Generalized mathematical models in design optimization

The theory of optimality conditions of extremal problems can be extended to problems continuously deformed by an input vector. The connection between the sensitivity, well-posedness, stability and approximation of optimization problems is steadily emerging. The authors believe that the important realization here is that the underlying basis of all such work is still the study of point-to-set maps and of small perturbations, yet what has been identified previously as being just related to solution procedures is now being extended to study modeling itself in its own right. Many important studies related to the theoretical issues of parametric programming and large deformation in nonlinear programming have been reported in the last few years, and the challenge now seems to be in devising effective computational tools for solving these generalized design optimization models

GIST suture-line recurrence at a gastrojejunal anastomosis 8 years after gastrectomy: can GIST ever be described as truly benign? A case report

We present the case of a 71 year old man with recurrence of a Gastro Intestinal Stromal Tumour (GIST) at the gastrojejunal anastomosis eight years following partial gastrectomy for a very small primary gastric GIST. He presented acutely on both occasions with haemodynamic shock secondary to massive haematemesis. During his initial presentation in 2001, an emergency laparotomy was performed, demonstrating a pre-pyloric ulcerative lesion. The histopathology was in keeping with a diagnosis of a gastric GIST with a < 2 cm tumour, with <5 mitosis per 50/HPF, no signs of necrosis and invasion limited to the mucosa. Eight years later the same patient presented with a similar clinical picture of haemodynamic instability secondary to haematemesis. Emergency endoscopy showed an irregularly shaped elevated lesion on the gastrojejunostomy line suggestive of recurrence. He subsequently underwent completion gastrectomy and the histology revealed a 0.8 cm GIST tumour composed of spindle cells with <5 mitosis per 50/HPF, tumor invasion into the submucosa and positive expression of c-kit and SMA. The patient remains recurrence free 18 months post surgery. The literature suggests that tumour size, mitotic rate and tumour site are the most important predictive factors of recurrence. Additional features such as the presence of necrosis, local tumour invasion and positive resection margins, can also influence recurrence rates. In this case the lesion was a gastric GIST, very small (<2 cm), had low proliferation rate (<5 mitosis/HPF), lacked necrosis and was limited to the mucosa. Recurrence of such a primary GIST at the anastomotic line, eight years after initial resection has never been demonstrated among review of several thousand primary GISTs. This case highlights how even the most innocent GISTs can never be described as truly benign

Project MAXWELL: Towards Rapid Realization of Superior Products

We describe a new methodology for the design and manufacture of mechanical components. The methodology is a synergism of a new, mathematically rigorous procedure for the concurrent design of shape and material composition of components, and a new manufacturing process called MD* for their realization. The concurrent design strategy yields information about the global shape of the component and its material composition. The fabrication of such designs with novel microstructural configurations require unconventional manufacturing processes. MD* is a shape deposition process for the free-form fabrication of parts from single or composite materials and is ideally suited for realizing the aforementioned designs. Project MAXWELL, therefore, promotes the use of layered manufacturing beyond prototyping tasks and offers the possibility of their integration into the mainstream product development and fabrication process..Mechanical Engineerin

Accuracy considerations in approximate reanalysis of structures

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76782/1/AIAA-2000-4751-508.pd

Pleomorphic Giant Cell Carcinoma of the Pancreas with Hepatic Metastases—Initially Presenting as a Benign Serous Cystadenoma: A Case Report and Review of the Literature

Introduction. Pleomorphic giant cell pancreatic cancer is a very rare and aggressive pancreatic neoplasm. A case of pleomorphic giant cell pancreatic cancer presenting as a cystic lesion and in association with a serous cystadenoma presents a unique case which has not been described before. Case Presentation. A 44-year-old alcoholic man presented with abdominal pain, vomiting, and weight loss. Initially, imaging suspected a pancreatic pseudocyst measuring 4.2 cm. Endoscopic ultrasound- (EUS-) guided fine-needle aspiration revealed a serous cystadenoma. With conservative intervention only (fluid resuscitation, analgesia, and antiemetics) the patient improved and was discharged under close observation. Follow-up scan at four months revealed minimal change. Three months later, he was admitted acutely. Repeat scans demonstrated mild cyst enlargement with new liver lesions. Laparoscopic biopsy revealed pleomorphic giant cell carcinoma with the organ of origin the pancreas. Conclusion. This unusual case highlights the challenges in managing pancreatic cystic lesions and emphasizes the importance of considering less common forms of pancreatic cystic masses when the findings are atypical for the presentation. Surgical excision in these cases over conservative steps may be the most appropriate management

Coexistence of gastrointestinal stromal tumor (GIST) and colorectal adenocarcinoma: A case report

<p>Abstract</p> <p>Background</p> <p>Gastrointestinal stromal tumors (GIST) represent the most common mesenchymal tumors of the digestive tract. Over the last ten years the management of GISTs has dramatically altered but their coexistence with other gasrointesinal tumors of different histogenesis presents a special interest. The coexistence of GISTs with other primaries is usually discovered incidentally during GI surgery for carcinomas.</p> <p>Case presentation</p> <p>We present here, a case of a 66-year-old patient with intestinal GIST and a synchronous colorectal adenocarcinoma discovered incidentally during surgical treatment of the recurrent GIST. Immunohistochemical examination revealed the concurrence of histologically proved GIST (strongly positive staining for c-kit, vimentin, SMA, and focal positive in S-100, while CD-34 was negative) and Dukes Stage C, (T3, N3, M0 according the TNM staging classification of colorectal cancer).</p> <p>Conclusion</p> <p>The coexistence of GIST with either synchronous or metachronous colorectal cancer represents a phenomenon with increasing number of relative reports in the literature the last 5 years. In any case of GIST the surgeon should be alert to recognize a possible coexistent tumor with different histological origin and to perform a thorough preoperative and intraoperative control. The correct diagnosis before and at the time of the surgical procedure is the cornerstone that secures the patients' best prognosis.</p

Optimal Design of Commercial Vehicle Systems Using Analytical Target Cascading

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97129/1/AIAA2012-5524.pd

Application of a product platform design process to automotive powertrains

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77031/1/AIAA-2000-4849-139.pd

Sequentially decomposed programming

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76276/1/AIAA-1996-4008-190.pd

A modification to Jones' global optimization algorithm for fast local convergence

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77127/1/AIAA-1998-4751-286.pd