bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Different Light Curing Units/Modes on the Microleakage of Flowable Composite Resins
Authors: Yazici A. Ruya , Celik Cigdem , Dayangac Berrin , Ozgunaltay Gul 
Published: September 2019

Objectives: The aim of this in vitro study was to evaluate the influence of different light curing
units and modes on microleakage of flowable composite resins.Methods: Eighty Class V cavities were prepared in buccal and lingual surfaces of 40 extracted human premolars with cervical wall located in dentin and the occlusal wall in enamel. These teeth were randomly assigned into two groups (n=20) and restored with different flowable composites; Group I: Esthet-X Flow, Group II: Grandio Flow. Each group was randomly divided into four subgroups; while the samples of the first subgroup were polymerized with conventional Halogen light, the rest of them were polymerized with different curing modes of Light Emitting Diode (LED). The second subgroup was polymerized with fast-curing; the third subgroup with pulse-curing and those of the fourth subgroup with step-curing modes of LED. After the samples were thermocycled and immersed in dye, they were longitudinally sectioned. Dye penetration was assessed under a stereomicroscope. Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests.Results: None of the restorations showed leakage on enamel margins. On dentin margins no significant differences were observed between flowable composite resins polymerized with halogen light (P>.05). While step curing mode of LED presented significant differences between the resins, the difference was insignificant when fast-curing and pulse-curing mode of LED were used. No statistically significant differences were observed between curing units for Esthet-X Flow samples. For Grandio Flow samples, only step-curing mode of LED caused statistically higher leakage scores than halogen and other curing modes of LED (P<.05).Conclusions: The effect of curing units� type and curing mode on flowable composite resin leakage might be material-dependent. (Eur J Dent 2008;2:240-246)
Prevalence of Torus Palatinus in Cappadocia Region Population of Turkey
Authors: Sisman Yildiray , Ertas Elif Tarim , Gokce Cumali , Akgunlu Faruk 
Published: September 2019

ABSTRACTObjectives: The objectives of this study were to determine the prevalence, size, shape and location of the torus palatinus (TP) in dental outpatients in Cappadocia region of Turkey and to investigate the relationship between the findings in relation to age and gender.Methods: The present study included 2660 patients, who attended the Department of Oral Diagnosis and Radiology in the Faculty of Dentistry at Erciyes University for their dental problems between December 2005 and May 2007. The presence or absence of TP was examined by clinical inspection and palpation.Results: The prevalence of TP in our large sample was low (4.1%) in comparison to other Turkish population. It was found to be significantly higher (P<.001) in females (5.7%) than in males (1.8%). Most TP were found in flat shape (62.7%), smaller than 2 cm (75.4%) and located at premolar-molar region (66.4%).Conclusions: This study indicated that the prevalence of TP in Turkish population was low. Our results showed a significant relationship between the occurrence of TP and gender. According to the literature, it was firstly showed that flat TP was the most common type in our large population. (Eur J Dent 2008;2:269-275)
Self-Inflicted Gingival Injury Due to Habitual Fingernail Scratching: A Case Report with a 1-Year Follow Up
Authors: Dilsiz Alparslan , Aydin Tugba 
Published: September 2019

ABSTRACTInjuries to oral soft-tissues can occur due to accidental, iatrogenic, and factitious traumas. Traumatic lesions, whether chemical, physical, or thermal in nature, are among the most common in the mouth. A type of physical injury to the gingival tissues is self-inflicted. Sometimes the lesions are termed gingivitis artefacta. Self-inflicted gingival injuries in children and adolescents can occur as a result of accidental trauma, premeditated infliction, or chronic habits such as fingernail biting, digit sucking, or sucking on objects such as pens, pencils or pacifiers. The purpose of this case report was to illustrate the destructive nature of the habit and to describe the successful treatment of this case. A 14-year-old girl with moderate pain, gingival bleeding and recession in the anterior mandibulary region was admitted to periodontology clinic. Upon questioning, the patient readily admitted traumatizing her gingiva with her fingernail. Treatment consisted of oral hygiene instruction, mechanical debridement, psychological support and surgical periodontal treatment. Postoperatively, complete root coverage, gains in clinical attachment levels, and highly significant increases in the width of keratinized gingiva were observed. This case report shows that it is possible to treat gingival injury and maintain the periodontal health of a patient with destructive habit. Patient compliance, regular dental follow-ups, and psychological support may be useful in stabilizing the periodontal condition of these patients. Dentists must be aware that self-inflicted gingival injury, although thought to be uncommon, is quite widespread. (Eur J Dent 2009;3:150-155)
Cytotoxicity of Mouthrinses on Epithelial Cells by Micronucleus Test
Authors: Erdemir Ebru Olgun , Şengün Abdulkadir , Ülker Mustafa 
Published: September 2019

ABSTRACTObjectives: To determine the cytotoxicity of three commercial mouthrinses Klorhex, Andorex and Tanflex on buccal epithelial cells using micronucleus (MN) test.Materials and Methods: 28 patients with aged 16-24 undergone three mouthrinses’ application were analyzed before and after one week exposure. Physiologic saline was used for the control group. The MN incidence was scored in the buccal epithelial of each participants. The difference in pre- and posttreatment after one week incidence of MN and plaque (PI) and gingival indices (GI) was compared by non-parametric statistical tests.Results: The micronuclei incidence increased in Klorhex, Tanflex and Andorex groups after exposure to mouth rinses (P<.05). But when compared with the control group, there was not any difference between Andorex and control group (P>.05). In the other study groups, MN incidence was significantly increased after 7 days treatment (P<.05). GI scores of all groups were decreased significantly (P<.05). PI scores were decreased only in the Klorhex group (P<.05).Conclusions: Our primary findings support the presence of possible cytotoxic effects of the mouthrinses on gingival epithelial cells. (Eur J Dent 2007;2:80-85)
Rapunzel syndrome – A rare form of trichobezoar: A case report
Authors: L. Thayumanavan , K. Rajkumar , M. Kennan 
Published: September 2019

ABSTRACTHair ball in the GI tract is called trichobezoar and the Rapunzel syndrome is a very rare form of trichobezoar found in patients with psychiatric illness in whom the ingested hair extends from the stomach into the small intestine. Trichotillomania (hair pulling) and trichophagia (chewing of hair) are intrinsic to the development of Rapunzel syndrome. A small number of patients have been reported in whom the gastric trichobezoar has a long tail and extends throughout the small bowel to the cecum. This condition, known as the Rapunzel syndrome, occurs almost exclusively in young girls. We report a case Rapunzel syndrome who presented with history of upper GI obstruction and weight loss. Upper GI endoscopy revealed a large trichobezoar occupying fundus of stomach extending along the whole stomach into duodenum beyond its 3rd part. It was treated successfully with surgery followed by psychiatric consultation. We will review the literature on the subject as well. (J Dig Endosc 2013;4(1):19–21)
International crop trade networks: the impact of shocks and cascades
Authors: Burkholz Rebekka , Schweitzer Frank 
Published: September 2019

Abstract
Analyzing available FAO data from 176 countries over 21 years, we observe an increase of complexity in the international trade of maize, rice, soy, and wheat. A larger number of countries play a role as producers or intermediaries, either for trade or food processing. In consequence, we find that the trade networks become more prone to failure cascades caused by exogenous shocks. In our model, countries compensate for demand deficits by imposing export restrictions. To capture these, we construct higher-order trade dependency networks for the different crops and years. These networks reveal hidden dependencies between countries and provide an estimate of necessary stock reserves to protect countries from cascading export restrictions. They differ substantially from first-order networks that do not take cascading effects into account. We find rice trade most prone to cascading export restrictions. A great number of Asian and African countries are most exposed to cascades. Noticeably, the main suppliers are similar for most of the crops: USA, Canada, Argentina, Brazil, and India. While shocks in the USA mainly affect South America and several Asian countries, the south of Africa is primarily dependent on American and Asian exporters. The north of Africa depends strongly on Europe, in particular via wheat imports.
Cold waves are getting milder in the northern midlatitudes
Authors: van Oldenborgh Geert Jan , Mitchell-Larson Eli , Vecchi Gabriel A , de Vries Hylke , Vautard Robert , Otto Friederike 
Published: September 2019

Abstract
The strong two-day cold wave in the midwestern United States in January 2019 again ignited the discussion as to whether cold waves are getting more severe or not as a result of Arctic amplification due to climate change. Assessing the evolution of cold waves in the northern hemisphere midlatitudes in the observations has been difficult because the variability of cold waves is large compared to anthropogenic warming. In order to detect changes in cold spells, two complementary ways to optimise the signal-to-noise ratio are employed: multi-decadal series at individual stations, and for shorter time periods by using spatially aggregated measures. Global warming is now strong enough to make trends clear at individual stations when considering long enough (>50 yr) records of daily minimum and maximum temperature. Calculating the land area that has temperatures below the 1-in-10 year return value (defined over 1951–1980) enables us to investigate trends over a shorter time horizon. The long-term station data have strong decreases everywhere in the lowest minimum temperature. Warming trends in the lowest maximum temperature are smaller over most of the Northern Hemisphere, with dataset-dependent indications of possible negative trends in parts of the United States and Mexico. Considering the area experiencing cold waves over the last decades, the most notable feature is a sharp decline of this area since the 1980s. The natural variability is still so large that it is possible to arbitrarily select starting dates after the decline for which the trend is slightly positive in smaller regions like North America or Europe. However, these values are within uncertainties compatible with a steady decline and have differing starting dates in North America and Europe. An analysis of the entire northern midlatitudes confirms the steady decrease in severity and frequency of cold waves over the last decades in the observations.
Bending analysis of skew ribbed plates with a meshfree method
Authors: Qin Xia , Liu Shan Shan , Peng Lin-Xin 
Published: September 2019

Abstract
Based on the first - order shear deformation theory (FSDT), a meshless method for solving the free vibration problem of the skew ribbed plates is proposed. The plates and ribs are discretized with a series of points to obtain a meshless model of the ribbed plate by simulating the ribs with beams. The FSDT and the moving least - squares approximation are used to establish the displacement field. The displacement fields of the stiffener can be expressed in terms of the mid-surface displacement of the plate by imposing displacement compatible conditions between the plate and the stiffener. Then the stiffness equation of the entire skew ribbed plate can be derived by superimposing the strain energy of plate and stiffener. And the boundary condition is introduced by the full transformation method. Several examples are calculated, and the results given by the proposed method are compared with those from other researchers or ABAQUS. The results show that the method can effectively analyze the bending problem of the skew ribbed plate, and it avoids redistribution of plate nodes when rib position changes.
Rib layout optimization of stiffened square plates based on a meshfree model and a hybrid genetic algorithm
Authors: Li Linyuan , Peng L X 
Published: September 2019

Abstract
In order to minimize the central deflection of stiffened square plates under different loads, stiffener/rib layout optimization of stiffened plate is studied in the present work based on meshfree method and a hybrid genetic algorithm. The stiffened plates are composed of flat plates and straight beams with constant cross section. In order to combine the flat plates and beams, are introduced. The calculate method of the stiffened plate is the meshfree method, and the ribs can be placed beyond mesh lines. During the entire process of rib layout optimization, no remeshing of the plate is required, which is convenient in programming and cost-efficient in computation. The optimization is carried out through the hybrid genetic algorithm which combines the genetic algorithm (GA) and the controlled random search algorithm. The controlled random search algorithm can effectively shorten the computation time of the genetic algorithm and increase the probability to find the efficient points. The validity and adaptability of the proposed method are tested by calculating several numerical examples.
Stiffness and damping effects of the rhombic piezoelectric stack transducer with a negative capacitance shunt
Authors: Yan B , Zheng W , Zhou S , Wu C 
Published: September 2019

Abstract
The piezoelectric shunt damping (PSD) is widely utilized to control structural vibrations based on its damping performance. Unlike previous studies, this work considers the stiffness and damping effects of a rhombic piezoelectric stack transducer with a negative capacitance shunt. The piezoelectric shunt stiffness (PSS) and the PSD concepts are proposed and theoretically modelled to investigate the stiffness and damping performance. The piezoelectric stack transducer with a negative capacitance can achieve both negative and positive stiffnesses to tune the natural frequency of the host structure. The root locus methods are utilized to judge the stability of the system. Both numerical simulation and experimental results demonstrate that the negative stiffness and the positive stiffness of the system greatly depend on the negative capacitance, while the damping depends on the resistance.
The thermal effect on dynamic characteristics of composite material pipe conveying fluid
Authors: Cai Su , Fang Bo 
Published: September 2019

Abstract
Based on thermoelasticity, the composite material pipe is studied in this paper with the variation of thermal expansion coefficient and temperature. Considering the thermal effect, a model called elastic Bernoulli-Euler beams is developed to analysis the buckling and vibration. The partial differential equations are established by using Hamiltonian principle. The static post-buckling problem is studied by eigenvalue method after Galerkin method. By harmonic balance method, the approximate solution of strong nonlinear vibration is obtained. The effect of thermal effect on vibration is also focused. The simulation shows that the thermal effects make conveyor pipes more vulnerable to instability, and has obvious influence on the dynamic characteristics. The research content is more practical than the dynamic analysis of the conveyor pipe without considering the temperature effect.
Vibration analysis of a rotating axially functionally graded tapered beam with hollow circular cross-section
Authors: Dong Shipeng , Li Liang , Zhang Dingguo , Zhang Yang 
Published: September 2019

Abstract
In this paper, the free vibrations of a rotating axially functionally graded (FG) tapered cantilever beam with hollow circular cross-section attached to a rigid hub are studied. To capture the additional dynamic stiffening terms, the longitudinal shrinkage of the beam is considered. The dynamic governing equations are derived via employing the assumed modes method and Lagrange’s equations. Through ignoring the higher-order quantities, the first order approximate coupling (FOAC) dynamic model can be acquired. Based on the FOAC dynamic model, influences of the angular speed, the taper ratio, the hub radius, the slenderness ratio, and the functionally gradient index on natural frequencies are studied. Frequency veering and mode shape interaction of the system are discussed when the bending-stretching (B-S) mode coupling effect of the beam is considered.
Static and dynamic mechanical properties of impregnated carbon nanotube fiber
Authors: Wan Shan-Xiu , Yang Qing-Sheng 
Published: September 2019

Abstract
Carbon nanotube fiber (CNT fiber) with excellent electrical and mechanical properties, as well as stable thermal and chemical properties has great potential application in areas such as ultra-fine wires, ultra-light cables, sensors, composite materials, energy conversion and electro-actuation. In this paper, the static and dynamic mechanical properties of impregnated CNT fiber were studied through single and cyclic tensile experiments and continuous dynamic analysis (CDA).The dynamic properties of impregnated CNT fiber such as storage and loss modulus was obtained. In addition, the storage modulus and loss modulus of impregnated CNT fiber increases with the increase of loading frequency. The research work in this paper has an important reference value for the engineering applications of impregnated CNT fiber in the fields of sensors and composites.
Design and Analysis of Shape Memory Polymer Mast Base on Numerical Simulation Method
Authors: Liu Shuai , Yang Qing-Sheng 
Published: September 2019

Abstract
As a space deployable structure, the space masts are widely used in the aerospace field. In the article, a new shape memory polymer (SMP) mast structure was designed and the compression folding behaviours of the SMP mast was investigated. The mast can automatic deployment due to the shape recovery characteristics of SMPs. The thermodynamic model of SMPs were realized by the finite element method. The numerical simulation of the fold and deployment process of the SMP mast were carried out, and the geometric parameters (wall thickness) and the influence of temperature on the folding performance of the mast were also investigated. The results contribute to the design and application of novel SMP mast.
Investigation of mechanical properties of additive manufactured graphene-reinforced aluminium composites
Authors: Liu Li-Ya , Yang Qing-Sheng 
Published: September 2019

Abstract
Graphene considered as an ideal reinforcement for metal matrix composites (MMCs) because of its excellent optical, electrical and mechanical properties has important application prospects in materials science, micro-nano processing and so on. Meanwhile, additive manufactured MMCs becomes the hotspot of current research due to the advantages of precise and controllable structure and easy implementation of modularization. In this paper, a two-dimensional rate-dependent crystal plasticity model using the numerical model is developed to simulate the mechanical behaviors of additive manufactured graphene-reinforced aluminium matrix composites (AMCs) under tensile load in a mesoscale. The mechanical properties are described by varying the volume fractions and distribution patterns of graphene. The results verify that graphene is the main load-bearing part of AMCs. The volume fraction and distribution pattern of graphene play an important role in the crystal dislocation strengthening of AMCs. Moreover, it is proved that the additive manufactured graphene-reinforced AMCs have a potential improvement with increased graphene volume fraction and optimized geometric graphene parameters.
The lightweight topology optimization of multi-material structures with displacement constraints
Authors: Dai Zong-Jie , Ye Hong-Ling , Wang Wei-Wei , Sui Yun-Kang 
Published: September 2019

Abstract
Multi-material Topology Optimization is a simulation technique based on the principle of the finite element method which is able to determine the optimal distribution of two or more different materials in combination under thermal and mechanical loads. This paper develops a lightweight topology optimization formulation of multi-material structures considering displacement constraints based on independent, continuous and mapping (ICM) method. Furthermore, explicit expression of optimised formulation is derived, approximations of displacement and weight are given by the first and second order Taylor expansion. And the optimization problem is solved by sequential quadratic programming approach. The feasibility and effectiveness of proposed method are demonstrated by numerical examples. It is found that the best transfer path of load is provided using multi-material topology optimization. The results show that a clear topological structure is obtained and the best transfer path of load is provided after multi-material topology optimization. In addition, under the precondition of satisfying the displacement constraint condition, the weight of the optimized structure based on various materials is lighter. The weight of multi-material topology optimization structure decreases with the increase of displacement constraint. And the optimal topological structure of the multi-material is different with the component materials. Besides, the optimization model established by using the structural performance parameters as a constraint is more reliable and more suitable for practical engineering applications.
Effects of microstructural parameters on phase transition temperature of hydrogels in chemo-mechanical coupling fields
Authors: Li Tao , Yang Qing-Sheng 
Published: September 2019

Abstract
The stability of hydrogels can be considered as the stability of polymer networks of the gels. The external environment can lead to the change of the polymer networks stability and the phase transition of hydrogels occurs. In this paper, a new free density energy function considering the chain entanglements and functionality of junctions is presented via combining Gent hyperelastic model and Edwards-Vilgis slip-link model with Flory-Huggins theory. A numerical method is developed to solve the phase transition temperature of the hydrogels based on the given new free energy function. Influences of four microstructure parameters on phase transition temperature of hydrogels are investigated by taking PNIPAM hydrogel as an example. Analytical results show that the microstructure parameters might affect the phase transition of the hydrogels significantly.