bluuebunny/crossref_metadata_2025 huggingface dataset:
Permeability of the blood–brain barrier predicts no evidence of disease activity at 2 years after natalizumab or fingolimod treatment in relapsing–remitting multiple sclerosis
Authors: Cramer Stig P. , Simonsen Helle J. , Varatharaj Aravinthan , Galea Ian , Frederiksen Jette L. , Larsson Henrik B. W.
Published: March 2018

Objective

To investigate whether blood–brain barrier (BBB) permeability, as measured by dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI), can provide early detection of suboptimal treatment response in relapsing–remitting multiple sclerosis (RRMS).

Methods

Thirty‐five RRMS patients starting on fingolimod or natalizumab, drugs with a common effect of decreasing lymphocyte influx into the central nervous system, were scanned with DCE‐MRI at 3T prior to treatment and at 3 and 6 months posttreatment. We calculated the influx constant Ki, a measure of BBB permeability, using the Patlak model. Suboptimal treatment response was defined as loss of no evidence of disease activity (NEDA) status after 2 years of treatment.

Results

Subjects with loss of NEDA status at 2 years had a 51% higher mean Ki in normal‐appearing white matter (NAWM) measured after 6 months of treatment, compared to subjects with maintained NEDA status (mean difference = 0.06ml/100g/min, 95% confidence interval [CI] = 0.02–0.09, p = 0.002). Ki in NAWM at 6 months was a good predictor of loss of NEDA status at 2 years (area under the curve = 0.84, 95% CI = 0.70–0.99, p = 0.003), and a value above 0.136ml/100/g/min yielded an odds ratio of 12.4 for suboptimal treatment response at 2 years, with a sensitivity of 73% and a specificity of 82%.

Interpretation

Our results suggest that BBB permeability as measured by DCE‐MRI reliably predicts suboptimal treatment response and is a surrogate marker of the state of health of the BBB. We find a predictive threshold for disease activity, which is remarkably identical in clinically isolated syndrome as previously reported and established RRMS as investigated here. Ann Neurol 2018;83:902–914
Stem cell modeling of mitochondrial parkinsonism reveals key functions of OPA1
Authors: Jonikas Mindaugas , Madill Martin , Mathy Alexandre , Zekoll Theresa , Zois Christos E. , Wigfield Simon , Kurzawa‐Akanbi Marzena , Browne Cathy , Sims David , Chinnery Patrick F. , Cowley Sally A. , Tofaris George K.
Published: March 2018

Objective

Defective mitochondrial function attributed to optic atrophy 1 (OPA1) mutations causes primarily optic atrophy and, less commonly, neurodegenerative syndromes. The pathomechanism by which OPA1 mutations trigger diffuse loss of neurons in some, but not all, patients is unknown. Here, we used a tractable induced pluripotent stem cell (iPSC)‐based model to capture the biology of OPA1 haploinsufficiency in cases presenting with classic eye disease versus syndromic parkinsonism.

Methods

iPSCs were generated from 2 patients with OPA1 haploinsufficiency and 2 controls and differentiated into dopaminergic neurons. Metabolic profile was determined by extracellular flux analysis, respiratory complex levels using immunoblotting, and complex I activity by a colorimetric assay. Mitochondria were examined by transmission electron microscopy. Mitochondrial DNA copy number and deletions were assayed using long‐range PCR. Mitochondrial membrane potential was measured by tetramethylrhodamine methyl ester uptake, and mitochondrial fragmentation was assessed by confocal microscopy. Exome sequencing was used to screen for pathogenic variants.

Results

OPA1 haploinsufficient iPSCs differentiated into dopaminergic neurons and exhibited marked reduction in OPA1 protein levels. Loss of OPA1 caused a late defect in oxidative phosphorylation, reduced complex I levels, and activity without a significant change in the ultrastructure of mitochondria. Loss of neurons in culture recapitulated dopaminergic degeneration in syndromic disease and correlated with mitochondrial fragmentation.

Interpretation

OPA1 levels maintain oxidative phosphorylation in iPSC‐derived neurons, at least in part, by regulating the stability of complex I. Severity of OPA1 disease associates primarily with the extent of OPA1‐mediated fusion, suggesting that activation of this mechanism or identification of its genetic modifiers may have therapeutic or prognostic value. Ann Neurol 2018;83:915–925
Coadsorbate‐Induced Reversal of Solid–Liquid Interface Dynamics
Authors: Rahn Björn , Wen Rui , Deuchler Lukas , Stremme Johannes , Franke Andreas , Pehlke Eckhard , Magnussen Olaf M.
Published: March 2018

Coadsorbed anions are well‐known to influence surface reactivity and dynamics at solid–liquid interfaces. Here we demonstrate that the chemical nature of these spectator species can entirely determine the microscopic dynamic behavior. Quantitative in situ video‐STM data on the surface diffusion of adsorbed sulfur atoms on Cu(100) electrodes in aqueous solution covered by bromide and chloride spectators, respectively, reveal in both cases a strong exponential potential dependence, but with opposite sign. This reversal is highly surprising in view of the isostructural adsorbate arrangement in the two systems. Detailed DFT studies suggest an anion‐induced difference in the sulfur diffusion mechanism, specifically an exchange diffusion on the Br‐covered surface. Experimental evidence for the latter is provided by the observation of Cu vacancy formation in the Br system, which can be rationalized by a side reaction of the sulfur exchange diffusion.
Generation and Rearrangement of N,O‐Dialkenylhydroxylamines for the Synthesis of 2‐Aminotetrahydrofurans
Authors: Son Jongwoo , Reidl Tyler W. , Kim Ki Hwan , Wink Donald J. , Anderson Laura L.
Published: March 2018

A new diastereoselective route to 2‐aminotetrahydrofurans has been developed from N,O‐dialkenylhydroxylamines. These intermediates undergo a spontaneous C−C bond‐forming [3,3]‐sigmatropic rearrangement followed by a C−O bond‐forming cyclization. A copper‐catalyzed N‐alkenylation of an N‐Boc‐hydroxylamine with alkenyl iodides, and a base‐promoted addition of the resulting N‐hydroxyenamines to an electron‐deficient allene, provide modular access to these novel rearrangement precursors. The scope of this de novo synthesis of simple nucleoside analogues has been explored to reveal trends in diastereoselectivity and reactivity. In addition, a base‐promoted ring‐opening and Mannich reaction has been discovered to covert 2‐aminotetrahydrofurans to cyclopentyl β‐aminoacid derivatives or cyclopentenones.
Two‐Dimensional Fullerene Assembly from an Exfoliated van der Waals Template
Authors: Lee Kihong , Choi Bonnie , Plante Ilan Jen‐La , Paley Maria V. , Zhong Xinjue , Crowther Andrew C. , Owen Jonathan S. , Zhu Xiaoyang , Roy Xavier
Published: March 2018

Two‐dimensional (2D) materials are commonly prepared by exfoliating bulk layered van der Waals crystals. The creation of synthetic 2D materials from bottom‐up methods is an important challenge as their structural flexibility will enable chemists to tune the materials properties. A 2D material was assembled using C60 as a polymerizable monomer. The C60 building blocks are first assembled into a layered solid using a molecular cluster as structure director. The resulting hierarchical crystal is used as a template to polymerize its C60 monolayers, which can be exfoliated down to 2D crystalline nanosheets. Derived from the parent template, the 2D structure is composed of a layer of inorganic cluster, sandwiched between two monolayers of polymerized C60. The nanosheets can be transferred onto solid substrates and depolymerized by heating. Electronic absorption spectroscopy reveals an optical gap of 0.25 eV, narrower than that of the bulk parent crystalline solid.
Tunable Pentapeptide Self‐Assembled β‐Sheet Hydrogels
Authors: Clarke David E. , Parmenter Christopher D. J. , Scherman Oren A.
Published: March 2018

Oligopeptide‐based supramolecular hydrogels hold promise in a range of applications. The gelation of these systems is hard to control, with minor alterations in the peptide sequence significantly influencing the self‐assembly process. We explored three pentapeptide sequences with different charge distributions and discovered that they formed robust, pH‐responsive hydrogels. By altering the concentration and charge distribution of the peptide sequence, the stiffness of the hydrogels could be tuned across two orders of magnitude (2–200 kPa). Also, through reassembly of the β‐sheet interactions the hydrogels could self‐heal and they demonstrated shear‐thin behavior. Using spectroscopic and cryo‐imaging techniques, we investigated the relationship between peptide sequence and molecular structure, and how these influence the mechanical properties of the hydrogel. These pentapeptide hydrogels with tunable morphology and mechanical properties have promise in tissue engineering, injectable delivery vectors, and 3D printing applications.
Dissipative Synthetic DNA‐Based Receptors for the Transient Loading and Release of Molecular Cargo
Authors: Del Grosso Erica , Amodio Alessia , Ragazzon Giulio , Prins Leonard J. , Ricci Francesco
Published: March 2018

Supramolecular chemistry is moving into a direction in which the composition of a chemical equilibrium is no longer determined by thermodynamics but by the efficiency with which kinetic states can be populated by energy consuming processes. Herein, we show that DNA is ideally suited for programming chemically fueled dissipative self‐assembly processes. Advantages of the DNA‐based systems presented in this study include a perfect control over the activation site for the chemical fuel in terms of selectivity and affinity, highly selective fuel consumption that occurs exclusively in the activated complex, and a high tolerance for the presence of waste products. Finally, it is shown that chemical fuels can be used to selectively activate different functions in a system of higher complexity embedded with multiple response pathways.
Carbon‐Electrode‐Tailored All‐Inorganic Perovskite Solar Cells To Harvest Solar and Water‐Vapor Energy
Authors: Duan Jialong , Hu Tianyu , Zhao Yuanyuan , He Benlin , Tang Qunwei
Published: March 2018

Moisture is the worst enemy for state‐of‐the‐art perovskite solar cells (PSCs). However, the flowing water vapor within nanoporous carbonaceous materials can create potentials. Therefore, it is a challenge to integrate water vapor and solar energies into a single PSC device. We demonstrate herein all‐inorganic cesium lead bromide (CsPbBr3) solar cells tailored with carbon electrodes to simultaneously harvest solar and water‐vapor energy. Upon interfacial modification and plasma treatment, the bifunctional PSCs yield a maximum power conversion efficiency up to 9.43 % under one sun irradiation according to photoelectric conversion principle and a power output of 0.158 μW with voltage of 0.35 V and current of 0.45 μA in 80 % relative humidity through the flowing potentials at the carbon/water interface. The initial efficiency is only reduced by 2 % on exposing the inorganic PSC with 80 % humidity over 40 days. The successful realization of physical proof‐of‐concept multi‐energy integrated solar cells provides new opportunities of maximizing overall power output.
Enzymatic Formation of a Skipped Methyl‐Substituted Octaprenyl Side Chain of Longestin (KS‐505a): Involvement of Homo‐IPP as a Common Extender Unit
Authors: Ozaki Taro , Shinde Sandip S. , Gao Lei , Okuizumi Ryo , Liu Chengwei , Ogasawara Yasushi , Lei Xiaoguang , Dairi Tohru , Minami Atsushi , Oikawa Hideaki
Published: March 2018

Longestin (KS‐505a), a specific inhibitor of phosphodiesterase, is a meroterpenoid that consists of a unique octacyclic terpene skeleton with branched methyl groups at unusual positions (C1 and C12). Biochemical analysis of Lon23, a methyltransferase involved in the biosynthesis of longestin, demonstrated that it methylates homoisopentenyl diphosphate (homo‐IPP) to afford (3Z)‐3‐methyl IPP. This compound, along with IPP, is selectively accepted as extender units by Lon22, a geranylgeranyl diphosphate (GGPP) synthase homologue, to yield dimethylated GGPP (dmGGPP). The absolute configuration of dmGGPP was determined to be (4R,12R) by degradation and chiral GC analysis. These findings allowed us to propose an enzymatic sequence for key steps of the biosynthetic pathway of the unusual homoterpenoid longestin.
Redox‐Divergent Synthesis of Fluoroalkylated Pyridines and 2‐Pyridones through Cu‐Catalyzed N−O Cleavage of Oxime Acetates
Authors: Bai Dachang , Wang Xueli , Zheng Guangfan , Li Xingwei
Published: March 2018

Cu‐catalyzed redox‐divergent [3+3] coupling of oxime esters with β‐CF3 enones and acrylates is described. This redox‐neutral coupling with enones and acrylates affords trifluoromethylated pyridines and pyridones, respectively. Under reductive conditions, difluoromethylated pyridines, difluoromethlated pyridones, and trifluoromethylated dihydropyridones are obtained. The reactions occur under mild conditions with broad substrate scope and regio/redox selectivity.
How Changing the Bridgehead Can Affect the Properties of Tripodal Ligands
Authors: Plajer Alex J. , Colebatch Annie L. , Rizzuto Felix J. , Pröhm Patrick , Bond Andrew D. , García‐Rodríguez Raúl , Wright Dominic S.
Published: March 2018

Although a multitude of studies have explored the coordination chemistry of classical tripodal ligands containing a range of main‐group bridgehead atoms or groups, it is not clear how periodic trends affect ligand character and reactivity within a single ligand family. A case in point is the extensive family of neutral tris‐2‐pyridyl ligands E(2‐py)3 (E=C−R, N, P), which are closely related to archetypal tris‐pyrazolyl borates. With the 6‐methyl substituted ligands E(6‐Me‐2‐py)3 (E=As, Sb, Bi) in hand, the effects of bridgehead modification alone on descending a single group in the periodic table were assessed. The primary influence on coordination behaviour is the increasing Lewis acidity (electropositivity) of the bridgehead atom as Group 15 is descended, which not only modulates the electron density on the pyridyl donor groups but also introduces the potential for anion selective coordination behaviour.
Accessing Frustrated Lewis Pair Chemistry from a Spectroscopically Stable and Classical Lewis Acid‐Base Adduct
Authors: Johnstone Timothy C. , Wee Gabriel N. J. H. , Stephan Douglas W.
Published: March 2018

B(C6F5)3 and P(MeNCH2CH2)3N form a classical Lewis adduct, (C6F5)3BP(MeNCH2CH2)3N. Although (C6F5)3BP(MeNCH2CH2)3N does not exhibit spectroscopic evidence of dissociation into its constituent acid and base, products of frustrated Lewis pair (FLP) addition reactions are seen with PhNCO, PhCH2N3, PhNSO, and CO2. Computational studies show that thermal access to the dissociated acid and base permits FLP reactivity to proceed. These results demonstrate that FLP reactivity extends across the entire continuum of equilibria governing Lewis acid‐base adducts.
Eisenkatalysierte C‐O/C‐O‐Bindungsmetathese von aliphatischen Ethern
Authors: Biberger Tobias , Makai Szabolcs , Lian Zhong , Morandi Bill
Published: March 2018

Metathesereaktionen von Alkenen und Alkinen sind sicherlich die bestentwickelten Klassen von Metathesereaktionen für den Aufbau molekularer Komplexität. Demgegenüber ist das Verhalten von Einfachbindungen in Bezug auf Metathesereaktionen recht wenig erforscht, vor allem im Hinblick auf präparativ wichtige Ringschlussreaktionen. Hier wird eine Eisen‐katalysierte Ringschlussmetathese von aliphatischen Diethern vorgestellt, die für den raschen Aufbau von Tetrahydrofuranen, Tetrahydropyranen, Morpholinen und Dioxanen angewendet werden kann. Diese Transformation verläuft offenbar über cyclische Oxonium‐Intermediate.
Valency‐Controlled Framework Nucleic Acid Signal Amplifiers
Authors: Liu Qi , Ge Zhilei , Mao Xiuhai , Zhou Guobao , Zuo Xiaolei , Shen Juwen , Shi Jiye , Li Jiang , Wang Lihua , Chen Xiaoqing , Fan Chunhai
Published: March 2018

Weak ligand–receptor recognition events are often amplified by recruiting multiple regulatory biomolecules to the action site in biological systems. However, signal amplification in in vitro biomimetic systems generally lack the spatiotemporal regulation in vivo. Herein we report a framework nucleic acid (FNA)‐programmed strategy to develop valence‐controlled signal amplifiers with high modularity for ultrasensitive biosensing. We demonstrated that the FNA‐programmed signal amplifiers could recruit nucleic acids, proteins, and inorganic nanoparticles in a stoichiometric manner. The valence‐controlled signal amplifier enhanced the quantification ability of electrochemical biosensors, and enabled ultrasensitive detection of tumor‐relevant circulating free DNA (cfDNA) with sensitivity enhancement of 3–5 orders of magnitude and improved dynamic range.
Electrooxidative Ruthenium‐Catalyzed C−H/O−H Annulation by Weak O‐Coordination
Authors: Qiu Youai , Tian Cong , Massignan Leonardo , Rogge Torben , Ackermann Lutz
Published: March 2018

Electrocatalysis has been identified as a powerful strategy for organometallic catalysis, and yet electrocatalytic C−H activation is restricted to strongly N‐coordinating directing groups. The first example of electrocatalytic C−H activation by weak O‐coordination is presented, in which a versatile ruthenium(II) carboxylate catalyst enables electrooxidative C−H/O−H functionalization for alkyne annulations in the absence of metal oxidants; thereby exploiting sustainable electricity as the sole oxidant. Mechanistic insights provide strong support for a facile organometallic C−H ruthenation and an effective electrochemical reoxidation of the key ruthenium(0) intermediate.
Copper‐Mediated Reversible Deactivation Radical Polymerization in Aqueous Media
Authors: Jones Glen R. , Anastasaki Athina , Whitfield Richard , Engelis Nikolaos , Liarou Evelina , Haddleton David M.
Published: March 2018

Key advances within the past 10 years have transformed copper‐mediated radical polymerization from a technique which was not very tolerant of protic media into a range of closely related processes capable of controlling the polymerization of a wide range of monomers in pure water at ppm catalyst loadings. This approach has afforded water‐soluble macromolecules of desired molecular weight, architecture, and chemical functionality, with applications ranging from drug delivery to oil processing. In this Review we highlight and critically evaluate the synthetic methods that have been developed to control radical polymerization in water by using copper complexes as well as identify future areas of interest and challenges still to be overcome.
Iron‐Catalyzed Ring‐Closing C−O/C−O Metathesis of Aliphatic Ethers
Authors: Biberger Tobias , Makai Szabolcs , Lian Zhong , Morandi Bill
Published: March 2018

Among all metathesis reactions known to date in organic chemistry, the metathesis of multiple bonds such as alkenes and alkynes has evolved into one of the most powerful methods to construct molecular complexity. In contrast, metathesis reactions involving single bonds are scarce and far less developed, particularly in the context of synthetically valuable ring‐closing reactions. Herein, we report an iron‐catalyzed ring‐closing metathesis of aliphatic ethers for the synthesis of substituted tetrahydropyrans and tetrahydrofurans, as well as morpholines and polycyclic ethers. This transformation is enabled by a simple iron catalyst and likely proceeds via cyclic oxonium intermediates.
Mapping the Relationship between Glycosyl Acceptor Reactivity and Glycosylation Stereoselectivity
Authors: van der Vorm Stefan , van Hengst Jacob M. A. , Bakker Marloes , Overkleeft Herman S. , van der Marel Gijsbert A. , Codée Jeroen D. C.
Published: March 2018

The reactivity of both coupling partners—the glycosyl donor and acceptor—is decisive for the outcome of a glycosylation reaction, in terms of both yield and stereoselectivity. Where the reactivity of glycosyl donors is well understood and can be controlled through manipulation of the functional/protecting‐group pattern, the reactivity of glycosyl acceptor alcohols is poorly understood. We here present an operationally simple system to gauge glycosyl acceptor reactivity, which employs two conformationally locked donors with stereoselectivity that critically depends on the reactivity of the nucleophile. A wide array of acceptors was screened and their structure–reactivity/stereoselectivity relationships established. By systematically varying the protecting groups, the reactivity of glycosyl acceptors can be adjusted to attain stereoselective cis‐glucosylations.
Novel interpenetrating 3D network polyaniline/phenolic aerogel with combined thermal and electrical performances
Authors: Yao Rui , Yao Zhengjun , Zhou Jintang
Published: March 2018

A novel interpenetrating three‐dimensional (3D) network polyaniline/phenolic (AP/RF) aerogel was prepared via a three‐step method. Micro‐, thermal, and electrical analyses were conducted for analyzing the pore morphology, thermal, and electrical performance of the aerogel. From the experimental results, AP/RF aerogel prepared by a three‐step compound method and freeze‐drying exhibited an interpenetrating 3D network structure with nanopores. In addition, compared with single AP aerogel, AP/RF aerogel had lower heat conductivity and higher heat‐resistance. What's more, it exhibited superior electrical performance as compared with that of RF aerogel. In general, AP/RF aerogel with low heat conductivity [0.022 W/(m K)], high heat resistance, electrical conductivity (0.09 S/cm), and specific capacitance (420 F/g) exhibited more excellent thermal and electrical comprehensive performance than single AP or RF aerogels. It will have good application prospect in the fields of electrical components. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45953.
Dynamic rheological behavior of poly(ether ketone ketone) from solid state to melt state
Authors: Coulson Mike , Quiroga Cortés Luis , Dantras Eric , Lonjon Antoine , Lacabanne Colette
Published: March 2018

High performance thermoplastic poly(ether ketone ketone) (PEKK) polymers with various meta phenyl links ratio were investigated by dynamical mechanical analysis. Analyses were carried out in a wide range of temperature from solid state (torsion rectangular mode) to the melt state (torsion parallel plates mode) as function of thermal history and environmental conditions. In the solid state, this study was focused on the secondary relaxations in the vitreous state. A complementary investigation conducted with different poly(aryl ether ketones) allowed us to propose a molecular interpretation of PEKK sub‐vitreous relaxations. In the molten state, storage modulus (G′), loss modulus (G″), storage viscosity (η′), and loss viscosity (η″) were studied to determine zero shear‐rate viscosity (η0) and thermal activation energy Ea. Master curves were built and the shift factor aT was determined. Thermal activation energies were extracted from an Arrhenius model on the shift factor temperature's dependency. Finally, Ea and η0 were determined thanks to the dynamic viscosity fit with Cross model and Cole–Cole representation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46456.
Development of antimicrobial‐loaded polyurethane films for drug‐eluting catheters
Authors: Barde Mehul , Davis Montoia , Rangari Shivani , Mendis Hajeewaka C. , De La Fuente Leonardo , Auad Maria L.
Published: March 2018

To prepare antibacterial, polymeric catheters for preventing catheter‐induced infections, sulfathiazole was loaded into polyurethane by solubilizing with solvents and the resultant films were cast. Fourier transform infrared spectroscopy confirmed the presence of sulfathiazole in the drug‐loaded polyurethane films. The thermal and mechanical properties of the films were assessed using differential scanning calorimetry and dynamic mechanical analysis. The drug‐loaded films were immersed in constantly stirred, deionized water at 37 °C for in vitro drug release study. The experimental data obtained from the in vitro drug release study were fit into mathematical models. Antibacterial efficiency of released sulfathiazole was evaluated by Escherichia coli growth inhibition test. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46467.
Vesicular and micellar self‐assembly of stimuli‐responsive poly(N‐isopropyl acrylamide‐b‐9‐anthracene methyl methacrylate) amphiphilic diblock copolymers
Authors: Pawar Kishor , Kutcherlapati S. N. Raju , Yeole Niranjan , Hundiwale Dilip , Jana Tushar
Published: March 2018

Dually responsive amphiphilic diblock copolymers consisting of hydrophilic poly(N‐isopropyl acrylamide) [poly(NIPAAm)] and hydrophobic poly(9‐anthracene methyl methacrylate) were synthesized by reversible addition fragmentation chain‐transfer (RAFT) polymerization with 3‐(benzyl sulfanyl thiocarbonyl sulfanyl) propionic acid as a chain‐transfer agent. In the first step, the poly(NIPAAm) chain was grown to make a macro‐RAFT agent, and in the second step, the chain was extended by hydrophobic 9‐anthryl methyl methacrylate to yield amphiphilic poly(N‐isopropyl acrylamide‐b‐9‐anthracene methyl methacrylate) block copolymers. The formation of copolymers with three different hydrophobic block lengths and a fixed hydrophilic block was confirmed from their molecular weights. The self‐assembly of these copolymers was studied through the determination of the lower critical solution temperature and critical micelle concentration of the copolymers in aqueous solution. The self‐assembled block copolymers displayed vesicular morphology in the case of the small hydrophobic chain, but the morphology gradually turned into a micellar type when the hydrophobic chain length was increased. The variations in the length and chemical composition of the blocks allowed the tuning of the block copolymer responsiveness toward both the pH and temperature. The resulting self‐assembled structures underwent thermally induced and pH‐induced morphological transitions from vesicles to micelles and vice versa in aqueous solution. These dually responsive amphiphilic diblock copolymers have potential applications in the encapsulation of both hydrophobic and hydrophilic drug molecules, as evidenced from the dye encapsulation studies. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46474.
Synthesis of a novel sulfonated poly(amide‐imide) and its application in preparation of ultrafiltration PES membranes as a modifier
Authors: Rezania Jafar , Vatanpour Vahid , Hayatipour Moahammad , Shockravi Abbas , Ehsani Morteza
Published: March 2018

Sulfonated poly(amide‐imide) (SPAI) copolymer was synthesized, characterized, and blended into poly(ether sulfone) (PES)/dimethylacetamide casting solutions to prepare ultrafiltration membranes. Different weight ratios of the copolymer (0–10 wt %) were mixed in the PES casting solution. The analyses of contact angle and attenuated total reflection‐Fourier transform infrared spectra were used to study hydrophilicity and physicochemical properties of the membrane surface, respectively. The membranes were further characterized by scanning electron microscopy images, ultrafiltration performance, and fouling analyses. The outcomes showed that addition of the SPAI in the PES matrix improved considerably the membranes hydrophilicity. Moreover, with increasing SPAI concentration, the porosity, flux recovery ratio, and pure water permeability of the modified membranes were improved. The pure water flux was increased from 3.6 to 12.4 kg/m2 h by increasing 2 wt % SPAI. The antifouling property of the modified PES membranes against bovine serum albumin, tested by a dead‐end filtration setup revealed that bovine serum albumin rejection of the obtained membrane was also enhanced and the antifouling properties of the blending membranes were improved. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46477.
Enhanced CO2 separation performance by PVA/PEG/silica mixed matrix membrane
Authors: Barooah Mridusmita , Mandal Bishnupada
Published: March 2018

This article focused on segregation of low concentration CO2 from CO2/N2 mixture gas by implementing high‐performance facilitated transport mixed matrix membranes (MMMs) in large‐scale carbon capture techniques. These advanced, novel CO2‐selective membrane materials were developed by embedding silica nanoparticles at different loading into the poly(vinyl alcohol) (PVA)/poly(ethylene glycol) (PEG) matrix using solution casting. In situ sol–gel technique was applied for the synthesis of the hydrophilic SiO2 nanoparticles. The compatibility of filler‐polymer matrix plays a crucial role in the optimization of the membrane performance. The dispersion and interaction of the filler into the polymer matrix were confirmed by thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, X‐ray diffraction, field emission scanning electron microscopy, contact angle tests, and swelling ratio analysis. Field emission scanning electron microscopy analysis of the synthesized MMMs established the homogeneous dispersion of the fillers in the polymer matrix. Owing to its good compatibility with PVA/PEG matrix, the inclusion of fillers significantly increased the overall separation efficiency of CO2 within the membrane. Compared to pristine PVA/PEG membrane, PVA/PEG/silica membrane with 3.34 wt % silica loading showed pronounced improvement in its gas separation properties with 78% augmentation in CO2 permeability and 45% enhancement in CO2/N2 selectivity for fixed conditions pertaining to sweep side water flow rate of 0.04 mL/min and 100 °C temperature. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46481.
The use of amylose‐rich starch nanoparticles in emulsion polymerization
Authors: Cummings Shidan , Cunningham Michael , Dubé Marc A.
Published: March 2018

Regenerated starch nanoparticles (RSNPs) produced from dent corn, an amylose‐rich source of starch, are added to an emulsion polymerization. To reduce or eliminate the challenges of polymerizing in the presence of amylose‐rich starch, a seeded, semibatch, monomer‐starved approach is used. To prevent the accumulation of water soluble amylose in the aqueous phase, reaction with a hydrophobic compatibilizing monomer, butyl acrylate, is used prior to the primary butyl acrylate/methyl methacrylate/acrylic acid feed. In addition, an elevated initiator concentration is used in the seed stage to reduce the molecular weight of the soluble starch and promote grafting. The procedure yields a 100.0 cp latex with 40 wt % solids, 25 wt % RSNP loading, and 40 wt % incorporation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46485.
Electrospinning polymer blend of PLA and PBAT: Electrospinnability–solubility map and effect of polymer solution parameters toward application as antibiotic‐carrier mats
Authors: Khatsee Sarunphat , Daranarong Donraporn , Punyodom Winita , Worajittiphon Patnarin
Published: March 2018

Electrospinning of a biodegradable polymer blend of poly(lactic acid) (PLA) and poly(butylene adipate‐co‐terephthalate) (PBAT) is reported for the first time. Effects of several solution parameters on electrospinning are explored, including types of single and binary solvents, binary solvent mixing ratio, polymer blend concentration, polymer blending ratio, and loading content of tetrabutyl titanate as a compatibilizer. An electrospinnability–solubility map of the PLA/PBAT blend is firstly developed for the facile selection of a suitable binary solvent system, thus simplifying the laborious, time‐consuming, trial‐and‐error process. A particular binary solvent system derived from good and non‐solvent serves as the most suitable medium for the successful preparation of homogeneous bead‐free electrospun PLA/PBAT nanofibers. It is revealed that the compatibilizer acts not only as a diameter size tuner for the PLA/PBAT fibers but also as a mechanical property enhancer for the immiscible PLA/PBAT electrospun mats. Moreover, the antibacterial activity of the drug‐loaded PLA/PBAT fibrous mats suggests their potential application as antibiotic‐carrier mats. Preparation of the composite mats comprising bead‐free fibers with an average size at sub‐micrometer scale is also demonstrated, additionally promoting the possibility of using the PLA/PBAT‐based electrospun mats as a matrix of various additives for a wide range of applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46486.
Crystallization kinetics study of dynamically vulcanized PA6/NBR/HNTs nanocomposites by nonisothermal differential scanning calorimetry
Authors: Paran Seyed Mohammad Reza , Vahabi Henri , Ducos Franck , Formela Krzysztof , Zarrintaj Payam , Laachachi Abdelghani , Lopez Cuesta José‐Marie , Saeb Mohammad Reza
Published: March 2018

Investigation of crystallization behavior and kinetics of thermoplastic elastomer nanocomposites was the subject of limited works because of complexities associated with semiexperimental modeling of such phenomenon in a system containing components having completely different behavior in the molten state. Nonisothermal crystallization kinetics of dynamically vulcanized PA6/NBR/HNTs thermoplastic elastomer nanocomposites was mathematically modeled applying well‐known Avrami, Ozawa, and Mo theoretical models to the differential scanning calorimetry data gathered at various cooling rates. It was found that HNTs contribute as nucleating agents to the crystallization kinetics and cause acceleration of crystallization. Activation energy of the crystallization was calculated by correlating the crystallization peak temperature with the cooling rate using Kissinger model. It was found that Mo equation could properly describe nonisothermal crystallization kinetics of the PA6/NBR/HNTs thermoplastic elastomer nanocomposites. This was recognized from the obtained parameters of Mo equation in terms of HNTs loading level, which suggested a higher rate for dynamic crystallization. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46488.
Potential of DMSO as greener solvent for PES ultra‐ and nanofiltration membrane preparation
Authors: Evenepoel Nicholas , Wen Shufen , Tilahun Tsehaye Misgina , Van der Bruggen Bart
Published: March 2018

In this article, the performance of polyethersulfone (PES) ultra‐ and nanofiltration membranes, prepared with the non‐toxic solvent dimethyl sulfoxide (DMSO), was investigated. The membranes were prepared by immersion precipitation via phase inversion. Experimental results proved that DMSO is a better alternative to N‐methyl‐2‐pyrrolidone (NMP) as solvent for PES ultrafiltration membranes as the membranes had a higher permeability and rejection of bovine serum albumin (BSA). An explanation was found based on experimental cloud point data and scanning electron microscopy images showing the morphology. The rejection of BSA and rose Bengal (RB) was proportional to the polymer concentration. On the contrary, the permeability decreased with increasing polymer concentration. For a casting thickness of 250 µm, an optimal balance between permeability and rejection of macromolecules for ultrafiltration was found at 24 wt % PES. The permeability was inversely proportional to the casting thickness, but a small decrease in rejection was observed when lowering the thickness. A good balance between permeability and rejection of RB was found, using a reference nanofiltration membrane of 28.5 wt % PES with 150 µm casting thickness. This membrane achieved a RB rejection of 95.3% and a pure water flux of 2.03 L m−2 h−1 bar−1. The membrane thickness and polymer concentration did not have a clear influence on the hydrophilicity of the membranes. It can be concluded that DMSO is a benign alternative as compared to traditional solvents such as NMP and also results in better PES membrane performances. DMSO is a perfectly suitable solvent for ultrafiltration applications and has potential to be used for nanofiltration applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46494.
Hierarchical self‐assembly of Y‐shaped amphiphilic triblock polyurethane/poly(acrylic acid) complexes: Giant vesicles, vesicles, 3D network, and bulk structures
Authors: Lai Shuangquan , Jin Yong , Li Hanping , Sun Xiaopeng , Pan Jiezhou
Published: March 2018

A simple and effective approach to induce hierarchical self‐assembly of Y‐shaped amphiphilic triblock polyurethane/poly(acrylic acid) complexes system in aqueous media is reported here. Hydrogen bonding interactions and electrostatic repulsive forces, which can be controlled by regulating the pH condition of complexes solution, were the main driving forces to induce morphological transitions. With the gradual decrease of pH value, a variety of micro‐/nanostructures including giant vesicles, small vesicles, multi‐layer three‐dimensional (3D) porous network structures and “bulk” structures were successively obtained. Among these structures, the micron‐scale multi‐layer 3D porous network structure formed from block copolymer/homopolymer complexes was rarely reported. Therefore, this research demonstrates that the hierarchical self‐assembly of polymers complexes in aqueous media is a viable approach to construct different interesting micro‐/nanostructure assemblies, and supplies a new clue for the fabrication of multi‐layer 3D porous network structures. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46503.
Ultrasmall Ag nanocrystals supported on chitosan/PVA nanofiber mats with bifunctional properties
Authors: Wang Dong , Lu Qifang , Wei Mingzhi , Guo Enyan
Published: March 2018

Bifunctional nanofiber mats consisting of chitosan (CS), poly(vinyl alcohol) (PVA), and silver nanocrystals (Ag NCs) have been fabricated by a facile electrospinning method. The formation and presence of Ag NCs supported on CS/PVA nanofibers are confirmed by ultraviolet‐visible spectroscopy and X‐ray diffraction. The morphology of the samples is characterized by transmission electron microscopy and scanning electron microscopy. The prepared Ag NCs/CS/PVA nanofiber mats show pronounced antibacterial activity against Escherichia coli and excellent filtration property for suspended particulate matter (SPM) particles. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46504.
A guide to sequence your favorite plant genomes
Authors: Li Fay‐Wei , Harkess Alex
Published: March 2018

With the rapid development of sequencing technology and the plummeting cost, assembling whole genomes from non‐model plants will soon become routine for plant systematists and evolutionary biologists. Here we summarize and compare several of the latest genome sequencing and assembly approaches, offering a practical guide on how to approach a genome project. We also highlight certain precautions that need to be taken before investing time and money into a genome project.
Guiding Low Spatial Ability Individuals through Visual Cueing: The Dual Importance of Where and When to Look
Authors: Roach Victoria A. , Fraser Graham M. , Kryklywy James H. , Mitchell Derek G.V. , Wilson Timothy D.
Published: March 2018

Research suggests that spatial ability may predict success in complex disciplines including anatomy, where mastery requires a firm understanding of the intricate relationships occurring along the course of veins, arteries, and nerves, as they traverse through and around bones, muscles, and organs. Debate exists on the malleability of spatial ability, and some suggest that spatial ability can be enhanced through training. It is hypothesized that spatial ability can be trained in low‐performing individuals through visual guidance. To address this, training was completed through a visual guidance protocol. This protocol was based on eye‐movement patterns of high‐performing individuals, collected via eye‐tracking as they completed an Electronic Mental Rotations Test (EMRT). The effects of guidance were evaluated using 33 individuals with low mental rotation ability, in a counterbalanced crossover design. Individuals were placed in one of two treatment groups (late or early guidance) and completed both a guided, and an unguided EMRT. A third group (no guidance/control) completed two unguided EMRTs. All groups demonstrated an increase in EMRT scores on their second test (P < 0.001); however, an interaction was observed between treatment and test iteration (P = 0.024). The effect of guidance on scores was contingent on when the guidance was applied. When guidance was applied early, scores were significantly greater than expected (P = 0.028). These findings suggest that by guiding individuals with low mental rotation ability “where” to look early in training, better search approaches may be adopted, yielding improvements in spatial reasoning scores. It is proposed that visual guidance may be applied in spatial fields, such as STEMM (science, technology, engineering, mathematics and medicine), surgery, and anatomy to improve student's interpretation of visual content. Anat Sci Educ. © 2018 American Association of Anatomists.
Early and prolonged opportunities to practice suturing increases medical student comfort with suturing during clerkships: Suturing during cadaver dissection
Authors: Manning Edward P. , Mishall Priti L. , Weidmann Maxwell D. , Flax Herschel , Lan Sam , Erlich Mark , Burton William B. , Olson Todd R. , Downie Sherry A.
Published: March 2018

Medical students are expected to perform common procedures such as suturing on patients during their third‐year clerkships. However, these experiences are often viewed by medical students as stressors rather than opportunities for learning. The source of this stress is the lack of instruction on common procedures prior to being asked to observe or perform the procedure on a patient. First‐time exposures to procedures in stressful environments may result in decreased confidence in medical students and decrease the frequency with which they perform these procedures in the future. The authors sought to change this paradigm by: (1) introducing a suturing module to first‐year medical students in the context of the anatomy dissection laboratory and (2) measuring its effects on student attitudes and behavior over the course of their third‐year clerkships when they encounter patients. The authors found that early and prolonged introduction to suturing was associated with increased student confidence relative to suturing a patient. Participation in the suturing module was associated with increased student confidence in identifying suturing instruments (P < 0.001) and suturing patients (P = 0.013). Further it positively affected their behavior as demonstrated by increased performance of suturing events from students exposed to the suturing module. (P < 0.001) This study demonstrates that early and prolonged opportunities to practice a procedural skill in a low‐stress environment increases student confidence during patient interactions and alters student behavior.
Boron Tribromide‐Assisted Chiral Phosphoric Acid Catalysts for Enantioselective [2+2] Cycloaddition
Authors: Sakamoto Tatsuhiro , Mochizuki Takuya , Goto Yuta , Hatano Manabu , Ishihara Kazuaki
Published: March 2018

BBr3‐assisted chiral phosphoric acid catalysts for enantioselective [2+2] cycloaddition were developed. The reactions of phenyl vinyl sulfide with α‐substituted acroleins proceeded, and the corresponding [2+2] cycloadducts were obtained with high enantioselectivity. In particular, the [2+2] cycloadduct obtained from methacrolein is a synthetically useful optically active cyclobutane, which could be transformed to a key intermediate for (+)‐frontalin, a pheromone of Asian elephants.
Direct C−H Arylation Meets Perovskite Solar Cells: Tin‐Free Synthesis Shortcut to High‐Performance Hole‐Transporting Materials
Authors: Chang Yu‐Chieh , Lee Kun‐Mu , Lai Chia‐Hsin , Liu Ching‐Yuan
Published: March 2018

In contrast to the traditional multistep synthesis, we demonstrate herein a two‐step synthesis shortcut to triphenylamine‐based hole‐transporting materials (HTMs) through sequential direct C−H arylations. These hole‐transporting molecules are fabricated in perovskite‐based solar cells (PSCs) that exhibit promising efficiencies up to 17.69 %, which is comparable to PSCs utilizing commercially available 2,2′,7,7′‐tetrakis[N,N‐di(4‐methoxyphenyl)amino]‐9,9′‐spirobifluorene (spiro‐OMeTAD) as the HTM. This is the first report describing the use of step‐saving C−H activations/arylations in the facile synthesis of small‐molecule HTMs for perovskite solar cells.
Click‐evoked auditory brainstem responses and autism spectrum disorder: A meta‐analytic review
Authors: Talge Nicole M. , Tudor Brooke M. , Kileny Paul R.
Published: March 2018

Behavior does not differentiate ASD risk prior to 12 months of age, but biomarkers may inform risk before symptoms emerge. Click‐evoked auditory brainstem responses (ABRs) may be worth consideration due to their measurement properties (noninvasiveness; reliability) and conceptual features (well‐characterized neural generators), but participant characteristics and assessment protocols vary considerably across studies. Our goal is to perform a meta‐analysis of the association between ABRs and ASD. Following an electronic database search (PubMed, Medline, PsycInfo, PsycArticles), we included papers that were written in English, included ASD and typically‐developing (TD) groups, and reported the information needed to calculate standardized mean differences (Hedges's g) for at least one ABR latency component (I, III, V, I‐III, III‐V, I‐V). We weighted and averaged effect sizes across conditions and subsets of participants to yield one estimate per component per study. We then performed random‐effects regressions to generate component‐specific estimates. ASD was associated with longer ABR latencies for Waves III (g = 0.5, 95% CI 0.1, 0.9), V (g = 0.7, 95% CI 0.3, 1.1), I‐III (g = 0.7, 95% CI 0.2, 1.2), and I‐V (g = 0.6, 95% CI 0.2, 1.0). All components showed significant heterogeneity. Associations were strongest among participants ≤8 years of age and those without middle ear abnormalities or elevated auditory thresholds. In sum, associations between ABRs and ASD are medium‐to‐large in size, but exhibit heterogeneity. Identifying sources of heterogeneity is challenging, however, due to power limitations and co‐occurrence of sample/design characteristics across studies. Research addressing the above limitations is crucial to determining the etiologic and/or prognostic value of ABRs for ASD. Autism Res 2018, 11: 916–927. © 2018 International Society for Autism Research, Wiley Periodicals, Inc.

Lay Summary

Auditory brainstem responses (ABR) may be associated with ASD, but participant characteristics and assessment protocols vary considerably across individual studies. Our goal is to combine the results across these studies to facilitate clarity on the topic. Doing so represents a first step in evaluating whether ABRs yield potential for informing the etiology of ASD risk and/or ASD symptom profiles.