Optimization of lightweight structure and supporting bipod flexure for a space mirror.

This article presents an optimization process for integrated optomechanical design. The proposed optimization process for integrated optomechanical design comprises computer-aided drafting, finite element analysis (FEA), optomechanical transfer codes, and an optimization solver. The FEA was conducted to determine mirror surface deformation; then, deformed surface nodal data were transferred into Zernike polynomials through MATLAB optomechanical transfer codes to calculate the resulting optical path difference (OPD) and optical aberrations. To achieve an optimum design, the optimization iterations of the FEA, optomechanical transfer codes, and optimization solver were automatically connected through a self-developed Tcl script. Two examples of optimization design were illustrated in this research, namely, an optimum lightweight design of a Zerodur primary mirror with an outer diameter of 566 mm that is used in a spaceborne telescope and an optimum bipod flexure design that supports the optimum lightweight primary mirror. Finally, optimum designs were successfully accomplished in both examples, achieving a minimum peak-to-valley (PV) value for the OPD of the deformed optical surface. The simulated optimization results showed that (1) the lightweight ratio of the primary mirror increased from 56% to 66%; and (2) the PV value of the mirror supported by optimum bipod flexures in the horizontal position effectively decreased from 228 to 61 nm.

A surgeon's help with the management of bowel problems related to gynecology is truly needed - comparison of two periods spanning 24 years.

OBJECTIVE: Colorectal surgeons are frequently on call to provide help to gynecologists who are managing bowel problems that occur either during or following gynecological surgery. This is a retrospective analysis of a single surgeon's experiences associated with such instances. The analysis focuses on whether there have been any changes in referral patterns, surgical techniques and/or results. MATERIALS AND METHODS: From July 1984 to June 2008, 282 patients were operated on by a single colorectal surgeon, for problems that were related to gynecology. These consisted of 137 patients operated on during the first 12-year period, from July 1984 to June 1996. During this first period, 85 patients were operated on for cervical cancer related problems, 39 patients were operated on for problems related to other gynecological malignancies and nine patients were operated on for iatrogenic bowel injury during surgery. During the second 12-year period, from July 1996 to June 2008, 145 patients were operated on. Of these, 85 patients were operated on for cervical cancer related problems, 44 patients were operated on for problems related to other gynecological malignancies and eight patients were operated on for iatrogenic bowel injury during surgery. RESULTS: During the first 12-year period, six operations were pelvic exenterations for primary gynecological malignancies or recurrences. One hundred and one patients received stomas during their first operation. Twenty-five patients encountered various complications. Postoperative death occurred in five patients. During the second 12-year period, 12 operations were pelvic exenterations for primary gynecological malignancies or recurrences. Eighty-seven patients received stomas during their first operation. Thirty-seven patients encountered various complications. Postoperative death occurred in six patients. CONCLUSION: Gynecological problems frequently involve the colon or rectum. Cervical cancer related problems remain the most common type necessitating help from a colorectal surgeon. In spite of advances in surgical management, stomas are still frequently unavoidable in order to cure a patient or improve the patient's quality of life. Appropriate management of problems by a colorectal surgeon in relation to gynecology is important and in the best interests of the patient.

Missed cancerous lesions in emergency laparoscopic surgery: retrospective study of 2074 cases.

Abdominal laparoscopy is a widely accepted surgical procedure effective even for acute abdominal ailments. However, one major concern in using abdominal laparoscopy is missed lesions, in the past this has not been adequately explored. The aim of this retrospective study, therefore, is to evaluate cancerous lesions that are missed during emergency laparoscopic surgeries. The medical records of 2074 patients who had a laparoscopy from March 1996 to April 2006 for acute abdomen symptoms, including diagnostic laparoscopy (n = 119), laparoscopic appendectomy (n = 1336), laparoscopic duodenorrhaphy (n = 30), and laparoscopic cholecystectomy (n = 589) were reviewed. Missed cancerous lesions included cecal cancer (n = 2), sigmoid cancer (n = 1), and jejunum lymphoma (n = 1). The incidence of missed cancerous lesions in an emergency laparoscopic surgery is 0.19%, mainly due to its lower tactile sensitivity compared to the direct hand palpation and masqueraded by inflammatory process. Therefore, careful observation is recommended for post-emergency laparoscopic patients and follow-up should be performed within three months, especially for patients with intra-abdominal and/or severe inflammation status.

Simplified small-scale backlight unit tester.

A novel design is the concept of using charge coupled device camera embedded with calibrated image processing algorithm as a two-dimensional luminance meter to measure the luminance and uniformity of small-scale backlight of unit. A small-scale backlight unit tester was successfully realized and performed to verify this concept.

Protecting a lens with air.

A novel design is the concept of preventing the camera lens from contamination of the particles by using "airwall." An experimental wireless video camera debris deflecting system was realized and performed to verify the concept. Functional tests have been successfully verified.

Prospective randomized comparison of oral sodium phosphate and polyethylene glycol lavage for colonoscopy preparation.

AIM: To compare the effectiveness, patient acceptability, and physical tolerability of two oral lavage solutions prior to colonoscopy in a Taiwanese population. METHODS: Eighty consecutive patients were randomized to receive either standard 4 L of polyethylene glycol (PEG) or 90 mL of sodium phosphate (NaP) in a split regimen of two 45 mL doses separated by 12 h, prior to colonoscopic evaluation. The primary endpoint was the percent of subjects who had completed the preparation. Secondary endpoints included colonic cleansing evaluated with an overall assessment and segmental evaluation, the tolerance and acceptability assessed by a self-administered structured questionnaire, and a safety profile such as any unexpected adverse events, electrolyte tests, physical exams, vital signs, and body weights. RESULTS: A significantly higher completion rate was found in the NaP group compared to the PEG group (84.2% vs 27.5%, P<0.001). The amount of fluid suctioned was significantly less in patients taking NaP vs PEG (50.13+/-54.8 cc vs 121.13+/-115.4 cc, P<0.001), even after controlling for completion of the oral solution (P = 0.031). The two groups showed a comparable overall assessment of bowel preparation with a rate of "good" or "excellent" in 78.9% of patients in the NaP group and 82.5% in PEG group (P = 0.778). Patients taking NaP tended to have significantly better colonic segmental cleansing relative to stool amount observed in the descending (94.7% vs 70%, P = 0.007) and transverse (94.6% vs 74.4%, P = 0.025) colon. Slightly more patients graded the taste of NaP as "good" or "very good" compared to the PEG patients (32.5% vs 12.5%; P = 0.059). Patients' willingness to take the same preparation in the future was 68.4% in the NaP compared to 75% in the PEG group (P = 0.617). There was a significant increase in serum sodium and a significant decrease in phosphate and chloride levels in NaP group on the day following the colonoscopy without any clinical sequelae. Prolonged (>24 h) hemodynamic changes were also observed in 20-35% subjects of either group. CONCLUSION: Both bowel cleansing agents proved to be similar in safety and effectiveness, while NaP appeared to be more cost-effective. After identifying and excluding patients with potential risk factors, sodium phosphate should become an alternative preparation for patients undergoing elective colonoscopy in the Taiwanese population.