123 research outputs found

    Update of FRF matrix and physical parameters of finite element model

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    Numerically simulated results by finite element model of a dynamic system do rarely coincide with the actual responses of the structure due to the modeling, manufacturing errors or other causes. The parameters of the finite element model should be corrected for subsequent proper analysis. Minimizing a cost function by the difference between the analytical and actual dynamic stiffness matrices along with constrained conditions of measured FRFs (Frequency Response Functions), this work provides the mathematical form on the updated FRF. The updated parameter matrices of the structure are derived from the FRF variation within the prescribed frequency range. It is shown that the exactness of the proposed method depends on the number of the measured data. The validity of the proposed method is illustrated in updating the parameter matrices of a planar truss structure

    Damage detection of truss structure based on the variation in axial stress and strain energy predicted from incomplete measurements

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    This study derives the static equilibrium equation of a damaged system on the basis of stiffness change due to damage as well as the constraint forces at measurements required for obtaining the measured data. Based on the derived equations, this work provides an analytical method to detect damage from the stress and strain energy variations between intact and damaged truss structures. The applicability of the proposed method is evaluated in detecting multiple damages of low rate in the truss structure from measured data contaminated by external noise. It is demonstrated that it is possible to properly detect damage in an isolated substructure by partitioning the damage-expected substructure from an entire structure and using the displacements measured at the boundary of the partitioned subsystem. The partitioning method has the benefits in reducing the computational time and measured data as well as improving the effectiveness of the damage detection process

    Damage detection of truss structure based on the variation in axial stress and strain energy predicted from incomplete measurements

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    This study derives the static equilibrium equation of a damaged system on the basis of stiffness change due to damage as well as the constraint forces at measurements required for obtaining the measured data. Based on the derived equations, this work provides an analytical method to detect damage from the stress and strain energy variations between intact and damaged truss structures. The applicability of the proposed method is evaluated in detecting multiple damages of low rate in the truss structure from measured data contaminated by external noise. It is demonstrated that it is possible to properly detect damage in an isolated substructure by partitioning the damage-expected substructure from an entire structure and using the displacements measured at the boundary of the partitioned subsystem. The partitioning method has the benefits in reducing the computational time and measured data as well as improving the effectiveness of the damage detection process

    Assessment of the Prognostic Factors for a Local Recurrence of Rectal Cancer: the Utility of Preoperative MR Imaging

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    OBJECTIVE: To determine the utility of MR imaging in evaluating the prognostic factors for a local recurrence of rectal cancer following a curative resection. MATERIALS AND METHODS: The preoperative MR images obtained from 17 patients with a local recurrence and 54 patients without a local recurrence, who had undergone a curative resection, were independently evaluated by three radiologists. The following findings were analyzed: the direct invasion of the perirectal fat by the primary rectal carcinoma, involvement of the perirectal lymph nodes, perirectal spiculate nodules, perivascular encasement, and an enlargement of the pelvic wall lymph nodes. The clinical and surgical profiles were obtained from the patients' medical records. The association of a local recurrence with the MR findings and the clinicosurgical variables was statistically evaluated. RESULTS: Of the MR findings, the presence of perivascular encasement (p = 0.001) and perirectal spiculate nodules (p = 0.001) were found to be significant prognostic factors for a local recurrence. Of the clinicosurgical profiles, the presence of a microscopic vascular invasion (p = 0.005) and the involvement of the regional lymph nodes (p = 0.006) were associated with a local recurrence. Logistic regression analysis showed that the presence of perirectal spiculate nodules was an independent predictor of a local recurrence (odds ratio, 7.382; 95% confidence interval, 1.438, 37.889; p = 0.017). CONCLUSION: The presence of perirectal spiculate nodules and perivascular encasement on the preoperative MR images are significant predictors of a local recurrence after curative surgery for a rectal carcinoma. This suggests that preoperative MR imaging can provide useful information to help in the planning of preoperative adjuvant therapy.ope

    Ten-Year Trends of Utilizing Palliative Care and Palliative Procedures in Patients With Gastric Cancer in the United States From 2009 to 2018 - A Nationwide Database Study

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    Objectives: Little is known about the current status and the changing trends of hospitalization and palliative care consultation of patients with gastric cancer in the United States. The aim of this study was to evaluate the changing trend in the number of hospitalization, palliative care consultation, and palliative procedures in the US during a recent 10-year period using a nationwide database. Methods: This was a retrospective study that analyzed the National Inpatient Sample (NIS) database of 2009–2018. Patients aged more than 18 years who were diagnosed with a gastric cancer using International Classification of Diseases (ICD)-9 and 10 codes were included. Palliative care consultation included palliative care (ICD-9, V66.7; ICD-10, Z51.5) and advanced care planning (ICD-9, V69.89; ICD-10, Z71.89). Palliative procedures included percutaneous or endoscopic bypass, gastrostomy or enterostomy, dilation, drainage, nutrition, and irrigation for palliative purpose. Results and discussion: A total of 86,430 patients were selected and analyzed in this study. Using a compound annual growth rate (CAGR) approach, the annual number of hospitalizations of gastric cancer patients was found to be decreased during 2009–2018 (CAGR: -0.8%, P = 0.0084), while utilization rates of palliative care and palliative procedures increased (CAGR: 9.3 and 1.6%, respectively; P \u3c 0.0001). Multivariable regression analysis revealed that palliative care consultation was associated with reduced total hospital charges (−$34,188, P \u3c 0.0001). Conclusion: Utilization of palliative care consultation to patients with gastric cancer may reduce use of medical resources and hospital costs

    Dissociation Between the Growing Opioid Demands and Drug Policy Directions Among the U.S. Older Adults with Degenerative Joint Diseases

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    We aim to examine temporal trends of orthopedic operations and opioid-related hospital stays among seniors in the nation and states of Oregon and Washington where marijuana legalization was accepted earlier than any others. As aging society advances in the United States (U.S.), orthopedic operations and opioid-related hospital stays among seniors increase in the nation. A serial cross-sectional cohort study using the healthcare cost and utilization project fast stats from 2006 through 2015 measured annual rate per 100,000 populations of orthopedic operations by age groups (45–64 vs 65 and older) as well as annual rate per 100,000 populations of opioid-related hospital stays among 65 and older in the nation, Oregon and Washington states from 2008 through 2017. Orthopedic operations (knee arthroplasty, total or partial hip replacement, spinal fusion or laminectomy) and opioid-related hospital stays were measured. The compound annual growth rate (CAGR) was used to quantify temporal trends of orthopedic operations by age groups as well as opioid-related hospital stays and was tested by Rao–Scott correction of χ2 for categorical variables. The CAGR (4.06%) of orthopedic operations among age 65 and older increased (P...) (See full abstract in article

    Delivery of Factor VIII Gene into Skeletal Muscle Cells Using Lentiviral Vector

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    Purpose: This study was designed to investigate whether transduction of lentiviral vectors (LV) carrying human coagulation factor VIII (hFVIII) cDNA into skeletal muscle could increase circulating hFVIII concentrations. Materials and Methods: A LV containing bacterial LacZ gene as a control or human FVIII gene was intramuscularly administered into the thigh muscle of 5 weeks old Sparague-Dawley rats. The plasma human FVIII concentration and neutralizing anti-FVIII antibodies were measured for up to 12 weeks in these experimental animals. Results: The plasma human FVIII levels in the rats injected with LV carrying FVIII cDNA peaked at post-injection 1st week (5.19 ± 0.14 ng/mL vs. 0.21 ± 0.05 ng/mL in control rats, p < 0.05). Elevated hFVIII concentrations were maintained for 4 weeks (2.52 ± 0.83 ng/mL vs. 0.17 ± 0.08 ng/mL in control rats, p < 0.05) after a single intramuscular injection. In the Bethesda assay, neutralizing antibodies for FVIII protein were detected only in FVIII-LV injected rats by the 10th week, but not in control rats. Conclusion: This study suggested that a single administration of an advanced generation LV carrying the human FVIII cDNA resulted in elevation of FVIII level in immune competent rats, and that this gene transfer approach to the skeletal muscle could be an effective tool in treatment of hemophilia A. Key Words: Gene therapy, human coagulation factor VIII, hemophilia A, lentiviral vecto

    Comparison of CT and 18F-FDG PET for Detecting Peritoneal Metastasis on the Preoperative Evaluation for Gastric Carcinoma

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    OBJECTIVE: The aim of our study was to compare the accuracy of CT and (18)FFDG PET for detecting peritoneal metastasis in patients with gastric carcinoma. MATERIALS AND METHODS: One-hundred-twelve patients who underwent a histologic confirmative exam or treatment (laparotomy, n = 107; diagnostic laparoscopy, n = 4; peritoneal washing cytology, n = 1) were retrospectively enrolled. All the patients underwent CT and (18)F-FDG PET scanning for their preoperative evaluation. The sensitivities, specificities and accuracies of CT and (18)FFDG PET imaging for the detection of peritoneal metastasis were calculated and then compared using Fisher's exact probability test (p < 0.05), on the basis of the original preoperative reports. In addition, two board-certified radiologists and two board-certified nuclear medicine physicians independently reviewed the CT and PET scans, respectively. A receiver-operating characteristic curve analysis was performed to compare the diagnostic performance of CT and (18)F-FDG PET imaging for detecting peritoneal metastasis. RESULTS: Based on the original preoperative reports, CT and (18)F-FDG PET showed sensitivities of 76.5% and 35.3% (p = 0.037), specificities of 91.6% and 98.9% (p = 0.035), respectively, and equal accuracies of 89.3% (p = 1.0). The receptor operating characteristics curve analysis showed a significantly higher diagnostic performance for CT (Az = 0.878) than for PET (Az = 0.686) (p = 0.004). The interobserver agreement for detecting peritoneal metastasis was good (kappa value = 0.684) for CT and moderate (kappa value = 0.460) for PET. CONCLUSION: For the detection of peritoneal metastasis, CT was more sensitive and showed a higher diagnostic performance than PET, although CT had a relatively lower specificity than did PET.ope

    Regional Variation in States’ Naloxone Accessibility Laws in Association With Opioid Overdose Death Rates-Observational Study (STROBE Compliant)

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    Though overall death from opioid overdose are increasing in the United States, the death rate in some states and population groups is stabilizing or even decreasing. Several states have enacted a Naloxone Accessibility Laws to increase naloxone availability as an opioid antidote. The extent to which these laws permit layperson distribution and possession varies. The aim of this study is to investigate differences in provisions of Naloxone Accessibility Laws by states mainly in the Northeast and West regions, and the impact of naloxone availability on the rates of drug overdose deaths. This cross-sectional study was based on the National Vital Statistics System multiple cause-of-death mortality files. The average changes in drug overdose death rates between 2013 and 2017 in relevant states of the Northeast and West regions were compared according to availability of naloxone to laypersons. Seven states in the Northeast region and 10 states in the Western region allowed layperson distribution of naloxone. Layperson possession of naloxone was allowed in 3 states each in the Northeast and the Western regions. The average drug overdose death rates increased in many states in the both regions regardless of legalization of layperson naloxone distribution. The average death rates of 3 states that legalized layperson possession in the West region decreased (-0.33 per 100,000 person); however, in states in the West region that did not allow layperson possession and states in the Northeast region regardless of layperson possession increased between 2013 and 2017. The provision to legalize layperson possession of naloxone was associated with decreased average opioid overdose death rates in 3 states of the West region
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