects of pressure, ultrasound intensity and thickness of the disks upon ultrasonic treatment were investigated. The power consumption was measured as a function of sample thickness, ultrasonic amplitude, and applied pressure. The

Sang Eun Shim; Sayata Ghose; Avraam I Isayev

2002-01-01

140

First impressions of the comet drilling problem  

NASA Astrophysics Data System (ADS)

Preliminary impressions gained from the workshop by someone with no prior knowledge of comets or space technology are presented. Ideas on the composition and density of comet material are suggested as needing refinement in order to give the drill designer a fair chance of success. Comments on the subsurface sampling, power allocation, static force and torque for drilling, design limits for drilling rate, materials for cutting tools clearing drill cuttings, anchoring the lander, positioning the core drill, inertial drilling systems and testing are given. The influence of the drilling and sampling needs on the basic design of the lander and return capsule are called into question. A warning of possible flaws in the comments due to insufficient understanding of the problem is given.

Mellor, Malcom

1989-12-01

141

[Impression traces from firearms on cadaver skin].  

PubMed

Guns may occasionally leave traces on human skin, for example by compression/impression of the tissue (esp. in the area of livores), by contact-transfer of dirt, oil, and rust, or by forming the pattern of blood-smears. The case of a 31-year-old drug-addict is presented in detail: The man committed suicide by shooting himself (entrance hole under the chin). When the dead body was found there was no weapon at the scene. By careful securing of evidence and analyzing the pattern of metallisations (identified as rust from the old pistol) it was reconstructed that the suicident held the pistol (identified as Russian Tokarew TT33-7.62 mm) in his hand for many hours postmortem until it was removed by an unknown thief. PMID:8687278

Püschel, K; Koops, E; Kulle, K J

142

Titration of free hydroxyl and strained siloxane sites on silicon dioxide with fluorescent probes.  

PubMed

A technique enabling the detection and quantification of low density sites on planar SiO2 surfaces is demonstrated. Fluorescent probes are used to titrate free hydroxyl and strained siloxane sites on the surface of amorphous SiO2 substrates in vacuum. The titration of free hydroxyl sites was performed to validate the method and to provide a reference for the measurement of the strained siloxane site density. Perylene derivatives with different functional groups are chemisorbed onto the surface sites, enabling in situ photoluminescence (PL) measurements of the bound fluorophores. An amine functional group is used to selectively titrate strained siloxane sites, while an alcohol group is used for the titration of free hydroxyl sites. Emission intensity was found to be nonlinear with coverage for bound fluorophore densities greater than 0.1 nm(-2), necessitating the removal of molecules from the surface into a solution to obtain accurate density measurements. For lower densities, the coverage of bound fluorophores can be estimated directly from in situ PL measurements. The measured areal densities of bound fluorophores after titrating free hydroxyl sites are in good agreement with literature values for the densities of such sites on high surface area silica. PL measurements of SiO2 surfaces titrated with an amine derivative of perylene indicate that strained siloxane sites exist for vacuum pretreatment temperatures of 300 °C and increase with increasing pretreatment temperature. Densities of strained siloxane sites on the silica surface are estimated at 0.004-0.02 nm(-2) for pretreatment temperatures of 300-700 °C, demonstrating the sensitivity of this technique. PMID:23978272

McCrate, Joseph M; Ekerdt, John G

2013-09-11

143

Gender Differences in Impression Management in Organizations: A Qualitative Review  

Microsoft Academic Search

In this article we review the literature on impression management to determine if there are substantial gender differences\\u000a in the employment of impression management tactics in organizational contexts. Based on a social roles theory perspective\\u000a (Eagly, 1987), we examined use of impression management tactics in organizational settings for gender differences in behavior.\\u000a We expected that men and women would generally

Rosanna E. Guadagno; Robert B. Cialdini

2007-01-01

144

Hydrophilicity of elastomeric non-aqueous impression materials during setting  

Microsoft Academic Search

Objectives. Clinically relevant accuracy of dental impressions depends on flowing and wetting properties of the applied impression materials. The major objective of this study was to develop an experimental set-up and an analysis strategy for wettability measurements of impression materials during their working time.Methods. High-resolution drop shape analysis was used to study contact angles on thin unset films of two

Frank Rupp; Detlef Axmann; Anne Jacobi; Martin Groten; Jürgen Geis-Gerstorfer

2005-01-01

145

The fungicidal effect of ultraviolet light on impression materials  

SciTech Connect

The effects of ultraviolet (UV) light on fungi and impression materials were tested. UV light (250 microW/cm2) killed most Candida organisms (10(3) cells/ml) within 5 minutes. UV light (8000 microW/cm2) killed most C. albicans (10(7) cells/ml) within 2 minutes of exposure. The effect of UV light on dimensional change and surface roughness of impression materials (irreversible hydrocolloid, agar, and silicone rubber) was tested. The results showed that neither dimensional change nor surface roughness of the impression materials were affected. The results of this study indicate that UV light disinfects impression materials that are contaminated with Candida organisms.

Ishida, H.; Nahara, Y.; Tamamoto, M.; Hamada, T. (Department of Prosthetic Dentistry, Hiroshima University, School of Dentistry (Japan))

1991-04-01

146

Nonverbal cues-based first impressions: Impression formation through exposure to static images  

Microsoft Academic Search

Consumers often make judgments about service providers based solely on their photograph (e.g., on a billboard, on the Internet)\\u000a before interacting with them face-to-face. This first impression is important for marketers to understand because it influences\\u000a service provider selection and evaluation. This research explores the nature and subsequent influence of initial judgments\\u000a made from static images. The results of two

Rebecca Walker Naylor

2007-01-01

147

Pyrolytic carbon membranes containing silica derived from poly(imide siloxane): the effect of siloxane chain length on gas transport behavior and a study on the separation of mixed gases  

Microsoft Academic Search

Poly(imide siloxane) (PIS) precursors have been synthesized in different compositions and appraised in their ability to form carbon membranes containing silica (C–SiO2). During inert pyrolysis, the imide domains in the PIS were transformed into a carbon-rich phase conferring a molecular sieving capability for molecular pairs of small gases, such as H2\\/N2, He\\/N2, CO2\\/N2, and O2\\/N2. The siloxane domains in the

Ho Bum Park; Chul Ho Jung; Youn Kook Kim; Sang Yong Nam; Sun Yong Lee; Young Moo Lee

2004-01-01

148

Effects of Music on Image Impression and Relationship between Impression and Physical Properties  

NASA Astrophysics Data System (ADS)

Auditory information plays an integral role in AV media because even identical images are perceived differently when they are matched with different music. However, we now present a few studies in which the changes in subjective perceptions were analyzed on the basis of the physical properties of the perceived items. The purpose of this study is to investigate the effects of music on image impression in terms of the physical properties of images. In this paper, we first elucidate the changes in subjective impressions when the image is presented by itself and when it is presented with music. Secondly, to clarify the relation between the impression of an image or music and physical properties, we compare the different image or music perceptions with each other and also compare their respective physical properties, which include color information, structural information, and frequency characteristics. As a result, the color information of an image containing green or saturation colors and the power of the music were strongly correlated with adjectives expressing activity. Moreover, the entropy of saturation correlated with words expressing spatial extent.

Sato, Keiko; Mitsukura, Yasue

149

40 CFR 61.64 - Emission standard for polyvinyl chloride plants.  

Code of Federal Regulations, 2013 CFR

...for polyvinyl chloride dispersion resins, excluding latex...stripper(s)] for dispersion polyvinyl chloride resins...determined on a dry solids basis; (ii) 0...chloride product for dispersion polyvinyl chloride resins...determined on a dry solids basis. (ii)...

2013-07-01

150

76 FR 5562 - Polyvinyl Alcohol From Taiwan: Final Determination of Sales at Less Than Fair Value  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Final Determination...has determined that imports of polyvinyl alcohol (PVA) from Taiwan are being...antidumping duty investigation of polyvinyl alcohol from Taiwan. See...

2011-02-01

151

78 FR 39256 - Polyvinyl Alcohol From Taiwan: Rescission of Antidumping Duty Administrative Review; 2012-2013  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Rescission of...the antidumping duty order on polyvinyl alcohol (PVA) from Taiwan for the...CCPC to the Department, ``Polyvinyl Alcohol from Taiwan: Withdrawal...

2013-07-01

152

75 FR 38079 - Postponement of Preliminary Determination of Antidumping Duty Investigation: Polyvinyl Alcohol...  

Federal Register 2010, 2011, 2012, 2013

...Antidumping Duty Investigation: Polyvinyl Alcohol From Taiwan AGENCY: Import...antidumping duty investigation on polyvinyl alcohol from Taiwan. See Initiation...Anti-Dumping Duty Investigation: Polyvinyl Alcohol From Taiwan, 69 FR...

2010-07-01

153

78 FR 20890 - Polyvinyl Alcohol From Taiwan: Preliminary Results of Antidumping Duty Administrative Review...  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Preliminary Results...the antidumping duty order on polyvinyl alcohol (PVA) from Taiwan. The period...Duty Administrative Review: Polyvinyl Alcohol from Taiwan;...

2013-04-08

154

THE INFLUENCE OF CLOTHING COLOR ON ATTRACTION AND IMPRESSION FORMATION  

Microsoft Academic Search

Previous research has shown that clothing is an important determinant of an individual's initial impression of a stranger. Color is a readily perceived feature of clothing, and thus may be one dimension of attire that contributes to the impression conveyed by the wearer. Using the premises of attraction theory and the findings of investigations concerning color meaning and affect, it

BARBARA A. VALOVAGE YENER

1982-01-01

155

Accuracy of casts generated from dual-arch impressions  

Microsoft Academic Search

Statement of problem. Dual-arch trays are often used to make simultaneous impressions of a prepared tooth and the opposing teeth. Many dentists are concerned with the accuracy of the casts generated from this type of impression. Purpose. The purpose of this investigation was to compare the accuracy of stone casts of a prepared tooth generated using 2 types of dual-arch

Larry C. Breeding; Donna L. Dixon

2000-01-01

156

A Cybernetic Model of Impression Management Processes in Organizations  

Microsoft Academic Search

Recent theory and research have suggested that a significant portion of human behavior in organizations is motivated by impression management concerns, that is, by the desire to be perceived by others in certain ways. However, the complex interpersonal dynamics of impression management in organizations remain largely unexplored. This paper synthesizes theory and research across several disciplines and literatures to present

Dennis P. Bozeman; K. Michele Kacmar

1997-01-01

157

Contamination level of alginate impressions arriving at a dental laboratory  

Microsoft Academic Search

The contamination level of alginate impressions delivered to a large dental laboratory in Sweden was determined. One hundred and seven consecutive alginate impressions were included during 7 days. Samples were taken and transferred into sterile physiological saline and analysed microbiologically for colony-forming units (cfu) as well as nonhemolytic, !-hemolytic, and #-hemolytic colonies. After sampling, the clinics were contacted and asked

A. Sofou; T. Larsen; N.-E. Fiehn; B. Öwall

2002-01-01

158

Country music as impression management: A meditation on fabricating authenticity  

Microsoft Academic Search

Without using Goffman's well-known theory of impression management in any conscious way, Richard Peterson, in his Creating country music: Fabricating authenticity (1997), demonstrated that impression management was a central process in creating country music. The present study explicitly links Peterson's ideas about the fabrication of authenticity to Goffman's Presentation of self in everyday life (1959) in an attempt to show

Michael Hughes

2000-01-01

159

>Cognitive complexity and impression formation in informal social interaction  

Microsoft Academic Search

While awaiting the arrival of the experimenter, pairs of subjects participated in ten minutes of spontaneous casual interaction. The impression which each formed of the other was assessed. Analyses of these impressions compared subjects differing in initial level of cognitive complexity. High complexity subjects, in comparison with noncomplex subjects, formed more differentiated, more abstract, more highly organized, and less evaluatively

Jesse G. Delia; Ruth Anne Clark; David E. Switzer

1974-01-01

160

Person Perception and Children's Impressions of Television and Real Peers  

Microsoft Academic Search

Much television programming depicts people engaged in social interaction. Children's understandings of television, therefore, may be guided by their abilities to make sense of character depictions. By examining the developmental characteristics of impressions, this study suggests that the same construal process shapes children's understandings of both television and real peers. The study also indicates that impressions of both television and

AUSTIN S. BABROW; BARBARA J. OKEEFE; DAVID L. SWANSON; RENEE A. MEYERS; MARY A. MURPHY

1988-01-01

161

Individual differences in judgmental tendencies derived from first impressions  

Microsoft Academic Search

This report introduces the First Impression Interaction Procedure (FIIP) as a new method of assessing participant initial reactions to unfamiliar partners encountered during 25-min uncontrolled interaction sessions. The 14-item FIIP rating form quantifies first impression central tendency (Judgment Index), variability (Judgment Variability Index), and the degree to which participants judged others more harshly than self (Judgment Ratio). Selected participants can

Alan R King; Allison N Pate

2002-01-01

162

Interviewers’ Sensitivity to Impression Management Tactics in Structured Interviews  

Microsoft Academic Search

This study examines interviewers’ sensitivity to impression management in structured interviews by determining the relative importance that interviewers attach to (verbal and nonverbal) impression management as compared to the relative importance that they attach to predetermined competencies. Two samples of interviewers (55 Master I\\/O psychology students and 18 professional interviewers) watched and evaluated videotaped interviewees who were instructed to put

Filip Lievens; Helga Peeters

2008-01-01

163

Affect and Impression Formation: Influence of Mood on Person Memory  

Microsoft Academic Search

Two experiments were conducted to examine the effects of mood on person memory. Subjects in a happy, sad, or neutral mood read impression congruent, incongruent, and irrelevant behavioral information about a target person and were later asked to recall as many of the behaviors as they could. In both experiments, only Ss in a neutral mood recalled impression-incongruent information at

Arlene G. Asuncion; Winnie F. Lam

1995-01-01

164

Using double-poured alginate impressions to fabricate bleaching trays.  

PubMed

Esthetic and diagnostic treatment often requires two casts of one arch, one for baseline and one for alterations (diagnostic wax-up, bleaching tray, occlusal analysis). The purpose of this study was to compare the accuracy of stone casts generated from a second pour of a properly handled alginate impression with first-poured casts. A maxillary dentoform was indexed with six reference spaces (#8-15, 9-2, 2-15, and incisal-to-gingival of #3, 9, 14). Irreversible hydrocolloid (Jeltrate) impressions were made in perforated steel trays by a single investigator. Impression material was spatulated for 1 minute. The seated impression and dentoform were wrapped in a damp paper towel to simulate intraoral conditions, and allowed to set for 2 minutes. Upon separation, the impression was stored in a damp towel for 5 minutes. The impression was poured in cast stone (Microstone) according to the manufacturer's instructions. The stone-filled impression was immediately rewrapped in a damp paper towel and allowed to set for 45 minutes at room temperature. Upon removal of the stone, the impression was rinsed with cold water, shaken dry, and repoured in the same manner. Ten impressions were made: the first five impressions were poured to make casts for Group A, then repoured as described above for casts for Group B. The remaining five impressions were poured once to make casts for Group C. The six spaces of each cast were measured three times in random order using a dial caliper and the space average calculated for the cast. At each space, analysis of variance showed no significant difference among Groups A, B, or C (P < 0.05). When alginate impressions that have been poured with cast stone are kept moist during stone setting and repoured within 45 minutes, two casts can be generated from one impression with the same degree of accuracy as two casts made from taking two separate impressions, providing the alginate does not tear during first cast removal. PMID:9656923

Haywood, V B; Powe, A

165

Conjunctival impression cytology: bright hope of children.  

PubMed

A practical method of screening for pre-clinical xerophthalmia due to vitamin A deficiency, called conjunctival impression cytology (CIC), is described as it is being used in a training stage in the Philippines. The noninvasive technic consists of touching the conjunctiva with a filter paper disc, and fixing and staining the disc on a slide for histology. Normally goblet cells with mucin spots are seen among sheets of epithelial cells. In abnormal conjunctiva from vitamin A deficient individuals, the epithelial cells are enlarged, and goblet cells are lacking. These specimens may be obtained from areas of the conjunctiva that appear clinically normal. The equipment needed is millipore paper, a hand-held suction pump with 5 feet of tubing, tissue or gauze, screw-top vials, labels, fixative, Papanicolaou stain, and a microscope. Vitamin A supplements can be given to affected children, or to the whole population at risk. With CIC training materials donated by International Center for Epidemiologic and Preventive Ophthalmology (ICEPO) at the Wilmer Institute, and the School of Hygiene and Public Health of the Johns Hopkins University, Baltimore, the 1st training class was certified by the Nutrition Center of the Philippines. Twice yearly training of physicians and technologists has been recommended. PMID:12284665

166

Survey of Cyclic and Linear Siloxanes in Sediment from the Songhua River and in Sewage Sludge from Wastewater Treatment Plants, Northeastern China  

Microsoft Academic Search

Siloxanes are used in a wide range of industrial applications, such as fuel additives, automotive polishes and waxes, and\\u000a antifoaming agents, as well as in personal care products and biomedical devices. Despite the potential for environmental occurrence,\\u000a few studies have reported sources and pathways of siloxanes in the environment. In this study, we determined concentrations\\u000a of four cyclic siloxanes, namely,

Zifeng ZhangHong; Hong Qi; Nanqi Ren; Yifan Li; Dawen Gao; Kurunthachalam Kannan

2011-01-01

167

Complex compound polyvinyl alcohol-titanic acid/titanium dioxide  

NASA Astrophysics Data System (ADS)

A complex compound polyvinyl alcohol-titanic acid has been produced and investigated by means of IR and Raman spectroscopy, X-ray diffraction, and synchronous thermal analysis. It is claimed that it represents an interpolymeric complex of polyvinyl alcohol and hydrated titanium oxide.

Prosanov, I. Yu.

2013-02-01

168

Polylactic acid\\/cellulose whisker nanocomposites modified by polyvinyl alcohol  

Microsoft Academic Search

The aim of this study was to produce biodegradable polylactic acid\\/cellulose whisker nanocomposites by compounding extrusion and investigate the possibility to use polyvinyl alcohol to improve the dispersion of whiskers in the matrix. Two feeding methods of polyvinyl alcohol and cellulose nanowhiskers were used and evaluated, dry-mixing with polylactic acid prior extrusion or pumping as suspension directly into the extruder.

Daniel Bondeson; Kristiina Oksman

2007-01-01

169

Preparation and characterization of core\\/shell particles with siloxane in the shell  

Microsoft Academic Search

The core\\/shell particles consisting of polystyrene core and 3-(methacryloxypropyl)-trimethoxysilane (MPS) shell were prepared in the present study by successive seeding polymerization under kinetically controlled conditions and were characterized by particle size analyser, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The TEM image indicated that the particles containing organic siloxane presented an evident core\\/shell structure. Additionally, the study of

Bailing Liu; Xiaobo Deng; Shunsheng Cao; Songjun Li; Rong Luo

2006-01-01

170

Separator grafted with siloxane by electron beam irradiation for lithium secondary batteries  

Microsoft Academic Search

Polyethylene (PE) separator grafted with 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (siloxane) was newly prepared by electron beam irradiation. The degree of grafting and morphology of the grafted separators were characterized by FT-IR and scanning electron microscopy (SEM). The polymer electrolytes based on the grafted separators were prepared by immersing the separators in the electrolyte containing 1M LiPF6 in EC\\/DMC (1:1 by volume). The ionic

Jun Young Lee; Yong Min Lee; Bhaskar Bhattacharya; Young-Chang Nho; Jung-Ki Park

2009-01-01

171

Weathering characteristics of wood treated with water glass, siloxane or DMDHEU  

Microsoft Academic Search

Specimens of Scots pine sapwood (Pinus sylvestris) and beech wood (Fagus sylvatica) were treated with a sodium water glass solution, an amino-alkyl-functional oligomeric siloxane and 1,3-dimethylol-4,5-dihydroxyethylene\\u000a urea (DMDHEU). The specimens were exposed outside without ground contact for 24 months. Colour measurements during outside\\u000a exposure showed a discoloration of all wood specimen surfaces. FTIR spectroscopy displayed lignin degradation of all specimens

Antje Pfeffer; Carsten Mai; Holger Militz

172

Controlled stepwise growth of siloxane chains using bivalent building units with different functionalities  

Microsoft Academic Search

Organic\\/inorganic hybrids of silicon and their subsequent chemical modification are of interest for tailoring and structuring surfaces on the nanoscale. The formation of organic (sub)monolayers on hydroxylated silicon surfaces was employed to synthesize molecular siloxane chains by stepwise wet-chemical condensation reactions. Functionalizations with small alkyl-monochlorosilanes, yielding dimethylsilyl, diisopropylsilyl, di-tert-butylsilyl terminations, and with an aryl-monochlorosilane, providing diphenylsilyl groups, were studied. The

Nils Salingue; Dominic Lingenfelser; Pavel Prunici; Peter Hess

2010-01-01

173

Perylenediimide functionalized bridged-siloxane nanoparticles for bulk heterojunction organic photovoltaics  

NASA Astrophysics Data System (ADS)

Perylenediimide functionalized bridged siloxane nanoparticles were prepared by direct hydrolysis and condensation of a perylenediimide silane precursor in the presence of a catalytic amount of tetraethoxysilane (TEOS). The sizes of the particles were controlled by adjusting organotrialkoxysilane, base, and TEOS concentrations. Using this modified Stöber method, we were able to incorporate a higher load of organic content (~70%) into the siloxane core compared to typical organically modified Stöber silica nanoparticles. The size, shape, and surface morphology of these functionalized particles were visualized using transmission electron microscopy. Their compositions were confirmed by FTIR, thermogravimetric analysis, and elemental analysis. The photovoltaic performance of these nanohybrids in the poly(3-hexylthiophene) polymer matrix was evaluated. The device made from a sample annealed at 150 °C showed reasonably good photovoltaic performance with a power conversion efficiency of 1.56% under standard test conditions of AM 1.5G spectra at an illumination intensity of 100 mW cm-2.Perylenediimide functionalized bridged siloxane nanoparticles were prepared by direct hydrolysis and condensation of a perylenediimide silane precursor in the presence of a catalytic amount of tetraethoxysilane (TEOS). The sizes of the particles were controlled by adjusting organotrialkoxysilane, base, and TEOS concentrations. Using this modified Stöber method, we were able to incorporate a higher load of organic content (~70%) into the siloxane core compared to typical organically modified Stöber silica nanoparticles. The size, shape, and surface morphology of these functionalized particles were visualized using transmission electron microscopy. Their compositions were confirmed by FTIR, thermogravimetric analysis, and elemental analysis. The photovoltaic performance of these nanohybrids in the poly(3-hexylthiophene) polymer matrix was evaluated. The device made from a sample annealed at 150 °C showed reasonably good photovoltaic performance with a power conversion efficiency of 1.56% under standard test conditions of AM 1.5G spectra at an illumination intensity of 100 mW cm-2. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr30538k

Rathnayake, Hemali; Binion, Jenna; McKee, Aaron; Scardino, Debra Jo; Hammer, Nathan I.

2012-07-01

174

NHC-catalyzed dehydrogenative self-coupling of diphenylsilane: A facile synthesis of octaphenylcyclotetra(siloxane)  

PubMed Central

A unique application of the CuIPr N-heterocyclic carbene (NHC) to the dehydrogenative self-coupling of diphenylsilane has been discovered. This transformation is carried out open to air at room temperature, yielding octaphenylcyclotetra(siloxane) quantitatively in one hour. This preparation constitutes a significant improvement over existing methods for the preparation of this compound and demonstrates a novel mode of reactivity for CuIPr. The diphenylsilanone tetramer is the precursor to a number of industrially significant polymers.

Albright, Abigail; Gawley, Robert E.

2011-01-01

175

New copolyimide membranes with high siloxane content designed to remove polar organics from water by pervaporation  

Microsoft Academic Search

The syntheses of oligodimethylsiloxane film forming materials and their organoselective properties for the removal of ethanol and phenol from water by pervaporation are reported. Two series of segmented polydimethylsiloxane-imide (PSI) copolymers were synthesized from ?,?-(bisaminopropyl) dimethylsiloxane oligomers (ODMS) and aromatic dianhydrides (PMDA, 6FDA); synthesized PSI were obtained with a high content of siloxane block, i.e. up to 94wt.%. To improve

M Krea; D Roizard; N Moulai-Mostefa; D Sacco

2004-01-01

176

Social Relevance Enhances Memory for Impressions in Older Adults  

PubMed Central

Previous research has demonstrated that older adults have difficulty retrieving contextual material over items alone. Recent research suggests this deficit can be reduced by adding emotional context, allowing for the possibility that memory for social impressions may show less age-related decline than memory for other types of contextual information. Two studies investigated how orienting to social or self-relevant aspects of information contributed to the learning and retrieval of impressions in young and older adults. Participants encoded impressions of others in conditions varying in the use of self-reference (Experiment 1) and interpersonal meaningfulness (Experiment 2), and completed memory tasks requiring the retrieval of specific traits. For both experiments, age groups remembered similar numbers of impressions. In Experiment 1, using more self-relevant encoding contexts increased memory for impressions over orienting to stimuli in a non-social way, regardless of age. In Experiment 2, older adults had enhanced memory for impressions presented in an interpersonally meaningful relative to a personally irrelevant way, whereas young adults were unaffected by this manipulation. The results provide evidence that increasing social relevance ameliorates age differences in memory for impressions, and enhances older adults’ ability to successfully retrieve contextual information.

Cassidy, Brittany S.; Gutchess, Angela H.

2012-01-01

177

Nonlinear optical (NLO) and luminescent properties of hybrid siloxane-oxide coatings  

NASA Astrophysics Data System (ADS)

Poled hybrid siloxane-oxide coatings synthesized through hydrolysis and condensation of Si(OMe)4 and TDSP precursors leads to SHG values of 10 pm/V. The glass transition temperatures of the hybrid coatings increase with the TMOS content and the thermal curing time. These modifications related to increases in the condensation and crosslinking degree of siloxane and silica species have a strong influence on the relaxation behavior of the NLO chromophores grafted in these hybrid networks. Hybrid organic inorganic nano composites made of metal oxo-polymers (zirconium and neodymium oxo species) linked to siloxane species [(CH3)Si-O3/2] exhibit Nd3+ luminescence properties. At low rare earth concentrations the emission lifetime is mainly governed by some energy transfer processes occurring between the Nd3+ ions. While for higher Nd3+ concentrations the emission lifetime is controlled by Nd-Nd interactions and by an increase of the quenching probability due to the presence of some residual hydroxy groups.

Sanchez, Clement; Lebeau, B.; Viana, Bruno

1994-10-01

178

Dielectric Properties of Polyvinyl Alcohol, Poly(methyl Methacrylate), Polyvinyl Butyral Resin and Polyimide at Low Temperatures  

Microsoft Academic Search

Performance of materials and their compatibility determine the size of the electrical insulation in power equipment. For this reason dielectric properties of electrical insulation materials are needed for low temperature power applications. In this work we report the dielectric properties of four polymers: polyvinyl alcohol (PVA), poly(methyl methacrylate) (PMMA), polyvinyl butyral resin (PVB), and polyimide (PI-Kapton®). The dielectric measurements are

Enis Tuncer; Isidor Sauers; David Randy James; Alvin R. Ellis

2008-01-01

179

DIELECTRIC PROPERTIES OF POLYVINYL ALCOHOL, POLY(METHYL METHACRYLATE), POLYVINYL BUTYRAL RESIN AND POLYIMIDE AT LOW TEMPERATURES  

Microsoft Academic Search

Performance of materials and their compatibility determine the size of the electrical insulation in power equipment. For this reason dielectric properties of electrical insulation materials are needed for low temperature power applications. In this work we report the dielectric properties of four polymers: polyvinyl alcohol (PVA), poly(methyl methacrylate) (PMMA), polyvinyl butyral resin (PVB), and polyimide (PI–Kapton®). The dielectric measurements are

Enis Tuncer; Isidor Sauers; D. Randy James; Alvin R. Ellis

2008-01-01

180

Process for the extrusion of compositions comprising polypropylene, polyvinyl alcohol and a polypropylene-polyvinyl alcohol adhesive  

SciTech Connect

This patent describes a process for extruding a composition comprising polyvinyl alcohol, a polypropylene-polyvinyl alcohol adhesive and a plypropylene prepared with a high activity polymerization catalyst. The improvement consists of utilizing polypropylene having from about 50 to about 5000 ppm by weight of hydrotalcite incorporated therein to substantially eliminate gel formation.

Derrick, W.E.

1989-04-18

181

MECHANICAL PROPERTIES OF BLENDS OF PAMAM DENDRIMERS WITH POLY(VINYL CHLORIDE) AND POLY(VINYL ACETATE)  

EPA Science Inventory

Hybrid blends of poly(amidoamine) PAMAM dendrimers with two linear high polymers, poly(vinyl chloride), PVC, and poly(vinyl acetate), PVAc, are reported. The interaction between the blend components was studied using dynamic mechanical analysis, xenon nuclear magnetic resonacne ...

182

The Effect Of Gender And Knowledge On Students' Impressions Of Accountants In The Post-Enron Era  

Microsoft Academic Search

This study examines college students' impressions of accountants from various sources. It extends previous research on students' impressions of accountants by analyzing impressions after Enron, gender differences in impressions, and the effect of knowledge on impressions and adding news reports as an impression source. Students rated their impressions of accountants when they selected a major on each of 30 characteristics

Steven C. Hunt; Robert C. Intrieri; Anthony Falgiani; Marie T. Papini

2009-01-01

183

Consumer impressions of Tender Select beef.  

PubMed

With the recent development of technology to classify beef for tenderness, it is now possible for packers and retailers to market brands of beef known to be consistently tender. The present experiment was conducted to determine consumer impressions of Tender Select, a model beef brand comprised of cuts from tender U.S. Select carcasses. A telephone survey was conducted in metropolitan Denver, CO, to recruit consumers (n = 1,036) for this study. Consumers who met minimal limits for household income, age, and beef consumption were invited to participate in a beef shopping and usage study in a local supermarket. Point-of-purchase material was developed that described Tender Select as "the only steak guaranteed tender and lean." When shown a copy of the Tender Select concept card, 89% of participating consumers (n = 759) indicated that they would definitely or probably buy that product. Of those consumers that said they would buy the product, 35% indicated that their purchases of Tender Select would be in addition to their current fresh meat purchases. Most consumers (54.1%) indicated that if Tender Select was available at their grocery store, 1 or 2 of their next 10 purchases of beef cuts would be Tender Select. Sixty-five percent of consumers indicated that if a grocery store carried a line of beef cuts guaranteed to be tender, they would buy all of their beef at that store. Both strip loins from 104 U.S. Select beef carcasses, representing a broad range (8.7 to 43.4 kg; CV = 42%) in slice shear force (SSF) at 14 d postmortem, were used to determine the effect of SSF classification on consumer satisfaction and the correlation among trained sensory panel descriptive attribute ratings and in-home consumer ratings of beef longissimus steaks. Both trained sensory panelists and consumers rated low-SSF steaks higher than the high-SSF steaks for all traits (P < 0.001). All consumer traits (like, tenderness, juiciness, flavor like, flavor amount, and overall satisfaction) were more highly correlated with SSF and trained sensory panel tenderness ratings than with sensory panel flavor or juiciness ratings. These data show that tenderness is the primary determinant of satisfaction among consumers of U.S. Select top loin steaks and that a segment of consumers would pay a premium to purchase guaranteed-tender U.S. Select steaks. PMID:11721839

Shackelford, S D; Wheeler, T L; Meade, M K; Reagan, J O; Byrnes, B L; Koohmaraie, M

2001-10-01

184

Synthesis and characterization of novel polysiloxanes. I. Telechelic cyanate esters. II. Hindered alkyl siloxanes  

NASA Astrophysics Data System (ADS)

Two aspects of novel polysiloxane chemistry have been explored in this work: (1) the synthesis and characterization of polysiloxanes functionalized with terminal cyanate ester groups for use as low flammability impact modifiers for commercial phenolic cyanate ester resins (CERs) and (2) the synthesis and characterization of polydiethylsiloxane and polycyclotetramethylenesiloxane. CERs have been proposed as a potentially useful matrix material for commercial aircraft manufacture. However, commercial CERs do not currently have the appropriate fracture toughness for practical applications. Prior studies have shown that siloxanes offer excellent flame suppression and can improve the CERs impact properties. In this work, a series of new siloxanes terminated with cyanate-reactive groups, including bis[1,3-(4--cyanatophenyl)]-1,1,3,3-tetramethyldisiloxane (11), alpha,o-(4-cyanatophenyl) oligodimethylsiloxane (12), and alpha,o-(4-cyanatophenyl) oligo(dimethyl- co-diphenylsiloxane) (13), have been synthesized from corresponding diphenols. The intermediates and products were characterized by 1H NMR, 13C NMR, FTIR, GC-MS, and GPC. To synthesize the diphenols, a new route to synthesize disiloxane terminated with THP protected diphenols (dimer) was established. The synthesized dimer was used to equilibrate with D4 and/or D4'' to make desired siloxane oligomers. The mechanism of the equilibration of the dimer with D4 were studied. The synthesized CER monomers were polymerized by a cyclotrimerization reaction. The cured compound 11 is a brittle solid with Tg of 274°C. The cured 12 (oligodimethyl-siloxane) and 13 (oligodimethylsiloxane- co-diphenylsiloxane) are elastomers with Tg of -110°C and -8°C, respectively. The curing processes and intermediates were studied by dynamic and isothermal differential scanning calorimetry, GPC, IR and 13C NMR. The synthesized CER monomers were used as impact modifiers to blend and co-cure with the commercial CERs, Primaset PT-30. SEM shows that the cured blends of 12 and 13 with PT-30 are multiphase while the cured blend of 11 with PT-30 has no phase separation. In the second part of this work, the synthetic methods for preparing polydiethylsiloxane (PDES) and polycyclotetramethylenesiloxane were explored by both anionic and cationic ring-opening polymerization and by condensation of hydroxyl end-groups in alpha,o-dihydroxy terminated siloxanes. The intermediates and products were characterized by GPC, IR GC-MS and 1H NMR. The process of polycondensation of PDES was followed by GPC and IR.

Fu, Zhidong

185

21 CFR 872.3661 - Optical Impression Systems for CAD/CAM.  

Code of Federal Regulations, 2010 CFR

...Devices § 872.3661 Optical Impression Systems...Identification. An optical impression system for computer assisted design and manufacturing...Guidance Document: Optical Impression Systems for Computer Assisted Design and...

2009-04-01

186

21 CFR 872.3661 - Optical Impression Systems for CAD/CAM.  

Code of Federal Regulations, 2010 CFR

...Devices § 872.3661 Optical Impression Systems...Identification. An optical impression system for computer assisted design and manufacturing...Guidance Document: Optical Impression Systems for Computer Assisted Design and...

2010-04-01

187

[Impressions about responses arising from a sense of unwanted transparency].  

PubMed

The sense of unwanted transparency is the feeling that another person seemingly notices something about us that we would rather conceal. Two experiments were conducted to investigate impressions about responses arising from the sense of unwanted transparency. In Study 1, observers were asked to watch the videotape recorded in Tabata (2009) and judge the participants' responses arising from the sense of unwanted transparency. In Study 2, based on Tabata (2009), both verbal responses and nonverbal responses that were characteristic in arousing the sense of unwanted transparency were manipulated in the videotaped conversation. Participants were asked to watch the videotape and judge the confederate's impressions. The results indicated that unnatural impressions were heightened by nonverbal responses such as longer silences, averting the gaze, and increased self-touching. This suggests that these responses arising from the sense of unwanted transparency may produce a self-fulfilling prophecy. However, seemingly deceptive verbal responses were only related to the dubious impressions of the statements. PMID:21400867

Tabata, Naoya

2011-02-01

188

External and middle ear trauma resulting from ear impressions.  

PubMed

When taking an impression of the external ear canal and ear, the audiologist is engaged in an invasive procedure whereby a foreign body is first placed into the ear canal and then removed. There is always an element of risk for significant medical problems when a clinician is performing an invasive procedure. Although some minor patient discomfort and, at times, some slight trauma to the ear canal occur when taking ear impressions, the incidence of significant trauma to the external or middle ear appears to be low. The purpose of this report is to provide some illustrative cases of significant external and middle ear trauma as a result of taking impressions of the external ear. Audiologists are advised to develop and implement an appropriate risk management program for taking ear impressions to reduce the potential risks associated with this procedure to their patients and to their practices. PMID:10976496

Wynne, M K; Kahn, J M; Abel, D J; Allen, R L

189

Functional impressions for complete denture fabrication. A modified jump technique.  

PubMed

Tissue conditioners are used with great success in dentistry as functional impression materials for rebasing removable prostheses. In the rebase procedure, a functional impression is made in an existing denture to create a master cast. The orientation of the occlusal surface to the underlying tissue surface is captured with a reline jig or denture flask and transferred to the new denture base in what is called a "jump" in laboratory jargon. Functional impression methods are not commonly considered, however, for the fabrication of new dentures despite their popularity and ease of use. This article describes a modified jump technique for remaking complete dentures. The method uses functional impressions in existing maxillary and mandibular dentures to create master casts and to act as stabilized carriers for jaw relation records. More precise esthetic and phonetic assessments of the existing prostheses are accommodated, and prescriptive changes may be referenced to the current tooth arrangement. PMID:20446488

Haney, Stephan J; Nicoll, Roxanna; Mansueto, Michael

2010-04-01

190

Use of casting tape for support of an extraoral impression.  

PubMed

This article describes a technique for using casting tape to support irreversible hydrocolloid material when making extraoral impressions to increase patient comfort, save time, and produce less tissue distortion. PMID:14668762

Siadat, Hakimeh; Mirfazaelian, Ali

2003-12-01

191

Synthetic casting tape as a facial impression tray material.  

PubMed

A procedure is described that uses thermoplastic synthetic casting tape for fabrication of facial impression trays. Once used, these trays can be disinfected without degradation of the tray material, which allows for storage and later use. PMID:8537924

Saunders, T R; Hansen, N A

1995-08-01

192

Irradiation of polyvinyl alcohol and polyvinyl pyrrolidone blended hydrogel for wound dressing  

NASA Astrophysics Data System (ADS)

Polyvinyl alcohol and polyvinyl pyrrolidone (PVA-PVP) blended hydrogel for wound dressing has been prepared by using gamma rays irradiation technique. The gel fraction, mechanical properties, the water content and water absorption performance of the hydrogels were measured. It was found that the gel fraction increases with increasing irradiation dose but never reaches 100% of gel. The PVA/PVP blended hydrogel has a water content in the range between 60% and 80% and water absorption between 40% and 250%. The water vapor transmission rate value (WVTR) of the PVA/PVP blended hydrogel varies between 50 and 200g/m2/h. The hydrogel could be considered as good barrier against microbes. According to in vitro assessment it was found that the PVA/PVP blended hydrogel was very useful material that can meet the efficacy requirement and its healing rate was comparable with sterilized gauze and sofratulle.

Razzak, M. T.; Darwis, D.; Zainuddin,; Sukirno,

2001-07-01

193

Fluorinated/siloxane copolymer blends for fouling release: chemical characterisation and biological evaluation with algae and barnacles.  

PubMed

Fouling-release coatings were prepared from blends of a fluorinated/siloxane copolymer with a poly(dimethyl siloxane) (PDMS) matrix in order to couple the low modulus character of PDMS with the low surface tension typical for fluorinated polymers. The content of the surface-active copolymer was varied in the blend over a broad range (0.15-10 wt % with respect to PDMS). X-ray photoelectron spectroscopy depth profiling analyses were performed on the coatings to establish the distribution of specific chemical constituents throughout the coatings, and proved enrichment in fluorine of the outermost layers of the coating surface. Addition of the fluorinated/siloxane copolymer to the PDMS matrix resulted in a concentration-dependent decrease in settlement of barnacle, Balanus amphitrite, cyprids. The release of young plants of Ulva, a soft fouling species, and young barnacles showed that adhesion strength on the fluorinated/siloxane copolymer was significantly lower than the siloxane control. However, differences in adhesion strength were not directly correlated with the concentration of copolymer in the blends. PMID:19373571

Marabotti, Ilaria; Morelli, Andrea; Orsini, Lorenzo M; Martinelli, Elisa; Galli, Giancarlo; Chiellini, Emo; Lien, Einar M; Pettitt, Michala E; Callow, Maureen E; Callow, James A; Conlan, Sheelagh L; Mutton, Robert J; Clare, Anthony S; Kocijan, Aleksandra; Donik, Crtomir; Jenko, Monika

2009-01-01

194

Polyvinyl alcohol membranes as alkaline battery separators  

SciTech Connect

Polyvinyl alcohol (PVA) cross-linked with aldehyde reagents yields membranes that demonstrate properties that make them suitable for use as alkaline battery separators. Film properties can be controlled by the choice of cross-linker, cross-link density and the method of cross-linking. Three methods of cross-linking and their effects on film properties are discussed. Film properties can also be modified by using a copolymer of vinyl alcohol and acrylic acid as the base for the separator and cross-linking it similarly to the PVA. Fillers can be incorporated into the films to further modify film properties. Results of separator screening tests and cell tests for several variations of PBA films are discussed.

Sheibley, D.W.; Gonzalez-Sanabria, O.; Manzo, M.

1982-01-01

195

Fabrication of polyvinyl alcohol coated polystyrene shells  

SciTech Connect

Glass shells have been used traditionally as the deuterium--tritium fuel container for direct-drive laser fusion experiments because of their convenience and availability, but lower-Z fuel containers have superior implosion characteristics and diagnostic possibilities. Unfortunately, polymers such as polystyrene (PS) that produce shells easily have very high permeabilities so require cryogenics to retain fuel, and impermeable polymers such as polyvinyl alcohol (PVA) are difficult to make into high-quality shells. We have developed improved methods of making PS shells with diameters from 0.2 to 0.7 mm and coating them with a 3-..mu..m layer of PVA to obtain the advantages of both. Both the PS shells and the PVA coating are made in drop towers using gas-stripped nozzles. Details of the procedures and product quality are discussed.

Burnham, A.K.; Grens, J.Z.; Lilley, E.M.

1987-11-01

196

[Survey of plasticizers in polyvinyl chloride toys].  

PubMed

Plasticizers in 101 samples of polyvinyl chloride (PVC) toys on the Japanese market were surveyed. No phthalates were detected in designated toys, though bis(2-ethylhexyl)phthalate, diisononyl phthalate, diisobutyl phthalate, dibutyl phthalate, diisodecyl phthalate and benzyl butyl phthalate were detected in more than half of other toys. 2,2,4-Tributyl-1,3-pentanediol diisobutylate, o-acetyl tributyl citrate, adipates and diacetyl lauroyl glycerol, which are alternative plasticizers to phthalates, were detected. The results of structural analysis confirmed the presence of di(2-ethylhexyl)terephthalate, tributyl citrate, diisononyl 1,2-cyclohexanedicarboxylate and neopentyl glycol esters; these have not previonsly been reported in Japan. There appears to be a shift in plasticizers used for designated toys from phthalates to new plasticizers, and the number of different plasticizers is increasing. PMID:22450665

Abe, Yutaka; Yamaguchi, Miku; Mutsuga, Motoh; Hirahara, Yoshichika; Kawamura, Yoko

2012-01-01

197

Effect of impression coping and implant angulation on the accuracy of implant impressions: an in vitro study  

PubMed Central

PURPOSE The purpose of this study was to compare the accuracy of the implant master cast according to the type (pick-up, transfer) and the length (long, short) of the impression copings. MATERIALS AND METHODS The metal master cast was fabricated with three internal connection type implant analogs (Osstem GS III analog), embedded parallel and with 10° of mesial angulation to the center analog. Four types of impression coping were prepared with different combinations of types (transfer, pick-up) and lengths (long, short) of the coping. The impressions were made using vinyl polysiloxane (one step, heavy + light body) with an individual tray, and 10 impressions were made for each group. Eventually, 40 experimental casts were produced. Then, the difference in the distance between the master cast and the experimental cast were measured, and the error rate was determined. The analysis of variance was performed using the SPSS (v 12.0) program (? = .05), and the statistical significance was set at P < .05. RESULTS The ANOVA showed that the pick-up type impression coping exhibited a significantly lower error rate than the transfer type. However, no significant difference was observed with respect to the length of the impression coping. Additionally, no significant difference was observed between the parallel and mesial angulated groups. CONCLUSION Within the limitations of this study, the pick-up type impression coping exhibited a more accurate implant master cast than the transfer type in parallel group. The accuracy of the implant master cast did not differ for different lengths of impression coping of at least 11 mm. Additionally, the accuracy of the implant cast was not different for the parallel and 10° mesial angulated groups.

Jo, Si-Hoon; Kim, Kyoung-Il; Seo, Jae-Min; Song, Kwang-Yeob; Park, Ju-Mi

2010-01-01

198

Studies on surface wettability of poly(dimethyl) siloxane (PDMS) and glass under oxygen-plasma treatment and correlation with bond strength  

Microsoft Academic Search

An issue in microfabrication of the fluidic channels in glass\\/poly (dimethyl siloxane) (PDMS) is the absence of a well-defined study of the bonding strength between the surfaces making up these channels. Although most of the research papers mention the use of oxygen plasma for developing chemical (siloxane) bonds between the participating surfaces, yet they only define a certain set of

Shantanu Bhattacharya; Arindom Datta; Jordan M. Berg; Shubhra Gangopadhyay

2005-01-01

199

[Distortion of working models using different silicone impression techniques].  

PubMed

The influences of differing strains levels of impression materials in compression and impression techniques on the distortion of working models were examined. The working models, which differed in the size of cervical spillway (2mm and 9mm) and the impression techniques applied (the two-phase technique and the wash technique), were produced by using putty-type impression materials with three different strain levels (Reprosil, Express and Exaflex) following the metal master model of mandibular denture in an abutment form. Distortion of the working models was then measured by a three-dimensional measuring system. The results were as follows. 1) The models produced through the impression technique using hard impression materials with low strain levels displayed decreases both in the degree of inclination to the X axis of the abutment tooth variations distance between the left and right abutment teeth. This procedure was found to yield a model which was proximate to the master model. 2) The impression technique incorporating a small cervical spillway resulted in decreases in variations in the distance between the right and left abutment teeth and the diameter of the molar part of the abutment tooth, and the horizontal distortion of the alveolar ridge; the model thus produced was found to be proximate to the master model. 3) Application of the two-phase technique reduced variations in height of the abutment tooth, and the use of the wash technique led to decreased variations in the distance between the right and left abutment teeth and diameter of the molar cervix of the abutment tooth. 4) Differences in strain levels of putty-type impression materials, the size of cervical spillway and the impression technique used did not influence deviation of the model toward the Y axis (vertical direction). 5) The models with least distortion of the abutment tooth were obtained by the two-phase technique using hard impression materials with lower strain levels or by the wash technique using soft materials with higher strain levels. PMID:2489335

Yomaru, H; Ohtake, H; Yokozuka, S

1989-10-01

200

Monitoring Vinyl Chloride Around Polyvinyl Chloride Fabrication Plants.  

National Technical Information Service (NTIS)

A program to measure vinyl chloride emissions from polyvinyl chloride fabrication plants was carried out. Four charcoal collectors were stationed around each of five PVC fabrication plants. 24-hour samples were collected daily for 14 days around each plan...

1975-01-01

201

21 CFR 175.270 - Poly(vinyl fluoride) resins.  

Code of Federal Regulations, 2010 CFR

...fluoride) resins consist of basic resins produced by the polymerization of...The poly(vinyl fluoride) basic resins have an intrinsic viscosity...technical grade. (2) Solution. Powdered resin and solvent are heated at...

2010-01-01

202

Compatibility of Polyvinyl Chloride Filter Bags with Chloroform Vapors.  

National Technical Information Service (NTIS)

A determination is made on the compatibility of polyvinyl chloride (PVC) filter bags when exposed to chloroform vapors resulting from offgassing of contaminated adsorbent filters. The objectives of this investigation were to estimate the concentrations of...

C. J. Karwacki

1997-01-01

203

Formalized Poly(Vinyl Alcohol) Membranes for Reverse Osmosis.  

National Technical Information Service (NTIS)

The permeation properties of formalized poly(vinyl alcohol) membranes are described. The interest of this work is centered on the properties relevant to desalination by reverse osmosis. These membranes, when properly prepared, showed reasonably high water...

A. V. Tobolsky C. T. Chen M. C. Chen Y. J. Chang

1972-01-01

204

Calorimetric characterization of membrane materials based on polyvinyl alcohol  

Microsoft Academic Search

There is ample scope for modification of polyvinyl alcohol (PVA) to derive diverse range of properties because of the presence\\u000a of hydroxyl group in its chain. In the present work, PVA has been modified to carboxymethylated polyvinyl alcohol (CPVA) —\\u000a a carboxy-functionalized membrane material. Generally the cohesive energy density has incremental influence on the melting\\u000a point and mechanical strength of

G. S. Mukherjee

2009-01-01

205

Synthesis and characterization of imide ring and siloxane-containing cycloaliphatic epoxy resins  

Microsoft Academic Search

A novel imide ring and siloxane-containing cycloaliphatic epoxy compound 1,3-bis[3-(4,5-epoxy-1,2,3,6-tetrahydrophthalimido)propyl]tetramethyldisiloxane (BISE) was synthesized from 1,3-bis(3-aminopropyl)tetramethyldisiloxane and tetrahydrophthalic anhydride by a two-step procedure, which was then thermally cured with alicyclic anhydrides hexahydro-4-methylphthalic anhydride (HMPA) and hexahydrophthalic anhydride (HHPA), respectively. As comparison, a commercial available cycloaliphatic epoxy 3,4-epoxycyclohexylmethyl-3?,4?-epoxycyclohexane carboxylate (ERL-4221) cured with the same curing agents was also investigated. The experimental results

Zhiqiang Tao; Shiyong Yang; Jiansheng Chen; Lin Fan

2007-01-01

206

Preparation and properties of halogen-free flame retardant epoxy resins with phosphorus-containing siloxanes  

Microsoft Academic Search

Novel epoxy resin modifiers, DOPO–TMDS and DOPO–DMDP were synthesized by addition reaction of divinylsiloxane with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide\\u000a (DOPO). Halogen-free flame retardant epoxy resins were obtained through modification of o-cresol novolac epoxy resin cured by phenol novolac resin using DOPO–TMDS and DOPO–DMDP which were characterized by 1H NMR, 13C NMR, 31P NMR and FT-IR measurements. Effects of the phosphorus-containing siloxanes on thermal

Jiapei Ding; Zhiqiang Tao; Xiaobiao Zuo; Lin Fan; Shiyong Yang

2009-01-01

207

Semipermeable thin-film membranes comprising siloxane, alkoxysilyl and aryloxysilyl oligomers and copolymers  

DOEpatents

Novel semiperimeable membranes and thin film composite (TFC) gas separation membranes useful in the separation of oxygen, nitrogen, hydrogen, water vapor, methane, carbon dioxide, hydrogen sulfide, lower hydrocarbons, and other gases are disclosed. The novel semipermeable membranes comprise the polycondensation reaction product of two complementary polyfunctional compounds, each having at least two functional groups that are mutually reactive in a condensation polymerization reaction, and at least one of which is selected from siloxanes, alkoxsilyls and aryloxysilyls. The TFC membrane comprises a microporous polymeric support, the surface of which has the novel semipermeable film formed thereon, preferably by interfacial polymerization.

Babcock, Walter C. (Bend, OR); Friesen, Dwayne T. (Bend, OR)

1988-01-01

208

The Use of Impression Management Tactics in Structured Interviews: A Function of Question Type?  

Microsoft Academic Search

This study investigated impression management tactic use during structured interviews containing both experience-based and situational questions. Specifically, the authors examined whether applicants' use of impression management tactics depended on question type. Results from 119 structured interviews indicated that almost all of the applicants used some form of impression management. Significantly more assertive than defensive impression management tactics were used, and

Aleksander P. J. Ellis; Bradley J. West; Ann Marie Ryan; Richard P. DeShon

2002-01-01

209

The use of impression management tactics in structured interviews: A function of question type?  

Microsoft Academic Search

This study investigated impression management tactic use during structured interviews containing both experience-based and situational questions. Specifically, the authors examined whether applicants' use of impression management tactics depended on question type. Results from 119 structured interviews indicated that almost all of the applicants used some form of impression management. Significantly more assertive than defensive impression management tactics were used, and

Aleksander P. J. Ellis; Bradley J. West; Ann Marie Ryan; Richard P. DeShon

2002-01-01

210

Impression Management Versus Intrapsychic Explanations in Social Psychology: A Useful Dichotomy?  

Microsoft Academic Search

Impression management refers to the behavioral strategies that people use to create desired social images or identities. This article focuses on the current status of impression management explanations in social psychology. We argue that the common practice of referring to impression management theory is misleading. Many potential theories of impression management exist, each based on distinct assumptions. We also review

Philip E. Tetlock; Antony S. Manstead

1985-01-01

211

Effect of Time on Gypsum-Impression Material Compatibility  

NASA Astrophysics Data System (ADS)

The purpose of this study was to evaluate the compatibility of dental gypsum with three recently introduced irreversible hydrocolloid (alginate) alternatives. The test materials were Alginot® (Kerr™), Position Penta Quick® (3M ESPE™) and Silgimix ® (Sultan Dental™). The irreversible hydrocolloid impression material, Jeltrate Plus antimicrobial® (Dentsply Caulk™) served as the control. Materials and Methods: Testing of materials was conducted in accordance with ANSI/ADA Specification No. 18 for Alginate Impression Materials. Statistical Analysis: The 3-Way ANOVA test was used to analyze measurements between different time points at a significance level of (p < 0.05). Outcome: It was found that there was greater compatibility between gypsum and the alternative materials over time than the traditional irreversible hydrocolloid material that was tested. A statistically significant amount of surface change/incompatibility was found over time with the combination of the dental gypsum products and the control impression material (Jeltrate Plus antimicrobial®).

Won, John Boram

212

A systematic review of impression technique for conventional complete denture.  

PubMed

The importance of an in depth review of impression making for complete dentures lies in the assessment of the historical value of all the factors related to physical, biologic and behavioral areas and the time in which they were discussed and taught as well. This review documents the historical development of knowledge associated with scientific advancement from 1845 to the present year, i.e. 2009 related to impression procedures in conventional complete denture prosthesis. Search for articles was done through electronic media the Pubmed. PMID:21629453

Rao, Shubha; Chowdhary, R; Mahoorkar, S

2010-12-17

213

[Impression management and self-presentation in occupational life].  

PubMed

Impression management serves self-preservation as part of self-experience. It is adapted to a given situation as an expression of understanding of the role it plays in striving for success. Impression management and self-presentation mutually influence each other throughout life. Clichés in the traditional self-presentation of men and woman in their gender-specific domain in occupation belong to the past. In employment, contentment as much as discontent are of prime importance for success or failure in the workplace. As role models attract mainly juveniles, they should be held up to critical scrutiny. PMID:23926706

Stresemann, E

2013-06-01

214

Preparation and properties of polyvinyl alcohol microspheres  

SciTech Connect

Polyvinyl alcohol (PVA) microspheres, having a size range of approx.150- to 250-..mu..m diameter with 1- to 5-..mu..m wall thickness, have been fabricated using a solution droplet technique. The spheres were developed for possible use on the Lawrence Livermore National Laboratory (LLNL) Inertial Confinement Fusion (ICF) Program. PVA, a polymer chosen based on earlier survey work carried out at KMS Fusion, Inc., has good strength, low hydrogen permeability, is optically transparent, and water soluble. The latter property makes it safe and easy to use in our droplet generator system. A unique dual-orifice droplet generator was used to prepare the spheres. The droplet generator operating conditions and the column processing parameters were chosen using results from our 1-D model calculations as a guide. The polymer microsphere model is an extension of the model we developed to support the glass sphere production. After preparation, the spheres were physically characterized for surface quality, sphericity, wall thickness (and uniformity), and size. We also determined the buckling pressure for both uncoated and CH-coated spheres. Radiation stability to beta decay (from tritium) was evaluated by exposing the spheres to a 7-keV electron beam. The results from these and other physical property measurements are presented in this report.

Campbell, J.H.; Grens, J.Z.; Poco, J.F.; Ives, B.H.

1986-06-01

215

Heat resistance poly(vinyl alcohol) hydrogel  

NASA Astrophysics Data System (ADS)

Six methods were used to evaluate the heat resistance of poly(vinyl alchol) (PVA) hydrogel prepared by a combination of electron beam irradiation and acetalization of PVA. The physical properties of the hydrogel depended on the degree of acetalization which was affected by content of water in PVA sheet of acetalization in formaldehyde solution at 60°C. It was found that the optimum water content was 20-30%. The acetalized PVA sheet gave maximum tensile strength in electron beams irradiatio nat 100 kGy. The tensile strength of the hydrogel film increased to 20 MPa from 14 MPa by the irradiation. Heat resistance of the hydrogel was evaluated by measuring the mechanical properties after sterilization in a steam autoclave at 121°C for 90 min. The tensile strength decreased to 10 MPa whereas the elongation at break increased to 300%. The tackiness of the hydrogel was improved by radiation grafting of acrylic acid. Wholesomeness of the hydrogel as a wound dressing was evaluated by attaching to a burn or wound of the back skin of marmots. Advantages of the hydrogel over a gauze dressing were homogeneous adhesion to the affected parts, easy removal without damage to renewed skin and slightly faster rate of reconstruction of the injured skin.

Yoshii, F.; Makuuchi, K.; Darwis, D.; Iriawan, T.; Razzak, M. T.; Rosiak, Janusz M.

1995-08-01

216

Study of zwitterionic sulfopropylbetaine containing reactive siloxanes for application in antibacterial materials.  

PubMed

Antibacterial agents receive a great deal of attention around the world due to the interesting academic problems of how to combat bacteria and of the beneficial health, social and economic effects of successful agents. Scientists are actively developing new antibacterial agents for biomaterial applications. This paper reports the novel antibacterial agent siloxane sulfopropylbetaine (SSPB), which contains reactive alkoxysilane groups. The structure and properties of SSPB were systematically investigated, with the results showing that SSPB contains both quaternary ammonium compounds and reactive siloxane groups. SSPB has good antibacterial activity against both Escherichia coli (E. coli, 8099) and Staphylococcus aureus (S. aureus, ATCC 6538). The minimal inhibition concentration is 70 ?mol/ml SSPB against both E. coli and S. aureus. In addition, the SSPB antibacterial agent can be used in both weak acid and weak alkaline environments, functioning within the wide pH range of 4.0-9.0. The SSPB-modified glass surface killed 99.96% of both S. aureus and E. coli organisms within 24 h. No significant decrease was observed in this antibacterial activity after 20 washes. Moreover, SSPB does not induce a skin reaction and is nontoxic to animals. Thus, SSPB is an ideal candidate for future applications as a safe, environmentally friendly antibacterial agent. PMID:21450443

Chen, Shiguo; Chen, Shaojun; Jiang, Song; Mo, Yangmiao; Luo, Junxuan; Tang, Jiaoning; Ge, Zaochuan

2011-03-29

217

Siloxane-poly(lactic acid)-vaterite composites with 3D cotton-like structure.  

PubMed

Trace amounts of ionic calcium and silicon species have been reported to stimulate the proliferation, differentiation, and mineralization of bone-forming cells. Composite materials comprising siloxane-doped calcium carbonate (vaterite) particles and poly(L-lactic acid) have been developed [siloxane-poly(lactic acid)-vaterite hybrid-composite, SiPVH] so far; they were designed such that calcium and silicate ions are gradually released from SiPVH and they show the chronic effects of ions on cellular activities. In the present work, SiPVH with a 3D cotton-like structure was prepared by electrospinning to obtain the major advantages of excellent bioactivity and ease of handling for bone filling surgery. The diameter of the fibrous skeletons that form structure of the cotton-like SiPVH was controlled to ~10 ?m to achieve cellular migration into the spaces between fibers. The resulting cotton-like SiPVH showed good flexibility. The fiber surface was coated rapidly with numerous particles of several hundred nanometers in size by alternate soaking in CaCl(2) and Na(2)HPO(4). The treated cotton-like material, which released calcium and silicate ions gradually, showed good cellular migration behavior into the 3D structure in cell culture tests using murine osteoblast-like MC3T3-E1 cells. PMID:22415363

Kasuga, Toshihiro; Obata, Akiko; Maeda, Hirotaka; Ota, Yoshio; Yao, Xianfeng; Oribe, Kazuya

2012-03-14

218

Triblock siloxane copolymer surfactant: template for spherical mesoporous silica with a hexagonal pore ordering.  

PubMed

Ordered mesoporous silica materials with a spherical morphology have been prepared for the first time through the cooperative templating mechanism (CTM) by using a silicone triblock copolymer as template. The behavior of the pure siloxane copolymer amphiphile in water was first investigated. A direct micellar phase (L(1)) and a hexagonal (H(1)) liquid crystal were found. The determination of the structural parameters by SAXS measurements leads us to conclude that in the hexagonal liquid crystal phase a part of the ethylene oxide group is not hydrated as observed for the micelles. Mesoporous materials were then synthesized from the cooperative templating mechanism. The recovered materials were characterized by SAXS measurements, nitrogen adsorption-desorption analysis, and transmission and scanning electron microscopy. The results clearly evidence that one can control the morphology and the nanostructuring of the resulting material by modifying the synthesis parameters. Actually, highly ordered mesoporous materials with a spherical morphology have been obtained with a siloxane copolymer/tetramethoxysilane molar ratio of 0.10 after hydrothermal treatment at 100 °C. Our study also supports the fact that the interactions between micelles and the hydrolyzed precursor are one of the key parameters governing the formation of ordered mesostructures through the cooperative templating mechanism. Indeed, we have demonstrated that when the interactions between micelles are important, only wormhole-like structures are recovered. PMID:23305163

Stébé, M J; Emo, M; Forny-Le Follotec, A; Metlas-Komunjer, L; Pezron, I; Blin, J L

2013-01-22

219

Solvent effects on silica domain growth in silica/siloxane composite materials  

SciTech Connect

The effect of solvent addition on the phase separation, mechanical Properties and thermal stability of silica/siloxane composite materials prepared by in situ reinforcement was examined. The addition of a solvent enhances the miscibility of the reinforcement precursor, a partial hydrolyzate of tetraethoxysilane (TEOS-PH), with the polydimethylsiloxane (PDMS) polymer. As a result, the phase separation at the micron level, termed the large-scale structure, diminished in size. This decrease in particle size resulting from the addition of moderate amounts of solvent was accompanied by an improvement in the mechanical properties. However, solvent addition in the excess of 50 weight percent led to a decrease in mechanical properties even though the large-scale structure continued to diminish in size. Small Angle X-Ray Scattering (SAXS) was used to examine the Angstrom level or small-scale structure. This small-scale structure was only affected by the presence of solvent, not the amount. The silica/siloxane composite materials showed the same thermal transition temperatures as the original PDMS material.

Ulibarri, T.A.; Bates, S.E.; Black, E.P.; Schaefer, D.W. [Sandia National Labs., Albuquerque, NM (United States); Beaucage, W.G. [Univ. of Cincinnati, Cincinnati, OH (United States); Lee, M.K.; Moore, P.A.; Burns, G.T. [Dow Corning Corp., Midland, MI (United States)

1995-07-01

220

Computer simulation of cyclic siloxane-based liquid crystals: Molecular dynamics and x ray scattering  

NASA Astrophysics Data System (ADS)

The molecular dynamics technique is employed in the present study to investigate molecular models of a liquid crystal (LC) based on cyclic penta(methylsiloxane) with combinations of cholesteryl4'- allyloxybenzoate and biphenyl- 4'allyloxybenzoate mesogens, which is of technological importance because of attributes related to light processing media. The packing and structure exhibited by these commercially available cholesteric LC's show unusually well-defined interlayer order giving rise to high order x-ray reflections. The purpose of this investigation was to: (1) investigate the conformational flexibility of the molecular arrangements and organization of this cyclic siloxane-based LC at room temperature, providing insight into the relative stability of the various models proposed; and (2) serve as an instructional reference describing the basic theory and use of molecular mechanics and dynamics for the study of large molecular systems. Results from the molecular dynamics calculations indicate the degree of conformational flexibility among the pendant mesogens of this molecular system and its effects on interdigitation. In particular, the isolated disk model exhibits the most flexibility and greatest stability as indicated by mean dihedral angles and range for certain key torsions. The dynamics simulation of the cylinder pairs suggests a large conformational flexibility of the siloxane rings. Also, movements of the interdigitated mesogens were much higher for a fixed ring system than for the case where the ring atoms were free to move. X-ray scattering pattern calculations for the structures generated during the dynamics run demonstrate higher order than for the initial models.

Socci, E. P.; Farmer, B. L.; Pachter, R.; Adams, W. W.; Bunning, T. J.

1992-01-01

221

Synthesis and Characterization of Thiol-Ene Functionalized Siloxanes and Evaluation of their Crosslinked Network Properties  

PubMed Central

Three types of linear thiol-functionalized siloxane oligomers and three types of ene-functionalized oligomers were synthesized and subsequently photopolymerized. Within each type of thiol-functionalized oligomer, the ratio of mercaptan repeat units to non-reactive phenyl repeat units was varied to manipulate both the crosslink density and the degree of secondary interactions through pi-pi stacking. Similarly, the repeat units of the three ene-functionalized oligomers are composed of allyl-functional monomers, benzene-functional monomers, and octyl-functional monomers in varying ratios of benzene:octyl but with a constant fraction of allyl moieties. The structural composition of the siloxane oligomers plays a pivotal role in the observed material properties of networks formed through thiol-ene photopolymerization. Networks with a high concentration of thiol functionalities exhibit higher rubbery moduli, ultimate strengths, and Young’s moduli than networks with lower thiol concentrations. Moreover, the concentration of functionalities capable of participating in secondary interactions via hydrogen bonding or pi-pi stacking directly impacts the network glass transition temperature and elasticity. The combination of low crosslink density and high secondary interactions produces networks with the greatest toughness. Finally, the fraction of octyl repeats correlates with the hydrophobic nature of the network.

Cole, Megan A.; Bowman, Christopher N.

2012-01-01

222

75 FR 55552 - Polyvinyl Alcohol From Taiwan: Preliminary Determination of Sales at Less Than Fair Value and...  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Preliminary Determination...preliminarily determines that sales of polyvinyl alcohol (PVA) from Taiwan are being...Dumping Duty Investigation: Polyvinyl Alcohol From Taiwan, 69 FR...

2010-09-13

223

78 FR 37794 - Polyvinyl Alcohol from Taiwan: Final Results of Antidumping Duty Administrative Review; 2010-2012  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-841] Polyvinyl Alcohol from Taiwan: Final Results...the antidumping duty order on polyvinyl alcohol (PVA) from Taiwan. For these...1\\ See Polyvinyl Alcohol From Taiwan: Preliminary...

2013-06-24

224

Evaluation of Aluminum Foil-Interlayed High-Modulus K13CU Pitch Fiber-Siloxane-Modified Resin Composite Panels.  

National Technical Information Service (NTIS)

A contractor is currently fabricating flat panels of high-modulus fiber K13CU/siloxane-modified polycyanurate matrix resin composites. Mechanical testing at a commercial lab showed that the interlaminar shear strengths and the flat-wise tensile properties...

R. J. Zaldivar R. Casteneda

2003-01-01

225

Sense impression as an encoding dimension of words  

Microsoft Academic Search

Conducted 5 experiments with 96 undergraduates each measuring release from proactive inhibitive in the L. R. Peterson and M. J. Peterson paradigm as a function of changes in various subdimensions of the broad dimension of sense impression. Certain aspects of this general dimension seemed to serve as quite effective encoding attributes, while others were less potent. An extradimensional shift (e.g.,

Delos D. Wickens; Donald B. Reutener; F. Thomas Eggemeier

1972-01-01

226

First Impressions: Gait Cues Drive Reliable Trait Judgements  

ERIC Educational Resources Information Center

|Personality trait attribution can underpin important social decisions and yet requires little effort; even a brief exposure to a photograph can generate lasting impressions. Body movement is a channel readily available to observers and allows judgements to be made when facial and body appearances are less visible; e.g., from great distances.…

Thoresen, John C.; Vuong, Quoc C.; Atkinson, Anthony P.

2012-01-01

227

Impressions of a Middle Grades STEM Integration Program  

ERIC Educational Resources Information Center

This article describes the experiences of one Minnesota middle school that implemented a year-long integrated STEM program with the cooperation of graduate student fellows from a local university. The authors, two of whom were among the graduate students involved in the project, describe their impressions of the program, share some lessons they…

Stohlmann, Micah; Moore, Tamara J.; McClelland, J.; Roehrig, Gillian H.

2011-01-01

228

The Effect of Deviant Group Membership upon Impressions of Personality  

Microsoft Academic Search

Personality impressions of a videotaped stimulus person were compared when he was introduced as a member of a homosexual group to when he was not. It was predicted that no differences would be found in overall attraction, but that the homosexual condition would elicit ratings consistent with a male homosexual stereotype. Results were consistent with the hypothesis; in the homosexual

Theodore A. Weissbach; Gary Zagon

1975-01-01

229

DRESSING TO IMPRESS: BELIEFS AND ATTITUDES REGARDING WORKPLACE ATTIRE  

Microsoft Academic Search

The purpose of this study was to examine individual differences in beliefs and attitudes regarding workplace attire including: the value placed on clothing, the impact of attire on workplace outcomes (e.g., promotions, raises), the effort and planning involved in dressing appropriately for work, how their clothing made them feel, and whether they used their attire to manage the impression of

Joy V. Peluchette; Katherine Karl; Kathleen Rust

2006-01-01

230

Beneficial Impression Management: Strategically Controlling Information to Help Friends  

Microsoft Academic Search

It was hypothesized that people will strategically regulate information about the identities of friends to help them create desired impressions on audiences. Experiment 1 demonstrated that participants described a friend consistently with the qualities preferred by an attractive, opposite-sex individual but inconsistently with the qualities preferred by an unattractive, opposite-sex individual. Experiment 2 showed that a friend who had a

Barry R. Schlenker; Thomas W. Britt

1999-01-01

231

Privacy in instant messaging: an impression management model  

Microsoft Academic Search

Instant messaging (IM) has evolved into an important tool for collaborative work. It supports informal near-synchronous communication and fosters awareness of the online presence of one's communication partners. Like all awareness systems, IM runs into concerns regarding privacy. Drawing upon prior literature and exploratory interviews, we postulate a model that posits impression management as an underlying cause for privacy desires

Alfred Kobsa; Sameer Patil; Bertolt Meyer

2010-01-01

232

Third-Person Perception as an Impression Management Tactic  

Microsoft Academic Search

The current research aims at broadening the motivational explanations for the third-person perception (TPP) by documenting the role of impression management motives in this perception. In two experiments that were devised to explore this possibility, participants were asked to report in public or in private on their perceptions of how various advertisements affected them and others. In addition, their level

Nurit Tal-Or; Dorit Drukman

2010-01-01

233

The Influence of Ink on the Quality of Fingerprint Impressions.  

National Technical Information Service (NTIS)

Tests were conducted on several types of ink to determine their influence on the quality of fingerprint impressions which they could produce. The thickness and uniformity of the film used to ink the fingers were found to be the most significant factor in ...

R. T. Moore

1974-01-01

234

Impression management and Self-Deception in traffic behaviour inventories  

Microsoft Academic Search

Traffic behaviour questionnaires as self-reports of behaviour are easily biased by Socially Desirable Responding (SDR), especially in investigating ‘normal’ behaviour rather than maximum performance. Despite this fact no instruments are available for measuring traffic related SDR. The present study introduces a new inventory, the Driver Social Desirability Scale (DSDS), for measuring driver impression management (DIM) and Driver Self-Deception (DSD). The

Timo Lajunen; Angela Corry; Heikki Summala; Laurence Hartley

1997-01-01

235

Temporary Employment and Perceived Employability: Mediation by Impression Management  

ERIC Educational Resources Information Center

|Perceived employability (PE) has been advanced as the upcoming resource for career development, particularly for temporary workers. The question is how temporary workers become employable. Our hypothesis is that temporary workers more than permanent workers use impression management to become employable, both on the internal and the external…

De Cuyper, Nele; De Witte, Hans

2010-01-01

236

First Impressions: Gait Cues Drive Reliable Trait Judgements  

ERIC Educational Resources Information Center

Personality trait attribution can underpin important social decisions and yet requires little effort; even a brief exposure to a photograph can generate lasting impressions. Body movement is a channel readily available to observers and allows judgements to be made when facial and body appearances are less visible; e.g., from great distances.…

Thoresen, John C.; Vuong, Quoc C.; Atkinson, Anthony P.

2012-01-01

237

Temporary Employment and Perceived Employability: Mediation by Impression Management  

ERIC Educational Resources Information Center

Perceived employability (PE) has been advanced as the upcoming resource for career development, particularly for temporary workers. The question is how temporary workers become employable. Our hypothesis is that temporary workers more than permanent workers use impression management to become employable, both on the internal and the external labor…

De Cuyper, Nele; De Witte, Hans

2010-01-01

238

Cross-Cultural Impression Management: A Cultural Knowledge Audit Model  

ERIC Educational Resources Information Center

Purpose: Many people moving into a new culture for work or study do so without prior cross-cultural training, yet successful cultural adaptation has important ramifications. The purpose of this paper is to focus on cross-cultural impression management as an element of cultural adaptation. Does cultural adaptation begin by paying strong attention…

Spong, Abigail; Kamau, Caroline

2012-01-01

239

Initial Impressions: Reflections of Pre-Service Educators  

ERIC Educational Resources Information Center

Preservice early childhood educators responded in daily reflection journals on their field experience in local elementary classrooms. These journal entries were categorized according to the frequency of the responses. The focus of the study became the nature of the initial impressions that these preservice educators had of their cooperating…

Sweigard, Thomas L.

2009-01-01

240

First impression versus second thought in true-false tests  

Microsoft Academic Search

An analysis of changes of answers in true-false test responses, under ordinary circumstances and under instruction to record both first impression and second thought, shows that correct changes are more frequent than incorrect changes. This performance is not found with a few individuals or with a few questions only.

M. L. Lowe; C. C. Crawford

1929-01-01

241

Handwriting and Students with Disabilities: Overcoming First Impressions.  

ERIC Educational Resources Information Center

Students with disabilities often experience particular difficulties with handwriting, and these problems can hinder their development both in school and in postsecondary settings. This paper addresses three issues: (1) the possibility of a prejudicial and potentially lasting first impression, based on the individual's handwriting; (2) the lack of…

Greenland, Roy; Polloway, Edward A.

242

Forming Impressions About Homosexuals: Does Timing of Disclosure Matter?  

Microsoft Academic Search

Unlike gender, race, or ethnicity, sexual orientation is not necessarily readily identifiable. Because of this, the biases that are associated with prejudice towards members of other groups might not be initially applied to gay men and lesbians. The current work tests whether timing of disclosure of sexual orientation might influence how observers form first impressions of a target individual. Participants

David Michael Buck

2007-01-01

243

Interpetative thinking and impression formation in a prisoner's dilemma game  

Microsoft Academic Search

In three experiments we examined the notion that interpretative thinking guides impression formation when playing a prisoner's dilemma game. In a first experiment, we demonstrated that an interpretation goal is spontaneously triggered upon receiving ambiguous information about an interaction partner in the context of a prisoner's dilemma game. In Experiment 2, we examined whether in this context accessible knowledge is

D Smeesters; Luk Warlop; Eddy Van Avermaet

2002-01-01

244

Attorney communication and impression making in the courtroom  

Microsoft Academic Search

This study investigated the effectiveness of attorney communication and impression making in the courtroom. Trained in-court observers rated attorney presentations for factual and legal informativeness, organization, articulateness, and rapport during the opening statement phase of 50 trials. After the trials, jurors were asked to evaluate the attorneys' overall articulateness. enthusiasm, and likableness during the trial. The attorneys were then questioned

Daniel Linz; Steven Penrod; Elaine McDonald

1986-01-01

245

Cross-Cultural Impression Management: A Cultural Knowledge Audit Model  

ERIC Educational Resources Information Center

|Purpose: Many people moving into a new culture for work or study do so without prior cross-cultural training, yet successful cultural adaptation has important ramifications. The purpose of this paper is to focus on cross-cultural impression management as an element of cultural adaptation. Does cultural adaptation begin by paying strong attention…

Spong, Abigail; Kamau, Caroline

2012-01-01

246

Impressions of Counselors as a Function of Counselor Physical Attractiveness  

ERIC Educational Resources Information Center

Research assessed the effects of counselor physical attractiveness and inter-actions between attractiveness and counselor subject sex. It is suggested that sex of counselor and client may play a more important role independently and in conjunction with attractiveness than does attractiveness alone in influencing impressions and expectations.…

Carter, Jean A.

1978-01-01

247

Combinatorial approach to study the effect of acrylic polyol composition on the properties of crosslinked siloxane-polyurethane fouling-release coatings  

Microsoft Academic Search

The effect of acrylic polyol composition on the properties of crosslinked siloxane-polyurethane coatings was explored. An\\u000a acrylic polyol library was synthesized using batch solution polymerization and characterized using high-throughput gel permeation\\u000a chromatography (Rapid-GPC) and differential scanning calorimetry (DSC). Siloxane-polyurethane coatings were prepared from\\u000a 3-aminopropyl-terminated poly(dimethylsiloxane) (PDMS), the acrylic polyols and a polyisocyanate crosslinker. The siloxane-acrylic-polyurethane\\u000a coatings were tested for mechanical

Robert J. Pieper; Abdullah Ekin; Dean C. Webster; Franck Cassé; James A. Callow; Maureen E. Callow

2007-01-01

248

77 FR 14342 - Polyvinyl Alcohol From Taiwan: Correction to Notice of Opportunity To Request Administrative Review  

Federal Register 2010, 2011, 2012, 2013

...International Trade Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Correction to Notice of Opportunity...administrative review of the antidumping duty order on polyvinyl alcohol from Taiwan. See Antidumping or Countervailing...

2012-03-09

249

40 CFR 61.64 - Emission standard for polyvinyl chloride plants.  

Code of Federal Regulations, 2010 CFR

...false Emission standard for polyvinyl chloride plants. 61.64 Section 61.64 ...National Emission Standard for Vinyl Chloride § 61.64 Emission standard for polyvinyl chloride plants. An owner or operator of a...

2010-07-01

250

40 CFR 61.64 - Emission standard for polyvinyl chloride plants.  

Code of Federal Regulations, 2010 CFR

...false Emission standard for polyvinyl chloride plants. 61.64 Section 61.64 ...National Emission Standard for Vinyl Chloride § 61.64 Emission standard for polyvinyl chloride plants. An owner or operator of a...

2009-07-01

251

76 FR 29527 - National Emission Standards for Hazardous Air Pollutants for Polyvinyl Chloride and Copolymers...  

Federal Register 2010, 2011, 2012, 2013

...proposed polyvinyl chloride and copolymers (PVC) production rules in the Houston, Texas...http://www.epa.gov/ttn/atw/pvc/pvcpg.html...psia--pounds per square inch absolute PVC--polyvinyl chloride and copolymers...

2011-05-20

252

Complexes of polyvinyl alcohol with insoluble inorganic compounds  

NASA Astrophysics Data System (ADS)

Hybrid materials of polyvinyl alcohol-hydroxides/oxides of Be, Mg, Zn, Cd, B, Al, Cr, and Fe have been obtained. The studies have been carried out by the methods of optical spectroscopy, X-ray diffraction, and synchronous thermal analysis. Interpretation of experimental data is presented, presuming that, in systems with zinc, boron, aluminum, chromium, and iron hydroxides/oxides, interpolymeric complexes of polyvinyl alcohol with corresponding polymeric inorganic compounds are formed. They belong to a new class of materials with unusual structure containing chains of inorganic polymers isolated in the organic matrix.

Prosanov, I. Yu.; Bulina, N. V.; Gerasimov, K. B.

2013-10-01

253

Hydrophilic interpenetrating polymer networks of poly(dimethyl siloxane) (PDMS) as biomaterial for cochlear implants.  

PubMed

Poly(dimethyl siloxane) (PDMS) was bulk-modified to develop a new intra-cochlear electrode that can closely hug the inner wall of scala tympani (ST). The hydrophilicity of bulk and surface of PDMS was changed using a sequential method for preparation of interpenetrating polymer networks (IPNs). A series of IPNs, based on PDMS and poly(acrylic acid) (PAAc), was synthesized and characterized by means of attenuated total reflectance Fourier transform infrared spectroscopy, water contact-angle measurement, dynamic mechanical thermal analysis and peel strength tests. The performances of actual-sized fabricated electrodes were assessed inside a transparent model of ST, which was filled with saline. The cell behavior of L929 fibroblasts on materials was studied in vitro. PMID:16689019

Abbasi, F; Mirzadeh, H; Simjoo, M

2006-01-01

254

Sol-Gel Synthesis of Au-Nanoparticle Dispersed Bicontinuous Macroporous Siloxane Gel  

NASA Astrophysics Data System (ADS)

We synthesized Au-nanoparticle dispersed siloxane gel with well-defined bicontinuous macroporous morphologies. We employed methyltrimethoxysilane (MTMS) as a precursor of the gel skeleton, and also employed hydrogen tetrachloroaurate(III) as both a precursor of Au nanoparticles and an acid catalyst for hydrolysis/condensation of methoxysilanes. The effect of adding (3-mercaptopropyl)trimethoxysilane (MPTMS) as a starting material on the obtained structure was also investigated. It is found that Au nanoparticles of 20-30 nm in grain size are uniformly dispersed on the gel surface in the system containing MPTMS; in contrast, Au nanoparticles assembled in the pits in the MPTMS-free system. All the heat-treated MPTMS-containing gels showed surface plasmon absorption, and the peaks shifted from 550 to 520 nm with increasing the calcination temperature.

Hamada, Y.; Nishi, M.; Shimotsuma, Y.; Miura, K.; Hirao, K.

2011-10-01

255

An Investigation of Siloxane Cross-linked Hydroxyapatite-Gelatin/Copolymer Composites for Potential Orthopedic Applications().  

PubMed

Causes of bone deficiency are numerous, but biomimetic alloplastic grafts provide an alternative to repair tissue naturally. Previously, a hydroxyapatite-gelatin modified siloxane (HAp-Gemosil) composite was prepared by cross-linking (N, N'-bis[(3-trimethoxysilyl)propyl]ethylene diamine (enTMOS) around the HAp-Gel nanocomposite particles, to mimic the natural composition and properties of bone. However, the tensile strength remained too low for many orthopedic applications. It was hypothesized that incorporating a polymer chain into the composite could help improve long range interaction. Furthermore, designing this polymer to interact with the enTMOS siloxane cross-linked matrix would provide improved adhesion between the polymer and the ceramic composite, and improve mechanical properties. To this end, copolymers of L-Lactide (LLA), and a novel alkyne derivatized trimethylene carbonate, propargyl carbonate (PC), were synthesized. Incorporation of PC during copolymerization affects properties of copolymers such as molecular weight, T(g), and % PC incorporation. More importantly, PC monomers bear a synthetic handle, allowing copolymers to undergo post-polymerization functionalization with graft monomers to specifically tailor the properties of the final composite. For our investigation, P(LLA-co-PC) copolymers were functionalized by an azido-silane (AS) via copper catalyzed azide-alkyne cycloaddition (CuAAC) through terminal alkyne on PC monomers. The new functionalized polymer, P(LLA-co-PC)(AS) was blended with HAp-Gemosil, with the azido-silane linking the copolymer to the silsesquioxane matrix within the final composite.These HAp-Gemosil/P(LLA-co-PC)(AS) composites were subjected to mechanical and biological testing, and the results were compared with those from the HAp-Gemosil composites. This study revealed that incorporating a cross-linkable polymer served to increase the flexural strength of the composite by 50%, while maintaining the biocompatibility of HAp-Gemosil ceramics. PMID:23139457

Dyke, Jason Christopher; Knight, Kelly Jane; Zhou, Huaxing; Chiu, Chi-Kai; Ko, Ching-Chang; You, Wei

2012-09-01

256

An Investigation of Siloxane Cross-linked Hydroxyapatite-Gelatin/Copolymer Composites for Potential Orthopedic Applications†  

PubMed Central

Causes of bone deficiency are numerous, but biomimetic alloplastic grafts provide an alternative to repair tissue naturally. Previously, a hydroxyapatite-gelatin modified siloxane (HAp-Gemosil) composite was prepared by cross-linking (N, N?-bis[(3-trimethoxysilyl)propyl]ethylene diamine (enTMOS) around the HAp-Gel nanocomposite particles, to mimic the natural composition and properties of bone. However, the tensile strength remained too low for many orthopedic applications. It was hypothesized that incorporating a polymer chain into the composite could help improve long range interaction. Furthermore, designing this polymer to interact with the enTMOS siloxane cross-linked matrix would provide improved adhesion between the polymer and the ceramic composite, and improve mechanical properties. To this end, copolymers of L-Lactide (LLA), and a novel alkyne derivatized trimethylene carbonate, propargyl carbonate (PC), were synthesized. Incorporation of PC during copolymerization affects properties of copolymers such as molecular weight, Tg, and % PC incorporation. More importantly, PC monomers bear a synthetic handle, allowing copolymers to undergo post-polymerization functionalization with graft monomers to specifically tailor the properties of the final composite. For our investigation, P(LLA-co-PC) copolymers were functionalized by an azido-silane (AS) via copper catalyzed azide-alkyne cycloaddition (CuAAC) through terminal alkyne on PC monomers. The new functionalized polymer, P(LLA-co-PC)(AS) was blended with HAp-Gemosil, with the azido-silane linking the copolymer to the silsesquioxane matrix within the final composite. These HAp-Gemosil/P(LLA-co-PC)(AS) composites were subjected to mechanical and biological testing, and the results were compared with those from the HAp-Gemosil composites. This study revealed that incorporating a cross-linkable polymer served to increase the flexural strength of the composite by 50%, while maintaining the biocompatibility of HAp-Gemosil ceramics.

Dyke, Jason Christopher; Knight, Kelly Jane; Zhou, Huaxing; Chiu, Chi-Kai; Ko, Ching-Chang; You, Wei

2012-01-01

257

First impressions: gait cues drive reliable trait judgements.  

PubMed

Personality trait attribution can underpin important social decisions and yet requires little effort; even a brief exposure to a photograph can generate lasting impressions. Body movement is a channel readily available to observers and allows judgements to be made when facial and body appearances are less visible; e.g., from great distances. Across three studies, we assessed the reliability of trait judgements of point-light walkers and identified motion-related visual cues driving observers' judgements. The findings confirm that observers make reliable, albeit inaccurate, trait judgements, and these were linked to a small number of motion components derived from a Principal Component Analysis of the motion data. Parametric manipulation of the motion components linearly affected trait ratings, providing strong evidence that the visual cues captured by these components drive observers' trait judgements. Subsequent analyses suggest that reliability of trait ratings was driven by impressions of emotion, attractiveness and masculinity. PMID:22717166

Thoresen, John C; Vuong, Quoc C; Atkinson, Anthony P

2012-06-18

258

A preliminary study on the properties and fouling-release performance of siloxane–polyurethane coatings prepared from poly(dimethylsiloxane) (PDMS) macromers  

Microsoft Academic Search

Siloxane–polyurethane fouling-release (FR) coatings based on aminopropyl terminated poly(dimethylsiloxane) (PDMS) macromers were prepared and characterized for FR performance via laboratory biological assays. These systems rely on self-stratification, resulting in a coating with a siloxane-rich surface and polyurethane bulk. Previously, these coating systems have used PDMS with multiple functional groups which react into the polyurethane bulk. Here, aminopropyl terminated PDMS macromers

Stacy Sommer; Abdullah Ekin; Dean C. Webster; Shane J. Stafslien; Justin Daniels; Lyndsi J. VanderWal; Stephanie E. M. Thompson; Maureen E. Callow; James A. Callow

2010-01-01

259

X-ray diffraction investigation of siloxanes. III. Structure and configuration of cyclic tetra-and pentasiloxanes bearing different organic substituents at silicon atoms  

Microsoft Academic Search

Single crystal X-ray diffraction is applied to elucidate the structures of six tetra-and one penta-siloxane compounds differing\\u000a in the nature and position of silicon-sitting organic substituents (Me — methyl, Ph — phenyl, mPh — methoxyphenyl, 2mPh —\\u000a dimethoxyphenyl, 3mPh — trimethoxypehnyl, and C4H6N — butironitrile). Charge states of atoms in the siloxane molecules are calculated, and the effect of oxygen-containing

S. T. Malinovskii; A. Tesuro Vallina; H. Stoeckli-Evans

2007-01-01

260

Predicting Trait Impressions of Faces Using Classifier Ensembles  

Microsoft Academic Search

In the experiments presented in this chapter, single classifier systems and ensembles are trained to detect the social meanings\\u000a people perceive in facial morphology. Exploring machine models of people’s impressions of faces has value in the fields of\\u000a social psychology and human-computer interaction. Our first concern in designing this study was developing a sound ground\\u000a truth for this problem domain.

Sheryl Brahnam; Loris Nanni

261

Person and Costume: Effects on the Formation of First Impressions  

Microsoft Academic Search

This exploratory study examined the effects of the stimulus person and the clothing worn by the stimulus person on the formation of first impressions, where the stimulus per son and the observer were female peers. A four-by-four factorial experiment was designed to measure the simultaneous effects of person-costume photographic stimuli on the subjects' initial formation of athletic, social, and intellectual

Barbara Hunt Conner; Kathleen Peters; Richard H. Nagasawa

1975-01-01

262

e-Perceptions: Personality Impressions Based on Personal Websites  

Microsoft Academic Search

This research examined the accuracy of personality impressions based on personal websites, a rapidly growing medium for self-expression, where identity claims are predominant. Eighty-nine websites were viewed by 11 observers, who rated the website authors' personalities. The ratings were compared with an accuracy criterion (self- and informant reports) and with the authors' ideal-self ratings. The websites elicited high levels of

Simine Vazire; Samuel D. Gosling

2004-01-01

263

Preparation of void-free casts from vinyl polysiloxane impressions  

Microsoft Academic Search

Purpose: To investigate two techniques to produce void-free casts from vinyl polysiloxane impressions.Materials and methods: Thirty casts prepared using a conventional technique were compared with 30 casts prepared using a technique involving syringing of stone in terms of numbers of surface voids.Results: Significantly fewer surface voids were observed in the casts prepared using syringing technique.Conclusion: The syringing technique investigated is

H. Sherfudhin; M. A. Abdulla

1996-01-01

264

A thin slice perspective on the accuracy of first impressions  

Microsoft Academic Search

The accuracy of first impressions was examined by investigating judged construct (negative affect, positive affect, the Big five personality variables, intelligence), exposure time (5, 20, 45, 60, and 300s), and slice location (beginning, middle, end). Three hundred and thirty four judges rated 30 targets. Accuracy was defined as the correlation between a judge’s ratings and the target’s criterion scores on

Dana R. Carney; C. Randall Colvin; Judith A. Hall

2007-01-01

265

The relationship of clients’ social class to early therapeutic impressions  

Microsoft Academic Search

Using case vignettes that differed in the presentation of the client's social class, the influence of social class on therapeutic impressions was studied in the context of just-world beliefs. Results suggested that (1) participants with higher levels of belief in a just world saw poor and working-class clients as more unpleasant to work with and more dysfunctional and (2) working-class

Laura Smith; Susan Mao; Seth Perkins; Marilyn Ampuero

2011-01-01

266

Analyzing the aesthetic impressions of alexithymic Japanese students.  

PubMed

We investigated the association between alexithymic tendencies as measured by the 20-item Toronto Alexithymia Scale and the characteristics of aesthetic impressions for words and drawings. Impressions were measured using the semantic differential technique in three groups of Japanese students (High scores n = 31, Moderate scores n = 40, and a Control group n = 182) who were presented only words (Word condition), only drawings (Drawing condition), or pairs comprising one word plus one drawing that represented the same emotional categories (Drawing/Word condition). In a factor analysis on the data from participants, three factors (Evaluation, Activity, and Potency) were extracted. Based on the factor scores, the distances among the three conditions were calculated for each of the groups. For Potency, significant group differences were found between the Drawing/Word and other conditions. In the High-scoring alexithymia group, in particular, the Potency impressions based on tactile sensation, e.g., soft-hard, blunt-sharp, were amplified regardless of stimulus condition. These results are discussed in the context of somatosensory amplification associated with alexithymia and the difficulty of distinguishing between emotion and somatic sensations. PMID:15154201

Suzuki, Miho; Gyoba, Jiro; Kano, Michiko

2004-04-01

267

Color Stabilization of Polyvinyl Chloride) with Heat Treatment  

Microsoft Academic Search

Stabilization of polyvinyl chloride) (PVC) containing metal soaps was investigated by psychophysical colorimetry. A color difference observed among heated PVC films containing various metal salts depends on coloration of the ?-complex of polyene with metal chloride converted from the metal salt added and that the stabilization effect of synergistic soaps should be based on an effect of complementary colors set

Takeo Iida; Kunio Goto

1978-01-01

268

Electrical and thermal properties of polyvinyl acetal based nanocomposites  

Microsoft Academic Search

A water chemistry procedure is used to synthesize titanium dioxide nanoparticles which can later be blended with a polymer to form a nanodielectric. The synthesized nanoparticles are dispersed in two grades of polyvinyl acetal (commercially available under the trade names BX-L and KS-10, manufactured by SEKISUI Chemicals). Nanocomposite materials were prepared with 15 and 33 wt% titanium dioxide. The variation

G. Polizos; E. Tuncer; Isidor Sauers; David Randy James; A. R. Ellis; Marshall O Pace

2009-01-01

269

Review of the oral toxicity of polyvinyl alcohol (PVA)  

Microsoft Academic Search

Polyvinyl alcohols (PVA) (CAS no. 9002-89-5) are synthetic polymers used in a wide range of industrial, commercial, medical and food applications. The purpose of this review, this critical evaluation of the available information on PVA, is to support the safety of PVA as a coating agent for pharmaceutical and dietary supplement products. All the available information on PVA gleaned from

C. C DeMerlis; D. R Schoneker

2003-01-01

270

Vaginal Absorption of Polyvinyl Alcohol in Fischer 344 Rats  

Microsoft Academic Search

Polyvinyl alcohol (PVA) is a polymer with a wide range of molecular weights and uses. Recently, low molecular weight formulations of PVA have been used as components of contraceptive products designed for intravaginal administration in human females. Previous studies in animals have determined that little or no absorption of PVA occurs from the gastrointestinal (GI) tract. However, there is some

J. M. Sanders; H. B. Matthews

1990-01-01

271

Anammox sludge immobilized in polyvinyl alcohol (PVA) cryogel carriers  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study evaluated the use of polyvinyl alcohol (PVA) cryogels to encapsulate slow-growing anammox bacteria for deammonification treatment of wastewater. The cryogel pellets were prepared by a freezing-thawing procedure at -8 oC. On average, pellets contained 11.8 mg TSS/g-pellet of enriched anamm...

272

Immobilization of enzymes in photochemically cross-linked polyvinyl alcohol  

Microsoft Academic Search

Invertase and amyloglucosidase were entrapped in polyvinyl alcohol membranes through UV irradiation of pendent styrylpyridinium groups. The influence of cross-linking on immobilization efficiency was studied using prepolymers with varied cross-linker density, the above mentioned enzymes of different molecular weight, and various substrates. It was found that the larger enzyme invertase is effectively immobilized even in polymers with very low contents

Thomas Uhlich; Mathias Ulbricht; Georg Tomaschewski

1996-01-01

273

Biodegradation of a polyvinyl alcohol-starch blend plastic film  

Microsoft Academic Search

Attempts were made to elucidate the degradation mechanism of a polyvinyl alcohol (PVA)-starch blend plastic. A part of the starch fraction of this plastic was dissolved into an aqueous phase in a control test. Treatment with a PVA-degrading bacterium or enzyme gave a maximal weight loss of approximately 70% and film breakage occurred. Since this plastic contains 40% PVA, it

Tomonori Ishigaki; Yasunori Kawagoshi; Michihiko Ike; Masanori Fujita

1999-01-01

274

Immobilization of microbial cells using polyvinyl alcohol (PVA) — polyacrylamide gels  

Microsoft Academic Search

A novel cell immobilization technique is developed in which polyvinyl alcohol is crosslinked with boric acid with addition of an acrylamide as a polymerizing agent. The presence of the polymerizing agent overcomes the problem of swelling of PVA gels in aqueous solution. The new immobilization method was used to entrap a phenol-degrading microorganism, a species of Pseudomonas. Phenol was successfully

Wang Jianlong; Hou Wenhua; Qian Yicr

1995-01-01

275

Polyvinyl Alcohol from Taiwan. Investigation No. 731-TA-1088 (Preliminary).  

National Technical Information Service (NTIS)

The United States International Trade Commission (ITC) determined that there is not a reasonable indication that a U.S. industry is materially injured or threatened with material injury by reason of imports of polyvinyl alcohol from Taiwan that are allege...

2004-01-01

276

Crack formation in polyvinyl chloride coatings on underground pipes  

Microsoft Academic Search

and certain other agents, for a polymeric coating on a tube in the soil, other specific features are also characteristic. Results have previously been presented [1, 2] of a study of polyvinyl chloride coatings kept for a prolonged period under different underground conditions. The investigations were concerned with oxidative processes under the influence of the molecular oxygen of the air

B. I. Borisov; CHLORIDE COATINGS

1975-01-01

277

Hot pin welding of thin poly(vinyl chloride) sheet  

Microsoft Academic Search

This paper develops a method of welding two thin sheets of poly(vinyl chloride) (PVC) with a heated pin, thus allowing construction of a relationship between the weld temperature and weld strength. Constructing a relationship between weld strength and temperature is necessary for modeling many welding processes, including laser transmission welding. An experimental approach to establishing this relationship is required because

James D. Van de Ven; Arthur G. Erdman

2007-01-01

278

Influence of urea on polyvinyl alcohol molecular superstructure formation  

NASA Astrophysics Data System (ADS)

Whiskers up to 1 cm in length were grown in polyvinyl alcohol (PVA) and urea solution. Raman and IR spectra discover an interaction between PVA and urea molecules. Optical and electronic microscopy data show that urea influences on PVA molecular superstructure formation. PVA whiskers prepared in urea solution can be used for organic semiconductors production which properties are determined by arrangement of polymer macromolecules.

Prosanov, I. Yu.; Matvienko, A. A.; Bokhonov, B. B.

2011-06-01

279

EXPOSURE TO CHEMICAL ADDITIVES FROM POLYVINYL CHLORIDE POLYMER EXTRUSION PROCESSING  

EPA Science Inventory

This report presents a model to predict worker inhalation exposure due to off-gassing of additives during polyvinyl chloride (PVC) extrusion processing. ata on off-gassing of additives were reviewed in the literature, the off-gassing at normal PVC processing temperatures was stud...

280

The Goal of Forming Accurate Impressions During Social Interactions: Attenuating the Impact of Negative Expectancies  

Microsoft Academic Search

Investigated the idea that impression formation goals may regulate the impact that perceiver expectancies have on social interactions. In simulated interviews, interviewer Ss were given a negative expectancy about one applicant S and no expectancy about another. Half the interviewers were encouraged to form accurate impressions; the others were not. As predicted, no-goal interviewers exhibited a postinteraction impression bias against

Steven L. Neuberg

1989-01-01

281

Computer-Mediated Impression Formation: A Test of the Sticky Cues Model Using Facebook  

ERIC Educational Resources Information Center

|This research offers a model of online impression formation that explains how different impression-bearing cues may carry more or less informational value. This research considers the possibility that impression-bearing cues have greater informational value when those cues are distinctive and are task-relevant. This research refers to such cues…

Van Der Heide, Brandon Lee

2009-01-01

282

Impression management : Developing and illustrating a scheme of analysis for narrative disclosures – a methodological note  

Microsoft Academic Search

Purpose – This paper aims to develop a holistic measure for analysing impression management and for detecting bias introduced into corporate narratives as a result of impression management. Design\\/methodology\\/approach – Prior research on the seven impression management methods in the literature is summarised. Four of the less-researched methods are described in detail, and are illustrated with examples from UK annual

Niamh M. Brennan; Encarna Guillamon-Saorin; Aileen Pierce

2009-01-01

283

Managing an Attractive Impression by Using Alcohol: Evidence From Two Daily Diary Studies  

Microsoft Academic Search

Two studies investigate impression management processes and alcohol use. In both studies, participants completed the Fear of Negative Evaluation scale and then a 21-day survey. In Study 1, participants reported daily desired impression and drinking. Men drank more than women; however, this effect was stronger on days in which they wanted to appear attractive as compared to other desired impressions.

Megan A. OGrady; Jennifer J. Harman; Marci E. J. Gleason; Kristina Wilson

2012-01-01

284

From visible to white-light emission by siloxane-capped ZnO quantum dots upon interaction with thiols  

NASA Astrophysics Data System (ADS)

The interaction of thiols (glutathione, cysteine, and cysteamine) with yellow-emitting siloxane-capped ZnO QDs was studied. A gradual enlargement of the PL emission band resulting in white-light emission was observed upon reaction with thiols, while the diameter (ca. 4 nm) and the crystallinity of the dots were not affected. The appearance of broad white-emission was accompanied by a decrease of the photoluminescence quantum yield from 16% to 5-6%. Generation of surface defect states through interaction of the thiols with Zn surface atoms of the dots provoking shrunk of the siloxane capping may be responsible of that broadband emission throughout most of the light spectrum.

Schejn, Aleksandra; Balan, Lavinia; Piatkowski, Dawid; Mackowski, Sebastian; Lulek, Janina; Schneider, Raphaël

2012-06-01

285

Miscible Blends of Poly(siloxane Imide) Segmented Copolymers and Polybenzimidazole as Potential High Performance Aerospace Materials  

Microsoft Academic Search

Compatible blends of high performance engineering thermoplastics have been investigated for aerospace applications, where stability in an aggressive atomic oxygen environment is of significant concern. The blends were comprised of polyimide homopolymers and poly(siloxane imide) segmented copolymers based upon benzophe-none tetracarboxylic dianhydride (BTDA) and m-diaminodiphenyl sulfone, and polybenzimidazole (PBI). The blends exhibited glass transition temperatures in excess of 300°C, and

C. A. Arnold; D. H. Chen; Y. P. Chen; R. O. Waldbauer; M. E. Rogers; J. E. McGrath

1990-01-01

286

Improvement of thermal conductivity of poly(dimethyl siloxane) using silica-coated multi-walled carbon nanotube  

Microsoft Academic Search

In order to enhance the thermal conductivity of MWCNT filled poly(dimethyl siloxane) (PDMS) composites, the MWCNT was coated\\u000a with silica layer by three step reactions. The composites filled with raw and silica-coated MWCNTs were prepared and the properties\\u000a were investigated in terms of the curing characteristics, mechanical properties, and thermal conductivity. Due to the poor\\u000a compatibility between raw MWCNT and

Jinho Hong; Jeongwoo Lee; Chang Kook Hong; Sang Eun Shim

2010-01-01

287

Effects of pigmentation on siloxane–polyurethane coatings and their performance as fouling-release marine coatings  

Microsoft Academic Search

Siloxane–polyurethane paints were formulated and characterized for coating properties and performance as fouling-release (FR)\\u000a marine coatings. Paints were formulated at 20 and 30 pigment volume concentrations with titanium dioxide, and aminopropyl-terminated\\u000a poly(dimethylsiloxane) (APT-PDMS) loadings were varied from 0 to 30% based on binder mass. The coatings were characterized\\u000a for water contact angle, surface energy (SE), gloss, and pseudobarnacle (PB) adhesion.

Stacy A. Sommer; Joseph R. Byrom; Hanna D. Fischer; Rajan B. Bodkhe; Shane J. Stafslien; Justin Daniels; Carolyn Yehle; Dean C. Webster

288

Implantation of a new porous gelatin–siloxane hybrid into a brain lesion as a potential scaffold for tissue regeneration  

Microsoft Academic Search

For brain tissue regeneration, any scaffold for migrated or transplanted stem cells with supportive angiogenesis is important once necrotic brain tissue has formed a cavity after injury such as cerebral ischemia. In this study, a new porous gelatin–siloxane hybrid derived from the integration of gelatin and 3-(glycidoxypropyl) trimethoxysilane was implanted as a three-dimensional scaffold into a defect of the cerebral

Kentaro Deguchi; Kanji Tsuru; Takeshi Hayashi; Mikiro Takaishi; Mitsuyuki Nagahara; Shoko Nagotani; Yoshihide Sehara; Guang Jin; HanZhe Zhang; Satoshi Hayakawa; Mikio Shoji; Masahiro Miyazaki; Akiyoshi Osaka; Nam-Ho Huh; Koji Abe

2006-01-01

289

Surface Modification of Sylgard-184 Poly(dimethyl siloxane) Networks by Ultraviolet and Ultraviolet\\/Ozone Treatment  

Microsoft Academic Search

We report on the surface modification of Sylgard-184 poly(dimethyl siloxane) (PDMS) networks by ultraviolet (UV) radiation and ultraviolet\\/ozone (UVO) treatment. The effects of the UV light wavelength and ambient conditions on the surface properties of Sylgard-184 are probed using a battery of experimental probes, including static contact angle measurements, Fourier transform infrared spectroscopy, near-edge X-ray absorption fine structure, and X-ray

Kirill Efimenko; William E. Wallace; Jan Genzer

2002-01-01

290

Cost-effective and reliable sealing method for PDMS (PolyDiMethylSiloxane)-based microfluidic devices with various substrates  

Microsoft Academic Search

A cost-effective and simply handling bonding method using siloxane-based adhesion promoter is introduced to increase the adhesion\\u000a strength between cured PDMS and various substrates. The working mechanism of adhesion promoters is based on post-cure reaction\\u000a in PDMS curing and they have similar chemistry compositions with PDMS prepolymers. It is experimentally investigated and proved\\u000a that the adhesion strength of the resulted

Dengke Cai; Andreas Neyer

2010-01-01

291

Synthesis and characterization of organic-inorganic hybrid clay filled and bismaleimide—siloxane modified epoxy nanocomposites  

Microsoft Academic Search

Organic-inorganic hybrids involving organo-modified montmorillonite (OMMT) clay and tetraglycidyl diamino diphenyl methane\\u000a epoxy (TGDDM) were prepared via in situ polymerization by the homogeneous dispersion of various percentages (1–5% w\\/w) of\\u000a clay in epoxy matrix resin. The resulting homogeneous epoxy—clay hybrids were modified with 10 wt% of hydroxyl terminated\\u000a polydiemthyl siloxane (HTPDMS) using ?—aminopropyltriethoxysilane (?-APS) as coupling agent in the presence of

Selvaganapathi Anbazhagan; Muthukaruppan Alagar; Periyannan Gnanasundaram

292

Purification of landfill biogases from siloxanes by adsorption: A study of silica and 13X zeolite adsorbents on hexamethylcyclotrisiloxane separation  

Microsoft Academic Search

The adsorption capacity on and the desorption from pure activated carbons, silica and NaX zeolite, of hexamethylcyclotrisiloxane (HMCTS or D3, a common siloxane impurity in biogases) has been evaluated in laboratory experiments using synthetic biogas. The adsorption mode of this molecule has also been investigated by FT-IR spectroscopy. HMCTS adsorbs on silica by hydrogen bonding on the surface hydroxyl groups.

Tania Montanari; Elisabetta Finocchio; Irene Bozzano; Gilberto Garuti; Andrea Giordano; Chiara Pistarino; Guido Busca

2010-01-01

293

Determination of siloxanes and VOC in landfill gas and sewage gas by canister sampling and GC-MS/AES analysis  

SciTech Connect

Biogases such as landfill gas and sewage gas undergo a combustion process which is generating electric energy. Since several trace compounds such as siloxanes (also halogenated and sulfur compounds) are known to cause severe problems to these gas combustion engines, they are of particular interest. In this work, a new technique for sampling, identification, and quantification of siloxanes and volatile organic carbon (VOC) in landfill gas and sewage gas is presented. After sample collection using evacuated stainless steel canisters biogas was analyzed by gas chromatography-mass spectrometry/atomic emission spectroscopy (GC-MS/AES). Using gas canisters, the sampling process was simplified (no vacuum pump needed), and multiple analysis was possible. The simultaneous application of MSD and AED allowed a rapid screening of silicon compounds in the complex biogases. Individual substances were identified independently both by MSD analysis and by determination of their elemental constitution. Quantification of trace compounds was achieved using a 30 component external standard containing siloxanes, organochlorine and organosulfur compounds, alkanes, terpenes, and aromatic compounds. Precision, linearity, and detection limits have been studied. In real samples, concentrations of silicon containing compounds (trimethylsilanol, hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasilioxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane) in the mg/m{sub 3} range have been observed.

Schweigkofler, M.; Niessner, R.

1999-10-15

294

Pilot study on accuracy and dimensional stability of impression materials using industrial CT technology  

Microsoft Academic Search

Objective  Using computed tomography, scan impressions can be saved and edited as virtual data. The aim of this study was to evaluate\\u000a the parameters influencing different impression materials and impression trays and their relevance with regard to accuracy\\u000a and dimensional stability.\\u000a \\u000a \\u000a \\u000a \\u000a Materials and methods  Two alginate impressions (Zhermack Hydrogum®5 and Kaniedenta Tetrachrom®) and a polyether impression (3MEspe Impregum™) were\\u000a each combined with

Stefanie Steinhäuser-Andresen; Andreas Detterbeck; Christoph Funk; Michael Krumm; Stefan Kasperl; Alexandra Holst; Ursula Hirschfelder

2011-01-01

295

Vertical displacement of distal-extension ridges by different impression techniques.  

PubMed

A study was conducted to compare tissue displacement resulting from different techniques and impression materials for distal-extension ridges. Impression techniques used were Applegate's functional fluid wax and a single-impression technique with mercaptan rubber. A mucostatic impression technique using irreversible hydrocolloid served as control. The results showed a statistically significant difference in tissue displacement between the casts made from the functional fluid wax technique and the single-impression technique with mercaptan rubber and the casts in the control group. PMID:359787

Vahidi, F

1978-10-01

296

High-rate thermomechanical behavior of poly(vinyl chloride) and plasticized poly(vinyl chloride)  

NASA Astrophysics Data System (ADS)

A combined experimental and analytical investigation was carried out in order to develop predictive capabilities for the rate-dependent behavior of poly(vinyl chloride) (PVC) and a dioctyl phthalate (DOP)-plasticized PVC, with focus on predicting the thermo-mechanically coupled behavior under high rates of deformation. The two materials were studied experimentally using both dynamic mechanical analysis (DMA) and compression testing over a wide range of strain rates (10 - 4 s - 1 to 2000 s - 1). DMA testing revealed both an ? -transition and a low-temperature ? -transition (-56circC) in the neat PVC; the incorporation of 20wt% DOP in PVC reduced the ? -transition temperature by 54circC, and also suppressed the ? -transition peak. In compression testing, rate-sensitivity transitions were observed in both the neat PVC and the PVC-20wt% DOP compound. The transition in PVC is attributed to the shift of the ? -transition, whereas the transition in the 20wt% DOP blend is due to the rubbery-to-glassy transition as the deformation rate goes from low to high. A constitutive model for the finite strain deformation of amorphous polymers, introduced elsewhere [1,2] and tailored here for the two material systems of interest, is shown to capture the large deformation stress-strain behavior at all rates tested.

Mulliken, A. D.; Soong, S. Y.; Boyce, M. C.; Cohen, R. E.

2006-08-01

297

Remembering first impressions: effects of intentionality and diagnosticity on subsequent memory.  

PubMed

People rely on first impressions every day as an important tool to interpret social behavior. While research is beginning to reveal the neural underpinnings of first impressions, particularly through understanding the role of dorsal medial prefrontal cortex (dmPFC), little is known about the way in which first impressions are encoded into memory. This is surprising because first impressions are relevant from a social perspective for future interactions, requiring that they be transferred to memory. The present study used a subsequent-memory paradigm to test the conditions under which the dmPFC is implicated in the encoding of first impressions. We found that intentionally forming impressions engages the dmPFC more than does incidentally forming impressions, and that this engagement supports the encoding of remembered impressions. In addition, we found that diagnostic information, which more readily lends itself to forming trait impressions, engages the dmPFC more than does neutral information. These results indicate that the neural system subserving memory for impressions is sensitive to consciously formed impressions. The results also suggest a distinction between a social memory system and other explicit memory systems governed by the medial temporal lobes. PMID:22139633

Gilron, Roee; Gutchess, Angela H

2012-03-01

298

Chemical enhancement of footwear impressions in blood on fabric - part 3: amino acid staining.  

PubMed

Enhancement of footwear impressions, using ninhydrin or ninhydrin analogues is not considered common practice and such techniques are generally used to target amino acids present in fingermarks where the reaction gives rise to colour and possibly fluorescence. Ninhydrin and two of its analogues were used for the enhancement of footwear impressions in blood on various types, colours and porosities of fabric. Test footwear impressions on fabric were prepared using a specifically built rig to minimise the variability between each impression. Ninhydrin enhancement of footwear impressions in blood on light coloured fabric yielded good enhancement results, however the contrast was weak or non-existent on dark coloured fabrics. Other ninhydrin analogues which have the advantage of fluorescence failed to enhance the impressions in blood on all fabrics. The sequential treatment of impressions in blood on fabric with other blood enhancing reagents (e.g. protein stains and heme reagents) was also investigated. PMID:23380056

Farrugia, Kevin J; Bandey, Helen; Savage, Kathleen; NicDaéid, Niamh

2012-09-13

299

A comparison of dimensional accuracy between three different addition cured silicone impression materials.  

PubMed

Ten impressions of a metal implant abutment were made with each of three addition-cured silicone impression materials. Using the technique of co-ordinate metrology, the shoulder region of the abutment and corresponding regions of both impressions and dies made from these impressions were scanned and measured. Comparison of these measurements indicated that the mean dimension measured from the shoulder region for each group of impression materials was significantly different from those taken from the original metal implant abutment. However, when these impressions were cast in a gypsum based die material, none of the measured dimensions taken from the casts were significantly different from those taken from the original metal implant abutment. Thus, any change in measured dimensions occurring during impression making, was compensated for in some way by the casting process. PMID:16011234

Forrester-Baker, L; Seymour, K G; Samarawickrama, D; Zou, L; Cherukara, G; Patel, M

2005-06-01

300

Functionalized siloxane-based polymers and network materials for second-order nonlinear optics  

NASA Astrophysics Data System (ADS)

We have developed a new chemical methodology, based on simple acid-base hydrolysis of aminosilanes with molecules containing terminal OH groups, to prepare robust siloxane based polymers and organic-inorganic hybrid network materials for second-order nonlinear optics. First, a variety of polymers containing NLO- active chromophores covalently bound to the siloxane backbones, [-R2Si-(O- SiR2)n-O-(NLO-Chromophore)-O-] n (R = CH3 or CH3/C6H4) and [- R2Si-(O-SiR2)n-O- R'-O-(NLO-Chromophore)-O-] n. (R' = -C6H4-C 6H4- C6H4-), were prepared. Their solubility in common organic solvents, and high thermal stability, imparted ease of thin film preparation, and subsequent poling at high temperatures. These polymers exhibit good second-harmonic generation susceptibilities, and the temporal stabilities of the SHG signals were dependent on the polymer backbone and the molecular structures of the NLO chromophoms. A detailed analysis of their physical properties is reported. Then, a methodology of acid-base hydrolysis was used to produce copolymers containing dimethylsiloxane, imide linkages and NLO-active chromophores. These copolymers were soluble in polar solvents, and possessed high thermal stabilities and glass transition temperatures. Easily fabricated and poled thin films of these polymers exhibited good second-order nonlinear optical susceptibilities with long-term temporal stabilities of the second-harmonic generation signals at room temperature. Finally, an alternative approach, based on the same acid-base hydrolysis technique, to prepare organic-inorganic hybrid network material, was developed. In these hybrid materials, NLO-active chromophores such as Disperse Red 19, a pyridinium. salt based dye, and 1- amino-4-nitrobenzene, were covalently locked into silica networks. The hybrids were soluble, and offered ease of processibility in the preparation of good optical quality thin films. The network materials that are akin to the traditional sol-gel approach were also prepared from the monofunctional NLO chromophore DRI and as expected, were found to be insoluble in common organic solvents. Physical properties of NLO-chromophore incorporated hybrids were tailored by changing the amount of chromophores and water used in hydrolysis, and the type of chromophores. High thermal stability and glass transition temperatures of these hybrids provided effective electric-field poling at high temperatures, and long-term temporal stabilities of the second-harmonic generation signals at room temperature and 80°C.

Jiang, Hongwei

301

Accuracy of five implant impression technique: effect of splinting materials and methods  

PubMed Central

PURPOSE The aim of this study was to evaluate the effect of dimensional stability of splinting material on the accuracy of master casts. MATERIALS AND METHODS A stainless steel metal model with 6 implants embedded was used as a master model. Implant level impressions were made after square impression copings were splinted using 5 different techniques as follows. (1) Splinted with autopolymerizing resin and sectioned, reconnected to compensate polymerization shrinkage before the impression procedure. (2) Splinted with autopolymerizing resin just before impression procedure. (3) Primary impression made with impression plaster and secondary impression were made over with polyether impression material. (4) Splinted with impression plaster. (5) Splinted with VPS bite registration material. From master model, 5 impressions and 5 experimental casts, total 25 casts were made for each of 5 splinting methods. The distortion values of each splinting methods were measured using coordinate measuring machine, capable of recordings in the x-, y-, z-axes. A one-way analysis of variance (ANOVA) at a confidence level of 95% was used to evaluate the data and Tukey's studentized range test was used to determine significant differences between the groups. RESULTS Group 1 showed best accuracy followed by Group 3 & 4. Group 2 and 5 showed relatively larger distortion value than other groups. No significant difference was found between group 3, 4, 5 in x-axis, group 2, 3, 4 in y-axis and group 1, 3, 4, 5 in z-axis (P<.0001). CONCLUSION Both Splinting impression copings with autopolymerizing resin following compensation of polymerization shrinkage and splinting method with impression plaster can enhance the accuracy of master cast and impression plaster can be used simple and effective splinting material for implant impression procedure.

Cho, Sung-Bum

2011-01-01

302

Orthotic design and foot impression procedures to control foot alignment.  

PubMed

The traditional theory on subtalar joint neutral position and intrinsic foot deformities for the evaluation and treatment of foot and ankle disorders has been the basis for foot orthotics for many years. Although clinical evaluations have suggested a relationship between subtalar pronation and a variety of lower limb problems, such as shin splints and anterior knee pain, recent research has raised serious concerns about the reliability and validity of the assessment and intervention methods. Results of recent studies in foot biomechanics suggest that the orthosis design to control foot alignment should stabilise the medial apical bony structure of the arch to control the first ray mobility and transmit load through the lateral support structures of the foot, locking the calcaneocuboid joint and decreasing strain in the plantar aponeurosis. The concept of "posting" according to a measured foot deformity is de-emphasised. Reliable foot impression procedures are required to provide appropriate orthotic design and thus management. A prone lying position manipulated foot impression method using polycaprolactone based low temperature thermoplastic material was introduced. Ten (10) subjects were recruited to participate in the reliability tests, which were conducted by 2 orthotists specialized in foot orthotics. Results showed high intrarater and interrater reliability of the measured forefoot width and the navicular height. The reliability of the forefoot-rearfoot relationship was demonstrated by the small variance of the root mean square calculation. Subsequently orthotic intervention can be done in a more consistent manner. PMID:15658638

Leung, A K L; Cheng, J C Y; Mak, A F T

2004-12-01

303

Micropatterned polyvinyl butyral membrane for acid-base diodes.  

PubMed

Until now, polyvinyl alcohol (PVA) gel cylinders have been used in electrolyte diodes as a connecting element between the acidic and alkaline reservoirs. In this paper, a new connecting element is reported: a breath figure templated polyvinyl butyral (PVB) membrane prepared with dip-coating from a dichloromethane solution of the polymer in a humid atmosphere. The procedure gives a 1.5-2 ?m thick membrane with a hexagonal pattern, the average characteristic length of which is 1 ?m. After an acidic etching, it was found to be a good connecting element. The voltage-current characteristics and dynamic properties of PVA and PVB were measured and compared. The PVB membrane has a faster response to voltage changes than the PVA gel, but in both cases, there was a slow drift in the current that prevented it from reaching a steady state. Reproducible characteristics can be obtained, however, after the current reaches a well-defined quasi-steady state. PMID:20929271

Roszol, László; Lawson, Thuy; Koncz, Viktória; Noszticzius, Zoltán; Wittmann, Maria; Sarkadi, Tamás; Koppa, Pál

2010-11-01

304

Cross-linked polyvinyl alcohol films as alkaline battery separators  

Microsoft Academic Search

Cross-linking methods were investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: (1) PVA-dialdehyde blends post-treated with an acid or acid periodate solution (two-step method) and (2) PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid

D. W. Sheibley; M. A. Manzo; O. D. Gonzalez-Sanabria

1982-01-01

305

Cross-linked polyvinyl alcohol films as alkaline battery separators  

Microsoft Academic Search

Cross-linking methods have been investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: PVA-dialdehyde blends post-treated with an acid or acid periodate solution and PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality. Laboratory samples

Dean W. Sheibley; O. D. Gonzalez-Sanabria; M. A. Manzo

1983-01-01

306

Nanophotothermolysis of Poly-(vinyl) Alcohol Capped Silver Particles  

NASA Astrophysics Data System (ADS)

Laser-induced thermal fusion and fragmentation of poly-(vinyl) alcohol (PVA)-capped silver nanoparticles in aqueous medium have been reported. PVA-capped silver nanoparticles with an average size of 15 nm were prepared by chemical reduction technique. The laser-induced photo-fragmentation of these particles has been monitored by UV-visible spectroscopy and transmission electron microscopy. The morphological changes induced by thermal and photochemical effects were found to influence the optical properties of these nanoparticles.

Tripathy, Suraj Kumar

2008-04-01

307

The distribution of sequences in partially hydrolysed polyvinylic alcohol  

Microsoft Academic Search

The block copolymer structure of partially hydrolysed polyvinyl alcohol was investigated by DSC: This structure was revealed by the dependence of the melting point of crystalline phase against the composition of vinyl alcohol-vinyl acetate copolymers (VOH-VAc) synthesised by different methods. Using the Flory equation, the sequential probabilities pVOH and pVAc representing quantitative values of the sequences distribution along the chain

Iulia Pocsan; Sever Serban; Gheorghe Hubca; Mihai Dimonie; Horia Iovu

1997-01-01

308

Electrical conductivity of polyvinyl alcohol-multiwall carbon nanotubes composites  

NASA Astrophysics Data System (ADS)

The dc and ac conductivity of polyvinyl alcohol (PVA)-multiwalled carbon nanotube (MWNT) nanocomposites prepared by solution casting were investigated by employing dielectric relaxation spectroscopy in broad frequency range (0.1 Hz-10 MHz) at room temperature as a function of the conductive weight fraction (p) ranging from 0 to 2wt.%. The frequency dependence of the measured conductivity obeys the universal dynamic response (UDR); a dc plateau followed, by the power law above a critical frequency (fc).

Amrin, Sayed; Deshpande, V. D.

2013-06-01

309

Chromate reduction by Microbacterium liquefaciens immobilised in polyvinyl alcohol  

Microsoft Academic Search

A polyvinyl alcohol-based immobilisation technique has been utilised for entrapping the newly-isolated chromate- reducing bacterium, Microbacterium liquefaciensMP30. Three immobilisation methods were evaluated: PVA- nitrate, PVA-borate and PVA-alginate. Chromate reduction was studied in batch and continuous-flow bioreactors, where the beads maintained integrity during continuous operation. PVA-borate and PVA-alginate cell beads showed a higher rate and extent of chromate reduction than PVA-nitrate

P. Pattanapipitpaisal; N. L. Brown; L. E. Macaskie

2001-01-01

310

Surface acoustic wave humidity sensor using polyvinyl-alcohol film  

Microsoft Academic Search

A surface acoustic wave (SAW) sensor has been fabricated and used to study the hygroscopic properties of the polyvinyl-alcohol (PVA) polymer film as layer chemically sensitive to relative humidity (RH). A 42 MHz SAW device has been configured as delay line onto 128° YX-LiNbO3 substrate with the SAW path totally covered by the spin-coated PVA film. The SAW phase response

M. Penza; V. I. Anisimkin

1999-01-01

311

Hybrid material polyvinyl alcohol-stannic acid/stannic oxide  

NASA Astrophysics Data System (ADS)

Hybrid materials polyvinyl alcohol (PVA)-stannic acid and PVA-SnO2 were produced in the form of transparent films. Their investigations by means of optical spectroscopy, X-ray analysis, thermo-gravimetry, and mass-spectrometry were carried out as well as electrical measurements. The model is discussed where the polymeric chains of inorganic constituent are linked by coordinative bonds with carbon polymeric chains. Photoconductivity of PVA-SnO2 was discovered.

Prosanov, I. Yu.; Chesalov, Yu. A.; Gerasimov, K. B.; Bulina, N. V.

2013-07-01

312

Heterogeneous photocatalytic oxidation of polyvinyl alcohol in water  

Microsoft Academic Search

Titanium dioxide mediated photocatalytic degradation of polyvinyl alcohol (PVA) was studied in an annular photoreactor with two 6W (Emax=365nm) UV lamps as light source. In the presence of both TiO2 and light, and initial concentration of 30mg\\/l, 55.3% of PVA was found to degrade after an hour. The effects of initial concentration, pH and the addition of H2O2 on the

Yingxu Chen; Zhenshi Sun; Ye Yang; Qiang Ke

2001-01-01

313

Poly(vinyl alcohol) hydrogels as soft contact lens material  

Microsoft Academic Search

A new type of soft contact lens was developed from the poly(vinyl alchol) (PVA) hydrogel prepared by a low temperature crystallization technique using a water-dimethyl sulfoxide mixed solvent. The PVA contact lens materials had a water content of 78% and a tensile strength of 50 kg\\/cm, five times as strong as that of commercial poly(2-hydroxyethyl methacrylate) soft contact lens. The

Suong-Hyu Hyon; Won-Ill Cha; Yoshito Ikada; Mihori Kita; Yuichiro Ogura; Yoshihito Honda

1994-01-01

314

Chromate reduction by Microbacterium liquefaciens immobilised in polyvinyl alcohol  

Microsoft Academic Search

A polyvinyl alcohol-based immobilisation technique has been utilised for entrapping the newly-isolated chromate-reducing bacterium, Microbacterium liquefaciens MP30. Three immobilisation methods were evaluated: PVA-nitrate, PVA-borate and PVA-alginate. Chromate reduction was studied in batch and continuous-flow bioreactors, where the beads maintained integrity during continuous operation. PVA-borate and PVA-alginate cell beads showed a higher rate and extent of chromate reduction than PVA-nitrate cell

P. Pattanapipitpaisal; N. L. Brown; L. E. Macaskie

2001-01-01

315

Heat capacity of poly(vinyl methyl ether)  

Microsoft Academic Search

The heat capacity of poly(vinyl methyl ether) (PVME) has been measured using adiabatic calorimetry and temperature-modulated differential scanning calorimetry (TMDSC). The heat capacity of the solid and liquid states of amorphous PVME is reported from 5 to 360 K. The amorphous PVME has a glass transition at 248 K (-25 C). Below the glass transition, the low-temperature, experimental heat capacity

Marek Pyda; K. Van Durme; Bernhard Wunderlich; B. Van Mele

2005-01-01

316

Thermal degradation of poly(vinyl butyral) laminated safety glass  

Microsoft Academic Search

The effect of thermal treatment on the chemical structure of plasticized poly(vinyl butyral) (PVB) laminated safety glass was investigated in the temperature range 50–200 °C using infra-red spectroscopy and viscosity measurements. The infra-red spectra showed a large reduction in both the residual hydroxyl and acetate groups present in PVB, together with the complete disappearance of the cyclic acetal group. Moreover,

Nabil M. Safy El-Din; Magdy W. Sabaa

1995-01-01

317

Immobilization of enzyme into poly(vinyl alcohol) membrane  

Microsoft Academic Search

Glucoamylase, invertase, and cellulase were entrapped within poly(vinyl alcohol) (PVA) membrane cross-linked by means of irradiation of ultraviolet light. The conditions for immobilization of glucoamylase were examined with respect to enzyme concentration in PVA, sensitizer (sodium benzoate) concentration in PVA, irradiation time, and membrane thickness. Various characteristics of immobilized glucoamylase were evaluated. Among them, the pH activity curve for the

Kiyokazu Imai; Tomoo Shiomi; Kozo Uchida; Masamitsu Miya

1986-01-01

318

Synthesis of a mesoporous silica hollow microsphere using polyvinyl alcohol  

Microsoft Academic Search

A mesoporous silica hollow microsphere was synthesized in the presence of polyvinyl alcohol for the first time. The synthesized material was characterized by various instrumental techniques such as small-angle X-ray scattering, scanning electron microscopy, transmission electron microscopy, N2 adsorption measurement and Fourier transform infrared spectroscopy. I have succeeded in incorporating an Ultraviolet ray absorber, 2, 2´, 4, 4´ tetrahydroxy benzophenone

N. Venkatathri

2008-01-01

319

Influence of urea on polyvinyl alcohol molecular superstructure formation  

Microsoft Academic Search

Whiskers up to 1 cm in length were grown in polyvinyl alcohol (PVA) and urea solution. Raman and IR spectra discover an interaction\\u000a between PVA and urea molecules. Optical and electronic microscopy data show that urea influences on PVA molecular superstructure\\u000a formation. PVA whiskers prepared in urea solution can be used for organic semiconductors production which properties are determined\\u000a by

I. Yu. Prosanov; A. A. Matvienko; B. B. Bokhonov

2011-01-01

320

Preparation and characterization of core/shell particles with siloxane in the shell  

NASA Astrophysics Data System (ADS)

The core/shell particles consisting of polystyrene core and 3-(methacryloxypropyl)-trimethoxysilane (MPS) shell were prepared in the present study by successive seeding polymerization under kinetically controlled conditions and were characterized by particle size analyser, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The TEM image indicated that the particles containing organic siloxane presented an evident core/shell structure. Additionally, the study of XPS also revealed that MPS could be grafted onto the surface of polystyrene microspheres and the atomic ratio of C/Si on the surface of the core/shell particles (MPS-40) was very close to the ratio of C/Si in the molecule of MPS. The surface properties of the films produced from the core/shell particles were also investigated by the static contact angle method. Compared with the homopolymer of PS, the core/shell particles were more effective to create hydrophobic surface, so, the introduction of MPS was capable of obvious increase in water repellency.

Liu, Bailing; Deng, Xiaobo; Cao, Shunsheng; Li, Songjun; Luo, Rong

2006-01-01

321

Real time small angle X-ray scattering from cyclically stretched nanoparticle-filled siloxane elastomers  

NASA Astrophysics Data System (ADS)

The origin of the cyclic softening and hysteresis (the well known "Mullins effect") observed in nanoparticle-filled elastomers is still debated. To probe this question we used synchrotron-based, time resolved, small angle x-ray scattering (SAXS) to observe changes in the structure of silica-filled siloxane elastomers with different filler loading and surface treatments under step cycle tensile deformation. We perform reverse Monte Carlo (RMC) simulations using graphical processing units (GPUs) to infer the real space configuration of the filler network that gives rise to the SAXS pattern and we compute the scattering invariant to quantify any void formation. We observe that the deformation is non-affine on length scales corresponding to the filler particles. The particles collect in "rafts" perpendicular to the tensile axis such that most of the deformation occurs in the elastomer-rich regions between rafts. At the largest deformations a scattering streak appears in a direction normal to the tensile axis at very small diffraction vectors (0.01 nm-1) which we attribute to the formation of elliptical voids whose long axis lies in the tensile direction.

Scholz, Arthur K.; Zhang, Huan; Chan, Elaine R.; Hexemer, Alexander; Kramer, Edward J.

2011-03-01

322

Novel gelatin siloxane nanoparticles decorated by Tat peptide as vectors for gene therapy  

NASA Astrophysics Data System (ADS)

In principle, the technique of gene delivery involves taking complete or parts of genes that can code specific messages and delivering them to selected cells in the body. Such a transfer of plasmid DNA into mammalian cells has posed major challenges for gene therapy. A series of gelatin-siloxane nanoparticles (GS NPs) with controlled size and surface charge were synthesized through a two-step sol-gel process. In order to increase the efficiency of cellular uptake, HIV-derived Tat peptide was further grafted to GS NPs. In vitro co-location and endocytosis inhibition experiments suggested that the as-synthesized TG NPs may enter HeLa cells via a combined pathway of lipid-raft- and receptor-dependent endocytosis, and only cause little cell damage. Moreover, this study shows the encapsulation of a plasmid DNA in TG NPs to be obtained as a non-viral gene vector. This kind of encapsulation provides complete protection to the plasmid DNA from the external DNase and serum environment, and generates the hope that the resulting formulation can be developed into a potential vector for effective gene delivery. In order to check this potential, the reporter gene pSV?-gal was encapsulated, and in vitro transfection efficiency of this system was found to be nearly 130% compared to the commercially available transfection reagent Lipofectamine™.

Wang, Zu-yong; Zhao, Yang; Ren, Lei; Jin, Li-hua; Sun, Li-ping; Yin, Pei; Zhang, Ya-fei; Zhang, Qi-Qing

2008-11-01

323

Poly(dimethyl siloxane) surface modification with biosurfactants isolated from probiotic strains.  

PubMed

Depending on the final application envisaged for a given biomaterial, many surfaces must be modified before use. The material performance in a biological environment is mainly mediated by its surface properties that can be improved using suitable modification methods. The aim of this work was to coat poly(dimethyl siloxane) (PDMS) surfaces with biosurfactants (BSs) and to evaluate how these compounds affect the PDMS surface properties. BSs isolated from four probiotic strains (Lactococcus lactis, Lactobacillus paracasei, Streptococcus thermophilus A, and Streptococcus thermophilus B) were used. Bare PDMS and PDMS coated with BSs were characterized by contact angle measurements, infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The influence of the surface modifications on the materials blood compatibility was studied through thrombosis and hemolysis assays. The cytotoxicity of these materials was tested against rat peritoneal macrophages. AFM results demonstrated the successful coating of the surfaces. Also, by contact angle measurements, an increase of the coated surfaces hydrophilicity was seen. Furthermore, XPS analysis indicated a decrease of the silicon content at the surface, and ATR-FTIR results showed the presence of BS characteristic groups as a consequence of the modification. All the studied materials revealed no toxicity and were found to be nonhemolytic. The proposed approach for the modification of PDMS surfaces was found to be effective and opens new possibilities for the application of these surfaces in the biomedical field. PMID:21681946

Pinto, S; Alves, P; Santos, A C; Matos, C M; Oliveiros, B; Gonçalves, S; Gudiña, E; Rodrigues, L R; Teixeira, J A; Gil, M H

2011-06-16

324

Poly (dimethyl siloxane) micro/nanostructure replication using proton beam written masters  

NASA Astrophysics Data System (ADS)

Proton beam writing (PBW) has been proven to be a powerful tool for fabricating micro and nanostructures with high aspect ratio. However, being a direct-write technique, and therefore, a serial process, PBW is not economic for low cost multiple component production. Techniques for replicating PBW structures with low cost are necessary for applications in for example nanofluidics, tissue engineering and optical devices. We have investigated casting poly (dimethyl siloxane) (PDMS Sylgard 184, Dow Corning Corp.) with PBW structures as masters. First, a 2 MeV focused H2+ beam was written into a 2 ?m thick PMMA layer spin coated onto 50 ?m thick Kapton film substrate. Next, these PMMA structures, with details down to 700 nm, were replicated with PDMS. Without any release coating treatment, PDMS circular pillars, 700 nm in diameter were successfully replicated. We also fabricated a nickel master with nanofeature dimensions and 2 ?m depth using proton beam writing and sulfamate electroplating. The nickel master was used to successfully replicate a prototype DNA separation chip using PDMS.

Shao, P. G.; van Kan, J. A.; Ansari, K.; Bettiol, A. A.; Watt, F.

2007-07-01

325

Calibration and application of a passive air sampler (XAD-PAS) for volatile methyl siloxanes.  

PubMed

Because the atmosphere is key to understanding the environmental behavior of volatile methyl siloxanes (VMS), a variety of reliable air sampling methods are needed. The purpose of this study was to calibrate and evaluate an existing, polystyrene-divinylbenzene copolymeric resin-based passive air sampler (XAD-PAS) for VMS. Sixteen XAD-PAS were deployed for 7-98 days at a suburban site in Toronto, Canada, while the VMS concentration in air was monitored by an active sampling method. This calibration and a subsequent field test further allowed for investigation of the temporal and spatial variability of VMS in the region. Uptake in the XAD-PAS of octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and three linear VMS was linear throughout the whole deployment period. Sampling rates were between 0.4 and 0.5 m(3)/day. The XAD-PAS measured ?VMS concentrations ranged from nondetects in rural areas (n = 3), to 169 ± 49 ng/m(3) in the urban region (n = 21), to levels above 600 ng/m(3) at sewage treatment plants (n = 2). Levels and composition of VMS within the urban area were remarkably uniform in space. Levels, but not composition, were highly variable in time and weakly correlated with temperature, wind speed, and wind direction. PMID:23527480

Krogseth, Ingjerd S; Zhang, Xianming; Lei, Ying D; Wania, Frank; Breivik, Knut

2013-04-08

326

Nanocomposites of ZnS and poly-(dimethyl)-block-(phenyl)siloxane as a new high-refractive-index polymer media  

NASA Astrophysics Data System (ADS)

In the present paper, we describe a new and original method to obtain transparent, siloxane-based composites, with high refractive index (up to 1.68). The method is based on the decomposition of Zn-siloxane, mixed with a poly-(dimethyl)-block-(phenyl)siloxane matrix in different ratios. It was found that after treatment of such mixed metal-containing polymer blend with H2S, the nanoparticles of ZnS are formed, with the size in a 1- to 5-nm range, which allow effective increase of the refractive index of the nanocomposite mixture with poly-(dimethyl)-block-(phenyl)siloxane without loss of film transparency. We succeded to increase the refractive index from 1.54 (pure matrix) up to 1.68 (composite with a ZnS content of 4.6 vol.%). The siloxane-based compositions are optically transparent, which makes it possible to use them as light-emitting diodes or solar cell sealants or adhesives.

Sergienko, Natalia; Godovsky, Dmitri; Zavin, Boris; Lee, Minjong; Ko, Minjin

2012-03-01

327

Self-assembling siloxane bilayer directly on SiO2 surface of micro-cantilevers for long-term highly repeatable sensing to trace explosives.  

PubMed

This paper presents a novel sensing layer modification technique for static micro-cantilever sensors that detect trace explosives by measuring specific adsorption-induced surface stress. For the first time, a method of directly modifying a siloxane sensing bilayer on an SiO(2) surface is proposed to replace the conventional self-assembled monolayers (SAMs) of thiols on Au to avoid the trouble from long-term unstable Au-S bonds. For modifying the long-term reliable sensing bilayer on the piezoresistor-integrated micro-cantilevers, a siloxane-head bottom layer is self-assembled directly on the SiO(2) cantilever surface, which is followed by grafting another explosive-sensing-group functionalized molecule layer on top of the siloxane layer. The siloxane-modified sensor has experimentally exhibited a highly resoluble response to 0.1 ppb TNT vapor. More importantly, the repeated detection results after 140 days show no obvious attenuation in sensing signal. Also observed experimentally, the specific adsorption of the siloxane sensing bilayer to TNT molecules causes a tensile surface stress on the cantilever. Herein the measured tensile surface stress is in contrast to the compressive surface stress normally measured from conventional cantilever sensors where the sensitive thiol-SAMs are modified on an Au surface. The reason for this newly observed phenomenon is discussed and preliminarily analyzed. PMID:20534897

Chen, Ying; Xu, Pengcheng; Li, Xinxin

2010-06-10

328

Self-assembling siloxane bilayer directly on SiO2 surface of micro-cantilevers for long-term highly repeatable sensing to trace explosives  

NASA Astrophysics Data System (ADS)

This paper presents a novel sensing layer modification technique for static micro-cantilever sensors that detect trace explosives by measuring specific adsorption-induced surface stress. For the first time, a method of directly modifying a siloxane sensing bilayer on an SiO2 surface is proposed to replace the conventional self-assembled monolayers (SAMs) of thiols on Au to avoid the trouble from long-term unstable Au-S bonds. For modifying the long-term reliable sensing bilayer on the piezoresistor-integrated micro-cantilevers, a siloxane-head bottom layer is self-assembled directly on the SiO2 cantilever surface, which is followed by grafting another explosive-sensing-group functionalized molecule layer on top of the siloxane layer. The siloxane-modified sensor has experimentally exhibited a highly resoluble response to 0.1 ppb TNT vapor. More importantly, the repeated detection results after 140 days show no obvious attenuation in sensing signal. Also observed experimentally, the specific adsorption of the siloxane sensing bilayer to TNT molecules causes a tensile surface stress on the cantilever. Herein the measured tensile surface stress is in contrast to the compressive surface stress normally measured from conventional cantilever sensors where the sensitive thiol-SAMs are modified on an Au surface. The reason for this newly observed phenomenon is discussed and preliminarily analyzed.

Chen, Ying; Xu, Pengcheng; Li, Xinxin

2010-07-01

329

DIELECTRIC PROPERTIES OF POLYVINYL ALCOHOL, POLY(METHYL METHACRYLATE), POLYVINYL BUTYRAL RESIN AND POLYIMIDE AT LOW TEMPERATURES  

SciTech Connect

Performance of materials and their compatibility determine the size of the electrical insulation in power equipment. For this reason dielectric properties of electrical insulation materials are needed for low temperature power applications. In this work we report the dielectric properties of four polymers: polyvinyl alcohol (PVA), poly(methyl methacrylate) (PMMA), polyvinyl butyral resin (PVB), and polyimide (PI--Kapton\\textregistered). The dielectric measurements are performed with an electrical impedance analyzer in the frequency domain. The impedances are recorded in a cryocooler in the temperature range from 45K to 350K. The dielectric breakdown characteristics of the polymers are measured in a liquid nitrogen bath at atmospheric pressure. It is observed that PI and \\pmma\\ dissolved in toluene have the lowest dielectric losses for temperatures lower than $100\\ \\kelvin$. \\Blx\\ and PI have the smallest spread in their breakdown strength data.

Tuncer, Enis [ORNL; Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL

2008-01-01

330

Dielectric Properties of Polyvinyl Alcohol, Poly(methyl Methacrylate), Polyvinyl Butyral Resin and Polyimide at Low Temperatures  

NASA Astrophysics Data System (ADS)

Performance of materials and their compatibility determine the size of the electrical insulation in power equipment. For this reason dielectric properties of electrical insulation materials are needed for low temperature power applications. In this work we report the dielectric properties of four polymers: polyvinyl alcohol (PVA), poly(methyl methacrylate) (PMMA), polyvinyl butyral resin (PVB), and polyimide (PI-Kapton®). The dielectric measurements are performed with an electrical impedance analyzer in the frequency domain. The impedances are recorded in a cryocooler in the temperature range from 45 K to 350 K. The dielectric breakdown characteristics of the polymers are measured in a liquid nitrogen bath at atmospheric pressure. It is observed that PI and PMMA dissolved in toluene have the lowest dielectric losses for temperatures lower than 100 K. PVB and PI have the smallest spread in their breakdown strength data.

Tuncer, Enis; Sauers, Isidor; James, D. Randy; Ellis, Alvin R.

2008-03-01

331

Ionic conductivity of polyelectrolyte derivatives of poly(vinyl alcohol)-lithium ion complex films  

Microsoft Academic Search

Ionic conductivity of various polymeric hybrid complexes made from the polyelectrolytes carboxymethylated poly(vinyl alcohol) (PVAC), poly(vinyl alcohol) acetalized with glyoxylic acid (PVAG) and poly(vinyl alcohol) acetalized with iodine N-methyl-4-pyridyladehyde (PVAP) were investigated. It was found that when the content of carboxyl group in PVAC reaches 5.3% and the content of carboxyl group in PVAG is more than 9.7%, the ion

Guan-Ling Bao; Wel-Qin Yun; Shl-Bi Fang; Ying-Yan Jiang

1987-01-01

332

Production of a calcium silicate cement material from alginate impression material.  

PubMed

The purpose of this study was to synthesize biomaterials from daily dental waste. Since alginate impression material contains silica and calcium salts, we aimed to synthesize calcium silicate cement from alginate impression material. Gypsum-based investment material was also investigated as control. X-ray diffraction analyses revealed that although firing the set gypsum-based and modified investment materials at 1,200°C produced calcium silicates, firing the set alginate impression material did not. However, we succeeded when firing the set blend of pre-fired set alginate impression material and gypsum at 1,200°C. SEM observations of the powder revealed that the featured porous structures of diatomite as an alginate impression material component appeared useful for synthesizing calcium silicates. Experimentally fabricated calcium silicate powder was successfully mixed with phosphoric acid solution and set by depositing the brushite. Therefore, we conclude that the production of calcium silicate cement material is possible from waste alginate impression material. PMID:22864217

Washizawa, Norimasa; Narusawa, Hideaki; Tamaki, Yukimichi; Miyazaki, Takashi

2012-01-01

333

Families of incest: a collation of clinical impressions.  

PubMed

The present paper provides a collation of the impressions of clinical workers regarding families in which father-daughter incest has incurred. Responses of the workers indicate that the incestuous relationship is typically not limited to one or two sexual encounters, but the relationship can become a stable part of family life. The sexual interactions appear to parallel sexual practices in non-incestuous relationships. Daughters involved in incest are viewed as submissive, passive, fearful, whereas the fathers are viewed as dominating, impulsive, and using violence or threats to obtain the daughters sexual co-operation. Mothers are viewed as weak and as failing to provide help for their daughters. The picture of the family in which father-daughter incest occurs is one in which unhappy people are unable to establish satisfying human relationships. PMID:7399828

Selby, J W; Calhoun, L G; Jones, J M; Matthews, L

1980-01-01

334

Neuro-impressions: interpreting the nature of human creativity  

PubMed Central

Understanding the creative process is essential for realizing human potential. Over the past four decades, the author has explored this subject through his brain-inspired drawings, paintings, symbolic sculptures, and experimental art installations that present myriad impressions of human creativity. These impressionistic artworks interpret rather than illustrate the complexities of the creative process. They draw insights from empirical studies that correlate how human beings create, learn, remember, innovate, and communicate. In addition to offering fresh aesthetic experiences, this metaphorical art raises fundamental questions concerning the deep connections between the brain and its creations. The author describes his artworks as embodiments of everyday observations about the neuropsychology of creativity, and its all-purpose applications for stimulating and accelerating innovation.

Siler, Todd Lael

2012-01-01

335

Effects of Exposure to Advertisements on Audience Impressions  

NASA Astrophysics Data System (ADS)

This study investigated effects of listening and/or watching commercial-messages (CMs) on audience impressions. We carried out experiments of TV advertisements presentation in conditions of audio only, video only, and audio-video. As results, we confirmed the following two effects: image-multiple effect, that is, the audience brings to mind various images that are not directly expressed in the content, and marking-up effect, that is, the audience concentrates on some images that are directly expressed in the content. The image-multiple effect, in particular, strongly appeared under the audio only condition. Next, we investigated changes in the following seven subjective responses; usage image, experience, familiarity, exclusiveness, feeling at home, affection, and willingness to buy, after exposure to advertisements under conditions of audio only and audio-video. As a result, noting that the image-multiple effect became stronger as the evaluation scores of the responses increased.

Hasegawa, Hiroshi; Sato, Mie; Kasuga, Masao; Nagao, Yoshihide; Shono, Toru; Norose, Yuka; Oku, Ritsuya; Nogami, Akira; Miyazawa, Yoshitaka

336

Impression Creep Behavior of a Cast AZ91 Magnesium Alloy  

NASA Astrophysics Data System (ADS)

The creep behavior of the cast AZ91 magnesium alloy was investigated by impression testing. The tests were carried out under constant punching stress in the range 100 to 650 MPa, corresponding to 0.007 ? ? imp/ G ? 0.044, at temperatures in the range 425 to 570 K. Assuming a power-law relationship between the impression velocity and stress, depending on the testing temperature, stress exponents of 4.2 to 6.0 were obtained. When the experimental creep rates were normalized to the grain size and effective diffusion coefficient, a stress exponent of approximately 5 was obtained, which is in complete agreement with stress exponents determined by the conventional creep testing of the same material reported in the literature. Calculation of the activation energy showed a slight decrease in the activation energy with increasing stress such that the creep-activation energy of 122.9 kJ/mol at ? imp/ G = 0.020 decreases to 94.0 kJ/mol at ? imp/ G = 0.040. Based on the obtained stress exponents and activation energy data, it is proposed that dislocation climb is the controlling creep mechanism. However, due to the decreasing trend of creep-activation energy with stress, it is suggested that two parallel mechanisms of lattice and pipe-diffusion-controlled dislocation climb are competing. To elucidate the contribution of each mechanism to the overall creep deformation, the creep rates were calculated based on the effective activation energy. This yielded a criterion that showed that, in the high-stress regimes, the experimental activation energies fall in the range in which the operative creep mechanism is dislocation climb controlled by dislocation pipe diffusion. In the low-stress regime, however, the lattice-diffusion dislocation climb is dominant.

Kabirian, F.; Mahmudi, R.

2009-01-01

337

How first impressions of a customer impact effectiveness in an initial sales encounter  

Microsoft Academic Search

First impressions of others affect both the content and outcomes of a variety of interpersonal encounters. In sales encounters,\\u000a a salesperson’s first impressions of a customer provide a starting point for probing customer needs and for adapting to those\\u000a needs. This implies that salesperson effectiveness in an initial sales encounter is associated— at least in part—with a salesperson’s\\u000a first impression

Kenneth R. Evans; Robert E. Kleine; Timothy D. Landry; Lawrence A. Crosby

2000-01-01

338

The effects of different storage conditions on polyether and polyvinylsiloxane impressions.  

PubMed

While being shipped to a laboratory, impressions can be exposed to excessive temperatures. This study compared the effects of different time and temperature storage conditions, including temperature extremes of 66 C and -10 C, on the accuracy of addition silicone and polyether impressions. The greatest distortion generally occurred as a result of the 66 C temperature extreme. The authors recommend that impressions be poured in stone according to manufacturers' specifications before being shipped to a dental laboratory. PMID:9685767

Purk, J H; Willes, M G; Tira, D E; Eick, J D; Hung, S H

1998-07-01

339

Controlling the variable of pressure in the production of test footwear impressions.  

PubMed

Footwear impression lifting and enhancement techniques may be affected by several variables introduced during the production of test footwear impressions, thus limiting the usefulness of enhancement technique comparisons and the results obtained. One such variable is the force applied when the impressed mark is being made. Producing consistent test impressions for research into footwear enhancement techniques would therefore be beneficial. This study was designed to control pressure in the production of test footwear impressions when mimicking a stamping action. Twenty-seven volunteers were asked to stamp on two different surfaces and the average stamping force was recorded. Information from the data obtained was used to design and build a mechanical device which could be calibrated to consistently deliver footwear impressions with the same force onto a receiving surface. Preliminary experiments using this device and different contaminants on the footwear sole have yielded consistent and repeatable impressions. Controlling the variable of pressure for the production of test impressions in this study demonstrated that the differences observed were visual (due to the amount of contaminant transferred and subsequent enhancement) and did not affect the replication of outer sole characteristics. This paper reports the development of the device and illustrates the quality of the impressions produced. PMID:22841140

Farrugia, Kevin J; Riches, Philip; Bandey, Helen; Savage, Kathleen; NicDaéid, Niamh

2011-12-22

340

Effects of Adaptation Gap on Users' Variation of Impression about Artificial Agents  

NASA Astrophysics Data System (ADS)

We describe an ``adaptation gap'' that indicates the differences between the functions of artificial agents users expect before starting their interactions and the functions they perceive after the interactions. We investigated the effects of this adaptation gap on users' impressions of the artificial agents because any variations in impressions before and after the start of an interaction determine whether the user feels that this agent is worth continuing an interaction. The results showed that the positive or negative signs of the adaptation gap and the subjective impression scores of the agents before the experiment affected the final users' impressions of the agents significantly.

Komatsu, Takanori; Yamada, Seiji

341

A novel technique of impression procedure in a hemimaxillectomy patient with microstomia.  

PubMed

A restricted mouth opening in hemimaxillectomy patient can create a significant problem with the insertion and the removal of the obturator prosthesis. Even it poses a problem in impression making due to small oral opening. A modification of the standard impression procedure is often necessary to accomplish an acceptable impression in the fabrication of a successful prosthesis. Sectional trays are a good option for such patients. This paper describes a novel technique of impression procedure and a method of fabricating a sectional tray with the anterior and the posterior locking mechanism for a hemimaxillectomy patient with limited oral opening. PMID:23316395

Deogade, Suryakant C

2012-12-18

342

Reliability of antagonistic arch impression in dental prostheses: clinical evaluation of different preimpression preparation procedures.  

PubMed

This study compared the influence of different methods of preimpression preparation on the quality of occlusal reproduction in irreversible hydrocolloid impressions. A total of 30 impressions of the lower dental arch of a patient were made with five different preimpression preparation procedures. Stone casts were made and analyzed. Critical comparison showed that the preimpression preparation influenced the quality of the occlusal surface of the cast. Fingerpainting the occlusal surface with fluid hydrocolloid before positioning the loaded impression tray, associated with use of a saliva ejector, reduced the incidence of macroscopic defects on the occlusal surface of the impressions. PMID:8537917

Scotti, R; Lugli, M; D'Elia, A

1995-08-01

343

Insular and hippocampal contributions to remembering people with an impression of bad personality.  

PubMed

Our impressions of other people are formed mainly from the two possible factors of facial attractiveness and trustworthiness. Previous studies have shown the importance of orbitofrontal-hippocampal interactions in the better remembering of attractive faces, and psychological data have indicated that faces giving an impression of untrustworthiness are remembered more accurately than those giving an impression of trustworthiness. However, the neural mechanisms of the latter effect are largely unknown. To investigate this issue, we investigated neural activities with event-related fMRI while the female participants rated their impressions of the personalities of men in terms of trustworthiness. After the rating, memory for faces was tested to identify successful encoding activity. As expected, faces that gave bad impressions were remembered better than those that gave neutral or good impressions. In fMRI data, right insular activity reflected an increasing function of bad impressions, and bilateral hippocampal activities predicted subsequent memory success. Additionally, correlation between these insular and hippocampal regions was significant only in the encoding of faces associated with a bad impression. Better memory for faces associated with an impression of bad personality could reflect greater interaction between the avoidance-related insular region and the encoding-related hippocampal region. PMID:22349799

Tsukiura, Takashi; Shigemune, Yayoi; Nouchi, Rui; Kambara, Toshimune; Kawashima, Ryuta

2012-02-20

344

Influence of Variations in Liquid-Crystalline Content upon the Self-Assembly Behavior of Siloxane-Based Block Copolymers  

SciTech Connect

A series of well-defined smectic side chain liquid-crystalline (LC) block copolymers with a low glass transition (Tg) siloxane block has been synthesized via anionic polymerization; these systems consist of a glassy polystyrene block and a unique low glass transition temperature LC block based on poly(vinylmethylsiloxane) to which six different LCs have been synthesized and attached. The synthesis techniques used provide systematic control over covalent LC side chain content, allowing for a range of morphologies to be obtained from a single block copolymer backbone during a one-step LC attachment reaction. Variations in the LC structure and content significantly affect the morphology of the LC mesophase, allowing the smectic-to-isotropic transition temperature to be tuned from room temperature up to 150 C. There are two key driving forces in the self-assembly behavior of these materials that are significantly affected by the LC content. The first is the segmental interaction parameter (?) between the blocks, which is a function of the amount of LC attached to the siloxane block. The attachment percent of the LCs to the siloxane block determines the packing density, which affects the stability of the LC mesophase and its interactions with the inter-material dividing surface. The self-assembled morphologies are characterized as a function of LC content and the mechanisms for the observed behavior are detailed. Additional insights into the interactions between the LC and block copolymer mesophases are gained by investigating the morphologies in response to mechanical deformation. The elastic modulus of this system can be tailored over several orders of magnitude by controlling the LC content, and the thermo-mechanical behavior is also highly dependent. The ability to precisely control the degree of LC functionalization enables the custom design and tailoring of material properties for specific applications such as electro-mechanical, damping, and mechano-optical devices.

Verploegen,E.; Zhang, T.; Murlo, N.; Hammond, P.

2008-01-01

345

Amperometric biosensors for glucose, lactate, and glycolate based on oxidases and redox-modified siloxane polymers  

SciTech Connect

Amperometric biosensors based on flavin-containing oxidases undergo several steps which produce a measurable current that is related to the concentration of substrate. In the initial step, the substrate converts the oxidized flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN) into the reduced form (FADH{sub 2} or FMNH{sub 2}). Because these cofactors are located well within the enzyme molecule, direct electron transfer to the surface of a conventional electrode does not occur to a measurable degree. A common method of facilitating this electron transfer is to introduce oxygen into the system because it is the natural acceptor for the oxidases; the oxygen is reduced by the FADH{sub 2} or FMNH{sub 2} to hydrogen peroxide, which can then be detected electrochemically. The major drawback to this approach is the fact that oxidation of hydrogen peroxide requires a large overpotential, thus making these sensors susceptible to interference from electroactive species. To lower the necessary applied potential, several non-physiological redox couples have been employed to shuttle electrons between the flavin moieties and the electrode. For example, sensors based on the ferrocene/ferricinium redox couple and on electrodes consisting of conducting salts such as TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane) have previously been reported. Electron relays have also been attached directly to the enzyme molecule to facilitate electron transfer. More recently, these studies have been extended to include systems where the mediating redox species are covalently attached to polymers such as poly(pyrrole), poly(vinylpyridine), and poly(siloxane). The present paper describes the development of amperometric biosensors based on flavin-containing enzymes and this latter family of polymeric mediators. 9 refs., 5 figs.

Hale, P.D.; Inagaki, Toru; Lee, Hung Sui; Skotheim, T.A.; Karan, Hiroko I.; Okamoto, Yoshi (Brookhaven National Lab., Upton, NY (USA); Medgar Evers Coll., Brooklyn, NY (USA). Div. of Natural Science and Mathematics; Polytechnic Univ., Brooklyn, NY (USA). Dept. of Chemistry)

1989-01-01

346

Proton imaging of siloxanes to map tissue oxygenation levels (PISTOL): a tool for quantitative tissue oximetry†  

PubMed Central

Hexamethyldisiloxane (HMDSO) has been identified as a sensitive proton NMR indicator of tissue oxygenation (pO2) based on spectroscopic spin-lattice relaxometry. A rapid MRI approach has now been designed, implemented, and tested. The technique, proton imaging of siloxanes to map tissue oxygenation levels (PISTOL), utilizes frequency-selective excitation of the HMDSO resonance and chemical-shift selective suppression of residual water signal to effectively eliminate water and fat signals and pulse-burst saturation recovery 1H echo planar imaging to map T1 of HMDSO and hence pO2. PISTOL was used here to obtain maps of pO2 in rat thigh muscle and Dunning prostate R3327 MAT-Lu tumor-implanted rats. Measurements were repeated to assess baseline stability and response to breathing of hyperoxic gas. Each pO2 map was obtained in 3½ min, facilitating dynamic measurements of response to oxygen intervention. Altering the inhaled gas to oxygen produced a significant increase in mean pO2 from 55 Torr to 238 Torr in thigh muscle and a smaller, but significant, increase in mean pO2 from 17 Torr to 78 Torr in MAT-Lu tumors. Thus, PISTOL enabled mapping of tissue pO2 at multiple locations and dynamic changes in pO2 in response to intervention. This new method offers a potentially valuable new tool to image pO2 in vivo for any healthy or diseased state by 1H MRI.

Kodibagkar, Vikram D.; Wang, Xianghui; Pacheco-Torres, Jesus; Gulaka, Praveen; Mason, Ralph P.

2011-01-01

347

Synthesis and Characterization of Organosoluble Polysiloxaneimides Derived from Siloxane-containing Aliphatic Dianhydride and Various Aromatic Diamines  

Microsoft Academic Search

A new siloxane-containing monomer, 5,51-exo-(1,1,3,3,5,5-hexamethyl-trisiloxane -1,5-diyl) bisbicyclo[2,2,1]heptene-2,3-endo-dicarboxylic anhydride (3) was synthesized by the hydrosilylation reaction of 1,1,3,3,5,5-hexamethyl-trisiloxane (1) and cis-5-norbornene-endo-2,3-dicarboxylic anhydride (2). A series of organosoluble polysiloxaneimides (PI 5a-e) was prepared from the dianhydride 3 and several aromatic diamines 4 by a one-step high-temperature polycondensation method and the structures were characterized by IR and NMR. The effects of the main

Shouming Wu; Teruaki Hayakawa; Masa-Aki Kakimoto

2008-01-01

348

The use of a scannable impression coping and digital impression technique to fabricate a customized anatomic abutment and zirconia restoration in the esthetic zone.  

PubMed

This report described the fabrication of a customized anatomic abutment and zirconia restoration in the esthetic zone with a digital pathway. The implant level impression was made with a scannable impression coping and intraoral digital scanner. The milled definitive polyurethane cast with corresponding implant analog, customized anatomic abutment, and definitive zirconia restoration were made with a computer-aided design and computer-aided manufacturing (CAD/CAM) process. PMID:23522368

Lin, Wei-Shao; Harris, Bryan T; Morton, Dean

2013-03-01

349

Catalytic dehydrochlorination of polyvinyl chloride in two-phase systems  

SciTech Connect

The catalytic activity of quaternary ammonium salts (QAS), whose cation and anion structures are different, and the mechanism of catalytic two-phase dehydrochlorination of polyvinyl chloride (PVC) are studied. Under phase-transfer conditions, dehydrochlorination of PVC is shown to proceed at the interface via an ionic mechanism in the presence of quaternary ammonium salts. The catalytic activity of QAS is governed by both the cation lipophilicity and the anion nature and increases as alcohols are introduced into the reaction mixture. The alcohol nature does not influence the extent of the reaction completion, but it does effect the supermolecular structure of the polyacetylene synthesized.

Leplyanin, G.V.; Salimgareeva, V.N.; Sannikova, N.S. [Institute of Organic Chemistry, Ufa (Russian Federation)

1994-11-01

350

Features of IR Holograms recorded on Polyvinyl alcohol films  

SciTech Connect

When holograms are recorded with continuous-wave radiation from a CO/sub 2/ laser in Plexiglas, a diffraction efficiency of about 20% may be attained. Results are presented on pulsed IR holograms recorded on films of polyvinyl alcohol. The holograms are recorded with a TEA CO/sub 2/ laser giving a pulse length of 3 musec. The diffraction-efficiency results are given for holographic gratings having a spatial frequency of 50 mm/sup -1/. The IR recording mechanism related to relief change is evidently characteristic of other polymeric recording media.

Durasov, V.M.; Chatei, A.V.; Rubanov, A.S.; Stashkevich, I.V.

1986-01-01

351

Nanodielectric system for cryogenic applications: Barium titanate filled polyvinyl alcohol  

SciTech Connect

In the current study the focus is on dielectric properties (as a function of frequency and temperature) of a polymeric composite system composed of polyvinyl alcohol and barium titanate nano powder. In the investigations, the temperature range is between 50-295 K, and the frequency range is between $20\\ \\hertz-1\\ \\mega\\hertz$. Polarization and conduction processes are investigated in the linear regime. Dielectric breakdown strengths of samples are also reported. The materials presented have potential to be implemented in cryogenic capacitor or field grading applications.

Tuncer, Enis [ORNL; Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Duckworth, Robert C [ORNL

2008-01-01

352

Computational studies of polyvinyl alcohol encapsulated tetrahedral cadmium sulphide cluster  

NASA Astrophysics Data System (ADS)

In the present work theoretical encapsulation of tetrahedral cluster of cadmium sulphide within polyvinyl alcohol (PVA) chains has been studied. Density of states, binding energy and optical properties are calculated using density functional theory (DFT) as implemented in SIESTA code with local density approximation (LDA) functionals. We observe that PVA chains strongly interact with [Cd4(SH)10]2- cluster through-OH groups and results in broadening of the band gap. Absorption spectrum of hybrid structure is also computed which is comparable to experimental results.

Bala, Vaneeta; Tripathi, S. K.; Kumar, Ranjan

2013-06-01

353

Electrical and Thermal Properties of Polyvinyl Acetal Based Nanocomposites  

SciTech Connect

A water chemistry procedure is used to synthesize titanium dioxide nanoparticles which can later be blended with a polymer to form a nanodielectric. The synthesized nanoparticles are dispersed in two grades of polyvinyl acetal (commercially available under the trade names BX-L and KS-10, manufactured by SEKISUI Chemicals). Nanocomposite materials were prepared with 15 and 33 wt% titanium dioxide. The variation of the glass transition temperature with increasing filler weight fraction is presented. The dielectric breakdown strengths of the nanodielectric samples are reported. The presented results can be employed to optimize the dielectric properties of the studied nanocomposites for potential use in cryogenic high voltage applications.

Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Tuncer, Enis [ORNL; Polyzos, Georgios [ORNL; Pace, Marshall O [ORNL

2009-10-01

354

Rhamnolipid production by Pseudomonas aeruginosa immobilised in polyvinyl alcohol beads.  

PubMed

A marine bacterium, Pseudomonas aeruginosa BYK-2 (KCTC 18012P), was immobilised by entrapment in 10% (w/v) polyvinyl alcohol beads and optimized for the continuous production of rhamnolipid. The relative activity of rhamnolipid production was maintained at 80 approximately 90% of the initial production during 15 cycles in a repeated batch culture. Continuous culture was performed in a 1.8 1 airlift bioreactor, yielding 0.1 g rhamnolipid h(-1) at a dilution rate of 0.0 18 h(-1), 25 degrees C, initial pH 7, and 0.5 vvm aeration rate with a 1.21 working volume. PMID:15005149

Jeong, Hye-Sung; Lim, Dong-Jung; Hwang, Sun-Hee; Ha, Soon-Duck; Kong, Jai-Yul

2004-01-01

355

Phonon transport in an initially twisted polyvinyl acetate nanofiber  

NASA Astrophysics Data System (ADS)

A reduction in phonon thermal conductivity enhances thermoelectric performance. One method to accomplish this is by applying mechanical stress to a nanostructure. We consider an initially twisted 20 nm polyvinyl acetate nanofiber undergoing torsion. Our analytical method uses the continuum approach of Mooney's model. Torsion modifies the phonon dispersion. Angles of twist between 45° and 70° reduce the averaged phonon group velocity and the phonon thermal conductivity but when these angles are increased further, this conductivity increases. This suggests a phonon engineering approach to tune the thermal conductivity of nanomaterials.

Liangruksa, Monrudee; Puri, Ishwar K.

2013-05-01

356

Analysis of Antibacterial Action of Polyvinyl Chloride Surface Modified with Gentian Violet  

Microsoft Academic Search

The effect of incorporation of gentian violet into medical-grade polyvinyl chloride was studied in this work. The antibacterial properties of the resulting blend were evaluated and the influence of the amount of gentian violet assessed. Dispersion of the gentian violet in the polyvinyl chloride following the blending of the two components was uniform as was demonstrated by the optical images,

M. Sowe; M. Polaskova; I. Kuritka; T. Sedlacek; M. Merchan

2009-01-01

357

Production and Properties of Polyvinyl Alcohol Spinning Solutions Containing Protease C and Polyhexamethylene Guanidine  

Microsoft Academic Search

Comparative studies of the production conditions and properties of polyvinyl alcohol spinning solutions containing the proteolytic enzyme protease C, the polycationic antimicrobial polyhexamethylene guanidine hydrochloride or polyhexamethylene guanidine phosphate, and in some cases sodium alginate, were conducted. It was found that addition of protease C, polyhexamethylene guanidine hydrochloride, polyhexamethylene guanidine phosphate, and alginate to a polyvinyl alcohol water-alcohol solution, used

E. Yu. Aleshina; T. N. Yudanova; I. F. Skokova

2001-01-01

358

In situ Self Cross-Linking of Polyvinyl Alcohol Battery Separators.  

National Technical Information Service (NTIS)

The method disclosed is used to produce a polyvinyl alcohol sheet material wherein the polyvinyl alcohol is substantially free of 1,2 diol units, and has an acetal self cross-linked structure wherein the acetal content is determined by the 1,2 diol conten...

W. H. Philipp L. C. Hsu D. W. Sheibley

1978-01-01

359

In Situ Self Cross-Linking of Polyvinyl Alcohol Battery Separators.  

National Technical Information Service (NTIS)

A battery separator was produced from a polyvinyl alcohol sheet structure which was subjected to an in situ, self crosslinking process by selective oxidation of the 1,2 diol units present in the polyvinyl alcohol sheet structure. The 1,2 diol units were c...

W. H. Philipp L. C. Hsu D. W. Sheibley

1979-01-01

360

Histologic Long-term Follow-up after Embolization with Polyvinyl Alcohol Particles  

Microsoft Academic Search

Summary: A large facial vascular malformation was embolized with polyvinyl alcohol particles twice in 8 years. Resected tissue enabled long-term examination of this material, confirming its chemical inertness and revealing minimal tissue reaction to it apart from calcification. No particle migration, fragmentation, or absorption occurred. There was some recanalization of occluded vessels. Most vessels containing polyvinyl alcohol particles, and all

George S. Davidson; Karel G. Terbrugge

361

Preparation of PVP immobilized microporous chlorinated polyvinyl chloride membranes on fabric and their hydraulic permeation behavior  

Microsoft Academic Search

Chlorinated polyvinyl chloride (CPVC)\\/polyvinyl pyrrolidone (PVP) membranes were prepared using the water vapor induced phase separation technique. The surface pore size of the membrane was dependent on the relative humidity (RH) and the PVP content. PVP was used as the pore-forming and wetting agent. However, as PVP could leach during the filtration process, the PVP was immobilized within the CPVC

Jong Seok Kang; Ki Yoen Kim; Young Moo Lee

2003-01-01

362

Microwave reflectivity measurement of silicon urea polyvinyl alcohol \\/ epoxy resin composites in X and Ku bands  

Microsoft Academic Search

In the paper presented here, a thermally stable epoxy resin modified urea - polyvinyl alcohol - silicon blends have been prepared by in situ polymerization technique. For this, the materials were modified with triethylene tetramine (hardener) to obtain highly cross-linked thermosetting resins. The authors have synthesized the polymer composites; silicon-urea-polyvinyl alcohol in three ratios in weight percentages with analytical reagent

M. Murugan; V. K. Kokate

2009-01-01

363

Impression Management and Leadership Emergence in Virtual Settings:The Role of Gender and Media  

Microsoft Academic Search

This paper describes a theoretical model that articulates how members of virtual teams engage in various impression management behaviors to influence their peers' assessment of them as leaders. Given that previous research has indicated that men and women engage in different impression management behaviors and that settings differ with respect to the degree of technological capabilities, our model includes these

JoAnne Yong-Kwan Lim

2008-01-01

364

Impression management and retrospective sense-making in corporate narratives : A social psychology perspective  

Microsoft Academic Search

Purpose – Prior accounting research views impression management predominantly though the lens of economics. Drawing on social psychology research, this paper seeks to provide a complementary perspective on corporate annual narrative reporting as characterised by conditions of “ex post accountability”. These give rise to impression management resulting from the managerial anticipation of the feedback effects of information and\\/or to managerial

Doris M. Merkl-Davies; Niamh M. Brennan; Stuart J. McLeay

2011-01-01

365

Measured effects of surface cloth impressions on polar backscatter and comparison with a reflection grating model  

Microsoft Academic Search

This paper focuses on the nature of a typical composite surface and its effects on scattering. Utilizing epoxy typical of that in composites and standard composite fabrication methods, a sample with release cloth impressions on its surface is produced. A simple model for the scattering from the surface impressions of this sample is constructed and then polar backscatter measurements are

Eric I. Madaras; Edwin F. Brush III; S. L. Bridal; Mark R. Holland; James G. Miller

1992-01-01

366

Use of footwear impressions in crime scene investigations assisted by computerised footwear collection system  

Microsoft Academic Search

Crime scene footwear classification systems can be utilized to look for possible suspects, to get models and brand names for crime scene impressions and to link crime scenes. In this work a computerised footwear classification system is presented. The classification coding of the system has been designed especially for partial footwear impressions which are the most typical in crime scenes.

Sirkka Mikkonen; Vesa Suominen; Pia Heinonen

1996-01-01

367

Getting at the truth or getting along: Accuracy versus impression-motivated heuristic and systematic processing  

Microsoft Academic Search

Two studies examined the heuristic and systematic processing of accuracy- versus impression-moti- vated individuals expecting a discussion with a partner believed to hold either a favorable or unfa- vorable opinion on the discussion issue. Given the goal of having a pleasant interaction, impression- motivated (versus accuracy-motivated) participants in both studies were particularly likely to ex- press attitudes that were evaluatively

Serena Chen; David Shechter; Shelly Chaiken

1996-01-01

368

When it comes round to marking assignments: how to impress and how to ‘distress’ lecturers …  

Microsoft Academic Search

What do lecturers look for when marking essays? What impresses them and what frustrates them? In this paper, we present the results of a survey which asked lecturers to address these questions. Thirty?two lecturers responded to an email survey in which they listed the problems they found most frustrating when marking essays and the factors which most impressed them. This

Pete Greasley; Andrea Cassidy

2010-01-01

369

A conceptual framework of impression management: new insights from psychology, sociology and critical perspectives  

Microsoft Academic Search

In this paper we develop a conceptual framework, based on the concepts of rationality and motivation, which uses theories and empirical research from psychology\\/behavioural finance, sociology and critical accounting to systematise, advance and challenge research on impression management. The paper focuses on research that departs from economic concepts of impression management as opportunistic managerial discretionary disclosure behaviour resulting in reporting

Doris M. Merkl-Davies; Niamh M. Brennan

2011-01-01

370

Exophtalmos and basilar impression. A contribution to differential diagnosis of endocrine orbitopathy  

Microsoft Academic Search

We report on a male patient with exophthalmos of unclear etiology, basilar impression, syringohydromyelia and type II Arnold-Chiari malformation. Two diseases involving the orbital region were to be considered in differential diagnostic terms: endocrine orbitopathy and osseous orbit dysplasia. The typical physical appearance associated with basilar impression as well as suppurative keratitis in Lagophthalmos was striking. Tetraspasticity with pareses, bulbar

George Kahaly; Wibke Müller-Forell; Barbara Tettenborn; Victor Mihaljevic; Jürgen Beyer

1988-01-01

371

Impression Management in the Ethical Self-Presentation of Offenders Undergoing Presentence Evaluation  

Microsoft Academic Search

Ethical choices were assessed for offenders instructed to produce favorable versus unfavorable impressions. Pronounced impression management effects were obtained for prosocial and antisocial responses, and high scores on a dimension of change defined by these variables were related to sociopathic features on the MMPI. Highly consistent trends did not emerge for avoidance responses, although a secondary dimension of change was

Terrill R. Holland; Robert J. Boik

1978-01-01

372

First Impressions Formed of Boys with Learning Disabilities and Attention Deficit Disorder  

Microsoft Academic Search

The present study examined the first impressions that are formed of boys with either learning disabilities (LD), attention deficit disorder (ADD), or both disorders, in an effort to understand better why they are so often unpopular with and rejected by their peers. The intent of the study was to remedy methodological problems of previous first-impression studies to determine whether devaluation

Laura Bickett; Richard Milich

1990-01-01

373

Shake My Hand: Making the Right First Impression in Business with Nonverbal Communications.  

ERIC Educational Resources Information Center

Describes a hand shaking exercise dealing with making a good first impression with nonverbal communication. Asks students to list the characteristics of a good first impression. Discusses how the instructor teaches the students how to shake hands well. Discusses a broader approach regarding learning nonverbal behavior. (SC)

Hiemstra, Kathleen M.

1999-01-01

374

Older and younger adults' first impressions from faces: similar in agreement but different in positivity.  

PubMed

People readily form first impressions from faces, with consensual judgments that have significant social consequences. Similar impressions are shown by children, young adults (YA), and people from diverse cultures. However, this is the first study to systematically investigate older adults' (OA) impressions. OA and YA showed similar levels of within-age agreement in their impressions of competence, health, hostility, and trustworthiness. Both groups also showed stronger within- than between-age agreement. Consistent with other evidence for age-related increases in positivity, OA showed more positive impressions of the health, hostility, and trustworthiness of faces. These effects tended to be strongest for the most negatively valenced faces, suggesting that they derive from OA lesser processing of negative cues rather than greater processing of positive cues. An own-age bias in impressions was limited to greater OA positivity in impressions of the hostility of older faces, but not younger ones. Although OA and YA differed in vision and executive function, only OA slower processing speed contributed to age differences in impression positivity. Positivity effects in OA have not been previously linked to processing speed, and research investigating possible explanations for this effect would be worthwhile. PMID:23276216

Zebrowitz, Leslie A; Franklin, Robert G; Hillman, Suzanne; Boc, Henry

2012-12-31

375

Teaching: First Impressions First, or Choosing Atmosphere over Method and Management  

ERIC Educational Resources Information Center

As a writer who teaches and a teacher who writes, this author offers creative ways of producing a positive first impression on the first day of school. The key is finding a way to surprise one's students and creating first impressions that somehow introduces the tone a teacher wants his or her class to have. The author has learned that if he can…

Levy, Aaron

2004-01-01

376

First Impressions of the Symbolic Meanings Connoted by Reception Area Design  

Microsoft Academic Search

A study was conducted in which 38 undergraduate students and 64 executives were shown photographs of eight dffferent companies' reception areas. Subjects responded to each photograph by completing 12 bipolar adjective scales indicating their impressions of these companies. Factor analyses of their responses revealed two dimensions underlying these judgments: consideration and control. ANOVAs revealed that subjects formed different impressions of

Suzyn Ornstein

1992-01-01

377

Verbal and Nonverbal Impression Management Tactics in Behavior Description and Situational Interviews  

Microsoft Academic Search

This study investigated how structured interview formats, instructions to convey favorable impressions, and applicants' individual differences influenced the use and effectiveness of verbal and nonverbal impression management (IM). Results from 190 people who were screened for a training program demonstrated that interview format affected the kind of tactics used, which in turn positively influenced interviewer evaluations. Behavior description interviews triggered

Helga Peeters; Filip Lievens

2006-01-01

378

Political Impression Management: How Metaphors, Sound Bites, Appearance Effectiveness, and Personality Traits Can Win Elections  

Microsoft Academic Search

This article introduces the concepts of political impression management and perception politics. It furthermore discusses results from empirical case studies by the authors using experiments and applying recent research models. Three main points of interest will be addressed: sound bites, the effects of appearance in politics, and personality profiles in the media. According to the view of political impression management,

Christ'l De Landtsheer; Philippe De Vries; Dieter Vertessen

2008-01-01

379

A video Clinical Global Impression (CGI) in obsessive compulsive disorder.  

PubMed

The Clinical Global Impression scale (CGI) is frequently used in clinical research because of its face validity and ease of use but data on its reliability are scarce. Our goal was to estimate the reliability of the scale and compare reliability between face-to-face and video scoring. We analyzed 50 different video interviews recorded during 5 visits of a crossover trial to study the effect of subthalamic nucleus stimulation. Six specialized clinicians rated the CGI using these videos, providing 300 different ratings. The intraclass correlation was lower at inclusion (0.30 [0.13-0.50]) than at later visits (0.68 [0.61-0.80]). Reliability was not influenced by the patients' stimulation status. The mean of at least two independent evaluations of the video is needed to achieve an ICC greater than 0.8. The video CGI is a valid clinical outcome measure suitable for clinical trials (ClinicalTrials.gov number, NCT00169377). PMID:20621362

Bourredjem, Abderrahmane; Pelissolo, Antoine; Rotge, Jean-Yves; Jaafari, Nematollah; Machefaux, Sebastien; Quentin, Solene; Bui, Eric; Bruno, Nicolas; Pochon, Jean-Baptiste; Polosan, Mircea; Baup, Nicolas; Papetti, François; Chéreau, Isabelle; Arbus, Christophe; Mallet, Luc; du Montcel, Sophie Tezenas

2011-02-12

380

First impressions of the nurse and nursing care.  

PubMed

Patients (N = 1,180), nurses (N = 918), and administrators (N = 332) in 22 acute care hospitals across the country were surveyed regarding their first impression of the professional image communicated by nurses' uniforms. The Nurse Image Scale, with pictures of the same nurse in nine different uniforms, was used as the data gathering tool. A comparison of the mean score of each uniform as rated by all respondents (N = 2,430) showed the white pant uniform with stethoscope was rated significantly higher than other uniforms. The white pant uniform with cap, dress with cap, pants suit, and dress with stethoscope scored closely in a second place grouping. The white dress uniform and street clothes with laboratory coat tied for third place. Colored designer scrubs and white pants with colored top scored lowest. Ratings of patients, nurses, and administrators were similar, although patients tended to rank some uniforms significantly differently than nurses and administrators. The nurse in the pant uniform with stethoscope was most preferred for care. Least preferred was the nurse in colored scrubs and street clothes with lab coat. These findings point to the need for nurses to be differentiated from auxiliary health care personnel and to project a professional image in a competitive health care environment. PMID:9212545

Mangum, S; Garrison, C; Lind, C; Hilton, H G

1997-06-01

381

Impression Creep Characteristics of a Cast Mg Alloy  

NASA Astrophysics Data System (ADS)

The creep behavior of the cast Mg-6Al-0.3Mn alloy (AM60) was investigated by impression testing under constant punching stress in the range 150 to 650 MPa and at temperatures in the range 423 to 523 K, corresponding to 0.458 < T/T m < 0.567. The creep behavior can be divided into two stress regimes, with a change from the low-stress regime to the high-stress regime occurring, depending on the testing temperature, around 0.021 < ( ?/ G) < 0.033. Based on the steady-state power-law creep relationship, the stress exponents of 4 to 6 and 8 to 12 were obtained at low and high stresses, respectively. When the experimental creep rates were normalized to the pipe diffusion coefficient, however, the stress exponents of about 5 and 10 were obtained for the low- and high-stress regimes, respectively. The low-stress regime activation energies of about 76 to 84 kJ mol-1, which are close to 80 kJ mol-1 for dislocation-pipe diffusion in the Mg, and stress exponents in the range 4 to 6 suggest that the operative creep mechanism is dislocation climb. This behavior is in contrast to the high-stress regime, in which the stress exponents of 8 to 12 and activation energies of about 134 to 165 kJ mol-1 are indicative of a power-law breakdown.

Kondori, B.; Mahmudi, R.

2009-08-01

382

The role of activity in visual impressions of causality.  

PubMed

Phenomenal causality is an illusion built on an incomplete perception. It is an illusion because we can have visual impressions of causality when no interaction between objects is actually taking place. It is an illusion built on an incomplete perception because causality as we understand it neglects some factors involved in objective descriptions of interactions between objects in terms of the laws of mechanics. So, why don't we perceive object interactions in accordance with the laws of mechanics? I first consider what kinds of things can and cannot be causes perceptually, arguing that active objects can be causes and non-moving objects cannot be. Then, I argue that causal understanding originates with what we have the most direct experience of, our own actions on objects, and extends out from this point of origin to other domains of causality by a form of schema matching the interpretation of stimulus input by matching to abstracted stored representations of experiences. Schema matching raises the possibility of many more kinds of phenomenal causality than have hitherto been considered, and I conclude by suggesting some possibilities. PMID:16919228

White, Peter A

2006-08-17

383

Capturing finger and palm impressions using a hand cream and thermochromatic paper.  

PubMed

An inkless set of finger and palm impressions has been obtained on thermochromatic paper by incorporating the protic solvent butylene glycol into a base hand cream mixture, which is rubbed into the hands for 30 sec before donation. This requires no washing of the hands before or after donation, removing many of the difficulties associated with inked impressions. In a random trial of 50 male and 50 female participants (mean age 41 years), 96 found the hand cream pleasant and easy to use and all produced identifiable finger and palm impressions. Following donation, participants continued to rub the hand cream into their hands. Impressions were visible immediately after donation and have not exhibited fading 2 years after being taken. 10% of participants produced impressions that captured third-level detail, the variation between participants being thought to be associated with the amount of pressure applied during donation. PMID:23865966

Bond, John W

2013-07-18

384

Preparation and application of low molecular weight poly(vinyl chloride). III mechanical properties of blended poly(vinyl chloride)  

SciTech Connect

The blending effect of poly(vinyl chloride) with relatively higher molecular weight (HMW-PVC) and relatively lower molecular weight (LMW-PVC) has been investigated by measuring various mechanical properties: melt properties, tensile strength, tensile modulus, and impact strength. The blended PVC has slightly improved melt properties in comparison with the HMW-PVC used. The tensile strength of the blended PVC is related to the weight-average polymerization degree (Pw) of LMW-PVC and the LMW-PVC content. At the LMW-PVC content of 20%, the tensile strength of blended PVC is a maximum: approximately 58 MPa.

Yamamoto, Kikuo; Maehala, Takashi; Mitani, Katsuo; Mizutani, Yukio (Tokuyama Soda Co., Ltd., Tokuyama-city (Japan))

1993-11-05

385

Cross-linked polyvinyl alcohol and method of making same  

SciTech Connect

A film-forming polyvinyl alcohol polymer is mixed with a polyaldehyde-polysaccharide cross-linking agent having at least two monosaccharide units and a plurality of aldehyde groups per molecule, preferably an average of at least one aldehyde group per monosaccharide units. The cross-linking agent, such as a polydialdehyde starch, is used in an amount of about 2.5 to 20% of the theoretical amount required to cross-link all of the available hydroxyl groups of the polyvinyl alcohol polymer. Reaction between the polymer and cross-linking agent is effected in aqueous acidic solution to produce the cross-linked polymer. The polymer product has low electrical resistivity and other properties rendering it suitable for making separators for alkaline batteries. In that event, the mixture of polymer and cross-linking agent is formed into a sheet or film or the like and the film is cut to size and otherwise fabricated into a configuration suitable for a particular end use. The crosslinking reaction is then carried out to produce the final product.

Hsu, L.; Philipp, W.H.; Sheibley, D.W.

1981-06-09

386

Synthesis and characterization of poly(silyl ether)s and modified poly(siloxane)s  

NASA Astrophysics Data System (ADS)

Activated dihydridocarbonyltris(triphenylphosphine)ruthenium ( Ru) catalyzes the dehydrogenative silylation condensation copolymerization of ortho-quinones with alpha,o-dihydrido-oligodimethylsiloxanes to give high molecular weight copoly(arylene-1,2-dioxy/oligodimethylsiloxanylene)s in good chemical yield. The hydrosilylation polymerization of aliphatic o-dimethylsilyloxy ketones is also catalyzed by activated Ru to yield unsymmetrical poly(silyl ether)s. Likewise, Ru catalyzes the copolymerization of alpha,o-diketones with alpha,o-dihydrido-oligodimethylsiloxanes to yield symmetrical poly(silyl ether)s. A mechanism of the copolymerizations is proposed, in which beta-hydride elimination is favored over reductive elimination in the reaction of the ortho-quinones. Chiral centers affect the NMR spectra of the poly(silyl ether)s produced by hydrosilylation. The photoluminescence properties of the polymers were studied along with those of model compounds. The decrease in Tgs with increase in siloxane chain length as well as fluorescence spectra is discussed. RuH2(CO)(PPh3)3 (Ru), activated with a stoichiometric amount of styrene, catalyzes the anti-Markovnikov addition of an ortho C-H bond of benzophenone across the C-C double bonds of alpha,o-bis(trimethylsilyloxy)copoly(dimethylsiloxane/vinylmethylsiloxane), alpha,o-bis(vinyldimethsilyloxy)poly(dimethylsiloxane)s, and 1,3-divinyltetramethyldisiloxane to yield alpha,o-bis(trimethylsilyloxy)copoly[dimethylsiloxane/2-(2 '-benzophenonyl)ethylmethylsiloxane]s, alpha,o-bis[2-(2 '-benzophenonyl)ethyldimethylsilyloxy]poly(dimethylsiloxane)s, and 1,3-bis[2-(2'-benzophenonyl)ethyl]tetramethyldisiloxane, respectively. While the Mw/Mn and Tgs of the modified polysiloxanes are similar to those of the precursor polymers, an increase in molecular weight is observed upon heating. 1,3-bis[2-(2 '-Benzophenonyl)ethyl]tetramethyldisiloxane, a model compound, was utilized to test a mechanism for the increase in molecular weight. A mechanism is proposed. Fluorinated and non-fluorinated 1,9-bis(epoxyalkyl)pentasiloxanes have been prepared by the Pt-catalyzed hydrosilylation reaction of vinylepoxides with 1,9-dihydridopentasiloxanes. The 1,9-dihydridopentasiloxanes were prepared by the triflic acid-catalyzed ring-opening of the corresponding cyclotrisiloxanes in the presence of 1,1,3,3-tetramethyldisiloxane. Insoluble cross-linked thin films have been prepared by the diaryliodonium salt photo-acid catalyzed ring-opening polymerization of the 1,9-bis(epoxyalkyl)pentasiloxanes. These materials may be useful as anti-corrosion/foul-release coatings for marine applications.

Mabry, Joseph Mark

387

Grafting of a reactive siloxane onto an alpha-olefin in the melt phase  

NASA Astrophysics Data System (ADS)

This dissertation presents the outcomes of a study undertaken to graft a reactive siloxane onto an alpha-olefin in the melt phase with the objective of conducting grafting and sequentially making a film of low coefficient of friction in a twin screw extruder. The areas of focus of the research were (1) design of experiments, (2) batch kinetic study, (3) twin screw extruder grafting and film making and (4) film property analysis. The primary materials of the study were a film grade homopolymer polyethylene, Equistar NA345-013, a vinylmethylsiloxane-dimethylsiloxane copolymer, Gelest VDT-731, and an ethyl 3,3-di-(t-amylperoxy)-butyrate, Elf Atochem Lupersol 533-M75. The batch mixer was a Haake rheomixRTM 400 modified to conduct reaction under a N2 blanket. Continuous reactive extrusion and sequential film making was done in a Leistritz 18mm x 40/1 L/D corotating and intermeshing twin screw extruder coupled with a flex lip die. Reaction samples were analyzed using FT-IR for degree of grafting and GPC to determine changes in molecular weight distribution as measures of degree of side reactions. The factors with main effects on degree of grafting were found to be mole percent vinyl functionality available for reaction, amount of initiator and mixing temperature. Among side reactions chain scission was found to be absent. The degree of cross-linking was mainly dependent on mole percent of free radical initiator and mixing temperature. Grafting was found to be a third order reaction with respect to vinylsiloxane concentration. Batch kinetic data were scaled up to continuous reactive extrusion in the twin screw extruder. Tracer experiments with TiO2 were used to estimate the average residence time and the extent of axial dispersion. An axial plug flow dispersion model was assumed to represent the nonideal flow of the grafting reaction in the twin screw extruder. The model was found to under predict the degree of grafting from 9% up to 25%. The coefficient of friction of the grafted film was found to be lower than the base polymer film by 50% to 60%. This increased to 65% to 75% when both sets of film samples were subjected to 50 kGy of electron beam irradiation.

Bekele, Solomon

1999-11-01

388

Cost of Impressed Current Cathodic Protection for Coastal Oregon Bridges  

SciTech Connect

The State of Oregon is using arc-sprayed zinc coatings for anodes in impressed current cathodic protection (ICCP) systems on reinforced concrete coastal bridges. The two lowest bids for four ICCP projects were averaged and converted to 1997 dollars. The total average cost for the ICCP projects was $51.63/ft2 ($555.51/m2) of protected concrete. The cathodic protection part of the ICCP projects average $14.08/ft2 ($151.47/m2), while zinc anode installation cost an average of $7.13/ft2 ($76.67/m2). Oregon's rugged and beautiful coastline is graced with a series of historical arched bridges designed by Conde B. McCullough. McCullough is the internationally recognized architect who designed many of the Oregon Coast Highway (U.S. 101) bridges in the 1920s and 1930s. Many are listed on the National Historic Register. After the expense ($45m) and public outcry associated with the replacement of the historic Alsea Bay Bridge in Waldport, Oregon, the Oregon Department of Transportation began using impressed current cathodic protection (ICCP) to extend the service life of reinforced concrete bridges. Figure 1 visually illustrates the need for such remediation. It shows exposed rebar from underneath the Brush Creek Bridge, which is very representative of the conditions found underneath many coastal Oregon bridges. Four ICCP projects have been funded, put out for bid, and completed. The four projects, their bid closing dates, and their completion dates are the Cape Creek Bridge (1990- 1992), the Yaquina Bay Bridge south arches (1991-1995), the Depoe Bay Bridge (1993-1997), and the Yaquina Bay Bridge south approach (1995-1997). The Cape Creek, Yaquina Bay, and Depoe Bay Bridges are shown in Figs. 2-4. Other ICCP projects are underway on the Oregon coast. In the ICCP systems, arc-sprayed zinc coatings on the concrete surface are anodes that protect the steel rebar. Accelerated laboratory studies at the Albany Research Center have predicted zinc anode service lives of approximately 27 years based on long-term bond strength measurements.1-3 Experience in California4 has documented zinc anode service lives of over 11 years. Both indicate a substantial savings in project costs compared to bridge replacement. For example, the replacement cost of the arc-sprayed sections of the three Oregon bridges is estimated to be $57m, while the four ICCP projects on those bridges have cost $20m. (The $45m to replace the Alsea Bay Bridge was more than simply the replacement cost--it included expanding the bridge to four lanes and making the bridge ''ICCP ready'' by ensuring electrically continuous rebar).

Holcomb, Gordon R.; Cryer, Curtis B.

1998-07-01

389

The First Impression of Data Sent by Two Martian Rovers  

NASA Astrophysics Data System (ADS)

``Spirit'' at the Gusev crater near the dichotomy boundary sent a panoramic view, an image of the near ground and a very close view of a small spot analyzed by X-ray. The first impression of chaotic disposition of big and small rocks and sandy fragments is wrong. All scales images display striations in 4 directions probably due to intersecting undulations, besides, rock fragments are rather evenly distributed. This is not of surprise because many MOLA images show very regular patterns described earlier for intersecting wave processes on planetary surfaces [1]. The middle scale image shows angular rock fragments of various sizes protruding soil. There is an impression that the protruding blocks represent uplifted parts of a wave-woven surface of volcanic infilling , subsided parts being covered with sandy soil mainly of eolian origin. Such an interpretation is supported by the THEMIS image (released 23 Sept., 2003 in Internet) of a 22 km-diameter crater on Sirenum Fossae where wave structurized (volcanic?) material is gradually covered by eolian sediments leaving protruding high standing blocks (antinodes). The soil X-ray analysis shows high Si an Fe, some Al, Ca, Mg, K, Na, Cl, S, minor Cu, Ni, Zn that should be expected for a mixed material at low/highland contact contaminated by an eolian stuff. ``Opportunity'' is the first highland landing and in this is its highest importance. It seems that long awaited light (in color and density) rock type without Fe [2, 3 & others] is in front of us. The leveled out white outcrops probably represent this kind of rocks (albitites, syenites). Eleveted K, Na, CL, S, Si and H20 (!) detected by gamma and neutron spectra can be explained by sodalite (hydrosodalite) and cancrinite group minerals present in nepheline syenites -- albitites and always accompanied by zeolites containing water. The high chemical dichotomy (and mantle fractionation) between lowlands and highlands is an important part of the wave planetology (Theorem 4 [3]). References: [1] Kochemasov G.G. (1991) Periodic system of multi-ring planetary structures as result of interference of variously oriented lithospheric waves // Astronom. Tsirkular RAS, # 1550, 35-36 (in Russian); [2] Kochemasov G.G. (1995) Possibility of highly contrasting rock types at martian highland/lowland contact // In: Golombek M.P., Edgett K.S., and Rice J.W.Jr., eds. Mars Pathfinder Landing Site Workshop II: Characteristics of the Ares Vallis Region and Field Trips to the Channeled Scabland, Washington. LPI Tech. Rpt. 95-01, Pt. 1, LPI, Houston, 63 pp.; [3] Kochemasov G.G. (1999) On a successful prediction of martian crust fractionation based on comparative wave planetology // The Fifth International Conference on Mars, July 18-23, 1999, Pasadena, California, Abstr. # 6034, (CD-ROM).

Kochemasov, G. G.

390

Testicular cytology of alpaca: comparison between impressed and smeared slides.  

PubMed

Testicular fine needle aspiration (TFNA) has proven to be a simple and minimally invasive procedure, which allows assessments of cytological parameters of seminiferous epithelium/tubules more accurately in a short time. Though this technique does not cause negative effects on sperm quality or any damage to testicular tissue, its use is very limited in male animal infertility diagnostics. Report on the use of this technique in South American Camelids (SAC) is very limited. Therefore, the aim of this study was to evaluate the efficacy of TFNA for identification of different testicular cells and cell indices, and their correlation with that of impression cytology. A total of 98 slides were prepared from testes of six adult alpaca males, collected immediately after slaughter. Aspiration samples were performed by inserting a fine butterfly needle (21 G) connected to a 50 ml syringe into a testicle and multiple plane aspirations were carried out to obtain the materials destined to the smear. Three different imprints on slides were taken from each testicle. All slides were air-dried, stained with modified May--Grünwald--Giemsa (MGG) stain and then examined under light microscope with 1000× magnifications. Spermatogenic cells such as, spermatogonia (Sg), primary spermatocytes, secondary spermatocytes, early spermatids (ab), late spermatids (cd) and spermatozoa, and Sertoli cells were counted. The spermatozoa percentage was expressed as spermatic index (SI) and the number of Sertoli cells, counted apart, was expressed as sertoli cell index (SEI). There was not any significant difference between the spermatogenic cell parameters obtained from the two types of slides, but SEI were significantly different in two types of smears. The results of the study provide support for the use of TFNA as a useful minimally invasive modality to identify different spermatogenetic cell classes in alpaca. Moreover, the possibility to standardize this method might provide a greater impulse to the clinical diagnostics of SAC male infertility. PMID:21493020

Stelletta, C; Juyena, N S; Ponce Salazar, D; Ruiz, J; Gutierrez, G

2011-03-23

391

Evaluation of properties of irreversible hydrocolloid impression materials mixed with disinfectant liquids  

PubMed Central

Background: Addition of disinfectant to irreversible hydrocolloid impression materials can eliminate the disinfection step to avoid dimensional changes associated with it. The aim of the present study was to evaluate the effect of various disinfectant mixing liquids on the properties of commercially available irreversible hydrocolloid impression materials. Materials and Methods: Four commercially available irreversible hydrocolloid impression materials (Zelgan, Vignette, Tropicalgin, and Algitex) were mixed with disinfectant liquid containing chlorhexidine (0.1 and 0.2%) and sodium hypochlorite (0.1 and 0.5%). After mixing with disinfectant liquids, materials were evaluated for pH changes during gelation, gelation time, flow, gel strength, permanent deformation and detail reproduction. Results: Significant changes in gelation time were observed in irreversible hydrocolloid impression materials upon mixing with disinfectant liquids. In general, chlorhexidine increased the gelation time, whereas sodium hypochlorite reduced it. However, no significant changes in the flow were observed both with chlorhexidine and sodium hypochlorite. Gel strength was found to decrease when mixed with chlorhexidine, whereas an increase in gel strength was observed upon mixing with sodium hypochlorite. Permanent deformation of the most irreversible hydrocolloid impression materials was below the specification limit even after mixing with disinfectant liquids. Sodium hypochlorite significantly reduced the surface detail reproduction, whereas no change in detail reproduction was observed with chlorhexidine. Conclusion: Chlorhexidine solution can be used to mix irreversible hydrocolloid impression materials in regular dental practice as it did not significantly alter the properties. This may ensure effective disinfection of impressions.

Amalan, Arul; Ginjupalli, Kishore; Upadhya, Nagaraja

2013-01-01

392

Three-dimensional accuracy of implant and abutment level impression techniques: effect on marginal discrepancy.  

PubMed

Impression techniques should precisely represent the 3-dimensional status of implants to allow for the fabrication of passively fitting prostheses and subsequently the elimination of strain on supporting implant components and surrounding bone. The aim of this study was to compare the accuracy of an abutment level impression method with that of an implant level (direct and indirect) impression method using polyether impression material to obtain precise definitive casts and prostheses. A reference acrylic resin dentoform with 2 internal connection implants (Implantium) was made. A total of 21 medium-consistency polyether impressions of the dentoform, including 7 direct implant level, 7 indirect implant level, and 7 abutment level (after 2 straight abutments were secured), were made. Impressions were poured with American Dental Association (ADA) type IV stone, and the positional accuracy of the implant replica heads and abutment analogs in each dimension of x-, y-, and z-axes, as well as angular displacement (??), was evaluated using a coordinate measuring machine. Noble alloy 3-unit castings were fabricated and seated on the abutments in 3 groups; marginal discrepancies were measured at 4 points between prostheses and abutments. Data were analyzed using Mann-Whitney U test, 1-way analysis of variance (ANOVA), and Kruskal-Wallis tests. In comparisons of different impression techniques, only significant statistical ?? differences were noted between the abutment level method and other techniques (P < .001). Results of this study reveal that although the implant level impression method could better transfer the angular position of the implants (??), the impression method could not affect ?y, ?x, and ?z coordinates of the implants or marginal discrepancy of the 3-unit fixed partial dentures (FPD). PMID:20594060

Alikhasi, Marzieh; Siadat, Hakimeh; Monzavi, Abbas; Momen-Heravi, Fatemeh

2010-06-16

393

Impression techniques and misfit-induced strains on implant-supported superstructures: an in vitro study.  

PubMed

The purpose of this study was to compare misfit-induced strains on implant-supported superstructures fabricated by two impression techniques and two different elastomeric impression materials. A master cast hosting four Straumann implants was constructed. On this cast, a total of 21 implant-level impressions were made by the direct technique using a polyether impression material and synOcta screwed aluminum impression caps (PE-D), and by the indirect technique using polyether (PE-IN) or polyvinylsiloxane impression material (VPS-IN) with snap-on impression caps and synOcta plastic positioning cylinders. Two casts were randomly selected from each group of seven, and a total of four screw-retained superstructures, supported by either two or four implants (one of each type on both casts), were cast in a gold alloy for each group. Linear strain gauges were bonded on the superstructures, and misfit-induced strains were recorded during superstructure connection on each of the working casts and on the master cast using a data acquisition system and corresponding software at a sample rate of 10 kHz. Connection on the implants in the master cast increased strains considerably on most of the superstructures, in comparison with strain gradients measured when the superstructures were connected on the casts from which they were fabricated (P <.05). The differences in strain amplitude between connection on the cast from which the superstructure was fabricated and on the master cast were higher for superstructures fabricated by PE-D than for those fabricated by PE-IN and VPS-IN. The snap-on indirect impression technique for Straumann implants leads to acceptable superstructures, regardless of the impression material used. PMID:16939020

Cehreli, Murat C; Akça, Kivanç

2006-08-01

394

Basilar impression complicating osteogenesis imperfecta type IV: the clinical and neuroradiological findings in four cases  

PubMed Central

OBJECTIVES—To describe the clinical and neuroradiological features of basilar impression in patients with osteogenesis imperfecta type IV.?METHODS—Four patients with basilar impression were ascertained in a population study of osteogenesis imperfecta. All four had detailed clinical and neuroradiological examination with both CT and MRI of the craniocervical junction andposterior fossa structures.?RESULTS—All four showed significant compression of the posterior fossa structures and surgical decompression was performed with relief of symptoms.?CONCLUSION—Symptoms of cough headache and trigeminal neuralgia occurring in patients with osteogenesis imperfecta are indications for detailed clinical and neuroradiological investigation to document basilar impression.??

Hayes, M; Parker, G; Ell, J; Sillence, D

1999-01-01

395

The elastomers for complete denture impression: A review of the literature  

PubMed Central

This article reviews the current trends in materials used for complete denture impression. Peer-reviewed articles, published in English and in French between 1954 and 2007, were identified through a MEDLINE search (Pubmed and Elsevier) and a hand search of relevant textbooks and annual publications. Emphasis was made on the characteristics of the elastomers, their manipulation, the different techniques used, and the quality of the impression obtained. The combination of excellent physical properties, handling characteristics, and unlimited dimensional stability assures the popularity of these impression materials.

Daou, Elie E.

2010-01-01

396

[Determination of organotin compounds in polyvinyl chloride toys].  

PubMed

Organotin compounds in polyvinyl chloride toys were determined by GC/MS after ethyl derivatization with sodium tetraethylborate. The samples were 12 balls, 12 soft toys, 10 food toys and 13 face masks for children. Monooctyltin, dioctyltin and trioctyltin compounds were found in all face masks at the levels of 74.8-917 micrograms/g. 474-3,960 micrograms/g and 1.0-213 micrograms/g, respectively. They also were detected in 6 balls, 4 soft toys and 1 food toy. Monomethyltin and dimethyltin compounds were found in 8 face masks at the levels of 40.9-227 micrograms/g and 222-1,450 micrograms/g, respectively. Monobutyltin and dibutyltin (DBT) compounds were found in 1 ball, 3 food toys and 5 face masks. In particular, 1 ball and 4 face masks contained toxic DBT at the levels of 527-999 micrograms/g. PMID:14606431

Ohno, Hiroyuki; Suzuki, Masako; Aoyama, Taiki; Mitani, Kazunori

2003-08-01

397

Friction loss in straight pipes of unplasticized polyvinyl chloride.  

PubMed

In order to design proper ductwork for a local exhaust system, airflow characteristics were investigated in straight pipes of unplasticized polyvinyl chloride (PVC). A linear decrease in static pressure was observed downstream at points from the opening of the VU pipes (JIS K 6741) located at distances greater than 10 times the pipe diameter, for velocities ranging between 10.18-36.91 m/s. Roughness inside pipes with small diameters was found to be 0.0042-0.0056 mm and the friction factor was calculated on the basis of Colebrook's equation for an airflow transition zone. An extended friction chart was then constructed on the basis of the roughness value and the friction factor. This chart can be applied when designing a local exhaust system with the ducts of diameters ranging from 40 to 900 mm. The friction loss of the PVC pipe was found to be approximately 2/3 of that of a galvanized steel pipe. PMID:8768669

Iwasaki, T; Ojima, J

1996-01-01

398

Vitrification of Polyvinyl Chloride Waste from Korean Nuclear Power Plants  

SciTech Connect

Vitrification is considered as an economical and safe treatment technology for low-level radioactive waste (LLW) generated from nuclear power plants (NPPs). Korea is in the process of preparing for its first ever vitrification plant to handle LLW from its NPPs. Polyvinyl chloride (PVC) has the largest volume of dry active wastes and is the main waste stream to treat. Glass formulation development for PVC waste is the focus of study. The minimum additive waste stabilization approach has been utilized in vitrification. It was found that glasses can incorporate a high content of PVC ash (up to 50 wt%), which results in a large volume reduction. A glass frit, KEP-A, was developed to vitrify PVC waste after the optimization of waste loading, melt viscosity, melting temperature, and chemical durability. The KEP-A could satisfactorily vitrify PVC with a waste loading of 30 to 50 wt%. The PVC-frit was tolerant of variations in waste composition.

Sheng, Jiawei [Kyoto University (Japan); Choi, Kwansik [Nuclear Environment Technology Institute (Korea, Republic of); Yang, Kyung-Hwa [Nuclear Environment Technology Institute (Korea, Republic of); Lee, Myung-Chan [Nuclear Environment Technology Institute (Korea, Republic of); Song, Myung-Jae [Nuclear Environment Technology Institute (Korea, Republic of)

2000-02-15

399

Alignment layers with variable anchoring strengths from Polyvinyl Alcohol  

NASA Astrophysics Data System (ADS)

In the study of polyvinyl alcohol (PVA) alignment layers for liquid crystal devices, we found that the anchoring strength can be greatly varied by changing the alignment film thickness. Both the polar and azimuthal anchoring strengths increased with increasing film thickness; however, they had different film thickness dependences. It was also noticed that the quartic term in the expansion of the Rapini-Papoular anchoring energy was important for describing the polar anchoring. In the experiment, solid PVA was dissolved in a thinner and spin-coated on glass substrates to create alignment layers. The substrates were assembled to make electrically-controlled birefringence liquid crystal cells. The polar anchoring strength of the alignment layer was measured using the high field method and the azimuthal anchoring strength using the twist angle method.

Cui, Yue; Zola, Rafael S.; Yang, Young-Cheol; Yang, Deng-Ke

2012-03-01

400

Cross-linked polyvinyl alcohol films as alkaline battery separators  

SciTech Connect

Cross-linking methods were investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: (1) PVA-dialdehyde blends post-treated with an acid or acid periodate solution (two-step method) and (2) PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality (one-step method). Laboratory samples of each cross-linked type of film were prepared and evaluated in standard separator screening tests. The pilot-plant batches of films were prepared and compared to measure differences due to the cross-linking method. The pilot-plant materials were then tested in nickel oxide - zinc cells to compare the two methods with respect to performance characteristics and cycle life. Cell test results are compared with those from tests with Celgard.

Sheibley, D.W.; Manzo, M.A.; Gonzalez-Sanabria, O.D.

1982-03-01

401

Cross-linked polyvinyl alcohol films as alkaline battery separators  

SciTech Connect

Cross-linking methods have been investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: PVA-dialdehyde blends post-treated with an acid or acid periodate solution and PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality. Laboratory samples of each cross-linked type of film were prepared and evaluated in standard separator screening tests. Then pilotplant batches of films were prepared and compared to measure differences due to the cross-linking method. The pilot-plant materials were then tested in nickel oxide-zinc cells to compare the two methods with respect to performance characteristics and cycle life. Cell test results are compared with those from tests with Celgard.

Sheibley, D.W.; Gonzalez-Sanabria, O.D.; Manzo, M.A.

1983-02-01

402

Polyvinyl alcohol coating of polystyrene inertial confinement fusion targets  

SciTech Connect

An inertial confinement fusion (ICF) target made of polystyrene is first levitated in an acoustic field. The surface of the target is then etched using an appropriate solution (e.g., cyclohexane) to enhance the wetting characteristics. A specially prepared polyvinyl alcohol solution is atomized using an acoustic atomizer and deposited on the surface of the target. The solution is air dried to form a thin coating (2 ..mu..m) on the target (outside diameter approx.350--850 ..mu..m). Thicker coatings are obtained by repeated applications of the coating solution. Preliminary results indicate that uniform coatings may be achievable on the targets with a background surface smoothness in the order of 1000 A.

Annamalai, P.; Lee, M.C.; Crawley, R.L.; Downs, R.L.

1985-05-01

403

[Applications of polyvinyl alcohol in modern preparations of TCM].  

PubMed

As a drug additive, polyvinyl alcohol(PVA) has merits of solubility, easy forming, strong conglutination, high thermal stability, low toxicity and no irritation. In these years, PVA has been applied wider and wider in medicine industry. In the study of modem preparations of TCM PVA, as film material of membrane and pellicles, is very promising owing to its easy forming and excellent toughness. PVA is good polymer matrix for suppositories and gel, because it can not only carry drug but also improve the properties of preparations on application and technology. It can be said that PVA is an excellent carrier. At the present, PVA is mainly applied in vitro preparations of TCM, but its applications will be spread with further research. The prospective applications of PVA in osmotic pump controlled release preparations, drug carried microspheres and swelling controlled release system are foreseen. PMID:15719670

Zhang, Yun-hui; Li, Ning; Xu, Jian-chen; Xiao, Li

2004-02-01

404

Estimation of mechanochemical dechlorination rate of poly(vinyl chlorde).  

PubMed

Poly(vinyl chloride) (PVC) was ground in air with CaO in the presence of quartz powder as a grinding aid by a small-scale planetary ball mill to investigate the relation of the dechlorination rate of PVC with the impact energy of the balls calculated from a computer simulation based on the Discrete Element Method under various conditions. Mechanochemical dechlorination proceeds as the grinding progresses and is improved with an increase in both the mill speed and the amount of balls introduced into the mill. The same trend can be seen in the relation between the specific normal impact energy of the balls and the rotational speed. The relationship between the observed dechlorination rate and the computed normal impact energy of the balls is linear, with a correlation coefficient of 0.965. This relationship can be used to estimate the dechlorination rate of PVC in a large-scale planetary ball mill. PMID:11944691

Mio, Hiroshi; Saeki, Shu; Kano, Junya; Saito, Fumio

2002-03-15

405

Dancing on coke: smuggling cocaine dispersed in polyvinyl alcohol.  

PubMed

Recent trends suggest that cocaine smugglers have become more and more inventive to avoid seizures of large amounts of cocaine transported between countries. We report a case of a mail parcel containing a dance pad which was seized at the Customs Department of Brussels Airport, Belgium. After investigation, the inside of the dance pad was found to contain a thick polymer, which tested positive for cocaine. Analysis was performed using a routine colorimetric swipe test, gas chromatography coupled with mass spectrometry and nuclear magnetic resonance spectroscopy. The polymer was identified as polyvinyl alcohol (PVA) and contained 18% cocaine, corresponding to a street value of € 20,000. Laboratory experiments showed that cocaine could be easily extracted from the PVA matrix. This case report reveals a new smuggling technique for the transportation of large amounts of cocaine from one country to another. PMID:22040352

van Nuijs, Alexander L N; Maudens, Kristof E; Lambert, Willy E; Van Calenbergh, Serge; Risseeuw, Martijn D P; Van hee, Paul; Covaci, Adrian; Neels, Hugo

2011-10-31

406

Polyvinyl chloride meat-wrapping film study. Final report  

SciTech Connect

As a result of worker complaints in the Baltimore, Maryland area, potential health hazards associated with the use of polyvinyl-chloride film for wrapping meat were reviewed. Fumes generated during the meat-wrapping process were causing concern among the workers as they experienced respiratory irritation and distress. It appeared that only some of the meat wrappers experienced difficulty, only some of the rolls of film-produced irritations in the affected workers, and affected workers had prior histories of respiratory difficulties. Fumes were generated during hot-wire film cutting. The amount of fume generated depended significantly on the care taken during the operation. If the dispensing machines were improperly adjusted, large amounts of fumes could be obtained during the cutting process. The author concludes that the amounts of these chemicals released during this operation does not constitute a health hazard to the employees. It may be necessary, however, to remove persons with prior respiratory irritation from this particular job location.

Vandervort, R.

1988-01-01

407

Spectroscopic manifestations of flavomononucleotide dimers in polyvinyl alcohol films.  

PubMed

Absorption and fluorescence spectra of flavomononucleotide (FMN) in polyvinyl alcohol films (PVA) over a very wide concentration range are investigated. The dimerization constant as well as the pure monomer and dimer spectra are calculated and the structural parameters of FMN dimer are established. Excitation wavelength and temperature dependencies of FMN/PVA fluorescence spectra for different FMN concentrations were carried out. These measurements together with those of absorption reveal that dimers are imperfect traps for excitation energy and that the energy transfer can occur both in forward and in reverse direction. Moreover, it was shown that the observed temperature changes in fluorescence spectra may be qualitatively explained by the effect of inhomogeneous broadening of FMN energy levels and by the presence of fluorescent dimers. PMID:9659386

Grajek, H; Zurkowska, G; Bojarski, P; Kukli?ski, B; Smyk, B; Drabent, R; Bojarski, C

1998-05-19

408

Methodological Insights: Impression management: Developing and illustrating a scheme of analysis for narrative disclosures – a methodological note  

Microsoft Academic Search

Purpose – This paper aims to develop a holistic measure for analysing impression management and for detecting bias introduced into corporate narratives as a result of impression management. Design\\/methodology\\/approach – Prior research on the seven impression management methods in the literature is summarised. Four of the less-researched methods are described in detail, and are illustrated with examples from UK annual

Niamh M. Brennan; Encarna Guillamon-Saorin; Aileen Pierce

2009-01-01

409

Growth characteristics of selected fungi on polyvinyl film  

SciTech Connect

The objective of this study was to determine if plasticized polyvinyl chloride film would support the growth of any of nine species of fungi. The film was suspended in distilled water with no nutrients or with glucose or ammonium sulfate. Spores of each of the test species were inoculated into the suspension medium, and the mixture was incubated at 30/sup 0/C for up to 18 weeks. Most species were found to be capable of utilizing the film for carbon or nitrogen when the other nutrient was supplied. Only two species, Aspergillus fischeri and Paecilomyces sp., were found to be capable of utilizing components of the film without added nutrients. Components of the polyvinyl chloride film were then incorporated into mineral salts medium to determine if these components could serve as carbon sources in the presence of ammonium nitrate. The only component found to be utilized by all the fungi as a carbon source was epoxidized oil, a plasticizer-stabilizer. Calcium-zinc stearate was an available carbon source for all except the Penicillium and Verticillium strains. The only other component utilized was a stearamide, which was metabolized solely by the Aspergillus sp. Only the stearamide contained enough nitrogen to serve as a primary source in the film. The compound, however, did not support growth of fungi in the presence of glucose. It was theorized that either the nitrogen of the stearamide was more readily available to the fungi in the whole film due to the presence of trace nutrients or the nitrogen was supplied by exogenous sources.

Roberts, W.T.; Davidson, P.M.

1986-04-01

410

Growth characteristics of selected fungi on polyvinyl chloride film.  

PubMed Central

The objective of this study was to determine if plasticized polyvinyl chloride film would support the growth of any of nine species of fungi. The film was suspended in distilled water with no nutrients or with glucose or ammonium sulfate. Spores of each of the test species were inoculated into the suspension medium, and the mixture was incubated at 30 degrees C for up to 18 weeks. Most species were found to be capable of utilizing the film for carbon or nitrogen when the other nutrient was supplied. Only two species, Aspergillus fischeri and Paecilomyces sp., were found to be capable of utilizing components of the film without added nutrients. Components of the polyvinyl chloride film were then incorporated into mineral salts medium to determine if these components could serve as carbon sources in the presence of ammonium nitrate. The only component found to be utilized by all the fungi as a carbon source was epoxidized oil, a plasticizer-stabilizer. Calcium-zinc stearate was an available carbon source for all except the Penicillium and Verticillium strains. The only other component utilized was a stearamide, which was metabolized solely by the Aspergillus sp. Only the stearamide contained enough nitrogen to serve as a primary source in the film. The compound, however, did not support growth of fungi in the presence of glucose. It was theorized that either the nitrogen of the stearamide was more readily available to the fungi in the whole film due to the presence of trace nutrients or the nitrogen was supplied by exogenous sources.

Roberts, W T; Davidson, P M

1986-01-01

411

Investigation of optical loss changes in siloxane polymer waveguides during thermal curing and aging  

NASA Astrophysics Data System (ADS)

In high performance electronic systems, with increasing chip speed and larger number of processors, the system performance is being limited by off-chip metal interconnects. In such systems, optical interconnects are being considered to replace electrical interconnects because of their high capacity for bandwidth and due to having less constraints on link length. Polymer waveguides are attractive as an optical interconnect medium because they can enable low-cost and high-density interconnects, and can be relatively easily integrated into organic board-level processes. The optical loss in the polymer optical waveguides is the key criterion used to evaluate their performance. Although thermal curing and aging factors can change the optical loss of polymer waveguides significantly, there is limited study on the effect of those factors. Also the field-use conditions of an embedded optoelectronic package with these polymer waveguides have not been reported in existing literature. In this research, the relationship between optical loss variations in polymer waveguides with polymer properties during thermal curing is investigated. The evolution of degree-of-cure is determined from differential scanning calorimetry and compared to optical absorption from spectroscopy. Optical loss due to scattering mechanisms is related to local density fluctuations, which is studied using dielectric analysis. Optical loss measurements are conducted on both uncladded and cladded waveguides during isothermal cure, which result in certain optical loss trends. Based on the trends, the underlying mechanisms for the optical loss variations are proposed and a cure process schedule to realize the lowest optical loss is recommended. Process-induced thermal stresses can also affect the polymer waveguide by introducing stress birefringence. In this work, the stress-optical coefficients of the siloxane polymer are extracted and employed in a numerical modeling method to determine the stress-induced birefringence in an optical waveguide system. The outlined methodology is generic in nature and can be applied to different waveguide geometries, planarization materials, and substrate/board materials to assess how stress-induced birefringence can be minimized for a given polymer core material. This research also seeks to understand the effect of thermal aging in polymer waveguides, and develop an optical loss model to ensure that the optical performance over extended field-use conditions is within the optical loss budget. The thermal-aging dependent optical loss is determined for waveguide samples at several different accelerated temperature conditions. To determine the field-use conditions, the temperature distribution in the vicinity of the embedded laser and the polymer waveguide is determined. Using such thermal experimental data, the analytical reliability models were employed to determine the optical loss with time, and provide a practical way of determining whether the optical waveguides would perform within the optical loss budget during field-use conditions.

Hegde, Shashikant G.

412

Quantitative and high mass ToF-SIMS studies of siloxane segregation in hydrogel polymers using cryogenic sample handling techniques  

NASA Astrophysics Data System (ADS)

This paper examines the capabilities of cryogenic sample handling to examine composition and structure of hydrogel materials where siloxane components are central to the analysis. XPS analysis of multicomponent polymers with cryogenic sample handling following exposure to aqueous environments has revealed the composition and kinetics of near surface reorganization for siloxane and fluorocarbon containing polymers. In this study we report results from a ToF-SIMS protocol for cryogenic sample handling applied to the analysis of surface changes upon hydration/dehydration of hydrogel polymers. Comparison of results from angle dependent XPS and ToF-SIMS are discussed for a range of commercial soft contact lens materials. Both methods detected changes in surface chemistry between the hydrated (frozen) and dehydrated surfaces. Analysis of the hydrated surfaces detected polymer components indicative of the commercial formulation as well as ice clusters. Analysis of the dehydrated materials detected changes in surface chemistry relative to the hydrated surface in addition to loss of water due to sample dehydration. A quantitative standard additions method for ToF-SIMS data was used to determine submonolayer amounts of PDMS impurities at the surface of the hydrogels. ToF-SIMS analysis of a series of seven poly (allyl methacrylate-g-dimethylsiloxane), AMA-g-DMS, graft copolymers in the hydrated state revealed high mass oligomeric ion distributions for systems with bulk PDMS content greater than 25 wt.%. This marks the first time that detection of high mass oligomeric ion distributions from hydrated (frozen) surfaces has been reported. Analysis of the dehydrated surface detected formation of high mass oligomeric ion distributions for systems with PDMS bulk content greater than 15 wt.%, but only detected these ion distributions in wet (frozen) samples when the bulk concentration was greater than 25 wt.%.

Hook, Daniel J.; Valint, Paul L.; Chen, Lu; Gardella, Joseph A.

2006-07-01

413

Technical note Splinting for CDH—initial impressions of a 'user-friendly' alternative  

Microsoft Academic Search

A lightweight, washable, and easily adjusted splint for the congenitally dislocated hip, designed to improve maternal compliance, is described. Observations are currently scientifi­ cally uncontrolled, though initial impressions are favourable.

R. N. VILLAR; P. M. SCOTT; A. RONEN

1987-01-01

414

Splinting for CDH--initial impressions of a 'user-friendly' alternative.  

PubMed

A lightweight, washable, and easily adjusted splint for the congenitally dislocated hip, designed to improve maternal compliance, is described. Observations are currently scientifically uncontrolled, though initial impressions are favourable. PMID:3658656

Villar, R N; Scott, P M; Ronen, A

1987-08-01

415

Trait impressions as overgeneralized responses to adaptively significant facial qualities: evidence from connectionist modeling.  

PubMed

Connectionist modeling experiments tested anomalous-face and baby-face overgeneralization hypotheses proposed to explain consensual trait impressions of faces. Activation of a neural network unit trained to respond to anomalous faces predicted impressions of normal adult faces varying in attractiveness as well as several elderly stereotypes. Activation of a neural network unit trained to respond to babies' faces predicted impressions of adults varying in babyfaceness as well as 1 elderly stereotype. Thus, similarities of normal adult faces to anomalous faces or babies' faces contribute to impressions of them quite apart from knowledge of overlapping social stereotypes. The evolutionary importance of appropriate responses to unfit individuals or babies is presumed to produce a strong response preparedness that is overgeneralized to faces resembling the unfit or babies. PMID:12788687

Zebrowitz, Leslie A; Fellous, Jean-Marc; Mignault, Alain; Andreoletti, Carrie

2003-01-01

416

My Impressions of My American Colleagues. Reflections on My Ukranian Colleagues.  

ERIC Educational Resources Information Center

Presents a Ukrainian teacher's impressions of American English teaching, and an American high school English teacher's reflections about teaching English in the Ukraine. Notes the differences and similarities of teaching English in both countries. (SR)

Tarasova, Olena; Megyeri, Kathy

1999-01-01

417

The application of impressed current cathodic protection to historic listed reinforced concrete and steel framed structures  

Microsoft Academic Search

This paper describes some case studies of historic buildings and other structures treated with impressed current cathodic protection to provide long term corrosion control that is consistent with the requirements of conservation of listed buildings and monuments.

J. P. Broomfield

418

3D shape measurement of shoeprint impression with structured illumination and fringe pattern analysis  

NASA Astrophysics Data System (ADS)

The shoeprint impressions of suspect left at the crime scene can sometimes tell investigators what type of shoes to be looked for. These shoeprint impressions as one of the important evidence are useful in the detection of criminals. In this paper we propose a novel technique for identifying and analyzing the 3D characteristics of shoeprint impressions. We also design 3D shoeprint impression analysis system based on the combination the 3D shape measurement with structured illumination and fringe pattern analysis. We give a detail discussion on the principle and configuration of the system. Laboratory experiments show the technique is efficient in the detection of shoeprint and in the offering the reference for judicial evidence.

Su, Xianyu; Cao, Yiping; Xiang, Liqun; Chen, Wenjing

2002-06-01

419

Basilar impression and osteogenesis imperfecta in a three-year-old girl: CT and MRI  

Microsoft Academic Search

A 3-year-old girl with osteogenesis imperfecta developed symptomatic basilar impression. Her neurological symptoms were treated\\u000a by foramen magnum decompression and laminectomy. This is an unusually young patient to have this condition.

P. J. Rush; D. Berbrayer; B. J. Reilly

1989-01-01

420

A comparison of enhancement techniques for footwear impressions on dark and patterned fabrics(.).  

PubMed

The use of chemical enhancement techniques on porous substrates, such as fabrics, poses several challenges predominantly due to the occurrence of background staining and diffusion as well as visualization difficulties. A range of readily available chemical and lighting techniques were utilized to enhance footwear impressions made in blood, soil, and urine on dark and patterned fabrics. Footwear impressions were all prepared at a set force using a specifically built footwear rig. In most cases, results demonstrated that fluorescent chemical techniques were required for visualization as nonfluorescent techniques provided little or no contrast with the background. Occasionally, this contrast was improved by oblique lighting. Successful results were obtained for the enhancement of footwear impressions in blood; however, the enhancement of footwear impressions in urine and soil on dark and patterned fabrics was much more limited. The results demonstrate that visualization and fluorescent enhancement on porous substrates such as fabrics is possible. PMID:23786301

Farrugia, Kevin J; Bandey, Helen; Dawson, Lorna; Daéid, Niamh Nic

2013-06-20

421

21 CFR 872.3661 - Optical Impression Systems for CAD/CAM.  

Code of Federal Regulations, 2013 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3661 Optical Impression Systems for CAD...computer-assisted design and manufacturing of dental restorative prosthetic devices. Such systems may consist of a camera,...

2013-04-01

422

Investigation on Chromatic Mechanism Mediating the Whole Color Impressions from MultiColored Texture Patterns  

Microsoft Academic Search

We investigated the relationships between a single-color impression sensed for a multi-colored texture and the colors of elements embedded in the texture. The stimulus was a random-dot texture pattern made by two colors which were equal saturated color. We measured a single color impression as a whole of the pattern by an asymmetrical color matching method. If a single color

Shoji Sunaga; Yukio Yamashita

423

Social skills, distorted perception and being suspect: Studies in impression formation and the ability to deceive  

Microsoft Academic Search

Conclusion  This paper dealt with the relation between social skills and a) making a suspicious impression, b) the ability to deceive.\\u000a The results suggest that observers typically entertain perceptual distortion: introverted and socially anxious persons automatically\\u000a impress them as less credible while extroverts establish more credibility. Introverts and socially anxious people are more\\u000a likely to be designated as suspect in the

Aldert Vrij; Willem Winkel

1992-01-01

424

Evaluation of the color impression of colored texture patterns by a color naming method  

Microsoft Academic Search

We investigated the Munsell-hue ranges in which a single color impression as a whole could be sensed in multi-colored textures, by using random-dot texture patterns made by two kinds of colored dots with different Munsell-hue and constant Munsell-value (V=5\\/) and -chroma (C= \\/6). Observers reported first whether a single color impression as a whole was perceived in them or not.

Shoji SUNAGA; Yukio YAMASHITA

425

Crouching Theropods in Taxonomic Jungles: Ichnological and Ichnotaxonomic Investigations of Footprints with Metatarsal and Ischial Impressions  

Microsoft Academic Search

Tracks and traces of crouching theropods are rare, known from only three specimens from the Lower Jurassic of New England and the Lower to ?mid Jurassic of China. The New England specimens reveal manus, metatarsal and sub-crescentic ischial callosity impressions associated with Grallator-like tracks. The Chinese traces reveal metatarsal traces and a sub-triangular ischial callosity impression associated with Eubrontes-like tracks.

Martin Lockley; Masaki Matsukawa; Li Jianjun

2003-01-01

426

Clinical success rates for polyether crown impressions when mixed dynamically and statically  

Microsoft Academic Search

The purpose of this study is to compare success rates of dual-viscosity impressions for two types of mixing techniques of\\u000a the polyether elastomeric impression material. Additionally, influencing parameters on the success rates should be evaluated.\\u000a The expectation was that there would be no difference between the success rates for the two mixing techniques. Two centres\\u000a enrolled 290 subjects (727 teeth)

Marc Schmitter; Glen H. Johnson; Clovis Faggion Jr; Christina Klose; Gergo Mitov; Frank P. Nothdurft; Peter R. Pospiech; Peter Rammelsberg; Brigitte Ohlmann; Stefanie Schwarz; Thomas Stober; Petra Schiller; Maria Pritsch

427

Exceptional stegosaur integument impressions from the Upper Jurassic Morrison Formation of Wyoming  

Microsoft Academic Search

Dinosaur skin impressions are rare in the Upper Jurassic Morrison Formation, but different sites on the Howe Ranch in Wyoming\\u000a (USA), comprising specimens from diplodocid, camarasaurid, allosaurid and stegosaurian dinosaurs, have proven to be a treasure-trove\\u000a for these soft-tissue remains. Here we describe stegosaurian skin impressions from North America for the first time, as well\\u000a as the first case of

Nicolai A. Christiansen; Emanuel Tschopp

2010-01-01

428

Getting at the Truth or Getting Along: Accuracy Versus Impression-Motivated Heuristic and Systematic Processing  

Microsoft Academic Search

Two studies examined the heuristic and systematic processing of accuracy- versus impression-motivated individuals expecting a discussion with a partner believed to hold either a favorable or unfavorable opinion on the discussion issue. Given the goal of having a pleasant interaction, impression-motivated (versus accuracy-motivated) participants in both studies were particularly likely to express attitudes that were evaluatively consistent with the partner's

Serena Chen; David Shechter; Shelly Chaiken

1996-01-01

429

Impressions in cleft lip and palate--a novel two stage technique.  

PubMed

Though the field of presurgical orthopedics for the management of children with cleft Lip and Palate (CLAP) has made great advances over the past few decades, little is found in literature regarding the imressions required to fabricate these appliances. The purpose of this paper is to describe a novel two stage technique utilizing greenstick compound and addition silicone impression material to provide a safe, economical and accurate method for recording impressions in children with cleft lip and palate. PMID:19358372

Pani, Sharat Chandra; Hedge, Amitha M

2008-01-01

430

Evelyn Brooks Higginbotham - Elizabeth Fox-Genovese: First and Lasting Impressions - Common Knowledge 14:1  

Microsoft Academic Search

This memorial tribute reflects on the personal and intellectual qualities of Elizabeth Fox‐Genovese (1941–2007), who was the author's teacher. Higginbotham says that her first impressions of Fox‐Genovese, formed in a graduate seminar in European history at the University of Rochester in the mid‐1970s, have been lasting impressions. The seminar introduced patterns of thought and behavior that proved consistent over the

Evelyn Brooks Higginbotham

2008-01-01

431

Is Your Profile Picture Worth 1000 Words? Photo Characteristics Associated with Personality Impression Agreement  

Microsoft Academic Search

Social-Networking Websites (SNWs) are rapidly becoming a central media for social exchange. A basic question is how well are people able to get to know each other through these websites? In this study, we explore characteristics of the profile photographs and their association with impression agreement. Using a specially designed social networking website (http:\\/\\/www.YouJustGetMe.com), we examined 1,316 first- impressions of

Fitzgerald Steele Jr.; David C. Evans; Rachel K. Green

2009-01-01

432

Vision expert system 3D-IMPRESS for automated construction of three dimensional image processing procedures  

Microsoft Academic Search

In this paper a three dimensional (3D) image processing expert system called 3D-IMPRESS is presented. This system can automatically construct a 3D image processing procedure by using pairs of an original input image and a desired output figure called sample figure given by a user This paper describes the outline of 3D-IMPRESS and presents a method of procedure consolidation for

Xiang-Rong Zhou; Akinobu Shimizu; Jun-ichi Hasegawa; Jun-ichiro Toriwaki; Takeshi Hara; Hiroshi Fujita

2001-01-01

433

How Turn-Taking Strategies Influence Users' Impressions of an Agent  

Microsoft Academic Search

\\u000a Different turn-taking strategies of an agent influence the impression that people have of it. We recorded conversations of\\u000a a human with an interviewing agent, controlled by a wizard and using a particular turn-taking strategy. A questionnaire with\\u000a 27 semantic differential scales concerning personality, emotion, social skills and interviewing skills was used to capture\\u000a these impressions. We show that it is

Mark ter Maat; Khiet P. Truong; Dirk Heylen; Jan Allbeck; Norman Badler; Timothy Bickmore; Catherine Pelachaud; Alla Safonova

2010-01-01

434

77 FR 22847 - National Emission Standards for Hazardous Air Pollutants for Polyvinyl Chloride and Copolymers...  

Federal Register 2010, 2011, 2012, 2013

...distinct enough from polyvinyl chloride polymers that the EPA used the conjunctive...chloride copolymer is a highly crystalline polymer, making the removal or stripping of...resin more difficult than typical PVC polymers. The commenter stated that, to...

2012-04-17

435

Fluorine Magnetic Resonance Spectra and Tacticities of Poly(Vinyl Trifluoroacetate).  

National Technical Information Service (NTIS)

Fluorine magnetic resonance spectra of poly(vinyl trifluoroacetate) samples of different tacticities were investigated, along with those of model compounds. These polymers represent the first case where the line order in respect to stereostructure does no...

K. Fujii S. Brownstein A. M. Eastham

1968-01-01

436

Spectroscopic investigation of the thermal conversion of catalytically dehydrated polyvinyl alcohol  

SciTech Connect

The authors examine the structural conversion of dehydrated polyvinyl alcohol thermally treated at temperatures exceeding the temperature of the catalytic dehydration. The authors used electron and infrared spectroscopy to study the thermal conversion of catalytically dehydrated polyvinyl alcohol in an inert atmosphere and in air. Aluminum chloride and hydrogen chloride were used as catalysts of the dehydration. Spectra are shown which were obtained in the visible part from ALCL/sub 3/-containing polyvinyl alcohol films after their thermal treatment in an inert gas flow. It is shown that optimal temperatures must be selected to obtain high-quality recordings of optical information when the dehydration of polyvinyl alcohol is to be used to advantage.

Gavrilov, M.Z.

1986-09-01

437

40 CFR 61.65 - Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants.  

Code of Federal Regulations, 2010 CFR

...Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants. 61.65 Section 61.65 Protection...POLLUTANTS National Emission Standard for Vinyl Chloride § 61.65 Emission standard for ethylene...

2009-07-01

438

40 CFR 61.65 - Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants.  

Code of Federal Regulations, 2010 CFR

...Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants. 61.65 Section 61.65 Protection...POLLUTANTS National Emission Standard for Vinyl Chloride § 61.65 Emission standard for ethylene...

2010-07-01

439

Fluorescent nano particles in the aqueous phase by polymer analogous reaction of polyvinyl alcohol  

NASA Astrophysics Data System (ADS)

Polyvinyl alcohol (PVA) was condensed with perylene aldehydes to form functional nano particles. These are self-dispersing in the aqueous phase and form strongly fluorescent media with large Stokes' shifts caused by the interaction of chromophores. Applications are discussed.

Langhals, Heinz; Pust, Tim

2010-10-01

440

Detection of early xerophthalmia by impression cytology and rose Bengal staining--a comparative study.  

PubMed

Twenty two cases were studied for early detection of Xerophthalmia by impression cytology and Rose Bengal staining. Patients were below 6 years of age and admitted in the paediatric ward of Dhaka Medical College Hospital. Assessment were done by conjunctival impression cytology and staining with 1% Rose Bengal dye. Estimation of serum retinol level was done by HPLC to correlate conjunctival findings with biochemical status. The mean age of the subjects were 3.15 +/- 1.75. Rose Bengal staining was positive in 40% cases and impression cytology was in 60% cases. The mean serum retinol level of the diseased children were 10.5 +/- 3. ug/dl. The sensitivity of Rose Bengal staining was 53.3% and that of impression cytology was 80% in detecting vitamin A deficiency when compared with serum retinol level. The specificity of Rose Bengal staining was 40% and that of impression cytology was 100%. Sensitivity of impression cytology was 100% in patient with retinol level 10 ug/dl. PMID:1417661

Khan, A N; Huda, S; Ahmed, A N; Hossain, T; Sultana, N; Ali, S M

1992-04-01

441

Poly(vinyl chloride) (PVC) hollow fiber ultrafiltration membranes prepared from PVC\\/additives\\/solvent  

Microsoft Academic Search

Using poly(vinyl pyrrolidone) (PVP 40,000) or poly(ethylene glycol) (PEG) with different molecular weights (PEG 600, PEG 800, PEG 1000) as additives and N,N-dimethylacetamide (DMAc) as a solvent, asymmetric poly(vinyl chloride) (PVC) hollow fiber ultrafiltration membranes were prepared by phase inversion technique from 14 to 20wt.% solids including PVC and additives. The 95\\/5 DMAc\\/water and pure water were used as the

Jian Xu; Zhen-Liang Xu

2002-01-01

442

Organically crosslinked polyvinyl alcohol copolymetric gels for use under harsh reservoir conditions  

SciTech Connect

This patent describes a process for recovering oil from a subterranean oil-bearing formation having relatively high permeability zones and relatively low permeability zones penetrated by at least one production well in fluid communication with a substantial portion of the formation. It comprises: injecting into the formation an aqueous gel-forming composition comprising water, a water-dispersible polyvinyl alcohol copolymer, the polyvinyl alcohol copolymer selected from the group consisting of copolymers of vinyl alcohol and vinyl alkyl sulfonate either.

Haskin, D.H.; Shu, P.

1990-07-10

443

Hybrid material polyvinyl alcohol-copper oxide and its electrical properties  

NASA Astrophysics Data System (ADS)

The hybrid material polyvinyl alcohol-copper oxide was produced by the thermal decomposition of polyvinyl alcohol-copper hydroxide complex compound. It was analyzed by means of XRD, UV-VIS, IR, and Raman spectroscopy. It was concluded that the most part of copper oxide has an amorphous structure and consists of -(Cu-O) n - chains. The electrical properties of this material were investigated at direct and alternating current in 80-375 K temperature range.

Prosanov, I. Yu.; Bulina, N. V.; Chesalov, Yu. A.

2012-08-01

444

Preparation and characterization of processable electroactive polyaniline–polyvinyl alcohol composite  

Microsoft Academic Search

In this paper, the preparation and characterization of polyaniline–polyvinyl alcohol composites is described. The polyaniline composite was synthesized by chemical polymerization of aniline in media containing polyvinyl alcohol (10%, w\\/w). Oxidation of aniline results in a stable water based polyaniline dispersion, which can be cast to form a mechanically robust film.The electrical conductivity of the films increased with increasing amount

A Mirmohseni; G. G Wallace

2003-01-01

445

Radiation-chemical synthesis of poly(vinyl alcohol) hydrogel containing dicyclohexano-18-crown-6  

Microsoft Academic Search

Radiation-chemical synthesis of poly(vinyl alcohol) hydrogels containing physically immobilized dicyclohexano-18-crown-6 was carried out. Remarkable gel fraction of 40–70% was observed at absorbed dose of about 5kGy. Increasing degree of poly(vinyl alcohol) crosslinking led to growth of the efficiency of crown ether immobilization. Post-irradiation thermal annealing of the hydrogel samples at 120°C for 0.5–5h resulted in an increase of crown ether

O. A. Zakurdaeva; S. V. Nesterov; N. A. Shmakova; G. K. Semenova; E. O. Sozontova; V. I. Feldman

2007-01-01

446

Radiation-chemical synthesis of poly(vinyl alcohol) hydrogel containing dicyclohexano-18-crown-6  

Microsoft Academic Search

Radiation-chemical synthesis of poly(vinyl alcohol) hydrogels containing physically immobilized dicyclohexano-18-crown-6 was carried out. Remarkable gel fraction of 40 70% was observed at absorbed dose of about 5 kGy. Increasing degree of poly(vinyl alcohol) crosslinking led to growth of the efficiency of crown ether immobilization. Post-irradiation thermal annealing of the hydrogel samples at 120 °C for 0.5 5 h resulted in

O. A. Zakurdaeva; S. V. Nesterov; N. A. Shmakova; G. K. Semenova; E. O. Sozontova; V. I. Feldman

2007-01-01

447

Dimensional stability and detail reproduction of irreversible hydrocolloid and elastomeric impressions disinfected by immersion.  

PubMed

STATEMENT OF PROBLEM: Because irreversible hydrocolloid impressions imbibe blood and saliva, immersion rather than spray disinfection may be more effective. Polyether has been shown to be dimensionally sensitive to immersion disinfection. PURPOSE: The aim of this study was to determine whether irreversible hydrocolloid and polyether impressions could be disinfected by immersion without sacrificing accuracy and surface quality. MATERIAL AND METHODS: Impressions were made of a master mandibular arch containing a crown preparation. Changes between the master and working casts were assessed. Irreversible hydrocolloids (Jeltrate; Palgaflex), a polyether (Impregum F), and an addition silicone (President) were used. Disinfectants were an iodophor (Biocide), a glyoxal glutaraldehyde (Impresept de), and a phenol glutaraldehyde (Sporicidin). The control was without disinfection. Casts were formed in Type IV gypsum. The roughness of working dies was also recorded and an analysis of variance was used for statistical evaluation. Results. Casts from disinfected irreversible hydrocolloid and elastomeric impressions maintained accuracy for anteroposterior and cross arch dimensions where differences from the master was less than 0.1%. Buccolingual and mesiodistal dimensions of working dies (disinfected and control) were 6 to 8 microm larger than the master for addition silicones and 11 to 16 pm for polyethers. The occlusogingival dimension of dies for control and disinfected polyether was 9 pm longer than the master compared with -3 microm for addition silicone. The range of mean surface roughness of working dies made from irreversible hydrocolloids was 1.4 to 1.7 microm and ranged from 0.5 to 0.7 microm for elastomeric impressions. Conclusion. Immersion disinfection of Jeltrate material with iodophor and Palgaflex material with glyoxal glutaraldehyde produced casts and dies as accurate as the control. Control and disinfected elastomeric impression produced dies as clinically accurate and smooth as the master. Disinfection of irreversible hydrocolloid impressions with the glyoxal and phenol glutaraldehyde produced a surface smoother than controls. PMID:9576321

Johnson, G H; Chellis, K D; Gordon, G E; Lepe, X

1998-04-01

448

Transient response of microbial communities in a water well field to application of an impressed current.  

PubMed

Deterioration of water wells due to clogging and corrosion over time is a common problem where solutions may be costly and ineffective. Pilot studies have suggested that impressed current or cathodic protection may be used to reduce microbially-induced declines in water well performance. Two water wells in an alluvial aquifer close to the North Saskatchewan River were selected to study the response of subsurface microbial communities to the application of an impressed current as an anti-fouling technology. The treated well was exposed to an impressed current while the untreated well was used as a reference site. Biofilms grown on in situ coupons under the influence of the impressed current were significantly (p < 0.05) thicker (mean thickness = 67.3 ?m) when compared to the biofilms (mean thickness = 19.3 ?m) grown outside the electric field. Quantitative PCR analyses showed significantly (p < 0.05) higher numbers of total bacteria, iron- and nitrate-reducers in the electrified zone. Molecular analysis revealed that the predominant bacteria present in biofilms grown under the influence of the impressed current belonged to Rhodobacter spp., Sediminibacterium spp. and Geobacter spp. In addition to favouring the growth of biofilms, direct microscopic and ICP-AES analyses revealed that the impressed current also caused the deposition of iron and manganese on, and in the vicinity of, the well screen. Together, these factors contributed to rapid clogging leading to reduced specific pumping capacities of the treated well. The study revealed that the impressed current system was not effective as an anti-fouling technology but actually promoted both microbial growth and physical clogging in this aquifer. PMID:23206499

Medihala, P G; Lawrence, J R; Swerhone, G D W; Korber, D R

2012-11-21

449

Evaluation of impression accuracy for a four-implant mandibular model--a digital approach.  

PubMed

Implant-supported prosthodontics requires precise impressions to achieve a passive fit. Since the early 1990s, in vitro studies comparing different implant impression techniques were performed, capturing the data mostly mechanically. The purpose of this study was to evaluate the accuracy of three different impression techniques digitally. Dental implants were inserted bilaterally in ten polymer lower-arch models at the positions of the first molars and canines. From each original model, three different impressions (A, transfer; B, pick-up; and C, splinted pick-up) were taken. Scan-bodies were mounted on the implants of the polymer and on the lab analogues of the stone models and digitized. The scan-body in position 36 (FDI) of the digitized original and master casts were each superimposed, and the deviations of the remaining three scan-bodies were measured three-dimensionally. The systematic error of digitizing the models was 13 ?m for the polymer and 5 ?m for the stone model. The mean discrepancies of the original model to the stone casts were 124 ?m (±34)??m for the transfer technique, 116 (±46)??m for the pick-up technique, and 80 (±25)??m for the splinted pick-up technique. There were statistically significant discrepancies between the evaluated impression techniques (p ? 0.025; ANOVA test). The splinted pick-up impression showed the least deviation between original and stone model; transfer and pick-up techniques showed similar results. For better accuracy of implant-supported prosthodontics, the splinted pick-up technique should be used for impressions of four implants evenly spread in edentulous jaws. PMID:22009182

Stimmelmayr, Michael; Erdelt, Kurt; Güth, Jan-Frederik; Happe, Arndt; Beuer, Florian

2011-10-19

450

Ionic conductivity and electrochemical properties of cross-linked poly[siloxane- g-oligo(ethylene oxide)] gel-type polymer electrolyte  

Microsoft Academic Search

Poly[siloxane-g-oligo(ethylene oxide)] tetraacrylate cross-linker was synthesized, and the gel polymer electrolytes (GPE) was prepared by thermal curing using them. Increase of conductivity with decrease of Tg was observed as the content of liquid electrolyte increased. Maximum conductivity was found to be 3.92 × 10?3S\\/cm at 30°C with a 70wt.% 1M LiPF6 in EC\\/PC (1:1). The electrochemical stability of the resulting

Junkyoung Lee; Yongku Kanga; Dong Hack Suh; Changjin Lee

2004-01-01

451

Self-assembling siloxane bilayer directly on SiO2 surface of micro-cantilevers for long-term highly repeatable sensing to trace explosives  

Microsoft Academic Search

This paper presents a novel sensing layer modification technique for static micro-cantilever sensors that detect trace explosives by measuring specific adsorption-induced surface stress. For the first time, a method of directly modifying a siloxane sensing bilayer on an SiO2 surface is proposed to replace the conventional self-assembled monolayers (SAMs) of thiols on Au to avoid the trouble from long-term unstable

Ying Chen; Pengcheng Xu; Xinxin Li

2010-01-01

452

Synthesis and properties of a novel UV-cured fluorinated siloxane graft copolymer for improved surface, dielectric and tribological properties of epoxy acrylate coating  

NASA Astrophysics Data System (ADS)

A novel functional fluorinated siloxane graft copolymer bearing with vinyl end-groups was synthesized from dihydroxypropyl-terminated poly(dimethylsiloxane) (PDMS), dicarboxyl terminated poly(2,2,3,4,4,4-hexafluorobutyl acrylate) oligomer (CTHFA), 2,4-toluene diissocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA). The chemical structure was characterized by FT-IR and GPC. The effect of concentration of the vinyl-capped fluorosilicone graft copolymer (Vi-PFSi) on the surface, thermal properties, dielectric and tribological properties of UV-cured films was investigated. Contact angles and surface energies showed that the high hydrophobic and oleophobic surfaces were obtained by incorporation of Vi-PFSi at very low amount (0.5 wt%). X-ray photoelectron spectroscopy (XPS) evidenced that the fluorinated and siloxane moiety selectively migrated to the outermost surface of UV-cured film, thus reduced its surface energy from 45.42 to 15.40 mN/m2 without affecting its bulk properties. The morphology of fracture surface of modified film exhibited rough fracture surface only at the outermost surface, revealing fluorinated and siloxane groups migrated toward air-side surface. The dielectric constants decreased from 5.32 (1 MHz) for bisphenol-A epoxy methacrylate (EMA) to 2.82 (1 MHz) for modified film when the Vi-PFSi copolymer concentration increased from 0 to 0.8 wt%. Tribological results from abrasion tester suggested that the Vi-PFSi could obviously reduce the abrasion weight loss of modified films.

Yan, Zhenlong; Liu, Weiqu; Gao, Nan; Wang, Honglei; Su, Kui

2013-11-01

453

Polyvinyl alcohol functionalized cobalt ferrite nanoparticles for biomedical applications  

NASA Astrophysics Data System (ADS)

In the present work, cobalt ferrite nanoparticles (CoFe2O4 NPs) have been synthesized by combustion method. The surface of the CoFe2O4 NPs was modified with biocompatible polyvinyl alcohol (PVA). To investigate effect and nature of coating on the surface of CoFe2O4 NPs, the NPs were characterized X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The transmission electron microscopy (TEM) and dynamic light scattering (DLS) results demonstrate the monodispersed characteristics of CoFe2O4 NPs after surface modification with PVA. The decrease in contact angle from 162° to 50° with PVA coating on NPs indicates the transition from hydrophobic nature to hydrophilic. The Magnetic properties measurement system (MPMS) results show that the NPs have ferromagnetic behavior with high magnetization of 75.04 and 71.02 emu/g of uncoated and coated CoFe2O4 NPs respectively. These PVA coated NPs exhibit less toxicity over uncoated CoFe2O4 NPs up to 1.8 mg mL-1 when tested with mouse fibroblast L929 cell line.

Salunkhe, A. B.; Khot, V. M.; Thorat, N. D.; Phadatare, M. R.; Sathish, C. I.; Dhawale, D. S.; Pawar, S. H.

2013-01-01

454

The development and characterization of degradable poly(vinyl ester) and poly(vinyl ester)/PEO block copolymers  

NASA Astrophysics Data System (ADS)

The development of biodegradable materials is a challenging and important problem in polymer science. A review of the state of the art in degradable materials is presented, which reveals that current biodegradable materials do not exhibit the thermal or mechanical properties necessary for widespread applications. One strategy for toughening polymeric materials, which has previously been applied to non-degradable thermoplastics and thermoplastic elastomers, is the formation of block copolymers. Poly(vinyl esters) (PVE) homopolymers are known to have a wide range of properties, but PVE block copolymers comprise a class of inexpensive and (bio)degradable materials that were previously unknown. Therefore, the synthesis and properties of these block copolymers were explored in an effort to develop robust degradable materials. This thesis research probes the reaction conditions necessary for the reversible-addition fragmentation chain transfer (RAFT) polymerization and chain extension reactions of vinyl ester monomers. PVE di- and triblock copolymers are synthesized and studied, and the triblock copolymers display extremely poor toughness due to their relatively low molecular weights in light of the high entanglement molecular weight of the poly(vinyl acetate) center block. Attempts to improve the mechanical properties of these materials focus on the incorporation of poly(ethylene oxide) (PEO) as a low entanglement molecular weight and biocompatible center block in PVE-containing triblock copolymers. Depending on the choice of PVE endblocks and the overall polymer composition, crystallization of the PEO block can be controlled, confined, or inhibited. Polymers in which PEO crystallization is completely inhibited exhibit enhanced mechanical properties and behave as weak thermoplastics. In order to understand the relationship between the inhibition of PEO crystallization and the mechanical properties of PVE/PEO materials, these polymers were studied using dynamic mechanical spectroscopy, wide angle X-ray scattering, small angle X-ray scattering, differential scanning calorimetry, and uniaxial tensile tests. By combining insights gained from these techniques, a complex picture emerges that explains the enhanced mechanical properties of these materials based on the type and location of thermal transitions, amorphous PEO entanglements, and the strain-induced crystallization of PEO. This work represents an important step toward developing robust materials with tunable properties containing (bio)degradable components.

Lipscomb, Corinne Elizabeth

455

Survey of Impression Materials and Techniques in Fixed Partial Dentures among the Practitioners in India.  

PubMed

Objective. Anecdotal evidence suggests that impression materials and techniques used in general dental practice for fixed partial dentures vary from those taught in dental schools. The aim of this survey was to integrate impression techniques evolved all over the years for fixed partial dentures and to know the techniques and materials which are used in the present day by the practitioners. Materials and Methods. A total of 1000 questionnaires were sent to various practitioners in India, out of which 807 questionnaires were filled. Results. The results showed that 84.8% of prosthodontists (65.56%, urban areas) use elastomeric impression materials as well as irreversible hydrocolloids and 15.2% use irreversible hydrocolloid only. Amongst other practitioners, 55.46% use irreversible hydrocolloid (45%, rural and semiurban areas) and 44.54% use elastomeric impression materials. Elastomeric impression technique practiced most commonly is putty reline with/without spacer (77.2%); other techniques are multiple-mix and monophase techniques. Conclusion. The ideal materials, technique, and armamentarium are required for the long-term success of the treatment for fixed partial denture. Also, if the ideal procedure is not followed, it will lead to a compromised fit of the final prosthesis and failure of the treatment. PMID:23691334

Moldi, Arvind; Gala, Vimal; Puranik, Shivakumar; Karan, Smita; Deshpande, Sumit; Neela, Neelima

2013-04-22

456

Survey of Impression Materials and Techniques in Fixed Partial Dentures among the Practitioners in India  

PubMed Central

Objective. Anecdotal evidence suggests that impression materials and techniques used in general dental practice for fixed partial dentures vary from those taught in dental schools. The aim of this survey was to integrate impression techniques evolved all over the years for fixed partial dentures and to know the techniques and materials which are used in the present day by the practitioners. Materials and Methods. A total of 1000 questionnaires were sent to various practitioners in India, out of which 807 questionnaires were filled. Results. The results showed that 84.8% of prosthodontists (65.56%, urban areas) use elastomeric impression materials as well as irreversible hydrocolloids and 15.2% use irreversible hydrocolloid only. Amongst other practitioners, 55.46% use irreversible hydrocolloid (45%, rural and semiurban areas) and 44.54% use elastomeric impression materials. Elastomeric impression technique practiced most commonly is putty reline with/without spacer (77.2%); other techniques are multiple-mix and monophase techniques. Conclusion. The ideal materials, technique, and armamentarium are required for the long-term success of the treatment for fixed partial denture. Also, if the ideal procedure is not followed, it will lead to a compromised fit of the final prosthesis and failure of the treatment.

Moldi, Arvind; Puranik, Shivakumar; Karan, Smita; Deshpande, Sumit; Neela, Neelima

2013-01-01

457

Reducing job insecurity and increasing performance ratings: Does impression management matter?  

PubMed

Prior research on job insecurity has demonstrated its detrimental effects on both employees and the organization, yet no research has detailed how people actively deal with it. Drawing from proactivity research, this article argues that job insecurity prompts a proactive use of impression management tactics in the workplace. The effectiveness of these tactics depends on the level of supervisory liking for the employee and the attributions supervisors make regarding the employee's motives for the impression management behaviors (i.e., for the good of the organization or for self-interest). A 3-wave survey study of 271 Chinese employees and their supervisors showed that employees experiencing job insecurity in Time 1 reported using a variety of tactics to impress their supervisors at Time 2 and that these tactics curbed the affect associated with job insecurity and enhanced supervisor rated performance, through supervisor's liking and attributed motives. The relationship between impression management and increased supervisor-rated performance was moderated by supervisor attributions; the relationship between impression management and reduced affective job insecurity depended on supervisor liking. (PsycINFO Database Record (c) 2013 APA, all rights reserved). PMID:23731028

Huang, Guo-Hua; Zhao, Helen Hailin; Niu, Xiong-Ying; Ashford, Susan J; Lee, Cynthia

2013-06-03

458

Permeation of gases through composite membranes prepared by radio-frequency and microwave plasma polymerization of siloxanes  

NASA Astrophysics Data System (ADS)

In this work, the permeation of gases and condensible vapors through composite membranes was studied. Helium, hydrogen, argon, oxygen, nitrogen, methane, carbon dioxide, ethylene, acetylene, sulfur dioxide, propane, n-butane and sulfur hexafluoride were used as permeant gases. Composite membranes were prepared by the deposition of either radio-frequency or microwave plasma polymerized siloxanes onto polymer substrates of porous Celgard. The starting monomer was either hexamethy1disiloxane (HMDSO) or octamethyl-cyclotetrasiloxane (OMCTSO). The films were characterized by FTIR, ESCA, TGA, density and contact angle measurements. The permeabilities of the of the microwave and radio-frequency plasma polymerized siloxane membranes for thirteen gases were measured and compared. The permeabilities were similar to those for conventional PDMS. Temperature and pressure dependence of permeability was measured. From the temperature dependence of permeability, activation energies for permeation were calculated. These were positive except for permeation of butane in RF PPHMDSO, which was negative. The activation energies were lower than for conventional PDMS. The permeabilities did not strongly depend on pressure up to 42 psia. It was observed that permeabilities for gases showed dependence on molecular size, but the correlation was not as strong as for plasma polymerized fluorocarbon membranes. As molecular size increased from 2.58 A (helium) to 5.6 A (sulfur hexafluoride), the permeabilities of the membranes exhibited a decreasing trend. Within a group of permeant gases of similar size, e.g. argon, oxygen and nitrogen, or methane and carbon dioxide, the permeabilities increased with critical temperature. It was also observed that the solubility parameter, delta, correlated with the permeability for gases having similar molecular size. The density of the films increased in the order: RF PPHMDSO < microwave PP HMDSO < microwave PP OMCTSO. Permeabilities decreased, and O2/N 2 selectivity increased, as the density of the plasma polymer films increased. Permeation of butane through RF PPHMDSO showed unusual behavior. The permeation activation energy was negative. Butane permeation reduced the permeability of the membrane to nitrogen by 15%. After a 24 hour period the permeability returned to normal.

Lal, Akhil

459

Basilar impression as a possible cause of cerebellar stroke: case report.  

PubMed

A case is reported of a 72-year-old woman who presented with severe vertigo, vomit, and mild neck and occipital pain. She had a medical history of hypertension, angina pectoris, cholelithiasis, gastric ulcer, pyelonephritis and periodical mild dizziness. Neuroimaging revealed right vertebral artery occlusion, right cerebellar stroke and basilar impression. The therapeutic approach chosen in our patient was conservative, with non-steroid anti-inflammatory drugs and neck collar. Although our patient's prior risk factors for stroke supported a diagnosis of vertebrobasilar stroke, it is possible that the vertebral artery occlusion was the result of changes in the atlantoaxial anatomy and that cerebellar infarction was secondary to craniocervical anomaly. Although the presence of vertebral artery occlusion, cerebellar stroke and basilar impression in our patient may have been coincidental, we suggest that patients with basilar impression and craniocervical anomalies in general may be at an increased risk of vertebrobasilar vascular disease and vertebrobasilar stroke. PMID:22649889

Roje-Bedekovi?, Marina; Vargek-Solter, Vesna; Bedek, Darko; Demarin, Vida

2011-12-01

460

In vitro study of transmission of bacteria from contaminated metal models to stone models via impressions.  

PubMed

The purpose of this study was to determine the risk of microbiological transmission into the dental laboratory via impressions and dental stone models. Metal master models were contaminated with Bacillus subtilis and Streptococcus sanguis. Impressions in alginate, polyvinylsiloxane, and polyether were used, and models were cast in two brands of dental stone. Samples were taken from the impression surfaces before and after casting, and sections from the stone models were taken by a technique developed for this study. After incubation, the numbers of colonies were counted and the numbers of colony-forming units per milliliter were calculated. The reductions were statistically significant but considered to be clinically insignificant. The conclusion is that even after severe contamination, the risks to dental laboratory personnel are minimal. "Normal" hygienic procedures are recommended instead of disinfection. PMID:12271350

Sofou, A; Larsen, T; Owall, B; Fiehn, N-E

2002-08-16

461

Sensitivity of Perianal Tape Impressions to Diagnose Pinworm (Syphacia spp.) Infections in Rats (Rattus norvegicus) and Mice (Mus musculus)  

PubMed Central

We determined the sensitivity of perianal tape impressions to detect Syphacia spp. in rats and mice. We evaluated 300 rat and 200 mouse perianal impressions over 9 wk. Pinworm-positive perianal tape impressions from animals with worm burdens at necropsy were considered as true positives. Conversely, pinworm-negative perianal tape impressions from animals with worm burdens were considered false negatives. The sensitivity of perianal tape impressions for detecting Syphacia muris infections in rats was 100%, and for detecting Syphacia obvelata in mice was 85.5%. Intermittent shedding of Syphacia obvelata ova is the most probable explanation for the decreased sensitivity rate we observed in mice. We urge caution in use of perianal tape impressions alone for Syphacia spp. screening in sentinel mice and rats.

Hill, William Allen; Randolph, Mildred M; Mandrell, Timothy D

2009-01-01

462

New holographic polymeric composition based on plexiglass, polyvinyl butyral, and phenanthrenquinone  

NASA Astrophysics Data System (ADS)

The newly developed Plexiglas films containing polyvinyl butyral resins and phenanthrenequinone molecules as photosensitive dopant, which are proposed for the practical application as interlayer of laminated safety glass, are shown for the first time. The injection of the phenanthrenequinone-poly(methyl methacrylate) into the polyvinyl butyral protective interlayer provides a homogenous distribution of the recording holographic medium in the layer and allows fixing the entire surface grating in the laminated glass. In addition, the original properties of polyvinyl butyral as a connecting material were preserved during manufacturing of the laminated glass. This allows a recording of holographic structures directly after baking of the laminated glass, thus reducing the destruction of the gratings due to the elevated temperatures. The diffractive structures in phenanthrenequinone-poly(methyl methacrylate)-polyvinyl butyral polymeric layers with thicknesses of hundreds of microns are sealed between two panels of glass (so-called laminated glass) and are generated by illumination with an Argon-laser of 514 nm. Efficiently fixed and long-term stable holographic gratings recorded in the phenanthrenequinone-poly(methyl methacrylate)-polyvinyl butyral layer enable to produce transparent laminated glass with inserted diffractive elements, which can be used e.g. for Head-up Displays in automobile windshields or as holographic light concentrators for solar cells.

Matusevich, Vladislav; Tolstik, Elen; Kowarschik, Richard; Egorova, Elena; Matusevich, Yuri I.; Krul, Leonid

2013-05-01

463

Achieving Desired Images While Avoiding Undesired Images: Exploring the Role of Self-Monitoring in Impression Management  

Microsoft Academic Search

A study was conducted to test the hypothesis that high self-monitors more effectively manage impressions than low self-monitors do. Students in work groups indicated the extent to which they used 5 impression-management tactics over the course of a semester-long project. At the project’s conclusion, students provided their perceptions of the other members of their group. The relationship between impression management

William H. Turnley; Mark C. Bolino

2001-01-01

464

Integrated Modular Propulsion and Regenerative Electro-energy Storage System (IMPRESS) for small satellites  

SciTech Connect

The IMPRESS is a significant advancement in space system technology as it is able to operate alternately as a fuel cell to produce electrical power from stored hydrogen and oxygen and as a water electrolyzer using electrical power to produce hydrogen and oxygen from stored water. The electrolysis of a controllable fraction of stored water can provide high Isp rocket propellants on demand. The heart of the IMPRESS is the Unitized Regenerative Fuel Cell (URFC), which produces power and electrolytically regenerates its reactants using a single stack of reversible cells. This integrated approach has several significant advantages over separate (battery) power and propulsion systems.

Mitlitsky, F. [Lawrence Livermore National Lab., CA (United States); de Groot, W. [Nyma, Inc., Brook Park, OH (United States); Butler, L.; McElroy, J. [United Technologies Corp., Windsor Locks, CT (United States). Hamilton Standard Div.

1996-09-01

465

Manufacturing processes for athletic shoe outsoles and their significance in the examination of footwear impression evidence.  

PubMed

The most common methods of manufacturing athletic shoe outsoles are given and how each method can influence the examination of footwear impression evidence. Several processes for manufacturing athletic shoe outsoles are described. Significant factors of each process that are relevant to the examination of footwear impressions are explained. Some manufacturing processes result in distinguishing random characteristics which can assist in the identification of a shoe sole, even when new. These characteristics, together with the traditionally observed wear patterns and random cuts on the shoe outsoles, enable the examiner a stronger basis for expert opinion. PMID:3944559

Bodziak, W J

1986-01-01

466

[A case of brainstem and cerebellar infarctions related to basilar impression].  

PubMed

We report a 30-year-old man presenting with medial longitudinal fasciculus (MLF) syndrome after an afternoon nap. Magnetic resonance imaging revealed a right medial pontine tegmental infarction and right cerebellar infarctions. This patient was complicated with basilar impression detected on cervical X-ray and MRI. Three-dimensional CT angiography disclosed that the odontoid process migrated into the posterior fossa, thrusting the bilateral vertebral arteries postero-laterally. The mechanical stress on the bilateral vertebral arteries may have caused infarctions in the territories of the posterior circulation of this patient with basilar impression. PMID:15233275

Kasai, Takashi; Yoshikawa, Kenji; Tachibana, Shunji; Taniguchi, Takuya; Nakagawa, Masanori

2004-03-01

467

Laboratory performance of zinc anodes for impressed current cathodic protection of reinforced concrete  

SciTech Connect

Cathodic protection is used increasingly to mitigate steel reinforcement corrosion in concrete. the performance of zinc materials as impressed current anodes was evaluated. The anode materials investigated included rolled zinc sheets, metallized zinc, and 85% Zn-15% Al. The circuit resistance and the adhesion of the anodes was monitored with polarization time. Overall performance of arc-sprayed zinc was good. However, its adhesion to the concrete surface slowly decreased as the current density, or the polarization period, increased. Penny blank sheets and metallized 85% Zn-15% Al were found unsuitable as impressed current anodes.

Brousseau, R.; Arnott, M.; Baldock, B. [National Research Council of Canada, Ottawa, Ontario (Canada)

1995-08-01

468

Applicants' preference for impression management tactic in employment interviews by Transportation Security Administration.  

PubMed

Following past findings on employment interviews, this study hypothesized applicants would have a preference for using self-promoting tactics of impression management over other focuses. Self-reports of impression management tactics were collected from 124 applicants who had interviews for screener positions with the Transportation Security Administration. Contrary to the hypothesis, analysis indicated participants reported they used more ingratiation tactics attempting to praise the interviewer than self-promotion tactics which focused on their own accomplishments. Special qualifications for security jobs which required well-developed perceptual abilities and the controlling structure of the interview context were perhaps responsible for present results differing from prior findings. PMID:19610468

Scudder, Joseph N; Lamude, Kevin G

2009-04-01

469

Development of a direct three-dimensional biomicrofabrication concept based on electrospraying a custom made siloxane sol  

PubMed Central

We demonstrate here the discovery of a unique and direct three-dimensional biomicrofabrication concept possessing the ability to revolutionize the jet-based fabrication arena. Previous work carried out on similar jet-based approaches have been successful in fabricating only vertical wall?pillar-structures by the controlled deposition of stacked droplets. However, these advanced jet-techniques have not been able to directly fabricate self-supporting arches?links (without molds or reaction methods) between adjacent structures (walls or pillars). Our work reported here gives birth to a unique type of jet determined by high intensity electric fields, which is derived from a specially formulated siloxane sol. The sol studied here has been chosen for its attractive properties (such as an excellent cross-linking nature as well as the ability to polymerize via polycondensation on deposition to its biocompatability), which promotes direct forming of biostructures with nanometer (<50 nm) sized droplets in three dimensions. We foresee that this direct three-dimensional biomicrofabrication jet technique coupled with a variety of formulated sols having focused and enhanced functionality will be explored throughout the physical and life sciences.

Sullivan, Alice C.; Jayasinghe, Suwan N.

2007-01-01

470

Plasma surface modification of fibroporous polycarbonate urethane membrane by polydimethyl siloxane: Structural characterization, mechanical properties, and in vitro cytocompatibility evaluation.  

PubMed

This article reports the surface modification of electrospun polycarbonate urethane membrane with polydimethyl siloxane (PDMS) using plasma-induced grafting technique for biomedical applications. The nonwoven membranes were characterized for their structure, performance, and compatibility with cells. The surface modification was confirmed by means of attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and energy dispersive X-ray analysis (EDXA). ATR-FTIR and EDXA analyses displayed characteristic absorption peaks of PDMS for the membrane. The structure and morphology of the developed membranes were studied using scanning electron microscope and microcomputed tomography (µCT). Scanning electron microscopy and µCT revealed the fibrous morphology and percentage porosity of the membranes before and after plasma modification. Static mechanical tests showed that the tensile strength was greater than 8 MPa. Physical characterization of the membranes after immersion in hydrolytic and oxidative media supports their biostability. Cytotoxicity of the membrane was evaluated using L929 fibroblast cells, and the results indicated that the membrane is cytocompatible. Accordingly, these results highlight the potential of this fibrous membrane for biomedical applications. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013. PMID:23650270

Arjun, G N; Menon, Girish; Ramesh, P

2013-05-01

471

Compatibilization of polystyrene and poly(dimethyl siloxane) with a star polymer having a ?tcyclodextrin core and polystyrene arms  

NASA Astrophysics Data System (ADS)

Cyclodextrins (CDs) are cyclic starch molecules having a hollow central cavity which can be threaded by a polymer to form an inclusion compound. This characteristic is exploited in a new type of compatibilizer: a star polymer with a ?tCD core and polystyrene (PS) arms. Atom transfer radical polymerization is used to grow and control the size of the PS arms from brominated initiator sites on ?tCD. Solutions and thin films of PS and poly(dimethyl siloxane) (PDMS) are compatibilized by this CD-star. The mechanism of compatibilization involves threading of the CD core by PDMS and solubilization of the resulting ``slip-ring graft copolymer'' via the PS star arms. Compatibilization of PS/PDMS in chloroform is visually observed when the initially turbid suspensions become clear solutions after addition of CD-star. Thin films spin-cast from these solutions exhibit a high degree of homogeneity and a nanoscale level of mixing. The solutions are characterized with NMR, dynamic light scattering and intrinsic viscosity measurements, and the thin films are characterized with optical and atomic force microscopy. Many different polymers are capable of threading the CD core, thus the same CD-star molecule could be used to compatibilize several different threading polymers with the same matrix polymer.

Balik, C. M.; Tonelli, A. E.; Busche, Brad

2010-03-01

472

Poly(dimethyl siloxane) surface modification by low pressure plasma to improve its characteristics towards biomedical applications.  

PubMed

Poly(dimethyl siloxane) elastomer, (PDMS) is widely used as a biomaterial. However, PDMS is very hydrophobic and easily colonized by several bacteria and yeasts. Consequently, surface modification has been used to improve its wettability and reduce bacterial adhesion. The aim of this work was to modify the PDMS surface in order to improve its hydrophilicity and bacterial cell repulsion to be used as a biomaterial. Plasma was used to activate the PDMS surface and sequentially promote the attachment of a synthetic surfactant, Pluronic F-68, or a polymer, Poly(ethylene glycol) methyl methacrylate, PEGMA. Bare PDMS, PDMS argon plasma activated, PDMS coated with Pluronic F-68 and PEGMA-grafted PDMS were characterized by contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The influence of the surface modifications on blood compatibility of the materials was evaluated by thrombosis and haemolysis assays. The cytotoxicity of these materials was tested for mouse macrophages. After modification, AFM results suggest the presence of a distinct layer at the surface and by the contact angle measures it was observed an increase of hydrophilicity. XPS analysis indicates an increase of the oxygen content at the surface as a result of the modification. All the studied materials revealed no toxicity and were found to be non-haemolytic or in some cases slightly haemolytic. Therefore, plasma was found to be an effective technique for the PDMS surface modification. PMID:20638249

Pinto, S; Alves, P; Matos, C M; Santos, A C; Rodrigues, L R; Teixeira, J A; Gil, M H

2010-06-25

473

Surface modification of Sylgard-184 poly(dimethyl siloxane) networks by ultraviolet and ultraviolet/ozone treatment.  

PubMed

We report on the surface modification of Sylgard-184 poly(dimethyl siloxane) (PDMS) networks by ultraviolet (UV) radiation and ultraviolet/ozone (UVO) treatment. The effects of the UV light wavelength and ambient conditions on the surface properties of Sylgard-184 are probed using a battery of experimental probes, including static contact angle measurements, Fourier transform infrared spectroscopy, near-edge X-ray absorption fine structure, and X-ray reflectivity. Our results reveal that when exposed to UV, the PDMS macromolecules in the surface region of Sylgard-184 undergo chain scission, involving both the main chain backbone and the side groups. The radicals formed during this process recombine and form a network whose wetting properties are similar to those of a UV-modified model PDMS. In contrast to the UV radiation, the UVO treatment causes very significant changes in the surface and near-surface structure of Sylgard-184. Specifically, the molecular oxygen and ozone created during the UVO process interact with the UV-modified specimen. As a result of these interactions, the surface of the sample contains a large number of hydrophilic (mainly -OH) groups. In addition, the material density within the first approximately 5 nm reaches about 50% of that of pure silica. A major conclusion that can be drawn from the results and analysis described in this work is that the presence of the silica fillers in Sylgard-184 does not alter the surface properties of the UVO- and UV-modified Sylgard-184. PMID:12702402

Efimenko, Kirill; Wallace, William E; Genzer, Jan

2002-10-15

474

Aligned electrospun siloxane-doped vaterite/poly(l-lactide) composite fibremats: evaluation of their tensile strength and cell compatibility.  

PubMed

Siloxane-doped vaterite (SiV)/poly(l-lactide) hybrid-composite (SiPVH) has been developed in our group as the bone repair material and successfully fabricated into a non-woven electrospun fibremat. The aim of this work is to prepare aligned electrospun SiPVH fibremats with varied SiV content and compare their tensile properties and cell compatibilities using mouse osteoblast-like cells. It was observed that the maximum stress exhibited some non-linear trend as a function of SiV content: the highest stress value was reached with 30?wt.% SiV and decreased significantly with more than 40?wt.% SiV. Cellular morphology and proliferation were taken under examination on both aligned and random electrospun SiPVH fibremats. The cells started to orient themselves only 3?h after seeding on the aligned fibremat and they continued to elongate along the fibres. The number of the cells cultured up to seven days on both random and aligned fibremats was well comparable; therefore the alignment did not show negative effect on the cellular proliferation. PMID:23914946

Tujunen, Noora-Maria; Fujikura, Kie; Obata, Akiko; Kasuga, Toshihiro

2013-08-06

475

Preparation and characterization of polyvinyl alcohol—chitosan biocompatible magnetic microparticles  

NASA Astrophysics Data System (ADS)

This work addresses the obtaining of biocompatible magnetic polyvinyl alcohol—chitosan microspheres, specifically tailored/functionalised to bind directly blood toxins using an emulsion crosslinking preparation method. The following synthesis parameters were studied: water to oil phase ratio, polyvinyl alcohol molecular weight, chitosan to polyvinyl alcohol weight ratio, surfactant composition and concentration of the crosslinking agent. These parameters were optimized for producing a high yield of colloidally stable and uniformly sized particles with significant magnetization of saturation, bearing surface amino groups that can be further used to bind blood toxins directly. The particles were characterized regarding their size distribution and surface charge (laser diffraction analysis), morphology (transmission electron microscopy), magnetic properties, chemical composition (Fourier transform infrared spectroscopy) and concentration of the surface amino groups (conductometric titration).

Elena Udrea, Laura; Hritcu, Doina; Popa, Marcel Ionel; Rotariu, Ovidiu

2011-01-01

476

Stress Strengthens Memory of First Impressions of Others' Positive Personality Traits  

Microsoft Academic Search

Encounters with strangers bear potential for social conflict and stress, but also allow the formation of alliances. First impressions of other people play a critical role in the formation of alliances, since they provide a learned base to infer the other's future social attitude. Stress can facilitate emotional memories but it is unknown whether stress strengthens our memory for newly

Johanna Lass-Hennemann; Linn K. Kuehl; André Schulz; Melly S. Oitzl; Hartmut Schachinger; André Aleman

2011-01-01

477

Birth injury: a possible contributory factor in the aetiology of primary basilar impression  

PubMed Central

Adult patients with primary basilar impression were four times more likely to have a history of birth injury than a control group. Distortion of basicranial synchondroses during birth is suggested as a possible mechanism and, in association with hindbrain herniation and arachnoid adhesions, may contribute towards the development of syringomyelia.

Battersby, Robert De; Williams, Bernard

1982-01-01

478

Impression-Oriented Music Courseware and Its Application in Elementary Schools  

ERIC Educational Resources Information Center

|Purpose: The purpose of this paper is to present the design and implementation of music courseware that features a music search system that uses impression keywords. The paper applies the courseware to "Kansei" (sensibility) development for elementary and junior high school students. The objectives of this courseware are to cultivate children's…

Sasaki, Shiori; Watagoshi, Kiku; Takano, Kosuke; Hirashima, Kazuo; Kiyoki, Yasushi

2010-01-01

479

The stability of evoked sense-impression responses to verbal stimuli  

Microsoft Academic Search

In a series of studies (Bourisseau, Davis, & Yamamoto, 1965; Otto, 1962; Otto & Britton, 1964) data were reported concerning the relative effectiveness of different modes of stimulus presentation in evoking sense-impression responses. In those investigations subjects were shown 35 printed words each of which was a concrete noun. As each noun was presented subjects were instructed to respond with

David H. Bauer

1972-01-01

480

An experimental exploration of the relationship between subjective impressions of illumination and physical fidelity  

Microsoft Academic Search

Two experiments were carried out to explore the effect of rendering and interface fidelity on subjective impressions of illumination and perceived presence after exposure to a virtual environment (VE). In particular, a study that compares a real-world task situation to its computer graphics simulation counterpart is presented. The computer graphics simulation was based on photometry data acquired in the real-world

Katerina Mania; Andrew Robinson

481

Impact of Internet Images: Impression-Formation Effects of University Web Site Images  

ERIC Educational Resources Information Center

|Institutions of higher education are increasingly becoming dependent on Web-based marketing to reach out to their target audiences. The current empirical study examines the types of impressions formed by prospective students based on exposure to different university Web site images. A between-subjects experiment was conducted using four identical…

Ramasubramanian, Srividya; Gyure, James F.; Mursi, Nasreen M.

2002-01-01

482

Lasting First Impressions: A Qualitative Study of Freshmen Arrival on Campus.  

ERIC Educational Resources Information Center

|This qualitative study examined the experiences and impressions of first-time freshmen at Boise State University (BSU) in Idaho. Twenty-five freshmen completed weekly open-ended interviews, kept journals, and participated in an end-of-term group meeting during the fall term of 1996. The results indicated that most students found getting…

Michener, Barbara; Belcheir, Marcia J.

483

Removal of latex glove contaminants prior to taking poly (vinylsiloxane) impressions.  

PubMed

Sulfur compounds found in latex gloves may be deposited on teeth and gingiva, inhibiting the setting of poly(vinylsiloxane) impression materials. The objective of this in vivo study was to screen a variety of methods to remove these contaminants. Ten patients were each tested with eight decontamination methods. Before each trial, the facial surfaces and adjacent gingiva of the maxillary central and lateral incisors were contaminated with 20 wipes of a latex glove. Decontamination methods included a 30-second rinse with mouthwash, 3% hydrogen peroxide, or air-water syringe; a 30-second toothbrush scrub with water, mouthwash, or hydrogen peroxide; a 30-second cotton pellet-Cavidry scrub; and a 30-second cleaning with a prophy cup and pumice. A 10-second water rinse followed each method except the air-water syringe and Cavidry groups. A low-viscosity poly(vinylsiloxane) impression material was then used to take an impression of the area. To test surface inhibition, the gingival, tooth, and palatal impression surfaces were wiped with cotton-tipped applicators, and the degree of inhibition was subjectively categorized by two independent investigators. Mechanical decontamination with a toothbrush or pumice was significantly more effective than was rinsing alone, regardless of the solution used. PMID:7568684

Browning, G C; Bromme, J C; Murchison, D F

1994-11-01

484

The effect of maize starch on setting time of vinyl polysiloxane putty impression materials.  

PubMed

Maize starch is widely used as a glove lubricant, and the belief is commonly held that it is responsible for retarding the setting reaction of vinyl polysiloxane putty impression material (VPPIM). In contrast, our research demonstrated experimentally that maize starch glove lubricant (MSGL) did not inhibit but significantly (P less than 0.05) accelerated the setting reaction of VPPIM. PMID:2637003

Touyz, L Z; Rosen, M

1989-09-01

485

Impact of Clothing on Impressions of Personal Characteristics and Writing Ability  

Microsoft Academic Search

The study was designed to determine if attractive clothing had a more positive effect than unattractive clothing on a perceiver's impressions of the personal characteristics of the writer of an essay and the qualities of the essay. Perceivers who assigned high interest\\/importance to clothing were expected to favorably rate both personal characteristics of an attractively dressed writer and the essay.

Mary Lapitsky; Cynthia M. Smith

1981-01-01

486

The influence of dental gloves on the setting of impression materials.  

PubMed

The increased wearing of gloves during dental treatment has created new problems for general dental practitioners. One of these is the retarded set or total inhibition of addition silicones caused by natural latex gloves. This study was designed to test different gloves and impression materials in common use. Eight latex gloves, selected with different properties representing all possible types, together with four non-latex gloves, made of neoprene, styrene-butadiene, polyethylene and polyvinylchloride, were tested. As a control, mixing with bare hands and with maize starch was carried out. The viscosity changes of five types of impression materials (polyvinylsiloxanes, condensation silicones, alginates, polyether and polysulphides) were measured with a Zwick hardness tester to give the Shore A hardness. No impression materials other than polyvinylsiloxanes were affected by pure latex gloves and those only by two brands. All other impression materials can be mixed and handled with gloved hands without affecting their setting time. The retarded set of polyvinylsiloxanes caused by natural latex gloves is not so widespread as had previously been thought. PMID:7546957

Baumann, M A

1995-08-19

487

Clothing Fashionability and Students with a Disability: Impressions of Social and Mental Competencies  

Microsoft Academic Search

The purpose of this research was to investigate the effect of clothing fashionability and gender of a student with a disability, in combination with a perceiver's gender and affiliation with an individual with a disability, upon impressions of social and mental competencies of a student with a disability. Subjects were 183 undergraduates who each received a questionnaire and photograph depicting

Donna J. Nisbett; Kim K. P. Johnson

1992-01-01

488

Effect of Clothing on the Use of Person Information Categories in First Impressions  

Microsoft Academic Search

The present study investigated the relative strength of perceiver and target person variables on person information categories used in first impressions. Descriptions of four target persons written by fifty-two females were content analyzed according to person information categories. Comparisons were made in amount of overlap in categories used when one perceiver described two target persons (1 on 2) dressed to

Leslie D. Burns; Sharron J. Lennon

1993-01-01

489

Impressions of Personality Based on Body Forms: An Application of Hillestad's Model of Appearance  

Microsoft Academic Search

The purpose of this research was to investigate whether impressions ofpersonality varied by size and shape of male and female body forms. Three hundred eighty-five male and female undergraduates served as subjects. Each subject received a questionnaire with a line drawing attached. Each drawing was either a male or a female previously rated by judges as representing an ectomorphic (thin),

Kim K. P. Johnso