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We previously proposed a novel method for detecting a rupture of a breast implant using high-resolution ultrasound (HRUS). We therefore conducted this retrospective, observational study to describe its feasibility in making a preoperative diagnosis of rupture of the device in patients receiving an implant-based augmentation mammaplasty.We initially evaluated the medical records of the patients who had received primary or secondary augmentation mammaplasty using a breast implant at other hospitals for aesthetic or reconstructive purposes between August 31, 2017, and August 31, 2020. The patients underwent breast US using the Aplio i600 (Canon Medical System, Otawara, Tochigi, Japan) system with a 7-18 MHz linear transducer. Through a retrospective review of the patients' medical records, we analyzed their baseline and clinical characteristics. Then, we compared an agreement between preoperative diagnosis of rupture on HRUS and findings at reoperation.A total of 29 patients with rupture (55 breasts) were evaluated for the performance of ultrasound in making a diagnosis of rupture. This showed that they were unaware of rupture but they were diagnosed with it on ultrasound. Preoperatively, there were no cases of rupture in 110 left breasts (80.9%) and 107 right breasts (78.7%), which exactly matched to the number of breasts without rupture on HRUS. Moreover, preoperatively, there were 26 (19.1%) and 29 cases (21.3%) of rupture in the left and right breast, respectively, which exactly matched to the number of breasts with rupture on HRUS.In conclusion, patients who are suspected of having rupture of a breast implant should be stringently evaluated for presence of rupture and, if any, its scope using HRUS. Moreover, we propose that surgeons consider using HRUS in making a preoperative diagnosis of rupture of a breast implant.This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

We conducted this study to describe the feasibility of high-resolution ultrasound (HRUS) in characterizing a breast implant in patients receiving an implant-based augmentation mammaplasty.The current study was conducted in a total of 612 patients (n =6 12) receiving an implant-based augmentation mammaplasty at other hospitals between August 31, 2017 and August 31, 2020. Of these, 136 patients (n = 136; 272 breasts) receiving reoperation were included in the current study. We compared between the patients' subjective awareness of a breast implant and its HRUS findings and an agreement between HRUS findings of a breast implant and its findings at reoperation.The proportion of the patients receiving a silicone gel-filled breast implant was increased from 65.44% (89/136) to 81.61% (111/136) on HRUS. Moreover, HRUS was effective in identifying a manufacturer of the device.In conclusion, our results indicate that HRUS is feasible in characterizing a breast implant in patients receiving an implant-based augmentation mammaplasty. But further prospective, large-scale studies are warranted to corroborate our results.This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors. www.springer.com/00266 .

Accurate diagnose of a disease in the early stage is critical to treat the disease properly. To this end, a multitude of biosensors with advanced technologies have been developed to detect the number of biomolecules precisely. In this work, we propose a method for extracting the Stern layer capacitance (Cstern) using the experimental data of silicon nanowire ion-sensitive field-effect transistors (ISFETs) to help improve the accurate detection of target molecules. The proposed method was applied to both pH and virus sensing scheme, and the Cstern value of pH and a virus were extracted as 32 and 26 μF/cm2, respectively. These findings indicated that the extracted Cstern was affected by the size of the ion and protein, which also was verified by a computer-aided simulation. These insights would be useful in the development of charge-based ISFET biosensors.

Objectives: Oleanolic acid, a minor element of ginsenosides, and its derivatives have been shown to have cytotoxicity against some tumor cells. The impact of cytotoxic effect of oleanolic acid 3-acetate on ovarian cancer SKOV3 cells and endometrial cancer HEC-1A cells were examined both in vivo and in vitro to explore the underlying mechanisms. Methods: Cytotoxic effects of oleanolic acid 3-acetate were assessed by cell viability, phosphatidylserine exposure on the cell surface, mitochondrial release of cytochrome C, nuclear translocation of apoptosis-inducing factor, depolarization of mitochondrial transmembrane potential (ΔΨm), and generation of reactive oxygen species (ROS). In vivo inhibition of tumor growth was also assessed with xenografts in immunocompromised mice. Results: Oleanolic acid 3-acetate exhibited potent cytotoxicity toward SKOV3 and HEC-1A cells by decreasing cell viability in a concentration-dependent manner. Importantly, oleanolic acid 3-acetate effectively suppressed the growth of SKOV3 cell tumor xenografts in immunocompromised mice. Furthermore, oleanolic acid 3-acetate induced apoptotic cell death as revealed by loss of ΔΨm, release of cytochrome c, and nuclear translocation of apoptosis-inducing factor with a concomitant activation of many proapoptotic cellular components including poly(ADP-ribose) polymerase, Bcl-2, and caspases-8, caspase-3, and caspase-7. Oleanolic acid 3-acetate, however, caused a decrease in ROS production, suggesting the involvement of an ROS-independent pathway in oleanolic acid 3-acetate–induced apoptosis in SKOV3 and HEC-1A cells. Conclusion: These findings support the notion that oleanolic acid 3-acetate could be used as a potent anticancer supplementary agent against ovarian and endometrial cancer. Oleanolic acid 3-acetate exerts its proapoptotic effects through a rather unique molecular mechanism that involves an unconventional ROS-independent but mitochondria-mediated pathway. Keywords: Apoptosis, Endometrial cancer, Oleanolic acids, Ovarian cancer, Reactive oxygen species

Conventional implantable electrocardiogram monitors are impenetrable to electromagnetic radiation, posing challenges in imaging (i.e. X-rays). In this study, we demonstrate a radiolucent implantable electrocardiogram (ECG) device using graphene sheets and Parylene substrate which allows bypassing of electromagnetic radiation through the implanted device. Evaluated on a canine model, the graphene electrodes detect signals comparable to those recorded using surface electrodes, presenting a valuable and novel modality for medium and long-term monitoring of cardiac rhythm. When compared with current technology, the new system has the distinct advantages of being flexible and radiolucent, thereby improving patient comfort, and avoiding device artifact and shadowing on clinical radiographic imaging.

This study aimed to determine the optimal initial electron beam parameters of a Linac for radiotherapy with a multivariate approach using statistical and machine-learning tools.For MC beam commissioning, a 6 MV Varian Clinac was simulated using the Geant4 toolkit. The authors investigated the relations between simulated dose distribution and initial electron beam parameters, namely, mean energy (E), energy spread (ES), and radial beam size (RS). The goodness of simulation was evaluated by the slope of differences between the simulated and the golden beam data. The best-fit combination of the electron beam parameters that minimized the slope of dose difference was searched through multivariate methods using conventional statistical methods and machine-learning tools of the scikit-learn library.Simulation results with 87 combinations of the electron beam parameters were analyzed. Regardless of being univariate or multivariate, traditional statistical models did not recommend a single parameter set simultaneously minimizing slope of dose differences for percent depth dose (PDD) and lateral dose profile (LDP). Two machine learning classification modules, RandomForestClassifier and BaggingClassifier, agreed in recommending (E = 6.3 MeV, ES = ±5.0%, RS = 1.0 mm) for predicting simultaneous acceptance of PDD and LDP.The machine learning with random-forest and bagging classifier modules recommended a consistent result. It was possible to draw an optimal electron beam parameter set using multivariate methods for MC simulation of a radiotherapy 6 MV Linac.

Accurate circuit simulation reflecting physical and electrical stress is of importance in indium gallium zinc oxide (IGZO)-based flexible electronics. In particular, appropriate modeling of threshold voltage (VT) changes in different bias and bending conditions is required for reliability-aware simulation in both device and circuit levels. Here, we present SPICE compatible compact modeling of IGZO transistors and inverters having an atomic layer deposition (ALD) Al2O3 gate insulator on a polyethylene terephthalate (PET) substrate. Specifically, the modeling was performed to predict the behavior of the circuit using stretched exponential function (SEF) in a bending radius of 10 mm and operating voltages ranging between 4 and 8 V. The simulation results of the IGZO circuits matched well with the measured values in various operating conditions. It is expected that the proposed method can be applied to process improvement or circuit design by predicting the direct current (DC) and alternating current (AC) responses of flexible IGZO circuits.

Miniaturized flexible microelectrode arrays are desirable for small-area surface electromyography (sEMG) to detect the electrical activity generated by muscles in a specific area of the body. Here, we present a flexible 8-channel microelectrode array with electrodes of diameter 150&ndash, 300 &mu, m for small-area sEMG recordings. The microelectrode arrays based on a flexible Parylene C substrate recorded the sEMG signals from a curved skin surface with a maximum signal-to-noise ratio (SNR) of 21.4 dB. The sEMG signals recorded from a small area of 17671&ndash, 59325 &mu, m2 showed a clear distinction between the signal and noise. Further, the sEMG data were analyzed in the frequency domain by converting the signals via fast Fourier transform (FFT), and it was verified that the proposed microelectrode could reliably record multichannel sEMGs over a small area. Moreover, a maximum voluntary contraction (MVC) experiment was performed to confirm the recording capability of the microelectrode array, which showed consistency with the previous reports. Finally, we demonstrated the effects of the electrode size by comparing the results for two different electrode sizes. When the electrode size was increased 3.37 times, the root-mean-square value of the amplitude (Vrms) increased 2.64 times, consequently increasing the SNR from 16.9 to 21.4 dB. This study demonstrates the expanded utility of Parylene-based flexible microelectrode arrays.

Cyanoacrylate closure for the treatment of incompetent saphenous veins does not cause thermal damage and demonstrates satisfactory outcomes with rapid recovery. However, the characteristics of phlebitis-like abnormal reaction (PLAR), the most common adverse event after cyanoacrylate closure, have not been clarified. Moreover, it differs from typical phlebitis after thermal ablation. The objective of our study is to investigate the clinical features of PLAR after cyanoacrylate closure and to report its management.A total of 160 patients with 271 incompetent saphenous veins (great saphenous veins, 201; small saphenous veins, 70) underwent cyanoacrylate closure with the VenaSeal™ system. We defined PLAR as any unusual skin condition that develops suddenly, such as erythema, itching, swelling, and pain/tenderness, over the treated veins several days after cyanoacrylate closure. Oral antihistamines and intravenous dexamethasone were administered to manage PLAR.Of the 271 treated veins, 69 experienced PLAR (25.4%). The mean time of occurrence was 13.6 ± 4.6 days after treatment. The rate of occurrence of erythema, itching, swelling, and pain/tenderness were 92.2%, 91.2%, 66.2%, and 48.5%, respectively. The occurrence of PLAR was significantly higher for great saphenous veins than for small saphenous veins (P 0.001). Occurrences were more frequent in cases with a suprafascial great saphenous vein of length10 cm than in cases with a subfascial great saphenous vein (P = 0.001). The proportion of patients who reported swelling decreased by more than half after the administration of oral antihistamine. The pain score on the 10th day also decreased significantly after the administration of antihistamine (P = 0.006).PLAR must be distinguished from classic phlebitis. We believe that PLAR is a type IV hypersensitivity reaction due to a foreign body, and in our experience, antihistamines or steroids are effective for the prevention and management of PLAR.

Field-effect transistors (FETs) combined with a microfluidic system allow for the electrical detection of charged materials moving in a microfluidic channel. Here, we demonstrate trench-shaped silicon FETs with the combination of a microfluidic channel that can be used for simultaneous electrical and optical detection of charged fluorescent beads. The n-channel silicon trench FETs have a maximum transconductance of 1.83 × 10−5 S at near-zero gate bias voltage, which is beneficial for the high sensitivity of electrical detection. The optical transparency and physical robustness of the integrated microfluidic channel are achieved by a polydimethylsiloxane (PDMS)/glass hybrid cover combining the good sealing characteristics of PDMS, and the thin and flat properties of glass. Device evaluation methodologies and measurement approaches are also presented demonstrating a synchronized time-lapse imaging and electronic detection of bead transport. The proposed device and design consideration could advance the promise of electronic sensing to measure potential differences induced by charged analytes.

Dielectrophoresis using multi-electrode arrays allows a non-invasive interface with biological cells for long-term monitoring of electrophysiological parameters as well as a label-free and non-destructive technique for neuronal cell manipulation. However, experiments for neuronal cell manipulation utilizing dielectrophoresis have been constrained because dielectrophoresis devices generally function outside of the controlled environment (i.e. incubator) during the cell manipulation process, which is problematic because neurons are highly susceptible to the properties of the physiochemical environment. Furthermore, the conventional multi-electrode arrays designed to generate dielectrophoretic force are often fabricated with non-transparent materials that confound live-cell imaging. Here we present an advanced single-neuronal cell culture and monitoring platform using a fully transparent microfluidic dielectrophoresis device for the unabated monitoring of neuronal cell development and function. The device is mounted inside a sealed incubation chamber to ensure improved homeostatic conditions and reduced contamination risk. Consequently, we successfully trap and culture single neurons on a desired location and monitor their growth process over a week. The proposed single-neuronal cell culture and monitoring platform not only has significant potential to realize an in vitro ordered neuronal network, but also offers a useful tool for a wide range of neurological research and electrophysiological studies of neuronal networks.

Electrical stimulation using implantable electrodes is widely used to treat various neuronal disorders such as Parkinson's disease and epilepsy and is a widely used research tool in neuroscience studies. However, to date, devices that help better understand the mechanisms of electrical stimulation in neural tissues have been limited to opaque neural electrodes. Imaging spatiotemporal neural responses to electrical stimulation with minimal artifact could allow for various studies that are impossible with existing opaque electrodes. Here, we demonstrate electrical brain stimulation and simultaneous optical monitoring of the underlying neural tissues using carbon-based, fully transparent graphene electrodes implanted in GCaMP6f mice. Fluorescence imaging of neural activity for varying electrical stimulation parameters was conducted with minimal image artifact through transparent graphene electrodes. In addition, full-field imaging of electrical stimulation verified more efficient neural activation with cathode leading stimulation compared to anode leading stimulation. We have characterized the charge density limitation of capacitive four-layer graphene electrodes as 116.07-174.10 μC/cm

This study was conducted as part of an endeavor to improve the risk management system of radiation therapy departments in the Republic of Korea. An online survey on the status and perception of Korea's medical physicists on risk management in radiation therapy was carried out. A total of 40 domestic radiation oncology departments participated. This survey is divided into three categories: (1) work environment; (2) risk management status; and (3) opinions on how to improve risk management. Based on the results of the survey, the conclusions that can be derived are (1) the majority of respondents have a high interest in the risk management of radiation therapy; (2) the lack of staffing is one cause of risk management difficulties; (3) a risk-related terminology and classification system at the national or professional association level are required; (4) each hospital should create a voluntary reporting system for the handling of incidents; (5) medical physicists should establish incident reporting, analysis and countermeasures; and (6) government should develop education and training programs. It was confirmed that the current risk management system should be changed by education in the hospital and at the national level in order to improve risk management related to radiation therapy. In addition, it was recognized that a dedicated staff and a risk management certification system and organization for patient safety in radiotherapy are needed.

A number of peripheral nerve interfaces for nerve stimulation and recording exist for the purpose of controlling neural prostheses, each with a set of advantages and disadvantages. The ultimate goal of neural prostheses is a seamless bi-directional communication between the peripheral nervous system and the prosthesis. Here, we developed an interfacing electrode array, the "cuff and sieve electrodes" (CASE), integrating microfabricated cuff and sieve electrodes to a single unit, to decrease the weaknesses faced by these electrode designs in isolation. This paper presents the design and fabrication of CASE with ex vivo and in vivo testing towards chronic application.Electroplating on electrode sites was performed to improve electrical properties of CASE. The surface morphology and chemical compound were characterized using scanning electron microscopy and energy-dispersive spectroscopy, respectively. Electrochemical impedance spectroscopy and cyclic voltammetry were performed to evaluate the electrical properties of CASE and determine viability for in vivo applications. Terminal CASE implantations were performed in a rat sciatic transection model to test the ease of implantation and capacity to write sensory information into the biological system.The modified platinum film resulted in reducing impedance magnitude (9.18 kΩ and 2.27 kΩ) and increasing phase angle (over 70°). CASE stimulation of the sciatic nerve at different amplitudes elicited significantly different cortical responses (p0.005) as demonstrated by somatosensory evoked potentials, recorded via micro-electrocorticography.The ability to elicit cortical responses from sciatic nerve stimulation demonstrates the proof of concept for both the implantation and chronic monitoring of CASE interfaces for innovative prosthetic control.

Controlling the emission wavelength by the quantum confinement or the size effect of silicon quantum dots (Si QDs) has a limitation in that it can be only approximately 600 nm or above. To overcome this limitation, in the recent decade, numerous studies have been conducted for reproducing the entire visible range from blue to red from Si QDs by their surface functionalization. In this study, we fabricated alkyl- and amine-passivated Si QDs and investigated their emission mechanism following surface functionalization. We interpreted the emission mechanism of the surface-functionalized Si QDs by combined experimental analysis of the decay time dynamics and density functional theory-based model calculation of the highest occupied molecular orbital-lowest unoccupied molecular orbital electronic structures. Our comprehensive studies could provide insight into the debated problems of the luminescence mechanism of surface-functionalized Si QDs.

A technique that can be used to viably create triaxially strained bilayer graphene on any desirable location by simple patterning was developed. Unlike the conventional graphene strain engineering methods, the photolithographically defined spoke patterns and compressive strained Si3N4 layer deposited by plasma-enhanced chemical vapor deposition (PECVD) system enable the creation of locally confined triaxial strained bilayer graphene at the desire location by forming a unique tristar shaped wrinkle. The tristar shaped wrinkle was investigated with high resolution micro-Raman spectroscopy and atomic force microscopy (AFM) analyses, and confirmed that 0.38% of maximum triaxial compressive strain was created. Mechanical simulation was used to verify the strain distribution and confirm the strain value which was calculated from the Raman spectroscopy and AFM profile. The technique presented here not only provides a practical route to the creation of strained graphene at desired locations but also offers the potential of the creation of multiaxial strain in the graphene for various types of graphene-based electronic and optoelectronic devices.

In radiation therapy, the carbon beams has more advantages with respect to biological properties then a proton beam. The carbon beam has a high linear energy transfer (LET) to the medium and a higher relative biological effectiveness (RBE). To design the spread-out Bragg peak (SOBP) of biological dose for a carbon beam, we propose a practical method using the linear-quadratic (LQ) model and the Geant4-based Monte Carlo simulation code. Various Bragg peak profiles and LETs were calculated for each slice in the target region. To generate an appropriate biological SOBP, we applied a set of weighting factors, which are power functions in terms of energy steps, to each obtained physical dose. The designed biological SOBP showed a uniformity of 1.34%.

The active scanning technique is a pencil beam delivery method in particle therapy. The active scanning beam delivery system consists of a beam scanner, beam monitor, energy modulator, and related programs, such as the irradiation control and planning programs. A proposed prototype active scanning system was designed and installed on MC-50 at the Korea Institute of Radiological and Medical Science (KIRAMS) with a 45-MeV proton beam. The laminated magnetic yoke of the scanning magnet supported fast ramping. The beam intensity and the beam profile monitors were designed for measuring the beam’s properties. Both the range shifter and the ridge filter modulate the incoming beam energy. The LabVIEW®-based beam-irradiation-control program operates the system in a sequential operation manner for use with the MC-50 cyclotron. In addition, an in-housecoded irradiation-planning program generates an optimal irradiation path. A scanning experiment was successfully completed to print the logo of the Korea Heavy Ion Medical Accelerator (KHIMA) on GaF film. Moreover, the beam’s position accuracy was measured as 0.62 mm in the x-direction and as 0.83 mm in the y-direction.

Purpose Conventional full-field flash electroretinography (ERG) yields a single response waveform that can be useful in the early detection and diagnosis of many diseases affecting the retina. It is an objective measurement that probes the entire retina. However, localized areas of dysfunction have relatively small influence on ERG amplitudes compared to normal ranges. Here we evaluate the use of corneal potential maps obtained in response to full-field flash stimuli for sensitivity to local areas of retinal damage. Methods A contact lens electrode array was used to record 25 ERG waveforms simultaneously following saturating full-field flash stimuli (multi-electrode electroretinography, meERG) in rats. Waveforms were evaluated for a-wave and b-wave amplitudes; these values were normalized and further evaluated for spatial differences across the corneal surface. Cluster analysis and a support vector machine approach were used to classify meERG responses from healthy eyes and eyes with central (photocoagulation) or peripheral (cryocoagulation) experimental lesions. Results A normative normalized corneal potential map was obtained from healthy eyes (n = 26). Corneal potential maps from eyes with experimental lesions (n = 13) could be classified with sensitivity and specificity of approximately 80% based solely on the normalized spatial distribution of corneal potentials, that is, with no knowledge of absolute amplitudes. Conclusions Corneal potential maps obtained in response to full-field flash stimuli are altered in eyes with scotomas in the central and far-peripheral retina. The meERG approach yields useful spatial information following a single brief flash, analogous to body-surface potential maps used to evaluate heart and brain.

To evaluate the viability of frozen embryos generated by intracytoplasmic sperm injection (ICSI) with frozen testicular spermatozoa.A total of 68 fresh embryo transfer (ET) cycles and 85 subsequent frozen-thawed ET (FET) cycles were grouped according to the source of spermatozoa: fresh testicular spermatozoa (TESE) or frozen-thawed testicular spermatozoa (t-TESE).There were no significant differences in the age of female patients, number of oocytes, or fertilization rates in fresh ET cycles with TESE (TESE-fresh ET) versus t-TESE (t-TESE-fresh ET). The rate of embryo survival after thawing (95.7 % vs. 94.0 %) was similar in frozen ET cycles (FET) with TESE (TESE-FET) and with t-TESE (t-TESE-FET). While there were significant differences in the proportion of good quality embryos, no statistical differences were found in the pregnancy or clinical abortion rates between the two groups. Moreover, delivery rates were not significantly different.Although the proportion of good quality embryos was affected by cryopreservation of testicular tissue, embryo survival rate was not. As well, subsequent pregnancy could be achieved successfully via t-TESE-FET cycles. Therefore, FET is not affected by the cryopreservation of testicular tissue, and avoids further oocyte retrieval and TESE procedures.

The monitoring and abnormality warning of marine diesel engine are important to take appropriate responses for safety navigation. If maintenance engineers do not take appropriate response because of diag- nosis mistakes, it will occur a nasty accident. Therefore, we need integrated monitoring and diagnosis system for supporting a diagnosis objectively. In this paper, we analyze time-series data which measured by real-time, monitor the changing of conditions and trends of the analyzed data. Furthermore, we design and implement a monitoring and diagnosis system for objective supporting of real-time diagnosis. When the integrated monitor- ing and diagnosis system is adopted, it can help to improve stability of marine diesel engine by providing ab

In this paper, we develop a facility management system which provides fault effect and replacement alarm function of each component for supporting effective maintenance of facility. To do this, we use weight-ing method to each component, calculate importance of each component, and make them to hierarchy structure using bill of materials of facility. Also, we draw fault cause and fault effect of components based on failure modes effects and criticality analysis, and define criteria of severity, occurrence and detection to get risk pri-ority number. To apply these concepts, we develop and test the facility management system to verify its practicality. In the future, we expect the developed system to apply many domains such as maintenance of ship and offshore plant. Keywords: Facility management system, Bill Of Materials, Failure Modes Effects and Criticality Analysis, Replacement alarm, Maintenance 1. 서 론 도시가 발전하고 IT 기술이 발달함에 따라 우리 주변의 각종 시설물 또한 복잡화 및 다양화되고 있다. 이러한 이유로 인해 IT 기술을 접목시켜 각종 시설물을 보다 효율적이고 통합적으로 관리하기 위한 많은 연구가 진행되고 있다. 한편, 시설물은 장비로 구성되어 있으며, 한 장비는 여러 부품으로 구성되어 있고, 각 부품은 수명 주기(life cy

Tool steels have a large range of applications including hot and cold working of metals and injection molding of plastic or light alloys. High-speed steel (HSS) is specifically used for cutting tools and for components subjected to extreme wear conditions, because of its high strength, wear resistance, hardness, toughness, and fatigue resistance. The microstructure of HSS can be described as a metallic matrix iron composite containing a dispersion of hard and wear-resistant carbides. Specimens were manufactured experimentally from T42 powder (50–80 vol%) and mixed binder (20–50 vol%) by powder injection molding. The binders (green parts) were debound in n-hexane solution at 60 °C for 8 h and thermally debound in a mixed N2–H2 gas atmosphere for 8 h. Specimens were sintered under high vacuum (10−5 Torr) at different temperatures. When sintering was performed at 1,260 °C, the specimen sintered under high vacuum had the highest hardness (550 Hv). The carbides were smaller (1 μm) and well distributed. Grain size was 10 μm. When sintering was performed under high vacuum at temperatures above 1,280 °C the carbides changed to eutectic carbide located at grain boundaries. Grain growth was observed. Specimens sintered at other pressures had lower density and hardness than those sintered under high vacuum.

The beam irradiation system for particle therapy can use a passive or an active beam irradiation method. In the case of an active beam irradiation, using a ridge filter would be appropriate to generate a spread-out Bragg peak (SOBP) through a large scanning area. For this study, a ridge filter was designed as an energy modulation device for a prototype active scanning system at MC-50 in Korea Institute of Radiological And Medical Science (KIRAMS). The ridge filter was designed to create a 10 mm of SOBP for a 45-MeV proton beam. To reduce the distal penumbra and the initial dose, [DM] determined the weighting factor for Bragg Peak by applying an in-house iteration code and the Minuit Fit package of Root. A single ridge bar shape and its corresponding thickness were obtained through 21 weighting factors. Also, a ridge filter was fabricated to cover a large scanning area (300 × 300 mm2) by Polymethyl Methacrylate (PMMA). The fabricated ridge filter was tested at the prototype active beamline of MC-50. The SOBP and the incident beam distribution were obtained by using HD-810 GaF chromatic film placed at a right triangle to the PMMA block. The depth dose profile for the SOBP can be obtained precisely by using the flat field correction and measuring the 2-dimensional distribution of the incoming beam. After the flat field correction is used, the experimental results show that the SOBP region matches with design requirement well, with 0.62% uniformity.

A control system of the 14.5 GHz electron cyclotron resonance (ECR) ion source has been designed and developed in KHIMA(Korea Heavy Ion Medical Accelerator) project which will use C6+ ions for heavy ion therapy. Production of the selected ion beam in stable operation with safety is a development goal with flexibility by easy access and modification which are necessary during development process with an accelerator. The control system of the ECR ion source system consists of electric control cabinet (ECC) as hardware and main control program (MCP) as software, respectively. ECC developed to manage power and control flow with electric components and controllers controls the injection system, RF system, high voltage & extraction system, analyzing system, vacuum system, cooling system, diagnosis system and safety system. MCP is the supervisory program developed for effective automation and data acquisition by LabVIEW-based graphical programming. The isolated network from a control computer to ECC and bleeder resistors in a steel plate box composed by the simulation result for high voltage power supplies increase reliability and safety. The performance of the developed control system has been verified successfully by beam extraction of C4+ ion from CO2 as main gas and He as support gas through an analyzing magnet and a faraday cup with the acquired spectrum at the control system. After optimization with C4+ ions, measurement of characteristics of C6+ ions including emittance of the ion beam will be planned early 2013. Also, quantity of C6+ ions in the same charge to mass ratio will be estimated by using 13CO2 as main gas and He as support gas.

Flexible graphene transistors built on a biocompatible Parylene C substrate would enable active circuitry to be integrated into flexible implantable biomedical devices. An annealing method to improve the performance of a flexible transistor without damaging the flexible substrate is also desirable. Here, we present a fabrication method of a flexible graphene transistor with a bottom-gate coplanar structure on a Parylene C substrate. Also, a current annealing method and its effect on the device performance have been studied. The localized heat generated by the current annealing method improves the drain current, which is attributed to the decreased contact resistance between graphene and S/D electrodes. A maximum current annealing power in the Parylene C-based graphene transistor has been extracted to provide a guideline for an appropriate current annealing. The fabricated flexible graphene transistor shows a field-effect mobility, maximum transconductance, and a Ion/Ioff ratio of 533.5 cm2/V s, 58.1 μS, and 1.76, respectively. The low temperature process and the current annealing method presented here would be useful to fabricate two-dimensional materials-based flexible electronics.

Tool steels serve a large range of applications including hot and cold workings of metals and injection mouldings of plastics or light alloys. The high speed steels (HSS) are specifically used as cutting tools and wear parts because it has high strength, wear resistance and hardness along with appreciable toughness and fatigue resistance. From the view of HSS microstructure, it can be described as metallic matrix composites formed by a ferrous with a dispersion of hard and wear resistant carbides. The experimental specimens were manufactured using the PIM with T42 powders (50~80 vol.%) and polymer (20~50 vol.%). The green parts were debinded in n-hexane solution at for 8 hours and thermal debinded at an mixed gas atmosphere for 8 hours. Specimens were sintered in high vacuum ( Torr) and various temperatures.

HSS has high strength, wear resistance, and hardness together with an appreciable toughness and fatigue resistance. PIM has received attention owing to its ability to shape without additional processes. The experimental specimens were manufactured using PIM with T42 powders (59 vol.%) and polymer (41 vol.%). The green parts were solvent debound in n-Hexane at 60 °C for 24 hours and further thermally debound in a N2-H2 mixed gas atmosphere for 18 hours. The specimens were then sintered in a vacuum (10−5 mtorr), hydrogen and nitrogen gas atmosphere. In the vacuum, the specimen sintered at 1240 °C had the highest hardness at 520 Hv. In this condition, the carbides were well-distributed and located in the grain. The grain size was 10 μm, and the carbide size was 1 μm. When sintering in a vacuum at over 1260 °C, the carbides converted to eutectic carbide and were located at the grain boundary. Grain growth was observed. The specimens sintered in a nitrogen atmosphere had a lower density and hardness than that produced in the vacuum.

Citation Park D-W, Lee S-K, Hong SR, Han A-R, Kwak-Kim J, Yang KM. Expression of kisspeptin and its receptor GPR54 in the first trimester trophoblast of women with recurrent pregnancy loss (RPL). Am J Reprod Immunol 2012; 67: 132–139 Problem Kisspeptin and its receptor GPR54 play a major role in trophoblast invasion. The expression of kisspeptin and GPR54 in trophoblast and decidua and their relationship with decidual and peripheral blood natural killer (NK) cells are investigated in women with RPL. Method of study Trophoblast and decidual tissues were collected from 38 RPL women who miscarried a genetically normal fetus and 14 women who had elective abortion. Kisspeptin, GPR54, and decidual NK cells were investigated with immunohistochemistry, and peripheral blood NK cells were analyzed by flow cytometry. Results Kisspeptin expression in syncytiotrophoblast was significantly decreased in RPL women with normal (

In order to synthesize the fine compound iron-doped nickel disulfide (NiS2) with environmentally friendly nickel, sulfur and iron powders, mechanical alloying (MA) was conducted for 8 hrs with SPEX Mill at a speed of 1000 rpm. In this process, stearic acid was added as a kind of process control agents (PCAs) to prevent the excessive cold welding. Meanwhile, for the purpose of getting nanocrystalline of Fe-doped NiS2powder particles to improve the contact areas between the active materials, the wet milling process was also done for 30 hrs with normal hexane (C6H14) as a solvent PCA. The prepared powders were characterized by FE-SEM, XRD, EPMA, EDS and TEM. Finally, the charge/discharge properties of Li/Fe-doped NiS2cells were investigated at room temperature by employing 1 M LiCF3SO3(lithium trifluoromethanesulfonate) dissolved in TEGDME (tetraethylene glycol dimethylether) as the electrolyte. The initial discharge capacity of Li/Fe-doped NiS2cell using wet milled powders as the cathode material is 792 mAh/g, which may indicate its high energy density and good future as cathode materials for lithium-ion batteries.