bluuebunny/crossref_metadata_2025 huggingface dataset:
Medication Errors, Routines, and Differences Between Perioperative and Non‐perioperative Nurses
Authors: Treiber Linda A. , Jones Jackie H.
Published: August 2012

Despite efforts to reduce the incidence of perioperative medication errors, these errors continue to be a problem. We examined written accounts from 16 nurses who discussed medication errors in the perioperative environment and 11 nurses who provided additional information about perioperative errors, nursing education, and the state of health care. Preoperative medication errors were the most frequently reported perioperative medication errors. Other reported errors involved intraoperative medication administration, IV sedation, and “close call” events. Reasons for errors included production pressure, complacency, and failure to follow established routines. We also identified evidence of self‐blame and lack of understanding between nursing units and specialty areas. We compared attitudes and opinions of nurses working in perioperative settings with those of nurses working in non‐perioperative areas and found both similarities and differences in the perceptions of medication errors and why they occur.
Intraoperatively Acquired Pressure Ulcers and Perioperative Normothermia: A Look at Relationships
Authors: Fred Cynthia , Ford Sharon , Wagner Doreen , VanBrackle Lewis
Published: August 2012

The risk of developing an intraoperatively acquired pressure ulcer (IAPU), which is recognized as a significant complication of deep tissue injury occurrence, is associated with duration of surgery and patient positioning. There is a strong association between hypothermia, tissue viability, and surgical site infections; however, the relationship between hypothermia and pressure ulcers has not been fully explored. We examined the incidence of pressure ulcers in surgical patients and determined that there is a relationship between maintaining perioperative normothermia and a reduction in IAPU development. We used a retrospective, explanatory, nonexperimental design, and we fit a binary logistic model to the data. This study shows that patients at higher risk for developing an IAPU include those who are critically ill, have a low Braden Scale skin assessment score, are thin, and are male with at least a 1° F (1.8° C) drop in temperature. These are important risks for perioperative nurses to take into account during care of surgical patients. More perioperative research is needed to identify ways to reduce risk, provide close assessment of high‐risk patients, and implement the identified risk‐reduction strategies.
Oral misoprostol as first‐line care for incomplete abortion in Burkina Faso
Authors: Blandine Thieba , Ouattara Adama Z. , Coral Angela , Hassane Cisse , Clotaire Hien , Dao Blami , Lankoande Jean , Diop Ayisha , Blum Jennifer
Published: August 2012

Objective

To explore 400‐μg sublingual misoprostol as primary treatment in lower‐level facilities with no previous experience providing postabortion care.

Methods

Women presenting with incomplete abortion were offered a single dose of 400‐μg sublingual misoprostol. Incomplete abortion was defined as uterine size consistent with fewer than 12 weeks of gestation, open cervical os, and reports of past or present history of vaginal bleeding. Women returned to the clinic 1 week after misoprostol administration for follow‐up. At that time, they were discharged if the uterine evacuation was a success or were offered a second follow‐up visit or surgical completion if still incomplete.

Results

One‐hundred women received misoprostol; outcome data were unavailable for 1 woman. Complete uterine evacuation was achieved for 97 (98.0%) women. Satisfaction was high, with nearly all women indicating that they were “satisfied” (n = 57 [57.6%]) or “very satisfied” (n = 41 [41.4%]) with their experience. Adverse effects were considered “tolerable” by 72 of 97 (74.2%) women. Ninety‐seven of 99 (98.0%) participants indicated that they would choose misoprostol for incomplete abortion care in the future and 95 of 97 (97.9%) stated that they would recommend it to a friend.

Conclusion

Misoprostol is a viable option for treatment of incomplete abortion at mid‐level facilities.

Clinical trials.gov: NCT00466999.
Aspect ratio dependence of heat transport by turbulent Rayleigh–Bénard convection in rectangular cells
Authors: Zhou Quan , Liu Bo-Fang , Li Chun-Mei , Zhong Bao-Chang
Published: August 2012

We report high-precision measurements of the Nusselt number $Nu$ as a function of the Rayleigh number $Ra$ in water-filled rectangular Rayleigh–Bénard convection cells. The horizontal length $L$ and width $W$ of the cells are 50.0 and 15.0 cm, respectively, and the heights $H= 49. 9$, 25.0, 12.5, 6.9, 3.5, and 2.4 cm, corresponding to the aspect ratios $({\Gamma }_{x} \equiv L/ H, {\Gamma }_{y} \equiv W/ H)= (1, 0. 3)$, $(2, 0. 6)$, $(4, 1. 2)$, $(7. 3, 2. 2)$, $(14. 3, 4. 3)$, and $(20. 8, 6. 3)$. The measurements were carried out over the Rayleigh number range $6\ensuremath{\times} 1{0}^{5} \lesssim Ra\lesssim 1{0}^{11} $ and the Prandtl number range $5. 2\lesssim Pr\lesssim 7$. Our results show that for rectangular geometry turbulent heat transport is independent of the cells’ aspect ratios and hence is insensitive to the nature and structures of the large-scale mean flows of the system. This is slightly different from the observations in cylindrical cells where $Nu$ is found to be in general a decreasing function of $\Gamma $, at least for $\Gamma = 1$ and larger. Such a difference is probably a manifestation of the finite plate conductivity effect. Corrections for the influence of the finite conductivity of the top and bottom plates are made to obtain the estimates of $N{u}_{\infty } $ for plates with perfect conductivity. The local scaling exponents ${\ensuremath{\beta} }_{l} $ of $N{u}_{\infty } \ensuremath{\sim} R{a}^{{\ensuremath{\beta} }_{l} } $ are calculated and found to increase from 0.243 at $Ra\simeq 9\ensuremath{\times} 1{0}^{5} $ to 0.327 at $Ra\simeq 4\ensuremath{\times} 1{0}^{10} $.
Fragmented Ethnopolitical Social Representations of a Territorial Peace Agreement: The Mindanao Peace Talks
Authors: Montiel Cristina Jayme , de Guzman Judith M. , Macapagal Ma. Elizabeth J.
Published: August 2012

This article examines fractures in the social representations of a contested peace agreement in the longstanding territorial conflict of Mindanao. We compared representational structures and discourses about the peace talks among Muslims and Christians. Study One used an open-ended survey of 420 Christians and Muslims from two Mindanao cities identified with different Islamised tribes, and employed the hierarchical evocation method to provide representational structures of the peace agreement. Study Two contrasted discourses about the Memorandum of Agreement between two Muslim liberation fronts identified with separate Islamised tribes in Mindanao. Findings show unified Christians’ social representations about the peace agreement. However, Muslims’ social representations diverge along the faultlines of the Islamised ethnic groups. Findings are examined in the light of ethnopolitical divides that emerge among apparently united nonmigrant groups, as peace agreements address territorial solutions. Research results are likewise discussed in relation to other tribally contoured social landscapes that carry hidden, yet fractured ethnic narratives embedded in a larger war storyline.
ON THE POSITIVITY OF RIEMANN–STIELTJES INTEGRALS
Authors: LUKKARINEN JANI , PAKKANEN MIKKO S.
Published: August 2012

We study the question whether a Riemann–Stieltjes integral of a positive continuous function with respect to a nonnegative function of bounded variation is positive.
Progress in laser acceleration of particles
Authors: Joshi Chan , Lu Wei , Sheng Zhengming
Published: August 2012

Laser acceleration of particles is currently a very active area of research in Plasma Physics, with an emphasis on acceleration of electrons and ions using short but intense laser pulses. In this special issue we access the current status of this field by inviting leading researchers all over the world to contribute their original works here. Many of these results were first presented at the recent Laser-Particle Acceleration Workshop (LPAW 2011) held in Wuzhen, China in June 2011. In addition to the laser wakefield acceleration (LWFA) of electrons (Tzoufras et al.) and laser acceleration of ions (Tsung et al.), there were exciting new proposals for a proton-driven plasma wakefield accelerator (Xia et al.) and for a dielectric-structure-based two-beam accelerator (Gai et al.) presented at this workshop, and we are very pleased to have the authors' contributions on these included here.
WHEN UNCLE TOM DIDN'T DIE: THE ANTISLAVERY POLITICS OF H. J. CONWAY'S UNCLE TOM'S CABIN
Authors: Spingarn Adena
Published: August 2012

Although Harriet Beecher Stowe's 1852 novel Uncle Tom's Cabin is widely credited with helping turn the nation against slavery and hastening the Civil War, the theatrical productions based on her novel have precisely the opposite reputation. Many scholars believe that despite the initial antislavery influence of George L. Aiken's 1852 dramatization, the Uncle Tom plays rapidly degraded, becoming more harmful than helpful to African Americans. The plays are also frequently blamed for turning Uncle Tom, the heroic Christian martyr of Stowe's novel, into the submissive race traitor his name connotes today. The “process of vulgarization” that afflicted the Uncle Tom's Cabin dramas is said to have begun almost immediately, with the 1852 premiere of H. J. Conway's adaptation. Today, Conway's version is widely designated a pro-Southern or compromise dramatization of Uncle Tom's Cabin, especially compared to Aiken's influential adaptation, which is considered to have the strongest antislavery message of the many adaptations and to be the most faithful to Stowe's novel.
NETWORKING THE WAVES: OCEAN LINERS, IMPRESARIOS, AND BROADWAY'S ATLANTIC EXPANSION
Authors: Schweitzer Marlis
Published: August 2012

InThe Great Wet Way,a humorous account of transatlantic travel, American theatre critic Alan Dale represents ocean liners as sites of transformation, frivolity, and performance. In the passage above, he ponders the peculiar metamorphosis that overtakes him whenever he crosses the Atlantic. Cut off from the hustling world of Broadway and Fifth Avenue, he loses his “real self,” becoming instead an autograph-hunting, bridge-playing, opera-glassing “ship self.” It is as though the ship has remade Dale and the social world around him (Fig. 1). Within this altered world, new sights become old sights, and eccentric clothing or mannerisms come to seem commonplace. Dale recalls seeing a young woman wearing a Panama hat covered with autographs from her fellow passengers. If the woman dared to “walk down Broadway or Fifth Avenue wearing that hideous autograph hat,” he writes, “[s]he would probably be followed by a howling and derisive mob. . . . Yet on board she was unmolested. After the first few days nobody noticed the autograph hat.”
A THEATRICAL AND TEXTUAL LABORATORY: THE CLAUDE E. ANIBAL COLLECTION OF SPANISH DRAMA
Authors: Johnson Eric J.
Published: August 2012

For generations, scholars of seventeenth- and eighteenth-century Spanish drama have been attempting to define the parameters that characterize the comedia suelta, but to date no firm consensus about the form's textual or generic qualities has been reached. Broadly defined, the term comedia suelta embraces theatrical works written in a variety of styles, including farsas (short, humorous, carnivalesque texts); sainetes (short productions or distinct portions of larger works that are normally danced and sung); eglogas (brief pastoral works, often with sad or somber overtones); entremeses (concise comedic pieces emphasizing the burlesque and the grotesque); and autos (succinct allegorical religious productions frequently tied to the celebration of the Eucharist). Other theatrical forms and subgenres current in Spanish drama of the period might also easily be classified as sueltas, depending on one's particular point of view.
Analysis of successes and failures with a tele-operated mobile robot in various modes of operation
Authors: Sanders David Adrian , Stott Ian , Robinson David , Ndzi David
Published: August 2012

The effect on failure rates of the way tele-operators interact with mobile robots is investigated. Human tele-operators attempted to move a robot through progressively more complicated environments with reducing gaps, as quickly as possible. Tele-operators used a joystick and either watched robots, while operating them, or used a computer screen to view scenes remotely. Cameras were either mounted on the robot to view the space ahead of the robot or mounted remotely so that they viewed both the environment and robot. Tele-operators completed tests both with and without sensors. Both an umbilical cable and a radio link were used.
Is the von Kármán constant affected by sediment suspension?
Authors: Castro‐Orgaz Oscar , Giráldez Juan V. , Mateos Luciano , Dey Subhasish
Published: August 2012

Is the von Kármán constant affected by sediment suspension? The presence of suspended sediment in channels and fluvial streams has been known for decades to affect turbulence transfer mechanism in sediment‐laden flows, and, therefore, the transport and fate of sediments that determine the bathymetry of natural water courses. This study explores the density stratification effects on the turbulent velocity profile and its impact on the transport of sediment. There is as yet no consensus in the scientific community on the effect of sediment suspension on the von Kármán parameter,κ. Two different theories based on the empirical log‐wake velocity profile are currently under debate: One supports a universal value ofκ = 0.41 and a strength of the wake, Π, that is affected by suspended sediment. The other suggests that both κ and Π could vary with suspended sediment. These different theories result in a conceptual problem regarding the effect of suspended sediment on κ, which has divided the research area. In this study, a new mixing length theory is proposed to describe theoretically the turbulent velocity profile. The analytical approach provides added insight defining κas a turbulent parameter which varies with the distance to the bed in sediment‐laden flows. The theory is compared with previous experimental data and simulations using ak‐εturbulence closure to the Reynolds averaged Navier Stokes equations model. The mixing length model indicates that the two contradictory theories incorporate the stratified flow effect into a different component of the log‐wake law. The results of this work show that the log‐wake fit with a reducedκ is the physically coherent approximation.
Effusive and explosive volcanism on the ultraslow‐spreading Gakkel Ridge, 85°E
Authors: Pontbriand Claire W. , Soule S. Adam , Sohn Robert A. , Humphris Susan E. , Kunz Clayton , Singh Hanumant , Nakamura Ko‐ichi , Jakobsson Martin , Shank Timothy
Published: August 2012

We use high‐definition seafloor digital imagery and multibeam bathymetric data acquired during the 2007 Arctic Gakkel Vents Expedition (AGAVE) to evaluate the volcanic characteristics of the 85°E segment of the ultraslow spreading Gakkel Ridge (9 mm yr−1full rate). Our seafloor imagery reveals that the axial valley is covered by numerous, small‐volume (order ∼1000 m3) lava flows displaying a range of ages and morphologies as well as unconsolidated volcaniclastic deposits with thicknesses up to 10 cm. The valley floor contains two prominent volcanic lineaments made up of axis‐parallel ridges and small, cratered volcanic cones. The lava flows appear to have erupted from a number of distinct source vents within the ∼12–15 km‐wide axial valley. Only a few of these flows are fresh enough to have potentially erupted during the 1999 seismic swarm at this site, and these are associated with the Oden and Loke volcanic cones. We model the widespread volcaniclastic deposits we observed on the seafloor as having been generated by the explosive discharge of CO2 that accumulated in (possibly deep) crustal melt reservoirs. The energy released during explosive discharge, combined with the buoyant rise of hot fluid, lofted fragmented clasts of rapidly cooling magma into the water column, and they subsequently settled onto the seafloor as fall deposits surrounding the source vent.
Controls of faulting and reaction kinetics on serpentinization and double Benioff zones
Authors: Iyer Karthik , Rüpke Lars H. , Phipps Morgan Jason , Grevemeyer Ingo
Published: August 2012

The subduction of partially serpentinized oceanic mantle may potentially be the key geologic process leading to the regassing of Earth's mantle and also has important consequences for subduction zone processes such as element cycling, slab deformation, and intermediate‐depth seismicity. However, little is known about the quantity of water that is retained in the slab during mantle serpentinization and the pattern of serpentinization that may occur during bending‐related faulting; an initial state that is essential for quantifying subsequent dehydration processes. We present a 2‐D reactive‐flow model simulating hydration processes in the presence of faulting at the trench outer‐rise. We find that the temperature dependence of the serpentinization rate in conjunction with outer‐rise faulting results in plate age and speed dependent patterns of hydration. Serpentinization also results in a reduction in surface heat flux toward the trench caused by advective downflow of seawater into the reaction region. Observed heat flow reductions are larger than the reduction due to the minimum‐water downflow needed for partial serpentinization, predicting that active hydrothermal vents and chemosynthetic communities should also be associated with bend‐fault serpentinization. Our model results agree with previous studies that the lower plane of double Benioff zones can be generated due to dehydration of serpentinized mantle at depth. More importantly, the depth‐dependent pattern of serpentinization including reaction kinetics predicts a separation between the two Benioff planes consistent with seismic observations.
Comparison of self‐consistent simulations with observed magnetic field and ion plasma parameters in the ring current during the 10 August 2000 magnetic storm
Authors: Chen Margaret W. , Lemon Colby L. , Guild Timothy B. , Schulz Michael , Roeder James L. , Le Guan
Published: August 2012

We assess whether magnetically and electrically self‐consistent ring current simulations can account simultaneously for in situ magnetic field and ion flux measurements in the inner magnetosphere during the large 10 August 2000 storm (min Dst = −107 nT). We use the Rice Convection Model–Equilibrium (RCM‐E) and drive it with time‐dependent magnetic field, electric field, and plasma boundary conditions that are guided by empirical and assimilative models. Comparisons of the simulated and observed magnetic field from Geostationary Operational Environmental Satellites (GOES) and observed proton differential flux spectra from Los Alamos National Laboratory (LANL) satellites are made at geosynchronous orbit (GEO). Similarly, simulated and observed magnetic field and proton density and temperature are compared along the orbit of Polar (r ∼ 1.8–9 RE) for the event. The simulated and observed magnetic field components agree reasonably well at GEO and along the orbit of Polar. However, since the effects of substorm dipolarizations are not explicitly modeled, the simulation fails to reproduce observed sawtooth fluctuations in the magnetic field. Over energies from 1 to 150 keV, the RCM‐E reproduced well the ion dispersion features in the LANL 1994‐084 ion differential flux spectra over energies at GEO and proton densities and temperatures calculated from Polar proton flux measurements. Thus, the RCM‐E simulations can account simultaneously for in situ magnetic field and ion flux measurements for the 10 August 2000 storm. This demonstrates that a self‐consistent model can produce realistic features of the storm time inner magnetosphere.
Nucleation and arrest of dynamic slip on a pressurized fault
Authors: Garagash Dmitry I. , Germanovich Leonid N.
Published: August 2012

Elevated pore pressure can lead to reactivation of slip on pre‐existing fractures and faults when the static Coulomb failure is reached locally. As the pressurized region spreads diffusively, slip can accumulate quasi‐statically (paced by the pore fluid diffusion) or dynamically. In this work, we consider a prestressed fault with a locally peaked, diffusively spreading pore pressure field to study (1) conditions leading to the escalation of slip and nucleation of dynamic rupture and (2) rupture run‐out distance before it is arrested. Nucleation appears in this model when the fault friction decreases from its peak value with slip, while arrest of dynamic propagation is imminent on aseismic faults (i.e., such that prestressτb is less than the residual fault strength τrat ambient conditions). When fluid overpressure is a small‐to‐moderate fraction of the ambient value of normal effective stress (and prestress is large enough for fault slip to be activated by overpressure), dynamic rupture always nucleates, and the nucleation length increases with decreasing prestress practically independently of the overpressure value. Transition from the ultimately unstable (τb > τr) to the ultimately stable (τb < τr) fault loading is marked by a strong increase of the nucleation length (∝1/(τb − τr)2) as τb approaches τr from above. For aseismic faults (τb < τr), no dynamic rupture is nucleated at large fluid overpressures for all but the smallest values of prestress. The largest run‐out distances of dynamic slip on aseismic faults correspond to overpressure/prestress just sufficient for slip activation. In such cases, the dynamically accumulated slip can lead to enhanced, dynamic fault weakening, resulting in a sustained dynamic rupture and generating a large earthquake. This is consistent with field observations when the largest injection‐induced seismicity occurred after fluid injection ended.
Mineralogy and chemistry of altered Icelandic basalts: Application to clay mineral detection and understanding aqueous environments on Mars
Authors: Ehlmann B. L. , Bish D. L. , Ruff S. W. , Mustard J. F.
Published: August 2012

We used a suite of techniques, including those emulating compositional data sets obtained from Mars orbit and obtainable at the Mars surface, to examine aqueous alteration of basaltic rocks from Iceland as a mineralogic and geochemical analog for Noachian environments on Mars. A sample suite was collected for laboratory measurement of (1) whole‐rock visible/near‐infrared (VNIR) reflectance and thermal infrared (TIR) emission spectra; (2) VNIR and TIR reflectance spectra of particle‐size separates derived from the bulk rock and from materials extracted from fractures/vesicles; (3) X‐ray diffraction (XRD) patterns for determination of quantitative modal mineralogy; (4) major element chemistry using flux fusion of whole‐rock powders; and (5) electron microprobe analyses of minerals in thin sections. Conclusions about aqueous alteration can be influenced by technique. For these basalts, whole‐rock chemical data showed scant evidence for chemical fractionation, but TIR, VNIR, and XRD measurements identified distinctive assemblages of hydrous silicate minerals, differing by sample. XRD provided the most complete and accurate quantitative determination of sample mineralogy. However, VNIR spectroscopy was the technique most useful for determining composition of low‐abundance smectite clays, and TIR spectroscopy was the most useful for recognizing hydrated silicates in thin surface coatings. High spatial resolution mineralogical and chemical data sets were useful for understanding the texture and distribution of alteration products and variations in fluid chemistry. No single approach provides a complete assessment of the environment of alteration, demonstrating the importance of employing multiple, synergistic mineralogical and geochemical techniques and instruments in exploration of rock strata from aqueous paleoenvironments on Mars.
A paradigm shift in understanding and quantifying the effects of forest harvesting on floods in snow environments
Authors: Green Kim C. , Alila Younes
Published: August 2012

A well‐established precept in forest hydrology is that any reduction of forest cover will always have a progressively smaller effect on floods with increasing return period. The underlying logic in snow environments is that during the largest snowmelt events the soils and vegetation canopy have little additional storage capacity and under these conditions much of the snowmelt will be converted to runoff regardless of the amount or type of vegetation cover. Here we show how this preconceived physical understanding, reinforced by the outcomes of numerous paired watershed studies, is indefensible because it is rationalized outside the flood frequency distribution framework. We conduct a meta‐analysis of postharvest data at four catchments (3–37 km2) with moderate level of harvesting (33%–40%) to demonstrate how harvesting increases the magnitude and frequency of all floods on record (19–99 years) and how such effects can increase unchecked with increasing return period as a consequence of changes to both the mean (+11% to +35%) and standard deviation (−12% to +19%) of the flood frequency distribution. We illustrate how forest harvesting has substantially increased the frequency of the largest floods in all study sites regardless of record length and this also runs counter to the prevailing wisdom in hydrological science. The dominant process responsible for these newly emerging insights is the increase in net radiation associated with the conversion from longwave‐dominated snowmelt beneath the canopy to shortwave‐dominated snowmelt in harvested areas, further amplified or mitigated by basin characteristics such as aspect distribution, elevation range, slope gradient, amount of alpine area, canopy closure, and drainage density. Investigating first order environmental controls on flood frequency distributions, a standard research method in stochastic hydrology, represents a paradigm shift in the way harvesting effects are physically explained and quantified in forest hydrology literature.
Phosphoinositide lipids and cell polarity: linking the plasma membrane to the cytocortex
Authors: Krahn Michael P. , Wodarz Andreas
Published: August 2012

Many cell types in animals and plants are polarized, which means that the cell is subdivided into functionally and structurally distinct compartments. Epithelial cells, for example, possess an apical side facing a lumen or the outside environment and a basolateral side facing adjacent epithelial cells and the basement membrane. Neurons possess distinct axonal and dendritic compartments with specific functions in sending and receiving signals. Migrating cells form a leading edge that actively engages in pathfinding and cell-substrate attachment, and a trailing edge where such attachments are abandoned. In all of these cases, both the plasma membrane and the cytocortex directly underneath the plasma membrane show differences in their molecular composition and structural organization. In this chapter we will focus on a specific type of membrane lipids, the phosphoinositides, because in polarized cells they show a polarized distribution in the plasma membrane. They furthermore influence the molecular organization of the cytocortex by recruiting specific protein binding partners which are involved in the regulation of the cytoskeleton and in signal transduction cascades that control polarity, growth and cell migration.
Continuous endocytic recycling of tight junction proteins: how and why?
Authors: Chalmers Andrew D. , Whitley Paul
Published: August 2012

Tight junctions consist of many proteins, including transmembrane and associated cytoplasmic proteins, which act to provide a barrier regulating transport across epithelial and endothelial tissues. These junctions are dynamic structures that are able to maintain barrier function during tissue remodelling and rapidly alter it in response to extracellular signals. Individual components of tight junctions also show dynamic behaviour, including migration within the junction and exchange in and out of the junctions. In addition, it is becoming clear that some tight junction proteins undergo continuous endocytosis and recycling back to the plasma membrane. Regulation of endocytic trafficking of junctional proteins may provide a way of rapidly remodelling junctions and will be the focus of this chapter.
Crucial polarity regulators in axon specification
Authors: Lalli Giovanna
Published: August 2012

Cell polarization is critical for the correct functioning of many cell types, creating functional and morphological asymmetry in response to intrinsic and extrinsic cues. Neurons are a classical example of polarized cells, as they usually extend one long axon and short branched dendrites. The formation of such distinct cellular compartments (also known as neuronal polarization) ensures the proper development and physiology of the nervous system and is controlled by a complex set of signalling pathways able to integrate multiple polarity cues. Because polarization is at the basis of neuronal development, investigating the mechanisms responsible for this process is fundamental not only to understand how the nervous system develops, but also to devise therapeutic strategies for neuroregeneration. The last two decades have seen remarkable progress in understanding the molecular mechanisms responsible for mammalian neuronal polarization, primarily using cultures of rodent hippocampal neurons. More recent efforts have started to explore the role of such mechanisms in vivo. It has become clear that neuronal polarization relies on signalling networks and feedback mechanisms co-ordinating the actin and microtubule cytoskeleton and membrane traffic. The present chapter will highlight the role of key molecules involved in neuronal polarization, such as regulators of the actin/microtubule cytoskeleton and membrane traffic, polarity complexes and small GTPases.
Renoprotective effects of a novel Nox1/4 inhibitor in a mouse model of Type 2 diabetes
Authors: Sedeek Mona , Gutsol Alex , Montezano Augusto C. , Burger Dylan , Nguyen Dinh Cat Aurelie , Kennedy Chris R. J. , Burns Kevin D. , Cooper Mark E. , Jandeleit-Dahm Karin , Page Patrick , Szyndralewiez Cedric , Heitz Freddy , Hebert Richard L. , Touyz Rhian M.
Published: August 2012

Nox (NADPH oxidase)-derived ROS (reactive oxygen species) have been implicated in the development of diabetic nephropathy. Of the Nox isoforms in the kidney, Nox4 is important because of its renal abundance. In the present study, we tested the hypothesis that GKT136901, a Nox1/4 inhibitor, prevents the development of nephropathy in db/db (diabetic) mice. Six groups of male mice (8-week-old) were studied: (i) untreated control db/m, (ii) low-dose GKT136901-treated db/m (30 mg/kg of body weight per day), (iii) high-dose GKT136901-treated db/m (90 mg/kg of body weight per day), (iv) untreated db/db; (v) low dose GKT136901-treated db/db; and (vi) high-dose GKT136901-treated db/db. GKT136901, in chow, was administered for 16 weeks. db/db mice developed diabetes and nephropathy as evidenced by hyperglycaemia, albuminuria and renal injury (mesangial expansion, tubular dystrophy and glomerulosclerosis). GKT136901 treatment had no effect on plasma glucose or BP (blood pressure) in any of the groups. Plasma and urine TBARSs (thiobarbituric acid-reacting substances) levels, markers of systemic and renal oxidative stress, respectively, were increased in diabetic mice. Renal mRNA expression of Nox4, but not of Nox2, increased, Nox1 was barely detectable in db/db. Expression of the antioxidant enzyme SOD-1 (superoxide dismutase 1) decreased in db/db mice. Renal content of fibronectin, pro-collagen, TGFβ (transforming growth factor β) and VCAM-1 (vascular cell adhesion molecule 1) and phosphorylation of ERK1/2 (extracellular-signal-regulated kinase 1/2) were augmented in db/db kidneys, with no change in p38 MAPK (mitogen-activated protein kinase) and JNK (c-Jun N-terminal kinase). Treatment reduced albuminuria, TBARS and renal ERK1/2 phosphorylation and preserved renal structure in diabetic mice. Our findings suggest a renoprotective effect of the Nox1/4 inhibitor, possibly through reduced oxidative damage and decreased ERK1/2 activation. These phenomena occur independently of improved glucose control, suggesting GKT136901-sensitive targets are involved in complications of diabetes rather than in the disease process.
Multi-energy x-ray imaging and sensing for diagnostic and control of the burning plasma
Authors: Stutman D. , Tritz K. , Finkenthal M.
Published: August 2012

New diagnostic and sensor designs are needed for future burning plasma (BP) fusion experiments, having good space and time resolution and capable of prolonged operation in the harsh BP environment. We evaluate the potential of multi-energy x-ray imaging with filtered detector arrays for BP diagnostic and control. Experimental studies show that this simple and robust technique enables measuring with good accuracy, speed, and spatial resolution the Te profile, impurity content, and MHD activity in a tokamak. Applied to the BP this diagnostic could also serve for non-magnetic sensing of the plasma position, centroid, ELM, and RWM instability. BP compatible x-ray sensors are proposed using “optical array” or “bi-cell” detectors.
The electronic spectrum of CUONg4 (Ng = Ne, Ar, Kr, Xe): New insights in the interaction of the CUO molecule with noble gas matrices
Authors: Tecmer Paweł , van Lingen Henk , Gomes André Severo Pereira , Visscher Lucas
Published: August 2012

The electronic spectrum of the CUO molecule was investigated with the IHFSCC-SD (intermediate Hamiltonian Fock-space coupled cluster with singles and doubles) method and with TD-DFT (time-dependent density functional theory) employing the PBE and PBE0 exchange–correlation functionals. The importance of both spin–orbit coupling and correlation effects on the low-lying excited-states of this molecule are analyzed and discussed. Noble gas matrix effects on the energy ordering and vibrational frequencies of the lowest electronic states of the CUO molecule were investigated with density functional theory (DFT) and TD-DFT in a supermolecular as well as a frozen density embedding (FDE) subsystem approach. This data is used to test the suitability of the FDE approach to model the influence of different matrices on the vertical electronic transitions of this molecule. The most suitable potential was chosen to perform relativistic wave function theory in density functional theory calculations to study the vertical electronic spectra of the CUO and CUONg4 with the IHFSCC-SD method.
Electronic currents and Born-Oppenheimer molecular dynamics
Authors: Patchkovskii Serguei
Published: August 2012

Born-Oppenheimer variable separation is the mainstay of studies of chemical reactivity and dynamics. A long-standing problem of this ansatz is the absence of electronic currents in a system undergoing dynamics. I analyze the physical origin of the “missing” electronic currents in Born-Oppenheimer wavefunctions. By examining the problem within the multi-state Born-Huang ansatz, I demonstrate that electronic currents arise from the first-order non-adiabatic coupling to electronically excited states. I derive two expressions for the electronic currents induced by nuclear motion. The sum-over-the-states formula, identical to the result of “complete adiabatic” treatment of Nafie [J. Chem. Phys. 79, 4950 (1983)]10.1063/1.445588 leads to a transparent and intuitive physical picture of the induced currents, but is unsuitable for practical implementation in all but the simplest systems. The equivalent expression in terms of the electronic energy derivatives is straightforward to implement numerically. I present first applications of this approach to small systems of potential chemical interest.
Population and coherence dynamics in light harvesting complex II (LH2)
Authors: Yeh Shu-Hao , Zhu Jing , Kais Sabre
Published: August 2012

The electronic excitation population and coherence dynamics in the chromophores of the photosynthetic light harvesting complex 2 (LH2) B850 ring from purple bacteria (Rhodopseudomonas acidophila) have been studied theoretically at both physiological and cryogenic temperatures. Similar to the well-studied Fenna-Matthews-Olson (FMO) protein, oscillations of the excitation population and coherence in the site basis are observed in LH2 by using a scaled hierarchical equation of motion approach. However, this oscillation time (300 fs) is much shorter compared to the FMO protein (650 fs) at cryogenic temperature. Both environment and high temperature are found to enhance the propagation speed of the exciton wave packet yet they shorten the coherence time and suppress the oscillation amplitude of coherence and the population. Our calculations show that a long-lived coherence between chromophore electronic excited states can exist in such a noisy biological environment.
Raman study of the Verwey transition in magnetite at high-pressure and low-temperature: Effect of Al doping
Authors: Gasparov L. , Shirshikova Z. , Pekarek T. M. , Blackburn J. , Struzhkin V. , Gavriliuk A. , Rueckamp R. , Berger H.
Published: August 2012

We employed Raman spectroscopy to investigate how the hydrostatic pressure affects the temperature of the Verwey transition in pure (Fe3O4) and Al-doped (Fe2.8Al0.2O4) magnetite. In both samples, pressure suppresses the transition. The Al-doped sample displays no transition above 8 GPa. We do not observe such discontinuity in a pure magnetite, which suggests that the discontinuity is doping driven. Our Clausius-Clapeyron formula based analysis of the pressure–transition temperature dependence is in excellent agreement with our data in pure magnetite. The Al doping leads to a smaller entropy change and larger volume expansion consistent with partial charge ordering at the transition.
Lateral electrical transport and photocurrent in single and multilayers of two-dimensional arrays of Si nanocrystals
Authors: Manousiadis P. , Gardelis S. , Nassiopoulou A. G.
Published: August 2012

We have investigated electrical transport and photocurrent in single and multilayers of two-dimensional arrays of silicon nanocrystals (SiNCs) suitable for photovoltaic applications. The films were grown on quartz by low pressure chemical vapor deposition of Si and subsequent thermal oxidation steps. We found that at high voltages, electrical transport is governed by space charge limited currents due to the presence of traps. At low voltages, electrical transport is ohmic. Carrier mobility, carrier concentration, and trap density in the films were extracted from the electrical measurements. Combining photocurrent and absorption measurements for the films with different SiNC sizes, we found a remarkable similarity in the photon energy dependence of the photocurrent and of the absorbed light from the SiNCs, confirming a proportionality relation between the two quantities. Also, from the combined study of electrical transport and photocurrent, minority carrier lifetimes were extracted.
Influence of Li-N and Li-F co-doping on defect-induced intrinsic ferromagnetic and photoluminescence properties of arrays of ZnO nanowires
Authors: Ghosh Shyamsundar , Gopal Khan Gobinda , Varma Shikha , Mandal Kalyan
Published: August 2012

The role of N/F co-doping on the defect-driven room-temperature d0 ferromagnetism in group-I element Li doped ZnO nanowire arrays has been investigated. The ferromagnetic signature of pristine ZnO nanowires has enhanced significantly after Li doping but the Li-N co-doping has found to be more effective in the stabilization and enhancement in room-temperature ferromagnetism in ZnO nanowires. Saturation magnetization in Li-doped ZnO nanowires found to increase from 0.63 to 2.52 emu/g and the Curie temperature rises up to 648 K when 10 at. % N is co-doped with 6 at. % Li. On the other hand, Li-F co-doping leads to exhibit much poor room-temperature ferromagnetic as well as visible luminescence properties. The valance state of the different dopants is estimated by x-ray photoelectron spectroscopy while the photoluminescence spectra indicate the gradual stabilization of Zn vacancy defects or defect complexes in presence of No acceptor states, which is found to be responsible for the enhancement of intrinsic ferromagnetism in ZnO:Li matrix. Therefore, the Li-N co-doping can be an effective parameter to stabilize, enhance, and tune zinc vacancy-induced room-temperature d0 ferromagnetism in ZnO nanowires, which can be an exciting approach to prepare new class of spintronic materials.
Basic data of ions in He-air mixtures for fluid modeling of low temperature plasma jets
Authors: Yousfi M. , Hennad A. , Benhenni M. , Eichwald O. , Merbahi N.
Published: August 2012

The basic ion data such as interaction potential parameters, elastic and inelastic collision cross sections, transport coefficients (reduced mobility and diffusion coefficients) and reaction coefficients have been analysed and determined for the case of He+, N2+, and O2+ in He-dry air mixtures. The ion transport and reaction coefficients have been determined from an optimized Monte Carlo simulation using calculated elastic and experimentally fitted inelastic collision cross sections. The elastic momentum transfer cross sections have been calculated from a semi-classical JWKB (Jeffreys Wentzel Kramers Brillouin) approximation based on a (6-4) rigid core interaction potential model. The inelastic cross sections have been fitted using the measured reaction coefficients, such as, for instance, the non resonant charge transfer coefficients. The cross section sets involving elastic and inelastic processes were then validated using either the measured reduced mobility whenever available in the literature or the zero-field mobility calculated from Satoh’s relation, and potential parameters available in the literature. From the sets of elastic and inelastic collision cross sections thus obtained for the first time for He+/N2, He+/O2, N2+/He, and O2+/He systems, the ion transport and reaction coefficients were calculated in the pure gases over a wide range of the density reduced electric field E/N. Then, from the present cross section and other literature sets, the ion mobility and the longitudinal and transverse diffusion coefficients were calculated for different concentrations of air in He in the case of He+, N2+, O2+, and also O− ions.
Magnetic viscosity, hysteresis reptation, and their relationship with adjacent track interference in advanced perpendicular recording media
Authors: Srinivasan Kumar , Roddick Eric
Published: August 2012

The role of exchange interactions and thermal relaxation in advanced three-layer exchange-coupled composite perpendicular recording media with graded anisotropy was investigated through studies on magnetic viscosity, magnetic hysteresis reptation, and spin-stand adjacent track interference. For this purpose, thickness series in the NiW seed and the three magnetic layers were made and studied. For each sample, both magnetic viscosity and reptation were evaluated using a magnetometer over a series of initial magnetic states. Magnetic viscosity, which is the change in the magnetization of the sample with time, showed a distinct second-order dependence on a logarithmic time-scale. In general, viscosity appeared to be more strongly influenced by exchange-coupling interactions in the media than the thermal stability. Magnetic reptation, which is the change in the magnetization when the external field was repeatedly cycled between a nonzero field and zero field, i.e., remanence, showed two types of distinct reptation phenomena—field reptation and remanence reptation—depending on whether the magnetic state was evaluated with the external field present or removed, respectively. Both field and remanence reptation showed a second-order logarithmic dependence on the number of cycles. A comparison of viscosity and field reptation revealed a correlation, indicating that the origin of field reptation in perpendicular recording media can be associated with viscosity. Such a correlation could not be established between viscosity and remanence reptation. Spin-stand signal amplitude change of written tracks, due to adjacent track interference, also followed a second-order logarithmic dependence on the number of adjacent writes. When compared appropriately, the signal amplitude change showed an excellent correlation with remanence reptation across all media samples. This suggests that adjacent track interference in magnetic recording can be associated with remanence reptation evaluated using a magnetometer, despite their vast difference in time-scales. Moreover, this correlation was observed irrespective of the thermal stability of the media, which corroborates the hypothesis that in composite media, exchange interaction effects have a more dominant role than thermal relaxation effects in influencing switchability vis-à-vis adjacent track interference. In consequence, remanence reptation can be a useful technique to study the interplay of exchange and thermal effects in magnetic media.
An enhancement behavior of coercivity near TC in ferromagnetic films with uniaxial magnetic anisotropy
Authors: Dho Joonghoe
Published: August 2012

The temperature dependence of coercivity was investigated in CrO2 and La0.7Sr0.3MnO3 films with and without uniaxial magnetic anisotropy. When the magnetic field was applied along the uniaxial magnetic anisotropy axis, the coercivities of the CrO2 and La0.7Sr0.3MnO3 films showed remarkable enhancement behaviors near ferromagnetic transition temperature (TC). In contrast, CrO2 and La0.7Sr0.3MnO3 films without uniaxial magnetic anisotropy did not exhibit such an enhancement behavior. The temperature dependence of coercivity HC(T) for an aligned Stoner-Wohlfarth ferromagnet was theoretically studied based on a modified model of previously reported ones by He [Phys. Rev. B 75, 184424 (2007)] and Grimsditch [Phys. Rev. Lett. 90, 257201 (2003)]. Experimentally observed enhancement of coercivity near TC could be explained by an effect of a distribution of the local ordering temperatures ρ(TB) for magnetic grains. The qualitative behavior of HC(T) was investigated for three different types of uniaxial anisotropies: (i) magnetocrystalline anisotropy, (ii) strain-induced anisotropy, and (iii) shape anisotropy.
Experience Produces the Atypicality Bias in Object Perception
Authors: Kantner Justin , Tanaka James W
Published: August 2012

When a morph face is produced with equal physical contributions from a typical parent face and an atypical parent face, the morph is judged to be more similar to the atypical parent. This discontinuity between physical and perceptual distance relationships, called the “atypicality bias” (Tanaka et al 1998, Cognition68 199–220), has also been demonstrated with non-face objects (birds and cars; Tanaka and Corneille 2007 Perception & Psychophysics69 619–627). We tested whether the atypicality bias can be induced for a novel set of artificial objects. Two categories of “blob” stimuli were generated, each composed of typical and atypical members. Morphs averaged from typical and atypical parent exemplars were used to test the presence of an atypicality bias before and after participants were familiarized with blob items. In experiment 1, participants were trained to discriminate between the two blob categories. An atypicality bias was evident after, but not prior to, category training. In experiment 2, participants rated the pleasantness of the blobs instead of learning to categorize them; an atypicality bias was present only after the ratings task. This finding suggests that relatively passive exposure to exemplars is sufficient to influence perceptions of similarity, and that the atypicality bias is a manifestation of this influence.