bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lewis Acid‐Mediated [3+3] Annulation for the Construction of Substituted Pyrimidine and Pyridine Derivatives
Authors: Zhou Yao , Tang Zhonghe , Song Qiuling 
Published: January 2017

AbstractA direct and single‐step procedure towards substituted pyrimidine and pyridine derivatives via Lewis acid‐promoted [3+3] annulation between 3‐ethoxycyclobutanones and enamines or amidines is presented. Diverse substituted pyrimidine and pyridine derivatives were obtained in good to high yields with a wide substrate scope.magnified image
The Pathways Between Socioeconomic Status and Adolescent Outcomes: A Systematic Review
Authors: Devenish Bethany , Hooley Merrilyn , Mellor David 
Published: January 2017

AbstractSocioeconomic status (SES) is a significant risk factor for negative adolescent development outcomes. Identifying the pathways between SES and these outcomes may inform interventions for adolescents from this demographic. We conducted a systematic literature review of eight databases for studies investigating pathways between SES and adolescent psychosocial outcomes. A total of 59 articles met inclusion criteria. Significant risk factors identified include economic stress, chaos in the home, and violence in the community. These risk factors appear to be mediated through parent depression, conflict between parents, parenting practices, and adolescent resilience. Interventions focusing on the identified risk factors are recommended.
Einschaltbare Fluoreszenz in Tetra‐NHC‐Liganden durch Versteifung bei der Komplexbildung: eine Alternative zu aggregationsinduzierter Emission
Authors: Sinha Narayan , Stegemann Linda , Tan Tristan T. Y. , Doltsinis Nikos L. , Strassert Cristian A. , Hahn F. Ekkehardt 
Published: January 2017

AbstractMit den Tetraphenylethylen(TPE)‐verbrückten Tetraimidazolium‐Salzen [H4L‐Et](PF6)4 und [H4L‐Bu](PF6)4 wurden die zweikernigen AgI‐ und AuI‐Tetracarben‐Komplexe [Ag2(L‐Et)](PF6)2, [Ag2(L‐Bu)](PF6)2, [Au2(L‐Et)](PF6)2 und [Au2(L‐Bu)](PF6)2 synthetisiert. In verdünnter Lösung zeigen die Tetraimidazolium‐Salze fast keine Fluoreszenz (ΦF<1 %), während die NHC‐Komplexe stark fluoreszieren (ΦF bis zu 47 %). Die Komplexbildung führt zur Versteifung der TPE‐Einheit und zur Verhinderung der intramolekulare Rotation innerhalb der TPE‐Einheit. DFT‐Rechnungen bestätigen, dass die Metalle nicht an der Ausbildung der niedrigsten angeregten Singulett‐ und Triplett‐Zustände beteiligt sind, was auch die Abwesenheit von Phosphoreszenz erklärt. Die Versteifung durch Komplexbildung stellt eine Alternative zum bekannten aggregationsinduzierten Fluoreszenz‐“Einschalten” dar.
Ferromagnetic Interactions in Highly Stable, Partially Reduced TiO2: The S=2 State in Anatase
Authors: Chiesa Mario , Livraghi Stefano , Giamello Elio , Albanese Elisa , Pacchioni Gianfranco 
Published: January 2017

AbstractWe report direct evidence for quintuplet spin states in a particular kind of reduced TiO2 anatase obtained by the mild oxidation of TiB2 under hydrothermal conditions. Continuous‐wave and pulse EPR spectroscopy at X and Q band frequencies provide compelling evidence for the presence of S=2 states, stable in a wide range of temperatures up to room temperature. A tentative model, corroborated by spin‐polarized DFT calculations, is proposed, which consists of four ferromagnetically interacting Ti3+ ions with distances ranging from 0.5 nm to 0.8 nm and tetrahedral arrangement.
Biokatalytische Totalsynthese von Ikarugamycin
Authors: Greunke Christian , Glöckle Anna , Antosch Janine , Gulder Tobias A. M. 
Published: January 2017

AbstractDie Natur stellt eine unerschöpfliche Diversität organischer Moleküle mit beeindruckenden Architekturen bereit, die starke und selektive Bioaktivitäten aufweisen. Jedoch bleibt das damit verbundene, enorme biomedizinische Potential oft unzugänglich, da die strukturelle Komplexität von Naturstoffen deren Synthese extrem anspruchsvoll macht. Dieses Problem kann mithilfe des von der Natur evolvierten enzymatischen Werkzeugkastens adressiert werden. In dieser Arbeit präsentieren wir eine biokatalytische Totalsynthese des Ikarugamycins. Unter Verwendung einer iterativen PKS/NRPS‐Maschinerie und zweier Reduktasen werden in einer biokatalytischen Eintopfreaktion fünfzehn C‐C‐ und zwei C‐N‐Bindungen aufgebaut. Durch Skalierung dieser Methode demonstrieren wir die Anwendbarkeit biokatalytischer Ansätze zur Ex‐vivo‐Synthese komplexer Naturstoffe.
From Genome to Proteome to Elucidation of Reactions for All Eleven Known Lytic Transglycosylases from Pseudomonas aeruginosa
Authors: Lee Mijoon , Hesek Dusan , Dik David A. , Fishovitz Jennifer , Lastochkin Elena , Boggess Bill , Fisher Jed F. , Mobashery Shahriar 
Published: January 2017

AbstractAn enzyme superfamily, the lytic transglycosylases (LTs), occupies the space between the two membranes of Gram‐negative bacteria. LTs catalyze the non‐hydrolytic cleavage of the bacterial peptidoglycan cell‐wall polymer. This reaction is central to the growth of the cell wall, for excavating the cell wall for protein insertion, and for monitoring the cell wall so as to initiate resistance responses to cell‐wall‐acting antibiotics. The nefarious Gram‐negative pathogen Pseudomonas aeruginosa encodes eleven LTs. With few exceptions, their substrates and functions are unknown. Each P. aeruginosa LT was expressed as a soluble protein and evaluated with a panel of substrates (both simple and complex mimetics of their natural substrates). Thirty‐one distinct products distinguish these LTs with respect to substrate recognition, catalytic activity, and relative exolytic or endolytic ability. These properties are foundational to an understanding of the LTs as catalysts and as antibiotic targets.
Hyper‐Crosslinkers Lead to Temperature‐ and pH‐Responsive Polymeric Nanogels with Unusual Volume Change
Authors: Zhou Ning , Cao Xiaoyan , Du Xuewen , Wang Huaimin , Wang Ming , Liu Shuang , Nguyen Khang , Schmidt‐Rohr Klaus , Xu Qiaobing , Liang Gaolin , Xu Bing 
Published: January 2017

AbstractHydrogels consisting of carboxylic acid groups and N‐isopropylacrylamide as pendants on their polymeric network usually exhibit volume expansion upon deprotonation or volume contraction when being heated. Demonstrated here is an anti‐intuitive case of a hydrogel containing multiple carboxylic acid groups at each crosslinking point in the polymeric network, which shrinks upon increasing pH from 1 to 7 at 37 °C or expands upon heating from 25 to 37 °C at pH 1. The unexpected volume change originates from the high percentage of the crosslinker in the polymers, as detected by solid‐state 13C NMR spectroscopy. In addition, the volume changes are thermally reversible. As the first example of the use of functional hyper‐crosslinkers to control the pH and thermal responses of nanogels, this work illustrates a new way to design soft materials with unusual behaviors.
Rational Design and Synthesis of Efficient Sunscreens To Boost the Solar Protection Factor
Authors: Losantos Raúl , Funes‐Ardoiz Ignacio , Aguilera José , Herrera‐Ceballos Enrique , García‐Iriepa Cristina , Campos Pedro J. , Sampedro Diego 
Published: January 2017

AbstractSkin cancer incidence has been increasing in the last decades, but most of the commercial formulations used as sunscreens are designed to protect only against solar erythema. Many of the active components present in sunscreens show critical weaknesses, such as low stability and toxicity. Thus, the development of more efficient components is an urgent health necessity and an attractive industrial target. We have rationally designed core moieties with increased photoprotective capacities and a new energy dissipation mechanism. Using these scaffolds, we have synthesized a series of compounds with tunable properties suitable for their use in sunscreens, and enhanced properties in terms of stability, light energy dissipation, and toxicity. Moreover, some representative compounds were included in final sunscreen formulations and a relevant solar protection factor boost was measured.
Cycloparaphenylenes and Their Catenanes: Complex Macrocycles Unveiled by Ion Mobility Mass Spectrometry
Authors: Zhang Wen , Abdulkarim Ali , Golling Florian E. , Räder Hans Joachim , Müllen Klaus 
Published: January 2017

AbstractThe insoluble product mixture obtained from cycloparaphenylene (CPP) synthesis from Suzuki coupling and reductive aromatization was analyzed. Traditional mass spectrometry suggests a homologous series of macrocycles with 12 to 84 phenylene units. Ion‐mobility mass spectrometry, however, unravels an unexpected complexity of isomers with identical chemical formula, but different topologies. Whereas macrocycles containing up to 30 phenylene units show only one structure, the homologue with 36 phenylene units forms at least four different isomers with significant molecular size differences. They can be assigned to catenanes composed of CPPs with 2×18 and 12+24 phenylene units together with the ordinary [36]CPP macrocycle. Most likely, a trefoil knot of the CPP with 36 moieties is also present. For the first time, catenanes can be elucidated in a simple reaction mixture by analyzing their ions in the gas phase, an analysis which lies beyond the scope of traditional analytical methods.
Modular Assembly of Spirocarbocyclic Scaffolds through Pd0‐Catalyzed Intermolecular Dearomatizing [2+2+1] Annulation of Bromonaphthols with Aryl Iodides and Alkynes
Authors: Zuo Zhijun , Wang Hui , Fan Liangxin , Liu Jingjing , Wang Yaoyu , Luan Xinjun 
Published: January 2017

AbstractA novel palladium(0)‐catalyzed dearomatizing [2+2+1] spiroannulation of 1‐bromo‐2‐naphthols with aryl iodides and alkynes was developed for the rapid assembly of spiro[indene‐1,1′‐naphthalen]‐2′‐ones. This three‐component cascade reaction was realized through consecutive Catellani‐type C−H activation, unsymmetrical biaryl coupling, alkyne migratory insertion, and arene dearomatization. The potential utility of our method is illustrated by the one‐step construction of the polycyclic skeletons of dalesconols A and B from alkyne‐tethered aryl iodides and 1‐bromo‐2‐naphthol.
Biocatalytic Total Synthesis of Ikarugamycin
Authors: Greunke Christian , Glöckle Anna , Antosch Janine , Gulder Tobias A. M. 
Published: January 2017

AbstractNature provides an inexhaustible diversity of small organic molecules with beautiful molecular architectures that have strong and selective inhibitory activities. However, this tremendous biomedical potential often remains inaccessible, as the structural complexity of natural products can render their synthetic preparation extremely challenging. This problem is addressable by harnessing the biocatalytic procedures evolved by nature. In this work, we present an enzymatic total synthesis of ikarugamycin. The use of an iterative PKS/NRPS machinery and two reductases has allowed the construction of 15 carbon–carbon and 2 carbon–nitrogen bonds in a biocatalytic one‐pot reaction. By scaling‐up this method we demonstrate the applicability of biocatalytic approaches for the ex vivo synthesis of complex natural products.
Protonation versus Oxonium Salt Formation: Basicity and Stability Tuning of Cyanoborate Anions
Authors: Kerpen Christoph , Sprenger Jan A. P. , Herkert Lorena , Schäfer Marius , Bischoff Lisa A. , Zeides Pierre , Grüne Matthias , Bertermann Rüdiger , Brede Franziska A. , Müller‐Buschbaum Klaus , Ignat'ev Nikolai V. , Finze Maik 
Published: January 2017

AbstractAnhydrous H[BH2(CN)2] crystallizes from acidic aqueous solutions of the dicyanodihydridoborate anion. The formation of H[BH2(CN)2] is surprising as the protonation of nitriles requires strongly acidic and anhydrous conditions but it can be rationalized based on theoretical data. In contrast, [BX(CN)3]− (X=H, F) gives the expected oxonium salts (H3O)[BX(CN)3] while (H3O)[BF2(CN)2]/H[BF2(CN)2] is unstable. H[BH2(CN)2] forms chains via N−H⋅⋅⋅N bonds in the solid state and melts at 54 °C. Solutions of H[BH2(CN)2] in the room‐temperature ionic liquid [EMIm][BH2(CN)2] contain the [(NC)H2BCN−H⋅⋅⋅NCBH2(CN)]− anion and are unusually stable, which enabled the study of selected spectroscopic and physical properties. [(NC)H2BCN−H⋅⋅⋅NCBH2(CN)]− slowly gives H2 and [(NC)H2BCN−BH(CN)2]−. The latter compound is a source of the free Lewis acid BH(CN)2, as shown by the generation of [BHF(CN)2]− and BH(CN)2⋅py.
Design of Artificial Glycosidases: Metallopeptides that Remove H Antigen from Human Erythrocytes
Authors: Yu Zhen , Cowan James Allan 
Published: January 2017

AbstractCatalysts that promote carbohydrate degradation have a wide range of potential applications, but the use of either enzyme glycosidases or small‐molecule catalysts in biological systems raises significant challenges. Herein, we demonstrate a novel strategy for the design of synthetic agents that mimic natural glycosidases and address current problems for biological use. This strategy is illustrated by application to the development of potential blood substitutes for the rare Bombay blood type that is characterized by a deficiency of H2 antigen. Metallopeptides with 16 to 20 amino acids were constructed as artificial fucosidases that exhibit selective carbohydrate cleavage reactivity toward l‐fucose over d‐glucose. Selective fucose cleavage from the H2‐antigen saccharide enables efficient removal of H2 antigen from erythrocytes and thereby accomplishes the conversion of regular human type‐O blood into a potential blood substitute for the rare Bombay blood type.
Alginate‐gelatin blend with embedded voids for controlled release applications
Authors: Banerjee Arindam , Patra Subhajit , Ganguly Somenath 
Published: January 2017

ABSTRACTAlginate gel is known for its potential use in the controlled release of drugs, and as a 3‐D structure for tissue harvesting. In this paper, the tuning of the performance of alginate gel by blending gelatin in the aqueous phase, and introducing bubbles in a regular alignment are discussed. Monodisperse bubbles in millimetre or submillimeter size were introduced into the aqueous suspension of the blend prior to gelation, using a novel fluidic arrangement. The CaCl2 solution, added as the crosslinker diffused into the lamella, forming a rigid structure of calcium alginate. The effective blending of gelatin in alginate provided benefits of both the biopolymers in the final product. The benefits are the excellent absorption capacity of alginate and the mechanical strength of gelatin in the blend. The self‐aligned voids enabled further tuning of absorption capacity and/or rate of release. Also, the presence of voids enhanced the elastomeric quality of the composite structure. The uptake of Vitamin B12 solution was measured gravimetrically, and the release in PBS buffer on a shaker was studied using UV‐vis spectrophotometer. For different loadings of void and gelatin, the absorption capacity, mechanical strength and the compression behavior were analysed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44787.
Surface modification and antimicrobial properties of cellulose nanocrystals
Authors: Bespalova Yulia , Kwon Dong , Vasanthan Nadarajah 
Published: January 2017

ABSTRACTA novel and simple surface modification of cellulose nanocrystals (CNC) was performed by chloroacetylation and subsequent reaction with tertiary amines to form quaternary ammonium modified CNCs. The acetylation of CNC and quaternary ammonium modified CNCs was confirmed using IR spectroscopy and solid state NMR spectroscopy. The 13C NMR spectrum of quaternary ammonium modified CNC showed several additional resonances ranging from 14.5 ppm to 58.0 ppm compared to 13C NMR spectrum of pure CNC, suggesting that alkyl chains have been added to the pure CNC. The disc diffusion method was used to evaluate the antimicrobial properties of quaternary ammonium modified CNCs. It was found that modified CNCs with alkyl chain longer than ten carbons are effective antimicrobial agents against Staphylococcus aureus and E. coli bacteria. These CNCs can be chemically modified to tailor the properties to improve dispersion in the polymer matrix. This will expand the application of CNC as a reinforcing material. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44789.
Continuous manufacturing of nanofiber yarn with the assistance of suction wind and rotating collection via needleless melt electrospinning
Authors: Ma Xiaolu , Zhang Liyan , Tan Jing , Qin Yongxin , Chen Hongbo , He Wanlin , Yang Weimin , Li Haoyi 
Published: January 2017

ABSTRACTNanofiber yarn was continuously manufactured by a needleless melt‐electrospinning method. The suction wind speed was the most important factor influencing the final fiber diameter and determining whether the fibers could be gathered into a well‐aligned strand. The twisting process of the yarn was performed by the adjustment of ratio of the speed of the collecting roller to the speed of the rotating disk. The results show that the higher the assisting suction wind speed was, the smaller the fiber diameter was. The smallest average fiber diameter of 440 nm was obtained at a suction wind speed of 30 m/s. Furthermore, the smaller the ratio of the speed of the collecting roller to the speed of the rotating disk was, the larger the twisting angle of the prepared yarn was. The largest twisting angle obtained in this study was 43 ° at the greatest ratio of the speed of the collecting roller to the speed of the rotating disk. The X‐ray diffraction results show that the alignment degree of the nanofiber twisting and the crystallinity increased with increasing twisting angle. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44820.
Improved mechanical strength of p(AAm) interpenetrating hydrogel network due to microgranular cellulose embedding
Authors: Sahiner Nurettin , Demirci Sahin 
Published: January 2017

ABSTRACTHere, polyacrylamide [p(AAm)]‐based hydrogels were synthesized via redox polymerization technique in the presence of various amounts of microgranular cellulose (MGCell) such as 0, 10, 25, 50, 100, and 150 mg MGCell/g. The synthesized p(AAm)‐MGCell interpenetrating hydrogels were characterized spectroscopically by FTIR, thermally by TGA analysis, and mechanically via dynamic mechanical measurements. Furthermore, the effect of the amount of MGCell in p(AAm) hydrogels on swelling% (S%) degree and mechanical strength was investigated. It was found that the S% was decreased from 727 ± 9 to 667 ± 6, 642 ± 8 and 619 ± 10, 568 ± 6 for p(AAm)‐MGCell interpenetrating network hydrogels containing 10, 50, 100, and 150 mg MGCell, respectively. On the other hand, the Young modulus of p(AAm)‐based hydrogels increased from 2.8 ± 0.2 kPa to 3.1 ± 0.03, 3.4 ± 0.1, 3.6 ± 0.3 and 4.3 ± 0.3 kPa with the incorporation of 10, 50, 100, and 150 mg MGCell into p(AAm) hydrogels. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44854.
H∞ Preview Control of A Class of Uncertain Discrete‐Time Systems
Authors: Li Li , Liao Fucheng , Deng Jiamei 
Published: January 2017

AbstractThis paper investigates the problem of H∞ preview tracking control with robust performance for uncertain discrete‐time systems. In order to avoid applying the difference operator to the time‐varying matrix, by taking advantage of the difference between the system state variables, input variables, and the corresponding auxiliary variables, instead of the usual difference between system states, an augmented error system including previewed information is constructed, which converts the tracking problem into a regulator problem. A sufficient condition based on the free‐weighting matrices technique and the Lyapunov stability theory is derived for the robust asymptotic stability of uncertain systems. Moreover, a state feedback control law with preview action design method is obtained via the linear matrix inequality approach. Based on these, a state observer for preview control systems is formulated. Previewable reference signals are fully utilized through reformulation of the output equation while designing the state observer. The proposed construction method of augmented error system is applicable to uncertain discrete‐time systems in which the uncertainties are general. Also an integrator is introduced to ensure the closed‐loop system tracking performance with no static error. The numerical results also show the effectiveness of the preview control law for uncertain systems in the paper.
Transition from oxcarbazepine to eslicarbazepine acetate: A single center study
Authors: Mäkinen Jussi , Rainesalo Sirpa , Peltola Jukka 
Published: January 2017

AbstractObjectivesThere is limited clinical evidence for comparison between oxcarbazepine (OXC) and eslicarbazepine acetate (ESL) in terms of tolerability, or how to execute the change from OXC to ESL. We report the process of transitioning patients with focal epilepsy from previous OXC treatment to ESL due to tolerability problems. The rationale for change from OXC is reported, and the outcome with respective to this rationale is analyzed in terms of tolerability and efficacy.Materials and MethodsThe subjects were transitioned overnight from OXC to ESL in a hospital inpatient setting. An evaluation of the effects of the transition was made after 1 and 3 months. All adverse events (AEs) were recorded following the transition period. Subjects were classified by outcome in terms of AEs.ResultsTwenty‐three subjects were transitioned from OXC to ESL. Fifteen patients OXC‐related AEs reduced significantly after transition. Particularly, most of (93%) the AEs presented in the morning resolved after transition to ESL. No patient had an increase in seizure frequency following the transition. The incidence of ESL‐related AEs was 39% at 1 month and 13% at 3 month follow‐up; however, all patients continued ESL throughout the study period.ConclusionsThis study demonstrates that patients suffering from OXC‐related AEs improve in terms of tolerability after a switch to ESL with maintaining seizure control. This improvement is more pronounced if the OXC‐related AEs are most evident following morning dosing of OXC. Transition can be safely executed in an outpatient setting.
Application of Biocatalysis to on‐DNA Carbohydrate Library Synthesis
Authors: Thomas Baptiste , Lu Xiaojie , Birmingham William R. , Huang Kun , Both Peter , Reyes Martinez Juana Elizabeth , Young Robert J. , Davie Christopher P. , Flitsch Sabine L. 
Published: January 2017

AbstractDNA‐encoded libraries are increasingly used for the discovery of bioactive lead compounds in high‐throughput screening programs against specific biological targets. Although a number of libraries are now available, they cover limited chemical space due to bias in ease of synthesis and the lack of chemical reactions that are compatible with DNA tagging. For example, compound libraries rarely contain complex biomolecules such as carbohydrates with high levels of functionality, stereochemistry, and hydrophilicity. By using biocatalysis in combination with chemical methods, we aimed to significantly expand chemical space and generate generic libraries with potentially better biocompatibility. For DNA‐encoded libraries, biocatalysis is particularly advantageous, as it is highly selective and can be performed in aqueous environments, which is an essential feature for this split‐and‐mix library technology. In this work, we demonstrated the application of biocatalysis for the on‐DNA synthesis of carbohydrate‐based libraries by using enzymatic oxidation and glycosylation in combination with traditional organic chemistry.