On the Krylov subspace solutions of matrix equations in control theory

Includes bibliographical references (pages 100-103).This dissertation deals with numerical solutions of large and sparse matrix equations, such as the Lyapunov, Sylvester, and algebraic Riccati equations (both continuous and discrete-time) arising in control systems design and applications. Research on large-scale matrix computations is still at the developing stage and, in particular, only a very small number of methods have been developed for the large-scale solutions of the above matrix equations. Furthermore, most of the existing methods have some computational limitations. In this dissertation, we propose three new methods for these matrix equations: an Arnoldi-based divide-and-conquer method for the discrete Sylvester equation, a block Arnoldi method for the continuous-time Lyapunov and Sylvester equations, and a block Arnoldi method for the continuous-time algebraic Riccati equation. The divide-and-conquer method is based on exploitation of the sparsity pattern of one of the system matrices, and the other Arnoldi methods for the continuous-time Lyapunov, Sylvester, and algebraic Riccati equations are completely general purpose in the sense that they work with large matrices with arbitrary sparsity patterns. All these new methods are practical for restarting because these methods are such that the residuals after m fixed number of steps can be cheaply computed using information available after m steps. The results of our numerical experiments on practical data demonstrate that these methods are more efficient and accurate than their existing counterparts.Ph.D. (Doctor of Philosophy

Circulating levels of inflammation-associated miR-155 and endothelial-enriched miR-126 in patients with end-stage renal disease

Circulating microRNAs (miRNAs) may represent a potential noninvasive molecular biomarker for various pathological conditions. Moreover, the detection of circulating miRNAs can provide important novel disease-related information. In particular, inflammation-associated miR-155 and endothelial-enriched miR-126 are reported to be associated with vascular homeostasis. Vascular damage is a common event described in end-stage renal disease (ESRD). We hypothesized that miR-155 and miR-126 may be detectable in the circulation and serve as potential biomarkers for risk stratification. In this study, we assessed miR-155 and miR-126 in the plasma of 30 ESRD patients and 20 healthy controls using real-time quantification RT-PCR. The circulating levels of miR-155 and miR-126 were significantly reduced in patients with ESRD compared to healthy controls. However, there was no significant difference of circulating miR-155 and miR-126 levels between prehemodialysis and posthemodialysis patients. Furthermore, both circulating miR-126 and miR-155 correlated positively with estimated glomerular filtration rate (miR-126: r = 0.383, P = 0.037; miR-155: r = 0.494, P = 0.006) and hemoglobin (miR-126: r = 0.515, P = 0.004; miR-155: r = 0.598, P < 0.001) and correlated inversely with phosphate level (miR-126: r = -0.675, P < 0.001; miR-155: r = -0.399, P = 0.029). Pearson&#8217;s correlation was used to compare circulating levels of miRNAs with clinical parameters. These results suggested that circulating miR-155 and miR-126 might be involved in the development of ESRD. Further studies are needed to demonstrate the role of circulating miR-155 and miR-126 as candidate biomarkers for risk estimation

Durability of Slag-Cement Paste Containing Polyaluminum Chloride

The effect of polyaluminum chloride (PAC) on the durability, microstructure, and corrosion sensitivity of slag-cement pastes was investigated in this research. Various experimental tests were performed to assess the mechanical properties (compressive strength test), durability (rapid chloride migration test, water permeability test, capillary water absorption test, chloride binding test, accelerated carbonation test), microstructure (scanning electron microscopy, X-ray diffraction, mercury intrusion porosimetry), and corrosion sensitivity (accelerated corrosion sensitivity, initial chloride concentration). Experimental results showed that adding 1.5% PAC increased compressive strength by 77.0%, 53.8%, and 19.4% at 3, 7, and 28 days. Resistance to chloride migration, water permeation, capillary water absorption, and carbonation was improved. These results were consistent with the microstructural analysis, which showed that adding PAC facilitated the formation of Friedel\u27s salt and development of pore structure, which was the key factor for the improved durability of the slag-cement paste. Adding 1.5% PAC had a limited influence on the corrosion sensitivity despite introducing the additional chloride ions into the system. These results promote the further practical application of PAC

Picea glehnii Masters

原著和名: アカエゾマツ科名: マツ科 = Pinaceae採集地: 北海道 根室市 落石 (北海道 根室 落石)採集日: 1972/7/12採集者: 萩庭丈壽整理番号: JH035993国立科学博物館整理番号: TNS-VS-98599

Clinical status of patients 1 year after hospital discharge following recovery from COVID-19: a prospective cohort study

Abstract Background The long-term clinical status of coronavirus disease 2019 (COVID-19) in recovered patients remains largely unknown. This prospective cohort study evaluated clinical status of COVID-19 and explored the associated risk factors. Methods At the outpatient visit, patients underwent routine blood tests, physical examinations, pulmonary function tests, 6-min walk test, high-resolution computed tomography (CT) of the chest, and extrapulmonary organ function tests. Results 230 patients were analyzed. Half (52.7%) reported at least one symptom, most commonly fatigue (20.3%) and sleep difficulties (15.8%). Anxiety (8.2%), depression (11.3%), post-traumatic symptoms (10.3%), and sleep disorders (26.3%) were also reported. Diffusion impairments were found in 35.4% of the patients. Abnormal chest CT scans were present in 63.5% of the patients, mainly reticulation and ground-glass opacities. Further, a persistent decline in kidney function was observed after discharge. SARS-CoV-2-specific antibodies of IgA, IgG, and IgM were positive in 56.4%, 96.3%, and 15.2% of patients, respectively. Multivariable logistic regression showed that disease severity, age, and sex were closely related to patient recovery. Conclusions One year after hospital discharge, patients recovered from COVID-19 continued to experience both pulmonary and extrapulmonary dysfunction. While paying attention to pulmonary manifestations of COVID-19, follow-up studies on extrapulmonary manifestations should be strengthened