bluuebunny/crossref_metadata_2025 huggingface dataset:
DISTRIBUTION OF ECONOMIC RESOURCES: IMPLICATIONS OF INCLUDING HOUSEHOLD PRODUCTION
Authors: Bonke Jens
Published: March 2005

The value of household production is estimated to 40–50 percent of GNP in most western countries, and because the distribution of this income‐in‐kind is different from ordinary income distribution, the concept of economic well‐being may include household production. The monetary value of household production is evaluated by a market alternative principle and an opportunity‐cost principle. In the last case a reservation wage is estimated, and integrated in a modified opportunity principle, which means that household work of non‐working women is evaluated by the reservation wage, and household work of working women and men by their wage‐rate. The conclusions are among others, that the inclusion of household production reduces the inequality, and that the women's contributions—money income and household production—functions as income equalizers.
THE DISAGGREGATION OF THE GIN1 COEFFICIENT BY FACTOR COMPONENTS AND ITS APPLICATIONS TO AUSTRALIA
Authors: Podder Nripesh
Published: March 2005

This paper demonstrates the proper use of the disaggregation of the Gini coefficient by factor components by deriving a formula of the elasticity of the Gini coefficient with respect to specific income components. The method is then applied to Australian household expenditure survey data to find the effects of various components of income on overall income inequality. The results are important in examining the effects of growth in specific components on the overall inequality and hence in policy decisions with respect to redistribution of income.
POVERTY, TNEQUALTTY, AND FAMTLY LIVING STANDARDS IMPACTS ACROSS SEVEN NATIONS: THE EFFECT OF NONCASH SUBSIDIES FOR HEALTH, EDUCATION AND HOUSING
Authors: Smeeding Timothy M. , Saunders Peter , Coder John , Jenkins Stephen , Fritzell Johan , Hagenaars Aldi J. M. , Hauser Richard , Wolfson Michael
Published: March 2005

The main aim of this paper has been to summarize the impact of noncash income–health and health education benefits, and imputed rent‐on living standards, income distribution and poverty in seven nations at the beginning of the 1980s using the Luxembourg Income Study database. Our results do not give rise to a pattern of national differences in poverty rates or income inequality which are markedly different from that which emerges from previous LIS research based on cash income alone. While these results may be sensitive to the techniques used to measure and value noncash benefits in this paper, it appears that noncash income reinforces the redistributive impact or conventional (cash) tax‐transfer mechanisms rather than acting to offset them in any major way.
U.S. INCOME MOBILITY IN THE SEVENTIES AND EIGHTIES
Authors: Hungerford Thomas L.
Published: March 2005

This paper focuses on three questions: (1) Was mobility within the income distribution in the 1980s different from the 1970s? (2) Is there as much mobility when some measure of permanent income is used? and (3) Does movement within the income distribution imply real income changes'? Income mobility between 1969 and 1976, and between 1979 and 1986 is examined using real family income from the Panel Study of Income Dynamics. The results show that there is considerable movement within the income distribution when both annual and permanent income is used. This movement, however is generally not very great in either direction.
IMPUTED RENT AND INCOME DISTRIBUTION
Authors: Yates Judith
Published: March 2005

This paper uses unit record survey data to implement a 1977 United Nations recommendation that imputed rent from owner‐occupied housing be included in household income in statistics collected for income distribution purposes. The conceptual difficulties associated with employing the recommended National Accounts approach are highlighted by a comparison of the methodologies used to impute housing income for National Accounts purposes, for use in income distribution analyses and for income taxation purposes. The empirical difficulties associated with implementing the preferred approach are also discussed. The results reinforce the significant impact owner‐occupation has on the well‐being of many households and point to the importance of a disaggregate analysis of its distributional impact.
ZAKAT AND INEQUALITY: SOME EVIDENCE FROM PAKISTAN
Authors: Jehle Geoffrey A.
Published: March 2005

Zakat is an important form of religiously‐mandated charity under Islam. This paper examines its impact on income inequality in Pakistan. Data from 1987–88 are used to construct two income distributions‐one that would have obtained if zakat had not been given, and one that did obtain when such giving took place. Atkinson‐Kolm‐Sen relative indices of income inequality are computed which show that zakat does reduce measured income inequality in Pakistan. Both intra‐province and inter‐province components of over‐all inequality decline, though the amount of change is small.

So give to the kinsman his due, and to the needy, and to the wayfarer. That b best for those who seek Allah's countenance.

The Koran
A RESEARCH AND DEVELOPMENT MODULE SUPPLEMENTING THE NATIONAL ACCOUNTS
Authors: Bos Frits , Hollanders Hugo , Keuning Steven J.
Published: March 2005

This paper presents a national accounting framework that is tailored to a description of the role of Research and Development (R&D) in the national economy. The main differences from the standard national accounts are some changes in basic concepts and the introduction of additional, more detailed, classifications. The framework facilitates drawing macro‐economic conclusions from all kinds of data on R&D. Figures presented in this way can serve as a data base for modelling the role of R&D in the national economy.
AN EXPLORATORY COMPARISON OF INCOME RISK IN GERMANY AND THE UNITED STATES
Authors: Bird Edward J.
Published: March 2005

Using longitudinal data, 1 estimate the impact of redistribution on the welfare cost of income risk in Germany and the United States. The estimates account fully for behavior because individuals in each country have responded optimally to that country's policy. The results indicate that the welfare cost of income risk is 5.4 percent of disposable income in Germany, 8.5 percent in the U.S. Redistribution has reduced these risks from their pre‐tax, pre‐transfer levels by 43 percent in Germany, 21 percent in the U.S. The political importance of income security is evident in both countries, as risk relief often eliminates the net burden of redistributive taxes among middle‐class households. The conclusions are robust across several models of income expectations.
HOW INCOME INEQUALITY CHANGED IN GERMANY FOLLOWING REUNIFICATION: AN EMPIRICAL ANALYSIS USING DECOMPOSABLE INEQUALITY MEASURES
Authors: Schwarze Johannes
Published: March 2005

This paper analyzes how inequality in Before and After Government income has changed in Germany since reunification using the 1990 through 1992 waves of the German Socio‐Economic Panel. A Theil decomposable inequality index is used to measure inequality in Germany and in its eastern and western states. Massive public transfers from west to east have narrowed the east‐west income gap, substantially offset the rise in income inequality from private sources, and lowered overall inequality in the western states. The net result of this policy has been a drop in After Government income inequality in Germany between 1990 and 1992.
SELF‐EMPLOYMENT AND WEALTH INEQUALITY
Authors: Lindh Thomas , Ohlsson Henry
Published: March 2005

Is the decision to become and stay self‐employed constrained by access to credit? If this is the case, a more unequal wealth distribution will—for empirically observed distributions–imply more self‐employed, since the number of people able to provide collateral will be higher. Swedish data between 1920 and 1992 suggest that wealth inequality and the share of self‐employed among those working are positively related. The data, therefore, are consistent with the hypothesis that liquidity constraints are binding on the decision to become and stay self‐employed.
HOUSEHOLD NEEDS AND POVERTY: WITH APPLICATION TO SPAIN AND THE U.K.
Authors: Duclos Jean‐Yves , Mercader‐Prats Magda
Published: March 2005

We examine the sensitivity of U.K.‐Spanish poverty comparisons to variations in the dependence of equivalence scales on household size and composition, using evidence from national household budget surveys. We sum up these comparisons using subjective confidence levels. Taking into account the dissimilarities in the distribution of incomes and needs across countries, we find, inter alia, that although the poor are typically more numerous in Spain than in Britain, the actual headcount differences may vary by up to 10 percent of the population when needs allowances are altered, even when kept the same across the two countries. Comparisons of poverty composition across the two countries are also very sensitive to the choice of equivalence scale parameters. Generally, however, the proportion of single adults among the poor is much less important in Spain than in Britain, the reverse being true for households with three or more adults.
NEW ESTIMATES OF HOURS OF WORK AND REAL INCOME IN CANADA FROM THE 1880s TO 1930: LONG‐RUN TRENDS AND WORKERS' PREFERENCES
Authors: Altman Morris
Published: March 2005

The first set of hours of work estimates constructed for Canada and its regions for the 1880–1930 period is presented in this article. These estimates suggest a trend decline in hours of work, especially following First World War. In addition, these estimates suggest that the decline in hours of work came at no or little cost in terms of real weekly income. The trends uncovered for Canada are found to be similar to those revealed for the U.S. In effect, by the early twentieth century workers were realizing their long expressed preferences for a shorter workweek at no loss in real income.
ON OUTPUT OF THE SWEDISH EDUCATION SECTOR: ADDITIONAL REMARKS
Authors: Aronsson Thomas , Löfgren Karl‐Gustaf , Marklud Pre‐Olov
Published: March 2005

The main purpose of this paper is to relate the empirical attempt of measuring output from the education sector to theoretical results about the welfare significance of an extended net national product (NNP) measure. We show that economic theory provides a more focused way of interpreting such output estimates, which has not been recognized in previous studies. The paper also contains new estimates of the output from the Swedish education sector.
MEASURING POVERTY AND DEPRIVATION IN SOUTH AFRICA
Authors: Klasen Stephen
Published: March 2005

This paper compares a standard expenditure‐based poverty measure with a specifically created composite measure of deprivation using household survey data from South Africa. While there is a strong overall correlation between expenditures and levels of deprivation, the correlation is much weaker among the worst‐off South Africans. In addition, the two measures differ considerably in the impact of race, headship, location (urban, rural), and household size on expenditure poverty versus deprivation. In general, the deprivation measure finds more Africans, rural dwellers, members of de facto female‐headed households, and members of smaller households deprived than expenditure poor. Only the differences in the effect of household size on poverty are sensitive to assumptions about equivalence scales. As a result, the two measures diverge greatly in identifying the poorest and most deprived sections of the population, which may have considerable consequences for targeting.
ESTIMATION OF THE STOCK OF CAPITAL IN SPAIN
Authors: Mas Matilde , Pérez Francisco , Uriel Ezequiel
Published: March 2005

The paper presents the methodology and results of the estimation of the endowments of capital in the Spanish economy. It distinguishes between endowments of public capital and private capital. The series corresponding to the public sector cover the period 1955–97 and consider seven categories (or functions). The estimates are disaggregated by 17 regions and 50 provinces. The level of disaggregation is regional and provincial (NUTS2 and NUTS3 in European terminology). The private capital series cover the period 1964–97 and consider 17 sectors of production, with disaggregation at regional level. The information refers to two variables: gross formation of fixed capital (in current and constant pesetas) and capital stock in constant pesetas (base year 1990).
The Effect of Abutment Angulation on Stress Transfer for an Implant
Authors: Clelland Nancy L. , Gilat Amos
Published: March 2005

Purpose This investigation compared the stress production characteristics of five abutment angulations for a specific implant system.

Materials and Methods Photoelastic resin was cast directly to a 3.75 × 10‐mm Branemark fixture (Nobelpharma USA, Inc, Chicago, IL) in a 50 × 70 × 13‐mm mold. A strain gauge rosette was also incorporated in the resin to allow precise determination of normal stresses at a specific point. Each 4‐mm abutment (15°, 25°, and 35° from Implant Innovations (West Palm Beach, FL) and 0° and 30° from Nobelpharma) was assembled on the fixture, subjected to 178N load, and viewed with a circular polariscope. Observed fringes were photographed and strain indicator readings were recorded.

Results Mean observed fringe order and mean principal stress and strain at the location of the rosette were determined.

Conclusions At the location of the rosette, all five of the abutments produced principal strains (compressive and tensile) within the physiological zone for bone. The rosette was located approximately 4 mm away from the fixture. Higher stresses and strains can be expected in regions closer to the implant.
The Accuracy of Six Impression Techniques for Osseointegrated Implants
Authors: Barrett Mark G. , de Rijk Waldemar G. , Burgess John O.
Published: March 2005

Purpose Six impression techniques were evaluated using tapered and square impression copings.

Materials and Methods The absolute distortion was measured using a cast metal impression tray with fiduciary reference points external to the impression material. Measurements of the x, y, z coordinates on the master cast and the impressions were directly made with a travelling digitizing microscope. The difference between the coordinates of each of six sites in the impression and the corresponding reference site were compared.

Results There was no significant difference between the techniques for the square copings but that there was a significant loss of accuracy in the z‐axis with the tapered copings.

Conclusions No significant differences were noted.
Oral Electrical Burns: Etiology, Histopathology, and Prosthontic Treatment
Authors: Linebaugh Michael L. , Koka Sreenivas
Published: March 2005

Oral electrical burns occur predominantly in young children and may lead to permanent disfigurement. The etiology and histopathology of oral electrical burns are discussed. Prosthodontic treatment options are presented to provide clinical guidelines for the practitioner.
Accuracy of Irreversible Hydrocolloid Impression Material Mixed With Disinfectant Solutions
Authors: Ramer Michael S. , Gerhardt Donald E. , McNally Kathy
Published: March 2005

Purpose Irreversible hydrocolloid is capable of resisting contamination by viruses and saliva when the disinfectant iodine or the disinfectant chlorhexidine is added to the water being used to mix the material. This study investigates the accuracy of alginate impressions made with water to which either of the two disinfectants has been added.

Materials and Methods A total of 30 casts were made from an impression of a master cast. Ten impressions were made using water according to the manufacturer's instructions, ten were made using water to which iodine had been added, and ten were made using water to which chlorhexidine had been added. A measuring microscope was used to measure three different dimensions on each cast. Each measurement was repeated three times, and the average was used to compute the mean and standard deviation for each measured dimension. The data were statistically evaluated using a one‐way analysis of variance.

Results There was no statistical difference in the accuracy of irreversible hydrocolloid impressions mixed with water or with either of two disinfectant solutions.

Conclusion Accurate casts can be obtained when either of the two disinfectants are incorporated into the alginate impression material.
A Comparison of the Tensile Strength of Four Prosthodontic Adhesives
Authors: Diaz‐Arnold Ana M. , Mertz James M. , Aquilino Steven A. , Ryther Jeffrey S. , Keller John C.
Published: March 2005

Purpose This study compared the in vitro tensile bond strength of four prosthodontic adhesives to sandblasted base‐metal alloy.

Materials and Methods Alloy cylinders were bonded end‐to‐end with the various adhesives, thermocycled, stored for 28 days, and subjected to a tensile load.

Results Mean tensile bond strengths obtained were: Panavia = 42.3 MPa, Metabond = 31.1 MPa, All‐Bond = 28.06 MPa, and F21 = 18.5 MPa. Statistical analysis showed significant differences (P < .05) in mean bond strengths between the adhesive systems.

Conclusion Under the conditions of this study, the Panavia system showed the strongest mean tensile bond strengths.
Management of the Maxilla After Alveolar Ridge Augmentation With Hydroxylapatite When Opposed by Mandibular Implants
Authors: Gates William D. , Scurria Mark S. , Terry Bill C.
Published: March 2005

Maxillary ridge augmentation and vestibuloplasty are often adjuncts to mandibular implant reconstructions. Careful management of the augmented ridge after surgery is critical to the success of the maxillary prosthesis and osseointegration of the mandibular implant. A technique is described for alteration of an existing maxillary complete denture after ridge augmentation. Precautions regarding prosthesis function during the osseointegration phase of different types of mandibular reconstructions are noted. Technique and rationale for denture flange modification when a prosthesis is rebased for a patient who received simultaneous vestibuloplasty and ridge augmentation are described.
Modified Bar Superstructure for an Implant‐Retained Orbital Prosthesis
Authors: Khan Zafrulla , Bowden Mark , Beam David
Published: March 2005

The success of a bar superstructure for an orbital prosthesis may be compromised by the placement and angulation of implants. The following technique describes a modification to a bar superstructure that provided the advantages of convenience, security, and consistent positioning even though one implant was lost and the angulation of implants limited accuracy.
Effect of Restoration Composition, Shade, and Thickness on the Cure of a Photoactivated Resin Cement
Authors: Myers Michael L. , Caughman W. Frank , Rueggeberg Frederick A.
Published: March 2005

Purpose

This study investigates the effect of selected properties of a restorative material (type, shade, and thickness) on the cure of a photoactivated resin cement.

Materials and Methods

Disks of ceramic and resin‐based restorative materials of two extreme shades were made to provide thicknesses of 0.5 to 3.0 mm in 0.5‐mm intervals. Light transmission was measured through various thicknesses and shades of each restorative material type. The effect of light transmission, as influenced by restorative material type, shade, and thickness on resin cement cure was also determined.

Results

Thickness and shade of restorative material had the greatest influence on light transmission. For simulated restoration thicknesses 1.5 mm and greater, Dicor (Dentsply International Inc, York, PA) had greater transmission of light than the other materials, regardless of shade. At equal restorative material thicknesses, light transmission was similar for identical shades of the other three materials. Restoration shade and thickness also had the greatest influence on resin cement cure. Material type, although significant, had only a minor influence. At thicknesses of 1 to 2 mm, Dicor consistently yielded greater resin cement cure values than any other material tested.

Conclusions

When considering the ability of restorative materials to transmit light for curing of photo‐activated resin cements, the thickness of the restoration and its shade are much more influential than the choice of restorative material. Dicor provides greater light transmission that results in the ability to photobond restorations of greater thicknesses than the other materials. For restorations greater than 1 mm in thickness, a dual cure or chemical cure resin cement should be used to provide maximal cement properties.
Cross‐Sectional Design and Fatigue Durability of Cantilevered Sections of Fixed Implant‐Supported Prostheses
Authors: Stewart Robert B. , Staab George H.
Published: March 2005

Purpose Characterizing the fatigue behavior of cantilevered implant‐supported prostheses requires an understanding of both the material and its intended application. The relationships between applied load, component geometry, and the fatigue characteristics of a specific material often can be difficult to establish. Four different cross‐sectional designs of cantilevered frameworks used clinically were tested for fatigue durability, and the results were compared with theoretical tip deflections and stresses.

Materials and Methods Fatigue tests were conducted on specimens with I‐, U‐, and L‐shaped and elliptical cross‐sections after static stress analysis. Specimens with uniform cantilevered length were sprued, invested, and cast from the same high‐palladium alloy. Statistical results, SEM evaluation of fracture surfaces, and theoretical predictions provided further insight into the framework design.

Results Based on intraoral space restrictions, corrections for dimensional changes inherent in casting, the mean number of cycles to failure for each cross‐sectional geometry, and the performance of design groups as predicted by static analysis can be ranked in order from best to worst as I, L, U, and then elliptical. SEM evaluation showed varying degrees of porosity and shrinkage cavities specific to the specimen cross‐sections.

Conclusions Four designs for the cantilevered sections of implant‐supported frameworks were evaluated for fatigue durability and were compared with the results of the theoretical analysis. As tested, fatigue durability was predictable when compared with theoretical calculations of tip deflection and normal stress. Although all four shapes have considerable merit for rigidity, in limited intermaxillary conditions, the I‐ and L‐shaped cross‐sections may optimize performance and use of space.
Informed Consent for the Prosthodontic Patient With Temporomandibular Disorders
Authors:   Report of the Committee on Temporomandibular Disorders of the American College of Prosthodontists, Kinderknecht Keith E. , Hilsen Kenneth L.
Published: March 2005

The prosthodontic treatment of patients with a history of temporomandibular disorders presents unique risk‐management problems because of the varied nature, uncertain prognosis, and frequent recurrence of these disorders. Patients with temporomandibular disorders frequently require managed treatment over extended periods of time and may complicate the delivery and outcome of prosthodontic treatment. Informed consent is needed to protect both the patient and the prosthodontist because it facilitates proper communication, goal setting, and cooperation. The purpose of this article is to discuss the essential elements of informed consent and to present an informed consent program useful in the prosthodontic treatment of patients with temporomandibular disorders.
Dental Management of Neonates Requiring Prolonged Oral Intubation
Authors: von Gonten Ann Sue , Meyer Jack B. , Kim Andre K.
Published: March 2005

An orotracheal route is frequently the preferred method of intubation for premature infants. Nasal intubation may contribute to airway obstruction and possible hypoxia, further contributing to labored breathing. Additional complications include occlusion of the nasal aperture during a crucial period of development, nasal infections, and hypertrophy of the nasal lining. Oral mucosa is less susceptible to damage than nasal mucosa; however, orotracheal tubes must be stabilized against displacement from tongue and jaw movements to prevent discomfort and subsequent tissue trauma. Problems associated with rehabilitation of very‐low‐birth‐weight neonates and other infants requiring long‐term oral intubation include palatal grooving, acquired cleft palate, and damage to the primary dentition. Various intraoral aids have been used to reduce pressure application from intubation and feeding tubes on the palatal tissues. References to these procedures have yet to be reported in the prosthodontic literature. This article presents a rationale for design and construction of an intraoral device which protects the palatal tissues and stabilizes the orotracheal tube.
Effect of Dynamic Loading Methods on Cement Film Thickness In Vitro
Authors: Yu Zhaokun , Strutz Judith M. , Kipnis Victor , White Shane N.
Published: March 2005

Purpose Reduced cement film thicknesses can improve crown seating and decrease marginal discrepancies. Improved marginal adaptation has the potential to reduce plaque accumulation, periodontal disease, and cement dissolution. Studies have indicated that dynamic seating methods can reduce seating discrepancies associated with zinc phosphate and resin cements. However, other types of cements and other dynamic techniques have not yet been studied or compared, nor has the mechanism for improved seating been fully explained. Therefore, the purpose of this study was to investigate the effect of a variety of loading methods on the film thicknesses of current types of crown and fixed partial denture cements compressed between glass plates.

Materials and Methods This study investigated the effect of three dynamic loading methods on film thickness of six representative fixed prosthodontic cements. These included zinc phosphate, resin‐modified glass ionomer, encapsulated glass ionomer, adhesive composite resin, composite resin, and polycarboxylate. The method was derived from American Dental Association specifications for cement film thickness. In control groups, the cements were placed between two glass plates and statically loaded with a 15‐kg weight. The test groups were initially similarly loaded, and then for 30 seconds further subjected to simulated repeated patient opening and closing, vibrations from an electromallet, or an ultrasonic device.

Results Mean film thicknesses ranged from 7.4 μm for polycarboxylate/ultrasound up to 40.3 μm for composite resin/static. Two‐way analysis of variance revealed that the effects of material type and cementation method and their interaction all significantly affected film thickness (P < .0001). Multiple range analysis showed that dynamic methods were generally superior to static loading and that the ultrasonic method was the best overall.

Conclusions The different dynamic loading methods all significantly decreased cement film thicknesses between glass plates. The ultrasonic method was the most effective. The type of cement used also influenced film thickness. Composite resins were more affected than other materials.
Certification of the Dental Technician and Dental Laboratory: Issues Affecting the Dental Technology Field
Authors:   A Report by the Laboratory Relations Committee of the American College of Prosthodontists, Fehling A. W. , Schneider Robert L. , Depner John P.
Published: March 2005

Board certification in any health care–related area is one mechanism that promotes high standards of practice and assures public confidence. Certification eligibility and requirements for dental technicians and laboratories are reviewed. Issues affecting the future of dental technology are discussed.
A Review of Fiber‐Reinforced Denture Base Resins
Authors: Vallittu Pekka K.
Published: March 2005

Purpose One method of reinforcing denture base material is to use fiber composite reinforcement. Different types of fibers, such as glass (GF), carbon/graphite, aramid, and ultrahigh‐modulus polyethylene (UHMP) fibers have been tested for this purpose.

Materials and Methods This article reviews the studies conducted on the fiber‐reinforced denture base resin systems.

Results The literature has reported that the fiber concentration and its adhesion to polymer matrix influences the transverse strength of the fiber composite. The highest transverse strength value (265 MPa) with polymethyl methacrylate (PMMA) was obtained by incorporating 58 wt% GF into the resin. UHMP fibers incorporated into PMMA resin yielded the highest impact strength value (134 kJm‐2) of the fiber‐PMMA composites.

Conclusions Despite the improved mechanical properties of fiber‐reinforced denture materials, further research is required to show the clinical usefulness of the fiber reinforcement.
A Bimaxillary Sports Mouthguard: A Modified Technique
Authors: Milward Paul J. , Jagger Robert G.
Published: March 2005

The bimaxillary mouthguard provides enhanced protection for a participant in contact sports. This article describes the fabrication of a polyvinylacetate‐polyethylene (PVAc‐PE) bimaxillary mouthguard in which the connection of the maxillary and mandibular components is reinforced by pressure thermoforming a 2‐mm PVAc‐PE sheet over the labial and buccal portions of the mouthguard.
Using a Colorimeter to Develop an Intrinsic Silicone Shade Guide for Facial Prostheses
Authors: Over Larry M. , Andres Carl J. , Moore B. Keith , Goodacre Charles J. , Muñoz Carlos A.
Published: March 2005

Purpose To determine if using CIE L*a*b* color measurements of white facial skin could be correlated to those of silicone shade samples that visually matched the skin. Secondly, to see if a correlation in color measurements could be achieved between the silicone shade samples and duplicated silicone samples made using a shade‐guide color formula.

Materials and Methods A color booth was designed according to ASTM specifications, and painted using a Munsell Value 8 gray. A Minolta colorimeter was used to make facial skin measurements on 15 white adults. The skin color was duplicated using custom‐shaded silicone samples. A 7‐step wedge silicone shade guide was then fabricated, representing the commonly encountered thicknesses when fabricating facial prostheses. The silicone samples were then measured with the Minolta colorimeter. The readings were compared with the previous L*a*b* readings from the corresponding patient's skin measurements, and the relative color difference was then calculated. Silicone samples were fabricated and analyzed for three of the patients to determine if duplication of the visually matched silicone specimen was possible using the silicone color formula, and if the duplicates were visually and colorimetrically equivalent to each other. The color difference Delta E and chromaticity was calculated, and the data were analyzed using a coefficient‐of‐variation formula expressed by percent. A Pearson Product Moment Correlation Coefficient was performed to determine if a correlation existed between the skin and the silicone samples at the p .05 level.

Results The highest correlation was found in the b* dimension for silicone thicknesses of 1 to 4 mm. For silicone thicknesses of 6 to 10 mm, the highest correlation was found in the L* dimension. All three dimensions had positive correlations (R2 > 0), but only the 1‐mm and 4‐mm b* readings were very strong. Patient and silicone L*a*b* measurement results showed very little change in the a* axis, while the L* and b* measurements showed more change in their numbers, with changes in depth for all patient silicone samples. Delta E numbers indicated the lowest Delta E at the 1‐mm depth and the highest Delta E at the 10‐mm depth. All duplicated samples matched their original silicone samples to a degree that visual evaluation could not distinguish any color differences. Using volumetric measurements, a shade guide was developed for all 15 patients.

Conclusions There was good correlation between the patient's colorimeter measurements and the silicone samples, with the b* color dimension the most reproducible, followed by the L* and the a*. Silicone samples at 6, 8, and 10 mm matched the patient the best, and this study showed that silicone samples can be duplicated successfully if a good patient‐silicone match is obtained. Rayon flocking fibers and liquid makeup are effective at matching facial prostheses and can be used to develop a simple shade guide for patient application.
Compressive and Tensile Zones in the Cement Interface of Full Crowns: A Technical Note on the Concept of Resistance
Authors: Wiskott H. W. A. , Krebs C. , Scherrer S. S. , Botsis J. , Belser U. C.
Published: March 2005

Purpose

The objectives of the study were: 1) to map the stresses acting on the cement interface of crown and abutment analogs during loading; and 2) to provide a theoretical basis for the hypothesis that resistance to lateral dislodgment is a function of the distribution of compressive force vectors acting on the cement lute.

Materials and Methods

Three‐dimensional finite element (FE) meshes of crown and abutment analogs were constructed and loaded in a direction perpendicular to the axes of symmetry of the abutments. Three parameters were investigated: taper (10° and 20° of convergence), abutment substrate (Ni‐Cr alloy and dentin), and type of cement (zinc oxide eugenol, zinc phosphate, glass ionomer, and composite resin). The tensile and compressive components of the resulting force systems were plotted along two axes (z: parallel to the axis of symmetry of the crown/abutment complex; and y: perpendicular to z, ie, parallel to the direction of loading). Von Mises stresses were also generated.

Results

First, it was shown that the restoration's axis of rotation was located inside the abutment cone and was perpendicular to and intersected the axis of symmetry of the crown/abutment complex. Second, stress distribution was dependent on the three parameters investigated. Varying taper led to shifts due mainly to alterations in specimen geometry, whereas the abutment substrate and the cement type had a bearing on the level of the axis of rotation. The smaller the modulus of elasticity of the abutment substrate or the cement lute, the farther apical the location of the axis of rotation.

Conclusions

Conventional schemes for explaining crown dislodgment in which the restoration rotates around an axis located at the preparation margin should be reassessed. The results of the FE analysis are compatible with the hypothesis that resistance to lateral dislodgment is a function of the distribution of compressive force vectors acting on the cement interface.
A Technique for Border Molding Edentulous Impressions Using Vinyl Polysioxane Material
Authors: Chaffee Nancy R. , Cooper Lyndon F. , Felton David A.
Published: March 2005

A technique for making selective tissue placement final impressions for complete dentures using vinyl polysiloxane and custom trays with peripheral relief is presented. This technique is an alternative to the conventional method of border molding using modeling plastic impression compound.
Characterization of an immortalized oviduct cell line from the cynomolgus monkey (Macaca fascicularis)
Authors: Okada H. , Hirose Y. , Manonmani P. , Uda A. , Ito M. , Sankai T.
Published: March 2005

Abstract:  To establish reproductive biological techniques in mammals, it is important to understand the growth environment of the embryo. Oviduct epithelial cells are in close proximity to the embryo during pre‐implantation development. We, therefore, established an immortalized oviduct epithelial cell line from the cynomolgus monkey, evaluated the usefulness of these cells as feeder cells for embryo culture, and investigated the gene expression of several growth factors and cytokines in the cells. The immortalized cells were positive for the anti‐cytokeratin antibody, as determined by immunocytochemistry, indicating that they are epithelial. They also expressed oviductin, which is specific to oviduct epithelial cells, glyceraldehyde‐3‐phosphate dehydrogenase (control), leukemia inhibitory factor, vascular endothelial growth factor, epidermal growth factor, insulin‐like growth factor 1, transforming growth factor beta‐2, and interleukin 4. Mouse embryo development was improved when the immortalized cells were used as feeder cells. This cell line is also useful for studying the factors secreted by oviduct epithelial cells.
Enhanced Transcription of Contractile 5‐Hydroxytryptamine 2A Receptors via Extracellular Signal‐Regulated Kinase 1/2 after Organ Culture of Rat Mesenteric Artery
Authors: Cao Yong‐Xiao , He Lang‐Chong , Xu Cang‐Bao , Luo Guo‐Gang , Edvinsson Lars
Published: March 2005

Abstract: 5‐Hydroxytryptamine (5‐HT) has been found to elicit enhanced contractile effects in some vascular disorders. The present study was designed to examine if vascular 5‐HT2A receptors are up‐regulated during organ culture and if the extracellular signal‐regulated protein kinase 1/2 (ERK1/2) pathways are involved. Compared with fresh rat mesenteric artery ring segments, the contractile responses to 5‐HT were significantly increased in the segments cultured for 6, 24 or 48 hr (P<0.05, P<0.01, P<0.01, respectively). The 5‐HT‐induced contraction occurred via 5‐HT2A receptors, since the selective 5‐HT2A antagonist ketanserin blocked the 5‐HT‐induced contraction in the fresh segments with a pA2 value 9.5 (slope was 0.98 with 95% confidence intervals from 0.8 to 1.1). A similar result was obtained in the segments cultured for 24 hr with a pA2 value of 9.43 (slope=0.91 and 95% confidence intervals between 0.45 to 2.3). In addition, the enhanced 5‐HT2A receptor contraction occurred with a significant increase of 5‐HT2A receptor mRNA (P<0.05). Organ culture of the mesenteric artery was found to activate ERK1/2 already within 1 and 3 hr. It is likely that the ERK1/2 pathways were involved as a initial switch, since the selective ERK1/2 pathway inhibitor SB386023 abolished both up‐regulation of 5‐HT2A mRNA transcription and the enhanced contractile response to 5‐HT. These data reveal a role of ERK1/2 in up‐regulation of 5‐HT2A receptors and suggest a possibility to inhibit the enhanced responses to 5‐HT by inhibition of the ERK1/2 pathway.
A Review of Water Hammer Theory and Practice
Authors: Ghidaoui Mohamed S. , Zhao Ming , McInnis Duncan A. , Axworthy David H.
Published: March 2005

Hydraulic transients in closed conduits have been a subject of both theoretical study and intense practical interest for more than one hundred years. While straightforward in terms of the one-dimensional nature of pipe networks, the full description of transient fluid flows pose interesting problems in fluid dynamics. For example, the response of the turbulence structure and strength to transient waves in pipes and the loss of flow axisymmetry in pipes due to hydrodynamic instabilities are currently not understood. Yet, such understanding is important for modeling energy dissipation and water quality in transient pipe flows. This paper presents an overview of both historic developments and present day research and practice in the field of hydraulic transients. In particular, the paper discusses mass and momentum equations for one-dimensional Flows, wavespeed, numerical solutions for one-dimensional problems, wall shear stress models; two-dimensional mass and momentum equations, turbulence models, numerical solutions for two-dimensional problems, boundary conditions, transient analysis software, and future practical and research needs in water hammer. The presentation emphasizes the assumptions and restrictions involved in various governing equations so as to illuminate the range of applicability as well as the limitations of these equations. Understanding the limitations of current models is essential for (i) interpreting their results, (ii) judging the reliability of the data obtained from them, (iii) minimizing misuse of water-hammer models in both research and practice, and (iv) delineating the contribution of physical processes from the contribution of numerical artifacts to the results of waterhammer models. There are 134 refrences cited in this review article.
A Mathematical Model of Alveolar Gas Exchange in Partial Liquid Ventilation
Authors: Suresh Vinod , Anderson Joseph C. , Grotberg James B. , Hirschl Ronald B.
Published: March 2005

In partial liquid ventilation (PLV), perfluorocarbon (PFC) acts as a diffusion barrier to gas transport in the alveolar space since the diffusivities of oxygen and carbon dioxide in this medium are four orders of magnitude lower than in air. Therefore convection in the PFC layer resulting from the oscillatory motions of the alveolar sac during ventilation can significantly affect gas transport. For example, a typical value of the Pe´clet number in air ventilation is Pe∼0.01, whereas in PLV it is Pe∼20. To study the importance of convection, a single terminal alveolar sac is modeled as an oscillating spherical shell with gas, PFC, tissue and capillary blood compartments. Differential equations describing mass conservation within each compartment are derived and solved to obtain time periodic partial pressures. Significant partial pressure gradients in the PFC layer and partial pressure differences between the capillary and gas compartments PC-Pg are found to exist. Because Pe≫1, temporal phase differences are found to exist between PC-Pg and the ventilatory cycle that cannot be adequately described by existing non-convective models of gas exchange in PLV. The mass transfer rate is nearly constant throughout the breath when Pe≫1, but when Pe≪1 nearly 100% of the transport occurs during inspiration. A range of respiratory rates (RR), including those relevant to high frequency oscillation (HFO)+PLV, tidal volumes VT and perfusion rates are studied to determine the effect of heterogeneous distributions of ventilation and perfusion on gas exchange. The largest changes in PCO2 and PCCO2 occur at normal and low perfusion rates respectively as RR and VT are varied. At a given ventilation rate, a low RR-high VT combination results in higher PCO2, lower PCCO2 and lower PC-Pg than a high RR-low VT one.
Influence of Decorin and Biglycan on Mechanical Properties of Multiple Tendons in Knockout Mice
Authors: Robinson Paul S. , Huang Tung-Fu , Kazam Elan , Iozzo Renato V. , Birk David E. , Soslowsky Louis J.
Published: March 2005

Evaluations of tendon mechanical behavior based on biochemical and structural arrangement have implications for designing tendon specific treatment modalities or replacement strategies. In addition to the well studied type I collagen, other important constituents of tendon are the small proteoglycans (PGs). PGs have been shown to vary in concentration within differently loaded areas of tendon, implicating them in specific tendon function. This study measured the mechanical properties of multiple tendon tissues from normal mice and from mice with knock-outs of the PGs decorin or biglycan. Tail tendon fascicles, patellar tendons (PT), and flexor digitorum longus tendons (FDL), three tissues representing different in vivo loading environments, were characterized from the three groups of mice. It was hypothesized that the absence of decorin or biglycan would have individual effects on each type of tendon tissue. Surprisingly, no change in mechanical properties was observed for the tail tendon fascicles due to the PG knockouts. The loss of decorin affected the PT, causing an increase in modulus and stress relaxation, but had little effect on the FDL. Conversely, the loss of biglycan did not significantly affect the PT, but caused a reduction in both the maximum stress and modulus of the FDL. These results give mechanical support to previous biochemical data that tendons likely are uniquely tailored to their specific location and function. Variances such as those presented here need to be further characterized and taken into account when designing therapies or replacements for any one particular tendon.
‘‘Aristotelian’’ was given as the answer, but what was the question?
Authors: Lythcott Jean
Published: March 2005

Students come to physics instruction, in Newtonian mechanics, with naive ideas about how and why things move; for example, many believe that force causes motion and, conversely, that in the absence of a force things are necessarily at rest. Moreover, such preconceived ideas interfere with the ability of students to learn, and function within, the Newtonian paradigm. These student ideas have been labeled ‘‘Aristotelian,’’ a catchy label that has rapidly become widely accepted. This paper shows that these student beliefs are not like those of Aristotle, questions the hypothesis that generated the label, and describes a danger, to the sound growth of knowledge, inherent in the use of theory-ladened nomenclature. The purpose of the paper is to suggest that the label be abandoned so that this important line of research, with its profound implications for teachers, may develop unhindered by the weight of incorrect, theory-driven nomenclature.
Diagnosis and remediation of an alternative conception of velocity using a microcomputer program
Authors: Hewson Peter W.
Published: March 2005

This article describes a microcomputer program which was designed to diagnose students who use a position criterion for judging when two objects are moving with the same velocity, i.e., who say that when two objects are at the same position, their velocities are equal. Students who use this criterion are directed to the remedial part of the program which was designed in accord with a model of learning as conceptual change. The program has been used with more than 120 students at different educational levels. Results reported in this article show that the program has been effective in changing students’ alternative conceptions of velocity, i.e., as a result of using the program they were able to judge relative velocity correctly.
Pictet’s experiment: The apparent radiation and reflection of cold
Authors: Evans James , Popp Brian
Published: March 2005

Towards the end of the eighteenth century it was discovered by Marc-Auguste Pictet of Geneva that cold emanations from a flask of snow could be reflected and focused by mirrors in the same way as the emanations from a heated object. Pictet’s discovery had an invigorating effect on research on radiant heat. We sketch the scientific milieu in which Pictet worked, describe the line of investigation that led him to his discovery, and summarize the theoretical explanations offered by Pictet and his contemporaries for this and related experiments. A simple qualitative explanation in modern terms is offered for the apparent radiation and reflection of cold. Finally, detailed directions are provided for replicating the experiment as a demonstration for the lecture hall.
Available work from a finite source and sink: How effective is a Maxwell’s demon?
Authors: Leff Harvey S.
Published: March 2005

The maximum work obtainable from a finite heat source and finite heat sink, initially at respective temperatures T+ and T−, is determined as a function of the temperature ratio τ=T−/T+ and the heat capacities of the source and sink. The thermal efficiency with which this work is delivered is found to be well approximated by η*=1−τ1/2 for τ≥0.1, independent of the source and sink heat capacities. It is noted that η* occurs in other contexts for which work or power output is optimized, and is a surprisingly ‘‘universal’’ efficiency. A reversible polycycle that delivers the maximum work using an ideal gas working fluid is found to exist only if the heat capacity of the heat sink exceeds that of the working fluid. An example of a finite source/sink combination from which work can be generated is an enclosed gas, divided in half by a partition with a small, controllable trap door operated by a Maxwell’s demon. If the demon opens and closes the door selectively, so as to achieve a temperature difference across the partition, the analysis here enables an estimate of the subsequent maximum work that can be generated and the efficiency of this generation. Numerical estimates show that, as might be expected, such a demon is a rather ineffective work producer.