Fragility of surface states in topological superfluid 3He.

Superfluid 3He, with unconventional spin-triplet p-wave pairing, provides a model system for topological superconductors, which have attracted significant interest through potential applications in topologically protected quantum computing. In topological insulators and quantum Hall systems, the surface/edge states, arising from bulk-surface correspondence and the momentum space topology of the band structure, are robust. Here we demonstrate that in topological superfluids and superconductors the surface Andreev bound states, which depend on the momentum space topology of the emergent order parameter, are fragile with respect to the details of surface scattering. We confine superfluid 3He within a cavity of height D comparable to the Cooper pair diameter ξ0. We precisely determine the superfluid transition temperature Tc and the suppression of the superfluid energy gap, for different scattering conditions tuned in situ, and compare to the predictions of quasiclassical theory. We discover that surface magnetic scattering leads to unexpectedly large suppression of Tc, corresponding to an increased density of low energy bound states.

Reduction of cicatricial stenosis after canalplasty for auditory exostoses.

BACKGROUND: Canalplasty for auditory exostoses is reserved for symptomatic patients. This study reviewed the outcomes of our technique regarding cicatricial stenosis. METHOD: A chart review was conducted on patients undergoing canalplasty for auditory exostoses between 2002 and 2017. The surgical technique is described. RESULTS: The study comprised 43 adults (50 operated ears). Exostoses were bilateral in 40 cases (94 per cent) and occlusive in 33 (66 per cent). After drilling, the external auditory meatus was covered with a graft in 34 cases (68 per cent) and a silicone sheet was used in 32 (64 per cent). Cicatricial stenosis appeared in eight cases (16 per cent). Skin grafts were not used in six of these eight cases (p < 0.04), and silicone sheets were used only in one of these eight (p < 0.01). CONCLUSION: Canalplasty is challenging because of its potential complications. Our data showed that the use of skin grafts and silicone sheets to cover the bared external auditory meatus was associated with a lower rate of cicatricial stenosis.

Fabrication of microfluidic cavities using Si-to-glass anodic bonding.

We demonstrate the fabrication of ∼1.08 µm deep microfluidic cavities with characteristic size as large as 7 mm × 11 mm or 11 mm diameter, using a silicon-glass anodic bonding technique that does not require posts to act as separators to define cavity height. Since the phase diagram of 3He is significantly altered under confinement, posts might act as pinning centers for phase boundaries. The previous generation of cavities relied on full wafer-bonding which is more prone to failure and requires dicing post-bonding, whereas these cavities are made by bonding a pre-cut piece of Hoya SD-2 glass to a patterned piece of silicon in which the cavity is defined by etching. Anodic bonding was carried out at 425 °C with 200 V, and we observe that pressurizing the cavity to failure (>30 bars pressure) results in glass breaking, rather than the glass-silicon bond separation. In this article, we discuss the detailed fabrication of the cavity, its edges, and details of the junction between the coin silver fill line and the silicon base of the cavity that enables a low internal-friction joint. This feature is important for mass coupling torsional oscillator experimental assays of the superfluid inertial contribution where a high quality factor (Q) improves frequency resolution. The surface preparation that yields well-characterized smooth surfaces to eliminate pinning sites, the use of transparent glass as a cover permitting optical access, low temperature capability, and attachment of pressure-capable ports for fluid access may be features that are important in other applications.

The A-B transition in superfluid helium-3 under confinement in a thin slab geometry.

The influence of confinement on the phases of superfluid helium-3 is studied using the torsional pendulum method. We focus on the transition between the A and B phases, where the A phase is stabilized by confinement and a spatially modulated stripe phase is predicted at the A-B phase boundary. Here we discuss results from superfluid helium-3 contained in a single 1.08-µm-thick nanofluidic cavity incorporated into a high-precision torsion pendulum, and map the phase diagram between 0.1 and 5.6 bar. We observe only small supercooling of the A phase, in comparison to bulk or when confined in aerogel, with evidence for a non-monotonic pressure dependence. This suggests that an intrinsic B-phase nucleation mechanism operates under confinement. Both the phase diagram and the relative superfluid fraction of the A and B phases, show that strong coupling is present at all pressures, with implications for the stability of the stripe phase.

Occupational asthma and urticaria in a fishmonger due to creatine kinase, a cross-reactive fish allergen

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Optical microscope and tapered fiber coupling apparatus for a dilution refrigerator.

We have developed a system for tapered fiber measurements of optomechanical resonators inside a dilution refrigerator, which is compatible with both on- and off-chip devices. Our apparatus features full three-dimensional control of the taper-resonator coupling conditions enabling critical coupling, with an overall fiber transmission efficiency of up to 70%. Notably, our design incorporates an optical microscope system consisting of a coherent bundle of 37,000 optical fibers for real-time imaging of the experiment at a resolution of ∼1 µm. We present cryogenic optical and optomechanical measurements of resonators coupled to tapered fibers at temperatures as low as 9 mK.

Remote sensing in hybridized arrays of nanostrings.

We study high-Q nanostrings that are joined end-to-end to form coupled linear arrays. Whereas isolated individual resonators exhibit sinusoidal vibrational modes with an almost perfectly harmonic spectrum, the modes of the interacting strings are substantially hybridized. Even far-separated strings can show significantly correlated displacement. This remote coupling property is exploited to quantify the deposition of femtogram-scale masses with string-by-string positional discrimination based on measurements of one string only.

Birth weight and obesity risk at first grade in a cohort of Chilean children.

The purpose of the study was to determine the association of birth weight as a risk factor for obesity at first grade in a cohort of elementary school Chilean children. Height and weight at birth and follow up measurements at first grade were analyzed from a national cohort of 119,070 new borns. Subjects were classified by anthropometric characteristics: new born weight in kilograms, Ponderal Index, (birth weight/height³ x 100), and gestational age (physical maturity) categories at birth. The study tested the hypothesis that a macrocosomic newborn (≥ 4,000 g or > 8.8 pounds) or Large for Gestational Age, would be at higher risk to be obese at first grade. A positive relationship between birth weight ≥ 4,000 g, (O.R. =1.55), (p < 0.001), high Ponderal Index (O.R. = 1.39), (p < 0.001), large for gestational age (O.R. = 1.51), (p < 0.001), and obesity at first grade was found. Macrosomic children were more likely to be obese at first grade after controlling for the effects of confounding prenatal variables (O.R. = 1.67, (p < 0.001). When weight gain between birth and first grade was ≥ 120% of reference value, the obesity risk was 20 times higher (p < 0.001). A direct and statistically significant relationship between high birth weight and obesity at first grade in this group of Chilean children were observed. These results highlight the significance of birth weight as an important tool for healthcare providers that can be used as an indicator of obesity risk for children.

Birth weight and obesity risk at first grade in a cohort of Chilean children / Peso al nacer y riesgo de obesidad en primer grado en una cohorte de niños chilenos

The purpose of the study was to determine the association of birth weight as a risk factor for obesity at first grade in a cohort of elementary school Chilean children. Height and weight at birth and follow up measurements at first grade were analyzed from a national cohort of 119,070 new borns. Subjects were classified by anthropometric characteristics: new born weight in kilograms, Ponderal Index, (birth weight/height3 x 100), and gestational age (physical maturity) categories at birth. The study tested the hypothesis that a macrocosomic newborn (> 4,000 g or > 8.8 pounds) or Large for Gestational Age , would be at higher risk to be obese at first grade. A positive relationship between birth weight > 4,000 g, (O.R. =1.55), (p < 0.001), high Ponderal Index (O.R. = 1.39), (p < 0.001), large for gestational age (O.R. = 1.51), (p < 0.001), and obesity at first grade was found. Macrosomic children were more likely to be obese at first grade after controlling for the effects of confounding prenatal variables (O.R. = 1.67, (p < 0.001). When weight gain between birth and first grade was > 120% of reference value, the obesity risk was 20 times higher (p < 0.001). A direct and statistically significant relationship between high birth weight and obesity at first grade in this group of Chilean children were observed. These results highlight the significance of birth weight as an important tool for healthcare providers that can be used as an indicator of obesity risk for children (AU)

Objetivo: determinar la asociación entre el peso al nacer y el riesgo de obesidad en escolares de primer año de enseñanza Metodología: se analizó el peso y talla al nacer y las mismas variables al ingresar a la escuela en una cohorte de 119.070 recién nacidos chilenos. El peso al nacer fue categorizado: en Kg (< 2.500 g, >; 4.000 g), según edad gestacional (pequeño, adecuado y grande) y según el índice ponderal (peso al nacer g/ talla al nacer cm3) * 100: bajo < 2,49 normal, 2,50 to 3,16 y alto > 3,17. El estado nutricional en los escolares fue clasificado según IMC (peso/talla2) de acuerdo a la referencia del CDC. Se consideró obesidad un valor > percentilo 95. Resultados: Un incremento de peso entre el nacimiento y el ingreso a la escuela > 120% de la referencia determinó un alto riesgo de obesidad: OR 20,5 95% IC 19,7-21,4. Se observó también una relación directa y estadísticamente significativa entre un peso al nacer > 4.000 g (OR 1,55 95% IC 1,48-1,61), grande para la edad gestacional (OR 1,51 95% IC 1,45-1,57) y alto índice ponderal (OR 1,39 95% IC 1,31-1,47) con la obesidad en primer grado, controlando el efecto de variables perinatales de confusión (p < 0,001). El bajo peso al nacer fue un factor protector de la obesidad futura (OR 0,75 IC 0,69-0,81 p < 0,001). Conclusiones: existe una relación directa entre un alto peso al nacer y el riesgo de obesidad en edad escolar. El peso al nacer puede ser una valiosa herramienta para el equipo de salud para identificar niños con mayor probabilidad de desarrollar obesidad y actuar preventivamente (AU)

Novel, continuous visual motion induces c-fos expression in the avian optokinetic nuclei and optic tectum.

We studied the stimulus characteristics necessary for the expression of c-fos protein in optokinetic system neurons using immunocytochemistry. Using whole-field visual motion as a stimulus, we found substantial c-fos expression in the optic tectum (TeO), the nucleus of the basal optic root (nBOR) and the pretectal nucleus lentiformis mesencephali (LM); in all cases immunostaining was seen only on the side contralateral to the eye viewing whole-field unidirectional motion; the side of the brain contralateral to the eye wearing a diffuser showed no staining. In the nBOR and the LM, different regions showed a remarkable specificity of c-fos expression depending on the direction of visual motion stimulation. Neurons were stained primarily in regions known from previous electrophysiological recordings to be maximally responsive to that direction of motion; little staining was seen after motion orthogonal to the preferred motion direction. Novel, continuous visual motion stimuli, lasting more than 30 min, was required for maximal c-fos expression, suggesting that brief periods of unidirectional optic flow, as would be experienced during normal life, do not stimulate the expression of c-fos. The largest number of neurons was labeled when birds raised from hatching with one eye covered by a diffuser were exposed to full-field visual motion immediately after the diffuser was switched from one eye to the other, so that only the previously naive eye was visually stimulated. We conclude that the expression of c-fos in the optokinetic nuclei is linked to near peak firing rates on the one hand, and the novelty and duration of the visual signals, on the other, supporting the assumption that this expression is mainly related to stimulus contexts leading to neuronal plastic changes.

Detection of ovine antibody to Brucella ovis by indirect enzyme immunoassay.

Because some batch-to-batch variation in the preparation of rough lipopolysaccharide (RLPS) from Brucella ovis has been experienced, several protocols were tested to establish the most reliable method for detection of antibody in indirect enzyme immunoassay. An early version of the assay gave a performance index (PI=sum of optimum percent sensitivity and percent specificity, determined by receiver operator characteristic analysis) of 198.6. This assay used RLPS from B. ovis as the antigen and a monoclonal antibody specific for bovine IgG(1) heavy chain-enzyme conjugate for detection. This was not repeatable using other batches of antigen. Newer versions of the assay generally had decreased sensitivity values, giving PIs of 193. Use of a recombinant protein A/G-enzyme conjugate did not improve the PI (PI=190), giving reduced specificity and higher sensitivity. The final version used B. abortus RB51 RLPS as the antigen and protein A/G-enzyme conjugate for detection, giving a PI of 197. Because of the batch uniformity of the B. abortus RB51 RLPS and the versatility of the protein A/G-enzyme conjugate, the latter version appears to be the most useful for diagnostic serology.

Towards single screening tests for brucellosis.

This paper describes an indirect enzyme-linked immunosorbent assay (I-ELISA) and a fluorescence polarisation assay (FPA), each capable of detecting antibody in several species of hosts to smooth and rough members of the genus Brucella. The I-ELISA uses a mixture of smooth lipopolysaccharide (SLPS) and rough lipopolysaccharide (RLPS) as the antigen, and a recombinant protein A/G conjugated with horseradish peroxidase as the detection reagent. When using individually determined cutoff values, the SLPS/RLPS combined-antigen I-ELISA detected antibody in slightly more animals exposed to SLPS or to RLPS than did I-ELISA procedures using each individual antigen separately. Similarly, the assay using combined antigens detected antibody in slightly fewer animals not exposed to Brucella sp. When a universal cutoff of 10% positivity was used (relative to strongly positive control sera of each species), the overall performance index (percentage sensitivity plus percentage specificity) value decreased by 1.0 (from 199.4 to 198.4). In the FPA, it was not possible to use a universal cutoff without significant loss of performance. The overall sensitivity value for the FPA using the combined FPA antigen was 1.0% lower than using the O-polysaccharide (OPS) from SLPS and 9.1% higher than using the core antigen (CORE) from RLPS. When the combined antigen was used, the FPA specificity was slightly higher (1.2%) than from only the OPS, and considerably higher (12.6%) than the CORE. Overall, both the I-ELISA and the FPA with combined antigens were suitable as screening tests for all species of Brucella in the animal species tested.

Enzyme immunoassay for the diagnosis of brucellosis: chimeric Protein A-Protein G as a common enzyme labeled detection reagent for sera for different animal species.

A recombinant protein combining the immunoglobulin binding sites of Proteins A and G, conjugated with horseradish peroxidase was used as a universal detection reagent for the assessment of antibodies against Brucella spp. The reagent was applied in an indirect enzyme immunoassay for detection of antibodies to smooth lipopolysaccharide antigen in sera from Brucella spp. exposed and non-exposed cattle, sheep, goats and pigs and to antibodies to rough lipopolysaccharide in sheep, dogs and cattle. The results were similar to those obtained when murine monoclonal antibody-enzyme conjugates were used. An added advantage was that a universal cut-off for all tests using the proteins A and G detection reagent could be established, simplifying diagnostic interpretation of the data.

Rough lipopolysaccharide of Brucella abortus RB51 as a common antigen for serological detection of B. ovis, B. canis, and B. abortus RB51 exposure using indirect enzyme immunoassay and fluorescence polarization assay.

Rough lipopolysaccharide (RLPS) antigens were prepared from cultures of Brucella abortus RB51, B. ovis, and B. canis. The preparations were standardized by weight and tested with sera from cattle immunized with B. abortus RB51, sheep infected with B. ovis, and dogs infected with B. canis. Populations of unexposed animals of each species were also tested. The tests used were the indirect enzyme immunoassay (IELISA) using RLPS and the fluorescence polarization assay (FPA) using RLPS core fractions, labeled with fluorescein isothiocyanate. The IELISA using B. abortus RB51 RLPS antigen resulted in sensitivity and specificity values of 94.8% and 97.3%, respectively, when testing bovine sera, 98.5% and 97.8% when testing ovine sera, and 95.8% and 100% when testing dog sera. The IELISA using B. ovis RLPS antigen gave sensitivity and specificity values of 80.5% and 91.7%, respectively with bovine sera, 98.9% and 93.8% with sheep sera, and 70.8% and 79.8% with dog sera. The IELISA using B. canis RLPS antigen resulted in sensitivity and specificity values of 97.0% and 97.4%, respectively, with bovine sera, 96.2% and 96.3% with sheep sera, and 95.8% and 98.8% with dog sera. Labeling RLPS core from B. ovis and B. canis with fluorescein was not successful. B. abortus RB51 core labeled with fluorescein resulted in sensitivity and specificity values of 93.5% and 99.8%, respectively, with bovine sera and 78.1% and 99.0% with sheep sera. It was not possible to test the dog sera in the FPA.

Validation of the fluorescence polarization assay for detection of milk antibody to Brucella abortus.

A fluorescence polarization assay (FPA) for detection of antibody to Brucella abortus in individual milk samples was developed and validated. Samples from 190 cattle from which B. abortus was isolated; milk samples from cattle in herds infected with B. abortus (n = 1,086) and positive in the milk ring test (MRT), as well as milk samples from Canadian cattle (with no evidence of brucellosis, n = 2,974) were tested by the indirect enzyme immunoassay (IELISA) and the FPA. The sensitivity (based on samples from culture positive cattle) and specificity (based on Canadian milk samples) of the IELISA and the FPA were 100%. The relative sensitivity value obtained with milk from cattle of infected herds and the specificity values of the IELISA were 98.5 and 99.9%, respectively. The relative sensitivity and specificity of the FPA with the same samples were 82.2 and 99.4% using a cutoff value of 90 millipolarization units (mP). The low relative sensitivity value of the FPA was shown, by competitive enzyme immunoassay (CELISA), to be due to vaccinal antibody (assumed as vaccinal antibody against B. abortus Sl19 is excluded by the FPA and CELISA but not by the MRT and the IELISA), present in some of the milk samples. The FPA is a homogeneous assay which, unlike the MRT and the IELISA, may be used for testing in the field.

Fluorescence polarization assay for the diagnosis of bovine brucellosis: adaptation to field use.

A fluorescence polarization assay (FPA) was used to test whole blood samples prepared by mixing blood cells from cattle without exposure to Brucella abortus (B. abortus) with sera from animals with confirmed (bacteriologically) infection. A cut-off value between negative and positive values was initially established to be 87.2mP. This value was changed to 95mP to increase assay specificity without loss of sensitivity when testing blood samples from negative animals. The FPA technology was applied to whole blood samples in the field and to stored whole blood samples using two diluent buffers. Relative sensitivity and specificity values for the FPA performed in the field, based on buffered antigen plate agglutination test and competitive enzyme immunoassay results were 95.3 and 97.3%, respectively. However, to obtain maximum sensitivity and specificity, a cut-off value of 105mP was determined for fresh whole blood samples. The relative sensitivity and specificity values of the FPA when testing stored whole blood samples were 100% each using a 95mP cut-off.The usefulness of the FPA for testing whole blood samples in the field was demonstrated.

The retinal targets of centrifugal neurons and the retinal neurons projecting to the accessory optic system.

In birds, neurons of the isthmo-optic nucleus (ION), as well as "ectopic" neurons, send axons to the retina, where they synapse on cells in the inner nuclear layer (INL). Previous work has shown that centrifugal axons can be divided into two anatomically distinct types depending on their model of termination: either "convergent" or "divergent" (Ramon y Cajal, 1889; Maturana & Frenk, 1965). We show that cytochrome-oxidase histochemistry specifically labels "convergent" centrifugal axons and target neurons which appear to be amacrine cells, as well as three "types" of ganglion cells: two types found in the INL (displaced ganglion cells) and one in the ganglion cell layer. Labeled target amacrine cells have distinct darkly labeled "nests" of boutons enveloping the somas, are associated with labeled centrifugal fibers, and are confined to central retina. Lesions of the isthmo-optic tract abolish the cytochrome-oxidase labeling in the centrifugal axons and in the target amacrine cells but not in the ganglion cells. Cytochrome-oxidase-labeled ganglion cells in the INL are large; one type is oval and similar to the classical displaced ganglion cells of Dogiel, which have been reported to receive centrifugal input; the other type is rounder. Rhodamine beads injected into the accessory optic system results in retrograde label in both types of cells, showing that two distinct types of displaced ganglion cells project to the accessory optic system in chickens. The ganglion cells in the ganglion cell layer that label for cytochrome oxidase also project to the accessory optic system. These have proximal dendrites that ramify in the outer inner plexiform layer.(ABSTRACT TRUNCATED AT 250 WORDS)

A framework for community assessment: designing and conducting a survey in a Hispanic immigrant and refugee community.

This article introduces a framework for the study of access to medical care that has been used extensively in national and local surveys, and demonstrates its application to an assessment of health and health care needs in a Hispanic immigrant and refugee community. The presentation of the framework, study design, findings, and implications for research and planning points out the utility of this framework for organizing systematic community assessment data-gathering activities; demonstrates how such an assessment could be incorporated into a public health nursing curriculum or readily adopted by public health nurse professionals in their communities; illustrates the potential for effective partnerships between public health practitioners and academics in conducting and disseminating the findings; and provides a broader conceptual, empirical, and policy-oriented context in which to view local community-assessment activities and their relevance for health policy and program development.

Spatial organization of the retinal projection to the avian lentiform nucleus of the mesencephalon.

Utilizing the horseradish peroxidase retrograde tracing technique and the 2-deoxy-D-glucose metabolic mapping technique, we have demonstrated in chickens the distribution of retinal ganglion cells that project to the lentiform nucleus of the mesencephalon (LM) and the retinotopic organization of the projection in the LM. Retinal ganglion cells labeled after a nearly complete injection into the LM were found in the four quadrants, distributed in a wide horizontal belt lying along both sides of the retinal equator and stretching from the temporal to the nasal retina. The HRP-labeled cells, which appeared round or oval, ranged from 25 to 840 micron 2 in size with most in the smaller size range. Results of partial HRP injections into the LM and metabolic mapping patterns in the LM produced by stimulation of half the retina with horizontal visual motion suggest that there is an orderly mapping of the retina onto the LM. The inferior temporal quadrant projects to the rostrodorsal LM; the inferior nasal quadrant projects to the caudodorsal LM. The superior temporal quadrant projects to the middle and ventral LM, extending from the rostral to the caudal pole, whereas the superior nasal quadrant projects to a small zone in the caudal LM. The mapping of the retinal quadrants in the LM is remarkably similar to that reported in the optic tectum of birds. We suggest that a common embryological anlage with the optic tectum and the arrangement of retinal axons in the optic tract are important factors in establishing the retinotopic organization of the LM.