A spacer grid assembly, which is an interconnected array of slotted grid straps welded at the intersections to form an egg crate structure, is one of the core structural components of the nuclear fuel assemblies of a Pressurized light Water Reactor (PWR). The spacer grid assembly is structurally required to have enough buckling strength under lateral loads so that the nuclear fuel rods are maintained in a coolable geometry, and that control rods are able to be inserted. The ability of a spacer grid assembly to resist lateral loads is usually characterized in terms of its dynamic and static crush strengths. Since the crush strengths of a spacer grid assembly are known to depend on the weld qualities at the intersections of the slotted grid straps, high-tech welding methods, such as a TIG welding, LASER beam welding or Electron beam welding method, have been used recently in the nuclear fuel manufacturing fields. In this study, to meet the above requirements, two kinds of researches were carried out. First, by adjusting the LASER beam welding parameters, an optimum welding combination of the LASER beam welding parameters was obtained for welding a spacer grid assembly. Second, a new LASER beam welding technique was proposed to obtain a longer weld line and a smaller weld bead size by tilting the LASER beam. The buckling strength of the spacer grid welded by the new LASER beam welding technique was enhanced by up to 30 % when compared to that by the conventional LASER beam welding method.

Background: The effect of pravastatin on insulin resistance (IR) is controversial and poorly studied in prediabetes. Methods: This study was performed in hyperglycemic patients at Saint Carollo Hospital from January 1, 2013 to December 31, 2015. Among them, we selected 40 patients (24 prediabetes and 16 new onset diabetes [NOD]) who had been treated with pravastatin 20 mg daily for 2 or 4 months and in whom fasting insulin and fasting glucose had been measured before and after administration of pravastatin. IR was defined as a fasting insulin level ≥ 12.94 μU/mL, homeostasis model for IR (HOMA-IR) ≥ 3.04 or quantitative insulin sensitivity check index (QUICKI) ≤ 0.32. Results: Pravastatin treatment decreased total cholesterol and low-density lipoprotein cholesterol levels by 25.2% and 32.3% respectively (P = 0.000 for all), but did not affect fasting insulin level, HOMA-IR, or QUICKI in total, prediabetes, and NOD groups. Prevalence of IR was significantly different between prediabetes and NOD groups both before and after pravastatin treatment (0% versus 37.5%, P = 0.001), but pravastatin treatment did not affect the prevalence of IR in the prediabetes or NOD group. Fasting glucose level was not significantly different before and after pravastatin treatment in prediabetes (106.8 ± 6.4 mg/dL versus 103.8 ± 8.4 mg/dL, P = 0.223) but was significantly different in the NOD group (171.5 ± 혈당이 높은 환자에서 Pravastatin이 인슐린 저항성에 미치는 영향 정용진, 김정민, 장승재, 방준희, 정영곤, 김성택, 강순형, 최종인, 김수성, 강미연

Spontaneous pneumothorax occurs in a variety of lung diseases. Primary or metastatic lung cancers are rare, but important causes of pneumothorax. We report here on a case of pulmonary metastasis of thyroid papillary carcinoma that initially presented as spontaneous pneumothorax. A 32-year-old male with no history of thyroid disease underwent wedge resection of the lung due to recurrent pneumothorax. Histologically, the pleura and subpleural lung parenchyma revealed several micronodular lesions and randomly scattered glandular structures with mild cytological atypia. The cells were characterized by their overlapped hypochromatic nuclei with longitudinal grooves and inconspicuous nucleoli. On the additional sections, we found a few intranuclear inclusions and colloid-like material in the follicular structures. The glandular cells were immunoreactive for thyroglobulin, TTF-1, CK 7 and HMW-CK and they were focally immunoreactive for EMA, but they were negative for S100, chromogranin and CEA. The Ki-67 labelling index was 4%. Neck ultrasonography revealed an ill-defined hypoechoic nodule in the left lobe of the thyroid. The diagnosis of conventional, classical papillary carcinoma was made by both the cytology and the total thyroidectomy specimen. Pathologists should conduct a through histologic examination for the patients with recurrent spontaneous pneumothorax to search for the underlying causes.

The remote resistance welding technology in the hot cell environment for DUPIC (Direct Use of spent PWR fuel In CANDU reactors) fuel fabrication was established. To do this, a preliminary investigation for hands-on fuel fabrication outside the hot cell was conducted in the consideration of constraints caused by welding in the hot cell. Further welding experiments were carried out to improve the RW process. A remote resistance welding apparatus was developed. The characteristics of welds made by RW and LBW were compared in terms of the weld nugget penetrations and torque strength. It was found that resistance welding was a more suitable welding process for joining the endplate to the end caps in the hot cell. The optimum conditions for RW in the hot cell operation in a remote manner were also obtained.

Kimura's disease is a chronic infl ammatory disease producing subcutaneous tumor-like nodules chiefl y in the head and neck region. It is characterized histologically by lymphoid follicles, intense aggregations of eosinophils, vascular proliferation and fibrosis combined with peripheral blood eosinophilia. We report a 56-year-old man who presented with dysarthria and right hemiparesis. On physical examination, a non-ender mass 5 × 6 cm was identifi ed in the right submandibular area. He was diagnosed with Kimura's disease by biopsy. One month after admission, he complained of paresthesia in the left lower extremity. CT angiography revealed thromobosis in the left femoral vein and bilateral pulmonary embolism. To our knowledge, the concomitant occurrence of acute cerebral infarction, deep vein thrombosis and pulmonary embolism in patients with Kimura's disease has never been reported. Eosinophil-derived cytotoxic proteins are presumed to be fundamental to the pathogenesis of these disorders in Kimura's disease.