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The field of flat optics that uses nanostructured, so-called metasurfaces, has seen remarkable progress over the last decade. Chalcogenide phase-change materials (PCMs) offer a promising platform for realizing reconfigurable metasurfaces, as their optical properties can be reversibly tuned. Yet, demonstrations of phase-change metalenses to date have employed material compositions such as Ge2Sb2Te5, which show high absorption in the visible to near-IR wavelengths particularly in their crystalline state, limiting the applicability. Here, by using a low-loss PCM Sb2Se3, for the first time, active polarization-insensitive phase-change metalenses at near-IR wavelengths with comparable efficiencies in both material states are shown. An active metalens with a tunable focusing intensity of 95% and a focusing efficiency of 23% is demonstrated. A varifocal metalens is then demonstrated with a tunable focal length from 41 to 123 µm with comparable focusing efficiency (5.7% and 3%). The ultralow-loss nature of the material introduces exciting new possibilities for optical communications, multi-depth imaging, beam steering, optical routing, and holography.

In the exploitation of nanozymes possessing intrinsic enzyme-like activities for cancer therapy, minor focus has been devoted to plasmonic nanostructures with localized surface plasmon resonance (LSPR)-driven properties. Here, we report the application of unique peroxidase-mimicking plasmonic photo-nanozymes coupling tumor-microenvironment-responsive reactive oxygen species generation with photothermal effect for effective combinatorial therapy. The well-defined anisotropic photo-nanozyme is synthesized by selectively depositing Pd nanoparticles on the tips of gold nanobypyramids. Intrinsic peroxidase-like properties with 1.5-fold-activity enhancement under photoexcitation are ascribed to a Pd-induced hot electrons/holes separation with efficient H2O2 decomposition. The LSPR-induced photocatalytic/photothermal combinatorial effects are remarkably enhanced upon H2O2 addition, critically suppressing the cell survival rate under near-infrared light. An effective decomposition of cell-signaling H2O2 additionally reveals prominent expression hindrance of vascular endothelial growth factor and hypoxia-inducible factor 1α. Our seminal findings uncover an interrelation between LSPR-induced phenomena and biomimetic fingerprints, valuable to overcome the shortcomings of conventional photodynamic therapy.

Wavelength and polarization are two fundamental properties of light within which information can be encoded and (de)multiplexed. While wavelength-selective systems have widely proliferated, polarization-addressable active photonics has not seen notable progress, primarily because tunable and polarization-selective nanostructures have been elusive. Here, we introduce hybridized-active-dielectric (HAD) nanowires to achieve polarization-selective tunability. We then demonstrate the ability to use polarization as a parameter to selectively modulate the conductance of individual nanowires within a multi-nanowire system. By using polarization as the tunable vector, we show matrix-vector multiplication in a nanowire device configuration. While our HAD nanowires use phase-change materials as the active material, this concept is readily generalized to other active materials hybridized with dielectrics and thus has the potential in a broad range of applications from photonic memories and routing to polarization-multiplexed computing.

In this work, we propose a novel architecture for building a robust integrated photonic neuromorphic accelerator based on a crossbar array design. Our architecture is based on an asymmetric multimode Y-coupler. A Y-coupler has the inherent benefit of high fabrication tolerance and broad optical bandwidth. From simulations, we show that our proposed Y-coupler has high coupling efficiency. Using modal decomposition analysis of our coupler, we numerically estimate the energy efficiency performance of a large-scale photonic network and show a 10% improvement in energy efficiency for large-scale photonic networks with high fabrication tolerance and broadband application and a small footprint.

In this study, we propose reconfigurable metasurfaces based on a low-loss chalcogenide phase-change material, antimony triselenide (Sb2Se3). The developed metasurfaces exhibit tunable focusing properties along with transformation of the Sb2Se3 between amorphous and crystalline states.

Ever-increasing processing and storage requirements steer us towards co-integration of electronics and photonics. Here, we demonstrate waveguide-integrated plasmonic memory and computing elements by employing phase-change materials with reconfigurable properties and dual electro-optic functionality.

While plasmonic designs have dominated recent trends in structural color, schemes using localized surface plasmon resonances and surface plasmon polaritons that simultaneously achieve high color vibrancy at ultrahigh resolution have been elusive because of tradeoffs between size and performance. Herein we demonstrate vibrant and size-invariant transmissive type multicolor pixels composed of hybrid TiOx-Ag core-shell nanowires based on reduced scattering at their electric dipolar Mie resonances. This principle permits the hybrid nanoresonator to achieve the widest color gamut (~74% sRGB area coverage), linear color mixing, and the highest reported single color dots-per-inch (58,000~141,000) in transmission mode. Exploiting such features, we further show that an assembly of distinct nanoresonators can constitute a multicolor pixel for use in multispectral imaging, with a size that is ~10-folds below the Nyquist limit using a typical high NA objective lens., Tradeoffs between size and performance have limited plasmonic structural color vibrancy at high resolution. Here the authors present a nanophotonic resonant metal-coated nanowire capable of being used as a size invariant, vibrant multicolor pixel.

In this paper, an accurate high-frequency modeling methodology for a permanent magnet synchronous motor (PMSM) in a vehicular electrical braking system is presented, which is suitable for analyzing various electromagnetic interference problems caused by a motor drive system. The proposed modeling approach is established according to the vector fitting technique and based on the S-parameter measurements of the PMSM. The equivalent circuit model of the PMSM converted from a measured S-parameter matrix can better describe the impedance characteristics of the three-phase PMSM under study compared to the existing equivalent circuit models because the imbalances inside the motor are taken into account in the proposed modeling process. The proposed PMSM model exhibits high accuracy in the range from 100 kHz to 120 MHz in comparison with the common-mode and differential-mode characteristics of the PMSM, which are measured using the conventional setups.

This paper presents a method for the reduction of mode conversion from differential-mode (DM) noise to common-mode (CM) noise in an unbalanced EMI filter. The unbalanced nature in the EMI filter is a result of not incorporating all the required filter components due to space and cost constraints or due to the parasitic impedances of a printed circuit board (PCB). It is demonstrated that the reduction of mode conversion from DM noise to CM noise can be achieved by modifying the current path on the ground (GND) layer of the PCB of the unbalanced EMI filter. The currents on the GND layer are guided to take a longer route by introducing a "cutout" to the ground plane in the PCB, which increases the impedance of the current path on the GND layer. This approach does not require additional components to the EMI filter for the reduction of CM noise due to the mode conversion. Simulations show that the cutout decreases the CM noise converted from the DM noise by at least 4 dB in the AM radio frequency band (530 kHz – 1.8 MHz).

In this paper, a model for a prediction of conducted emission from vehicular PMSM-drive braking system is presented. The proposed model is based on the high-frequency circuit model combined with EM simulation. The parameter for high-frequency circuit modeling is derived from the measurement as well as 3D EM simulation based on FEM. To establish meaningful high-frequency parameters, the lumped parameters concerning the three-phase motor coil, motor busbar, heatsink, LISN, harness wire, meshed strap wire, and the passive-EMI filters including parasitics are either electromagnetically simulated or directly measured through an impedance analyzer. The distributed parameters of the PCB’s, connector, and motor housing are calculated via the 3D EM simulation. Eventually, the presented high-frequency parameters were integrated with PWM inverter circuit for the system-level analysis, and the model was verified through the correlation between the measurement and simulation with the EMI filters installed in the system. Moreover, the EMI characteristics with/without particular noise propagation path were analyzed in the model. The calculated conducted emission of the proposed model showed a very good agreement with the experimental data, which proves the validness of the proposed model.

Extraordinary light–matter interaction on the surface of metallic nanostructures can excite surface plasmons (SPs), followed by generation of charge carriers with high energy, that is, “hot electrons and holes”, via nonradiative decay. Such plasmonic hot carriers are potentially useful for photocatalysis, electrocatalysis, photovoltaics, optoelectronics, and theragnosis since hot carrier transfer to the desired substrate can accelerate specific redox reactions or facilitate electrical benefits on devices. In this regard, there is a growing interest in the detection and visualization of hot carriers at the location where plasmonic hot carriers are practically generated and transferred by means of conventional or newly developed procedures, as summarized in Table 1 of the main paper. Although direct imaging of plasmonic hot carriers or pathways are still challenging due to ultrafast dynamics of plasmonic hot carriers, state-of-the-art microscopic approaches have successfully demonstrated the mapping of the ...

In electric vehicles, the pulse width modulation scheme is widely used in three-phase motor drive systems for its high performance. However, the fast switching of semiconductor devices may induce excessively high dv/dt and di/dt, which can cause electromagnetic interference (EMI) issues, making it difficult to satisfy electromagnetic compatibility standards. In this paper, the current conducted emission test for a three-phase motor drive system is performed based on CISPR 25 component-level testing setup for AM radio frequency band, which is from 530 kHz to 1.8 MHz. Under these conditions, common-mode (CM) noise generation mechanisms of the motor drive system are identified through measurements. It is found that the dominant mechanism is the mode conversion from differential mode (DM) switching current of the three-phase PWM inverter to CM current through the cable harness due to the imbalances in the PCB structure and EMI filter network which are at the dc input side of the three-phase inverter. Based on this finding, ground (GND) bridges are added between the digital signal and power GND nets to reduce the CM noise. The GND bridge effect on the reduction of CM noise in AM band is experimentally verified and further studied using circuit simulations.

The development of solar energy conversion in the production of fuels, water splitting and water purification systems, has become an important sidestep for traditional fossil energy. Herein we have investigated the coupling effect of a Photo-Fenton system on a conventional photocatalytic reaction with a novel Fe-doped C 3 N 4 /WO 3 hybrid structure. The decomposition of p -nitrophenol was selected as a model reaction in the context of the degradation of organic pollutants. Heterojunction nanocomposites consisting of g-C 3 N 4 nanosheets and WO 3 nanoparticles were shown to facilitate the separation of photo-induced electron and hole pairs. The photocatalytic activity was further maximized as a result of a synergism of the ‘Photo-Fenton cycle’ with Fe(II) or Fe(III)-doping in the presence of H 2 O 2 to generate additional hydroxyl radicals. As a result, after 4 h under visible light the degradation of p -nitrophenol could be remarkably enhanced from 10 to 90% compared to the g-C 3 N 4 reference. To the best of our knowledge, this is the first time such a striking increase is reported with a Photo-Fenton system applied in the present photocatalytic system. The significance of the presence of hydroxyl radicals in the photo-Fenton performance of Fe-doped C 3 N 4 /WO 3 was assessed by scavenger and fluorescence tests. Additional light was shed into the reaction mechanism via spin trapping enabled by in-situ electron paramagnetic resonance.

This article proposes an efficient model to reduce the conducted emission in a motor-driven autonomous emergency braking system. Many X/Y decoupling capacitors have been employed in this system to repress the switching noises, which is a very important consideration for the reliability/safety of the system. However, the locations of the decoupling capacitors, have basically been determined, thus, far by trial and error. The proposed model, in this article, consists of a circuit of the permanent magnet synchronous motor-driven braking system which is combined with electromagnetic simulation models, and the whole models are integrated into a SPICE simulator. The effect of decoupling capacitors was analyzed, and a binary particle swarm optimization algorithm was applied to determine the most effective decoupling capacitor locations to minimize the number of capacitors in the system. An automation program with the optimization algorithm was developed using Python language. The optimized results showed the number of decoupling capacitors could be reduced from 36 to 28 in the specific motor-driven autonomous emergency braking system while still satisfying the electromagnetic interference specification of automaker requirements, which validates the effectiveness of the proposed methodology.

In this paper, a modeling method for predicting the conducted emission with a current probe method is presented for a motor-drive braking system. The proposed model considers the motor driving circuit components and the measurement environment. The models of motor driving circuit component include PWM inverter circuits, 3-phase motor, PCB, heatsink, bus bars, and motor casing. The models of measurement environment involve the current probe, test table including ground plane, harness cable, and LISN. To reflect the accurate path of common and differential mode current of the motor drive system, co-simulation is proposed with the equivalent circuit and SPICE model. Co-simulation is eventually conducted by using EMC Studio of EMCoS Ltd. for the calculation of electromagnetic coupling around the circuit, and the high-frequency parameters of the motor driving circuit are calculated through ANSYS Inc.'s Q3D. For the model validation, the measurement and simulation results are compared, and the results of the conducted emission of those agree well in the range of 100 kHz up to 108 MHz.

In the EV/HEV motor driving system, one of the most important elements that should be taken into account would be a battery that drives the whole system, because the rest of the circuit elements except battery have been relatively well established in the power electronics area. Because of the high frequency power harmonic noises inherent in the circuit, exact voltage fluctuation analysis of the driving circuit at the design stage has been emphasized quite a lot so far. This paper describes the analysis of motor driving circuit with novel battery model employed: as a result, the fluctuated battery voltage for a given DOD (Depth of Discharge) could be calculated. A filter design procedure that takes into consideration of the battery characteristics is also described for a fixed DOD. The effectiveness of the designed filter was confirmed by simulation, which was performed by using MATLAB, Ansys' Simplorer, and Agilent Technology's ADS (Advanced Design System). EV (Electric Vehicle) or HEV (Hybrid-Electric Vehicle) basically employs power electronic circuit to charge battery as well as to drive a motor, and the high voltage in the circuit, typically in the range of hundreds volts, needs to be chopped to control the driving circuits, and as a result it is inevitable to produce high frequency harmonic voltage/ current components inside. Therefore one of the most important things the HEV motor circuit designer needs to consider is the prediction of the electromagnetic compatibility of the driving circuit at the design stage. This is crucial to avoid unnecessary trial and errors after fabrication of the whole driving circuit only to find that the circuit needs to be revised to satisfy EMC standards such as IEC/CISPR and ISO. Therefore, precise analysis of the motor driving circuit is mandatory in the EV/HEV development process at the design stage. The main elements of power electronic circuit in the HEV are such as a high voltage battery, IGBT (Insulated Gate Bipolar Transistor) inverter to control motor through PWM (Pulse Width Modulation) algorithm, BLDC (Brushless DC) motor, and so on. Since the other elements except the battery have been common in the classical driving circuit simulation, an emphasis is put on the battery circuit modeling, which enables to simulate the driving circuit at various DOD levels. For this purpose, battery circuit model includes not only a simple DC model in time domain, but also complex R-C elements in frequency domain, coming from charge transfer resistance and double layer capacitors in the battery. Since the R and C in the battery model depend on the DOD level of the battery, one needs to take into consideration the frequency-dependent battery impedance as well as the load condition to design the filters in the motor driving circuit. (1)(2) This paper is organized as follows. In the next chapter, battery model which is used in the analysis of motor driving system is introduced. In chapter 3 all the circuit elements, such as battery, inverter, and filters, are integrated to form the whole circuit, and brief filter design procedure is described. Chapter 4 demonstrates the simulated results of the voltage fluctuations and the conducted noise, and the effectiveness of the filter is also shown. Finally, this paper ends with a conclusion and further works in the last section.

This paper presents an equivalent circuit model of a LIPB (Li-Ion Polymer battery) for Hybrid Electric Vehicles (HEVs). The proposed equivalent circuit can be used to predict the charging/discharging characteristics in time domain as well as the impedance characteristic analysis in frequency domain. Based on these features, a one-cell model is established as a function of Depth of Discharge (DoD), and a 48-cell model for a battery pack was also established. It was confirmed by experiment that the proposed model predict the discharging and impedance (AC) characteristics quite accurately at different constant current levels. To check the usefulness of the proposed circuit, the model was used to simulate a motor driving circuit with an Insulated Gate Bipolar Transistor (IGBT) inverter and Brushless DC (BLDC) motor, and it is confirmed that the model can calculate the battery voltage fluctuation in time domain at different DoDs.

Poly(3,4-ethylenedioxythiophene) (PEDOT) is formed inside a metal–organic framework (MOF). MOF removal leads to sub-millimetre structures of the nanostructured conducting polymer., Reactions inside the pores of metal–organic frameworks (MOFs) offer potential for controlling polymer structures with regularity to sub-nanometre scales. We report a wet-chemistry route to poly-3,4-ethylenedioxythiophene (PEDOT)–MOF composites. After a two-step removal of the MOF template we obtain unique and stable macroscale structures of this conductive polymer with some nanoscale regularity.

In this paper, we propose a design method that the crosstalk of probe connector pins satisfy the limitation of -30 dB. The parameters(inductance and capacitance) were extracted in the grid-structured probe connector pin system, and it is shown that the new parameters are easily calculated with increasing ground pin numbers using the previously calculated parameters. In addition, the crosstalk reduction algorithm by employing more grounds around the signal pin has been suggested, and it is confirmed that the suggested method is quite effective especially for the reduction of inductive couplings. Finally, we suggested the correlation between the pitch and the length of the pins to satisfy the crosstalk limitation of -30 dB with the given number of ground pins, which will be quite useful when design a probe connector pin system.

In order to present that the electromagnetic compatibility standards following the frequency goes up which is based automotive electronics, in this paper, a hybrid/electric vehicle battery which reflects the frequency of the equivalent circuit model is introduced. By using this circuit modeling, the impedance characteristics can be analysed and an analyze of battery one cell is finished. Using this model, each different from the discharging situation, the discharge characteristic curve could be led. Basic theoretical approaches and measuring results through MATLAB and experimental validation of the EIS measurement equipment was used.

This paper proposes a novel electrical characterization approach for a high-performance package system using an improved Partial Element Equivalent Circuit (PEEC). As the effect of interconnects becomes a pivotal factor for the performance of high-speed electronic systems, there is a great demand for an accurate equivalent model for interconnects. In particular, an equivalent model of interconnects is established in this paper for the Fine-Pitch Ball Grid Array (FBGA) package using the improved PEEC method. Based on the equivalent model, electrical characteristics are analyzed; furthermore, these are verified through the measurement results of a Vector Network Analyzer (VNA).

This paper analyzes EM(Electromagnetic) characteristic in the high voltage connector for the hybrid electric vehicle. The connector bridges the electrical components and helps transferring electrical power and signal through it. The necessity of the high voltage and current connector development is emphasized because the hybrid electric vehicle recently uses the high voltage and current more than 500V and 80A. So far there has not been international EMC (Electromagnetic Compatibility) standards to limit the RE(Radiation Emission) from the connector for the hybrid electric vehicle. In this paper we analyzed EM characteristic of the 288V, 65A connector to check if the RE from the high voltage connector could be within the RE limit standard of vehicle. Three-dimensional modeling and simulation was conducted by using MWS(Microwave Studio) of the CST corporation, and the result was compared with the measured RE data, which showed good coincidence each other.

The conventional vertical probe has the thin and long signal path that makes transfer characteristic of probe worse because of the S-shaped structure. So we propose the new vertical probe structure that has branch springs in the S-shaped probe. It makes closed loop when the probe mechanically connects to the electrode on a wafer. We fabricated the proposed vertical probe and measured the transfer characteristic and mechanical properties. Compared to the conventional S-shaped vertical probe, the proposed probe has the overdrive that is 1.2 times larger and the contact force that is 2.5 times larger. And we got the improved transfer characteristic by 1.4 dB in GHz. Also we developed the simulation model of the probe card by using full-wave simulator and the simulation result is correlated with measurement one. As a result of this simulation model, the cantilever probe and PCB have the worst transfer characteristic in the probe card.

In this paper, we propose a new EBG structure that the two unit cells are connected by the bridge line in signal transmission plane. The SSN of the power plane is reduced effectively by via holes and bridge lines connecting the unit cells. The superior signal transfer characteristic is shown between the signal lines in the signal transmission plane. The proposed EBG structure contains 1.2 GHz cut-off frequency and less than －30 dB suppression in the 8.3 GHz broad bandwidth. In addition, To improve the SI(Signal Integrity) in signal transmission plane keeping the same bandstop frequency range, the optimized location of the reference plane is proposed.

The Homogeneous Charge Compression Ignition (HCCI) engine has attracted much interest because it can simultaneously achieve high efficiency and low emissions. However, the ignition timing is difficult to control because this engine has no physical ignition mechanism. In addition, combustion proceeds very rapidly because the premixed mixture ignites simultaneously at multiple locations in the cylinder, making it difficult to increase the operating load. In this study, an HCCI engine was operated using blended test fuels comprised of dimethyl ether (DME) and methane, each of which have different ignition characteristics. The effects of mixing ratios and absolute quantities of the two types of fuel on the ignition timing and rapidity of combustion were investigated. Cool flame reaction behavior, which significantly influences the ignition, was also analyzed in detail on the basis of in-cylinder spectroscopic measurements. The experimental results revealed that within the range of the experimental conditions used in this study, the quantity of DME supplied substantially influenced the ignition timing, whereas there was little observed effect from the quantity of methane supplied. Spectroscopic measurements of the behavior of a substance corresponding to HCHO also indicated that the quantity of DME supplied significantly influenced the cool flame behavior. However, the rapidity of combustion could not be controlled even by varying the mixing ratios of DME and methane. It was made clear that changes in the ignition timing substantially influence the rapidity of combustion.

As welding residual stress is a primary factor in serious failure or fracture of plants, many testing methods such as X-ray diffraction, hole-drilling, and saw-cutting are used to evaluate this welding residual stress. Instrumented Indentation Testing (IIT) is an attractive testing method for evaluating welding residual stress because it is nondestructive and can be used in-field. The material properties can be obtained by Instrumented Indentation Testing in field using attachments like magnetic device or chain device. In general, the principle of evaluation of residual stress with IIT is based on comparing the load-depth curves obtained from stress-free state and stressed state which are same material. However, as the mechanical properties of welds are altered during welding process, it is difficult to obtain the load-depth curve for stress-free state of welds. In this research, in order to estimate the load-depth curve for the stress-free state, we consider the relation between k value of Kick’s law which is related to the slope of the load-depth curve and the hardness value which is independent of residual stress state. The relation between maximum load and maximum indentation depth which is k value of Kick’s law is similar to the concept of hardness and as a result, the ratio of k value between two materials is almost equal to the ratio of their hardness values. To validate this research, we compare the load-depth curve of stress-free material with the load-depth curve which is estimated from hardness ratio.Copyright © 2015 by ASME

With the improvement of the outcome after esophagectomy for esophageal cancer, patients with metachronous gastric cancer (MGC) in the reconstructed thoracic stomach have been observed in clinical practice. This study is a report of experiences with MGC with an emphasis on clinical pictures and treatment results.Medical records were reviewed of 728 patients who underwent surgery for esophageal cancer at Samsung Medical Center between 1994 and 2004. MGC was defined as follows; (1) diagnosed more than 6 months after esophagectomy, (2) squamous cell carcinoma in histology of the surgically resected esophagus, (3) adenocarcinoma in histology of the stomach biopsy or surgical specimen. The clinicopathologic characteristics of MGC were evaluated.Eight patients (1.1%) of 728 patients were diagnosed with MGC. All patients were male and had a history of active smoking and drinking. The median age at the time of diagnosis of MGC was 67.8 years old (range: 62-76). Three patients (37.5%) were asymptomatic. Two patients (25%) complained of epigastric pain and 3 patients (37.5%) complained of obstructive symptoms including regurgitation, aspiration, dysphagia, and vomiting. The median interval between diagnosis of MGC and esophagectomy was 37 months (range: 8-85). Three MGCs (37.5%) were detected by endoscopic examination but not by computed tomography (CT). Three patients (37.5%) received surgery and were alive without recurrence for 12, 18 and 63 months respectively. One patient (12.5%) received radiation therapy and was alive for 69 months. Four patients (50%) received no treatment because of follow-up loss in 2 patients (25%) and death within days of MGC diagnosis in 2 patients (25%).Favorable outcomes can be obtained by active treatment in patients with MGC after esophagectomy. Regular endoscopic follow-up is important for early detection and more effective treatment of MGC, especially in areas where the incidence of gastric cancer is high.

Internet has become an important source of medical information not only for medical personnels but also for patients. The aim of this study was to evaluate the quality of internet based medical information about 'gastroesophageal reflux' or 'reflux esophagitis' in Korea.The first 15 internet sites using the key words 'gastroesophageal reflux' or 'reflux esophagitis' were retrieved from the 7 most frequently used internet search engines. The quality of information from a total of 108 websites was evaluated using a checklist.Among total 108 sites related to 'gastroesophageal reflux' or 'reflux esophagitis', fifty-six sites (51.8%) were made by hospitals or clinics and 94 sites (87.0%) were made for patients. Of the 108 sites, eleven web sites (10.1%) had more than three JAMA benchmarks (authorship, references, currency, and disclosure). Higher quality sites (at least three JAMA benchmarks) were less likely to contain inaccurate information than lower quality sites (fewer than three JAMA benchmarks)-3/11 (27.2%) vs. 60/97 (61.9%) (p0.01). Despite the fact that articles in the literature emphasized an insufficient evidence to support an association between the lifestyle, dietary behaviors, and GERD, such guidelines continue to be recommended as first-line therapy in most websites.Informations about gastroesophageal reflux disease were incomplete in the majority of medical web sites. These would bring about confusion to patients seeking for an information about GERD through the internet. There is a need for better sources in evidence based informations about gastroesophageal reflux diseases on the web.

Although erythrocyte sedimentation rate (ESR) is included as a laboratory parameter in Truelove and Witts' classification, C-reactive protein (CRP) is also used for severity assessment in ulcerative colitis (UC). Frequently, the discordance between ESR and CRP is observed in clinical practice. The aim of this study was to determine which parameter is more related with clinical activity in UC patients.A total of 155 patients with UC were identified from January 2004 to March 2005. Their medical records were reviewed within these patients, a total of 541 assessments of disease activity were made. Correlation of clinical activity and laboratory tests were evaluated by Pearson's correlation coefficient.Pearson's correlation coefficients of ESR and CRP with clinical symptoms were 0.376 and 0.258, respectively. The correlation coefficient between ESR and CRP was 0.403 (p=0.000). A total of 131 (24.2%) assessments revealed discordance between ESR and CRP. When discordance occurred, the correlation coefficients with clinical symptoms were 0.338 for ESR (p=0.000) and 0.034 for CRP (p0.01). Dividing discordant patients into high ESR/low CRP group and low ESR/high CRP group, the coefficients were 0.420 for ESR and 0.226 for CRP in high ESR/low CRP group, and 0.333 for ESR and 0.068 for CRP in low ESR/high CRP group.The correlation analysis indicates that ESR appears to be a more reliable laboratory parameter of disease activity than CRP in assessing the severity of UC. In particular, when the level of ESR and CRP is discordant, ESR is more useful in assessing the disease activity in UC patients.

Self-assembled InAs/GaAs quantum dots (QDs) were grown by molecular-beam epitaxy and their structure and strain characteristics were studied by using transmission electron microscopy (TEM). TEM investigations were performed by conventional bright field TEM, high-resolution electron microscopy (HREM), annular dark field (ADF) and high angle annular dark filed (HAADF)-STEM techniques. In addition, strain analysis was performed on an atomic-length scale by measuring the space of lattices in HREM. Compressive strain was induced to uncapped QDs from GaAs substrate and the strain increased more than 3.5 % after GaAs cap layer growth. On the other hand, tensile strain by capped QDs was induced to GaAs up to 10 nm over the QDs, i.e. 15 nm over the wetting layer. It was also confirmed that the tensile strain extension resulted in aligned QD growth with 15 nm thick spacers