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Objective This study aimed 1) to investigate the clinical characteristics of amniotic fluid embolism (AFE) cases clinically diagnosed by maternal fetal medicine (MFM) specialists in Korea, 2) to check the disagreement with 4 recently proposed criteria by the Society for Maternal-Fetal Medicine (SMFM) for research purpose, and 3) to compare maternal outcomes between cases satisfying all 4 criteria and cases with at least 1 missing criterion. Methods This study included 12 patients clinically diagnosed with AFE from 7 referral hospitals in Korea. We collected information, including maternal age, symptoms of AFE, the amount of transfusion, and maternal mortality. Results The median maternal age was 33 years (range, 28–40 years). Regarding symptoms, cardiovascular arrest, hypotension, respiratory compromise, clinical coagulopathy, and neurologic signs were observed in 41.7%, 83.3%, 83.3%, 100%, and 66.7% of the cases, respectively. Among the 12 cases, 5 women died and 2 suffered severe neurologic disability, showing an intact survival rate of 41.7%. Disagreement with all 4 criteria proposed by the SMFM was found in 66.7% of the cases, due to the lack of criteria for disseminated intravascular coagulation or strict onset time (

Purpose We investigated the validity of quad serum markers for the prediction of adverse pregnancy outcome (APO) in women with antiphospholipid antibody syndrome (APS). Methods We included 75 women with APS delivered at our institution. APO was defined as stillbirth, small for gestational age (SGA), severe preeclampsia, or preterm delivery. First, we compared clinical characteristics between patients with or without composite APO. Second, we compared the rate of APO according to abnormal level of quad serum markers. Lastly, receiver operating characteristic (ROC) curve analysis was performed. Results APS mothers with APO showed higher median α-fetoprotein (AFP) and inhibin A compared with those without APO. They were also associated with higher rates of positive risk of Down syndrome and neural tube defect. Elevated AFP, human chorionic gonadotropin (hCG), and inhibin A level was associated with higher rates of stillbirth, SGA, preterm delivery, and composite APO. ROC curve for prediction of stillbirth revealed an area under the curve of 0.835 for AFP, 0.781 for hCG, and 0.932 for inhibin A. For composite APO, the area under the ROC curve was 0.692 for AFP and 0.810 for inhibin A. Conclusion Elevated AFP, hCG, and inhibin A in women with APS demonstrated a high predictive value for APO, especially stillbirth.

This study aimed to investigate whether a difference in gestational age according to biparietal diameter (BPD) and abdominal circumference (AC) could be a clinically useful predictor of placental abruption during the intrapartum period. This retrospective cohort study was based on singletons who were delivered after 32 + 0 weeks between July 2015 and July 2020. We only included cases with at least two antepartum sonographies available within 4 weeks of delivery (n = 2790). We divided the study population into two groups according to the presence or absence of placental abruption and compared the clinical variables. The incidence of placental abruption was 2.0% (56/2790) and was associated with an older maternal age, a higher rate of preeclampsia, and being small for the gestational age. A difference of &gt, 2 weeks in gestational age according to BPD and AC occurred at a higher rate in the placental abruption group compared to the no abruption group (&gt, 2 weeks, 21.4% (12/56) vs. 7.5% (205/2734), p &lt, 0.001, &gt, 3 weeks, 12.5% (7/56) vs. 2.0% (56/2734), p &lt, 0.001). Logistic regression analysis revealed that the differences of &gt, 2 weeks and &gt, 3 weeks were both independent risk factors for placental abruption (odds ratio (OR) (95% confidence interval), 2.289 (1.140–4.600) and 3.918 (1.517–9.771), respectively) after adjusting for maternal age, preeclampsia, and small for gestational age births. We identified that a difference in gestational age of &gt, 2 weeks between BPD and AC could be an independent predictor of placental abruption.

Background Neurodegeneration, an early event in the pathogenesis of diabetic retinopathy (DR), precedes clinically detectable microvascular damage. Autophagy dysregulation is considered a potential cause of neuronal cell loss, however underlying mechanisms remain unclear. The mechanistic target of rapamycin (mTOR) integrates diverse environmental signals to coordinate biological processes, including autophagy. Here, we investigated the role of mTOR signaling in neuronal cell death in DR. Methods Diabetes was induced by a single intraperitoneal injection of streptozotocin and tissue samples were harvested at 1, 2, 3, 4, and 6 months of diabetes. Early-stage of DR was investigated in 1-month-diabetic mice treated with phlorizin (two daily subcutaneous injections at a dose of 200 mg/kg of body weight during the last 7 full days of the experiment and the morning of the 8th day, 3 h before sacrifice) or rapamycin (daily intraperitoneal injections, at a dose of 3 mg/kg for the same period as for phlorizin treatment). The effect of autophagy modulation on retinal ganglion cells was investigated in 3-months-diabetic mice treated with phlorizin (two daily subcutaneous injections during the last 10 full days of the experiment and the morning of the 11th day, 3 h before sacrifice) or MHY1485 (daily i.p. injections, at a dose of 10 mg/kg for the same period as for phlorizin treatment). Tissue samples obtained from treated/untreated diabetic mice and age-matched controls were used for Western blot and histologic analysis. Results mTOR-related proteins and glucose transporter 1 (GLUT1) was upregulated at 1 month and downregulated in the following period up to 6 months. Diabetes-induced neurodegeneration was characterized by an increase of apoptotic marker—cleaved caspase 3, a decrease of the total number of cells, and NeuN immunoreactivity in the ganglion cell layer, as well as an increase of autophagic protein. Insulin-independent glycemic control restored the mTOR pathway activity and GLUT1 expression, along with a decrease of autophagic and apoptotic proteins in 3-months-diabetic mice neuroretina. However, blockade of autophagy using MHY1485 resulted in a more protective effect on ganglion cells compared with phlorizin treatment. Conclusion Collectively, our study describes the mechanisms of neurodegeneration through the hyperglycemia/ mTOR/ autophagy/ apoptosis pathway.

To achieve rational design in waves for a submerged floating tunnel which has emerged as a new offshore transportation infrastructure, it's necessary to understand its hydrodynamic behavior. For simple but accurate estimation of hydrodynamic forces, a theoretical method is proposed and the tests with physical models in a wave flume were carried out for verification. Morison's equation was used to estimate wave loads composed of inertia force and drag force. Forces calculated by applying the linear wave theory to Morison's equation coincided well with those measured by the tests. The test results showed that mooring systems played a significant role in the movement of the submerged floating tunnel in waves. A pendulum model could be used to describe the motion of the submerged floating tunnel with a single vertical mooring. Based on the verified relations, a simple slack condition which causes the submerged floating tunnel to be unstable was also proposed. The simplified approach proposed by this study proved to be useful in designing the submerged floating tunnel in the initial stage.

Objective We evaluated the effect on treatment using the new International Association of Diabetes and Pregnancy Study Group (IADPSG) criteria for gestational diabetes mellitus (GDM) diagnosis. Methods Singleton pregnant women whose plasma glucose levels were ≥140 mg/dL on the 50 g glucose challenge test (GCT) underwent 75 g oral glucose tolerance for GDM diagnosis. During the first half of the study period, GDM was diagnosed using 2 abnormal values by Carpenter-Coustan (C-C) criteria. In the second half of the study period, 1 or more abnormal values by IADPSG criteria were used for GDM diagnosis. Pregnant women were classified into 5 groups: normal 50 g GCT, positive 50 g GCT but non-GDM, GDM by IADPSG criteria and non-treated, GDM by IADPSG criteria and treated, GDM by C-C criteria and treated. The odds ratios (ORs) for large for gestational age (LGA) and macrosomia were analyzed. Results Of the 2,678 patients, the frequency of GDM diagnosed by C-C and IADPSG criteria was 2.6% and 7.5%. ORs (95% confidence intervals [CIs]) for LGA and macrosomia in the group with GDM by IADPSG criteria and non-treated were 2.81 (95% CI, 1.47–5.38) and 2.84 (95% CI, 1.08–7.47). The risk of LGA and macrosomia did not increase in the group with GDM by IADPSG criteria and treated. Conclusion The risk of LGA and macrosomia for mild GDM diagnosed solely by IADPSG criteria depends on whether they are treated or not. Treatment of GDM based on IADPSG criteria reduces the risk of excessive fetal growth. Trial Registration Clinical Research Information Service Identifier: KCT0000776

Purpose: This study was designed to examine how Behavioral and Psychological Symptoms of Dementia (BPSD) in elders with dementia were related to Activities of Daily Living (ADLs) and Instrumental Activities of Daily Living (IADLs) for these elders living in a local community. Methods: This was a retrospective study including 16,596 elders with dementia registered in the Seoul Dementia Management Project Database during the period from June 2007 to May 2013 and who completed the Seoul Dementia Assessment Packet (SDAP). Data were analyzed using descriptive statistics, Pearson correlation, Spearman rank order correlation and hierarchical multiple regression analyses. Results: Prevalence of BPSD among the elders with dementia living at home was 76.3%. Findings from the hierarchical multiple regression analysis to identify how BPSD predicts ADLs and IADLs revealed that while BPSD in the elders was a factor that significantly predicts both ADLs (β=.22, p

Purpose: This study, on the basis of a structural model that includes nurse image, image determinants, and self-esteem of Cambodian nursing students influenced by the Korean nursing education system, demonstrates distinctions between senior and junior according to experience in clinical practice. Methods: Data were collected via a questionnaire from 194 nursing students in Cambodia and subsequently analyzed using the STATA IC 12 program. Results: First, image determinants and their sub-factors-subjective, institutional, and media-effect both the nurse image and self-esteem of nursing students. Second, the study confirms that nurse image has no significant effect on self-esteem. Also, the individual factor, a sub-factor of nurse image, possesses a weak relationship with nurse image. Third, the structural model mediating between senior and junior reveals differences resulting from experiences derived from clinical practice. Conclusion: The study has significance in that Cambodian nursing students, who are rarely studied in terms of nurse image, have been systemically analyzed via a structural model incorporating image determinants and self-esteem.

해중철도는 Fig. 1과 같이 수면 하에서 중력을 초과하는 부력이 계류장치의 인장력으로 평형을 이루고 있는 튜브형 구조물로서, 내부에 열차가 운행할 수 있는 혁신적인 미래 철도 인프라이다. 해중철도의 실현을 위해 다양한 연구가 이 루어지고 있으나[1,2], 해중철도의 실제 건설 및 운영을 위 해서는 해중철도를 둘러싸고 있는 환경의 요인을 정확히 파 악하고 적절한 대비책을 세우는 것이 필수적이다. 해중철도는 부력과 장력의 평형으로 안정된 상태를 유지 하고 있으나, 해수면에서 발생되는 파도의 영향을 지속적으 로 받고 있다. 해수면의 파도는 해저면의 깊이 가 깊을 때 에는 지수적으로 입자의 속도가 감소하는 특성을 가지고 있 으나, 해저면의 깊이가 깊지 않을 때 에는 해수면의 입자의 운동이 상당한 깊이까지 영향을 미친다[3]. 또한 해중철도의 수명을 일반 철도 구조물과 같이 100년으로 잡는다면, 100 년 주기 파도의 파고와 이에 따른 파랑 하중은 상당하므로 파랑 하중에 대비한 해중철도 구조체의 설계는 필수적이라 하겠다. 본 연구 에서는 파도에 의한 하중을 받는 해중철도 의 유체력을 평가하고, 설계에 반영하기 위해 이론적 파력 계산식을 제시하여 파력을 계산한 후, 실험을 통해 비교 분 석 함으로 이론 계산식의 유용성을 확인하고, 해중철도 설 계를 위한 기본 자료로 활용하고자 한다. 이를 위해, 선형 미소진폭 파이론(linear small amplitude wave theory)을 이 용하여 파입자의 속도 및 가속도를 구하고 이를 기초 로 해 중철도 터널 단면에 작용하는 유체력을 계산 하는 방법을 제 Abstract In order to rationally design a new conceptual submerged floating railway, prediction of wave forces applied to the structure is very important. In this paper, equations to calculate such forces based on hydrodynamic theories were proposed and model tests were carried out. Inertia forces and drag forces, calculated using Morison’s equation and the linear small amplitude wave theory, were in good agreement with the results from model tests conducted in a wave making tank. Drag forces were negligible compared with inertia forces. Also, wave forces showed linear variation with the changing wave heights. It was revealed that the linear wave theory and Morison’s equation can give a simple and useful solution for the prediction of wave forces in the initial design stage of a submerged floating railway.

A numerical method to investigate the non-linear motion charact eristics of a TLP is established. A time domain simulation that includes the memory effect using the convolution integral is used to consider the transient effect of TLP motion. The hydrodyn amic coefficients and wave force are calculated using a potential flow model based on the HOBEM(higher order boundary element method). The viscous d rag force acting on the platform and tendons is also considered by using Morison ’s drag. The results of the present numerical method are compar ed with experimental data. The focus is the nonlinear effect due to the viscous drag force on the TLP motion. The ringing, springing, and drift motion are due to the drag force based on Morison's formula. 1. 서 론 TLP(Tension leg platform)는 텐던(Tendon)과 반잠수식 형태의 플랫폼으로 구성되며, 선장력(Pretension)을 갖는 텐던에 의해 수직면 운동의 공진주기를 파주파수영역에서 벗어나도록 하는 개념의 해양구조물이다. 우수한 수직면 운동성능으로 인하여 멕시코만 지역 혹은 Dry tree가 사용되는 지역에 주로 운영되어 왔으며, 최근에는 해상풍력 연구가 연안에서 깊은 수심으로 이동함에 따라 TLP형태의 구조물을 이용하는 사례가 늘어나고 있다. TLP형태의 구조물은 텐던이 갖는 강한 강성 때문에 고주파수 공진 운동응답인 링잉(Ringing) 혹은 스프링잉(Springing) 현상이 발생되며, 이 현상은 텐던의 피로도에 심각한 영향을 미친다. 이로 인해 고주파수 운동응답은 TLP 설계시 반드시 고려되어야 하는 중요한 요소이다.TLP의 거동에 관한 실험은 주로 고주파수 운동에 초점을 두고 이루어졌으며, 주요 연구는 다음과 같다. Stansberg et al.(1995)은 다양한 모양의 원형 실린더에 대한 고주파수 힘을 측정하였으며, 링잉현상에서 3차 조화 성분이 지배적으로 나타난다는 점을 지적하였다. Huse and Stansberg(1995)은 스프링잉 현상은 링잉 현상보다 비교적 낮은 해상상태에서 발생하며 파고의 제곱에 지배적인 점을 지적한 바 있다 .실린더 형태의 구조물에 작용하는 표류력을 계산하기 위해 많은 연구가 이루어졌으며, 주요 연구는 다음과 같다. Pijfer and Brink(1977)은 무한수심에서 파와 조류가 동시에 작용할 때, 반잠수식 시추선에 작용하는 표류력을 계산하였다. 이 계산 모델에서는 모리슨 식으로 단위플랫폼에 작용하는 동유체력을 적분하여 계산하고, 정수중의 조류력을 소거하였다. Hong(1985)은 이 모델508

This paper presents the results of an experimental and numerical study on the towing characteristics of a barge. A series of model tests were carried out at the Ocean Engineering Basin of KRISO. A model with a 1:50 scale ratio was constructed out of wood. First, force coefficient tests were performed in order to obtain the surge, sway, and yaw force coefficients of the barge. The focus was the effect of skeg on the force coefficients. The stability parameter was calculated from the force coefficients. Next, towing tests in calm sea were carried out with different towline lengths and towing speeds. The trajectories of the barge and the towline tensions were measured during the tests. The measured trajectories were compared with numerical simulation results using a cross-f low model. The towing stability of the barge in a calm sea is discussed in detail.

The purpose of this study was to compare the bone formation of autogenous tooth ash treated with different temperatures.Heat treatment was rendered by powder after extraction of teeth from dogs. The bony defects were made at iliac and resorbable blast medium surfaced implant placement and bone graft was performed; no bone graft group (control group), low heat-treated tooth ash group (group 1), high heat-treated tooth ash group (group 2). Right side had healing periods of 12 weeks, and the left side had 6 weeks. Histomorphometrical analysis was performed at 12 weeks.The control group had poor bone formation and showed large loose connective tissue. Group 1 displayed good healing and bone formation. Group 2 showed higher rate of bone formation than group 1 and the control group. The high heat-treated tooth ash group showed a statistically significant increase in the rate of bone formation in the early stage.The heat-treated autogenous tooth ash powder showed excellent new bone formation. The temperature of heat treatment is an important factor in new bone formation. The high heat treatment was the optimal treatment method for making tooth ash than the low heat treatment.

This paper compares the dynamic coupled behavior of floating structure and mooring system in time domain using two numerical methods for the mooring lines such as the linear spring method and the nonlinear FEM (Finite Element Method). In the linear spring method, hydrodynamic coefficients and forces on the floating body are calculated using BEM (Boundary Element Method) and the time domain equation is derived using convolution. The coupled solution is obtained by simply adding the pre-determined spring constants of the mooring lines into the floating body equation. In FEM, the minimum energy principle is applied to formulate the nonlinear dynamic equation of the mooring system with a discrete numerical model. The ground contact model and Morison formula for drag forces are also included in the formulation. The coupled solution is obtained by iteratively solving the floating body equation and the FEM equation of the mooring system. Two example structures such as weathervane ship and semi-submersible structure are analyzed using linear spring and nonlinear FEM methods and the difference of those two methods are presented. By analyzing the cases with or without surge-pitch or sway-roll coupling stiffness of mooring lines in the linear spring method, the effect of coupling stiffness of the mooring system is also discussed.

The death rate of liver cancer in Korea has been reported as one of the highest in the world. This study was conducted to investigate geographical variations of liver cancer mortality in Korea in order to obtain insight into possible environmental factors related to liver cancer.The sex-specific standardized mortality ratios (SMRs) of liver cancer were calculated for 168 basic administrative units in Korea based upon the vital statistics for the seven years 1992 to 1998, as well as the sex- and age-specific population of each area for 1995. The SMRs were classified into six categories and depicted on a map for each sex.The southern provinces showed clearly higher mortality rates as compared to the rest of the country in both males and females. Looking at the maps in detail, there was a geographical variation even within the southern provinces. The areas around large rivers, some costal areas, and costal islands showed a high mortality rate. Even in the middle and northern provinces, the eastern costal areas showed relatively higher mortality rates as compared to inland areas. Conversely, some southern areas known for low levels of pollution showed relatively lower mortality rates.This finding suggests a possible relationship between liver cancer and water-related foods from polluted rivers or seas. Further studies should be performed in order to clarify which factors cause this geographical variation.

The second-order motion characteristics of a semi-submersible are investigated in regular waves. A higher-order boundary element method in a frequency domain and a finite element method in a time-domain were applied to the numerical analysis of the nonlinear hydrodynamic force and motion characteristics of semi-submersibles in view point of potential flow. Various aspects of nonlinear effects on the heave and roll of a semi-submersible were numerically investigated and some selected cases were compared with the model test data.

An outbreak of occupational methanol poisoning occurred in small-scale, third-tier factories of large-scale smartphone manufacturers in the Republic of Korea in 2016. To investigate the working environment and the health effects of methanol exposure among co-workers in the methanol poisoning cases, we performed a cross-sectional study on 155 workers at five aluminum Computerized Numerical Control (CNC) cutting factories. Gas chromatography measured air and urinary methanol concentration. In the medical examination, symptom surveys, ophthalmological examinations, and neurobehavioral tests were done. Multiple logistic regression analyses controlling for age and sex were conducted to reveal the association of employment duration with symptoms. Air concentrations of methanol in factory A and E ranged from 228.5 to 2220.0 ppm. Mean urinary methanol concentrations of the workers in each factory were from 3.5 mg/L up to 91.2 mg/L. The odds ratios for symptoms of deteriorating vision and central nervous system (CNS) increased according to the employment duration after adjusting for age and sex. Four cases with an injured optic nerve and two cases with decreased neurobehavioral function were founded among co-workers of the victims. This study showed that the methanol exposure under poor environmental control not only produces eye and CNS symptoms but also affects neurobehavioral function and the optic nerve. The role of subcontracting production and dispatched work under poor environmental control was discussed.

State-of-the-art cluster-based data centers consisting of three tiers (Web server, application server, and database server) are being used to host complex Web services such as e-commerce applications. The application server handles dynamic and sensitive Web contents that need protection from eavesdropping, tampering, and forgery. Although the secure sockets layer (SSL) is the most popular protocol to provide a secure channel between a client and a cluster-based network server, its high overhead degrades the server performance considerably and, thus, affects the server scalability. Therefore, improving the performance of SSL-enabled network servers is critical for designing scalable and high-performance data centers. In this paper, we examine the impact of SSL offering and SSL-session-aware distribution in cluster-based network servers. We propose a back-end forwarding scheme, called ssl_with_bf, that employs a low-overhead user-level communication mechanism like virtual interface architecture (VIA) to achieve a good load balance among server nodes. We compare three distribution models for network servers, round robin (RR), ssl_with_session, and ssl_with_bf, through simulation. The experimental results with 16-node and 32-node cluster configurations show that, although the session reuse of ssl_with_session is critical to improve the performance of application servers, the proposed back-end forwarding scheme can further enhance the performance due to better load balancing. The ssl_with_bf scheme can minimize the average latency by about 40 percent and improve throughput across a variety of workloads.

International Maritime Organization (IMO) is planning to include the Alternative Assessment of the Weather Criterion in the new Intact Stability (IS) Code to be revised. In this study, the procedure of the model test in the Interim Guidelines was reviewed by carrying out the model test and analyzing the test results. For this purpose, RO/RO passenger ship whose ratios of breadth to draft and the height of weight to draft were above 3.5 and above 0.6 respectively was selected as a test ship. Drifting test and motion test in regular waves were performed to estimate the hydrodynamic heeling lever and roll-back angle. Motion tests in waves were carried out in the three wave steepness conditions to measure roll-back angle and examine the feasibility of so called, the Three-step method. Using the test data, satisfaction of the Weather Criterion was assessed for the test ship by using the alternative method and compared with the current method.

Very Large Floating Structure(VLFS) is regarded as one of promising candidates for the future utilization of ocean space. VLFS has the merits of small environmental effect. short construction term, easiness for extension and removal. It is well known that hydroelastic response is one of major design concerns of such a huge structure. Most of studies on the hydroelastic analysis of VLFS assumed uniform mass and bending stiffness. In case of a floating hotel where noticeable change of mass and stiffness at the hotel part is expected. it is necessary to investigate the effect of nonuniform mass and bending stiffness on the hydroelastic response. A model test of a pontoon type VLFS with nonuniform bending stiffness carried out for performance evaluation of a floating marina-hotel-convention center is described in this paper. Through investigation of model test results and comparison with numerical analysis using eigenfunction method, effect of the variation of bending stiffness is discussed.

Leakage current characteristics have been investigated for nitride-based InGaN light-emitting diodes (LEDs) with different levels of Si-doping conditions applied to the n-type InGaN/GaN layer. The tested LED samples had an emission wavelength of 445 nm. Based on the analysis of temperature-dependent characteristics measurements, the reverse leakage current, IR, was predominantly influenced by the lowering of Poole-Frenkel (PF) barrier for low electric field ( ;8 × 107 V/cm), phonon-assisted tunneling (PAT) dominates the IR mechanism. The IR is influenced by the Si-doping density of InGaN/GaN layer that may be present near the end of depletion regions of tested samples.

We fabricated and characterized an integrated optical mirror in a polymeric waveguide. A parabola-shaped cavity is etched in fluorinated polyimide using oxygen reactive ion etching. The vertically etched sidewall of the planar waveguide works as a highly reflecting total-internal-reflection mirror, which collimates a diverging beam from its focus. The estimated mirror insertion loss of the demonstrated device is 2.4 dB or less.

A thin-film polymeric waveguide beam deflector was fabricated and demonstrated. The three-layer planar waveguide was composed of UV15 as the top cladding layer, a polyimide as the core layer, and SiO/sub 2/ as the bottom cladding layer on a silicon substrate. A gold layer was deposited on the top of the waveguide by e-beam deposition and then patterned into a prism-array as the heating electrode by photolithography. Beam deflection was acquired by passing the beam through the waveguide underneath the prism array. The beam deflection angle showed the expected quadratic dependence upon the applied voltage. A maximum acquired beam deflection angle of 2.5/spl deg/ was derived at an applied voltage of 8 V. Eight resolvable spots were observed, which made possible the feasibility of a 1/spl times/8 optical switch.

Materializing NEMS devices incorporating nonlinear dynamics is of fundamental importance in the field of small-scale mechanics and general science. Among these, parametric amplification draws considerable attention due to its unique characteristic. In this paper, we introduce novel designs for mechanically pumped parametric resonators in which torsional pumping springs are linked. The proposed parametric resonators can increase signal amplitude by matching resonances in a cantilever and beam. Amplitudes of resonators increase when resonances of cantilevers are amplified by torsional pumping from linked beams. In an attempt to transmit pure torsion (not displacement), zero-displacement points method is suggested, and the analytical prediction results are further verified by the corresponding simulation results obtained from COMSOL Multiphysics® . The π-shape resonators are fabricated by surface nano-machining process, and the horizontal dimensions of fabricated beams and cantilever are 31.6 um and 8 um, respectively. By using magnetomotive method, resonance frequencies are measured. Finally frequency matching is performed by DC tuning. When 54 V is applied, fdrive and fpump increase 0.78% and 0.16%, and the frequencies are exactly matched as 4.463 MHz.Copyright © 2010 by ASME

We numerically study surface-plasmon (SP) mediated semiconductor light-emitting diodes (LEDs) and show that mediation of SPs can be useful for high power LEDs in their modulation speeds and directionalities. It has been reported that SPs can drastically enhance internal quantum efficiencies and speeds of InGaN quantum-well (QW) LEDs by letting them dominate spontaneous emission (SE) processes. Many experimental and theoretical studies have been conducted in this context but most of the works have dealt SE into SPs and light extraction from excited SPs separately. In particular, there is no theoretical analysis, to our knowledge, which simultaneously considers SE into SPs on a textured metal surface along with its extraction to outside radiation. In this presentation, we numerically study InGaN QW LEDs which consist of 1-D metallic gratings on a p-contact electrode and an adjacent single QW emitting green light by using finite-difference time-domain (FDTD) method. We focus on the case where the first order diffraction of SPs produces lightwaves propagating along the surface-normal direction. SP band-edge effect on SE rate, extraction of SPs into internal-radiation, and angular directionality of final outside-radiation are analyzed. Practical enhancement of LED performances are discussed on the basis of the simulation results.

We propose a unique method determining an upper limit of extraction efficiency of the surface plasmon-polaritons (SPPs), E(SP), which are highly confined on a corrugated metal surface. The method is based on measurement of the spectral bandwidth of a grating-induced absorption spectrum as a function of metal dielectric constant. After finding the fact that E(SP) exhibits an extremely linear relationship with the collision frequency Gamma of metal over a SPP band below the surface plasmon frequency, an upper limit of E(SP) can be determined by an asymptotic estimation as Gamma--0 for total decay rates of the confined SPPs. Our method based on the bandwidth measurement is inherently free from the ambiguity and underestimation difficulties pertaining to the previous prism-coupling approaches for E(SP) estimation. It will also be quite applicable for evaluating SPP-mediated light-emitting diodes (LEDs) of which total external efficiency is dominantly restricted by the upper limit of E(SP). Especially for the case when SPP excitation probability approaches unity, the proposed method would excellently figure out the maximum realizable external efficiency of SPP-mediated LEDs.

Trichromatic LED backlights render higher color gamut and panel transmittance to liquid crystal displays (LCDs) than yellow phosphor-converted white LED backlights can possibly do at their best. In realization, however, several technical challenges arise, such as colour shift due to the ambient temperature change, decrease in brightness at elevated temperature, an enlarged dead zone for colour mixing, minimizing the total number of chips and so on. In this work, we designed and demonstrated a low-cost driving circuit that stabilizes brightness and colour coordinates of trichromatic LED backlights using a thermistor as a temperature compensating element. By applying the temperature compensation, the amounts of the brightness and colour shift were reduced to 54% and 51% of the uncompensated cases, respectively.

Purpose: This study was designed to determine the factors affecting completion of critical pathway for elective gastrectomy. Methods: Since 2008, a critical pathway has been applied for elective gastrectomy at Chosun University Hospital. We retrospectively analyzed 252 patients who underwent elective gastrectomies from January 2009 to April 2013. The completion rate was determined, and risk factors for patient dropout were examined. Results: The completion rate of the critical pathway was 45.6% (115/252). Mean length of stay was 11.7 ± 8.6 days (8?59 days). Readmission rates were 4.4% (11/252). Causes of failure for clinical pathway were systemic complications (21/137, 15.3%), intra-abdominal complications (44/137, 32.8%), patient factors (41/137, 29.9%), and wound complications (30/137, 21.9%). There were no significant differences between the two groups in age, sex, American Society of Anesthesiologists (ASA) score, operation time, readmission, and underlying disease (P > 0.05). Body mass index (P = 0.008) and pathologic stage (P = 0.001) were significantly different between the two groups. In multivariate analysis, the conventional approach (odds ratio, 2.0), and total gastrectomy (odds ratio, 5.3) were determined to be independent risk factors to drop the critical pathway. But there were no significant differences between total and distal gastrectomy groups in age, gender, underlying diseases, ASA score, readmission, operation time, and cause of dropout (P > 0.05). Conclusion: We concluded that total gastrectomy may not be suitable for the critical pathway. We suggest that the critical pathway for elective distal gastrectomy is divided 2 subgroups, according to the surgical approach.

We developed a low cost small port-count ROADM(Reconfigurable Optical Add-Drop Multiplexer) using simple MEMS (Micro Electro-Mechanical System) type 2times2 OSWs (Optical Switches) and VOAs (variable optical attenuators). The ROADM module consisting of components all developed in-house performed fast and reliable add/drop function with channel equalisation. The output power flatness was controlled to less than 0.5 dB over four CWDM channels

Ultra-compact silicon-photonic-crystal-waveguide-based thermo-optic and electro-optical Mach-Zehnder interferometers have been proposed and fabricated. Thermal and electrical simulations and optical characterizations have been performed. Experimental results were in good agreement with the theoretical predictions.

Knowledge creation by technology-based enterprises is increasingly becoming internationalized. In numerous technology-based companies attempt to position their R&D centers in places where markets are rapidly growing or new technologies are actively developed. Then what are key factors in R&D internationalization of developing countries? How do those factors result in such diversified patterns of internationalization? Are they, in fact, related to the rapid growth of IT technologies in Korea? One of objectives of this study is to define the nature of Korea's R&D internationalization, which has been making rapid progress recently. With this objective, we examined the cases of research projects conducted jointly with major international R&D institutes, and inducement of foreign R&D centers, analyzing the pattern of cooperative activities. The targets of case study were international joint research projects conducted during the period from 1998 through 2000, under sponsorship of MIC (Ministry of Information and Communication). We also conducted survey on motives of multinational corporations which have recently established R&D centers in Korea. For the research, we made reference to documents relating R&D activities in IT industry published by government agencies and research administration bodies, as well as relevant articles. Due to the nature of R&D activities in IT industry, which limits the usefulness of documents in identifying their distinctive features, we also interviewed with key researchers engaging in the projects. Motives, objectives and issues were surveyed through structural interviews, and industrial, technological features were identified through non-structural interviews

Trichromatic LED backlights render higher color gamut and panel transmittance to the liquid crystal displays (LCDs) than yellow phosphor-converted white LED backlights can possibly do at their best. In realization, however, several technical challenges arise, such as color mixing, minimizing the total number of chips, and maintaining the color balance. We designed and demonstrated a backlight unit for 2.2 inch TFT LCD using two RGB 3-chip LEDs to assess the feasibility and the technical hurdles to overcome. The average brightness of the backlight is 2509cd/m 2 at the input power of 200mW. The power efficiency is lower than but comparable to commercially available white LED backlights. The color gamut of the LC panel is increased from 53% to 78% when its conventional white LED backlight is replaced by the trichromatic LED backlight. Panel transmittance is expected to be enhanced as well by about 8%. The ambient temperature change was found to be the most significant cause of the color shift of the trichromatic LED backlight. The forward bias voltage can be used in the feedback, since it changes linearly with temperature.

Improving the performance of Web servers has become a critical issue to handle the increasing demand on various network-based services. In this context, we exploit the local memory of programmable network interface cards (NICs) to improve the performance of cluster-based Web servers, which are increasingly used in designing Web server platforms. We use the NIC memory for caching recently accessed data blocks to improve server performance. We have implemented a prototype of the proposed NIC caching mechanism for a distributed Web server, based on PRESS (Carrera et al., 2002), on an 8-node, Myrinet-connected Linux cluster. Measurements with several server workloads show that NIC caching can enhance throughput by up to 27% compared to the original PRESS Web server without NIC caching, by minimizing the DMA and PCI bus overhead

Although the secure sockets layer (SSL) is the most popular protocol to provide a secure channel between a client and a cluster-based network server, its high overhead degrades the server performance considerably, and thus, affects the server scalability. Therefore, improving the performance of SSL-enabled network servers is critical for designing scalable and high performance data centers. In this paper, we examine the impact of SSL offering and SSL-session aware distribution in cluster-based network servers. We propose a backend forwarding scheme, called ssl_with_bf that employs a low-overhead user-level communication mechanism like VIA to achieve good load balance among server nodes. We compare three distribution models for network servers: round robin (RR), ssl_with_session and ssl_with_bf through simulation. The experimental results with 16-node and 32-node cluster configurations show that while session reuse of ss_with_session is critical to improve the performance of application servers, the proposed backend forwarding scheme can further enhance the performance due to better load balancing. The ssl_with_bf scheme can minimize average latency by about 40% and improve throughput across a variety of workloads

We present a novel privacy filter film with transparent micro-cuboid arrays. The privacy filter film, which does not include any opaque materials, rarely affects the normal transparency, whereas it obscures personal information by distorting paths of oblique light rays. The effects of the cuboid size and a gap between the privacy filter and a display are analyzed using a ray-tracing program. The analysis is consistent with the experimental results carried out using the poly-dimethylsiloxane (PDMS) micro-cuboid (100 mu m x 100 mu m x 200 mu m) arrays, which are fabricated by lithography and transfer molding. (C) 2014 Optical Society of America

We experimentally demonstrate the 1.5-fold enhancement of the electroluminescence (EL) of surface-plasmon (SP)-mediated green LEDs. On the p-clad surface of InGaN/GaN multi-quantum well LEDs, a 2-dimensional, second-order grating structure is textured and coated with an Ag electrode. With this setup, a larger EL enhancement factor is obtained at a higher injected current, which suggests that SP-LEDs can be a possible solution to efficiency droop, which is one of the main problems in developing high-power LEDs. Details regarding the implementation of our device are discussed.

Purpose: The purpose of this study was to identify the changes in body weight, anxiety, depression, and quality of life in patients during a one month period following a radical gastrectomy. Methods: Data were collected from 30 patients with gastric cancer from July 2, 2012 through December 31, 2012, at C University Hospital, Gwangju, South Korea. The body weight, anxiety, depression, and quality of life (QoL) of the patients were measured using structured questionnaires the day before surgery, day 7 postoperative, and 1month postoperative. Results: There were significant changes in the average body weight and the general health status/QoL, the functionality, and the symptoms of general QoL, and the functionality and the symptoms of specific QoL during the postoperative 1month period (χ 2 =52.47-7.68, p

We fabricated and demonstrated a beam deflector implemented in an electro-optic polymer planar waveguide. An array of prism- shaped electrodes formed on the top of the waveguide induces selective refractive index change in the core polymer layer, which results in the tilt of the propagation direction of the guided beam. Waveguide beam deflectors have potential applications in the emerging photonics technologies such as optical storage systems, optical phased array antenna, and optical switching. The deflection sensitivity of 28 mrad/kV, and the maximum deflection angle of +/- 8.4 mrad at +/- 300 V were obtained for this first demonstrated device.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In this paper, we demonstrate a thin-film polymeric waveguide beam deflector using a new device concept, an electrode of prism-array pattern on top of a three-layer planar waveguide. The three-layer planar waveguide was composed of UV15 as the top cladding layer, a polyimide as the core layer, and SiO 2 as the bottom cladding layer on a silicon substrate. A gold layer was deposited on the top of the waveguide by e-beam deposition and then patterned into a prism-array as the heating electrode by photolithography.

A novel approach for laser beam deflection using the thermal optic prism array in a polymeric planar waveguide is developed. This approach is based on the different thermo- optic properties between polymer and silica, the two optical materials employed for the guided wave beam deflector. A waveguide structure with the core layer composed of inversely positioned polymer and silica triangles forming a polymer/silica prism array has been fabricated. Through electrical heating, a temperature change results in an index difference between the two optical materials and creates an optical prism structure in the polymer/silica planar waveguide. A beam deflection of 5.4 degree was observed under a temperature change of 60 degrees C in the fabricated prism array. The sensitivity of the device is 0.09 degrees/degrees C. A maximal number of resolvable spots of 8 was achieved at a low driving power from the thermo-optic prism array structure. The accuracy of beam deflection approaches 16 micro-radian. The device fabricated has a thickness of 5 microns, a prism aperture width of 600 microns, and a device length of 7 mm. Optimal design to maximize the deflection angle and the number of resolvable spots has been evaluated.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A beam deflector device has been demonstrated that used thin-film electro-optical polymeric waveguide. Prism cascade was fabricated within a planar waveguide. We report the detail of the design and fabrication of new polymer material beam deflector to operate at 1.3 micrometers .

A study was carried out to evaluate: (a) the value of a cumulative exposure estimate (CEE) calculated from limited information on air concentration; and (b) whether chronic exposure to mixed organic solvents at a shoe manufacturing factory has induced neurobehavioral changes. The Neurobehavioral Core Test Battery was administered to 40 female workers from a shoe manufacturing factory and 28 housekeepers as referents. The airborne concentrations of the solvents as a mixture were 0.46-0.71 at the frame making process and 1.83-2.39 at the adhesive process. Performance was analyzed by three exposure indices: current department, exposure duration, and CEE. The Santa Ana Dexterity test showed statistically significant differences only in CEE. In particular, the group with higher exposures had a significantly poorer performance than the reference group, on preferred hand trials. The results suggested that CEE appeared to be a better indicator of mixed organic solvents exposure, and neurobehavioral changes were associated with CEE over 10 years.

Currently it is very popular to use off-axis illumination technique for higher resolution with wider depth of focus. However there are several problems in the technique, one of which is deterioration of image quality induced by the non- uniform effective source distribution. If the intensity distribution on the illumination aperture lacks of spatial symmetry, each diffraction order beam impinging on the wafer surface has angularly asymmetric distribution. This makes the optical system have pattern size dependent telecentricity error. For a simple line or grouped lines it gives rise to only the pattern displacement with defocus which can hardly be detected unless there are any reference. But the periodic island type patterns which have discrete features and multiple pitch components in one direction can be bent and deformed asymmetrically with defocus. Asymmetric imaging for island type patterns gives rise to also the pattern CD asymmetry with defocus. We present schematic explanation of the effects of non-uniform effective source and the simulation result. We also investigated the phenomena in a high density DRAM cell active layer of 460 nm minimum pitch and characterized it by various approach.

Diverticular disease of the colon is a common disease, and its incidence is increasing gradually. A giant colonic diverticulum (GCD) is a rare entity and is defined as a diverticulum greater than 4 cm in size. It mainly arises from the sigmoid colon, and possible etiology is a ball-valve mechanism permitting progressive enlargement. A plain abdominal X-ray can be helpful to make a diagnosis initially, and a barium enema and abdominal computed tomography may confirm the diagnosis. Surgical intervention is a definite treatment for a GCD. We report a case of an ascending GCD presenting with intussusception in a young adult.

The location of the sigmoid colon varies within the abdominal cavity, but its mesocolon is fixed to the left side. Right side fixation of the sigmoid colon is a very rare congenital positional anomaly. In addition, it has been reported that hepatocolic fistula is also a very rare disease that may present lower gastrointestinal bleeding. Here, the authors describe a case of a 71-year-old man who underwent surgery for hepato-sigmoidocolic fistula complicated by hepatocellular carcinoma and the right side fixation of the sigmoid colon.

Inferior alveolar nerve block obtained maximum anesthetic effect using a small dose of local anesthetic agent, which also has low a complication incidence. Complications of an inferior alveolar nerve block include direct nerve damage, bleeding, trismus, temporary facial nerve palsy, and etc. Among them, the major iatrogenic complication is dental needle fracture. A fragment that disappears into the soft tissue would be hard to remove, giving rise to a legal problem. A 31-year-old woman was referred for the removal of a broken needle, following an inferior alveolar nerve block. Management involved the removal of the needle under local anesthesia with pre- and peri-operative computed tomography scans.

In this paper, we have systematically investigated the effects of NH 3 nitridation of N 2 O oxides and subsequent reoxidation on MOSFET performance and reliability. Results indicate that as compared to oxides grown in pure O 2 or N 2 O ambient, NH 3 nitridation of N 2 O oxides (with or without reoxidation) slightly degrades the electron mobility ((mu) e,eff ) of n-MOSFETs at low V G , but enhances (mu) e,eff significantly at high V G . For p-MOSFETs, nitridation of N 2 O oxides degrades hole mobility ((mu) h,eff ) slightly for all V G . In addition, reoxidation of NH 3 -nitrided N 2 O oxides is required to improve the hot-carrier immunity for both n- and p-MOSFETs under various static bias configurations, with N 2 O-reoxidation being considerable more effective than O 2 -reoxidation. It is demonstrated that N 2 O reoxidation is capable of completely removing nitridation- induced electron traps, resulting in devices with hot-carrier reliability comparable to N 2 O oxide devices. The superior reliability characteristics together with demonstrated improved resistance to boron penetration make N 2 O-reoxidized NH 3 -nitrided N 2 O oxides a very promising gate dielectric candidate for deep- submicrometer dual-gate CMOS applications.