bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Stresses and Forces in Selected I‐Bars Using the Finite Element Method
Authors: Naik Preeti R. , Duncanson Manville G. , Mitchell Donald L. , Wiebelt Frank J. , Johnson Dean L. , Ghosh Joydeep 
Published: March 2005

Purpose Three‐dimensional models of half‐round, tapered and full‐round, untapered I‐bar clasps of varying configurations and material properties were constructed. The purpose of this study was to examine the stresses and reaction forces produced within each model upon deflection to 0.01 in (0.254 mm), 0.02 in (0.508 mm), and 0.03 in (0.762 mm) at 1 mm from the tip using the finite element method.Materials and Methods Three‐dimensional computer models of half‐round and full‐round clasps were constructed using solid eight‐node brick elements. The half‐round, tapered I‐bar clasp model was 2.4 and 1.4 mm in diameter at the base and tip, respectively. The full‐round, tapered I‐bar clasp model was 1 mm in diameter. Three design groups were created for each clasp form. Group A had 25% of the total length in the straight anchor end of the I‐bar clasp, B had 35%, and C had 50%. All models were 31 mm in length and had a radius of curvature of 5 mm. Different material properties were incorporated into the models. Each model was deflected at a point 1 mm from the tip to 0.01 in (0.254 mm), 0.02 in (0.508 mm), and 0.03 in (0.762 mm).Results The stresses and forces produced as a result of the deflection applied to each clasp were viewed and displayed graphically. The maximum von Mises stresses in megapascals and the reaction force in newtons (N) were recorded. Stresses varied in each clasp in the range of 0 to 154.3 MPa for the half‐round, tapered I‐bar clasp models, and 0 to 100.9 MPa for the full‐round I‐bar clasp models at 0.01‐in deflection. Reaction force measured near the tip of the clasp models was between 1.60 N and 6.31 N for the half‐round, and between 0.22 N to 2.13 N for the full‐round I‐bar clasp models. For all clasps studied, as the deflection increased, the location of stress within each group remained the same regardless of the material properties; however, the stress and force values increased linearly.Conclusions The location of maximum stress varied with the length of the anchor portion of the clasps studied. Maximum stresses were located on the flat side of the half‐round, tapered I‐bar clasp model.
Predoctoral Fixed Prosthodontics Curriculum Survey
Authors: Petropoulos Vicki C. , Weintraub Annette , Weintraub Gerald S. 
Published: March 2005

Purpose In 1996, a survey of American dental schools was conducted. The purpose of the survey was to determine the curricular structure, techniques taught, and materials used in predoctoral fixed prosthodontics courses.Materials and Methods The survey was mailed to the course directors of predoctoral fixed prosthodontic programs at 53 American dental schools. Of these, 42 schools returned the completed survey, resulting in a response rate of 79%. The mean, median, and the range of responses were computed where applicable.Results The results from this survey show that the mean student‐to‐faculty ratio in the preclinical course was 11:1, with a median of 10:1 and a range of 5:1 to 25:1. The mean number of laboratory clock hours was 164, with a median of 148 and a range of 81 to 288. The mean number of lecture hours reported was 42, with a median of 35 and a range of 20 to 80. Fifty‐five percent of the schools used the Hanau semiadjustable articulator. The most commonly used provisional technique was the thermoplastic custom external surface form (44%). The finish line of choice for the full metal restoration was the chamfer placed circumferentially (74%). The finish line of choice for the porcelain‐fused‐to‐metal restoration was the shoulder placed facially and the chamfer placed lingually (38%).Conclusions Predoctoral fixed prosthodontics education and technical experience varies from school to school, yet a large percentage of schools agree on certain topics.
Working Times and Dimensional Accuracy of the One‐Step Putty/Wash Impression Technique
Authors: Richards Mark W. , Zeiaei Saeid , Bagby Michael D. , Okubo Scott , Soltani Jamshid 
Published: March 2005

Purpose Using the one‐step polyvinyl siloxane impression technique, this study compared the effect of putty material working time on the dimensional accuracy of recovered improved stone casts.Materials and Methods An acrylic resin master cast was fabricated with embedded reference points to enable both horizontal and vertical measurements. Four commercially available polyvinyl siloxane impression putties with light body washes were evaluated: 1) Extrude (Kerr), 2) Cutter (Coltere), 3) Express (3M), and 4) Reprosil (Caulk). Each putty was mixed by hand for 30 seconds, placed in a plastic stock tray, and seated on the master cast at 0, 30, 60, 90, and 120 seconds after mixing (N = 100, n = 5). The impressions were poured in improved stone, and vertical and horizontal measurements were made to 0.001 mm between reference points on recovered casts using an optical traveling microscope. ANOVA (p .05) was used to compare vertical and horizontal measurements to master cast dimensions.Results No statistically significant difference was found among casts for all materials and time periods tested. When horizontal measurement ranges were evaluated, Extrude casts exhibited the widest range of measurement, especially when the trays were seated at 90 and 120 seconds. When vertical measurement ranges were evaluated, Express casts at 120 seconds exhibited the widest range.Conclusions A high range of variability in vertical and horizontal dimensions occurred at the later time periods, especially for Extrude and Express casts. As a result of rapid polymerization and poor flow properties of putty materials, the impression tray should be seated within 60 seconds after putty mixing to reduce dimensional variability of recovered casts.
Current Methods of Finish‐Line Exposure by Practicing Prosthodontists
Authors: Hansen Paul A. , Tira Daniel E. , Barlow Jeff 
Published: March 2005

PurposeThe purpose of this study was to survey members of The American College of Prosthodontists to evaluate current methods of finish‐line exposure. In addition, frequency of use of epinephrine compounds and observed side effects were assessed.Materials and MethodsA questionnaire was mailed to the 2,436 members of The American College of Prosthodontists. Group differences were evaluated using x2 analysis.ResultsCompleted questionnaires were returned by 1,246 prosthodontists, which is a return rate of 51%. Ninety‐eight percent of respondent prosthodontists use retraction cord, and 48% use a double‐cord technique. Plain cord is the most commonly used cord (44%), followed by aluminum chloride‐impregnated cord (18%), and epinephrine‐impregnated cord (14%). Nine hundred one respondents (81%) soak the cord before placing it in the gingival sulcus. The most common medicament for soaking the cords is buffered aluminum chloride (55%). Side effects to epinephrine were reported by 387 respondents (33%), with the most common side effect reported being increased pulse rate, followed by anxiety. Approximately one quarter (24%) of the prosthodontists surveyed had observed side effects to chemical agents other than epinephrine.ConclusionsProsthodontists throughout the country use many different techniques and agents to expose finish lines. No statistically significant differences (p > .05) were found between year of specialty training completion groups with respect to retraction cord use. Copper bands are used significantly more frequently (p < .05) in the northwest region of the United States than elsewhere.
Infrared Gold Alloy Brazing on Titanium and Ti‐6Al‐4V Alloy Surfaces and its Application to Removable Prosthodontics
Authors: Wakabayashi Noriyuki , Ai Minoru , Iijima Kazunori , Takada Yukyo , Okuno Osamu 
Published: March 2005

PurposeThis study investigated the area size of the flow of a gold braze alloy on commercially pure titanium and Ti‐6AI‐4V alloy plates, and elemental composition at the interface was determined. In the second part of this study, the tensile strengths of titanium plates brazed using a gold alloy were investigated.Materials and MethodsChips of Type IV gold alloy and silver braze alloys were melted onto commercially pure titanium and Ti‐6AI‐4V surfaces in a dental infrared radiation unit. Flow area of each braze alloy was measured using a digital image analyzer. Tensile specimens (n = 5) were also prepared by infrared brazing using the braze alloys. Five specimens for each combination of the two titanium plates and the two braze alloys were subjected to tensile loading using a Universal testing machine. Electronprobe microanalysis of x‐rays at cross‐section of the brazed joints to determine elemental composition across the interface, as well as scanning electron microscopic observation at the fracture surfaces, were also conducted.ResultsThe braze alloys flowed well and spread over the Ti and Ti‐6AI‐4V plates. Braze alloy type significantly influenced flow, and the gold alloy flowed less on the titanium materials. The mean tensile strengths of Ti and Ti‐6AI‐4V plates brazed using the gold braze alloy were 219 MPa and 417 MPa, respectively. The fracture surfaces of Ti‐6AI‐4V specimens with the gold braze alloy exhibited typical ductile behavior. Ti with the same braze alloy showed brittle surfaces. A greater concentration of Cu was found at the Ti with gold braze interface.ConclusionThe flow and the tensile strength of the gold alloy coating on titanium surface by means of an infrared brazing is adequate for dental use.
Dental Burs—What Bur for Which Application? A Survey of Dental Schools
Authors: Siegel Sharon Crane , von Fraunhofer Joseph Anthony 
Published: March 2005

PurposeThe purpose of this study was to survey North American dental schools regarding recommendations for rotary instrumentation for fixed prosthodontic and operative procedures at the predoctoral and postgraduate level.Materials and MethodsA 25‐question survey was sent to 64 North American dental schools, of which 15 questions specifically related to rotary instrument recommendations. One questionnaire was addressed to the individual at each school having administrative responsibility for teaching tooth preparation techniques. A high response rate was assured by follow‐up telephone calls and faxes. The distributions of bur recommendations for both predoctoral and advanced prosthodontic programs were analyzed by chi‐squared tests at an a priori α= 0.05.ResultsCompleted surveys were received from 58 of 64 dental schools, a response rate >90%. Medium grit burs predominate in predoctoral education for gross tooth reduction for fixed prosthodontics, whereas coarse grit burs predominate at the graduate level (p < .05). The use of the diamond bur alone predominates for axial wall refinement, whereas the use of carbide burs or carbide burs in combination with diamond burs prevails for marginal refinement (p < .05). In predoctoral operative dentistry, recommendations for cavity outline form were similar at all dental schools (p > .05) and were principally tungsten carbide (WC) burs. Carbide burs are the instrument of choice for internal walls, but the WC bur alone or in combination with diamond burs is preferred for refining composite margins (p < .05).ConclusionsThere is a broad consensus within North American dental schools on rotary instrumentation used by dental students. There is a greater use of coarser grit burs for gross tooth reduction in fixed prosthodontics at the postgraduate than predoctoral level.
A normalization strategy applied to HiCEP (an AFLP-based expression profiling) analysis: Toward the strict alignment of valid fragments across electrophoretic patterns
Authors: Kadota Koji , Fukumura Ryutaro , Rodrigue Joseph J , Araki Ryoko , Abe Masumi 
Published: March 2005

Abstract
Background
Gene expression analysis based on comparison of electrophoretic patterns is strongly dependent on the accuracy of DNA fragment sizing. The current normalization strategy based on molecular weight markers has limited accuracy because marker peaks are often masked by intense peaks nearby. Cumulative errors in fragment lengths cause problems in the alignment of same-length fragments across different electropherograms, especially for small fragments (< 100 bp). For accurate comparison of electrophoretic patterns, further inspection and normalization of electrophoretic data after fragment sizing by conventional strategies is needed.

Results
Here we describe a method for the normalization of a set of time-course electrophoretic data to be compared. The method uses Gaussian curves fitted to the complex peak mixtures in each electropherogram. It searches for target ranges for which patterns are dissimilar to the other patterns (called "dissimilar ranges") and for references (a kind of mean or typical pattern) in the set of resultant approximate patterns. It then constructs the optimal normalized pattern whose correlation coefficient against the reference in the range achieves the highest value among various combinations of candidates. We applied the procedure to time-course electrophoretic data produced by HiCEP, an AFLP-based expression profiling method which can detect a slight expression change in DNA fragments. We obtained dissimilar ranges whose electrophoretic patterns were obviously different from the reference and as expected, most of the fragments in the detected ranges were short (< 100 bp). The normalized electrophoretic patterns also agreed well with reference patterns.

Conclusion
The normalization strategy presented here demonstrates the importance of pre-processing before electrophoretic signal comparison, and we anticipate its usefulness especially for temporal expression analysis by the electrophoretic method.
Quantitative inference of dynamic regulatory pathways via microarray data
Authors: Chang Wen-Chieh , Li Chang-Wei , Chen Bor-Sen 
Published: March 2005

Abstract
Background
The cellular signaling pathway (network) is one of the main topics of organismic investigations. The intracellular interactions between genes in a signaling pathway are considered as the foundation of functional genomics. Thus, what genes and how much they influence each other through transcriptional binding or physical interactions are essential problems. Under the synchronous measures of gene expression via a microarray chip, an amount of dynamic information is embedded and remains to be discovered. Using a systematically dynamic modeling approach, we explore the causal relationship among genes in cellular signaling pathways from the system biology approach.

Results
In this study, a second-order dynamic model is developed to describe the regulatory mechanism of a target gene from the upstream causality point of view. From the expression profile and dynamic model of a target gene, we can estimate its upstream regulatory function. According to this upstream regulatory function, we would deduce the upstream regulatory genes with their regulatory abilities and activation delays, and then link up a regulatory pathway. Iteratively, these regulatory genes are considered as target genes to trace back their upstream regulatory genes. Then we could construct the regulatory pathway (or network) to the genome wide. In short, we can infer the genetic regulatory pathways from gene-expression profiles quantitatively, which can confirm some doubted paths or seek some unknown paths in a regulatory pathway (network). Finally, the proposed approach is validated by randomly reshuffling the time order of microarray data.

Conclusion
We focus our algorithm on the inference of regulatory abilities of the identified causal genes, and how much delay before they regulate the downstream genes. With this information, a regulatory pathway would be built up using microarray data. In the present study, two signaling pathways, i.e. circadian regulatory pathway in Arabidopsis thaliana and metabolic shift pathway from fermentation to respiration in yeast Saccharomyces cerevisiae, are reconstructed using microarray data to evaluate the performance of our proposed method. In the circadian regulatory pathway, we identified mainly the interactions between the biological clock and the photoperiodic genes consistent with the known regulatory mechanisms. We also discovered the now less-known regulations between crytochrome and phytochrome. In the metabolic shift pathway, the casual relationship of enzymatic genes could be detected properly.
Inclusion of Scar/WAVE3 in a similar complex to Scar/WAVE1 and 2
Authors: Stovold Craig F , Millard Thomas H , Machesky Laura M 
Published: March 2005

Abstract
Background
The Scar/WAVE family of proteins mediates signals to actin assembly by direct activation of the Arp2/3 complex. These proteins have been characterised as major regulators of lamellipodia formation downstream of Rac activation and as members of large protein complexes.

Results
We have investigated the interactions of the three human Scar/WAVE isoforms with several previously described binding partners for Scar/WAVE 1 or 2. We find that all three Scar/WAVE isoforms behave similarly and are likely to participate in the same kinds of protein complexes that regulate actin assembly.

Conclusion
Differences between Scar/WAVE proteins are therefore likely to be at the level of tissue distribution or subtle differences in the affinity for specific binding partners.
cAMP controls cytosolic Ca2+ levels in Dictyostelium discoideum
Authors: Lusche Daniel F , Bezares-Roder Karen , Happle Kathrin , Schlatterer Christina 
Published: March 2005

Abstract
Background
Differentiating Dictyostelium discoideum amoebae respond upon cAMP-stimulation with an increase in the cytosolic free Ca2+ concentration ([Ca2+]i) that is composed of liberation of stored Ca2+ and extracellular Ca2+-influx. In this study we investigated whether intracellular cAMP is involved in the control of [Ca2+]i.

Results
We analyzed Ca2+-fluxes in a mutant that is devoid of the main cAMP-phosphodiesterase (PDE) RegA and displays an altered cAMP metabolism. In suspensions of developing cells cAMP-activated influx of extracellular Ca2+ was reduced as compared to wild type. Yet, single cell [Ca2+]i-imaging of regA- amoebae revealed a cAMP-induced [Ca2+]i increase even in the absence of extracellular Ca2+. The cytosolic presence of the cAMP PDE inhibitor 3-isobutyl-1-methylxanthine (IBMX) induced elevated basal [Ca2+]i in both, mutant and wild type cells. Under this condition wild type cells displayed cAMP-activated [Ca2+]i-transients also in nominally Ca2+-free medium. In the mutant strain the amplitude of light scattering oscillations and of accompanying cAMP oscillations were strongly reduced to almost basal levels. In addition, chemotactic performance during challenge with a cAMP-filled glass capillary was altered by EGTA-incubation. Cells were more sensitive to EGTA treatment than wild type: already at 2 mM EGTA only small pseudopods were extended and chemotactic speed was reduced.

Conclusion
We conclude that there is a link between the second messengers cAMP and Ca2+. cAMP-dependent protein kinase (PKA) could provide for this link as a membrane-permeable PKA-activator also increased basal [Ca2+]i of regA- cells. Intracellular cAMP levels control [Ca2+]i by regulating Ca2+-fluxes of stores which in turn affect Ca2+-influx, light scattering oscillations and chemotactic performance.
Genome-scale reconstruction of the metabolic network in Staphylococcus aureus N315: an initial draft to the two-dimensional annotation
Authors: Becker Scott A , Palsson Bernhard Ø 
Published: March 2005

Abstract

Background
Several strains of bacteria have sequenced and annotated genomes, which have been used in conjunction with biochemical and physiological data to reconstruct genome-scale metabolic networks. Such reconstruction amounts to a two-dimensional annotation of the genome. These networks have been analyzed with a constraint-based formalism and a variety of biologically meaningful results have emerged. Staphylococcus aureus is a pathogenic bacterium that has evolved resistance to many antibiotics, representing a significant health care concern. We present the first manually curated elementally and charge balanced genome-scale reconstruction and model of S. aureus' metabolic networks and compute some of its properties.

Results
We reconstructed a genome-scale metabolic network of S. aureus strain N315. This reconstruction, termed i SB619, consists of 619 genes that catalyze 640 metabolic reactions. For 91% of the reactions, open reading frames are explicitly linked to proteins and to the reaction. All but three of the metabolic reactions are both charge and elementally balanced. The reaction list is the most complete to date for this pathogen. When the capabilities of the reconstructed network were analyzed in the context of maximal growth, we formed hypotheses regarding growth requirements, the efficiency of growth on different carbon sources, and potential drug targets. These hypotheses can be tested experimentally and the data gathered can be used to improve subsequent versions of the reconstruction.

Conclusion
iSB619 represents comprehensive biochemically and genetically structured information about the metabolism of S. aureus to date. The reconstructed metabolic network can be used to predict cellular phenotypes and thus advance our understanding of a troublesome pathogen.
Elevated creatine kinase activity in primary hepatocellular carcinoma
Authors: Meffert Georg , Gellerich Frank N , Margreiter Raimund , Wyss Markus 
Published: March 2005

Abstract
Background
Inconsistent findings have been reported on the occurrence and relevance of creatine kinase (CK) isoenzymes in mammalian liver cells. Part of this confusion might be due to induction of CK expression during metabolic and energetic stress.

Methods
The specific activities and isoenzyme patterns of CK and adenylate kinase (AdK) were analysed in pathological liver tissue of patients undergoing orthotopic liver transplantation.

Results
The brain-type, cytosolic BB-CK isoenzyme was detected in all liver specimens analysed. Conversely, CK activity was strongly increased and a mitochondrial CK (Mi-CK) isoenzyme was detected only in tissue samples of two primary hepatocellular carcinomas (HCCs).

Conclusion
The findings do not support significant expression of CK in normal liver and most liver pathologies. Instead, many of the previous misconceptions in this field can be explained by interference from AdK isoenzymes. Moreover, the data suggest a possible interplay between p53 mutations, HCC, CK expression, and the growth-inhibitory effects of cyclocreatine in HCC. These results, if confirmed, could provide important hints at improved therapies and cures for HCC.