bluuebunny/crossref_metadata_2025_split huggingface dataset:
Approaching the Integer‐Charge Transfer Regime in Molecularly Doped Oligothiophenes by Efficient Decarboxylative Cross‐Coupling
Authors: Liu Jiang Tian , Hase Hannes , Taylor Sarah , Salzmann Ingo , Forgione Pat 
Published: January 2020

AbstractA library of symmetrical linear oligothiophene was prepared employing decarboxylative cross‐coupling reaction as the key transformation. Thiophene potassium carboxylate salts were used as cross‐coupling partners without the need of co‐catalyst, base, or additives. This method demonstrates complete chemoselectivity and is a comprehensive greener approach compared to the existing methods. The modularity of this approach is demonstrated with the preparation of discreet oligothiophenes with up to 10 thiophene repeat units. Symmetrical oligothiophenes are prototypical organic semiconductors where their molecular electrical doping as a function of the chain length can be assessed spectroscopically. An oligothiophene critical length for integer charge transfer was observed to be 10 thiophene units, highlighting the potential use of discrete oligothiophenes as doped conduction or injection layers in organic electronics applications.
Enantioselective Synthesis of 1,12‐Disubstituted [4]Helicenes
Authors: Hartung Thierry , Machleid Rafael , Simon Martin , Golz Christopher , Alcarazo Manuel 
Published: January 2020

AbstractA highly enantioselective synthesis of 1,12‐disubstituted [4]carbohelicenes is reported. The key step for the developed synthetic route is a Au‐catalyzed intramolecular alkyne hydroarylation, which is achieved with good to excellent regio‐ and enantioselectivity by employing TADDOL‐derived (TADDOL=α,α,α,α‐tetraaryl‐1,3‐dioxolane‐4,5‐dimethanol) α‐cationic phosphonites as ancillary ligands. Moreover, an appropriate design of the substrate makes the assembly of [4]helicenes of different substitution patterns possible, thus demonstrating the synthetic utility of the method. The absolute stereochemistry of the newly prepared structures was determined by X‐ray crystallography and characterization of their photophysical properties is also reported.
Regulation of natural convection heat transfer for SiO2–solar salt nanofluids by optimizing rectangular vessels design
Authors: Hu Yanwei , Zhang Borui , Tan Kaiyu , He Yurong , Zhu Jiaqi 
Published: January 2020

AbstractNatural convection heat transfer of molten salt is widely used in concentrated solar plants, such as the solar receiver, the single‐tank thermal energy storage system, and so forth. Meanwhile, adding nanoparticles into molten salts to form nanofluids can obviously improve the thermal properties of the working medium. However, the heat transfer performance of the molten salt‐based nanofluids has not been investigated extensively, and the action mechanism between base fluids and nanoparticles is still unclear. In the present work, a lattice Boltzmann model considering fluid and nanoparticles as two different phases was developed, and various interactions were taken into consideration. Meanwhile, the effects of nanoparticle concentrations, aspect ratios of the rectangular vessel, and Ra on natural convection heat transfer of solar salt‐based SiO2 nanofluids were analysed. The results show that specific heat capacity contributes substantially to heat transfer for all aspect ratios, and the maximum enhancement of natural convection heat transfer is obtained with a mass fraction of 1.0%. However, increase in Ra intensifies the effect of viscosity and weakens the heat transfer enhancement. Through interaction analysis, it indicated that nanoparticles tend to be driven to the top area of the rectangular vessel by temperature difference, driving force, and drag force. Meanwhile, a Nu enhancement contour was provided to optimize the design of a single energy storage tank.
Photodegradation of low‐density polyethylene with prooxidant and photocatalyst
Authors: Gharehdashli Abdolnaser , Mortazavi Saeed , Rashidi Hamed 
Published: January 2020

AbstractLow‐density polyethylene (LDPE) composite films with trisilver phosphate (Ag3PO4) and cadmium selenide (CdSe) particles as photocatalysts and manganese stearate as prooxidant were prepared. The film samples were irradiated under UV and visible light and their photodegradation were evaluated using Fourier‐transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. The carbonyl index of the photocatalyst containing samples was very higher than the pure irradiated LDPE and even prooxidant containing film. The morphologies of the irradiated composite films were completely changed and had many cavities and cracks. The thermal stability of the composites was very lower than the pure polyethylene. However the crystallinity of the LDPE films with photocatalysts was enhanced contrarily the LDPE film with manganese stearate. Generally the results showed that the combination of the prooxidant with photocatalyst have synergistic effect on the photodegradation of the LDPE and can be used to accelerate the degradation of the polyethylene films.
Preparation and characterization of cyclodextrin microencapsulated ammonium polyphosphate and its application in flame retardant polypropylene
Authors: Ding Siyin , Liu Peng , Zhang Shimin , Ding Yanfen , Wang Feng , Gao Chong , Yang Mingshu 
Published: January 2020

AbstractA novel microencapsulated ammonium polyphosphate (MAPP) with shell of crosslinked β‐cyclodextrin (HDI‐CD) was prepared. The HDI‐CD shell had a fibrous structure and covered with good completeness on the APP core, and a solid chemical bonding was found between the APP core and HDI‐CD shell. The microcapsules were more hydrophobic than the pristine APP. When compounded within polypropylene (PP), the MAPP exhibited good compatibility and dispersibility. The combustion testing results showed that the novel all‐in‐one intumescent flame retardant had efficient flame retardancy for PP materials.
Seasonal phenotype‐specific expression of microRNAs during metamorphosis in the European map butterfly Araschnia levana
Authors: Mukherjee Krishnendu , Baudach Arne , Vogel Heiko , Vilcinskas Andreas 
Published: January 2020

AbstractThe European map butterfly (Araschnia levana) is a well‐known example of seasonal polyphenism because the spring and summer imagoes exhibit distinct morphological phenotypes. The day length and temperature during larval and prepupal development determine whether spring or summer imagoes emerge after metamorphosis. Inspired by the fundamentally different transcriptomic profiles in prepupae developing from larvae exposed to long days or short days, we postulate that posttranscriptional epigenetic regulators such as microRNAs (miRNAs) may contribute to the epigenetic control of seasonal polyphenism in A. levana. To test this hypothesis, we used microarrays containing over 2,000 insect miRNAs to identify candidate regulators that are differentially expressed in last‐instar larvae or pupae developing under long‐day or short‐day conditions. We used our transcriptomic database to identify potential 3′‐untranslated regions of messenger RNAs to predict miRNA targets by considering both base pair complementarity and minimum free energy hybridization. This approach resulted in the identification of multiple targets of miRNAs that were differentially regulated in polyphenic morphs of A. levana including a candidate (miR‐2856‐3p) regulating the previously identified diapause bioclock protein gene. In conclusion, the expression profiling of miRNAs provided insights into their possible involvement in seasonal polyphenism of A. levana and offer an important resource for further studies.
Coronary total occlusion and minimalist approach: When less is more
Authors: Musumeci Giuseppe , Baralis Giorgio 
Published: January 2020

Key Points
The minimalistic hybrid algorithm is a possible alternative sequence of steps in the setting of coronary total occlusion (CTO) recanalization.
A fully transradial approach in CTO is a valid alternative to transfemoral approach with a high rate of success.
A minimalistic hybrid algorithm maintains all the available possible options for crossing the CTO lesions.
Mid‐term results of in situ fenestration stented with balloon‐expandable bare metal stents during thoracic endovascular aortic repair
Authors: Bai Jun , Liu Yandong , Jin Jie , Wu Jianjin , Qu Lefeng 
Published: January 2020

AbstractPurposeTo assess the safety, feasibility and effectiveness of balloon‐expandable bare metal stents (BMS) as bridge stents during thoracic endovascular aortic repair (TEVAR).Materials and MethodsRetrospective analysis was conducted on 103 consecutive patients who underwent TEVAR procedures from December 2015 to March 2018. Thirty‐one patients fulfilled requirements for inclusion and exclusion in the analysis. Thirty‐three in situ fenestration (ISF) procedures (single fenestration [n = 29]; dual fenestration [n = 2]) were performed in the 31 patients (67.7% men; median age, 61.5 year) who underwent TEVAR for thoracic lesions (aortic dissection [n = 23], aortic aneurysm [n = 3], aortic ulcer [n = 5]) with 34 stents (33 balloon‐expandable BMS, 1 covered stents) implanted in supraaortic arteries. The success rate of overall intervention, fenestration, and implantation of BMS was recorded. The therapeutic effects and complications during admission and follow‐up (median 29.7 months, range 18–45 months) were the primary outcomes.ResultsThe technical success rate was 90.3% (28/31). All thoracic lesions were totally excluded. Major complications (6.5%) were one dissection in the left subclavian artery (n = 1) and thrombus formation (n = 1). Minor complications (12.9%) were hematoma (n = 1), and type III endoleak (n = 3). During follow‐up, no endoleak developed and all fenestrated branch arteries were patent, except for one left subclavian artery dissection and occlusion.ConclusionsUse of balloon‐expandable BMS in ISF is safe and effective in reconstruction of supraarotic arteries during TEVAR.
Epitaxial Cubic Silicon Carbide Photocathodes for Visible‐Light‐Driven Water Splitting
Authors: Han Xiuxiu , Heuser Steffen , Tong Xili , Yang Nianjun , Guo Xiang‐Yun , Jiang Xin 
Published: January 2020

AbstractCubic silicon carbide (3C‐SiC) material feature a suitable bandgap and high resistance to photocorrosion. Thus, it has been emerged as a promising semiconductor for hydrogen evolution. Here, the relationship between the photoelectrochemical properties and the microstructures of different SiC materials is demonstrated. For visible‐light‐derived water splitting to hydrogen production, nanocrystalline, microcrystalline and epitaxial (001) 3C‐SiC films are applied as the photocathodes. The epitaxial 3C‐SiC film presents the highest photoelectrochemical activity for hydrogen evolution, because of its perfect (001) orientation, high phase purity, low resistance, and negative conduction band energy level. This finding offers a strategy to design SiC‐based photocathodes with superior photoelectrochemical performances.
Frequent KRAS and HRAS mutations in squamous cell papillomas of the head and neck
Authors: Sasaki Eiichi , Masago Katsuhiro , Fujita Shiro , Hanai Nobuhiro , Yatabe Yasushi 
Published: January 2020

AbstractSquamous cell papilloma (SCP) is a benign neoplasm of the head and neck. Human papillomavirus (HPV) has been reported to be a tumourigenic factor for SCP. However, not all SCPs are positive for HPV, suggesting that other possible mechanisms are involved in their development. In this study, we examined the mutational status of 51 SCPs using targeted panel sequencing in addition to HPV status using GP5+/GP6+ PCR. HPV DNA was detected in 6 (12%) SCPs, while KRAS and HRAS mutations were detected in 18 (35%) and 17 (33%) SCPs, respectively. Notably, KRAS mutations, HRAS mutations and HPV infection were mutually exclusive. The larynx and trachea (4/7, 57%) were more preferentially infected by HPV than the other sites (2/44, 5%, p = 0.0019) and HPV was associated with multifocal development (4/5, 80%). In contrast, KRAS and HRAS mutations in SCPs were evenly distributed across the anatomical sites and found only in single SCPs. In conclusion, this study demonstrated that HPV was not frequently involved in SCPs and that RAS mutations were more common alterations. In contrast to inverted sinonasal papillomas and oncocytic sinonasal papillomas, SCP may not be a precursor lesion of carcinoma, because these aetiological events in SCP are distinct from squamous cell carcinoma in the same sites.
Color measurement of single yarn based on hyperspectral imaging system
Authors: Zhang Jianxin , Wu Junkai , Zhang Xinen , Hu Xudong 
Published: January 2020

AbstractThis article proposed a novel approach to color measurement of a single yarn using hyperspectral imaging system (HIS). Due to the size of a single yarn, it is impossible for spectrophotometers to measure its color directly. The HIS can acquire the spectral reflectance of continuous bands within a region of interest on a yarn sample, which can achieve color measurement of a single yarn compared with traditional spectrophotometers. A single yarn is segmented from the background by a spectral matching method through adaptively setting threshold of Fréchet distance values. The spectral reflectance of single yarn is specified by a method that lightness of pixels used as weight. The experiment based on Pantone Cotton Chip Set shows that the interinstrument agreement between the HIS and a standard spectrophotometer Datacolor SF650 has a significant improvement after using the R‐Model, and the average percentage improvement of the color difference is up to 54.99%. The yarn segmentation comparative experimental results show that the proposed method to segment single yarn from background is better in retaining the edge information of the yarn than the modified K‐means clustering method, and the color of the yarn segmented by the proposed method is more similar to the actual color of single yarn.
Rapid recovery of ecosystem function following extreme drought in a South African savanna grassland
Authors: Wilcox Kevin R. , Koerner Sally E. , Hoover David L. , Borkenhagen Andrea K. , Burkepile Deron E. , Collins Scott L. , Hoffman Ava M. , Kirkman Kevin P. , Knapp Alan K. , Strydom Tercia , Thompson Dave I. , Smith Melinda D. 
Published: January 2020

AbstractClimatic extremes, such as severe drought, are expected to increase in frequency and magnitude with climate change. Thus, identifying mechanisms of resilience is critical to predicting the vulnerability of ecosystems. An exceptional drought (<first percentile) impacted much of southern Africa during the 2015 and 2016 growing seasons, including the site of a long‐term fire experiment in Kruger National Park, South Africa. Prior to the drought, experimental fire frequencies (annual, triennial, and unburned) created savanna grassland plant communities that differed in composition and function, providing a unique opportunity to assess ecosystem resilience mechanisms under different fire regimes. Surprisingly, aboveground net primary productivity (ANPP) recovered fully in all fire frequencies the year after this exceptional drought. In burned sites, resilience was due mostly to annual forb ANPP compensating for reduced grass ANPP. In unburned sites, resilience of total and grass ANPP was due to subdominant annual and perennial grass species facilitating recovery in ANPP after mortality of other common grasses. This was possible because of high evenness among grass species in unburned sites predrought. These findings highlight the importance of both functional diversity and within‐functional group evenness as mechanisms of ecosystem resilience to extreme drought.
Evaluating functional connectivity in a small agricultural catchment under contrasting flood events by using UAV
Authors: Calsamiglia Aleix , Gago Jorge , Garcia‐Comendador Julián , Bernat Josep Fortesa , Calvo‐Cases Adolfo , Estrany Joan 
Published: January 2020

ABSTRACTConcentrated erosion, a major feature of land degradation, represents a serious problem for soil and water resources management and a threat to ecosystems. Understanding the internal mechanisms (de‐)coupling sediment pathways can improve the management and resilience of catchments. In this study, concentrated erosion and deposition forms were mapped accurately through field and aerial unmanned aerial vehicle (UAV) campaigns, in order to assess the evolution of connectivity pathways over a series of three contrasted and consecutive flood events occurring between October 2016 and January 2017 (return period ranging from 0.5 to 25 years) in a small Mediterranean agricultural catchment (Can Revull, Mallorca, Spain; 1.4 km2). In addition, a morphometric index of connectivity (IC) was used to identify the potential trajectories of different concentrated erosion forms and deposition areas. IC predictions were calibrated by identifying the optimal critical thresholds, i.e. those most consistent with field observations after each of the events studied. The results found that the index performed well in predicting the occurrence and the length/area of the different type of landforms, giving kappa (κ) coefficients of variation ranging between 0.21 and 0.92 and linear correlations R2 between 0.33 and 0.72. The type of landform affected the correspondence of IC predictions and field observations, with lower thresholds the greater the magnitude of their associated geomorphic processes. Rainfall magnitude proved to be a very important factor controlling the development of erosion and deposition landforms, with large differences in length/area between the contrasted events. The evolution of the observed trajectories revealed feedback dynamics between the structural and functional connectivity of the catchment, in which morphological changes determined the spatial distribution of the processes’ activity in the successive events and vice versa. © 2020 John Wiley & Sons, Ltd.
The predictability of stock market volatility in emerging economies: Relative roles of local, regional, and global business cycles
Authors: Bouri Elie , Demirer Riza , Gupta Rangan , Sun Xiaojin 
Published: January 2020

AbstractThis paper explores the role of business cycle proxies, measured by the output gap at the global, regional, and local levels, as potential predictors of stock market volatility in the emerging BRICS nations. We observe that the emerging BRICS nations display a rather heterogeneous pattern when it comes to the relative role of idiosyncratic factors as a predictor of stock market volatility. While domestic output gap is found to capture significant predictive information for India and China particularly, the business cycles associated with emerging economies and the world in general are strongly important for the BRIC countries and weakly for South Africa, especially in the postglobal financial crisis era. The findings suggest that despite the increase in the financial integration of world capital markets, emerging economies can still bear significant exposures to idiosyncratic risk factors, an issue of high importance for the profitability of global diversification strategies.
Experimental investigation of smart carbonated water injection method in carbonates
Authors: Soleimani Payam , Shadizadeh Seyed Reza , Kharrat Riyaz 
Published: January 2020

AbstractEnhanced oil recovery (EOR) has been noticed during recent years from reservoirs that are at the end of their life plateau or in which production has been declined. Two of these EOR methods are as follows: carbonated water and smart water injection. In carbonated water injection method, CO2‐contained water is injected in reservoirs in order to decrease free CO2 injection mobility, increase water viscosity, and store/remove produced greenhouse CO2 gas safely, and in smart water injection method, the ions in brine are modified in order to make controlled reactions with distributed ions on the surface of rock to cause more hydrocarbon recovery. In this paper, the combination of these two methods is investigated as hybrid smart carbonated water injection to find out the recovery factor change and effective mechanisms. Experimental core flooding setup is used for investigation of hybrid EOR injection applicability and mechanisms. Probable mechanisms are measured using different cores and five water samples are used for preparing carbonated water (at pressure of 2500 psi) including sea water (34 261 ppm), river water (1329 ppm), one of Iranian reservoir formation water (FW) (163 711 ppm), 10 times diluted FW (0.1 FW), and 100 times diluted FW (0.01 FW). The effect of both brine content and volume of CO2 is determined during hybrid EOR assessment. The main mechanisms activated including pH variation, oil swelling, oil viscosity reduction, ion concentration variation in brine and porous media, and wettability alteration have been investigated. Hybrid method resulted in highest recovery (70%) mainly due to ion exchange, wettability alteration, oil swelling, and permeability enhancement. In addition, type of salt concentration will affect recovery as 0.01 FW results in 8% and 16% additional oil recovery compared to sea and river waters, respectively. Coupling of CO2 and salts will increase recovery factor due to mechanisms activated by each of these factors as 0.01 FW results in 10% more oil recovery compared to FW. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.
Developmental trajectory of oligodendrocyte progenitor cells in the human brain revealed by single cell RNA sequencing
Authors: Perlman Kelly , Couturier Charles P. , Yaqubi Moein , Tanti Arnaud , Cui Qiao‐Ling , Pernin Florian , Stratton Jo Anne , Ragoussis Jiannis , Healy Luke , Petrecca Kevin , Dudley Roy , Srour Myriam , Hall Jeffrey A. , Kennedy Timothy E. , Mechawar Naguib , Antel Jack P. 
Published: January 2020

AbstractCharacterizing the developmental trajectory of oligodendrocyte progenitor cells (OPC) is of great interest given the importance of these cells in the remyelination process. However, studies of human OPC development remain limited by the availability of whole cell samples and material that encompasses a wide age range, including time of peak myelination. In this study, we apply single cell RNA sequencing to viable whole cells across the age span and link transcriptomic signatures of oligodendrocyte‐lineage cells with stage‐specific functional properties. Cells were isolated from surgical tissue samples of second‐trimester fetal, 2‐year‐old pediatric, 13‐year‐old adolescent, and adult donors by mechanical and enzymatic digestion, followed by percoll gradient centrifugation. Gene expression was analyzed using droplet‐based RNA sequencing (10X Chromium). Louvain clustering analysis identified three distinct cellular subpopulations based on 5,613 genes, comprised of an early OPC (e‐OPC) group, a late OPC group (l‐OPC), and a mature OL (MOL) group. Gene ontology terms enriched for e‐OPCs included cell cycle and development, for l‐OPCs included extracellular matrix and cell adhesion, and for MOLs included myelination and cytoskeleton. The e‐OPCs were mostly confined to the premyelinating fetal group, and the l‐OPCs were most highly represented in the pediatric age group, corresponding to the peak age of myelination. Cells expressing a signature characteristic of l‐OPCs were identified in the adult brain in situ using RNAScope. These findings highlight the transcriptomic variability in OL‐lineage cells before, during, and after peak myelination and contribute to identifying novel pathways required to achieve remyelination.