bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extending the Sensitivity of CEST NMR Spectroscopy to Micro‐to‐Millisecond Dynamics in Nucleic Acids Using High‐Power Radio‐Frequency Fields
Authors: Rangadurai Atul , Shi Honglue , Al‐Hashimi Hashim M. 
Published: March 2020

AbstractBiomolecules undergo motions on the micro‐to‐millisecond timescale to adopt low‐populated transient states that play important roles in folding, recognition, and catalysis. NMR techniques, such as Carr–Purcell–Meiboom–Gill (CPMG), chemical exchange saturation transfer (CEST), and R1ρ are the most commonly used methods for characterizing such transitions at atomic resolution under solution conditions. CPMG and CEST are most effective at characterizing motions on the millisecond timescale. While some implementations of the R1ρ experiment are more broadly sensitive to motions on the micro‐to‐millisecond timescale, they entail the use of selective irradiation schemes and inefficient 1D data acquisition methods. Herein, we show that high‐power radio‐frequency fields can be used in CEST experiments to extend the sensitivity to faster motions on the micro‐to‐millisecond timescale. Given the ease of implementing high‐power fields in CEST, this should make it easier to characterize micro‐to‐millisecond dynamics in biomolecules.
Triple‐Gaussian distributed activation energy model for the thermal degradation of coal and coal chars under a CO2 atmosphere
Authors: Wang Haopeng , Ti Shuguang 
Published: March 2020

AbstractCoal and coal char thermal degradation in a CO2 atmosphere is particularly important to understand and model as a rate‐determining step in the gasification process. The work presented here aims to provide a global kinetic model that accurately represents the thermal degradation of Sanxing (SX) coal and coal char under a CO2 atmosphere and to determine the kinetic parameters of the thermal degradation. In the work presented, a novel approach has been used that involves a triple‐Gaussian DAEM that simultaneously considers the primary pyrolysis, secondary pyrolysis, and the process of newly generated char gasified by CO2. The result of the model shows accurate reproduction of the thermal degradation behavior of SX coal and chars and provides significant information about the relative occurrence of the three steps. For SX coal and Char500, the residual error of the triple‐Gaussian DAEM is approximately 0.35 to 0.22 times that of the double Gaussian DAEM. For Char850, the ratio is lower, approximately 0.12 times that of the double Gaussian DAEM. This indicates that the triple‐Gaussian DAEM is more suitable for describing the thermal degradation of chars acquired at high temperatures (500–850°C) under a CO2 atmosphere.
Flexible poly(styrene‐ethylene‐butadiene‐styrene) hybrid nanofibers for bioengineering and water filtration applications
Authors: Avci Huseyin , Akkulak Esra , Gergeroglu Hazal , Ghorbanpoor Hamed , Uysal Onur , Eker Sariboyaci Ayla , Demir Bahar , Soykan Merve Nur , Pat Suat , Mohammadigharehbagh Reza , Özel Ceren , Cabuk Ahmet , Doğan Güzel Fatma 
Published: March 2020

AbstractAmong the thermoplastic elastomers that play important roles in the polymer industry due to their superior properties, styrene‐based species and polyurethane block copolymers are of great interest. Poly(styrene‐ethylene‐butadiene‐styrene) (SEBS) as a triblock copolymer seems to have the potential to meet many demands in different applications due to various industrial requirements where durability, biocompatibility, breaking elongation, and interfacial adhesion are important. In this study, the SEBS triblock copolymer was functionalized with natural (Satureja hortensis, SH) and synthetic (nanopowder, TiO2) agents to obtain composite nanofibers by electrospinning and electrospraying methods for use in biomedical and water filtration applications. The results were compared with thermoplastic polyurethane (TPU) composite nanofibers, which are commonly used in these fields. Here, functionalized SEBS nanofibers exhibited antibacterial effect while at the same time improving cell viability. In addition, because of successful water filtration by using the SEBS composite nanofibers, the material may have a good potential to be used comparably to TPU for the application.
Ultra‐high compression and wear resistant hybrid filled polyimide composite: Synergistic effect of Fe2O3 decorated RGO
Authors: Liu Hong , Jia Yongfeng , Wang Hongding , Duan Chunjian , Wang Tingmei , Wang Qihua 
Published: March 2020

AbstractHerein, the tribological performance, thermal and compression resistance behavior of polyimide (PI) reinforced by Fe2O3 decorated reduced graphene is systematically investigated. The remarkable synergistic effect of Fe2O3 decorated reduced graphene oxide (RGO) is demonstrated in its PI wear resistance, and PI/RGO/Fe2O3 composites show good thermal stability and much higher compression resistant ability than PI, PI/RGO, and PI/Fe2O3 composites when the filling contents are same. Additionally, the PI/RGO/Fe2O3 composites also exhibited ultra‐wear‐resistant properties under high load condition, and the lowest wear rate is 3.18 × 10−8 mm3N−1 m−1, which is an order of magnitude lower than that of pure PI. The investigation of its tribological mechanism also showed strong synergistic effect and interface force of Fe2O3 decorated RGO, which contribute to its high‐performance friction‐reducing behaviors. These findings give an inside view to Fe2O3 decorated RGO and its polyimide composites, and open an avenue for the graphene oxide (GO) based composite to act as compression wear‐resisting solid fillers and lubricants when polymer composite with excellent compressive, thermal and tribological properties is required.
Segmental relaxations and other insights into filler‐mediated interactions for carbon black‐filled polybutadiene rubber
Authors: Zhang Yuanhong , Zhou Hongbin 
Published: March 2020

AbstractThe role of interaction with filler particles in modifying segmental relaxations of elastomers is still not fully clear. This work examines the glass and melting transition of unvulcanized and vulcanized polybutadiene rubber filled with carbon black. It is found that for uncured rubbers, the calorimetric glass and melting transition temperatures are unaffected by the presence of carbon black, without invoking the concept of restricted chains near filler. In quenched vulcanizates, the increment in segmental relaxation with filler loading is detected, which is attributed to the reduction in chemical crosslink density caused by filler agglomeration. On the other hand, the crystalline part constrains the molecular motion in amorphous regions such that the glass transition temperature is raised when the crystallinity is large. This study reveals that the only effect of carbon black is to influence chemical crosslinks through filler networking and then change in segmental relaxations is detectable.
Coextrusion and biaxial orientation of multi‐microlayer films
Authors: Chiu Hsien‐Tang , Yu Chin‐Yang , Huang Chang‐Min , Lin Bang‐Shuan 
Published: March 2020

AbstractIn this study, the multi‐microlayer films (MMFs) prepared by the coextrusion of the corresponding polymers using a feed block design are reported. The alternating layers of the linear low‐density poly(ethylene) and ethylene vinyl alcohol polymers are used to produce the 3‐layered and 100‐layered MMFs with the total thickness of around 640 μm. The MMFs are going through biaxial orientation and heat treatment which can change the morphologies and physical properties and reduce the thickness of the films to several micrometers. The differences in crystallinity, melting temperature, interface physical properties, tensile strength, and water vapor transmission rate of the MMFs are fully investigated. The intermolecular interaction of the 100‐layered MMFs is much higher than that of the 3‐layered MMFs possibly due to the tightly bonded layers which lead to the disappearance of the interface layers following by orientation. The MMFs are successfully prepared by coextrusion following by biaxial orientation and heat treatment of two or more different kinds of polymers with very different intrinsic properties. This MMFs exhibit excellent compatibility, mechanical property and water resistance characteristics which have potential uses in the composite materials for food and electronic packaging applications.
Development of microsatellite markers for the perennial plant Tofieldia calyculata
Authors: Vlasta Tomáš , Jarošová Andrea , Šurinová Maria , Münzbergová Zuzana 
Published: March 2020

PremisePolymorphic microsatellite markers were developed to study genetic diversity and genetic structure of populations of the locally endangered species Tofieldia calyculata (Tofieldiaceae).Methods and ResultsNineteen polymorphic microsatellite loci were developed using DNA‐enriched libraries sequenced by Ilumina technology and were then used to genotype 101 individuals from five populations from Austria, Slovakia, Poland, and the Czech Republic. Of the markers tested, 68% were polymorphic in four of the five investigated populations, with one marker polymorphic in all populations. The number of alleles per locus in the populations ranged from one to 11. Levels of observed and expected heterozygosity ranged from 0.00 to 0.75 and from 0.00 to 0.84, respectively. Moreover, six of the 19 loci amplified when tested in the congeneric species T. pusilla.ConclusionsThe 19 newly developed microsatellite markers can be used to describe genetic diversity and population structure of populations of T. calyculata.
A patient‐derived xenograft and a cell line derived from it form a useful preclinical model for small bowel adenocarcinoma
Authors: Yamano Tomoki , Kubo Shuji , Tomita Naohiro 
Published: March 2020

AbstractBasic and clinical studies on small bowel adenocarcinoma (SBA) are limited due to the rare nature of this cancer. We established a patient‐derived xenograft (PDX) model from the tumor tissue of an advanced SBA patient with liver and peritoneal metastasis, and a cell line from the PDX. In the PDX model, compared to the control group, 5‐fluorouracil (5‐FU) treatment resulted in statistically significant tumor growth inhibition (TGI), while oxaliplatin (OHP) and irinotecan had no significant inhibitory effects. In combination with 5‐FU, OHP showed the highest rate of TGI. The IC50 for OHP was significantly lower than those for paclitaxel, gemcitabine, and trifluorothymidine in the PDX‐derived cell line when compared to in HT29, a colon cancer cell line. Genetic analysis of the patient tumor, PDX tumor, and the cell line demonstrated consistency in the microsatellite status and mutations in TP53, APC, HRAS, CSF1R, FGFR3, FLT3, PDGFRA, and RET genes. However, the PDX tumor alone had additional mutations, indicating that the PDX‐derived cell line may support the unstable genetic status of the PDX. Our findings confirmed the effectiveness of the combination of OHP and 5‐FU, which is a common treatment for advanced SBA and advanced colorectal cancer, in a preclinical model. This preclinical model of SBA can help in further understanding the biology of SBA.
Dental manifestations of hypophosphatasia in children and the effects of enzyme replacement therapy on dental status: A series of clinical cases
Authors: Kiselnikova Larisa , Vislobokova Elena , Voinova Victoria 
Published: March 2020

AbstractThe most frequent dental signs of hypophosphatasia in children are premature loss of primary teeth, decrease in height of alveolar bone, and malocclusions. Enzyme replacement therapy with Asfotase alfa might be associated with stabilization of dental status.
Harvest interval effects on the persistence and productivity of alfalfa grown as a monoculture or in mixtures in the southeastern United States
Authors: Quinby Marcia P. , Nave Renata L. G. , Bates Gary E. , McIntosh David 
Published: March 2020

AbstractFor alfalfa (Medicago sativa L.) to be profitable in the southeastern United States, enhanced persistence is required. However, studies assessing alfalfa's persistence in monoculture or mixtures in the region are limited. We aimed to determine the persistence and productivity of alfalfa and alfalfa–grass mixtures subjected to different harvest intervals. Three species combinations were established in 2015: alfalfa (A), alfalfa–tall fescue [Schenodorus arundinaceus (Schreb.) Dumort] (ATF), and alfalfa–bermudagrass [Cynodon dactylon (L.) Pers.] (AB). These were subjected to four harvest intervals (21, 28, 35, and 42 d) during the 2016, 2017, and 2018 growing seasons. Total forage accumulation (FA) was quantified during 2017 and 2018 and nutritive value and stem density were measured at the first and last harvests in those years. Forage accumulation decreased in all species combinations after 2 yr of management (A: 21 d, –63%; 28 d, –66%; 35 d, –50%; 42 d, –31%; AB: 21 d, –22%; 28 d, –59%; 35 d, –34%; 42 d, –19%; ATF: 21 d, –41%; 28 d, –62%; 35 d, –64%; 42 d, –41%), reflecting decreased alfalfa stem density, especially for A and AB. The differences in alfalfa stem density between the first and last harvests depended on the species. No differences were observed in ATF mixtures but for AB and A, longer harvest intervals had up to 90% fewer stems, thus decreasing alfalfa's persistence in the field. Lower stem density was observed for the 21‐d harvest interval; therefore, longer intervals could result in better field performance.
Identification and Nanomechanical Characterization of the HIV Tat‐Amyloid β Peptide Multifibrillar Structures
Authors: Feng Qiying , Hong Yue , Pradeep Nidamanuri Naga , Yang Chuanxu , Li Qiang , Dong Mingdong 
Published: March 2020

AbstractHIV transactivator of transcription (Tat) protein could interact with amyloid β (Aβ) peptide which cause the growth of Aβ plaques in the brain and result in Alzheimer's disease in HIV‐infected patients. Herein, we employ high‐resolution atomic force microscopy and quantitative nanomechanical mapping to investigate the effects of Tat protein in Aβ peptide aggregation. Our results demonstrate that the Tat protein could bind to the Aβ fibril surfaces and result in the formation of Tat‐Aβ multifibrillar structures. The resultant Tat‐Aβ multifibrillar aggregates represent an increase in stiffness compared with Aβ fibrils due to the increase in β‐sheet formation. The identification and characterization of the Tat‐Aβ intermediate aggregates is important to understanding the interactions between Tat protein and Aβ peptide, and the development of novel therapeutic strategy for Alzheimer's disease‐like disorder in HIV infected individuals.
Pentafluoroethylaluminates: A Combined Synthetic, Spectroscopic, and Structural Study
Authors: Bischoff Lisa A. , Riefer Jarno , Wirthensohn Raphael , Bischof Tobias , Bertermann Rüdiger , Ignat'ev Nikolai V. , Finze Maik 
Published: March 2020

AbstractSalts of the tetrakis(pentafluoroethyl)aluminate anion [Al(C2F5)4]− were obtained from AlCl3 and LiC2F5. They were isolated with different counter‐cations and characterized by NMR and vibrational spectroscopy and mass spectrometry. Degradation of the [Al(C2F5)4]− ion was found to proceed via 1,2‐fluorine shifts and stepwise loss of CF(CF3) under formation of [(C2F5)4−nAlFn]− (n=1–4) as assessed by NMR spectroscopy and mass spectrometry and supported by results of DFT calculations. In addition, the [(C2F5)AlF3]− ion was structurally characterized.
Kinetic Stabilities and Exchange Dynamics of Water‐Soluble Bis‐Formamide Caviplexes Studied Using Diffusion‐Ordered NMR Spectroscopy (DOSY)
Authors: Escobar Luis , Li Yong‐Sheng , Cohen Yoram , Yu Yang , Rebek Julius , Ballester Pablo 
Published: March 2020

AbstractA deep cavitand binds long‐chain trans,trans‐ and trans,cis‐bis‐formamide isomers in water solution giving a pair of caviplexes in a ca. 60:40 ratio. Both caviplexes display in/out guest exchange dynamics that are slow on the 1H NMR chemical shift timescale, but fast on the EXSY timescale. We apply diffusion‐ordered NMR spectroscopy (DOSY) to characterize the caviplexes. On the diffusion timescale, the guest in/out exchange processes feature intermediate dynamics allowing the assessment of their kinetic stabilities. We found that the trans,cis‐bis‐formamide isomers form kinetically more stable caviplexes than the trans,trans‐counterparts. We also show that the kinetic stabilities of the bis‐formamide caviplexes relate well with their relative thermodynamic stabilities. Fortunately, the tuning of the DOSY parameters allowed the observation of the exchange dynamics as slow processes on the experiment timescale.
3D Nitrogen‐Doped Graphene Encapsulated Metallic Nickel–Iron Alloy Nanoparticles for Efficient Bifunctional Oxygen Electrocatalysis
Authors: Wang Zhaoyang , Liao Xiaobin , Lin Zifeng , Huang Fuzhi , Jiang Yalong , Owusu Kwadwo Asare , Xu Lin , Liu Ziang , Li Jiantao , Zhao Yan , Cheng Yi‐Bing , Mai Liqiang 
Published: March 2020

AbstractInvited for the cover of this issue is Liqiang Mai and co‐workers at Wuhan University of Technology. The image depicts Ni3Fe alloy nanoparticles encapsulated in N‐doped graphene as an efficient bifunctional oxygen electrocatalyst toward rechargeable Zn‐air batteries, which is expected to drive the electric vehicle. Read the full text of the article at 10.1002/chem.201904722.
Mechanochemical Synthesis of Short DNA Fragments
Authors: Thorpe James D. , O'Reilly Daniel , Friščić Tomislav , Damha Masad J. 
Published: March 2020

AbstractWe demonstrate the first mechanochemical synthesis of DNA fragments by ball milling, enabling the synthesis of oligomers of controllable sequence and length using multi‐step, one‐pot reactions, without bulk solvent or the need to isolate intermediates. Mechanochemistry allowed for coupling of phosphoramidite monomers to the 5′‐hydroxyl group of nucleosides, iodine/water oxidation of the resulting phosphite triester linkage, and removal of the 5′‐dimethoxytrityl (DMTr) protecting group in situ in good yields (up to 60 % over three steps) to produce DNA dimers in a one‐pot manner. H‐Phosphonate chemistry under milling conditions enabled coupling and protection of the H‐phosphonate linkage, as well as removal of the 5′‐DMTr protecting group in situ, enabling a one‐pot process with good yields (up to 65 % over three steps, or ca. 87 % per step). Sulfurization of the internucleotide linkage was possible using elemental sulfur (S8) or sulfur transfer reagents, yielding the target DNA phosphorothioate dimers in good yield (up to 80 % over two steps). This work opens the door to creation of solvent‐free synthesis methodologies for DNA and RNA therapeutics.
Testing the Italian version of the Cyberchondria Severity Scale and a metacognitive model of cyberchondria
Authors: Marino Claudia , Fergus Thomas A. , Vieno Alessio , Bottesi Gioia , Ghisi Marta , Spada Marcantonio M. 
Published: March 2020

Cyberchondria refers to the tendency to excessively and compulsively search for online medical information despite the distress experienced, with consequent impairment of daily‐life activities. The current two studies sought to explore (i) the factor structure of the Italian version of the Cyberchondria Severity Scale (CSS) and (ii) a metacognitive model of cyberchondria.Participants were Italian community adults who reported using the Internet to search for health‐related information (Study 1: N = 374, Study 2: N = 717). Results from Study 1 supported the Italian version of the CSS exhibiting a five‐factor structure, with the resulting scales demonstrating good internal consistency, 5‐week test–retest reliability, and generally strong correlations with indices of health anxiety. In Study 2, results of a path analysis showed that the negative metacognitive belief domain (“thoughts are uncontrollable”) shared the strongest direct association with each of the five dimensions of cyberchondria, followed by beliefs about rituals. Consistently, the strongest indirect associations were found between “thoughts are uncontrollable” and all the five cyberchondria dimensions via beliefs about rituals. These results provide support for an Italian version of the CSS and the metacognitive conceptualization of cyberchondria.
Optimal spatial prioritization of control resources for elimination of invasive species under demographic uncertainty
Authors: Pepin Kim M. , Smyser Timothy J. , Davis Amy J. , Miller Ryan S. , McKee Sophie , VerCauteren Kurt C. , Kendall William , Slootmaker Chris 
Published: March 2020

AbstractPopulations of invasive species often spread heterogeneously across a landscape, consisting of local populations that cluster in space but are connected by dispersal. A fundamental dilemma for invasive species control is how to optimally allocate limited fiscal resources across local populations. Theoretical work based on perfect knowledge of demographic connectivity suggests that targeting local populations from which migrants originate (sources) can be optimal. However, demographic processes such as abundance and dispersal can be highly uncertain, and the relationship between local population density and damage costs (damage function) is rarely known. We used a metapopulation model to understand how budget and uncertainty in abundance, connectivity, and the damage function, together impact return on investment (ROI) for optimal control strategies. Budget, observational uncertainty, and the damage function had strong effects on the optimal resource allocation strategy. Uncertainty in dispersal probability was the least important determinant of ROI. The damage function determined which resource prioritization strategy was optimal when connectivity was symmetric but not when it was asymmetric. When connectivity was asymmetric, prioritizing source populations had a higher ROI than allocating effort equally across local populations, regardless of the damage function, but uncertainty in connectivity structure and abundance reduced ROI of the optimal prioritization strategy by 57% on average depending on the control budget. With low budgets (monthly removal rate of 6.7% of population), there was little advantage to prioritizing resources, especially when connectivity was high or symmetric, and observational uncertainty had only minor effects on ROI. Allotting funding for improved monitoring appeared to be most important when budgets were moderate (monthly removal of 13–20% of the population). Our result showed that multiple sources of observational uncertainty should be considered concurrently for optimizing ROI. Accurate estimates of connectivity direction and abundance were more important than accurate estimates of dispersal rates. Developing cost‐effective surveillance methods to reduce observational uncertainties, and quantitative frameworks for determining how resources should be spatially apportioned to multiple monitoring and control activities are important and challenging future directions for optimizing ROI for invasive species control programs.