Identification of joint parameters using FRF based decoupling

Structural and mechanical systems are assembled from smaller components using mechanical joints. The mechanical properties of the joints must be modeled in order to perform subsequent design and analysis of the structure or mechanical system. This study provides an analytical method of determining the parameters that describe the behavior of the joints using frequency response function (FRF) data that is measured at joint nodes. The variation in FRFs is derived by utilizing the consistent response conditions at the same joint nodes of the assembly system and the portioned subsystems. The variation reflects the mechanical properties of the joint and is utilized to extract the joint parameters. The validity of the proposed method is illustrated in two numerical applications

Candida Arthritis after Arthroscopic Arthroplasty in a Patient without Predisposing Factors

Because candidiasis is usually associated with immunosuppression, candida arthritis in an immunocompetent patient is rare. The symptoms of candidiasis are similar to bacterial infections, tuberculosis, and autoimmune diseases. In our patient with no predisposing factors, candida arthritis was initially excluded because the probability of occurrence was low. The patient had no leukocytosis, the acid-fast bacteria (AFB) stain was negative, and the autoimmune antibody screen was negative. After Candida parapsilosis was cultured in the synovial fluid, the patient was treated with amphotericin B (0.7 mg/kg/day) and oral fluconazole (400 mg/day). The treatment was successful and there were no side effects of the medications

Airborne Measurements of High Pollutant Concentration Events in the Free Troposphere over the West Coast of South Korea between 1997 and 2011

Aircrafts enable the direct measurement of chemical components in the free troposphere (FT). This study employed airborne measurements to examine the occurrences of high concentrations of SO2 and NOx in the FT over the coastal region west of the Seoul metropolitan area, South Korea. The data from a long-term (1997-2011) airborne measurement campaign were used to determine the meteorological conditions favorable for carrying these pollutants into the Seoul area. The back trajectory analyses of 21 instances of high FT pollutant concentration events showed ascending patterns from the major pollutant sources, mainly the industrial complexes in eastern China, in 9 instances and passing patterns in 12 instances. In the ascending instances, developing low-pressure systems over the source regions provide favorable conditions to uplift air pollutants from the surface into the FT. In the passing instances, an anomalous low-pressure system near the surface prevented airflows from descending into the boundary layer and upper-level anticyclonic systems helped to keep the ascending airflows in the FT. This study proposes the basic mechanisms for predicting air quality in the Seoul area, considering that air pollutants in the FT often entrain into the boundary layer to increase local concentrationsopen0

Microporation is a valuable transfection method for efficient gene delivery into human umbilical cord blood-derived mesenchymal stem cells

<p>Abstract</p> <p>Background</p> <p>Mesenchymal stem cells (MSCs) are an attractive source of adult stem cells for therapeutic application in clinical study. Genetic modification of MSCs with beneficial genes makes them more effective for therapeutic use. However, it is difficult to transduce genes into MSCs by common transfection methods, especially nonviral methods. In this study, we applied microporation technology as a novel electroporation technique to introduce enhanced green fluorescent protein (EGFP) and brain-derived neurotropfic factor (BDNF) plasmid DNA into human umbilical cord blood-derived MSCs (hUCB-MSCs) with significant efficiency, and investigated the stem cell potentiality of engineered MSCs through their phenotypes, proliferative capacity, ability to differentiate into multiple lineages, and migration ability towards malignant glioma cells.</p> <p>Results</p> <p>Using microporation with EGFP as a reporter gene, hUCB-MSCs were transfected with higher efficiency (83%) and only minimal cell damage than when conventional liposome-based reagent (<20%) or established electroporation methods were used (30-40%). More importantly, microporation did not affect the immunophenotype of hUCB-MSCs, their proliferation activity, ability to differentiate into mesodermal and ectodermal lineages, or migration ability towards cancer cells. In addition, the BDNF gene could be successfully transfected into hUCB-MSCs, and BDNF expression remained fairly constant for the first 2 weeks <it>in vitro </it>and <it>in vivo</it>. Moreover, microporation of BDNF gene into hUCB-MSCs promoted their <it>in vitro </it>differentiation into neural cells.</p> <p>Conclusion</p> <p>Taken together, the present data demonstrates the value of microporation as an efficient means of transfection of MSCs without changing their multiple properties. Gene delivery by microporation may enhance the feasibility of transgenic stem cell therapy.</p