bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrosilanes as Reducing Reagents of Copper Salts into Copper Metal Particles under Remarkably Mild Conditions
Authors: Takahashi Masaki , Kamada Jun , Iwata Kenji , Goto Kenichi , Watanabe Hiroshi , Tamai Shoji
Published: January 2008

Copper nanoparticles were synthesized using hydrosilanes as a reducing agent. The reaction smoothly occurred under remarkably mild conditions, i.e., room temperature. This reaction depended on the counter anions of the copper salts and the structure of the hydrosilanes, and their role is discussed.
Multimetallic Bifunctional Asymmetric Catalysis Based on Proximity Effect Control
Authors: Matsunaga Shigeki , Shibasaki Masakatsu
Published: January 2008

Design and applications of multimetallic bifunctional asymmetric catalysts based on the proximity-effect-control concept are described. Suitable design of chiral ligands and selection of metals were important to realize cooperative bimetallic catalysis. Homo-multimetallic complexes, using linked-BINOLs (Zn, In, Y, and La), as well as hetero-multimetallic complexes, using a dinucleating Schiff base, BINOL, and pybox (Cu–Sm, La–Li, and Y–Li), were developed for asymmetric direct aldol reactions, Michael reactions, direct Mannich-type reactions, nitro-Mannich-type reaction, aza-Michael reactions, kinetic resolution of tert-nitroaldols, and cyanation reactions. Synergistic effects of two or more metals played a key role in promoting the reactions in high reactivity and enantioselectivity.
Theoretical Studies on Electronic Structures and Chemical Indices of the Active Site of Oxygenated and Deoxygenated Hemerythrin
Authors: Takano Yu , Isobe Hiroshi , Yamaguchi Kizashi
Published: January 2008

Hemerythrin (Hr) is an oxygen-transport protein that includes a binuclear iron active site, which is found in marine invertebrates. We investigated the origin of the magnetic couplings, the nature of the chemical bond, and the mechanism of the dioxygen binding of Hr using an appropriate theoretical method and realistic models. First, we selected the appropriate functional of DFT; spin-polarized Becke’s half and half LYP (UB2LYP) showed reasonably good agreement with the experimental values. Secondly, in order to elucidate the origin of the magnetic couplings and understand the nature of the chemical bond, we estimated a range of chemical indices using natural orbitals obtained at the UB2LYP level. The results indicate that the origin of the antiferromagnetic coupling for Hr is the σ- and π-type orbital interactions via weak Fe–μO conjugation (σ- and π-type superexchange interactions) and that the difference in the strength of the dσ–pσ and dπ–pπ interactions of the diiron core in the active site of Hr is responsible for the difference in the magnetic coupling constants between oxygenated and deoxygenated Hr. Finally, using the Mulliken charge-transfer theory, we analyzed the ionization potentials of molecular oxygen and Hr. We concluded that the dioxygen binding in Hr would proceed via a two-step electron-transfer mechanism.
C. FALLUOMINI, Der sogenannte Codex Carolinus von Wolfenbüttel (Codex Guelferbytanus 64 Weissenburgensis). Mit besonderer Berücksichtigung der gotisch-lateinischen Blätter
Authors: Crisci Edoardo
Published: January 2008

Nella produzione libraria del mondo antico e medievale, i codici palinsesti rappresentano un settore tanto interessante quanto, ancora, relativamente poco indagato. La stratificazione, per lo più casuale, di tipologie testuali e grafiche diverse in un unico codice-contenitore (la cui stessa ragion d'essere si propone, per la singolare natura del prodotto librario, come problematica e significativa) offre a specialisti di ambiti diversi – filologi, paleografi, codicologi – un ampio ventaglio di prospettive d' indagine e di itinerari di ricerca. Come uno scavo stratigrafico – in cui ciascun elemento va riportato alla luce, studiato, contestualizzato, preservato nella sua originaria integrità – così l'indagine condotta sui codici palinsesti deve costantemente conciliare la natura frammentaria dei materiali riutilizzati (testuali, grafici, codicologici) con la nuova unità libraria che ne è derivata, cogliendo, proprio nella compresenza di elementi vari ed eterogenei, gli indizi utili alla ricostruzione di scenari culturali più vasti e articolati. Dapprima indagati sotto il profilo esclusivamente testuale – con atteggiamento non scevro da una certa ‘filologica’ superiorità nei confronti di prodotti librari ritenuti comunque di seconda scelta (si pensi, per esempio, ai lavori di Angelo Mai, intesi esclusivamente al recupero di testi antichi ritenuti particolarmente significativi, con procedimenti per lo più devastanti per la conservazione e l'integrità dei reperti), solo in tempi più recenti i palinsesti sono stati recuperati alla dimensione di uno studio globale, non più solo filologico, ma anche grafico e codicologico, che prescinda dalla rarità dei testi conservati.
TH. K. THOMAS, Late antique Egyptian funerary sculpture. Images for this world and the next
Authors: Grossmann Peter
Published: January 2008

Das Buch ist in drei Teile zu je zwei Kapiteln gegliedert: 1. Spätantike ägyptische Grabskulptur; 2. Monumente dieser Welt; 3. Vorstellungen von der nächsten Welt. Die Kapitel selbst sind durchgezählt.
J. M. FEATHERSTONE, Theodore Metochites's poems ‘To Himself’. Introduction, text and translation
Authors: Jeffreys Elizabeth
Published: January 2008

The hexameter poems of Theodore Metochites are perhaps the most determinedly baroque of all Byzantine literary productions to have survived. The tortuous constructions of Metochites' prose rhetoric are transmuted into his rather imprecise concept of the hexameter, with a vocabulary that is ostensibly Homeric but in fact ranges over the whole spectrum of Greek literature, with not a few coinages of his own. The twenty poems, in just over 9,000 lines, were written probably towards the end of his period in high office; several clearly date from the period immediately before his fall from power in 1328, with others written in the years between his return from exile to his beloved monastery of the Chora and his death in 1332. The topics treated by Metochites range from solipsistic musings on his youth and the troubles that afflicted his old age to bombastic funerary memorials. Although the poems are preserved in several manuscripts, it has been demonstrated (by Ihor Ševčenko) that Par.Gr. 1776 stands at the head of the tradition. It is in a format similar to that, for example, of another luxury copy of Metochites' own works, Vindob. Phil. Gr. 95, while the corrections to the verses have been shown to be in the hand of Metochites himself.
CH. STAVRAKOS, Die byzantinischen Bleisiegel mit Familiennamen aus der Sammlung des Numismatischen Museums Athen
Authors: Sode Claudia
Published: January 2008

Das Numismatische Museum Athen besitzt mit über 2000 Exemplaren eine der wichtigsten Sammlungen byzantinischer Siegel. Die hier zu besprechende Arbeit, die auf Anregung von Werner Seibt entstanden ist, bietet eine Neuedition der byzantinischen Bleisiegel mit Familiennamen aus den Beständen des Athener Museums, die in der Διεθνης Έϕημεϱις της Νομισματιϰης Άϱχαιολογίας (Journal international d'archéologie numismatique) in den Jahren 1902 bis 1907 erstmals von K. Konstantopulos publiziert wurden. Der Katalog von Konstantopulos, der alle bis 1905 in das Numismatische Museum Athen aufgenommenen byzantinischen Bleisiegel umfaßt, wurde 1917 als selbständige Publikation nachgedruckt. Nicht berücksichtigt werden vom Autor dagegen etwa die Siegel aus der Sammlung A. Stamules, die dieser im Jahre 1924 dem Museum schenkte und die 1930 ebenfalls von Konstantopulos publiziert wurden, sowie weitere Siegel aus den Athener Beständen, wenngleich der Titel des Buches erwarten läßt, daß sämliche byzantinischen Bleisiegel mit Familiennamen aus der Sammlung des Numismatischen Museums Athen erfaßt sind.
Maximi Confessoris Liber Asceticus eed. P. VAN DEUN adiectis tribus interpretationibus latinis sat antiquis editis a Steven Gysens
Authors: von Stockhausen Annette
Published: January 2008

Nach der Edition der Expositio in Ps 59 und der Expositio orationis dominicae (P. van Deun [ed.], Maximi Confessoris Opuscula exegetica duo. [CChr.SG, 23.] Turnhout/Leuven 1991.] legt van Deun (D.) mit dem hier anzuzeigenden Band nun den Liber Asceticus des Maximus Confessor (erstmals) in einer kritischen Edition vor.
G. PEERS, Subtle bodies, Representing Angels in Byzantium
Authors: Thümmel Hans Georg
Published: January 2008

Diese überarbeitete Dissertation eines Kunsthistorikers will sich vor allem den Schriftquellen für und gegen Engelsdarstellungen widmen, bezieht freilich auch Denkmäler mit ein. Dahinter steht die Einsicht, daß die gegen christliche Bilder vorgebrachten Argumente zwar insgesamt an der Unmöglichkeit eines Gottesbildes festgemacht sind, daß aber das Engelsbild die Probleme deutlicher zeigt. Konnte beim Gottesbild auf die Inkarnation Christi verwiesen werden, die ihn darstellbar macht (wie auch bei der Gottesmutter und den Heiligen die Darstellbarkeit mit ihrer irdischen Existenz begründet werden konnte), so versagten solche Argumente bei den Bildern von Engeln, die als geistig und körperlos geglaubt wurden. Freilich gibt es hier Differenzierungen, auf die P. hinweist: Als geschaffene Wesen werden sie in ihrer Geistigkeit von der Gottes abgesetzt. Die Arbeit ist eher problemorientiert, als daß sie das Material systematisch erfaßte. Und manches ist nun freilich speziell auf Bilder von Engeln bezogen und auf deren Besonderheit zugeschnitten, was allgemein christliche Kunst betraf.
Beobachtungen zu einigen Textstellen im Geschichtswerk des Niketas Choniates
Authors: Rhoby Andreas
Published: January 2008

Folgende Beobachtungen ergaben sich aus der Lektüre der Χϱονιϰη διήγησις des Niketas Choniates. Es handelt sich um Interpretationen des Inhalts und textkritische Anmerkungen.
Viewing Advertising through the Lens of Faith
Authors: Kelso Tony
Published: January 2008

Various scholars have noted connections between traditional Protestantism and advertising in the United States. Not only did the two institutions inform one another as modern advertising emerged and matured, but, arguably, the two systems also exhibit parallel rhetorical formats and functions today. In this qualitative study, it is suggested that a shift in emphasis, from advertising’s relationship to explicit religion to its interaction with implicit religiosity, could provide fresh insights. This framework was explored through focus group interviews, participant journal entries, and one-on-one, in-depth interviews with Protestants from three mainline congregations. The findings show that some of the participants can, on occasion, touch the spiritual realm through transactions with advertising. Indeed, it is contended that, although they belong to formal religious organizations, these respondents can also engage in practices associated with implicit religion. At the same time, the interviewees also indicated they have little awareness of how advertising perpetuates the economic status quo. Displaying hegemony at work, they are seemingly able to pursue both explicit and implicit religious experiences and support their market-driven culture without bearing significant cognitive dissonance. The paper makes the case that advertising can sometimes function as a vehicle for helping to reconcile this apparent conflict.
English Law as Implicit Religion
Authors: Hanson Sharon
Published: January 2008

This article applies the concept of implicit religion to law in order to give a new understanding of English law: its sacredness and its theology; its organizational structures and its social forms. Having constructed a table of potential elements, illustrating the concept of implicit religion, read against both Christianity and Law, three entries from that table are explored in further detail. Ultimately, the article argues that not only is English law an implicit religion templated by Christianity, but that it contains within itself a sacred paradox, formed by the interaction of its implicit and explicit religious dimensions.
Implicit Religious Assumptions within the Resurgence of Civil Religion in the USA since 9/11
Authors: Swatos, Jr William H.
Published: January 2008

Any number of societal reactions to the attacks of 11 September 2001 could be conceived as theoretical possibilities within the United States. In this article I want to make the argument that what a number of writers, but most notably Robert Bellah, have identified as civil religion in America provided the principal cultural resource that served to reintegrate and unite Americans in a coherent national response to the crisis. This is true because civil religion already existed as a cultural substratum and because it was, in fact, aspects of this very substratum that were under attack in the particular dynamics of these events. The thesis I propose is not a restudy of the civil religion concept qua concept. A variety of such studies have appeared from the 1970s to the 1990s and can be easily consulted by those interested in issues of conceptual development, refinement, elaboration, critique, and so on. I want to take the concept as broadly defined by Bellah, and empirically specified by Ronald Wimberley and colleagues in a series of subsequent investigations, and apply it to understanding the nature, function, and possible outcomes of the American response.
Believe in the Net
Authors: Parna Karen
Published: January 2008

In the course of the 1990s the Internet gave rise to highly optimistic scenarios regarding its significance for humanity. In the media, in the business-guru circuit and in politics, a euphoric discourse emerged that strongly adhered to the

belief that the Internet and related business methods would change the world radically and be the long-awaited vessels of earthly salvation. This paper attempts to account for such belief. It suggests that the trust invested in the extraordinary qualities of the Internet was largely based on the special meaning granted to it, which can be described as sacred. This article looks at the sources of this contemporary manifestation of the sacred and considers how the Internet

became a belief with religious traits. An historical comparison between the Internet craze and the fascination with the telegraph in the nineteenth century will serve to demonstrate that there exists a longer tradition of associating new technologies with the sacred and the transcendent.
Stochastic Fracture Modelling of the Yufutsu Field
Authors: Anraku T. , Namikawa T. , Herring T. , Jenkins I. , Price N. , Trythall R.
Published: January 2008

The Yufutsu field is a fractured granite, gas condensate reservoir, located on Hokkaido island, in the north of Japan. There is minimal primary porosity and secondary porosity consists of fractures. Fractures are categorised into four types according to size (mega, major, minor and halo fractures). Mega fractures govern the flow, while micro fractures govern gas storage. Gas migrated into the reservoir after the fractures were formed.

The field shows abnormal production behaviour, and this paper attempts to characterise production, by the use of 3D-stochastic geological modelling and reservoir simulation. Incorporating all of the effects that were observed from the Yufutsu field into a reservoir model proved to be an extremely complex process.

A three-stage reservoir study was undertaken:

To build a 3D stochastic geological model. Initially small-scale models were built, with both mega and micro fractures modelled stochastically as objects. Effective permeability (matrix + fracture) was calculated across a 200,000 cell single porosity simulation model, along with tracer efflux rates for relative permeability calculations. The above model behaviour was replicated in a 6 cell dual porosity model, which was substituted into the coarser scale single well and full field models.

The resultant methodology used provided accurate and realistic description of the fracture system, which was then used for well planning and production forecasting.
Identification and Implications of Induced Hydraulic Fractures in Waterfloods: Case History HGEU
Authors: Griffin L. G. , Wright C. A , Demetrius S. L. , Blackburn B. D. , Price D. G.
Published: January 2008

In secondary and enhanced oil recovery projects, it is critical to determine if hydraulic fracturing occurs during water injection and, if fracturing occurs, to understand its associated impacts on oil recovery. If hydraulic fracturing occurs under normal injection operating conditions or, if the production and/or injection wells are fracture stimulated, knowing the orientation and dimensions of the created fractures are critical for determining the proper pattern alignment to optimize sweep efficiency. This paper presents the application and results of tiltmeter mapping techniques used at the Howard Glasscock East Unit (HGEU). Tiltmeter mapping was used to determine the existence, orientation, and geometry of created hydraulic fractures, as well as, the dependence of fracture length on the water injection rate. Tiltmeter fracture mapping identified that hydraulic fracturing occurs even at very low water injection rates (less than 250 BWPD) at the HGEU creating significant fractures (exceeding 400 feet of half-length). The mapping also showed that the length of the fractures was relatively rate independent over the range of rates tested. The HGEU waterflood pattern orientation, pattern spacing and injection rate guidelines were established based on these results.
Gas-Well Testing: Changing Requirements, Changing Perspective
Authors: Pridie D. J.
Published: January 2008

In Western Canada at the turn of the century, most gas discoveries are less than 10 106m3 (~3 bcf) in volume and the question has evolved from the simple "At what rate will it flow?" to the complex "How long will it remain commercial?". As a result, reserves measurement and production forecasting have become an integral part of the initial production test. In the planning and fieldwork stages, it is fortunate that a few simple adjustments to accepted testing techniques are all that are required to yield good reserves numbers. In the analysis stage, it has become apparent that pressure responses can be categorized to yield expected production profiles. Some production forecasts depend as much on the profile to be commercial as they do on the reserves. With respect to "rules of thumb", there have grown up some quick formulas for estimating reserves numbers and for forecasting the results of stimulations. The concept of skin factor has metamorphosed in the latter process.
Coiled Tubing Scale Removal of Iron Sulfide - A Case Study of the Kaybob field in Central Alberta
Authors: Bittner S. D. , Zemlak K. R. , Korotash B. D.
Published: January 2008

Iron sulfide scale deposition occurs throughout the Kaybob South field in Central Alberta. The scale typically forms directly on the tubular walls and generally results in corrosion of the metal beneath the scale crystallites. Under normal conditions, iron sulfide is soluble in hydrochloric acid. However, in sour gas and condensate environments, an asphaltene binder forms over the crystallites to limit, if not completely eliminate, the efficiency of chemical removal treatments. In such cases, the scale can only be effectively removed by mechanical means. A number of different methods of scale removal have been attempted, with an inconsistent record of success. For example, on some wells HCl Blends (7%-22% HCl) with xylene have been successful on the first attempt, on other wells this mixture required several attempts, and in some cases this technique resulted in no success. Mechanical options to resolve the problem include a tubing replacement (with an average cost of $150K - $550K CDN depending on completion complexity) or a milling treatment. The milling process, using coiled tubing, a motor and a mill, is costly and carries an element of risk. Well workovers are completed as required in this area on a regular basis - typically one per year.

This case study will define and present the Blaster scale removal system that has been developed to clean tubulars. The techniques have been continually improved and modified since their introduction in January 1998. Amoco Canada participated in the beta test of the system where several modifications to the process were made. Nineteen wells have been completed as part of the test program, the results of which has added valuable data to this case study.

This paper will demonstrate that coiled tubing technology has provided an effective, efficient and economic method of scale removal.
Theoretical Analysis and Design Modification of PDM for Air Drilling
Authors: Samuel G. Robello , Miska Stefan
Published: January 2008

This paper outlines three design modifications of the conventional power section of PDM operating on air. Theoretically, an increase in power output can be achieved by using motor power section with variable cross sectional area. The paper discusses the energy relationships for the various design modifications. Also the paper offers insights to the advantages and disadvantages of various designs.
Efficient Design of Reservoir Simulation Studies for Development and Optimization
Authors: Kalla S. , White C. D.
Published: January 2008

Development studies examine the importance of geologic, engineering, and economic parameters to formulate and optimize production plans. If there are many factors, these studies are prohibitively expensive unless simulation runs are chosen and analyzed efficiently.

Experimental design and response models can improve study efficiency, and have been widely applied in reservoir engineering. To approximate nonlinear oil and gas reservoir responses accurately, designs must consider factors at more than two levels, not just high and low values. However, multilevel designs require many simulations, especially if many factors are being considered. Partial factorial and mixed designs are more efficient than full factorials, but multilevel partial factorial designs are difficult to formulate and have not been used in reservoir engineering.

Orthogonal arrays and nearly orthogonal arrays provide the required design properties and can handle many factors. These arrays span the design space with fewer runs, can be manipulated easily, and are appropriate for computer experiments.

The proposed methods have been applied to a model of a gas well with water coning. Eleven geologic were varied while optimizing three engineering factors (total of fourteen factors). A nearly orthogonal array was specified with three levels for eight factors and four levels for the remaining six geologic and engineering factors. The proposed design required 36 simulations compared to 46 × 38 = 26,873,856 runs for a full factorial design.

Kriged response surfaces can approximate the relationship between the parameters and responses; these are compared to polynomial regression surfaces. Polynomial response surfaces are used to optimize completion length, tubing head pressures, and tubing diameters for a partially penetrating well in a gas reservoir with uncertain properties.

Compared with full and partial factorials, the nearly orthogonal array design improves flexibility, requires fewer simulation runs, and yields more accurate response models. Thus, orthogonal arrays allow more efficient optimization and straightforward sensitivity and uncertainty assessment.
Creating Value by Improving the Operator/Nonoperator Partner Relationship
Authors: van Driel J. P. , Pederson T.
Published: January 2008

Our industry is uniquely characterised by fierce competition to gain access to opportunities such as exploration acreage or participation rights in redevelopment opportunities, and once access is secured cooperation among competitors turned partners is common. In practice, the motivation for the formation of these partnerships is to reduce financial exposure and not to create value. As operators typically assume a dominant role, they drive investment decisions with little, if any, value-creating input from partners. The ultimate development plans therefore may not be attractive to the nonoperating partners, but the alternative of nonparticipation is even worse. These behaviors create a lose-lose situation. For operators, "partner-drag" extends cycle time and increases costs. For nonoperators, value creation opportunities are lost and their control over the future of their investments is less than they are entitled to, based on their equity.

This paper explores some critical questions: Do partnerships create or destroy value? What role should a non-operating partner play in a venture, and what competency does it require to be able to make positive contributions? Should partners focus on errors of omission (i.e., missing high-value opportunities, doing the wrong project) or on errors of commission (i.e., not getting full value from execution, doing the project wrong)? The authors, drawing on Petoro case studies, will share lessons learned and best practices developed from implementing a business model based entirely on creating value as a nonoperating partner. Novel work processes are presented, based on these learnings, that improve the relationship between operators and nonoperating partners from lose-lose to win-win.
Numerical Simulation of Steam Displacement of Oil in Naturally Fractured Reservoirs Using Fully Implicit Compositional Formulation: A Comparative Analysis of the Effects of Capillary and Gravitational Forces in Matrix/Fracture Exchange Term
Authors: Cicek O.
Published: January 2008

A numerical simulator for steam displacement of oil from naturally fractured reservoirs is developed and tested. The three-dimensional and three phase field scale model employs a compositional dual-porosity/dual-permeability mathematical formulation. Capillary, gravitational and viscous forces are accounted for in the mathematical model. Using a fully implicit solution scheme, the model solves for (2nHC+10) primary variables simultaneously, where nHC is the number of hydrocarbon components. All reservoir parameters are formulated as functions of all the primary variables. The model is linearized using Newton-Raphson method, and the system of linear equations is solved by a direct and an iterative solver. The model is verified against the Fourth and Sixth SPE Comparative Solution Projects. The model is highly stable for the studied extremely dynamic and stiff problems, accommodating large time steps with two to three Newtonian iterations. The simulations are carried out up to ten years to test the features of the model for long periods of steam injection in naturally fractured systems.

Fluid exchange between the fracture and the matrix blocks due to the gravitational, capillary and viscous forces is investigated for a range of naturally fractured reservoirs with different matrix block sizes and capillary pressures. Relative effects and relative magnitutes of these acting forces on the displacement of the matrix oil are analysed in these naturally fractured systems undergoing steam injection. This comprehensive and comparative analysis is conducted using different realizations of the studied naturally fractured systems such as the dual-permeability and the dual-porosity models.

The steam injection operations are carried out for long periods of time. The low initial pressures in the studied fractured systems facilitate zooming in on and observing how, in particular, the capillary and gravitational forces work, and testing the model under more strained conditions in a naturally fractured reservoir undergoing a steam injection operation.
Effect of Oil and Flue-Gas Compositions on Oil Recovery in the Flue-Gas/Light-Oil Injection Process
Authors: Shokoya O. S. , Mehta S. A. , Moore R. G. , Maini B.
Published: January 2008

Flue gas injection is becoming more attractive as a feasible and environmentally friendly process for improving oil recovery from light oil reservoirs. When obtained from surface sources, the flue gas process has an added advantage of preventing carbon dioxide (CO2), a greenhouse gas, from being disposed into the atmosphere. Flue gas can also be generated in-situ by the spontaneous ignition of oil when air, a readily available gas, is injected into high temperature, high pressure (light oil) reservoirs. The availability of flue gas and/or air and the observed high oil recovery potential make the flue gas process an economically attractive process. Oil recovery efficiency and displacement characteristics were studied in the laboratory with nitrogen and two flue gas compositions having CO2 content of 16% and 30% and two light oils obtained from two different reservoirs. The recombined light oils were displaced by the flue gases in a 2.44 m long, 5.1 cm diameter Berea sandstone core at irreducible brine saturation. The studies were conducted at reservoir pressures up to 41.58 MPa and temperatures of 80.6°C and 116°C, corresponding to the reservoir temperature of the oils studied. The experimental data was history-matched with a fully compositional simulator and the results show that oil recovery efficiency has a direct relationship to the paraffin and naphthene content of the oil. It was found during the core flood that the displacement of the oil with lower paraffin (higher naphthene) content produced more oil than the displacement with higher paraffin at one pore volume of flue gas injected, even at lower operating pressure.
HNF4α and the Ca-Channel TRPC1 Are Novel Disease Candidate Genes in Diabetic Nephropathy
Authors: Niehof Monika , Borlak Jürgen
Published: January 2008

OBJECTIVE—The nuclear receptor hepatic nuclear factor 4α (HNF4α) is a master regulatory protein and an essential player in the control of a wide range of metabolic processes. Dysfunction of HNF4α is associated with metabolic disorders including diabetes. We were particularly interested in investigating molecular causes associated with diabetic nephropathy.

RESEARCH DESIGN AND METHODS—Novel disease candidate genes were identified by the chromatin immunoprecipitation–cloning assay and by sequencing of immunoprecipitated DNA. Expression of candidate genes was analyzed in kidney and liver of Zucker diabetic fatty (ZDF) and of streptozotocin (STZ)-administered rats and after siRNA-mediated silencing of HNF4α.

RESULTS—We identified the calcium-permeable nonselective transient receptor potential cation channel, subfamily C, member 1 (TRPC1) as a novel HNF4α gene target. Strikingly, TRPC1 is localized on human chromosome 3q22-24, i.e., a region considered to be a hotspot for diabetic nephropathy. We observed a significant reduction of TRPC1 gene expression in kidney and liver of diabetic ZDF and of STZ-administered rats as a result of HNF4α dysfunction. We found HNF4α and TRPC1 protein expression to be repressed in kidneys of diabetic patients diagnosed with nodular glomerulosceloris as evidenced by immunohistochemistry. Finally, siRNA-mediated functional knock down of HNF4α repressed TRPC1 gene expression in cell culture experiments.

CONCLUSIONS—Taken collectively, results obtained from animal studies could be translated to human diabetic nephropathy; there is evidence for a common regulation of HNF4α and TRPC1 in human and rat kidney pathologies. We propose dysregulation of HNF4α and TRPC1 as a possible molecular rationale in diabetic nephropathy.
B-Cells Promote Intra-Islet CD8+ Cytotoxic T-Cell Survival to Enhance Type 1 Diabetes
Authors: Brodie Gillian M. , Wallberg Maja , Santamaria Pere , Wong F. Susan , Green E. Allison
Published: January 2008

OBJECTIVE—To determine the role of B-cells in promoting CD8+ T-cell—mediated β cell destruction in chronically inflamed islets.

RESEARCH DESIGN AND METHODS—RIP-TNFα-NOD mice were crossed to B-cell–deficient NOD mice, and diabetes development was monitored. We used in vitro antigen presentation assays and in vivo administration of bromodeoxyuridine coupled to flow cytometry assays to assess intra-islet T-cell activation in the absence or presence of B-cells. CD4+Foxp3+ activity in the absence or presence of B-cells was tested using in vivo depletion techniques. Cytokine production and apoptosis assays determined the capacity of CD8+ T-cells transform to cytotoxic T-lymphocytes (CTLs) and survive within inflamed islets in the absence or presence of B-cells.

RESULTS—B-cell deficiency significantly delayed diabetes development in chronically inflamed islets. Reintroduction of B-cells incapable of secreting immunoglobulin restored diabetes development. Both CD4+ and CD8+ T-cell activation was unimpaired by B-cell deficiency, and delayed disease was not due to CD4+Foxp3+ T-cell suppression of T-cell responses. Instead, at the CTL transition stage, B-cell deficiency resulted in apoptosis of intra-islet CTLs.

CONCLUSIONS—In inflamed islets, B-cells are central for the efficient intra-islet survival of CTLs, thereby promoting type 1 diabetes development.
COOH-Terminal Clustering of Autoantibody and T-Cell Determinants on the Structure of GAD65 Provide Insights Into the Molecular Basis of Autoreactivity
Authors: Fenalti Gustavo , Hampe Christiane S. , Arafat Yasir , Law Ruby H.P. , Banga J. Paul , Mackay Ian R. , Whisstock James C. , Buckle Ashley M. , Rowley Merrill J.
Published: January 2008

OBJECTIVE—To gain structural insights into the autoantigenic properties of GAD65 in type 1 diabetes, we analyzed experimental epitope mapping data in the context of the recently determined crystal structures of GAD65 and GAD67, to allow “molecular positioning” of epitope sites for B- and T-cell reactivity.

RESEARCH DESIGN AND METHODS—Data were assembled from analysis of reported effects of mutagenesis of GAD65 on its reactivity with a panel of 11 human monoclonal antibodies (mAbs), supplemented by use of recombinant Fab to cross-inhibit reactivity with GAD65 by radioimmunoprecipitation of the same mAbs.

RESULTS—The COOH-terminal region on GAD65 was the major autoantigenic site. B-cell epitopes were distributed within two separate clusters around different faces of the COOH-terminal domain. Inclusion of epitope sites in the pyridoxal phosphate–and NH2-terminal domains was attributed to the juxtaposition of all three domains in the crystal structure. Epitope preferences of different mAbs to GAD65 aligned with different clinical expressions of type 1 diabetes. Epitopes for four of five known reactive T-cell sequences restricted by HLA DRB1*0401 were aligned to solvent-exposed regions of the GAD65 structure and colocalized within the two B-cell epitope clusters. The continuous COOH-terminal epitope region of GAD65 was structurally highly flexible and therefore differed markedly from the equivalent region of GAD67.

CONCLUSIONS—Structural features could explain the differing antigenicity, and perhaps immunogenicity, of GAD65 versus GAD67. The proximity of B- and T-cell epitopes within the GAD65 structure suggests that antigen-antibody complexes may influence antigen processing by accessory cells and thereby T-cell reactivity.
Activation of Central Lactate Metabolism Lowers Glucose Production in Uncontrolled Diabetes and Diet-Induced Insulin Resistance
Authors: Chari Madhu , Lam Carol K.L. , Wang Penny Y.T. , Lam Tony K.T.
Published: January 2008

OBJECTIVE—Hypothalamic lactate metabolism lowers hepatic glucose production and plasma glucose levels in normal rodents. However, it remains unknown whether activation of hypothalamic lactate metabolism lowers glucose production and plasma glucose levels in rodents with diabetes and obesity.

RESEARCH DESIGN AND METHODS—We performed intracerebroventricular (ICV) administration of lactate to enhance central lactate metabolism in 1) early-onset streptozotocin-induced uncontrolled diabetic rodents, 2) experimentally induced hypoinsulinemic normal rodents, and 3) early-onset diet-induced insulin-resistant rodents. Tracer-dilution methodology was used to assess the impact of ICV lactate on the rate of glucose production in all three models.

RESULTS—We first report that in the absence of insulin treatment, ICV lactate administration lowered glucose production and glucose levels in rodents with uncontrolled diabetes. Second, ICV lactate administration lowered glucose production and glucose levels in normal rodents with experimentally induced hypoinsulinemia. Third, and finally, ICV lactate administration lowered glucose production in normal rodents with diet-induced insulin resistance.

CONCLUSIONS—Central lactate metabolism lowered glucose production in uncontrolled diabetic and normal rodents with hypoinsulinemia and in rodents with diet-induced insulin resistance. These data suggest that insulin signaling is not required for central lactate to lower glucose production and that the activation of hypothalamic lactate metabolism could consequently bypass insulin resistance and lower glucose levels in early-onset diabetes and obesity.
Effect of Polishing Techniques and Time on Surface Roughness, Hardness and Microleakage of Resin Composite Restorations
Authors: Venturini D. , Cenci M. S. , Demarco F. F. , Camacho G. B. , Powers J. M.
Published: January 2008

Clinical Relevance

The effects of polishing techniques on surface roughness, microhardness and microleakage of resin composites are material dependent. In general, since immediate polishing has not had a negative influence on the tested properties of the two composites compared to delayed polishing, this procedure could be preferred, reducing the number of clinic sessions and bringing more comfort and satisfaction to the patient.
Effect of Restorative Procedures and Occlusal Loading on Cuspal Deflection
Authors: González-López S. , De Haro-Gasquet F. , Vílchez-Díaz MÁ , Ceballos L. , Bravo M.
Published: January 2008

Clinical Relevance

The progressive elimination of dental tissue, especially removal of marginal ridges and dentin above the pulp chamber and application of increasing occlusal loads, were related to a higher cuspal deflection.
Use of Two Surface Analyzers to Evaluate the Surface Roughness of Four Esthetic Restorative Materials After Polishing
Authors: Joniot S. , Salomon J. P. , Dejou J. , Grégoire G.
Published: January 2008

Clinical Relevance

All esthetic restorative materials do not have the same polishing characteristics. Nanofilled composites and fluid materials containing microfiller give the best surface states. Results with posterior composites and compomers are less effective.
Effect of Different Bur Grinding on the Bond Strength of Self–etching Adhesives
Authors: Semeraro S. , Mezzanzanica D. , Spreafico D. , Gagliani M. , Re D. , Tanaka T. , Sidhu S. K. , Sano H.
Published: January 2008

Clinical Relevance

In some self-etching systems, selecting the proper bur type for cutting dentin is important for improving bond strength.
An Effective Method for Spreading Flowable Composites in Resin-based Restorations
Authors: Abedian B. , Millstein P.
Published: January 2008

Cavity lining with flowable composites has been suggested for better marginal adaptation and a reduction in interfacial stress and post-operative sensitivity. The following in vitro study compares the spreading of flowable composite that lines the inner wall of a test cavity using an explorer and a specially designed smooth, oscillating, off-center rotating bur spun at 300 to 600 rpm. Two commercial flowable materials were used in this study. Results: With use of the rotating bur, a more consistent, uniform cavity lining was achieved. This was not possible using the dental explorer. Conclusion: The specially designed rotating bur provides an effective way for clinicians to form a uniform cavity lining.
Marginal Permeability of Self-etch and Total-etch Adhesive Systems
Authors: Owens B. M. , Johnson W. W. , Harris E. F.
Published: January 2008

Clinical Relevance

Decreased leakage was associated with Adper Scotchbond Multi-Purpose (total etch) and iBond (self-etch) systems in Class V resin composite restorations. All adhesive systems performed best when bonded to enamel compared to dentin surface anatomy. Clinicians should be aware that strict adherence to manufacturer instructions, when using these materials, is of primary importance.
Analysis of Dentinal Stress Distribution of Maxillary Central Incisors Subjected to Various Post-and-core Applications
Authors: Toksavul S. , Zor M. , Toman M. , Güngör M. A. , Nergiz I. , Artunç C.
Published: January 2008

Clinical Relevance

According to FEA analysis, under a simulated occlusal load, the cervical area of endodontically treated and crowned maxillary central incisors was the most stress concentrated area. Zirconia ceramic posts create slightly less dentinal stress concentration than titanium and glass-fiber posts.
The Linear Shrinkage and Microhardness of Packable Composites Polymerized by QTH or PAC Unit
Authors: Park S-H. , Noh B-D. , Cho Y-S. , Kim S-S.
Published: January 2008

Clinical Relevance

When packable composites are cured using the PAC system, 12 seconds of light curing is recommended for shallow cavities that do not exceed 2 mm, and many measures should be applied in order to avoid the clinical complications associated with a rapid cure.
Rehabilitation of an Adolescent with Autosomal Dominant Amelogenesis Imperfecta: Case Report
Authors: Yamaguti P. M. , Acevedo A. C. , de Paula L. M.
Published: January 2008

Clinical Relevance

This case stresses the importance of preventive procedures in the restoration of dentition affected by amelogenesis imperfecta.
Influence of the Finishing Technique on Surface Roughness of Dental Porcelains with Different Microstructures
Authors: Sasahara R. M. C. , Ribeiro F. C. , Cesar P. F. , Yoshimura H. N.
Published: January 2008

Clinical Relevance

After the glaze layer of a ceramic restoration is broken, the clinician should pay attention to the specific porcelain used in the prosthetic work, since the best finishing technique (reglazing versus polishing) depends on the porcelain's characteristics.
Effect of Early Water Exposure on the Strength of Glass Ionomer Restoratives
Authors: Wang X. Y. , Yap A. U. J. , Ngo H. C.
Published: January 2008

Clinical Relevance

Modern day glass ionomer restoratives are not significantly weakened by early water exposure, after initial set.
Influence of Nd:YAG Laser Irradiation on an Adhesive Restorative Procedure
Authors: Franke M. , Taylor A. W. , Lago A. , Fredel M. C.
Published: January 2008

Clinical Relevance

Statistical analysis of the results obtained in this study shows that Nd:YAG laser irradiation on the adhesive system has a significant influence on bond strength to dentin. Bond strength is improved by better adhesive penetration when low energy is applied; whereas, high energy densities have a deleterious effect on the procedure.
A Posterior Composite Case Utilizing the Incremental and Stratified Layering Technique
Authors: Chi H. H.
Published: January 2008

Clinical Relevance

This paper illustrates a technique for placing posterior composites.
Effect of Thermal Cycling on Enamel Bond Strength of Single-step Self-etch Systems
Authors: Amano S. , Yamamoto A. , Tsubota K. , Rikuta A. , Miyazaki M. , Platt J. A. , Moore B. K.
Published: January 2008

Clinical Relevance

After thermal cycling, some recently introduced simplified bonding systems showed no change in enamel bond strengths.
Effect of Blood Contamination with 1-step Self-etching Adhesives on Microtensile Bond Strength to Dentin
Authors: Yoo H. M. , Pereira P. N. R.
Published: January 2008

Clinical Relevance

When using 1-step self-etching adhesive systems, blood contamination significantly decreased bond strength to dentin and should be avoided.
Mercury Exposure in Dental Practice
Authors: Atesagaoglu A. , Omurlu H. , Ozcagli E. , Sardas S. , Ertas N.
Published: January 2008

Clinical Relevance

This study failed to find a correlation between blood mercury levels and cytogenic damage in dentists exposed to mercury vapor below 0.1mg/m3.
Shear Bond Strength of Resin-modified Glass Ionomer Cements to Er:YAG Laser-treated Tooth Structure
Authors: Souza-Gabriel A. E. , Amaral F. L. B. , Pécora J. D. , Palma-Dibb R. G. , Corona S. A. M.
Published: January 2008

Clinical Relevance

Er:YAG laser adversely affected the adhesion of resin-modified glass ionomer cements to tooth structure and cannot be considered an alternative technique to the conventional turbine handpiece.
Comparison of Proximal Contacts of Class II Resin Composite Restorations In Vitro
Authors: Loomans B. A. C. , Opdam N. J. M. , Roeters F. J. M. , Bronkhorst E. M. , Burgersdijk R. C. W.
Published: January 2008

Clinical Relevance

When placing a Class II resin composite restoration, the use of sectional matrix systems and separation rings to obtain tight proximal contacts is recommended.
Microleakage in the Proximal Walls of Direct and Indirect Posterior Resin Slot Restorations
Authors: Fruits T. J. , Knapp J. A. , Khajotia S. S.
Published: January 2008

Clinical Relevance

Evaluation of microleakage in proximal resin restorations in relation to factors such as the type of dentin bonding system and the location of gingival margins may provide information that can aid clinicians in their attempt to reduce the occurrence of microleakage.
In Vitro Hydrolytic Degradation of Composite Quartz Fiber-post Bonds Created by Hydrophilic Silane Couplings
Authors: Monticelli F. , Osorio R. , Toledano M. , Tay F. R. , Ferrari M.
Published: January 2008

Clinical Relevance

Silane-based composite bonds are susceptible to hydrolytic degradation: interfacial water sorption induced by hydrolytic couplings may adversely affect their strength.
Effect of Air-drying Time of Single-application Self-etch Adhesives on Dentin Bond Strength
Authors: Chiba Y. , Yamaguchi K. , Miyazaki M. , Tsubota K. , Takamizawa T. , Moore B. K.
Published: January 2008

Clinical Relevance

The air-drying time of single-step self-etch adhesives was a significant factor influencing dentin bond strengths.
Influence of the Rubber Dam on Proximal Contact Strengths
Authors: Rau P. J. , Pioch T. , Staehle H-J. , Dörfer C. E.
Published: January 2008

Clinical Relevance

The use of a rubber dam results in major effects on proximal contact strengths during treatment, which the dentist should be aware of in order to avoid negative effects on the quality of the restoration.
The Effect of Base Materials with Different Elastic Moduli on the Fracture Loads of Machinable Ceramic Inlays
Authors: Banditmahakun S. , Kuphasuk W. , Kanchanavasita W. , Kuphasuk C.
Published: January 2008

Clinical Relevance

Based on the results of this study, the elastic moduli of base materials had an influence on fracture loads of machinable ceramic inlays. The use of a base material with a high elastic modulus to support a ceramic inlay is recommended.
The Effect of Rubber Dam Placement on the Arterial Oxygen Saturation in Dental Patients
Authors: Goodday R. H. B. , Crocker D. A.
Published: January 2008

Clinical Relevance

Although placement of a rubber dam for operative procedures has the potential to alter airflow through the nasal and oral cavities, it appears not to reduce the arterial blood oxygen level in a healthy patient.
Inhibition of Lesion Progression by the Penetration of Resins In Vitro: Influence of the Application Procedure
Authors: Mueller J. , Meyer-Lueckel H. , Paris S. , Hopfenmuller W. , Kielbassa A. M.
Published: January 2008

Clinical Relevance

The penetration of adhesives into initial enamel demineralization seems to be a promising approach to providing a non-operative treatment regimen for carious lesions.
The Effectiveness of Alumina Powder on Carious Dentin Removal
Authors: Motisuki C. , Lima L. M. , Bronzi E. S. , Spolidorio D. M. P. , Santos-Pinto L.
Published: January 2008

Clinical Relevance

When an air abrasion system is used, 27 and 50 μm aluminum oxide particles remove carious dentin with maximum preservation of sound structure when compared to 125 μm particles.
Influence of Adhesive Systems on Interfacial Dentin Gap Formation In Vitro
Authors: Loguercio A. D. , Reis A. , Bortoli G. , Patzlaft R. , Kenshima S. , Filho L. E. Rodrigues , Accorinte M. L. R. , van Dijken J. W. V.
Published: January 2008

Clinical Relevance

Etch & rinse systems showed better initial interfacial adaptation than self-etch systems. The differences disappeared after 6-months water storage. The thicker the hybrid layer formed by self-etching adhesives, the lower the immediate gap formation.