High-Speed CMOS Switch Designs for Free-Space Optoelectronic MINs

We present the theory, experimental results, and analytical modeling of high-speed CMOS switches, with a 2-D layout, suitable for the implementation of packet-switched free-space optoelectronic Multistage Interconnection Networks (MINs). These switches are fully connected, bi-directional, and scaleable. The first design is a proof of concept of the half-switch, which is a two-to-one multiplexer, and the 2-D layout. The second design introduces a novel self-routing concept, with contention detection and packet drop-and-resend capabilities. It uses three-valued logic, with 2.5V being the third value for a 5V power supply. Simulations show that for a 0.8 µm CMOS technology the switches can operate at speeds up to 250 Mbits/sec. Scaled-down versions of both designs have been successfully implemented in 2.0 µm CMOS. The analytical modeling of the switches show that large scale free-space optoelectronic MINs using this concept could offer close to Terabit/sec throughput capabilities and ver..

Esener, “Optimization and theoretical modeling of polymer microlens arrays fabricated with the hydrophobic effect

High-performance polymer microlens arrays were fabricated by means of withdrawing substrates of patterned wettability from a monomer solution. The f-number ͑f # ͒ of formed microlenses was controlled by adjustment of monomer viscosity and surface tension, substrate dipping angle and withdrawal speed, the array fill factor, and the number of dip coats used. An optimum withdrawal speed was identified at which f # was minimized and array uniformity was maximized. At this optimum, arrays of f͞3.48 microlenses were fabricated with one dip coat with uniformity of better than ⌬f͞f ϳ Ϯ3.8%. Multiple dip coats allowed for production of f͞1.38 lens arrays and uniformity of better than ⌬f͞f ϳ Ϯ5.9%. Average f # s were reproducible to within 3.5%. A model was developed to describe the fluid-transfer process by which monomer solution assembles on the hydrophilic domains. The model agrees well with experimental trends

Isolated Retroperitoneal Hydatid Cyst Invading Splenic Hilum

Introduction. Hydatid disease (HD) is an infestation that is caused by the larval stage of Echinococcus granulosus. The liver is affected in approximately two-thirds of patients, the lungs in 25%, and other organs in a small proportion. Primary retroperitoneal hydatid cyst is extremely rare. The most common complaint is abdominal pain; however, the clinical features of HD may be generally dependent on the location of the cyst. Case Presentation. A 43-year-old female was admitted with the complaint of abdominal pain. Her physical examination was normal. Computed tomography (CT) revealed a 17 × 11 cm cystic lesion, with a thick and smooth wall that is located among the left liver lobe, diaphragm, spleen, tail of the pancreas, and transverse colon and invading the splenic hilum. Total cystectomy and splenectomy were performed. Pathological examination was reported as cyst hydatid. Discussion. Cysts in the peritoneal cavity are mainly the result of the spontaneous or traumatic rupture of concomitant hepatic cysts or surgical inoculation of a hepatic cyst. Serological tests contribute to diagnosis. In symptomatic and large hydatid peritoneal cysts, surgical resection is the only curative treatment. Total cystectomy is the gold standard. Albendazole or praziquantel is indicated for inoperable and disseminated cases. Percutaneous aspiration, injection, and reaspiration (PAIR) technique is another nonsurgical option

Isolated metastasis of uterine leiomyosarcoma to the pancreas: Report of a case and review of the literature

AbstractINTRODUCTIONMetastatic tumors of the pancreas are uncommon and rarely detectable clinically. Metastases to the pancreas are rare. We present a patient with pancreatic metastases from a leiomyosarcoma of the uterus and review the literature about the clinical features of pancreatic metastasis and its surgical management.PRESENTATION OF CASEA 40-year-old woman, who underwent hysterectomy, left oophorectomy, omentectomy and lymp node dissection for leiomyosarcoma of the uterus. At the follow up, the patient complained of non-specific abdominal discomfort. Preoperative diagnosis were pancreatic pseudocyst, cystadenoma or cystadenocarcinoma. At laparotomy, a cystic mass was found in the tail of the pancreas which was invased to the transverse colon mesenterium and the spleen. Distal pancreatectomy with splenectomy and transverse colon resection was performed. Histologically, the tumor was evaluated as poorly differentiated leiomyosarcoma.DISCUSSIONMetastatic lesions of the pancreas are uncommon and less than 2% of all pancreatic malignancies. However a few cases of leiomyosarcoma with metastases to the pancreas have been reported in the literature. Before deciding that the lesion in the pancreas was metastasis, primary leiomyosarcoma of the pancreas had to be ruled out. Histologically, leiomyosarcoma of the pancreas contains interlacing spindle cells with varying degrees of atypia and pleomorphism. The surgical approach to the pancreatic metastases must be aimed complete excision of the tumor with a wide negative margin of clear tissue and maximum preservation of pancreatic remnant if possible.CONCLUSIONIn the absence of widespread metastatic disease, aggressive surgical approach with negative margins must be aimed

Antimicrobial resistance in Gram-negative hospital isolates: Results of the Turkish HITIT-2 surveillance study of 2007

Resistance rates to amikacin, ciprofloxacin, ceftazidime, cefepime, imipenem, cefoperazone/sulbactam and piperacillin/tazobactam in Escherichia coli (n = 438), Klebsiella pneumoniae (n = 444), Pseudomonas aeruginosa (n = 210) and Acinetobacter baumanni (n =200) were determined with E-test in a multicenter surveillance study (HITIT-2) in 2007. ESBL production in Escherichia coli and K. pneumoniae was investigated following the CLSI guidelines. Overall 42.0% of E.coli and 41.4% of K. pneumoniae were ESBL producers. In E. coli, resistance to imipenem was not observed, resistance to ciprofloxacin and amikacin was 58.0% and 5.5% respectively. In K. pneumoniae resistance to imipenem, ciprofloxacin and amikacin was 3.1%, 17.8% 12.4% respectively. In P. aeruginosa the lowest rate of resistance was observed with piperacillin/tazobactam (18.1%). A. baumanni isolates were highly resistant to all the antimicrobial agents, the lowest level of resistance was observed against cefoperazone/sulbactam (52.0%) followed by imipenem (55.5%). This study showed that resistance rates to antimicrobials are high in nosocomial isolates and show variations among the centers