The effect of hemodialysis session on postural strategies in older end‐stage renal disease patients

Patients suffering from end‐stage renal disease experience multiple disabilities, such as muscle wasting, weakness, higher postural sway, and fall rates compared with healthy population, which has a negative effect on physical functioning and autonomy. The vital treatment of hemodialysis is recognized to induce important post‐hemodialysis fatigue, hypotension, cramps, and headache due to the rapid fluid redistribution, among others. Nevertheless, even the well‐known negative effect of aforementioned consequences of hemodialysis treatment, its effect on physical function, especially postural balance, is unclear. Thus, this study hypothesized the adverse effect of hemodialysis treatment on postural sway in 12 end‐stage renal disease patients (mean age 63.3 ± 11 years) through the analysis of center‐of‐pressure (COP) trajectories recorded before and immediately after hemodialysis session. Evident postural alterations were observed at post‐hemodialysis balance assessment for COP position‐based (Fs < 7.7, P < 0.02) and COP velocity‐based variables (Fs > 2.33, P < 0.05), without changes in complexity of COP time series in anteroposterior and mediolateral directions. These results suggest that period after hemodialysis treatment is particularly unsafe, as evidenced by important disability in postural control, and highlight the importance of the medical support and falls‐related prevention strategies of these older frail patients after hemodialysis treatment.     

Determination of Bile Acids in Piglet Bile by Solid Phase Extraction and Liquid Chromatography-Electrospray Tandem Mass Spectrometry

An LC/MS/MS‐based method was developed for the determination of individual bile acids (BA) and their conjugates in porcine bile samples. The C18‐based solid‐phase extraction (SPE) procedure was optimized so that all 19 target BA and their glycine and taurine conjugates were collected with high recoveries for standards (89.1–100.2 %). Following this, all 19 compounds were separated and quantified in a single 12 min chromatographic run. The method was validated in terms of linearity, sensitivity, accuracy, precision, and recovery. An LOD in the low ppb range with measured precisions in the range of 0.5–9.3 % was achieved. The recoveries for all of the 19 analytes in bile samples were all >80 %. The validated method was successfully applied to the profiling of BA and their conjugates in the bile from piglets treated with exogenous glucagon‐like peptide‐2 (GLP‐2) in a preclinical model of neonatal parenteral nutrition‐associated liver disease (PNALD). The method developed is rapid and could be easily implemented for routine analysis of BA and their conjugates in other biofluids or tissues.     

The Effect of Grain Size on the Cyclic Oxidation of NiCoCrAlY

NiCoCrAlY samples were fabricated via spark-plasma sintering with and without prior cryomilling of the as-received powder. Thermal cycling oxidation tests were conducted at 1000°C in air for up to 200 1-h cycles. The mass gain data indicate a notably lower mass gain for the cryomilled NiCoCrAlY sample. In both the conventional and cryomilled samples, scanning electron microscopy and x-ray diffraction data indicate a single-layer oxide scale of α-alumina has formed, having undergone a transition from θ-alumina during oxidation testing. Spallation in the conventional sample allowed a significant amount of internal spinel oxide formation, and this was not found in the cryomilled sample. The difference in behavior is attributed to increased pathways for aluminum diffusion to the surface and nucleation sites for the α-alumina transition, as well as improved scale adhesion through nanostructuring and stress relief through the accelerated θ–α transition.     

Wavefront watermarking of technical and biological samples using digital random phase modulation and phase retrieval

A technique for digital watermarking of smooth object wavefronts using digital random phase modulation and multiple-plane iterative phase retrieval is demonstrated experimentally. A complex-valued watermark is first encrypted using two random phase masks of known distributions before being superposed onto a set of host wavefront intensity patterns. Encryption scaling factor and depth of randomization of the masks are optimized such that the amplitude and phase watermarks are decrypted successfully and are not distorting the host wavefront. Given that the watermarked intensity patterns and the numerous decryption keys are available (i.e. distances between recording planes, light source wavelength, pixel size, random phase masks and their distances to the planes are all known), increasing the number of watermarked patterns used results in enhanced quality of decrypted watermarks. The main advantage of wavefront watermarking via the phase retrieval approach compared to the holographic approach is the avoidance of reference wave-induced aberration. Watermarking of wavefronts from lenses and unstained human cheek cells demonstrate the effectiveness of the technique.     

Tubulin polyglycylation in Platyhelminthes: diversity among stable microtubule networks and very late occurrence during spermiogenesis

The distribution of glycylated tubulin has been analyzed in different populations of stable microtubules in a digenean flatworm, Echinostoma caproni (Platyhelminthes). Two cellular types, spermatozoa and ciliated excretory cells, have been analyzed by means of immunofluorescence, immunogold, and immunoblotting techniques using two monoclonal antibodies (mAbs), AXO 49, and TAP 952, specifically directed against differently glycylated isoforms of tubulin. The presence of glycylated tubulin in the two cell types was shown. However, the differential reactivities of TAP 952 and AXO 49 mAbs with the two axoneme types suggest a difference in their glycylation level. In addition, within a single cell, the spermatozoon, cortical microtubules underlying the flagellar membrane, and axonemal microtubules were shown to comprise different tubulin isoforms, the latter ones only being labelled with one of the antiglycylated tubulin mAbs, TAP 952. Similarly, the antiacetylated (6-11B-1) and polyglutamylated (GT335) tubulin mAbs decorated the two types of axonemal microtubules, but not the cortical ones. From these data, a subcellular sorting of posttranslationally modified tubulin isoforms within spermatozoa, on the one hand, and a cellular sorting of glycylated isoforms inside the whole organism, on the other hand, is demonstrated in the flatworm E. caproni. Last, a sequential occurrence of tubulin posttranslational modifications was observed in the course of spermiogenesis. Acetylation appears first, followed shortly by glutamylation; glycylation takes place at the extreme end of spermiogenesis and, specifically, in a proximo-distal process. Thus in agreement with, and extending other studies [Bré et al., 1996], glycylation appears to close the sequence of posttranslational events occurring in axonemal microtubules during spermiogenesis.     

Stealth malware analysis from kernel space with Kolumbo

Most of today’s malware are able to detect traditional debuggers and change their behavior whenever somebody tries to analyze them. The analysis of such malware becomes then a much more complex task. In this paper, we present the functionalities provided by the Kolumbo kernel module that can help simplify the analysis of malware. Four functionalities are provided for the analyst: system calls monitoring, virtual memory contents dumping, pseudo-breakpoints insertion and eluding anti-debugging protections based on ptrace. The module as been designed to minimize its impact on the system and to be as undetectable as possible. However, it has not been conceived to analyze programs with kernel access.     

The resource discovery network: Www.rdn.ac.uk

The Dublin Core Metadata Element Set is a simple set of elements intended primarily for use in describing Internet based resources. This short guide, written with those new to the Dublin Core in mind, gives an overview of the Dublin Core elements and shows by example how to embed them into HTML Web pages. It must be noted when reading this guide that the Dublin Core is still in an evolutionary phase at the time of writing.     

Differential hemispheric processing of faces: Methodological considerations and reinterpretation.

Examines the procedures and stimuli (physiognomies) used in lateralized face recognition experiments with normal Ss, as well as in related perceptual and identification experiments. Results reveal that in general a left visual field (right hemisphere) advantage is obtained when: (a) stimulus information is degraded; (b) faces to be compared are highly discriminable; (c) set of unfamiliar faces is used; and (d) task requirements allow a lax criterion of recognition. These conditions seem to make holistic processing adequate for the task; if the conditions require analytic judgments, then a right visual field (left hemisphere) advantage may be obtained. Thus, no hemifield has an inherent or absolute advantage and these procedural conditions may critically determine what hemifield advantage is observed in any given experiment with faces (or other types of stimuli). Apparently, both hemispheres may contribute to the processing of faces but their contributions vary as a function of task demands. A right hemisphere advantage may reflect an enhanced role of the processes of configuration, completion, categorization, or set. A left hemisphere advantage need not involve the language function but it may reflect a genuine visuospatial contribution. (60 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adaptive hypertext navigation based on user goals and context

Hypertext systems allow flexible access to topics of information, but this flexibility has disadvantages. Users often become lost or overwhelmed by choices. An adaptive hypertext system can overcome these disadvantages by recommending information to users based on their specific information needs and preferences. Simple associative matrices provide an effective way of capturing these user preferences. Because the matrices are easily updated, they support the kind of dynamic learning required in an adaptive system.HYPERFLEX, a prototype of an adaptive hypertext system that learns, is described. Informal studies with HYPERFLEX clarify the circumstances under which adaptive systems are likely to be useful, and suggest that HYPERFLEX can reduce time spent searching for information by up to 40%. Moreover, these benefits can be obtained with relatively little effort on the part of hypertext authors or users.The simple models underlying HYPERFLEX's performance may offer a general and useful alternative to more sophisticated modelling techniques. Conditions under which these models, and similar adaptation techniques, might be most useful are discussed.     

Image generation and processing of generated images in the cerebral hemispheres.

Recent computational models describing the contribution of the cerebral hemispheres to visual imagery have suggested an exclusive capacity of the left hemisphere to generate multipart images. A brief review of relevant findings indicates that the evidence presented in support of this suggestion is not entirely compelling; this prompted a reexamination of this issue in a lateral tachistoscopic study on normal adults. Sixteen subjects participated in two experiments in which they had to decide whether or not a lowercase letter contained a segment extending above or below the main body of the letter. This decision was made directly on lowercase letters in one experiment (perceptual task) and on their generated images in the other experiment (imagery task). The quality of the letters (clear or blurred) and the retinal eccentricity of stimulus presentation (small or large) were orthogonally manipulated. The perceptual task yielded no main effect of visual field but a significant interaction of visual field and letter quality. By contrast, the imagery task resulted in a left visual-field superiority but no interaction involving the visual fields—a departure from predictions based on current models of visual imagery. In addition, the pattern of results in the imagery task corresponded to that obtained with blurred letters in the perceptual task, suggesting limitations in spatial resolution of visual images. Implications of these results for models of cerebral lateralization and visual imagery are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)