Ultrabroadband supercontinuum generation in a CMOS-compatible platform.

We demonstrate supercontinuum generation spanning 1.6 octaves in silicon nitride waveguides. Using a 4.3 cm-long waveguide, with an effective nonlinearity of γ=1.2 W(-1) m(-1), we generate a spectrum extending from 665 nm to 2025 nm (at -30 dB) with 160 pJ pulses. Our results offer potential for a robust, integrated, and low-cost supercontinuum source for applications including frequency metrology, optical coherence tomography, confocal microscopy, and optical communications.

Bilateral tubal pregnancies after tubal sterilization.

Bilateral tubal pregnancies are a rare variety of ectopic gestation. Tubal sterilization has become an important cause of tubal pregnancy. To our knowledge, this is the first case report of a twin gestation resulting in bilateral tubal pregnancies after a modified Pomeroy tubal sterilization.

Laparoscopic treatment of symptomatic diaphragmatic endometriosis: a case report.

Extreme caution and meticulous surgery are imperative when treating the surface of the diaphragm. This procedure should only be performed by an experienced laparoscopic surgeon after appropriate consultation with a cardiothoracic surgeon. Proper care, a thorough understanding of surrounding anatomic structures, and familiarity with laparoscopic instrumentation including the CO2 laser are required for the safe laser vaporization or excision of any peritoneal surface using hydrodissection (7).

Enamel silicon and fluoride relationships demonstrating a surface silicon effect that facilitates fluoride uptake.

This study indicated that a clear relationship exists between silicon and fluoride. We have also demonstrated a probable surface enamel silicon effect that increases fluoride uptake. The complex set of relationships described in the surface chemistry of calcium, tin, and zirconium with fluoride, hydroxide, phosphate, and other surface-occurring ions need not be considered to confuse the specific silicon-fluoride relationship presented here because in this computation we are relating the changes in the silicon and fluoride ion values only. We have, however, considered the thermodynamics of such reactions and intend to elaborate on it in a later publication. We are aware of the small depth of fluoride penetration into enamel after topical treatment Health Foundation, Research Unit at the National Bureau of Standards, Washington, DC 20034, USA.

Therapeutic and diagnostic implications of acquired choledochal obstruction in infancy: spontaneous resolution in three infants.

Three infants aged 2 days to 11 weeks with conjugated hyperbilirubinenemia, had sonographically documented dilated common hepatic bile ducts, and echogenic material in the gallbladder. A 2-day-old infant, born to a diabetic mother, had none of the classic predisposing factors for cholelithiasis, and two infants had received total parenteral nutrition (TPN) and TPN plus furosemide. The first infant after receiving 4 1/2 weeks of TPN and furosemide, developed common duct obstruction with increasing bilirubin and hepatic duct caliber over a 12-day period. An operation was scheduled; however, on the following day the bilirubin dropped abruptly and surgery was canceled. The experience with this infant encouraged conservative management in two subsequent infants with similar clinical and sonographic findings. Spontaneous resolution occurred 9 days after the onset of common duct obstruction in one infant and after 16 days in the other.

Comparison of the nipple stimulation and exogenous oxytocin contraction stress tests. A randomized, prospective study.

In a prospective, randomized trial, 103 women underwent a total of 203 antenatal stress tests. One hundred four nipple stimulation contraction stress tests (BSTs) and 99 oxytocin challenge tests (OCTs) were performed. The patient populations were similar for the two groups. Uterine hyperstimulation with abnormal fetal heart rate patterns occurred with 2.9% and 1% of the BSTs and OCTs, respectively. The failure rate for the BST group was 22%. Maternal age and weight, parity and gestational age were not associated with test failure. Only one patient failed more than one BST, but she did not fail every such test. When test time (time from initiation to completion of the test) was compared between the two groups, a significant difference was found when the BST was successful. However, when test time in the total BST group (successful and unsuccessful BSTs followed by an OCT was compared to that in the OCT group, no difference could be found. Though an OCT following an unsuccessful BST took longer to perform than did a primary OCT, the difference was not statistically significant. It appears that BST test failure may relate more to the technique of nipple stimulation used than to intrinsic patient factors.

Use of hysteroscopy in addition to laparoscopy for evaluating chronic pelvic pain.

This study assessed whether hysteroscopy can provide information concerning the cause of chronic pelvic pain. We prospectively evaluated the findings in 547 consecutive patients who had laparoscopy to evaluate chronic pelvic pain at a large, referral-based clinic and outpatient suite of a suburban hospital. Forty-eight had previous hysterectomies. The remaining 499 had hysteroscopy during the same surgery and met the following qualifications: chronic pelvic pain, dysmenorrhea, dyspareunia, dysuria, back pain, pelvic pressure or dyschezia for a duration greater than six months and previous failed medical therapy. When endometriosis was the primary diagnosis at laparoscopy, hysteroscopy revealed abnormalities in 62 (32.5%) of 191 patients. At hysteroscopy, 46 of 105 patients (43.8%) with single or multiple leiomyomas of significant sizes diagnosed laparoscopically were noted to have pathology within the uterine cavity. Ten of 11 patients (90.9%) found to have ovarian cysts underwent hysteroscopy. Four (40%) had uterine abnormalities; the most common was cervical stenosis. Pelvic adhesions were found in 118 patients (21.6%). Eighty-nine underwent hysteroscopy, and 24 (27%) had intrauterine abnormalities. Ninety-six patients (17.5%) who underwent laparoscopic evaluation had endometriosis and pelvic adhesions. Ninety-three of these underwent hysteroscopy, and abnormalities were noted in 26 (28.0%). In eight women (1.5%) no abnormality was found at laparoscopy. Two underwent hysteroscopy, and no abnormality was noted in either woman. Hysteroscopy provides useful, adjunctive information and may improve the diagnosis and treatment of chronic pelvic pain.

Marketing service guarantees for health care.

The author introduces the concept of service guarantees for application in health care and differentiates between explicit, implicit, and conditional vs. unconditional types of guarantees. An example of an unconditional guarantee of satisfaction is provided by the hospitality industry. Firms conveying an implicit guarantee are those with outstanding reputations for products such as luxury automobiles, or ultimate customer service, like Nordstrom. Federal Express and Domino's Pizza offer explicit guarantees of on-time delivery. Taking this concept into efforts to improve health care delivery involves a number of caveats. Customers invited to use exceptional service cards may use these to record either satisfaction or dissatisfaction. The cards need to provide enough specific information about issues so that "immediate action could be taken to improve processes." Front-line employees should be empowered to respond to complaints in a meaningful way to resolve the problem before the client leaves the premises.

Down's syndrome and the gastrointestinal tract.

Gastrointestinal (GI) abnormalities are frequent in patients with Down's syndrome. In a 12-year retrospective review, we identified 187 patients with Down's syndrome admitted to the Columbia-Presbyterian Medical Center. Twenty-seven had major GI disorders, the most common being duodenal stenosis (DS, nine), gastroesophageal reflux (GER, five), imperforate anus (five), and Hirschsprung's disease (four). The mortality for the whole group was 11% (20 patients). The mortality in the small group of patients with duodenal stenosis was particularly high (five out of nine, or 56%). Associated congenital heart disease, especially endocardial cushion defects, and the frequent occurrence of pneumonia contributed to this high mortality rate.

Relation of chronic and episodic stressors to psychological distress, reactivity, and health.

This study tested the hypothesis that exposure to chronic stressors, which reflect persistent, negative life situations, would have greater physiological, psychological, and physical health costs than exposure to episodic or intermediate-length stressors, which reflect relatively transient, negative life situations. We also tested whether cardiovascular reactivity, conceptualized as a marker of underlying pathophysiological states, would mediate the relation between chronic stress and psychological distress and illness. Participants were 75 male and 75 female college students. Compared with students experiencing few chronic life stressors, students experiencing many chronic life stressors had exaggerated cardiovascular responses to acute challenges, delayed recovery to resting levels of cardiovascular functioning after the acute challenges, elevated psychological distress levels, and they reported more illnesses. None of the outcomes was associated with the number of episodic or intermediate-length life stressors students experienced. Cardiovascular reactivity did not mediate the stress-distress or stress-illness associations. The results suggest that ongoing stressors that are static are more detrimental to health and well-being than are episodic of change-related stressors.

Negative interactions between amino acid and methylamine/ammonia transport systems of Saccharomyces cerevisiae.

The transport of methylamine (methylammonium ion) and ammonia (ammonium ion) is accomplished in Saccharomyces cerevisiae by means of a specific active transport system. L-Amino acids are noncompetitive inhibitors of methylamine transport. This inhibition is relieved or eliminated in mutant strains that have a reduced ability to transport amino acids. The inhibition of methylamine transport occurs immediately upon the addition of amino acids to the assay system and persists until the external amino acid pool is depleted. The degree of inhibition observed is a direct function of the rate of amino acid transport. Both methylamine and ammonia are capable of inhibiting amino acid transport. The inhibition of amino acid transport is eliminated in mutant strains that cannot transport methylamine and ammonia.

Inhibition of amino acid transport by ammonium ion in Saccharomyces cerevisiae.

The rate of transport of L-amino acids by Saccharomyces cerevisiae epsilon 1278b increased with time in response to nitrogen starvation. This increase could be prevented by the addition of ammonium sulfate or cycloheximide. A slow time-dependent loss of transport activity was observed when ammonium sulfate (or ammonium sulfate plus cycloheximide) was added to cells after 3 h of nitrogen starvation. This loss of activity was not observed in the presence of cycloheximide alone. In a mutant yeast strain which lacks the nicotinamide adenine dinucleotide phosphate-dependent (anabolic) glutamate dehydrogenase, no significant decrease in amino acid transport was observed when ammonium sulfate was added to nitrogen-starved cells. A double mutant, which lacks the nicotinamide adenine dinucleotide phosphate-dependent enzyme and in addition has a depressed level of the nicotinamide adenine dinucleotide-dependent (catabolic) glutamate dehydrogenase, shows the same sensitivity to ammonium ion as the wild-type strain. These data suggest that the inhibition of amino acid transport by ammonium ion results from the uptake of this metabolite into the cell and its subsequent incorporation into the alpha-amino groups of glutamate and other amino acids.

Acute pulmonary edema complicating diagnostic laparoscopy preceded by thoracotomy.

We report the case of a patient with pelvic endometriosis and recurrent spontaneous pneumothoraces who had thoracotomy and diagnostic laparoscopy, with subsequent acute pulmonary edema. Potential causes are discussed. After a thorough literature search, we believe this to be the first case in which thoracotomy has been combined with diagnostic laparoscopy.

St. Louis encephalitis in Memphis-Shelby County, Tennessee, 1975: epidemiologic aspects of human cases.

An epidemic of St. Louis encephalitis (SLE) occurred in Memphis-Shelby County, Tennessee, in the summer of 1975, as part of an outbreak involving large portions of the Eastern United States. A total of 187 suspected cases were reported, of which 62 were laboratory-confirmed or presumptive SLE. The overall attack rate was 8.1/100,000; rates were higher in lower socioeconomic districts. The case fatality rate was 19.4%. Climatologic data and related factors favoring the occurrence of this outbreak are discussed.