Clinical consequences of heparin-free hemodialysis

Heparin-free hemodialysis (HF-HD) has been increasingly used in patients at risk for bleeding, especially in the intensive care unit (ICU). Lack of heparin can reduce solute clearances in continuous hemofiltration; the effect on HD is undefined. Failure to recognize an effect of the anticoagulation strategy upon delivered clearance could contribute to the known problem of underdialysis in the ICU. In addition, the consequences of "locking" dialysis catheters with concentrated heparin solutions are also unclear. This study was designed to define the clinically relevant consequences of HF-HD and catheter locking. In part I, we performed 200 HD treatments on inpatients, of which 100 were performed with heparin, and 100 were performed as HF-HD. We calculated prescribed and delivered Kt/V and dialysis efficiency. In part II, a separate group of 14 patients undergoing HF-HD via central venous catheters had measurement of activated partial thromboplastin time (aPTT) during the last hour of dialysis, as well as 15, 60, and 240 min after catheters were locked with 1:5000 heparin. The prescribed Kt/V was 1.74+/-0.31 for standard HD with heparin vs. 1.66+/-0.36 for HF-HD (p=ns). The delivered Kt/V was 1.42+/-0.32 vs. 1.36+/-0.38 (p=ns). Efficiency was 0.82 vs. 0.84 (p=ns). Baseline aPTT was 28+/-5 s, and increased to 126+/-54 s, 15 min after locking (p<0.0001) and to 71+/-50 s, 60 min after locking (p=0.005). By 240 min, the mean aPTT had fallen to 33+/-9 s (p=0.03), although individual values were still as high as 50 s. The HF technique does not compromise delivery of dialysis to inpatients. Increased treatment time is not necessary. Locking catheters with heparin after HF-HD resulted in prolonged unintentional anticoagulation.     

A Six-Factor Structure of Personality-Descriptive Adjectives: Solutions From Psycholexical Studies in Seven Languages.

Standard psycholexical studies of personality structure have produced a similar 6-factor solution in 7 languages (Dutch, French, German, Hungarian, Italian, Korean, Polish). The authors report the content of these personality dimensions and interpret them as follows: (a) a variant of Extraversion, defined by sociability and liveliness (though not by bravery and toughness); (b) a variant of Agreeableness, defined by gentleness, patience, and agreeableness (but also including anger and ill temper at its negative pole); (c) Conscientiousness (emphasizing organization and discipline rather than moral conscience); (d) Emotionality (containing anxiety, vulnerability, sentimentality, lack of bravery, and lack of toughness, but not anger or ill temper); (e) Honesty-Humility; (f) Intellect/Imagination/Unconventionality. A potential reorganization of the Big Five factor structure is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrochemistry in large unilamellar vesicles. The distribution of 1-naphthol studied by square wave voltammetry

1-Naphthol (NPh) behavior in water and in large unilamellar vesicles (LUVs) formed with the phospholipid 1,2-di-oleoyl-sn-glycero-3-phosphatidylcholine (DOPC) was studied by square wave (SWV) and cyclic voltammetry (CV) techniques and, compared with emission spectroscopy studies. In DOPC LUV media, the redox behavior of NPh shows that the molecule undergoes a partition process between two pseudophases, the water and the LUV bilayer. The NPh electrochemical responses allow us to propose a model to explain the electrochemical experimental results and, in conjunction with our measurements, to calculate the NPh partition constant (K) value between the pseudophases. The K value coincides with the one obtained through emission spectroscopy. Beside the K value, our electrochemical model allows us to calculate the diffusion coefficient (D_LUV) for DOPC LUV which coincides with the D_LUV value obtained through dynamic light scattering (DLS). Thus, our data clearly show that the electrochemical measurements could be a powerful alternative approach to investigate the behavior of non-ionic electroactive molecules embed in a confined environment such as the LUV bilayer.     

Geometry of the Icosikaidigon in Orvieto Cathedral

The rose window on the main façade of Orvieto cathedral is unique because its design is based on a 22-sided polygon. It is well known that the icosikaidigon cannot be constructed using only a compass and a straightedge. Therefore, using a geometric/statistical approach, we intend to unveil which approximate construction method was used by the sculptor to draw this unique rose window.     

Switch-based packing technique to reduce traffic and latency in token coherence

Token Coherence is a cache coherence protocol able to simultaneously capture the best attributes of traditional protocols: low latency and scalability. However it may lose these desired features when (1) several nodes contend for the same memory block and (2) nodes write highly-shared blocks. The first situation leads to the issue of simultaneous broadcast requests which threaten the protocol scalability. The second situation results in a burst of token responses directed to the writer, which turn it into a bottleneck and increase the latency. To address these problems, we propose a switch-based packing technique able to encapsulate several messages (while in transit) into just one. Its application to the simultaneous broadcasts significantly reduces their bandwidth requirements (up to 45%). Its application to token responses lowers their transmission latency (by 70%). Thus, the packing technique decreases both the latency and coherence traffic, thereby improving system performance (about 15% of reduction in runtime).     

Linking Interfacial Step Structure and Chemistry with Locally Enhanced Radiation‐Induced Amorphization at Oxide Heterointerfaces

Nanostructured materials and their interfaces have attracted recent interest for their functionality in a wide variety of different applications. However, the origins of these properties in several instances remain unknown. One promising aspect of nanomaterials is their role in materials design for mitigating radiation damage. In particular, engineered radiation tolerant materials would exploit the presence of internal interfaces to act as recombination centers and suppress damage accumulation. Realizing this promise, however, requires a fundamental understanding of how radiation‐induced defects interact with interfaces. Thus, studying the interfacial atomic structure and chemistry before and after irradiation is critical. In this study, we have performed transmission electron microscopy on a series of pristine and ion‐irradiated oxide interfaces to probe radiation‐induced effects. The CeO₂/SrTiO₃ interface, chosen as a model system for these studies, is characterized by differences in SrTiO₃ terminations or steps. Our salient result is that steps are centers for preferential amorphization in SrTiO₃, which we attribute to defect flow across the interface induced by non‐stoichiometry in CeO₂. The study concludes the interfacial atomic ordering in the form of steps thereby modifies the response to ion irradiation and suggests interface patterning as another parameter to functionalize radiation tolerant materials.     

Spatial learning and memory deficits after telencephalic ablation in goldfish trained in place and turn maze procedures.

The present work investigated whether the fish telencephalon is involved in spatial learning based on place strategies in a manner similar to mammalian hippocampus. Goldfish were trained in a 4-arm maze in a room with relevant spatial cues. Sham and to-be-ablated subjects were trained in each of 4 experimental procedures designed as follows: place, turn, place-turn, and control. After acquisition, complete ablations of both telencephalic hemispheres for the experimental groups were carried out. The results showed that ablation exclusively impaired performance in animals using place strategies; in these, accuracy fell to chance level during both postsurgery retraining and reversal periods. In the other groups, ablation of the telencephalon did not induce any significant deficit. These results suggest that the fish telencephalon plays a crucial role in complex place learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement of magnitude and direction of velocity in high-temperature liquid metals. Part II: Experimental measurements

Experimental research work on the application of the sphere melting technique to measure magnitude as well as direction of velocity in liquid metals is the focus of Part II of this series of articles. The sphere melting time is detected by means of a sensing wire, which is connected to a specially designed electrical circuit. A novel apparatus is used whereby liquid metal is rotated with a specified tangential velocity. To measure the magnitude of velocity, the sensing wire of the sphere melting is located at the center of the sphere. To detect the direction of flow, three sensing wires are employed. These wires are placed at strategic locations inside the sphere and detect the melting times at three different locations. The ratio of the melting times of these locations identifies the direction of the flow. The experimental results are compared against model predictions. In addition, an error analysis is carried out to discover the possible sources of error in the detection of metal velocity. The liquid metals used in this research work are commercial purity aluminum and AZ91 magnesium alloy.     

Teaching of wave propagation phenomena using MATLAB GUIs at the Universidad Politecnica of Valencia

The use of interactive graphics and animations is a fundamental tool for teaching electromagnetic concepts. This is especially true for the study of wave propagation, where the propagation properties of waves are hard to understand with oral explanations or simple, static, chalk drawings on the blackboard. The traditional blackboard or the more recent slides are increasingly giving way to the use of electronic material for illustrating propagation phenomena in the classroom. Several works where computer tools are used in order to improve electromagnetic teaching have already been published (Mathematica, Maple, MATHCAD, Java, MATLAB, Mefisto, and VRML). Of all these tools, MATLAB has been chosen to design several graphical user interfaces (GUIs) that allow the creation of wave-propagation animations under user-specified conditions. These GUIs have been assessed for the teaching of a course on "Electromagnetic Fields and Waves." The main objectives of the course are the knowledge of the main parameters of plane and guided waves, and an understanding of the main propagation phenomena of these two types of waves.