bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differences between the Interactions of Linear and Tetrahedron‐like Ditopic Guests with Cucurbit[8]uril: Steric Hindrance and Molecular Structure Play Dominant Roles
Authors: Hou Shengzhen , Chen Hao , Ma Haili , Tan Yebang 
Published: January 2017

AbstractA tetrahedron‐like guest molecule (THV) with four ditopic arms, consisting of viologen (V) and hexylene moieties, was synthesized, and its interaction with cucurbit[8]uril (CB[8]) was investigated. As a reference, the interaction between CB[8] and an analogue of the arm of the linear ditopic guest (LHV) was first explored by 1H NMR and UV/Vis spectroscopy. In this case, CB[8] was located on the hexylene moiety and resulted in the formation of a binary complex. However, when THV interacted with CB[8], despite having four arms with four hexylene moieties, only two CB[8] molecules were identified as located on the hexylene moieties; the other two CB[8] molecules resided on the V moieties. Great steric hindrance among the arms played a dominant role in the interaction between THV and CB[8]. Regardless of whether the guest molecule was THV or LHV, CB[8] moved to its V moiety (electron‐deficient part) to form the charge‐transfer complex upon the addition of a stopper containing a naphthol residue (electron‐rich part). Guests LHV and THV were reduced to LHV+(+.) and THV+4(+.) upon the addition of sodium dithionite. Dimerization of LHV+(+.) was enhanced when CB[8] was present in less than 0.5 equivalents. In contrast, dimerization was suppressed when CB[8] was present in more than 0.5 equivalents. However, the V+. units of THV+4(+.) stacked intramolecularly because of the tetrahedron‐like molecular structure of THV. The influence of CB[8] on the dimerization of THV+4(+.) was weaker than that on LHV+(+.).
Planung und Bau der neuen Eisenbahnbrücke über den Neckar – Herausforderungen bei der Gründung
Authors: Lienhart Christoph , Heer Sebastian , Wenger Philipp , Zimmerer Martin 
Published: January 2017

AbstractIm Rahmen des Infrastrukturprojekts Stuttgart 21 errichtet die Deutsche Bahn in Stuttgart seit Anfang 2016 eine viergleisige Eisenbahnbrücke über den Neckar. Die Eisenbahnbrücke hat eine Gesamtlänge von ca. 345 m und führt über zwei Widerlager und sechs Pfeiler‐Achsen.Das Bauwerk überquert Stadtbahngleise, die Bundesstraße B 10, innerstädtische Straßen, den Neckar, Fuß‐ und Radwege sowie diverse Leitungen. Das Bauvorhaben liegt in der Kernzone des Stuttgarter Heilquellenschutzgebiets mit strengsten Auflagen hinsichtlich zulässiger Eingriffe in den Baugrund und Grundwasserhaltungen. Die Heilquellen liegen im Baufeld ca. 26 m unter Gelände als artesischer Grundwasserleiter mit einem Druckspiegel von rd. 10 m über Gelände vor.Als schonendste Gründungsvariante der drei Hauptpfeiler hinsichtlich wasserwirtschaftlicher Aspekte wurde nach Auswertung der ersten fünf Baugrunderkundungsprogramme eine Flachgründung auf den Schichten des Unterkeupers mittels Druckluftgründung in Deckelbauweise angesehen. Im Zuge der Ausführungsplanung wurden die hydrochemischen und bodenmechanischen Eigenschaften des Baugrunds mit einem ergänzenden Erkundungsprogramm untersucht. Nach Auswertung aller zur Verfügung stehenden Erkundungsergebnisse konnte von einer Druckluftgründung auf eine wirtschaftlichere Tiefgründungsvariante mit Großbohrpfählen umgeplant werden. Um eine Genehmigung der erforderlichen Eingriffstiefen in der Kernzone des Heilquellenschutzgebiets zu erhalten, mussten im Vorfeld Handlungskonzepte für unterschiedliche Szenarien bei der Herstellung der Großbohrpfähle ausgearbeitet werden.
Metal‐Assisted Folding of Prolinomycin Allows Facile Design of Functional Peptides
Authors: Hosseini Azade S. , Wang Wenjian , Haeffner Fredrik , Gao Jianmin 
Published: January 2017

AbstractCyclic peptides have been proposed as privileged scaffolds that might mimic the folding and function of natural proteins. However, simple cyclic peptides typically cannot fold into well‐defined structures. Herein, we describe a foldable cyclic peptide scaffold on which functional side chains can be displayed for targeted recognition of biomolecules. The foldable scaffold is based on prolinomycin, a proline‐rich analogue of valinomycin. We report synthetic mutants of prolinomycin that retain the metal‐assisted folding behavior under physiological conditions. The predictable structure formation of prolinomycin makes it a powerful platform to enable the development of synthetic receptors for biomolecules of interest. We demonstrate the potential of this scaffold by creating prolinomycin mutants that selectively bind anionic vesicles and bacterial cells.
Photocatalytic CO2 Reduction Under Continuous Flow High‐Purity Conditions: Quantitative Evaluation of CH4 Formation in the Steady‐State
Authors: Dilla Martin , Schlögl Robert , Strunk Jennifer 
Published: January 2017

AbstractIn this study, the photocatalytic CO2 reduction on TiO2 P25 was investigated for the first time under high‐purity continuous flow conditions with gas chromatographic (GC) online detection of CH4 as the main product. The thorough photocatalytic cleaning procedure in humid helium prior to all measurements was conducted under continuous flow too and we were able to monitor the decrease of carbonaceous contaminant concentration. On addition of CO2 to the feed under illumination, an increase in CH4 concentration was observed, which clearly follows the increase in CO2 concentration in the reactor. It was also demonstrated that CH4 formation ceases as soon as the lamp is switched off, providing clear evidence that the formation of CH4 from CO2 is a photoinduced process. It was shown that higher CO2 concentration accelerated CH4 formation under steady‐state conditions up to a certain optimum. Higher CO2 concentrations lead to a decrease in CH4 formation. This observation is tentatively assigned to a limited availability of photogenerated charge carriers at the TiO2 surface, or a lack of suitable catalytically active sites. Traces of O2 in the reactor completely hinder CH4 formation, implying that the lack of concomitant oxygen evolution observed in previous measurements on TiO2 is likely beneficial for the overall process. This study represents a first step towards performing true steady‐state kinetic studies of photocatalytic CO2 reduction.
Ultrapure Molybdenum Disulfide Shows Enhanced Catalysis for Hydrogen Evolution over Impurities‐Doped Counterpart
Authors: Toh Rou Jun , Sofer Zdenek , Luxa Jan , Pumera Martin 
Published: January 2017

AbstractThe development of electrocatalysts to meet the requirements of renewable energy applications has seen much attention placed on transition‐metal dichalcogenide (TMD) materials owing to their promising properties. In particular, the strategy of atomic doping has garnered some success in tuning the electronic properties and harnessing the vast potential that TMDs can offer in the catalysis of the hydrogen evolution reaction (HER). Moreover, with computational studies reporting the promising effects of transition‐metal doping, such a strategy has been adopted with much enthusiasm. Herein, we consider one of the most prevalent TMDs, that is, MoS2, and the possible presence of impurities arising from its preparation method and starting materials that may act as dopants to affect its electronic and catalytic properties. An ultrapure MoS2 material was synthesized and compared with a relatively impure MoS2 sample obtained commercially. Ultrapure MoS2 was found to outperform its impurities‐doped counterpart in HER catalysis. These findings not only provide valuable insight into the influence of parts‐per‐million concentrations of impurities on the catalytic activity of TMD materials but also highlight the importance of the intentional and proper design of atomic doping to realize its true effects. At the same time, the need for a more in‐depth understanding and evaluation of the benefits of the atomic‐doping strategy in the experimental setting as a means to harness the potential of TMDs as catalysts for hydrogen evolution is also revealed.
New AdoMet Analogues as Tools for Enzymatic Transfer of Photo‐Cross‐Linkers and Capturing RNA–Protein Interactions
Authors: Muttach Fabian , Mäsing Florian , Studer Armido , Rentmeister Andrea 
Published: January 2017

AbstractElucidation of biomolecular interactions is of utmost importance in biochemistry. Photo‐cross‐linking offers the possibility to precisely determine RNA–protein interactions. However, despite the inherent specificity of enzymes, approaches for site‐specific introduction of photo‐cross‐linking moieties into nucleic acids are scarce. Methyltransferases in combination with synthetic analogues of their natural cosubstrate S‐adenosyl‐l‐methionine (AdoMet) allow for the post‐synthetic site‐specific modification of biomolecules. We report on three novel AdoMet analogues bearing the most widespread photo‐cross‐linking moieties (aryl azide, diazirine, and benzophenone). We show that these photo‐cross‐linkers can be enzymatically transferred to the methyltransferase target, that is, the mRNA cap, with high efficiency. Photo‐cross‐linking of the resulting modified mRNAs with the cap interacting protein eIF4E was successful with aryl azide and diazirine but not benzophenone, reflecting the affinity of the modified 5′ caps.
Gaining Synthetic Appreciation for the Gedunin ABC Ring System
Authors: Pinkerton David M. , Vanden Berg Timothy J. , Bernhardt Paul V. , Williams Craig M. 
Published: January 2017

AbstractGedunin, first isolated in 1960, displays a remarkable range of biological activity, but has yet to receive dedicated synthetic attention from a ground up construction perspective. Presented herein is a successfully executed approach to the fully functionalized ABC ring system of this challengingly complex natural product.
Versatile Dynamic Covalent Assemblies for Probing π‐Stacking and Chirality Induction from Homotopic Faces
Authors: Ye Hebo , Hai Yu , Ren Yulong , You Lei 
Published: January 2017

AbstractHerein we report for the first time the use of dynamic covalent reactions (DCRs) for building a π‐stacking model system and further quantifying its substituent effects (SEs), which remain a topic of debate despite the rich history of stacking. A general DCR between 10‐methylacridinium ion and primary amines was discovered, in which π‐stacking played a stabilizing role. Facile quantification of SEs with in situ competing π‐stacking systems was next achieved in the form of amine exchange exhibiting structural diversity by simply varying components. The linear correlation with σm in Hammett plots indicates the dominance of purely electrostatic SEs, and the additivity of SEs is in line with the direct interaction model. With α‐chiral amines π‐stacking within the adduct enabled chirality transfer from homotopic faces. The strategy of dynamic covalent assembly should be appealing to future research of probing weak interactions and manipulating chirality.
Laser‐Assisted Synthesis of Colloidal Ni/NiOx Core/Shell Nanoparticles in Water and Alcoholic Solvents
Authors: Lasemi Niusha , Pacher Ulrich , Rentenberger Christian , Bomatí‐Miguel Oscar , Kautek Wolfgang 
Published: January 2017

AbstractThe nanosecond‐pulse laser‐assisted generation of Ni/NiOx core/shell nanoparticles (NPs) in water and alcoholic fluids can yield colloidal solutions without surfactants. The size distribution can be controlled by the nature of the alcohol, the number of laser pulses and the laser fluence. The incubation of the nickel target ablation in liquid contact shows a dependence on the carbon number of the respective alcohol. The laser‐generated NPs consist of crystalline nickel cores with face‐centred cubic patterns and stacking fault defects surrounded by nickel oxide shells. The solvent butanol, in contrast to ethanol and isopropanol, yields a narrow, nearly unimodal, size distribution. The majority of NPs have low size distributions, with medians in the range of 10–20 nm. These can be related to a metal ablation plume interacting with a supercritical liquid that decelerates the ejected material in a low‐density metal–water mixing region. NPs in the range above 30 nm result in a minority distribution tail that strongly depends on the fluid nature, the pulse number and the fluence. This coarse NP set may be correlated with the rupture of a superheated molten‐metal layer into larger entities.
Stimuli‐Responsive Polymers for Actuation
Authors: Zhang Qiang Matthew , Serpe Michael J. 
Published: January 2017

AbstractA variety of stimuli‐responsive polymers have been developed and used as actuators and/or artificial muscles, with the movement being driven by an external stimulus, such as electrical potential. This Review highlights actuators constructed from liquid‐crystal elastomers, dielectric elastomers, ionic polymers, and conducting polymers. The Review covers recent examples of a variety of actuators generated from these materials and their utility. The mechanism of actuation will be detailed for most examples in order to stimulate possible future research, and lead to new applications and advanced applications.
An Interactive Quantum Dot and Carbon Dot Conjugate for pH‐Sensitive and Ratiometric Cu2+ Sensing
Authors: Ahmad Kafeel , Gogoi Sonit Kumar , Begum Raihana , Sk Md Palashuddin , Paul Anumita , Chattopadhyay Arun 
Published: January 2017

AbstractHerein we report the photoinduced electron transfer from Mn2+‐doped ZnS quantum dots (Qdots) to carbon dots (Cdots) in an aqueous dispersion. We also report that the electron transfer was observed for low pH values, at which the oppositely charged nanoparticles (NPs) interacted with each other. Conversely, at higher pH values the NPs were both negatively charged and thus not in contact with each other, so the electron transfer was absent. Steady‐state and time‐resolved photoluminescence studies revealed that interacting particle conjugates were responsible for the electron transfer. The phenomenon could be used to detect the presence of Cu2+ ions, which preferentially, ratiometrically, and efficiently quenched the luminescence of the Qdots.
Lignin‐Based Materials Through Thiol–Maleimide “Click” Polymerization
Authors: Buono Pietro , Duval Antoine , Averous Luc , Habibi Youssef 
Published: January 2017

AbstractIn the present report an environmentally friendly approach to transforming renewable feedstocks into value‐added materials is proposed. This transformation pathway was conducted under green conditions, without the use of solvents or catalyst. First, controlled modification of lignin, a major biopolymer present in wood and plants, was achieved by esterification with 11‐maleimidoundecylenic acid (11‐MUA), a derivative from castor oil that contains maleimide groups, following its transformation into 11‐maleimidoundecanoyl chloride (11‐MUC). Different degrees of substitution were achieved by using various amounts of the 11‐MUC, leading to an efficient conversion of lignin hydroxy groups, as demonstrated by 1H and 31P NMR analyses. These fully biobased maleimide‐lignin derivatives were subjected to an extremely fast (ca. 1 min) thiol–ene “click” polymerization with thiol‐containing linkers. Aliphatic and aromatic thiol linkers bearing two to four thiol groups were used to tune the reactivity and crosslink density. The properties of the resulting materials were evaluated by swelling tests and thermal and mechanical analyses, which showed that varying the degree of functionality of the linker and the linker structure allowed accurate tailoring of the thermal and mechanical properties of the final materials, thus providing interesting perspectives for lignin in functional aromatic polymers.
Out of Africa: Biogeography and diversification of the pantropical pond skater genus Limnogonus Stål, 1868 (Hemiptera: Gerridae)
Authors: Ye Zhen , Zhen Yahui , Zhou Yanyan , Bu Wenjun 
Published: January 2017

AbstractGondwanan vicariance, long‐distance dispersal (LDD), and boreotropical migration have been proposed as alternative hypotheses explaining the pantropical distribution pattern of organisms. In this study, the historical biogeography of the pond skater genus Limnogonus was reconstructed to evaluate the impact of biogeographical scenarios in shaping their modern transoceanic disjunction. We sampled almost 65% of recognized Limnogonus species. Four DNA fragments including 69 sequences were used to reconstruct a phylogram. Divergence time was estimated using a Bayesian relaxed clock method and three fossil calibrations. Diversification dynamics and ancestral area reconstruction were investigated by using maximum likelihood and Bayesian approaches. Our results showed the crown group of Limnogonus originated and diversified in Africa in the early Eocene (49 Ma, HPD: 38–60 Ma), subsequently expanding into other regions via dispersal. The colonization of the New World originated from the Oriental Region probably via the Bering Land Bridge in the late Eocene. Two split events between the Old World and New World were identified: one between Neotropics and Oriental region around the middle Oligocene (30 Ma, HPD: 22–38 Ma), and the other between Neotropics and Africa during the middle Miocene (14 Ma, HPD: 8–21 Ma). The evolutionary history of Limnogonus involved two biogeographical processes. Gondwanan vicariance was not supported in our analyses. The diversification of Limnogonus among Africa, Oriental, and Neotropical regions corresponded with the age of land bridge connection and dispersed as a member associated with the broad boreotropical belt before local cooling (34 Ma). The current transoceanic disjunctions in Limnogonus could be better explained by the disruption of “mixed‐mesophytic” forest belt; however, the direct transoceanic LDD between the Neotropics and Africa could not be ruled out. In addition, the “LDD” model coupled with island hopping could be a reasonable explanation for the diversification of the Oriental and Australian regions during the Oligocene.
The use of ATR‐FTIR spectroscopy to measure changes in the oxirane content and iodine value of vegetable oils during epoxidation
Authors: Tavassoli‐Kafrani Mohammad Hossein , van de Voort Frederik R. , Curtis Jonathan M. 
Published: January 2017

A rapid attenuated total reflectance Fourier transform infrared (ATR‐FTIR) method was developed to simultaneously measure for vegetable oils both their oxirane oxygen content (OOC) and the change in their iodine values (IV) that occur during their epoxidation. The method uses the peak area of the epoxy functional group absorption (1497.3–1432.0 cm−1) to measure OOC and the HCabsorption associated with a carbon–carbon double bond (3017.5–3004.2 cm−1) to determine the relative changes in iodine value (ΔIV). Calibrations were developed by gravimetrically blending epoxidized canola oil (ECO) with unreacted canola oil (CO) to vary both OOC and IV. Oils including canola, camelina, and flaxseed were epoxidized, during which the OOC and ΔIV were tracked as a function of time using both the new ATR‐FTIR procedures and the standard ASTM methods. Both the OOC and ΔIV values measured by the ATR‐FTIR method correlate well to values from standard methods (R2 ≥ 0.992 and mean relative error of <3%). The FTIR procedure is simple and fast to perform and facilitates the determination of selectivity (conversion of double bonds into oxirane group) and the end‐point for the epoxidation reaction, which requires measurement of both OOC and IV.Practical applications: The ATR‐FTIR method described provides a simple, rapid, and accurate means for the measurement of OOC as well as changes in iodine value during the epoxidation of vegetable oils. This allows for the determination of the degree of conversion of lipid unsaturation into epoxides. This method can be employed by manufacturers and research laboratories to study, control, and optimize epoxidation processes.The ATR‐FTIR methods described in this paper provide a simple and rapid means of monitoring OOC and IV changes during the epoxidation of vegetable oils. These methods are calibrated against standard titrimetric procedures and have been shown to produce similar results. It is especially useful that OOC and ΔIV, the two measures that are most relevant for monitoring the progress of a triacylglycerol oil epoxidation reaction, can be obtained from a single analysis. This facilitates monitoring and optimizing epoxidation processes. If the initial IV of oil is known, the method can also be used to calculate the yield, conversion, and selectivity of the reaction, as well as a study the reaction kinetics.
ALL OUR SONS: THE DEVELOPMENTAL NEUROBIOLOGY AND NEUROENDOCRINOLOGY OF BOYS AT RISK
Authors: Schore Allan N. 
Published: January 2017

ABSTRACTWhy are boys at risk? To address this question, I use the perspective of regulation theory to offer a model of the deeper psychoneurobiological mechanisms that underlie the vulnerability of the developing male. The central thesis of this work dictates that significant gender differences are seen between male and female social and emotional functions in the earliest stages of development, and that these result from not only differences in sex hormones and social experiences but also in rates of male and female brain maturation, specifically in the early developing right brain. I present interdisciplinary research which indicates that the stress‐regulating circuits of the male brain mature more slowly than those of the female in the prenatal, perinatal, and postnatal critical periods, and that this differential structural maturation is reflected in normal gender differences in right‐brain attachment functions. Due to this maturational delay, developing males also are more vulnerable over a longer period of time to stressors in the social environment (attachment trauma) and toxins in the physical environment (endocrine disruptors) that negatively impact right‐brain development. In terms of differences in gender‐related psychopathology, I describe the early developmental neuroendocrinological and neurobiological mechanisms that are involved in the increased vulnerability of males to autism, early onset schizophrenia, attention deficit hyperactivity disorder, and conduct disorders as well as the epigenetic mechanisms that can account for the recent widespread increase of these disorders in U.S. culture. I also offer a clinical formulation of early assessments of boys at risk, discuss the impact of early childcare on male psychopathogenesis, and end with a neurobiological model of optimal adult male socioemotional functions.
ASSOCIATIONS BETWEEN EARLY MATERNAL DEPRESSIVE SYMPTOM TRAJECTORIES AND TODDLERS’ FELT SECURITY AT 18 MONTHS: ARE BOYS AND GIRLS AT DIFFERENTIAL RISK?
Authors: Beeghly Marjorie , Partridge Ty , Tronick Ed , Muzik Maria , Rahimian Mashhadi Mahya , Boeve Jordan L. , Irwin Jessica L. 
Published: January 2017

ABSTRACTThe goal of this study was to evaluate whether there are sex differences in children's vulnerability to caregiving risk, as indexed by trajectories of maternal depressive symptoms assessed from 2 to 18 months’ postpartum, and children's rated attachment security in toddlerhood, adjusting for maternal social support and demographic risk. Analyses utilized longitudinal data collected for 182 African American mother–child dyads from economically diverse backgrounds. Participants were recruited at the time of the child's birth and followed to 18 months’ postpartum. Results of conditional latent growth models indicated that an increasing rate of change in level of maternal depressive symptoms over time negatively predicted toddlers’ felt attachment security. Higher social support was associated with decreasing levels of maternal depressive symptoms over time whereas higher demographic risk was associated with increasing levels of maternal depressive symptoms. A subsequent multigroup conditional latent growth model revealed that child sex moderated these associations. For male (but not female) children, a rapid increase in maternal depressive symptoms was associated with lower felt attachment security at 18 months. These findings suggest that boys, as compared to girls, may be more vulnerable to early caregiving risks such as maternal depression, with negative consequences for mother–child attachment security in toddlerhood.