Sung-Yoon Kang

Conditional moment closure and transient flamelet modelling for detailed structure and NOx formation characteristics of turbulent nonpremixed jet and recirculating flames

This study has been mainly motivated to assess computationally and theoretically the conditional moment closure (CMC) model and the transient flamelet model for the simulation of turbulent nonpremixed flames. These two turbulent combustion models are implemented into the unstructured grid finite volume method that efficiently handles physically and geometrically complex turbulent reacting flows. Moreover, the parallel algorithm has been implemented to improve computational efficiency as well as to reduce the memory load of the CMC procedure. Example cases include two turbulent CO/H2/N2 jet flames having different flow timescales and the turbulent nonpremixed H2/CO flame stabilized on an axisymmetric bluff-body burner. The Lagrangian flamelet model and the simplified CMC formulation are applied to the strongly parabolic jet flame calculation. On the other hand, the Eulerian particle flamelet model and full conservative CMC formulation are employed for the bluff-body flame with flow recirculation. Based on the numerical results, a detailed discussion is given for the comparative performances of the two combustion models in terms of the flame structure and NO x formation characteristics.

Hypersensitivity Reactions to Oxaliplatin: Clinical Features and Risk Factors in Koreans

BACKGROUND AND AIM Oxaliplatin hypersensitivity is a well-known adverse reaction but the prevalence varies and data for frequency and clinical features have not been reported for Korea. Here we evaluates the prevalence and risk factors for hypersensitivity reactions to oxaliplatin after chemotherapy. METHODS Clinical information on all patients treated with oxaliplatin was retrospectively reviewed in electronic medical records between August 2009 and July 2010 in Seoul National University Bundang Hospital. Patients who experienced hypersensitivity reactions to oxaliplatin were compared with those who did not. RESULTS A total of 393 patients received oxaliplatin, with 42 (10.7%) experiencing hypersensitivity reactions including three cases of anaphylaxis. Median cycle of the first hypersensitivity reaction was 8. Reactions correlated with lower dexamethasone doses. Other variables were not significant. CONCLUSIONS The prevalence of hypersensitivity reactions was 10.7%, symptoms being mostly mild and cutaneous. Lower dexamethasone doses could be a predictor for hypersensitivity reactions to oxaliplatin.

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms syndrome induced by cilostazol and carbamazepine.

Dear Editor, A 54-year-old man presented with a fever and a maculopapular rash on his trunk, extremities and face. At the time of admission, he was taking an inhaled corticosteroids ⁄ long-acting b-agonist combination for bronchial asthma, carbamazepine (CBZ) for peripheral neuropathy (for 2 weeks), and triple antiplatelet therapy (cilostazol, aspirin and clopidogrel) due to coronary stent placement approximately 3 months prior. One week before admission, he developed fever, myalgia and skin eruptions. At admission, his temperature was 38.0 C, and he had a maculopapular rash on his trunk and extremities. Exfoliative dermatitis also observed on his face. Laboratory tests revealed a leukocytosis (27 060 ⁄ mm) with eosinophilia (1802 ⁄ mm). C-reactive protein was 2.18 mg ⁄ dL and erythrocyte sedimentation rate was 6 mm ⁄ h for the first hour. Liver function tests revealed cytolytic hepatitis (aspartate aminotransferase 46 UI ⁄ L, alanine aminotransferase 50 UI ⁄ L). Markers for hepatitis A, B and C virus were negative. Human herpesvirus 6 (HHV-6) DNA polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay test for parasitic infections were negative. Culture of blood and urine, and parasitological examination of feces showed no infection. Autoantibody screens (antinuclear and antineutrophil cytoplasmic antibodies) were negative. A histological examination of a skin biopsy showed interface dermatitis with superficial perivascular lymphocytic infiltration (Fig. 1). The diagnosis of drug-induced hypersensitivity syndrome (DIHS) ⁄ drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome was proposed on the basis of his clinical and laboratory findings. All medications were promptly discontinued, and high dose corticosteroid (methylprednisolone 1 mg ⁄ kg daily, i.v.) was initiated. His general condition, including the skin lesion and

Diagnostic accuracy of fractional exhaled nitric oxide measurement in predicting cough-variant asthma and eosinophilic bronchitis in adults with chronic cough: A systematic review and meta-analysis

Background Individual studies have suggested the utility of fractional exhaled nitric oxide (Feno) measurement in detecting cough‐variant asthma (CVA) and eosinophilic bronchitis (EB) in patients with chronic cough. Objective We sought to obtain summary estimates of diagnostic test accuracy of Feno measurement in predicting CVA, EB, or both in adults with chronic cough. Methods Electronic databases were searched for studies published until January 2016, without language restriction. Cross‐sectional studies that reported the diagnostic accuracy of Feno measurement for detecting CVA or EB were included. Risk of bias was assessed with Quality Assessment of Diagnostic Accuracy Studies 2. Random effects meta‐analyses were performed to obtain summary estimates of the diagnostic accuracy of Feno measurement. Results A total of 15 studies involving 2187 adults with chronic cough were identified. Feno measurement had a moderate diagnostic accuracy in predicting CVA in patients with chronic cough, showing the summary area under the curve to be 0.87 (95% CI, 0.83‐0.89). Specificity was higher and more consistent than sensitivity (0.85 [95% CI, 0.81‐0.88] and 0.72 [95% CI, 0.61‐0.81], respectively). However, in the nonasthmatic population with chronic cough, the diagnostic accuracy to predict EB was found to be relatively lower (summary area under the curve, 0.81 [95% CI, 0.77‐0.84]), and specificity was inconsistent. Conclusions The present meta‐analyses indicated the diagnostic potential of Feno measurement as a rule‐in test for detecting CVA in adult patients with chronic cough. However, Feno measurement may not be useful to predict EB in nonasthmatic subjects with chronic cough. These findings warrant further studies to validate the roles of Feno measurement in clinical practice of patients with chronic cough.

A Multi-Mode Multi-Band Reconfigurable Power Amplifier for 2G/3G/4G Handset Applications

Fully-integrated multi-mode multi-band (MMMB) reconfigurable power amplifier (PA) is implemented using single PA-cores for high- and low-frequency bands, respectively. This PA has five output paths and covers quad-band Gaussian Minimum Shift Keying/Enhanced Data Rates for Global Evolution and penta-band Universal Mobile Telecommunications System/Long Term Evolution mode operation with band combination in a small form-factor. To optimize the PA, the proposed structure reconfigures the PA-core cells as well as the interstage/output matching network. When compared with the single-mode single-band dedicated PAs, the fabricated PA showed comparable RF performance for all modes and bands, except for PAE degradations of 3.1% and 1.9% for high- and low-band, respectively, thus validating the usefulness of the proposed structure for MMMB PA applications.

A multi-mode multi-band reconfigurable power amplifier for low band GSM/UMTS handset applications

A practical reconfigurable structure for multi-mode multi-band (MMMB) reconfigurable power amplifier (PA) is proposed for GSM/UMTS handset applications. To overcome not only the frequency difference (MB) but also the power difference (MM) between GSM and UMTS standards, the proposed structure reconfigures the PA core as well as the output matching network. To verify the performance of the proposed structure, a MMMB PA is developed for GSM/EDGE/UMTS low-frequency bands applications. The fabricated MMMB PA showed good RF performance for UMTS as well as GSM/EDGE applications. Efficiency degradation was limited to less than 2% compared to the single-mode single-band PA. Measured RF performance validates the usefulness of the proposed structure for MMMB applications.

Isopropyl alcohol decomposition over molybdena-alumina catalyst

The decomposition of isopropyl alcohol was chosen as a probe reaction of acid-base property of molybdena-alumina catalyst. The catalytic kinetics was examined on the oxidized catalyst. The kinetics of the dehydration (yielding propene) and the dehydrogenation (yielding acetone) obeyed the Langmuir-Hinshelwood mechanism in which the rate determining step is the desorption of water for the former and the sur face reaction for the latter, respectively. The effect of varying the extent of reduction of the catalyst was also studied. The trend of variation with the reduction was fairly consistent with the surface chemistry of the catalyst.

Intravenous tacrolimus and cyclosporine induced anaphylaxis: what is next?

Tacrolimus and cyclosporine have been used in various formulations, but their hypersensitivity reactions are rare in practice. Castor oil derivatives are nonionic surfactants used in aqueous preparations of hydrophobic active pharmaceutical ingredients. Castor oil derivatives that can be used as additives to tacrolimus and cyclosporine may play a role in the development of hypersensitivity reactions, especially anaphylaxis. Various immunologic and nonimmunologic mechanisms have been implicated in hypersensitivity reactions induced by castor oil derivatives. Physicians should be aware that not only the drug itself, but also its additives or metabolites could induce hypersensitivity reactions. We report a case of anaphylaxis caused by vitamin K (phytonadine), serotonin antagonist (granisetron), intravenous tacrolimus, and cyclosporine. Interestingly, the patient tolerated oral cyclosporine, which did not contain Cremophor EL or polysorbate 80.

Chronic cough in Korean adults: a literature review on common comorbidity

Chronic cough is a significant medical condition with high prevalence and a strong negative impact on the quality of life. Cough hypersensitivity is thought to underlie chronic cough, with several environmental and host factors interacting to cause neuronal sensitization and chronicity. Comorbid conditions affecting cough reflex pathways, such as upper airway diseases, asthma, and gastroesophageal reflux, play important roles in chronic cough. However, their prevalence may vary in patients living in different geographical regions or with different ethnicities. We conducted a literature review to examine common comorbidities in Korean adult patients with chronic cough, their clinical implications, and the issues that still need to be addressed in the development of clinical evidence of chronic cough in Korean adult patients.

A Case of Trimebutine-Induced Anaphylaxis

Trimebutine maleate [2-dimethylamino-2-phenylbutyl 3,4,5-trimethoxybenzoic acid] has been demonstrated to be active for relieving abdominal pain and it is widely used for patients with irritable bowel syndrome. Adverse drug reactions are mostly mild and well-tolerated. To our knowledge, only two cases of trimebutine induced hypersensitivity have been reported, and both were delayed type reactions. Here, we report the first case of trimebutine maleate-induced anaphylaxis.