bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzyme‐conjugated nanosensors with tunable detection limits for small biomolecule determination
Authors: Ferris Mark S. , Elms Makayla K. , Cash Kevin J. 
Published: June 2019

AbstractPolymeric nanosensors are more appealing than electrochemical sensors for advanced biological imaging applications, but more development is required before polymeric nanosensors can achieve widespread application. The detection of small biomolecules without a suitable ionophore, such as the detection of glucose, depends on enzymatic recognition by mixing oxidase enzymes with nanosensors. However, conjugation schemes and response control methods are needed to make polymeric nanosensors suitable for real‐world applications. In this work, we develop enzyme‐conjugated nanosensors based on the biotin/avidin interaction with two unique structures. The response of the first structure is controllable through changes to the concentrations of enzyme and avidin as well as surface biotinylation level during synthesis, while the second structure requires a simpler synthesis and has a controllable response through changes to the surface biotinylation level. We also report findings about optimal avidin concentration and separation of unbound enzyme from the enzyme‐nanosensor conjugates through a magnetic purification approach.
Enhanced antipressure ability through graphene oxide membrane by intercalating g‐C3N4 nanosheets for water purification
Authors: Liu Lingfei , Zhou Yisa , Xue Jian , Wang Haihui 
Published: June 2019

AbstractGraphene oxide (GO) membranes have shown great potential for water purification, but their permeability and antipressure ability are poor, which limits their practical applications. In this study, two‐dimensional graphitic carbon nitride (g‐C3N4) nanosheet‐intercalated GO (GOCN) membranes were developed to improve the separation performance of GO membranes, especially under high operating pressure. After incorporation of the g‐C3N4 nanosheets, the amount of permeable nanochannels (wrinkles or corrugation) in the membrane increased; hence, the water permeance was effectively improved (twice as high as that of GO membranes). Moreover, the antipressure performance of the GOCN membranes was significantly enhanced (even below 0.5 MPa pressure) as the nanochannels in the composite membranes become stable and rigid due to the support of the pressure‐resistant g‐C3N4 nanosheets. The good separation performance demonstrates that the intercalation of g‐C3N4 is an effective strategy to improve the GO‐based membrane properties, which can promote their application in water purification.
Understanding primate‐human interaction: Socioeconomic correlates of local awareness and attitude toward the endangered golden langur Trachypithecus geei (Khajuria, 1956) in Bhutan
Authors: Thinley Phuntsho , Rajaratnam Rajanathan , Tighe Matthew , Vernes Karl , Norbu Tshewang , Dorji Rinchen , Tenzin Sangay 
Published: June 2019

AbstractDespite the golden langur's (Trachypithecus geei) endangered and totally protected status, local awareness and attitude toward this species is poorly understood. We investigated local awareness and attitude in Bhutan by interviewing 1,143 households in the districts of Dagana, Sarpang, Trongsa, Tsirang, and Zhemgang, and analyzing data through a conditional inference tree analysis. Most respondents were not aware of the golden langur's nationally protected (53%; n = 604) and globally endangered status (64%; n = 730), but their location of residence (inside/outside a protected area; p < .001) and education level (p < .001) significantly influenced awareness. The majority of respondents (87%; n = 999) liked the golden langur but the attitude was significantly influenced primarily by whether or not they experienced crop damage by golden langurs (p < .001), and subsequently by location of residence (p < .001), local belief (p < .01), gender (p < .05), and personal encounter with a golden langur (p < .001). Socioeconomic variables like age, education level, and annual income did not influence attitude. We recommend environmental education and awareness campaigns outside protected areas, and intensifying existing programs inside protected areas to forge harmonious human‐golden langur coexistence.
Hydrodeoxygenation Using Magnetic Induction: High‐Temperature Heterogeneous Catalysis in Solution
Authors: Asensio Juan M. , Miguel Ana B. , Fazzini Pier‐Francesco , van Leeuwen Piet W. N. M. , Chaudret Bruno 
Published: June 2019

AbstractMagnetic heating has recently been demonstrated as an efficient way to perform catalytic reactions after deposition of the heating agent and the catalyst on a support. Here we show that in solution, and under mild conditions of mean temperature and pressure, it is possible to use magnetic heating to carry out transformations that are otherwise performed heterogeneously at high pressure and/or high temperature. As a proof of concept, we chose the hydrodeoxygenation of acetophenone derivatives and of biomass‐derived molecules, namely furfural and hydroxymethylfurfural. These reactions are difficult, require heterogeneous catalysts and high pressures, and, to the best of our knowledge, have no precedent in standard solution. Here, hydrodeoxygenations are fully selective under mild conditions (3 bar H2, moderate mean temperature of the solvent). The reason for this reactivity is the fast heating of the particles well above the boiling temperature of the solvent and the local creation of hot spots surrounded by a vapor layer, in which high temperature and pressure may be present. This technology may be practicable for many organic transformations.
Bundling mRNA Strands to Prepare Nano‐Assemblies with Enhanced Stability Towards RNase for In Vivo Delivery
Authors: Yoshinaga Naoto , Cho Eol , Koji Kyoko , Mochida Yuki , Naito Mitsuru , Osada Kensuke , Kataoka Kazunori , Cabral Horacio , Uchida Satoshi 
Published: June 2019

AbstractRibonuclease (RNase)‐mediated degradation of messenger RNA (mRNA) poses a huge obstruction to in vivo mRNA delivery. Herein, we propose a novel strategy to protect mRNA by structuring mRNA to prevent RNase attack through steric hinderance. Bundling of mRNA strands through hybridization of RNA oligonucleotide linkers allowed the preparation of mRNA nano‐assemblies (R‐NAs) comprised of 7.7 mRNA strands on average, mostly below 100 nm in diameter. R‐NA formation boosted RNase stability by around 100‐fold compared to naïve mRNA and preserved translational activity, allowing protein production. A mechanistic analysis suggests that an endogenous mRNA unwinding mechanism triggered by 5′‐cap‐dependent translation may induce selective R‐NA dissociation intracellularly, leading to smooth translation. R‐NAs showed efficient mRNA transfection in mouse brain, demonstrating the feasibility for in vivo administration.
Cavity Catalysis by Cooperative Vibrational Strong Coupling of Reactant and Solvent Molecules
Authors: Lather Jyoti , Bhatt Pooja , Thomas Anoop , Ebbesen Thomas W. , George Jino 
Published: June 2019

AbstractHere, we report the catalytic effect of vibrational strong coupling (VSC) on the solvolysis of para‐nitrophenyl acetate (PNPA), which increases the reaction rate by an order of magnitude. This is observed when the microfluidic Fabry–Perot cavity in which the VSC is generated is tuned to the C=O vibrational stretching mode of both the reactant and solvent molecules. Thermodynamic experiments confirm the catalytic nature of VSC in the system. The change in the reaction rate follows an exponential relation with respect to the coupling strength of the solvent, indicating a cooperative effect between the solvent molecules and the reactant. Furthermore, the study of the solvent kinetic isotope effect clearly shows that the vibrational overlap of the C=O vibrational bands of the reactant and the strongly coupled solvent molecules is critical for the catalysis in this reaction. The combination of cooperative effects and cavity catalysis confirms the potential of VSC as a new frontier in chemistry.
Rigid Coplanar Polymers for Stable n‐Type Polymer Thermoelectrics
Authors: Lu Yang , Yu Zi‐Di , Zhang Run‐Zhi , Yao Ze‐Fan , You Hao‐Yang , Jiang Li , Un Hio‐Ieng , Dong Bo‐Wei , Xiong Miao , Wang Jie‐Yu , Pei Jian 
Published: June 2019

AbstractLow n‐doping efficiency and inferior stability restrict the thermoelectric performance of n‐type conjugated polymers, making their performance lag far behind of their p‐type counterparts. Reported here are two rigid coplanar poly(p‐phenylene vinylene) (PPV) derivatives, LPPV‐1 and LPPV‐2, which show nearly torsion‐free backbones. The fused electron‐deficient rigid structures endow the derivatives with less conformational disorder and low‐lying lowest unoccupied molecular orbital (LUMO) levels, down to −4.49 eV. After doping, two polymers exhibited high n‐doping efficiency and significantly improved air stability. LPPV‐1 exhibited a high conductivity of up to 1.1 S cm−1 and a power factor as high as 1.96 μW m−1 K−2. Importantly, the power factor of the doped LPPV‐1 thick film degraded only 2 % after 7 day exposure to air. This work demonstrates a new strategy for designing conjugated polymers, with planar backbones and low LUMO levels, towards high‐performance and potentially air‐stable n‐type polymer thermoelectrics.
Spectroscopic Measurement of a Halogen Bond Energy
Authors: Zhang Xinxing , Liu Gaoxiang , Ciborowski Sandra , Wang Wei , Gong Chu , Yao Yifan , Bowen Kit 
Published: June 2019

AbstractHalogen bonding (XB) has emerged as an important bonding motif in supramolecules and biological systems. Although regarded as a strong noncovalent interaction, benchmark measurements of the halogen bond energy are scarce. Here, a combined anion photoelectron spectroscopy and density functional theory (DFT) study of XB in solvated Br− anions is reported. The XB strength between the positively‐charged σ‐hole on the Br atom of the bromotrichloromethane (CCl3Br) molecule and the Br− anion was found to be 0.63 eV (14.5 kcal mol−1). In the neutral complexes, Br(CCl3Br)1,2, the attraction between the free Br atom and the negatively charged equatorial belt on the Br atom of CCl3Br, which is a second type of halogen bonding, was estimated to have interaction strengths of 0.15 eV (3.5 kcal mol−1) and 0.12 eV (2.8 kcal mol−1).
Iron(II)‐Based Metalloradical Activation: Switch from Traditional Click Chemistry to Denitrogenative Annulation
Authors: Roy Satyajit , Khatua Hillol , Das Sandip Kumar , Chattopadhyay Buddhadeb 
Published: June 2019

AbstractA unique concept for the intermolecular denitrogenative annulation of 1,2,3,4‐tetrazoles and alkynes was discovered by using a catalytic amount of Fe(TPP)Cl and Zn dust. The reaction precludes the traditional, more favored click reaction between an organic azide and alkynes, and instead proceeds by an unprecedented metalloradical activation. The method is anticipated to advance access to the construction of important basic nitrogen heterocycles, which will in turn enable discoveries of new drug candidates.
Sulfur and Ti3+ co‐Doping of TiO2 Nanotubes Enhance Photocatalytic H2 Evolution Without the Use of Any co‐catalyst
Authors: Ji Lei , Zhou Xuemei , Schmuki Patrik 
Published: June 2019

AbstractTiO2 nanotubes were successfully co‐doped with sulfur and Ti3+ states using a facile annealing treatment in H2/H2S gas mixture. The obtained nanotubes were investigated for their photocatalytic performance and characterized by SEM, XRD, XPS, EPR, IPCE, IMPS and Mott‐Schottky measurements. The synthesized co‐doped TiO2 nanotubes show an enhanced photocatalytic hydrogen production rate compared to tubes that were treated only in pure H2 or H2S atmosphere—this without the presence of any co‐catalyst. It was found that sulfur in co‐doped TiO2 exists in the form of S2− and a small quantity of S4+/S6+, which leads to a narrowing of the band gap. However, the enhanced absorption of light in the visible range is not the key reason for the improved photocatalytic performance. We ascribe the enhanced photocatalytic activity to a synergetic effect of S mid‐gap states and disordered Ti3+ defects that facilitate photo generated electron transfer.
Highly Effective Ru/BaCeO3 Catalysts on Supports with Strong Basic Sites for Ammonia Synthesis
Authors: Li Wei , Wang Shuang , Li Jinping 
Published: June 2019

AbstractBaCeO3‐a and BaCeO3‐b, with strong basic sites, were synthesized by using a co‐precipitation method at different calcination temperatures, and used as supports to evaluate their performance in ammonia synthesis. The ammonia synthesis rate with the 1.25 % Ru/BaCeO3‐a catalyst is 24 mmol g−1 h−1, which is higher than that of 1.25 % Ru/BaCeO3‐b catalyst (18 mmol g−1 h−1) at 3 MPa and 450 °C. Moreover, the performance of the 4 % Cs‐1.25 % Ru/BaCeO3‐a catalyst was further improved to 28 mmol g−1 h−1, and no sign of deactivation was observed after a reaction time of 120 h. The XPS and H2 temperature‐programmed reduction analyses indicated that the Ru/BaCeO3‐a catalyst has more oxygen vacancies than the Ru/BaCeO3‐b catalyst. In addition, the average Ru particle size of the Ru/BaCeO3‐a catalyst is closer to 2 nm than the Ru/BaCeO3‐b catalyst, which promotes the generation of B5‐type sites (the active site for N2 dissociation). The CO2 temperature‐programmed desorption analysis indicates that BaCeO3‐a has a high basic density, which is beneficial for electron transfer to Ru and further facilitates the dissociation of N≡N bonds.
Steigerung der Durchstanztragfähigkeit und Duktilität durch die Zugabe moderner Hochleistungsstahlfasern
Authors: Landler Josef , Fischer Oliver 
Published: June 2019

AbstractSeit der Veröffentlichung normativer Vorschriften zur Bemessung von Stahlfaserbeton in Deutschland und Europa gewinnt dessen Einsatz für tragende Konstruktionen des Hoch‐ und Ingenieurbaus stetig an Bedeutung. Nach Eintreten der Rissbildung im Beton ermöglichen Makrofasern aus Stahl eine effektive Übertragung von Zugspannungen über den Riss hinweg, was sich in Bezug auf das Durchstanztragverhalten als besonders vorteilhaft erweist. Während für die Durchstanztragfähigkeit stahlfaserbewehrter Flachdecken mit Plattendicken bis 150 mm zahlreiche Versuchsergebnisse vorliegen, fehlen Untersuchungen an praxisrelevanten Plattenstärken von 200 mm bis 300 mm nahezu gänzlich. Zudem versprechen Fortschritte in der Leistungsfähigkeit moderner Stahldrahtfasern ein verbessertes Trag‐ und Verformungsverhalten des Stahlfaserbetons.Zur Untersuchung des Durchstanztragverhaltens stahlfaserbewehrter Flachdecken mit praxisrelevanten Plattendicken wurden acht Durchstanzversuche an Flachdeckenausschnitten mit unterschiedlichen Plattenstärken durchgeführt. Als weitere Einflussparameter standen der Stahlfasertyp und insbesondere der Stahlfasergehalt im Vordergrund. Der vorliegende Beitrag liefert einen Überblick über die durchgeführten Versuche und diskutiert die gewonnenen Ergebnisse. Anhand eines Vergleichs der experimentell gewonnenen Versagenslasten mit den rechnerischen Durchstanztragfähigkeiten nach der Richtlinie „Stahlfaserbeton“ des Deutschen Ausschusses für Stahlbeton (DAfStb) sowie nach fib Model Code 2010 erfolgt eine Bewertung der Bemessungsansätze.
Withaferin A ameliorates renal injury due to its potent effect on inflammatory signaling
Authors: Peddakkulappagari Chandra S. , Saifi Mohd A. , Khurana Amit , Anchi Pratibha , Singh Mandip , Godugu Chandraiah 
Published: June 2019

AbstractChronic kidney disease (CKD) is one of the major global health concerns and is responsible for end‐stage renal disease (ESRD) complications. Inflammation plays a pivotal role in the progression of CKD. In the present study, we evaluated the renoprotective effects of a potent immunomodulator steroidal lactone, Withaferin A (WfA), in an animal model of renal injury (unilateral ureteral obstruction, UUO) and further investigated if the inhibition of inflammatory signaling can be a useful approach to reduce renal injury. Animals were randomly divided into five groups: Sham control, UUO control, WfA control, WfA low dose (1 mg/kg), and WfA high dose (3 mg/kg). Oxidative stress was measured by the estimation of reduced glutathione and lipid peroxidation levels. H&E and Picrosirius Red staining were performed to assess the extent of histological damage and collagen deposition. Furthermore, the molecular mechanism of the WfA effects was explored by immunohistochemistry, enzyme‐linked immunosorbent assay, multiplex analysis of transforming growth factor β (TGF‐β) pathway, and an array of inflammatory cytokines/chemokines. Interestingly, our pharmacological intervention significantly attenuated tissue collagen, inflammatory signaling, and macrophage signaling. WfA intervention abrogated the inflammatory signaling as evident from the modulated levels of chemokines and cytokines. The levels of TGF‐β along with downstream signaling molecules were also attenuated by WfA treatment as revealed by inhibition in the expression of TGF‐β1, TGF‐β2, p‐Smad2, p‐Smad3, total Smad4, p‐Akt, and p‐ERK. We, to the best of our knowledge, prove for the first time that WfA has potential renoprotective activity against UUO‐induced nephropathy due to its outstanding anti‐inflammatory properties.
Die Wasserlinse – eine unterschätzte Vielzweckpflanze
Authors: Ziegler Paul , Appenroth Klaus‐Jürgen 
Published: June 2019

ZusammenfassungDas rasche Zuwachsen von Gewässeroberflächen macht die unscheinbaren, kleinen Wasserlinsengewächse (Lemnaceae) oft unbeliebt. Doch ihr Wachstumspotential, zusammen mit ihren besonderen morphologischen, klonalen und genomischen Eigenschaften sowie ihrer leichten Kultivierbarkeit machen Wasserlinsen zu wertvollen Modellpflanzen für die Untersuchung von pflanzenwissenschaftlichen Fragestellungen. Zudem wurden sie als Indikatorpflanzen in der aquatischen Ökotoxikologie etabliert. Wasserlinsen können zu der biologischen Reinigung von Abwässern beitragen, und die Biomasse, die ihr Wachstum dabei liefert, kann vielen Zwecken dienen, wie Energie‐ und Treibstoffproduktion sowie Verwendung als Dünger und Futtermittel. Wasserlinsen aus kontrollierter Anzucht können Nahrungsmittel für Menschen darstellen, und sie können auch als biologische Fabriken für die heterologe Proteinexpression dienen. Das vielfältige Nutzungspotential von Wasserlinsen ist noch sehr unvollständig umgesetzt worden: Dies zu tun, ist eine Aufgabe für die Zukunft.
Modellsystem Honigbiene
Authors: Reiter Christian , Kühn Ralph , Nerdel Claudia 
Published: June 2019

ZusammenfassungIm Kontext Honigbiene lässt sich eine nahezu unüberschaubare Bandbreite an Fragestellungen aus unterschiedlichen Perspektiven synergistisch vereinen. Für die Lehre an Schule und Hochschule im Fach Biologie eröffnet das Modellsystem Honigbiene damit einen inhaltlichen Rahmen zur Vernetzung fachlicher Inhalte sowie zur Abstimmung fachlicher, fachdidaktischer, erziehungswissenschaftlicher und schulpraktischer Aspekte und damit zur horizontalen und vertikalen Verknüpfung der Betrachtungsebenen. Im Beitrag werden vier Schülerforschungsprojekte mit dem Modellorganismus Honigbiene aus unterschiedlichen Themenbereichen der Biologie jeweils mit Fokus auf die Bearbeitung authentischer Forschungsfragen vorgestellt.
Aminotenuazonic Acid: Isolation, Structure Elucidation, Total Synthesis and Herbicidal Activity of a New Tetramic Acid from Fruiting Bodies of Laccaria Species
Authors: Schrey Hedda , Backenköhler Jana , Kogler Herbert , Plaumann Markus , Spiteller Peter 
Published: June 2019

Abstract(5S,6S)‐Aminotenuazonic acid, a new 3‐acyltetramic acid, related to the well‐known mycotoxin tenuazonic acid has been isolated from fruiting bodies of Laccaria bicolor. Its structure was mostly established by analysis of its 2D NMR and HR‐(+)‐ESI‐MS spectra. A total synthesis starting from N‐Boc‐l‐isoleucine gave (5S,6S)‐aminotenuazonic acid in 8 % yield over nine steps (67 % de). The key steps of the total synthesis are a light‐initiated Hofmann–Löffler–Freytag radical chain reaction and a Dieckmann cyclisation. The relative and absolute configurations of the natural product were determined by comparison of its NMR and CD spectra with those of the corresponding enantiopure synthetic compounds. Metabolic profiling of crude extracts of different mushrooms showed that aminotenuazonic acid is present in all four of the investigated Laccaria species. Aminotenuazonic acid shows phytotoxic activities against the root and shoot growth of Lepidium sativum, Pinus sylvestris and Arabidopsis thaliana comparable to those of tenuazonic acid.
Photoinitiated Charge Transfer in a Triangular Silver(I) Hydride Complex and Its Oxophilicity
Authors: Kruppa Sebastian V. , Groß Cedric , Gui Xin , Bäppler Florian , Kwasigroch Björn , Sun Yu , Diller Rolf , Klopper Wim , Niedner‐Schatteburg Gereon , Riehn Christoph , Thiel Werner R. 
Published: June 2019

AbstractThe photoexcitation of a triangular silver(I) hydride complex, [Ag3(μ3‐H)(μ2‐dcpm)3](PF6)2 ([P](PF6)2, dcpm=bis(dicyclohexylphosphino)methane), designed with “UV‐silent” bis‐phosphine ligands, provokes hydride‐to‐Ag3 single and double electron transfer. The nature of the electronic transitions has been authenticated by absorption and photodissociation spectroscopy in parallel with high‐level quantum‐chemical computations utilizing the GW method and Bethe–Salpeter equation (GW‐BSE). Specific photofragments of mass‐selected [P]2+ ions testify to charge transfer and competing pathways resulting from the unique [Ag3(μ3‐H)]2+ scaffold. This structural motif of [P](PF6)2 has been unequivocally verified by 1H NMR spectroscopy in concert with DFT and X‐ray diffraction structural analysis, which revealed short equilateral Ag–Ag distances (dAgAg=3.08 Å) within the range of argentophilic interactions. The reduced radical cation [P].+ exhibits strong oxophilicity, forming [P+O2].+,which is a model intermediate for silver oxidation catalysis.
An Electron‐Rich Helical Host for the Exclusive Removal of a Planar Electron‐Deficient Organic Compound
Authors: Kumar Rajesh , Aggarwal Himanshu , Bhowal Rohit , Chopra Deepak , Srivastava Aasheesh 
Published: June 2019

AbstractIn this study, a series of electron‐rich helical hosts, viz. Pyr‐HAC, Anth‐HAC and Ben‐HAC, containing pyrene, anthracene and benzene residues, respectively, at their periphery, were screened for their interaction with different planar electron‐deficient organic guests (PEDOGs). A strong and highly selective charge‐transfer interactions (CTI) was observed between the host Pyr‐HAC and the guest 1,2,4,5‐tetracyano‐benzene (TCNB), leading to a yellow‐to‐bright‐red color change in both the solubilized and the solid state. The interaction between Pyr‐HAC and TCNB also induced profound structural and morphological changes. Pyr‐HAC self‐assembled into belt‐like morphology created by homochiral stacking of the host molecules, but in the Pyr‐HAC⊃TCNB complex, square bipyramids containing intertwined heterochiral C2‐double helices of Pyr‐HAC were observed. Other PEDOGs did not induce any of the above changes in Pyr‐HAC. Detailed UV/Vis absorption and fluorescence spectroscopy, NMR, and X‐ray diffraction studies confirmed this selectivity, which arises due to CTI assisted by complementary, directional intermolecular hydrogen bonding (DIHB) between Pyr‐HAC and TCNB. This allowed for the exclusive extraction of TCNB from a solution enriched in other PEDOGs. Thus, this study provides a ground work for designing responsive helical hosts towards CTI‐driven selective “catch‐and‐release” of guests.