bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stress-reduced Direct Composites for the Restoration of Structurally Compromised Teeth: Fiber Design According to the “Wallpapering” Technique
Authors: Deliperi S , Alleman D , Rudo D 
Published: May 2017

SUMMARYPurpose:The purpose of this work was to present a restoration technique based on an understanding of the biomechanical properties of the dentinoenamel complex (DEC) and the physical-mechanical properties of the resin-based composite including the stress generated from both polymerization shrinkage and occlusal forces.Technique Summary:The DEC is a functional interphase that provides crack tip shielding; the DEC should be preserved during restorative procedures. Dentists can design the strategic placement of restorative materials into the cavity to both resist the mode of failure and mimic the performance characteristics of the intact natural tooth. The term “wallpapering” describes a concept of covering the cavity walls with overlapping closely adapted pieces of Leno weaved ultra-high-molecular-weight polyethylene (LWUHMWPE) ribbons. The key for success is that the ribbons are adapted and polymerized as closely as possible against the contours of residual tooth substrate. The resulting thin bond line between the fibers and the tooth structure creates a “bond zone” that is more resistant to failing due to the intrinsic stress and energy absorbing mechanism of the LWUHMWPE ribbons. The formation of defects and voids, from which crack propagation may start, is also reduced. The fibers' tight adaptation to tooth structure allows a dramatic decrease of the composite volume between the tooth structure and the fiber, thus protecting the residual weakened walls from both the stress from polymerization shrinkage and the occlusal load.Conclusion:By using a similar approach, fiber-reinforced stress-reduced direct composite restorations may be performed in the restoration of structurally compromised vital and nonvital teeth.
Comparison of Effectiveness and Sensitivity Using Two In-Office Bleaching Protocols for a 6% Hydrogen Peroxide Gel in a Randomized Clinical Trial
Authors: Vildósola P , Vera F , Ramírez J , Rencoret J , Pretel H , Oliveira OB , Tonetto M , Martín J , Fernández E 
Published: May 2017

SUMMARY

Objective:
The aim of this blinded and randomized clinical trial was to compare two application protocols (one 36-minute application vs three 12-minute applications). We then assessed the effectiveness of the bleaching and any increase in sensitivity that was induced by bleaching via a split-mouth design.

Methods and Materials:
Thirty patients were treated. One group had a half arch of teeth treated with a traditional application protocol (group A: 3 × 12 minutes for two sessions). The other received an abbreviated protocol (group B: 1 × 36 minutes over two sessions). Two sessions were appointed with a two-day interval between them. The tooth color was registered at each session, as well as one week and one month after completing the treatment via a spectrophotometer. This measured L*, a*, and b*. This was also evaluated subjectively using the VITA classical A1-D4 guide and VITA Bleachedguide 3D-MASTER. Tooth sensitivity was registered according to the visual analogue scale (VAS) scale. Tooth color variation and sensitivity were compared between groups.

Results:
Both treatments changed tooth color vs baseline. The ΔE* = 5.71 ± 2.62 in group A, and ΔE* = 4.93 ± 2.09 in group B one month after completing the bleaching (p=0.20). No statistical differences were seen via subjective evaluations. There were no differences in tooth sensitivity between the groups. The absolute risk of sensitivity reported for both groups was 6.25% (p=0.298). The intensity by VAS was mild (p=1.00).

Conclusions:
We used hydrogen peroxide (6%) that was light activated with a hybrid LED/laser and two different protocols (one 36-minute application vs three 12-minute applications each for two sessions). These approaches were equally effective. There were no differences in absolute risk of sensitivity; both groups reported mild sensitivity.
Effect of Endocrown Pulp Chamber Extension Depth on Molar Fracture Resistance
Authors: Hayes A , Duvall N , Wajdowicz M , Roberts H 
Published: May 2017

SUMMARY

Purpose:
The purpose of this study was to evaluate the effect of endocrown pulp chamber extension on mandibular molar fracture resistance.

Methods and Materials:
A total of 36 recently extracted mandibular third molars of approximate equal size were sectioned at the facial lingual height of contour followed by endodontic access into the pulp chamber. The specimens were then randomly divided into three groups (n=12) and pulpal and root canal contents removed. Pulp chamber floors were established at 2, 3, and 4 mm from the occlusal table using a three-step etch-and-rinse adhesive and a flowable resin composite. The prepared specimens were then embedded in auto-polymerizing denture base resin with surface area available for adhesive bonding determined using a digital recording microscope. Specimens were restored using a standardized template with a chairside computer-aided design/computer-aided manufacturing unit with the endocrown milled from a lithium disilicate glass–ceramic material. Restoration parameters of occlusal table anatomy and thickness were standardized with the only parameter difference being the pulp chamber extension depth. The endocrown restorations were luted with a self-adhesive resin luting agent and tested to failure after 24 hours on a universal testing machine, with force applied to the facial cusps at a 45° angle to the long axis of the tooth. The failure load was converted into stress for each specimen using the available surface area for bonding. Mean failure load and stress among the three groups was first subjected to the Shapiro-Wilk and Bartlett tests and then analyzed with an analysis of variance with the Tukey post hoc test at a 95% confidence level (p=0.05).

Results:
The 2- and 4-mm chamber extension groups demonstrated the highest fracture resistance stress, with the 3-mm group similar to the 2-mm group. The 3- and 4-mm chamber extension group specimens demonstrated nearly universal catastrophic tooth fracture, whereas half the 2-mm chamber extension group displayed nonrestorable root fractures.

Conclusions:
Under the conditions of this study, mandibular molars restored with the endocrown technique with 2- and 4-mm pulp chamber extensions displayed greater tooth fracture resistance force as well as stress. All groups demonstrated a high number of catastrophic fractures, but these results may not be clinically significant because the fracture force results are higher than normal reported values of masticatory function.
An Electrophoretic Study of LDH-Isozyme Distribution in Developing Embryonic and Adult Tissues of the Toad Bufo arabicus
Authors: Ambusaidi Intisar , Ba-Omar Taher , Al-Bahri Saif , Al-Shihi Aisha 
Published: May 2017

Lactate (LDH) dehydrogenases were studied by electrophoresis to investigate the possibility of isozymic differences in different stages and organs of B. arabicus embryos, tadpoles and adults. The expression pattern of lactate dehydrogenase (LDH) isozymes was analysed using nondenaturing discontinuous polyacrylamide gel electrophoresis (PAGE). Five LDH isozymes were observed in five different adult tissues. The most cathodal isozyme LDH-5 (A4) showed the strongest activity. All embryonic stages tested displayed the anodic isozymes first. Four LDH isozymes were present in the stages 1-16 (fertilized egg-tail bud stage). The first appearance of the fifth isozyme was detected in stage 17 when the muscular response started. This isozyme showed gradual increase in intensity from stage 17 to stage 43.
Multiphase Mineral Inclusions in Ferrikaersutite Megacrysts : Implications for Postmagmatic Alteration of the Kaersutite Host
Authors: Nasir Sobhi 
Published: May 2017

Primary and secondary multiphase mineral inclusions, without preserved fluid are found in ferrikaersutite megacrysts from the Cenozoic Harrat Ash Sham Volcanic Field in ٍSyria. Mineral phases in the inclusions are magnetite, hematite, pseudobrookite and pyrrhotite. The kaersutite megacrysts formed from a hydrous basanitic melt at depth. Silicate minerals in the inclusions are olivine, plagioclase, phlogopite, hornblende, clino- and orthopyroxene. These silicate minerals crystallized from melt penetration and infillings of veins and fractures in the kaersutite. Magnetite and pyrrhotite inclusion formed through magmatic crystallization which was followed by low temperature alteration and re-equilibration. Late stage near-surface alteration resulted in the formation of hematite, limonite and fine-grained weathering products which comprise high-Fe-Si-, Si-Mg-Al-, Si-Fe-Al-, Si-Al- and Si-Ti-Al-Fe-Ca-rich alterations. The composition of these late stage alteration products was governed by low-temperature post-magmatic alteration of kaersutite along cleavage planes and fractures.
Convective Hydromagentic Slip Flow with Variable Properties Due to a Porous Rotating Disk
Authors: Rahman Mohammad M. 
Published: May 2017

In this paper we investigate convective heat transfer characteristics of steady hydromagnetic slip flow over a porous rotating disk taken into account the temperature dependent density, viscosity and thermal conductivity in the presence of Hall current, viscous dissipation and Joule heating. Using von-Karman similarity transformations we reduce the governing equations for flow and heat transfer into a system of ordinary differential equations which are highly nonlinear and coupled. The resulting nondimensional equations are solved numerically by applying Nachtsheim-Swigert iteration technique. The results show that when modeling a thermal boundary layer, with temperature dependent fluid properties, consideration of Prandtl number as constant within the boundary layer, produces unrealistic results. therefore Therefore it must be treated as variable throughout the boundary layer. Results also show that the slip factor significantly controls the flow and heat transfer characteristics.
A Galerkin Method for a Gaseous Ignition Model
Authors: Salman M. , Kim Jintae 
Published: May 2017

We consider a Galerkin procedure to solve a parabolic integrodifferential equation that arises in a gas combustion model. This model has been proposed by Kassoy and Poland, and subsequently analyzed by Bebernes, Eberly and Bressan. The problem is formulated in the variational form. In order to estimate the error, some intermediate projection has been employed. Under certain conditions on the given data, the error estimate has been obtained. A fully descretized version by using an extrapolated Crank-Nicolson method has been applied and the order of convergence derived.
Dihedral Groups as Epimorphic Images of Some Fibonacci Groups
Authors: Umar Abdullahi , Ali Bashir 
Published: May 2017

The Fibonacci groups are deﬁned by the presentation where , and all subscripts are assumed to be reduced modulo . In this paper we give an alternative proof that for , , and are all inﬁnite by establishing a morphism (or group homomorphism) onto the dihedral group for all .
The effect of starvation on the liver of Aphanius dispar (Pisces; Cyprinodontidae): A microscopic study
Authors: Ba-Omar Taher A. , Al-Amri Mariam , Al-Belushi Jameela , Victor Reginald 
Published: May 2017

Stress due to starvation is not an uncommon phenomenon in fresh-and brackish water fish living in arid environments. This study, a part of a larger investigation on the effects of stress due to starvation on the organ systems of Aphanius dispar, a cyprinodont fish in Oman, reports on the histopathological changes in the liver, using light and transmission electron microscopy. The hepatocytes showed structural and ultrastructural changes in response to 24, 48, 72 and 96 hours of starvation. The hepatocytes of the starved fish groups were characterized by a reduction in the size of their cells and their nuclei, chromatin condensation, loss of stored glycogen, large lipid droplets, wide intercellular spaces and the variable sizes of their mitochondria. Swirls of smooth endoplasmic reticulum (SER) were seen in some of the starved fish, which may indicate their involvement in lipid metabolism and the breakdown of glycogen. This paper makes a further contribution to the understanding of the physiology of fish in arid zones.
A Terbium Sensitized Luminescence Method for the Assay of Flubiprofen in Pharmaceutical Formulations
Authors: Al-Kindy Salma M.Z. , Al-Ghazali Arwa , Suliman Fakhr Eldin O. , Al-Lawati Haidar A.J. 
Published: May 2017

A sensitive time-resolved luminescence method for the determination of flubiprofen (FLP) in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb3+ ) by the formation of a ternary complex with FLP in the presence of 4,7 diphenyl 1,10 phenanthroline (DPP) as co-ligand, and Tween-20 as surfactant. The signal for Tb-FLP-DPP was monitored at λex = 285 nm and λem = 552 nm. Optimum conditions for the formation of the complex in an aqueous system were TRIS buffer, pH 8.0, DPP (2.5Å~10−7 M), Tween-20 (0.30%) and 4Å~10-5 mol L-1 of Tb3+ which allowed the determination of 20–1000 ng mL-1 of FLP with a limit of detection (LOD) of 10 ng mL-1 . The relative standard deviations of the method ranged between 0.6 and 1.4% indicating excellent reproducibility of the method. The proposed method was successfully applied for the assays of FLP in pharmaceutical formulations and spiked tap water samples with average recoveries of 87% – 95%.
Detection of Unlabeled Genetically Modified Soybean in the Omani Market
Authors: Al-Sadqi Nabila , Alansari Aliya S. 
Published: May 2017

This study aimed to screen for products containing Genetically Modified (GM) food in the Omani market using detection methods for the presence of Roundup Ready Soybean, Bt176 and MON810 maize in food products and to quantify it in positive samples using real time Polymerase Chain Reaction (PCR). A total of 100 food samples were collected randomly from markets in Oman. Out of 59 samples, 8 (13.5%) were successfully amplified with the maize plant specific PCR. GM screening showed negative for all samples, which indicated low or no GM maize in the samples tested. Out of 57 soy containing samples, 40 (70%) were successfully amplified by the soybean plant specific PCR. Six samples out of the 40 (15%) were found positive for GM using P35S-cf3/P35S-cr4 and HA-nos118-f/HA-nos118-r, primer pairs and using GMO5/GMO9 and GMO7/GMO8 primer pairs for specific detection of Roundup Ready Soybean. Real time PCR (TaqMan™ system) was carried out for the positive Roundup Ready Soybean samples and results showed that 2 out of the positive GM soy samples contained more than 5%; a Soy Formula for Infants (imported) sample contained 21% GM soybean and raw soybean seeds (imported in bulk amounts and packed in Oman) contained 88% GM soybean. The results demonstrate for the first time the presence of GM-soy in food products in the Omani market, reinforcing the need for the use of qualitative and quantitative methods for GM detection in food products.
Symmetry of the Pyritohedron and Lattices
Authors: Koca Nazife O. , Al-Mukhaini Aida Y. , Koca Mehmet , Al-Qanobi Amal J. 
Published: May 2017

The pyritohedron consisting of twelve identical but non regular pentagonal faces and its dual pseudoicosahedron that possess the pyritohedral (Th) symmetry play an essential role in understanding the crystallographic structures with the pyritohedral symmetry. The pyritohedral symmetry takes a simpler form in terms of quaternionic representation. We discuss the 3D crystals with the pyritohedral symmetry which can be derived from the Coxeter-Dynkin diagram of D3.
Synthesis of a Uniformly Spaced Array with Symmetric Amplitude Excitation by a Weighted Least-Square Method
Authors: Jervase J.A. , Zabalawi I.H. 
Published: May 2017

A new, non-iterative technique for synthesizing equispaced linear arrays with symmetric excitation is proposed. The methods is on the computation of an eigenvector of an appropriate real, Symmetric and positive-definite matrix. This technique can be used to determine, given a n complete description of the desired radiation pattern, the array excitation coefficients . These derived excitation will produce, either exactly or approximately, the wanted antenna radiation pattern, depending on its complexity and the number of my elements. A number of design examples are presented to illustrate the practicality and the potential of the proposed method.
Measurements of RF Radiation in the Vicinity of FM and TV Broadcasting Stations
Authors: Al-Ruwais Abdulaziz S. 
Published: May 2017

This paper provides measurements of power density around an FM and VHF-TV broadcasting station and its variation with distance. The maximum measured value was about 2.4 mW/cm2 at a height of 2 meters above ground level while the average value was fluctuating around 1 mW/cm2. It was found that the measured power density increases with height above ground and it reaches about 3.5 mW/cm2 at a height of about 15 meters at a location of about 400 meters from the station. At a nearer distance of 185 meters from the tower another measurement was taken at a height of 18 meters, the power density increased to 41 mW/cm2.
Simple Formulae for Estimating the Depth and Dimension of Some Geological Bodies From Gravity Anomalies
Authors: Arafin Sayyadul 
Published: May 2017

A simple method for determining the depth and radius of some simple geological bodies such as a sphere and a horizontal cylinder is presented. The method utilizes all of the data points to calculate the body parameters. The depth is estimated from the mean of the depths determined from various fractions of the maximum anomaly and their corresponding widths. The radii of the two bodies are calculated from the areas under the respective gravity profiles. Additionally , the radial symmetry of the gravity anomaly due to a sphere has been utilized to calculate the excess mass from a single profile. The radius determined from the excess mass is independent of depth estimate. This method of determining the radius is more robust than the one based on calculating the area. An error analysis showing the effects of truncation and zero-level errors on the estimated radius is also discussed.
Deregulation of Electricity Supply Industry in Oman
Authors: Al-Maghderi Hamed S. , Ramsay Bruce 
Published: May 2017

This paper examines the opportunities available and the conditions needed for the deregulation of the Electricity Supply Industry (ESI), with particular reference to the Sultanate of Oman. The paper highlights the general issues of regulation required to encourage competition in the ESI. After that, the discussion focuses on regulation methods in the privatized ESI by describing the regulators control through price caps setting for regulatees, the conduct regulation process, the rate of return regulation setting, and the spot market (the pool) contract. Finally, the prospects of restructuring and privatizing the ESI in the Sultanate of Oman are examined by reviewing the current structure of the industry and government objectives in deregulation of the electricity sector as well as the regulation framework.
Intelligent Techniques for Power Systems Vulnerability Assessment
Authors: El-Sharkawi Mohamed A. 
Published: May 2017

With power grids considered national security matters, the reliable operation of the system is of top priority to utilities. This concern is amplified by the utility’s deregulation, which increases the system’s openness while simultaneously decreasing the applied degree of control. Vulnerability Assessment (VA) deals with the power system’s ability to continue to provide service in case of an unforeseen catastrophic contingency. Such contingencies may include unauthorized tripping, breaks in communication links, sabotage or intrusion by external agents, human errors, natural calamities and faults. These contingencies could lead to a disruption of service to part or all of the system. The service disruption is known as outage or blackout. The paper outlines an approach by which feature extraction and boundary tracking can be implemented to achieve on line vulnerability assessment.
Surface Preparation of InAs (110) Using Atomic Hydrogen
Authors: Veal T.D. , McConville C.F. , Al-Harthi S.H. 
Published: May 2017

Atomic hydrogen cleaning has been used to produce structurally and electronically damage-free InAs(110) surfaces. X-ray photoelectron spectroscopy (XPS) was used to obtain chemical composition and chemical state information about the surface, before and after the removal of the atmospheric contamination. Low energy electron diffraction (LEED) and high-resolution electron-energy-loss spectroscopy (HREELS) were also used, respectively, to determine the surface reconstruction and degree of surface ordering, and to probe the adsorbed contaminant vibrational modes and the collective excitations of the clean surface. Clean, ordered and stoichiometric InAs(110)-(1×1) surfaces were obtained by exposure to thermally generated atomic hydrogen at a substrate temperature as low as 400ºC. Semi-classical dielectric theory analysis of HREEL spectra of the phonon and plasmon excitations of the clean surface indicate that no electronic damage or dopant passivation were induced by the surface preparation method.
Regression Estimator Using Double Ranked Set Sampling
Authors: Samawi Hani M. , Tawalbeh Eman M. 
Published: May 2017

The performance of a regression estimator based on the double ranked set sample (DRSS) scheme, introduced by Al-Saleh and Al-Kadiri (2000), is investigated when the mean of the auxiliary variable X is unknown. Our primary analysis and simulation indicates that using the DRSS regression estimator for estimating the population mean substantially increases relative efficiency compared to using regression estimator based on simple random sampling (SRS) or ranked set sampling (RSS) (Yu and Lam, 1997) regression estimator. Moreover, the regression estimator using DRSS is also more efficient than the naïve estimators of the population mean using SRS, RSS (when the correlation coefficient is at least 0.4) and DRSS for high correlation coefficient (at least 0.91.) The theory is illustrated using a real data set of trees.
Analysis of Fire Data in Oman
Authors: Al-Jabri K.S. , Hago A.W. , Alnuaimi A.S. , Al-Mahrooqi S. 
Published: May 2017

The aim of this study is to illustrate the problem of fire accidents in the Sultanate of Oman and their causes in order to find out how the existing data could be used as a base to improve fire resistance, to detect the weak points (vulnerability to fire) in existing structures, and to minimize fire occurrences in places where it is high. This will also provide useful recommendations with regard to fire safety including causes, people’s awareness and education, etc. Fire data in Oman were collected from two sources: The Directorate General of Civil Defence (Public Relations Department) and Sultan Qaboos University library. The collected data represent the number of fires in Oman during the last decade. It also includes fire distribution by type and averages. The analysis shows that there is a linear increase in the number of fire accidents in the last decade with time. Many factors are included as potential sources, which are explained in the paper, and suggestions are made for possible control.