bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal-insulator transition in low dimensional La0.75Sr0.25VO3 thin films
Authors: Dao Tran M. , Mondal Partha S. , Takamura Y. , Arenholz E. , Lee Jaichan
Published: September 2011

We report on the metal-insulator transition that occurs as a function of film thickness in ultrathin La0.75Sr0.25VO3 films. The metal-insulator transition displays a critical thickness of 5 unit cell. Above the critical thickness, metallic films exhibit a temperature driven metal-insulator transition with weak localization behavior. With decreasing film thickness, oxygen octahedron rotation in the films increases, causing enhanced electron-electron correlation. The electron-electron correlations in ultrathin films induce the transition from metal to insulator in addition to Anderson localization.
III-V-on-nothing metal-oxide-semiconductor field-effect transistors enabled by top-down nanowire release process: Experiment and simulation
Authors: Gu J. J. , Koybasi O. , Wu Y. Q. , Ye P. D.
Published: September 2011

III-V-on-nothing (III-VON) metal-oxide-semiconductor field-effect transistors (MOSFETs) are experimentally demonstrated with In0.53Ga0.47As as channel and atomic layer deposited Al2O3 as gate dielectric. A hydrochloric acid based release process has been developed to create an air gap beneath the InGaAs channel layer, forming the nanowire channel with width down to 40 nm. III-VON MOSFETs with channel lengths down to 50 nm are fabricated and show promising improvement in drain-induced barrier lowering, due to suppressed short-channel effects. The top-down processing technique provides a viable pathway towards fully gate-all-around III-V MOSFETs.
Polariton laser based on a ZnO photonic crystal slab
Authors: Solnyshkov D. D. , Weiss T. , Malpuech G. , Gippius N. A.
Published: September 2011

We propose a scheme of a ZnO room-temperature polariton laser based on a photonic crystal slab. We predict a very low threshold density for optical pumping: 5 × 1016 cm−3. We have studied the threshold dependence on the parameters of the system, such as detuning. The main advantage of photonic-crystal-based polariton laser is expected to be the simplicity of production.
Secondary Ion Mass Spectrometry of Macromolecules Loading in Individual Polyelectrolyte Multilayer Microcapsules
Authors: Yakovlev Nikolai L. , Kiryukhin Maxim V. , Antipina Maria N. , Susanto Theo T. , Ravi Sethuraman , Adithyavairavan Murali , Sukhorukov Gleb B.
Published: September 2011

The control over the amount of a payload in polyelectrolyte multilayer microcapsules is of particular importance for several applications, such as transportation and delivery of drugs, enzymes, and other (bio)active materials. In this work, secondary ion mass spectrometry is applied to measure the content of peroxidase in individual capsules. The distribution of a payload among the capsules in a batch is analyzed for different loading routines. Absorption in porous CaCO3 demonstrates lower enzyme content with a standard deviation of 40 % on average. pH-Controlled post-loading gives two to three times higher content and a standard deviation of 20–25 %. The decrease of pH upon post-loading increases the encapsulation efficiency.
Epitaxy of Porous and Photocatalytically Active TiO2 Films at 50°C
Authors: Goh Gregory K. L. , Chan Kelvin Y. S. , Huang Gao S. , Tay Qui L.
Published: September 2011

Epitaxial anatase TiO2 thin films were grown on (001) oriented SrTiO3 single crystal substrates by liquid phase deposition at 50°C. The film consisted of nanosized crystallites and exhibited a significant void fraction of 31 %. This contributed to the cracking of thicker films due to the generation of capillary stresses in the nanosized pores during drying. This porosity also comes in useful during the photodegradation of a methylene blue dye by an as-grown film.
Aggregation-Induced Emission and Biological Application of Tetraphenylethene Luminogens
Authors: Hong Yuning , Lam Jacky Wing Yip , Chen Sijie , Tang Ben Zhong
Published: September 2011

Tetraphenylethene derivatives [Ph(PhCH=CHPhR)C=C(PhCH=CHPhR)Ph, R=H, CN, NO2, NPh2] with green, yellow-green, and orange emission colours were designed and synthesized. These molecules are practically non-emissive in their dilute solutions but emit intensely as nanoaggregates in poor solvents, demonstrating a novel phenomenon of aggregation-induced emission. Their blended films with poly(methyl methacrylate) also display bright emissions. Restriction of intramolecular motion in the condensed phase may be responsible for such unusual behaviour. Multilayer electroluminescence devices with a configuration of indium tin oxide/N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine/emitter/tris(8-hydroxyquinolinolato)aluminum (Alq3)/LiF/Al were constructed, which gave green light with a maximum luminance and current efficiency of 12930 cd cm–2 and 3.04 cd A–1 respectively. The tetraphenylethenes can serve as excellent cell staining agents for selectively illuminating the cytoplasm and vesicles of living cells.
Self-Assembly of Poly(L-glutamate)-block-poly(2-(diethylamino)ethyl methacrylate) in Aqueous Solutions
Authors: Leung Angela M. H. , Ng Vanessa , Ho Yoon K. , Zhou Lihan , Too Heng P. , Tam Kam C.
Published: September 2011

The self-assembly and gene delivery applications of poly(l-glutamate)-block-poly(2-(diethylamino)ethyl methacrylate) (PLG18-b-PDEAEMA37) were investigated. Owing to the functional groups on the polymer, an amine and a carboxylic acid group, the self-assembly process is dependent on the solution pH, where the critical micelle concentration was determined to be 61 and 320 μg mL–1 at high and low pH, respectively. The block copolymer forms positively charged vesicles at low pH with a hydrodynamic radius of 90 nm and negatively charged vesicles at high pH with a hydrodynamic radius of 50 nm. At the isoelectric point of 4.9, PLG-b-PDEAEMA was found to form larger micellar aggregates with a hydrodynamic radius of 180 nm because of the presence of both positive and negative charges. The complexation between PLG-b-PDEAEMA and DNA was studied at physiological pH as well as at low and high pH. DNA is condensed most effectively at pH 3, at an N/P ratio of 5, whereas at pH 7 and 10, an N/P ratio of 20 is required. However, in-vitro studies at physiological pH using neuroblastoma cells did not show substantial gene expression.
History as Literature
Authors: Meisami Julie Scott
Published: September 2011

Confronted with the task of writing a chapter on “History as Literature” for the volume on Persian historiography in the newHistory of Persian Literature,I found myself asking, “What does this title mean? And what might it imply?“ In medieval Islamicate societies, “history” (Arabicta˒rīkh,Persiantārīkh)referred both to a specific discipline and to works dealing with the objects of that discipline. If, as written works, histories may be broadly classed as “literature” (for which neither Arabic or Persian had a corresponding term until the modern period), this might suggest that historians placed style over substance, or/and that history is “imaginative writing” and may, as such, contain an element of “fiction.” Indeed, as I shall note below, recent research on Arabic historiography (which poses somewhat different problems, in the main, than does Persian) has argued that many of the “historical” accounts which appear therein are, in fact, “fiction” passed off as history.
The Amazon, the Sources of the Nile, and Tabriz: Nadir Mirza's Tārīkh Va jughrāfi-yi dār al-salṭana-yi Tabrīz and the Local Historiography of Tabriz and Azerbaijan
Authors: Werner Christoph
Published: September 2011

Neither this article nor the work of Nadir Mirza is primarily concerned with the Amazon or with the quest for the Nile sources. But a certain amusing curiosity aside, the fact that Nadir Mirza touches on subjects like this in a historical work on Tabriz is a clear hint that we are leaving the traditional boundaries of Iranian local historiography—and not only in the metaphorical sense.

To place Nadir Mirza's history of Tabriz in a more general context is a rather difficult task. Such a context is provided of course by the longstanding tradition of Persian local and regional historiography—as treated in the present collection of articles—and particularly in connection with the late development of this genre in the nineteenth century. Local works of historiography from the Qajar period quite often defy attempts at classification according to medieval categories such as chronicles, biographical dictionaries, or adab-literature.
Long-Term Memory for Spatial and Temporal Mental Models Includes Construction Processes and Model Structure
Authors: Baguley Thom , Payne Stephen J.
Published: September 2011

There is a strong case that people construct and manipulate mental models in working memory but relatively little evidence that mental models are preserved in long-term memory. Instead people may remember an episodic construction trace: a record of the operations used to construct a mental model (Payne, 1993). Experiment 1 investigated memory for determinate spatial descriptions (which describe a single configuration of objects) and indeterminate spatial descriptions (which describe two equally plausible configurations). Recognition performance was impaired when the overlap between the episodic construction trace of a description at learning and at test was disrupted by reordering the sentences within a description. Participants were better at remembering the gist of determinate descriptions than that of indeterminate descriptions. For indeterminate descriptions, provided differences in gist recognition were controlled, participants showed better memory for the original description. Experiment 2 showed a similar pattern of results with temporal descriptions. A third experiment manipulated the similarity between foils in the recognition test and the original descriptions to provide further evidence for both episodic construction trace and remembered mental models. In combination, these results favour a hybrid account of memory for mental models, which includes information about both construction processes and model structure.
Perceptual Priming is not a Necessary Consequence of Semantic Classification of Pictures
Authors: Bruce Vicki , Carson Derek , Mike Burton A. , Ellis Andrew W.
Published: September 2011

Four experiments investigated how repetition priming of object recognition is affected by the task performed in the prime and test phases. In Experiment 1 object recognition was tested using both vocal naming and two different semantic decision tasks (whether or not objects were manufactured, and whether or not they would be found inside the house). Some aspects of the data were inconsistent with contemporary models of object recognition. Specifically, object priming was eliminated with some combinations of prime and test tasks, and there was no evidence of perceptual (as opposed to conceptual or response) priming in either semantic classification task, even though perceptual identification of the objects is required for at least one of these tasks. Experiment 2 showed that even when perceptual demands were increased by brief presentation, the inside task showed no perceptual priming. Experiment 3 showed that the inside task did not appear to be based on conceptual priming either, as it was not primed significantly when the prime decisions were made to object labels. Experiment 4 showed that visual sensitivity could be restored to the inside task following practice on the task, supporting the suggestion that a critical factor is whether the semantic category is preformed or must be computed. The results show that the visual representational processes revealed by object priming depend crucially on the task chosen.
The Development of the Use of Long-Term Knowledge to Assist Short-Term Recall
Authors: Turner Judy E. , Henry Lucy A. , Smith Philip T.
Published: September 2011

The influence of item familiarity upon memory span was examined in adults and children aged 5, 7, and 10 years by comparing the recall of words and nonwords. Using a probed recall task, both item recall and position recall were tested. The effect of familiarity upon item recall was found to develop with age, from no effects in the 5-year-olds to significant effects in the older children and adults. By contrast, no effect of familiarity was found at any age when recall of position was required. Dissociations between word length effects and familiarity effects supported the conclusion that the familiarity effect does not result from rehearsal. Several explanations for the source of the familiarity effect were examined, and the familiarity effect was attributed to a strategic redintegration or reconstruction process, which is necessary for item recall but not for position recall.
Implicit Sequence Learning with Competing Explicit Cues
Authors: Jiménez Luis , Méndez Cástor
Published: September 2011

Previous research has shown that the expression of implicit sequence learning is eliminated in a choice reaction time task when an explicit cue allows participants to accurately predict the next stimulus (Cleeremans, 1997), but that two contingencies predicting the same outcome can be learned and expressed simultaneously when both of them remain implicit (Jiménez & Méndez, 1999). Two experiments tested the hypothesis that it is the deliberate use of explicit knowledge that produces the inhibitory effects over the expression of implicit sequence learning. However, the results of these experiments do not support this hypothesis, rather showing that implicit learning is acquired and expressed regardless of the influence of explicit knowledge. These results are interpreted as reinforcing the thesis about the automatic nature of both the acquisition and the expression of implicit sequence learning. The contradictory results reported by Cleeremans are attributed to a floor effect derived from the use of a special type of explicit cue.
Algorithmic Solution of Arithmetic Problems and Operands-Answer Associations in Long-Term Memory
Authors: Thevenot Catherine , Barrouillet Pierre , Fayol Michel
Published: September 2011

Many developmental models of arithmetic problem solving assume that any algorithmic solution of a given problem results in an association of the two operands and the answer in memory (Logan & Klapp, 1991; Siegler, 1996). In this experiment, adults had to perform either an operation or a comparison on the same pairs of two-digit numbers and then a recognition task. It is shown that unlike comparisons, the algorithmic solution of operations impairs the recognition of operands in adults. Thus, the postulate of a necessary and automatic storage of operands-answer associations in memory when young children solve additions by algorithmic strategies needs to be qualified.
Task-Switching Costs, Stroop-Costs, and Executive Control: A Correlational Study
Authors: Ward Geoff , Roberts Maxwell J. , Phillips Louise H.
Published: September 2011

Three correlational studies investigated the relationship between the time costs associated with Stroop stimuli (Stroop-costs) with the time costs associated with task-switching (switch-costs) obtained from colour-word stimuli and digit stimuli. In all studies, large and significant positive correlations were found between different measures of switch-costs. However, only small (and sometimes non-significant) correlations were obtained between the different measures of Stroop-costs and between measures of Stroop-costs and measures of switch-costs. The results are taken as evidence for the existence of some common or shared specialized mechanisms involved in taskswitching, which are different from those used to overcome Stroop interference.
Does Negative Priming Reflect Inhibitory Mechanisms? A Review and Integration of Conflicting Views
Authors: Tipper Steven P.
Published: September 2011

Negative priming has traditionally been viewed as a reflection of an inhibitory mechanism of attention. However, recent accounts have suggested that negative priming does not reflect inhibitory mechanisms. Rather, slowed reaction times on negative priming trials are either due to retrieval of incompatible response tags or of mismatching perceptual information, or due to extra processes needed to distinguish past from present information. In contrast, it is proposed that there is no firm evidence to discount inhibition models. In fact, although retrieval processes can be implicated in negative priming effects, understanding of these requires consideration of the inhibitory processes involved in selecting information for goal-directed behaviour.
Development of Memory for Pattern and Path: Further Evidence for the Fractionation of Visuo-Spatial Memory
Authors: Pickering Susan J. , Gathercole Susan E. , Hall Melanie , Lloyd Simon A.
Published: September 2011

Evidence from a number of sources now suggests that the visuo-spatial sketchpad (VSSP) of working memory may be composed of two subsystems: one for maintaining visual information and the other for spatial information. In this paper we present three experiments that examine this fractionation using a developmental approach. In Experiment 1, 5-, 8-, and 10-year old children were presented with a visuo-spatial working memory task (the matrices task) with two presentation formats (static and dynamic). A developmental dissociation in performance was found for the static and dynamic conditions of both tasks, suggesting that the activation of separable subsystems of the VSSP is dependent upon a static/dynamic distinction in information content rather than a visual/spatial one. A highly similar pattern of performance was found for a mazes task with static and dynamic formats. However, one strategic activity, the use of simple verbal recoding, may also have been responsible for the observed pattern of performance in the matrices task. In Experiments 2 and 3 this was investigated using concurrent articulatory suppression. No evidence to support this notion was found, and it is therefore proposed that static and dynamic visuo-spatial information is maintained in working memory by separable subcomponents of the VSSP.
Syllabic Organization and Deafness: Orthographic Structure or Letter Frequency in Reading?
Authors: Olson Andrew C. , Nickerson Jane F.
Published: September 2011

For hearing people, structure given to orthographic information may be influenced by phonological structures that develop with experience of spoken language. In this study we examine whether profoundly deaf individuals structure orthographic representation differently. We ask “Would deaf students who are advanced readers show effects of syllable structure despite their altered experience of spoken language, or would they, because of reduced influence from speech, organize their orthographic knowledge according to groupings defined by letter frequency?” We used a task introduced by Prinzmetal (Prinzmetal, Treiman, & Rho, 1986) in which participants were asked to judge the colour of letters in briefly presented words. As with hearing participants, the number of errors made by deaf participants was influenced by syllable structure (Prinzmetal et al., 1986; Rapp, 1992). This effect could not be accounted for by letter frequency. Furthermore, there was no correlation between the strength of syllable effects and residual speech or hearing. Our results support the view that the syllable is a unit of linguistic organization that is abstract enough to apply to both spoken and written language.
Neuropsychological Evidence for Case-Specific Reading: Multi-Letter Units in Visual Word Recognition
Authors: Hall Deborah A. , Humphreys Glyn W. , Cooper Adam C. G.
Published: September 2011

We describe a patient (GK) who shows symptoms associated with Balint's syndrome and attentional dyslexia. GK was able to read words, but not nonwords. He also made many misidentification and mislocation errors when reporting letters in words, suggesting that his word-naming ability did not depend upon preserved position-coded, letter identification. We show that GK was able to read lower-case words better than upper-case words, but upper-case abbreviations better than lower-case abbreviations. Spacing the letters in abbreviations disrupted identification, as did mixing the case of letters within words. These data cannot be explained in terms of letter-based reading or preserved holistic word recognition. We propose that GK was sensitive to the visual familiarity of adjacent letter forms.
Laplace transform of products of Bessel functions: A visitation of earlier formulas
Authors: Kausel Eduardo , Irfan Baig Mirza
Published: September 2011

This note deals with the Laplace transforms of integrands of the form

x
λ

J
α

(

a
x

)

J
β

(

b
x

)

{x^\lambda }{J_\alpha }\left ( {ax} \right ){J_\beta }\left ( {bx} \right )

, which are found in numerous fields of application. Specifically, we provide herein both a correction and a supplement to the list of integrals given in 1997 by Hanson and Puja, who in turn extended the formulas of Eason, Noble and Sneddon of 1956. The paper concludes with an extensive tabulation for particular cases and range of parameters.
Familiar taste induces higher dendritic levels of activity-regulated cytoskeleton-associated protein in the insular cortex than a novel one
Authors: Morin Jean-Pascal , Quiroz Cesar , Mendoza-Viveros Lucia , Ramirez-Amaya Victor , Bermudez-Rattoni Federico
Published: September 2011

The immediate early gene (IEG) Arc is known to play an important role in synaptic plasticity; its protein is locally translated in the dendrites where it has been involved in several types of plasticity mechanisms. Because of its tight coupling with neuronal activity, Arc has been widely used as a tool to tag behaviorally activated networks. However, studies examining the modulation of Arc expression during and after learning have yielded somewhat contradictory results. Although some have reported that higher levels of Arc were induced by initial acquisition of a task rather than by reinstating a learned behavior, others have failed to observe such habituation of Arc transcription. Moreover, most of these studies have focused on the mRNA and, surprisingly, relatively little is known about how learning can affect Arc protein expression levels. Here we used taste recognition memory and examined Arc protein expression in the insular cortex of rats at distinct times during taste memory formation. Interestingly, we found that more Arc protein was induced by a familiar rather than by a novel taste. Moreover, this increase was inhibited by post-trial intrahippocampal anisomycin injections, a treatment known to inhibit safe-taste memory consolidation. In addition, confocal microscopy analysis of immunofluorescence stained tissue revealed that the proportion of IC neurons expressing Arc was the same in animals exposed to novel and familiar taste, but Arc immunoreactivity in dendrites was dramatically higher in rats exposed to the familiar taste. These results provide novel insights on how experience affects cortical plasticity.
Estimation of left ventricular function using a novel acoustic‐based device
Authors: Radzievsky Naira , Papyan Surik , Kushnir Igal , Gat Merav , Kushnir Alon , Sagie Alex , Agmon Yoram
Published: September 2011

Eur J Clin Invest 2012; 42 (4): 402–410

Background  We examined the feasibility of estimating left ventricular ejection fraction (LVEF) by a novel acoustic‐based device [vibration response imaging (VRI); Deep Breeze].

Methods  One hundred and forty‐one subjects (117 patients and 24 healthy volunteers; age 55 ± 15 years, 82% men) were examined by both VRI and echocardiography. LVEF was determined by echocardiography (echo‐LVEF) using the biplane Simpson’s method. Low‐frequency acoustic signals (10–70 Hz) were recorded by VRI from the left posterior thorax by a matrix of 36 microphones during 8 s of breath holding, and an electrocardiogram was recorded simultaneously. The acoustic signals were processed digitally, and an algorithm designed to estimate LVEF was developed (VRI‐LVEF), based on a combination of multiple acoustic (systolic and diastolic acoustic signals, beat‐to‐beat variability of acoustic signals and propagation of acoustic signals throughout the matrix), electrocardiographic and clinical parameters.

Results  Mean echo‐LVEF was 51 ± 15% (range, 11–76%). Echo‐LVEF was reduced (< 50%) in 55 subjects (39%) and severely reduced (< 35%) in 28 subjects (20%). VRI‐LVEF calculated by a multivariate algorithm correlated significantly with echo‐LVEF (R2 = 0·59; P < 0·001). VRI‐LVEF accurately predicted the presence of reduced (< 50%) or severely reduced (< 35%) echo‐LVEF, with sensitivities of 84% and 82%, specificities of 86% and 91%, positive predictive values of 79% and 70% and negative predictive values of 89% and 95%, respectively.

Conclusions  LVEF can be estimated using a novel acoustic‐based device. This device may assist in triage of patients according to LVEF prior to definitive assessment of LVEF by echocardiography.
Proinflammatory cytokines during the initial phase of oral mucositis in patients with acute lymphoblastic leukaemia
Authors: MORALES‐ROJAS THAIS , VIERA NINOSKA , MORÓN‐MEDINA ALEJANDRA , ÁLVAREZ CARMEN JULIA , ÁLVAREZ ALEJANDRA
Published: September 2011

International Journal of Paediatric Dentistry 2012; 22: 191–196

Objective.  The aim of the study was to compare the production of proinflammatory cytokines during the initial phase of mucositis in patients with acute lymphoblastic leukaemia.

Methods.  A randomized, controlled clinical trial was carried out. Cytokine levels were determined in blood and saliva using ELISA, three times after the administration of methotrexate and only once in the control group.

Results.  Comparison of the results showed significant differences for IL‐6 and TNF‐α in blood and IL‐6 in saliva.

Conclusion.  It would seem that 96 h is an ideal time for determining the parameters evaluated both in blood and in saliva.
Cdv‐based cell division and cell cycle organization in the thaumarchaeon Nitrosopumilus maritimus
Authors: Pelve Erik A. , Lindås Ann‐Christin , Martens‐Habbena Willm , de la Torre José R. , Stahl David A. , Bernander Rolf
Published: September 2011

Cell division is mediated by different mechanisms in different evolutionary lineages. While bacteria and euryarchaea utilize an FtsZ‐based mechanism, most crenarchaea divide using the Cdv system, related to the eukaryotic ESCRT‐III machinery. Intriguingly, thaumarchaeal genomes encode both FtsZ and Cdv protein homologues, raising the question of their division mode. Here, we provide evidence indicating that Cdv is the primary division system in the thaumarchaeon Nitrosopumilus maritimus. We also show that the cell cycle is differently organized as compared to hyperthermophilic crenarchaea, with a longer pre‐replication phase and a shorter post‐replication stage. In particular, the time required for chromosome replication is remarkably extensive, 15–18 h, indicating a low replication rate. Further, replication did not continue to termination in a significant fraction of N. maritimus cell populations following substrate depletion. Both the low replication speed and the propensity for replication arrest are likely to represent adaptations to extremely oligotrophic environments. The results demonstrate that thaumarchaea, crenarchaea and euryarchaea display differences not only regarding phylogenetic affiliations and gene content, but also in fundamental cellular and physiological characteristics. The findings also have implications for evolutionary issues concerning the last archaeal common ancestor and the relationship between archaea and eukaryotes.
An SMC ATPase mutant disrupts chromosome segregation in Caulobacter
Authors: Schwartz Monica A. , Shapiro Lucy
Published: September 2011

Accurate replication and segregation of the bacterial genome are essential for cell cycle progression. We have identified a single amino acid substitution in the Caulobacter structural maintenance of chromosomes (SMC) protein that disrupts chromosome segregation and cell division. The E1076Q point mutation in the SMC ATPase domain caused a dominant‐negative phenotype in which DNA replication was able to proceed, but duplicated parS centromeres, normally found at opposite cell poles, remained at one pole. The cellular positions of other chromosomal loci were in the wild‐type order relative to the parS centromere, but chromosomes remained unsegregated and appeared to be stacked upon one another. Purified SMC‐E1076Q was deficient in ATP hydrolysis and exhibited abnormally stable binding to DNA. We propose that SMC spuriously links the duplicated chromosome immediately after passage of the replication fork. In wild‐type cells, ATP hydrolysis opens the SMC dimer, freeing one chromosome to segregate to the opposite pole. The loss of ATP hydrolysis causes the SMC‐E1076Q dimer to remain bound to both chromosomes, inhibiting segregation.
Bacillus anthracis virulence regulator AtxA: oligomeric state, function and CO2‐signalling
Authors: Hammerstrom Troy G. , Roh Jung Hyeob , Nikonowicz Edward P. , Koehler Theresa M.
Published: September 2011

AtxA, a unique regulatory protein of unknown molecular function, positively controls expression of the major virulence genes of Bacillus anthracis. The 475 amino acid sequence of AtxA reveals DNA binding motifs and regions similar to proteins associated with the phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS). We used strains producing native and functional epitope‐tagged AtxA proteins to examine protein–protein interactions in cell lysates and in solutions of purified protein. Co‐affinity purification, non‐denaturing polyacrylamide gel electrophoresis and bis(maleimido)hexane (BMH) cross‐linking experiments revealed AtxA homo‐multimers. Dimers were the most abundant species. BMH cross‐links available cysteines within 13 Å. To localize interaction sites, six AtxA mutants containing distinct Cys→Ser substitutions were tested for multimerization and cross‐linking. All mutants multimerized, but one mutation, C402S, prevented cross‐linking. Thus, BMH uses C402 to make the inter‐molecular bond between AtxA proteins, but C402 is not required for protein–protein interaction. C402 is in a region bearing amino acid similarity to Enzyme IIB proteins of the PTS. The AtxA EIIB motif may function in protein oligomerization. Finally, cultures grown with elevated CO2/bicarbonate exhibited increased AtxA dimer/monomer ratios and increased AtxA activity, relative to cultures grown without added CO2/bicarbonate, suggesting that this host‐associated signal enhances AtxA function by shifting the dimer/monomer equilibrium towards the dimeric state.
The phytochelatin transporters AtABCC1 and AtABCC2 mediate tolerance to cadmium and mercury
Authors: Park Jiyoung , Song Won‐Yong , Ko Donghwi , Eom Yujin , Hansen Thomas H. , Schiller Michaela , Lee Tai Gyu , Martinoia Enrico , Lee Youngsook
Published: September 2011

Heavy metals such as cadmium (Cd) and mercury (Hg) are toxic pollutants that are detrimental to living organisms. Plants employ a two‐step mechanism to detoxify toxic ions. First, phytochelatins bind to the toxic ion, and then the metal–phytochelatin complex is sequestered in the vacuole. Two ABCC‐type transporters, AtABCC1 and AtABCC2, that play a key role in arsenic detoxification, have recently been identified in Arabidopsis thaliana. However, it is unclear whether these transporters are also implicated in phytochelatin‐dependent detoxification of other heavy metals such as Cd(II) and Hg(II). Here, we show that atabcc1 single or atabcc1 atabcc2 double knockout mutants exhibit a hypersensitive phenotype in the presence of Cd(II) and Hg(II). Microscopic analysis using a Cd‐sensitive probe revealed that Cd is mostly located in the cytosol of protoplasts of the double mutant, whereas it occurs mainly in the vacuole of wild‐type cells. This suggests that the two ABCC transporters are important for vacuolar sequestration of Cd. Heterologous expression of the transporters in Saccharomyces cerevisiae confirmed their role in heavy metal tolerance. Over‐expression of AtABCC1 in Arabidopsis resulted in enhanced Cd(II) tolerance and accumulation. Together, these results demonstrate that AtABCC1 and AtABCC2 are important vacuolar transporters that confer tolerance to cadmium and mercury, in addition to their role in arsenic detoxification. These transporters provide useful tools for genetic engineering of plants with enhanced metal tolerance and accumulation, which are desirable characteristics for phytoremediation.
Thrombocytopenia at birth in neonates with red cell alloimmune haemolytic disease
Authors: Rath M. E. A. , Smits‐Wintjens V. E. H. J. , Oepkes D. , van Zwet E. W. , van Kamp I. L. , Brand A. , Walther F. J. , Lopriore E.
Published: September 2011

Objective  To evaluate the incidence and severity of and risk factors for thrombocytopenia at birth in neonates with red cell alloimmunization.

Study design  All neonates with haemolytic disease of the foetus/newborn (HDFN) due to red cell alloimmunization admitted to our centre between January 2000 and September 2010 were included in this retrospective study. We measured platelet counts at birth and determined the incidence of thrombocytopenia (platelet count < 150 × 109/l) and severe thrombocytopenia (platelet count < 50 × 109/l). Risk factors for thrombocytopenia at birth were evaluated.

Results  Thrombocytopenia was present in 26% (94/362) of included neonates with HDFN at birth. Severe thrombocytopenia was found in 6% (20/362) of neonates. Three risk factors were found to be independently associated with thrombocytopenia at birth: treatment with intrauterine red cell transfusion (IUT) (OR 3·32, 95% CI 1·67–6·60, P = 0·001), small for gestational age (SGA) below the 10th percentile (OR 3·32, 95% CI 1·25–8·80, P = 0·016) and lower gestational age at birth (OR 1·22/week, 95% CI 1·02–1·44, P = 0·025).

Conclusions  Thrombocytopenia at birth occurs in 26% of neonates with HDFN due to red cell alloimmunization and is independently associated with IUT treatment, SGA and lower gestational age at birth.
Adhesive interaction between peripheral blood mononuclear cells and activated platelets in the presence of anti‐human leukocyte antigen Class I alloantibody causes production of IL‐1β and IL‐8
Authors: Takahashi D. , Fujihara M. , Azuma H. , Wakamoto S. , Sato S. , Kato T. , Ikeda H.
Published: September 2011

Background:  Activated platelets form heterogeneous aggregates of platelets and monocytes, which are involved in a variety of inflammatory disorders. Some anti‐human leukocyte antigen (HLA) Class I antibodies have been shown to activate platelets.

Materials and Methods:  Human leukocyte antigen‐A2‐positive or HLA‐A2‐negative platelets were incubated with HLA‐A2‐negative peripheral blood mononuclear cells (PBMNCs) in the presence of anti‐HLA‐A2 serum at 37°C. The binding of platelets to monocytes was analysed by flow cytometry. The levels of IL‐1 β and IL‐8 in the culture supernatant were determined by ELISA.

Results:  Anti‐HLA‐A2 serum increased the formation of aggregates between monocytes and HLA‐A2‐positive platelets, but not HLA‐A2‐negative platelets, in a dose‐dependent manner. Antiserum also increased the number of platelets bound to monocytes in a time‐dependent manner. The addition of anti‐P‐selectin glycoprotein ligand (PSGL‐1) mAb almost completely inhibited the formation of platelet–monocyte aggregates as well as the number of platelets bound to monocytes. When HLA‐A2‐positive or HLA‐A2‐negative platelets were incubated with HLA‐A2‐negative PBMNCs in the presence of anti‐HLA‐A2, the level of IL‐1β and IL‐8 in the supernatant of coculture was significantly higher in HLA‐A2‐positive platelets than in HLA‐A2‐negative platelets. The addition of anti‐PSGL‐1 mAb partially but significantly inhibited the production of both IL‐1β and IL‐8.

Conclusions:  The activation of platelets with anti‐HLA Class I alloantibody caused the formation of platelet–monocyte aggregates, followed by the production of IL‐1β and IL‐8, in a cognate antigen–antibody manner. The adhesive interaction of P‐selectin and PSGL‐1 at least partially contributed to these phenomena.
Detection and Identification of Three ‘Candidatus Phytoplasma’ Species in Picea spp. Trees in Poland
Authors: Kamińska Maria , Berniak Hanna
Published: September 2011

We report the detection of phytoplasmas in Picea abies, Picea glauca and Picea pungens trees with witches’ brooms and other growth abnormalities and also in symptomless trees. Phytoplasmas were detected in c. 25% of the tested plants by polymerase chain reaction using phytoplasma universal P1/P7 followed by R16F2n/R16R2 primer pairs. The phytoplasmas were classified as members of the phylogenetic groups: 16SrI, ‘Ca. Phytoplasma asteris’; 16SrIII, X‐disease phytoplasma group; and 16SrXXI, ‘Ca. Phytoplasma pini’.
Long‐term outcomes of living kidney donors: A single centre experience of 29 years
Authors: CHU KWOK‐HONG , POON CLARA KA‐YAN , LAM CHUNG‐MAN , CHEUK AU , YIM KA‐FAI , LEE WILLIAM , TANG HON‐LOK , CHAN HILDA WAI‐HAN , FUNG KA‐SHUN , TONG KWOK‐LUNG
Published: September 2011

Aim:  Living kidney donation provides the best source of kidney graft. The mortality and morbidity rates are small but the long‐term effects have not been studied. This is a report on our 29‐year experience of living kidney donation.

Methods:  All living donors were arranged to have follow‐ups. Defaulters were traced via a territory‐wide computer system.

Results:  A total of 149 living kidney donor operations were performed. 136/149 records were available. 41 defaulted follow‐up. One donor died of multiple myeloma. The male to female ratio was 1.00 to 1.52. Mean age at donation was 33.94 ± 9.66 years. Mean follow‐up duration was 160.39 ± 87.96 months. Hypertension was diagnosed in 27 donors (19.9%). 22 donors (17.3%) had stage 3 chronic kidney disease (CKD). Glomerular filtration rate (GFR) dropped from 90.95 ± 15.62 mL/min per 1.73 m2 at time 0 to 66.29 ± 12.06 mL/min per 1.73 m2 at 2 years. GFR improved subsequently and remained stable for 25 years. Age at donation was associated with hypertension (HT) in univariate and multivariate analyses. HT was not associated with sex or GFRs over time. Using binary logistic regression, age at donation was associated with the development of stage 3 CKD and GFR before donation was associated with lower CKD risk. In multivariate analysis, only age at donation was associated with CKD. Other co‐morbidities included: hyperlipidaemia 16/136, diabetes mellitus 6/136, cardiovascular event 1/136, stroke 1/136 and cancer 5/136.

Conclusions:  Living kidney donors had reductions in GFR post uninephrectomy with subsequent improvement. A significant proportion developed HT and stage 3 CKD. Age at donation was a strong determinant of development of HT and stage 3 CKD.
CAPSULE ENDOSCOPY FINDINGS IN PATIENTS WITH OCCULT OR OVERT BLEEDING OLDER THAN 80 YEARS
Authors: TSIBOURIS PANAGIOTIS , KALANTZIS CHRISSOSTOMOS , APOSTOLOPOULOS PERIKLIS , ALEXANDRAKIS GEORGIOS , MAVROGIANNI PANAGIOTA , KALANTZIS NIKOLAOS
Published: September 2011

Background:  Overt and occult bleeding are the main indications for a wireless capsule endoscopy (WCE) study of the small bowel. Most published studies omit patients aged over 80.

Aim:  To determine whether WCE is feasible in patients with overt or occult bleeding over age 80 and to define the spectrum of small bowel pathologies in this age group.

Patients and Methods:  In a retrospective non‐randomized tertiary care study, 60 patients at least 80 years or older (aged group) and 120 matched patients aged <80 years (younger group) with overt or occult bleeding (including iron deficiency anaemia) and no significant gastroscopic or colonoscopic findings underwent WCE.

Results:  Of the 180 patients, 46 (77%) patients in the aged group and 97 (81%) in the younger group successfully completed small bowel study (P = 0.51). There was no difference in gastric transit time and small bowel passing time between the two groups. More patients in the aged group (48 cases, 80%) than the younger group (56 cases, 47%) presented with small bowel angiodysplasias (P < 0.0001). Nevertheless, there was no difference between the two groups concerning ulcerative and neoplastic lesions. No patient presented with capsule impaction, but more patients in the aged group (35 cases, 58%) than in the younger group (10 cases, 8%) found the study difficult and tiresome (P < 0.001). Preparation validation was poor in 34% of small bowel lumen in the aged group and 19% in the younger group (P = 0.03).

Conclusion:  WCE is feasible, although rather tiresome, in patients over the age of 80. Though the vast majority of patients older than 80 presented with angiodysplasias, there were no differences between the aged and younger groups in the presence of ulcerative lesions and polyps or tumors.
Local anesthetics and their adjuncts
Authors: Mazoit Jean‐Xavier
Published: September 2011

Local anesthetics (LA) block propagation of impulses along nerve fibers by inactivation of voltage‐gated sodium channels, which initiate action potentials (1). They act on the cytosolic side of phospholipid membranes. Two main chemical compounds are used, amino esters and amino amides. Amino esters are degraded by pseudocholinesterases in plasma. Amino amides are metabolized exclusively by the liver. Only amide LAs will be considered in this article.
A novel platelet‐activating factor acetylhydrolase discovered in a metagenome from the earthworm‐associated microbial community
Authors: Navarro‐Fernández José , Nechitaylo Taras Y. , Guerrero José A. , Golyshina Olga V. , García‐Carmona Francisco , Sánchez‐Ferrer Álvaro , Golyshin Peter N.
Published: September 2011

Metagenomics is an emerging field for mining the bioresources for new biomolecules for potential application in biotechnology and biomedicine. In the present study, a novel acetylhydrolase (Est13) was detected during the function‐based screening of a metagenomic library established from the DNA extracted from the cellulose‐depleting microbial community set up with an earthworm cast. Analysis showed that Est13 exhibited some similarities with a human and parasite platelet‐activating factor acetylhydrolase (PAF‐AH) belonging to the SGNH hydrolase superfamily. Biochemical characterization of the purified recombinant enzyme using substrates common for hydrolases of this superfamily demonstrated that Est13 hydrolysed p‐nitrophenyl acetate quite efficiently, with a kcat/KM value of 3209 mM−1 s−1. The Est13 showed highest activity at pH 8.0 and 40°C, conditions in which it is relatively stable compared with known PAF‐AHs. In vitro functional analysis of the platelet‐activating factor hydrolysis showed a dose‐ and time‐dependent inhibition of platelet aggregation in the range of 2–4 µM, making this enzyme a potential candidate for biomedical applications.
The impact of the two‐week wait referral pathway on rectal cancer survival
Authors: Currie A. C. , Evans J. , Smith N. J. , Brown G. , Abulafi A. M. , Swift R. I.
Published: September 2011

Aim  The aim of this study was to compare the outcome of patients with rectal cancer referred through the two‐week wait (TWW) system with those identified by routine referral pathways (non‐TWW).

Method  A prospective study was carried out of 125 consecutive patients diagnosed with rectal cancer between January 2000 and December 2005 (6 years) in one district general hospital. Data were recorded prospectively in a local clinicopathological registry. The patients were divided into two groups: group 1 (TWW) and group 2 (routine referral pathway).

Results  Fifty‐two (41%) of the 125 patients were diagnosed through the TWW (group 1). There was no significant difference in patient demographics, including baseline tumour characteristics, between the two groups. There was no difference in preoperative or postoperative T stage between the two groups (P = 0.63). There was no significant difference in circumferential margin positivity (five of 52 in group 1 vs four of 73 in group 2; P = 0.52) or local recurrence rates (P = 0.37). The 5‐year all‐cause mortality was 49% for group 1 and 52% for group 2 (P = 0.3). The overall disease‐free survival was similar in the two groups (1521 days for group 1 vs 1591 days for group 1, P = 0.29).

Conclusion  Referral under the TWW strategy does not translate into improved survival in rectal cancer.
Onchocerca lupicausing ocular disease in two cats
Authors: Labelle Amber L. , Daniels Joshua B. , Dix Michael , Labelle Philippe
Published: September 2011

Although canine ocular onchocerciasis has been well described as an emerging pathogen of dogs in Europe and North America over the past 20 years, there are no previous reports of feline ocular onchocerciasis. This report details the clinical, histopathologic, and molecular diagnosis of two domestic short hair cats residing in the United States infected withOnchocerca lupicausing episcleritis and orbital cellulitis. The results of this report suggest thatO. lupiis a newly recognized disease of domestic cats.
The effect of dorzolamide 2% on circadian intraocular pressure in cats with primary congenital glaucoma
Authors: Sigle Kelly J. , Camaño‐Garcia Gabriel , Carriquiry Alicia L. , Betts Daniel M. , Kuehn Markus H. , McLellan Gillian J.
Published: September 2011

Objective To determine the extent of fluctuation in circadian intraocular pressure (IOP) and the efficacy of topical dorzolamide 2% q 8 h in lowering IOP and blunting circadian fluctuation in IOP in glaucomatous cats.

Animals studied Seven adult cats with primary congenital glaucoma (PCG).

Procedures Measurements of IOP and pupil diameter were obtained for both eyes (OU) of each cat q 4 h for 12 days. Cats were housed in a laboratory animal facility with a 12‐h light:dark cycle. Baseline values were established for 2 days. For the next 5 days, placebo (1.4% polyvinyl alcohol) was administered OU q 8 h. Dorzolamide 2% was then administered OU q 8 h for a further 5 days. A multivariate mixed linear model was fitted to the data, with parameters estimated from a Bayesian perspective. The 4 amtime point was selected as the reference for the purposes of comparisons.

Results Estimated mean IOP for the reference time point pre‐treatment was symmetric (about 33 mmHg OU). In all cats, IOP was significantly lower during the diurnal phase, relative to the 4 ammeasurements, with highest IOP observed 2–6 h after the onset of the dark phase. Circadian fluctuations in IOP were dampened during the treatment period. There was a significant decrease in IOP in all cats during the dorzolamide treatment period (estimated mean for the treatment period reference = 17.9 mmHg OU).

Conclusions Topical dorzolamide 2% q 8 h is effective in reducing IOP and IOP fluctuation in cats with PCG.