bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatially Resolved Insight into the Chemical and Electronic Structure of Solution‐Processed Perovskites—Why to (Not) Worry about Pinholes
Authors: Hartmann Claudia , Sadoughi Golnaz , Félix Roberto , Handick Evelyn , Klemm Hagen W. , Peschel Gina , Madej Ewa , Fuhrich Alexander B. , Liao Xiaxia , Raoux Simone , Abou‐Ras Daniel , Wargulski Dan , Schmidt Thomas , Wilks Regan G. , Snaith Henry , Bär Marcus
Published: January 2018

The unprecedented speed at which the performance of solar cells based on solution‐processed perovskite thin films has increased, in some ways, appears to violate conventional understanding of device optimization. The relatively poor coverage of the TiO2 electron transport layer by the absorber should cause shunting of the cell. This, however, is not the case. In this paper, it is attempted to explain this “discrepancy.” Insights into coverage, morphology, local elemental composition, and spatially resolved electronic structure of CH3NH3PbI(3−x)Clx perovskite absorbers wet‐chemically deposited on planar compact TiO2 electron transport material (ETM) are revealed. Microscopy images indicate an incomplete coverage of the ETM. Depending on the degree of coverage, a variation in iodine oxidation and metallic lead formation is found. With the electronic structure of the absorber and the ETM established experimentally and taking literature on the commonly used hole transport material spiro‐MeOTAD into account, it is revealed that excellent charge selectivity occurs at the interfaces between the absorber and both the hole and electron transport layers. It can also be surmised that, crucially, any direct interface between the TiO2 and spiro‐MeOTAD would be characterized by a large recombination barrier preventing shunts; to some extent minimizing the negative effects of absorber pinholes.
Ionic Liquid‐Assisted Preparation of Sb2S3/Reduced Graphene Oxide Nanocomposite for Sodium‐Ion Batteries
Authors: Pan Zhen‐Zhen , Yan Yang , Cui Nan , Xie Jin‐Cang , Zhang Ya‐Bo , Mu Wen‐Sheng , Hao Ce
Published: January 2018

Sodium‐ion batteries are regarded as a promising alternative to lithium ion batteries. However, their application is restricted by the low capacity and poor rate performance of existing anodes. Here, a stibnite/reduced graphene oxide nanocomposite is reported, fabricated by an ionic liquid‐assisted hydrothermal method, for sodium‐ion batteries. The obtained nanocomposite gives a high capacity of 687.7 mA h g−1 at 50 mA g−1 and an impressive rate performance. The promising electrochemical properties can be attributed to the uniformly distribution of Sb2S3 on reduced graphene oxide layers and the close contact between the two composites, which can be ensured by the addition of ionic liquid during the synthesizing process. This facile method shall pave the way for the production of other graphene‐based nanocomposite for sodium ion batteries and other energy storage systems.
Bioinspired Kirigami Fish‐Based Highly Stretched Wearable Biosensor for Human Biochemical–Physiological Hybrid Monitoring
Authors: Gao Bingbing , Elbaz Abdelrahman , He Zhenzhu , Xie Zhuoying , Xu Hua , Liu Songqin , Su Enben , Liu Hong , Gu Zhongze
Published: January 2018

The human quest for beauty is manifested in numerous body decoration fashions such as makeups, tattoos, and stickers. The ancient “kirigami” art offers a variety of choices for sticker‐type body beautification, whereby with simple cutting, complex networks potential use as microfluidic channels and stretchable materials can be fabricated. Inspired by the fish‐scale pattern and kirigami art, a fish‐like wearable biosensor is designed and fabricated. This highly stretchable, well‐aerated, disposable, and wearable fish sticker enables sweat collection, diagnostics, and motion monitoring. A structure of photonic crystals is integrated in the paper channels for fluorescence enhancement sensing of sweat lactic acid and urea, and a stretchable electronic paper network induced sensitive resistance changes during the movement. The sensor is amenable to a variety of applications, such as personal care and human–machine interaction. The combination of art and sensing also provides a pleasant‐looking solution for both health and beauty.
Polarization‐Sensitive Structural Colors with Hue‐and‐Saturation Tuning Based on All‐Dielectric Nanopixels
Authors: Yang Bo , Liu Wenwei , Li Zhancheng , Cheng Hua , Chen Shuqi , Tian Jianguo
Published: January 2018

Structural colors generated by the plasmonic resonance of metallic nanostructures, particularly aluminum, have been intensively studied in recent years. However, the inherent Ohmic loss and interband transitions in metals hinder the high efficiency and narrow bandwidth required for pure colors. Here, arrays of asymmetric titanium oxide elliptical nanopixels on a silica substrate are utilized to realize polarization‐sensitive structural colors with high saturation, high efficiency (more than 90%), and high resolution. Owing to Fano resonance resulting from the interference between the radiating waves of dipole resonances and directly reflected waves, perfect narrow reflected spectra can be formed with nearly ideal efficiency in the visible spectrum based on this all‐dielectric nanostructure. In particular, hue‐ and saturation‐tuned colors can be simultaneously obtained under two orthogonally polarized incident lights with apparent color contrast. Based on the superior properties of the titanium oxide metasurface, the proposed design strategy is anticipated to form a new paradigm for practical applications, such as high‐density optical data storage, nanoscale optical elements, sensing, security, and so on.
Polysaccharide‐Based Controlled Release Systems for Therapeutics Delivery and Tissue Engineering: From Bench to Bedside
Authors: Miao Tianxin , Wang Junqing , Zeng Yun , Liu Gang , Chen Xiaoyuan
Published: January 2018

Polysaccharides or polymeric carbohydrate molecules are long chains of monosaccharides that are linked by glycosidic bonds. The naturally based structural materials are widely applied in biomedical applications. This article covers four different types of polysaccharides (i.e., alginate, chitosan, hyaluronic acid, and dextran) and emphasizes their chemical modification, preparation approaches, preclinical studies, and clinical translations. Different cargo fabrication techniques are also presented in the third section. Recent progresses in preclinical applications are then discussed, including tissue engineering and treatment of diseases in both therapeutic and monitoring aspects. Finally, clinical translational studies with ongoing clinical trials are summarized and reviewed. The promise of new development in nanotechnology and polysaccharide chemistry helps clinical translation of polysaccharide‐based drug delivery systems.
High‐Efficiency Polymer Homo‐Tandem Solar Cells with Carbon Quantum‐Dot‐Doped Tunnel Junction Intermediate Layer
Authors: Kang Rakwon , Park Sujung , Jung Yun Kyung , Lim Dong Chan , Cha Myung Joo , Seo Jung Hwa , Cho Shinuk
Published: January 2018

The tunnel junction (TJ) intermediate connection layer (ICL), which is the most critical component for high‐efficient tandem solar cell, generally consists of hole conducting layer and polyethyleneimine (PEI) polyelectrolyte. However, because of the nonconducting feature of pristine PEI, photocurrent is open‐restricted in ICL even with a little thick PEI layer. Here, high‐efficiency homo‐tandem solar cells are demonstrated with enhanced efficiency by introducing carbon quantum dot (CQD)‐doped PEI on TJ–ICL. The CQD‐doped PEI provides substantial dynamic advantages in the operation of both single‐junction solar cells and homo‐tandem solar cells. The inclusion of CQDs in the PEI layer leads to improved electron extraction property in single‐junction solar cells and better series connection in tandem solar cells. The highest efficient solar cell with CQD‐doped PEI layer in between indium tin oxide (ITO) and photoactive layer exhibits a maximum power conversion efficiency (PCE) of 9.49%, which represents a value nearly 10% higher than those of solar cells with pristine PEI layer. In the case of tandem solar cells, the highest performing tandem solar cell fabricated with C‐dot‐doped PEI layer in ICL yields a PCE of 12.13%; this value represents an ≈15% increase in the efficiency compared with tandem solar cells with a pristine PEI layer.
Alkyl Chain Regiochemistry of Benzotriazole‐Based Donor Polymers Influencing Morphology and Performances of Non‐Fullerene Organic Solar Cells
Authors: Chen Shangshang , Zhang Lin , Ma Chao , Meng Dong , Zhang Jianquan , Zhang Guangye , Li Zhengke , Chow Philip C. Y. , Ma Wei , Wang Zhaohui , Wong Kam Sing , Ade Harald , Yan He
Published: January 2018

The effects of alkyl chain regiochemistry on the properties of donor polymers and performances of non‐fullerene organic solar cells are investigated. Two donor polymers (PfBTAZ and PfBTAZS) are compared that have nearly identical chemical structures except for the regiochemistry of alkyl chains. The optical properties and crystallinity of two polymers are nearly identical yet the PfBTAZ:O‐IDTBR blend exhibits nearly double domain size compared to the blend based on PfBTAZS:O‐IDTBR. To reveal the origins of the very different domain size of two blends, the morphology of neat polymer films is characterized, and it is found that PfBTAZ tends to aggregate into much larger polymer fibers without the presence of O‐IDTBR. This indicates that it is not the polymer:O‐IDTBR interactions but the intrinsic aggregation properties of two polymers that determine the morphology features of neat and blend films. The stronger aggregation tendency of PfBTAZ could be explained by its more co‐planar geometry of the polymer backbone arising from the different alkyl chain regiochemistry. Combined with the similar trend observed in another set of donor polymers (PTFB‐P and PTFB‐PS), the results provide an important understanding of the structure–property relationships that could guide the development of donor polymers for non‐fullerene organic solar cells.
Tunable and Efficient Tin Modified Nitrogen‐Doped Carbon Nanofibers for Electrochemical Reduction of Aqueous Carbon Dioxide
Authors: Zhao Yong , Liang Jiaojiao , Wang Caiyun , Ma Jianmin , Wallace Gordon G.
Published: January 2018

Efficient and selective earth‐abundant catalysts are highly desirable to drive the electrochemical conversion of CO2 into value‐added chemicals. In this work, a low‐cost Sn modified N‐doped carbon nanofiber hybrid catalyst is developed for switchable CO2 electroreduction in aqueous medium via a straightforward electrospinning technique coupled with a pyrolysis process. The electrocatalytic performance can be tuned by the structure of Sn species on the N‐doped carbon nanofibers. Sn nanoparticles drive efficient formate formation with a high current density of 11 mA cm−2 and a faradaic efficiency of 62% at a moderate overpotential of 690 mV. Atomically dispersed Sn species promote conversion of CO2 to CO with a high faradaic efficiency of 91% at a low overpotential of 490 mV. The interaction between Sn species and pyridinic‐N may play an important role in tuning the catalytic activity and selectivity of these two materials.
Scavenging Wind Energy by Triboelectric Nanogenerators
Authors: Chen Bo , Yang Ya , Wang Zhong Lin
Published: January 2018

To meet future needs for clean and sustainable energy, tremendous progress has been achieved in development for scavenging wind energy. The most classical approach is to use the electromagnetic effect based wind turbine with a diameter of larger than 50 m and a weight of larger than 50 ton, and each of them could cost more than $0.5 M, which can only be installed in remote areas. Alternatively, triboelectric nanogenerators based on coupling of contact‐electrification and electrostatic induction effects have been utilized to scavenge wind energy, which takes the advantages of high voltage, low cost, and small size. Here, the development of a wind‐driven triboelectric nanogenerator by focusing on triboelectric materials optimization, structure improvement, and hybridization with other types of energy harvesting techniques is reviewed. Moreover, the major applications are summarized and the challenges that are needed to be addressed and development direction for scavenging wind energy in future are highlighted.
Recent Progress in Ternary Organic Solar Cells Based on Nonfullerene Acceptors
Authors: Yu Runnan , Yao Huifeng , Hou Jianhui
Published: January 2018

The use of a ternary component is a facile and effective method to further improve the device performances of binary organic solar cells (OSCs) comprising one donor and one acceptor. Recently, the rapid progress of highly efficient nonfullerene acceptor materials has offered a new opportunity for studying ternary OSCs because of the flexibility of ternary components, and the photovoltaic performance of ternary OSCs has been promoted quickly. In this research news article, some strategies for materials selection of the ternary components are concisely summarized and the recent progress in ternary OCSs based on nonfullerene acceptors, and the challenges and perspectives of ternary OSCs are also presented.
Nonspherical particles in a pseudo‐2D fluidized bed: Experimental study
Authors: Mahajan Vinay V. , Padding Johan T. , Nijssen Tim M. J. , Buist Kay A. , Kuipers J. A. M.
Published: January 2018

Fluidization is widely used in industries and has been extensively studied, both experimentally and theoretically, in the past. However, most of these studies focus on spherical particles while in practice granules are rarely spherical. Particle shape can have a significant effect on fluidization characteristics. It is therefore important to study the effect of particle shape on fluidization behavior in detail. In this study, experiments in pseudo‐2D fluidized beds are used to characterize the fluidization of spherocylindrical (rod‐like) Geldart D particles of aspect ratio 4. Pressure drop and optical measurement methods (Digital Image Analysis, Particle Image Velocimetry, Particle Tracking Velocimetry) are employed to measure bed height, particle orientation, particle circulation, stacking, and coordination number. The commonly used correlations to determine the pressure drop across a bed of nonspherical particles are compared to experiments. Experimental observations and measurements have shown that rod‐like particles are prone to interlocking and channeling behavior. Well above the minimum fluidization velocity, vigorous bubbling fluidization is observed, with groups of interlocked particles moving upwards, breaking up, being thrown high in the freeboard region and slowly raining down as dispersed phase. At high flowrates, a circulation pattern develops with particles moving up through the center and down at the walls. Particles tend to orient themselves along the flow direction. © 2018 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 64: 1573–1590, 2018
Nonhomogeneous flow of micellar solutions: A kinetic—network theory approach
Authors: García‐Sandoval J. Paulo , Martín del Campo A. , Bautista F. , Manero O. , Puig Jorge E.
Published: January 2018

The rheological behavior of micellar solutions is analyzed under nonhomogeneous velocity and stress flow conditions. The framework is based on the extended irreversible thermodynamics and the transient network formulation coupled to the underlying kinetics embodying two relevant processes: formation of wormlike chains from a free micellar solution through a thermally activated process and their flow induced degradation. The second kinetic process consists in the formation of entanglements from the free wormlike chains and their flow‐induced breakage. These processes are modeled in a coupled kinetic scheme constituted by a set of reversible kinetic equations describing the evolution in average of the three microstates (free short rod‐like micelles, free wormlike chains, and entangled wormlike chains) that reflect the complexity of macromolecular interactions. The predictions of the shear stress and first normal stress difference as a function of shear‐rate under banded flow are in good agreement with experimental data. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2277–2292, 2018
Realizing effectiveness across continents with hydroxyurea: Enrollment and baseline characteristics of the multicenter REACH study in Sub‐Saharan Africa
Authors: McGann Patrick T. , Williams Thomas N. , Olupot‐Olupot Peter , Tomlinson George A. , Lane Adam , Luís Reis da Fonseca José , Kitenge Robert , Mochamah George , Wabwire Ham , Stuber Susan , Howard Thad A. , McElhinney Kathryn , Aygun Banu , Latham Teresa , Santos Brígida , Tshilolo Léon , Ware Russell E. ,   for the REACH Investigators
Published: January 2018

Despite its well‐described safety and efficacy in the treatment of sickle cell anemia (SCA) in high‐income settings, hydroxyurea remains largely unavailable in sub‐Saharan Africa, where more than 75% of annual SCA births occur and many comorbidities exist. Realizing Effectiveness Across Continents with Hydroxyurea (REACH, ClinicalTrials.gov NCT01966731) is a prospective, Phase I/II open‐label trial of hydroxyurea designed to evaluate the feasibility, safety, and benefits of hydroxyurea treatment for children with SCA in four sub‐Saharan African countries. Following comprehensive training of local research teams, REACH was approved by local Ethics Committees and achieved full enrollment ahead of projections with 635 participants enrolled over a 30‐month period, despite half of families living >12 km from their clinical site. At enrollment, study participants (age 5.4 ± 2.4 years) had substantial morbidity, including a history of vaso‐occlusive pain (98%), transfusion (68%), malaria (85%), and stroke (6%). Significant differences in laboratory characteristics were noted across sites, with lower hemoglobin concentrations (P < .01) in Angola (7.2 ± 1.0 g/dL) and the DRC (7.0 ± 0.9 g/dL) compared to Kenya (7.4 ± 1.1 g/dL) and Uganda (7.5 ± 1.1 g/dL). Analysis of known genetic modifiers of SCA demonstrated a high frequency of α‐thalassemia (58.4% with at least a single α‐globin gene deletion) and G6PD deficiency (19.7% of males and 2.4% of females) across sites. The CAR β‐globin haplotype was present in 99% of participants. The full enrollment to REACH confirms the feasibility of conducting high‐quality SCA research in Africa; this study will provide vital information to guide safe and effective dosing of hydroxyurea for children with SCA living in Africa.
Palladium‐Catalyzed Direct Oxidative Esterification of Indoles at the C3 Position: A Novel Prospect for C(sp2)−H Acyloxylation
Authors: Song Jian , Cui Jie , Liang Hanbing , Liu Qing , Dong Yunhui , Liu Hui
Published: January 2018

An efficient palladium‐catalyzed direct oxidative esterification reaction of indoles with both aliphatic and aromatic carboxylic acids is reported. The use of Ag2CO3 is crucial to this transformation, as it functions as both a base and an oxidant for the regeneration of the palladium(II) catalyst. This methodology represents a novel prospect for C(sp2)−H acyloxylation and will promote interest in direct C(sp2)−H esterification.
Fiber type composition of epaxial muscles is geared toward facilitating rapid spinal extension in the leaper Galago senegalensis
Authors: Huq Emranul , Taylor Andrea B. , Su Zuowei , Wall Christine E.
Published: January 2018

Objectives

We hypothesized that the vertical leaper Galago senegalensis will have epaxial extensor muscles with a fast fiber phenotype to facilitate rapid spinal extension during leaping in comparison to the slow‐moving quadruped Nycticebus coucang. To test this, we determined the percentage of fiber cross‐sectional area (%CSA) devoted to Type 2 fibers in epaxial muscles of G. senegalensis compared to those of N. coucang.

Materials and methods

Immunohistochemistry was used to identify Type 1, Type 2, and hybrid fibers in iliocostalis, longissimus, and multifidus muscles of G. senegalensis (n = 3) and N. coucang (n = 3). Serial muscle sections were used to estimate and compare proportions, cross‐sectional areas (CSAs), and %CSAs of Type 1, Type 2, and hybrid fibers between species.

Results

Epaxial muscles of G. senegalensis were comprised predominantly of Type 2 fibers with large CSAs (%CSA range ≈ 83–94%; range of mean CSA = 1,218–1,586 μm2). N. coucang epaxial muscles were comprised predominantly Type 1 fibers with large CSAs (%CSA range ≈ 69–77%; range of mean CSA = 983–1,220 μm2).

Discussion

The predominance of Type 2 fibers in G. senegalensis epaxial muscles facilitates rapid muscle excursion and spinal extension during leaping, and is consistent with their relatively long muscle fibers. The predominance of Type 1 fibers in N. coucang epaxial muscles may aid in maintaining stable postures during bridging and cantilevering behaviors characteristic of slow‐climbing. These histochemical characteristics highlight the major divergent locomotor repertoires of G. senegalensis and N. coucang.
Are multiple sinus cultures necessary during sinus surgery for chronic rhinosinusitis?
Authors: Miller Craig , Davis Greg E.
Published: January 2018

Background

Multiple cultures are commonly obtained from different sinuses where purulence is encountered during endoscopic sinus surgery (ESS). This brings into question the utility and necessity of obtaining multiple cultures. The purpose of this study was to evaluate if multiple cultures obtained during a single case is informative in finding additional pathogens or if it is a redundant, cost‐increasing practice. We hypothesized that multiple sinus cultures are necessary to identify the pathogens responsible for an individual's sinus disease. We seek to add information on the utility of performing multiple sinus cultures from a patient care and a health economics standpoint.

Methods

This study was a retrospective review of a single rhinologist's surgical database from 2008 to 2016. Patients that underwent ESS for chronic rhinosinusitis (CRS) and had multiple cultures obtained during surgery were included. Culture difference was recorded as a discrepancy of an infectious pathogen between cultures.

Results

We identified 231 patients with multiple sinus cultures. Of those, 39.4% had a difference of pathogens noted on culture between different sinuses. Only 5% of the cohort received clinically relevant benefit from the second culture obtained in regard to a change in antibiotics.

Conclusion

In this retrospective review we showed that, for the practitioner who obtains sinus cultures intraoperatively, limiting this practice to a single culture rather than multiple is cost‐effective and sufficient for identifying the pathogen to be treated. This study, and the resultant change in practice, has the potential to reduce healthcare costs associated with the surgical care of the patient with CRS.
Signalverstärkung durch reversiblen Austausch (SABRE): von der Entdeckung zur diagnostischen Anwendung
Authors: Rayner Peter J. , Duckett Simon B.
Published: January 2018

Signalverstärkung durch reversiblen Austausch (SABRE) wandelt typischerweise schwache Kernresonanz‐Aussagen in starke Signale um, wodurch sonst nicht durchführbare Messungen möglich werden. Aufgrund ihrer Geschwindigkeit und Einfachheit hat die Methode erhebliche Beliebtheit gewonnen. Dieser Kurzaufsatz beschreibt die Entwicklung von SABRE ausgehend von der ursprünglichen Hyperpolarisation von Pyridin im Jahr 2009 bis zu dem Punkt, bei dem 50‐prozentige 1H‐Polarisationsgrade für ein Dideuterionicotinat erzielt wurden, womit ein Schlüsselschritt des Wegs zu einer denkbaren klinischen Anwendung erreicht war. Einfache Wege zur hocheffizienten 15N‐Hyperpolarisation und zur Generierung langlebiger hyperpolarisierter magnetischer Zustände werden aufgezeigt. Abschließend beschreiben wir, wie das kürzlich berichtete SABRE‐RELAY‐Verfahren Parawasserstoff einen Weg bietet, einen viel größeren Umfang molekularer Baugruppen wie Amide, Alkohole, Carbonsäuren und Phosphate zu hyperpolarisieren, als dies früher für möglich gehalten wurde. Schon heute ist vorauszusehen, dass SABRE aufgrund dieser gebündelten Entwicklungen erhebliche Auswirkungen sowohl auf die chemische Analyse als auch auf die Diagnose von Krankheiten haben wird.
Near‐Infrared Fluorescent Molecular Probe for Sensitive Imaging of Keloid
Authors: Miao Qingqing , Yeo David C. , Wiraja Christian , Zhang Jianjian , Ning Xiaoyu , Xu Chenjie , Pu Kanyi
Published: January 2018

Early detection of skin diseases is imperative for their effective treatment. However, fluorescence molecular probes that allow this are rare. The first activatable near‐infrared (NIR) fluorescent molecular probe is reported for sensitive imaging of keloid cells, skin cells from abnormal scar fibrous lesions. As keloid cells have high expression levels of fibroblast activation protein‐alpha (FAPα), the probe (FNP1) is designed to have a caged NIR dye and a FAPα‐cleavable peptide substrate linked by a self‐immolative segment. FNP1 can quickly and specifically turn on its fluorescence at 710 nm by 45‐fold in the presence of FAPα, allowing it to effectively recognize keloid cells from normal skin cells. Integration of FNP1 with a simple microneedle‐assisted topical application enables sensitive detection of keloid cells in metabolically‐active human skin tissue with a theoretical limit of detection down to 20 000 cells.
Total Synthesis of Aurofusarin: Studies on the Atropisomeric Stability of Bis‐Naphthoquinones
Authors: Qi Chao , Wang Wenyu , Reichl Kyle D. , McNeely James , Porco John A.
Published: January 2018

An efficient annulation involving pyrone addition to a quinone and Dieckmann condensation was developed for rapid assembly of a γ‐naphthopyrone monomeric precursor to the bis‐naphthoquinone natural product aurofusarin. Dimerization was achieved through PdII‐catalyzed dehydrogenative coupling. Further studies employing asymmetric nucleophilic epoxidation indicate that the atropisomers of aurofusarin and derivatives are not configurationally stable at ambient temperature.
Easy‐to‐Attach/Detach Solubilizing‐Tag‐Aided Chemical Synthesis of an Aggregative Capsid Protein
Authors: Tsuda Shugo , Mochizuki Masayoshi , Ishiba Hiroyuki , Yoshizawa‐Kumagaye Kumiko , Nishio Hideki , Oishi Shinya , Yoshiya Taku
Published: January 2018

A solubilizing Trt‐K10 tag was developed for the effective chemical preparation of peptides/proteins with low solubility. The Trt‐K10 tag comprises a hydrophilic oligo‐Lys sequence and a trityl anchor, and can be selectively introduced to a side chain thiol of Cys of deprotected peptides/proteins with a trityl alcohol‐type introducing reagent Trt(OH)‐K10 under acidic conditions. Significantly, the ligation product in the reaction mixture of a thiol‐additive‐free native chemical ligation can be modified directly in a one‐pot manner to facilitate the isolation of the product by high‐performance liquid chromatography. Finally, the Trt‐K10 tag can be readily removed with a standard trifluoroacetic acid cocktail. Using this easy‐to‐attach/detach tag‐aided method, a hepatitis B virus capsid protein that is usually difficult to handle was synthesized successfully.
Ein aktiver und stabiler Cobaltkatalysator für die Sauerstoffentwicklungsreaktion: Polymerisation einer ionischen Flüssigkeit
Authors: Ding Yuxiao , Klyushin Alexander , Huang Xing , Jones Travis , Teschner Detre , Girgsdies Frank , Rodenas Tania , Schlögl Robert , Heumann Saskia
Published: January 2018

Inspiriert durch die katalytischen Eigenschaften von Single‐site‐Katalysatoren und der erhöhten Leistungsfähigkeit von Metallkatalysatoren durch ionische Flüssigkeiten wurde eine Methode zur gezielten und skalierbaren Platzierung von einzelnen Cobaltatomen auf Kohlenstoffnanoröhrenoberflächen mithilfe einer polymerisierten ionischen Flüssigkeit entwickelt. Durch eine ionische Flüssigkeit wurden einzelne, fein verteilte Cobaltionen koordiniert und als heterogener Katalysator für die Sauerstoffententwicklungsreaktion (OER) genutzt. Die erhaltenen Daten zeigen eine hohe Aktivität bei gleichzeitig vorhandener Stabilität.
Molekulare Brandbekämpfung – wie moderne Phosphorchemie zur Lösung der Flammschutzaufgabe beitragen kann
Authors: Velencoso Maria M. , Battig Alexander , Markwart Jens C. , Schartel Bernhard , Wurm Frederik R.
Published: January 2018

Materialien aus Kunststoffen sind allgegenwärtig im täglichen Leben und haben ein hohes Brandrisiko. Die nachhaltige Entwicklung effizienter Flammschutzmittel ist essenziell, um die Sicherheit unserer Güter und der Bevölkerung vor zufällig auftretenden Bränden zu gewährleisten. Phosphor, ein vielseitiges und wirksames Element für den Einsatz in Flammschutzmitteln, hat das Potenzial, die heute noch weit verbreiteten halogenierten Verbindungen abzulösen: Die verschiedenen Formulierungen phosphorhaltiger Flammschutzmittel beruhen auf einer Vielzahl von Wirkmechanismen und Implementierungen, als Additive oder als reaktive flammhemmende Verbindungen. Phosphorflammschutzmittel können während eines Brandes sowohl in der Gas‐ als auch in der kondensierten Phase aktiv sein. Dieser Aufsatz fasst die aktuelle Phosphorchemie zur Verringerung der Entflammbarkeit von Polymeren zusammen und stellt potenziell nachhaltige, effiziente und sichere phosphorbasierte Flammschutzmittel aus erneuerbaren Quellen für zukünftige Anwendungen vor.
Disilenylsilylen‐Reaktivität eines Cyclotrisilens
Authors: Zhao Hui , Leszczyńska Kinga , Klemmer Lukas , Huch Volker , Zimmer Michael , Scheschkewitz David
Published: January 2018

Die hoch reaktiven Silicium‐Kongenere des Cyclopropens, die Cyclotrisilene (c‐Si3R4), reagieren typischerweise unter π‐Addition an ihre Si=Si‐Doppelbindung oder unter σ‐Insertion in eine ihrer Si‐Si‐Einfachbindungen. Im Gegensatz dazu führt die Behandlung von c‐Si3Tip4 (Tip=2,4,6‐iPr3C6H2) mit Styrol und Benzil zur Ringöffnung des Dreirings zum formalen [1+2]‐ bzw. [1+4]‐Cycloadditionsprodukt des isomeren Disilenysilylens mit der C=C‐Bindung bzw. dem Diketon. Bei erhöhten Temperaturen setzt das [1+2]‐Additionsprodukt Styrol frei, das in einer [2+2]‐Cycloaddition mit c‐Si3Tip4 zu der thermodynamisch stabileren Hausan‐Spezies reagiert.
Enantioselective Desymmetrization of Cyclobutanones Enabled by Synergistic Palladium/Enamine Catalysis
Authors: Wang Meng , Chen Jun , Chen Zongjia , Zhong Changxu , Lu Ping
Published: January 2018

The enantioselective intramolecular α‐arylation of cyclobutanones has been established by combining palladium and enamine catalyst systems. Two different enantioselective control strategies have been developed for cyclobutanone substrates bearing O‐ or N‐tethered aryl bromides. Further synthetic applications are also reported.
Spectroscopic Characterization of a [C−F−C]+ Fluoronium Ion in Solution
Authors: Pitts Cody Ross , Holl Maxwell Gargiulo , Lectka Thomas
Published: January 2018

We report the first spectroscopic evidence for a [C−F−C]+ fluoronium ion in solution. Extensive NMR studies (19F, 1H, 13C) characterize a symmetric cage‐like species in which fluorine exhibits substantial covalent bonding to each of the two carbon atoms involved in the three‐center interaction. Experimental NMR data comport well with calculated values to lend credence to the structural assignment. As the culminating experiment, a Saunders isotopic perturbation test confirmed the symmetric structure. Congruent with the trend in other types of onium ions, the calculated charge at fluorine moves in a more positive (less negative) direction from the neutral. It is this important trend that explains in part the extraordinary historical difficulty in making theoretical predictions of fluoronium ions come true in solution, and why it takes fluorine captured in a cage to produce, finally, a stable ion and complete the historical arc of the organic halonium ion story.
Palladium/Copper Dual Catalysis for the Cross‐Coupling of Aryl(trialkyl)silanes with Aryl Bromides
Authors: Komiyama Takeshi , Minami Yasunori , Furuya Yuki , Hiyama Tamejiro
Published: January 2018

Whereas aryl(trialkyl)silanes are considered to be ideal organometallic reagents for cross‐coupling reactions owing to their stability, low toxicity, solubility, and easy accessibility, they are generally inert under typical cross‐coupling conditions. Disclosed herein is a palladium/copper catalytic system that enables the cross‐coupling of trimethyl, triethyl, tert‐butyldimethyl, and triisopropyl aryl silanes with aryl bromides. This process is applicable to the sequential C−H and C−Si bond arylation of thiophenes and the synthesis of poly(thiophene–fluorene)s.
Visible‐Light‐Mediated Decarboxylative Radical Additions to Vinyl Boronic Esters: Rapid Access to γ‐Amino Boronic Esters
Authors: Noble Adam , Mega Riccardo S. , Pflästerer Daniel , Myers Eddie L. , Aggarwal Varinder K.
Published: January 2018

The synthesis of alkyl boronic esters by direct decarboxylative radical addition of carboxylic acids to vinyl boronic esters is described. The reaction proceeds under mild photoredox catalysis and involves an unprecedented single‐electron reduction of an α‐boryl radical intermediate to the corresponding anion. The reaction is amenable to a diverse range of substrates, including α‐amino, α‐oxy, and alkyl carboxylic acids, thus providing a novel method to rapidly access boron‐containing molecules of potential biological importance.
N‐Substituted Hydrazones by Manganese‐Catalyzed Coupling of Alcohols with Hydrazine: Borrowing Hydrogen and Acceptorless Dehydrogenation in One System
Authors: Das Uttam Kumar , Ben‐David Yehoshoa , Diskin‐Posner Yael , Milstein David
Published: January 2018

An unprecedented one‐step synthesis of N‐substituted hydrazones by coupling of alcohols with hydrazine is reported. This partial hydrogen‐borrowing reaction is catalyzed by a new manganese pincer complex under mild reaction conditions, thus liberating water and dihydrogen as the only byproducts. Mechanistic insight, based on the observation of intermediates, is provided.
An Oxygen‐Tolerant PET‐RAFT Polymerization for Screening Structure–Activity Relationships
Authors: Gormley Adam J. , Yeow Jonathan , Ng Gervase , Conway Órla , Boyer Cyrille , Chapman Robert
Published: January 2018

The complexity of polymer–protein interactions makes rational design of the best polymer architecture for any given biointerface extremely challenging, and the high throughput synthesis and screening of polymers has emerged as an attractive alternative. A porphyrin‐catalysed photoinduced electron/energy transfer–reversible addition‐fragmentation chain‐transfer (PET‐RAFT) polymerisation was adapted to enable high throughput synthesis of complex polymer architectures in dimethyl sulfoxide (DMSO) on low‐volume well plates in the presence of air. The polymerisation system shows remarkable oxygen tolerance, and excellent control of functional 3‐ and 4‐arm star polymers. We then apply this method to investigate the effect of polymer structure on protein binding, in this case to the lectin concanavalin A (ConA). Such an approach could be applied to screen the structure–activity relationships for any number of polymer–protein interactions.
Molecular Firefighting—How Modern Phosphorus Chemistry Can Help Solve the Challenge of Flame Retardancy
Authors: Velencoso Maria M. , Battig Alexander , Markwart Jens C. , Schartel Bernhard , Wurm Frederik R.
Published: January 2018

The ubiquity of polymeric materials in daily life comes with an increased fire risk, and sustained research into efficient flame retardants is key to ensuring the safety of the populace and material goods from accidental fires. Phosphorus, a versatile and effective element for use in flame retardants, has the potential to supersede the halogenated variants that are still widely used today: current formulations employ a variety of modes of action and methods of implementation, as additives or as reactants, to solve the task of developing flame‐retarding polymeric materials. Phosphorus‐based flame retardants can act in both the gas and condensed phase during a fire. This Review investigates how current phosphorus chemistry helps in reducing the flammability of polymers, and addresses the future of sustainable, efficient, and safe phosphorus‐based flame‐retardants from renewable sources.
Cobalt‐Catalyzed Coupling of Benzoic Acid C−H Bonds with Alkynes, Styrenes, and 1,3‐Dienes
Authors: Nguyen Tung Thanh , Grigorjeva Liene , Daugulis Olafs
Published: January 2018

A method for cobalt‐catalyzed, carboxylate‐directed functionalization of arene C−H bonds is reported. Alkynes, styrenes, and 1,3‐dienes can be coupled with benzoic acids to provide cyclic products in good yields. The reactions proceed in the presence of a cobalt(II) hexafluoroacetylacetonate catalyst, (TMS)2NH base, Ce(SO4)2 cooxidant, and oxygen oxidant.
Dual Ligand‐Enabled Nondirected C−H Olefination of Arenes
Authors: Chen Hao , Wedi Philipp , Meyer Tim , Tavakoli Ghazal , van Gemmeren Manuel
Published: January 2018

The application of the Pd‐catalyzed oxidative C−H olefination of arenes, also known as the Fujiwara–Moritani reaction, has traditionally been limited by the requirement for directing groups on the substrate or the need to use the arene in large excess, typically as a (co)solvent. Herein the development of a catalytic system is described that, through the combined action of two complementary ligands, makes it possible to use directing‐group‐free arenes as limiting reagents for the first time. The reactions proceed under a combination of both steric and electronic control and enable the application of this powerful reaction to valuable arenes, which cannot be utilized in excess.
Active Molybdenum‐Based Anode for Dehydrogenative Coupling Reactions
Authors: Beil Sebastian B. , Müller Timo , Sillart Sydney B. , Franzmann Peter , Bomm Alexander , Holtkamp Michael , Karst Uwe , Schade Wolfgang , Waldvogel Siegfried R.
Published: January 2018

A new and powerful active anode system that can be operated in 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) has been discovered. In HFIP the molybdenum anode forms a compact, conductive, and electroactive layer of higher‐valent molybdenum species. This system can replace powerful but stoichiometrically required MoV reagents for the dehydrogenative coupling of aryls. This electrolytic reaction is more sustainable and allows the conversion of a broad scope of activated arenes.
Modifying the Steric Properties in the Second Coordination Sphere of Designed Peptides Leads to Enhancement of Nitrite Reductase Activity
Authors: Koebke Karl J. , Yu Fangting , Salerno Elvin , Van Stappen Casey , Tebo Alison G. , Penner‐Hahn James E. , Pecoraro Vincent L.
Published: January 2018

Protein design is a useful strategy to interrogate the protein structure‐function relationship. We demonstrate using a highly modular 3‐stranded coiled coil (TRI‐peptide system) that a functional type 2 copper center exhibiting copper nitrite reductase (NiR) activity exhibits the highest homogeneous catalytic efficiency under aqueous conditions for the reduction of nitrite to NO and H2O. Modification of the amino acids in the second coordination sphere of the copper center increases the nitrite reductase activity up to 75‐fold compared to previously reported systems. We find also that steric bulk can be used to enforce a three‐coordinate CuI in a site, which tends toward two‐coordination with decreased steric bulk. This study demonstrates the importance of the second coordination sphere environment both for controlling metal‐center ligation and enhancing the catalytic efficiency of metalloenzymes and their analogues.
Alkaline–Acid Zn–H2O Fuel Cell for the Simultaneous Generation of Hydrogen and Electricity
Authors: Cai Pingwei , Li Yan , Wang Genxiang , Wen Zhenhai
Published: January 2018

An alkaline–acid Zn–H2O fuel cell is proposed for the simultaneous generation of electricity with an open circuit voltage of about 1.25 V and production of H2 with almost 100 % Faradic efficiency. We demonstrate that, as a result of harvesting energy from both electrochemical neutralization and electrochemical Zn oxidation, the as‐developed hybrid cell can deliver a power density of up to 80 mW cm−2 and an energy density of 934 Wh kg−1 and maintain long‐term stability for H2 production with an output voltage of 1.16 V at a current density of 10 mA cm−2.
Study of the chemical structure and the microbial effect of iron(III) metal ions with four consecutive generations of quinolones in a nanometric form for the purpose of increasing the efficacy of antibacterial and antifungal drugs
Authors: Refat Moamen S. , El‐Sayed Mohamed Y. , Hassan Reham F.
Published: January 2018

A new series of iron(III) complexes with different fourth generation of quinolone drugs of the type [Fe(L)n(Cl)x]⋅yH2O ((1) L: nalidixic acid, n = 3, x = 3, y = 3; (2) L: oxolonic acid, n = 3, x = 3, y = 0; (3) L: pipemidic acid, n = 3, x = 3, y = 2; (4) L: lomefloxacin, n = 3, x = 3, y = 0; (5) L: pefloxacin mesylate, n = 3, x = 3, y = 2; (6) L: levofloxacin, n = 3, x = 3, y = 6) were synthesized and identified using microanalysis, Fourier transform infrared spectroscopy, conductance data, effective magnetic moments and electronic UV–visible spectra. In these six complexes, the quinolone drug chelates act in a unidentate manner via nitrogen atom of pyridone/piperazyl moiety. Electronic spectroscopic data are in agreement with an octahedral geometrical structure. Thermal degradation analyses in nitrogen gas were used to investigate the number and location of water molecules. The thermal decomposition process is completed in 3−5 steps, the first step being responsible for loss of uncoordinated water molecules and the steady state of all complexes occurs at around 500 °C with oxide forms as residual products. The stabilities of iron(III) complexes 1–6 were studied in terms of activation energy E*, entropy ΔS*, enthalpy ΔH* and Gibbs free energy ΔG* that were estimated using Coats–Redfern and Horowitz–Metzger non‐isothermal methods. Molecular docking was used to predict the binding between some of the quinolone drugs and the receptor of prostate cancer 2q7k hormone.
Shear test method for and mechanical characteristics of short basalt fiber reinforced polymer composite materials
Authors: Chen Jinxiang , Tuo Wanyong , Wan Chunfeng , Zhang Xiaoming
Published: January 2018

In this work, an experimental study was performed to investigate the shearing mechanical properties of short basalt fiber‐reinforced polymer composite materials (SBFRP), and an optimized test method was developed. The following findings were obtained: (1) The optimized V‐notched rail shear device and test method are reliable and valid, enabling the effective shear testing of samples similar to those tested in this study in the future. (2) The shearing failure cracks of SBFRPs can be classified into three types, namely, main cracks, coupling cracks, and micro‐cracks. The micro‐cracks, which originate from micro‐slippage at the interfaces between the short fibers and the epoxy resin, initiate prior to the main cracks. (3) The existence of a critical value of the fiber volume fraction is proposed, above which a sample possesses a nonlinear deformation capacity by virtue of the initial micro‐slippage at the fiber/matrix interfaces. Furthermore, a higher fiber volume fraction gives rise to a stronger nonlinear deformation capacity. (4) The shearing mechanical properties and other basic material attributes of SBFRPs with a fiber length of 3 mm are presented, thereby establishing a foundation for the theoretical study, finite‐element analysis, and application and dissemination of SBFRPs. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46078.
Simple method for preparation of thermally expandable microspheres of PMMA encapsulating NaHCO3via thermally induced phase separation
Authors: Zhou Shuqian , Li Zheng , Zhou Zhengfa , Xu Weibing , Ma Haihong , Ren Fengmei
Published: January 2018

Thermally expandable microspheres (TEMs) employing poly(methyl methacrylate) (PMMA) as shell and sodium bicarbonate (NaHCO3) as core were prepared by a simple method of thermally induced phase separation (TIPS). The addition of NaHCO3improved the foaming properties of TEMs. The effects of preparation parameters on the morphology, amount of encapsulated NaHCO3, and foaming properties of TEMs were studied; the parameters investigated included the quench rate, the molecular weight (Mw) and amount of PMMA, and the amount of NaHCO3. The results show that when 0.5 g of PMMA 50k, 3 g of NaHCO3, and 50 g of ethanol were used, with quenching temperature at 0 °C, the TEMs were fully spherical and the maximum expansion volume of TEMs was about 3.8 times the original volume. The expansion volume of TEMs increased with increasing amount of encapsulated NaHCO3, and the foaming onset temperature and temperature of complete bursting of TEMs were related to theMwof PMMA. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46179.
Aloe vera gel influence on the micellization behavior of copolymer Pluronic F127: A potential photosensitizer carrier for topical application
Authors: Dantas Silva Luis Alberto Soto , da Cruz de Jesus Rafael Leone , Fiuza‐Junior Raildo Alves , Andrade Heloysa Martins Carvalho , Rigoli Isabel Cristina , de Assunção Rosana Maria Nascimento , Barichello José Mario , de Lima Renata Galvão
Published: January 2018

This work describes the influence of aloe vera gel on Pluronic F127 triblock copolymer (F127) micellization behavior. Aloe vera gel was obtained from aloe vera mucilage found in leaf pulp. F127 (20% w/w) gel and the aloe vera/F127 blend gel were obtained by using the cold method. Fourier transform infrared spectroscopy and X‐ray diffraction analyses of lyophilized samples did not show any important copolymer interaction between aloe vera gel and F127. However, in aqueous medium, the dynamic light scattering data showed that there was an important reduction in micelle size with increasing temperature of the aloe vera/F127 blend hydrogel. The differential scanning calorimetry results indicate that the aloe vera/F127 blend has a higher micellization temperature, affected by the lower dehydrating effect of the poly(propylene oxide) blocks during the micelle formation in comparison to F127 gel. The texture analyses (hardness and adhesiveness) showed that the addition of aloe vera gel did not change the Pluronic F127 gel texture properties. The photosensitizer zinc phthalocyanine (ZnPC) was incorporated into the aloe vera/F127 blend, and the results suggest that this formulation is suitable as a ZnPC delivery system for photodynamic therapy. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46191.
Investigation of the mechanical, thermal, and anticorrosion properties of epoxy nanocomposite coatings: Effect of synthetic hardener and nanoporous graphene
Authors: Naderi Mehdi , Hoseinabadi Morteza , Najafi Mohammad , Motahari Siamak , Shokri Mohammad
Published: January 2018

In the present study, epoxy samples containing nanoporous graphene (NPG) were synthesized and analyzed in terms of mechanical, morphological, thermal, adhesion, and anticorrosion properties. To this end, the employed curing agents (hardeners) were synthesized and NPG content was varied from 0 to 1 wt %. By using a hardener with aliphatic side chains, the toughness of the nanocomposite was improved without a decrease in the modulus. Adding 1 wt % NPG increased the modulus of the nanocomposite by about 30%. The dynamic mechanical results showed an increment in the glass transition of the samples containing 1 wt % NPG. Field emission scanning electron microscopy images were used to observe the fracture surface of the nanocomposites. The thermogravimetric analysis analysis also confirmed that using synthetic hardener and NPG as the nanofiller enhanced the thermal resistance of the samples. The images of the protected metal panel surfaces and their coatings were used to study adhesion and anticorrosion properties. These results indicated that the hardener synthesized in this work along with NPG improved the mechanical, thermal, adhesion, and anticorrosion properties of the epoxy nanocomposites effectively. The specific characteristic of the synthetic hardener was its chemical structure including both aliphatic and cyclic polyamines as the side groups. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46201.