Modeling of composite beams and plates for static and dynamic analysis

A rigorous theory and corresponding computational algorithms was developed for a variety of problems regarding the analysis of composite beams and plates. The modeling approach is intended to be applicable to both static and dynamic analysis of generally anisotropic, nonhomogeneous beams and plates. Development of a theory for analysis of the local deformation of plates was the major focus. Some work was performed on global deformation of beams. Because of the strong parallel between beams and plates, the two were treated together as thin bodies, especially in cases where it will clarify the meaning of certain terminology and the motivation behind certain mathematical operations

Modeling of composite beams and plates for static and dynamic analysis

The main purpose of this research was to develop a rigorous theory and corresponding computational algorithms for through-the-thickness analysis of composite plates. This type of analysis is needed in order to find the elastic stiffness constants for a plate and to post-process the resulting plate solution in order to find approximate three-dimensional displacement, strain, and stress distributions throughout the plate. This also requires the development of finite deformation plate equations which are compatible with the through-the-thickness analyses. After about one year's work, we settled on the variational-asymptotical method (VAM) as a suitable framework in which to solve these types of problems. VAM was applied to laminated plates with constant thickness in the work of Atilgan and Hodges. The corresponding geometrically nonlinear global deformation analysis of plates was developed by Hodges, Atilgan, and Danielson. A different application of VAM, along with numerical results, was obtained by Hodges, Lee, and Atilgan. An expanded version of this last paper was submitted for publication in the AIAA Journal

Value of Paraspinal Electromyography in the Evaluation of Thoracic Myelopathy

The authors have performed paraspinal needle EMG studies in twenty five patients with thoracic myelopathy. They were divided into demonstrable thoracic lesions and non-demonstrable thoracic lesions by neuroimaging studies resulting in 12 cases of the former and 13 cases of the latter. There were abnormal paraspinal EMG findings in 83% with demonstrable thoracic lesions. All five patients with thoracic disc diseases revealed abnormalities which indicated subsequent involvement of ventral roots by compressive lesions. In non-demonstrable thoracic lesions, the authors could demonstrate abnormal paraspinal EMGs in a relatively high percentage (62.5%) of preseumed and still occult thoracc myelopathy, but not in all four patients with demyelinating disease. Therefore it is concluded that paraspinal EMG studies are valuable in those patients wih thoracic myelopathy as a method of predicting he presumed nature of their causes and indicating the level of anticipated myelography or spinal CT. However, it was impossible to differentiate among patients with malignancy, those with thoracic disc diseases and those with unknown thoracic myelopathy by the paraspinal EMG studies

Cloning, expression, purification, crystallization and X-ray crystallographic analysis of glucuronic acid dehy­drogenase from Chromohalobacter salexigens. Addendum

An addendum to the article by Ahn et al. [Acta Cryst. (2011) F67, 689–691]

Visual prognosis and surgical timing of Ahmed glaucoma valve implantation for neovascular glaucoma secondary to diabetic vitrectomy

Evaluate the visual outcomes of Ahmed glaucoma valve implantation (AGVI) in patients with neovascular glaucoma (NVG) who underwent diabetic vitrectomy and suggest appropriate AGVI timing. Methods Medical records of patients who underwent AGVI due to NVG after diabetic vitrectomy were reviewed. Successful intraocular pressure (IOP) control was defined as an IOP between 6 and 21 mmHg. Visual outcome was compared before NVG diagnosis and after AGVI, and the favorable visual outcome was defined as a postoperative deterioration in BCVA of less than 0.3 logMAR units compared to those before the development of NVG. Various factors including surgical timing were evaluated to identify the risk factors associated with unfavorable visual outcome. Results A total of 35 eyes were enrolled and divided into group 1(medically uncontrolled NVG group, IOP more than 30mmHg, 16 eyes) and group 2(NVG group responded well to the initial non-surgical treatment but eventually required AGVI, 19 eyes). Despite the favorable rate of normalization of post-AGVI IOP (85.7%), 43.8% in Group 1 and 26.3% in Group 2 showed unfavorable visual outcomes. In group 1, delayed surgical timing more than 1 week from the NVG diagnosis showed a significant association with unfavorable visual outcomes (P = 0.041). In group 2, poor patient compliance (follow up loss, refuse surgery) was the main factor of unfavorable visual outcomes. Conclusion When NVG occurs in patients with proliferative diabetic retinopathy after vitrectomy, physicians should be cautious not to delay the surgical intervention, especially in patients with IOP of 30 or more despite non-surgical treatment. Early AGVI within six days might be necessary to preserve useful vision in these patients

Clinical characteristics of 2009 pandemic influenza A (H1N1) infection in children and the performance of rapid antigen test

PurposeIn autumn 2009, the swine-origin influenza A (H1N1) virus spread throughout South Korea. The aims of this study were to determine the clinical characteristics of children infected by the 2009 H1N1 influenza A virus, and to compare the rapid antigen and real-time polymerase chain reaction (PCR) tests.MethodsWe conducted a retrospective review of patients ≥18 years of age who presented to Soonchunhyang University Hospital in Seoul with respiratory symptoms, including fever, between September 2009 and January 2010. A real-time PCR test was used to definitively diagnose 2009 H1N1 influenza A infection. Medical records of confirmed cases were reviewed for sex, age, and the time of infection. The decision to perform rapid antigen testing was not influenced by clinical conditions, but by individual factors such as economic conditions. Its sensitivity and specificity were evaluated compared to real-time PCR test results.ResultsIn total, 934 patients tested positive for H1N1 by real-time PCR. The highest number of patients (48.9%) was diagnosed in November. Most patients (48.2%) were aged between 6 and 10 years. Compared with the H1N1 real-time PCR test results, the rapid antigen test showed 22% sensitivity and 83% specificity. Seventy-eight patients were hospitalized for H1N1 influenza A virus infection, and fever was the most common symptom (97.4%).ConclusionFor diagnosis of 2009 H1N1 influenza A virus infection, the rapid antigen test was inferior to the real-time PCR test in both sensitivity and specificity. This outcome suggests that the rapid antigen test is inappropriate for screening