bluuebunny/crossref_metadata_2025 huggingface dataset:
A Microblogging Opinion Leader Recognition Algorithm Based on MapReduce
Authors: Dong Li Li , Zhu Yu Jie , Zhang Xiang
Published: June 2014

Related researches on the influence of microblogging users are only given users’ influence ranking, while cannot determine the problem that which user plays a guiding role in the dissemination of information in the microblogging network. This paper proposed a microblogging opinion leader recognition algorithm called LeadersRank based on personalized PageRank algorithm. On the basis of LeadersRank algorithm research, since the problem of that current microblogging information has been massive data, using the idea of MapReduce programming model to improve the LeadersRank algorithm, so that designed a LeadersRank distributed parallel algorithm based on MapReduce algorithm running in the cloud platform hadoop environment. Finally, experiments verified the effectiveness of the two methods, and made analysis of experimental results.
An Algorithm Based on Optimal Routing Function in Mobile Ad Hoc Networks
Authors: Sun Wen Feng , Li Ji Zhong
Published: June 2014

Nowadays, with continuous progress in Ad hoc technology, Ad hoc network is no longer limited to some specific areas, furthermore is integrated with mobile communication to expand application scope. Three key factors affecting the quality of routing is enumerated and analyzed in detail in this paper. Among previous research on the integration of Ad hoc networks and mobile communication system, most of them are based on a single factor analysis, not comprehensive analysis. So aiming at this disadvantage, a novel concept, namely optimal routing function, is suggested on the basis of comprehensive consideration of three key factors.
An IEEE 802.11n Based Multi-Channel MAC Protocol for Underground Metal Mine Wireless Network
Authors: Jin Feng , Liu Xu , Lv Xiao , Zhang Da
Published: June 2014

At present, wireless communication networks obtain preliminary application in underground metal mines, but the problems of anti-interference ability and communication capability generally exist. With regard to this situation, this paper proposed an IEEE 802.11n based multi-channel MAC protocol (MC-MAC), which supports multi-channel dynamically switching by evaluating real time channel packet received rate. MC-MAC can improve wireless networks’ data throughput, anti-interference ability, and communication reliability. To evaluate the practical performance of MC-MAC, This paper designed and implemented an wireless access point based on IEEE 802.11n as testing platform, experimental results show that MC-MAC can provide 193Mbps physical links rate and improve network anti-interference ability effectively, it is suitable for underground metal mine applications.
An Improved Method for Maintenance Scheme of an Inter-Zone Route
Authors: Wu Jing , Meng Guang Xue , Chen Zhen Guo , Cao De Sheng
Published: June 2014

In ad hoc networks, the maintenance scheme of an inter-zone route in ZRP (Zone Routing Protocol) makes ZRP take less reliability, more transmission delay and more routing overheads. Aiming at the problem above, BSRZRP (Backup Segment Routes based Zone Routing Protocol) was proposed. In BSRZRP, an inter-zone route was repaired by using backup segment routes as much as possible when an inter-zone route-link opened. This improved method is favor to improve protocol reliability and reduce transmission delay and routing overheads of protocol.
Design and Implementation of ZigBee Gateway for Ethernet
Authors: Yan Shi Yang
Published: June 2014

WSN (Wireless sensor network) using ZigBee has aroused people’s high interest, ZigBee is considered to be a general solution in many fields such as intelligent household, industrial application, security monitoring and medical application. But wireless sensor network can only provide service within a certain range, in order to overcome this limitation and provide remote application capacity, this paper proposes a technological solutions for the interconnection of ZigBee network and the Ethernet, develops a ZigBee gateway based on ARM platform. Based on the analysis of the ZigBee protocol stack and TCP/IP protocol stack, the protocol conversion mechanism of ZigBee and TCP/IP is presented. Through transplantation LwIP protocol stack, this paper achieves the goal of connecting gateway to Internet, and finally realizes the conversion from ZigBee network to TCP/IP network.
Evaluation Method for Anti-Interference Performance of Measuring Based on Entropy Loss
Authors: Li Guo Jing , Zhang Bao Ling , Wang Xiao Yu
Published: June 2014

The concept of information entropy is applied to evaluation for anti-interference performance of velocity and distance measurement in DS/FH hybrid spread spectrum TT&C (Tracking, Telemetry & Command) system, establishing an evaluation model where the entropy loss degree is used as an index under the rule of information, and analyzing the impact on the index from the changing of interference parameters. The feasibility of using entropy loss degree as an evaluation index was verified by simulation.
Research of Mining High Power 802.11n Access Point
Authors: Lv Xiao , Zhang Da , Jin Feng , Liu Xu , Han Xi
Published: June 2014

This paper designs and implements an IEEE 802.11n based mining high power access point to improve the disadvantages of low throughput, low communication distance which are met in current mining communication systems. By adding high power design to transmitting and receiving path, this design can get over more than 190Mbps throughput in lab testing, and can achieve more than 2km outdoor communication distance. Test results show that the mining high power access point is more suitable for mining application.
Evaluation of B+-Tree and CSB+-Tree in Main Memory Database
Authors: Sun Feng Dong , Wang Lan
Published: June 2014

Index is indispensable in database system to speeding up data access. Commonly used indexes in main memory databases are B+-Tree, T-Tree and their variants. Cost model of main memory database are more complex than disk-oriental database, and relatively little work has been done on this area. This paper establishes a cost model for B+-Tree and CSB+-Tree, analyzes their main performance factors. We perform several experiment evaluations on the cost model.
Research on the Spatial Query Technology of Geospatial Database
Authors: Sun Lei Gang , Liu Jian Feng , Xu Quan Hong
Published: June 2014

The application requirement of Geospatial data is increasing and complex as it is getting numerous as a result of furthering study on geosciences. Based on a deeply research on Oracle Spatial storage management mechanism, this paper proposed a method that applies the graph theory to domain of optimizing spatial query of massive geographical data, and established a geospatial data query model in order to settle a problem of lower spatial query efficiency in geospatial database. Combining with the practical applications, this paper did a conventional spatial query test and a spatial query based on geospatial data model respectively. The result is that the spatial query based on geospatial data query model has a better efficiency than that on conventional method. Besides, this model can greatly improve the spatial query performance and this improvement will be increasingly apparent as the data volume increases.
The Research of Interactions in Date Processing and Data Mining
Authors: Zhang Min , Huang Wei Zhong , Ji Qi
Published: June 2014

With the rapid development of global information technology and the rapid popularization of the Internet and modern information system entered the era of big data, people's daily work and life are faced with too much data and information explosion, urgently need to be an effective technology to help people from these huge amounts of data excavated really need and valuable knowledge, so the study of interaction in the process of data processing, and data mining research work have the vital significance.
Application of Digital Image Processing Techniques in the Vessel Flexure System
Authors: Xue Chun Yan
Published: June 2014

For a vessel flexure of measure ship under the influence of internal and external environmental factors, which resulting data errors of measuring equipment, the development of the "Vessel Flexure System" can solve the problem. The paper briefly describes the principle and hardware components of Vessel Flexure System, focuses on the application of digital image processing techniques used on linear CCD, put forward the interpretation method of gravity-center, which can determine the location of the center of facula accurately.
Applied Study of Size Measurement Based on Image
Authors: Zhang Wei Wei , Yuan Lu Lu
Published: June 2014

Part size measurement is a very common and important projects in the production and life, Image size measurement system is composed of camera and Image processing algorithms, Size measurements is finished on this platform. Pixel equivalent of 0.1198 mm / pixel and measurement range of 0.1198 ~ 42.169 mm is got by calibration experiment, analyzing experimental data, measurement accuracy reaches ± 0.09 mm. Instrument work properly and meet the design requirements in a laboratory environment.
Extracting Geometric Edges from 3D Point Clouds Based on Normal Vector Change
Authors: Li Jia , Lin Huan , Zhang Duo Qiang , Xue Xiao Lu
Published: June 2014

Normal vector of 3D surface is important differential geometric property over localized neighborhood, and its abrupt change along the surface directly reflects the variation of geometric morphometric. Based on this observation, this paper presents a novel edge detection algorithm in 3D point clouds, which utilizes the change intensity and change direction of adjacent normal vectors and is composed of three steps. First, a two-dimensional grid is constructed according to the inherent data acquisition sequence so as to build up the topology of points. Second, by this topological structure preliminary edge points are retrieved, and the potential directions of edges passing through them are estimated according to the change of normal vectors between adjacent points. Finally, an edge growth strategy is designed to regain the missing edge points and connect them into complete edge lines. The results of experiment in a real scene demonstrate that the proposed algorithm can extract geometric edges from 3D point clouds robustly, and is able to reduce edge quality’s dependence on user defined parameters.
Hand Detection with Dominant Pose Recognition Using EOH and SVM
Authors: Oh Chi Min , Lee Seok Jin , Lee Chil Woo
Published: June 2014

In this paper we propose a method of vision-based hand detection. Since the pose space of articulated is infinite and it is not feasible to train a classifier for the recognition of all hand poses to detect hand areas. Therefore we assume that it is rather better to detect only one dominant hand pose. To do so after hand skin color segmentation, each interest region of hand area in the given image is validated that the shape of hand region is similar to the dominant pose. The proposed system has the process of two steps; hand candidate detection and dominant pose recognition using EOH feature and SVM classifier. The experimental result shows that the proposed method works very effectively with very low false negative rate 0.6%.
Research on Issues of across Border Area in Network Games
Authors: Wang Hui Bai , Niu Xiao Hui
Published: June 2014

In this paper we conduct a study on the issues that the consistency and migration of game object in the border area of game scene. We put forward a method to deal with the problems. And it shows that the method is feasible and effective through practice.
An Improved Unambiguous Tracking Technique for CBOC Signals
Authors: Liu Hao , Li Bing Bing , Tong Zhao , Hui Yong Tao , Zhong Xing Wang
Published: June 2014

The autocorrelation function of Composite BOC(CBOC) signals has many side-peaks, which leads to the ambiguous problem. To solve this problem, an improved two-stage unambiguous tracking scheme is proposed in this paper. In the first stage, an unambiguous correlation function with narrow main peak is constructed by combining four out of twelve sub-correlation functions. In the second stage, by adding the rest of sub-correlation functions, the final correlation function with sharper and higher main-peak is developed based on the preparatory function from the first step. Numerical results demonstrate that compared to the original methods, the proposed scheme has a better tracking performance and can effectively suppress the short delay multipath.
A Distributed DC Power Devise Based on DSP
Authors: Zhou Zhao Xia , Nie Hui Xian , Lu Xian Jin
Published: June 2014

The adjustable high-power distributed DC power supply controlled by DSP presented in this article is a new type of electronic power supply. Considering the features of modern power system, this article discusses and compares the principles of technical design and application of the adjustable high-power distributed DC power supply controlled by DSP with those of traditional DC power supply. The result suggests that the adjustable high-power distributed DC power supply controlled by DSP is easy to install, energy-saving and environment-friendly. It also has the characteristics of lower cost and higher performance.
Modeling and Simulation of Motor Discrete Variable Frequency Soft Starting Based on the Variable Reactance
Authors: Song Xing Yu , Chen Jing , Deng Shi Jie , Yuan You Xin , Wang Qing
Published: June 2014

The started motors are characterized by the low staring torque and large currents when the motors draw the heavy-loads. Therefore, a method of motor discrete variable frequency soft starting based on the variable reactance is presented in this paper [1,2]. According to the topological structure and working principle of motor discrete variable frequency soft starting based on the variable reactance, the simulation model of the system has been set up by the Matlab/Simulink tool. Simulation results show that the motor starters developed with this method have been successfully applied to the loads of the drive equipment in the kiln, coal grinding mill or the mine. It can improve the starting performance when the motors draw the heavy-loads., save energy, stabilize the voltage of the power supply network.
Research on 5V Internal Power Supply Circuit of Switching Power Supply
Authors: Shao Zhu Lei
Published: June 2014

In order to guarantee the stability working of internal circuit of switching power supply, an internal power supply circuit with stabilization output was designed in this paper. Based on the voltage stabilization principle of zener diode, the internal power supply circuit put the high input voltage into 5v output voltage. Because of using module circuit, the circuit structure is simplified effectively. Based on 0.35um BCD technology, the internal power supply circuit was built in PSPICE. According to the experimental result, the internal power supply circuit can output stably in different input voltage and environmental temperature.
Research on Design of Virtual Maintenance Training System for Electronic Equipment
Authors: Wang Yan Hui , Mao Jian Zhou , Zhang Xin
Published: June 2014

In order to better solving the problem of electronic equipment maintenance training, promoting the level of management and usage to electronic equipment. The design method of virtual maintenance training system for electronic equipment is discussed in this paper based on virtual reality technology. Simulation results show that the system can well implement virtual maintenance training for the electronic equipment, and has certain reference value to develop other relevant system.
The Design of Freeform Surface Fresnel Lens Used for LED Uniform Illumination
Authors: Dai Yi Dan , Qu En Shi , Ren Li Yong , Du Xin Chao , Ju Hai Juan
Published: June 2014

This paper presents a new kind of light emitting diode(LED) secondary light distribution lens which adopts the type of Fresnel lens surface. The research purpose of this paper is to improve the LED heat dissipation efficiency of the secondary light distribution lens and the light efficiency, so as to prolong the service life of the LED. In this paper, we use the numerical method for solving the partial differential equation to establish a freeform surface lens which could produce uniform illumination, then the innovative method of combine the Fresnel lens structure with freeform surface lens was proposed. The design of freeform surface Fresnel lens allows dramatically cut the thickness of the lens (as well as the weight and volume) , it can solve the problem of difficulty in heat dissipation. By comparing the ray tracing simulation results of original freeform surface lens and freeform surface Fresnel lens in optical simulation software, experiments show that the latter not only shows the same degree of illumination uniformity, but also greatly reduced the thickness of the lens.
The Theory and Experimental Study on the Long-External Cavity Semiconductor Lasers
Authors: Qi Chang Jian , Zhao Tong Gang
Published: June 2014

Long-External Cavity Laser (L-ECL) is a kind of new and promising type laser because of its dynamic single mode performance. In this paper, firstly, the theory model of L-ECL is discussed; Secondly, the influence of coupling coefficient on the threshold gain of L-ECL is studied based on equivalent external cavity theory; Thirdly, utilizing the theory of equivalent cavity length, combined rate equations, the high frequency response characteristic of L-ECL is analyzed; Lastly, optical spectrums of L-ECL on different grating peak reflectivity are obtained by experiment.
Theoretical Studies of Novel High Power Millimeter Generator Based on Vacuum Electron Devices
Authors: Zhang Hai , Zhang Wei Guo , Shao Yang Zhou , Wang Jian Guo
Published: June 2014

New micromachining techniques now provide the opportunity to fabricate vacuum electron devices with dimensions suitable for operation in the terahertz region of the electromagnetic spectrum. In this paper, results of theoretical and numerical simulation studies of a MW-class, large diameter terahertz backward wave oscillator are presented. A novel full electromagnetic particle-in-cell simulation tool UNIPIC is also introduced. With this method, we studied the device at the frequency of 0.14 THz. It is found that the steady-state, single-frequency operation in this oversized situation could be realized by the property of surface wave near the upper cutoff area.
Effect of Corrosion on the Tensile Property of Austenised AISI 1040 Steel Exposed to Stagnant Seawater
Authors: Georgina Unueroh Ufuoma , Onyekpe Basil
Published: June 2014

Corrosion is a major problem all over the world. A lot of researches on corrosion are ongoing all over the world and will continue to go on. This paper investigates the effect of corrosion on the tensile properties of AISI 1040 steel in seawater. The samples were austenised at 8300C, 9300C, and 10300C, while some were not. The austenised samples were quenched in water and tempered at 5000C. The samples were further machined into tensile test specimens and then exposed to stagnant aerated seawater. Two samples each from each austenised temperature were tested using a tensile test machine at every 15-days interval, for a duration of 90 days. Some of the fracture surfaces were examined using scanning electron microscope. The results shows a 25% decrease in tensile strength for as received sample, 20.1% decrease for samples austenised at 8300C, 20.9% decrease for samples austenised at 9300C and 22.4% decrease for samples austenised at 10300C at the end of the 90thday.
The Design and Construction of a 2kVA Inverter with Automatic Timing Capability
Authors: Apeh S.T. , Omoifo O.I.
Published: June 2014

This work develops a 2KVA inverter with timing capability for load supply.The development of timing-capable inverter draws from a DC input which could be a solar/deep cycle battery source. Public power supply could be used to charge the battery. The inverter used the pulse width modulation (PWM) approach and used the SG3524N IC as the Pulse Width Modulator (PWM).Dual channel MOSFETs are supplied current of 10ms duration every 20ms and are used to alternately supply the primary windings of a step up transformer thereby producing an AC in the secondary of the transformer. A step-down transformer, bridge rectifier, and the pulse width modulator were used to provide voltage regulation of the output supply to the load. A keypad, a GDM1602A LCD screen and a PIC16F84A microcontroller were employed in the timing control of the voltage from the output of the inverter. Relays were employed in switching the voltage to the output based on the timing algorithm from the microcontroller. A prototype 2kVA inverter with timing was designed and implemented with a satisfactory output and suitable timing control.
A Novel Deformation Prediction Model for Mine Slope Surface Using Meteorological Factors Based on Kernel Extreme Learning Machine
Authors: Du Sun Wen , Zhang Jin , Deng Zeng Bing , Li Jing Tao
Published: June 2014

Extreme learning machine (ELM), as an emergent technique for training feed-forward neural networks, has shown good performance on various learning domains. This work evaluates the effectiveness of a new Gaussian kernel function-based extreme learning machine (KELM) algorithm for the deformation prediction of mine slope surface utilizing various kinds of meteorological influence factor data including the temperature, atmospheric pressure, cumulative rainfall, relative humidity and refractive index of the mining slope. The KELM model was applied to the deformation of Anjialing diggings, which is an open-pit mine of the China Coal PingShuo Group Co., Ltd. in China. The prediction performance on real data suggests that the proposed KELM model can effectively express the non-linear relationship between the mine open-pit slope surface deformation and various kinds of meteorological influence factors. The prediction results are compared with the most widely used algorithms – Support vector machine (SVM) and back-propagation neural networks (BP NN) in terms of the ease of use ( for example, the number of user-defined parameters), regression accuracy and computation cost. The comparison shows that the new algorithm is similar to SVM and BP NN but more accurate, and has notable lower computational cost and stronger generalization ability.
Electron-Energy-Loss Spectra of Free-Standing Silicene
Authors: Priede Luis M. , Meza-Montes Lilia
Published: June 2014

Silicene is becoming one of the most important two-dimensional materials. In this work, EEL Spectra were calculated for α-silicene (flat), and β-silicene (low-buckled, and theoretically the most stable). Band structures were determined using the semi-empirical Tight-Binding Method considering second nearest neighbors, sp3 model, Harrison's rule, and Slater-Koster parameterization. The dielectric function was calculated within the Random Phase Approximation and a space discretization scheme. We found that, compared to bulk Si, additional resonances appear which are red-shifted. Buckling gives rise to a richer structure at low energy.
Thermal Decomposition Synthesis and Assessment of Effects on Blood Cells and In Vivo Damages of Cobalt Ferrite Nanoparticles
Authors: Cotica Luiz F. , Freitas Valdirlei F. , Silva Daniel M. , Honjoya Karina , Honjoya Karen , Santos Ivair A. , Fontanive Verusca C.P. , Khalil Najeh M. , Mainardes Rubiana M. , Kioshima Erika S. , Guo Ruyan , Bhalla Amar S.
Published: June 2014

In the search to reduce the side effects, toxicity and assuring the desired effectiveness of the drugs, many efforts has been made to improve specific drugs’ delivery characteristics. Several carrier nanoparticles have been used to assist the drugs incorporation, absorption and transport through the bloodstream. However, most chemical synthesis routes are multistep and time-consuming treatments and, also, many carrier nanoparticles have toxic effects. In this work, we report a simple one-pot approach for the synthesis of CoFe2O4 nanoparticles (20 to 100 nm). The magnetic measurements revealed nanoparticles with a magnetic saturation nearly one third of that for bulk CoFe2O4. In vitro assays showed no hemolytic potential and negligible toxicity. By in vivo experiments using adult male mice we found no potential risk alterations by the nanoparticles administration. Therefore, the CoFe2O4 nanoparticles, synthesized by the current approach, can be a model drug-carrier, which makes them useful for the biomedical applications.
Performance Effect of ZnAl2O4 - SiO2 Thin Film for Wireless Patch Antenna Application
Authors: Zulfakar Mohd Syafiq , Abdullah Huda , Islam Mohammad Tariqul , Wan Jalal Wan Nasarudin , Zainuddin Zalita , Shaari Sahbudin
Published: June 2014

Polycrystalline of (1-x)ZnAl2O4 – xSiO2 compound with compositions of x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25 have been prepared using sol-gel method. Structural properties was investigated by atomic force microscopy (AFM) and x-ray diffractometer (XRD). The AFM images analysis showed that the surface roughness of the highest composition had rougher surface compared with other samples. XRD measurement indicated that the crystallite size also increased with average crystallite size around 18 nm with cubic phase had been found. The dielectric permittivity value were measured with frequency range of 1 Hz to 1 MHz. It is showed that the dielectric value decreased as the freqeuncy was applied to the samples. The performance of the patch antenna showed that the antenna resonated at 3.30 GHz and give-13.87 dB with frequency range about 2 – 4 GHz.
Effect on Adhesion to Tooth Structure for some Experimental Dental Adhesive System
Authors: Colceriu Loredana , Cimpean Sanda , Nicola Codruta , Sava Sorina , Trif Marcela , Buruiana Tinca , Moldovan Marioara , Silaghi-Dumitrescu Laura , Antoniac Aurora , Blajan Ana-Iulia , Prejmerean Cristina
Published: June 2014

The present study was conducted with the aim of evaluating and comparing the microleakage at the dentin and enamel/composite interfaces of two adhesive systems. The adhesives are: a new-developed experimental adhesive systems and OptiBond FL (Kerr Corp.) The new adhesive system was prepared for the composite material as three steps adhesive (etchant, primer and bonding). The bonding resin contains the base monomer that was present in the corresponding composite material, HEMA and TEGDMA as diluents. Twenty box-type Class V standardized cavities were prepared on the facial and oral surfaces of each tooth, with coronal margins in enamel and apical margins in cementum (dentin). The preparations were restored with two restorative materials a new experimental microfilled resin composites based on Bis-GMA analogue and hybrid resin composite Herculite XRV Ultra (Kerr Corp.). The teeth were thermocycled and immersed in 2% methyl blue solution for 24 hours. The specimens were sectioned buccolingually into 3 slices and the resulted sections were examined using a stereomicroscope under 40x magnification. The extent of dye penetration was measured in a quantitative manner. This measurement was converted into percentage using the formula described by Sano et al.I=p/Lx100. These percentage values were submitted to variance analyses (ANOVA) andttest at a p<0.05 level of significance. Scanning electron microscopy was used in order to see the interface between tooth and composite restoration. Significantly less microleakage was associated with the use of OptiBond FL adhesive system at the enamel surface. Between the enamel and the dentin margins no significantly statistical differences were found just for the experimental adhesive system. This adhesive containing water and ethanol as solvent performed significantly better at the dentin margins.
Material Defects in Ceramic Crowns Identification by Optical Coherence Tomography and MicroCT
Authors: Madaras Carla Andreea , Sinescu Cosmin , Negrutiu Meda Lavinia , Clonda Cezar Serban , Rominu Mihai , Ionita Ciprian , Antoniac Aurora , Podoleanu Adrian G.
Published: June 2014

Full ceramic crowns are considered revolutionary in developing the concept of aesthetic dentistry. Appreciate their aesthetic appearance particularly raise the cost prices, they do not ensure the risk of fractures and cracks which sometimes face the clinician after their insertion directly into the mouth. As a result of the fracture may occur between disputes team dentist-dental technician. The purpose of this study was to identify flaws of material included in the pottery table analyzing the full ceramic crowns using non-invasive technologies. As materials we use 25 full ceramic crowns (e. max, IVOCLAR) obtained through the technology of pressing were used for this study. Non-invasive methods used for this study were OCT and Micro CT. The OCT technology works in Time Domain, at 1300 nm and scan angle at 18 degrees, and for each sample scans were carried out in areas of maximum voltage. After the scans, we have been obtained through the stack of 500 slicers at a distance of 10 microns each other. A number of 17 samples of the total samples obtained exhibited defects in areas of major stress corresponding to the crown considered. As a result of defects discovered using the technology OCT it has considered necessary for validation them by employing the Micro CT technology. In conclusion, we consider that OCT technology can be considered an early diagnosis method of faults contained in the table structure of the ceramic crowns before inserting them in the oral cavity, by reducing the risks of a prosthetic treatment.
Metal-Ceramic Fixed Prosthodontics - An Obsolete Therapeutic Solution?
Authors: Jiménez-Castellanos Emilio
Published: June 2014

In this paper I will try to analyze the effectiveness of the techniques in metal-ceramic fixed prosthesis, recalling basics concepts like binding mechanisms between metal and ceramics or the minimum space requirements in the preparation of the abutment teeth to achieve adequate form and function. In a second stage I will try to establish their prognostic indications through these restorations based on survival rates published in systematic reviews and meta-analysis finally I will try to discuss different designs in fixed bridges and the possible indications of each one.
Bone Substitute Used in a Bilateral Calcaneal Fracture-Case Presentation
Authors: Lupescu Olivera , Nagea Mihail , Zamfirescu Dragos , Dimitriu Alexandru , Coltan Mihai , Ciurea Nicolae , Deaconescu Ciprian
Published: June 2014

Modern traumatology is characterized by high energy trauma, simultaneously affecting parts of the body especially in young patients. One of the most severe aspects resulting of high energy trauma is that of multiple skeletal injuries, with bone loss, which require complex treatment; this refers both to methods of filling the bone defects and to interdisciplinary approach whenever soft tissues are injured, as well. This case demonstrate the impact of modern approach in high energy trauma, with multiple aspects: bone substitutes as effective technique of bone filling and prevention of septic complications, as well as team work for concomitant treatment of associated injuries. The outcome of the patient, compared to the initial status, demonstrate the benefit of bone substitutes for a rapid recovery of trauma patients, with major impact on social and professional recovery.
Experimental Evaluation on Rat Model of Different Bioresorbable Materials Potentially Used as Orthopedic Biomaterials
Authors: Cristescu Ioan , Zamfirescu Daniel , Vilcioiu Daniel , Marina Lucian , Safta Forin
Published: June 2014

This study aims to present the preliminary studies related to the evaluation of the in vivo biocompatibility using the rat model of bioresorbable composite materials type collagen-tricalciumphophate and colagen-tricalcium phosphate-magnesium for potentially medical application in trauma surgery. These biomaterials could be used as short-term structural support for bone tissue defects and can be reabsorbed into the body after healing are being sought. For in-vivo evaluation of bioresorbable materials on 2 groups of twenty Wistar and brown Norway rats for a period of 18 months. We simulated tissue defects in different anatomical areas of the animals and these two types of biomaterials were implanted. The animals were evaluated periodically with clinical exams, laboratory tests (blood tests, histopatological tests, radiological control) and anatomical dissection for macroscopic examination of the tissues. After different times (3, 6 and18 months) of implantation we sacrificed the animals. We observed the resorbtion rate of the biomaterials into the tissues in conjunction with tissue regeneration. We also note the inflammatory response and foreign body reactions into the adjacent tissue, using histopathological examinations. Due to the reaction of the materials in contact with the bone narrow a layer of magnesium calcium phosphate was formed which contributes to the local tissue healing. Our preliminary investigation results on these materials demonstrate that all the implanted materials were absorbed in vivo without any pathological changes in the rat body. Other future researches will be made in order to validate these biomaterials as orthopedic biomaterials useful in bone defects regeneration.
Targeted Delivery of α-Galactosylceramide to CD8α+ Dendritic Cells Optimizes Type I NKT Cell–Based Antitumor Responses
Authors: Macho-Fernandez Elodie , Cruz Luis Javier , Ghinnagow Reem , Fontaine Josette , Bialecki Emilie , Frisch Benoit , Trottein François , Faveeuw Christelle
Published: June 2014

Immunotherapy aiming at enhancing innate and acquired host immunity is a promising approach for cancer treatment. The invariant NKT (iNKT) cell ligand α-galactosylceramide (α-GalCer) holds great promise in cancer therapy, although several concerns limit its use in clinics, including the uncontrolled response it promotes when delivered in a nonvectorized form. Therefore, development of delivery systems to in vivo target immune cells might be a valuable option to optimize iNKT cell–based antitumor responses. Using dendritic cell (DC)–depleted mice, DC transfer experiments, and in vivo active cell targeting, we show that presentation of α-GalCer by DCs not only triggers optimal primary iNKT cell stimulation, but also maintains secondary iNKT cell activation after challenge. Furthermore, targeted delivery of α-GalCer to CD8α+ DCs, by means of anti-DEC205 decorated nanoparticles, enhances iNKT cell–based transactivation of NK cells, DCs, and γδ T cells. We report that codelivery of α-GalCer and protein Ag to CD8α+ DCs triggers optimal Ag-specific Ab and cytotoxic CD8+ T cell responses. Finally, we show that targeting nanoparticles containing α-GalCer and Ag to CD8α+ DCs promotes potent antitumor responses, both in prophylactic and in therapeutic settings. Our data may have important implications in tumor immunotherapy and vaccine development.
An integrative review of South African cancer nursing research published from 2002–2012
Authors: Maree Johanna , Schmollgruber Shelley
Published: June 2014

Background: This integrative review aimed to quantify the publication output of South African cancer nursing research conducted between 2002 and 2012 and to identify key trends relevant to cancer nurse researchers.Objectives: To describe the publication output of cancer nursing research in terms of the journals of publication, authors, focus, participants and methods used, to explore whether the published work was funded and to assess the quality of the studies published.Methods: An integrative review was conducted using the key words South Africa in combination with cancer nursing and oncology nursing to search the databases Pubmed, PsycINFO, CINAHL, Sabinet, Web of Science, Medline and OvidSP. A data extraction sheet was developed to document the required information from each paper and all publications were reviewed independently by the authors.Results: A total of 181 publications for potential inclusion were identified and 26 papers were included in this review. Cervical cancer, specifically the prevention of this disease, was the most popular diagnostic focus and theme of investigation. Most of the studies were descriptive and none of the studies met the criteria of the highest quality.Conclusion: Nursing added to the body of knowledge regarding the primary and secondary prevention of cancer. There is a need for work on both men and women diagnosed withthe most common cancers, as well as the family and care giver. There is also a need for multidisciplinary work using complex interventions focusing on symptom management to improve patient outcomes.
Wound Care in Buruli Ulcer Disease in Ghana and Benin
Authors: Velding Kristien , Klis Sandor-Adrian , Abass Kabiru M. , Tuah Wilson , Stienstra Ymkje , van der Werf Tjip
Published: June 2014

Buruli ulcer (BU) is a disease affecting the skin, subcutaneous fat, and bone tissues. Wound care is important in the prevention of disabilities. Awareness of current wound care practices in BU-endemic regions is necessary for future wound care interventions. Thirty-one health care workers in Ghana and Benin were interviewed with a semi-structured interview, complemented by structural observations. Quantitative data were analyzed through t tests and one-way analysis of variance, and qualitative data through descriptive statistics. There appeared to be a general understanding of wound assessment. A large variety of different topical antiseptics was reported to be used, pressure irrigation was never reported. Gauze was the main dressing type and a moist environment was preferred, but could not be maintained. Bleeding and pain were observed frequently. Standard of wound care differed importantly between health care personnel and between institutions and adherence to World Health Organization guidelines was low.
Microbiological Evaluation of the Efficacy of Soapy Water to Clean Hands: A Randomized, Non-Inferiority Field Trial
Authors: Amin Nuhu , Pickering Amy J. , Ram Pavani K. , Unicomb Leanne , Najnin Nusrat , Homaira Nusrat , Ashraf Sania , Abedin Jaynal , Islam M. Sirajul , Luby Stephen P.
Published: June 2014

We conducted a randomized, non-inferiority field trial in urban Dhaka, Bangladesh among mothers to compare microbial efficacy of soapy water (30 g powdered detergent in 1.5 L water) with bar soap and water alone. Fieldworkers collected hand rinse samples before and after the following washing regimens: scrubbing with soapy water for 15 and 30 seconds; scrubbing with bar soap for 15 and 30 seconds; and scrubbing with water alone for 15 seconds. Soapy water and bar soap removed thermotolerant coliforms similarly after washing for 15 seconds (mean log10 reduction = 0.7 colony-forming units [CFU], P < 0.001 for soapy water; mean log10 reduction = 0.6 CFU, P = 0.001 for bar soap). Increasing scrubbing time to 30 seconds did not improve removal (P > 0.05). Scrubbing hands with water alone also reduced thermotolerant coliforms (mean log10 reduction = 0.3 CFU, P = 0.046) but was less efficacious than scrubbing hands with soapy water. Soapy water is an inexpensive and microbiologically effective cleansing agent to improve handwashing among households with vulnerable children.
Reactive uptake of N2O5 to internally mixed inorganic and organic particles: the role of organic carbon oxidation state and inferred organic phase separations
Authors: Gaston C. J. , Thornton J. A. , Ng N. L.
Published: June 2014

Abstract. We measured N2O5 reactive uptake onto mixed organic/inorganic submicron particles using organic compounds with a variety of oxidation states (using mainly atomic O : C ratios as a proxy) and molecular weights. The organic mass fraction, organic molecular composition, and relative humidity (RH) were varied to assess their effects separately on the N2O5 uptake coefficient, γ(N2O5). At a constant RH, mixtures of organic components having an O : C < 0.5 with ammonium bisulfate significantly suppressed the uptake of N2O5(g) compared to pure ammonium bisulfate, even at small organic mass fractions (e.g., ≤ 15%). The effect of the organic component became less pronounced at higher RH. In general, highly oxygenated organic components (O : C > 0.8) had a smaller or even negligible impact on N2O5(g) uptake at all RHs probed; however, a few exceptions were observed. Notably, γ(N2O5) for mixtures of ammonium bisulfate with polyethylene glycol (PEG), PEG-300 (O : C = 0.56), decreased nearly linearly as the PEG mass fraction increased at constant RH until leveling off at the value measured for pure PEG. The response of γ(N2O5) to increasing PEG mass fraction was similar to that measured on ambient atmospheric particles as a function of organic mass fraction. The effects of the organic mass fraction on γ(N2O5), for mixtures having an O : C < ~0.8, were best described using a standard resistor model of reactive uptake assuming the particles had an RH-dependent inorganic core–organic shell morphology. This model suggests that the N2O5 diffusivity and/or solubility in the organic layer is up to a factor of 20 lower compared to aqueous solution particles, and that the diffusivity, solubility, and reactivity of N2O5 within organic coatings and particles depend upon both RH and the molecular composition of the organic medium. We use these dependencies and ambient measurements of organic aerosol from the global aerosol mass spectrometry (AMS) database to show that the typical impact of organic aerosol components is to both uniformly decrease γ(N2O5), by up to an order of magnitude depending on the RH, organic mass fraction, and O : C ratio, and to induce a stronger dependence of γ(N2O5) upon RH compared to purely inorganic aqueous solutions.
A pathway analysis of global aerosol processes
Authors: Schutgens N. A. J. , Stier P.
Published: June 2014

Abstract. We present a detailed budget of the changes in atmospheric aerosol mass and numbers due to various processes: emission, nucleation, coagulation, H2SO4 condensation and in-cloud production, ageing and deposition. The budget is created from monthly-averaged tracer tendencies calculated by the global aerosol model ECHAM5.5-HAM2 and allows us to investigate process contributions at various length- and time-scales. As a result, we show in unprecedented detail what processes drive the evolution of aerosol. In particular, we show that the processes that affect aerosol masses are quite different from those affecting aerosol numbers. Condensation of H2SO4 gas onto pre-existing particles is an important process, dominating the growth of small particles in the nucleation mode to the Aitken mode and the ageing of hydrophobic matter. Together with in-cloud production of H2SO4, it significantly contributes to (and often dominates) the mass burden (and hence composition) of the hydrophilic Aitken and accumulation mode particles. Particle growth itself is the leading source of number densities in the hydrophilic Aitken and accumulation modes, with their hydrophobic counterparts contributing (even locally) relatively little. As expected, the coarse mode is dominated by primary emissions and mostly decoupled from the smaller modes. Our analysis also suggests that coagulation serves mainly as a loss process for number densities and that, relative to other processes, it is a rather unimportant contributor to composition changes of aerosol. The analysis is extended with sensitivity studies where the impact of a lower model resolution or pre-industrial emissions is shown to be small. We discuss the use of the current budget for model simplification, prioritisation of model improvements, identification of potential structural model errors and model evaluation against observations.
Clues for a standardised thermal-optical protocol for the assessment of organic and elemental carbon within ambient air particulate matter
Authors: Chiappini L. , Verlhac S. , Aujay R. , Maenhaut W. , Putaud J. P. , Sciare J. , Jaffrezo J. L. , Liousse C. , Galy-Lacaux C. , Alleman L. Y. , Panteliadis P. , Leoz E. , Favez O.
Published: June 2014

Abstract. Along with some research networking programmes, the European Directive 2008/50/CE requires chemical speciation of fine aerosol (PM2.5), including elemental (EC) and organic carbon (OC), at a few rural sites in European countries. Meanwhile, the thermal-optical technique is considered by the European and US networking agencies and normalisation bodies as a reference method to quantify EC–OC collected on filters. Although commonly used for many years, this technique still suffers from a lack of information on the comparability of the different analytical protocols (temperature protocols, type of optical correction) currently applied in the laboratories. To better evaluate the EC–OC data set quality and related uncertainties, the French National Reference Laboratory for Ambient Air Quality Monitoring (LCSQA) organised an EC–OC comparison exercise for French laboratories using different thermal-optical methods (five laboratories only). While there is good agreement on total carbon (TC) measurements among all participants, some differences can be observed on the EC / TC ratio, even among laboratories using the same thermal protocol. These results led to further tests on the influence of the optical correction: results obtained from different European laboratories confirmed that there were higher differences between OCTOT and OCTOR measured with NIOSH 5040 in comparison to EUSAAR-2. Also, striking differences between ECTOT / ECTOR ratios can be observed when comparing results obtained for rural and urban samples, with ECTOT being 50% lower than ECTOR at rural sites whereas it is only 20% lower at urban sites. The PM chemical composition could explain these differences but the way it influences the EC–OC measurement is not clear and needs further investigation. Meanwhile, some additional tests seem to indicate an influence of oven soiling on the EC–OC measurement data quality. This highlights the necessity to follow the laser signal decrease with time and its impact on measurements. Nevertheless, this should be confirmed by further experiments, involving more samples and various instruments, to enable statistical processing. All these results provide insights to determine the quality of EC–OC analytical methods and may contribute to the work toward establishing method standardisation.
Past freeze and thaw cycling in the margin of the El'gygytgyn crater deduced from a 141 m long permafrost record
Authors: Schwamborn G. , Meyer H. , Schirrmeister L. , Fedorov G.
Published: June 2014

Abstract. The continuous sediment record from Lake El'gygytgyn in the northeastern Eurasian Arctic spans the last 3.6 Ma and for much of this time permafrost dynamics and lake level changes have likely played a crucial role for sediment delivery to the lake. Changes in the ground-ice hydrochemical composition (δ18O, δD, pH, electrical conductivity, Na+, Mg2+, Ca2+, K+, HCO3-, Cl-, SO4-) of a 141 m long permafrost record from the western crater plain are examined to reconstruct repeated periods of freeze and thaw at the lake edge. Stable water isotope and major ion records of ground ice in the permafrost reflect both a synsedimentary palaeo-precipitation signal preserved in the near-surface permafrost (0.0–9.1 m core depth) and a post-depositional record of thawing and refreezing in deeper layers of the core (9.1–141.0 m core depth). These lake marginal permafrost dynamics were controlled by lake level changes that episodically flooded the surfaces and induced thaw in the underlying frozen ground. During times of lake level fall these layers froze over again. At least three cycles of freeze and thaw are identified and the hydrochemical data point to a vertical and horizontal talik refreezing through time. Past permafrost thaw and freeze may have destabilised the basin slopes of Lake El'gygytgyn and this has probably promoted the release of mass movements from the lake edge to the deeper basin as known from frequently occurring turbidite layers in the lake sediment column.