bluuebunny/crossref_metadata_2025 huggingface dataset:
Re‐generating the ‘self’ in learning: developing a culture of supportive learning in practice
Authors: Wilson Valerie , McCormack Brendan , Ives Glenice
Published: April 2006

This article presents the findings of a project that focused on developing a culture of learning where practitioners were able to engage in supported work‐based learning in a Special Care Nursery (SCN). The project was part of a larger study focusing on the implementation and evaluation of an emancipatory practice development programme in an SCN. The aim of this phase of the study was to gain an in‐depth understanding of how the implementation of practice‐development strategies could enable the creation of a culture of supportive learning in practice. The methodological and philosophical structure of the study was based on emancipatory practice development (ePD). The ePD strategies used are aimed at promoting the empowerment of nursing staff, utilizing staff knowledge and expertise to identify the need for change, encouraging reflection on and in practice, incorporating the views of service users in the change process, and supporting staff to challenge themselves and each other. Questions are framed to evaluate systematically the processes and outcomes of the study with a view to identifying changes in the learning culture that may have occurred as a result of PD strategies. Pre‐intervention findings highlighted that tensions existed between what people espoused about learning and what actually occurred in practice. Through the use of PD processes, participants in the study began to focus on the learning environment. Key themes identified in the data included ‘learning about learning’, ‘movement from subservience to partnership’, movement from rituals to reflective questions’ and ‘movement from self‐immersed to working with one another’. Taking self‐responsibility for learning and ‘regenerating the self’ in learning emerged as key issues underpinning these themes and are subthemes of ‘values and beliefs about learning’. It is argued that developing ‘responsible self’ is key to the creation of a culture of learning where practitioners are able to develop mutually supportive relationships in order to learn in and from their practice. In conclusion, learning culture has a significant impact on how nurses go about their everyday practice. The implementation of PD processes enabled a cultural shift to occur. As a result of this, a supportive learning culture embedded within the workplace emerged. Learning about learning was seen as an important part of the context that enabled the development of the responsible self.
Breaking Old Habits: Recent Research on Women, Spirituality, and the Arts in the Middle Ages1
Authors: Mecham June L.
Published: April 2006

The study of women, spirituality, and the arts has progressed considerably over the past twenty‐five years, becoming both more nuanced and sophisticated as well as more conflicted. Recent scholarship on this subject reflects the adoption of broader definitions of the arts and of female religiosity in addition to a weakening of both conceptual and disciplinary boundaries. Current research further demonstrates a greater democratization in the types of women and pious activities studied. Researchers are increasingly re‐conceptualizing piety in terms of grouped or interrelated actions tied to the visual and material culture of medieval Christianity, thereby highlighting the importance of performance within female devotion. While issues of essentialism and agency continue to stimulate debate, researchers have uncovered considerable evidence of the influence medieval women exerted upon religious drama, music, art, literature, and theology. Nevertheless, substantial areas for further research remain.
Forced Labor in Colonial West Africa
Authors: Ash Catherine B.
Published: April 2006

During the colonial period in West Africa, European officials and businessmen faced a perennial shortage of labor; their response was to rely on coercion. Despite their rhetoric of “free wage labor,” colonial officials thought Africans needed encouragement to understand time and work discipline. Africans continually resisted, making forced labor inefficient and costly. West Africans incorporated the European rhetoric of the abolition of slavery, free wage labor and workers’ benefits into their protests against colonial labor practices. By the late 1940s, most forms of forced labor had been abolished.
Women, Gender, and Rulership in Romance Europe: The Iberian Case
Authors: Shadis Miriam
Published: April 2006

This essay outlines some main themes of gender and rulership in Iberian history from the early twelfth through the fifteenth centuries. Focusing mainly on queens, the essay also addresses the experience of other elite women and men, looking at the nexus of gender ideology and the practical requirements of monarchy.
Fenofibrate, a peroxisome proliferator‐activated receptor α agonist, reduces hepatic steatosis and lipid peroxidation in fatty liver Shionogi mice with hereditary fatty liver
Authors: Harano Yuichi , Yasui Kohichiroh , Toyama Tetsuya , Nakajima Tomoki , Mitsuyoshi Hironori , Mimani Masahito , Hirasawa Tsutomu , Itoh Yoshito , Okanoue Takeshi
Published: April 2006

Abstract: Background and aims: The fatty liver Shionogi (FLS) mouse, a unique model for nonalcoholic fatty liver disease (NAFLD), is an inbred strain that develops spontaneous hepatic steatosis without obesity or diabetes mellitus. Peroxisome proliferator‐activated receptor (PPAR) α controls fatty acid metabolism. In the present study, we investigated the effect of fenofibrate, a PPARα agonist, on hepatic steatosis in FLS mice.

Methods: Thirteen‐week‐old FLS mice were fed a diet with 0.1% fenofibrate (w/w) for 12 days. The degree of hepatic steatosis was estimated by histological examination and hepatic triglyceride levels. Expression levels of genes involved in fatty acid turnover, including Acox1, Cpt1a, Fabp1, Acadl, and Acadm, were determined by Northern blot analyses. We measured levels of lipid peroxidation, glutathione, and anti‐oxidative enzymes, such as superoxide dismutase, catalase, and glutathione peroxidase, in the liver.

Result: Treatment of FLS mice with fenofibrate improved hepatic steatosis by activating expression of genes involved in fatty acid turnover and decreased hepatic lipid peroxidation. Fenofibrate increased the activity of catalase by upregulating its mRNA levels.

Conclusion: Fenofibrate, which is currently used in therapy of hyperlipidemia, might also be useful for treating patients with NAFLD even in cases where NAFLD is not associated with obesity or diabetes mellitus.
Ex vivo analysis of antineoplastic agents in precision‐cut tissue slices of human origin: effects of cyclooxygenase‐2 inhibition in hepatocellular carcinoma
Authors: Kern Michael A. , Haugg Anke M. , Eiteneuer Eva , Konze Elisabeth , Drebber Uta , Dienes Hans P. , Breuhahn Kai , Schirmacher Peter , Kasper Hans U.
Published: April 2006

Abstract: Cultures of precision‐cut tissue slices allow the investigation of substance effects on human tissues under in vivo‐like conditions over a limited time span. We have adapted the model for direct analyses of antineoplastic substances on tumor tissues. We have recently demonstrated that selective cyclooxygenase‐2 (COX‐2) inhibitors strongly suppress growth of human hepatocellular carcinoma (HCC) cells in vitro and nude mouse HCC implants by inducing apoptosis and reducing proliferation. We have now analyzed the effects of COX‐2 inhibition on human tumor tissue. Three hundred micrometer slices of tumorous and non‐tumorous liver tissue from three surgically resected HCCs were cultured with increasing concentrations of the selective COX‐2 inhibitor Meloxicam (20–200 μM) for 6, 12, 24, and 48 h. The cultured tissue slices were analysed morphologically and by immunohistology for proliferation (Ki‐67), apoptosis (M30), and COX‐2 expression. COX‐2 was expressed in all HCCs and in the non‐tumorous liver tissue. Cytoplasmic COX‐2 immunoreactivity in HCCs increased during culturing time. In two of three cases, COX‐2 inhibition significantly increased tumor cell apoptosis in HCCs, whereas the low basal apoptosis rate in the non‐tumorous liver parenchyma did not change. Tumor cell proliferation was mildly reduced, but the changes did not reach statistical significance. These results demonstrate that the precision‐cut tissue slice culture model is a useful tool to analyze directly drug‐dependent antitumorous or unwanted organ‐specific effects. The analysis of COX‐2 inhibition lends further support to the antineoplastic effects previously demonstrated in vitro and in animal models.
Surveillance of hepatocellular carcinoma in patients with hepatitis C virus infection may improve patient survival
Authors: Tanaka Hironori , Nouso Kazuhiro , Kobashi Haruhiko , Kobayashi Yoshiyuki , Nakamura Shin‐ichiro , Miyake Yasuhiro , Ohnishi Hideki , Miyoshi Kenji , Iwado Shouta , Iwasaki Yoshiaki , Sakaguchi Kohsaku , Shiratori Yasushi
Published: April 2006

Abstract: Background: The benefit of surveillance of hepatocellular carcinoma (HCC) for patients with hepatitis C virus (HCV) infection, in terms of long‐term survival, has not yet been established.

Methods: A total of 384 consecutive anti‐HCV‐positive HCC patients admitted to our hospital between January 1991 and October 2003 were enrolled. Patients were categorized into two groups, a surveillance group (182 patients) and a non‐surveillance group (202 patients), according to tumor detection in a surveillance program based on periodical examination via ultrasound sonography and alpha fetoprotein determination at 6‐month intervals, and their survival rates were compared.

Results: Although there were no significant differences in age and Child–Pugh classes between the two groups, the surveillance group exhibited a smaller tumor size (19 vs. 35 mm) and a higher incidence of single HCC (67% vs. 46%), compared with the non‐surveillance group (each, P<0.001). The cumulative survival rate in the surveillance group was higher than that in the non‐surveillance group (5 years survival, 46% vs. 32%, P<0.001). When the survival after correction of the lead‐time bias in the surveillance group was analyzed according to the Child–Pugh classification, the surveillance program was found to have had a favorable outcome in Child–Pugh class A patients, but not in Child–Pugh class B/C patients.

Conclusions: HCC surveillance for patients with HCV infection can lead to discovery of tumors at an early stage, especially in Child–Pugh class A, resulting in a favorable outcome.
Cytokine blockade inhibits hepatic tissue inhibitor of metalloproteinase‐1 expression and up‐regulates matrix metalloproteinase‐9 in toxic liver injury
Authors: Roderfeld Martin , Geier Andreas , Dietrich Christoph G. , Siewert Elmar , Jansen Bettina , Gartung Carsten , Roeb Elke
Published: April 2006

Abstract: Background: Tissue inhibitor of metalloproteinases (TIMP)‐1, the most important endogenous inhibitor of matrix metalloproteinases, plays a pivotal role in the pathogenesis of liver fibrosis and may represent an effective therapeutic target in the design of antifibrotic strategies for chronic liver diseases.

Methods: Intraperitoneal application of a single dose of either tumor necrosis factor (TNF)‐α or interleukin (IL)‐1β in mice led to an enhanced expression of hepatic TIMP‐1 after 4–16 h. Male Sprague–Dawley rats were treated with carbon tetrachloride (CCl4) in the presence and absence of specific TNF‐α and IL‐1β inhibitors.

Results: Real‐time PCR revealed a significant increase of TIMP‐1 mRNA in total rat liver 24 h after CCl4 injection. Repetitive injection of both, etanercept and anakinra, before and after CCl4 injection effectively inactivated TNF‐α and IL‐1β. Anticytokine pretreatment reduced the increase of TIMP‐1 expression after a single CCl4 injection by 50% and 75%, respectively. In contrast to CCl4‐treated rats with and without TNF‐α blockade, IL‐1β inactivation caused a sevenfold increase in matrix metalloproteinases‐9 mRNA levels.

Conclusions: In conclusion, TIMP‐1 expression is up‐regulated in the early phase of toxic liver injury by proinflammatory cytokines such as TNF‐α and IL‐1β in rodents. Pharmacological inactivation of these cytokines significantly reduces TIMP‐1 gene expression. Our data provide a potential new antifibrotic approach.
Effect of Core Diameter and Surface Treatment on the Retention of Resin Composite Cores to Prefabricated Endodontic Posts
Authors: Artopoulou Ioli‐Ioanna , O'Keefe Kathy L. , Powers John M.
Published: April 2006

Purpose:
With advances in adhesive dentistry and current emphasis on esthetic restorations, dowel systems have been developed to take advantage of these new techniques. Of interest when using these systems is the interaction between core materials and post materials. This investigation compared the tensile retentive force of two resin composite core materials to two metallic and one nonmetallic prefabricated endodontic posts. Two dimensions of core build‐up and two post‐surface treatments were tested.

Materials and Methods:
One hundred twenty posts (stainless steel, titanium alloy, and glass fiber‐impregnated resin) were secured in a jig with 4 mm of the post extending into a cylindrical matrix. The matrix formed cylinders with diameters of 3 and 5 mm into which resin composite was inserted. The posts were treated or not treated with a bonding agent. After storage for 24 hours at 100% humidity, five specimens per condition were tested in an Instron testing machine at a crosshead speed of 0.5 mm/min. Failure loads were recorded in kilograms and failure modes were observed under light microscopy (40×). Four‐way analysis of variance and multiple comparison testing were used to compare means at the 0.05 level of significance.

Results:
The means and standard deviations of tensile loads were calculated. All variables were significant in either main effects or interactions ( p < 0.05). Fisher's PLSD intervals for post, core, treatment, and diameter were 2.0, 1.6, 1.6, and 1.6 kg, respectively. In most cases, the retentive force recorded for metallic posts was higher than that of glass fiber posts. Titanium posts had higher retentive forces than did the stainless steel posts. For metallic posts, 5‐mm cores provided higher forces than 3‐mm cores. In the glass fiber group, core diameter was not significant. For core materials, Build‐It gave higher results with stainless steel posts, and FluoroCore gave higher results with the titanium ones. The surface treatment results were mixed. In the metallic post groups the adhesive failure data ranged between 80% and 100%, whereas in the glass fiber post groups, adhesive failures ranged between 60% and 70%.

Conclusions:
Within the limitations of this study, the metallic post groups always provided higher tensile retentive forces, with the titanium post groups showing higher retentive forces than the stainless steel ones. In the glass fiber post groups, different core diameters did not affect retention values.
Surface Roughness of Denture Base Acrylic Resins After Processing and After Polishing
Authors: Berger Julie C. , Driscoll Carl F. , Romberg Elaine , Luo Qing , Thompson Geoffrey
Published: April 2006

Purpose:
Circumstances exist in which the need to adjust denture base acrylic resins is necessary. This process obviously alters the surface of the polished denture base. The purpose of this study was to compare the effects of three chairside polishing kits and conventional polishing on four denture acrylic resins.

Materials and Methods:
Twenty‐four 30 × 30 × 2 mm acrylic resin specimens were fabricated with each of four acrylic resins: autopolymerizing, heat processed, injection molded, and microwaveable. One side was polished conventionally with pumice and polishing compound. The other side was polished with one of three chairside polishing kits: Axis, Brasseler, and Shofu. Each side was evaluated by a Dektak 8 Programmable Stylus Profiler to determine the surface roughness (Ra).

Results:
One‐way analysis of variance (ANOVA) revealed that: (1) There was no significant difference in the time it took to polish the specimens with the chairside polishing kits (F= 2.118, p= 0.14). (2) There was a significant difference in surface roughness between the acrylic resins before any polishing, with the injection‐molded and heat‐processed being less rough than the autopolymerizing (F= 4.588, p= 0.005). (3) There was a significant difference in surface roughness between the acrylic resins when conventionally polished, with the injection‐molded and microwavable being less rough than the autopolymerizing (F= 4.503, p= 0.005). Factorial ANOVA revealed that: (1) There was no significant difference in the surface roughness among the chairside polishing kits (F= 1.209, p= 0.30). (2) There was a significant difference between the acrylic resins, with the heat‐processed, injection‐molded, and microwaveable being significantly less rough than the autopolymerizing (F= 6.610, p= 0.0001). (3) There was no significant interaction between the acrylic resins and the chairside polishing kit in the amount of surface roughness (F= 1.728, p= 0.12). An independent t‐test revealed that conventional polishing was significantly smoother than polishing with the chairside polishing kits (t= 3.847, p= 0.0001).

Conclusions:
It was concluded that time was not a factor in using any of the chairside polishing kits. It is recommended that conventional polishing be used after adjustments to the cameo surface of denture acrylic resin.
Immediate Occlusal Loading of Osseotite® Implants in Mandibular Edentulous Patients: A Prospective Observational Report with 18‐Month Data
Authors: Drago Carl J. , Lazzara Richard J.
Published: April 2006

Purpose:
To evaluate the efficacy of treatment consisting of placement and immediate occlusal loading of implants in 27 patients with edentulous mandibles.

Materials and Methods:
Twenty‐seven patients were treated in two private practice settings. One hundred fifty‐one implants were placed and immediately occlusally loaded with fixed implant prostheses (15 cement‐retained, 12 screw‐retained) on the day of implant placement. The implant‐retained prostheses were inserted within 5 hours of implant placement. Patients were followed for at least 18 months. The required criteria for immediate occlusal loading was primary implant stability of at least 30 Ncm of insertion torque. The implant prostheses were removed at least 12 months post‐placement and the implants were evaluated for primary clinical stability and radiographic bone apposition to implants.

Results:
At the 12‐month follow‐up appointments, cumulative survival rates of 98.0% and 100% were recorded for implants and prostheses, respectively. Three implants failed within 3 months. All other implants were clinically successful.

Conclusions:
Immediate occlusal loading of multiple, splinted mandibular implants is an effective treatment when implants are stable at insertion and are rigidly splinted with implant‐retained prostheses.
Facial Moulage Fabrication Using a Two‐Stage Poly (vinyl siloxane) Impression
Authors: Alsiyabi Abdullah S. , Minsley Glenn E.
Published: April 2006

Traditional techniques for the fabrication of a facial moulage have relied on materials with various shortcomings. This article describes a two‐stage Poly(vinyl siloxane) impression technique that avoids some of these shortcomings and provides a predictable and accurate facial moulage.
Dentist Communication with the Dental Laboratory for Prosthodontic Treatment Using Implants
Authors: Afsharzand Zahra , Rashedi Behnoush , Petropoulos Vicki C.
Published: April 2006

Purpose: A questionnaire was sent to U.S. dental laboratories to evaluate the level of communication between dentists and laboratory technicians and to determine trends in procedures and materials used in fixed and removable implant restorations.

Methods and Materials: Dental laboratories were randomly chosen from the National Association of Dental Laboratories for each of the 50 states. The questionnaire was mailed to the laboratory directors for 199 dental laboratories. One hundred fourteen dental laboratories returned the survey, yielding a response rate of 57%. Of those laboratories, 37 indicated that they did not participate in the fabrication of fixed implant restorations, yielding a response rate of 39%. Forty‐two dental laboratories indicated that they did not participate in the fabrication of implant‐retained overdenture prostheses, yielding a response rate of 36%.

Results: Results from this survey show inadequate communication by dentists in completing work authorization forms. Custom trays are used more frequently for implant‐retained overdenture impressions and stock trays for impressions of fixed implant prostheses. Poly(vinyl siloxane) is the material most commonly used for both fixed and removable implant‐supported prostheses. Two implants with stud attachments are used more widely than those with bar attachments for implant‐retained overdentures.

Conclusions: Most laboratories working on implant prosthodontic cases report inadequate communication between the laboratory and dentists related to materials and techniques used in fabrication of implant restorations.
Influence of Non‐Stoichiometry on the Structure and Properties of Ba(Zn1/3Nb2/3)O3 Microwave Dielectrics: II. Compositional Variations in Pure BZN
Authors: Wu Hui , Davies Peter K.
Published: April 2006

The formation of non‐stoichiometric cubic perovskite solid solutions based on BaZn1/3Nb2/3O3 (BZN) was examined along 10 different directions in the BaO–ZnO–Nb2O5 ternary system. Limited ranges of non‐stoichiometry were observed along several pseudo‐binaries and the BZN structure can accommodate a variety of different types of defects. Although the deviations from stoichiometry are quite small, typically ∼1 mole%, they induce large changes in the extent and stability of the 1:2 B‐site ordering, the sintering and microstructure, and the dielectric loss properties. The highest Q×fs (∼110 000 at 8 GHz) in the system, which coincide with the highest degree of order, were located in two regions along the BZN–Ba5Nb4O15 and BZN–BaNb2O6 lines. The results of this study provide an explanation for the large variations in crystal structure and Q×fs previously reported for BZN and other related systems (e.g., Ba(Zn1/3Ta2/3)O3), and demonstrate that non‐stoichiometric starting compositions provide a route to the highest Q values.
Influence of Non‐Stoichiometry on the Structure and Properties of Ba(Zn1/3Nb2/3)O3 Microwave Dielectrics. IV. Tuning τf and the Part Size Dependence of Q×f
Authors: Wu Hui , Davies Peter K.
Published: April 2006

High Q ceramics of Ba3W2O9 (BW)‐substituted Ba(Zn1/3Nb2/3) O3 (BZN) were prepared with a zero τf through the partial substitution of Zn by Ni and Co. The small concentrations of B‐site vacancies introduced by the substitution of BW accelerated the kinetics and stability of the cation ordering and lowered the sintering temperature. Dense, zero τf, ordered solid solutions such as 0.99Ba(Zn0.3Co0.7)1/3Nb2/3O3–0.01BW with ɛr=34.4 and Q×f=82 000 at ∼8 GHz could be obtained after sintering at 1380°C for 5 h and annealing at 1300°C for 24 h. Partially ordered ceramics in the Zn/Co and Zn/Ni solid solutions show a large gradient in the ordering throughout the pellets, which produces a resonant frequency dependence of their Q×f value. The ordering gradient is associated with the increased constraints on the growth of the 1:2 ordered structure within the interior of larger and thicker pellets and can be minimized by extended annealing.
Thermal Cycling Damage Mechanisms of C/SiC Composites in Displacement Constraint and Oxidizing Atmosphere
Authors: Mei Hui , Cheng Laifei , Zhang Litong
Published: April 2006

A constraint stress of 62.5 MPa is created on a three‐dimensional C/SiC composite specimen whose both ends are fixed when temperature is cycled between 900° and 1200°C. The cyclic stress results in a maximum damage strain of 0.06% within 50 cycles owing to coating and matrix cracking, fiber debonding, sliding, and breaking in the composite. This constrained specimen elongation also leads to a final compressive stress of 14 MPa on the composite through a decrease in the baseline constraint stress. Wet oxygen atmosphere at a high cyclic temperature, concomitant with stresses, can aggravate the damage situation by alternate oxidation between internal and external fibers in composites.
Synthesis of Nanocrystalline Lanthanum Strontium Manganite Powder by the Urea–Formaldehyde Polymer Gel Combustion Route
Authors: Prabhakaran Kuttan , Joseph Jorly , Gokhale Nitin Madhusudan , Sharma Suresh Chandra , Lal Ramji
Published: April 2006

Nanocrystalline lanthanum strontium manganite (LSM) powder has been synthesized by combustion of a transparent gel obtained by the polymerization of methylol urea and urea in a solution containing La3+, Sr2+, and Mn2+ (LSM ions). Chemistry of the transparent urea–formaldehyde (UF) polymer gel formation and structure of the gel have been proposed such that the LSM ions act in between the growing UF polymer chains by interacting through NH, OH, and CO groups by co‐ordination and prevent polymer self‐assembly through inter‐chain hydrogen bonding as evidenced from infrared spectrum. Thermally stable structures formed by the decomposition of UF polymer below 300°C undergo combustion in the presence of nitrate oxidant in a temperature range from 350°–450°C. A perovskite LSM phase has been formed by self‐sustained combustion of the dried gel initiated with little kerosene. The powder obtained after deagglomeration and calcination at 600°C for 2 h has a D50 value of 0.19 μm, and the particles are aggregates of crystallites 10–25 nm in size.
Phase Behavior, 3‐D Structure, and Rheology of Colloidal Microsphere–Nanoparticle Suspensions
Authors: Rhodes Summer K. , Lewis Jennifer A.
Published: April 2006

A new route for tailoring the behavior of colloidal suspensions through nanoparticle additions is reviewed. Specifically, the interparticle interactions, phase behavior, 3‐D structure, and rheological properties of microsphere–nanoparticle mixtures that possess both high charge and size asymmetry are described. Negligibly charged microspheres, which flocculate when suspended alone, undergo a remarkable stabilizing transition upon the addition of highly charged nanoparticles. The formation of a dynamic nanoparticle halo around each colloid induces an effective repulsion between the microspheres that promotes their stability. With increasing nanoparticle concentration, the colloids again undergo flocculation because of the emergence of an effective microsphere attraction, whose magnitude exhibits a quadratic dependence on nanoparticle volume fraction. The broader impact of these observations on colloidal stabilization and assembly of advanced ceramics is highlighted.
TEM Characterization of Nanostructured MgAl2O4 Synthesized by a Direct Conversion Process from γ‐Al2O3
Authors: Al‐Sharab Jafar F. , Cosandey Frederic , Singhal Amit , Skandan Ganesh , Bentley James
Published: April 2006

Nanostructured MgAl2O4 spinel was synthesized by a direct conversion process from cubic γ‐Al2O3. The effect of post‐annealing temperature (300°, 500°, and 800°C) on MgAl2O4 phase formation was investigated using transmission electron microscopy, selected area electron diffraction (SAED), electron energy loss spectroscopy (EELS), and energy‐dispersive spectroscopy (EDS). Relative diffraction intensities as well as lattice parameter measurements from SAED revealed that MgAl2O4 spinel structure starts forming at temperatures as low as 300°C. EELS and EDS spectrum images also revealed an increase in elemental homogeneity with increasing annealing temperature. The degree of ordering of Mg and Al between octahedral and tetrahedral sites has been determined from relative diffraction intensities. Results show that annealing to 800°C leads to a spinel phase with an order parameter of 0.78.
Machinable α‐SiAlON/BN Composites
Authors: Shuba Roman , Chen I‐Wei
Published: April 2006

Dense machinable α‐SiAlON/BN composites were fabricated by hot‐pressing using turbostratic boron nitride (tBN) obtained from nitridation of melamine diborate. The tBN was added to the starting powders, or introduced as a coating that formed in situ on α‐Si3N4 carrier powders during nitridation, and was subsequently converted to hexagonal boron nitride (hBN) during hot pressing by solution reprecipitation. These composites maintain high strength at 1000°C and their strength/hardness are much higher than similar composites prepared using commercial hBN powder, which yielded a coarser microstructure. Good machinability was achieved despite a flat R curve.
Microwave Dielectric Ceramics for Resonators and Filters in Mobile Phone Networks
Authors: Reaney Ian M. , Iddles David
Published: April 2006

Temperature‐stable, medium‐permittivity dielectric ceramics have been used as resonators in filters for microwave (MW) communications for several decades. The growth of the mobile phone market in the 1990s led to extensive research and development in this area. The main driving forces were the greater utilization of available bandwidth, that necessitates extremely low dielectric loss (high‐quality factor), an increase in permittivity so that smaller components could be fabricated, and, as ever in the commercial world, cost reduction. Over the last decade, a clear picture has emerged of the principal factors, that influence MW properties. This article reviews these basic principles and gives examples of where they have been used to control microwave properties and ultimately develop new materials.
Fabrication and Properties of Sol–Gel‐Derived BiScO3–PbTiO3 Thin Films
Authors: Wen Hai , Wang Xiaohui , Li Longtu
Published: April 2006

BiScO3–PbTiO3 (BSPT) thin films near the morphotropic phase boundary were successfully fabricated on Pt(111)/Ti/SiO2/Si substrates via an aqueous sol–gel method. The thin films exhibited good crystalline quality and dense, uniform microstructures with an average grain size of 50 nm. The dielectric, ferroelectric, and piezoelectric properties of the sol–gel‐derived BSPT thin films were investigated. A remanent polarization of 74 μC/cm2 and a coercive field of 177 kV/cm were obtained. The local effective piezoelectric coefficient d*33
was 23 pC/N at 2 V, measured by a scanning probe microscopy system. The dielectric peak appeared at 435°C, which was 80°C higher than that of Pb(Ti, Zr)O3 thin films.
Fabrication of HAp‐Coated Micro‐Channelled t‐ZrO2 Bodies by the Multi‐Pass Extrusion Process
Authors: Kumar Gain Asit , Lee Byong‐Taek
Published: April 2006

HAp‐coated micro‐channelled t‐ZrO2 bodies were fabricated using a multi‐pass extrusion process in which carbon powders were used to facilitate the formation of pores and ethylene vinyl acetate was used as a binder. The unidirectional pores and HAp coating layers can be obtained easily, using the extrusion process. The micro‐channelled bodies were 180 μm in diameter, and the HAp layer was uniformly coated on the pore walls. However, after being sintered above 1200°C, the HAp decomposed and was transformed into β‐TCP, in which a large number of pores were observed. The maximum values of bending strength of HAp‐coated and uncoated porous t‐ZrO2 bodies sintered at 1500°C were about 116 and 173 MPa, respectively, and their relative densities were about 57% and 63%, respectively.
Phase Evolution and Microwave Dielectric Properties of Lanthanum Borate‐Based Low‐Temperature Co‐Fired Ceramics Materials
Authors: Seo Yong Jun , Shin Dong Joo , Cho Yong Soo
Published: April 2006

A new potential low‐temperature co‐fired ceramics (LTCC) system based on a simple lanthanum borate (La2O3–B2O3) glass was investigated with regard to phase development and microwave dielectric properties as functions of alumina filler content less than 50 wt% and firing temperature up to 1050°C. Unexpected crystalline phases, such as La(BO2)3, LaAl2.03(B4O10)O0.54, LaBO3, and Al20B4O36, developed during the firing process are likely responsible for substantial resultant changes in physical and microwave dielectric properties. As a specific example, a high‐quality factor of 785 at 15.8 GHz obtained for a composition containing 30 wt% alumina supports the hypothesis that the phase‐dielectric property relation exists in this LTCC system. On a practical basis, two phases of LaAl2.03(B4O10)O0.54 and LaBO3 must be important in determining the final dielectric performance by manipulating the ratios of glass and filler and by selecting a desirable temperature.
Preparation and Properties of Porous α‐Al2O3 Membrane Supports
Authors: Shqau Krenar , Mottern Matthew L. , Yu Di , Verweij Henk
Published: April 2006

Strong and permeable macro‐porous α‐Al2O3 membrane supports are made by colloidal filtration of 20 vol% dispersions of α‐Al2O3 with an average particle size of 600 nm. Intact compacts with very good surface quality were obtained at an optimum pH of 9.5 and dosage of 0.2 wt% ammonium aurintricarboxylate (Aluminon), based on dry alumina. The colloidal stability of the aluminon‐stabilized slurries is confirmed by ξ potential measurements. Slight sintering of dense‐packed α‐Al2O3 compacts was found to result in >67% packing density and a bimodal pore‐size distribution as derived from shrinkage behavior and gas adsorption studies. Non‐stationary single gas permeation measurements showed improved gas permeability, compared with α‐Al2O3 compacts prepared using powder with a smaller particle size (300 nm). The strength of the disk‐shaped alumina compacts within the porosity range of 30%–20% increased from 100 to 300 MPa with a standard deviation of 20 and 50 MPa, respectively.
Electrospinning Zirconia Fiber From a Suspension
Authors: Zhang H. B. , Edirisinghe M. J.
Published: April 2006

A zirconia suspension containing 5–10 nm size zirconia particles was modified by adding different amounts of polymer solution to enable electrospinning of zirconia fibers from a range of compositions. The electrospun fibers were heat treated at 600° and 1200°C, and analysis of size distribution reveals that zirconia fibers down to about 200 nm in diameter can be prepared in this way, in contrast to other spinning processes, which are able to produce zirconia fibers having diameters ≥3000 nm.
Synthesis and Performance of Advanced Ceramic Lasers
Authors: Ikesue A. , Aung Yan Lin
Published: April 2006

This paper reports recent progress in the production of polycrystalline Nd:YAG (Y3Al5O12), Nd:YSAG (Y3Sc1.0Al4.0O12), Yb:YSAG ceramics, and a Nd‐doped YAG single crystal with an almost perfect pore‐free structure by advanced ceramic processing. The laser conversion efficiency of pore‐free polycrystalline Nd‐ and Yb‐doped ceramics is extremely high, and their optical qualities are comparable with that of commercial high‐quality Nd:YAG single crystals. We have also succeeded in the fabrication of a Nd:YAG single crystal, which can be used for laser oscillation, by the solid‐state reaction method. Laser oscillation efficiency was very low when the pores remained inside the single crystal; however, the laser oscillation efficiency of the pore‐free Nd:YAG single crystal was slightly higher than that of polycrystalline Nd:YAG ceramics having high optical quality. From this fact, it was recognized that optical scattering occurs mainly in the residual pores inside the Nd:YAG ceramics and the scattering at the grain boundary is very less. In addition, we confirmed that a heavily doped Nd:YAG single crystal can be fabricated by the sintering method. Moreover, we have demonstrated the fabrication of a composite ceramic with complicated structures without the need for precise polishing and diffusion bonding. Advanced ceramic processing, which enables design flexibility of the laser element, presented in this work is important in the development of a high‐performance laser (high efficiency, high beam quality, and high output energy, etc.)
Dermal vascular IgA deposits in IgA nephropathy secondary to alcohol abuse
Authors: Smith Suzanne Meleg , Hoy Wendy E.
Published: April 2006

Skin, kidney and liver samples were investigated from 103 people with evidence of alcohol abuse at forensic autopsy. The diagnosis of alcohol abuse was based on clinical history, post mortem blood alcohol level and liver pathology. The findings confirmed the frequent widespread vascular IgA deposition in individuals with evidence of alcohol abuse. The frequency of IgA deposition in superficial small vessels of the dermis was not significantly different between individuals with IgA nephritis (16/85) and without such pathology (7/38). Based on these results, it can be inferred that had a pre‐mortem skin biopsy been performed, it would not have had clinical usefulness in predicting the renal disease.
Immunocompetent cells and epithelial cell modifications in molluscum contagiosum
Authors: Viac J. , Chardonnet Y.
Published: April 2006

We studied lesions of molluscum contagiosum with a panel of monoclonal antibodies to determine the phenotype of infiltrating cells and antigen modifications of infected keratinocytes. Our data indicate (1) a complete lack of immunocompetent cells in the viral lesions, and simultaneously a loss of B2‐microglobulin reactivity by molluscum bodies, a cellular activation of EGF and transferrin receptors and expression of CD36 antigen of these bodies; (2) a moderate infiltrate of activated T cells and monocytes in the underlying epidermis; (3) an increase of Langerhans cell density and a CD36 expression by the surface of upper layer keratinocytes in the perilesional epidermis.
Histological diagnostic criteria for accessory tragi
Authors: Satoh T. , Tokura Y. , Katsumata M. , Sonoda T. , Takigawa M.
Published: April 2006

The histological features of accessory tragi from 13 patients were analyzed. All the lesions showed numerous tiny mature hair follicles in various phases, while the presence of cartilage was not essential. Of importance was the prominent connective tissue framework in the subcutaneous fat that seemed to be one of the diagnostic criteria for accessory tragi.
Eccrine spiradenoma occurring in infancy mimicking mesenchymal tumor
Authors: Kao Grace F. , Laskin William B. , Weiss Sharon W.
Published: April 2006

Eccrine spiradenoma (ES) rarely (less than 1%) occurs in infancy. These tumors differ from the conventional ES by the presence of superficial dermal nodules which display a less distinct two‐cell pattern of immature adnexal epithelial cells and rarely ductule formation. These tumors may be mistaken for mesenchymal neoplasms involving the skin and subcutis of infants and young adults. Recognition of the histopathologic features and immunostains are required to make a definte diagnosis. We describe 2 cases of ES occurring in patients younger than one year. Detailed histopathologic and histochemical differential features of these tumors and mesenchymal neoplasms of the skin and subcutis commonly occurring in infants and young adults are discussed. The biologic behavior of infantile ES is benign, but complete excision is recommended to prevent recurrence. We speculate that these tumors may represent congenital hamartomatous growths.
Actinic granuloma‐like change in exogenous ochronosis: case report
Authors: Jordaan H. F. , Mulligan R. P.
Published: April 2006

Exogenous ochronosis is caused by the longterm application of skin‐lightening creams containing hydroquinone. This irreversible disfiguring cosmetic problem assumes epidemic proportions in South African blacks. Mild ochronosis is characterized clinically by coarsening and darkening of the skin and severe ochronosis by coalescing, caviar‐like black papules and atrophy. Histology shows occhronotic collagen fibres with eventual formation of ochronotic colloid milium. A variable cellular infiltrate, which may be granulomatous, is present. We describe a 39‐year‐old black woman with severe exogenous ochronosis who developed superimposed annular lesions with granulomatous histology bearing great resemblance to lesions of actinic granuloma.
Plaque‐type blue nevus combined with lentigo (nevus spilus)
Authors: Ishibashi A. , Kimura K. , Kukita A.
Published: April 2006

Three cases of plaque‐type blue nevus accompanied with lentigo‐like changes were reported. The combination of blue nevus and lentigo (nevus spilus) is a new type of “combined nevus”, but it belongs to the second type of Kawamura's atypical blue nevus. This combination is unlikely to be rare, not only in plaque‐type, but also in common type blue nevus, and to be comparable with the findings of such dermal melanocytosis as nevus of Ota. Histologically, cellular blue nevus was also observed in areas of Case 1.
A case of subungual amelanotic malignant melanoma: an electron microscopic study of aberrant melanosomes
Authors: Matsuta M. , Segawa I. , Akasaka T. , Kon S. , Nara T. , Minato S.
Published: April 2006

A 68‐year‐old woman with amelanotic malignant melanoma (AMM) of her left thumbnail bed was reported. The tumor cells were positive with S‐100 protein. Electron microscopic findings revealed the presence of typical melanosomes and a variety of aberrant melanosomes within the tumor cells, obviously different from the results for common malignant melanoma.
Immunohistochemical characterization of palisaded, encapsulated neuroma
Authors: Argenyi Zsolt B.
Published: April 2006

Eleven cases of palisaded, encapsulated neuroma (PEN) were studied by routine light microscopic and immunohistochemical methods. PEN showed the following staining reactions: strong, diffuse for S‐100 protein (11/11) and collagen Type IV (Col. IV) (11/11); moderately strong, focal for myelin basic protein (MBP) (9/11) and Leu‐7 (9/11); weak, focal for MBP (2/11), Leu‐7 (2/11), neuron specific enolase (NSE) (4/11), neural filaments (NF) (5/11), epithelial membrane antigen (EMA) (6/ 11), and negative for glial fibrillary acidic protein (GFAP). Bielschowsky silver stain was positive in 11/11, but only four cases contained numerous axons. Col. IV and EMA stains showed a complete capsule in 1/11, incomplete capsules in 5/11 and no discernible capsules in the remainder. We concluded that (1) the immunologic profile of PEN is not specific; (2) conventional silver stain remains a suitable method to demonstrate axon‐like structures; (3) the ratio of axons to Schwann cells is variable and generally less than 1:1, as previously assumed; (4) MBP and Leu‐7 coexpression in Schwann cells suggests myelinization of some of the nerve fibers; (5) the pattern of EMA reaction supports perineurial cell involvement in PEN; and (6) despite the current definition of PEN, they are usually not completely encapsulated as evidenced by Col. IV and EMA stains.
Location of basement membrane Type IV collagen beneath subepidermal bullous diseases
Authors: Pardo R. J. , Penneys N. S.
Published: April 2006

Using standard immunohistochemical methods, routinely processed sections, and a polyclonal antibody to Type IV collagen, we have determined the location of Type IV collagen, a substance located in the lamina densa of basement membranes, in a spectrum of acquired subepidermal bullous diseases. Type IV collagen was attached to the blister roof in five cases of well‐established epidermolysis bullosa acquisita and to the blister base in 25 cases of bullous pemphigoid, four cases of dermatitis herpetiformis and 12 cases of porphyria cutanca tarda. Immunohistochemical localization of Type IV collagen in epidermal‐dermal basement membrane is a simple, rapid and reliable technique which can be utilized to exclude and possibly to confirm the diagnosis of epidermolysis bullosa acquisita in routinely fixed paraffin‐embedded tissues.
Evaluation of DNA ploidy in dysplastic and Spitz nevi by flow cytometry
Authors: Winokur Thomas S. , Palazzo Juan P. , Johnson Wayne C. , Duray Paul H.
Published: April 2006

As many as 40% of all primary cutaneous melanomas can have histologic remnants of nevomelanocytic nevi adjacent to the tumor. There is increasing evidence that dysplastic nevi are at least a clinical marker for melanoma risk. Spitz nevi are not known for such an association, but are noteworthy because of their histologic appearances. Spitz and dysplastic nevi were studied by flow cytometry to search for DNA abnormality. The study material consisted of formalin‐fixed, paraffin embedded material of 41 dysplastic nevi and 14 Spitz nevi. Four cases of dysplastic nevi were excluded for technical reasons. Of the 37 interpretable histograms from dysplastic nevi, 28 (76%) were diploid and nine (24%) were aneuploid. All the Spitz nevi were diploid. Thus, dysplastic nevi, but not Spitz nevi, share aneu‐ploidy features in some cases with melanoma. Previous authors have demonstrated aneuploidy in mlanoma with aggressive behavior and in those in deep vertical growth phase. Aneuploidy may be a feature of early as well as late stages of tumor progression regarding the nevomelanocyte system.
Syringoma‐like sweat duct proliferation in scalp alopecias
Authors: Mehregan Amir H. , Mehregan David A.
Published: April 2006

We have reviewed a series of 585 scalp biopsies taken for histologic evaluation of hair loss and have looked for syringoma‐like eccrine sweat duct proliferation. This feature was found in 6 specimens with scarring alopecia and one each with alopecia areata and female‐pattern alopecia. Syringoma‐like sweat duct proliferation appears to play no role in the etiology of hair loss.
Digital papular calcific elastosis: a histopathological, histochemical and ultrastructural study of 20 patients
Authors: Francois Jordaan H. , Rossouw Daniël J.
Published: April 2006

In 1960, 5 patients were reported with a condition termed “degenerative collagenous plaques of the hands”. Ultraviolet light and chronic pressure seem to be the inciting factors. Clinically, it is characterized by keratotic, translucent papules, in linear array, on the radial border of the hands. Histology shows hyperkeratosis and dermal elastosis. The current study documented the histopathological, histochemical and ultrastructural features of 20 patients with this condition and considered the differential diagnoses. The findings were in accordance with those of previous studies, but peculiar, basophilic elastotic masses (BEMs), were a prominent finding. Ultrastructurally, elastic tissue appeared in the form of degenerated non‐fragmented and fragmented elastic fibres, degenerated fibres showing foci of increased density, with or without a fibrillar component and as amorphous, structureless material. BEMs arose almost exclusively from degenerated elastic tissue and contained calcium. Disintegrated collagen may be incorporated in the amorphous material and, subsequently, form a minor part of BEMs. Solar elastosis, and its variants, show some similarity to degenerative collagenous plaques of the hands, but lack the constant presence of these calcified angular elastotic masses. BEMs show resemblance to elastic globes, and elastotic bodies found in elastotic nodules of the anthelix and cartilage‐hair hypoplasia. In the clinical setting of “degenerative collagenous plaques of the hands”, BEMs seem to be unique and due to their extensive presence serve as a non‐specific marker for this condition. Digital papular calcific elastosis therefore seems to be more appropriate nomenclature.
Trichoblastic fibroma
Authors: Requena L. , Renedo G. , Sarasa J. , Hasson A. , de Castro A.
Published: April 2006

We report a trichoblastic fibroma in the groin of a 60‐year‐old woman. This unusual tumor showed a predominance of epithelial component, with abundant basophilic, well‐circumscribed, epithelial lobules and some keratinous cysts. Several areas suggested stromal induction of differentiation, and in the keratinous cysts there were indications of outer hair sheath differentiation. We review the clinical data from published cases of trichogenic hair germ tumors and discuss the differential diagnosis.
Squamous cell carcinoma in situ overlying dermatofibroma
Authors: Herman Kenneth L. , Kantor Gary R. , Katz Sheila M.
Published: April 2006

There are occasional reports of benign proliferative epidermal changes overlying dermatofibromas and rare cases of invasive basal cell carcinoma. We report the first case to our knowledge of a dermatofibroma with overlying in situ squamous cell carcinoma.