452 research outputs found

    Charge Storage in Organic Electrodes for Energy & Electrochemical Applications

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    Energy storage has been emerging as an important research topic because of the lack of fossil fuels and growing energy consumption. This thesis focuses on synthesis and characterization of electrode materials such as polyaniline, graphene, and nitrogen-doped porous carbon for use in energy storage applications. Polyaniline (PANI), a conjugated polymer, has been widely investigated as an electrode material for energy storage. In order to enhance its oxidative stability, polyaniline:poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PANI:PAAMPSA) complex was synthesized using template polymerization. PANI:PAAMPSA possessed significantly increased oxidative stability up to 4.5 V (vs. Li/Li+) due to electrostatic and hydrogen bonding interactions between PANI and PAAMPSA. This polyacid-doped PANI showed a reversible capacity of 230 mAh/gPANI for over 800 cycles. Three different polyaniline-based layer-by-layer (LbL) electrodes, PANI/PAAMPSA, PANI/PANI:PAAMPSA, and linear poly(ethylenimine)/PANI:PAAMPSA were fabricated and their charge storage natures were assessed in non-aqueous energy storage systems. PANI:PAAMPSA retained its oxidative stability within LbL electrodes. The PANI/PAAMPSA LbL electrode did not show enhanced oxidative stability as compared to PANI:PAAMPSA complexes, which indicates that the interactions between PANI and PAAMPSA are not as strong as in PANI:PAAMPSA complexes. Porous PANI nanofiber/graphene hybrid electrodes were prepared by electrochemical reduction of PANI nanofiber/graphene oxide (PANI NF/GO) LbL assemblies at 1.5 V (vs. Li/Li+). The limited processibility of reduced graphene oxide was circumvented by using GO to build up PANI NF/GO LbL films followed by electrochemical reduction. PANI NF/electrochemically reduced graphene oxide (ERGO) LbL electrodes show high capacity and enhanced cycling stability. Its performance is strongly dependent on electrode thickness. Nitrogen-doped porous carbon was synthesized by one-step carbonization of isorecticular metal-organic frameworks (IRMOF-3). Porous IRMOF-3 itself acts as a self-sacrificial template to provide porous structure. Furthermore, additional carbon and nitrogen sources were not required. The nitrogen content can be easily controlled by varying carbonization temperature. Nitrogen-doped porous carbon possessed significantly higher capacitance due to additional pseudocapacitance originating from nitrogen as compared to analogous nitrogen-free porous carbons

    Effects of a Tumor Necrosis Factor-α Antagonist on Experimentally Induced Rhinosinusitis

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    This prospective, randomized, and controlled study examined the effects of tumor necrosis factor soluble receptor type I (sTNFRI, a TNF-α antagonist) on experimentally induced rhinosinusitis in rats. The experimental groups received an instillation of lipopolysaccharide (LPS) plus an intramuscular injection of amoxicillin/clavulanate (antibiotic group), an instillation of sTNFRI (sTNFRI group), an instillation of sTNFRI and an injection of amoxicillin/clavulanate (sTNFRI/antibiotic group), or no additional treatment (LPS group). Histopathological changes were determined using hematoxylin-eosin and periodic acid-Schiff (PAS) staining. Leakage of exudate was determined using fluorescence microscopy. Vascular permeability was measured using the Evans blue dye technique. Expression of MUC5AC was measured using reverse transcriptase PCR. The sTNFRI, antibiotic, and sTNFRI/antibiotic groups had significantly less capillary permeability, mucosal edema, PAS staining, and expression of MUC5AC than the LPS group. There were no differences in capillary permeability, mucosal edema, PAS staining, and MUC5AC expression between the sTNFRI and sTNFRI/antibiotic groups. The antibiotic group had PAS staining similar to that of the sTNFRI and sTNFRI/antibiotic groups but had a greater increase in capillary permeability, mucosal edema, and MUC5AC expression. This study shows that sTNFRI reduces inflammatory activity and mucus hypersecretion in LPS-induced rhinosinusitis in rats

    Ectopic Hidradenoma Papilliferum of the Breast: Ultrasound Finding

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    Hidradenoma papilliferum (HP) is a benign neoplasm arising from mammary-like glands which typically involves the dermal layer of the female anogenital area. The prognosis for HP is good. Recurrence is unusual and is typically attributed to incomplete excision of the primary tumor. Malignant transformation is rare and HP of the breast has not yet been reported. Ectopic HP is usually solitary, small, and asymptomatic. It appears as a well-circumscribed, complex cystic mass in the dermis on ultrasound. We present a case of HP arising from the axillary tail of the breast

    Primary Osteosarcoma Arising from the Middle Turbinate in a Pediatric Patient

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    Osteosarcomas usually occur as secondary tumors after radiation therapy or chemotherapy. Without a history of irradiation to the head and neck area, primary osteosarcoma of the turbinate is extremely rare. We report here a rare case of primary turbinate osteosarcoma presenting as a relatively small, well-circumscribed, turbinate mass. Its appearance mimicked a benign nasal mass like mucocele and polyp. We also reviewed the previously reported cases of tumor arising from turbinate

    Successful Hemostasis with Recombinant Activated Factor VII in a Patient with Massive Hepatic Subcapsular Hematoma

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    Recombinant activated coagulation factor VII (rFVIIa) is known to be effective in the management of acquired deficiencies of factor VII and platelet function defects. But recently, rFVIIa has been successfully used to treat ongoing bleeding in disseminated intravascular coagulopathy (DIC) condition. The patient reported here was suspected to be suffering from toxic hepatitis on admission. After percutaneous liver biopsy, bleeding occurred and did not stop even after right hepatic artery embolization. The patient developed a severe hemorrhage that resulted in hypovolemic shock, hemoperitoneum, and a massive subcapsular hematoma. The patient then developed DIC due to massive transfusion, as well as acute liver necrosis. The patient was given 400 μg/kg of rFVIIa. Recombinant factor VIIa was administered in an attempt to control the bleeding. This stabilized the hemoglobin levels of the patient. The patient gradually recovered in 4 months. In conclusion, this case suggests that rFVIIa can be successfully used for the hemostasis of uncontrolled bleeding in DIC

    Pseudoaneurysm of the popliteal artery mimicking tumorous condition

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    Diagnosing pseudoaneurysms of the popliteal artery is usually straightforward in physical examinations and imaging findings. However, when a pseudoaneurysm shows a soft tissue mass with adjacent osseous change, it can mimic a bone tumor or a soft tissue sarcoma. We present a case of a 65-year-old man who had a pseudoaneurysm of the popliteal artery showing soft tissue mass and insinuating into the intramedullary cavity of the tibia. This presented case emphasizes the importance of considering pseudoaneurysms in the differential diagnosis of an apparent soft tissue mass with pressure erosion in adjacent bone

    The Value of Procalcitonin and the SAPS II and APACHE III Scores in the Differentiation of Infectious and Non-infectious Fever in the ICU: A Prospective, Cohort Study

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    Early and accurate differentiation between infectious and non-infectious fever is vitally important in the intensive care unit (ICU). In the present study, patients admitted to the medical ICU were screened daily from August 2008 to February 2009. Within 24 hr after the development of fever (>38.3℃), serum was collected for the measurement of the procalcitonin (PCT) and high mobility group B 1 levels. Simplified Acute Physiology Score (SAPS) II and Acute Physiology And Chronic Health Evaluation (APACHE) III scores were also analyzed. Sixty-three patients developed fever among 448 consecutive patients (14.1%). Fever was caused by either infectious (84.1%) or non-infectious processes (15.9%). Patients with fever due to infectious causes showed higher values of serum PCT (7.8±10.2 vs 0.5±0.2 ng/mL, P=0.026), SAPS II (12.0±3.8 vs 7.6±2.7, P=0.006), and APACHE III (48±20 vs 28.7±13.3, P=0.039) than those with non-infectious fever. In receiver operating characteristic curve analysis, the area under the curve was 0.726 (95% CI; 0.587-0.865) for PCT, 0.759 (95% CI; 0.597-0.922) for SAPS II, and 0.715 (95% CI; 0.550-0.880) for APACHE III. Serum PCT, SAPS II, and APACHE III are useful in the differentiation between infectious and non-infectious fever in the ICU
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