Prosthetic urinary sphincter

A pump/valve unit for controlling the inflation and deflation of a urethral collar in a prosthetic urinary sphincter device is described. A compressible bulb pump defining a reservoir was integrated with a valve unit for implantation. The valve unit includes a movable valve member operable by depression of a flexible portion of the valve unit housing for controlling fluid flow between the reservoir and collar; and a pressure sensing means which operates the valve member to relieve an excess pressure in the collar should too much pressure be applied by the patient

Comparison of Otolith and Scale Age Determinations for Freshwater Drum from the Mississippi River

A comparative aging study was conducted using scales and otoliths from 123 freshwater drum collected in Pool 14 of the Mississippi River. Two independent readings by 2 investigators resulted in full agreement on ages assigned using otoliths, but only 64% agreement using the scale method. A final age was determined for the remaining scale samples based on the most commonly assigned age. However, there was no agreement on assigned ages for 12% of the scales examined. Otoliths were validated as an accurate method for aging freshwater drum by age frequency histograms for 3 consecutive years. The marked 3-year periodicity in appearance of strong year-classes allowed these strong year-classes to be followed through successive years of study providing a check on the reliability of this aging method. Scales were concluded to be only 61% reliable for aging freshwater drum. The observed trend indicated that assigned ages using scales were commonly overestimated for fish age 9 and younger and underestimated for older fish

Temporal and spatial variations of gyne production in the ant Formica exsecta

Social insects have become a general model for tests of sex allocation theory. However, despite tremendous interest in the topic, we still know remarkably little about the factors that cause dramatic differences in sex allocation among local populations. A number of studies have suggested that environmental factors may influence sex allocation in ant populations. In polygynous (multiple queens per nest) populations of the ant Formica exsecta, sex allocation is extremely male biased at the population level, with only a small proportion of nests producing any gynes (female reproductive brood). We analysed the proportion of gyne-producing nests in 12 F. exsecta populations during three successive breeding seasons and found considerable temporal and spatial variability in the proportion of gyne-producing nests. The populations differed in a number of characteristics, including elevation, nest density, size of the nest mound, and number of nests per population. However, the proportion of gyne-producing nests was not associated with any of these geographic and demographic variables. Moreover, differences between populations in the production of gynes were not consistent between years. Thus, the proportion of gyne-producing nests appears to vary stochastically, perhaps because of stochastic variations in environmental factors. For example, year-to-year variations in the proportion of gyne-producing nests were associated with differences in spring weather conditions between years. The finding that gyne production varies greatly between years suggests that it may not always be adaptive at a local scale

Operational Comparison of Three Electrofishing Systems

Three different electrofishing systems were compared to determine their relative efficiency with respect to species and numbers of fish collected. These results indicated that modifications or changes in electrofishing gear during a monitoring program should not be made unless it can be demonstrated that collecting efficiency is not altered

Motherhood, Moral Authority and the Charismatic Matriarch in the Aftermath of Lethal Violence

Images of maternal suffering are an evocative and powerful means of communication in a world where the private grief of victims has increasingly become subject to commodification and public consumption. This article looks at the influence of bereaved mothers as symbols of respect, peace and dignity in the aftermath of violence, and as a result their persuasive presence in family activism. Drawing upon two case studies, this article explores the importance of victims’ stories in public life and, in particular, the presence of the charismatic matriarch in creating communities of solidarity, raising awareness of harms that have previously gone unheard and prompting policy change. It considers the ‘canonical’ story of the mother in public life and concludes by arguing that more attention should be paid to victims’ stories and their influence on policy-making, politics and eventually in becoming public grievances

The Mechanical Properties of Individual, Electrospun Fibrinogen Fibers

We used a combined atomic force microscope (AFM)/fluorescence microscope technique to study the mechanical properties of individual, electrospun fibrinogen fibers in aqueous buffer. Fibers (average diameter 208 nm) were suspended over 12 μm-wide grooves in a striated, transparent substrate. The AFM, situated above the sample, was used to laterally stretch the fibers and to measure the applied force. The fluorescence microscope, situated below the sample, was used to visualize the stretching process. The fibers could be stretched to 2.3 times their original length before breaking; the breaking stress was 22·106 Pa. We collected incremental stress-strain curves to determine the viscoelastic behavior of these fibers. The total stretch modulus was 16·106 Pa and the relaxed, elastic modulus was 6.7·106 Pa. When held at constant strain, electrospun fibrinogen fibers showed a fast and slow stress relaxation time of 3 and 56 seconds. Our fibers were spun from the typically used 90% 1,1,1,3,3,3-hexafluoro-2-propanol (90-HFP) electrospinning solution and resuspended in aqueous buffer. Circular dichroism spectra indicate that alpha-helical content of fibrinogen is ~70% higher in 90-HFP than in aqueous solution. These data are needed to understand the mechanical behavior of electrospun fibrinogen structures. Our technique is also applicable to study other, nanoscopic fibers

Derivation of an Analytical Model to Calculate Junction Depth in HgCdTe Photodiodes

Presents an enhanced analytical model to calculate junction depth and Hg interstitial profile during n-on-p junction formation in HgCdTe photodiodes. Detailed information on the enhanced model; Function of the model; Information on HgCdTe; Detailed information on how the model was obtained

Absorption Spectral Slopes and Slope Ratios as Indicators of Molecular Weight, Source, and Photobleaching of Chromophoric Dissolved Organic Matter

A new approach for parameterizing dissolved organic matter ( DOM) ultraviolet-visible absorption spectra is presented. Two distinct spectral slope regions ( 275-295 nm and 350-400 nm) within log-transformed absorption spectra were used to compare DOM from contrasting water types, ranging from wetlands (Great Dismal Swamp and Suwannee River) to photobleached oceanic water ( Atlantic Ocean). On the basis of DOM size-fractionation studies ( ultrafiltration and gel filtration chromatography), the slope of the 275-295- nm region and the ratio of these slopes (SR; 275-295- nm slope : 350-400- nm slope) were related to DOM molecular weight ( MW) and to photochemically induced shifts in MW. Dark aerobic microbial alteration of chromophoric DOM ( CDOM) resulted in spectral slope changes opposite of those caused by photochemistry. Along an axial transect in the Delaware Estuary, large variations in SR were measured, probably due to mixing, photodegradation, and microbial alteration of CDOM as terrestrially derived DOM transited through the estuary. Further, SR varied by over a factor of 13 between DOM-rich wetland waters and Sargasso Sea surface waters. Currently, there is no consensus on a wavelength range for log-transformed absorption spectra. We propose that the 275-295- nm slope be routinely reported in future DOM studies, as it can be measured with high precision, it facilitates comparison among dissimilar water types including CDOM-rich wetland and CDOM-poor marine waters, and it appears to be a good proxy for DOM MW. © 2008, by the American Society of Limnology and Oceanography, Inc

Current research into brain barriers and the delivery of therapeutics for neurological diseases: a report on CNS barrier congress London, UK, 2017.

This is a report on the CNS barrier congress held in London, UK, March 22-23rd 2017 and sponsored by Kisaco Research Ltd. The two 1-day sessions were chaired by John Greenwood and Margareta Hammarlund-Udenaes, respectively, and each session ended with a discussion led by the chair. Speakers consisted of invited academic researchers studying the brain barriers in relation to neurological diseases and industry researchers studying new methods to deliver therapeutics to treat neurological diseases. We include here brief reports from the speakers

Density functional theory based study of graphene and dielectric oxide interfaces

We study the effects of insulating oxides in their crystalline forms on the energy band structure of monolayer and bilayer graphene using a \textit{first principles} density functional theory based electronic structure method and a local density approximation. We consider the dielectric oxides, SiO$_{2}$ ($\alpha$-quartz) and Al$_{2}$O$_{3}$ (alumina or $\alpha$-sapphire) each with two surface terminations. Our study suggests that atomic relaxations and resulting equilibrium separations play a critical role in perturbing the linear band structure of graphene in contrast to the less critical role played by dangling bonds that result from cleaving the crystal in a particular direction. We also see that with the addition of a second graphene layer, the Dirac cone is restored for the quartz surface terminations. Alumina needs more than two graphene layers to preserve the Dirac cone. Our results are at best semi-quantitative for the common amorphous forms of the oxides considered. However, crystalline oxides for which our results are quantitative provide an interesting option for graphene based electronics, particularly in light of recent experiments on graphene with crystalline dielectrics (hexagonal BN) that find considerable improvements in transport properties as compared to the those with amorphous dielectrics