20 research outputs found

    A new heat propagation velocity prevails over Brownian particle velocities in determining the thermal conductivities of nanofluids

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    An alternative insight is presented concerning heat propagation velocity scales in predicting the effective thermal conductivities of nanofluids. The widely applied Brownian particle velocities in published literature are often found too slow to describe the relatively higher nanofluid conductivities. In contrast, the present model proposes a faster heat transfer velocity at the same order as the speed of sound, rooted in a modified kinetic principle. In addition, this model accounts for both nanoparticle heat dissipation as well as coagulation effects. This novel model of effective thermal conductivities of nanofluids agrees well with an extended range of experimental data

    The Thermophysical Roll of Nanoparticles in Nanofluidic Heat and Mass Transport

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    Nanofluids are colloids that consist of a base fluid and nanometer sized metallic particles, which serve to improve the heat and mass transport characteristics of nanofluids over those of the base fluid. Many researchers, attracted to the highly enhanced thermal conductivity, have studied nanofluids, and yet have never been able to reveal the basic mechanisms of their characteristic improvements. This present work thus seeks to gain an understanding of the role of nanoparticles in nanofluidic heat and mass transport characteristics through three experimental measurements: 1) thermal conductivity measurement, 2) thermophoretic motion measurement, and 3) evaporation measurement. Using thermal conductivity, thermophoresis, and evaporation measurements of nanofluids, nanofluidic heat and mass transport has been studied, thermal conductivity model has been derived, and the roles of nanoparticles in nanofluids have been revealed. Thus, the present work contributes specifically towards an understanding of the fundamental role of nanoparticles in the heat and mass transport of nanofluids and generally towards the use nanofluids in heat and mass transport applications

    Budd-Chiari syndrome presenting with abdominal wall varices

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    A microfluidic application for mass production of drug-loaded polymeric microspheres for a long-acting injectable with IVL-DrugFluidicĀ®, a novel microfluidic microsphere manufacturing platform technology

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    Long acting injectables (LAIs) using polymeric microspheres has been developed to increase patient compliance and reduce side effects. Among many methods for manufacturing polymeric microspheres, microfluidics technology is known to have excellent characteristics in that the produced polymeric microspheres have perfect spherical shape without surface defect and uniform size, and thus have outstanding efficacy without initial burst. However, the mass production of polymeric microspheres was not realized by the inherent limitation that microfluidics is suitable for small quantity manufacturing. Overcoming such limitations, we could show mass production of finasteride-loaded polymeric microspheres (PLGA 7525) for LAIs using our microfluidic manufacturing platform technology, IVL-DrugFluidicĀ®. The microfluidic channels used in manufacturing were optimized through computational fluid dynamics (CFD) simulation to minimize the flow variation between microchannels and eliminated disturbance outside of microchannels by resistance channels. In addition, the solvent removal was improved by applying the baffle and foam breaker system. Therefore, microspheres were mass-produced in the GMP manufacturing environment in perfect spherical shape, smooth surface, and even size distribution. The encapsulation efficiency was almost 100% and the residual solvent was under the Standard of regulation. In the clinical trial using microspheres mass-produced by IVL-DrugFluidicĀ®, we confirmed that the drug release was stably maintained for a month, the target period without initial burst. It was also confirmed that the drug release by dose of microspheres was uniformly proportional. In conclusion, the microsphere manufacturing platform technology, IVL-DrugFluidicĀ® has been proven to be an appropriate system for mass production of polymeric microspheres optimized for LAIs through physicochemical characteristics and clinical trial

    Uncovering the clinicopathological features of early recurrence after surgical resection of pancreatic cancer

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    Abstract To identify risk factors and biomarker for early recurrence in patients diagnosed with pancreatic cancer who undergo curative resection. Early recurrence after curative resection of pancreatic cancer is an obstacle to long-term survival. We retrospectively reviewed 162 patients diagnosed with pancreatic cancer who underwent curative resection. Early recurrence was defined as recurrence within 12Ā months of surgery. We selected S100A2 as a biomarker and investigated its expression using immunohistochemistry. Of the total, 79.6% (nā€‰=ā€‰129) of patients received adjuvant chemotherapy after surgery and 117 (72.2%) experienced recurrence, of which 73 (45.1%) experience early recurrence. In multivariate analysis, ageā€‰ā€‰5) was significantly lower in the early recurrence group (41.5% vs. 63.3%, Pā€‰=ā€‰0.020). The cumulative incidence rate of early recurrence was higher in patients with an S100A2 H-scoreā€‰<ā€‰5 (41.5% vs. 63.3%, Pā€‰=ā€‰0.012). The median overall survival of patients with higher S100A2 expression was longer than those with lower S100A2 expression (median 30.1Ā months vs. 24.2Ā months, Pā€‰=ā€‰0.003). High-risk factors for early recurrence after surgery for pancreatic cancer include young age, lymph node metastasis, and no adjuvant therapy. Neoadjuvant treatment or intensive adjuvant therapy after surgery may improve the prognosis of patients with high-risk signatures. In patients who receive adjuvant therapy, high S100A2 expression is a good predictor

    A Case of Possible Neurosarcoidosis Presenting as Intractable Headache and Panhypopituitarism

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    Sarcoidosis is a chronic multisystemic inflammatory disease of unknown etiology, which is characterized by noncaseating granulomatous inflammation of the involved organs. It is known that neurosarcoidosis involving the nervous system occurs in about 5% of patients with sarcoidosis. However, neurosarcoidosis without systemic involvement is extremely rare. We present a case of suspicious neurosarcoidosis affecting the pituitary gland, which was manifested as chronic uncontrolled headache, panhypopituitarism, central diabetes insipidus, and hypercalcemia. Though the biopsy at the pituitary lesion was not performed due to the high risk of surgical complication, treatment was needed urgently and we started steroid therapy. After steroid therapy, we observed the immediate symptom relief with improved hypercalcemia. According to the follow-up examination, no recurrent symptom was seen, and resolution of the pituitary lesion with improving panhypopituitarism was noted
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