bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gelation performance of poly(ethylene imine) crosslinking polymer–layered silicate nanocomposite gel system for potential water‐shutoff use in high‐temperature reservoirs
Authors: Pu Wan‐Fen , Yang Yang , Yuan Cheng‐Dong 
Published: August 2016

ABSTRACTPolymer gels have been widely used for water shutoff in mature oil fields. In this paper, polyacrylamide (PAM)–montmorillonite (MMT) nanocomposites (NC) were prepared through in situ intercalative polymerization. Fourier transform infrared spectroscopy and X‐ray diffraction were conducted to characterize the prepared PAM/MMT nanocomposites. The gelation performance of poly(ethylene imine) (PEI) crosslinking PAM/MMT nanocomposite gel system (NC/PEI gel system) was systematically investigated by bottle testing and viscosity measurement methods. The results showed that the gelation performance of the NC/PEI gel system was greatly affected by the total dissolved solids, PAM/MMT nanocomposite concentration, and PEI concentration. The NC/PEI gel system exhibited much better thermal stability and gelation performance than the PAM/PEI gel system at the same conditions. The gelation performance after flowing through porous media of the NC/PEI gel system before injection and that of the subsequently injected gel system was different. The gel strength decreased and the gelation time was delayed after the gel system before injection was flowed through porous media. However, the gel strength of the subsequently injected gel system did not decrease, and only the gelation time was delayed after flowing through porous media. This study suggests that the NC/PEI gel system can be used as a potential water‐shutoff agent in high‐temperature reservoirs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44243.
Controlling micro‐ and nanofibrillar morphology of polymer blends in low‐speed melt spinning process. Part II: Influences of extrusion rate on morphological changes of a PLA/PVA blend through a capillary die
Authors: Tran Nguyen Hoai An , Brünig Harald , Auf der Landwehr Maria , Vogel Roland , Pionteck Jürgen , Heinrich Gert 
Published: August 2016

ABSTRACTThe effects of the extrusion rate on the morphological changes of poly(lactic acid) (PLA)/poly(vinyl alcohol) (PVA) blend through a capillary die were investigated. In this study, the extrusion rate or mass flow rate is altered from 0.5 g min−1 to 2 g min−1 with an increment of 0.5 g min−1. The PLA/PVA blend with a composition of 30/70 (wt %) exhibits a particle matrix morphology with dispersed PLA droplets within the PVA matrix. It is found that, the spherical or ellipsoidal dispersed PLA droplets are elongated and coalesced into rod‐like or longer ellipsoidal droplets when they pass through the capillary die. When the extrusion rate increases, the coalescence between the large PLA droplets occurs more intense. However, the changes of the extrusion rate have no strong effect on the coalescence of small droplets having diameter less than about 150 nm. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44257.
Fiber Arrangement in the Rat Tympanic Membrane
Authors: Liu Jian , Agrawal Sumit K. , Ladak Hanif M. , Wan Wankei 
Published: August 2016

ABSTRACTThe fiber arrangement in the pars tensa of the rat tympanic membrane (TM) was observed using a high resolution scanning electron microscope. The entire pars tensa is composed of fibrils with diameter of approximately 25 nm. These fibrils can be grouped into radial, circular, parabolic, and oblique fibers as reported in other mammals. The radial fibrils interweave into a planar form rather than into discrete cylindrical fibers. Before attaching to the manubrium and tympanic ring, the radial fibrils bend and cross neighboring fibrils to form a random fibril network, and change their direction from perpendicular to somewhat parallel to the manubrium and tympanic ring. The circular fibrils form cylindrical fibers near the peripheral part of the TM while closer to the manubrium, they form planar bundles. The observed fiber morphology and arrangement may provide helpful information in improving numerical models for the TM's acoustical response and designing a fibrous graft for the repair of TM perforations. Anat Rec, 299:1531–1539, 2016. © 2016 Wiley Periodicals, Inc.
Adapting viral safety assurance strategies to continuous processing of biological products
Authors: Johnson Sarah A. , Brown Matthew R. , Lute Scott C. , Brorson Kurt A. 
Published: August 2016

ABSTRACTThere has been a recent drive in commercial large‐scale production of biotechnology products to convert current batch mode processing to continuous processing manufacturing. There have been reports of model systems capable of adapting and linking upstream and downstream technologies into a continuous manufacturing pipeline. However, in many of these proposed continuous processing model systems, viral safety has not been comprehensively addressed. Viral safety and detection is a highly important and often expensive regulatory requirement for any new biological product. To ensure success in the adaption of continuous processing to large‐scale production, there is a need to consider the development of approaches that allow for seamless incorporation of viral testing and clearance/inactivation methods. In this review, we outline potential strategies to apply current viral testing and clearance/inactivation technologies to continuous processing, as well as modifications of existing unit operations to ensure the successful integration of viral clearance into the continuous processing of biological products. Biotechnol. Bioeng. 2017;114: 21–32. © 2016 Wiley Periodicals, Inc.
Modulation of human mesenchymal and pluripotent stem cell behavior using biophysical and biochemical cues: A review
Authors: Ding Sheryl , Kingshott Peter , Thissen Helmut , Pera Martin , Wang Peng‐Yuan 
Published: August 2016

ABSTRACTIn vitro manipulation of human stem cells is a critical process in regenerative medicine and cellular therapies. Strategies and methods to maintain stem cells and direct them into specific lineages are ongoing challenges in these fields. To date, a number of studies have reported that besides biochemical stimulation, biophysical cues in the form of surface patterning and external stimulation also influence stem cell attachment, proliferation, and differentiation, and can be used in cell reprogramming and the maintenance of pluripotency. While biochemical cues are generally effective and easy to deliver, biophysical cues have many other advantages for scalability as they are cost efficient, have a longer lifetime, and can be easily defined. However, different protocols and cell sources utilized in a variety of studies have led to difficulties in obtaining clear conclusions about the effects of the biophysical environment on stem cells. In addition, the examination of different types of external stimulation is time consuming and limited by available fabrication techniques, resulting in a delay in commercialization and clinical applications. In this review, we aim to summarize the most important biophysical cues and methods for the culture of human stem cells, including mesenchymal and pluripotent stem cells, to facilitate their adoption in stem cell biology. The standard classical protocols of using biochemical cues will also be discussed for comparison. We believe that combining biochemical and biophysical stimulation has the greatest potential to generate functionally mature cells at a scalable and inexpensive rate for diverse applications in regenerative medicine and cell therapy. Biotechnol. Bioeng. 2017;114: 260–280. © 2016 Wiley Periodicals, Inc.
Efficient gene knockdown in Clostridium acetobutylicum by synthetic small regulatory RNAs
Authors: Cho Changhee , Lee Sang Yup 
Published: August 2016

ABSTRACTClostridium is considered a promising microbial host for the production of valuable industrial chemicals. However, Clostridium is notorious for the difficulty of genetic manipulations, and consequently metabolic engineering. Thus, much effort has been exerted to develop novel tools for genetic and metabolic engineering of Clostridium strains. Here, we report the development of a synthetic small regulatory RNA (sRNA)‐based system for controlled gene expression in Clostridium acetobutylicum, consisting of a target recognition site, MicC sRNA scaffold, and an RNA chaperone Hfq. To examine the functional operation of sRNA system in C. acetobutylicum, expression control was first examined with the Evoglow fluorescent protein as a model protein. Initially, a C. acetobutylicum protein annotated as Hfq was combined with the synthetic sRNA based on the Escherichia coli MicC scaffold to knockdown Evoglow expression. However, C. acetobutylicum Hfq did not bind to E. coli MicC, while MicC scaffold‐based synthetic sRNA itself was able to knockdown the expression of Evoglow. When E. coli hfq gene was introduced, the knockdown efficiency assessed by measuring fluorescence intensity, could be much enhanced. Then, this E. coli MicC scaffold‐Hfq system was used to knock down adhE1 gene expression in C. acetobutylicum. Knocking down the adhE1 gene expression using the synthetic sRNA led to a 40% decrease in butanol production (2.5 g/L), compared to that (4.5 g/L) produced by the wild‐type strain harboring an empty vector. The sRNA system was further extended to knock down the pta gene expression in the buk mutant C. acetobutylicum strain PJC4BK for enhanced butanol production. The PJC4BK (pPta‐HfqEco) strain, which has the pta gene expression knocked down, was able to produce 16.9 g/L of butanol, which is higher than that (14.9 g/L) produced by the PJC4BK strain, mainly due to reduced acetic acid production. Fed‐batch culture of PJC4BK (pPta‐HfqEco) strain coupled with in situ gas stripping produced 105.5 g of total solvents (70.7 g butanol, 20.5 g acetone, and 14.3 g ethanol), demonstrating that the sRNA‐based engineered C. acetobutylicum strain can be cultured without instability. The synthetic sRNA system reported in this study will be useful for more efficient development of engineered C. acetobutylicum strains capable of producing valuable chemicals and fuels. Biotechnol. Bioeng. 2017;114: 374–383. © 2016 Wiley Periodicals, Inc.
Der Dornfinger – Deutschlands giftigste Spinne
Authors: Petrischak Hannes 
Published: August 2016

AbstractEs gibt nur wenige Spinnenarten in Mitteleuropa, die in der Lage sind, mit ihren Cheliceren die menschliche Haut zu durchdringen. Ein Biss des Ammen‐Dornfingers (Cheiracanthium punctorium) kann durchaus unangenehme Folgen haben. Panik ist jedoch unangebracht, da Bisse selten und nicht wirklich gefährlich sind und sich bei umsichtigem Umgang mit den Tieren in der Regel vermeiden lassen.
Das Schaf: wolliges Herdentier mit Potenzial
Authors: Eitner Pascal 
Published: August 2016

AbstractDie meisten Menschen verbinden Schafe (Ovis gmelini ssp. aries) zuerst mit ihrem flauschigen Äußeren: Schaf = Wolle. Dabei haben wir den Schafen noch viel mehr zu verdanken als nachwachsende Textilrohstoffe. Sie liefern uns wertvolles Leder und hochwertige Lebensmittel wie Fleisch und Milch. Außerdem halten sie Kulturlandschaften durch unermüdliche Beweidung offen, sodass dort eine einzigartige Tier‐ und Pflanzenwelt zu finden ist. Auch die Biotechnologie nutzt die genügsamen Wiederkäuer für moderne Produktionsverfahren.
Characterization of the Aminotransferase ThdN from Thienodolin Biosynthesis in Streptomyces albogriseolus
Authors: Milbredt Daniela , Patallo Eugenio P. , van Pée Karl‐Heinz 
Published: August 2016

AbstractIn Streptomyces albogriseolus the indolethiophen alkaloid thienodolin is derived from tryptophan. The first step in thienodolin biosynthesis is the regioselective chlorination of tryptophan in the 6‐position of the indole ring. The second step is catalyzed by the aminotransferase ThdN. ThdN shows sequence homology (up to 69 % similarity) with known pyridoxal 5′‐phosphate‐dependent aminotransferases of the aspartate aminotransferase family from Gram‐positive bacteria. thdN was heterologously expressed in Pseudomonas fluorescens, and the enzyme was purified by nickel‐affinity chromatography. ThdN is a homodimeric enzyme with a mass of 90 600 kDa and catalyzes the conversion of l‐tryptophan and a number of chlorinated and brominated l‐tryptophans. The lowest KM values were found for 6‐bromo‐ and 6‐chlorotryptophan (40 and 66 μm, respectively). For l‐tryptophan it was 454 μm, which explains why thienodolin is the major product and dechlorothienodolin is only a minor component. The turnover number (kcat) for 7‐chlorotryptophan (128 min−1) was higher than that for the natural substrate 6‐chlorotryptophan (88 min−1).
Percutanous management of tricuspid regurgitation: The “Achilles tendon” of transcatheter valve interventions
Authors: Cilingiroglu Mehmet , Marmagkiolis Konstantinos 
Published: August 2016

Key Points

Moderate‐to‐severe tricuspid insufficiency affects 1.6 million patients in the USA, resulting in increased morbidity and mortality and without safe and effective medical or surgical treatment options.
The unique tricuspid valve anatomy, the presence of immediate adjacent anatomic landmarks at risk and the decreased blood pressure of flow complicate the development of effective transcatheter strategies.
The HOVER trial will assess the safety and effectiveness of the CAVI approach with implantation of the Edwards, Sapien XT in the inferior vena cava.
Contrast‐induced nephropathy and peripheral intervention: Who's keeping track?
Authors: Lipinski Michael J. , Satler Lowell F. 
Published: August 2016

Key Points

The incidence of contrast‐induced nephropathy is high at approximately 10% following peripheral angiography and intervention.
The same measures taken to protect against contrast‐induced nephropathy and acute kidney injury for coronary angiography and intervention should be applied for peripheral angiography and intervention.
Greater or mandatory reporting to the Peripheral Vascular Intervention (PVI) Registry of the NCDR may not only better ascertain the true incidence of CIN in general practice, but to also provide benchmarks for institutions to improve patient outcomes.
Boron‐Boron One‐Electron Sigma Bonds versus B‐X‐B Bridged Structures
Authors: Kusevska Elena , Montero‐Campillo M. Merced , Mó Otilia , Yáñez Manuel 
Published: August 2016

AbstractThe existence of one‐electron B−B σ bonds, for two different sets of compounds, was investigated by analyzing their electron density with different tools, namely QTAIM, ELF, NCIPLOT, and NBO approaches. Our results indicate that although the generic label “one‐electron sigma bond” is often used in the literature, the nature of these bonds varies considerably, or they even do not exist. The [B2X6]−radical anions give place to true covalent one‐electron σ bonds, the stronger the more electronegative is the X substituent. When both boron atoms are substituents in a rigid aromatic moiety, such as naphthalene, to yield 1,8‐disubstituted derivatives, two kinds of equilibrium structures are found, those also stabilized through a one‐electron σ bond (X=OH, F, Cl, CN) and those stabilized by the formation of B‐X‐B bridges (X=H, OMe). These 1,8‐BX2naphthalene derivatives can be considered as analogues of 1,8‐NX2naphthalene proton sponges. While the latter are able to stabilize a proton between the two basic sites, the former are able to stabilize an electron between the two electron‐deficient B atoms. Interestingly, when all the H atoms attached to B are substituted by phenyl groups no one‐electron σ bonds B−B bonds are formed, due to the dispersion of the unpaired electron in the aromatic substituents.
Anions as Triggers in Controlled Release Protocols from Mesoporous Silica Nanoparticles Functionalized with Macrocyclic Copper(II) Complexes
Authors: El Sayed Sameh , Milani Michele , Milanese Chiara , Licchelli Maurizio , Martínez‐Máñez Ramón , Sancenón Félix 
Published: August 2016

AbstractThree different mesoporous silica nano‐sized materials (SC1, SC2, and SC3), loaded with [Ru(bipy)3]2+ dye (bipy=bipyridine) and functionalized on the external surface with three macrocyclic copper(II) complexes (C1, C2, and C3), were synthesized and characterized. When SC1, SC2, and SC3 were suspended in water, the entrapped [Ru(bipy)3]2+ dye was free to diffuse from the inner pores to the solution. However, addition of anions induced certain degrees of pore blockage, with subsequent dye release inhibition. Small monovalent and divalent anions were unable to induce complete pore blockage, whereas bulky and highly charged anions induced marked reductions in [Ru(bipy)3]2+ delivery. The best [Ru(bipy)3]2+ delivery inhibitors were ATP and hexametaphosphate anions. Inhibition was ascribed to the interaction of the anions with the grafted CuII complexes on the surface of the SC1, SC2, and SC3 supports. The hexametaphosphate anion was selected to prepare two capped materials (SC1‐mPh and SC3‐mPh). Studies of the [Ru(bipy)3]2+ dye release from solids SC1‐mPh and SC3‐mPh alone and in the presence of a collection of selected anions (HS−, F−, Br−, Cl−, I−, CN−, HPO42−, AcO−, citrate, NO32−, HCO3−, SO42−, and S2O82−), amino acids (alanine and histidine), thiol‐containing biomolecules (cysteine, methylcysteine, homocysteine, and glutathione (GSH)), and oxidants (H2O2) were performed. None of the chemicals tested, except hydrogen sulphide, was able to induce remarkable cargo delivery in both solids. The observed dye release was ascribed to a demetalation reaction of the C1 and C3 complexes induced by the hydrogen sulphide anion.
Construction of Alkynylplatinum(II) Bzimpy‐Functionalized Metallacycles and Their Hierarchical Self‐Assembly Behavior in Solution Promoted by Pt⋅⋅⋅Pt and π–π Interactions
Authors: Jiang Bo , Zhang Jing , Zheng Wei , Chen Li‐Jun , Yin Guang‐Qiang , Wang Yu‐Xuan , Sun Bin , Li Xiaopeng , Yang Hai‐Bo 
Published: August 2016

AbstractA family of new alkynylplatinum(II) 2,6‐bis(benzimidazol‐2′‐yl)pyridine (bzimpy)‐functionalized supramolecular metallacycles with different shapes and sizes have been successfully prepared by coordination‐driven self‐assembly. The obtained metallacycles showed switchable emission and a strong tendency to form intermolecular Pt⋅⋅⋅Pt and π–π stacking interactions in solution that were not displayed by their individual precursors. Further investigation revealed that the existence of the metallacyclic scaffold at the core could facilitate the formation of intermolecular Pt⋅⋅⋅Pt and π–π stacking interactions of peripheral alkynylplatinum(II) bzimpy units. Moreover, the shapes and sizes of the metallacyclic scaffold have a significant influence on the hierarchical self‐assembly behavior. Among the three metallacycles, hexagonal metallacycle A, with a relatively small size, could spontaneously self‐assemble into an aromatic guest stimuli‐responsive metallogel at room temperature without a heating–cooling process.
Localized Mixed‐Valence and Redox Activity within a Triazole‐Bridged Dinucleating Ligand upon Coordination to Palladium
Authors: Broere Daniël L. J. , Plessius Raoul , Tory Joanne , Demeshko Serhiy , de Bruin Bas , Siegler Maxime A. , Hartl Frantisek , van der Vlugt Jarl Ivar 
Published: August 2016

AbstractThe new dinucleating redox‐active ligand (LH4), bearing two redox‐active NNO‐binding pockets linked by a 1,2,3‐triazole unit, is synthetically readily accessible. Coordination to two equivalents of PdII resulted in the formation of paramagnetic (S=
) dinuclear Pd complexes with a κ2‐N,N′‐bridging triazole and a single bridging chlorido or azido ligand. A combined spectroscopic, spectroelectrochemical, and computational study confirmed Robin–Day Class II mixed‐valence within the redox‐active ligand, with little influence of the secondary bridging anionic ligand. Intervalence charge transfer was observed between the two ligand binding pockets. Selective one‐electron oxidation allowed for isolation of the corresponding cationic ligand‐based diradical species. SQUID (super‐conducting quantum interference device) measurements of these compounds revealed weak anti‐ferromagnetic spin coupling between the two ligand‐centered radicals and an overall singlet ground state in the solid state, which is supported by DFT calculations. The rigid and conjugated dinucleating redox‐active ligand framework thus allows for efficient electronic communication between the two binding pockets.
Photocatalyzed Hydrogen Evolution from Water by a Composite Catalyst of NH2‐MIL‐125(Ti) and Surface Nickel(II) Species
Authors: Meyer Kim , Bashir Shahid , Llorca Jordi , Idriss Hicham , Ranocchiari Marco , van Bokhoven Jeroen A. 
Published: August 2016

AbstractA composite of the metal–organic framework (MOF) NH2‐MIL‐125(Ti) and molecular and ionic nickel(II) species, catalyzed hydrogen evolution from water under UV light. In 95 v/v % aqueous conditions the composite produced hydrogen in quantities two orders of magnitude higher than that of the virgin framework and an order of magnitude greater than that of the molecular catalyst. In a 2 v/v % water and acetonitrile mixture, the composite demonstrated a TOF of 28 mol H2 g(Ni)−1 h−1 and remained active for up to 50 h, sustaining catalysis for three times longer and yielding 20‐fold the amount of hydrogen. Appraisal of physical mixtures of the MOF and each of the nickel species under identical photocatalytic conditions suggest that similar surface localized light sensitization and proton reduction processes operate in the composite catalyst. Both nickel species contribute to catalytic conversion, although different activation behaviors are observed.
Recent Advances in Gold‐Catalyzed Intermolecular Aryl C−H Functionalization
Authors: Kramer Søren 
Published: August 2016

AbstractThe direct and selective functionalization of C−H bonds offers a powerful opportunity for greener and shorter routes to valuable chemicals. While still in its infancy, research exploiting the unique features of gold catalysis for the functionalization of aryl C−H bonds has demonstrated great potential for facile regioselective decoration of (hetero)arenes. Particularly within the last five years, a more general strategy for utilizing oxidative gold catalysis has emanated including an improved understanding of the underlying mechanistic pathways. To encourage and facilitate further research in intermolecular C−H functionalization of arenes with homogeneous gold catalysis, this Minireview critically presents the transformations and mechanistic data available within this field.
One‐Step SnO2 Nanotree Growth
Authors: Schönherr Piet , Hesjedal Thorsten 
Published: August 2016

AbstractA comparison between Au, TiO2 and self‐catalysed growth of SnO2 nanostructures using chemical vapour deposition is reported. TiO2 enables growth of a nanonetwork of SnO2, whereas self‐catalysed growth results in nanoclusters. Using Au catalyst, single‐crystalline SnO2 nanowire trees can be grown in a one‐step process. Two types of trees are identified that differ in size, presence of a catalytic tip, and degree of branching. The growth mechanism of these nanotrees is based on branch‐splitting and self‐seeding by the catalytic tip, facilitating at least three levels of branching, namely trunk, branch and leaf.