Bouyant density, conversion formulae, and the mole percent guanosine + cytosine content of Desulfovibrio sp

A reevaluation of the original buoyant density conversion formula used to calculate the molar percentage guanosine + cytosine (% G + C) contents of the accepted species of genus Desulfovibrio has been undertaken. It would appear that the formula used gives values 4-5% lower than those obtained using formulae more generally cited in modern literature. Recalculations of % G + C content values for Lesulfovibrio DNA are presented using the formulae of three different workers, and are compared with those values originally used in the classification of genus Desulfovibrio.     

How capuchin monkeys (Cebus apella) quantify objects and substances.

Humans and nonhuman animals appear to share a capacity for nonverbal quantity representations. But what are the limits of these abilities? Results of previous research with human infants suggest that the ontological status of an entity as an object or a substance affects infants' ability to quantify it. We ask whether the same is true for another primate species-the New World monkey Cebus apella. We tested capuchin monkeys' ability to select the greater of two quantities of either discrete objects or a nonsolid substance. Participants performed above chance with both objects (Experiment 1) and substances (Experiment 2); in both cases, the observed performance was ratio dependent. This finding suggests that capuchins quantify objects and substances similarly and do so via analog magnitude representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Wideband 1.5?m optical receiver using travelling-wave laser amplifier

A high-sensitivity, wideband optical receiver using a travelling-wave laser amplifier in conjunction with a PIN photodiode and commercial 50? amplifier is described. A sensitivity of ?37 dBm at 1 Gbit/s has been achieved, with a 17dB net amplifier gain.     

Categorization of disoriented faces in the cerebral hemispheres of normal and commissurotomized subjects.

We examined the capacity of the cerebral hemispheres to process faces that deviate from canonical perspective. In Experiment 1, normal Ss performed a gender categorization of faces presented at varying angular orientations in the left visual field (LVF) or right visual field (RVF). Orientation affected processing speed, more so in the RVF than in the LVF. The function relating reaction times to disorientation of the faces was approximately monotonic and reflected the increased difficulty in extracting relevant configurational information as the faces were rotated from canonical perspective. In Experiment 2, 3 commissurotomized Ss performed the same task. They responded above chance in the 2 visual fields, and the pattern of their results was similar to that obtained with the normal Ss, but the effect of disorientation was considerably more pronounced. It is suggested that the right hemisphere contribution becomes more critical the further the visual pattern departs from conventional view. Issues regarding the specification of processes correcting for disorientation and comparison of normal and commissurotomized Ss are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship between sleep spindles and hypersomnia

Despite the substantial experimental literature that has accrued on factors associated with a reduction in neglect, few empirical studies have attempted to extrapolate these findings to clinical assessment and evaluate the efficacy of neglect-reducing strategies on patient performance. The current study developed a modified version of the Raven's Coloured Progressive Matrices (RCPM) by aligning the response alternatives in a column, in the right hemispace. Three groups of patients (right brain-damaged (RBD) with neglect, RBD without neglect, and orthopaedic controls) were administered abbreviated versions of the revised format, and performance was compared to the standard presentation format. The efficacy of left cues with the revised format was also investigated. Presence of neglect was assessed via the Schenkenberg Line Bisection Task and the Bells Test. Results showed a significant performance decrement among RBD neglect patients under all conditions. However, contrary to predictions, RBD neglect patients did not reveal significantly better performance on the revised version as compared to the standard presentation format. No significant effects associated with left side cueing were observed. The finding that no significant performance changes emerged as a function of stimulus modification and verbal prompts suggests that, although these manipulations may be employed by clinicians to maximize patient performance, empirical support for the efficacy of these procedures is lacking.     

Non-monophyly of the monogeneans?

There is currently no congruence between phylogenies based on morphology, in which the Monogenea are considered a monophylum, and molecular phylogenies based on 18S or 28S rDNA, in which the Monogenea are never considered monophyletic. However, all analyses based on morphology and sperm characters or molecular data found constantly the two subgroups composing the Monogenea, namely the Monopisthocotylea and Polyopisthocotylea (or Polyonchoinea and Oligonchoinea) to be independently monophyletic. This conflict concerns not only monophyly of the Monogenea, but also the relationships of the Monopisthocotylea and Polyopisthocotylea with the Trematoda (Digenea and Aspidogastrea) and Cestoda, and therefore the phylogeny of the parasitic Platyhelminthes as a whole. It is concluded that a reappraisal of morphological synapomorphies should be undertaken.     

The isotope effect and the influence of interstitial impurities on the hydrogen solubility limit in niobium and vanadium

The solubility limits for hydrogen and deuterium in niobium were determined resistometrically between 175 and 280°K before and after purification of the niobium by ultra-high vacuum treatment. No isotope effect was observed; neither was an interstitial impurity effect detected in the low concentration range studied. The solubility limits for hydrogen in vanadium were measured at temperatures between 230 and 325°K before and after additions of oxygen greater than 1000 at. ppm. Large concentrations of solute oxygen increase the apparent solubility limit for hydrogen in vanadium.     

Wetting Properties of Steel Surfaces Modified by Laser Interference Metallurgy

The wetting properties of 100Cr6 bearing steel surfaces modified using laser interference metallurgy (LIMET) are analyzed. The steel surfaces are structured with line‐like patterns with line‐spacing. The topography of the ridged surface is analyzed by means of white light interferometry and scanning electron microscopy and surface chemistry of the different topographic regions by Raman spectroscopy. Contact angle (CA) measurements are performed on modified and non‐irradiated surfaces, using bi‐distilled water and FVA2 industrial oil. The angles are measured parallel and perpendicular to the line‐pattern orientation. The topographical analysis shows steep line‐pattern produced by laser. Raman analysis indicates that the laser irradiation does not significantly change the chemical species of the modified surfaces. The CA measurements elucidates that the parallel orientation provides a better wetting of the surface, because the laser line‐pattern acts as capillary flow channels, whereas the perpendicular orientation imposes energy barrier thus preventing wetting. As expected, the wetting coverage is more effective for larger than for smaller periodic structures, due to the larger area of flat contact. These novel results highlight the relevant use of LIMET to tailor the wetting properties of steel surfaces.     

ST6GALNAC5 Expression Decreases the Interactions between Breast Cancer Cells and the Human Blood-Brain Barrier

The ST6GALNAC5 gene that encodes an α2,6-sialyltransferase involved in the biosynthesis of α-series gangliosides, was previously identified as one of the genes that mediate breast cancer metastasis to the brain. We have shown that the expression of ST6GALNAC5 in MDA-MB-231 breast cancer cells resulted in the expression of G_D1α ganglioside at the cell surface. By using a human blood-brain barrier in vitro model recently developed, consisting in CD34⁺ derived endothelial cells co-cultivated with pericytes, we show that ST6GALNAC5 expression decreased the interactions between the breast cancer cells and the human blood-brain barrier.