bluuebunny/crossref_metadata_2025_split huggingface dataset:
Summary Measure Analysis of Longitudinal Data
Authors: Everitt Brian S. 
Published: September 2014

Abstract

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

Abstract

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

Abstract
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

Abstract
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

Abstract

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

Abstract
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

AbstractThe 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

AbstractTherapeutic 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

AbstractFrom 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.
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

BackgroundIsocyanates 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.MethodsForty‐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.ResultsAirborne 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).ConclusionsThe 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

AbstractWe 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

AbstractIn 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
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

AbstractGlycan 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.
Model Calculations on Heterogeneous Elastic Bodies under All‐Round Compression
Authors: Raasch Jürgen 
Published: September 2014

AbstractHydraulische 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

AbstractThe 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).
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

AbstractSnowmelt 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

AbstractThe 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

AbstractBackgroundAttentional 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.MethodsTwenty‐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.ResultsSupporting 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).ConclusionsIndividuals 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

Abstract

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 &lt; 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