Simultaneous detection of the nonlinear restoring and excitation of a forced nonlinear oscillation: an integral approach

We address in this article, how to calculate the restoring characteristic and the excitation of a nonlinear forced oscillating system. Under the assumption that the forced nonlinear oscillator has a periodic solution with period, we constructed a system of linear equations by introducing time-dependent multipliers. The periodicity assumption helps simplify the system of linear equations. The stability and uniqueness are also presented for the inverse problem. Numerical testing is conducted to show the effectiveness of our presented methodology.Peer ReviewedPostprint (author's final draft

Design and Experimental Validation of a Control System for Dynamic Positioning of a Shuttle Tanker

In this paper, a dynamic positioning performance evaluation procedure for a shuttle tanker is discussed through experimental and numerical analyses. A dynamically positioned shuttle tanker with six thrusters (three tunnel thrusters, two azimuth thrusters, and one main propeller with a rudder), operated in deep water condition was considered. A conventional proportional-derivative control algorithm was adopted for the main feedback control algorithm to reduce the position error, and an anti-windup integral control algorithm was introduced to suppress the steady-state error in the dynamic positioning operation. A minimum power consumption algorithm, based on the Lagrange multiplier method, was utilised in the thrust allocation for the thruster systems. An extended Kalman filter was used in the experiment to separate the low-frequency motion from the measured vessel motion. A set of experiments and numerical analyses were conducted in this study under the same environmental conditions and with the same control methodology. The dynamic positioning operation results obtained by the experiments and numerical simulations were compared to evaluate the station-keeping performance of the dynamically positioned shuttle tanker

Draft genome sequence of a caprolactam degrader bacterium: Pseudomonas taiwanensis strain SJ9

AbstractPseudomonas taiwanensis strain SJ9 is a caprolactam degrader, isolated from industrial wastewater in South Korea and considered to have the potential for caprolactam bioremediation. The genome of this strain is approximately 6.2 Mb (G+C content, 61.75%) with 6,010 protein-coding sequences (CDS), of which 46% are assigned to recognized functional genes. This draft genome of strain SJ9 will provide insights into the genetic basis of its caprolactam-degradation ability

Prognostic Factors Influencing Infection-related Mortality in Patients with Acute Leukemia in Korea

We retrospectively reviewed the medical records of 284 patients with neutropenic fever following chemotherapy for acute leukemia at the Catholic Hematopoietic Stem Cell Transplantation Center from January 1998 to December 1999, to identify prognostic factors for infection related mortality. Twenty-eight patients died of infections. There was no difference in median age, gender ratio, or underlying disease between the dying and surviving groups. Bacteria were the main pathogens following chemotherapy, and Gram positive organisms predominated in the dying group. Pneumonia and sepsis were the main causes of death. There were 72 cases of invasive fungal infection and their mortality was 27.8%. Invasive fungal infection and previous history of fungal infection were independent prognostic factors for outcome. Recovery from neutropenia was the significant protective factor for mortality. In conclusion, the prognostic factors identified in this study could be useful for deciding on more intensive treatment for those patients at greater risk of death. To our knowledge, this is the first Korean study delineating prognostic factors in acute leukemic patients with infectious complications

Current Trends of Infectious Complications following Hematopoietic Stem Cell Transplantation in a Single Center

This study was to analyze the infectious complications after hematopoietic stem cell transplantation (HSCT) according to the recent changes of HSCT. Medical records of 379 adult patients who underwent HSCT consecutively at Catholic HSCT Center from January 2001 to December 2002 were reviewed retrospectively. Allogeneic HSCT accounted for 75.7% (287/379) and autologous HSCT for 24.3% (92/379). During pre-engraftment period, bacterial infection was predominant, and E. coli was still the most common organism. After engraftment, viral infection was predominant. The incidence of invasive fungal infection showed bimodal distribution with peak correlated with neutropenia and graft-versus-host disease (GVHD). The overall mortality and infection-related mortality rates according to 3 periods were as follows; during pre-engraftment, 3.16% (12/379) and 1.8% (7/379); during midrecovery period, 7.9% (29/367) and 4.1% (15/367); during late-recovery period, 26.9% (91/338), and 15.9% (54/338). Risk factors for infection-related mortality were as follows; during pre-engraftment period, fungal infection and septic shock; during the mid-recovery period, hemorrhagic cystitis and delayed engraftment; during the late-recovery period, fungal infection, chronic GVHD, and relapse. In conclusion, infection was still one of the main complications after HSCT and highly contributes to mortality. The early diagnosis and the effective vaccination strategy are needed for control of infections

Comparison of Quantitative Cytomegalovirus Real-time PCR in Whole Blood and pp65 Antigenemia Assay: Clinical Utility of CMV Real-time PCR in Hematopoietic Stem Cell Transplant Recipients

Successful preemptive therapy for cytomegalovirus (CMV) infection in transplant patients depends on the availability of sensitive, specific, and timely diagnostic tests for CMV infection. Although the pp65 antigenemia assay has been widely used for this purpose, real-time quantification of CMV DNA has recently been recognized as an alternative diagnostic approach. However, the guidelines for antiviral therapy based on real-time quantitative polymerase chain reaction (RQ-PCR) have yet to be established. From November 2004 to March 2005, a total of 555 whole blood samples from 131 hematopoietic stem cell transplant (HSCT) recipients were prospectively collected. RQ-PCR was conducted using an Artus® CMV LC PCR kit (QIAGEN). Both qualitative and quantitative correlations were drawn between the two methods. Exposure to the antiviral agent influenced the results of the two assays. Additionally, the discrepancy was observed at low levels of antigenemia and CMV DNA load. Via ROC curve analysis, the tentative cutoff value for preemptive therapy was determined to be approximately 2×104 copies/mL (sensitivity, 80.0%; specificity, 50.0%) in the high risk patients, and approximately 3×104 copies/mL (sensitivity, 90.0%; specificity, 70.0%) in the patients at low risk for CMV disease. Further study to validate the optimal cutoff value for the initiation of preemptive therapy is currently underway

Rapid access to polycyclic N-heteroarenes from unactivated, simple azines via a base-promoted Minisci-type annulation

Conventional synthetic methods to yield polycyclic heteroarenes have largely relied on metal-mediated arylation reactions requiring pre-functionalised substrates. However, the functionalisation of unactivated azines has been restricted because of their intrinsic low reactivity. Herein, we report a transition-metal-free, radical relay pi-extension approach to produce N-doped polycyclic aromatic compounds directly from simple azines and cyclic iodonium salts. Mechanistic and electron paramagnetic resonance studies provide evidence for the in situ generation of organic electron donors, while chemical trapping and electrochemical experiments implicate an iodanyl radical intermediate serving as a formal biaryl radical equivalent. This intermediate, formed by one-electron reduction of the cyclic iodonium salt, acts as the key intermediate driving the Minisci-type arylation reaction. The synthetic utility of this radical-based annulative pi-extension method is highlighted by the preparation of an N-doped heptacyclic nanographene fragment through fourfold C-H arylation. The functionalisation of unactivated azines has been restricted because of their intrinsic low reactivity. Here the authors show a transition-metal-free, radical relay pi-extension approach to produce N-doped polycyclic aromatic compounds directly from simple azines and cyclic iodonium salts

Clinical Characteristics and Outcomes of Posttransplant Lymphoproliferative Disorders Following Allogeneic Hematopoietic Stem Cell Transplantation in Korea

Between 1995 and 2003, seven cases of posttransplant lymphoproliferative disorder (PTLD) were identified among 1,116 patients who received allogeneic hematopoietic stem cell transplantations (HSCT) at Catholic HSCT Center (overall incidence 0.6%). Five (71.4%) patients had episodes of acute graft-versus-host-disease (GVHD) and were treated with steroids. Cervical lymphadenopathy was observed in most cases (71.4%), but clinical symptoms varied depending on the involved sites. Pathologic findings varied: 1 case of plasmacytic hyperplasia, 3 of polymorphic PTLD, 2 of diffuse large B-cell lymphoma, 1 of large T-cell lymphoma, which proved to be associated with Epstein-Barr virus (EBV). The proportion of EBV-negative PTLD was 33.3%. Five patients demonstrated a good response to treatment (treatment response rate 71.4%). The overall mortality was 42.8%, and one death was directly attributable to PTLD. The incidence of PTLD is expected to increase, based on the rising use of grafts from alternative donors and recent clinical features of PTLD manifested by a disseminated and fulminant nature. It is necessary to have a high level of suspicion when monitoring patients and readily adopt prompt and effective cellular immunotherapy for PTLD