In recent years, there has been a need for cooling technology that can deal with the increase of heat generation by the miniaturization and high output of electronic devices. Fin-type heat sink with ...boiling cooling can be a new method that can cool the electronic devices efficiently. But, at the same time, its pressure drop will also increase. The increasing pressure drop may result in the deterioration of the heat transfer efficiency. So, it' s important to estimate the pressure drop through the heat sink. In previous studies, although most researchers have already studied the pressure drop of the fin-type heat sink, there are only a few studies treating the pin-fin as packed material in a packed bed system, which might have a possibility for general expression of pressure drop. Therefore, in this study, the pressure drop through the fin-type heat sink with the single-/two-phase flow is measured, and Ergun/Lipinski model is employed to evaluate the experimental results.
We report the rare case of a 69-year-old man who underwent resection of a mixed adenoneuroendocrine carcinoma (MANEC) of the distal bile duct and a carcinoma in situ in the perihilar bile duct. The ...patient was admitted to our hospital for obstructive jaundice. Imaging studies revealed a mass in the distal bile duct, and an abnormal epithelium was detected in the perihilar bile duct using peroral cholangioscopy. Bile cytology and transpapillary biopsy of the tumor revealed adenocarcinoma. We diagnosed this patient with distal cholangiocarcinoma with extensive intraepithelial progression toward the perihilar bile duct and performed a subtotal stomach-preserving pancreaticoduodenectomy and left hepatectomy. According to the histological examination of the resected specimens, we found a MANEC in the distal bile duct and a carcinoma in situ in the perihilar bile duct. Together, they were diagnosed as synchronous double primary cancers due to the lack of pathological transition between them.
A metal stent has a longer stent patency than a plastic stent in patients with unresectable malignant distal biliary stricture. However, treatment for stent dysfunction of a metal stent remains ...unresolved. A review of reported articles regarding reintervention for metal stent dysfunction showed that causes of stent dysfunction included tumor ingrowth/overgrowth, stone/sludge/food impaction, and stent migration. Cleaning of the stent is associated with an early relapse of stent dysfunction. Additional placement of a covered metal stent is expected to have a longer stent patency than that of other stents such as uncovered metal stents or plastic stents. It is recommended that occludedcovered metal stents be removed if possible. Stent trimming with argon plasma coagulation is sometimes useful for the treatment of stent displacement. No strategy for occluded metal stents has been established yet. Further clinical trials regarding proper treatments are necessary.
In the safety study on a sodium-cooled fast reactor, it is assumed that the high-temperature fuel debris are formed because of a core disruptive accident. During the cooling of the fuel debris, ...gas-liquid two-phase flow can be generated in the debris due to the coolant boiling. To improve the prediction accuracy of the flow characteristics, detailed measurement of the gas-liquid two-phase flow in the debris bed is required. In this study, gas-liquid two-phase flow in a quasi-two-dimensional sphere-packed bed, which simulates the debris bed, is visualized by using X-ray imaging. The experimental results show that the local void fraction increases near the splitting section in the packed bed and decreases near the coalescence section.
Objective : To examine the effectiveness of a newly developed emergency room (ER) protocol to treat patients with stroke and control the spread of SARS-CoV-2 by evaluating the door-to-picture time. ...Methods : We retrospectively enrolled 126 patients who were transported to our ER by ambulance with suspected stroke between April 15 and October 31, 2020 (study group). A risk judgment system named the COVID level was introduced to classify the risk of infection as follows : level 0, no infection ; I, infection unlikely ; II, possible ; III, probable ; and IV, definite. Patients with COVID levels 0, I, or II and a Glasgow Coma Scale (GCS) score >10 were placed in a normal ER (nER) without atmospheric pressure control ; the medical staff wore standard personal protective equipment (PPE) in such cases. Patients with COVID level II, III, or IV, and a GCS score of <-10 were assigned to the negative pressure ER (NPER) ; the medical staff wore enhanced PPE for these cases. The validity of the protocol was assessed. The door-to-picture time of the study group was compared with that of 114 control patients who were transported with suspected stroke during the same period in 2019 (control group). The difference in the time for CT and MRI between the two groups was also compared. In the study group, the time spent in the nER and NPER was evaluated. Results : In all, 118 patients (93.7%) were classified as level I, 6 (4.8%) as level II, and 2 (1.6%) as level III. Only five patients (4.0%) were treated with NPER. Polymerase chain reaction tests were performed on 118 out of 126 patients (93.7%) and were negative. No significant differences were observed in age, sex, neurological severity, modalities of diagnostic imaging, and diagnosis compared with the control group. The median door-to-picture time was 18 (11-27.8) min in the study group and 15 (10-25) min in the control group (p = 0.08). No delay was found on CT (15 10-21 vs. 14 9-21 min, p = 0.24). In contrast, there was an 8-min delay for MRI (30 21.8-50 vs. 22 14-30 min, p = 0.01). The median door-to-picture time was 29 min longer in patients treated with NPER than in those treated with nER, although the difference was not significant due to the small number of patients (47 27-57 vs. 18 11-26 min, p = 0.07). Conclusion : Our protocol could optimize the use of medical resources with only a 3-min delay in the door-to-picture time in an area without explosive outbreak. Unfortunately, the effectiveness of the protocol in preventing infection could not be verified because of the low incidence of COVID-19. When developing and modifying an institutional protocol, recognizing the outbreak status surrounding each institution is important.
Afferent loop syndrome is often difficult to resolve. Among patients with afferent loop syndrome whose data were extracted from databases, 5 patients in whom metal stent placement was attempted were ...included and evaluated in this study. The procedure was technically successful without any adverse events in all patients. Metal stent(s) was placed with an endoscope in the through-the-scope manner in 4 patients and via a percutaneous route in 1 patient. Obvious clinical efficacy was observed in all patients. Adverse events related to the procedure and stent occlusion during the follow-up period were not observed. Metal stent placement for malignant obstruction of the afferent loop was found to be safe and feasible. Clin Endosc 2018;51:299-303
Recessive dystrophic epidermolysis bullosa (RDEB) is caused by mutations in the gene encoding type VII collagen (COL7), a major component of anchoring fibrils in the epidermal basement membrane zone. ...Patients with RDEB present a low oral hygiene index and prevalent tooth abnormalities with caries. We examined the tooth enamel structure of an RDEB patient by scanning electron microscopy. It showed irregular enamel prisms, indicating structural enamel defects. To elucidate the pathomechanisms of enamel defects due to COL7 deficiency, we investigated tooth formation in Col7a1−/− and COL7-rescued humanized mice that we have established. The enamel from Col7a1−/− mice had normal surface structure. The enamel calcification and chemical composition of Col7a1−/− mice were similar to those of the wild type. However, transverse sections of teeth from the Col7a1−/− mice showed irregular enamel prisms, which were also observed in the RDEB patient. Furthermore, the Col7a1−/− mice teeth had poorly differentiated ameloblasts, lacking normal enamel protein–secreting Tomes' processes, and showed reduced mRNA expression of amelogenin and other enamel-related molecules. These enamel abnormalities were corrected in the COL7-rescued humanized mice expressing a human COL7A1 transgene. These findings suggest that COL7 regulates ameloblast differentiation and is essential for the formation of Tomes' processes. Collectively, COL7 deficiency is thought to disrupt epithelial–mesenchymal interactions, leading to defective ameloblast differentiation and enamel malformation in RDEB patients.
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