bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatal consequences caused by prolonged chloroform inhalation in a child
Authors: Milic Miroslav , Antovic Aleksandra , Trandafilovic Milena , Zdravkovic Miodrag
Published: April 2018

Introduction. Chloroform intoxication as a result of inhalation is usually associated with occupational exposure. Fatal cases of accidental and intentional chloroform poisoning are extremely rare. The aim of this work was to report a case with fatal consequences caused by prolonged chloroform inhalation in a child. Case outline. We report a case of a three-month-old child found dead by its mother in their home. Investigation provided the data about two refrigerators in the house, which were not entirely functional, and were filled with a refrigerant based on chloroform, and about a recent house spraying with a pesticide also based on chloroform. Forensic autopsy was performed the following day. Autopsy established the existence of malnutrition, dehydration, brain and lungs edema, the presence of very scarce contents in the digestive tract, and the enlargement of the abdominal lymph nodes. The initial stage of liver degeneration was noted on histopathological examination. Chemical-toxicological analysis of organ tissue samples (brain, lungs, spleen, liver with gall bladder, kidney and bladder, stomach, small and large intestine) performed using the techniques of headspace gas chromatography with mass detector, confirmed chloroform poisoning. Conclusion. The emaciation underlying the dysfunction of organ systems provided a grim frame for a child to succumb to chloroform toxicity. The proper use and maintenance of domestic appliances, and careful application of chemical agents indoors is an imperative, especially in the vicinity of children. Low levels of chloroform inhaled from the room air may have fatal consequences in a susceptible individual.
Barriers to Openness: The Case of Technology Development Zone Companies
Authors: Şimşek Kübra , Yıldırım Nihan
Published: April 2018

Open Innovation promises higher outcomes
from innovation processes through collaboration and sharing knowledge and the
intellectual assets. Inclusion of suppliers, customers or users, partners, and
even competitors in innovative processes can help to overcome constraints on
internal resources. For ICT companies that operate in eco-systems of technology
development zones (TDZ), open innovation approach becomes more critical mostly
due to the scale and experience constraints. To understand the barriers of open
innovation for ICT firms in TDZs can significantly help strategy and decision
makers in designing policies and actions to empower innovation processes in
order to overcome these barriers and hence to utilize open innovation for
higher competitiveness. Various researchers examined the challenges of open
innovation in various contexts, as well as the innovativeness and business
performances of TDZ companies. However, there is still a room for research on
exploring the dimensions of motives and barriers of open innovation practices
of these companies. This study aims to explore the barriers for open innovation
in ICT TDZ companies through surveys and in-depth interviews that are carried
out in 102 ICT firms in TDZs in Turkey. By applying factor analysis, the main
barriers to openness are identified and relationships of these barriers with
the company’s characteristics explored. Findings reveal that the most
frequently perceived constraints are financial and administrative problems.
Türkiye’de Sağlık Harcamalarının Gelir Üzerindeki Etkisi: TR32 Bölgesi Örneğinde Eşbütünleşme Analizi
Authors: Alp Mustafa , Peker Osman
Published: April 2018

Bu çalışmada TR32 (Aydın, Denizli, Muğla)
illerinde yapılan sağlık harcamalarının, bu üç ilin gayri safi hasılasına
etkisi, 2006Q1:2015Q4 dönemi için Engle Granger eşbütünleşme yöntemiyle analiz
edilmiştir. Analiz sonucunda serilerin eş bütünleşik olduğu görülmüştür.
İncelenen bölge örneğinde sağlık harcamalarının gayri safi hasılaya olumlu
yönde katkı yaptığı bulgusu elde edilmiştir. Kısa dönem analizinde ise hata
düzeltme modelinin çalıştığı yani seriler arasında kısa dönemde meydana gelen
sapmaların uzun dönem denge düzeyine yakınsadığı belirlenmiştir.
Pro Und Kontra Für Einen Eu-Beitritt Der Türkei
Authors: Yılmaz Nihat
Published: April 2018

Die Höhe des Entwicklungsstandes in Europa, die
Überlegenheit in Technologie, Wissenschaft und Menschenrechte sind wichtige
Anzeige, die Europa anziehend zeigen. Aufgrund des starken Wunsches der Türkei
diese Anzeige zu erreichen, ist die Türkei seit ungefähr 150 Jahren im
Europäisierungsbestreben. Aber die Beziehungen zwischen der Türkei und der EU
sind im Allgemeinen sehr wechselhaft und schwankend. Sowohl inner- als auch
außerhalb der Türkei werden zu einem eventuellen EU-Beitritt verschiedene
Meinungen geäußert. Ziel dieses Artikels ist, dass die Argumente der
Befürworter und der Gegner des EU-Beitrittsprozesses der Türkei untersuchen.
Die Befürworter sehen den Beitrittsprozess als eine große Herausforderung mit
vielen Vorteilen für die EU, die Kontroversen verteidigen dagegen, dass die
Grenzen der Erweiterung überschritten werden.
Nuevos recursos y estrategias en el vínculo de la representación parlamentaria en América Latina / New resources and strategies in the link of parliamentary representation in Latin America
Authors: Valencia Escamilla Laura
Published: April 2018

El documento tiene por objetivo analizar cómo los recursos tecnológicos aplicados a la gestión legislativa inciden en la relación ciudadanos-representantes en la región latinoamericana. El estudio se elaboró con base en un análisis comparativo de las experiencias en los congresos latinoamericanos basado en tres criterios: 1) la rendición de cuentas vertical; 2) el acceso ciudadano a la información; y 3) el nivel de incidencia de participación ciudadana en las decisiones legislativas.  El primero se observa a partir de identificar los mecanismos institucionales para la mejora del equilibrio de poderes, así como la incidencia de los legisladores en el cargo a través de la reelección. El segundo elemento se analiza por medio de los diferentes informes regionales sobre transparencia legislativa y sistemas de información. Finalmente, la participación ciudadana, se verifica mediante la utilización de mecanismos de participación en la región.En el estudio fue posible identificar que el proceso de modernización legislativa a la que se sometieron la mayoría de los Congresos en América Latina, favoreció su gestión, el acceso a la información, la transparencia, y la participación ciudadana en las decisiones legislativas. Sin embargo, la introducción de los recursos tecnológicos, no fue suficiente para modificar las prácticas políticas, la representación ciudadana y la escasa rendición de cuentas que caracteriza a la región, lo que ha mantenido a los congresos latinoamericanos en una complicada crisis de credibilidad y confianza ciudadana.
La implementación del proceso penal acusatorio en Guerrero, México / The implementation of the accustive criminal process in Guerrero, México
Authors: Arcos Vélez Víctor Manuel
Published: April 2018

Las presiones internacionales del Plan Mérida (1990), el Consenso de Washington (1994) y las sentencias de la Comisión Interamericana de Derechos Humanos (2009) criticaron la ineficacia, colusión de autoridades y la responsabilidad del Estado mexicano por ser omisa ante actos de particulares o de autoridades que afectaron los derechos humanos y la dignidad de las personas, principalmente en asuntos de aplicación de la justicia penal, y que obligaron al Estado mexicano a cambiar su sistema procesal penal.Se considera que el cambio hacia una justicia penal más garantista se postergó por mucho tiempo debido a la característica autoritaria de nuestro régimen político. Los abusos policiales, la corrupción e ineficacia de nuestras instituciones de procuración y administración de justicia penal no son nada nuevo y estas prácticas indeseables deben terminar; pero la violencia y la inseguridad no será superada solo cambiando los sistemas procesales de justicia.
Three-phase four wire shunt active power filter based on Simplified Backstepping technique for DC voltage control
Authors: M. Dellahi  , Az. Mouhsen  , H. Maker  , A. Mouhsen  , E. Alameda Hernandez
Published: April 2018

This work presents a simulation of Three-Phase Four-Wire Shunt Active Power Filter (SAPF) destined to suppress harmonic currents generated by nonlinear loads. The SAPF guarantee also the compensation for unbalanced nonlinear load currents, reactive power and harmonic neutral current. The identification method is based on the synchronous reference frame. In order to have good performances of DC voltage control, simplified Backstepping control for three-Phase four-Wire (SAPF) system is proposed. Complete simulation of the resultant active filtering system validates the efficiency of the proposed simplified Backstepping control law over to the traditional control with PI controller.
Modeling of a New Super-Gain BJT and an innovative Low-loss AC Switch based on Gummel-Poon model
Authors: Z. Ren  , P. Wang  , A. Schellmanns  , N. Batut  , G. Goubard
Published: April 2018

This article gives a modeling method based on the Gummel-Poon model for the Super-Gain BJT developed in the GREMAN laboratory. First of all, the extraction principle, mathematical calculating method, and final extraction results of each model parameter will be presented. Secondly, the Gummel and Voltage-Current output curves for a single Super-Gain BJT, which are carried on in Pspice with the extracted parameters in the first part, will be drawn and be compared with experimentation results. At last, a new 600V AC switch that is composed of two single Super-Gain BJTs connected in anti series is simulated. To explain and reduce the error between the simulated results and experimental ones in hi-level injection, a new model with a dynamic resistance based on that of Gummel Poon is proposed and validated. Consequently, all of simulations have an error less than 10%, proving the good precision of the models as well as the characteristics of the new AC power switch.
DC Switchyard Configurations for the Integration of Distributed Energy Resources
Authors: A. Hermosilla  , D.M. Larruskain  , P. Eguia
Published: April 2018

HVDC supergrid must grow in an organized way. The objective of HVDC substations will be to integrate generation groups and occasionally connect them to the AC network. That way, all substations will not be identical and their relevance will not be the same. In AC substations, network topological changes are made to limit the short circuit current contributions, perform load distributions and allow maintenance work when the application of restrictions is necessary, without compromising generation. These maintenance tasks should allow the exploitation of the network without making concessions on the stability of the system. DC networks do not require topological changes in the network to distribute loads, its utility would be reduced to facilitate maintenance tasks and minimize the possible effects of faults. However, it must be discussed which is the most suitable switchyard or whether more than one switchyard are required such as in AC networks. In the paper the usual topologies and switchyard configurations are analyzed and compared to determine if the architectures inherited from the AC grids can be used in the future HVDC supergrid. Several DC switchyard configurations are also discussed. Finally, the most suitable configurations are compared and applied to a study case.
Experimental performance of a solar thermal liquid desiccant air conditioning system – A review
Authors: S. Bouzenada
Published: April 2018

Solar energy may be the great option to provide the conditioned  air  in  summer,  as  solar  energy  available  in  plenty.Liquid  desiccant  air  conditioning  (LDAC)  system  using  solar energy  is  proposed  as  an  alternative  to  the  conventional vaporcompression  systems  due  to  its  advantage  in,  removing  the  air latent load, friendly to environment, removing of pollutants from the  process  air,  reduction  of  the  electrical  energy,  do  not  using the  harmful  refrigerants  and  protection  to  ozone  layer  depletion. In this paper, the recent works on solar driven liquid desiccant air conditioning system and its advantages are reviewed. The system may  offer  in  terms  of  energy  savings  are  underscored.  A  basic description  of  (LDAC)  system  is provided.  The  regeneration temperature  and  solar  collector  efficiency  are  developed  and  the analysis  highlights  the  performance  of  the  system.  The  literature review  has  highlighted  that  there  is  a  clear  need  for  research  in the  field  of  liquid  desiccant  air  conditioning  system  with  solar energy  in  many  buildings.  This  is  due  to  the  patent  operational advantages the system can deliver in terms of energy saving from 25   to   50%,   operating   costs   and   energy   security,   the low regeneration temperature.The objective of this paper review is to access    using    of    liquid    desiccant    based    air    conditioning, regenerated   by   eco-friendly   renewable   energy.   The   liquid desiccant  systems  present  multifunctional  properties  that  make them  particularly  interesting  in  several  fields  ofapplication. Electric  utilities  have  their  peak  loads  in  hot  summer  and  are often  barely  capable  of  meeting  the  demand,  with  brown-out situations. It is a good application for solar energy due to the fact that the greatest demand for air conditioning occurs during times of highest insolation.
Wavelet Based Energy Extraction Method for Determining Power Quality Disturbances
Authors: Ç. Kocaman  , M. Ozdemir
Published: April 2018

In this paper, energy of wavelet coefficients are used for determining power quality disturbances (PQD) which are important for power systems. These power quality disturbances are voltage with harmonics, transient and flicker. After analyzing energy coeffients based on wavelet transform, these PQD are compared with healty condition. 50 Hz pure sine is chosen as reference. These signals are generated by using MATLAB. Sampling frequency is 25.6 kHz. Energy distribution of detail coefficients are obtained by using 12 level Daubechies 4 discrete wavelet filter. Parseval theorem is applied to wavelet coefficients for obtaining energy distribution of detail coefficients of these relevant disturbances in different resolution levels. Satisfactory results are taken visually when examining energy distrubutions of these PQD. Also it is observed that these PQD can be distinguished visually when their amplitudes are increased. Energy coefficients of PQD and amplitude of PQD are in direct propotion.
A 380 V High Efficiency and High Power Density Switched-Capacitor Power Converter using Wide Band Gap Semiconductors
Authors: L. Fan  , A. Knott  , I. Jørgensen
Published: April 2018

State-of-the-art switched-capacitor DC-DC power converters mainly focus on low voltage and/or high power applications. However, at high voltage and low power levels, new designs are anticipated to emerge and a power converter that has both high efficiency and high power density is highly desirable. This paper presents such a high voltage low power switched-capacitor DC-DC converter with an input voltage up to 380 V (compatible with rectified European mains) and an output power experimentally validated up to 21.3 W. The wide band gap semiconductor devices of GaN switches and SiC diodes are combined to compose the proposed power stage. Their switching and loss characteristics are analyzed with transient waveforms and thermal images. Different isolated driving circuits are compared and a compact isolated half bridge driving circuit is proposed. The full-load efficiencies of 98.3% and 97.6% are achieved for the power stage and the complete power converter, without heatsink or airflow. The corresponding power densities are 7.9 W/cm3 and 2.7 W/cm3, based on boxed volumes, respectively.
Characterization of Non Intentional Conducted Emissions Up to 500 kHz in Urban Environment
Authors: I. Fernández  , M. Garcia-Plaza  , D. de la Vega  , A. Arrinda  , I. Angulo  , T. Arzuaga  , A. Fernandez Olivera
Published: April 2018

The current interest in Europe to extend the frequency range for Narrowband Power Line Communications up to 500 kHz requires a thorough characterization of the non intentional emissions in this frequency range. This paper presents results of field measurements carried out in a dense urban environment, where the electrical devices are quite numerous and located at a short distance from the smart meters, and therefore, the effects of the non-intentional emissions on Smart Grids communications may be noticeable. In the study, spectral and time characterization of the recorded data was performed according to CISPR specifications, and then compared to recommended limits for non-intentional emissions in this frequency range. Results show that the levels of the emissions above 150 kHz may exceed the recommended limits for spurious emissions in the frequency band, mainly near the smart metering devices, due to the nearness of different types of electrical devices connected to the grid. This work demonstrates the need of characterizing the non-intentional emissions up to 500 kHz for the proper performance of future Smart Grid applications in this frequency range.
Switched Reluctance Machine Modeling through Multilayer Neural Networks
Authors: A. C. F. Mamede  , J. R. Camacho  , R. E. Araújo
Published: April 2018

The work deals with the application of artificial neural networks (ANNs) in the modeling of switched reluctance machines (SRMs). The performance of a SRM is determined by its geometry, materials used and levels of excitation. In this way, this work investigates the influence of the stator and rotor back iron thickness in the performance of SRM. A multilayer neural network is proposed to learn the nonlinear characteristics of the motor. Data of flux linkages and torque are obtained through simulations of finite elements and used for ANN training. The algorithm developed in Octave allows the user to adjust the network parameters. The results presented confirm the feasibility of using ANN to establish a predictive model of SRM performance, thus enabling further investigation in the future.
Design and Synthesis of New Fullerene Derivatives for Organic Solar Cells
Authors: Jianping Lu  , Salima Alem  , Afshin Dadvand  , Jianfu Ding  , Ye Tao
Published: April 2018

Bulk heterojunction (BHJ) organic solar cells based on p-type polymers and n-type fullerene derivatives have attracted increasing attention due to their promising potential for providing low–cost solar electricity. In this paper, we will introduce our recent work on the development of new fullerene derivatives. Through Rh complex catalyzed coupling reactions and cycloaddition reactions, we attached several organic functional groups to the fullerene skeleton. It was found that the organic substituents had little impact on the fullerene energy levels. Instead, the organic substituents have huge impact on the other physical properties of the resulting fullerene derivatives, such as solubility, crystallinity, and electron mobility. We designed and synthesized a novel series of alkoxy substituted indene derivatives as solubilizing groups for fullerenes. Preliminary experimental results demonstrated that these 5 alkoxyindene modified C70 derivatives are superior to widely used PC71BM when blended with poly[N-heptadecanyl-2,7 carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'- benzothiadiazole)] (PCDTBT) in BHJ solar cells. The device series resistance decreased from 10 cm2 for the PC71BM based device to 4 cm2 for the 5-methoxyindene-C70 monoadduct based device. As a result, the device fill factor increased from 0.60 to 0.69, and the overall EQE-calibrated power conversion efficiency was enhanced from 5.6% to 6.2%.
Analysis of power supply possibilities through lithium batteries connected to the AC grid
Authors: R. Dufo López  , S. Sanz Ortega  , J.S. Artal Sevil  , M. Astaneh  , J. Lujano Rojas  , J.A. Domínguez  Navarro  , J.L. Bernal Agustín
Published: April 2018

In this paper we present a techno-economical analysis of grid-connected lithium batteries. A time-of-use (TOU) electricity tariff will be considered so that batteries can be charged during hours of low electricity price and discharged during hours of high electricity price. Four cases will be studied, depending if it is allowed or not to inject electricity to the AC grid during the discharge of the batteries and also depending if there is photovoltaic generator. Case 1: batteries discharge just to meet the load (no electricity injection to the grid); Case 2: Batteries discharge meet the load and also inject to the grid; Case 3: Photovoltaic generator + case 1; Case 4: Photovoltaic generator + case 2. In all the cases, the Net Present Cost (NPC) is calculated. All the cases are compared to the base case of supplying electricity without batteries. The Li-ion battery cost must be reduced at least 70% to be profitable in this applications. In that case, if selling electricity to the AC grid is allowed and the selling price is 70% of the price of the electricity, the battery system can be a good option, with or without PV generator.
A case study of floating offshore wind park in the Mediterranean
Authors: J. Milagro Serrano  , J.A. Domínguez-Navarro  , J.S. Artal-Sevil  , R. Dufo-López
Published: April 2018

This work presents a case study of floating offshore parks in the Mediterranean Sea. There are several constraints that determinate the location of the park: the availability of a sufficient wind resource, environmental laws, sea routes, the seabed depth (what will condition the whole project), the proximity of the necessary infrastructures and a social constraint. The Mediterranean seabed depth conditions the structure of the wind farm, which consists of the selection of the most adequate platform, the configuration of the mooring lines of those platforms, the type of wind turbine to install and their layout. The calculation of the power production is based on SIMAR data set, supplied by Puertos del Estado. A study of the wake effect produced by wind turbines based on the Jensen’s model has also been carried out. The power extraction system consists of three parts: a 33 kV line for the inter-array cables, an offshore substation located in the middle of the wind farm and a 220 kV line for the connection to shore. The conclusions obtained from this study are clear: this kind of projects are available in our country, and they are quite profitable if they are structured properly, though its profitability is lower than in other countries. In any case, there is still quite uncertainty concerning to that, a fact mainly motivated by the lack of a specific legislation in Spain.
Analysing Effect of Solar Photovoltaic Production on Load Curves and their Forecasting
Authors: B. Sinkovics  , B. Hartmann
Published: April 2018

Increasing share of intermittent renewable energy sources has generated several issues for power system operators. One aspect of these is the unpredictability of volatile production, affecting day-ahead load forecasting on system level, which is a major challenge for transmission system operators to solve. The literature widely discusses the short- and medium-horizon forecasting methods for weather dependent renewable energy sources, and proposals have also been raised to solve the issue. The aim of present paper is to estimate the effect of solar photovoltaic generation on the daily load curve of a national power system. To achieve this, current forecasting methods of transmission system operators are reviewed and evaluated. Then an own forecasting method is designed and implemented, based on historical load data from years where share of solar photovoltaics was neglectable. A learning algorithm is used for future predictions, using installed capacity and weather data. Finally, forecasted and actual load curves are compared, and effects of solar photovoltaic generation are estimated.
Investment risk analysis of electricity generation from vinasse biodigestion in the Brazilian Regulated Market
Authors: Luane Schiochet Pinto  , Daywes  Pinheiro Neto  , Elder Geraldo Domingues
Published: April 2018

This paper presents a methodology of investment risk analysis of the electricity generation by using biogas from biodigestion of sugarcane vinasse produced in sugarcane agroindustries. The methodology to be presented uses econometric models to generate synthetic time series of ethanol production, which is used to estimate the production of vinasse, biogas and electricity. The economic viability analysis will be done from the evaluation of the probability distribution functions of Net Present Value, Modified Internal Rate of Return and Discounted Payback, by considering that the electricity produced is commercialized in the Brazilian Regulated Contracting Environment. A case study is carried out using real data from a sugarcane plant located in the Midwest region of Brazil. The results indicate the economic viability of the project implementation.
Speed Estimation of Induction Motor at Low and Zero Speed using High Frequency Signal Injection for Rotor Slot Harmonics Detection
Authors: S. Damkhi  , M.S. Nait Said  , N. Nait Said
Published: April 2018

Rotor position estimation based on high frequency signal injection method represents the interesting way to provide the high performances of the AC drives sensorless controlled at low or near zero speed range. So, this method requires the existence of saliencies inside the IM particularly the presence of the slots where their design constitutes the main advantageous to exploit its effect for rotor speed monitoring. First, the present paper exposes a model of the induction machine including slotting effects which it can be exploited in order to extract the harmonic saliency created by rotor slotting. Second, the high frequency signal injection method is used in order to allow tracking the characteristic harmonic saliency due to rotor slotting from which the rotor position and speed may be estimated. A High frequency voltage signal injection creates a high frequency current modulated by the saliencies presented inside the machine. To extract information about rotor position, the resulting stator current treads to heterodyning process to eliminate the disturbance components and subsequently the rotor position may be extracted by a closed-loop observer. Simulation results are shown in order to verify the validity of the proposal and to confirm the effectiveness of estimation method at zero frequency.
Solar Induction Cooker
Authors: S. Karim
Published: April 2018

There is no available power grid in the rural areas in many countries in South America, Asia and Africa. st places, Fossil fuel or wood is used for cooking. Besides environmental issues, fossil fuel and wood from trees are being depleted at a fast rate. Solar power is available everywhere during day time in all countries. This solar induction cooker uses a solar panel, which gives a variable dc, to charge a battery. The dc from the battery is converted to a high frequency ac voltage by an inverter circuit. This inverter circuit supplies alternating current to a coil on a magnetic core where alternating flux is produced. This alternating flux produces in the magnetic core Eddy current and Hysteresis ‘losses’ inside the magnetic core. In this application, these losses will produce useful heat. A cooking pot placed on the magnetic core will be used for cooking.
Diagnostic accuracy of combined dipyridamole stress perfusion and delayed enhancement cardiovascular magnetic resonance imaging for detection of coronary artery disease
Authors: Chattranukulchai Pairoj , Tumkosit Monravee , Cholteesupachai Jiranut , Chaipromprasit Jarkarpun
Published: April 2018

Background: The diagnosis of coronary artery disease (CAD) is one of the most common clinical issues that face medical practitioners. Myocardial ischemia can be noninvasively assessed with cardiovascular magnetic resonance imaging (CMRI), which has become an emerging modality. Objective: Determine the accuracy of dipyridamole stress CMRI by using stress and rest perfusion combined with delayed enhancement imaging for detecting CAD. Methods: Thirty-nine patients (24 men, 15 women; mean age 64±11.4 years) who had experienced prior myocardial infarction or had suspected CAD were enrolled. Dipyridamole stress CMRI with subsequent coronary angiography was performed within a mean time interval of 16 days (range: 1-30 days). The dipyridamole stress CMR protocol included stress and rest perfusion followed by delayed enhancement imaging. Per-vessel analysis was done according to 17-segment model recommendation by the American Heart Association. Results: Coronary angiography depicted significant coronary artery stenosis (>70% stenosis of major epicardial artery) in 26 patients (55 coronary arteries). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the combined stress and rest perfusion with delayed enhancement imaging for detection of significant coronary artery stenosis were 76-96%, 79-96%, 87-93%, 83-96%, and 85-95%, in left anterior descending, left circumflex, and right coronary arteries, respectively. Without delayed enhancement imaging, stress and rest perfusion produced slightly lower sensitivity (69-92%), specificity (73- 96%), positive predictive value (79-93%), negative predictive value (80-92%), and accuracy (79-92%). Conclusion: Dipyridamole stress CMRI combined with delayed enhancement imaging yielded high diagnostic accuracy for the detection of coronary artery disease. This modality allows the clinical application for detection of CAD in selected group of patients.
Magnetic resonance imaging findings of hepatocellular carcinoma: typical and atypical findings
Authors: Vajragupta Laddawan , Kittisatra Khanitha , Sasiwimonphan Kewalee
Published: April 2018

Background: Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. Magnetic resonance imaging has been widely used for detection and characterization of HCC. Objective: Describe MRI findings of HCC and to define the typical and atypical appearances of HCC on magnetic resonance images. Methods: We retrospectively reviewed MRI findings of 100 HCC in 78 patients. Diagnosis was confirmed by angiography, pathology or follow up imaging. The signal intensity, size, margins, enhancement pattern, and other features were evaluated. Imaging findings between small HCC (< 2 cm) and large HCC (>2 cm) were compared. Results: The most common signal intensity of HCC on unenhanced T1- and T2-weighted images was hypointense on T1-weighted images and hyperintense on T2-weighted images (65%). Most HCC (91%) were hyperintense on T2-weighted images. Isointensity on T2-weighted images were found in 9% of HCC. The typical enhancement pattern of HCC was enhancement on the arterial phase and washout on the portovenous phase (84%). Atypical enhancement pattern of HCC were enhancement on the portovenous phase in 5%, rim enhancement on the arterial phase or portovenous phase were demonstrated in 2%. Hyperintensity of the tumor on delayed phase was found in 19%. There was no statistically significant difference in signal intensity, enhancement, and washout pattern between small and large HCC. Fatty metamorphosis, mosaic pattern, necrosis, capsule and vascular involvement were found in 18%, 42%, 5%, 62%, and 6%, respectively. Mosaic pattern, necrosis, capsule, and vascular involvement were observed more frequently in large HCC. Conclusion: The typical appearance of HCC was hypointense on T1-weighted, hyperintense on T2-weighted images, arterial enhancement and portovenous washout. Atypical appearances of HCC were rim enhancement on the arterial phase or portovenous phase and persistent enhancement on the delayed phase
Dosimetry of conformal dynamic arc radiotherapy and intensity modulated radiotherapy in unresectable cholangiocarcinoma
Authors: Peerawong Thanarpan , Khorprasert Chonlakiet , Suriyapee Sivalee , Sanghangthum Taweap , Ayuthaya Isra Israngkul Na , Shotelersuk Kanjana
Published: April 2018

Background: Radiotherapy in cholangiocrcinoma has to overcome organ tolerance of the upper abdomen. Hi-technology radiotherapy may improve conformity and reduce dose to those organ. Objective: Quantitatively compare the dosimetry of conformal dynamic arc radiotherapy (CD-arcRT) and intensity modulated radiotherapy (IMRT) in unresectable cholangiocarcinoma. Material and methods: Eleven cases of unresectable cholangiocarcinoma were re-planned with IMRT and CDarcRT at King Chulalongkhorn Memorial Hospital between 20 September 2004 and 31 December 2005. Both the planning techniques were evaluated using the dose volume histogram of the planning target volume and organ at risk. The conformation number and dose to critical normal structures were used to determine the techniques. Results: IMRT technique was significantly conformed to the planning target volume than CD-arcRT in term of conformation number. For critical structure, IMRT significantly reduced the radiation dose to liver in terms of mean liver dose, V30Gy and V20Gy of the right kidney. Conclusion: The advantage of IMRT was more conformity and reduced dose to critical structure compared with CD-arcRT, but there was no difference between these techniques in terms of V20Gy of left kidney and maximum dose to the spinal cord.
An evaluation of 2.0 McFarland Etest method for detection of heterogeneous vancomycin-intermediate Staphylococcus aureus
Authors: Pongkumpai Montri , Trakulsomboon Suwanna , Suankratay Chusana
Published: April 2018

Background: Staphylococcus aureus with reduced susceptibility to vancomycin or heterogeneous vancomycinintermediate S. aureus (hVISA) have become increasingly reported from various parts of the world. hVISA cannot be detected by routine test for minimal inhibitory concentration (MIC) for vancomycin. The gold standard method for detection, population analysis profiles (PAP) method, is complicated, time-consuming, expensive, and needs well-trained microbiologists. Objective: Evaluate of 2.0 McFarland Etest method, in comparison with the PAP method, for detection of hVISA in clinical specimens. Methods: All methicillin-resistant S. aureus strains from clinical specimens isolated from consecutive patients attended at King Chulalongkorn Memorial Hospital and Siriraj Hospital, Bangkok between 2006 and 2007 were studied. 1 hundred nineteen specimens were obtained. The PAP method detected six hVISA strains 5 from blood and from cultures) from four patients at King Chulalongkorn Memorial Hospital, accounting for a prevalence of 6.35%. The MIC determined by agar dilution method was in the range of 2-3 μg/mL. Results: 2.0 McFarland Etest method detected no false positive and five false negatives (42%), and gave a sensitivity and a specificity of 16.7% and 100%, respectively. The one-point population analysis screening method detected two false positives and 1 false negative, and gave a sensitivity of 83.3% and a specificity and 98.2%. Conclusion: The 2.0 McFarland Etest method had a very good specificity but a poor sensitivity for detecting hVISA. It may be used as an alternative method to confirm detection of hVISA.
Incidence of acquired lacrimal drainage system obstruction in epiphoric patients in Thailand
Authors: Tirakunwichcha Suppapong , Rengwanidchakul Ehwika , Asawaphureekorn Somkiat , Tengtrisorn Supaporn , Juangphanich Khanchai , Suramethakul Pitipong , Pornpanich Kanokrat
Published: April 2018

Background: There were few reports regarding the incidence of the acquired nasolacrimal duct obstruction, and the incidence in different geography or countries might be alike. Since the nasolacrimal drainage system obstruction is a common problem in Thailand, knowledge of the incidence may disclose the burden of the disease that has never been reported. Objectives: Evaluate the incidence of acquired lacrimal drainage system obstruction (ALDO) in Thailand. Methods: This study was conducted in multi-centers. It was based on prospective and descriptive design. All patients with epiphoric symptoms visiting the outpatient departments of five tertiary eyecare centers were recruited between 2004 and 2007. Features of epiphoric symptoms and medical history were recorded, and complete ophthalmic examinations were performed. Results: Epiphoric patients were enrolled from all medical centers with 245 eligible patients, female:male ratio was 4.2:1. Ninety-nine patients (40%) had duration of epiphoric symptoms between one-five years. ALDO was found in 111 patients (45%) with female preponderance (6.9:1). Seventy-one patients (64%) had pre-sac obstruction and 40 patients (36%) had post-sac obstruction. Among other causes of epiphora, dry eye was the most common. Conclusion: The most common cause of epiphora was ALDO. The four-year incidence rate of ALDO among epiphoric patients was 45%.
Comparative study of effective-site target controlled infusion with standard bolus induction of propofol for laryngeal mask airway insertion
Authors: Sintavanuruk Krairerk , Pongruekdee Sukanya , Thaharavanich Russana , Laosuwan Surajak , Charuluxananan Somrat
Published: April 2018

Several studies demonstrated induction of anesthesia with different plasma target-controlled infusion (TCI) of propofol for LMA insertion. However, there has been no study to compare the standard bolus propofol induction with the effective site TCI for LMA insertion. Objective: Compare the efficacy of induction of anesthesia with propofol for LMA insertion between the effective-site TCI, using 6 μg/mL, and the standard bolus propofol dose of 2.5 mg/kg in elective surgical patients. Methods: A randomized, prospective, single-blinded, clinical study was used for this study. Seventy-eight unpremedicated patients, American Society of Anesthesiologists (ASA) physical status I and II undergoing elective surgical procedure were randomly allocated between two groups. Group 1 received the standard bolus propofol dose of 2.5 mg/kg. Group 2 received effective site TCI (Schnider model) dose of 6 μg/mL for LMA insertion. The hemodynamics and anesthetic depth (Bispectral index score) were monitored and recorded during and immediately after LMA insertion. The number of insertion attempted, insertion quality score, induction time, and propofol doses used were recorded and compared between groups. Results: The success rate of first insertion attempt was equal in both groups (92.3%). There was no significant hemodynamic response difference between the groups during pre-induction, induction, insertion, and post insertion period. The BIS score was significantly lower during post insertion period in group 1 (51.4+11.0) than group 2 (58.4+3.2) (p=0.013). The propofol doses in group 2 were significantly lower than in group 1 (110.6+14.8 vs. 153.5+21.5) (p <0.001). Patients in group 2 required significantly more induction time than group 1 (146.9+42.3 vs. 103.4+33.6 (p <0.001). Conclusion: Propofol induction with TCI provided equal success rate as compared with standard bolus propofol induction for LMA insertion and insertion quality score. TCI significantly lowered the propofol consumption when compared with the standard 2.5 mg/kg propofol dose.
Thai national guidelines for the prevention of motherto- child transmission of HIV: March 2010
Authors: Phanuphak Nittaya , Lolekha Rangsima , Chokephaibulkit Kulkanya , Voramongkol Nipunporn , Boonsuk Sarawut , Limtrakul Aram , Limpanyalert Piyawan , Chasombat Sanchai , Thanprasertsuk Sombat , Leechawengwong Manoon
Published: April 2018

Thailand has been one of the leading developing countries to implement a national program to prevent mother-to-child transmission (MTCT) of HIV. Although the recent transmission rate has been low, the goal is to eliminate MTCT altogether. The Thai National HIV Guidelines Working Group issued treatment guidelines to prevent MTCT in Thailand in March 2010. These guidelines will be implemented nationwide within a year. The most important aspects of these new guidelines are as follows: Treatment in HIV-infected pregnant women who have not been on antiretroviral treatment prior to pregnancy. Antepartum treatment is recommended for all pregnant women regardless of CD4 count with highly active antiretroviral therapy (HAART) containing zidovudine (AZT) + lamivudine (3TC) + lopinavir/ritonavir (LPV/r). Treatment should be started immediately irrespective of gestational age in women with CD4 count <350 cells/ mm3, and as early as 14 weeks of gestation in those with CD4 count >350 cells/mm3. After delivery, women with baseline CD4 count <350 cells/mm3 are referred for long-term care and HAART according to the National Adult HIV Treatment and Care Guidelines 2010. Women with CD4 count >350 cells/mm3 do not need HAART and can stop all drugs after delivery. The treatment in infants includes AZT syrup for four weeks and exclusive formula feeding. Treatment in HIV-infected pregnant women who conceive while on HAART. Women who are stable on HAART should continue the treatment during the whole period of pregnancy. Those who are taking efavirenz (EFV) and present during the first trimester should have EFV switched to another drug. Whenever possible, AZT should be used during pregnancy. Treatment in infants is similar to the above scenario. Treatment in women who present in labor without antenatal care. Single-dose nevirapine (SD-NVP) 200 mg must be given immediately along with oral AZT 300 mg every three hours until delivery, or oral AZT 600 mg given as a single dose. The tail therapy of AZT + 3TC + LPV/r for four weeks should be given unless these women have a CD4 count of <350 cells/mm3 and therefore require life-long HAART. SD-NVP should not be given if the women are to deliver within two hours. The infants in this situation should receive AZT + 3TC + NVP for four weeks. Treatment during delivery and mode of delivery. During labor, oral AZT 300 mg every three hours or oral AZT 600 mg given as a single dose is recommended regardless of antepartum antiretroviral (ARV) regimen or the woman’s history of AZT resistance. Elective caesarean section is suggested in women who did not receive HAART (including those without antenatal care), received HAART for less than four weeks prior to delivery, had poor adherence, or had incomplete viral suppression at 36 weeks of gestation.
Comparison between Pseudomonas aeruginosa siderophores and desferrioxamine for iron acquisition from ferritin
Authors: Srifuengfung Somporn , Assanasen Susan , Tuntawiroon Malulee , Meejanpetch Sumonrat
Published: April 2018

Background: Siderophore is an iron chelator produced by microorganism. Pseudomonas aeruginosa produces two siderophores (pyoverdin and pyochelin). Desferrioxamine is a siderophore used in thalassemia patients to treat an iron overload of vital organs. Objective: Compare the ability of pyoverdin, pyochelin, and desferrioxamine for iron mobilization from ferritin. Materials and Methods: In vitro experiment, the ability of P. aeruginosa siderophores and desferrioxamine for iron mobilization from ferritin was compared by using a dialysis membrane assay at pH values of 7.4 and 6.0. Stimulation of P. aeruginosa PAO1 growth by all siderophores was studied in glucose minimum medium. Results: All three compounds were capable of iron mobilization at both pHs. At pH 6.0, the most effectiveness compound was desferrioxamine (31.6%), followed by pyoverdin (21.5%) and pyochelin (13.7%) compared on weight basis, each at 10 μg/mL. At equimolar concentration, their activities were desferrioxamine (38.5±1.2%), followed by pyoverdin (32.0±4.8%) and pyochelin (26.7±1.9%), respectively. Conclusion: The most effective compound in iron mobilization from ferritin was desferrioxamine, followed by pyoverdin and pyochelin respectively.
Eye diseases associated with obstructive sleep apnea syndrome in an Asian population
Authors: Hirunwiwatkul Parima , Puangsricharern Vilavun , Sothornwit Nisa , Pongpun Prin Rojana , Sawatdiwithayayong Jeerawat , Hirunwiwatkul Prakobkiat
Published: April 2018

Background: Sleep apnea syndrome is one of the leading causes of excessive daytime sleepiness. There is no literature exploring the prevalence of sleep-associated disorders in the eye of Asians with obstructive sleep apnea syndrome (OSA). Objective: Study the prevalence of eye abnormalities in Asian patients with OSA. Material and method: Asian patients with definite OSA diagnosis via the polysomnography were recruited into the study. Complete eye examination and special investigations were performed to define eye diseases: floppy eyelids, dry eyes, keratoconus, Fuchs’ endothelial dystrophy, recurrent corneal erosions, open-angle glaucoma, ophthalmoplegia, papilledema and optic neuropathy. Results: One-hundred Asian OSA patients were examined. We found that floppy eyelids, dry eyes, and normal tension glaucoma were more prevalent compared to the normal population. Abnormal endothelial change and papilledema were detected. Optic neuropathy and ophthalmoplegia were not found in this study, although some patients did have subnormal contrast sensitivity. Conclusion: There is a higher prevalence of floppy eyelids, dry eyes, and glaucoma in OSA patients. Complete eye examination is recommended in OSA patients to detect early eye abnormalities.
Elevated urinary total sialic acid and increased oxidative stress in patients with bladder cancer
Authors: Opanuraks Julin , Boonla Chanchai , Saelim Chawalit , Kittikowit Wipawee , Sumpatanukul Pichet , Honglertsakul Chavalit , Tosukhowong Piyaratana
Published: April 2018

Background: Increased production and release of sialic acid have been reported in many malignant conditions including bladder cancer. 8-hydroxydeoxyguanosine (8-OHdG) and malondialdehyde (MDA) have been widely used as oxidative stress biomarkers. Objective: Determine urinary levels of total sialic acid (TSA), 8-OHdG, and MDA in patients with urinary bladder cancer, and evaluate their clinical relevance. Patients and methods: Forty-five patients with histologically proven bladder cancer and 41 healthy subjects were recruited for the study. Morning urine samples were collected from all participants for measurements of TSA, 8-OHdG and MDA using thiobarbituric assay, competitive ELISA and spectrophotometry methods, respectively. Histological examination was performed for all patients. Results: Bladder cancer patients excreted urinary TSA, 8-OHdG, and MDA significantly higher than healthy controls. Based on receiver operating characteristic curve analysis, urinary TSA had adequate diagnostic potential to distinguish patients from healthy populations, and its cutoff value was chosen at 95.26 μg/g creatinine. Sensitivity, specificity, and accuracy of urinary TSA determination were 75.6%, 75.6%, and 75.6%, respectively. Both in patient and healthy groups, urinary TSA was linearly correlated with urinary 8-OHdG. Patients with highseverity grade (n=27) excreted urinary TSA significantly greater than those with low-severity grade (n=18). Conclusion: Urinary TSA, 8-OHdG, and MDA increased in patients with bladder cancer. The elevated urinary TSA was associated with enhanced oxidative stress. In addition, urinary TSA increased with progressiveness of the tumor.