bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical estimation of redox potential of biological quinone cofactors
Authors: Gillet Natacha , Lévy Bernard , Moliner Vicent , Demachy Isabelle , de la Lande Aurélien
Published: May 2017

Redox potentials are essential to understand biological cofactor reactivity and to predict their behavior in biological media. Experimental determination of redox potential in biological system is often difficult due to complexity of biological media but computational approaches can be used to estimate them. Nevertheless, the quality of the computational methodology remains a key issue to validate the results. Instead of looking to the best absolute results, we present here the calibration of theoretical redox potential for quinone derivatives in water coupling QM + MM or QM/MM scheme. Our approach allows using low computational cost theoretical level, ideal for long simulations in biological systems, and determination of the uncertainties linked to the calculations. © 2017 Wiley Periodicals, Inc.
Combined quantum‐mechanical molecular mechanics calculations with NWChem and AMBER: Excited state properties of green fluorescent protein chromophore analogue in aqueous solution
Authors: Pirojsirikul Teerapong , Götz Andreas W. , Weare John , Walker Ross C. , Kowalski Karol , Valiev Marat
Published: May 2017

Combined quantum mechanical molecular mechanics (QM/MM) calculations have become a popular methodology for efficient and accurate description of large molecular systems. In this work we introduce our development of a QM/MM framework based on two well‐known codes—NWChem and AMBER. As an initial application area we are focused on excited state properties of small molecules in an aqueous phase using an analogue of the green fluorescent protein (GFP) chromophore as a particular test case. Our approach incorporates high level coupled cluster theory for the analysis of excited states providing a reliable theoretical analysis of effects of an aqueous solvation environment on the photochemical properties of the GFP chromophore. Using a systematic approach, which involves comparison of gas phase and aqueous phase results for different protonation states and conformations, we resolve existing uncertainties regarding the theoretical interpretation of experimental data. We observe that the impact of aqueous environment on charged states generally results in blue shifts of the absorption spectra, but the magnitude of the effect is sensitive to both protonation state and conformation and can be rationalized based on charge movement into the area of higher/lower external electrostatic potentials. At neutral pH levels the experimentally observed absorption signal is most likely coming from the phenol protonated form. Our results also show that the high level electron correlated method is essential for a proper description of excited states of GFP. © 2017 Wiley Periodicals, Inc.
Functional analysis of the musculo‐skeletal system of the gill apparatus in Heptranchias perlo (Chondrichthyes: Hexanchidae)
Authors: Kryukova Nadezhda V.
Published: May 2017

Musculo‐skeletal morphology is an indispensable source for understanding functional adaptations. Analysis of morphology of the branchial apparatus of Hexanchiform sharks can provide insight into aspects of their respiration that are difficult to observe directly. In this study, I compare the structure of the musculo‐skeletal system of the gill apparatus of Heptranchias perlo and Squalus acanthias in respect to their adaptation for one of two respiratory mechanisms known in sharks, namely, the active two‐pump (oropharyngeal and parabranchial) ventilation and the ram‐jet ventilation. In both species, the oropharyngeal pump possesses two sets of muscles, one for compression and the other for expansion. The parabranchial pump only has constrictors. Expansion of this pump occurs only due to passive elastic recoil of the extrabranchial cartilages. In Squalus acanthias the parabranchial chambers are large and equipped by powerful superficial constrictors. These muscles and the outer walls of the parabranchial chambers are much reduced in Heptranchias perlo, and thus it likely cannot use this pump. However, this reduction allows for vertical elongation of outer gill slits which, along with greater number of gill pouches, likely decreases branchial resistance and, at the same time, increases the gill surface area, and can be regarded as an adaptation for ram ventilation at lower speeds.
Ontogenetic shifts of heart position in snakes
Authors: Lillywhite Harvey B. , Lillywhite Steven M.
Published: May 2017

Heart position relative to total body length (TL) varies among snakes, with anterior hearts in arboreal species and more centrally located hearts in aquatic or ground‐dwelling species. Anterior hearts decrease the cardiac work associated with cranial blood flow and minimize drops in cranial pressure and flow during head‐up climbing. Here, we investigate whether heart position shifts intraspecifically during ontogenetic increases in TL. Insular Florida cottonmouth snakes, Agkistrodon conanti, are entirely ground‐dwelling and have a mean heart position that is 33.32% TL from the head. In contrast, arboreal rat snakes, Pantherophis obsoleta, of similar lengths have a mean heart position that is 17.35% TL from the head. In both species, relative heart position shifts craniad during ontogeny, with negative slopes = −.035 and −.021% TL/cm TL in Agkistrodon and Pantherophis, respectively. Using a large morphometric data set available for Agkistrodon (N = 192 individuals, 23–140 cm TL), we demonstrate there is an anterior ontogenetic shift of the heart position within the trunk (= 4.56% trunk length from base of head to cloacal vent), independent of head and tail allometry which are both negative. However, in longer snakes > 100 cm, the heart position reverses and shifts caudally in longer Agkistrodon but continues toward the head in longer individuals of Pantherophis. Examination of data sets for two independent lineages of fully marine snakes (Acrochordus granulatus and Hydrophis platurus), which do not naturally experience postural gravity stress, demonstrate both ontogenetic patterns for heart position that are seen in the terrestrial snakes. The anterior migration of the heart is greater in the terrestrial species, even if TL is standardized to that of the longer P. obsoleta, and compensates for about 5 mmHg gravitational pressure head if they are fully upright.
Nickel(II)‐assisted enantiomeric differentiation and quantitation of tadalafil by direct electrospray ionization mass spectrometry
Authors: Wang L. , Wang Y. , Chai Y. , Kang Y. , Sun C. , Zeng S.
Published: May 2017

A facile method based on electrospray mass spectrometry was established and validated for the differentiation of enantiomeric tadalafil isomers without using chiral chromatographic separation. The enantiomers were coupled with a chiral selector to form diastereomeric complex ions. Nickel–tadalafil complexes, [NiII(tadalafil)(l‐Trp)‐H]+, produced a characteristic fragment ion at m/z 524 by loss of 1‐methyl‐1,6‐dihydropyrazine‐2,5‐dione via collision‐induced dissociation. The relative abundance of this fragment ion to the precursor contributed to differentiate tadalafil enantiomers, and energy‐resolved product‐ion spectra were applied to determine the molar composition of tadalafil in the mixture (R,R and S,S) as well. In addition, the other two forms of stereomeric isomers of tadalafil (R,S and S,R) could be also distinguished and analyzed by this method. The method was validated in different types of mass spectrometers (AB quadrupole time‐of‐flight and Bruker ion trap) and also verified by a chiral high‐performance liquid chromatography coupled with quadrupole time‐of‐flight. The chiral determination of tadalafil using MS method proved to be rapid (1‐min run time for each sample) and to have the same accuracy and precision comparable to chiral liquid chromatography mass spectrometry methods. This method provides an alternative to commonly used chromatographic technique for chiral determination and is particularly useful in rapid screening in enantioselective synthesis and enantiomeric impurity detection in pharmaceutical industry. Copyright © 2017 John Wiley & Sons, Ltd.
Constrained multi‐objective antenna design optimization using surrogates
Authors: Singh Prashant , Rossi Marco , Couckuyt Ivo , Deschrijver Dirk , Rogier Hendrik , Dhaene Tom
Published: May 2017

A novel surrogate‐based constrained multi‐objective optimization algorithm for simulation‐driven optimization is proposed. The evolutionary algorithms usually applied in antenna design optimization typically require a large number of objective function evaluations to converge. The efficient constrained multiobjective optimization algorithm described in this paper identifies Pareto‐optimal solutions satisfying the required constraints using very few function evaluations. This leads to substantial savings in time and drastically reduces the time to market for expensive antenna design optimization problems. The efficiency of the approach is demonstrated on the design of an L1‐band GPS antenna. The algorithm automatically optimizes the antenna geometry, parametrized by 5 design variables with performance constraints on three objectives. The results are compared with well‐established multiobjective optimization evolutionary algorithms.
On semi‐empirical decomposition of multidecadal climate variability into forced and internally generated components
Authors: Kravtsov Sergey , Callicutt David
Published: May 2017

This paper combines CMIP5 historical simulations and observations of surface temperature to investigate relative contributions of forced and internal climate variability to long‐term climate trends. A suite of estimated forced signals based on surrogate multi‐model ensembles mimicking the statistical characteristics of individual models is used to show that, in contrast to earlier claims, scaled versions of the multi‐model ensemble mean cannot adequately characterize the full spectrum of CMIP5 forced responses, due to misrepresenting the model uncertainty. The same suite of multiple forced signals is also used to derive unbiased estimates of the model simulated internal variability in historical simulations and, after appropriate scaling to match the observed climate sensitivity, to estimate the internal component of climate variability in the observed temperatures. On average, climate models simulate the non‐uniform warming of Northern Hemisphere mean surface temperature well, but are overly sensitive to forcing in the North Atlantic and North Pacific, where the simulations have to be scaled back to match observed trends. In contrast, the simulated internal variability is much weaker than observed. There is no evidence of coupling between the model simulated forced signals and internal variability, suggesting that their underlying dominant physical mechanisms are different. Analysis of regional contributions to the recent global warming hiatus points to the presence of a hemispheric mode of internal climate variability, rather than to internal processes local to the Pacific Ocean. Large discrepancies between present estimates of the simulated and observed multidecadal internal climate variability suggest that our ability to attribute and predict climate change using current generation of climate models is limited.
Development and screening of epoxy‐spacer‐phage cryogels for affinity chromatography: Enhancing the binding capacity
Authors: Noppe Wim , Deckmyn Hans
Published: May 2017

Macroporous epoxy cryogels can be used as an alternative for classical matrices in affinity chromatography. Due to the structural properties of cryogels, with pores of up to 100 μm, crude samples can be processed at high speed without previous manipulations such as clarification or centrifugation. Also, we previously used a peptide‐expressing M13 bacteriophage as an affinity ligand. These ligands show high specificity toward the target to be purified. Combination of both, leads to a relative cost‐effective one‐step chromatographic set‐up delivering a high purity sample (>95%), however, so far with limited capacity. To increase the binding capacity of the affinity columns, we now inserted spacers between the chromatographic matrix and the phage ligand. Both linear spacers, di‐amino‐alkanes (C2–C10), and branched polyethyleneimine spacers with different molecular weights (800 Da–10 kDa) were analyzed. Two types of peptide expressing phage ligands, a linear 15‐mer and a cyclic 6‐mer, were used for screening. Up to a tenfold increase in binding capacity was observed depending on the combination of phage ligand and spacer type.
Quantification of anhydride groups in anhydride‐based epoxy hardeners by reaction headspace gas chromatography
Authors: Xie Wei‐Qi , Gong Yi‐Xian , Yu Kong‐Xian
Published: May 2017

We demonstrate a reaction headspace gas chromatographic method for quantifying anhydride groups in anhydride‐based epoxy hardeners. In this method, the conversion process of anhydride groups can be realized by two steps. In the first step, anhydride groups in anhydride‐based epoxy hardeners completely reacted with water to form carboxyl groups. In the second step, the carboxyl groups reacted with sodium bicarbonate solution in a closed sample vial. After the complete reaction between the carboxyl groups and sodium bicarbonate, the CO2 formed from this reaction was then measured by headspace gas chromatography. The data showed that the reaction in the closed headspace vial can be completed in 15 min at 55°C, the relative standard deviation of the reaction headspace gas chromatography method in the precision test was less than 3.94%, the relative differences between the new method and a reference method were no more than 9.38%. The present reaction method is automated, efficient and can be a reliable tool for quantifying the anhydride groups in anhydride‐based epoxy hardeners and related research.
Longitudinal Measurement Invariance of Posttraumatic Stress Disorder in Deployed Marines
Authors: Contractor Ateka A. , Bolton Elisa , Gallagher Matthew W. , Rhodes Charla , Nash William P. , Litz Brett
Published: May 2017

The meaningful interpretation of longitudinal study findings requires temporal stability of the constructs assessed (i.e., measurement invariance). We sought to examine measurement invariance of the construct of posttraumatic stress disorder (PTSD) as based on the Diagnostic and Statistical Manual of Mental Disorders indexed by the PTSD Checklist (PCL) and the Clinician‐Administered PTSD Scale (CAPS) in a sample of 834 Marines with significant combat experience. PTSD was assessed 1‐month predeployment (T0), and again at 1‐month (T1), 5‐months (T2), and 8‐months postdeployment (T3). We tested configural (pattern of item/parcel loadings), metric (item/parcel loadings on latent factors), and scalar (item/parcel‐level severity) invariance and explored sources of measurement instability (partial invariance testing). The T0 best‐fitting emotional numbing model factor structure informed the conceptualization of PTSD's latent factors and parcel formations. We found (1) scalar noninvariance for the construct of PTSD as measured by the PCL and the CAPS, and for PTSD symptom clusters as assessed by the CAPS; and (2) metric noninvariance for PTSD symptom clusters as measured by the PCL. Exploratory analyses revealed factor‐loading and intercept differences from pre‐ to postdeployment for avoidance symptoms, numbing symptoms (mainly psychogenic amnesia and foreshortened future), and the item assessing startle, each of which reduced construct stability. Implications of these findings for longitudinal studies of PTSD are discussed.
Reckless Self‐Destructive Behavior and PTSD in Veterans: The Mediating Role of New Adverse Events
Authors: Lusk Joanna D. , Sadeh Naomi , Wolf Erika J. , Miller Mark W.
Published: May 2017

The addition of self‐destructive and reckless behavior as a symptom of posttraumatic stress disorder (PTSD) in DSM‐5 has stimulated renewed interest in understanding relationships between these behaviors and trauma‐related psychopathology. This study examined the relationship between reckless and self‐destructive behaviors (RSDB), intervening exposure to new adverse events, and later PTSD severity in a sample of trauma‐exposed veterans. At baseline, participants were assessed for RSDB (past 5 years) and current PTSD severity (N = 222). PTSD severity was then reassessed approximately 4 years later (N = 148). Overall, RSDB were reported by 74.4% of the sample, with 61.3% engaging in multiple forms of RSDB. The most commonly endorsed behaviors included alcohol/drug abuse (42.8%), driving while intoxicated (29.4%), gambling (24.7%), and aggression (23.1%). There was a positive correlation between RSDB and PTSD severity at both the baseline (r = .16, p = .031) and follow‐up assessment (r = .24, p = .005). Path models indicated that exposure to new adverse events fully mediated the effect of Time 1 RSDB on PTSD symptoms at Time 2 (indirect association: β = .05, p = .046). Results suggest that RSDB are common among trauma‐exposed veterans and may perpetuate PTSD symptoms by increasing exposure to new adverse events.
Soluble MICA is elevated in pancreatic cancer: Results from a population based case‐control study
Authors: Onyeaghala Guillaume , Nelson Heather H. , Thyagarajan Bharat , Linabery Amy M. , Panoskaltsis‐Mortari Angela , Gross Myron , Anderson Kristin E. , Prizment Anna E.
Published: May 2017

Pancreatic cancer is diagnosed at a late stage and has one of the highest cancer mortality rates in the United States, creating an urgent need for novel early detection tools. A candidate biomarker for use in early detection is the soluble MHC class I‐related chain A (s‐MICA) ligand, which pancreatic tumors shed to escape immune detection. The objective of this study was to define the association between s‐MICA levels and pancreatic cancer, in a population‐based case‐control study. S‐MICA was measured in 143 pancreatic cancer cases and 459 controls. Unconditional logistic regression was used to calculate odds ratio (OR) for pancreatic cancer and 95% confidence intervals (CI). There was a positive association between increasing s‐MICA levels and pancreatic cancer: compared to the lowest tertile, the ORs for pancreatic cancer were 1.25 (95%CI: 0.75‐2.07) and 2.10 (95%CI: 1.29‐3.42) in the second and highest tertiles, respectively (P‐trend = 0.02). Our study supports previous work demonstrating a positive association between plasma s‐MICA levels and pancreatic cancer.
Developmental competence of porcine genome‐edited zygotes
Authors: Gil Maria A. , Martinez Cristina A. , Nohalez Alicia , Parrilla Inmaculada , Roca Jordi , Wu Jun , Ross Pablo J. , Cuello Cristina , Izpisua Juan C. , Martinez Emilio A.
Published: May 2017

Genome editing in pigs has tremendous practical applications for biomedicine. The advent of genome editing technology, with its use of site‐specific nucleases—including ZFNs, TALENs, and the CRISPR/Cas9 system—has popularized targeted zygote genome editing via one‐step microinjection in several mammalian species. Here, we review methods to optimize the developmental competence of genome‐edited porcine embryos and strategies to improve the zygote genome‐editing efficiency in pigs.
Choice of reference measurements affects quantification of long diffusion time behaviour using stimulated echoes
Authors: Kleinnijenhuis Michiel , Mollink Jeroen , Lam Wilfred W. , Kinchesh Paul , Khrapitchev Alexandre A. , Smart Sean C. , Jbabdi Saad , Miller Karla L.
Published: May 2017

Purpose

To demonstrate how reference data affect the quantification of the apparent diffusion coefficient (ADC) in long diffusion time measurements with diffusion‐weighted stimulated echo acquisition mode (DW‐STEAM) measurements, and to present a modification to avoid contribution from crusher gradients in DW‐STEAM.

Methods

For DW‐STEAM, reference measurements at long diffusion times have significant b0 value, because b = 0 cannot be achieved in practice as a result of the need for signal spoiling. Two strategies for acquiring reference data over a range of diffusion times were considered: constant diffusion weighting (fixed‐b0) and constant gradient area (fixed‐q0). Fixed‐b0 and fixed‐q0 were compared using signal calculations for systems with one and two diffusion coefficients, and experimentally using data from postmortem human corpus callosum samples.

Results

Calculations of biexponential diffusion decay show that the ADC is underestimated for reference images with b > 0, which can induce an apparent time‐dependence for fixed‐q0. Restricted systems were also found to be affected. Experimentally, the exaggeration of the diffusion time–dependent effect under fixed‐q0 versus fixed‐b0 was in a range predicted theoretically, accounting for 62% (longitudinal) and 35% (radial) of the time dependence observed in white matter.

Conclusions

Variation in the b‐value of reference measurements in DW‐STEAM can induce artificial diffusion time dependence in ADC, even in the absence of restriction. Magn Reson Med 79:952–959, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Electrophysiologic features of POEMS syndrome compared with MGUS‐related neuropathy
Authors: Kim Hyunjin , Lim Young‐Min , Jin Joo Yea , Yoon Dok Hyun , Suh Cheolwon , Kim Sun‐Young , Jo Jae‐Cheol , Kim Kwang‐Kuk
Published: May 2017

Introduction

Polyneuropathy, organomegaly, endocrinopathy, M‐protein, and skin changes (POEMS) syndrome and monoclonal gammopathy of undetermined significance (MGUS) are paraproteinemic disorders that can cause demyelinating polyneuropathy. Herein we assessed the findings of nerve conduction studies (NCS) in patients with POEMS syndrome and MGUS‐related neuropathy to determine whether the NCS characteristics can help differentiate between these conditions.

Methods

We enrolled 24 POEMS and 37 MGUS‐related neuropathy patients. NCS parameters, including compound muscle action potential (CMAP), motor conduction velocity (MCV), and terminal latency index (TLI), were evaluated.

Results

Compared with MGUS‐related neuropathy patients, POEMS syndrome patients demonstrated a greater reduction in both the upper and lower limb CMAPs and a greater reduction in the median and ulnar MCVs. The TLIs were significantly higher in POEMS patients.

Discussion

NCS can help distinguish POEMS syndrome from MGUS‐related neuropathy. Reduced CMAPs, slow MCVs, and high TLIs are indicative of POEMS syndrome rather than MGUS‐related neuropathy. Muscle Nerve 56: E73–E77, 2017
Data transformation as a means towards dynamic data storage and polyglot persistence
Authors: Vanhove Thomas , Sebrechts Merlijn , Van Seghbroeck Gregory , Wauters Tim , Volckaert Bruno , De Turck Filip
Published: May 2017

Legacy applications have been built around the concept of storing their data in one relational data store. However, with the current differentiation in data store technologies as a consequence of the NoSQL paradigm, new and possibly more performant storage solutions are available to all applications. The concept of dynamic storage makes sure that application data are always stored in the most optimal data store at a given time to increase application performance. Additionally, polyglot persistence aims to push this performance even further by storing each different data type of an application in the data store technology best suited for it. To get legacy applications into dynamic storage and polyglot persistence, schema and data transformations between data store technologies are needed. This usually infers application redesigns as well to support the new data stores. This paper proposes such a transformation approach through a canonical model. It is based on the Lambda architecture to ensure no application downtime is needed during the transformation process, and after the transformation, the application can continue to query in the original query language, thus requiring no application code changes.
Longitudinal Outcomes of Home Care in Korea to Manage Pressure Ulcers
Authors: Lee Eunhee
Published: May 2017

Home care provides preventive, support, and treatment services to economically vulnerable community populations. In this study, we examined the outcomes of a home care program for pressure ulcers (PrUs) in an economically vulnerable group. The 184 participants were admitted with PrUs and received services from a home care agency in South Korea during a study window of 5 years. The changes in PrU staging over time were analyzed in relation to the agency's home care data and the participants’ health data. At enrollment, approximately 60% had a single ulcer; 40% had two or more. Most patients’ ulcers were at stages 3 or 4, and most patients were bedridden. The maximum odds of reduced ulcer size from one measurement point to the next was estimated at 14.3% for ulcers in stages 1 and 2, 33.4% of those in stage 3, and 25.5% of those in stage 4; more than 10% of ulcers healed completely within a year. PrUs were a serious problem in this community‐dwelling economically vulnerable group, and home care played a critical role in providing health care to this population. © 2017 Wiley Periodicals, Inc.
High performance nanocomposites from Ti3SiC2 MAX phase and phthalonitrile resin
Authors: Derradji Mehdi , Henniche Abdelkhalek , Wang Jun , Dayo Abdul Qadeer , Ouyang Jia‐hu , Liu Wen‐bin , Medjahed Aboubakr
Published: May 2017

A new kind of nanocomposites was prepared from a high performance phthalonitrile resin and Ti3SiC2 MAX phase ceramic nanoparticles. The synergistic combination of both phases led to nanocomposites with improved thermal and mechanical properties. For instance, the thermal conductivity and tensile properties of the neat resin were highly enhanced on adding more nanofillers contents. Moreover, the phthalonitrile resin toughness was enhanced by 123% at the maximum nanoparticles loading of 15 vol.%. The experimental investigations were also compared with predictions from Series, Halpin‐Tsai, and Kerner models and a full discussion was provided. A high resolution transmission electron microscope confirmed the ability of the MAX phase to create a conductive network, especially at high nanofillers amounts. SEM analyses of the tensile fractured surfaces revealed positive changes in the morphology, such as an increase in the roughness and amount of hackling as well as the formation of multiple micro‐cracks. The MAX phase also enhanced the thermal stability, stiffness, and glass transition temperature of the neat resin. This work confirms the superiority of the MAX phase ceramics over the traditional ones in enhancing the properties of the phthalonitrile resin and opens the way for further research in the field. POLYM. COMPOS., 39:3705–3711, 2018. © 2017 Society of Plastics Engineers
Dielectric characterization of thermally aged recycled Polyethylene Terephthalate and Polyethylene Naphthalate reinforced with inorganic fillers
Authors: Mebarki Fouzia , David Eric
Published: May 2017

In order to assess the influence of the operating temperature on the dielectric properties of recycled Polyethylene Terephthalate (PET) and Polyethylene Naphthalate (PEN) reinforced with inorganic fillers, a dielectric and thermal investigation was undertaken. Specimens were thermally aged at several temperatures between 90 and 200°C for 360 h. The effect of thermal aging time on dielectric and thermal properties was also investigated. The dielectric response and breakdown strength properties were evaluated. Differential scanning calorimetry (DSC) measurements showed that the degree of crystallinity and the glass transition temperature increased with aging temperature and duration. The data obtained showed that these materials exhibited a good resistance to thermal aging at temperatures below 140°C. Furthermore, it was found that the dielectric strength of the recycled PET and PEN and their composites decreased considerably for temperatures of over 170°C. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers
Path‐Dependent Frost‐Wedging Experiments in Fractured, Low‐Permeability Granite
Authors: Jia Hailiang , Leith Kerry , Krautblatter Michael
Published: May 2017

To investigate the mechanism of frost wedging in fractured low‐porosity bedrock, we monitored the opening of an artificial 4 mm wide and 80 mm deep crack, cut 20 mm from the end of a rectangular granite block. Two freezing protocols were employed – top‐down and bottom‐up, the former consisting of short‐ and long‐term variants, lasting 1 and 53 days, respectively. Our results demonstrate that (i) in 1‐day experiments, maximum crack widening during top‐down freezing is around 0.11 mm, while bottom‐up freezing produces only 0.02 mm of deformation; (ii) neither ice nor water pressure causes measurable irreversible crack widening during 1‐day tests; (iii) irreversible crack widening is only observed following the 53‐day experiment under top‐down freezing. Based on these results, we suggest (i) freezing direction plays a key role in determining the magnitude of crack widening; and (ii) freezing duration could be essential for crack propagation. The fracturing is both time‐dependent and subcritical; thus, persistent freezing in winter could actually be the active period of crack propagation. This allows us to propose a simplified method to calculate ice pressure according to crack widening. Here we show how freezing direction and duration in ice‐filled cracks control the path‐dependent efficacy of frost‐wedging. Copyright © 2017 John Wiley & Sons, Ltd.
Insights into links between autophagy and the ubiquitin system from the structure of LC3B bound to the LIR motif from the E3 ligase NEDD4
Authors: Qiu Yu , Zheng Yumei , Wu Kuen‐Phon , Schulman Brenda A.
Published: May 2017

Members of the LC3/GABARAP family of ubiquitin‐like proteins function during autophagy by serving as membrane linked protein‐binding platforms. Their C‐termini are physically attached to membranes through covalent linkage to primary amines on lipids such as phosphatidylethanolamine, while their ubiquitin‐like fold domains bind “LIR” (LC3‐Interacting Region) sequences found within an extraordinarily diverse array of proteins including regulators of autophagy, adaptors that recruit ubiquitinated cargoes to be degraded, and even proteins controlling processes at membranes that are not associated with autophagy. Recently, LC3/GABARAP proteins were found to bind the ubiquitin E3 ligase NEDD4 to influence ubiquitination associated with autophagy in human cell lines. Here, we use purified recombinant proteins to define LC3B interactions with a specific LIR sequence from NEDD4, present a crystal structure showing atomic details of the interaction, and show that LC3B‐binding can steer intrinsic NEDD4 E3 ligase activity. The data provide detailed molecular insights underlying recruitment of an E3 ubiquitin ligase to phagophores during autophagy.
Stability of active disturbance rejection control for uncertain systems: A Lyapunov perspective
Authors: Aguilar‐Ibañez Carlos , Sira‐Ramirez Hebertt , Acosta José Ángel
Published: May 2017

In this work, we introduce a simple stability analysis to justify, under some suitable assumptions, the active disturbance rejection control method, used in the feedback regulation of a substantially uncertain plant. A criterion is obtained that allows us to define under what conditions closed‐loop stability can be assured. When the plant is mostly unknown, the criterion allows us to guarantee exponential convergence for the output‐feedback regulation problem, in the presence of a constant external perturbation, and practical stability when the external perturbation and the tracking reference signal are both time‐varying. In the latter case, the confinement error can be made as small as desired. To carry out the corresponding stability analysis, we derive the tracking error equation, and the observation error equation. To decouple these error equations, we use the Sylvester equation. Finally, we applied the direct Lyapunov method to analyze the corresponding convergence of the observation error and of the tracking error. Copyright © 2017 John Wiley & Sons, Ltd.
Output feedback regulation of upper triangular nonlinear systems with uncertain time‐varying delays in states and input
Authors: Koo Min‐Sung , Choi Ho‐Lim
Published: May 2017

In this paper, an output feedback controller is studied to regulate a class of upper triangular nonlinear systems with uncertain time‐varying delays. The key features of our considered system are that there are uncertain time‐varying delays in both states and input and the high‐order nonlinearity is in a more relaxed form over the previous results. Theoretical analysis and numerical example are presented to show the benefits of our controller. Copyright © 2017 John Wiley & Sons, Ltd.
Assessment of the environmental quality of two urbanized lotic systems using multiple indicators
Authors: Calderon M. R. , Moglia M. M. , Nievas R. P. , Colombetti P. L. , González S. P. , Jofré M. B.
Published: May 2017

Urbanization impacts ecosystems through loss and fragmentation of habitat, loss of diversity, increase in runoff, and contaminant discharges, and the invasion of exotic species. Potrero de los Funes Village (San Luis, Argentina) is experiencing not only a population increase during summer months due to tourism but also an accelerated growth of its permanent population. In order to evaluate the potential effects of urbanization, the environmental quality of Potrero de los Funes River and Las Chacras Stream was assessed, using physical–chemical and biological indicators. Macroinvertebrates, through the application of the Biotic Index for San Luis Sierras (BISLS), anuran amphibian richness and relative abundance, and riparian vegetation were used as bioindicators. While the Simplified Index of Water Quality (SIWQ) was used to characterize the physical–chemical quality of water at each site. SIWQ and BISLS scores were significantly different between sites (F7,28 = 9.88, p < .001 and F7,28 = 24.18, p < .001, respectively). SIWQ was significantly correlated with BISLS (Spearman correlation coefficient = 0.8, p < .001). Four anuran species were registered along Potrero River, with no significant differences in the intensity of vocalizations between sites. No species were detected in Las Chacras Stream. Average total plant species richness, exotic plants richness, and vegetation cover were higher at the most impaired system, Las Chacras Stream. The principal component analysis showed that the first two principal components (PCs) explained 76.3% of the total variance. PC1, with strong loadings of SIWQ, BISLS, and amphibian richness, was principally driven by chemical water quality and biological conditions. PC2 was mainly determined by plant richness. The chemical and biological water quality of Potrero and Las Chacras is somewhat impaired, being the upper Las Chacras Stream the most compromised area. This study provides information that will certainly be used to manage future impacts of urbanization on aquatic resources.
“Can There be a Full Moon at Daytime?” Young Students Making Sense of Illustrations of the Lunar Phases
Authors: Åberg‐Bengtsson Lisbeth , Karlsson Karl Göran , Ottosson Torgny
Published: May 2017

Teaching and learning situations nowadays typically build on richly illustrated material or multimodal presentations. Under these circumstances, the transparency of images and models used for explaining various phenomena becomes central. The present study deals with 20 Swedish children, 9–12 years old, discussing an illustration meant to show the cause of the different appearances of the Moon in the sky. The students’ task was to place eight numbered moon phases in the lunar orbit in the image. The illustration in question was chosen (a) because it was of a kind frequently used to explain the lunar phases and (b) because the phenomenon is known to be difficult to understand for students of all ages. The analysis leans on historical and sociocultural approaches as well as on multimodal semiotics. The results show that a majority of students were able to make sense of the most central features of the illustration but that very few spontaneously reasoned in a way that could be interpreted as the intended meaning‐making of the cause of the lunar phases. The results also indicate that the simultaneous adoption of two perspectives necessary for understanding the phenomenon was a stumbling block for most of the students.
Genetic Rescue of Mitochondrial and Skeletal Muscle Impairment in an Induced Pluripotent Stem Cells Model of Coenzyme Q10 Deficiency
Authors: Romero-Moya Damià , Santos-Ocaña Carlos , Castaño Julio , Garrabou Gloria , Rodríguez-Gómez José A. , Ruiz-Bonilla Vanesa , Bueno Clara , González-Rodríguez Patricia , Giorgetti Alessandra , Perdiguero Eusebio , Prieto Cristina , Moren-Nuñez Constanza , Fernández-Ayala Daniel J. , Victoria Cascajo Maria , Velasco Iván , Canals Josep Maria , Montero Raquel , Yubero Delia , Jou Cristina , López-Barneo José , Cardellach Francesc , Muñoz-Cánoves Pura , Artuch Rafael , Navas Plácido , Menendez Pablo
Published: May 2017

Coenzyme Q10 (CoQ10) plays a crucial role in mitochondria as an electron carrier within the mitochondrial respiratory chain (MRC) and is an essential antioxidant. Mutations in genes responsible for CoQ10 biosynthesis (COQ genes) cause primary CoQ10 deficiency, a rare and heterogeneous mitochondrial disorder with no clear genotype–phenotype association, mainly affecting tissues with high-energy demand including brain and skeletal muscle (SkM). Here, we report a four-year-old girl diagnosed with minor mental retardation and lethal rhabdomyolysis harboring a heterozygous mutation (c.483G > C (E161D)) in COQ4. The patient’s fibroblasts showed a decrease in [CoQ10], CoQ10 biosynthesis, MRC activity affecting complexes I/II + III, and respiration defects. Bona fide induced pluripotent stem cell (iPSCs) lines carrying the COQ4 mutation (CQ4-iPSCs) were generated, characterized and genetically edited using the CRISPR-Cas9 system (CQ4ed-iPSCs). Extensive differentiation and metabolic assays of control-iPSCs, CQ4-iPSCs and CQ4ed-iPSCs demonstrated a genotype association, reproducing the disease phenotype. The COQ4 mutation in iPSC was associated with CoQ10 deficiency, metabolic dysfunction, and respiration defects. iPSC differentiation into SkM was compromised, and the resulting SkM also displayed respiration defects. Remarkably, iPSC differentiation in dopaminergic or motor neurons was unaffected. This study offers an unprecedented iPSC model recapitulating CoQ10 deficiency-associated functional and metabolic phenotypes caused by COQ4 mutation.
Shrinkage and creep behavior of an alkali‐activated slag concrete
Authors: Ma Jianxin , Dehn Frank
Published: May 2017

In this paper, experimental results about the shrinkage and creep behavior of an alkali‐activated slag concrete (AAS‐concrete) are presented. The autogenous shrinkage of AAS‐concrete is pronounced at a relatively high water to binder ratio of 0.41. The ultimate value of autogenous shrinkage is determined to be higher than that of high‐strength concrete (HSC). The observed self‐desiccation at a later concrete age can be one of the reasons for the autogenous shrinkage. In a drying environment of 65% relative humidity AAS‐concrete exhibits a significantly higher total shrinkage compared to normal‐strength concrete composed of Portland cement.

In the contrary to normal and HSC carbonation shrinkage must not be neglected for AAS‐concrete in the early concrete age. The sum of drying and carbonation shrinkage develops much more rapidly for AAS‐concrete in the first weeks after the beginning of drying. Based on the experimental results the shrinkage behavior of AAS‐concrete cannot be predicted by conventional models. The creep behavior of the AAS‐concrete was investigated under sealed and unsealed conditions. The creep coefficients for both conditions are higher than those calculated when using conventional models.
“If I Can Offer You Some Advice”: Rapport and Data Collection in Interviews Between Adults of Different Ages
Authors: Vasquez‐Tokos Jessica
Published: May 2017

Reflexively analyzing interactions between myself (young adult woman) and 150 adult research participants, I explore how interviewees responded to the interviewer's perceived age in combination with other social identity categories. Addressing a gap in scholarship on adult‐adult interview interactions, this article examines how age gradations, in combination with other axes of similarity or difference, affect researcher‐interviewee rapport and data acquisition. Racial similarity, regardless of age, unlocked access to the topic of race/ethnicity. Age intersected with gender such that women within a decade of the woman interviewer's age assumed similarity and were communicative. In interviews with similarly‐aged heterosexual men, awareness of sexuality inhibited answers around intimacy. With older interviewees, gender similarity bridged the age chasm with women. In contrast, age and gender difference inspired older men to act paternalistically and give unsolicited advice. Even among adults, interviewees' classification of the interviewer's age contours the interactional dynamic, impacts data acquisition, and reproduces social distinctions.
Re: Increased nuchal translucency thickness and risk of neurodevelopmental disorders. S. G. Hellmuth, L. H. Pedersen, C. B. Miltoft, O. B. Petersen, S. Kjærgaard, C. Ekelund and A. Tabor. Ultrasound Obstet Gynecol 2017; 49: 592–598.
Authors: Bilardo C. M.
Published: May 2017

Linked Comment: Ultrasound Obstet Gynecol 2017; 49: 592–598
Improved fixed point iterative method for blade element momentum computations
Authors: Sun Zhenye , Shen Wen Zhong , Chen Jin , Zhu Wei Jun
Published: May 2017

The blade element momentum (BEM) theory is widely used in aerodynamic performance calculations and optimization applications for wind turbines. The fixed point iterative method is the most commonly utilized technique to solve the BEM equations. However, this method sometimes does not converge to the physical solution, especially for the locations near the blade tip and root where the failure rate of the iterative method is high. The stability and accuracy of aerodynamic calculations and optimizations are greatly reduced due to this problem. The intrinsic mechanisms leading to convergence problems are addressed through both theoretical analysis and numerical tests. A term from the BEM equations equals to zero at a critical inflow angle is the source of the convergence problems. When the initial inflow angle is set larger than the critical inflow angle and the relaxation methodology is adopted, the convergence ability of the iterative method will be greatly enhanced. Numerical tests have been performed under different combinations of local tip speed ratio, local solidity, local twist and airfoil aerodynamic data. Results show that the simple iterative methods have a good convergence ability which will improve the aerodynamic or structural design of wind turbines. Copyright © 2017 John Wiley & Sons, Ltd.
Effects of self-attraction and loading at a regional scale: a test case for the Northwest European Shelf
Authors: Irazoqui Apecechea Maialen , Verlaan Martin , Zijl Firmijn , Le Coz Camille , Kernkamp Herman
Published: May 2017

The impact of the self-attraction and loading effect (SAL) in a regional 2D barotropic tidal model has been assessed, a term with acknowledged and well-understood importance for global models but omitted for boundary-forced, regional models, for which the implementation of SAL is non-trivial due to its non-local nature. In order to understand the impact of the lack of SAL effects in a regional scale, we have forced a regional model of the Northwest European Continental Shelf and the North Sea (continental shelf model (CSM)) with the SAL potential field derived from a global model (GTSM), in the form of a pressure field. Impacts have been studied in an uncalibrated setup and with only tidal forcing activated, in order to isolate effects. Additionally, the usually adopted simple SAL parameterization, in which the SAL contribution to the total tide is parameterized as a percentage of the barotropic pressure gradient (typically chosen 10%), is also implemented and compared to the results obtained with a full SAL computation. A significant impact on M2 representation is observed in the English Channel, Irish Sea and the west (UK East coast) and south (Belgian and Dutch Coast) of the North Sea, with an impact of up to 20 cm in vector difference terms. The impact of SAL translates into a consistent M2 amplitude and propagation speeds reduction throughout the domain. Results using the beta approximation, with an optimal domain-wide constant value of 1.5%, show a somewhat comparable impact in phase but opposite direction of the impact in amplitude, increasing amplitudes everywhere. In relative terms, both implementations lead to a reduction of the tidal representation error in comparison with the reference run without SAL, with the full SAL approach showing further impacted, improved results. Although the overprediction of tidal amplitudes and propagation speeds in the reference run might have additional sources like the lack of additional dissipative processes and non-considered bottom friction settings, results show an overall significant impact, most remarkable in tidal phases. After showing evidence of the SAL impact in regional models, the question of how to include this physical process in them in an efficient way arises, since SAL is a non-local effect and depends on the instantaneous water levels over the whole ocean, which is non-trivial to implement.
Adsorption and Micellization of Gemini Surfactants with Diethylammonium Headgroups: Effect of the Spacer Rigidity
Authors: Liu Zhitian , Ge Yifan , Zhang Qi , Gao Xiang , Cai Xiong , Chen Mengyao , Yu Xuechen
Published: May 2017

A series of novel cationic gemini surfactants p‐phenylenedimethylene bis(alkyldiethylammonium) chloride (abbreviated as Gm, m is the carbon numbers of hydrophobic tails) were synthesized. Their surface properties and aggregation behavior were investigated by surface tension, electrical conductivity, steady‐state fluorescence, dynamic light scattering and transmission electron microscopy measurements, and compared with gemini surfactants with a flexible hexanediyl spacer and diethylammonium headgroups [abbreviated as CmC6Cm(Et)]. It was found that Gm reached adsorption equilibrium at the air–water interface at the critical micelle concentration, but CmC6Cm(Et) did not. The packing densities and the aggregation surface charge densities of Gm are less than that of CmC6Cm(Et). Pre‐micellar association occurs in aqueous solutions of gemini surfactants with m ≥ 14. The ability to form pre‐micellar aggregates increases with increasing the length of alkyl chain. Gemini surfactants with rigid p‐xylylene spacer are more prone to form the pre‐micellar aggregates. The rigidity of the spacer of gemini surfactants has little effect on the aggregation micropolarity sensed by pyrene. Only vesicles were found in aqueous solutions of these gemini surfactants, and Gm with p‐xylylene spacer tends to form larger vesicles which have loose structures with low surface charge density.