25 research outputs found

    Mechanical design of a convex-deformable polymer plate

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    The authorsā€™ previous study introduced a convex-deformable sandwich plate consisting of a pyramid truss core and two face sheets that exhibit a two-dimensional auxetic pattern. Owing to its unique micro-architecture, the sandwich plate successfully underwent adequate convex deformation under bending, even when many chips were embedded in its core. However, the plate was fabricated by adhesively bonding stainless-steel face sheets to a polymer truss core, and this fabrication process was complex and expensive. Moreover, the detailed dimensions of this plate were determined iteratively through trial-and-error. In this study, we develop a fresh approach to monolithically fabricate the entire body of the auxetic plate from a polymer by using three-dimensional printing. First, three mechanical constraints, which are needed for designing the face sheets and the core to realize compliant and convex deformation, unlike that of an ordinary sandwich plate, are defined. A precise mechanical design procedure is applied for dimensional optimization of the plate, and the mechanical behaviors of the fabricated specimen are observed by subjecting it to tensile and bending loads. The optimally designed polymer specimen exhibited a high level of convex deformation, as indicated by its adequate flexural rigidity (DĀ =Ā 0.0565 Nm2) and curvature ratio (0.625) when bent to the minimum curvature radius of ĻĀ =Ā 150Ā mm

    Multiple Myeloma in a Patient with Acromegaly

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    Acromegaly is a slowly progressing condition resulting from excess growth hormone (GH), generally caused by a GH-secreting pituitary adenoma. Cancer is the third most common cause of mortality in patients with acromegaly, and insulin-like growth factor 1 (IGF-1) is known to influence tumor formation by increasing cell proliferation and inhibiting apoptosis. Multiple myeloma (MM) is a plasma cell neoplasm, and previous studies have suggested the possible role of IGF-1 in its development of MM. However, no cases of acromegaly accompanied with MM have been reported in Asia to date. We here report the case of a 58-year-old woman with acromegaly accompanied with MM who presented with longstanding acromegalic manifestations resulting from a GH-secreting pituitary adenoma and also exhibited anemia, a reversed albumin/globulin ratio, and plasmacytosis on bone marrow examination. Because IGF-1 has been suggested to play an important role in the development and progression of MM, the patient promptly underwent surgical removal of the pituitary adenoma via a transsphenoidal approach. Since there is currently no consensus on therapeutic guidelines and suggested prognosis for MM with acromegaly, long-term follow-up of such cases is needed

    An Ultralight Capillary-Driven Heat Pipe

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    Capillary-driven heat pipes are an effective thermal solution for compacting electronic cooling systems. We advance such a heat pipe thermal solution with ultralightweighting for mobile applications. In our advancement, the envelope that encapsulates the phase-change process of a working fluid is fabricated via electroless plating being āˆ¼40 Ī¼m thick. Furthermore, the wick structure that transports condensate to a heat source via capillarity is also electroless-plated onto the envelopeā€™s inner surfaces, creating a 100-Ī¼m-thick, microporous layer. This wick structure is sequentially superhydrophilized by blackening that forms a nanotexture on the microporous wick layer. An effective density of our prototype ultralight heat pipes (uHPs), as a measure of lightweighting, indicates, on average, a remarkable 73% weight reduction of commercial counterparts with sintered copper powder wick in similar exterior dimensions (e.g., āˆ¼2.7 g, compared to āˆ¼10.0 g) while providing equivalent heat spreading. Furthermore, the uHP operates at a 25% lower evaporator temperature, due to additional heat rejection to the surroundings through the ultrathin-walled envelope and wick

    Chronic intractable diarrhea caused by gastrointestinal mastocytosis

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    As mast cells have been highlighted in the pathogenesis of diarrhea-predominant irritable bowel syndrome, a new term "mastocytic enterocolitis" was suggested by Jakate and colleagues to describe an increase in mucosal mast cells in patients with chronic intractable diarrhea and favorable response to treatment with antihistamines. Although it is not an established disease entity, two cases have been reported in the English medical literature. Here, for the first time in Asia, we report another case of chronic intractable diarrhea caused by gastrointestinal mastocytosis. The patient was a 70-year-old male with chronic intractable diarrhea for 3 months; the cause of the diarrhea remained obscure even after exhaustive evaluation. However, biopsy specimens from the jejunum were found to have increased mast cell infiltration, and the patient was successfully treated with antihistamines

    Clinical Outcomes of Angiography and Transcatheter Arterial Embolization for Acute Gastrointestinal Bleeding: Analyses according to Bleeding Sites and Embolization Types

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    Background/Aims: The clinical outcomes of angiography and transcatheter arterial embolization (TAE) for acute gastrointestinal bleeding (GIB) have not been completely assessed, especially according to bleeding sites. This study aimed to assess the efficacy of angiography and safety of TAE in acute GIB. Methods: This was a retrospective study evaluating the records of 321 patients with acute GIB who underwent angiography with or without TAE. Targeted TAE was conducted in 134 patients, in whom angiography showed bleeding sources. Prophylactic TAE was performed in 29 patients when the bleeding source was not detected but a specific vessel was strongly suspected by other examinations. The rate of technical success, clinical success, and complications were analyzed. Results : The detection rate of bleeding source via angiography was 50.8% (163/321), which was not different according to the bleeding sites. The detection rate was higher if the probable bleeding source had already been found by another investigation (59.7% vs. 35.8%, p<0.001). TAE sites were upper GIB in 67, mid GIB in 74, and lower GIB in 22. The technical success rate was 99.3% (133/134), and the clinical success rate was 63.0% (104/163). The prophylactic embolization group showed lower clinical success rate than the targeted embolization group (44.8% vs. 67.9%, p=0.06). The TAE-related complication rate was 12.9% (21/163). Ischemia and/or infarction was more common after TAE for mid and lower GIB than for upper GIB (15.6% vs. 3.0%, p=0.007). Conclusions: Angiography with or without TAE was an effective method for acute GIB. Targeted embolization should be performed if possible given that it has a higher clinical success rate

    Fecal calprotectin predicts complete mucosal healing and better correlates with the ulcerative colitisĀ endoscopic index of severity than with the Mayo endoscopic subscore in patients with ulcerative colitis

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    Abstract Background We aimed to evaluate the role of fecal calprotectin (FC) as a noninvasive marker for the disease activity of ulcerative colitis (UC) in a Korean cohort. Methods A total of 181 fecal samples were collected from 181 consecutive UC patients between April 2015 and September 2016. FC levels were measured using the Quantum BlueĀ® Calprotectin rapid test. The laboratory test results, partial Mayo Score (pMS), and colonoscopic imaging findings at FC level measurement were retrospectively reviewed. The Mayo endoscopic subscore (MES) and UC endoscopic index of severity (UCEIS) were graded by 2 certified endoscopists after training with 50 other cases. Results The FC levels were significantly correlated with pMS (Spearman correlation coefficient rĀ =Ā 0.428, pĀ <Ā 0.001), MES (rĀ =Ā 0.304, pĀ <Ā 0.001), UCEIS (rĀ =Ā 0.430, pĀ <Ā 0.001), and CRP (rĀ =Ā 0.379, pĀ <Ā 0.001). FC levels exhibited a significantly better correlation with UCEIS than with MES (Mengā€™s zĀ =Ā āˆ’ 2.457, pĀ =Ā 0.01). The FC cut-off level of 187.0Ā mg/kg indicated complete mucosal healing (MESĀ =Ā 0; UCEIS =0) with a sensitivity and specificity of 0.857 and 0.891, respectively (area under the curve, 0.883; 95% confidence interval, 0.772ā€“1.000). Conclusion The FC level is significantly correlated with the clinical disease activity index, endoscopic indices, and serum inflammatory biomarkers in a Korean UC cohort. FC is highly predictive of complete mucosal healing in UC. UCEIS exhibits a stronger correlation with the FC level, as compared to MES. Thus, FC could be used as a reliable noninvasive indicator for evaluating disease activity and mucosal healing in UC
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