522 research outputs found

    Growth of transparent conductive Al-doped ZnO thin films and device applications

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    High-purity transparent conductive Al-doped ZnO (AZO) films were grown by KrF excimer pulsed laser deposition. We used ultraviolet and X-ray photoelectron spectroscopes to directly measure the absolute values of the vacuum work function of AZO films. The structure and electrical and optical properties of the as-grown AZO films were studied using X-ray diffraction, room temperature Hall effect measurement and spectro photometer, respectively. Finally, organic light emitting diodes (OLED) were fabricated on these AZO films. OLED device measurement showed that the current of the OLED with AZO was clearly increased. Our AZO thin films showed a higher conductivity (& ¼ 1:33 Â 10 À4 cm, R s ¼ 10:1 /sq) than conventional indium tin oxide films

    Acute kidney injury in patients with acute-on-chronic liver failure: clinical significance and management

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    Acute-on-chronic-liver failure (ACLF) refers to a phenomenon in which patients with chronic liver disease develop multiple organ failure due to acute exacerbation of underlying liver disease. More than 10 definitions of ACLF are extant around the world, and there is lack of consensus on whether extrahepatic organ failure is a main component or a consequence of ACLF. Asian and European consortiums have their own definitions of ACLF. The Asian Pacific Association for the Study of the Liver ACLF Research Consortium does not consider kidney failure as a diagnostic criterion for ACLF. Meanwhile, the European Association for the Study of the Liver Chronic Liver Failure and the North American Consortium for the Study of End-stage Liver Disease do consider kidney failure as an important factor in diagnosing and assessing the severity of ACLF. When kidney failure occurs in ACLF patients, treatment varies depending on the presence and stage of acute kidney injury (AKI). In general, the diagnosis of AKI in cirrhotic patients is based on the International Club of Ascites criteria: an increase of 0.3 mg/dL or more within 48 hours or a serum creatinine increase of 50% or more within one week. This study underscores the importance of kidney failure or AKI in patients with ACLF by reviewing its pathophysiology, prevention methods, and treatment approaches

    Separated pulsed laser deposition for nanostructured thin films

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    Abstract We have developed an alternative laser deposition technique for preparation of droplet-free thin films and fine particles. This separated pulsed laser deposition (SPLD) consists of an ablation chamber and a deposition chamber which are independently evacuated under different ambient gases. High quality ZnO films exhibiting both particle-free and uniform deposition were obtained such as at an ablation pressure of 5 mTorr (Ar) and a deposition pressure of 10 mTorr (O 2 ). It is shown that, when the bias voltage and magnetic field are simultaneously applied in the deposition chamber, the E × B drift motion of about 70 km/s over the substrates contributes to deposit the smooth and high quality films. XRD and optical transmittance for the deposited films were investigated to clarify the operating properties of the SPLD assisted by the electric field and magnetic field. This SPLD is a promising technique for preparation of films and nanostructured particles

    BOAO Photometric Survey of Galactic Open Clusters. III. Czernik 24 and Czernik 27

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    We present BV CCD photometry for the open clusters Czernik 24 and Czernik 27. These clusters have never been studied before, and we provide, for the first time, the cluster parameters; reddening, distance, metallicity and age. Czernik 24 is an old open cluster with age 1.8 +/- 0.2 Gyr, metallicity [Fe/H]=-0.41 +/- 0.15 dex, distance modulus (m-M)_0 = 13.1 +/- 0.3 mag (d=4.1 +/- 0.5 kpc), and reddening E(B-V) = 0.54 +/- 0.12 mag. The parameters for Czernik 27 are estimated to be age = 0.63 +/- 0.07 Gyr, [Fe/H]= -0.02 +/- 0.10 dex, (m-M)_0 = 13.8 +/- 0.2 mag (d=5.8 +/- 0.5 kpc), and E(B-V) = 0.15 +/- 0.05 mag. The metallicity and distance values for Czernik 24 are consistent with the relation between the metallicity and the Galactocentric distance of other old open clusters. We find the metallicity gradient of 51 old open clusters including Czernik 24 to be Delta [Fe/H]/Delta R_gc= -0.064 +/- 0.009 dex/kpc.Comment: Accepted by the Journal of the Korean Astronomical Society, 2005 December issu

    A Comparative Study on the Efficacy of Covered Metal Stent and Plastic Stent in Unresectable Malignant Biliary Obstruction

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    Background/AimsThe placement of self expandable metal stent (SEMS) is one of the palliative therapeutic options for patients with unresectable malignant biliary obstruction. The aim of this study was to compare the effectiveness of a covered SEMS versus the conventional plastic stent.MethodsWe retrospectively evaluated 44 patients with unresectable malignant biliary obstruction who were treated with a covered SEMS (21 patients) or a plastic stent (10 Fr, 23 patients). We analyzed the technical success rate, functional success rate, early complications, late complications, stent patency and survival rate.ResultsThere was one case in the covered SEMS group that had failed technically, but was corrected successfully using lasso. Functional success rates were 90.5% in the covered SEMS group and 91.3% in the plastic stent group. There was no difference in early complications between the two groups. Median patency of the stent was significantly prolonged in patients who had a covered SEMS (233.6 days) compared with those who had a plastic stent (94.6 days) (p=0.006). During the follow-up period, stent occlusion occurred in 11 patients of the covered SEMS group. Mean survival showed no significant difference between the two groups (covered SEMS group, 236.9 days; plastic stent group, 222.3 days; p=0.182).ConclusionsThe patency of the covered SEMS was longer than that of the plastic stent and the lasso of the covered SEMS was available for repositioning of the stent

    Robotic pylorus preserving pancreaticoduodenectomy with mini-laparotomy reconstruction in patient with ampullary adenoma

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    Robotic surgical system provides many unique advantages which might compensate the limitations of usual laparoscopic surgery. By using robotic surgical system, we performed robot-assisted laparoscopic pancreaticoduodenectomy (PD). A Sixty-two year old female patient with an ampullary mass underwent robot assisted PD due to imcomplete treatment of endoscopic ampullectomy. The removal of specimen and reconstruction were performed through small upper midline skin incision. Robot working time was about 8 hours, and blood loss was about 800 ml without blood transfusion. She returned to an oral diet on postoperative day 3. Grade B pancreatic leak was noted during the postoperative period, but was successfully managed by conservative management alone. We successfully performed da Vinci-assisted laparoscopic PD, and robot surgical system provided three-dimensional stable visualization and wrist-like motion of instrument facilitated complex operative procedures. More experiences are necessary to address real role of robot in far advanced laparoscopic pancreatic surgery

    Nonspecific Interstitial Pneumonitis after Bortezomib and Thalidomide Treatment in a Multiple Myeloma Patient

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    Bortezomib, an inhibitor of 26S proteosome, is recently approved treatment option for multiple myeloma. Thalidomide, a drug with immunomodulating and antiangiogenic effects, has also shown promise as an effective treatment in multiple myeloma. Pulmonary complications are believed to be rare, especially interstitial lung disease. Here, we describe a patient with dyspnea and diffuse pulmonary infiltrates while receiving bortezomib and thalidomide in combination with dexamethasone for treatment-naïve multiple myeloma. Bronchoalveolar lavage demonstrated a significant decrease in the ratio of CD4 : CD8 T lymphocytes (CD4/8 ratio, 0.54). Extensive workup for other causes, including infections, was negative. A lung biopsy under video-assisted thorascopic surgery revealed a diagnosis of nonspecific interstitial pneumonitis. The symptoms and imaging study findings improved after initiating steroid treatment. Physicians should be aware of this potential complication in patients receiving the novel molecular-targeted antineoplastic agents, bortezomib and thalidomide, who present with dyspnea and new pulmonary infiltrates and fail to improve despite treatment with broad-spectrum antibiotics
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