bluuebunny/crossref_metadata_2025 huggingface dataset:
Techniques for the Automated Segmentation of Lung in Thoracic Computed Tomography Scans
Authors: Sensakovic William F. , Armato Samuel G.
Published: June 2013

Computed Tomography (CT) is widely used to diagnose and assess thoracic diseases. The improved resolution of CT studies has resulted in a substantial increase of image data for analysis by radiologists. The time-consuming nature of this analysis motivates the application of Computer-Aided Diagnostic (CAD) methods to assist radiologists. Most CAD methods require identification of the lung within the patient images, a preprocessing step known as “lung segmentation.” This chapter describes an intensity-based lung segmentation method. The segmentation method begins with simple thresholding, and several image processing modules are included to improve segmentation accuracy and robustness. Common segmentation difficulties are discussed and motivate the inclusion of each module in the lung segmentation method. These modules will include brief explanations of common techniques (e.g., morphological operators) in addition to novel techniques developed specifically for lung segmentation (e.g., gradient correlation filters).
Image Processing for Localization and Parameterization of the Glandular Ducts of Colon in Inflammatory Bowel Diseases
Authors: Osowski Stanislaw , Kruk Michal , Koktysz Robert , Kurek Jaroslaw
Published: June 2013

This chapter presents the computerized system for automatic analysis of the medical image of the colon biopsy, able to extract the important diagnostic knowledge useful for supporting the medical diagnosis of the inflammatory bowel diseases. Application of the artificial intelligence methods included in the developed automatic system allowed the authors to obtain the unique numerical results, impossible for achieving at the visual inspection of the image by the human expert. The developed system enabled the authors to perform all steps in an automatic way, including the segmentation of the image, leading to the extraction of all glandular ducts, parameterization of the individual ducts and creation of the diagnostic features, as well as characterizing the recognition problem. These features put to the input of SVM classifier enable to associate them with the stage of development of the inflammation. The numerical experiments have shown that the system is able to process successfully the images at different stages of development of the inflammation. Its important advantage is automation of this very difficult work, not possible to be done manually, even by a human expert.
Color Image Segmentation of Endoscopic and Microscopic Images for Abnormality Detection in Esophagus
Authors: Hiremath P. S. , Humnabad Iranna Y.
Published: June 2013

The study of medical image analysis encompasses the various techniques for acquisition of images of biological structures pertaining to human body using radiations in different frequency ranges. The advancements in medical imaging over the past decades are enabling physicians to non-invasively peer inside the human body for the purpose of diagnosis and therapy. In this chapter, the objective is to focus on the studies relating to the analysis of endoscopic images of lower esophagus for abnormal region detection and identification of cancerous growth. Several color image segmentation techniques have been developed for automatic detection of cancerous regions in endoscopic images, which assists the physician for faster, proper diagnosis and treatment of the disease. These segmentation methods are evaluated for comparing their performances in different color spaces, namely, RGB, HSI, YCbCr, HSV, and CIE Lab. The segmented images are expected to assist the medical expert in drawing the biopsy samples precisely from the detected pathological legions. Further, various methods have been proposed for segmentation and classification of squamous cell carcinoma (SCC) from color microscopic images of esophagus tissue during pathological investigation. The efficacy of these methods has been demonstrated experimentally with endoscopic and microscopic image set and compared with manual segmentation done by medical experts. It is envisaged that the research in this direction eventually leads to the design and production of efficient intelligent computer vision systems for assisting the medical experts in their task of speedy accurate diagnosis of diseases and prescription of appropriate treatment of the patients.
Statistical Analysis for Radiologists’ Interpretations Variability in Mammograms
Authors: Azar Ahmad Taher
Published: June 2013

Conventional mammography is considered the modality of choice for the detection of breast cancer. The process involves a human radiologist visually diagnosing the mammogram, which causes limitations such as missing a cancer and/or diagnosing a false cancer. Another disadvantage of conventional mammography is the variability among screening radiologists in interpreting mammographic images. The objectives of this study are to verify this variability and to develop an image processing algorithm that can automatically detect benign tumors of the female breast. A sample of ten digital mammograms obtained from the MiniMIAS database was distributed to four different radiologists in order to verify the variability among them. Furthermore, three algorithms were developed in order to automatically detect benign tumors of the female breast. The proposed algorithms were based on combinations of certain statistical features and were tested on the same sample of images. Results showed that the detection mechanism using the proposed algorithms was acceptable despite the fact that they exhibited a few errors. It was concluded that the use of a combination of the mean and median statistical tools is effective in assisting radiologists in interpreting mammographic images containing benign tumors.
Study on Image Quality Assessment with Scale Space Approach Using Index of Visual Evoked Potentials
Authors: Hayashi Hidehiko , Minazuki Akinori
Published: June 2013

This chapter presents an objective assessment method of image quality using visual evoked potentials (VEPs) to image engineer field based on multi-disciplinarily approach such as knowledge of neurobiology, image recognition theory, or computer vision. The multi-disciplinarily based objective assessment method applies Gaussian scale-space filtering in order to define a scalar parameter to depict blur image. In the experiment, visual stimuli are provided by the scalar parameter, and subjects are detected using VEPs. Their VEPs are recoded during observation of the checkerboard pattern reversal (PR) stimuli, and are analyzed with a latency of about Negative 145 msec (N145) component. The result of the experiment was that latency of N145 components were long about10-20 msec when parameters were large vale (more blur). This result shows one example of availableness for the multi-disciplinarily based objective assessment of image quality by integrating the pattern reversal visual evoked potential (PR-VEP) and the scale-space theory.
Object Recognition via Contour Points Reconstruction Using Hurwitz - Radon Matrices
Authors: Jakóbczak Dariusz
Published: June 2013

Object recognition is one of the topics of artificial intelligence, computer vision, image processing and machine vision. The classical problem in these areas of computer science is that of determining object via characteristic features. Important feature of the object is its contour. Accurate reconstruction of contour points leads to possibility to compare the unknown object with models of specified objects. The key information about the object is the set of contour points which are treated as interpolation nodes. Classical interpolations (Lagrange or Newton polynomials) are useless for precise reconstruction of the contour. The chapter is dealing with proposed method of contour reconstruction via curves interpolation. First stage consists in computing the contour points of the object to be recognized. Then one can compare models of known objects, given by the sets of contour points, with coordinates of interpolated points of unknown object. Contour points reconstruction and curve interpolation is possible using new method of Hurwitz - Radon Matrices.
Feature Extraction Methods for Intrusion Detection Systems
Authors: Nguyen Hai Thanh , Franke Katrin , Petrovic Slobodan
Published: June 2013

Intrusion Detection Systems (IDSs) have become an important security tool for managing risk and an indispensable part of overall security architecture. An IDS is considered as a pattern recognition system, in which feature extraction is an important pre-processing step. The feature extraction process consists of feature construction and feature selection . The quality of the feature construction and feature selection algorithms is one of the most important factors that affects the effectiveness of an IDS. Achieving reduction of the number of relevant traffic features without negative effect on classification accuracy is a goal that largely improves the overall effectiveness of the IDS. Most of the feature construction as well as feature selection works in intrusion detection practice is still carried through manually by utilizing domain knowledge. For automatic feature construction and feature selection, the filter, wrapper, and embedded methods from machine learning are frequently applied. This chapter provides an overview of various existing feature construction and feature selection methods for intrusion detection systems. A comparison between those feature selection methods is performed in the experimental part.
Computer Vision for Learning to Interact Socially with Humans
Authors: Ramos da Silva Renato , Romero Roseli Aparecida Francelin
Published: June 2013

Computer vision is essential to develop a social robotic system capable to interact with humans. It is responsible to extract and represent the information around the robot. Furthermore, a learning mechanism, to select correctly an action to be executed in the environment, pro-active mechanism, to engage in an interaction, and voice mechanism, are indispensable to develop a social robot. All these mechanisms together provide a robot emulate some human behavior, like shared attention. Then, this chapter presents a robotic architecture that is composed with such mechanisms to make possible interactions between a robotic head with a caregiver, through of the shared attention learning with identification of some objects.
Human-Computer Interaction in Games Using Computer Vision Techniques
Authors: Devyatkov Vladimir , Alfimtsev Alexander
Published: June 2013

A primary goal of virtual environments is to support natural, efficient, powerful and flexible human-computer interaction. But the traditional two-dimensional, keyboard- and mouse-oriented graphical user interface is not well-suited for virtual environments. The most popular approaches for capture, tracking and recognition of different modalities simultaneously to create intellectual human-computer interface for games will be considered in this chapter. Taking into account the large gesture variability and their important role in creating intuitive interfaces, the considered approaches focus one’s attention on gestures although the approaches may be used also for other modalities. The considered approaches are user independent and do not require large learning samples.
Learning Robot Vision for Assisted Living
Authors: Yan Wenjie , Torta Elena , van der Pol David , Meins Nils , Weber Cornelius , Cuijpers Raymond H. , Wermter Stefan
Published: June 2013

This chapter presents an overview of a typical scenario of Ambient Assisted Living (AAL) in which a robot navigates to a person for conveying information. Indoor robot navigation is a challenging task due to the complexity of real-home environments and the need of online learning abilities to adjust for dynamic conditions. A comparison between systems with different sensor typologies shows that vision-based systems promise to provide good performance and a wide scope of usage at reasonable cost. Moreover, vision-based systems can perform different tasks simultaneously by applying different algorithms to the input data stream thus enhancing the flexibility of the system. The authors introduce the state of the art of several computer vision methods for realizing indoor robotic navigation to a person and human-robot interaction. A case study has been conducted in which a robot, which is part of an AAL system, navigates to a person and interacts with her. The authors evaluate this test case and give an outlook on the potential of learning robot vision in ambient homes.
Advances in Region-of-Interest Video and Image Processing
Authors: Grois Dan , Hadar Ofer
Published: June 2013

The advent of cheaper and more powerful devices with the ability to play, create, and transmit video content has led to a dramatic increase in the multimedia content distribution on both wireline and wireless networks. Also, the reduction of cost of digital video cameras along with the development of user-generated video sites (e.g., iTunes™, YouTube™) stimulated a new user-generated video content sector and made unprecedented demands for high-quality and low-delay video communication. The Region-of-Interest (ROI) is a desirable feature in many future scalable video coding applications, such as mobile device applications, which have to be adapted to be displayed on a relatively small screen; thus, a mobile device user may wish to extract and track only a predefined ROI within the displayed video. At the same time, other users having a larger mobile device screen may wish to extract other ROIs to receive higher video stream resolution. Therefore, to fulfill these requirements, it would be beneficial to simultaneously transmit or store a video stream in a variety of ROIs, as well to enable efficiently tracking of the predefined Region-of-Interest. This chapter presents recent advances in Region-of-Interest video and image processing techniques for multimedia applications, while making a special emphasis on a scalable extension of the H.264/AVC standard. The detailed observations and conclusions, which are presented in this chapter, are supported by authors’ personal experience in this field, thereby presenting a variety of experimental results.
Large Imagery on Small Screens
Authors: Rosenbaum René
Published: June 2013

With the focus being on digital imagery, this chapter proposes novel technology that is able to cope with the heterogeneous viewing hardware and user requirements in mobile services. With the aim to present an image at a detail level that is most appropriate for a given device and user, the main approach takes advantage of scalable image compression, transmission, and display. A scalable image is created once and multiply used for different kinds of devices and user requirements. By progressive refinement, the image is successively enhanced in detail until the device capabilities are used up to capacity. A framework that considers the most important resource types in mobile computing: computing power, bandwidth, and screen space, are introduced. Two different applications - on-the-fly adaptation at client side and profile-based adaptation at server side - are proposed leading to solutions for different application environments. Due to its flexibility and low-complexity, the proposed framework is a much more general solution compared to related approaches. This is underpinned by empirical results obtained from experiments and a discussion of the properties of the framework and its applications. Due to the novelty of the approach, some of the many possibilities for future work in this area are also discussed.
Automatic Organ Localization on X-Ray CT Images by Using Ensemble-Learning Techniques
Authors: Zhou Xiangrong , Fujita Hiroshi
Published: June 2013

Location of an inner organ in a CT image is the basic information that is required for medical image analysis such as image segmentation, lesion detection, content-based image retrieval, and anatomical annotation. A general approach/scheme for the localization of different inner organs that can be adapted to suit various types of medical image formats is required. However, this is a very challenging problem and can hardly be solved by using traditional image processing techniques. This chapter introduces an ensemble-learning-based approach that can be used to solve organ localization problems. This approach can be used to generate a fast and efficient organ-localization scheme from a limited number of training samples that include both original images and target locations. This approach has been used for localizing five different human organs in CT images, and the accuracy, robustness, and computational efficiency of the designed scheme were validated by experiments.
Object Analysis with Visual Sensors and RFID
Authors: Karmakar Gour , Dooley Laurence S. , Karmakar Nemai Chandra , Kamruzzaman Joarder
Published: June 2013

Object analysis using visual sensors is one of the most important and challenging issues in computer vision research due principally to difficulties in object representation, segmentation, and recognition within a general framework. This has motivated researchers to investigate exploiting the potential identification capability of RFID (radio frequency identification) technology for object analysis. RFID however, has a number of fundamental limitations including a short sensing range, missing tag detection, not working for all objects, and some items being just too small to be tagged. This has meant applying RFID alone has not been entirely effective in computer vision applications. To address these restrictions, object analysis approaches based on a combination of visual sensors and RFID have recently been successfully introduced. This chapter presents a contemporary review on these object analysis techniques for localisation, tracking, and object and activity recognition, together with some future research directions in this burgeoning field.
Replicating the Role of the Human Retina for a Cortical Visual Neuroprosthesis
Authors: Romero Samuel , Morillas Christian , Martínez Antonio , del Pino Begoña , Pelayo Francisco , Fernández Eduardo
Published: June 2013

Neuroengineering is an emerging research field combining the latest findings from neuroscience with developments in a variety of engineering disciplines to create artificial devices, mainly for therapeutical purposes. In this chapter, an application of this field to the development of a visual neuroprosthesis for the blind is described. Electrical stimulation of the visual cortex in blind subjects elicits the perception of visual sensations called phosphenes, a finding that encourages the development of future electronic visual prostheses. However, direct stimulation of the visual cortex would miss a significant degree of image processing that is carried out by the retina. The authors describe a biologically-inspired retina-like processor designed to drive the implanted stimulator using visual inputs from one or two cameras. This includes dynamic response modeling with minimal latency. The outputs of the retina-like processor are comparable to those recorded in biological retinas that are exposed to the same stimuli and allow estimation of the original scene.
Web 2.0, Neogeography, and Urban E-Governance
Authors: Warf Barney
Published: June 2013

Web 2.0 technologies, which allow interactions between the producers and consumers of information, have important implications for how urban spaces are designed and governed. Spatial information on the web has become increasingly wikified, so that non-planners may contribute data, photos, and opinions in a variety of ways, a process that labeled neogeography (and which is closely related to participatory GIS). For example, websites such as GoogleMaps have greatly democratized the process of constructing and using spatial data. This process implies that planners are no longer the privileged producers of information about urban space. A case study of Brión, Galicia, is offered to illustrate this process in practice. Web 2.0 and neogeography have greatly elevated the philosophical significance of planning information: rather than received wisdom, users may construct their own communities of truth. The chapter argues this process resembles Habermas’s notion of an ideal speech situation. The conclusion argues that Web 2.0 and the growth of neogeography imply that planning must be more inclusive and democratic in nature.
Tracking Public Participation in Urban Governance
Authors: Obermeyer Nancy
Published: June 2013

This chapter examines the use of GIS, geovisualization, and other geo-locational technologies and applications, including social networking websites and mobile phones associated with Web 2.0, as a tool kit for promoting democratization or leading to loss of data privacy and freedom, focusing on the relevant historical events in 2011 and the first half of 2012. The chapter begins by presenting a brief history of the GIS and society literature, including public participation GIS, volunteered geographic information, and geoslavery. The discussion covers both the rosy view (geospatial and Web 2.0 technologies as a democratizing force) and the gloomy perspective (these same technologies as tools of control based on data capture and loss of privacy). Underlying both of these views are scale and the ability to jump scales, which are examined through the lens of Kevin Cox’s (1998) “spaces of dependence and engagement.” Having laid this groundwork, the chapter considers events in the recent past, focusing first on the Arab Spring movements in Tunisia and Egypt and the Occupy movement in the U.S. as examples of the optimistic perspective. It then proceeds to discuss data capture from smart phones and cell phones as examples of the pessimistic view. The chapter concludes with a discussion of how individuals may enhance the democratization potential of geotechnologies and Web 2.0 while minimizing data capture, loss of spatial data privacy, and the harm that these can bring.
Social Media for Civic Engagement
Authors: Bryer Thomas A. , Nelson Kimberly L.
Published: June 2013

To explore the relationship between form of municipal government and deployment of social media tools for civic engagement, the authors conduct an analysis of a random set of purposively selected cities for content analysis of their social media tools. The authors use the seven forms of government identified by Nelson and Svara (2012) as the basis by which to select the sample cities. Across forms of government, there is no apparent pattern on deployment of social media tools for civic engagement. Municipalities of every form are using the tools, primarily Facebook and Twitter, and most, regardless of form, are not using the tools in a social manner. This finding is consistent with previous work by the authors and others. Important areas for future research are identified in a closing discussion.
E-Participation and Citizen Relationship Management in Urban Governance
Authors: Huebner Jim P.
Published: June 2013

Citizen relationship management (CiRM) is a combination of management approaches and information technologies for improving citizen services and citizen participation used at all levels of government. As an adaptation of private sector customer relationship management (CRM), CiRM is experiencing significant public sector adoption rates globally. However, while private sector CRM has demonstrated significant impact in the private sector, CiRM benefits are limited, and particularly lagging in the area of citizen e-participation in urban governance. This chapter provides an overview of the scope of CiRM functionality, with particular regard to the CRM origins and CiRM extensibilities, to develop a broader perspective of CiRM’s capacity for addressing e-participation. Developing this perspective further, theoretical and methodological approaches to e-participation are presented and evaluated in four categories: generic CiRM participation models, e-government CiRM, democratic CiRM, and strategic CiRM. Further research opportunities are highlighted within the context of emerging organizational, technological, and societal trends.
Policy Gadgets for Urban Governance in the Era of Social Computing
Authors: Ferro Enrico , Osella Michele , Charalabidis Yannis , Loukis Euripides
Published: June 2013

The chapter introduces the concept of policy gadgets that may be expressed as the combined use of computer simulations and social media in policymaking. Such a concept is exemplified by providing the description of an Italian campaign on telemedicine, launched by the regional government of Piedmont (IT) in the context of an international research project named PADGETS (www.padgets.eu). In addition, some preliminary results are presented, which are very encouraging. The use of such instruments in urban and regional policymaking may generate significant advantages in terms of conveying society’s inputs to policy makers, by providing them with a set of concise, fresh, and relevant data in a cost effective and easily understandable way.
Joint Radio Resource Management in Cognitive Networks
Authors: Bourdena Athina , Makris Prodromos , Skoutas Dimitrios N. , Skianis Charalabos , Kormentzas George , Pallis Evangelos , Mastorakis George
Published: June 2013

In this chapter, Joint Radio Resource Management (JRRM) issues in cognitive networks are discussed presenting the TV White Spaces (TVWS) spectrum exploitation use case. TVWS are portions of UHF spectrum, which will be released and interleaved according to the geographical region due to the gradual switch-off of analogue TV and the adoption of digital TV. With the availability of TVWS and their temporary lease, traditional network planning and RRM design rationale points need to be enhanced. This chapter provides state-of-the-art work for existing cognitive radio network architectures, while a reference architecture for commons and secondary TVWS trading is proposed. Subsequently, JRRM concepts for heterogeneous Radio Access Technologies’ extension over TVWS aiming to continuously guarantee the QoS, the network key performance indicators, and at the same time targeting the overall highest system capacity, are presented. Finally, a thorough classification of existing admission control and scheduling techniques are provided, outlining the need for including continuously more cognitive and context-aware features in JRRM algorithms being applicable in advanced Heterogeneous Networking (HetNet) environments.
Resource Allocation Strategies in Cognitive Radio Networks Under QoS Constraints
Authors: Vassaki Stavroula , Poulakis Marios I. , Panagopoulos Athanasios D. , Constantinou Philip
Published: June 2013

The rapid growth of spectral resources’ demands, as well as the increasing Quality of Service (QoS) requirements of wireless users have led to the necessity for new resource allocation schemes which will take into account the differentiated QoS needs of each wireless user. Towards this direction, the researchers have introduced the concept of effective capacity, which is defined as the maximum rate that the channel can support in order to guarantee a specified QoS requirement. This concept has been considered as a “bridge” among the physical layer characteristics and the upper-layer metrics of QoS. During the last years, it has been widely employed for resource allocation problems in various wireless networks leading to efficient mechanisms. This chapter focuses on the employment of the effective capacity theory in Cognitive Radio (CR) systems, presenting an extensive survey on QoS-driven resource allocation schemes proposed in the literature. Some useful conclusions are presented and future research directions on this subject are highlighted and discussed.
Spectrum Aggregation in Cognitive Radio Access Networks from Power Control Perspective
Authors: Chatzikokolakis Konstantinos , Spapis Panagiotis , Stamatelatos Makis , Katsikas George , Arapoglou Roi , Kaloxylos Alexandros , Alonistioti Nancy
Published: June 2013

Spectrum scarcity has motivated researchers and standardization bodies to work towards flexible spectrum usage. One of the solutions, Spectrum Aggregation, as proposed by 3GPP, is a way to increase wireless capacity through providing additional bandwidth to users. This chapter presents the Spectrum Aggregation scenario as it is proposed to be incorporated in LTE-Advanced. Furthermore, the interesting extensions of FP7 SACRA European research project regarding Spectrum Aggregation are described. The business and the functional aspects stemming from the incorporation of this solution in the LTE-Advanced networks are presented in detail. From the functionalities that are the cornerstone of the Spectrum Aggregation, namely spectrum sensing, admission control, and power control, the latter one is studied, which is not thoroughly investigated yet, and the authors present its key features. Moreover, a typical power control algorithm is described and enhanced with learning capabilities and policies in order to meet the requirements of the Spectrum Aggregation scenario; the simulation results highlight the need for power control schemes in Spectrum Aggregation cases.
Architectures and Information Signaling Techniques for Cognitive Networks
Authors: Kliazovich Dzmitry , Granelli Fabrizio , Fonseca Nelson , Bouvry Pascal
Published: June 2013

The introduction of self-awareness, self-management, and self-healing into networks leads to a novel paradigm known as cognitive networking. This chapter overviews recent developments of this concept, discussing possible cognitive node structure and candidate cognitive network architecture. It explains the functionality of cognitive algorithms and discusses opportunities for potential optimization. Furthermore, the concept of cognitive information services is introduced. Information signaling techniques are then classified, reviewed in details, and compared among them. Finally, the performance of cognitive communication protocols is presented for a choice of examples.
Security in Cognitive Radio Networks
Authors: Dabcevic Krešimir , Marcenaro Lucio , Regazzoni Carlo S.
Published: June 2013

While potentially solving the spectrum underutilization problem using methods such as dynamic and opportunistic spectrum access, Cognitive Radios (CRs) also bring a set of security issues and potential breaches that have to be addressed. These issues come from the two important capabilities implemented within CRs: their cognition ability and reconfigurability. This chapter focuses on identifying, presenting, and classifying the main potential security attacks and vulnerabilities, as well as proposing appropriate counter-measures and solutions for them. These are supplemented by simulation results and metrics, with the intention of estimating the efficiency of each of the observed attacks and its counter-measure. The presented simulations are performed in the proprietary C/C++ and Matlab/Simulink simulators. nSHIELD is a major ongoing European embedded systems security-related project, which is used to demonstrate the practicability of the potential implementation of the proposed countermeasures and solutions for the discussed security problems and issues.
The DEVS Formalism
Authors: Goldstein Rhys , Wainer Gabriel A. , Khan Azam
Published: June 2013

The DEVS formalism is a set of conventions introduced in 1976 for the specification of discrete event simulation models. This chapter explains the core concepts of DEVS by applying the formalism to a single ongoing example. First, the example is introduced as a set of informal requirements from which a formal specification is to be developed. Readers are then presented with alternative sets of modeling conventions which, lacking the DEVS formalism’s approach to representing state, prove inadequate for the example. The chapter exploits the DEVS formalism’s support for modular model design, as the system in the example is specified first in parts and later as a combination of those parts. The concept of legitimacy is demonstrated on various model specifications, and the relationship between DEVS and both object-oriented programming and parallel computing is discussed.
Evaluation and Comparison of Dimensional Accuracy of Newly Introduced Elastomeric Impression Material using 3D Laser Scanners: An in vitro Study
Authors: Yadav Naveen S , Jain Teerthesh , Pandita Amrita , Feroz SMA , LNU Pradeep , Diwedi Akankasha
Published: June 2013

Aim

Aim of the present study was to comparatively evaluate dimensional accuracy of newely introduced elastomeric impression material after repeated pours at different time intervals.

Materials and methods

In the present study a total of 20 (10 + 10) impressions of master model were made from vinyl polyether silicone and vinyl polysiloxane impression material. Each impression was repeatedly poured at 1, 24 hours and 14 days. Therefore, a total of 60 casts were obtained. Casts obtained were scanned with three-dimensional (3D) laser scanner and measurements were done.

Results

Vinyl polyether silicone produced overall undersized dies, with greatest change being 0.14% only after 14 days. Vinyl polysiloxane produced smaller dies after 1 and 24 hours and larger dies after 14 days, differing from master model by only 0.07% for the smallest die and to 0.02% for the largest die.

Conclusion

All the deviations measured from the master model with both the impression materials were within a clinically acceptable range.

Clinical significance

In a typical fixed prosthodontic treatment accuracy of prosthesis is critical as it determines the success, failure and the prognosis of treatment including abutments. This is mainly dependent upon fit of prosthesis which in turn is dependent on dimensional accuracy of dies, poured from elastomeric impressions.

How to cite this article

Pandita A, Jain T, Yadav NS, Feroz SMA, Pradeep, Diwedi A. Evaluation and Comparison of Dimensional Accuracy of Newly Introduced Elastomeric Impression Material using 3D Laser Scanners: An in vitro Study. J Contemp Dent Pract 2013;14(2):265-268.
Evaluation of Effect of Different Cavity Disinfectants on Shear Bond Strength of Composite Resin to Dentin using Two-Step Self-Etch and One-Step Self-Etch Bonding Systems: A Comparative in vitro Study
Authors: Bhandary Shreetha , Reddy M Surya Chaitanya , Mahesh MC , Pramod J , Shetty Ashwija
Published: June 2013

Aim and objectives

To evaluate the effect of 2% chlorhexidine, 2% sodium hypochlorite, 3% hydrogen peroxide on shear bond strength of composite resin to dentin using two-step and onestep self-etch bonding systems and to study the mode of failure of specimens under stereomicroscope.

Materials and methods

Eighty extracted sound human posterior teeth were used. The occlusal surfaces were ground to expose the dentin and were then randomly divided into 4 main groups. In group I, no cavity disinfectant was used and served as control. In groups II, III, IV, 2% chlorhexidine, 2% sodium hypochlorite and 3% hydrogen peroxide were used as cavity disinfectants respectively. Each group was then divided into two subgroups of 10 teeth each according to the bonding agent used, two-step self-etch (Adper SE Plus) and one-step self-etch (Adper Easy One) respectively. A transparent cylindrical plastic tube was loaded with microhybrid composite and placed over the dentin and light cured for 40 seconds. The specimens were subjected to shear stress in the universal testing machine.

Results

Pretreatment with 2% chlorhexidine, 2% sodium hypochlorite and 3% hydrogen peroxide, had a negative effect on the shear bond strength of self-etching bonding systems.

Conclusion

The highest bond strength was found in 2% chlorhexidine group followed by 2% sodium hypochlorite group and the lowest bond strength was found in 3% hydrogen peroxide group.

Clinical significance

All three cavity disinfectants used in this study reduced the shear bond strength and hence should be used with caution.

How to cite this article

Reddy MSC, Mahesh MC, Bhandary S, Pramod J, Shetty A. Evaluation of Effect of Different Cavity Disinfectants on Shear Bond Strength of Composite Resin to Dentin using Two-Step Self-Etch and One-Step Self-Etch Bonding Systems: A Comparativein vitroStudy. J Contemp Dent Pract 2013;14(2):275-280.
Mineral Oil—A Biofriendly Substitute for Xylene in Deparaffinization: A Novel Method
Authors: Premalatha BR , Indu M
Published: June 2013

Background

In routine histopathology, xylene has been used in tissue processing and staining. Presently health hazards of xylene are well documented and a safer substitute is an absolute necessity.

Aim

The present study was conducted to evaluate the efficacy of mineral oil as a deparaffinizing agent when compared to that of xylene by using hematoxylin and eosin (H&E) staining.

Materials and methods

Thirty paraffin-embedded tissue blocks were randomly selected and two sections were taken from each block. Thirty sections were stained with conventional H&E method (group A) using xylene as deparaffinizing agent and 30 were stained with xylene free method using refined mineral oil (group B). Sections were blinded and analyzed by two pathologists using the parameters of uniformity, clarity and intensity of nuclear and cytoplasmic staining respectively (satisfactory = score 1, unsatisfactory = score 0). Score „d 4 was considered to be adequate for diagnosis.

Results

100% of sections in group A and 93.3% of sections in group B were adequate for diagnosis (p-value 0.150).

Conclusion

The study recommends refined mineral oil as a biofriendly and effective xylene substitute in deparaffinization of tissue sections.

How to cite this article

Premalatha BR, Patil S, Rao RS, Indu M. Mineral Oil—A Biofriendly Substitute for Xylene in Deparaffinization: A Novel Method. J Contemp Dent Pract 2013;14(2):281-286.
Oral Manifestations of Systemic Alterations in Early Childhood
Authors: Padovani Maria Cristina Ramos Lima , Barbosa Patricia Silva , Baeder Fernando , de Sant'Anna Giselle Rodrigues , Santos Maria Teresa Botti Rodrigues , Guaré Renata Oliveira
Published: June 2013

Aim

This study aimed to describe certain common oral manifestations during early childhood that should be known by the pediatric dental surgeon.

Background

The correct diagnosis and treatment of oral manifestations during early childhood is important for children's development. The pediatric dentist is responsible for maintaining oral health in children, since they change constantly during their development and growth.

Case report

Four cases of oral lesions are described, in which the diagnosis and related approach for each one is reported. The first was an acute primary herpetic gingivostomatitis, the second, pseudomembranous candidiasis, the third, chickenpox and the last was molluscum.

Conclusion

Professionals who treat children in this age group must be able to diagnose and treat common oral manifestations when necessary and should refer the child to a pediatrician for effective treatment if the presence of any systemic alteration is suspected.

Clinical significance

Pathognomonic signs of the most common oral manifestations in early childhood should be known by dentists to improve early diagnosis and proper management.

How to cite this article

Padovani MCRL, Barbosa PS, Baeder F, de Sant'Anna GR, Santos MTBR, Guaré RO. Oral Manifestations of Systemic Alterations in Early Childhood. J Contemp Dent Pract 2013;14(2):327-331.
Formation of aqueous-phase α-hydroxyhydroperoxides (α-HHP): potential atmospheric impacts
Authors: Zhao R. , Lee A. K. Y. , Soong R. , Simpson A. J. , Abbatt J. P. D.
Published: June 2013

Abstract. The focus of this work is on quantifying the degree of the aqueous-phase formation of α-hydroxyhydroperoxides (α-HHPs) via reversible nucleophilic addition of H2O2 to aldehydes. Formation of this class of highly oxygenated organic hydroperoxides represents a poorly characterized aqueous-phase processing pathway that may lead to enhanced SOA formation and aerosol toxicity. Specifically, the equilibrium constants of α-HHP formation have been determined using proton nuclear-magnetic-resonance (1H NMR) spectroscopy and proton-transfer-reaction mass spectrometry (PTR-MS). Significant α-HHP formation was observed from formaldehyde, acetaldehyde, propionaldehyde, glycolaldehyde, glyoxylic acid, and methylglyoxal, but not from methacrolein and ketones. Low temperatures enhanced the formation of α-HHPs but slowed their formation rates. High inorganic salt concentrations shifted the equilibria toward the hydrated form of the aldehydes and slightly suppressed α-HHP formation. Using the experimental equilibrium constants, we predict the equilibrium concentration of α-HHPs to be in the μM level in cloud water, but it may also be present in the mM level in aerosol liquid water (ALW), where the concentrations of H2O2 and aldehydes can be high. Formation of α-HHPs in ALW may significantly affect the effective Henry's law constants of H2O2 and aldehydes but may not affect their gas-phase levels. The photochemistry and reactivity of this class of atmospheric species have not been studied.
Modeling air pollution in Lebanon: evaluation at a suburban site in Beirut during summer
Authors: Waked A. , Seigneur C. , Couvidat F. , Kim Y. , Sartelet K. , Afif C. , Borbon A. , Formenti P. , Sauvage S.
Published: June 2013

Abstract. Beirut, the capital of Lebanon, which is located on the eastern shore of the Mediterranean basin, experiences high air pollution episodes. Annual average concentrations of coarse and fine particulate matter (PM2.5) as well as nitrogen oxides (NOx) often exceed the World Health Organization (WHO) guidelines. Therefore, improving air quality in this region is essential. The Polyphemus/Polair3D modeling system is used here to investigate air pollution episodes in Beirut during 2 to 18 July 2011. The modeling domain covers two nested grids of 1 and 5 km horizontal resolution over greater Beirut and Lebanon, respectively. The anthropogenic emission inventory was developed earlier (Waked et al., 2012). The Weather and Research Forecasting (WRF) model is used to generate the meteorological fields and the Model of Emissions of Gases and Aerosols from Nature (MEGAN) is used for biogenic emissions. The results of the study are compared to measurements from a field campaign conducted in the suburb of Beirut during 2–18 July 2011. The model reproduces satisfactorily the concentrations of most gaseous pollutants, the total mass of PM2.5 as well as PM2.5 elemental carbon (EC), organic carbon (OC), and sulfate. Ozone concentrations are overestimated and it appears that this overestimation results mainly from the boundary conditions.
The regime of desert dust episodes in the Mediterranean based on contemporary satellite observations and ground measurements
Authors: Gkikas A. , Hatzianastassiou N. , Mihalopoulos N. , Katsoulis V. , Kazadzis S. , Pey J. , Querol X. , Torres O.
Published: June 2013

Abstract. The regime of desert dust (DD) episodes over the broader Mediterranean basin is studied for the period 2000–2007. The novelty of this work lies in its complete spatial coverage of the region. An objective and dynamic algorithm has been set up, which uses daily measurements of various aerosol optical properties taken by different satellite databases, enabling the identification of DD episodes and their classification into strong and extreme ones. The algorithm's performance was tested against surface based (in situ) Particulate Matter (PM) and (columnar) sun-photometric AERONET measurements from stations distributed across the Mediterranean. The comparisons have shown the reasonable ability of the algorithm to detect the DD episodes taking place within the study region. The largest disagreements with PM data were found in summer and western Mediterranean, when African dust transport has a great vertical extent that cannot be satisfactorily captured by surface measurements. According to our results, DD episodes in the Mediterranean basin are quite frequent (up to 11.4 episodes/year) while there is a significant spatial and temporal variability in their frequency of occurrence and their intensity. Strong episodes occur more frequently in the western Mediterranean basin whilst extreme ones appear more frequently over central Mediterranean Sea areas. Apart from this longitudinal variation, there is a predominant latitudinal variability in both frequency and intensity, with decreasing values from south to north. A significant seasonal variation was also found for the frequency of DD episodes, with both strong and extreme episodes being more frequent during summer in the western Mediterranean basin, but during spring in its central and eastern parts. In most cases (>85%) the Mediterranean dust episodes last a bit longer than a day, although their duration can reach 6 days for strong episodes and 4 days for extreme episodes. A noticeable year by year variability was also found, especially for the frequency of the episodes. The spatial and temporal patterns of Mediterranean DD episodes can be explained based on surface pressure and precipitation spatio-temporal distribution patterns over the study region, as well as by the year by year variability of North Atlantic Oscillation (NAO). In this context, a decreasing frequency of appearance of DD episodes over the Mediterranean basin has been revealed over the period 2000–2007, especially over land surfaces, in line with decreasing NAO Index over the same period. Our findings demonstrate the reasonable ability to detect desert dust outbreaks in the Mediterranean basin from satellites.
Seasonality of CO2 in coastal oceans altered by increasing anthropogenic nutrient delivery from large rivers: evidence from the Changjiang–East China Sea system
Authors: Chou W.-C. , Gong G.-C. , Cai W.-J. , Tseng C.-M.
Published: June 2013

Abstract. Model studies suggested that human-induced increase in nutrient load may have stimulated primary production and thus enhanced the CO2 uptake capacity in the coastal ocean. In this study, we investigated the seasonal variations of the surface water's partial pressure of CO2 (pCO2sw) in the highly human-impacted Changjiang–East China Sea system between 2008 and 2011. The seasonality of pCO2sw has large spatial variations, with the largest extreme of 170 ± 75 μatm on the inner shelf near the Changjiang Estuary (from 271 ± 55 μatm in summer to 441 ± 51 μatm in autumn) and the weakest extreme of 53 ± 20 μatm on the outer shelf (from 328 ± 9 μatm in winter to 381 ± 18 μatm in summer). During the summer period, stronger stratification and biological production driven by the eutrophic Changjiang plume results in a very low dissolved inorganic carbon (DIC) in surface waters and a very high DIC in bottom waters of the inner shelf, with the latter returning high DIC to the surface water during the mixed period. Interestingly, a comparison with historical data shows that the average pCO2sw on the inner shelf near the Changjiang Estuary has decreased notably during summer, but has increased during autumn and winter from the 1990s to the 2000s. We suggest that this decadal change is associated with recently increased eutrophication. This would increase both the photosynthetic removal of DIC in surface waters and the respiratory release of DIC in bottom waters during summertime, thereby returning more DIC to the surface during the subsequent mixing seasons and/or episodic extreme weather events (e.g., typhoons). Our finding demonstrates that increasing anthropogenic nutrient delivery from a large river may enhance the sequestration capacity of CO2 in summer but may reduce it in autumn and winter. Consequently, the coastal ocean may not necessarily take up more atmospheric CO2 in response to increasing eutrophication, and the net effect largely depends on the relative timescale of air–sea gas exchange and offshore transport of the shelf water. Finally, the case we report for the Changjiang system may have general ramifications for other eutrophic coastal oceans.