bluuebunny/crossref_metadata_2025 huggingface dataset:
The Quest for Quality: A Quality Adjusted Dynamic Regulatory Mechanism
Authors: De Fraja Gianni , Iozzi Alberto
Published: November 2008

In situations where quality is fixed, the widely used RPI‐X regulatory mechanism has a number of desirable properties, such as convergence to a second best optimum. Theoretical analysis of this mechanism in the case of endogenous quality is limited and therefore regulators have typically imposed constraints on the firm's quality choice in ad hoc manners, either by mandating quality levels, or by including quality adjustment factors in the RPI‐X mechanism. In this paper, we construct the rigorous theoretical counterpart of these manners of including quality measures in the constraints faced by a regulated firm. This mechanism converges to second best optimum. It works by offering the firm trade‐offs between prices and qualities based on the choice it made in the previous period; however, reflecting the practical problem valuing quality, the informational requirement to select these trade‐offs appropriately is qualitatively stronger than in the fixed quality case. Moreover, even when the informational problem can be overcome, we identify a further potential pitfall in the approach taken in practice by regulators, and show that, in order to avoid it, the regulated firm should be subject to an additional constraint, which we label the distance constraint, and which can be interpreted as requiring the firms to choose prices and qualities within a band in every period.
Influence of Matrix Type on Surface Roughness of Three Resins for Provisional Crowns and Fixed Partial Dentures
Authors: Ayuso‐Montero Raul , Martinez‐Gomis Jordi , Lujan‐Climent Mar , Salsench Juan , Peraire Maria
Published: November 2008

Purpose: This study evaluated the effect of matrix type on the surface roughness of resins for provisional crowns and fixed partial dentures.

Materials and Methods: Ninety specimens of two acrylic resins (Trim II, Tab2000) and one bis‐acryl composite (Protemp II Garant) were fabricated using one of three matrices: irreversible hydrocolloid (Cavex CA37), poly(vinyl siloxane) (Aquasil) or vacuum‐formed matrix (Bio‐flow Hard). The sample size for each resin‐matrix combination was 10. The vestibular face of one natural maxillary central incisor was used as a model to fabricate all the specimens, following the custom fabrication technique. The average roughness measurements, Ra (μm), were obtained using a profilometer, and the data were analyzed using Kruskal‐Wallis and Mann‐Whitney U‐tests. The results were contrasted against the surface roughness of the tooth using a one‐sample t‐test.

Results: Aquasil and vacuum‐formed matrix had a smoother surface than Cavex CA37 regardless of the resin tested (p < 0.05). Protemp II Garant had the smoothest surface regardless of the matrix used, with no significant differences when polymerized against the three different matrices. Trim II polymerized against Cavex CA37 had a rougher (p < 0.05) surface than Aquasil or vacuum‐formed matrix. Tab2000 had the smoothest surface (p < 0.05) when polymerized against a vacuum‐formed matrix.

Conclusions: There is no universal matrix that produces the smoothest surface: this depends on the compatibility between the resin and the matrix. Protemp II Garant polymerized against Cavex CA37 matrix yields a surface that is smooth enough not to require polishing unless this surface is adjusted.
Correlations between Color Differences Based on Three Color‐Difference Formulas Using Dental Shade Guide Tabs
Authors: Kim Jong‐Gil , Yu Bin , Lee Yong‐Keun
Published: November 2008

Purpose: The purpose of this study was to determine the correlation among color‐difference values based on three formulas between shade tab pairs from two shade guides [Vita Lumin (VITA) and Chromascop (CHRO)].

Materials and Methods: The color of shade tabs was measured relative to the standard illuminant D65 under the 8° standard observer function, and distributions for CIE L*, a*, and b* values were compared. One hundred and twenty shade pairs from VITA and 190 shade pairs from CHRO were used to calculate color differences using CIELAB, DIN99, and CIEDE2000 formulas (ΔE*ab, ΔE99, and ΔE00, respectively). A paired t‐test was used to determine the difference between each pair of the three color‐difference values (α= 0.01). Regression analysis was used to determine the correlations between the color differences (α= 0.01).

Results: For both shade guides, there were significant differences between ΔE*ab and ΔE00, ΔE*ab and ΔE99, and ΔE99 and ΔE00 (p < 0.01). ΔE*ab and ΔE00, and ΔE*ab and ΔE99 were strongly correlated (r2= 0.90 to 0.94, p < 0.05). Although a simplified a* rescaling function of the CIE a* axis has been added in the CIEDE2000 formula, the influence of the opposite signs in the a* value were found to be irrelevant to the ΔE00 value.

Conclusion:ΔE*ab,ΔE99, and ΔE00 can be used interchangeably for the evaluation of color difference of shade tabs.
Effects of Tooth Preparation Burs and Luting Cement Types on the Marginal Fit of Extracoronal Restorations
Authors: Ayad Mohamed F.
Published: November 2008

Purpose: Although surface roughness of axial walls could contribute to precision of a cast restoration, it is unclear how the roughness of tooth preparation affects marginal fit of the restoration in clinical practice. The purpose of this study was to describe the morphologic features of dentin surfaces prepared by common rotary instruments of similar shapes and to determine their effects on the marginal fit for complete cast crowns.

Materials and Methods: Ninety crowns were cast for standardized complete crown tooth preparations. Diamond, tungsten carbide finishing, and crosscut carbide burs of similar shape were used (N = 30). The crowns in each group were subdivided into three groups (n = 10) for use with different luting cements: zinc phosphate cement (Fleck's), glass ionomer cement (Ketac‐Cem), and adhesive resin cement (Panavia 21). Marginal fit was measured with a light microscope in a plane parallel to the tooth surface before and after cementation between four pairs of index indentations placed at equal distances around the circumference of each specimen. Difference among groups was tested for statistical significance with analysis of variance (ANOVA) followed by Ryan‐Einot‐Gabriel‐Welsch Multiple Range Test (α= 0.05).

Results: Analysis of measurements disclosed a statistically significant difference for burs used to finish tooth preparations (p < 0.001); however, luting cement measurements were not significantly different (p= 0.152). Also, the interaction effect was not significantly different (p= 0.685). For zinc phosphate cement, the highest marginal discrepancy value (100 ± 106 μm) was for tooth preparations refined with carbide burs, and the lowest discrepancy value (36 ± 30 μm) was for tooth preparations refined with finishing burs. For glass ionomer cement, the highest marginal discrepancy value (61 ± 47 μm) was for tooth preparations refined with carbide burs, and the lowest discrepancy value (33 ± 40 μm) was for tooth preparations refined with finishing burs. For adhesive resin cement, the highest marginal discrepancy value (88 ± 81 μm) was for tooth preparations refined with carbide burs, and the lowest discrepancy value (19 ± 17 μm) was for tooth preparations refined with finishing burs.

Conclusions: Marginal fit of complete cast crowns is influenced by tooth preparation surface characteristics, regardless of the type of luting agent used for cementation. Tooth preparations refined with finishing burs may favor the placement of restorations with the smallest marginal discrepancies, regardless of the type of cement used.
Dimensional Accuracy of an Epoxy Die Material Using Different Polymerization Methods
Authors: Prisco Rosario , Cozzolino Giancarlo , Vigolo Paolo
Published: November 2008

Purpose: Shrinkage of resinous die materials during setting reaction limits their acceptance, even though these materials show several advantages compared to stone die materials with respect to strength, abrasion resistance, and detail reproduction. The purpose of this study was to determine if retarding the setting reaction during polymerization and altering the base‐to‐catalyst ratio, as suggested by previous studies, can be recommended for resinous die materials to reduce the inaccuracy in transferring the spatial position of teeth or implants from the oral cavity to the master cast.

Materials and Methods: A Blue Star Type E epoxy resin die material was tested. A reference triangular metal master die was fabricated. Forty medium‐consistency polyether impressions of this model were made. Four groups (S, M, N, P) were compared, and ten dies were fabricated for each group. In the S group, the epoxy resin die material was manipulated according to the manufacturer's instructions; in the other three groups, the epoxy resin die material was manipulated by retarding the setting reaction and by modifying the epoxy resin base/activator ratio.

Results: One‐way ANOVA revealed significant differences between the four groups of the epoxy resin die material (p < 0.0001). Tukey's multiple comparisons test (p < 0.05) revealed that none of the resin groups was similar to the metal master die for each of the tested dimensions (A, B, and C). For the specific dimension C, however, the P group was statistically closer to the metal master die than the S group.

Conclusion: The epoxy resin die material tested in this research did not improve its dimensional accuracy following retarding polymerization or modifying the epoxy resin base/activator ratio. The epoxy resin material exhibited higher contraction variability across all tested groups. This shrinkage can significantly affect the dimension of the master cast.
Bertolotti's Syndrome: A Case Report
Authors: Mitra Raj , Carlisle Mark
Published: November 2008

Study Design:  A case report and literature review is presented.

Objective:  To review relevant data for the management of Bertolotti's syndrome and to determine whether the transverse process‐ilium articulation may be a pain generator.

Background:  Bertolotti's syndrome is associated with axial low back pain secondary to arthritic changes; the pain generator in the disorder is unclear.

Methods:  We present a case report of symptomatic Bertolotti's syndrome managed with intra‐articular steroid injections.

Results:  A patient with Bertolotti's syndrome had significant relief of axial pain after steroid injection of the ilium‐transverse process articulation.

Conclusions:  Steroid therapy may be a non‐surgical alternative for the treatment of symptomatic Bertolotti's syndrome.
Ten‐year quality control of a semiautomated procedure of cord blood unit volume reduction
Authors: Lecchi Lucilla , Perego Lucia , Garcea Filomena , Ratti Ilaria , Brasca Manuela , Dotti Deborah , Cimoni Silvia , Pezzali Ilaria , Celeste Teresa , Giovanelli Silvia , Butti Barbara , De Fazio Nicola , Lopa Raffaella , Rebulla Paolo
Published: November 2008

BACKGROUND: Volume reduction of cord blood units decreases the cost of cryogenic storage. This study reports the analysis of a 10‐year quality control program of a semiautomated cord blood volume reduction procedure.

STUDY DESIGN AND METHODS: Cord blood was collected in a plastic bag containing 29 mL citrate‐phosphate‐dextrose, centrifuged at 2124 × g for 12 minutes, and processed with a semiautomated device. The procedure was aimed at removing most red blood cells and plasma and concentrating hematopoietic progenitors in the buffy coat (BC), thus reducing the unit volume and saving cryogenic space. Finally, the BC was cryopreserved with an equal volume of 20 percent dimethyl sulfoxide. Total nucleated cells (TNCs) were counted before and after processing in the 4311 units banked from 1998 through 2007, whereas CD34+ cells and colony‐forming units–granulocyte‐macrophage (CFU‐GM) were counted in 420 random units from 2001 through 2007.

RESULTS: Mean postvolume reduction annual recoveries of TNCs, CD34+ cells, and CFU‐GM ranged from 82.8 ± 12.3 (standard deviation) to 91.4 ± 6.4 percent, from 87.8 ± 14.1 to 95.2 ± 23.8 percent, and from 101.5 ± 51.4 to 117.8 ± 59.5 percent, respectively. Very strong correlations were found (r > 0.87) between postprocessing versus preprocessing TNCs, CD34+ cells, and CFU‐GM; a moderate correlation between initial TNC count and unit's volume (r = 0.51); and no correlation between TNC percentage of recovery in the BC and initial unit's volume. The latter data indicate that most TNCs concentrate in the BC.

CONCLUSIONS: The semiautomated procedure of cord blood unit volume reduction used in this study provides high and stable cellular recoveries during several years of routine cord blood banking.
The persistence and evanescence of blood group alloantibodies in men
Authors: Tormey Christopher A. , Stack Gary
Published: November 2008

BACKGROUND: Non‐ABO blood group (BG) alloantibodies can disappear over time, confounding compatibility testing and predisposing patients to delayed hemolytic transfusion reactions. The goal of this study was to analyze BG antibody disappearance after transfusion‐related alloimmunization in men.

STUDY DESIGN AND METHODS: The transfusion service records of 18,750 military veterans at a Department of Veterans Affairs (VA) medical center were screened to identify male patients with one or more BG alloantibodies and who had at least one type and screen performed after initial antibody detection (n = 304). Antibodies were categorized as to whether they were present at a patient's first antibody screening test (“preexisting”) or after initial negative testing (“hospital‐acquired”).

RESULTS: Overall, the evanescence of hospital‐acquired antibodies (108/222; 48.6%) was significantly higher (p < 0.0001) than that of preexisting antibodies (36/185; 19.5%). Half (54/108) of evanescent, hospital‐acquired alloantibodies disappeared within 6 months of detection, and all disappeared by 10 years. Evanescence of hospital‐acquired antibodies was dependent on duration of follow‐up testing, because antibodies tested 5 or more years after initial development demonstrated the highest evanescence rate (35/55; 64%; p < 0.01). Some evanescent antibodies (9/407; 2.2% of total antibodies) disappeared and reappeared one or more times without known antigenic reexposure (“multiple evanescence”). Among commonly observed alloantibodies, disappearance varied with antigenic specificity.

CONCLUSIONS: Approximately two‐thirds of BG alloantibodies disappeared within 5 years of induction, a rate higher than previously reported in mixed‐sex populations. Evanescence did not appear to be a random, first‐order decay process, as evidenced by the lower evanescence rate of preexisting antibodies.
Robustness and U.S. Monetary Policy Experimentation
Authors: COGLEY TIMOTHY , COLACITO RICCARDO , HANSEN LARS PETER , SARGENT THOMAS J.
Published: November 2008

We study how a concern for robustness modifies a policymaker's incentive to experiment. A policymaker has a prior over two submodels of inflation‐unemployment dynamics. One submodel implies an exploitable trade‐off, the other does not. Bayes' law gives the policymaker an incentive to experiment. The policymaker fears that both submodels and his prior probability distribution over them are misspecified. We compute decision rules that are robust to misspecifications of each submodel and of the prior distribution over submodels. We compare robust rules to ones that Cogley, Colacito, and Sargent (2007) computed assuming that the models and the prior distribution are correctly specified. We explain how the policymaker's desires to protect against misspecifications of the submodels, on the one hand, and misspecifications of the prior over them, on the other, have different effects on the decision rule.
Monetary Aggregates and Liquidity in a Neo‐Wicksellian Framework
Authors: CANZONERI MATTHEW , CUMBY ROBERT , DIBA BEHZAD , LÓPEZ‐SALIDO DAVID
Published: November 2008

Woodford (2003) describes a popular class of neo‐Wicksellian (NW) models in which monetary policy is characterized by an interest rate rule, and the money market and financial institutions are typically not even modeled. Critics contend that these models are incomplete and unsuitable for monetary policy evaluation. Our banks and bonds (BB) model starts with a standard NW model and then adds banks and a role for bonds in the liquidity management of households and banks. The BB model gives a more complete description of the economy, but the NW model has the virtue of simplicity. Our purpose here is to see if the NW model gives a reasonably accurate account of macroeconomic behavior in the more complete BB model. We do this by comparing the models' second moments, variance decompositions, and impulse response functions. We also study the role of monetary aggregates and velocity in predicting inflation in the two models.
A Bayesian Random‐Effects Markov Model for Tumor Progression in Women with a Family History of Breast Cancer
Authors: Hui‐Min Wu Grace , Chang Shu‐Hui , Hsiu‐Hsi Chen Tony
Published: November 2008

Summary It makes intuitive sense to model the natural history of breast cancer, tumor progression from preclinical screen‐detectable phase (PCDP) to clinical disease, as a multistate process, but the multilevel structure of the available data, which generally comes from cluster (family)‐based service screening programs, makes the required parameter estimation intractable because there is a correlation between screening rounds in the same individual, and between subjects within clusters (families). There is also residual heterogeneity after adjusting for covariates. We therefore proposed a Bayesian hierarchical multistate Markov model with fixed and random effects and applied it to data from a high‐risk group (women with a family history of breast cancer) participating in a family‐based screening program for breast cancer. A total of 4867 women attended (representing 4464 families) and by the end of 2002, a total of 130 breast cancer cases were identified. Parameter estimation was carried out using Markov chain Monte Carlo (MCMC) simulation and the Bayesian software package WinBUGS. Models with and without random effects were considered. Our preferred model included a random‐effect term for the transition rate from preclinical to clinical disease (σ22f), which was estimated to be 0.50 (95% credible interval = 0.22–1.49). Failure to account for this random effect was shown to lead to bias. The incorporation of covariates into multistate models with random effect not only reduced residual heterogeneity but also improved the convergence of stationary distribution. Our proposed Bayesian hierarchical multistate model is a valuable tool for estimating the rate of transitions between disease states in the natural history of breast cancer (and possibly other conditions). Unlike existing models, it can cope with the correlation structure of multilevel screening data, covariates, and residual (unexplained) variation.
Asymptotic Distribution of Score Statistics for Spatial Cluster Detection with Censored Data
Authors: Commenges Daniel , Liquet Benoit
Published: November 2008

Summary Cook, Gold, and Li (2007, Biometrics 63, 540–549) extended the Kulldorff (1997, Communications in Statistics 26, 1481–1496) scan statistic for spatial cluster detection to survival‐type observations. Their approach was based on the score statistic and they proposed a permutation distribution for the maximum of score tests. The score statistic makes it possible to apply the scan statistic idea to models including explanatory variables. However, we show that the permutation distribution requires strong assumptions of independence between potential cluster and both censoring and explanatory variables. In contrast, we present an approach using the asymptotic distribution of the maximum of score statistics in a manner not requiring these assumptions.
Withdrawal From Coparenting Interactions During Early Infancy
Authors: ELLISTON DONNA , McHALE JAMES , TALBOT JEAN , PARMLEY MEAGAN , KUERSTEN‐HOGAN REGINA
Published: November 2008

This study examines early withdrawal in the coparenting system, and the utility of a brief problem‐solving discussion about coparenting responsibilities as a means for evaluating such withdrawal. One hundred and fifteen couples were evaluated both prenatally and at 3 months postpartum. During prenatal assessments, parents rated their personalities and completed marital assessments. After the baby arrived, they completed a negotiation task in which they discussed disputes about parenting roles and responsibilities, and interacted together with the baby in a triadic play assessment. Fathers' but not mothers' withdrawal during coparenting negotiations was associated with greater disengagement and less warmth during triadic play and with fathers' feelings that mothers did not respect their parenting. Fathers' but not mothers' withdrawal during coparenting negotiations was also forecast by low ego resilience and by an increase in depressive symptomatology during the postpartum. As the negotiation task appeared to be an effective provocateur of withdrawal when confronting coparenting disagreement, it may prove useful for eliciting this aspect of coparental process in work with couples.
Parent Characteristics as Antecedents of Maternal Gatekeeping and Fathering Behavior
Authors: CANNON ELIZABETH A. , SCHOPPE‐SULLIVAN SARAH J. , MANGELSDORF SARAH C. , BROWN GEOFFREY L. , SZEWCZYK SOKOLOWSKI MARGARET
Published: November 2008

The present study examined the role of prebirth parent characteristics as predictors of maternal gatekeeping (mothers' attempts to encourage or discourage fathers' interaction with their infant) and fathering behavior. Parents' idealization of their relationships within their families of origin, beliefs about the roles of fathers, and personality attributes (negative emotionality and communion) were assessed before their infant's birth. At 3.5 months postpartum, maternal gatekeeping behaviors (negative control, facilitation) and fathers' involvement and competence with their infants were assessed during observation of triadic play and child care. Results suggest reciprocal relations between maternal gatekeeping and fathering behavior. Furthermore, greater paternal communion was associated with greater paternal competence during play, whereas greater maternal communion was associated with lower paternal competence during child care. Greater maternal communion and greater maternal idealization related to fathers' lower relative involvement during play. As for maternal gatekeeping behavior, high negative emotionality in 1 parent was only accompanied by high levels of inhibitory maternal gatekeeping when the other parent had less progressive beliefs about the father's role. The implications of these findings for clinicians and practitioners are discussed.
Individual Resiliency Factors from a Genetic Perspective: Results from a Twin Study
Authors: HANSSON KJELL , CEDERBLAD MARIANNE , LICHTENSTEIN PAUL , REISS DAVID , PEDERSEN NANCY , BELDERHISER JENAE , ELTHAMMAR OLLE
Published: November 2008

This article is part of the Twin Mother's Study, a study that examines influences on maternal adjustment. A number of studies have investigated the importance of genetic factors for mental health, but few of these examine how genes and the environment influence resiliency/salutogenic factors. This article investigates the relative importance of genetic and environmental influences on resiliency/salutogenic factors. This study includes 326 twin pairs (150 monozygotic and 176 dizygotic) who are mothers, who are living with their spouse, and who are part of the Swedish twin register. Using self‐report structured questionnaires, we assessed salutogenic factors, depression, and quality of life; however, we analyzed the questionnaires completed by the mothers. Statistical analyses were conducted using structural equation modeling. We conclude that nonshared environmental components were of principal importance in individual resiliency/salutogenic factors in a genetically informative design, but we also noted that genetic influences were important. The shared environment had mainly no effect.
Family Secrets and Family Functioning: The Case of Donor Assistance
Authors: BERGER RONI , PAUL MARILYN
Published: November 2008

The purpose of this study was to examine the relationship between adult offspring's perception of family functioning and of parental use of topic avoidance to maintain secrecy regarding the use of donor assistance to conceive. A cross‐sectional design was used to study a convenience sample of 69 young adult donor offspring who completed a demographic questionnaire, a topic avoidance scale relative to each of their rearing parents, and the Beavers Self Report Family Instrument. Findings indicated that participants perceived both parents as avoiding the topic of donor assistance more than other topics, mothers as avoiding all topics less than fathers, and topic avoidance was negatively associated with family functioning. Mothers' general topic avoidance was the strongest predictor of family functioning. Parents' disclosing together was predictive of higher family functioning. Implications for practice and future research are suggested.
Subsolidus Phase Relationships in the ZnO–In2O3–SnO2 System
Authors: Harvey Steven P. , Poeppelmeier Kenneth R. , Mason Thomas O.
Published: November 2008

The subsolidus phase relationships in the ZnO–InO1.5–SnO2 system were investigated at 1275°C using X‐ray diffraction. Each of the end members of the ternary diagram is a transparent conducting oxide. There are two substantial solid solutions in the ternary phase space, the bixbyite solid solution In2−2xZnxSnxO3 (x=0–0.40), and the indium substituted zinc stannate spinel, Zn(2−x)Sn(1−x)In2xO4 (x=0–0.45). The bixbyite solid solution is an outstanding TCO, whereas the spinel is only moderately conducting. Along the ZnO–InO1.5 binary, there is a series of transparent conducting homologous compounds (ZnO)k·In2O3 (where k=3, 4, 5, 6, 7, 9, 11). Within ternary phase space, these homologous compounds were found to exhibit negligible Sn solubility, and were always found to be compatible with the spinel. Equilibrium was difficult to achieve in the phase space between the homologous series compounds and the spinel, owing to sluggish kinetics. A procedure involving mixtures of prereacted spinel and the Zn11In2O14 (k=11) compound was developed, which allowed for more rapid approach to thermodynamic equilibrium, thereby allowing for the establishment of phase relationships near the ZnO corner of the phase diagram.
Mechanism of Formation of TiO2‐Doped Mullites from Heated Single‐Phase Gels Investigated by Structural and Microstructural Parameters
Authors: Serrano Francisco Javier , De Sola Esther Ruiz , Kojdecki Marek Andrzej , Amigó José María , Alarcón Javier
Published: November 2008

An analysis of the microstructure of TiO2‐doped mullites prepared from monophasic gels thermally treated in the temperature range 900°–1600°C is reported. Two series of gels with nominal compositions 3(Al2−xTixO3)·2(SiO2) and 2(Al2−xTixO3)·(SiO2), in the range 0≤x≤0.15, were prepared. X‐ray powder diffraction (XRD) and scanning electron microscopy (SEM) were used to follow the structural and textural evolution from gels to the final doped mullites. The crystallite sizes and microstrains were determined by linewidth refinements of XRD patterns using the integral breadth method of Langford and the Warren–Averbach analysis. XRD patterns showed the formation of Al2TiO5 and/or rutile as minor impurities in both series of mullites for compositions x=0.10 and 0.15 at temperatures between 1200° and 1600°C. Larger mullite crystallite sizes were produced by increasing either the content of dissolved titanium oxide or the temperature. In general, crystallite sizes are larger in the titanium oxide‐doped alumina‐rich mullite series while the crystallite aspect ratio values are similar in both series of doped mullites. In mullites produced at lower temperatures, the sizes of nanocrystals estimated by SEM were in agreement with those obtained by line broadening analysis.

A mechanism of formation of TiO2‐doped mullite solid solutions is suggested on the basis of the interpretation of the structural and microstructural evolution from gels to doped mullites.
Dynamic Compressive Failure of AlON Under Controlled Planar Confinement
Authors: Paliwal Bhasker , Ramesh Kaliat T. , McCauley James W. , Chen Mingwei
Published: November 2008

An experimental technique is developed to impose a planar lateral confinement in a prismatic specimen (with a rectangular cross section); the setup enabled a controlled and homogeneous stress state with high lateral compressive stresses. A transparent polycrystalline aluminum oxynitride (AlON) specimen was used for the study. The statically precompressed specimen was then subjected to axial dynamic compressive loading using a modified compression Kolsky bar setup. Experimental design was performed using 3D computational modeling. Initial exploratory experiments were conducted on AlON at an average planar confinement of 400–410 MPa; the results suggested a higher compressive strength and a nonlinear stress evolution in AlON due to the confinement. A high‐speed camera was used to observe the damage evolution in the specimen during the course of loading. The photographs and stress evolution are suggestive of an additional inelastic deformation mechanism, whose evolution is slower than the typical brittle‐cracking type of damage apparent in the unconfined case. The TEM and high‐resolution electron microscope analysis indicated dislocation plasticity in some fragments; dislocations in the slip bands were characterized to be dissociated 〈110〉 dislocations on {111} planes. The width between two partial dislocations was about 15 nm, suggesting low stacking fault energy of AlON. Microscopic characterization also shows that the eventual fragmentation of AlON is by cleavage mainly along low‐index {111} planes.
Synthesis of a Li‐ and Ta‐Modified (K,Na)NbO3 Solid Solution by Mechanochemical Activation
Authors: Rojac Tadej , Benčan Andreja , Uršič Hana , Malič Barbara , Kosec Marija
Published: November 2008

The synthesis of (K0.485Na0.485Li0.03)(Nb0.8Ta0.2)O3 from a mechanochemically activated powder is presented for the first time. Mechanochemical activation, followed by a single calcination step was found to be a powerful technique for synthesizing a homogeneous solid solution with a low amount of contaminant, coming from the milling equipment, and good electrical properties without the need for a multiple calcination procedure involving intermediate wet‐milling steps, which are typically required in the conventional solid‐state synthesis route.
Effects of Milling and Calcination Temperature on the Compressibility and Sinterability of a Nanocrystalline Al2O3–Y3Al5O12 Composite Powder
Authors: Hassanzadeh‐Tabrizi Sayed Ali , Taheri‐Nassaj Ehsan
Published: November 2008

In the present work, the effects of milling and calcination temperature on the compressibility and sinterability of a nanocrystalline Al2O3–Y3Al5O12 composite powder prepared by an aqueous sol–gel method were investigated. The results showed that calcination temperature has a strong influence on the sinterability and final microstructure of amorphous powders. The lower calcination temperatures below 800°C resulted in the reduction of density and formation of a vermicular microstructure after sintering. It was also found that breaking of hard agglomerates into particles and smaller agglomerates after 1 h of milling leads to an increase in green density at the early stage of compaction when the rearrangement of particles is the dominant mechanism of the densification. The best‐performing sample was that calcined at 800°C and milled for 1 h, which yielded a relative density of 95% with a micronic/sub‐micronic microstructure after sintering at 1500°C.
Development of Dense Filler‐Free Polymer‐Derived SiOC Ceramics by Field‐Assisted Sintering
Authors: Esfehanian Mohammad , Oberacker Rainer , Fett Theo , Hoffmann Michael J.
Published: November 2008

Large samples of dense polymer‐derived ceramics in an Si–O–C system were prepared without using any filler particles or catalysts. For this purpose a commercial polymethylsilsesquioxane powder was first pyrolyzed at 900°C and then rapidly hot‐pressed at temperatures between 1400° and 1600°C. Density, hardness, and flexural strength of the samples were measured as a function of hot‐pressing temperature. No carbothermic reaction between SiO2and C was observed, but nanocrystals of β‐SiC were found in all the samples referring to a phase separation of the originally amorphous microstructure.
Lanthanum‐ and Oxygen‐Deficient Crystal Structures of Oxide–Ion Conducting Apatite‐Type Silicates
Authors: Iwata Tomoyuki , Béchade Emilie , Fukuda Koichiro , Masson Olivier , Julien Isabelle , Champion Eric , Thomas Philippe
Published: November 2008

The structural change of La9.33−2x(SiO4)6O2−3x with increasing x value was investigated by means of laboratory X‐ray powder diffraction (CuKα1). Crystal structures of the three types of specimens with x=0, 0.06, and 0.085 were refined by the Rietveld method, with the anisotropic displacement (U) parameters being assigned for all atoms. Each crystal structure was composed of three types of polyhedra: La1O9, La2O7, and SiO4. With increasing x value, the occupancies (g) of both La1 and La2 sites decreased steadily. The La vacancies were charge balanced by the deficiency of the mobile O atoms that were not covalently bonded to Si atoms. The polyhedral volume of La2O7 decreased steadily about 0.7% with a decrease of the g(La2) value from 0.995 to 0.982. On the other hand, the polyhedral volume of La1O9 showed an increase of about 1.0% with a decrease of the g(La1) value from 0.841 to 0.818. The marked difference in deformation behavior of the two types of polyhedra could be attributable to the distinction in site occupancies between La1 [g(La1)<0.85] and La2 [g(La2)>0.98]. For the mobile O atoms, the displacement magnitudes, being evaluated from the U parameters, decreased steadily with increasing x value. The positional disordering of these atoms might be related to their mobilities at high temperatures.
Micro‐Indentation‐Induced Domain Switching in Tetragonal Barium Titanate
Authors: Cheng Shun‐Yu , Ho New‐Jin , Lu Hong‐Yang
Published: November 2008

Pressureless‐sintered BaTiO3ceramics containing ferroelectric domains are subjected to Vickers microindentation at room temperature. Domain switching along indentation cracks is investigated using electron backscatter diffraction (EBSD) in a scanning electron microscope. Crystallographic orientation relationships between neighboring domains in the vicinity of indentation cracks are determined unambiguously and domain switching is confirmed at the sites. The polarc‐axis of both the 90° and 180° domains is reoriented by 90° when the applied compressive stress along the polar direction by microindentation exceeds the coercive stress, and triggers ferroelastic switching. The switching zone of ∼10 μm in the crack wake is estimated from the switched regions. A microtexture along the (001) plane revealed by X‐ray diffractometry and induced by domain switching in the crack wake is confirmed by EBSD diffraction.
Misfit Dislocation Formation at the c/t Interphase Boundary in Y‐TZP
Authors: Ii Seiichiro , Yoshida Hidehiro , Matsui Koji , Ikuhara Yuichi
Published: November 2008

The interphase boundary between the front of a cubic and tetragonal matrix grown in a yttria‐stabilized tetragonal zirconia polycrystal was investigated by conventional transmission electron microscopy (CTEM) and high‐resolution transmission electron microscopy (HRTEM). Periodic contrasts with a regular spacing were clearly observed on the boundary. CTEM and HRTEM observation revealed that there are misfit dislocations with a Burgers vector of 1/2〈110〉. The yttrium cation distribution across the interphase boundary was measured by energy‐dispersive X‐ray spectroscopy using a probe size <1 nm. The yttrium cation content changes sharply at the c/t interphase boundary with a transition width of about 10 nm.
Preceramic Paper‐Derived Ceramics
Authors: Travitzky Nahum , Windsheimer Hans , Fey Tobias , Greil Peter
Published: November 2008

A novel class of preceramic paper may serve as a preform to manufacture lightweight as well as multilayer ceramic products. In this article, we discuss the formation, microstructure, and properties of preceramic papers and their conversion into ceramic materials. Oxide as well nonoxide ceramics were processed into single‐sheet, corrugated structures, and multilayer ceramics. A high filler loading and uniform distribution of ceramic fillers involves control of colloidal surface interaction including electrostatic, electrosteric, and mechanical retention. Sintering of an oxide‐loaded preceramic paper in air results in highly porous products, with the porosity shape and distribution templated by the pulp fiber used in papermaking. In the case of carbide‐loaded paper, dense composite materials are obtained by reactive infiltration processing. Anisotropic properties of machine‐fabricated preceramic paper and bonding interfaces in multilayer stacks give rise to anisotropic mechanical properties of the resulting ceramic composites. Noncatastrophic failure was observed when tensile loading stress was applied parallel to the interfaces (in‐plane loading). Applying well‐established paper processing technologies, including laminated object manufacturing, ceramic structures of complex shape and size can easily be processed, offering a high potential for economical manufacturing.
Photoluminescence of High‐Aspect‐Ratio PbTiO3 Nanotube Arrays
Authors: Yang Yang , Wang Xiaohui , Sun Changku , Li Longtu
Published: November 2008

High‐aspect‐ratio PbTiO3 nanotube arrays have been synthesized by the hydrothermal method. X‐ray diffraction result shows that PbTiO3 nanotube arrays have a tetragonal perovskite structure without any other impurity. The photoluminescence property of PbTiO3 nanotube arrays studied at room temperature reveals a strong green emission band peaking at 550 nm (2.25 eV). Both Raman spectroscopy and X‐ray photoelectron spectroscopy demonstrate the existence of local defects in PbTiO3 nanotube arrays, which act as emission source and result in the photoluminescence behavior of PbTiO3 nanotube arrays.
Firearm Deaths by Law Enforcement
Authors: Gill James R. , Pasquale‐Styles Melissa
Published: November 2008

Abstract:  The use of deadly force during law enforcement is a matter that compels public scrutiny. There were 42 gunshot deaths caused by police over a 4‐year period in New York City. The decedents’ average age was 31 years and ranged from 17 to 64 years. There were 41 males and one female; and 26 Black, nine Hispanic, and seven White decedents. Ethanol and/or drugs of abuse were detected in 78% (31/40) of the decedents. The vast majority of shootings occurred with the police responding to a crime and 90% of the decedents were armed (26 handguns, six knives, one axe, one metal pipe, and one toy gun). Vehicles were used as weapons in two incidents. A total of 177 bullets struck the 42 decedents. Fourteen decedents sustained single gunshot wounds (GSWs), and the remainder had multiple GSWs ranging from 2 to 21. In the majority of the cases in this study, the number of GSWs of the body was three or fewer. Thirteen decedents had at least one GSW of the back or buttocks, accounting for 25 of the total 177 wounds, and four of the 13 had GSWs of only the back. With the exception of the upper extremities, GSWs of all locations were more likely to penetrate than perforate. Although these deaths may be high profile, the certification is typically straightforward and the cause (i.e., GSW) and manner of death (homicide) are readily apparent. Although police shootings in which the decedent was unarmed and/or sustained numerous GSWs are widely reported by the lay press, these types of shootings were not typical in our study.
Extensive Petechiae in Attempted Self‐Strangulation
Authors: Lambe Andrea , Püschel Klaus , Anders Sven
Published: November 2008

Abstract:  A 29‐year‐old Korean man reported to have been robbed, bound, and gagged by a stranger in his apartment. Clinical findings included extensive petechiae to his face and tramline patterned abrasions and ligature furrows to his neck and face as well as his wrists. Initially, no other leads in the investigation existed and a robbery was assumed to have taken place. The man eventually confessed to fabricating the story and to having self‐induced the ligature marks by subluxating his jaw at the temporomandibular joint and hooking the rope closest to the back of his neck on the corner of table. The man demonstrated this unsuspected ability to law enforcement officers. As a motive for his unconventional behavior, he confessed to engaging in autoaggressive behavior as punishment for “losing face” after his ex‐girlfriend terminated her pregnancy. This case demonstrates that petechiae due to neck compression also may occur in the living and are due to vascular compression and not lethal hypoxia.
Agonal Sequences in Four Filmed Hangings: Analysis of Respiratory and Movement Responses to Asphyxia by Hanging*
Authors: Sauvageau Anny
Published: November 2008

Abstract:  The human pathophysiology of asphyxia by hanging is still poorly understood, despite great advances in forensic science. In that context, filmed hangings may hold the key to answer questions regarding the sequence of events leading to death in human asphyxia. Four filmed hangings were analyzed. Rapid loss of consciousness was observed between 13 sec and 18 sec after onset of hanging, closely followed by convulsions (at 14–19 sec). A complex pattern of decerebration rigidity (19–21 sec in most cases), followed by a quick phase of decortication rigidity (1 min 00 sec–1 min 08 sec in most cases), an extended phase of decortication rigidity (1 min 04 sec–1 min 32 sec) and loss of muscle tone (1 min 38 sec–2 min 47 sec) was revealed. Very deep respiratory attempts started between 20 and 22 sec, the last respiratory attempt being detected between 2 min 00 sec and 2 min 04 sec. Despite differences in the types of hanging, this unique study reveals similarities that are further discussed.
Omega‐3 Fatty Acids and the Cardiometabolic Syndrome
Authors: Juturu Vijaya
Published: November 2008

Benefits of fish consumption in patients with the cardiometabolic syndrome relate to the high biologic value of protein, omega‐3 fatty acids, as well as certain minerals and vitamins in fish. Recently, the American Heart Association issued new guidelines for the intake of omega‐3 oils for the prevention of coronary heart disease. The objective of this paper is to evaluate the potential health benefits of fish consumption and/or fish oil supplements in reducing cardiometabolic syndrome risk factors. The consumption of fish or fish oil containing omega‐3 polyunsaturated fatty acids reduces the risk of coronary heart disease, decreases triglyceride, blood pressure, and inflammatory markers, improves endothelial function, prevents certain cardiac arrhythmias, reduces platelet aggregation (including reactivity and adhesion), reduces vasoconstriction, enhances fibrinolysis, reduces fibrin formation, and decreases the risk of microalbuminuria and sudden cardiac death. Thus, fish intake or fish oil supplement use is beneficial to reduce cardiometabolic risk factors.
Demographic Analyses of the Effects of Carvedilol vs Metoprolol on Glycemic Control and Insulin Sensitivity in Patients With Type 2 Diabetes and Hypertension in the Glycemic Effects in Diabetes Mellitus: Carvedilol‐Metoprolol Comparison in Hypertensives (GEMINI) Study
Authors: Phillips Robert A. , Fonseca Vivian , Katholi Richard E. , McGill Janet B. , Messerli Franz H. , Bell David S.H. , Raskin Philip , Wright Jr Jackson T. , Iyengar Malini , Anderson Karen M. , Lukas Mary Ann , Bakris George L. ,   for the GEMINI Investigators
Published: November 2008

In the Glycemic Effects in Diabetes Mellitus: Carvedilol‐Metoprolol Comparison in Hypertensives (GEMINI) trial, carvedilol added to angiotensin‐converting enzyme inhibitors and angiotensin receptor blockers had neutral or beneficial effects on glycemic measures compared with metoprolol tartrate. For the 1235 diabetic hypertensive GEMINI patients, the authors assessed treatment differences by race (white/black/other), age (continuous variable), and sex on hemoglobin A1c, insulin resistance (homeostasis model assessment–insulin resistance [HOMA‐IR]), and blood pressure. Both treatments significantly reduced blood pressure in all subgroups, but the metabolic effects of carvedilol were more beneficial in subgroups of race and sex. Carvedilol did not affect hemoglobin A1c but improved HOMA‐IR results in all subgroups, significantly in males and “other race” subgroups. Metoprolol significantly increased hemoglobin A1c in all subgroups except “other race,” with no effect on HOMA‐IR findings. Differences vs metoprolol significantly favored carvedilol for hemoglobin A1c in white and female subgroups and favored carvedilol for HOMA‐IR in black, “other race,” and male subgroups. Carvedilol effects were favorable to adjustment of age as a covariate. In hypertensive patients with diabetes, carvedilol may be a more appropriate choice when β‐blockade is indicated.
The Insulin Gradient Phenomenon: A Manifestation of the Effects of Body Weight on Blood Pressure and Insulin Resistance
Authors: Aristizabal Dagnovar , Gallo Jaime , Fernández Ricardo , Restrepo Maria A. , Zapata Nora , Correa Monica
Published: November 2008

The relationship between hyperinsulinemia and hypertension is frequently observed in overweight patients; however, population studies have not confirmed an independent association. A population study was conducted to assess whether differences in body mass index and levels of insulinemia modify cardiovascular hemodynamics and arterial pressure. In all, 322 healthy adults underwent a medical evaluation including insulin sensitivity and cardiac performance assessment with echocardiography. A direct relationship between body mass index and blood pressure (r=0.36; P<.01) was shown along with increments in fasting insulin levels. The underlying and progressive rise in insulin levels during blood pressure increase is named the insulin gradient. Left ventricular systolic indexes were significantly greater in the higher‐insulin quartile. These findings suggest that body weight increases accompany a rise in systolic pressure and a drop in insulin sensitivity related to the insulin gradient. Increments in ejection fraction and cardiac output with normal total peripheral resistance are related to the blood pressure shift in these persons.
Surgical Treatment of the Cardiometabolic Syndrome and Obesity
Authors: Khan Khurshid Ahmad , Sowers James R.
Published: November 2008

Prevalence of overweight and obesity has reached a pandemic proportion worldwide and is increasingly contributing to premature morbidity and mortality. Lifestyle changes including behavioral modification, exercise, different dietary plans, and medications have very poor outcome on long‐term weight loss. Bariatric surgery has shown to be very effective for morbidly obese patients. Surgery in these patients not only decreases their body weight but also may improve comorbid conditions associated with obesity. These patients on average lose 61% of excess body weight depending on the procedure performed. Diabetes, hyperlipidemia, and hypertension are normalized in these patients by 77%, 70%, and 62%, respectively. Patients need to be selected carefully for surgical treatment of obesity and have to be monitored closely over the long term for nutritional deficiencies and other complications.