Damage detection and identification of parameter matrices using residual force vector

Beginning with incomplete mode shape measurement data, this study presents analytical equations to predict the actual stiffness and mass matrices. The measured modal data, including the measurement, manufacturing and modeling errors, should be updated for subsequent analysis. In this study, the incomplete mode shape data are expanded to a full set of degrees-of-freedom (DOFs) based on the generalized inverse method and the concept of residual force vector. The corrected parameter matrices are straightforwardly derived using the estimated mode shape data and the pseudo inverse method. The validity of the proposed method is evaluated based on the number of measured modes in an application, and its limitations are investigated

Damage detection and identification of parameter matrices using residual force vector

Beginning with incomplete mode shape measurement data, this study presents analytical equations to predict the actual stiffness and mass matrices. The measured modal data, including the measurement, manufacturing and modeling errors, should be updated for subsequent analysis. In this study, the incomplete mode shape data are expanded to a full set of degrees-of-freedom (DOFs) based on the generalized inverse method and the concept of residual force vector. The corrected parameter matrices are straightforwardly derived using the estimated mode shape data and the pseudo inverse method. The validity of the proposed method is evaluated based on the number of measured modes in an application, and its limitations are investigated

The value of chest CT for prediction of breast tumor size: comparison with pathology measurement

BACKGROUND: Little information is available on the use of chest computed tomography (CT) to predict breast tumor size in breast cancer, despite the fact that chest CT examinations are being increasingly used. The purpose of this study was to evaluate the value of chest CT for predicting breast tumor size using pathology measurements as reference standards. METHODS: Tumor sizes (defined as greatest diameter) were retrospectively measured on the preoperative chest CT images of 285 patients with surgically proven unifocal, invasive breast carcinoma. Greatest tumor diameters as determined by chest CT and pathologic examinations were compared by linear regression and Spearman’s rho correlation analysis. Concordance between CT and pathology results was defined as a diameter difference of <5 mm. Subgroup analyses were also performed with respect to tumor size (<20 mm or ≥20 mm) and histological subtype (invasive ductal carcinoma(IDC) or non-IDC). RESULTS: CT and pathology measured diameters were found to be linearly related (size at pathology = 1.086 × CT determined tumor size - 1.141; Spearman’s rho correlation coefficient = 0.84, P<0.001). Most tumors (n = 228, 80.0%) were concordant by chest CT and pathology, but 36 tumors (12.7%) were underestimated by CT (average underestimation, 11 mm; range, 6–36 mm) and 21 tumors (7.4%) were overestimated (average overestimation by CT, 10 mm; range, 6–19 mm). The concordance rate between the two sets of measurements was greater for tumor of <20 mm and for IDC (P<0.001 and P = 0.011, respectively). CONCLUSIONS: Tumor size by chest CT is well correlated with pathology determined tumor size in breast cancer patients, and the diameters of the majority of tumors by chest CT and pathology differed by <5 mm. In addition, the concordance rate was higher for breast tumors of <20 mm and for tumors of the IDC histologic subtype

Incidence and Risk Factors Associated with Superior Mesenteric Artery Syndrome following Surgical Correction of Scoliosis

STUDY DESIGN: Retrospective study. PURPOSE: To more accurately determine the incidence and clarify risk factors. OVERVIEW OF LITERATURE: Superior mesenteric artery syndrome is one of the possible complications following correctional operation for scoliosis. However, when preliminary symptoms are vague, the diagnosis of superior mesenteric artery syndrome may be easily missed. METHODS: We conducted a retrospective study using clinical data from 118 patients (43 men and 75 women) who underwent correctional operations for scoliosis between September 2001 and August 2007. The mean patient age was 15.9 years (range 9~24 years). The risk factors under scrutiny were the patient body mass index (BMI), change in Cobb's angle, and trunk length. RESULTS: The incidence of subjects confirmed to have obstruction was 2.5%. However, the rate increased to 7.6% with the inclusion of the 6 subjects who only showed clinical symptoms of obstruction without confirmative study. The BMI for the asymptomatic and symptomatic groups were 18.4+/-3.4 and 14.6+/-3, respectively. The change in Cobb's angle for the asymptomatic and symptomatic groups were 24.8+/-13.6 degrees and 23.4+/-9.1 degrees , respectively. The change in trunk length for the asymptomatic and symptomatic groups were 2.3+/-2.1 cm and 4.5+/-4.8 cm, respectively. Differences in Cobb's angle and the change in trunk length between the two groups did not reach statistical significance, although there was a greater increase in trunk length for the symptomatic group than for the asymptomatic group. CONCLUSIONS: Our study shows that the incidence of superior mesenteric artery syndrome may be greater than the previously accepted rate of 4.7%. Therefore, in the face of any early signs or symptoms of superior mesenteric artery syndrome, prompt recognition and treatment are necessaryope

Association of epicardial fat with left ventricular diastolic function in subjects with metabolic syndrome: assessment using 2-dimensional echocardiography

Background Metabolic syndrome (MetS) is related with left ventricular diastolic dysfunction (LVDD) and poor cardiovascular outcome. Epicardial adipose tissue (EAT) thickness, measured by echocardiography, is increased in subjects with MetS. However, the association of EAT with LV diastolic function has not been evaluated in subjects with MetS. Methods In this retrospective study, EAT thickness was measured in 1,486 consecutive asymptomatic patients with no known heart disease who had transthoracic echocardiography during a self-referred healthcare exam. Subjects with a history of ischemic heart disease, cardiomyopathy or significant valvular heart disease were excluded. LVDD was defined as E/e ratio ≥ 15. Subjects were grouped into two groups, those with MetS and those without. Results MetS was present in 346 subjects. There was no difference in LV systolic function between the two groups. However compared to patients without MetS, patients with MetS had larger left atrium (LA) size and higher E/e ratio (38 ± 5 versus 35 ± 5 mm for LA and 10.0 ± 3.3 versus 8.7 ± 2.7 for E/e ratio in subjects with versus without MetS both p < 0.001). LVDD was found in 27 (7.8%) subjects with MetS, compared to 30 (2.6%) subjects without MetS (p < 0.001). In subjects with MetS, EAT was significantly correlated with LVDD, even after adjusting for other cardiometabolic risk factors such as age, systolic blood pressure, BMI, blood glucose and LDL cholesterol (OR 1.845, 95% CI 1.153-2.951, p = 0.011).This study was supported by Seoul National University Hospital (0420100700, 2010–1096).Peer Reviewe

Measurement of the Background Activities of a 100Mo-enriched powder sample for AMoRE crystal material using a single high purity germanium detector

The Advanced Molybdenum-based Rare process Experiment (AMoRE) searches for neutrino-less double-beta (0{\nu}\b{eta}\b{eta}) decay of 100Mo in enriched molybdate crystals. The AMoRE crystals must have low levels of radioactive contamination to achieve low background signals with energies near the Q-value of the 100Mo 0{\nu}\b{eta}\b{eta} decay. To produce low-activity crystals, radioactive contaminants in the raw materials used to form the crystals must be controlled and quantified. 100EnrMoO3 powder, which is enriched in the 100Mo isotope, is of particular interest as it is the source of 100Mo in the crystals. A high-purity germanium detector having 100% relative efficiency, named CC1, is being operated in the Yangyang underground laboratory. Using CC1, we collected a gamma spectrum from a 1.6-kg 100EnrMoO3 powder sample enriched to 96.4% in 100Mo. Activities were analyzed for the isotopes 228Ac, 228Th, 226Ra, and 40K. They are long-lived naturally occurring isotopes that can produce background signals in the region of interest for AMoRE. Activities of both 228Ac and 228Th were < 1.0 mBq/kg at 90% confidence level (C.L.). The activity of 226Ra was measured to be 5.1 \pm 0.4 (stat) \pm 2.2 (syst) mBq/kg. The 40K activity was found as < 16.4 mBq/kg at 90% C.L.Comment: 20 pages, 6 figures, 5 table

Fabrication of agar-based tissue-mimicking phantom for the technical evaluation of biomedical optical imaging systems

The development process of the optical systems for various biomedical applications typically involve evaluations of technical performance. One popular evaluation method is to use a reference object such as a phantom that exhibits similar optical properties of tissue. Fabrication of a consistent phantom with known optical properties, such as scattering and absorption, is essential for accurate technical evaluation of the optical system. This paper presents a protocol for fabricating an agar-based tissue-mimicking phantom, offering practical guidance to ensure consistent and reproducible phantom creation. In addition, optical setups that measure light information required for quantifying the optical properties via an inverse adding-doubling (IAD) method are discussed. We demonstrated the fabrication of phantoms with diverse scattering and absorption properties, and the IAD method successfully quantified the optical properties. Moreover, we employed the phantom to assess the imaging depth limitation of a hyperspectral imaging system, demonstrating potential usage of phantoms for performing technical evaluation.</p