bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of strain on the electron effective mass in GaN and AlN
Authors: Dreyer C. E. , Janotti A. , Van de Walle C. G.
Published: April 2013

Stress is known to strongly alter the effective mass in semiconductors, changing the mobility of carriers. Transport measurements on AlGaN/GaN heterostructures indicated a large increase in mobility under tensile strain [M. Azize and T. Palacios, J. Appl. Phys. 108, 023707 (2010)]. Using first-principles methods, we calculate the variation of electron effective mass in GaN and AlN under hydrostatic and biaxial stress. Unexpected trends are found, which are explained within k·p theory through a variation of the interband momentum matrix elements. The magnitude of the effective-mass reduction is too small to explain the experimentally reported increase in mobility.
Low frequency resistance and critical current fluctuations in Al-based Josephson junctions
Authors: Nugroho C. D. , Orlyanchik V. , Van Harlingen D. J.
Published: April 2013

We present low-temperature measurements of the low-frequency 1/f noise arising from an ensemble of two-level fluctuators in the oxide barrier of Al/AlOx/Al Josephson junctions. The fractional noise power spectrum of the critical-current and normal-state resistance has similar magnitudes and scale linearly with temperature, implying an equivalence between the two. Compiling our results and published data, we deduce the area and temperature scaling of the noise for AlOx barrier junctions. We find that the density of two-level fluctuators in the junction barrier is similar to the typical value in glassy systems. We discuss the implications and consistency with recent qubit experiments.
Block-and-break generation of microdroplets with fixed volume
Authors: van Steijn Volkert , Korczyk Piotr M. , Derzsi Ladislav , Abate Adam R. , Weitz David A. , Garstecki Piotr
Published: April 2013

We introduce a novel type of droplet generator that produces droplets of a volume set by the geometry of the droplet generator and not by the flow rates of the liquids. The generator consists of a classic T-junction with a bypass channel. This bypass directs the continuous fluid around the forming droplets, so that they can fill the space between the inlet of the dispersed phase and the exit of the bypass without breaking. Once filled, the dispersed phase blocks the exit of the bypass and is squeezed by the continuous fluid and broken off from the junction. We demonstrate the fixed-volume droplet generator for (i) the formation of monodisperse droplets from a source of varying flow rates, (ii) the formation of monodisperse droplets containing a gradation of solute concentration, and (iii) the parallel production of monodisperse droplets.
Exotic reinforcement of thermoelectric power driven by Ca doping in layered Bi2Sr2−xCaxCo2Oy
Authors: Yin L. H. , Ang R. , Huang Z. H. , Liu Y. , Tan S. G. , Huang Y. N. , Zhao B. C. , Song W. H. , Sun Y. P.
Published: April 2013

We have systematically investigated thermoelectric properties of layered Bi2Sr2−xCaxCo2Oy (0.0≤x≤2.0) by a series of Ca doping. The resistivity presents a metal-insulator transition for lightly doped samples, while such behavior is not observed for heavily doped samples. Amazingly, the Ca doping induces an exotic reinforcement of thermoelectric power S in the whole x range. In particular, the Sommerfeld coefficient is dependent on carrier density and also as a function of density of states at the Fermi level which is responsible to the persistent enhancement of large S. Moreover, thermoelectric performance can be effectively modulated by temperature control.
Improved ionic conductivity in strained yttria-stabilized zirconia thin films
Authors: Jiang Jun , Hu Xiaocao , Shen Weida , Ni Chaoying , Hertz Joshua L.
Published: April 2013

Yttria-stabilized zirconia (YSZ) thin films with thickness ranging from 6 nm to 100 nm were prepared by RF sputtering on (0001) Al2O3 substrates and exhibited epitaxial growth along (111)[110] YSZ//(0001)[101¯0] Al2O3. While the thicker films exhibited oxygen ion conductivities similar to bulk samples, the thinnest films exhibited increased ionic conductivity and a reduced activation energy of 0.79 eV between 300 °C–650 °C. Concomitant with the improved conductivity of the thinner films is an increase in the out-of-plane lattice parameter, matching theoretical expectations regarding tensile strain, and the introduction of edge dislocations, which may additionally assist in-plane ionic conduction.
Controlling the Rayleigh instability of nanowires
Authors: Gill S. P. A.
Published: April 2013

Nanowires can be subject to morphological instability at high temperatures, causing them to break into nanochains. The size and separation of the resulting nanoparticles are determined by the wavelength of this instability. It is of interest to control this process, either to increase thermal stability or to use it as a processing route. An analytical model is developed to determine the effect of two controllable parameters on this wavelength, namely temperature and substrate topography, via evaporation and surface grooving. It is found that the wavelength increases with groove angle and evaporation rate and that grooves increase thermal stability.
Ultraviolet Raman spectroscopy of GaN/AlN core-shell nanowires: Core, shell, and interface modes
Authors: Cros A. , Mata R. , Hestroffer K. , Daudin B.
Published: April 2013

The vibrational properties of GaN/AlN core-shell nanowire heterostructures with shell thicknesses ranging from 0.5 to 12 nm have been investigated by means of Raman spectroscopy with ultraviolet and visible excitation. The selection of an excitation line close to the GaN band gap allows the study of the strain state of the GaN core, while excitation at higher energies activates modes localized at the core-shell interface and the AlN shell, which are as well strain dependent. The results are compared with calculations of the vibrational modes based on the dielectric continuum model, including strain through the continuum elasticity theory.
Production, preservation, and biological processing of mass-independent sulfur isotope fractionation in the Archean surface environment
Authors: Halevy Itay
Published: April 2013

Mass-independent fractionation of sulfur isotopes (S MIF) in Archean and Paleoproterozoic rocks provides strong evidence for an anoxic atmosphere before ∼2,400 Ma. However, the origin of this isotopic anomaly remains unclear, as does the identity of the molecules that carried it from the atmosphere to Earth’s surface. Irrespective of the origin of S MIF, processes in the biogeochemical sulfur cycle modify the primary signal and strongly influence the S MIF preserved and observed in the geological record. Here, a detailed model of the marine sulfur cycle is used to propagate and distribute atmospherically derived S MIF from its delivery to the ocean to its preservation in the sediment. Bulk pyrite in most sediments carries weak S MIF because of microbial reduction of most sulfur compounds to form isotopically homogeneous sulfide. Locally, differential incorporation of sulfur compounds into pyrite leads to preservation of S MIF, which is predicted to be most highly variable in nonmarine and shallow-water settings. The Archean ocean is efficient in diluting primary atmospheric S MIF in the marine pools of sulfate and elemental sulfur with inputs from SO
2
and H
2
S, respectively. Preservation of S MIF with the observed range of magnitudes requires the S MIF production mechanism to be moderately fractionating (

20–40‰). Constraints from the marine sulfur cycle allow that either elemental sulfur or organosulfur compounds (or both) carried S MIF to the surface, with opposite sign to S MIF in SO
2
and H
2
SO
4
. Optimal progress requires observations from nonmarine and shallow-water environments and experimental constraints on the reaction of photoexcited SO
2
with atmospheric hydrocarbons.
Characterization of the free-energy landscapes of proteins by NMR-guided metadynamics
Authors: Granata Daniele , Camilloni Carlo , Vendruscolo Michele , Laio Alessandro
Published: April 2013

The use of free-energy landscapes rationalizes a wide range of aspects of protein behavior by providing a clear illustration of the different states accessible to these molecules, as well as of their populations and pathways of interconversion. The determination of the free-energy landscapes of proteins by computational methods is, however, very challenging as it requires an extensive sampling of their conformational spaces. We describe here a technique to achieve this goal with relatively limited computational resources by incorporating nuclear magnetic resonance (NMR) chemical shifts as collective variables in metadynamics simulations. As in this approach the chemical shifts are not used as structural restraints, the resulting free-energy landscapes correspond to the force fields used in the simulations. We illustrate this approach in the case of the third Ig-binding domain of protein G from streptococcal bacteria (GB3). Our calculations reveal the existence of a folding intermediate of GB3 with nonnative structural elements. Furthermore, the availability of the free-energy landscape enables the folding mechanism of GB3 to be elucidated by analyzing the conformational ensembles corresponding to the native, intermediate, and unfolded states, as well as the transition states between them. Taken together, these results show that, by incorporating experimental data as collective variables in metadynamics simulations, it is possible to enhance the sampling efficiency by two or more orders of magnitude with respect to standard molecular dynamics simulations, and thus to estimate free-energy differences among the different states of a protein with a k

B

T accuracy by generating trajectories of just a few microseconds.
Oriented assembly of polyhedral plasmonic nanoparticle clusters
Authors: Henzie Joel , Andrews Sean C. , Ling Xing Yi , Li Zhiyong , Yang Peidong
Published: April 2013

Shaped colloids can be used as nanoscale building blocks for the construction of composite, functional materials that are completely assembled from the bottom up. Assemblies of noble metal nanostructures have unique optical properties that depend on key structural features requiring precise control of both position and connectivity spanning nanometer to micrometer length scales. Identifying and optimizing structures that strongly couple to light is important for understanding the behavior of surface plasmons in small nanoparticle clusters, and can result in highly sensitive chemical and biochemical sensors using surface-enhanced Raman spectroscopy (SERS). We use experiment and simulation to examine the local surface plasmon resonances of different arrangements of Ag polyhedral clusters. High-resolution transmission electron microscopy shows that monodisperse, atomically smooth Ag polyhedra can self-assemble into uniform interparticle gaps that result in reproducible SERS enhancement factors from assembly to assembly. We introduce a large-scale, gravity-driven assembly method that can generate arbitrary nanoparticle clusters based on the size and shape of a patterned template. These templates enable the systematic examination of different cluster arrangements and provide a means of constructing scalable and reliable SERS sensors.
Biomimetic model to reconstitute angiogenic sprouting morphogenesis in vitro
Authors: Nguyen Duc-Huy T. , Stapleton Sarah C. , Yang Michael T. , Cha Susie S. , Choi Colin K. , Galie Peter A. , Chen Christopher S.
Published: April 2013

Angiogenesis is a complex morphogenetic process whereby endothelial cells from existing vessels invade as multicellular sprouts to form new vessels. Here, we have engineered a unique organotypic model of angiogenic sprouting and neovessel formation that originates from preformed artificial vessels fully encapsulated within a 3D extracellular matrix. Using this model, we screened the effects of angiogenic factors and identified two distinct cocktails that promoted robust multicellular endothelial sprouting. The angiogenic sprouts in our system exhibited hallmark structural features of in vivo angiogenesis, including directed invasion of leading cells that developed filopodia-like protrusions characteristic of tip cells, following stalk cells exhibiting apical–basal polarity, and lumens and branches connecting back to the parent vessels. Ultimately, sprouts bridged between preformed channels and formed perfusable neovessels. Using this model, we investigated the effects of angiogenic inhibitors on sprouting morphogenesis. Interestingly, the ability of VEGF receptor 2 inhibition to antagonize filopodia formation in tip cells was context-dependent, suggesting a mechanism by which vessels might be able to toggle between VEGF-dependent and VEGF-independent modes of angiogenesis. Like VEGF, sphingosine-1-phosphate also seemed to exert its proangiogenic effects by stimulating directional filopodial extension, whereas matrix metalloproteinase inhibitors prevented sprout extension but had no impact on filopodial formation. Together, these results demonstrate an in vitro 3D biomimetic model that reconstitutes the morphogenetic steps of angiogenic sprouting and highlight the potential utility of the model to elucidate the molecular mechanisms that coordinate the complex series of events involved in neovascularization.
Regulation of Torsin ATPases by LAP1 and LULL1
Authors: Zhao Chenguang , Brown Rebecca S. H. , Chase Anna R. , Eisele Markus R. , Schlieker Christian
Published: April 2013

Significance

Torsins belong to the AAA+ (ATPases associated with a variety of cellular activities) ATPase superfamily, the members of which disassemble protein complexes or unfold proteins. Here, we provide evidence that the activity of Torsins is tightly regulated by two proteins that reside in the endoplasmic reticulum and the perinuclear space. This regulatory mechanism provides the framework for a better understanding of phenotypes in animal models, and allows us to define the molecular defect underlying TorsinA dystonia.
Stage-specific regulation of natural killer cell homeostasis and response against viral infection by microRNA-155
Authors: Zawislak Carolyn L. , Beaulieu Aimee M. , Loeb Gabriel B. , Karo Jenny , Canner David , Bezman Natalie A. , Lanier Lewis L. , Rudensky Alexander Y. , Sun Joseph C.
Published: April 2013

Natural killer (NK) cells function in the recognition and destruction of host cells infected with pathogens. Many regulatory mechanisms govern the potent responses of NK cells, both at the cellular and molecular level. Ablation of microRNA (miRNA) processing enzymes demonstrated that miRNAs play critical roles in NK cell differentiation and function; however, the role of individual miRNAs requires further investigation. Using mice containing a targeted deletion of microRNA-155 (miR-155), we observed defects in NK cell maintenance and maturation at steady state, as well as in homeostatic proliferation in lymphopenic mice. In addition, we discovered that miR-155 is up-regulated in activated NK cells during mouse cytomegalovirus (MCMV) infection in response to signals from the proinflammatory cytokines IL-12 and IL-18 and through signal transducer and activator of transcription 4 (STAT4) signaling. Although miR-155 was found to be dispensable for cytotoxicity and cytokine production when triggered through activating receptors, NK cells lacking miR-155 exhibited severely impaired effector and memory cell numbers in both lymphoid and nonlymphoid tissues after MCMV infection. We demonstrate that miR-155 differentially targets Noxa and suppressor of cytokine signaling 1 (SOCS1) in NK cells at distinct stages of homeostasis and activation. NK cells constitutively expressing Noxa and SOCS1 exhibit profound defects in expansion during the response to MCMV infection, suggesting that their regulation by miR-155 promotes antiviral immunity.
HPV-18
E6
mutants reveal p53 modulation of viral DNA amplification in organotypic cultures
Authors: Kho Eun-Young , Wang Hsu-Kun , Banerjee N. Sanjib , Broker Thomas R. , Chow Louise T.
Published: April 2013

Human papillomaviruses (HPVs) amplify in differentiated strata of a squamous epithelium. The HPV E7 protein destabilizes the p130/retinoblastoma susceptibility protein family of tumor suppressors and reactivates S-phase reentry, thereby facilitating viral DNA amplification. The high-risk HPV E6 protein destabilizes the p53 tumor suppressor and many other host proteins. However, the critical E6 targets relevant to viral DNA amplification have not been identified, because functionally significant
E6
mutants are not stably maintained in transfected cells. Using Cre-loxP recombination, which efficiently generates HPV genomic plasmids in transfected primary human keratinocytes, we have recapitulated a highly productive infection of HPV-18 in organotypic epithelial cultures. By using this system, we now report the characterization of four HPV-18
E6
mutations. An E6 null mutant accumulated high levels of p53 and amplified very poorly. p53 siRNA or ectopic WT E6 partially restored amplification, whereas three missense
E6
mutations that did not effectively destabilize p53 complemented the null mutant poorly. Unexpectedly,
in cis
, two of the missense mutants amplified, albeit to a lower extent than the WT and only in cells with undetectable p53. These observations and others implicate p53 and additional host proteins in regulating viral DNA amplification and also suggest an inhibitory effect of E6 overexpression. We show that high levels of viral DNA amplification are critical for late protein expression and report several previously undescribed viral RNAs, including bicistronic transcripts predicted to encode E5 and L2 or an alternative form of E1^E4 and L1.
MHC II tetramers visualize human CD4+ T cell responses to Epstein–Barr virus infection and demonstrate atypical kinetics of the nuclear antigen EBNA1 response
Authors: Long Heather M. , Chagoury Odette L. , Leese Alison M. , Ryan Gordon B. , James Eddie , Morton Laura T. , Abbott Rachel J.M. , Sabbah Shereen , Kwok William , Rickinson Alan B.
Published: April 2013

Virus-specific CD4+ T cells are key orchestrators of host responses to viral infection yet, compared with their CD8+ T cell counterparts, remain poorly characterized at the single cell level. Here we use nine MHC II–epitope peptide tetramers to visualize human CD4+ T cell responses to Epstein–Barr virus (EBV), the causative agent of infectious mononucleosis (IM), a disease associated with large virus-specific CD8+ T cell responses. We find that, while not approaching virus-specific CD8+ T cell expansions in magnitude, activated CD4+ T cells specific for epitopes in the latent antigen EBNA2 and four lytic cycle antigens are detected at high frequencies in acute IM blood. They then fall rapidly to values typical of life-long virus carriage where most tetramer-positive cells display conventional memory markers but some, unexpectedly, revert to a naive-like phenotype. In contrast CD4+ T cell responses to EBNA1 epitopes are greatly delayed in IM patients, in line with the well-known but hitherto unexplained delay in EBNA1 IgG antibody responses. We present evidence from an in vitro system that may explain these unusual kinetics. Unlike other EBNAs and lytic cycle proteins, EBNA1 is not naturally released from EBV-infected cells as a source of antigen for CD4+ T cell priming.
An Environmental Disinfection Odyssey: Evaluation of Sequential Interventions to Improve Disinfection of Clostridium difficile Isolation Rooms
Authors: Sitzlar Brett , Deshpande Abhishek , Fertelli Dennis , Kundrapu Sirisha , Sethi Ajay K. , Donskey Curtis J.
Published: April 2013

Objective.

Effective disinfection of hospital rooms after discharge of patients with Clostridium difficile infection (CDI) is necessary to prevent transmission. We evaluated the impact of sequential cleaning and disinfection interventions by culturing high-touch surfaces in CDI rooms after cleaning.

Design.

Prospective intervention.

Setting.

A Veterans Affairs hospital.

Interventions.

During a 21-month period, 3 sequential tiered interventions were implemented: (1) fluorescent markers to provide monitoring and feedback on thoroughness of cleaning facility-wide, (2) addition of an automated ultraviolet radiation device for adjunctive disinfection of CDI rooms, and (3) enhanced standard disinfection of CDI rooms, including a dedicated daily disinfection team and implementation of a process requiring supervisory assessment and clearance of terminally cleaned CDI rooms. To determine the impact of the interventions, cultures were obtained from CDI rooms after cleaning and disinfection.

Results.

The fluorescent marker intervention improved the thoroughness of cleaning of high-touch surfaces (from 47% to 81% marker removal; P < .0001). Relative to the baseline period, the prevalence of positive cultures from CDI rooms was reduced by 14% (P = .024), 48% (P>.001), and 89% (P = .006) with interventions 1, 2, and 3, respectively. During the baseline period, 67% of CDI rooms had positive cultures after disinfection, whereas during interventions periods 1, 2, and 3 the percentages of CDI rooms with positive cultures after disinfection were reduced to 57%, 35%, and 7%, respectively.

Conclusions.

An intervention that included formation of a dedicated daily disinfection team and implementation of a standardized process for clearing CDI rooms achieved consistent CDI room disinfection. Culturing of CDI rooms provides a valuable tool to drive improvements in environmental disinfection.
Analysis of Latino populations from GALA and MEC studies reveals genomic loci with biased local ancestry estimation
Authors: Pasaniuc Bogdan , Sankararaman Sriram , Torgerson Dara G. , Gignoux Christopher , Zaitlen Noah , Eng Celeste , Rodriguez-Cintron William , Chapela Rocio , Ford Jean G. , Avila Pedro C. , Rodriguez-Santana Jose , Chen Gary K. , Le Marchand Loic , Henderson Brian , Reich David , Haiman Christopher A. , Gonzàlez Burchard Esteban , Halperin Eran
Published: April 2013

Motivation: Local ancestry analysis of genotype data from recently admixed populations (e.g. Latinos, African Americans) provides key insights into population history and disease genetics. Although methods for local ancestry inference have been extensively validated in simulations (under many unrealistic assumptions), no empirical study of local ancestry accuracy in Latinos exists to date. Hence, interpreting findings that rely on local ancestry in Latinos is challenging.

Results: Here, we use 489 nuclear families from the mainland USA, Puerto Rico and Mexico in conjunction with 3204 unrelated Latinos from the Multiethnic Cohort study to provide the first empirical characterization of local ancestry inference accuracy in Latinos. Our approach for identifying errors does not rely on simulations but on the observation that local ancestry in families follows Mendelian inheritance. We measure the rate of local ancestry assignments that lead to Mendelian inconsistencies in local ancestry in trios (MILANC), which provides a lower bound on errors in the local ancestry estimates. We show that MILANC rates observed in simulations underestimate the rate observed in real data, and that MILANC varies substantially across the genome. Second, across a wide range of methods, we observe that loci with large deviations in local ancestry also show enrichment in MILANC rates. Therefore, local ancestry estimates at such loci should be interpreted with caution. Finally, we reconstruct ancestral haplotype panels to be used as reference panels in local ancestry inference and show that ancestry inference is significantly improved by incoroprating these reference panels.

Availability and implementation: We provide the reconstructed reference panels together with the maps of MILANC rates as a public resource for researchers analyzing local ancestry in Latinos at http://bogdanlab.pathology.ucla.edu.

Contact:  bpasaniuc@mednet.ucla.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
Video-Assisted Thoracic Surgery Lobectomy versus Lobectomy by Thoracotomy for Lung Cancer: Pilot Study
Authors: Papiashvilli Michael , Sasson Lior , Azzam Sharbel , Hayat Henri , Schreiber Letizia , Ezri Tiberiu , Priel Israel E.
Published: April 2013

Objective

Video-assisted thoracic surgery lobectomy (VATS-L) has become accepted as a safe and effective procedure to treat early-stage non–small cell lung carcinoma (NSCLC). However, the advantages of VATS-L compared with lobectomy by thoracotomy (TL) remain controversial. The aim of this study was to compare the outcomes of patients who underwent VATS-L with those who underwent TL.

Methods

We studied 103 patients who underwent surgery for operable NSCLC between October 2009 and March 2012. All operations were performed by a single surgeon. The inclusion and exclusion criteria for VATS-L and TL were formulated before the study was initiated. Data on age, sex, preoperative comorbidities, intraoperative and postoperative complications, hospital stay, morbidity, mortality, and other characteristics were recorded preoperatively, in real time intra-operatively, and during hospitalization and were statistically compared. Comorbidities were scaled according to the Charlson Comorbidity Index, and propensity scores between the patients who underwent TL and VATS-L were compared.

Results

Sixty-three VATS-L operations and 40 TL operations were performed. There were no postoperative complications in 39 patients (61.9%) who underwent VATS-L compared with 25 patients (62.5%) who underwent TL. The patients who underwent TL were significantly younger than the patients who underwent VATS-L (mean ± SD, 64.7 ± 12.6 vs 70.9 ± 8.4; P = 0.003). Hospital stay was not found to be related to the type of surgery (mean ± SD, 8.43 ± 3.15 days vs 8.32 ± 4.13 days; P = 0.888). There were no significant differences when comparing postoperative complications.

Conclusions

Our initial data suggest that VATS-L is a safe procedure in patients with resectable IA/IB NSCLC and may be the preferred strategy for treatment of the older patient population.
Gastrostomy in Children With Cystic Fibrosis and Portal Hypertension
Authors: Vandeleur Moya , Massie John , Oliver Mark
Published: April 2013

Children with cystic fibrosis–associated liver disease (CFALD) and portal hypertension may require supplemental feeding with gastrostomy; however, this could lead to the development of stomal varices. We assessed this risk and nutritional and pulmonary outcome in a series of 7 children with CFALD and portal hypertension. In 35.1 patient‐years of follow‐up, none developed stomal varices or had a gastrointestinal bleed attributable to a varix. There was significant improvement in nutrition and lung function 2 years postinsertion. We conclude that gastrostomy placement for poor nutrition in children with CFALD and portal hypertension is safe and contributes to improved nutritional and pulmonary outcome.
Magnet Ingestions in Children Presenting to US Emergency Departments, 2002–2011
Authors: Abbas Mazen I. , Oliva‐Hemker Maria , Choi Joon , Lustik Michael , Gilger Mark A. , Noel R. Adam , Schwarz Kathleen , Nylund Cade M.
Published: April 2013

Background and Objective:

In the last 10 years, there have been an increasing number of case reports concerning gastrointestinal injury related to magnet ingestions; however, the magnitude of the problem remains to be clearly defined. The aim of the study was to examine the epidemiology of magnet ingestion‐related emergency department (ED) visits among children in the United States.

Methods:

We performed a trend analysis using a nationally representative sample from the US Consumer Product Safety Commission, National Electronic Injury Surveillance System (NEISS) database for ED visits involving magnet ingestion in children younger than 18 years from 2002 to 2011.

Results:

A national estimate of 16,386 (95% CI 12,175–20,598) children younger than 18 years presented to EDs in the United States during the 10‐year study period with possible magnet ingestion. The incidence of visits increased 8.5‐fold (from 0.45/100,000 to 3.75/100,000) from 2002 to 2011 with a 75% average annual increase per year. The majority of patients reported to have ingested magnets were younger than 5 years (54.7%). From 2009 to 2011 there was an increase in older children ingesting multiple small and/or round magnets, with a mean average age of 7.1 ± 0.56 years during the study period.

Conclusions:

There has been an alarming increase in ED visits for magnet ingestion in children. Increased public education and prevention efforts are needed.
Syndromic surveillance using veterinary laboratory data: data pre-processing and algorithm performance evaluation
Authors: Dórea Fernanda C. , McEwen Beverly J. , McNab W. Bruce , Revie Crawford W. , Sanchez Javier
Published: April 2013

Diagnostic test orders to an animal laboratory were explored as a data source for monitoring trends in the incidence of clinical syndromes in cattle. Four years of real data and over 200 simulated outbreak signals were used to compare pre-processing methods that could remove temporal effects in the data, as well as temporal aberration detection algorithms that provided high sensitivity and specificity. Weekly differencing demonstrated solid performance in removing day-of-week effects, even in series with low daily counts. For aberration detection, the results indicated that no single algorithm showed performance superior to all others across the range of outbreak scenarios simulated. Exponentially weighted moving average charts and Holt–Winters exponential smoothing demonstrated complementary performance, with the latter offering an automated method to adjust to changes in the time series that will likely occur in the future. Shewhart charts provided lower sensitivity but earlier detection in some scenarios. Cumulative sum charts did not appear to add value to the system; however, the poor performance of this algorithm was attributed to characteristics of the data monitored. These findings indicate that automated monitoring aimed at early detection of temporal aberrations will likely be most effective when a range of algorithms are implemented in parallel.
Entrapment of bed bugs by leaf trichomes inspires microfabrication of biomimetic surfaces
Authors: Szyndler Megan W. , Haynes Kenneth F. , Potter Michael F. , Corn Robert M. , Loudon Catherine
Published: April 2013

Resurgence in bed bug infestations and widespread pesticide resistance have greatly renewed interest in the development of more sustainable, environmentally friendly methods to manage bed bugs. Historically, in Eastern Europe, bed bugs were entrapped by leaves from bean plants, which were then destroyed; this purely physical entrapment was related to microscopic hooked hairs (trichomes) on the leaf surfaces. Using scanning electron microscopy and videography, we documented the capture mechanism: the physical impaling of bed bug feet (tarsi) by these trichomes. This is distinct from a Velcro-like mechanism of non-piercing entanglement, which only momentarily holds the bug without sustained capture. Struggling, trapped bed bugs are impaled by trichomes on several legs and are unable to free themselves. Only specific, mechanically vulnerable locations on the bug tarsi are pierced by the trichomes, which are located at effective heights and orientations for bed bug entrapment despite a lack of any evolutionary association. Using bean leaves as templates, we microfabricated surfaces indistinguishable in geometry from the real leaves, including the trichomes, using polymers with material properties similar to plant cell walls. These synthetic surfaces snag the bed bugs temporarily but do not hinder their locomotion as effectively as real leaves.
Modelling of elastic properties of sintered porous materials
Authors: Manoylov A. V. , Borodich F. M. , Evans H. P.
Published: April 2013

Models for prediction of the elastic characteristics of natural and synthetic porous materials are re-examined and new models are introduced. First, the Vavakin–Salganik (VS) model for materials with isolated spherical pores is extended in order to take into account various statistical distributions of pore sizes. It is shown that the predictions of the extended VS model are in good agreement with experimental data for porous materials with isolated pores such as foamed titanium, porous glass and sandstone. However, the model is in a considerable disagreement with the experimental data for materials sintered from metal powders. The disagreement is explained by the presence of merged and open pores whose shapes cannot be well approximated as spheres. Using the theory of geometrical probabilities, the amount of pores that are close enough to overlap is estimated, and a model is introduced where merging pores are modelled as corresponding ellipsoids. Another modification is proposed to take into account open pores. This modification is based on the classical Rabotnov–Kachanov approach to damage accumulation in the loaded material. Finally, predictions given by the above models, and their combination is compared with experiments. A good agreement is observed between the combined model and the available experimental data for a variety of sintered materials.
Anomalous localized resonance using a folded geometry in three dimensions
Authors: Ammari Habib , Ciraolo Giulio , Kang Hyeonbae , Lee Hyundae , Milton Graeme W.
Published: April 2013

If a body of dielectric material is coated by a plasmonic structure of negative dielectric material with non-zero loss parameter, then cloaking by anomalous localized resonance (CALR) may occur as the loss parameter tends to zero. If the coated structure is circular (two dimensions) and the dielectric constant of the shell is a negative constant (with loss parameter), then CALR occurs, and if the coated structure is spherical (three dimensions), then CALR does not occur. The aim of this paper is to show that CALR takes place if the spherical coated structure has a specially designed anisotropic dielectric tensor. The anisotropic dielectric tensor is designed by unfolding a folded geometry.
Protected areas act as establishment centres for species colonizing the UK
Authors: Hiley Jonathan R. , Bradbury Richard B. , Holling Mark , Thomas Chris D.
Published: April 2013

Protected area (PA) networks will remain valuable for conservation, as the global environment changes, if they facilitate the colonization of new regions by species that are shifting their geographical ranges. We tested the extent to which wetland bird species colonizing the UK since 1960 have exploited PAs. Colonization commenced in a PA for all six species that established permanent (greater than 10 years) breeding populations in the UK during this period. Subsequently, birds started to breed outside as well as inside PAs: the colonizing species showing declining fractions of breeding within PAs over time, a trend not seen in already-resident species. PAs were valuable as ‘landing pads’ for range-shifting species first arriving in a new region, and then as ‘establishment centres’ from which viable populations spread. Given future projections of range change across a broad range of taxonomic groups, this role for PAs can be expected to become increasingly important.
FacilitatingWolbachiaintroductions into mosquito populations through insecticide-resistance selection
Authors: Hoffmann Ary A. , Turelli Michael
Published: April 2013

Wolbachiainfections are being introduced into mosquito vectors of human diseases following the discovery that they can block transmission of disease agents. This requires mosquitoes infected with the disease-blockingWolbachiato successfully invade populations lacking the infection. While this process is facilitated by features ofWolbachia, particularly their ability to cause cytoplasmic incompatibility, blockingWolbachiamay produce deleterious effects, such as reduced host viability or fecundity, that inhibit successful local introductions and subsequent spatial spread. Here, we outline an approach to facilitate the introduction and spread ofWolbachiainfections by couplingWolbachiaintroduction to resistance to specific classes of insecticides. The approach takes advantage of very high maternal transmission fidelity ofWolbachiainfections in mosquitoes, complete incompatibility between infected males and uninfected females, the widespread occurrence of insecticide resistance, and the widespread use of chemical control in disease-endemic countries. This approach is easily integrated into many existing control strategies, provides population suppression during release and might be used to introduceWolbachiainfections even with high and seasonally dependent deleterious effects, such as thewMelPop infection introduced intoAedes aegyptifor dengue control. However, possible benefits will need to be weighed against concerns associated with the introduction of resistance alleles.
The importance of the eyes: communication skills in infants of blind parents
Authors: Senju Atsushi , Tucker Leslie , Pasco Greg , Hudry Kristelle , Elsabbagh Mayada , Charman Tony , Johnson Mark H.
Published: April 2013

The effects of selectively different experience of eye contact and gaze behaviour on the early development of five sighted infants of blind parents were investigated. Infants were assessed longitudinally at 6–10, 12–15 and 24–47 months. Face scanning and gaze following were assessed using eye tracking. In addition, established measures of autistic-like behaviours and standardized tests of cognitive, motor and linguistic development, as well as observations of naturalistic parent–child interaction were collected. These data were compared with those obtained from a larger group of sighted infants of sighted parents. Infants with blind parents did not show an overall decrease in eye contact or gaze following when they observed sighted adults on video or in live interactions, nor did they show any autistic-like behaviours. However, they directed their own eye gaze somewhat less frequently towards their blind mothers and also showed improved performance in visual memory and attention at younger ages. Being reared with significantly reduced experience of eye contact and gaze behaviour does not preclude sighted infants from developing typical gaze processing and other social-communication skills. Indeed, the need to switch between different types of communication strategy may actually enhance other skills during development.
Behavioural profiles are shaped by social experience: when, how and why
Authors: Sachser Norbert , Kaiser Sylvia , Hennessy Michael B.
Published: April 2013

The comprehensive understanding of individual variation in behavioural profiles is a current and timely topic not only in behavioural ecology, but also in biopsychological and biomedical research. This study focuses on the shaping of behavioural profiles by the social environment in mammals. We review evidence that the shaping of behavioural profiles occurs from the prenatal phase through adolescence and beyond. We focus specifically on adolescence, a sensitive phase during which environmental stimuli have distinctive effects on the modulation of behavioural profiles. We discuss causation, in particular, how behavioural profiles are shaped by social stimuli through behavioural and neuroendocrine processes. We postulate a central role for maternal hormones during the prenatal phase, for maternal behaviour during lactation and for the interaction of testosterone and stress hormones during adolescence. We refer to evolutionary history and attempt to place developmental shaping into broader evolutionary historical trends. Finally, we address survival value. We argue that the shaping of behavioural profiles by environmental stimuli from the prenatal phase through adolescence represents an effective mechanism for repeated and rapid adaptation during the lifetime. Notably, the adolescent phase may provide a last chance for correction if the future environment deviates from that predicted in earlier phases.
Maps of open chromatin highlight cell type–restricted patterns of regulatory sequence variation at hematological trait loci
Authors: Paul Dirk S. , Albers Cornelis A. , Rendon Augusto , Voss Katrin , Stephens Jonathan ,   HaemGen Consortium, van der Harst Pim , Chambers John C. , Soranzo Nicole , Ouwehand Willem H. , Deloukas Panos
Published: April 2013

Nearly three-quarters of the 143 genetic signals associated with platelet and erythrocyte phenotypes identified by meta-analyses of genome-wide association (GWA) studies are located at non-protein-coding regions. Here, we assessed the role of candidate regulatory variants associated with cell type–restricted, closely related hematological quantitative traits in biologically relevant hematopoietic cell types. We used formaldehyde-assisted isolation of regulatory elements followed by next-generation sequencing (FAIRE-seq) to map regions of open chromatin in three primary human blood cells of the myeloid lineage. In the precursors of platelets and erythrocytes, as well as in monocytes, we found that open chromatin signatures reflect the corresponding hematopoietic lineages of the studied cell types and associate with the cell type–specific gene expression patterns. Dependent on their signal strength, open chromatin regions showed correlation with promoter and enhancer histone marks, distance to the transcription start site, and ontology classes of nearby genes. Cell type–restricted regions of open chromatin were enriched in sequence variants associated with hematological indices. The majority (63.6%) of such candidate functional variants at platelet quantitative trait loci (QTLs) coincided with binding sites of five transcription factors key in regulating megakaryopoiesis. We experimentally tested 13 candidate regulatory variants at 10 platelet QTLs and found that 10 (76.9%) affected protein binding, suggesting that this is a frequent mechanism by which regulatory variants influence quantitative trait levels. Our findings demonstrate that combining large-scale GWA data with open chromatin profiles of relevant cell types can be a powerful means of dissecting the genetic architecture of closely related quantitative traits.
Specific Subunits of Heterotrimeric G Proteins Play Important Roles during Nodulation in Soybean
Authors: Choudhury Swarup Roy , Pandey Sona
Published: April 2013

Heterotrimeric G proteins comprising Gα, Gβ, and Gγ subunits regulate many fundamental growth and development processes in all eukaryotes. Plants possess a relatively limited number of G-protein components compared with mammalian systems, and their detailed functional characterization has been performed mostly in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa). However, the presence of single Gα and Gβ proteins in both these species has significantly undermined the complexity and specificity of response regulation in plant G-protein signaling. There is ample pharmacological evidence for the role of G proteins in regulation of legume-specific processes such as nodulation, but the lack of genetic data from a leguminous species has restricted its direct assessment. Our recent identification and characterization of an elaborate G-protein family in soybean (Glycine max) and the availability of appropriate molecular-genetic resources have allowed us to directly evaluate the role of G-protein subunits during nodulation. We demonstrate that all G-protein genes are expressed in nodules and exhibit significant changes in their expression in response to Bradyrhizobium japonicum infection and in representative supernodulating and nonnodulating soybean mutants. RNA interference suppression and overexpression of specific G-protein components results in lower and higher nodule numbers, respectively, validating their roles as positive regulators of nodule formation. Our data further show preferential usage of distinct G-protein subunits in the presence of an additional signal during nodulation. Interestingly, the Gα proteins directly interact with the soybean nodulation factor receptors NFR1α and NFR1β, suggesting that the plant G proteins may couple with receptors other than the canonical heptahelical receptors common in metazoans to modulate signaling.
Spatiotemporal Secretion of PEROXIDASE36 Is Required for Seed Coat Mucilage Extrusion in Arabidopsis
Authors: Kunieda Tadashi , Shimada Tomoo , Kondo Maki , Nishimura Mikio , Nishitani Kazuhiko , Hara-Nishimura Ikuko
Published: April 2013

The epidermal cells of the Arabidopsis thaliana seed coat, which correspond to the second layer of the outer integument (oi2), contain large quantities of a pectic polysaccharide called mucilage within the apoplastic space beneath the outer periclinal cell wall. Immediately after seed imbibition, the mucilage is extruded and completely envelops the seed in a gel-like capsule. We found that a class III peroxidase family protein, PEROXIDASE36 (PER36), functions as a mucilage extrusion factor. Expression of PER36 occurred only in oi2 cells for a few days around the torpedo stage. A PER36–green fluorescent protein fusion was secreted into the outer cell wall in a polarized manner. per36 mutants were defective in mucilage extrusion after seed imbibition due to the failure of outer cell wall rupture, although the mutants exhibited normal monosaccharide composition of the mucilage. This abnormal phenotype of per36 was rescued by pectin solubilization, which promoted cell wall loosening. These results suggest that PER36 regulates the degradation of the outer cell wall. Taken together, this work indicates that polarized secretion of PER36 in a developmental stage-dependent manner plays a role in cell wall modification of oi2 cells.
Non-Cell-Autonomous Postmortem Lignification of Tracheary Elements inZinnia elegans
Authors: Pesquet Edouard , Zhang Bo , Gorzsás András , Puhakainen Tuula , Serk Henrik , Escamez Sacha , Barbier Odile , Gerber Lorenz , Courtois-Moreau Charleen , Alatalo Edward , Paulin Lars , Kangasjärvi Jaakko , Sundberg Björn , Goffner Deborah , Tuominen Hannele
Published: April 2013

Postmortem lignification of xylem tracheary elements (TEs) has been debated for decades. Here, we provide evidence in Zinnia elegans  TE cell cultures, using pharmacological inhibitors and in intact Z. elegans plants using Fourier transform infrared microspectroscopy, that TE lignification occurs postmortem (i.e., after TE programmed cell death). In situ RT-PCR verified expression of the lignin monomer biosynthetic cinnamoyl CoA reductase and cinnamyl alcohol dehydrogenase in not only the lignifying TEs but also in the unlignified non-TE cells of Z. elegans  TE cell cultures and in living, parenchymatic xylem cells that surround TEs in stems. These cells were also shown to have the capacity to synthesize and transport lignin monomers and reactive oxygen species to the cell walls of dead TEs. Differential gene expression analysis in Z. elegans  TE cell cultures and concomitant functional analysis in Arabidopsis thaliana resulted in identification of several genes that were expressed in the non-TE cells and that affected lignin chemistry on the basis of pyrolysis–gas chromatography/mass spectrometry analysis. These data suggest that living, parenchymatic xylem cells contribute to TE lignification in a non-cell-autonomous manner, thus enabling the postmortem lignification of TEs.