1,721,045 research outputs found
Metabolic Evolution of Mannheimia succinicproducens for the Succinate Production and its Proteomic Characteristics.
No full textThermoelastic analysis of a kick motor nozzle incorporating spatially reinforced composites
No full textThe mechanical and thermal properties of spatially reinforced composites are predicted using volume average and rules of mixture of the rods and matrix properties for stiffness, thermal conductivity, and coefficient of thermal expansion. The distribution of Young's modulus, thermal conductivity, and coefficient of thermal expansion for three-dimensional/four-dimensionaI spatially. reinforced composites are demonstrated. The study examines the elastic behavior, the temperature distribution, and the thermoelastic behavior of a kick motor nozzle, which includes a carbon/carbon spatially reinforced composite as a throat part. The elastic deformation of the nozzle composed of three-dimensional carbon/carbon spatially reinforced composite shows asymmetry, whereas the elastic deformation of four-dimensional carbon/carbon spatially reinforced composite nozzle shows uniformity in the circumferential, direction. The thermoelastic deformations of both the three- and four-dimensional spatially reinforced composite nozzles are uniform in the circumferential direction. The deformation of the three-dimensional spatially reinforced composite nozzle is slightly smaller than that of the four-dimensional spatially reinforced composite nozzle in the nozzle throat. Circumferential stress is the critical stress component of the kick motor nozzle
Synthesis, structures and antitumor activity of the first crown ester-linked bipyridyl platinum complexes
No full textThree new crown ester-linked bipyridine homologs with three, four or five ethylene glycol units, which are bulky and soluble in both hydrophilic and lipophilic;media, were synthesized. The reaction of the appropriate macrocycles with K2PtCl4 in water gave yellow cisplatin analogs in good yield. These complexes were converted to carboplatin analogs by exchange of the leaving group. All the compounds were characterized by elemental analysis and various spectroscopic methods. Carboplatin analogs showed good solubility in both hydrophilic and lipophilic media. The crystal structure of 2c, the carboplatin analog with macrocycles containing five ethylene glycol units, was determined by X-ray diffraction: space group P (1) over bar, a = 9.798(1), b = 12.580(3), c = 13.945(2) Angstrom, alpha =108.61(2), beta = 94.59(1), gamma = 97.42(2)degrees, Z = 2, R = 0.0618. Some of platinum complexes Showed a moderate cytotoxic effect on both murine leukemia L1210 and P388 even though they do not have any NH proton. (C) 1999 Elsevier Science Inc. All rights reserved.Korea Research Foundation and the Korea Science and Engineering Foundatio
PERFORMANCE COMPARISON OF SIGNATURE-BASED MULTIKEY ACCESS METHODS
No full textIn this paper we evaluate the performance of signature-based multikey access methods. We first establish a taxonomy of signature-based access methods; i.e. One-Path Single-Level (OPSL), Two-Path Single-Level (TPSL), One-Path Two-Level (OPTL), and Two-Path Two-Level (TPTL). Then we show from experimental results that two-path methods such as TPSL and TPTL achieve about 20-80 % gains on retrieval with the expense of 4-9 % more storage overhead, compared to OPSL and OPTL. Among two-path methods, TPTL outperforms TPSL on retrieval when the number of matching records is relatively small (less than 80); otherwise TPSL is better
Prediction of mechanical behavior of spatially reinforced composites for kick motor nozzle
No full textThis paper predicts the material properties of spatially reinforced composites (SRCs) and analyzes the mechanical behavior of a kick motor nozzle manufactured from that material. To find the appropriate SRC structure for the nozzle throat that satisfies given design conditions, the equivalent material properties of the SRC are predicted using the superposition of rod and matrix stiffnesses. The kick motor nozzle considered in this study consists of graphite or SRC as the throat part, carbon/phenol as the outer surface of the entrance part and inner surface of the expansion part, and steel as the outer surface of the expansion part. The material properties in arbitrary spatial directions are predicted and compared for 3-D and 4-D SRCs suitable to an axisymmetric kick motor nozzle structure. The 4-D SRC shows the smallest and uniform deformation in the nozzle throat, which has a favorable effect on the rocket thrust. The equivalent material properties of SRC are input to analyze the mechanical behavior of the kick motor nozzle using finite element method
Metabolic evolution of Mannheimia succiniciproducens for the succinate production and its proteomic characteristics
No full textDevelopment of the Enhanced Succinate-producing Strain by Metabolic Evolution and its Proteomic Characteristics
No full textEmergence of resistance to last-resort antimicrobials in bacteremia patients: A multicenter analysis of bloodstream pathogens in Korea
Full text linkThis study retrospectively reviewed the microbiological and clinical characteristics of patients diagnosed with bacteremia. Results from the first positive blood cultures were consecutively collected from July 2022 to June 2023 at a public secondary hospital, a university-affiliated tertiary hospital, and a university-affiliated secondary hospital in the Seoul metropolitan area. Antibiotic spectrum coverage (ASC) scores were calculated on the day the blood culture was performed (B0) and on two days after the blood culture results were reported (R+2). A total of 3,397 isolates were collected from 3,094 patients. Among these, 949 isolates obtained from 893 patients were classified as multidrug-resistant organisms (MDRO), including 170 imipenem-resistant gram-negative bacteria, 714 methicillin-resistant staphylococci, and 65 vancomycin-resistant enterococci. Interestingly, 13 and 42 gram-positive isolates were resistant to linezolid and quinupristin/dalfopristin, respectively. Moreover, 44 and 181 gram-negative isolates were resistant to amikacin and tigecycline, respectively. The proportion of ASC scores corresponding to broad or extremely broad-spectrum coverage was not significantly different between MDRO and non-MDRO groups at B0 (p = 0.0925). However, it increased in the MDRO group at R+2 (p <0.001). This study found that resistance to last-resort antimicrobials is emerging. Therefore, developing and incorporating molecular diagnostics using a wide range of resistance targets may facilitate rapid, tailored antimicrobial treatments
Thermo-elastic Analysis of a Kick Motor Nozzle Incorporating Sptaially Reinforced Composites
No full textDynamic construction of signature files based on frame sliced approach
No full textMany works on the signature file methods have been made in the past, but they are mainly for static environments. However, many recent applications in practice require a dynamic information storage structure that effectively supports insertions, deletions and updates. Though there are a few signature file techniques for dynamic environments, they suffer from serious performance degradation when query signature weights are light. In this paper, we propose a new dynamic signature file organization based on a frame sliced approach, called the hierarchical signature (HS) file. The HS file alleviates the problem of light query signature weights. We derive analytic performance evaluation models of the existing dynamic signature file methods and the proposed HS file. We also perform extensive experiments with various data distributions such as uniform, normal and exponential distributions. The relationships among various performance parameters are thoroughly investigated. We show through performance comparison based on analytic models and experiments that regardless of data distribution, the HS file significantly improves performance in both the retrieval time and the storage overhead over the other dynamic signature file methods proposed earlier. (C) 1999 Elsevier Science B.V. All rights reserved
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