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Department of PhysicsThe outstanding properties of graphene have enabled to reveal the exotic carrier transport behavior approaching to the relativistic quantum mechanics, act as the excellent diffusion barrier protecting the junction interface from the material intermixing by atomic diffusion, serve as the effective interlayer modulating the electronic states, and offer the promising solid-state platform allowing the quantum optics of the Dirac Fermion. In this dissertaion, the ballistic carrier transport through graphene in two different aspects will be covered. Understanding of vertical transport across graphene-combined hetero-junction and lateral transport in the graphene channel is the main agenda. The sensitive manipulation of electronic states at/across the interface and the controllable distribution of electric potential on the surface can lead to an extraordinary physical phenomenon and conductance switching. Based on that, it is eventually proposed that how the brand-new type graphene-based device can be evolved or what kind of method can be adapted to improve the actual performance of the graphene-based devices significantly regardless of property or quality of graphene.clos

Carpal Tunnel Syndrome Caused by Space Occupying Lesions

PURPOSE: To evaluate the diagnosis and treatment of the carpal tunnel syndrome (CTS) due to space occupying lesions (SOL). MATERIALS and METHODS: Eleven patients and 12 cases that underwent surgery for CTS due to SOL were studied retrospectively. We excluded SOL caused by bony lesions, such as malunion of distal radius fracture, volar lunate dislocation, etc. the average age was 51 years. There were 3 men and 8 women. Follow-up period was 12 to 40 months with an average of 18 months. the diagnosis of CTS was made clinically and electrophysiologically. in patients with swelling or tenderness on the area of wrist flexion creases, magnetic resonance imaging (MRI) and/or computed tomogram (CT) were additionally taken as well as the carpal tunnel view. We performed conventional open transverse carpal ligament release and removal of SOL. RESULTS: the types of lesion confirmed by pathologic examination were; tuberculosis tenosynovitis in 3 cases, nonspecific tenosynovitis in 2 cases, and gout in one case. Other SOLs were tumorous condition in five cases, and abnormal palmaris longus hypertrophy in 1 case. Tumorous conditions were due to calcifying mass in 4 cases and ganglion in 1 case. Following surgery, all cases showed alleviation of symptom without recurrence or complications. CONCLUSION: in cases with swelling or tenderness on the area of wrist flexion creases, it is important to obtain a carpal tunnel view, and MRI and/or CT should be supplemented in order to rule out SOLs around the carpal tunnel, if necessary.ope

Schottky Barrier Modulation of Metal/4H-SiC Junction with Thin Interface Spacer Driven by Surface Polarization Charge on 4H-SiC Substrate

The Au/Ni/Al2O3/4H-SiC junction with the Al2O3 film as a thin spacer layer was found to show the electrical characteristics of a typical rectifying Schottky contact, which is considered to be due to the leakiness of the spacer layer. The Schottky barrier of the junction was measured to be higher than an Au/Ni/4H-SiC junction with no spacer layer. It is believed that the negative surface bound charge originating from the spontaneous polarization of 4H-SiC causes the Schottky barrier increase. The use of a thin spacer layer can be an efficient experimental method to modulate Schottky barriers of metal/4H-SiC junctions.open

Sirolimus- Versus Paclitaxel-Eluting Stents for the Treatment of Coronary Bifurcations Results From the COBIS (Coronary Bifurcation Stenting) Registry

ObjectivesWe aimed to compare the long-term clinical outcomes of patients treated with sirolimus-eluting stents (SES) or paclitaxel-eluting stents (PES) for coronary bifurcation lesions.BackgroundThere are limited data regarding comparisons of SES and PES for the treatment of bifurcation lesions.MethodsPatients who received percutaneous coronary intervention for non-left main bifurcation lesions were enrolled from 16 centers in Korea between January 2004 and June 2006. We compared major adverse cardiac events (MACE [cardiac death, myocardial infarction, or target lesion revascularization]) between the SES and PES groups in patients overall and in 407 patient pairs generated by propensity-score matching.ResultsWe evaluated 1,033 patients with bifurcation lesions treated with SES and 562 patients treated with PES. The median follow-up duration was 22 months. Treatment with SES was associated with a lower incidence of MACE (hazard ratio [HR]: 0.53, 95% confidence interval [CI]: 0.32 to 0.89, p < 0.01) and target lesion revascularization (HR: 0.55, 95% CI: 0.31 to 0.97, p = 0.02), but not of cardiac death (HR: 2.77, 95% CI: 0.40 to 18.99, p = 0.62) and cardiac death or myocardial infarction (HR: 0.97, 95% CI: 0.38 to 2.49, p = 0.94). After propensity-score matching, patients with SES still had fewer MACE and target lesion revascularization incidences than did patients with PES (HR: 0.52, 95% CI: 0.30 to 0.91, p = 0.02, and HR: 0.48, 95% CI: 0.25 to 0.91, p = 0.02, respectively). There was no significant difference in the occurrences of stent thrombosis between the groups (0.7% vs. 0.7%, p = 0.94).ConclusionsIn patients with bifurcation lesions, the use of SES resulted in better long-term outcomes than did the use of PES, primarily by decreasing the rate of repeat revascularization. (Coronary Bifurcation Stenting Registry in South Korea [COBIS]; NCT00851526

A Case of Post-Streptococcal Glomerulonephritis with Diffuse Alveolar Hemorrhage

Acute post-streptococcal glomerulonephritis (PSGN) is characterized by an abrupt onset of edema, hypertension, and hematuria. Life-threatening diffuse alveolar hemorrhage (DAH) is rarely associated with acute PSGN. There have been only two reported cases worldwide, and no case has been reported previously in Korea. Here, we present a patient who clinically presented with pulmonary-renal syndrome; the renal histology revealed post-infectious glomerulonephritis of immune complex origin. A 59-yr-old woman was admitted with oliguria and hemoptysis two weeks after pharyngitis. Renal insufficiency rapidly progressed, and respiratory distress developed. Chest radiography showed acute progressive bilateral pulmonary infiltrates. The clinical presentation suggested DAH with PSGN. Three days after treatment with high-dose steroids, the respiratory distress and pulmonary infiltrates resolved. Electron microscopy of a renal biopsy specimen sample revealed diffuse proliferative glomerulonephritis with characteristic subendothelial deposits of immune complex ("hump"). The renal function of the patient was restored, and the serum creatinine level was normalized after treatment

Stroke awareness decreases prehospital delay after acute ischemic stroke in korea

BACKGROUND: Delayed arrival at hospital is one of the major obstacles in enhancing the rate of thrombolysis therapy in patients with acute ischemic stroke. Our study aimed to investigate factors associated with prehospital delay after acute ischemic stroke in Korea. METHODS: A prospective, multicenter study was conducted at 14 tertiary hospitals in Korea from March 2009 to July 2009. We interviewed 500 consecutive patients with acute ischemic stroke who arrived within 48 hours. Univariate and multivariate analyses were performed to evaluate factors influencing prehospital delay. RESULTS: Among the 500 patients (median 67 years, 62% men), the median time interval from symptom onset to arrival was 474 minutes (interquartile range, 170-1313). Early arrival within 3 hours of symptom onset was significantly associated with the following factors: high National Institutes of Health Stroke Scale (NIHSS) score, previous stroke, atrial fibrillation, use of ambulance, knowledge about thrombolysis and awareness of the patient/bystander that the initial symptom was a stroke. Multivariable logistic regression analysis indicated that awareness of the patient/bystander that the initial symptom was a stroke (OR 4.438, 95% CI 2.669-7.381), knowledge about thrombolysis (OR 2.002, 95% CI 1.104-3.633) and use of ambulance (OR 1.961, 95% CI 1.176-3.270) were significantly associated with early arrival. CONCLUSIONS: In Korea, stroke awareness not only on the part of patients, but also of bystanders, had a great impact on early arrival at hospital. To increase the rate of thrombolysis therapy and the incidence of favorable outcomes, extensive general public education including how to recognize stroke symptoms would be important.ope

The Prevalence of Human Papillomavirus Infection in Korean Non-Small Cell Lung Cancer Patients

Human papillomavirus (HPV) infection is a co-carcinogen of lung cancer and contributes to its pathogenesis. To evaluate the prevalence of HPV infection, polymerase chain reaction (PCR) was employed to detect HPV 16, 18, and 33 DNA in tumor tissues of 112 patients with non-small cell lung cancer (NSCLC) who underwent curative surgery from Jan. 1995 to Dec. 1998 at Severance Hospital, Seoul, Korea. The patients consisted of 90 men and 22 women. Nineteen patients were under 50 years old (17%), and 92 patients (82%) were smokers. Fifty-three patients had adenocarcinomas, while 59 patients had non-adenocarcinomas. Early stage (I and II) cancer was found in 64 patients (57.1%) and advanced stage (III and IV) found in 48 (42.9%). The prevalence of HPV 16, 18, and 33 were 12 (10.7%), 11 (9.8%), and 37 (33.0%), respectively. Smoking status, sex, and histologic type were not statistically different in the presence of HPV DNA. The presence of HPV 16 was more common in younger patients and HPV 18 was more common in advanced stage patients. This study showed that the prevalence rate of HPV 16 and 18 infections in NSCLC tissue was low, suggesting HPV 16 and 18 infections played a limited role in lung carcinogenesis of Koreans. However, the higher prevalence of HPV 33 infections in Korean lung cancer patients compared to other Asian and Western countries may be important and warrants further investigation

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference