630 research outputs found

    A Robust Controller Design Method for a Flexible Manipulator with a Large Time Varying Payload and Parameter Uncertainties

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    Abstract. A new robust controller design method is proposed to obtain a less conservative feedback controller and it is applied to a single-link flexible manipulator. The objective is to maximize the control performance guaranteeing the robust stability when regulating the tip position of the flexible manipulator in the presence of a large time-varying payload and parameter uncertainties such as stiffness and joint friction. A descriptor form representation, which allows separate treatment of payload uncertainty from other parametric uncertainties, is used to reduce the conservatism of the conventional robust control approaches. Uncertainty of the payload in the inertia matrix is represented by polytopic approach and the uncertain parameters in the damping and stiffness matrices are treated with descaling techniques. Using aforementioned techniques, the robust LQ controller design problem for a flexible manipulator based on the guaranteed cost approach is formulated. Then, the formulated problem is solved by LMIs

    Molecular characterization of tetracycline- and quinolone-resistant Aeromonas salmonicida isolated in Korea

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    The antibiotic resistance of 16 Aeromonas (A.) salmonicida strains isolated from diseased fish and environmental samples in Korea from 2006 to 2009 were investigated in this study. Tetracycline or quinolone resistance was observed in eight and 16 of the isolates, respectively, based on the measured minimal inhibitory concentrations. Among the tetracycline-resistant strains, seven of the isolates harbored tetA gene and one isolate harbored tetE gene. Additionally, quinolone-resistance determining regions (QRDRs) consisting of the gyrA and parC genes were amplified and sequenced. Among the quinolone-resistant A. salmonicida strains, 15 harbored point mutations in the gyrA codon 83 which were responsible for the corresponding amino acid substitutions of Ser83→Arg83 or Ser83→Asn83. We detected no point mutations in other QRDRs, such as gyrA codons 87 and 92, and parC codons 80 and 84. Genetic similarity was assessed via pulsed-field gel electrophoresis, and the results indicated high clonality among the Korean antibiotic-resistant strains of A. salmonicida

    Relationships between 24-Hour Blood Pressures, Subcortical Ischemic Lesions, and Cognitive Impairment

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    Background and Purpose The most important treatment for subcortical vascular dementia (SVaD) is controlling the blood pressure (BP). However, the few studies that have investigated the relationships between diurnal BP rhythm and subcortical ischemic vascular cognitive impairment have produced inconclusive results. In the study presented here, the 24-hour BP values of three groups of subjects-patients with subcortical vascular mild cognitive impairment (SvMCI), patients with SVaD, and normal controls-were compared using working criteria and 24-hour ambulatory BP (ABP) monitoring. Methods The subjects (42 patients with SVaD, 37 patients with SvMCI, and 30 controls) were selected according to the Study`s inclusion/exclusion criteria. All subjects underwent brain magnetic resonance (MR) imaging and MR angiography, detailed neuropsychological testing, and 24-hour ABP monitoring. Results The prevalence of nondippers differed markedly between the control group and both the SVaD and SvMCI groups. Loss of nocturnal dipping was significantly associated with SVaD [odds ratio (OR), 4.827; 95% confidence interval (CI), 1.07-12.05]. Conclusions It was found that SVaD is associated with loss of nocturnal BP dipping combined with increased pulse pressure and systolic BP (SBP) variability. Correction of these factors could therefore be important in the prevention of SVaD, independent of measures used to reduce BP. J Clin Neurol 2009;5:139-145Ohmine T, 2008, HYPERTENS RES, V31, P75van Boxtel MPJ, 2006, J HUM HYPERTENS, V20, P5, DOI 10.1038/sj.jhh.1001934van der Flier WM, 2005, STROKE, V36, P2116Birns J, 2005, STROKE, V36, P1308, DOI 10.1161/01.STR.0000165901.38039.5fYamamoto Y, 2005, CEREBROVASC DIS, V19, P302, DOI 10.1159/000084498BOWLER JV, 2005, J NEUROL NEUROSUR S5, V76, P35KU HM, 2004, J KOREAN NEUROPSYCHI, V43, P189O`Brien E, 2003, J HYPERTENS, V21, P821, DOI 10.1097/01.hjh.0000059016.82022.caKANG Y, 2003, INCHEON HUMAN BRAINOhkubo T, 2002, J HYPERTENS, V20, P2183de Leeuw FE, 2002, BRAIN, V125, P765O`Brien JT, 2002, ANN NY ACAD SCI, V977, P436Kario K, 2001, HYPERTENSION, V38, P852Wahlund LO, 2001, STROKE, V32, P1318Dufouil C, 2001, NEUROLOGY, V56, P921Puisieux F, 2001, EUR NEUROL, V46, P115Staessen JA, 1999, JAMA-J AM MED ASSOC, V282, P539Swan GE, 1998, NEUROLOGY, V51, P986Blacher J, 1998, HYPERTENSION, V32, P570Cummings JL, 1998, J PSYCHOSOM RES, V44, P627Kilander L, 1998, HYPERTENSION, V31, P780Guo ZC, 1997, AM J EPIDEMIOL, V145, P1106Liao DP, 1996, STROKE, V27, P2262LAUNER LJ, 1995, JAMA-J AM MED ASSOC, V274, P1846YAMAMOTO Y, 1995, STROKE, V26, P829VERDECCHIA P, 1994, HYPERTENSION, V24, P793KUUSISTO J, 1993, HYPERTENSION, V22, P771SHIMADA K, 1992, J HYPERTENS, V10, P875SCHERR PA, 1991, AM J EPIDEMIOL, V134, P1303TOHGI H, 1991, STROKE, V22, P603OBRIEN E, 1988, LANCET, V2, P397PARATI G, 1987, J HYPERTENS, V5, P93HACHINSKI VC, 1975, ARCH NEUROL-CHICAGO, V32, P632

    Radical prostatectomy versus radiotherapy as local therapy for primary tumors in patients with oligometastatic prostate cancer

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    IntroductionWe compared radical prostatectomy (RP) and radiotherapy (RT) as local therapies for primary tumors and examined their associations with survival outcomes and urinary tract complications in patients with oligometastatic prostate cancer (omPC).MethodsWe evaluated the data of 85 patients diagnosed with omPC who underwent local therapy for primary tumors between January 2008 and December 2018. Of the 85 patients, 31 underwent prostate RT, while 54 underwent RP. Oligometastatic disease was defined as the presence of fewer than five metastatic lesions without visceral metastasis. Urinary tract complications, progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS) were evaluated using the Kaplan–Meier method and Cox regression analyses. ResultsPatients treated with RT showed higher prostate-specific antigen levels. There was no significant difference in the 5-year PFS (52.5% vs. 37.9%, p=0.351), CSS (67.6% vs. 84.7%, p=0.473), or OS (63.6% vs. 73.8%, p=0.897) between the RT and RP groups. In the multivariate analyses, the type of local therapy was not associated with PFS (hazard ratio [HR]=1.334, p=0.356), CSS (HR=0.744, p=0.475), or OS (HR=0.953, p=0.897). ConclusionTherefore, RP seems to be a possible treatment option for patients with omPC, exhibiting oncologic outcomes comparable to those with RT

    The impact of non-pharmaceutical interventions on premature births during the COVID-19 pandemic: a nationwide observational study in Korea

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    BackgroundNon-pharmaceutical interventions (NPIs), such as social distancing and hand washing, have been associated with a decline in the preterm birth rate worldwide. We aimed to evaluate whether the preterm birth rate in Korea during the coronavirus disease 2019 lockdown has changed compared to that in previous years.MethodA birth registry from the Korea Statistical Information Service, which is a nationwide official database, was used to include all births claimed to have occurred between 2011 and 2020. Newborns with gestational age (GA) less than 22 weeks and birth weight less than 220 g were excluded. The pre-NPI period was designated as January 2011 to January 2020, and the NPI period was defined as February 2020 to December 2020. We assessed the effect of NPI on the incidence of prematurity per 100 births using an interrupted time-series quasi-experimental design and implementing an autoregressive integrated moving average (ARIMA) model.ResultsFrom 2011 to 2020, a total of 3,931,974 live births were registered, among which 11,416 were excluded. Consequently, the final study population included 3,920,558 live births (both singleton and multiple births) among which 275,009 (7.0%) were preterm. The preterm birth rate was significantly higher during the NPI period (8.68%) compared to that in the pre-NPI period (6.92%) (P < 0.001). The ARIMA model showed that in all singleton and multiple births, except those in July (observed 9.24, expected 8.54, [95% prediction interval {PI} 8.13–8.96], percent difference 7.81%), September (observed 7.89, expected 8.35, [95% PI 7.93–8.76], percent difference −5.66%), and December (observed 9.90, expected 9.40, [95% PI 8.98–9.82], percent difference 5.2%), most observed values were within the 95% PI of the expected values and showed an increasing trend.ConclusionIn this nationwide observational study, the trend in premature birth rate did not significantly change due to NPI implementation in Korea, as it had been increasing since 2011. The trend of Korea's birth rate appears to be unaffected by the implementation of NPIs; however, further studies with a longer follow-up period are needed

    Neonatal Bladder Irritation Is Associated With Vanilloid Receptor TRPV1 Expression in Adult Rats

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    Purpose To evaluate whether mild chemical irritation of the bladder in neonatal rats is associated with persistent vanilloid receptor transient receptor potential vanilloid subfamily 1 (TRPV1) activity in adult rats. Methods Female Sprague-Dawley rats were used. Ten-day-old rat pups underwent bladder sensitization via intravesical infusion of 0.2% acetic acid in saline with or without prior bladder desensitization with capsaicin. After 8 weeks, 3 groups of rats (control [group 1], bladder sensitization [group 2], and bladder desensitization [group 3]) underwent cystometry. Inflammation of bladder tissue and the expression of TRPV1 in bladder tissue and dorsal root ganglia (DRG) were also evaluated. Results The bladder sensitization group showed more frequent voiding contractions. TRPV1 expression in adult bladder tissue was elevated in group 2. TRPV1 mRNA levels in the bladder and DRG were significantly higher in group 2 than in group 1. Moreover, group 2 had significantly more DRG neurons (identified by uptake of the retrograde label Fast Blue) that exhibited TRPV1 immunoreactivity. Conclusions We found a significant association between neonatal bladder sensitization and persistent TRPV1 activity in adult rats. This is the first study to focus on the underlying pathogenesis of bladder overactivity from childhood to adulthood. Our findings could lead to the development of new strategies for the treatment and prevention of adult urinary symptoms arising from childhood urinary tract dysfunction
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