bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of nicotinamide adenine dinucleotide phosphate oxidase in chronic rhinosinusitis with nasal polyps
Authors: Zheng Kaili , Hao Jin , Xiao Lei , Wang Min , Zhao Yan , Fan Dachuan , Li Ying , Wang Xiangdong , Zhang Luo 
Published: February 2020

BackgroundNicotinamide adenine dinucleotide phosphate (NADPH) oxidase produces reactive oxygen species (ROS) involved in oxidative stress and signal transduction. Recent studies have suggested that NADPH oxidase is associated with the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). The aim of this study was to detect the expression of NADPH oxidase subunits and 4‐hydroxynonenal (4‐HNE) in nasal polyp tissue and normal nasal mucosa, in order to explore the possible role played by NADPH oxidase in the pathogenesis of CRSwNP.MethodsThirteen patients with CRSwNP and 9 normal control subjects were selected to participate in this study, in which we evaluated the expression of different NADPH oxidase subunits (gp91phox, p67phox, p47phox, and p22phox) in nasal polyp (NP) tissue and control mucosa by Western blotting and real‐time polymerase chain reaction (PCR). Immunohistochemistry and immunofluorescence staining were used to detect expression of the p67phox subunit and 4‐HNE in NP tissue and normal nasal mucosa.ResultsWestern blot and real‐time PCR results showed that p67phox expression was significantly increased in NP tissue when compared with its expression in control mucosa (p = 0.004). p67phox was expressed in the eosinophils and neutrophils found in NP tissue, but not in the macrophages. Additionally, the levels of 4‐HNE expression were also significantly increased in NP tissue when compared with control mucosa (p = 0.001).ConclusionThe levels of p67phox messenger RNA (mRNA) and protein as well as 4‐HNE were both upregulated in NP tissue, suggesting that p67phox and oxidative stress play roles in the pathogenesis of CRSwNP.
Control of Stereoselectivity in Diverse Hapalindole Metabolites is Mediated by Cofactor‐Induced Combinatorial Pairing of Stig Cyclases
Authors: Li Shasha , Newmister Sean A. , Lowell Andrew N. , Zi Jiachen , Chappell Callie R. , Yu Fengan , Hohlman Robert M. , Orjala Jimmy , Williams Robert M. , Sherman David H. 
Published: February 2020

AbstractStereospecific polycyclic core formation of hapalindoles and fischerindoles is controlled by Stig cyclases through a three‐step cascade involving Cope rearrangement, 6‐exo‐trig cyclization, and a final electrophilic aromatic substitution. Reported here is a comprehensive study of all currently annotated Stig cyclases, revealing that these proteins can assemble into heteromeric complexes, induced by Ca2+, to cooperatively control the stereochemistry of hapalindole natural products.
Molekulare Photochemie: Moderne Entwicklungen in der theoretischen Chemie
Authors: Mai Sebastian , González Leticia 
Published: February 2020

AbstractPhotochemie ist ein faszinierendes Teilgebiet der Chemie, das sich mit der Wechselwirkung von Molekülen und Licht befasst. Die Simulation von lichtinduzierten Prozessen spielt auch in anderen Forschungsgebieten wie Biologie, Materialwissenschaften oder Medizin eine bedeutende Rolle. Dieser Kurzaufsatz beleuchtet die jüngsten Entwicklungen in der theoretischen Chemie, die das Ziel haben, experimentelle Genauigkeit bei der Berechnung von elektronisch angeregten Zuständen von Molekülen und bei der Simulation von deren lichtinduzierten Dynamiken zu erreichen. Wir konzentrieren uns dabei auf neue, aufstrebende Methoden und zeigen ausgewählte Beispiele, welche die Fortschritte der letzten Jahre für folgende Themen aufzeigen: die Voraussage komplexer Elektronenstrukturen mit starker Korrelation, die Berechnung von großen Molekülen, die Beschreibung von multi‐chromophorischen Systemen und die Simulation nicht‐adiabatischer Moleküldynamik auf langen Zeitskalen; dies umfasst Moleküle sowohl in der Gasphase als auch in komplexer biologischer Umgebung.
Total Synthesis of Farnesin through an Excited‐State Nazarov Reaction
Authors: Que Yonglei , Shao Hao , He Haibing , Gao Shuanhu 
Published: February 2020

AbstractThe asymmetric total synthesis of farnesin, a rearranged ent‐kaurenoid, was achieved through a convergent approach involving photo‐Nazarov and intramolecular aldol cyclizations to build the syn‐syn‐syn hydrofluorenol ABC ring system and bicyclo[3.2.1]octane CD ring system in the first application of a UV‐light‐induced excited‐state Nazarov cyclization of a non‐aromatic dicyclic divinyl ketone in a total synthesis. Unlike the conventional acid‐promoted ground‐state Nazarov reaction, the excited‐state Nazarov reaction enables stereospecific formation of the highly strained syn‐syn‐syn‐fused hydrofluorenone scaffold through a disrotatory cyclization.
Highly efficient fire retardant behavior, thermal stability, and physicomechanical properties of rigid polyurethane foam based on recycled poly(ethylene terephthalate)
Authors: Pham Chi T. , Nguyen Binh T. , Phan Huong T. Q. , Pham Lam H. , Hoang Cuong N. , Nguyen Nguyen N. , Lee Pyoung‐Chan , Kang Soo‐Jung , Kim Jinhwan , Hoang DongQuy 
Published: February 2020

AbstractThis study focused on the burning phenomena, thermal stability, and physicomechanical properties of polyurethane foam based on recycled poly(ethylene terephthalate) (RPUF) with and without halogen‐free flame retardants (FRs). Flammability behavior and associated mechanisms were studied by cone calorimetry, LOI, UL 94, FTIR, TGA, FE‐SEM, and XPS. The results of cone calorimeter testing indicate improved FR performance with notable reductions in peak heat release rate (~39.1%), peak CO production (~61.7%), and peak CO2production (~43.0%). LOI values significantly increase, up to 29.5–47.1%, in the presence of FRs, and V‐0 ratings are attained even at a rather low loading of FR (6.07 wt%). Meanwhile, the RPUF completely burns to the holder clamp with a low LOI value (17%), and it do not pass the UL94 HB standard. The addition of FRs notably improves the residual char of RPUF, indicating that FRs contributed to the formation of a barrier layer to protect RPUF during degradation. The comparison between experimentally determined TGA results and calculated values provides support for the effect of FRs on the thermal degradation behavior of RPUF. Sorption isotherm experiments of RPUF/FR systems show low moisture absorptivity and a weak hysteresis effect due to strong intermolecular bonds between RPUF and added FRs. The compression test, density, and morphology of foam samples are also discussed.
Antibacterial porous xanthan‐based films containing flavoring agents evaluated by near infrared chemical imaging technique
Authors: Raschip Irina E. , Paduraru‐Mocanu Oana M. , Nita Loredana E. , Dinu Maria V. 
Published: February 2020

AbstractXanthan gum (XG) is a widely applied natural polysaccharide in food industry as thickening agent. Nowadays, one of the major problems is that some food products are found to be contaminated by pathogenic bacteria such as Escherichia coli and Staphylococcus aureus reducing so, their shelf life. This research aims to demonstrate the antibacterial activity of some biodegradable formulation XG‐lignin hydrogel films and their potential application as carriers for controlled release of flavoring compounds. The XG‐lignin films containing an aspen wood lignin type showed a high antibacterial activity against Salmonella Typhymurium ATCC 14028, E. coli ATCC 25922 and Listeria monocytogenes ATCC 25922 bacteria compared with those containing softwood lignin, or lignin from annual plants. Surface morphology indicated a homogeneous distribution of both components within the hydrogel network and the generation of a porous structure after swelling and lyophilization. Additionally, near infrared chemical imaging technique was used as nondestructive method to observe the spatial distribution of the polymeric components and vanillin into the hydrogel films as well as its release profile. The vanillin release rate dependence on the lignin type was also evidenced, a retarded release of vanillin being observed. These results give an important insight into the use of XG, lignin, and vanillin for the development of new edible films for active packaging materials.
Photocatalytic degradation and heat reflectance recovery of waterborne acrylic polymer/ZnO nanocomposite coating
Authors: Nguyen Thien Vuong , Dao Phi Hung , Nguyen Tuan Anh , Dang Viet Hung , Ha Minh Nguyet , Nguyen Thi Thuy Trang , Vu Quoc Trung , Nguyen Ngọc Linh , Dang Tran Chien , Nguyen‐Tri Phuong , Tran Dai Lam , Lu Le Trong 
Published: February 2020

AbstractThis work aims to clarify the photocatalytic degradation mechanism and heat reflectance recovery performance of waterborne acrylic polymer/ZnO nanocomposite coating. To fabricate the nanocomposite coating, ZnO nanoparticles (nano‐ZnO) were dispersed into acrylic polymer matrix at the various concentrations from 1 to 6% (by total weight of resin solids). The photocatalytic degradation of nanocomposite coating under ultraviolet (UV) light irradiation has been investigated by monitoring its weight loss and chemical/microstructural/morphological changes. As the topcoat layer, its heat reflectance recovery has been evaluated under UV/condensation exposure by using an artificial dirty mixture of 85 wt% nanoclay, 10 wt% silica particles (1–5 μm), 1 wt% carbon black, and 2 wt% engine oil. After 108‐cycle UV/condensation exposure, infrared spectra and weight loss analysis indicated that the maximal degradation for nanocomposite coating is observed at 1 wt% nano‐ZnO. On the other hand, after 96 hr of UV light exposure, the nanocomposite coating with1 wt% nano‐ZnO could restore effectively the reflective index of solar‐heat reflectance coating (from 58.45 to 80.78%). Finally, the photodegradation mechanism of this waterborne acrylic polymer coating has been proposed as the UV‐induced formation of CCCO conjugated double bonds. As a result, its self‐cleaning phenomenon can be achieved as the recovery of heat reflectance.
Synthesis of Pd‐Pt Ultrathin Assembled Nanosheets as Highly Efficient Electrocatalysts for Ethanol Oxidation
Authors: Han Yeji , Kim Jeonghyeon , Lee Su‐Un , Choi Sang‐Il , Hong Jong Wook 
Published: February 2020

AbstractControl over composition and morphology of nanocrystals (NCs) is significant to develop advanced catalysts applicable to polymer electrolyte membrane fuel cells and further overcome the performance limitations. Here, we present a facile synthesis of Pd−Pt alloy ultrathin assembled nanosheets (UANs) by regulating the growth behavior of Pd−Pt nanostructures. Iodide ions supplied from KI play as capping agents for the {111} plane to promote 2‐dimensional (2D) growth of Pd and Pt, and the optimal concentrations of cetyltrimethylammonium chloride and ascorbic acid result in the generation of Pd−Pt alloy UANs in high yield. The prepared Pd−Pt alloy UANs exhibited the remarkable enhancement of the catalytic activity and stability toward ethanol oxidation reaction compared to irregular‐shaped Pd−Pt alloy NCs, commercial Pd/C, and commercial Pt/C. Our results confirm that the Pd−Pt alloy composition and ultrathin 2D morphology offer high accessible active sites and favorable electronic structure for enhancing electrocatalytic activity.
Rivals without a cause? Relative performance feedback creates destructive competition despite aligned incentives
Authors: Woike Jan K. , Hafenbrädl Sebastian 
Published: February 2020

AbstractWhether people compete or cooperate with each other has consequences for their own performance and that of organizations. To explain why people compete or cooperate, previous research has focused on two main factors: situational outcome structures and personality types. Here, we propose that—above and beyond these two factors—situational cues, such as the format in which people receive feedback, strongly affect whether they act competitively, cooperatively, or individualistically. Results of a laboratory experiment support our theorizing: After receiving ranking feedback, both students and experienced managers treated group situations with cooperative outcome structures as competitive and were in consequence willing to forgo guaranteed financial gains to pursue a—financially irrelevant—better rank. Conversely, in dilemma situations, feedback based on the joint group outcome led to more cooperation than ranking feedback. Our study contributes to research on competition, cooperation, interdependence theory, forced ranking, and the design of information environments.
What Doesn't Kill You Makes You Stronger: Transposons as Dual Players in Chromatin Regulation and Genomic Variation
Authors: Percharde Michelle , Sultana Tania , Ramalho‐Santos Miguel 
Published: February 2020

AbstractTransposable elements (TEs) are sequences currently or historically mobile, and are present across all eukaryotic genomes. A growing interest in understanding the regulation and function of TEs has revealed seemingly dichotomous roles for these elements in evolution, development, and disease. On the one hand, many gene regulatory networks owe their organization to the spread of cis‐elements and DNA binding sites through TE mobilization during evolution. On the other hand, the uncontrolled activity of transposons can generate mutations and contribute to disease, including cancer, while their increased expression may also trigger immune pathways that result in inflammation or senescence. Interestingly, TEs have recently been found to have novel essential functions during mammalian development. Here, the function and regulation of TEs are discussed, with a focus on LINE1 in mammals. It is proposed that LINE1 is a beneficial endogenous dual regulator of gene expression and genomic diversity during mammalian development, and that both of these functions may be detrimental if deregulated in disease contexts.
SPME‐GC/MS Analysis of Volatile Compounds Contained in the Insect Larvae of Tenebrio molitor and Leptinotarsa decemlineata before and after Using Insecticides
Authors: Wojciechowska Marta , Gołębiowski Marek 
Published: February 2020

AbstractThe larvae of two harmful insect species Tenebrio molitor and Leptinotarsa decemlineata were analyzed. The insects were sprayed with insecticides containing the active substances cyfluthrin and deltamethrin (T. molitor), and thiamethoxam and acetamiprid (L. decemlineata). The sprayed insect larvae were left for 24, 48 and 72 h. Samples were then prepared using SPME fiber to identify the volatile compounds contained in the larvae. The determinations were made by gas chromatography coupled with mass spectrometry (GC/MS). Chemical compounds were found in the analyzed samples: alkanes, aldehydes, ketones, esters, terpenes, fatty acids. In the samples prepared from T. molitor larvae, more than 20 % of aldehydes and 8–41 % of alkanes were determined. In the samples from L. decemlineata, fatty acids were 8–65 % depending on the length of time after applying the insecticide.
Ruthenium‐Catalyzed Double C(sp2)−H Functionalizations of Fumaramides with Alkynes for the Divergent Synthesis of Pyridones and Naphthyridinediones
Authors: Han Zhi‐Jian , Zhang Ze‐Xuan , Li Wei‐Ping , Du Zhi‐Hong , Tao Bao‐Xiu , Da Chao‐Shan , Jiao Zuo‐Yi , Chen Hao , Li Yumin 
Published: February 2020

AbstractTransition‐metal‐catalyzed C−H functionalization of aromatic secondary amides with alkynes mainly undergo C−H/N−H annulation but rarely undergo ortho‐alkenylation. It is particularly challenging to selectively realize both oxidative annulation and ortho‐alkenylation of aromatic secondary amides with alkynes in the transition‐metal‐catalysis. In this article, we synthesized fully‐substituted 2‐pyridones and 2,6‐naphthyridine‐1,5‐diones via C(sp2)−H functionalization of fumaramides for the first time. Under the Ru‐catalysis, fumaramides and 1,2‐diaryl ethynes first undergo C−H/N−H annulation leading to the intermediate 2‐pyridone with an exocyclic secondary amide, and subsequently undergo the unexpected stereoselective C−H alkenylation to realize fully substituted 2‐pyridones bearing an exocyclic anti alkenyl group. On the addition of K2CO3, however, the transformation of fumaramides with 1,2‐dialkyl ethyne undergoes two conventional C−H/N−H annulations to provide 2,6‐naphthyridine‐1,5‐diones in high yield. The two procedures can be successfully enlarged to gram‐scales without erosion of the yields. In addition, some 2‐pyridones and 2,6‐naphthyridine‐1,5‐diones emitting clear ultraviolent and fluorescent light, indicating the potential utility of this work in organic light‐emitting materials.
Fabrication of Copper‐based Silica‐coated Magnetic Nanocatalyst for Efficient One‐pot Synthesis of Chalcones via A3 Coupling of Aldehydes‐Alkynes‐Amines
Authors: Yadav Priya , Yadav Manavi , Gaur Rashmi , Gupta Radhika , Arora Gunjan , Rana Pooja , Srivastava Anju , Sharma Rakesh K. 
Published: February 2020

AbstractIn the present work, we have synthesized bioactive and pharmacologically important chalcone motifs by employing green and efficient silica‐coated magnetically separable catalyst, Cu@DBM@ASMNPs. The highly proficient nanocatalyst proves its invincibility for the solvent‐free one‐pot synthesis of chalcone moieties by A3 coupling of aldehydes‐alkynes‐amines in good to excellent yields. The fabricated Cu@DBM@ASMNPs was structurally and chemically analyzed by various techniques such as FT‐IR, SEM, TEM, VSM, ICP‐MS, ED‐XRF and XPS. The programmed catalytic protocol has been proceeded via isomerization‐hydrolysis reaction of aldehydes and terminal alkynes. The present strategy offered much greener and efficacious synthesis of chalcones by adding benefits such as solvent‐less synthetic protocol and much shorter reaction time. Other interesting and noteworthy features of this methodology are broad substrate scope, mild reaction conditions, and reusability up to seven runs without significant loss of its catalytic activity which renders it an environmentally friendly and remarkable protocol from industrial point of view.
A High‐Performance Membraneless Microfluidic Microbial Fuel Cell for Stable, Long‐Term Benchtop Operation Under Strong Flow
Authors: Amirdehi Mehran Abbaszadeh , Khodaparastasgarabad Nastaran , Landari Hamza , Zarabadi Mir Pouyan , Miled Amine , Greener Jesse 
Published: February 2020

AbstractStrong control over experimental conditions in microfluidic channels provides a unique opportunity to study and optimize membraneless microbial fuel cells (MFCs), particularly with respect to the role of flow. However, improved performance and transferability of results to the wider MFC community require improvements to device stability under all applied operational conditions. To address these challenges, we present an easy‐to‐fabricate membraneless MFC that combines i) O2 protection via a gas diffusion barrier, ii) integrated graphite electrodes, and iii) optimized electrode placement to avoid cross‐contamination under all applied flow rates. Attention to all of these design features in the same platform resulted in the operation of a MFC with a pure‐culture anaerobic Geobacter sulfurreducens biofilm for half a year, that is, six times longer than previously reported, without the use of an oxygen scavenger. As a result of higher device stability under high flow rates, power densities were four times higher than reported previously for microfluidic MFCs with the same biofilm.
Compressing a Non‐Planar Aromatic Heterocyclic [7]Helicene to a Planar Hetero[8]Circulene
Authors: Lousen Bodil , Pedersen Stephan K. , Bols Pernille , Hansen Kasper H. , Pedersen Michelle R. , Hammerich Ole , Bondarchuk Sergey , Minaev Boris , Baryshnikov Glib V. , Ågren Hans , Pittelkow Michael 
Published: February 2020

AbstractThis work describes a synthetic approach where a non‐planar aromatic heterocyclic [7]helicene is compressed to yield a hetero[8]circulene containing an inner antiaromatic cyclooctatetraene (COT) core. This [8]circulene consists of four benzene rings and four heterocyclic rings, and it is the first heterocyclic [8]circulene containing three different heteroatoms. The synthetic pathway proceeds via a the flattened dehydro‐hetero[7]helicene, which is partially a helicene and partially a circulene: it is non‐planar and helically chiral as helicenes, and contains a COT motif like [8]circulenes. The antiaromaticity of the COT core is confirmed by nucleus independent chemical shift (NICS) calculations. The planarization from a helically π‐conjugated [7]helicene to a fully planar heterocyclic [8]circulene significantly alters the spectroscopic properties of the molecules. Post‐functionalization of the [7]helicenes and the [8]circulenes by oxygenation of the thiophene rings to the corresponding thiophene‐sulfones allows an almost complete fluorescence emission coverage of the visible region of the optical spectrum (400–700 nm).
Fundamental Insights into the Covalent Silane Functionalization of NiFe Layered Double Hydroxides
Authors: Carrasco Jose A. , Seijas‐Da Silva Alvaro , Oestreicher Víctor , Romero Jorge , Márkus Bence G. , Simon Ferenc , Vieira Bruno J. C. , Waerenborgh João C. , Abellán Gonzalo , Coronado Eugenio 
Published: February 2020

AbstractLayered double hydroxides (LDHs) are a class of 2D anionic materials exhibiting wide chemical versatility and promising applications in different fields, ranging from catalysis to energy storage and conversion. However, the covalent chemistry of this kind of 2D materials is still barely explored. Herein, the covalent functionalization with silanes of a magnetic NiFe‐LDH is reported. The synthetic route consists of a topochemical approach followed by anion exchange reaction with surfactant molecules prior to covalent functionalization with the (3‐aminopropyl)triethoxysilane (APTES) molecules. The functionalized NiFe‐APTES was fully characterized by X‐ray diffraction, infrared spectroscopy, electron microscopy, thermogravimetric analysis coupled with mass spectrometry and 29Si solid‐state nuclear magnetic resonance, among others. The effect on the electronic properties of the functionalized LDH was investigated by a magnetic study in combination with Mössbauer spectroscopy. Moreover, the reversibility of the silane‐functionalization at basic pH was demonstrated, and the quality of the resulting LDH was proven by studying the electrochemical performance in the oxygen evolution reaction in basic media. Furthermore, the anion exchange capability for the NiFe‐APTES was tested employing CrVI, resulting in an increase of 200 % of the anion retention. This report allows for a new degree of tunability of LDHs, opening the door to the synthesis of new hybrid architectures and materials.