bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anti‐CRISPRs: The natural inhibitors for CRISPR‐Cas systems
Authors: Zhang Fei , Song Guoxu , Tian Yong 
Published: May 2019

AbstractCRISPR (clustered regularly interspaced short palindromic repeats)‐Cas (CRISPR associated protein) systems serve as the adaptive immune system by which prokaryotes defend themselves against phages. It has also been developed into a series of powerful gene‐editing tools. As the natural inhibitors of CRISPR‐Cas systems, anti‐CRISPRs (Acrs) can be used as the “off‐switch” for CRISPR‐Cas systems to limit the off‐target effects caused by Cas9. Since the discovery of CRISPR‐Cas systems, much research has focused on the identification, mechanisms and applications of Acrs. In light of the rapid development and scientific significance of this field, this review summarizes the history and research status of Acrs, and considers future applications.
Linear‐Dendritic Alternating Copolymers
Authors: Sun Haotian , Haque Farihah M. , Zhang Yi , Commisso Alex , Mohamed Mohamed Alaa , Tsianou Marina , Cui Honggang , Grayson Scott M. , Cheng Chong 
Published: May 2019

AbstractHerein, the design, synthesis, and characterization of an unprecedented copolymer consisting of alternating linear and dendritic segments is described. First, a 4th‐generation Hawker‐type dendron with two azide groups was synthesized, followed by a step‐growth azide‐alkyne “click” reaction between the 4th‐generation diazido dendron and poly(ethylene glycol) diacetylene to create the target polymers. Unequal reactivity of the functional groups was observed in the step‐growth polymerization. The resulting copolymers, with alternating hydrophilic linear and hydrophobic dendritic segments, can spontaneously associate into a unique type of microphase‐segregated nanorods in water.
Modifying the Thioester Linkage Affects the Structure of the Acyl Carrier Protein
Authors: Sztain Terra , Patel Ashay , Lee D. John , Davis Tony D. , McCammon J. Andrew , Burkart Michael D. 
Published: May 2019

AbstractAt the center of many complex biosynthetic pathways, the acyl carrier protein (ACP) shuttles substrates to appropriate enzymatic partners to produce fatty acids and polyketides. Carrier proteins covalently tether their cargo via a thioester linkage to a phosphopantetheine cofactor. Due to the labile nature of this linkage, chemoenzymatic methods have been developed that involve replacement of the thioester with a more stable amide or ester bond. We explored the importance of the thioester bond to the structure of the carrier protein by using solution NMR spectroscopy and molecular dynamics simulations. Remarkably, the replacement of sulfur with other heteroatoms results in significant structural changes, thus suggesting more rigorous selections of isosteric substitutes is needed.
Enantioselective Palladium‐Catalyzed Cross‐Coupling of α‐Bromo Carboxamides and Aryl Boronic Acids
Authors: Li Bowen , Li Tiejun , Aliyu Muinat A. , Li Zhen Hua , Tang Wenjun 
Published: May 2019

AbstractWe herein report an enantioselective palladium‐catalyzed cross‐coupling between α‐bromo carboxamides and aryl boronic acids, generating a series of chiral α‐aryl carboxamides in good yields and excellent enantioselectivities. The development of a chiral P,P=O ligand was critical in overcoming the second transmetalation issue and allows the first asymmetric palladium‐catalyzed coupling of α‐bromo carbonyl compounds.
Iron (III)‐porphyrin Complex FeTSPP as an efficient catalyst for synthesis of tetrazole derivatives via [2 + 3]cycloaddition reaction in aqueous medium
Authors: El‐Remaily Mahmoud Abd El Aleem Ali Ali , Elhady O.M. 
Published: May 2019

The metal complex (5,10,15,20‐tetrakis‐(4‐sulfonatophenyl)‐porphyrin‐iron (III) chloride (FeTSPP) was new employed in an environmentally benign protocol as an efficient catalyst for a “click” chemistry approach for the synthesis of tetrazole and guanindinyltetrazole derivatives via [2 + 3] cycloaddition reaction of nitriles and azide derivatives in aqueous medium. The synthesized compounds were obtained in excellent yield, short reaction times and a recoverable catalyst.
Palladium nanoparticles embedded chitosan/poly(vinyl alcohol) composite nanofibers as an efficient and stable heterogeneous catalyst for Heck reaction
Authors: Ye Zeyu , Zhang Benben , Shao Linjun , Xing Guiying , Qi Chenze , Tao Hongyu 
Published: May 2019

ABSTRACTIn this study, palladium nanoparticles were successfully embedded into modified chitosan/poly(vinyl alcohol) composite nanofibers (Pd‐CS/PVA nanofibers) by electrospinning. Then, the Pd‐CS/PVA nanofibers were treated at evaluated temperature to improve its solvent resistance andin situreduce Pd2+cations into Pd0active species. The incorporated palladium nanoparticles with ultra small mean diameter of 3.73 ± 1.04 nm are evenly distributed inside the Pd‐CS/PVA nanofiber. The resulting Pd‐CS/PVA nanofiber mat exhibits high catalytic activity for Heck reaction of aromatic iodides with alkenes and can be recycled for 18 times without loss of initial activity. The high catalytic activity and stability of Pd‐CS/PVA nanofiber mat can be attributed to the ultra small diameter nanofibers, strong chelating ability of chitosan, and fine embedment of palladium species inside the nanofiber. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 48026.
Synergistic modification of carbon fiber by electrochemical oxidation and sizing treatment and its effect on the mechanical properties of carbon fiber reinforced composites
Authors: Wu Bo , Zheng Guo , Wang Rui , Zhou Cun , Hu Yunjie , Lv Jingcheng 
Published: May 2019

ABSTRACTIn this article, The CF surface was modified by the synergistic modification of electrochemical oxidation and sizing treatment. Firstly, the electrochemical oxidation was carried out using fatty alcohol polyoxyethylene ether phosphate (AEOPK) as the electrolyte. The content of active groups on the modified CF surface increased by 235%. However, the strength of CF monofilament decreased due to the etching. Then, the electrochemically oxidized CFs were sized with the phosphate modified epoxy resin (PAEK). The etched defects on CF surface caused by the electrochemical oxidation were repaired by sizing agent molecules according to the AFM results. Furthermore, the spreadability of PAEK emulsion on the CF surface, the content of CF surface groups and the interaction of CFRC were characterized by using the monofilament contact angle, XPS and Raman spectroscopy. The results suggested that the synergistic modification could improve the CF surface activity, facilitate the spreading of PAEK on the CF surface, and increase the interaction between the CFs and the resin matrix. There were 20.3 and 22.6% enhancement in the breaking strength and elongation of CF monofilament. In addition, the interlaminar shear strength (ILSS) of CFRC prepared with synergistically modified CFs was increased from 12.81 to 33.04 MPa. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48028.
Biosorption of cadmium by potential probiotic Pediococcus pentosaceus using in vitro digestion model
Authors: Le Bao , Yang Seung Hwan 
Published: May 2019

AbstractAn exponential increase of heavy metal toxicant in the human body is a growing health‐related problem. In the present study, Pediococcus pentosaceus FB145 and FB181 strains were isolated from fermented seafood and served as highly Cd‐resistant strains. The unchanged structural cells of P. pentosaceus strains after treatment with Cd cations were investigated using a scanning electron microscope energy dispersive X‐ray analysis. Furthermore, both P. pentosaceus strains showed strong human gastrointestinal tract resistance properties. The Cd biosorption results fit the pseudo–second‐order kinetics with capacities for P. pentosaceus FB145 and FB181 for Cd were 52.8 and 50.3 mg/g, respectively, whereas the maximum biosorption capacities were 52.65 and 50.35 mg/g, respectively. The equilibrium data were well fitted to the Freundlich isotherm model. The binding of Cd to bacterial cells may be caused by the presence of different functional groups such as carboxyl, amide, and phosphate on cell surface, which was confirmed by the Fourier transform infrared‐attenuated total reflectance spectra. Moreover, these strains decreased the Cd bioaccessibility by 44.7–46.8% in the in vitro digestion model. These findings indicate that P. pentosaceus FB145 and FB181 are novel potent biosorbent for preventing cadmium toxicity and reducing its absorption into the human body.
Untersuchung des Zug‐ und Verbundverhaltens von Basaltfaserverstärkter Kunststoff‐Stabbewehrung in Beton
Authors: Wolf Benjamin , Glomb Daniel Sebastian , Kustermann Andrea , Dauberschmidt Christoph 
Published: May 2019

AbstractBei der Instandsetzung von Stahlbetonbauteilen muss, um die Dauerhaftigkeit sicherzustellen, die Betondeckung hinreichend groß gewählt werden. Der Einsatz alternativer Bewehrungsmaterialien wie z. B. Basalt als Faserverbundstab bietet durch die Korrosionsbeständigkeit gegenüber Karbonatisierung und Chlorideinwirkung die Möglichkeit, die Betondeckung zur Sicherstellung der Dauerhaftigkeit zu minimieren und gleichzeitig korrosionsresistente Bauteile zu erstellen. Nachfolgend werden – als Auszug aus einem Forschungsprojekt zur Untersuchung zur Instandsetzung von Sichtbetonfassadenelementen mittels Basaltstabbewehrung und Spritzbeton – Untersuchungen zum Tragverhalten von basaltbewehrten Verbundkörpern präsentiert. Die geprüften „Basaltfaserverstärkten Kunststoff‐Bewehrungsstäbe“ (BFVK‐Stab) weisen am reinen Stab höhere Zugfestigkeiten bei geringeren E‐Moduln als vergleichbare Betonstähle auf. Im zentrischen Zugversuch an bewehrten Betonknochenproben zeigen sich bei den Prüfkörpern mit der BFVK‐Stabbewehrung Längsrisse infolge hoher Spannungen im Verbundbereich sowie eine höhere Anzahl an breiteren Querrissen als im betonstahlbewehrten Referenzprüfkörper. Mithilfe numerischer Simulationen kann das Zug‐Verformungsverhalten der Prüfkörper gut nachgebildet werden. Bei der lichtmikroskopischen Untersuchung präparierter Prüfkörper nach der Zugprüfung zeigten sich verstärkt Mikrorisse, ausgehend von der Kontaktzone zwischen BFVK‐Stab zur Betonmatrix. Bei den Auszugsversuchen versagte stets der Beton, nicht die BFVK‐Stabbewehrung.Die Untersuchungsergebnisse belegen, dass der Einsatz von Basaltstabbewehrung in Beton die Herstellung dauerhafter Bauteile mit geringen Betondeckungen ermöglicht. Weitere Versuche wurden bereits zum Biegetragverhalten, zur Dauerschwingfestigkeit und Dauerhaftigkeit durchgeführt. Derzeit werden weitere Basaltbewehrungsstäbe anderer Geometrien untersucht.
Comparison of microbial and transient expression (tobacco plants and plant‐cell packs) for the production and purification of the anticancer mistletoe lectin viscumin
Authors: Gengenbach Benjamin B. , Keil Linda L. , Opdensteinen Patrick , Müschen Catherine R. , Melmer Georg , Lentzen Hans , Bührmann Jens , Buyel Johannes F. 
Published: May 2019

AbstractCancer is the leading cause of death in industrialized countries. Cancer therapy often involves monoclonal antibodies or small‐molecule drugs, but carbohydrate‐binding lectins such as mistletoe (Viscum album) viscumin offer a potential alternative treatment strategy. Viscumin is toxic in mammalian cells, ruling them out as an efficient production system, and it forms inclusion bodies in Escherichia coli such that purification requires complex and lengthy refolding steps. We therefore investigated the transient expression of viscumin in intact Nicotiana benthamiana plants and Nicotiana tabacum Bright Yellow 2 plant‐cell packs (PCPs), comparing a full‐length viscumin gene construct to separate constructs for the A and B chains. As determined by capillary electrophoresis the maximum yield of purified heterodimeric viscumin in N. benthamiana was ~7 mg/kg fresh biomass with the full‐length construct. The yield was about 50% higher in PCPs but reduced 10‐fold when coexpressing A and B chains as individual polypeptides. Using a single‐step lactosyl‐Sepharose affinity resin, we purified viscumin to ~54%. The absence of refolding steps resulted in estimated cost savings of more than 80% when transient expression in tobacco was compared with E. coli. Furthermore, the plant‐derived product was ~3‐fold more toxic than the bacterially produced counterpart. We conclude that plants offer a suitable alternative for the production of complex biopharmaceutical proteins that are toxic to mammalian cells and that form inclusion bodies in bacteria.
Investigating cultural aspects in the fundamental diagram using convolutional neural networks and virtual agent simulation
Authors: Migon Favaretto Rodolfo , Rosa dos Santos Roberto , Raupp Musse Soraia , Vilanova Felipe , Brandelli Costa Angelo 
Published: May 2019

AbstractThis paper presents a study, organized in two phases, regarding group behavior in a controlled experiment focused on differences in an important attribute that vary across cultures—personal spaces. First, we want to study and compare the spatial behavior different populations adopt with respect to their personal space. Second, we want to use simulation of virtual agents to artificially generate movements of people in similar situations and validate them using real video sequences. Our main goal is to be able to extract from video sequences and then simulate variations in populations in a coherent way with literature that studies cultural aspects. In addition to the cultural aspects, we also investigate the personality model in the studied videos using OCEAN (Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism). Finally, we propose a way to simulate the fundamental diagram experiment from other countries using the OCEAN psychological trait model as input. Results indicate that the simulated countries have consistent characteristics with the expected literature.
Procedural‐related coronary atrial branch occlusion during primary percutaneous coronary intervention for ST‐segment elevation myocardial infarction and atrial arrhythmias at follow‐up
Authors: Montero Cabezas José M. , Abou Rachid , Goedemans Laurien , Agüero Jaume , Schalij Martin J. , Ajmone Marsan Nina , Fuster Valentín , Ibáñez Borja , Bax Jeroen J. , Delgado Victoria 
Published: May 2019

AbstractObjectivesTo evaluate the frequency of procedural‐related atrial branch occlusion in ST‐segment elevation myocardial infarction (STEMI) patients and its association with atrial arrhythmias at 1‐year follow‐up.BackgroundAtrial ischemia due to procedural‐related coronary atrial branch occlusion in elective percutaneous coronary intervention (PCI) has been associated with atrial arrhythmias. Its role in a STEMI scenario is unknown.MethodsSTEMI patients treated with primary PCI were classified according to the loss or patency of an atrial branch at the end of the procedure. The occurrence of atrial arrhythmias was documented on 24‐hr Holter‐ECG at 3 and 6 months or on ECG during 1‐year follow‐up visits.ResultsOf 900 patients, 355 (age 61 ± 12 years, 79% male) underwent primary PCI involving the origin of an atrial branch. Procedural‐related coronary atrial branch occlusion was observed in 18 (5%) individuals). During 1‐year follow‐up, 33% of patients with procedural‐related atrial branch occlusion presented atrial arrhythmias, as compared with 55% in those with a patent atrial branch (p = .088). Age, no previous history of myocardial infarction, and a reduced flow in the culprit vessel were the only independent correlates of atrial arrhythmias.ConclusionsThe frequency of procedural‐related atrial branch occlusion during primary PCI is low (5%) and is not associated with increased frequency of atrial arrhythmias at 1‐year follow‐up.
Case report and systematic review of iatrogenic left atrial dissection in different cardiovascular specialties: A common treatment for an uncommon complication?
Authors: Cereda Alberto Francesco , De Luca Fabio , Lanzone Alberto M. , Cottini Marzia , Pastori Luca , Sangiorgi Giuseppe 
Published: May 2019

AbstractObjectivesLeft atrial dissection (LatD) is a rare and heterogeneous condition affecting many cardiovascular areas. The present article, by the means of personal case report illustration and systemic review of different clinical management, is aimed to give to clinicians further knowledge on this controversial topic.BackgroundLatD is an exceedingly rare but potentially fatal complication of cardiac surgery or catheter‐based interventional procedures. Most of the cases are iatrogenic and its incidence is expected to grow due to an increase in the number of percutaneous coronary intervention and structural heart disease procedures. The management of this complication is controversial, and it may depend on related etiologies.MethodsWe have reported our single‐case experience and review of the scientific literature, focusing on the decision‐making process and the strategical approach by multimodality imaging techniques.ResultsOur case of LatD with initial hemodynamic instability was surgically treated. Conservative approach is often employed in literature despite the fact that conservative versus surgical approach is debatable, depending on clinical presentation, hemodynamic stability, multimodal imaging findings, and personal experience of the center.ConclusionsAccording to systematic literature review, a watchful‐waiting strategy supported by multimodality imaging could be a safe and effective management in stable LatD.
Ruthenium‐Catalyzed Synthesis of Cyclic and Linear Acetals by the Combined Utilization of CO2, H2, and Biomass Derived Diols
Authors: Beydoun Kassem , Klankermayer Jürgen 
Published: May 2019

AbstractHerein a transition‐metal catalyst system for the selective synthesis of cyclic and linear acetals from the combined utilization of carbon dioxide, molecular hydrogen, and biomass derived diols is presented. Detailed investigations on the substrate scope enabled the selectivity of the reaction to be largely guided and demonstrated the possibility of integrating a broad variety of substrate molecules. This approach allowed a change between the favored formation of cyclic acetals and linear acetals, originating from the bridging of two diols with a carbon‐dioxide based methylene unit. This new synthesis option paves the way to novel fuels, solvents, or polymer building blocks, by the recently established “bio‐hybrid” approach of integrating renewable energy, carbon dioxide, and biomass in a direct catalytic transformation.
Formal Halo‐Meyer–Schuster Rearrangement of Propargylic Acetates through a Novel Intermediate and an Unexampled Mechanistic Pathway
Authors: Sadhukhan Santu , Baire Beeraiah 
Published: May 2019

AbstractA formal, highly stereoselective halo‐Meyer–Schuster rearrangement of inactivated propargylic acetates to (Z)‐α‐haloenones has been reported, under metal free conditions. This cascade process involves a new class of intermediate, i.e., α,α‐dihalo‐β‐acetoxyketones and mechanism to generate the α‐haloenones, employing water as Lewis base. The outcome of the reaction is temperature‐dependent, as room temperature, selectively provides α,α‐dihalo‐β‐acetoxyketones whereas reactions at 100 °C give direct access to α‐haloenones. Either type of product can be obtained in excellent yield. A suitable rationale for the observed highZ‐selectivity for α‐haloenones (based on conformational population) and distinct reaction rates for variousN‐halosuccinimide (NXS) reagents (based on C−X bond strengths) has also been provided.
One‐Step Synthesis of 3,4‐Disubstituted 2‐Oxazolidinones by Base‐Catalyzed CO2 Fixation and Aza‐Michael Addition
Authors: Mannisto Jere K. , Sahari Aleksi , Lagerblom Kalle , Niemi Teemu , Nieger Martin , Sztanó Gábor , Repo Timo 
Published: May 2019

Abstract2‐Oxazolidinones are saturated heterocyclic compounds, which are highly attractive targets in modern drug design. Herein, we describe a new, single‐step approach to 3,4‐disubstituted 2‐oxazolidinones by aza‐Michael addition using CO2 as a carbonyl source and 1,1,3,3‐tetramethylguanidine (TMG) as a catalyst. The modular reaction, which occurs between a γ‐brominated Michael acceptor, CO2 and an arylamine, aliphatic amine or phenylhydrazine, is performed under mild conditions. The regiospecific reaction displays good yields (av. 75 %) and excellent functional‐group compatibility. In addition, late‐stage functionalization of drug and drug‐like molecules is demonstrated. The experimental results suggest a mechanism consisting of several elementary steps: TMG‐assisted carboxylation of aniline; generation of an O‐alkyl carbamate; and the final ring‐forming step through an intramolecular aza‐Michael addition.
The relationship between T‐helper cell polarization and the RANKL/OPG ratio in gingival tissues from chronic periodontitis patients
Authors: Bi Chun‐Sheng , Sun Li‐Juan , Qu Hong‐Lei , Chen Fang , Tian Bei‐Min , Chen Fa‐Ming 
Published: May 2019

AbstractThis study aimed to investigate the relationship between inflammation‐related T‐helper cell polarization and the receptor activator for nuclear factor‐κB ligand (RANKL)/osteoprotegerin (OPG) ratio, which is associated with bone resorption or remodeling of chronic periodontitis patients. Gingival crevicular fluid (GCF) and gingival tissues were obtained from periodontally healthy individuals (PH group) and chronic periodontitis patients (CP group). The GCF levels of IFN‐γ, IL‐4, IL‐17, and IL‐10 linked to T‐helper cell polarization toward the Th1, Th2, Th17, and Treg phenotypes, respectively, were determined by ELISA. The expression levels of these cytokines and the polarized T‐helper cells in gingival tissues were assessed through immunohistochemical and immunofluorescence assays. In addition, the RANKL and OPG expression levels in gingival tissues were detected by immunohistochemical assays, and linear regression analysis was used to identify the potential relationship between T‐helper cell polarization and the RANKL/OPG ratio. In total, 22 individuals and 35 patients were enrolled in the present study. In both GCF and gingival tissues, increased levels of IL‐17 and the decreased levels of IL‐4 and IL‐10 were observed in the CP group. When polarized T‐helper cells were identified in gingival tissues, more Th1 and Th17 cells were found in the CP group, whereas more Th2 and Treg cells were found in the PH group. Although there was no significant difference in OPG expression between the two groups, the RANKL/OPG ratio in the CP group was higher than that in the PH group. The linear regression analysis showed that the presence of more Th1 and Th17 cells correlated with a higher RANKL/OPG ratio, whereas the presence of more Th2 cells correlated with a lower RANKL/OPG ratio. Th1 and Th17 cells are positively correlated and Th2 cells are negatively correlated with the RANKL/OPG ratio. Our data suggest that T‐helper cell polarization is closely linked to the RANKL/OPG ratio in gingival tissues from chronic periodontitis patients.