bluuebunny/crossref_metadata_2025 huggingface dataset:
Altered cytological parameters in buccal cells from individuals with mild cognitive impairment and Alzheimer's disease
Authors: François Maxime , Leifert Wayne , Hecker Jane , Faunt Jeffrey , Martins Ralph , Thomas Philip , Fenech Michael
Published: February 2014

Previous studies have shown that mild cognitive impairment (MCI) may be reflective of the early stages of more pronounced neurodegenerative disorders such as Alzheimer's disease (AD). There is a need for a minimally invasive and inexpensive diagnostic to identify those who exhibit cellular pathology indicative of MCI and AD risk so that they can be prioritized for primary preventative measures. The hypothesis was that a minimally invasive approach using cytological markers in isolated buccal mucosa cells can be used to identify individuals of both MCI and AD. An automated buccal cell assay was developed using laser scanning cytometry (LSC) to measure buccal cell type ratios, nuclear DNA content and shape, and neutral lipid content of buccal cells from clinically diagnosed AD (n = 13) and MCI (n = 13) patients prior to treatment compared to age‐ and gender‐matched controls (n = 26). DNA content was significantly higher in all cell types in both MCI (P < 0.01) and AD (P < 0.05) compared with controls mainly due to an increase in >2N nuclei. Abnormal nuclear shape (circularity) was significantly increased in transitional cells in MCI (P < 0.001) and AD (P < 0.01) when compared to controls. In contrast, neutral lipid content (as measured by Oil red O “ORO” staining) of buccal cells was significantly lower in the MCI group (P < 0.05) compared with the control group. The ratio of DNA content/ORO in buccal basal cells for both MCI and AD was significantly higher compared to the control group, with ratios for MCI being approximately 2.8‐fold greater (P < 0.01) and AD approximately 2.3‐fold greater (P < 0.05) than the control group. Furthermore, there was a strong negative correlation between buccal cell DNA content and ORO content in the AD group (r2 = 0.75, P < 0.0001) but not in MCI or controls. The changes in the buccal cell cytome observed in this study could prove useful as potential biomarkers in identifying individuals with an increased risk of developing MCI and eventually AD. © 2014 International Society for Advancement of Cytometry
Revising traditional theory on the link between plant body size and fitness under competition: evidence from old‐field vegetation
Authors: Tracey Amanda J. , Aarssen Lonnie W.
Published: February 2014

The selection consequences of competition in plants have been traditionally interpreted based on a “size‐advantage” hypothesis – that is, under intense crowding/competition from neighbors, natural selection generally favors capacity for a relatively large plant body size. However, this conflicts with abundant data, showing that resident species body size distributions are usually strongly right‐skewed at virtually all scales within vegetation. Using surveys within sample plots and a neighbor‐removal experiment, we tested: (1) whether resident species that have a larger maximum potential body size (MAX) generally have more successful local individual recruitment, and thus greater local abundance/density (as predicted by the traditional size‐advantage hypothesis); and (2) whether there is a general between‐species trade‐off relationship between MAX and capacity to produce offspring when body size is severely suppressed by crowding/competition – that is, whether resident species with a larger MAX generally also need to reach a larger minimum reproductive threshold size (MIN) before they can reproduce at all. The results showed that MIN had a positive relationship with MAX across resident species, and local density – as well as local density of just reproductive individuals – was generally greater for species with smaller MIN (and hence smaller MAX). In addition, the cleared neighborhoods of larger target species (which had relatively large MIN) generally had – in the following growing season – a lower ratio of conspecific recruitment within these neighborhoods relative to recruitment of other (i.e., smaller) species (which had generally smaller MIN). These data are consistent with an alternative hypothesis based on a ‘reproductive‐economy‐advantage’ – that is, superior fitness under competition in plants generally requires not larger potential body size, but rather superior capacity to recruit offspring that are in turn capable of producing grand‐offspring – and hence transmitting genes to future generations – despite intense and persistent (cross‐generational) crowding/competition from near neighbors. Selection for the latter is expected to favor relatively small minimum reproductive threshold size and hence – as a tradeoff – relatively small (not large) potential body size.
Testing the consistency of wildlife data types before combining them: the case of camera traps and telemetry
Authors: Popescu Viorel D. , de Valpine Perry , Sweitzer Rick A.
Published: February 2014

Wildlife data gathered by different monitoring techniques are often combined to estimate animal density. However, methods to check whether different types of data provide consistent information (i.e., can information from one data type be used to predict responses in the other?) before combining them are lacking. We used generalized linear models and generalized linear mixed‐effects models to relate camera trap probabilities for marked animals to independent space use from telemetry relocations using 2 years of data for fishers (Pekania pennanti) as a case study. We evaluated (1) camera trap efficacy by estimating how camera detection probabilities are related to nearby telemetry relocations and (2) whether home range utilization density estimated from telemetry data adequately predicts camera detection probabilities, which would indicate consistency of the two data types. The number of telemetry relocations within 250 and 500 m from camera traps predicted detection probability well. For the same number of relocations, females were more likely to be detected during the first year. During the second year, all fishers were more likely to be detected during the fall/winter season. Models predicting camera detection probability and photo counts solely from telemetry utilization density had the best or nearly best Akaike Information Criterion (AIC), suggesting that telemetry and camera traps provide consistent information on space use. Given the same utilization density, males were more likely to be photo‐captured due to larger home ranges and higher movement rates. Although methods that combine data types (spatially explicit capture–recapture) make simple assumptions about home range shapes, it is reasonable to conclude that in our case, camera trap data do reflect space use in a manner consistent with telemetry data. However, differences between the 2 years of data suggest that camera efficacy is not fully consistent across ecological conditions and make the case for integrating other sources of space‐use data.
Ammonium and Phosphate Quantification in Wastewater by Using a Voltammetric Electronic Tongue
Authors: Campos Inmaculada , Sangrador Ana , Bataller Román , Aguado Daniel , Barat Ramón , Soto Juan , Martínez‐Máñez Ramón
Published: February 2014

Ammonia (NH4N) and orthophosphate (PO4P) quantification in wastewater treatment plants is important due to their implication in the eutrophication process. A voltammetric electronic tongue as a tool for the prediction of ammonia and orthophosphate concentrations from influent and effluent wastewater is proposed herein. An electrochemical study of the response of the ammonium and orthophosphate ions was performed in order to design a suitable waveform for each electrode. Partial Least Squares analysis was used to obtain a correlation between the data from the tongue and the concentrations of ammonia and orthophosphate measured in the laboratory showing good predictive power.
Enantioseparation of new triadimenol antifungal active compounds by electrokinetic chromatography and molecular modeling study of chiral recognition mechanisms
Authors: Li Wuhong , Zhao Liang , Zhang Hai , Chen Xiaofei , Chen Si , Zhu Zhenyu , Hong Zhanying , Chai Yifeng
Published: February 2014

Chiral separation of 12 new triadimenol antifungal active compounds by electrokinetic chromatography and chiral recognition mechanisms by computer‐aided molecular modeling techniques were studied. Seven neutral cyclodextrins were used as chiral selectors. Heptakis‐(2,3,6‐tri‐O‐methyl)‐β‐cyclodextrin (TM‐β‐CD) exhibited a very high enantioselectivity power to 12 active compounds compared to the other testedCDs. The influences of the concentration ofTM‐β‐CD, buffer pH, buffer concentration, applied voltage, and temperature were investigated, respectively. Under the optimum separation conditions, all the 12 active compounds were baseline separated and the resolutions of most compounds were beyond 2.50. The study of the analyte structure–enantioseparation relationships showed that substitutions in the side chains played important roles on enantiomeric separation. By means of computer‐aided molecular modeling softwareDiscoveryStudio 2.5/Sybyl 7.0/Gold 3.0.1, inclusion process betweenTM‐β‐CDand these enantiomers was investigated and their binding energies were calculated. The results suggested that the enantioseparation result related to the difference in binding energy. And the good separation obtained in the presence of theTM‐β‐CDchiral selector was due to the big binding energy difference of two enantiomers with the chiral selector.
Issues and challenges with oil toxicity data and implications for their use in decision making: A quantitative review
Authors: Bejarano Adriana C. , Clark James R. , Coelho Gina M.
Published: February 2014

Aquatic toxicity considerations are part of the net environmental benefit analysis and approval decision process on the use of dispersants in the event of an offshore oil spill. Substantial information is available on the acute toxicity of physically and chemically dispersed oil to a diverse subset of aquatic species generated under controlled laboratory conditions. However, most information has been generated following standard laboratory practices, which do not realistically represent oil spill conditions in the field. The goal of the present quantitative review is to evaluate the use of standard toxicity testing data to help inform decisions regarding dispersant use, recognizing some key issues with current practices, specifically, reporting toxicity metrics (nominal vs measured), exposure duration (standard durations vs short-term exposures), and exposure concentrations (constant vs spiked). Analytical chemistry data also were used to demonstrate the role of oil loading on acute toxicity and the influence of dispersants on chemical partitioning. The analyses presented here strongly suggest that decisions should be made, at a minimum, based on measured aqueous exposure concentrations and, ideally, using data from short-term exposure durations under spiked exposure concentrations. Available data sets are used to demonstrate how species sensitivity distribution curves can provide useful insights to the decision-making process on dispersant use. Finally, recommendations are provided, including the adoption of oil spill–appropriate toxicity testing practices. Environ Toxicol Chem 2014;33:732–742. © 2014 SETAC
Synthetic estrogen directly affects fish biomass and may indirectly disrupt aquatic food webs
Authors: Hallgren Per , Nicolle Alice , Hansson Lars-Anders , Brönmark Christer , Nikoleris Lina , Hyder Murtaza , Persson Anders
Published: February 2014

Endocrine-disrupting chemicals are known to alter the fitness of individual organisms via changes in growth, behavior, and reproduction. It is largely unknown, however, whether these effects cascade through the food web and indirectly affect other, less sensitive organisms. The authors present results from a mesocosm experiment whereby the effects of the synthetic estrogen 17α-ethinylestradiol (EE2) were quantified in pelagic communities. Treatment with EE2 at a concentration of 28 ng/L had no large effects on the pelagic communities composed only of phytoplankton and zooplankton. In communities where planktivorous roach (Rutilus rutilus) were also present, however, EE2 caused a significant reduction in fish biomass. Moreover, zooplankton biomass was higher in the EE2 treatments, suggesting that zooplankton may have been released from fish predation. Hence, the direct effect of EE2 on roach may have cascaded down the food web to produce positive indirect effects on zooplankton. This result was supported in complementary foraging experiments with roach, showing reduced foraging performance after exposure to EE2. Despite the observed negative effect of EE2 on roach and the positive indirect effect on zooplankton, these effects did not cascade to phytoplankton, possibly because only copepods, but not cladocerans—the major grazers in these systems—were released from fish predation. The authors conclude that the known reproductive impairment in fish by EE2 in combination with the disturbed foraging performance observed in the present study may be a disadvantage to fish that may result in increasing abundance or biomass of prey such as zooplankton. Hence, EE2 may have consequences for both the structure and function of freshwater communities. Environ Toxicol Chem 2014;33:930–936. © 2014 SETAC
TGFβ produced by IL‐10 redirected astrocytes attenuates microglial activation
Authors: Norden Diana M. , Fenn Ashley M. , Dugan Allison , Godbout Jonathan P.
Published: February 2014

While there clearly is an intimate relationship between astrocytes and microglia, few studies have examined these potentially dynamic interactions. In this study, cytokine‐mediated communication between microglia and astrocytes under inflammatory conditions was investigated. We have previously shown that activated microglia produce Interleukin (IL)‐10, a regulatory cytokine that plays an important role in resolving neuroinflammation. Nonetheless, the mechanism by which IL‐10 attenuates pro‐inflammatory cytokine expression in the brain is unclear. Here, we show that IL‐10 redirected astrocytes regulate the activation of microglia in a transforming growth factor (TGF)‐β dependent manner. In support of this concept, astrocytes in the brain maintained higher IL‐10 receptor (IL‐10R1) expression and primary astrocytes in culture were markedly more sensitive to the anti‐inflammatory effects of IL‐10 compared with microglia. Moreover, studies using primary cultures and an astrocyte‐microglia coculture system revealed that astrocytes mediated the anti‐inflammatory effects of IL‐10 on microglia through the production of TGFβ. For instance, only when astrocytes were present did IL‐10 stimulation reduce the expression of IL‐1β and increase expression of anti‐inflammatory mediators fractalkine receptor (CX3CR1) and interleukin 4 receptor‐α (IL‐4Rα) in microglia. Importantly, these IL‐10‐astrocyte dependent effects on microglia were blocked by a TGFβ inhibitor. Furthermore, inhibition of TGFβ signaling in the brain resulted in prolonged sickness behavior and amplified pro‐inflammatory cytokine expression in mice challenged with lipopolysaccharide. Taken together, IL‐10 stimulated the production of TGFβ by astrocytes, which in turn, attenuated microglial activation. Overall, these findings provide novel insight into the mechanisms by which astrocytes modulate microglia under inflammatory conditions. GLIA 2014;62:881–895
NOS2 expression is restricted to neurons in the healthy brain but is triggered in microglia upon inflammation
Authors: Béchade Catherine , Colasse Sabrina , Diana Marco A. , Rouault Martin , Bessis Alain
Published: February 2014

Nitric oxide (NO) is a diffusible second messenger with a great variety of functions in the brain. NO is produced by three isoforms of NO synthase (NOS), NOS1, NOS2, and NOS3. Although broad agreement exists regarding the expression of NOS1 and NOS3 in neurons and endothelial cells, the pattern of NOS2 expression is still controversial and remains elusive. We have now generated a novel transgenic mouse that expresses the fluorescent reporter tdTomato and the CRE recombinase under the control of the Nos2 gene regulatory regions. Such tool allows the reliable tracking of NOS2 expression in tissue and further unravels episodes of transient NOS2 expression. Using this transgenic mouse, we show that in the healthy brain, NOS2 is only transiently expressed in neurons scattered in the piriform and entorhinal cortex, the amygdaloid nuclei, the medial part of the thalamus, the hypothalamus, the dentate gyrus, and the cerebellum. NOS2 expression was rarely detected in microglia. We further show that inflammation, induced by intracerebral injection of LPS and IFNγ, triggers transient expression of NOS2 in microglia but not in neurons. This novel transgenic tool has thus allowed us to clarify the NOS2 expression pattern and its differential profile in neurons and microglia in healthy and inflammatory conditions. GLIA 2014;62:956–963
Emotional fronto‐cingulate cortex activation and brain derived neurotrophic factor polymorphism in premenstrual dysphoric disorder
Authors: Comasco Erika , Hahn Andreas , Ganger Sebastian , Gingnell Malin , Bannbers Elin , Oreland Lars , Wikström Johan , Epperson C. Neill , Lanzenberger Rupert , Sundström‐Poromaa Inger
Published: February 2014

Premenstrual dysphoric disorder (PMDD) is the prototypical sex‐specific disorder in which symptom onset and offset require a particular hormonal milieu and for which there is moderate heritability. The present study investigated brain emotion processing in PMDD and healthy controls, as well as functional polymorphisms in two candidate genes for PMDD, the serotonin transporter (5‐HTT) and brain derived neurotrophic factor (BDNF). The 5‐HTT linked polymorphic region (5‐HTTLPR) and BDNF Val66Met polymorphisms were genotyped in 31 patients with PMDD and 31 healthy controls. A subset of 16 patients and 15 controls participated in two functional magnetic resonance imaging‐sessions performing an emotion processing task; once in the mid‐follicular, and once in the late luteal phase which corresponds with maximum severity of mood symptoms. Genotypes were not directly associated with PMDD. A main effect of group was found in the whole brain analysis, with patients having lower activation of the pre‐genual anterior cingulate and ventro‐medial prefrontal cortex, independent of menstrual cycle phase. Post‐hoc functional ROI analyses in the fronto‐cingulate cluster showed no effect of 5‐HTTLPR genotype but a genotype‐by‐group‐by‐phase interaction effect of BDNF Val66Met. Women with PMDD who were carriers of the Met‐allele had lower fronto‐cingulate cortex activation in the luteal phase compared to Met‐allele carrying controls. The results provide suggestive evidence of impaired emotion‐induced fronto‐cingulate cortex activation in PMDD patients. Although limited by a small sample, the potential influence of BDNF Val66Met in PMDD is in line with preclinical findings. Hum Brain Mapp 35:4450–4458, 2014. © 2014 The Authors. Human Brain Mapping Published by Wiley Periodicals, Inc.
Network connectivity abnormality profile supports a categorical‐dimensional hybrid model of ADHD
Authors: Elton Amanda , Alcauter Sarael , Gao Wei
Published: February 2014

Attention‐deficit/hyperactivity disorder (ADHD) is characterized by inattention, hyperactivity, and impulsivity, but there is no consensus regarding whether ADHD exists on the extreme end of a continuum of normal behavior or represents a discrete disorder. In this study, we sought to characterize both the categorical and dimensional variations in network functional connectivity in order to identify neural connectivity mechanisms of ADHD. Functional connectivity analyses of resting‐state fMRI data from 155 children with ADHD and 145 typically developing children (TDC) defined the dorsal attention network (DA), default mode network (DM), salience processing network (SAL) and executive control network (CON). Regional alterations in connectivity associated with categorical diagnoses and dimensional symptom measures (inattention and hyperactivity/impulsivity) as well as their interaction were systematically characterized. Dimensional relationships between symptom severity measures and functional connectivity that did not differ between TDC and children with ADHD were observed for each network, supporting a dimensional characterization of ADHD. However, categorical differences in functional connectivity magnitude between TDC and children with ADHD were detected after accounting for dimensional relationships, indicating the existence of categorical mechanisms independent of dimensional effects. Additionally, differential dimensional relationships for TDC versus ADHD children demonstrated categorical differences in brain–behavior relationships. The patterns of network functional organization associated with categorical versus dimensional measures of ADHD accentuate the complexity of this disorder and support a dual characterization of ADHD etiology featuring both dimensional and categorical mechanisms. Hum Brain Mapp 35:4531–4543, 2014. © 2014 Wiley Periodicals, Inc.
Estimating the Benefits of Public Health Policies that Reduce Harmful Consumption
Authors: Ashley Elizabeth M. , Nardinelli Clark , Lavaty Rosemarie A.
Published: February 2014

For products such as tobacco and junk food, where policy interventions are often designed to decrease consumption, affected consumers gain utility from improvements in lifetime health and longevity but also lose utility associated with the activity of consuming the product. In the case of anti‐smoking policies, even though published estimates of gross health and longevity benefits are up to 900 times higher than the net consumer benefits suggested by a more direct willingness‐to‐pay estimation approach, there is little recognition in the cost‐benefit and cost‐effectiveness literature that gross estimates will overstate intrapersonal welfare improvements when utility losses are not netted out. This paper presents a general framework for analyzing policies that are designed to reduce inefficiently high consumption and provides a rule of thumb for the relationship between net and gross consumer welfare effects: where there exists a plausible estimate of the tax that would allow consumers to fully internalize health costs, the ratio of the tax to the per‐unit long‐term cost can provide an upper bound on the ratio of net to gross benefits. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
Impact of glyphosate and glyphosate‐based herbicides on the freshwater environment
Authors: Annett Robert , Habibi Hamid R. , Hontela Alice
Published: February 2014

Glyphosate [N‐(phosphonomethyl) glycine] is a broad spectrum, post emergent herbicide and is among the most widely used agricultural chemicals globally. Initially developed to control the growth of weed species in agriculture, this herbicide also plays an important role in both modern silviculture and domestic weed control. The creation of glyphosate tolerant crop species has significantly increased the demand and use of this herbicide and has also increased the risk of exposure to non‐target species. Commercially available glyphosate‐based herbicides are comprised of multiple, often proprietary, constituents, each with a unique level of toxicity. Surfactants used to increase herbicide efficacy have been identified in some studies as the chemicals responsible for toxicity of glyphosate‐based herbicides to non‐target species, yet they are often difficult to chemically identify. Most glyphosate‐based herbicides are not approved for use in the aquatic environment; however, measurable quantities of the active ingredient and surfactants are detected in surface waters, giving them the potential to alter the physiology of aquatic organisms. Acute toxicity is highly species dependant across all taxa, with toxicity depending on the timing, magnitude, and route of exposure. The toxicity of glyphosate to amphibians has been a major focus of recent research, which has suggested increased sensitivity compared with other vertebrates due to their life history traits and reliance on both the aquatic and terrestrial environments. This review is designed to update previous reviews of glyphosate‐based herbicide toxicity, with a focus on recent studies of the aquatic toxicity of this class of chemicals. Copyright © 2014 John Wiley & Sons, Ltd.
Modeling and simulation of bone mineral density response from a phase 2 study of ONO‐5334, a new cathepsin K inhibitor, to support dose selection in osteoporosis
Authors: Hasegawa Chihiro , Kastrissios Helen , Monteleone Jonathan , Ohno Tomoya , Umemura Takeo , Ohyama Michiyo , Nagase Shinichi , Small Maria , Deacon Steve , Ogawa Mikio , Ieiri Ichiro
Published: February 2014

ONO‐5334, a selective inhibitor of cathepsin K, is a potential new treatment for osteoporosis. The objectives of this modeling study were to (1) develop exposure–response (E–R) models to relate ONO‐5334 exposure to bone mineral density (BMD), (2) predict BMD responses to various doses of ONO‐5334 for both immediate release tablet (IRT) and sustained release tablet (SRT) formulations where only BMD response after administration of IRT had been studied to date, (3) inform selection of appropriate formulation/dose using simulation for future clinical trials. A population pharmacokinetic (PK) model was developed to simultaneously analyze data for both IRT and SRT. The exposure metrics at steady state were estimated by post hoc Bayesian prediction using the final population PK model. E–R models were developed using dose‐ranging data with only IRT from postmenopausal females with osteoporosis. Based on the developed model, lumbar spine and total hip BMD after administration of ONO‐5334 SRT as well as IRT were simulated. The simulation results showed that ONO‐5334 SRT should provide comparable BMD responses at a lower dose relative to IRT (a finding consistent with the results from a previous population PK–PD modeling study with bone resorption markers).
Super‐resolution imaging with stochastic single‐molecule localization: Concepts, technical developments, and biological applications
Authors: Oddone Anna , Vilanova Ione Verdeny , Tam Johnny , Lakadamyali Melike
Published: February 2014

Light microscopy has undergone a revolution with the advent of super‐resolution microscopy methods that can surpass the diffraction limit. These methods have generated much enthusiasm, in particular with regards to the new possibilities they offer for biological imaging. The recent years have seen a great advancement both in terms of new technological developments and exciting biological applications. Here, we review some of the important milestones in the field and highlight some recent biological applications. Microsc. Res. Tech. 77:502–509, 2014. © 2014 Wiley Periodicals, Inc.
Mechanisms of silicon sputtering and cluster formation explained by atomic level simulations
Authors: Barry Peter R. , Philipp Patrick , Wirtz Tom , Kieffer John
Published: February 2014

In low‐energy secondary ion MS, collision cascades result in rare sputter events or unfavourably low sputter yields. To better identify the origin of emission products generated by low‐energy ion impacts, we carried out molecular dynamics simulations of the underlying collision cascades, using a reactive force field that accounts for the dynamic breaking and forming of bonds. A detailed explanation of the cluster formation and ejection processes for atomic oxygen and also atomic silicon bombardment of Si (100) is given for comparison. Copyright © 2014 John Wiley & Sons, Ltd.
MALDI‐TOF mass spectrometry, an efficient technique for in situ detection and characterization of actinomycins
Authors: Vater Joachim , Crnovčić Ivana , Semsary Siamak , Keller Ullrich
Published: February 2014

An extensive study of actinomycins was performed using matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐TOF MS). Actinomycins represent a well‐known family of peptidolactone chromopeptides with potent cytostatic and antibiotic properties. Using five well‐characterized streptomycete strains, we introduced MALDI‐TOF MS as an efficient technique for rapid in situ detection of actinomycins in surface extracts of cells picked from agar plates. By this procedure, actinomycin complexes can be investigated with high sensitivity and accuracy in a minimum of time. These studies were complemented by mass spectrometric investigation of actinomycins obtained from culture filtrate extracts and purified by high‐performance liquid chromatography to detect yet unknown actinomycin species. By feeding experiments, C‐demethyl‐actinomycins from Streptomyces chrysomallus and Streptomyces parvulus as well as hemi‐actinomycins from Streptomyces antibioticus lacking one of the two pentapeptide lactone rings were isolated and characterized as novel variants for structure–activity relationship studies. Structural characterization of the investigated actinomycins was performed by post source decay MALDI‐TOF MS. The specific features of the fragmentation patterns of the protonated and cationized forms of selected actinomycins were investigated in detail. Copyright © 2014 John Wiley & Sons, Ltd.
How far can ion trap miniaturization go? Parameter scaling and space‐charge limits for very small cylindrical ion traps
Authors: Tian Yuan , Higgs Jessica , Li Ailin , Barney Brandon , Austin Daniel E.
Published: February 2014

A broad effort is underway to make radiofrequency (RF) ion trap mass spectrometers small enough for portable chemical analysis. A variety of trap geometries and fabrication approaches are under development from several research groups. A common issue is the reduced trapping capacity in smaller traps, with the associated reduction in sensitivity. This article explores the key variables that scale with trap size including RF voltage, frequency, electrical capacitance, power and pseudopotential well depth. High‐field electric breakdown constrains the maximum RF voltages used in smaller ion traps. Simulations show the effects of space charge and the limits of trapping capacity as a function of trap dimensions for cylindrical ion traps down to the micrometer level. RF amplitudes that scale as the1/3, 1/2 and 2/3 power of trap radius, r0, were studied. At a fixed level of performance, the number of analyzable ions scales as r0n, with n ranging from 1.55 to 1.75 depending on the choice of voltage scaling. The implications for miniaturized ion trap mass spectrometry are discussed. Copyright © 2014 John Wiley & Sons, Ltd.
Semi‐analytical computation of a quasi‐static field induced by a 3D eddy current probe scanning a 2D layered conductor with parallel rough interfaces
Authors: Caire F. , Prémel D. , Granet G.
Published: February 2014

This paper deals with the fast computation of the quasi‐static fields induced in a conductor with a locally perturbed shape along the longitudinal axis and extruded along the transversal one. Besides, the material is composed of several homogeneous layers with parallel faces. The method used here is based on writing Maxwell's equations in a curvilinear system, which leads to a more simple expression of boundary conditions. The validity of this method for the computation of quasi‐static fields induced by an eddy current probe in a conductive half‐space with a rough surface has been proved recently, and we propose here to complete this innovative formalism in order to solve an eddy current non‐destructive testing (ECNDT) configuration with a rough surface conductive medium composed of several homogeneous layers with parallel faces. This extension allows to tackle new ECNDT configurations such as homogeneous media constituted by rough interfaces. Moreover, it provides sufficient solutions for non‐homogeneous conductive parts presenting a depth‐varying (i.e., along the direction of the normal local vector with respect to the surface) material property, which can be approximated by a piecewise constant function by introducing multiple thin homogeneous layers. Copyright © 2014 John Wiley & Sons, Ltd.
Universal method for the synthesis of arbitrary polarization states radiated by a nanoantenna
Authors: Rodríguez‐Fortuño Francisco J. , Puerto Daniel , Griol Amadeu , Bellieres Laurent , Martí Javier , Martínez Alejandro
Published: February 2014

Optical nanoantennas efficiently convert confined optical energy into free‐space radiation. The polarization of the emitted radiation depends mainly on nanoantenna shape, so it becomes extremely difficult to manipulate it unless the nanostructure is physically altered. Here, a simple way is demonstrated to synthetize the polarization of the radiation emitted by a single nanoantenna so that every point on the Poincaré sphere becomes attainable. The nanoantenna consists of a single scatterer created on a dielectric waveguide and fed from its both sides so that the polarization of the emitted optical radiation is controlled by the amplitude and phase of the feeding signals. The nanoantenna is created on a silicon chip using standard top‐down nanofabrication tools, but the method is universal and can be applied to other materials, wavelengths and technologies. This work will open the way towards the synthesis and control of arbitrary polarization states in nano‐optics.
The lubrication effect of hyaluronic acid and chondroitin sulfate on the natural temporomandibular cartilage under torsional fretting wear
Authors: Wu Ting‐ting , Gan Xue‐qi , Cai Zhen‐bing , Zhu Min‐hao , Qiao Meng‐ting , Yu Hai‐yang
Published: February 2014

The aim of this study is to investigate the lubrication of hyaluronic acid (HA) and chondroitin sulfate (CS) on the condylar cartilage of the temporomandibular joint. The wear behaviour of bovine condyle cartilage was explored against a zirconia ball with different lubrications under torsional fretting mode. The worn cartilage morphologies were observed using scanning electron microscopy and hemotoxylin and eosin staining. The results indicated that HA or CS could significantly lower the friction torque and dissipated energy of fretting interface and reduce the damage of the articular cartilage surface compared to the control (phosphate‐buffered saline). The mixture (HA and CS) could provide better protection for the cartilage layer. Absence of good lubrication in overloading torsional fretting process caused excessive cartilage wear. High concentration and high molecular weight HA or CS acted as good boundary lubricants, and the lubrication effect of their mixture was better due to their synergistic function. Copyright © 2014 John Wiley & Sons, Ltd.
Effect of the pretransplant serum sodium concentration on outcomes following liver transplantation
Authors: Leise Michael D. , Yun Byung Cheol , Larson Joseph J. , Benson Joanne T. , Yang Ju Dong , Therneau Terry M. , Rosen Charles B. , Heimbach Julie K. , Biggins Scott W. , Kim Ray W.
Published: February 2014

Hyponatremia is associated with an increased risk of mortality on the liver transplantation (LT) waiting list. Although the incorporation of the serum sodium (Na) level into the Model for End-Stage Liver Disease score may reduce wait-list mortality, concerns remain about a potential association between pre-LT hyponatremia and decreased post-LT survival. Furthermore, the relationship between pre-LT hypernatremia and post-LT survival remains unexplored. The purpose of this study was to investigate the impact of the entire spectrum of pre-LT serum Na levels on post-LT outcomes. We identified 19,537 patients from 2003 to 2010 for whom serum Na levels immediately before LT were available. The patients were divided into 3 groups [hyponatremic (Na ≤ 130 mEq/L), normonatremic (Na = 131-145 mEq/L), and hypernatremic (Na > 145 mEq/L)], and their post-LT outcomes were compared. There was no difference in in-hospital mortality or 90-day survival between patients with hyponatremia and patients with normonatremia. A fraction of the patients (2.4%) had hypernatremia, which was associated with increased in-hospital mortality (11.2% versus 4.2%, P < 0.001) and diminished 90-day survival (86.4% versus 94.0.%, P < 0.001). After adjustments for important clinical variables, the association of pre-LT hypernatremia with posttransplant mortality remained significant with a hazard ratio of 1.13 for each unit increase in the Na level > 145 mEq/L (P < 0.001). The duration of the hospitalization after LT was significantly longer for hypernatremic patients (P < 0.001). In conclusion, hyponatremia per se does not affect post-LT survival. Pre-LT hypernatremia is a highly significant risk factor for post-LT mortality. Liver Transpl 20:687-697, 2014. © 2014 AASLD.
Layer‐by‐Layer Coated PLA Nanoparticles with Oppositely Charged β‐Cyclodextrin Polymer for Controlled Delivery of Lipophilic Molecules
Authors: El Fagui Amani , Wintgens Véronique , Gaillet Christine , Dubot Pierre , Amiel Catherine
Published: February 2014

The preparation of novel nanoparticles is described, which consist of a poly(lactic acid) (PLA) core obtained by the nanoprecipitation method with a shell made of oppositely charged β‐cyclodextrin polymer (poly‐β‐CD) assembled using the layer‐by‐layer technique. Characterization of these nanoparticles is accomplished through dynamic light scattering, ζ‐potential measurements, X‐ray photoelectron spectroscopy and electron microscopy. The release of a loaded lipophilic molecule, benzophenone (BP), is mainly controlled by diffusion of BP and by its host–guest interaction with the β‐CD cavities of the adsorbed poly‐β‐CD. Increasing the number of poly‐β‐CD layers results in a better control of the release through the partition equilibrium between free BP and BP included in the cavities inside the multilayers.

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Solubility and electrochemical properties of chemically modified polyaniline‐gold/camphor sulfonic acid composites
Authors: Basavaraja C. , Jung Gyu Ho , Huh Do Sung
Published: February 2014

Polyaniline nanocomposites encapsulating gold nanoparticles on camphor sulfonic acid (CSA) surface were prepared via the polymerization of aniline hydrochloride with different concentrations of CSA using HAuCl4 as oxidant. The synthesized composites were characterized by Fourier transform infrared spectroscopy and UV–visible spectroscopy. Surface morphology was studied by scanning electron microscopy and transmission electron microscopy. The embedded crystallinity of the composites was investigated by X‐ray diffraction analysis. The solubility of the nanocomposites was studied using water, N‐methyl‐2‐pyrrolidinone, chloroform, and dimethylformamide solvents. The room temperature direct current conductivity of the composites was also observed in solution state. Electrical property of the composites was examined using cyclic voltammetric measurements at room temperature. The fabricated polymer nanocomposites with better solubility in water and some organic solvents will have various applications in electrical devices and biosensors. POLYM. COMPOS., 36:245–252, 2015. © 2014 Society of Plastics Engineers
Preparation and properties of 8‐hydroxyquinoline aluminum quinoline/polyaniline core–shell composite
Authors: Li Tingxi , Lv Mengyao , Li Huimin , Liu Yun , Li Kun , Chen Quanliang , Wang Yanmin , Zhang Qiang
Published: February 2014

Polyaniline (PANI) as an excellent conducting polymer material has been used to synthesize 8‐hydroxyquinoline aluminum quinoline/polyaniline (Alq3/PANI) composites with core‐shell structure which is expected to form ultra‐conjugated system between core/shell and be used as organic electronic material. Alq3 was coated by sodium dodecyl benzene sulfonate doped PANI via in situ polymerization of aniline on the surface of Alq3. The morphology, structure crystallinity, and thermal stability of synthesized composite were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, and thermal gravimetric analysis. Results indicated that the composite is core‐shell structure and exhibits good thermal stability. Conductivity of composite was investigated and showed that Alq3 as core in composite which improved the conductivity of pristine PANI, indicating that electronic interactive effect was formed between core and shell. POLYM. COMPOS., 36:272–277, 2015. © 2014 Society of Plastics Engineers
Heteromer score—using internal standards to assess the quality of proteomic data
Authors: Rogowska‐Wrzesinska Adelina , Wrzesinski Krzysztof , Fey Stephen J.
Published: February 2014

In the cell, the majority of proteins exist in complexes. Most of these complexes have a constant stoichiometry and thus can be used as internal standards. In this rapid communication, we show that it is possible to calculate a correlation coefficient that reflects the reproducibility of the analytical approach used. The abundance of one subunit in a heterodimer is plotted against the abundance of the other, and this is repeated for all subunits in all heteromers found in the data set. The correlation coefficient obtained (the “heteromer score”) is a new bioinformatic tool that is independent of the method used to collect the data, requires no special sample preparation and can be used retrospectively on old datasets. It can be used for quality control, to indicate when a change becomes significant or identify complexes whose stoichiometry has been perturbed during the experiment.
High‐Tg and low‐dielectric epoxy thermosets based on a propargyl ether‐containing phosphinated benzoxazine
Authors: Lin Ching Hsuan , Huang Chu Ming , Wong Tung I. , Chang Hou Chien , Juang Tzong Yuan , Su Wen Chiung
Published: February 2014

A propargyl ether‐containing benzoxazine (4) was prepared from a potassium carbonate‐catalyzed nucleophilic substitution of propargyl bromide and a phenolic OH‐containing benzoxazine (3), which was prepared from 1‐(4‐hydroxyphenyl)‐1‐(4‐aminophenyl)‐1‐(6‐oxido‐6H ‐dibenz <1,2> oxaphosphorin‐6‐yl)ethane (1) by a three‐step procedure. The curing reactions of (4) were monitored by IR and DSC. A reaction mechanism was proposed based on the observation. Benzoxazines (3) and (4) were applied as epoxy curing agents. The microstructure and the structure‐property relationship of the resulting thermosets are discussed. The double‐strand structure in (4)‐cured epoxy thermosets afforded higher crosslinking density, and led to higher thermal properties. In addition, the (4)‐cured epoxy thermosets possess half the amount of highly polar hydroxyl groups than those of the (3)‐cured epoxy thermosets, resulting in a lower dielectric constant, dissipation factor, and water absorption. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1359–1367
Influence of the electrostatic interactions on thermophysical properties of polyimides: Molecular‐dynamics simulations
Authors: Falkovich Stanislav G. , Lyulin Sergey V. , Nazarychev Victor M. , Larin Sergey V. , Gurtovenko Andrey A. , Lukasheva Natalia V. , Lyulin Alexey V.
Published: February 2014

Revealing the way of how modification of the chemical structure of a polymer affects its macroscopic physical properties offers an opportunity to develop novel polymer materials with pre‐defined characteristics. To address this problem two thermoplastic polyimides, ULTEM™ and EXTEM™, were simulated with small difference in chemical structures of monomer units, namely, the phenyl ring in ULTEM™ was replaced by the diphenylsulphone group in EXTEM™. It is shown that such a small modification results in a drastic difference of the thermal properties: the glass transition temperature of EXTEM™ is higher than that of ULTEM™. Our molecular‐dynamics simulations clearly demonstrated that it is the electrostatic interactions that are responsible for the observed difference in thermal properties of ULTEM™ and EXTEM™: large partial charges of the sulphone group in the EXTEM™ lead to strong dipole–dipole intra‐ and intermolecular interactions and correspondingly to an elevated glass transition temperature. © 2014 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014, 52, 640–646
Shotgun MS proteomic analysis of bronchoalveolar lavage fluid in normal subjects
Authors: Nguyen Elizabeth V. , Gharib Sina A. , Schnapp Lynn M. , Goodlett David R.
Published: February 2014

We provide a review of proteomic techniques used to characterize the bronchoalveolar lavage fluid (BALF) proteome of normal healthy subjects. Bronchoalveolar lavage (BAL) is the most common technique for sampling the components of the alveolar space. The proteomic techniques used to study normal BALF include protein separation by 2DE, whereby proteins were identified by comparison to a reference gel as well as high pressure liquid chromatography (HPLC)‐MS/MS, also known as shotgun proteomics. We summarize recent progress using shotgun MS technologies to define the normal BALF proteome. Surprisingly, we find that despite advances in shotgun proteomic technologies over the course of the last 10 years, which have resulted in greater numbers of proteins being identified, the functional landscape of normal BALF proteome was similarly described by all methods examined.
Transient photoluminescence of aluminum‐rich (Al,Ga)N low‐dimensional structures
Authors: Lefebvre Pierre , Brimont Christelle , Valvin Pierre , Gil Bernard , Miyake Hideto , Hiramatsu Kazumasa
Published: February 2014

Light‐emitting devices based on high‐Al content (Al,Ga)N suffer from high densities of dislocations or other point defects, counterbalanced by the carrier localization arising from disorder in the ternary alloy. One way to improve the internal quantum efficiency is the controlled Si‐doping of AlxGa1−xN/AlyGa1−yN multi‐quantum wells, which was assigned to the reduction of point defects by reduction of internal strains, for some ideal concentration of Si. Time‐resolved photoluminescence (TR‐PL) can be used [S. F. Chichibu et al., Appl. Phys. Lett. 99, 051902 (2011)] to try and correlate the observed PL time‐decays with the density of defects, in relation with the nonradiative recombination probability of photoexcited carriers. We present TR‐PL studies of MOVPE‐grown Si‐doped AlxGa1−xN/AlyGa1−yN multi‐quantum wells with typical values of x = 0.6 and y = 0.7 and of AlxGa1−xN epilayers with x up to 0.86. High‐Al content MQWs and epilayers exhibit similar bi‐exponential PL decay dynamics, with the slower component rapidly quenched when T is increased. The fast decay component remains in the nanosecond range at all temperatures and the PL intensity loss is limited by carrier localization.
Pulsed gas aggregation for improved nanocluster growth and flux
Authors: Drache Steffen , Stranak Vitezslav , Berg Florian , Hubicka Zdenek , Tichy Milan , Helm Christiane A. , Hippler Rainer
Published: February 2014

Growth of Cu nanoparticles in a pulsed gas aggregation cluster source was studied. The cluster growth is enhanced by an energy transport inside the aggregation chamber fed by argon that is delivered in short pulses repeated with low frequency. The effect of pressure, varied during the pulse, on the cluster growth was estimated from time‐resolved measurements of mass/size cluster distribution. The cluster mass and the cluster production well correlate with pressure changes. Several stages of cluster growth during the gas‐pulse were recognized. Not only larger clusters but also significantly enhanced particle and mass fluxes were observed.