bluuebunny/crossref_metadata_2025 huggingface dataset:
Early wheeze as reported by mothers and lung function in 4‐year‐olds. Prospective cohort study in Krakow
Authors: Jedrychowski Wieslaw , Maugeri Umberto , Perera Frederica P. , Mroz Elzbieta , Klimaszewska‐Rembiasz Maria , Flak Elzbieta , Edwards Susan , Majewska Renata , Sowa Agata
Published: July 2010

The purpose of the study was to check the hypothesis that early wheezing as reported by mothers would be associated with reduced lung function in 4‐year olds. Study participants were recruited prenatally, as part of a prospective cohort study on the respiratory health of young children exposed to various ambient air pollutants. After delivery, infants were followed over 4 years and the interviewers visited participants at their home to record respiratory symptoms every 3 months in the child's first 2 years of life and every 6 months in the 3rd and 4th years. In the 4th year of follow‐up, children were invited for standard lung function testing by spirometry quantified by forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), and forced expiratory volume in 0.5 sec (FEV0.5) levels. Out of 258 children attending spirometry testing 139 performed at least two acceptable exhalation efforts. Cohort children with acceptable spirometric measurements did not differ with respect to wheezing experience and exposure characteristics from those without. The study shows that episodic wheeze was reported in 28.1% of 4‐year olds, 6.5% had transient wheeze, and 4.3% had recurrent wheeze. There was an increased frequency of wheezing symptoms and their duration in transient and recurrent wheezers. Adjusted multivariable regression models for gender and height showed that children who reported more than two episodes of wheezing at any point over the follow‐up had FVC values lower by 120.5 ml (P = 0.016) and FEV1 values lower by 98.3 ml (P = 0.034) compared to those who did not report any wheezing; children experiencing more than 10 wheezing days by age 4 showed FVC deficit of 87.4 ml (P = 0.034) and FEV1 values of 65.7 ml (P = 0.066). The ratios of FEV1/FVC%, and FEV0.5/FVC% were neither associated with wheezing episodes nor wheezing days. In recurrent wheezers, lung function decrement amounted to 207 ml of FVC, 175 ml of FEV1, and 104 ml of FEV0.5. In conclusion, our findings show that wheezing experience during early postnatal life may be associated with lung function deficit of restrictive character in preschool children and detailed history of wheeze in early postnatal life, even though not physician‐confirmed, may help define the high risk group of children for poor lung function testing. Pediatr. Pulmonol. 2010; 45:919–926. © 2010 Wiley‐Liss, Inc.
Substituent Effects on Thermodynamic and Detonation Properties of Polynitrobenzenes
Authors: Liao Xin , Ju Xue‐Hai , Zhao Feng‐Qi , Yi Jian‐Hua
Published: July 2010

Density functional theory (DFT) calculations were performed for a series of polynitrobenzene derivatives. Some nitrobenzenes with amino groups attached were also investigated as a benchmark or as a precursor. Heats of formation (HOF) were evaluated. The isodesmic reactions used for the prediction of HOFs are of permutation type in terms of the substituents. The HOFs increase non‐additively with increasing number of nitro groups. The attachment of the amino groups to polynitrobenzenes dramatically decreases the HOF. The HOF of hexanitrobenzene (HNB) is 344.05 kJ mol−1 at the B3LYP/6‐311+G** level. This value is much larger than that of the widely used 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB), which engenders HNB a large chemical energy of detonation. The strengths of the group interactions were analyzed according to the disproportionation energy. The nearest‐neighbor interactions in polynitrobenzenes are in the range of 27.20–55.90 kJ mol−1. The energy barrier for the internal rotation of nitro group in nitrobenzene is 24.6 kJ mol−1. However, the energy barrier for the internal rotation of 2‐position nitro group of 1,2,3‐trinitrobenzene is as large as 216.3 kJ mol−1. The chemical energies of detonation for polynitrobenzenes with three or more nitro groups are over 6000 J g−1. Pentanitroaniline and HNB have good performances in terms of detonation velocity and pressure.
Biological responses to glyphosate drift from aerial application in non‐glyphosate‐resistant corn
Authors: Reddy Krishna N , Ding Wei , Zablotowicz Robert M , Thomson Steven J , Huang Yanbo , Krutz L Jason
Published: July 2010

BACKGROUND: Glyphosate drift from aerial application onto susceptible crops is inevitable, yet the biological responses to glyphosate drift in crops are not well characterized. The objectives of this research were to determine the effects of glyphosate drift from a single aerial application (18.3 m swath, 866 g AE ha−1) on corn injury, chlorophyll content, shikimate level, plant height and shoot dry weight in non‐glyphosate‐resistant (non‐GR) corn.

RESULTS: One week after application (WAA), corn was killed at 3 m from the edge of the spray swath, with injury decreasing to 18% at 35.4 m downwind. Chlorophyll content decreased from 78% at 6 m to 22% at 15.8 m, and it was unaffected beyond 25.6 m at 1 WAA. Shikimate accumulation in corn decreased from 349% at 0 m to 93% at 15.8 m, and shikimate levels were unaffected beyond 25.6 m downwind. Plant height and shoot dry weight decreased gradually with increasing distance. At a distance of 35.4 m, corn height was reduced by 14% and shoot dry weight by 10% at 3 WAA.

CONCLUSIONS: Corn injury and other biological responses point to the same conclusion, that is, injury from glyphosate aerial drift is highest at the edge of the spray swath and decreases gradually with distance. The LD50 (the lethal distance that drift must travel to cause a 50% reduction in biological response) ranged from 12 to 26 m among the biological parameters when wind speed was 11.2 km h−1 and using a complement of CP‐09 spray nozzles on spray aircraft. Published 2010 by John Wiley & Sons, Ltd.
Maximum likelihood estimation of error covariances in ensemble‐based filters and its application to a coupled atmosphere–ocean model
Authors: Ueno Genta , Higuchi Tomoyuki , Kagimoto Takashi , Hirose Naoki
Published: July 2010

We propose a method for estimating optimal error covariances in the context of sequential assimilation, including the case where both the system equation and the observation equation are nonlinear. When the system equation is nonlinear, ensemble‐based filtering methods such as the ensemble Kalman filter (EnKF) are widely used to deal directly with the nonlinearity. The present approach for covariance optimization is a maximum likelihood estimation carried out by approximating the likelihood with the ensemble mean. Specifically, the likelihood is approximated as the sample mean of the likelihood of each member of the ensemble. To evaluate the sampling error of the proposed ensemble‐approximated likelihood, we construct a method for examining the statistical significance using the bootstrap method without extra ensemble computation. We apply the proposed methods to an EnKF experiment where TOPEX/POSEIDON altimetry observations are assimilated into an intermediate coupled model, which is nonlinear, and estimate the optimal parameters that specify the covariances of the system noise and observation noise. Using these optimal covariance parameters, we examine the estimates by the EnKF and the ensemble Kalman smoother (EnKS). The effect of smoothing decreases by 1/e approximately one year after the filtering step. One of the properties of the smoothed estimate is that westerly wind anomalies over the western Pacific are not reproduced around the period of an El Niño event, while those over the central Pacific are strengthened. From additional experiments, we find that (1) the westerly winds in the western Pacific are phenomena outside of the coupled model and are not necessary to model El Niño, (2) the model El Niño is maintained by the westerlies over the central Pacific, and (3) the modelled evolution process of the sea‐surface temperature (SST) requires improvement to reproduce the westerly winds over the western Pacific. Copyright © 2010 Royal Meteorological Society
Coexistence of Vapor–Liquid–Solid and Vapor–Solid–Solid Growth Modes in Pd‐Assisted InAs Nanowires
Authors: Heun Stefan , Radha Boya , Ercolani Daniele , Kulkarni Giridhar U. , Rossi Francesca , Grillo Vincenzo , Salviati Giancarlo , Beltram Fabio , Sorba Lucia
Published: July 2010

During the growth of InAs nanowires from Pd catalyst particles on InAs(111)A substrates, two distinct classes of nanowires are observed with smooth or zigzagged sidewalls. It is shown that this is related to a bimodal distribution of the wire‐tip diameter: above a critical diameter wires grow with smooth sidewalls, and below with zigzagged morphology. Transmission electron microscopy analysis shows that the catalyst particles at the tip of zigzagged wires are smooth and have a higher aspect ratio than those at the tip of smooth wires. Zigzagged wires grow from liquid particles in the vapor–liquid–solid (VLS) mode whereas the smooth ones grow from solid particles in the vapor–solid–solid (VSS) mode.
Gain-of-Function of Olig Transcription Factors Enhances Oligodendrogenesis and Myelination
Authors: Maire Cécile L. , Wegener Amélie , Kerninon Christophe , Nait Oumesmar Brahim
Published: July 2010

The basic helix-loop-helix transcription factors Olig1 and Olig2 are required for oligodendrocyte specification and differentiation during central nervous system (CNS) development but the effects of overexpression of these factors in murine development are not well understood. To test whether Olig1 and Olig2 may reprogram CNS stem/progenitors toward an oligodendroglial fate for myelination, we generated transgenic mice with doxycycline (Dox)-inducible expression of Olig1 or Olig2 in nestin-expressing stem/progenitor cells of the CNS. Overexpression of Olig1 or Olig2 from E8.5 to E12.5 was sufficient to promote the generation of Platelet-Derived Growth Factor Receptor alpha + oligodendrocyte precursors (OPCs) in the spinal cord. We also demonstrated that overexpression of Olig2, but not Olig1, enhanced the stem/progenitor cell proliferation and generation of motoneuron precursors and inhibited the development of V3 interneurons. In the postnatal brain, Dox-inducible expression of Olig2 but not Olig1 in nestin+ stem/progenitors of the subventricular zone increased the generation of OPCs that migrated and differentiated into mature oligodendrocytes in the corpus callosum, cortex and olfactory bulb, leading to increased and precocious myelination. Altogether, our data indicate that Olig2 is a potential therapeutic target to enhance myelination and remyelination in the CNS.
Climate change adaptation and peace
Authors: Tänzler Dennis , Maas Achim , Carius Alexander
Published: July 2010

Climate change may have dramatic consequences for several regions. Most vulnerable are fragile countries with limited capacities to adapt. Without timely action, the stresses induced by climate change may increase the risk of violent conflict. Designing and implementing adaptation strategies is becoming imperative to mitigate conflict potentials and prevent escalation. This article will discuss existing national and international approaches with focus on the UNFCCC process. It will be emphasized that a purely technical understanding of adaptation is insufficient to cope with the socio‐political consequences of climate change. Indeed, adaptation may even contribute to conflict potentials if ill‐designed. Thus, it is necessary to develop conflict‐sensitive approaches complemented by internationally supported capacity development measures. © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Vulnerability and Adaptation to Climate Change > Values‐Based Approach to Vulnerability and Adaptation

Vulnerability and Adaptation to Climate Change > Institutions for Adaptation
Targeting the epigenome: effects of epigenetic treatment strategies on genomic stability in healthy human cells
Authors: Purrucker Jan C. , Mahlknecht Ulrich
Published: July 2010

Epigenetic treatment concepts have long been ascribed as being tumour-selective. Over the last decade, it has become evident that epigenetic mechanisms are essential for a wide range of intracellular functions in healthy cells as well. Evaluation of possible side-effects and their underlying mechanisms in healthy human cells is necessary in order to improve not only patient safety, but also to support future drug development. Since epigenetic regulation directly interacts with genomic and chromosomal packaging density, increasing genomic instability may be a result subsequent to drug-induced epigenetic modifications. This review highlights past and current research efforts on the influence of epigenetic modification on genomic stability in healthy human cells.
The Core Model
Authors: Dodd A.
Published: July 2010

The core model, K, is a generalization of Gödel's constructible universe of set theory; K is used to produce 'fine structural' results of a less restrictive kind. This book aims to introduce the core model to those with a basic knowledge of axiomatic set theory. The covering lemma for K is the main technical result but other applications are also considered. The author gives a full exposition of general fine structure and of iterated ultrapowers and concludes the work with a short section on the difficulties encountered in constructing more general core models using 'extenders'.
Clinical MR Spectroscopy
Authors: Barker Peter B. , Bizzi Alberto , De Stefano Nicola , Gullapalli Rao , Lin Doris D. M.
Published: July 2010

In vivo magnetic resonance spectrosopy (MRS) is increasingly being used in the clinical setting, particularly for neurological disorders. Clinical MR Spectroscopy – Techniques and Applications explains both the underlying physical principles of MRS and provides a perceptive review of clinical MRS applications. Topics covered include an introduction to MRS physics, information content of spectra from different organ systems, spectral analysis methods, recommended protocols and localization techniques, and normal age- and region-related spectral variations in the brain. Clinical applications in the brain are discussed for brain tumors, hypoxic and ischemic injury, infectious, inflammatory and demyelinating diseases, epilepsy, neurodegenerative disorders, trauma and metabolic diseases. Outside of the brain, techniques and applications are discussed for MRS in the musculosketal system, breast and prostate. Written by leading MRS experts, this is an invaluable guide for anyone interested in in vivo MRS, including radiologists, neurologists, neurosurgeons, oncologists and medical researchers.
The first description of eggs in the male reproductive system of Physaloptera bispiculata (Nematoda: Spiruroidaea)
Authors: Oliveira-Menezes A. , Lanfredi-Rangel A. , Lanfredi R.M.
Published: July 2010

Physaloptera bispiculata (Nematoda: Spiruroidaea) is a parasite of Nectomys squamipes (Rodentia: Cricetidae), a water rat that only occurs in Brazil. Naturally infected rodents were captured in the municipality of Rio Bonito, Rio de Janeiro, Brazil. Adult P. bispiculata worms were collected, prepared and analysed by light and scanning electron microscopy. Under scanning electron microscopy, several eggs were seen glued by cement to the cloacal aperture. Light microscopy revealed that some male worms had an uncountable number of embryonated eggs in the ejaculatory duct, cloaca and also in the posterior portion of the intestine. The probable explanation is that the eggs developing in the female uterus are pumped by the female or sucked by the male to the cloacal opening and from this point to the intestine and ejaculatory duct. The male probably does not have the ability to expel the eggs and for this reason a large number were found in these organs. On the other hand, this could be an important adaptation for the parasite, i.e. male worms expelled by the host can carry a large number of eggs and spread them to intermediate hosts when ingested by these hosts. As far as we know this is the first record of a physalopterid nematode harbouring eggs in the cloacal region, ejaculatory duct or intestine.
Institutional Proliferation and the Global Refugee Regime
Authors: Betts Alexander
Published: July 2010

This article explores the impact of institutional proliferation on the politics of refugee protection. The refugee regime mainly comprises the 1951 Convention on the Status of Refugees and the Office of the United Nations High Commissioner for Refugees (UNHCR). Recently, however, new parallel and overlapping institutions have emerged in relation to two previously unregulated areas: internally displaced persons (IDPs) and international migration. This institutional proliferation has affected both state strategy and IO strategy in relation to refugee protection. It has enabled Northern states to engage in regime shifting. They have used the new institutions to prevent refugees reaching their territory, thereby avoiding incurring UN rules on refugee protection, and transferring burdens to Southern states. The resulting reduction in international cooperation in the refugee regime has contributed to UNHCR fundamentally redefining its strategy in order to become more relevant to Northern states. In particular, it has pursued states into the migration and IDP regimes into which they have shifted through a combination of stretching its mandate, engaging in the politics of the emerging regimes, and issue-linkage. The article's analysis draws attention to the potentially significant relationship between institutional proliferation and IO adaptation and change.
Understanding gangs as armed groups
Authors: Hazen Jennifer M.
Published: July 2010

Gangs have long been considered a source of violence and insecurity, but they are increasingly identified as a cause of instability and a threat to the state. Yet gangs operate mainly in non-conflict settings, raising questions about whether applying a conflict lens to understand gangs is appropriate. Marked differences appear between armed groups and gangs when considering concepts of ungoverned spaces, the state, violence, and sustainability. Few gangs reach the threshold of posing a direct challenge to the state; this makes comparisons with other armed groups difficult and suggests the need for a more specific analytical lens.
Higher‐energy plasma ions found near the termination shock: Analyses of Voyager 2 data in the heliosheath and in the outer heliosphere
Authors: Intriligator Devrie S. , Intriligator James , Miller W. David , Webber William R. , Decker Robert B.
Published: July 2010

We have found in the Voyager 2 (V2) plasma science data in the heliosheath (HS) near the termination shock (TS) high‐energy ions (HEIs) in addition to the bulk plasma convective flow ions. The HEI detections temporally coincide with increased V2 plasma wave subsystem (PWS) activity in “event A” of Gurnett and Kurth (2008). Maxwellian fits to HEI detections indicate the HEIs are moving radially anti‐Sunward with a proton speed of 600 km/s, a density of 10−4 cm−3, and a thermal speed of 10 km/s. The heliosheath bulk convective protons have a speed of 204 km/s, a density of 0.0029 cm−3, and a thermal speed of 26.7 km/s. The HEI flux and ram pressure are approximately 10% and 30% of those of the bulk HS flow. Since the HEI speed is both close to twice the solar wind speed and independent of the heliosheath bulk plasma speed, the HEIs may be detections of pickup protons formed in the solar wind and convected through the TS. The HEIs also are reminiscent of the pickup protons upstream of the Mars bow shock where their energy also was independent of the bulk plasma speed and attributed to multiple reflections off the Mars bow shock. Gurnett and Kurth's (2008) event A enhanced PWS activity may be generated by a two‐stream instability from the interaction of these HEIs with the heliosheath bulk plasma ions. We present our findings, discuss their implications, and also present alternative interpretations.
Thrombin-activated human platelets acutely generate oxidized docosahexaenoic-acid-containing phospholipids via 12-lipoxygenase
Authors: Morgan Lloyd T. , Thomas Christopher P. , Kühn Hartmut , O'Donnell Valerie B.
Published: July 2010

Arachidonate-containing oxidized phospholipids are acutely generated by 12-LOX (12-lipoxygenase) in agonist-activated platelets. In the present study, formation of structurally related lipids by oxidation of DHA (docosahexaenoic acid)-containing phospholipids is demonstrated using lipidomic approaches. Precursor scanning reverse-phase LC (liquid chromatography)–MS/MS (tandem MS) identified a new family of lipids that comprise phospholipid-esterified HDOHE (hydroxydocosahexaenoic acid). Two diacyl and two plasmalogen PEs (phosphatidylethanolamines) containing predominantly the 14-HDOHE positional isomer (18:0p/14-HDOHE-PE, 18:0a/14-HDOHE-PE, 16:0a/14-HDOHE-PE and 16:0p/14-HDOHE-PE) were structurally characterized using MS/MS and by comparison with biogenic standards. An involvement of 12-LOX was indicated as purified recombinant human 12-LOX also generated the 14-HDOHE isomer from DHA. Pharmacological studies using inhibitors and recombinant platelet 12-LOX indicate that they form via esterification of newly formed non-esterified HDOHE. HDOHE-PEs formed at significant rates (2–4 ng/4×107 cells) within 2–180 min of thrombin stimulation, and their formation was blocked by calcium chelation. In summary, a new family of oxidized phospholipid was identified in thrombin-activated human platelets.
Differential Stimulation of Somatostatin but Not Neuropeptide Y Gene Expression by Quinolinic Acid in Cultured Cortical Neurons
Authors: Patel Y. C. , Liu J.‐L. , Warszynska A. , Kent G. , Papachristou D. N. , Patel S. C.
Published: July 2010

Abstract: Somatostatin (SS) and neuropeptide Y (NPY) are coproduced in a subpopulation of neurons that are selectively resistant to NMDA neurotoxicity. We have previously reported that quinolinic acid (QUIN), an NMDA receptor agonist, augments SS mRNA in cultured fetal rat cortical neurons. This study examines coregulation of SS and NPY by QUIN and NMDA in cultured cortical neurons and compares the effects of these agents with those of forskolin and phorbol 12‐myristate 13‐acetate (PMA), known to activate SS and NPY gene transcription by protein kinase A‐ and protein kinase C‐dependent mechanisms. In addition, transcriptional regulation of the SS gene was investigated by acute transfection of cortical cultures with an SS promoter‐chloramphenicol acetyltransferase (CAT) construct. QUIN and NMDA displayed dose‐dependent fourfold augmentation of levels of mRNA for SS but not for NPY. In contrast, forskolin and PMA increased both SS and NPY mRNA levels. QUIN‐ and NMDA‐mediated induction of SS mRNA was blocked by the NMDA receptor antagonist (−)‐2‐amino‐5‐phosphonovaleric acid and displayed regional brain specificity because it was not observed in fetal hypothalamic cell cultures. In time course studies, the effects of QUIN/NMDA on SS mRNA occurred after a latency of 8 h, indicating a delayed effect. Cortical cells transfected with pSS‐750 CAT showed three‐ to fourfold stimulation of CAT activity with forskolin but not by QUIN or NMDA. These data reveal a dose‐dependent, tissue‐specific, NMDA receptor‐mediated stimulation of SS but not NPY mRNA. Such stimulation of SS gene expression does not require activation of the protein kinase A or protein kinase C signaling pathways, is not transcriptionally mediated, and is likely posttranscriptional, as also suggested by the delay in SS mRNA induction.
Relationships of Dopamine, Cortical Oxygen Pressure, and Hydroxyl Radicals in Brain of Newborn Piglets During Hypoxia and Posthypoxic Recovery
Authors: Olano Marta , Song Dekun , Murphy Stephanie , Wilson David F. , Pastuszko Anna
Published: July 2010

Abstract: The present study describes the relationships of extracellular striatal dopamine, cortical oxygen pressure, and striatal hydroxyl radicals in brain of newborn piglets during hypoxia and posthypoxic reoxygenation. Hypoxia was induced by reducing the fraction of inspired oxygen (FiO2) from 22% (control) to 7% for 1 h. The FiO2 was then returned to the control value and measurements were continued for 2 h. Cerebral oxygen pressure was measured by the oxygen dependent quenching of phosphorescence and extracellular levels of dopamine, 3,4‐dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and hydroxy radicals in the striatum were determined by in vivo microdialysis. Hypoxia decreased the cortical oxygen pressure from 47 ± 2 to 9 ± 1.3 torr (p < 0.001); the levels of extracellular dopamine in the striatum increased to 16,000 ± 3,270% of control (p < 0.01), whereas the levels of DOPAC and HVA decreased to 25.3 ± 6% (p < 0.001) and 36 ± 5% (p < 0.01) of control, respectively. Compared with control, the hydroxyl radical levels at each time point were not significantly increased during hypoxia, although the sum of the measured values was significantly increased (p < 0.05). During the first 5 min after FiO2 was returned to 22%, the cortical oxygen pressure increased to control values and stayed at this level for the remainder of the measurement period. The extracellular level of dopamine declined to values not statistically different from control during 40 min of reoxygenation. During the first 10 min of reoxygenation, DOPAC and HVA further decreased and then began to slowly increase. By 70 min of reoxygenation, the values were not significantly different from control. Hydroxyl radicals were above control during the entire period of reoxygenation, with maximal values observed after 100 min of reoxygenation. This increase was largely abolished by injecting the animals with α‐methyl‐p‐tyrosine 5 h before hypoxia, a procedure that depleted the brain of dopamine. Our results suggest that oxidation of striatal dopamine during posthypoxic reoxygenation is at least partly responsible for the observed increase in striatal level of hydroxyl radicals that may exacerbate posthypoxic cerebral injury.
Thermally induced surface instabilities in polymer light emitting diodes
Authors: Akande Wali O. , Akogwu Onobu , Tong Tiffany , Soboyejo Wole
Published: July 2010

The role of thermal gradients and their attendant mechanical stresses in the overall stability of organic electronic devices has been elucidated through the occurrence of spiral shaped blisters that develop on the surface of suitably biased polymer light emitting diodes. A model based on the spontaneous disordering (or ordering) of polymeric thin film systems has been used to explain the formation and growth of these blisters. The model is shown to provide insights into how thermal stresses affect the overall stability of organic electronic devices. The implications of the results are then discussed for the design of flexible organic electronic devices.
Fast scanning cavity offset lock for laser frequency drift stabilization
Authors: Seymour-Smith Nicolas , Blythe Peter , Keller Matthias , Lange Wolfgang
Published: July 2010

We have implemented a compact setup for long-term laser frequency stabilization. Light from a stable reference laser and several slave lasers is coupled into a confocal Fabry–Pérot resonator. By stabilizing the position of the transmission peaks of the slave lasers relative to successive peaks of the master laser as the length of the cavity is scanned over one free spectral range, the long-term stability of the master laser is transferred to the slave lasers. By using fast analog peak detection and low-latency microcontroller-based digital feedback, with a scanning frequency of 3 kHz, we obtain a feedback bandwidth of 380 Hz and a relative stability of better than 10 kHz at timescales longer than 1 s, a significant improvement on previous scanning-cavity stabilization systems.
Temperature stability of intersubband transitions in AlN/GaN quantum wells
Authors: Berland Kristian , Stattin Martin , Farivar Rashid , Sultan D. M. S. , Hyldgaard Per , Larsson Anders , Wang Shu Min , Andersson Thorvald G.
Published: July 2010

Temperature dependence of intersubband transitions in AlN/GaN multiple quantum wells grown with molecular beam epitaxy is investigated both by absorption studies at different temperatures and modeling of conduction-band electrons. For the absorption study, the sample is heated in increments up to 400 °C. The self-consistent Schrödinger–Poisson modeling includes temperature effects of the band gap and the influence of thermal expansion on the piezoelectric field. We find that the intersubband absorption energy decreases only by ∼6 meV at 400 °C relative to its room temperature value.
Photoemission of Si 1s→2pz transition in GaAs/AlGaAs quantum well for zero-dimensional states infrared detection
Authors: Antoni Thomas , Carras Mathieu , Marcadet Xavier , Vinter Borge , Berger Vincent
Published: July 2010

Intersubband absorption in a GaAs/AlGaAs quantum well usually happens between two two-dimensional (2D) electronic states. However for sufficiently low doping levels, the electrons can be entirely distributed on the silicon localized states. We demonstrate that depending on the temperature, absorption in such structures is dominated either by 2D quantum well states or by zero-dimensional localized Si states. We find a regime where the localized states are the main contributors to the photocurrent, this is expected to strongly impact the behavior of quantum well infrared photodetectors.
Detailed magnetic structure of Zn1−xNixFe2O4 nanoparticles
Authors: Ying Y. , Eom T. W. , Lee Y. P. , Ling L. S. , Mathe V. L.
Published: July 2010

The structural and the magnetic properties of Zn1−xNixFe2O4 (x=0, 0.20, 0.40, 0.60, 0.80, and 1.00) nanoparticles were investigated. The structure and the particle size were measured by x-ray diffraction and scanning electron microscopy. For ZnFe2O4 nanoparticle, particle-size reduction induces the ionic exchange between Zn and Fe ions and promotes the formation of ferrimagnetic (FI) clusters. For NiFe2O4, particle-size reduction causes surface spin disorder in nanoparticles, suppressing the ferrimagnetism. For the Zn-rich Zn1−xNixFe2O4 (x=0.20 and 0.40) nanoparticles, the Ni doping in ZnFe2O4 promotes the ionic redistribution, resulting in the enhancement of FI clusters and a strong ferrimagnetism. For the Ni-rich Zn1−xNixFe2O4 (x=0.60 and 0.80), the Zn doping in NiFe2O4 also induces strong ferrimagnetism since it decreases the magnetic moment of A sublattices and weakens the surface spin disorder in nanoparticles. Spin-glasslike behavior in the series of samples is reported. Especially for NiFe2O4, through measuring the ac susceptibility and employing the critical power and the Vogel–Fulcher models, the dynamics of spin-glasslike state is discussed.
Silver induced faceting of Si(112)
Authors: Nabbefeld T. , Wiethoff C. , Meyer zu Heringdorf F.-J. , Horn-von Hoegen M.
Published: July 2010

Si nanowires grown in ultrahigh vacuum by metal-catalyzed vapor-liquid-solid epitaxy are known to exhibit sidewalls with {112}-type orientation. For some metals the sidewalls show pronounced faceting. Ag induced faceting on Si(112) surfaces was studied in situ by spot-profile-analyzing low energy electron diffraction and ex situ atomic force microscopy. The (112) surface decomposes into (115)- and (111)-(3×3)-facets, both of which are Ag terminated. The width of the facets is kinetically limited and varies between 6 nm at T<550 °C and 30 nm at T=690 °C.
In situ investigation of self-induced GaN nanowire nucleation on Si
Authors: Chèze C. , Geelhaar L. , Trampert A. , Riechert H.
Published: July 2010

The nucleation of GaN nanowires grown by molecular beam epitaxy on bare Si(111) and Si(001) has been investigated in situ by reflection high-energy electron diffraction (RHEED) and line-of-sight quadrupole mass spectrometry. On either substrate, the incorporation rate of Ga increases in two steps to steady-state conditions, and the RHEED transmission pattern of GaN appears only in the second stage. Ex situ transmission electron microscopy on samples from both stages grown on Si(001) revealed that the nanowire nucleation is strongly affected by the simultaneous nitridation of the Si substrate.
Soft-solution route to ZnO nanowall array with low threshold power density
Authors: Jang Eue-Soon , Chen Xiaoyuan , Won Jung-Hee , Chung Jae-Hun , Jang Du-Jeon , Kim Young-Woon , Choy Jin-Ho
Published: July 2010

ZnO nanowall array (ZNWA) has been directionally grown on the buffer layer of ZnO nanoparticles dip-coated on Si-wafer under a soft solution process. Nanowalls on substrate are in most suitable shape and orientation not only as an optical trap but also as an optical waveguide due to their unique growth habit, V[011¯0]⪢V[0001]≈V[0001¯]. Consequently, the stimulated emission at 384 nm through nanowalls is generated by the threshold power density of only 25 kW/cm2. Such UV lasing properties are superior to those of previously reported ZnO nanorod arrays. Moreover, there is no green (defect) emission due to the mild procedure to synthesize ZNWA.
Femtosecond laser fabrication of high reflectivity micromirrors
Authors: Brodoceanu D. , Cole G. D. , Kiesel N. , Aspelmeyer M. , Bäuerle D.
Published: July 2010

High-quality freestanding micromirrors consisting of 40 dielectric layers on silicon have been fabricated by ultrashort-pulse laser ablation in combination with laser-assisted wet chemical etching. Backside material removal enables direct access to both faces of the dielectric coating. The amplitude reflectance of the micromirrors has been determined by Fabry–Pérot interferometry; a finesse in excess of 8900±700, corresponding to a reflectivity exceeding 99.95%, has been found. The mechanical quality factor, Q, of the microresonators, measured at 20 K, is determined to be between 5000 and 6000.
Direct observation of microscopic change induced by oxygen vacancy drift in amorphous TiO2 thin films
Authors: Jeong Hu Young , Lee Jeong Yong , Choi Sung-Yool
Published: July 2010

To clarify the resistive switching and failure mechanisms in Al/amorphous TiO2/Al devices we investigate the microscopic change in amorphous titanium oxide films and interface layers after the set process according to film deposition temperatures. For low temperature (<150 °C) samples, the thickness of top interface layer decreased after the set process due to the dissociation of a top interface layer by uniform migration of oxygen vacancies. Meanwhile, for high temperature samples, crystalline TiO phases emerged in the failed state, meaning the formation of conducting paths from the local clustering of oxygen vacancies in nonhomogeneous titanium oxide film.
Bias-induced offset effect overlapped on bipolar-resistance effect based on Co/SiO2/Si structure
Authors: Yu Chong Qi , Wang Hui
Published: July 2010

Recent study shows the resistance of a metal-oxide-semiconductor (MOS) structure can be controlled by a laser via a bipolar-resistance effect (BRE). Based on this BRE phenomenon, we find an overlapped offset effect which is induced by an external bias applying to the structure. This offset effect features with a moveable equilibrium point of BRE, suggesting a combined control to the resistance and adding functionality to the MOS-based photoelectric devices.
Observation of ultrasonic backward beam displacement in transmission through a solid having superimposed periodicity
Authors: Herbison Sarah W. , Vander Weide John M. , Declercq Nico F.
Published: July 2010

The backward displacement of an ultrasonic beam on a periodically corrugated liquid–solid interface was originally observed in 1976. Additional study of the phenomenon has occurred recently, as further studies of acoustic and elastic wave interaction with periodic surfaces and structures have been driven by increasing interest in phononic crystals. Until now, the phenomenon has only been observed in reflection. This study reports results from experiments that investigate whether a backward beam displacement can also occur in transmission through the interior of a solid. The results indicate that a backward shift may in fact be observed in all fields generated. Therefore, ultrasonic backward beam displacements are not only a reflection phenomenon but may also be observed in transmission.
Resolvin E1-induced intestinal alkaline phosphatase promotes resolution of inflammation through LPS detoxification
Authors: Campbell Eric L. , MacManus Christopher F. , Kominsky Douglas J. , Keely Simon , Glover Louise E. , Bowers Brittelle E. , Scully Melanie , Bruyninckx Walter J. , Colgan Sean P.
Published: July 2010

Resolvin-E1 (RvE1) has been demonstrated to promote inflammatory resolution in numerous disease models. Given the importance of epithelial cells to coordination of mucosal inflammation, we hypothesized that RvE1 elicits an epithelial resolution signature. Initial studies revealed that the RvE1-receptor (ChemR23) is expressed on intestinal epithelial cells (IECs) and that microarray profiling of cells exposed to RvE1 revealed regulation of inflammatory response gene expression. Notably, RvE1 induced intestinal alkaline phosphatase (ALPI) expression and significantly enhanced epithelial ALPI enzyme activity. One role recently attributed to ALPI is the detoxification of bacterial LPS. In our studies, RvE1-exposed epithelia detoxified LPS (assessed by attenuation of NF-κB signaling). Furthermore, in epithelial-bacterial interaction assays, we determined that ALPI retarded the growth of
Escherichia coli
. To define these features in vivo, we used a murine dextran sulfate sodium (DSS) model of colitis. Compared with vehicle controls, administration of RvE1 resulted in significant improvement of disease activity indices (e.g., body weight, colon length) concomitant with increased ALPI expression in the intestinal epithelium. Moreover, inhibition of ALPI activity resulted in increased severity of colitis in DSS-treated animals and partially abrogated the protective influence of RvE1. Together, these data implicate a previously unappreciated role for ALPI in RvE1-mediated inflammatory resolution.
Targeted metagenomics and ecology of globally important uncultured eukaryotic phytoplankton
Authors: Cuvelier Marie L. , Allen Andrew E. , Monier Adam , McCrow John P. , Messié Monique , Tringe Susannah G. , Woyke Tanja , Welsh Rory M. , Ishoey Thomas , Lee Jae-Hyeok , Binder Brian J. , DuPont Chris L. , Latasa Mikel , Guigand Cédric , Buck Kurt R. , Hilton Jason , Thiagarajan Mathangi , Caler Elisabet , Read Betsy , Lasken Roger S. , Chavez Francisco P. , Worden Alexandra Z.
Published: July 2010

Among eukaryotes, four major phytoplankton lineages are responsible for marine photosynthesis; prymnesiophytes, alveolates, stramenopiles, and prasinophytes. Contributions by individual taxa, however, are not well known, and genomes have been analyzed from only the latter two lineages. Tiny “picoplanktonic” members of the prymnesiophyte lineage have long been inferred to be ecologically important but remain poorly characterized. Here, we examine pico-prymnesiophyte evolutionary history and ecology using cultivation-independent methods. 18S rRNA gene analysis showed pico-prymnesiophytes belonged to broadly distributed uncultivated taxa. Therefore, we used targeted metagenomics to analyze uncultured pico-prymnesiophytes sorted by flow cytometry from subtropical North Atlantic waters. The data reveal a composite nuclear-encoded gene repertoire with strong green-lineage affiliations, which contrasts with the evolutionary history indicated by the plastid genome. Measured pico-prymnesiophyte growth rates were rapid in this region, resulting in primary production contributions similar to the cyanobacterium
Prochlorococcus
. On average, pico-prymnesiophytes formed 25% of global picophytoplankton biomass, with differing contributions in five biogeographical provinces spanning tropical to subpolar systems. Elements likely contributing to success include high gene density and genes potentially involved in defense and nutrient uptake. Our findings have implications reaching beyond pico-prymnesiophytes, to the prasinophytes and stramenopiles. For example, prevalence of putative Ni-containing superoxide dismutases (SODs), instead of Fe-containing SODs, seems to be a common adaptation among eukaryotic phytoplankton for reducing Fe quotas in low-Fe modern oceans. Moreover, highly mosaic gene repertoires, although compositionally distinct for each major eukaryotic lineage, now seem to be an underlying facet of successful marine phytoplankton.
Wnt5b–Ryk pathway provides directional signals to regulate gastrulation movement
Authors: Lin Shengda , Baye Lisa M. , Westfall Trudi A. , Slusarski Diane C.
Published: July 2010

Noncanonical Wnts are largely believed to act as permissive cues for vertebrate cell movement via Frizzled (Fz). In addition to Fz, Wnt ligands are known to regulate neurite outgrowth through an alternative receptor related to tyrosine kinase (Ryk). However, Wnt–Ryk signaling during embryogenesis is less well characterized. In this study, we report a role for Wnt5b as an instructive cue to regulate gastrulation movements through Ryk. In zebrafish, Ryk deficiency impairs Wnt5b-induced Ca2+ activity and directional cell movement. Wnt5b–Ryk signaling promotes polarized cell protrusions. Upon Wnt5b stimulation, Fz2 but not Ryk recruits Dishevelled to the cell membrane, suggesting that Fz2 and Ryk mediate separate pathways. Using co-culture assays to generate directional Wnt5b cues, we demonstrate that Ryk-expressing cells migrate away from the Wnt5b source. We conclude that full-length Ryk conveys Wnt5b signals in a directional manner during gastrulation.
The Importance of Leadership in Preventing Healthcare-Associated Infection: Results of a Multisite Qualitative Study
Authors: Saint Sanjay , Kowalski Christine P. , Banaszak-Holl Jane , Forman Jane , Damschroder Laura , Krein Sarah L.
Published: July 2010

Objective.

Healthcare-associated infection (HAI) is costly and causes substantial morbidity. We sought to understand why some hospitals were engaged in HAI prevention activities while others were not. Because preliminary data indicated that hospital leadership played an important role, we sought better to understand which behaviors are exhibited by leaders who are successful at implementing HAI prevention practices in US hospitals.

Methods.

We report phases 2 and 3 of a 3-phase study. In phase 2, 14 purposefully sampled US hospitals were selected from among the 72% of 700 invited hospitals whose lead infection preventionist had completed a quantitative survey on HAI prevention during phase 1. Qualitative data were collected during 38 semistructured phone interviews with key personnel at the 14 hospitals. During phase 3, we conducted 48 interviews during 6 in-person site visits to identify recurrent and unifying themes that characterize behaviors of successful leaders.

Results.

We found that successful leaders (1) cultivated a culture of clinical excellence and effectively communicated it to staff; (2) focused on overcoming barriers and dealt directly with resistant staff or process issues that impeded prevention of HAI; (3) inspired their employees; and (4) thought strategically while acting locally, which involved politicking before crucial committee votes, leveraging personal prestige to move initiatives forward, and forming partnerships across disciplines. Hospital epidemiologists and infection preventionists often played more important leadership roles in their hospital's patient safety activities than did senior executives.

Conclusions.

Leadership plays an important role in infection prevention activities. The behaviors of successful leaders could be adopted by others who seek to prevent HAI.
Rising trends of gastric cancer and peptic ulcer in the 19th century
Authors: Sonnenberg A. , Baron J. H.
Published: July 2010

Aliment Pharmacol Ther 2010; 32: 901–907

Background  The risk of dying from gastric cancer appears to have increased among consecutive generations born during the 19th century.

Aim  To follow the time trends of hospitalization for gastric cancer and test whether they confirm such increase.

Methods  Inpatient records of the last two centuries from four hospitals in Scotland and three US hospitals were analysed. Proportional rates of hospitalization for gastric cancer, gastric ulcer and duodenal ulcer were calculated during consecutive 5‐year periods.

Results  The data from all seven cities revealed strikingly similar patterns. No hospital admissions for gastric cancer or peptic ulcer were recorded prior to 1800. Hospital admissions for gastric cancer increased in an exponential fashion throughout the 19th and the beginning of the 20th century. In a majority of cities, the rise in hospitalization for gastric cancer preceded a similar rise in hospitalization for gastric ulcer. Hospitalization for these two latter diagnoses clearly preceded hospitalization for duodenal ulcer by 20–40 years.

Conclusions  The occurrence of gastric cancer, gastric ulcer and duodenal ulcer markedly increased during the 19th century. Improvements in hygiene may have resulted in the decline of infections by other gastrointestinal organisms that had previously kept concomitant infection by Helicobacter pylori suppressed.
Meta‐analysis: interferon improves outcomes following ablation or resection of hepatocellular carcinoma
Authors: Singal A. K. , Freeman Jr D. H. , Anand B. S.
Published: July 2010

Aliment Pharmacol Ther 2010; 32: 851–858

Background  Hepatocellular carcinoma (HCC) is third most common cause of tumour‐related death in the US with hepatitis C virus (HCV) the most common aetiology. Surgical resection and tumour ablation are curative in patients who cannot be transplanted. With native liver having cirrhosis, HCC recurrence is a potential problem.

Aim  To perform a systematic review and meta‐analysis of studies evaluating efficacy of IFN to prevent HCC recurrence after its curative treatment in HCV‐related cirrhosis.

Methods  Ten studies (n = 645, 301 treated with IFN) on the use of IFN after resection or ablation of HCV‐associated HCC were analysed.

Results  Pooled data showed benefit of IFN for HCC prevention with OR (95% CI) of 0.26 (0.15–0.45); P < 0.00001. The proportion of patients surviving at 5 years (n = 505 in 6 studies) was in favour of IFN with OR of 0.31 [(95% CI 0.21–0.46); P < 0.00001]. Data were homogeneous for HCC recurrence (χ2 12.05, P = 0.21) and survival (χ2 6.93, P = 0.44). The benefit of IFN was stronger with sustained virological response compared with nonresponders for HCC recurrence [0.19 (0.06–0.60); P = 0.005] and survival [0.31 (0.11–0.90); P = 0.03].

Conclusion  Interferon treatment after curative resection or ablation of HCC in HCV‐related cirrhotics prevents HCC recurrence and improves survival.
Minimum local analgesic concentration of ropivacaine for intra‐operative caudal analgesia in pre‐school and school age children
Authors: Deng X. M. , Xiao W. J. , Tang G. Z. , Luo M. P. , Xu K. L.
Published: July 2010

We compared the minimum local analgesia concentration of ropivacaine for intra‐operative caudal analgesia in pre‐school and school age children. Fifty‐one boys, undergoing hypospadius repair surgery, were stratified into pre‐school or school age groups. After induction of anaesthesia, caudal block was performed with ropivacaine 1 ml.kg−1 of the desired concentration. The first child in each group received ropivacaine 0.125%, and subsequent concentrations were determined by the analgesic response of the previous patient using Dixon’s up‐and‐down method. Under general anaesthesia with 0.7 minimum alveolar concentration of sevoflurane, the minimum local analgesia concentration of ropivacaine for intra‐operative caudal block was 34% greater in school age than in pre‐school age boys (0.143% (95% CI 0.132–0.157%) vs 0.107% (95% CI 0.089–0.122%), respectively; p < 0.001). This study indicates that a higher concentration of ropivacaine is needed for school age than pre‐school age children to provide intra‐operative caudal analgesia when combined with general anaesthesia.