bluuebunny/crossref_metadata_2025 huggingface dataset:
Retrospective 5-Year Analysis of Revision Rate and Functional Outcome of TKA With and Without Patella Implant
Authors: Albrecht Dominique C. , Ottersbach Andreas
Published: May 2016

The aim of this study was to compare a patient cohort after total knee arthroplasty (TKA) in terms of the revision rate and the functional outcome, with and without patella resurfacing. Sixty-six patients (71 TKAs) were implanted with the mobile-bearing knee prosthesis system e.motion UC (Aesculap AG, Tuttlingen, Germany). These patients were divided into 2 groups, 1 of which received primary patella resurfacing (PPR; 51 TKAs) and 1 of which did not (non-PPR; 20 TKAs), with an average follow-up of 65.6 months (±6.9). The cohort was recorded consecutively. The evaluation was performed using the Knee Society Score and selected questions relating to the Knee Injury and Osteoarthritis Outcome Score, as well as with radiographs. Results showed that PPR was no better than non-PPR in terms of functional outcome. Two knees (10%) were revised in the non-PPR group, and 1 knee (1.96%) in the PPR group (not significant). In this cohort, 100% of implants, including the 5 TKAs of patients who did not attend the follow-up examination, had neither explanted nor loosened at the time of follow-up examination. The authors concluded that the revision rate for PPR is slightly lower, and this avoids the need for secondary patella resurfacing. The risk for complications is low, and the functional outcome is comparable. [
Orthopedics
. 2016; 39(3):S31–S35.]
A Low Memory 3D Animation Technology for "Animation Design" Course
Authors: QIN Zhenyan , TAO Zonghua
Published: May 2016

This paper introduces a “low memory” 3D animation design technology teaching system, and fully describes the design requirements, design thought, and main modules of the system. On this basis, an analysis of the teaching process of applying the system in animation design curriculum in universities is made with the method of contrastive teaching experiment. Results show: comparing with traditional multimedia teaching method, the application of “low memory” 3D animation design technology significantly improves the effectiveness of animation design teaching. This teaching method is of prominent innovative value, and worth to be further popularized and applied in teaching.
Principal Proactivity
Authors: Fidan Tuncer , Balcı Ali
Published: May 2016

Increasing environmental complexity and ambiguity require organizations to rely on their members' proactive behaviors to deal with potential chaotic occurences surrounding the organizational functioning. Individuals respond these occurences by displaying various proactive behavior forms to build predictability islands in ocean of uncertainty. In this context, principal proactivity is one of key determinants of effectiveness of schools functioning in complex and anarchic environments. In this study, numerous forms of proactive behaviour were categorized under six general dimensions as innovativeness, issue selling, social networking, strategic scanning, strategic learning and feedback seeking. A causal comparative design was used to determine levels of general forms of proactive behavior performed by school principals. The data were collected from school principals working at different levels of public and private schools in Istanbul Province during 2014-2015 year. According to the results of study, the most frequent form of proactive behaviour displayed by school principals was strategic learning.
Principals' Views on Stigma Tendency
Authors: Güngör Halime
Published: May 2016

Stigma takes place as a concept in the literature that affects individuals' lives negatively as well as can disrupt chemistry of organization and inhibit organizational behavior. Stigma is a concept that ostracizing individuals or groups because of their features that are not accepted by society and restricted their life on all areas. Studies on stigma have been increased during twenty years. Although school principals play the lock role and the most affecting actor in positively or negatively to school, studies on principals' stigma tendency are extremely limited. Stigma tendencies of principals' can affect chemistry of organization much more than stigma tendencies of teachers. The purpose of the study is to determine stigma tendencies of principals' by using quantitative research methods. According to research results; principals' stigma tendencies are significantly different according to seniority, level of religious feelings and health status.
Towards Self Energy-Management and Sustainable Citizens' Engagement in Local Energy Efficiency Agenda
Authors: Scorza Francesco
Published: May 2016

EU 2020 targets and global challenges concerning energy efficiency in public and private sectors generated a great number of local and sectorial approaches mainly oriented to investment promotion in energy technologies including buildings renovations. RES diffusion also generated impacts on rural and natural areas, but a comprehensive balance of recent trends still remarks only a partial success. The research hypothesis regards short-term benefits that an inclusive approach in energy management could bring in connection with energy efficiency investments at municipal scale. In fact a lot of energy wastage is linked to ineffective usage model, even in renewed buildings too. If one includes community involvement process oriented to deliver sustainable energy behaviors, one can expect a general improvement of energy saving in public and private sector. In order to be included, citizens need information: the Real time ICT application for energy monitoring represents an advancement proposed in this research. The long term perspective fits with the attitude of informed citizen to deliver self-energy management practice in everyday life. The benefits of the proposed approach regard territorial policies in the framework of EU-2020 strategy, Covenant of Mayors and UN 2030-Agenda.
Satellite Parametric Description to Ontology Concepts and Semantic Classification of Satellite Data
Authors: Abburu Sunitha , Dube Nitant
Published: May 2016

Current satellite data retrieval systems retrieves data using latitude, longitude, date, time and sensor parameters like wind, cloud etc. To achieve concept based satellite data retrieval like Storm, Hurricane, Overcast and Frost etc., requires ontological concept descriptions using satellite observation parameters and concept based classification of satellite data. The current research work has designed and implemented a two phase methodology to achieve this. The phase 1 defines ontology concepts through satellite observation parameters and phase 2 describes ontology concept based satellite data classification. The efficiency of the methodology is been tested by taking the Kalpana satellite data from MOSDAC and weather ontology. This achieves concept based retrieval of satellite data, application interoperability and strengthen the ontologies. The current methodology is implemented and results in concept based satellite data classification, storage and retrieval.
Titanium Implants Used in Traumatology Failed Sometime in Clinical Practice: Case Study
Authors: Niculescu Marius , Ghiban Brandusa , Ghiban Alexandru , Dan Gheorghe
Published: May 2016

Tibial fractures were, still are and will be a challenge for the orthopedic surgeon. In this paper we conducted a case study on a system plate-screw made by titanium that was used in clinical practice for reduction and fixation of a tibial pilon fracture. After eight months the patient returns for the ablation of metallic implants. Clinical and strengthen the fracture callus is found radiologic hypertrophic and degradation plaque.On retrieved plate were made following investigations in order to establish the causes that lead to the failure: determining the chemical composition through spectral analysis, macrostructural analysis using stereomicroscopy, microstructure analysis using optical microscope metallographic, and fractographic analysis using scanning electron microscopy. Complex analysis of the fracture surfaces of the locking plate has led to the ultimate conclusion that the material has been made self-locking plate is inadequate chemical purity satisfactory embedding, which has led to breakage within an area of ​​non-homogeneous structure. Breaking looks fragile behaviour by transgranular cleavage with sharp facets. There were also highlighted intergranular cracks between planes of cleavage sides.
Impact of Electromagnetic Radiation on the Human Organism
Authors: Sachelarie Liliana , Vasiliu Mihaela Păpușa , Farcas Dorina Maria , Daraba Oana Maria , Romila Laura
Published: May 2016

Interaction mechanisms and biological effects that different types of radiation could exert upon humans have been studied by many authors. Different studies investigated the reactions of various types of electrical equipment, power lines, mobile phones and other upon humans, their influence on the brain functions, public health or if magnetic fields (MFs) can be used for pain relief. Some authors found out that electromagnetic fields (EMFs) might be a factor which determined a number of chronic illnesses (cancer, heart diseases and sleep disorders) even to low intensity. But on the other side, because the EMFs are part of nature, being radiated by human body and its organs, the quality and intensity of the energy can either support or destroy health. Magnetic fields and electromagnetic fields are useful modalities to treat various pathologies and diseases. A number of clinical studies, in vivo animal experiments and in vitro cellular and membrane researches, suggested that EMFs and MFs stimulation reduce pain and accelerate the healing process. However, EMFs are still not widely used in clinical medicine. It is accepted that pain control occurs via a series of integrated stages, each with particular objectives essential to the tissue/system repairing processes. Electric and magnetic stimulation have been proven to provide beneficial and reproducible healing effects even when other methods have failed. As for the MFs, this is an excellent possibility as a non – invasive method to control and treat pain. Magnetic stimulation of a patient is different from drug treatment. As technology proliferates and people use more and more electronic devices, some researchers suspect EMFs contribute to a subtle assault upon people’s immune system and health. This paper aims to review the way that electromagnetic fields and other types of radiations interaction at molecular level with human organism.
Comparative Study of Different Materials for Occlusal Matrix Technique in Posterior Teeth
Authors: Monea Adriana Maria , Csinszka K. Ivacson A. , Csilla Bukhari , Bereșescu Gabriela
Published: May 2016

Posterior composite restorations are difficult to contour and polish due to their occlusal anatomy and opposing occlusion. Our study describes a technique for duplicating occlusal surface anatomy, using different dental materials that are able to copy anatomic details. The aim of the study was to evaluate the efficiency of occlusal matrix technique, by comparing technical ease of different dental materials. The study was conducted on extracted teeth which had intact occlusal surfaces or initial carious lesions at this level. An impression of the occlusal surface was made prior to cavity preparation, with four different dental materials: a flow composite, a dual-cure resin cement, a temporary acrylic resin (powder and liquid) and a temporary crown and bridge two-component material in a Unidose®. When the last layer of composite has been placed, the occlusal matrix was forced into the uncured composite to replicate the original occlusal surface, instead of performing manual curing and shaping as in the standard approach. Time needed for complete finishing the case, the hardness of each occlusal matrix and the final morphology obtained were evaluated. The main benefits of the occlusal matrix technique are the technical ease of use due to its simplicity and its high accuracy in reconstructing occlusal morphology. Although the shortest time needed for occlusal matrix preparation was for the dual-cure resin cement, the best oclusssal matrix was obtained with the temporary acrylic resin (powder and liquid).
In Vitro Chewing Simulation Model Influence on the Adhesive-Tooth Structure Interface
Authors: Caracostea Objelean Adriana , Labunet Anca , Silaghi-Dumitrescu Laura , Moldovan Marioara , Sava Sorina , Badea Mindra Eugenia
Published: May 2016

Loss of hard dental tissues of the posterior teeth during caries removal represents an important issue for conservative dentistry. The use of direct dental biomaterials in this case have to satisfy the requirements of the restored area. The studies have shown higher values of chewing forces at the molar teeth level (20-120N) compared to other teeth [1,2]. Thus, for a long-term clinical success the dental biomaterials have to assure a good marginal sealing and a high resistance to thermal and mechanical stresses developed in the lateral zones of the oral cavity [3]. The aim of this study was carried out to assess the effect of an in vitro chewing simulation model on the adhesively-bonded resin composite restorations. Standardized extended proximal cavities were prepared and restored in forty five sound human third molars. Three in vitro aging methods: a chewing simulation model (mechanical cycling and periodontal ligament simulation) (MC+PDL), thermocycling (TC) and distilled water storage (WS), were used to test the marginal sealing behavior of two adhesive techniques (an adhesive-free flowable resin composite and a self-etch all-in-one adhesive system). A weight-controlled dual-axis chewing device (CS-4.2, SD Mechatronik, Germany) was used for mechanical testing (MC) of the samples. Significantly higher marginal leakage values were observed for the chewing simulation model (MC) compared to TC and WS groups (p<0.05). No statistical correlations were found with regard to aging methods for the tracer’s infiltration of the two adhesive techniques. The dual-axis chewing simulator (CS-4.2) due to its facile mechanical adjustment system may be used for different other in vitro aging models or simulated clinical settings.
Application of Fluorine Containing Bioactive Glass Nanoparticles in Dentin Hypersensitivity Treatment
Authors: Camargos Lins Carolina Emmanuelle , de Carvalho Sandhra Maria , de Oliveira Agda Aline Rocha , de Magalhães Pereira Marivalda
Published: May 2016

The effect of Bioactive Glass on remineralization of dentin is the focus of the present study due to its excellent regenerative properties in mineralized tissues. It is known that the effect of Bioactive Glass can be enhanced at the nanoscale. In addition, the incorporation of Fluorine in the glass structure makes possible the formation of Fluorapatite (FAP). The aim of this study was to synthesize and characterize a new system of Fluorine containing Bioactive Glass Nanoparticles (FBGNP), and evaluate the potential for in vitro dentin remineralization by occlusion of dentinal tubules. The FBGNPs produced were uniform, with spherical shape and nanoscale size. Agglomeration or partial sinterization of the particulate system probably occurred after heat treatment. The results suggest the formation of FAP crystals embedded within the matrix of the Bioactive Glass. The gel containing FBGNP produced was effective in obliterating the dentinal tubules in vitro, showing that FBGNP is a potential material to be used for treatment of dentin hypersensitivity.
Magnetite/Hydroxyapatite Composite Particles-Assisted Pore Alignment of Tilapia Fish Scale Collagen-Based Scaffold
Authors: Irawan Vincent , Sugiyama Tomomei , Ikoma Toshiyuki
Published: May 2016

Pore alignment is a vital step to obtain bone-mimicking microstructure in collagen-based scaffold. The porous structure can be controlled by altering the configuration of ice crystals formed in collagen solution. In this study, movements of magnetite/hydroxyapatite composite particles were used to alter the configuration of pore alignment formed in 1.0 and 1.5wt% collagen solutions (HCol 1.0 and HCol 1.5 respectively) by applying moving external magnetic field. In case of HCol 1.0 pores were aligned parallel to the magnetic field, while for HCol 1.5 pores were aligned at curve shape. Different results of pore alignment were thought to originate from differences in collagen fiber alignment caused by magnetic particles movement paths. This result thus opens up the possibility of controlling pore alignment by utilizing magnetic particle movement.
Development of Bioactive PEEK by the Function of Apatite Nuclei
Authors: Fukushima Keito , Yabutsuka Takeshi , Takai Shigeomi , Yao Takeshi
Published: May 2016

Micropores were formed on the surface of a polyetheretherketone (PEEK) by soaking in sulfuric acid. In order to provide bioactivity to PEEK, the surfaces of the specimens were treated with glow-discharge in O2 atmosphere and Apatite Nucleus (AN) was precipitated in the pores. The bioactivity of the specimens was evaluated by using SBF and adhesive strength of formed apatite layer was measured.
Human Mesenchymal Stem Cells Behavior on Synthetic Coral Scaffold
Authors: Mahanani Erlina Sih , Bachtiar Indra , Ana Ika Dewi
Published: May 2016

For bone tissue engineering, corals have long history to be used as scaffold to promote bone regeneration. However the use of a lot of corals may damage their habitates. For this reason, a strategy to mimic coral in a synthetic form is needed. As an ideal scaffold, synthetic coral must provide structure and initial support for cell attachment and proliferation. The aim of this study was to investigate the attachment and proliferation of human Mesenchymal Stem Cells (h-MSC) on synthetic coral scaffold, to provide information on the behavior of h-MSC on the designated scaffold. Synthetic coral scaffolds were prepared from bovine gelatine and CaCO3 with 5:5 in 10% w/v concentration in aquadest. Sodium citrate was used as dispersant in the suspension. Gelatin-CaCO3 suspension was moulded in a plastic cover of 24 well plate, then freezed at -20°C for 24 hours, freeze dried for 24 hours and continued by dehydrothermal crosslinking for 72 hours. After the fabrication, synthetic coral scaffolds were subjects to cover the bottom of the well for cell culture. Human Mesenchymal Stem Cells (h-MSC) were seeded and divided into 2 groups, control group without scaffold and the one with scaffold. All groups were incubated for 3, 6, and 24 hours. Cells attatchment were determined by deduction of the cells unattached from total cells seeding. Proliferation of h-MSC were done in 3 groups ie., control group without scaffold, scaffold only and scaffold incorporated Platelet Rich Plasma (PRP) in the bottom of well. All groups were incubated for 24, 48 and 72 hours. Human Mesenchymal Stem Cells attached faster to synthetic coral scaffold than the control. Its proliferation behavior was faster in the scaffold incorporated PRP, showing better interaction of scaffold and cells with the incorporation of morphogenetic factor.
In Vivo Evaluation of Zinc-Containing Nanostructured Carbonated Hydroxyapatite
Authors: Ribeiro Simone , Sartoretto Suelen Cristina , Resende Rodrigo , Uzeda Marcelo , Alves Adriana Terezinha , Santos Silvia Albuquerque , Pesce Giovana , Rossi Alexandre Malta , Granjeiro J.M. , Miguel Fulvio , Calasans-Maia Mônica Diuana
Published: May 2016

The hydroxyapatite (HA) is a biocompatible and bioactive biomaterial used as bone substitute, however, the high crystallinity of HA and consequently its low solubility may be a limitation for its clinical use. In order to improve the biosorption of HA, the partial substitutions in the chemical structure and doping with small amounts of impurities have been study. The objective of this study was to evaluate the biocompatibility of 3% Zinc-containing nanostructured carbonated hydroxyapatite (ZncHA) compared with the carbonated hydroxyapatite (cHA), both synthesized at 37°C and non-sintered, using as control the stoichiometric HA microspheres in subcutaneous of mice. The X-ray Diffraction (XRD) and Vibrational Spectroscopy in Infra Red Fourier Transform (FTIR) were used to characterize the biomaterials. In vivo test was performed in BALB/c mice by implanting of HA, cHA and ZncHA spheres in the subcutaneous tissue for 1, and 9 weeks (n=5). The negative control consisted in incision without material implantation (Sham group). The samples were histological processed to descriptive analysis of biological effect. The microscopic analysis showed a similar granulation reaction between groups at the first experimental period. In 9 weeks there was a time dependent biosorption of cHA compared with other groups. In conclusion, the biomaterials tested were biocompatible and cHA group showed a significant biosorption in comparison with HA and ZncHA groups. The doping of zinc did not influence the biocompatibility of biomaterial, however, change the biosorption response
Preparation of Carbonated Apatite Membrane as Metronidazole Delivery System for Periodontal Application
Authors: Ardhani Retno , Setyaningsih Setyaningsih , Hafiyyah Osa Amila , Ana Ika Dewi
Published: May 2016

Introduction. Long term infection on periodontal tissue, mainly caused by anaerobic microbial, is not only related with tooth loss which lead to functional and esthetical impairment but also with increasing infection risk on other vital organs such as heart. Metronidazole is drug of choice for anaerobic bacterial infection. In this research, Metronidazole delivery system from carbonated apatite-based material was designed to increase the antibiotic therapeutic potential on local application as well as to promote tooth-supporting bone healing as a thin membrane to be applied on narrow periodontal tissue.Experimental. Metronidazole delivery system was prepared using different carbonate apatite composition on gelatin hydrogel system which was freeze-dried then polymerized by thermal treatment. Total 6 gelatin-carbonated apatite compositions were prepared: 10:0, 9:1, 8:2, 7:3, 6:4 and 5:5.The membranes were characterized by Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Water-content, air-water contact angle, tensile strength, Metronidazole-loading capacity, degradation profile and Metronidazole-release profile were studied to describe each composition potential as Metronidazole delivery system.Results and Discussion. Study on FTIR spectra and XRD confirmed preparation methods as standard procedures to prepare membrane formed delivery system-containing carbonate apatite. Descriptively from SEM, the film surface porosity was elevated by the increase of carbonate apatite composition. Tensile strength decreased was found by the increase of carbonate apatite composition. Water content, air-water contact angle, Metronidazole-loading capacity was not different significantly (P>0.05). Profile of degradation and Metronidazole-release from the membranes was different between compositions.Conclusions. This study results were essential to support next research on antibiotic potential using different anaerobic bacteria culture as well as bone regeneration potential on periodontal infection in vivo.
Hydroxyapatite/PLA Biocomposite Thin Films for Slow Drug Delivery of Antibiotics for the Treatment of Bone and Implant-Related Infections
Authors: Macha Innocent J. , Ben-Nissan Besim , Santos Jerran , Cazalbou Sophie , Milthorpe Bruce
Published: May 2016

Drug delivery systems were developed from coralline hydroxyapatite (HAp) and biodegradable polylactic acid (PLA). Gentamicin (GM) was loaded in either directly to PLA (PLAGM) or in HAp microspheres. Drug loaded HAp was used to make thin film composites (PLAHApGM). Dissolution studies were carried out in phosphate buffered saline (PBS. The release profiles suggested that HAp particles improved drug stabilization and availability as well control the release rate. The release also displays a steady state release. In vitro studies in human Adipose Derived Stem Cells (hADSCs) showed substantial quantities of cells adhering to hydroxyapatite containing composites. The results suggested that the systems could be tailored to release different clinical active substances for a wide range of biomedical applications.
Analysis on the Setting of Brushite Bone Cement after Storage in the Humid Environment
Authors: Chung Tai Joo , Oh Kyung Sik
Published: May 2016

The cause of the degradation was analyzed by applying the highly humid conditions during the storage of cement composed of β-tricalcium phosphate (β-TCP) and monocalcium phosphate monohydrate (MCPM). For the β-TCP and MCPM stored separately under the humid environment, the mild increase in the setting time was observed, and the product after the setting was entirely dicalcium phosphate dihydrate (CaHPO42H2O: DCPD). However, for the β-TCP and MCPM stored mixed under the same condition, the setting time significantly increased with the period of storage, and the product contained dicalcium phosphate (CaHPO4: DCP) as major phase, resulting in the loss of setting ability. The formation of DCP could be because of the weak driving force for setting, caused by a feeble supply of water from moisture. As the formation of DCPD requires stronger driving force to overcome the activation barrier, sufficient amount of water is essential. Humid environment during the storage decreased the driving force by the formation of DCP, and the driving force to produce DCPD was lost during the actual setting.
Fabrication of Bone-Like Apatite-Phosphatidylcholine Composite Thin Film by Biomimetic Method
Authors: Mizutani Hiroto , Yabutsuka Takeshi , Takai Shigeomi , Yao Takeshi
Published: May 2016

When the pH or the temperature of a simulated body fluid (SBF) is raised, fine particles of calcium phosphate are precipitated. We found that this particle actively induces apatite formation in body fluid or SBF and named it Apatite Nucleus (AN). In this study, we fabricated bone-like apatite self-supporting thin film by biomimetic method using AN. We analyzed it by FE-SEM, EDX, TF-XRD and ICP. It was found that the film has similar crystallinity and Ca/P ratio to those of biological apatite and ca. 10 μm of thickness.
Can European Sea Bass (Dicentrarchus labrax) Scale Be a Good Candidate for Nano-Bioceramics Production?
Authors: Sahin Yesim Muge , Gunduz Oguzhan , Ficai Anton , Ekren Nazmi , Tuna Ali , Inan Ahmet Talat , Oktar Faik Nuzhet
Published: May 2016

Bioceramics are commonly used biomaterials for orthopedic and dental applications. Among these bioceramics, hydroxyapatite (HA) and tricalcium phosphate (TCP) are of interest and are used in various biomedical applications. Production of bioceramics from natural materials such as bovine and sheep bones with calcination method, is possible. Lately, fish scales become an alternative biological source for bioceramic production. The present study proposes an approach to obtain HA bone-scaffolds from European Sea Bass (Dicentrarchus labrax) scales aiming to provide nano-biomaterials via calcination method. Untreated fish scales are obtained and are carefully cleaned from their meat and grease. They are washed with alkaline water several times and calcinated at 850°C for 4 hours. Energy Dispersive Spectroscopy (EDS), X-ray diffraction analysis, Scanning Electron Microscopy (SEM) studies are performed. Various calcium phosphate species (HA, TCP) are identified in the study. SEM images prove the presence of the nano-scale structures. This study indicates calcination as a simple way of nano-scale bioceramic production for drug delivery and tissue engineering applications. Being produced from wastes of a sustainable and cheap source, these bioceramics can be good candidates for future clinical applications.
Polymethylmethacrylate Composite Bone Cement Adding with Tetracalcium Phosphate
Authors: Chung Ren Jei , Ou Keng Liang , Liang Han Wen
Published: May 2016

Polymethylmethacrylate (PMMA) cement has been used in orthopedics for more than 70 years. The advantages of PMMA bone cement include high compressive strength, stickiness, deformable ability and rapid self-setting. But the heat produced during polymerization would hinder the recovery. In order to improve the properties, in this research we added tetracalcium phosphate (TTCP) into polymethylmethacrylate cement as TP cement. A serious of characterizations including thermal property study, compression strength and micor-CT evaluation were carried out. According to the results, the polymerization heat was significantly reduced for the TP cement. The compressive strength was also enhanced with TTCP addition. TP-10 had better properties. As to thermal tests, TP-40 showed better results. Micro CT was used to monitor the composition inside the materials, and the results showed that TTCP was well dispersed in the PMMA matrix. The composite PMMA bone cement adding with tetracalcium phosphate seemed to be a potential candidate as low temperature product.
Transformation of Apatite Cement to B-Type Carbonate Apatite Using Different Atmosphere
Authors: Cahyanto Arief , Tsuru Kanji , Ishikawa Kunio
Published: May 2016

Apatite cement (AC) is a breakthrough in biomaterials for the reconstruction of the bone defect. However, the replacement of AC to bone up to the present time is still controversial for researchers. Several researchers have reported that AC was replaced by bone while others claimed replacement was limited. The aim of this study is to investigate the transformation mechanism of AC to B-type carbonate apatite (CO3Ap) using different atmosphere. An in vitro study mimicking the body environment was employed in order to examine the effect of setting atmosphere on the composition of set AC. An equimolar of tetracalcium phosphate (TTCP; Ca4(PO4)2O) and dicalcium phosphate anhydrous (DCPA; CaHPO4) mixed with distilled water was enabled to harden at 37°C and 100% of relative humidity under presence of 5% CO2, 100% CO2, and 100% N2 atmospheres. XRD and FT-IR analyses revealed that in the presence of 100% CO2 and 5% CO2, B-type CO3Ap could be determined and only small amounts of TTCP remained unreacted. On the contrary, in the presence of 100% N2, the CO32- bands could not be detected and larger amount of TTCP remained unreacted compared to 5% CO2and 100% CO2 atmospheres. SEM morphology showed that the microstructure of AC was entangled and locked to each other. In addition, the small needle like crystals appeared in the surface of 100% N2, similar to hydroxyapatite. We concluded that the CO32- ions incorporated in AC during setting reaction may be one of the essential factors for CO3Ap formation.
DNA Detection Using SiC Nanowire Based Transistor
Authors: Bano Edwige , Fradetal Louis , Stambouli Valerie , Attolini Giovanni
Published: May 2016

The fast and direct detection of small quantities of biomolecules improves early medical diagnosis of certain serious diseases as cancers and can be used to detect in situ the presence of pathogenic viruses or GMOs for food industry, protection environmental and bio-defense. Numerous research projects are conducted on nanoelectronic devices that can perform such detection with high sensitivity using nanostructures. Currently, these devices are made from Silicon nanowires [1]. For these applications, Silicon Carbide (SiC) material can advantageously replace Silicon as this semiconductor is now known to be biocompatible and to show a high chemical inertness [2]. Here, we present the electrical detection of DNA using a SiC Nanowire Field Effect Transistor (NWFET). The NWFETs are fabricated and then functionalized with DNA molecules. Between each step of the functionalization process, I-V characteristic measurements are performed. Comparative and simultaneous measurements are carried out on two SiC NWFETs: one is the sensor and the second one is used as a reference. Some interesting properties of the sensor are studied for the first time which opens the way to future developments of SiC nanowire based sensors.
Sublimation Growth of 4 and 6 Inch 4H-SiC Low Defect Bulk Crystals in Ta (TaC) Crucibles
Authors: Makarov Yuri , Litvin D. , Vasiliev A. , Nagalyuk S.
Published: May 2016

Recently, the wide bandgap semiconductors, especially silicon carbide (SiC), have become more important due to the unique electrical and thermophysical properties that make them applicable to a variety of electronic devices (Schottky and PiN diodes, JFETs, MOSFETs, etc.). For these applications, the crystals need to be manufactured with highest possible quality, both structural and chemical, at reduced cost. This requirement places rather extreme constraints on the crystal growth as the simultaneous goals of high quality and low cost are generally incompatible.Refractory metal carbide technology, particularly, tantalum carbide (TaC), was originally developed for application in highly corrosive and reactive environments. Yu. Vodakov [1] demonstrated for the first time advantages of use of refractory metal carbides for PVT growth of SiC and later AlN bulk crystals. In the present paper we discuss the effect of refractory metal on PVT growth of large diameter 4H SiC bulk crystals.
Ni2Si/4H-SiC Schottky Photodiodes for Ultraviolet Light Detection
Authors: Mazzillo Massimo , Sciuto Antonella , Roccaforte Fabrizio , Bongiorno Corrado , Modica Roberto , Marchese Salvatore , Badalà Paolo , Calì Denise , Patanè Francesco , Carbone Beatrice , Russo Alfio , Coffa Salvo
Published: May 2016

Ultraviolet (UV) monitoring is of great interest in the healthcare field to prevent excessive UV exposure risks. In the last years silicon carbide (SiC) has emerged as a suitable material for the fabrication of UV detectors. In this paper we propose a 4H-SiC Schottky photodiode with a continuous very thin Ni2Si layer operating at 0V, properly designed for UV radiation monitoring.
Structural Optimization of 4H-SiC BJT for Ultraviolet Detection with High Optical Gain
Authors: Bai Yun , Li Chengzhan , Shen Hua Jun , Tang Yi Dan , Liu Xin Yu
Published: May 2016

The 4H-SiC n-p-n BJT for ultraviolet detection with high optical gain is proposed and optimized in this paper. The effect of structural parameters of 4H-SiC phototransistor on the performance of the detectors is simulated and the effect mechanism is analyzed. The simulation results show that the 4H-SiC phototransistors detect UV light with a response wavelength below 380 nm. It is suggested that the base parameters are important to the responsivity of the 4H-SiC BJT. With optimized parameters the 4H-SiC UV phototransistor exhibits peak responsivity as high as 4617 A/W corresponding to a quantum gain of 2.2×105 under the bias voltage of 5 V.
Development of a PSpice Model for SiC MOSFET Power Modules
Authors: Johannesson Daniel , Nawaz Muhammad
Published: May 2016

In this paper, the static and dynamic characteristics of a 1200 V and 120 A silicon carbide (SiC) MOSFET power module has been measured, simulated and verified in the PSpice circuit simulation platform. Experimental measurements and PSpice simulations are performed to extract the technology dependent modeling parameters. The model is implemented in the PSpice circuit simulation platform using both standard components and analog behavior modeling (ABM) blocks. The simulation results of the model is fairly accurate and correlates well with the measured results over a wide temperature range. The developed model is used to facilitate converter design at cell level and hence predict and optimize the cell performance (i.e., energy losses) with varying circuit parameters (e.g., stray inductances, temperatures, gate resistances etc.,).
High-Temperature Transient Thermal Analysis for SiC Power Modules
Authors: Kato Fumiki , Nakagawa Hiroshi , Yamaguchi Hiroshi , Sato Hiroshi
Published: May 2016

Transient thermal analysis is a very useful tool for thermal evaluation to realize the stable operation of SiC power modules which are operated at higher temperatures than conventional Si power modules. A transient thermal analysis system to investigate the thermal characteristics of SiC power modules at high temperature is presented. We have found that precise temperature measurement at the initial stage of the junction temperature decay curve is necessary in order to evaluate the thermal resistance and heat capacity of the die attach, since the thermal diffusivity of SiC is larger than that of Si and the temperature distribution of SiC die was considered. Using the proposed transient thermal analysis method, the thermal resistance and heat capacity of the AuGe die attach under the SiC-SBD was successfully evaluated at temperatures up to 250 °C.
Newly Developed Switching Analysis Method for 3.3 kV 400 a Full SiC Module
Authors: Hatsukawa Satoshi , Toyoshima Shigenori , Tsuno Takashi , Mikamura Yasuki
Published: May 2016

We have demonstrated a new analysis method using a precise equivalent circuit of 3.3 kV 400 A full SiC modules and showed that the calculated waveforms well agree with the measured waveforms. We have also examined the current distribution in the module by utilizing this equivalent circuit model.
Evidence of Processing Non-Idealities in 4H-SiC Integrated Circuits Fabricated with Two Levels of Metal Interconnect
Authors: Spry David J. , Neudeck Philip G. , Chen Liang Yu , Evans Laura J. , Lukco Dorothy , Chang Carl W. , Beheim Glenn M.
Published: May 2016

The fabrication and prolonged 500 °C electrical testing of 4H-SiC junction field effect transistor (JFET) integrated circuits (ICs) with two levels of metal interconnect is reported in another submission to this conference proceedings. While some circuits functioned more than 3000 hours at 500 °C, the majority of packaged ICs from this wafer electrically failed after less than 200 hours of operation in the same test conditions. This work examines the root physical degradation and failure mechanisms believed responsible for observed large discrepancies in 500 °C operating time. Evidence is presented for four distinct issues that significantly impacted 500 °C IC operational yield and lifetime for this wafer.
Atomistic Simulations and Interfacial Morphology of Graphene Grown on SiC(0001) and SiC(000-1) Substrates
Authors: La Magna Antonino , Deretzis Ioannis , Giannazzo Filippo , Nicotra Giuseppe , Roccaforte Fabrizio , Spinella Corrado , Yakimova Rositza
Published: May 2016

A Kinetic Monte Carlo scheme is applied to simulate with atomic resolution the synthesis of mono (few) layer(s) graphene (Gr) from a silicon carbide (SiC) substrate by selective evaporation of silicon (Si) atoms. The simulation computes the individual dynamics of the residual carbon (C) atoms which diffuse and reconfigure starting from the positions occupied in the SiC hexagonal lattice to the final Gr honeycomb structure. During the transition they gradually modify hybridization (from sp3 to sp2) and bond partners (from Si-C to C-C). We demonstrate that our method is able to recover the complex evolution steps of the epitaxial Gr on SiC in large systems for large time intervals. Moreover, the simulation results can be validated directly by means of comparison with experimental data when varying the material (e.g. initial surface configuration or polarity) or process (e.g. temperature and pressure) conditions.
Hot Electron Transistors Based on Graphene/AlGaN/GaN Vertical Heterostructures
Authors: Fisichella Gabriele , Greco Giuseppe , Di Franco Salvatore , Lo Nigro Raffaella , Schilirò Emanuela , Roccaforte Fabrizio , Giannazzo Filippo
Published: May 2016

This paper presents a study of the vertical current transport in a graphene (Gr) heterostructure with AlxGa1-xN/GaN, which represent the main building block of a novel high frequency device, the hot electron transistor (HET) with Gr base. The morphological and electrical properties of this heterostructures have been investigated at nanoscale by atomic force microscopy (AFM) and conductive atomic force microscopy (CAFM). In particular, local current-voltage measurements by the CAFM probe revealed the formation of a Schottky contact with low barrier height (∼0.41 eV) and excellent lateral uniformity between Gr and AlGaN. Basing on the electrical parameters extracted from this characterization, the theoretical performances of a HET formed by a metal/Al2O3/Gr/AlGaN/GaN stack have been evaluated.
Amplification in Graphene Nanoribbon Junctions
Authors: Pezoldt Joerg , Hähnlein Bernd , Jacobs Heiko O. , Schwierz Frank
Published: May 2016

All carbon three terminal junctions were fabricated from epitaxial graphene grown on semiinsulating Si-face 4H-SiC. It is demonstrated that self-contained gate devices exhibit current modulation characteristics. The obtained current gain depends on the device design and is controlled by the applied gate voltage.
Highly Sensitive NO2 Graphene Sensor Made on SiC Grown in Ta Crucible
Authors: Novikov S. , Makarov Yuri , Helava Heikki , Lebedev S. , Lebedev Andrey , Davydov Valeri
Published: May 2016

Graphene films were grown on SiC substrates by annealing in vacuum or in Ar flow. Gas sensors based on graphene films were made and tested on response to nitrogen dioxide. Graphene film is used in the sensor. The graphene film grown by annealing in Ar flow shows superior sensitivity compared to that annealed in vacuum. Both sensors exhibit good potential for environmental research and monitoring
Abnormal Raman Spectral Variation with Excitation Wavelength in Boron-Doped Single-Crystalline Diamond
Authors: Yoshikawa Masanobu
Published: May 2016

The Raman spectra of boron-doped single-crystalline diamond were measured at excitation wavelengths between 364.0 and 1064.0 nm and found that the first-order Raman band at 1332 cm-1 shifts to the low-frequency side, broadens, and develops a derivative-like lineshape as the boron concentration increases. The derivative-like lineshape can be explained by Fano interference. Furthermore, I found that the asymmetric lineshape changes between excitation wavelengths of 514.5 and 785.0 nm. From a comparison of the normalized relative Raman intensity as a function of the excitation energy and the density of states (DOS) in the valence band in the B-doped diamond calculated previously by the coherent potential approximation, the abnormal change in the Raman lineshape is attributed to a change in the DOS in the valence band at approximately 2.0 eV. Raman spectroscopy provides us with extensive information on carrier concentrations, and electronic band structures of B-doped diamond.
Development of GaN-Based Gate-Injection Transistors and its Power Switching Application
Authors: Morita Tatsuo , Ueda Tetsuzo
Published: May 2016

This paper reviews the state-of-the-art technologies of the normally-off GaN Gate Injection Transistor (GIT) and its applications such as inverter for motor drive and Power Factor Collection (PFC). Fundamental performances such as the current-collapse-free operation and the excellent switching performance are reviewed.
15 eV Protons Irradiation of the GaN Schottky Diodes
Authors: Lebedev Alexander A. , Belov S.V. , Mynbaeva Marina G. , Strel'chuk Anatoly M. , Bogdanova Elena V. , Makarov Yuri , Usikov A.S. , Kurin Sergey , Barash I.S. , Roenkov Alexander D. , Kozlovski Vitalii V.
Published: May 2016

Schottky-barrier diodes with a diameter of ~10 μm are fabricated on n-GaN epitaxial films grown by hydride vapor-phase epitaxy (HVPE) on sapphire substrates. The changes in the parameters of the diodes under irradiation with 15 MeV protons are studied. The carrier rate was found to be 130-145 cm-1. The linear nature of the dependence N = F (D) (N is carrier concentration, and D, the irradiation dose) shows that compensation of the material is associated with transition of electrons from shallow donors to deep acceptor levels which are related to primary radiation defects.
AlGaN/SiC Heterojunction Ultraviolet Photodiodes
Authors: Sampath Anand V. , Chen Yoajia , Zhou Q. , Enck Ryan W. , Garrett Gregory A. , Vanmil Brenda L. , Chung Roy B. , Reed Meredith L. , Shen H. , Campbell Joe C. , Wraback Michael
Published: May 2016

We report on improvement in the deep ultraviolet (DUV) photoresponse of SiC based detectors through the development of n- AlxGa1-xN / i-p SiC heterojunction photodiodes. Fabricated photodiodes have high external quantum efficiency (EQE), greater than 60%, over a wide spectral range from 215-255 nm that is ~10x enhancement in performance over comparable homogenous SiC photodiodes at the shortest wavelength. This is attributed to photogeneration of carriers within the SiC depletion region by DUV illumination of the diode through the n- AlxGa1-xN “window”, as compared to a typical homogenous SiC n-i-p structure where the carriers are photogenerated in the n-type neutral region, resulting in more efficient collection of holes through drift
Long Charge Carrier Lifetime in As-Grown 4H-SiC Epilayer
Authors: Karhu Robin , Booker Ian , Ivanov Ivan G. , Janzén Erik , Hassan Jawad
Published: May 2016

Over 150 μm thick epilayers of 4H-SiC with long carrier lifetime have been grown with a chlorinated growth process. The carrier lifetime have been determined by time resolved photoluminescence (TRPL), the lifetime varies a lot between different areas of the sample. This study investigates the origins of lifetime variations in different regions using deep level transient spectroscopy (DLTS), low temperature photoluminescence (LTPL) and a combination of KOH etching and optical microscopy. From optical microscope images it is shown that the area with the shortest carrier lifetime corresponds to an area with high density of structural defects.
Improvement of 4H-SiC Epitaxial Layers Grown on 2o Offcut Si-Face Substrates
Authors: Asamizu Hirokuni , Yamada Keiichi , Tamura Kentaro , Kudou Chiaki , Nishio Johji , Masumoto Keiko , Kojima Kazutoshi
Published: May 2016

The surface quality of epitaxial layers grown on 2° offcut substrates was improved. These substrates require a lower growth temperature and a lower C/Si ratio than their 4° offcut counterparts to suppress macro step bunching. Surface morphology, triangular defect density, and doping uniformity presented a trade-off relationship with respect to growth parameters. The implementation of a low C/Si ratio buffer layer led to a balance between surface defect density, which reached a minimum of 0.2 cm−2, and good doping uniformity on an equivalent wafer size (150 mm). An evaluation of metal–oxide–semiconductor capacitors and Schottky barrier diodes fabricated on 2° offcut epitaxial layers showed that the quality of these epitaxial layers was satisfactory for application in devices.
p-Type Doping of 4H- and 3C-SiC Epitaxial Layers with Aluminum
Authors: Zielinski Marcin , Arvinte Roxana , Chassagne Thierry , Michon Adrien , Portail Marc , Kwasnicki Pawel , Konczewicz Leszek , Contreras Sylvie , Juillaguet Sandrine , Peyre Hervé
Published: May 2016

Exhaustive experimental study of aluminum incorporation in epitaxial 4H-SiC and 3C‑SiC films grown by chemical vapor deposition (CVD) was performed. The influence of polytype and substrate orientation was verified. Role of principal process conditions (growth temperature and pressure, deposition rate, chemical environment) was investigated in details. Finally, the evolution of optical properties of resulting SiC films with Al content was examined.
Structural Study of the Innovative 3C-SiC/Si/3C-SiC/Si Heterostructure for Electro-Mechanical Applications
Authors: Khazaka Rami , Portail Marc , Vennéguès Philippe , Alquier Daniel , Michaud Jean François
Published: May 2016

In this work, we report the growth of a 3C-SiC layer oriented along the [111] direction on Si (110)/3C-SiC(001)/Si (001) heterostructure. The growth of the complete layer stack occurs in one deposition run in a Chemical Vapor Deposition (CVD) reactor on on-axis Si (001) substrate. The structural properties of the 3CSiC(111) layer are discussed and the impact of the first 3C-SiC layer on the subsequent growth is highlighted. The 3C-SiC(111) top layer shows two domains rotated by 90o around the growth direction directly linked to the domains rotation in the Si epilayer underneath it. Furthermore, μtwins and stacking faults are present on the inclined (111) planes in the 3C-SiC epilayer.