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We developed highly efficient quantum dot light-emitting devices (QD-LEDs) by improving the charge balance with triple hole injection and transport layers consisted of MoO3/poly[N,N′-bis(4-butylphe...

Microreactors are emerging as an efficient, sustainable synthetic tool compared to conventional batch reactors. Here, we present a new numbering-up metal microreactor by integrating a flow distributor and a copper catalytic module for high productivity of a commercial synthetic drug. A flow distributor and an embedded baffle disc were manufactured by CNC machining and 3D printing of stainless steel (S/S), respectively, whereas a catalytic reaction module was composed of 25 copper coiled capillaries configured in parallel. Eventually, the numbering-up microreactor system assembled with functional modules showed uniform flow distribution and high mixing efficiency regardless of clogging, and achieved high-throughput synthesis of the drug "rufinamide", an anticonvulsant medicine, via a Cu(i)-catalyzed azide-alkyne cycloaddition reaction under optimized conditions.

We report an influence of abnormal mixing effect of host systems having undesirable energy level and transport level in the emission layer (EML). Rather, we focused on their device performance and stability (e.g. driving lifetime) when it was prepared by solution-process. The resultant green phosphorescent organic light emitting diodes (s-OLEDs) showed reasonable device performance and interesting photo-physical properties, which revealed that we can achieve good performance if an appropriate compromise between the factors which govern a charge transport and an energy transfer processes can be realized albeit the EML has undesirable host systems with both bad energy level matching (e.g., HOMO, LUMO levels) and charge transport properties. In this study, a high performance of the s-OLEDs by controlling photo-physical pathways such as exciton quenching process (e.g. triplet-triplet annihilation). Besides, such kind of change in photo-physical pathway may be optimized by controlling the charge balance (i.e. carrier transport behaviour) where we intentionally selected N- and P-type host materials (denote NH and PH, respectively) with abnormal HOMO and LUMO energy levels.

Background : This study evaluated functional outcomes using newly established clinical pathways after hip fracture surgery in older adults and analyzed the major determinants of successful functional outcomes in rehabilitation programs using standardized clinical pathways. Methods : This was a retrospective cohort study performed in a tertiary rehabilitation facility. A total of 220 patients who had received unilateral hip fracture surgery were followed up from immediately after surgery to 6 months postoperatively. Clinical pathways for rehabilitation included early, individualized rehabilitation, education for activities of daily living, review of general medical conditions, and arrangement of discharge settings. One rehabilitation specialist consecutively checked ambulatory function using 3-level grading, and patients were classified into good recovery and poor recovery groups based on ambulatory function at 6 months postoperatively. Logistic regression analysis was performed using 7 representative variables (age, sex, bone mineral density, Mini-Mental Status Examination [MMSE], Berg Balance Scale [BBS], premorbid ambulatory function, and length of hospital stay). Results : A total of 86.8% of patients could walk with or without assistance at 6 months after surgery and 75.5% of patients involved in the rehabilitation program were classified into the good recovery group in this study. The good recovery group showed higher MMSE and BBS scores compared with the poor recovery group. The factors in the model most strongly correlated with recovery were MMSE and BBS. Conclusion : This study showed that a well-designed rehabilitation program could improve ambulatory function in older patients after hip fracture surgery and that cognitive impairment and poor balance control may inhibit the recovery of ambulatory function.

A novel cross-linkable hole transport material (HTM) was used to form a robust layer structure upon continuous wet processes such as spin coating or ink-jet printing. The significantly reduced hole mobility of the cross-linked HTM (x-HTM) was dramatically improved by a semi-interpenetrating polymer network (semi-IPN) approach for ideal charge balance. In other words, we obtained a synergistic effect from the blending of a linear hole transport polymer [TFB, poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine)] with a new x-HTM that realizes pretty low solubility in common organic solvents as well as significantly enhanced hole transport characteristics. As a result, it gave highly efficient solution-processed green phosphorescent organic light-emitting diodes (PHOLEDs) showing a pretty high current efficiency and external quantum efficiency of approximately 51.6 cd A−1 and 14.6% at the blending ratio of 20% (TFB). Particularly, the device lifetime was remarkably improved by a factor of 6.5 compared to the reference device which used an intrinsic x-HTM. To understand the reason for such outstanding improvement, we performed impedance spectroscopy (IS).

Eu3+-activated WO3-Eu2(WO4)3 luminescent composite thin films are grown on low-cost slide glass substrates by radio frequency sputtering and then annealing in an air atmosphere furnace. The films obtained by sputtering 12 at.% of Eu-added WO3 target afforded a two-phase composite structure comprising Eu-doped WO3 and Eu2(WO4)3 after annealing. The composite thin films annealed at 600 °C exhibited strong red emission after growing at room temperature compared to those annealed at 500 °C under the excitation of 254, 394, and 465 nm corresponding to ultraviolet, near-ultraviolet, and blue light, respectively. The thin films grown at low temperatures without annealing did not emit under ultraviolet light. The crystalline structure, surface morphology, and optical properties, such as transmittance and photoluminescence, of the films grown at 500 °C were almost similar to those of the thin films grown at room temperature when they were annealed at the same temperature. Pure WO3 thin films without Eu doping showed similar crystallization behavior under the same annealing conditions as Eu-added composite films; however, they did not exhibit photoluminescence properties. Our report on the integration of thin-film red phosphors on glass substrates is promising for the development of low-cost and large-area optical devices activated at various excitation wavelengths.

This study aims at analyzing the convergence of Internet-of-Things and wearables technologies using cooperative patent classification(CPC). CPC, introduced to an increasing number of technological fields of Korean patents, is expected to be widely used in Patent Informatics because the classification codes in CPC are more specific than those of IPC, which reflect the characteristics of technologies in detail with accuracy. CPC has seldom been used up to date and most of the previous researches on technological convergence used IPC. As a pre-analysis step for analyzing the trend of technological convergence of IoT and wearables, CPC and IPC codes assigned to each patent were compared. By applying association rule mining to the analysis of CPC codes, we identified the technological fields where convergence frequently takes place and examined the trend of technological convergence over time.

The minimum-weight design of compressively loaded composite plates and composite stiffened panels under constrained postbuckling strength is addressed herein. A nonlinear finite element code, COSAP (COmposite Structural Analysis Program) was applied to analyze the buckling and postbuckling behavior. As an optimization technique, a modified Genetic Algorithm was used to find the optimum points. The parallel computing scheme was implemented with MPI (Message Passing Interface) library and realized in a parallel-computing supercomputer and a pc cluster. The optimal design was performed with two chosen examples: a composite plate and a composite stiffened panel. The design variables were the number of plies and the ply angle in each ply. In case of the stiffened panels, the size and the location of the stiffeners were also considered as the design variables. The objective function was defined as the product of the nondimensional weight and the strength. The optimization results showed better performances than conventional designs.

This research aims to establish an optimal design method of filament wound structures under internal pressure. So far, most design and manufacturing of filament wound structures have been based on manufacturing experiences, and there is no established design rule. In this research, the semi-geodesic path algorithm was used to calculate possible winding patterns taking into account the windability and slippage between the fiber and the mandrel surface. In addition, finite element analyses using commercial code, ABAQUS, were performed to predict the behavior of filament wound structures. On the basis of the semi-geodesic path algorithm and the finite element analysis method, a filament wound structure was designed using the genetic algorithm.

Graphite blocks are important core components of the high temperature gas-cooled reactor. As these blocks are simply stacked in array, collisions among neighboring components may occur during earthquakes or accidents. Thus, it is important to develop a reliable seismic model of the stacked graphite blocks and have them designed to maintain their structural integrity during the anticipated occurrences. Various aspects involved in modeling and calculating impact-contact dynamics can affect the resulting behavior of the graphite block. These include mesh size, time step, contact behavior, mechanical constraint formulation of impact-contact analysis, etc. This work is dedicated to perform comparative studies and the effects of these parameters will be identified. The insights obtained through these studies will help build a realistic impact-contact model of the graphite block from which a lumped or reduced dynamics model will be developed for the seismic analysis of the reactor including these graphite components.

The objective of this research was to develop a practical integrated approach using extracted features from electrical resistance measurements and coupled electromechanical models of damage, for in situ damage detection and sensing in carbon fiber reinforced plastic (CFRP) composite structures. To achieve this objective, we introduced specific known damage (in terms of type, size, and location) into CFRP laminates and established quantitative relationships with the electrical resistance measurements. For processing of numerous measurement data, an autonomous data acquisition system was devised. We also established a specimen preparation procedure and a method for electrode setup. Coupon and panel CFRP laminate specimens with several known damage were tested and post-processed with the measurement data. Coupon specimens with various sizes of artificial delaminations obtained by inserting Teflon film were manufactured and the resistance was measured. The measurement results showed that increase of delamination size led to increase of resistance implying that it is possible to sense the existence and size of delamination. Encouraged by the results of coupon specimens, we implemented the measurement system on panel specimens. Three different quasi-isotropic panels were designed and manufactured: a panel with artificial delamination by inserting Teflon film at the midplane, a panel with artificial delamination by inserting Teflon film between the second and third plies from the surface, and an undamaged panel. The first two panels were designed to determine the feasibility of detecting delamination using the developed measurement system. The third panel had no damage at first, and then three different sizes of holes were drilled at a chosen location. Panels were prepared using the established procedures with six electrode connections on each side making a total of twenty-four electrode connections for a panel. All possible pairs of electrodes were scanned and the resistance was measured for each pair. The measurement results showed the possibility of the established measurement system for an in-situ damage detection method for CFRP composite structures.

Few studies have investigated the association between age at smoking initiation and Fagerström test for nicotine dependence (FTND) in adulthood. The goal of this study was to develop the Korean version of FTND (FTND-K) and to examine the relationship between age at smoking initiation and nicotine dependence.This investigation used data from 268 current smokers who visited the Center for Cancer Prevention and Early Detection in the National Cancer Center, Korea. The internal consistency of the FTND-K was assessed by Cronbach's coefficient alpha. Pearson's correlation coefficients were used to assess the relationships between the FTND-K sum scores and urinary cotinine levels. One-way analysis of variance (ANOVA) and t-tests were used to assess differences in the FTND-K sum score between groups. Factor associated with nicotine dependence were identified through stepwise multiple logistic regression analysis.The standardized Cronbach's alpha of FTND-K was 0.72. A significant positive correlation was seen between the FTND-K sum score and urinary cotinine level (correlation coefficient = 0.49, P0.05). Age at smoking initiation had a significant association with the FTND-K sum score in univariate analysis. In multivariate analysis, nicotine dependence was higher in smokers that started smoking cigarettes at 19 years or earlier than in those that started at 25 years or later (OR = 11.25, 95% CIs, 1.46-97.10).The FTND-K is a valid assessment tool of nicotine dependence with acceptable levels of internal consistency and close correlation to urinary cotinine level. The finding that those who initiate smoking at an early age tend to be more nicotine dependent underscores and reinforces the public health significance of delaying smoking onset.

Background : The objective of this study was to understand sleep-related problems, and to determine whether the sleep questionnaires is a clinically useful method in patients who need polysomnography. Methods : Subjects were patients who performed polysomnography and who asked to answer a sleep questionnaires at the Sleep Disorders Clinic of St. Paul's Hospital, Catholic University of Korea. Baseline characteristics, past medical illness, behaviors during sleep-wake cycle, snoring, sleep-disordered breathing and symptoms of daytime sleepiness were analyzed to compare with data of polysomnography. Results : The study population included 1081 patients(849 men, 232 female), and their mean age was . Among these patients, 38.9% had an apnea-hypopnea index(AHI), 13.2% had , and 20.0% had . The main problems for visiting our clinic were snoring(91.7%), sleep apnea(74.5%), excessive daytime sleepiness(8.0%), insomnia(4.3%), bruxism(1.1%) and attention deficit(0.5%). The mean value of frequency of interruptions of sleep was 1.6 and the most common reason was urination(46.3%). Epworth Sleepiness Scale(ESS) had a weak correlation with AHI(r=0.209, p

An 81-year-old man underwent bronchoscopy to investigate the cause of his dyspnea symptoms. A benign natured mass was observed in the bronchus and was excised. The pathology examination revealed a fibroepithelial polyp. He has been asymptomatic since the simple bronchoscopic excision. A fibroepithelial polyp is a benign tumor with a mesodermal origin. It is commonly found in the skin, urogenital area and chest, but is extremely rare in the respiratory system. We report a case of a fibroepithelial polyp in the bronchus, which was treated with a bronchoscopic excision, with a brief review of the relevant literature.

We report a case of a 48-year-old man with a paradoxic upper airway obstruction and central sleep apnea that developed after an anterior cervical spinal fusion. Nine months before being admitted to this hospital, he was diagnosed with a herniated intervertebral disc between the 5th and 6th cervical spine, and the first operation was carried out. Two months later, a pseudoarthrosis has developed and a second operation, an anterior interbody fusion of the C5 and C6 using autogenous strut bone graft, was performed. After the second operation, he began to complain of snoring, excessive daytime sleepiness, insomnia, and a bizarre sound heard near the upper airway during breathing. Nasopharyngoscope and magnetic resonance imaging disclosed a paradoxical narrowing of the nasopharynx during expiration. On the overnight polysomnography, the apnea index was 8.7/h (central apnea, 7.0/h; obstructive apnea, 1.7/h). Nasal continuous positive airway pressure was applied, but he complained of pressure-intolerance, and laser-assisted uvulopalatoplasty was then performed. Two months after surgery, clinical symptoms as well as the apneas had improved markedly. We suggest that this paradoxic upper airway obstruction might be associated with the anterior cervical spinal surgery even though the mechanism is unclear. This case also emphasizes that an upper airway obstruction can contribute to the development of central sleep apnea. (Tuberc Respir Dis 2005; 58:294-298)

Background : Obstructive sleep apnea syndrome (OSAS) is believed to have multifactorial causes. The major risk factors for OSAS are obesity, narrowed upper airways, and abnormal cranial-facial structures. A genetic basis for OSAS has been also suggested by reports of families with many members affected. This study analyzed the HLA typing in patients with OSAS to determine the possible role of genetics in OSAS. Methods : Twenty-five Korean patients with OSAS (1 woman and 24 men; age range 30-66 years) were enrolled in this study. A diagnosis of OSAS was made using full-night polysomnography. The control group consisted of 200 healthy Korean people. Serologic typing of the HLA-A and B alleles was performed in all patients using a standard lymphocyte microcytotoxicity test. Analysis of the polymorphic second exons of the HLA-DRB1 gene was performed using a polymerase chain reaction-sequence specific oligonucleotide probe. Results : The allele frequency of HLA-A11 was significantly lower in patients with OSAS compared with the controls (p45) than in the controls (p

A 47-year-old female was admitted for an evaluation of a left mediastinal mass. The chest X-ray performed 16 months ago was normal, but the chest X-ray upon admission showed a large mass adjacent to the anterior aspect of the left hemidiaphragm. The CT scan demonstrated a large mass with a fat density in the left lower hemithorax. A focal diaphragmatic defect behind the xiphoid process was suspected. A thoracoscopic examination revealed omental herniation through the diaphragmatic defect. Therefore, a left thoracotomy was performed and the defect was repaired. We believe that a differential diagnosis should be needed to include a diaphragmatic omental hernia when a fat density mass is observed in the mediastinum.

Background : Patients with obstructive sleep apnea syndrome are known to have high long-term mortality compared to healthy subjects because of their cardiovascular dysfunction. The observation of hemodynamic changes by obstructive apneas is helpful when attempting to understand the pathophysiological mechanism of the development of cardiovascular dysfunction in those patients. Therefore, we studied the changes in cardiovascular function with an animal model and tried to obtain the basic data for an ideal experimental model (this phrase is unclear), a requirement for a more advanced study. Methods : Sixteen anesthetized dogs with -chloralose delete were divided into two groups : 8 dogs of room air breathing group and 8 dogs of oxygen breathing group. We measured , , heart rate, cardiac output, mean femoral artery pressure, and mean pulmonary artery pressure at specified times during the apnea-breathing cycle before endotracheal tube occlusion (baseline), 25 seconds after endotracheal tube occlusion (apneic period), 10 seconds (early phase of postapneic period, EPA) and 25 seconds (late phase of postapneic period, LPA) after spontaneous breathing. Results : In room air breathing group, the heart rate significantly decreased during the apneic period compared to that at baseline (P

연구배경 : 폐쇄성 수면 무호흡 증후군 환자는 수면중에 전신성 혈압의 상승과 심박동수의 현저한 변화를 보이며, 이러한 심혈관계 기능변화는 수면중 반복되는 무호흡에 의한 저산소증과 각성반응으로 인한 교감신경계 활성도 변화와 관련이 있을 것으로 생각되고 있다. 지속적 기도 양압 공급(CPAP) 치료는 폐쇄성 수면 무호흡을 가장 확실하게 치료할 수 있는 방법으로 알려져 있으나 이러한 치료법이 환자들의 심혈관계 교감신경계 활성도에 어떠한 영향을 미치는 지에 대해서는 명확히 알려져 있지 않다. 이에 저자들은 폐쇄성수면 무호흡 증후군 환지에서 CPAP 치료 적용시 나타나는 심혈관계 및 교감신경계 활성도 변화를 관찰하고자하였다. 방법 : 수면다원검사에서 폐쇄성 수면 무호흡 증후군으로 진단되어 CPAP 치료를 시행한 13명을 대상으로 치료 전과 후의 수면다원검사의 각 지표, 수면중 전신성 혈압, 수면중 심박동수와 부정맥, 그리고 혈장 catecholamines 농도 변화를 비교 분석하였다. 결과 : 수면다원검사의 각 지표중 CPAP 치료 후 무호흡-저호흡지수는 유의하게 감소하였고(p 【Background : Obstructive sleep apnea syndrome (OSAS) affects systemic blood pressure and cardiac function. The development of cardiovascular dysfunction including the changes of systemic blood pressure and cardiac rhythm, suggests that recurrent hypoxia and arousals from sleep may increase a sympathetic nervous system activity. Continuous positive airway pressure (CPAP) therapy has been found to be an effective treatment of OSAS. However, only a few studies have investigated the cardiovascular and sympathetic effects of CPAP therapy. We evaluated influences of nasal CPAP therapy on the cardiovascular system and the sympathetic activity in patients with OSAS. Methods : Thirteen patients with OSAS underwent CPAP therapy and were monitored using polysomnography, blood pressure, heart rate, presence of arrhythmia and the concentration of plasma catecholamines, before and with CPAP therapy. Results: The apnea-hypopnea index (AHI) was significant1y decreased (p】

Pneumonia caused by Mycoplasma pneumoniae is usually a mild and self-limited infection. Chest films usually show patch consolidation or interstitial infiltration in the lung. We recently encountered a case of fulminant Mycoplasma pneumonia which showed rapidly progressing extensive bilateral airspace consolidation with pleural effusion. A previously healthy 19-year-old female college student was admitted to the hospital because of fever and dry cough. Chest X-ray showed large areas of airspace consolidation in both lung with pleural effusion and rapid progression of the lung lesion. The diagnosis of Mycoplasma pneumonia was made from the serologic test Here we report a case of Mycoplasma pneumonia showing unusual manifestation.