bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental modeling of pressurized subglacial water flow: Implications for tunnel valley formation
Authors: Lelandais Thomas , Mourgues Régis , Ravier Édouard , Pochat Stéphane , Strzerzynski Pierre , Bourgeois Olivier
Published: October 2016

Tunnel valleys are elongated hollows commonly found in formerly glaciated areas and interpreted as resulting from subglacial meltwater erosion beneath ice sheets. Over the past two decades, the number of studies of terrestrial tunnel valleys has continuously increased, and their existence has been hypothesized also on Mars, but their formation mechanisms remain poorly understood. We introduce here an innovative experimental approach to examine erosion by circulation of pressurized meltwater within the substratum and at the ice/substratum interface. We used a permeable substratum (sand) partially covered by a viscous, impermeable, and transparent cap (silicon putty), below which we applied a central injection of pure water. Low water pressures led to groundwater circulation in the substratum only, while water pressures exceeding a threshold that is larger than the sum of the glaciostatic and lithostatic pressures led to additional water circulation and formation of drainage landforms at the cap/substratum interface. The formation of these drainage landforms was monitored through time, and their shapes were analyzed from digital elevation models obtained by stereo‐photogrammetry. The experimental landforms include valleys that are similar to natural tunnel valleys in their spatial organization and in a number of diagnostic morphological criteria, such as undulating longitudinal profiles and “tunnel” shapes. These results are consistent with the hypothesis that overpressurized subglacial water circulation controls the formation of tunnel valleys.
Climatic sensitivity, water‐use efficiency, and growth decline in boreal jack pine (Pinus banksiana) forests in Northern Ontario
Authors: Dietrich Rachel , Bell F. Wayne , Silva Lucas C. R. , Cecile Alice , Horwath William R. , Anand Madhur
Published: October 2016

Rises in atmospheric carbon dioxide (atmCO2) levels are known to stimulate photosynthesis and increase intrinsic water‐use efficiency (iWUE) in trees. Stand‐level increases in iWUE depend on the physiological response of dominant species to increases in atmCO2, while tree‐level response to increasing atmCO2 depends on the balance between the direct effects of atmCO2 on photosynthetic rate and the indirect effects of atmCO2 on drought conditions. The aim of this study was to characterize the response of boreal jack pine (Pinus banksiana) stands in Northern Ontario to changes in atmCO2 and associated climatic change over the past 100 years. The impact of changes in growing season length, temperature, and precipitation, as well as atmCO2 on tree growth, was determined using stable carbon isotopes and dendrochronological analysis. Jack pine stands in this study were shown to be in progressive decline. As expected, iWUE was found to increase in association with rising atmCO2. However, increases in iWUE were not directly coupled with atmCO2, suggesting that the degree of iWUE improvement is limited by alternative factors. Water‐use efficiency was negatively associated with tree growth, suggesting that warming‐ and drought‐induced stomatal closure has likely led to deviations from expected atmCO2‐enhanced growth. This finding corroborates that boreal forest stands are likely to face continued stress under future climatic warming.
Engineered Basement Membranes for Regenerating the Corneal Endothelium
Authors: Palchesko Rachelle N. , Funderburgh James L. , Feinberg Adam W.
Published: October 2016

Basement membranes are protein‐rich extracellular matrices (ECM) that are essential for epithelial and endothelial tissue structure and function. Aging and disease cause changes in the physical properties and ECM composition of basement membranes, which has spurred research to develop methods to repair and/or regenerate these tissues. An area of critical clinical need is the cornea, where failure of the endothelium leads to stromal edema and vision loss. Here, an engineered basement membrane (EBM) is developed that consists of a dense layer of collagen IV and/or laminin ≈5–10 nm thick, created using surface‐initiated assembly, conformally attached to a collagen I film. These EBMs are used to engineer a corneal endothelium (CE) that mimics the structure of Descemet's membrane with a thin stromal layer, toward use as a graft for lamellar keratoplasty. Results show that bovine and human CE cells form confluent monolayers on the EBM, express ZO‐1 at the cell–cell borders, and achieve a density of ≈1600 cells mm−2 for 28 and 14 d, respectively. These results demonstrate that the technique is capable of fabricating EBMs with structural and compositional properties that mimic native basement membranes and that EBM may be a suitable carrier for engineering transplant quality CE grafts.
Targeted Dual pH‐Sensitive Lipid ECO/siRNA Self‐Assembly Nanoparticles Facilitate In Vivo Cytosolic sieIF4E Delivery and Overcome Paclitaxel Resistance in Breast Cancer Therapy
Authors: Gujrati Maneesh , Vaidya Amita M. , Mack Margaret , Snyder Dayton , Malamas Anthony , Lu Zheng‐Rong
Published: October 2016

RNAi‐mediated knockdown of oncogenes associated with drug resistance can potentially enhance the efficacy of chemotherapy. Here, we have designed and developed targeted dual pH‐sensitive lipid‐siRNA self‐assembly nanoparticles, RGD‐PEG(HZ)‐ECO/siRNA, which can efficiently silence the oncogene, eukaryotic translation initiation factor 4E (eIF4E), and consequently resensitize triple‐negative breast tumors to paclitaxel. The dual pH‐sensitive function of these nanoparticles facilitates effective cytosolic siRNA delivery in cancer cells, both in vitro and in vivo. Intravenous injection of RGD‐PEG(HZ)‐ECO/siRNA nanoparticles (1.0 mg‐siRNA/kg) results in effective gene silencing for at least one week in MDA‐MB‐231 tumors. In addition, treatment of athymic nude mice with RGD‐PEG(HZ)‐ECO/sieIF4E every 6 days for 6 weeks down‐regulates the overexpression of eIF4E and resensitizes paclitaxel‐resistant MDA‐MB‐231 tumors to paclitaxel, resulting in significant tumor regression at a low dose, with negligible side effects. Moreover, repeated injections of the RGD‐PEG(HZ)‐ECO/siRNA nanoparticles in immunocompetent mice result in minimal immunogenicity, demonstrating their safety and low toxicity. These multifunctional lipid/siRNA nanoparticles constitute a versatile platform of delivery of therapeutic siRNA for treating cancer and other human diseases.
Design Criteria for Ultrathin Single‐Layer Flash Memristors from an Organic Polyradical
Authors: Ezugwu Sabastine , Paquette Joseph A. , Yadav Vishal , Gilroy Joe B. , Fanchini Giovanni
Published: October 2016

The quest for memory devices with “flash” properties, suitable to retain information without any external power source but capable of satisfying the thinness requirements of next‐generation electronics, demands the development of device architectures with a homogeneous layer of active material that can be made as thin as possible. Here, an ultrathin memory device is presented in which the active layer is formed by a 10‐nm homogeneous film of poly‐[1,5‐diisopropyl‐3‐(cis‐5‐norbornene‐exo‐2,3‐dicarboxiimide) 6‐oxoverdazyl] (P6OV) a polyradical with three tunable charge states per radical monomer: positive, neutral, and negative. To the best of our knowledge, these are the thinnest organic flash memristors obtained to date. Careful engineering of the anode and cathode work functions, specifically aligning them with the negative and positive energy levels of the polyradical, is vital to maximize the on/off current ratio and ensure flash operation. Conversely, devices in which the cathode work function aligns with the neutral energy level of P6OV are writable only once. The bistability of this memristors is assigned to two distinct transport regimes in organic polyradicals: extended states and Poole–Frenkel.
Overcoming Charge Collection Limitation at Solid/Liquid Interface by a Controllable Crystal Deficient Overlayer
Authors: Zhang Kan , Ravishankar Sandheep , Ma Ming , Veerappan Ganapathy , Bisquert Juan , Fabregat‐Santiago Francisco , Park Jong Hyeok
Published: October 2016

Bulk and surface charge recombination of photoelectrode are two key processes that significantly hinder solar‐to‐fuel conversion of photoelectrochemical cell (PEC). In this study, the function of a “crystal‐deficient” overlayer is unveiled, which outperforms a traditionally used amorphous or crystalline overlayer in PEC water splitting by exhibiting a high conductivity and large electron diffusion length to enable unlimited electron collection. The optimized ≈2.5 nm thickness of the “crystal‐deficient” shell results in a depletion layer with a width of 3 nm, which overcomes the flat band limitation of the photovoltage and increases the light absorptivity in the wavelength range from 300 to 420 nm. In addition, a 50‐fold increase in the conductivity yields a one‐order‐of‐magnitude increase in the diffusion length of an electron (Ln)(≈20 μm), allowing for unlimited electron collection in the 1.9 μm TiO2 nanowire array with the “crystal‐deficient” shell. The controllable “crystal‐deficient” overlayer in rutile TiO2 nanowires photoanode achieves a photocurrent density greater than 2.0 mA cm−2 at 1.23 V versus reversible hydrogen electrode (RHE), a 1.18% applied bias photon‐to‐current efficiency at 0.49 V versus RHE, a faradaic efficiency greater than 93.5% at 0.6 V versus Pt under air mass 1.5G simulated solar light illumination (100 mW cm−2).
Pseudocapacitive Charge Storage in Thick Composite MoS2 Nanocrystal‐Based Electrodes
Authors: Cook John B. , Kim Hyung‐Seok , Lin Terri C. , Lai Chun‐Han , Dunn Bruce , Tolbert Sarah H.
Published: October 2016

A synthesis methodology is demonstrated to produce MoS2 nanoparticles with an expanded atomic lamellar structure that are ideal for Faradaic‐based capacitive charge storage. While much of the work on MoS2 focuses on the high capacity conversion reaction, that process is prone to poor reversibility. The pseudocapacitive intercalation‐based charge storage reaction of MoS2 is investigated, which is extremely fast and highly reversible. A major challenge in the field of pseudocapacitive‐based energy storage is the development of thick electrodes from nanostructured materials that can sustain the fast inherent kinetics of the active nanocrystalline material. Here a composite electrode comprised of a poly(acrylic acid) binder, carbon fibers, and carbon black additives is utilized. These electrodes deliver a specific capacity of 90 mAh g−1 in less than 20 s and can be cycled 3000 times while retaining over 80% of the original capacity. Quantitative kinetic analysis indicates that over 80% of the charge storage in these MoS2 nanocrystals is pseudocapacitive. Asymmetric full cell devices utilizing a MoS2 nanocrystal‐based electrode and an activated carbon electrode achieve a maximum power density of 5.3 kW kg−1 (with 6 Wh kg−1 energy density) and a maximum energy density of 37 Wh kg−1 (with 74 W kg−1power density).
Exploring Advanced Sandwiched Arrays by Vertical Graphene and N‐Doped Carbon for Enhanced Sodium Storage
Authors: Xie Dong , Xia Xinhui , Zhong Yu , Wang Yadong , Wang Donghuang , Wang Xiuli , Tu Jiangping
Published: October 2016

Smart hybridization of active materials into tailored electrode structure is highly important for developing advanced electrochemical energy storage devices. With the help of sandwiched design, herein a powerful strategy is developed to fabricate three‐layer sandwiched composite core/shell arrays via combined hydrothermal and polymerization approaches. In such a unique architecture, wrinkled MoSe2 nanosheets are sandwiched by vertical graphene (VG) core and N‐doped carbon (N‐C) shell forming sandwiched core/shell arrays. Interesting advantages including high electrical conductivity, strong mechanical stability, and large porosity are combined in the self‐supported VG/MoSe2/N‐C sandwiched arrays. As a preliminary test, the sodium ion storage properties of VG/MoSe2/N‐C sandwiched arrays are characterized and demonstrated with high capacity (540 mA h g−1), enhanced high rate capability, and long‐term cycling stability (298 mA h g−1 at 2.0 A g−1 after 1000 cycles). The sandwiched core/shell structure plays positive roles in the enhancement of electrochemical performances due to dual conductive carbon networks, good volume accommodation, and highly porous structure with fast ion diffusion. The directional electrode design protocol provides a general method for synthesis of high‐performance ternary core/shell electrodes.
Surface wettability effect on fluid transport in nanoscale slit pores
Authors: Zhao Shuangliang , Hu Yaofeng , Yu Xiaochen , Liu Yu , Bai Zhi‐Shan , Liu Honglai
Published: October 2016

The surface wettability effect on fluid transport in nanoscale slit pores is quantitatively accessed by using non‐equilibrium molecular dynamics (NEMD) simulation incorporating with density functional theory (DFT). In particular, the slip lengths of benzene steady flows under various wetting conditions are computed with NEMD simulations and a quasi‐general expression is given, while the structural properties are investigated with DFT. By taking into account the inhomogeneity of fluid density inside pore, we find that the conventional flux enhancement rate is associated with both the molecule slipping and geometrical confinement, and it becomes drastically high in solvophobic pores especially when the pore size is of several fluid diameters. In good agreement with experimental results, we further show that the wettability effect competes with pore size effect in determining the flux after pore inner surface modification, and a high flux can be achieved when the deposited layer is solvophobic yet thin. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1704–1714, 2017
Reaction engineering with enzymes: A relatively uncharted territory
Authors: Puskas Judit E. , Kantor Jozsef , Shrikhande Gayatri
Published: October 2016

This article discusses the history of enzyme kinetics developed by Michaelis and Menten, and recent work extending kinetics for enzyme‐catalyzed reactions in organic solvents. Based on kinetic studies of the transesterification of vinyl methacrylate with 2‐hydroxyethyl acrylate catalyzed by Candida antarctica lipase B, a new model is proposed that resembles the kinetic model of controlled/living polymerizations governed by dynamic equilibrium of active and dormant species. Experimental data indicates that by judicious selection of reaction conditions steady‐state conditions can be achieved and very clean products with quantitative conversion can be produced. © 2016 American Institute of Chemical Engineers AIChE J, 63: 266–272, 2017
An optimization‐based approach for structural design of self‐assembled DNA tiles
Authors: Gao Yu , Mi Yongli , Lakerveld Richard
Published: October 2016

DNA tiles are self‐assembled nanostructures, which offer exciting opportunities for synthesis of novel materials. A challenge for structural design of DNA tiles is to identify optimal locations for so‐called crossovers, which are bridges between DNA double helices formed by pairs of single‐stranded DNA. An optimization‐based approach is presented to identify optimal locations for such crossovers. Minimization of a potential‐energy model for a given structural design demonstrates the importance of local minima. Both deterministic global optimization of a reduced model and multistart optimization of the full model are applied successfully to identify the global minimum. MINLP optimization using a branch‐and‐bound algorithm (GAMS/SBB) identifies an optimal structural design of a DNA tile successfully with significant reduction in computational load compared to exhaustive enumeration, which demonstrates the potential of the proposed method to reduce trial‐and‐error efforts for structural design of DNA tiles. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1804–1817, 2017
Familial Gordon syndrome associated with a PIEZO2 mutation
Authors: Alisch Franz , Weichert Alexander , Kalache Karim , Paradiso Viola , Longardt Ann Carolin , Dame Christof , Hoffmann Katrin , Horn Denise
Published: October 2016

Gordon syndrome or distal arthrogryposis type 3 is a rare autosomal dominant disorder characterized by contractures of upper and lower limbs. It is distinguishable from other forms of distal arthrogryposis by cleft palate and short stature. Recently, Gordon syndrome has been associated to heterozygous mutations in the piezo‐type mechanosensitive ion channel component 2 gene (PIEZO2). Different mutations of this gene also cause distal arthrogryposis type 5 and Marden–Walker syndrome. Dysfunction of this ion channel provides pleiotropic effects on joints, ocular muscles, and bone development. Here, we present a family with three affected individuals exhibiting multiple contractures (metacarpo‐phalangeal and interphalangeal joints as well as elbow, shoulder, knee, and ankle joints), clubfeet, short stature, bifid uvula/cleft palate, and a distinct facial phenotype including ptosis. In addition, mild intellectual disability and delay in psychomotor development are obvious. The multigenerational phenotypic spectrum of Gordon syndrome is present in the 37‐year‐old father, his 4‐year‐old son and a male neonate showing typical signs of arthrogryposis in the prenatal ultrasound examination already seen at 13 week of gestation. In all affected family members, we identified the PIEZO2 mutation c.8057G>A (p.Arg2686His) by Sanger sequencing. Our analysis indicated that mild delay in psychomotor development and intellectual disability could be part of the phenotypic spectrum of Gordon syndrome. © 2016 Wiley Periodicals, Inc.
Paternal and grandpaternal ages at conception and descendant telomere lengths in chimpanzees and humans
Authors: Eisenberg Dan T. A. , Tackney Justin , Cawthon Richard M. , Cloutier Christina Theresa , Hawkes Kristen
Published: October 2016

Telomeres are repeating DNA at chromosome ends. Telomere length (TL) declines with age in most human tissues, and shorter TL is thought to accelerate senescence. In contrast, older men have sperm with longer TL; correspondingly, older paternal age at conception (PAC) predicts longer TL in offspring. This PAC‐effect could be a unique form of transgenerational genetic plasticity that modifies somatic maintenance in response to cues of recent ancestral experience. The PAC‐effect has not been examined in any non‐human mammals.

Objectives

Here, we examine the PAC‐effect in chimpanzees (Pan troglodytes). The PAC‐effect on TL is thought to be driven by continual production of sperm—the same process that drives increased de novo mutations with PAC. As chimpanzees have both greater sperm production and greater sperm mutation rates with PAC than humans, we predict that the PAC‐effect on TL will be more pronounced in chimpanzees. Additionally we examine whether PAC predicts TL of grandchildren.

Materials and methods

TL were measured using qPCR from DNA from blood samples from 40 captive chimpanzees and 144 humans.

Results

Analyses showed increasing TL with PAC in chimpanzees (p = .009) with a slope six times that in humans (p = .026). No associations between TL and grandpaternal ages were found in humans or chimpanzees—although statistical power was low.

Discussion

These results suggest that sperm production rates across species may be a determinant of the PAC‐effect on offspring TL. This raises the possibility that sperm production rates within species may influence the TL passed on to offspring.
‘A Waste of Time’? 2nd Circuit Reconsiders Class Waivers As Mandatory Arbitration Heads to Supreme Court
Authors: Bleemer Russ
Published: October 2016

The end of summer turned out to be the beginning of the final stages of a crucial four‐year‐old argument over the use of arbitration, and the future of the conflict resolution process in U.S. contracts.
The Structural Basis of Transcription: 10 Years After the Nobel Prize in Chemistry
Authors: Hantsche Merle , Cramer Patrick
Published: October 2016

Transcription is the first step in the expression of genetic information in all living cells. The regulation of transcription underlies cell differentiation, organism development, and the responses of living systems to changes in the environment. During transcription, the enzyme RNA polymerase uses DNA as a template to synthesize a complementary RNA copy from a gene. Herein, we summarize the progress in our understanding of the structural basis of eukaryotic gene transcription that has been made in the ten years since the Nobel Prize in Chemistry was given to Roger Kornberg in 2006. The basis for transcription initiation and RNA chain elongation is emerging, but the intricate mechanisms of transcription regulation remain to be elucidated. The field has also developed hybrid methods for structural biology that combine several techniques to determine the three‐dimensional architecture of large and transient macromolecular assemblies.
Half‐sandwich ruthenium, rhodium and iridium complexes featuring oxime ligands: Structural studies and preliminary investigation of in vitro and in vivo anti‐tumour activities
Authors: Palepu Narasinga Rao , Adhikari Sanjay , J Richard Premkumar , Verma Akalesh K. , Shepherd Samantha L. , Phillips Roger M. , Kaminsky Werner , Kollipara Mohan Rao
Published: October 2016

Half‐sandwich ruthenium, rhodium and iridium complexes (1–12) were synthesized with aldoxime (L1), ketoxime (L2) and amidoxime (L3) ligands. Ligands have the general formula [PyC(R)NOH], where R = H (L1), R = CH3 (L2) and R = NH2 (L3). Reaction of [{(arene)MCl2}2] (arene = p‐cymene, benzene, Cp*; M = Ru, Rh, Ir) with ligands L1–L3 in 1:2 metal precursor‐to‐ligand ratio yielded complexes such as [{(arene)MLκ2(N∩N)Cl}]PF6. All the ligands act as bidentate chelating nitrogen donors in κ2(N∩N) fashion while forming complexes. In vitro anti‐tumour activity of complexes 2 and 10 against HT‐29 (human colorectal cancer), BE (human colorectal cancer) and MIA PaCa‐2 (human pancreatic cancer) cell lines and non‐cancer cell line ARPE‐19 (human retinal epithelial cells) revealed a comparable activity although complex 2 demonstrated greater selectivity for MIA PaCa‐2 cells than cisplatin. Further studies demonstrated that complexes 3, 6, 9 and 12 induced significant apoptosis in Dalton's ascites lymphoma (DL) cells. In vivo anti‐tumour activity of complex 2 on DL‐bearing mice revealed a statistically significant anti‐tumour activity (P = 0.0052). Complexes 1–12 exhibit HOMO–LUMO energy gaps from 3.31 to 3.68 eV. Time‐dependent density functional theory calculations explain the nature of electronic transitions and were in good agreement with experiments.
Effect of octa(aminopropyl) polyhedral oligomeric silsesquioxane (OapPOSS) functionalized graphene oxide on the mechanical, thermal, and hydrophobic properties of waterborne polyurethane composites
Authors: Hu Ling , Jiang Pingping , Bian Gang , Huang Min , Haryono Agus , Zhang Pingbo , Bao Yanmin , Xia Jialiang
Published: October 2016

A novel graphene nanomaterial functionalized by octa(aminopropyl) polyhedral oligomeric silsesquioxane (OapPOSS) was synthesized and then confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), Raman spectroscopy, X‐ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy with energy‐dispersive X‐ray spectroscopy (SEM EDX), atomic force microscopy, and X‐ray diffraction. The obtained functionalized graphene (OapPOSS‐GO) was used to reinforce waterborne polyurethane (WPU) to obtain OapPOSS‐GO/WPU nanocomposites by in situ polymerization. The thermal, mechanical, and hydrophobic properties of nanocomposites as well as the dispersion behavior of OapPOSS‐GO in the polymer were investigated by TGA, a tensile testing machine, water contact angle tests, and field emission SEM, respectively. Compared with GO/WPU and OapPOSS/WPU composites, the strong interfacial interaction between OapPOSS‐GO and the WPU matrix facilitates a much better dispersion and load transfer from the WPU matrix to the OapPOSS‐GO. It was found that the tensile strength of the OapPOSS‐GO/WPU composite film with 0.20 wt % OapPOSS‐GO exhibited a 2.5‐fold increase in tensile strength, compared with neat WPU. Better thermal stability and hydrophobicity of nanocomposites were also achieved by the addition of OapPOSS‐GO. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44440.
Processing–morphology–property relationships of polypropylene–graphene nanoplatelets nanocomposites
Authors: Zhang Jingjing , He Suihua , Lv Pengrong , Chen Yuqiang
Published: October 2016

Polypropylene (PP) nanocomposites reinforced with graphene nanoplatelets (GNPs) were prepared via melt extrusion. A special sheet die containing with two shunt plates was designed. The relationships among the flow field of the special die, exfoliation, and dispersion morphology of the GNPs in PP and the macroscopic properties of the nanocomposites were analyzed. Flow field simulation results show that the die with shunt plates provided a high shear stress, high pressure, and high velocity. The differential scanning calorimetry, X‐ray scattering, and electron microscopy results reveal that the nanocomposites prepared by the die with the shunt plates had higher crystallinity values and higher exfoliation degrees of GNPs. The orientation of the GNPs parallel with the extrusion direction was also observed. The nanocomposites prepared by the die with shunt plates showed a higher electrical volume conductivity, thermal conductivity, and tensile properties. This indicated that the high shear stress exfoliated the GNPs effectively to a thinner layer and then enhanced the electrical, thermal, and mechanical properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44486.
The impact of nonpolar coagulation bath‐immiscible liquid additives on the polyethersulfone membranes structure and performance
Authors: Teimoori Mostafa , Hashemifard Seyed Abdollatif , Ismail Ahmad Fauzi , Abbasi Mohsen
Published: October 2016

In this study, the impact of several normal alkanes as additives on the structural parameters and the morphologies of flat sheet PES membranes were investigated. The asymmetric membranes were fabricated by phase inversion method. Also n‐hexane, n‐decane, and n‐tetradecane were used as additives. The effects of different concentrations of these additives were investigated by producing the ternary phase diagrams. Further the membranes were characterized by means of solute transport test, contact angle, pure water flux, porosity measurement, and scanning electronic microscopy. It was expected that two distinct phase inversions to be occurred since both the polymer and the additives were insoluble in the coagulation bath. Observations revealed that n‐hexane and n‐decane were less effective compared with n‐tetradecane in terms of binodal shifting toward PES/NMP axis. In conclusion, it was revealed that the coagulation bath immiscible‐liquid additives had a major impact on the membranes structure in order to achieve the enhanced properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44509.
Negatively Charged π‐Electronic Systems by Deprotonation of Hydroxy‐Substituted Dipyrrolyldiketone Boron Complexes
Authors: Sasano Yoshifumi , Yasuda Nobuhiro , Maeda Hiromitsu
Published: October 2016

Boron complexes of meso‐hydroxy‐substituted dipyrrolyldiketones, as the precursors of negatively charged π‐electronic systems, were synthesized via the oxidative introduction of an acetoxy unit at the meso position of dipyrrolyldiketones and subsequent hydrolysis. The anionic site formed upon deprotonation was moderately stabilized by hydrogen‐bond‐donating pyrrole NH, generating non‐complexing anionic species.
Non‐Fragile Observer‐Based Control for Uncertain Neutral‐Type Systems via Sliding Mode Technique
Authors: Liu Zhen , Gao Cunchen , Xiao Huimin , Kao Yonggui
Published: October 2016

This paper is concerned with the problem of observer‐based
control for a class of uncertain neutral‐type systems subjected to external disturbance by utilizing sliding mode technique. A novel sliding mode control (SMC) strategy is proposed based on the state estimate and the output. A new sufficient condition of robust asymptotic stability with
disturbance attenuation level for the overall systems composed of the original system and error system in the sliding mode is derived in terms of a linear matrix inequality (LMI). Then, a new adaptive controller is designed to guarantee the reachability of the predefined sliding surface in finite‐time. Finally, numerical examples are provided to verify the effectiveness of the proposed method.
Methoden zur Analyse des Bruchverhaltens hochfester Stahlfaserbetone
Authors: Hüsken Götz , Pirskawetz Stephan , Meinel Dietmar , Babski Veronika , Kühne Hans‐Carsten
Published: October 2016

Hochfeste und ultrahochfeste Stahlfaserbetone eignen sich aufgrund ihrer Eigenschaften für den Einsatz bei extremen mechanischen Beanspruchungen. Das für diesen Einsatz erforderliche duktile Bruchverhalten unter Zugbeanspruchung wird ausschließlich durch die Zugabe von geeigneten Stahlfasern und deren Wirkung in der Zementsteinmatrix erreicht. Für eine gezielte stoffliche Optimierung des Systems sind fundierte Kenntnisse zur Wirkungsweise der Stahlfasern notwendig, die bei bisherigen Untersuchungen lediglich auf Basis von klassischen Messverfahren zerstörender Prüfungen gewonnen wurden. Durch das Einbeziehen von Methoden der zerstörungsfreien Materialcharakterisierung können das Bruchverhalten hochfester und ultrahochfester Stahlfaserbetone orts‐ und zeitaufgelöst untersucht und die einzelnen Phasen des Schädigungsprozesses identifiziert werden.

Anhand der vorliegenden Ergebnisse von Zugversuchen eines ultrahochfesten Stahlfaserbetons wird der kombinierte Einsatz von Methoden der zerstörungsfreien Materialprüfung gezeigt und deren Anwendbarkeit in der Analyse des Bruchverhaltens diskutiert. Das Hauptaugenmerk liegt dabei auf der Charakterisierung der ausschlaggebenden Versagensmodi unter Zugbelastung durch die einzelnen Verfahren und dem Vergleich zu klassischen Messmethoden (z. B. Extensometer). Die Zugversuche wurden dazu parallel durch optische Verformungsanalyse mittels Bildkorrelation (DIC), Schallemissionsanalyse (SEA) und 3‐D‐Computertomografie (CT) begleitet.
Messtechnische Überwachung extern vorgespannter Betonbrücken
Authors: Boros Vazul , Novák Balthasar , Pelke Eberhard , Koster Gerhard
Published: October 2016

Die Instandsetzung von bestehenden Massivbrücken durch externe Vorspannung stellt eine verbreitete Maßnahme der Tragwerksertüchtigung dar, da so Defizite in der Tragfähigkeit, Gebrauchstauglichkeit und Dauerhaftigkeit von Bauwerken kompensiert und eine Verlängerung der Nutzungsdauer erreicht werden können. Ein wichtiges Detail solcher Verstärkungsmaßnahmen ist die Endverankerung der externen Spannglieder, da hier beachtliche Kräfte in das Bauwerk eingeleitet werden. An drei mit externer Vorspannung verstärkten Talbrücken in Hessen wurde ein Monitoring installiert. Es wurden Wegaufnehmer in Längs‐ und Querrichtung der Brücke an die Verankerungsblöcke und Dehnungsmessstreifen an die Querspannstäbe installiert, um die Kraftübertragung zu überwachen. Zusätzlich wurde die Luft‐ und Bauwerkstemperatur aufgezeichnet. Über den Beobachtungszeitraum von mehr als drei Jahren konnten sowohl die Auswirkungen der Verstärkung erfasst als auch der Effekt der kurz‐ und langzeitigen Temperaturschwankungen beobachtet werden. Auch die Spannkraftverluste der Spannstäbe wurden verfolgt. Die Messergebnisse wurden kontinuierlich ausgewertet und bei Überschreitung definierter Grenzbedingungen wurde eine automatisierte Warnung ausgelöst. Bei einem der Bauwerke konnte zudem die Überfahrt von Schwertransporten mithilfe der Monitoringeinrichtung überwacht werden. Insgesamt lieferten die Messungen wertvolle Hinweise zum Tragverhalten sowie zur Interaktion zwischen Verstärkung und Bestandsbauwerk.
How does the choice of A‐level subjects vary with students' socio‐economic status in English state schools?
Authors: Dilnot Catherine
Published: October 2016

The reasons why students from lower socio‐economic groups are under‐represented at high status universities are not yet entirely understood, but evidence suggests that part of the gap may be a consequence of differential choice of A‐levels by social background. The Russell Group of universities has since 2011 published guidance on A‐level subject choices, describing some A‐levels as ‘facilitating’ in that choosing these helps keep the largest number of Russell Group degree courses open. The numbers of students gaining AAB in facilitating subjects has subsequently been developed as a performance measure for individual schools and sixth form colleges, and, in aggregate, as a government Social Mobility Indicator. While it is clear that there is a gap between the proportions of students in maintained and private schools achieving this measure, there is little other work to date on how social background is related to the take‐up of facilitating subjects, or to a more fine‐grained categorization of all the large number of ‘non‐facilitating’ subjects. I develop a taxonomy of all 96 A‐levels certified for English students in 2014/15 beyond the facilitating/non‐facilitating dichotomy according to Russell Group members’ expressed preferences, and use it to analyse the A‐level subject choices of three A‐level cohorts (2010–2012), using National Pupil Database data. I find that large differentials in A‐level subject choice exist by social background, particularly for facilitating subjects. These differentials substantially disappear when GCSE attainment and subject choices are taken into account. Closing this choice gap at A‐level is likely therefore to depend on reducing differentials in attainment and subject choice by social background at GCSE. The introduction of the EBacc may help with the GCSE subject choice element.
Luminescent properties of 4‐aminobenzo‐15‐crown‐5 after preferential binding of ferric ions in aqueous solutions
Authors: Ly Nguyễn Hoàng , Yoon Jinha , Nguyen Dinh Bao , Cho Kwang‐Hwi , Joo Sang‐Woo
Published: October 2016

We report a combined approach that introduces the use of 4‐aminobenzo‐15‐crown‐5 (4AB15C5) for the detection of ferric(III) ions by colorimetric, ultraviolet (UV)–visible light absorption, fluorescence, and live‐cell imaging techniques along with density functional theory (DFT) calculations. We have found that 4AB15C5 is sensitive and selective for binding ferric(III) ions in aqueous solutions. DFT calculations using the polarizable continuum model have been used to explain the strong binding of the ferric ion by 4AB15C5 in aqueous solutions. The detection limit in the fluorescence quenching measurements was found to be as low as 50 μM for the ferric ion with a determined Stern–Volmer constant of 1.52 × 104 M−1. Fluorescence intensity did not change for other ions tested, Fe2+, Co2+, Mn2+, Mg2+, Zn2+, Ca2+, NH4+, Na+, and K+ ions. Live‐cell fluorescence imaging was also used to check the intracellular variations in ferric ion levels. Our spectroscopic data indicated that 4AB15C5 can bind ferric ions selectively in aqueous solutions.
Enhanced fluorescence of tetrasulfonated zinc phthalocyanine by graphene quantum dots and its application in molecular sensing/imaging
Authors: Wang Jian , Zhang Yanjun , Ye Jiqing , Jiang Zhou
Published: October 2016

When excited at 435 nm, tetra‐sulfonate zinc phthalocyanine (ZnPcS4) emitted dual fluorescence at 495 and 702 nm. The abnormal fluorescence at 495 nm was experimentally studied and analyzed in detail for the first time. The abnormal fluorescence at 495 nm was deduced to originate from triplet–triplet (T–T) energy transfer of excited phthalocyanine (3*ZnPcS4). Furthermore, graphene quantum dots (GQDs) enhanced the 495 nm fluorescence quantum yield (Q) of ZnPcS4. The fluorescence properties of ZnPcS4–GQDs conjugate were retained in a cellular environment. Based on the fluorescence of ZnPcS4–GQDs conjugate, we designed and prepared an Apt29/thrombin/Apt15 sandwich thrombin sensor with high specificity and affinity. This cost‐saving, simple operational sensing strategy can be extended to use in sensing/imaging of other biomolecules.
Rotation‐based technique for the rapid densification of tubular collagen gel scaffolds
Authors: Loy Caroline , Lainé Audrey , Mantovani Diego
Published: October 2016

Type I collagen gel is often used as a tubular scaffold because of its easy molding properties as well as its biocompatibility, low immunogenicity and ability to be remodelled by cells. However, its highly hydrated structure contributes to its weak mechanical properties and reduces its ability to be handled, which is important in tubular tissue engineering. Although cell‐driven remodelling of collagen matrices is known to reinforce their mechanical properties, this process can take weeks. This study introduces a novel, simple, and rapid technique using a rotational bioreactor to expel water and densify collagen under sterile conditions to generate denser and stronger collagen gel scaffolds. This process produces a dense tubular‐shaped collagen gel which, compared to standard collagen gel scaffolds, shows a decreased wall thickness and a four‐fold increase in collagen concentration. A denser collagen fiber network observed by immunofluorescence staining and mechanical characterisation shows a twenty‐fold increase in the elastic modulus of the dense constructs which maintain cell viability inside the scaffold. Moreover, by simply modifying the scaffold mold, customised shapes and sizes can be obtained to provide a wide range of applications, including complex tubular geometries and multi‐layered scaffolds for the culture of various cell types and tissues.
Case study on human α1‐antitrypsin: Recombinant protein titers obtained by commercial ELISA kits are inaccurate
Authors: Hansen Henning Gram , Kildegaard Helene Faustrup , Lee Gyun Min , Kol Stefan
Published: October 2016

Accurate titer determination of recombinant proteins is crucial for evaluating protein production cell lines and processes. Even though enzyme‐linked immunosorbent assay (ELISA) is the most widely used assay for determining protein titer, little is known about the accuracy of commercially available ELISA kits. We observed that estimations of recombinant human ø1‐antitrypsin (rø1AT) titer by Coomassie‐stained SDS‐PAGE gels did not correspond to previously obtained titers obtained by a commercially available ELISA kit. This prompted us to develop two independent quantification assays based on biolayer interferometry and reversed‐phase high‐performance liquid chromatography. We compared the rø1AT titer obtained by these assays with three different off‐the‐shelf ELISA kits and found that the ELISA kits led to inconsistent results. The data presented here show that recombinant protein titers determined by ELISA kits cannot be trusted per se. Consequently, any ELISA kit to be used for determining recombinant protein titer must be validated by a different, preferably orthogonal method.
DNA‐doxorubicin interaction: New insights and peculiarities
Authors: Silva E. F. , Bazoni R. F. , Ramos E. B. , Rocha M. S.
Published: October 2016

We have investigated the interaction of the DNA molecule with the anticancer drug doxorubicin (doxo) by using three different experimental techniques: single molecule stretching, single molecule imaging, and dynamic light scattering. Such techniques allowed us to get new insights on the mechanical behavior of the DNA‐doxo complexes as well as on the physical chemistry of the interaction. First, the contour length data obtained from single molecule stretching were used to extract the physicochemical parameters of the DNA‐doxo interaction under different buffer conditions. This analysis has proven that the physical chemistry of such interaction can be modulated by changing the ionic strength of the surrounding buffer. In particular we have found that at low ionc strengths doxo interacts with DNA by simple intercalation (no aggregation) and/or by forming bound dimers. For high ionic strengths, otherwise, doxo‐doxo self‐association is enhanced, giving rise to the formation of bound doxo aggregates composed by 3 to 4 molecules along the double‐helix. On the other hand, the results obtained for the persistence length of the DNA‐doxo complexes is strongly force‐dependent, presenting different behaviors when measured with stretching or non‐stretching techniques.
Metabolic engineering of Escherichia coli for microbial production of L‐methionine
Authors: Huang Jian‐Feng , Liu Zhi‐Qiang , Jin Li‐Qun , Tang Xiao‐Ling , Shen Zhen‐Yang , Yin Huan‐Huan , Zheng Yu‐Guo
Published: October 2016

L‐methionine has attracted a great deal of attention for its nutritional, pharmaceutical, and clinical applications. In this study, Escherichia coli W3110 was engineered via deletion of a negative transcriptional regulator MetJ and over‐expression of homoserine O‐succinyltransferase MetA together with efflux transporter YjeH, resulting in L‐methionine overproduction which is up to 413.16 mg/L. The partial inactivation of the L‐methionine import system MetD via disruption of metI made the engineered E. coli ΔmetJ ΔmetI/pTrcA*H more tolerant to high L‐ethionine concentration and accumulated L‐methionine to a level 43.65% higher than that of E. coli W3110 ΔmetJ/pTrcA*H. Furthermore, deletion of lysA, which blocks the lysine biosynthesis pathway, led to a further 8.5‐fold increase in L‐methionine titer of E. coli ΔmetJ ΔmetI ΔlysA/pTrcA*H. Finally, addition of Na2S2O3 to the media led to an increase of fermentation titer of 11.45%. After optimization, constructed E. coli ΔmetJ ΔmetI ΔlysA/pTrcA*H was able to produce 9.75 g/L L‐methionine with productivity of 0.20 g/L/h in a 5 L bioreactor. This novel metabolically tailored strain of E. coli provides an efficient platform for microbial production of L‐methionine. Biotechnol. Bioeng. 2017;114: 843–851. © 2016 Wiley Periodicals, Inc.
A New Rhodamine‐based Fluorescent Probe for the Discrimination of Fe3+ from Fe2+
Authors: You Qi‐Hua , Huang Hua‐Bin , Zhuang Zhi‐Xia , Wang Xiao‐Ru , Chan Wing‐Hong
Published: October 2016

A new rhodamine‐based fluorescent probe for the discrimination of Fe3+ from Fe2+ has been designed and investigated. The probe shows an immediate visual color change in response to Fe3+ and Cu2+, while only Fe3+ triggers the fluorescent change of the probe. The existence of large amount of other metal ions shows negligible interference in the detection of Fe3+. The association constant K
ass of 4.64 × 108 M−2 (R2
= 0.994) and 5.38 × 108 M−2 (R2
= 0.991) of the complex was derived from UV/Vis and fluorescence titration assuming 1:2 stoichiometry of probe–Fe3+ complex, respectively.
Public Figure Attacks in the United States, 1995–2015
Authors: Meloy J. Reid , Amman Molly
Published: October 2016

An archival descriptive study of public figure attackers in the United States between 1995 and 2015 was undertaken. Fifty‐six incidents were identified, primarily through exhaustive internet searches, composed of 58 attackers and 58 victims. A code book was developed which focused upon victims, offenders, pre‐attack behaviors including direct threats, attack characteristics, post‐offense and other outcomes, motivations and psychological abstracts. The average interrater agreement for coding of bivariate variables was 0.835 (intraclass correlation coefficient). The three most likely victim categories were politicians, judges, and athletes. Attackers were males, many with a psychiatric disorder, most were grandiose, and most had both a violent and nonviolent criminal history. The known motivations for the attacks were often angry and personal, the most common being dissatisfaction with a judicial or other governmental process (23%). In only one case was the primary motivation to achieve notoriety. Lethality risk during an attack was 55%. Collateral injury or death occurred in 29% of the incidents. Only 5% communicated a direct threat to the target beforehand. The term “publicly intimate figure” is introduced to describe the sociocultural blurring of public and private lives among the targets, and its possible role in some attackers' perceptions and motivations. Copyright © 2016 John Wiley & Sons, Ltd.
Recent advances in immobilization strategies for glycosidases
Authors: Karav Sercan , Cohen Joshua L. , Barile Daniela , de Moura Bell Juliana Maria Leite Nobrega
Published: October 2016

Glycans play important biological roles in cell‐to‐cell interactions, protection against pathogens, as well as in proper protein folding and stability, and are thus interesting targets for scientists. Although their mechanisms of action have been widely investigated and hypothesized, their biological functions are not well understood due to the lack of deglycosylation methods for large‐scale isolation of these compounds. Isolation of glycans in their native state is crucial for the investigation of their biological functions. However, current enzymatic and chemical deglycosylation techniques require harsh pretreatment and reaction conditions (high temperature and use of detergents) that hinder the isolation of native glycan structures. Indeed, the recent isolation of new endoglycosidases that are able to cleave a wider variety of linkages and efficiently hydrolyze native proteins has opened up the opportunity to elucidate the biological roles of a higher variety of glycans in their native state. As an example, our research group recently isolated a novel Endo‐β‐N‐acetylglucosaminidase from Bifidobacterium longum subsp. infantis ATCC 15697 (EndoBI‐1) that cleaves N‐N′‐diacetyl chitobiose moieties found in the N‐linked glycan (N‐glycan) core of high mannose, hybrid, and complex N‐glycans. This enzyme is also active on native proteins, which enables native glycan isolation, a key advantage when evaluating their biological activities. Efficient, stable, and economically viable enzymatic release of N‐glycans requires the selection of appropriate immobilization strategies. In this review, we discuss the state‐of‐the‐art of various immobilization techniques (physical adsorption, covalent binding, aggregation, and entrapment) for glycosidases, as well as their potential substrates and matrices. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:104–112, 2017