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The nanoscopic characteristics of the multi-walled carbon nanotubes (MWCNTs) used in composites are crucial for attempting to understand and design nanocomposites of a novel class. We investigate the correlations between the nanofiller properties and effective electrical properties of MWCNT-embedded polycarbonate composites by theoretical and experimental approaches. A probabilistic computational model is proposed to predict the influence of MWCNT morphology on the electrical behaviors of MWCNTs-embedded polymer composites. A parameter optimization method in accordance with a genetic algorithm is then applied to the model, resulting that the ideal sets of model constant for the simulation are computationally estimated. For the experimental validation purpose, a comparison between the present theoretical and experimental results is made to assess the capability of the proposed methods. In overall, good agreement between the predictions and experimental results can be observed and the electrical performance of the composites can be improved as the MWCNT length increases.

Polypropylene-grafted-maleic anhydride (PP-g-MAH) is known as an excellent interface modifier that can improve the interface between carbon fiber (CF) and PP. In this study, the effect of PP-g-MAH content on the physical properties of PP composites containing long-fiber CFs was investigated. It was confirmed that PP-g-MAH acted as an interface modifier between the interface between CF and PP, and when an appropriate amount of 10 wt% was incorporated, the tensile strength, tensile modulus, Izod impact strength, and heat deflection temperature were improved by 110%, 50%, 86.7% and 12.7%, respectively. On the other hand, the blending effect of PP-g-MAH, which is a low molecular weight, was greater than the compatibilizing effect when the PP-g-MAH content was mixed above the appropriate content, thereby reducing the physical properties. Therefore, the content of PP-g-MAH as the interface modifier must be designed to be the optimum content considering the CF content to be mixed in order to optimize the physical properties of the composite material.

Invasive mucormycosis is an uncommon but increasing life-threatening fungal infection. The present study investigated clinical characteristics and mortality among patients diagnosed as invasive mucormycosis infection. We retrospectively reviewed a total of 24 histologically proven cases of invasive mucormycosis at two tertiary care referral hospitals between November 2005 and February 2014. Overall survival was 50% (n = 12). The time between onset of symptom and diagnostic procedure proved to be associated with mortality (P = 0.009). In addition, preexisting renal failure and thrombocytopenia demonstrated trends toward a poor outcome in our study (P = 0.089 and 0.065, respectively). On multivariate regression analysis, delayed diagnostic procedure (more than 16 days after the onset of symptoms) was an independent predictor of mortality (OR= 12.34, 95% CI, 1.43-10.64; P = 0.022). Mucormycosis is a destructive fungal infection that is associated with high mortality rates, ranging from 40% to 100% depending on the form of disease. When a clinician suspects invasive mucormycosis infection, an early diagnostic procedure performed within 16 days from the onset of symptom and early initiation of antifungal therapy will lead to successful management of this highly fatal disease.

With the recent demand for miniaturization and integration of electronic devices, there has been a growing interest in device malfunction due to high temperature. In this study, a experimental and theoretical study on the composites with improved thermal conductivity by dispersing multi-walled carbon nanotubes (MWCNTs) in the thermoplastic resin was carried out. A micromechanical model was derived based on the ensemble volume-averaging method and the modified Eshelby’s tensor reflecting the interface properties. The effects of the waviness, interface, and orientation of fillers on the thermal conductivity of composites were numerically analyzed. A computational intelligence-based particle swarm optimization (PSO) algorithm was adopted to the proposed model for optimizing the model constants. The thermal conductivity of the polymerized cyclic butylene terephthalate (pCBT)/MWCNT composites was experimentally measured according to the content of MWCNT. Finally, the experimentally measured data were utilized in the PSO to improve the predictive capability of the proposed model.

In order to develop a nanocomposite film based on multi-walled carbon nanotubes (MWCNTs) as an electromagnetic wave shielding material, we propose a solvent-free melting process for fabricating highly dispersed MWCNT-filled polymer composite films with high electrical conductivity and electromagnetic interference (EMI)-shielding properties. By observing aggregates (particles larger than 0.7 μm) using X-ray micro-computed tomography (micro-CT), the uniform dispersion of the MWCNT fillers in the composite films was confirmed. Furthermore, the electrical conductivity and EMI shielding effectiveness (SE) values calculated using percolation and Simon's equations, respectively, were confirmed to agree with experimental data, indicating excellent MWCNT dispersion. The fabricated composites exhibited excellent electrical conductivity, EMI SE, and EMI specific SE (SSE) values of 4.33 S/cm, 30 dB, and of 24.8 dBcm3g−1, respectively, and the EMI SSE value was as good as metal levels. The proposed solvent-free process can be contributed to the commercialization of EMI SE composite films based on MWCNTs.

There is growing interest in carbon fibre fabric reinforced polymer (CFRP) composites based on a thermoplastic matrix, which is easy to rapidly produce, repair or recycle. To expand the applications of thermoplastic CFRP composites, we propose a process for fabricating conductive CFRP composites with improved electrical and thermal conductivities using an in-situ polymerizable and thermoplastic cyclic butylene terephthalate oligomer matrix, which can induce good impregnation of carbon fibres and a high dispersion of nanocarbon fillers. Under optimal processing conditions, the surface resistivity below the order of 10+10 Ω/sq, which can enable electrostatic powder painting application for automotive outer panels, can be induced with a low nanofiller content of 1 wt%. Furthermore, CFRP composites containing 20 wt% graphene nanoplatelets (GNPs) were found to exhibit an excellent thermal conductivity of 13.7 W/m·K. Incorporating multi-walled carbon nanotubes into CFRP composites is more advantageous for improving electrical conductivity, whereas incorporating GNPs is more beneficial for enhancing thermal conductivity. It is possible to fabricate the developed thermoplastic CFRP composites within 2 min. The proposed composites have sufficient potential for use in automotive outer panels, engine blocks and other mechanical components that require conductive characteristics.

The anisotropic development of thermal conductivity in polymer composites was evaluated by measuring the isotropic, in-plane and through-plane thermal conductivities of composites containing length-adjusted short and long multi-walled CNTs (MWCNTs). The thermal conductivities of the composites were relatively low irrespective of the MWCNT length due to their high contact resistance and high interfacial resistance to polymer resins, considering the high thermal conductivity of MWCNTs. The isotropic and in-plane thermal conductivities of long-MWCNT-based composites were higher than those of short-MWCNT-based ones and the trend can accurately be calculated using the modified Mori-Tanaka theory. The in-plane thermal conductivity of composites with 2 wt% long MWCNTs was increased to 1.27 W/m·K. The length of MWCNTs in polymer composites is an important physical factor in determining the anisotropic thermal conductivity and must be considered for theoretical simulations. The thermal conductivity of MWCNT polymer composites can be effectively controlled in the processing direction by adjusting the length of the MWCNT filler.

Endobronchial actinomycosis is a rare but important and challenging diagnosis to make. We report a case of 57 year-old man who presented with a fever and a right-sided chest pain diagnosed as an endobronchial actinomycosis. Chest computed tomography showed a segmental obstruction and consolidations in right middle lobe combined with an ipsilateral multiloculated pleural effusion. Bronchoscopic biopsy of a mass obstructing the medial segmental bronchus of right middle lobe revealed actinomycosis. This is the first reported case of primary endobronchial actinomycosis that presented with a chest pain and a complicated parapneumonic effusion. Primary endobronchial actinomycosis can be a cause of complicated parapneumonic effusion.

Background/Aims As the incidence rate of and mortality from pseudomembranous colitis (PMC) are increasing worldwide, it is important to study the simple predictive risk factors for PMC among patients with hospital-acquired diarrhea (HAD). This study focused on identifying the clinical risk factors that can easily predict PMC. Methods The presumed HAD patients were prospectively recruited at the Hallym University Kangdong Sacred Heart Hospital. Results Age of 70 and older (adjusted odds ratio [OR], 1.76; 95% confidence interval [CI], 1.12 to 0.75), use of proton pump inhibitors (adjusted OR, 4.07; 95% CI, 2.512 to 6.57), use of cephalosporins (adjusted OR, 2.99; 95% CI, 1.82 to 4.94), and underlying cancer (adjusted OR, 1.72; 95% CI, 1.04 to 2.82) were independent risk factors for PMC in the multivariate logistic regression analysis. The prevalence of PMC was very low in the patients with HAD who exhibited no risk factors. Conclusions The risk factors for PMC in patients with HAD included cephalosporin use, proton pump inhibitor use, old age, and cancer. Considering the strongly negative predictive values of these risk factors, endoscopic evaluation can be delayed in patients with HAD without risk of developing PMC.