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Background There remain concerns about the safety and functional benefit of laparoscopic pylorus-preserving gastrectomy (LPPG) compared with laparoscopic distal gastrectomy (LDG). This study evaluated short-term outcomes of a randomized clinical trial (RCT) comparing LPPG with LDG for gastric cancer. Methods The Korean Laparoendoscopic Gastrointestinal Surgery Study (KLASS)-04 trial was an investigator-initiated, open-label, parallel-assigned, superiority, multicentre RCT in Korea. Patients with cT1N0M0 cancer located in the middle third of the stomach at least 5 cm from the pylorus were randomized to undergo LPPG or LDG. Participants, care givers and those assessing the outcomes were not blinded to group assignment. Outcomes were 30-day postoperative morbidity rate and death at 90 days. Results Some 256 patients from nine institutions were randomized (LPPG 129 patients, LDG 127 patients) between July 2015 and July 2017 and outcomes for 253 patients were analysed. Postoperative complications within 30 days were seen in 19.3 and 15.5 per cent in the LPPG and LDG groups respectively (P = 0·419). Postoperative pyloric stenosis was observed in nine (7.2 per cent) and two (1·5 per cent) patients in the LPPG and LDG groups (P = 0·026) respectively. In multivariable analysis higher BMI was a risk factor for postoperative complications (odds ratio 1·17, 95 per cent c.i. 1·04 to 1·32; P = 0·011). Death at 90 days was zero in both groups. Conclusion Postoperative complications and mortality was comparable in patients undergoing LPPG and LDG. Registration number: NCT02595086 (http://www.clinicaltrials.gov).

A multi-wavelength channel distributed feedback laser diode array (DFB-LDA) for the low-cost and low-power consumption applications of WDM-based datacentre networks is reported. The gain spectrum and lasing wavelength of each channel are controlled by using selective area growth and E-beam lithography techniques, respectively. To reduce the operation current and parasitic capacitance of the proposed array, an etched mesa buried hetero-structure (EMBH) is introduced. From this study, it was found that an eight-channel 300 μm long λ/4-shifted DFB-LDA has a threshold current of 10 ± 1.5 mA and a side mode suppression ratio of over 50 dB at a current of 50 mA for all channels. A transmission test for this LDA showed a clear eye opening with a dynamic extinction ratio of over 4.5 dB at 10 Gb/s after a 2 km transmission.

We have studied the effect of design parameters on the performance of non-biased optical bistable (NOB) devices fabricated with non-resonant multiple quantum wells nipi-diode structures. This device made of extremely shallow quantum wells as intrinsic regions allows both a large low-field electroabsorption change and exciton ionization, and consequently, ensures both large electric field swing and strong light absorption without external bias voltage. By optimizing stack pairs of non-resonant nipi-structures, the performance of the NOB device was significantly enhanced with a large signal contrast ratio, low heat power dissipation, and low drive voltage, while maintaining low switching energy, high signal difference, and layout simplification.

In this work, we describe the successful demonstration of continuous wave (CW) operation of all monolithic air-gap 1.55 /spl mu/m VCSELs with tunnel junction grown by MOCVD.

In acupuncture practice of animals, preanesthetics sometimes are needed. The purpose of this study was to select the ideal chemical restraint at acupuncture for gastric motility. Nine healthy mixed breed dogs weighed 10-21 kg and aged 1-3 years old were used in this study. Two EMG surface electrodes were placed between the seromuscular and the mucosal layer of pylorus. Twenty minutes after feeding normal gastric motility was recorded for 60 minutes using physiograph (Narco-Biosystem). Then preanesthetic treated-gastric motility was observed for 30 minutes. Preanesthetics used were xylazine, diazepam, and acepromazine. Acupuncture needles were inserted to BL-21 (Wei-Yu) acupoint, and then changes of gastric motility were recorded for 60 minutes. The gastric motility following xylazine administration (1 mg/kg, IV) was markedly decreased. BL-21 (Wei-Yu) acupoints stimulation did not alter xylazine-induced depression of gastric motility. The diazepam (1 mg/kg IV) treated-gastric motility was increased mildly 20 minutes after drug administration. BL-21 (Wei-Yu) acupoint stimulation after diazepam administration enhanced gastric motility significantly. The gastric motility following acepromazine (0.3 mg/kg, IM) administration was not changed compared with normal gastric motility. Application of traditional acupuncture at BL-21 (Wei-Yu) significantly increased the gastric motility. Based on these results, acepromazine and diazepam could be acceptable chemical restraints for acupuncture therapy of gastric motility, but xylazine couldn't be.

In order to examine the use of a compliant cantilever beam structure as a contact scheme for a multichip interconnection system (MIS), multilayer (metals and SiO/sub 2/) cantilever beams were fabricated utilizing standard IC processing technologies and micromachining of silicon. The mechanical behavior and electrical characteristics of the beams were investigated to establish their optimum dimensions for use in the MIS. The number of inputs/outputs which can be achieved by this structure is approximately 1000 per 1-cm/sup 2/ chip site. Au-to-Au contact resistance measurements, as a function of applied force, were carried out employing the Nanoindenter. The contact resistance data and the results from calculations on the maximum deflection and resisting force of these beams suggest that, through proper design, it is possible to achieve simultaneously acceptable and stable resistance values ( >

It is shown that nonbiased optical bistability in an extremely shallow quantum well symmetric self-electro-optic effect device can be significantly improved by using an impedance-mismatched asymmetric Fabry-Perot scheme. The device in a simple layout shows nonbiased bistability width, ΔR, contrast, and Vop of ~53%, 17%, 3.7:1, and 0.9 V, respectively.

Summary form only. We explored all-monolithic VCSELs employing InP lattice matched InAlGaAs/InAlAs system and a 2/spl lambda/-thick periodic gain active region. We discuss further results on the electrical pulsed operation of 1.55 /spl mu/m all-monolithic, air-post index guided VCSELs at room temperature.

A co-operative study was conducted to determine the clinical characteristics of patients with moyamoya disease who were diagnosed and treated at neurosurgical institutes in Korea before 1995. Twenty-six hospitals contributed 505 cases and among them, the clinical characteristics of 334 patients with definite moyamoya disease were evaluated. The number of patients began to increase from the late 1980s, and after that approximately 20 patients were treated each year. There were two age peaks: from six to 15 and from 31 to 40 years of age. Haemorrhagic manifestations occurred in approximately 43% of the patients. The major clinical manifestations were haemorrhage in adults (62.4%) and ischaemia in children (61.2%). Overall 54.5% of the patients experienced decreased consciousness levels, mainly due to intracranial haemorrhage or cerebral infarction. In the patients with ischemic manifestations, the adult patients were more likely to have cerebral infarction than the pediatric patients (80% vs. 39%) and the pediatric patients were more likely to have TIA (61% vs. 25%). Thirty eight percent of the patients underwent bypass surgery and 53% of these procedures were performed bilaterally. Treatment policies, including indications for bypass surgery and commonly used drugs, were somewhat different according to the institution. Overall favorable outcome was 73%, and the most significant factor affecting poor outcome was haemorrhagic manifestation. This article describes the characteristics of 334 patients with moyamoya disease, who were diagnosed and treated at neurosurgical institutes in Korea before 1995.

To achieve low operating voltage, fast switching time, and high ON/OFF contrast ratio, we learned that an extremely shallow multiple quantum well (ESQW) symmetric self electro-optic effect device (S-SEED) having an asymmetric Fabry-Perot (AFP) etalon structure, that we named AFP-ESQW S-SEED (AE-SEED), is effective as reported previously.1 In this paper we report experimental results and the analysis of the upper limit of the reading beam intensity.

The effects of exogenous surfactant (SF) replacement therapy associated with high frequency jet ventilation (HFJV) on blood gas changes, pulmonary and hemodynamic variables were studied in canine lavaged lungs. The lungs were lavaged repeatedly with physiological saline until PaO2 decreased to 100 mmHg under intravenous pentobarbital anesthesia with 100% oxygen. SF (50 mg.kg-1) in the experimental group (n = 12) and saline in the control group (n = 8) were administered to the trachea using HFJV with a duration of 10 min. HFJV was further continued for 1 hour to make surfactant distribute evenly. Then respiration was controlled by the conventional mechanical ventilator for 3 hrs. During the administration of SF (10 min). PaCO2 was not altered. In the surfactant group, PaO2 improved significantly (200 mmHg) at the end of HFJV and was maintained for the next 3 hrs at this level, but it did not improve in the saline group. Therefore, we suggest that HFJV can be used safely for the treatment of acute respiratory failure and is an effective method for the administration of the pulmonary surfactant into the alveoli.

The electroluminescence (EL) of an organic light-emitting diode specially fabricated with a pure thin dye layer 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) of 1-nm thickness inserted at the interface between N,N′-bis-(1-naphthl)-diphenyl-1,1′-biphenyl-4,4′-diamine and tris(8-quinolinolato) aluminum has been investigated. The EL behavior of this device changed dramatically at a driving voltage of about 12.25V, which has been ascribed to the breakage of the thin DCJTB layer. It is suggested that not only such thin layer of DCJTB can transport electrons and holes, but also trap them. A comparison of the EL performance with four other devices confirms this mechanism. Therefore, the high efficiency and long life of the dye doped Alq devices are attributed to the hole and electron trapping effect and the high photoluminescence efficiency of the dye.

We have constructed a non‐biased all‐optical bistable device using electroabsorption in multiple quantum wells (MQWs). The device is made of a serial connection of two identical double p‐i‐n (p‐i‐n‐i‐p) diode structures within asymmetric Fabry–Perot (AFP) cavity. This scheme ensures both large internal electric field swing and full exploitation of the light intensity. From the measurement of the diode properties, the non‐biased bistability parameters—reflection change of 19%, contrast ratio of 17:1, and bistable loop width of 70%—were obtained.

A a 1.55 /spl mu/m InAlGaAs/InP vertical-cavity surface-emitting laser grown by metal-organic chemical vapour deposition is presented. Al/sub 2/O/sub 3//a-Si thin-film pairs and InAlGaAs/InAlAs epitaxial layers are used as a top mirror and a bottom-side output coupler, respectively. Direct modulation characteristics through singlemode fibre are reported at a speed of 2.5 Gbit/s.

A stepwise driving method has been successfully applied for AC power saving in data driver circuits of TFT-LCDs. For DC power saving, we have also proposed dual-VDD architecture for output buffers of data driver circuits. Experimental results show that over 75% of AC power and about 40% of DC power can be saved for 14.x-inch or larger size TFT-LCDs with XGA resolution. The proposed data driver can be realized with very small area-overhead.

A novel reactive ion etching process for the InAlGaAs material system lattice matched to InP using BCl3/Cl2/CH4/H2 mixtures is presented. The etching speed is ~ 700 A/min, which remains approximately the same for all InAlGaAs compositions. The smoothness and the anisotropy of the etched wall appear to be very good. The etching characteristics of InP and mask materials are also reported.

An unsteady, two-dimensional boundary-layer solution procedure is used to predict two different types of incompressible turbulent mean flows, the Blasius and Howarth flows, with superimposed time-dependent harmonic oscillations. A simple algebraic mixing length model that includes a minor modification for unsteadiness in the inner part of the boundary layer was used. Computed results for the two different mean flows over a wide range of unsteady conditions are presented and compared with measured data and other numerical solutions. The overall agreement of the present solutions with measurements is very good, although details of unsteady characteristics are not completely resolved due to shortcomings in the closure model.

A robust, time-marching Navier–Stokes solution procedure based on the explicit hopscotch method is presented for solution of steady, two-dimensional, transonic turbine cascade flows. The method is applied to the strong conservation form of the unsteady Navier–Stokes equations written in arbitrary curvilinear coordinates. Cascade flow solutions are obtained on an orthogonal, body-conforming “O” grid with the standard k–ε turbulence model. Computed results are presented and compared with experimental data.

In this paper a methodology for formulating kinematic constraint equations and equations of motion for constrained mechanical systems is presented. Constraint equations and transformation matrices are expressed in terms of Euler parameters. The kinematic velocity and acceleration equations, and the equations of motion are expressed in terms of physical angular velocity of the bodies. An algorithm for solving the constrained equations of motion using a constraint stabilization technique is reviewed. Significant reduction in computation time can be achieved with this formulation and the accompanying algorithm as compared with the method presented in Part 1.

An accurate and reliable solution procedure is presented for solving the two-dimensional, compressible, unsteady boundary layer equations. The procedure solves the governing equations in a coupled manner using a fully implicit finite-difference numerical algorithm. Several unsteady compressible and incompressible laminar flows are considered. Example results for two unsteady incompressible turbulent flows are also included. An algebraic mixing length closure model is used for the turbulent flow calculations. The computed results compare favorably with experimental data and available analytical/numerical solutions.

A viscous-inviscid interaction scheme has been developed for computing steady incompressible laminar and turbulent flows in two-dimensional duct expansions. The viscous flow solutions are obtained by solving the boundary-layer equations inversely in a coupled manner by a finite-difference scheme; the inviscid flow is computed by numerically solving the Laplace equation for streamfunction using an ADI finite-difference procedure. The viscous and inviscid solutions are matched iteratively along displacement surfaces. Details of the procedure are presented in the present paper (Part 1), along with example applications to separated flows. The results compare favorably with experimental data. Applications to turbulent flows over a rearward-facing step are described in a companion paper (Part 2).

A viscous-inviscid interaction calculation procedure is described for viscous flows containing separation bubbles based on an inverse finite-difference boundary layer method and a small disturbance Cauchy integral formulation for the inviscid flow. The viscous-inviscid matching procedure used appears to eliminate the need for smoothing or under-relaxation which is commonly required by other methods. Turbulence modeling for transitional separation bubbles is discussed and two empirically-based transition models are evaluated for bubble flows. Predictions for a laminar and a laminar-turbulent transitional bubble are presented. These predictions are compared with results from other prediction methods and with experimental measurements for the transitional bubble flow.

This paper presents useful and interesting identities between Euler parameters and their time derivatives. Using these identities, kinematic constraints and equations of motion for constrained mechanical systems are derived. These equations can be developed into a computer program to systematically generate all of the necessary equations to model mechanical systems. The compact form of these equations makes it possible to develop a general-purpose computer program for dynamic analysis of mechanical systems suitable for operation on small computers with limited memory space.

A finite-difference calculation method based on the boundary-layer equations is described for the prediction of laminar, developed channel flow undergoing a symmetric sudden expansion. The scheme requires only a fraction of the computational effort required for the numerical solution of the full Navier-Stokes equations that are usually employed for this flow. Predictions of the method compare very favorably with experimental data and solutions of the full Navier-Stokes equations.

The viscous-inviscid interaction numerical procedure described in Part 1 is used to predict steady, two-dimensional turbulent flow over a rearward-facing step. The accuracy of predictions is observed to be quite sensitive to the specification of length scale in the turbulence modeling. The best results are observed when the length scale is specified algebraically downstream of the step using parameters characteristic of the step geometry. Predictions of mean flow quantities and reattachment length are shown to be in generally good agreement with measurements obtained over a range of channel expansion ratios.

The survival time of HIV/AIDS patients in Korea has increased since HAART (highly active anti-retroviral therapy) was introduced. However, the occurrence of drug-resistant strains requires new anti-retroviral drugs, one of which, an integrase inhibitor (INI), was approved by the US Food and Drug Administration (FDA) in 2007. INIs have been used for therapy in many countries and are about to be employed in Korea. Therefore, it is important to identify basic mutant variants prior to the introduction of INIs in order to estimate their efficacy. To monitor potential drug-resistant INI mutations in Korean HIV/AIDS patients, the polymorphism of the int gene was investigated together with the pol gene using a genotypic assay for 75 randomly selected Korean HIV-1 patients newly diagnosed in 2007. The drug-resistant mutation sequences were analysed using the Stanford HIV DB and the International AIDS Society resistance testing-USA panel (IAS-USA). Seventy strains of Korean subtype B were compared with foreign subtype-B strains, and there were no significantly different variants of the int gene region in the study population. Major mutation sites in the integrase (E92Q, F121Y, G140A/S, Y143C/R, Q148H/R/K and N155H) were not detected, and only a few minor mutation sites (L74M, V151I, E157Q, V165I, I203M, S230N and D232N) were identified in 21 strains (28%). Resistance due to mutations in the pol gene was observed in a single strain (1.3%) resistant to protease inhibitors (PIs) and in four strains (5.3%) resistant to reverse transcriptase inhibitors (RTIs). In summary, this demonstrates that INIs will be susceptible to drug naïve HIV/AIDS patients in Korea.

A CMOS signal driver with with an order of magnitude smaller dI / dt noise than the conventional design without incurring the penalty of signal delay is described. A signal-reflection-suppressing ability, which comes from the configuration of driver circuit itself, is highlighted. The crosstalk noise of floating signal interconnection lines is analyzed and measured

In order to examine the use of a compliant cantilever structure as a contact scheme for a Multi-chip Interconnection System (MIS), multi-layer (metals and SiO2) cantilever beams were fabricated utilizing standard silicon processing and micromachining technologies. The mechanical behavior and electrical characteristics of the beams were investigated in order to establish their optimum dimensions for use in the MIS. During the course of this study, a new mechanical testing method for thin films has also been developed, which makes use of the same cantilever beam structure and a “Nanoindenter.” The Young's modulus and yield strength of thermally grown SiO2 and Au were measured using this technique.

The prediction and control of turbulent flow separation and reattachment continue to be important in many engineering applications. Although progress is being made in the understanding and prediction of these flows, the accurate and economical calculation of turbulent flows containing regions of recirculation still remains one of the major challenges in the field of computational fluid dynamics.

The results of a research program to develop and evaluate improved prediction methods for turbulent separating flows are summarized. The predictions of several turbulence models have been compared with experimental data for flows containing regions of recirculation using an inverse finite-difference method to solve the boundary layer equations. A new turbulence model which employs a one-dimensional transport equation for the outer-layer length scale was seen to provide the best agreement with the experimental data beyond separation. A viscous-inviscid interaction calculation procedure was developed to predict airfoil flows containing leading edge or midchord separation bubbles. The procedure utilized the inverse finite-difference method to predict the viscous flow and a small disturbance Cauchy integral formulation for the inviscid flow. Three models for laminar-turbulent transition were evaluated. Generally good agreement between predictions of the best model and measurements was observed in the several comparisons made. Some early results from a finite-difference scheme to solve the partially parabolized Navier-Stokes equations in primitive variables were also reported. The method was developed to predict viscous flows in which normal pressure gradients cannot be neglected.