bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Roughness in Ceramics with Different Finishing Techniques Using Atomic Force Microscope and Profilometer
Authors: Tholt B. , Miranda-Júnior W. G. , Prioli R. , Thompson J. , Oda M.
Published: January 2008

Clinical Relevance

Ceramic restorations often require intraoral adjustment and the use of a polishing kit is mandatory to re-establish surface smoothness. When the ceramic surface was ground and polished, the 3 types of ceramic restorations reacted differently to each tested polishing kit. Some of the polished surfaces obtained were at least equivalent to glaze-fired ceramic surfaces.
Morphological and Mechanical Characterization of the Acid-base Resistant Zone at the Adhesive-dentin Interface of Intact and Caries-affected Dentin
Authors: Inoue G. , Tsuchiya S. , Nikaido T. , Foxton R. M. , Tagami J.
Published: January 2008

Clinical Relevance

A self-etching primer adhesive system, Clearfil SE Bond, may be able to prevent secondary caries around composite restorations in which an acid-base resistant zone was observed beneath the hybrid layer after acid-base challenge.
Direct Pulp Capping with a Dentin Bonding System in Human Teeth: A Clinical and Histological Evaluation
Authors: Silva G. A. B. , Lanza L. D. , Lopes-Júnior N. , Moreira A. , Alves J. B.
Published: January 2008

This study evaluated the pulpal response in human dental pulp to direct pulp capping with the Single Bond Adhesive System (SBAS) after 10% or 37% phosphoric acid etching and after capping with Calcium Hydroxide (CH). The degree of bleeding and hemostasis conditions was considered during the adhesive technique. The pulps of 78 sound premolars were capped with SBAS after 37% phosphoric acid etching (Group I) or 10% phosphoric acid etching (Group II) and CH (Group III-control). The cavities were restored with a resin composite (Charisma). After 1, 3, 7 and 30 days, the teeth were extracted and processed for light microscopical examination (H/E, AgNOR silver stain and Brown-Brenn). The patients were followed for postoperative symptomatology evaluation. Clinical results showed the possibility of hemostasis with saline solution only. There was no statistical difference between bleeding generated by 10% and 37% acid solutions. In some cases, contact of the pulp tissue with SASB started the bleeding process, thus damaging the adhesive technique. The histological response was similar in Groups I and II, without signs of cellular differentiation and dentin neoformation up to 30 days. Bacteria were not observed in any specimens. In the control group (CH) at day 7, the pulps exhibited cells with high synthetic activity (Ag-NOR-positive) underneath the area of coagulation necrosis. Dentin bridging was observed at the thirtieth day. The postoperative period was asymptomatic for all groups. In conclusion, SBAS should be avoided for vital pulp therapy, while CH remains the capping agent of choice for mechanically exposed human dental pulp.
Light Protection of Fiber-reinforced Strip Using Aluminum Foil for the Direct Splinting Technique
Authors: Anagnostou M. , Papazoglou E. , Mountouris G. , Gaintantzopoulou M.
Published: January 2008

Clinical Relevance

Double-folded aluminum foil can be used to protect the fiber-reinforced strip from premature polymerization in a wrong position.
The Effect of Different Bleaching Agents on the Surface Texture of Restorative Materials
Authors: Polydorou O. , Hellwig E. , Auschill T. M.
Published: January 2008

Clinical Relevance

In-office and home bleaching agents do not cause changes that would demand replacement of the restorations when the agents are applied on the polished surfaces of aesthetic dental restorative materials. Repolishing of the composites is suggested in order to overcome possible problems that might result from slight surface changes produced by bleaching.
Effect of Cavity Disinfection on Postoperative Sensitivity Associated with Amalgam Restorations
Authors: Al-Omari W. M. , Al-Omari Q. D. , Omar R.
Published: January 2008

Clinical Relevance

Using a cavity disinfectant such as chlorhexidine before placing an amalgam restoration decreases postoperative sensitivity to cold stimulus.
Effect of Time and Polymerization Cycle on the Degree of Conversion of a Resin Composite
Authors: Schneider L. F. J. , Consani S. , Ogliari F. , Correr A. B. , Sobrinho L. C. , Sinhoreti M. A. C.
Published: January 2008

Clinical Relevance

Initial and final resin composite properties will depend on the photo-activation condition applied.
The Effect of Hydrogel and Solution of Sodium Ascorbate on Bond Strength in Bleached Enamel
Authors: Kimyai S. , Valizadeh H.
Published: January 2008

Clinical Relevance

Both forms of sodium ascorbate (hydrogel and solution) can significantly increase the bond strength of resin composite to enamel after bleaching.
5-year Clinical Performance of Resin Composite Versus Resin Modified Glass Ionomer Restorative System in Non-carious Cervical Lesions
Authors: Franco E. B. , Benetti A. R. , Ishikiriama S. K. , Santiago S. L. , Lauris J. R. P. , Jorge M. F. F. , Navarro M. F. L.
Published: January 2008

Clinical Relevance

A long-term evaluation of the materials' behavior is relevant for Class V restorations in which clinical performance is particularly challenging.
Influence of Bleaching Agents and Desensitizing Varnishes on the Water Content of Dentin
Authors: Betke H. , Kahler E. , Reitz A. , Hartmann G. , Lennon Á , Attin T.
Published: January 2008

Clinical Relevance

The dehydration of tooth structure is discussed as a possible factor for tooth hypersensitivity arising during bleaching; however, it still remains unclear to what extent glycerine-based bleaching gels dehydrate dentin and whether dentin hydration can be maintained by protective dentin varnishes.
Efficiency of 4 Caries Excavation Methods Compared
Authors: Lennon ÁM. , Buchalla W. , Rassner B. , Becker K. , Attin T.
Published: January 2008

Clinical Relevance

Fluorescence Aided Caries Excavation achieves a better combination of excavation time and successful removal of infected dentin compared to conventional excavation, caries detector dye and chemomechanical caries removal.
Shear Bond Strength of the Amalgam-Resin Composite Interface
Authors: Machado C. , Sanchez E. , Alapati S. , Seghi R. , Johnston W.
Published: January 2008

Clinical Relevance

On the basis of the results of this in vitro study, resin composite may be an effective way to repair or mask the appearance of amalgams placed in visible areas of the mouth.
Effect of Intermediate Agents and Pre-heating of Repairing Resin on Composite-repair Bonds
Authors: Papacchini F. , Magni E. , Radovic I. , Mazzitelli C. , Monticelli F. , Goracci C. , Polimeni A. , Ferrari M.
Published: January 2008

Clinical Relevance

The combination of a flowable composite as an intermediate agent and a repairing material at a temperature of 23°C or 37°C prior to light curing may be recommended as a simple, suitable procedure to provide higher bond strengths and uniform composite-to-composite interfacial adaptation.
Influence of Water-storage Time on the Sorption and Solubility Behavior of Current Adhesives and Primer/Adhesive Mixtures
Authors: Reis A. F. , Giannini M. , Pereira P. N. R.
Published: January 2008

Clinical Relevance

The simplified one-step self-etching adhesive and primer/adhesive blends presented high water sorption values that increased with increased water-storage time. High water sorption and solubility values might be related to marginal discoloration and degradation of the bond.
The Influence of Internal Surface Treatments on Tensile Bond Strength for Two Ceramic Systems
Authors: Kiyan V. H. , Saraceni C. H. C. , Silveira B. L. , Aranha A. C. C. , Eduardo C. P.
Published: January 2008

Clinical Relevance

Appropriate surface treatment in ceramic restorations is an important step in the cementation process and should be conducted for each type of ceramic.
Amalgam and Composite Posterior Restorations: Curriculum Versus Practice in Operative Dentistry at a US Dental School
Authors: Ottenga M. E. , Mjör I. A.
Published: January 2008

Clinical Relevance

There is an undeniable move away from amalgam towards the use of resin composite restorations in posterior teeth. The data from one dental school suggests that dental curricula are not keeping pace with the clinical shift that has occurred.
Eight In-office Tooth Whitening Systems Evaluated In Vivo: A Pilot Study
Authors: Matis B. A. , Cochran M. A. , Franco M. , Al-Ammar W. , Eckert G. J. , Stropes M.
Published: January 2008

Clinical Relevance

Rapid bleaching is the main advantage of in-office bleaching; however, there is also a rapid reversal that occurs with most in-office products after bleaching.
Sealing of Minimally Invasive Class II Fillings (slot) Using an Adhesive Patch: Sealant Margin Extension for Prevention
Authors: Schmidlin P. R. , Seemann R. , Filli T. , Attin T. , Imfeld T.
Published: January 2008

Clinical Relevance

The sealing of minimally invasive restorations using a prefabricated adhesive patch significantly reduces leakage and caries formation.
Tensile Bond Strength and Flexural Modulus of Resin Cements—Influence on the Fracture Resistance of Teeth Restored with Ceramic Inlays
Authors: Habekost L. V. , Camacho G. B. , Demarco F. F. , Powers J. M.
Published: January 2008

Clinical Relevance

The mechanical properties of resin cement can influence the fracture resistance of teeth restored with ceramic inlays. In general, cement with a higher elastic modulus resulted in a tooth/ceramic inlay that had a higher fracture resistance.
In Vitro Comparison of Four Different Dental X-ray Films and Direct Digital Radiography for Proximal Caries Detection
Authors: Alkurt M. Torman , Peker I. , Bala O. , Altunkaynak B.
Published: January 2008

Clinical Relevance

F-speed films and digital technologies provide remarkable radiation dose reduction and have equal diagnostic performance with E-speed films for proximal caries detection.
In Vitro Fracture Resistance of Endodontically-treated Maxillary Premolars
Authors: Oskoee S. S. , Oskoee P. A. , Navimipour E. J. , Shahi S.
Published: January 2008

Clinical Relevance

Horizontal pins alone, or with flowable composite, have no effect on the fracture resistance of endodontically-treated maxillary premolars restored with resin composite.
Marginal and Internal Adaptation of Bulk-filled Class I and Cuspal Coverage Direct Resin Composite Restorations
Authors: Stavridakis M. M. , Kakaboura A. I. , Ardu S. , Krejci I.
Published: January 2008

Clinical Relevance

C-factor has an important influence on marginal and internal adaptation in large posterior cavities. A thick bonding layer does not optimize adaptation in Class I restorations.
Role of Additional Retention on Marginal Adaptation and Sealing of Large Resin Composite Class II Restorations
Authors: Ishikiriama S. K. , Mondelli R. F. L. , Kano S. C. , Ishikiriama A. , Mondelli J.
Published: January 2008

Clinical Relevance

Retention grooves in proximal box cavities can minimize microleakage and improve marginal adaptation of large resin composite Class II restorations.
Evaluation of Curing Light Distance on Resin Composite Microhardness and Polymerization
Authors: Rode K. M. , Kawano Y. , Turbino M. L.
Published: January 2008

Clinical Relevance

Different light curing units, the thickness of the resin composite increments and the exposure distance to a curing light may change the physical properties of a restorative material and compromise its mechanical behavior under clinical loading conditions. Understanding how these factors can affect the quality of restorative products may help the dental professional in selecting the best activating source for a specific clinical application.
Effect of Single Step Adhesives on the Marginal Permeability of Class V Resin Composites
Authors: Owens B. M. , Johnson W. W.
Published: January 2008

Clinical Relevance

According to this study, Clearfil S3 bond showed less restoration leakage compared to the other self-etch adhesives at both enamel and dentin margins.
Effect of Different Fluoridation Regimes on the Microhardness of Bleached Enamel
Authors: Wiegand A. , Schreier M. , Attin T.
Published: January 2008

Clinical Relevance

Fluoridation is effective in preventing microhardness loss due to bleaching, but additional fluoride gel supplementation is not superior to toothpaste fluoridation alone.
Microtensile Bond Strength of Resin Composite Bonded to Caries-affected Dentin with Three Adhesives
Authors: Omar H. , El-Badrawy W. , El-Mowafy O. , Atta O. , Saleem B.
Published: January 2008

Clinical Relevance

Compared to two other adhesives, a self-etch adhesive resulted in higher microtensile bond strength values when used to bond a resin composite to both sound and caries-affected dentin.
Comparative Study of Smile Analysis by Subjective and Computerized Methods
Authors: Basting R. T. , Trindade R. S. , Flório F. M.
Published: January 2008

Clinical Relevance

In order to define the esthetic rehabilitation of the smile, smile analysis must be assessed in association with the face, taking into consideration the following factors: midline of the smile, labial line, smile line, the line between commissures and the golden proportion.
A Case for Rubber Dam Application—Subcutaneous Emphysema After Class V Procedure
Authors: Chan D. C. N. , Myers T. , Sharawy M.
Published: January 2008

Clinical Relevance

Subcutaneous emphysema after dental treatment occurs frequently, especially in older patients. Dentists should be aware of the etiology, the differential diagnosis and how to avoid and properly treat such situations.
Effects of Temperature on the Fluoride Release and Recharging Ability of Glass Ionomers
Authors: Yan Z. , Sidhu S. K. , Mahmoud G. A. , Carrick T. E. , McCabe J. F.
Published: January 2008

Clinical Relevance

The use of a higher temperature during topical fluoride applications may increase the fluoride recharging and re-release ability of glass ionomers, and a low oral environment temperature should be avoided during topical fluoride application.
Shear Bond Strength of Dual-cured and Self-cured Resin Composites to Dentin Using Different Bonding Agents and Techniques
Authors: Leevailoj C. , Ua-wutthikrerk P. , Poolthong S.
Published: January 2008

Clinical Relevance

When using resin composites as core buildup materials, dual-cured resin composites show higher shear bond strength to dentin than self-cured resin composites. Light activation of bonding agents prior to applying a resin composite core can improve the shear bond strength of resin composites to dentin.
Restoration Interface Microleakage Using One Total-etch and Three Self-etch Adhesives
Authors: Deliperi S. , Bardwell D. N. , Wegley C.
Published: January 2008

Clinical Relevance

The common belief that simpler, speedier, more user-friendly adhesives always reduce technique sensitivity should be revaluated. Clinicians should resist the attraction of new, faster, easier-use materials and ask for laboratory and clinical studies before switching to a new material.
Surface Roughness of Novel Resin Composites Polished with One-step Systems
Authors: Ergücü Z. , Türkün L. S.
Published: January 2008

Clinical Relevance

One-step systems can polish resin composites containing nanoparticles with a reduced time application; however, their effectiveness depends on material properties.
Influence of Air Abrasion and Long-term Storage on the Bond Strength of Self-etching Adhesives to Dentin
Authors: França F. M. G. , Santos A. J. S. , Lovadino J. R.
Published: January 2008

Clinical Relevance

The adhesiveness of self-etching systems, used with aluminum oxide air abrasion to dentin, decreases over time.
Effect of Pulp Pressure on the Micropermeability and Sealing Ability of Etch & Rinse and Self-etching Adhesives
Authors: Rosales-Leal J. I. , de la Torre-Moreno F. J. , Bravo M.
Published: January 2008

Clinical Relevance

Etch & rinse adhesives are much more micropermeable and affected by pulp fluid compared with self-etching adhesives. Pulp pressure reduces dentin sealing with etch & rinse adhesives but not with self-etching adhesives. Pulp pressure has no effect on enamel sealing, which is lower when self-etching adhesive is used.
A Clinical Study on Interdental Separation Techniques
Authors: Loomans B. A. C. , Opdam N. J. M. , Roeters E. M. , Bronkhorst F. J. M. , Dörfer C. E.
Published: January 2008

Clinical Relevance

When separation is required for restorative procedures, special separation rings may be more useful than wooden wedges.
The Importance of Dentin Collagen Fibrils on the Marginal Sealing of Adhesive Restorations
Authors: Maior J. R. S. , Figueira M. A. S. , Netto A. B. A. B. , Souza F. B. , Silva C. H. V. , Tredwin C. J.
Published: January 2008

Clinical Relevance

The results of this research showed that, with regard to marginal seal, collagen fibrils were not essential to obtaining an optimal adhesive performance. Deproteinization should be considered as a bonding pre-treatment.
Effects of Sonic and Ultrasonic Scaling on the Surface Roughness of Tooth-colored Restorative Materials for Cervical Lesions
Authors: Lai Y. L. , Lin Y. C. , Chang C. S. , Lee S. Y.
Published: January 2008

Clinical Relevance

Both sonic and ultrasonic periodontal instrumentations may roughen the surface of tooth-colored restorative materials for Class V cavities. In general, glass ionomers are more prone to surface alterations than resin-based composites.
The Effect of Marginal Ridge Thickness on the Fracture Resistance of Endodontically-treated, Composite Restored Maxillary Premolars
Authors: Shahrbaf S. , Mirzakouchaki B. , Oskoui S. S. , Kahnamoui M. A.
Published: January 2008

Clinical Relevance

Preserving the marginal ridge of endodontically-treated composite restored maxillary premolars can act as a strengthening factor and improve fracture resistance.
Gingival Microleakage of Class II Resin Composite Restorations with Fiber Inserts
Authors: El-Mowafy O. , El-Badrawy W. , Eltanty A. , Abbasi K. , Habib N.
Published: January 2008

Clinical Relevance

Fiber inserts incorporated at the gingival floor of Class II composite restorations resulted in a significant reduction of microleakage scores as compared to restorations made without inserts. This may lead to a reduced incidence of recurrent caries.
In Vivo Study of Two Carbamide Peroxide Gels with Different Desensitizing Agents
Authors: Matis B. A. , Cochran M. A. , Eckert G. J. , Matis J. I.
Published: January 2008

Clinical Relevance

Under the conditions of this study, 15% carbamide peroxide with potassium nitrate and fluoride exhibited greater bleaching potential but exhibited no difference in sensitivity compared to 16% carbamide peroxide with amorphous calcium phosphate.
Survival of Inlays and Partial Crowns Made of IPS Empress After a 10-year Observation Period and in Relation to Various Treatment Parameters
Authors: Stoll R. , Cappel I. , Jablonski-Momeni A. , Pieper K. , Stachniss V.
Published: January 2008

Clinical Relevance

Ceramic inlays as aesthetic restorations in the posterior region can be used successfully in routine clinical therapy. Cement viscosity, the operator (experienced dentist vs dental student) and the number of surfaces have no influence on longevity.
Cytotoxicity of Composite Materials Polymerized with LED Curing Units
Authors: Knezevic A. , Zeljezic D. , Kopjar N. , Tarle Z.
Published: January 2008

Clinical Relevance

Curing light intensity is one of the main parameters for proper resin composite cure. Inadequate polymerization of a composite can be harmful to vital pulp tissue and can compromise the durability and quality of the final restoration.
Fracture Resistance and Gap Formation of MOD Restorations: Influence of Restorative Technique, Bevel Preparation and Water Storage
Authors: Coelho-de-Souza F. H. , Camacho G. B. , Demarco F. F. , Powers J. M.
Published: January 2008

Clinical Relevance

Beveling of the cavosurface margin can improve resistance to fracture and the marginal adaptation of posterior composite restorations, reducing the deleterious effect of storage with thermal cycling on restoration quality. Generally, indirect restorations showed similar performance compared to direct restorations.
Comparative Clinical Evaluation of Different Treatment Approaches Using a Microfilled Resin Composite and a Compomer in Class III Cavities: Two-year Results
Authors: Demirci M. , Yildiz E. , Uysal Ö
Published: January 2008

Clinical Relevance

For two years, the three restoration/adhesive combinations used in this study (Dyract AP/Prime & Bond NT with NRC pretreatment, Dyract AP/Prime & Bond NT with phosphoric acid pretreatment and Filtek A110/Single Bond) exhibited very good clinical performance in Class III cavities. Clinically simplified systems and handling characteristics of materials may effect their clinical performance.
Durability of Enamel Bonding Using Two-step Self-etch Systems on Ground and Unground Enamel
Authors: Loguercio A. D. , Moura S. K. , Pellizzaro A. , Dal-Bianco K. , Patzlaff R. T. , Grande R. H. M. , Reis A.
Published: January 2008

Clinical Relevance

The effect of surface preparation was adhesive-dependent. Improvements in resin-enamel bond strength after enamel preparation were observed only for AdheSE and Optibond Solo plus Self-Etch Primer. Among the self-etch systems, mild, self-etch Clearfil SE Bond showed the highest bond strength values. No degradation of resin-enamel bonds was observed after 12 months of water storage, regardless of the adhesive tested.
Structure optimisation of short-wavelength ridge-waveguide InGaN/GaN diode lasers
Authors: Karbownik P. , Sarzała R.
Published: January 2008

Room-temperature (RT) continuous-wave (CW) operation of the 405-nm ridge-waveguide (RW) InGaN/GaN quantum-well diode lasers equipped with the n-type GaN substrate and two contacts on both sides of the structure has been investigated with the aid of the comprehensive self-consistent simulation model. As expected, the mounting configuration (p-side up or down) has been found to have a crucial impact on the diode laser performance. For the RT CW threshold operation of the otherwise identical diode laser, the p-side up RW laser exhibits as high as nearly 68°C maximal active-region temperature increase whereas an analogous increase for the p-side down laser was equal to only 24°C. Our simulation reveals that the lowest room-temperature lasing threshold may be expected for relatively narrow and deep ridges. For the structure under consideration, the lowest threshold current density of 5.75 kA/cm2 has been determined for the 2.2-μm ridge width and the 400-nm etching depth. Then, the active-region temperature increase was as low as only 24 K over RT. For wider 5-μm ridge, this increase is twice higher. An impact of etching depth is more essential for narrower ridges. Quite high values (between 120 and 140 K) of the characteristic parameter T0 convince very good thermal properties of the above laser.
Gold-enhanced oxidation of silicon nanowires
Authors: Werner Peter , Büttner Claudia C. , Schubert Luise , Gerth Gerhard , Zakarov Nikolai D. , Gösele Ulrich
Published: January 2008

Silicon nanowires are frequently grown involving a liquid gold droplet at their tips. Here we show that under certain circumstances the thermal oxidation of a silicon nanowire is drastically enhanced by the presence of this gold droplet. Such a gold-enhanced oxidation was observed in a temperature range from 1000 °C down to 250 °C. As a consequence, instead of the slow radial oxidation expected and desired for thinning the nanowires, a fast axial oxidation may occur catalyzed by the gold tip. This leads to a shrinking of the length of the Si nanowire and its replacement by a longer nanowire consisting of silicon dioxide. During this gold-enhanced oxidation process the gold droplet migrates from the tip to the base of the nanowire. Our experiments demonstrate that gold droplets lead to an enhanced dissolution of silicon during oxidation in the case that these remain in intimate contact with the Si nanowires.
Compressive deformation of lamellar microstructures – a short review
Authors: Fischer Franz Dieter , Clemens Helmut , Schaden Thomas , Appel Fritz
Published: January 2008

This paper reviews the essential results of our research on the deformation behavior of fully lamellar microstructures under compressive loading. The most important outcomes, experimentally and theoreticaly, are presented. Usually such fully lamellar microstructures are present in cast intermetallic γ(TiAl)-based alloys; therefore, this class of materials was selected to verify the developed model. During large compressive deformation of γ(TiAl)-based alloys at elevated temperatures the lamellar colonies, depending on their orientation, are often bent or buckled which is representative of a deformation “instability” characterized by a large wave length. Structural defects of the lamellae as well as their somewhat irregular arrangement trigger such a deformation behavior. In addition, kink formation and shear band-type deformation modes occur according to an “instability” mode exhibiting a short wave length. These two deformation modes interact in a rather subtle way, which leads to a very inhomogeneous deformation pattern. A short paragraph on the stability behavior of composites is, therefore, added.
Experimental studies and thermodynamic simulation of phase transformations in high Nb containing γ-TiAl based alloys
Authors: Chladil Harald F. , Clemens Helmut , Zickler Gerald A. , Takeyama Masao , Kozeschnik Ernst , Bartels Arno , Buslaps Thomas , Gerling Rainer , Kremmer Sascha , Yeoh LaReine , Liss Klaus-Dieter
Published: January 2008

Solid-state phase transformations and phase transition temperatures in Ti-45 at.% Al and Ti-45 at.% Al-(5, 7.5, 10) at.% Nb alloys were analyzed experimentally and compared to thermodynamic calculations. Results from scanning electron microscopy, high-energy and conventional X-ray diffraction as well as differential scanning calorimetry were used for the characterization of the prevailing phases and phase transformations. For the prediction of phase stabilities and phase transition temperatures, thermodynamic calculations using the CALPHAD method were conducted. In order to achieve better agreement between calculated and experimental results, a commercially available database was modified using our own results from thermo-physical measurements and annealing treatments.
Enhanced thermal stability of a cobalt–boron carbide nanocomposite by ion-implantation
Authors: daSilva Melina , Klement Uta , Hibbard Glenn D.
Published: January 2008

A first investigation of the thermal stability in a wear resistant cobalt-boron carbide (Co – B4C) nanocomposite has been performed by the combination of calorimetry and transmission electron microscopy. The calorimetric measurements show that the thermal stability of Co – B4C is not influenced by the presence of the 10 vol.% μm-sized boron carbide particles. However, grain growth is shifted to significantly higher temperatures during in-situ annealing (in the transmission electron microscope), and abnormal grain growth is not observed to be as extensive as in conventional nanocrystalline Co. This effect is mainly attributed to the observed implantation of Ga atoms during transmission electron microscope specimen thinning by focused ion beam. Grain boundary segregation mechanisms are discussed as possible reasons for the retarded grain growth.
Development of the unloading stiffness during cyclic plastic deformation of a high-strength aluminium alloy in different tempers
Authors: Hörnqvist Magnus , Karlsson Birger
Published: January 2008

The development of stiffness during unloading from peak stress during cyclic plastic deformation (low cycle fatigue) was studied in a high-strength Al-5.4Zn-1.2Mg alloy, both in naturally aged and peak aged conditions. A phenomenological model based on a order stress – strain relationship was developed using data from detailed recordings of the stress–strain hysteresis loops. Three stages of the parameter values were identified: an initial transition part of the fatigue life time, a major stationary stage shifting over to the final stage where failure modes become prominent. The nonlinear stiffness was found to be asymmetric with respect to tension and compression. Further, the naturally aged material generally shows larger stiffness for both positive and negative stresses than does the peak aged material. Finally, the stiffness for the naturally aged condition exhibits larger scatter compared to the peak aged materials, interpreted as inferior averaging in the dislocation structures.
Numerical determination of parameterised failure curves for ductile structural materials
Authors: Weber Ulrich , Mohanta Ashok , Schmauder Siegfried
Published: January 2008

Inhomogeneities such as voids or inclusions can lead to stress and strain concentrations under external loading conditions due to the different elastic – plastic and thermal properties of the phases. To describe the damage behavior of ductile materials, a damage parameter was introduced by Rice and Tracey and so-called failure curves (determined by experiments) describe different possible stress – strain states at fracture. The experimental effort can be reduced by applying unit cell models consisting of a single void in the base material with a pre-defined void volume fraction f0. With these models, stress triaxialities and plastic strains are calculated and failure curves are derived. Parameter studies are performed to obtain analytical equations for the material dependent constants A and B as a function of the initial void volume fraction f0 and the hardening exponent N as well as the yield stress 0.
Sandwich panels for blast protection in water: simulations
Authors: Spuskanyuk Alexander V. , McMeeking Robert M.
Published: January 2008

Edge supported metallic sandwich panels subject to underwater blast respond in a manner dependent on the relative timescales for water cavitation, core crushing, and structural response in bending. This article examines the response to impulses representative of an (especially relevant) domain: wherein the water cavitates before the core crushes. In some cases, core crushing ceases before the overall structural deformation is complete, leading to what is termed strong-core response. In other situations, core crushing continues beyond the stage at which the dry-face of the sandwich panel ceases to deform, a behavior that is known as weak-core response. It is known that weak-core response provides superior panel performance in terms of three performance metrics: the back-face deflection, the tearing susceptibility of the faces and the loads transmitted to the supports. The relevant regime of behavior is determined by the magnitude of the transmitted impulse from the water, the relative strength of the core, and the aspect ratio of the panel, so that a panel must be designed carefully against a known threat to achieve optimal performance. This paper initiates the development of a map of response for sandwich panels having I-core geometry, delineating strong, weak and other behavior in terms of some of the design parameters mentioned above. The effect of fluid – structure interaction is included in the simulations, and these results are contrasted with those in which fluid – structure interaction is omitted and an initial impulse is instead given to the wet-face of the panel.
In-situ studies of the TGO growth stresses and the martensitic transformation in the B2 phase in commercial Pt-modified NiAl and NiCoCrAlY bond coat alloys
Authors: Hovis D. , Hu L. , Reddy A. , Heuer A. H. , Paulikas A. P. , Veal B. W.
Published: January 2008

Oxide growth stresses were measured in situ at 1100 °C on commercial Pt-modified NiAl and NiCoCrAlY bond coat alloys using synchrotron X-rays. Measurements were taken on samples that had no preoxidation, as well as on samples that had experienced 24 one-hour thermal exposures at 1150 °C, a condition known to induce rumpling in the Pt-modified NiAl alloy, but not in the NiCoCrAlY alloy. The NiCoCrAlY alloy showed continuous stress relaxation under all conditions, whereas the Pt-modified NiAl alloys would typically stabilize at a fixed (often non-zero) stress suggesting a higher creep strength in the “Thermally Grown Oxide” on the latter alloy, though the precise behavior was dependent on initial surface preparation. The formation of martensite in the Pt-modified NiAl alloys was also observed upon cooling and occurred at temperatures below 200 °C for all of the samples observed. Based on existing models, this M
s temperature is too low to account for the rumpling observed in these alloys.
High temperature creep of La-monazite
Authors: Berbon M. , Davis J. B. , Marshall D. B. , Housley R. M. , Morgan P. E. D.
Published: January 2008

Compressive creep of La-monazite is investigated in the temperature range 1100 °C to 1500 °C. The study includes both high-purity single-phase material and material with excess phosphorus located in amorphous grain boundary phases. The results indicate that the presence of small amounts of excess P in polycrystalline LaPO4has a large effect on microstructural stability and creep at high temperature. Materials with La/P ratio close to unity (within ∼500 ppm) show little grain growth at temperatures up to 1400 °C and deform by creep at rates similar to those of alumina and zirconia, with stress exponent ∼1. Materials containing excess P (as little as ∼1 %) show more rapid grain growth, higher creep rates, and cavitation during creep. The results are compared with creep rates of other refractory oxides and oxide fibers. Implications for the behavior of oxide composites containing La-monazite are considered.
Thermal-elastic response of marble polycrystals: Influence of grain orientation configuration
Authors: Saylor David M. , Fuller Edwin R. , Weiss Thomas
Published: January 2008

Two-dimensional, microstructure-based finite element simulations were used to elucidate the influence of grain orientation configuration on the thermal-elastic response of polycrystalline ceramic materials. The two main constituent minerals of marbles, calcite and dolomite, were considered. The crystallographic configuration of the grains is described in terms of the distribution of grain orientations and grain-boundary misorientations. To probe the influence of grain orientation configuration, we first generated the geometry of a hypothetical microstructure. Next, crystallographic orientations were assigned to each grain in the microstructure such that the grain orientations and grain-boundary misorientations matched predefined distributions. By varying the predefined distributions, we generated 45 unique microstructures covering a wide range of crystallographic configurations. After assigning thermal-elastic properties to each structure, corresponding to either calcite or dolomite, finite-element simulations were performed. The simulations demonstrated that both the orientation and misorientation distributions have a substantial impact on the thermal-elastic response of microstructures with the same material properties: varying the crystallographic configuration results in variations of stored elastic strain energy density from 10 kJ m−3to 39 kJ m−3for a 100 °C temperature change. Further, the ratio of the bulk coefficient of thermal expansion in the two principal directions varies from − 0.17 to 1.46. Surprisingly, the grain-boundary misorientations alone had a substantial impact on the thermal-elastic response of the system. By simply rearranging a fixed set of crystallographic orientations to obtain different nearest-neighbor misorientation configurations, we observed variations in strain energy density from 10 kJ m−3to 39 kJ m−3and variations in thermal expansion ratio from 0.06 to 0.90. The results suggest that to predict accurately the thermal-elastic response of polycrystalline ceramics, it is critical to consider both the distribution of grain-boundary misorientations as well as the distribution of grain orientations.
Adhesion of the γ-Ni(Al)/α-Al2O3 interface: a first-principles assessment
Authors: Smith John R. , Jiang Yong , Evans Anthony G.
Published: January 2008

We assess density functional theory studies of the effects of interfacial stoichiometry, Al activity, S segregation and Hf doping on the adhesion of the γ-Ni(Al)/α-Al2O3 interface. Computations of the Al activity in γ-Ni(Al) and of the interfacial phase diagram between 1300 and 1600 K suggest that the interface phase is Al-rich, but close to the boundary with the stoichiometric phase. We reveal that the Al-rich phase has significantly stronger adhesion than the stoichiometric phase and that S substantially decreases the adhesion of both. We demonstrate that doping with Hf yields a substantial improvement in adhesion, manifest in three ways: (i) It can pin S in bulk γ-Ni(Al), even up to 1600 K. (ii) It segregates and, once there, can strengthen the relatively weak stoichiometric interface (attaining a work of separation comparable to that for the strong Al-rich interface). (iii) It has the potential to displace S from interstitial interface sites.
Phase stability of thermal barrier oxides: A comparative study of Y and Yb additions
Authors: Cairney Julie M. , Rebollo Noemi R. , Rühle Manfred , Levi Carlos G.
Published: January 2008

The maximum operating temperature of conventional thermal barrier coatings based on yttria-stabilized zirconia is ultimately limited by de-stabilization of the “non-transformable” t phase, rendering it susceptible to the monoclinic transformation upon cooling. Investigations into alternative thermal barrier oxide compositions suggest that Yb offers superior t stability compared with Y, Sc and larger rare earth cations at the same concentration. The present study sheds light on this behavior by comparing the microstructure evolution of specimens with 7.6 and 11.4 % MO1.5(M = Y or Yb) heat treated at 1450 °C for times up to 512 h. X-ray diffractometry and transmission electron microscopy revealed that the onset of partitioning occurs at short times but then the compositions of the phases evolve slowly over time until sufficient stabilizer is depleted from the t phase to render it transformable. Substitution of Yb for Y delays the onset of monoclinic formation. Differences in the transformation behavior of the Y and Yb rich phases on cooling provide new insight and suggest refinements to the current thermodynamic models for the binary ZrO2– MO1.5systems are needed.
Automated Text Message–Based Program and Use of Acute Health Care Resources After Hospital Discharge
Authors: Bressman Eric , Long Judith A. , Burke Robert E. , Ahn Aiden , Honig Katherine , Zee Jarcy , McGlaughlin Nancy , Balachandran Mohan , Asch David A. , Morgan Anna U.
Published: April 2024

Importance

Postdischarge outreach from the primary care practice is an important component of transitional care support. The most common method of contact is via telephone call, but calls are labor intensive and therefore limited in scope.

Objective

To test whether a 30-day automated texting program to support primary care patients after hospital discharge reduces acute care revisits.

Design, Setting, and Participants

A 2-arm randomized clinical trial was conducted from March 29, 2022, through January 5, 2023, at 30 primary care practices within a single academic health system in Philadelphia, Pennsylvania. Patients were followed up for 60 days after discharge. Investigators were blinded to assignment, but patients and practice staff were not. Participants included established patients of the study practices who were aged 18 years or older, discharged from an acute care hospitalization, and considered medium to high risk for adverse health events by a health system risk score. All analyses were conducted using an intention-to-treat approach.

Intervention

Patients in the intervention group received automated check-in text messages from their primary care practice on a tapering schedule for 30 days following discharge. Any needs identified by the automated messaging platform were escalated to practice staff for follow-up via an electronic medical record inbox. Patients in the control group received a standard transitional care management telephone call from their practice within 2 business days of discharge.

Main Outcomes and Measures

The primary study outcome was any acute care revisit (readmission or emergency department visit) within 30 days of discharge.

Results

Of the 4736 participants, 2824 (59.6%) were female; the mean (SD) age was 65.4 (16.5) years. The mean (SD) length of index hospital stay was 5.5 (7.9) days. A total of 2352 patients were randomized to the intervention arm and 2384 were randomized to the control arm. There were 557 (23.4%) acute care revisits in the control group and 561 (23.9%) in the intervention group within 30 days of discharge (risk ratio, 1.02; 95% CI, 0.92-1.13). Among the patients in the intervention arm, 79.5% answered at least 1 message and 41.9% had at least 1 need identified.

Conclusions and Relevance

In this randomized clinical trial of a 30-day postdischarge automated texting program, there was no significant reduction in acute care revisits.

Trial Registration

ClinicalTrials.gov Identifier: NCT05245773
7T MRI detects widespread brain iron deposition in neuroferritinopathy
Authors: Murley Alexander G. , Rua Catarina , Biggs Heather , Rodgers Christopher T. , Matys Tomasz , van den Ameele Jelle , Horvath Rita , Chinnery Patrick F.
Published: April 2024

Neuroferritinopathy is a disorder of neurodegeneration with brain iron accumulation that has no proven disease‐modifying treatments. Clinical trials require biomarkers of iron deposition. We examined brain iron accumulation in one presymptomatic FTL mutation carrier, two individuals with neuroferritinopathy and one healthy control using ultra‐high‐field 7T MRI. There was increased magnetic susceptibility, suggestive of iron deposition, in superficial and deep gray matter in both presymptomatic and symptomatic neuroferritinopathy. Cavitation of the putamen and globus pallidus increased with disease stage and at follow up. The widespread brain iron deposition in presymptomatic and early disease provides an opportunity for monitoring disease‐modifying intervention.
Direct Laser Processing and Functionalizing PI/PDMS Composites for an On‐Demand, Programmable, Recyclable Device Platform
Authors: Zhu Jia , Xiao Yang , Zhang Xianzhe , Tong Yao , Li Jiaying , Meng Ke , Zhang Yingying , Li Jiuqiang , Xing Chenghao , Zhang Senhao , Bao Benkun , Yang Hongbo , Gao Min , Pan Taisong , Liu Shangbin , Lorestani Farnaz , Cheng Huanyu , Lin Yuan
Published: April 2024

Skin‐interfaced high‐sensitive biosensing systems to detect electrophysiological and biochemical signals have shown great potential in personal health monitoring and disease management. However, the integration of 3D porous nanostructures for improved sensitivity and various functional composites for signal transduction/processing/transmission often relies on different materials and complex fabrication processes, leading to weak interfaces prone to failure upon fatigue or mechanical deformations. The integrated system also needs additional adhesive to strongly conform to the human skin, which can also cause irritation, alignment issues, and motion artifacts. This work introduces a skin‐attachable, reprogrammable, multifunctional, adhesive device patch fabricated by simple and low‐cost laser scribing of an adhesive composite with polyimide powders and amine‐based ethoxylated polyethylenimine dispersed in the silicone elastomer. The obtained laser‐induced graphene in the adhesive composite can be further selectively functionalized with conductive nanomaterials or enzymes for enhanced electrical conductivity or selective sensing of various sweat biomarkers. The possible combination of the sensors for real‐time biofluid analysis and electrophysiological signal monitoring with RF energy harvesting and communication promises a standalone stretchable adhesive device platform based on the same material system and fabrication process.
In Situ Chemical Modulation of Graphitization Degree of Carbon Fibers and Its Potassium Storage Mechanism
Authors: Xiong Shuangsheng , Wu Qi , Gao Yuan , Li Zhiping , Wang Chen , Wang Shuo , Li Zheng , Hou Li , Gao Faming
Published: April 2024

Graphite is considered to be the most auspicious anode candidate for potassium ion batteries. However, the inferior rate performances and cycling stability restrict its practical applications. Few studies have investigated the modulating the graphitization degree of graphitic materials. Herein, a nitrogen‐doped carbon‐coated carbon fiber composite with tunable graphitization (CNF@NC) through etching growth, in‐situ oxidative polymerization, and subsequent carbonization process is reported. The prepared CNF@NC with abundant electrochemical active sites and a rapid K+/electron transfer pathway, can effectively shorten the K+ transfer distance and promote the rapid insertion/removal of K+. Amorphous domains and short‐range curved graphite layers can provide ample mitigation spaces for K+ storage, alleviating the volume expansion of the highly graphitized CNF during repeated K+ insertion/de‐intercalation. As expected, the CNF@NC‐5 electrode presents a high initial coulombic efficiency (ICE) of 69.3%, an unprecedented reversible volumetric capacity of 510.2 mA h cm−3 at 0.1 A g−1 after 100 cycles with the mass‐capacity of 294.9 mA h g−1. The K+ storage mechanism and reaction kinetic analysis are studied by combining in‐situ analysis and first‐principles calculation. It manifests that the K+ storage mechanism in CNF@NC‐5 is an adsorption‐insertion‐insertion mechanism (i.e., the “1+2” model). The solid electrolyte interphase (SEI) film forming is also detected.