Two-dimensional plasmonic grating for increased quantum efficiency in midwave infrared nBn detectors with thin absorbers.

We demonstrate a strategy for increasing the operating temperatures of nBn midwave infrared (MWIR) focal plane arrays, based on the use of two-dimensional plasmonic gratings to enhance the quantum efficiency (QE) of structures with very thin absorbers. Reducing the absorber volume correspondingly reduces the dark current in a diffusion-limited photodiode, while light trapping mediated by the plasmonic grating increases the net absorbance to maintain high QE. The plasmonically enhanced nBn MWIR sensors with absorber thicknesses of only 0.5 µm exhibit peak internal QEs as high as 57%, which enables a 5-fold reduction in dark current. Numerical simulations indicate the potential for further improvement.

The role of losses in determining hyperbolic material figures of merit.

Uniaxial materials have achieved new prominence in photonics because they can have hyperbolic spectral regions with metallic (ε<0) and dielectric (ε>0) permittivities along different crystal axes. In the lossless case, this results in an open hyperboloid dispersion relation, allowing materials to support highly confined modes with extremely large wavevectors. However, even small losses change the character of the hyperbolic dispersion from open hyperboloids to closed surfaces with finite maximum k, significantly limiting the extent to which highly-confined modes can be achieved. Here, we derive a simple analytic formula for the dispersion relation in the presence of loss and show that for some typical materials the maximum wavevector in hyperbolic materials is roughly ten times the free-space. The scaling of the maximum wavevector is derived, and it is shown that there is a universal scaling relation between the propagation length and the wavelength, which implies that the shortest wavelengths in any hyperbolic material are strongly attenuated.

Formalehyde in personal care products.

Personal care products reported to cause allergic contact dermatitis from the presence of formaldehyde need to be re-examined in light of recent chemical developments in our understanding of the film former, toluene sulfonamide formaldehyde resin, the preservatives diazolidinyl urea and imidazolidinyl urea, and formalin. This paper will elucidate these chemistries as well as review how formaldehyde is used in personal care products in raw materials and formaldehyde donor preservatives.

Subungual penetration of dibutyl phthalate in human fingernails.

Dibutyl phthalate (DBP) has a wide variety of manufacturing applications and is used in both commercial and consumer products. Results of animal reproductive toxicity and teratogenicity animal studies have not been consistent in identifying DBP as a reproductive toxicant. Expert reviews for its use in consumer products have consistently concluded that it is not a reproductive risk to consumers. Results from a subungual penetration study of 100% fluid DBP applied to human fingernails showed levels of penetration at the limits of chemical detection. Even if DBP penetrated the human fingernail, its rapid metabolism by the human body would prevent its having any toxic reproductive effects. Furthermore, DBP functions as a plasticizer in consumer products such as cosmetic nail products (nail polish, basecoats, topcoats, nail hardeners), resulting in its becoming unavailable for subungual penetration seconds after application of the cosmetic nail product since it is then trapped in the rapidly forming coating.

Ultrafast Brain MRI Can Be Used for Indications beyond Shunted Hydrocephalus in Pediatric Patients.

BACKGROUND AND PURPOSE: Evaluation of shunted hydrocephalus is the most common indication for ultrafast brain MRI. Radiation-/sedation-free imaging capabilities make this protocol more desirable over CT and standard brain MRI. We hypothesized that ultrafast brain MRI can be used for selected indications beyond shunted hydrocephalus without adverse outcomes. MATERIALS AND METHODS: Ultrafast brain MRI was performed with axial, sagittal, and coronal HASTE. The radiology information system was used to identify pediatric patients (0-18 years of age) who underwent ultrafast brain MRI between March 2014 and May 2016. A retrospective chart review was completed to identify indications other than shunted hydrocephalus, such as ventriculomegaly, macrocephaly, or intracranial cyst. All ultrafast brain MRIs were evaluated by a certified neuroradiologist and a neurosurgeon. Ultrafast brain MRI was deemed of sufficient diagnostic value for these indications if no further standard brain MRI was required for the study indication or if additional imaging was performed for an alternate indication. RESULTS: The radiology information system identified 800 patients who had undergone an ultrafast brain MRI during the study period. One hundred twenty-two of these patients had ventriculomegaly, macrocephaly, or intracranial cyst as the study indication. Twenty-one of the 122 patients were excluded due to insufficient follow-up. Of the remaining 101 patients, only 5 had a standard brain MRI for the same indication, with no additional clinically significant information identified on those studies. CONCLUSIONS: These results suggest that ultrafast brain MRI is sufficient to evaluate ventriculomegaly, macrocephaly, or intracranial cyst. Ultrafast brain MRI is radiation- and sedation-free; therefore, we recommend its use as the primary screening neuroimaging study for these indications.

How to Reduce Head CT Orders in Children with Hydrocephalus Using the Lean Six Sigma Methodology: Experience at a Major Quaternary Care Academic Children's Center.

BACKGROUND AND PURPOSE: Lean Six Sigma methodology is increasingly used to drive improvement in patient safety, quality of care, and cost-effectiveness throughout the US health care delivery system. To demonstrate our value as specialists, radiologists can combine lean methodologies along with imaging expertise to optimize imaging elements-of-care pathways. In this article, we describe a Lean Six Sigma project with the goal of reducing the relative use of pediatric head CTs in our population of patients with hydrocephalus by 50% within 6 months. MATERIALS AND METHODS: We applied a Lean Six Sigma methodology using a multidisciplinary team at a quaternary care academic children's center. The existing baseline imaging practice for hydrocephalus was outlined in a Kaizen session, and potential interventions were discussed. An improved radiation-free workflow with ultrafast MR imaging was created. Baseline data were collected for 3 months by using the departmental radiology information system. Data collection continued postintervention and during the control phase (each for 3 months). The percentage of neuroimaging per technique (head CT, head ultrasound, ultrafast brain MR imaging, and routine brain MR imaging) was recorded during each phase. RESULTS: The improved workflow resulted in a 75% relative reduction in the percentage of hydrocephalus imaging performed by CT between the pre- and postintervention/control phases (Z-test, P = .0001). CONCLUSIONS: Our lean interventions in the pediatric hydrocephalus care pathway resulted in a significant reduction in head CT orders and increased use of ultrafast brain MR imaging.

Effects of dietary cholesterol and fat, sex and sire on lecithin-cholesterol acyltransferase activity in baboons.

We analyzed the effects of dietary cholesterol, type of dietary fat, sex and sire progeny family on lecithin-cholesterol acyltransferase activity in 80 adult baboons. The animals were the progeny of 80 dams and 6 sires and were randomly assigned at birth to breast feeding or to one of three formulas containing 0.02, 0.30 or 0.60 mg cholesterol/ml. After weaning at 4 months of age the animals were fed one of four diets that were either high or low in cholesterol with 40% of the calories from either saturated or unsaturated fat. The fractional and molar rates of lecithin-cholesterol acyltransferase activity were measured at 7-8 years of age by an HPLC method. Infant diet (breast vs. formula feeding or level of cholesterol in formula had no effect on enzyme activity later in life. The adult diets that were high in cholesterol decreased the fractional lecithin-cholesterol acyltransferase rate by 20% / compared to diets low in cholesterol (7.89 vs. 9.84%/h, P less than 0.002), but dietary cholesterol did not affect the molar activity. Animals fed the high cholesterol diets had higher unesterified cholesterol concentrations compared to those fed the low cholesterol diets (38.1 mg/dl vs. 31.6 mg/dl, P less than 0.0001). The molar lecithin-cholesterol acyltransferase rate was increased 13% by saturated compared to unsaturated fat (83.3 vs. 73.6 nmol/h per ml plasma, P less than 0.07), but no effect of dietary fat was observed on the fractional enzyme activity. Females compared to males had significantly higher fractional (10.9 vs. 7.14%/h, P less than 0.0001) and molar lecithin-cholesterol acyltransferase activities (99.3 vs. 61.7 nmol/h per ml plasma, P less than 0.0001). After adjustment for the effects of diet and sex we observed differences in the fractional activity (range, 7.2-10.8%/h, P less than 0.04) and in the molar rate (range, 63.6-99.8 nmol/h per ml plasma, P less than 0.07) among the six sire progeny groups. The differences among sire progeny groups are evidence for genetic differences in lecithin-cholesterol acyltransferase activities among the baboon families.

Kinetics and plasma concentrations of 26-hydroxycholesterol in baboons.

26-Hydroxycholesterol (26OHC), a major oxysterol in human blood, is believed to play an important role in reverse cholesterol transport, bile acid formation, and regulation of various cellular processes. Using isotope dilution mass spectrometry, we measured plasma 26OHC concentrations in baboons fed either a high cholesterol/saturated fat (HC-SF) or normal chow diet. Plasma 26OHC levels in baboons were comparable to those reported for humans and were positively correlated with plasma cholesterol concentrations. Animals on the HC-SF diet had significantly higher 26OHC levels (0.274+/-0.058 microM, mean+/-S.D.) than those on the chow diet (0.156+/-0.046 microM). In separate experiments, [(3)H]26OHC was injected into four tethered baboons, and multiple blood samples drawn over a 1-h period were analyzed for [(3)H]26OHC and 26OHC. Fitting the specific radioactivity data to a two-pool compartmental model indicated a rapidly turning over plasma compartment (t(1/2) 2.9-6.0 min) and a second compartment with slow turnover (t(1/2) 76-333 min). The calculated 26OHC production rate was 2.5 micromol/kg body weight/day. Assuming all 26OHC is converted to bile acids, the 26OHC production rate corresponds to about 10% of total bile acid production in adult baboons. These results indicate that rapid turnover of plasma 26OHC at submicromolar concentrations could significantly contribute to bile acid synthesis.

Effect of energy intake on postprandial plasma hormones and triglyceride concentrations in infant female baboons (Papio species).

We previously reported that female baboons overfed during infancy were not fatter at weaning, but developed hypertrophic obesity after puberty. To clarify the mechanisms of this dietary effect on adipocyte hypertrophy, we determined the effects of infant overfeeding on preweaning plasma hormone and triglyceride levels and their relationship with fat cell volume at weaning (19 weeks of age). Newborn female baboons from 3 sires and 24 dams were fed either 280 kilojoules (normally fed; n = 12) or 395 kilojoules (overfed; n = 10) per 100 g Similac formula for 18 weeks. Both formulas contained 9.2%, 43.1%, and 48.5% of calories as protein, carbohydrate, and fat, respectively. During the first 9 weeks, overfed infants had significantly higher fasting and postprandial insulin, total T3, and free T3 concentrations; lower cortisol levels; and lower excretion of urinary 17-hydroxycorticosteroids (17-OHCS) than normally fed infants. These effects were no longer significant at 17-18 weeks. Infant diet did not influence fasting and postprandial plasma triglyceride levels, and fat cell volume was not influenced by energy intake. However, fat cell volume was positively associated with postprandial triglyceride concentrations and inversely associated with postmeal nadir cortisol levels. These results demonstrate that infant overfeeding initiates early alterations in insulin, T3, free T3, and cortisol, but these effects persist only as long as there is a significant increase in energy intake.

Effects of dietary cholesterol, type of fat, and sex on bile lipid composition of adult baboons.

We measured the effects of dietary cholesterol (0.24 vs 0.0024 mg/kJ), type of dietary fat [saturated, a ratio of polyunsaturated to saturated fatty acids (P:S) of 0.37, vs unsaturated (P:S of 2.2)], and sex on biliary lipid and bile acid conjugate composition of 80 adult pedigreed baboons. From these data we calculated the bile cholesterol saturation index and the bile acid hydrophobicity index. Dietary cholesterol significantly increased the bile cholesterol concentration by 25% and the bile cholesterol saturation index by 15%, but did not significantly affect the bile acid conjugate composition or the bile acid hydrophobicity index. Diets high in saturated fatty acid compared with unsaturated fatty acid significantly decreased the bile cholesterol concentrations by 26% and the saturation index by 23%. Saturated fatty acid also decreased the proportion of hydrophobic bile acids and lowered the bile hydrophobicity index. Male baboons had a higher cholesterol saturation index and a lower hydrophobicity index than females. Dietary cholesterol and saturated fatty acid independently influence the bile lipid composition and the cholesterol saturation index.

Safety and efficacy of a topical anesthetic for neonatal circumcision.

OBJECTIVE: Circumcision is a common neonatal surgical procedure routinely performed without the use of anesthesia. The purpose of this study was to evaluate the safety and efficacy of topical lidocaine cream as an anesthetic for circumcision. METHODS: Thirty newborns were studied in a randomized, double-blind, placebo-controlled study; 15 received a topical 30% lidocaine cream and 15 received the cream base alone. Vital signs were recorded, and preoperative and postoperative serum beta-endorphin and lidocaine concentrations were measured. A videotape of the newborn was used to score behavioral changes. RESULTS: Comparisons of the vital signs precircumcision and postcircumcision showed no differences between the placebo and treatment groups, with the exception of mean systolic blood pressure, which significantly increased in the placebo-treated newborns (P < .05). Serum beta-endorphin concentrations increased postoperatively in 11 of 15 subjects receiving placebo, but decreased or remained unchanged in 10 of 15 subjects receiving lidocaine (P = .03, Fisher's exact test). When stress-related behaviors in the precircumcision and post-circumcision periods were compared, the mean increase in their occurrence was greater in the placebo than in the treatment group. There was no significant absorption of lidocaine as measured in the serum. CONCLUSION: Topical application of a 30% lidocaine cream as used in this study may be a safe and efficacious anesthetic for circumcision.

Early determinants of adult metabolic regulation: effects of infant nutrition on adult lipid and lipoprotein metabolism.

In a series of experiments over the past 20 years, we have demonstrated long-term deferred effects of infant nutrition, particularly breast- as compared with formula-feeding and overfeeding as compared with normal or underfeeding, on serum HDL-cholesterol concentrations, adiposity, and atherosclerosis in the baboon, a large nonhuman primate. Low HDL-cholesterol levels and obesity are associated with accelerated progression of atherosclerosis and with increased risk of coronary heart disease in humans. We have observed other deferred effects of infant nutrition on bile acid metabolism, enzyme activities, and water and electrolyte balance, some of which may be physiologically related to HDL-cholesterol levels or to adiposity. The occurrence of these deferred effects suggests that infant nutrition may program other metabolic systems for life, and that these effects may contribute to other chronic diseases of adults. Although our understanding of the mechanisms by which infant diet regimens affect adult metabolism is meager, it is important to identify these mechanisms because they are likely to provide valuable clues to the causes and ultimately may contribute to the long-range prevention of those diseases.

Inhibitors of sterol synthesis. Metabolism of [2,4-3H]5 alpha-cholest-8(14)-en-3 beta-ol-15-one after oral administration to a nonhuman primate.

5 alpha-Cholest-8(14)-en-3 beta-ol-15-one is a potent inhibitor of cholesterol biosynthesis which has significant hypocholesterolemic activity upon oral administration to rodents and nonhuman primates. In the present study the metabolism of the 15-ketosterol has been investigated after the oral administration of a mixture of [2,4-3H]5 alpha-cholest-8(14)-en-3 beta-ol-15-one and [4-14C]cholesterol to 8 baboons. Blood samples were obtained at 4, 8, 12, 16, and 24 h after administration of the labeled sterols. Clear differences in the time courses of the levels of 3H and 14C in plasma were observed. 3H in plasma showed maximum values at 4 to 8 h, whereas maximum values for the levels of 14C were observed much later. 3H in plasma was shown to be primarily in the form of its metabolites, i.e. esters of the 15-ketosterol, cholesterol, and cholesteryl esters. The levels of the 15-ketosterol and of each of these metabolites showed different changes with time. The labeled cholesterol (and the cholesterol moiety of the cholesteryl esters), formed from the [2,4-3H]-15-ketosterol, was characterized by chromatography and by purification by way of its dibromide derivative. At 24 h after the administration of the labeled sterols, the distribution of 3H in plasma lipoprotein fractions paralleled that of 14C, with most of the 3H and 14C in high density lipoprotiens (HDL) and low density lipoproteins (LDL). Almost all of the 3H in HDL and in LDL was found as cholesterol, cholesteryl esters and esters of the 15-ketosterol. The distribution of 3H in HDL and in LDL of the free 15-ketosterol, esters of the 15-ketosterol, cholesterol, and cholesteryl esters was similar to that of plasma, thereby indicating no unusual concentration of any of the 3H labeled components in HDL or LDL.

Inadequate standard for glove puncture resistance: allows production of gloves with limited puncture resistance.

The National Fire Protection Association has developed standards for glove puncture resistance using a metal puncture probe. Biomechanical performance studies have demonstrated that glove puncture resistance to the probe is significantly greater than that of the hypodermic needle, suggesting that these standards have no clinical relevance. These standards give a false sense of security to health care personnel and sanction the production and use of gloves that give inadequate protection. The result is potentially harmful for medical personnel.

A global inventory of hospitals using powder-free gloves: a search for principled medical leadership.

Scientific experimental and clinical studies have demonstrated that cornstarch on surgical and examination gloves promotes disease by acting as a reactive foreign body in tissue and serving as a vector for latex allergy. Consequently, hospitals have selected an innovative glove selection program utilizing only powder-free gloves. Healthcare workers in emergency medical systems are now wearing powder-free, latex-free gloves to care for the growing number of patients sensitized to latex. A global Internet search has now identified 70 hospitals in the United States and three hospitals in Europe that use only powder-free gloves.

Latex glove penetration by pathogens: a review of the literature.

Universal precautions mandate the use of examination and surgical gloves to protect the health professional from contact with the HIV virus. The purpose of this paper is to provide a review of the literature on the barrier properties of examination and surgical gloves measured by water leakage and viral penetration. The literature data indicate that glove composition, glove manufacturer, glove design (examination vs. surgical), and mechanical manipulation had considerable influence on glove performance when tested for leakage and viral penetration. In general, latex gloves were found to be superior to vinyl gloves as barriers to water leakage and viral penetration.

Influence of latex glove hydration on bacteriophage penetration.

The purpose of this study was to determine whether glove hydration influenced bacteriophage penetration. Using an electronic glove hole-detection device, one brand of latex glove was identified that hydrated rapidly (3.25 min +/- 0.71 min), while another brand was selected that resisted hydration (120 min +/- 0 min). Using a standard bacteriophage penetration model, the amount of bacteriophage penetration in both the rapidly hydrating gloves and the gloves that resisted hydration was extremely small and did not differ significantly from each other.

Dimensions of care in five United States nursing homes: identifying invisible work in care-giving.

This article reports on a study carried out to identify components of practical knowledge, which is the knowledge that is used to guide decision-making and actions, used by care-givers in nursing homes. The practical knowledge behind the giving of care in the day-to-day activities in five nursing homes was studied and models for such care were developed. One finding from this study was that a large portion of the work of caring as known and understood by care-participants (patients, families, and nursing staff) was excluded from prescribed routines established by administration for care.

Facial moisturizers and wrinkles.

Facial moisturizers are part of the cosmetic category known as skin care products, which also includes other facial products such as astringents, toners, soaps, and bath products. This article describes the composition and pharmaceutics of currently marketed moisturizers, the use of fragrances and preservatives in these products, how cosmetic facial moisturizers work on wrinkles, sunscreen-containing facial moisturizers, and the Food and Drug Administration's record regulating drug claims for anti-wrinkling products.

Prognostic patch testing: the other kind of patch test.

Prognostic patch testing differs from diagnostic patch testing. Clinicians routinely perform diagnostic patch testing, but prognotic patch testing is the province of corporate research and development departments and, in the United States, contract laboratories. The three types of prognostic patch testing are described and referenced in the scientific and medical literature. A comparison among the three types of prognostic patch testing and diagnostic patch testing is provided. In addition, the variables in both prognostic and diagnostic patch testing are listed, as well as the types of ingredients and products routinely tested in prognostic patch testing.