Spontaneous growth of polarizing refractory metal 'nano-fins'.

Traditional polymer polarizers degrade in harsh environments and at high temperatures, reducing the polarization effect. In contrast, polarizers produced with refractory metals have vastly improved thermal stability and resistance to harsh environments but are expensive to fabricate. Here we demonstrate prototype refractory metal wire grid polarizers produced by co-sputtering molybdenum and aluminum under specific conditions. Removal of the aluminum through selective dissolution enables the nanostructure array to transmit light. The polarization spans 500-1100 nm and the extinction ratio significantly increases to >100. Possessing broadband polarization and sufficient extinction ratios, the new polarizing film has potential applications in coatings for sunglasses, windows, pyrometers, scientific instruments, and LCD panels.

Sweet hyperopia: refractive changes in acute hyperglycemia.

PURPOSE: A prospective study was performed to evaluate refractive and ocular biometric changes in acute hyperglycemic status in patients with diabetes mellitus. METHODS: From January to August 2002, 48 eyes of 24 patients with persistent diabetes and a plasma glucose level>or=17 mmol/L or HbA1c>or=10.0% on admission were enrolled in this prospective study. Upon admission to Tri-Service General Hospital in Taipei, Taiwan, these patients underwent intensive glycemic control. The basic ophthalmic examinations, including visual acuity, intraocular pressure measurement, slit lamp, and fundus examinations, were conducted. The ocular parameters including refraction, anterior chamber depth, lens thickness, axial length, mean keratometry, and thinnest corneal thickness were evaluated by A-mode scan and Orbscan II. Each patient underwent clinical follow-up visits at 1, 2, and 4 weeks after the acute hyperglycemic episode. RESULTS: Of the 24 patients, 18 were male and 6 were female. The mean age of the patients was 55 years (range: 38 to 69). Comparing the refractive status on admission and at week 4, the authors found that 8 cases (16 eyes, 33%) showed hyperopia during hyperglycemia (+1.9+/-0.8 D), but in the other 16 cases (32 eyes, 67%), there were no significant changes. In addition, there were also no significant changes in anterior chamber depth, lens thickness, axial length, thinnest corneal thickness, or mean keratometry in the follow-up period. CONCLUSIONS: Transitory hyperglycemia produces hyperopia. The alteration in refractive index in the lens may contribute to the hyperopic change, but no change of ocular biometrics in lens or cornea is observed.

Kinetics and products of the degradation of chitosan by hydrogen peroxide.

Low concentrations of hydrogen peroxide induced random degradation of partially deacetylated chitin and chitosan. Average molecular weight decreased in accordance with first-order kinetics. The degradation rate was much faster than that of the ultrasonic degradation, and it was comparable to that of the enzymatic hydrolysis of chitosan. Chain-end scissions occurred after chitosan was degraded severely and produced significant amounts of oligosaccharides at temperatures > or =80 degrees C. Universal calibration moderated the change in molecular weight more closely than that calculated by the usual calibration using pullulan standards. Trace amounts of transition metal ions and the amino groups in chitosan were critical to the breakdown of the beta-1,4 glycosidic linkages. HPLC results of glucosamine and chito-oligosaccharides could be characterized by correlating the logarithmic values of retention time with the degrees of polymerization. The formation of glucosamine and chito-oligosaccharides depended on the concentration of H(2)O(2), temperature, and the physicochemical property of chitin/chitosan.

Subconjunctival retention of C3F8 gas increased the success rates of trabeculectomy in young people.

In this study, the effect of subconjunctival retention of perfluoropropane (C3F8) gas on trabeculectomy was evaluated to determine if this maneuver would increase the success rate of the surgery. Thirty-two patients (under 35 years old) with a diagnosis of primary open-angle glaucoma or steroid-induced glaucoma were randomized into two groups to receive trabeculectomy: Group A (trabeculectomy alone, 16 eyes) and Group B (trabeculectomy with subconjunctival retention of 0.5 mL pure C3F8 gas, 16 eyes). The results showed that the typical appearance of a subconjunctivally retained C3F8 filtering bleb is highly distended in the first two weeks after surgery, followed by flattening and diffusing gradually. The average retention time of C3F8 gas within the subconjunctival space is 28 +/- 6 days. A higher success rate was noted in Group B than in Group A (94% versus 50%, p = 0.016) at a mean follow-up time of 12 months. However, there were no differences in complication rates and results of final visual acuity between the two groups (both groups had two patients lose more than two lines of vision, p = 1.0). Our study suggests that subconjunctival retention of C3F8 gas increases the success rate of trabeculectomy in young people in the intermediate-term (12 months) follow-up period.

Predictive value of endometrial sonography in ovulation induction for intrauterine insemination.

This prospective study was undertaken to evaluate the prognostic value of the endometrial sonographic pattern on the day of human chorionic gonadotropin (hCG) administration in patients who underwent intrauterine insemination. The endometrial sonographic patterns were classified as homogenous, hyperechogenic (A), intermediate isoechogenic (B) and multiple-layered "triple-line" (C). Type A had no pregnancies, whereas type B had a 20% fecundity rate and type C had a 21.1% fecundity rate. The continuing pregnancy rate was 10% in type B, as compared to 19.3% in type C. The data suggest that the endometrial sonographic pattern on the day of hCG administration may be of predictive value regarding fecundity and continuing pregnancy in the intrauterine insemination cycle.

Comparison of laparoscopically assisted vaginal hysterectomy and abdominal hysterectomy in taiwan.

In order to clarify the feasibility of laparoscopically assisted vaginal hysterectomy (LAVH) using a not-for-extra charge instrument and to determine its cost-effectiveness in the Taiwan national health care system, we designed a prospective comparison which recruited candidates with nonmalignant uterine tumors prepared for hysterectomy to assess treatment by the laparoscopic versus the laparotomic approach. There were 144 patients in the laparoscopic group and 157 patients in the laparotomic group. The two groups were similar in characteristics. A total of 138 LAVHs were completed with six conversions (4.2%) to abdominal hysterectomy. Intraoperatively, the mean operating time in the LAVH group was longer than in the laparotomic group (134 vs 112 minutes, p < 0.001). No statistically significant differences were found between the two groups in mean estimated blood loss (260 vs 259 mL) and complications (5.8 vs 4.5%). Postoperatively, mean flatulence-relief time (27.4 vs 31.3 hours) and intramuscular meperidine requirements (1.6 vs 2.5 ampoules, 1 ampoule = 50 mg) were significantly less with LAVH. There were no differences in mean hemoglobin levels (10.7 vs 10.9 g/dL), complications (9.4 vs 13.4%, p = 0.288), or hospital stay (4.9 vs 5.2 days, p = 0.058). The mean total hospital charges (NT$48,390 vs 41,649) and insurance-paid costs (NT$43,992 vs 38,389) were significantly greater in the LAVH group. In conclusion, LAVH when performed by an experienced laparoscopist and for adequately selected patients, permits a better short-term convalescence, but is more expensive compared with conventional abdominal hysterectomy.

Intermediate outcomes of Ahmed glaucoma valve surgery in Asian patients with intractable glaucoma.

OBJECTIVE: To evaluate the efficacy and safety of Ahmed glaucoma valve (AGV) implantation in Asian patients with refractory glaucoma. METHODS: The study was a retrospective interventional case series conducted at a single institution between January 2004 and January 2006. The study population included 91 patients (91 eyes). RESULTS: A total of 70 patients were successfully treated (74.5%). Postoperatively, the median intraocular pressures declined significantly to 13 mm Hg (interquartile range: 10-20 mm Hg) on day 1 (P<0.001) and 17 mm Hg (interquartile range: 12-19 mm Hg) at the last follow-up examination (P<0.001). The cumulative probability of success according to Kaplan-Meier life-table analysis was 74% at 12 months and 43% at 2 years. Hazard of failure increased slightly with age, HR: 1.03 (95% confidence interval (CI)=1.00-1.05; P=0.044). The most common complication was hyphaemia at 12.77%. There were no serious complications involving loss of visual acuity or sight. CONCLUSIONS: AGV implantation is an acceptable treatment for refractory glaucoma in high-risk patients with few additional options.

Developing a culturally relevant bioethics for Asian people.

Because of cultural differences between East and West, any attempt at outright adaptation of Western ideas in Asia will undoubtedly encounter problems, if not rejection. Transferring an idea from one place to another is just like transplanting an organ from a donor to a recipient--rejection is to be expected. Human cultures respond to new ideas from different value systems in very much the same way. Recently, biomedical ethics has received much attention in Asia. Fundamental advances in medicine have motivated medical scientists to look at the ethical issues arising from this progress. Will the principles upheld by the bioethicists in the West meet the challenge in Asia? This article argues that Asian bioethicists must develop a bioethics responding to their own cultural contexts. If Western principles are adopted, then they must be re-interpreted and even modified, if necessary, in light of Asian beliefs.

Multivariate analyses of the relationship between umbilical cord length and obstetric outcome.

To investigate the clinical significance of umbilical cord length in human pregnancies, 1087 deliveries at Kaohsiung Chang Gung Memorial Hospital from May 1995 to August 1995 were studied. Our data showed that male fetuses had longer cord length than female and vertex presentation had longer cord length than breech presentation. The cord length and placental weight were significantly related to the birth weight. We found that: 1) only intrauterine growth retardation was associated with the increased risk of fetal distress; 2) secondary arrest of labor and advanced gestational age were correlated with meconium stain; and 3) birth weight and presence of meconium stain were correlated with the secondary arrest (p < 0.05). However, there was no significant correlation between umbilical cord length and fetal well-being. As a result of multivariate analyses, we conclude that the umbilical cord length does not significantly correlate with either maternal age, gestational age (> or = 28 weeks), parity fetal outcome or intrauterine fetal well-being. Birth weight is the only characteristic that is correlated with cord length.