bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear Detection Methods and Instrumentation
Authors: Tsechanski A.
Published: September 2014

Nuclear detectors and associated electronics are among the most important components of analytical chemistry involving nuclear methods. Historically, the first and simplest particle detectors were gas‐filled counters using an electric field to collect the free charge carriers, electrons and ions, produced in the counter by ionizing radiation. These detectors include ion chambers, proportional counters and Geiger counters. The charge created at the proportional counter is directly proportional to the energy deposited in the detector by a nuclear particle and, therefore, this kind of detector can be used for energy measurements of nuclear radiation (nuclear spectrometry). The main disadvantage of gas‐filled detectors is their low efficiency for γ‐rays. This is because the gas detection medium is low in density. From this point of view, solid detectors are considerably more advantageous. Of these detectors, the scintillation counter is one of the earliest and most widely used detectors of nuclear radiation. It consists of a detection medium (inorganic or organic scintillator) and a photomultiplier tube (PMT). The incident particle enters the scintillator and interacts with its atoms, raising them to excited states. De‐excitation follows very rapidly by emission of light photons. The emitted light photons are multiplied in the PMT, resulting in an output pulse of up to several volts. The high efficiency scintillation detectors are widely used in instrumental analytical chemistry including neutron activation analysis (NAA), both prompt neutron activation analysis (PNAA) and delayed neutron activation analysis (DNAA), and in X‐ray fluorescence analysis (XRFA). Contemporary high‐resolution γ‐spectrometry is based on solid‐state ionization chambers. Only after the successful development of the technology for production of highly purified single crystals of germanium (Ge) and silicon (Si) did it become possible to develop Ge‐ and Si‐based solid‐state detectors by forming reverse‐biased junctions and cooling the semiconductor to liquid nitrogen temperature (77 K). The most prominent feature of the semiconductor detectors is their excellent energy resolution and availability of large crystals with relative efficiencies up to 150% and beyond compared with a standard NaI(Tl) detector. High‐resolution γ‐ray spectrometry is widely used in evaluation of γ‐emitting radioactive nuclides in various samples, in NAA, in a high‐sensitivity particle‐induced X‐ray emission (PIXE) method and others. Nuclear detectors provide a variety of information on detected radiation (type of the radiation, its energy, timing and position data, etc.) in the form of electronic signals. To obtain this information, the signal must be processed by the appropriate nuclear electronic system, which includes power supply, preamplifier, main amplifier and multichannel analyzer (MCA) for digital processing of the analog signals.
Surface‐enhanced Raman Spectroscopy (SERS): Protein Application
Authors: Chen Lei , Cai Linjun , Ruan Weidong , Zhao Bing
Published: September 2014

This article outlines the recent progress in surface‐enhanced Raman spectroscopy (SERS)‐based biological applications, especially in the study of proteins. SERS is a specific Raman spectroscopic technique that provides enhanced Raman signals (several orders of magnitude greater than normal) for numerous Raman‐active analyte molecules adsorbed onto rough metal surfaces. SERS is a sensitive, selective, and versatile technique, and it lends itself readily to fast data acquisition. Therefore, SERS has undergone rapid development because of numerous technical advances in both instrumentation and methods of data analysis and a vast proliferation and combination of basic techniques for its multiple biological applications. This article highlights several representative areas in biology where SERS could be employed. Some of the biological applications of SERS are more developed, whereas others are in their initial stages of development (in laboratories). This article discusses the recent developments in SERS‐based quantitative analysis: (i) directly with different substrates (e.g. biomolecules on electrodes, colloidal particles, and periodic pattern structure and tip‐based substrates) and (ii) indirectly with different types of sensors (e.g. immunogold‐, enzymatic‐, reagent‐, and Raman‐active nanomaterial‐based sensors). Furthermore, SERS‐based techniques are advantageous for obtaining valuable information on protein–protein, protein–ligand, and protein–drug recognitions via spectral differences among molecular bridges. SERS‐based techniques show considerable promise for qualitative and/or quantitative analyses of biological systems.
MEMS‐ andMOEMS‐Based Near‐Infrared Spectrometers
Authors: Antila Jarkko , Tuohiniemi Mikko , Rissanen Anna , Kantojärvi Uula , Lahti Markku , Viherkanto Kai , Kaarre Marko , Malinen Jouko
Published: September 2014

The trend in near‐infrared (NIR) spectroscopy is to go toward on‐site, in‐field, on‐the‐go applications with calibration‐free instruments and off‐the‐shelf chemometrics software. Micro‐electro‐mechanical systems (MEMS) and micro‐opto‐electro‐mechanical systems (MOEMS) represent manufacturing techniques and components, capable of enabling highly miniaturized, robust, and low‐cost sensors and actuators. This article presents commonMEMSandMOEMSmanufacturing techniques and gives an insight into the demands ofNIRspectroscopic applications. The main instrument categories are covered by a short theory followed by examples. Most thoroughly handled topics are Fourier transform spectrometers (FTSs), Fabry–Perot interferometers (FPIs), and dispersive spectrometers. Two other categories are also separately presented, namely light modulator systems and tunableMEMSlight sources. We give an overview onNIRspectroscopy and its special requirements regarding the realization ofMEMSspectrometers.
Scree Test
Authors: B. D'agostino Ralph , Russell Heidy K.
Published: September 2014

The scree test is a test for determining the number of factors to retain in a factor analysis or principal components analysis. The scree test involves plotting the eigenvalues in descending order of their magnitude against their factor numbers and determining where they level off. The break between the steep slope and a leveling off indicates the number of meaningful factors, different from random error. The technique is illustrated and compared with alternative techniques for determining the number of factors to retain.
Dendrogram
Authors: CaliŃski Tadeusz
Published: September 2014

The term “dendrogram” is used in numerical taxonomy for any graphical drawing or diagram giving a treelike description of a taxonomic system. More generally, a dendrogram is a two‐dimensional diagram representing a tree of relationships, whatever their nature.

The representation of a taxonomic system by a dendrogram is particularly suitable in connection with a cluster analysis applied to investigate the structure of the corresponding operational taxonomic units, such as individual patients or case histories initially used to construct disease classifications. This becomes apparent when it is desirable to interpret the results of the analysis in terms of a natural nonoverlapping taxonomic hierarchy. The usual basis for a cluster analysis is a resemblance matrix, its rows and columns referring to the operational taxonomic units, and its entries being the estimates of the resemblances between the corresponding units.

Examples of dendrograms and methods of their presentation are described in many textbooks on numerical taxonomy and cluster analysis.

Among the various clustering methods, the single linkage cluster analysis is particularly relevant to a dendrogram representation.
Spearman Rank Correlation: Overview
Authors: Zar Jerrold H.
Published: September 2014

In a nonparametric (distribution‐free) approach to the correlation between two sets of measurements made on the same individuals, each set may be ranked in order of magnitude. The standard (Pearson) product‐moment correlation coefficient is calculated on the two sets of ranks. Simple formulae are available, and adjustments are made for tied ranks. Test and estimation procedures are described. The relationship with the Kendall rank correlation coefficient is discussed.
Summary Measure Analysis of Longitudinal Data
Authors: Everitt Brian S.
Published: September 2014

There are a variety of methods of analysis for longitudinal data, but one of the most straightforward is the use of summary measures that essentially reduce the problem from multivariate to univariate. Once a suitable summary measure has been chosen, analysis usually involves simple techniques such as
t
Tests, analysis of variance, or their nonparametric analogues.
Principal Component Analysis
Authors: Jolliffe Ian
Published: September 2014

When large multivariate datasets are analyzed, it is often desirable to reduce their dimensionality. Principal component analysis is one technique for doing this. It replaces the
p
original variables by a smaller number,
q
, of derived variables, the principal components, which are linear combinations of the original variables. Often, it is possible to retain most of the variability in the original variables with
q
very much smaller than
p
. Despite its apparent simplicity, principal component analysis has a number of subtleties, and it has many uses and extensions. A number of choices associated with the technique are briefly discussed, namely, covariance or correlation, how many components, and different normalization constraints, as well as confusion with factor analysis. Various uses and extensions are outlined.
Face‐to‐Face Surveys
Authors: Doyle James K.
Published: September 2014

In a face‐to‐face survey, an interviewer is physically present to ask the survey questions and to assist the respondent in answering them. This survey delivery mode can offer many advantages over mail and telephone surveys in terms of the complexity and quality of the data collected. However, because these advantages come with significantly increased logistical costs as well as additional potential sources of response bias, face‐to‐face surveys are typically conducted only when there are compelling reasons to opt out of other survey delivery modes.
Cohort Sequential Design
Authors: Prinzie Peter , Onghena Patrick
Published: September 2014

Cohort‐sequential designs or accelerated longitudinal designs are designs in which adjacent segments consisting of limited longitudinal data on a specific age cohort can be linked together with similar segments from other temporally related age cohorts to determine the existence of a common developmental trend. These designs enable researchers to study individual development over a long interval of the life course by limited repeated measurements of independent age cohorts, resulting in temporally overlapping measurements of the various age groups. Such designs create possibilities not available in standard longitudinal designs for separating age effects from cohort and period effects.
P

Value
Authors: Goodman Steven N.
Published: September 2014

The
P
value is the probability, under a given simple hypothesis, of the observed or a more extreme value of a test statistic. Problems discussed include that of the choice of test statistic, the relevance of alternative hypotheses, ambiguity about the sample space, and the interpretation generally. The distinction between one‐sided and two‐sided tests is a source of confusion. Bayesian considerations are discussed.
National Institutes of Health Stroke Scale (
NIHSS
)
Authors: Ortiz Gustavo A. , L. Sacco Ralph
Published: September 2014

The National Institutes of Health Stroke Scale (NIHSS) is a systematic assessment tool designed to measure the neurological deficits most often seen with acute stroke. It assesses level of consciousness, gaze, visual fields, facial weakness, motor performance of the extremities, sensory deficit, coordination (ataxia), language (aphasia), speech (dysarthria), and hemi‐inattention (neglect). For all parameters, a value of 0 is normal; so, the higher the score, the worse the neurological deficit (the highest possible score is 42). The scale was designed to be done quickly and easily at the bedside to provide a rapid and standardized assessment of neurological function in the early periods after a stroke. It has been validated and has been shown to be reliable, even when performed by non‐neurologists and non‐physicians.
Analysis of VarianceANOVA
Authors: Kaufmann Jörg , Schering AG
Published: September 2014

The development of analysis of variance (ANOVA) methodology has in turn had an influenced on the types of experimental research being carried out in many fields. ANOVA is one of the most commonly used statistical techniques, with applications across the full spectrum of experiments in agriculture, biology, chemistry, toxicology, pharmaceutical research, clinical development, psychology, social science, and engineering. The procedure involves the separation of total observed variation in the data into individual components attributable to various factors as well as those caused by random or chance fluctuation. It allows performing hypotheses tests of significance to determine which factors influence the outcome of the experiment. However, although hypothesis testing is certainly a very useful feature of the ANOVA, it is by no means the only aspect. The methodology was originally developed by Sir Ronald A. Fisher, the pioneer and innovator of the use and applications of statistical methods in experimental design who coined the name “Analysis of Variance – ANOVA.”
Therapeutic Index
Authors: Abughazaleh Raed D. , Tracy Timothy S.
Published: September 2014

Therapeutic index is an expression of the relative toxicity as compared to efficacy of a given compound. In animal studies, it can be computed as the ratio of the median lethal dose (LD50) to the median effective dose (ED50). In humans, it is frequently expressed as the ratio of the median toxic dose (TD50) to the ED50. Several issues limit the utility of the therapeutic index, and to‐date there remains no official list of drugs considered to possess narrow therapeutic indices. Mortality is a poor measure of a drug's toxicity and raises ethical concerns in animal studies. Similarly, ED50can be a poor measure of a drug's effectiveness because of lack of consistency in endpoint biomarkers and because the ED50may be different for multiple conditions the drug may be used to treat. When LD50and ED50are obtained in animals, any extrapolation to humans is limited. In addition, multiple factors of interindividual and intraindividual variability exist in humans and can limit the utility of a therapeutic index estimate. Interindividual variability can be caused by either pharmacokinetic or pharmacodynamic differences, and may play an important role in brand‐to‐generic switching of narrow therapeutic index drugs. Intraindividual variability can also be related to physiologic factors that affect absorption, distribution, metabolism, or excretion of a drug. In conclusion, use of a therapeutic index requires an understanding of its limitations, and may be most useful in the preclinical stages of drug testing where limited experience of the drug's administration is available. To date, there remains no official guidance to research laboratories and pharmaceutical companies on the optimal use of therapeutic index.
Turbulent Diffusion
Authors: Chatwin Philip , Sullivan Paul
Published: September 2014

From the point of view of the environment, arguably the most important practical property of fluids (i.e. liquids and gases) in motion is how they transport heat and matter. Examples of the latter include the spreading of foreign gases (e.g. SO2, NO2 and many others) and particulates in the atmosphere, the dispersion of plankton in the seas and oceans, and the distribution of salt in estuaries. Nearly all fluid motions in the environment are turbulent. This means that the motion is unpredictable, changing apparently at random in both space and time.
Efficient, Large Area, and Thick Junction Polymer Solar Cells with Balanced Mobilities and Low Defect Densities
Authors: Armin Ardalan , Hambsch Mike , Wolfer Pascal , Jin Hui , Li Jun , Shi Zugui , Burn Paul L. , Meredith Paul
Published: September 2014

The high power conversion efficiencies (PCEs) of laboratory‐scale polymer‐based organic solar cells are yet to translate to large area modules because of a number of factors including the relatively large sheet resistance of available transparent conducting electrodes (TCEs), and the high defect densities associated with thin organic semiconductor junctions. The TCE problem limits device architectures to narrow connected strips (<1 cm) causing serious fabrication difficulties and extra costs. Thin junctions are required because of poor charge transport (imbalanced mobilities) in the constituent organic semiconductors. These issues are addressed using a combination of approaches to create thick junctions conformally coated on low sheet resistance metal grid TCEs. An essential feature of these thick junctions is balanced carrier mobilities, which affords high fill factors and efficient carrier extraction. Conformal coating is achieved by promoting enhanced intermolecular interactions in the coating solution using a high molecular weight polymeric semiconductor and appropriate solvent system. This combination of balanced mobilities, conformal coating and metallic grid TCEs is a simple and generic approach to the fabrication of defect‐free large area organic solar cells (OSCs). The approach is demonstrated with 25 cm2 monolithic devices possessing aperture‐corrected power conversion efficiencies of 5% and fill factors exceeding 0.5.
Inception cohort study of workers exposed to toluene diisocyanate at a polyurethane foam factory: Initial one‐year follow‐up
Authors: Gui Wei , Wisnewski Adam V. , Neamtiu Iulia , Gurzau Eugen , Sparer Judith A. , Stowe Meredith H. , Liu Jian , Slade Martin D. , Rusu Olivia A. , Redlich Carrie A.
Published: September 2014

Background

Isocyanates are one of the most commonly reported causes of occupational asthma; however, the risks of developing isocyanate asthma in modern production facilities remain poorly defined. We evaluated TDI exposure and respiratory health among an inception cohort of workers during their first year of employment at a new polyurethane foam production factory.

Methods

Forty‐nine newly hired workers were evaluated pre‐employment, 6‐months, and 12‐months post‐employment through questionnaire, spirometry, and TDI‐specific serology. Airborne TDI levels were monitored by fixed‐point air sampling and limited personal sampling. Qualitative surface SWYPE™ tests were performed to evaluate potential sources of skin exposure.

Results

Airborne TDI levels overall were low; over 90% of fixed‐point air measurements were below the limit of detection (0.1 ppb). Over the first year of employment, 12 of the 49 original workers (24.5%) were lost to follow‐up, no additional workers were enrolled, and seven of the 49 original workers (14.2%) developed either new asthma symptoms (N = 3), TDI‐specific IgG (N = 1), new airflow obstruction (N = 1) and/or a decline in FEV1 ≥ 15% (N = 3), findings that could indicate TDI‐related health effects. The prevalence of current asthma symptoms was significantly higher in the workers lost to follow‐up compared to those who completed the 12‐month follow‐up (25% vs. 2.7%; P = 0.04).

Conclusions

The findings suggest possible early TDI‐related health effects in a modern polyurethane production plant. These findings also highlight the need for further longitudinal evaluation of these workers and the challenges of studying workers at risk for isocyanate asthma. Am. J. Ind. Med. 57:1207–1215, 2014. © 2014 Wiley Periodicals, Inc.
Highly Ordered and Highly Aligned Two‐Dimensional Binary Superlattice of a SWNT/Cylindrical‐Micellar System
Authors: Lim Sung‐Hwan , Jang Hyung‐Sik , Ha Jae‐Min , Kim Tae‐Hwan , Kwasniewski Pawel , Narayanan Theyencheri , Jin Kyeong Sik , Choi Sung‐Min
Published: September 2014

We report a highly ordered intercalated hexagonal binary superlattice of hydrophilically functionalized single‐walled carbon nanotubes (p‐SWNTs) and surfactant (C12E5) cylindrical micelles. When p‐SWNTs (with a diameter slightly larger than that of the C12E5 cylinders) were added to the hexagonally packed C12E5 cylindrical‐micellar system, p‐SWNTs positioned themselves in such a way that the free‐volume entropies for both p‐SWNTs and C12E5 cylinders were maximized, thus resulting in the intercalated hexagonal binary superlattice. In this binary superlattice, a hexagonal array of p‐SWNTs is embedded in a honeycomb lattice of C12E5 cylinders. The intercalated hexagonal binary superlattice can be highly aligned in one direction by an oscillatory shear field and remains aligned after the shear is removed.
Jojoba oil biorefinery using a green catalyst. Part II: Feasibility study and economical assessment
Authors: Sánchez Marcos , Marchetti Jorge M. , El Boulifi Noureddin , Martínez Mercedes , Aracil José
Published: September 2014

In this work, the study of market and economic variables for a jojoba oil biorefinery is conducted. The raw materials used in this process were jojoba oil, methanol, a green catalyst derived from the fish industry, hexane, and diethylether. The products obtained in this process are jojobyl alcohols, which have pharmaceutical applications, and the fatty acid metyl esters (FAME) which are used to generate energy in the plant. The economic sensitivity analysis was performed for the internal rate of return (IRR) and payback time when the prices of jojobyl alcohols, jojoba oil, management and treatment of the diethylether:hexane stream, and methanol vary in fixed ranges. In addition, the influences of the product failure, tax percentage, advertisement and selling expenses, and the royalties over the economy of the process were also studied. The variables which have the most impact on the economy of the process were the jojobyl alcohol and jojoba oil price; small modifications in these variables result in relevant changes in the economy of the biorefinery. However, the price of the methanol is not significant for the profitability of the plant because 85% of the excess alcohol used in the transesterification step is recycled. © 2014 Society of Chemical Industry and John Wiley & Sons, Ltd
Effect of weak static magnetic fields on the development of cultured skeletal muscle cells
Authors: Surma Sergei V. , Belostotskaya Galina B. , Shchegolev Boris F. , Stefanov Vasily E.
Published: September 2014

We studied the effect produced on the development and functional activity of skeletal muscle cells from newborn Wistar rats in primary culture by weak static magnetic fields (WSMF; 60–400 µT) with a high capacity of penetrating the biological media. To reduce the impact of external magnetic fields, cells were cultured at 37 °C in a multilayered shielding chamber with the attenuation coefficient equal to 160. WSMF inside the chamber was created by a circular permanent magnet. We found that the application of WSMF with the magnetic field strength only a few times that of the geomagnetic field can accelerate the development of skeletal muscle cells, resulting in the formation of multinuclear hypertrophied myotubes. WSMF was shown to induce 1.5‐ to 3.5‐fold rise in the concentration of intracellular calcium [Ca2+]idue to the release of Ca2+from the sarcoplasmic reticulum (SR) through ryanodine receptors (RyR), which increases in the maturation of myotubes. We also found that fully differentiated myotubes at late stages of development were less sensitive to WSMF, manifesting a gradual decrease in the frequency of contractions. However, myotubes at the stage when electromechanical coupling was forming dramatically reduced the frequency of contractions during the first minutes of their exposure to WSMF. Bioelectromagnetics 35:537–546, 2014. © 2014 Wiley Periodicals, Inc.
Dosimetric study of fetal exposure to uniform magnetic fields at 50 Hz
Authors: Liorni Ilaria , Parazzini Marta , Fiocchi Serena , Douglas Mark , Capstick Myles , Gosselin Marie‐Christine , Kuster Niels , Ravazzani Paolo
Published: September 2014

In this paper, fetal exposure to uniform magnetic fields (MF) with different polarizations is quantified at 50 Hz. Numerical computations were performed on high‐resolution pregnant models at 3, 7, and 9 months of gestational age (GA), that distinguish a high number of fetal tissues. Fetal whole‐body and tissue‐specific induced electric fields (E) and current densities (J) were analyzed as a function of both the extremely low frequency magnetic field (ELF‐MF) polarization and GA. Additionally, the induced field variation due to changes in fetal position was analyzed by means of two new pregnant models. The uncertainty budget due to the grid resolution was also calculated. Finally, the compliance of the fetal exposure to the ICNIRP Guidelines was checked. A fetal exposure matrix was built at 50 Hz, which could be used to further investigate possible interaction mechanisms between ELF‐MF and the associated health risk. Some specific findings were: (1) the induced fields increased with GA; (2) the maxima E were found in skin and fat tissues at each GA; (3) fetal tissue‐specific exposure was modified as a function of GA and polarization; (4) the change of the fetal position in the womb significantly modified the induced E in some fetal tissues; (5) the induced fields were in compliance with ICNIRP Guidelines and the results were quite below the permitted threshold limit. Bioelectromagnetics 35:580–597, 2014. © 2014 Wiley Periodicals, Inc.
Glycoarrays with engineered phages displaying structurally diverse oligosaccharides enable high‐throughput detection of glycan–protein interactions
Authors: Çelik Eda , Ollis Anne A. , Lasanajak Yi , Fisher Adam C. , Gür Göksu , Smith David F. , DeLisa Matthew P.
Published: September 2014

Glycan microarrays have become a powerful platform to investigate the interactions of carbohydrates with a variety of biomolecules. However, the number and diversity of glycans available for use in such arrays represent a key bottleneck in glycan array fabrication. To address this challenge, we describe a novel glycan array platform based on surface patterning of engineered glycophages that display unique carbohydrate epitopes. Specifically, we show that glycophages are compatible with surface immobilization procedures and that phage‐displayed oligosaccharides retain the ability to be recognized by different glycan‐binding proteins (e.g. antibodies and lectins) after immobilization. A key advantage of glycophage arrays is that large quantities of glycophages can be produced biosynthetically from recombinant bacteria and isolated directly from bacterial supernatants without laborious purification steps. Taken together, the glycophage array technology described here should help to expand the diversity of glycan libraries and provide a complement to the existing toolkit for high‐throughput analysis of glycan–protein interactions.
Binding of polyunsaturated fatty acids to LXRα and modulation of SREBP‐1 interaction with a specific SCD1 promoter element
Authors: Caputo Mariella , De Rosa Maria Caterina , Rescigno Tania , Zirpoli Hylde , Vassallo Antonio , De Tommasi Nunziatina , Torino Gaetano , Tecce Mario Felice
Published: September 2014

Stearoyl‐CoA desaturase 1 (SCD1) is the rate limiting enzyme in unsaturated fatty acid biosynthesis. This enzyme has an important role in the regulation of hepatic lipogenesis and lipid oxidation, and alterations in these pathways may lead to several diseases. We examined, in HepG2 cell cultures, the mechanism of SCD1 regulation considering the involvement of two transcription factors: liver X receptor alpha (LXRα) and sterol regulatory element‐binding protein‐1 (SREBP‐1), also investigating the effect of dietary polyunsaturated fatty acids (PUFAs) on this process. The analysis of SCD1 promoter allowed to identify a functional SREBP‐1 binding site (SRE 1). LXRα activation increased SCD1 protein level through upregulation of SREBP‐1 and its consequent binding to SRE 1 sequence. Polyunsaturated docosahexaenoic acid (DHA, C22:6), eicosapentaenoic acid (EPA, C20:5) and arachidonic acid (AA, C20:4) were able to reduce SREBP‐1 binding to SCD1 promoter, while saturated stearic acid (SA, C18:0) did not give any effect. Surface plasmon resonance analysis showed a direct binding of DHA, EPA and AA to LXRα. These data indicate a direct inhibitory interaction of PUFAs with LXRα, a consequent reduction of SREBP‐1 and of its binding to SCD1 promoter. This information provides a mechanism to explain the regulation of lipogenic pathways induced by PUFAs. Copyright © 2014 John Wiley & Sons, Ltd.
Model Calculations on Heterogeneous Elastic Bodies under All‐Round Compression
Authors: Raasch Jürgen
Published: September 2014

Hydraulische Zerkleinerung eignet sich besonders, wenn sich Komponenten in ihren elastischen Eigenschaften deutlich unterschieden. Hier wurden für zwei Modellkörper die Grundgleichungen der linearen Elastizitätstheorie formuliert. Sowohl in Zylinder‐ als auch in kartesischen Koordinaten lässt sich die Lösung des Gleichungssystems durch die Einführung einer Spannungsfunktion auf die Lösung der Bipotenzialgleichung zurückführen. Dabei müssen die jeweiligen Randbedingungen erfüllt werden. Im Fall der allseitigen gleichmäßigen Druckbeanspruchung gelingt dies für beide Modellkörper mit Lösungsansätzen in Integralform.
Asymmetric Hydrogenation of 2‐Aryl‐5,6‐dihydropyrazine Derivatives with Chiral Cationic Ruthenium Diamine Catalysts
Authors: Li Yong , He Yanmei , Chen Fei , Fan Qinghua
Published: September 2014

The first asymmetric hydrogenation of unfunctionalized 2‐substituted and 2,3‐disubstituted 5,6‐dihydropyrazines catalyzed by chiral cationic Ru‐diamine complex (R,R)‐1a was developed, affording chiral piperazine derivatives with good enantioselectivities (up to 89% ee).
Quantitative Derivation of the Gross‐Pitaevskii Equation
Authors: Benedikter Niels , de Oliveira Gustavo , Schlein Benjamin
Published: September 2014

Starting from first‐principle many‐body quantum dynamics, we show that the dynamics of Bose‐Einstein condensates can be approximated by the time‐dependent nonlinear Gross‐Pitaevskii equation, giving a bound on the rate of the convergence. Initial data are constructed on the bosonic Fock space applying an appropriate Bogoliubov transformation on a coherent state with expected number of particles N. The Bogoliubov transformation plays a crucial role; it produces the correct microscopic correlations among the particles. Our analysis shows that, on the level of the one‐particle reduced density, the form of the initial data is preserved by the many‐body evolution, up to a small error that vanishes as N−1/2 in the limit of large N.© 2015 Wiley Periodicals, Inc.
“Unintended effects”: A theorem for complex systems
Authors: Usó‐Doménech J.L. , Nescolarde‐Selva J. , Lloret‐Climent M.
Published: September 2014

Unintended effects are well known to economists and sociologists and their consequences may be devastating. The main objective of this article is to formulate a mathematical theorem, based on Gödel's famous incompleteness theorem, in which it is shown, that from the moment deontical modalities (prohibition, obligation, permission, and faculty) are introduced into the social system, responses are allowed by the system that are not produced, however, prohibited responses or unintended effects may occur. © 2014 Wiley Periodicals, Inc. Complexity 21: 342–354, 2015
Quantifying the effects of vegetation structure on snow accumulation and ablation in mixed‐conifer forests
Authors: Broxton P. D. , Harpold A. A. , Biederman J. A. , Troch P. A. , Molotch N. P. , Brooks P. D.
Published: September 2014

Snowmelt from forested, mountainous environments in the western United States is a critical regional water resource for streamflow and ecological productivity. These landscapes are undergoing rapid changes from the combined effects of forest fires, insect infestation and climate change. Numerous observational studies demonstrate that trees control snowpack accumulation and ablation over scales of tens of metres. Representing forest heterogeneity in models is important for understanding how changes in climate and vegetation cover affect the snowpack; yet, many snow models simplify a forest into two categories: canopy covered and non‐canopy covered. We combine existing parameterizations of mass and energy fluxes within a new three‐dimensional framework informed by Airborne Laser Swath Mapping (ALSM)‐derived canopy maps and evaluated with ALSM‐derived snow depth maps to explicitly simulate snow cover in relation to heterogeneous canopy. Model results capture much of the observed snow variability depicted in the 1‐m ALSM‐derived snow depth maps. Observations and modelled results identify open areas <15 m from tree canopies as having more snow and more snow variability than areas >15 m from tree canopies, and modelled results predict that open areas <15 m from tree canopies have 30–40% more net snow water input than areas that are underneath tree canopies and 10–25% more net snow water input than areas that are >15 m from tree canopies. Furthermore, 1‐m simulations give higher estimates for net snow water input than coarser resolution simulations, mainly in areas with fewer trees. These results suggest the importance of explicitly representing canopy edges in snow models. Copyright © 2014 John Wiley & Sons, Ltd.
Copper‐Catalyzed Formation of C–O Bonds by Oxidative Coupling of Benzylic Alcohols with Ethers
Authors: Wang Quan , Geng Haoran , Chai Wen , Zeng Xiaojun , Xu Min , Zhu Cheng , Fu Renzhong , Yuan Rongxin
Published: September 2014

The copper‐catalyzed formation of C–O bonds by oxidative coupling of benzylic alcohols with ethers was realized in open air. A series of α‐acyloxy ethers were obtained in good yields with aqueous tert‐butyl hydroperoxide as the oxidant.
Eye movements during visual search for emotional faces in individuals with chronic headache
Authors: Schoth D.E. , Godwin H.J. , Liversedge S.P. , Liossi C.
Published: September 2014

Background

Attentional biases for pain‐related information have been frequently reported in individuals with chronic pain. Recording of participants' eye movements provides a continuous measure of attention, although to date this methodology has received little use in research exploring attentional biases in chronic pain. The aim of the current investigation was to explore the specificity of attentional orienting bias using a novel visual search task while recording participant eye movement behaviours. This also allowed for the investigation of whether attentional biases for pain‐related information exist in the presence of multiple stimuli competing for attention.

Methods

Twenty‐three participants with chronic headache and 24 pain‐free, healthy control participants were engaged in a visual search task where pain, angry, happy and neutral faces were used as both target and distractor stimuli. While completing this task, participants' eye movements were recorded.

Results

Supporting the adopted hypothesis, participants with chronic headache, relative to healthy controls, demonstrated a significantly higher proportion of initial fixations to target pain expressions when the pain expressions were presented in displays containing neutral‐distractor faces. No significant differences were found between groups in the time taken to fixate target pain expressions (localization time).

Conclusions

Individuals with chronic headache show facilitated initial orienting towards pain expressions specifically when used as targets in a visual search task. This study adds to a growing body of research supporting the presence of pain‐related attentional biases in chronic pain as assessed via different experimental paradigms, and shows biases to exist when multiple stimuli competing for attention are presented simultaneously.
Microfluidic platform with four orthogonal and overlapping gradients for soluble compound screening in regenerative medicine research
Authors: Harink Björn , Le Gac Séverine , Barata David , van Blitterswijk Clemens , Habibovic Pamela
Published: September 2014

We present here a screening method based on a microfluidic platform, which can generate four orthogonal and overlapping concentration gradients of soluble compounds over a monolayer of cells, in combination with automated and in situ image analysis, for use in regenerative medicine research. The device includes a square chamber in which cells are grown, and four independent supply channels along the sides of the chamber, which are connected through an array of small diffusion channels. Compounds flown through the supply channels diffuse through diffusion channels into the chamber to create a gradient over the cell culture area. Further, the chamber is connected to two channels intended for introduction of cells and in situ staining. In this study, the dimensions of the different channels were optimized through finite element modeling to yield stable gradients, and two designs were used with gradients spanning 2.9–2.4 μM and 3.4–2.0 μM. Next, overlapping gradients were generated using four rhodamine‐derived fluorescent dyes, and imaged using confocal microscopy. Finally, the platform was applied to assess the concentration‐dependent response of an osteoblastic cell line exposed to a hypoxia‐mimicking molecule phenanthroline, using an in situ fluorescent staining assay in combination with image analysis, applicable to closed microfluidic devices. The on‐chip assay yielded results comparable to those observed in conventional culture, where a range of concentrations was tested in independent microwells. In the future, we intend to use this method to complement or replace current research approaches in screening soluble compounds for regenerative medicine, which are often based on one‐sample‐for‐one‐experiment principle.
A toxicokinetic study of specifically acting and reactive organic chemicals for the prediction of internal effect concentrations in Scenedesmus vacuolatus
Authors: Vogs Carolina , Kühnert Agnes , Hug Christine , Küster Eberhard , Altenburger Rolf
Published: September 2014

The toxic potency of chemicals is determined by using the internal effect concentration by accounting for differences in toxicokinetic processes and mechanisms of toxic action. The present study examines toxicokinetics of specifically acting and reactive chemicals in the green algae Scenedesmus vacuolatus by using an indirect method. Concentration depletion in the exposure medium was measured for chemicals of lower (log KOW < 3: isoproturon, metazachlor, paraquat) and moderate (log KOW 4-5: irgarol, triclosan, N-phenyl-2-naphthylamine) hydrophobicity at 7 to 8 time points over 240 min or 360 min. Uptake and overall elimination rates were estimated by fitting a toxicokinetic model to the observed concentration depletions. The equilibrium of exposure concentrations was reached within minutes to hours or was even not observed within the exposure time. The kinetics of bioconcentration cannot be explained by the chemical's hydrophobicity only, but influential factors such as ionization of chemicals, the ion trapping mechanism, or the potential susceptibility for biotransformation are discussed. Internal effect concentrations associated with 50% inhibition of S. vacuolatus reproduction were predicted by linking the bioconcentration kinetics to the effect concentrations and ranged from 0.0480 mmol/kg wet weight to 7.61 mmol/kg wet weight for specifically acting and reactive chemicals. Knowing the time-course of the internal effect concentration may promote an understanding of toxicity processes such as delayed toxicity, carry-over toxicity, or mixture toxicity in future studies. Environ Toxicol Chem 2015;34:100–111. © 2014 SETAC
Meta‐analysis of flow modeling performances—to build a matching system between catchment complexity and model types
Authors: Zhuo Lu , Dai Qiang , Han Dawei
Published: September 2014

Hydrological models play a significant role in modelling river flow for decision making support in water resource management. In the past decades, many researchers have made a great deal of efforts in calibrating and validating various models, with each study being focused on one or two models. As a result, there is a lack of comparative analysis on the performance of those models to guide hydrologists to choose appropriate models for the individual climate and physical conditions. This paper describes a two‐level meta‐analysis to develop a matching system between catchment complexity (based on catchment significant features (CSFs)) and model types. The intention is to use the available CSF information for choosing the most suitable model type for a given catchment. In this study, the CSFs include the elements of climate, soil type, land cover and catchment scale. Specific choices of model types in small and medium catchments are further explored with all CSF information obtained. In particular, it is interesting to find that semi‐distributed models are the most suitable model type for catchments with the area over 3000 km2, regardless of other CSFs. The potential methodology for expanding the matching system between catchment complexity and model complexity is discussed. Copyright © 2014 John Wiley & Sons, Ltd.
Investigation of Unique Protonic and Hydrodynamic Behavior of Aqueous Solutions Confined in Extended Nanospaces
Authors: Morikawa Kyojiro , Tsukahara Takehiko
Published: September 2014

Studies on novel devices utilizing characteristics of confined geometries have attracted much attention. In particular, a 10–1,000 nm space (extended nanospace) has been expected to establish superior chemical analysis systems in liquid phases, because it not only bridges the methodological gap between conventional nanotechnology and microfluidic technology, but also the scientific one between single molecules and the bulk condensed phase. Therefore, engineering, fluidics, and chemistry concerned with extended nanospaces have been investigated, and unique physicochemical phenomena in the spaces have been clarified. In this review, we summarize recent research outcomes about protonic and hydrodynamic properties of liquids confined in extended nanospaces. Furthermore, we assume a novel molecular description, composed of the electric double layer (EDL) model and the three‐phase model, consisting of adsorbed, proton transfer, and bulk phases, to explain the unique properties induced by the extended nanospace confinement. Finally, the device applications using extended nanospaces are introduced and their potentials are discussed.
IL-4/CCL22/CCR4 Axis Controls Regulatory T-Cell Migration That Suppresses Inflammatory Bone Loss in Murine Experimental Periodontitis
Authors: Araujo-Pires Ana Claudia , Vieira Andreia Espindola , Francisconi Carolina Favaro , Biguetti Claudia Cristina , Glowacki Andrew , Yoshizawa Sayuri , Campanelli Ana Paula , Trombone Ana Paula Favaro , Sfeir Charles S , Little Steven R , Garlet Gustavo Pompermaier
Published: September 2014

Inflammatory bone resorption is a hallmark of periodontitis, and Tregs and Th2 cells are independently associated with disease progression attenuation. In this study, we employed an infection-triggered inflammatory osteolysis model to investigate the mechanisms underlying Treg and Th2 cell migration and the impact on disease outcome. Aggregatibacter actinomycetemcomitans–infected C57Bl/6 (wild-type [WT]) mice develop an intense inflammatory reaction and alveolar bone resorption, and Treg and Th2 cell migration is temporally associated with disease progression attenuation. Tregs extracted from the lesions preferentially express CCR4 and CCR8, whereas Th2 cells express CCR3, CCR4, and CCR8. The absence of CCR5 and CCR8 did not significantly impact the migration of Tregs and Th2 cells or affect the disease outcome. CCR4KO mice presented a minor reduction in Th2 cells in parallel with major impairment of Treg migration, which was associated with increased inflammatory bone loss and higher proinflammatory and osteoclastogenic cytokine levels. The blockade of the CCR4 ligand CCL22 in WT mice resulted in an increased inflammatory bone loss phenotype similar to that in the CCR4KO strain. Adoptive transfer of CCR4+ Tregs to the CCR4KO strain revert the increased disease phenotype to WT mice–like levels; also, the in situ production of CCL22 in the lesions is mandatory for Tregs migration and the consequent bone loss arrest. The local release of exogenous CCL22 provided by poly(lactic-co-glycolic acid) (PLGA) microparticles promotes migration of Tregs and disease arrest in the absence of endogenous CCL22 in the IL-4KO strain, characterized by the lack of endogenous CCL22 production, defective migration of Tregs, and exacerbated bone loss. In summary, our results show that the IL-4/CCL22/CCR4 axis is involved in the migration of Tregs to osteolytic lesion sites, and attenuates development of lesions by inhibiting inflammatory migration and the production of proinflammatory and osteoclastogenic mediators. © 2014 American Society for Bone and Mineral Research
Does preoperative biliary drainage compromise the long‐term survival of patients with pancreatic head carcinoma?
Authors: Murakami Yoshiaki , Uemura Kenichiro , Hashimoto Yasushi , Kondo Naru , Nakagawa Naoya , Sasaki Hayato , Hatano Naoto , Kohmo Toshiaki , Sueda Taijiro
Published: September 2014

Background and Objectives

The aim of this study was to determine the impact of preoperative biliary drainage (PBD) on long‐term survival in patients with pancreatic head carcinoma after surgical resection.

Methods

Medical records of 160 patients with pancreatic head carcinoma who underwent surgical resection were reviewed retrospectively. Clinicopathological parameters including long‐term survival were compared between patients who did and did not undergo PBD.

Results

Overall survival of patients who underwent PBD (n = 93) was significantly worse than that of patients who did not (n = 67) by univariate analysis (P = 0.030). However, multivariate analysis revealed that PBD was not an independent prognostic factor for overall survival (P = 0.227). Patients who underwent percutaneous transhepatic biliary drainage (PTBD) had significantly worse survival than patients who underwent endoscopic retrograde biliary drainage (ERBD, P = 0.038) and patients who did not undergo PBD (P = 0.001). The rate of peritoneal recurrence in patients who underwent PTBD was significantly higher than that of patients who underwent ERBD (P = 0.033) or patients who did not undergo PBD (P = 0.034).

Conclusions

PBD may not affect the long‐term survival of patients with pancreatic head carcinoma if ERBD is used. J. Surg. Oncol. 2015 111:270–276. © 2014 Wiley Periodicals, Inc.
Synthesis, Properties, and Applications of Ion‐Containing Polyurethane Segmented Copolymers
Authors: Nelson Ashley M. , Long Timothy E.
Published: September 2014

Despite the well‐established foundation of polyurethane chemistry in both industry and academia, research continues at a vigorous pace to refine synthetic processes and discover new functional materials. Incorporating ionic groups into polymers is a synthetic parameter capable of tailoring polymer properties and enabling emerging technologies. This review focuses on recent effort in the field of ion‐containing segmented polyurethane copolymers. Multiple synthetic strategies to incorporate both cationic and anionic sites, including a particular focus on waterborne polyurethane dispersions and green synthetic methods, are examined. Fundamental structure–property relationships based on ionic structure, content, and placement are explored and many applications, including biomedical products and polymer electrolytes for energy devices are discussed.

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