bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanochemical Cycloreversion of Cyclobutane Observed at the Single Molecule Level
Authors: Pill Michael F. , Holz Katharina , Preußke Nils , Berger Florian , Clausen‐Schaumann Hauke , Lüning Ulrich , Beyer Martin K. 
Published: July 2016

AbstractMechanochemical cycloreversion of cyclobutane is known from ultrasound experiments. It is, however, not clear which forces are required to induce the cycloreversion. In atomic force microscopy (AFM) experiments, on the other hand, it is notoriously difficult to assign the ruptured bond. We have solved this problem through the synthesis of tailored macrocycles, in which the cyclobutane mechanophore is bypassed by an ethylene glycol chain of specific length. This macrocycle is covalently anchored between a glass substrate and an AFM cantilever by polyethylene glycol linkers. Upon mechanical stretching of the macrocycle, cycloreversion occurs, which is identified by a defined length increase of the stretched polymer. The measured length change agrees with the value calculated with the external force explicitly included (EFEI) method. By using two different lengths for the ethylene glycol safety line, the assignment becomes unambiguous. Mechanochemical cycloreversion of cyclobutane is observed at forces above 1.7 nN.
1H NMR‐Guided Isolation of Formyl‐Phloroglucinol Meroterpenoids from the Leaves of Eucalyptus robusta
Authors: Shang Zhi‐Chun , Yang Ming‐Hua , Jian Kai‐Li , Wang Xiao‐Bing , Kong Ling‐Yi 
Published: July 2016

AbstractNine formyl‐phloroglucinolmeroterpenoids (FPMs), namely, eucalrobusones A–I (1–9), were isolated from the leaves of Eucalyptus robusta by tracking the phenolic hydroxyl 1H NMR peaks. The Snatzke helicity rules for the Cotton effects of twisted benzene rings were applied to elucidate the absolute configurations of the FPMs. These findings, along with NMR spectroscopy, the circular dichroism (CD) exciton chirality method, and CD calculations, allowed complete structures for the FPMs to be assigned. Eucalrobusones A–F (1–6) are novel adducts formed between a formyl‐derived carbon atom on the phloroglucinol ring and monoterpene and sesquiterpene components. Eucalrobusones G–I (7–9) are the first examples of FPMs with cubebane part structures connected by an unusual 1‐oxaspiro[5.5]undecane subunit. Among these isolates, eucalrobusone C (3) showed significant cytotoxicity against HepG2, MCF‐7, and U2OS cancer cell lines, with IC50 values less than 10 μm. Compound 3 significantly blocks cell proliferation in MCF‐7 cells and induces MCF‐7 cell death through apoptosis.
Toward the Rational Design of Galactosylated Glycoclusters That Target Pseudomonas aeruginosa Lectin A (LecA): Influence of Linker Arms That Lead to Low‐Nanomolar Multivalent Ligands
Authors: Wang Shuai , Dupin Lucie , Noël Mathieu , Carroux Cindy J. , Renaud Louis , Géhin Thomas , Meyer Albert , Souteyrand Eliane , Vasseur Jean‐Jacques , Vergoten Gérard , Chevolot Yann , Morvan François , Vidal Sébastien 
Published: July 2016

AbstractAnti‐infectious strategies against pathogen infections can be achieved through antiadhesive strategies by using multivalent ligands of bacterial virulence factors. LecA and LecB are lectins of Pseudomonas aeruginosa implicated in biofilm formation. A series of 27 LecA‐targeting glycoclusters have been synthesized. Nine aromatic galactose aglycons were investigated with three different linker arms that connect the central mannopyranoside core. A low‐nanomolar (Kd=19 nm, microarray) ligand with a tyrosine‐based linker arm could be identified in a structure–activity relationship study. Molecular modeling of the glycoclusters bound to the lectin tetramer was also used to rationalize the binding properties observed.
High‐Performance Blue OLEDs Based on Phenanthroimidazole Emitters via Substitutions at the C6‐ and C9‐Positions for Improving Exciton Utilization
Authors: Liu Bin , Yuan Yi , He Dan , Huang De‐Yue , Luo Cheng‐Yuan , Zhu Ze‐Lin , Lu Feng , Tong Qing‐Xiao , Lee Chun‐Sing 
Published: July 2016

AbstractDonor–acceptor (D–A) molecular architecture has been shown to be an effective strategy for obtaining high‐performance electroluminescent materials. In this work, two D–A molecules, Ph‐BPA‐BPI and Py‐BPA‐BPI, have been synthesized by attaching highly fluorescent phenanthrene or pyrene groups to the C6‐ and C9‐positions of a locally excited‐state emitting phenylamine–phenanthroimidazole moiety. Equipped with good physical and hybridized local and charge‐transfer properties, both molecules show high performances as blue emitters in nondoped organic light‐emitting devices (OLEDs). An OLED using Ph‐BPA‐BPI as the emitting layer exhibits deep‐blue emission with CIE coordinates of (0.15, 0.08), and a maximum external quantum efficiency (EQE), current efficiency (CE), and power efficiency (PE) of 4.56 %, 3.60 cd A−1, and 3.66 lm W−1, respectively. On the other hand, a Py‐BPA‐BPI‐based, sky‐blue OLED delivers the best results among nondoped OLEDs with CIEy values of < 0.3 reported so far, for which a very low turn‐on voltage of 2.15 V, CIE coordinates of (0.17, 0.29), and maximum CE, PE, and EQE values of 10.9 cd A−1, 10.5 lm W−1, and 5.64 %, were achieved, respectively. More importantly, both devices show little or even no efficiency roll‐off and high singlet exciton‐utilizing efficiencies of 36.2 % for Ph‐BPA‐BPI and 39.2 % for Py‐BPA‐BPI.
Synthesis, Characterization and Properties of Expanded Pyriporphyrins: A New Family of Alkylidenyl Porphyrin Homologues Bearing meso‐Exocyclic Double Bonds
Authors: Abebayehu Abeje , Dutta Ranjan , Lee Chang‐Hee 
Published: July 2016

AbstractWe present the synthesis and characterization of a new family of expanded meso‐alkylidenyl (2,6‐pyri)porphyrinoids bearing multiple exocyclic double bonds at the meso‐positions. The synthesis was accomplished by using mixed pyrrole condensation. Similar to meso‐alkylidenyl porphyrinoids, this study revealed that pyriporphyrinoids do not possess a porphyrin‐like, global‐aromatic character. The synthesized 2,6‐pyripentaphyrin 1 displays selective ratiometric sensing of pyrophosphate anion in organic solvent.
Pt‐Catalyzed Synthesis of Functionalized Symmetrical and Unsymmetrical Disilazanes
Authors: Kuciński Krzysztof , Szudkowska‐Frątczak Justyna , Hreczycho Grzegorz 
Published: July 2016

AbstractIn nearly every total synthesis, silylating agents are employed in synthetic steps to protect sensitive functional groups. A Pt‐catalyzed hydrosilylation of various unsaturated substrates to prepare novel symmetrical and unsymmetrical disilazanes is described. The developed synthetic methodology is widely applicable and tolerates all manner of functional groups (e.g., amines, ethers, esters, halogens, silanes, etc.). To demonstrate the value of the described method, mono‐substituted 1,1,3,3‐tetramethyldisilazanes were further selectively converted to completely new unsymmetrical derivatives.
Near‐Infrared‐Emitting BODIPY‐trisDOTA111In as a Monomolecular Multifunctional Imaging Probe: From Synthesis to In Vivo Investigations
Authors: Maindron Nicolas , Ipuy Martin , Bernhard Claire , Lhenry Damien , Moreau Mathieu , Carme Sabin , Oudot Alexandra , Collin Bertrand , Vrigneaud Jean‐Marc , Provent Peggy , Brunotte François , Denat Franck , Goze Christine 
Published: July 2016

AbstractA new generation of monomolecular imaging probes (MOMIP) based on a distyryl‐BODIPY (BODIPY=boron‐dipyrromethene) coupled with three DOTA macrocycles has been prepared (DOTA=1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid). The MOMIP presents good fluorescence properties and is very stable in serum. The bimodal probe was conjugated to trastuzumab, and an optical in vivo study showed high accumulation of the imaging agent at the tumor site. 111In radiometallation of the bioconjugate was performed in high radiochemical yield, highlighting the potential of this new BODIPY‐chelators derivative as a bimodal imaging probe.
A New Generation of Smart Amine Donors for Transaminase‐Mediated Biotransformations
Authors: Gomm Andrew , Lewis William , Green Anthony P. , O'Reilly Elaine 
Published: July 2016

AbstractThe application of ω‐transaminase biocatalysts for the synthesis of optically pure chiral amines presents a number of challenges, including difficulties associated with displacing the challenging reaction equilibria. Herein, we report a highly effective approach using low equivalents of the new diamine donor, cadaverine, which enables high conversions of challenging substrates to the corresponding chiral amines in excellent ee. This approach paves the way for the design of self‐sufficient fermentation processes combining transaminase biotransformations with existing strategies for cadaverine production by decarboxylation of endogenous lysine.
ZIF‐8 SURMOF Membranes Synthesized by Au‐Assisted Liquid Phase Epitaxy for Application in Gas Separation
Authors: Valadez Sánchez Elvia P. , Gliemann Hartmut , Haas‐Santo Katja , Wöll Christof , Dittmeyer Roland 
Published: July 2016

AbstractMetal‐organic frameworks (MOFs) exhibit a huge potential for gas separation. ZIF‐8 is an interesting candidate due to its high thermal stability and its pore properties. By liquid phase epitaxy, the growth of the highly oriented surface‐anchored MOF ZIF‐8 on non‐porous and porous surfaces has been proven. The preparation of monolithic ZIF‐8 thin films supported by porous α‐Al2O3 substrates modified by a thin layer of Au is investigated. The layer‐by‐layer deposition process accomplished via a dipping procedure results in the formation of defect‐ or crack‐free membranes, preliminary characterized by the determination of ethane and ethene permeance.
Chlorophyll
Authors: Klaproth Anne , Najdanova Maria , Minceva Mirjana , Sicker Dieter , Siehl Hans‐Ullrich , Zeller Klaus‐Peter , Berger Stefan 
Published: July 2016

AbstractChlorophyll existiert seit ca. 3 Mrd. Jahren und steht mit am Beginn der Evolution. Dieser chirale, grüne Magnesium‐Porphyrin‐Komplex absorbiert als Photosensibilisator in den Antennen der Lichtsammelkomplexe der Chloroplasten alle Anteile des sichtbaren Lichts außer Grün. Diese Energie wird an die Reaktionszentren der oxygenen Photosynthese weitergeleitet. In dieser Redoxreaktion entstehen aus Kohlendioxid und Wasser Kohlenhydrate und Sauerstoff. Wir beschreiben die Strukturaufklärung der Chlorophylle, diskutieren Struktur und Eigenschaften, ihre Verwandtschaft zum Häm des Blutes, Alltagsanwendungen und denken über Grünes in der Sprache nach. Die Reinisolierung von Chlorophyll a aus Spinat ist eine experimentelle Herausforderung, die wir im Detail schildern. Alle analytischen Spektren werden vollständig entweder im Hauptteil oder in der supporting information wiedergegeben und interpretiert.
Rational design of a serum‐free culture medium for the growth of human myoblasts destined to cell therapy
Authors: Parent Victor A. , Tremblay Jacques P. , Garnier Alain 
Published: July 2016

AbstractCellular therapy of Duchenne muscular dystrophy is currently showing encouraging results. However, there is still no serum‐free medium that allows multiplying functional myoblasts, the cells required for this therapy, obtained from healthy donors, in sufficient number. A systematic screen for a defined culture medium that would allow expanding fully functional human myoblasts at the same rate and to the same extent as the existing serum‐containing medium has been undertaken. To this end, 6 basal media and more than 60 defined additives have been screened for their individual as well as synergistic effects. The medium developed in this study permits a 12‐log expansion of human myoblasts over a 60‐day period. The cells obtained have the same capacity to fuse and form myofibres as myoblasts multiplied in serum‐containing medium.
16‐Membered Macrolide Lactone Derivatives Bearing a Triazole‐Functionalized Arm at the Aglycone C13 Position as Antibacterial and Anticancer Agents
Authors: Domagalska Joanna , Janas Anna , Pyta Krystian , Pecyna Paulina , Ruszkowski Piotr , Celewicz Lech , Gajecka Marzena , Bartl Franz , Przybylski Piotr 
Published: July 2016

AbstractA series of new C13‐triazole‐bridged and C13‐ether leucomycin analogues with a reduced aldehyde group were synthesized. Derivatives with the highest antibacterial [MIC values (S. epidermidis, S. pneumoniae): ∼2–4 μg mL−1; 2.55–5.09 μm] and cytotoxic [IC50 values (HeLa, KB, MCF‐7, A549, HepG2 cells): ∼1.35–3.70 μm] potencies were those with the best aqueous solubility and bearing a saccharide‐triazole arm at the C13 position of the aglycone. These derivatives preferentially bind at the ribosomal tunnel and show the most attractive selectivity indexes [SI; calculated relative to the human dermal fibroblast (HDF) cell line], even higher than that of the reference compound cytarabine. Results of molecular docking studies of this type of macrolide antibiotics at the ribosomal tunnel, together with experimentally determined lipophilicity and aqueous solubility values, as well as biological assay data revealed the importance of the introduced functional group at the aglycone C13 arm to the future design of anticancer and antibacterial drug candidates. Our results clearly indicate that the high antibacterial and anticancer activities of these types of macrolides do not necessarily depend on the presence of the aldehyde group at the aglycone lactone ring.
Progress in the Development of Lysine Methyltransferase SETD8 Inhibitors
Authors: Milite Ciro , Feoli Alessandra , Viviano Monica , Rescigno Donatella , Mai Antonello , Castellano Sabrina , Sbardella Gianluca 
Published: July 2016

AbstractSETD8/SET8/Pr‐SET7/KMT5A is the only known lysine methyltransferase that monomethylates lysine 20 of histone H4 (H4K20) in vivo. The methyltransferase activity of SETD8 has been implicated in many essential cellular processes, including DNA replication, DNA damage response, transcription modulation, and cell cycle regulation. In addition to H4K20, SETD8 monomethylates non‐histone substrates including proliferating cell nuclear antigen and p53. During the past decade, different structural classes of inhibitors targeting various lysine methyltransferases have been designed and developed. However, the development of SETD8 inhibitors is still in its infancy. This review covers the progress made to date in inhibiting the activity of SETD8 by small molecules, with an emphasis on their discovery, selectivity over other methyltransferases, and cellular activity.
Direct Chemical Fine‐Tuning of Electronic Properties in Sc2Ir6−xPdxB
Authors: Koumoulis Dimitrios , Scheifers Jan P. , St. Touzani Rachid , Fokwa Boniface P. T. , Bouchard Louis‐S. 
Published: July 2016

AbstractCrystal orbital Hamilton population (COHP) bonding analysis has predicted that ScPd3B0.5 is the least stable compound of the entire series Sc2Ir6−xPdxB. Here, we report a systematic study of Sc2Ir6−xPdxB (x=3, 5 and 6) by means of 11B nuclear magnetic resonance (NMR), Knight shift (K) and nuclear spin‐lattice relaxation rate (1/T1). NMR results combined with theoretical band structure calculations provide a measure of s‐ and non‐s‐character Fermi‐level density of states. We present direct evidence that the enhanced s‐state character of the Fermi level density of states (DOS) in ScPd3B0.5 reduces the strength of the B 2p and Pd 4d hybridized states across the entire Sc2Ir6−xPdxB series. This hybridization strength relates to the opening of a deep pseudogap in the density of states of Sc2IrPd5B and the chemical bonding instability of ScPd3B0.5. This study is an experimental realization of a chemical fine‐tuning of the electronic properties in intermetallic perovskites.
Light‐Induced Cell‐Sheet Harvest on TiO2 Films Sensitized with Carbon Quantum Dots
Authors: Wang Xiaozhao , Cheng Kui , Weng Wenjian , Wang Huiming , Lin Jun 
Published: July 2016

AbstractCarbon quantum dots (CQDs) have been incorporated as a sensitizer into TiO2 films to regulate the light‐induced cell‐detachment performance. Depending on the amount of CQDs incorporated, nanodots or porous films are obtained. It was found that the right amount of CQDs incorporation significantly improves the cell‐sheet detachment efficiency, and an intact cell sheet could be obtained after merely five minutes of UV illumination (365 nm, UV365), which is much faster than that from CQDs‐free TiO2 film. Furthermore, cell sheets on CQDs‐sensitized TiO2 films show improved viability, and alkaline phosphatase and collagen I activity either before or after light‐induced detachment. The improved cell‐detachment performance is ascribed to the effective inhibition of charge recombination of the TiO2 film and the microstructure variations, which increase the negative surface potential and change the secondary structure of the adsorbed extracellular protein molecules; this results in a faster release of cells. It is suggested that the faster release reduces the possible detrimental impact on cell functions during detachment and helps in maintaining the excellent cellular activity. This study demonstrates that CQDs sensitization is an effective approach for optimizing the performance of light‐induced cell‐sheet harvest.
A new gain‐of‐function mouse line to study the role of Wnt3a in development and disease
Authors: Chalamalasetty Ravindra B. , Ajima Rieko , Garriock Robert J. , Kennedy Mark W. , Tessarollo Lino , Yamaguchi Terry P. 
Published: July 2016

SummaryWnt/β‐catenin signals are important regulators of embryonic and adult stem cell self‐renewal and differentiation and play causative roles in tumorigenesis. Purified recombinant Wnt3a protein, or Wnt3a‐conditioned culture medium, has been widely used to study canonical Wnt signaling in vitro or ex vivo. To study the role of Wnt3a in embryogenesis and cancer models, we developed a Cre recombinase activatable Rosa26Wnt3a allele, in which a Wnt3a cDNA was inserted into the Rosa26 locus to allow for conditional, spatiotemporally defined expression of Wnt3a ligand for gain‐of‐function (GOF) studies in mice. To validate this reagent, we ectopically overexpressed Wnt3a in early embryonic progenitors using the T‐Cre transgene. This resulted in up‐regulated expression of a β‐catenin/Tcf‐Lef reporter and of the universal Wnt/β‐catenin pathway target genes, Axin2 and Sp5. Importantly, T‐Cre; Rosa26Wnt3a mutants have expanded presomitic mesoderm (PSM) and compromised somitogenesis and closely resemble previously studied T‐Cre; Ctnnb1ex3 (β‐cateninGOF) mutants. These data indicate that the exogenously expressed Wnt3a stimulates the Wnt/β‐catenin signaling pathway, as expected. The Rosa26Wnt3a mouse line should prove to be an invaluable tool to study the function of Wnt3a in vivo.
Modeling stream fish distributions using interval‐censored detection times
Authors: Ferreira Mário , Filipe Ana Filipa , Bardos David C. , Magalhães Maria Filomena , Beja Pedro 
Published: July 2016

AbstractControlling for imperfect detection is important for developing species distribution models (SDMs). Occupancy‐detection models based on the time needed to detect a species can be used to address this problem, but this is hindered when times to detection are not known precisely. Here, we extend the time‐to‐detection model to deal with detections recorded in time intervals and illustrate the method using a case study on stream fish distribution modeling. We collected electrofishing samples of six fish species across a Mediterranean watershed in Northeast Portugal. Based on a Bayesian hierarchical framework, we modeled the probability of water presence in stream channels, and the probability of species occupancy conditional on water presence, in relation to environmental and spatial variables. We also modeled time‐to‐first detection conditional on occupancy in relation to local factors, using modified interval‐censored exponential survival models. Posterior distributions of occupancy probabilities derived from the models were used to produce species distribution maps. Simulations indicated that the modified time‐to‐detection model provided unbiased parameter estimates despite interval‐censoring. There was a tendency for spatial variation in detection rates to be primarily influenced by depth and, to a lesser extent, stream width. Species occupancies were consistently affected by stream order, elevation, and annual precipitation. BayesianP‐values andAUCs indicated that all models had adequate fit and high discrimination ability, respectively. Mapping of predicted occupancy probabilities showed widespread distribution by most species, but uncertainty was generally higher in tributaries and upper reaches. The interval‐censored time‐to‐detection model provides a practical solution to model occupancy‐detection when detections are recorded in time intervals. This modeling framework is useful for developingSDMs while controlling for variation in detection rates, as it uses simple data that can be readily collected by field ecologists.
Electrochemical and Surface Characterization of Dense Monolayers Grafted on ITO and Si/SiO2 Surfaces via Tetra(tert‐Butoxy)Tin Linker
Authors: Petrizza Luca , Genovese Damiano , Valenti Giovanni , Iurlo Matteo , Fiorani Andrea , Paolucci Francesco , Rapino Stefania , Marcaccio Massimo 
Published: July 2016

AbstractIndium tin oxide (ITO) and silicon with a thermally grown SiO2 layer (Si/SiO2) substrates have been functionalized by ferrocene bound through Sn(O)x (x=2 or 3) linkers preliminarly grafted on the surface by reaction of the terminal hydroxyl groups with tetra(tert‐butoxy)tin. The two steps modification of the surface was carried out by chemical vapour deposition metathesis reaction producing a self‐assembled monolayer of ferrocene. The ITO and Si/SiO2 thus functionalized have been characterized by voltammetric, amperometric, electrochemical impedance spectroscopy and scanning probe microscopy techniques which assessed the formation of a stable and rather compact covalently bound ferrocenyl monolayer with improved electron transfer properties.
Quantification of oxygen production and respiration rates in mixotrophic cultivation of microalgae in nonstirred photobioreactors
Authors: Schwerna Philipp , Hübner Holger , Buchholz Rainer 
Published: July 2016

Online monitoring and controlling of different cellular parameters are key issues in aerobic bioprocesses. Since mixotrophic cultivation, in which we observe a mixture of cellular respiration and oxygen production has gained more popularity, there is a need for an on‐process quantification of these parameters. The presented and adapted double gassing‐out method applied to a mixotrophic cultivation of Galdieria sulphuraria, will be a tool for monitoring and further optimization of algal fermentation in nonstirred photobioreactors (PBR). We measured the highest net specific oxygen production rate (oprnet) as 5.73 · 10−3 molO2 g−1 h−1 at the lowest oxygen uptake rate (OUR) of 1.00 · 10−4 molO2 L−1 h−1. Due to higher cell densities, we also demonstrated the increasing shading effect by a decrease of oprnet, reaching the lowest value of 1.25 10−5 molO2 g−1 h−1. Nevertheless, with this on process measurement, we can predict the relation between the zone in which oxygen is net produced to the area where cell respiration dominates in a PBR, which has a major impact to optimize cell growth along with the formation of different products of interest such as pigments.