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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Skeletal radiology 29 (2000), S. A302 
    ISSN: 1432-2161
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2161
    Keywords: Key words Tibia ; Intracortical osteosarcoma ; Osteoblastic type ; Calcified spherules ; Oncogenic rickets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Intracortical osteosarcoma is the rarest variant of osteosarcoma, occurring within, and usually confined to, the cortical bone. Oncogenic osteomalacia, or rickets, is an unusual clinicopathologic entity in which vitamin D-resistant osteomalacia, or rickets, occurs in association with some tumors of soft tissue or bone. We present a case of oncogenic rickets associated with intracortical osteosarcoma of the tibia in a 9-year-old boy, whose roentgenographic abnormalities of rickets disappeared and pertinent laboratory data except for serum alkaline phosphatase became normal after surgical resection of the tumor. Histologically, the tumor was an osteosarcoma with a prominent osteoblastic pattern. An unusual microscopic feature was the presence of matrix mineralization showing rounded calcified structures (calcified spherules). Benign osteoblastic tumors, such as osteoid osteoma and osteoblastoma, must be considered in the differential diagnosis because of the relatively low cellular atypia and mitotic activity of this tumor. The infiltrating pattern with destruction or engulfment of normal bone is a major clue to the correct diagnosis of intracortical osteosarcoma. The co-existing radiographic changes of rickets were due to the intracortical osteosarcoma.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2161
    Keywords: Diagnosis ; Scintigraphy ; Soft tissue tumor ; Extra-abdominal fibromatosis ; Technetium-99m
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of this study was to investigate technetium-99m pertechnetate (Tc-99m) as a tumor-scanning agent in patients with extra-abdominal fibromatosis, and to establish the sensitivity of this type of scintigraphy. Eleven patients with extra-abdominal fibromatosis were studied: all but one having postsurgical recurrences. Of the 11 patients, diagnosed histologically, 5 underwent repeated Tc-99m scintigraphic follow-up examinations. The injected 370 MBq Tc-99m gave us an early scintigram within 10 min and a delayed one 2 h later. For adequate comparison, the region of interest (ROI) of the scintigram was placed over the tumor. The tumor-to-background (T/BG) count ratio was computed. Extra-abdominal fibromatoses, even recurrences, were demonstrated scintigraphically in both the early and the delayed phase, in all 11 patients. The average T/BG ratio was 2.11 in the early scintigram and 2.15 in the delayed one. The sensitivity and the specificity were both 100%. Tc-99m scintigraphy has proved useful in detecting extra-abdominal fibromatoses and in the follow-up of patients.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1436-2023
    Keywords: Key words Malignant pelvic bone tumors ; Multidisciplinary treatment ; Surgical margins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The prognosis for malignant pelvic bone tumors is worse than that for malignant bone tumors of the extremities because definitive surgery in the pelvis is often difficult to accomplish. The results for eight patients who were treated consecutively with a multidisciplinary approach, from 1990, were analyzed. The histologic diagnosis was osteosarcoma in five patients, chondrosarcoma in two, and Ewing's sarcoma in one. Five lesions arose in the ilium and three in the pubis. The extraosseous tumors decreased in size and/or were encapsulated as a result of preoperative chemotherapy in six patients, four of these achieving a wide surgical margin. With respect to tumor location and surgical margin, all five lesions in the ilium involved the sacrum, four of these being resected with an inadequate margin. The three lesions in the pubis were resected with an adequate margin. Local recurrence was observed in two patients who had been treated with an inappropriate margin. During the period between 18 and 57 months after the first operation, five patients were continuously free of disease and one was still alive but had lung metastases. Our results indicate that a patient's chances of definitive surgery may be enhanced by a multidisciplinary approach, although the management of sacroiliac involvement remains challenging.
    Type of Medium: Electronic Resource
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  • 5
    Publication Date: 2020-08-05
    Description: Energy field is one of the practical areas to which optimization can contribute significantly. In this chapter, the application of mixed-integer linear programming (MILP) approaches to optimal design and operation of distributed energy systems is described. First, the optimal design and operation problems are defined, and relevant previous work is reviewed. Then, an MILP method utilizing the hierarchical relationship between design and operation variables is presented. In the optimal design problem, integer variables are used to express the types, capacities, numbers, operation modes, and on/off states of operation of equipment, and the number of these variables increases with those of equipment and periods for variations in energy demands, and affects the computation efficiency significantly. The presented method can change the enumeration tree for the branching and bounding procedures, and can search the optimal solution very efficiently. Finally, future work in relation to this method is described.
    Language: English
    Type: bookpart , doc-type:bookPart
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  • 6
    Publication Date: 2020-08-05
    Description: Optimization approaches based on the mixed-integer linear programming (MILP) have been utilized to design energy supply systems. In this paper, an MILP method utilizing the hierarchical relationship between design and operation is extended to search not only the optimal solution but also suboptimal ones which follow the optimal one without any omissions, what are called K-best solutions, efficiently in a multiobjective optimal design problem. At the upper level, the values of design variables for the K-best solutions are searched by the branch and bound method. At the lower level, the values of operation variables are optimized independently at each period by the branch and bound method under the values of design variables given tentatively. Incumbents for the K-best solutions and an upper bound for all the values of the objective function for the K-best solutions are renewed if necessary between both the levels. This method is implemented into a commercial MILP solver. A practical case study on the multiobjective optimal design of a cogeneration system is conducted, and the validity and effectiveness of the method are clarified.
    Language: English
    Type: conferenceobject , doc-type:conferenceObject
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  • 7
    Publication Date: 2020-08-05
    Description: To attain the highest performance of energy supply systems, it is necessary to rationally determine types, capacities, and numbers of equipment in consideration of their operational strategies corresponding to seasonal and hourly variations in energy demands. In the combinatorial optimization method based on the mixed-integer linear programming (MILP), integer variables are used to express the selection, numbers, and on/off status of operation of equipment, and the number of these variables increases with those of equipment and periods for variations in energy demands, and affects the computation efficiency significantly. In this paper, a MILP method utilizing the hierarchical relationship between design and operation variables is proposed to solve the optimal design problem of energy supply systems efficiently: At the upper level, the optimal values of design variables are searched by the branch and bound method; At the lower level, the values of operation variables are optimized independently at each period by the branch and bound method under the values of design variables given tentatively during the search at the upper level; Lower bounds for the optimal value of the objective function to be minimized are evaluated, and are utilized for the bounding operations at both the levels. This method is implemented into open and commercial MILP solvers. Illustrative and practical case studies on the optimal design of cogeneration systems are conducted, and the validity and effectiveness of the proposed method are clarified.
    Language: English
    Type: article , doc-type:article
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  • 8
    Publication Date: 2020-08-05
    Description: In designing energy supply systems, designers are requested to rationally determine equipment types, capacities, and numbers in consideration of equipment operational strategies corresponding to seasonal and hourly variations in energy demands. However, energy demands have some uncertainty at the design stage, and the energy demands which become certain at the operation stage may differ from those estimated at the design stage. Therefore, designers should consider that energy demands have some uncertainty, evaluate the performance robustness against the uncertainty, and design the systems to heighten the robustness. Especially, this issue is important for cogeneration plants, because their performances depend significantly on both heat and power demands. Although robust optimal design methods of energy supply systems under uncertain energy demands were developed, all of them are based on linear models for energy supply systems. However, it is still a hard challenge to develop a robust optimal design method even based on a mixed-integer linear model. At the first step for this challenge, in this paper, a method of evaluating the performance robustness of energy supply systems under uncertain energy demands is proposed based on a mixed-integer linear model. This problem is formulated as a bilevel mixed-integer linear programming one, and a sequential solution method is applied to solve it approximately by discretizing uncertain energy demands within their intervals. In addition, a hierarchical optimization method in consideration of the hierarchical relationship between design and operation variables is applied to solve large scale problems efficiently. Through a case study on a gas turbine cogeneration plant for district energy supply, the validity and effectiveness of the proposed method and features of the performance robustness of the plant are clarified.
    Language: English
    Type: conferenceobject , doc-type:conferenceObject
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  • 9
    Publication Date: 2020-08-05
    Description: To attain the highest performance of energy supply systems, it is necessary to rationally determine types, capacities, and numbers of equipment in consideration of their operational strategies corresponding to seasonal and hourly variations in energy demands. In the combinatorial optimization method based on the mixed-integer linear programming (MILP), integer variables are used to express the selection, numbers, and on/off status of operation of equipment, and the number of these variables increases with those of equipment and periods for variations in energy demands, and affects the computation efficiency significantly. In this paper, a MILP method utilizing the hierarchical relationship between design and operation variables is proposed to solve the optimal design problem of energy supply systems efficiently: At the upper level, the optimal values of design variables are searched by the branch and bound method; At the lower level, the values of operation variables are optimized independently at each period by the branch and bound method under the values of design variables given tentatively during the search at the upper level; Lower bounds for the optimal value of the objective function are evaluated, and are utilized for the bounding operations at both the levels. This method is implemented into open and commercial MILP solvers. Illustrative and practical case studies on the optimal design of cogeneration systems are conducted, and the validity and effectiveness of the proposed method are clarified.
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/pdf
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  • 10
    Publication Date: 2020-11-26
    Description: The mixed-integer linear programming (MILP) method has been applied widely to optimal design of energy supply systems. A hierarchical MILP method has been proposed to solve such optimal design problems effi- ciently. As one of the strategies to enhance the computation efficiency furthermore, a method of reducing model by time aggregation has been proposed to search design candidates accurately and efficiently in the relaxed optimal design problem at the upper level. In this paper, the hierarchical MILP method and model reduction by time aggregation are applied to the multiobjective optimal design. In applying the model reduc- tion, the methods of clustering periods by the order of time series, based on an operational strategy, and by the k-medoids method are applied. As a case study, the multiobjective optimal design of a gas turbine cogeneration system with a practical configuration is investigated by adopting the annual total cost and pri- mary energy consumption as the objective functions to be minimized simultaneously, and the clustering methods are compared with one another in terms of the computation efficiency. It turns out that the model reduction by any clustering method is effective to enhance the computation efficiency when importance is given to minimizing the first objective function. It also turns out that the model reduction only by the k- medoids method is effective very limitedly when importance is given to minimizing the second objective function.
    Language: English
    Type: conferenceobject , doc-type:conferenceObject
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