bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractRises 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.
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

AbstractTelomeres 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.ObjectivesHere, 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 methodsTL were measured using qPCR from DNA from blood samples from 40 captive chimpanzees and 144 humans.ResultsAnalyses 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.DiscussionThese 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.
The Structural Basis of Transcription: 10 Years After the Nobel Prize in Chemistry
Authors: Hantsche Merle , Cramer Patrick 
Published: October 2016

AbstractTranscription 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

ABSTRACTA 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

ABSTRACTPolypropylene (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

ABSTRACTIn 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

AbstractBoron 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

AbstractThis 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

AbstractHochfeste 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

AbstractDie 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.
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

AbstractWe 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

AbstractWhen 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

AbstractType 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

AbstractAccurate 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

AbstractWe 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

ABSTRACTL‐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.